JP2013247303A - Method and device for printing minute patterns in large area and functional electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of printing minute patterns that is inexpensive and suitable for mass production, especially applied to printing in a large area, a functional product having minute patterns further stable and highly reliable, and an electronic/electric device having minute circuit patterns.SOLUTION: A method of printing minute patterns includes at least the steps of: causing a print transfer plate formed of fine fiber forming mesh-like or substantially parallel-like patterns to hold coating material along the fine fiber; pressing the print transfer plate holding the coating material against a printing surface to transfer the mesh-like or substantially parallel-like patterns; and causing the pattern printed surface comprising the coating material to be subjected to fixing processing.

Description

  INDUSTRIAL APPLICABILITY The present invention is a method for selectively forming fine patterns directly on the surface of a substrate, and in particular, direct printing which is expected for functional electronic devices applied to mounting substrates and the like that have been actively researched recently. It belongs to the technical field. Providing new means and devices for the formation of functional patterns that are becoming increasingly finer and more sophisticated, and for the manufacture of electronic and electrical devices, printed electronics, bio-elements, etc. Achieves improvement and cost reduction, and is environmentally friendly, contributing greatly to resource and energy savings.

  There are many products in which complex patterns and metal wirings are formed on a substrate, and various forming methods and construction methods have been proposed and widely used. In particular, various wiring forming techniques have been developed for mounting boards for electronic and electrical devices with high added value and a large amount.

  There are widely used methods such as screen printing, gravure printing, ink-jet printing, etc., and obtaining a desired pattern or wiring by a method such as an exposure method after depositing, plating, or affixing a metal foil on the entire surface. In advanced mounting boards, traditional screen printing and gravure printing technologies are applied to some extent, but miniaturization is limited and the following high-cost exposure methods are mainly used. ing. For example, in the plating method, the substrate is first treated to lightly roughen the entire surface of the resin, and then a metal catalyst such as Pd is deposited on the rough surface, and then a metal such as copper is thinly plated by electroless plating. Further, thicken the metal by electroplating. Furthermore, it may be thickened by electroless plating. In addition, an extremely thin copper thin film is closely bonded to the resin substrate by a so-called adhesion method, a copper metal layer is formed by vacuuming by a vapor deposition method, and a metal film is formed on the entire surface of the resin substrate. The copper-clad resin substrate thus obtained is coated with a photosensitive resist, exposed, and the metal film is eroded and removed with an acid or the like to form a pattern. In these methods, as described above, the process is long, and many precise and expensive precision instruments are used, and there are many problems from the environmental aspect such as resource saving and energy saving.

  Recently, direct writing technology has attracted attention. For example, a technology for printing a nano silver paste and baking it to draw a conductive pattern: for example, a technology for directly drawing and forming a pattern with an ink jet printer has been widely researched and developed. However, many basic problems remain such as extremely low printing speed and very high cost. I haven't left the R & D stage yet. Hereinafter, the present invention will be described in detail using a leading mounting board as a representative example.

In the formation of a fine pattern on the surface of a resin substrate, as shown in the background art, after forming a metal layer on the entire surface, an opening formed by a photolithography process or the like is corroded to obtain a desired pattern. At this time, it is known that the bonding interface between the metal and the resin is eroded by the corrosive liquid and so-called underetching occurs. It is known that this interfacial erosion of sub to several microns not only causes a decrease in bonding strength and causes peeling, but also causes various defects. In addition, the eroded portion propagates and grows with use, so it has a negligible effect on long-term reliability.
Furthermore, when the width of the pattern becomes as fine as several tens of microns, this interfacial erosion of sub to several microns is not negligible, and it can be easily imagined that the effect is enormous.
In particular, the next-generation electric and electronic devices aim at a line width of 20 to 50 microns, and initial deterioration, aging deterioration, and characteristic change due to such interface erosion are major issues. Further, the size of the exposure machine is limited, and it can be said that it is almost impossible to produce a large fine pattern having a size of several tens of cm or more as shown in the present invention example.

  In any of the above-described methods, the total area required for the pattern portions and circuit patterns to be left is small, and it is a reality that most of the plated metal is removed. Furthermore, it is a major issue from the viewpoint of environmental costs associated with the treatment of waste liquids such as a large amount of corrosive liquid, and resource saving and energy saving. This issue is also one of the factors that have put emphasis on recent direct writing research and development.

