JP3351043B2 - Method for manufacturing multilayer ceramic substrate - Google Patents

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 for mounting semiconductor LSIs, chip components and the like and interconnecting them.

[0002]

2. Description of the Related Art In recent years, with the development of a low-temperature sintered glass / ceramic multilayer substrate, usable conductor materials include gold, silver, and silver.
Copper, palladium or mixtures thereof have been used. These metals have a lower conductor resistance than conventionally used tungsten, molybdenum, and the like, and can be used with safe equipment at low cost, and have a wide range of applications. However, the multilayer ceramic substrate generally undergoes shrinkage due to sintering during firing, and this shrinkage behaves differently depending on the substrate material used, green sheet composition, powder lot, and the like. This causes several problems in the fabrication of a multilayer substrate. First,
In order to form the uppermost layer wiring after firing the inner layer wiring in the production of the multilayer ceramic substrate as described above, if the shrinkage error of the substrate material is large, the uppermost layer wiring pattern and the inner layer electrode may have a dimensional error. Connection cannot be established. As a result, a land having an unnecessarily large area must be formed on the uppermost layer electrode portion so as to allow a shrinkage error in advance.
It cannot be used for circuits that require high-density wiring. In addition, a method is used in which several screen plates for the uppermost layer wiring are prepared in accordance with the shrinkage error and used according to the shrinkage ratio of the substrate. In this method, a large number of screen plates must be prepared, which is uneconomical.

On the other hand, if the uppermost layer wiring is performed simultaneously with the inner layer firing, a large land is not required. However, even with this simultaneous firing method, the shrinkage error of the substrate itself remains as it is, so that the cream solder printing at the time of the final component mounting is performed. In some cases, printing cannot be performed on a required portion due to the error.
Also, in component mounting, there is a shift from a predetermined component position.

The shrinkage of the multilayer substrate formed by the second green sheet laminating method differs depending on the film forming direction of the green sheet also in the width direction and the longitudinal direction. This also hinders the production of the ceramic multilayer substrate.

In order to minimize these shrinkage errors, the following methods are generally proposed and implemented. The first method is to use only the one in which the shrinkage error is within a predetermined specification. Although this method can obtain a desired high dimensional accuracy, the production cost is large because the production yield is extremely low. Does not fit current needs.
The second is a method for suppressing the shrinkage error while the absolute value of the shrinkage ratio of the substrate is large. In the manufacturing process, not only the management of the substrate material and the composition of the green sheet, but also the difference between the powder lots and the laminating conditions (press pressure). , Temperature), but the error in shrinkage is generally ±
It is said that there is about 0.5%, and it is a limit to suppress the shrinkage error any more. Third, the contraction error is suppressed by reducing the substrate contraction rate. This is a technique for suppressing the shrinkage of the substrate by bringing a porous sintered plate or a green sheet or the like made of a material that does not sinter at the firing temperature of the substrate into contact with both surfaces of the green sheet laminate and firing the green sheet. This is proposed by Japanese Patent Publication No. 62-260777. The structure and the manufacturing method will be described below with reference to FIG. In FIG. 2, 12
Is a glass / ceramic green sheet laminate, and 13 is a porous ceramic sintered plate. In the above configuration,
As shown in (a), the porous ceramic sintered plate 13 is arranged on both surfaces of the glass / ceramic green sheet laminate 12 and pressed. Next, as shown in (b), firing is performed at the firing temperature of the glass-ceramic material. In this way, shrinkage due to sintering of the glass-ceramic substrate is suppressed in the plane direction and occurs only in the thickness direction. Thereafter, as shown in (c), the porous ceramic sintered plate 1 remaining on both surfaces of the substrate was obtained.
3 is removed and the multilayer substrate 11 is manufactured. According to the method for manufacturing a multilayer ceramic substrate, a shrinkage in the planar direction is extremely small, and a shrinkage error is small, so that a substrate having high dimensional accuracy can be manufactured, which is extremely industrially effective.

