JPH0837372A - Production process of ceramic multilayer wiring board - Google Patents

Abstract

PURPOSE:To avoid forming any irregular face or warp of a laminate and form a fine and precise wiring patterns on the laminate by repeating a compression bonding step, adhering step, recess-forming step, conductor paste charging step and eliminating step, at least once. CONSTITUTION:The title method comprises steps of compression-forming a green sheet 14 having via-holes 12 to a ceramic base board 11, applying a dry film resist 15 to the sheet 14, forming recesses 18 in the form of a conductor pattern on the resist 15, and charging a conductor paste 19 into the recesses 18 and via-holes 12. These steps are repeated, at least once. Thus, the green sheets 14 to be stacked have a softness enough and hence neither irregular face nor uncharged part is formed in a laminate and no warp is caused. Thus, a fine multilayer wiring pattern is formed with a high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ceramic multilayer wiring board, and more particularly to a method for manufacturing a ceramic multilayer wiring board for mounting semiconductor LSIs, chip components, etc. and interconnecting them.

[0002]

2. Description of the Related Art In recent years, electronic devices have become smaller, higher in density, and operated at a higher speed, and there is now a demand for further size reduction. And to meet these demands, recently, multi-chip module (MCM)
The adoption of is starting to be considered. The MCM is one in which a plurality of bare chips (bare LSI that is not packaged) are mounted on a multilayer wiring board on which high-density wiring is formed. This MCM depends on the structure and material of the wiring board.
It is roughly classified into three types, ML, MCM-C, and MCM-D.

The MCM-L uses a glass / epoxy type printed wiring board as a substrate and can be produced at a low cost, but since the wiring area increases due to the presence of through via holes, the density can be increased. It has a problem that it does not exist, and is used in a low speed region (operating frequency is about 50 MHz). MCM-C uses ceramics for the substrate and has a wiring layer formed on it by the thick film method, and can be produced at a moderate cost, but due to the limitation of the wiring pitch due to the thick film technology. There is a limit to high density, medium speed range (operating frequency is 50 to 100MHz)
Used in. MCM-D uses polyimide as an insulating layer and has high-density wiring formed by a thin film process on a semiconductor such as a silicon substrate, and can be used in a high-speed region (operating frequency exceeding 100 MHz). it can. However, MCM-D has a problem that the number of steps in the thin film forming step is larger than that of other methods, and the manufacturing cost is high because the thin film forming apparatus is expensive.

Therefore, it is the MCM-C that is currently experimentally mounted on consumer electronic devices such as engineering workstations.

[0005]

In recent years, consumer electronic devices have been required to be used in a region where the operating frequency exceeds 100 MHz. However, as described above, the MCM-D is expensive and difficult to use in consumer electronic devices, while the MCM-D is difficult to use.
C cannot improve the degree of integration due to the limit of the wiring pitch, and is difficult to use in the high speed region. That is, the current M
According to the CM-C wiring rule, the wiring width is 100 μm, the wiring interval is about 100 μm, and the operating frequency is 100 μm.
In the high-speed region exceeding 10 μm, it is necessary to further reduce the wiring width and wiring interval.

Usually, the ceramic multilayer wiring board used as the MCM-C is manufactured by applying and printing a conductor pattern on a green sheet by a screen printing method, laminating the green sheets having these conductor patterns, and firing. However, since the mesh screen used for screen printing has a limit in mesh aperture ratio,
There is a problem that printing failure (bleeding, blurring, etc.) occurs in the conductor paste when printing the wiring rule of the order of 100 μm or less. Also,
After the conductor paste is applied and printed on the green sheet, the green sheet is heated in order to dry the conductor paste, but the heat treatment sometimes causes the green sheet to shrink. For this reason, there is a problem that the dimensional accuracy of the conductor pattern is lowered and a positional deviation occurs when the green sheets are stacked.

When filling the via hole formed in the green sheet with the conductor paste, the green sheet is placed on a base plate of a screen printing machine, and the conductor paste is filled into the inside of the via hole by a screen printing method. However, when the green sheet is removed from the base plate after filling the conductor paste, the conductor paste filled in the via holes adheres to the base plate, which causes a problem that the conductor paste is not filled inside the via holes.

Further, when a multilayer laminate formed by stacking green sheets on which conductor patterns are formed is fired, volume shrinkage occurs. At that time, the shrinkage rate varies from place to place by about ± 0.3%. There is also a problem that the accuracy of the wiring pattern is deteriorated because "warping" occurs on the substrate after firing due to the difference in shrinkage between the ceramics in the green sheet and the metal which is a conductor.

