JP2010080865A - METHOD OF MANUFACTURING STAMP FOR MICRO CONTACT PRINTING (muCP) - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a stamp for μCP (micro contact printing) using PDMS (polydimethyl siloxane), manufacturing the stamp for μCP almost completely preventing mixing of bubbles and performing uniform pattern printing. <P>SOLUTION: The above problem is solved by providing the method of manufacturing the stamp for μCP including the steps of using a master plate with a fine rugged pattern formed on its surface and applying a PDMS film on the master plate, using a substrate and adhering the substrate onto the applied PDMS film and releasing the PDMS film and the substrate from the master plate. At the adhering step, a speed at which the PDMS film is brought into contact with the substrate is not more than 5 μm/s. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a microcontact printing stamp (μCP stamp) used in a microcontact printing (μCP) method.

  Among various ultra-fine processes that can be used as patterning techniques for microstructures and nanostructures, soft lithography is employed in many studies. “Soft lithography” is a patterning technique that uses a pattern elastomer, a template or a mask as a stamp to create a micropattern, microstructure or nanopattern, or nanostructure. Examples of such soft lithography include micro contact printing, replication molding, ultra-fine transfer molding, ultra-fine molding using capillary phenomenon, ultra-fine molding using a solvent, phase shift photolithography, casting molding, emboss molding, injection molding. However, in recent years, since it is possible to print nano-order fine patterns with high accuracy, it is considered to use the micro-contact printing method in semiconductor device manufacturing methods, etc. Has been.

  Here, the microcontact printing (μCP) method is a method of G. M.M. This is a fine patterning technology developed by Whitesides et al. “Plate”, which is a pattern made by photolithography on a silicon or quartz substrate and mastered with silicone rubber called polydimethylsiloxane (heat-curing PDMS) Is a technique for printing a fine pattern up to several tens of nanometers in size. Such a μCP method is disclosed in, for example, Patent Documents 1 and 2.

JP 2002-206033 A JP 2002-353436 A

  By the way, in micro contact printing (μCP), printing is performed in the same pattern as the stamp used. Therefore, in order to perform a desired pattern printing by the μCP method, a stamp having the pattern is accurately used. Manufacturing is indispensable. The μCP stamp used in the μCP method is generally manufactured by the following method. First, using a master plate on which a predetermined fine concavo-convex pattern is formed, an application step of applying an elastomer such as PDMS (polydimethylsiloxane) on the master plate, and using an arbitrary substrate, the substrate is applied as described above. A PDMS layer in which a pattern having a shape in which the concave and convex shape of the master plate is reversed is formed on the substrate by an adhesion process for bonding onto the elastomer film and a peeling process for peeling the PDMS film from the master plate. A method of manufacturing the formed μCP stamp is used. According to such a method, the stamp for μCP on which nano-order fine irregularities are formed can be manufactured by a relatively simple process.

  A method of manufacturing such a μCP stamp will be described with reference to the drawings. FIG. 2 is a schematic view showing an example of a method for manufacturing the above-described μCP stamp. As illustrated in FIG. 2, a μCP stamp usually uses a master plate 200 on which a predetermined fine concavo-convex pattern is formed (FIG. 2A), and PDMS (polydimethylsiloxane) is formed on the master plate 200. An application step of applying an elastomer such as (FIG. 2B), an adhesion step of bonding the substrate 102 onto the applied elastomer film 101 using an arbitrary substrate 102 (FIG. 2C), A PDMS layer in which a concavo-convex pattern in which the concavo-convex shape of the master plate is reversed is formed on the surface of the substrate 102 by a peeling step of peeling the PDMS film 101 and the substrate 102 from the master plate 200 (FIG. 2D). A method of manufacturing the μCP stamp 100 in which the 101 is formed is used (FIG. 2E).

  Here, a substrate having a smooth surface is usually used as the substrate (flat plate-flat plate method).

  However, when the μCP stamp is manufactured by the above method, there is a problem that bubbles are mixed between the substrate and the PDMS film when the substrate and the PDMS film are brought into contact in the bonding step. .

