Electron beam-induced etching

Patent metadata

Field	Value
Publication number	US-10304658-B2
Application number	US-201514802648-A
Country	US
Kind code	B2
Filing date	Jul 17, 2015
Priority date	Jun 10, 2013
Publication date	May 28, 2019
Grant date	May 28, 2019

Abstract

Beam-induced etching uses a work piece maintained at a temperature near the boiling point of a precursor material, but the temperature is sufficiently high to desorb reaction byproducts. In one embodiment, NF 3 is used as a precursor gas for electron-beam induced etching of silicon at a temperature below room temperature.

First claim

We claim as follows:

1. A method of forming an image of a work piece, comprising:
flooding an environment surrounding the work piece with a gas containing molecules of NF 3 ;
cooling the work piece to below room temperature;
directing an electron beam toward the work piece, the impact of the electron beam causing the emission of secondary electrons from the work piece into the gas;
causing a cascade ionization of the gas by accelerating the secondary electrons in the gas, wherein the cascade ionization of the gas amplifies the secondary electron signal;
detecting the amplified secondary electron signal; and
forming an image of the work piece using the amplified secondary electron signal.

2. The method of claim 1 in which the work piece comprises silicon.

3. The method of claim 2 , wherein the work piece comprises SiO 2 .

4. The method of claim 1 in which the work piece comprises boron, carbon, silicon, germanium, arsenic, phosphorus, tin, antimony, selenium, or sulphur.

5. A method of processing a silicon-containing work piece, the method comprising:
monitoring a work piece comprising silicon according to the method of claim 1 while carrying out charged particle beam-induced etching on the work piece,
wherein the gas containing the NF 3 molecules functions as an etch precursor gas for the charged particle beam-induced etching.

6. The method of claim 5 , wherein the work piece comprises SiO 2 .

7. A method of forming an image of a work piece, comprising:
cooling the work piece to a temperature below 100° C.
directing an electron beam toward the work piece, the impact of the electron beam causing the emission of secondary electrons;
accelerating the secondary electrons in a gas containing NF 3 to cause an ionization cascade to amplify the secondary electron signal;
detecting the amplified secondary electron signal; and
forming an image of the work piece using the amplified secondary electron signal.

8. The method of claim 7 in which the work piece comprises silicon.

9. The method of claim 7 in which the work piece comprises boron, carbon, silicon, germanium, arsenic, phosphorus, tin, antimony, selenium, or sulphur.

Assignees

• Fei Co

Inventors

• Martin Aiden
• Toth Milos

Classifications

• H10P95/70

  Chemical treatments · CPC title

• H10P52/00

  Grinding, lapping or polishing of wafers, substrates or parts of devices · CPC title

• H10P50/242

  of Group IV materials · CPC title

• H10P50/20

  Dry etching; Plasma etching; Reactive-ion etching · CPC title

• H01J2237/31749

  Focused ion beam · CPC title