Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
  • C23C16/44—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating
  • C23C16/455—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the method of coating characterised by the method used for introducing gases into reaction chamber or for modifying gas flows in reaction chamber
  • C23C16/45563—Gas nozzles
  • C23C16/45568—Porous nozzles
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/32431—Constructional details of the reactor
  • H01J37/3244—Gas supply means
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
  • H01J37/32—Gas-filled discharge tubes
  • H01J37/32431—Constructional details of the reactor
  • H01J37/32532—Electrodes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10P—GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
  • H10P50/00—Etching of wafers, substrates or parts of devices
  • H10P50/20—Dry etching; Plasma etching; Reactive-ion etching
  • H10P50/24—Dry etching; Plasma etching; Reactive-ion etching of semiconductor materials
  • H10P50/242—Dry etching; Plasma etching; Reactive-ion etching of semiconductor materials of Group IV materials

Definitions

• the present invention relates to an electrode member for a plasma treating apparatus to be attached to the front surface of the gas supplying port of an electrode for plasma generation in the plasma treating apparatus. Further, the present invention relates to a plasma treating apparatus and plasma treating method using the above-mentioned electrode member.
• a plasma treating apparatus serves to generate plasma under a vacuum atmosphere and to carry out a treatment such as etching over the surface of anobject tobe treatedphysicallyandchemicallybytheplasma.
• the plasma is generated by applying a high frequency voltage to an electrode in a sealed treatment chamber.
• a gas for plasma generation having a predetermined pressure (hereinafter referred to as a "gas") is supplied in the treatment chamber.
• a high density plasma should be generated depending on the purposes of the treatment.
• a plasma treating apparatus for carrying out plasma etching on a silicon substrate such as a semiconductor wafer
• a method of spraying and supplying a gas having a comparativelyhighpressure onto the surface of a silicon wafer is used in order to enhance the treatment efficiency.
• a conventional method in which a gas supplying port is formed on an upper electrode provided opposite to a lower electrode holding a silicon wafer.
• the upper electrode serves as a discharge electrode plate and a gas introducing plate.
• the discharge electrode plate has a large number of fine gas supplying holes and is attached to the upper electrode, thereby uniformly supplying a gas to the surface of a silicon wafer.
• an abnormal discharge in which plasma is convergently generated in the vicinity of the supplying hole is apt to be induced and various drawbacks are caused by the abnormal discharge. More specifically, etching is convergently carried out in a portion in which the abnormal discharge is generated. Therefore, there is a drawback in that the quality of etching is affected, for example, a silicon wafer is damaged or an etching result has a variation. In addition, there is a drawback that a discharge electrode plate provided with the gas supplyinghole is wornbytheplasma, dependingonthematerial of the discharge electrode plate.
• porous ceramic having crystal grains, having a diameter of about lO ⁇ m to 50 ⁇ m, aggregated and sintered has been tried to be used as a discharge electrode plate.
• the discharge electrode plate is easily broken due to heat shock causedby the heat ofplasma, it cannot be usedas a discharge electrode to be directly exposed to the plasma.
• a first aspect of the invention is directed to an electrode member for a plasma treating apparatus which includes a plasma generation electrode having the gas supplyingport for supplying a gas for plasma generation to a treatment chamber, the electrode member to be attached to a front surface of the gas supplying port, wherein the electrode member having a three-dimensional network structure and a clearance of the three-dimensional network structure constituting a plurality of irregular paths for causing the gas for plasma generation supplied from the gas supplying port to pass therethrough, a size of the clearance is set in a range from lOO ⁇ m to 300.
• a plasma treating apparatus comprises: a treatment chamber; a first electrode having a holding portion for holding a work in the treatment chamber; a second electrode provided in a position opposed to the first electrode and having a gas supplying port for supplying a gas for plasma generation to the treatment chamber; a pressure control portion for reducing a pressure in the treatment chamber; a gas supplying portion for supplying the gas for plasma generation to the treatment chamber through the gas supplying port; a high frequency generating portion for applying a high frequency voltage between the first electrode and the second electrode; and an electrode member to be attached to a front surface of the gas supplyingport, whereinthe electrode member has a three-dimensional network structure and a clearance of the three-dimensional network structure constitutes a plurality of irregular paths for causing the gas for plasma generation to pass therethrough.