  Such problems will be described with reference to the drawings. FIG. 3 is a schematic diagram for explaining the problem of the bubble mixing. As illustrated in FIG. 3, in the μCP stamp manufacturing method as described above, the substrate 102 and the coated elastomer film 101 applied on the master plate 200 are bonded in the bonding step (FIG. 3A )) At this time, there is a problem in that bubbles X are mixed between the elastomer film 101 and the substrate 102 (FIG. 3B).

  Such a problem of air bubble mixing is particularly a problem in the flat plate method using a flat plate as the substrate.

  When bubbles are mixed between the substrate and the PDMS film in this way, the uneven pattern is lost in the manufactured μCP stamp, or bubbles are generated when pattern printing is performed using the μCP stamp. Pressure distribution occurs between the part where the ink is present and the part where it is not, making it difficult to print uniformly according to the pattern of the stamp, or even applying ink to the stamp (inking). There is a problem that a difference in the amount of ink to be generated occurs between a portion where bubbles are present and a portion where bubbles are not present, and as a result, uniform pattern printing becomes difficult. The problem of such bubble mixing becomes more prominent as the uneven shape formed on the PDMS film becomes finer, especially when nano-order uneven shapes are imparted to PDMS. However, the problem is that it induces the above problems.

  The present invention has been made in view of such problems, and is a method for manufacturing a stamp for μCP using PDMS, which can almost completely prevent air bubbles from being mixed in a homogeneous manner. It is a main object of the present invention to provide a μCP stamp manufacturing method capable of manufacturing a μCP stamp capable of performing pattern printing.

  In order to solve the above-mentioned problems, the present invention uses a master plate having a fine concavo-convex pattern formed on the surface, a coating step of coating PDMS on the master plate, and a substrate, on the coated PDMS film. A method for manufacturing a stamp for μCP, which includes an adhesion step for adhering the substrate and a separation step for separating the PDMS film and the substrate from the master plate, wherein the PDMS film and the substrate are contacted in the adhesion step. Provided is a method for producing a stamp for μCP, characterized in that the forming speed is 5 μm / s or less.

According to the present invention, air bubbles are mixed between the PDMS film and the substrate when the contact speed when the substrate and the PDMS film are brought into contact with each other in the bonding step is 5 μm / s or less. Can be almost completely prevented.
For this reason, according to the present invention, a stamp for μCP capable of performing uniform pattern printing can be manufactured.

  In the present invention, the contact speed is preferably in the range of 0.01 μm / s to 1 μm / s. This is because, when the contact speed is within such a range, the possibility of bubbles being mixed between the PDMS film and the substrate in the bonding step can be further reduced.

  The μCP stamp manufacturing method of the present invention can produce a μCP stamp capable of manufacturing a μCP stamp capable of performing pattern printing in a homogeneous manner.

  Hereinafter, the manufacturing method of the stamp for μCP of the present invention will be described.

  As described above, the manufacturing method of the stamp for μCP of the present invention uses the master plate having the fine uneven pattern formed on the surface, the coating step of applying PDMS on the master plate, and the coating using the substrate. An adhesion process for adhering the substrate onto the PDMS film, and an exfoliation process for exfoliating the PDMS film and the substrate from the master plate, wherein the PDMS film and the substrate are contacted in the adhesion process. It is characterized in that the speed to be applied is 5 μm / s or less.

A method for manufacturing the μCP stamp of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an example of a method for producing a μCP stamp of the present invention. As illustrated in FIG. 1, the μCP stamp manufacturing method of the present invention uses a master plate 20 having a fine concavo-convex pattern formed on the surface (FIG. 1A), and a PDMS film on the master plate 20. 1 (FIG. 1B), a bonding step of bonding the substrate 2 on the applied PDMS film 1 using the substrate 2 (FIG. 1C), and the master plate 20 And a step of peeling the PDMS film 1 and the substrate 2 from each other (FIG. 1D), and the μCP stamp 10 having the PDMS film 1 having a concavo-convex shape formed on the surface thereof on the substrate 2. Is to be manufactured.
In such an example, the μCP stamp manufacturing method of the present invention is characterized in that the speed at which the PDMS film 1 and the substrate 2 are brought into contact in the bonding step is 5 μm / s or less.

