WO2008075686A1

WO2008075686A1 - Wiring board and method for manufacturing the same

Info

Publication number: WO2008075686A1
Application number: PCT/JP2007/074325
Authority: WO
Inventors: Keiichi Morikane; Satoshi Nagao
Original assignee: Koa Corporation
Priority date: 2006-12-18
Filing date: 2007-12-18
Publication date: 2008-06-26
Also published as: JP2008153441A

Abstract

[PROBLEMS] To provide a wiring board, which permits plating to be performed over the entire surface of a castellation conductor in a state of a large substrate for taking out many wiring boards, and can be excellently divided from the substrate, and to provide a method for manufacturing such wiring board. [MEANS FOR SOLVING PROBLEMS] A large substrate (28) is divided into many wiring boards (11). In the wiring board, a castellation conductor (15) is arranged in notches (13, 14) on the side surface of a ceramic substrate (12). A plating layer (16) is applied on the entire surface of the castellation conductor (15). The both end portions of the notches (13, 14) in the width direction, however, are exposed wall surfaces (13a, 14a) not coated with the castellation conductor (15). Therefore, each castellation conductor (15) is separated from the side surface of the ceramic substrate (12).

Description

Specification

Wiring board and manufacturing method thereof

Technical field

TECHNICAL FIELD [0001] The present invention relates to a wiring board obtained from a large number of large-sized boards and a manufacturing method thereof, and in particular,

The present invention relates to an improvement in castor conductor (side conductor) provided on the side surface of the wiring board. Background art

[0002] Generally, a wiring board on which an electronic circuit element such as a semiconductor element is mounted is obtained by dividing a large-sized board obtained by firing a green sheet laminate along vertical and horizontal dividing lines. It is supposed to be. In this large substrate, a large number of wiring board regions are partitioned by dividing lines, and wiring patterns and caster conductors are provided in each wiring board region. Here, the caster conductor is a force provided on the inner wall of the through-hole drilled in the dividing line in a large-sized substrate. Since the dividing surface along this dividing line is the side surface of each wiring substrate, there are a large number of caster conductors. A castor conductor is formed on the wall surface in the recessed groove on the side surface of the removed wiring board. The caster conductor and the wiring pattern are connected at appropriate places, and connected to the wiring pattern by electronic circuit element force S wire bonding or the like mounted on the upper surface of the wiring board, and the mother board on which the wiring board is mounted. The caster conductor is soldered on the solder land of the board. As a result, the electronic circuit element on the wiring board is electrically connected to the external circuit via the caster conductor.

FIG. 6 is a perspective view showing a caster conductor of a conventional wiring board. In the wiring board 1 shown in the figure, concave cutouts 3 and 4 are provided on the side surface of the ceramic substrate 2, and a highly conductive material such as silver is formed on the wall surfaces of the cutouts 3 and 4. A caster conductor 5 having a predetermined thickness is formed. Although not shown, a wiring pattern connected to the caster conductor 5 is provided on the inner layer and the outer layer of the wiring board 1, and an electronic circuit element is mounted on the upper surface of the wiring board 1. These electronic circuit elements and wiring patterns are connected by wire bonding or the like. Normally, the surface of the caster conductor 5 is knitted to improve solder wettability and prevent silver solder erosion. A not-shown plating layer such as a Kell layer is applied (see, for example, Patent Document 1).

FIG. 7 is an explanatory view showing a manufacturing process of the conventional wiring board shown in FIG. A large substrate 6 shown in FIG. 7 is obtained by firing a laminate of green sheets on which necessary conductive portions are formed, and is divided by vertical and horizontal dividing lines 7 and 8. A large number of wiring boards 1 are obtained by dividing the large-sized board 6 along the dividing lines 7 and 8 so as to correspond to the board 1. The large substrate 6 has a number of through holes 10 at predetermined positions overlapping the dividing lines 7 and 8, and an undivided caster conductor 5 having a predetermined thickness is formed on the inner wall of each through hole 10. Is provided. In other words, since the divided surface along the dividing lines 7 and 8 is the side surface of each wiring substrate 1 in this large-sized substrate 6, the through-hole 10 is divided into two parts on the side surface of the wiring substrate 1 that has been removed. The caster conductor 5 is provided on each of the inner wall of the notch 3 and the inner wall of the notch 4 divided into four parts. When forming the castor conductor 5 on the inner wall of the through hole 10, after filling the through hole 10 with a conductive material such as silver paste, the through hole 10a is formed in the center of the through hole 10. By providing and removing a part of the conductive material, an undivided caster conductor 5 having a predetermined thickness can be formed by the remaining conductive material.

