JP2014027219A - Multi-piece wiring board, wiring board and multi-piece wiring board manufacturing method - Google Patents

Abstract

The present invention provides a multi-piece wiring board in which the rising of a melt on the upper surface of a frame portion during laser processing is suppressed.
A plurality of wiring board regions are arranged vertically and horizontally on a mother board 101 in which a ceramic insulating layer 103 containing a glass component is laminated, and along the boundary of the wiring board area 102 on the upper surface of the mother board 101. A multi-layer wiring board in which a dividing groove 105 is formed, and a metal layer 106 is formed on the upper surface of the mother substrate 101, and the dividing groove 105 extends from the upper surface of the metal layer 106 in the thickness direction of the metal layer 106. The first dividing groove 107 provided partway through the first dividing groove 107 is narrower than the bottom of the first dividing groove 107, and the second dividing groove 107 is provided on the upper surface of the mother substrate 101 through the metal layer 106 from the bottom in the thickness direction. This is a multi-cavity wiring board made up of divided grooves. Since the deep second divided groove is provided at the bottom of the shallow first divided groove 107, the rising of the melt to the upper surface of the frame portion can be suppressed.
[Selection] Figure 1

Description

  The present invention relates to a multi-cavity wiring board in which a plurality of wiring board regions having electronic component mounting portions are arranged vertically and horizontally on a mother board, a wiring board manufactured from the multi-cavity wiring board, and a multi-cavity wiring The present invention relates to a method for manufacturing a substrate.

  Conventionally, wiring boards used for mounting electronic components such as semiconductor elements and surface acoustic wave elements are electronic components on insulating substrates made of ceramic sintered bodies such as aluminum oxide sintered bodies and glass ceramic sintered bodies. It has a mounting part for mounting. The insulating substrate is generally composed of a square flat plate-like base portion and a square frame-like frame portion laminated on the upper surface of the base portion so as to surround the mounting portion. A lid is joined to the upper surface of the frame portion, and the mounting portion (electronic component mounted on the mounting portion) is hermetically sealed.

  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 obtained simultaneously from a single large-area mother board. In the multi-cavity wiring board, a plurality of wiring board regions are arranged vertically and horizontally on a mother board made of, for example, an aluminum oxide sintered body. A dividing groove is formed in 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, and the mother board is broken, so that it is divided into individual wiring boards. The dividing grooves are formed, for example, by cutting a predetermined depth on the upper and lower surfaces of an unfired mother board using a cutter blade at the boundary between adjacent wiring board regions (see Patent Document 1).

  In recent years, wiring boards have become small, and for example, a board having a size of 1.6 × 1.2 mm in length and width is manufactured. In accordance with the miniaturization of the wiring board, the wiring board area in the multi-piece wiring board has also been reduced. In such a multi-piece wiring board in which wiring board regions that are remarkably miniaturized are arranged, it is difficult to provide a dividing groove using a cutter blade at the boundary between adjacent wiring board regions in an unfired state. In view of this, a method has been proposed in which dividing grooves are formed by laser processing at the boundary between adjacent wiring board regions in the fired mother board (see Patent Document 2).

Japanese Patent Laid-Open No. 2002-11718 JP2008-192922

  However, there is a possibility that the following problems may occur with respect to the multi-piece wiring board having the division grooves provided by laser processing. That is, a part of the metal layer and the mother substrate (ceramic sintered body) provided on the upper surface of the mother substrate is melted by the laser. This melt rises from the inside of the dividing groove to the upper surface of the mother substrate (frame portion). This rising melt may make it difficult to bond the lid to the upper surface of the frame.

  The present invention has been completed in view of such conventional problems, and the object thereof is a multi-cavity wiring board having divided grooves in which the rise of the melt to the upper surface of the frame portion is suppressed, An object of the present invention is to provide a method of manufacturing a wiring board and a multi-piece wiring board.

  The multi-cavity wiring board according to one aspect of the present invention is a multi-cavity wiring board in which a dividing groove is formed along the boundary of the wiring board region on the upper surface of the mother board, and the uppermost ceramic layer A metal layer is formed on the upper surface of the insulating layer, and the dividing groove is formed by a first dividing groove provided from an upper surface of the metal layer to a middle in a thickness direction of the metal layer, and a bottom portion of the first dividing groove. And a second dividing groove provided on the upper surface of the mother board through the metal layer in the thickness direction from the bottom.

  A wiring board according to one aspect of the present invention is characterized in that the multi-piece wiring board having the above-described configuration is divided into wiring board regions.

  According to one aspect of the present invention, there is provided a method of manufacturing a multi-cavity wiring board, including a step of manufacturing a mother board in which a plurality of ceramic insulating layers including a glass component are laminated, and a plurality of wiring board regions on the mother board. And the step of irradiating the first laser beam at the boundary of the wiring board region with a shift of the focal point to form a first divided groove, along the widthwise center of the bottom of the first divided groove , Irradiating a second laser beam in focus to form a second divided groove that is narrower than the bottom of the first divided groove, and on the surfaces of the first divided groove and the second divided groove And a step of forming a protective layer containing the glass component.

  According to the multi-cavity wiring board of one aspect of the present invention, it is possible to provide a multi-cavity wiring board in which the rising of the melt from the dividing groove to the upper surface of the frame portion is suppressed.

  That is, since the first dividing groove close to the upper surface of the frame portion has a relatively shallow depth and is halfway in the thickness direction of the metal layer, it can be provided with a laser having a relatively small output per unit area. Therefore, the amount of melt generated per unit area is small, and there is little possibility that this melt will rise on the upper surface of the frame portion. In addition, the melt generated when the second divided groove is provided can remain in the first divided groove that is wider than the second divided groove. Therefore, it is possible to provide a multi-piece wiring board in which the rising of the melt on the upper surface of the frame portion is suppressed.

