JP2001131750A - Method for cleaning in process chamber and substrate treating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for cleaning in a process chamber capable of removing the Si-base deposits sticking to the inside of the process chamber without using costly gases and gases to affect a global warming effect and a substrate treating device. SOLUTION: In the case the cleaning process in the process chamber 2 is executed after the end of a deposition process, gaseous C4F6 is supplied to a fluorine forming section 19 and the gaseous C4F6 is irradiated with microwaves by a microwave irradiation device 18 in the state of continuing the reduced pressure evacuation of the inside of the process chamber 2 by a pump 9. At this time, the electrons e formed by the irradiation with the microwaves reacts chemically with the C4F6 and the C-F bonds of C4F6 are dissociated, by which fluorine F is formed. When this fluorine F is introduced into the process chamber 2, the fluorine F reacts chemically with the Si film and SiO2 film sticking to the inside wall, etc., of the process chamber 2 and the Si film and SiO2 film are decomposed away.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for cleaning a process chamber in a substrate processing apparatus such as a CVD apparatus and a substrate processing apparatus.

[0002]

2. Description of the Related Art A CVD apparatus, which is one of substrate processing apparatuses, includes, for example, a process chamber, a substrate support disposed in the process chamber and supporting a semiconductor wafer (substrate to be processed), and a process chamber. A pump for depressurizing and evacuating the gas, introducing a film-forming gas into the process chamber while the pressure inside the process chamber is reduced by the pump, and forming a SiO ₂ film or Si on the surface of the wafer supported by the substrate support. forming a thin film such as ₃ N ₄ film or the like.

In such a CVD apparatus, an SiO ₂ film or the like is formed on the surface of a wafer, and at the same time, such an Si film is formed on an inner wall of a process chamber or a process kit.
Often O ₂ film or the like adheres. Such Si
If the system deposits accumulate and become thicker, they may fall onto the wafer, causing particles to be generated, and as a result, the production efficiency decreases. In order to prevent such a problem, it is necessary to periodically remove Si-based deposits attached to the inner wall of the chamber, that is, to clean the inside of the process chamber.

Conventional cleaning methods include NF ₃
A gas such as a gas, a C ₂ F ₆ gas, or a CF ₄ gas is introduced into the process chamber, and high-frequency power is applied to the process chamber to generate plasma, thereby removing Si-based deposits by a sputtering action. Alternatively, there has been known a method of irradiating NF ₃ gas with microwaves to generate fluorine F, introducing the fluorine F into a process chamber, and removing Si-based deposits by a chemical reaction.

[0005]

However, NF ₃
Gas is a very expensive gas. In addition, C ₂ F ₆ gas, C
For F ₄ gas or the like, to be discharged into the atmosphere without being decomposed during the cleaning process, the influence on global warming is feared. Therefore, it is desirable not to use these gases.

An object of the present invention is to provide a method of cleaning a process chamber capable of removing Si-based deposits in a process chamber without using an expensive gas or a gas affecting global warming. And a substrate processing apparatus.

[0007]

In order to achieve the above object, a method for cleaning a process chamber according to the present invention comprises dissociating and generating fluorine from C ₄ F ₆ gas and introducing the fluorine into the process chamber. Then, the Si-based deposit attached to the inside of the process chamber is removed. For example, the generation of fluorine is performed by irradiating a C ₄ F ₆ gas with microwaves.

In the cleaning method of the present invention, C ₄ F ₆ is N
It has been made based on the finding that has a dissociation easily properties compared to F _3. When the C ₄ F ₆ gas is irradiated with microwaves as in the present invention, the generation of fluorine is promoted as compared with the case where the NF ₃ gas is irradiated with microwaves. Therefore, fluorine was introduced into the process chamber. At times, the Si-based deposits are efficiently decomposed and removed by a chemical reaction between the fluorine and the Si-based deposits deposited in the process chamber. Therefore, the inside of the process chamber can be efficiently cleaned without using an expensive gas such as NF ₃ gas or a gas that affects global warming such as C ₂ F ₆ gas or CF ₄ gas.

Preferably, as C ₄ F ₆ gas, multiple C-
A gas having a C ₄ F ₆ structure having an F bond is used. In this case, fluorine is more easily dissociated than C ₄ F ₆ .

[0010] To achieve the above object, the cleaning method of the process chamber of the present invention, C ₄ F ₆
A gas is introduced into the process chamber to generate plasma in the process chamber, thereby removing Si-based deposits attached to the process chamber.

