Development of conformal phosphor coating technique for light-emitting diodes using image-processing-based maskless lithography

• Published in: Microelectronic engineering Vol. 118; pp. 11 - 14
• Main Authors: Jang, Jisung, Han, Sangkwon, Chung, Su Eun, Choi, Yong Joon, Kwon, Sunghoon
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 25.04.2014; Elsevier
• Subjects: Applied sciences; Arrays; Chips; Chromaticity; Coating; Conformal phosphor coating; Cross-disciplinary physics: materials science; rheology; Electronics; Exact sciences and technology; Image-processing-based maskless lithography (IP-ML); Light-emitting diodes; Lithography; Materials science; Methods of nanofabrication; Microelectronic fabrication (materials and surfaces technology); Nanoscale pattern formation; Object recognition; Optoelectronic devices; Phosphors; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Surface treatments; White LEDs; Conformal phosphor coating; Image-processing-based maskless lithography (IP-ML); White LEDs; Coating process; Patterning; White light; Image processing; Color; Mask; Luminescent material; Real time; Light emitting diode; Thickness; Array; Microelectronic fabrication; Image-processing-based maskless; Manufacturing process; lithography (IP-ML); Optoelectronic device; Spatial light modulators; Chromaticity; Maskless lithography; Photolithography; Protective coatings; Recognition
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2014.01.006

•A conformal, chip-level phosphor coating technique using IP-ML was developed.•Conformal phosphor coating was performed on an LED array on a blue tape.•IP-ML make a chip-level conformal phosphor coating with contact openings.•The fabricated white LEDs provided a uniform color distribution.•Color binning can be carried out prior to the packaging process. We introduce a conformal phosphor coating technique for white light-emitting diodes (LEDs) using image-processing-based maskless lithography (IP-ML). The use of IP-ML allows real-time recognition of LEDs, which enables the generation of photo-patterning masks on a spatial light modulator by means of image processing, making the process suitable for a chip-level conformal phosphor coating with contact openings. This automated photolithographic chip array coating process enables phosphor coating onto chips with a consistent thickness, and the chips treated using this method show a narrow color distribution in which the chromaticity is controllable by varying phosphor thickness and concentration.