  According to the wiring board of one aspect of the present invention, since the multi-piece wiring board having the above configuration is divided for each wiring board region, the wiring in which the rise of the melt to the upper surface of the frame portion is suppressed. A substrate can be provided.

  According to the method of manufacturing a multi-cavity wiring board of one aspect of the present invention, since each of the above steps is included, it is possible to provide the dividing groove while suppressing the rising of the melt to the upper surface of the frame portion. A method for manufacturing a multi-piece wiring board can be provided.

  That is, first, since the laser beam is out of focus with respect to the part to be processed in the first divided groove, energy applied to the part to be processed is dispersed in a relatively wide range. Therefore, it is possible to provide the first divided groove having a relatively wide width and a relatively shallow depth while suppressing generation of a melt. Further, the second divided groove has a narrow focus and a deeper depth than the first divided groove because the laser has a focus on the part to be processed and the output per unit area is large. Can be provided. Most of the melt produced when the second divided grooves are formed solidifies into a thin film or the like inside the first divided grooves. Therefore, it is possible to provide the dividing grooves while suppressing the rising of the melt to the upper surface of the frame portion.

(A) is a top view which shows the multi-piece wiring board of embodiment of this invention, (b) is sectional drawing in the A-A 'line of (a). It is sectional drawing which shows the wiring board of embodiment of this invention. (A) And (b) is sectional drawing which shows the principal part in the manufacturing method of the multi-cavity wiring board of embodiment of this invention, respectively in order of a process. (A) And (b) is sectional drawing which shows the principal part in the manufacturing method of the multi-cavity wiring board of embodiment of this invention, respectively in order of a process. (A) And (b) is a top view which shows the principal part in the manufacturing method of the multi-cavity wiring board of embodiment of this invention, respectively in order of a process.

  A multi-cavity wiring board, a wiring board, and a manufacturing method of the multi-cavity wiring board of the present invention will be described with reference to the accompanying drawings.

  FIG. 1A is a top view showing a multi-piece wiring board according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along the line A-A ′ of FIG. FIG. 2 is a cross-sectional view showing a wiring board obtained from the multi-cavity wiring board shown in FIG. 3 (a), 3 (b) and FIGS. 4 (a), 4 (b), and 5 (a), 5 (b) are respectively important points in the method of manufacturing the multi-cavity wiring board shown in FIG. It is sectional drawing which shows a part typically in order of a process.

1 to 5, 101 is a mother board, 102 is a wiring board area, 103 is a ceramic insulating layer, 104 is a boundary of the wiring board area, 105 is a dividing groove, 106 is a metal layer, 107 is a first dividing groove, 108 Is a second dividing groove, 109 is a protective layer, 110 is a brazing material, 111 is a lid, 112 is a mounting portion, 113 is a wiring conductor, 114 is a margin area, 115 is a terminal for plating, and 116 is irradiated for the first time. , 117 is a laser irradiated for the second time, 118 is a nickel plating layer, 119 is a gold plating layer, 120 is a melt, and 121 is an electronic component housed in the mounting portion 112.

A plurality of wiring board regions 102 having mounting portions 112 are arranged vertically and horizontally on a mother board 101 in which a plurality of ceramic insulating layers 103 are laminated. On the upper surface of the mother board 101, the wiring board area 102
Divided grooves 105 are formed along the boundary 104, and a multi-piece wiring board is basically configured. The mother board 101 of such a multi-piece wiring board is divided along the boundary 104 of the wiring board region 102, and for example, a piece of wiring board as shown in FIG. 2 is produced. The wiring board to be manufactured is the above-described metal layer 106 and wiring conductor on an insulating board (no sign) in which a frame-like upper board (no sign) is laminated on the upper surface of a rectangular flat plate-like lower board (no sign). 113 etc. are provided and are fundamentally comprised.

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.

In the example of this embodiment, as shown in FIG. 1, a margin area 114 is provided on the outer periphery of the mother board 101 which is a multi-piece wiring board so as to surround the plurality of wiring board areas 102 arranged. It has been. The disposal allowance area 114 is provided for facilitating handling of the multi-piece wiring board.

The mother board 101 is manufactured by integrally firing a plurality of ceramic insulating layers 103. That is, a plurality of ceramic green sheets are produced by adding a suitable organic solvent and binder to a raw material powder containing glass components such as aluminum oxide and silicon oxide to form a plurality of ceramic green sheets. And then forming a frame shape, laminating a frame-shaped ceramic green sheet on a flat ceramic green sheet that has not been punched, and firing this laminate integrally, a plurality of ceramic insulating layers 103 Can be manufactured. In this case, if a ceramic green sheet of a plurality of ceramic green sheets is punched to provide an opening, and the ceramic green sheet having the opening is stacked on the upper layer, the mother having a recess on the upper surface is provided. The substrate 101 can be manufactured.

The plurality of wiring board regions 102 arranged on the mother board 101 have a mounting portion 112 for the electronic component 121 at the center or the like, and each is a region that becomes an individual wiring board. Each wiring board region 102 has a form in which a frame-shaped ceramic insulating layer 103 is laminated on an upper surface of a plate-shaped ceramic insulating layer 103. The frame-shaped insulating layer (hereinafter also referred to as a frame portion) is for protecting the electronic component 121 mounted on the mounting portion 112.

  Examples of the electronic component 121 mounted on the mounting unit 112 include various types of elements such as a piezoelectric vibrator such as a crystal vibrator, a surface acoustic wave element, a semiconductor element such as a semiconductor integrated circuit element (IC), a capacitive element, an inductor element, and a resistor. Can be mentioned.

