Photolithography

Summary

Photolithography is a technique that can be applied to form precise patterns in metal, oxide, nitride, and semiconductor films during the fabrication of the thin‐film transistor (TFT) arrays and color filters. This chapter discusses the main in‐line processes from photoresist coating to development for performing photolithography for the TFT arrays and color filters. It presents an overview of photolithography for TFT arrays. The chapter explains the photoresist coating methods and equipment, by focusing on the slit coating that is suitable for over Gen 6 glass substrate sizes. Puddle development is the major approach for over Gen 6 size TFT arrays. The chapter also discusses the photolithography for color filter manufacturing. It explores the exposure process with detailed explanations on the four main types of exposure equipment, as well as photoresist materials and UV light sources. The types of exposure equipment are stepper (Nikon), multi‐lens scan (Nikon), mirror projection (Canon), and proximity.