極紫外線光光罩傳送盒去除微污染之研究

The study of micro-contamination removal from Extreme Ultraviolet pod

封振勳(Jen-Shiun Feng)

指導教授 ： 胡石政

國立臺北科技大學/機電學院/能源與冷凍空調工程系碩士班/碩士(2014年)

https://doi.org/10.6841/NTUT.2014.00511

摘要

根據摩爾定理(moore's law)，半導體電路上可容納的電晶體數目，約每隔24個月便會增加一倍。但是在2010年國際半導體技術發展路線圖顯示，在2013年年底便會開始偏離，之後電晶體數量密度預計變更為每三年增一倍。為了能讓定律繼續適用，極短紫外光微影技術(EUV)是目前被視為最有效的方法，尚未出現可以應用在極短紫外光微影技術的防塵薄膜材料，雖然光波波長只有13.5nm，可以進行更小尺寸的微影技術，卻由於光波越短所以越容易受到環境的影響，以至於照射過程是必須在真空環境下進行，無法採用舊式DUV防塵薄膜來隔絕微粒，因此需要一個特殊的設計實施存放、運輸，防止光罩受到汙染。
氮氣充填已經證明可以有效的阻止在晶圓片表面上來自空氣中的水氣沉積。藉由氮氣充填與真空技術的相互比較，希望找出新型EUV Pod (Extreme Ultraviolet Mask Pod, EUV光罩盒)上，在水氣和微粒的去除的優化。
本研究所選用的EUV Pod是用雙層盒來設計，保護方式主要是利用進、出氣口的濾膜和內外盒的間隔來做微粒、水氣的隔離，但已經進入到EUV Pod的汙染物仍需要做清除。故此研究實驗探討：1.運用氮氣充填，觀察水氣和微粒的去除效率。2.運用真空系統，觀察水氣和微粒的去除效率。 3.比較兩者之間的優劣。從實驗發現濾膜孔徑過小對充填效率影響極大，真空移除與氮氣充填的差異，在於內盒與外盒裡面的潔淨度是否同步。在水氣移除上，真空系統較充填優秀。在微粒方面，0.130μm以下的微粒數與微粒粒徑呈二次多項式關係；真空系統會經破空過程使微粒隨氮氣進入EUV pod內，導致去除效率較差。

關鍵字

氮氣充填 ； 真空技術 ； EUV Pod ； 水氣 ； 微粒 ； 光罩傳送盒

並列摘要

According to Moore's Law, the number of transistors on an integrated circuit can accommodate approximately every 24 months will be doubled But in the 2010 International Technology Roadmap for Semiconductors shows will begin deviation from the law at the end of 2013.Then, the number density of transistors will double every three years is expected to change. Order to make the law will continue to apply, extreme ultraviolet (EUV) lithography is currently regarded as the most effective way. But in extreme ultraviolet lithography technology, there is no material of pellicle capable to apply on EUV lithography. Because the wavelength of light is only 13.5nm, lithography can be smaller. However, due to the shorter waves so the more susceptible to the environment, the irradiation process must be carried out in a vacuum environment. The DUV pellicle which used to isolate the particle is not suitable anymore. Therefore requires a special design and implementation of storage, transportation, pollution prevention mask.
Nitrogen purging has been proven to be effective to prevent the surface of the wafer from the deposition of water vapor in the air. By combining nitrogen purging the vacuum technique over a decade of experience, hoping this technology can achieve the expected results in the removal of water vapor and particulates from the EUV Pod.
In the research, all experiment is using EUV Dual Pod, whose protection is using the filters of the inlet and outlet, and the interval between the carriers to isolate the particle and water vapor. But the contamination which is already entered into the EUV Pod must be removal. Therefore, the experiments in the research to explore: (1) Observing Removal efficiency of humidity and particles after nitrogen purging. (2) Observing Removal efficiency of humidity and particles after vacuum system. (3) Comparing the pros and cons on these both system.
The selected EUV Pod in the study is designed with double pods, mainly protection is depended on the filters which is set on the inner and outter pod, and the gap between the inner and outter pod. These can be isolated water vapor and particle, but the micro-contamination which has entered into EUV Pod must be to remove. Therefore experimental studies investigate: 1. Use nitrogen purging, observe water vapor and particulate removal efficiency. 2 using vacuum system, observe the removal efficiency of water vapor and particles. 3 compare the pros and cons between these systems.
It was found that the pore size of filters will affect purging efficiency a lot. The differences between vacuum system and purging system, is that the cleanliness of the inner box and outer box can be synchronized. About vapor removal efficiency, the vacuum system is better than the purging system. About particle, the numbers that the particle size is smaller than 0.130μm, was a quadratic polynomial related with particle diameter. After pressurize process, particles will enter into the EUV pod with nitrogen. This is the reason why the particle removal efficiency of the vacuum system is worse.

並列關鍵字

nitrogen purging ； vacuum technology ； EUV Pod ； vapor ； particle ； mask transfer Pod

參考文獻

1. S. Wurm. Extreme Ultraviolet lithography development in the United States. Jpn. J. Appl. Phys 46, 6105 (2007).

2. International Technology Roadmap for Semiconductors (ITRS), 2011 Edition, http://www.itrs.net/ Links/2011ITRS/Home2011.htm.

3. D.Y. Chan. EUV mask readiness and challenges for the 22nm half pitch and beyond. Proc. SPIE 7985, 79850A (2011).

4. A. Rastegar, S. Eichenlaub, A. Kadaksham, B. Lee, M. House, S. Huh, B. Cha, H. Yun, I. Mochi, K. Goldberg. Particle Removal Challenges of EUV Patterned Masks for the Sub-22nm HP Node. SPIE 7636, 76360N (2010).

5. O. Brux, P. van der Wallea, J.C.J. van der Doncka, P. Dress. Investigating the intrinsic cleanliness of automated handling designed for EUV mask pod-in- pod systems. Proc. of SPIE Vol. 8166 81662S, (2011)