JP4734360B2 - Nanoparticle thin film, method for producing nanoparticle thin film, nanoparticle thin film pattern forming method, and circuit pattern forming method - Google Patents

Description

  The present invention relates to a nanoparticle thin film formed of core-shell structured nanoparticles having a metal core and an organic material shell, a method for producing the nanoparticle thin film, and a circuit forming method using this production method.

  In recent years, research has been conducted on a technique for patterning by forming a nanoparticle film on a substrate. By patterning the nanoparticle film on the substrate, for example, application to a near-field optical device is expected. Further, when the nanoparticles in the film are formed of a metal, by heating it, a metal wiring pattern can be formed, and a circuit composed of the metal wiring can be manufactured. Since the melting point of the nanoparticles is low, a circuit is formed using nanoparticles dispersed in a polymer binder, and then heated to obtain a metal wiring circuit.

  As a technique for patterning nanoparticles, for example, there is a method of depositing nanoparticles and then processing a nanoparticle film deposited by dry etching. There is also a method of applying a nanoparticle film to a patterned photoresist. Patent Document 1 discloses a method for forming a circuit using a paste containing metal nanoparticles. Furthermore, a method of forming a circuit by directly applying nanoparticles to a substrate without using a polymer binder has been developed.

  Among the methods for patterning a nanoparticle film, in the case of a method of patterning a film in which metal nanoparticles are present in an organic material by dry etching, the object to be processed is a metal-organic composite. For this reason, there exists a problem that control of an etching rate and suppression of a residue are difficult.

  In the case of a method of applying a nanoparticle film to a patterned photoresist, it is necessary to employ water-dispersed nanoparticles that do not require the use of an organic solvent so that the photoresist does not dissolve. Water-dispersed nanoparticles are nanoparticles with exposed metal on the surface, or core-shell structured nanoparticles with a metal core and an organic material shell, and the organic material contains a very small amount of water such as citric acid. It is limited to organic substances with good affinity. When other organic substances are used for the shell, the particles are aggregated in water, and there is a problem that a good pattern cannot be obtained.

  And, in order to manufacture miniaturized near-field optical devices and metal wiring circuits using patterned nanoparticles, a technology for forming nanoparticles having a diameter of about several nanometers on the substrate with a good adhesion and thickness Improvement is demanded.

When a nanoparticle film is formed on a substrate, there is a method in which a silane coupling agent is applied in advance to the substrate surface in order to improve adhesion. In this case, electrostatic attraction between the particles and between the particle and the substrate must be created. In this method, in order to increase the amount of particles adhering to the substrate and increase the thickness of the nanoparticle film, the particles need to have a size of about several tens of nanometers with high interaction between the particles, and it is difficult to refine the pattern. There is a problem that.
JP 2007-73856 A

  The present invention has been made in consideration of the above circumstances, and the object of the present invention is to provide a nanoparticle thin film pattern forming method, a circuit pattern forming method and a nanoparticle thin film suitable for the same that enable fine patterning. And providing a manufacturing method thereof.

  The nanoparticle thin film of one embodiment of the present invention is formed by chemically bonding a core-shell nanoparticle formed of a shell of an organic substance having a double bond and a metal core to a monomer having a double bond. The nanoparticle thin film is characterized in that the nanoparticle-derived particles are bonded via the monomer-derived structural portion to form a three-dimensional network structure.

  Here, it is preferable that the organic substance is undecene thiol or a derivative thereof, and the monomer is a methacrylate or a derivative thereof.

  Here, it is desirable to contain α, α′-azobisisobutyronitrile, bis (cyclohexylsulfonyl) diazomethane, or a derivative of an azo compound, which is a radical polymerization initiator.

  Here, the film thickness is desirably 50 nm or more.

  A method of manufacturing a nanoparticle thin film of one embodiment of the present invention includes a core-shell type nanoparticle formed of a shell of an organic substance having a double bond and a metal core, a monomer having a double bond, and initiation of radical polymerization. Dissolving the agent in a solvent to prepare a dip solution, immersing the substrate in the dip solution, heating the dip solution in which the substrate is immersed, and reacting the organic substance with the monomer, The method includes a step of cooling the dip solution, and a step of removing the substrate from the dip solution and cleaning it.

  Here, the organic substance is undecene thiol or a derivative thereof, the monomer is methacrylate or a derivative thereof, and the radical polymerization initiator is α, α′-azobisisobutyronitrile, Desirably, it is a derivative of bis (cyclohexylsulfonyl) diazomethane or an azo compound.

The method for forming a nanoparticle thin film pattern of one embodiment of the present invention includes a step of forming a metal layer on a substrate, a step of forming a resist pattern on the metal layer, and etching the metal layer using the resist pattern as a mask. a step, a step of removing the resist pattern, forming a nanoparticle thin film on the substrate, by ultrasound, have a step of selectively removing the nanoparticle thin film of the metal layer surface, wherein The step of forming a nanoparticle thin film on a substrate includes a core-shell type nanoparticle formed of a shell of an organic substance having a double bond and a metal core, a monomer having a double bond, and a radical polymerization initiator. Dissolving in a solvent to prepare a dip solution, immersing the substrate in the dip solution, heating the dip solution in which the substrate is immersed, and the organic substance and the monomer A step of reacting, and a step of cooling the dip solution, characterized by chromatic and washing was taken out the substrate from the dipping solution.

