Apparatus and method for depositing charge on a semiconductor wafer
First Claim
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1. An apparatus for depositing a desired charge on a surface of a semiconductor wafer, said apparatus comprising:
- an ion source;
a conductive screen between said source and said surface, said screen having a plurality of apertures, wherein said apertures flare toward said surface; and
a screen potential control for applying a desired potential to said screen.
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Abstract
A conductive screen is placed between a corona gun and the surface of a semiconductor wafer. The charge deposited on the wafer by the gun is controlled by a potential applied to the screen. A chuck orients the wafer in close proximity to the screen. A desired charge is applied to the wafer by first applying a surplus of one charge to the wafer and then depositing an opposite polarity charge until the potential of the wafer equals the potential of the screen.
149 Citations
17 Claims
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1. An apparatus for depositing a desired charge on a surface of a semiconductor wafer, said apparatus comprising:
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an ion source; a conductive screen between said source and said surface, said screen having a plurality of apertures, wherein said apertures flare toward said surface; and a screen potential control for applying a desired potential to said screen. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for depositing a desired charge on a surface of a semiconductor wafer, said method comprising:
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providing an ion source; providing a conductive screen between said source and said surface, said screen having a plurality of apertures, wherein said apertures flare toward said surface; providing a screen potential control for applying a desired potential to said screen; depositing a first polarity charge on said wafer to provide a surplus of said first polarity charge; applying said desired potential to said screen; and depositing a second polarity charge on said wafer until said wafer has a potential equal to said desired potential. - View Dependent Claims (9)
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10. A method for depositing a desired charge on a surface of a semiconductor wafer, said method comprising:
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providing an alternating polarity ion source; providing a conductive screen between said source and said surface, said screen having a plurality of apertures, wherein said apertures flare toward said surface; providing a screen potential control for applying a desired potential to said screen; applying said desired potential to said screen; and
p1 depositing charge on said wafer until said wafer has a potential equal to said desired potential.
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11. An apparatus for depositing a desired charge on a surface of a semiconductor wafer, said apparatus comprising:
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an ion source; a conductive screen between said source and said surface, said screen having a plurality of apertures; a screen potential control for applying a desired potential to said screen; means to linearly translate said wafer with respect to said apparatus in a linear path to deposit charge on a desired portion of said surface; and means to dither said wafer with respect to said apparatus about said linear path. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification