Control of particle generation within a reaction chamber
First Claim
1. A method for agitating and/or circulating particles present within a reaction chamber, comprising the steps of:
- increasing the power level of an RF signal supplied to electrodes within the reaction chamber at a first rate of about 500 to 2000 watts/second to initiate a first plasma therein, wherein said RF signal power level is rapidly increased;
exhausting said particles from within said reaction chamber; and
positioning a semiconductor wafer within said reaction chamber for wafer processing;
increasing the power level of an RF signal supplied to electrodes within the reaction chamber at a second rate from about less than 1 watt/second to 100 watts/second to initiate a second plasma therein, wherein said RF signal power level is slowly increased, and wherein said second plasma does not agitate and/or circulate said particles.
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Accused Products
Abstract
An RF signal is rapidly brought to a high power level prior to the introduction of a wafer into the reaction chamber to initiate a plasma that agitates and circulates any particles within the reaction chamber, thereby allowing effective reaction chamber cleaning; and an RF signal is slowly brought to a high power level to initiate a plasma prior to or during wafer processing to avoid disturbing and circulating such particles during wafer processing, thereby preventing particle induced contamination. A magnetic field may be applied to the reaction chamber to move particles from a plasma sheath/glow region interface to a reaction chamber exhaust line, and thereby prevent such particles from falling onto a processed wafer.
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Citations
14 Claims
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1. A method for agitating and/or circulating particles present within a reaction chamber, comprising the steps of:
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increasing the power level of an RF signal supplied to electrodes within the reaction chamber at a first rate of about 500 to 2000 watts/second to initiate a first plasma therein, wherein said RF signal power level is rapidly increased; exhausting said particles from within said reaction chamber; and positioning a semiconductor wafer within said reaction chamber for wafer processing; increasing the power level of an RF signal supplied to electrodes within the reaction chamber at a second rate from about less than 1 watt/second to 100 watts/second to initiate a second plasma therein, wherein said RF signal power level is slowly increased, and wherein said second plasma does not agitate and/or circulate said particles. - View Dependent Claims (2, 3)
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4. A method for removing contaminating particles trapped in a plasma sheath/glow region interface within a reaction chamber, comprising the steps of:
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removing any reactants used during processing from the reaction chamber; maintaining said plasma within the reaction chamber; filling the reaction chamber with an inert gas; applying a magnetic field to said reaction chamber, such that the force and velocity components of said magnetic field are oriented to move said particles away from said plasma sheath/interface; and exhausting said particles from said reaction chamber.
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5. A method for preventing contamination of a semiconductor wafer during integrated circuit fabrication within a reaction chamber, comprising the steps of:
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increasing the power level of an RF signal supplied to electrodes within the reaction chamber at a first selected rate, prior to introduction of said semiconductor wafer into said reaction chamber for processing, to initiate a first plasma therein, said first plasma effecting controlled agitation and/or circulation of said particles within said reaction chamber; exhausting said particles from within said reaction chamber to effect chamber cleaning; extinguishing said first plasma; positioning said semiconductor wafer within said reaction chamber for wafer processing; increasing the power level of an RF signal supplied to electrodes within the reaction chamber at a second selected rate to initiate a second plasma therein;
wherein said second plasma does not agitate and/or circulate said particles. - View Dependent Claims (6, 7, 8)
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9. A method for initiating a plasma within a reaction chamber without agitating and/or circulating particles present therein, comprising the steps of:
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positioning a semiconductor wafer within said reaction chamber for wafer processing; introducing an inert gas into said reaction chamber; slowly increasing the power level of an RF signal supplied to electrodes within the reaction chamber at a rate of about less than 1 watt/second to 100 watts/second to initiate a plasma therein having a shallow ramp; and introducing a reactant into said reaction chamber after said plasma is at full power. - View Dependent Claims (10, 11)
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12. A method for preventing contamination of a semiconductor wafer during integrated circuit fabrication within a reaction chamber, comprising the steps of:
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rapidly increasing the power level of an RF signal supplied to electrodes within the reaction chamber at a rate of about 500 to 2000 watts/second, prior to introduction of said semiconductor wafer into said reaction chamber for processing, to initiate a first plasma therein having a steep ramp;
said plasma effecting controlled agitation and/or circulation of said particles within said reaction chamber;exhausting said particles from within said reaction chamber to effect chamber cleaning; extinguishing said first plasma; positioning said semiconductor wafer within said reaction chamber for wafer processing; slowly increasing the power level of an RF signal supplied to electrodes within the reaction chamber at a rate from less than 1 watt/second to 100 watts/second to initiate a second plasma therein having a shallow ramp;
wherein said second plasma does not agitate and/or circulate said particles;applying a magnetic field generated by a magnet placed proximate to said reaction chamber; removing residual particles from a second plasma sheath/glow region interface in response to said magnetic field; and exhausting said residual particles from said reaction chamber.
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13. An apparatus for preventing contamination of a semiconductor wafer during integrated circuit fabrication within a reaction chamber, comprising:
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a control circuit that generates a drive signal; an RF generator that provides an output RF signal having a ramp rate that is a function of the ramp rate of said drive signal; wherein said drive signal increases the power level of the RF signal supplied by said RF generator to electrodes within the reaction chamber at a first rate of about 500 to 2000 watts/second, prior to introduction of said semiconductor wafer into said reaction chamber for processing, to initiate a first plasma therein, said first plasma effecting controlled agitation and/or circulation of said particles within said reaction chamber; and
at a second rate of about less than 1 watt/second to 100 watts/second, after introduction of said semiconductor wafer into said reaction chamber for processing, to initiate a second plasma therein, wherein said second plasma does not agitate and/or circulate said particles; andan exhaust adapted to remove said particles from within said reaction chamber to effect chamber cleaning prior to introduction of said semiconductor wafer into said reaction chamber for processing. - View Dependent Claims (14)
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Specification