[0006]

However, a problem has arisen in the manufacture of a multilayer ceramic substrate that suppresses shrinkage in the planar direction of the substrate and causes only shrinkage in the thickness direction. This is a problem that the pattern shrinkage due to the substrate and the electrode paste does not match during firing because the substrate shrinkage is suppressed. For this reason, a substrate crack occurs due to a difference in shrinkage behavior during firing at the lower surface portion where the electrode pattern and the substrate are in contact, or sintering of the electrode does not increase due to inhibition of sintering of the electrode pattern. Have a large conductor resistance value. Due to such problems, the multilayer ceramic substrate that suppresses the shrinkage in the plane direction of the substrate and only causes shrinkage in the thickness direction has high dimensional accuracy, but the reliability as a substrate is low, and the resistance value of the conductor is high. In addition, there is a restriction that it can be used only for a substrate having an extremely small circuit pattern which is not easily affected by an increase in the resistance value.

[0007]

According to the present invention, there is provided a green sheet comprising a low-temperature sintered glass / ceramic material, an organic binder and a plasticizer.
The electrode pattern is formed by using a metal conductor, wherein the low-temperature co-fired glass-ceramic material green sheet and another an electrode patterned green sheets were desired number laminate
On both sides of the first of the laminate of the green sheet made from the fee, before
Forming a second laminate by laminating green sheets of an inorganic composition that does not sinter at the firing temperature of the first laminate;
In the method of manufacturing a multilayer ceramic substrate for firing the second laminate, an electrode pattern shape using the metal conductor is provided.
To form a conductive pattern formed on a polymer film,
Transfer to green sheet made of ceramic material
The polymer pattern of the conductor pattern.
The film is formed on the polymer film by a metal conductor.
Is performed by plating after crimping
Things.

[0008]

According to the present invention, a multi-layer ceramic substrate which contracts only in the thickness direction during firing and does not shrink in the plane direction by performing the above-described steps is used to produce a substrate having a low conductor resistance value and high reliability. I do. Hereinafter, the operation of the present invention will be described.

That is, the present invention provides a method for producing a green sheet comprising a low-temperature sintered glass / ceramic material, an organic binder and a plasticizer, forming an electrode pattern using a metal conductor, and forming another electrode pattern on the green sheet. the already formed green sheet on both sides of the first stack of green sheets made of the low-temperature co-fired glass-ceramic materials desired number laminating, the green with an inorganic composition that is not sintered at the firing temperature of the first laminate In the method for manufacturing a multilayer ceramic substrate in which a sheet is laminated to form a second laminate and the second laminate is fired, the metal conductor is used.
The electrode pattern is formed by a conductor formed on a polymer film.
The pattern is made of a green ceramic
To the conductor pattern.
The formation of the polymer film on the polymer film
After the metal conductor is crimped on the
It is. In this method of manufacturing a substrate, the glass-ceramic layer is sandwiched between the non-sintered materials laminated on both surfaces during firing of the substrate, so that shrinkage in the planar direction is prevented,
Shrinkage occurs only in the thickness direction. Rather than conductive material such as paste to sinter the metal powder during firing to its as an electrode material, a metal having a small dimensional change during substrate sintering
Conductors can be used without worrying about substrate cracking
In the case of a metal conductor, it is effective as a conductor since the resistance value is small . As the metal conductor, a conductor mainly containing one of Ag, Ag-Pd, Ag-Pt, and Cu as a conductor material is used. At this time, to roughen the surface of the metal conductor to improve the adhesion between the metal conductor and the glass-ceramic layer, to prevent peeling of a metal conductor and glass-ceramic layers during substrate sintering including removal of the organic binder. further,
After using a metal conductor containing CuO as a main component as a conductor and removing the organic binder of the substrate by heat treatment in an air atmosphere, for example, CuO is reduced to Cu in a reducing atmosphere such as a hydrogen atmosphere, and a nitrogen atmosphere is used. Fire in a neutral atmosphere. This method makes it easy to control the atmosphere for firing the substrate.

[0010] The formation of the conductor pattern by the metal conductor is as follows.
A conductor foil on a polymer film having a thermoplastic resin layer,
Thermocompression bonding at a temperature near the melting point of the thermoplastic resin, and then forming a conductor pattern by plating, or forming a conductor pattern on the film by vapor deposition and forming a glass / ceramic green sheet at a temperature near the melting point of the thermoplastic resin Heat transfer. The method of forming a conductor pattern on a polymer film is generally the same as the method of forming a conductor pattern on a glass / epoxy substrate, and can be easily performed with existing equipment. The conductor patterns formed by metal conductors, react with the conductive paste during firing, do not adhere, and sintering pre ceramic reaction, Al ₂ O ₃ as a layer which does not adhere, MgO, ZrO
_2. A conductor pattern formed by printing and firing a paste on a conductor on a sintered ceramic substrate having a powder layer containing at least one or more of MgO, SiO ₂ , AlN, BN, and TiO _2. It is also possible by transferring to a sheet. In this method, no environmental protection equipment is required because a large amount of liquid such as a plating solution is not used.

