JP3442831B2 - Method for manufacturing semiconductor device - Google Patents

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 for 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 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]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

The present invention is directed to a first plane and the first plane.
And a sputter material having a second flat surface on the opposite side, and the spa
From the backing plate joined to the first plane of the cutter
Prepare a sputter target that will be opposite to the second plane
Then, the semiconductor wafer is installed, and the semiconductor wafer
Including the step of attaching particles of the sputter target to the surface
A method for manufacturing a semiconductor device, comprising:
On the outer peripheral side surface between the first plane and the second plane.
At the boundary between the first plane and the side surface of the outer peripheral portion,
And a boundary portion between the second flat surface and the outer peripheral side surface, respectively.
It is characterized by smooth curved surface processing.

That is, the present invention is directed to the first main surface and the second main surface.
A sputtered material having a surface and a first main surface of the sputtered material
Sputter target consisting of joined backing plate
Of the semiconductor wafer by facing the second main surface.
A wafer is installed and a sputterer is attached to the main surface of the semiconductor wafer.
Manufacturing of a semiconductor device including a step of attaching particles of a get
A method, comprising:
Part of one main surface is exposed, and the first main surface and the second main surface
In the outer peripheral side surface between the first main surface and the
Being in contact with the second main surface and being curved
And are characterized by. The present invention also provides a first main surface.
And a sputter material having a second main surface, and
Spa consisting of a backing plate joined to the first main surface
The process of preparing the target
Facing the second main surface of the sputter target.
Install the semiconductor wafer and place it on the semiconductor wafer.
A method of manufacturing a semiconductor device, including the step of forming a thin film.
Therefore, the sputter target is
A part of the first main surface in the outer peripheral portion is exposed,
In the outer peripheral side surface between the first main surface and the second main surface,
A curved surface in contact with the first main surface and the second main surface
In the process of forming the thin film,
Apply DC electric field or high frequency electric field to sputter target
It is characterized by carrying out sputtering.
It

[0013]

According to the above-mentioned means, the outer circumference of the sputtered material is
The part has a smooth curve, that is, in FIG.
Bottom surface (first main surface) joined to the backing plate
In contact with the curved line such as R2, and in contact with the upper surface (second main surface) R
It forms a curve like 1. Therefore, the spatterer
Concentration of stress in the film due to particles reattached to the outer periphery of the get
This prevents peeling and abnormal discharge from occurring.
Wear. Further, according to the above-mentioned means, the sputtering process
The chamfered portion on the outer periphery of the sputter target used in
Processed into a smooth curve, and the processed sputter target
DC electric field or high frequency electric field is applied to the
Particles are ejected by applying an electric field.
Re-attach to the chamfered portion of the outer periphery of the target to form a film.
Even if formed, since 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 sputter target.

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
For example, TiW is used as the material of the above, and the respective dimensions are as follows . D1 shown in FIG. 1 is preferably set to a value that does not exceed 9 mm from the outer circumference, and is set to 8 mm here. 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, FIG. 2 shows a reference example related to the present invention . FIG. 2 is a reference example related to the present invention and is an enlarged view of the outer peripheral portion for showing the characteristics of the outer peripheral portion of the sputter target. The sputter target shown in FIG. 2 has a fan-shaped outer peripheral portion, and the respective dimensions thereof are D1 = 8 mm and D2 = 6.35 ±, similarly to the above-mentioned example.
0.1 mm and 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, 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 sputter 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 specific description has been given based on the above-described embodiments, the present invention is not limited to the above-described 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 which is a reference example 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.

Continuation of the front page (56) Reference JP-A-63-153266 (JP, A) JP-A-6-306596 (JP, A) JP-A-6-306597 (JP, A) JP-A-6-248444 (JP , A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) C23C 14/00-14/58 H01L 21/203 H01L 21/31

Claims (2)

(57) [Claims] 1. A first plane and opposite to the first plane
A sputtering target having a second flat surface on the side and a backing plate bonded to the first flat surface of the sputter material, and the semiconductor wafer is set to face the second flat surface . a method of manufacturing a semiconductor device including a step of depositing particles of the sputter target surface, the sputter target is at the outer periphery side between the first and second planes, the outer periphery and the first plane Department
A boundary portion with a side surface , and the second flat surface and the outer peripheral side surface
A method for manufacturing a semiconductor device, characterized in that each of the boundary portions of the is subjected to smooth curved surface processing. 2. A first plane and opposite to the first plane
A sputter material having a second flat surface on the side and a backing plate bonded to the first flat surface of the sputter material; and a step of facing the second flat surface of the sputter target in a sputtering device. A semiconductor wafer, and a step of forming a thin film on the semiconductor wafer, wherein the sputtering target is provided on a side surface of an outer peripheral portion between the first plane and the second plane . , The first plane and the outer peripheral portion
A boundary portion with a side surface , and the second flat surface and the outer peripheral side surface
Smooth boundary surface processing is applied to each boundary part of
In the step of forming the thin film, a sputtering method is performed by applying a DC electric field or a high frequency electric field to the sputtering target.