US20040163591A1

US20040163591A1 - Coating agent, plasma-resistant component having coating film formed by the coating agent, plasma processing device provided with the plasma-resistant component

Info

Publication number: US20040163591A1
Application number: US10/477,233
Authority: US
Inventors: Nobuyuki Nagayama; Kouji Mitsuhashi; Hiroyuki Nakayama
Original assignee: Tokyo Electron Ltd
Current assignee: Tokyo Electron Ltd
Priority date: 2001-05-09
Filing date: 2002-04-03
Publication date: 2004-08-26
Also published as: US20080196744A1; CN1276478C; US7892361B2; JP2002334866A; CN1507652A; KR20040007543A; KR100628393B1; WO2002091445A1

Abstract

With a coating-film-forming coating agent 51 used as a resist including a main component such as cyclorubber-bisazide and a photosensitive component, by immersing deposits 52 deposited on the coating film of the coating agent 51 formed on an in-chamber component 50 in a release liquid such as acetone together with the in-chamber component 50 removed from within a chamber 22, the deposits 52 attached to the coating film can be removed along with the coating film from the in-chamber component 50 concurrently with the release of the coating film.

Description

FIELD OF THE INVENTION

The present invention relates to an in-chamber member, a cleaning method therefor and a plasma processing apparatus; and more particularly, to an in-chamber member to use in the chamber of a plasma processing apparatus in which plasma is excited to carry out a micro patterning process on a surface of a target object to be processed, a cleaning method therefor and a plasma processing apparatus provided with such an in-chamber member.

BACKGROUND OF THE INVENTION

In a semiconductor manufacturing process, a micro patterning process has conventionally been performed on a surface of an object to be processed such as a semiconductor wafer by means of, e.g., a plasma etching apparatus.

In such a plasma etching apparatus, an upper and a lower electrode are installed to face each other in an airtight chamber of a plasma processing vessel thereof. Mounted on the lower electrode is the object to be processed. When high frequency electric powers are applied to the upper electrode and the lower electrode, a glow discharge is induced therebetween. A process gas supplied into the chamber of the plasma processing vessel is converted into plasma by the glow discharge, which enables the object to be patterned by the plasma etching. As the process gas, a CF(Fluorocarbon)-based gas has been widely used.

The plasma processing vessel of the plasma etching apparatus is made of alumite treated Al(aluminum) employed as a base material. Further, ceramic members made of sintered Al ₂O₃(alumina) are detachably mounted on an entire inner surface of the chamber.

That is, the plasma processing vessel used in the prior art plasma etching apparatus includes an outer wall portion made of Al and an inner wall portion made of the ceramic material of Al ₂O₃(alumina), the inner wall portion being detachably mounted on the inner surface of the outer wall. Therefore, even in a case where the inner wall portion of the plasma processing vessel is abraded and damaged by plasma, restoration can be achieved by simply replacing the inner wall portion with a new one.

Further, in order to perform a desired etching process on the object in the prior art plasma etching apparatus by effectively confining the plasma between the upper electrode and the lower electrode, plasma-resistant members such as a the maintenance of the plasma processing apparatus can be facilitated.┘

(3) Page 16, line 26 of the Description has been added as follows:

┌therefor.

Further, since the coating film is separated by immersing the in-chamber member into the peeling solvent and the reaction by-products absorbed to the coating film due to the plasma process are removed from the in-chamber member together with the coating film that is being separated, it is possible to simply and quickly remove the reaction by-products from the in-chamber member of the invention.

Moreover, since the reaction by-products absorbed to the in-chamber member can be simply and quickly removed by immersing the in-chamber member into the peeling solvent, the maintenance of the plasma processing apparatus of the present invention can be facilitated.┘

(4) In page 17-1 of the Claims, claims 6 and 7 have been added as in the attached.

6. List of Attached Documents

(1) The description ( pages 1, 7, 7-1 and 16-1)

(2) The Claims (page 17-1) thereon as shown in FIG. 3B, i.e., a deposition state. When such a state is reached, the periodic cleaning work is performed. The periodic cleaning is carried out by immersing the in-

chamber member

60 in a cleaning fluid or a peeling solvent. By only immersing the in-chamber member 60 in the cleaning fluid or the like, however, deposits 61 cannot be completely removed from the in-chamber member 60 and a portion thereof remains as shown in FIG. 3C. For this reason, it is required to physically remove the residues, e.g., by using a scoop as shown in FIG. 3D or by blast.