  Here, after the step of selectively removing the nanoparticle thin film on the surface of the metal layer by ultrasonic waves, the step of etching the metal layer, the step of forming an oxide on the nanoparticle thin film, It is desirable to have a step of forming a resist pattern on the oxide and a step of selectively exposing a part of the nanoparticle thin film by etching the oxide using the resist pattern as a mask.

  Here, the step of forming the nanoparticle thin film on the substrate includes a core-shell type nanoparticle formed of a shell of an organic substance having a double bond and a metal core, a monomer having a double bond, and a radical. Dissolving a polymerization initiator in a solvent to prepare a dip solution, immersing the substrate in the dip solution, heating the dip solution in which the substrate is immersed, and reacting the organic substance with the monomer Preferably, the method includes a step of cooling the dip solution and a step of removing the substrate from the dip solution and cleaning it.

The circuit pattern forming method of one embodiment of the present invention includes a step of forming a metal layer on a substrate, a step of forming a resist pattern on the metal layer, and a step of etching the metal layer using the resist pattern as a mask. Removing the resist pattern; forming a nanoparticle thin film on the substrate; selectively removing the nanoparticle thin film on the surface of the metal layer by ultrasonic; and after the step of selectively removing the nanoparticle thin film, possess etching the metal layer, the step of metallizing the nanoparticle thin film by heating the substrate above 130 ° C., the substrate The step of forming a nanoparticle thin film on the core comprises a core-shell type nanoparticle formed of a shell of an organic substance having a double bond and a metal core, a monomer having a double bond, a A step of dissolving a cal polymerization initiator in a solvent to prepare a dip solution, a step of immersing the substrate in the dip solution, a step of heating the dip solution in which the substrate is immersed and reacting the organic substance with the monomer When, characterized by chromatic cooling the said dipping solution, and a step of washing takes out the substrate from the dipping solution.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the nanoparticle thin film pattern formation method and circuit pattern formation method which enable fine patterning, the nanoparticle thin film suitable for this, and its manufacturing method.

  Hereinafter, a nanoparticle thin film, a method for producing a nanoparticle thin film, a method for forming a nanoparticle thin film pattern, and a method for forming a circuit pattern will be described with reference to the drawings.

(First embodiment)
In the nanoparticle thin film according to the first embodiment of the present invention, a core-shell type nanoparticle formed of a shell of an organic substance having a double bond and a metal core is chemically bonded to a monomer having a double bond. It is a nanoparticle thin film formed. And the particle | grains derived from the said nanoparticle couple | bond together through the structure part derived from the said monomer, and form the three-dimensional network structure.

  The following is an example of a structure in which the metal is gold (Au), the organic substance is undecene thiol, the monomer is methacrylate, and the undecene thiol and methacrylate are polymerized using a derivative of an azo compound as a radical polymerization initiator. Explained.

  FIG. 1 is a conceptual diagram of a cross-sectional structure of the nanoparticle thin film of the present embodiment. For example, a nanoparticle thin film having a thickness of about 1 μm is formed on a substrate 10 made of glass. And this nanoparticle thin film has Au as the core and undecenethiol having a double bond as a shell. 3D network structure formed by doing so. In other words, the metal nanoparticle-derived particles 12 are chemically bonded via the monomer-derived structural portion 14 to form a three-dimensional network structure. More specifically, a core of Au forms a three-dimensional network structure in which the cores are connected via an undecene thiol-methacrylate copolymer.

  Next, the manufacturing method of the nanoparticle thin film of this Embodiment is demonstrated. In this production method, a core-shell type nanoparticle formed of an organic substance shell having a double bond and a metal core, a monomer having a double bond, and a radical polymerization initiator are dissolved in a solvent to prepare a dip solution. A step of immersing the substrate in the dip solution, a step of heating the dip solution immersed in the substrate to react the organic substance with the monomer, a step of cooling the dip solution, and a substrate from the dip solution And removing it.

  First, a core-shell type metal nanoparticle having a diameter of about 2 to 3 nm, for example, having an undecenethiol shell having a double bond and an Au core is prepared. Then, a methacrylate having a double bond and a derivative of an azo compound as a radical polymerization initiator are added to a solution obtained by dissolving the metal nanoparticles in a solvent such as toluene. This solution becomes the dip solution.

  Next, after sufficiently stirring this dip solution, for example, a glass substrate whose surface has been cleaned is immersed. And a solution is heated to the temperature of about 30-80 degreeC in the state which dipped the glass substrate. This heating causes an addition polymerization reaction between undecene thiol and methacrylate. Then, it is allowed to cool to room temperature.