Therefore, a method of using a fired ceramics substrate and alternately printing a thick film conductor and an insulating paste on the ceramics substrate and firing the paste has been attempted. There is a problem in that it is not possible to form a precise wiring layer because unevenness occurs in the insulating layer laminated on the wiring layer and the unevenness increases as the wiring layers are stacked.

The present invention has been made in view of the above problems, and has no unevenness or warpage in the laminated body, no breaks or unfilled portions are formed therein, and a fine and precise wiring pattern is formed in multiple steps. It is an object of the present invention to provide a method for manufacturing a ceramic multilayer wiring board that can be formed.

[0011]

In order to achieve the above object, a method of manufacturing a ceramic multilayer wiring board according to the present invention comprises a pressure bonding step of pressure bonding a green sheet having via holes formed on the ceramic substrate, and the green sheet. An adhering step of adhering a dry film resist thereon, a recess forming step of forming a conductor pattern-shaped recess in the dry film resist, a conductor paste filling step of filling a conductor paste into the recess and the via hole, and the dry film It is characterized by repeating the erasing step of erasing the resist at least once or more (1).

The method for manufacturing a ceramic multilayer wiring board according to the present invention comprises a green sheet forming step of forming a green sheet on a dry film resist, a via hole forming step of forming a via hole in the green sheet, and the dry film resist. With the via hole facing upwards, a pressure bonding step of pressure bonding the green sheet with the via hole formed on the ceramic substrate, a recess forming step of forming a conductive pattern-shaped recess in the dry film resist, and a conductive paste filling the recess and the via hole. The step of filling the conductive paste and the step of eliminating the dry film resist are repeated at least once (2).

The method for manufacturing a ceramic multilayer wiring board according to the present invention comprises a pressure bonding step of pressure bonding a green sheet having via holes formed on the ceramic substrate, and a photo-resist in which the green sheet is filled with liquid photoresist and dried. A resist layer forming step, a recess forming step of forming a conductor pattern-shaped recess in the photoresist layer, and a conductor paste filling step of filling a conductor paste into the recess,
The erasing step of erasing the photoresist layer is repeated at least once (3).

The method (1) to (3) for manufacturing a ceramic multilayer wiring board according to the present invention will be described in detail below with reference to the drawings. Hereinafter, a method (1) for manufacturing the ceramic multilayer wiring board will be referred to as a first manufacturing method, a method (2) for manufacturing the ceramic multilayer wiring board will be referred to as a second manufacturing method, and a method (3) for manufacturing the ceramic multilayer wiring board will be described. Also referred to as the third manufacturing method.

First, the first manufacturing method according to the present invention will be described. 1A to 1I are cross-sectional views schematically showing each manufacturing step in the first manufacturing method.

In this method, first, as a crimping step,
The green sheet 14 having the via holes 12 formed thereon is pressure-bonded onto the ceramic substrate 11 (FIG. 1A).

Ceramic substrate 11 used in the present invention
Is not particularly limited as long as it can be used as a wiring substrate, and specific examples thereof include, for example, an alumina ceramics substrate, a mullite ceramics substrate, a glass ceramics substrate, an aluminum nitride ceramics substrate or the like which is usually used as a ceramics substrate. Is mentioned. The ceramic substrate 11 may be a substrate in which wiring or the like is formed inside or on the surface thereof.

The green sheet 14 is made of ceramic particles or glass particles that are usually used, for example, 60 to 70 wt% of particles of alumina, mullite, cordierite, aluminum nitride, silicon nitride, borosilicate glass, butyral resin, acrylic resin, or the like. Plastic resin (binder) 5-1
0 wt%, toluene, xylene, i-butanol, n-
It is composed of 15 to 20 wt% of a solvent such as butanol and 2 to 10 wt% of a plasticizer such as dioctyl phthalate (DOP) and dibutyl phthalate (DBP). The green sheet 14 can be manufactured by a known method. Examples of the method include a method of preparing a slurry having the above composition and then forming a green sheet 14 on a film base material 13 made of a resin having flexibility such as polyester and polyethylene by a doctor blade method or the like. . Since the green sheet 14 contains a resin binder and a plasticizer, it has shape retention and flexibility. The thickness of this green sheet 14 is usually 10 to 10.
It is about 400 μm.

As a method of forming the via hole 12 in the green sheet 14, there is a method which is usually used, that is, a method of forming a through hole by a punching method.
When punching, the method of forming the through holes at the same time in the green sheet 14 existing on the film base material 13 and the film base material 13 without peeling the film base material 13 expands and contracts the green sheet 14. Is not generated, which is preferable.

