JPH0480352A - Sputtering system - Google Patents

Abstract

PURPOSE:To prevent the electrostatic breakage of a deposition preventive plate and to prevent the contamination with dust by previously forming an insulating film in a specified thickness on the plate arranged along the inner wall as the counter electrode to an electrode to be supplied with a high-frequency wave in a treating chamber. CONSTITUTION:An electrode 8 to be supplied with a high-frequency wave and a deposition preventive plate 10 arranged along the inner wall 9 (chamber wall) of the etching chamber to be used as the counter electrode to the electrode 8 are provided in the etching chamber 2 to constitute a sputtering system A, and an insulating film 21 is previously formed in a specified thickness on the plate 10. Consequently, the capacity of a capacitor formed by the plate 10, insulting film 21 and charge accumulating part (a) is lowered, and the amt. of the plasma charge to be accumulated is decreased. Accordingly, the electrostatic breakage (unnecessary discharge) due to the accumulation of the plasma charge in the plate 10 in sputtering is prevented, and the contamination with dust resulting from the unnecessary discharge is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sputtering apparatus that performs plasma etching by the sputtering effect of ions using high frequency discharge and inert gas in a processing chamber.

[Summary of the invention]

The present invention provides a sputtering apparatus comprising an electrode to which a high frequency is supplied in a processing chamber and an anti-adhesion plate disposed along the wall of the processing chamber, which serves as a counter electrode. By forming and configuring it to a predetermined thickness, it is possible to prevent electrostatic damage (unnecessary discharge) due to the accumulation of plasma charge on the adhesion prevention plate during sputtering processing, and to suppress dust contamination caused by the unnecessary discharge. It is something.

[Conventional technology]

Generally, in multi-layer wiring using M in semiconductor devices, as shown in Fig. 3, in order to establish an electrical connection between the lower layer M wiring (31) and the upper layer M wiring (indicated by a chain double-dashed line) (32), , an interlayer insulating film (Sin2) on the lower layer M wiring (31)
After opening a contact hole (34) in (33), an M film (32) for upper layer wiring is deposited.
Immediately before depositing the M film (32), a method is used in which the natural oxide film (M203 = 50) (35) on the underlying M wiring (31) is etched away using high-frequency plasma such as argon gas. ing. This technique is commonly referred to as reverse sputter etching or radio frequency etch cleaning. In FIG. 3, (36) is a silicon substrate, and (37) is a 5in2 film.

This high frequency etch cleaning is performed using a sputtering device (B) as shown in FIG.

As shown in the figure, this sputtering apparatus (B) has an electrode (44) in a processing chamber (41) connected to a high frequency power source (42) and on which a wafer (43) is placed. The inner wall of the processing chamber (chamber wall) (45) itself is configured to serve as a counter electrode to the electrode (44). Note that (46) is an argon gas inlet, and (47) is an exhaust port.

When performing high frequency etch cleaning, use the electrode (44
), plasma is generated in the processing chamber (41), and in this plasma generation region (P), argon gas is converted into argon ions (Ar'').
and dissociate into plasma charges (electrons), among which argon ions (Ar'') strike the wafer (43) with the acceleration action of the electric field, and the 5in2 film (33) formed on the wafer (43) A part of the surface of and the M layer (31〉
This is to remove the upper M2O3 film (35) by impact. The 5102 and M2O3 removed during the above etching adhere to the chamber wall (45), which is the counter electrode, but in order to facilitate cleaning (maintenance) of the chamber wall (45) later, an adhesion prevention plate (45) is prepared in advance. 48) are arranged along the chamber wall (45) and the electrode (44), and the adhesion prevention plate (48) is placed along the chamber wall (45) and the electrode (44).
It is common to exchange.

Note that the adhesion prevention plate (48) is held at the same potential as the chamber wall (45).

[Problem to be solved by the invention]

As described above, by disposing the adhesion prevention plate (48), the SiO3 removed by the impact of argon ions during the high frequency etch cleaning is removed as shown in FIG. 5A.
and Al2O3 adhere to the anti-adhesion plate (48), and 5.
An insulating film (49) made of in2 or M2C will be formed, but while this film (49) is thin, plasma charges (electrons) will pass through the pinhole (50) formed in the film (49). The adhesion prevention plate (48) side, that is, the chamber wall (4
5) Run to the side. However, as shown in FIG. 5B, when the insulating film (49) is deposited to the extent of several hundred layers, there is no place for the plasma charge to escape, and a capacitor structure is formed, where a large amount of plasma charge is accumulated, and eventually , insulating film (
49) causes electrostatic damage in the thin part and induces discharge (unnecessary discharge). At this time, a large amount of heat is generated, and the insulating film (49) melted by this heat becomes droplets and flies off, causing the insulating film (49) to adhere to the wafer (43) and cause dust contamination. This inconvenience arises. As shown in Figure 5C, when the insulating film (49) attached to the anti-adhesion plate (48) becomes even thicker and the number of people exceeds about 1,000, the capacitor capacity decreases and the plasma charge accumulates. The amount also decreases, and the above-mentioned unnecessary discharge is no longer induced.

