JPH0558201B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to an improvement in an insulating layer material suitable for use in an insulating layer of a thick film multilayer substrate using a copper-based conductive paste. [Technical Background of the Invention] As is well known, in recent years, hybrid integrated circuits have come into widespread use in order to reduce the size and weight of electronic devices and the like. This hybrid integrated circuit is
For example, it is constructed by soldering chip-type passive elements and active elements to a thick film substrate made of an insulating substrate made of a ceramic material such as alumina, and then printing and firing conductive materials and resistance materials to form a wiring layer. It is something that Recently, in order to reduce the size and weight of electronic devices, there has been a demand for even higher densities, and the above wiring layers are now formed in multiple layers with insulating layers interposed in thick film substrates. . In recent years, copper-based conductor paste has been used as the conductor material instead of the conventionally commonly used silver-palladium-based conductor base, improving electrical characteristics and reliability. Moreover, consideration has been given to making it economically advantageous. A thick film multilayer board using such a copper-based conductive paste is manufactured as follows. first,
A ruthenium oxide-based resistance paste is printed on an insulating substrate made of ceramic material using a screen printing method, and then baked in air at a temperature of approximately 850°C to form a resistor layer. After that, it is manufactured by printing and firing a copper-based conductive paste and a glass-based insulating paste so as to be alternately laminated. In this case, the firing of the copper-based conductive paste and the glass-based insulating paste must be carried out in an inert gas, such as nitrogen gas, to prevent oxidation of the copper. In order to suppress the resistance value fluctuation of the above resistor layer, approximately 600
It becomes necessary to carry out the process at a low temperature of about ℃. For this reason, materials containing a large amount of lead oxide (PbO) have generally been developed as materials (glass compositions) for insulating pastes that can be fired at low temperatures as mentioned above. If fired inside, lead will precipitate and the insulation performance will deteriorate significantly, making it unsuitable for practical use. Therefore, there has been a demand for lead-free glass compositions for insulating layers that can be fired at low temperatures of about 600°C. A method has been developed in which a composition for low-temperature firing, which has a crystallization temperature of 650°C, is fired near the crystallization temperature. [Problems in the background art] However, completely crystallized glass as described above is relatively prone to pinholes, poor insulation between the upper and lower wiring layers, and the upper wiring layers are not in close contact with each other. It has the problem of being difficult. Furthermore, a glass composition having such a composition has the disadvantage that the wettability of alumina to the insulating substrate is not good and the adhesion is insufficient. [Purpose of the Invention] This invention was made in consideration of the above circumstances, and has excellent insulation performance and adhesion, can be fired at a low temperature, and does not significantly change the resistance value of the resistor layer that has already been formed. The purpose is to provide a good material for an insulating layer. [Summary of the Invention] That is, the insulating layer material according to the present invention contains 5 to 20% by weight of SiO ₂ , 45 to 60% of ZnO, and 45 to 60% of B ₂ O ₃ by weight.
15-30, R ₂ O (Li ₂ O + Na ₂ O + K ₂ O) 0.1-3,
Al ₂ O ₃ 0.5-5, Bi ₂ O ₃ 0.5-5, F 0.5-2,
SnO ₂ from 0.5 to 2, CoO from 0 to 2, P ₂ O ₅ from 0 to 2,
ZrO ₂ is blended in a ratio of 0 to 5, CdO is 0 to 5, and PbO is blended in a ratio of 0 to 3 to give a crystallization temperature of 650 to 750°C. Here, the reasons for limiting each component to the above-mentioned mixing ratio are as follows. SiO ₂ : If it is less than 5%, the viscosity during melting will be low;
Hard to vitrify. Moreover, if the amount is more than 20%, the softening temperature will increase, making it impossible to fire at low temperatures (600°C). ZnO: If it is less than 45%, crystallization will not be possible,
If it exceeds 60%, the crystallization temperature will drop too much. _B2O3 : If it is less than 15% _, the softening temperature will be high,
If it exceeds 30%, sufficient crystallization will not be possible. R ₂ O: Li ₂ O, to promote glass melting;
