Thick resist photolithography is an indispensable element of wafer bumping and advanced wafer level packaging in general. Leading systems for these processes are mask aligners and steppers, while for resist coating applications spin and spray coaters dominate.

Mask aligners are 1X full field exposure systems that offer an excellent cost of ownership and ease of use compared to competing stepper technology. All SUSS production aligners can be equipped with the Large Gap Exposure Optics (LGO) optics enabling near vertical sidewalls at highest aspect ratios in resist films up to 100 microns and thicker.

The challenges of photoresist processing in the field of waferbumping and wafer level packaging requires very careful design of coat, bake and develop modules in order to attain suitable production quality performance. Spin and spray coaters from SUSS MicroTec are the preferred system for many wafer level packaging coating applications such as thick resists or photosensitive polymers, such polyimide or BCB.