Method for fabricating semiconductor device, and electro-optical device, integrated circuit and electronic apparatus including the semiconductor device

• US 7,547,589 B2
• Filed: 05/07/2004
• Issued: 06/16/2009
• Est. Priority Date: 05/15/2003
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Iriguchi, Chiharu
• Primary Examiner(s): TRINH, MICHAEL MANH
• Application Number:
  US10/840,297
• Publication Number:
  US 20050026340A1
• Time in Patent Office: 1,866 Days
• Field of Search: 438/149, 438/154, 438/197, 438/151, 438/164, 438/585
• US Class Current: 438/149
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1288 employing particular masking sequences or specially adapted masks, e.g. half-tone mask

Abstract

The invention provides a technique that enables formation of minute patterns on an uneven substrate in volume production without reducing productivity. The method for fabricating a semiconductor device includes: first patterning a semiconductor film on a substrate to form element regions, each of which will be provided with a source/drain region and a channel region, second forming a gate insulating film covering segments of the patterned semiconductor film in the respective element regions, third forming gate electrodes on the gate insulating film at predetermined positions, and fourth forming the source/drain region and the channel region in each element region. At least the gate electrodes are formed by a process including an exposure step through a holographic exposure mask in the third step, and by a process including an exposure step through a projection exposure mask, the element regions are formed in the first step, and the source/drain regions and the channel regions are formed in the fourth step.

Claims

1. A method for fabricating a semiconductor device including transistors, each having a gate electrode, a source/drain region, and a channel region on a substrate, the method comprising:

first, patterning a semiconductor film on the substrate to form element regions, each to be provided with the source/drain region and the channel region, the first patterning step including;

forming a second photosensitive film on the semiconductor film using a photosensitive material,

exposing the second photosensitive film through a first projection exposure mask using a stepper or a scanner, the first projection exposure mask having an exposure pattern corresponding to the element regions and an exposure pattern corresponding to a first alignment mark used for alignment of a holographic exposure mask,

developing the exposed second photosensitive film and removing the second photosensitive film excluding areas corresponding to the element regions and an area corresponding to the first alignment mark, and

etching the conductive film through the second photosensitive film, as a mask, remaining on the semiconductor film to form the element regions and the first alignment mark;

second, forming a gate insulating film covering segments of the patterned semiconductor film in the respective element regions;

third, forming the gate electrodes on the gate insulating film at predetermined positions; and

fourth, forming the source/drain region and the channel region in each of the element regions, the gate electrodes being formed by a process including an exposure step through the holographic exposure mask in the third step and the source/drain regions and the channel regions being formed by a process including an exposure step through a projection exposure mask using a stepper or a scanner in the fourth step.

2. The method for fabricating a semiconductor device according to claim 1, the first projection exposure mask including an exposure pattern corresponding to a second alignment mark used in the second step and the subsequent steps, and the second alignment mark being formed in the first step.

3. The method for fabricating a semiconductor device according to claim 2, the fourth step including:

forming a third photosensitive film over the element regions using a photosensitive material, the element regions corresponding to the respective transistors;

exposing the third photosensitive film through a second projection exposure mask having an exposure pattern distinguishing the element regions for formation of the source/drain region and the channel region from the element regions not for the formation of the source/drain region and the channel region;

developing the exposed third photosensitive film and removing the third photosensitive film excluding areas corresponding to the element regions not for the formation of the source/drain region and the channel region; and

introducing an impurity to an area intended for the source/drain region within each of the element regions for the formation of the source/drain region and the channel region to form the source/drain regions and the channel regions,

the second projection exposure mask being aligned by referring to the second alignment mark.

4. The method for fabricating a semiconductor device according to claim 3, the number of regions subjected to exposure in the holographic exposure mask being an integral multiple of that in the first projection exposure mask or the second projection exposure mask.

5. The method for fabricating a semiconductor device according to claim 3, each of the first projection exposure mask and the second projection exposure mask being at least one of a reticle of a stepper and a scanner.

6. The method for fabricating the semiconductor device according to claim 1,

the substrate being glass.

7. A method of fabricating a semiconductor device, comprising:

forming a semiconductor film over a substrate;

forming a first photosensitive film over the semiconductor film;

exposing the first photosensitive film through a first projection exposure mask having a first exposure pattern corresponding to an element region and a first alignment mark;

forming the element region and the first alignment mark by patterning the semiconductor film;

forming an insulating film over the element region;

forming a conductive film over the insulating film;

forming a second photosensitive film over the conductive film;

exposing the second photosensitive film through a holographic exposure mask having a second exposure pattern corresponding to an electrode, the holographic exposure mask being aligned with the first alignment mark;

forming the electrode over the insulating film by patterning the conductive film; and

forming a source/drain region and a channel region in the element region, the source/drain region and the channel region being formed by a process including an exposure step through a projection exposure mask using a stepper or a scanner.

8. The method of fabricating a semiconductor device according to claim 7, in the process of exposing the first photosensitive film, the first exposure pattern further corresponding to a second alignment mark, in the process of forming the element region and the first alignment mark including forming the second alignment mark, further comprising:

forming a third photosensitive film over the electrode; and

exposing the third photosensitive film through a second projection exposure mask, the second projection mask being aligned with the second alignment mark.

9. The method of fabricating a semiconductor device according to claim 7, the process of exposing the first photosensitive film including moving the first projection exposure mask by a stepper.

10. The method of fabricating a semiconductor device according to claim 7, the process of exposing the second photosensitive film including moving the holographic exposure mask by a holographic exposure system.

11. The method of fabricating a semiconductor device according to claim 7, the first photosensitive film being exposed a plurality of times in the process of exposing the first photosensitive film, the second photosensitive film being exposed a plurality of times in the process of exposing the second photosensitive film, a number of regions that is exposed in the process of exposing the second photosensitive film being an integral multiple of a number of regions that is exposed in the process of exposing the first photosensitive film.

12. The method of fabricating a semiconductor device according to claim 7, the electrode being a gate electrode that includes at least one of tantalum and aluminum.

13. A method of forming an electro-optical device, comprising:

fabricating a semiconductor device according to claim 7.

14. A method of forming an integrated circuit, comprising:

fabricating a semiconductor device according to claim 7.

15. A method of forming a circuit substrate, comprising:

fabricating a semiconductor device according to claim 7.

16. A method of forming an electronic apparatus, comprising:

fabricating a semiconductor device according to claim 7.

17. A method of fabricating a semiconductor device, comprising:

providing an element region made of a silicon and a first alignment mark over a substrate;

forming an insulating film over the element region;

forming a conductive film over the insulating film;

forming a second photosensitive film over the conductive film;

exposing the second photosensitive film through a holographic exposure mask having a second exposure pattern corresponding to an electrode, the holographic exposure mask being aligned with the first alignment mark; and

forming the electrode over the insulating film by patterning the conductive film,

wherein the element region and the first alignment mark are formed by exposing the first photosensitive film through a first projection exposure mask having a first exposure pattern corresponding to the element region and the first alignment mark, the element region having a source/drain region and a channel region, the source/drain region and the channel region being formed by a process including an exposure step through a projection exposure mask using a stepper or a scanner.