EP0031704A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Improvements in or relating to apparatus for a reative plasma process
Assignee: Trasformazione Societaria at & T Technologies Inc
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Filing: 1980-12-22
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Granted: —
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Expires: 2000-12-22
Abstract
Abstract The quality of a plasma etching process is improved by withdrawing a small current from the plasma which causes the reaction to produce a uniform, controllable self-bias on a workpiece placed on one plasma energizing electrode. A DC potential supporting the current may be applied by means of a probe (26) positioned in the plasma or to one of the plasma energizing electrodes.
Inventors
- 👤 Birol Kuyel
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 07:36
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32009; H01J37/32082; H01J37/32917; H01J37/32935; H01J37/3299; H01J2237/00; H01J2237/32; H01J2237/33; H01J2237/334; H01J2237/3341; Y; Y10; Y10S; Y10S422/00; Y10S422/906
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
43 words
A reactive gas plasma process wherein a workpiece is exposed to a reactive gas plasma, and characterised in that a DC current is withdrawn from the plasma thereby to control the self-bias which is built-up on at least one surface of the workpiece.
Claim 2
Dependent Claim
43 words
A reactive gas plasma process wherein a workpiece is exposed to a reactive gas plasma, and characterised in that a DC current is withdrawn from the plasma thereby to control the self-bias which is built-up on at least one surface of the workpiece.
Claim 3
Dependent Claim
32 words
A process as claimed in claim 1, wherein the level of current extracted from the plasma is maintained at a substantially constant level despite fluctuations in the parameters of the plasma reaction.
Claim 4
Dependent Claim
28 words
A process as claimed in claim 1 or 2, wherein the current is withdrawn by a variable DC source connected to a probe extending into the plasma region.
Claim 5
Dependent Claim
57 words
A process as claimed in claim 1 or 2, wherein the plasma is created in a reaction chamber including first and second spaced-apart electrodes energized by an AC source, the workpiece is supported by at least the second electrode, and the current is withdrawn by a variable DC source connected to the first electrode through an RF-choke.
Claim 6
Dependent Claim
124 words
Apparatus for a reactive gas plasma process, including a reaction chamber, first and second spaced-apart electrodes within the chamber, the workpiece being supportable by at least the second electrode for exposure to the plasma, means for supplying at least one gas species to the reaction chamber, means for maintaining a predetermined level of vacuum within the chamber and for exhausting spent gases and reaction by-products from the chamber, means for establishing an alternating field between the first and second electrodes thereby to excite the gas species to form a reactive gas plasma, and characterised by means (26,28) for withdrawing, in operation, a predetermined DC current from the plasma thereby to control the self-bias which is built-up at least one surface of the workpiece (14).
Claim 7
Dependent Claim
124 words
Apparatus for a reactive gas plasma process, including a reaction chamber, first and second spaced-apart electrodes within the chamber, the workpiece being supportable by at least the second electrode for exposure to the plasma, means for supplying at least one gas species to the reaction chamber, means for maintaining a predetermined level of vacuum within the chamber and for exhausting spent gases and reaction by-products from the chamber, means for establishing an alternating field between the first and second electrodes thereby to excite the gas species to form a reactive gas plasma, and characterised by means (26,28) for withdrawing, in operation, a predetermined DC current from the plasma thereby to control the self-bias which is built-up at least one surface of the workpiece (14).
Claim 8
Dependent Claim
33 words
Apparatus as claimed in claim 5, wherein the current withdrawing means includes a probe in a region between the first and second electrodes, and a source of DC potential connected to the probe.
Claim 9
Dependent Claim
75 words
Apparatus as claimed in claim 5, wherein the current withdrawing means includes a DC blocking capacitor in a circuit path between the output of the alternating field establishing means and the first electrode, a first RF-choke in a circuit path between a variable source of DC potential and the first electrode, and means for maintaining the current withdrawn from the plasma at a substantially constant level despite fluctuations in the parameters of the plasma reaction.
Claim 10
Dependent Claim
48 words
Apparatus as claimed in claim 7, wherein the current maintaining means includes a voltage- controlled-resistor in a circuit path between variable DC source and a point of fixed potential, and a second RF-choke in a circuit path between the control electrode of the voltagecontrolled-resistor and the second electrode.
Claim 11
Dependent Claim
45 words
Apparatus as claimed in any one of claims 5 to 8, wherein the second electrode is connected to a point of fixed potential through an impedance which is substantially greater than the impedance of either the alternating field establishing means or the variable DC source.
Claim 12
Dependent Claim
24 words
Apparatus as claimed in any one of claims 5 to 9, wherein the alternating field establishing means includes a source of radio frequency energy.
References Cited (Backward Citations)
No citation records indexed.
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