JP6725333B2 - Multi-cavity wiring board and wiring board - Google Patents

Description

The present invention relates to a multi-cavity wiring board and a wiring board in which a plurality of wiring board regions having electronic component mounting portions are arranged vertically and horizontally on a mother board.

BACKGROUND OF THE INVENTION Conventionally, a wiring board for housing electronic components, such as a semiconductor device or a surface acoustic wave device, which is used for housing electronic components, is made of an insulating material such as an aluminum oxide sintered body or a glass ceramic sintered body. The substrate has a concave mounting portion for accommodating electronic components. The insulating substrate generally has a square flat plate-shaped base portion and a square frame-shaped frame portion stacked on the upper surface of the base portion so as to surround the mounting portion. Further, a metal frame body (also referred to as a seal ring) is joined to the upper surface of the frame portion via the frame-shaped metallized layer 116 and a brazing material. A concave mounting portion is formed by the upper surface of the base portion and the inner surface of the frame portion and the metal frame body. After the electronic component is mounted on the mounting portion, a lid made of metal is joined to the upper surface of the metal frame body to hermetically seal the mounting portion.

Such a wiring board is generally manufactured in the form of a so-called multi-cavity wiring board in which a plurality of wiring boards are simultaneously and collectively obtained from one large-area mother board. In the multi-cavity wiring substrate, a plurality of wiring substrate regions, each of which is a wiring substrate, are arranged vertically and horizontally on a mother substrate made of, for example, an aluminum oxide sintered body. Dividing grooves are formed on the main surface such as the upper surface of the mother board along the boundary of the wiring board region. A bending stress is applied to the mother board across the dividing groove to break the mother board, whereby the mother board is divided into individual wiring boards. The dividing groove is formed, for example, by making a notch at a predetermined depth on the upper surface and the lower surface of the unbaked mother board at the boundary between the adjacent wiring board regions using a cutter blade or the like.

In recent years, individual wiring boards have become smaller, and for example, those having vertical and horizontal dimensions in plan view of 1.6×1.2 mm or less are manufactured. The thickness of wiring boards has become extremely small in accordance with the miniaturization of wiring boards. Therefore, it is difficult to provide a dividing groove at the boundary between adjacent wiring board regions by using a cutter blade. Therefore, there has been proposed a method of providing a dividing groove with a laser having excellent positional accuracy (see Patent Document 1).

JP 2014-27219 JP

However, even if the positional accuracy of the dividing groove is improved by providing the dividing groove with a laser, the thickness of the dividing groove becomes extremely thin as the wiring board becomes smaller, and therefore the depth of the dividing groove cannot be set large. There is a problem that the width of the opening in the dividing groove is reduced. This is because if the depth of the dividing groove is small, the width of the opening in the dividing groove becomes smaller according to the depth of the dividing groove.

In this way, when the width of the opening in the dividing groove becomes small, when the dividing groove is provided by the laser in the ceramic green sheet laminated body which becomes the multi-cavity wiring board before firing, adjacent wiring board regions are connected during firing. Or, since the wiring conductors in the adjacent wiring board regions are connected to each other via the plating film after the plating process, the divisibility of the mother board is deteriorated, and burrs and chips are generated on the wiring board, There was a possibility that a portion different from the portion would be divided, resulting in defective cracking.

A multi-cavity wiring board according to an aspect of the present invention has a plurality of wiring board regions arranged therein, a first main surface and a second main surface opposite to the first main surface, and Surface and the second main surface having a dividing groove along the boundary of the wiring board region, one side and the other side of the second main surface of the wiring board region, and 2 main surfaces are provided with external connection conductors provided in each corner portion in contact with the one side and the other side, and the dividing groove on the second main surface is formed on the external connection conductors. The width of the first divided groove provided in the region along the first divided groove and the width of the second divided groove provided in the region sandwiched by the external connection conductors are the same as the width of the second divided groove. It is characterized in that it is provided larger than the width.

A wiring board according to one aspect of the present invention has a first main surface and a second main surface opposite to the first main surface, and has a rectangular substrate in plan view, and one side of the second main surface. And the other side, and the substrate is provided with an external connection conductor provided in each corner portion in contact with the one side and the other side, and the substrate corresponding to the region along the external connection conductor. angle between the first side and the second major surface of the substrate, the much larger than the angle between the second side surface and the second major surface of the substrate corresponding to the region between the outer connecting conductors, The length of the second side surface in the thickness direction of the substrate corresponding to the region sandwiched by the external connection conductors is the length of the first side surface in the thickness direction of the substrate corresponding to the region along the external connection conductors. and wherein the magnitude Ikoto than is.

