High-efficiency line-forming optical systems and methods for defect annealing and dopant activation

Patent metadata

Field	Value
Publication number	US-9613815-B2
Application number	US-201514929186-A
Country	US
Kind code	B2
Filing date	Oct 30, 2015
Priority date	Nov 24, 2014
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

High-efficiency line-forming optical systems and methods for defect annealing and dopant activation are disclosed. The system includes a CO 2 -based line-forming system configured to form at a wafer surface a first line image having between 2000 W and 3000 W of optical power. The line image is scanned over the wafer surface to locally raise the temperature up to a defect anneal temperature. The system can include a visible-wavelength diode-based line-forming system that forms a second line image that can scan with the first line image to locally raise the wafer surface temperature from the defect anneal temperature to a spike anneal temperature. Use of the visible wavelength for the spike annealing reduces adverse pattern effects and improves temperature uniformity and thus annealing uniformity.

First claim

What is claimed is:

1. A system for performing defect annealing of a semiconductor wafer having a surface with a pattern, comprising:
a CO 2 laser source that emits an initial light beam having a wavelength of nominally 10.6 microns;
a beam-conditioning optical system that receives the initial light beam and forms therefrom a conditioned light beam having a first intensity profile with a Gaussian distribution in at least a first direction;
a first aperture device operably disposed at an object plane and that defines a first slit aperture that truncates the first intensity profile in the first direction to define first transmitted light that constitutes at least 50% of the conditioned light beam;
a relay optical system that defines the object plane and that also defines an intermediate focal plane at which is operably disposed a second aperture device, the relay optical system defining at the intermediate focal plane a second intensity profile having a central peak and first side peaks immediately adjacent the central peak, wherein the second aperture device is configured to truncate the second intensity profile in the first direction and within each of the first side peaks to define second transmitted light;
wherein the relay optical system forms from the second transmitted light a first line image at the wafer surface, wherein the first line image includes between 2000 W and 3000 W of optical power, has a first length in the range from 5 mm to 100 mm, and has an intensity uniformity of within +/−5%;
a chuck that operably supports the wafer; and
a moveable wafer stage that operably supports the chuck and that is configured to move the chuck and the wafer supported thereon so that the first line image scans over the wafer surface to locally raise a temperature of the wafer surface to a defect anneal temperature.

2. The system according to claim 1 , wherein the defect anneal temperature is in the range from 650° C. to 1100° C.

3. The system according to claim 1 , wherein the chuck is heated so that it can pre-heat the wafer.

4. The system according to claim 1 , further including a diode-based line-forming optical system that generates a visible light beam that forms at the wafer surface a second line image that at least partially overlaps and scans with the first line image to locally raise the temperature of the wafer surface from the defect annealing temperature to a spike anneal temperature, and wherein the second line image has an intensity variation of within +/−5%.

5. The system according to claim 4 , wherein the spike anneal temperature is in the range from 1150° C. to 1350° C.

6. The system according to claim 4 , wherein the first and second line images have respective first and second widths, and wherein the second width is in the range from 5% to 25% of the first width.

7. The system according to claim 1 , wherein each side peak is defined by a maximum value MX and first and second minimum values m 1 and m 2 , and wherein the second slit aperture is configured to truncate the second intensity profile between the maximum value MX and the second minimum value m 2 in each first side peak.

8. The system according to claim 1 , wherein the relay optical system has substantially 1× magnification in the first direction.

9. The system according to claim 8 , wherein the relay optical system is a cylindrical optical system having optical power only in the first direction.

10. The system according to claim 1 , wherein the optical relay system consists of reflective optical components only.

11. The system according to claim 1 , wherein the first aperture device comprises a pair of blades operably disposed in the object plane.

12. The system of claim 1 , wherein the second aperture device comprises a pair of blades operably disposed in the intermediate focus plane.

13. The system of claim 4 , wherein the diode-based line-forming optical system includes a laser diode light source and line-forming optics arranged relative thereto.

Assignees

• Ultratech Inc

Inventors

• Hawryluk Andrew M
• Anikitchev Serguei

Classifications

• H10P95/90

  Thermal treatments, e.g. annealing or sintering · CPC title

• H10P34/42 Primary

  with electromagnetic radiation, e.g. laser annealing (laser cutting H10P54/20) · CPC title

• H10P72/0436

  mainly by radiation · CPC title

• B23K26/0066

  Operations & Transport · mapped topic

• B23K26/0626

  Energy control of the laser beam (B23K26/0622 takes precedence) · CPC title