  Unfortunately, it is difficult to draw a fine line in the ink jet method as a representative example, and the speed is very slow and it is not practical at all. The present situation is that the application to the element of a large area and an electronic device is not considered at all. Furthermore, the nanoimprint technology is suitable for printing very fine patterns, but is limited to printing in a very small area. It is still a basic research level that is artistic.

  The present invention relates to a fine conductive wire large-area printing method suitable for mass production, the same apparatus, and a functional electronic device.

  The gist of the process is to hold the paint along the fine fibers on a printing transfer plate made of fine fibers that form a net-like or almost parallel line pattern, and press the printing transfer plate holding the paint against the printing surface. In addition, it is characterized in that at least a step of transferring the mesh-like or substantially parallel line-like pattern and a step of fixing the pattern printing surface made of the paint are performed. Hereinafter, a detailed description will be given by following a well-known example of a mounting board that is widely used in electronic devices and the like.

  Based on FIG. 1, the gist of the present invention will be described. As shown in FIG. 1-A, a paint (such as a special paint containing a conductive metal or a substrate resin corrosive agent) 2 is soaked and held around a single fiber, composite fiber, or nano-shaped composite fiber 1 having a diameter D. . In addition, in the example of the composite fiber of the same figure, the cross-sectional state 3 which scraped off the excess coating material is shown.

  The printing transfer plate composed of the fine fibers 3 having the coating material is pressed against the printing substrate 4, and the coating material 2 is efficiently transferred by applying a stress by moving it slightly back and forth and right and left as necessary. This is subjected to fixing operations such as drying and heating to complete the pattern 2b. As a result, a desired conductive pattern almost determined by L = D + 2 to 6t and P = L + S depending on the configuration of the printing transfer plate 3 and application conditions is obtained. Therefore, a pattern of 10 microns or less can be printed with a fiber of 5 microns made of ultrafine nanofibers.

As is apparent from the above description, the concept is completely different from the screen printing mechanism in which the paint passes through the mesh according to the pattern formed on the mesh and forms the pattern on the printing surface. That is, in the present invention, a pattern is formed by transferring a paint entangled with the fibers. Therefore, in the present invention, it is effective to impart at least one specificity of the nanofiber composite fiber, the modified cross-sectional shape fiber, and the surface active fiber to the fine fiber forming the printing transfer plate so that the paint is easily spread and entangled. It is. The thickness of the transferred pattern increases by the increased amount of paint. Also, the conductive pattern can be thickened by electroplating.
Further, as shown in FIG. 2, the printing transfer plate 3 reinforces the transfer of the paint or the conductive paint by applying a stress by a fine movement in the vertical direction 5 and the front / rear / horizontal direction 6 relative to the printing surface 4. Also, it is very effective to provide a pressing portion for pressing the printing transfer plate 3 against the printing surface 4 to transfer the paint or the conductive paint.

  Further, using a special paint that corrodes the resin substrate 4 as the paint 2, the pattern was formed as described above, and then impregnated with a solution containing Pd, Ag, Zn, etc., and the catalytic metal was formed by corrosion. After depositing the pattern, a copper pattern is formed according to the pattern by electroless plating or the like. If necessary, the thickness can be further increased by electroplating or the like. As apparent from the above method, the metal pattern can be formed directly on the substrate without removing the metal by corrosion.

The shape of the transferred pattern, such as the width and height, mainly determines the amount of paint entangled with the fiber according to factors such as the surface tension, affinity, viscosity, and time of the paint. In general, the viscosity is desirably 10 to 10 ⁶ cp, desirably about 100 to 10 ⁵ cp, and the surface tension is preferably decreased by adding a surfactant or the like. Further, when the thickness t of the transfer printing portion is increased and the gap S between the patterns is clogged with fine printing, the mesh is likely to clog with the paint. At this time, it is important to prevent clogging of the pattern made of fine fibers forming the printing transfer plate and to remove excess paint. In order to prevent clogging, it is very effective to remove clogging with an air current, to remove excess paint with a scribing needle, a scraping jig or a roller.
In the case of using a corrosive paint, it is effective even if the viscosity is approximately one order of magnitude lower than the above-mentioned viscosity.

  Since the printing transfer plate is formed of continuous fine fibers, basically, a continuous fiber pattern can be formed as is apparent from the above description. At this time, as shown in FIG. 3, if the covering portion 23 is provided on the printing surface in advance and the covering portion is removed after the coating material is transferred thereon, a pattern according to the shape can be obtained. In addition to being able to divide a large printing transfer plate into several parts, various applications can be considered. In the figure, the covering portion is provided on the printing surface, but the same effect can be obtained even if the covering portion is provided in the corresponding portion of the printing transfer plate. For example, it is also effective to perform a surface treatment to repel the paint so that the paint does not get on.

