Reflection type liquid crystal display device with half tone exposure and method for making same

A method of making a reflection type liquid crystal display device comprising the steps of:

• forming a source and a drain on an insulating substrate;
• forming a thin film transistor and gate electrode wiring in a stack in which a silicon layer, a gate insulating film and a gate electrode layer are stacked in this order as viewed in a direction substantially normal to the substrate on surfaces of the source and drain and the substrate;
• forming a passivation film on the insulating substrate, the passivation film having a first opening therethrough corresponding to a position of the source;
• forming an interlayer insulating film on the passivation film;
• roughening a surface of the interlayer insulating film;
• forming a second opening through the interlayer insulating film in a position corresponding to the first opening,
• wherein the steps of roughening the surface of the interlayer insulating film and of forming the second opening are carried out simultaneously;
• and
• forming a reflection electrode on the roughened surface of the interlayer insulating film and through the first and second openings to the source, the reflection electrode having a roughness corresponding to a roughness of the roughened surface of the interlayer insulating film and being electrically connected to the source,
• wherein the steps of roughening the surface of the interlayer insulating film and of forming the second opening are carried out simultaneously by a photolithography and etching process utilizing half-tone exposure and two-times exposure.

A method of making a reflection type liquid crystal display device comprising the steps of:

• forming a source and a drain on an insulating substrate;
• forming a thin film transistor and gate electrode wiring in a stack in which a silicon layer, a gate insulating film and a gate electrode layer are stacked in this order as viewed in a direction substantially normal to the substrate on surfaces of the source and drain and the substrate;
• forming a passivation film on the insulating substrate, the passivation film having a first opening therethrough corresponding to a position of the source;
• forming an interlayer insulating film on the passivation film;
• roughening a surface of the interlayer insulating film;
• forming a second opening through the interlayer insulating film in a position corresponding to the first opening,
• wherein the steps of roughening the surface of the interlayer insulating film and of forming the second opening are carried out simultaneously;
• and
• forming a reflection electrode on the roughened surface of the interlayer insulating film and through the first and second openings to the source, the reflection electrode having a roughness corresponding to a roughness of the roughened surface of the interlayer insulating film and being electrically connected to the source,
• wherein the rough surface of the interlayer insulating film and the second opening are formed by treating the substrate by a half-tone exposure method in which an exposure mask controls a transmissivity of light.

A method of making a reflection type liquid crystal display device, comprising:

• forming a passivation film on an insulating substrate, the passivation film having a first opening therethrough corresponding to a position of the source;
• forming an interlayer insulating film on the passivation film;
• roughening a surface of the interlayer insulating film;
• and
• forming a second opening through the interlayer insulating film in a position corresponding to the first opening,
• wherein the steps of roughening the surface of the interlayer insulating film and of forming the second opening are carried out simultaneously;
• and
• forming a reflection electrode on the roughened surface of the interlayer insulating film and through the first and second openings to the source, the reflection electrode having a roughness corresponding to a roughness of the roughened surface of the interlayer insulating film,
• wherein the rough surface of the interlayer insulating film and the second opening are formed by treating the substrate by a halftone exposure method in which an amorphous silicon exposure mask controls a transmissivity of light utilizing half-tone exposure and two-times exposure.