WILLIAMS Advanced Materials 

Custom packaging materials are designed to meet the diverse needs of hybrid manufacturers.

Williams’ die attach preforms' flexibility will eliminate thermal expansion mismatch and “down-bonding”. Williams has a vast tooling library of specially designed tools to stamp preforms from material with clad overlays that have been built and maintained by our in-house tool and die shop. Clad overlay preforms are available in squares, rectangles, disc and special shapes. Dimensions range from 0.005” total thickness, down to parts as small as 0.015” square. Williams also offers preforms stamped from base materials of Kovar, A42, Copper or Nickel that are then plated with Ni and/or Ni and Au. This type of preform is an excellent "heat spreader" within an electronic package. It’s available in size from 0.005” thick to 0.015” in length and width. Shapes include squares, rectangle, discs, and custom designs.

Williams moly tabs (die attach preforms), used as a die mount, act as a thermal conductor and as a buffer to compensate for the thermal expansion mismatch between the die and substrate, and can be easily removed for re-use if the package proves to be bad.  Moly tabs can either be clad materials or plated according to the customer's specifications.  Our extensive tooling library and "soft" tooling capabilities will ensure quick delivery and low cost.

A Williams bonding pad is a die attached preform with two layers of clad material product, typically using Copper, Kovar, or Alloy 42 as the base material; Aluminum as the top layer; and solder as the bottom clad layer.  Solder clad materials typically used are Gold-Silicon, Gold-Germanium, and Gold-Tin.  The bonding pad eliminates several problems by providing an Aluminum surface for wire bonding which eliminates "purple plague" and eliminates "down-bonding" (where the die cavity and bond finger are same height).  Because the bond pad has its own solder, it can be placed anywhere in the package.