Method and apparatus for plasma etching a substrate
First Claim
1. An apparatus for plasma etching of a substrate, comprising:
- a chamber,a gas within the chamber,means for ionizing the gas within the chamber to create a plasma,substrate mounting means for holding the substrate in the plasma,a power supply for electrically biasing the substrate relative to the plasma, andmeans for producing a surface magnetic field confining the plasma within the chamber.
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Reexamination
Accused Products
Abstract
A method and apparatus for plasma etching a substrate, such as a semiconductor wafer, utilizing a multipole surface magnetic field confining within an etching chamber an etching plasma of substantially uniform density throughout its volume. The plasma is produced and maintained by subjecting a gas such as CF4 to an ionizing discharge within the chamber. Only DC power sources are used for the discharge, so that there is virtually no perturbing radio frequency interference produced. The wafer is consequently easily biased relative to the plasma for controlled fine-scale etching. Low gas pressures permitted by the surface magnetic field result in substantially anisotropic etching of the substrate by dense plasma concentrations.
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Citations
35 Claims
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1. An apparatus for plasma etching of a substrate, comprising:
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a chamber, a gas within the chamber, means for ionizing the gas within the chamber to create a plasma, substrate mounting means for holding the substrate in the plasma, a power supply for electrically biasing the substrate relative to the plasma, and means for producing a surface magnetic field confining the plasma within the chamber. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An apparatus for anisotropic plasma etching of a solid substrate, comprising:
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a chamber, said chamber being capable of maintaining a low pressure therein, substrate mounting means for holding the substrate in the plasma, means for electrically biasing the substrate relative to the plasma, and means for producing a multipolar surface magnetic field for confining the plasma in the chamber, whereby the plasma is of substantially unifom density throughout its volume. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. An apparatus for anisotropic etching of a substrate, comprising:
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a low pressure chamber having sides, a top and a bottom, means for producing a plasma within the chamber, substrate mounting means for holding the substrate in the plasma, controllable means for electrically biasing the substrate relative to the plasma, and means for producing a multidipolar surface magnetic field substantially confining the plasma within the chamber as a dense plasma having about 1012 or more charged particles per cubic centimeter, which density is substantially uniform throughout the volume of said plasma to about ±
1%. - View Dependent Claims (21, 22)
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23. An apparatus for plasma etching of a substrate comprising:
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chamber, a cathode and cathode power supply for producing ionizing electrons, an anode and an anode power supply for creating an electrical discharge from the heater element and within the chamber, a gas within the chamber which is ionized by the discharge thereby creating a plasma, substrate mounting means for holding the substrate in the plasma, a controlled power supply communicating with the substrate for electrically biasing the substrate relative to the plasma, and means for producing a multidipolar surface magnetic field confining the plasma within the chamber. - View Dependent Claims (24)
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25. An improved apparatus for plasma etching of a substrate which is carried on a mount within a chamber, wherein an ionizing current is established between a cathode and an anode to thereby ionize a gas confined within the chamber to create a plasma, the substrate being further electrically biasable relative to the plasma, wherein the improvement comprises:
a multidipolar surface magnetic field confining the plasma within the chamber, the surface magnetic field comprising a magnetic boundary to the plasma adjacent the inside chamber wall, whereby a substantially uniform plasma is established within the chamber for etching the substrate therein. - View Dependent Claims (26)
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27. The method of plasma etching of a semi-conductor substrate comprising the steps of:
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placing a masked semiconductor substrate in a chamber, admitting a gas into said chamber at low pressure, producing a multipole surface magnetic field boundary within said chamber, producing an ionizing discharge within said boundary and thereby ionizing said gas to produce a plasma, confining said plasma within said magnetic boundary to provide a uniform plasma environment around said semiconductor substrate, and etching said semiconductor substrate. - View Dependent Claims (28, 29)
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30. A method of etching materials by plasma treatment comprising the steps of:
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introducing a gas into a space defined and surrounded by a surface magnetic field; generating ionizing electrons within said space; ionizing said gas with said electrons to produce an etching plasma within said space; and subjecting a material to be etched to said etching plasma within said space in order to etch said material. - View Dependent Claims (31, 32)
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33. An apparatus for etching materials by plasma treatment comprising:
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means for producing a surface magnetic field, means for introducing a gas into a space defined and surrounded by said surface magnetic field, means for creating an electrical discharge within said space ionizing gas within said space to create a plasma, and means for holding material to be etched within the plasma. - View Dependent Claims (34, 35)
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Specification