JPH0442597A - Manufacture of ceramic multilayered wiring board - Google Patents

Abstract

PURPOSE:To make a ceramic board hardly bend so as to improve the thermal shock characteristic of a board joined section by preparing a conductive bonding material of conductive paste containing a resin composition as a binder and/or soldering material. CONSTITUTION:conductive paste 8 containing a resin composition as a binder is applied to a the part 3'a for conducting to another board of a ceramic board 1' as a conductive bonding material with a dispenser, etc., after elements, etc., are mounted on the board 1'. When ceramic boards 1 ad 1' are put together so that their parts 3a and 3'a for conducting to another board can face each other with the conductive bonding material in between and the boards 1 and 1' are heated under a press-contacted condition in, for example, N2 atmosphere, the paste is solidified and the parts 3a and 3'a are joined together. Thus a ceramic multilayered wiring board is produced. When a soldering material and organic bonding agent are used together, heat treatment at the solder melting temperature or higher is required after the bonding agent is solidified by heating the agent under a press-contacted condition. When a soldering material is used as the conductive bonding material, the heating temperature must be set equal to or higher than the melting temperature of the solder material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a ceramic multilayer wiring board in which a plurality of ceramic substrates are laminated and bonded.

[Conventional technology and problems]

In recent years, as electronic devices have become smaller and lighter, there has been a strong demand for higher density wiring boards used to implement electronic circuits. Ceramic wiring boards are no exception.
Multi-layering is being considered and proposed for higher density.

For example, there is a method of stacking and firing ceramic green sheets that are printed with conductor paste in a circuit pattern before a ceramic substrate, but this method has problems such as being prone to cracking or warping during firing.

Therefore, in order to solve the problem of cracking and warping mentioned above, we obtained a plurality of ceramic substrates that were processed into substrates and circuits instead of using green sheets, and used them to heat the conductive parts between the substrates in the circuit at a high temperature (approximately 800 degrees Celsius). ) There is a method in which the two parts are placed facing each other through a treated conductive bonding material and the other parts are overlapped through an insulating adhesive made of a glass composition, and then heated under pressure (Ono et al.; Electronic Materials 1988). May P, pp. 64-68). However, even with this method, it cannot be said that the problem of warping has been sufficiently improved (,
There is a problem that the thermal shock resistance of the bonded portion between the ceramic substrates is insufficient.

[Problem to be solved by the invention]

In view of the above circumstances, it is an object of the present invention to provide a method for obtaining a ceramic multilayer wiring board that is less likely to warp and has excellent thermal shock resistance at bonded portions between ceramic substrates.

[Means to solve the problem]

In order to solve the above problem, in the method for manufacturing a ceramic multilayer wiring board according to the present invention, a plurality of ceramic substrates on which circuits are formed are arranged so that the parts for conduction between the boards in the circuits face each other via a conductive bonding material. The electrically conductive bonding material is a electrically conductive paste and/or a solder material using a resin composition as a binder when the electrically conductive bonding material is stacked on top of each other and subjected to heat treatment.

The circuit-formed ceramic substrate used in this invention is as follows:
Examples include those in which a metal layer (for example, a copper layer) is formed on a ceramic substrate by a plating method such as electroless plating or a vapor deposition method such as sputtering, and then patterned using photolithography technology to provide a circuit. Another option is to print a conductive paste in a predetermined pattern and fire it, but the former method of forming a metal layer and patterning allows for the formation of finer circuits, and has the advantage that the electrical resistance of the circuit itself is lower. . The ceramic substrate may further include a resistive element and a semiconductor element (IC (hybrid IC)).The thickness of the ceramic substrate is usually about 0.3 to 1 nm.