According to the multi-cavity wiring board of one aspect of the present invention, with the above configuration , adjacent wiring board areas are connected to each other during firing, or wiring conductors of adjacent wiring board areas after the plating step interpose a plating film. Connection is suppressed. Therefore, the dividability of the mother substrate is less likely to deteriorate, and the possibility that burrs and chips are generated on the wiring substrate, or the division of the wiring substrate at a position different from the predetermined position to cause a division defect is reduced.

According to the wiring board of one aspect of the present invention, with the above configuration , it is possible to realize a wiring board having excellent external dimension accuracy. In other words, since it is difficult to provide burrs and chips around the individualized wiring board, especially in the region along the external connection conductor of the wiring board, a wiring board that has good storability when stored in a tray or the like is provided. Can be provided.

FIG. 3 is a bottom view showing a part of the multi-cavity wiring board according to the embodiment of the present invention. It is a principal part enlarged view which shows the cross section in the A-A' line of FIG. It is a principal part enlarged view which shows the cross section in the B-B' line of FIG. It is a perspective view which shows the principal part of the lower surface of the wiring board of embodiment of this invention. FIG. 6 is a cross-sectional view of a main portion showing an angle formed by the first side surface and the second main surface of the wiring board according to the embodiment of the present invention. FIG. 6 is a cross-sectional view of a main portion showing an angle formed by a second side surface and a second main surface of the wiring board according to the embodiment of the present invention.

A multi-cavity wiring board and a wiring board of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a bottom view showing a part of a multi-cavity wiring board according to an embodiment of the present invention. 2 is an enlarged view of a main part showing a cross section taken along the line A-A′ of FIG. 1, and FIG. 3 is an enlarged view of a main part showing a cross section taken along the line B-B′ of FIG. 1. FIG. 4 is a perspective view showing a main part of the lower surface of the wiring board according to the embodiment of the present invention. Further, FIG. 5 is a sectional view of an essential part showing an angle formed by the first side surface and the second main surface in the wiring board of the embodiment of the present invention, and FIG. 6 is an angle formed by the second side surface and the second main surface. FIG.

In FIGS. 1 to 6, 101 is a mother board (multi-piece wiring board), 102 is a wiring board area to be a package for storing electronic components, 103 is a dummy area, 104 is an external connection conductor, 105 is one side, 106 Is the other side, 107 is the first dividing groove, 108 is the second dividing groove, 109 is the first side surface, 110 is the second side surface, 111
Is a through hole, 112 is a first main surface, 113 is a second main surface, 114 is a dividing groove, 115 is a fracture surface, 116 is a frame-shaped metallization layer, 201 is a wiring substrate, and 202 is a notch. 1 to 6, the same parts are designated by the same reference numerals.

A wiring board 201, which is an electronic component storage package arranged on the mother board 101, has a first main surface 112 including a concave mounting portion (not shown), and an electronic component (not shown) is mounted on this mounting portion. Is housed. The wiring board 201 has a base portion and a frame portion laminated on the base portion. A frame-shaped metallized layer 116 is provided on the frame portion of the first main surface 112, and a metal frame (not shown) and a metal lid (not shown) are joined to the frame-shaped metallized layer 116 by a brazing material. .. When a metal frame is joined to the frame-shaped metallized layer 116, a metal lid is further joined to the metal frame. The wiring board 201 has wiring conductors to which electronic components are connected, external connection conductors, side surface conductors, and the like. Further, the electronic device is formed by joining the electronic component to the wiring conductor provided on the mounting portion of the wiring board 201 with a joining material or the like.

Such a wiring board 201 is generally manufactured in the form of a so-called multi-cavity wiring board, in which a plurality of wiring boards 201 are collectively obtained from one large-area mother board 101. In the multi-cavity wiring board, a plurality of wiring board regions 102 are arranged vertically and horizontally on a mother board 101 made of, for example, an aluminum oxide sintered body. As shown in FIG. 1, the mother substrate 101 has a through hole 111 on the outer periphery.
The wiring board regions 102 provided with are arranged. Further, an inner surface conductor (not shown) is provided on the inner surface of the through hole 111 in the through hole 111 provided on the outer periphery of the wiring board region 102, and the wiring conductors of the adjacent wiring board regions 102 are electrically connected to each other. Has the function of connecting to. FIG. 1 shows a structure in which the through conductors are provided at the four corners of each wiring board region 102. The through conductors may be formed at positions other than the four corners of each wiring board region 102, for example, in the central portion on the long side (one side 105) or the short side (the other side 106). .. The inner conductors provided in the through holes 111 connect the wiring conductors (not shown) between the adjacent wiring board regions 102, the external connection conductors 104, etc., and integrally connect the respective wiring conductors of the mother board 101. To be done. Then, for example, electricity is supplied from the plating conductor by being led out to the plating conductor (not shown) provided in the cutout portion of the dummy area 103 of the mother substrate 101, and is supplied to the external connection conductor 104 and the like. Electroplating is applied.

