TABLE OF CONTENTS It is important to understand the types of copper-clad laminates that are available, how they are made, where they are used, and the advantages and disadvantages of each before selecting the material most suitable for the intended application. Many types of copper-clad materials are available (see Fig. 2.4). The copper-clad laminates most widely used in the manufacture of printed circuit boards, however, are FR-2, CEM-1, CEM-3, FR-4, FR-5, and GI. These are the materials that are primarily discussed in this section.
The FR-2 laminates are composed of multiple plies of paper that have been impregnated with a flame-retardant phenolic resin. The major advantages of FR-2 laminates are their relative low cost and their good electrical and punching qualities. FR-2 is typically used in applications where tight dimensional stability is not required, such as in radios, calculators, toys, and television games.
FR-3, the other all-paper-base laminate, is also made of multiple plies of paper that have been impregnated with an epoxy-resin binder. The FR-3 laminate has electrical and physical properties that are higher than those of the FR-2 but lower than those of epoxy laminates that have woven glass cloth as a reinforcement. FR-3 is used to manufacture printed circuits used in consumer products, computers, television sets, and communication equipment.
CEM-1 is a composite material that has a paper core impregnated with epoxy resin. Woven glass cloth impregnated with the same resin covers the two surfaces. This...
