JPH05283864A - Multilayer circuit board and manufacture thereof - Google Patents

Abstract

PURPOSE:To reduce warpage, cracks, peeling by providing an inner wiring pattern and a large area conductor pattern wider than the wiring pattern as the conductor pattern, and providing the conductor pattern containing Ag as a main ingredient at a place of a special range of the entire thickness of a multilayer circuit board from one main surface of the board. CONSTITUTION:A circuit board 1 is formed by integrally laminating conductor patterns 3 and insulating layers 2 formed of a green sheet of an insulating material. A large area conductor pattern 4 is generally ten times as wide as the width of an inner wiring pattern 5. A large area conductor pattern 6 has a total area per one insulating layer 30% or more and preferably 40% or more of the areas of main surfaces 11, 15 of the board. The pattern 5 is disposed at a place of 0.1-0.4t and more preferably 0.10t-0.35t from one main surface 15 when the thickness of the board 1 is t. If it is present on the other region without existing on this region, warpage, peeling, cracks are increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low temperature firing multilayer wiring board and a method for manufacturing the same.

[0002]

2. Description of the Related Art For increasing the density and multifunction of electronic circuits, 3
It is necessary to make a multilayer wiring of a substrate by a three-dimensional structure, a multilayer wiring substrate is often used, and a low temperature firing multilayer wiring substrate is used because a low resistance conductor material such as Ag can be used.

A low-temperature fired multilayer wiring board is mainly manufactured by the green sheet method as follows. That is, first, a glass composite of glass powder and refractory ceramic powder, or crystallized glass powder is prepared, binder resin,
A solvent or the like is added to form a slurry, which is formed into a sheet and dried to obtain a green sheet of an insulating material. Next, punch through holes for front and back connections on this green sheet, print the conductor paste on the sheet, and
Fill the through holes with conductive paste. Then, a plurality of sheets are aligned and laminated, heated and pressed to be integrated, and fired at about 1000 ° C or lower.

By the way, multi-layer wiring boards are also required to have multiple functions, and demands for adding functions such as capacitors and inductors are increasing. Regarding a multilayer wiring board with a built-in capacitor, Japanese Patent Publication No. 3-20918 proposes to form a capacitor part in a substantially central portion in the thickness direction of the board and form ceramic layers for internal wiring of equal thickness above and below the capacitor part. There is.

In this proposal, it is not disclosed whether or not it is a low temperature firing multilayer wiring board and the kind of conductor. However, in a low temperature fired substrate, when a conductor containing Ag as a main component is used and a large area capacitor electrode pattern exceeding 40% of the main surface area of the substrate is provided in the central portion in the thickness direction of the substrate, deformation such as warpage occurs. It has been found. In particular, when high-speed temperature increase or high-speed binder removal is performed during firing, interlayer peeling, deformation such as cracks or warpage becomes remarkable.

[0006]

SUMMARY OF THE INVENTION A main object of the present invention is to provide a low-temperature fired multilayer wiring board using a conductor containing Ag as a main component, even if a large-area conductor pattern such as a capacitor electrode is provided on the board. It is an object of the present invention to provide a multilayer wiring board that is extremely free from deformation, peeling, cracks and the like, and an advantageous manufacturing method thereof.

The present inventors have examined the mechanism of occurrence of substrate deformation and the like when a large area conductor pattern is provided. As a result, the following findings (a) to (c) have been obtained.

(A) Problems during binder removal The firing is carried out by placing the laminate on a setter. At the initial stage of firing, the main purpose is to thermally decompose and remove the binder resin, but at this time, the binder does not come out uniformly from the laminate, and the decomposition of the binder inside is delayed. At this time, since the bottom portion is in contact with the setter, an asymmetric binder distribution in which a large amount of binder remains in the asymmetric position below the substrate is formed during binder removal.

When the binder is decomposed, dimensional shrinkage is caused, and if an asymmetric and non-uniform binder distribution is generated, a large stress is applied to the molded body at the time of removing the binder, which causes warping, peeling, and cracks. In particular, at this time, the presence of large-area conductor patterns such as the capacitor electrode, the ground conductor, and the power supply conductor further promotes these. Also,
High-speed binder removal makes these more visible.

