Rogers Corporation’s Power Electronics Solutions (PES) group will be exhibiting at PCIM Europe and introducing curamik ADVANTAGE, a family of features and process enhancements for its high-power curamik® ceramic circuit substrate materials.
curamik ADVANTAGE materials enable circuit designers to optimize the performance of their high-power circuits through a wide assortment of services and processes, including several plating options for improved copper surface finish, two different treatments for minimizing PCB surface roughness, selective etching, precise laser drilling of small-diameter through holes, addition of solder stop to prevent solder bridging, and optimization for advanced silver sintering process that offers an alternative to conventional solder device attachment.
High-voltage curamik ceramic-based circuit materials include curamik Power, curamik Power Plus, curamik Performance, and curamik Thermal, offering a broad range of thermal conductivities from 24 to 170 W/m-K. The materials are especially formulated to effectively disperse heat in power electronics circuits with heat-generating, high-power active devices, such as IGBTs and MOSFETs. The curamik ADVANTAGE family of features and services enhances both the usability and performance of the curamik materials, improving reliability in the process.
curamik ADVANTAGE includes a number of plating options for all four curamik circuit materials, such as nickel (Ni), nickel-gold (NiAu), and silver (Ag) plating. Silver plating can also be provided over selective areas, to allow some copper to remain bare. The plating processes are performed in-house by means of wet chemical etching, and help to improve the efficiency and effectiveness of circuit wire-bonding and soldering processes.
Additional curamik ADVANTAGE processes include chemical and mechanical treatments to improve surface roughness (Rz better than 7); treatment with solder stop to prevent unwanted flow of solder and formation of undesirable solder bridges; treatment of many of the curamik materials to provide partial-discharge-free performance; elimination of voids in curamik ceramic materials to enhance operating lifetimes; and laser drilling of through holes with minimum 1-mm diameter.
Perhaps the most significant process available as part of the curamik ADVANTAGE family of processes is the optimization for advanced silver sintering that serves as an alternative to conventional soldering for interconnections and device attachments. The silver sintering process forms strong bonds by applying heat to a paste containing miniature silver particles. Silver exhibits excellent thermal conductivity (240 W/m-K) and by controlling the size of the silver particles in the paste, silvering sintering can provide strong bonds with different grades of thermal performance for enhanced reliability. The silver sintering process can form joints with standard thicknesses ranging from 50 to 100 um, and even thinner thicknesses are possible.
curamik ceramic circuit materials are designed to provide reliable performance under high-temperature, high-voltage conditions. By selecting from among the various curamik ADVANTAGE process options, production can be simplified, reliability improved and performance enhanced for all four curamik materials.