The firing of the glass-ceramic laminate is usually performed at a temperature in the range of 800 ° C. to 1000 ° C. When a copper electrode or a silver electrode is used, the heat treatment is performed at 900 ° C. Also glass
The inorganic components of the inorganic composition green sheet that do not sinter at the firing temperature of the ceramic low-temperature sintering substrate material include Al ₂ O ₃ ,
It contains at least one or more of MgO, ZrO ₂ , TiO ₂ , BeO, and BN. Al ₂ O ₃ is most effective for a low-temperature sintering substrate material performed at a firing temperature of 900 ° C.

When the glass / ceramic laminate is fired by pressing the glass / ceramic laminate at the time of firing, a dense sintered body can be obtained by further promoting the sinterability in the thickness direction.

[0013]

An embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) In FIG. 1, a glass-ceramic green sheet 1 shown in FIG. 1A is made of a low-temperature sintered glass-ceramic material, for example, lead borosilicate glass powder as an inorganic component and Al ₂ as a ceramic material. Mixing of a 50 to 50 weight ratio of O ₃ powder (MLS-19 manufactured by NEC Corporation), polyvinyl butyral as an organic binder, ヂ -n-butyl phthalate as a plasticizer, and toluene and isopropyl alcohol as a solvent Liquid (30:70 weight ratio) mixed into a slurry,
This slurry was formed into a sheet by a doctor blade method.
Next, as shown in (b), using only Al ₂ O ₃ (AL-41 manufactured by Sumitomo Aluminum Co., Ltd., average particle size: 1.9 μm) powder that does not cause sintering when the substrate is fired, the same as the glass ceramic green sheet. A prepared by the same method with the composition
l ₂ O ₃ green sheet 2 was used. The thickness of each of the glass / ceramic green sheet 1 and the Al ₂ O ₃ green sheet 2 is about 200 μm. As shown in (c),
The via conductor 3 was formed on the glass / ceramic green sheet 1 by a screen printing method, and the glass / ceramic green sheet 4 on which the via conductor was formed was formed. The conductive paste for vias is a glass frit (GA manufactured by NEC Corporation) for obtaining adhesive strength to Ag powder (average particle size: 1 μm).
-9 glass powder, average particle size of 2.5 μm) and 5 wt% of glass-ceramic powder were added as an inorganic component, and ethyl cellulose as an organic binder was added together with a vehicle dissolved in terpineol to obtain 3
What was mixed by a step roll so that it might become moderate viscosity was used.

On the other hand, as shown in FIG. 1D, a Cu foil 7 is placed on a polymer film 6 formed of polyacrylonitrile as a thermoplastic resin layer 5 at a temperature of 80 ° C. and a pressure of 200 kg.
/ Cm ² , and a conductive pattern 8 was formed by plating, and then oxidized to CuO. As shown in (e), the glass / ceramic green sheet is formed by applying heat and pressure in the plane direction so that the conductor pattern 8 formed on the polymer film 6 is in contact with the glass / ceramic green sheet 4 on which the via conductor is formed. Conductor pattern 8 on top
Was transcribed. The transfer conditions are as follows: temperature is 80 ° C., pressure is 10
It was 0 kg / cm ² . As shown in (f), a predetermined number of the glass / ceramic green sheets on which the conductor patterns were formed were stacked, and the Al ₂ O ₃ green sheets 2 were stacked on both surfaces to form a laminate 9. The laminate 9 was formed by thermocompression bonding in this state. The thermocompression bonding conditions were a temperature of 80 ° C. and a pressure of 200 kg / cm ² .

Next, the laminate 9 is placed in an air atmosphere at 500 ° C.
Decomposes and removes the organic binder in a hydrogen atmosphere at 200 ° C
Reduces CuO to Cu. Further, firing is performed in a nitrogen atmosphere. The conditions were firing at 900 ° C. in air injection for 1 hour in a belt furnace. (The holding time at 900 ° C. is about 12 minutes.) At this time, in order to assist the warpage of the substrate and the shrinkage of the sintering in the thickness direction, an Al ₂ O ₃ sintered substrate was placed and the firing was performed.

