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Gold Spitting - Potential Solutions for Customers

What factors contribute to the defect-causing behavior known as “gold spitting” during the evaporation process and what can be done to prevent it? Senior Scientist, Dr. Alan Duckham of Materion Microelectronics & Services, addressed this common industry problem and offered potential solutions during his presentation at the 2013 International Conference on Compound Semiconductor Manufacturing Technology (CS Mantech Conference) in New Orleans.

Paper Covers Gold Spitting Contributing Factors

In the paper Developing a Fundamental Understanding of Gold Spitting During Evaporation , Dr. Duckham considers factors that can contribute to gold “spitting.” During evaporation processes, and in particular, the process of being deposited as a thin film onto a semiconductor wafer, gold can be prone to eject droplets that solidify into solid particles on the wafer, otherwise known as spitting.

Top Recognition in Poster Session

In the Poster Session of the Show, Dr. Duckham’s presentation was honored as the “Best Poster Award” by ballot vote of conference attendees. The popular poster generated much traffic and numerous discussions with process engineers from the compound semiconductor industry regarding how gold spitting can impact sputtering yields and product quality.Alan Duckham CS Mantech Poster

Materion Continues R&D

The highly controlled, gold spitting experiments were conducted at the Applications Laboratory in Westford, MA. The new lab expands Materion’s ability to work with other company facilities and its diverse experts. This collaboration is reflected in the gold spitting paper, which in addition to Dr. Duckham, was co-authored by Lawrence Luke, Applications Engineer, Materion Microelectronics & Services, and Robert Sprague, Director of Technology, Materion Barr Precision Optics & Thin Film Coatings.

Key Factors in Spitting

The Lab studies discovered that the factors affecting spitting can be divided into two broad groups: 1) evaporation process parameters and 2) material quality. If these parameters are not carefully regulated, a process results with significant variation in spitting. For a controlled process, the quality of the gold (Au) plays a significant role in the degree of spitting. That is why Materion’s level of Au purity and cleanliness reduces the amount of spitting. View the full technical paper