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Author Mercado, L.L. ♦ Tien-Yu Tom Lee ♦ Shun-Meen Kuo ♦ Hause, V. ♦ Amrine, C.
Sponsorship IEEE Components, Packaging, and Manufacturing Technology Society ♦ IEEE Components, Packaging and Manufacturing Technology Society
Source IEEE Xplore Digital Library
Content type Text
Publisher Institute of Electrical and Electronics Engineers, Inc. (IEEE)
File Format PDF
Copyright Year ©1999
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Physics ♦ Electricity & electronics
Subject Keyword Switches ♦ Radiofrequency microelectromechanical systems ♦ Wafer scale integration ♦ Packaging ♦ Contacts ♦ Conducting materials ♦ Micromechanical devices ♦ Radio frequency ♦ Gallium arsenide ♦ Thermal conductivity
Abstract In discrete radio frequency (RF) microelectromechanical systems (MEMS) packages, MEMS devices were fabricated on silicon or gallium arsenide (GaAs) chips. The chips were then attached to substrates with die attach materials. In wafer-level MEMS packages, the switches were manufactured directly on substrates. For both types of packages, when the switches close, a contact resistance of approximately 1 /spl Omega/ exists at the contact area. As a result, during switch operations, a considerable amount of heat is generated in the minuscule contact area. The power density at the contact area could be up to 1000 times higher than that of typical power amplifiers. The high power density may overheat the contact area, therefore affect switch performance and jeopardize long-term switch reliabilities. In this paper, thermal analysis has been performed to study the heat dissipation at the switch contact area. The goal is to control the "hot spots" and lower the maximum junction temperature at the contact area. A variety of chip materials, including Silicon, GaAs have been evaluated for the discrete packages. For each chip material, the effect of die attach materials has been considered. For the wafer-level packages, various substrate materials, such as ceramic, glass, and low-temperature cofired ceramic (LTCC) have been studied. Thermal experiments have been conducted to measure the temperature at the contact area and its vicinity as a function of dc and RF powers. Several solutions in material selection and package configurations have been explored to enable the use of MEMS with chips or substrates with relatively poor thermal conductivity. For discrete MEMS packages, placing the die inside a copper cavity on the substrate provides significant heat dissipation. For wafer-level packages, thin diamond coatings on the substrate could reduce the hot-spot temperature considerably.
Description Author affiliation :: Semicond. Products Sector, Motorola, Tempe, AZ, USA
ISSN 15213323
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2003-08-01
Publisher Place U.S.A.
Rights Holder Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Volume Number 26
Issue Number 3
Size (in Bytes) 1.90 MB
Page Count 9
Starting Page 318
Ending Page 326

Source: IEEE Xplore Digital Library