JPS63110749A - Semiconductor device - Google Patents

Abstract

PURPOSE:To maintain an electrically stable connection by a method wherein a reaction between a silicide layer and an Al alloy layer is suppressed in such a way that a reaction-suppressing layer is formed between the Al alloy layer and the silicide layer. CONSTITUTION:After a silicon oxide film 4 is formed on an Si substrate 5, a refractory metal silicide 3 is coated and is processed so that a desired pattern 3 as an under-layer wiring part can be obtained by photoetching. In addition, after an insulating film 4' is coated and formed, an opening 6 is made. Then, a retractory metal nitride layer 2 and an Al alloy layer 1 are piled up as an upper-layer wiring part, and these are processed to form a prescribed pattern. Because the refractory metal nitride is an electric conductor and a very stable compound, it does hardly react with an Al alloy and a refractory metal silicide during a heat-treatment process which is required for the manufacture of a semiconductor device, and its stable structure can be maintained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a semiconductor device, and particularly to a semiconductor device with high reliability.

The present invention relates to highly integrated semiconductor devices.

[Conventional technology]

Conventionally, regarding the connection between silicide and kt, ``Silicide 7 O Buyernis Eye Applications'' by Murarka (1983), pp. 156 to 161 (
” 5 ilicides for VLSI Appli
cations” ed by S, P, Mura
rka (1983) pp. 156-161), it has been thought that the connection between the two is stable up to about 500C and poses no problem in VLSI applications.

[Problem that the invention seeks to solve]

In the conventional technology, Al or Al alloy and silicide are in direct contact, and if the area of the connection is large, a sufficiently low resistance value can be obtained, but in a minute connection of about 1 μm or less, a reaction between the two The inventor's studies have revealed that the problem of high resistance occurs. The purpose of the present invention is to:

The purpose is to suppress the reaction between the silicide layer and the Al alloy layer and maintain an electrically stable connection.

[Means for solving problems]

The above object is achieved by avoiding direct contact between the Al alloy layer and the silicide layer and providing a reaction inhibiting layer between them.

[Effect]

High melting point metal nitride is a conductor and a very stable compound, so it hardly reacts with Al alloys and high melting point metal silicides during the heat treatment required in the semiconductor device manufacturing process, and maintains a stable structure. Therefore, it is extremely suitable as the reaction inhibiting layer.

〔Example〕

The present invention will be explained below with reference to Examples.

As shown in FIG. 1, a silicon oxide film 4 is formed on a Si substrate 5.
After forming WSiz, the WSiz was crushed by CVD and processed into a desired pattern 3 as a lower layer wiring through a normal photoetching process. Furthermore, after forming the insulating film 4', the opening 6 is
was formed. Next, as the upper layer wiring, 'I' iN chisel 2 and Al alloy (Al1%Si) layer 1 are laminated,
Processed into a predetermined pattern. Al layer 1. 'rrN layer 2 was formed by sputtering method 1 reactive sputtering method, but in order to withstand heat treatment of about 500C in the manufacturing process, as TiN layer 2, it is necessary to
A film thickness of about 1.0 m was required. In this example, TiN/
12 with two types of thickness: 50nm and 200nm.

A sample with a conventional structure without the TiN layer 2 was exploded. The resistance value was measured while additional heat treatment was applied to the pattern in which 100 connection parts shown in FIG. 1 were connected in series. Since the failure mode is an increase in contact resistance value, those with a resistance more than twice the initial normal resistance value (less than Ω/piece) are considered failures, and each approximately 10
The defect rate was calculated from the measurement of 0 samples. The results are shown in Table 1.

Table 1! As is clear from 11g19, it was confirmed that an increase in resistance value can be effectively prevented by providing a TiN layer.

〔Effect of the invention〕

According to the invention, even after the heat treatment required in the manufacturing process, Si
Since the resistance value at the connection between the element and the wiring does not increase and is kept stable, there is an advantage that high performance and highly reliable elements can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention. 1-Al alloy layer + 2・'riN layer, 3 = W S
i*/ilj. 2.1.1 1st concave / A18 Kinman 5S Ka-Pilgrimage,

Claims (1)

[Scope of Claims] 1. A semiconductor device having a connection portion between a high melting point metal silicide and an Al alloy, including a nitride layer of a high melting point metal at least between the high melting point metal silicide and the Al alloy in the connection portion. A semiconductor device characterized by: 2. The semiconductor device according to claim 1, wherein the high melting point metal silicide is tungsten silicide, molybdenum silicide, titanium silicide, or tantalum silicide, and the high melting point metal nitride is titanium nitride or tungsten nitride.