CN1157860A

CN1157860A - Dry processing gas

Info

Publication number: CN1157860A
Application number: CN96114403A
Authority: CN
Inventors: 岩森晓; 野崎正平; 福田伸; 中岛康甫; 福田信弘
Original assignee: Mitsui Toatsu Chemicals Inc
Current assignee: Mitsui Toatsu Chemicals Inc
Priority date: 1995-09-28
Filing date: 1996-09-27
Publication date: 1997-08-27
Also published as: SG63666A1; KR100376233B1; TW365029B; KR970018175A

Abstract

The invention relates to a method of obtaining an etching gas of an electroconductive oxide suitable for high-speed anisotropic etching by including a specific compound ITO in a gas for a dry process, for etching copper and further as a gas for cleaning of a dry type etching apparatus, etc.

Description

Dry processing gas

The present invention relates to a kind of dry processing gas and for example contain CF ₃I is as a kind of etch gas of composition, the described gas of a kind of use carries out the method for dry method etch and a kind of to because of carrying out the dry method etch, the dry cleaning method of the device interior that vacuum moulding machine is polluted with other operation to conductive oxide such as indium tin oxide target (ITO).

Ito thin film has been widely used in the transparency electrode of liquid-crystal display, forms transparency electrode by the etch ito thin film.The employing wet processing that this etch is traditional.

Yet this wet method corrosion-tank finishing process makes the etch shape isotropy that becomes, thereby is difficult to process meticulous pattern.In addition, producing a large amount of waste water by processing is a problem from the viewpoint of protecting environment.

Recently by using active ion etch (RIE) to carry out the ito thin film etch, described active ion etch (RIE) is to use the RIE of hydrogen iodide (HI) gas or uses methane (CH ₄) gas and hydrogen (H ₂) RIE.

RIE method with HI has an advantage, promptly with use CH ₄And H ₂The RIE method relatively, etch rates is very fast; Yet the method with HI has a problem, and that is exactly the character owing to ito thin film, and the etch rates fluctuation is very big, particularly, as disclosing at Japanese Patent described in 251400/ ' 93, can cause in tin-oxygen key separation place the defective that etch rates reduces.

Japanese Patent discloses 251400/ ' 93 and has also described H ₂Gas adds in the HI gas as a kind of reduction initiator, and protection etch purpose surface is not covered by tin-iodine key compound.

Yet, described in disclosing, as the reduction initiator adding H of HI gas at this Japanese Patent ₂The method of gas has a restriction, i.e. etch temperature must be in 80-250 ℃ of scope.Under than the low temperature of this scope, almost can not promote etch, and etch at room temperature is difficult to carry out.

The purpose of this invention is to provide a kind of etching method, this method can prevent the etch defective that forms in wet method, and provide a kind of dry method etching method, the system that this method at room temperature is made up of HI gas and reducing gas can not promote under the situation of etch reaction, have high-speed.

Another object of the present invention provides a kind of dry cleaning method to contaminated device interior.

Further purpose of the present invention is clearer by following description meeting.

The present invention finishes on the basis of the inventor's discovery, and the inventor finds to contain CF by use ₃The etch gas of I can obtain at room temperature SnO ₂, the high speed anisotropy etch of the conductive oxide film of ITO and ZnO.

These goals of the invention can realize by following invention;

1, contain CF ₃I is as a kind of dry processing gas of composition.

2, contain CF ₃I is as a kind of composition and be applicable to the etch gas of a kind of conductive oxide of etch, is etch processing according to 1 dry process wherein.

3, the etch gas according to 2, wherein CF ₃The moisture content of I is 100ppm or still less.

4, the etch gas according to 2, wherein gas further comprises a kind of reduction composition.

5, the etch gas according to 4, wherein, the reduction composition is a hydrogen.

6, the etch gas according to 2, wherein gas further comprises fluorine gas and/or trihydrofluoride gas.

7, use a kind of dry method etching method according to etch gas etch oxide compound in the presence of argon and/or oxygen of one of 1-6.

8, according to 7 dry method etching method, wherein oxide compound is to be selected from SnO ₂, a kind of conductive oxide of ITO and ZnO.

9, according to 7 dry method etching method, wherein etch is performed such, by will be according to the CF that contains of one of 2-6 ₃The etch gas of I adds in the etch equipment and induces to discharge and carry out etch, a kind of etch target material of being made up of conductive oxide is housed in the described dry method etch equipment, described equipment is furnished with air extractor at least, the electric power application apparatus, etch target material adding apparatus, etch target material stationary installation and etch target material eduction gear.

10, contain CF ₃I is as a kind of Purge gas of composition, wherein purifies according to 1 dry process.