The mother substrate 101 is a ceramic sintered body such as an aluminum oxide sintered body, a glass ceramic sintered body, an aluminum nitride sintered body, a silicon carbide sintered body, a silicon nitride sintered body, or a mullite sintered body. It is formed by the body.

The mother substrate 101 is manufactured by laminating a plurality of ceramic insulating layers, and integrally firing the laminated body. That is, if the mother substrate 101 is made of an aluminum oxide sintered body, it is manufactured as follows. First, a plurality of ceramic green sheets are produced by adding a suitable organic solvent and a binder to a raw material powder containing a glass component, such as aluminum oxide and silicon oxide, and molding the mixture into a sheet shape. Next, after punching a part of this to form a sheet provided with a plurality of frame parts, a plurality of frame parts are formed on the flat ceramic green sheet which is not punched. Stack the ceramic green sheets. After that, if this laminated body is integrally fired, a mother substrate 101 in which wiring substrate regions 102 in which a plurality of ceramic insulating layers are laminated are formed vertically and horizontally can be manufactured. In this case, the punched ceramic green sheet serves as the frame portion, and the unpunched ceramic green sheet serves as the base portion.

The wiring board 201, which is a package for storing electronic components, has a mounting portion (concave portion) for the electronic components in the center of the upper surface thereof. The base portion and the frame portion act as a container for protecting the electronic components housed in the mounting portion. Electronic components housed in the mounting portion include various types of electronic devices such as a piezoelectric vibrator such as a crystal vibrator, a surface acoustic wave device, a semiconductor device such as a semiconductor integrated circuit device (IC), a capacitor device, an inductor device, and a resistor. You can list the parts.

The electronic component storing package of such a form is, for example, a case where the electronic component is a crystal oscillator, and when the electronic device is a crystal device, a communication device such as a mobile phone or a smart phone, a computer, an IC card, or the like. It is used as a package for an oscillator that serves as a frequency or time reference in electronic equipment such as information equipment. Also, the electronic device in this case is used as an oscillator. The electronic component housed in the mounting portion is electrically connected to the wiring conductor by a bonding material such as a conductive adhesive.

The wiring board 201 is manufactured by a so-called multi-cavity form and divided into individual pieces. For example, a plurality of wiring board regions 102 having mounting portions are arranged vertically and horizontally on a mother board 101 formed by laminating a plurality of ceramic insulating layers. A dividing groove 114 is formed on the upper surface of the mother substrate 101 along the boundary of the wiring substrate region 102 by a laser, and a multi-cavity wiring substrate as shown in FIG. 1 is basically constructed. The mother board 101 is divided along the boundary of the wiring board region 102, and the wiring board 201 to be an electronic component storage package is manufactured.

In order to divide the mother board 101, dividing grooves 114 are formed in the first main surface 112 and the second main surface 113 of the mother board 101 along the boundary of the wiring board region 102. As shown in FIG. 1, on the second main surface 113, the dividing groove 114 is composed of a first dividing groove 107 and a second dividing groove 108. The first dividing groove 107 is provided in a region along the external connecting conductor 104, and the second dividing groove 108 is a region sandwiched between the external connecting conductors 104, that is, an external connecting conductor in the outer periphery of the wiring board region 102. It is provided in a region where 104 is not provided. The dividing groove 114 is composed of a first dividing groove 107 and a second dividing groove 108, and is provided in a grid pattern between the wiring board regions 102 of the mother substrate 101 and between the wiring board regions 102 and the dummy regions 103. Has been. Then, stress is applied to the mother substrate 101 at the portions where the respective dividing grooves 114 are formed (boundary of the wiring substrate region 102, etc.) to bend the mother substrate 101 in the thickness direction, so that the mother substrate 101 is separated into individual pieces. The wiring board 201 will be divided.

Wiring conductors and the like are formed inside and on the surface of the wiring board 201 from the bottom of the mounting portion to the lower surface of the wiring board 201. Of these wiring conductors, the portion formed on the second main surface 113 of the wiring board 201 is, for example, the external connection conductor 104. Among the wiring conductors, those formed inside the wiring board 201 are through conductors (so-called via conductors) and wiring conductors for connecting electronic components. By electrically connecting the electronic component mounted on the mounting portion to the wiring conductor, the electronic component is electrically connected to an external electric circuit (not shown) via the wiring conductor and the external connection conductor 104. become.

These wiring conductors are made of a metal material such as copper, silver, palladium, gold, platinum, tungsten, molybdenum, manganese, or an alloy containing them. If the wiring conductor is made of, for example, molybdenum which is a refractory metal, a metal paste (not shown) prepared by adding an organic solvent and a binder to molybdenum powder is used as a ceramic green sheet for the wiring board 201. It can be formed by applying in a predetermined pattern and co-firing.