However, it takes a considerable amount of time to reach the shape shown in Figure 5C, and most of the time, as shown in Figure 5B,
The current situation is that unnecessary discharge causes dust contamination, leading to a decrease in yield.

Therefore, before taking the form shown in Figure 5B, we prepared the anti-adhesion plate (48
), but this method has the disadvantage of complicating maintenance and reducing work efficiency. It is also conceivable to use a glass plate or a ceramic plate as the adhesion prevention plate (48), but there are problems in that it is easily broken and expensive, and it is not suitable for covering a large area.

The present invention has been made in view of the above points, and its purpose is to prevent electrostatic damage (unnecessary discharge) due to the accumulation of plasma charge on the deposition prevention plate during sputtering processing, and to eliminate the need for such damage. An object of the present invention is to provide a sputtering apparatus that can suppress dust contamination caused by discharge.

[Means to solve the problem]

The present invention provides an electrode (8) to which a high frequency is supplied in a processing chamber (2), and an adhesion prevention plate (10) disposed along a processing chamber wall (9) serving as an opposing electrode. In the sputtering apparatus (A) comprising the above-mentioned deposition prevention plate (10
) is formed by forming an insulating film (21) to a predetermined thickness in advance.

[Effect]

According to the configuration of the present invention described above, since the insulating film (21) of a predetermined thickness is formed on the adhesion prevention plate (10) in advance,
Adhesion prevention plate (10), insulating film (21), and charge accumulation part (a)
The capacitance of the capacitor made up of the plasma decreases, and the amount of plasma charge accumulated decreases. Therefore, electrostatic discharge damage (unnecessary discharge) due to accumulation of plasma charges on the deposition prevention plate (10) during sputtering can be prevented in advance, and dust contamination due to unnecessary discharge can be suppressed.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to FIGS. 1 and 2.

FIG. 1 is a configuration diagram showing a sputtering apparatus (A) according to this embodiment.

This sputtering apparatus (^) consists of a loading chamber (1), an etching processing chamber (2), and a sputtering processing chamber (3), and the loading chamber (1) accommodates unprocessed urethane (4). It has a cassette (5) and a cassette (6) that accommodates processed wafers (4). The etching processing chamber (2) is connected to a high frequency power source (300W) (7) inside, and has an electrode (8) on which the sea urchin (4) is placed on the top surface, and an inner wall of the processing chamber that serves as the opposite electrode. It has an adhesion prevention plate (10) arranged along the chamber wall (9). This anti-adhesion plate (10
) are preferably also arranged around the electrode (8). still,
(11) is an inert gas inlet, and (12) is an exhaust port. The sputtering chamber (3) is formed by vertically disposing a target layer (13).

When using this sputtering apparatus (A), first, an unprocessed wafer (4) is placed in a cassette (5) in the load chamber (1), and the wafer is evacuated through the exhaust port (14). . Next, open the vacuum valve (15) and
4) is transported one by one to the etching processing chamber (2), and
(4) is placed on the electrode (8). In this etching chamber (2), for example, a process (high frequency etch cleaning) is performed to remove the M2O3 film on the lower layer M wiring shown in FIG. At this time, for example, argon gas is introduced from the inert gas inlet (11) into the processing chamber (2).
) to create an argon gas atmosphere of about 4 mTorr.

Then, a high frequency is supplied to the electrode (8) from a high frequency power source (7) to generate plasma in the processing chamber (2). Argon gas is dissociated into argon ions (Ar") and plasma charges (electrons) in the plasma generation region (indicated by a broken line) (P), and among these, argon ions (Ar") and plasma charges (electrons) are generated.
”) is accelerated by an electric field and hits the wet film (4), for example, a part of the surface of the 5102 film shown in Fig. 3 and the M2O film are removed by impact. It is held at the same potential as the wall (9) and also functions as a counter electrode for the electrode (8).This etching process also has the ability to etch about 100 degrees or more per minute.

