Method of manufacturing semiconductor chips for display

• US 6,248,606 B1
• Filed: 12/22/1998
• Issued: 06/19/2001
• Est. Priority Date: 05/02/1994
• Status: Expired due to Term

• Current Assignee: Japan Display West Incorporated (Japan Display Incorporated)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Minegishi, Masahiro, Urazono, Takenobu, Kunii, Masafumi, Ino, Masumitsu, Hayashi, Hisao, Nishihara, Shizuo
• Primary Examiner(s): Le, Vu A.
• Assistant Examiner(s): LEBENTRITT, MICHAEL
• Application Number:
  US09/219,137
• Time in Patent Office: 910 Days
• Field of Search: 438/30, 438/166, 438/150, 438/487, 438/151
• US Class Current: 438/30
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 29/66757 Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate

Abstract

In a method of manufacturing semiconductor chips for display, a semiconductor thin film is first formed on an insulating substrate, and then a series of processes including a heat-treatment process for the semiconductor thin film are carried out to form integrated thin film transistors on a sectioned area for one chip. Thereafter, pixel electrodes for one picture (frame) are formed within the sectioned area. During the series of processes, a laser pulse is irradiated onto the sectioned area by one shot to perform a heat treatment on the semiconductor thin film for one chip collectively and simultaneously (i.e., perform a batch heat treatment on the semiconductor thin film). Through the batch heat treatment, the crystallization of the semiconductor thin film is promoted. In addition, after the semiconductor thin film is doped with impurities, the activation of impurities doped in the semiconductor thin film can be performed by the batch heat treatment.

Claims

1. A method of manufacturing a wafer including a plurality of array substrates each including a matrix array for a display and a peripheral circuit, comprising the steps of:

providing an insulating wafer substrate including a surface;

forming a semiconductor thin film on said insulating wafer substrate;

processing the semiconductor thin film to form integrated thin film transistors each of which comprises a polycrystalline semiconductor thin film as an active layer, said processing step including a step of irradiating a rectangular-shaped pulsed laser to crystallize a sectional area of the semiconductor thin film by a single shot, one sectional area at a time, said pulsed laser having a duration time of about 40 nanoseconds or more.

2. The method as claimed in claim 1, wherein said laser-irradiation step includes a step of irradiating a one-shot laser pulse onto an individual sectioned area except for a separation band which is provided between neighboring sectioned areas.

3. The method as claimed in claim 1, wherein said laser-irradiation step includes a step of controlling the temperature of the insulating substrate to control the crystallization of the semiconductor thin film.

4. The method as claimed in claim 1, wherein said laser-irradiation step includes a step irradiating a one-shot laser pulse through a microlens array to selectively concentrate the laser pulse on a portion of the semiconductor thin film which corresponds to an element area of an individual thin film transistor.

5. The method as claimed in claim 1, wherein said semiconductor film forming step includes a step of forming the semiconductor thin film at a thickness which is smaller than a laser pulse absorption depth.

6. The method as claimed in claim 1, wherein said laser-irradiation step includes a step of irradiating the one-shot laser pulse while controlling the cross-section intensity distribution of the laser pulse so that the irradiation energy density increases more from the central portion of a sectioned area toward the peripheral portion thereof.

7. The method as claimed in claim 1, wherein said laser-irradiation step includes a step of irradiating the laser pulse in an oblique direction to the insulating substrate.

8. The method as claimed in claim 7, wherein said oblique laser irradiation step includes a step of irradiating the laser pulse at an incident angle of 30°

to 60°

to a normal direction of the insulating substrate.

9. The method as claimed in claim 7, wherein said oblique laser irradiation step includes a step of crystallizing the semiconductor thin film of amorphous silicon by a batch heat treatment.

10. The method as claimed in claim 9, wherein said oblique laser irradiation step includes a step of performing the batch heat treatment in a state where the insulating substrate is maintained at a temperature of 550°

C. to 650°

, thereby promoting the crystallization of amorphous silicon.

11. A method as defined in claim 1, wherein a sectional area has a rectangular configuration and the laser pulse has a rectangular configuration.

12. A method as defined in claim 1, further comprising the step of doping the semiconductor thin film with impurities before said irradiation step.

13. A method as defined in claim 1, wherein the semiconductor thin film formed on the insulating wafer surface comprises amorphous or polycrystal silicon.

14. A method as defined in claim 1, wherein in said irradiation step an eximer laser pulse is employed having a wavelength of 300 nm to 350 nm, an energy density of about 200 mJ/cm² to about 400 mJ/cm², a pulse time of 40 nanoseconds or more and a laser absorption depth of about 160 nm.