US20020134753A1 - Vacuum processing method and vacuum processing apparatus - Google Patents
Vacuum processing method and vacuum processing apparatus Download PDFInfo
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- US20020134753A1 US20020134753A1 US10/152,001 US15200102A US2002134753A1 US 20020134753 A1 US20020134753 A1 US 20020134753A1 US 15200102 A US15200102 A US 15200102A US 2002134753 A1 US2002134753 A1 US 2002134753A1
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- processing chamber
- vacuum processing
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- radical
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- 238000003672 processing method Methods 0.000 title claims description 25
- 239000007789 gas Substances 0.000 claims abstract description 170
- 238000000034 method Methods 0.000 claims abstract description 73
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 40
- 239000001301 oxygen Substances 0.000 claims abstract description 40
- 239000011368 organic material Substances 0.000 claims abstract description 29
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 21
- 125000001153 fluoro group Chemical group F* 0.000 claims abstract description 21
- 230000003213 activating effect Effects 0.000 claims abstract description 14
- 239000000853 adhesive Substances 0.000 claims description 19
- 230000001070 adhesive effect Effects 0.000 claims description 19
- 230000001681 protective effect Effects 0.000 claims description 19
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 13
- 125000004430 oxygen atom Chemical group O* 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 6
- 238000004026 adhesive bonding Methods 0.000 claims description 2
- 239000000463 material Substances 0.000 claims description 2
- 238000005530 etching Methods 0.000 abstract description 37
- 239000011737 fluorine Substances 0.000 abstract description 7
- 238000003682 fluorination reaction Methods 0.000 abstract description 6
- 239000010408 film Substances 0.000 description 15
- 239000010410 layer Substances 0.000 description 11
- 230000002093 peripheral effect Effects 0.000 description 10
- 239000010453 quartz Substances 0.000 description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 8
- 230000001105 regulatory effect Effects 0.000 description 7
- 235000012431 wafers Nutrition 0.000 description 7
- 238000001020 plasma etching Methods 0.000 description 6
- 238000004380 ashing Methods 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 239000004642 Polyimide Substances 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 238000001312 dry etching Methods 0.000 description 4
- 229920001721 polyimide Polymers 0.000 description 4
- 238000007789 sealing Methods 0.000 description 4
- 239000010409 thin film Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 2
- 230000003628 erosive effect Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000004973 liquid crystal related substance Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000010183 spectrum analysis Methods 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
- H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
- H01L21/3065—Plasma etching; Reactive-ion etching
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
Definitions
- the present invention relates to a vacuum processing method using oxygen radicals for processing an object to be processed in a processing chamber defined by a vacuum vessel, and a vacuum processing apparatus for carrying out the same.
- object to be processed Semiconductor wafers for fabricating ICs and glass substrates for liquid crystal displays, etc. (hereinafter referred to as “object to be processed” or “object”) are processed by a process, such as an etching process or an ashing process, by a vacuum processing method using a vacuum processing apparatus.
- the vacuum processing method and the vacuum processing apparatus place an object in a processing chamber defined by a vacuum vessel and process the object in an evacuated atmosphere.
- Conventional vacuum processing methods and apparatus for carrying out the same include a chemical dry etching (CDE) method and an apparatus for carrying out the same which produce radicals in a plasma producing chamber separated from a processing chamber by activating a process gas, and introduce the radicals into the processing chamber to etch a thin film formed on a surface of the object placed in the processing chamber with the radicals.
- CDE chemical dry etching
- Conventional vacuum processing methods and apparatus for carrying out the same further include a reactive ion etching (RIE) method and an apparatus for carrying out the same which produce a plasma by applying a radio-frequency voltage to a process gas supplied into a processing chamber, and etch an object placed in the processing chamber with the plasma produced in the processing chamber, and a microwave plasma etching method and an apparatus for carrying out the same which produce a plasma by exciting a process gas supplied into a processing chamber by applying a microwave to the process gas, and etch an object placed in the processing chamber with the plasma.
- RIE reactive ion etching
- an electrostatic chuck 28 for fixedly holding an object is placed on a support surface 3 a of an object support table 3 place in a processing chamber.
- the electrostatic chuck 28 has an electrode sheet 29 , and electrode covering sheets 30 sandwiching the electrode sheet 29 therebetween.
- the electrode covering sheets 30 are formed of a heat-resistant polymer, i.e., an organic material, such as a polyimide.
- the lower electrode covering sheet 30 is bonded to the support surface 3 a of the object support table 3 with an organic adhesive 32 .
- the electrode covering sheets 30 and the adhesive 32 are formed of organic materials, portions of the electrode covering sheets 30 and the adhesive 32 exposed to an atmosphere in the processing chamber are etched by oxygen radicals for processing the object.
- the components formed of organic materials and exposed to the atmosphere in the processing chamber are etched by oxygen radicals
- the components of the vacuum processing apparatus such as the electrostatic chuck
- the vacuum processing apparatus using oxygen radicals must avoid using organic materials.
- the use of parts formed of organic materials in such an vacuum processing apparatus is unavoidable in the present circumstances because of requirements for machining parts or for the common use of parts.
- a vacuum processing method of processing an object to be processed with an oxygen radical in a processing chamber defined by a vacuum vessel of a vacuum processing apparatus comprises the steps of: fluorinating a surface of a component formed of an organic material and exposed to an atmosphere in the processing chamber with a fluorine radical produced by activating a fluorinating gas containing at least a fluorine atom with the vacuum processing apparatus before carrying the object into the processing chamber; carrying the object into the processing chamber; and processing the object with the oxygen radical produced by activating a process gas containing at least an oxygen atom.
- radical denotes a chemically highly active atom or molecule. Sometimes, radicals are referred to as ‘active species’.
- the vacuum processing apparatus comprises an object support table disposed in the processing chamber to support the object thereon, and an electrostatic chuck mounted on a surface of the object support table to hold the object on the object support table, and the electrostatic chuck comprises an electrode, and an electrode covering sheet covering the electrode.
- Theorganic material is that forming the electrode covering sheet and an organic adhesive bonding the electrostatic chuck to the surface of the object support table.
- the vacuum processing apparatus comprises an object support table disposed in the processing chamber to support the object thereon, an electrostatic chuck mounted on a surface of the object support table to hold the object on the object support table, and a protective sheet of a fluororesin covering the electrostatic chuck to protect the same.
- the organic material includes an organic adhesive used to bond the protective sheet.
- the fluorinating gas is a mixed gas including a gas containing at least a fluorine atom and an O 2 gas.
- the gas containing at least a fluorine atom is one of CF 4 , C 2 F 6 , C 3 F 8 , NF 3 and SF 6 , or a mixture of some of these gases.
- a ratio of a flow rate of the O 2 gas to a flow rate of the fluorinating gas including the O 2 gas is 40% or below.
- the process gas contains at least an O 2 gas.
- the process gas and the fluorinating gas are activated in a plasma producing chamber separated from the processing chamber, and the fluorine radical or the oxygen radical is supplied into the processing chamber.
