JPS5910225A - Formation of metal cilicide - Google Patents

Abstract

PURPOSE:To keep clean an IC and form a high purity metal silicide by heating a substrate having a single crystal silicon or polycrystalline silicon surface at a high temperature, depositing a metal thereon through the sputtering and forming a metal silicide film. CONSTITUTION:Silicon wafers 3 are placed on a sample stage with in a vacuum reservoir 1 and an Mo plate 5 is fitted as the target to the surface of opposing electrode 4. After the inside is exhausted to a vacuum condition through the exhausting port 6 and the silicon wafers 3 are heated with a heater 7 consisting of tantalum lead, the argon gas (Ar) is introduced from the gas introducing port 8, pressure is reduced and a DC voltage is applied with the opposing electrode 4 considered as the cathode. Thereby, the Ar ions collide with the Mo plate 4 and the activated Mo atoms are emitted therefrom and are deposited on the surface of silicon wafer 3 on the opposing sample stage 2. Since the surface of silicon wafer 3 is heated, the activated silicon atoms and Mo atoms react each other and a molybdenum silicide (MoSi2) can be formed.

Description

[Detailed description of the invention] Qλ) Technical field of invention The present invention relates to a novel method for forming silicide on gold.

(b) Conventional technology and problems Paper passing, molybdenum (+'VAO), tungsten (W)
Or silicide of high point metal such as platinum (1't) (
Silicon compound) is a high-performance semi-2 like LSI!・It became widely used as a conductor (i) wiring layer for IC circuits (IC).It is made of doped polycrystalline silicon (which has a resistivity about an order of magnitude brighter than that of doped polycrystalline silicon), which enables high-speed operation. This is because, like polycrystalline silicon, it is suitable for multilayer wiring structures.

By the way, sputtering (
When forming by a method (hereinafter referred to as sputtering), conventionally, a metal silicide material is used as a target, or a collus sputtering method is used in which sputtering is performed simultaneously from two targets of metal and silicon. Among them, the Nubatsuta device is simple and easy to operate when targeting metal silicide materials, but there are few high-purity metal silicides, which affects the quality of the IC itself.

Further, the collus sputtering method using two targets has the drawback that the sputtering operation is complicated and control is difficult.

An even more serious drawback is that when metal silicide is deposited on the top surface of an IC by sputtering in a continuous automatic processing process, the metal silicide attached to the jig in the equipment is fragile and easily peels off, so the metal silicide powder may not be deposited on the IC surface. The problem is that it adheres and contaminates the C element.

In order to improve the quality of ICs, automation of wafer processing steps including sputtering is desired, and from this point of view, contamination by metal silicide powder f is an extremely troublesome problem.

(0) Purpose of the Invention The present invention eliminates the above-mentioned problems, maintains the process C clean, and improves the level of the spuck method for forming high-purity metal silicide.

The purpose of the invention is to heat a substrate having a single crystal silicon or polycrystalline silicon surface to a high temperature, sputter and deposit a metal onto the substrate, and form a silicide of the metal. This is achieved by a method of forming

(e) Examples of the invention Hereinafter, one embodiment will be described in detail with reference to the drawings.

FIG. 1 shows an existing cross-sectional view of the spuck apparatus, in which a Nori-1 wafer 3 is placed on a stage 2 in a vacuum vessel 1, and a counter electrode 400 has a 5?!
-Getsu 1- Now that it is closed and installed, Makabe exhaust 1-
After applying vacuum suction from 16 and applying 700 OvC to the silicon wafer 3 using the Kuntal wire heater 7, argon (Ar) gas was introduced from gas introduction 1'Tl 3, and the degree of vacuum was reduced to 10- Torr, and applying a true current voltage of about gKV using the counter electrode 4 as a cathode. Then, Ar ions collide with the MO plate 5 and MO atoms are knocked out, and the silicon on the sample stage 2 facing the Deposited on 8 wafers. 700 wafers on 3 silicon wafers.
Because it is heated to
2) is created. If MO with a thickness of about 1000A is deposited, a Mo51g film with a thickness of about 200OA is formed, and its composition is determined by X-ray diffraction to be 1ylosii1.
It was confirmed that

By the way, it is necessary to make the third surface of the silicon wafer to which Mo is to be deposited an extremely clean surface in advance, and although it is not shown in FIG. 1, for example, as shown in FIG. 2, in the continuous processing step, Eight sides of the silicon wafer are etched by high frequency sputter etching in the etching chamber 10, and at the same time the load lock chamber 11 is opened in a vacuum with the diameter of the sputter chamber 1.
It is preferable to send the raw material into a tank 2, pre-process it without taking it out into the atmosphere, and then continuously sppack it. Although the evacuation [1] is not shown in FIG. 2, each chamber is evacuated to a vacuum state c or 13 indicates a gate pulp that connects each chamber.

The above example is MoSi. Although this is an example in which one film is formed, other metal silicide films can be formed in the same manner, and the type of metal, the heating temperature of the silicon substrate, and the composition of the silicide produced are shown in the following table.

According to the present invention, it is necessary that the substrate surface to be deposited by sputtering be made of single crystal silicon, polycrystalline silicon or amorphous silicon; if it is to be formed of other materials such as silicon oxide group, amorphous or polycrystalline silicon)
For example, in the continuous process shown in FIG.
A sputtering chamber for a non-+11+ (because a sputtered film is unlikely to become polycrystalline) or a polycrystalline silicon film may be placed in the 00 range.

If a metal silicide film is formed in this way, metal will adhere to parts of the jig other than the substrate 8, such as the exposed surface of the sample stage, in the sputtering device, and since it will not react with the jig, viscous metal will As it is, it adheres as it is,
It will not peel off. Therefore, the C-cut surface can be kept clean even during continuous processing.

(f) Effects of the Invention As is clear from the above explanation, the present invention can be applied to a continuous automatic processing process without contaminating IC elements, and can form highly pure metal silicide. Since the processing operation is easy, it is extremely useful for improving the quality of ICs.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of a sputtering apparatus to which the present invention is applied;
FIG. 2 is a continuous processing process diagram including pretreatment according to the present invention. In the figure, 8 is a silicon substrate, 2 is a sample stage, 4 is a counter electrode, 5 is a Mo target, 7 is a tantalum wire heater, and 10 is an etching chamber. Reference numeral 11 indicates a load lock chamber, and 12 indicates a sputtering chamber.

Claims (1)

[Claims] 1. A method for forming metal silicide, comprising the steps of depositing a metal onto the silicon substrate by sputtering while heating the silicon substrate to form a silicide film of the metal.