Method and apparatus for depositing films
First Claim
1. An apparatus for performing physical vapor deposition of a layer on a substrate, said apparatus comprising:
- a deposition chamber enclosing a plasma region for containing an ionizable gas;
an electromagnetic field generator surrounding said plasma region for inductively coupling an electromagnetic field into said plasma region to ionize the gas and generate and maintain a high density, low potential plasma;
a source of deposition material including a solid target constituting a source of material to be deposited onto the substrate;
an electrical bias circuit associated with said target adapted to electrically bias said target in order to cause ions in the plasma to strike said target and sputter material from said target; and
a substrate holder for holding the substrate at a location to permit material sputtered from said target to be deposited on the substrate, wherein said electromagnetic field generator comprises;
a source of RF electrical power;
an electrostatic shield surrounding said plasma region, said electrostatic shield is a conductive member having regions that allow passage of RF electromagnetic energy, which regions have a lower bound that is not lower than the location of a substrate held by said substrate holder; and
a coil surrounding said shield and coupled to said source of RF electrical power for converting RF power from said source into the electromagnetic field that is coupled into said plasma region; and
a voltage source adapted to apply a DC bias to said shield.
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Abstract
A method and apparatus for performing physical vapor deposition of a layer or a substrate, composed of a deposition chamber enclosing a plasma region for containing an ionizable gas; an electromagnetic field generating system surrounding the plasma region for inductively coupling an electromagnetic field into the plasma region to ionize the gas and generate and maintain a high density, low potential plasma; a source of deposition material including a solid target constituting a source of material to be deposited onto the substrate; a unit associated with the target for electrically biasing the target in order to cause ions in the plasma to strike the target and sputter material from the target; and a substrate holder for holding the substrate at a location to permit material sputtered from the target to be deposited on the substrate.
58 Citations
28 Claims
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1. An apparatus for performing physical vapor deposition of a layer on a substrate, said apparatus comprising:
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a deposition chamber enclosing a plasma region for containing an ionizable gas;
an electromagnetic field generator surrounding said plasma region for inductively coupling an electromagnetic field into said plasma region to ionize the gas and generate and maintain a high density, low potential plasma;
a source of deposition material including a solid target constituting a source of material to be deposited onto the substrate;
an electrical bias circuit associated with said target adapted to electrically bias said target in order to cause ions in the plasma to strike said target and sputter material from said target; and
a substrate holder for holding the substrate at a location to permit material sputtered from said target to be deposited on the substrate, wherein said electromagnetic field generator comprises;
a source of RF electrical power;
an electrostatic shield surrounding said plasma region, said electrostatic shield is a conductive member having regions that allow passage of RF electromagnetic energy, which regions have a lower bound that is not lower than the location of a substrate held by said substrate holder; and
a coil surrounding said shield and coupled to said source of RF electrical power for converting RF power from said source into the electromagnetic field that is coupled into said plasma region; and
a voltage source adapted to apply a DC bias to said shield. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
a metal plate to which said target is affixed; and
a cooling system thermally coupled to said target for removing heat from said target at a high rate.
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7. The apparatus of claim 6 wherein said first source of RF power is capacitively coupled to said target.
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8. The apparatus of claim 1, wherein said substrate holder comprises an electrostatic holder configured to apply an electrostatic force to the substrate to hold the substrate.
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9. The apparatus of claim 1 wherein said target is a source of dielectric material to be deposited.
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10. The apparatus of claim 1 wherein said target is a source of conductive material to be deposited.
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11. An apparatus for performing physical vapor deposition of a layer on a substrate, said apparatus comprising:
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a deposition chamber enclosing a plasma region for containing an ionizable gas;
an electromagnetic field generator surrounding said plasma region for inductively coupling an electromagnetic field into said plasma region to ionize the gas and generate and maintain a high density, low potential plasma;
a source of deposition material including a solid target constituting a source of material to be deposited onto the substrate;
an electrical bias circuit associated with said target to electrically bias said target in order to cause ions in the plasma to strike said target and sputter material from said target; and
a substrate holder for holding the substrate at a location to permit material sputtered from said target to be deposited on the substrate, wherein said substrate holder comprises;
an electrostatic holder configured to apply an electrostatic force to the substrate to hold the substrate;
a gas supply configured to supply and bring gas into contact with the substrate;
a heat exchanger configured to remove heat at a high rate from the substrate; and
a voltage bias source adapted to induce a DC bias in the substrate, wherein said electromagnetic field generator comprises;
a source of RF electrical power;
an electrostatic shield surrounding said plasma region; and
a coil surrounding said shield and coupled to said source of RF electrical power for converting RF power from said source into the electromagnetic field that is coupled into said plasma region.
