JP6723947B2 - Substrate pretreatment to reduce filling time in nanoimprint lithography - Google Patents

Description

[Cross-reference of related applications]
This application is a U.S. patent application entitled "SUBSTRATE PRETREATMENT FOR REDUCING FILL TIME IN NANOIMPRINT LITHOGRAPHY" filed September 8, 2015, entitled "SUBSTRATE PRETREATMENT FOR REDUCING FILL TIME IN NANOIMPRINT LITHOGRAPHY". No. 62/215,316, which is hereby incorporated by reference in its entirety.

The present invention relates to promoting throughput in a nanoimprint lithography process by treating a substrate (nanoimprint lithography substrate) to promote the spread of imprint resist on the substrate.

Since the semiconductor processing industry has been making efforts to increase the production efficiency while increasing the number of circuits per unit area, attention has been paid to the development of reliable and high-resolution patterning techniques. One such technique used today is commonly referred to as imprint lithography. The imprint lithography process is described in detail in many publications such as Patent Document 1, Patent Document 2 and Patent Document 3 (all of which are incorporated herein by reference). Other areas of development in which imprint lithography has been utilized include biotechnology, optical technology and mechanical systems.

The imprint lithography technique disclosed in each of the above-mentioned patent documents includes forming a relief pattern in an imprint resist and transferring a pattern corresponding to the relief pattern to a base substrate. The patterning process uses a template spaced from the substrate and a polymerizable composition (“imprint resist”) disposed between the template and the substrate. In some cases, the imprint resist may be placed on the substrate in the form of spaced discrete drops. After spreading the drops, the imprint resist is contacted with the template. After contacting the imprint resist with the template, the space between the substrate and the template is uniformly filled with the resist, and then by solidifying the imprint resist, a layer having a pattern matching the shape of the surface of the template is formed. It is formed. After solidification, the template is separated from the patterned layer so that the template and substrate are spaced apart.

Throughput in imprint lithography processes generally depends on a variety of factors. When the imprint resist is deposited on the substrate in the form of discrete, spaced-apart drops, at least part of the throughput depends on the efficiency and uniformity of the spread of the drops on the substrate. Spreading of the imprint resist can be hindered by factors such as gas voids between the drops and incomplete wetting of the substrate and/or template by the drops.

US Patent Application Publication No. 2004/0065252 US Patent No. 6,936,194 US Pat. No. 8,349,241

In a first general aspect, a nanoimprint lithography method includes disposing a pretreatment composition on a substrate to form a pretreatment coating on the substrate. The pretreatment composition contains a polymerizable component. Discontinuities of imprint resist are deposited on the pretreatment coating, each discontinuity covering a target area of the substrate. The imprint resist is a polymerizable composition. Each discontinuity in the imprint resist extends beyond its target area to form a composite polymerizable coating on the substrate. The composite polymerizable coating comprises a mixture of pretreatment composition and imprint resist. The composite polymerizable coating is contacted with the nanoimprint lithography template and polymerized to obtain a composite polymerized layer on the substrate. The interfacial energy between the pretreatment composition and air is greater than the interfacial energy between the imprint resist and air or between at least one component of the imprint resist and air.

Implementations of the first general aspect can include one or more of the following features.

In some cases, the difference between the interfacial energy between the pretreatment composition and air and the interfacial energy between the imprint resist and air, or the interfacial energy between the pretreatment composition and air, and the imprint The difference in interfacial energy between the resist component and air is 1 mN/m to 25 mN/m, 1 mN/m to 15 mN/m, or 1 mN/m to 7 mN/m. In some cases, the interfacial energy between the pretreatment composition and air is greater than the interfacial energy between the imprint resist and air.

The pretreatment composition may include a single monomer, may consist essentially of a single monomer, or may be a single monomer. In some cases, the pretreatment composition comprises more than one monomer. In some cases, the pretreatment composition comprises monofunctional, difunctional, or multifunctional acrylate monomers. In some examples, the pretreatment composition comprises trimethylolpropane triacrylate, trimethylolpropane ethoxylate triacrylate, 1,12-dodecanediol diacrylate, poly(ethylene glycol) diacrylate, tetraethylene glycol diacrylate, 1 , 3-adamantanediol diacrylate, nonanediol diacrylate, m-xylylene diacrylate, tricyclodecane dimethanol diacrylate, or any combination thereof. In one example, the pretreatment composition comprises 20 wt% to 40 wt% 1,12-dodecanediol diacrylate and 60 wt% to 80 wt% tricyclodecane dimethanol diacrylate, or about 30 wt% 1,2. It contains 12-dodecanediol diacrylate and about 70% by weight tricyclodecane dimethanol diacrylate.

In some cases, the imprint resist comprises 0% to 80%, 20% to 80%, or 40% to 80% by weight of one or more monofunctional acrylates and 20% to 98%. Wt% of one or more difunctional or polyfunctional acrylates, 1% to 10% by weight of one or more photoinitiators, and 1% to 10% of one or more of And a surfactant. In other cases, the imprint resist comprises 90% to 98% by weight of one or more difunctional or multifunctional acrylates and is substantially free of monofunctional acrylates. In some cases, the imprint resist comprises one or more monofunctional acrylates and 20% to 75% by weight of one or more difunctional or multifunctional acrylates.

The polymerizable component of the pretreatment composition and the polymerizable component of the imprint resist can be reacted to form a covalent bond during the polymerization of the composite polymerizable coating. In one example, the step of polymerizing the composite polymerizable coating comprises covalently bonding a component of the pretreatment composition and a component of the imprint resist. In some cases, the pretreatment composition and the imprint resist each include a monomer having a common functional group. In some cases, the common functional group is an acrylate group.

The step of disposing the pretreatment composition on the substrate may include spin-coating the pretreatment composition on the substrate. Optionally, the substrate comprises an adhesion layer and the step of disposing the pretreatment composition on the substrate comprises disposing the pretreatment composition on the adhesion layer. In some cases, disposing the discontinuous portion of imprint resist on the pretreatment coating comprises ejecting imprint resist drops on the pretreatment coating.

Contacting a discontinuity of the imprint resist with at least one other discontinuity of the imprint resist and forming a boundary between the two discontinuities prior to contacting the composite polymerizable coating with the nanoimprint lithography template. You can In some cases, each of the discontinuous portions of the imprint resist is separated from at least one other discontinuous portion of the imprint resist by the pretreatment composition upon contacting the composite polymerizable coating with the nanoimprint lithography template. There is.

The composite polymerizable coating may be a homogenous mixture of the pretreatment composition and the imprint resist. In some cases, the chemical composition of the composite polymeric layer is non-uniform.

Nanoimprint lithography laminates can be formed by the method of the first general aspect and one or more of the embodiments described above for the first general aspect.

In a second general aspect, the nanoimprint lithography laminate comprises a substrate and a composite polymeric layer formed on the surface of the substrate. The chemical composition of the composite polymerized layer is non-uniform and includes a plurality of central regions separated by boundaries, and the chemical composition of the composite polymerized layer at the boundaries is different from the chemical composition of the composite polymerized layer inside the central region.

Implementations of the second general aspect can include one or more of the following features.
The substrate typically includes an adhesion layer, and the composite polymeric layer is formed on the surface of the adhesion layer. In some cases, the central region and boundaries of the polymerized layer are formed by a heterogeneous mixture of the pretreatment composition and the imprint resist, and reacting the polymerizable component of the imprint resist with the polymerizable component of the pretreatment composition. At, a covalent bond is formed during the formation of the composite polymer layer. In some cases, the polymerizable component of the imprint resist and the polymerizable component of the pretreatment composition have common functional groups, such as acrylate groups.

The details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will be apparent from the specification, drawings and claims.

1 is a simplified side view of a lithographic system. FIG. 2 is a simplified side view of the substrate shown in FIG. 1 having a patterned layer formed on the substrate. It is a figure which shows the spreading interaction of the droplet of a 1st liquid and a 2nd liquid on a 1st liquid layer. It is a figure which shows the spreading interaction of the droplet of a 1st liquid and a 2nd liquid on a 1st liquid layer. It is a figure which shows the spreading interaction of the droplet of a 1st liquid and a 2nd liquid on a 1st liquid layer. It is a figure which shows the spreading interaction of the droplet of a 1st liquid and a 2nd liquid on a 1st liquid layer. FIG. 6 is a flow chart diagram illustrating a process that facilitates nanoimprint lithography throughput. It is a figure which shows a board|substrate. FIG. 6 shows a pretreatment coating disposed on a substrate. FIG. 6 shows the formation of a composite coating from imprinted resist drops placed on a substrate with a pretreatment coating. FIG. 6 shows the formation of a composite coating from imprinted resist drops placed on a substrate with a pretreatment coating. FIG. 6 shows the formation of a composite coating from imprinted resist drops placed on a substrate with a pretreatment coating. FIG. 6 shows the formation of a composite coating from imprinted resist drops placed on a substrate with a pretreatment coating. FIG. 6B is a cross-sectional view taken along the line ww of FIG. 6A. FIG. 6B is a cross-sectional view taken along line xx of FIG. 6B. It is sectional drawing which followed the yy line of FIG. 6C. It is sectional drawing which followed the zz line of FIG. 6D. FIG. 6 is a cross-sectional view of the pretreatment coating replaced with drops on the substrate. FIG. 6 is a cross-sectional view of the pretreatment coating replaced with drops on the substrate. FIG. 6 is a cross-sectional view of a template in contact with a homogeneous composite coating. FIG. 6 is a cross-sectional view of a template in contact with a homogeneous composite coating. It is sectional drawing of the obtained nanoimprint lithography laminated body. FIG. 6 is a cross-sectional view of a template in contact with a heterogeneous composite coating. FIG. 6 is a cross-sectional view of a template in contact with a heterogeneous composite coating. It is sectional drawing of the obtained nanoimprint lithography laminated body. FIG. 5 is a diagram showing an image of an imprint resist droplet after being spread on an adhesion layer of a substrate having no pretreatment coating, corresponding to Comparative Example 1. FIG. 5 shows an image of an imprint resist drop after spreading on the pretreatment coating described in Example 1. FIG. 6 shows an image of an imprint resist drop after spreading on the pretreatment coating described in Example 2. FIG. 5 shows an image of an imprint resist drop after spreading on the pretreatment coating described in Example 3. FIG. 5 is a diagram showing the defect density according to the pre-spreading time for the imprint resist and the pretreatment composition of Example 2. It is a figure which shows the drop diameter with respect to the spreading time of a pretreatment composition. It is a figure which shows the viscosity according to the partial composition of one component in a two-component pretreatment composition. FIG. 6 shows drop size versus time for various ratios of components in a two component pretreatment composition. It is a figure which shows the surface tension of the two-component pretreatment composition with respect to the fraction of one component in a two-component pretreatment composition.

