Process Materials implements a proprietary technique to metallic bond sputtering targets and backing plates. Our bonding process ensures the thermal integrity of the interface between the system's cooling assembly and the surface of the target, which experiences the most heat.  The bonding of the sputtering target to a backing plate is a very critical procedure.  Process performance and process stability are highly dependent on a good bond.  Custom fixtures and gauges are used to provide precise control of solder layer thickness and target/backing plate alignment, securing a high integrity bond.

Backside Metallization

Process Materials sputter deposits backside metallization layers on targets before bonding.  This metallization accomplishes the following:

• Enhancement of adhesion to the target.
•  Prevents reactions and diffusion between the target and solder layer or  backing plate.
• Electrical and thermal contact

Bonding/Solder Material

The most common material used is high purity indium, which is applied without the use of flux.  indium is compatible with all target materials.  Indium allows higher operating temperatures than other indium alloys.  Indium has a melting temperature of 156 degrees C.  When metallic bonding is inappropriate, targets can be bonded with a high conductivity silver as an alternative.

Tolerances

Process materials procedures allow all geometric tolerances to be maintained at very close limits.  The parallelism of the targets and the thickness of the bonding layers are tightly controlled.  All incoming customer backing plates are inspected and measured prior to bonding.

Bond Integrity

The most critical area of the bond is the periphery, the bond seam.  Even the smallest void or an oxide layer may cause severe process instabilities.  Each target seam is inspected to guarantee shape, continuity and integrity of the region.  Process Materials guarantees that, on average, at least 97% of the target area is solidly bonded.

Quality

Whether you use the most common backing plate material, OFHC copper, molybdenum, stainless steel or aluminum, Process Materials quality bonding techniques eliminates cavities at the edges of a solder bond that may entrap air and form a virtual vacuum leak in your sputtering system.  We make every effort to prevent bond flaws that might degrade the base pressure in the sputtering chamber and the target's performance.