Patent Document 1: Japanese Unexamined Patent Publication No. 2003-179176 (Page 3-5, Fig. 3)

Disclosure of the invention

Problems to be solved by the invention

[0005] As described above, the caster conductor 5 of the wiring board 1 that is taken in large numbers from the large board 6 is formed on the inner wall of the through hole 10 that overlaps the dividing lines 7 and 8, so that the large board 6 Even if a plating process is applied to the caster conductor 5 before dividing it, the end face (split surface) of the caster conductor 5 that matches the dividing line 7 and the dividing line 8 remains on the plating layer. It becomes a non-sticky area that does not exist. Then, if the wiring board 1 is mounted on the mother board while the end face of the castor conductor 5 is not scratched, the silver component in the caster conductor 5 will cause solder erosion at the end face. Is significantly reduced.

[0006] Therefore, in order to prevent the solder component of the silver component in the caster conductor 5 from being eroded, it is necessary to subject the individual pieces (wiring board 1) obtained by dividing the large board 6 to a plating process. This As a result, not only the work efficiency is reduced compared to the plating process performed in the state of the large-sized substrate 6, but also the process after the plating process in which an electronic circuit element is mounted and the continuity test is performed is in the state of the large-sized substrate 6. In this case, it becomes impossible to implement, and productivity is reduced and manufacturing costs are inevitably increased.

[0007] In the conventional manufacturing method, the large-sized substrate 6 is divided by a method such as half-cutting or dicing while the dividing lines 7 and 8 and the caster conductor 5 are overlapped. Since there is a force S, and the part where ceramic and metal are mixed becomes a split surface, there is a problem in that the split property is difficult, and there is a problem that burrs, chips, dirt, etc. are likely to occur on the split surface.

[0008] The present invention has been made in view of such a state of the art, and a first object of the present invention is to perform a plating process on the entire surface of a caster conductor in the state of a large-sized substrate for multi-piece production. An object of the present invention is to provide a wiring board that can be applied and has good division. In addition, a second object of the present invention is to provide a method for manufacturing a wiring board that is powerful.

Means for solving the problem

[0009] In order to achieve the first object, in the present invention, in the present invention, a grooved notch extending to both the upper and lower surfaces is provided on the side surface of the ceramic substrate, and a plating layer is provided on the wall surface in the notch. A wiring board having a plurality of ceramic substrates taken by dividing a large-sized substrate along a dividing line, the notches of the ceramic substrate having a width thereof A pair of exposed wall surfaces that are not covered by the caster conductor and located at both ends of the direction, and a coated wall surface that is located between the pair of exposed wall surfaces and is covered by the caster conductor. The caster conductor provided on the side wall is separated from the side surface via the exposed wall surface.

[0010] In the wiring board configured as described above, since the castor conductor provided on the inner wall of the cutout on the side surface of the ceramic substrate is separated from the side surface via the exposed wall surface of the cutout, In the state of a large-sized substrate for taking a large number of pieces, a plating layer can be deposited on the entire surface of the castor conductor conductor exposed without overlapping the dividing lines. Therefore, the working efficiency of the plating process applied to the caster conductor is improved, and the post-meshing process of mounting an electronic circuit element and conducting continuity inspection etc. can be performed in the state of a large substrate. As a result, productivity can be significantly increased without impairing reliability. In addition, since the dividing line of the large substrate and the caster conductor do not overlap, the dividing property is improved, and therefore, the dividing surface becomes clogged, chipped, soiled, and the like.

In the wiring board having the above configuration, the ceramic substrate may be a single layer. However, if the ceramic substrate is a multilayer substrate, it is preferable because it can be applied to a general wiring substrate.

