隨著科技日新月異，積體電路日漸變小以及隨著電子元件尺寸的微小化，封裝技術中三維整合電路利用晶體的堆疊方式達到封裝尺寸微小化之目的。而製程中必須透過Sn銲料將電子元件以及待組裝之基板互相連接在一起，在長期熱時效的作業中將會導致Cu與Sn銲料互相擴散，導致界面處會形成脆性之金屬間化合物，並降低銲接點的可靠性。
為了降低金屬間化合物形成，在本實驗中使用高熵合金薄膜作為擴散阻障層，若將其用運用在半導體或各種製程的匹配性，薄膜的平坦度是元件堆疊的基本要求。而高熵合金系統中以過渡金屬元素所組成之系統最為成熟，本實驗選用相穩定高且呈現單一FCC單一固溶體結構之Al0.5CoCrFeNi2高熵合金薄膜。
然而在不同工作參數下以濺鍍法製備之Al0.5CoCrFeNi2高熵合金薄膜，會具備不同結晶性、機械性質及表面粗糙度，且根據擴散阻障層的條件，薄膜與接觸材料的界面平整性與粗糙度會對結構及電性產生影響，因此本實驗將Al0.5CoCrFeNi2高熵合金薄膜進行化學機械拋光，達到表面平坦化，而化學機械拋光是一種結合化學反應以及機械研磨來達到晶圓平坦化的製程。
首先確認Al0.5CoCrFeNi2高熵合金薄膜適合在何種拋光液中進行實驗，透過兩款拋光液進行高熵合金薄膜化學機械拋光，結果顯示，含有HNO3氧化劑之ESA220的平坦化效果優於含有FeCl3溶液之ESA207，表面粗糙度下降幅度較高，接著進行拋光時間參數之設計，於拋光時間5分鐘，得到本實驗最大之材料移除率，然而在固定ESA220拋光液、下壓力50 g/cm2、轉速40 rpm、拋光時間5分鐘，得到下降幅度最多的最佳表面粗糙度2.137 nm，而在本實驗結晶性佳之薄膜擁有較佳之機械性質，在進行化學機械拋光後，獲得最高之表面粗糙度下降值20%。

With the rapid development of technology, integrated circuits are getting smaller, the three-dimensional integrated circuit in packaging technology uses the stacking method of crystals to achieve the purpose of miniaturizing the package size. In the process, the electronic components and the substrate should be connected to each other through soldering. During the long-term thermal aging operation, copper and solder will diffuse together, resulting in the formation of intermetallic compounds at the interface and reduce the reliability of solder joints.
In order to reduce the intermetallic compounds, high-entropy alloy film has been used as a diffusion barrier layer in this experiment. If it is used in semiconductors industry, the flattened of the film is a basic requirement for device stacking. In this experiment, the Al0.5CoCrFeNi2 thin film with high phase stability and FCC single solid solution structure was selected.
However, Al0.5CoCrFeNi2 thin films prepared by sputtering under different working parameters, they have different crystallinities, mechanical properties and surface roughness, according to the conditions of the diffusion barrier layer, the interface between the thin film and the contact material must be flat, roughness will affect the structure and electrical properties, so in this experiment, chemical mechanical polishing is used to achieve surface flattening.
First, confirm which slurry is suitable for Al0.5CoCrFeNi2 thin film, the results show that the flattening effect of ESA220 containing HNO3 oxidant is better than ESA207 slurry containing FeCl3 solution. When the polishing time is 5 minutes, and the maximum material removal rate in this experiment is obtained. At 40 rpm, down force 50 g/cm2, the result shows the optimized surface roughness Sa 2.137 nm, and the thin film with good crystallinity has better mechanical properties that obtains the highest surface roughness decrease by 20% after chemical mechanical polishing.

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