In the multi-cavity wiring board, at each corner of the lower surface of each wiring board region 102,
A metallized conductor layer that becomes the external connection conductor 104 of the wiring board 201 after division is formed. For example, the outer periphery of the external connection conductor 104 is in contact with the first division groove 107. The external connection conductor 104 is made of a metal such as tungsten or molybdenum. For example, when the external connection conductor 104 is made of a molybdenum metallized conductor layer, a metal produced by adding an organic solvent, a binder or the like to molybdenum powder. It can be formed by printing the paste in a predetermined pattern on the lower surface of the ceramic green sheet to be the ceramic insulating layer (base). The metal paste is formed by, for example, a screen printing method or the like so that the thickness of the external connection conductor 104 after firing is about 8 to 20 μm.

In addition, a metal frame (not shown) may be further joined to the upper surface of the frame-shaped metallized layer 116 on the upper surface (first main surface 112) with a brazing material. The joining of the metal frames may be performed in the state of a multi-piece wiring board or in the state of an individual electronic component storage package (wiring board 201). When productivity is taken into consideration, the above-mentioned joining is performed in a state in which many pieces are taken. Then, a metal lid is joined to the metal frame to seal the electronic component in the mounting portion. In the example of this embodiment, a plating layer (not shown) such as a nickel plating layer and a gold plating layer is sequentially deposited on the exposed surfaces of the frame-shaped metallized layer 116, the metal frame, and the external connection conductor 104. ing. Then, for example, the nickel plating layer is about 1.0 to 20 μm, and the gold plating layer is 0.1 to 1.0 μm.
It is formed in about m. Since the exposed surface of each metal layer is covered with these plating layers, corrosion prevention of the metal layer and wettability of solder, brazing material, etc. are improved.

A multi-cavity wiring board according to one aspect of the present invention has a plurality of wiring board regions 102 arranged therein, a first main surface 112, and a second main surface 113 facing the first main surface 112. Mother substrate 101 having dividing grooves 114 along the boundary of wiring board region 102 on first main surface 112 and second main surface 113, and one side 105 and the other side of second main surface 113 of wiring board region 102. And the external connection conductor 104 provided at each corner in contact with one side 105 and the other side 106 on the second main surface 113, and the dividing groove 114 on the second main surface 113. Has the width of the first dividing groove 107 provided in the region along the external connecting conductor 104 and the second dividing groove 108 provided in the region sandwiched by the external connecting conductor 104. Is larger than the width of the second dividing groove 108.

With such a structure, it is possible to prevent the adjacent wiring board regions 102 from being connected to each other during firing, or the wiring conductors of the adjacent wiring board regions 102 to be connected to each other via the plating film after the plating step. .. Therefore, the dividability of the mother substrate 101 is less likely to deteriorate, and the possibility that burrs and chips are generated in the wiring substrate 201 or that the wiring substrate 201 is divided at a place different from a predetermined place and a division defect occurs is reduced.

That is, the dividing groove 114 on the second main surface 113 is provided with the first dividing groove 107 in a region along the external connection conductor 104, and the width of the first dividing groove 107 is larger than that of the second dividing groove 108. Since the large widths of the adjacent dividing grooves 114 on the one side 105 and the other side 106 are connected to each other, the adjacent wiring board regions 102 of the mother substrate 101 can be connected to each other during firing. Suppressed. Furthermore, when depositing a plating film on an exposed wiring conductor such as the external connection conductor 104 provided on each main surface of the mother substrate 101 after firing, the external connection conductors 104 in adjacent wiring board regions 102 are plated with each other. Connection via the membrane is suppressed.

Further, in the mother board 101 reinforced by the external connection conductors 104, the first divided grooves 107 corresponding to the external connection conductors 104 are provided larger than the width of the second divided grooves 108.
It becomes easy to be divided from the first dividing groove 107 corresponding to the above, and the possibility that burrs and chips are generated on the wiring board 201 or the wiring substrate 201 is divided at a place different from a predetermined place to cause a division defect is reduced. To be done.

As described above, in order to provide the structure in which the width of the first divided groove 107 is larger than the width of the second divided groove 108, for example, a metal to be the external connection conductor 104 is provided at each corner of the wiring board region 102. A mother substrate 101 in which a layer is formed and a metal layer to be an external connection conductor 104 is continuously formed between adjacent wiring board regions 102 is prepared, and a boundary between the wiring board regions 102 on the second main surface 113 is prepared. It is possible to form the dividing groove 114 by laser processing at the boundary between the dummy area 103 and each wiring board area 102 arranged on the outermost periphery of the mother board 101.

