Nd-YAG雷射退火無電鍍鎳製程參數最佳化之探討

A Study on the Optimum Parameters in Laser Annealing Electroless Nickel-Plated

江孟鴻(Meng -Hong Jiang)

指導教授 ： 簡文通

國立屏東科技大學/工學院/機械工程系所/碩士(2007年)

https://doi.org/10.6346/NPUST.2007.00022

摘要

本研究是利用無電鍍鎳於鏡面鐵基板上，然後對此無電鍍鎳薄膜進行雷射退火處理，目的在建立退火後薄膜硬度最大值和薄膜表面平均粗糙度最小值時之雷射退火參數最佳化模式。研究流程可分成兩個單一品質目標及多重品質目標分析兩階段。首先利用田口法直交表規劃實驗配置，選定氣體種類、尖峰功率、脈衝寬度、脈衝頻率、聚焦高度、退火速度、退火重複及脈衝重複率等為雷射退火參數。以薄膜硬度及薄膜表面平均粗糙度為量測對象，並分別選定為兩個單一品質目標，藉由田口法分析分別求取在其最佳值時之雷射退火參數組合。接著利用灰關聯分析，找出同時考慮最佳薄膜硬度及薄膜表面平均粗糙度為多重品質目標之最佳退火參數組合。結果顯示在單一品質目標之最佳退火參數分析中，分別得到之最佳薄膜硬度為13.41GPa，薄膜表面平均粗糙度為30.84nm，此單一品質最佳化結果與未退火時薄膜之硬度和薄膜表面平均粗糙度比較，分別改善73.0％及72.0％。在灰關聯分析結合田口法之多重目標最佳雷射退火條件分析中，可得到薄膜硬度為11.69GPa，薄膜表面平均粗糙度為35.22 nm，此多重品質最佳化結果與未退火時薄膜之硬度和薄膜表面平均粗糙度比較，分別改善50.8％及68.0％，由於考量多重目標可較符合實際加工上的應用，本研究證實灰關聯分析結合田口法可以得到良好的結果，而單一目標與多重目標之分析結果均可提供適用性及多樣性的加工參數之選擇。此外，利用TEM分析觀察薄膜雷射退火前後之金相變化，結果顯示薄膜未退火前為非晶質結構，經雷射退火後其組織轉變為Ni3P之結晶結構，由於Ni3P之析出導致Ni基地晶格變形，產生析出硬化效果，而使薄膜硬度獲得提升。同時觀察其橫截面，發現無電鍍鎳薄膜與鐵基板並無擴散現象，與傳統退火有所差異。最後利用雷射對不同pH值之無電鍍鎳薄膜進行退火，結果顯示pH值越低時能接受之雷射功率越高，且無裂紋產生。此最佳化模式分析過程、結果及各種現象應可做為與雷射退火相關研究之參考，並提供雷射加工相關產業之應用。
關鍵詞：雷射退火、無電鍍鎳、最佳化參數、多重品質目標、灰關聯分析

關鍵字

雷射退火 ； 無電鍍鎳 ； 最佳化參數 ； 多重品質目標 ； 灰關聯分析

並列摘要

The purpose of this study is to establish a model for searching optimum laser annealing parameters to obtain a maximum value of hardness and a minimum value of average surface roughness for the film that nickel has know deposited nickel on a mirror surface iron base plate by an electroless process then treated by a laser annealing process.
The study processes can be deviled into tow phases including tow single quality objectives and a multiple quality objective. Firstly, an orthogonal array of Taguchi method was used for arranging the experiments in which the gas type, peak power, impulse width, impulse frequency, focal height, annealing speed, annealing repetition and impulse repeatability were selected as the laser annealing parameters. The measured values for film hardness and the film surface average roughness were treated as a single quality objective, separately .The optimum parameters combination to attain the best quality for the objectives caw be found separately by using Taguchi method. Then the grey relational analysis was used to find the optimum annealing parameters combination for the multiple quality objective that considering a maximum film hardness and a minimum surface average roughness at the same time. It can be found that a film hardness as 13.41Gpa and a film surface average roughness as 30.84nm were obtained for the single quality objectives, separately. When the results were compared with the films without annealing treatment, an improvement of 73.0% and 72.0% were achieved, separately. While a film hardness as 11.69Gpa and a film surface average roughness as 35.22nm were obtained for the multiple quality objective. The improve met was 50.8% and 68.0%, separately, when compared with the films without annealing treatment. Both analytic results of single-objective and multi-objective can provide applicable and diversified options for choosing parameters in fabrication; however, the multi-objective which combining Taguchi method with grey relational analysis is more suitable in a practical process. In addition, the change of film atomic phases has been observed by TEM analysis before and after laser annealing. It is shown that the film is a amorphous structure before annealing and the structure transferred to be a Ni3p crystal structure after annealing. The function of the precipitation of Ni3p results in the lattice deformation in the Ni base that causes a precipitation hardening effect hence the film hardeners increases. It is also observed that there is no diffusion condition between the electroless nickel film and iron base plate in the cross sections. The phonomenum is different from a traditional annealing process. Furtheremore, some different pH values of electroless nickel film were selected for laser annealing. The experimental results showed that a lower pH value of film would lead to a higher a laser power acceptance. The analytic process its results and all of the phenomena in this optimized model can provide a useful reference and application for research and industrial fields in a laser annealing process.

Keywords: Laser Annealing, Electroless Nickel-Plated, Optimum Parameters, Multiple Quality Objective, Grey Relational Analysis

並列關鍵字

Laser Annealing ； Electroless Nickel-Plated ； Optimum Parameters ； Multiple Quality Objective ； Grey Relational Analysis

參考文獻

[6]吳錫侃，1984，雷射表面硬化，材料科學，台北，15-22頁。

[34]C. B. Chen, C. T. Lin, C. W. Chang, and C. P. Ho, 2000, “Grey Relation for Solving Multi-Quality characteristics Problems of Taguchi Methods,” Journal of Technology , Vol. 15, pp. 25-33.

[35]D. Barder, 1993, “Electroless deposition of metals,” Trans. Inst. Metal Finish, pp.285-353.

[37]G.O. Mallory ,and J.B. Hajdu, 1990, “The fundamental aspects of electroless nickel plating,” Electroless Plating : Fundamentals and Applications, AESF, Vol. 9, pp. 37.

[38]oldman, J. R., and J. A. Prybyla, 1994, Ultrafast dynamics of laser-excited electron distributions in silicon. Phys. Rev. Lett., Vol. 72, pp. 1364-1378.