Papers by Keyword: Thermal Cycle Test (TCT)

Abstract: Segmented silicon detectors are widely used in modern high-energy physics (HEP) experiments due to their excellent spatial resolution and well-established manufacturing technology. However, in such experiments the detectors are exposed to high fluences of particle radiation, which causes irreversible crystallographic defects in the silicon material. Since 1990’s, considerable amount of research has gone into improving the radiation hardness of silicon detectors. One very promising approach is to use magnetic Czochralski silicon (MCz-Si) that has been found to be more radiation hard against charged hadrons than traditional Float Zone silicon material (Fz-Si) used in the current HEP applications. Other approaches include operating the devices at cryogenic temperatures and designing special detector structures such as p-type detectors or semi-3D detectors. In order to demonstrate that the developed technologies are suitable for the HEP experiments, it is necessary to extensively characterize the potentially radiation hard detectors. We have an excellent instrument for this, the Cryogenic Transient Current Technique (C-TCT) measurement setup, which is an effective research tool for studying heavily irradiated silicon detectors. With the C-TCT setup it is possible to extract the full depletion voltage, effective trapping time, electric field distribution and the sign of the space charge in the silicon bulk in the temperature range of 45-300 K. This article

Abstract: A three-dimensional finite element model of CMOS image sensor QFN packaging using ANSYS codes is developed to investigate the solder joint reliability under thermal cycle test. The predicted thermal-induced displacements were found to be very good agreement with the Moiré interferometer experimental in-plane deformations. The developed finite element model is then applied to predict fatigue life of Sn4.0Ag0.5Cu, Sn3.5Ag0.5Cu and Sn3.9Ag0.6Cu alloys based on JEDEC standard JESD22-A104. In order to save computational time and produce satisfactory results in the region of interest, an independent more finely meshed so-called submodel scheme based on cut-boundary displacement method is generated. The mesh density for different area ratio of refinery/coarse model was verified and the results were found to be good agreement with previous researches. The modified Coffin-Manson equation and strain energy density based equation are applied to evaluate the reliability of SnAgCu alloys. A series of comprehensive parametric studies were conducted in this paper.

Abstract: This paper demonstrates the thermal-induced mechanical problems resulted from various temperature profiles of reliability test for a system-in-package (SIP) assembly process. The package includes two flip chip mounted chips (underfilled), two memory CSPs, some passive SMDs and 4-layer BT substrate. The flip-chip specimen was taken and the Moiré Interferometry was used as methodology to verify the developed Finite Element Model and material property. It also shows that the developed finite element model is capable to simulate the JEDEC standard JESD22-A104 reliability thermal cycle test and then to predict solder fatigue life and to summarize design rules for thermal optimization of package based on the creep model and viscoplastic model of solder while the SIP package design is proceeded. Thermal design for SIP depends on the placement of FC chip (high power) and memory CSP components. Passive SMDs are also included to study the effect of thermal-induced stress. A series of comprehensive parametric studies were conducted in this paper.