JPH0212818A - Washing method of plasma processing equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] Regarding the improvement of a method for cleaning a plasma processing apparatus at least partially made of aluminum (AI), the frequency of disassembly and cleaning of the plasma processing apparatus is reduced, and cleaning is simple and low-cost. The purpose of the present invention is to provide a method for etching or ashing, which is generated by performing a process such as etching or ashing using plasma generated by exciting a gas containing oxygen in a plasma processing apparatus made of at least a portion of aluminum. The structure is configured to remove oxides or deposits by generating plasma containing hydrogen.

[Industrial application field]

The present invention relates to an improvement in a method for cleaning a plasma processing apparatus at least partially made of Al.

When plasma processing is performed using a gas containing oxygen (02) in a plasma processing apparatus that uses parts made of AI in the chamber, the surface of the parts made of An may be oxidized, and the plasma may If carbon is contained, a deposited film may be formed.

When such a deposited film is generated, active species such as oxygen atoms react on the surface or recombine and lose activity, slowing down the target processing speed or impeding the processing process. The situation may change.

Therefore, it is necessary to remove the above-mentioned AA oxide film and deposited film to stably reproduce the intended treatment process.

[Conventional technology]

Generally, in order to remove the /l oxide film or deposited film in the plasma processing equipment described above, the plasma processing equipment is disassembled and treated with an alkaline solution such as ammonia (NI13) water, acetone, or trichloride. Cleaned with organic solvents such as ethylene.

[Problem to be solved by the invention]

As mentioned above, it takes a considerable amount of time to disassemble and clean the plasma processing equipment, so it cannot be done frequently.Furthermore, when disassembling the equipment, dust is always generated and the cleanliness inside the semiconductor manufacturing factory is affected. Moreover, disassembling, cleaning, and assembling the plasma processing apparatus are quite complicated operations, and are prone to errors.

Therefore, disassembling and cleaning causes time and cost problems when mass producing semiconductor devices.

The present invention aims to reduce the frequency of disassembly and cleaning of a plasma processing apparatus, and to provide a simple and low-cost cleaning method.

[Means to solve the problem]

In the method for cleaning a plasma processing apparatus according to the present invention,
Hydrogen removes oxides or deposits generated by etching or ashing using plasma generated by exciting oxygen-containing gas in a plasma processing device that is made up of at least a portion of Al. The plasma contained therein is generated and removed.

[Effect]

By adopting the above method, the oxide on the A1 surface is modified by the reducing action of hydrogen atoms, and the etching rate of the deposit is low, but the hydrogen is
, P, As, B, F, C1°C, etc., and can be etched. Therefore, unnecessary substances generated in the plasma processing equipment can be effectively cleaned. .

〔Example〕

The figure is an explanatory view of the main parts of a plasma down flow etching apparatus (or ashing apparatus) which is an example of a plasma processing apparatus for carrying out the present invention.

In the figure, 1 is a plasma generation chamber, 2 is a gas feed pipe, and 3 is a plasma generation chamber.
is a microwave transmission window, 4 is a shower head, 5 is a processing chamber, 6 is a stage, 7 is a microwave, 8 is a plasma, 9
indicate each wafer. The inner walls of this device are all made of high-purity AI.

(1) First Example Using the illustrated apparatus, a gas mixed at CF4:400 (./min) 02:130 (cc/min) was heated under a pressure of 1 (Torr) and 2.
45 (GHz), 1. A plasma 8 is generated in the plasma generation chamber 1 by excitation with microwaves of 5 KW. Since this plasma 8 is shielded by the shower head 4, only neutral active particles can enter the processing chamber 5, where polycrystalline silicon and silicon dioxide (S
i02).

In this way, for example, when etching a polycrystalline silicon film with a thickness of 4,000 mm,
Etching is performed after processing approximately 0 wafers.
When the etching rate begins to drop and about 5,000 wafers are processed, the etching rate, which was initially about 6,000 (people/minute), drops to about 4,500 (persons/minute).

