JPS63313839A - Semiconductor device - Google Patents

Abstract

PURPOSE:To enable a highly stable connection structure to be manufactured at low cost by a method wherein an electrode part composed of an aluminum layer, a bonding layer comprising a material to convert an aluminum oxide into a conductive oxide, a gold layer and a silver paste is provided on the surface of a semiconductor substrate. CONSTITUTION:An Al electrode 2, a bonding layer 3 formed on the Al 2 and Au 4 are provided on a substrate 1. By using e.g. Cr 3 as the bonding layer 3, the surface of Al 2 is protected from oxidation and simultaneously a thin oxide film is varied from the composition of AlO to AlO-Cr as a conductive oxide by the free oxide producing energy of Cr. Finally, when Au 4 is coated with silver paste, the contact resistance is not increased even if Au 4 is supplied with additional current. Through these procedures, highly reliable semiconductor device can be manufactured at low cost.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention improves the structure of the electrode part that outputs electrical signals from semiconductor elements such as ICs, LSIs, Runsisters, and diodes. The present invention relates to a semiconductor device.

(Prior art) Conventionally, when extracting signals from a semiconductor element, there have been methods such as bonding an Au wire to an aluminum electrode formed on the semiconductor element, and TAB, which forms a pad with Au plating on the electrode and thermocompresses the lead. There are many ways to call it.

These methods require space to take out the leads from the IC and attach them to the board, and the site area becomes several times larger than the size of the IC.

For example, FIG. 4(a) shows wire bonding, where the IC size is A and the site area is B. Figure 4(b) shows the case of TAB and similarly I
The size of C is the area of A1 site.

In both cases, B is twice as large as A).

As a method that does not have such problems, there is also a method of forming solder as bumps on the IC. In such a method, since the substrate and the IC are firmly bonded, stress due to thermal expansion is often applied unevenly, and there are many problems with connection reliability.

A method of directly wiring the IC has also been proposed as a method to solve the above-mentioned problems. One way to do this is to embed an IC in a plastic sheet.
Another method is to directly wire the electrodes.

The problems with such a method are 1. Since the surface of the υ electrode is oxidized, ohmic contact cannot be made between the 1M electrode and the silver paste, resulting in a problem of increased resistance and a large voltage drop in the signal, often resulting in inoperability.

(Problem to be Solved by the Invention) As a method for solving this problem, a method of bonding an Au pole onto the M electrode has also been proposed. but,
This method has the problem that the work of bonding the Au balls is complicated and expensive.

The present invention proposes a semiconductor device having a low cost and highly reliable connection structure in order to solve such problems.

[Structure of the invention]

(Means and effects for solving the problems) The present invention provides si
Cr/Au on the AJ electrode on the substrate.

Cr/Pd/Au, Ti/Au, Ti/Pd/Au
After forming layers of , Ti/Ni/Au, Cr/Pd/Au, a semiconductor having electrodes connected to the surface with silver epoxy paste is used. This conversion results in a low-cost and highly reliable semiconductor device.

(Example) Embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, a substrate 1 is provided with semiconductor elements such as St and GaAs. On this element, Cr(3) and A are formed on the υ electrode (2) and M(2).
u (4) is provided.

Instead of Cr0, TI% or Pd, Ni, etc. may be inserted between Cr and Au or between Ti and Au0 as a diffusion prevention layer between Au and the adhesive layer.

Such combinations of adhesive layer, diffusion prevention layer and Au such as Cr/Au, Cr1/Au, Ti/Au, Ti/P
d/Au.

Metalizations such as T 1 /N i /Au, Cr/P d /Au, etc. are well-known metallizations.

However, by forming T1 or Cr on the M electrode of the semiconductor element, method 1. At the same time, it protects the surface of υ from oxidation, and even with a thin oxide film, due to the free energy of oxidation of Cr, the shape of Alto-C is changed from Alo to Alto-C.
r or AI! -0-TI changes into a conductive oxide,
It becomes highly reliable.

Figure 2 shows a cross section of the pole part. Also, at the same time.

The gold and silver paste come into contact and become stable. This change in contact resistance is shown in Figure @3. FIG. 3 shows a comparison between the case where silver paste is attached to the #'i, AI* electrode and the case where silver paste is attached to the Au electrode.

When the silver paste is attached to the AI electrode, the contact resistance increases as the current increases, whereas when the silver paste is attached to the Au electrode, the contact resistance does not increase. In this way, Cr/Au with A11 as the pole.

Cr/N i/Au , T i/Au , T i/Pd
/Au, T i/N1/Atr.

Methods for applying Cr/Pd/Au include vapor deposition, sputtering, and ion blasting. Photolithography can be used to shape the pad.

The thickness of Cr and T1 actually used was 50 nm to 500 nm.
m, the thickness of Ni and Pd is 0 to 500 mm. As in the case of TAB and wire bonding,
This shows that there is no need to increase the thickness of the gold and shows how the invention saves resources.

〔Effect of the invention〕

According to the present invention, a semiconductor device having a highly stable connection structure can be constructed at low cost.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing the main parts of an embodiment of the present invention, and FIG.
The figure is a partial sectional view showing another embodiment of the present invention, FIG. 3 is a curve diagram explaining the present invention in detail, and FIG. 4 is a plan view showing a conventional semiconductor device. l...Substrate, 2...11% 3...Cr, '4
...Aug1 agent Patent attorney Nori Chika Ken Yudo Mitsuyuki Matsuyama rlJe Tsune-AL! To personal current

Claims (7)

[Claims] (1) an aluminum layer provided on the surface of the semiconductor substrate and forming part of the electrode; an adhesive layer provided on the surface of the aluminum layer and made of a substance that converts an oxide produced by oxidation of aluminum into a conductive oxide; A semiconductor device characterized by comprising an electrode portion comprising a gold layer provided on the surface of the adhesive layer and a silver paste provided in contact with the gold layer to extract electricity. (2) The semiconductor device according to claim 1, wherein the gold layer is formed to have a thickness of 50 to 500 nm. (3) The semiconductor device according to claim 1, wherein the adhesive layer is made of any one of chromium, titanium, and vanadium. (4) The semiconductor device according to claim 3, wherein the adhesive layer is formed to have a thickness of 50 to 500 nm. (5) The semiconductor device according to claim 1, characterized in that a diffusion prevention layer is provided between the adhesive layer and the gold layer. (6) The semiconductor device according to claim 5, wherein the diffusion prevention layer is made of nickel or lead. (7) The semiconductor device according to claim 6, wherein the diffusion prevention layer is formed to have a thickness of 0 to 500 nm.