According to the present invention, air bubbles are mixed between the PDMS film and the substrate when the contact speed when the substrate and the PDMS film are brought into contact with each other in the bonding step is 5 μm / s or less. Can be almost completely prevented.
Therefore, according to the present invention, the pattern formed on the PDMS film is lost, or when the pattern printing is performed using the μCP stamp manufactured according to the present invention, the part where the bubble exists and the part where the bubble does not exist Pressure distribution occurs, making it difficult to print uniformly according to the pattern of the stamp, and when ink is applied to the stamp (inking), there are bubbles in the amount of ink applied to the stamp It is possible to prevent a difference between a part and a part that is not so that uniform pattern printing becomes difficult as a result.
For this reason, according to the present invention, it is possible to manufacture a μCP stamp capable of performing uniform pattern printing.

Here, it is not clear why it is possible to almost completely prevent air bubbles from being mixed between the PDMS film and the substrate by setting the contact speed within the above range in the present invention. Although it is not, it is considered to be related to the speed at which PDMS, which is a liquid, contacts the substrate when contacting the substrate.
That is, PDMS as a liquid comes into contact with a solid substrate, and bubbles mixed in PDMS are completely removed by sufficiently slowing down the speed of spreading and contacting, rather than the speed at which bubbles are generated and bubbles escape. It is thought that it was removed. On the other hand, if the speed at which wetting spreads, that is, the contact speed is too fast, the next PDMS spreads before the bubbles escape to the outside, and as a result, it is considered that the bubbles are taken in.

The μCP stamp manufacturing method of the present invention includes at least a coating process, an adhesion process, and a peeling process, and may include other processes as necessary.
Hereafter, each process used for the manufacturing method of the stamp for μCP of the present invention is explained in order.

1. Bonding process First, the bonding process used in the present invention will be described. This step is an adhesion step in which the substrate is adhered onto the PDMS film formed on the master plate in the coating step described later. This step is characterized in that the contact speed at which the PDMS film and the substrate are brought into contact with each other is 5 μm / s or less. The manufacturing method of the stamp for μCP of the present invention can almost completely prevent air bubbles from being mixed between the substrate and the PDMS film because the contact speed in this step is within such a range. As a result, according to the present invention, it is possible to manufacture a μCP stamp capable of performing a uniform pattern printing.

  Thus, this step is characterized in that the contact speed between the substrate and the PDMS film is 5 μm / s or less. In this step, the contact speed is in such a range. This is because if the speed is faster than the above range, the possibility of bubbles being mixed between the substrate and the PDMS film in this step is significantly increased. In other words, the μCP stamp manufacturing method of the present invention has been completed on the basis that it has been found that the possibility of bubbles being mixed is significantly reduced by setting the contact speed in this step within the above range. It can be said that.

Although the said contact speed in this process will not be specifically limited if it is 5 micrometers / s or less, It is preferable to exist in the range of 0.01 micrometer-5 micrometers especially, and it exists in the range of 0.01 micrometer-3 micrometers. Is more preferable, and it is further preferable to be within a range of 0.01 μm to 1 μm.
This is because, when the contact speed is within such a range, in this step, it is possible to further reduce the possibility of bubbles being mixed between the PDMS film and the substrate.

  Here, the contact speed means a speed immediately before the PDMS film and the substrate are brought into contact with each other in the present step. That is, the method for controlling the speed until the substrate and the PDMS film are brought into contact with each other in this step is not particularly limited. For example, a method in which a constant speed is always set may be used, or intermittently. Alternatively, a method of continuously changing the speed may be used, but the contact speed always means a speed immediately before the PDMS film and the substrate are brought into contact with each other.

  In addition, as a method of changing the speed, for example, the substrate and the PDMS film are brought close to each other at a relatively high speed until approaching a certain distance, and then brought close to each other at 5 μm / s or less. Can be mentioned.

