JP2013016633A - Wiring board manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board manufacturing method which solves a problem of the past such that though wiring is successfully thinned, it is necessary to arrange a liquid body containing a liquid repellent material having liquid repellency on a part where an ink including a conductive material as a functional fluid is not necessary to be formed and dry or harden the liquid body because there is a process of forming a liquid repellent part, and it is necessary to perform, when including drying and hardening of the ink containing the conductive material, drying and hardening twice other than hardening of a resin material of a slope part.SOLUTION: A wiring board manufacturing method in which a conductive pattern is formed on a base material by an inkjet method, comprises: a ground formation step of forming a ground layer of insulation containing unhardened hardening resin on the base material; a drawing step of forming a conductive pattern in the ground layer by injecting a pattern drawing ink containing conductive particles into the ground layer by an inkjet method; and a hardening step of hardening the ground layer.

Description

  The present invention relates to a method for manufacturing a wiring board in which a conductive pattern is formed by an inkjet method.

  A technique for forming a wiring by printing an ink containing a conductive material on a substrate by an inkjet method is known. In this technique, when ink containing a conductive material is ejected onto a base material, it spreads due to wettability with the base material. In particular, when the thickness of the wiring is necessary to reduce the wiring resistance, the wiring has to be thickened. In order to prevent this wetting and spreading, a technique for forming a liquid repellent portion is known. This is a pattern forming method for forming a pattern having a three-dimensional structure by applying a functional liquid containing a pattern forming material across a plurality of bent surfaces or curved surfaces as shown in FIG. Disposing a liquid material containing a liquid repellent material exhibiting liquid repellency with respect to the functional liquid 20 on a surface including a plurality of bent surfaces or a curved surface using an inkjet method, and forming the liquid repellent portion 16; And a step of disposing the functional liquid 20 in the lyophilic part where the liquid repellent part 16 is not formed.

The functional liquid 20 is ink containing a conductive material, and is a wiring material that connects the electrode of the semiconductor chip 123 and the electrode of the substrate 12. On the side surface of the semiconductor chip 123, a slope portion 127 made of a resin material is formed. The slope portion 127 forms a slope from the upper surface of the substrate 12 to the upper surface of the semiconductor chip 123, and the upper surface (surface 13 a) of the semiconductor chip 123 and the upper surface (surface 13 c) of the substrate 12 are formed in the slope portion 127. The functional liquid 20 is formed on the surface 13a, the surface 13b, and the surface 13c.

JP 2009-0776529 A

  In the conventional method of manufacturing a wiring board, since there is a step of forming the liquid repellent portion 16, the wiring can be thinned. However, the ink containing the conductive material as the functional liquid 20 is not desired to be formed. It is necessary to dispose a liquid material containing a liquid repellent material exhibiting liquid repellency, and to dry or harden it. Including drying or hardening of ink containing a conductive material, in addition to hardening of the resin material of the slope portion 127 , Drying or curing was required twice, and there was a problem of poor productivity.

The method for manufacturing a wiring board according to the present invention is a method for manufacturing a wiring board in which a conductive pattern is formed on a base material by an ink jet method, and a base formation for forming an insulating base layer containing an uncured curable resin on the base material And a step of forming a conductive pattern in the base layer by driving a pattern drawing ink containing conductive particles into the base layer by an inkjet method, and a curing step of curing the base layer. To do. As a result, pattern drawing ink containing conductive particles is injected into an insulating base layer containing an uncured curable resin, so that the spread of the pattern drawing ink can be suppressed and narrow wiring can be realized by one-time curing. it can.

In addition, the method for manufacturing a wiring board of the present invention includes a baking step of baking the pattern drawing ink after the curing step. As a result, the resistance of the wiring can be reduced.

In addition, the method for manufacturing a wiring board according to the present invention is characterized in that the pattern drawing ink does not dissolve in the base layer. As a result, the wiring can be made thinner.

In the method for manufacturing a wiring board according to the present invention, the base material has a step, and the base layer also serves as a planarizing layer for reducing the step. As a result, wiring can also be formed at the step.