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12. An apparatus for performing physical vapor deposition of a layer on a substrate, said apparatus comprising:
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a deposition chamber enclosing a plasma region for containing an ionizable gas;
an electromagnetic field generator surrounding said plasma region for inductively coupling an electromagnetic field into said plasma region to ionize the gas and generate and maintain a high density, low potential plasma;
a source of deposition material including a solid target constituting a source of conductive material to be deposited onto the substrate;
an electrical bias circuit associated with said target to electrically bias said target in order to cause ions in the plasma to strike said target and sputter material from said target; and
a substrate holder for holding the substrate at a location to permit material sputtered from said target to be deposited on the substrate, wherein said deposition chamber comprises a wall of dielectric material delimiting the plasma region. - View Dependent Claims (13, 14, 15, 16, 17, 18)
the plasma generated in said plasma region has an impedance which constitutes an output impedance of said electromagnetic field generator;
said electromagnetic field generator comprises;
a source of RF electrical power, and an impedance matching network coupled between said source and said plasma region for maintaining efficient energy transfer from said source to the plasma generated in said plasma region, said impedance matching network having at least one electrical component having a component impedance which varies in response to variations in the impedance of the plasma; and
said apparatus further comprises a monitoring component coupled to said electrical component configured to monitor the component impedance and to control generation of the bias voltage as a function of the monitored component impedance to maintain the thickness below a predetermined value.
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18. The apparatus of claim 13 wherein:
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the plasma generated in said plasma region has an impedance which constitutes an output impedance of said electromagnetic field generator;
said electromagnetic field generator comprises a source of variable frequency RF electrical power having a frequency which varies in response to variations in the impedance of the plasma; and
said apparatus further comprises a voltage-frequency monitoring component coupled to said source of variable frequency RF electrical power electrical to monitor the frequency of electrical power and to control generation of the bias voltage as a function of the monitored frequency to maintain the thickness below a predetermined value.
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19. A method for performing physical vapor deposition of a layer on a substrate, said method comprising:
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providing a deposition chamber enclosing a plasma region and containing a solid target constituting a source of conductive material to be deposited in vapor form onto the substrate, and a substrate holder holding the substrate;
introducing an ionizable gas into the plasma region;
inductively coupling an electromagnetic RF field into the plasma region under conditions to ionize the gas and create a high density, low potential plasma;
biasing the target in order to cause ions in the plasma to strike the target and sputter material from the target; and
causing material sputtered from the target to be deposited as a layer on the substrate, wherein the deposition chamber comprises a wall of dielectric material delimiting the plasma region. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28)
said inductively coupling an electromagnetic RF field into the plasma region comprises;
generating RF electrical power from a power source, and coupling the RF electrical power from the source to the plasma region via an impedance matching network that maintains efficient energy transfer from the source to the plasma generated in said plasma region, said impedance matching network having at least one electrical component having a component impedance which varies in response to variations in the impedance of the plasma;
the plasma generated in the plasma region has an impedance which constitutes an output impedance of the power source; and
said monitoring the thickness of material deposited on the wall comprises determining the value of the component impedance and controlling generation of the bias voltage as a function of the component impedance value to maintain the thickness of the material deposited on the wall below a predetermined value.
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28. The method of claim 24 wherein:
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said inductively coupling an electromagnetic RF field into the plasma region comprises generating RF electrical power from a source of variable frequency RF electrical power having a frequency which varies in response to variations in the impedance of the plasma;
the plasma generated in the plasma region has an impedance which constitutes an output impedance of the power source; and
said monitoring the thickness of material deposited on the wall comprises determining the frequency of the electrical power and controlling generation of the bias voltage as a function of the determined frequency to maintain the thickness of the material deposited on the wall below a predetermined value.
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Specification