Instantaneous Generation of Many Flaked Particles by Impulsive Force of Electric Field Stress Acting on Inner Wall of Mass-Production Plasma Etching Equipment

Abstract

To elucidate the mechanism of instantaneous generation of many flaked particles in plasma etching equipment, we investigate the relationship between the generation of flaked particles from deposited films (consisting of etching reaction products on the ground electrode) and the plasma stability under mass-production conditions. Many particles are observed with our particle monitoring system when plasma instability occurs. The generation of such flaked particles correlates well with the occurrence of a large, rapid change in floating potential on the chamber wall. Our results indicate that many flaked particles from films deposited on a ground electrode are generated by electric field stress acting instantaneously and working as an impulsive force. #

Contamination Particles and Plasma Etching Behavior of Atmospheric Plasma Sprayed Y2O3 and YF3 Coatings under NF3 Plasma

“…Ceramic parts such as electrodes, shower heads, liners, and focusing rings used in these processes are exposed to the plasma. These parts erode and produce contamination particles, which cause serious problems, such as lowering the yield of mass-production [1][2][3][4][5]. In particular, when the dual frequency coupled plasma is applied, the showerhead in the position facing the wafer is heavily etched in a high flux of plasma [6][7][8][9][10].…”

Monitoring of Condition of Deposited Film Causing Particles in Plasma Etching by Using Practical Load Impedance Monitoring Method

“…After that, the etching reaction products are attached and gradually deposited on the inner walls as more wafers are processed, and the products formˆlms. Particles are generated from theˆlms due to electricˆeld stress, which acts at the boundary between the insulating inner wall and thê lm during plasma processing and causes theˆlm to ‰ake oŠ 6,[11][12][13][14] . The electricˆeld is formed between the inner wall surface at a ‰oating potential and the chamber at a ground potential.…”

Increase in Size of Flaked Particles Suddenly Generated by Impulsive Force in Mass-production Plasma Etching Equipment

“…During plasma etching process, the etching reaction products adhere to the inner walls of the process chamber, and gradually deposit asˆlms as many wafers are processed. The particles are generated by ‰aking of the depositedˆlms caused by electricˆeld stress that acts at the boundary between the insulating inner wall and thê lm 6,[11][12][13][14][15] . The electricˆeld is formed between the inner wall surface at the ‰oating potential (inner wall potential) and the chamber at the ground potential.…”

“…In addition, a lot of particles sometimes suddenly ‰ake oŠ and give rise to many defective LSI devices. We have previously elucidated the mechanism that the number of particles instantaneously increases when the electricˆeld stress acts as impulsive force [11][12][13][14] . An impulsive force is known in classical mechanics as a force becoming much larger as the time to act becomes much shorter 16,17) .…”

“…An impulsive force is known in classical mechanics as a force becoming much larger as the time to act becomes much shorter 16,17) . We have investigated the mechanism of sudden generation of many ‰aked particles, and elucidated that many particles are generated when the electricˆeld stress changes instantaneously and works as an impulsive force 11) . We have also clariˆed that the depositedˆlm can largely deform and ‰ake oŠ as many particles owing to the impulsive force of electricˆled stress, from the calculated result using the forced oscillation model 12) .…”