A wiring conductor 113 is formed on the inside and the surface of the mother board 101 from the mounting portion 112 to the lower surface of the mother board 101. A portion of the wiring conductor 113 formed on the lower surface of the mother substrate 101 is located, for example, on the outer peripheral portion of the lower surface of each wiring substrate region 102. Among the wiring conductors 113, those formed inside the mother board 101 are in the form of a through conductor (so-called via conductor or the like), an internal wiring layer, or the like. By electrically connecting the electronic component 121 mounted on the mounting portion 112 to the wiring conductor 113, the electronic component 121 is electrically connected to an external electric circuit via the wiring conductor 113.

The wiring conductor 113 is made of, for example, copper, silver, palladium, gold, platinum, tungsten, molybdenum,
Made of a metal material such as manganese. If the wiring conductor 113 is made of, for example, molybdenum, a metal paste (not shown) prepared by adding an organic solvent and a binder to molybdenum powder is applied in a predetermined pattern to a ceramic green sheet serving as the base substrate 101. In addition, it can be formed by simultaneous firing.

  A wiring board produced by dividing a multi-piece wiring board in such a form into pieces, for example, in electronic devices such as communication devices such as mobile phones and automobile phones, information devices such as computers and IC cards, It is used as an oscillator that is a reference for frequency and time.

  In order to divide the mother board 101, dividing grooves 105 are formed on the upper and lower surfaces of the mother board 101 along the boundary 104 of the wiring board region 102. The mother board 101 is divided into individual wiring boards by applying stress to the mother board 101 at the portion where the dividing groove 105 is formed (the boundary 104 of the wiring board region 102) and breaking the mother board 101 in the thickness direction. Will be.

A metal layer 106 is formed on the upper surface of each wiring board region 102 in contact with the dividing groove 105. A lid 111 is bonded to the metal layer 106 as will be described later, and the mounting portion 112 is sealed. In the example of this embodiment, a metal layer 106 is formed by sequentially depositing a nickel plating layer 118 and a gold plating layer 119 on the upper surface of the metal layer 106.

The metal layer 106 is made of a metal such as tungsten or molybdenum. For example, if the metal layer 106 is made of a metallized layer of molybdenum, a ceramic green sheet that becomes a ceramic insulating layer 103 (the frame portion) is obtained by adding a metal paste prepared by adding an organic solvent, a binder, or the like to molybdenum powder. It can be formed by printing a predetermined pattern on the upper surface of the substrate. The metal paste is formed, for example, so that the thickness of the fired metal layer 106 is about 8 to 20 μm.

The plated layers 118 and 119 made of nickel or the like covering the metal layer 106 are formed to prevent oxidative corrosion of the metal layer 106, and to improve wettability during brazing and strengthen bonding strength. is there. For example, the plating layer preferably has a two-layer structure in which a nickel plating layer 118 is formed on the lower side and a gold plating layer 119 is formed on the upper side. Here, it is preferable that the metal plating film is thinly formed from the viewpoint of cost. The nickel plating layer 118 is formed to about 2 to 10 μm, and the gold plating layer 119 is formed to about 0.1 to 1.0 μm. These metal plating films can be formed, for example, by supplying a plating deposition current to a portion to be plated (the surface of the metal layer 106) in a plating solution and performing electrolytic plating. In addition, in order to form the protective layer 109 described above, the total thickness of the metal layer 106 and the metal plating film is about 20 to 30 μm.

The dividing groove 105 is narrower than the bottom of the first dividing groove 107 provided from the top surface of the metal layer 106 to the middle of the metal layer 106 in the thickness direction, and the thickness of the metal layer 106 from the bottom. The second dividing groove 108 is provided in the upper surface of the metal layer 106 of the mother substrate 101 so as to penetrate in the direction. Further, the inner surfaces of the first divided groove 107 and the second divided groove 108 are covered with a protective layer 109 containing a glass component. By adopting such a structure, it is possible to provide a multi-piece wiring board in which the rising of the melt 120 from the dividing groove 105 to the upper surface of the frame portion is suppressed.

That is, since the first dividing groove 107 close to the upper surface of the frame portion has a relatively shallow depth and is halfway in the thickness direction of the metal layer 106, the laser unit area during laser processing (laser irradiation) The output per unit area of the surface of the workpiece at the portion to be processed is relatively small, and the amount of the melt 120 generated is small accordingly. In this case, the metal layer 106 is easier to remove with a laser than the mother substrate 101 made of an aluminum oxide sintered body or the like. Therefore, as described above, the first division groove 107 is provided with a laser having a relatively small energy. Therefore, there is little possibility that the melt 120 generated when the first dividing groove 107 is provided rises to the upper surface of the frame portion.

  In this case, the metal component forming the metal layer 106 has a lower melting point than the mother substrate 101 and is easily removed by a laser. As described above, since the first dividing groove 106 is halfway in the thickness direction of the metal layer 106, the rising of the melt onto the frame portion is suppressed.

Further, since the second divided groove 108 is deep enough to break the mother substrate 101, the mother substrate 101 can be easily broken at the portion where the divided groove 105 is provided. That is, the mother substrate 101 can be easily divided. In addition, the melt 120 generated when the second dividing groove 108 is provided is solidified in a thin film inside the second dividing groove 108, and the first dividing groove 107 having a width wider than the second dividing groove 108 at the bottom. Most of them will stay inside. Therefore, it is possible to provide a multi-piece wiring board in which the rising of the melt 120 on the upper surface of the frame portion is suppressed.

Since the thickness of the metal layer 106 is, for example, about 10 to 30 μm, the depth of the first dividing groove 107 provided halfway in the thickness direction of the metal layer 106 is also shallow, for example, about 5 to 20 μm. ing. Since this is a shallow groove and the metal layer 106 can be removed relatively easily by a laser, the energy of the irradiated laser is relatively small and the amount of melt per unit area is also small.

