Pushing the Envelope - Wafer Level Packaging
Materion Barr Precision Optics and Thin Film Coatings has the reputation of pushing the envelope when it comes to new technology and higher quality levels. When the requirements for IR wafer level packaging (WLP) forced all previous practices to change related to coating silicon, we were already one step ahead. Materion has been developing improved coating capability for the WLP challenge since 2008 and has made significant strides in defect reduction. 80/50 is no longer considered an acceptable scratch dig specification. Companies are now requiring coating defects to be smaller than a third the size of a human hair or 20um. Coatings are also required to withstand temperatures up to 400 degrees Celsius. The new IR coatings at Materion achieve both objectives.
Materion did not stop there. Each package cavity requires close inspection for defects that cannot be seen by the human eye. To address this issue, Materion purchased an automated inspection tool and developed unique software that allowed mapping out of each cavity to determine if it would be acceptable for the end use. This allowed for the production of the highest quality product.
Materion is committed to providing new technology that will provide leading-edge solutions for customers. During 2013, Materion will build a wafer level coating work cell and invest capital in clean rooms, specialty coating chambers, and spray resist coating capabilities. The clean rooms will be classified as 10K with some areas being 1K and will have gowning areas and pass-through windows to ensure defects are kept to a minimum. The new line of customized in-house coating chambers will ensure that optical coatings can withstand 400 degrees Celsius, remain uniform across 150mm or 200mm wafers, remain uniform within each cavity with depths down to 300um, and reduce defects caused by the coating process. Other equipment within the work area will be a resist spay coater and an alignment tool for patterning. These will enhance the ability to further reduce defects and coat closer to the cavity sidewalls in order to increase the number of detectors per wafer and decrease cost to the customer.
Materion expects to continue to be a leader in coating silicon wafers as it has been in the past. In the last three years, we have delivered over 500,000 discrete windows for infrared detectors. Materion also provides AuSn and CuSn seal rings for eutectic bonding purposes and will continue offering these services in the new wafer level coating work cell. As we continue to push the technology envelope, Materion plans to streamline the coating process and create fully automatic semiconductor friendly IR coating chambers. This will help alleviate the industry-wide need for clean room coating chambers and facilitate quality service to our customers.
For more information on WLP services, please contact Robert.Legg@Materion.com.