Method of manufacturing a field effect transistor having an oxide semiconductor

• US 7,968,368 B2
• Filed: 01/28/2010
• Issued: 06/28/2011
• Est. Priority Date: 02/17/2009
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kawamura, Tetsufumi, Uchiyama, Hiroyuki, Saito, Shinichi, Wakana, Hironori
• Primary Examiner(s): LINDSAY JR, WALTER LEE
• Application Number:
  US12/695,361
• Publication Number:
  US 20100210070A1
• Time in Patent Office: 516 Days
• Field of Search: 438/104, 438/149, 438/155, 438/150, 438/151, 257/E21.046, 257/E21.058, 257/E21.039
• US Class Current: 438/104
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

A method of manufacturing a field effect transistor, which has high alignment accuracy between a gate electrode and source and drain electrodes and can provide a transparent device at a low cost. Since a patterned light blocking film is formed on the rear side of a substrate and used as a photomask for forming a gate electrode pattern and a source and drain electrode pattern on the front side of the substrate, the number of photomasks is reduced, and self-alignment between the gate electrode and the source and drain electrodes is carried out, thereby improving the alignment accuracy of these electrodes. Thereby, a method of manufacturing a high-accuracy low-cost field effect transistor can be provided.

Claims

1. A method of manufacturing a field effect transistor having an oxide semiconductor, comprising:

forming a mask pattern for a lower electrode from a light blocking film on the rear side of a substrate made of a translucent material;

carrying out photolithography through the exposure of the rear side of the substrate at least twice using the light blocking film as a mask; and

carrying out self-alignment between the lower electrode and an upper electrode both made of a transparent material.

2. The method of manufacturing a field effect transistor according to claim 1, wherein the lower electrode made of a translucent material is used as a gate electrode and source and drain electrodes are formed after the formation of the gate electrode so as to form a bottom gate structure.

3. The method of manufacturing a field effect transistor according to claim 1, wherein the lower electrode made of a translucent material is used as a source and a drain, and a gate electrode is formed after the formation of the source and drain electrodes to form a top gate structure.

4. The method of manufacturing a field effect transistor according to claim 1, comprising:

forming a channel layer and a source and drain electrode layer,

wherein the step of forming the source and drain electrode layer includes;

applying a negative resist to form a lift-off pattern by photolithography through the exposure of the front side of the substrate;

forming a plurality of the channel layers;

applying a positive resist to form a lift-off pattern by photolithography through the exposure of the rear side of the substrate using the light blocking film as a mask;

forming a plurality of the source and drain electrodes; and

removing the photoresists and lifting off the channel layer and the source and drain electrode layer on the photoresists to form a pattern.

5. The method of manufacturing a field effect transistor according to claim 1, comprising:

forming a channel layer and a source and drain electrode layer,

wherein this step includes;

applying a negative resist to form a lift-off pattern by photolithography through the exposure of the front side of the substrate;

applying a positive resist to form a lift-off pattern by photolithography through the exposure of the rear side of the substrate using the light blocking film as a mask;

forming a plurality of the source and drain electrodes;

lifting off the source and drain electrode layer on the photoresists by removing the photoresists to form a pattern;

applying a negative resist to form a lift-off pattern by photolithography through the exposure of the front side of the substrate;

forming a plurality of the channel layers; and

lifting off the channel layer on the photoresist by removing the resist to form a pattern.

6. The method of manufacturing a field effect transistor according to claim 1, comprising:

forming a channel layer and a source and drain electrode layer,

wherein this step includes;

applying a negative resist to form a lift-off pattern by photolithography through the exposure of the front side of the substrate;

applying a positive resist to form a lift-off pattern by photolithography through the exposure of the rear side of the substrate using the light blocking film as a mask;

forming a plurality of the source and drain electrodes;

lifting off the source and drain electrode film on the photoresists by removing the photoresists to form a pattern;

forming a plurality of the channel layers; and

applying a resist to pattern the channel layer by photolithography through the exposure of the front side of the substrate.

