JP2011108704A - Printed wiring board and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a printed wiring board including large current wiring and signal wiring by simple manufacturing steps. <P>SOLUTION: The method of manufacture a printed wiring board includes a step for etching a part of a conductor layer covering at least one surface of an insulating substrate 11 to form a pattern from which the conductor layer is removed, a step for forming a groove pattern 33 by removing the part of the insulating substrate 11 in the pattern from which the conductor layer is removed, a step for forming large current wiring 21 by inserting a conductor pattern having a shape suitable to the groove pattern 33 into the groove pattern 33, a step for fixing the large current wiring 21 and the groove pattern 33 with adhesive 22, and a step for forming signal wiring 13 by patterning the residual part of the conductor layer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a printed wiring board and a manufacturing method thereof, and more particularly to a printed wiring board including a signal circuit and a large current circuit and a manufacturing method thereof.

  In a printed wiring board, a signal circuit (wiring) and a large current circuit (wiring) are mixed. When the film thickness of the conductor layer constituting the wiring pattern is increased, it becomes difficult to etch the fine wiring, so that it is difficult to arrange the signal wiring and the large current wiring in the same layer. For this reason, several methods for manufacturing a printed wiring board in which the high-current wiring and the signal wiring are formed in different layers have been proposed. Patent Document 1 and Patent Document 2 describe a method of manufacturing a printed wiring board in which a punching groove is formed in an insulating substrate and a conductor pattern that becomes a high-current wiring is embedded in the groove. In these documents, a prepreg sheet is attached to the upper surface or the lower surface of an insulating substrate embedded with a large current wiring by heating and pressing, and the large current wiring is fixed in a groove of the insulating substrate. Thereafter, general signal wirings are formed on both surfaces of the insulating substrate and the prepreg sheet.

Japanese Patent No. 3509315 (FIG. 1) Japanese Patent Laid-Open No. 07-235756 (FIG. 3)

  In the techniques described in Patent Document 1 and Patent Document 2, in order to fix the conductor layer in the punching groove of the insulating substrate, a prepreg sheet is laminated on the insulating substrate. The process of laminating the prepreg layer complicates the printed wiring board manufacturing process.

  In view of the problems in the related art, the present invention provides a printed wiring board including a large current wiring and a signal wiring, which can be manufactured without requiring lamination of an insulating substrate and a prepreg sheet, and a manufacturing method thereof. The purpose is to do.

  In order to achieve the above object, the present invention provides a step of etching a part of a conductor layer covering at least one surface of an insulating substrate to form a conductor layer removal pattern, and the conductor layer of the insulating substrate. Removing a portion in the removal pattern to form a groove pattern, inserting a conductor pattern having a shape suitable for the groove pattern into the groove pattern, and at least between the conductor pattern and the groove pattern There is provided a method for manufacturing a printed wiring board, comprising: a step of fixing with an adhesive; and a step of patterning a remaining portion of the conductor layer to form a wiring pattern.

  The present invention also provides an insulating substrate having a groove pattern formed on at least one surface, a conductor pattern inserted into the groove pattern and fixed by an adhesive, and the other than the groove pattern. Provided is a printed wiring board comprising a wiring pattern formed on a surface of an insulating base material.

  The printed wiring board of the present invention and the printed wiring board manufactured by the method of the present invention are manufactured without the need for laminating a prepreg or the like on an insulating base material because the conductor pattern and the groove pattern are fixed with an adhesive. The process is simplified.

FIGS. 1A to 1E are a plan view and a cross-sectional view showing a printed wiring board according to the first embodiment of the present invention. FIGS. 2A and 2B are a front view and a back view of an insulating substrate, respectively showing one step of the manufacturing process of the printed wiring board of FIG. FIGS. 3A to 3C are a front view, a back view, and a cross-sectional view of an insulating substrate, showing process steps subsequent to FIG. (A)-(c) is the top view and sectional drawing of the conductor pattern accommodated in the groove | channel of the insulated substrate of FIG. FIGS. 4A to 4C are a front view, a back view, and a cross-sectional view of a printed wiring board, showing process steps subsequent to FIG. FIG. 6 is a cross-sectional view of a printed wiring board showing a process step subsequent to FIG. Sectional drawing of the printed wiring board which concerns on the 2nd Embodiment of this invention.

