Semiconductor manufacturing using optical ablation
View Patent ↗The present invention relates to methods and systems for ablation based material removal configuration for use in semiconductor manufacturing that includes the steps of generating an initial wavelength-swept-with-time optical pulse in an optical pulse generator, amplifying the initial pulse, compressing the amplified pulse to a duration of less than about 10 picoseconds and applying the compressed optical pulse to the wafer surface, to remove material from, e.g., wafer surface.
1. A method of removing material from a surface of a semiconductor wafer comprising the steps of:
generating an initial wavelength-swept-with-time optical pulse in an optical pulse generator;
amplifying the initial pulse;
compressing the amplified pulse to a duration of less than about 10 picoseconds, to generate a compressed optical pulse; and
applying the compressed optical pulse to the wafer surface, to remove material from the wafer surface;
wherein the step of amplifying is done with a fiber-amplifier and the step of compressing is done with an air-path between gratings compressor, and the initial wavelength-swept-with-time optical pulses is between about 10 picoseconds and about 3 nanoseconds and the compressed optical pulse has a sub-picosecond duration and an energy density on the surface is between about 2 and about 10 times an optical ablation threshold of the surface.
2. The method of claim 1 , wherein the material removal is done in a line to give minimal-pressure ablation scribing, wherein stress-increasing scratching of the surface is reduced.
3. The method of claim 1 , further comprising a step of sensing a composition of material being removed.
4. The method of claim 1 , wherein the fiber amplifier is an erbium-doped fiber amplifier.
5. The method of claim 1 , wherein the air-path between gratings compressor is a Treacy grating compressor.
6. The method of claim 1 , wherein the compressing is done with a chirped fiber compressor.
7. A method of removing material from a surface of a semiconductor wafer comprising the steps of:
generating an initial wavelength-swept-with-time optical pulse in an optical pulse generator;
amplifying the initial pulse;
compressing the amplified pulse to a duration of less than about 10 picoseconds, to generate a compressed optical pulse; and
applying the compressed optical pulse to the wafer surface, to remove material from the wafer surface;
wherein pulse energy density and ablation rate are independently controlled.
8. The method of claim 7 , wherein the wafer has a silicon, GaAs, or InP substrate.
9. The method of claim 7 , wherein the amplifying is done with one or more fiber-amplifier, one or more semiconductor optical amplifier or combinations thereof.
10. The method of claim 7 , wherein the material removal is used to replace a dry-etching step.
11. The method of claim 7 , wherein the step of amplifying uses one or more optical amplifiers in a train mode.
12. The method of claim 7 , wherein the compressed optical pulse is generally circular with an area of between about 1 and 50 micron in diameter when applied to the surface.
13. The method of claim 7 , wherein two or more fiber amplifiers are used in a train mode and two or more fiber amplifiers are used with one compressor.
14. The method of claim 7 , wherein the compressed optical pulse is scanned on the wafer surface using one or more piezoelectrically driven mirror.
15. The method of claim 7 , wherein the material removal is done in a line to give ablation trench digging.
16. The method of claim 7 , wherein the material includes copper or a noble metal.
17. The method of claim 7 , further comprising a step of sensing a composition of material being removed.
18. The method of claim 17 , wherein a composition of material being sensed is analyzed to determine when the material removal reaches an indication layer.
19. A method of removing material from a surface of a semiconductor wafer comprising the steps of:
generating an initial wavelength-swept-with-time optical pulse in an optical pulse generator;
amplifying the initial pulse;
compressing the amplified pulse to a duration of less than about 10 picoseconds, to generate a compressed optical pulse; and
applying the compressed optical pulse to the wafer surface, to remove material from the wafer surface;
wherein a pulse energy density, a fiber amplifier operating temperature and an ablation rate are independently controlled.