Apparatus and method of detecting the electroless deposition endpoint

• US 20050088647A1
• Filed: 09/17/2004
• Published: 04/28/2005
• Est. Priority Date: 09/19/2003
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Lopatin, Sergey, Birang, Manoocher, Shanmugasundram, Arulkumar, Pancham, Ian A.
• Granted Patent: US 7,534,298 B2
• Time in Patent Office: Days
• US Class Current: 356/72
• CPC Class Codes: C23C 18/1651 Two or more layers only obtained by electroless plating
• CPC Class Codes: C23C 18/1667 Radiant energy, e.g. laser
• CPC Class Codes: C23C 18/1675 Process conditions
• CPC Class Codes: G01B 11/0683 measurement during deposition or removal of the layer
• CPC Class Codes: G01N 21/8422 Investigating thin films, e.g. matrix isolation method
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10

Abstract

An apparatus and a method of controlling an electroless deposition process by directing electromagnetic radiation towards the surface of a substrate and detecting the change in intensity of the electromagnetic radiation at one or more wavelengths reflected off features on the surface of the substrate. In one embodiment the detected end of an electroless deposition process step is measured while the substrate is moved relative to the detection mechanism. In another embodiment multiple detection points are used to monitor the state of the deposition process across the surface of the substrate. In one embodiment the detection mechanism is immersed in the electroless deposition fluid on the substrate. In one embodiment a controller is used to monitor, store, and/or control the electroless deposition process by use of stored process values, comparison of data collected at different times, and various calculated time dependent data.

Claims

1. An apparatus for monitoring an electroless deposition process comprising:

a chamber;

a substrate support disposed in the chamber having a substrate receiving surface;

an electromagnetic radiation source directed towards the substrate receiving surface;

a detector that detects the intensity of reflected electromagnetic radiation from a surface of a substrate mounted on the substrate receiving surface during an electroless deposition process; and

a controller adapted to receive a signal from the detector and to control the electroless deposition process.

2. The apparatus of claim 1, wherein the electromagnetic radiation source emits electromagnetic radiation at wavelengths between about 200 nanometers and about 800 nanometers.

3. The apparatus of claim 1, wherein the electromagnetic radiation source comprises one or more light emitting diodes.

4. The apparatus of claim 1, wherein the detector comprises two or more detectors.

5. The apparatus of claim 1, further comprising a drive mechanism to move the substrate support relative to the detector.

7. The apparatus of claim 1, wherein the detector is a spectrometer.

8. The apparatus of claim 1, further comprising:

a fiber optic cable which receives the electromagnetic radiation collected from the electromagnetic radiation source;

a mechanical slit that allows the reflected electromagnetic radiation or the electromagnetic radiation from the fiber optic cable to pass to the detector; and

a controller that selectively controls the transmission of the reflected electromagnetic radiation or the electromagnetic radiation from the fiber optic cable to the detector by use of a mechanical actuator that positions the mechanical slit.

9. The apparatus of claim 1, wherein the controller further comprises

a memory attached to the controller to stored the signal data;

and

a control device wherein the controller device is used to control the electroless deposition process based on commands from the controller based on the comparison of the signal data and a process value.

6. An apparatus of claim 6, further comprising a second drive mechanism to move the detector relative to the substrate support.

10. An apparatus for monitoring an electroless deposition process comprising:

a chamber;

a substrate support disposed in the chamber having a substrate receiving surface;

an electromagnetic radiation source directed towards the substrate receiving surface;

a detector that detects the intensity of the reflected electromagnetic radiation from the surface of a substrate mounted on the substrate receiving surface during an electroless deposition process;

a second detector that detects the intensity of the electromagnetic radiation from the electromagnetic radiation source; and

a controller adapted to receive a signal from the detector and a signal from the second detector and to control the electroless deposition process.

11. The apparatus of claim 10, further comprising a fiber optic cable that receives the electromagnetic radiation collected from the electromagnetic radiation source and transmits the signal to the second detector.

12. The apparatus of claim 10, wherein the detector is a spectrometer.

13. The apparatus of claim 10, wherein the electromagnetic radiation source emits electromagnetic radiation at wavelengths between about 200 nanometers and about 800 nanometers.

14. The apparatus of claim 10, wherein the detector comprises two or more detectors.

15. The apparatus of claim 10, further comprising a drive mechanism to can move the substrate support relative to the detector.

16. An apparatus of claim 15, further comprising a second drive mechanism to move the detector relative to the substrate support.

17. The apparatus of claim 10, wherein the second detector is a spectrometer.

18. The apparatus of claim 10, wherein the electromagnetic radiation source is one or more light emitting diodes.

19. An apparatus for monitoring an electroless deposition process comprising:

a chamber;

a substrate support disposed in the chamber having a substrate receiving surface;

a electromagnetic radiation source comprising one or more light emitting diodes directed towards the substrate receiving surface;

a detector that detects the intensity of the reflected electromagnetic radiation from the surface of a substrate mounted on the substrate receiving surface during an electroless deposition process; and

a controller adapted to receive a signal from the detector and processes the signals to determine an initiation of the electroless deposition process.

20. The apparatus of claim 19, further comprising a second detector that detects the intensity of the electromagnetic radiation from the electromagnetic radiation source.

21. The apparatus of claim 19, wherein the controller is further adapted to control the electroless deposition process.

22. A system for monitoring an electroless deposition process comprising:

a chamber;

a substrate support mounted in the chamber having a substrate receiving surface;

an electromagnetic radiation source directed towards the substrate receiving surface;

a detector that detects the intensity of the reflected electromagnetic radiation from the surface of a substrate mounted on the substrate receiving surface during an electroless deposition process;

a controller adapted to receive a signal from the detector and to control the electroless deposition process; and

a memory, coupled to the controller, the memory comprising a computer-readable medium having a computer-readable program embodied therein for directing the operation of the electroless deposition system, the computer-readable program comprising;

computer instructions to control the electroless deposition system to;

(i) start processing;

(ii) collect and store into the memory the intensity of the reflected electromagnetic radiation data during the electroless deposition process;

(iii) compare the stored data with the collected data, then subsequently;

(iv) stop the electroless deposition process when the collected data exceeds a threshold value.

23. The apparatus of claim 22, wherein the threshold value data is stored in the memory.

24. The apparatus of claim 22, wherein the electromagnetic radiation source emits electromagnetic radiation at wavelengths between about 200 nanometers and about 800 nanometers.

25. The apparatus of claim 22, wherein the electromagnetic radiation source is one or more light emitting diodes.

26. The apparatus of claim 22, wherein the detector comprises two or more detectors.

27. The apparatus of claim 22, further comprising a drive mechanism to can move the substrate support relative to the detector.

28. An apparatus of claim 27, further comprising a second drive mechanism to move the detector relative to the substrate support.

29. The apparatus of claim 22, wherein the detector is a spectrometer.

30. The apparatus of claim 22, further comprising a second detector that detects the intensity of the electromagnetic radiation from the electromagnetic radiation source.

31. A method of controlling an electroless deposition process comprising:

positioning a substrate in an electroless deposition chamber;

emitting electromagnetic radiation from a broadband light source onto the substrate;

detecting an intensity of the electromagnetic radiation at one or more wavelengths that is reflected off a surface of a substrate during an electroless deposition process step by use of a detector; and

monitoring the intensity of the electromagnetic radiation at the one or more wavelengths to determine the status of the electroless deposition process.

32. The method of claim 31, wherein detecting an intensity of the electromagnetic radiation during the electroless deposition process further comprises detecting an intensity of the electromagnetic radiation during a first electroless deposition process step and a second electroless deposition process step.

33. The method of claim 31, further comprising rotating the substrate while detecting the intensity of the electromagnetic radiation.

34. The method of claim 31, further comprising moving the detector relative to the substrate.

35. The method of claim 31, wherein the one or more wavelengths is between about 200 nanometers and about 800 nanometers.

36. The method of claim 31, further comprising immersing the detector in an electroless deposition fluid that is in contact with the substrate before detecting the intensity of the electromagnetic radiation.

