JPH07102367A - Production of sputtering target and semiconductor device - Google Patents

Abstract

PURPOSE:To prevent abnormal discharge which occurs during a sputtering process and to decrease production of foreign matter by forming a chamfered part on the outer edge of a sputtering target into a smooth curved surface. CONSTITUTION:A DC electric field or high frequency electrifc field is applied on a sputtering target 1 mounted on a backing plate 2 to perform sputtering and produced particles are deposited on a semiconductor substrate to form wiring. In the producing device of semiconductors by the sputtering process above described, the chamfered part D1, D2 on the outer edge of the sputtering target 1 is formed into a smooth curved surface. Thereby, concentration of stress due to thermal expansion in the sputtering target 1 is prevented, peeling of films formed by redeposition of particles produced in the sputtering process is avoided, and abnormal dischage is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique effective when applied to a sputtering process in a semiconductor device manufacturing method.

[0002]

2. Description of the Related Art In a sputtering process in a method of manufacturing a semiconductor device, heavy charged particles such as Ar cations are applied to a sputter target, and the particles ejected from the sputter target due to the impact thereof are attached to a facing sample. It is a thing.

As shown in FIG. 5, the conventional sputter target has a chamfered outer peripheral edge.

[0004]

[Problems to be Solved by the Invention] The sputtering process is
As described above, the cations of Ar or the like are irradiated to the sputter target, and the particles ejected from the sputter target by the impact are attached to the facing sample, but not all the particles ejected from the sputter target. However, it does not adhere to the sample, but some particles return to the sputter target and adhere again to form a film.

Further, heat is generated in the sputter target by irradiating Ar cations, and this heat causes stress in the sputter target due to thermal expansion.

This stress is concentrated especially in the angular portion of the chamfered portion of the sputter target. Therefore, if the film of particles described above is formed in the angular portion, the film peels off, flips up, and abnormal discharge occurs. Induce.

Due to this abnormal discharge, there is a problem in that particles (hereinafter referred to as "foreign matter") having a size different from that of sputtered particles are generated.

An object of the present invention is to provide a technique capable of preventing abnormal discharge that occurs during a sputtering process in manufacturing semiconductor devices and reducing the generation of foreign matter.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0010]

Of the inventions disclosed in the present application, a representative one will be briefly described below.
It is as follows.

In a sputtering target used in a sputtering process in manufacturing a semiconductor device, a chamfered portion on the outer peripheral portion of the sputtering target has a smooth curved surface.

Further, in a method of manufacturing a semiconductor device using a sputtering process for producing wiring of a circuit board or the like, the chamfered portion of the outer peripheral portion of the sputtering target used in the sputtering process is processed into a smooth curve, and the processed surface is processed. Use a sputtering process in which a DC electric field or a high frequency electric field is applied to the sputter target to perform sputtering.

[0013]

According to the above-mentioned means, the chamfered portion of the outer peripheral portion of the sputtering target used in the sputtering process is processed into a smooth curve, and a DC electric field or a high frequency electric field is applied to the processed sputtering target to perform sputtering. Therefore, even if a particle is ejected by the application of an electric field and reattaches to the chamfered portion of the outer peripheral portion of the sputter target and a film is formed, the chamfered portion of the outer peripheral portion of the sputter target is processed into a smooth curve. It is possible to prevent concentration of stress generated by thermal expansion of the.

Therefore, it is possible to prevent film peeling and reduce the generation of foreign matter that occur during the sputtering process.

The structure of the present invention will be described below together with embodiments.

In all the drawings for explaining the embodiments, parts having the same function are designated by the same reference numerals, and the repeated description thereof will be omitted.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an enlarged view of the outer peripheral portion of a sputtering target according to an embodiment of the present invention to show the characteristics of the shape of the outer peripheral portion. In FIG. 1, 1 is a sputter target and 2 is a backing plate. And sputter target 1
As the material of, for example, TiW is used, and it is preferable that each dimension thereof is set to a value such that D1 shown in FIG. D2 is 6.35 ± 0.1 mm, D3 is 324
± 0.2 mm. R1 is curved surface processing with a radius such that there is no angular portion and smoothly connecting, and R2 is curved surface processing with a radius of 2.0 mm.

Next, another embodiment of the present invention is shown in FIG.
FIG. 2 is an enlarged view of the outer peripheral portion for showing the characteristics of the outer peripheral portion shape of the sputter target of another embodiment of the present invention. Figure 2
The sputter target in Fig. 3 has a fan-shaped outer peripheral portion, and each dimension thereof is the same as that of the above-mentioned example.
Is 8 mm, D2 is 6.35 ± 0.1 mm,
D3 is 324 ± 0.2 mm.

