臺灣博碩士論文加值系統

轉移成型係IC塑膠元件的封裝方式之一，封裝是將封膠樹脂熔化後擠入模穴，封裝過程中，可能發生金線偏移、氣泡、或短射等缺陷而導致IC成品的失敗，其中金線偏移乃指在封裝過程中，連接晶片與導線架間之金線產生永久之變形；隨著IC元件的輕薄化及多腳化的趨勢，金線間距變小，流動負荷很容易造成過大的金線偏移，使得相鄰的金線發生接觸造成短路，甚至金線因過度拉扯斷裂而形成斷路現象，由於金線偏移直接影響IC產品的良率，因此如何避免封膠過程中金線偏移對產品的影響，成為目前重要的課題。
本文乃整合模流數值分析、金線黏塑性試驗、及有限元素分析等方法計算金線的偏移量。首先以C-MOLD模流分析軟體模擬封膠過程的流動情形，藉此設計符合流動平衡之DIP28L最佳化封膠模具。其次進行金線黏塑性試驗以分析金線於室溫及封膠溫度（175℃）下之應力-應變關係，並探討應變速率與溫度對黏塑性行為的影響，及尋求黏塑性模型所需的材料參數，以便建立金線在不同的溫度下之黏塑性本構理論模型。最後使用ABAQUS有限元素分析軟體，配合金線的流動負荷以及金線的黏塑性本構模型，計算金線的黏塑性偏移，此計算流程可作為模具最佳化設計的依據。

Molding is a very important step during the packaging processes of microelectronics. The gold wires between the chip pads and leadframe deform under the action of flow loading of molten transfer molding compound. Significant permanent displacements of the wires, which are termed “wire sweep”, may occur if deformation is inelastic during cooling to room temperature. Since the advances of micro-electronics technology, the power of IC devices is improved as the physical dimensions shrink. This results in the smaller distance between gold wires. If the wire sweep is sufficiently large, it may cause a short circuit due to touching of adjacent wires. This phenomenon may be one of the most important problems in the IC package.
In order to estimate the wire sweep, the knowledge of flow load, viscoplasticity of the wire, as well as finite element analysis are necessary. To develop viscoplasticity theory, experiments of rate change and stress relaxation of gold wires are performed at room temperature and 175ºC. Experimental results at both temperatures are employed to establish the viscosity functions and temperature-dependent elastic-viscoplastic constants of a wire, respectively. Because the flow load of the molten molding compound during cavity filling stage are quite different, C-MOLD package will therefore be applied to investigate the suitable flow load. Finally, the ABAQUS finite element package, together with the flow loading and viscoplasticity theory of the wire, are employed to estimate the wire sweep of the wire bond in DIP28L packages.

摘要 ……………………………………………………………………………………Ⅰ
誌謝 ……………………………………………………………………………………Ⅱ
目錄 ……………………………………………………………………………………..Ⅲ
表目錄 …………………………………………………………………………………Ⅵ
圖目錄 …………………………………………………………………………………Ⅳ
符號說明 ………………………………………………………………………………Ⅹ
第一章 緒論 ……………………………………………………………………………1
1-1 前言 …………………………………………………………………………….1
1-2 研究背景與動機 ……………………………………………………………….2
1-3 研究目的 ……………………………………………………………………….3
1-4 本文架構 ……………………………………………………………………….3
第二章 文獻回顧 ………………………………………………………………………..5
2-1 金線偏移的研究 ……………………………………………………………….5
2-2 黏塑性理論模型的研究 ……………………………………………………….6
第三章 封膠材模流分析 ………………………………………………………………..8
3-1 研究目的 …………………………………………………………………….…8
3-2 封膠材料之特性 …………………………………………………………….…8
3-3 最佳化流動平衡之模流分析的流程與規劃 ………………………………...10
3-4 模流分析之基本假設 ………………………………………………………...11
3-5 封膠材料的黏度、固化反應程度公式之應用 ……………………………….13
3-5-1 固化反應程度計算公式（degree of cure equation）之應用 ……………13
3-5-2 黏度計算公式（degree of viscosity equation）之應用 ………………….13
3-6 金線之局部流場的速度、溫度與拖曳力計算公式之應用 ………………….14
3-6-1 金線之局部流場的速度、溫度計算公式之應用 ……………………..14
3-6-2 金線拖曳力轉換公式（Drag-force calculation equation）……………...15
3-7 金線黏塑性偏移之計算方式-ABAQUS ……………………………………..16
3-8 模流分析之步驟與方法 ……………………………………………………...16
3-8-1 封膠模具的設計 ………………………………………………………16
3-8-2 封膠材料的選擇 ………………………………………………………17
3-8-3 轉移成型機之控制條件的設定 ………………………………………18
3-9 模流分析之結果……………………………………………………………….18
第四章 金線黏塑性實驗與有限元素分析 ……………………………………………19
4-1 實驗目的 ……………………………………………………………………...20
4-2 實驗之流程與規劃 …………………………………………………………...20
4-3 實驗設備及實驗裝備 ………………………………………………………...21
4-4 實驗控制軟體的設定 ………………………………………………………...23
4-5 實驗之步驟與方法 …………………………………………………………...23
4-5-1 金線試片之準備 ………………………………………………………24
4-5-2 實驗條件 ………………………………………………………………24
4-5-3 實驗步驟 ………………………………………………………………25
（1） 不同的等應變速率實驗 ………………………………………..26
（2） 應變速率改變實驗 ……………………………………………..26
（3） 應力鬆弛實驗 …………………………………………………..27
4-6 黏塑性理論模型參數之建立 ……………………………………………….27
4-7 有限元素分析之流程與規劃 ………………………………………………...29
4-8 有限元素分析之基本假設 …………………………………………………...30
4-9 有限元素分析之步驟與方法 ………………………………………………...30
4-10 金線黏塑性實驗及有限元素分析之結果 ………………………………...34
第五章 綜合討論與未來發展 …………………………………………………………37
5-1 封膠材模流分析部份 ………………………………………………………...37
5-2 金線黏塑性實驗與有限元素分析部分 ……………………………………...38
5-3 未來發展 ……………………………………………………………………...40
參考文獻 ………………………………………………………………………………..88
附錄 ……………………………………………………………………………………..93
英文摘要 ……………………………………………………………………………..101
自述 ……………………………………………………………………………………102

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