That is, when the dividing groove 114 is formed by laser processing from one end of the mother substrate 101 to the other end (the dividing groove 114 need not be formed on the outer edge of the mother substrate 101 as shown in FIG. 1), the external connection conductor 104 is formed. The dividing groove 114 is formed by the laser applied to the area not formed (the area where the ceramic is exposed).
By the laser applied to the area where the external connection conductor 104 is formed, the width of the dividing groove 114 is formed larger than that of the area where the external connection conductor 104 is not formed. Then, the laser irradiated on the external connection conductor 104 of the mother substrate 101 is easily absorbed by the metal such as tungsten and molybdenum forming the external connection conductor 104, whereas the region where the external connection conductor 104 is not formed (ceramic is This is because the laser applied to the exposed region) does not contain a metal (excluding metal oxide) such as tungsten or molybdenum, and the laser is difficult to be absorbed.

The step of forming the dividing groove 114 by laser processing is a step of a laminated body of a plurality of ceramic sheets, that is, an unfired laminated body which becomes the mother substrate 101. By forming the dividing grooves 114 by laser processing before firing the laminated body, workability is good, and adhesion of a melt by laser processing can be suppressed.

Specifically, a UV laser, a green laser, an IR laser, or the like may be used as the type of laser. The output per unit area of the laser at the time of laser processing (the unit area of the surface of the object to be processed at the portion irradiated with the laser) is relatively small, and accordingly the amount of melt generated is small. In this case, as compared with the external connection conductor 104 (sintered metal) provided on the second main surface 113 of the mother substrate 101 after sintering, laser processing of the external connection conductor 104 containing an organic substance such as a binder before firing is performed. It is easy to remove. Further, as compared with the ceramic forming the mother substrate 101 after sintering, it is easier to remove the laminated body (which becomes the mother substrate 101) containing an organic substance such as a binder before firing by laser processing. Therefore, it is possible to form the first dividing groove 107 and the second dividing groove 108 having a good shape even with a laser having relatively small energy as described above. Although not shown, the dividing groove 114 may be formed on the upper surface (first main surface 112) at a position overlapping the dividing groove 114 on the lower surface (second main surface 113) in a plan view. As a result, the divisibility of the mother substrate 101 is further improved.

According to the method for manufacturing the divided groove 114, in each wiring board region 102 of the mother substrate 101, the first divided groove 107 provided in the region along the external connection conductor 104 and the region sandwiched by the external connection conductor 104 are formed. It is possible to manufacture a multi-cavity wiring board in which the second dividing groove 108 to be provided is formed and further the dividing groove 114 in which the width of the first dividing groove 107 is larger than the width of the second dividing groove 108 is provided. it can.

In addition, in the multi-cavity wiring board according to one aspect of the present invention, the angle θ1 formed by the first side surface 109 of the first dividing groove 107, which is the side surface of the wiring board region 102, and the second main surface 113 is the second division. Second side surface of groove 108
It is characterized in that it is larger than an angle θ2 formed by 110 and the second main surface 113. With such a structure, the dividability of the mother substrate 101 is good, and burrs and chips at the corners of the wiring substrate 201 are suppressed, and a wiring substrate 201 with high dimensional accuracy can be manufactured. Can be realized. Bending stress is applied to the mother board 101 across the dividing groove 114 and the mother board 101 is broken to be divided into individual wiring boards 201. At this time, the mother board 101 is bent by the bending stress. At the moment of division or division, the corners of adjacent wiring board regions 102 may contact each other. Although each corner of the wiring board region 102 is a portion where burrs and chips are particularly likely to occur, even in such a state, the first side surface 109 of the first dividing groove 107 and the second main surface 113 form the same. Due to the structure in which the angle θ1 is larger than the angle θ2 formed by the second side surface 110 and the second main surface 113 of the second dividing groove 108, it is possible to suppress contact between the corner portions between the adjacent wiring board regions 102. It

That is, at each corner of the second main surface 113 of the individual wiring board 201, the angle θ1 formed by the first side surface 109 and the second main surface 113 on both the one side 105 and the other side 106. However, a region larger than the angle θ2 formed by the second side surface 110 of the second dividing groove 108 and the second main surface 113 is provided. Therefore, in the second major surface 113 of each wiring board 201, the angle is larger in the regions closer to the corners of the one side 105 and the other side 106 than in the central regions of the one side 105 and the other side 106. As a result, the mother substrate 101 has a good splittability, and burrs and chips at the corners of the wiring substrate region 102 can be suppressed, and a multi-cavity wiring substrate capable of manufacturing the wiring substrate 201 with high dimensional accuracy can be realized.

For example, a tray for carrying the wiring board 201 (a carrying container having a plurality of recesses)
The storability at the time of storing in etc. becomes good. The material of the tray is a resin such as PE (polyethylene) or PP (polypropylene), which is made of a softer material than the ceramic material forming the wiring board 201.

