Method for manufacturing a liquid crystal display apparatus

• US 6,190,951 B1
• Filed: 07/02/1999
• Issued: 02/20/2001
• Est. Priority Date: 07/06/1998
• Status: Expired due to Term

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Advanced Display Technologies
• Inventors: Nakahori, Tadaki, Fujiwara, Masakuni, Yasuda, Harumi
• Primary Examiner(s): Bowers, Charles
• Assistant Examiner(s): MENZ, LAURA MARY
• Application Number:
  US09/346,725
• Time in Patent Office: 599 Days
• Field of Search: 438/151, 438/152, 438/153, 257/292, 257/293, 257/294, 257/295, 257/435, 257/436, 257/443, 349/137, 349/110, 349/38, 349/111, 459/88
• US Class Current: 438/151
• CPC Class Codes: G02F 1/133302 Rigid substrates, e.g. inorganic substrates
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 21/28008 Making conductor-insulator-semiconductor electrodes
• CPC Class Codes: H01L 21/32134 by liquid etching only
• CPC Class Codes: H01L 29/66765 Lateral single gate single channel transistors with inverted structure, i.e. the channel layer is formed after the gate

Abstract

The present invention is directed to method for manufacturing a liquid crystal display apparatus in which a thin film transistor formed by successively depositing on a glass substrate a gate electrode, a gate insulating film, an active layer made of amorphous silicon, a source electrode and a drain electrode is used for driving liquid crystal. The method includes steps of: forming the gate electrode by patterning a gate metal layer coating the glass substrate by a wet etching process using an etchant containing cerium ammonium nitrate; removing an etching reaction product adhering on the substrate by washing it with a hydrofluoric acid solution; and forming the gate insulating film.

Claims

1. Method for manufacturing a liquid crystal display apparatus in which a thin film transistor formed by successively depositing on a glass substrate a gate electrode, a gate insulating film, an active layer made of amorphous silicon, a source electrode and a drain electrode is used for driving liquid crystal, said method comprising steps of:

forming the gate electrode by patterning a gate metal layer coating the glass substrate by a wet etching process using an etchant containing cerium ammonium nitrate;

removing an etching reaction product adhering on the substrate by washing it with a hydrofluoric acid solution; and

forming the gate insulating film.

2. The method of claim 1, wherein the hydrofluoric acid solution is a buffered hydrofluoric acid solution having a concentration of 0.5 to 1%, or a dilute hydrofluoric acid solution having a concentration of 0.1 to 0.3%.

3. The method of claim 2, wherein the wet etching process using buffered hydrofluoric acid solution or dilute hydrofluoric solution is subjected for 20 to 30 seconds.

4. The method of claim 1, wherein said insulating film is a single or multi layered film.

5. The method of claim 1, wherein said insulating film is 300 to 500 nm thick.