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RF-LDMOS is the dominant RF power device technology in the cellular infrastructure market, having successfully displaced vertical MOSFETs and silicon bipolar transistors in the 1990s. A similar technology shift towards RF-LDMOS is occurring today in adjacent RF power markets such as UHF Broadcast, VHF Broadcast, L-Band and S-Band Radar, and the Industrial/Scientific/Medical markets (MRI, CO2 Laser, synchrotron, etc.). This increasing adoption of RF-LDMOS into these other RF power applications is the direct consequence of continuing progress at improving the intrinsic reliability and application-specific customization of LDMOS device structures.RF power applications, whether cellular infrastructure or the adjacent non-cellular markets, present unique and challenging thermal and electrical environments for the RF power transistor. While the design and architecture of the power amplifier is critically important in defining the stress environment, this presentation will focus on improvements of the intrinsic reliability of RF-LDMOS FETs. The most important of these intrinsic reliability characteristics are Hot Carrier Injection (HCI), Electromigration (EM), and device ruggedness. The stress environment presented to the RF power transistor will be described in detail, including the linkage between the RF stress and these intrinsic reliability metrics. Detailed models have been created to simulate these stresses, and the results of various device design strategies to mitigate these stresses will be presented.5A.2.8 IRPS11-442

This work examines the planarization of polymer thin film coatings derived from Cyclotene™ 3022 prepolymer resins. Cyclotene™ 3022 is a divinyl siloxane bis-benzocyclobutene prepolymer (DVS-BCB, CAS 117732-87-3). It is used primarily as a dielectric in microelectronics applications.Using profilometry, planarization measurements have been made on thin films spun over features consisting of lines and trenches. Feature widths have been varied from 2 to 1000 μm and the feature depths and film thickness have been varied from 1 to 16 μm. Effects of the processing procedure, resin concentration and resin additives have been explored. Local (versus global) planarization will be discussed.Planarization has been found to depend on all feature dimensions and the polymer film thickness. Lines or other structures having a width of 100 μm or less can be planarized to 90% or better with standard commercial formulations of Cyclotene™ 3022, provided that the mean film thickness is twice the line-height or feature-depth. Metals such as Al, Cu, Cr and Ti can all be planarized to this degree; however, surface preparations may influence the result.