37. A method of controlling an electroless deposition process comprising:

emitting electromagnetic radiation from a broadband light source;

detecting an intensity of the electromagnetic radiation at one or more wavelengths that is reflected off a surface of a substrate during an electroless deposition process by use of a detector;

comparing the detected electromagnetic radiation intensity at one or more wavelengths at a first time with electromagnetic radiation intensity collected at one or more wavelengths at a second time; and

modifying an electroless deposition process step when the difference between the detected electromagnetic radiation at one or more wavelengths at the first time with the detected electromagnetic radiation at one or more wavelengths at the second time exceeds a process value.

38. The method of claim 37, wherein the stored electromagnetic radiation intensity data which is compared with the detected electromagnetic radiation intensity data is a value selected between about 0 and about 10 seconds after the start of the deposition process.

39. The method of claim 37, further comprising rotating while detecting the intensity of the electromagnetic radiation.

40. The method of claim 37, further comprising moving the detector relative to the substrate.

41. The method of claim 37, wherein detecting an intensity of the electromagnetic radiation during the electroless deposition process comprises detecting an intensity of the electromagnetic radiation during a first electroless deposition process step and a second electroless deposition process step.

42. A method of controlling an electroless deposition process comprising:

emitting electromagnetic radiation from a broadband light source;

detecting an intensity of the electromagnetic radiation at one or more wavelengths that is reflected off a surface of a substrate during an electroless deposition process at a first time;

detecting an intensity of the electromagnetic radiation at one or more wavelengths that is reflected off a surface of a substrate during an electroless deposition process at a second time;

calculating a first rate of change of the intensity at one or more wavelengths using the electromagnetic radiation detected at the first time and the second time;

detecting an intensity of the electromagnetic radiation at one or more wavelengths that is reflected off a surface of a substrate during an electroless deposition process at a third time;

detecting an intensity of the electromagnetic radiation at one or more wavelengths that is reflected off a surface of a substrate during an electroless deposition process at a fourth time;

calculating a second rate of change of the intensity at one or more wavelengths using the electromagnetic radiation detected at the third time and the fourth time;

comparing the calculated rate of change at the first time and the second time; and

modifying the electroless deposition process step when the difference between the rate of change of the intensity at the first time and the second time equals a process value.

43. The method of claim 42, where the electromagnetic radiation data collected at the second time is also the same electromagnetic radiation data collected at the third time.

44. The method of claim 42, wherein the one or more wavelengths is between about 200 nanometers and about 800 nanometers.

45. A method of controlling an electroless deposition process comprising:

emitting electromagnetic radiation from a broadband light source;

detecting an intensity of the electromagnetic radiation at one or more wavelengths from the broadband light source by use of a first detector;

detecting an intensity of the electromagnetic radiation at one or more wavelengths that is reflected off a surface of a substrate during an electroless deposition process by use of a second detector;

calculating a difference in intensity of the detected electromagnetic radiation at the one or more wavelengths by the first detector and the second detector; and

monitoring the calculated difference in intensity at one or more wavelengths over time to determine the status of the electroless deposition process.

46. A method of controlling an electroless deposition process comprising:

delivering an electroless deposition fluid to a substrate in an electroless deposition chamber;

immersing a detector in the electroless deposition fluid in contact with the substrate;

detecting the intensity of the electromagnetic radiation comprising;

emitting electromagnetic radiation from a broadband light source;

detecting an intensity of the electromagnetic radiation at one or more wavelengths reflected off a surface of a substrate;

comparing the detected intensity of the electromagnetic radiation at a first time with a detected intensity of the electromagnetic radiation at a second time;

starting a deposition timer when the difference between the intensity of the electromagnetic radiation at the first time and the intensity of the electromagnetic radiation at the second time equals a process value; and

modifying an electroless deposition process step when after the deposition timer has reached a defined period of time.

47. A method of controlling an electroless deposition process comprising:

emitting electromagnetic radiation from a broadband light source;

detecting an intensity of the electromagnetic radiation at one or more wavelengths reflected off a surface of a substrate during an electroless deposition process at two or more positions on the surface of the substrate;

comparing a detected electromagnetic radiation at a position on the surface of the substrate at a first time with the electromagnetic radiation at a second time; and

modifying an electroless deposition process step when the difference between the electromagnetic radiation at the position on the surface of the substrate at a first time and a second time exceeds a process value.

