JP2004095676A - Method for manufacturing thick film multilayer substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thick film multilayer substrate manufacturing method capable of reducing the aperture size of a via hole without increasing manufacturing costs. <P>SOLUTION: An unburned thick film insulator sheet (raw sheet) 54 on which a conductive printing layer 84 is formed and conductive paste is applied to the insides of via holes 28, 30 is laminated on a substrate 12, bonded by thermocompression bonding and then burned. However, the via holes 28, 30 formed by punching work can be reduced at its aperture size because the area of the aperture is not reduced in printing. Since the raw sheet 54 is bonded by thermocompression in the case of burning, contraction of the raw sheet 54 in the surface direction can be interrupted by the substrate 12. Consequently, positional deviations of wiring patterns 46, 40, via holes 28, 30, etc. due to large contraction in the face direction can be prevented without adding a specific process, so that mutual intervals between respective parts can be shortened. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a thick film multilayer substrate, and more particularly to a technique for interconnecting a plurality of stacked wiring layers.
[0002]
[Prior art]
For example, in the case of a thick-film multilayer substrate in which a plurality of wiring layers are stacked via an insulator layer, the wiring density is longer than that of a substrate having through holes penetrating all the layers. In some cases, a via hole (via hole) for penetrating only one or a plurality of layers and interconnecting the wiring of the upper and lower layers or the plurality of layers is provided.
[0003]
[Problems to be solved by the invention]
When manufacturing the via-hole substrate as described above, for example, a thick-film insulator paste is applied so as to cover the first wiring layer provided on the substrate by using a thick-film screen printing method, and the through-hole is formed. After forming an insulator layer having (via holes), a thick film conductor paste is applied on the insulator layer in a predetermined pattern to form a second wiring layer. The lower first wiring layer is provided with a land for connection to the upper second wiring layer, and the via hole is located on the land. Therefore, by applying a thick-film conductor paste into the via hole at the same time as forming the second wiring layer or in a separate step, the first wiring layer and the second wiring are formed using a through conductor generated from the conductor paste. The layers will be interconnected.
[0004]
However, in thick film screen printing, when the paste is applied, bleeding occurs between the screen and the substrate or a print pattern provided on the substrate, or the flow of the paste itself until the applied paste dries. Spreading based on gender is inevitable. Therefore, in consideration of the dimensional change due to these, in order to secure the connection via the via hole, for example, the opening size of the rectangular via hole needs to be designed to have a size of 200 (μm) or more on one side. . Further, in consideration of the displacement during the printing and lamination, the lands of the first wiring layer and the second wiring layer also need to have a size of 400 (μm) or more on one side in a rectangular shape. Therefore, in reducing the size of the multilayer thick film substrate, it has been an obstacle that these dimensions cannot be reduced.
[0005]
On the other hand, there has been proposed a low-temperature laminated substrate in which unfired thick film insulator sheets are laminated and fired to form a multilayer structure. When manufacturing this low-temperature laminated substrate, a thick-film insulator sheet is punched to form a via hole, a thick-film conductor paste is applied on the surface thereof in a predetermined pattern, and the thick-film conductor is placed in the via hole. After applying the paste, a plurality of thick film insulator sheets are laminated. According to such a low-temperature laminated substrate, since the via hole is formed by punching, it is possible to set the opening size to, for example, about 100 (μm). However, the low-temperature laminated substrate has a large shrinkage in the surface direction at the time of firing, for example, about 20 (%), and has a large variation in the in-plane shrinkage ratio. There is a disadvantage that the displacement occurs. For this reason, since the wiring pattern cannot be formed at a high density, it is difficult to reduce the size of the multilayer substrate even if the via holes can be reduced.
[0006]
For the purpose of suppressing and uniforming the shrinkage in the plane direction, for example, a method of baking while applying pressure, or a method of forming a laminate of a thick film insulator sheet as described in JP-A-11-224984. A method of thermocompression bonding an unsintered ceramic sheet having a sintering temperature sufficiently higher than both sides on both surfaces has been proposed. However, in the former case, the firing efficiency is remarkably reduced, and in the latter case, a new unfired ceramic sheet is required for each firing.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of manufacturing a thick-film multilayer substrate capable of reducing the size of an opening of a via hole without increasing the manufacturing cost. To provide.
