JPH0433332A - Manufacture of semiconductor device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for forming wiring.

(Prior Art) In semiconductor devices, wiring is formed using M or AI-Si alloy, but when this M or N-Si alloy is formed in direct contact with a semiconductor substrate in a contact hole, it is difficult to form an ohmic contact. During the heat treatment to obtain N-Si, supersaturated Si in the N-Si alloy, or Si sucked up from the substrate into M, grows solid-phase epitaxially as a PI layer on the substrate surface (contact part) at the bottom of the contact hole. There was a problem that contact resistance increased.

In order to prevent this increase in contact resistance, as shown in FIG. 2, a high melting point metal silicide film (
For example, a WSiX film)2 is formed.

However, in this method, during the heat treatment to establish ohmic contact, the high melting point metal silicide film 2
The Si inside melts into the wiring metal, and when the temperature drops, the Si
This causes the problem that the Si nodules 3 are scattered in the wiring metal l, and since the Si nodules 3 have a high resistance,
There was a problem in that it increased the resistance of the wiring, leading to deterioration in reliability. In particular, if this Si inodine occurs in the first wiring layer of a multilayer wiring, and moreover at the connection part with the second wiring layer, it not only increases the resistance of the connection part, but also causes poor interlayer connection of the wiring. There was a problem.

Therefore, the applicant, jointly with an affiliated company,
We proposed a method for preventing the generation of Si nodules, as we filed a patent application as Japanese Patent Application No. 1-206880 on May 11th. In this method, as shown in FIG. 3(a), the semiconductor substrate bl
After forming an intermediate insulating film 12 thereon and opening a contact hole 13, a high melting point metal silicide M14 is deposited, and immediately thereafter heat treatment is performed at a high temperature of 650''C or higher to form a high melting point metal silicide film 14. After crystallizing or promoting crystallization, a wiring metal 15 is deposited thereon as shown in FIG. 3(b), buttered, and heat treated at a low temperature of about 400°C to establish ohmic contact. This is the way to do it.

In this method, the high melting point metal silicide 1114 is crystallized in advance or the crystallization is accelerated.
This technique attempts to prevent Si nodules from being generated within the wiring metal 15 during subsequent heat treatment to obtain ohmic contact.

(Problems to be Solved by the Invention) However, even with the above-mentioned proposed technology, the prevention of Si nodules from occurring is not completely possible, and Si nodules are sometimes observed to occur, resulting in an increase in wiring resistance.

Furthermore, when the high melting point metal silicide film is crystallized or its crystallization is promoted, a problem arises in that ohmic contact cannot be obtained.

This invention was made in view of the above points, and it is possible to reliably prevent the generation of Si nodules in a wiring formation method in which a high melting point metal silicide film is formed as a barrier metal under the wiring metal, and also to It is an object of the present invention to provide a method for manufacturing a semiconductor device that can obtain good ohmic contact.

(Means for Solving the Problems) In the present invention, a high melting point metal silicide film, a wiring metal, and a metal capable of forming a silicide are sequentially formed as wiring on a semiconductor substrate, and then an ohmin contact film is formed between the semiconductor substrate and the substrate. Heat treatment is performed to obtain contact.

(Function) In the above method, when heat treatment is performed to obtain ohmic contact, Si is removed from the high melting point metal silicide film.
is dissolved into the wiring metal, but this Si is consumed by reacting with the metal that can form silicide on the wiring metal and forming a silicide layer, so it appears as 31 nodules in the wiring metal. disappears.

Furthermore, according to the above method, there is no need to crystallize or promote crystallization of the high melting point metal silicide film, and since these are not performed, good ohmic contact can be achieved by heat treatment to obtain ohmic contact. can get.

(Example) An embodiment of the present invention will be described below with reference to FIG.

In one embodiment, as shown in FIG. 1(a), first, an intermediate insulating film 22 is formed on a silicon substrate 21 on which element formation has been completed, and a contact hole 23 is formed in a part of the intermediate insulating film 22. A high melting point metal silicide film, for example, WSixM24, is formed by sputtering or the like on the entire surface of the intermediate insulating film 22 so as to be in contact with the silicon base 121 surface at the hole 23.
Form to a thickness of 100 mm and 0 thickness. Subsequently, a /u-1,0% Si alloy film 25 is similarly formed thereon as a wiring metal to a thickness of 600r+s+ by sputtering. Furthermore, on top of that, a W film 2 is formed as a metal that can form silicide.
6 is formed to a thickness of about 300 nm by sputtering.

Next, regular lithography (photolithography and etching)
Depending on the process, the W film 26. By patterning the AZ-1.0% Si alloy film 25 and the WSiX film 24 as shown in FIG. 1 (bl), a three-layer interconnection structure is formed.

Thereafter, a heat treatment to obtain ohmic contact with the substrate 21 is performed at a low temperature of about 400° C., as shown in FIG. 1 fC). At this time, from the W S i +l film 24 as shown in FIG.
As shown by the arrow in C1, Si melts into the AZ-1.0% Si alloy film 25, but this St
Since it is consumed by reacting with the W film 26 on the Si alloy llI25 to form a silicide layer, ・N-1.0%S
Si nodules no longer appear in the i-alloy film 25. Furthermore, since the W S i

Note that in the above embodiment, Af-Si is used as the wiring metal.
Although an alloy was used, 100% M may also be used. Further, although tungsten (W) was used as a metal capable of forming silicide, molybdenum (-〇), cobalt (Go), etc. can also be used. Furthermore, the metal capable of forming silicide can be formed by patterning the lower two layers of wiring metal and high-melting point metal silicide film into a wiring pattern, and then forming the metal so as to cover the entire wiring metal pattern by selective CVD or the like. .

(Effects of the Invention) As described above in detail, according to the manufacturing method of the present invention, Si dissolved from the high melting point metal silicide film into the wiring metal during heat treatment for obtaining ohmic contact is removed from the overlying film. Since the Si nodules are consumed by reacting with the metal to form a silicide layer, generation of Si nodules in the wiring metal can be reliably prevented. Therefore, it is possible to obtain wiring with low resistance and high reliability without interlayer connection defects in multilayer wiring.

In addition, the high melting point metal silicide film used as a barrier metal does not need to be crystallized or to promote crystallization.
Since no heat treatment is performed, good ohmic contact can be obtained by heat treatment.

In addition, if a metal that can form silicide is formed on the wiring metal, it is possible to lower the reflectance and improve the pattern accuracy when patterning the wiring pattern using the lithography process. can.

Furthermore, if a metal capable of forming silicide is formed on the wiring metal, it is possible to prevent the occurrence of hillocks in the aluminum alloy due to heating of the wiring, and it is possible to obtain higher quality wiring.

[Brief explanation of the drawing]

FIG. 1 is a process cross-sectional view showing an embodiment of the semiconductor device manufacturing method of the present invention, FIG. 2 is a cross-sectional view showing a conventional wiring forming method, and FIG. FIG. 21... Silicon substrate, 24... W S i X film, 25... AZ-1,0%51 alloy film, 26... W
film. Procedural amendment written on 17th November 2016

Claims (1)

[Claims] A semiconductor characterized in that a high melting point metal silicide film, a wiring metal, and a metal capable of forming silicide are sequentially formed as wiring on a semiconductor substrate, and then heat treatment is performed to obtain ohmic contact with the substrate. Method of manufacturing the device.