JPS60137884A - Manufacture of ceramic multi-layer wiring circuit substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for manufacturing a ceramic multilayer wiring circuit board,
It is particularly suitable for high-precision ceramic substrates on which pins for inputting and outputting electrical signals are attached or on which semiconductor components are mounted to form functional modules.

[Background of the invention]

In recent years, ceramic substrates with multilayer wiring have been used as substrates for mounting semiconductor components at high density. The ceramic insulators used in these devices are often sintered bodies containing alumina (A a s = o 3) as a main component. Conventional ceramic multilayer wiring circuit boards are made by forming internal wiring and conductor connections between layers on green sheets made by bonding ceramic powder with resin, laminating and pressing a large number of sheets, and then firing them in a furnace without applying pressure. was. The biggest drawback of this manufacturing method is that shrinkage deformation and warping occur when the green sheet laminate is fired. Firing shrinkage is
It fluctuates due to slight temperature changes inside the furnace, and especially in high-density wiring boards, this slight variation can cause misalignment in the connections of semiconductor components and pin terminals for inputting and outputting electrical signals. Become. Furthermore, warping during firing may cause connection failures when semiconductor components are mounted.

[Purpose of the invention]

An object of the present invention is to provide a ceramic multilayer wiring circuit board for connecting pins for inputting and outputting electrical signals and semiconductor components to a ceramic board with high precision, and a method for manufacturing the same.

[Summary of the invention]

The method of manufacturing a ceramic multilayer wiring circuit board according to the present invention is characterized in that firing is performed under the condition that a pressure is applied perpendicularly to the surface to which pins for inputting and outputting electric signals and semiconductor components are connected.

Ceramic insulating sintered bodies used for ceramic multilayer wiring circuit boards usually contain 2 to 30% (heavy tons) of glass component as a sintering aid. Therefore, the glass powder interposed between the ceramic powders is at the softening point of the glass. When the temperature reaches the above temperature, the entire part softens almost simultaneously and flows to surround the ceramic powder, forming a homogeneous sintered body.
1400-1600℃ for so-called liquid phase baking.
It can be sintered at relatively low temperatures and in a short time. As will be seen, the main factor determining the progress of sintering is not the main ceramic material, but the glass component as a sintering aid, and its softening point. Conversely, even if the main ceramic material is mixed in some parts, if a glass component of the same composition is used as a sintering aid, the same liquid phase sintering will be performed, resulting in uniform sintering. As a manufacturing method for combining insulating layers made of different ceramic main materials, the most suitable method is to first form the insulating materials into green sheets, process them into green sheets, and then laminate them together and sinter them. In forming this green sheet, in addition to the ceramic main material and the above-mentioned sintering aid of the glass component, binders, plasticizers, solvents, etc. are used. For example, binders include synthetic resins such as polyvinyl alcohol, polyvinyl butyral, and polymethacrylic acid; plasticizers include dioctyl phthalate and butyl butyl phthalyl glycolate; and solvents include methanol, 1-recurne, toluene, and te-1- These include lachlorethylene and butyl alcohol. These are weighed and mixed to form a slurry. Next, this slurry is applied onto a support such as a silicon-treated polyester film, adjusted to a desired thickness using a doctor blade, etc., and then dried to form a green sheet. This green sheet is provided with through holes for connecting conductor circuits, and furthermore, molybdenum or tungsten paste as conductor paths is printed inside the through holes and according to the circuit pattern. A plurality of green sheets whose main component is ceramic processed in this way are laminated together into a desired configuration and fired in a neutral or reducing atmosphere. The reason why a reducing atmosphere is required is to prevent molybdenum, tengesten, or copper used in the conductor circuit from being oxidized and volatilized.

However, in order to oxidize and disperse the binder or plasticizer contained in the green sheet, it is desirable to include moisture as an oxidation source in the atmosphere during the firing period. When firing in a reducing atmosphere, if a glass powder containing an oxide that is easily reduced, such as lead oxide or titanium oxide, is used, the i+'8 edge properties of the sintered body, that is, the substrate, may deteriorate.

Therefore, the glass powder should preferably be one that does not substantially contain such compounds. However, firing in the atmosphere is possible for materials that use gold or silver as the conductive material.