  In this way, a nanoparticle thin film in which metal nanoparticles are connected to each other is formed by an addition polymerization reaction of a shell organic material having a double bond and a monomer having a double bond. According to this nanoparticle thin film, the nanoparticle-derived particles have a three-dimensional network structure, so even with a nanometer as small as several nanometers, the adhesion to the substrate and the bonding between the nanoparticles become strong, It is possible to form a thicker film than before. Further, since the particles are bonded to each other by the monomer-derived structural portion, the distance between the particles can be made finer than a material in which nanoparticles are dispersed using a conventional polymer as a binder, and a high-density nanoparticle thin film can be formed. Therefore, it is a film | membrane which has a structure suitable especially when performing fine patterning to a nanoparticle thin film.

  The film thickness of the nanoparticle thin film is not particularly limited, but is preferably 50 nm or more from the viewpoint of application to a near-field light device or a metal circuit wiring.

  In the present embodiment, the core-shell type nanoparticles in which the core metal is gold (Au) and the shell organic substance is undecene thiol have been described as an example. However, the metal of the core is not necessarily limited to gold, and may be, for example, silver (Ag). Further, the organic material of the shell is not necessarily limited to undecene thiol as long as it is an organic material having a double bond, and may be, for example, a derivative of undecene thiol.

  Also, methacrylate has been described as an example of a monomer having a double bond. However, as long as it is a monomer having a double bond, it is not necessarily a methacrylate and may be a derivative of methacrylate, for example.

  The substrate has been described by taking glass as an example. From an economic point of view, glass or silicon is desirable, but for example, a specific plastic or compound semiconductor that is hardly soluble in an organic solvent may be used.

(Second Embodiment)
A nanoparticle thin film pattern forming method according to a second embodiment of the present invention includes a step of forming a metal layer on a substrate, a step of forming a resist pattern on the metal layer, and a metal layer using the resist pattern as a mask. An etching step, a resist pattern peeling step, a nanoparticle thin film forming step on the substrate, and a step of selectively removing the nanoparticle thin film on the surface of the metal layer by ultrasonic waves.

  FIG. 2 is a process cross-sectional view illustrating the nanoparticle thin film pattern forming method of the present embodiment. First, as shown in FIG. 2A, for example, a glass substrate 20 is prepared. Here, it is desirable to clean the surface of the glass substrate 20 with a cleaning liquid composed of hydrogen peroxide and sulfuric acid to ensure a clean surface.

  Then, for example, gold (Au) is deposited on the substrate 20 as the metal layer 22. Here, even if Au is directly deposited on the glass surface up to about 100 to 200 nm, it is unlikely to be peeled off during the subsequent etching process or development process, but if the Au film thickness is further increased, it may peel off from the substrate. Increases nature. In this case, it is desirable to deposit one layer of chromium, titanium or the like on the substrate 20 and then deposit Au on the layer. In this case, a step of etching chromium or titanium in a later process is required. In the present embodiment, for example, it is assumed that the film thickness of gold is about 40 nm, so that chromium or titanium is not used.

  After Au is deposited on the substrate 20 as a metal layer 22, a resist 24 is applied thereon as shown in FIG. 2 (b). The thickness of the resist 24 is not particularly limited. Here, for example, spin coating is performed so as to be 1 μm. It is desired to adjust the spin coat and resist viscosity so that the resist film thickness does not become extremely large.

  Next, as shown in FIG. 2C, after applying the resist 24, exposure is performed using a reticle 26 to form a desired resist pattern. After the resist pattern is formed, it is post-baked and immersed in a developer. Paddling is performed when immersed in the developer.

  As shown in FIG. 2D, after the pattern of the resist 24 is formed, as shown in FIG. 2E, the exposed Au portion is etched using an Au etching solution using the resist pattern as a mask. . The etching solution used at this time is not particularly limited. For example, an etching solution made of iron ions can be employed. In addition, iodine-based solutions and mixed acids may be used.

  After the pattern formation is completed on the metal layer 22, the entire surface is exposed and developed, and the remaining resist pattern is peeled off as shown in FIG. Thus, an Au pattern is formed. Here, Au has been described as an example of the metal layer 22, but is not limited thereto. Any metal can be used as long as an appropriate etching solution can be selected. It is necessary to select an optimal combination in consideration of metal residue and partial precipitation of the etching solution. In addition, by constructing an appropriate recovery system, the entire amount of metal can be recovered and reused.

  Next, as shown in FIG. 2G, nanoparticles are filled in the concave pattern of the produced metal layer 22. This is performed by forming the nanoparticle thin film 30 on the substrate 20. Here, the nanoparticle thin film 30 is formed using the same method as described in the manufacturing method of the first embodiment. Therefore, detailed description of the film forming method is omitted.

  Next, as shown in FIG. 2 (h), the nanoparticle thin film on the surface of the metal layer 22 is selectively removed by ultrasonic treatment in ion-exchanged water. Next, as shown in FIG. 2 (i), only Au is selectively removed in an etching solution, and a pattern composed of the nanoparticle thin film 30 is formed on the substrate 20.

  In this way, for example, a fine nanoparticle thin film pattern with a line width of 5 μm or less can be formed on the substrate.

