JP7446799B2 - Imprint method - Google Patents

Description

The present invention relates to an imprint method.

As the demand for miniaturization of semiconductor devices and MEMS advances, development of imprint technology is progressing, in which uncured resin on a substrate is molded to form a resin pattern on the substrate. By using imprint technology, fine structures on the order of nanometers can be formed on a substrate.

One of the imprint technologies is the photocuring method. In this imprint method using a photocuring method, first, an uncured photocurable composition (also called a photocurable resin or imprint material) is supplied onto a substrate (wafer). Next, the resin on the substrate is brought into contact with the mold (mold contact step). Then, the resin is cured by irradiating it with light (ultraviolet rays) (curing step) while the resin and mold are in contact with each other. After the resin is cured, the distance between the substrate and the mold is widened (mold release step), whereby the mold is separated from the cured resin and a resin pattern is formed on the substrate.

Furthermore, techniques have been disclosed in which an imprint material is applied to the entire surface of a substrate in advance for the purpose of improving throughput, and a technique is applied in which an imprint material is applied to multiple shots at once. At this time, if the unmolded contact area that is scheduled to come into contact with the mold is irradiated with light, the imprint material will harden before contact with the mold, so pattern formation must be performed correctly for the relevant shot. I can't.

Patent Document 1 describes an advantageous technique for defining, with high precision, an irradiation area that is irradiated with light from a light source.

Japanese Patent Application Publication No. 2018-41774

When carrying out the substrate from the apparatus, it is necessary to completely cure the photocurable composition applied to the substrate before carrying it out. This is because chemicals generally cause chemical contamination when the photocurable composition on the substrate is in an uncured state.

In particular, when performing imprint processing on a substrate that has been coated with a photocurable composition on the entire surface in advance, the uncured photocurable composition remaining in the untreated area after all imprint processing is performed. On the other hand, it is necessary to perform a curing process within the imprint apparatus before carrying out the substrate.

In a semiconductor light irradiation apparatus in which the number of substrates processed per unit time is one of the performance indicators, the above-mentioned curing process is required to be performed as quickly as possible.

Therefore, an object of the present invention is to provide an imprint method that reduces equipment contamination during transportation and realizes efficient photocuring by light irradiation.

In view of the above problems, the imprint method according to the present invention includes:
An imprint method comprising a mold contacting step of bringing a photocurable composition placed on a substrate into contact with a mold, and a light irradiation step of irradiating the photocurable composition with light to form a cured product. hand,
In the light irradiation step, information on the placement area of the uncured photocurable composition on the substrate, information on the contact area between the mold and the substrate, and information on the area of the mold to be contacted after light irradiation. An imprinting method characterized in that the position of a light irradiation area including a mold contact area and a peripheral area of the mold contact area is determined based on information.

According to the present invention, it is possible to provide an imprint method that reduces equipment contamination during transportation and realizes efficient photocuring by light irradiation.

Imprint device of first embodiment Substrate light irradiation treatment using conventional technology Substrate light irradiation treatment using this technology General molds and molds with a light shielding area around the pattern Substrate light irradiation treatment in a mold with a light shielding part Substrate light irradiation processing using a light irradiation mechanism with limited irradiation area

Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a schematic configuration diagram of an imprint apparatus according to an embodiment of the present invention. The imprint device will be explained.

In FIG. 1, a substrate stage 5 is provided on a surface plate 1 via a stage driving means 4 consisting of a linear motor or the like. The substrate stage 5 holds a semiconductor wafer 6, which is a substrate, and is configured to be movable.

The stage driving means 4 moves the substrate stage 5 in the illustrated XY directions parallel to the upper surface of the surface plate 1. The substrate stage 5 feeds back position information detected by means (not shown), such as an interferometer or an encoder, to the stage driving means 4.

A frame 2 is provided on the surface plate 1 via a damper 3 that cancels vibrations from the floor, and an imprint module 7 having a Z drive mechanism is attached to the frame 2.

The imprint module 7 holds a mold 8 at a position facing the semiconductor wafer 6 . The light emitted from the light irradiation source 12 passes through the shutter 14, passes through the reflection unit 13, the irradiation area control mechanism 16, and the imprint module 7, and is irradiated onto the semiconductor wafer 6.

The irradiation area control mechanism 16 only needs to be able to control the irradiation area onto the semiconductor wafer 6. For example, the position and area of light irradiation from the light source may be controlled by configuring a movable blade that physically blocks light, or a mirror device such as a digital mirror device may be used in the optical path to the substrate. By arranging the light irradiation light, an arbitrary area may be irradiated with light.

