IFC HDP Via Etch Process Development(Jun. 1998 +)

• Goal: Develop high aspect ratio TEOS oxide via etch process in HDP etch tool using iodofluorocarbon (IFC) chemistry; demonstrate substantial (90%+) reduction in emissions; present focus on 1-iodoheptafluoropropane (CF2I-CF2-CF3)

• Process tool: inductively coupled high density plasma etch tool

• Advantages:

  • Higher etch rates than C3F8 are attainable, despite lower F:C ratio in molecule: in one experiment, straight substitution of 1-iodoheptafluoropropane into a C3F8 baseline recipe yielded etch rate increase of ~15%

• Principal challenges:

  • 1997 IFC processes exhibited poor photoresist selectivity and significant taper

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