In the cleaning method of the present invention, when C ₄ F ₆ gas is introduced into the process chamber and plasma is generated by applying, for example, high-frequency power into the process chamber, Si is generated by sputtering.
The system deposits are decomposed and removed. Therefore, without using expensive gas such as NF ₃ gas or gas that affects global warming such as C ₂ F ₆ gas and CF ₄ gas,
Cleaning inside the process chamber can be performed.

Further, in order to achieve the above object, the present invention
The cleaning method inside the process chamber is_Four
F₆Gas, CF_ThreeOCHFCF_ThreeGas, CF_ThreeCF = CF_Two
Gas, CF_ThreeCFCF_TwoO gas, CF_ThreeCOCF_ThreeGas, C
F_TwoCF_TwoOCH_TwoGas, (CF_Three)_TwoCHOH gas, CF_Three
OCF = CF_TwoGas, CF_ThreeCH_TwoOCHF_TwoGas, CHF
_TwoOCH_TwoCF_TwoCF_ThreeGas, CH_ThreeOCF_TwoCF_ThreeGas, C
F_ThreeCH_TwoOCF_TwoCF_TwoH gas, CHF_TwoOCHFCF_ThreeMoth
Dissociate and produce fluorine from one of the
Into the process chamber.
The Si-based deposits adhered to the inside are removed. this
These substances are NF_ThreeHas the property of being easily dissociated compared to
Therefore, generation of fluorine is promoted as described above, and Si
System deposits are efficiently decomposed and removed.

Further, in order to achieve the above object, a substrate processing apparatus according to the present invention includes a process chamber in which a substrate is processed and a process chamber connected to the process chamber for supplying a C ₄ F ₆ gas to the process chamber. and C ₄ F ₆ gas supply unit, C ₄ F ₆ dissociated fluorine from C ₄ F ₆ gas in the gas supply unit, a configuration and a resulting fluorine generating means. For example, the fluorine generating means is means for irradiating C ₄ F ₆ gas with microwaves.

By providing the C ₄ F ₆ gas supply unit and the fluorine generation means as described above, a cleaning method for dissociating and generating fluorine from the C ₄ F ₆ gas and introducing the generated fluorine into the process chamber as described above is performed. Therefore, Si-based deposits that have adhered to the inside of the process chamber can be removed without using expensive gas or gas that affects global warming.

[0015] To achieve the above object, a substrate processing apparatus of the present invention includes a process chamber in which substrate processing is performed, C ₄ F ₆ gas supply for supplying C ₄ F ₆ gas into the process chamber And a plasma generating means for generating plasma in the process chamber.

By providing the C ₄ F ₆ gas supply unit and the plasma generating means as described above, it is possible to implement the cleaning method of introducing the C ₄ F ₆ gas into the process chamber and generating plasma as described above. Therefore, it is possible to remove Si-based deposits deposited in the process chamber without using expensive gas or gas that affects global warming.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a method for cleaning a process chamber and a substrate processing apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of a plasma CVD apparatus which is one of the substrate processing apparatuses according to the present invention. In FIG. 1, a CVD apparatus 1 includes a process chamber 2 whose inside is depressurized. A pedestal (substrate support) 3 for supporting a silicon wafer (substrate) W is disposed in the process chamber 2, and a heater 4 for heating the wafer W is incorporated in the pedestal 3. . Above the pedestal 3, a gas distribution plate 5 is arranged parallel to the upper surface of the pedestal 3. The gas distribution plate 5 has a plurality of gas outlets 6 on its lower surface, and supplies a process gas and a cleaning gas sent from outside the process chamber 2 to the wafer W.

The gas distribution plate 5 is made of a conductive material such as aluminum and is grounded via a matching unit 7 and a high-frequency power supply 8. The pedestal 3 is also made of a conductive material such as aluminum and is grounded. Then, when the high frequency power supply 8 is turned on, for example, 13.56 MH is provided between the gas distribution plate 5 and the pedestal 3.
The high frequency power of z is applied, and plasma is generated in the process chamber 2. In the process chamber 2, the pressure inside the chamber is reduced to a desired degree of vacuum,
A pump 9 for exhausting exhaust gas generated inside the chamber is connected. In addition, as such a pump 9, a dry pump or a turbomolecular pump is used.