Each wiring board region 102 has a quadrangular shape with a side length of, for example, about 1.0 to 3.2 mm. The outer periphery of each wiring board region 102 corresponds to the boundary 104 of the wiring board region. A dividing groove 105 is formed at a boundary 104 of the plurality of wiring board regions 102 on the upper surface of the mother board 101.

The melt 120 includes a glass component included in the ceramic insulating layer 103. The solidified product obtained by solidifying the melt 120 contains a glass component. The solidified product containing this glass component is
The mother board 101 is protected from mechanical impacts or the like by covering the inner surfaces of the first divided groove 107 and the second divided groove 108. That is, the inner surfaces of the first divided groove 107 and the second divided groove 108 are covered with the protective layer 109 containing a glass component.

In order to obtain a structure in which the inner surfaces of the first divided groove 107 and the second divided groove 108 are covered with a protective layer 109, for example, a fundamental wave laser excited by a solid laser (for example, YAG laser) is covered with a plating layer. A method of forming a V-shaped dividing groove 105 at the boundary 104 by irradiating from above the formed metal layer 106 may be mentioned. Specifically, a plurality of ceramic insulating layers 103 containing a glass component
A plurality of wiring board regions 102 are arranged vertically and horizontally on the mother board 101, and the first laser is irradiated to the boundary 104 of the wiring board region 102 while shifting the focus. Then, the first divided groove 107 is formed, and then, a second laser is irradiated along the center in the width direction of the bottom of the first divided groove 107 so as to focus from the bottom of the first divided groove 107. Narrow second
The dividing groove 108 may be formed. Through these steps, a protective layer 109 containing a glass component is formed on the surfaces of the first dividing groove 107 and the second dividing groove 108. In addition, it is possible to provide a multi-piece wiring board in which the oxidative corrosion of the metal layer 106 exposed in the dividing groove 105 is suppressed.

The mother substrate 101 is formed of a ceramic sintered body mainly composed of alumina, silicon nitride, aluminum nitride, silicon carbide, mullite, ferrite, glass ceramics or the like as described above. With such a material, a plurality of ceramic insulating layers 103 having a thickness of, for example, about 50 to 200 μm are stacked, and formed to have a thickness of, for example, 150 to 500 μm. The mother substrate 101 contains at least one metal oxide selected from the group consisting of Mg, Mn, Co, Cr, Cu, Ni and Fe as a component for increasing the laser absorption rate. It is preferable.

For example, when the mother substrate 101 is formed of a ceramic sintered body containing alumina as a main component, it includes 92% by mass of Al ₂ O ₃ as a main component, and further 3 mass of SiO ₂ as a sintering aid component. %, Mn ₂ O ₃ 3.5% by mass, MgO 1% by mass and MoO ₃ 0.5% by mass, respectively. Further, it contains 90.5% by mass of Al ₂ O ₃ as a main component, and further contains 1.5% by mass of SiO ₂ , 2.5% by mass of Mn ₂ O ₃ , 1% by mass of MgO and 1% by mass of TiO ₂ as sintering aid components. % And 3.5% by mass of CrO, respectively. Further, it contains 93% by mass of Al ₂ O ₃ as a main component, and contains 2% by mass of SiO ₂ , ₃ % by mass of Mn ₂ O ₃ , 1% by mass of MgO and MoO ₃ as a sintering aid component. 1% by mass, and those containing each.

  In the example shown in FIG. 1B, the protective layer 109 is formed so that the thickness decreases from the bottom of the second divided groove 108 to the upper end of the first divided groove 107. A lid 111 is bonded to the metal layer 106 exposed on the upper surface of the mother substrate 101 via a brazing material 110.

In the case of such a protective layer 109, the protective layer 109 is relatively thin at the upper end portion of the dividing groove 105, and the amount of the melt 120 that becomes the protective layer 109 is also relatively small. Therefore, the melt 120 on the upper surface of the frame
Thus, it is possible to provide a multi-piece wiring board in which the rising of the substrate is more reliably suppressed. Accordingly, the flatness of the upper surface of the frame portion can be secured higher. Therefore, for example, the lid body 111 can be better bonded to the metal layer 106 on the upper surface of the frame portion. In addition, it is possible to provide a multi-piece wiring board capable of manufacturing an electronic device having further excellent hermetic sealing reliability. In FIGS. 1A and 1B, the nickel plating layer 118 and the gold plating layer 119 deposited on the upper surface of the metal layer 106 are omitted.

Further, when the inner surfaces of the first divided groove 107 and the second divided groove 108 are covered with a protective layer 109 containing a glass component, the end of the metal layer 106 that contacts the divided groove 105 is exposed to the outside air. Is suppressed. Therefore, corrosion of the metal layer 106 is suppressed. Thereby, for example, the flatness on the upper surface of the metal layer 106 is maintained, and the wettability of the brazing material 110 when the lid 111 is joined to the upper surface of the metal layer 106 is also excellent.

In order to form the protective layer 109 so that the thickness decreases from the bottom of the second divided groove 108 to the upper end of the first divided groove 107, for example, the above-described laser is applied to the metal layer 106 covered with a plating layer. Irradiated from above, the first divided groove 107 in a U-shape (→ I tried to make the shape characteristics of the first divided groove and the second divided groove different) to the middle of the metal layer 106 at the boundary 104 part. And a V-shaped second divided groove 108 may be formed by penetrating the metal layer 106 in the thickness direction, which is narrower than the first divided groove 107.

