JP2007173630A - Multiple wiring board - Google Patents

Abstract

Provided is a multi-cavity wiring board in which the possibility of burrs and chipping is reduced when a mother board is divided along a dividing groove.
A multi-piece wiring board includes a mother board 101 in which a plurality of wiring board regions 102 are arranged vertically and horizontally, an opening 104 formed in each of the plurality of wiring board regions 102, and a bottom surface of the opening 104. A stepped portion 105 that is unevenly distributed, a dividing groove 108 formed at the boundary of the plurality of wiring board regions 102, and a recess 110 formed on the upper surface of the stepped portion 105 in parallel with the dividing groove 108. It has.
[Selection] Figure 1

Description

  The present invention relates to a multi-piece wiring board in which a plurality of wiring board regions on which electronic components such as semiconductor elements and crystal resonators are mounted are arranged in a row and in a row.

  In a conventional multi-cavity wiring board, a plurality of wiring board areas are formed on a mother board, and an opening for accommodating an electronic component is formed in each wiring board area. Dividing grooves are formed at the boundaries between the plurality of wiring board regions, and each wiring board region (wiring board) is separated into pieces by dividing the mother board along the dividing grooves.

Further, as a conventional multi-cavity wiring board, for example, a stepped portion on which electrode pads to which electronic components are electrically connected is provided on the bottom surface of openings in a plurality of wiring board regions. In some cases, the stepped portion is unevenly distributed on the bottom surface of the opening in consideration of a rational arrangement of the electronic components.
JP 2001-179731 A

  However, in the conventional multi-cavity wiring board in which the stepped portion is provided unevenly on the bottom surface of the opening, the rigidity in a plurality of areas adjacent to the dividing groove is different, and the mother board is divided along the dividing groove. There is a problem that burrs, chips, and the like are likely to occur in a portion having low rigidity due to an impact at the time of forming.

  In particular, with the recent miniaturization of electronic devices, the thickness of the frame portion located around the opening portion has been reduced, and the possibility of occurrence of burrs and chipping in this frame portion has further increased.

  The present invention has been devised in view of such conventional problems, and an object of the present invention is to reduce the possibility of occurrence of burrs and chips when the mother board is divided along the dividing grooves. It is to provide a wiring board.

  The multi-cavity wiring board of the present invention is unevenly distributed on a mother board in which a plurality of wiring board regions are arranged vertically and horizontally, an opening formed in each of the plurality of wiring board regions, and a bottom surface of the opening. A stepped portion provided, a division groove formed at a boundary between the plurality of wiring board regions, and a concave portion formed in parallel with the division groove on an upper surface of the stepped portion. Is.

  The multi-piece wiring board of the present invention is characterized in that the concave portion is arranged so as to be separated from the edge of the upper surface of the stepped portion.

  The multi-piece wiring board of the present invention is characterized in that the recess is formed deeper than the dividing groove.

  The multi-cavity wiring board according to the present invention includes a recess formed in parallel with the dividing groove on the upper surface of the stepped portion, so that the stepped portion may be unevenly distributed in each opening of the wiring substrate region. It is possible to reduce the difference in rigidity between the regions sandwiching the dividing grooves, and to reduce the occurrence of burrs and chips due to the division of the mother board.

  In the multi-cavity wiring board of the present invention, the concave portion is disposed away from the edge of the upper surface of the stepped portion, so that the ceramic green sheet that becomes the stepped portion is punched together with the opening. In this case, the stepped portion is formed in a closed state separated from the edge of the upper surface of the stepped portion, and the shape of the outer periphery of the stepped portion is firmly protected even after the recess is formed in the stepped portion. Deformation can be prevented. Therefore, when a plurality of ceramic green sheets serving as a mother substrate are stacked one above the other, deformation of the stepped portion and poor adhesion can be prevented.

  Moreover, since the multi-cavity wiring board of the present invention has the recess formed deeper than the dividing groove, the formation of the recess can more reliably reduce the rigidity of the stepped portion. In addition, when forming a dividing groove, when a cutter blade or the like is pushed in along the boundary of the wiring board region of the ceramic green sheet laminate as a mother substrate, the ceramic green sheet lamination in the wiring substrate region on both sides of the dividing groove Since the rigidity of the body is close, it is possible to prevent the cutter blade from escaping toward the frame part side of the wiring board region (the side where the stepped part is not formed in the frame part). Therefore, the dividing groove can be formed substantially vertically.

  Next, a multi-piece wiring board according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1A is a plan view showing an example of an embodiment of a multi-cavity wiring board according to the present invention, and FIG. 1B is an AA ′ line of the multi-cavity wiring board of FIG. It is principal part sectional drawing in. In the figure, 101 is a mother substrate, 102 is a wiring board region, 104 is an opening, 105 is a stepped portion, 108 is a dividing groove, and 110 is a recess. Each wiring board region 102 is formed with a wiring conductor 109 to which the electrode of the electronic component 107 is connected.