  In the method for manufacturing a wiring board according to the present invention, pattern drawing ink containing conductive particles is driven into an insulating base layer containing an uncured curable resin, so that wetting and spreading of the pattern drawing ink can be suppressed and the width is narrow. Wiring can be realized with a single cure.

It is a figure explaining the manufacturing method of the wiring board of a 1st embodiment. It is a figure explaining the wiring board formed by the manufacturing method of the wiring board of 1st Embodiment. It is sectional drawing of the conductive pattern formed by the manufacturing method of the wiring board of 1st Embodiment. It is a figure explaining the manufacturing method of the wiring board of 2nd Embodiment. It is a figure explaining the manufacturing method of the conventional wiring board.

  Next, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram illustrating a method for manufacturing a wiring board according to a first embodiment of the present invention, and FIG. 2 is a diagram illustrating a wiring board formed by the method for manufacturing a wiring board according to the first embodiment. It is.

FIG. 1 is a diagram for explaining a method of manufacturing a wiring board according to the first embodiment. FIG. 1A shows a preparation process. The base material 2 is insulating glass or insulating resin.

Next, FIG.1 (b) shows a base | substrate formation process. As shown in FIG. 1B, an insulating base layer 7 containing an uncured curable resin is formed in a desired region on one side of the substrate 2. The material of the underlayer 7 is a UV curable acrylic resin having a thickness of about 10 to 40 μm. The underlayer 7 can be formed using an ink jet method or a dispenser.

Next, FIG.1 (c) shows a drawing process. As shown in FIG. 1C, a pattern drawing ink containing conductive particles is driven into the uncured underlayer 7 by an ink jet method to form a conductive pattern 6. By successively ejecting the pattern drawing ink droplets at an appropriate density, the pattern drawing ink droplets that have been deposited on the underlayer 7 are connected to each other, and the conductive pattern 6 is drawn. By being driven into the uncured underlayer 7, the pattern drawing ink can be formed so as to sink into the underlayer 7 as shown in FIG. By forming the conductive pattern 6 inside the base layer 7 in this way, the conductive pattern 6 can be prevented from being wet and spread by being blocked by the base layer 7, so that the width can be narrowed while maintaining the thickness of the wiring. It becomes possible. It is better to select a material so that the pattern drawing ink does not dissolve in the uncured underlayer 7. If the base layer 7 and the pattern drawing ink are made of a material that does not dissolve each other, the pattern drawing ink droplets are easily connected to each other, and the base layer 7 remains between the droplets and the conductivity of the conductive pattern 6 is not lowered. . The pattern drawing ink is exemplified by silver paste ink, but is not limited thereto, and may be a material containing conductive particles such as copper. The thickness of the conductive pattern 6 formed in the underlayer 7 is about 0.8 to 2.5 μm.

Next, FIG.1 (d) shows a hardening process. As shown in FIG. 1D, the underlayer 7 is cured. The underlayer 7 is cured until the uncured underlayer 7 is cured by UV irradiation using a metal halide lamp or the like.

The wiring board 1 as shown in FIG. 2 can be easily obtained by passing through the curing process of FIG. 1D from the preparation process of FIG. Since the pattern drawing ink containing the conductive particles is driven into the insulating base layer 7 containing the uncured curable resin, the spreading of the conductive pattern 6 can be suppressed, and a narrow wiring can be realized by one-time curing. As shown in FIG. 3A, the wiring width of the conductive pattern 6 directly formed on the substrate 2 is about 50 μm at the minimum, but the wiring width of the conductive pattern 6 on the base layer 7 is As shown in FIG. 3B, the line can be thinned to about 20 μm. In the present embodiment, the case where two conductive patterns 6 are routed in the vertical direction and two in the horizontal direction is illustrated, but the arrangement and number of the conductive patterns 6 are not limited thereto. .

Further, when forming the conductive pattern 6, it is preferable to form the conductive pattern 6 while scanning the ink jet head in the direction in which the conductive pattern 6 extends. As a result, the pattern drawing ink is ejected by shifting little by little, and the conductive pattern 6 can be formed without disconnection. For example, as shown in FIG. 2, when the conductive pattern 6 is routed in the vertical direction, in the drawing process of FIG. 1C, the inkjet head for driving the conductive pattern 6 is scanned in the vertical direction or the substrate 2 is moved in the vertical direction. When the conductive pattern is drawn in the horizontal direction, the inkjet head is scanned in the horizontal direction or the substrate 2 is scanned in the horizontal direction to perform drawing.

