JP2017037975A - Manufacturing method of printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a printed circuit board capable of providing a pattern electrode at lower cost and more easily and capable of easily manufacturing even a printed circuit board of a relatively large area.SOLUTION: The manufacturing method of a printed circuit board includes: providing a mask 12 on a metal film 10b, formed on a substrate; and chemically etching an exposed part thereof to provide a pattern electrode. The mask 12 is provided by disposing a wire mesh on the metal film, providing a mask solution, and interposing it between the metal film 10b and the mesh to harden the mask solution.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a printed circuit board, and more particularly to a method for manufacturing a printed circuit board having a pattern electrode.

  There is a printed circuit board on which electronic components are fixed and wiring is provided between them. For example, a laminated substrate in which a metal film made of Cu (copper) foil is provided on an insulating substrate made of a phenol resin or an epoxy resin is prepared, and the metal film is scraped off in a predetermined pattern to give a wiring pattern. For etching the metal film, a chemical etching method can be used in combination with a photolithography method using a photosensitive resin capable of obtaining a highly accurate pattern. In particular, when Cu is used for the metal film, it is more likely to be oxidized than Ag (silver) or the like, and such a photolithography method is often employed.

  By the way, a printed circuit board in which pattern electrodes are arranged in a mesh shape is used as a printed circuit board for an input device such as a switch of an infrared remote controller or a keyboard of a personal computer. In recent years, transparent electrode printed boards that combine transparent electrodes with pattern electrodes as image display panels such as liquid crystal panels and organic electroluminescence panels, solar battery panels, and various input devices such as mobile phones and tablet terminals are also available. Widely used. Many of the patterned electrodes of such printed circuit boards are also manufactured by photolithography.

  For example, Patent Document 1 discloses a transparent electrode substrate formed by laminating a transparent conductive layer in which a conductive metal mesh layer is embedded on one surface of a transparent substrate. Such a conductive metal mesh layer is formed by forming a first transparent conductive layer on one surface of a transparent substrate, forming a conductive metal layer in a film shape on the first transparent conductive layer, and patterning it by a photolithography method. It is supposed to be obtained. A second transparent conductive layer is formed on the conductive metal layer to constitute a transparent electrode substrate. Typically, the mesh opening pitch is 0.1 to 10 mm, and the line width is 10 nm to 1000 μm.

  In general, the photolithography method is a relatively expensive process because it involves many steps such as resist application, pattern exposure, cleaning to remove an unnecessary mask (resist), etching, and mask peeling. Moreover, it is difficult to give a wiring pattern to a larger area like a printed circuit board on which pattern electrodes are arranged. Further, depending on the transparent substrate, it may be difficult to perform etching thereon.

  Thus, for example, Patent Document 2 discloses an electrode sheet for a capacitive touch panel in which a part of a thin wire-like conductive linear member is embedded in a transparent adhesive layer having insulation and arranged in a mesh shape. . The transparent adhesive layer is attached to the front surface of a display, etc., and when the pressure of the operator's hand, pen, etc. is applied from this pattern part, the information on the screen position is sensed and an information signal is output to the outside. It is supposed to. It is stated that the conductive linear member forming the mesh-shaped pattern electrode is thin to give light transmission, has a width of 1 to 50 μm, and a line interval of 50 to 2000 μm.

JP 2012-142500 A JP 2012-123570 A

  In the method of manufacturing a printed circuit board by a photolithography method in which a mask is provided on a metal film formed on a substrate and the exposed portion is chemically etched to provide a pattern electrode, the above-described mask coating and pattern exposure are performed. It is desirable to simply provide the steps of cleaning, and final mask removal. In particular, there is a high demand for a method of manufacturing a printed circuit board having a pattern electrode that becomes a repeated pattern.

  The present invention has been made in view of the situation as described above, and its object is a method for manufacturing a printed circuit board that can provide a pattern electrode at a lower cost and with a relatively large area. The present invention provides a method that can be easily manufactured even for a printed circuit board.

