Vapor deposition of polymer films for photolithography
First Claim
1. A plasma synthesized polymer film disposed on a semiconductor wafer, the film having C--C bonds, C--H bonds, and plasma synthesized O--H bonds, the film having a level of oxygen constituency that is selected to provide a ratio of O--H bond concentration to C--H bond concentration that yields substantially a prespecified concentration of reactive silylation sites in the film.
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Abstract
The invention provides a method for vapor-depositing a polymer film having constituents that are synthesized during the deposition and that can therefore be customized by time-dependent process control during the deposition. In the vapor-deposition process, a hydrocarbon precursor is reacted with an oxygen-containing precursor in a plasma environment. The plasma reaction synthesizes O--H bonds and forms a polymer having O--H bonds, C--C bonds, and C--Hx bonds. Preferably, the hydrocarbon and oxygen-containing precursors are employed in a ratio selected such that the resulting polymer film has a selected level of oxygen constituency providing a corresponding selected ratio of O--H bond concentration to C--Hx bond concentration. The precursor ratio is preferably varied as a function of time during the plasma reaction to result in a corresponding distribution, e.g., a depth-dependent distribution, of O--H bonds in the film. The vapor-deposited polymer film provided by the invention is particularly well-suited as an all-dry positive-tone silylation photoresist because the vapor-deposition process can custom-synthesize a constituent hydroxyl group concentration and distribution in the photoresist film for a given photolithographic application.
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Citations
14 Claims
- 1. A plasma synthesized polymer film disposed on a semiconductor wafer, the film having C--C bonds, C--H bonds, and plasma synthesized O--H bonds, the film having a level of oxygen constituency that is selected to provide a ratio of O--H bond concentration to C--H bond concentration that yields substantially a prespecified concentration of reactive silylation sites in the film.
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2. A plasma synthesized polymer film having C--C bonds, C--H bonds, and plasma synthesized O--H bonds, the film having a level of oxygen constituency that is selected to provide a corresponding selected ratio of O--H bond concentration to C--H bond concentration, the O--H bond concentration being distributed through film depth from a relatively higher concentration at shallow depths to a relatively lower concentration at lower depths.
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3. A plasma synthesized polymer film having C--C bonds, C--H bonds, and plasma synthesized O--H bonds the film having a level of oxygen constituency that is selected to provide a corresponding selected ratio of O--H bond concentration to C--H bond concentration, the O--H bond concentration being distributed through film depth from a relatively lower concentration at shallow depths to a relatively higher concentration at central depths and substantially zero concentration at lower depths.
Specification