Methods and apparatus for cleaning substrates

Patent metadata

Field	Value
Publication number	US-11848217-B2
Application number	US-202117347011-A
Country	US
Kind code	B2
Filing date	Jun 14, 2021
Priority date	Sep 20, 2016
Publication date	Dec 19, 2023
Grant date	Dec 19, 2023

Abstract

The present invention discloses a method for cleaning substrate without damaging patterned structure on the substrate using ultra/mega sonic device, comprising: applying liquid into a space between a substrate and an ultra/mega sonic device; setting an ultra/mega sonic power supply at frequency f 1 and power P 1 to drive said ultra/mega sonic device; after micro jet generated by bubble implosion and before said micro jet generated by bubble implosion damaging patterned structure on the substrate, setting said ultra/mega sonic power supply at frequency f 2 and power P 2 to drive said ultra/mega sonic device; after temperature inside bubble cooling down to a set temperature, setting said ultra/mega sonic power supply at frequency f 1 and power P 1 again; repeating above steps till the substrate being cleaned.

First claim

What is claimed is:

1. An apparatus for cleaning a semiconductor wafer comprising features of patterned structures, the apparatus comprising:
a wafer holder configured to hold the semiconductor wafer;
an inlet configured to apply liquid on the semiconductor wafer;
a transducer configured to deliver acoustic energy to the liquid;
a power supply of the transducer; and
a controller for the power supply comprising a timer, the controller being configured to control the transducer based on the timer to:
deliver acoustic energy to the liquid at a first frequency and a first power level for at least a portion of a predetermined first time period, wherein bubble implosion occurs in the first time period, and
deliver acoustic energy to the liquid at a second frequency and a second power level for at least a portion of a predetermined second time period,
wherein the controller is configured to alternately apply the first and second time periods one after another for a predetermined number of cycles,
wherein the first and second time periods, the first and second power levels, and the first and second frequencies are determined such that no feature is damaged as a result of delivering the acoustic energy; and
wherein the controller is further configured to control bubble implosion under an implosion intensity that would result in damages to the patterned structures by controlling Tn below Td, wherein Tn is a maximum temperature of the bubbles after the predetermined number of cycles, and Td is a temperature of the bubbles that would result in implosion with a high intensity damaging the patterned structures.

2. The apparatus of claim 1 , wherein the wafer holder comprises a rotating chuck.

3. The apparatus of claim 1 , wherein the wafer holder comprises a cassette submerged in a cleaning tank.

4. The apparatus of claim 1 , wherein the inlet comprises a nozzle.

5. The apparatus of claim 1 , wherein the transducer is connected to the inlet and imparts acoustic energy to the liquid flowing through the inlet.

6. The apparatus of claim 1 , wherein the second power level is lower than the first power level.

7. The apparatus of claim 6 , wherein the second power level is zero.

8. The apparatus of claim 1 , wherein the second frequency is higher than the first frequency.

9. The apparatus of claim 1 , wherein acoustic energy in the second time period is in antiphase to acoustic energy in the first time period.

10. The apparatus of claim 1 , wherein the first frequency is equal to the second frequency, while the first power level is higher than the second power level.

11. The apparatus of claim 1 , wherein the first frequency is higher than the second frequency, while the first power level is higher than the second power level.

12. The apparatus of claim 1 , wherein the first frequency is lower than the second frequency, while the first power level is equal to the second power level.

13. The apparatus of claim 1 , wherein the first frequency is lower than the second frequency, while the first power level is higher than the second power level.

14. The apparatus of claim 1 , wherein the first frequency is lower than the second frequency, while the first power is lower than the second power.

15. The apparatus of claim 1 , wherein the acoustic enemy power level rises from the first power level during the first time period.

16. The apparatus of claim 1 , wherein the acoustic energy power level falls from the first power level during the first time period.

17. The apparatus of claim 1 , wherein the acoustic energy power level both rises and falls from the first power level during the first time period.

18. The apparatus of claim 1 , wherein the acoustic energy frequency changes to a lower value from the first frequency during the first time period.

19. The apparatus of claim 1 , wherein the acoustic enemy frequency changes to a higher value from the first frequency during the first time period.

20. The apparatus of claim 1 , wherein the acoustic enemy frequency changes to a higher value from the first frequency and then back to the first frequency during the first time period.

21. The apparatus of claim 1 , wherein the acoustic energy frequency changes to a lower value from the first frequency and then back to the first frequency during the first time period.

22. The apparatus of claim 1 , wherein the acoustic energy frequency changes from the first frequency to a first lower value lower than the first frequency, and then to a second lower value lower than the first lower value, during the first time period.

23. The apparatus of claim 1 , wherein the acoustic enemy frequency changes from the first frequency to a first higher value higher than the first frequency, and then to a second higher value higher than the first higher value.

24. The apparatus of claim 1 , wherein the acoustic energy frequency changes from the first frequency to a first lower value lower than the first frequency, and then to a second lower value higher than the first lower value but lower than the first frequency.

25. The apparatus of claim 1 , wherein the acoustic energy frequency changes from the first frequency to a lower value lower than the first frequency, and then to a higher value higher than the first frequency.

26. The apparatus of claim 1 , wherein the acoustic enemy frequency changes from the first frequency to a higher value higher than the first frequency, and then to a lower value lower than the first frequency.

27. The apparatus of claim 1 , wherein the acoustic energy frequency changes from the first frequency to a first higher value higher than the first frequency, and then to a second higher value higher than the first frequency but lower than the first higher value.

28. The apparatus of claim 1 , wherein the second frequency is zero and the second power level remains a constant positive value during the second time period.

29. The apparatus of claim 1 , wherein the second frequency is zero and the second power level remains a constant negative value during the second time period.

30. The apparatus of claim 1 , wherein the features comprise vias or trenches having depth to width ratios of at least 3.

31. The apparatus of claim 1 , wherein a device manufacturing node of the semiconductor wafer is no more than 16 nanometers.

32. The apparatus of claim 1 , wherein the wafer holder is further configured to rotate the wafer with respect to the transducer as acoustic energy is delivered.

33. The apparatus of claim 1 , wherein the features are not damaged by expansion of bubbles in the first time period.

34. The apparatus of claim 1 , wherein temperatures inside bubbles decrease in the second time period.

35. The apparatus of claim 34 , wherein temperatures inside the bubble decrease to near a temperature of said liquid in the second time period.

36. The apparatus of claim 1 , wherein the first time period is shorter than 2,000 times of a cycle period of the first frequency.

37. The apparatus of claim 1 , wherein the first time period is shorter than ((T i −T 0 −ΔT)/(ΔT−δT)+1)/f 1 , where T i is an implosion temperature, T 0 is a temperature of the liquid, ΔT is a temperature increase after one time of compressi

Assignees

• Acm Research Shanghai Inc

Inventors

• Wang Hui
• Wang Xi
• Chen Fuping
• Chen Fufa
• Wang Jian
• Zhang Xiaoyan
• Jin Yinuo
• Jia Zhaowei
• Wang Jun
• Li Xuejun

Classifications

• H10P72/0604 Primary

  Process monitoring, e.g. flow or thickness monitoring · CPC title

• H10P72/0416

  with the semiconductor substrates being dipped in baths or vessels · CPC title

• H10P72/76

  using mechanical means, e.g. clamps or pinches · CPC title

• H10P72/50

  for positioning, orientation or alignment · CPC title

• H10P70/27

  during, before or after processing of conductive materials, e.g. polysilicon or amorphous silicon layers · CPC title