JP5921074B2 - Manufacturing method of laminated substrate - Google Patents

Description

  The present invention relates to a method for producing a laminated substrate and a laminated substrate produced by the method, and more particularly to a method for producing a laminated substrate having an insulating layer laminated thereon and a laminated substrate produced by the method.

  Conventionally, a method of manufacturing individual substrates by dividing an aggregate substrate is known. For example, as shown in the plan view of FIG. 10A and the cross-sectional view of FIG. 10B, the aggregate substrate 1 on which the divided grooves 3 and 4 are formed is cut along the divided grooves 3 and 4 (for example, Patent Document 1).

JP 2003-347684 A

  A multilayer substrate on which ceramic insulating layers are laminated is produced by laminating and firing ceramic green sheets. When manufacturing a ceramic multilayer substrate from an aggregate substrate, after firing the aggregate substrate on which the ceramic green sheets are laminated, the individual substrate is divided from the sintered aggregate substrate and the individual substrate is divided from the unfired aggregate substrate Then, there is a method of firing an unfired individual substrate.

  When the individual substrate is divided from the sintered aggregate substrate as in the former, the manufacturing process becomes simpler and more efficient than the firing of the unfired individual substrate divided from the aggregate substrate as in the latter.

  However, when firing in the state of an aggregate substrate, the regions that become the individual substrates are constrained, and cracks are likely to occur due to internal stress during firing. Further, when the individual substrate is divided from the sintered aggregate substrate, cracks spread and defects are likely to occur in the individual substrate. Furthermore, the characteristics of the element formed on the laminated substrate may be deteriorated by the residual stress after firing.

  In view of such circumstances, the present invention can relieve internal stress at the time of firing, suppress the spread of cracks at the time of division, and reduce the residual stress after firing, and the multilayer substrate manufactured by the method. Is to provide.

  In order to solve the above-described problems, the present invention provides a method for manufacturing a laminated substrate configured as follows.

The manufacturing method of the laminated substrate is as follows: (i) one layer or two or more layers of unfired upper insulating layer and one layer or two or more layers of unfired lower insulating layer. A first step of forming an unfired collective substrate including individual substrate regions that are laminated so as to sandwich a fired intermediate insulating layer, and (ii) the unfired collective substrate a second step of firing, a third step of dividing the assembled board (iii) firing already, is cut along the boundary lines of the individual substrate region, the number board from the collective board Is provided. In the first step, the intermediate insulating layer includes a magnetic ferrite layer in which a coil is formed including a magnetic ceramic material, and the intermediate insulating layer among the upper insulating layer, the lower insulating layer, and the intermediate insulating layer. A through hole including a part of the boundary line of the individual substrate region is formed in advance in at least one layer of only the insulating layer, and a cavity is formed in the collective substrate by the through hole. The through hole formed in the intermediate insulating layer includes a portion where the boundary line of the individual substrate region intersects, and continuously penetrates all the magnetic ferrite layers in which the coil is formed in the stacking direction. It is formed to do.

  According to the above method, internal stress is generated in the aggregate substrate by firing the aggregate substrate in the second step. At this time, since the internal stress around the cavity is relieved in the collective substrate, the internal stress at the time of firing can be relieved and the generation of cracks can be suppressed.

  When the collective substrate is divided in the third step, since a cavity including the boundary line of the individual substrate region is formed inside the collective substrate, it is possible to suppress the spread of cracks during the division.

  Furthermore, by forming through holes in the intermediate layer, residual stress can be reduced in the divided individual substrates.

In the above method , the through hole formed in the intermediate insulating layer is formed to include a portion where the boundary line of the individual substrate region intersects.

  In this case, the intermediate insulating layers in which the through holes are formed are connected to each other at intermediate portions where the adjacent individual substrate regions are separated from the four corners.

In the above method, the intermediate insulating layer in which the through holes are formed include a magnetic ferrite layer a magnetic ceramic material unrealized coils are formed.

  In this case, in the intermediate insulating layer in which the coil is formed, the residual stress is relaxed by the through hole, and the magnetostriction caused by the residual stress is relaxed. Thereby, characteristic deterioration of the inductor element formed by the coil (decrease in the inductance of the coil due to iron loss) can be reduced.