  Here, as a method for filling the concave portion of the pattern of the metal layer 22 with nanoparticles, the tertiary particles shown in the first embodiment are reacted with acrylate molecules to form tertiary layers via acrylate-derived structural portions. The method of forming the original network structure was used. This method is desirable from the viewpoint of good adhesion to the substrate and easy thickening. Moreover, this method is also desirable from the viewpoint that the nanoparticle thin film 30 is not easily broken in the ultrasonic treatment process.

  However, even if this method is not necessarily used, other methods can be used as long as the method is a method in which nanoparticles are dispersed or dissolved in an organic solvent or water. For example, a method in which a solution in which nanoparticles are dissolved is dropped and dried can be applied, and this method is the simplest.

  Next, a modified example of the present embodiment will be briefly described. In this modification, after the nanoparticle thin film pattern is formed on the substrate by the method described above, an oxide is formed on the nanoparticle thin film, a resist pattern is formed on the oxide, and the resist pattern. And a mask to selectively expose a part of the nanoparticle thin film.

  In this modification, it is possible to form a structure in which the nanoparticle thin film is protected by the protective film on the upper layer, and the nanoparticle thin film is exposed only at a location necessary for device fabrication.

(Third embodiment)
The nanoparticle thin film pattern forming method of the present embodiment is a method of forming a structure in which a pattern is formed of both a metal layer and a nanoparticle thin film on a substrate. Since the material selection of the substrate, the material selection of the metal layer, the film formation method of the nanoparticle thin film, and the like are the same as those in the second embodiment, description thereof is omitted.

  FIG. 3 is a process cross-sectional view illustrating the nanoparticle thin film pattern forming method of the present embodiment. First, as shown in FIG. 3A, for example, a glass substrate 20 is prepared. Here, it is desirable to clean the surface of the glass substrate 20 with a cleaning liquid composed of hydrogen peroxide and sulfuric acid to ensure a clean surface. And after apply | coating the resist 24 on the board | substrate 20, the exposure using a reticle is performed and a resist pattern is formed.

  Next, an Au metal layer 22 is deposited as shown in FIG. Next, as shown in FIG. 3C, the resist 24 is peeled off, and the metal layer 22 portion on the resist is lifted off and peeled off.

  Next, as shown in FIG. 3D, a second metal layer 34 made of Al is deposited on the entire surface. Thereafter, as shown in FIG. 3E, after applying a resist 24, exposure using a reticle is performed to form a second resist pattern.

  Next, as shown in FIG. 3F, the second metal layer 34 made of Al is etched by wet etching, for example, using the second resist pattern as a mask. Thereafter, the Au metal layer 22 is further etched by wet etching, for example.

  Next, the resist is removed as shown in FIG. Next, the nanoparticle thin film 30 is formed as shown in FIG. Next, as shown in FIG. 3I, an ultrasonic wave is applied in an etching solution of Al to selectively remove the nanoparticle thin film 30 on the surface of the second metal layer 34, and the first made of Al. The second metal layer 34 is etched.

  In this way, it is possible to form a structure in which a pattern is formed by both the metal layer and the nanoparticle thin film on the substrate. Such a structure can be applied to, for example, a switching element that uses a nanoparticle thin film portion as a high resistance body.

(Fourth embodiment)
The circuit pattern forming method of the present embodiment includes a step of forming a metal layer on a substrate, a step of forming a resist pattern on the metal layer, a step of etching the metal layer using the resist pattern as a mask, and a resist pattern A step of forming a nanoparticle thin film on the substrate, a step of selectively removing the nanoparticle thin film on the surface of the metal layer by ultrasonic waves, and a step of selectively removing the nanoparticle thin film on the surface of the metal layer. After the step of removing, the step of etching the metal layer and the step of metallizing the nanoparticle thin film by heating the substrate to 130 ° C. or higher are included. Here, since the process up to the step of etching the metal layer is the same as that of the second embodiment, the description of the overlapping contents is omitted.

  FIG. 4 is a process sectional view showing the circuit pattern forming method of the present embodiment. Since the processes shown in FIGS. 4A to 4I are the same as the processes shown in FIGS. 2A to 2I, description thereof is omitted.

  As shown in FIG. 4 (j), for example, after a pattern made of the nanoparticle thin film 30 is formed on a glass substrate 20, the pattern on the substrate is formed in an oven at a temperature of about 130 ° C. to 250 ° C. Heat for 10 hours. By this heat treatment, the nanoparticle thin film 30 is metallized, and the nanoparticle thin film pattern is changed to the metal pattern 40.

  According to the present embodiment, it is possible to form a circuit pattern of fine metal wiring.

  The embodiments of the present invention have been described above with reference to specific examples. In the description of the embodiment, the description of the parts that are not directly necessary for the description of the present invention is omitted in the nanoparticle thin film, the nanoparticle thin film manufacturing method, the nanoparticle thin film pattern forming method, the circuit pattern forming method, and the like. However, the elements involved in the required nanoparticle thin film, nanoparticle thin film production method, nanoparticle thin film pattern formation method, circuit pattern formation method, and the like can be appropriately selected and used.