7. The method of manufacturing a field effect transistor according to claim 1, comprising:

forming a channel layer and a source and drain electrode layer,

wherein this step includes;

applying a resist to pattern the channel layer by photolithography through the exposure of the front side of the substrate;

applying a positive resist to form a lift-off pattern by photolithography through the exposure of the rear side of the substrate using the light blocking film as a mask;

forming a plurality of the source and drain electrodes; and

lifting off the source and drain electrode films on the photoresists by removing the photoresists to form a pattern.

8. The method of manufacturing a field effect transistor according to claim 1, comprising:

forming a channel layer and a source and drain electrode layer,

wherein this step includes;

applying a positive resist to form a lift-off pattern by photolithography through the exposure of the rear side of the substrate using the light blocking film as a mask;

forming a plurality of the source and drain electrodes;

lifting off the source/rain electrode films on the photoresist by removing the photoresist to form a pattern;

forming a plurality of the channel layers; and

applying a resist to pattern the channel layers by photolithography through the exposure of the front side of the substrate.

9. A method of manufacturing a transparent device, comprising:

preparing a translucent substrate having a light blocking film with a predetermined pattern on the rear side; and

forming a first translucent electrode pattern and a second translucent electrode pattern on the front side of the translucent substrate by using the light blocking film as a photomask.

10. The method of manufacturing a transparent device according to claim 9, comprising the step of forming a translucent insulating film and the step of forming an oxide film semiconductor layer between the step of forming the first translucent electrode pattern and the step of forming the second translucent electrode pattern.

11. The method of manufacturing a transparent device according to claim 9, comprising the step of forming a translucent insulating film between the step of forming the first translucent electrode pattern and the step of forming the second translucent electrode pattern and the step of forming an oxide film semiconductor layer after the step of forming the second translucent electrode pattern.

12. The method of manufacturing a transparent device according to claim 9, comprising the step of forming a translucent insulating film between the step of forming the first translucent electrode pattern and the step of forming the second translucent electrode pattern and the step of forming an oxide film semiconductor layer before the step of forming the first translucent electrode pattern.

13. The method of manufacturing a transparent device according to claim 9, comprising the step of forming an oxide film semiconductor layer and the step of forming a translucent insulating film between the step of forming the first translucent electrode pattern and the step of forming the second translucent electrode pattern.

14. A method of manufacturing a field effect transistor, comprising:

preparing a translucent substrate having a light blocking film with a predetermined pattern on the rear side; and

forming a translucent gate electrode pattern and a translucent source and drain electrode pattern on the front side of the translucent substrate by using the light blocking film as a photomask.

15. The method of manufacturing a field effect transistor according to claim 14, comprising the step of forming a translucent gate insulating film and the step of forming an oxide film semiconductor layer which will become a channel between the step of forming the translucent gate electrode pattern and the step of forming the translucent source and drain electrode pattern.

16. The method of manufacturing a field effect transistor according to claim 14, comprising the step of forming a translucent gate insulating film between the step of forming the translucent gate electrode pattern and the step of forming the translucent source and drain electrode pattern and the step of forming an oxide film semiconductor layer which will become a channel after the step of forming the translucent source and drain electrode pattern.

17. The method of manufacturing a field effect transistor according to claim 14, comprising the step of forming a translucent gate insulating film between the step of forming the translucent source and drain electrode pattern and the step of forming the translucent gate electrode pattern and the step of forming an oxide film semiconductor layer which will become a channel before the step of forming the translucent source and drain electrode pattern.

18. The method of manufacturing a field effect transistor according to claim 14, comprising the step of forming an oxide film semiconductor layer which will become a channel and the step of forming a translucent gate insulating film between the step of forming the translucent source and drain electrode pattern and the step of forming the translucent gate electrode pattern.

19. The method of manufacturing a field effect transistor according to claim 14, further comprising the step of removing the light blocking film from the translucent substrate after the step of forming the translucent gate electrode pattern and the translucent source and drain electrode pattern on the front side of the translucent substrate.