However, in case where the residues are removed by the above-explained physical method, the number of processes of the periodic cleaning work increases to that extent, which in turn increases the time and the cost required for the cleaning work. Furthermore, there may arise a problem that the in-

chamber member

60 is physically damaged. For this reason, it may be considered to use rather stronger cleaning fluid and peeling solvent to avoid employing the physical method for removing the residues. In this case, however, there may arise another problem that the in-chamber member 60 is chemically damaged, e.g., corroded, due to the cleaning fluid and the like capable of completely eliminating the residues.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide an in-chamber member to use in the chamber of a plasma processing apparatus, for preventing damage due to plasma; and a cleaning method of the in-chamber member, for simply and quickly removing reaction by-products which are absorbed to the in-chamber member during a plasma process.

In order to achieve the object, the in-chamber member disposed in the chamber in which the plasma process is carried out includes a coating film to which the reaction by-products generated in the plasma process is absorbed, wherein the coating film is made of a resist and is separated from the in-chamber member in a peeling solvent.

Since the in-chamber member includes the coating film made of the resist, the in-chamber member can be prevented from being damaged by plasma, and since the reaction by-products generated in the plasma process are absorbed to the coating film, it is possible to remove the reaction by-products simply and quickly by separating the coating film from the in-chamber member in the peeling solvent.

Preferably, the coating film may be made of a rest part of the resist except for the photosensitive component.

Since the coating film of the in-chamber member is made of the rest part of the resist except for the photosensitive component, it is possible to reduce the cost for the formation of the coating film by as much as the cost for the photosensitive component, to thereby reduce the cost for the in-chamber member.

The object is accomplished by a method for cleaning the in-chamber member disposed in the chamber for performing the plasma process and to which the reaction by-products caused by the plasma process are absorbed, the method including the steps of: forming in advance a coating film made of a resist on a surface of the in-chamber member, and after performing the plasma process, immersing the in-chamber member in a peeling solvent to thereby remove the reaction by-products absorbed to the coating film from the in-chamber member together with the coating film that is being separated.

In accordance with the cleaning method for the in-chamber member, since the reaction by-products which are absorbed to the coating film due to the plasma process are removed together with the coating film when the coating film is separated from the in-chamber members immersed in the peeling solvent, it is possible to remove the reaction by-products from the in-chamber member simply and quickly.

Preferably, the coating film used in the cleaning method for the in-chamber member is made of a rest part of the resist except for the photosensitive component.

In accordance with the cleaning method for the in-chamber member, since coating film is made of the rest part of the resist except for the photosensitive component, it is possible to reduce the cost for the cleaning method by as much as the cost therefor.

In order to achieve the object, there is provided an in-chamber member to use in the chamber for performing a plasma process, wherein reaction by-products formed on a surface of the in-chamber member are removed by the cleaning method recited in

claim

3 or 4.

Since a coating film is separated by immersing the in-chamber member into the peeling solvent and the reaction by-products being absorbed to the coating film due to a plasma process are removed from the in-chamber member together with the coating film that is being separated, it is possible to simply and quickly remove the reaction by-products for the in-chamber member.

In order to achieve the object, there is provided a plasma processing apparatus for micro patterning a surface of an object to be processed by exciting plasma in the chamber thereof, wherein the chamber has therein the in-chamber member of

claim

5.