The green sheet 14 having the via holes 12 thus formed is pressure-bonded to the ceramic substrate 11, and the pressure-bonding method is preferably thermocompression bonding. The conditions for thermocompression bonding are a heating temperature of 80 to 120 ° C. and a pressure of 5
It is preferably about 30 kg / cm ² , and the thermocompression bonding time is about 10 seconds to 1 minute. At the time of pressure bonding, the film base material 13 and the green sheet 14 are not separated from each other, and the film base material 13 is attached to the ceramic substrate 1 with the film base material 13 facing upward.
It is preferable to adopt a method of crimping to No. 1 because expansion and contraction of the green sheet 14 does not occur. Further, a method of placing a rubber plate on the green sheet 14 and crimping the ceramic substrate 11 has some warpage or the like. Even in the case of doing so, there is no risk of damaging the ceramic substrate 11, which is preferable.

The positioning of the green sheet 14 at the time of pressure bonding is performed by forming a plurality of positioning marks 11a on the ceramic substrate 11 in advance by screen printing or the like, while the green sheet 14 is pierced for positioning. A hole is formed in advance, and when the green sheet 14 is pressure-bonded, the green sheet 14 is positioned so that the alignment mark 11a on the ceramic substrate 11 is located in the through hole formed in the green sheet 14. It may be placed on top and thermocompression bonded.

After that, the film substrate 13 is peeled off from the green sheet 14 (FIG. 1 (b)). In order to improve the releasability, the film base material 13 may be coated with silicon oil before forming the green sheet 14.

Next, as a bonding step, the green sheet 1
A dry film resist 15 is adhered onto the surface 4 (see FIG. 1).
(C)).

As the dry film resist 15, a well-known negative type resist can be used, and specific examples thereof include Liston manufactured by DuPont and Dialon manufactured by Mitsubishi Rayon. The thickness of the dry film resist 15 is preferably in the range of 15 to 50 μm.
If the thickness of the dry film resist 15 is less than 15 μm, it becomes difficult to fill the conductive paste in the subsequent step,
On the other hand, if the thickness exceeds 50 μm, the resolution is lowered.
As a method for adhering the dry film resist 15, it is preferable to adopt a thermocompression bonding method. The conditions for thermocompression bonding are a heating temperature of 8
0 to 110 ° C. and a pressure of 1 to 3 kg / cm ² are preferable.

Next, as a recess forming step, a conductive pattern-shaped recess 18 is formed in the dry film resist 15. In this case, the portion of the dry film resist 15 other than the conductor pattern is irradiated with the ultraviolet rays 17 through the photomask 16 designed so that the ultraviolet rays 17 are exposed (FIG. 1 (d)), and then the development treatment is performed. Thus, the conductor pattern-shaped recesses 18 are formed on the ceramic substrate 11 (FIG. 1E).

The conditions of the exposure treatment with the ultraviolet rays 17 are not particularly limited, but the exposure amount is usually preferably ²⁰ to 50 mJ / cm ² . If the exposure dose is less than 20 mJ / cm ² , it is difficult to completely form the recess 18 reaching the surface of the ceramic substrate 11 by development. On the other hand, if the exposure dose exceeds 50 mJ / cm ² , overexposure occurs and the recess 18 is formed. This is not preferable because the cross-sectional shape of is an inverted trapezoid.

The conditions of the developing treatment are not particularly limited, and the developing treatment can be carried out by a commonly used method such as a spray method or an immersion rocking method. The developer is 0.
A 1 to 1.0 wt% sodium carbonate aqueous solution is preferred.

Next, as a conductor paste filling step, the conductor paste 19 is filled in the conductor pattern-shaped recesses 18 (wiring portion and via cover portion) and the via holes 12 (FIG. 1).
(F)).

Usually, the conductor paste 19 is composed of conductor powder, a solvent, and a resin (binder). As the material for the conductor powder, a known conductor material that is usually used for wiring of a substrate or the like can be used, and specific examples thereof include W, Mo-Mn, Au, Ag, Ag-Pd,
Cu, Ni, Pd, etc. are mentioned.

As the solvent for the conductor paste 19,
For example terpineol, dibutyl phthalate (DBP)
For example, a known solvent may be used.

The binder for the conductor paste 19 must be one that does not dissolve in the photoresist layer disappearing liquid used in the subsequent step. This is because after filling the concave portion 18 formed in the dry film resist 15 and the via hole 12 of the green sheet 14 with the conductor paste 19, the dry film resist 15 is brought into contact with a developing solution to dissolve it.
This is for preventing the conductor paste 19 from being dissolved in the photoresist layer disappearing liquid in the disappearing step. Since the photoresist layer disappearing liquid is usually an aqueous solution, the resin used for the conductor paste 19 needs to be a water-insoluble resin. Specific examples of the resin include ethyl cellulose, acrylic resin, methacrylic resin and the like.

