JP2005217099A - Multicavity wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multicavity wiring board, in which even if a force is applied from an outside, an occurrence of unexpected cracks starting from the end of a divided trench is prevented, and electronic components can accurately and reliably be mounted onto each wiring board area of an insulating board. <P>SOLUTION: In the multicavity wiring board, a plurality of wiring board areas 2 are vertically and laterally arranged at the center of a planar insulating board 1, and also a divided trench 4 is formed along a boundary of the wiring board areas 2 on at least one main face of the insulating board 1. On the insulating board 1, a frame-shaped metal layer 5 is formed over all peripheries in the outer peripheral part of the main face or an inner layer, also a notch 5a is formed at a region opposing to a front end of the divided trench 4 in an inner periphery of the metal layer 5, and the front end of the divided trench 4 is entered into the inside of the notch 5a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a multi-cavity wiring board formed by arranging a large number of wiring board regions each serving as a wiring board for mounting electronic components such as semiconductor elements and crystal resonators in a large-area mother board. It is.

  Conventionally, wiring boards for mounting electronic components such as semiconductor elements and crystal resonators have a high melting point metal powder such as tungsten or molybdenum on the surface of an insulating base made of an electrically insulating material such as an aluminum oxide sintered body. It is formed by disposing a wiring conductor made of metallization.

  And while mounting an electronic component on a wiring board, each electrode of this electronic component is electrically connected to a wiring conductor through electrical connection means such as solder or bonding wire, and then, on this wiring board. A lid made of metal or ceramics or a potting resin is joined so as to cover the electronic component, whereby the electronic component is hermetically sealed, and an electronic device as a product is manufactured.

  By the way, such a wiring board has become extremely small with a size of about several mm square in accordance with the recent demand for miniaturization of electronic devices.

  Therefore, in order to facilitate the handling of such a small-sized wiring board and to efficiently manufacture the wiring board and an electronic device using the wiring board, a so-called multi-cavity wiring board is used. Made in form.

  Such a multi-piece wiring board is formed by integrally arranging a large number of wiring board regions 12 each having a wiring conductor 16 vertically and horizontally on a single large-area insulating substrate 11. After the electronic components are mounted and sealed, the insulating substrate 11 is divided into each wiring board region 12 so that a large number of electronic devices can be obtained simultaneously and collectively.

In such a multi-cavity wiring board, a ceramic green sheet for the insulating substrate 11 is prepared, and at least one main surface of the ceramic green sheet is divided into grooves having a constant width and depth by a cutter blade or a mold. The notch for 14 is formed along the boundary of the wiring board, and is manufactured by firing at a high temperature. By bending this along the dividing groove 14, it can be obtained as a large number of wiring boards and electronic devices.
Japanese Patent No. 2922285

  However, according to the conventional multi-cavity wiring board, the dividing groove 14 is formed for each of the plurality of wiring board areas 12 in the wiring board area 12. When an external force is applied when mounting the electronic component, the force concentrates on the end B of the dividing groove 14 and the insulating substrate 11 is inadvertently cracked starting from the end B. As a result, there has been a problem that it is impossible to mount electronic components such as a semiconductor element and a crystal resonator on each wiring board region 12 of the insulating substrate 11 accurately and reliably.

  Accordingly, the present invention has been completed in view of the above-described conventional problems, and its purpose is to start from the end of the dividing groove even when an external force is applied during transportation or mounting of an electronic component. A multi-piece wiring board that can prevent the occurrence of inadvertent cracking and can accurately and surely mount electronic components such as semiconductor elements and crystal units in each wiring board area of the insulating board. It is to provide.

  In the multi-cavity wiring board of the present invention, a plurality of wiring board regions are arranged vertically and horizontally at the center of a flat insulating substrate, and at least one main surface of the insulating substrate is provided with the wiring board region. A multi-piece wiring board in which dividing grooves are formed along a boundary, wherein the insulating substrate has a frame-like metal layer formed on the outer periphery of the main surface or inner layer, and the metal A notch is formed in a portion of the inner periphery of the layer facing the tip of the dividing groove, and the tip of the dividing groove is inserted into the notch.

  In the multi-cavity wiring board of the present invention, preferably, the metal layer is electrically connected to a wiring conductor formed in the wiring board region, and an exposed surface of the wiring conductor is electroplated. A conductive path for depositing the plating layer is formed.

  In the multi-piece wiring board of the present invention, the insulating substrate has a frame-like metal layer formed on the outer periphery of the main surface or the inner layer over the entire periphery, and faces the tip of the dividing groove at the inner periphery of the metal layer. Since the notch is formed in the part to be cut, and the dividing groove has its tip entering the inside of the notch, external force is applied when transporting or mounting electronic components in the wiring board area, etc. Even if the force concentrates on the edge of the split structure and a crack occurs in the insulating substrate starting from the edge, the progress of the crack is blocked by the frame-shaped metal layer formed around it. Can be effectively prevented. Therefore, it is possible to provide a multi-piece wiring board capable of accurately and surely mounting electronic components such as a semiconductor element and a crystal resonator in each wiring board region of the insulating board.