  Prior to the description of the embodiments of the present invention, an outline of the present invention will be described. The method for producing a printed wiring board of the present invention includes a step of etching a part of a conductor layer covering at least one surface of an insulating base material to form a conductor layer removal pattern, and the conductor layer removal of the insulating base material. Removing a portion in the pattern to form a groove pattern, inserting a conductor pattern having a shape suitable for the groove pattern into the groove pattern, and bonding at least between the conductor pattern and the groove pattern A step of fixing with an agent, and a step of patterning the remaining portion of the conductor layer to form a wiring pattern.

  The printed wiring board of the present invention includes an insulating base material having a groove pattern formed on at least one surface, a conductor pattern inserted into the groove pattern and fixed with the groove pattern and an adhesive, and other than the groove pattern. And a wiring pattern formed on the surface of the insulating substrate.

  The printed wiring board of the present invention and the printed wiring board manufactured by the method of the present invention are manufactured without the need for laminating a prepreg or the like on an insulating base material because the conductor pattern and the groove pattern are fixed with an adhesive. The process is simplified.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1A and 1B show a printed wiring board according to a first embodiment of the present invention. FIGS. 1A to 1E are a front view and a back view, respectively, and a cross-sectional view taken along line AA in FIG. It is -B sectional drawing and CC sectional drawing. The printed wiring board shown in FIG. 1 can be used as a printed wiring board by itself, but may be laminated with another printed wiring layer including a wiring pattern and an insulating layer. In the present embodiment, the structure shown in FIG. 1 is called a printed wiring board, and a structure laminated with another printed wiring layer is also called a printed wiring board.

  A printed wiring board 10 in FIG. 1 includes an insulating substrate (hereinafter referred to as an insulating base material) 11, a high-current wiring 21 formed on the front and back surfaces of the insulating base material 11, and the front and back surfaces of the insulating base material 11. It has a surface layer pattern constituting the formed signal wiring 13 and wiring lands (hereinafter referred to as lands) 12 formed on the front and back surfaces of the insulating base material 11. In this example, the printed wiring board 10 includes one insulating base material 11 and two wiring layers. The large current wiring 21 forms, for example, a power wiring or a ground wiring, and supplies power to the signal circuit including the signal wiring 13 and the land 12. The printed wiring board 10 includes power wiring and ground wiring (not shown) having similar shapes as other large current wiring. In the following description, the large current wiring 21 is described as a power supply wiring.

  The power supply wiring 21 formed on the surface of the insulating base material 11 is formed on the back surface of the insulating base material 11 and connected to the power supply wiring 21 and the land 12 through a conductor plug (not shown) filled in the through hole 14. . The power supply wiring 21 formed on the back surface of the insulating base material 11 is connected to the power supply wiring 21 and the land 12 formed on the front surface of the insulating base material 11. The power supply wiring 21 is configured by a conductor pattern having a large thickness inserted into a groove 33 formed in the insulating base material 11. The signal wiring 13 and the land 12 are formed from a patterned copper foil formed on the front surface and the back surface of the insulating base material 11.

  As shown in the cross-sectional views of FIGS. 1C to 1E, the power supply wiring 21 has a forward taper shape in which the width is large near the bottom of the groove 33 and the width decreases toward the surface of the groove 33. A gap between the side wall of the groove 33 and the power supply wiring 21 is filled with an adhesive 22, and the power supply wiring 21 is fixed inside the groove 33 by the adhesive 22. The surface of the power supply wiring 21 slightly protrudes from the surface of the insulating base 11 and is in the same plane as the surfaces of the signal wiring 13 and the land 12 made of copper foil. Although the signal wiring 13 is shown only on the front surface of the insulating base material 11, it is formed on the back surface of the insulating base material 11 in the same manner.