- the object processing step processes the plurality of objects successively, and the fluorinating step is performed after the object processing step, and the object processing step and the fluorinating step are repeated alternately.
- the vacuum processing method according to the present invention fluorinates the component formed of organic material and exposed to the atmosphere in the processing chamber with the fluorine radical, and then processes the object with the oxygen radical.
- Fluorinated surface layer of the organic component serves as protective film to prevent the etching of the component formed of the organic material with an oxygen radical.
- a vacuum processing apparatus comprises: a vacuum vessel defining a processing chamber to be evacuated; radical producing means for producing a fluorine radical by activating a fluorinating gas including at least a fluorine atom and for producing an oxygen radical by activating a process gas containing at least an oxygen atom; gas supply means for supplying the fluorinating gas or the process gas to the radical producing means; and an object support table disposed in the processing chamber to support an object to be processed thereon; wherein a surface of a component formed of an organic material and exposed to an atmosphere in the processing chamber is fluorinated by the fluorine radical, and then the object is mounted on the object support table and processed with the oxygen radical.
- a vacuum processing apparatus comprises: a vacuum vessel defining a processing chamber to be evacuated; radical producing means for producing an oxygen radical by activating a process gas containing at least an oxygen atom; a gas supply means for supplying the process gas to the radical producing means; an object support table disposed in the processing chamber to support an object to be processed thereon; an electrostatic chuck mounted on a surface of the object support table to hold the object on the object support table; and a protective sheet formed of a fluororesin and covering the electrostatic chuck to protect the electrostatic chuck.
- a surface of a component formed of an organic material and exposed to an atmosphere in the processing chamber is fluorinated with a fluorine radical produced by activating a fluorinating gas containing at least a fluorine atom with the radical producing means.
- the fluorinating gas is a mixed gas including a gas containing at least a fluorine atom and an O 2 gas.
- the gas containing at least a fluorine atom is one of CF 4 , C 2 F 6 , C 3 F 8 , NF 3 and SF 6 , or a mixture of some of these gases.
- a ratio of a flow rate of the O 2 gas to a flow rate of the fluorinating gas including the O 2 gas is 40% or below.
- the process gas contains at least an O 2 gas.
- the radical producing means has a plasma producing chamber separated from the processing chamber, and the radical produced in the plasma producing chamber is supplied into the processing chamber.
- a cycle of fluorinating a component formed of an organic material and exposed to an atmosphere in the processing chamber and successively processing a plurality of objects is repeated.
- the vacuum processing apparatus fluorinates the surface of the component formed of the organic material and exposed to the atmosphere in the processing chamber with the fluorine radical, and then processes the object with the oxygen radical.
- the fluorinated surface layer of the component serves as protective film to prevent the etching of the component formed of the organic material with the oxygen radical.
- the vacuum processing apparatus is provided with the protective sheet of a fluororesin covering the electrostatic chuck. Therefore, the etching of the electrostatic chuck with the oxygen radical can be prevented by the protective sheet covering the electrostatic chuck.
- FIG. 1 is a schematic, longitudinal sectional view of chemical dry etching system (CDE system), i.e., a vacuum processing apparatus, in a preferred embodiment according to the present invention
- CDE system chemical dry etching system
- FIG. 2 is an enlarged, fragmentary, schematic longitudinal sectional view of an object support table included in the vacuum processing apparatus shown in FIG. 1;
- FIG. 3 is a table showing the results of comparative experiments conducted to demonstrate the protective effect of fluorination on protecting organic components
- FIG. 4 is a graph showing etching rate, and O/F radical ratio determined by emission spectral analysis when a component formed of an organic material is etched with a mixed gas containing CF 4 and O 2 ;
- FIG. 5 is a graph showing the dependence of fluorinating rate on O 2 /(O 2 +CF 4 ) flow rate ratio when an organic film is fluorinated with a mixed gas containing CF 4 and O 2 by the CDE system shown in FIG. 1;
- FIG. 6 is an enlarged, fragmentary, schematic longitudinal sectional view of an object support table included in a conventional vacuum processing apparatus.
- FIG. 1 shows a downflow chemical dry etching system (CDE system) as an example of a vacuum processing apparatus for carrying out a vacuum processing method embodying the present invention.
- CDE system downflow chemical dry etching system
- the CDE system has a vacuum vessel 1 defining a processing chamber 2 , and an object support table 3 disposed in the processing chamber 2 .
- a object S is supported on the object support table 3 .
- the object support table 3 is provided with a temperature regulator, not shown.
- the temperature of the object S can be regulated by the temperature regulator.
- the vacuum vessel 1 has a bottom wall 4 provided with gas outlet openings 5 .
- Each of discharge pipes 6 has one end connected to a vacuum pump, not shown, and the other end connected to the outlet opening 5 .
- the vacuum vessel 1 has a top wall 7 provided with a gas inlet opening 8 .
- a gas supply pipe 9 formed of a fluororesin is connected to the gas inlet opening 8 .
- a quartz pipe 10 has one end connected to the gas supply pipe 9 and the other end sealed by a sealing member 11 internally provided with a gas passage 19 .
- a gas supply pipe 18 has one end connected to the sealing member 11 and the other end connected to branch pipes 20 and 21 .
- the branch pipes 20 and 21 are connected to a first gas cylinder 23 provided with a first flow regulating valve 22 and a second gas cylinder 25 provided with a second flow regulating valve 24 , respectively.
- the first gas cylinder 23 and the second gas cylinder 25 constitute a gas supply source (gas supply means) 26 .
- the first gas cylinder 23 contains a gas containing at least fluorine atoms, preferably, one of CF 4 , C 2 F 6 , C 3 F 8 , NF 3 and SF 6 , or a mixture of some of these gases.
- the second gas cylinder 25 contains a gas containing at least oxygen atoms, preferably, a gas containing at least O 2 gas.
- a plasma producing device (radical producing means) 13 provided with a waveguide 12 is combined with the quartz pipe 10 so as to surround a section of the quartz pipe 10 .
- a plasma producing chamber 14 is formed in the section of the quartz pipe 10 surrounded by the plasma producing device 13 .
- a microwave generator 27 is connected to the waveguide 12 .
- a shower plate 16 provided with a plurality of gas jetting holes 17 is placed in the processing chamber 2 so as to form a gas storage chamber 15 above the processing chamber 2 to distribute radicals supplied into the processing chamber 2 uniformly over the entire surface of the object S.
- FIG. 2 is an enlarged, fragmentary, schematic longitudinal sectional view of the object support table 3 of the CDE system shown in FIG. 1.
- an electrostatic chuck 28 for fixedly holding the object S by electrostatic attraction is placed on a support surface 3 a of the object support table 3 .
- the electrostatic chuck 28 has an electrode sheet 29 of a conductive material, such as copper, and electrode covering sheets 30 sandwiching the electrode sheet 29 therebetween.
- the electrode covering sheets 30 are formed of a heat-resistant polymer, i.e., an organic material, such as a polyimide.
- the lower electrode covering sheet 30 is bonded to the support surface 3 a of the object support table 3 with an organic adhesive 32 .
- the electrostatic chuck 28 is covered with a protective sheet 31 .
- the protective sheet 31 is formed of a fluororesin. Since the electrode covering sheets 30 of an organic material are covered with the protective sheet 31 , the erosion of the surfaces of the electrode covering sheets 30 by the etching action of oxygen radicals which are used for etching the object S can be processed.
- the protective sheet 31 is bonded to the surface of the upper electrode covering sheet 30 of the electrostatic chuck 28 and to a peripheral region of the support surface 3 a of the object support table 3 with the organic adhesive 32 .
- the peripheral surface 33 of the layer of the organic adhesive 32 is exposed to an atmosphere in the processing chamber 2 (FIG. 1). Therefore, the peripheral surface 33 of the layer of the organic adhesive 32 is subject to erosion by etching while the object S is processed with oxygen radicals unless the some measures are taken to protect the peripheral surface 33 .
- the vacuum processing method and the apparatus embodying the present invention evacuates the vacuum vessel 1 to a vacuum (reduced pressure) by removing gases and vapors through the outlet openings 5 and the discharge pipes 6 by the vacuum pump before carrying the object S into the processing chamber 2 .
- the gas containing at least fluorine atoms is supplied from the first gas cylinder 23 through the branch pipe 20 , the gas supply pipe 18 and the gas passage of the sealing member 11 into the quartz pipe 10 .
- the gas contained at least oxygen atoms is supplied from the second gas cylinder 25 .
- the first flow regulating valve 22 and the second flow regulating valve 24 are adjusted so that the gas containing at least fluorine atoms and the gas containing at least oxygen atoms are supplied at flow rates and flow rate ratios suitable for fluorinating the organic components.
- Microwaves generated by the microwave generator 27 are guided by the waveguide 12 of the plasma producing device 13 into the plasma producing chamber 14 . Consequently, glow discharge is generated in the plasma producing chamber 14 and a plasma P is produced, whereby fluorine contained in the mixed gas for fluorination is excited and fluorine radicals are produced.
- the fluorinating gas containing fluorine radicals is supplied through the quartz pipe 10 , the gas supply pipe 9 and the gas inlet opening 8 into the gas storage chamber 15 . Then, the fluorinating gas is jetted from the gas storage chamber 15 through the gas jetting holes 17 so as to be uniformly distributed in the processing chamber 2 by pressure difference between the gas storage chamber 15 and the processing chamber 2 .
- Fluorine radicals thus supplied into the processing chamber 2 fluorinate, for example, the peripheral surface 33 of the layer of the organic adhesive 32 , i.e., a surface of an organic component exposed to an atmosphere in the processing chamber 2 .
- the fluorinating gas reacted with the peripheral surface 33 of the layer of the organic adhesive 32 is discharged through the gas outlet openings 5 and the discharge pipes 6 by the vacuum pump.
- Such a fluorinating process is continued for a time necessary to form a fluorinated film of a desired thickness. Then, the supply of the gases from the first gas cylinder 23 and the second gas cylinder 25 is stopped, and the object S is carried into the processing chamber 2 . Subsequently, the gas containing at least oxygen atoms is supplied through the branch pipe 21 , the gas supply pipe 18 and the gas passage 19 of the sealing member 11 into the quartz pipe 10 . At the same time, the gas containing at least fluorine atoms is supplied from the first gas cylinder 23 . The first flow regulating valve 22 and the second flow regulating valve 24 are adjusted so that the gas containing at least fluorine atoms and the gas containing at least oxygen atoms are supplied at flow rates and flow rate ratios suitable for etching the object S.
- Microwaves generated by the microwave generator 27 are guided by the waveguide 12 of the plasma producing device 13 into the plasma producing chamber 14 . Consequently, glow discharge is generated in the plasma producing chamber 14 and a plasma P is produced, whereby oxygen contained in the process gas, i.e., a mixed gas of the gas containing at least oxygen atoms and the gas containing at least fluorine atoms, is excited and oxygen radicals are produced.
- the process gas i.e., a mixed gas of the gas containing at least oxygen atoms and the gas containing at least fluorine atoms
- the process gas containing oxygen radicals is supplied through the quartz pipe 10 , the gas supply pipe 9 and the gas inlet opening 8 into the gas storage chamber 15 . Then, the process gas is jetted from the gas storage chamber 15 through the gas jetting holes 17 so as to be uniformly distributed in the processing chamber 2 by pressure difference between the gas storage chamber 15 and the processing chamber 2 .
- oxygen radicals thus supplied into the processing chamber 2 reacts with a thin film formed on a surface of the object S to etch the thin film by an etching process.
- the process gas reacted with the thin film formed on the surface of the object S is discharged through the gas outlet openings 5 and the discharge pipes 6 by the vacuum pump.
- the oxygen radicals supplied into the processing chamber 2 reach, for example, the peripheral surface 33 of the layer of the organic adhesive 32 , i.e., a surface of an organic component exposed to the atmosphere of the processing chamber 2 .
- the etching of the peripheral surface 33 of the layer of the organic adhesive 32 and the like by the oxygen radicals is limited to the least unavoidable extent and are etched very little because the peripheral surface 33 of the layer of the organic adhesive 32 and the like are fluorinated beforehand.
- the etching process stopped after successively etching several or several tens of objects S, and the fluorinating process is performed after removing the last object S from the object support table 3 to fluorinate the surfaces of the organic components again. Then, the etching process is resumed. Thus, the fluorinating process and the etching process are repeated alternately to process several or several tens of objects S successively after fluorinating the surfaces of the organic components.
- the fluorinating gas is one of CF 4 , C 2 F 6 , C 3 F 8 , NF 3 and SF 6 , or a mixture of some of these gases.
- the process gas is a gas containing at least O 2 gas.
- the electrostatic chuck 28 of the vacuum processing apparatus in the foregoing embodiment is covered with the protective sheet 31
- the present invention may be embodied by a vacuum processing method and an apparatus provided with the electrostatic chuck 28 not covered with any sheet corresponding to the protective sheet 31 .
- the surface of the electrode covering sheet 30 formed of an polyimide and the exposed surface of the layer of the organic adhesive 32 are fluorinated by a fluorinating process similar to that described above before an object S is mounted on the object support table 3 .
- the etching of the electrode covering sheet 30 and the surface of the layer of the organic adhesive 32 with oxygen radicals can be prevented in the etching process for etching the object S with oxygen radicals.
- FIG. 3 shows the results of comparative experiments conducted by using the CDE system shown in FIG. 1 to demonstrate the protective effect of the fluorinating process on protecting organic components.
- Wafers provided with a carbon film, i.e., an organic film was used as samples.
- the experiments demonstrate the effect of the fluorinating process on the organic films formed on the surfaces of the wafers, the effect holds true for the organic components of the walls of the vacuum vessel 1 and the object support table 3 , such as the layer of the organic adhesive and the sheet of a polyimide.
- FIG. 3 the result of experiments in which the fluorinating process was omitted and the sample wafer was subjected to an etching process for 60 min is shown in an upper section.
- the etching process used an etching gas containing one part CF 4 gas and three parts O 2 gas and microwaves of 450 W in power.
