JPH097950A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE: To manufacture a semiconductor device of high quality with high yield by preventing a compound film from peeling off from a target itself or the inner wall of a reaction chamber in a reactive sputtering method. CONSTITUTION: After a TiN film is deposited on a semiconductor water 11, it is sputtered in an atmosphere made only of Ar in the state that a shield 13 is disposed between the wafer 11 and a Ti target 12. Thus, the TiN film 14 deposited on the target 12 is removed without depositing the film except the TiN film on the wafer 11, and the film 14 having deteriorated adhesive properties and deposited on the inner wall of a reaction chamber is covered with a Ti film having excellent adhesive properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device in which a compound film is deposited on a semiconductor wafer by a reactive sputtering method.

[0002]

2. Description of the Related Art In a semiconductor device, Ti is used as a reaction prevention barrier film between Si and Al wiring, an antireflection film in a lithography process when patterning Al wiring, and the like.
An N film is used. The TiN film is often formed by a reactive sputtering method. In this reactive sputtering method, N
_A Ti target is sputtered in an atmosphere of ₂ or N ₂ + Ar.

[0003]

By the way, the TiN film formed by the reactive sputtering method is not only deposited on the semiconductor wafer but also adhered to the Ti target itself, the inner wall of the reaction chamber and the like. However, since the TiN film is inferior in adhesion to the Ti film, the TiN film is easily separated from the Ti target, the inner wall of the reaction chamber, or the like. Therefore, conventionally, the peeled T
The iN film adheres to the semiconductor wafer as dust, which deteriorates the quality and yield of semiconductor devices.

In response to this, an attempt has been made to improve the adhesion of the TiN film by providing the shield covering the inner wall of the reaction chamber with irregularities. However, even by this attempt, the integrated film thickness of the TiN film up to the exfoliation was only increased to some extent, and this was not a fundamental solution.

[0005]

A method of manufacturing a semiconductor device according to claim 1, wherein a target is sputtered in an atmosphere containing a reactive gas to form a compound of a substance forming the target and the reactive gas. A method of manufacturing a semiconductor device in which a film is deposited on a semiconductor wafer, comprising the step of sputtering the target in an atmosphere containing only an inert gas, with a shield arranged between the semiconductor wafer and the target. It is characterized by doing.

A method of manufacturing a semiconductor device according to a second aspect is the method of manufacturing a semiconductor device according to the first aspect, characterized in that the sputtering in the state where the shield is arranged is performed for each semiconductor wafer of each sheet. There is.

A method for manufacturing a semiconductor device according to a third aspect is the method for manufacturing a semiconductor device according to the first aspect, wherein the sputtering in the state in which the shield is arranged is performed until the compound film attached to the target is removed. It is characterized by doing.

A method for manufacturing a semiconductor device according to a fourth aspect is the method for manufacturing a semiconductor device according to the first aspect, wherein the material forming the target is Ti and the reactive gas is N.
₂ , and the inert gas is Ar.

[0009]

Since the method of manufacturing a semiconductor device according to the present invention includes a step of sputtering the target in an atmosphere consisting of only an inert gas in a state where the shield is arranged between the semiconductor wafer and the target, Without depositing a film other than the desired compound film on the semiconductor wafer,
The compound film that adheres to the target itself is removed, and the compound film that adheres to the inner wall of the reaction chamber and has poor adhesion is made of only the substance that forms the target and has excellent adhesion. It can be covered with a membrane.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first and second embodiments of the present invention will be described below with reference to FIG.
Will be described with reference to. The first embodiment is a method of depositing a TiN film on a semiconductor wafer. In the first embodiment, as shown in FIG. 1, not only the semiconductor wafer 11 and the Ti target 12 can be accommodated, but also the semiconductor wafer 11 and the Ti target 12 are opposed to each other by the opening / closing operation. A reaction chamber in which the shield 13 can be arranged between the target 12 and the target 12 is used.

Then, as shown in FIG. 1A, first, a TiN film (not shown) is deposited on one semiconductor wafer 11 by the first stage sputtering under the following conditions.

Deposition conditions of TiN film Shield: Open gas species: N ₂ 100% Gas pressure: 8 mtorr DC power: 6 kW Heating temperature: 150 ° C. Film thickness: 100 nm

Next, as shown in FIG. 1 (b), the semiconductor wafer 11 and the Ti target 12 are left in the reaction chamber, and the second stage sputtering is continuously performed under the following conditions. In this second-stage sputtering, since the shield 13 is arranged between the semiconductor wafer 11 and the Ti target 12, no new film is deposited on the semiconductor wafer 11, and the film thickness of 300 nm is The film thickness that would be deposited if the semiconductor wafer 11 and the Ti target 12 are opposed to each other is shown.

Conditions for cleaning Ti target, etc. Shield: Closed gas species: Ar100% Gas pressure: 2 mtorr DC power: 6 kW Heating temperature: 150 ° C. Film thickness: 300 nm

After performing the above-described first-stage and second-stage sputtering on one semiconductor wafer 11, the semiconductor wafer 11 is taken out from the reaction chamber. Then, the next semiconductor wafer 11 is loaded into the reaction chamber, and the above-described first-stage and second-stage sputtering is performed again on the next semiconductor wafer 11. That is, the above-described first-stage and second-stage sputtering is performed for each semiconductor wafer 1
Do each one.