Here, in the step of forming the first divided groove 107, the nickel plating layer 118 and the gold plating layer 119 do not contain a glass component, and the metal layer 106 has a glass in the vicinity of the region in contact with the ceramic insulating layer 103. Contains ingredients. For this reason, the metal layer 106, the nickel plating layer 118, and the gold plating layer 119 are formed thinly with the melt 120 containing the glass component (which becomes the protective layer 109). Further, in the step of forming the second dividing groove 108, the laser penetrates the metal layer 106 in the thickness direction, so that the melt 120 containing the glass component contained in the ceramic insulating layer 103 (becomes the protective layer 109). Are caused by the heat of the laser. The melt 120 adheres from the bottom of the second divided groove 108 to the upper end of the first divided groove 107 so that the thickness decreases, and the protective layer 109 is formed. At this time, the second dividing groove 108 is formed narrower than the first dividing groove 107, and a part of the bottom of the first dividing groove 107 in the width direction is an opening portion of the second dividing groove 108. Therefore, the distance from the opening portion of the second dividing groove 108 to the opening portion of the first dividing groove 107 is long. Therefore, the melt 120 generated in the second divided groove 108 when the second divided groove 108 is formed reaches the maximum from the opening portion of the first divided groove 107 to the first divided groove 107 (the upper end portion of the divided groove 105). It is difficult to climb up to the upper surface of the upper gold plating layer 119.

As described above, since the protective layer 109 (melt 120) is prevented from rising up to the upper surface of the uppermost gold plating layer 119, the lid 111 is formed with a sealing surface (gold plating) that ensures flatness. It can be satisfactorily bonded to the upper surface of the layer 119. A mounting portion 112 is formed inside the metal layer 106 in each wiring board region 102 of the multi-cavity wiring substrate, and an electronic component 121 is accommodated in the mounting portion 112 of each wiring substrate region 102. . Since the lid 111 can be satisfactorily bonded to the upper surface of the gold plating layer 119 surrounding the mounting portion 112 via the brazing material 110, a large number of highly reliable hermetic seals for the electronic components 121 in the respective wiring board regions 102 A single electronic device can be manufactured.

In this embodiment, the dividing groove 105 is formed only on the upper surface of the mother substrate 101, that is, one surface (upper surface) on which the metal layer 106 is formed. The division grooves 105 may be formed on both main surfaces (upper and lower surfaces) of the mother substrate 101. When the dividing grooves 105 are formed on both main surfaces, for example, a lower metal layer (not shown) which is a mounting surface on an external electric circuit board does not require high-precision flatness, so Deep division grooves (not shown) that are formed only up to the ceramic insulating layer 103 with a laser alone,
It may be formed so as to face the upper dividing groove 105 in a sectional view.

When dividing grooves (not shown) are formed on the upper and lower surfaces of the mother substrate 101, the lower dividing grooves may be deeper than the upper dividing grooves 105. In this case, for example, the dividing groove may be formed from the lower surface of the mother substrate 101 beyond the boundary between the lower substrate and the upper substrate. Thereby, the division property of the mother substrate 101 can be improved. Also in this case, it is possible to obtain a multi-piece wiring board in which the rising of the melt 120 by the laser onto the surface of the gold plating layer 119 is suppressed.

A wiring board according to an embodiment of the present invention will be described. In the wiring board of this embodiment, for example, the multi-piece wiring board is divided into a plurality of wiring board regions 102 along the dividing grooves 105. Therefore, a wiring board capable of manufacturing an electronic device excellent in hermetic sealing reliability, in which the inner surfaces of the first divided groove 107 and the second divided groove 108 are covered with a protective layer 109 containing a glass component, is provided. Can be provided.

Usually, the size of the mother substrate 101 is a flat plate having a side of about 60 to 120 mm, and the width of the discard margin region 114 formed on the outer periphery of the mother substrate 101 is about 5 to 10 mm. As a method of dividing each wiring board region 102 of the mother board 101, which is a multi-piece wiring board, into individual pieces, for example, it is sandwiched between a transfer roller and a pressing roller from above and below, and the transfer roller is a fulcrum and press A method of dividing the wiring board region 102 along the dividing groove 105 by using the working roller as an operating point is employed. The distance from the center of the axis of the transfer roller to the center of the axis of the pressing roller in plan view is set to match the length of one side of each wiring board region 102. The transfer roller and the pressure roller are installed in contact with the endless belts respectively. By transferring the mother substrate 101 between the upper and lower endless belts, the transfer roller serves as a fulcrum and the press roller serves as an action point. The mother substrate 101 is sequentially broken and divided along the dividing groove 105 above the transfer roller.

Further, the laser beam is irradiated along the boundary of each wiring board region 102 of the fired mother board 101, and the metal layer 106 is caused by an ablation phenomenon (a phenomenon in which a part of the material is decomposed by evaporation or erosion).
In addition, since the split groove 105 is formed in the nickel plating layer 118, the gold plating layer 119, and the ceramic insulating layer 103, it is possible to form the split groove 105 having a good shape with reduced adhesion and excellent openability. is there. Therefore, when the mother board 101 is divided into the respective wiring board regions 102, defects such as burrs, chipping, and escaping that are likely to occur on the side surfaces of the wiring board can be further suppressed.

When the electronic component 121 is, for example, a piezoelectric vibration element, the piezoelectric vibration element that oscillates at a predetermined frequency is bonded to a pair of connection conductors 113 formed along the inner surface of the mounting portion 112 of the wiring board, such as a conductive adhesive. For example, an iron-nickel alloy or an iron-nickel-cobalt alloy is formed on the upper surface of the metal layer 106 that is electrically and mechanically joined by a material (not shown) and is formed on the upper surface of the wiring board so as to surround the mounting portion 112. The piezoelectric vibration element is hermetically sealed with a lid 111 made of a metal material such as a brazing material 110 such as a gold-tin alloy to constitute a piezoelectric device.

