中文摘要

本研究探討利用不同析鍍條件及方式，以期能改善控制無電鍍鎳隆點之成長。本實驗首先改變鍍液組成中硫酸鎳鹽及還原劑次磷酸鈉的濃度，以獲得較佳之析鍍速率，之後比較以連續析鍍及間斷析鍍方式析鍍無電鍍鎳，對於析鍍速率及鍍層性層之影響。本研究進而以上述所獲較佳實驗條件，探討覆晶接合隆點金屬墊大小、間距，以及無電鍍鎳液穩定劑，對於無電鍍鎳隆點的表面形態及其成長行為的影響。
實驗結果發現濃度為60g/L硫酸鎳及35g/L次磷酸鈉之鍍液組成，無電鍍鎳析鍍反應之析鍍速率最快。比較連續析鍍及間斷析鍍對析鍍成長的影響，總析鍍時間在約120分鐘以前，連續析鍍的析鍍速率皆大於間斷析鍍之析鍍速率; 120分鐘以後，連續析鍍無電鍍鎳之析鍍速率有減慢的趨勢，間斷析鍍之析鍍速率則維持近似一定或些微增快之趨勢。
在固定之金屬墊尺寸及間距大小的條件下，隨著醋酸鉛濃度為0、0.25ppm或更高時，無電鍍鎳隆點之鍍層邊緣分別由過度成長轉為異向性及階梯狀的金字塔成長。未添加醋酸鉛作為穩定劑時，在不同的金屬墊尺寸及間距大小條件下，鍍層邊緣仍然維持過度成長，金屬墊尺寸愈小，愈呈過度成長;添加濃度1.5ppm之醋酸鉛作為穩定劑時，金屬墊尺寸減小及間距增加，則鍍層呈現金字塔成長之階梯狀區域越明顯。且當金屬墊尺寸小於150mm時，醋酸鉛明顯地阻礙無電鍍鎳隆點之析鍍速率。

Abstract

This research investigates the different deposition conditions and methods to effectively control the growth of electroless nickel bump. It manipulates the nickel sulphate and sodium hypophosphite concentration to achieve optimum deposition rate. It then compares the effect of continuous and intermittent electroless nickel deposition operation on deposition rate. Furthermore, the pad size, pitch size, and stabilizer concentration are investigated for their effects on the electroless nickel bump structure.
The results show that the electroless nickel solution composed of 60g/L nickel sulphate (NiSO4•6H2O) and 35g/L sodium hypophosphite (NaH2PO2•H2O) exhibits the highest deposition rate. Before 120 min deposition, the continuous deposition speed is all higher than the intermittent deposition. Afterwards, the continuous deposition speed tends to decrease, while the intermittent deposition rate tends to maintain a nearly fixed value or a little increase.
An increase in lead acetate concentration from 0 to 3ppm results in three types of representative electroless nickel bump structure, namely, the overgrowth edge, anisotropic, and pyramid. A decrease in pad size and an increase in pitch size favor the formation of pyramidal structure.

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