The CVD apparatus 1 includes a process gas supply unit 10 for supplying a process gas (film forming gas) into the process chamber 2 and a cleaning gas supply unit for supplying a cleaning gas to the process chamber 2. 11 is provided. Here, as the film forming gas, S
In order to form an iO ₂ film on the surface of the wafer W, for example, SiH ₄
A mixed gas of gas and N ₂ O gas is used. As a cleaning gas, a C ₄ F ₆ gas is used. An Ar gas is introduced into the process chamber 2 as a diluting gas together with a film forming gas.

The process gas supply unit 10 has a SiH ₄ gas supply source 12a, an N ₂ O gas supply source 12b, and an Ar gas supply source 12c.
c and the gas inlet 5a of the gas distribution plate 5 between the open / close valves 13a to 13c and the mass flow controller (M
FC) 14a to 14c are provided. Open / close valve 1
Reference numerals 3a to 13c turn on / off supply of gas from the gas supply sources 12a to 12c to the gas distribution plate 5. The MFCs 14a to 14c include gas supply sources 12a to 12c.
The flow rate of the gas supplied from c to the gas distribution plate 5 is controlled.

The cleaning gas supply unit 11 includes a C ₄ F ₆ gas supply source 15, an opening / closing valve 16 and an MFC 17 provided between the C ₄ F ₆ gas supply source 15 and the gas inlet 5 a of the gas distribution plate 5. And a microwave irradiation device 18. Microwave irradiation device 18, the fluorine generating unit 19 between the MFC17 and the gas distribution plate 5, in order to dissociate the fluorine F from C ₄ F ₆ gas, C ₄ F ₆
The C ₄ F ₆ gas sent from the gas supply source 15 is irradiated with microwaves.

When performing a film forming process using the CVD apparatus 1 configured as described above, first, the pump 9 is driven to reduce the pressure inside the process chamber 2 to a predetermined vacuum level. Next, heating of the pedestal 3 is started by the heater 4 in the pedestal 3, and the wafer W is loaded into the process chamber 2 by a wafer transfer robot (not shown), and is placed and supported on the pedestal 3.

Thereafter, SiH ₄ gas, N ₂ O gas and Ar
Gas is supplied from the gas supply sources 12 a to 12 c to the gas distribution plate 5 at a predetermined flow rate, and is introduced into the process chamber 2. When the high frequency power supply 8 is turned on, the mixed gas of the SiH ₄ gas and the N ₂ O gas ejected from the gas outlet 6 of the gas distribution plate 5 is turned into plasma between the gas distribution plate 5 and the pedestal 3. , SiH ₄ and N ₂ O
Reaches the surface of the wafer W in a state of being ionized by ions or radicals, and SiO ₂ is formed on the surface of the wafer W by a chemical reaction.
A film is formed.

Thereafter, the wafer W on which the film forming process has been completed is carried out of the process chamber 2 by a wafer transfer robot (not shown).

After performing such a film forming process on a predetermined number of wafers W, a cleaning process in the process chamber 2 according to the present invention is performed. In this cleaning process, the Si film or the S film adhered to the inner wall of the process chamber 2, the pedestal 3, or the like by the film forming process.
This is for removing the iO ₂ film (Si-based deposit).

By the way, C ₄ F ₆ used as a cleaning gas has a plurality of isomers as shown in FIG. Here, (a) is 1,1,2,3,4,4-hexafluoro-1,3-butadiene, and (b) is 1,1,1,4,4,4-hexafluoro-2-butyne. , (C) is hexafluoro-cyclobutene, (d) is 1,3,3,4,4,4-hexafluoro-1-butyne, (e) is 1-difluoromethylene, tetrafluoro-
Cyclopropane, (f) is 1-trifluoromethyl 1-2,
2,3-trifluorocyclopropane, (g) is 1,1,3,4,
4,4-Hexafluoro-1,2-butadiene, (h) is hexafluoro-bicyclo-butane, each of which has different properties. Among these C ₄ F ₆ , those having a structure of (a) to (g) having a double C—F bond or a triple C—F bond are used from the viewpoint of easy dissociation of fluorine F. Is preferred.

[0028] When performing cleaning process using such a C ₄ F ₆ gas, first, while continuing evacuation of the process chamber 2 by the pump 9, C ₄ F of C ₄ F ₆ gas supply source 15 _Six gases are supplied to the fluorine generation unit 19 at a predetermined flow rate. Then, the microwave irradiation device 18 is turned on, and the C ₄ F ₆ gas is irradiated with the microwave. At this time, the electrons e generated by the microwave irradiation are C ₄ F ₆
And the C—F bond of C ₄ F ₆ is dissociated by microwave energy to generate fluorine F.