At this time, adhesion of black soot-like particles is observed inside the plasma generation chamber 1, on the microwave transmission window 3, and on the shower head 4.

Therefore, a gas mixture of H2: 300 (CC/min) and N2: 700 (cc/min) was mixed under a pressure of 1 (Torr), and 2.
45 (Gllz), 1. Plasma is generated by excitation with microwaves of 5 (KW), and 1
Washing was performed intermittently for a total of 1 [hour] at intervals of [minutes].

As a result, the etching rate of polycrystalline silicon was 57
The number of patients recovered to 00 (persons/minute).

(2) Second Example Using the illustrated apparatus, a gas mixed at Oz: 2 (71/min) and CF4: 100 (cc/min) was heated under a pressure of 1 (Torr).
A plasma 8 was generated in the plasma generation chamber 1 by excitation with microwaves of 45 (Gllz) and 1.5 (KW), and the photoresist film was ashed in the processing chamber 5.

In this case, a photoresist film having a thickness of 1 [μm] was removed. The processing speed for the first sheet is 1.5 C11
m1 minute], but the ashing rate started to decrease after processing about 500 wafers, and the ashing rate also decreased to 5000 (1 minute).
6,000 people/minute when processing about 6,000 wafers/minute
decreased rapidly to a certain extent.

Therefore, when the same cleaning as in the first example was carried out, the ashing rate was recovered to 1.1 [μm/min].

Currently, when etching polycrystalline silicon or ashing photoresist, the processing equipment is cleaned using plasma containing H2 every time 500 wafers are processed. After processing 5,000 wafers, the etching rate of polycrystalline silicon was 53
It is possible to maintain a photoresist ashing rate of about 9,000 people/minute.

The present invention is applicable not only when the plasma used for processing is 02 alone, but also when 02 and N2. N20. CF4. CHF3
．． C2F8. C3F8. NF3゜SF6. N2. N20
．． C12, CClF3. CCl2F2. C2Cl1F3
It is effective when one or more of the following are included. In addition, the plasma used for the cleaning process may not only be N2 alone, but also N2 and N2. Ar, l(e,
Xe.

It may contain one or more of Kr and the like. In this way, mixing an inert gas into H2 increases safety and facilitates handling. Note that the cleaning effect is the same as when using N2 alone.

〔Effect of the invention〕

In the method for cleaning a plasma processing apparatus of the present invention, a plasma processing apparatus, at least a part of which is made of AI, is cleaned with plasma containing N2.

By adopting such a configuration, conventionally, when etching polycrystalline silicon, disassembly and cleaning of the plasma processing apparatus was carried out every 1000 (wafers) processed.
In the present invention, 10,000 wafers are processed per process, and when photoresist is ashed, conventionally 500 wafers are processed.
It was carried out for each processing, but in this invention, 2000 (sheets)
You can significantly reduce the degree of cheekiness by just doing it every time. Note that this does not mean that cleaning according to the present invention is performed on wafers 100.
This is the case when it is executed every time [sheet] is processed.

[Brief explanation of the drawing]

The figure shows an explanatory view of the main parts of a plasma down flow etching apparatus (or ashing apparatus) which is an example of a plasma processing apparatus for carrying out the present invention. In the figure, 1 is a plasma generation chamber, 2 is a gas feed pipe, and 3 is a plasma generation chamber.
is a microwave transmission window, 4 is a shirt, - head, 5 is a processing chamber, 6 is a stage, 7 is a microwave, 8 is a plasma,
9 indicates each wafer. Patent applicant: Fujitsu Ltd. Representative Patent Attorney Shoji Aitani Representative Patent Attorney Hiroshi Watanabe - 961

Claims (1)

[Claims] Oxide or A method for cleaning a plasma processing apparatus, which includes removing deposits by generating plasma containing hydrogen.