FIG. 1 illustrates an imprint lithography system 100 of the type used for relief patterns on a substrate 102. The substrate 102 may include a base layer and an adhesion layer that adheres to the base layer. The substrate 102 can be coupled to the substrate chuck 104. As shown, the substrate chuck 104 is a vacuum chuck. However, the substrate chuck 104 may include, but is not limited to, vacuum, pin type, groove type, electromagnetic type, and the like. An example of a chuck is described in US Pat. No. 6,873,087, which is incorporated herein by reference. The substrate 102 and the substrate chuck 104 can be further supported by the stage 106. The stage 106 may provide motion for the x-axis, y-axis and z-axis. The stage 106, the substrate 102 and the substrate chuck 104 may be placed on the base layer.

The template 108 is separated from the substrate 102. The template 108 generally comprises a rectangular or square mesa 110 some distance from the surface of the template toward the substrate 102. Hereinafter, the mold and the mold may be referred to as a template. The surface of the mesa 110 can be patterned. In some cases, the mesa 110 is also referred to as the mold 110 or the mask 110. Template 108, mold 110 or both may be fused silica, quartz, silicon, silicon nitride, organic polymers, siloxane polymers, borosilicate glass, fluorocarbon polymers, metals (eg, chromium, tantalum), hardened sapphire, or the like, or a combination thereof. Combinations may be included, but are not limited to. As shown, the patterning of surface 112 includes features defined by a plurality of spaced apart depressions 114 and projections 116, although embodiments are not limited to such an arrangement. The patterning of surface 112 may define any original pattern upon which the pattern formed on substrate 102 is based.

The template 108 is connected to the chuck 118. Chuck 118 is typically, but not exclusively, configured as a vacuum, pin, groove, electromagnetic, or other similar chuck type. Examples of chucks are further described in US Pat. No. 6,873,087, which is incorporated herein by reference. Further, the chuck 118 can be coupled to the imprint head 120, and thus the chuck 118 and/or the imprint head 120 can be configured to facilitate movement of the template 108.

The system 100 may further include a fluid dispensing system 122. The fluid dispense system 122 may be used to deposit the imprint resist 124 on the substrate 102. The imprint resist 124 can be discharged onto the substrate 102 using a technique such as drop dispensing, spin coating, dip coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), thin film deposition, or thick film deposition. .. In the drop dispense method, as shown in FIG. 1, imprint resist 124 is disposed on substrate 102 in the form of spaced, discontinuous droplets.

The system 100 can further include an energy source 126 coupled to direct energy along the path 128. Imprint head 120 and stage 106 may be configured such that template 108 and substrate 102 are positioned over path 128. System 100 can be controlled by a processor 130 in communication with stage 106, imprint head 120, fluid dispensing system 122, and/or energy source 126 and is operated by a computer readable program stored in memory 132. be able to.

The imprint head 120 can apply a force to the template 108 so that the mold 110 contacts the imprint resist 124. After the desired amount of the imprint resist 124 is filled, energy (eg, electromagnetic radiation energy or thermal energy) is generated from the energy source 126, and the imprint resist 124 is solidified (eg, polymerized and/or crosslinked). , Conforms to the shape of surface 134 of substrate 102 and patterning surface 112. After the imprint resist 124 is solidified to obtain a polymerized layer on the substrate 102, the mold 110 is separated from the polymerized layer.

FIG. 2 shows a nanoimprint lithography laminate 200 formed by solidifying the imprint resist 124 to obtain the patterned polymer layer 202 on the substrate 102. The patterned polymer layer 202 may include a residual film 204 and a plurality of features shown as protrusions 206 and depressions 208. The thickness of the convex portion 206 is t ₁ and the thickness of the residual film 204 is t ₂ . In nanoimprint lithography, the length of one or more protrusions 206, recesses 208, or both parallel to substrate 102 is less than 100 nm, less than 50 nm, or less than 25 nm. In some cases, the length of one or more protrusions 206, recesses 208, or both is 1 nm to 25 nm or 1 nm to 10 nm.

The above system and process are described in US Pat. Nos. 6,932,934, 7,077,992, 7,197,396 and 7,396,475 (all of which are incorporated by reference). Can be further performed in an imprint lithography process and system as described herein.

In a drop-on-demand or drop-dispense nanoimprint lithography process, where imprint resist 124 as shown in FIG. 1 is placed on substrate 102 as discontinuities (“drops”), imprint resist drops typically imprint into mold 110. It spreads on the substrate 102 before and after contact with the print resist. If the drop spread of the imprint resist 124 is insufficient to cover the substrate 102 or fill the recess 114 of the mold 110, the polymerized layer 202 may be formed with defects in the form of voids. As such, the drop-on-demand nanoimprint lithography process typically begins by ejecting drops of imprint resist 124 and by moving the mold 110 toward the imprint resist on the substrate 102 between the substrate and template. There is a delay between filling the space of. As such, the throughput of automated nanoimprint lithography processes is generally limited by the spread of the imprint resist on the substrate and the rate of template filling. Therefore, the throughput of drop-on-demand or drop-dispense nanoimprint lithography processes can be improved by reducing the "fill time" (ie, the time it takes to completely fill the space between the template and the substrate without voids). it can. One way to reduce the fill time is to increase the spreading rate of the imprint resist drop and the coverage of the substrate by the imprint resist before initiating the movement of the mold towards the substrate. As described herein, the spread rate of the imprint resist and the uniformity of coating of the substrate facilitates rapid and even spread of discontinuities in the imprint resist, which may occur during formation of the patterned layer. It can be improved by pretreating the substrate with a liquid that polymerizes with the print resist.

The spread of the discontinuous portion of the second liquid on the first liquid can be understood with reference to FIGS. 3A to 3D. 3A-3D illustrate a first liquid 300 and a second liquid 302 on a substrate 304 and in contact with a gas 306 (eg, air, an inert gas such as helium or nitrogen, or a combination of inert gases). Showing. The first liquid 300 is present on the substrate 304 in the form of a coating or layer used interchangeably herein. In some cases, the first liquid 300 is present as a layer having a thickness of several nanometers (for example, 1 nm to 15 nm or 5 nm to 10 nm). The second liquid 302 is present in the form of discontinuities (“drops”). The properties of the first liquid 300 and the second liquid 302 can change with respect to each other. For example, in some cases, the first liquid 300 may be more viscous and denser than the second liquid 302.

The interface energy or surface tension between the second liquid 302 and the first liquid 300 is represented by γ _L1L2 . The interface energy between the first liquid 300 and the gas 306 is represented by γ _L1G . The interface energy between the second liquid 302 and the gas 306 is represented by γ _L2G . The interface energy between the first liquid 300 and the substrate 304 is represented by γ _SL1 . The interface energy between the second liquid 302 and the substrate 304 is represented by γ _SL2 .

FIG. 3A shows the second liquid 302 as drops placed on the first liquid 300. The second liquid 302 does not deform the first liquid 300 and does not touch the substrate 304. As shown, the first liquid 300 and the second liquid 302 are not mixed, and the interface between the first liquid and the second liquid is drawn flat. In the equilibrium state, the contact angle of the second liquid 302 on the first liquid 300 is θ, and the contact angle is Young's equation:
_{γ L1G = γ L1L2 + γ L2G} · cos (θ) (1)
Associated interfacial energy gamma _L1G, and gamma _L2G and gamma _L1L2 by.
_{γ L1G ≧ γ L1L2 + γ L2G} (2)
When θ=0°, the second liquid 302 completely spreads on the first liquid 300. If these liquids can be mixed, after some time,
γ _L1L2 =0 (3)
Becomes In this case, the conditions for the second liquid 302 to completely spread on the first liquid 300 are:
γ _L1G ≧ γ _L2G (4)
Is. For the thin film of the first liquid 300 and the droplet of the second liquid 302, the mixing can be limited by the diffusion phenomenon. Therefore, in order to spread the second liquid 302 on the first liquid 300 when the second liquid 302 is arranged in the form of drops on the first liquid 300, the inequality (2) should be calculated in the initial stage of spreading. Applicable.

FIG. 3B shows the contact angle formation for the droplet of the second liquid 302 when the underlayer of the first liquid 300 is thick. In this case, the drops do not touch the substrate 304. The drop of the second liquid 302 and the layer of the first liquid 300 intersect at angles α, β and θ,
α+β+θ=2π (5)
Is. There are three conditions for force balance at each interface:
_{γ L2G + γ L1L2 · cos (} θ) + γ L1G · cos (α) = 0 (6)
_{γ L2G · cos (θ) +} γ L1L2 + γ L1G · cos (β) = 0 (7)
_{γ L2G · cos (α) +} γ L1L2 · cos (β) + γ L1G = 0 (8)
When the first liquid 300 and the second liquid 302 can be mixed,
γ _L1L2 =0 (9)
And the formulas (6) to (8) are
_{γ L2G + γ L1G · cos (} α) = 0 (10)
_{γ L2G · cos (θ) +} γ L1G · cos (β) = 0 (11)
_{γ L2G · cos (α) +} γ L1G = 0 (12)
Becomes From equations (10) and (12),
cos ² (α)=1 (13)
And α=0, π (14)
Is given. When the second liquid 302 moistens the first liquid 300,
α=π (15)
γ _L2G = γ _L1G (16)
And by the equation (11),
cos(θ)+cos(β)=0 (17)
Is given. Combining this result with equations (5) and (15) gives
θ=0 (18)
β=π (19)
Is given. Thus, equations (15), (18) and (19) give a solution for the angles α, β and θ.
γ _L1G ≧ γ _L2G (20)
, No equilibrium between the interfaces occurs. Equation (12) becomes an inequality even if α=π, and the second liquid 302 continues to spread on the first liquid 300.

FIG. 3C shows a more complex geometry for a drop of the second liquid 302 that also holds the interface with the first liquid 300 while touching the substrate 304. The interface region between the first liquid 300, the second liquid 302 and the gas 306 (defined by the angles α, β and θ ₁ ) and the interface region between the first liquid 300, the second liquid 302 and the substrate 304 (by θ ₂ Defined) must be considered in determining the spreading behavior of the second liquid on the first liquid.

The interface region between the first liquid 300, the second liquid 302, and the gas 306 is governed by the equations (6) to (8). Since the first liquid 300 and the second liquid 302 can be mixed,
γ _L1L2 =0 (21)
Becomes The solution for the angle α is given by equation (14). in this case,
α=0 (22)
And θ ₁ =π (23)
β=π (24)
Becomes
γ _L1G ≧ γ _L2G (25)
, The droplet of the second liquid 302 and the first liquid 300 do not equilibrate with each other and the second liquid and the gas until limited by other physical restrictions (eg volume preservation and mixing). Drops continue to spread along the interface between.

For the interface region between the first liquid 300, the second liquid 302, and the substrate 304, the same formula as the formula (1):
γ _SL1 =γ _SL2 +γ _{L1 L2} ·cos(θ ₂ ) (26)
think of.
γ _SL1 ≧γ _SL2 +γ _L1L2 (27)
, The drop is completely spread out and θ ₂ =0. Furthermore, for liquids that can be mixed, the second term γ _L1L2 =0, and the inequality (27) becomes
γ _SL1 ≧γ _SL2 (28)
Simplified to. Considering the energy before and after the spread, the compound condition about the spread of the liquid is
_{γ L1G + γ SL1 ≧ γ L2G} + γ SL2 (29)
Is expressed as An energetically dominant transition (ie, a transition that minimizes the energy of the system) shall occur.