Since the reaction by-products absorbed to the in-chamber component can be simply and quickly removed by immersing the in-chamber member into the peeling solvent, the maintenance of the plasma processing apparatus can be facilitated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an internal structure of a plasma processing apparatus equipped with an in-chamber member in accordance with an embodiment of the present invention; [0029]
FIGS. 2A to [0030] 2E present views setting forth states of the in-chamber member to use in the plasma processing apparatus shown in FIG. 1 and a coating film thereof, wherein FIG. 2A depicts the in-chamber member before a coating agent is applied thereon; FIG. 2B offers the in-chamber member having a coating film formed by applying the coating agent thereon; FIG. 2C is a state of the in-chamber member having deposits accumulated on the coating film; FIG. 2D is a state of separating the coating film from the in-chamber member shown in FIG. 2C; and FIG. 2E is a a state where the coating film is completely removed from the in-chamber member; and
FIG. 3A to [0031] 3E offer views setting forth different states of a cleaning work of a conventional in-chamber member, wherein FIG. 3A depicts a view illustrating a state before the CF-based polymer particles are deposited on the conventional in-chamber member; FIG. 3B presents a view illustrating a state after CF-based polymer particles are deposited thereon; FIG. 3C represents a state of the conventional in-chamber member after the cleaning work; and FIG. 3D offers a view illustrating a physical removing process of residual CF-based polymer particles.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, a plasma processing apparatus provided with in-chamber members in accordance with an embodiment of the present invention will be described in detail with reference to the accompanying drawings. [0032]
FIG. 1 shows an internal structure of a plasma processing apparatus equipped with in-chamber members in accordance with the embodiment of the present invention. [0033]
A plasma processing vessel [0034] 1 of the plasma processing apparatus includes an outer wall 1 a made of alumite treated Al and an inner wall 1 b formed by a ceramic member made of Al₂O₃, the ceramic member being detachably provided on an entire inner surface of the outer wall 1 a. By being surrounded with the inner wall 1 b, an airtightly sealed chamber 22 (inside of the plasma processing vessel) is formed. In the chamber 22, an etching process is performed on a semiconductor wafer which will be described later.
In the [0035] chamber 22, in-chamber members(plasma-resistant members), e.g., an electrode protection member 8, a discharge ring 12, a focus ring 13, an insulation ring 40, a first and a second bellows cover 14, 15 and the like, exposed to the plasma environment are installed at their respective positions.
Disposed in the plasma processing vessel [0036] 1 is a lower electrode 2 made of a conductive material. Mounted on a top surface of the lower electrode 2 is an electrostatic chuck 4 for adsorbing and maintaining a semiconductor wafer 3 to be processed.
A bottom surface and a peripheral surface of the [0037] lower electrode 2 are protected by the electrode protection member 8 which is one of the in-chamber members. A lower surface 8 a and a peripheral surface of the electrode protection member 8 are covered by a conductive member 9. The conductive member 9 has an opening 9 b at a central portion of its lower surface 9 a. Formed at a central portion of the lower surface 8 a of the electrode protection member 8 exposed through the opening 9 b is an opening 8 b having an opening area smaller than that of the opening 9 b of the conductive member 9. The opening 9 b is provided with a tube-shaped member 11 passing therethrough, a leading end thereof being fixed at the lower surface 8 a of the electrode protection member 8. The tube-shaped member 11 is made of a conductive material, e.g., oxidized Al. The tube-shaped member 11 has an opening area larger than that of the opening 8 b and the leading end surrounds the opening 8 b. An elevating shaft 5 is inserted into and passes through both of the tube-shaped member 11 and the opening 8 b of the electrode protection member 8. The elevating shaft 5 is movable in a direction indicated by an arrow “A” and a leading end thereof is directly fixed to the bottom surface of the lower electrode 2. The lower electrode 2 is supported by the elevating shaft 5. The elevating shaft 5 is connected to a high frequency power source 7 via a matching unit 6 and serves as a power supply rod. Interposed between the conductive member 9 and a bottom surface of the plasma processing vessel 1 is a flexible bellows 10 made of a conductive material, e.g., stainless steel.
The [0038] discharge ring 12 is fixedly fitted around the peripheral surface of the electrode protection member 8 in a flange shape. The focus ring 13 and the insulation ring 40 are interposed between one end of the electrode protection member 8 and a peripheral surface of the electrostatic chuck 4. Further, installed at a lower surface of the discharge ring 12 is a first bellows cover 14 extending downward and erected upward at a bottom surface of the plasma processing vessel 1 is a second bellows cover 15 in such a manner that it overlaps with a portion of the first bellows cover 14.
Disposed at an upper part of the plasma processing vessel [0039] 1 is an upper electrode 16 made of a conductive material facing toward the lower electrode 2. The upper electrode 16 is provided with a plurality of gas discharge through-holes 17. A top surface of the plasma processing vessel 1 is provided with a gas supply inlet 18, which is connected to a gas supply source 21 via a mass flow controller 19 and an opening and closing valve 20. A process gas including a CF(fluorocarbon)-based gas is supplied from the gas supply source 21. Accordingly, the process gas from the gas supply source 21 is fed to the gas supply inlet 18 through the opening and closing valve 20 and the mass flow controller 19 and then is introduced into the chamber 22 via the gas discharge through-holes 17.