C ₄ F ₆ + e → nC + mF The fluorine F thus generated in the fluorine generation section 19 is introduced into the process chamber 2 through the gas distribution plate 5.
Then, the Si adhered to the inner wall and the like of the process chamber 2
Fluorine F reacts with the film or SiO ₂ film as follows,
The Si film and the SiO ₂ film are decomposed and removed.

Si + 4F → SiF ₄ SiO ₂ + 4F → SiF ₄ + O ₂ Then, the SiF ₄ generated by the above chemical reaction is discharged outside the process chamber 2 as exhaust gas.

Here, C ₄ F ₆ gas, CF ₄ gas, C ₂ F ₆
Gas, SF ₆ gas, CHF ₃ gas, CCl ₂ F ₂ gas, NF
Fig. 3 shows an example of the destruction efficiency when each of the _three gases is heated.
Shown in In this figure, when the heating temperature is 600 ° C. or higher, the dissociation rate of C ₄ F ₆ is nearly 100%, and C ₄ F ₆ is N
It can be seen that as compared to the F ₃ has dissociated sensitive characteristics.

Therefore, as described above, C_FourF₆Gas to gas
When irradiating the microwave, NF _ThreeMicrowave on gas
Irradiation promotes the production of fluorine F
You. For this reason, fluorine F is introduced into the process chamber 2.
When introduced, the Si film or SiO_Two
The film is efficiently decomposed and removed.

As described above, in the present embodiment, C ₄ F ₆
Gas is irradiated with microwaves to generate fluorine F, and introducing the fluorine F in the process chamber 2, since the SiO ₂ film or the like adhering to the inner wall of the chamber or the like were to be decomposed and removed, the NF ₃ gas Without using expensive gases such as C ₂ F ₆ gas, CF ₄ gas, etc., which affect global warming, and more efficiently than in the case of using these gases. Cleaning can be performed. Also, since NF ₃ gas is not used,
The problem of mutagenicity as described for NF ₃ gas is also eliminated.

Although the present embodiment relates to the formation of a SiO ₂ film, in the case of forming a Si ₃ N ₄ film, the fluorine F adheres to the Si ₃ N ₄ film in the process chamber 2. The film reacts as follows, and the Si ₃ N ₄ film is decomposed and removed.

Si ₃ N ₄ + 12F → 3SiF ₄ + 2N ₂ Another embodiment of the method for cleaning the inside of the process chamber and the substrate processing apparatus according to the present invention will be described with reference to FIG. In the drawing, the same or equivalent members as those of the above-described embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 4, the plasma CV of this embodiment is shown.
The D device 1A is different from the cleaning gas supply unit 1 in that the microwave irradiation device 18 and the fluorine generation unit 19 shown in FIG.
The cleaning gas supply unit 11A is different from the cleaning gas supply unit 11A.

[0037] When performing a cleaning process in such a CVD apparatus 1A, by a pump 9 to the process chamber 2 while evacuating, C ₄ F ₆ gas supply source 15 C ₄ F ₆ gas into the process chamber 2 Introduce. Then, the high frequency power supply 8 is turned on to generate plasma in the process chamber 2. Then, the Si film and the SiO ₂ film adhering to the inner wall of the process chamber 2 are decomposed and removed by the sputtering action and the chemical reaction action,
It is discharged from the process chamber 2.

As described above, also in this embodiment, NF ₃
The inside of the process chamber 2 can be cleaned without using an expensive gas such as a gas or a gas that affects global warming such as a C ₂ F ₆ gas or a CF ₄ gas. In addition, in the present embodiment, since a microwave irradiation device is not required, equipment costs can be reduced.

Although the preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the above embodiments. For example, in the above embodiment, C ₄ F ₆ gas was used as the cleaning gas, but in addition to such C ₄ F ₆ gas, CF ₃ OCHFCF ₃ gas, CF ₃
CF = CF ₂ gas, CF ₃ CFCF ₂ O gas, CF ₃ COC
F ₃ gas, CF ₂ CF ₂ OCH ₂ gas, (CF ₃ ) ₂ CHOH
Gas, CF ₃ OCF = CF ₂ gas, CF ₃ CH ₂ OCHF ₂
Gas, CHF ₂ OCH ₂ CF ₂ CF ₃ gas, CH ₃ OCF ₂ C
F ₃ gas, CF ₃ CH ₂ OCF ₂ CF ₂ H gas, CHF ₂ OC
HFCF ₃ gas or the like can also be used.