[0008]
[Means for Solving the Problems]
In order to achieve such an object, the gist of the present invention resides in that a first wiring layer and a second wiring layer stacked on a substrate via an insulating layer are formed in via holes penetrating the insulating layer. A method for manufacturing a thick-film multilayer substrate mutually connected via a provided through conductor, comprising: (a) a first wiring layer forming step of forming the first wiring layer on the fired substrate; (B) a pressing step in which an unsintered thick film insulator sheet having the via hole at a predetermined position is superimposed on the substrate so as to cover the first wiring layer and thermocompression-bonded, and (c) a thickness in the via hole. A conductor application step of applying a film conductor paste, and (d) heating at a predetermined temperature to generate the insulator layer from the unfired thick film insulator sheet on the substrate, Firing to produce through conductors And the extent, lies in the fact that contain.
[0009]
【The invention's effect】
In this case, the unsintered thick film insulator sheet provided with via holes in advance is laminated on the substrate provided with the first wiring layer and thermocompression-bonded, and a thick film conductor paste for forming a through conductor is provided. Is applied in the via hole and a baking treatment is performed, whereby an insulator layer having a through conductor in the via hole is formed on the substrate. Therefore, the opening size of the via hole does not change due to bleeding or dripping as in the case of applying the thick film insulating paste on the first wiring layer. There is no problem in securing conduction between the wiring layer and the second wiring layer. At this time, since the thermocompression-bonded unfired thick film insulator sheet is thermocompression bonded to a fired substrate that cannot be shrunk at the firing temperature of the thick film, shrinkage in the plane direction is suppressed, There is no dimensional change or displacement of the pattern due to shrinkage. Further, the substrate on which the first wiring layer is provided constitutes a part of the thick-film multilayer substrate as it is, and no special device is required for suppressing the shrinkage of the thick-film insulator sheet. The production cost does not increase for the purpose. Therefore, the opening size of the via hole can be reduced without increasing the manufacturing cost.
[0010]
The first wiring layer can be formed by, for example, a thick film process or a thin film process, or by attaching a metal foil. For example, when the first wiring layer is formed by a thick film process, the baking process is performed before the laminating step. Alternatively, it may be performed simultaneously with the heat treatment for forming the insulator layer after the laminating step. That is, the phrase “to cover the first wiring layer” in the claims is not limited to the mode in which the formed first wiring layer is covered, but the unfired thick film printing layer generated in the first wiring layer. Is also included.
[0011]
The unsintered thick film insulator sheet is, for example, glass powder bonded with a resin, and may include a filler made of an inorganic pigment or an inorganic material powder, if desired.
[0012]
Other aspects of the invention
Here, preferably, the via hole is formed by performing a punching process on the unfired thick film insulator sheet. This makes it possible to easily obtain an unfired thick film insulator sheet in which via holes are formed in advance.
[0013]
Preferably, in the method of manufacturing a thick-film multilayer substrate, the conductor-coating step is performed prior to the pressure-bonding step, and simultaneously with applying a thick-film conductor paste in the via hole, the unfired thick-film insulating layer is formed. A thick film conductor paste for forming the second wiring layer is applied on the surface of the body sheet in a predetermined pattern. In this case, the thick-film conductor paste is less likely to bleed than in the case where a thick-film conductor paste for forming the second conductor layer is applied after the formation of the insulator layer, so that fine lines can be easily formed. In addition, there is an advantage that the conductive paste can be easily applied into the via holes.
[0014]
Preferably, a circuit component is fixed on the substrate between the first wiring layer and the insulator layer at a position connected to the first wiring layer. According to this configuration, the first wiring layer provided directly on the substrate has a smaller thickness than that of the second wiring layer provided on the insulator layer formed from the unsintered thick film insulator sheet. Since the fixing strength to the circuit component is high, the fixing strength of the circuit component fixed thereon is also increased. Therefore, the required reliability can be satisfied in a circuit component particularly requiring the durability reliability of the fixing strength.