Conventionally, when firing green sheet laminates, a large number of green sheet laminates were placed on a center and fired without pressure.

In this case, firing shrinkage occurs in the width direction and thickness direction,
Due to slight temperature differences in the furnace, the firing shrinkage rate fluctuates, and the metallization patterns for connecting pins used for inputting and outputting electrical signals and the metallization patterns for mounting semiconductor components also fluctuate, resulting in misalignment. , a connection failure has occurred.

Furthermore, since firing is performed without pressure, the substrate often warps due to the flow of atmospheric gas and firing conditions. this is,
This is due to the difference between the ambient temperature and the center temperature, and the difference in firing shrinkage rate and thermal expansion coefficient due to different materials, such as ceramic materials and conductive materials, ceramic materials with different compositions, etc.

Therefore, in order to eliminate misalignment and warping of the metallized pattern due to these causes, a load was applied in the thickness direction during firing to eliminate firing shrinkage in the width direction (plane direction) and prevent warping from occurring. The thus fired ceramic multilayer wiring circuit board is plated with nickel or the like, and then pins or leads made of Kovar or the like are soldered with a brazing material such as silver solder. Then, semiconductor components are mounted to form a single functional module.

[Embodiments of the Invention] Examples of the present invention will be shown below. Note that in each of the following examples, "part" means "part by weight" and "1%" means "% by weight."

Example 1 Mullite powder with an average particle size of 57zm or less (3AQs+03
23in2) '70 copies, 5in2:AQ, 03:M
5.9 parts of polyvinyl butyral were placed in a ball mill and dry mixed for 3 hours to 30 parts of glass powder material 1'+ having a composition of g0=51.3:34.9:13.8 (weight ratio). Furthermore, butyl phthalyl glycolate 1.9
1 part, 23 parts of 1-lichlorethylene, 6 parts of 1-lichlorethylene, and 8 parts of butyl alcohol were added and mixed for 20 hours to prepare a slurry. Air bubbles are removed from the slurry by vacuum degassing. The slurry was then applied to a thickness of 0.25 m onto a silicone coated polyester film support using a doctor blade and dried through an oven.
Create Murai 1-1 Glass Green Sea 1-. After cutting this green sheet into a size of 200×20On++n, through holes are punched at predetermined positions by punching. Furthermore, molybdenum powder: ethyl cellulose:
Polyvinyl butyral: Butyric rubitol acetate:
Dibenzylidene-D-sorbitol = 88:2:0.7
:21:2 (weight ratio) conductor paste is printed according to a predetermined circuit pattern by screen printing. Semiconductor paste was also filled into the through hole to connect between the eyebrows. Next, five green sheets were laminated according to the positions of the guide holes, and the sheets were laminated under pressure at a temperature of 90°C. Next, the stacked green sheets are placed in a firing furnace, and the hydrogen
It was fired under a load in a nitrogen atmosphere containing 7% by volume and a trace amount of water vapor. To 1200°C, the temperature was raised at a rate of 00°C or less for 1 hour without applying any pressure, the resin content was removed, and then a pressure of 30 kg/c11 was applied and the maximum temperature was maintained at 1540°C for 1 hour for firing. . This board is
The metallized surface for connecting leads used for inputting and outputting electrical signals and the surface on which semiconductor components are mounted are smooth and unwarped, and have high precision according to desired dimensions. This is because the pressure was applied in the thickness direction of the substrate, so there was no firing shrinkage in the plane direction (width direction), and firing shrinkage occurred only in the thickness direction. After electroless nickel plating was applied to this substrate, a Kovar lead was connected to the back conductor Jt7J using a gold-tin alloy using a conventional method using a carbon jig. Furthermore, semiconductor components were connected to the surface conductor layer with solder. There was no deviation in the connection position between the Kovar lead and the semiconductor component, and the connection surface was smooth, so no connection failure was observed.