(B) Problems before and after the start of sintering When Ag is used for the conductor, Ag diffuses into the green sheet during the temperature rise. The diffused Ag lowers the softening point of the glass in the green sheet and lowers the sintering start temperature. For this reason, the presence of a large-area Ag conductor pattern accelerates the sintering of that portion more than others, and as a result, deformation occurs after firing is completed. In particular, when a large area pattern exists above and below the green sheet as in the capacitor section, it is remarkable in that area.

(C) Problems during production of green sheet When producing a green sheet, the raw material slurry is applied onto a carrier film, formed into a sheet, and dried. During this drying, the binder resin moves and the amount of resin on the carrier film side decreases. As a result, the forming density of the green sheet in the thickness direction becomes non-uniform, and firing deformation such as warpage occurs.

From these factors (a) to (c), it has been found that when a large area Ag conductor pattern is provided in the center of the substrate, the respective factors promote each other to cause various substrate defects.

By the way, as a countermeasure against (a), it is possible to perform the binder removal process for a long time. But,
This method is extremely disadvantageous in terms of mass productivity and cost increase and is not practical.

As measures against (b), the activity of the Ag powder may be lowered by coarsening, or the softening point of the glass of the sheet may be increased, but the conductor resistance may be increased or the sintering may be performed. Properties and sintering matching properties are deteriorated and it cannot be put to practical use.

Further, as a measure of (c), it is conceivable to alternately print the patterns on the front and back of the green sheet and stack them, but the front and back management requires labor in mass production and leads to an increase in the number of steps, which is practical. Not.

It is also conceivable that a load plate is placed on the laminate and fired, but it takes an extremely long time to remove the binder and it is necessary to consider the releasability between the load plate and the substrate. Not practical.

[0017]

Therefore, the present inventors have
We came to the idea that there may be a large-area pattern arrangement in which the above-mentioned factors (a) to (c) cancel each other out, and as a result of experiments, we reached the inventions (1) to (6) below. did.

(1) In a multilayer wiring board in which a conductor material pattern is formed and laminated on a green sheet of an insulating material and baked at 1000 ° C. or less to form a conductor pattern between a plurality of insulating layers, the conductor pattern is , An internal wiring pattern and a large-area conductor pattern wider than the internal wiring pattern, and having Ag as a main component, this large-area conductor pattern is
From one main surface of the multilayer wiring board, the total thickness t of the board is 0.1
A multilayer wiring board provided at a position of t to 0.4t.

(2) The large area pattern is 0.10 t
The multilayer wiring board according to (1) above, which is provided at a position of 0.35 t.

(3) The multilayer wiring board according to (1) or (2) above, wherein the large-area conductor pattern occupies 30% or more of the area of the main surface.

(4) The multilayer wiring board according to any one of (1) to (3), wherein the large-area conductor pattern is a plurality of capacitor electrode patterns formed on two or more insulating layers.

(5) The multilayer wiring board according to any one of the above (1) to (4), wherein the insulating material contains glass powder and refractory ceramic powder or crystallized glass powder.

(6) In manufacturing the multilayer wiring board according to any one of (1) to (5), the pattern is formed on the front surface side of each green sheet, and the front surface and the back surface of each green sheet are mutually formed. A method for manufacturing a multilayer wiring board, which is laminated so as to be in contact with each other and fired.

(7) The method for manufacturing a multilayer wiring board according to (6), wherein the large area pattern is fired so as to be located below the center.

[0025]

[Operation] (i) Warpage reduction (a) Non-uniform binder decomposition during binder removal,
The non-uniform distribution of the binder in the green sheet (c) is
When the green sheets are stacked with the front and back directions aligned and fired, a warp in a convex state is generated downward on the setter side. The presence of the large-area Ag conductor pattern on the lower side of the center cancels this warp by the action of (b).