[0015]
Preferably, the method for manufacturing a thick-film multilayer substrate includes a temporary press-bonding step of laminating and pressing a plurality of unsintered thick-film insulator sheets each coated with a thick-film conductor paste in a predetermined pattern. In the laminating step, the temporarily pressed laminate is thermocompression-bonded onto the substrate. This makes it possible to more easily manufacture a multilayer substrate in which three or more conductor layers are stacked via an insulator layer.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0017]
FIG. 1 is a cross-sectional view illustrating an example of a layer configuration of a thick-film multilayer substrate 10 manufactured using the manufacturing method of the present invention. In the figure, a thick film multilayer substrate 10 is made of, for example, alumina (Al). ₂ O ₃ ), The first wiring layer 20, the second wiring layer 22, and the third wiring layer 24 are sequentially stacked on the one surface 14 of the substrate 12 formed of the first insulating layer 16 and the second insulating layer 18. It consists of. The insulator layers 16 and 18 are made of, for example, B ₂ O ₃ -SiO ₂ -Al ₂ O ₃ It is a thick-film insulator mainly composed of, for example. The wiring layers 20, 22, 24 are made of a thick-film conductor such as thick-film copper or thick-film silver. The insulator layers 16 and 18 have a thickness of, for example, about 20 (90 μm), for example, about 30 (μm), and the wiring layers 20, 22, and 24 have a thickness of, for example, 5 to 30 (μm). ), For example, about 15 (μm).
[0018]
The first insulator layer 16 is located at an appropriate position on the thick film conductor 26 forming the first wiring layer 20, and the second insulator layer 18 is positioned on the thick film conductor 26 forming the second wiring layer 22. Are provided with via holes 28 and 30 that penetrate each in the thickness direction. The thick film conductor 26 of the second wiring layer 22 is located on the former via hole 28, and the thick film conductor 26 of the third wiring layer 24 is located on the latter via hole 30. Therefore, a part of the thick film conductor 26 enters the via holes 28 and 30, and the first wiring layer 20 and the second wiring layer 22, and the second wiring layer 22 and the third wiring layer 24 form the via holes 28 and 30. They are interconnected via holes 28 and 30. In the present embodiment, a portion of the thick film conductor 26 that enters the via holes 28 and 30 corresponds to a through conductor.
[0019]
FIG. 2 shows an example of the wiring pattern 32 appearing on the surface of the thick film multilayer substrate 10, that is, the pattern of the third wiring layer 24 located at the uppermost layer. The wiring pattern 32 includes a plurality of component lands 34 for mounting electronic components (not shown), a plurality of connection terminals 36 for attaching the thick film multilayer board 10 to a predetermined position of a mechanical device (not shown) in an electrically connected state, A connection portion 38 for connecting to the second wiring layer 22 located on the lower side, a connection terminal 36 and a wiring 40 for connecting the connection portion 38 to each other are provided. Since the via hole 30 is provided below the connection portion 38, the thick film conductor 26 for forming the connection portion 38 enters the via hole 30 and becomes a through conductor. Although not shown, the first wiring layer 20 and the second wiring layer 22 are also formed with a wiring pattern that is substantially different from the wiring pattern 32, but extends over substantially the entire surface. Electronic components such as thick film resistors are mounted on the wiring patterns as necessary.
[0020]
FIG. 3 is an enlarged view of one of the connection portions 38 to explain a planar positional relationship between the via hole 30 and the connection portion 38. In the wiring pattern 42 of the second wiring layer 22 indicated by a broken line in the figure, a connection pad 44 is provided at a position substantially immediately below the connection portion 38. The connection pad 44 is formed, for example, at one end of the wiring 46 in the second wiring layer 22. For example, the connection portion 48 in the second wiring layer 22, that is, the connection in the first wiring layer 20 is formed via the wiring 46. It is connected to a pad 50 (see FIG. 1).