Further, it is a multi-cavity wiring board in which a through hole 111 is formed on the outer periphery of the wiring board region 102, and a quarter arc-shaped cutout 202 is provided at each corner of the individualized wiring board 201. Therefore, the four corners of the wiring board 201 are chamfered by the notches 202. Therefore, although it was possible to store the wiring board 201 in a tray or the like for transporting it relatively easily, as described above, the first side surface 109 and the second main surface of the first dividing groove 107 are stored. The angle θ1 with 113 is the second
Since the angle θ2 formed by the second side surface 110 of the dividing groove 108 and the second main surface 113 is made larger, one side 105 and the other side of the second main surface 113 of the wiring board 201 facing the tray or the like. The area closer to each corner of 106 has a larger angle, and the storability at the time of storing in a tray or the like is further improved.

As described above, at the four corners of the wiring board region 102 that becomes the wiring board 201, the angle θ1 formed by the first side surface 109 of the first dividing groove 107 and the second main surface 113 is the second side surface 110 of the second dividing groove 108. In order to obtain a multi-cavity wiring board having a structure larger than the angle θ2 formed between the second main surface 113 and the second main surface 113, the dividing groove 114 may be formed by the laser processing as described above. Specifically, for example, when the dividing groove 114 is formed by laser processing from one end to the other end of the mother substrate 101 by laser processing as described above, the area where the external connection conductor 104 is not formed (the area where the ceramic is exposed) is irradiated. The divided groove 114 is formed by the laser thus irradiated, and the laser irradiated on the region where the external connection conductor 104 is formed further forms the divided groove 114 wider than the region where the external connection conductor 104 is not formed.

FIG. 2 shows the first dividing groove 107 formed by the laser applied to the region where the external connection conductor 104 is formed. FIG. 2 is an enlarged view of an essential part showing a cross section taken along the line AA′ of FIG. 1. Further, FIG. 3 shows the second dividing groove 108 formed by the laser applied to the region where the external connection conductor 104 is not formed (the region where the ceramic is exposed). FIG. 3 is an enlarged view of essential parts showing a cross section taken along line BB′ of FIG. 1. In FIG. 2, the first dividing groove 107 is provided in a region between the adjacent wiring board regions 102 where the external connection conductor 104 is formed. Note that the width W1 of the first divided groove 107 in FIG. 2 is the width of the main surface of the external connection conductor 104 provided on the second main surface 113, and the width W2 of the second divided groove 108 in FIG. Is the width of the second main surface 113.

The width W1 of the first dividing groove 107 is larger than the width W2 of the second dividing groove 108 because the external connection conductor 104 absorbs the laser more easily than the ceramic forming the mother substrate 101. That is, the angle θ1 formed by the first side surface 109 and the second main surface 113 is formed larger than the angle θ2 formed by the second side surface 110 and the second main surface 113 by the width of the dividing groove 114. .. As a result, at the four corners of the wiring board region 102 serving as the wiring board 201, the angle θ1 formed by the first side surface 109 of the first dividing groove 107 and the second main surface 113 is the same as the second side surface 110 of the second dividing groove 108. It is possible to efficiently manufacture a multi-cavity wiring board in which a plurality of wiring board regions 102 having a structure larger than the angle θ2 formed with the second main surface 113 is arranged.

The width W3 of the second main surface 113 provided with the first dividing groove 107 is larger than the width W2 of the second dividing groove 108. As a result, the mother board 101 reinforced with the external connection conductors 104 is more easily divided from the first dividing groove 107 corresponding to the external connection conductors 104, and burrs and chips are generated on the wiring board 201. Or, the possibility of division failure due to division at a location different from the predetermined location is further reduced.

As shown in FIG. 2, the width of the first divided groove 107 gradually decreases from the main surface of the external connection conductor 104 to the second main surface 113, and further from the second main surface 113 to the bottom of the first divided groove 107. The width is gradually decreasing. The change in the width of the first dividing groove 107 is larger in the thickness region of the external connection conductor 104 than in the wiring substrate region 102 (ceramic portion). Such a structure also results from the fact that the external connection conductor 104 made of a metal such as tungsten or molybdenum absorbs laser more easily than the ceramic forming the mother substrate 101.

Here, the laser is applied to the mother substrate 101 from the upper side to the lower side in a substantially vertical direction, and is also irradiated so that the focal point is aligned near the lowest point of the dividing groove 114. That is, the vertical cross-sectional shape of each dividing groove 114 is V-shaped or U-shaped. Therefore, as shown in FIG. 2 and FIG. 3, the division groove 114 is provided with a larger width as it is closer to the second main surface 113 (or the main surface of the external connection conductor 104). As a result, in the wiring board 201 obtained by dividing the mother board 101 into individual pieces, when the mother board 101 is housed in a tray or the like for transportation, one side 105 and the other side 106 are close to the corners. Since the angle becomes larger and the corners on the second main surface 113 of the wiring board 201 are less likely to be sharp edges, even if the tray is made of a soft material, the corners of the wiring board 201 are not It becomes difficult to hang on the inner surface of the wiring board 201, and the storability when the wiring board 201 is stored in a tray or the like for transporting the wiring board 201 is more effectively improved. Further, it is possible to suppress the generation of dust due to the corners of the second side surface 111 of the wiring substrate 201 contacting the inner surface of the tray during transportation, and a part of the tray being scraped.

