1-19
Q23. How do the two types of monolithic IC construction differ?
Q24. What is isolation?
Q25. What methods are used to deposit thin-film components on a substrate?
Q26. How are thick-film components produced?
Q27. What is a hybrid IC?
Q28. What is the primary advantage of hybrid circuits?
PACKAGING TECHNIQUES
Once the IC has been produced, it requires a housing that will protect it from damage. This damage
could result from moisture, dirt, heat, radiation, or other sources. The housing protects the device and aids
in its handling and connection into the system in which the IC is used. The three most common types of
packages are the modified TRANSISTOR-OUTLINE (TO) PACKAGE, the FLAT PACK, and the
DUAL INLINE PACKAGE (DIP).
Transitor-Outline Package
Transistor-Outline Package. The transistor-outline (TO) package was developed from early
experience with transistors. It was a reliable package that only required increasing the number of leads to
make it useful for ICs. Leads normally number between 2 and 12, with 10 being the most common for IC
applications. Figure 1-19 is an exploded view of a TO-5 package. Once the IC has been attached to the
header, bonding wires are used to attach the IC to the leads. The cover provides the necessary protection
for the device. Figure 1-20 is an enlarged photo of an actual TO-5 with the cover removed. You can easily
see that the handling of an IC without packaging would be difficult for a technician.