In this step, the mode of bringing the substrate into contact with the PDMS film is not particularly limited, and any mode can be used depending on the type of the substrate. Such an embodiment may be an embodiment in which the surface of the substrate and the surface of the PDMS film are kept in contact with each other while maintaining a parallel state, or in a state where both surfaces have a certain angle. It is also possible to adopt the mode. In particular, the former mode is preferably used in this step. By bringing the surface of the substrate and the surface of the PDMS film into contact with each other while maintaining a parallel state, even with a nano-order ultra-fine concavo-convex pattern, a concavo-convex pattern can be formed from the master plate to the PDMS plate with high accuracy. This is because it becomes possible to transfer.
In general, if the surface of the substrate and the surface of the PDMS film are kept in contact with each other while maintaining a parallel state, the probability that bubbles will be mixed between the substrate and the PDMS plate is significantly increased. In the invention, by setting the contact speed in this step within the above-described range, it is possible to almost completely prevent bubbles from being mixed even in the case of contacting by such a method.

  In this step, after the substrate and the PDMS film are brought into contact with each other at the contact speed, the substrate may be pushed toward the PDMS film so that the PDMS film is further compressed by the substrate. This is because, by performing such pushing, even if a small amount of air bubbles are mixed between the substrate and the PDMS film immediately after the substrate is brought into contact with the PDMS film, it can be discharged afterwards. .

  The amount of pressing when the pressing is performed can be appropriately determined according to the thickness of the PDMS film, the area of the μCP stamp to be manufactured, and the like, and is not particularly limited. In particular, the indentation amount in this step is preferably within a range of 10 mm or less, more preferably within a range of 5 mm or less, and even more preferably within a range of 1 mm or less.

  In addition, the indentation speed when the indentation is performed can be appropriately determined according to the thickness of the PDMS film, the area of the stamp for μCP to be manufactured, and the like, and is not particularly limited. In particular, the indentation speed in this step is preferably 5 μm / s or less, preferably in the range of 0.01 μm to 5 μm, and in the range of 0.01 μm to 3 μm, like the contact speed described above. More preferably, it is more preferably in the range of 0.01 μm to 1 μm.

  In this step, after the substrate and the PDMS film are brought into contact with each other, the PDMS film is cured to be bonded to each other. However, the method for curing the PDMS film is not particularly limited. Here, since the PDMS has a property of being cured by heating, the degree of curing depends on temperature and time. Therefore, when it is necessary to cure the PDMS film in a short time, after the PDMS film and the substrate are brought into contact with each other, heat treatment may be performed to promote the curing of the PDMS film. On the other hand, when there is no restriction on the time for curing the PDMS film, it may be left at room temperature.

Next, the board | substrate used for this process is demonstrated. The substrate used in this step can be appropriately determined according to the use of the μCP stamp manufactured according to the present invention, and is not particularly limited. In particular, the substrate used in the present invention preferably has a flat plate shape. By using the substrate having such a shape, it is possible to transfer the concavo-convex pattern from the master plate to the PDMS plate with high accuracy even with a nano-order ultra-fine concavo-convex pattern.
As described above, when a flat plate is used as the substrate, there is a high probability that bubbles will be mixed between the substrate and the PDMS plate. However, in the present invention, the contact speed in this step is set as described above. By setting it within the range, even when such a substrate is used, it is possible to almost completely prevent bubbles from being mixed.

  The substrate used in the present invention preferably has a water contact angle in the range of 5 ° to 45 °, more preferably in the range of 5 ° to 35 °, and in the range of 5 ° to 30 °. More preferably. This is because the possibility that air bubbles are mixed between the substrate and the PDMS film in this step can be further reduced because the contact angle of the substrate with respect to water is within the above range.

The substrate used in this step may be a rigid substrate such as a glass substrate, a Si substrate, or a SiO ₂ substrate, or a flexible flexible film such as a film made of a plastic resin. It may be a substrate. Examples of the plastic resin include PET, PEN, PES, PI, PEEK, PC, PPS, and PEI.