  A method for manufacturing a printed circuit board according to the present invention is a method for manufacturing a printed circuit board in which a mask is provided on a metal film formed on a substrate and the exposed portion is chemically etched to provide a patterned electrode. A wire mesh made of a wire having a round cross section is disposed on the film, a mask solution is provided and interposed between the metal film and the mesh, and the mask solution is cured to provide a mask.

  According to this invention, the mask solution is automatically arranged on the substrate along the wire mesh by capillary action and is easily peeled off simply by arranging the wire mesh composed of the wire having a round cross section on the substrate. Therefore, the mask can be formed on the substrate more inexpensively and easily. As a result, a printed board having a pattern electrode can be manufactured more inexpensively and easily. Moreover, even a printed circuit board having a relatively large area can be easily manufactured.

  In the above-described invention, the mask solution may be a PVA aqueous solution. Furthermore, the PVA aqueous solution may further contain an acrylic resin. According to this invention, a mask for chemical etching of the metal film can be ensured, and removal of the final mask after etching can be simplified. As a result, a printed board having a pattern electrode can be manufactured more inexpensively and easily.

  In the above-described invention, the wire mesh may be made of a wire knitted in a lattice shape. By waving the wire on the substrate, the arrangement of the mask solution along the wire mesh can be more reliably and easily performed. As a result, a printed substrate having a pattern electrode can be manufactured more inexpensively and easily. Moreover, even a printed circuit board having a relatively large area can be easily manufactured.

  In the above-described invention, the metal film may be made of Cu. Even Cu that is relatively easy to oxidize does not deteriorate this, and as a result, a printed circuit board having a pattern electrode can be manufactured more inexpensively and easily.

It is a flowchart of the manufacturing method of the printed circuit board by this invention. It is a perspective view of a blank substrate. It is sectional drawing in 1 process of the manufacturing method of the printed circuit board by this invention. It is a top view of a mesh. It is a top view which shows the proximity | contact point of a mesh. It is a top view of the board | substrate in the manufacturing method of the printed circuit board by this invention. It is the photograph in 1 process of the manufacturing method of the printed circuit board by this invention. It is sectional drawing in 1 process of the manufacturing method of the printed circuit board by this invention.

  A method of manufacturing a printed circuit board as one embodiment of the present invention will be described along FIG. 1 with reference to FIGS. 2 to 8 as appropriate.

  As shown in FIG. 2, a blank substrate 10 is prepared in which a metal film 10b for providing a pattern electrode is laminated on a base material 10a (FIG. 1, S1).

  The base material 10a is not particularly limited in material, but is preferably made of an epoxy resin or a phenol resin and chemically stable with respect to an etching solution described later. The metal film 10b is made of a conductive metal, and is generally preferably made of Cu or a Cu alloy.

  As shown in FIG. 3, the blank substrate 10 is horizontally arranged with the metal film 10b on top, and the mesh 20 is arranged thereon (FIG. 1, S2).

  As shown in FIG. 4, the mesh 20 is preferably a wire mesh in which warp yarns 20a and weft yarns 20b made of a wire having a round cross section are alternately stacked one above the other and flat knitted in a lattice shape. By alternately superposing the warp yarn 20a and the weft yarn 20b vertically, the respective yarns are combined in a wave shape. When the mesh 20 is arranged on the blank substrate 10, as shown in FIG. 3, the weft 20b has a proximity point A that is close to the blank substrate 10 at regular intervals. Similarly, the warp 20a is also along this. Proximity points A are provided at predetermined intervals. That is, as shown in FIG. 5, the proximity points A are dispersed in the form of dots on the surface of the substrate 10. This will be further described later.

  Next, a mask solution 12 that gives a mask 12 '(see FIG. 5) for etching the metal film 10b is dropped onto the blank substrate 10 from above the mesh 20 (FIG. 1, S3). At this time, the mask solution 12 spreads on the blank substrate 10 by a capillary phenomenon, and is adjacent to the adjacent point A along the mesh 20 so as to be connected between the metal film 10b. This will be described later.