From the different relationships between the four terms in inequality (29), the drop spreading properties are determined. When the inequality (25) is valid and the inequality (28) is not valid, the droplet of the second liquid 302 can first spread along the surface of the first liquid 300. Alternatively, if the inequality (28) is retained and the inequality (25) is not retained, the drop may begin to spread along the liquid-solid interface. Ultimately, the first liquid 300 and the second liquid 302 are mixed, which introduces greater complexity.

FIG. 3D shows the geometry for a drop of the second liquid 302 that also holds the interface with the first liquid 300 while touching the substrate 304. As shown in FIG. 3D, there are two target interface regions on each side of the drop of the second liquid 302. The first interface region is where the first liquid 300, the second liquid 302, and the gas 306 contact each other, which are indicated by angles α, β, and θ ₁ . The target second interface region is a place where the first liquid 300, the second liquid 302, and the substrate 304 contact each other, which is indicated by an angle θ ₂ . Here, when the surface tension of the interface between the second liquid 302 and the substrate 304 is larger than the surface tension of the interface between the first liquid 300 and the substrate (γ _SL2 ≧γ _SL1 ), θ ₁ becomes 0 degree as the droplet spreads. And θ ₂ approaches 180 degrees. That is, the droplet of the second liquid 302 spreads along the interface between the first liquid 300 and the second liquid, and does not spread along the interface between the second liquid and the substrate 304.

Equations (6) to (8) can be applied to the interface between the first liquid 300, the second liquid 302, and the gas 306. Since the first liquid 300 and the second liquid 302 can be mixed,
γ _L1L2 =0 (30)
Becomes The solution for the angle α is given by equation (14).
α=π (31)
Then, according to equation (11),
cos(θ ₁ )+cos(β)=0 (32)
And θ ₁ =0 (33)
β=π (34)
Is given.
γ _L1G ≧ γ _L2G (35)
If there is no equilibrium between the drops of the second liquid 302 and the liquid 300, and between the second liquid and the gas until limited by other physical restrictions (eg volume preservation and mixing). Drops continue to spread along the interface.

In the interface region between the second liquid 302 and the substrate 304,
γ _SL1 =γ _SL2 +γ _{L1 L2} ·cos(θ ₂ ) (36)
cos(θ ₂ )=(γ _SL1 −γ _SL2 )/γ _L1L2 (37)
Becomes
γ _SL1 ≦γ _SL2 (38)
And if the liquids can be mixed, that is,
γ _L1L2 → 0 (39)
−∞≦cos(θ ₂ )≦−1 (40)
, The angle θ ₂ is undecided after approaching 180 degrees. That is, the second liquid 302 tends to shrink along the interface of the substrate and spread along the interface between the first liquid 300 and the gas 306.

The spread of the second liquid 302 on the first liquid 300 can be summarized in three different cases, along with the surface energy relationship for full spread. In the first case, a drop of the second liquid 302 is placed on the layer of the first liquid 300 and the drop of the second liquid is not in contact with the substrate 304. The layer of the first liquid 300 may be thick or thin, and the first liquid 300 and the second liquid 302 can be mixed. In ideal conditions, when the surface energy of the first fluid 300 in the gas 306 is above the surface energy of the second liquid 302 in the gas _{306 (γ L1G ≧ γ L2G)} , full of droplets of the second liquid 302 Spreading occurs on the layer of the first liquid 300. In the second case, a drop of the second liquid 302 is being placed on the layer of the first liquid 300 and at the same time touching and spreading on the substrate 304. The first liquid 300 and the second liquid 302 can be mixed. In ideal conditions, (i) the surface energy of the first fluid 300 in the gas is not less than the surface energy of the second liquid 302 in the gas _{(γ L1G ≧ γ L2G),} (ii) the first liquid and the substrate Complete spreading occurs when the surface energy at the interface with 304 is greater than the surface energy at the interface between the second liquid and the substrate (γ _SL1 ≧γ _SL2 ). In the third case, a drop of the second liquid 302 is placed on the layer of the first liquid 300 while touching the substrate 304. The spreading can occur along the interface between the second liquid 302 and the first liquid 300 or the interface between the second liquid and the substrate 304. The first liquid and the second liquid 302 can be mixed. Under ideal conditions, the sum of the surface energy of the first liquid 300 in the gas and the surface energy of the interface between the first liquid and the substrate 304 is the surface energy of the second liquid 302 in the gas and the second liquid 302. surfactant is greater than or equal to the sum of the surface energy of the _{(γ L1G + γ SL1 ≧ γ} L2G + γ SL2), the surface energy of the first fluid 300 in the gas is at least the surface energy of the second liquid 302 in the gas between the substrate and the or (γ _L1G ≧ γ _L2G), or (ii) the surface energy of the interface between the first liquid and the substrate 304 is complete is greater than the surface energy of the interface between the second liquid and the substrate _{(γ SL1} ≧ γ _SL2) Spread occurs.

In a drop-on-demand nanoimprint lithography process, by pretreating the nanoimprint lithography substrate with a liquid whose surface energy is selected to be greater than that of the imprint resist in an ambient atmosphere (eg, air or an inert gas). The speed at which the imprint resist spreads on the substrate can be increased, and a more uniform thickness of the imprint resist on the substrate can be ensured before contacting the imprint resist with the template, thereby nanoimprinting. Throughput in the lithographic process is enhanced. If the pretreatment composition contains a polymerizable component that is miscible with the imprint resist, this beneficially contributes to the formation of the resulting polymerized layer without the addition of unwanted components and results in a more uniform Due to the curing, more uniform mechanical and etching properties can be obtained.

FIG. 4 is a flow chart diagram illustrating a process 400 for promoting throughput in drop-on-demand nanoimprint lithography. Process 400 includes operations 402-410. In operation 402, the pretreatment composition is placed on the nanoimprint lithography substrate to form a pretreatment coating on the substrate. In operation 404, a discontinuous portion (“drop”) of imprint resist is placed on the pretreatment coating, each drop covering a target area of the substrate. The pretreatment composition and the imprint resist are selected so that the interfacial energy between the pretreatment composition and air is larger than the interfacial energy between the imprint resist and air.

In operation 406, each drop of imprint resist extends beyond its target area to form a composite polymerizable coating (“composite coating”) on the substrate. The composite coating includes a homogeneous or heterogeneous mixture of pretreatment composition and imprint resist. At operation 408, the composite coating is contacted with a nanoimprint lithography template (“template”), spread out, and fills the entire volume between the template and the substrate. At operation 410, the composite coating is polymerized to obtain a polymerized layer on the substrate. After polymerization of the composite coating, the template is separated from the polymerized layer into a nanoimprint lithography laminate. As used herein, "nanoimprint lithographic laminate" generally refers to a substrate and a polymeric layer that adheres to the substrate, each or both of which may comprise one or more additional (eg, intervening) layers. May be included. In one example, the substrate can include a base layer and an adhesion layer that adheres to the base layer.

In process 400, the pretreatment composition and imprint resist are provided, for example, in U.S. Patent No. 7,157,036 and U.S. Patent No. 8,076,386, and Chou et al. 1995, Imprint of sub-25 nm vias and. Trenches in polymers. Applied Physics Letters 67(21):3114-3116, Chou et al. 1996, Nanoimprint lithography. Journal of Vacuum Science Technology B 14(6): 4129-4133, and Long et al. 2007, Materials for step. and flash imprint lithography (S-FIL™). Journal of Materials Chemistry 17:3575-3580, which are incorporated herein by reference and include mixtures of the components described therein. Good. Suitable compositions include polymerizable monomers (“monomers”), crosslinkers, resins, photoinitiators, surfactants, or any combination thereof. Types of monomers include acrylates, methacrylates, vinyl ethers and epoxides, and their polyfunctional derivatives. In some cases, the pretreatment composition, the imprint resist, or both are substantially free of silicon. In other cases, the pretreatment composition, the imprint resist, or both contain silicon. Examples of the silicon-containing monomer include siloxane and disiloxane. The resin can be silicon-containing (eg, silsesquioxane) and silicon-free (eg, novolac resin). The pretreatment composition, the imprint resist, or both may include one or more polymerization initiators or free radical generators. Examples of the type of the polymerization initiator include a photopolymerization initiator (for example, acyloin, xanthone and phenone), a photoacid generator (for example, sulfonate and onium salt), and a photobase generator (for example, ortho-nitrobenzyl). Carbamates, oxime urethanes and O-acyl oximes).

Suitable monomers include monofunctional, difunctional or polyfunctional acrylates, methacrylates, vinyl ethers and epoxides, where mono-, di- and poly- each have one designated functional group, Refers to two and three or more. Some or all of the monomers may be fluorinated (eg, perfluorinated). In the case of acrylates, for example, the pretreatment composition, the imprint resist or both may comprise one or more monofunctional acrylates, one or more difunctional acrylates, one or more multifunctional acrylates, or a combination thereof. Combinations may be included.

Examples of suitable monofunctional acrylates include isobornyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, dicyclopentenyl acrylate, benzyl acrylate, 1-naphthyl acrylate, 4-cyanobenzyl acrylate, pentafluorobenzyl acrylate, 2-phenylethyl acrylate, phenyl acrylate, (2-ethyl-2-methyl-1,3-dioxolan-4-yl)methyl acrylate, n-hexyl acrylate, 4-tert-butylcyclohexyl acrylate, methoxypolyethylene glycol (350) Mention may be made of monoacrylate and methoxypolyethylene glycol (550) monoacrylate.

Examples of suitable diacrylates include ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate (eg, average Mn=575), 1,2-propanediol diacrylate. Acrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 1,3-propanediol diacrylate, 1,4-butanediol diacrylate, 2-butene-1,4-diacrylate, 1, 3-butylene glycol diacrylate, 3-methyl-1,3-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, 1H,1H,6H,6H-perfluoro-1, 6-hexanediol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, 1,12-dodecanediol diacrylate, neopentyl glycol diacrylate, cyclohexanedimethanol diacrylate, tricyclodecane diacrylate Methanol diacrylate, bisphenol A diacrylate, ethoxylated bisphenol A diacrylate, m-xylylene diacrylate, ethoxylated (3) bisphenol A diacrylate, ethoxylated (4) bisphenol A diacrylate, ethoxylated (10) bisphenol A diacrylate Acrylate, dicyclopentanyl diacrylate, 1,2-adamantanediol diacrylate, 2,4-diethylpentane-1,5-diol diacrylate, poly(ethylene glycol)(400) diacrylate, poly(ethylene glycol)( 300) diacrylate, 1,6-hexanediol (EO) ₂ diacrylate, 1,6-hexanediol (EO) ₅ diacrylate and alkoxylated aliphatic diacrylate ester.