For the above reasons, the conductor paste 19 used in the present invention contains, for example, the conductor powders 84 to 96.
2% by weight of the resin (binder) such as the acrylic resin
6 wt%, the solvent such as terpineol is 2 to 16 wt%
% Composition is preferred. The conductor paste 19 can be prepared by a known preparation method such as a method using a triple roll.

After firing, the conductor and the ceramic substrate 1
In order to improve the adhesiveness with 1, the inorganic powders such as glass, SiO ₂ and TiO ₂ are added to the conductive powder in an amount of 1 to 10
You may add wt.

In order to fill the recess 18 and the via hole 12 of the dry film resist with the conductor paste 19 having the above composition, a squeegee is used, and the conductor paste 19 is filled with the conductor paste 19.
It is preferable to adopt a method of filling by directly rubbing into No. 8. The material of the squeegee used in this case is preferably rubber or fluororesin. There may be some conductor paste 19 remaining on the surface of the dry film resist 15 other than the recesses 18, but in this case, the conductor paste 19 can be almost removed by scraping with a squeegee to which the conductor paste 19 is not attached. The film resist 15 is not damaged. Furthermore, when there is an extremely thin layer of the conductor paste 19 that cannot be removed even by the above-mentioned operation, after drying the conductor paste 19, a wrapping film (those having alumina having a particle size of 1 μm adhered as abrasive grains) is applied. It can be removed by polishing with. Also, the recess 1
When the filling failure of the conductor paste 19 occurs in 8 and in the via hole 12, the filling direction is set to 9 from the initial filling direction.
Completely filling can be done by changing 0 degree and filling again.

After the conductor paste 19 is filled, as a drying step, the ceramic substrate 11 that has undergone the above steps is subjected to heat treatment to volatilize the solvent and the like in the conductor paste 19. The heat treatment is preferably performed at about 90 to 120 ° C. for about 10 to 20 minutes.

Next, as a disappearing step, the conductor paste 19
The dry film resist 15 filled with is treated with a photoresist layer disappearing liquid to be dissolved, and the dry film resist 15 is disappeared (FIG. 1 (g)). The photoresist layer disappearing liquid dissolves the dry film resist 15,
Moreover, it is necessary that the resin used for the conductor paste 19, the resin used for the green sheet 14 and the ceramic substrate 11 are not dissolved. Examples of such a photoresist layer disappearing liquid include a 1 to 5 wt% sodium hydroxide aqueous solution and a potassium hydroxide aqueous solution.
If the concentration of the photoresist layer disappearing liquid is less than 1 wt%, the dissolution rate of the photoresist layer is slow, while if the concentration of the photoresist layer disappearing liquid exceeds 5 wt%, the ceramic substrate 11 may be dissolved. A stripping solution from a photoresist maker may be used as the photoresist layer disappearing solution.

Through the above-mentioned steps, the conductor pattern (via, via) of the conductor paste dried body 19 'is formed on the green sheet 14 attached to the ceramic substrate 11.
A via cover portion and a wiring portion) are formed. When this is fired, the organic components in the green sheet 14 and the conductor paste dried body 19 'are decomposed and disappeared, and the ceramic particles contained in the green sheet 14 and the conductor paste dried body 19' are contained. The metal conductor that is
A ceramic multilayer wiring board is manufactured, but usually, after forming a conductor pattern (hereinafter, referred to as a multilayer laminate) composed of a plurality of layers of green sheets 14 and conductor paste 19 on a ceramic substrate 11, a firing process is performed. To do.

In this case, the crimping step, the adhering step, the recess forming step and the conductor paste filling step,
And repeating the disappearing step a plurality of times, and laminating a plurality of layers of the green sheet 14 and the conductor pattern having the same shape on the green sheet 14 on which the conductor pattern made of the conductor paste dried body 19 is formed by the above-mentioned steps. , A multi-layer laminate is formed (FIG. 1 (i)).

In the second and subsequent crimping steps,
The green sheet 14 is attached to the green sheet 14 having the conductor pattern formed thereon by thermocompression bonding or the like (FIG. 1 (h)). Due to the thermocompression bonding, the green sheet 14 is filled in the portions (grooves) on the green sheet 14 where the conductor pattern is not formed, so that no gap is generated between the lower green sheet 14 and the upper green sheet 14. Absent.

After these steps are completed, the ceramic having the multilayer laminated body formed thereon is fired to complete the production of the ceramic multilayer wiring board. The firing conditions differ depending on the type of the conductor contained, but the atmosphere and temperature conditions in which the green sheet 14 and the metal conductor are sintered and firmly adhered to the ceramic substrate 11 are preferable.