Example 2 Alumina powder passing through 325 mesh (AQ, 0390 parts, SiOt, :AQ203 :Mg0=51.3:
34.9 : ], 3.8 (by weight) 10 parts of glass powder material are dry mixed in a ball mill for an amount of time. Further, 5.9 parts of polyvinyl butyral, 2.4 parts of dioctyl phthalate, 23 parts of trichloroethylene, 9 parts of perchloroethylene and 6 parts of butyl alcohol were added and mixed for 3 hours to prepare a slurry. Air bubbles are removed from the slurry by vacuum degassing. The slurry is then spread onto a polyester film support using a doctor blade.
It is coated to a thickness of 3+on+ and dried in an oven to produce an alumina-glass green sheet. After cutting this green sheet into a size of 200 x 200 + nm, through holes are punched at predetermined positions using a punching method.

Further, a conductive paste having a weight ratio of tungsten powder: nitrocellulose: ethylene cellulose: polyvinyl butyral = 1-lichloroethylene = 100:3:1:2:23 (weight ratio) is printed according to a predetermined circuit pattern by a screen printing method. The conductive paste was also filled into the through hole for the connection between the eyebrows. 111 of these green sheets were stacked with the guide holes aligned, and pressed and subjected to Ml+ at a temperature of 90°C. Next, the laminated green seas 1 to 1 were placed in a firing furnace and fired under a load in a nitrogen atmosphere containing 3 to 7% by volume of hydrogen and a very small amount of water vapor.

Up to 1200℃, the atmosphere must contain a trace amount of water vapor, and
The resin content was removed without applying a load at a heating rate of 100°C or less, and then a pressure of 50 kg/cnY was applied and the product was fired at a maximum temperature of 1600'C for 1 hour.

Because pressure was applied to this board in the thickness direction, the width direction (
There is no firing shrinkage in the plane direction), and there is firing shrinkage only in the thickness direction. Therefore, the metallized surface for connecting pins used for inputting and outputting electrical signals and the surface on which semiconductor components are mounted are smooth and free from warp, and are highly accurate to desired dimensions. After electroless nickel plating was applied to this substrate, Kovar pins were connected to the back core layer using silver solder using a conventional method using a carbon jig. Furthermore, a silicon semiconductor element was mounted face-down on the surface layer and connected directly to the substrate using solder. There was no deviation in the connection position between the Kovar pin and the silicon semiconductor element, and the connection surface was smooth, so no connection failure was observed.

Example 3 60 parts of silica powder (SiO7) passing through 325 mesh,
S i OQ: A Q QO,: M g O: C
40 parts of a glass powder material having a composition of a0=55:30:9:6 (weight ratio) was placed in a ball mill and mixed in a axial manner for 6 hours. Furthermore, add 5.9 parts of polyvinyl butyral.
After mixing for 1 hour, 2.3 parts of butyl phthalyl glycolate, 23 parts of trichlorethylene, 6 parts of tetrachloroethylene, and 8 parts of butyl alcohol were added and mixed for 244 hours to form a slurry.

Air bubbles are removed from the slurry by vacuum degassing.

The slurry is then applied to a thickness of 0.25 ++ o on a polyester film support using a doctor blade and dried through an oven to produce a silica-glass green sea 1-. This green sheet is 200 x 2
After cutting to a size of 0.00 am, through holes are punched at predetermined positions using a punch method. More molybdenum powder:
Ethyl cellulose: Borivinyl butyral: Butyl carbitol acetate: Shihenzilidene-D-Solby I~
A conductive paste having a weight ratio of 88:2:0.7:21:2 is printed according to a predetermined circuit pattern by screen printing. The conductive paste was also filled in the through holes for adhesion between layers. Next, seven green sheets were laminated with the guide holes aligned, and the sheets were laminated under pressure at a temperature of 90°C. Next, the laminated green sheets were placed in a firing furnace and fired under a load in a nitrogen atmosphere containing 3 to 7% by volume of hydrogen and a trace amount of water vapor. 1200
℃, the temperature is increased at a rate of 100℃ or less per hour without applying pressure to remove the resin, then the pressure of 25kg/cJ is applied to the door, and the maximum humidity is 1500℃ and held for 1 hour to bake. did. Because pressure was applied to this substrate in the thickness direction, there was no firing shrinkage in the width direction (plane direction), and there was firing shrinkage only in the thickness direction. Therefore, the metallized surface for connecting pins used for inputting and outputting electrical signals and the surface on which semiconductor components are mounted are smooth and free from warp, and are highly accurate to desired dimensions. After electroless nickel plating was applied to this substrate, Kovar pins were connected to the back conductor layer using a gold-tin alloy in a conventional manner using a carbon jig. Furthermore, on the first surface layer, a silicon semiconductor element was mounted face down and directly connected to the substrate with solder. There was no deviation in the connection position between the Convar pin and the silicon semiconductor element, and the connection surface was smooth, so no connection failure was observed. The silica used here is quartz and quartz glass.

Grease 1 to Barai 1 to tridymite, and contains at least one kind of polymorphs of stiff silica.

Example 4 Murai 1 to 1 produced in Examples 1 to 3 above. Glass-based, alumina-glass-based and silica-glass-based Green Sea 1
At least two or more types of ~ are used. After cutting these green seas 1- into a size of 200 x 200 ++ un, through holes are punched at predetermined positions using a punching method. Further, the molybdenum paste or tungsten paste used in Examples 1 to 3 above is printed according to a predetermined circuit pattern by screen printing. The conductive paste was also filled into the through holes for connection between layers.

Alumina-glass Green Sea 1- is used for the insulating layer in contact with the metallized layer for connecting pins used for input/output of electricity (Part 1) and the insulating layer in contact with the metallized layer for mounting semiconductor components. However, the other insulating layers mentioned above in contact with the internal wiring layer are coated with glass-based green sheet 1-
Alternatively, a silica-glass green sheet was used. Align the guide hole of the green sheet and T:
Five sheets were laminated and laminated under pressure at a temperature of 90°C. Next, the stacked green sheets are placed in a firing furnace, and hydrogen is heated at 3 to 7% by volume.
The material was fired under a load in a nitrogen atmosphere containing a small amount of water vapor. 10 per hour up to 1200℃
No pressure was applied at a heating rate of 0°C or less, the resin content was removed, and then a pressure of 30 kg/cIil was applied, and the maximum temperature was 15°C.
It was held at 60° C. for 1 hour and fired. The two insulating layers exposed on the surface are alumina-glass sintered bodies, and the other insulating layers are alumina-glass sintered or silica-based.
A ceramic multilayer wiring circuit board made of a glass-based sintered body and having five insulating layers and six conductor layers was manufactured. This board is
Because pressure was applied in the thickness direction, there was no firing shrinkage in the width direction (plane direction), but firing shrinkage only in the thickness direction. For this reason, the metallized surface for connecting leads used for inputting and outputting electrical signals and the surface on which semiconductor components are mounted must be flat. 1) There is no warping and the desired dimensions are met with high accuracy. Normally, when the IJL layer is made of IJL material and fired without processing, warping occurs due to the difference in firing shrinkage rate and coefficient of thermal expansion, but in this example, it is fired with a load applied. Because different materials were used, no warping occurred on the board.The bonding condition between each layer of this board was good,
After electroless nickel plating, a Kovar lead was connected to the back conductor layer using a silver loss in the usual manner using a carbon jig. In addition, a chip carrier made of ceramic whose main component is alumina was connected to the surface conductor layer with solder. The tensile strength of the lead was 1 kg/pin or more. This value was almost the same as that of a substrate whose entire layer was made of a sintered body whose main component was alumina, and the strength was sufficient for practical use. Also, the solder connection part of the chip carrier is -
No disconnection occurred after 3000 cycles or more of temperature cycles from 65°C to +150°C. This value is almost the same as that of a board whose entire layer is made of a sintered body whose main component is alumina, and the strength was sufficient to guarantee a sufficient connection life even under harsh usage conditions. On the other hand, the signal propagation delay time into the internal wiring circuit is 7.7 ns/m when an insulator whose main component is mullite is used for the internal insulating layer.
7. When an insulator containing silica as a main component is used for the internal insulating layer. Ons/m. These values correspond to the dielectric constant of the insulating layer. The dielectric constant of an insulator whose main component is mullite is 5.5, and that of an insulator whose main component is silica is 4.5. In addition, in a substrate whose entire layer is made of a sintered body whose main component is alumina, the dielectric constant is approximately 9.5, and the signal propagation delay time is 10.2Hs/
m, so in this example the signal propagation delay time is 75~
Example 5 270 parts of alumina, mullite or silica powder Glass powder (composition shown in Table 1): 30 parts Conductor paste 100 parts of dicopper powder 3 parts of nitrocellulose 1 part of ethyl cellulose 2 parts of polyvinyl butyral 23 parts of trichlorethylene Thickness of green sheet: 0.25 m11 A green sheet laminate was produced in the same manner as in Examples 1 to 4, except for the above changes.

