Removal of material by polarized radiation

• US 5,958,268 A
• Filed: 03/01/1996
• Issued: 09/28/1999
• Est. Priority Date: 06/07/1995
• Status: Expired due to Fees

• Current Assignee: Cauldron Limited Partnership
• Original Assignee: Cauldron Limited Partnership
• Inventors: Parker, William P., Engelsberg, Audrey C.
• Primary Examiner(s): Mills, Gregory L.
• Application Number:
  US08/609,449
• Time in Patent Office: 1,306 Days
• Field of Search: 219/121.68, 219/121.69, 219/121.72, 219/121.84, 219/121.85, 134/1, 134/1.3, 216/65, 216/94, 437/173, 156/643.1, 264/400
• US Class Current: 219/121.84
• CPC Class Codes: B08B 7/0042 by laser
• CPC Class Codes: G03F 7/2022 Multi-step exposure, e.g. hybrid; backside exposure; blanket exposure, e.g. for image reversal; edge exposure, e.g. for edge bead removal; corrective exposure
• CPC Class Codes: G03F 7/42 Stripping or agents therefor
• CPC Class Codes: G03F 7/704 Scanned exposure beam, e.g. raster-, rotary- and vector scanning mask projection exposure involving relative movement of patterned beam and workpiece during imaging G03F7/70358
• CPC Class Codes: G03F 7/70566 Polarisation control
• CPC Class Codes: G03F 7/70866 of mask or workpiece
• CPC Class Codes: G03F 7/70925 Cleaning, i.e. actively freeing apparatus from pollutants, e.g. using plasma cleaning
• CPC Class Codes: H01L 21/32051 Deposition of metallic or metal-silicide layers
• CPC Class Codes: H01L 21/76819 Smoothing of the dielectric planarisation of insulating materials per se H01L21/31051

Abstract

An apparatus and method for selectively removing undesired material from the surface of a substrate provides a flow of inert gas over the undesired material substrate surface while irradiating the undesired material with energetic photons. The invention enables removal of undesired material without altering the physical properties of the material underlying or adjacent the removed, undesired material. Removal effectiveness may be enhanced by utilizing polarized energetic photons. Directing a laser beam to the back side of a transparent substrate may enhance the effectiveness of removal.

Claims

1. A method for selectively removing undesired material from a treatment surface of a substrate without affecting the physical properties of desired material to be left on the treatment surface adjacent to or underlying the undesired material, comprising the step of:

irradiating said undesired material and said desired material with polarized photons in a spatial and temporal concentration at said treatment surface sufficient to release the undesired material from the treatment surface and insufficient to alter the physical properties of the desired material.

2. The method of claim 1, wherein the desired material includes the substrate and a thin film upon the substrate.

3. The method of claim 2, wherein the thin film is selected from the group consisting of hafnium oxide, chrome, indium tin oxide, aluminum and nickel.

4. The method of claim 3, wherein the substrate is selected from the group consisting of quartz, borosilicate glass, silicon, steel and aluminum.

5. The method of claim 4, wherein the thin film is chrome and the substrate is quartz or borosilicate glass.

6. The method of claim 4, wherein the thin film is indium tin oxide and the substrate is quartz or borosilicate glass.

7. The method of claim 4, wherein the thin film is aluminum and the substrate is silicon.

8. The method of claim 4, wherein the thin film is hafnium oxide and the substrate is quartz or borosilicate glass.

9. The method of claim 4, wherein the thin film is nickel and the substrate is steel or aluminum.

10. The method of claim 1, further comprising the step of:

simultaneously introducing across said undesired material a flow of gas substantially inert to said substrate.

11. A method for selectively removing undesired material from a treatment surface of a substrate without affecting the physical properties of desired material to be left on the treatment surface adjacent to or underlying the undesired material, comprising the steps of:

polarizing laser light such that one of the s-component and p-component of the laser light substantially predominates over the other of the s-component and the p-component; and

applying said polarized laser light to said undesired material and said desired material at an energy flux and power flux at said treatment surface sufficient to release the undesired material from the treatment surface and insufficient to alter the physical properties of the desired material.

12. The method of claim 11, wherein said laser light is generated by a pulsed KrF excimer laser.

13. The method of claim 11, further comprising the step of:

simultaneously introducing across said undesired material a flow of gas substantially inert to said substrate.

14. A method for selectively removing undesired material from a treatment surface of a substrate without affecting the physical properties of desired material to be left on the treatment surface adjacent to or underlying the undesired material, comprising the steps of:

irradiating said undesired material and said desired material with polarized photons at energy and power flux levels sufficient to break the internal bonds of the undesired material and insufficient to raise the temperature of the desired material to a level which would produce changes in the physical properties of the desired material.

15. The method of claim 14, further comprising the step of:

simultaneously introducing across said undesired material a flow of gas substantially inert to said substrate.

16. A method for selectively removing undesired material from a treatment surface of a piezoelectric substrate without affecting the physical properties of desired material to be left on the treatment surface adjacent to or underlying the undesired material, comprising the steps of:

polarizing laser light such that the p-component of the laser light substantially predominates over the s-component; and

applying said polarized laser light to said treatment surface of said piezoelectric substrate at an energy flux and power flux sufficient to release the undesired material from the treatment surface and insufficient to alter the physical properties of the desired material.

17. The method of claim 16, wherein said piezoelectric substrate includes at least one of lithium tantalate and lithium niobate.

18. The method of claim 16, further comprising the step of:

simultaneously introducing across said undesired material a flow of gas substantially inert to said piezoelectric substrate.