In the present invention, as the conductive bonding material, a conductive paste having a resin composition (for example, a thermosetting resin composition such as an epoxy resin composition) as a binder and a solder material are used alone or in combination. In the case of a conductive paste, it is applied to a predetermined position on the surface of the ceramic substrate using a screen printing method or the like. In the case of solder material, solder paste (a creamy mixture of solder powder and vehicle) is applied to a predetermined position on the surface of a ceramic substrate using a screen printing method, or it is applied to a predetermined position on the surface of a ceramic substrate by dipping it in a solder bath. There are methods such as attaching it to

Heat treatment is usually performed at a temperature of 200°C or lower for conductive pastes and 250°C or lower for solder materials, and preferably at a pressure of about 0.1 to 1 kg/cIa. .

Next, an example of the flow of manufacturing will be described with reference to the drawings.

First, as shown in Fig. 1(a), the through-hole hole 2
．． Ceramic board with 2 (thickness 0.5, length 10at,
Prepare 1.1' (width 10am) and connect it to 270~33
The surface is roughened by immersing it in an 85% phosphoric acid bath at about 0° C. for 3 to 10 minutes. Next, the surface of the substrate is covered with a 10 nm thick copper layer using an electroless copper plating method, and the copper layer is patterned using normal photolithography technology, as shown in Figure 1). Circuit 3 including through holes
... to form. In this case, it is fully possible to set the minimum line width and minimum line distance in the circuit to about 50n.

Subsequently, as shown in FIG. 1(C), a semiconductor element 5, a resistance element 6, and an insulating layer 7 are provided. In the case of the ceramic substrate 1, a commercially available solder resist is applied to the circuit 3 except for the inter-board conduction part (conduction electrode) 3a and the part where the semiconductor element 5 is mounted and cured to form the insulating layer 7. Solder 5. Of course, the semiconductor element may be directly bonded onto the substrate. In the case of the ceramic substrate 1', after the resistance element 6 is formed, a commercially available solder resist is applied to the circuit 3 except for the inter-substrate conduction portion (conduction electrode) 3a and hardened to form the insulating layer 7. To form the resistor element 6, a normal N2 fired resistor paste or
Organic resistor paste is used. Note that the insulating layer may be formed using a glass composition.

After mounting the elements, etc., as shown in FIG. Then, stack the ceramic substrates 1.1' so that the inter-substrate conductive parts 3a and 3'a face each other with the conductive bonding material in between,
For example, if the conductive paste is heated under pressure at 150° C. in a nitrogen atmosphere, the conductive paste will harden and the conductive parts 3a and 3 will be hardened.
'a are combined, and a ceramic multilayer wiring board is completed as shown in FIG. 1(e).

In the ceramic multilayer wiring board shown in FIG. 1(e), the boards were bonded together using only a conductive paste, but
An organic adhesive (for example, solder resist) may be applied to at least a portion of the surface, and the pressure and heating may be performed. When a solder material and an organic adhesive are used together, the adhesive is first cured by pressure heating, and then heat-treated at a temperature equal to or higher than the solder melting temperature (no pressure may be used). The adhesive force between the substrates increases by the amount of adhesive.

In addition, when using solder material as the conductive bonding material,
The heating temperature shall be higher than the solder melting temperature.

Of course, the invention is not limited to the above example.

For example, the roughening treatment on the substrate surface may be omitted.

Although the number of stacked ceramic substrates was two, there is no limit to the number of stacked ceramic substrates, and it goes without saying that it may be as many as three, four, and so on. Furthermore, the conductive bonding material may also be provided on the other ceramic substrate 1.

[For production]

In the method for manufacturing a ceramic multilayer wiring board according to the present invention, a conductive paste and/or a solder material whose binder is a resin composition that requires a low heat treatment temperature is used as the conductive bonding material, and the temperature is lower than that of the conventional method. Because the ceramic substrates are laminated and bonded through heat treatment, warping is less likely to occur. In addition, since the processing temperature is low, even if an adhesive is used in combination to increase the adhesive strength, an organic adhesive is sufficient, and the glass composition does not directly bond the substrates, so the thermal shock resistance of the bonded part between the substrates is reduced. Sexuality improves. Direct bonding using a glass composition is weak, as the glass portion is prone to cracking due to thermal shock applied during subsequent processing steps.