Next, the second manufacturing method (2) will be described. In this method, a dry film resist 15 is used instead of the film base material 13 used in forming the green sheet 14 in the first manufacturing method. Therefore, in the green sheet forming step, the green sheet 14 is formed on the dry film resist 15, and the green sheet 14 is pressure-bonded onto the ceramic substrate 11 without peeling the dry film resist 15 as it is. The crimping method may be the same as the first manufacturing method. Comparing this method with the first manufacturing method, it is not necessary to peel the film base material 13 from the green sheet 14, and the step of adhering the dry film resist 15 to the green sheet 14 can be omitted.

Thereafter, the recess forming step, the conductor paste filling step and the erasing step are performed in the same manner as the first manufacturing method, and the above steps are repeated a plurality of times if necessary. Since these methods have been described in detail in the first manufacturing method, detailed description thereof will be omitted here.

Next, the third manufacturing method (3) will be described. 2A to 2I are cross-sectional views schematically showing each manufacturing step in the third manufacturing method. In addition,
Since the process after (e) is the same as the first manufacturing method, the description thereof is omitted here.

In the third manufacturing method, first, a pressure bonding step is performed as in the first manufacturing method (see FIG. 2).
(A)) Then, the film base material 13 is peeled off (see FIG. 2).
(B)).

Next, as a photoresist layer forming step,
Apply a liquid photoresist to the green sheet 14,
Dry to form a photoresist layer 25 (FIG. 1).
(C)).

Examples of the coating method include a roll coater method, a bar coater method, a dipping method, a Wheeler method (spinner method) and the like. After applying a liquid photoresist on the green sheet 14 by these methods,
Put the ceramics substrate 11 in the oven for about 87-90.
Heat at 30 ° C for about 30-40 minutes to dry the photoresist,
Let it solidify. Through this step, the via holes 12 formed in the green sheet 14 are also filled with the photoresist,
Solidify. In the recess forming process of the next process, the via hole 12
It is necessary to completely remove the photoresist filled in the inside, and in this case, the negative type photoresist is preferable for the following reasons. That is, when a negative photoresist is used, since the conductor pattern forming portion is an unexposed portion, it is possible to perform ultraviolet exposure at an optimum exposure amount,
Dissolution with a developing solution is also easy. On the other hand, when a positive photoresist is used, since the conductor pattern portion must be used as a photosensitive portion, it is necessary to expose the inside of the via hole 12 as well, and therefore the exposure amount must be greatly increased. Therefore, accurate patterning becomes difficult. Examples of the negative photoresist include PMERN-H600 manufactured by Tokyo Ohka Kogyo Co., Ltd.

Next, as described above, an exposure process with ultraviolet rays 17 is performed using the photomask 16 designed so that the conductor pattern portion becomes an unexposed portion (FIG. 2).
(D)). The exposure amount by the ultraviolet rays 17 is usually 200 to 40
0 mJ / cm ² is preferable. The exposure dose is 200 mJ /
If it is less than cm ² , it is difficult to completely form the concave portion 18 reaching the surface of the lower layer by development, while if the exposure amount exceeds 400 mJ / cm ² , overexposure occurs and the sectional shape of the concave portion 18 is an inverted trapezoid. Is not preferable.

After that, a ceramic multilayer wiring board can be manufactured by performing the same steps under the same conditions as in the first manufacturing method.

[0049]

According to the method (1) for manufacturing a ceramic multilayer wiring board having the above structure, a pressure bonding step of pressure bonding a green sheet having via holes formed on the ceramic substrate,
An adhering step of adhering a dry film resist on the green sheet, a recess forming step of forming a conductor pattern-shaped recess in the dry film resist, and a conductor paste filling step of filling a conductor paste into the recess and the via hole, Since the erasing step of erasing the dry film resist is repeated at least one or more times, it is possible to form a highly precise and fine conductor pattern on the green sheet attached to the ceramic substrate by the pressure bonding step, the bonding step and the recess forming step. Of the green sheet fixed to the ceramic substrate by the conductor paste filling step is filled with the conductor paste with a good filling property, and the dry film resist is completely disappeared by the disappearing step and Only dried conductor paste remains Further, although the above steps are repeated at least once or more, since the laminated green sheets have flexibility, no unevenness or unfilled portion is generated in the multilayer laminate. Further, since the green sheet is fixed to the ceramic substrate, it does not shrink in the planar direction during firing and does not warp, so that a ceramic multilayer wiring substrate having a highly precise and fine multilayer wiring pattern is manufactured.