The unfired A
Because of the presence of the l ₂ O ₃ layer, ultrasonic cleaning was performed in a butyl acetate solvent, and the Al ₂ O ₃ layer could be removed cleanly. When the shrinkage ratio of the fired substrate was measured, the shrinkage ratio was 0.1% or less. As a result, a multilayer substrate 11 in which no shrinkage in the planar direction occurred was produced. Further, the uppermost layer pattern was screen-printed on this multilayer substrate with an Ag-Pd paste, dried and fired in the same manner as described above. Since the shrinkage of the inner layer substrate was extremely small, there was no printing displacement of the uppermost layer pattern.

Example 2 In FIG. 2, a glass / ceramic green sheet 1 of the substrate material shown in FIG. Next, the sintering-free Al ₂ O ₃ green sheet 2 shown in (b) uses only Al ₂ O ₃ powder (AL-41 manufactured by Sumitomo Aluminum Co., Ltd., average particle size: 1.9 μm) as an inorganic component. A green sheet composition similar to that of the ceramic green sheet 1 was produced by a similar method. The thickness of the glass / ceramic green sheet 1 is about 200 μm, and the Al ₂ O ₃ green sheet 2
Is about 300 μm.

As shown in FIG. 1C, a via conductor 3 was formed on the glass / ceramic green sheet 1 by a screen printing method to form a glass / ceramic green sheet 4 on which a via conductor was formed. As shown in FIG.
Ag on sintered ceramic substrate 13 having N12 layer
The conductive pattern 8 was formed by printing with a conductive paste and firing. As shown in (e), the conductor pattern 8 on the sintered ceramic substrate was transferred onto the glass / ceramic green sheet by applying heat and pressure to the glass / ceramic green sheet 4 with via conductors formed thereon. As shown in (f), a predetermined number of glass / ceramic green sheets on which the conductor patterns are formed are stacked, and the Al ₂ O ₃ green sheets 2 are stacked on both surfaces thereof. The laminate 9 was formed by thermocompression bonding in this state. The thermocompression bonding conditions were a temperature of 80 ° C. and a pressure of 200 kg / cm ² . (G)
As shown in Table 2, the organic binder was decomposed and fired.

The Al ₂ O ₃ layers on both sides of the fired laminate 10 manufactured as described above were removed by ultrasonic cleaning in the same manner as in Example 1 to produce a multilayer substrate 11. Also in this example, when printing and firing were performed using a Cu paste for the uppermost layer, a good low-temperature sintered multilayer substrate was obtained.

[0021]

The method for manufacturing a multilayer ceramic substrate according to the present invention.
According to the above, the glass-ceramic layer is
Is sandwiched between non-sintering materials
Shrinkage in the plane direction is prevented, and shrinkage occurs only in the thickness direction.
Absent. Therefore, metal powder is fired during firing as an electrode material.
Substrate firing instead of conductive material such as paste
Metal conductors with small dimensional changes sometimes cause board cracks
It can be used without any
The reliability of conductors with low resistance
Production of a high multilayer ceramic substrate becomes possible.

[Brief description of the drawings]

1A is a manufacturing process diagram of a multilayer ceramic substrate according to a first embodiment of the present invention; FIG. 1B is a manufacturing process diagram of a multilayer ceramic substrate according to a first embodiment of the present invention; (D) is a manufacturing process diagram of the multilayer ceramic substrate according to the first embodiment of the present invention. (E) is a manufacturing process diagram of the multilayer ceramic substrate according to the first embodiment of the present invention. (G) is a manufacturing process diagram of the multilayer ceramic substrate of the first embodiment of the present invention. (H) is a manufacturing process diagram of the multilayer ceramic substrate of the first embodiment of the present invention.

FIG. 2A is a manufacturing process diagram of a multilayer ceramic substrate according to a second embodiment of the present invention; FIG. 2B is a manufacturing process diagram of a multilayer ceramic substrate according to a second embodiment of the present invention; (D) is a manufacturing process diagram of the multilayer ceramic substrate according to the second embodiment of the present invention. (E) is a manufacturing process diagram of the multilayer ceramic substrate according to the second embodiment of the present invention. (G) is a manufacturing process diagram of the multilayer ceramic substrate of the second embodiment of the present invention. (H) is a manufacturing process diagram of the multilayer ceramic substrate of the second embodiment of the present invention.