〔Example〕

The present invention will be explained in detail below. This invention is not limited to the following embodiments.

Example 1 - First, the surface of each of three 96% alumina substrates (thickness 0.5 m, length 10 CI 11, width 10 cm) with holes for through holes was coated with a 10 μ thick copper layer by high-speed sputtering. The circuits and through-holes are then patterned using conventional photolithography techniques.
... was formed. The minimum line width and minimum line distance in the circuit is 5
0Ir@.

Next, a resistive element was formed using N, fired type resistor paste, and then a portion of the circuit of the ceramic substrate other than the inter-board conduction portion was covered with a solder resist and heat treated to form an insulating layer.

Next, a copper (conductive) paste with an epoxy resin composition as a binder is applied as a conductive bonding material to the part for inter-board conduction of the ceramic substrates using a dispenser, and the three ceramic boards are connected to the part for inter-board conduction. They are stacked facing each other with conductive paste interposed between them, and when heated under pressure at 150°C in an N2 atmosphere, the conductive paste hardens and the conductive parts between the boards are bonded, forming a ceramic multilayer wiring board. completed. The obtained ceramic multilayer wiring board had sufficient electrical continuity and adhesion between the substrates.

Example 2 - Commercially available solder paste was used as the conductive bonding material, and N
A ceramic multilayer wiring board was obtained in the same manner as in Example 1, except that the solder was heated under pressure in an atmosphere at 230° C., which exceeds the solder melting temperature, and then allowed to cool to solidify the solder. , electrical conductivity, and adhesion between the substrates were all sufficient.

Example 3 - First, a 96% alumina substrate (thickness 0.5 wa, length 1
A high-temperature-treated copper paste was printed in a predetermined pattern on the surface of each of the two sheets (width 10 cm) using a screen method. The minimum line width and minimum distance between lines in the printing pattern is 1
It is 50μ.

Next, N2 firing type resistor paste was printed in a predetermined position, and the parts of the circuit on the ceramic board other than the part for inter-board conduction were covered with glass paste, and fired at a temperature of 950°C in an N2 atmosphere to complete the circuit. A resistive element and an insulating layer were formed at the same time.

Thereafter, a ceramic multilayer wiring board was obtained in the same manner as in Example 1. The completed ceramic multilayer wiring board has electrical continuity,
Adhesion between the substrates was in a sufficient state in all cases.

Example 4 - 96% alumina substrate (thickness 0.5
Two pieces of paper crane (10QII length, 10CO+ width) were prepared and immersed in an 85% phosphoric acid bath at about 300° C. for 5 minutes to roughen the surface. Next, the surface of the board is covered with a copper layer with a thickness of 10 μm using an electroless copper plating method, and the copper layer is selectively etched and patterned using normal photolithography technology to form through holes. A circuit containing the following was formed. The minimum line width and minimum line distance in the circuit is 50μ
That's about it.

Next, an organic resistor paste is applied to a predetermined position on one ceramic substrate and cured to form a resistance element, and then a commercially available solder resist is applied to the parts other than the parts for inter-board conduction and heat-treated. An insulating layer was formed.

Regarding the other ceramic substrate, a commercially available solder resist was applied to the parts other than the parts for inter-board conduction, and after heat treatment was performed to form an insulating layer, a semiconductor element was soldered.

Thereafter, in the same manner as in Example 1, a ceramic multilayer wiring board was obtained.

Example 5 - After applying the conductive paste for the conductive bonding material, a solder resist, which is an organic adhesive, was applied to several places on the surface of the insulating layer using a dispenser, and then pressure and heating were performed. A ceramic multilayer wiring board was obtained in the same manner as in Example 4.

Compared to the ceramic multilayer wiring board of Example 4, the ceramic multilayer wiring board of Example 5 had more sufficient adhesion between the boards because an adhesive was used in combination.