• a plasma treating method in a plasma treating apparatus comprising a treatment chamber, a first electrode having a holding portion for holding a work in the treatment chamber, a second electrode provided in a position opposed to the first electrode and having a gas supplying port for supplying a gas for plasma generation to the treatment chamber, apressure control portion for reducing a pressure in the treatment chamber, a gas supplying portion for supplying the gas for plasma generation to the treatment chamber through the gas supplying port, a high frequency generatingportion for applying a high frequency voltage between the first electrode and the second electrode, and an electrode member to be attached to a front surface of the gas supplying port, wherein the electrode member has a three-dimensional network structure, the method comprises the steps of: stacking a protective tape to a surface, on which a circuit pattern is formed, of a semiconductorwafer; holdingthe semiconductorwafer on the holding portion such that a back surface of the semiconductor wafer being upward; applying a high frequency voltage between the first electrode and the second electrode while spraying
• the electrode member having the three-dimensional network structure of which clearance constitutes a plurality of irregular paths for causing the gas for plasma generation to pass therethrough is used as the electrode member to be attached to the front surface of the gas supplying port of the electrode for plasma generation. Consequently, the gas to be supplied by the rectifying function of the irregular paths can be distributed uniformly to prevent an abnormal discharge, thereby carrying out uniform etching having no variation.
• the rectifying function means that the gas supplied and passed in the irregular paths are made uniform in its injectionpressure entire surface of the electrodemember, while the injection directions in the irregular paths are influenced to be an even flow entire surface of the electrode member.
• the three-dimensional network structure is provided so that a sufficient durability can be obtained also in a place to be exposed directly by plasma, that is, a place to be exposed by a great thermal shock.
• Fig. 1 is a sectional view showing a plasma treating apparatus according to an embodiment of the invention
• Fig. 2A is a sectional view showing an electrode member according to the embodiment of the invention.
• Fig.2B is an enlarged sectional view showing the electrode member of Fig. 2A;
• Fig. 3 is a flow chart for manufacturing the electrode member according to the embodiment of the invention
• Fig. 4 is a view illustrating a method of manufacturing the electrode member according to the embodiment of the invention.
• Fig. 5 is a view showing the gas flow distribution of the plasma treating apparatus according to the embodiment of the invention.
• a treatment chamber 2 for carrying out a plasma treatment.
• a lower electrode 3 (a first electrode) and an upper electrode 4 (a second electrode) are vertically opposed to each other in the treatment chamber 2.
• the lower electrode 3 includes an electrode body 5 attached to the vacuum chamber 1 through an insulator 9 made of polytetrafluoroethylene by a support portion 5a extended downward.
• the vacuum chamber 1 and the electrode body 5 are formed of aluminum, stainless steel, or other suitable material.
• the holding portion 6 is formed witha ceramic coating on a surface of aluminum, stainless steel, or other suitable material.
• the silicon wafer 7 is set in a state obtained immediately after the back side of a circuit pattern formation surface is thinned by mechanical polishing or grinding, and a damage layer including a micro-crack is formed on a polished surface.
• a protective tape 7a (see Fig. 5) is stuck to the circuit pattern formation surface of the silicon wafer 7 and is placed in contact with the holding portion 6.
• the polished surface (the back side of the circuit formation surface) to be treated is turned upward.
• the damaged layer of the polished surface is removed (etched) by the plasma treatment.
• Alarge number of suctionholes 6a openedto anupper surface are provided in the holding portion 6, and communicate with a sucking path 5d extending through the support portion 5a of the electrode body 5.
• the sucking path 5d is connected to a vacuum sucking portion 11 and vacuum suction is carried out through the vacuum sucking portion 11 with the silicon wafer 7 mounted on the upper surface of the holding portion 6 so that the silicon wafer 7 is held in the holding portion 6 by vacuum sucking.
• Refrigerant passages 6b and ⁇ c for cooling are provided in the holding portion 6 and communicate with ducts 5b and 5c extending through the support portion 5a.
• the ducts 5b and 5c are connected to a refrigerant circulating portion 10.
• a refrigerant such as cooling water is circulated in the refrigerant passages 6b and 6c. Consequently, the holding portion 6 heated by heat generated during the plasma treatment is cooled.
• the electrode body 5 is electrically connected to a high frequencygeneratingportion 12 andthehigh frequencygenerating portion 12 applies a high frequency voltage between the lower electrode 3 and the upper electrode 4.
• the treatment chamber 2 in the vacuum chamber 1 is connected to a pressure control portion 13.
• the pressure control portion 13 carries out a pressure reduction in the treatment chamber 2 and atmospheric opening at a vacuum breakdown in the treatment chamber 2.
• the upper electrode 4 is provided in an opposite position to the lower electrode 3 and includes an electrode body 15, which is made of aluminum , stainless steel or other suitable material, grounded to a grounding portion 20.
• the electrode body 15 is attached to the vacuum chamber 1 through an insulator 16 made ofpolytetrafluorethyleneby a support 15a extendedupward.
