High-precision feedback control for ion sculpting of solid state features

• US 20050126905A1
• Filed: 10/07/2004
• Published: 06/16/2005
• Est. Priority Date: 06/22/1999
• Status: Abandoned Application

• Current Assignee: Agilent Technologies, Inc., President and Fellows of Harvard College (Harvard Corporation)
• Original Assignee: Agilent Technologies, Inc., President and Fellows of Harvard College (Harvard Corporation)
• Inventors: Flory, Curt, Golovchenko, Jene A., Stein, Derek M., Pittaro, Richard J., Yefchak, George E.
• Application Number:
  US10/960,176
• Publication Number:
  US 20050126905A1
• Time in Patent Office: Days
• US Class Current: 204/192.340
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: B24B 37/013 Devices or means for detecting lapping completion
• CPC Class Codes: B81C 99/004 during manufacturing
• CPC Class Codes: B81C 99/0065 Process control; Yield prediction
• CPC Class Codes: G01N 33/48721 Investigating individual macromolecules, e.g. by translocation through nanopores Coulter counters in general G01N15/12; fabrication methods for nanoscale apertures B81B1/00; sequencing of nucleic acids C12Q1/68
• CPC Class Codes: H01L 22/26 Acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection, in-situ thickness measurement endpoint detection arrangements in CMP apparatus B24B37/013, in discharge apparatus H01J37/32
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

The invention provides a method for controlled fabrication of a solid state structural feature. In the method, a solid state structure is provided and the structure is exposed to an ion beam, under fabrication process conditions for producing the structural feature. A physical detection species is directed toward a designated structure location, and the rate at which the detection species proceeds from the designated structure location is measured. Detection species rate measurements are fit to a mathematical model, and the fabrication process conditions are controlled, based on the fitted detection species rate measurements, to fabricate the structural feature.

Claims

1. A method for controlled fabrication of a solid state structural feature, comprising:

providing a solid state structure;

exposing the structure to an ion beam under fabrication process conditions for producing the structural feature;

directing a physical detection species toward a designated structure location;

measuring a rate at which the detection species proceeds from the designated structure location;

fitting detection species rate measurements to a mathematical model; and

controlling the fabrication process conditions based on the fitted detection species rate measurements to fabricate the structural feature.

2. The method of claim 1 wherein measuring detection species rate comprises making a measurement of count of the species as the species proceeds from the designated structure location.

3. The method of claim 1 further comprising storing detection species rate measurements.

4. The method of claim 1 further comprising adjusting the mathematical model based on the fitted detection species rate measurements.

5. The method of claim 1 wherein fitting detection species rate measurements comprises fitting a selected number of previously acquired detection species rate measurements.

6. The method of claim 1 wherein the mathematical model includes parameters reflecting characteristics of the fabrication process.

7. The method of claim 1 wherein the mathematical model is a polynomial expression.

8. The method of claim 1 wherein the mathematical model is a statistical average of previously acquired detection species rate measurements.

9. The method of claim 1 wherein controlling the fabrication process conditions is based on determining if a preselected detection species rate has been met.

10. The method of claim 9 wherein if a preselected detection species rate has been met, then the ion exposure is continued without further measurement of detection species rates.

11. The method of claim 9 wherein if a preselected detection species rate has been met, then the fabrication process conditions are adjusted to complete the structural feature fabrication.

12. The method of claim 1 wherein controlling the fabrication process conditions is based on determining if measurement of detection species rates is to be continued.

13. The method of claim 1 wherein controlling the fabrication process conditions is carried out during the ion exposure.

14. The method of claim 1 wherein the ion exposure comprises periodic ion exposure with a duty cycle of an ion packet duration and a nonexposure duration.

15. The method of claim 14 wherein controlling the fabrication process conditions comprises controlling ion packet duration.

16. The method of claim 14 wherein controlling the fabrication process conditions comprises controlling ion exposure duty cycle.

17. The method of claim 1 wherein controlling the fabrication process conditions comprises controlling ion energy.

18. The method of claim 1 wherein controlling the fabrication process conditions comprises controlling ion species.

19. The method of claim 1 wherein controlling the fabrication process conditions comprises controlling structure temperature.

20. The method of claim 1 wherein controlling the fabrication process conditions comprises controlling process pressure.

21. The method of claim 1 wherein controlling the fabrication process conditions comprises terminating exposure of the structure to the ion beam at a time when the fitted detection species rate measurements indicate completion of the structural feature fabrication.

22. The method of claim 1 wherein the physical detection species comprises ions.

23. The method of claim 1 wherein the structure comprises a semiconductor substrate.

24. The method of claim 1 wherein the structure comprises a membrane.

25. The method of claim 1 wherein the structure comprises a substrate including a layer in which the structural feature is to be fabricated.

26. The method of claim 1 wherein the structural feature is an aperture in the structure and the designated structure location is through the aperture.

27. The method of claim 26 wherein the aperture comprises an array of apertures.

28. The method of claim 26 wherein the fabrication process conditions are selected to reduce an initial aperture diameter.

29. The method of claim 26 wherein the fabrication process conditions are selected to increase an initial aperture diameter.

30. The method of claim 26 wherein the fabrication process conditions are selected to etch the aperture in the structure.

31. The method of claim 1 wherein the structural feature is a gap between at least two structural edges and the designated structure location is through the aperture.

32. The method of claim 31 wherein the fabrication process conditions are selected to reduce an initial gap in the structure.

33. The method of claim 31 wherein the fabrication process conditions are selected to increase an initial gap in the structure.

34. The method of claim 1 wherein the physical detection species is directed toward a designated structure location during ion beam exposure of the structure.

35. The method of claim 1 wherein the physical detection species is directed toward a designated structure location at a time when the structure is not exposed to the ion beam.