  In addition, all nanoparticle thin films, nanoparticle thin film manufacturing methods, nanoparticle thin film pattern forming methods, and circuit pattern forming methods that include elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention. Is done. The scope of the present invention is defined by the appended claims and equivalents thereof.

  Examples of the present invention will be described in detail below.

Example 1
The nanoparticle thin film manufacturing method of the first embodiment was applied to the nanoparticle thin film pattern forming method of the second embodiment shown in FIG. 2 to perform pattern formation.

  11-bromo-1-undecene (Wako Pure Chemical Industries), thiourea (Wako Pure Chemical Industries), and ethanol (Wako Pure Chemical Industries) were prepared. 11-Bromo-1-undecene 50 mmol and thiourea 50 mmol were dissolved in 30 ml of ethanol and refluxed for 4 hours. After the reflux, 75 mmol / 30 ml of an aqueous sodium hydroxide solution was added, and the reflux was further continued for 2 hours. After separating the organic layer and removing the solvent with an evaporator, white solid 11-undecenethiol was recovered.

  6 mmol of tetraoctylammonium bromide (abbreviated as TOAB, Wako Pure Chemical Industries) was added to 100 ml of toluene. A solution prepared by dissolving 1 g of tetrachloroauric acid in 60 ml of water was added to the toluene solution, and the mixture was forcibly stirred. To this, 0.56 g of 11-undecenethiol was dissolved in 20 ml of toluene and added. After stirring for about 10 minutes, 30 mmol of sodium borohydride (Kanto Chemical) was added. After 6 hours, liquid separation was performed to remove the organic layer and reprecipitation into methanol. A black solid was obtained. This black solid was redissolved in toluene and a grid type TEM was measured. It was confirmed that nanoparticles having an average particle size of 2 to 3 nm (average particle size of 2.5 nm) were produced.

  A 20 mm square glass substrate was immersed in a solution of 30% hydrogen peroxide and concentrated sulfuric acid mixed 3 to 7. The surface was rinsed with ion-exchanged water, and then rinsed with ethanol. On this glass substrate, gold (Au) having a film thickness of 40 nm was deposited on one side. An I-line resist (THMR-iP5720HP) was applied to the evaporated Au surface with a spin coater at 4000 rpm for 30 seconds. After post-baking at 90 degrees for 90 seconds, a patterned reticle was brought into close contact with the chrome surface, and exposure at 50 mJ / cm 2 was performed. After post-baking was performed at 110 degrees for 90 seconds, development processing was performed with NMD-W 2.38% solution for 60 seconds.

  A solution composed of 20 mM iron nitrate and 30 mM thiourea was prepared, and the Au portion exposed by development was etched for 7 minutes. After the etching, the substrate was washed with ion exchange water, and water droplets on the surface were removed by air jet. In order to peel off the remaining resist, exposure was performed for 12 seconds and development was performed. Au remained patterned on the substrate, and only the resist was peeled off. A 4 μm wide wiring pattern of 4 μm width of the Au film was formed.

  0.1 g of nanoparticles (UDE-AUNP) having a particle size of 2.5 nm in which the black solid, undecenethiol, was placed in 10 ml of toluene was dissolved. Normal type dodecyl methacrylate (Tokyo Chemical Industry) 0.5g was added. A solution prepared by dissolving 0.1 g of 2,2′-azobisisobutyronitrile (abbreviation: AIBN, Wako Pure Chemical), which is a polymerization initiator, in 10 ml of toluene was prepared and added to the solution. After sufficiently stirring, the substrate that had been subjected to the patterning treatment was immersed in this solution. The substrate was installed in a state of being vertical to the ground. The reaction was carried out at 80 degrees for 4 hours, and then allowed to cool to room temperature. It was left as it was for 12 hours.

  After removing the substrate from the solution, the nanoparticle film on the Au surface was selectively removed by applying ultrasonic waves while being immersed in ion-exchanged water. A solution composed of 20 mM iron nitrate and 30 mM thiourea was prepared, and the exposed Au film was etched. A 4 μm wide line pattern was formed by the nanoparticle film. The thickest part was 0.93 μm.

(Example 2)
Pattern formation was carried out in the same manner as in Example 1 except that the polymerization initiator was 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (abbreviation V-70, Wako Pure Chemical Industries). Went.

  A 4 μm wide line pattern was formed by the nanoparticle film. The thickest part was 1.13 μm.

(Example 3)
A nanoparticle thin film manufacturing method in which a solution in which nanoparticles were dissolved was dropped and dried was applied to the nanoparticle thin film pattern forming method of the second embodiment shown in FIG. 2 to perform pattern formation.

