Methods to mitigate plasma damage in organosilicate dielectrics using a protective sidewall spacer
First Claim
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1. A method for fabricating an interconnect structure comprising:
- forming an intermetal dielectric layer on a substrate;
forming a via hole in said intermetal dielectric layer and filling a lower portion of said via hole with a disposable via fill material;
forming an interconnect line trench in said intermetal dielectric layer over said via hole;
forming a protective spacer on sidewalls of said interconnect line trench and on sidewalls of an upper portion of said via hole, wherein said protective spacer contains one of silicon dioxide, an organosilicate material with penant alkyl, aryl or allyl groups, and organosilicate materials having linked carbo-silane bonds, and wherein at least a portion of a bottom surface of said interconnect line trench is not covered by said protective spacer; and
performing a plasma strip to remove said disposable via fill material, while said protective spacer protects said intermetal dielectric layer covered by said protective spacer from damage during said plasma strip.
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Abstract
Plasma damage in ultra low k dielectric materials during formation of a dual damascene metal interconnect structure is reduced by providing a protective spacer on sidewalls of a line trench. A densified trench bottom region may be additionally formed directly beneath an exposed horizontal surface of the line trench. The protective spacer and/or the densified trench bottom region protects an ultra low k intermetal dielectric layer from plasma damage during a plasma strip process that is used to remove a disposable via fill plug employed in the dual damascene metal interconnect structure.
18 Citations
14 Claims
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1. A method for fabricating an interconnect structure comprising:
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forming an intermetal dielectric layer on a substrate; forming a via hole in said intermetal dielectric layer and filling a lower portion of said via hole with a disposable via fill material; forming an interconnect line trench in said intermetal dielectric layer over said via hole; forming a protective spacer on sidewalls of said interconnect line trench and on sidewalls of an upper portion of said via hole, wherein said protective spacer contains one of silicon dioxide, an organosilicate material with penant alkyl, aryl or allyl groups, and organosilicate materials having linked carbo-silane bonds, and wherein at least a portion of a bottom surface of said interconnect line trench is not covered by said protective spacer; and performing a plasma strip to remove said disposable via fill material, while said protective spacer protects said intermetal dielectric layer covered by said protective spacer from damage during said plasma strip. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for fabricating an interconnect structure comprising:
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forming an intermetal dielectric layer on a substrate; forming a via hole in said intermetal dielectric layer and filling a lower portion of said via hole with a disposable via fill material; forming an interconnect line trench in said intermetal dielectric layer over said via hole; forming a protective spacer on sidewalls of said interconnect line trench and on sidewalls of an upper portion of said via hole, wherein said protective spacer contains one of silicon oxide, an organosilicate material, an organo-silicate material and having linked carbo-silane bonds, and an organosilicate material with pendant alkyl, aryl or allyl groups, on said intermetal dielectric layer, and wherein a portion of a bottom surface of said interconnect line trench is not covered by said protective spacer; performing a densification treatment on said bottom surface of said interconnect line trench to form a densified trench bottom region; and performing a plasma strip to remove said disposable via fill material, while said protective spacer and said densified trench bottom region protect said intermetal dielectric layer from damage during said plasma strip. - View Dependent Claims (12, 13, 14)
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Specification