[0012] In order to achieve the second object, in the method for manufacturing a wiring board according to the present invention, a through hole for a caster conductor is provided at a predetermined position including the vicinity of a dividing line of a multi-sheet green sheet. A conductive material filling step for filling the through holes with a conductive material, and after the conductive material filling step, through holes that partially overlap the through holes across the dividing line are formed. A castoration conductor that is spaced apart from the dividing line by filling the recess not overlapping with the through-hole at the peripheral edge in the through-hole by punching in the green sheet; And a caster conductor forming process for cutting off the conductive material filled in the other part of the through-hole, and the caster guide A firing process for firing the green sheet after the forming process to obtain a large-sized substrate for taking a large number of pieces, a plating process for depositing a plating layer on the surface of the caster conductor conductor after the firing process, and the plating process And a dividing step of dividing the large substrate into individual pieces along the dividing line, and a plurality of wiring boards having the caster conductors are taken by the dividing step.

[0013] In such a method of manufacturing a wiring board, after filling a through hole for a caster conductor with a conductive material, a through hole that crosses the dividing line and partially overlaps the through hole is formed in a green sheet. The conductive material that faces the through hole is left in the recess separated from the dividing line at the peripheral edge in the through hole, so that the conductive material can be used as a caster conductor. Therefore, before dividing a large-sized board for multi-piece production into pieces, a plating layer can be applied to the entire surface of the castor conductor of each wiring board, and a process for applying a process to the caster conductor. As well as improving the work efficiency, the post-processing process of mounting electronic circuit elements and conducting continuity tests, etc., can also be performed in the state of a large substrate, greatly improving productivity without sacrificing reliability. High The ability to turn S is possible. Also, since the dividing line of the large-sized substrate and the caster conductor do not overlap each other, the dividing property is improved, so that the dividing surface is less likely to be clogged, chipped or soiled.

[0014] In the above manufacturing method, after the caster conductor formation process, a multilayer body forming process is performed in which a plurality of green sheets are stacked and thermocompression bonded. If it is made into a multilayer substrate, since it can apply to manufacture of a general wiring board, it is preferable.

The invention's effect

[0015] In the wiring board of the present invention, the caster conductor provided on the inner wall of the cutout on the side surface of the ceramic substrate is separated from the side surface via the exposed wall surface of the cutout. In the state of a large substrate, a plating layer can be applied to the entire surface of the castor conductor conductor exposed without overlapping the dividing lines. Therefore, the working efficiency of the plating process performed on the caster conductor is improved, and the post-etching process, in which an electronic circuit element is mounted and a continuity test is performed, can be performed in the state of a large substrate. As a result, productivity can be significantly increased without impairing reliability. Further, since the dividing line of the large-sized substrate and the caster conductor do not overlap, the dividing property is improved, so that the dividing surface becomes clogged, chipped, soiled or the like.

[0016] Further, in the method for manufacturing a wiring board according to the present invention, after filling a through hole for a caster conductor with a conductive material, a through-hole that partially overlaps the through-hole across a dividing line is formed. By piercing the green sheet, the conductive material facing the through hole is left in a recess separated from the dividing line at the peripheral edge in the through hole, and the conductive material is made into a castor conductor. Can do. Therefore, before dividing the large-sized substrate for multi-piece production into pieces, a plating layer can be applied to the entire surface of the castor conductor of each wiring board, and a process for applying a process to the caster conductor. In addition to improving work efficiency, the post-processing process of mounting electronic circuit elements and conducting continuity tests, etc., can also be performed in the state of a large substrate, greatly improving productivity without sacrificing reliability. Can be increased. In addition, since the dividing line of the large substrate and the caster conductor do not overlap each other, the dividing property is improved, so that the dividing surface is free of chips, chips, dirt, etc. It becomes <<

BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a caster conductor of a wiring board according to an embodiment of the present invention, and FIG. 2 is a diagram of the caster conductor. Cross-sectional views and FIGS. 3 to 5 are manufacturing process diagrams of the wiring board.