  Hereinafter, a method for manufacturing the printed wiring board of FIG. 1 will be described with reference to FIGS. In FIG. 2, for example, a copper foil 31 is formed on the front and back surfaces of an insulating base material 11 made of an epoxy resin having a thickness of about 5 mm by a known method, for example, an electroless plating method. The copper foil 31 on the front surface and the back surface is etched to remove a portion that matches the conductor pattern of the power supply wiring 21 to be formed later, and a copper foil removal portion 32 is formed on the copper foil 31. FIG. 2 shows the wiring board at this step. Next, the insulating base material 11 of the copper foil removed portion 32 is etched to a predetermined depth to form a groove (groove pattern) 33 (FIG. 3). The depth of the groove 33 is a dimension smaller than ½ of the thickness of the insulating base material 11, for example, 2 mm.

  Next, a conductor pattern to be the power supply wiring 21 prepared in advance is embedded in the grooves 33 on the front surface and the back surface. The shape of the conductor pattern 21A is shown in FIG. FIG. 6A shows the conductor pattern 21A embedded in the groove 33 formed on the surface of the insulating base material 11, and FIG. 5B shows the conductor pattern 21A embedded in the groove 33 formed on the back surface of the insulating base material 11. The conductor patterns 21A are shown respectively. FIG. 2C is a DD cross-sectional view of the conductor pattern 21A on the back surface. The conductor pattern 21A is formed by etching a copper plate. The width (a1) of the groove bottom of the conductor pattern 21A is 20 mm, for example, and the width (a2) of the top surface of the conductor pattern 21A is 19.5 mm, for example. That is, the dimension b = (a1-a2) / 2 is 0.25 mm. For example, when the conductor pattern 21A is formed by etching from a copper plate having a thickness of 2 mm, the dimension b is about 0.1 mm to 0.5 mm, although it depends on the etching conditions.

  The conductor pattern 21A is inserted into the groove 33 and connected to other power supply wiring or signal wiring to form the power supply wiring 21. The periphery of the power supply wiring 21 is fixed to the side wall of the groove 33 with the adhesive 22 (FIG. 5). 5A is a front view of the obtained printed wiring board 10, FIG. 5B is a back view of the obtained printed wiring board 10, and FIG. It is C sectional drawing. The tapered shape of the conductor pattern 21 </ b> A is suitable for the injection of the adhesive 22. The adhesive 22 attached around the groove 33 is removed by polishing or the like.

  Next, the copper foil 31 left around the power supply wiring 21 is patterned so as to form a desired wiring layer. This patterning is performed by a known method, for example, wet etching. Thus, the printed wiring board 10 shown in FIG. 1 in which the large current wiring 21, the signal wiring 13, and the land 12 are arranged at the same height is obtained. In the printed wiring board 10, for example, a semiconductor chip mounted on the printed wiring board 10 and a circuit component such as a chip resistor are connected to the land 12 by soldering. The wiring 21 is connected to an external power source. Further, the power supply wiring 21 on the back surface side is used, for example, as a power supply for components mounted on the back surface, or connected to the power supply wiring of the printed wiring layer laminated on the printed wiring board.

  A soldering method is used for mounting various circuit components and connecting to external wiring. Prior to the supply of solder, solder resist is supplied to the front and back surfaces of the printed wiring board. In this embodiment, substantially no step is formed between the land 12, the signal wiring 13 and the large current wiring 21, and the step between these and the insulating base material 11 is also small. Becomes easier. For this reason, good soldering becomes possible.

  The printed wiring board 10 of this embodiment can be used as a printed wiring board having two wiring layers even in the state of FIG. However, as shown in FIG. 6, for example, a printed wiring layer 41 made up of two insulating layers on the surface of which only a small current wiring 42 such as a signal wiring is sandwiched between the printed wiring boards 10 of FIG. It can be configured as a printed wiring board 50 having a structure. In the example of FIG. 6, the through hole 43 is formed after the printed wiring board 10 is sandwiched between the two printed wiring layers 41. The through hole 43 is formed by a drill method or the like after integrating both the printed wiring layers 41 including the signal wiring and the printed wiring board 10 sandwiched between them. A solid or hollow metal plug (not shown) is formed in the through hole 43 by, for example, plating.