Comparative Example 1 In Example 3, a high-temperature firing type conductive bonding material made of copper powder, glass powder, and vehicle is applied to the conductive part between the boards, and then pressure is applied at a temperature of 900°C in N8. A ceramic multilayer wiring board was obtained in the same manner except that the substrates were heated and directly bonded to each other through an insulating layer made of a glass composition.

The ceramic multilayer wiring board of Comparative Example 1 had greater warpage than that of Example 3, and the thermal shock resistance of the bonded portion between the boards was low.

〔Effect of the invention〕

As described above, in the method for manufacturing a ceramic multilayer wiring board according to the present invention, the heat treatment temperature during lamination bonding of ceramic substrates is lower than that in the past, so warping is less likely to occur. Since there is no need to bond the substrates to each other, it is possible to improve the thermal shock characteristics of the bonded portion between the substrates.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view for explaining steps in carrying out an example of the method for manufacturing a ceramic multilayer wiring board of the present invention. 1.1'... Ceramic substrate 3 on which a circuit is formed...
・Circuit 3a, 3/a...Inter-board conduction part 8
... Conductive Paste Procedure Amendment (Fig. 1(d) 1.1 Abbreviation of JushiR Patent Application No. 151259/1999 2, Name of Invention Method for Manufacturing Ceramic Multilayer Wiring Board 3, Person Making Amendment) Relationship to the case Patent applicant address 1048 Oaza Kadoma, Kadoma City, Osaka Name (583) Representative of Matsushita Electric Works Co., Ltd. (Kaikaishi Toshio Miyoshi 4, Agent 6, Specification subject to amendment 7, Contents of amendment ■ On page 4, lines 6 to 8 of the specification, it says, "Also, the same level as for ceramic substrates." Multi-layering is done at a temperature that does not melt.Also, the thickness of the ceramic substrate is usually about 0.1 to 1 inch.''.■ It is corrected to read ``Solder material'' on page 5, lines 1 to 3 of the specification. In the case of···
preferable. "In the case of soldering materials, it is preferable to conduct the soldering at a temperature of 400°C or less and apply a pressure of about 0.1 to 1 kg/ant. Furthermore, after forming a multilayer board, it is preferable to conduct In order to prevent the solder between the boards from melting and shifting during the solder reflow process used to mount components such as elements, it is preferable to use a high-temperature solder material that has a melting point (liquidus temperature) higher than the solder reflow temperature. ”, he corrected. ■ On page 6, line 15 of the specification, the word "dispenser" has been replaced with "dispenser or well-known screen printing."
I am corrected. ■ On page 7 of the specification, between the second and third lines, it says, ``Here, we have explained a method for multilayering a board on which components such as semiconductor elements are mounted. It goes without saying that you can implement it later." ■ “Dispenser” on page 9, lines 12-13 of the specification
Correct the statement to "screen printing." ■ On page 12, line 3 of the specification, the phrase "soldered" was replaced with "soldered using a solder material with a melting point of 183°C."
I am corrected. ■ Insert the following text between lines 15 and 16 on page 12 of the specification. [Example 6] A commercially available high-temperature solder paste with a liquidus temperature of 240°C was used as the conductive bonding material, and after heating and pressurizing it at 280°C, which exceeds the solder melting temperature, in an N2 atmosphere, the solder was soldered by allowing it to cool. A ceramic multilayer wiring board was obtained in the same manner as in Example 1, except that the ceramic multilayer wiring board was solidified, and the electrical conductivity and adhesion between the boards were both sufficient. ”

Claims (1)

[Claims] 1. Manufacturing a ceramic multilayer wiring board in which a plurality of ceramic substrates on which circuits are formed are stacked so that the conductive parts between the circuits face each other via a conductive bonding material, and then heat treated. A method for manufacturing a ceramic multilayer wiring board, characterized in that the conductive bonding material comprises a conductive paste and/or a solder material using a resin composition as a binder.