The laminated green sheets were placed in a firing furnace and fired under a load in a nitrogen atmosphere. No pressure is applied until the softening point of the glass used as a sintering aid, and the resin content is removed.
Firing was performed by applying a pressure of kg/cJ. The firing temperature was set to be higher than the softening point of glass as a sintering aid, and below 1083°C, which is the melting point of copper as a conductive material. The bonding state between each layer of the ceramic multilayer wiring circuit board produced in this way is good, and the metallized surface for connecting pins used for inputting and outputting electrical signals and the surface for mounting semiconductor components are smooth and free from warping. , with high precision according to the desired dimensions. Because pressure was applied to this substrate in the thickness direction, there was no firing shrinkage in the width direction (plane direction), and there was firing shrinkage only in the thickness direction. After electroless nickel plating was applied to this substrate, Kovar pins were connected to the back conductor layer using a gold-tin alloy in a conventional manner using a carbon jig. Also, in the surface layer.

The silicon semiconductor element was mounted face down and directly connected to the board with solder. There was no deviation in the connection position between the Kovar pin and the silicon semiconductor element, and the connection surface was smooth, so no connection failure was observed.

Example 6 Conductor paste: 100 parts of silver or gold powder 3 parts of 21-cellulose 1 part of ethyl cellulose 2 parts of polyvinyl butyral 2 parts of trichlorethylene A ceramic multilayer wiring circuit board was fabricated. The bonding between each layer of this ceramic multilayer wiring circuit board is good, and the metallized surface for connecting pins used for inputting and outputting electrical signals and the surface for mounting semiconductor components are smooth and unwarped, and conform to the desired dimensions. High precision. Since pressure is applied to this substrate in the thickness direction, there is no firing shrinkage in the width direction (plane direction), and there is firing shrinkage only in the thickness direction.

After electroless nickel plating was applied to this substrate, Kovar pins were connected to the back conductor layer using a gold-tin alloy in a conventional manner using a carbon jig.

Furthermore, a silicon semiconductor element was mounted face-down on the surface layer and connected directly to the substrate using solder.

There was no deviation in the connection position between the Kovar pin and the silicon semiconductor element, and the connection surface was smooth, so no connection failure was observed.

[Effects of the Invention] According to the present invention, since a load is applied in the thickness direction during firing, there is no firing shrinkage in the width direction (plane direction), so the pin (
There is no deviation in the connection positions of the leads) and the silicon semiconductor element (semiconductor part) to the substrate, and the connection surfaces are smooth, so no connection defects are observed.

[Brief explanation of drawings]

Fig. 1 shows the layer structure of a ceramic multilayer wiring circuit board according to Example 1 of the present invention and a cross-sectional view of a functional module using the board, and Fig. 2 shows the layer structure of a ceramic multilayer wiring circuit board according to Example 2 of the present invention. , is a cross-sectional view of a functional module using the substrate. ■... Sintered body mainly composed of mullite, 2... Molybdenum internal wiring conductor, 3, 13... Ceramic multilayer wiring circuit board, 4... Kovar lead, 5, 15... Solder, 6 ... Chip carrier, 11 ... Sintered body mainly composed of alumina, 12 ... Tungsten internal wiring conductor, 14 ... Kovar pin, 16 ... Silicon semiconductor element. Agent Patent Attorney Akio Takahashi

Claims (1)

[Claims] 1. A method for manufacturing a ceramic multilayer wiring circuit board, which is characterized in that a load is applied in the thickness direction during firing in a ceramic multilayer wiring circuit board formed by alternately laminating ceramic insulating materials and conductive materials.