A low cost multichip packaging technology for monolithic microwave integrated circuits

Abstract

This paper describes a multichip module technology based on highly impermeable liquid crystal polymers (LCP's) to interconnect and package monolithic microwave integrated circuits (MMIC's). Because of the low moisture permeability of the LCP's, the packages can be made hermetic without heavy expensive housings and can be two to four times lighter and onefifth the cost of conventional ceramic based transmiVreceive (T/R) modules. The LCP material has a low dielectric constant (2.65) and low-loss tangent and is manufacturable using high volume, large-area processing methods that provide very reliable highperformance circuits at low cost. Using flip-chip bonded MMIC's attached to a high thermal conductivity, low coefficient of thermal expansion substrate, this innovative technology can meet a variety of commercial, military, and NASA requirements.

Characterization of Liquid Crystal Polymer (LCP) Material and Transmission Lines on LCP Substrates From 30 to 110 GHz

“…It has been around in thin-film form since the early 1990s when it was first recognized as a candidate for microwave applications [5], [10], [11]. However, early LCP films would easily tear and were difficult to process.…”

“…A biaxial die extrusion process was developed [8], [9], [11], which solved the tearing problems by giving the material uniform strength and it also created additional processing benefits. It was discovered that by controlling the angle and rate of LCP extrusion through the biaxial die, the -coefficient of thermal expansion (CTE) could be controlled approximately between 0 ppm C and 40 ppm C. Thus, this unique process can achieve a thermal expansion match in the --plane with many commonly used materials.…”

LCP Based Planar High Q Embedded BandPass Filter for Wireless Applications

“…The practice of LCP as a microwave circuit substrate is not a new idea. It has been around in thin-film form since the early 1990s when it was first documented as a candidate for microwave applications [10][11][12].…”

On-chip micromachined dipole antenna with parasitic radiator for mm-wave wireless systems

“…Nevertheless, they suffer from narrow bandwidth [6]. With the development of integrated circuit technology, the conventional waveguide technology has been gradually replaced in most applications with microwave integrated circuit (MIC) technology [7] and monolithic MIC (MMIC) technology. In these technologies the traditional bulky waveguides and antennas are replaced with planar counterparts.…”