Direct encapsulation of OLED on CMOS

Abstract

The integration of organic light-emitting diodes (OLED) into semiconductor technology (CMOS) requires a protection, called encapsulation, which covers the OLED forming a barrier against the environment (oxygen, moisture, mechanical). The essential encapsulation technology has to be suitable for full-wafer production regarding low chip cost, fast throughput and accurate processing. A combination of thin-film and direct encapsulation might result in a proper protection for organic devices, containing the advantages of a good barrier, mechanical protection, easy extension with light-forming components and a pre-protection. Aligned adhesive wafer bonding technology is characterized for this hybrid encapsulation approach. A flow of fabrication steps is discussed, which builds up a sandwich of a CMOS wafer with the OLED and a cover glass wafer with color filter structures. This process flow manufactured an OLED microdisplay, which is implemented in a head-mounted display demonstrator.