Examples of suitable multifunctional acrylates include trimethylol propane triacrylate, propoxylated trimethylol propane triacrylate (eg propoxylated (3) trimethylol propane triacrylate, propoxylated (6) trimethylol propane triacrylate). Acrylate), trimethylolpropane ethoxylate triacrylate (eg, n to about 1.3, 3, 5, 5), di(trimethylolpropane) tetraacrylate, propoxylated glyceryl triacrylate (eg, propoxylated (3) glyceryl). Triacrylate), tris(2-hydroxyethyl)isocyanurate triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ethoxylated pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, tripentaerythritol octaacrylate.

Examples of suitable crosslinkers include difunctional acrylates and polyfunctional acrylates as described herein.
The photopolymerization initiator is preferably a radical generator, and examples of the radical generator include 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer and 2-(o-chlorophenyl)-4,5. -Di(methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o- or p-methoxyphenyl)-4,5-diphenylimidazole dimer 2,4,5-triarylimidazole dimer which may have a substituent such as benzophenone, N,N'-tetramethyl-4,4'-diaminobenzophenone (Michler's ketone), N,N'- Benzophenone derivatives such as tetraethyl-4,4'-diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone; 2-benzyl- Α-Amino aromatic such as 2-dimethylamino-1-(4-morpholinophenyl)-butanone-1,2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one Ketone derivative; 2-ethylanthraquinone, phenanthrenequinone, 2-t-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 2,3-benzanthraquinone, 2-phenylanthraquinone, 2,3-diphenylanthraquinone, 1- Quinones such as chloroanthraquinone, 2-methylanthraquinone, 1,4-naphthoquinone, 9,10-phenantharaquinone, 2-methyl-1,4-naphthoquinone and 2,3-dimethylanthraquinone; benzoin methyl ether, benzoin ethyl ether Benzoin ether derivatives such as benzoin phenyl ether; Benzoin derivatives such as benzoin, methylbenzoin, ethylbenzoin, propylbenzoin; Benzyl derivatives such as benzyldimethylketal; 9-phenylacridine, 1,7-bis(9,9′-acridinyl) ) Acridine derivatives such as heptane; N-phenylglycine derivatives such as N-phenylglycine; acetophenone, 3-methylacetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, acetophenone such as 2,2-dimethoxy-2-phenylacetophenone. Derivatives: thioxanthone, diethylthioxanthone, 2-isopropylthioki Thioxanthone derivatives such as Sandton and 2-chlorothioxanthone; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)- Acylphosphine oxide derivatives such as 2,4,4-trimethylpentylphosphine oxide; 1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyloxime)], ethanone, 1- Oxime ester derivatives such as [9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-,1-(O-acetyloxime); xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenyl. Examples thereof include amine, carbazole, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one. There is no limitation.

As a commercial item of the said radical generator, Irgacure 184, 369, 651, 500, 819, 907, 784, 2959, CGI-1700, -1750, -1850, CG24-61, Darocur 1116, 1173, Lucirin TPO, LR8893, LR8970. (Above, manufactured by BASF), Yubecryl P36 (manufactured by UCB) and the like, but not limited thereto.

It is preferably an acylphosphine oxide-based polymerization initiator or an alkylphenone-based polymerization initiator. Among the above examples, the acylphosphine oxide-based polymerization initiators are 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and bis(2,6). -Dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide and other acylphosphine oxide compounds. Further, among the above examples, the alkylphenone-based polymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin phenyl ether, and other benzoin ether derivatives; benzoin, methylbenzoin, ethylbenzoin, propylbenzoin, and other benzoin derivatives; benzyldimethyl. Benzyl derivatives such as ketals; acetophenone, 3-methylacetophenone, acetophenone benzyl ketals, 1-hydroxycyclohexylphenyl ketone, acetophenone derivatives such as 2,2-dimethoxy-2-phenylacetophenone; 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl)-butanone-1,2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one and other α-amino aromatic ketone derivatives.

The mixing ratio of the photopolymerization initiator is 0.1% by weight or more and 50% by weight or less, preferably 0.1% by weight or more and 20% by weight or less, based on the total weight of all components excluding the solvent component. More preferably, it is more than 10% by weight and 20% by weight or less.

The pretreatment composition and the imprint resist are curable compositions. Hereinafter, the pretreatment composition and the imprint resist are referred to as a curable composition.

When the content is 0.1% by weight or more based on the total weight excluding the solvent component, the curing rate of the curable composition can be increased. As a result, the reaction efficiency can be improved. Further, when the content is 50% by weight or less based on the total weight excluding the solvent component, the obtained cured product can be a cured product having a mechanical strength to some extent.

Examples of suitable photopolymerization initiators include IRGACURE 907, IRGACURE 4265, 651, 1173, 819, TPO and TPO-L.

The surfactant is applied to the patterned surface of the imprint lithography template, added to the imprint lithography resist, or both to reduce the separation force between the solidified resist and the template, thereby imprinting the imprint lithography template. Separation defects in the imprint pattern formed in the lithographic process can be reduced and the number of consecutive imprints that can be made using the imprint lithographic template can be increased. Factors in selecting a release agent for an imprint resist include affinity with the surface, desired surface characteristics of the treated surface, and life of the release agent in the imprint resist. Some exfoliants form covalent bonds with the template, while nonionic fluorinated surfactants interact with the template surface via noncovalent interactions such as hydrogen bonding and van der Waals interactions. ..

Examples of suitable surfactants include fluorinated and non-fluorinated surfactants. The fluorinated surfactant and the non-fluorinated surfactant may be an ionic surfactant or a nonionic surfactant. Suitable nonionic fluorinated surfactants include fluoroaliphatic polymer esters, perfluoroether surfactants, polyoxyethylene fluorosurfactants, polyalkyl ether fluorosurfactants, fluoroalkyl polyethers. Etc. Suitable nonionic non-fluorinated surfactants include ethoxylated alcohols, ethoxylated alkylphenols and polyethylene oxide-polypropylene oxide block copolymers.

Exemplary commercially available surfactant ingredients include ZONYL™ FSO and ZONYL™ FS-300 from EI du Pont de Nemours and Company, Wilmington, Del.; 3M from Maplewood, Minnesota. FC-4432 and FC-4430; MASURF™ FS-1700, FS-2000 and FS-2800 from Pilot Chemical Company of Cincinnati, Ohio; S-107B from Chemguard of Mansfield, Texas; FTERGENT 222F, FTERGENT 250, FTERGENT 251 manufactured by Chuo-ku, Kobe, Japan; PolyFox PF-656 manufactured by OMNOVA Solutions Inc., Akron, Ohio; Pluronic L35, L42, L43 manufactured by BASF, Florum Park, NJ. L44, L63, L64 and the like; Brij 35, 58, 78 and the like manufactured by Croda Inc. of Edison, NJ, but are not limited thereto.

(Other ingredients)
In addition to the components described above, the pretreatment composition and the imprint resist may contain a non-polymerizable compound according to various purposes within a range not impairing the effects of the present invention. Examples of such components include sensitizers, hydrogen donors, antioxidants, polymer components, and other additives.

The sensitizer is a compound that is appropriately added for the purpose of promoting the polymerization reaction and improving the reaction conversion rate. Examples of the sensitizer include sensitizing dyes.

The sensitizing dye is a compound that is excited by absorbing light having a specific wavelength and interacts with the photopolymerization initiator that is the component (B). The interaction described here means energy transfer or electron transfer from the sensitizing dye in the excited state to the photopolymerization initiator which is the component (B).

Specific examples of the sensitizing dyes include anthracene derivatives, anthraquinone derivatives, pyrene derivatives, perylene derivatives, carbazole derivatives, benzophenone derivatives, thioxanthone derivatives, xanthone derivatives, coumarin derivatives, phenothiazine derivatives, camfaquinone derivatives, acridine dyes, thiopyrylium salt dyes. Dyes, merocyanine dyes, quinoline dyes, styrylquinoline dyes, ketocoumarin dyes, thioxanthene dyes, xanthene dyes, oxonol dyes, cyanine dyes, rhodamine dyes, pyrylium salt dyes, and the like. It is not limited to these.
As the sensitizer, one kind may be used alone, or two or more kinds may be mixed and used.

The hydrogen donor is a compound that reacts with an initiation radical generated from the photopolymerization initiator that is the component (B) or a radical at the polymerization growth terminal to generate a radical having higher reactivity. The hydrogen donor is preferably added when the component (B) is a photoradical generator.

Specific examples of such a hydrogen donor include n-butylamine, di-n-butylamine, tri-n-butylamine, allylthiourea, s-benzylisothiuronium-p-toluenesulfinate, triethylamine, diethylaminoethylmethacrylate. , Triethylenetetramine, 4,4'-bis(dialkylamino)benzophenone, N,N-dimethylaminobenzoic acid ethyl ester, N,N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethanolamine , Amine compounds such as N-phenylglycine, and mercapto compounds such as 2-mercapto-N-phenylbenzimidazole and mercaptopropionate, but are not limited thereto.

As the hydrogen donor, one kind may be used alone, or two or more kinds may be mixed and used. Further, the hydrogen donor may have a function as a sensitizer.

The compounding ratio of the above-mentioned non-polymerizable compound in the curable composition is 0% by weight or more and 50% by weight or less, preferably 0.1% by weight or more, based on the total weight of all components excluding the solvent component. It is 50% by weight or less, and more preferably 0.1% by weight or more and 20% by weight or less.

(About solvent)
Further, the pretreatment composition and the imprint resist may contain a solvent as a component. Although not particularly limited, a preferable solvent is a solvent having a boiling point of 80° C. or higher and 200° C. or lower at normal pressure. More preferably, it is a solvent having at least one of a hydroxyl group, an ether structure, an ester structure and a ketone structure.

Specific examples of the solvent include alcohol solvents such as propyl alcohol, isopropyl alcohol and butyl alcohol; ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monobutyl ether, propylene glycol. Ether-based solvents such as monomethyl ether; butyl acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, ester-based solvents such as propylene glycol monomethyl ether acetate; methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, 2-heptanone, γ- A single solvent selected from ketone solvents such as butyrolactone and ethyl lactate, or a mixed solvent thereof is preferable.

In particular, the pretreatment composition preferably contains a solvent. This is because the spin coating method is preferable as the coating method on the substrate, as will be described later.

In this case, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, cyclohexanone, 2-heptanone, γ-butyrolactone, ethyl lactate, or a mixed solution thereof is particularly preferable from the viewpoint of coating property.

The blending ratio of the solvent component in the pretreatment composition can be appropriately adjusted depending on the viscosity, coatability, film thickness of the formed cured layer and the like, but is preferably 70% by mass or more based on the total amount of the pretreatment composition. It is more preferably 90% by mass or more, and further preferably 95% by mass or more. The more the solvent component is, the thinner the cured layer formed can be made. When the blending ratio of the solvent component in the pretreatment composition is less than 70% by mass, sufficient coatability may not be obtained.