- the processing chamber 2 was evacuated at 40 Pa and the object support table 3 was kept at 5° C.
- the carbon film was etched by a depth of 3.9 ⁇ m.
- the result of experiments in which the sample wafer was subjected to the fluorinating process and the same etching process of the foregoing conditions is shown in a lower section in FIG. 3.
- the fluorinating process used a mixed gas containing three parts CF 4 gas and one part O 2 gas.
- the etching process used an etching gas containing one part CF 4 gas and three parts O 2 gas and microwaves of 700 W in power.
- the processing chamber was evacuated at 40 Pa and the object support table 3 was kept at 5° C. for the fluorinating process. After the fluorinating process, the sample wafer was subjected to the etching process.
- the carbon film was etched by a depth of only 0.5 ⁇ m, which proved the great effect of fluorination on the suppression of etching of the carbon film by oxygen radicals.
- FIG. 4 is a graph showing etching rate, and O/F radical ratio determined by emission spectral analysis when a film of an organic material was etched with a mixed gas containing CF 4 and O 2
- 0 2 /( 0 2 +CF 4 ) flow rate ratio i.e., the ratio of the flow rate of O 2 gas to the flow rate of the mixed gas ( 0 2 +CF 4 ) is measured on the horizontal axis.
- the O/F radical ratio i.e., the ratio of the amount of oxygen radicals to that of fluorine radicals produced, and etch rate at which the organic film is etched is increasing along with the increase of O 2 /( 0 2 +CF 4 ) flow rate ratio.
- FIG. 5 is a graph showing the dependence of fluorinating rate on O 2 /(O 2 +CF 4 ) flow rate ratio, i.e., the ratio of flow rate of O 2 gas to that of the mixed gas containing O 2 gas and CF 4 gas, when an organic film is fluorinated with the mixed gas containing CF 4 and O 2 by the CDE system shown in FIG. 1.
- the organic film is scarcely fluorinated when the O 2 /(O 2 +CF 4 ) flow rate ratio is greater than 40%.
- a preferable O 2 /(O 2 +CF 4 ) flow rate ratio is not greater than 40%.
- the vacuum processing method and the apparatus for carrying the same embodying the present invention fluorinate the surfaces of the organic components exposed to the atmosphere in the processing chamber 2 with fluorine radicals in the fluorinating process, and then etches the object S with oxygen radicals in the etching process. Therefore, etching of the organic components with oxygen radicals can be prevented.
- the electrostatic chuck 28 is covered with and protected by the protective sheet 31 of a fluororesin, etching of the electrode covering sheets 30 of the electrostatic chuck 28 with oxygen radicals can be prevented.
- the fluorinating process for fluorinating the organic components can be achieved by the vacuum processing apparatus, any special apparatus for the fluorination of the organic components is unnecessary, and the members requiring fluorination by the fluorinating process need not be removed from the vacuum processing apparatus.
- the present invention is not limited in its practical application to the foregoing CDE method and the CDE system, and is applicable to various vacuum processing methods and vacuum processing apparatus which process objects in a vacuum atmosphere. More concretely, the present invention is applicable to dry etching methods and apparatus for carrying out the same, such as reactive ion etching (RIE) methods and apparatus for carrying out the same and microwave plasma etching methods and apparatus for carrying out the same, or ashing methods and apparatus for carrying out the same.
- RIE reactive ion etching
- the present invention can be applied to an etching/ashing process for etching/ashing semiconductor wafers for fabricating ICs and glass substrates for liquid crystal displays.
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Abstract
A vacuum processing apparatus produces fluorine radicals by activating a fluorinating gas containing at least fluorine atoms and fluorinates the surface of a component formed of an organic material (32) exposed to an atmosphere of a processing chamber (2) before carrying an object (S) into the processing chamber (2). The object (S) is carried into the processing chamber (2) after the completion of a fluorinating process. The object (S) is processed with a processing gas containing at least oxygen radicals. Etching of the component formed of the organic material (32) can be prevented by the fluorination of surface of the component formed of the organic material (32) and exposed to an atmosphere in the processing chamber (2).
Description
- The present invention relates to a vacuum processing method using oxygen radicals for processing an object to be processed in a processing chamber defined by a vacuum vessel, and a vacuum processing apparatus for carrying out the same.
- Semiconductor wafers for fabricating ICs and glass substrates for liquid crystal displays, etc. (hereinafter referred to as “object to be processed” or “object”) are processed by a process, such as an etching process or an ashing process, by a vacuum processing method using a vacuum processing apparatus. The vacuum processing method and the vacuum processing apparatus place an object in a processing chamber defined by a vacuum vessel and process the object in an evacuated atmosphere.
- Conventional vacuum processing methods and apparatus for carrying out the same include a chemical dry etching (CDE) method and an apparatus for carrying out the same which produce radicals in a plasma producing chamber separated from a processing chamber by activating a process gas, and introduce the radicals into the processing chamber to etch a thin film formed on a surface of the object placed in the processing chamber with the radicals.
- Conventional vacuum processing methods and apparatus for carrying out the same further include a reactive ion etching (RIE) method and an apparatus for carrying out the same which produce a plasma by applying a radio-frequency voltage to a process gas supplied into a processing chamber, and etch an object placed in the processing chamber with the plasma produced in the processing chamber, and a microwave plasma etching method and an apparatus for carrying out the same which produce a plasma by exciting a process gas supplied into a processing chamber by applying a microwave to the process gas, and etch an object placed in the processing chamber with the plasma.
- When an object is processed with oxygen radicals by the conventional vacuum processing method and the apparatus for carrying out the same, organic structural members and organic adhesives are etched if they are exposed to oxygen radicals in the processing chamber.
- Referring to FIG. 6, an
electrostatic chuck 28 for fixedly holding an object is placed on asupport surface 3 a of an object support table 3 place in a processing chamber. Theelectrostatic chuck 28 has anelectrode sheet 29, andelectrode covering sheets 30 sandwiching theelectrode sheet 29 therebetween. - The
electrode covering sheets 30 are formed of a heat-resistant polymer, i.e., an organic material, such as a polyimide. The lowerelectrode covering sheet 30 is bonded to thesupport surface 3 a of the object support table 3 with anorganic adhesive 32. - Since the
electrode covering sheets 30 and the adhesive 32 are formed of organic materials, portions of theelectrode covering sheets 30 and theadhesive 32 exposed to an atmosphere in the processing chamber are etched by oxygen radicals for processing the object. - Since the components formed of organic materials and exposed to the atmosphere in the processing chamber are etched by oxygen radicals, the components of the vacuum processing apparatus, such as the electrostatic chuck, are short-lived and are sources of particles that reduces the yield of products. Essentially, the vacuum processing apparatus using oxygen radicals must avoid using organic materials. However, the use of parts formed of organic materials in such an vacuum processing apparatus is unavoidable in the present circumstances because of requirements for machining parts or for the common use of parts.
- Accordingly, it is an object of the present invention to provide a vacuum processing method and an apparatus for carrying out the same capable of preventing the etching of parts formed of organic materials and exposed to an atmosphere in a processing chamber even when an object is processed with oxygen radicals.
