JPS60160656A - Manufacture of hybrid integrated circuit - Google Patents

Abstract

PURPOSE:To reduce the solder intrusion of an electrode film by heating a substrate at a specific temperature or higher and forming the electrode film consisting of NiCr-Au on the surface of the substrate through a sputtering method. CONSTITUTION:NiCr atoms and Au atoms collide with a residual gas (mainly, steam) in a process of sputtering. Consequently, weakening adhesion between a thin-film 3 consisting of NiCr and a thin-film 4 composed of Au is strengthened in such a manner that the thin-film 3 consisting of NiCr and the thin-film 4 composed of Au mutually diffuse by heating the temperature of a substrate at 250 deg.C or higher and a diffusion layer 6 for NiCr and Au is formed. Accordingly, the solder intrusion section of an electrode film consisting of NiCr-Au formed through a sputtering method can be reduced to the same extent as an electrode film shaped through a vacuum evaporation method.

Description

DETAILED DESCRIPTION OF THE INVENTION (al) Technical Field of the Invention The present invention relates to a method for manufacturing a hybrid integrated circuit, and in particular to a method for manufacturing a hybrid integrated circuit substrate, in which an electrode film made of NiCr-^U is formed on the surface of the substrate by sputtering. Regarding the manufacturing method.

(b) Background of the technology In manufacturing hybrid integrated circuits using thin films of tantalum (T112N) as resistors, solder is generally attached to the surface of the wiring pattern using a solder dip method, and the electrodes of the resistor and the wiring conductor are bonded to the surface of the wiring pattern. is formed.

Such a hybrid integrated circuit is required to have solder uniformly adhered to the surface of the wiring pattern, and there must be no portions where solder does not adhere (hereinafter referred to as solder cracks).

On the other hand, such a wiring pattern (hereinafter referred to as an electrode film) is generally made of a NiCr-Au thin film, and has conventionally been produced by a vacuum evaporation method. However, the electrode film produced by vacuum evaporation method lacks uniformity and has a problem of poor yield, and as sputtering equipment becomes faster, it has recently been replaced by sputtering method, which can produce a uniform electrode film. There is.

By replacing the vacuum evaporation method with the sputtering method to generate the electrode film, a uniform electrode film was obtained and the yield was improved; A new problem has arisen in that solder cracks tend to increase. Therefore, it is desired to establish a spackle strip 9 in which the solder cracks can be reduced to the same level as an electrode film produced by vacuum evaporation, and a uniform electrode film can be obtained.

TCI Prior Art and Problems Figure 1 is a cross-sectional view of a hybrid integrated circuit using a thin film of tantalum (Ta2N) as a resistor. This is a hybrid integrated circuit with cracked parts.

A resistor 2 made of Ta2N is formed on the surface of a substrate 1 made of ceramic or the like, and N is formed on both ends of the surface of the resistor 2.
An electrode film consisting of a thin film 3 of iCr and a thin film 4 of ^U has been produced. When the solder layer 5 is attached to such a substrate, the Au thin IJ4 diffuses into the solder layer 5, and the NiCr thin IJ4 diffuses into the solder layer 5.
Solder N5 will be directly attached on top of 1!3. Therefore, if the adhesion of the 11u thin film 4 to the NiCr thin McJ43 is strong, the thin film 4 of Fig. 1
As shown in 81, the NiCr thin film 3 and the solder layer 5 are in close contact with each other,
If the adhesion of the ^U thin film 4 to the NiCr thin film 3 is weak, the NiCr thin film 3 and the solder 1 layer 5 will not be in close contact with each other, and as shown in FIG.
As shown in b+, solder cracks occur.

Since electrode films are produced by vacuum evaporation in a high vacuum of 1O-6 Torr, NiCr atoms and A
Although the probability of U atoms colliding with residual gas is low, since electrode films are produced by sputtering in a relatively low vacuum of 1O-3 Torr, NiCr atoms and Au atoms collide with residual gas (mainly water vapor). !1 The probability of collision is high, and the adhesion between the NiCr thin film 3 and the ^U thin film 4 formed on the substrate becomes weak, and solder cracks are likely to occur.

fdl Object of the Invention The object of the present invention is to obtain NlCr-A produced by the spacking method.
8ilIy from u! An object of the present invention is to provide a method for manufacturing a substrate for a hybrid integrated circuit, which reduces solder cracks to the same level as an electrode film produced by a vacuum evaporation method.

tel Structure of the Invention This object is achieved by heating the substrate to a temperature of 250 DEG C. or higher to improve solderability, and forming an electrode film of NiCr--Au on the surface of the substrate using the spacing method.

if) Examples of the invention The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 2 is a diagram showing the relationship between the substrate temperature and defective rate due to solder cracking when processing the substrate, and FIG. 3 is a diagram for explaining the present invention in detail. According to Figure 2, the failure rate due to solder cracks in electrode films produced by vacuum evaporation is as high as about 50% when the substrate temperature is around room temperature, but it drops to zero when the substrate temperature is heated to around 150°C. . On the other hand, the failure rate due to solder cracks in electrode films produced by the sppack method is extremely high at approximately 90% when the substrate temperature is near room temperature, and the failure rate due to solder cracks in electrode films produced by the vacuum evaporation method is extremely high. Approximately 30% of defects occur even at temperatures near 150°C.

In order to completely eliminate this, it is necessary to heat the substrate temperature to 250° C. or higher.

This is caused by NiCr atoms and Au atoms colliding with residual gas (mainly water vapor) during the spuck process.
NiCr thin l that had become weak! Thin film 4 of l13 and ^U
When the substrate temperature is heated to 250°C or higher, the adhesion between the NkCr thin film 3 and the Au thin film 4 diffuses into each other, forming a group of NiCr and ^U diffused M6, as shown in Fig. 3. This is because it makes you stronger.

(gl) Effects of the Invention As described above, according to the present invention, the solder cracks of the NiCr-Au electrode film produced by the spuck method are reduced to the same level as those of the electrode film produced by the vacuum evaporation method. A method for manufacturing an integrated circuit substrate can be provided.

[Brief explanation of the drawings] Fig. 1 is a cross-sectional view of a hybrid integrated circuit using a thin film of tankur (Ta2N) as a resistor. Fig. 1 181 is a normal hybrid integrated circuit; A hybrid integrated circuit with solder cracks, FIG. 2 is a diagram showing the relationship between the substrate temperature during substrate processing and the defective rate due to solder cracks, and FIG. 3 is a diagram for explaining the present invention in detail. In the figure, 1 is a substrate, 2 is a resistor made of Ta2N, and 3 is a resistor made of Ta2N.
is a thin film of NiCr, 4 is a thin film of Au, and 6 is a thin film of NiCr and A.
The diffusion layer of u is shown.

Claims (1)

[Claims] In the production of hybrid integrated circuits, the temperature of the substrate is heated to 250°C or higher to improve solderability, and an electrode film made of NiCr-8U is formed on the surface of the substrate by sputtering. Method of manufacturing circuits.