A wiring board 11 shown in FIGS. 1 and 2 includes a multilayer ceramic substrate 12 on which an electronic circuit element (not shown) is mounted on the upper surface, and not shown provided on an inner layer and an outer layer of the ceramic substrate 12. A wiring pattern and a caster conductor 15 having a good conductive material such as silver provided on inner walls of the cutouts 13 and 14 on the side surface of the ceramic substrate 12 are provided. Of the inner walls of the notches 13 and 14, both end portions in the width direction are exposed wall surfaces 13 a and 14 a that are not covered with the caster conductor 15. Further, the coated wall surfaces 13b and 14b of the notches 13 and 14 coated on the caster conductor 15 are formed deeper and grooved than the exposed wall surfaces 13a and 14a, respectively. The wiring pattern of this wiring board 11 is connected to caster conductors 15 at appropriate places, and this wiring pattern and electronic circuit elements are connected by wire bonding or the like. Further, since the caster conductor 15 is soldered on a solder land of a mother board (not shown) on which the wiring board 11 is mounted, the electronic circuit elements on the wiring board 11 pass through the caster conductor 15. It will be electrically connected to the external circuit. In order to improve solder wettability and prevent silver solder erosion, a plating layer 16 made of nickel, gold or the like is deposited on the entire surface of the caster conductor 15.

[0019] The structure of the caster conductor 15 will be described in detail. On the side surface of the ceramic substrate 12, a notch 13 formed by dividing a through hole 23 described later into two and a through hole 24 described later are divided into four. Notches 14 are provided at a plurality of locations. In each of the notches 13 and 14, caster conductors 15 are provided at the innermost portions where the covering wall surfaces 13b and 14b are formed. The notches 13 and 14 are each formed in the shape of a concave groove extending to both the upper and lower surfaces of the ceramic substrate 12. The caster conductor 15 covering the coated wall surface 13b in the notch 13 is a pair of exposed wall surfaces 13a. , 13a, and a substantially semi-cylindrical surface is formed by the surface of the caster conductor 15 and both exposed wall surfaces 13a. It is. Similarly, the castor conductor 15 that covers the coated wall 14b in the notch 14 is exposed between the pair of exposed walls 14a and 14a, and the surface of the caster conductor 15 and both exposed walls 14a As a result, a quadruple cylindrical surface is formed. Therefore, the castor conductor 15 in the notch 13 is separated from the side surface of the ceramic substrate 12 via the exposed wall surface 13a, and the castor conductor 15 in the notch 14 is separated from the ceramic substrate via the exposed wall surface 14a. Separated from 12 sides.

[0020] As will be described later, a large number of wiring boards 11 are obtained by dividing the large board 28 (see FIG. 5) along the dividing lines 21 and 22, so that the divided surface of the large board 28 is the wiring board. 11th aspect. Since the side surface of the wiring board 11 and the caster conductors 15 in the notches 13 and 14 are separated from each other through the exposed wall surface 13a and the exposed wall surface 14a, each wiring board 11 in the state of the large board 28. The caster conductor 15 can be separated from the destructive IJ lines 21 and 22 in advance. In other words, since the wiring board 11 can be exposed by forming caster conductors 15 at positions where they do not overlap with the dividing surface during the manufacturing process, The plating layer 16 can be applied to the entire surface of the caster conductor 15 of the wiring board 11.

[0021] The manufacturing method of the wiring board 11 will be described in detail. First, as shown in FIG. 3 (a), punching is performed at a predetermined position where it overlaps with the vertical and horizontal dividing lines 21 and 22 of the multi-sheet green sheet 20. A number of through-holes 23 and 24 for caster conductor 15 are drilled by a machine. At this time, the through hole 23 that overlaps only the dividing line 21 or only the dividing line 22 is formed into a hole having a shape of figure 8 in plan view by connecting two round holes. On the other hand, the through hole 24 that overlaps the intersecting part of the harm ij lines 21 and 22 has a shape like a four-leaf clover in plan view by connecting four round holes. Also, when drilling these through holes 23, 24, do not drill through holes for wiring patterns (not shown).

