Biology Reference
In-Depth Information
As shown earlier, the microcomponent dimensions significantly
influence the yield of self-assembly. In addition, the area of pad
contact is also an important factor. The study included an evaluation
of both parameters (component size and contact-part size ratio).
The results are shown in Fig. 12.16.
Figure 12.16
Self-assembly yield vs. different contact-part size ratios.
(a) Components with similar contact-part size ratios; (b)
components with different contact-part size ratios; (c) 45
µ
µ
m part contacts on 45
m template alloy contacts; (d)
90
µ
m part contacts on 20
µ
m template alloy contacts;
m template alloy contacts.
Reprinted with permission from Ref. [11]. Copyright 2008
IOP Publishing Ltd.
(e) 90
µ
m part contacts on 90
µ
The results show that larger contact area and larger contact-
part size ratios lead to a higher yield for the low-melting solder
mechanism. In other words, the process is limited in terms of the
component size. One reason is the necessity to use acidic conditions,
which not only removes surface oxide but also continually consumes
the alloy material itself. Another possible reason is that the
intermetallic compound, which forms between the base metal and
the molten alloy, also gradually consumes the base metal. However,
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