In the present invention, it is sufficient that the apparatus is provided with a mechanism capable of controlling the irradiation area of the irradiation light on the semiconductor wafer 6, and there is no need to limit the unit configuration of the irradiation area control mechanism.

The mold 8 has an uneven pattern formed on its surface facing the semiconductor wafer 6. The imprint module 7 can be driven up and down in a direction perpendicular to the surface of the semiconductor wafer 6 (Z direction in the figure), and can press the mold 8 onto the photocurable composition applied onto the semiconductor wafer 6 or An operation of separating it from the semiconductor wafer 6 is performed.

A scope 15 is mounted within the imprint module 7 for the purpose of measuring the relative position of the semiconductor wafer 6 and the mold 8 when pressing the mold against the photocurable composition. In such an imprint apparatus, a die-by-die alignment method is generally used as a method for aligning the semiconductor wafer type 6 and the type 8.

The die-by-die alignment method is a method in which alignment is performed by detecting a plurality of alignment marks formed in each of a plurality of shot areas formed on a semiconductor wafer 6 and a plurality of alignment marks formed on a mold 8. . The scope 15 for detecting alignment marks is configured to include a sensor for detecting an image of the mark and an optical system for forming an image of the mark on the sensor.

Each of the units described above is controlled by a central processing unit (hereinafter abbreviated as CPU) 11 and performs a series of imprint operations.

<First embodiment>
Using the first embodiment, by controlling the irradiation area of light irradiation (light irradiation) on a semiconductor wafer on which a photocurable composition is disposed over the entire semiconductor wafer, semiconductor wafers can be efficiently applied while performing mold contact treatment. An example in which all the photocurable compositions on a wafer are cured will be described.

First, a light irradiation process performed by a conventional technique without applying the present technique will be described using FIG. 2.

FIG. 2(a) shows a substrate (2-1) and an area (anticipated contact area) (2-2) where a mold on the substrate is expected to come into contact.

FIG. 2(b) shows the light irradiated area (2-3) and the area under light irradiation treatment (2-4) when contact with the substrate (2-1) starts from the upper left. . The white area (2-5) is an area that is not yet irradiated with light (unirradiated area), which is scheduled to be irradiated after the area (2-4) that is currently being irradiated with light.

FIG. 2(c) is a diagram of the substrate showing light irradiated areas when processing of all planned contact areas is completed. In the case of a substrate that has already been coated with a photocurable composition, all the white areas (2-5) other than the irradiated area (2-3) must be irradiated with light before the substrate is taken out. There is.

FIG. 2(d) shows an example of the drive locus (2-7) of the irradiation area when the irradiation area (2-6) of the light irradiation light is irradiated with light by scanning drive to the unirradiated area on the substrate. It shows. If it is possible to further widen the irradiation area, it is also possible to reduce the driving locus.

FIG. 2E is a diagram showing a state (2-3) in which there is no unirradiated area and the entire surface of the substrate has been irradiated with light. In this way, when the entire surface of the substrate is irradiated with light, the substrate can be transported out of the apparatus. The above is the flow of processing a substrate coated with a photocurable composition using the conventional technique.

Next, a method for efficiently photocuring a substrate using the present invention will be described.

FIG. 3(a) shows a substrate (3-1) and a planned contact area (3-2) on the substrate. The numbers written inside the expected contact area (3-2) indicate the processing order, and the contact processing is executed in order from the smallest number. A method for determining a light irradiation area when this technology is applied will be explained.

The light irradiation area (3-3) includes the positions of all planned contact areas on the substrate and the size of the mold used for contact (in FIG. 3, the contact area (3-3) is determined by the device user before the start of product processing). 2) is determined using the information expressed in the size of 2). In this embodiment, since the semiconductor wafer is a semiconductor wafer on which a photocurable composition is disposed throughout, all areas on the substrate are arranged with an uncured photocurable composition disposed before the start of light irradiation. Obtained as area information. Furthermore, information on the area to be touched after light irradiation in each process is obtained according to the order of the processes.

In the present embodiment, a state in which there is another planned contact area in the vertical direction of one side of the target contact area is defined as a state in which adjacent contact areas exist.

In the case of a side where adjacent contact areas exist, the edge of the light irradiation area is set at a position from the midpoint between the contact areas to the adjacent contact area. In the case of a side where there is no adjacent contact area, a light irradiation area is set up to the edge of the substrate in a direction perpendicular to that side.

Furthermore, if there are two sides on which no adjacent contact area exists, and those sides are two adjacent sides in the contact area, the area from the orthogonal point to the diagonal direction of the substrate edge is also set as the light irradiation area.