  Preferably, in the first step, the aggregate substrate in which a material that disappears when the unfired laminated body is fired in the second step is formed in the through hole.

  In this case, the material disposed in the through hole disappears when the unfired aggregate substrate is fired in the second step. Thereby, a cavity is formed inside the collective substrate.

Wherein the laminated substrate divided into the number board from the collective substrate by the third process, the peripheral surface of the intermediate insulating layer prior SL through holes are formed by the through hole, the upper insulating layer and the lower A recess recessed from the peripheral end surface of the insulating layer is formed.

  The multilayer substrate having the above configuration can relieve internal stress during firing, can suppress the spread of cracks during division, and can reduce residual stress after firing.

  According to the present invention, the internal stress during firing can be relaxed, the spread of cracks during division can be suppressed, and the residual stress after firing can be reduced.

It is sectional drawing of a laminated substrate. Example 1 It is principal part sectional drawing of an aggregate substrate. Example 1 It is sectional drawing of a laminated substrate. ( Reference Example 1 ) It is principal part sectional drawing of an aggregate substrate. ( Reference Example 1 ) It is principal part sectional drawing of an aggregate substrate. (Modification 1) It is principal part sectional drawing of an aggregate substrate. (Modification 2) It is principal part sectional drawing of an aggregate substrate. (Modification 3) It is sectional drawing of a laminated substrate. (Comparative example) It is principal part sectional drawing of an aggregate substrate. (Comparative example) It is (a) top view and (b) sectional drawing of a ceramic substrate. (Conventional example)

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  Example 1 A laminated substrate 10a of Example 1 will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view of the multilayer substrate 10a. FIG. 2A is a cross-sectional view of the main part of the collective substrate cut along line AA in FIG. FIG. 2B is a cross-sectional view of a main part of the aggregate substrate cut along the line BB in FIG.

  As shown in FIGS. 1 and 2, the laminated substrate 10a cuts the collective substrate including the individual substrate regions 11a to 11d to be the laminated substrate 10a along the boundary lines 11x and 11y of the individual substrate regions 11a to 11d. To produce.

  As shown in FIG. 1, a laminated substrate 10a has land electrodes for mounting components 2, 4 and 6 such as surface mount components and IC chips on one main surface 12a of a substrate body 12 on which insulating layers are laminated. 26 is formed. On the other main surface 12b of the substrate body 12, an external electrode 28 for mounting the laminated substrate 10a on another circuit board or the like is formed. When the components 2, 4 and 6 are not mounted on the multilayer substrate 10a, the land electrode 26 can be eliminated.

  In the substrate body 12, a first nonmagnetic ferrite layer 16a, a first magnetic ferrite layer 14a, an intermediate nonmagnetic ferrite layer 16c, a second magnetic ferrite layer 14b, and a second nonmagnetic ferrite layer 16b are sequentially laminated. ing. Each layer 14a, 14b, 16a, 16b, 16c includes one or more insulating layers. The first nonmagnetic ferrite layer 16a is the upper insulating layer of the present invention. The second nonmagnetic ferrite layer 16b is the lower insulating layer of the present invention. The intermediate nonmagnetic ferrite layer 16c and the first and second magnetic ferrite layers 14a and 14b are intermediate insulating layers of the present invention.

  The first and second magnetic ferrite layers 14a and 14b include a magnetic ceramic material. For example, magnetic ferrite containing iron oxide, zinc oxide, nickel oxide and copper oxide as main components and a ceramic material are included. The first and second nonmagnetic ferrite layers 16a and 16b and the intermediate nonmagnetic ferrite layer 16c include, for example, nonmagnetic ferrite mainly composed of iron oxide, zinc oxide and copper oxide, and a ceramic material.

  A via hole conductor 24, a coil element 20, and a wiring conductor 22 are formed inside the substrate body 12 so as to constitute an electric circuit. The via-hole conductor 24 is formed so as to penetrate the insulating layer of the substrate body 12. The coil element 20 and the wiring conductor 22 are formed between adjacent insulating layers of the substrate body 12. A gap 18 is formed in the substrate body 12 adjacent to the coil element 20.

