SEMATECH, a global consortium of semiconductor manufacturers, has released the results from its annual mask survey, which provides a comprehensive look into both the business and technical aspects of the mask industry.
The survey, which was recently presented at the 2013 SPIE Photomask Technology Conference in Monterey, CA, identified defect mitigation and write time as the current top challenges, with critical tool readiness and capability as the top concern for the development of next-generation masks.
SEMATECH’s 12th Annual Mask Industry Survey is part of a collaborative effort to address critical infrastructure gaps, particularly related to the introduction of EUV lithography such as mask blanks, resists and aerial image inspection.
“The annual survey results give mask makers a way to assess their own progress relative to their peers, and provides the semiconductor industry and supply chain with critical insight into the capabilities and needs of the mask industry,” said Matt Malloy, SEMATECH manager leading the industry survey. “The feedback we received from this year’s survey demonstrates that mask shops are working harder than ever to deliver top quality products to their customers even as mask complexity and fabrication time are increasing.”
Highlights from the survey include:
All-time high yields for 6-inch binary, attenuated phase shift, and alternating phase shift masks were reported at 97.7 percent, 93.3 percent, and 92.7 percent, respectively.
All participating mask shops reported shipping masks targeting the 22 nm node or smaller, and on average, yields were greater than 90 percent at all nodes down to 22 nm.
The number of masks per mask set has seen a 14 percent long-term growth rate with the average number more than doubling from 23 at the 250 nm node to 54 at the 22 nm node.
At the 250 nm node the minimum and maximum number of masks per mask set reported were 18 and 28, while at the 22 nm node the minimum and maximum reported were 40 and 83; the increased range likely due a combination of product type, patterning strategy and other factors.
Data and Write Time
Write time continues to increase rapidly with a maximum reported write time of 60 hours (2.5 days), confirming the need for faster mask writers such as the multi-beam mask writers currently in development.
Data size, which has seen a long-term annual growth rate of approximately 40 percent, has stabilized over the past five years and was ranked low on the list of top concerns.
A 22 nm mask has an average turnaround time of 8.3 days, which is three times as long as the turnaround time for a 250 nm node mask.
Maintenance and Returns
Survey results showed that 99 percent of masks sent for routine maintenance were sent back to the customer after work was completed, while only 47 percent of true mask returns were eventually sent back to the customer. The remaining 53 percent were discarded.
Hard defects remain the leading cause of yield loss for both binary and phase shift masks, validating defect mitigation as the top concern among the mask survey participants.
Chamber cleaning was identified as the leading source of defects, with lithography materials and mask blanks following closely behind.
The survey was conducted with input from nine merchant and captive mask shops, including Advanced Mask Technology Center (AMTC), Dai Nippon Printing (DNP), Hoya, IBM, Intel Mask Operation, Samsung, Semiconductor International Manufacturing Co. (SMIC), Toppan Printing, and Taiwan Semiconductor Manufacturing Co, Ltd. (TSMC). Traditional topics such as breakdowns of mask shipments by ground rule, application, glass size, process type, etc. were included in the survey to continue monitoring trends, and several new topics were added in 2013 based on industry input and feedback.