JPS6377196A - Manufacture of copper cladded multilayer board with glazed resistor - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing a copper multilayer substrate with a glazed resistor on which semiconductor ICs, chip components, etc. are mounted and interconnected.

Conventional technology Conductor paste materials used in ceramic wiring boards have traditionally been made of noble metals such as Au and Au-Pt.

Ag-Pt, Ag-Pd, etc. are W as base metals.

There are high melting point metals such as Mo and Mo-Mn. The former Au,
Noble metal pastes such as Au-Pt, Ag-PL, and Ag-Pd can be baked in air and are highly reliable, but have the problem of high cost. Also, the latter W
, Mo, Mo-Mn and other high melting point metals are around 1600℃,
That is, since the temperature is higher than the green sheet sintering temperature (approximately 1500° C.), it is easy to form multiple layers because they are fired simultaneously, but it is dangerous because the electrical resistance is high and it is necessary to fire in a reducing atmosphere. Furthermore, since it cannot be directly soldered, it is necessary to plate the conductor surface with Ni or the like, which is the reason why it is not widely accepted in the industry.

Therefore, in recent years, attention has been focused on Cu, which is inexpensive, has low electrical resistance, and has good solderability, and efforts are being actively made in various fields to put it into practical use. Here, a method for manufacturing a ceramic wiring board using Cu paste will be described. Screen printing is performed using Cu paste on a sintered substrate such as alumina to form a wiring pattern, and after drying, the Cu is not oxidized at a temperature below the melting point of Cu and the organic binder in the conductor paste is fully absorbed. The process involves firing in a nitrogen atmosphere with controlled oxygen partial pressure so that it is decomposed and removed. Furthermore, in ceramic multilayer substrates using Cu paste, an insulating paste is further printed, and the Cu paste described above is printed.
The paste and insulating paste are printed and fired repeatedly to form multiple layers.

Problems to be Solved by the Invention However, multilayer substrates using Cu paste generally have the following problems. That is, in order to obtain a Cu''Q electrode, it is necessary to perform firing in nitrogen, so resistors and dielectrics are sufficiently stable even in nitrogen.

Overcoat material is required. However, the current situation is that there are not enough of these materials, and the development of these materials that can be fired with nitrogen is actively being carried out in various fields. Especially for resistors, new types of material systems that do not use RuO□ have been proposed. (Donna Elle
huff key. Clark Kay Finsher Aiiiiiii.

Transactions on Components, Hybrid and Manufacturing Technology 1
984, December CHMT-7No. 4 (DAN
A L, RAN KEY and CLA
RKK.

FISHERJEERTRANSACTIONS O
F COMPONENTS.

1 (YBR[DS AND”MUNUTACTIJR
ING TECHNOLOGY, VoLCHMT
-7, No, 4. DECEMBER1984)
.

However, these materials also have some problems. Firstly, because it uses a special material system, it is difficult to cover the entire area where sheet resistance is required (10 Ω/mm to IM Ω/mm), and it is difficult to cover only the lower resistance range, or the upper resistance range. Furthermore, when baking the resistor paste, it is difficult to remove the organic binder in the paste. Residual binder then remains in the form of carbon and prevents melting of the glass in the resistor paste, resulting in insufficient resistor formation. Because of the problems mentioned above, it is thought that it will take many years before it can be put into practical use. Therefore,
Some of the following methods have been proposed. All Ru○2 materials, which are most commonly used in air firing, are fired in advance in the air, and then at a low temperature (550 to 600℃).
) The electrodes are formed using a Cu paste that can be fired. (Christopher Niss International Microelectronics Conference 1982 Proceedings fi Chris
topher R, S, NeedsInter
national Microelectronics
Conference 982 Proceedings
ings).

According to this method, Ru○2, which is very stable in air,
A Cu electrode is formed using a paste at a temperature below the temperature at which RuO□ is reduced in nitrogen (600° C.), and can be said to be a combination of the good aspects of both a RuO□ resistor and a Cu electrode. However, there are also problems. This is because the firing temperature of the Cu electrode that will be fired later is the normally used temperature (approximately 90°C).
0°C), the adhesive strength is weak.

Means for Solving the Problems In order to solve the above-mentioned problems of Cu hybrid ICs with added glaze resistors, the present invention uses Ru 02 resistor paste, performs firing in air, and then uses Cu electrode paste. The electrode portion and circuit pattern of the glaze resistor are printed using the glaze resistor.

Then, a via section is formed using an insulating paste mainly composed of powder mixed with glass and ceramic with a softening point of 600 degrees Celsius or less so that the glaze resistor part is not exposed to the outside and the circuit pattern can be connected to the upper part. The entire surface is printed except for the parts to be printed, and fired in N2 at a high temperature (800°C) or higher.Finally, a pattern is printed on the upper layer with Cu paste,
Similarly, N2 firing is performed at a high temperature.

Function: By using the insulating paste having the above-mentioned structure, the present invention can protect R u O2, which is reduced at high temperatures, from the N2 atmosphere and increase the adhesive strength of Cu. That is, after printing Cu electrodes on a glazed resistor that has been fired in air, it is covered with an insulating paste, and when it is fired in N2, the glass component in the insulating paste softens at around 600°C, sealing the glazed resistor. Ru
Resistor components such as O2 are not reduced. Then, it is further held at a high temperature to metallize the Cu, simultaneously crystallize the insulating material and sinter it by reacting with ceramics such as alumina. Furthermore, a Cu paste is printed and fired on the top layer. At this time, the insulating material does not soften because it has a high softening point due to crystallization or reaction with the ceramic.