  The coil element 20 is formed on each of the first magnetic ferrite layer 14a, the intermediate nonmagnetic ferrite layer 16c, and the second magnetic ferrite layer 14b, and these are formed as via-hole conductors 22a and 22b (see FIG. 2A). And are spirally connected in the stacking direction to form a coil.

  Although not shown, a capacitor may be formed in the substrate body 12 by wiring conductors facing each other. In this case, an LC filter can be formed, or a module component including an LC resonance circuit can be formed.

  As shown in FIG. 1, a recess 40 is formed on the side surface 12 c of the substrate body 12. Specifically, on the peripheral end surfaces of the first and second magnetic ferrite layers 14a, 14b and the intermediate nonmagnetic ferrite layer 16c of the substrate body 12, the periphery of the first and second nonmagnetic ferrite layers 16a, 16b of the substrate body 12 is provided. A recess 40 that is recessed from the end faces 16s, 16t is formed.

  The recess 40 is formed by a part of the through hole 30 formed in advance in the first and second magnetic ferrite layers 14a and 14b and the intermediate nonmagnetic ferrite layer 16c of the aggregate substrate. That is, as shown in FIG. 2A, the first and second magnetic ferrite layers in which the through holes 30 are formed in a cross shape in advance so as to include the intersecting portions of the boundary lines 11x and 11y of the individual substrate regions 11a to 11d. By laminating the first and second nonmagnetic ferrite layers 16a and 16b in which the through-hole 30 is not formed as shown in FIG. 2B on both sides of 14a and 14b and the intermediate nonmagnetic ferrite layer 16c, A cavity is formed inside the collective substrate. By cutting this collective substrate along the boundary lines 11x and 11y, the recess 40 is formed.

  As shown in FIG. 2 (a), the first and second magnetic ferrite layers 14a and 14b and the intermediate nonmagnetic ferrite layer 16c in which the through holes 30 are formed are formed by the adjacent individual substrate regions 11a to 11d. They are connected to each other at an intermediate portion away from the four corners.

  Next, the manufacturing process of the multilayer substrate 10a will be described.

  (1) First, the first and second magnetic ferrite layers and the intermediate nonmagnetic ferrite layer are laminated so as to be sandwiched between the unfired first and second nonmagnetic ferrite layers. An unfired collective substrate including individual substrate regions to be individual substrates is formed. At this time, in the first and second magnetic ferrite layers and the intermediate nonmagnetic ferrite layer, a through hole including a crossing portion of the boundary line of the individual substrate region and a portion continuing to the crossing portion is formed in advance, Thus, a cavity is formed inside the collective substrate.

  Specifically, ceramic green sheets containing magnetic ferrite mainly composed of iron oxide, zinc oxide, nickel oxide and copper oxide are used as the unfired first and second magnetic ferrite layers. Ceramic green sheets mainly composed of iron oxide, zinc oxide and copper oxide are used for the first and second nonmagnetic ferrite layers and the intermediate nonmagnetic ferrite layer.

  In the ceramic green sheet, a through hole is formed at an appropriate position by laser processing, punching processing, or the like, and a portion that becomes a via hole conductor after firing is disposed by embedding a conductive paste in the through hole by printing or the like. Also, by printing a conductor paste on one main surface of the ceramic green sheet by screen printing or gravure printing, or by transferring a metal foil of a predetermined pattern shape, coil elements, wiring conductors, land electrodes, external A conductor pattern for forming an electrode is formed.

  A carbon paste that disappears during firing is applied on or under the conductor pattern for forming the coil element by printing or the like.

  Furthermore, the ceramic green sheets for the first and second nonmagnetic ferrite layers and the intermediate nonmagnetic ferrite layer are divided into individual substrates by laser processing, punching processing, etc. so as to include the intersections of the boundary lines of the individual substrate regions. A through-hole is formed.

  An unfired aggregate substrate is formed by laminating and pressing the ceramic green sheets in a predetermined order. A cavity including the intersection of the boundary lines of the individual substrate regions is formed inside the collective substrate.

  (2) Next, the unfired aggregate substrate is fired to sinter the ceramic green sheet and the conductor paste. At this time, the carbon paste burns and disappears, and a gap adjacent to the coil element is formed.