Provided through bottom surface of the plasma processing vessel [0040] 1 is a gas exhaust outlet 23 for exhausting the process gas, the gas exhaust outlet 23 being connected to a vacuum pump 24. In addition, an object transferring port 25 is provided through a lower side wall of the plasma processing vessel 1. The object transferring port 25 is an opening for loading the semiconductor wafer 3 to be processed into the chamber 22 or unloading the processed semiconductor wafer 3 from the chamber 22 therethrough.
Disposed around an outer circumference of the plasma processing vessel [0041] 1 is a permanent magnet 26 for generating a magnetic field along a direction parallel to a to-be-processed surface of the semiconductor wafer 3 adsorbed to the electrostatic chuck 4.
In the plasma processing apparatus having such a construction, the position of the [0042] semiconductor wafer 3 is controlled by moving the elevating shaft 5 in the direction indicated by the arrow “A” by means of a driving device(not shown). When a high frequency power of, e.g., 13.56 MHz is applied to the lower electrode 2 from the high frequency power source 7 via the elevating shaft 5, the glow discharge is generated between the lower electrode 2 and the upper electrode 16 to thereby develop an orthogonal electromagnetic field wherein an electric field and a magnetic field are orthogonal to each other.
When the [0043] chamber 22 is evacuated to a predetermined vacuum atmosphere by the vacuum pump 24 and the process gas from the gas supply source 21 is fed to the chamber 22 via the gas supply inlet 18, the process gas is converted into plasma. Subsequently, the desired micro patterning process is performed on the masked to-be-processed surface of the semiconductor wafer 3. At this time, the reaction by-products of the semiconductor wafer 3 and the CF-based gas, decomposed components and radicals of the CF-based gas generated by the plasma, and the like are produced and solid particles thereof are dispersed to be absorbed and deposited on surfaces of the in-chamber members, so that the so-called deposits are accumulated on the surfaces of the in-chamber members.
FIGS. 2A to [0044] 2E present views setting forth states of an in-chamber member to use in the plasma processing apparatus shown in FIG. 1 and a coating film thereof, wherein FIG. 2A depicts the in-chamber member before a coating agent is applied thereon; FIG. 2B offers the in-chamber member having a coating film formed by applying the coating agent thereon; FIG. 2C is a state of the in-chamber member having deposits accumulated on the coating film; FIG. 2D is a state of separating the coating film from the in-chamber member shown in FIG. 2C; and FIG. 2E is a state where the coating film is completely removed from the in-chamber member.
In FIG. 2A, there is deposited an in-[0045] chamber member 50 after the periodic cleaning work. Deposits of AlF₃particles are not left on the in-chamber member 50. As shown in FIG. 2B, a coating agent 51 is applied on the in-chamber member 50. It is not necessary to apply the coating agent 51 on an entire in-chamber member 50. The coating agent 51 may be applied only on a certain portion thereof on which the deposits will be produced. The source material of the coating agent 51 is a resist used for patterning a semiconductor wafer. After the coating agent 51 is applied on the in-chamber member 50, it is dried to form a coating film(a resist film) thereon.
Next, a main component and a photosensitive component of the resist and an organic solvent for the dissolution thereof will be exemplified. Cyclized rubber-bisazide, vinyl polycinnamate, naphthalene compound, phenolic resin, acrylic resin, novolac resin and the like may be exemplified as the main component. Diazo naphthoquinone compound, aromatic bisazide and the like can be examples of the photosensitive component. The organic solvent may be exemplified by ethyl lactate, ethyl pyruvate, xylene and the like. [0046]
When the etching process is performed in the plasma processing vessel [0047] 1, the deposits 52 are accumulated on the coating film of the coating agent 51 formed on the in-chamber member 50 as shown in FIG. 2C. When the in-chamber member 50 is cleaned by, e.g., the periodic cleaning work, the in-chamber member 50 disassembled from the chamber 22 is immersed in a peeling solvent. The peeling solvent is an organic solvent such as aceton, thinner, alcohols and the like. When the in-chamber member 50 is immersed in the peeling solvent, since the coating agent 51 is dissolved by the peeling solvent, the deposits 52 attached to the coating film of the coating agent 51 are separated from the in-chamber member 50 together with the coating film as shown in FIG. 2D. When the coating film of the coating agent 51 is separated from the in-chamber member 50, the in-chamber member 50 becomes completely clean as shown in FIG. 2E.
As described above, in accordance with the preferred embodiment of the present invention, since the coating film of the [0048] coating agent 51 formed on the in-chamber member 50 can be completely separated by immersing same in the organic solvent, e.g., acetone, thinner, alcohol and the like, it becomes very convenient. Moreover, since acetone and the like do not inflict any damage on pure aluminum, the in-chamber member 50 can be used without any concern for being damaged.
Alternatively, in lieu of the above-explained resist, a rest part of the resist excluding the photosensitive component therefrom may be used as a coating agent, which facilitates treatment of the coating agent and at the same time reduces the coat therefor. [0049]

