MIS semiconductor device having an LDD structure and a manufacturing method therefor

A method of manufacturing a semiconductor device comprising the steps of:

• forming a gate insulating film on a surface of a semiconductor, said gate insulating film comprising an oxide film;
• forming a gate electrode on said gate insulating film;
• first introducing an impurity ion into said semiconductor by using said gate electrode as a mask;
• forming a conductive film over said semiconductor, said conductive film covering said gate insulating film and said gate electrode;
• performing an anisotropic etching said conductive film until a portion of said gate insulating film is exposed, thereby, forming a side wall spacer made of said conductive film adjacent to said gate electrode,
• wherein said anisotropic etching is conducted by applying an electrical energy to a mixture of a halogen fluoride gas and an inert gas, with said semiconductor applied with a negative bias voltage,
• wherein a portion of said conductive film which is damaged by said electrical energy is likely etched by said halogen fluoride gas.

A method of manufacturing a semiconductor device comprising the steps of:

• forming a gate insulating film on a surface of a semiconductor, said gate insulating film comprising an oxide film;
• forming a gate electrode on said gate insulating film;
• first introducing an impurity ion into said semiconductor by using said gate electrode as a mask;
• forming a conductive film over said semiconductor, said conductive film covering said gate insulating film and said gate electrode and having an upper surface parallel with a surface of said substrate and a side surface;
• performing a plasma treatment with a plasma of an inert gas on said conductive film so that a surface condition of said upper surface differs from that of said side surface of the conductive film;
• and
• etching said conductive film with an etchant gas until a portion of said gate insulating film is exposed, thereby forming a side wall spacer made of said conductive film adjacent to said gate electrode,
• wherein a portion of said conductive film which is damaged by said plasma is likely etched by said etchant gas.

A MIS semiconductor device comprising:

• a semiconductor having a channel region therein;
• a gate insulating film on said semiconductor;
• a gate electrode formed on said channel region with said gate insulating film interposed therebetween;
• source and drain regions formed in said semiconductor, with said channel region interposed therebetween;
• a pair of side wall spacers located on said gate insulating film and adjacent to said gate electrode;
• and
• lightly doped regions formed in semiconductor, said lightly doped region located under said side wall spacers, between said source and drain regions and said channel region,
• wherein said side wall spacers is conductive and extends in a same height as said gate electrode.

A method of manufacturing a MIS semiconductor device comprising the steps of:

• forming a gate insulating film on a surface of a semiconductor, said gate insulating film comprising an oxide film;
• forming a gate electrode on said gate insulating film;
• first introducing an impurity ion into said semiconductor by using said gate electrode as a mask;
• forming a film comprising silicon over said gate insulating film and said gate electrode;
• forming a side wall spacer adjacent to side faces of said gate electrode by an anisotropic etching of said film comprising silicon;
• and
• second introducing an impurity ion into said semiconductor by using said gate electrode and said side wall spacer as a mask, thereby, forming lightly doped regions in said semiconductor layer,
• wherein said anisotropic etching is carried out by directing ionized inert gas toward a surface of said film comprising silicon and simultaneously exposing said surface to a halogen fluoride gas,
• wherein said semiconductor is self-biased at -50 to -200 V during the anisotropic etching.

A method of manufacturing a semiconductor device comprising the steps of:

• disposing a substrate having an oxide film thereon and a film on said oxide film to be etched on a cathode in a reaction chamber;
• directing a plasma of an inert gas toward said substrate to cause damage to said film;
• and
• simultaneously exposing said film to an etchant gas so that the damaged surface of said film is selectively etched,
• wherein said substrate was self-biased at -50 to -200 V during etched.

A method of manufacturing a semiconductor device comprising the steps of:

• preparing a substrate having an oxide film thereon and a film on said oxide film to be etched on a cathode in a reaction chamber;
• introducing an inert gas into said reaction chamber;
• forming a plasma of said inert gas between an anode and a grid electrode;
• directing the plasma of said inert gas toward said substrate located on the cathode through said grid electrode;
• introducing an etchant gas into a space between said grid electrode and said substrate, thereby, said surface of the substrate is etched by said etchant gas,
• wherein said substrate is self-biased at -50 to -200 V during etched.