  (3) Next, the sintered aggregate substrate is cut along the boundary line of the individual substrate regions by dicing, and the individual substrates are divided from the aggregate substrate. The aggregate substrate may be divided by breaking. In this case, dividing breaking grooves are formed in the unfired aggregate substrate.

  When components are mounted on the land electrodes, the manufacturing process is simplified and the efficiency is improved by dividing the assembly substrate after mounting the components on the assembly substrate.

  Through the above steps (1) to (3), it is possible to obtain a laminated substrate that is divided from the aggregate substrate into individual substrates.

  When the laminated substrate is manufactured by the above process, even if internal stress occurs due to the difference in the linear expansion coefficient and the firing behavior between the coil element and the ceramic green sheet when firing the aggregate substrate in the step (2), The substrate is relieved of internal stress around the cavity. Thereby, the internal stress at the time of baking can be relieved and generation | occurrence | production of a crack can be suppressed.

  Further, when the collective substrate is divided in the step (3), since the cavity including the boundary line of the individual substrate region is formed inside the collective substrate, it is possible to suppress the spread of cracks during the division.

  Further, by forming a through hole including a crossing portion of the boundary line of the individual substrate region in the ceramic green sheet for the first and second nonmagnetic ferrite layers and the intermediate nonmagnetic ferrite layer, Residual stress can be reduced.

  By reducing the residual stress, the efficiency of the coil is improved. In other words, when magnetostriction is generated in the magnetic ferrite layer due to residual stress, the efficiency of the coil is reduced due to iron loss (decrease in inductance), but a through hole is formed in the magnetic ferrite layer to relieve the residual stress in the magnetic ferrite layer. As a result, the efficiency of the coil is improved.

  Although the internal stress is relieved around the air gap 18 by the air gap 18, the stress relieving effect hardly reaches near the boundary line of the individual substrate region. If a cavity including a part of the boundary line of the individual substrate region is formed in the collective substrate, the internal stress can be sufficiently relaxed in the vicinity of the boundary line of the individual substrate region.

  In the step (1), carbon paste that disappears during firing may be filled in the through holes for dividing the individual substrates of the ceramic green sheet by printing or the like. In this case, when the unfired aggregate substrate in which the ceramic green sheets are laminated and pressure-bonded is fired in the step (2), the carbon paste filled in the through holes disappears, and the boundary lines of the individual substrate regions are formed inside the aggregate substrate. A cavity including the intersecting portion is formed.

For <Reference Example 1> laminated substrate 10b of Example 1 is described with reference to FIGS.

  FIG. 3 is a cross-sectional view of the multilayer substrate 10b. 4 is a cross-sectional view of a principal part of the collective substrate cut along line AA in FIG.

As shown in FIGS. 3 and 4, the laminated substrate 10 b of Reference Example 1 is configured in substantially the same manner as the laminated substrate 10 a of Example 1. In the following description, the same reference numerals are used for the same components as in the first embodiment, and differences from the first embodiment will be mainly described.

  As shown in FIG. 3, the laminated substrate 10b has a recess 42 formed only in the insulating layer in which the coil element 20 is formed.

  As shown in FIG. 4, the recess 42 is formed by a through hole 32 including only an intermediate portion between the intersecting portions of the boundary lines 11 x and 11 y of the individual substrate regions 11 a to 11 d. The adjacent individual substrate regions 11a to 11d are connected to each other at the four corners.

  <Modification 1> FIG. 5 is a cross-sectional view of a main part of a collective substrate of Modification 1. As shown in FIG. 5, the through-hole 34 for forming a cavity in the collective substrate includes an intersection of the boundary lines 11x and 11y of the individual substrate regions 11a to 11d so as to eliminate the corners of the individual substrate regions 11a to 11d. To form a rectangle.

  <Modification 2> FIG. 6 is a cross-sectional view of a main part of a collective substrate of Modification 2. As shown in FIG. 6, in order to form a cavity in the collective substrate, the through hole 34a including the intersection of the boundary lines 11x and 11y of the individual substrate regions 11a to 11d and the boundary lines 11x and 11y of the individual substrate regions 11a to 11d And a through hole 32a including only an intermediate portion between the intersecting portions.

