Chapter 11Fabrication of Inorganic LEDs
LED manufacturing involves several processes starting from semiconductor wafers, then adding epitaxial layers and metal layers, dicing, mounting, and packaging. ese packaged LEDs are then assembled to form dierent consumer products (Figure 11.1). is chapter treats the processes that have to be performed from the wafer stage to the LED die stage. Special laboratories called semiconductor clean rooms are constructed for keeping the air pure and free from dust particles up to one part in 10,000, and maintaining specic temperature and humidity levels. e general cleanliness of the laboratories and incoming wafers is checked closely. Often, many fabrication steps are automated for consistency. All these measures are taken to improve the manufacturing yield, that is, the number of successful LED chips per wafer.