FIG. 3 shows an example of a processing method for forming a curved surface into the shape of the sputter target of each embodiment. In FIG. 3, 1 indicates a sputter target and 3 indicates a grindstone. In the processing method shown in FIG. 3, the grindstone 3 is rotated to move the sputter target up and down to smooth the outer peripheral portion.

The processing method for processing the shape of the sputter target is not limited to this, and the sputter target material may be fitted into the mold to obtain a sputter target having a smooth outer peripheral portion.

Next, a method for forming a conductive film on a semiconductor wafer using the sputter target of the present invention will be briefly described.

First, TiW is used as a sputter target material for forming a conductive film, and the chamfered portion of the outer peripheral portion is curved to be the shape of the sputter target of this embodiment shown in FIG. 1 using a grindstone 3 shown in FIG. .

Then, the curved sputter target is placed on the cathode, and the semiconductor wafer to be sputtered is placed on the anode so as to face each other. Ar cations are injected between the cathode and the anode, and a DC voltage is applied to the cathode. Apply.

As a result, plasma is generated between the pair of electrodes, the sputtering target placed on the cathode is repelled by the ions in the plasma, and a conductive film is formed on the semiconductor wafer placed on the opposing anode.

Next, the number of foreign matters when the sputtering target of the present embodiment shown in FIG. 1 and the conventional sputtering target are mounted and sputtering is performed will be compared.

FIG. 4 is a diagram showing the number of foreign particles per power consumption when the sputtering target of this embodiment and the conventional sputtering target are mounted on a sputtering apparatus. In this test, a known sputtering device was used, and TiW was used as the sputtering target material.
In FIG. 4, the horizontal axis represents cumulative power consumption (KWH), and the vertical axis represents the number of foreign matters. Further, the broken line in FIG. 4 indicates the conventional sputter target, and the solid line indicates the sputter target of this embodiment.

In the conventional sputter target shown by the broken line in FIG. 4, a sudden increase in the number of foreign particles was observed,
There is evidence of abnormal discharge.

On the other hand, the sputter target of this embodiment has a small number of foreign matters in general and is stable, and no sudden increase in the number of foreign matters is observed until the cumulative power consumption exceeds 200 KWH.

That is, it is understood from FIG. 4 that the sputter target of the present embodiment can prevent abnormal discharge during the sputtering process and reduce the number of foreign matters.

As described above, by eliminating and smoothing the chamfered portion of the chamfered portion of the outer peripheral portion of the sputter target, there is no chamfered portion even if stress due to thermal expansion is generated by heat generated in the sputter target. There is no place where stress concentrates.

Therefore, even if particles that have jumped out of the sputter target during the sputter process in the manufacture of a semiconductor device adhere to the sputter target again to form a film, there is no place where stress concentrates, so the film peels off. It does not turn up, abnormal discharge can be prevented, and foreign matter can be reduced.

The inventions made by the present inventors are as follows.
Although the present invention has been specifically described based on the above-mentioned embodiments, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention.

[0033]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

By eliminating the angular portion of the chamfered portion on the outer peripheral portion of the sputter target and making it smooth,
Even if stress due to thermal expansion is generated by the heat generated in the sputter target, there is no angular portion, so there is no place where the stress concentrates. Even if a film is formed by adhering to the film, there is no place where stress is concentrated, so that the film does not peel off and flip up, abnormal discharge can be prevented, and the generation of foreign matter can be reduced.

[Brief description of drawings]

FIG. 1 is an enlarged view of an outer peripheral portion for explaining the shape of the outer peripheral portion of a sputter target according to an embodiment of the present invention.

FIG. 2 is an enlarged view of an outer peripheral portion for explaining the shape of the outer peripheral portion of a sputter target according to another embodiment of the present invention.

FIG. 3 is a diagram showing an example of a processing method for processing the outer peripheral portion of the sputter target into a curved surface.

FIG. 4 is a diagram showing the number of foreign particles per power consumption when the sputtering target is mounted on each of the sputtering target of the present embodiment and the conventional sputtering target.

FIG. 5 is an enlarged view of an outer peripheral portion for explaining the shape of the outer peripheral portion of a conventional sputter target.

[Explanation of symbols]

1 ... Sputter target, 2 ... Backing plate, 3
… Whetstone.

Claims (2)

[Claims] 1. A sputter target used in a sputter process in manufacturing a semiconductor device, wherein a chamfered portion of an outer peripheral portion of the sputter target has a smooth curved surface. 2. A method for manufacturing a semiconductor device using a sputtering process for producing wiring on a semiconductor substrate, wherein a chamfered portion of an outer peripheral portion of a sputtering target used in the sputtering process is processed into a smooth curve, and the processing is performed. A method of manufacturing a semiconductor device, characterized in that a sputtering process of applying a DC electric field or a high frequency electric field to a sputtering target to perform sputtering is used.