According to the method (2) for manufacturing a ceramic multilayer wiring board having the above structure, a green sheet forming step of forming a green sheet on the dry film resist, a via hole forming step of forming a via hole in the green sheet, A pressure-bonding step of pressure-bonding a green sheet having a via hole formed thereon to a ceramic substrate with the dry film resist on the upper side, a recess forming step of forming a conductive pattern-shaped recess in the dry film resist, and a conductor paste containing the recess and Since the conductor paste filling step of filling the via hole and the disappearing step of disappearing the dry film resist are repeated at least once or more, in addition to the function described in (1) above, the peeling step of the film base material and the dry film resist You can omit the bonding process. Readily ceramic multilayer wiring board is manufactured.

Further, according to the method for manufacturing a ceramic multilayer wiring board having the above structure, a pressure bonding step of pressure bonding a green sheet having a via hole formed on the ceramic substrate, and filling the green sheet with a liquid photoresist and drying it. A photoresist layer forming step, and a recess forming step of forming a conductive pattern-shaped recess in the photoresist layer,
Since the step of filling the concave portion with the conductor paste and the step of eliminating the photoresist layer are repeated at least once or more, the photoresist layer is easily formed on the green sheet by the liquid photoresist which is easy to handle. After that, a ceramic multilayer wiring board having a precise and fine multilayer wiring pattern is manufactured by the same process as the method described in (1) above.

[0052]

EXAMPLES AND COMPARATIVE EXAMPLES Examples and comparative examples of the method for manufacturing a ceramic multilayer wiring board according to the present invention will be described below.

Example 1 First, a green sheet having via holes with a diameter of 50 μm formed on an alumina ceramic substrate was thermocompression-bonded to a predetermined position while the film substrate was still attached. The conditions for thermocompression bonding are a heating temperature of 100 ° C. and a pressure of 2
kg / cm ^2, was dwell time of 30 seconds. The alignment of the green sheet was performed so that the alignment mark formed by screen printing on the alumina ceramic substrate and the through hole portion for alignment formed on the green sheet were aligned. When the green sheet was thermocompression-bonded, a rubber plate having a thickness of 2 mm was placed on the film base material and pressure-bonded. The green sheet is 60 wt% of alumina powder (average particle size 2 μm), and CaO-Al ₂ O ₃ -B.
₂ O ₃ -SiO ₂ glass powder (average particle size 4.2 μ
m) 100 parts by weight of mixed powder consisting of 40 wt%, 13 parts by weight of methacrylic acid ester resin as an organic resin binder, 5 parts by weight of DOP as a plasticizer, and 27 total of toluene and xylene (1: 1) as a solvent. What was added by weight was used. The green sheet had a thickness of 80 μm.

Next, the film substrate was peeled from the green sheet, and a dry film resist (liston 4713 manufactured by DuPont) having a thickness of 33 μm was laminated on the green sheet at a heating temperature of 105 ° C. and a pressure of 2 kg / cm ² . .

Next, the dry film resist was exposed to a dose of 30 mJ / through a photomask on which a conductor pattern having a wiring width of 50 μm and a line interval of 50 μm was formed.
An exposure treatment with an ultraviolet ray 14 was performed so that the cm ² was obtained.

Next, the alumina ceramics substrate that has undergone the above steps is dipped in a developing solution (solution temperature 30 ° C.) consisting of a 1.0 wt% sodium carbonate aqueous solution for 25 seconds to form the conductive pattern-shaped recesses in the positive photoresist layer 12. Formed.

Next, using a fluororesin squeegee, the conductor paste was rubbed into the recesses and filled.
This conductor paste is Ag powder (average particle size 2.0 μm).
m): 85 wt%, acrylic resin: 4 wt%, and terpineol: 11 wt%. When the conductor paste was defective in filling, the filling process was performed again.

Then, the alumina ceramics substrate that has undergone the above steps is put in an oven, and as a conductor paste drying treatment, a heat treatment is performed at 100 ° C. for 10 minutes to volatilize the solvent and bond the conductor paste to the green sheet or the alumina ceramics substrate. Let Then, the surface of the dry film resist was polished for about 10 seconds using a wrapping film (mesh # 4000) to remove excess conductor paste. In this step, the conductor paste was also filled inside the via holes formed in the green sheet.

Next, the alumina ceramics substrate which has undergone the above steps was immersed in a photoresist layer disappearing liquid consisting of a 3 wt% sodium hydroxide aqueous solution for 1 minute to eliminate the remaining dry film resist. As a result, the green sheet and the conductor-pattern dried conductor paste were left on the alumina ceramic substrate.

Then, as in the beginning, the green sheet having the via holes formed therein was thermocompression-bonded to a predetermined position with the film substrate attached. A green sheet having flexibility was bitten by thermocompression bonding in this pressure bonding step into the groove portion between the conductor paste dried bodies formed by the disappearance of the dry film resist in the previous step, and no void was formed.