An example of a forming apparatus based on the above-described fine pattern large area printing method is shown in FIG. First, the printing transfer plate 13 made of fine fibers comes into contact with the coating material supply unit 18 immersed in the coating material reservoir 17 to place the coating material, and if necessary, the excess coating material is removed through the excess coating material removal unit 19 to remove the excess coating material according to a predetermined pattern. Leave paint. At this time, even if the paint supply unit 18 and the excess paint removing unit 19 are integrated, the paint can be efficiently left in the same manner.
Next, the printing transfer plate 13 is moved and pressed onto the printing substrate 4 by the action of the drawer portion 20, and the back and forth motion 16 and the up and down motion 5 are further performed as necessary to promote the transfer. After the transfer, the printed substrate 4 is heated to fix the paint and complete the pattern. The printing transfer plate 13 can be folded back from the drawer 20 and returned to the paint supply unit 18 for continuous use. Moreover, the printing base 4 is made into a long sheet shape, and is pressed and brought into close contact with the printing transfer plate 13, thereby realizing efficient roll roll printing. At this time, it is effective to apply ultrasonic vibration to the transfer surface as the above-mentioned transfer promotion.
The functional electronic device created with the completed pattern in this way does not use an acid or other corrosive agent during pattern formation, has no defects due to underetching or acid residue, etc., and has high reliability. high. Moreover, as described above, it is a functional electronic device that is environmentally friendly and saves resources and energy.

  The present invention is a low-cost fine pattern printing method suitable for mass production of fine patterns, particularly for a large area that has not been heretofore, and a functional product or a fine circuit having a fine pattern that is stable and highly reliable. An electro-electrical device having a pattern can be provided. In a fine circuit pattern used for an electronic / electrical device, a decrease in peel strength and a decrease in reliability are caused by an undercut or interface deterioration caused by the formation of fine lines. Such harmful effects are resolved.

  In addition, the conventional process goes through many treatment processes including a corrosion process, which increases the maintenance and adjustment costs of various facilities and various equipment, and also has the drawbacks of soiling and scratching the surface each time the treatment process is performed. Although there was a decrease in reliability, in the present invention, the entire process was greatly simplified to form a pattern directly, and these problems were solved at once. Furthermore, not only the process was simple and the operation rate was improved, but also secondary effects such as a significant improvement in productivity such as an increase in yield were recognized.

  Furthermore, in the present invention, the resources are saved because the pattern is directly formed, and an extra corrosive solution for removing the metal plated on the entire surface is not necessary. The cost reduction effect by these is great, and it is also environmentally friendly.

Principle diagram Convex transfer concept Covering formation concept Example of basic layout of forming equipment

The basic fine conductive pattern printing method of the present invention will be described in detail below in accordance with a leading mounting board as a typical application example. Needless to say, a variety of applications can be developed by combining the substrate, the paint, and various members.
Basically, using a very simple example of the present invention, a parallel silver wire having a width of 30 microns is formed over an entire surface of a glass sheet having a thickness of 50 to 1 mm and 1 m × 2 m as an insulating substrate at intervals of 500 microns. The essential points of the present invention will be described.

  First, the surface was degreased and cleaned (cleaning by general plasma treatment or ozone treatment), and placed on a substrate having a gentle convex surface as shown in FIG. Next, a printing transfer plate in which countless fine fibers having a diameter of 20 microns are stretched at intervals of 500 microns is attached to a printing forming apparatus as shown in FIG. 4, and after applying a conductive silver paint, it is pressed against the printing surface. The conductive silver paint was transferred by performing a fine movement of about 5 microns from front to back and from side to side. Thereafter, in order to fix the paint, it was heated at 250 degrees to complete the formation of the conductive pattern, and a desired finished product was obtained.

In addition, the line width changed with the density | concentration and viscosity of a coating material, and when the density | concentration and viscosity were high, the tendency to become thick was recognized. At this time, the thickness of the line width could be kept constant by reducing the fine movement.
Also, in order to form a break, as shown in FIG. 3, a tape is affixed on the substrate to form a coating portion, and after the transfer printing as described above, the coating is removed and heat treatment is performed to obtain a finished product. It was. As a result, parallel line patterns of parallel silver lines could be separated and divided.
Some typical examples are shown below.