(Ii) Prevention of peeling and cracking Decomposition of the binder resin does not proceed uniformly over the entire substrate during the removal of the binder of (a), and as shown in FIG. There is an undecomposed residual area of resin. The residual area is indicated by diagonal lines in the figure. Even after the middle stage of the binder removal process, the residual area does not shrink, and the binder decomposition proceeds in the form of a decrease in the residual binder resin concentration. Therefore, at the outer edge of the residual region, there is always a concentration gradient of the binder resin during the binder removal process. Since the ceramic molded body shrinks as the binder decomposes, the concentration gradient causes internal stress and is strong during the binder removal process at the outer edge of the binder residual area (near the center of the substrate and the lower part of the setter side substrate) shown in FIG. Exposed to stress. If a large-area conductor pattern is provided in this area, peeling and cracks are likely to occur. On the contrary, peeling and cracking can be prevented by avoiding this area (outer edge of binder remaining area). Specifically, near the upper surface of the substrate (decomposition progresses rapidly at the beginning of the binder removal process, then low concentration)
And inside the residual zone (degradation near gentle and uniform).
However, when the Ag conductor is provided over a large area near the upper surface of the substrate, the above-mentioned problem of substrate warpage occurs.

[0027]

[Specific Structure] The specific structure of the present invention will be described in detail below. FIG. 1 shows an example of a multilayer wiring board 1 of the present invention. The multilayer wiring board 1 of FIG. 1 has conductor patterns 3 respectively, and is formed by laminating and integrating six insulating layers 2 formed of green sheets of an insulating material.

In this example, three insulating layers 2 immediately below the uppermost layer are used.
The conductor pattern 3 is formed as an internal wiring pattern 4 such as a signal wiring or a coil conductor. The conductor pattern 3 is formed as a large-area conductor pattern 5 on the underlying two insulating layers 2, and these form the capacitor electrodes 61 and 65, and the capacitor portion 6 is built therein. ..

In such a case, the large-area conductor pattern 5
Is approximately 10 times or more wider than the wiring width of the internal wiring pattern, which is usually about 100 to 200 μm or less. The large-area conductor pattern 6 may be provided on the entire surface of the insulating layer, a part thereof, or a plurality of spaced-apart portions as shown in the drawing. The total amount per insulating layer is preferably 30% or more, and particularly preferably 40% or more of the area of the main surfaces 11, 15 of the substrate. In such a case, the effectiveness of the present invention is extremely high. When the capacitor section 6 is provided within a region of 0.1t to 0.4t from the one main surface 15, the total area per layer of each of the capacitor electrode layers of 2 to 3 or more layers is the main surface of the substrate. It is preferably about 90% or less of the area of 11, 15.

Such a large-area conductor pattern 5 has a thickness of 0.1 mm from one main surface 15 when the thickness of the substrate 1 is t.
t to 0.4t (effective digit 1 digit), more preferably 0.1
It is arranged at a position of 0t to 0.35t (two significant digits). If the large-area conductor pattern 6 is not present in this region but is present in another region, warping, peeling, and cracking will increase critically.

Further, the large-area conductor pattern 5 is formed by two or three or more layers on one or more insulating layers 2 constituting the capacitor section 6 like the capacitor electrodes 61, 65 shown in the figure. When it exists, the defect prevention effect of the present invention is doubled. Therefore, it is preferable that both the outermost surfaces of the capacitor portion 6, more specifically the capacitor electrodes 61 and 65 of the capacitor portion 6, both be within the range of 0.1t to 0.4t from the one main surface 15.

As described above, the effect of the present invention occurs when the capacitor portion 6 is provided within the area of 0.1t to 0.4t from one main surface, so that a large area conductor such as an earth electrode is further provided in the other area. Arrangement is also allowed. However, the total area of the large-area conductor patterns existing in the area from one main surface 15 to less than 0.1 t and more than 0.4 t is 0.1 t.
50 of the total area of the large area pattern within the area of 0.4 t
% Or less, particularly preferably 0 to 30%.

By forming the large-area conductor pattern in the region of 0.1t to 0.4t in this manner, the internal wiring pattern 4 such as a coil or a signal wiring is formed above the large-area conductor pattern as shown in FIG. Can be formed. As a result, the area of the main surface of the substrate can be reduced, and the size of the substrate can be reduced. Further, by providing the coil section above the capacitor section in this way, the capacitor section and the coil section are not arranged in parallel in the substrate, and as a result, the number of winding turns of the coil can be increased. Further, if the signal wiring portion is provided above the capacitor portion, the signal wiring can be freely routed without being divided by the capacitor portion, and the degree of freedom in wiring and circuit design can be increased. From these,
There is also a side effect of realizing a small wiring board having high characteristics.