  6 mmol of tetraoctylammonium bromide (abbreviated as TOAB, Wako Pure Chemical Industries) was added to 100 ml of toluene. A solution prepared by dissolving 1 g of tetrachloroauric acid in 60 ml of water was added to the toluene solution, and the mixture was forcibly stirred. To this, 0.61 g of 1-dodecanethiol was dissolved in 20 ml of toluene and added. After stirring for about 10 minutes, 30 mmol of sodium borohydride (Kanto Chemical) was added. After 6 hours, liquid separation was performed to remove the organic layer and reprecipitation into methanol. A black solid (C12-AuNP) was obtained. This black solid was redissolved in toluene and a grid type TEM was measured. It was confirmed that nanoparticles having an average particle size of 2 to 3 nm (average particle size of 2.3 nm) were produced.

  A 20 mm square glass substrate was immersed in a solution of 30% hydrogen peroxide and concentrated sulfuric acid mixed 3 to 7. The surface was rinsed with ion-exchanged water, and then rinsed with ethanol. On this glass substrate, gold (Au) having a film thickness of 40 nm was deposited on one side. An I-line resist (THMR-iP5720HP) was applied to the evaporated Au surface with a spin coater at 4000 rpm for 30 seconds. After post-baking at 90 degrees for 90 seconds, a patterned reticle was brought into close contact with the chrome surface and exposed at 60 mJ / cm 2. After post-baking was performed at 110 degrees for 90 seconds, development processing was performed with NMD-W 2.38% solution for 60 seconds.

  A solution composed of 20 mM iron nitrate and 30 mM thiourea was prepared, and the Au portion exposed by development was etched for 7 minutes. After the etching, the substrate was washed with ion exchange water, and water droplets on the surface were removed by air jet. In order to peel off the remaining resist, exposure was performed for 12 seconds and development was performed. Au remained patterned on the substrate, and only the resist was peeled off. A 4 μm wide wiring pattern of Au film was formed.

  0.01 g of the black solid (C12-AuNP) was dissolved in 1 ml of toluene. This was dropped on the wiring pattern, and the substrate was dried on a hot plate at 40 degrees for 1 hour to form a film. The film on the Au surface was selectively removed by applying ultrasonic waves in a state of being immersed in ion-exchanged water. A solution composed of 20 mM iron nitrate and 30 mM thiourea was prepared, and the exposed Au film was etched. A 4 μm wide line pattern was formed by the nanoparticle film. The pattern was broken in some places. It was also observed that the Au film residue remained on the substrate surface.

Example 4
Pattern formation is performed in the same manner as in Example 3 except that water-dispersed nanoparticles (Tanaka Kikinzoku, Au-MSA colloid solution 1.5 wt%) are dropped instead of the solution in which the black solid (C12-AuNP) is dissolved. went.

  A 4 μm wide line pattern was formed by the nanoparticle film. The pattern was broken in some places. It was also observed that the Au film residue remained on the substrate surface.

(Example 5)
The manufacturing method of the nanoparticle thin film of 1st Embodiment was applied to the nanoparticle thin film pattern formation method of 3rd Embodiment shown in FIG. 3, and pattern formation was performed. The nanoparticle thin film was produced under the same conditions as in Example 1. This will be described with reference to FIGS. 5 and 6 are plan views for explaining the nanoparticle thin film pattern forming method of this embodiment. FIGS. 7A and 7B are a plan view and a cross-sectional view, respectively, of the nanoparticle thin film pattern formed in this example.

  As shown in FIG. 5, the resist 24 was apply | coated on the glass substrate. The pattern was exposed to remove the resist 24 in the shaded area 50 in FIG. In this state, post-baking was performed at 110 degrees for 90 seconds, and Au was deposited to 40 nm in a vacuum chamber. Next, as shown in FIG. 6, the resist was peeled off, the Au film on the resist was lifted off, and an Au pattern 22 was formed on the substrate 20.

  Thereafter, Al was deposited on the entire surface of the substrate by 10 nm. Further, a resist was applied on the entire surface of the substrate. Development was performed after aligning and exposing the mask so that a portion corresponding to the pattern 52 (FIG. 6) surrounded by the broken line of the Au pattern 22 was exposed. A part of Al was also dissolved during development. The residue was etched with an Al etching solution (special Al etching solution, Kanto Chemical Co., Inc.), and then the pattern 52 portion of the Au film was etched with a solution of 20 mM iron nitrate and 30 mM thiourea.

  After the resist was exposed and peeled from the entire surface, a thin film was formed on the substrate having the Au pattern 22 by reacting UDE-AuNP and normal type dodecyl methacrylate with a radical initiator by the method of Example 1. The Al film deposited on the entire surface was etched with an etching solution while applying ultrasonic waves. As shown in FIG. 7, a structure in which a pattern is formed by both the Au pattern 22 and the nanoparticle thin film 30 was formed on the substrate 20.

(Example 6)
A nanoparticle thin film pattern was formed under the same conditions as in Example 1 except that the nanoparticle thin film pattern was a straight line having a width of 8 μm and a thickness of 10 nm, and a protective film was formed on the formed nanoparticle thin film pattern. The protective film is formed by the following process. First, 200 nm of oxide calcium oxide was deposited on the line pattern of the nanoparticle thin film. Further, a resist was applied, and a circular pattern having a diameter of 4 μm was aligned and exposed so as to overlap two ends of the line. After development, it was thoroughly washed with ion exchange water. Development and cleaning with ion-exchanged water totaled 60 seconds. Thereafter, the oxide in the circular pattern portion was removed by etching, and then the resist was peeled off.

