Appeal No. 1999-1286
Application No. 08/567,950
This collimation device 9 will comprise, for example, a convergent
lens to focus the beam 6 if it is desired to mark circuits with a surface area
smaller than the diameter of beam 6.
it is also possible to provide for modifying the marking diameter of
the circuits by modifying the position of the wager with respect to the focal
plane of the lens:
— either by providing for means to shift this convergent lens
in the collimation device 9,
— or by modifying the relative positions of the platform 2
and of the collimation device 9, which is more complicated from the
control point of view. . . .
* * * *
Preferably, the vertical translation of the platform 2 will be used
. . . .
We agree with the examiner that this passage does not expressly describe a method
wherein the spot size of the laser beam is varied from spot to spot while marking a
single defective integrated circuit. We have reviewed the remainder of the
specification, but find no written description that adequately supports Appellant’s
position. At page 4, Appellant states, “[t]his is why, in an alternative version, the
defective chip is marked at several places, for example with a geometrical figure”
(emphasis added). At page 11, Appellant describes the factors that affect time it takes
to mark the circuit:
“If the marking diameter is smaller, the time of exposure to the
beam 7 could be reduced in order to have an identical melting depth. It is
also possible, in this same example, to keep an identical exposure time
and change the lens 15 to reduce the transmission coefficient of this lens.
Depending on the nature of the surface layers of the circuits, for
marking diameters that vary from 300 to 1000 microns and assuming that
the exposure time is in the range of 1 millisecond . . .
Of course, to appreciate the total amount of time taken to mark the
circuit, it is necessary to take account of the laser recharging time
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