JPS6376321A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To carry out an Al sputtering process and an Al deposition process by keeping the ratio of partial pressure of an undesirable gas component, such as nitrogen or the like, at an extremely low level in such a way that a metal material such as Ti, Ta, Zr, Nb, Mo, W, La or the like is sputter-etched. CONSTITUTION:While a wafer 3 is put on the side of a Ta target 6, a vacuum chamber 2 is evacuated by means of a cryopump 4 until, e.g., 4X10<-7> Torr can be reached. As soon as a prescribed degree of vacuum has been reached, an Ar gas of high purity is introduced into the vacuum chamber 2 through an Ar supply pipe 5, and the Ta target is sputter-etched by glow discharge. During this process Ta is not deposited because the wafer 3 is put at the position as shown in the figure. If, after completion of a Ta sputtering process, the Ar supply pipe 5 is closed, the degree of vacuum inside the vacuum chamber 2 reaches the level of 1X10<-7> within a few minutes. This occurs because the partial pressure of these gases is lowered due to the reaction of Ta with nitrogen and oxygen. Through this constitution, it is possible to reduce the content of undesirable impure chemical elements such as nitrogen or the like to be contained in an Al (alloy) film, and to improve the life of electromigration and the resistance to a hillock.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of manufacturing a semiconductor device in which an At or A4 alloy thin film for electrodes and wiring is formed on a wafer.

[Conventional technology]

Conventionally, this method of manufacturing semiconductor devices is based on wafers.
After transporting the entire X into the chamber and evacuating the vacuum chamber with a cryopump or oil diffusion pump, At and At agglomerates were attached to the quafer by sputtering or vacuum evaporation.

[The problem that the invention attempts to solve]

In the conventional semiconductor device manufacturing method described above, when an oil diffusion pump is used to evacuate the Makabe chamber, the degree of vacuum is 10.
- Even if the temperature reaches the Torr range, the partial pressure ratios of nitrogen, hydrogen, and water before exhaust are almost maintained. Even when using a cryopump, the partial pressure ratio of fractions with high vapor pressure such as hydrogen will be higher after co-airing compared to before evacuation, and the partial pressure ratio of components with relatively low vapor pressure such as water will be lower. Nitrogen and oxygen exist at fairly high partial pressure ratios.

Using a load-lock type sputtering device, the vacuum chamber is evacuated to 4.0XIO Torr and then sputtered.As a result of Auger electron spectroscopy, ~5 at% nitrogen is found in the At film or At/Cu alloy film. A friend who exists throughout the entire country.

The remaining impurity gases are dissolved in nitrogen, oxygen, hydrogen, moisture, etc. without affecting the electro-migration lightning life or hillock resistance of the At film or At/Cu alloy film, and the size of the shadow is determined in this order. That is, it is the components of the atmosphere that do not have a large influence on the film quality, and the conventional semiconductor device manufacturing method has the disadvantage that these impurity components cannot be sufficiently removed.

In contrast to the conventional semiconductor device manufacturing method described above, the present invention has an original content in that At sputtering or At vapor deposition is performed while keeping the partial pressure ratio of undesirable gas components such as nitrogen in a vacuum chamber extremely low.

[Means for solving problems]

The method for manufacturing a semiconductor device of the present invention includes an evacuation step of carrying a wafer into a vacuum chamber and evacuating the inside of the vacuum chamber to a higher vacuum than IX I O-' Torr using a cryopump; High-purity Ar gas is introduced into Ti and Ta.

a sputter etching step of sputter etching a metal that actively reacts with atmospheric component gas such as zr, Nb1M00W, La or an alloy material containing at least one of these metals so as not to adhere to the wafer; and A by using gas sputtering method or vacuum evaporation method
t"! or A/, a deposition step of depositing the alloy onto the wafer.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

1) g is a detailed explanatory diagram for explaining the first embodiment of the present invention, and shows a wafer 3 being carried into a vacuum chamber 2 from a load lock chamber l of a sputtering apparatus.