[0021]
Each of the connection portion 38 and the connection pad 44 has, for example, a substantially square shape with one side of about p = 300 (μm). The connection pad 44 has a peripheral portion covered with the second insulator layer 18, and only an inner peripheral portion is exposed in an opening provided in the second insulator layer 18, that is, in the via hole 30. For this reason, the via hole 30 has an area slightly smaller than the connection pad 44, and is entirely located on the connection pad 44. The planar shape of the via hole 30 is, for example, circular, and the diameter is about v = 100 (μm). 1 and 3, the via hole 28 has the same configuration as the via hole 30. That is, the connection pad 50 has its peripheral edge covered with the first insulator layer 16, and the via hole 28 is located on the inner peripheral part.
[0022]
As described above, as a result of the formation of the connection pads 44 and 50 and the via holes 28 and 30 in small dimensions, the wiring density of the thick-film multilayer substrate 10 is increased as compared with the related art. That is, conventionally, the length of one side of the connection pad is at least about 400 (μm), but according to the present embodiment, the length of one side of the connection pads 44 and 50 is at least 100 (μm). μm) is short, and is about 75% or less thereof, so that the distance between the wirings can be made at least about 100 to 200 (μm) smaller than in the related art.
[0023]
By the way, the above-mentioned thick-film multilayer substrate 10 is manufactured by laminating separately manufactured thick-film insulator sheets and alumina substrates, for example, as shown in FIG. Hereinafter, the manufacturing method will be described with reference to FIG. 4 while referring to FIG. 5 and FIG.
[0024]
First, in the manufacturing process of the unsintered thick-film insulator sheet, in the unsintered thick-sheet insulator forming step 52, for example, by using a sheet forming method such as a doctor blade method, an unsintered thick-film insulator sheet 54 (hereinafter referred to as a raw sheet) 54). The slurry used at this time is, for example, a glass powder or a glass powder and an inorganic filler and a resin powder or the like dispersed in a solvent, that is, the same constituent material as that used for forming a thick film was prepared to have a low viscosity. Things.
[0025]
Next, in the punching / punching step 56, the raw sheet 54 is punched after punching the raw sheet 54 using, for example, a press machine, or is punched at the same time as the punching, so that the raw sheet 54 has a predetermined size corresponding to the substrate size. And the via holes 28 (30) are formed at a plurality of predetermined locations. In the case of the latter method, the punching process may be performed using a metal mold having pins at positions where the via holes 28 and the like are formed.
[0026]
Next, in a conductor pattern printing step 58, a thick film conductor paste is applied to the raw sheet 54 having the via holes 28 (30) in a predetermined pattern by using, for example, a thick film screen printing method. FIG. 5 schematically shows an implementation state of this step. The raw sheet 54 is placed on a printing table 60, and a screen plate 64 having a screen 62 having a predetermined opening pattern is disposed above the raw sheet 54. Printing of the conductor pattern is performed by supplying the thick film conductor paste 66 onto the screen 62 and sliding the squeegee 68 along one direction while pressing down the screen 62. At this time, since the opening pattern of the screen 62 is also provided on the via hole 28 (30), the thick film conductor paste 66 for forming the wiring pattern is applied on the surface 70 and the via hole 28 (30) is formed at the same time. 30), the thick film conductor paste 66 is applied (filled, for example). The thick-film conductor paste 66 is made of, for example, conductor powder such as copper powder and silver powder, glass powder, resin, and solvent. The conductor print layer 84 is obtained by subjecting the thick film conductor paste 66 thus applied to a drying treatment. If a predetermined thickness cannot be obtained by one printing, after drying, printing and drying are repeated as many times as necessary.
[0027]
Returning to FIG. 4, in a temporary press-bonding step 72, for example, two raw sheets 54 that have been separately processed are overlapped and pressurized to temporarily press-bond them. At this time, their relative positions are determined with high accuracy by, for example, inserting a pin provided in the crimping device into the hole 92 of the raw sheet 54, as in the laminating step 82 described later.