- According to the present invention, a vacuum processing method of processing an object to be processed with an oxygen radical in a processing chamber defined by a vacuum vessel of a vacuum processing apparatus comprises the steps of: fluorinating a surface of a component formed of an organic material and exposed to an atmosphere in the processing chamber with a fluorine radical produced by activating a fluorinating gas containing at least a fluorine atom with the vacuum processing apparatus before carrying the object into the processing chamber; carrying the object into the processing chamber; and processing the object with the oxygen radical produced by activating a process gas containing at least an oxygen atom.
- The term ‘radical’ as used in the description denotes a chemically highly active atom or molecule. Sometimes, radicals are referred to as ‘active species’.
- Preferably, the vacuum processing apparatus comprises an object support table disposed in the processing chamber to support the object thereon, and an electrostatic chuck mounted on a surface of the object support table to hold the object on the object support table, and the electrostatic chuck comprises an electrode, and an electrode covering sheet covering the electrode. Theorganic material is that forming the electrode covering sheet and an organic adhesive bonding the electrostatic chuck to the surface of the object support table.
- Preferably, the vacuum processing apparatus comprises an object support table disposed in the processing chamber to support the object thereon, an electrostatic chuck mounted on a surface of the object support table to hold the object on the object support table, and a protective sheet of a fluororesin covering the electrostatic chuck to protect the same. The organic material includes an organic adhesive used to bond the protective sheet.
- Preferably, the fluorinating gas is a mixed gas including a gas containing at least a fluorine atom and an O2 gas.
- Preferably, the gas containing at least a fluorine atom is one of CF4, C2F6, C3F8, NF3 and SF6, or a mixture of some of these gases.
- Preferably, a ratio of a flow rate of the O2 gas to a flow rate of the fluorinating gas including the O2 gas is 40% or below.
- Preferably, the process gas contains at least an O2 gas.
- Preferably, the process gas and the fluorinating gas are activated in a plasma producing chamber separated from the processing chamber, and the fluorine radical or the oxygen radical is supplied into the processing chamber.
- Preferably, the object processing step processes the plurality of objects successively, and the fluorinating step is performed after the object processing step, and the object processing step and the fluorinating step are repeated alternately.
- The vacuum processing method according to the present invention fluorinates the component formed of organic material and exposed to the atmosphere in the processing chamber with the fluorine radical, and then processes the object with the oxygen radical. Fluorinated surface layer of the organic component serves as protective film to prevent the etching of the component formed of the organic material with an oxygen radical.
- A vacuum processing apparatus according to the present invention comprises: a vacuum vessel defining a processing chamber to be evacuated; radical producing means for producing a fluorine radical by activating a fluorinating gas including at least a fluorine atom and for producing an oxygen radical by activating a process gas containing at least an oxygen atom; gas supply means for supplying the fluorinating gas or the process gas to the radical producing means; and an object support table disposed in the processing chamber to support an object to be processed thereon; wherein a surface of a component formed of an organic material and exposed to an atmosphere in the processing chamber is fluorinated by the fluorine radical, and then the object is mounted on the object support table and processed with the oxygen radical.
- A vacuum processing apparatus according to the present invention comprises: a vacuum vessel defining a processing chamber to be evacuated; radical producing means for producing an oxygen radical by activating a process gas containing at least an oxygen atom; a gas supply means for supplying the process gas to the radical producing means; an object support table disposed in the processing chamber to support an object to be processed thereon; an electrostatic chuck mounted on a surface of the object support table to hold the object on the object support table; and a protective sheet formed of a fluororesin and covering the electrostatic chuck to protect the electrostatic chuck.
- Preferably, a surface of a component formed of an organic material and exposed to an atmosphere in the processing chamber is fluorinated with a fluorine radical produced by activating a fluorinating gas containing at least a fluorine atom with the radical producing means.
- Preferably, the fluorinating gas is a mixed gas including a gas containing at least a fluorine atom and an O2 gas.
- Preferably, the gas containing at least a fluorine atom is one of CF4, C2F6, C3F8, NF3 and SF6, or a mixture of some of these gases.
- Preferably, a ratio of a flow rate of the O2 gas to a flow rate of the fluorinating gas including the O2 gas is 40% or below.
- Preferably, the process gas contains at least an O2 gas.
- Preferably, the radical producing means has a plasma producing chamber separated from the processing chamber, and the radical produced in the plasma producing chamber is supplied into the processing chamber.
- Preferably, a cycle of fluorinating a component formed of an organic material and exposed to an atmosphere in the processing chamber and successively processing a plurality of objects is repeated.
- The vacuum processing apparatus according to the present invention fluorinates the surface of the component formed of the organic material and exposed to the atmosphere in the processing chamber with the fluorine radical, and then processes the object with the oxygen radical. The fluorinated surface layer of the component serves as protective film to prevent the etching of the component formed of the organic material with the oxygen radical.
- The vacuum processing apparatus according to the present invention is provided with the protective sheet of a fluororesin covering the electrostatic chuck. Therefore, the etching of the electrostatic chuck with the oxygen radical can be prevented by the protective sheet covering the electrostatic chuck.
- FIG. 1 is a schematic, longitudinal sectional view of chemical dry etching system (CDE system), i.e., a vacuum processing apparatus, in a preferred embodiment according to the present invention;
- FIG. 2 is an enlarged, fragmentary, schematic longitudinal sectional view of an object support table included in the vacuum processing apparatus shown in FIG. 1;
- FIG. 3 is a table showing the results of comparative experiments conducted to demonstrate the protective effect of fluorination on protecting organic components;
- FIG. 4 is a graph showing etching rate, and O/F radical ratio determined by emission spectral analysis when a component formed of an organic material is etched with a mixed gas containing CF4 and O2;
- FIG. 5 is a graph showing the dependence of fluorinating rate on O2/(O2+CF4) flow rate ratio when an organic film is fluorinated with a mixed gas containing CF4 and O2 by the CDE system shown in FIG. 1; and
- FIG. 6 is an enlarged, fragmentary, schematic longitudinal sectional view of an object support table included in a conventional vacuum processing apparatus.
- A vacuum processing method and an apparatus for carrying out the same embodying the present invention will be described hereinafter with reference to the accompanying drawings.
- FIG. 1 shows a downflow chemical dry etching system (CDE system) as an example of a vacuum processing apparatus for carrying out a vacuum processing method embodying the present invention.
- Referring to FIG. 1, the CDE system has a
vacuum vessel 1 defining aprocessing chamber 2, and an object support table 3 disposed in theprocessing chamber 2. A object S is supported on the object support table 3. The object support table 3 is provided with a temperature regulator, not shown. - The temperature of the object S can be regulated by the temperature regulator.