[Industrial Applicability]

As described above, since the in-chamber members in accordance with the present invention include the coating film made of the resist, damage due to plasma can be prevented, and since the reaction by-products originated from the plasma process are absorbed to the coating film, the reaction by-products can be simply and quickly removed from the in-chamber members by separating the coating film from the in-chamber members. [0050]
Further, in case of the in-chamber members having the coating film which is made of the rest part of the resist except for the photosensitive component, the cost for the formation of the coating film can be reduced by as much as the cost for the photosensitive component, thereby reducing the cost for the in-chamber members. [0051]
Moreover, in accordance with the cleaning method for the in-chamber members, since the reaction by-products produced by the plasma process are stuck to the previously formed coating film and the coating film is separated from the in-chamber members by being immersed in the peeling solvent, the reaction by-products can be easily removed from the in-chamber members together with the coating film that is being separated. [0052]
Furthermore, in accordance with the cleaning method for the in-chamber members, since the photosensitive component is excluded from the resist, the cost for the coating method can be reduced by as much as the cost therefor. [0053]
Further, since the coating film is separated by immersing the in-chamber member into the peeling solvent and the reaction by-products absorbed to the coating film due to the plasma process are removed from the in-chamber member together with the coating film that is being separated, it is possible to simply and quickly remove the reaction by-products from the in-chamber member of the invention. [0054]
Moreover, since the reaction by-products absorbed to the in-chamber member can be simply and quickly removed by immersing the in-chamber member into the peeling solvent, the maintenance of the plasma processing apparatus of the present invention can be facilitated. [0055]

Claims

What is claimed is:

1. (Amended) An in-chamber member to use in the chamber for performing a plasma process, the in-chamber member comprising:

a coating film to which reaction by-products originated from the plasma process are absorbed, the coating film being made of a resist and separated from the in-chamber member in a peeling solvent.

2. (Amended) The in-chamber member of claim 1, wherein the coating film is made of a rest part of the resist except for a photosensitive component.

3. (Amended) A method for cleaning an in-chamber member disposed in the chamber for performing a plasma process and on which reaction by-products produced by the plasma process are absorbed, the method comprising the steps of:

forming in advance a coating film made of a resist on a surface of the in-chamber member; and

after performing the plasma process, immersing the in-chamber member into a peeling solvent to thereby remove the reaction by-products absorbed to the coating film from the in-chamber member together with the coating film that is being separated.

4. (Amended) The method of claim 3, wherein the coating film is made of a rest part of the resist except for a photosensitive component.

5. (Cancelled)

6. (New) An in-chamber member to use in the chamber for performing a plasma process, wherein reaction by-products formed on a surface of the in-chamber member is removed by the cleaning method recited in claim 3 or 4.

7. (New) A plasma processing apparatus for micro patterning a surface of an object to be processed by exciting plasma in a chamber thereof, wherein the chamber has therein the in-chamber member of claim 6.