雷射直寫鈀觸媒於無電鍍銅沉積之應用

Formation of Pd Catalyst by Laser Irradiation for Electroless Copper Deposition

張雅慧(Ya-Hui Zhang)

指導教授 ： 王詠雲 ； 萬其超

國立清華大學/工學院/化學工程學系/碩士(2007年)

摘要

文獻中提及利用雷射誘導醋酸鈀的裂解反應乃使用有毒的氯仿作為溶劑。於本論文，我們選擇丙酮作為取代溶劑，乃因其與醋酸鈀有高的相容性，且其本身具有低沸點的特性。因此，本實驗改善雷射直寫製程，利用二倍頻Q-開關的Nd:YAG 雷射於塗布有固態醋酸鈀膜/丙酮的PI 基板上進行反應。 從UV-vis 光譜及非熱光源的實驗結果證實醋酸鈀的裂解機制乃為熱裂解程序。評斷此製程的優劣標準之一是當酸鈀膜進行熱裂解時，如何有效的控制線路大小。事實上，橫向之解析度不佳的問題可藉由擴束光的直徑大小解決。在光路設計中引進適當的望遠鏡透鏡系統而可獲得約25μm寬的鈀線. 由X 光電子能譜儀觀察得知，醋酸鈀膜經雷射直寫後會在直寫區產生純鈀金屬及部分還原態的醋酸鈀。經10 分鐘無電鍍沈積後，於不同雷射能量下沈積除來的鈀線皆被增厚約至280nm 高。此間接證明部分還原態的鈀可被無電鍍槽液進一步還原成具有催化活性的鈀觸媒。 關於銅導線的性質探討，我們利用EDX 檢測的銅線組成，並利用兩點探針分析銅線的電阻率。結果發現約有高達95wt%含量的銅金屬。而其電阻率可低至2-5μΩ-cm。

關鍵字

雷射直寫 ； 裂解機制 ； 無電鍍銅 ； 二步驟法 ； Q-開關Nd: YAG 雷射

並列摘要

Previous literature regarding laser process inducing the decomposition of thin palladium acetate layer utilized toxic chloroform as the solvent. In this study, we chose acetone instead of toxic chloroform due to its high
compatibility with palladium acetate and low boiling point. Therefore, an improved technique of second harmonic Q-switched Nd:YAG laser direct writing from solid film of palladium acetate/acetone on PI substrates was developed in this study.
The results of UV-vis spectra and non-thermal light sources indicate that the decomposition mechanism of palladium acetate is dominated by pyrolytic process. Therefore, a critical criterion of this process is the dimension control by pyrolytic decomposition of the palladium acetate layer. Indeed, the poor lateral resolution can be improved by introducing an appropriate telescopic system into the optical design. Eventually, palladium pattern of 25μm in width has been fabricated.
In addition, the result of x-ray photoelectron spectroscopy (XPS) revealthat pure Pd metal together with partial reduction of palladium acetate (Pdx) was both generated on the irradiated region after laser direct-writing. Copper lines of constant 280nm in thickness are achievable under different laser energies after electroless copper deposition for 10 minutes. The constant thickness implies that partial reduction of palladium acetate (Pdx) can be reduced to catalytic Pd metal in subsequent electroless copper bath.
As for examining the quality of the deposited copper wires, energy dispersive x-ray spectroscopy (EDX) and two-point probe were employed to analyze the elemental composition and the resistivity of the deposited copper
wires, respectively. The result of EDX demonstrates that the copper content could up to 95wt%. Moreover, the resistivity of copper wires can be as low as 2-5μΩ-cm.

並列關鍵字

laser direct-writing ； decomposition mechanism ； electroless copper ； two-step deposition method ； Q-switched Nd: YAG laser

參考文獻

3. Matthias Geissler and Younan Xia, Advanced Materials, 16, 1249(2004).

4. K. G. Ibbs and R. M. Osgood, Laser Chemical Processing for Microelectronics, Cambridge university press, (1989).

7. Van Hecke, Gerald R. Karukstis, A guide to laser in chemistry, Boston, Mass. Jones & Bartlett Publishers, Inc., Ch.4 (1998).

8. J. Lawrence and L. Li, Laser modification of the wettability characteristics of engineering materials, Professional Engineering Publishing, Ch.1(2001).

9. R. J. Von Gutfeld, E. E. Tynan, R. L. Melcher and S. E. Blum, Applied Physics Letters, 35(9), 651(1979).