Although a solvent can be used for the imprint resist, it is preferable that the imprint resist contains substantially no solvent. Here, "substantially free of solvent" means that it does not include a solvent other than the solvent that is unintentionally included such as impurities. That is, for example, the content of the solvent in the imprint resist according to this embodiment is preferably 3% by weight or less, and more preferably 1% by weight or less, based on the entire imprint resist. The term "solvent" as used herein refers to a solvent or a solvent that is generally used in curable compositions and photoresists. That is, the kind of the solvent is not particularly limited as long as it dissolves and uniformly disperses the compound used in the present invention and does not react with the compound.

In some examples, the imprint resist comprises 0 wt% to 80 wt% (eg, 20 wt% to 80 wt% or 40 wt% to 80 wt%) of one or more monofunctional acrylates, and % To 98% by weight of one or more difunctional or multifunctional acrylates (eg, the imprint resist may be substantially free of monofunctional acrylate) or 20% to 75% by weight. % Of one or more difunctional or multifunctional acrylates (eg, where one or more monofunctional acrylates are present) and 1% to 10% by weight of one or more photoinitiators. And 1% to 10% by weight of one or more surfactants. In one example, the imprint resist comprises about 40% to about 50% by weight of one or more monofunctional acrylates and about 45% to about 55% by weight of one or more difunctional acrylates. Includes about 4% to about 6% by weight of one or more photoinitiators and about 3% by weight of surfactant. In another example, the imprint resist comprises about 44% by weight of one or more monofunctional acrylates, about 48% by weight of one or more difunctional acrylates, and about 5% by weight of one or more. It includes a plurality of photopolymerization initiators and about 3% by weight of a surfactant. In yet another example, the imprint resist comprises about 10% by weight of a first monofunctional acrylate (eg, isobornyl acrylate) and about 34% by weight of a second monofunctional acrylate (eg, benzyl acrylate). ), about 48% by weight of a difunctional acrylate (eg, neopentyl glycol diacrylate), about 2% by weight of a first photoinitiator (eg, IRGACURE TPO), and about 3% by weight of a second. Of a photoinitiator (eg, DAROCUR 4265) and about 3% by weight of a surfactant. Examples of suitable surfactants are X—R—(OCH ₂ CH ₂ ) _n OH, where R=alkyl, aryl or poly(propylene glycol), X═H or —(OCH ₂ CH ₂ ) and _n OH, n is (for example, 2～20,5～15 or 10 to 12) _{(e.g., X = - (OCH 2 CH} 2) integer is n OH, R = poly (propylene glycol) And n=10 to 12)), a fluorosurfactant (where X=perfluorinated alkyl or perfluorinated ether), or a combination thereof. The viscosity of the imprint resist is usually 0.1 cP to 25 cP or 5 cP to 15 cP at 23°C. The interface energy between the imprint resist and air is usually 20 mN/m to 36 mN/m.

In one example, the pretreatment composition comprises 0 wt% to 80 wt% (eg, 20 wt% to 80 wt% or 40 wt% to 80 wt%) one or more monofunctional acrylates and 90 wt%. To 100% by weight of one or more difunctional or multifunctional acrylates (eg, the pretreatment composition is substantially free of monofunctional acrylate) or 20% to 75% by weight of one or more. A difunctional or polyfunctional acrylate (for example when one or more monofunctional acrylates are present), 0% to 10% by weight of one or more photoinitiators, and 0% by weight. -10% by weight of one or more surfactants.

The pretreatment composition is typically compatible with the imprint resist. The pretreatment composition typically has a low vapor pressure so that it remains as a thin film on the substrate until the composite coating is polymerized. In one example, the vapor pressure of the pretreatment composition is less than 1×10 ⁻⁴ mmHg at 25° C. The pretreatment composition also typically has a low viscosity, facilitating rapid spread of the pretreatment composition on the substrate. In one example, the viscosity of the pretreatment composition is less than 90 cP at 25°C. The interfacial energy between the pretreatment composition and air is typically 30 mN/m to 45 mN/m. The pretreatment composition is typically selected so that it does not decompose during use and is chemically stable.

(Impurities mixed in the curable composition)
The pretreatment composition and the imprint resist are preferably as free from impurities as possible. The impurities described here mean those other than the above-mentioned components. Therefore, it is preferable that the pretreatment composition and the imprint resist are obtained through a purification process. As such a purification step, filtration using a filter or the like is preferable. When performing filtration using a filter, specifically, after mixing the components described above and additional components to be added as necessary, for example, filter with a filter having a pore size of 0.001 μm or more and 5.0 μm or less. Is preferred. When performing filtration using a filter, it is more preferable to perform the filtration in multiple stages or repeat it many times. Further, the filtered liquid may be filtered again. You may filter using a several filter with a different hole diameter. As the filter used for filtration, a filter made of polyethylene resin, polypropylene resin, fluororesin, nylon resin, or the like can be used, but the filter is not particularly limited. Through such a refining step, impurities such as particles mixed in the composition can be removed. This can prevent impurities such as particles from causing careless unevenness in the cured film obtained after curing the curable composition and causing pattern defects.

When the pretreatment composition and the imprint resist are used for manufacturing a semiconductor integrated circuit, impurities (metal impurities) containing a metal atom are contained in the curable composition so as not to hinder the operation of the product. ) It is preferable to avoid as much as possible. In such a case, the concentration of metal impurities contained in the curable composition is preferably 10 ppm or less, more preferably 100 ppb or less.

The pretreatment composition comprises a single polymerizable component (eg, a monomer such as a monofunctional acrylate, a difunctional acrylate or a polyfunctional acrylate), a mixture of two or more polymerizable components (eg, two). Or a mixture of one or more polymerizable components and one or more other components (for example, a mixture of monomers; two or more monomers and a surfactant). , A photopolymerization initiator, or a mixture thereof, etc.). In some examples, the pretreatment composition includes trimethylolpropane triacrylate, trimethylolpropane ethoxylate triacrylate, 1,12-dodecanediol diacrylate, poly(ethylene glycol) diacrylate, tetraethylene glycol diacrylate, 1,3-adamantane diol diacrylate, nonane diol diacrylate, m-xylylene diacrylate, dicyclopentanyl diacrylate or any combination thereof.

A pretreatment composition in which a mixture of polymerizable components produces a synergistic effect and has beneficial properties (eg, low viscosity, good etch resistance and film stability) over pretreatment compositions containing a single polymerizable component. May be obtained. In one example, the pretreatment composition is a mixture of 1,12-dodecanediol diacrylate and tricyclodecane dimethanol diacrylate. In another example, the pretreatment composition is a mixture of tricyclodecane dimethanol diacrylate and tetraethylene glycol diacrylate. The pretreatment composition is generally such that during polymerization of the composite polymerizable coating, one or more components of the pretreatment composition polymerize (eg, covalently bond) with one or more components of the imprint resist. Selected. In some cases, the pretreatment composition comprises the same polymerizable component as the imprint resist or a polymerizable component having a functional group (eg, an acrylate group) in common with one or more polymerizable components of the imprint resist. Suitable examples of pretreatment compositions include propoxylated (3) trimethylolpropane triacrylate, trimethylolpropane triacrylate and dipentaerythritol pentaacrylate, a multifunctional acrylate as described herein. Are listed.

The pretreatment composition can be selected such that the etch resistance is about the same as the etch resistance of the imprint resist, thereby promoting etch uniformity. In some cases, the pretreatment composition provides that the interfacial energy at the interface between the pretreatment composition and air is greater than the interfacial energy between the imprint resist and air used with the pretreatment composition. , Is selected to promote rapid spreading of the liquid imprint resist on the liquid pretreatment composition and to form a uniform composite coating on the substrate prior to contacting the composite coating with the template. The interfacial energy between the pretreatment composition and air is typically between 1 mN/m and 25 mN/m more than the interfacial energy between the imprint resist and air or between at least one component of the imprint resist and air, 1 mN/m to 15 mN/m or 1 mN/m to 7 mN/m greater, but these ranges are dependent on the chemical and physical properties of the pretreatment composition and imprint resist, and the interrelationship obtained between these two liquids. It can vary based on the action. If the surface energy difference is too small, the spread of the imprint resist will be limited and the droplets will retain their spherical cap shape and remain separated by the pretreatment composition. If the difference between the surface energies is too large, the imprint resist will spread out too much and most of the imprint resist will move towards the adjacent drop, causing the drop center to empty, which will cause the composite coating to overhang the drop center. It will have a convex region. Therefore, if the difference between the surface energies is too small or too large, the resulting composite coating will be non-uniform with significant uneven areas. With the proper choice of surface energy differences, the imprint resist spreads rapidly resulting in a substantially uniform composite coating. Beneficial choice of pretreatment composition and imprint resist allows to shorten the filling time by 50% to 90%, so that the filling can be as short as 1 second or even less than 0.1 seconds in some cases. Can be achieved with.

Referring to operation 402 of process 400, FIG. 5A illustrates substrate 102 with base layer 500 and adhesion layer 502. The base layer 500 is typically a silicon wafer. Other suitable materials for the base layer 500 include fused quartz, quartz, silicon germanium, gallium arsenide and indium phosphide. The adhesion layer 502 has a function of improving adhesion between the polymer layer and the base layer 500 to reduce formation of defects in the polymer layer when the template is separated from the polymer layer after the composite coating is polymerized. The thickness of the adhesion layer 502 is usually 1 nm to 10 nm. Examples of materials suitable for the adhesion layer 502 include U.S. Patent Nos. 7,759,407, 8,361,546, 8,557,351, 8,808,808, and Nos. 8,846,195, which are incorporated herein by reference in their entirety. In one example, the adhesion layer is ISORAD 501, CYMEL 303ULF, CYCAT 4040 or TAG 2678 (trifluoromethanesulfonic acid blocked by quaternary ammonium) and PM acetate (2-(manufactured by Eastman Chemical Company, Kingsport, TN). And a solvent consisting of 1-methoxy)propylacetate). In some cases, the substrate 102 comprises one or more additional layers between the base layer 500 and the adhesion layer 502. In some cases, the substrate 102 comprises one or more additional layers on the adhesion layer 502. For simplicity, substrate 102 is shown as having only base layer 500 and adhesion layer 502.

FIG. 5B shows pretreatment composition 504 after the pretreatment composition has been placed on substrate 102 and pretreatment coating 506 has been formed. The pretreatment coating 506 is formed directly on the adhesion layer 502 of the substrate 102, as shown in FIG. 5B. In some cases, pretreatment coating 506 is formed on another surface of substrate 102 (eg, directly on base layer 500). The pretreatment coating 506 is formed on the substrate 102 using a technique such as spin coating, dip coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), or the like. For example, in the case of spin coating or dip coating, etc., the pretreatment composition is dissolved in one or more solvents (eg, propylene glycol methyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), etc.), After application to the substrate, evaporation of the solvent can leave the pretreatment coating. The thickness _{t p} of the pretreatment coating 506 is typically, 1 nm~100 nm (e.g., 1nm~50nm, 1nm~25nm or 1 nm to 10 nm).

