Behavior of Copper Contamination for Ultra-Thinning of 300 mm Silicon Wafer down to <5 μm

Bumpless interconnects and ultra-thinning of 300 mm wafers for three-dimensional (3D) stacking technology has been studied [1, 2]. In our previous studies, wafer thinning effect using device wafers less than 10 μm was investigated [3, 4]. There was no change for the retention time before and after thinning even at 4 μm in thickness of DRAM wafer [5]. In this study, the behavior of Cu contamination on an ultra-thin Si stacked structure was investigated. Thinned Si wafers were intentionally contaminated with Cu on the backside and 250 °C of heating was carried out during the adhesive bonding and de-bonding processing. An approximately 200 nm thick damaged layer was formed at the backside of the Si wafer after thinning process and Cu particle precipitates ranged at 20 nm were observed by cross-sectional transmission electron microscopy (X-TEM). With secondary ion mass spectrometry (SIMS) and EDX analyses, Cu diffusion was not detected in the Si substrate, suggesting that the damaged layer prevents Cu diffusion from the backside

Remote experiment with WEST from ITER Remote Experimentation Centre

Remote experiment with WEST tokamak in CEA Cadarache from ITER Remote Experimentation Centre (REC) inRokkasho had been successfully carried out under the agreement between the Government of Japan and theEuropean Atomic Energy Community for the joint implementation of the Broader Approach (BA) activities in thefield of fusion energy research. The WEST and the REC sites were connected with the international broadbandnetwork for science and education of SINET, GÉANT and RENATER. Due to a long distance over 10,000 km oftwo sites, the latency was about 200 ms (round trip time) in total via the direct line between EU and Japan ofSINET5. Based on the communication between local and remote participants, plasma discharges were success-fully executed repeatedly according to the pulse schedule produced by remote Session Leader after the approvalby Engineer in Charge on WEST site. Intershot analyses were successfully executed during the pulse interval onan analysis server prepared in Partners network in the WEST for external collaborator. Full function required forthe remote experiments were successfully demonstrated in the large size tokamak facility, WEST. For remoteparticipation of ITER, however, it is expected that the amount of experimental data and the number of remoteparticipations will become very large. Distributed database system based on data replication using high-speeddata transferring method and distributed computing resources in local and remote sites are proposed as apossible solution in ITER