Methods for retaining a processing liquid on a surface of a semiconductor substrate
Improved puddle processes and methods are provided herein for retaining a processing liquid on a surface of a semiconductor substrate. More specifically, improved methods are provided herein for retaining a puddle within a center region of a semiconductor substrate while the substrate is stationary, or rotating at relatively low rotational speeds. In the disclosed embodiments, a puddle is retained within a center region of the semiconductor substrate by a thin film, which is deposited within a peripheral edge region of the substrate before a processing liquid is dispensed within the center region of the substrate to form the puddle.
1. A method for retaining a processing liquid on a surface of a semiconductor substrate, the method comprising:
receiving the semiconductor substrate on a spin chuck, the semiconductor substrate having a frontside surface, a backside surface, a side edge surface, a peripheral edge region and a center region, wherein the peripheral edge region includes: (i) the side edge surface, (ii) an annular portion of the frontside surface adjacent to the side edge surface, and (iii) an annular portion of the backside surface adjacent to the side edge surface, and wherein the center region extends from a center of the semiconductor substrate to the peripheral edge region;
depositing a film on the semiconductor substrate, wherein the film is deposited only within the peripheral edge region, and not within the center region, of the semiconductor substrate, wherein the film coats an entirety of the peripheral edge region, including the side edge surface and the annular portions of the frontside surface and the backside surface of the semiconductor substrate, and wherein the film has a lower surface energy than a surface energy of the surface of the semiconductor substrate; and
dispensing the processing liquid on the semiconductor substrate after depositing the film, wherein the processing liquid is dispensed within the center region of the semiconductor substrate to form a puddle of the processing liquid within the center region, and wherein the lower surface energy of the film repels the processing liquid away from the peripheral edge region of the semiconductor substrate to retain the puddle of the processing liquid within the center region of the semiconductor substrate.
2. The method of claim 1 , wherein said depositing the film comprises using a spin-on process to coat the entirety of the peripheral edge region with the film, including the side edge surface and the annular portions of the frontside surface and the backside surface of the semiconductor substrate.
3. The method of claim 1 , wherein said depositing the film comprises depositing the film within the peripheral edge region of the semiconductor substrate while the semiconductor substrate is spinning at a first rotational speed, and wherein said dispensing the processing liquid comprises dispensing the processing liquid within the center region of the semiconductor substrate while the semiconductor substrate is stationary or spinning at a second rotational speed, which is less than the first rotational speed, to form the puddle of the processing liquid within the center region.
4. The method of claim 1 , wherein said depositing the film comprises depositing a material within the peripheral edge region of the semiconductor substrate that is not etched or dissolved by the processing liquid.
5. The method of claim 1 , wherein said dispensing the processing liquid is performed within a first processing chamber, and wherein the method further comprises:
transferring the semiconductor substrate from the first processing chamber to a second processing chamber after dispensing the processing liquid on the semiconductor substrate;
wherein said depositing the film on the semiconductor substrate retains the puddle of the processing liquid within the center region of the semiconductor substrate during said transferring.
6. The method of claim 3 , wherein the first rotational speed is selected from a first range consisting of 200 to 3000 rotations per minute (RPM) and the second rotational speed is selected from a second range consisting of 0 to 50 RPM.
7. The method of claim 4 , wherein said depositing the film comprises depositing a fluoropolymer material, a spin-on carbon (SOC) material, a spin-on silicon carbide (SiC) material or a spin-on self-aligned monolayer (SAM) within the peripheral edge region of the semiconductor substrate.
8. The method of claim 4 , wherein said dispensing the processing liquid comprises dispensing a cleaning solvent, a rinsing solvent, a drying solvent, a developer solvent or an etchant chemical within the center region of the semiconductor substrate.
9. The method of claim 4 , wherein said depositing the film is performed within a processing chamber comprising a frontside bevel nozzle, and wherein said depositing the film comprises:
using the frontside bevel nozzle to deposit the material onto the annular portion of the frontside surface while spinning the semiconductor substrate at a rotational speed, which causes the deposited material to wrap around the side edge surface of the semiconductor substrate to coat the annular portion of the backside surface.