  Further, the substrate used in this step may be subjected to a surface treatment in order to make the contact angle with water within a certain range.

2. Application Step Next, the application step used in the present invention will be described. This step is a step of applying a PDMS film on the master plate using a master plate having a fine uneven pattern formed on the surface.

  The master plate used in this step is not particularly limited as long as a desired uneven pattern that can be transferred to the PDMS film is formed on the surface. Examples of such a master plate include those made of silicon, quartz, photoresist and the like.

  The size of the concavo-convex pattern formed on the master plate is appropriately determined according to the use etc. of the stamp for μCP manufactured by the present invention. Since it can be almost completely eliminated, it is possible to transfer the concavo-convex pattern to the PDMS film with high accuracy even when a master plate having a very small concavo-convex pattern of nano order is used. .

  In this step, PDMS is applied on the surface of the master plate on which the concave / convex pattern is formed. As a method for applying the PDMS in this step, a PDMS film having a smooth surface on the master plate is used. The method is not particularly limited as long as the method can form the film. Examples of such coating methods include spin coating, die coating, roll coating, bar coating, LB, dip coating, spray coating, blade coating, dispenser, and casting. Can do.

3. Peeling process Next, the peeling process used for this invention is demonstrated. This step is a step of peeling the PDMS film and the substrate from the master plate. The method for peeling the PDMS film and the substrate from the master plate in this step is not particularly limited as long as the method can peel the pattern so as not to be lost. As such a method, a method of physically separating the PDMS film from the master plate is usually used.

4). Other Steps In the manufacturing method of the stamp for μCP of the present invention, at least the coating step, the bonding step, and the peeling step are used. In the present invention, any other steps other than these are used. Also good. The optional step used in the present invention is not particularly limited, and a step capable of imparting a desired function to the μCP stamp manufactured according to the present invention can be appropriately selected and used. Examples of such an optional process include a master plate decompression process after application of a PDMS film for reducing bubble contamination.

5). μCP Stamp The μCP stamp manufactured according to the present invention has a configuration in which a PDMS film having a concavo-convex shape formed on a surface is formed on a substrate. Such a stamp for μCP is used for micro contact printing (μCP). However, in the present invention, since it can be manufactured without a problem of air bubbles mixing, even a nano-order pattern can be obtained with high accuracy. It can be printed. Therefore, the μCP stamp manufactured according to the present invention can be used, for example, in a process of forming various electrodes of an organic semiconductor element using an organic transistor.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  The steps from master plate preparation to PDMS plate manufacture are shown below.

(Master plate making process)
Photoresist SU-8 (manufactured by Microchem) was spin-coated on a glass having a size of 300 mm × 400 mm and a thickness of 0.7 mm at a rotation speed of 1000 rpm and a holding time of 60 seconds. The film thickness at this time was about 3 μm. Thereafter, prebaking was performed at 65 ° C. for 30 seconds on a hot plate. Next, exposure (20 mJ / cm ² ) was performed with a quartz photomask (size 450 mm × 550 mm) having a minimum L & S of 5 μm. Next, the exposed substrate was dried at 65 ° C. for 30 seconds on a hot plate. Next, development was performed for 3 minutes with a dedicated developer (main component PGMEA solvent) to remove the resist in the unexposed portions. Finally, it was fully cured in a clean oven at 150 ° C. for 30 minutes. When the completed master plate was observed with an optical microscope, the plate depth was 3 μm, and an uneven pattern with a minimum L & S of 5 μm and a maximum L & S of 500 μm was formed. The master plate was spin-coated with a release agent (Durasurf, manufactured by Harves Co., Ltd.) at a rotation speed of 1000 rpm and a holding time of 30 seconds in order to improve the releasability of PDMS.

(Coating process)
PDMS (KE-106 manufactured by Shin-Etsu Chemical Co., Ltd.) in which 90 g of the main agent and 9 g of the curing agent were mixed with the master plate was uniformly applied to the entire surface with a dispenser (manufactured by Sanei Tech Co., Ltd.) so as to have a thickness of about 2 mm. After that, in order to remove bubbles in the pattern, it was put in a vacuum dryer and the pressure was reduced to 0.1 torr and held for 5 minutes.

