Study of Metallization on Glass and Ceramic Substrates

近年來，3D 封裝晶片堆疊技術已備受各界矚目，但 3D 晶片封裝的技術困難度相當高，IC 設計方面也相當複雜，因此技術門檻較低的 2.5D 晶片封裝技術就因應而生。而中介層的作用是在 2.5D 晶片封裝內作為晶片間訊號之橋樑，因為玻璃有尺寸安定性高、電性絕緣與熱膨脹係數與矽相近等優勢，故已有文獻開始研究以玻璃中介層取代矽中介層。由於使用乾式製程進行金屬化的成本很高，因此本論文使用全濕式製程來取代乾式製程，然而要在光滑的玻璃上以濕式製程沉積具有附著力的金屬層非常困難，所以吾人使用化學自組裝法來提升玻璃與銅層間附著力，並在研究中發現使用金屬鹽類加上鹽酸作為矽烷自組裝層分散劑，能使自組裝層在玻璃表面分佈更加均勻，且經無電電鍍後能夠得到均勻亮面的銅層。最 後，能夠將金屬化後的兩種規格玻璃通孔 (Through Glass Vias, TGVs)，以蝶式填孔技術以無空洞或隙縫之結構完整填充。氮化鋁陶瓷基板已廣泛地應用於散熱方面，特別是高功率 LED 上。由於氮化鋁本身是絕緣材料，所以必須金屬化並沉積線路後才可以與 LED 進行封裝作為散 熱基材將熱導出。本論文中提出全濕式並在室溫下即可完成的氮化鋁金屬化製程，在無電電鍍製程中，吾人使用化學自組裝法將PdCl2 觸媒與氮化鋁基材接在一起。在自組裝前先針對氮化鋁基材進行 KOH 鹼蝕刻，此蝕刻步驟是使電鍍銅層有很好的附著力之關鍵。最後將矽烷吸附鈀製程與傳統錫鈀膠體製程互相比較，結果顯示使用矽烷吸附鈀製程所得到的電鍍銅層附著力比錫鈀膠體製程高二倍，並且經高溫熱信賴度測試後不會有銅泡產生，另外矽烷吸附鈀製程的鈀消耗量也比錫鈀膠體製程少五倍，因此化學接枝鈀製程之成本相對的較低。Recently, three-dimensional (3D) chip stacking has been paid significant attention. Interposer is a key connection component for the chip stacking, which serves as a bridge to connect multiple devices in z-direction. Glass has some significant advantages, such as excellent dimensional stability, excellent electrical insulation and coefficient of thermal expansion (CTE) close to silicon. However, the metallization cost of the glass interposer by using a dry process is too high. Therefore we use a wet process to replace the dry process in order to reduce the overall process cost. Wet process is a fast and low cost technique for a substrate metallization. However, it’s difficult to deposit a metal layer onto a smooth glass substrate through a wet process. This paper presents a method to im-prove the adhesion between a glass wafer and a copper layer without roughening the glass surface. This paper presents a chemical grafting step to improve the adhesion between a glass wafer and a copper layer without roughening the glass surface. The process includes a chemical grafting step for adsorbing metal ions onto the glass surface and a specific distribution promoter for improving the uniformity of the chemical grafting layer. Fol-lowing the catalyst coating and electroless deposition, the metallized glass wafer looks like a copper mirror. The copper-metallized TGVs (Through Glass Vias) are fully filled with copper by using butterfly technology (BFT) of copper electroplating. These results show that the metallization and electroplating processes for glass interposer fabrication has been successfully developed. AlN substrate has been extensively employed for heat dissipation, especially for high power light emitting diode (LED) However, AlN substrate is an electric insulator, so it needs to be metallized in order to serve as an electric circuit carrier as well as a heat con-ductor for LED packaging. Herein, we propose a wet and room temperature process for metallizing the AlN substrate. The wet metallization process includes copper electroless deposition and copper electroplating. The catalyst used for the copper electroless depo-sition is PdCl2, which is chemically grafted onto the AlN surface. The chemical grafting agent is 3-(2-aminoethylamino) propyltrimethoxysilane (APTMS). Before the chemical grafting step, an etching step in KOH solution is critical for good adhesion of the plated copper layer. A comparative test of copper layer adhesion performed by the chemically grafted Pd and a commercial Sn/Pd colloid was carried out, showing that the performance of the chemically grafted Pd process is much better than that of the commercial Sn/Pd colloid process, including no copper blister formation at high temperature and low Pd consumption.中文摘要 i Abstract ii 目錄 iv 圖目錄 vi 表目錄 xiii 壹、文獻回顧 1 一、晶片堆疊發展 . . . . . . . . 1 (一)、銅製程 . . . . . . . . . .1 (二)、矽通孔 (Through Silicon Vias) . . . . 3 (三)、中介層 (Interposer) . . . . . . . .7 二、玻璃基板表面金屬化 . . . . . . . 25 (一)、表面改質法 . . . . . . . . . .25 (二)、分子自組裝接枝法 . . . . . . . 31 三、LED 陶瓷散熱基板表面金屬化 . . . . . . 40 (一)、LED 散熱基板 . . . . . . . . . 40 (二)、陶瓷基板表面金屬化 . . . . . . . . 44 四、電鍍與電鍍添加劑 . . . . . .50 (一)、電鍍添加劑 . . . . . . . . . 50 (二)、電鍍方法 . . . . . . . . . 56 (三)、通孔電鍍 . . . . . . . . .57 五、無電電鍍 . . . . . . . . . .74 (一)、無電電鍍銅的歷史與發展 . . . . . . . 74 (二)、無電電鍍銅液組成與特性 . . . . . . . 76 (三)、無電電鍍銅反應機制 . . . . . . . . 79 六、田口法 . . . . . . . . . . . 80 七、研究動機 . . . . . . . . 82 貳、實驗藥品、裝置、步驟 83 一、藥品 . . . . . . . . . . .83 二、裝置 . . . . . . . . . . . .85 三、步驟 . . . . . . . . . . . 93 參、玻璃基板金屬化 96 一、玻璃金屬化銅層 . . . . . .96 二、IR 與 XPS 能譜分析 . . . . . 110 三、分散劑對矽烷分子自組裝的影響 . . . . . . 116 四、不同金屬鹽類作為分散劑之效果 . . . . . . . 129 五、反應溫度、時間與矽烷濃度對矽烷分子自組裝的影響 . . 135 六、結論 . . . . . . . . . . . . 144 肆、LED 陶瓷散熱基板金屬化 146 一、AlN 陶瓷基板金屬化 . . . . . . . . . 146 二、結論 . . . . . . . . . . 164 伍、以蝶式填孔技術填充中介層之研究 165 一、玻璃與陶瓷中介層之填孔 . . . . . . .165 二、結論 . . . . . . . . . . . 170 陸、總結 171 染、未來研究項目 173 捌、參考文獻 17