Substrate process tank with acoustical source transmission and method of processing substrates
View Patent ↗A system and method for improving the efficiency and effectiveness of the transmission of acoustical energy to process fluids during substrate processing, such as cleaning or photoresist stripping. The invention utilizes a layered stack of materials to transmit acoustical energy from a source of acoustical energy to the process fluid. The material of which each layer is constructed is chosen so as to reduce the differences in acoustical impedance between consecutive layers of the stack, providing a more gradual transition, in terms of acoustical impedance, when acoustical energy is being transmitted from the source to the process fluid. In one aspect, the invention is a system comprising: a process chamber for receiving a process fluid; an acoustical energy source; and an acoustical stack having a first transmission layer and a second transmission layer that forms an acoustical energy pathway from the acoustical energy source to the process fluid in the process chamber.
1. A system for processing at least one substrate comprising:
a process chamber for receiving a process fluid;
an acoustical energy source;
an acoustical stack for transmitting acoustical energy from the acoustical energy source to process fluid in the process chamber, the acoustical stack comprising three or more consecutive transmission layers including a first transmission layer in contact with the acoustical energy source and a last transmission layer in contact with process fluid in the process chamber;
wherein from the first transmission layer to the last transmission layer, each transmission layer in the acoustical stack has an acoustical impedance value that is less than an acoustical impedance value of a consecutively preceding transmission layer.
2. The system of claim 1 wherein the first transmission layer is made of aluminum, titanium, or beryllium.
3. The system of claim 1 wherein the number of consecutive transmission layers in the acoustical stack is three, including a second transmission layer consecutively located between the first transmission layer and the last transmission layer.
4. The system of claim 3 wherein the second transmission layer is a rigid plate for mounting the acoustical stack to the process chamber.
5. The system of claim 3 wherein the first transmission layer is made of aluminum, titanium, or beryllium, the second transmission layer is made of quartz, the last transmission layer is made of PCTFE, ECTFE, PVDF, FEP, or PFA and the acoustical energy source comprise piezoelectric crystals.
6. The system of claim 1 the process fluid having an acoustical impedance value less than the acoustical impedance value of the last transmission layer.
7. The system of claim 6 wherein the acoustical impedance value of the process fluid is in the range of approximately 0.8 to 2.5 Mrayl.
8. The system of claim 1 wherein the acoustical energy source has an acoustical impedance value that is less than the acoustical impedance value of the first transmission layer.
9. The system of claim 1 wherein the acoustical energy source has an acoustical impedance value that is greater than the acoustical impedance value of the first transmission layer.
10. The system of claim 1 wherein the first transmission layer is made of aluminum, titanium, or beryllium.
11. The system of claim 3 wherein the second transmission layer is made of quartz.
12. The system of claim 1 wherein the last transmission layer is made of PCTFE, ECTFE, PVDF, FEP, or PFA.
13. A method of processing a substrate comprising:
providing a system comprising a process chamber, an acoustical energy source, an acoustical stack forming an acoustical energy pathway from the acoustical energy source to a process fluid in the process chamber, the acoustical stack comprising three or more consecutive transmission layers including a first transmission layer in contact with the acoustical energy source and a last transmission layer in contact with the process fluid in the process chamber, wherein from the first transmission layer to the last transmission layer, each transmission layer in the acoustical stack has an acoustical impedance value that is less than an acoustical impedance value of a consecutively preceding transmission layer;
contacting a substrate with the process fluid;
creating acoustical energy with the acoustical energy source; and
transmitting the acoustical energy to the process fluid via the acoustical stack.
14. The method of claim 13 wherein the first transmission layer is made of aluminum, titanium, or beryllium.
15. The method of claim 13 wherein the number of consecutive transmission layers in the acoustical stack is three, including a second transmission layer consecutively located between the first transmission layer and the last transmission layer.
16. The method of claim 15 wherein the second transmission layer is a rigid plate for mounting the acoustical stack to the process chamber.
17. The method of claim 15 wherein the first transmission layer is made of aluminum, titanium, or beryllium, the second transmission layer is made of quartz, the last transmission layer is made of PCTFE, ECTFE, PVDF, or PFA and the acoustical energy source comprise piezoelectric crystals.
18. The method of claim 17 wherein the process fluid has an acoustical impedance value less than the acoustical impedance value of the last transmission layer.
19. The method of claim 18 wherein the acoustical impedance value of the process fluid is in the range of approximately 0.8 to 2.5 Mrayl.
20. The method of claim 13 wherein the process fluid comprises DI-water and the method further comprises removing contaminants from the substrate.
21. The method of claim 13 wherein the process fluid comprises ozone and the method further comprises stripping photoresist from the substrate.
22. The method of claim 13 wherein the acoustical energy source has an acoustical impedance value that is less than the acoustical impedance value of the first transmission layer.
23. The method of claim 13 wherein the acoustical energy source has an acoustical impedance value that is greater than the acoustical impedance value of the first transmission layer.
24. The method of claim 13 wherein the first transmission layer is made of aluminum, titanium, or beryllium.
25. The method of claim 15 wherein the second transmission layer is made of quartz.
26. The method of claim 13 wherein the last transmission layer is made of PCTFE, ECTFE, PVDF, FEP, or PFA.
27. The method of claim 13 wherein the contacting step comprises submerging the substrate in the process fluid.