Next, the above-described bonding step, recess forming step,
The multilayer paste was formed on the ceramic substrate by repeating the conductor paste filling step and the disappearing step four times.

Finally, the alumina ceramics substrate that has undergone the above steps is fired in the atmosphere at 900 ° C. for 10 minutes to decompose and eliminate the organic components in the dried green sheet and conductor paste, and at the same time, to remove the green sheet and the conductor. The powder was sintered and adhered to the alumina ceramics substrate to complete the production of the ceramic multilayer wiring substrate.

A cross-sectional structure of the manufactured ceramic multilayer wiring board was examined by a scanning electron microscope (SEM). As a result, a wiring having a wiring width of 50 μm and a wiring interval of 50 μm was formed inside, and a conductor layer was also formed in the via hole. It was densely formed. In addition, it was confirmed that the insulating layers formed from the green sheets had uniform thickness in each layer and were formed in parallel with each other. Further, it was confirmed that the LSI was actually mounted on the ceramic multilayer wiring board and that the LSI operates normally.

[Example 2] Example 1 as a film substrate
Using the dry film resist used in step 1, a green sheet was formed on the dry film resist, and a via hole was formed in the green sheet in the same manner as in Example 1.

Thereafter, as in Example 1, the bonding step, the recess forming step, the conductor paste filling step, and the disappearing step are repeated four times to form a multilayer laminate on the ceramic substrate, and the ceramic multilayer wiring substrate is baked. Manufactured. Since the dry film resist is used as the film base material, a peeling step of the film base material is not necessary, and the conductive film-like concave portions may be formed on the dry film resist as it is.

The manufactured ceramic multilayer wiring board was observed by SEM in the same manner as in Example 1, and it was confirmed that the ceramic multilayer wiring board having the same excellent characteristics as in Example 1 was formed. Moreover, it was confirmed that the LSI was actually mounted on the ceramic multilayer wiring board and that the LSI operates normally.

Example 3 A ceramic multilayer wiring board was manufactured in substantially the same manner as in Example 1 except that a liquid photoresist was used instead of the dry film resist and a photoresist layer was formed on the green sheet. If a liquid photoresist is used, the photoresist will be filled inside the via holes of the green sheet.
This portion also needs to be dissolved and removed in the disappearance step.
Therefore, the steps up to the disappearance step will be described below.

A liquid negative photoresist (PMER N-H600 manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied using a bar coater (winding mill No. 40), and it was applied at 70 ° C. for 30 minutes.
A 25 μm thick photoresist layer was formed on the green sheet by drying with warm air for a minute. A negative photoresist layer was also formed inside the via hole formed in the green sheet by the above process.

Then, the negative photoresist layer was exposed to a dose of 250 mJ through a photomask on which a conductor pattern having a line width of 50 μm and a line interval of 50 μm was formed.
An exposure treatment with ultraviolet rays 14 was performed so that the concentration became / cm ² .

Next, the alumina ceramics substrate that has undergone the above steps is dipped in a developing solution (solution temperature 30 ° C.) consisting of a 1.0 wt% sodium carbonate aqueous solution for 30 minutes to form the conductive pattern-shaped depressions in the negative photoresist layer. Formed. In this step, the negative photoresist layer formed inside the via hole of the green sheet was completely removed.
It was confirmed by observing the cross section by SEM. After this step, a ceramic multilayer wiring board was manufactured by performing the same steps as in Example 1 as described above.

The manufactured ceramic multilayer wiring board was observed by SEM in the same manner as in Example 1, and it was confirmed that a ceramic multilayer wiring board having the same excellent characteristics as in Example 1 was formed.

[Comparative Example 1] A green sheet was pressure-bonded onto an alumina ceramic substrate in the same manner as in Example 1.

Next, using the conductor paste used in Example 1, a conductor pattern was formed on the green sheet by a screen printing method, and dried under the same conditions as in Example 1.

Next, the step of pressing the green sheet again onto the green sheet having the conductor pattern made of the dried conductor paste and the step of printing the conductor paste are repeated 4 times in the same manner to form a laminated body on the alumina ceramic substrate. Then, firing was performed under the same conditions as in Example 1.

SEM observation of the manufactured ceramic multilayer wiring board was carried out in the same manner as in Example 1. As a result, a large number of broken wires, shorted wires, and unfilled conductors inside the via holes were observed. It was confirmed to exist.