One or more of Na ₂ O and K ₂ O can be added, but if the total amount exceeds 3%, the insulation resistance value will decrease. Al ₂ O ₃ : If it is less than 0.5%, the crystallization temperature will be too low, and if it is more than 5%, the softening temperature of the glass will be too high. Bi ₂ O ₃ : If it is less than 0.5%, the wettability of the glass to the alumina substrate will be poor, and if it is more than 5%, the expansion coefficient will become too large. F: Added to promote melting of glass,
If it exceeds 2%, the expansion coefficient becomes large. SnO ₂ : Added to improve the water resistance of glass. If it is less than 0.5%, there is no effect, and if it is more than 2%, the effect does not improve. For CoO, _P2O5 , _ZrO2 , CdO, _PbO ,
Although they are not essential components, if one or more of them are included at 0.1%, the insulation resistance will not deteriorate.
It contributes to maintaining the stability of the glass, but if it exceeds 2, 2, 5, 5, or 3%, the glass becomes inhomogeneous, the insulation resistance deteriorates, or no increase in effectiveness can be expected. Furthermore, in order to promote the melting of glass,
Although RO (MgO, CaO, BaO, SrO) components are often added, in this invention, the addition of RO components reduces the adhesion of the conductor on the glass insulating layer, so it is not added. [Embodiment of the Invention] An embodiment of the invention will be described below.
That is, the raw materials are mixed to have the composition shown in Table 1. In addition, in Table 1, sample number (1)
Sample numbers (4) and (5) indicate conventional insulating layer materials, respectively. Then, the mixture prepared as shown in Table 1,
It is melted and vitrified in a platinum crucible at a temperature of 1300-1400℃. Next, this glass is crushed and sieved, and then crushed by a wet method to obtain a powder having an average particle size of 5 μm. Then, this powder is kneaded with an appropriate amount of vehicle (for example, terpineol of ethyl cellulose) to form a glass paste. After that, the glass paste is printed so as to cover the first layer, which is a wiring layer made of a copper-based conductor and a ruthenium oxide (RuO ₂ )-based resistor, which has been previously formed on the alumina substrate by printing and firing, An insulating layer with a thickness of about 40 μm is formed by baking at 600° C. for 10 minutes in a nitrogen gas atmosphere. Then, a copper-based conductor that will become a second wiring layer is similarly formed on this insulating layer. Since the above-mentioned glass composition for the insulating layer is fired at a low temperature of 600°C, the insulating layer can be formed without being completely crystallized, and pinholes do not occur as in the conventional method. It is possible to improve insulation properties. The physical properties of the glass composition produced as described above, the insulation resistance value of the insulating layer formed, the adhesion of the insulating layer to the alumina substrate surface, the solder wettability of the copper-based conductor on the insulating layer, etc. are shown in Table 2. Shown below. In this case, the insulation resistance was determined by applying 50 V DC between each conductor of the first wiring layer and the second wiring layer after leaving it in a constant temperature and humidity chamber at 60°C and 95% for 1000 hours. This is the resistance value at room temperature. In addition, adhesion can be determined by soldering a lead wire to the second layer conductor and pulling it vertically. When the peel strength was measured, a value of 1 Kg/mm ² or more was considered good. Furthermore, the solder wettability was determined by Pb containing 2% Ag.
-Sn eutectic solder was used, and the sample was immersed at 230°C for 3 seconds and then pulled up. If 90% or more of the second layer conductor area was wet with the solder, it was judged as good. Here, in the above embodiment, it was explained that the copper-based conductor was fired in an inert gas atmosphere.
It goes without saying that the insulating layer material according to the present invention can also be applied to, for example, a thick film multilayer substrate in which a silver-palladium conductor is fired in air.

【table】

〔Effect of the invention〕

Therefore, as detailed above, according to the present invention, an extremely good material which has excellent insulation performance and adhesion, which can be fired at a low temperature, and which does not significantly change the resistance value of the resistor layer that has already been formed, can be obtained. A material for an insulating layer can be provided.

Claims (1)

[Claims] 1% by weight, SiO ₂ 5-20, ZnO 45-60,
B ₂ O ₃ is 15-30, R ₂ O (Li ₂ O + Na ₂ O + K ₂ O) is 0.1
~3, Al ₂ O ₃ 0.5 ~ 5, Bi ₂ O ₃ 0.5 ~ 5, F
0.5-2, SnO ₂ 0.5-2, CoO 0-2, P ₂ O ₅
0-2, ZrO ₂ 0-5, CdO 0-5, PbO
A material for an insulating layer, characterized in that the material is blended in a ratio of 0 to 3 to have a crystallization temperature of 650 to 700°C.