Here, the brazing material 110 for joining the lid 111 to the upper surface of the metal layer 106 is not limited to a gold-tin alloy, but may be a low melting point metal material such as a silver-tin alloy, a tin-zinc alloy, or solder. Good. Further, a metal frame body (not shown) is joined to the metal layer 106 with a brazing material 110 such as silver brazing, and a lid body 111 is seam welded or electron beam welded to the upper surface of the metal frame body to thereby provide a piezoelectric vibration element. May be hermetically sealed to constitute a piezoelectric device. In particular, a gold-tin alloy has a higher melting point than solder, and is not liable to be melted during reflow processing when mounted on an external circuit board, which is advantageous for high airtightness.

  Further, the gold-tin alloy is less expensive than Au, and unlike solder, does not contain harmful lead, and generates less outgas in joining to the wiring board. Therefore, a gold-tin alloy having a melting point of 217 to 320 ° C. and a tin content of 10 to 90% by mass can be preferably used.

In addition, when the protective layer 109 as described above is formed so that the thickness decreases from the bottom of the second divided groove 108 to the upper end of the first divided groove 107, the protective layer 109 is the uppermost gold layer. The possibility of rising to the upper surface of the plating layer 119 is reduced. Therefore, the flatness of the upper surface of the metal layer 106 to which the lid 111 is bonded can be ensured more reliably. Therefore, the lid 111 can be bonded to the metal layer 106 better. A mounting portion 112 is formed inside the metal layer 106, and the electronic component 121 is accommodated in the mounting portion 112. The electronic component 121 mounted on the mounting portion 112 has a lid 111 bonded to the upper surface of the metal layer 106 (the nickel plating layer 118 and the gold plating layer 119 covering the metal layer 106) via the brazing material 110. Hermetically sealed. By electronically sealing the electronic component on the mounting portion 112, an electronic device can be manufactured.

A method for manufacturing a multi-piece wiring board according to an embodiment of the present invention will be described. The manufacturing method of the multi-piece wiring board according to the embodiment includes a step of irradiating the first laser 116 with the focus shifted to the boundary of the wiring board region 102 to form the first divided groove 107, and the first divided groove 107. A second laser 117 is irradiated at the center of the bottom in the width direction to form a second divided groove 108 that is narrower than the bottom of the first divided groove 107 and the first divided Forming a protective layer 109 containing a glass component on the surface of the groove 107 and the second divided groove 108.

Since it is such a manufacturing method, the manufacturing method of the multi-piece wiring board which can provide the division | segmentation groove | channel 105 can be provided, suppressing the rising of the melt 120 to the upper surface of a frame part.

The frame portion in the example of the manufacturing method of this embodiment corresponds to the frame-shaped insulating layer 103 surrounding the mounting portion 112 as described above. A metal layer 106 is formed on the upper surface of the frame portion. The metal layer 106 is sequentially covered with a nickel plating layer 118 and a gold plating layer 119. The dividing groove 105 is actually a depth that penetrates the gold plating layer 119, the nickel plating layer 118, and the metal layer 106 from the upper surface of the gold plating layer 119 in the thickness direction and enters the upper surface of the mother substrate 101 (frame portion). It will be formed.

That is, first, the first dividing groove 107 is irradiated with the first laser 116 while shifting the focus with respect to the part to be processed. Since this laser is out of focus, the output per unit area is small. That is, the energy applied per unit area is small at the site processed by the laser. This energy is dispersed in a relatively wide range with respect to the part to be processed, that is, the upper surface of the mother substrate 101. Therefore, it is possible to provide the first divided groove 107 having a relatively wide width and a shallow depth while suppressing the generation of the melt 120. About the 1st division groove 107, it provides in the depth to the middle of the thickness direction of the metal layer 106. FIG. As a result, the first divided groove 106 can be easily formed by the laser 116 out of focus as described above. The second dividing groove 108 has a focal point of the second laser 117 with respect to the processed portion, and has a large output per unit area. Therefore, the second divided groove 108 having a narrow width and a depth deeper than that of the first divided groove 107 can be easily provided. The second dividing groove 108 is provided with a depth that penetrates the metal layer 106 in the thickness direction and enters the upper surface of the mother substrate 101. Since the laser 117 is in focus, the mother substrate 101 made of an aluminum oxide sintered body or the like can be easily processed. The melt 120 generated when the second divided groove 108 is provided is solidified on the inner side surface of the second divided groove 108 and the bottom of the first divided groove to form the protective layer 109. Therefore, it is possible to provide the dividing groove 105 while suppressing the rising of the melt 120 to the upper surface of the frame portion.

Specifically, the method for forming such a dividing groove 105 is shown in FIGS. 3A and 3B, FIGS. 4A and 4B, and FIGS. 5A and 5B. As described above, the first divided grooves 107 are formed by sparse the irradiation of the first laser 116 (the output per unit area is small) along the boundary 104 of the wiring board region 102 where the divided grooves 105 are formed. Further, the first divided groove 107 is formed along the center in the width direction of the bottom of the first divided groove 107 with the second laser 117 being densely irradiated (the output per unit area is large). . The output is adjusted in accordance with the processing accuracy such as the width and depth of the target dividing groove 105.

The thickness of the fired metal layer 106 is about 8 to 20 μm, the nickel plating layer 118 is about 2 to 10 μm, and the gold plating layer 119 is about 0.1 to 1.0 μm.
The total thickness is about 10 to 30 μm. A split groove 105 having a depth of about 30 to 80 μm including the metal layer 106, the nickel plating layer 118, and the gold plating layer 119 is formed on the mother substrate 101.

