使用蝕刻技術製造超導量子迴路晶片

本文所使用的超導量子位元稱為Transmon，超導材料為鋁，其製作約瑟夫接面(Josephson junction)的方式為Cross junction，使用的電容為指叉式(Interdigital)電容。我使用的超導量子迴路晶片是利用半導體製程所製造，利用微影技術使用正光阻定義出圖形，再將鋁蒸鍍在矽晶圓上並利用濕蝕刻製程完成共面波導，透過共面波導我們能夠將微波送入超導量子位元晶片並觀察和控制反應出的現象。利用蝕刻製程所完成的共面波導在金屬邊緣粗糙程度較低，相較於剝離製程這有助於減少background cavity mode也有益於超導量子位元減少pure dephasing。設計上共面波導的阻抗為50Ω，而在我的參數製作下共面波導的線寬誤差約1.9%、阻抗約50.68Ω。約瑟夫接面設計線寬190nm，實際結果為247.1nm和275.1nm。

關鍵字

量子；量子電腦；超導體；半導體製程；製程；蝕刻

並列摘要

The superconducting qubit used in this paper is called Transmon, the superconducting material is aluminum, the method of fabricating the Josephson junction is Cross junction, and the capacitor used is an Interdigital capacitor. The superconducting quantum circuit chip I used is manufactured using a semiconductor process, using lithography technology to define a pattern using positive photoresist, and then vapor-depositing aluminum on a silicon wafer and using a wet etching process to complete a coplanar waveguide through the coplanar waveguide. We can send microwaves into superconducting qubit wafers and observe and control the reflected phenomena. The coplanar waveguide completed by the wet etching process has less roughness on the metal edge. Compared with the lift-off process, this helps to reduce the background cavity mode and also benefits the superconducting qubits to improve decoherence. In the design, the impedance of the coplanar waveguide is 50Ω, and the line width error of the coplanar waveguide is about 1.9\% and the impedance is about 50.68Ω under my parameters. The Joseph junction design line width is 190nm, and the actual results are 247.1nm and 275.1nm.