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

• US 20050026340A1
• Filed: 05/07/2004
• Published: 02/03/2005
• Est. Priority Date: 05/15/2003
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Iriguchi, Chiharu
• Granted Patent: US 7,547,589 B2
• Time in Patent Office: Days
• US Class Current: 438/164
• 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 a transistor having a gate electrode, a source/drain region, and a channel region on a substrate, the method comprising:

forming at least the gate electrode by a process including an exposure step through a holographic exposure mask; and

forming the source/drain region and the channel region by a process including an exposure step through a projection exposure mask.

9. An electro-optical device, comprising:

the semiconductor device fabricated by the method for fabricating a semiconductor device according to claim 1.

10. An integrated circuit, comprising:

the semiconductor device fabricated by the method for fabricating a semiconductor device according to claim 1.

11. A circuit substrate, comprising:

the semiconductor device fabricated by the method for fabricating a semiconductor device according to claim 1.

12. An electronic apparatus, comprising:

the semiconductor device fabricated by the method for fabricating a semiconductor device according to claim 1.

2. 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;

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, at least the gate electrodes being formed by a process including an exposure step through a holographic exposure mask in the third step, the element regions being formed by a process including an exposure step through a projection exposure mask in the first step, and the source/drain regions and the channel regions being formed by a process including an exposure step through a projection exposure mask in the fourth step.

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

forming a conductive film on the gate insulating film;

forming a first photosensitive film on the conductive film using a photosensitive material;

exposing the first photosensitive film through the holographic exposure mask with an exposure pattern corresponding to the gate electrodes;

developing the exposed first photosensitive film and removing the first photosensitive film excluding areas corresponding to the gate electrodes; and

etching the conductive film through the first photosensitive film, as a mask, remaining on the conductive film to form the gate electrodes.

4. The method for fabricating a semiconductor device according to claim 2, the first 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 having an exposure pattern corresponding to the element regions and an exposure pattern corresponding to a first alignment mark used for alignment of the holographic exposure mask in the third step;

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.

5. The method for fabricating a semiconductor device according to claim 4, 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.

6. The method for fabricating a semiconductor device according to claim 5, 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.

7. The method for fabricating a semiconductor device according to claim 6, 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.

8. The method for fabricating a semiconductor device according to claim 6, 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.