West Chicago-based PCB fabricator American Standard Circuits has recently incorporated the Ormet Paste Process to their capabilities, enabling next generation z-axis interconnects.

When making this announcement, President and CEO Anaya Vardya said, “We have known about this product for a while now and a year ago we decided to give it a try. So far we have been very impressed with what we can do with it. It does a good job when it comes to thick board layer constructions as well as mixed dielectrics. We have yet to explore all of the applications and look forward to learning more regarding what this process enables.”

The Ormet Paste Process has been around for some time but the industry is just now starting to catch up with the technology. The product can be used for several different applications, with ASC’s main focus being on using it to make Z-axis connections during lamination.

The product can be used to help with the following:

Thick boards - Layer Reduction:

  • Overall thickness concerns: Reduction of aspect ratio by splitting a board into separate builds and joining with Ormet paste which can improve plating and drilling issues that come with high aspect ratios.
  • Elimination of back drilling and/or flip drilling.

High Speed Cap – Mixed Dielectric Builds:

  • No hole plating of high-speed layers.
  • Separate fabrication of high-speed layers results in smoother outer layer surface resulting in improved RF performance.

“Any Layer” HDI Using Paste:

  • Z-axis conductors applied prior to lamination.
  • Paste interconnects used to connect 2-layer cores in a single process step.

The Ormet Paste Is Different Because:

  • Transient Liquid Phase Sintering – Compositions comprising powder metallurgy (90% by weight) mixed in particulate form.
  • During thermal processing - The alloy becomes molten and reacts with metal to form new alloy compositions and/or intermetallic compounds. This reaction continues until one of the reactants is fully depleted (reaction starts at 150C, normal lamination temperatures). This is unlike most silver pastes which are held together by the polymer.

This also forms a metallurgical bond with metals it is in contact with. So, in some cases the paste can be used instead of plating.