Further, the above embodiment relates to a CVD apparatus, but the present invention can be applied to a substrate processing apparatus such as another film forming apparatus.

[0041]

According to the present invention, C ₄ F ₆ dissociated fluorine from the gas to produce, by introducing the fluorine in the process chamber, or remove deposits Si system or, C ₄
Since F ₆ gas was introduced into the process chamber to generate plasma and remove Si-based deposits, without using expensive gas or gas affecting global warming,
Cleaning in the process chamber can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a plasma CVD apparatus which is one of the substrate processing apparatuses according to the present invention.

FIG. 2 shows a cleaner in a process chamber according to the present invention.
C used for_FourF₆Gas C _FourF₆It is a structural formula.

FIG. 3 is a diagram showing temperature-dissociation rate characteristics of C ₄ F ₆ gas and another gas.

FIG. 4 is a schematic configuration diagram showing another embodiment of the plasma CVD apparatus according to the present invention.

[Explanation of symbols]

1, 1A: Plasma CVD apparatus (substrate processing apparatus), 2:
Process chamber, 7: Matching device (plasma generating means), 8: High-frequency power supply (plasma generating means), 9: Pump, 10: Process gas supply unit, 11, 11A: Cleaning gas supply unit (C ₄ F ₆ gas supply unit) ), 18: microwave irradiation device (fluorine generating means), W: semiconductor wafer (substrate).

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kazuo Kosuge F-term (reference) 4K030 DA06 5F045 AA06 AC02 EB06 EE06 in Nogedaira Industrial Park, 14-3 Shinizumi, Narita-shi, Chiba Pref.

Claims (9)

[Claims] 1. A method for cleaning a process chamber, wherein fluorine is dissociated and generated from a C ₄ F ₆ gas, the fluorine is introduced into the process chamber, and Si-based deposits attached to the process chamber are removed. 2. The method according to claim 1, wherein the fluorine is generated by irradiating the C ₄ F ₆ gas with a microwave. 3. A gas having a C ₄ F ₆ structure having multiple C—F bonds as the C ₄ F ₆ gas.
The method for cleaning the inside of the process chamber as described above. 4. Introducing a C ₄ F ₆ gas into the process chamber to generate a plasma in the process chamber;
A method for cleaning the inside of the process chamber for removing Si-based deposits attached to the inside of the process chamber. 5. C ₄ F ₆ gas, CF ₃ OCHFCF ₃ gas,
CF ₃ CF = CF ₂ gas, CF ₃ CFCF ₂ O gas, CF ₃
COCF ₃ gas, CF ₂ CF ₂ OCH ₂ gas, (CF ₃ ) ₂ C
HOH gas, CF ₃ OCF = CF ₂ gas, CF ₃ CH ₂ OC
HF ₂ gas, CHF ₂ OCH ₂ CF ₂ CF ₃ gas, CH ₃ OC
F ₂ CF ₃ gas, CF ₃ CH ₂ OCF ₂ CF ₂ H gas, CHF
_A method for cleaning the inside of a process chamber, wherein fluorine is dissociated and generated from one of the ₂ OCHFCF ₃ gases, the fluorine is introduced into the process chamber, and Si-based deposits attached to the process chamber are removed. And process chamber 6. The substrate processing is performed, is connected to said process chamber, and C ₄ F ₆ gas supply unit for supplying toward the C ₄ F ₆ gas into the process chamber, wherein the C ₄ F _A substrate processing apparatus comprising: a fluorine generating means for dissociating and generating fluorine from the C ₄ F ₆ gas in a ₆ gas supply unit. 7. The substrate processing apparatus according to claim ₆ , wherein said fluorine generating means is means for irradiating said C ₄ F ₆ gas with microwaves. And process chamber 8. The substrate processing is performed, C ₄ F ₆ and C ₄ F ₆ gas supply unit for supplying gas into the process chamber, a plasma generation means for generating a plasma in the process chamber A substrate processing apparatus comprising: 9. The method according to claim 6, further comprising a pump for depressurizing and evacuating the inside of the process chamber, and a process gas supply unit for supplying a process gas for performing a substrate process into the process chamber. The substrate processing apparatus according to claim 1.