Still referring to FIG. 4, operation 404 of process 400 includes placing the imprint resist drops on the pretreatment coating such that each drop of the imprint resist covers a target area of the substrate. The volume of the imprint resist droplet is typically 0.6 pL to 30 pL, and the distance between the centers of the droplets is typically 35 μm to 350 μm. In some cases, the volume ratio of imprint resist to pretreatment coating is 1:1 to 15:1. In operation 406, a composite coating is formed on the substrate such that each drop of imprint resist extends beyond its target area to form the composite coating. As used herein, "prespreading" occurs between the time when the drop first contacts the pretreatment coating and spreads beyond the target area and the time when the template contacts the composite coating. Refers to the natural spread of imprint resist drops.

6A-6D show imprinted resist drops on the pretreatment coating at the time the drop is placed on the target area, and the composite coating before, during, and after the drop spreads. The figure which looked at from above is shown. Although the drops are shown in a square grid, the drop pattern is not limited to a square or geometric pattern.

FIG. 6A shows a top view of drop 600 on pretreatment coating 506 at the time the drop is first placed on the pretreatment coating such that the drop covers target area 602, but does not spread beyond target area 602. Figure shown. After the drop 600 is placed on the pretreatment coating 506, the drop naturally spreads to cover the surface area of the substrate that is larger than the target area, forming a composite coating on the substrate. FIG. 6B shows a top-down view of the composite coating 604 after some mixing of the imprint resist and pretreatment coating, typically during pre-spreading (after some spread of the drop 600 beyond the target area 602 ). .. As shown, the composite coating 604 is a mixture of a liquid pretreatment composition and a liquid imprint resist, and regions 606 contain the majority of the imprint resist (“rich in imprint resist”). 608 contains the majority of the pretreatment composition (“rich in pretreatment composition”). As the pre-spreading progresses, the composite coating 604 can form a more homogenous mixture of the pretreatment composition and the imprint resist.

Spreading can proceed until one or more regions 606 contact one or more adjacent regions 606. 6C and 6D show the composite coating 604 after it has been fully spread. As shown in FIG. 6C, each of the regions 606 extends so as to contact the adjacent regions 606 at boundaries 610, and the regions 608 are reduced to the discontinuous (non-continuous) portion between the regions 606. In other cases, as shown in FIG. 6D, the region 606 has expanded to form a continuous layer such that the region 608 is indistinguishable. In FIG. 6D, the composite coating 604 can be a homogenous mixture of pretreatment composition and imprint resist.

7A to 7D are cross-sectional views taken along lines w-w, xx, yy and z-z of FIGS. 6A to 6D. FIG. 7A is a cross-sectional view along line ww of FIG. 6A showing a drop 600 of imprint resist covering the surface area of substrate 102 corresponding to target area 602. Each target area (and each drop that was initially placed) has a center, as indicated by the cc line, and the bb line indicates positions equally spaced from the centers of the two target areas 602. For simplicity, the drop 600 is shown to contact the adhesion layer 502 of the substrate 102, and the imprint resist and pretreatment composition admixture is not shown. FIG. 7B is a cross-sectional view along line xx of FIG. 6B showing composite coating 604 with regions 606 exposed between regions 608 after regions 606 extend beyond target region 602. FIG. 7C is a cross-sectional view along line yy of FIG. 6C at the end of pre-spreading, showing the composite coating 604 as a homogeneous mixture of the pretreatment composition and the imprint resist. As shown, region 606 has expanded to cover a wider substrate surface than in FIG. 7B, and region 608 has shrunk accordingly. Although the regions 606 based on the drops 600 are shown as convex, the composite coating 604 may be generally flat or may include concave regions. In some cases, the imprint resist may form a continuous layer on the pretreatment coating (premixed or unmixed or wholly or partially), followed by pre-spreading beyond that shown in FIG. 7C. Mix). FIG. 7D is a cross-sectional view along line zz of FIG. 6D showing the composite coating 604 as a homogenous mixture of the post-spread pretreatment composition and imprint resist, with respect to the drop center c-c. The recessed areas of the composite coating are in contact with each other at the boundary 610, so that the thickness of the polymerized coating at the drop boundary is greater than the thickness of the composite coating at the center of the drop. As shown in FIGS. 7C and 7D, when the composite coating is contacted with the nanoimprint lithography template, the thickness of the composite coating 604, which is evenly spaced from the centers of the two target areas, is the center of one of the two target areas. The thickness of the composite coating can be different.

Still referring to FIG. 4, operations 408 and 410 of process 400 contact the composite coating with the template and polymerize the composite coating to obtain a nanoimprint lithographic laminate comprising the composite polymeric layer on the nanoimprint lithographic substrate. Including each.

In some cases, as shown in FIGS. 7C and 7D, the composite coating 604 may be a homogeneous or substantially homogeneous mixture at the end of pre-spreading (ie, just prior to contacting the composite coating with the template) (eg, At the air-composite coating interface). In this way, the template comes into contact with the homogenous mixture, with the majority of the mixture usually coming from the imprint resist. As a result, the release properties of imprint resists generally depend on the interaction of the composite coating with the template and polymerization from the template, including the formation of defects (or lack of defects) due to the separating forces between the template and the polymerized layer. This will affect the separation of layers.

However, as shown in FIGS. 8A and 8B, the composite coating 604 includes regions 608 that are rich in pretreatment composition, respectively, such that the template 110 contacts regions of the composite coating 604 that have different physical and chemical properties. And an area 606 rich in imprint resist. For simplicity, the imprint resist in area 606 is shown replaced with a pretreatment coating, so area 606 is in direct contact with the substrate and no intermixing is shown. Therefore, the pretreatment composition in region 608 is non-uniform in thickness. In FIG. 8A, the maximum height p of the region 606 is larger than the maximum height i of the pretreatment composition so that the template 110 mainly contacts the region 606. In FIG. 8B, the maximum height i of the region 608 is larger than the maximum height p of the imprint resist so that the template 110 mainly contacts the region 608. Therefore, the separation of the template 110 from the obtained composite polymer layer and the accompanying defect density are non-uniform, which is different in the interaction between the template and the imprint resist and the interaction between the template and the pretreatment composition. Based on that. Therefore, in some pretreatment compositions (eg, pretreatment compositions that include a single monomer or a mixture of two or more monomers but no surfactant), the composite coating allows the template to be treated. It may be beneficial for a homogeneous mixture or at least a substantially homogeneous mixture to be formed at the gas-liquid interface in contact with the composite coating.

9A-9C and 10A-10C show a base layer 500 before, during and after contacting the composite coating with the template, and separating the template from the composite polymeric layer to obtain a nanoimprint lithography laminate. FIG. 6 is a cross-sectional view showing a template 110 and a composite coating on a substrate 102 that includes an adhesive layer 502 and a contact layer 502. In Figures 9A-9C, the composite coating 900 is shown as a homogeneous mixture of the pretreatment composition and the imprint resist. In FIGS. 10A-10C, composite coating 1000 is shown as a heterogeneous mixture of pretreatment composition and imprint resist.

FIG. 9A shows a cross-sectional view of initial contact between template 110 and homogeneous composite coating 900 on substrate 102. In FIG. 9B, the template 110 has been advanced toward the substrate 102 so that the composite coating 900 fills the recesses in the template 110. After the composite coating 900 is polymerized to obtain a homogeneous polymerized layer on the substrate 102, the template 110 is separated from the polymerized layer. FIG. 9C shows a cross-sectional view of a nanoimprint lithography stack 902 with a homogeneous composite polymeric layer 904.

FIG. 10A shows a cross-sectional view of initial contact between template 110 and composite coating 1000 on substrate 102. The heterogeneous composite coating 1000 comprises regions 606 and regions 608. As shown, there is little or no mixing between the imprint resist in region 606 and the pretreatment composition in region 608. In FIG. 10B, the template 110 has been advanced toward the substrate 102 so that the composite coating 1000 fills the recesses in the template 110. After the composite coating 1000 is polymerized to obtain a heterogeneous polymer layer on the substrate 102, the template 110 is separated from the polymer layer. FIG. 10C shows a cross-sectional view of a nanoimprint lithography laminate 1002 with a heterogeneous polymerized layer 1004 that includes regions 1006 and 1008 corresponding to regions 606 and 608 of the heterogeneous composite coating 1000, respectively. Therefore, the nanoimprint lithography laminate 1002 has a non-uniform or non-uniform chemical composition, a region 1006 having a composition derived from a mixture rich in imprint resist, and a region having a composition derived from a mixture rich in a pretreatment composition. And 1008. The relative size of regions 1006 and 1008 (eg, exposed surface area, covered template surface area, or volume) is at least as large as the pre-expansion prior to contact of the composite coating with the template or the extent of expansion due to contact with the template. It may vary depending in part. In some cases, region 1006 may be separated or combined with region 1008, such that the composite polymerized layer comprises a plurality of central regions separated by boundaries, and the chemistry of composite polymerized layer 1004 at the boundary. The composition differs from the chemical composition of the composite polymerized layer inside the central region.

(Use of condensable gas)
The contact between the template 110 and the composite coating described above may be performed in an atmosphere containing a condensable gas (hereinafter, referred to as “condensable gas atmosphere”). In the present specification, the condensable gas means that the recesses of the fine pattern formed on the template 110 and the gap between the mold and the substrate are filled with the gas in the atmosphere together with the pretreatment composition and the imprint resist. At this time, it refers to a gas that is condensed and liquefied by the capillary pressure generated during filling. Note that the condensable gas exists as a gas in the atmosphere before the contact between the pretreatment composition and the imprint resist and the template 110 in the contact between the composite coating and the template.

When the composite coating and the template are brought into contact with each other in a condensable gas atmosphere, the gas filled in the concave portions of the fine pattern is liquefied so that the bubbles disappear and the filling property is excellent. The condensable gas may be dissolved in the pretreatment composition and/or the imprint resist.

The boiling point of the condensable gas is not limited as long as it is equal to or lower than the ambient temperature of the mold contact step (contact between the composite coating and the template), but is preferably -10°C to 23°C, more preferably 10°C to 23°C. .. Within this range, the filling property is further excellent.

The vapor pressure of the condensable gas at the atmospheric temperature in the mold contact step is not limited as long as it is equal to or lower than the mold pressure at the time of imprinting in the mold contact step, but is preferably 0.1 to 0.4 MPa. Within this range, the filling property is further excellent. If the vapor pressure at atmospheric temperature is higher than 0.4 MPa, the effect of eliminating bubbles may not be sufficiently obtained. On the other hand, when the vapor pressure at the ambient temperature is less than 0.1 MPa, decompression is required, and the device tends to be complicated.

The atmosphere temperature in the mold contact step (contact between the composite coating and the template) is not particularly limited, but is preferably 20°C to 25°C.