10. The method of claim 4 , wherein said depositing the film is performed within a processing chamber comprising a backside bevel nozzle, and wherein said depositing the film comprises:
using the backside bevel nozzle to deposit the material onto the annular portion of the backside surface while spinning the semiconductor substrate at a rotational speed, which causes the deposited material to wrap around the side edge surface of the semiconductor substrate to coat the annular portion of the frontside surface.
11. The method of claim 4 , wherein said depositing the film is performed within a processing chamber comprising a backside nozzle, and wherein said depositing the film comprises:
using the backside nozzle to deposit the material onto the backside of the semiconductor substrate near the center of the semiconductor substrate while spinning the semiconductor substrate at a rotational speed, which causes the deposited material to cover the backside surface and wrap around the side edge surface of the semiconductor substrate to coat the annular portion of the frontside surface.
12. A method for cleaning a surface of a semiconductor substrate, the method comprising:
receiving the semiconductor substrate on a spin chuck, the semiconductor substrate having a frontside surface, a backside surface, a side edge surface, a peripheral edge region and a center region, wherein the peripheral edge region includes: (i) the side edge surface, (ii) an annular portion of the frontside surface adjacent to the side edge surface, and (iii) an annular portion of the backside surface adjacent to the side edge surface, and wherein the center region extends from a center of the semiconductor substrate to the peripheral edge region;
depositing a film on the semiconductor substrate, wherein the film is deposited only within the peripheral edge region, and not within the center region, of the semiconductor substrate, wherein the film coats an entirety of the peripheral edge region, including the side edge surface and the annular portions of the frontside surface and the backside surface of the semiconductor substrate, and wherein the film has a lower surface energy than a surface energy of the surface of the semiconductor substrate;
dispensing a cleaning solvent on the semiconductor substrate after depositing the film, wherein the cleaning solvent is dispensed within the center region of the semiconductor substrate for a first period of time while the semiconductor substrate is spinning; and
dispensing the cleaning solvent within the center region of the semiconductor substrate for a second period of time while the semiconductor substrate is stationary to form a puddle of the cleaning solvent within the center region, wherein the lower surface energy of the film repels the cleaning solvent away from the peripheral edge region of the semiconductor substrate to retain the puddle of the cleaning solvent within the center region of the semiconductor substrate.
13. The method of claim 12 , wherein said depositing the film comprises using a spin-on process to coat the entirety of the peripheral edge region with the film, including the side edge surface and the annular portions of the frontside surface and the backside surface of the semiconductor substrate.
14. The method of claim 12 , wherein said depositing the film comprises depositing a fluoropolymer material, a spin-on carbon (SOC) material, a spin-on silicon carbide (SiC) material or a spin-on self-aligned monolayer (SAM) within the peripheral edge region of the semiconductor substrate.
15. The method of claim 12 , wherein after dispensing the cleaning solvent within the center region of the semiconductor substrate for the second period of time, the method further comprises:
dispensing the cleaning solvent within the center region of the semiconductor substrate for a third period of time while the semiconductor substrate is spinning;
rinsing the semiconductor substrate with a rinse solvent to remove the cleaning solvent from the semiconductor substrate; and
spinning the semiconductor substrate to dry the semiconductor substrate.
