Improvement of industrial scale photolithography control and process in 3D microLED industry

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Volume Title

School of Chemical Engineering | Master's thesis

Date

2024-09-10

Department

Major/Subject

Functional Materials for Global Challenges

Mcode

Degree programme

Master's Programme in Advanced Materials for Innovation and Sustainability

Language

en

Pages

66

Series

Abstract

This work presents the characterisation and enhancement of industrial-scale photolithography technologies utilised in the 3D microLED industry. Important facets of photolithography are included in the study, such as metrology, development procedures, statistical process control (SPC), and uniformity improvement. Hexamethyldisilazane (HMDS) contact angle is carefully evaluated, and defectivity is monitored during the photolithography process. The mean, standard deviation, and frequency of defects are tracked and managed using SPC charts. The thesis also looks into ways to improve the uniformity of photoresist thickness after development and minimise the amount of developer and deionized water used in the photolithography process. The outcomes of the experiments show notable increases in process efficiency and stability, which improves microLED output overall. The modification of the developper recipe and adjustment of the UV light intensity of the mask aligner dropped the uniformity of the thickness of developed photoresist from 20,3 % to 6,2 %. The creation of a new recipe to optimise the consumption of TMAH cut the volume used by half. This study emphasises the significance of exact process control and resource optimisation, offering insightful information and workable ideas for improving photolithography procedures in the microelectronics sector.

Description

Supervisor

Franssila, Sami

Thesis advisor

Gibert, Philippe

Keywords

photolithography, SPC, metrology, development, uniformity, photoresist

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