The wiring board 201 according to one aspect of the present invention includes a first main surface 112 and a second main surface 112 that faces the first main surface 112.
A substrate having a main surface 113 and having a rectangular shape in plan view, one side 105 and the other side 106 of the second main surface 113, and the substrate is in contact with the one side 105 and the other side 106, respectively. The external connection conductor 104 provided at the corner is provided, and the angle θ1 formed by the first side surface 109 and the second main surface 110 of the substrate corresponding to the region along the external connection conductor 104 is set to the external connection conductor 104. It is characterized in that it is larger than the angle θ2 formed by the second main surface 113 and the second side surface 110 of the substrate corresponding to the sandwiched region.

With such a structure, it is possible to realize the wiring board 201 having excellent external dimension accuracy. That is, since it is difficult to provide burrs and chips around the individualized wiring board 201, particularly in a region along the external connection conductor 104 of the wiring board 201, the storability at the time of storing in a tray or the like is improved. The wiring board 201 can be provided. FIG. 4 shows the main part of the lower surface of the wiring board 201.

In FIG. 4, a through hole 111 is provided at each of four corners of a wiring board 201 with a cutout 202 formed in a quarter arc shape, and an inner surface conductor (not shown) is provided on an inner surface of the cutout 202. Has been. Further, the four corners of the second main surface 113 are provided with external connection conductors 104 that are in contact with the one side 105 and the other side 106 and that are connected to the inner surface conductors provided in the notches 202. The wiring board 201 is manufactured by dividing the mother board 101, and the dividing groove 114 is not actually provided. However, in conformity with the above description, the dividing groove 114 of the wiring board 201 is formed. The expression split groove 114 will be used to indicate the position.

The external connection conductor 104 is formed by printing a predetermined pattern on the upper surface of the ceramic green sheet that serves as the base, and has a structure in which it protrudes from the second main surface 113 by the printed thickness. There is. Therefore, when the dividing groove 114 is formed on the second main surface 113 by the laser, the depth of the dividing groove 114 (first dividing groove 107) is reduced by the printed thickness as shown in FIG. There is. On the other hand, in the region where the external connection conductor 104 is not provided on the second main surface 113, when the split groove 114 (second split groove 108) is formed on the second main surface 113 by the laser,
The depth is increasing.

That is, the depth of the division groove 114 (first division groove 107) including the external connection conductor 104 provided on the second main surface 113 and the division groove 114 (second division) in the area where the external connection conductor 104 is not provided. The grooves 108) have almost the same depth, and the boundary line between the fracture surface 115 and the dividing groove 114 provided between the first main surface 112 and the second main surface 113 in the thickness direction of the wiring substrate 201 is the wiring. There is a region that bends from the four corners of the substrate 201 to the center of each side. The curved region includes a first side surface 109 provided by the first dividing groove 107 in a region where the external connection conductor 104 is provided and a region where the external connection conductor 104 is not provided (sandwiched between the external connection conductor 104). It exists between the second side surface 110 provided by the second dividing groove 108 and is provided at a total of eight locations on one side 105 and the other side 106 at each of the four corners on the second main surface 113 side of the wiring board 201. There is. Then, in the depth direction of the dividing groove 114, it gradually changes between the first side surface 109 and the second side surface 110. As a result, the angle θ1 between the first side surface 109 and the second main surface 110 of the substrate corresponding to the region along the external connection conductor 104 is the second side face of the substrate corresponding to the region sandwiched between the external connection conductors 104. Even if the structure is larger than the angle θ2 formed by 110 and the second main surface 113, it is difficult to form a step between the first side surface 109 and the second side surface 110. It should be noted that the division groove 114 may be provided on the first main surface 112 side so as to face the division groove 114 provided on the second main surface 113 in a plan view. In addition, FIG. 4 shows a main part of a wiring board 201 manufactured by dividing a mother board 101 in which dividing grooves 114 are provided on both surfaces of a first main surface 112 and a second main surface 113.
It is the perspective view seen from the 2nd main surface 113 side (lower surface side). In this way, by providing the dividing grooves 114 on both the first main surface 112 and the second main surface 113, the division provided on both the first main surface 112 and the second main surface 113 with respect to the thickness of the mother substrate 101. Since the ratio of the total depth of the grooves 114 is large, the divisibility of the mother substrate 101 is further improved.

Further, on the first main surface 112 side, although not shown, a concave mounting portion on which an electronic component is mounted is provided, and a frame-shaped metallized layer 116 is provided so as to surround the mounting portion.