Next, as shown in FIG. 3 (b), silver paste 25 is filled into the snorkel wheels 23 and 24 and the wiring pattern through holes. After that, as shown in FIG. 3 (c) and FIG. 4 which is an enlarged view of the A part thereof, the round hole-shaped through hole 26 that partially overlaps the through hole 23 across the dividing line 21 or the dividing line 22 is obtained. Through the dividing line 21 and dividing line 22. The green sheet 20 is drilled with a round hole-shaped through hole 27 that partially overlaps the tool 24. By providing the through-hole 26 in this way, the silver paste 25 in the through-hole 23 is filled in the crescent-shaped recess 23a in plan view that does not overlap with the through-hole 26 and is separated from the dividing lines 21 and 22. ! /, Only the silver paste 25 remains and becomes the castor conductor 15, and the silver paste 25 filled in the other part of the through hole 23 is the green that exists between the other part and the adjacent dividing line. The sheet 20 is cut together with the wall. In other words, caster conductors 15 are formed at two opposite positions by punching the silver paste 25 in the through hole 23 through the through hole 26, and formed between each caster conductor 15 and the adjacent dividing line. The inner wall of the through-hole 26 is the exposed wall surface 13a. In addition, since the inner wall of the remaining through hole 23 becomes the covering wall surface 13b, the through hole 26 and the through hole 23 form a hole having a shape in which the two notches 13 face each other and communicate with each other. It will be.

Similarly, by providing the through hole 27, the silver paste 25 in the through hole 24 does not overlap with the through hole 27 and is separated from the dividing lines 21 and 22. Only the silver paste 25 filled in 24a remains and becomes the castor conductor 15, and the silver paste 25 filled in the other part of the through hole 24 has a dividing line adjacent to the other part. It is cut out together with the wall of the green sheet 20 existing between the two. In other words, caster conductors 15 are formed at four equally spaced locations by punching the silver paste 25 in the through holes 24 through the through holes 27, and between the caster conductors 15 and the adjacent divided lines. The inner wall of the formed through hole 27 becomes the exposed wall surface 14a. Further, since the inner wall of the remaining through hole 24 becomes the covering wall surface 14b, the through hole 27 and the through hole 24 form a hole having a shape in which the four notches 14 face each other and communicate with each other. It will be.

[0024] Thereafter, the wiring pattern or the like is printed on the green sheet 20, and then a predetermined number of green sheets 20 are stacked on a stacking jig (not shown), which is not shown in a vacuum pack state. It is made into a laminated body by putting in a press machine and thermocompression bonding. Then, by firing this laminate, a large-sized substrate 28 for multi-piece production as shown in FIG. 5 is obtained. This large substrate 28 has a small area 29 divided by vertical and horizontal dividing lines 21 and 22 and each wiring. Corresponds to board 11.

Next, nickel plating or gold plating is applied to the conductor portion exposed on the surface of the large substrate 28, and the plating layer 16 is attached to each caster conductor 5. At this time, the castor conductors 15 in the respective small regions 29 are not overlapped with the dividing lines 21 and 22 and are exposed to the through holes 26 and the through holes 27. Therefore, the caster conductors 15 in the state of the large substrate 28 are formed. A plating layer 16 can be applied to the entire surface of the substrate. Thereafter, by dividing the large substrate 28 along the dividing lines 21 and 22, a large number of wiring substrates 11 as shown in FIGS. 1 and 2 can be obtained. In this dividing step, the dividing surface of the large substrate 28 along the dividing lines 21 and 22 becomes the side surface of each wiring substrate 11. Further, the through hole 26 is divided into two parts to form the notches 13 of the respective wiring boards 11, and the through hole 27 is divided into four parts to form the notches 14 of the respective wiring boards 11.

As described above, in the present embodiment example, in the process of manufacturing the wiring substrate 11, the silver paste (conductive material) 25 is filled in the through holes 23 and 24 for the castor conductor 15, and then divided. By drilling through holes 26 and 27 in the green sea ridges 20 that cross the lines 21 and 22 and partially overlap the through holes 23 and 24, the recesses 23a and 24a in each of the snorley wheels 23 and 24 are formed. The caster conductor 15 can be formed on the front. These caster conductors 15 are exposed to the through holes 26 and 27 so as to be separated from the destructive IJ lines 21 and 22, so that before the large-sized substrate 28 for taking a large number of pieces is divided into pieces, The force S can be applied to the plating layer 16 on the entire surface of the caster conductor 15 of each wiring board 11. Therefore, the working efficiency of the plating process performed on the caster conductor 15 is improved, and the electronic circuit element is mounted to conduct a continuity test, etc., and the process after the plating process is also in the state of the large board 28. Can be implemented. Therefore, the silver component in the caster conductor 15 can be prevented from being eroded by solder and the reliability can be ensured, and the productivity can be greatly increased. However, since the dividing lines 21 and 22 and the caster conductor 15 do not overlap each other, the large-sized substrate 28 has a good dividing property, and therefore, the dividing surface is less likely to be chipped or soiled. The improvement of the non-defective product rate can be expected.