The wafer 3 is attached to a Ta target 6 as shown in FIG.
At a side position, the inside of the vacuum chamber 2 is evacuated by the cryopump 4 until the pressure reaches, for example, 4×10-7 Torr.

When a predetermined degree of vacuum is reached, high-purity Ar gas is introduced into the vacuum chamber 2 from the Ar pipe 5, and the Ta target 6 is subjected to glow discharge sputter etching. At this time, since the wafer 3 is in the position shown in FIG. 1, Ta is not attached. After the Ta sputtering is completed, the Ar pipe 5 is closed and the vacuum level of the vacuum chamber 2F3 reaches lXl0-'T within a few minutes.
Reach the orr platform. This is due to the reaction between Ta, nitrogen, and oxygen, and the partial pressure of these gases has decreased.
The wafer 3 is moved in front of the At target 7 or the At/Cu alloy target 8, and high-purity Ar gas x2 is introduced to coat the wafer 3 with a predetermined thickness of At or Al using sputtering.
Deposit a t/Cu alloy thin film.

As explained above, vacuum chamber 2't 4.0XIO
” After creating a high vacuum to -7 Torr, Ta target 6
After sputter etching for 3 minutes, a 1 μm thick At film was deposited by sputtering on the St substrate wafer 3 on which 8i (J2 was formed) and the sample was heated to 460°C for 30 minutes. The occurrence of hillocks with a height of 200 mm could be suppressed to a linear density of ~15 pieces/c!IL.

In addition, the hillock linear density of the sample prepared using the conventional method is ~2
8 pieces/crrL.

FIG. 2 is an explanatory diagram for explaining a second embodiment of the present invention.

The first embodiment described above shows an example in which the present invention is applied to a sputtering apparatus that is currently in general use.A Ta target, which is intended for sputtering to adsorb nitrogen, etc., is used to form a thin film uniformly on a wafer. Unlike the target to which it is attached, it does not require a large area.

In FIG. 2, a relatively small Ta target 6 is used for adsorbing impurity gases such as nitrogen, and Ta sputtering without adhering to the wafer 3 is performed immediately before sputtering to adhere At (alloy) to the wafer 3. With At
(Alloy) This is also done at the same time during sputtering.

In addition, in FIG. 1 and FIG. 2, the canned electrodes of each target, the oil rotary pump, the piping system of the load lock chamber, the wafer transport mechanism, etc., which are not directly related to the explanation of the present invention, are omitted.

〔Effect of the invention〕

As explained above, the present invention provides s T i *'ra*
By sputter etching metal materials such as z+rINb, Mo, W, and La in a vacuum chamber and depositing At or A4 alloy on the wafer with a low partial pressure ratio of impurity gas such as nitrogen, The content of undesirable impurity elements such as nitrogen can be reduced, and the electro-migration resistance and corrosion resistance can be improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram for explaining a first embodiment of the present invention, and FIG. 2 is an explanatory diagram for explaining a second embodiment of the present invention. 1...Load lock chamber, 2...Vacuum chamber, 3...Wafer, 4...Cryopump, 5...Ar piping, 6...
Ta target, 7...A/, target, 8
...At/Cu alloy target. Agent Patent Attorney Susumu Uchihara

Claims (2)

[Claims] (1) Transport the wafer into a vacuum chamber and use a cryopump to pump the inside of the vacuum chamber to 1 x 10^-^6 Torr.
an evacuation process to achieve a high vacuum even by r, and introducing high-purity Ar gas into the vacuum chamber to remove Ti,
a sputter etching step of sputter etching a metal that actively reacts with atmospheric component gases such as Ta, Zr, Nb, Mo, W, La, or an alloy material containing at least one of these metals so as not to adhere to the wafer; . A method for manufacturing a semiconductor device, comprising the steps of: adhering Al or an Al alloy to the wafer by a sputtering method using the high-purity Ar gas or a vacuum evaporation method. (2) The method of manufacturing a semiconductor device according to claim 1, wherein the sputter etching step is performed simultaneously during the adhesion step.