Appeal No. 1997-0547
Application No. 08/020,443
including the steps of:
providing a melt of material in a crucible heated by a
heater supplied by a power input;
bringing a seed crystal into contact with the melt;
providing a rate of relative rotation between the seed
crystal and the melt; and
withdrawing the seed from said melt at a pull rate so
that a crystal grows from the seed crystal, wherein during
said withdrawing step there are included the additional steps
of:
perturbing at least one of said power input to said
heater, a rate of seed withdrawal, a rate of relative rotation
between crucible and seed, and an applied magnetic field;
weighing one of the growing crystal and the melt to
provide a weight signal indicative of the weight of the
growing crystal; and
providing a feedback loop using signal processing of the
weight signal to control said at least one of said power
input, said pull rate, said rate of relative rotation and said
magnetic field to control crystal diameter.
The references of record relied upon by the examiner are:
Cope 3,761,692 Sep. 25,
1973
Katsumata et al. (Katsumata) 2,140,704A Dec. 5,
1984
Hurle et al. (Hurle) "A Technique for Experimentally
Determining The Transfer Function of a Czochralski Pulling
Process," Journal of Crystal Growth, Vol. 74, 1986 pages 480-
2
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