[0027] In the present embodiment, in the punching process of the through holes 26, 27 performed to form the castor conductor 15, the separations other than the recesses 23a, 24a in the snorley wheels 23, 24 are performed. Since the existing silver paste (conductive material) 25 is cut together with the wall portion of the adjacent green sheet 20, there is no possibility that the silver paste 25 remains in an undesired location. Moreover, the through holes 23, 24 and the through holes 26, 27 can be accurately drilled with a normal punching machine or the like. Therefore, it is easy to form a desired caster conductor 15, and high reliability is easily ensured.

[0028] It should be noted that the shape of the snorley wheel 23, 24 and the through holes 26, 27 can be selected as appropriate. In short, the portions of the through holes for caster conductors that do not overlap with the through holes are filled. Depending on the conductive material, the shape is such that a castor conductor is formed that is separated from the dividing line of the large substrate and exposed to the through hole! /!

[0029] Further, in the above embodiment, the power described in connection with the wiring substrate 11 in which the ceramic substrate 12 is a multilayer substrate and the manufacturing method thereof, and the present invention can be applied even if the ceramic substrate is a single-layer wiring substrate. Needless to say.

Brief Description of Drawings

FIG. 1 is a perspective view showing a caster conductor of a wiring board according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the caster conductor.

FIG. 3 is a manufacturing process diagram of the wiring board.

FIG. 4 is an enlarged view of part A in FIG.

FIG. 5 is a manufacturing process diagram of the wiring board.

FIG. 6 is a perspective view showing a caster conductor of a conventional wiring board.

7 is an explanatory view showing a manufacturing process of the conventional wiring board shown in FIG. 6.

Explanation of symbols

[0031] 11 Wiring board

12 Ceramic substrate

13, 14 notch

13a, 14a Exposed wall

13b, 14b coated wall

15 Castor conductor Metsuki layer

Green sheet, 22 split lines, 24 snorho honore, 24a recess

Silver paste (conductive material), 27 Through hole

Large format board

Claims

The scope of the claims

[1] A ceramic substrate provided with a concave groove-like notch extending on both upper and lower sides on a side surface and a castor conductor conductor provided on a wall surface in the notch and having a plating layer attached thereto, In a wiring board where a large number of ceramic substrates are taken by dividing a large substrate along the dividing line,

The notches of the ceramic substrate are located at both ends in the width direction and are covered with the caster conductors between a pair of exposed wall surfaces not covered with the caster conductors, and between the exposed wall surfaces. A wiring board, wherein the caster conductor provided on the coated wall surface is spaced from the side surface via the exposed wall surface.

[2] The arrangement according to claim 1, wherein the ceramic substrate is a multilayer substrate.

/ 锒 board.

[3] A conductive material filling step in which a number of through holes for castor conductors are drilled at predetermined positions including the vicinity of the dividing line of a multi-sheet green sheet, and the through holes are filled with a conductive material.

After the conductive material filling step, a through-hole that partially overlaps the through-hole across the dividing line is formed in the green sheet so that it does not overlap the through-hole at a peripheral edge in the through-hole. A caster conductor conductor forming step for forming a caster conductor that is spaced apart from the dividing line, and cutting off the conductive material that is filled in the other part of the through hole. When,

A firing step of firing the green sheet after the caster conductor forming step to obtain a large-sized substrate for multiple pieces,

A plating step of depositing a plating layer on the surface of the caster conductor after the firing step;

A dividing step of dividing the large-sized substrate into pieces along the dividing line after the mating step,

In the dividing step, a large number of wiring boards having the caster conductor are obtained. A method of manufacturing a wiring board, characterized by being made.

4. The method according to claim 3, wherein after the caster conductor formation step, a plurality of green sheets are laminated and subjected to thermocompression bonding, and the firing step is performed after the laminate formation step. A method of manufacturing a wiring board, characterized in that the board is a multilayer board.