  FIG. 7 is a cross-sectional view showing a main part of a printed wiring board according to the second embodiment of the present invention. In the printed wiring board 60 of this embodiment, the punching groove 34 is formed in the insulating base material 11, and the conductor pattern is inserted into the punching groove 34 to form the high current wiring 21. In the conductor pattern, when the width of the central portion of the groove 33 is a1, and the width in the vicinity of the surface of the groove 33 is a2, b = (a1−a2) / 2 is 0. It is about 1 to 0.5 mm. Due to the taper shape, injection into the gap from the front and back surfaces of the adhesive 22 is facilitated. For this reason, the fixing of the large current wiring 21 in the groove pattern 33 is performed in a simple process. In FIG. 7, only the large current wiring 21 is shown as the wiring. However, signal wiring and lands (not shown) similar to FIG. 1 are formed on the surface of the insulating base 11.

  In each of the embodiments described above, a configuration is adopted in which the conductor pattern for large current manufactured in a separate process is embedded in the groove pattern 33 formed in the insulating base material 11 constituting the core material. For this reason, a wiring layer in which a large current wiring and a general signal wiring are mixed on the same surface can be obtained. In this process, since the prepreg is not required to be laminated, the manufacturing process is simplified.

  In addition, since most of the high-current wiring is embedded in the core material, the unevenness on the surface is reduced, and the solder resist can be easily applied. For this reason, good soldering becomes possible.

  In the said embodiment, although the example which used the wiring material as copper was shown, the wiring material is not limited to copper, For example, aluminum, nickel, etc. can be used. Moreover, although the example in which the insulating substrate is an epoxy resin has been shown, it is not limited to this example as well.

  Although the invention has been particularly shown and described with reference to illustrative embodiments, the invention is not limited to these embodiments and variations thereof. It will be apparent to those skilled in the art that various modifications can be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims.

10, 50, 60: Printed circuit board
11: Insulating substrate (substrate)
12: Wiring land (land)
13: Signal wiring 14, 43: Through hole 21: High current wiring (power supply wiring)
21A: Conductive pattern 22: Adhesive 31: Copper foil 32: Copper foil removed portion 33: Groove (groove pattern)
34: Punching groove 41: Printed wiring layer 42: Small current wiring

Claims (8)

Etching a part of the conductor layer covering at least one surface of the insulating substrate to form a conductor layer removal pattern; and
Removing a portion in the conductor layer removal pattern of the insulating substrate to form a groove pattern;
Inserting a conductor pattern having a shape suitable for the groove pattern into the groove pattern;
Fixing at least a gap between the conductor pattern and the groove pattern;
Patterning the remaining portion of the conductor layer to form a wiring pattern.   The method for manufacturing a printed wiring board according to claim 1, wherein the conductor pattern is formed by etching.   The printed wiring board according to claim 1 or 2, wherein the conductor layer covers both surfaces of the insulating base material, and the conductor pattern is formed on both surfaces of the insulating base material, respectively. Method.   The method for manufacturing a printed wiring board according to claim 3, wherein a width of the conductor pattern adjacent to a bottom surface of the groove pattern is 0.1 mm to 0.5 mm wider than a width of a surface exposed from the groove pattern.   The method for manufacturing a printed wiring board according to claim 3 or 4, wherein the conductor patterns formed on both surfaces are connected to each other through a through hole.   The groove pattern is formed as a punched groove penetrating the insulating base material, and the conductor pattern has a width of a central portion accommodated in the groove pattern smaller than a width of a surface exposed from the groove pattern. The method for producing a printed circuit board according to claim 1, wherein the printed circuit board is 1 mm to 0.5 mm wide. An insulating substrate having a groove pattern formed on at least one surface;
A conductor pattern inserted into the groove pattern and fixed with an adhesive.
A printed wiring board comprising: a wiring pattern formed on a surface of the insulating base other than the groove pattern.   The printed wiring board according to claim 7, further comprising a pair of printed wiring layers sandwiching the insulating base material on which the conductor pattern and the wiring pattern are formed.

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