A method of determining the light irradiation area (3-3) when irradiating the contact area 1 (3-4) with light based on the above information will be explained using FIG. 3.

Contact area 1 (3-4) has adjacent contact area 2 (3-6) and contact area 5 (3-5) on the right side and bottom side, and there are no adjacent contact areas on the left side and top side. Further, since the left side and the top side, where there is no adjacent contact area, are adjacent sides, the upper left direction is also set as a light irradiation area.

As described above, the lower side of the light irradiation area of contact area 1 (3-4) is moved from the intermediate position of the distance between the lower side of contact area 1 (3-4) and the upper side of contact area 5 (3-5). 5) is set up to the top side.

The right side of the light irradiation area of contact area 1 (3-4) is set between the intermediate position between the right side of contact area 1 and the left side of contact area 2 (3-6) to the left side of contact area 2 (3-6). Ru.

The left side and the upper side of the light irradiation area of the contact area 1 (3-4) are set at positions that can cover up to the edge of the substrate.

Next, a method for determining the irradiation area in the light irradiation process for the contact area 2 (3-6) will be explained using FIG. 3(b). In the contact area 2 (3-6), there are adjacent contact areas on the left side, right side, and bottom side, and there is no adjacent contact area on the top side.

As described above, as shown in FIG. 3(b), the left side, right side, and bottom side of the light irradiation area of contact area 2 (3-6) are set from the midpoint of the adjacent contact area to the front of the contact area, and the light irradiation area The upper side of the irradiation area is set at a position that can cover up to the edge of the substrate.

Next, a method for determining the light irradiation area of the contact area 3 (3-8) will be explained using FIG. 3(c). In the contact area 3, there are adjacent contact areas on the left side and the bottom side, and there are no adjacent contact areas on the top and right sides.

In this case, the left side and bottom side of the light irradiation area are set between the midpoint of the adjacent contact area and the front of the adjacent contact area, and the right side and top side of the light irradiation area are set at a position that can cover the edge of the board. Set.

In this way, by determining the light irradiation area in the light irradiation process for each contact area using the position of the contact area on the substrate and the size information of the mold, the substrate other than the contact area can be efficiently removed while performing contact processing. The above photocurable composition can also be cured.

<Second embodiment>
Among the molds used in imprint apparatuses, there are molds that are treated with a Cr layer that partially blocks irradiated light.

The purpose of partially blocking the irradiated light is to prevent the irradiated light from irradiating the photocurable composition in another area to be contacted.

In the light irradiation step of a specific partial area, if the photocurable composition in the area to be contacted later is cured, a process of pressing a mold onto the position where the cured photocurable composition is present will occur. Since the cured product obtained by curing the photocurable composition has very high hardness, if the mold comes into contact with the cured product, there is a risk that the pattern of the mold will be destroyed by the cured product.

It is possible to narrow down the range of light irradiation by equipping the light irradiation mechanism of the device with a mechanism that narrows down the light irradiation area, but by placing a light shielding film around the pattern of the mold, light can be blocked closer to the substrate. This makes it possible to irradiate only a desired area with light.

However, since this method requires a process to form a Cr layer, it is up to the user to decide whether to use a device that actually has a squeezing mechanism or to apply the process to the mold, taking into account cost-effectiveness.

The mold used in the imprint apparatus will be explained using FIG. 4. FIG. 4(a) is a view of a mold used in an imprint apparatus viewed from two directions: right above and sideways. Generally, the mold is made of quartz glass or the like that allows light to pass through the entire surface.

Next, FIG. 4(b) shows an example of a mold in which a Cr layer is formed around the pattern part for the purpose of partially blocking the irradiation light. The irradiation light is shielded from the periphery of the pattern portion by the light-shielding region (4-2) formed around the pattern portion (4-1).

An example of performing pattern contact processing on a substrate using the mask shown in FIG. 4(b) will be described with reference to FIG.

FIG. 5(a) shows an example in which light irradiation was performed using a light irradiation area determined under the same conditions as in Example 1, but using a mold in which the periphery of the pattern part was shielded from light by a Cr layer. Therefore, an unirradiated area (5-1) that is not irradiated remains within the irradiated area.

Therefore, when performing contact treatment using a mold with a light-shielding film as shown in this example, in addition to the method of determining the light irradiation area used in Example 1, Set to irradiation area.

A method for determining the light irradiation area of the contact area 2 (5-2) will be explained using FIG. 5(b). By setting the light irradiation area of contact area 2 (5-2) to cover the unirradiated area (5-1) of contact area 1, the light irradiation process of contact area 2 (5-2) is completed. At this point, the unirradiated area (5-1) of the contact area 1 has also been irradiated with light.

