Wilmington, MA. Rudolph Technologies at SEMICON West last week highlighted its new patented Clearfind technology, which can detect organic defects that are difficult or impossible to see with conventional white-light imaging techniques. Organic contaminants are often the root cause of field failures, which occur after the material has been exposed to operating conditions for extended periods.
Rudolph said it has been actively collaborating with several key customers to fully understand their inspection challenges and how the new technology addresses them, and plans to incorporate Clearfind technology in its upcoming defect inspection systems for advanced packaging applications.
“As advanced packaging processes become more complex, process windows are shrinking and manufacturers are seeking better methods for control and inspection that balance the need for high throughput against the ‘escape’ of true defects and the ‘false positive’ detection of nuisance defects,” said Mike Goodrich, vice president and general manager of Rudolph’s Process Control Group. “Organic defects, in particular, have become more troublesome as die interconnects shrink and there is less surface area for good adhesion. Clearfind technology will help our customers see these defects earlier in the process, permitting faster action to mitigate the root cause and reducing the amount of product in jeopardy.”
Goodrich continued, “Using laser illumination we are able to clearly identify residue defects that typical white-light optics would miss. In addition to optimizing the wavelength of the illumination to enhance detection, we have specifically designed the mechanics of the system to accommodate the high warpage found in advanced packaging applications.”
Clearfind technology highlights organic residues on bumps and bond pads or at the bottoms of vias so that they are easy to detect. On metals, it eliminates the high-contrast graininess seen under conventional illumination, resulting in an obvious defect signal against a featureless background. This same graininess in conventional imaging can also cause false positives, which are especially costly at this stage of the process where the sunk cost of unnecessarily rejected good product is high. Finally, Clearfind technology readily detects shorts and opens in metal lines when inspected with an underlying organic layer. Rudolph believes these capabilities will significantly increase its customer’s ability to detect process and manufacturing related issues earlier, resulting in significant yield, which equates to millions of dollars in savings, especially for processes utilizing known-good die. Rudolph’s customers see this as a critical technology to improve quality for their customers in order to avoid the high costs of replacement and penalties.