  In addition, since the metal layer is formed in a frame shape on the outer periphery, it suppresses deformation and the like when firing the insulating substrate or mounting electronic components, etc. Can be difficult.

  In addition, when the metal layer is formed on the main surface of the insulating substrate, the force applied when mounting electronic components on the wiring board region is absorbed and relaxed by the metal layer, which effectively breaks the insulating substrate. Can be prevented.

  In addition, when the metal layer is formed on the main surface on which the electronic component is mounted, the electronic component mounted on the wiring board region is joined by covering the electronic component with potting resin. When sealing the parts in an airtight manner, the metal layer can be used effectively for preventing the resin from flowing.

  In the multi-cavity wiring board of the present invention, preferably, the metal layer is electrically connected to the wiring conductor formed on the wiring board, and the exposed surface of the wiring conductor is coated with a plating layer by electrolytic plating. Since a conductive path is formed, it is possible to effectively use the area of the multi-layer wiring board by combining the function of protecting the insulating layer with the metal layer and the function of the conductive path for electrolytic plating. The conductive path can have a large area, and the plating layer can be satisfactorily and uniformly applied to the exposed surface of the wiring conductor in the wiring board region using the electrolytic plating method.

  Embodiments of the multi-piece wiring board of the present invention will be described in detail below. FIG. 1 is a plan view of a multi-cavity wiring board according to the present invention, and FIG. 2 is a cross-sectional view taken along line XX of the multi-cavity wiring board shown in FIG. In these drawings, 1 is an insulating substrate, 2 is a wiring board region, 3 is a margin region, and 4 is a dividing groove.

  In the multi-piece wiring board of the present invention, a plurality of wiring board regions 2 are arranged vertically and horizontally at the center of a flat insulating substrate 1 and the wiring board region is formed on at least one main surface of the insulating substrate 1. In the insulating substrate 1, a frame-like metal layer 5 is formed on the main surface or the outer periphery of the insulating substrate 1 along the entire boundary. A notch 5a is formed at a portion facing the tip of the split groove 4 at the periphery, and the tip of the split groove 4 enters the inside of the notch 5a.

  The insulating substrate 1 of the present invention is made of ceramics such as an aluminum oxide sintered body (alumina ceramics), an aluminum nitride sintered body, a mullite sintered body, and a glass ceramic, and includes a large number of small wiring boards simultaneously. Functions as a base material for intensive production.

  If such an insulating substrate 1 is made of, for example, an aluminum oxide sintered body, an appropriate organic binder and solvent are added to and mixed with raw material powders such as aluminum oxide, silicon oxide, calcium oxide, magnesium oxide, etc. This is formed into a sheet shape by employing a conventionally known doctor blade method to obtain a plurality of ceramic green sheets, and thereafter, these ceramic green sheets are appropriately punched and moved up and down. A plurality of layers are laminated, and finally, this laminated body is manufactured by firing at a temperature of about 1600 ° C. in a reducing atmosphere.

  A wiring conductor 6 is deposited on each wiring board region 2 formed in the central portion of the insulating base 1, and the wiring conductor 6 is made of tungsten (W), molybdenum (Mo), copper (Cu), silver. As an external terminal made of a metal such as (Ag) and connected to each electrode of an electronic component (not shown) mounted on the wiring board via an electrical connection means such as a solder bump or connected to an external electric circuit board Used.

  The exposed surface of the wiring conductor 6 is preferably coated with a metal having excellent corrosion resistance, such as nickel (Ni), gold (Au), or Ag, with a thickness of about 1 to 20 μm. Can be effectively prevented from being oxidized and corroded, and the connectivity between the wiring conductor 6 and the electrical connection means such as the conductive bonding material and solder can be improved. Therefore, on the exposed surface of the wiring conductor 6, for example, a Ni plating layer having a thickness of about 1 to 10 μm and an Au plating layer having a thickness of about 0.1 to 3 μm are sequentially covered by an electrolytic plating method or an electroless plating method. More preferably it is worn.

  In addition, a dividing groove 4 is formed on at least one main surface of the insulating substrate 1 so as to be divided into sections of the wiring board region 2. The dividing groove 4 is formed on a green sheet for the insulating substrate 1 on a cutter blade or a gold plate. A notch that becomes a division groove 4 having a constant width and depth is formed along the boundary of the wiring substrate region 2 by a mold or the like, and is fired at a high temperature together with the insulating substrate 1 so that it can be formed at a predetermined position. .

  In the multi-piece wiring board according to the present invention, the insulating substrate 1 is divided at the inner peripheral portion of the metal layer 5 while the frame-like metal layer 5 is formed over the entire outer periphery of the main surface or inner layer. A notch 5a is formed in a portion of the groove 4 facing the tip 4a, and the tip 4a of the dividing groove 4 enters the inside of the notch 5a. As a result, an external force is applied during transportation or when an electronic component is mounted on the wiring board region 2, and the force is concentrated on the end A of the divided structure 4 and starts from the end A. Even if a crack occurs in the insulating substrate 1, the progress of the crack can be effectively prevented by the frame-shaped metal layer 5 formed in the surrounding area as a barrier. Therefore, it is possible to provide a multi-piece wiring board capable of accurately and surely mounting electronic components such as semiconductor elements and crystal resonators on each wiring board region 2 of the insulating board 1.