• the electrode body 15 is an electrode for plasma generation and for supplying a gas for plasma generation to the treatment chamber 2, and has a lower surface provided with a gas supplying port 15b communicatingwith a gas supplyingpath 15c extending through the support portion 15a.
• the gas supplying path 15c is connected to a gas supplying portion 19 that supplies, as the gas for plasma generation, a gas mixture containing a fluorine-based gas, such as carbon tetrafluoride (CF 4 ) or sulfur hexafluoride (SF 6 ) .
• a fluorine-based gas such as carbon tetrafluoride (CF 4 ) or sulfur hexafluoride (SF 6 ) .
• the electrode member 17 is attached to the front surface of the gas supplying port 15b.
• the electrode member 17 is a disc-shaped member comprising a ceramic porous substance.
• the ceramic porous substance has a three-dimensional network structure in which a frame portion 18a of ceramic is formed continuously as a three-dimensional network and has a large number of hole portions 18b (clearances) therein.
• An average size of the hole portions 18b is about lOO ⁇ m
• the three-dimensional network structure constitutes a plurality of irregular paths to allow a gas to pass through the electrode member 17 from the gas supplying port 15b .
• the electrode member 17 has a thickness greater than 5mm.
• the electrode member 17 is manufactured by sticking ceramic to a polyurethane foamto be abase material .
• a plate-shapedurethane foam 22 is prepared (ST1), and is cut to take a predetermined shape of a disc to fabricate a base material 23 as shown in Fig.
• the urethane foam 22 has such a structure that a core
• alumina powder to be a ceramic material is prepared (ST3) and water and a surfactant for applying a fluidity to the alumina powder is added thereto, thereby forming a slurry solution 24 (ST4) .
• the base material 23 is immersed in the slurry 24 (ST5) and an excess slurry is removed from the base material 23 after pull-up (ST6) . Thereafter, the base material 23 is dried to remove the water content (ST7) . Subsequently, heating is carried out to cure the ceramic so that an electrode member comprising the ceramic porous substance havingthe three-dimensional network structure is finished (ST8) .
• the base material 23 disappears as burnt urethane in the heating step. Therefore, an electrode member containing only the ceramic material is obtained.
• the steps (ST5) to (ST7) are repeatedly carried out plural times if necessary.
• the electrodemember 17 thus anufacturedhas the following characteristics.
• the frame portion 18a forming theholeportion 18b ismoldedbysticking ceramic to theperiphery of the core 22a of the urethane foam22. Therefore, itispossible to obtain a porous substance having a uniform pore size and distribution of the hole portion 18b.
• a mean pore size is preferably 800 ⁇ m or less in order to prevent the concentration of aplasma (an abnormal discharge) . Morepreferably, an average of the pore size is set as lOO ⁇ m to 300 ⁇ m.
• a porosity is mainly determined by the array density of the core 22a in the urethane foam22 tobeusedas abasematerial . Accordingly, itispossible to stick ceramic having fine crystal grains to the periphery of the core 22a and to sinter the ceramic at a high temperature, thereby forming the frame portion 18a constituted by a fine ceramic sintered substance having a high strength, a heat resistance and a heat shock resistace.
• Grain size of ceramic powder used in the invention is about 0.5 ⁇ m to 2.0 ⁇ m.
• the electrode member 17 comprising a ceramic porous substance thus manufactured is formedby continuouslyproviding, like the three-dimensional network, the frame portion 18a having such a structure that the fine crystal of alumina is bonded at a high density. Therefore, a heat resistance and a heat shock resistance are excellent. More specifically, even if the electrode member 17 is used in a severe place to be directly exposed to a plasma in the plasma treating apparatus, the frame portion 18a having the mutual crystal grains bonded strongly is continuously formed with a three-dimensionally isotropic structure. Therefore, a crack or a breakdown is not generated by a thermal shock. Accordingly, a sufficient durability can be obtained also in a place to be directly exposed to the plasma.
• the electrode member 17 can be formed to have a desirable shape very easily by previously cutting the urethane foam 22 into a predetermined shape .
• the plasma treating apparatus is constituted as described above, and the plasma treatment (etching) to be carried out for the silicon wafer 7 will be described below with reference to Fig. 5.
• the silicon wafer 7 is mounted on the holding portion 6 with the protective tape 7a turned downward.
• a pressure reduction is carried out in the treatment chamber 2 bythepressure controlportion 13 (Fig.1) , andthe gas supplying portion 19 is then driven. Therefore, a gas is in ecteddownward from the electrode member 17 attached to the upper electrode 4.
