Multi-cusp ion source for doping process of flat panel display manufacturing

Area of Science:

• Materials Science
• Plasma Physics
• Semiconductor Manufacturing

Background:

• Low-temperature polycrystalline silicon (LTPS) processes are crucial for flat panel display (FPD) manufacturing.
• Ion doping systems are essential components in LTPS fabrication.
• Existing multi-cusp ion sources face challenges with ion species ratio and beam uniformity in BF3 plasmas.

Purpose of the Study:

• To develop an improved multi-cusp ion source for the Nissin ion doping system iG5.
• To enhance the B(+) ion ratio in BF3 plasmas for LTPS processes.
• To achieve high-current, uniform ion beams for efficient FPD manufacturing.

Main Methods:

• Utilized BF3 or PH3 diluted H2 plasmas in a multi-cusp ion source.
• Developed a novel method to increase the B(+) ion ratio.
• Employed newly improved multi-slot type electrodes for beam extraction.
• Investigated and implemented cleaning methods for metal fluoride deposition.

Main Results:

• Achieved a mass-analyzed B(+) target current of 130 mA.
• Obtained stable ion beams with uniformity below 3%.
• Successfully addressed issues related to metal fluoride deposition in BF3 plasmas.

Conclusions:

• The developed multi-cusp ion source significantly improves B(+) ion generation and beam quality.
• The enhanced ion source is suitable for high-performance LTPS processes in FPD manufacturing.
• Effective cleaning methods are crucial for maintaining ion source performance and beam uniformity.