Hermetic chip carrier

Figure 2. Conventional chip carrier. This example with a lid is for hermetic applications. (Reproduced with permission from Ref. 4. Copyright 1988 BPA [Technology and Management, Ltd.].)...

Hermetic packages, such as the older flat pack design or ceramic leadless chip carriers (CLCCs), are used in harsh applications (such as military and space applications) where water vapor and contaminants can shorten the life of the device. Thus they are used in mission critical communication, and navigation and avionic systems. The reliability of CLCC package connections can be further improved by the attachment of leads to the connection pads, to eliminate differences in the thermal coefficient of expansion between the parts and the circuit board material. 

Several electronic applications of Sn-5Sb solder have been reported the creation of hermetic seals in multichip modules, bonding a semiconductor device onto a substrate [64], and attachment of I/O pins to multilayer ceramic substrates [65]. The braze alloy, Au-20Sn, used to attach I/O pins to ceramic chip carriers was replaced by Sn-5Sb solder. The replacement provided several... 

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