研究電漿蝕刻技術製作奈米級光阻線

Abstract

近四十年來，半導體業界伴隨著摩爾定律的魔咒，不斷地朝最小線寬挑戰，目前主流以193奈米波長的氟化氬雷射光源配合浸潤式微影技術可達線寬45奈米，但是相關設備必需付出高昂的成本。本論文是以電漿蝕刻技術在微影製程之後，再次加工，使光阻微縮，觀察趨勢；其中，實驗試片是以KrF雷射發射出248nm波長的深紫外線做為曝光源，光阻圖案為線條形、線寬為129.2nm，經He/O2氣體蝕刻140秒後，線寬微縮至48nm；若是He/O2混入氬氣(Ar)，在蝕刻120秒後，線寬則是84nm；若是He/O2混入二氟甲烷(CH2F2)，在蝕刻160秒後，線寬來到79.8nm。 以上三種製程配方，讓我們驗證以電漿蝕刻技術微縮光阻的可能性，並且此種技術確實有將光阻線寬微縮至奈米等級的能力，因此證明此種光阻微縮技術的構想是可行的方案之一。

The Moore's Law is the main driving force to push the semiconductor industry toward the minimal linewidth sacle during the past decade. The state-of-the-art technology for the large scale production in foundry industry is 45 nm, while 32 nm for small volume production now. All the above mentioned techniques adopt the very expensive immersion method and the light source is ArF laser light at 193 nm. In order to avoid the very expensive approach, this thesis uses the plasma etching technique for studing the fabrication of nanometer scale based photoresist lines. All the patterns are fabricated by using the relative cheaper light source called KrF laser at wavelength of 248nm as the exposure source. We obtain the initial photoresist pattern with linewidth of 129.2 nm, and are interestingly shrunk to 48 nm after 140 seconds He/O2 gas etching. The He/O2 gas in together with argon (Ar) gas does not improve the pattern after 120 seconds of etching- the best obtained linewidth is 84 nm. Similarly, the spiking of difluoromethane (CH2F2) into He/O2 gas after 160-second etching shrinks the linewidth to 79.8 nm. Our approach can push the photoresist pattern into nanoscale region by means of suitable etching gases and etching times.