FIG. 5 is a cross-sectional view showing an angle θ1 formed by the first side surface 109 and the second main surface 113 of the wiring board 201 according to the embodiment of the present invention as a main part. FIG. 6 is a cross-sectional view showing an angle θ2 formed by the second side surface 110 and the second main surface 113 of the wiring board 201 according to the embodiment of the present invention as a main part. Comparing FIG. 5 and FIG. 6, the first side surface 109 of the wiring board 201 corresponding to the region along the external connection conductor 104.
It is understood that the angle θ1 formed between the second main surface 110 and the second main surface 110 is larger than the angle θ2 formed between the second side surface 110 and the second main surface 113 of the wiring board 201 corresponding to the region sandwiched by the external connection conductors 104. .. This is because the width of the first dividing groove 107 is larger than the width of the second dividing groove 108 in the mother board 101 for manufacturing the wiring board 201.

That is, since the width of the first dividing groove 107 is large, the first side surface 109 and the second main surface 110 are provided in the region where the external connection conductor 104 of the wiring board 201 obtained by dividing the mother board 101 into pieces is provided. Since the angle θ1 formed by and the second division groove 108 is small, the second side surface 110 and the second main surface 113 are formed in the region of the wiring board 201 where the external connection conductor 104 is not provided. This is because the angle θ2 formed by and becomes small. Note that, as shown in FIG. 5, the width of the first dividing groove 107 is further increased in the thickness region of the external connection conductor 104 by the first dividing groove 107.

As a result, in the wiring board 201 of the present invention, when stored in a tray or the like for transportation, a larger angle is provided in a region closer to each corner of the one side 105 and the other side 106. As shown in FIG. 4, since it is difficult for the area along the external connection conductor 104 on the second main surface 113 of the wiring board 201 to be a sharp end, even if the tray is made of a soft material, the wiring board 201 is It becomes difficult to hang on the inner surface of the tray and the like, and the storability at the time of storing the wiring board 201 in the tray or the like for transporting becomes better and more effective. Further, it is possible to suppress the generation of dust due to the corner portions of the wiring substrate 201 on the second side surface 110 side contacting the inner surface of the tray during transportation, and a part of the tray being scraped.

The multi-cavity wiring board and the wiring board of the present invention are not limited to the examples of the above embodiment, and various modifications may be made without departing from the scope of the present invention. For example, in the example of the above-described embodiment, the mother board 101 is the wiring board 201 in which concave mounting portions are provided by a plurality of insulating layers is arranged, but a flat wiring board (not shown) having no concave portion is provided. ) May be arranged as a mother substrate. Further, although the through holes 111 provided in the squares of the wiring substrate 201 arranged on the mother substrate 101 are circular in shape, they may be elliptical or elongated holes, and in this case, the notches at the four corners of the wiring substrate are formed. The shape may be an elliptical shape or a long hole shape divided into four.

101... Mother board
102: Wiring board area
103...Dummy area
104...External connection conductor
105...One side
106...other side
107... 1st dividing groove
108: second split groove
109... First side
110...second side
111... Through hole
112...First main surface
113...second main surface
114... Dividing groove
115... fracture surface
201...wiring board
202... Notch W1... Width W1 of first split groove... Width θ2 of second split groove... Angle θ2 formed between first side surface and second main surface... Second side surface Angle formed with the second main surface

Claims (3)

A plurality of wiring board regions are arranged and has a first main surface and a second main surface opposite to the first main surface, and a boundary between the wiring board areas in the first main surface and the second main surface. A mother substrate having a dividing groove along,
One side and the other side of the second main surface of the wiring board region;
The second main surface is provided with an external connection conductor provided at each corner in contact with the one side and the other side,
The division groove on the second main surface has a width of the first division groove provided in a region along the external connection conductor and a second division groove provided in a region sandwiched by the external connection conductor. And a width of the first divided groove is larger than a width of the second divided groove. An angle formed by the first side surface of the first dividing groove, which is a side surface of the wiring board region, and the second main surface is larger than an angle formed by the second side surface of the second dividing groove and the second main surface. The multi-cavity wiring board according to claim 1, which is large. A substrate having a first main surface and a second main surface facing the first main surface and having a rectangular shape in plan view;
One side and the other side of the second main surface,
The substrate includes an external connection conductor provided in each corner portion in contact with the one side and the other side,
The angle between the first main surface and the second main surface of the substrate corresponding to the area along the external connection conductor and the second side surface of the substrate corresponding to the area sandwiched between the external connection conductors and the second main surface. much larger than the angle between second major surface,
The length of the second side surface in the thickness direction of the substrate corresponding to the region sandwiched by the external connection conductors is the length of the first side surface in the thickness direction of the substrate corresponding to the region along the external connection conductors. wiring board, wherein the size Ikoto than is.