Study of Metallization on Glass and Ceramic Substrates

• Main Authors: Shao-Ping Shen, 沈紹平
• Other Authors: 竇維平
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/40575617155574188680

博士 === 國立中興大學 === 化學工程學系所 === 102 === 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.