11, the Purge gas according to 10, wherein CF ₃The moisture content of I is 100ppm or still less.

12, a kind of dry purification method, by adding the equipment that will purify as 10 and 11 Purge gas and inducing to discharge and carry out, described Purge gas contains CF ₃I, described equipment are furnished with an air extractor and application of power device at least.

13, the dry purification method according to 12, equipment wherein to be clean is dry type etch equipment, vacuum sediment equipment, plasma CVD apparatus or spraying plating equipment.

Fig. 1 illustrates the diagram that matrix is handled in a kind of etch.

Fig. 2 is the measuring method diagram that the shape that a kind of etch processed is shown.

In these figure, the 1st, surface layer (for example, constituting) by non-corrosive metal, the 2nd, the conductive oxide film layer, the 3rd, matrix, a is the top width of the passage in conductive oxide layer, b is the bottom width of the passage in the conductive oxide layer.

CF ₃I (three fluoro-iodo-methane) is a kind of composition of dry processing gas among the present invention, and it is a kind of gas that does not fire, and molecular weight is 195.91, and boiling point-22.5 ℃ is 2.3608g/cm-32.5 ℃ of density³, at-78.5 ℃, density is 2.5485g/ cm³。

A kind of use CF is disclosed in Japanese Patent Publication 138834/ ' 80₃I is as etch gas, and a kind of polysiloxane matrix of anisotropic etch and technology that can sapping. This technology utilizes polysiloxanes and fluorine to form this fact of volatile compound.

Yet above-mentioned document is not reported fully by using CF₃I, the test of dry method etch ITO and other conductive oxide is because these oxides can not form volatile compound with fluorine.

The technology of being familiar with from those skilled in the art is different, and the inventor does not expect and can find at room temperature by using CF₃I can dry method etch ITO and other conductive oxide. In addition, the inventor finds that also preferred water content is low-level, because, when having moisture to exist, CF₃I can corroding metal. Particularly, using CF₃I is used in the situation of dry method etch or dry cleaning, CF₃The moisture of I is preferably at 100ppm or lower, more preferably 10ppm or lower, most preferably 1ppm or lower. Find, make in this way CF₃The pipeline of I gas is corroded hardly, provides good result for etch and conversion characteristic simultaneously.

In the situation of dry method etch, CF₃Contained moisture is invaded dry method etch equipment with corroded pipeline and corrosion composition and is adhered on the etch target material among the I. In addition, the CF that contains moisture₃I generates the compound that contains iodine with inwall, electrode or the reaction of etch target material of equipment, and product will adhere on the etch target material. Its result, processing characteristics such as etch rates and machining shape are adversely affected.

On the other hand, in dry cleaning, the iodine compound that contains of above-mentioned formation adheres to etch, on the inwall or electrode of spraying plating and other film former. Because this adhesion is difficult to obtain satisfied clean-up effect.

In the present invention, as described below, preferred CF in case of necessity₃The same hydrogen of I gas, fluorine gas, nitrogen fluoride and/or argon gas combine. The moisture that also requires these to add gas is the least possible, is down to CF₃In the scope of the moisture of I, preferably less than CF₃The moisture of I.

As mentioned above, it has been observed by the present inventors that, by using CF₃I gas is as etch gas, and at room temperature, exposure ITO and other conductive oxide make ito thin film and other conductive oxide film anisotropically by etch in plasma gas.

In the present invention, preferably a kind of reduction composition is joined and contain CF₃In the etch gas of I as a kind of composition, hydrogen is most preferred reducing component. Find that also when not having hydrogen or other reducing gases, etch rates is higher in the initial etch stage, As time goes on, etch rates descends gradually.

The interpolation of reducing gas has reduced the relation of etch rates and time effectively. Therefore, also find CF₃The mixing energy of I and hydrogen or other reducing gases is etch ito thin film anisotropically at a relatively high speed.

And then the inventor finds, contains CF by fluorine gas and/or gas of nitrogen trifluoride are joined₃In the etch gas of I as a kind of composition, can obtain higher etch rates.

The present invention also provides and comprises CF₃I is as a kind of Purge gas of composition.

Generally, by using dry method etch equipment, vacuum deposition device, plasma CVD apparatus and spraying plating equipment carry out the inwall of film etch or film former and/or electrode by the pollution of the raw material of etch and product. Therefore, for the product of stabilised quality is provided, the purification of equipment (chamber) is necessary. Usually, purify the general for example CF of gaseous carbon fluorine compounds that uses₄And C₂F ₆Dry cleaning finish. Yet the gaseous carbon fluorine compounds are CF for example₄And C₂F ₆Have the very high ozone layer destroying factor, this has been the target of world's control.

