Selective etch for silicon films
First Claim
1. A method of etching patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate has an exposed oxygen-and-silicon-containing region and an exposed silicon-containing region which contains less oxygen than the oxygen-and-silicon-containing region, the method comprising:
- flowing a fluorine-containing precursor into a remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the first plasma region to produce plasma effluents; and
etching the silicon-containing region faster than the oxygen-and-silicon-containing region by flowing the plasma effluents into the substrate processing region, wherein the etching is performed while maintaining a partial pressure of the fluorine-containing precursor below about 100 mTorr.
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Abstract
A method of etching patterned heterogeneous silicon-containing structures is described and includes a remote plasma etch with inverted selectivity compared to existing remote plasma etches. The methods may be used to conformally trim polysilicon while removing little or no silicon oxide. More generally, silicon-containing films containing less oxygen are removed more rapidly than silicon-containing films which contain more oxygen. Other exemplary applications include trimming silicon carbon nitride films while essentially retaining silicon oxycarbide. Applications such as these are enabled by the methods presented herein and enable new process flows. These process flows are expected to become desirable for a variety of finer linewidth structures. Methods contained herein may also be used to etch silicon-containing films faster than nitrogen-and-silicon containing films having a greater concentration of nitrogen.
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Citations
20 Claims
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1. A method of etching patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate has an exposed oxygen-and-silicon-containing region and an exposed silicon-containing region which contains less oxygen than the oxygen-and-silicon-containing region, the method comprising:
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flowing a fluorine-containing precursor into a remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the first plasma region to produce plasma effluents; and etching the silicon-containing region faster than the oxygen-and-silicon-containing region by flowing the plasma effluents into the substrate processing region, wherein the etching is performed while maintaining a partial pressure of the fluorine-containing precursor below about 100 mTorr. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of etching patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate has an exposed nitrogen-and-silicon-containing region and an exposed silicon-containing region which contains less nitrogen than the nitrogen-and-silicon-containing region, the method comprising:
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flowing a fluorine-containing precursor into a remote plasma region fluidly coupled to the substrate processing region while forming a plasma in the first plasma region to produce plasma effluents; and etching the silicon-containing region faster than the nitrogen-and-silicon-containing region by flowing the plasma effluents into the substrate processing region, wherein the etching is performed while maintaining a partial pressure of the fluorine-containing precursor below about 100 mTorr. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification