多晶矽晶圓暗裂的非破壞評估及檢測：改良式超音波共振法

Abstract

多晶矽基板質地硬脆，容易產生細微裂縫，微小的裂縫能夠在太陽能電池模組製程中引起災難性破壞，甚至使整個模組在發電運轉中失效。裂縫偵測是矽晶圓與太陽能電池矽基板品管的一項重要課題，製造廠商若能在太陽能電池產品製造、封裝前，掌握缺陷的檢測，將可提升產品良率及追溯品質。本計畫為兩年期研究計畫，提出一項有效、全域的非破壞評估方法，偵測多晶矽太陽能電池基板的細微裂縫。第一年研究期間將結合超音波共振法及電子光斑干涉法，量測多晶矽太陽能電池基板的面內共振頻率及共振模態，並建立可供確認太陽能電池基板有無缺陷之電激發螢光實驗裝置。第二年將應用第一年建立之檢測方法，發展偵測多晶矽太陽能電池基板微裂縫尺寸及位置之改良式超音波共振法，協助業者建立多晶矽太陽能電池基板的品質檢測標準。

Micro-cracks are frequently found in brittle poly-crystalline silicon wafers and photovoltaic cells. These defects usually result in catastrophic damages when poly-crystalline silicon cells are assembled in module process and cause the cell failure in service. Crack detection is an important issue in quality control of silicon substrates or silicon-based photovoltaic cells. Manufacturers can tremendously improve yield and traceability if those defects could be detected before the cells are packaged. A two-year research program is proposed to develop an effective, full-field nondestructive evaluation method for micro-crack detection in poly-crystalline silicon cells. In the first year, an emerging method based on resonance ultrasonic vibrations (RUV) and electronic speckle pattern interferometry (ESPI) will be used to determine in-plane resonant frequencies and the corresponding mode shapes of defect free specimens. An apparatus of electroluminescence will be made as a benchmark for defect detection of the silicon cells. In the second year, the improved RUV method is used to inspect the size and location of cracks in ploy-silicon cells. This research benefits the establishment of inspection standard and quality assessment for photovoltaic cell industry