High pressure high non-reactive diluent gas content high plasma ion density plasma oxide etch process
First Claim
1. A method of performing an etch process on a semiconductor workpiece in a plasma reactor chamber, comprising:
- providing a vacuum pump having a vacuum pump rate to evacuate the plasma reactor chamber;
supplying a polymer and etchant precursor gas containing at least carbon and fluorine into said chamber at a first flow rate sufficient of itself to maintain a gas pressure in said chamber in a low pressure range below about 20 mT;
establishing a high pressure range above 20 mT within said chamber for performing said etch process to define an etch structure comprising increasing said gas pressure in said chamber from said low pressure range to said high pressure range by adding a relatively non-reactive gas into said chamber at a second flow rate sufficient, in combination with the first flow rate of said precursor gas, to maintain said gas pressure in said high pressure range without requiring a decrease in the vacuum pump rate so as to increase polymer passivation strength without otherwise significantly increasing polymer precursor residence time;
continuously maintaining said gas pressure in said high pressure range during said etch process by continuously adding said relatively non-reactive gas into said chamber at said second flow rate; and
applying plasma source power into said chamber to form a high ion density plasma having an ion density in excess of 1010 ions per cubic centimeter.
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Accused Products
Abstract
The invention is embodied in a method of processing a semiconductor workpiece in a plasma reactor chamber, including supplying a polymer and etchant precursor gas containing at least carbon and fluorine into the chamber at a first flow rate sufficient of itself to maintain a gas pressure in the chamber in a low pressure range below about 20 mT, supplying a relatively non-reactive gas into the chamber at second flow rate sufficient about one half or more of the total gas flow rate into the chamber, in combination with the first flow rate of the precursor gas, to maintain the gas pressure in the chamber in a high pressure range above 20 mT, and applying plasma source power into the chamber to form a high ion density plasma having an ion density in excess of 1010 ions per cubic centimeter. In one application of the invention, the workpiece includes an oxygen-containing overlayer to be etched by the process and a non-oxygen-containing underlayer to be protected from etching, the precursor gas dissociating in the plasma into fluorine-containing etchant species which etch the oxygen-containing layer and carbon-containing polymer species which accumulate on the non-oxygen-containing underlayer. Alternatively, the high pressure range may be defined as a pressure at which the skin depth of the inductive field exceeds {fraction (1/10)} of the gap between the inductive antenna and the workpiece.
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Citations
24 Claims
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1. A method of performing an etch process on a semiconductor workpiece in a plasma reactor chamber, comprising:
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providing a vacuum pump having a vacuum pump rate to evacuate the plasma reactor chamber;
supplying a polymer and etchant precursor gas containing at least carbon and fluorine into said chamber at a first flow rate sufficient of itself to maintain a gas pressure in said chamber in a low pressure range below about 20 mT;
establishing a high pressure range above 20 mT within said chamber for performing said etch process to define an etch structure comprising increasing said gas pressure in said chamber from said low pressure range to said high pressure range by adding a relatively non-reactive gas into said chamber at a second flow rate sufficient, in combination with the first flow rate of said precursor gas, to maintain said gas pressure in said high pressure range without requiring a decrease in the vacuum pump rate so as to increase polymer passivation strength without otherwise significantly increasing polymer precursor residence time;
continuously maintaining said gas pressure in said high pressure range during said etch process by continuously adding said relatively non-reactive gas into said chamber at said second flow rate; and
applying plasma source power into said chamber to form a high ion density plasma having an ion density in excess of 1010 ions per cubic centimeter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method of performing an etch process on a workpiece in a plasma reactor chamber, comprising:
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supplying a polymer and etchant precursor gas containing at least carbon and fluorine into said chamber at a first flow rate sufficient of itself to maintain a gas pressure in said chamber in a low pressure range below about 20 mT;
establishing a high pressure range above 20 mT within said chamber for performing said etch process to define an etch structure by increasing said gas pressure in said chamber from said low pressure range to said high pressure range by adding a relatively non-reactive gas into said chamber at a second flow rate sufficient, in combination with the first flow rate of said precursor gas, to maintain said gas pressure in said high pressure range without requiring a decrease in the vacuum pump rate so as to increase polymer passivation strength without otherwise significantly increasing polymer precursor residence time;
continuously maintaining said gas pressure in said high pressure range during said etch process by continuously adding said relatively non-reactive gas into said chamber at said second flow rate; and
applying plasma source power into said chamber to form a high ion density plasma having an ion density in excess of 1010 ions per cubic centimeter. - View Dependent Claims (24)
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Specification