Appeal No. 1999-0725
Application 08/476,475
solder ball because "when removed from the molten solder, the volume
of solder which adheres to the film tends to take a shape which has
minimum surface area" (col. 2, lines 69-71); i.e., it is formed into
a ball shape from a liquid state, albeit not by reflowing a solid to
a liquid state. Noll discloses that a thin film 50 of low melting
point solder is formed by dipping the crystal 10 into a pot of solder
(col. 3, lines 1-13). The capped solder ball in Noll is essentially
identical to the capped solder ball in Appellants' figure 2; however,
claim 1 is directed to the method of making. Noll does not disclose
placing a mask over the solder ball as recited in claimed step (b)
and does not disclose depositing a layer of low melting point metal
over the solder ball through the mask as recited in claimed step (c).
Microelectronics discloses formation of a conventional solder
ball or controlled collapse chip connection (C4). The lead and tin
components are deposited in layers as shown in figure 6-14(c)
(according to the legend; however, it is actually shown to the left
of the label "(b)"). "Reflow in an H2 ambient furnace at about 350°C
melts and homogenizes the pad and brings it to a spherical shape."
Page 378. The reflowed solder ball is shown in figure 6-14(d)
(according to the legend; however, it is actually shown next to the
label "(c)"). Thus, as deposited, the solder does not form a solder
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