JP2005136172A - Multiple wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-piece wiring board that can be divided into individual wiring boards without causing mechanical destruction such as cracks and cracks at corners of each wiring board region.
A multi-cavity wiring board includes at least one of a ceramic mother board 1 having a plurality of rectangular wiring board regions 2 arranged vertically and horizontally on a main surface, and a main surface of the ceramic mother board 1 and a main surface opposite thereto. On the other hand, in the multi-piece wiring board 4 in which the dividing grooves 3 are provided vertically and horizontally along the boundary between the wiring board areas 2, the wiring board area 2 has through-holes 6 each having a square cross section at each corner. Each corner is chamfered in a planar shape by being formed so that each corner is positioned on the dividing groove 3, and the through-hole 6 has a hole 7 wider than the dividing groove 3 at each corner. Each is formed.
[Selection] Figure 1

Description

  The present invention relates to a multi-cavity wiring board in which a large number of wiring board regions on which electronic components such as semiconductor elements and surface acoustic wave elements are mounted are arranged vertically and horizontally in the center of the main surface of a large-area ceramic mother board. It is about.

  2. Description of the Related Art Conventionally, wiring boards used for mounting electronic components such as semiconductor elements and surface acoustic wave elements have been formed on the upper surface of a square plate-like insulating base made of a ceramic material such as an aluminum oxide sintered body (alumina ceramic). An electronic component mounting portion for mounting an electronic component is provided, and a plurality of wiring conductors made of a metal material such as tungsten are disposed from the mounting portion or its periphery to the lower surface of the insulating base. .

  Then, the electronic component is mounted and fixed on the mounting portion of the insulating base, and the electrode of the electronic component is electrically connected to the wiring conductor via an electrical connection means such as a bonding wire or solder, and the electronic component is attached as necessary. It becomes an electronic device as a product by hermetically sealing with a resin or a lid.

  With the recent demand for downsizing of electronic devices, the size of such wiring boards has become extremely small, about several mm square, and in order to facilitate the handling of wiring boards, In order to efficiently manufacture a wiring board and an electronic device, it is manufactured in the form of a so-called multi-cavity wiring board in which a large number of wiring boards are obtained collectively from a single large-area mother board. Yes.

  The multi-cavity wiring board generally has a structure in which a plurality of rectangular wiring board regions serving as a wiring board are formed in the central portion of the main surface of a flat ceramic mother board. In order to facilitate handling of the multi-piece wiring board, a structure in which a dummy area is formed on the outer periphery of the ceramic mother board so as to surround the wiring board area is also common.

  On at least one of the upper surface and the lower surface of the ceramic mother substrate where the wiring substrate regions are formed, dividing grooves are provided vertically and horizontally along the boundary between the wiring substrate regions. Then, by dividing the ceramic mother board along the dividing groove, individual wiring boards can be obtained. The division of the ceramic mother board along the dividing groove means that a bending stress is applied to the ceramic mother board along the dividing groove, and the ceramic mother board is broken at a portion along the dividing groove having a low mechanical strength.

  A multi-cavity wiring board is formed by first forming a raw material powder such as aluminum oxide into a sheet together with an organic binder to form a plurality of ceramic green sheets (hereinafter also referred to as green sheets), and then a conductive paste on each green sheet. Are printed in a pattern such as a predetermined wiring conductor and stacked vertically, and then, on the main surface of the green sheet laminate, dividing grooves are formed vertically and horizontally so as to partition each wiring board region, and then It is formed by firing this laminate.

  However, in such multi-cavity wiring boards, due to mechanical impact when the ceramic mother board is divided (broken) along the dividing grooves, there are cracks, cracks, etc. at the corners of the rectangular wiring board region. There was a problem that mechanical breakdown was likely to occur. For this reason, individual wiring boards manufactured in the form of multi-cavity wiring boards are prone to mechanical strength deficiencies, mechanical breakdowns such as cracks and cracks, and reliability such as hermetic sealing. The problem was low.

  To solve this problem, for each wiring board region, each corner of the wiring board region is formed by forming a through-hole having a square cross section at each corner so that each corner is positioned on the dividing groove. A means of chamfering the part in a flat shape can be considered. That is, by chamfering each corner of the wiring board region in a planar shape, even if a mechanical shock when dividing the ceramic mother board acts on each corner, the corner is chamfered, so mechanical As a result, it becomes difficult to cause destruction, and as a result, it is possible to secure the mechanical strength of each wiring board obtained by dividing, and effectively prevent the occurrence of mechanical destruction such as cracks and cracks. Can do.

