August 9, 2011 – Doug Anberg, VP of advanced stepper technology at Ultratech, discussed the physics behind cost-of-ownership (CoO) improvements in the company’s new Sapphire 100E HB-LED tool in a video interview at SEMICON West 2011. With a low NA, good DoF, and the resolution required for HBLED applications, the 1X projection lithography tool eliminates the consumable costs (for masks) associated with contact aligners because the masks don’t contact the wafer.

Anberg noted that the company is seeing good acceptance of the new tool for layers called patterned sapphire substrates (PSS), and for the pad layer associated with the current spreading finger area (see figure below). The current spreading finger area needs reduced feature sizes to achieve good CD control and good lithographic performance, said Anberg. These attributes are key to obtaining more light output from the LED, especially for high-power devices used in solid-state lighting applications.

Performance considerations for HB-LED applications. (Source: Ultratech)