- The
vacuum vessel 1 has abottom wall 4 provided withgas outlet openings 5. Each ofdischarge pipes 6 has one end connected to a vacuum pump, not shown, and the other end connected to the outlet opening 5. Thevacuum vessel 1 has atop wall 7 provided with a gas inlet opening 8. Agas supply pipe 9 formed of a fluororesin is connected to the gas inlet opening 8. Aquartz pipe 10 has one end connected to thegas supply pipe 9 and the other end sealed by a sealingmember 11 internally provided with agas passage 19. Agas supply pipe 18 has one end connected to the sealingmember 11 and the other end connected to branchpipes - The
branch pipes first gas cylinder 23 provided with a firstflow regulating valve 22 and asecond gas cylinder 25 provided with a secondflow regulating valve 24, respectively. Thefirst gas cylinder 23 and thesecond gas cylinder 25 constitute a gas supply source (gas supply means) 26. - The
first gas cylinder 23 contains a gas containing at least fluorine atoms, preferably, one of CF4, C2F6, C3F8, NF3 and SF6, or a mixture of some of these gases. Thesecond gas cylinder 25 contains a gas containing at least oxygen atoms, preferably, a gas containing at least O2 gas. - A plasma producing device (radical producing means)13 provided with a
waveguide 12 is combined with thequartz pipe 10 so as to surround a section of thequartz pipe 10. Aplasma producing chamber 14 is formed in the section of thequartz pipe 10 surrounded by theplasma producing device 13. Amicrowave generator 27 is connected to thewaveguide 12. - A
shower plate 16 provided with a plurality of gas jetting holes 17 is placed in theprocessing chamber 2 so as to form agas storage chamber 15 above theprocessing chamber 2 to distribute radicals supplied into theprocessing chamber 2 uniformly over the entire surface of the object S. - FIG. 2 is an enlarged, fragmentary, schematic longitudinal sectional view of the object support table 3 of the CDE system shown in FIG. 1. As shown in FIG. 2, an
electrostatic chuck 28 for fixedly holding the object S by electrostatic attraction is placed on asupport surface 3 a of the object support table 3. Theelectrostatic chuck 28 has anelectrode sheet 29 of a conductive material, such as copper, andelectrode covering sheets 30 sandwiching theelectrode sheet 29 therebetween. Theelectrode covering sheets 30 are formed of a heat-resistant polymer, i.e., an organic material, such as a polyimide. The lowerelectrode covering sheet 30 is bonded to thesupport surface 3 a of the object support table 3 with anorganic adhesive 32. - The
electrostatic chuck 28 is covered with aprotective sheet 31. Preferably, theprotective sheet 31 is formed of a fluororesin. Since theelectrode covering sheets 30 of an organic material are covered with theprotective sheet 31, the erosion of the surfaces of theelectrode covering sheets 30 by the etching action of oxygen radicals which are used for etching the object S can be processed. - The
protective sheet 31 is bonded to the surface of the upperelectrode covering sheet 30 of theelectrostatic chuck 28 and to a peripheral region of thesupport surface 3 a of the object support table 3 with theorganic adhesive 32. Theperipheral surface 33 of the layer of theorganic adhesive 32 is exposed to an atmosphere in the processing chamber 2 (FIG. 1). Therefore, theperipheral surface 33 of the layer of theorganic adhesive 32 is subject to erosion by etching while the object S is processed with oxygen radicals unless the some measures are taken to protect theperipheral surface 33. - Some parts of components formed of organic materials are exposed, for example, on the inner surface of the
vacuum vessel 1 in addition to theperipheral surface 33 of the layer of theorganic adhesive 32. - The vacuum processing method and the apparatus embodying the present invention evacuates the
vacuum vessel 1 to a vacuum (reduced pressure) by removing gases and vapors through theoutlet openings 5 and thedischarge pipes 6 by the vacuum pump before carrying the object S into theprocessing chamber 2. - The gas containing at least fluorine atoms is supplied from the
first gas cylinder 23 through thebranch pipe 20, thegas supply pipe 18 and the gas passage of the sealingmember 11 into thequartz pipe 10. At the same time, the gas contained at least oxygen atoms is supplied from thesecond gas cylinder 25. The firstflow regulating valve 22 and the secondflow regulating valve 24 are adjusted so that the gas containing at least fluorine atoms and the gas containing at least oxygen atoms are supplied at flow rates and flow rate ratios suitable for fluorinating the organic components. - Microwaves generated by the
microwave generator 27 are guided by thewaveguide 12 of theplasma producing device 13 into theplasma producing chamber 14. Consequently, glow discharge is generated in theplasma producing chamber 14 and a plasma P is produced, whereby fluorine contained in the mixed gas for fluorination is excited and fluorine radicals are produced. - The fluorinating gas containing fluorine radicals is supplied through the
quartz pipe 10, thegas supply pipe 9 and the gas inlet opening 8 into thegas storage chamber 15. Then, the fluorinating gas is jetted from thegas storage chamber 15 through the gas jetting holes 17 so as to be uniformly distributed in theprocessing chamber 2 by pressure difference between thegas storage chamber 15 and theprocessing chamber 2. - Fluorine radicals thus supplied into the
processing chamber 2 fluorinate, for example, theperipheral surface 33 of the layer of theorganic adhesive 32, i.e., a surface of an organic component exposed to an atmosphere in theprocessing chamber 2. The fluorinating gas reacted with theperipheral surface 33 of the layer of theorganic adhesive 32 is discharged through thegas outlet openings 5 and thedischarge pipes 6 by the vacuum pump. - Such a fluorinating process is continued for a time necessary to form a fluorinated film of a desired thickness. Then, the supply of the gases from the
first gas cylinder 23 and thesecond gas cylinder 25 is stopped, and the object S is carried into theprocessing chamber 2. Subsequently, the gas containing at least oxygen atoms is supplied through thebranch pipe 21, thegas supply pipe 18 and thegas passage 19 of the sealingmember 11 into thequartz pipe 10. At the same time, the gas containing at least fluorine atoms is supplied from thefirst gas cylinder 23. The firstflow regulating valve 22 and the secondflow regulating valve 24 are adjusted so that the gas containing at least fluorine atoms and the gas containing at least oxygen atoms are supplied at flow rates and flow rate ratios suitable for etching the object S. - Microwaves generated by the
microwave generator 27 are guided by thewaveguide 12 of theplasma producing device 13 into theplasma producing chamber 14. Consequently, glow discharge is generated in theplasma producing chamber 14 and a plasma P is produced, whereby oxygen contained in the process gas, i.e., a mixed gas of the gas containing at least oxygen atoms and the gas containing at least fluorine atoms, is excited and oxygen radicals are produced. - The process gas containing oxygen radicals is supplied through the
quartz pipe 10, thegas supply pipe 9 and the gas inlet opening 8 into thegas storage chamber 15. Then, the process gas is jetted from thegas storage chamber 15 through the gas jetting holes 17 so as to be uniformly distributed in theprocessing chamber 2 by pressure difference between thegas storage chamber 15 and theprocessing chamber 2. oxygen radicals thus supplied into theprocessing chamber 2 reacts with a thin film formed on a surface of the object S to etch the thin film by an etching process. The process gas reacted with the thin film formed on the surface of the object S is discharged through thegas outlet openings 5 and thedischarge pipes 6 by the vacuum pump. - The oxygen radicals supplied into the
processing chamber 2 reach, for example, theperipheral surface 33 of the layer of theorganic adhesive 32, i.e., a surface of an organic component exposed to the atmosphere of theprocessing chamber 2. However, the etching of theperipheral surface 33 of the layer of theorganic adhesive 32 and the like by the oxygen radicals is limited to the least unavoidable extent and are etched very little because theperipheral surface 33 of the layer of theorganic adhesive 32 and the like are fluorinated beforehand. - The etching process stopped after successively etching several or several tens of objects S, and the fluorinating process is performed after removing the last object S from the object support table3 to fluorinate the surfaces of the organic components again. Then, the etching process is resumed. Thus, the fluorinating process and the etching process are repeated alternately to process several or several tens of objects S successively after fluorinating the surfaces of the organic components.