[0028]
In FIG. 4, two manufacturing steps of the same raw sheet 54 are described. As described above, since the thick-film multilayer substrate 10 includes the two-layer thick-film insulator layers 16 and 18, the second wiring layer 22 and the third wiring layer 24 are formed on the substrate 12. Raw sheets 54 each provided with a conductor printing layer 84 are stacked. Therefore, as shown in the figure, two raw sheet manufacturing steps are provided. That is, the steps of manufacturing the raw sheet 54 are performed in a number corresponding to the number of sheets laminated on the substrate 12. Therefore, when only one raw sheet 54 is laminated on the substrate 12, only one manufacturing process is performed, and when three raw sheets 54 are laminated, three manufacturing processes are performed. .
[0029]
On the other hand, in the substrate manufacturing process, first, in the substrate raw sheet forming step 74, an unsintered ceramic sheet is formed by a sheet forming method such as a doctor blade method in the same manner as in the insulator raw sheet forming step 52 described above. . The slurry used at this time is, for example, ceramic powder such as alumina powder and resin dispersed in a solvent. Next, in a punching / punching step 76, the formed substrate green sheet is cut into an appropriate size according to a subsequent step, and a positioning hole 88 for positioning in a laminating step 82 described later is formed.
[0030]
Next, in a baking step 78, the punched substrate raw sheet is subjected to a baking treatment at a predetermined temperature determined according to the raw material composition. Thus, the organic components in the raw substrate sheet are burned off and the ceramic particles are sintered at the same time, and the substrate 12 is obtained. In the conductor pattern printing step 80, a thick film conductor paste is applied to the sintered substrate 12 in a predetermined pattern using, for example, a thick film screen printing method in the same manner as in the conductor pattern printing step 58, and dried. By performing the processing, the conductor print layer 84 for forming the first wiring layer 20 including the connection pads 50 and the wirings 51 is formed.
[0031]
Next, in the laminating step 82, the laminate of the raw sheet 54, which is separately formed and temporarily compressed, is stacked on the substrate 12 on which the conductor print layer 84 is provided as described above, and is heated while being pressed. These are thermocompressed. FIG. 6 shows an implementation state of the laminating step 82. In the figure, the substrate 12 is placed on the lower pressing surface 86 of the crimping device. As described above, the substrate 12 is provided with the positioning hole 88, and the substrate 12 is provided at a position corresponding to the lower pressing surface 86 so that the surface on which the conductor print layer 84 is formed faces upward. The positioning pin 90 is pierced into the positioning hole 88 to be positioned. In addition, a total of four positioning holes 88 are provided, for example, one at each of the four corners of the substrate 12.
[0032]
The pre-pressed raw sheet 54 is superimposed on the substrate 12 thus positioned, and the raw sheet 54 is also provided with positioning holes 92 at positions corresponding to the positioning holes 88 as shown in the figure. The substrate 12 and the raw sheet 54 are positioned by inserting the positioning pins 90 into the positioning holes 92. The raw sheet 54 is overlaid on the substrate 12 with the surface 70 on which the conductor print layer 84 is provided facing upward, and the via holes 28 (30) are formed on the substrate 12 at positions corresponding to the connection pads 50. Therefore, they are connected by being superimposed with a predetermined relative positional accuracy.
[0033]
In addition, in the figure, for convenience of explanation, a case is shown in which one raw sheet 54 that has not been temporarily crimped is laminated. Further, at the stage shown in the figure, since the conductor print layer 84 has not been fired, the connection portions 44 and the wirings 46 and the like have not been formed yet, but are denoted by the same reference numerals as those after firing for convenience. Further, the wiring pattern shown in the figure is simplified for convenience of explanation, and the conductor print layer 84 is actually formed at a very high density on both the substrate 84 and the raw sheet 54.