  FIG. 8 is a cross-sectional view of a nanoparticle thin film pattern formed according to this example. As shown in the figure, a straight line of a nanoparticle thin film 30 is formed on a glass substrate 20, and a protective film 60 of calcium oxide is formed thereon. An opening 70 for inputting / outputting a signal is formed at a portion corresponding to the straight line end of the protective film 60.

(Example 7)
The 4 μm-wide nanoparticle thin film pattern formed in Example 1 was heated in an oven at 250 ° C. for 2 hours. The same pattern was heated at 130 ° C. for 24 hours, 180 ° C. for 15 hours, and 210 ° C. for 8 hours. Under all conditions, a metal wiring circuit pattern was formed.

(Example 8)
The nanoparticle thin film manufacturing method of the first embodiment was applied to the nanoparticle thin film pattern forming method of the second embodiment shown in FIG. 2 to perform pattern formation. Unlike Example 1, a chromium (Cr) film was formed between a glass substrate and Au to improve adhesion.

A 20 mm square glass substrate was immersed in a solution of 30% hydrogen peroxide and concentrated sulfuric acid mixed 3 to 7. The surface was rinsed with ion-exchanged water, and then rinsed with ethanol. Chromium with a thickness of 10 nm was vapor-deposited on this glass substrate, and then gold (Au) with a thickness of 100 nm was vapor-deposited. An I-line resist (THMR-iP5720HP) was applied to the evaporated Au surface with a spin coater at 4000 rpm for 30 seconds. After post-baking at 90 degrees for 90 seconds, a patterned reticle was brought into close contact with the chrome surface and exposed at 60 mJ / cm ² . After post-baking was performed at 110 degrees for 90 seconds, development processing was performed with NMD-W 2.38% solution for 60 seconds. A solution composed of 20 mM iron nitrate and 30 mM thiourea was prepared, and the Au portion exposed by development was etched for 7 minutes. After the etching, the substrate was washed with ion exchange water, and water droplets on the surface were removed by air jet.

  Next, Cr was etched with a Cr etching solution (Cr-01N, Kanto Chemical). In order to peel off the remaining resist, exposure was performed for 12 seconds and development was performed. Au remained patterned on the substrate, and only the resist was peeled off. An Au film wiring pattern having a width of 4 μm was formed. Using this substrate, 0.1 g of nanoparticles (UDE-AUNP) in which undecene thiol, which is a black solid described in Example 1, was placed in 10 ml of toluene was dissolved. Normal type dodecyl methacrylate (Tokyo Chemical Industry) 0.5g was added. A solution in which 0.1 g of α, α'-azobisisobutyronitrile (abbreviation AIBN, Wako Pure Chemical Industries, Ltd.) was dissolved in 10 ml of toluene was prepared and added to the solution. After sufficiently stirring, the substrate subjected to the patterning treatment was immersed in this solution. The substrate was installed in a state of being vertical to the ground. The reaction was carried out at 80 degrees for 4 hours, and then allowed to cool to room temperature. It was left as it was for 12 hours.

  After removing the substrate from the solution, the film on the Au surface was selectively removed by applying ultrasonic waves while immersed in ion-exchanged water. The above Au etching solution was prepared, and the exposed Au film was etched. Next, the Cr etching solution was prepared and Cr was etched. A pattern line 4 μm wide was formed by the nanoparticle film. A 4 μm wide line pattern was formed by the nanoparticle film. The thickest part was 0.92 μm.

(Comparative example)
As a comparative example, a nanoparticle thin film was manufactured using a method in which a silane coupling agent was previously applied to the substrate surface.

  First, a 20 mm square glass substrate was immersed in a solution of 30% hydrogen peroxide and concentrated sulfuric acid mixed 3 to 7. The surface was rinsed with ion-exchanged water, and then rinsed with ethanol. A 0.1 M toluene solution of octyltrichlorosilane (Kanto Chemical), 3- [tris (trimethylsilyloxy) silyl] propyl methacrylate (Tokyo Kasei) and 3-mercaptopropyltrimethoxysilane (Kanto Chemical) was prepared. The substrate was immersed in each of the above solutions and allowed to stand at 60 degrees for 30 minutes. The substrate was washed with methanol and then dried.

  The C12-AuNP 0.01 g / 10 ml toluene solution used in Example 3 was applied to this substrate, and a thin film was produced by spin coating at 1500 rpm for 60 s. In the substrate coated with octyltrichlorosilane, an infinite number of C12-AuNP aggregates of about 1 to 10 μm were observed on the entire surface of the substrate. On the substrate coated with 3- [tris (trimethylsilyloxy) silyl] propyl methacrylate, thin film unevenness of several hundred μm to several mm was visually observed, and phase separation of 1 to 3 μm was observed when magnified with a microscope. On the substrate coated with 3-mercaptopropyltrimethoxysilane, aggregates of C12-AuNP were observed in several places. Under any of the conditions, a good thin film having a uniform thickness and a high thickness was not formed.

