矽晶圓與銅基板接合之結構特性研究

A study of the structures and properties of the bonded silicon-copper substrates

王柏森(Bo-Sen Wang)

指導教授 ： 蘇程裕

國立臺北科技大學/機電學院/製造科技研究所/碩士(2010年)

摘要

近年發光二極體產業蓬勃發展，在發光效率未有重大突破之前，若要維持高功率發光二極體之壽命，整體散熱能力將是重點。本研究將探討如何將發光二極體結構直接鍵結於散熱銅基板上，且同時維持高反射率及強度，藉以捨棄多餘之封裝製程及成本。
本研究利用擴散與晶圓接合技術，設計膜層接合機制以達到矽晶圓-銅基板接合的目的，首先在晶圓試片與銅基板上分別濺鍍黃金薄膜與鉻膜，銅基板上之鉻膜為阻擋層防止銅擴散，再使用自行設計之銀合金靶材濺鍍銀-銅-鈦薄膜做為接合及反射層。並在真空低溫條件下進行金、銀合金擴散接合。接合界面利用OM與SEM觀察其接合微結構，XRD及EPMA確認相態及擴散反應，光譜儀檢視反射率之變化，最後利用附著力測試及耐候實驗觀察其強度與品質。
研究顯示Au及ACT1膜層經過擴散接合，會形成均勻固溶相，此系統之耐溫性可達950℃。附著力測試此系統可得到最大10Mpa之抗拉強度。ACT1反射層經高溫及長時數之熱處理製程，仍可維持穩定的反射率。

關鍵字

銀合金反射層 ； 晶圓接合 ； 擴散接合 ； 發光二極體 ； 散熱基板

並列摘要

Because of the increasing developed of light emitting diodide (LED) industry, it is important to extend the lifetime of the LED by enhancing the heat dissipation efficiency. The aim of the present study focuses on the preparation of the LED structure bonding on the copper substrates exhibiting high reflectivity and intensity with the demand of low cost and simplified manufacturing process.

We used the diffusion and wafers bonding technique to achieve silicon wafer-copper substrate bonding. At first, gold and Cr thin films were deposited on the silicon and copper substrate, respectively. The Cr thin films were served as barrier layer to prevent the copper diffusion. Then, the bonding and reflection layers were prepared by sputtering the sliver alloy target. The diffusion bonding process for gold-silver alloy was performed in the vacuum system under low temperature. The microstructure of the bonding interface was observed by OM and SEM; in addition, the phase identification and diffusion process were confirmed by XRD and EPMA. The optical spectrometer was used to observe the reflectivity of the as-prepared thin films. Finally, the strength and quality of the bonding structure were identified by adhesion and durability tests.

The results show that the solid solution would be formed by Au and ACT1 layer through diffusion bonding and can reach 950℃. The maximum tensile strength of the layer can reach 10 MPa. ACT1 anti-reflective layer still maintains stable reflectivity after treating at high temperature and long duration.

並列關鍵字

Ag alloy Reflective layer ； Wafer bonding ； Diffusion bonding ； Light Emitting Diodide ； Cooler

參考文獻

[2] H. Amino, N. Sawaki, I. Akasaki and Y. Toyoda, “Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AlN buffer layer”, Applied Physics Letters,Vol.48, No.5, 1986, pp.353-355.

[3] S. Nakamura, M. Senoh, N. Iwasa, S. Nagahama, T. Yamada , T. Mukai,“High-power InGaN single-quantum-well-structure blue and violet light-emitting diodes, Applied Physics Letters, Vol.67, 1995, pp. 1868.

[4] C. Huh, J. M. Lee, D. J. Kim, and S. J. Park, “Improvement in light-output efficiency of InGaN/GaN multiple-quantum well light-emitting diodes by current blocking layer”, Journal of Applied Physics, Vol.92, No.5, 2002, pp. 2248.

[5] R. H. Horng, D. S. Wuu, S. C. Wei, “AlGaInP/AuBe/glass light-emitting diodes fabricated by wafer bonding technology”, Appl. Phys. Lett, Vol. 75, No. 2, 1999, pp.154-156.

[6] W.C. Peng, Y.C. Wu, “High-power AlGaInP light-emitting diodes with metal substrates fabricated by wafer bonding”. Appl. Phys. Lett, Vol. 84, No. 11, 2004, pp. 1841-1843.