In the present invention, the conductor material is mainly composed of Ag having a small specific resistance. Since the melting point of Ag is 960 ° C., the firing is preferably performed at 1000 ° C. or lower, particularly at 800 to 950 ° C. As Ag, it is preferable to use silver having a silver content of 90% by weight or more, particularly pure silver having a purity of 99.9% by weight or more, or Pd containing about 5% by weight or less of Pd. As described above, the specific resistance can be extremely reduced by using pure silver. As a method of forming the conductor pattern, a method of printing or transferring a conductor paste is generally used.

When forming a pattern with a conductor paste, it is preferable that the conductor powder such as silver powder to be used has an average particle diameter (major axis diameter when anisotropic) of about 0.5 to 20 μm. If the particle size is too small, the content of the inorganic component in the conductor paste decreases, and it becomes impossible to form a dense pattern. If the particle size is too large, it becomes difficult to form a pattern by screen printing, a transfer method or the like. The shape of the silver powder is not particularly limited, but a part or all of the silver powder may be scale-shaped. The content of the conductor powder (silver powder) in the conductor paste is 60 to 90% by weight, especially 7
It is preferably from 0 to 85% by weight. If the content is too small, the specific resistance may be reduced, or a part of the pattern after firing may be broken. On the other hand, if it is too large, the viscosity of the paste will increase, making pattern formation difficult.

A glass frit can be added to the conductor paste. As the glass frit contained in the conductor paste, it is preferable to use glass having a softening point of 700 to 850. The composition of the glass frit used is not particularly limited, but the following composition is particularly preferable.

SiO ₂ : 50 to 70% by weight Al ₂ O ₃ : 6 to 10% by weight One or more alkaline earth metal oxides: 18 to 30% by weight

In this case, as the alkaline earth metal oxide, 1 to 3 kinds of SrO, CaO and MgO are preferable. Further, ZrO ₂ or the like may be contained. The average particle size of the glass frit is not particularly limited, but usually 0.5
Approximately 2.0 μm is used.

The content of glass frit in the conductor paste is preferably 1 to 10% by weight. Further, the glass frit is preferably contained in an amount of 2 to 10% by weight with respect to the conductor powder. The conductor paste contains conductor powder such as silver powder and glass frit, as well as a vehicle. Examples of the vehicle include ethyl cellulose, polyvinyl butyral, methacrylic resin, a binder such as butyl methacrylate, a solvent such as terpineol, butyl carbitol, and butyl carbitol acetate, and other various dispersants, activators, plasticizers, and the like. Any one of them is appropriately selected according to the purpose. The amount of vehicle added is 10 to 10 in the paste.
It is preferably about 20% by weight.

It is preferable to form such a conductor paste so that the thickness after firing is about 5 to 20 μm, particularly about 8 to 150 μm. The film formation method may be a known screen printing method, transfer method, or the like. The wiring width of the internal wiring patterns other than the large area conductor pattern is 100 to 2
It is about 00 μm.

In the first aspect, the green sheet forming the pattern of the conductor paste contains glass and an oxide refractory ceramic as an insulating material. Examples of oxide refractory ceramics include Al ₂ O ₃ and R ₂ Ti ₂ O.
₇ (R is one or more of the lanthanide elements), Ca ₂ Nb ₂
O ₇ , MgTiO ₃ , SrZrO ₃ , TiO ₂ , SnO
₂・ TiO ₂ , ZrTiO ₄ , Ba ₂ Ti ₉ O ₂₀ , Sr
₂ Nb ₂ O ₇ , CaTiO ₃ , SrTiO ₃ , SrSn
One or more of O _{3 and the} like can be mentioned. In this case, the oxide used may have a composition that is slightly deviated from the stoichiometric composition, or may be a mixture with a deviated composition or a mixture of deviated compositions with each other.

