Appeal No. 2002-1029
Application 08/869,328
detected, the end point of polishing has been reached. Yu
teaches several frequency ranges for his disclosed process. On
the one hand, Yu suggests monitoring frequencies in the audible
range (approximately 20 Hz to 20,000 Hz) using a microphone as a
transducer. However, Yu also discloses using acoustic energy
in the non-audible range (less than 20 Hz or greater than
20,000 Hz). See col. 6, lines 48-51; col. 4, lines 48-53. For
frequencies above 20,000 Hz, Yu states that a contact transducer,
such as a piezoelectric transducer, may be used in lieu of the
microphone. Id. Yu does not specifically disclose detecting
acoustic emissions at frequencies above 50,000 Hz.
Salugsugan discloses a similar process. However,
Salugsugan uses low frequencies to signal the end of polishing,
specifying a low band pass filter to attenuate frequencies above
200 Hz by at least 60 db. Consequently, Salugsugan does not
disclose frequencies above 50,000 Hz.
The examiner is of the view that with respect to the
frequency range above 50,000 Hz, “the values of the mechanical
properties are obvious because they are a matter of determining
optimum conditions by routine experimentation. Discovery of [an]
optimum value of [a] result effective variable in [a] known
4
Page: Previous 1 2 3 4 5 6 7 Next
Last modified: November 3, 2007