  In addition, since the metal layer 5 is formed in a frame shape on the outer peripheral portion of the insulating substrate 1, when the ceramic green sheet to be the insulating substrate 1 is fired at a high temperature, electronic components or the like are placed in the wiring substrate region 2. When mounted, the insulating substrate 1 can be prevented from being greatly deformed, and the strength of the insulating substrate 1 can be made high so that it is difficult to inadvertently break.

  When the metal layer 5 is formed on the main surface of the insulating substrate 1, the force applied to the insulating substrate 1 is absorbed and relaxed by the metal layer 5 when an electronic component is mounted on the wiring substrate region 2. The cracking of the insulating substrate 1 can be effectively reduced.

  When the metal layer 5 is formed on the main surface on which the electronic component is mounted, the electronic component mounted on the wiring board region 2 is bonded so as to cover the electronic component with potting resin. Thus, when the electronic component is hermetically sealed, the metal layer 5 can be effectively used for preventing resin flow.

  Such a metal layer 5 is formed by, for example, applying a predetermined organic solvent to a metal powder such as W or Mo and a metal paste obtained by adding and mixing a solvent to a green sheet to be an insulating substrate 1 by a screen printing method in advance. By being printed and coated on the insulating substrate 1, it is formed in a frame shape at a predetermined position of the insulating substrate 1.

  Further, as shown in the plan view of the multi-piece wiring board in FIG. 3, the width of the front end portion of the notch 5a may be formed wide. As a result, even if the dividing groove 4 formed in the insulating substrate 1 is slightly inclined with respect to the predetermined position, the formation of the dividing groove 4 on the metal layer 5 is suppressed, and the notch 5a. The wide portion of the tip portion of this can be used not only for forming the dividing groove 4 but also as a recognition pattern used when mounting an electronic component.

  In the multi-piece wiring board of the present invention, preferably, the metal layer 5 is electrically connected to the wiring conductor 6 formed in the wiring board region 2 and is electroplated on the exposed surface of the wiring board region 2. It is preferable to form a conductive path for depositing the plating layer by the method. Thereby, by making the metal layer 5 have both a function of protecting the insulating substrate 1 and a function as a conductive path for electrolytic plating, a large-area conductive path is obtained by effectively using the area of the multi-piece wiring board. It is possible to apply a plating layer on the exposed surface of the wiring conductor 6 in the wiring board region 2 in a good and uniform manner using an electrolytic plating method.

  Such a metal layer 5 is electrically connected to the wiring conductor 6 in a portion where the dividing groove 4 is not formed, and a part of the metal layer 5 is led out to the main surface or the side surface of the insulating substrate 1. Has been. Then, the insulating substrate 1 is immersed in an electrolytic plating bath, and a portion led out to the main surface or side surface of the insulating substrate 1 of the metal layer 5 is connected to a plating power source, whereby the exposed surface of the wiring conductor 6 is exposed. A plating layer is applied.

  Thus, after mounting and sealing electronic components on the multi-cavity wiring board of the present invention, bending along the dividing grooves 4 makes it possible to obtain a large number of electronic devices.

  It should be noted that the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention. For example, when it is formed on the main surface of the insulating substrate 1, the metal layer 5 may be formed of a frame-shaped insulating layer. In such a case, an insulating paste made of the same material as that of the insulating substrate 1 is printed on the green sheet for the insulating substrate 1 in a predetermined pattern and fired at a high temperature together with the green sheet for the insulating substrate 1. Thus, it can be formed on the main surface of the insulating substrate 1. Further, an insulating layer having a color tone different from that of the insulating substrate 1 may be used.

It is a top view which shows an example of embodiment about the multi-piece wiring board of this invention. It is sectional drawing in the XX line of FIG. It is a top view which shows another example of embodiment about the multi-piece wiring board of this invention. It is sectional drawing of the conventional package for electronic component accommodation.

Explanation of symbols

1: Insulating substrate 2: Wiring substrate region 4: Dividing groove 5: Metal layer 6: Wiring conductor

Claims (2)

A plurality of wiring board regions are arranged vertically and horizontally in the center of the flat insulating substrate, and a dividing groove is formed along the boundary of the wiring substrate region on at least one main surface of the insulating substrate. The insulating substrate has a frame-like metal layer formed on the outer peripheral portion of the main surface or the inner layer over the entire circumference, and the dividing groove is formed on the inner peripheral portion of the metal layer. A multi-piece wiring board, wherein a notch is formed at a portion facing the front end, and the front end of the dividing groove enters the inside of the notch. The metal layer is electrically connected to a wiring conductor formed in the wiring board region and forms a conductive path for depositing a plating layer on the exposed surface of the wiring conductor by an electrolytic plating method. The multi-piece wiring board according to claim 1, wherein:

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