  The mother board 101, the wiring board region 102, the stepped part 105, the dividing groove 108, and the concave part 110 constitute the multi-cavity wiring board of the present invention.

  Here, the mother substrate 101 is formed by laminating ceramic layers made of a ceramic material such as an aluminum oxide sintered body, an aluminum nitride sintered body, a mullite sintered body, and glass ceramics.

  Each wiring board region 102 arranged vertically and horizontally on the mother board 101 has, for example, a rectangular shape having a side length of about 3 to 20 mm and a thickness of about 0.8 to 2 mm. A mounting portion (formed on the bottom surface of the opening 104 in FIG. 1) for housing and mounting the electronic component 107 is provided at the center of the upper surface of each wiring board region 102.

  If such a mother substrate 101 is made of, for example, an aluminum oxide sintered body, a plurality of ceramic green sheets obtained by forming a raw material powder such as aluminum oxide into a sheet shape are prepared, and the wiring substrate is partitioned vertically and horizontally. A region 102 is provided, and then a part of the ceramic green sheet is subjected to an appropriate punching process, and then laminated and fired.

  In this embodiment, the mother board 101 is a frame-like middle layer (opened) that forms an opening 104 at the center of each wiring board region 102 on a flat-plate lower layer (not labeled) ceramic green sheet. The ceramic green sheets of the unsigned and upper layers (unsigned) are sequentially laminated. The opening size of the middle layer is partially smaller than the opening size of the upper layer, and the portion having this small opening size is exposed inside the opening 104 and is unevenly distributed on the bottom surface to form a stepped portion 105.

  In order to form the opening 104, for example, the upper ceramic green sheet is punched into a square shape, and the middle ceramic green sheet that becomes the stepped portion 105 is punched so as to be unevenly distributed on the bottom surface of the opening 104. Further, after forming holes to be the concave portions 110 by punching, the upper and middle ceramic green sheets can be positioned, stacked and adhered to the ceramic green sheets to be the mounting portions of the electronic components 107. In this case, the recess 110 may be formed at a time so that the punching process can be performed simultaneously with the formation of the opening of the middle layer.

  In the mother board 101, a dividing groove 108 is formed at the boundary between the plurality of wiring board regions 102. By applying a bending stress so as to bend the mother board 101 along the dividing groove 108, the mother board 101 is broken along the dividing groove 108 and divided into individual wiring board regions 102.

  A wiring conductor 109 is formed in the wiring board region 102. The wiring conductor 109 is electrically connected to the electrode of the electronic component 107 mounted on the mounting portion via a bonding wire, solder, or the like, and functions as a conductive path leading to the lower surface or side surface of the wiring board region 102.

  The wiring conductor 109 is made of a metal material such as tungsten, molybdenum, copper, or silver. For example, if the wiring conductor 109 is made of tungsten, a metal paste of tungsten is applied to a green sheet as the mother substrate 101 in a predetermined pattern of the wiring conductor 109. It is formed by printing.

  In addition, in order to prevent oxidation corrosion on the exposed surface of the wiring conductor 109 and to improve characteristics such as solder wettability and bonding wire bonding property when connecting the solder or bonding wire, nickel, gold, etc. A plating layer (not shown) is applied.

  The stepped portion 105 has a function in which, for example, one end portion of the wiring conductor 109 is formed on the upper surface, the distance between the wiring conductor 109 and the electrode of the electronic component 107 is shortened, and the connection by the bonding wire or the like is easy and reliable. Have In this case, the stepped portion 105 is formed to have the same height as the electronic component 107.

  The multi-cavity wiring board of the present invention includes a recess 110 formed in parallel with the dividing groove 108 on the upper surface of the stepped portion 105.

  Because of such a structure, even if the stepped portion 105 formed in each opening 104 of the wiring board region 102 is unevenly distributed so as to be asymmetrical, the frame portion 106 is formed by the stepped portion 105. It is possible to reduce the increase in the rigidity by forming the recess 110. Therefore, it is possible to suppress a large difference in the rigidity of each mother wiring board region 102 (particularly, the frame portion 106) that is in contact with the dividing groove 108 therebetween.

  In other words, with such a configuration, the rigidity of the frame portion 106 can be appropriately adjusted on the upper surface of the stepped portion 105 at the boundary with the adjacent wiring board region 102 by the concave portion 110 formed in parallel with the dividing groove 108. Therefore, when the mother board 101 is divided for each wiring board area 102, the generation of burrs and chips can be prevented and each wiring board area 102 can be easily divided.