Thereafter, the vacuum valve (16) is opened and the wafer (4) is transported to the sputtering chamber (3).
) is placed in the vertical direction so that its treated surface faces (13). Then, M and T of the target material
A metal such as i is sputter-deposited to form, for example, an upper wiring layer shown by a two-dot chain line in FIG.

In this case, since the wafer (4) is installed vertically, dust adhesion is reduced.

The treated piece after the sputtering process (4) is
It is returned to the load chamber (1) again and housed in the cassette (6). Incidentally, if there is another treatment after this sputtering treatment, the Ueno\(4) is transported to a corresponding treatment chamber (not shown).

In this example, as shown in FIG. 2, an insulating film (
21) is formed to a predetermined thickness. In this example, an M plate whose surface is alumite (anodized) treated is used as the anti-adhesion plate (10). The thickness of this M plate (10) is approximately 1 mm.
The thickness of the M2O film (21) obtained by alumite treatment may be approximately 1000 or more. As a method for forming the M2O film (21) on the surface of the M plate (10), in addition to the above methods, for example, a sputtering method, a CVD method, etc. can be used. Moreover, it is preferable that the adhesion prevention plate (10) be arranged so as to cover as much of the surface as possible other than the wafer (4).

As mentioned above, according to this example, the anti-adhesion plate (10) is preliminarily coated with 10
Since the insulating film (21) having a thickness of about 0.00 mm or more is formed, during the etching process, the adhesion prevention plate (10), the insulating film (21), the main surface of the insulating film (21),
That is, the capacitance of the capacitor constituted by the charge storage portion (a) decreases, and the amount of plasma charge accumulated in the charge storage portion (a) decreases. As a result, electrostatic discharge damage (unnecessary discharge) due to the accumulation of plasma charges on the deposition prevention plate (10) during etching processing is prevented, and dust contamination caused by unnecessary discharge can be suppressed, and the formation of dust on the wafer (4) Accordingly, it is possible to achieve a high yield of semiconductor devices.

Furthermore, since the M plate is used as the adhesion prevention plate (10), it has sufficient strength and is advantageous in terms of cost compared to a glass plate.

In the above embodiment, M 2 D 3 is used as the insulating film (21).
Although a film was used, a SiO□ film or the like may also be used. In addition, a stainless steel plate was used as an anti-adhesion plate (<10), and by coating the stainless steel plate with silanol (Si20) dissolved in an organic solvent and baking, the surface of the stainless steel plate was coated with SlO.
□ A film may be formed.

Alternatively, an M2O film with a thickness of approximately 0.1 mm may be deposited on one side (the side facing the processing chamber (2)) of the adhesion prevention plate (10) made of stainless steel or the like by plasma spraying. good. In this case, it is effective for forming an insulating film (21) on a large-area adhesion prevention plate (10).

〔Effect of the invention〕

According to the sputtering apparatus according to the present invention, electrostatic discharge damage (
This makes it possible to prevent dust contamination caused by unnecessary discharges and improve the yield of semiconductor elements on wafers.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a sputtering apparatus according to this embodiment, FIG.
4 is a configuration diagram showing a sputtering apparatus according to a conventional example, and FIG. 5 is an explanatory diagram showing the function of a deposition prevention plate according to a conventional example. (A) is sputtering equipment, (1) is load chamber, (2)
is an etching processing chamber, (3) is a sputtering processing chamber, and (4) is a sputtering processing chamber.
is the wafer, (5) and (6) are the cassettes, (7) is the high frequency power supply, (8) is the electrode, (9) is the chamber wall, and (10) is the wafer.
) is the anti-adhesion plate, (P) is the plasma generation area, (21)
is an insulating film. ↓ ↓ ↓ ↓ ↓ ↓ One of Shio N wiring? J Cross-sectional view of the main part of grain 1 Fig. 3 °° Ivy cloud ξl Kikiraisuke so 1 Meng I a 8 m Fig. 4 Hagirai division 1 Kozo 1 Ru # Wearing board 0 Indicating the production m Theory B Month ErrA′J diagram

Claims (1)

[Scope of Claims] A sputtering apparatus comprising an electrode to which a high frequency is supplied in a processing chamber and an anti-adhesion plate disposed along the wall of the processing chamber serving as a counter electrode to the electrode, A sputtering device in which an insulating film is formed to a predetermined thickness.