C with glazed resistor of the present invention obtained as above
The u-hybrid IC features high precision resistance formation, high reliability,
Not only can you use Cu as is (low TCR, etc.), but you can also sinter Cu at high temperatures, making it highly reliable.
U metallization can be obtained. Furthermore, by repeating printing or printing and firing of Cu paste and insulating paste a desired number of times, multilayering can be easily achieved. An example will be described below.

Example 9 RuO shown in Table 1 was applied to the surface of a 6% Al2O3 substrate.
The □-based resistance paste was printed on a screen with a 250 mesh and 5 μm emulsion thickness, and after drying at 120°C for 10 minutes, it was heated in a mesh belt furnace at 850°C (peak 10 minutes).
Fired in air. This state is shown in FIG. 1+a+. In the figure, 1 is an alumina substrate, and 2 is the resistor.

(Margins below) Table 1: Resistance paste fired film thickness used: 12.5 μm Next, using Cu paste (#9153 manufactured by DuPont), a 350 mesh screen with an emulsion thickness of 5 μm was used.
I printed it. The state is shown in Fig. 1 (bl). In the figure, 3 is the Cu electrode. Further, borosilicate glass (#7059 manufactured by Corning) was crushed to have an average particle size of 1.8.
50,150 wt % of alumina (average particle size: 0.3 μm) powder was mixed and kneaded with a solvent containing an organic binder using a three-stage roll to form a paste. Then, this insulating paste is printed so as to cover the resistor portion, leaving a predetermined via forming portion. The printing conditions are 25
The emulsion thickness is 10 μm. At this time, in order to completely protect the resistor from the N2 atmosphere, it is preferable to repeat printing two or more times to reduce the probability of phenomena such as pinholes during printing. Firing was performed in nitrogen (0□ amount 1100 pp or less) at 900° C. on a mesh belt with a peak time of 10 minutes. Its cross section is shown in FIG. 1fcl. At this time, it is better that the 02'tQ degree is as low as possible, but in consideration of the decomposition of the organic binder and the metallization of Cu, it is most preferably about 10 to 50 ppm. Then, the same Cu paste as above is used to form an electrode in the uppermost layer. Printing and firing conditions are the same as above.

Figure 1 + dl is a cross-sectional view of the substrate obtained as described above.
Shown below. 4 is the insulating layer, and 5 is the uppermost Cu layer. Then, a comparison was made with the resistance characteristics of the resistor shown in Table 1 produced by a conventional method. In the conventional method, an Ag/Pd electrode is printed and fired (in air), and then the resistance paste is printed and fired (in air), and the structure thereof is shown in FIG.

The comparison results are shown in Table 2.

(Margin below) As is clear from the table, it can be seen that the same performance can be obtained when compared with the resistance characteristics treated in air. Also, the metallization property of Cu is 96% Aj! It was found that a product equivalent to that obtained when formed on No. 208 was obtained. Table 3 shows the results.

Table 3: Cu metallization properties of the uppermost layer In the present invention, borosilicate glass was used as the insulating paste.
Needless to say, it is sufficient that the material has a softening point of 00° C. or lower and does not contain components that are reduced in a nitrogen atmosphere at 600° C. or higher. Further, although alumina is used as the ceramic material, it goes without saying that any material that reacts with glass and has a high softening point when fired at about 900° C. may be used.

Effects of the Invention The present invention provides an effective method for adding a high reliability glaze resistor to a hybrid IC using Cu and a Cu multilayer substrate. In other words, since the glazed resistor can be sealed with the insulating paste, Cu can be baked at high temperature without deteriorating the glazed resistor due to the atmosphere, and this is significantly effective in improving the metallization properties of Cu.

Furthermore, since multilayer formation can be performed simultaneously, this invention is extremely effective.

[Brief explanation of the drawing]

FIG. 1 (al is a cross-sectional view after forming a glazed resistor in the Cu hybrid IC with a resistor obtained by the present invention, and FIG. 1 Cb is a cross-sectional view after printing the same Cu electric scraper,
Fig. 1 (C1 is a cross-sectional view after further forming an insulating layer, Fig. 1 fdl is a cross-sectional view after forming an upper layer of Cu, Fig. 2 is a cross-sectional view after forming an upper layer of Cu, and Fig. 2 is a cross-sectional view after forming an insulating layer.
) is a schematic diagram of the product produced by the method. 1... Alumina substrate, 2... Glaze resistor, 3... Cu electrode, 4... Absolute 1
E layer, 5... Cu top layer electrode, 6...
Ag/Pd electrode, 7...glaze resistor. Name of agent: Patent attorney Toshio Nakao and one other person -N (Y'
) Dimensions＼ to , 〜 −＼
() Mi○J −~ L′), 錕″ regret

Claims (1)

[Claims] Printing a glazed resistor paste containing at least a conductor powder, a glass powder, and an organic binder on a sintered ceramic substrate, firing it in air, and using a copper paste on the glazed resistor-formed substrate, The terminal electrode portion and circuit pattern of the glaze resistor are printed, and then 60
An insulating paste mainly composed of a mixed powder of glass and ceramic filler with a softening point below 0°C is used to prevent the surface of the glazed resistor from being directly exposed to the outside, and to form a via hole that can be connected to a desired part of the copper circuit pattern. The above-mentioned copper paste printing and the above-mentioned insulating paste printing are repeated a predetermined number of times, followed by baking at a temperature of 800 ° C. or higher in a nitrogen atmosphere with an oxygen concentration of 100 ppm or less,
Further, a copper multilayer board with a glazed resistor is characterized in that the uppermost layer of the fired board is printed using copper paste, and fired at a temperature of 800° C. or higher in a nitrogen atmosphere with an oxygen concentration of 100 ppm or lower. manufacturing method.