 In this case, it is preferable that the concave portion 110 is formed in a groove shape with rounded corners because punching is easy and productivity can be secured satisfactorily, and the rigidity of the frame portion 106 can be adjusted effectively.

  Further, in the multi-cavity wiring board of the present invention, it is preferable that the concave portion 110 is disposed away from the edge of the upper surface of the stepped portion 105.

  Due to such a structure, when the ceramic green sheet that becomes the stepped portion 105 is punched together with the opening 104 and the concave portion 110 is formed, the ceramic green sheet is formed in a state of being separated from the upper edge of the stepped portion 105 and closed. Thus, even after the recess 110 is formed in the stepped portion 105, the shape of the outer periphery of the stepped portion 105 is firmly protected, and deformation of the stepped portion 105 can be prevented.

  Therefore, even if the wiring conductor 109 is formed on the upper surface of the stepped portion 105 in which the concave portion 110 is formed, the stepped portion 105 is prevented from being deformed, and the positional accuracy of the wiring conductor 109 is not deteriorated. Can be easily connected to the wiring conductor 109.

Here, the distance at which the concave portion 110 is separated from the edge of the upper surface of the stepped portion 105 is the closest portion so that deformation of the stepped portion 105 does not occur when the hole to be the concave portion 110 is formed by punching. The thickness is preferably 500 μm or more (in the state of a ceramic green sheet).

  Further, in the multi-piece wiring board of the present invention, it is preferable that the recess 110 is formed deeper than the dividing groove 108.

  With such a structure, the rigidity of the stepped portion 105 can be more reliably reduced by forming the recess 110. Further, when the cutter blade or the like is pushed in along the boundary of the wiring substrate region 102 of the ceramic green sheet laminate that becomes the mother substrate 101 in order to form the dividing groove 108, the wiring substrate regions 102 on both sides of the dividing groove 108. Since the rigidity of the ceramic green sheet laminate in FIG. 6 is close, the cutter blade is prevented from escaping toward the frame part 106 side (the side where the stepped part 105 is not formed on the frame part 106) of the wiring board region 102. be able to. Therefore, the dividing groove 108 can be formed substantially vertically.

  Therefore, it is possible to prevent the dividing groove 108 from being inclined with respect to the main surface of the mother substrate 101 due to the escape of the dividing groove 108 as described above. As a result, when a bending stress is applied to the mother board 101, it is possible to cause breakage along the boundary between the wiring board regions 102 more reliably, resulting in defects such as burrs and chipping in the individual wiring boards. This can be prevented more effectively.

  The dividing groove 108 has a predetermined depth by pressing a cutter blade on the main surface of the ceramic green sheet to be the mother substrate 101 along the boundary between the wiring substrate regions 102 and the boundary between the wiring substrate region 102 and the dummy region 103. It is formed by forming a notch.

In FIG. 1B, d ₁ is the depth of the dividing groove, and d ₂ is the depth of the recess 110. Thus, by forming the dividing grooves 108 so that d ₁ <d ₂ , the rigidity as the ceramic green sheet laminate between the frame portions 106 of the adjacent wiring board regions 102 becomes close, and the cutter blade is Escape to the frame portion 106 having low rigidity can be prevented.

  It should be noted that the present invention is not limited to the above embodiments, and various modifications may be made without departing from the gist of the present invention. For example, in this example, the concave portion 110 is formed on the upper surface of the stepped portion 105 of each wiring board region 102 in parallel with the dividing groove 108, but in order to obtain the same effect at the boundary between the dummy region 103 and the wiring board region 102. In addition, it goes without saying that the recess 110 may be formed so as to have the width of the opening 104 in the dummy region 103 formed in contact with the side where the stepped portion 105 of the outermost peripheral wiring board region 102 is not formed. .

(A) is a top view which shows an example of embodiment of the multi-cavity wiring board of this invention, (b) is principal part sectional drawing in the A-A 'line of the multi-cavity wiring board of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Mother board 102 ... Wiring board area | region 104 ... Opening part 105 ... Step part 108 ... Dividing groove 110 ... Concave part

Claims (3)

A mother board in which a plurality of wiring board regions are arranged vertically and horizontally; an opening formed in each of the plurality of wiring board areas; a step-like part provided unevenly on the bottom surface of the opening; A multi-cavity wiring board, comprising: a dividing groove formed at a boundary of the wiring board region; and a recess formed in parallel with the dividing groove on an upper surface of the stepped portion. The multi-cavity wiring board according to claim 1, wherein the concave portion is arranged to be separated from an edge of the upper surface of the stepped portion. The multi-cavity wiring board according to claim 1, wherein the concave portion is formed deeper than the division groove.

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