16. A method for cleaning a surface of a semiconductor substrate, the method comprising:
receiving the semiconductor substrate on a spin chuck, the semiconductor substrate having a frontside surface, a backside surface, a side edge surface, a peripheral edge region and a center region, wherein the peripheral edge region includes the side edge surface and annular portions of the frontside surface and the backside surface adjacent to the side edge surface, and wherein the center region extends from a center of the semiconductor substrate to the peripheral edge region;
depositing a film on the semiconductor substrate, wherein the film is deposited only within the peripheral edge region, and not within the center region, of the semiconductor substrate, wherein the film has a lower surface energy than a surface energy of the surface of the semiconductor substrate;
dispensing a first solvent on the semiconductor substrate after depositing the film, wherein the first solvent is dispensed within the center region of the semiconductor substrate while the semiconductor substrate is spinning to clean the semiconductor substrate;
dispensing a second solvent on the semiconductor substrate after dispensing the first solvent, wherein the second solvent is dispensed within the center region of the semiconductor substrate while the semiconductor substrate is spinning to remove the first solvent from the semiconductor substrate;
dispensing a third solvent on the semiconductor substrate after dispensing the second solvent, wherein the third solvent is dispensed within the center region of the semiconductor substrate while the semiconductor substrate is stationary to form a puddle of the third solvent within the center region, wherein said dispensing the first solvent, said dispensing the second solvent and said dispensing the third solvent are performed within a first processing chamber; and
transferring the semiconductor substrate from the first processing chamber to a second processing chamber after dispensing the third solvent on the semiconductor substrate to form the puddle of the third solvent within the center region;
wherein the lower surface energy of the film repels the third solvent away from the peripheral edge region of the semiconductor substrate to retain the puddle of the third solvent within the center region of the semiconductor substrate while the semiconductor substrate is stationary and during said transferring.
17. The method of claim 16 , wherein said depositing the film comprises using a spin-on process to coat an entirety of the peripheral edge region with the film, including the side edge surface and the annular portions of the frontside surface and the backside surface of the semiconductor substrate.
18. The method of claim 16 , wherein the first solvent is a cleaning solvent, wherein the second solvent is a rinse solvent, and wherein the third solvent is a drying solvent.
19. The method of claim 16 , wherein said first processing chamber is a cleaning chamber, wherein said second processing chamber is a supercritical processing chamber, and wherein the method further comprises:
treating the semiconductor substrate with supercritical carbon dioxide (CO 2 ); and
drying the semiconductor substrate.
20. A method for retaining a processing liquid on a surface of a semiconductor substrate, the method comprising:
receiving the semiconductor substrate on a spin chuck, the semiconductor substrate having a frontside surface, a backside surface, a side edge surface, a peripheral edge region and a center region, wherein the peripheral edge region includes the side edge surface and annular portions of the frontside surface and the backside surface adjacent to the side edge surface, and wherein the center region extends from a center of the semiconductor substrate to the peripheral edge region;
depositing a film on the backside surface of the semiconductor substrate, wherein the film coats at least a portion of the backside surface and wraps around the side edge surface of the semiconductor substrate to coat the annular portion of the frontside surface, and wherein the film has a lower surface energy than a surface energy of the surface of the semiconductor substrate; and
dispensing the processing liquid on at least one of the frontside surface and the backside surface of the semiconductor substrate after depositing the film, wherein the processing liquid is dispensed within the center region of the semiconductor substrate to form a puddle of the processing liquid within the center region, and wherein the lower surface energy of the film repels the processing liquid away from the peripheral edge region of the semiconductor substrate to retain the puddle of the processing liquid within the center region of the semiconductor substrate.
21. The method of claim 20 , wherein said depositing the film is performed within a processing chamber comprising a backside bevel nozzle, and wherein said depositing the film comprises:
using the backside bevel nozzle to deposit a liquid material onto the annular portion of the backside surface while spinning the semiconductor substrate at a rotational speed, which causes the deposited liquid material to wrap around the side edge surface of the semiconductor substrate to coat the annular portion of the frontside surface.
22. The method of claim 20 , wherein said depositing the film is performed within a processing chamber comprising a backside nozzle, and wherein said depositing the film comprises:
using the backside nozzle to deposit a liquid material onto the backside of the semiconductor substrate near the center of the semiconductor substrate while spinning the semiconductor substrate at a rotational speed, which causes the deposited liquid material to cover the backside surface and wrap around the side edge surface of the semiconductor substrate to coat the annular portion of the frontside surface.