JPS6263491A - Manufacturing multilayer thick film board - 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] [Technical Field of the Invention] The present invention relates to a method for manufacturing a multilayer thick film substrate formed by laminating a plurality of thick film substrates each having a circuit pattern formed on an insulating substrate.
In particular, the present invention relates to an insulating substrate that can be effectively degreased when forming a conductive layer on an insulating substrate that can be fired at a low temperature in an inert atmosphere.

[Technical Background of the Invention] As is well known, in the field of electronic equipment, for example, hybrid integrated circuits are increasingly being used to reduce size and weight. This hybrid integrated circuit is generally
It is constructed by soldering chip-type passive elements and active elements without lead wires to a thick film substrate made by printing conductive materials, resistive materials, etc. on an insulating substrate. by the way,
Conventional thick film substrates generally use alumina as the insulating substrate material and tungsten, molybdenum, etc. as the conductive material, so the firing temperature is 1600°C.
However, there is a problem in that the conductor resistance of the formed conductor layer is also high.

Therefore, in recent years, insulating substrates that can be fired at temperatures as low as 1000°C or less have been used, and gold and gold have been used as conductive materials.
A conductor layer with low conductor resistance has been formed by using silver-palladium, copper, etc., and the number of manufacturing steps can be reduced by firing the insulating substrate and the conductor layer at the same time. is also being carried out.

Particularly recently, in order to achieve even higher density packaging, a plurality of thick film substrates formed as described above are laminated to form a multilayer structure. 6th
The figure shows a conventional method for manufacturing such a multilayer thick film substrate. First, as shown in Figure 6(a), a binder such as acrylic resin and a solvent such as butyl calpitol are mixed with glass/ceramic powder, and a plate thickness of approximately 0.3111 m is prepared using a doctor blade method or the like. A raw substrate 11 called a green sheet is formed.

Next, as shown in FIG. 6(b), by punching with a press or the like, the green substrate 11 is stamped at a predetermined position with a diameter of 0.
A through hole 11a having a diameter of about 5φ is formed at the same time as the outer shape of the raw substrate 11. After that, as shown in Figure 6(c), gold, silver
A conductor paste containing conductor particles such as palladium or copper, glass frit, and a solvent was printed into the through holes IJ, a of the raw substrate 11 by screen printing using a vacuum suction method, and then heated at 150° C. for 10 minutes. The through hole 12 is formed by drying. Next, as shown in FIG. 6(d), the conductive paste is printed on the raw substrate 11'' so as to surround the through holes 12 using a screen printing method, and
A conductor layer 13 is formed by drying with C for 10 minutes, and one thick film substrate 14 is formed thereon.

A plurality of thick film substrates 14 are formed through the steps shown in FIG. 7(a), and then, as shown in FIG. Next, as shown in FIG. 7(b), the raw substrate 11 and the through holes 12 . In order to decompose or burn out the resin components contained in the circuit pattern made of the conductor layer 13, degreasing is performed in an inert atmosphere using, for example, an electric furnace. Thereafter, as shown in FIG. 7(C), the raw substrate 11 and the circuit pattern are simultaneously fired 17 in an inert atmosphere, thereby forming a multilayer thick film substrate.

[Problems of Background Art] However, the following problems occur in the conventional method of manufacturing a multilayer thick film substrate as described above. In other words, if a conductor paste containing base metals such as copper or nickel is used, it is necessary to degrease and bake it in an inert atmosphere to prevent oxidation of the copper. This makes the selection of resin and degreasing conditions difficult. For example, as shown in Figure 8, the degreasing conditions include increasing the temperature at a rate of 50°C/H and increasing the temperature to 700°C.
It is necessary to control the temperature so that the temperature is maintained for about 3 hours, which takes a long time of 10 hours or more.

In addition, when selecting the resin to be used for the raw substrate 11, since it is not completely decomposed in an inert atmosphere, it reacts with the glass particles in the raw substrate 11 during degreasing and forms carbon in the insulating substrate after firing. Some of it will remain. Therefore, as shown in FIG. 9, even if the firing temperature is increased, the interlayer insulation resistance of the insulating substrate is low, which is insufficient for practical use.

Here, conventionally, in order to improve the degreasing conditions, a method of partially mixing several hundred p, p, m, or so of oxygen during degreasing is sometimes used; There is also the problem that the conductor resistance of the conductor layer 13 becomes higher than 1001Ω as shown in FIG. 10.

[Purpose of the Invention] This invention has been made in consideration of the above circumstances, and provides a method for effectively degreasing an insulating substrate when forming a conductive layer that is fired in an inert atmosphere on an insulating substrate that can be fired in an inert atmosphere. It is an object of the present invention to provide an extremely good method for manufacturing a multilayer thick film substrate in which the interlayer insulation resistance value and the conductor resistance value of the conductor layer can be sufficiently put to practical use.