- Although the embodiment has been described as applied to the etching process for etching objects, the embodiment is applicable also to an ashing process.
- Preferably, the fluorinating gas is one of CF4, C2F6, C3F8, NF3 and SF6, or a mixture of some of these gases.
- Preferably, the process gas is a gas containing at least O2 gas.
- Although the
electrostatic chuck 28 of the vacuum processing apparatus in the foregoing embodiment is covered with theprotective sheet 31, the present invention may be embodied by a vacuum processing method and an apparatus provided with theelectrostatic chuck 28 not covered with any sheet corresponding to theprotective sheet 31. - When the object support table3 as shown in FIG. 6 is employed, the surface of the
electrode covering sheet 30 formed of an polyimide and the exposed surface of the layer of theorganic adhesive 32 are fluorinated by a fluorinating process similar to that described above before an object S is mounted on the object support table 3. - Thus, the etching of the
electrode covering sheet 30 and the surface of the layer of theorganic adhesive 32 with oxygen radicals can be prevented in the etching process for etching the object S with oxygen radicals. - FIG. 3 shows the results of comparative experiments conducted by using the CDE system shown in FIG. 1 to demonstrate the protective effect of the fluorinating process on protecting organic components. Wafers provided with a carbon film, i.e., an organic film, was used as samples. Although the experiments demonstrate the effect of the fluorinating process on the organic films formed on the surfaces of the wafers, the effect holds true for the organic components of the walls of the
vacuum vessel 1 and the object support table 3, such as the layer of the organic adhesive and the sheet of a polyimide. - In FIG. 3, the result of experiments in which the fluorinating process was omitted and the sample wafer was subjected to an etching process for 60 min is shown in an upper section. The etching process used an etching gas containing one part CF4 gas and three parts O2 gas and microwaves of 450 W in power. The
processing chamber 2 was evacuated at 40 Pa and the object support table 3 was kept at 5° C. The carbon film was etched by a depth of 3.9 μm. - The result of experiments in which the sample wafer was subjected to the fluorinating process and the same etching process of the foregoing conditions is shown in a lower section in FIG. 3. The fluorinating process used a mixed gas containing three parts CF4 gas and one part O2 gas. The etching process used an etching gas containing one part CF4 gas and three parts O2 gas and microwaves of 700 W in power. The processing chamber was evacuated at 40 Pa and the object support table 3 was kept at 5° C. for the fluorinating process. After the fluorinating process, the sample wafer was subjected to the etching process.
- The carbon film was etched by a depth of only 0.5 μm, which proved the great effect of fluorination on the suppression of etching of the carbon film by oxygen radicals.
- FIG. 4 is a graph showing etching rate, and O/F radical ratio determined by emission spectral analysis when a film of an organic material was etched with a mixed gas containing CF4 and O2 In FIG. 4, 02/(0 2+CF4) flow rate ratio, i.e., the ratio of the flow rate of O2 gas to the flow rate of the mixed gas (0 2+CF4), is measured on the horizontal axis.
- As obvious from FIG. 4, the O/F radical ratio, i.e., the ratio of the amount of oxygen radicals to that of fluorine radicals produced, and etch rate at which the organic film is etched is increasing along with the increase of O2/(0 2+CF4) flow rate ratio. When the O2 /(O2+CF4) flow rate ratio is about 25% (CF4 gas:O2 gas=3:1), the organic film is etched at a negligibly small etch rate. Therefore, when the fluorinating process is carried out according to such conditions, etching of organic components causes problems scarcely.
- FIG. 5 is a graph showing the dependence of fluorinating rate on O2/(O2+CF4) flow rate ratio, i.e., the ratio of flow rate of O2 gas to that of the mixed gas containing O2 gas and CF4 gas, when an organic film is fluorinated with the mixed gas containing CF4 and O2 by the CDE system shown in FIG. 1. As obvious from FIG. 5, the organic film is scarcely fluorinated when the O2/(O2+CF4) flow rate ratio is greater than 40%.
- When the mixed gas containing CF4 and O2 is used as a fluorinating gas, a preferable O2/(O2+CF4) flow rate ratio is not greater than 40%.
- As is apparent from the foregoing description, the vacuum processing method and the apparatus for carrying the same embodying the present invention fluorinate the surfaces of the organic components exposed to the atmosphere in the
processing chamber 2 with fluorine radicals in the fluorinating process, and then etches the object S with oxygen radicals in the etching process. Therefore, etching of the organic components with oxygen radicals can be prevented. - Since the
electrostatic chuck 28 is covered with and protected by theprotective sheet 31 of a fluororesin, etching of theelectrode covering sheets 30 of theelectrostatic chuck 28 with oxygen radicals can be prevented. - Since the fluorinating process for fluorinating the organic components can be achieved by the vacuum processing apparatus, any special apparatus for the fluorination of the organic components is unnecessary, and the members requiring fluorination by the fluorinating process need not be removed from the vacuum processing apparatus.
- The present invention is not limited in its practical application to the foregoing CDE method and the CDE system, and is applicable to various vacuum processing methods and vacuum processing apparatus which process objects in a vacuum atmosphere. More concretely, the present invention is applicable to dry etching methods and apparatus for carrying out the same, such as reactive ion etching (RIE) methods and apparatus for carrying out the same and microwave plasma etching methods and apparatus for carrying out the same, or ashing methods and apparatus for carrying out the same.
- The present invention can be applied to an etching/ashing process for etching/ashing semiconductor wafers for fabricating ICs and glass substrates for liquid crystal displays.
Claims (18)
1. A vacuum processing method of processing an object to be processed with an oxygen radical in a processing chamber defined by a vacuum vessel of a vacuum processing apparatus, which comprises the steps of:
fluorinating a surface of a component formed of an organic material and exposed to an atmosphere in the processing chamber with a fluorine radical produced by activating a fluorinating gas containing at least a fluorine atom with the vacuum processing apparatus before carrying the object into the processing chamber;
carrying the object into the processing chamber; and
processing the object with the oxygen radical produced by activating a process gas containing at least an oxygen atom.
2. The vacuum processing method according to claim 1 , wherein the vacuum processing apparatus comprises an object support table disposed in the processing chamber to support the object thereon, and an electrostatic chuck mounted on a surface of the object support table to hold the object on the object support table;
the electrostatic chuck comprises an electrode, and an electrode covering sheet covering the electrode; and
the organic material includes both a material forming the electrode covering sheet and an organic adhesive bonding the electrostatic chuck to the surface of the object support table.