[0034]
Returning to FIG. 4, in the baking step 94, the substrate 12 thermocompressed as described above is subjected to a baking treatment at the baking temperature of the raw sheet 54. As a result, the organic components contained in the raw sheet 54 and the conductor print layer 84 are burned off, and the glass powder and the conductor powder are sintered, so that the first insulator layer 16 and the second insulator layer 18 described above are sintered. Are generated, a thick-film conductor layer, that is, a first wiring layer 20, a second wiring layer 22, and a third wiring layer 24, which are stacked via the layers, are generated. The substrate 12 is, for example, a plurality of thick film multilayer substrates 10 from which one is to be manufactured. The substrate 12 is divided into individual substrates after the firing process is completed as described above. The above-mentioned thick film multilayer substrate 10 is obtained. In FIG. 6, one sheet is shown for convenience.
[0035]
In the above-described manufacturing process, in this embodiment, the unprinted thick film insulator sheet 54 in which the conductor print layer 84 is formed and the conductor paste 66 is applied in the via holes 28 and 30 is laminated on the substrate 12. After the thermocompression bonding, a baking process is performed. For this reason, the via holes 28 and 30 formed by the punching process cannot reduce the opening area during printing as compared with the via holes formed by printing and laminating the thick-film insulator paste, and thus the above-described process is performed. Such a small opening size can be provided. In addition, when the firing step 94 for fixing the insulator layers 16, 18 and the wiring layers 20, 22, 24 on the substrate 12 is performed, since the raw sheet 54 is thermocompression-bonded, the firing of the thick film material is performed. The substrate 12 that is not allowed to shrink at the temperature prevents the raw sheet 54 from shrinking in the plane direction. Therefore, even if a special process is not provided, the wiring caused by a large shrinkage in the plane direction, such as a conventional low-temperature fired substrate in which the firing process is performed in a state where only the unfired thick film insulator sheet 54 is laminated. Since there is no displacement of the patterns 32, 42, the via holes 28, 30, and the like, the distance between them can be reduced. As described above, the opening dimensions of the via holes 28 and 30 can be reduced without increasing the manufacturing cost.
[0036]
In the present embodiment, the via holes 28 and 30 are provided by punching the raw sheet 54. Therefore, there is an advantage that the via holes 28 and 30 having high dimensional accuracy can be easily obtained as compared with the case of forming by thick film printing.
[0037]
Further, in this embodiment, prior to laminating the substrate 12 and the raw sheet 54, a thick-film conductor paste is applied in the via holes 28 and 30, and at the same time, the conductor print layer 84 is formed on the surface of the raw sheet 54. Provided. Therefore, bleeding of the thick film conductor paste is less likely to occur than in the case where the thick film conductor paste for forming the wiring layers 22 and 24 is applied after the formation of the insulator layers 16 and 18 (that is, after firing). In addition, there is an advantage that the formation of the fine line is facilitated, and the application of the conductive paste into the via holes 28 and 30 is facilitated.
[0038]
Further, in the present embodiment, after the two unsintered thick film insulator sheets 54 are laminated and temporarily press-bonded, and then thermocompression-bonded on the substrate 12, the three wiring layers 20, 22, 24 are formed. The multilayer substrate 10 laminated via the insulator layers 16 and 18 can be manufactured more easily.
[0039]
Further, according to the present embodiment, the thick film multilayer substrate 10 is manufactured by laminating and firing the green sheet 54 on the substrate 12 made of alumina. As compared with the above, since the mechanical strength of the substrate 12 is high, there is also an advantage that the thick film multilayer substrate 10 is hardly damaged. Moreover, since the thermal conductivity of alumina is about 10 to 20 times that of the glass / ceramics constituting such a low-temperature fired substrate, there is an advantage that a thick-film multilayer substrate 10 with high heat dissipation can be obtained. is there.
[0040]
In the present embodiment, the first wiring layer 20 can use the thick film resistor paste developed for the alumina substrate, so that a thick film resistor having high durability reliability and a small temperature coefficient of resistance can be used. There are also advantages that can be provided.
[0041]
As described above, the present invention has been described in detail with reference to the drawings. However, the present invention can be implemented in other embodiments.
[0042]
For example, in the embodiment, the case where the present invention is applied to the thick film multilayer substrate 10 including the substrate 12 made of alumina has been described. However, various insulating materials such as other ceramics, glass, or enamel may be used for the substrate. 12 can be used instead.