An example in which the light irradiation area of contact area 3 (5-3) is similarly determined is shown in FIG. 5(c). At the same time that the contact area 3 (5-3) is subjected to the light irradiation process, the area from the contact area 2 (5-2) and the contact area 3 (5-3) to the right end of the substrate is irradiated with light.

The processing order of the contact areas used in this embodiment has been explained using the case where the processing is performed from left to right. However, when the light irradiation area is determined by this method, if the rows of contact areas are different, for example, the light irradiation process for the pattern periphery of contact area 3 (5-3) is different from the light irradiation process for contact area 4 (5-4). cannot be carried out at times.

In this case, the light irradiation process may be performed on the remaining unirradiated area by performing the light irradiation process on the contact area at the right end in each column before carrying out the substrate. As another method, as shown in FIG. 5(d), when contact area 7 (5-5) is exposed to light, contact area 6 (5-6) and contact area 3 (5-3) are exposed to light. May be implemented.

The light irradiation area may be limited depending on the light irradiation area control mechanism installed in the device. For example, if the size of the light irradiation area (6-1) shown in FIG. 6(a) is the largest of the light irradiation areas, contact area 2 (6-2) is 6-3), the substrate portion on the right side of the contact area 3 cannot be irradiated with light simultaneously with the light irradiation process of the contact area 3.

When the present technology is applied to the device having the light irradiation area limitation described above, the light irradiation area (6-4) will be in a state as shown in FIG. 6(b) after the processing of all contact areas is completed.

In order to inform the user of the state (cured/uncured) of the photocurable composition on the substrate, an image diagram such as that shown in FIG. It may be possible for the user to confirm.

As shown in FIG. 6(c), as a method of irradiating the unirradiated area in FIG. By performing the light irradiation treatment along the substrate, the light irradiation treatment can be performed on all the photocurable compositions on the substrate. In this case as well, it is advantageous in terms of processing time compared to the substrate pretreatment (FIG. 2(d)) in which the pretreatment is limited to only the contact area.

By applying the present technology in this way, it is possible to provide an imprint method that can efficiently cure a photocurable composition on a substrate.

In particular, when performing imprint processing on a substrate whose entire surface has been previously coated with a photocurable composition, it is possible to provide a method for efficiently curing the substrate.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

6 semiconductor wafer 7 imprint module 8 type 11 control unit 12 light source 16 irradiation area control mechanism

Claims (6)

a mold contacting step of bringing the photocurable composition placed on the substrate into contact with the mold;
a light irradiation step of irradiating the photocurable composition with light to form a cured product;
An imprint method comprising:
In the light irradiation step, information on the placement area of the uncured photocurable composition on the substrate, information on the contact area between the mold and the substrate, and information on the area of the mold to be contacted after light irradiation. An imprinting method characterized in that the position of a light irradiation area including a mold contact area and a peripheral area of the mold contact area is determined based on information. a mold contacting step of bringing the photocurable composition placed on the substrate into contact with the mold;
a light irradiation step of irradiating the photocurable composition with light to form a cured product;
An imprint method comprising:
In the light irradiation step, information on the placement area of the uncured photocurable composition on the substrate, information on the contact area between the mold and the substrate, and information on the area of the mold to be contacted after light irradiation. An imprint method characterized in that a light irradiation area is determined based on information,
The light irradiation step includes a step of irradiating the area including the mold contact area up to the edge of the substrate when there is no other area to be contacted in the vertical direction of one side of the area of the mold to be contacted up to the edge of the substrate. An imprint method. In the light irradiation step, if there is another area to be contacted in the vertical direction of one side of the area to be contacted of the mold up to the edge of the substrate, the irradiation area is adjusted so as not to irradiate the other area to be contacted with light. The imprint method according to claim 1 or 2, wherein an edge of is set. a mold contacting step of bringing the photocurable composition placed on the substrate into contact with the mold;
a light irradiation step of irradiating the photocurable composition with light to form a cured product;
An imprint method comprising:
In the light irradiation step, information on the placement area of the uncured photocurable composition on the substrate, information on the contact area between the mold and the substrate, and information on the area of the mold to be contacted after light irradiation. An imprint method characterized in that a light irradiation area is determined based on information,
The light irradiation step is an imprint method in which, if there is a light irradiated area in the vertical direction of one side of the area to be contacted, the irradiation area is set to include the light irradiated area. 5. The imprint method according to claim 1, wherein in the light irradiation step, the irradiation area is changed by operating a movable blade. 5. The imprint method according to claim 1, wherein in the light irradiation step, the irradiation area is changed by arranging a mirror device on the optical path up to the substrate.

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