In order to form a through-hole having a square cross section at each corner of the wiring board region so that each corner is positioned on the dividing groove, the multilayer structure of green sheets to be a multi-piece wiring board is used. Use a method such as punching with a rectangular punching pin, with the corners of the wiring board area centering on the intersection where the vertical and horizontal dividing grooves intersect and the corners are located on the dividing line. Can do.
JP 2000-114411 A

  However, as described above, for each wiring board region, each corner of the wiring board region is planarized by forming a through-hole having a square cross section at each corner so that each corner is positioned on the dividing groove. Even if chamfered in the shape, the formation positions of the dividing grooves and the through holes may be slightly shifted. In this case, the corners of the through holes are displaced from the dividing grooves. For this reason, the corners of the wiring board region cannot be chamfered in a flat shape, and instead the corners of the wiring board region are intricately complicated, and mechanical destruction such as cracks and cracks is likely to occur. It will cause problems. In addition, since the corners of the wiring board region are chamfered and the adjacent surfaces are angular, cracks and the like are likely to occur.

  In particular, recently, a glass ceramic sintered body that can be co-fired with a metal material having a low electrical resistance such as copper or silver has been widely used as a material for an insulating substrate. Since the mechanical strength of the sintered body is generally weaker than that of the aluminum oxide sintered body, the occurrence of mechanical destruction such as cracks and cracks as described above has become remarkable.

  Therefore, the present invention has been completed in order to solve the above-mentioned conventional problems, and its purpose is to form a large number of wiring board regions on the ceramic mother board and to extend along the boundary of each wiring board region. A multi-piece wiring board having a structure in which a dividing groove is formed. A multi-piece wiring board that can be divided into individual wiring boards without causing mechanical destruction such as cracks and cracks at the corners of each wiring board area. It is to provide a wiring board.

  The multi-cavity wiring board of the present invention is provided on at least one of a ceramic mother board in which a plurality of rectangular wiring board regions are vertically and horizontally arranged on the main surface, and the main surface of the ceramic mother board and the main surface facing the ceramic mother board. In a multi-piece wiring board in which dividing grooves are provided vertically and horizontally along the boundary between the wiring board areas, the wiring board area has a through-hole having a square cross section at each corner, and the corners are divided at the corners. Each corner is chamfered in a planar shape by being formed so as to be positioned on the groove, and the through-hole is formed with a hole having a width wider than that of the divided groove at each corner. It is characterized by this.

  According to the multi-cavity wiring board of the present invention, the dividing grooves are provided in the vertical and horizontal directions along the boundary between the wiring board areas, and the wiring board area has through-holes having a square cross section at each corner. Since each corner is chamfered in a flat shape by being formed so that each corner is positioned on the dividing groove, even if a mechanical shock when dividing the ceramic mother substrate acts on each corner Since the corners are chamfered in a flat shape, mechanical destruction is less likely to occur.

  Further, according to the multi-cavity wiring board of the present invention, since the through holes are formed with holes (notches) wider than the divided grooves at the respective corners, the divided grooves and the through holes are formed. Even if the formation position is slightly deviated, each of the wiring board regions to be divided does not have an angular shape between the chamfered surface and the adjacent surface, and the dividing groove passes through the hole. The corners of can be chamfered with a surface that is smoothly and continuously connected from the through hole to the hole. As a result, for each wiring board obtained by division, the corners are formed with smooth and continuous surfaces regardless of whether or not the formation positions of the dividing grooves and through-holes are shifted. The strength can be ensured and the occurrence of mechanical destruction such as cracks and cracks can be effectively prevented.

  The multi-piece wiring board of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a plan view showing an example of an embodiment of a multi-cavity wiring board according to the present invention. In FIG. 1, 1 is a ceramic mother board, 2 is a wiring board region, and 3 is a dividing groove. A multi-piece wiring board 4 is mainly constituted by the ceramic mother board 1, the wiring board region 2 and the dividing groove 3.

  The ceramic mother substrate 1 is made of a ceramic material such as an aluminum oxide sintered body (alumina ceramic), a mullite sintered body, an aluminum nitride sintered body, a silicon carbide sintered body, or a ceramic such as a glass ceramic sintered body. Become. The ceramic mother board 1 has a plurality of rectangular wiring board regions 2 arranged vertically and horizontally on the main surface. Further, at least one of the main surface of the ceramic mother substrate 1 and the main surface opposite to the main surface is provided with dividing grooves 3 vertically and horizontally along the boundary between the wiring board regions 2. By dividing the mother board 1, the wiring board region 2 is divided into individual wiring boards.

  When the ceramic mother substrate 1 is made of, for example, an aluminum oxide sintered body, an appropriate organic binder, plasticizer, solvent, etc. are added to and mixed with raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide and the like. The slurry is made into a plurality of green sheets (raw sheets) by the doctor blade method or the calender roll method, and then these green sheets are appropriately punched and laminated, and then the green sheets A plurality of wiring board regions are arrayed by dividing the main surface of the laminate in vertical and horizontal directions, and at least one of the main surface and the main surface opposite to the main surface is cut vertically and horizontally along the boundary between the wiring board regions. It is produced by forming a dividing groove and finally firing the laminated body at a temperature of about 1600 ° C.

