Photolithography and mask alignment

Photolithography is the imprint of a pattern into a polymer photoresist in order to leave selected areas of the substrate protected or unprotected for subsequent processing. It is a critical step in the construction of devices from extended semiconductor or metal films. It is currently one of the most active areas within the cleanroom.

The full suite of lithography tools are available and substrate sizes from 10 x 10 mm² up to 150 mm wafers can be processed. The patterning of implantation masks as well as metal, semiconductor or insulator layers like Al, Al/1.5%Si, Au, Cr, Ta, a-Si, a-Ge, SiO₂, Si₃N₄, is possible via the following equipment:

Direct Laser Writer (Durham Magneto-optics)
Substrates	suitable for 10 x 10 mm² subtrates, up to 100 mm wafers
Application	maskless laser written patterns with ~ 2 µm overlay capabilities on semiconductor and glass substrates
Mask-Aligner MA6 (SÜSS Microtech)
Substrates	up to 150 mm substrates
Application	one- and two-sided photolithographic patterning of metal, semiconductor or insulator films on semiconductor and glass substrates
Spin-Coater LabSpin6 (SÜSS)
Substrates	up to 150 mm substrates
Application	spin coating of wafers with photoresists (usually S1805 and S1813)
Spin-Coater APT Polos (SPS Europe B.V.)
Substrates	up to 150 mm subtrates
Application	like GYRSET RC 518

XY-dimensions and accuracy of patterned layers can be controlled and measured by optical microscopy combined with a CCD camera and the interactive measuring unit MFK II.