  The mask solution 12 is a liquid that spreads on the blank substrate 10 along the mesh 20, and cures to function as a mask 12 '. Here, it is a 1 wt% aqueous solution of polyvinyl alcohol (PVA), and preferably further contains an acrylic resin.

  Next, as shown in FIG. 6A, the mask solution 12 is sufficiently dried and cured at room temperature to form a mask 12 'on the metal film 10b (FIG. 1, S4). Then, the mesh 20 is removed from the mask 12 '(S5 in FIG. 1).

  Here, if the mesh 20 is a wire mesh as described above, the warp yarn 20a and the weft yarn 20b are combined in a wavy shape, so that the mesh 20 can be easily detached from the mask 12 '. FIG. 7 shows a state in which a mask 12 ′ is provided on the substrate 10 using a mesh 20 having a lattice shape with a side of 52 μm by a wire having a diameter (line width) of 4.7 μm. The metal film 10b is exposed between the masks 12 '.

  Next, the exposed portion of the metal film 10b exposed from the mask 12 'is chemically etched with an etchant (FIG. 1, S6).

  If the etching solution is a metal film 10b made of Cu or a Cu alloy, an iron chloride 1 wt% methanol solution or the like can be used. Further, the etching solution can etch away the metal film 10b without greatly affecting the cured state of the mask 12 '. As the etching solution, known ones such as sodium persulfate and potassium persulfate can be used, but it is preferable to contain water as little as possible in combination with PVA.

  As shown in FIG. 6B, when the mask 12 ′ is removed with a predetermined solvent and the substrate 10 is further washed, the substrate 10 having the pattern electrode in which the mesh 20 is transferred onto the base material 10a is obtained (FIG. 6B). 1, S7).

  By the way, in step S3 in which the mask solution 12 is dropped, as shown in FIG. 5, the wires 20 (20a and 20b) of the mesh 20 are arranged on the blank substrate 10 in a wave shape, and the proximity point A is constant. Arranged in a grid at intervals. The mask solution 12 flows from one proximity point A to the adjacent proximity point A by capillary action, and as a result, the mask solution 12 is arranged along the mesh 20.

  Further, as shown in FIG. 8, the mask solution 12 is removed from the substrate 10 in an attempt to spread along the wires 20 a (20 b) of the mesh 20 due to surface tension. As a result, the mask solution 12 is applied to the mesh 20. The mask 12 ′, which is disposed along and cured, forms a relatively high wall surface on the substrate 10.

  According to the embodiment described above, a mask 12 'is provided on the metal film 10b formed on the substrate 10, and the exposed portion is chemically etched to provide a pattern electrode. In a manufacturing method, a process can be given simply. In particular, a pattern electrode having a repetitive pattern such as a grid electrode can be provided very easily and inexpensively even if it has a large area. Moreover, even if it is Cu which is comparatively easy to oxidize, a pattern electrode can be given without deteriorating this.

  So far, representative examples and modified examples based on the examples have been described, but the present invention is not necessarily limited thereto. Those skilled in the art will recognize a variety of alternative embodiments without departing from the scope of the appended claims.

DESCRIPTION OF SYMBOLS 10 Substrate 10a Base material 10b Metal film 12 Mask solution 12 'Mask 20 Mesh

Claims (5)

A method of manufacturing a printed circuit board that provides a pattern electrode by applying a mask on a metal film formed on a substrate and chemically etching the exposed portion,
A wire mesh composed of a wire having a round cross section is disposed on the metal film, a mask solution is provided and interposed between the metal film and the mesh, and the mask solution is cured to provide a mask. A printed circuit board manufacturing method.   The method for manufacturing a printed circuit board according to claim 1, wherein the mask solution is a PVA aqueous solution.   The printed circuit board manufacturing method according to claim 2, wherein the PVA aqueous solution further contains an acrylic resin.   4. The method of manufacturing a printed circuit board according to claim 1, wherein the wire mesh is made of a wire knitted in a lattice shape. The method of manufacturing a printed circuit board according to claim 1, wherein the metal film is made of Cu.

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