(Adhesion process)
The bonding process of the master plate with PDMS and the supporting substrate (size 300 mm × 400 mm, thickness 0.7 mm) was performed using ST-50 (fine transfer device) manufactured by Toshiba Machine. The ST-50 manufactured by Toshiba Machine can control the contact speed between the upper head and the lower head to a minimum of 1 μm / s.

  The master plate with the PDMS film was vacuum-adsorbed on the lower head, and the upper head was vacuum-adsorbed on a glass substrate having a size of 300 mm × 400 mm and a thickness of 0.7 mm so that the contact angle was 30 ° or less. . Thereafter, the upper head was lowered at 500 μm / s until immediately before the upper substrate and the PDMS film contacted each other. Subsequently, the PDMS film and the upper substrate were brought into contact with each other at 1 μm / s in the low speed mode immediately before the contact. Further, the contact speed was maintained after contact at 1 μm / s, and it was pushed in until the gap between the upper head and the lower head was 1 mm, that is, the PDMS thickness was about 1 mm. Then, after pushing into a predetermined position at the same speed, it was left at room temperature for 16 hours to cure PDMS at room temperature.

(Peeling process)
The upper adsorption and the lower adsorption were released, the substrate and the master plate were taken out from the apparatus, and the substrate with the PDMS film was peeled from the master plate by hand to produce a μCP stamp. When the surface of the peeled PDMS film was observed with an optical microscope, an inverted pattern of the master plate was observed, and it was confirmed that an uneven pattern having a height of 3 μm, a minimum L & S of 5 μm, and a maximum L & S of 500 μm was formed. It was also confirmed that the PDMS film produced at a contact speed of 1 μm / s could be produced without any bubbles.

(Adhesion speed evaluation)
The manufacturing process other than contacting the master plate with the PDMS film and the upper substrate at 1 μm / s was performed in the same manner, and the contact speed was changed to three types of 5 μm / s, 10 μm / s, and 50 μm / s, A stamp for μCP was prepared and the degree of bubble contamination was evaluated.

As a result, there was no air bubble in the μCP stamp produced at 5 μm / s.
On the other hand, regarding the stamp for μCP produced at 10 μm / s, there was no bubble at the center of the substrate, but it was confirmed that many fine bubbles existed as it reached the substrate end face.
Furthermore, for the stamp for μCP produced at 50 μm / s, it was confirmed that there was a crater-shaped depression in the center of the substrate, and bubbles of various sizes were also present in the direction from the depression to the substrate end face. . Thus, by making the contact speed 5 μm / s or less, it was possible to produce a μCP stamp without bubbles.

It is the schematic which shows an example of the manufacturing method of the stamp for μCP of this invention. It is the schematic which shows an example of the manufacturing method of the stamp for μCP. It is the schematic explaining the problem of the bubble mixing in the manufacturing method of the stamp for μCP.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... PDMS film 2 ... Substrate 10 ... Micro contact printing (μCP) stamp 20 ... Master plate 100 ... Micro contact printing (μCP) stamp 101 ... PDMS film 102 ... Substrate 200 ... Master plate X ... Bubble

Claims (2)

Using a master plate having a fine concavo-convex pattern formed on the surface, applying a polydimethylsiloxane (PDMS) on the master plate, and using a substrate, the applied polydimethylsiloxane (PDMS) film A method for producing a stamp for microcontact printing (μCP), comprising: an adhesion step for bonding the substrate; and a peeling step for peeling the polydimethylsiloxane (PDMS) film and the substrate from the master plate,
A method for manufacturing a stamp for microcontact printing (μCP), wherein a contact speed for contacting the polydimethylsiloxane (PDMS) film and the substrate in the bonding step is 5 μm / s or less.   2. The method for manufacturing a stamp for micro contact printing ([mu] CP) according to claim 1, wherein the contact speed is in a range of 0.01 [mu] m / s to 1 [mu] m / s.

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