• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2511-2514
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• 2008

As the minimum feature size decreases, techniques to avoid contamination and processes to maintain clean wafer surfaces have become very important. The deposition and detachment of nanoparticles from surfaces are major problem to integrated circuit fabrication. Therefore, cleaning technology which reduces nanoparticles is essential to increase yield. Previous megasonic cleaning technology has reached the limits to reduce nanoparticles. Megasonic cleaning is one of the efficiency method to reduce contamination nanoparticle. Two major mechanisms are active in a megasonic cleaning, namely, acoustic streaming and cavitation. Acoustic streaming does not lead to sufficiently strong force to cause damage to the substrates or patterns. Sonoluminescence is a phenomenon of light emission associated with the cavitation of a bubble under ultrasound. We studied a correlation between sonoluminescence and sound pressure distribution for the minimum of pattern damage in megasonic cleaning.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.845-846
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.631-632
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• 2008

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.364-365
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• 2006

Transverse some wave was generated by T type waveguide for single wafer cleaning application T type megasonic waveguide was analyzed by acoustic pressure measurements and particle removal efficiency. Compared to conventional longitudinal waves, not like longitudinal waves, transverse waves showed changes of direction and phase which increased the cleaning efficiency.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.10
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• pp.1535-1540
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• 2001

This study presents the possibility of scratch reduction on wafer in CMP by applying the ultrasonic and megasonic energy into the slurry which might contain large abrasive particles. Experiments were conducted to verify the dispersion ability of agglomerated particles by applying ultrasonic, megasonic waves and analyze the particle distribution of used slurry in case, of sonic energy assisted or none. And the dispersion stability of megasonic waves was investigated through the experiment of stability of the dispersed slurry, Finally, to confirm that the distribution of particles in slurry by ultrasonic waves was actually related to scratches on wafer when CMP was done, tungsten blanket wafer was processed, by CMP to compare and investigate scratches on wafer.

• Journal of the Semiconductor & Display Technology
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• v.22 no.2
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• pp.17-23
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• 2023

In semiconductor manufacturing processes, a cleaning process is important that can remove sub-micron particles. Conventional wet cleaning methods using chemical have limits in removing nano-particles. Thus, physical forces of a mechanical vibration up to 1 MHz frequency, was tried to aid in detaching them from the substrates. In this article, we developed a 1 MHz quartz megasonic for a bare wafer cleaning using finite element analysis. At first, a 1 MHz megasonic prototype was manufactured. Using the results, a main product which can improve a particle removal performance, was analyzed and designed. The maximum impedance frequency was 992 kHz, which agreed well with the experimental value of 986 kHz (0.6% error). Acoustic pressure distributions were measured, and the result showed that maximum / average was 400.0~432.4%, and standard deviation / average was 46.4~47.3%. Finally, submicron particles were deposited and cleaned for the assessment of the system performance. As a result, the particle removal efficiency (PRE) was proved to be 92% with 11 W power. Reflecting these results, the developed product might be used in the semiconductor cleaning process.

• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.66-71
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• 2023

This paper describes a hybrid cleaning method of silicon wafer combining nano-bubble and ultrasound to remove sub-micron particles and contaminants with minimal damage to the wafer surface. In the megasonic cleaning process of semiconductor manufacturing, the cavitation induced by ultrasound can oscillate and collapse violently often with re-entrant jet formation leading to surface damage. The smaller size of cavitation bubbles leads to more stable oscillations with more thermal and viscous damping, thus to less erosive surface cleaning. In this study, ultrasonic energy was applied to the wafer surface in the DI water to excite nano-bubbles at resonance to remove contaminant particles from the surface. A patented nano-bubble generator was developed for the generation of nano-bubbles with concentration of 1×10⁹ bubbles/ml and nominal nano-bubble diameter of 150 nm. Ultrasonic nano-bubble technology improved a contaminant removal efficiency more than 97% for artificial nano-sized particles of alumina and Latex with significant reduction in cleaning time without damage to the wafer surface.

• Journal of the Semiconductor & Display Technology
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• v.13 no.1
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• pp.1-6
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• 2014

In this study, to analyze characteristics of acoustic pressure for spot spray type megasonic, FEM analysis was performed for variable parameters based on the structure of commercial one. and 2 models of transmitter were designed and fabricated, and then acoustic pressure distribution(APD) of the transmitter was measured and compared to the commercial. The results of this experiment show that maximum acoustic pressure of model 1 was higher to 1.6 times compared to the commercial, and model 2 was higher to 1.23 times. Through the course of this study, design technology of transmitter has been developed by means of FEM analysis and experiment for characteristics of acoustic pressure. Also, it is expected to be useful in the development of high power spray type megasonic that is necessary with advance in semiconductor technology.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.59-59
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• 2009

현재 CMP분야는 광역 평탄화 반도체 소자의 집적화 및 소형화가 진행됨에 따라서 CMP 공정의 중요성은 날로 성장하고 있다. 하지만 이러한 CMP공정은 불가피하게도 scratch, pit, CMP residue와 같은 defect들을 발생시키고 있으며, 점점 선폭이 작아짐에 따라, 이러한 defect들이 반도체 수율에 미치는 영향은 심각해지고 있다. Defect들 중에 특히 scratch는 반도체에 치명적인 circuit failure를 일으키게 된다. 또한 반도체 내구성과 신뢰성을 감소시키게 되고, 누전전류를 증가시키는 등 바람직하지 못한 현상들이 생기게 된다. 본 연구에서는 scratch 와 같은 deflect들을 효율적으로 검출, 분석하고, scratch를 감소시키는데 그 목적이 있다. 본 실험을 위해 8" TEOS wafer와 commercial oxide slurry 및 friction polisher (Poli-500, G&P tech., Korea)를 사용하여 CMP 공정을 진행하였으며, CMP 공정조건은 각각 80rpm/80rpm/1psi(Platen speed/Head speed/Pressure)에서 1분 동안 연마를 한 후 scratch 발생 경향을 살펴보았다. CMP 후 wafer위에 오염되어 있는 slurry residue들을 제거하기 위해 SC-1, HF 세정을 이용하여 최적화된 post-CMP 공정기술을 제안하였다. Scratch 검출 및 분석을 위해 wafer surface analyzer (Surfscan 6200, Tencor, USA)와 optical microscope (LV100D, Nicon, Japan)를 사용하였다. CMP 공정 변수들에 따른 scratch 발생정도를 비교하였으며, scratch 발생 요인들에 따른 scratch 형태 및 발생정도를 살펴보았다. 최적화된 post-CMP 세정 조건은 메가소닉과 함께 SC-1 세정을 실시하여 slurry residue들을 제거한 후, HF 세정을 실시하여 잔여 오염물들을 제거하고 검출이 용이하도록 scratch를 확장시킬 수 있도록 제안하였으며, 100%의 particle removal efficiency (PRE)를 얻을 수 있었다. 실제 CMP 공정후 post-CMP 세정 단계별 scratch 개수를 측정한 결과, SC-1 세정 후 약 220개의 scratch가 검출되었으며, 검출되지 않았던 scratch가 HF 세정 후 확장되어 드러남에 따라 약 500개의 scratch 가 검출되었다.