3A is a process for manufacturing a conventional multilayer ceramic substrate. FIG. 3B is a process for manufacturing a conventional multilayer ceramic substrate. FIG. 3C is a process for manufacturing a conventional multilayer ceramic substrate.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 glass / ceramic green sheet 2 Al ₂ O ₃ 3 via conductor 4 via conductor formed glass / ceramic green sheet 5 thermoplastic resin layer 6 polymer film 7 Cu foil 8 conductor pattern 9 laminate 10 laminate after firing 11 multilayer Substrate 12 BN layer 13 Sintered ceramic substrate

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Otani 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-5-102666 (JP, A) JP-A-63- 99596 (JP, A) JP-A-5-29740 (JP, A) JP-A-4-263486 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05K 3/46 H05K 3 / 20

Claims (16)

(57) [Claims] [Claim 1] to prepare a green sheet made of a low temperature sintered glass-ceramic material and an organic binder and a plasticizer, gold
An electrode pattern formed using the genus conductor, the green sheet and the further electrode patterned green sheets desired number stacked the low-temperature co-fired glass-ceramic materials
On both sides of the first stack of green sheets made of, the
In the method for manufacturing a multilayer ceramic substrate in the baking temperature of the first laminate to form a second laminate by laminating the green sheet of an inorganic composition that is not sintered, firing the second laminate, the metal Electrode pattern formation using conductor
Uses a conductive pattern formed on a polymer film as glass
・ Transfer to green sheet made of ceramic material
The polymer pattern of the conductor pattern.
The formation on the film is performed by forming a metal conductor on the polymer film.
It is characterized in that it is performed by plating after crimping
A method for manufacturing a multilayer ceramic substrate. 2. The method according to claim 1, wherein the metal conductor is Ag, Ag-Pd, Ag-
2. The method according to claim 1, wherein one of Pt and Cu is a main component. 3. The method according to claim 1, wherein the surface of the metal conductor is roughened. 4. The method according to claim 1, wherein the metal conductor contains CuO as a main component. 5. The method according to claim 1, wherein the second laminate is heat-treated in an air atmosphere to decompose and remove the organic binder, and then heat-treated in a reducing atmosphere to reduce the CuO foil to Cu. Of manufacturing a multilayer ceramic substrate. 6. The inorganic composition which is not sintered at the firing temperature of the glass / ceramic low-temperature sintered substrate material is Al ₂ O ₃ , Mg
O, ZrO ₂ , MgO, SiO ₂ , AlN, BN, TiO
_{3. The} method for producing a multilayer ceramic substrate according to claim 1, wherein at least one of the _two is included. 7. The firing of the second laminate is performed at 800 ° C. to 100 ° C.
2. The method for manufacturing a multilayer ceramic substrate according to claim 1, wherein the method is performed at a temperature of 0 [deg.] C. 8. The method for manufacturing a multilayer ceramic substrate according to claim 1, wherein the glass-ceramic laminate is fired by pressing the glass-ceramic laminate at the time of firing. 9. A film having a thermoplastic resin layer on a polymer film.
The multilayer ceramic substrate according to claim 1, wherein
Plate manufacturing method. 10. The method according to claim 1, wherein the transfer of the conductive pattern is performed while heating. 11. The transfer temperature of the conductive pattern is controlled by the thermoplastic resin.
Wherein the temperature is around the melting point of the conductive resin.
2. The method for manufacturing the multilayer ceramic substrate according to 1. 12. A method for forming a conductive pattern on a polymer film.
Forming a conductor pattern on the film by vapor deposition
The multilayer ceramic substrate according to claim 1, wherein
Plate manufacturing method. 13. A conductor pattern formed by a metal conductor,
The conductor pattern formed on the sintered ceramic is
・ Transfer to ceramic green sheet
2. The multilayer ceramic according to claim 1, wherein
Substrate manufacturing method. 14. The conductor pattern is formed on a sintered ceramic.
It is characterized by printing and firing conductive paste
The method for manufacturing a multilayer ceramic substrate according to claim 13. 15. A sintered ceramic substrate having a surface
Does not react with the conductor paste during formation and
Characterized by having a layer that does not react with the lamic substrate
The method for manufacturing a multilayer ceramic substrate according to claim 1. 16. A layer which does not react with the conductive paste during firing.
Are Al ₂ O ₃ , MgO, ZrO ₂ , MgO, SiO ₂ , Al
Powder layer containing at least one kind of N, BN and TiO ₂
16. The multilayer ceramic according to claim 15, wherein
Substrate manufacturing method.