As the type of laser, for example, it is conceivable to use a YAG laser or a carbon dioxide laser. In the case of a carbon dioxide laser, when the laser is irradiated from above the metal layer 106 covered with the gold plating layer 119, the reflectivity to the metal layer 106 is high, but at the same time the processing point output is also very high, so the depth direction In addition, the ceramic insulating layer 103 can be grooved at a high processing speed. On the other hand, the laser irradiation by the carbon dioxide laser has a large thermal effect on the ceramic insulating layer 103, and even if the dividing groove 105 is formed, it cannot be formed into a V shape. There is a possibility that the dividing groove 105 (especially the second dividing groove 108) is filled and the function as the dividing groove 105 cannot be performed. Therefore, YA
It is preferable to use a G laser.

It is important that the laser to be irradiated as a YAG laser is a laser having a wavelength in the ultraviolet region. The laser having a wavelength in the ultraviolet region has a pulse frequency of 10 to 200 kHz by a solid laser, a pulse width of 5 ns or more, and a processing point output of 1 to 100 W, preferably about 1 to 40 W. Solid-state lasers with wavelengths in the ultraviolet region include lasers excited from crystals such as YAG, YVO ₄ , and YLF, and the optimum laser can be selected according to the pulse characteristics and workability of the workpiece. it can. In particular, a YAG laser having a pulse frequency of 10 to 100 kHz, a pulse width of 50 to 200 ns, and a processing point output of about 1 to 30 W and having a third harmonic (wavelength of 355 nm) is used from the viewpoint of processing accuracy and processing time of the dividing groove 105. It can be preferably used.
The fundamental wave or double wave laser by the solid laser has high reflectivity to the nickel plating layer 118 and the gold plating layer 119, and an excessive thermal load is generated to promote the precipitation of the glass component from the ceramic sintered body. For this reason, it is difficult to form the V-shaped dividing groove 105 that functions as the dividing groove 105.

Here, in the step of forming the first dividing groove 107, the nickel plating layer 118 and the gold plating layer 119 do not contain a glass component, and the metal layer 106 has a glass in the vicinity of the region in contact with the ceramic insulating layer 103. Contains ingredients. In addition, for example, the first dividing groove 107 is formed with a depth halfway in the thickness direction of the metal layer 106. Therefore, the metal layer 106, the nickel plating layer 118, and the gold plating layer 119 are thinly formed with the melt 120 containing the glass component (which becomes the protective layer 109). In the step of forming the second divided groove 108, the laser penetrates the metal layer 106 in the thickness direction, so that the melt 120 containing the glass component contained in the ceramic insulating layer 103 (which becomes the protective layer 109) However, the melt 120 is generated by the heat of the laser. This melt 120 is solidified so that the thickness decreases from the bottom of the second divided groove 108 to the upper end of the first divided groove 107 (there is an image that the second divided groove is blocked when “flowed”, The protective layer 109 is formed.

At this time, the second dividing groove 108 is formed to be narrower than the first dividing groove 107. A second divided groove 108 is formed in a part of the first divided groove 107 in the width direction. From this, the generated melt 120
The frame portion (gold plated layer 119) extends from the inside of the second dividing groove 108 to the opening portion of the first dividing groove 107.
) To the upper surface (sealing surface).

In order to prevent the melt 120 from rising onto the sealing surface, an organic film (for example, polyvinyl alcohol) that can be easily washed away may be formed on the sealing surface. The organic film needs to be extremely thin so as not to disturb the laser transmission. By irradiating the mother substrate 101 with a laser from above the organic film, the melt 120 rising on the organic film can be washed away together with the organic film. If polyvinyl alcohol is used as the organic film, the organic film can be easily washed away by washing with water or warm water without placing a burden on the environment. By laser processing the mother substrate 101 coated with an organic film in this manner, even if the melt 120 rises on the sealing surface, it can be easily removed.

Here, the dividing groove 105 formed on the main surface of the mother substrate 101 may be formed only on one main surface (upper surface) on which the metal layer 106 is formed, or on both main surfaces (upper and lower surfaces). It may be formed. When formed on both main surfaces, for example, a metal layer (not shown) on the lower surface side that becomes a mounting surface on an external electric circuit board does not require high-precision flatness. Therefore, the dividing groove 105 formed up to the ceramic insulating layer 103 with only one laser may be formed so as to face the upper dividing groove 105. The lower dividing groove extends from the metal layer serving as the mounting surface to the upper dividing groove 105 to the middle of the thickness of the ceramic insulating layer 103 surrounding the mounting portion 112 (that is, up to the boundary of the ceramic insulating layer 103 in the thickness direction). If formed deeply, the mother substrate 101 can be divided well.
In addition, it is possible to provide a method for manufacturing a multi-piece wiring board in which the rising of the melt 120 by the laser onto the surface of the gold plating layer 119 is suppressed.

Further, in the fired mother board 101, the boundary groove 104 between the adjacent wiring board regions 102 is subjected to laser processing twice to form the dividing groove 105 to a predetermined depth, so that a laser having a weak output per unit area is used. The dividing groove 105 can also be processed. In this case, it is possible to form the division grooves 105 with high dimensional accuracy even in the mother board 101 on which the small wiring board regions 102 are arranged, and to divide the mother board 101 along the boundary 104 of the wiring board area 102. This can be done more easily and reliably.

As a specific example, the thickness of the metal layer 106 including the nickel plating layer 118 and the gold plating layer 119 is 20
A mother substrate 101 having a thickness of 300 μm and a ceramic thickness of 300 μm is prepared, and as a laser processing condition, a YAG laser device having a wavelength of 355 nm is mounted for laser irradiation, and the mother substrate 101 is placed in one axis direction. Using a laser scribing device having a moving mounting table, the conditions were adjusted so that the machining point output was 3.8 W when the pulse frequency was 50 kHz.

