超導 transmon 量子位元因其良好的可擴展性以及與現代微影製程技術的相容性，而成為量子資訊處理領域中最具潛力的平台之一。然而，約瑟夫森接面（Josephson junction）電阻的製程變異可能導致同一晶片上的量子位元頻率呈現較大的分散，並降低多量子位元系統中的元件均勻性。適當的頻率配置相當重要，因為頻率過度擁擠可能增加殘餘耦合、頻譜碰撞以及控制誤差，進而降低量子位元操作保真度。因此，製程後電阻調整技術提供了一種改善量子位元頻率可控制性與元件良率的實用方法。

本研究探討交替偏壓輔助退火（Alternating-Bias Assisted Annealing, ABAA）與雷射修整（Laser Trimming）兩種應用於超導 transmon 量子位元之製程後電阻調整方法。ABAA 利用交替電偏壓脈衝改變接面電阻，而雷射修整則利用局部光學加熱於製程完成後提高接面電阻。研究中透過電阻量測追蹤接面電阻於調整過程中的演變情形，並利用低溫量測分析修整後量子位元的頻率與同調特性。修整後的電阻漂移與老化效應亦被檢視，以評估元件於調整後的穩定性。

研究結果顯示，ABAA 與雷射修整皆能改變接面電阻，並具備量子位元頻率調整能力。ABAA 具有較漸進式的電阻調整特性，但其效果呈現明顯的元件依賴性；相較之下，雷射修整能夠更快速且有效地提高接面電阻，但對修整條件較為敏感，且可觀察到修整後的電阻漂移現象。低溫量測結果證實，經調整後的元件仍可作為 transmon 量子位元運作，並可量測得到包括 T1 與 T2 在內的同調參數。這些量測結果為評估電阻調整對元件性能之影響提供了依據。

整體而言，本研究驗證製程後電阻調整技術應用於超導量子位元之可行性，並為量子位元頻率調整、元件均勻性、電阻穩定性與同調特性分析提供參考。

Superconducting transmon qubits are among the leading platforms for quantum information processing because of their scalability and compatibility with modern microfabrication techniques. However, fabrication-induced variations in Josephson junction resistance can lead to a broad distribution of qubit frequencies across a chip and reduced device uniformity in multi-qubit systems. Proper frequency arrangement is important because unwanted frequency crowding can increase residual coupling, spectral collisions, and control errors, thereby degrading qubit operation fidelity. Post-fabrication resistance tuning, therefore, provides a practical approach for improving qubit frequency controllability and device yield.

In this work, alternating-bias assisted annealing (ABAA) and laser trimming were investigated as post-fabrication methods for tuning the resistance of superconducting transmon qubits. ABAA uses alternating electrical bias pulses to modify the junction resistance, while laser trimming uses localized optical heating to increase the junction resistance after fabrication. Electrical resistance measurements were performed to monitor the evolution of junction resistance during the tuning process. Cryogenic measurements were then used to characterize qubit frequency and coherence properties after trimming. Post-trimming resistance drift and aging effects were also examined to evaluate device stability after tuning.

The results show that both ABAA and laser trimming can modify the junction resistance and provide frequency-adjustment capability. ABAA offers gradual resistance tuning but shows device-dependent response, whereas laser trimming provides faster and more effective resistance increases with greater sensitivity to trimming conditions and observable post-trimming drift. Cryogenic measurements confirmed that the tuned devices remained operational as transmon qubits, with measurable coherence parameters including T1 and T2. These measurements provide a basis for evaluating the influence of resistance tuning on device performance.

Overall, this work demonstrates the feasibility of post-fabrication resistance tuning for superconducting qubits and provides practical insight into frequency adjustment, device uniformity, resistance stability, and coherence characterization in superconducting quantum circuits.

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