The content of the oxide ceramic in the green sheet is preferably 20 to 40% by weight. If it is too large, the sinterability will deteriorate. On the other hand, if the amount is too small, the dielectric strength of the dielectric substrate will decrease. The average particle size of the oxide ceramic powder is preferably about 0.5 to 3 μm. If the average particle size is too small, it becomes difficult to form a sheet, and if it is too large, the strength becomes insufficient.

The glass powder has a softening point of 700-80.
It is preferable to use glass at about 0 ° C. If the softening point is too high, firing at a suitable temperature will be difficult, and if the softening point is too low, the binder will be hard to come off at the time of forming the sheet, resulting in a problem of insulation.

The composition of the glass powder to be used is not particularly limited, but the following composition is preferable from the viewpoint that a high-strength green sheet can be obtained at a firing temperature within the above range.

SiO ₂ : 50 to 70% by weight Al ₂ O ₃ : 6 to 10% by weight One or more alkaline earth metal oxides: 18 to 30% by weight B ₂ O ₃ :: 0 to 5% by weight

As the alkaline earth metal oxide, Sr
It is preferable to use one or more of O, CaO and MgO in combination, especially the above three.

The average particle size of the glass is not particularly limited, but usually one having a particle size of about 1 to 3 μm is used in consideration of moldability and the like. The content of glass in the green sheet is 40-60
It is preferably set to wt%. If the content is too small, the sinterability will deteriorate, and if it is too large, the electro-deposition strength will decrease.

As the insulating material, it is possible to use crystallized glass in which fine crystals are precipitated by heat treatment. In this case, anorthite (CaAl ₂ Si ₂ O ₈ ), Sergian (BaAl ₂ Si ₂ O ₈ ), nepheline (NaAl
SiO ₄ ), sufen (CaTiSiO ₅ ), cordierite (Mg ₂ Al ₂ Si ₅ O ₁₅ ), spodumene (L
A glass composition that deposits a silicate such as iAlSi ₂ O ₆ ) or an aluminosilicate is used.

Such a dielectric material is made into a slurry by adding a vehicle before sintering. As the vehicle, a binder such as ethyl cellulose, polyvinyl butyral, methacrylic resin, butyl methacrylate, terpineol, butyl carbitol, butyl carbitol acetate, acetate, toluene, alcohol, xylene and other solvents, various other dispersants, activators, plasticizers Examples thereof include agents, and any of these is appropriately selected according to the purpose. The amount of vehicle added is 6 with respect to the total amount of oxide ceramics and glass or 100 parts by weight of crystallized glass.
It is preferably about 5 to 85% by weight.

The multilayer wiring board of the present invention is manufactured as follows. First, the above-mentioned conductor paste is prepared.
At the same time, using the above-mentioned slurry, a predetermined number of green sheets of insulating material are produced by, for example, the doctor blade method. Next, a through hole is formed on the green sheet by using a punching machine or a die press, and then,
The conductor paste is printed on each green sheet by, for example, a screen printing method to form a predetermined conductor pattern and fill the through holes. In such a case, usually, a pattern in which a plurality of patterns for each substrate are arranged in an array is formed on a large-sized green sheet.

Next, the green sheets are superposed on each other, and hot press (about 40 to 120 ° C., 50 to 1000 Kgf / cm ² ) is added to form a green sheet laminate, and debinding process and formation of grooves for cutting are carried out. .. After that, the laminate of the green sheets is fired and integrated in normal air at the above temperature. Then, this is formed into a normal chip to obtain a multilayer wiring board. Then, print the external conductor paste if necessary,
The outer conductor is formed by firing.

In such a case, when screen printing or the like is performed on the green sheet, the pattern of the conductor paste is formed on the surface of the green sheet while the green sheet is supported by the carrier film. After peeling from the carrier film, the front and back directions of the green sheets are laminated so that the front surface and the back surface on the carrier film side are in contact with each other. This makes it unnecessary to manage the front and back of the sheet, which is extremely advantageous in mass production. Further, the setter contamination due to Ag is also eliminated.