As the condensable gas, specifically, chlorofluorocarbon (CFC) such as trichlorofluoromethane, fluorocarbon (FC), hydrochlorofluorocarbon (HCFC), 1,1,1,3,3-pentafluoropropane (CHF ₂ CH _{2 CF 3, HFC-245fa,} PFP) hydrofluorocarbons such as (HFC), chlorofluorocarbon hydrofluoroether (HFE) such as pentafluoroethyl methyl ether _{(CF 3 CF 2 OCH 3,} HFE-245mc) and the like .. Of these, 1,1,1,3,3-pentafluoropropane (vapor pressure at 23° C. of 0.14 MPa, from the viewpoint that the filling property is excellent when the atmosphere temperature in the mold contact step is 20° C. to 25° C. Boiling point 15° C.), trichlorofluoromethane (vapor pressure at 23° C. 0.1056 MPa, boiling point 24° C.), and pentafluoroethyl methyl ether are preferred. Further, 1,1,1,3,3-pentafluoropropane is particularly preferable from the viewpoint of excellent safety. As the condensable gas, one type may be used alone, or two or more types may be mixed and used.

Further, these condensable gases may be used as a mixture with non-condensable gases such as air, nitrogen, carbon dioxide, helium and argon. As the non-condensable gas mixed with the condensable gas, helium is preferable from the viewpoint of filling property. Helium can penetrate the mold 205. Therefore, when the recesses of the fine pattern formed on the mold 205 in the mold contact step are filled with the gas (condensable gas and helium) in the atmosphere together with the pretreatment composition and/or the imprint resist, the condensability is reduced. As the gas liquefies, the helium penetrates the mold.

(Further manufacturing process details)
<Removal of residual film>
The polymerized layer obtained by separating the template from the composite polymerized layer (mold release step) has a specific pattern shape, but in a region other than the region where the pattern shape is formed, as shown in FIG. The residual film 204 may remain. In such a case, the residual film 204 in the region to be removed of the obtained cured film (polymerized layer) 202 having the pattern shape is removed by the etching gas A or the like. Thereby, a cured film pattern having a desired uneven pattern shape (for example, a pattern shape resulting from the uneven shape of the template 110) and having no residual film (a desired portion of the surface of the substrate 102 is exposed) can be obtained.

Here, as a method of removing the residual film 204, for example, a cured film 202 having a pattern shape is formed by removing the cured film (residual film 204) which is a concave portion of the cured film 202 having a pattern shape by a method such as etching. There is a method of exposing the surface of the substrate 102 in the recesses of the pattern.

When removing the residual film 204 in the concave portion of the cured film 202 having a pattern shape by etching, the specific method is not particularly limited, and a conventionally known method, for example, an etching gas A was used. Dry etching can be used. A conventionally known dry etching apparatus can be used for the dry etching. The etching gas A is appropriately selected depending on the elemental composition of the cured film used for etching, but CF ₄ , C ₂ F ₆ , C ₃ F ₈ , CCl ₂ F ₂ , CCl ₄ , CBrF ₃ , BCl _{3 are used.} , PCl ₃ , SF ₆ , Cl _{2 and} other halogen-based gases, O ₂ , CO, CO _{2 and} other oxygen atom-containing gases, He, N ₂ , Ar and other inert gases, H ₂ and NH ₃ gases, etc. Can be used. In addition, these gases can also be mixed and used.

When the substrate 102 (substrate to be processed) used is a substrate whose adhesion to the cured film 202 is improved by surface treatment such as silane coupling treatment, silazane treatment, and organic thin film formation, Following the etching of the cured film (residual film) in the concave portion of the cured film 202 having the pattern shape, the surface treatment layer can also be removed by etching.

Through the above manufacturing process, a cured film pattern having a desired uneven pattern shape (pattern shape resulting from the uneven shape of the template 110) at a desired position and having no residual film can be obtained, and an article having a cured film pattern is obtained. be able to. Further, when the substrate 102 is processed by using the obtained cured film pattern, a substrate processing step described later is performed.

On the other hand, the obtained cured film pattern is used as an optical member (including a case where it is used as one member of an optical member) such as a diffraction grating and a polarizing plate in addition to the semiconductor processing application described later to obtain an optical component. Can also In such a case, an optical component having at least the substrate 102 and the cured film pattern arranged on the substrate 102 can be provided.

<Processing of substrate 102>
After removing the residual film, the portion of the substrate 102 whose surface is exposed is dry-etched by using the cured film pattern 202 without the residual film as a resist film. A conventionally known dry etching apparatus can be used for the dry etching. The etching gas is appropriately selected depending on the elemental composition of the cured film to be subjected to etching and the elemental composition of the substrate 102. CF ₄ , C ₂ F ₆ , C ₃ F ₈ , CCl ₂ F ₂ , CCl ₄ , _{CBrF 3, BCl 3, PCl 3} , SF 6, Cl 2 or the like halogen-containing _gas, O _{2, CO,} a gas containing oxygen atoms such as CO _2, He, an inert gas such as N _2, Ar, _H 2, NH ₃ gas or the like can be used. In addition, these gases can also be mixed and used. The etching gas A for removing the residual film and the etching gas B for processing the substrate may be the same or different.

It has already been described that the non-uniformity of the mixing of the pretreatment composition and the imprint resist may occur in the cured film 202 having the pattern shape.

The pretreatment composition preferably has a dry etching resistance equal to or higher than that of the imprint resist. Thereby, the substrate 102 can be favorably processed even in the region where the concentration of the pretreatment composition is high, and as a result, the substrate 102 can be uniformly processed.

By forming the electronic component in addition to the series of steps (manufacturing process) described above, a circuit structure based on the pattern shape caused by the uneven shape of the template 110 can be formed on the substrate 102. This makes it possible to manufacture a circuit board used in semiconductor devices and the like. Examples of the semiconductor element here include LSI, system LSI, DRAM, SDRAM, RDRAM, D-RDRAM, and NAND flash. Further, by connecting this circuit board and the circuit control mechanism of the circuit board, it is possible to form an electronic device such as a display, a camera, or a medical device.

Similarly, a cured film pattern having no residual film may be used as a resist film to process the substrate by dry etching to obtain an optical component.

Alternatively, a quartz substrate may be used as the substrate 102, and the cured film pattern 202 may be used as a resist film to process quartz by dry etching to produce a replica of the quartz imprint mold. As the material of the substrate, in addition to quartz, fused quartz, silicon, silicon nitride, organic polymer, siloxane polymer, borosilicate glass, fluorocarbon polymer, metal (for example, chromium, tantalum), hardened sapphire, or the like Combinations may be included, but are not limited to.

When the circuit board and the electronic component are manufactured, the cured film pattern 202 may be finally removed from the processed substrate, but the cured film pattern 202 may be left as a member constituting the element.

(Set of pretreatment coating material and imprint resist)
Another aspect of the present invention described above is a pre-imprint in which a liquid film to be a pretreatment coating is formed on a substrate and droplets are applied to the liquid film to promote spread of droplet components in the substrate surface direction. A treatment coating material is provided.

The pretreatment coating material has a polymerizable component and is characterized in that the interfacial energy between the applied droplets and air is less than the interfacial energy between the pretreatment coating material and air. As a result, by applying the droplet to the liquid film, the spread of the droplet component in the substrate surface direction is promoted, and a suitable imprint can be realized.

In particular, it is preferable that the imprint resist and the pretreatment coating material are provided as a set in combination. That is, the interfacial energy between the imprint resist and the air, which is the applied droplet, is smaller than the interfacial energy between the pretreatment coating material and the air. Realize a suitable imprint.

Further, as described above, the difference between the interfacial energy between the pretreatment coating material and air and the interfacial energy between the imprint resist and air is 1 mN/m to 25 mN/m, which is a set of combinations. More preferable.

Another aspect of the present invention is to provide a preferable substrate pretreatment method for imprinting by coating the substrate with a pretreatment coating material.

In addition, the present invention also includes a pattern forming method for forming a pattern on a substrate. By including the step of discontinuously dropping the resist on the substrate coated with the pretreatment coating material, the spread of the resist component in the substrate surface direction is promoted, and the time required for imprinting can be shortened.

In the following examples, the interfacial energy reported at the interface between the imprint resist and air was measured by the maximum bubble pressure method. The measurements were carried out using a BP2 bubble pressure tensiometer from Kruess GmbH in Hamburg, Germany. In the maximum bubble pressure method, the maximum internal pressure of bubbles formed in a liquid is measured using a capillary tube. The surface tension can be calculated from the Young-Laplace equation using a capillary tube of known diameter. Some of the pretreatment compositions are given values reported by the manufacturer for the interfacial energy at the pretreatment composition-air interface.

Viscosity was measured using a Brookfield DV-II+ Pro equipped with a small sample adapter with a temperature controlled bath set at 23°C. The viscosity value reported is the average of 5 measurements.

The adhesion layer cures an adhesion composition made by combining about 77 g of ISORAD 501, about 22 g of CYMEL 303ULF and about 1 g of TAG 2678 into this mixture in approximately 1900 grams of PM acetate. Then, it was formed and prepared on the substrate. The adhesion composition was spun onto a substrate (e.g., a silicon wafer) at a rotational speed of 500 to 4000 revolutions per minute so as to be substantially smooth, if not flat plate layer having a uniform thickness. The spin-on composition was exposed to actinic radiation energy at 160° C. for approximately 2 minutes. The resulting adhesion layer had a thickness of about 3 nm to about 4 nm.

In Comparative Example 1 and Examples 1 to 3, the imprint resist having a surface tension of 33 mN/m at the air/imprint resist interface was used to clarify the spread of the imprint resist on various surfaces. did. The imprint resist comprises about 45% by weight monofunctional acrylates (eg isobornyl acrylate and benzyl acrylate), about 48% by weight difunctional acrylates (eg neopentyl glycol diacrylate) and about 5% by weight. % of the photopolymerization initiator (e.g., TPO and 4265), about 3% by weight of a surfactant _{(e.g., X-R- (OCH 2 CH} 2) n OH ( wherein, R = alkyl, aryl or poly ( propylene glycol), X = H or _- (a _{OCH 2 CH 2) n OH,} n is an integer (e.g., 2～20,5～15 or 10 to 12) (e.g., X = - (OCH ₂ CH ₂ ) _n OH, R=poly(propylene glycol), and n=10 to 12)) and a fluorosurfactant (where X=perfluorinated alkyl). It was a polymerizable composition.

In Comparative Example 1, the imprint resist was directly placed on the adhesion layer of the nanoimprint lithography substrate. FIG. 11 is an image of the imprint resist droplet 1100 on the adhesion layer 1102 of the substrate after 1.7 seconds from the start of droplet ejection in the grid pattern. As can be seen in the image, the drop 1100 extends outward from the target area on the substrate. However, spreading beyond the target area was limited, and the area of the exposed adhesion layer 1102 exceeded that of the drop 1100. The rings visible in this and other images, such as ring 1104, are Newton interference rings, and the Newton interference rings are those that exhibit a difference in thickness in various regions of the drop. The resist drop size was approximately 2.5 pL. In FIG. 11, a 2×7 (pitch) ² interleaved grid of drops (eg, 2 units horizontally, 3.5 units between lines). Each of the following lines was moved horizontally by one unit.