  As mentioned above, the effect | action and effect of this invention were confirmed by the Example and the comparative example.

The conceptual diagram of the nanoparticle cross-section of 1st Embodiment. Process sectional drawing which shows the nanoparticle thin film pattern formation method of 2nd Embodiment. Process sectional drawing which shows the nanoparticle thin film pattern formation method of 3rd Embodiment. Process sectional drawing which shows the circuit pattern formation method of 4th Embodiment. FIG. 6 is a plan view for explaining a nanoparticle thin film pattern forming method of Example 5. FIG. 6 is a plan view for explaining a nanoparticle thin film pattern forming method of Example 5. 6 is a plan view and a cross-sectional view of a nanoparticle thin film pattern formed in Example 5. FIG. 6 is a cross-sectional view of a nanoparticle thin film pattern formed in Example 6. FIG.

Explanation of symbols

10, 20 Substrate 12 Metal nanoparticle-derived particle 14 Monomer-derived structural portion 16 Organic substance 22 Metal layer 24 Resist 26 Reticle 30 Nanoparticle thin film 34 Second metal layer 40 Metal pattern 60 Protective film 70 Opening

Claims (9)

A core-shell type nanoparticle formed by a shell of an organic substance having a double bond and a metal core is a nanoparticle thin film formed by chemically bonding with a monomer having a double bond,
A nanoparticle thin film characterized in that particles derived from the nanoparticles are bonded via a structural portion derived from the monomer to form a three-dimensional network structure. The organic substance is undecene thiol or a derivative thereof, and
The nanoparticle thin film according to claim 1, wherein the monomer is methacrylate or a derivative thereof.   3. The nanoparticle thin film according to claim 1, comprising a radical polymerization initiator, α, α′-azobisisobutyronitrile, bis (cyclohexylsulfonyl) diazomethane, or a derivative of an azo compound. 4.   The nanoparticle thin film according to any one of claims 1 to 3, wherein the film thickness is 50 nm or more. A step of preparing a dip solution by dissolving a core-shell type nanoparticle formed of a shell of an organic substance having a double bond and a metal core, a monomer having a double bond, and a radical polymerization initiator in a solvent;
Immersing the substrate in the dip solution;
Heating the dip solution in which the substrate is immersed, and reacting the organic substance with the monomer;
Cooling the dip solution;
And a step of removing the substrate from the dipping solution and cleaning the substrate. The organic substance is undecene thiol or a derivative thereof, and
The monomer is methacrylate or a derivative thereof, and
6. The method for producing a nanoparticle thin film according to claim 5, wherein the radical polymerization initiator is α, α′-azobisisobutyronitrile, bis (cyclohexylsulfonyl) diazomethane, or a derivative of an azo compound. Forming a metal layer on the substrate;
Forming a resist pattern on the metal layer;
Etching the metal layer using the resist pattern as a mask;
Removing the resist pattern;
Forming a nanoparticle thin film on the substrate;
By ultrasonic, it has a step of selectively removing the nanoparticle thin film of the metal layer surface,
Forming the nanoparticle thin film on the substrate,
A step of preparing a dip solution by dissolving a core-shell type nanoparticle formed of a shell of an organic substance having a double bond and a metal core, a monomer having a double bond, and a radical polymerization initiator in a solvent;
Immersing the substrate in the dip solution;
Heating the dip solution in which the substrate is immersed, and reacting the organic substance with the monomer;
Cooling the dip solution;
Nanoparticle thin film pattern forming method, which comprises organic and washing was taken out the substrate from the dipping solution. After the step of selectively removing the nanoparticle thin film on the surface of the metal layer by ultrasonic waves,
Etching the metal layer;
Forming an oxide on the nanoparticle thin film;
Forming a resist pattern on the oxide;
8. The method of forming a nanoparticle thin film pattern according to claim 7, further comprising a step of selectively exposing a part of the nanoparticle thin film by etching the oxide using the resist pattern as a mask. Forming a metal layer on the substrate;
Forming a resist pattern on the metal layer;
Etching the metal layer using the resist pattern as a mask;
Removing the resist pattern;
Forming a nanoparticle thin film on the substrate;
A step of selectively removing the nanoparticle thin film on the surface of the metal layer by ultrasonic;
Etching the metal layer after the step of selectively removing the nanoparticle thin film on the surface of the metal layer;
Have a step of metallizing the nanoparticle thin film by heating the substrate above 130 ° C.,
Forming the nanoparticle thin film on the substrate,
A step of preparing a dip solution by dissolving a core-shell type nanoparticle formed of a shell of an organic substance having a double bond and a metal core, a monomer having a double bond, and a radical polymerization initiator in a solvent;
Immersing the substrate in the dip solution;
Heating the dip solution in which the substrate is immersed, and reacting the organic substance with the monomer;
Cooling the dip solution;
Circuit pattern forming method characterized by chromatic and washing was taken out the substrate from the dipping solution.

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