Etching process for improving the strength of a laser-machined silicon-based ceramic article

Patent · Tue Jan 01 00:00:00 EST 1991

OSTI ID:867862

Copley, Stephen M ^[1]; Tao, Hongyi ^[2]; Todd-Copley, Judith A ^[1]

---

1. Palos Verdes, CA
2. Covina, CA

A process for improving the strength of laser-machined articles formed of a silicon-based ceramic material such as silicon nitride, in which the laser-machined surface is immersed in an etching solution of hydrofluoric acid and nitric acid for a duration sufficient to remove substantially all of a silicon film residue on the surface but insufficient to allow the solution to unduly attack the grain boundaries of the underlying silicon nitride substrate. This effectively removes the silicon film as a source of cracks that otherwise could propagate downwardly into the silicon nitride substrate and significantly reduce its strength.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• DOE Contract Number: AC05-84OR21400
• Assignee: University of Southern California (Los Angeles, CA)
• Patent Number(s): US 5022957
• OSTI ID: 867862
• Country of Publication: United States
• Language: English

Related Subjects

etching
process
improving
strength
laser-machined
silicon-based
ceramic
article
articles
formed
material
silicon
nitride
surface
immersed
solution
hydrofluoric
acid
nitric
duration
sufficient
remove
substantially
film
residue
insufficient
allow
unduly
attack
grain
boundaries
underlying
substrate
effectively
removes
source
cracks
otherwise
propagate
downwardly
significantly
reduce
significantly reduce
silicon film
hydrofluoric acid
remove substantially
ceramic article
etching process
ceramic material
grain boundaries
silicon nitride
nitric acid
effectively removes
articles formed
based ceramic
silicon-based ceramic
move substantially
ceramic mater
machined surface
effectively remove
/216/65/134/252/