On the other hand, the CF that uses in the present invention₃The ozone layer destroying factor of I is 0.008 or lower, and the global warming factor is 5 or lower, therefore, and CF₃I is useful compound for earth environment. Therefore, CF₃I can be suitable for doing place of gas, to substitute for example CF of gaseous carbon fluorine compounds that tradition is used for dry cleaning₄Or C₂F ₆。

That is to say, according to the present invention, use to contain CF₃The Purge gas of I when the inwall of cleaning equipment and electrode during by these raw materials and product pollution, can be finished dry cleaning effectively. Equipment to be clean refers to dry method etch equipment, vacuum deposition device, plasma CVD apparatus or spraying plating equipment among the present invention.

Below specifically describe the present invention by the etch with ito thin film as an example.

Yet with the ito thin film of describing, the present invention uses contains CF except below₃The gas of I is to SnO₂The etch of film and ZnO film has similar action and same applicable. The inventor finds except the electric conductive oxidation beyond the region of objective existence further, and copper also can be by containing CF₃The I gas pickling. Contain CF₃The gas of I also proves to have the effect that purifies etch equipment and film former, and described equipment is by a kind of metal, metal oxide, and metal nitride, metal carbides, organic compound or siloxy group are compound polluted. To described below, be applicable to the CF that contains of etch and purification₃The condition of I gas is identical. In following concrete example, the CF of use₃The moisture of I is 1ppm or lower, analyzes with gas chromatography.

Comprise the CF as a kind of composition of the present invention₃I also is applicable to the CF that the etch gas of etch conductive oxide has₃I concentration is generally 1-100%, preferred 30-100%.

The ito thin film that is used for the target of dry method etch of the present invention is an ito thin film, the film that spraying plating forms on glass matrix for example, and its thickness is 200nm.Ito thin film is for example used non-corrosive metal patterning (patterned), and as protective layer.

Generally, the thickness that puts on applied ito thin film has no particular limits.For example, film thickness 10-500nm is preferred especially the use, because the purposes of general ito thin film is touch screen or the coloured filter as liquid crystal.Can be used for ito thin film of the present invention by various replacement glass matrixs at silicone matrix, film forming also can obtain on ceramic substrate or the plastics substrate.

Being installed in one as the ito thin film of above-mentioned formation (by using non-corrosive metal as a protective layer) has in the chamber of RF electrode of parallel-plate-type, and is used in CF ₃Cement Composite Treated by Plasma in the I air-flow and by etch.In the etch step, Cement Composite Treated by Plasma is carried out in the simultaneous air-flow of argon gas and/or oxygen preferably at reducing gas such as hydrogen.

Join CF ₃Any reducing gas in the I gas all can provide high etch rates, as long as reducing gas has also prime mover.Particularly preferred reducing gas is a hydrogen.

Argon gas joins CF ₃But accelerate dissolution indium-oxygen in the I gas, thereby can improve etch efficient.Except argon gas, found that oxygen can improve etch efficient.

The amount that adds gas can be selected arbitrarily and be not particularly limited.The flow velocity of every kind of gas (throughput ratio) and can be selected arbitrarily also without limits.

As mentioned above, the etch gas that contains reducing gas provides high etch rates.Etch rates can further increase by further interpolation fluorine gas or nitrogen trifluoride gas.

In the example as described below, with CF ₃I adds the above-mentioned hydrogen in entering the room simultaneously, argon gas, and oxygen, fluorine gas and gas of nitrogen trifluoride are imported independently by independent pipeline.Yet to this process, the method for adding without limits.Certainly, can use the gaseous mixture of two or more gas that is pre-mixed.

CF ₃The feeding rate of I gas and hydrogen or argon gas, just the throughput ratio of every kind of gas is closely related with indoor pressure.Flow velocity is had no particular limits.The flow velocity of hydrogen or argon gas is generally the 10-80% of gas overall flow rate, preferred 20-60%.The flow velocity of fluorine gas or gas of nitrogen trifluoride is preferably the 2-25% of gas overall flow rate.The too little not effect of the amount of fluorine gas or gas of nitrogen trifluoride.On the other hand, the amount of gas causes the corrosion to the chamber too greatly sometimes.The velocity ratio of gas is closely related with hole shape with the material of conductive oxide to be processed, suitably selects velocity ratio according to this relation.

Implementing under the etch situation of the present invention, the big more etch rates that causes of RF electrode power is big more.Pressure indoor during the etch is very big to the influence of etch machining shape.In order to keep the machining shape anisotropy, room pressure preferably remains on 0.1 or littler.Room pressure surpasses 0.1 torr, is easy to make the machining shape isotropy.

