PVD systems for advanced packaging applications

Physical vapor deposition (PVD) technology plays an important role in the advanced packaging (AP). It has a direct impact to the performance of final products. For AP application, e.g. bumping, fan-out and CIS, a clustered PVD approach is required to ensure a low contact resistance (Rc) and better film properties for better device performance. A clustered PVD platform consists of several modules including a transfer module, a Degas module, a Pre-clean module and PVD deposition modules. In this paper, we are going to report the developments of a clustered PVD system, the NAURA Polaris PVD for AP applications. NAURA Polaris PVD system is widely used in many advanced packaging processes. There are significantly different type of wafer in AP fields due to different applications, e.g. SOG wafers, EMC wafers, glass wafers, thin wafers, taiko wafers. It is a big challenge to handle wafers with a large warpage. Thus it is required that the transfer module must have a strong capability to handle different wafer type and to detect failures. Wafers with PI/PBO/EMC (Polyimide/ Poly-p-phenylene benzobisoxazole/ Epoxy Molding Compound) materials require longer time degas process to ensure full outgasing. However, longer degas process results in lower throughout. Therefore it is necessary to develop a multi-wafer degas chamber to ensure competitive throughput. Proper temperature control(proper temperature and proper time) is critical for better Rc uniformity. An ICP Pre-clean module with stable plasma is developed to remove organic residues and native oxide on metal surface efficiently. To avoid re-oxide on metal surface, low process temperature is required. Furthermore, low process temperature is also capable to yield a better Rc performance. The PVD deposition module has wide process windows on film stress, uniformity, resistance and film crystalline phase. Thus it is easier to achieve a stable optimized process condition that improve device reliability.