Advantages of Using Pre-Molded Leadframe Packages for RF and MEMS Applications

摘要

The Air Cavity Package (ACP) is a widely used option for RF products, hybrid circuit assemblies and optical/photonic devices. Typical ACPs are metal cans and ceramic leadless chip carriers (LCC). Custom ACPs are also provided by machined metal housings and LTCC options. However, over the past 10 - 15 years, the development of MEMS Sensors and LED devices has seen the use of thermoplastic pre-molded leadframe packages become the top choice for custom application specific housings. These products are now maturing and moving to "standard" package outlines where possible. Currently, the experience gained with sensors is being reviewed by the emerging RF application markets. Here, LDMOS power and MMIC devices are widely used in wireless network applications that require low cost, lightweight, robust packaged devices. The electronics industry has pushed the development of thermoplastic materials to suit higher temperature applications, especially as a result of the introduction lead-free (RoHS) processing conditions. Liquid Crystal Polymers (LCPs) are the choice for plastic body components and connectors, developed to suit temperatures of 300 degrees C and above. This means that packages made with such materials can withstand the typical reflow soldering processes used in high-volume system manufacturing. However, the properties of LCPs present a number of manufacturing challenges for users. Hence, Interplex has developed in-depth design, manufacturing and test skill sets that can match the needs for smaller, lower cost plastic ACP packages, such as QFN, utilizing a range of LCP materials. This presentation will look at some of the stages of the development of MEMS packages, already engineered to suit robust, high-volume applications. It will detail some of the necessary test processes now required to qualify the technologies and show how the materials and manufacturing processes can be developed to provide enhanced reliability for non hermetic class packages. Further Interplex will propose some new development concepts that will extend the performance of these materials to meet the more stringent needs of the developing RF and power component markets for better performance packages.