Further, the matrix (hereinafter referred to as substrate) that comprises conductive oxide layer can at room temperature be handled satisfactorily.Do not need heating, when needs, can adopt yet.According to the present invention, even at room temperature handle, by controlling above-mentioned etch condition, anisotropic etch also can be carried out under tens nm/min or higher speed.

The present invention can use the various etch equipment except above-mentioned parallel-plate-type RF plasma body etch equipment.Be particularly suitable for using ECR (electron cyclotron resonance etch) equipment.

According to the present invention, except the ITO conductive oxide, siloxane film at room temperature also can stand anisotropically etch at a high speed similarly.

Below will be described in further detail the present invention by example, yet these examples only are to help to understand certain embodiments of the present invention, it does not limit the scope of the invention.

Example 1

Form ito thin film thickness 200nm by spraying plating on glass matrix.(Inaonel pattern) obtains substrate as the protective layer etch on the ito thin film with the non-corrosive metal powder pattern, and Fig. 1 illustrates its sectional drawing.

Substrate places in the parallel-plate-type RF etch equipment and by following condition and carries out etch.Etch condition propulsion source high frequency 13.56MHz

400W room pressure 50mTorr gas flow rate CF ₃25 ℃ of I 100sccm substrate temperatures (constant)

The etch rates and the machining shape that obtain by this example are summarised in the table 1.

By under electron microscope, observing substrate section check etch rates.

In table 1, machining shape is by the expression of the ratio (a/b) among Fig. 2, and " a " is illustrated in the passage width of the conductive oxide of face side, and " b " is illustrated in the passage width of the conductive oxide of matrix side.

Show that by these results even at room temperature, also can obtain satisfied etch rates, machining shape also almost completely is anisotropic.Example 2

Form an ito thin film by spraying plating on glass matrix, its thickness is 200nm.By the substrate that uses non-corrosive metal powder pattern type to obtain as the protective layer etch of ito thin film, Fig. 1 illustrates its sectional drawing.

Substrate is placed in the parallel-plate-type RF etch equipment, carries out etch under following condition.Etch condition: propulsion source high frequency 13.56MHz

400W room pressure 50mTorr gas flow rate CF ₃I 60sccm

H ₂???????????????15sccm

25 ℃ of Ar 25sccm substrate temperatures (constant)

The etch rates and the machining shape that obtain in the example are summarised in the table 1.

Method assessment etch rates and etch shape according to example 1.

Show that from these results even at room temperature also can obtain satisfied etch rates, machining shape also almost completely is anisotropic.Example 3

Form SnO by spraying plating on glass matrix ₂Film, its thickness are 200 μ m, by using the non-corrosive metal powder pattern as SnO ₂The protective layer etch of film obtains substrate, and Fig. 1 illustrates its sectional drawing.

Substrate places parallel-plate-type RF etch equipment, carries out etch by following condition.Etch condition: propulsion source high frequency 13.56MHz

400W room pressure 50mTorr gas flow rate CF ₃I 50sccm

F ₂???????????????5sccm

H ₂???????????????15sccm

25 ℃ of Ar 30sccm substrate temperatures (constant)

The etch rates and the machining shape that obtain in example are summarised in the table 1.

Method assessment etch rates and etch machining shape according to example 1.

Show that from these results even also can obtain satisfied etch rates in room temperature, machining shape almost completely is anisotropic.

Example 4

Spraying plating forms a ZnO film on glass matrix, thickness 200nm.By etch obtains substrate as the ZnO film protective layer with the non-corrosive metal powder pattern, Fig. 1 illustrates its sectional drawing.

Substrate places in the flat shape template RF etch equipment, carries out etch by following condition.Etch condition: propulsion source high frequency 13.56MHz

400W room pressure 50mTorr gas flow rate CF ₃I 60sccm

NF ₃??????????????5sccm

O ₂???????????????35sccm

H ₂25 ℃ of 10sccm substrate temperatures (constant)

The etch rates and the machining shape that obtain in the example are summarized in the table 1.

Press the method assessment etch rates and the etch machining shape of example 1.

Show that by these results even at room temperature also can obtain satisfied etch rates, machining shape almost completely is anisotropic.Example 5

Spraying plating forms an ito thin film on PET matrix, and its thickness is 200nm.By etch obtains substrate as the ito thin film protective layer with the non-corrosive metal powder pattern, Fig. 1 illustrates its sectional drawing.