Specifically, the above conditions were the same, and the processing speed was fixed at 60 mm / s. Further, the distance from the laser device of the laser scribing device to the upper surface of the workpiece was changed to adjust the laser irradiation diameter to 15 to 30 μm. Then, as shown in FIG. 5 (a), for the first laser 116, a first divided groove 107 having a laser irradiation diameter of φ30 μm, a depth of 25 μm, and a width of the widest portion of 33 μm is formed. did. Further, as shown in FIG. 5B, the second laser 117 is irradiated with the laser irradiation diameter focused on φ15 μm, so that the depth is 35 μm (the depth including the first dividing groove 107). 60 μm), and a second divided groove 108 having a width of the widest portion (the width of the bottom of the first divided groove 107) of 17 μm was formed along the center in the width direction of the bottom of the first divided groove 107. 5A and 5B are plan views schematically showing the steps of laser processing in the order of steps. In FIG. 5, parts similar to those in FIGS. 1 to 4 are denoted by the same reference numerals.

Usually, when the processing speed is constant, the required laser output increases as the dividing groove 105 to be processed is deepened. When forming the deep dividing groove 105, if the size of the laser output to be used is constant, the processing speed is slowed down and the upper surface of the workpiece (mother substrate 101) and its vicinity are
Excessive energy more than necessary must be irradiated. For this reason, the upper surface of the workpiece has a larger amount of processing per unit time, and a large amount of melt 120 is generated. Therefore, the amount of melt 120 that rises increases, and the width of the dividing groove 105 to be processed also increases. The problem arises that it becomes wider than necessary. If the output of the laser is too small, the dividing groove 105 having a predetermined depth cannot be processed. However, performing laser processing on the mother substrate 101 after firing in two steps in this way suppresses the rising of the melt 120 due to the laser onto the surface of the gold plating layer 119, and also enables division with high dimensional accuracy. This is very effective in forming the groove 105.

When the state of the dividing groove 105 of the mother substrate 101 subjected to laser processing is confirmed by a cross-sectional SEM photograph using a cross section, a protective layer 109 containing a glass component is formed on the surfaces of the first dividing groove 107 and the second dividing groove 108. It was confirmed that In addition, it was confirmed that the protective layer 109 was formed so as to be thin from the bottom of the second divided groove 108 to the upper end of the first divided groove 107. The thickness of the protective layer 109 at the bottom of the second divided groove 108 is about 9 μm, the thickness of the protective layer 109 at the top of the first divided groove 107 is about 3 μm, and a part of the protective layer 109 is the first divided groove. Although it was thinly formed on the upper surface of the gold plating layer 119 to be an opening portion of 107, it is a portion that is an area outside the outer periphery of the lid 111, and the melt 120 enters the sealing surface. Even if it rises, it can be easily removed by washing the organic film described above, and the sealing performance of the lid 111 is not hindered.

Note that the multi-cavity wiring board, the wiring board, and the manufacturing method of the multi-cavity wiring board of the present invention are not limited to the examples of the embodiments described above, and various methods are possible without departing from the gist of the present invention. You can make any changes. For example, in the example of the above embodiment, the metal layer 106 of the wiring board to which the lid 111 is bonded has the nickel plating layer 118 and the gold plating layer 119 attached to the upper surface. For example, iron-nickel-
A metal frame (not shown) made of a cobalt alloy may be joined. In addition, the laser scribing device uses a YAG laser, and the laser irradiation diameter is adjusted by changing the distance from the laser device to the top surface of the workpiece while fixing the processing point output and processing speed. Depending on the shape of the dividing groove 105, the laser type, processing point output, processing speed, and the like may be changed.

101 ... Mother board
102 ・ ・ ・ Wiring board area
103 ・ ・ ・ Ceramic insulation layer
104 ... Boundary
105 ・ ・ ・ Dividing groove
106 ・ ・ ・ Metal layer
107 ... 1st division groove
108 ... 2nd division groove
109 ... Protective layer
110 ... brazing material
111 ・ ・ ・ Cover
112 ・ ・ ・ Mounting part
113 ・ ・ ・ Wiring conductor
114 ... Disposal area
115 ... Plating terminal
116 ... 1st laser
117 ・ ・ ・ Second laser
118 ... Nickel plating layer
119 ... Gold plating layer
120 ... melt
121 ・ ・ ・ Electronic components

Claims (5)

A plurality of wiring board regions are arranged vertically and horizontally on a mother board formed by laminating a plurality of ceramic insulating layers containing a glass component, and a dividing groove is formed on the upper surface of the mother board along the boundary of the wiring board area It is a multi-cavity wiring board that has been
A metal layer is formed on the upper surface of the mother substrate;
The dividing groove is a first dividing groove provided from the upper surface of the metal layer to the middle of the thickness direction of the metal layer;
And a plurality of second divided grooves provided on the upper surface of the mother board through the metal layer from the bottom in the thickness direction. Wiring board. 2. The multi-piece wiring board according to claim 1, wherein inner surfaces of the first divided groove and the second divided groove are covered with a protective layer containing the glass component.   3. The multi-piece wiring board according to claim 2, wherein the protective layer has a thickness that decreases from a bottom portion of the second divided groove to an upper end portion of the first divided groove. The wiring board according to claim 1, wherein the multi-cavity wiring board according to claim 1 is divided along the dividing groove. Producing a mother substrate formed by laminating a plurality of ceramic insulating layers containing a glass component;
A plurality of wiring board regions are arranged vertically and horizontally on the mother board, and a first divided groove is formed on the upper surface of the mother board along the boundary of the wiring board area by irradiating the laser beam for the first time. And a process of
A step of forming a second divided groove having a width narrower than that of the bottom of the first divided groove by irradiating a laser beam for the second time while focusing on the widthwise center of the bottom of the first divided groove. When,
A method for manufacturing a multi-cavity wiring board, comprising:

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