Integrated circuit (ICs) chips are conventionally enclosed in packages that provide protection from environmental conditions and enable electrical interconnection between the semiconductor chips and other electrical components, such as a printed circuit board or a motherboard. In many cases, packaged semiconductors are produced by adhering an IC to a lead frame, attaching bond wires between IC pads and lead frame pins, and then surrounding the lead frame and the IC with an encapsulant, such as epoxy resin. In other cases, the encapsulant is omitted, and the IC and lead frame are covered with a ceramic lid, leaving the bond wires surrounded by air.
In particular, LDMOS power transistors are often packaged with bond wires surrounded by air to reduce parasitic coupling to the bond wires and maintain high Q levels. Such packages are produced, for example, by mounting an LDMOS power transistor die to a metallic substrate and/or lead frame, mounting passive components to provide matching, tuning and other functions. The IC and passive components are then covered with a ceramic composite lid, which is typically sealed tightly to protect the semiconductor devices from environmental factors. Packaging semiconductor devices in this manner, however, is costly, because each IC is separately and individually packaged.
For example, conventional power transistor package 1 is illustrated in FIG. 1. Transistor 7 and capacitors 5 are mounted on substrate 8. Package 1 contains metallic ground connection 2, radio frequency (RF) output and direct current (DC) input 3. Package 1 also contains RF input 4. Ceramic lid 6 is placed over substrate 8 and tightly sealed to complete the package for power transistor 1.