Substrate places in the parallel-plate-type RF etch equipment, carries out etch according to following condition.Etch condition: propulsion source high frequency 13.56MHz

400W room pressure 50mTorr gas flow rate CF ₃I 50sccm

H ₂???????????????15sccm

NF ₃??????????????10sccm

25 ℃ of Ar 25sccm substrate temperatures (constant)

The etch rates and the machining shape that obtain in the example are summarized in table 1.

Method assessment etch rates and etch machining shape by example 1.

Show that from these results even also can obtain satisfied etch rates in room temperature, machining shape almost is the different opposite sex entirely.

Example 1-5 the results are shown in table 1.

Table 1 etch rates and machining shape

Example	Etch rates (nm/min)	Etch shape (a/b)
Example	Etch rates (nm/min)	Etch shape (a/b)	????1	????350	????0.85
????2	????850	????0.90	????1	????350	????0.85
????2	????850	????0.90	????3	????300	????0.89
????4	????180	????0.90	????3	????300	????0.89
????4	????180	????0.90	????5	????1100	????0.90

Example 6

To the inwall of spraying plating equipment, with polyimide tape KAPTON (E.I.DuPont du Nemours﹠amp; Trade mark) adheres to by the thin plate that constitutes with spraying plating equipment identical materials (SUS).With a sheet glass shielding thin plate part.When feeding argon gas, distinguish seriatim at ITO SiO by spraying plating ₂, carry out film on ZnO and the Al and form operation.By this process, the equipment inwall is contaminated.Remove and adhere to the tape of thin plate to the equipment inwall thereafter.Measure pollution with the thickness telltale.Find that the thickness that film has is 92.5mm.Measure thin film composition with AES (auger electron spectroscopy method).Its result determines that the element ratio of In, Sn, Si, Zn, Cu, C, N and O is 20,5,15,5,20,15,5 and 15%.

The adhesion of film plate is adhered to situ with the polyimide tape once more, purify by following purification condition.Purification condition: propulsion source high frequency 13.56MHz

400W room pressure 1.0Torr gas flow rate CF ₃I 50sccm

H ₂???????????????15sccm

NF ₃??????????????10sccm

25 ℃ of Ar 25sccm substrate temperatures (constant)

After purifying 30 minutes under these conditions, remove the KAPTON tape once more and carry out ultimate analysis with AES.Above-mentioned I, Sn, Si, Zn and Cu do not have measured, because they are all less than determination limit.Only side goes out number of C, N and O.The CF that contains of the present invention ₃The gas cleaning effect of I can be confirmed by these results.

As mentioned above, the invention provides one at room temperature, the anisotropic etching method of high speed and be of value to the dry purification method of global environment for the conductive oxide that can not accomplish traditionally.

Claims

1. contain CF ₃I is as a kind of dry processing gas of composition.

2. contain CF ₃I is as a kind of composition and be applicable to the etch gas of etch conductive oxide, and wherein the dry process according to claim 1 is a kind of corrosion-tank finishing process.

3. according to the etch gas of claim 2, CF wherein ₃The moisture content of I is 100ppm or lower.

4. according to the etch gas of claim 2, wherein gas further comprises a kind of reduction composition.

5. according to the etch gas of claim 4, wherein reducing gas is a hydrogen.

6. according to the etch gas of claim 2, wherein gas further comprises fluorine gas and/or gas of nitrogen trifluoride.

7. a dry method etching method is used the etch gas etch oxide compound in the presence of argon and/or oxygen according to one of claim 1-6.

8. according to the dry method etch of claim 7, method wherein oxide compound is to be selected from SnO ₂, the conductive oxide of ITO and ZnO.

9. according to the dry method etching method of claim 7, wherein by will be according to the CF that contains of one of claim 2-6 ₃The etch gas of I adds in the dry method etch equipment, and by inducing discharge to carry out etch, on be set forth in the etch target material of being made up of conductive oxide be housed in the method etch equipment, described equipment is furnished with air extractor at least, the electric power application apparatus, etch target material adding apparatus, etch target material stationary installation and etch target material discharger.

10. contain CF ₃I is as a kind of Purge gas of composition, and wherein the dry process according to claim 1 is a purification process.

11. according to the Purge gas of claim 10, wherein CF ₃The moisture content of I is 100ppm or lower.

12. a dry purification method comprises by the CF that contains with claim 10 or 11 ₃I adds the equipment that will purify and induces discharge to purify as a kind of Purge gas of composition, and described equipment is furnished with air extractor and electric power application apparatus at least.

13. according to the dry purification method of claim 12, wherein the equipment that will purify is dry type etch equipment, vacuum sediment equipment, plasma CVD apparatus or spraying plating equipment.