  <Modification 3> FIG. 7 is a cross-sectional view of the main part of the collective substrate of Modification 3. As shown in FIG. 7, in order to form a cavity in the collective substrate, a plurality of through holes 32b are provided at intervals in an intermediate portion between adjacent intersections of the boundary lines 11x and 11y of the individual substrate regions 11a to 11d. Form.

  <Comparative example> The laminated substrate 10x of a comparative example is demonstrated referring FIG.8 and FIG.9.

  FIG. 8 is a cross-sectional view of the multilayer substrate 10x. FIG. 9 is a cross-sectional view of a principal part of the collective substrate cut along line AA in FIG. As shown in FIGS. 8 and 9, no concave portion is formed on the side surface 12y of the substrate body 12x of the multilayer substrate 10x. In this case, when the individual substrate regions 11a to 11d are constrained when fired in the state of the collective substrate, cracks are likely to occur due to stress concentration near the boundary lines 11x and 11y of the individual substrate regions 11a to 11d. .

  On the other hand, when the collective substrate in which the cavity including the boundary line of the individual substrate region is formed by the through hole of the intermediate insulating layer as in Examples 1 and 2 and Modifications 1 to 3 is fired, The internal stress at the time of firing can be relaxed and cracking can be suppressed.

  <Summary> As described above, after firing the aggregate substrate in which the cavity including the boundary line of the individual substrate region is formed, and dividing along the boundary line of the individual substrate region, the internal stress during firing is reduced. It can alleviate, can suppress the spread of cracks during division, and can reduce the residual stress after firing.

  The present invention is not limited to the above embodiment, and can be implemented with various modifications.

2, 4, 6 Components 10a, 10b, 10x Multilayer substrate 11a-11d Substrate region 11x, 11y Border 12 Substrate body 12a, 12b Main surface 12c Side surface 12x Substrate body 12y Side surface 14a First magnetic ferrite layer (intermediate insulating layer) )
14b Second magnetic ferrite layer (intermediate insulating layer)
16a First nonmagnetic ferrite layer (upper insulating layer)
16b Second nonmagnetic ferrite layer (lower insulating layer)
16c Intermediate nonmagnetic ferrite layer (intermediate insulating layer)
16s, 16t peripheral end face 18 gap 20 coil element 22 wiring conductor 22a, 22b via hole conductor 24 via hole conductor 26 land electrode 28 external electrode 30 through hole 32, 32a, 32b through hole 34, 34a through hole 40, 42 recess

Claims (3)

One or more unfired intermediate insulation layers are sandwiched between one or more unfired upper insulation layers and one or more unfired lower insulation layers A first step of stacking and forming an unfired aggregate substrate including individual substrate regions to be a plurality of individual substrates;
A second step of firing the unfired aggregate substrate;
Said collective substrate already baked formed, by cutting along the boundary lines of the individual substrate region, a third step of dividing the number board from the collective board,
With
In the first step, the intermediate insulating layer includes a magnetic ferrite layer in which a coil is formed including a magnetic ceramic material, and the intermediate insulating layer among the upper insulating layer, the lower insulating layer, and the intermediate insulating layer. A through hole including a part of the boundary line of the individual substrate region is formed in advance in at least one layer of only the insulating layer, and a cavity is formed inside the collective substrate by the through hole, and formed in the intermediate insulating layer The formed through hole includes a portion where the boundary line of the individual substrate region intersects, and is formed so as to continuously penetrate all the magnetic ferrite layers in which the coils are formed in the stacking direction. A method for producing a laminated substrate, comprising:   The said 1st process WHEREIN: The said aggregate substrate by which the material which lose | disappears when baking the unbaked laminated body by the said 2nd process is arrange | positioned in the said through-hole is characterized by the above-mentioned. 2. A method for producing a laminated substrate according to 1. The laminated substrate divided from the collective substrate into the individual substrate in the third step is
Wherein the peripheral edge surface of said through holes are formed intermediate insulating layer by the through hole, wherein the recess recessed from the peripheral surface of the upper insulating layer and the lower insulating layer is formed, wherein Item 3. A method for producing a laminated substrate according to Item 1 or 2 .

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