JPS5928054B2 - Substrate for hybrid integrated circuits - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a substrate used in a semiconductor device, particularly a hybrid integrated circuit. The present invention relates to a substrate suitable for.

In general, the face-down bonding method uses protruding solder parts formed on either or both of the connection area on the substrate and the electrode on the semiconductor chip, with the substrate surface and the main surface of the semiconductor chip facing each other. After bringing them into contact, they are simultaneously heated and cooled to electrically connect the connection area on the substrate and the electrode on the semiconductor chip via the solder portion, and to fix the semiconductor chip on the substrate. This method is widely used as an effective connection method for improving the performance and degree of integration of semiconductor devices, especially hybrid integrated circuits, simplifying manufacturing processes, and increasing yield.

As shown in FIGS. 1a and 1b, a board conventionally used in this type of connection method includes a board body 1 made of an insulating material such as alumina, and a conductive pattern 2 made of Pd or Au. is formed into a predetermined shape, and a glass film 3 made of a material such as glass frit is formed to surround the circumferential surface of the conductive pattern 2 except for the plurality of connection areas. A protruding solder portion 4 is formed in each of the upper connection regions to protrude beyond the glass film 3.

Note that the solder portion 4 usually contains 40% Sn and 60% Pb.
% solder is used. However, in such a board, since the solder portion 4 in the connection area formed on the conductive pattern 2 is surrounded by the film 3 that does not wet with solder, the protrusion shape increases by the thickness of the film 3 that does not wet with solder. The solder portion 4 becomes substantially lower.

Normally, when glass frit is used as the conductive pattern 2, it has a thickness of about 10 to 30 μm, and when the glass frit is fired, it sag on the solder part 4 of the connection area, which increases the variation in the area of the connection area. As a result, the height of the solder portion 4 varies, resulting in a decrease in yield and reliability. In addition, since the lower part of the solder part 4 is lower than the film 3 that does not wet with solder, flux is normally used for the connection area when forming the solder part 4, but the surface of the connection area is not activated sufficiently, causing differences in solder wetting, and causing variations in the solder portions 4. Furthermore, after connecting semiconductor chips, in order to confirm the connection state, observation is usually performed using a stereomicroscope in parallel with the board body 1, but in this case, the connection area is observed using a film that does not get wet with solder. There were drawbacks such as making it difficult to use. In view of the above points, the present invention has been made to solve such problems and eliminate such drawbacks.The main purpose of the present invention is to prevent solder wettability from being poor due to the influence of the glass film surrounding the connection points. It is an object of the present invention to provide a hybrid integrated circuit board that can prevent such problems from occurring.

Another object of the present invention is to reduce variations in the height of solder parts having protrusions formed in connection areas of conductive patterns, and to reduce variations in the shape of solder parts suitable for face-down bonding. It is an object of the present invention to provide a substrate for a hybrid integrated circuit, which can be formed without any problems, and which can improve yield and reliability as well as improve workability. In order to achieve such an object, the present invention provides a solder portion having a protrusion in a connection area on a conductive pattern formed on the main surface of an insulating substrate body, and a solder portion that surrounds the solder portion. A glass film formed on the solder portion is provided, and the solder portion is formed such that a lower portion thereof is located higher than the glass film. Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIGS. 2a and 2b are a plan view of essential parts and a cross-sectional view taken along the line -5 showing an embodiment of the present invention, and in these figures, the same or equivalent parts as in FIG. 1 are designated by the same numbers.

In this embodiment, a metal film 5 that is easily wetted by solder is formed in the connection area of the conductive pattern 2 to have a thickness equal to or greater than that of the glass film 3, and a solder portion 4 is formed on this metal film 5.
It is formed into a protrusion shape by protruding. in this case,
The conductive pattern 2 is composed of commonly used Ag-Pd and P.
The solder wettability is improved by adding t or increasing the ratio of Ag. According to the substrate of the above embodiment, the solder portion 4 is formed in a protrusion shape in the connection area of the conductive pattern 2.
In order to reduce the variation in the height of the solder part 4 and to make it easier to wet the solder part 4, the shape of the solder part 4 can be formed without variation. Work efficiency can be improved because the connection status can be observed without being disturbed by areas that are not wetted by solder.

Further, it is possible to prevent the solder wettability from becoming poor due to the influence of the glass film attached around the connection point. FIGS. 3a and 3b are a plan view of main parts and a sectional view taken along the line 1--1 of the same, showing another embodiment of the present invention, and in these figures, the same or corresponding parts as in FIG. 2 are designated by the same numbers.

The difference in this embodiment from the above is that a glass film 3 is provided at a location corresponding to each connection area of the conductive pattern 2.
By forming a base film 6 made of metal or insulating material with a film thickness equal to or greater than that of the base film 6, and lifting the connection area by this base film 6, a protrusion-like shape formed in the connection area is formed. The solder portion 4 is formed higher than the glass film 3. In this case, the base film 6 may be made of the same material as the glass film 3 or the same material as the conductive pattern 2. Therefore, this embodiment also has the same effect as the above embodiment. As described above, according to the present invention, it is possible to prevent the solder wettability from deteriorating due to the influence of the solder film attached around the connection point, and also to It is possible to reduce the variation in the height of the solder part with protrusions, and it also becomes easier to wet with the solder, so the shape of the solder part suitable for face-down bonding can be formed without variation, improving yield and reliability. be able to.

Furthermore, since the connection state can be easily observed without being obstructed by the glass film, there is an effect that workability can be improved.

[Brief explanation of drawings]

1A and 1B are a partial plan view and a sectional view taken along the line IV of a conventional hybrid integrated circuit board, and FIGS. Line sectional view, Figure 3a
and b are main part plan views showing other embodiments of the present invention;
FIG. DESCRIPTION OF SYMBOLS 1... Board body, 2... Conductive pattern, 3... Glass film, 4... Solder part in connection area, 5...・Metal film that is easily wetted by solder, 6... Base film for lifting the connection area.

Claims (1)

[Claims] 1 An insulating substrate body, a conductive pattern formed on the main surface of this substrate body, a glass film formed so as to surround the connection area of the conductive pattern, and a glass film formed on the connection area of the conductive pattern. and a solder part electrically connected to the conductive pattern, the lower surface of the solder part being set at the same or higher height than the upper surface of the glass film on the conductive pattern. Circuit board.