• the gas supplied from the gas supplying portion 19 can be prevented from freely flowing in the gas supplying port 15b by means of the electrode member 17. Consequently, the gas temporarily stays in the gas supplying port 15b so that a distribution in the pressure of the gas becomes almost uniform therein.
• the gas reaches the lower surface of the electrode member 17 from the gas supplying port 15b through the hole portions 18b (Fig. 2) of the ceramic porous substance constituting the electrode member 17 and is sprayed toward the surface of the silicon wafer 7 which is provided thereunder.
• a large number of hole portions 18b are formed in an irregular arrangement in the electrode member 17. Therefore, the distribution of the flow of the gas to be sprayed downward from the lower surface of the electrodemember 17 becomes uniform without a deviation over almost the whole range of the gas supplying port 15b.
• the high frequency generating portion 12 is driven to apply a high frequency voltage to the electrode body 5 of the lower electrode 3. Consequently, aplasmadischarge is generated in a space formed between the upper electrode 4 and the lower electrode 3.
• Aplasma etching treatment is carried out over the upper surface of the silicon wafer 7 mounted on the holding portion 6 through the plasma generated by the plasma discharge.
• an etching rate of 2 ⁇ m/min canbe obtained. According to the present invention, an etching rate higher than l ⁇ m/min is obtained.
• the distribution of the flow of the gas to be sprayed onto the surface of the silicon wafer 7 is made uniform over the whole range by means of the electrode member 17 having a rectifying function. Therefore, it is possible to prevent an abnormal discharge from being generated due to the concentration of the plasma discharge over such a range that the gas partially has a high density.
• the electrode member 17 according to the embodiment includes the frame portion 18a having mutual crystal grains bonded strongly which is continuously provided with the three-dimensionallyisotropic structure (the three-dimensional network structure) . Even if the electrode member 17 is used in a severe place to be directly exposed to plasma, a crack or a breakdown is not generated by thermal shock. Accordingly, if a rectifying plate for making the distribution of the gas flow uniform is to be provided in the gas supplying port, it is conventionally necessary to provide the rectifying plate separately from the discharge electrode plate to be exposed to the plasma. In the embodiment, however, the same electrode member 17 can functionas the discharge electrode plate and the rectifying plate.
• the alumina has been taken as an example of the material of the electrode member 17
• borosilicate glass which is an alkaline rare earth metal, also canbe used as a material of the electrode member .
• metal fluoride having a high boiling point and a low vapor pressure in vacuum which is represented by oxide, nitride and carbide containing alkaline earthmetal in addition to the alumina based gas .
• the three-dimensional network structure (the three-dimensional network structure) of a fabric, a linear fiber or metal may be used in place of the urethane foam 22.
• the electrode member 17 having the three-dimensional network structure it is also possible to use a method of mixing and sintering fine particles of ceramic and beads-shaped resin particles .
• the resin particles are burnt by heat during the sintering, and a space formed by the burning becomes an irregular path and a residual structure becomes the frame portion 18a constituting the three-dimensional network structure.
• the silicon wafer 7 for the semiconductor device to be a silicon based substrate is intended for the plasma treatment
• the invention is not restricted to the silicon wafer 7.
• a quartz plate to be used for a quartz oscillator which is intended for a material containing silicon can also be applied to the invention.
• the electrode member having the three-dimensional network structure of which clearance constitutes the irregular paths for causing a gas for plasma generation to pass therethrough is used as the electrode member to be attached to the front surface of the gas supplying port of the electrode for plasma generation. Consequently, the distribution of the gas to be supplied can be made uniform to prevent an abnormal discharge and uniform etching having no variation canbe carried out. Moreover, the three-dimensional network structure can produce a sufficient durability even in a place to be directly exposed to the plasma.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• Physics & Mathematics (AREA)
• Analytical Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Drying Of Semiconductors (AREA)
• Plasma Technology (AREA)
• ing And Chemical Polishing (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)

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• 2001
  • 2001-06-25 JP JP2001190891A patent/JP2003007682A/ja active Pending
• 2002
  • 2002-06-21 US US10/176,804 patent/US7138034B2/en not_active Expired - Fee Related
  • 2002-06-24 WO PCT/JP2002/006293 patent/WO2003001557A1/en not_active Ceased
  • 2002-06-24 KR KR1020037016901A patent/KR100845178B1/ko not_active Expired - Fee Related
  • 2002-06-24 CN CNB02812684XA patent/CN1302512C/zh not_active Expired - Fee Related
  • 2002-06-24 DE DE10296978T patent/DE10296978B4/de not_active Expired - Fee Related
  • 2002-06-25 MY MYPI20022358A patent/MY142898A/en unknown
  • 2002-06-25 TW TW091113856A patent/TW559942B/zh not_active IP Right Cessation

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