次微米介電泳微影技術開發

Abstract

半導體微影技術隨著電晶體的發展不斷進步，元件的尺寸也越做越小。但近年來傳統光學微影技術發展已幾達極限，以更短波長的光源做微影系統已越來越不符合成本。於是研究人員不斷地在尋求各種可能的下世代微影技術。 本實驗室提出一種新的成型技術，以液體介電泳原理驅動紫外光固化材料照光固化成型，稱為液體介電泳微影技術。其成型裝置只需二維圖形化電極，不需有像奈米壓印凹凸起伏的複雜結構。其技術原理是透過交流電場驅動液體，避開過去光學微影中光學繞射的解析度限制。 在本論文中，我們藉由液體介電泳驅動力在平行板裝置中完成568 nm 線寬的微影技術，成功地擴展了液體介電泳技術達到次微米尺度的領域，並且對光固化材料受氧氣限制效應的影響與突破，進行了一些深入的探討。本研究中使用PEGDA 及4-HBA-Si兩種紫外光固化材料，將其驅動流經500 nm線寬的電極再照光固化。並且，測試了在乾式蝕刻製程下的抗蝕刻阻擋能力，PEGDA材料在Poly-Si及SiO2的蝕刻製程中，其蝕刻率分別是29.9 Å/s 和26.7 Å/s ，而傳統的I-line正光阻則是20.6 Å/s及20.0 Å/s。這些結果顯示，藉由液體介電泳力驅動的光固化材料PEGDA，在次微米級半導體製程中將會是一個很好的應用機會。

Because the lithography technique is progressing continuously, the dimension of transistor device is getting smaller. Recently, development of traditional optical lithography technique is reaching the limit, and it is not practical to have an advanced optical lithography system by shortering the wavelength of the exposing light. Hence the researchers keep investigating the new method for next generation lithography. There are many methods that people have proposed and demonstrated including nano-imprint, step-and-flash imprint lithography and lithographically induced self-assembly. We propose a new lithography technique, called dielectrophoretic lithography, by solidifying UV curable materials driven by dielectrophoresis. Fabrication process of the device is simply patterning electrodes without any 3-D structure. Actuating liquid materials by applied an AC electric field could avoid the light diffraction limit. In this thesis, 500 nm lithography technique is achieved by liquid DEP in a parallel-plate device, which expands the DEP driving technique to sub-micrometer dimension field. In this work, PEGDA was solidified across a 500 nm wide line under UV light exposure. The dry etching resistances of PEGDA are 29.9 Å/s for Poly-Si dry etching recipe and 26.7 Å/s for SiO2 dry etching recipe. Meanwhile the dry etching resistances of traditional I-line photo resist are 20.6 Å/s for Poly-Si and 20.0 Å/s for SiO2. These results show that solidifiable PEGDA material driven by DEP force is able to modern sub-micrometer semiconductor fabrication.