3. The vacuum processing method according to claim 1 , wherein the vacuum processing apparatus comprises an object support table disposed in the processing chamber to support the object thereon, an electrostatic chuck mounted on a surface of the object support table to hold the object on the object support table, and a protective sheet of a fluororesin covering the electrostatic chuck to protect the electrostatic chuck;
the organic material includes an organic adhesive used to bond the protective sheet.
4. The vacuum processing method according to any one of claims 1 to 3 , wherein the fluorinating gas is a mixed gas including a gas containing at least a fluorine atom and an O2 gas.
5. The vacuum processing method according to claim 4 , wherein the gas containing at least a fluorine atom is one of CF4 , C2F6, C3F8, NF3 and SF6, or a mixture of some of these gases.
6. The vacuum processing method according to claim 4 or 5, wherein a ratio of a flow rate of the O2 gas to a flow rate of the fluorinating gas including the O2 gas is 40% or below.
7. The vacuum processing method according to any one of claims 1 to 6 , wherein the process gas contains at least an O2 gas.
8. The vacuum processing method according to any one of claims 1 to 7 , wherein the process gas and the fluorinating gas are activated in a plasma producing chamber separated from the processing chamber, and the fluorine radical or the oxygen radical is supplied into the processing chamber.
9. The vacuum processing method according to any one of claims 1 to 8 , wherein the object processing step processes a plurality of objects successively, and the fluorinating step is performed after the object processing step, and the object processing step and the fluorinating step are repeated alternately.
10. A vacuum processing apparatus comprising:
a vacuum vessel defining a processing chamber to be evacuated;
radical producing means for producing a fluorine radical by activating a fluorinating gas including at least a fluorine atom and for producing an oxygen radical by activating a process gas containing at least an oxygen atom;
gas supply means for supplying the fluorinating gas or the process gas to the radical producing means; and
an object support table disposed in the processing chamber to support an object to be processed thereon;
wherein a surface of a component formed of an organic material and exposed to an atmosphere in the processing chamber is fluorinated by the fluorine radical, and then the object is mounted on the object support table and processed with the oxygen radical.
11. A vacuum processing apparatus comprising:
a vacuum vessel defining a processing chamber to be evacuated;
radical producing means for producing an oxygen radical by activating a process gas containing at least an oxygen atom;
gas supply means for supplying the process gas to the radical producing means;
an object support table disposed in the processing chamber to support an object to be processed thereon;
an electrostatic chuck mounted on a surface of the object support table to hold the object on the object support table; and
a protective sheet formed of a fluororesin and covering the electrostatic chuck to protect the electrostatic chuck.
12. The vacuum processing apparatus according to claim 10 or 11, wherein a surface of a component formed of an organic material and exposed to an atmosphere in the processing chamber is fluorinated with a fluorine radical produced by activating a fluorinating gas containing at least a fluorine atom with the radical producing means.
13. The vacuum processing apparatus according to claim 12 , wherein the fluorinating gas is a mixed gas including a gas containing at least a fluorine atom and an O2 gas.
14. The vacuum processing apparatus according to claim 13 , wherein the gas containing at least a fluorine atom is one of CF4, C2F6, C3F8, NF3 and SF6, or a mixture of some of these gases.
15. The vacuum processing apparatus according to claim 13 or 14, wherein a ratio of a flow rate of the O2 gas to a flow rate of the fluorinating gas including the O2 gas is 40% or below.
16. The vacuum processing apparatus according to any one of claims 10 to 15 , wherein the process gas contains at least an O2 gas.
17. The vacuum processing apparatus according to any one of claims 10 to 16 , wherein the radical producing means has a plasma producing chamber separated from the processing chamber, and the radical produced in the plasma producing chamber is supplied into the processing chamber.
18. The vacuum processing apparatus according to any one of claims 10 to 17 , wherein a cycle of fluorinating a component formed of an organic material and exposed to an atmosphere in the processing chamber and successively processing a plurality of objects is repeated.
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US10/152,001 US20020134753A1 (en) | 1997-04-28 | 2002-05-22 | Vacuum processing method and vacuum processing apparatus |
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JPH0864581A (en) | 1994-08-25 | 1996-03-08 | Sumitomo Metal Ind Ltd | Plasma ashing device |
JPH0982787A (en) * | 1995-09-19 | 1997-03-28 | Toshiba Corp | Plasma treating apparatus and method |
JP2956571B2 (en) * | 1996-03-07 | 1999-10-04 | 日本電気株式会社 | Semiconductor device |
-
1998
- 1998-04-28 JP JP54682898A patent/JP3394263B2/en not_active Expired - Fee Related
- 1998-04-28 TW TW087106552A patent/TW411491B/en not_active IP Right Cessation
- 1998-04-28 DE DE69826120T patent/DE69826120T2/en not_active Expired - Fee Related
- 1998-04-28 CN CNB988065010A patent/CN1149646C/en not_active Expired - Fee Related
- 1998-04-28 KR KR1019997009949A patent/KR100319662B1/en not_active IP Right Cessation
- 1998-04-28 EP EP98917717A patent/EP0980092B1/en not_active Expired - Lifetime
- 1998-04-28 WO PCT/JP1998/001949 patent/WO1998049720A1/en active IP Right Grant
-
1999
- 1999-10-28 US US09/429,558 patent/US6465363B1/en not_active Expired - Fee Related
-
2002
- 2002-05-22 US US10/152,001 patent/US20020134753A1/en not_active Abandoned
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060096709A1 (en) * | 2002-02-05 | 2006-05-11 | Lee Sang S | LCD bonding machine and method for fabricating LCD by using the same |
US7647959B2 (en) * | 2002-02-05 | 2010-01-19 | Lg Display Co., Ltd. | LCD bonding machine and method for fabricating LCD by using the same |
US20080185364A1 (en) * | 2007-02-06 | 2008-08-07 | Tokyo Electron Limited | Plasma etching method, plasma etching apparatus, control program and computer-readable storage medium |
US8216485B2 (en) * | 2007-02-06 | 2012-07-10 | Tokyo Electron Limited | Plasma etching method, plasma etching apparatus, control program and computer-readable storage medium |
Also Published As
Publication number | Publication date |
---|---|
EP0980092A4 (en) | 2000-03-29 |
WO1998049720A1 (en) | 1998-11-05 |
KR100319662B1 (en) | 2002-01-16 |
KR20010020335A (en) | 2001-03-15 |
JP3394263B2 (en) | 2003-04-07 |
DE69826120D1 (en) | 2004-10-14 |
TW411491B (en) | 2000-11-11 |
US6465363B1 (en) | 2002-10-15 |
EP0980092B1 (en) | 2004-09-08 |
CN1261460A (en) | 2000-07-26 |
CN1149646C (en) | 2004-05-12 |
EP0980092A1 (en) | 2000-02-16 |
DE69826120T2 (en) | 2005-09-22 |
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STCB | Information on status: application discontinuation |
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