  Aiming at forming parallel silver wires with a width of 30 microns at intervals of 500 microns on a glass sheet having a thickness of about 0.4mm and a length of 1m x 2m as an insulating substrate, the surface is first degreased. Then, it was cleaned by general plasma treatment or ozone treatment and placed on a substrate for printing. Next, a printing transfer plate in which countless fine fibers having a diameter of 20 microns are stretched every 500 microns is stretched on a printing forming apparatus as shown in FIG. Was transcribed. Thereafter, the conductive pattern was fixed by heating at 250 degrees to obtain a finished product. At this time, in the case of printing transfer, condition 1: flat substrate, condition 2: when using a substrate having a gentle convex surface whose central part is higher than the end part by about 1 cm as shown in FIG. 2, condition 3 / condition 4: each Table 1 shows the results obtained by examining the case where a fine movement of about 5 microns in the longitudinal direction is used in combination with Condition 1 / Condition 2 in the longitudinal direction.

  It was observed that the amount of paint transferred increased due to the effect of the convex surface and fine movement. It was estimated that the film became slightly thicker due to vibrations during the movement and play of the equipment under the fine movement in which the paint was stressed. Note that even in Condition 1, a small area of 10 cm level was satisfactory.

In Example 1, transfer printing was attempted on a substrate having a printed surface with a step of about 2 microns.
Table 2 shows the results corresponding to Conditions 1 to 4 in Conditions 5 to 8, respectively.
A large effect of convex surface and fine movement was observed.

Example 1 In condition 1, conductive patterns were formed by changing the fine fibers as follows.
Condition 9: The surface of the fine fiber is plasma-irradiated to improve the placement of the paint. Condition 10: The results of using the nanocomposite fiber having the nanostructure as shown in the left figure of FIG. 1A are shown in Table 3. In all cases, improvement was observed, and it was proved that there was a good effect even under bad conditions.

  In Example 4 Condition 4, a conductive pattern was formed using a printing transfer plate in which fine fibers having a diameter of 20 microns were partially stretched every 200 microns. Table 4 shows the results of adjusting the viscosity of the paint with a diluent or thickener and examining the changes and effects.

  In Example 4, an attempt was made to form a conductive pattern using the surplus paint removing portion shown in FIG. The results of examining the effect are shown in Table 5. As shown in the left figure of FIG. 1A, it was estimated that the excessive coating material was removed and the clogging of the printing plate was prevented. Improvement was seen in all conditions.

  In Example 5, an attempt was made to remove excess paint or eliminate clogging by blowing an air current to the surplus paint removing unit shown in FIG. 4 or installing a scribing needle. The results of examining the effect are shown in Table 6. Under any condition, the level was improved to almost the same level as in Example 5.

Example 2 In conditions 1 and 4, printing transfer was carried out with a 500 μm square mesh printing transfer plate woven with countless 20 micron diameter fine fibers instead of parallel stretched fine fibers. Since tension is acting in the longitudinal direction but weak in the lateral direction, a plate having high strength in the lateral direction was prepared by arranging high tension fibers at both ends of the plate.
As a result, it is presumed that a mesh pattern in which the tension is transmitted in the longitudinal and transverse directions of the entire printing plate is formed. In order to take advantage of this feature, a vibration of 5 microns was given in the lateral direction in addition to the longitudinal direction. The results are shown in Table 7. The line width is thick because there is also effective movement in the horizontal direction.

According to condition 4 of Example 1, a corrosive paint 2 containing 5N caustic potash was used, and a polyimide film was applied as the substrate 4. As a result, a corroded portion was formed along the pattern. Furthermore, electroless plating was performed by applying a commonly used electroless copper deposition method to obtain a copper deposit as patterned. That is, the corroded polyimide film was immersed in a liquid containing Pd chloride, washed with water, and then reduced to deposit nano Pd particles, and electroless copper was deposited using this as a nucleus. The average line width was 22 microns.
Furthermore, a 3 micron thick copper film was additionally formed by electroplating. As a result, the line width was thick and was approximately 28 microns.
(Comparative Example 1)

Conventional screen printing was performed in the same manner as in Example 1. A printing plate was possible, but printing failed. As a result of trial using a printing plate of 70 microns instead of 30 microns, predetermined good printing was achieved.
In the trial using the ink jet method, a line width of about 50 microns could be somehow realized, but the formation speed was extremely slow, and it took time even for a small 10 cm square, and large printing as in the example was impossible. . The gravure printing method is good at large and long printing, but the line width is practically 100 microns. Printing below 50 microns is considered difficult for the time being.
Table 8 summarizes the characteristics of each method.

