JPS5937579B2 - Semiconductor device with metal protrusions - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In recent years, a wireless bonding method has been attracting attention in place of the conventional wire bonding method as a means for electrically connecting an electrode terminal provided on a semiconductor element to an external terminal.

This wireless bonding method allows a large number of electrode leads, which are external terminals, to be connected to the electrode terminals at once (so-called gang bonding), so mass production and improved reliability can be achieved. There are various wireless bonding methods, but the present invention involves forming metal protrusions on the electrode terminals of a semiconductor element via a barrier metal, and heating and pressurizing the metal protrusions and external lead terminals. The present invention relates to a semiconductor device used in a film carrier method, etc., which is connected by a wire.

First, the structure and manufacturing method of a conventional device in which metal protrusions are formed on a semiconductor element will be explained with reference to FIG.

An aluminum wiring pattern is provided on a semiconductor element 2 having a thermal oxide film, and this aluminum wiring pattern is connected to an aluminum electrode terminal 3 made of the same material. Further, in order to protect the aluminum wiring pattern, a CVDSiO2 film 4 is deposited on the entire surface, and holes are formed only on the aluminum electrode terminals 3 by photolithography. Next, a barrier metal 5 consisting of multiple layers of Cr-Cu, etc. is formed by continuous vacuum deposition, and this barrier metal is used as a plating electrode to selectively coat metal protrusions 6 of Au, Cu, etc. with a thickness of 10 to 30 μm. Form to height. Then, the barrier metal 5 is selectively removed, and the semiconductor device shown in FIG. 1 is formed. Next, by aligning the metal protrusion 6 and, for example, the Sn-plated Cu lead terminal 11, and applying pressure and heat, if the metal protrusion is Au, contact will be established due to the Au-Sn eutectic. The area near the surface is alloyed, and mechanical and electrical connections to the outside can be obtained as shown in Figure 2.

However, due to this pressurizing and heating process, significant pressure is applied to the metal protrusion 6.

In this case, the flat area of the metal protrusion 6 is 30 x 50.
A pressure of approximately 20V is required for a diameter of about μm. That is, a pressure of 9/cwi is applied to 1300. This pressure is applied to the metal protrusion 6 in the vertical direction 12,
Pressure is applied in the lateral direction 13 of the metal protrusion 6 by the horizontal base of the pressing jig or the horizontal base of the lead terminal 11 . According to the inventors' study, in the case of the former pressure, CVDS
It was found that the iO film 4 was caught between the metal protrusion 6 and the electrode terminal 3, causing cracks 6'. Furthermore, in the case of the latter pressure, the metal protrusion 6 forces (deforms) the soft electrode terminal 3 in the lateral direction, thereby causing it to become hard (°CVD
A crack 6'l)1 occurs in the SK)2 film 4. and,
If a corrosive solution enters from the outside through the crack 6', the electrode terminal 3 under the metal protrusion 6 will be corroded, which will not only significantly reduce the adhesion strength of the metal protrusion 6 but also cause electrical failure. It also resulted in the occurrence of

The present invention actively prevents cracks in the CVDSiO2 film caused by pressure during connection with external leads, and provides a semiconductor device having highly reliable metal protrusions.

A semiconductor device and a method for manufacturing the same according to an embodiment of the present invention will be explained with reference to FIG.

An aluminum wiring pattern (not shown) is formed on an oxide film 22 provided on a semiconductor substrate 21 made of Si or the like on which semiconductor elements (not shown) are formed in order to electrically connect each functional element group formed in the semiconductor substrate 21. ) is formed, and the aluminum wiring pattern at the end of the substrate 21 becomes the electrode terminal 23.
Next, a CVDSiO film 24 is deposited on the entire surface of the aluminum wiring pattern to electrically or mechanically protect it, and a film 24 made of CVDSiO is deposited on the entire surface of the electrode terminal 23 using photoetching to form a film larger than the terminal 23 for connection with the outside. CVDSiO2 film 2
An opening 25 is formed in 4 (FIG. 3A, b).

Next, a barrier metal layer 26 made of Cr-Cu, Cr-Ni, etc. is continuously formed on the entire surface including the openings 25 by vacuum evaporation, and the barrier metal layer 26 is formed on the entire surface including the openings 25 by photolithography. The barrier metal layer 26 is left in a large area (FIG. 3C, d).

Through this step, the entire area of the electrode terminal 23 and the CVDSiO2
A barrier metal layer 26 is formed to cover a portion of the film 240. Next, by selectively forming metal protrusions 27 of Au, Cu, etc. on the barrier metal layer 26 by electrolytic plating, the structure shown in FIG. 3e can be obtained.

With the configuration as shown in FIG. 3e, there is no CVDSiO2 film interposed between the metal protrusion 27 and the electrode terminal 23, and the connection between the external lead and the metal protrusion is prevented as explained in FIG. CV due to deformation of the electrode terminal 23 that occurs during
No cracks occur in DSiO2. Therefore, corrosion of the electrode terminals 23 connected to the aluminum wiring pattern does not occur, so that there is no reduction in the strength of the metal protrusions and reliability due to electrical defects. As mentioned above,
Since the present invention does not have an insulating film on the electrode terminal portion, it is possible to eliminate the occurrence of cracks in the protective insulating film, and this invention greatly contributes to semiconductor devices having metal protrusions.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional semiconductor device with metal protrusions, and Figure 2 is a conventional configuration with CVDSiO generated during bonding.
, a sectional view showing corrosion of an electrode terminal due to cracks in the film, and FIG. FIG. 21... Semiconductor substrate, 22... Oxide film, 23... Electrode terminal, 24... CVD
SiO, membrane, 25...opening, 26...
- Barrier metal layer, 27...metal protrusion.

Claims (1)

[Claims] 1. An insulating film that protects an Al wiring pattern formed on a semiconductor element has an opening larger than an electrode terminal portion of the Al wiring pattern near the electrode terminal portion, and
A metal protrusion formed in the vicinity of the aperture, wherein a region of the barrier metal is larger than the aperture, and a contact surface between the metal protrusion and the barrier metal is smaller than the aperture. A semiconductor device that has an object.