Product Briefing Outline: Pixer Technology has launched ‘Galileo,’ which it claims to be the industry’s first high speed, high resolution DUV metrology tool that enables measurement of DUV transmission with a 0.1 percent resolution limit and is sensitive to transmission changes of 0.01 percent. The tool is for use on advanced mask blanks at the 45nm node and below. 

Problem: With the challenge of ever-decreasing CD uniformity (CDU) requirements in lithography, even mask blank contribution can be significant. At 45nm half-pitch logic, 0.5 percent transmission non-uniformity can account for 40-50 percent of the overall intrafield CDU budget. Mask blanks typically have better than 0.1 percent non-uniformity. With Galileo, blank manufacturers have the ability to determine which blanks are best for critical litho steps, according to Pixer Technology.

Solution: Galileo enables measurement of DUV transmission with a 0.1% resolution limit and is sensitive to transmission changes of 0.01%. Measurements can be made on both quartz and MoSi coated blanks. Sensitivity, it is claimed, is not compromised by the speed of the tool. For example, over 1000 sample points can be measured in less than 20 minutes, according to the company.

Applications: Both quartz and MoSi coated blanks.

Platform: The Galileo is built on a common platform with the CDC200.

Availability: February 2008 onwards.

Mask Transmission Mapping:

These maps demonstrate the very sensitive measurements now available on the Pixer Galileo tool. Standard mask blanks are compared with the low birefringence mask blanks used for critical layer immersion lithography.  Galileo can also measure MoSi-coated attenuating phase-shift mask blanks in addition to uncoated quartz. Note that the low birefringence blank has a 10X better transmission range than the standard blank and meets requirements for the 45nm node.