Reading time ( words)
For the purpose of this column, high-performance laminates are characterized as base materials that in one or more aspects exceed the performance of FR-4, CEM, or paper/phenolic laminates. The focus, however, is on low loss (Df), low Dk dielectric resin-based CCLs and prepregs. Included are laminates that distinguish themselves through higher Tg, better chemical stability, better dimensional stability, or some other performance factor. Polyimide-based flex laminates are covered briefly. Requirements for dielectrics specifically developed for HDI boards or flip chip packages, such as dielectric films for microvia build-up layers, laser-drillable prepregs, and various forms of RCC for rigid cores, are briefly mentioned to contrast these requirements to high-performance CCLs for second level packaging.
Market Overview—Applications
The applications for high-performance laminates are quite diverse and evolving rapidly. Low Dk and/or Df are common performance requirements in addition to many others that are shared with various applications. The high-performance laminate applications include:
• Cellular base station infrastructure (e.g., base station power amplifiers)
• LNBs (low-noise block down-converters)
• Cavity PCBs
• HF antennas
• High-speed digital backplanes
• High-speed routers
• High-speed servers
• High-speed test PCBs
• RF and HF microwave boards and modules
• High-speed chip packages
• Optoelectronic devices
• Satellite TV infrastructure
• Automotive collision avoidance systems
The automotive collision avoidance applications appear to be the highest frequency application at 40 GHz and above (current state-of-the-art radar chip systems, 77 GHz), and have a very high growth rate. It also demands dielectrics with very low loss.
Following is a list of commercial high-performance laminate constructions/compositions, as provided by the manufacturers:
• Woven E-glass/PPO
• BT/epoxy
• Woven E-glass/high-speed, low-loss epoxy
• Woven SI-glass, APPE thermoset resin
• Woven E-glass, ceramic filled thermoset hydrocarbon (polybutadiene)
• Woven SI-glass/high-speed, low-loss epoxy
• Woven glass, ceramic filled PTFE
• Woven glass, ceramic filled thermoset
Editor's Note: This article originally appeared in the January 2016 issue of The PCB Magazine.