In Examples 1 to 3, Pretreatment Composition A to Pretreatment Composition C were each placed on a nanoimprint lithography substrate to form a pretreatment coating. An imprint resist drop was placed on the pretreatment coating. 12 to 14 show images of the composite coating after the ejection of the imprint resist droplets is started. Mixing occurs between the pretreatment composition and the imprint resist in these examples, but for simplicity the imprint resist drops and pretreatment coating are described below without any consideration of the mix. .. The pretreatment composition was placed on the wafer substrate via spin-on coating. More specifically, the pretreatment composition was dissolved in PGMEA (0.3 wt% pretreatment composition/99.7 wt% PGMEA) and spun on onto the wafer substrate. Upon evaporation of the solvent, the typical thickness of the pretreatment coating obtained on the substrate was in the range of 5 nm to 10 nm (eg 8 nm). The size of the resist droplet was about 2.5 pL in FIGS. 12 and 14 are 2×7 (pitch) ² interleaved grids of drops (eg, 2 units horizontally, 3.5 units between lines). Each of the following lines was moved horizontally by one unit. FIG. 13 shows a 2×6 (pitch) ² interleaved grating. The pitch value was 84.5 μm. The ratio of the resist volume to the pretreatment layer was in the range of 1 to 15 (for example, 6 to 7).

Table 1 lists the surface tensions (gas-liquid interface) of the pretreatment compositions A to C used in Examples 1 to 3 and the imprint resist.

In Example 1, an imprint resist drop was placed on a substrate with a coating of Pretreatment Composition A (Sartomer 492 or "SR492"). SR492 from Sartomer, Inc. (Pennsylvania, USA) is a propoxylated (3) trimethylolpropane triacrylate (a polyfunctional acrylate). FIG. 12 shows an image of the imprint resist drop 1200 on the pretreatment coating 1202 and the resulting composite coating 1204 1.7 seconds after starting the discharge of the discontinuities in the interleaved grid pattern. In this embodiment, the droplet retains the shape of a spherical crown and the spread of the imprint resist is limited. As seen in FIG. 12, the drop 1200 spreads beyond the imprint resist on the adhesion layer in Comparative Example 1, but the drop remains separated by the pretreatment coating 1202, forming a border 1206 around the drop. To do. Some components of the imprint resist extend beyond the center of the drop, forming a region 1208 around the drop 1200. Regions 1208 are separated by a pretreatment coating 1202. The spread limitation is due at least in part to the small difference in surface tension between the pretreatment composition A and the imprint resist (1 mN/m), which is a significant energy advantage for droplet spread. There is no. It is understood that other factors such as friction also affect the extent of spread.

In Example 2, an imprint resist drop was placed on a substrate with a coating of Pretreatment Composition B (Sartomer 351HP or "SR351HP"). SR351HP from Sartomer, Inc. (Pennsylvania, USA) is trimethylolpropane triacrylate (a polyfunctional acrylate). FIG. 13 shows an image of imprint resist drops 1300 on pretreatment coating 1302 and resulting composite coating 1304 1.7 seconds after initiating drops ejection in a square grid pattern. After 1.7 seconds, the drop 1300 covers most of the surface area of the substrate and is separated by the pretreatment coating 1302, forming a boundary 1306 around the drop. Since the drop 1300 is more uniform than the drop 1200 of Example 1, a significant improvement over the spread of Example 1 is observed. The greater extent of spreading is that the difference in surface tension between the pretreatment composition B and the imprint resist is larger than the difference in surface tension between the pretreatment composition A and the imprint resist of Example 1 ( 3.4 mN/m), at least in part.

In Example 3, an imprint resist drop was placed on a substrate with a coating of Pretreatment Composition C (Sartomer 399LV or "SR399LV"). SR399LV from Sartomer, Inc. (Pennsylvania, USA) is dipentaerythritol pentaacrylate (a polyfunctional acrylate). FIG. 14 shows an image of the imprint resist drop 1400 on the pretreatment coating 1402 and the resulting composite coating 1404 1.7 seconds after initiating the drop ejection in the triangular grid pattern. As seen in FIG. 14, the drops 1400 are separated by a pretreatment coating 1402 at boundaries 1406. However, most of the imprint resist collects at the drop boundaries, so most of the polymerizable material is at the drop boundaries and the drop centers are substantially empty. The degree of spread contributes at least in part to the large difference in surface tension between the pretreatment composition C and the imprint resist (6.9 mN/m).

The defect density was measured according to the pre-spreading time for the imprint resists of Examples 1 to 3 and the pretreatment composition B of Example 2. FIG. 15 shows the defect density (void) due to the non-filling of the template. A plot 1500 shows the defect density (the number of defects per 1 cm ² ) according to the spreading time (seconds) with respect to a line/space pattern regions of 28 nm. The defect density becomes close to 0.1/cm ^{2 in} 0.9 seconds. Plot 1502 shows the defect density (number of defects per cm ² ) as a function of spreading time (seconds) over the field where the feature size is in a range. The defect density becomes close to 0.1/cm ^{2 in} 1 second. By way of comparison, without pretreatment, defect densities approaching 0.1/cm ² are typically achieved over the entire field with a spreading time of 2.5 seconds to 3.0 seconds.

Table 2 shows the characteristics of the pretreatment compositions PC1 to PC9. The important characteristics of PC1 to PC9 are shown below. Viscosity was measured as described herein at a temperature of 23°C. In order to calculate the diameter ratio (Diam.Ratio) at 500 ms as shown in Table 2, an imprint resist drop (drop size about 25 pL) was added to the pretreatment composition (about 8 nm to 10 nm) on top of the adhesion layer. Thickness) was spread on the coated substrate, and the droplet diameter was recorded at an elapsed time of 500 ms. At 500 ms, the imprint resist drop size with each pretreatment composition was divided by the imprint resist drop size on the adhesion layer without the pretreatment composition. As shown in Table 2, the imprint resist drop size on PC1 at 500 ms was 60% larger than the imprint resist drop size on the adhesion layer without the pretreatment coating. FIG. 16 shows the droplet diameter (μm) according to the time (ms) for the pretreatment compositions PC1 to PC9. The relative etch resistance is the Onishi parameter of each pretreatment composition divided by the Onishi parameter of the imprint resist. Table 2 shows the relative etching resistance of PC1 to PC9 (ratio between the etching resistance of the pretreatment composition and the etching resistance of the imprint resist).
PC1: Trimethylolpropane triacrylate (Sartomer)
PC2: trimethylolpropane ethoxylate triacrylate, n about 1.3 (Osaka Organic Chemical Industry Co., Ltd.)
PC3: 1,12-dodecanediol diacrylate PC4: Poly(ethylene glycol) diacrylate, average Mn=575 (Sigma-Aldrich)
PC5: Tetraethylene glycol diacrylate (Sartomer)
PC6: 1,3-adamantane diol diacrylate PC7: nonanediol diacrylate PC8: m-xylylene diacrylate PC9: tricyclodecane dimethanol diacrylate (Sartomer)

Pretreatment composition PC3 and pretreatment composition PC9 were combined at various weight ratios to obtain pretreatment composition PC10 to pretreatment composition PC13 having the weight ratios shown in Table 3. A synergistic effect was revealed by a comparison of the properties of PC3 and PC9 and the mixtures formed from them. For example, PC3 has a relatively low viscosity and allows for relatively fast template filling, but relatively low etch resistance. In contrast, PC9 has relatively good etching resistance and film stability (low evaporation loss), but is relatively viscous and exhibits relatively slow template loading. However, the combination of PC3 and PC9 resulted in a pretreatment composition with beneficial properties including relatively low viscosity, relatively fast template loading and relatively good etch resistance. For example, the pretreatment composition containing 30 wt% PC3 and 70 wt% PC9 has a surface tension of 37.2 mN/m, a diameter ratio of 1.61, and an Onishi parameter of 3.5. Was found.

FIG. 17A shows viscosity plots for pretreatment compositions containing various ratios of PC3 and PC9 (ie, 100 wt% PC3 to 100 wt% PC9). FIG. 17B shows drop sizes (measured as described with respect to Table 2) for PC3, PC13, PC12, PC11, PC10 and PC9. FIG. 17C shows the surface tension (mN/m) for the PC3 and PC9 fractions.

Many embodiments have been described. Nevertheless, it is understood that various changes can be made without departing from the spirit and scope of the disclosure. Accordingly, other embodiments are also within the scope of the appended claims.

Claims (8)

Imprint method,
Discontinuities of the imprint resist are disposed on the liquid pretreatment coating on the substrate such that the discontinuities of the imprint resist spread over the liquid pretreatment coating, resulting in a spread imprint resist.
Here, the liquid pretreatment coating is composed of a polymerizable component, the imprint resist is a polymerizable composition,
Contacting the spread imprint resist with a template,
Polymerizing the spread imprint resist and the pretreatment coating to obtain a polymerized layer on the substrate,
Have
The imprint method, wherein the surface tension of the liquid pretreatment coating is higher than the surface tension of the imprint resist. The imprint method according to claim 1, wherein the pretreatment coating does not include a polymerization initiator. The imprint method of claim 1, wherein the spread imprint resist and the liquid pretreatment coating form a composite polymerizable coating before the spread imprint resist contacts the template. The imprint method of claim 1, further comprising separating the template from the polymerized layer. The imprint method according to claim 1, wherein the thickness of the liquid pretreatment coating on the substrate is 1 nm to 15 nm. The imprint method according to claim 1, wherein the surface tension of the liquid pretreatment coating is 0.5 mN/m to 25 mN/m higher than the surface tension of the imprint resist. A method of manufacturing a semiconductor device, the manufacturing method comprising:
Placing a liquid pretreatment coating on the substrate,
Wherein the liquid pretreatment coating comprises a polymerizable component,
Discontinuities of the imprint resist are disposed on the liquid pretreatment coating on the substrate such that the discontinuities of the imprint resist spread over the liquid pretreatment coating, resulting in a spread imprint resist.
Here, the imprint resist is a polymerizable composition, the surface tension of the liquid pretreatment coating is higher than the surface tension of the imprint resist,
Contacting the spread imprint resist with a template,
Polymerizing the spread imprint resist and the pretreatment coating to obtain a polymerized layer on the substrate,
Separating the template from the polymeric layer, and etching the substrate through the polymeric layer,
A method of manufacturing a semiconductor device, comprising: Installation of the liquid pretreatment coating comprises coating the substrate using spin coating, dip coating, chemical vapor deposition (CVD), or physical vapor deposition (PVD),
The method further comprises processing the substrate using an imprint lithography system to produce a polymerized layer on the substrate, and etching the substrate using reactive ion etching or high density etching. And
The manufacturing method according to claim 7.