[0043]
In the embodiment, the insulator layers 16 and 18 are made of B ₂ O ₃ -SiO ₂ -Al ₂ O ₃ And the like, and the wiring layers 20, 22, and 24 are made of a thick-film conductor such as a thick-film copper or a thick-film silver. It is appropriately changed according to the application of the multilayer substrate 10.
[0044]
In the embodiment, the positioning between the substrate 12 and the raw sheet 54 is performed based on the fitting between the positioning pins 90 and the positioning holes 88 and 92. Can be used.
[0045]
Further, in the embodiment, a case where the present invention is applied to a method of manufacturing a thick film multilayer substrate 10 in which three wiring layers 20, 22, and 24 are stacked via two insulating layers 16 and 18 is described. As described above, a thick-film multilayer substrate in which two wiring layers are stacked via an insulator layer and a thick-film multilayer substrate in which four or more wiring layers are stacked via an insulator layer The invention applies equally.
[0046]
Further, in the embodiment, the first wiring layer 20 provided on the substrate 12 is a thick-film conductor formed by using a thick-film screen printing method. It can be formed by attaching a foil or the like.
[0047]
In the embodiment, the first wiring layer 20 is fired in the firing step 94 together with the second wiring layer 22, the third wiring layer 24, and the insulator layers 16 and 18, but the firing of the first wiring layer 20 is performed. By performing the laminating step 82 after the processing, in the firing step 94, only the generation of the insulator layers 16 and 18 from the raw sheet 54 and the generation of the second wiring layer 22 and the third wiring layer 24 are performed. You may comprise.
[0048]
In the embodiment, the via holes 28 and 30 have a circular shape. However, the shape of the via holes 28 and 30 may be appropriately changed according to the required wiring density, manufacturing process, and the like. Various shapes such as a square shape can be adopted.
[0049]
Although not specifically exemplified, the present invention can be variously modified without departing from the gist thereof.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a layer configuration of a thick-film multilayer substrate manufactured by applying a manufacturing method according to an embodiment of the present invention.
FIG. 2 is a plan view showing a wiring pattern provided on a surface of the thick film multilayer substrate of FIG. 1;
FIG. 3 is a plan view illustrating a state of connection between conductor layers via via holes in the thick-film multilayer substrate of FIG. 1;
FIG. 4 is a process diagram illustrating a main part of a method for manufacturing the thick-film multilayer substrate of FIG. 1;
FIG. 5 is a diagram illustrating a process of applying a conductive paste to a thick film insulator sheet during the manufacturing process of FIG. 4;
FIG. 6 is a diagram illustrating a step of laminating a printed thick film insulator sheet on a substrate in the manufacturing process of FIG. 4;
[Explanation of symbols]
12: Substrate
28, 30: Via hole
32, 42: Wiring pattern
54: Unfired thick film insulator sheet (raw sheet)
66: Thick film conductor paste
84: printed conductor layer

Claims (3)

A thick-film multilayer substrate in which a first wiring layer and a second wiring layer laminated on a substrate via an insulating layer are connected to each other via a through conductor provided in a via hole penetrating the insulating layer. The method of manufacturing
A first wiring layer forming step of forming the first wiring layer on the fired substrate;
A compression bonding step of laminating an unfired thick film insulator sheet having the via hole at a predetermined position on the substrate so as to cover the first wiring layer and thermocompression bonding;
A conductor application step of applying a thick film conductor paste in the via hole,
Heating at a predetermined temperature to generate the insulator layer from the unfired thick film insulator sheet on the substrate and simultaneously generate the through conductor from the thick film conductor paste. Of manufacturing a thick film multilayer substrate. 2. The method according to claim 1, wherein the via holes are formed by punching the unsintered thick film insulator sheet. The conductor applying step is performed prior to the crimping step, and a thickness for forming the second wiring layer on the surface of the unfired thick film insulator sheet while applying a thick film conductor paste in the via hole. 3. The method according to claim 1, wherein the film conductor paste is applied in a predetermined pattern.

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