Pulsed sputtering with a small rotating magnetron
AssigneeApplied Materials, Inc.
InventorsWei Wang, Praburam Gopalraja, Jianming Fu, Zheng Xu
Life of this patent
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Abstract
A magnetron sputter reactor having a target that is pulsed with a duty cycle of less than 10% and preferably less than 1% and further having a small magnetron of area less than 20% of the target area rotating about the target center, whereby a very high plasma density is produced during the pulse adjacent to the area of the magnetron. The power pulsing frequency needs to be desynchronized from the rotation frequency so that the magnetron does not overlie the same area of the magnetron during different pulses. Advantageously, the power pulses are delivered above a DC background level sufficient to continue to excite the plasma so that no ignition is required for each pulse.
Claims27
A pulsed magnetron sputter reactor, comprising:
- a plasma sputter reactor having a target and a pedestal for supporting a substrate to be sputter deposited in opposition to said target;
- a magnetron having an area of less than 20% of the area of the target and being rotatable about a back of said target;
- and
- a power supply connected to said target and delivering pulses of power of negative voltage with a duty cycle of less than 10%.
A pulsed magnetron sputter reactor, comprising:
- a plasma sputter reactor having a target and a pedestal for supporting a substrate to be sputter deposited in opposition to said target;
- a magnetron having an area of less than 20% of the area of the target and being rotatable about a back of said target;
- and
- a power supply connected to said target and delivering pulses of power with a duty cycle of less than 10%;
- wherein said power supply delivers said pulses braving a peak power level rising from a background power level, whereby power delivered from said power supply does not fill below a finite level between said pulses, whereby a plasma is continuously maintained in said reactor between said pulses.
A pulsed magnetron sputter reactor, comprising:
- a plasma sputter reactor having a target and a pedestal for supporting a substrate to be sputter deposited in opposition to said target;
- a magnetron positioned at a back of said target;
- an adjustable DC power supply connected to said target delivering a selected negative DC voltage;
- a pulsed power supply connected in parallel with said adjustable DC power supply and delivering pulses of negative voltage with a duty cycle of less than 10%;
- and
- a motor for rotating said magnetron at a rotation frequency and wherein said power supply delivers said pulses at a repetition frequency, wherein said rotation frequency is desynchronized from said repetition frequency such that said pulses are delivered at respective times at which said magnetron is respectively positioned at at least ten different angular positions at said back of said target.
A pulsed magnetron sputter reactor, comprising:
- a plasma sputter reactor having a target and a pedestal for supporting a substrate to be sputter deposited in opposition to said target;
- a magnetron positioned at a back of said target;
- an adjustable DC power supply connected to said target delivering a selected negative DC voltage;
- and
- a pulsed power supply connected in parallel with said adjustable DC power supply and delivering pulses of negative voltage with a duty cycle of less than 10%.
A pulsed magnetron sputter reactor, comprising:
- a plasma sputter reactor having a target and a pedestal for supporting a substrate to be sputter deposited in opposition to said target;
- a magnetron positioned at a back of said target;
- an adjustable DC power supply connected to said target delivering a selected negative DC voltage;
- and
- a pulsed power supply connected in parallel with said adjustable DC power supply and delivering pulses of negative voltage with a duty cycle of less than 1%.
A pulsed magnetron sputter reactor, comprising:
- a plasma sputter reactor having a target and a pedestal for supporting a substrate to be sputter deposited in opposition to said target;
- a magnetron positioned at a back of said target;
- an adjustable DC power supply connected to said target delivering a selected negative DC voltage;
- and
- a pulsed power supply connected in parallel with said adjustable DC power supply and delivering pulses of negative voltage with a duty cycle of less than 10%;
- wherein said adjustable DC power supply is effective at igniting and maintaining a plasma in said plasma sputter reactor without use of said pulsed power supply.
A pulsed magnetron sputter reactor, comprising:
- a plasma sputter reactor having a target and a pedestal for supporting a substrate to be sputter deposited in opposition to said target;
- a magnetron positioned at a back of said target, wherein said magnetron is rotatable about a central axis of said target and has an area of no more than 20% of that of said target;
- an adjustable DC power supply connected to said target delivering a selected negative DC voltage;
- and
- a pulsed power supply connected in parallel with said adjustable DC power supply and delivering pulses of negative voltage with a duty cycle of less than 10%.
A method of operating a sputter reactor, comprising the steps of:
- rotating a magnetron about the back of a target of the reactor, said back being on an opposite side of said target than a front thereof facing a substrate to be sputter coated, said magnetron having an area of no more than 20% of an area of said target;
- and
- applying pulses of power of negative voltage to said target to excite a plasma in said reactor, said pulses having a duty cycle of less than 10%.
A method of operating a sputter reactor, comprising the steps of
- rotating a magnetron about the back of a target of the reactor, said back being on an opposite side of said target than a front thereof facing a substrate to be sputter coated, said magnetron having an area of no more than 20% of an area of said target;
- applying pulses of power to said target to excite a plasma in said reactor, said pulses having a duty cycle of less than 10%;
- and
- applying at least a minimum level of power to said target between said pulses sufficient to maintain said plasma in a chamber of said sputter reactor between said pulses.
A multi-step sputtering process performed in a sputter reactor including a pulsed power supply delivering a sequence of pulses at a duty cycle to a target, said process comprising the steps of:
- a first step of delivering said pulses at a first duty cycle to said target to irradiate a substrate with particles sputtered from said target;
- and
- a second step of delivering said pulses at a second duty cycle different from said first duty to said target to irradiate said substrate with particles sputtered from said target;
- wherein at least one of said duty cycles is less than 10%.
A pulsed magnetron sputter reactor, comprising:
- a plasma sputter reactor having a target and a pedestal for supporting a substrate to be sputter deposited in opposition to said target and an anode with respect to a cathode of said target;
- a magnetron rotatable about a back of said target;
- and
- a power supply connected to said target and delivering pulses to said target of power of negative voltage with respect to said anode and having a duty cycle of less than 10%.
A method of operating a sputter reactor, comprising the steps of:
- rotating a magnetron about the back of a target of the reactor, said back being on an opposite side of said target than a front thereof facing a substrate to be sputter coated, said reactor having an anode with respect to a cathode of said target;
- and
- applying to said target pulses of power of negative power with respect to said anode target to excite a plasma in said reactor, said pulses having a duty cycle of less than 10%.
Dependencies are inferred from the claim text.