The firing is performed by placing the laminate on a setter. In this case, during firing, the main surface 15 side on which the large-area conductor pattern 5 is located at 0.1t to 0.4t is placed on the setter side. Therefore, when firing, the capacitor portion 6
As long as the large-area conductor pattern 5 such as is located below the center, the stacking order at the time of stacking may be such that the capacitor portion 6 is located above. In this way, a defect-free substrate can be obtained without the need for a load plate even when high-speed binder removal and temperature increase are performed.

It should be noted that the firing may be carried out by holding in air at the above firing temperature for 5 minutes to 15 minutes, and the rate of temperature rise in the binder removal step is 8 to 15 ° C./minute and other temperature rises. The speed may be about 15 to 20 ° C./minute.

[0055]

EXAMPLES The present invention will be described in more detail with reference to specific examples of the present invention. Example 1 92.7% by weight of silver powder having a purity of 99.9% and an average particle size of 1 μm, 0.94% by weight of spherical Pd powder having an average particle size of 1 μm and 6.4% by weight of glass powder were prepared. As glass powder,
SiO _2: 53.05 wt%, SrO: 36.04 wt%, Al ₂ O _3: 10.91 average particle diameter of 1 weight percent of the composition
The one with μm was used. The softening point of this glass is 845 ° C. The vehicle was added to these mixtures, and the mixture was kneaded with a three-roll mill to obtain an internal conductor paste.

Separately, 60% by weight of glass particles and A
An insulating material containing 40% by weight of 1 ₂ O ₃ particles was prepared. Then, a vehicle was added to this insulating material and mixed by a ball mill to form a slurry to obtain a slurry. The composition of the glass particles is as follows: SiO ₂ : 62% by weight, Al ₂ O ₃ : 8% by weight, B
₂ O ₃ : 4 wt%, SrO: 19 wt%, CaO: 4 wt%, MgO: 3 wt%, and the softening point was 815 ° C.

Using this slurry, two kinds of green sheets having a size of 65 mm × 56 mm and a thickness of 70 μm and 180 μm were prepared by a doctor blade method. Of the green sheets, a total of 11 sheets, each having a thickness of 180 μm and one having a thickness of 70 μm, were used to form a laminated body for a multilayer wiring board with a built-in capacitor. More specifically, 10 green sheets with a thickness of 180 μm were prepared, and the pattern width after sintering was 100 μm on the surface of 8 of them, and the pattern area meter was 15% of the main surface area of the substrate. An internal wiring pattern was formed. In addition, one of them was not printed. In addition, one of these and the one with a thickness of 70 μm have
The large area conductor pattern for the capacitor electrodes 61 and 65 as shown in FIG. 6 was formed so that the area thereof would be 60% of the area of the main surface of the substrate after firing into chips. The thickness of each conductor pattern after sintering was 12 μm.

Then, among the large area conductor pattern carrying green sheets, one having a thickness of 180 μm at the bottom and one having a thickness of 70 μm at the top is laminated to form a capacitor section, and a total of eight 180 μm-thick internal wiring pattern carriers are carried. An unprinted 180 μm thick green sheet was laminated and integrated as the uppermost layer by interposing it at a predetermined position between the green sheets. At this time, as a matter of course, the front and back of each green sheet were aligned and laminated.

As a result, samples C to I were obtained in which a laminate having a built-in capacitor portion formed of a green sheet having a thickness of 70 μm was formed. Table 1 shows samples C to I.
The stacking position of the 70 μm thick green sheet of the capacitor part in FIG. The upper and lower conductor patterns were connected by predetermined through holes.

Separately from this, a total of nine 180 μm-thick internal wiring pattern-carrying green sheets were laminated, and sample B was obtained by laminating the above capacitor portion. Also,
Sample A with no capacitor part, by stacking a total of 10 180 μm thick green sheets carrying internal wiring patterns on top of the unprinted 180 μm thick green sheets
Also made. Furthermore, the two large-area conductor pattern-carrying green sheets each have a thickness of 70 μm, and these are stacked on top of each other.
Sample J was prepared by stacking a thick green sheet and an uppermost unprinted 180 μm thick green sheet.

