Technique for patterning differently stressed layers formed above transistors by enhanced etch control strategies
First Claim
1. A method, comprising:
- forming a first stress-inducing layer above a first transistor and a second transistor, said first and second transistors formed above a first substrate;
removing a portion of said first stress-inducing layer located above said second transistor;
forming a second stress-inducing layer on said first stress-inducing layer and above a measurement site;
removing a first portion of said second stress-inducing layer from above said first transistor on the basis of an etch process;
forming a test structure including a grating pattern at said measurement site by etching a second portion of said second stress-inducing layer to define said grating pattern; and
controlling at least one parameter of said etch process on the basis of optical measurement data collected from said grating pattern at said measurement site, said optical measurement data indicating an etch rate of said etch process.
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Abstract
During the patterning of stressed layers having different types of intrinsic stress, the effects of the deposition of a silicon dioxide based etch indicator material between the first and second dielectric layers may be significantly reduced by a controlled etch on the basis of optical measurement data indicating the etch rate and, thus, the performance of the respective etch process. In other cases, highly efficient etch indicator species may be incorporated into the stressed dielectric layers or may be formed on a surface portion thereof with reduced layer thickness, thereby providing an enhanced endpoint detection signal without creating the negative effects of silicon dioxide based indicator layers. In one illustrative embodiment, a stressed silicon, nitrogen and carbon-containing layer may be combined with a stressed silicon and nitrogen-containing layer, wherein the carbon species provides a prominent endpoint detection signal.
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Citations
18 Claims
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1. A method, comprising:
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forming a first stress-inducing layer above a first transistor and a second transistor, said first and second transistors formed above a first substrate; removing a portion of said first stress-inducing layer located above said second transistor; forming a second stress-inducing layer on said first stress-inducing layer and above a measurement site; removing a first portion of said second stress-inducing layer from above said first transistor on the basis of an etch process; forming a test structure including a grating pattern at said measurement site by etching a second portion of said second stress-inducing layer to define said grating pattern; and controlling at least one parameter of said etch process on the basis of optical measurement data collected from said grating pattern at said measurement site, said optical measurement data indicating an etch rate of said etch process. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification