Anisotropic etch method

A method to anisotropically etch at least one layer in a group of layers consisting of a silicide layer a polycrystalline silicon layer, and a polycide layer located over a layer of gate oxide on a substrate, said anisotropical etch producing a profile at or near 90° from horizontal with respect to said substrate in a parallel plate plasma etch reactor having a first electrode and an inert second electrode comprised of anodized aluminum, said first electrode and said inert second electrode having gap therebetween, said method comprising:

• providing a gap within the range of approximately 0.5 cm to 2.5 cm;
• mounting said substrate on said first electrode;
• and
• providing a plasma atmosphere within said parallel plate plasma etch reactor including Cl2 and He, a pressure within the range of approximately 0.200 to 0.550 torr, and a plasma power density within the range of approximately 0.18 to 2.0 W/cm2;
• and
• anisotropically etching said at leas one layer in said group of layers consisting of said silicide layer, said polycrystalline silicon layer, and said polycide layer located over said layer of gate oxide.

A method to anisotropically etch at least one layer in a group of layers consisting of a silicide layer, a polycrystalline silicon layer, and a polycide layer located on a portion of a substrate, said anisotropical etch producing a profile at or near 90° from horizontal with respect to said substrate using a parallel plate plasma etch reactor including a first electrode and an inert second electrode comprised of anodized aluminum, said first electrode and said inert second electrode having a gap therebetween, said method comprising:

• providing a gap within the range of approximately 0.8 cm to 1.5 cm;
• mounting said substrate on said first electrode;
• and
• providing a plasma atmosphere w thin said parallel plate plasma etch reactor including Cl2 and He, a pressure within the range of approximately 0.300 torr to 0.425 torr, and a plasma power density within the range of approximately 0.18 W/cm2 to 2.0 W/cm2 to anisotropically etch said a least one layer in said group of layers comprising said silicide layer, said polycrystalline silicon layer, and said polycide layer located on said portion of said substrate.

A method to anisotropically etch a structure in situ to produce a profile at or near 90° from horizontal with respect to said structure, said structure including a first layer of an oxide of silicon on a second layer selected from the group consisting of silicide, polycrystalline silicon, and polycide, said structure located on a substrate, said anisotropic etch comprising using a parallel plate plasma etch reactor including a first electrode and an inert second electrode comprised of anodized a aluminum, said first electrode and said inert second electrode having a gap therebetween, said method comprising:

• placing said substrate on said first electrode;
• providing a first high pressure at sphere within said parallel plate plasma etch reactor, said first high pressure atmosphere including C2F6, CHF3, CF4, and He;
• exposing said first layer to a first plasma having a first high power density to expose at least a portion of said second lay
• overetching said first layer to substantially remove said oxide of silicon;
• providing a second high pressure atmosphere within said parallel plate plasma etch reactor including Cl2 and He;
• and
• exposing said second layer to a second plasma having a second high power density.