48. A method of controlling an electroless deposition process comprising:

emitting electromagnetic radiation from a light source;

detecting the intensity of reflected electromagnetic radiation off a surface of a substrate by use of a detector;

scanning the detector across the surface of the substrate;

calculating the average state of the process by summing the monitored intensities at one or more wavelengths over a period of time and dividing the summed results by the period of time; and

modifying an electroless deposition process step when the calculated average intensity equals some process value.

49. A method of controlling an electroless deposition process comprising:

emitting electromagnetic radiation from a light source;

detecting the intensity of reflected electromagnetic radiation off a surface of a substrate at two or more wavelengths;

calculating a difference in intensity of detected electromagnetic radiation intensity values at a first time and a second time at each detected wavelength; and

monitoring the intensity of the electromagnetic radiation at a wavelength that has the largest calculated difference to determine the status of the electroless deposition process.

50. An apparatus for monitoring an electroless deposition process comprising:

a chamber;

a substrate support disposed in the chamber having a substrate receiving surface;

a substrate having a detection feature on a surface, wherein the substrate is disposed on the substrate receiving surface of the substrate support;

an electromagnetic radiation source directed towards the surface of the substrate;

a detector that detects the intensity of reflected electromagnetic radiation from the detection feature during an electroless deposition process; and

a controller adapted to receive a signal from the detector and to control the electroless deposition process.

51. The apparatus of claim 50, wherein the electromagnetic radiation source emits electromagnetic radiation at wavelengths between about 200 nanometers and about 800 nanometers.

52. The apparatus of claim 50, wherein the detection feature is shaped to interact with the electromagnetic radiation reflected from the detection feature as the electroless deposition process progresses.

53. The apparatus of claim 50, wherein the electromagnetic radiation source comprises one or more light emitting diodes.

54. The apparatus of claim 50, wherein the detector comprises two or more detectors.

55. The apparatus of claim 50, further comprising a drive mechanism to move the substrate support relative to the detector.

56. An apparatus of claim 55, further comprising a second drive mechanism to move the detector relative to the substrate support.

57. The apparatus of claim 50, wherein the detector is a spectrometer.

58. The apparatus of claim 50, wherein the detection feature is an array of features spaced between about 100 nanometers and about 100 micrometers apart.

59. A method of controlling an electroless deposition process comprising:

positioning a substrate in an electroless deposition chamber;

emitting electromagnetic radiation from a broadband light source onto a detection feature on the substrate;

detecting an intensity of the electromagnetic radiation at one or more wavelengths that is reflected off the detection feature during an electroless deposition process step by use of a detector; and

monitoring the intensity of the electromagnetic radiation at the one or more wavelengths to determine the status of the electroless deposition process.

60. The method of claim 59, wherein detecting an intensity of the electromagnetic radiation during the electroless deposition process further comprises detecting an intensity of the electromagnetic radiation during a first electroless deposition process step and a second electroless deposition process step.

61. The method of claim 59, further comprising rotating the substrate while detecting the intensity of the electromagnetic radiation.

62. The method of claim 59, further comprising moving the detector relative to the substrate.

63. The method of claim 59, wherein the one or more wavelengths is between about 200 nanometers and about 800 nanometers.

64. The method of claim 59, further comprising immersing the detector in an electroless deposition fluid that is in contact with the substrate before detecting the intensity of the electromagnetic radiation.

65. A method of sensing the initiation of the electroless deposition process comprising:

positioning a substrate in an electroless deposition chamber;

emitting electromagnetic radiation from a broadband light source onto the substrate;

detecting an intensity of the electromagnetic radiation at one or more wavelengths that is reflected off a surface of a substrate at the start of the electroless deposition process by use of a detector;

detecting an intensity of the electromagnetic radiation at one or more wavelengths that is reflected off a surface of a substrate at a second time by use of a detector; and

modifying an electroless deposition process step when the change in the detected intensity at one or more wavelengths exceed a desired level.