Appeal No. 96-1805
Application 08/200,432
Black is concerned with preventing voids between bonded
wafers which are caused by the presence of particulate or gas.
Black specifies that the wafers are made of silicon material.
The reference points out that particulate voids can be eliminated
by bonding the wafers in a dust-free chamber (page 2773, column
2), and that gas voids between the wafers can be eliminated if
the gas between the wafers during the bonding operation "is
either capable of combining with the silicon (e.g. oxygen) or
diffusing out of the bubble void through the silicon" (page 2776,
column 2). In addition to oxygen, the reference mentions
hydrogen and helium as being appropriate gases (page 2774, column
1, lines 3 and 4). Black also comments that some wafer pairs
were
mated in high vacuum (page 2774, columns 1 and 2). In the
conclusion section of the article, after stating that gas voids
can be eliminated by combining with the wafer or diffusing
through it, it is said that "[m]ating the wafers under high
vacuum was also effective" (page 2776, column 2, emphasis added),
which would seem to establish that the authors did not
contemplate utilizing hydrogen gas plus vacuum conditions in the
bonding chamber. This understanding is confirmed by the
examiner, who states on page 11 of the Answer that "[t]he use of
9
Page: Previous 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Next
Last modified: November 3, 2007