[Summary of the invention] That is, the method for manufacturing a multilayer thick film substrate according to the present invention includes:
An insulating substrate made of a material containing glass particles is degreased in an oxidizing atmosphere at a temperature higher than the softening temperature of the glass particles and lower than the sintering temperature, and a circuit pattern containing a conductive layer made of a base metal material is formed on the insulating substrate. to form a thick film substrate. By stacking a plurality of thick film substrates formed in this way and firing them simultaneously in an inert atmosphere, a conductive layer that can be fired in an inert atmosphere is formed on an insulating substrate that can be fired at low temperatures. When forming the insulating substrate, the insulating substrate is effectively degreased so that the interlayer insulation resistance value and the conductor resistance value of the conductor layer are sufficiently high for practical use.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. First, as shown in FIG. 1(a), for example, 50 parts each of MgO-5t02-based isocontainer and lead-free barium-based amorphous glass powder are mixed, and acrylic resin,
Mix methyl ethyl ketone, plasticizer, etc. to form a slurry, and use the doctor blade method to make a plate with a thickness of 0.3 cm.
A raw substrate 15 having an area of about 60 parts 2 is formed. Next, as shown in FIG. 1(b), a plurality of through holes L5a are formed at predetermined positions on the raw substrate 15 using a punch with a diameter of 0.5φ.

Thereafter, as shown in FIG. 1(c), the raw substrate 15 is degreased in an oxidizing atmosphere at a temperature of 850° C. for 1.5 hours. In this case, since the softening temperature of the glass frit of the raw substrate 15 is 850°C, all the resin in the raw substrate 15 is almost completely decomposed at the degreasing temperature of 850°C as described above. In addition, melting of the glass frit promotes fusion with the MgO-5i02-based additive, so that even before sintering, the transverse rupture strength of the raw substrate 15 after degreasing is 1200 kg/ em2, and the surface roughness of the raw substrate 15 is approximately 4 μm, which is sufficient strength for forming a conductor layer to be described later.

Next, as shown in Figure 1(d), a conductor paste containing conductor particles such as gold, silver-palladium, or copper, glass frit, and a solvent is applied to the green substrate by screen printing while using a vacuum suction method. 15 through holes 15a, 120
The through hole 16 is formed by drying at .degree. C. for 10 minutes.

Next, as shown in FIG. 1(e), the conductive paste is printed on the raw substrate 15 using a screen printing method so as to surround the through hole 1B, and dried at 120° C. for 10 minutes to form a conductive paste. 17, and one thick film substrate 18 is formed thereon.

Through the steps described above, a plurality of thick film substrates 18 are formed,
After that, as shown in FIG. 2(a), a plurality of thick film substrates 1
8 are laminated and press-bonded. Next, as shown in FIG. 2(b), a circuit pattern consisting of the raw substrate 15, the through hole 1B, and the conductor layer 17 constituting each thick film substrate 18 is
The multilayer thick film substrate is constructed by firing in an inert atmosphere at a temperature of 950° C. for 1 hour. In this case, especially during sintering, when the glass frit included in each thick film substrate 18 is melted again and liquid phase sintered, each thick film substrate 18
This will allow them to be firmly bonded.

Therefore, according to the method of the above embodiment, since the raw substrate 15 is degreased in an oxidizing atmosphere, the time required for degreasing is reduced to less than 1/10 of the conventional method, as shown in FIG. At the same time, the resin used for the raw substrate 15 can be easily selected.

In addition, since the resin on the raw substrate 15 is completely degreased, the insulation resistance becomes much higher than before at the same firing temperature, as shown in FIG. 4, making it suitable for practical use. It is something. Furthermore, as shown in FIG. 5, the conductor resistance of the conductor layer 17 is about 31Ω, which is about 1/4 of the conventional resistance, which is suitable for practical use.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] Therefore, as detailed above, according to the present invention, when forming a conductor layer on an insulating substrate that can be fired at a low temperature in an inert atmosphere, the insulating substrate can be effectively degreased. Therefore, it is possible to provide an extremely good method for manufacturing a multilayer thick film substrate in which the interlayer insulation resistance value and the conductor resistance value of the conductor layer can be sufficiently reduced for practical use.

[Brief explanation of the drawing]

1 and 2 are side views showing an embodiment of the method for manufacturing a multilayer thick film substrate according to the present invention, respectively, and FIG. 3 shows the relationship between the degreasing time and firing time and the temperature in the same embodiment. Figure 4 is a characteristic diagram showing the relationship between the firing temperature and the interlayer insulation resistance of the insulating substrate in the same example, and Figure 5 is a characteristic diagram showing the relationship between the firing temperature and the conductor resistance of the conductor layer in the same example. 6 and 7 are side views showing the conventional method for manufacturing a multilayer thick film substrate, respectively. FIG. 9 is a characteristic diagram showing the relationship between the firing temperature and the interlayer insulation resistance of the insulating substrate in the conventional example, and FIG. 10 is a characteristic diagram showing the relationship between the firing temperature and the conductor resistance of the conductor layer in the same conventional example. 11... raw board, 12... through hole, 13...
・Conductor layer, 14... Thick film substrate, 15... Raw substrate, 1
6...Through hole, 17...Conductor layer, 18...
Thick film substrate. Applicant's representative Patent attorney Takehiko Suzue Figure 1, Figure 2, Figure 6, Figure 7, Figure 8, 2-butt severity (0C) Burnt bottom progression and Figure 9
Figure 10

Claims (1)

[Claims] a first step of degreasing an insulating substrate formed of a material containing glass particles in an oxidizing atmosphere at a temperature higher than the softening temperature of the glass particles and lower than the sintering temperature; a second step of forming a thick film substrate by printing a circuit pattern including a conductor layer made of a base metal material on the substrate; and a plurality of thick film substrates formed in the second step after this second step. and a fourth step of simultaneously firing the plurality of laminated thick film substrates in an inert atmosphere after the third step. A method for manufacturing a thick film substrate.