With 300mm wafer processing, expect to see a shift from conventional proximity aligners to more applications of 1x steppers for backend bump processing. While passe for leading-edge frontend applications, 1× steppers provide clear advantages for semiconductor manufacturing's backend, in cost of ownership, automation, and processing. Advantages include broadband exposure, superior automatic alignment, and overlay performance. The 2μm resolution capability of these tools is more than adequate for even difficult bump applications. In addition, these tools' low 0.16 NA provides a large depth of focus (5.0μm at the resolution limit of 2.0μm), which is useful in imaging thick resist.
展开▼