  Each wiring board region 2 of the ceramic mother board 1 has a wiring conductor 5 formed on the surface and inside thereof. Then, for example, an electronic component (not shown) is mounted on the surface of each wiring board region 2, and the electrode of the electronic component is electrically connected to the exposed portion of the wiring conductor 5 via a bonding wire, solder, or the like. Thus, a large number of electronic devices are arranged and formed, and by dividing the ceramic mother substrate 1 along the dividing grooves 3, a large number of electronic devices are simultaneously and collectively manufactured.

  The electronic components may be mounted individually on each wiring board after the multi-cavity wiring board 4 is divided into the individual wiring board regions 2 to form a large number of wiring boards.

  In the multi-cavity wiring board 4 of the present invention, as shown in FIG. 2, the wiring board region 2 has a through-hole 6 having a square cross section at each corner so that each corner is positioned on the dividing groove 3. In this way, each corner is chamfered in a planar shape, and the through-hole 6 is formed with a hole 7 wider than the dividing groove 3 at each corner. With this configuration, even if a mechanical shock when dividing the ceramic mother board 4 acts on the corners of each wiring board region 2, the corners are chamfered in a flat shape, so that mechanical breakdown is unlikely to occur. Become.

  Moreover, since the hole (notch part) 7 wider than the division | segmentation groove | channel 3 is each formed in each corner of the through-hole 6, even if the formation position of the division | segmentation groove | channel 3 or the through-hole 6 has shifted | deviated somewhat, The corner portion of each wiring board region 2 to be divided does not have an angular shape between the chamfered surface and the adjacent surface, and the dividing groove 3 passes through the hole portion 7. It is possible to chamfer at a surface that is smoothly and continuously connected from the through hole 6 to the hole portion 7. As a result, for each wiring board obtained by dividing the multi-cavity wiring board 4 of the present invention, the mechanical strength is surely ensured regardless of whether or not the formation positions of the dividing grooves 3 and the through holes 6 are shifted. In addition, it is possible to effectively prevent the occurrence of mechanical destruction such as cracks and cracks.

  The through hole 6 preferably has a square cross-sectional shape (opening shape). In this case, since the length of each side of the wiring board region 2 becomes the same quadrangle, when the ceramic mother board 4 is divided, the mechanical stress is evenly distributed, and mechanical parts such as cracks and cracks are more surely obtained. Generation | occurrence | production of destruction etc. can be prevented effectively.

  If the size of the through hole 6 is such that it does not enter the part of the wiring board region 2 where the wiring conductor 5 is formed, the size (side length) of the wiring board region 2 or the ceramic mother board What is necessary is just to determine suitably according to the thickness etc. of 1.

  It is preferable that the hole 7 formed at each corner of the through hole 6 passes through the ceramic mother substrate 1. When the hole 7 penetrates the ceramic mother board 1, when the ceramic mother board 4 is divided, there is no place where mechanical stress is concentrated in the thickness direction of the hole 7, and a machine such as cracks and cracks is more reliably obtained. Can be prevented from occurring.

  Moreover, it is preferable that the hole part 7 is elliptical shape (semi-elliptical shape) in which a long axis is located along the dividing groove 3. By forming the hole 7 in such a shape, when the ceramic mother substrate 4 is divided, mechanical stress is concentrated on the tip of the hole 7 so as to extend from the tip of the hole 7 along the dividing groove 3. Therefore, the occurrence of mechanical destruction such as cracks and cracks can be prevented more reliably without division starting from other portions.

  As a method of forming the hole portions 7 at the respective corners of the through-holes 6, the through-holes 6 are formed by punching a green sheet or a laminate thereof serving as the ceramic mother substrate 1, and then each of the through-holes 6 is formed. A method such as punching with a constant width from the corner portion to the outside can be used.

  Further, the metallized layer may be attached to the inner surface of the through hole 6 or the hole 7. In this case, the inner surface of the through-hole 6 and the hole 7 can be protected to improve toughness, and the occurrence of cracks, cracks, and the like can be more effectively prevented.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, a plating layer of nickel, gold, or the like is deposited on the exposed surface of the wiring conductor 5 to effectively prevent oxidative corrosion of the wiring conductor 5, and bondability of the bonding wire to the wiring conductor 5, solder wettability, etc. You may make it improve.

It is a top view which shows an example of embodiment of the multi-piece wiring board of this invention. It is a principal part enlarged plan view of the multi-piece wiring board shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ceramic mother board 2 ... Wiring board area | region 3 ... Dividing groove 4 ... Multi-piece wiring board 5 ... Wiring conductor 6 ... Through-hole 7 ... Hole

Claims (1)

At least one of the main surface of the ceramic mother substrate in which a plurality of square-shaped wiring substrate regions are arranged vertically and horizontally on the main surface and the main surface of the ceramic mother substrate and the main surface opposite thereto, along the boundary between the wiring substrate regions In the multi-piece wiring board provided with dividing grooves in the vertical and horizontal directions, the wiring board region is formed such that through holes having a square cross section are formed at each corner so that each corner is positioned on the dividing groove. Thus, each corner is chamfered in a planar shape, and the through hole is formed with a hole having a width wider than that of the dividing groove at each corner, respectively. .

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