[0076]

As described above in detail, in the method (1) for manufacturing a ceramic multilayer wiring board according to the present invention, a pressure bonding step of pressure bonding a green sheet having via holes formed on the ceramic substrate, and the green An adhering step of adhering a dry film resist on a sheet; a recess forming step of forming a conductor pattern-shaped recess in the dry film resist; a conductor paste filling step of filling a conductor paste into the recess and the via hole; Since the erasing step of erasing the film resist is repeated at least one or more times, highly accurate and fine conductor pattern-shaped concave portions are formed on the green sheet adhered to the ceramic substrate by the pressure bonding step, the bonding step and the concave portion forming step. Can be formed on the ceramic substrate by the conductor paste filling step. Can be filled with filling good conductor paste in a recess including a constant is green sheet via holes, completely abolished the dry film resist by the disappearance step is can be left only conductive paste dried body. Further, the above steps are repeated at least once, but since the laminated green sheets have flexibility,
It is possible to prevent the unevenness and the unfilled portion of the multilayer laminate from being generated. Further, since the green sheet is fixed to the ceramic substrate, it is possible to prevent the green sheet from shrinking or warping in the plane direction during firing, and as a result, a ceramic having a highly precise and fine multilayer wiring pattern. A multilayer wiring board can be manufactured.

In the method (2) for manufacturing a ceramic multilayer wiring board according to the present invention, a green sheet forming step of forming a green sheet on the dry film resist and a via hole forming step of forming a via hole in the green sheet. A pressure-bonding step of pressure-bonding the green sheet having via holes formed thereon to a ceramic substrate with the dry film resist facing upward; a recess forming step of forming a conductive pattern-shaped recess in the dry film resist; Since the conductive paste filling step of filling the concave portion and the via hole and the disappearing step of disappearing the dry film resist are repeated at least one or more times, in addition to the effect described in (1), a peeling step of the film base material and a dry film. The resist adhesion process can be omitted More easily it can be manufactured of ceramic multi-layer wiring board.

Further, in the method (3) for manufacturing a ceramic multilayer wiring board according to the present invention, a pressure bonding step of pressure bonding a green sheet having via holes formed on the ceramic substrate, and a liquid photoresist on the green sheet. Filling and drying a photoresist layer forming step, a recess forming step of forming a conductive pattern-like recess in the photoresist layer, a conductor paste filling step of filling a conductive paste into the recess, and the photoresist layer disappearing. Since the erasing step is repeated at least once, the photoresist layer is easily formed on the green sheet by the liquid photoresist which is easy to handle, and thereafter, the steps similar to the method described in (1) above are performed to obtain the same precision. Thus, it is possible to manufacture a ceramic multilayer wiring board having a fine multilayer wiring pattern.

[Brief description of drawings]

1A to 1I are cross-sectional views schematically showing each step in a method for manufacturing a ceramic multilayer wiring board according to the present invention (first manufacturing method).

2 (a) to (i) are cross-sectional views schematically showing each step in the method for manufacturing a ceramic multilayer wiring board according to the present invention (third manufacturing method).

[Explanation of symbols]

 11 Ceramics Substrate 12 Via Hole 14 Green Sheet 15 Dry Film Resist 18 Recess 19 Conductor Paste 25 Photoresist Layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Otomo 2701-1 Iwakura, East branch, Omine Town, Mine City, Yamaguchi Prefecture, Sumitomo Metal Ceramics Co., Ltd.

Claims (3)

[Claims] 1. A pressure-bonding step of pressure-bonding a green sheet on which a via hole is formed on a ceramic substrate, an adhesion step of bonding a dry film resist on the green sheet, and a conductive pattern-shaped concave portion on the dry film resist. A ceramic multi-layer wiring board characterized in that a step of forming a concave portion, a step of filling a conductive paste in the concave portion and the via hole, and a step of eliminating the dry film resist are repeated at least once or more. Production method. 2. A green sheet forming step of forming a green sheet on a dry film resist, and a via hole forming step of forming a via hole in the green sheet,
A pressure-bonding step of pressure-bonding a green sheet having a via hole formed thereon to a ceramic substrate with the dry film resist on the upper side, a recess forming step of forming a conductive pattern-shaped recess in the dry film resist, and a conductor paste containing the recess and A method for manufacturing a ceramic multilayer wiring board, comprising repeating a conductive paste filling step of filling the via hole and a disappearing step of removing the dry film resist at least once. 3. A pressure-bonding step of pressure-bonding a green sheet having a via hole formed on a ceramics substrate, a photoresist layer forming step of filling the green sheet with a liquid photoresist and drying the photoresist, and forming a photoresist layer on the photoresist layer. A recess forming step of forming a conductor pattern-shaped recess, a conductor paste filling step of filling the recess with a conductor paste,
A method of manufacturing a ceramic multilayer wiring board, characterized in that the step of erasing the photoresist layer is repeated at least once.