以上の説明で明らかなように、本発明の微細紋様大面積印刷法によれば、微細紋様の大型の印刷が廉価で形成される環境に優しく省資源の転写印刷工法である。さらに同方法に基づく微細紋様大面積印刷装置により形成された機能性電子装置は、品質や信頼性が高く、更に低コストである。更に、省資源省エネにも大きく寄与する機能性電子装置である。

As is apparent from the above description, according to the fine pattern large area printing method of the present invention, it is an environment-friendly and resource-saving transfer printing method in which large prints of fine patterns are formed at low cost. Furthermore, the functional electronic device formed by the fine pattern large-area printing apparatus based on the same method has high quality and reliability, and is low in cost. Furthermore, it is a functional electronic device that greatly contributes to resource saving and energy saving.

  In addition, as is clear from the above description, not only can a large area and high-speed transfer printing be possible, but also there is a feature that endless transfer / printing can be achieved by using a long film.

The present invention belongs to the field of microcontact printing technology, a method for directly forming a selective functional pattern on the surface of a substrate, which has been actively researched recently. Transfer printing is possible at a low price.
In particular, the present invention is applied to large-sized electronic and electrical devices that are very difficult to produce by other methods. It has become increasingly refined and sophisticated, providing new means for the formation of large-scale functional patterns and the manufacture of electronic and electrical devices, and at the same time, greatly improves its quality and reliability, while further saving resources and energy. Realize cost reduction.

1 Fine fiber with paint (example of single fiber, nano-shaped fiber)
2a Paint on fiber 2b Paint transferred to printing surface 3 Fine fiber part of printing transfer plate with paint
4 printing substrate 5 fine vertical movement, pressing 6 left and right, forward / backward movement 13 printing transfer plate made of fine fiber with paint
16 Back and forth movement 17 Paint reservoir
18 paint supply part 19 surplus paint removal part 20 drawer part 23 example of covering part for forming cut

Claims (10)

A step of holding a paint along the fine fibers on a printing transfer plate made of fine fibers forming a mesh-like or substantially parallel line pattern, pressing the printing transfer plate holding the paint against the printing surface, and A method of forming a fine pattern comprising at least a step of transferring a pattern of substantially parallel lines or a pattern of parallel lines, and a step of fixing the pattern printing surface formed from the paint 2. The method for forming a fine conductive pattern according to claim 1, wherein the paint is composed of a conductive paint or a corrosive paint. A step of holding a paint along the fine fibers on a printing transfer plate made of fine fibers forming a mesh-like or substantially parallel line pattern, pressing the printing transfer plate holding the paint against the printing surface, and Forming device of fine conductive pattern, including at least a step of transferring a pattern of substantially linear lines or substantially parallel lines, and having a function of transferring the paint 4. A fine pattern print forming apparatus comprising at least the process according to claim 3 and further comprising a clogging prevention and surplus paint removing unit composed of fine fibers forming the printing transfer plate. 5. The method according to claim 3, comprising at least the step according to claim 4, wherein the printing transfer plate is applied with at least one fine perturbation or stress relative to the printing surface in the vertical, front, back, left and right directions to transfer the paint or the conductive paint. Fine pattern print forming device with function 5. A fine pattern print forming apparatus comprising at least a step according to claim 3 and 4, further comprising a pressing portion for pressing the print transfer plate against a printing surface, and having a function of transferring the paint or the conductive paint. 5. A fine pattern comprising at least one of a nanofiber composite fiber, a modified cross-sectional shape fiber, and a surface active fiber, comprising at least the step according to claim 3 and 4 and forming the printing transfer plate Printing forming equipment A process of holding a conductive paint along a fine pattern on a printing transfer plate made of fine fibers that form a mesh-like or almost parallel line pattern, and pressing the printing transfer plate holding the conductive paint against the printing surface And having a fine conductive pattern, which is created through at least a process of transferring the mesh pattern or a pattern of substantially parallel lines, and a process of fixing the pattern print surface made of the conductive paint. Electronic equipment The method for forming a fine conductive pattern according to claim 1, wherein when the coating or the conductive coating is transferred to the printing surface of the printing transfer plate, a continuous conductive pattern is appropriately formed with a covering portion that is interrupted. , Print forming apparatus thereof, and functional electronic apparatus having fine conductive pattern A printing transfer plate for use in a fine pattern print forming apparatus, characterized in that the fine fibers have at least one specificity of nanofiber composite fibers, irregular cross-sectional shape fibers, and surface active fibers

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