Femtosecond Laser-Induced Formation Of Submicrometer Spikes On A Semiconductor Substrate

Patent metadata

Field	Value
Publication number	US-2016005608-A1
Application number	US-201514836609-A
Country	US
Kind code	A1
Filing date	Aug 26, 2015
Priority date	Sep 24, 2004
Publication date	Jan 7, 2016
Grant date	—

Abstract

The present invention generally provides semiconductor substrates having submicron-sized surface features generated by irradiating the surface with ultra short laser pulses. In one aspect, a method of processing a semiconductor substrate is disclosed that includes placing at least a portion of a surface of the substrate in contact with a fluid, and exposing that surface portion to one or more femtosecond pulses so as to modify the topography of that portion. The modification can include, e.g., generating a plurality of submicron-sized spikes in an upper layer of the surface.

First claim

1 - 47 . (canceled)

48 . A method for processing a substrate, comprising:
disposing a solid substance on a surface of a substrate, placing said surface in contact with a fluid, irradiating said surface of the substrate with a plurality of laser pulses having a pulse width in a range of about 50 femtoseconds to a few nanoseconds so as to generate inclusions comprising at least one constituent of said solid substance within an upper layer of the substrate.

49 . The method of claim 48 , wherein said laser pulses have a pulse width in a range of about 50 femtoseconds to about 500 femtoseconds.

50 . The method of claim 48 , wherein said solid substance comprises an electron donating constituent.

51 . The method of claim 50 , wherein said electron-donating constituent comprises a sulfur-containing substance such that said inclusions comprise sulfur.

52 . The method of claim 48 , wherein said solid substance comprises sulfur powder.

53 . The method of claim 48 , wherein the fluid is a liquid.

54 . The method of claim 53 , wherein said liquid comprises an aqueous solution.

55 . The method of claim 53 , wherein said liquid comprises any of water, alcohol, sulfuric acid and silicon oil.

56 . The method of claim 48 , wherein said substrate comprises a semiconductor substrate.

57 . The method of claim 56 , wherein said semiconductor substrate is any of a doped and undoped silicon wafer.

58 . The method of claim 48 , wherein said laser pulses have a wavelength of less than about 800 nm.

59 . The method of claim 48 , wherein said upper layer has a thickness in a range of about 100 nm to a about 1 micrometer.

60 . The method of claim 48 , wherein a number of the laser pulses applied to each surface location is in a range of 1 to about 2500.

61 . The method of claim 48 , wherein said step of placing said surface in contact with a liquid comprises disposing a layer of a liquid having a thickness in a range of about 1 mm to about 20 mm on said surface.

62 . The method of claim 48 , wherein said laser pulses have an energy in a range of about 10 microjoules to about 400 microjoules.

Assignees

• Harvard College

Inventors

• Mazur Eric
• Shen Mengyan

Classifications

• H10P72/0422

  for wet etching · CPC title

• H10P50/00

  Etching of wafers, substrates or parts of devices · CPC title

• H10P32/1404

  using predeposition followed by drive-in of impurities into the semiconductor surface, e.g. predeposition from a gaseous phase · CPC title

• H10P32/171

  being group IV material · CPC title

• H10P14/3816

  Pulsed laser beam · CPC title