SINGLE-SHOT SEMICONDUCTOR PROCESSING SYSTEM AND METHOD HAVING VARIOUS IRRADIATION PATTERNS

• US 20100197147A1
• Filed: 02/18/2010
• Published: 08/05/2010
• Est. Priority Date: 08/19/2002
• Status: Active Grant

• Current Assignee: James S. Im
• Original Assignee: James S. Im
• Inventors: IM, JAMES S.
• Granted Patent: US 7,906,414 B2
• Time in Patent Office: Days
• US Class Current: 438/798
• CPC Class Codes: B23K 26/066 by using masks
• CPC Class Codes: H01L 21/02 Manufacture or treatment of semiconductor devices or of parts thereof
• 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 21/02675 using laser beams
• CPC Class Codes: H01L 21/02678 Beam shaping, e.g. using a mask
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 21/324 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/20 - H01L21/288 and H01L21/302 - H01L21/322 take precedence
• CPC Class Codes: H01L 27/1285 using control of the annealing or irradiation parameters, e.g. using different scanning direction or intensity for different transistors
• CPC Class Codes: H01L 27/1296 adapted to increase the uniformity of device parameters
• CPC Class Codes: Y10T 117/10 Apparatus
• CPC Class Codes: Y10T 117/1088 including heating or cooling details

Abstract

High throughput systems and processes for recrystallizing thin film semiconductors that have been deposited at low temperatures on a substrate are provided. A thin film semiconductor workpiece is irradiated with a laser beam to melt and recrystallize target areas of the surface exposed to the laser beam. The laser beam is shaped into one or more beamlets using patterning masks. The mask patterns have suitable dimensions and orientations to pattern the laser beam radiation so that the areas targeted by the beamlets have dimensions and orientations that are conducive to semiconductor recrystallization. The workpiece is mechanically translated along linear paths relative to the laser beam to process the entire surface of the work piece at high speeds. Position sensitive triggering of a laser can be used generate laser beam pulses to melt and recrystallize semiconductor material at precise locations on the surface of the workpiece while it is translated on a motorized stage.

Claims

1. A method for recrystallizing a semiconductor thin film to improve its crystalline quality, comprising the steps of

(a) irradiating a first region of a surface of the semiconductor thin film with a pulse of a radiation beam, wherein the radiation beam is first patterned into at least one beamlet in a pattern of beamlets, wherein each beamlet is incident on a target area in the first region, wherein each beamlet has sufficient fluence to melt semiconductor material in the target area on which it is incident, and wherein the molten semiconductor material in the target area recrystallizes when it is no longer exposed to the incident beamlet;

and

(b) continuously translating the semiconductor thin film relative to the radiation beam so that a next region of the surface of the semiconductor thin film is irradiated in the same manner as step (a).

2. The method of claim 1, wherein the beamlets have cross sectional dimensions of the order of a micron.

3. The method of claim 1 further comprising the step of using a mask to pattern the beamlets from the radiation beam pulse.

4. The method of claim 3, wherein the mask comprises:

a blocking portion that blocks through passage of radiation incident on it;

a plurality of slits in a pattern, wherein the slits allow through passage of radiation incident on them, and wherein the slits are disposed substantially parallel to each other in the pattern.

5. The method of claim 3, wherein the mask comprises:

a blocking portion that blocks through passage of radiation incident on it;

a plurality of slits in a pattern, wherein the slits allow through passage of radiation incident on them, and wherein the slits are arranged in pairs along the sides of rectangles in the pattern.

6. The method of claim 1, further the step of comprising supporting the semiconductor thin film on a movable stage, and wherein translating the semiconductor thin film relative to the radiation beam comprises moving the movable stage along a linear path to the next region.

7. The method of claim 6, wherein the semiconductor thin film comprises rows of regions, further comprising moving the movable stage along the linear path through a first row of regions on the surface of the semiconductor thin film.

8. The method of claim 7 wherein the movable stage is moved continuously without pause through the row of regions.

9. The method of claim 7 wherein the movable stage is paused at a region and is then stepped to an adjacent region.

10. The method of claim 7 further comprising moving the movable stage along linear paths through successive rows of regions until the entire surface of the semiconductor thin film has been processed.

11. The method of claim 1 wherein at least one of the target areas in the first region is contiguous to a corresponding target area in the next region, so that after irradiation of the first and next regions an extended strip or recrystallized semiconductor material is fanned.

12. A method for recrystallizing a semiconductor thin film to improve its crystalline quality, comprising the steps of:

(a) using a laser to generate a pulse of a radiation beam;

(b) irradiating a first region of a surface of the semiconductor thin film with the pulse of the radiation beam, wherein the radiation beam is first patterned into at least one beamlet in a pattern of beamlets, wherein each beamlet is incident on a target area in the first region, wherein each beamlet has sufficient fluence to melt semiconductor material in the target area on which it is incident, and wherein the molten semiconductor material in the target area recrystallizes when it is no longer exposed to the incident beamlet; and

(c) after irradiating the first region of the surface of the semiconductor thin film with the pulse of the radiation beam, translating the semiconductor thin film relative to the radiation beam so that a next region of the surface of the semiconductor thin film is irradiated in the manner of steps (a) and (b).

13. The method of claim 12, wherein the laser is triggered to generate the pulse of the radiation beam according to the position of the thin film semiconductor region relative to the radiation beam.

14. The method of claim 12, further comprising supporting the semiconductor thin film on a movable stage, and wherein translating the semiconductor thin film relative to the radiation beam comprises moving the movable stage, and wherein the laser is triggered to generate the pulse of the radiation beam according to the position of the movable stage.

15. The method of claim 14, wherein the position of the movable stage is sensed by position sensors.

16. The method of claim 14, wherein the position of the movable stage is computed from an initial position of the stage.