覆晶封裝結構中熱老化對介面間缺陷之影響

Effect of Thermal Aging on Defects between Interfaces in Flip Chip Packaging Structure

洪金泳(Jin-Yong Hong)

指導教授 ： 鄭桐華

國立虎尾科技大學/工程學院/材料科學與綠色能源工程研究所/碩士(2012年)

https://doi.org/10.6827/NFU.2012.00199

摘要

本文研究覆晶封裝(Flip chip)試片在熱老化試驗中之介面缺陷現象。探討高溫熱老化導致各材料間的熱擴散，及具脆性且較低導電性之介金屬化合物(Intermetallic compounds, IMC)生成，與介面裂縫(Cracks)之生成，進一步探討整個試片應變值變化之影響，與電路電阻變化率之關係。實驗以兩種不同厚度之錫球底層金屬層(Under bump metallurgy, UBM)進行比較。
實驗結果得知，在經過300小時及500小時、150℃熱老化後Cu3Ni1.5Au0.2之壓縮應變值小於Cu2Ni1Au0.2，因其翹曲情形小所以造成Cu3Ni1.5Au0.2有顯著的裂縫產生。翹曲情形大的現象使覆晶封裝結構電路之電阻變化率(0.1ΔR/(R+0.1)2)提高，且封裝結構內側電路之電阻變化率高於外側電路。在顯微結構觀察中，兩組試片在熱老化過程皆有發現IMC的產生，但是與UBM層的厚度並無顯著的關係。

關鍵字

覆晶封裝 ； 介金屬化合物 ； 錫球底層金屬層

並列摘要

This study presents an investigation on thermal aging effects in flip-chip structures by examining thermal diffusion between various materials and the growth of brittle intermetallic compounds (IMC) with low conductivity. Thermal aging experiments are conducted on flip chips to examine the consequent interface cracking between materials. Furthermore, changes in strain and circuit resistivity changes are discussed between specimens with two thicknesses of the under bump metallurgy (UBM).
The results show that compression strain of the flip-chip structure with Cu3Ni1.5Au0.2 UBM is less than that of Cu2Ni1Au0.2 UBM after 300 and 500 h of thermal aging at 150℃. The cracks obviously exist in the flip-chip UBM package structure with Cu3Ni1.5Au0.2 because its deformations are small. Furthermore, the larger deformations and strains cause greater changes in circuit resistivity. Microstructure observations show that both specimens exhibit IMC under thermal aging conditions, although IMC thickness is unrelated to UBM thickness.

並列關鍵字

Flip chip ； IMC ； UBM

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