Also in the first embodiment as described above, in the first stage sputtering, as shown in FIG. 1A, a TiN film is deposited on the semiconductor wafer 11 as in the above-described conventional example. Not only the Ti target 12 itself and the inner wall (not shown) of the reaction chamber but also the TiN film 1 is formed on at least a part of the region.
4 adheres.

However, in the first embodiment, as shown in FIG. 1B, the T
The TiN film 14 attached to the i target 12 is removed and the surface becomes only Ti, and the TiN film 14 attached to the inner wall of the reaction chamber is covered with a Ti film (not shown). Then, the Ti film has better adhesion than the TiN film 14.

Therefore, it is possible to prevent the TiN film 14 attached to the Ti target 12 itself or the inner wall of the reaction chamber from being peeled off, and the peeled TiN film 14 from being attached to the semiconductor wafer 11 as dust. That is, in the second stage sputtering, the Ti target 12 is cleaned.

Since the TiN film 14 attached to the Ti target 12 itself has a non-uniform film thickness,
In order to completely peel off the N film 14, the semiconductor wafer 11
It is necessary to perform the second-stage sputtering by a film thickness that is at least twice the film thickness of the TiN film 14 deposited thereover, and in this first embodiment, the film thickness is tripled.

Next, a second embodiment in which a Ti film and a TiN film are continuously formed on a semiconductor wafer will be described. This second
Also in the example, the same reaction chamber as that used in the above-mentioned first example is used. Then, first, Ti is sputtered on one semiconductor wafer 11 by the first stage sputtering under the following conditions.
Deposit a film (not shown).

Conditions for Ti Film Deposition Shield: Open Gas Species: Ar 100% Gas Pressure: 2 mtorr DC Power: 6 kW Heating Temperature: 150 ° C. Film Thickness: 30 nm

Next, as shown in FIG. 1A, while the semiconductor wafer 11 and the Ti target 12 are left in the reaction chamber, the second stage sputtering under the following conditions is continuously performed to form a Ti film on the Ti film. Further, a TiN film (not shown) is deposited.

Deposition conditions of TiN film Shield: Open gas species: N ₂ 100% Gas pressure: 8 mtorr DC power: 6 kW Heating temperature: 150 ° C. Film thickness: 70 nm

Next, as shown in FIG. 1 (b), the semiconductor wafer 11 and the Ti target 12 are left in the reaction chamber, and the third stage sputtering under the following conditions is further continued.

Conditions for cleaning Ti target, etc. Shield: Closed gas species: Ar100% Gas pressure: 2 mtorr DC power: 6 kW Heating temperature: 150 ° C. Film thickness: 300 nm

After performing the above-described first to third steps of sputtering on one semiconductor wafer 11, the semiconductor wafer 11 is taken out of the reaction chamber. Then, the next semiconductor wafer 11 is loaded into the reaction chamber, and the above-described first to third steps of sputtering are performed again on the next semiconductor wafer 11. That is, the above first to third
The step-wise sputtering is performed for each semiconductor wafer 11.

In the second embodiment in which the Ti film and the TiN film are continuously formed, the same effect as that of the first embodiment can be obtained.

In the above first and second embodiments, T
Although the TiN film 14 was formed as the compound film using the i target 12 and N ₂ as the reactive gas, O ₂ or the like may be used as the reactive gas, and the WN film, the TiWN film, or the like may be formed as the compound film. You may.

[0029]

According to the method of manufacturing a semiconductor device of the present invention, the compound film attached to the target itself is removed,
In addition, the compound film that adheres to the inner wall of the reaction chamber or the like and has poor adhesion can be covered with a film that is made of only the substance forming the target and has excellent adhesion. For this reason,
It is possible to prevent the compound film from peeling off from the target itself or the inner wall of the reaction chamber, etc., and to prevent the peeled compound film from adhering to the semiconductor wafer as dust, and it is possible to manufacture high-quality semiconductor devices with high yield. .

[Brief description of drawings]

FIG. 1 is a schematic view showing a first embodiment and a part of a second embodiment of the present invention in process order.

[Explanation of symbols]

 11 semiconductor wafer 12 Ti target 13 shield 14 TiN film

Claims (4)

[Claims] 1. A method of manufacturing a semiconductor device, comprising sputtering a target in an atmosphere containing a reactive gas to deposit a compound film of a substance forming the target and the reactive gas on a semiconductor wafer, A method of manufacturing a semiconductor device, comprising a step of sputtering the target in an atmosphere containing only an inert gas in a state where a shield is arranged between the semiconductor wafer and the target. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the sputtering in the state where the shield is arranged is performed for each of the semiconductor wafers. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the sputtering is performed in a state in which the shield is arranged until the compound film attached to the target is removed. 4. The material forming the target is T
i, the reactive gas is N ₂ , and the inert gas is Ar.
The manufacturing method of the semiconductor device described in the above.