After the laminated body samples A to J were produced in this manner, the laminated body samples A to J were placed so that the lowermost layer was in contact with the setter, and fired in the air. The firing temperature program is as follows.

100 to 150 ° C. 9 minutes 150 to 350 ° C. 15 minutes 350 to 700 ° C. 15 minutes 700 to 900 ° C. 15 minutes 900 ° C. 12 minutes 900 ° C. to room temperature 30 minutes

The thickness of samples B to C after firing was 1.45.
mm, and the lateral dimension of each sample was 60 mm.
Each sample was placed on a flat plate as it was, and the warpage of the substrate was measured. The warpage amount a is as shown in FIG.
In the case where the substrate is warped downward, it is a value obtained by subtracting the substrate thickness t from the distance a at the upper end μm of the edge from the substrate mounting surface. In addition, the downward convex is a positive sign, and the upward convex is a negative sign.
Table 1 shows the average warpage amount a of 20 samples in total.

Next, each sample was chipped to obtain a multilayer wiring board. The state of occurrence of internal cracks on the end surface of each substrate was observed with an optical microscope. Table 1 shows how many samples per 100 substrate samples had internal cracks.

The average lower surface position of the lower large-area conductor pattern and the average upper surface position of the upper large-area conductor pattern on each substrate were measured. The results are shown in Table 1.

[0066]

[Table 1]

From the results shown in Table 1, the effect of the present invention is clear.

Example 2 Insulating materials were SiO ₂ 35 wt%, CaO 6 wt%, S
rO 8wt%, Al ₂ O ₃ 12wt%, ZrO ₂ 10w
Each sample was produced in the same manner as in Example 1 except that the crystallized glass having the composition of t%, PbO 26%, and B ₂ O ₃ 3 wt% was used. The results are shown in Table 2.

[0069]

[Table 2]

From the results shown in Table 2, the effect of the present invention is clear.

In Examples 1 and 2, the binder removal step time of 150 to 350 ° C. was set to 15 during the firing program.
From 40 minutes to 40 minutes, the rate of crack occurrence was 0/100 in each sample, and the warpage amount a was also half or less.

[0072]

According to the present invention, it is possible to obtain a multi-layer wiring board having a very small warpage and a small number of cracks and peelings in a short baking time.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a multilayer wiring board of the present invention.

FIG. 2 is a front view showing a method for measuring a warp amount of a multilayer wiring board.

FIG. 3 is a diagram for explaining a decomposition state of a binder resin when firing a multilayer wiring board.

[Explanation of symbols]

 1 Multilayer Wiring Board 2 Insulating Layer 3 Conductor Pattern 4 Large Area Conductor Pattern 5 Internal Wiring Pattern 6 Capacitor Section 61, 65 Capacitor Electrode

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[Procedure amendment]

[Submission date] May 18, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (7)

[Claims] 1. A multilayer wiring board in which a conductor material pattern is formed on a green sheet of an insulating material, laminated, and fired at 1000 ° C. or less to form a conductor pattern between a plurality of insulating layers. In addition to having an internal wiring pattern and a large-area conductor pattern wider than that, the main component is Ag, and the large-area conductor pattern is formed from one main surface of the multilayer wiring board to a total thickness t of 0.1 t A multilayer wiring board provided at a position of 0.4t. 2. The large area pattern is formed from 0.10t to 0.
The multilayer wiring board according to claim 1, which is provided at a position of 35t. 3. The large area conductor pattern occupies 30% or more of the area of the main surface.
Multi-layer wiring board. 4. The multilayer wiring board according to claim 1, wherein the large-area conductor pattern is a plurality of capacitor electrode patterns formed on two or more insulating layers. 5. The insulating material contains glass powder and refractory ceramic powder, or contains crystallized glass powder.
Any of the multilayer wiring board. 6. In manufacturing the multilayer wiring board according to claim 1, the patterns are formed on the front surface side of each green sheet, and the green sheets are laminated so that the front surface and the back surface of each green sheet are in contact with each other. A method for manufacturing a multilayer wiring board, which is baked by firing. 7. The method of manufacturing a multilayer wiring board according to claim 6, wherein the large-area pattern is fired so as to be located below the center.