Further, a part of the conductive pattern 6 of the wiring board 1 may be formed on the base material 2 without the base layer 7 interposed therebetween. The terminal portion 9 shown in FIG. 2 is directly formed on the substrate 2 by a part of the conductive pattern 6. Since the base layer 7 is not provided, the pattern drawing ink spreads wet, but the terminal portion 9 that is electrically connected to an external device requires a certain area depending on the application and is not required to be so thin. In connection, it may be preferable that the base layer 7 is not provided. Thus, it may be devised to create a portion without the insulating base layer 7 containing the uncured curable resin in the portion where the thinning of the wiring is not desired.

Further, after the curing process shown in FIG. 1 (a) to the curing process shown in FIG. 1 (d), although not shown, a firing process may be performed. In the firing step, the pattern drawing ink 6 is fired after the curing step of the underlayer 7. When the pattern drawing ink 6 is a silver paste ink, baking is performed at a temperature of about 100 to 200 ° C. As a result, the resistance of the wiring can be reduced. Moreover, in this embodiment, although the case where the base layer 7 was UV curable acrylic resin was illustrated, the thermosetting resin which hardens | cures below the baking temperature of the pattern drawing ink contained in the conductive pattern 6 is used. It may be heat-cured. By selecting each material that does not dissolve the pattern drawing ink in the underlying layer 7, the wiring can be made finer.

[Second Embodiment]
FIG. 4 is a diagram for explaining a method of manufacturing a wiring board according to the second embodiment of the present invention. The same parts as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

FIG. 4 is a view for explaining a method of manufacturing a wiring board according to the second embodiment. FIG. 4A shows a preparation process. As shown in FIG. 4A, the present embodiment is different from the first embodiment in that a step 3 is provided on one side of the substrate 2. The step 3 is made of an insulating or conductive material having a thickness of about 1 to 100 μm.

Next, FIG.4 (b) shows a base | substrate formation process. As shown in FIG. 4B, an insulating base layer 7 containing an uncured curable resin is formed in a desired region on one side of the substrate 2 where the step 3 is provided. The underlayer 7 also serves as a planarizing film so as to reduce the step 3 of the base material 2, and further, a slope portion 5 is provided from the top of the step 3 toward the base material 2 without the step 3.

Next, similarly to the first embodiment, a drawing process shown in FIG. 4C and a curing process shown in FIG. 4D are performed.

By doing in this way, since the base layer 7 also serves as a planarizing layer for reducing the step 3, it is possible to form a thinned conductive pattern while maintaining the thickness without disconnecting the conductive pattern. . Moreover, in this embodiment, the level | step difference 3 of the preparation process of Fig.4 (a) may be wiring which consists of an electroconductive material. As a result, it is possible to easily form a wiring straddling a wiring already formed on the wiring board. Furthermore, when forming multilayer wiring, the curing process and the firing process in FIG. 4 (d) may be repeated from the base formation process in FIG. 4 (b).

DESCRIPTION OF SYMBOLS 1 Wiring board 2 Base material 3 Level | step difference 5 Slope part 6 Conductive pattern 7 Underlayer 9 Terminal part

Claims (4)

    In a method of manufacturing a wiring board in which a conductive pattern is formed on a base material by an ink jet method, a base forming step for forming an insulating base layer containing an uncured curable resin on the base material, and a pattern drawing ink containing conductive particles A method of manufacturing a wiring board, comprising: a drawing step of forming a conductive pattern in the underlayer by an ink jet method and a curing step of curing the underlayer. 2. The method for manufacturing a wiring board according to claim 1, further comprising a baking step of baking the pattern drawing ink after the curing step. 3. The method for manufacturing a wiring board according to claim 1, wherein the pattern drawing ink does not dissolve in the base layer. 4. The method of manufacturing a wiring board according to claim 1, wherein the base material has a step, and the underlayer also serves as a planarizing layer that reduces the step. 5. A method of manufacturing a wiring board characterized by the above.