MANUFACTURING QUALIFICATION FOR THE LATEST GAMING DEVICE WITH Pb-FREE ASSEMBLY PROCESS
Authors: Ding Wang Chen, Ph.D., Alex Leung, Alex Chen Raul Rodriquez, Paul P.E. Wang, Ph.D., and Michael Miller Company: Celestica and XBOX, Microsoft Corporation Date Published: 1/31/2007
Pan Pacific Symposium
Abstract: With the implementation of RoHS, Pb-free assembly processes are being gradually introduced throughout the electronics industry. Unlike the Sn/Pb process, which has been run for more than 40 years in EMS industry, Pb-free process is relatively new. In order to ensure the Pb-free products with good quality & reliability, process qualification is essential in the product introduction stage. This paper will address a comprehensive qualification on a gaming device with Pb-free assembly process. Increased computational speed and graphically virtual reality of gaming device pushed the assembly design denser and thermally more challenging. In the assembly, both SMT and wave soldering processes are employed in the massive manufacturing processes of this Pb-free product. The process qualifications are verified by employing different techniques, 2D X-ray, C-SAM, micro-cross sectioning, SEM, solder joint shear, and dye & pry tests. Solder joint wetting quality, joint strength, sustainability of BGA joints to mechanical stress, resistant to Pb-free high temperature of MSL thermal sensitive components and inter-metallic layer formation in solder joint are evaluated. Results from the evaluation will be described in detail. Mechanical stress in each stage is also evaluated in each of the process flow from the front end to the back end in the manufacturing floor. To assist the design improvement of the product, conventional Highly Accelerated Life Testing (HALT) is widely used in the Design Verification Test (DVT) stage to derive system operation limit in the early stage. Reliability performance of this latest gaming device is tested with Accelerated Thermal Cycling (ATC). Thermal profile temperate ranges from 0 to 100 degrees Celsius with ramp up/down rate of 13oC/min for 3500 cycles. Functional test is performed for all boards in-between every 500 cycles. Test results are used in a proactive manner to establish a close-loop process quality control system. Key words: Pb-free process, Process qualification, Failure analysis, Reliability test.