September 19-20 International Student Orientation September 22 New Student check-In for Undergraduates September 22-29 New Student Orientation for Undergraduates September 23 New Student Check-In for Graduates September 23-27 New Student Orientation for Graduates September 26 Undergraduate Academic Standards and Honors Committee – 1:00 p.m. September 27 Undergraduate Academic Standards and Honors Committee Appeals– 1:00 p.m. September 30 Rosh Hashanah – classes excused October 1 Beginning of instruction 8:00 a.m. October 18 Last day for adding courses and removing conditions and incompletes October 30Midterm examination period November 5 November 11 Midterm deficiency notices due 9:00 a.m. November 20 Last day for dropping courses, exercising pass/fail option, and changing sections November 21Registration for winter term 2019-20 December 6 November 28-29 Thanksgiving (Institute holiday) December 6 Last day of classes Last day to register for winter term 2019-20 without a $50 late fee December 7-10 Study period December 11*-13 Final examinations, fall term 2019-20 December 13 End of fall term 2019-20 December 14Winter recess January 5 December 18 Instructors' final grade reports due 9:00 a.m. *First due date for final examinations

カリフォルニア工科大学 (California Institute of technology) 滞在記

A comprehensive review of big data analytics throughout product lifecycle to support sustainable smart manufacturing: A framework, challenges and future research directions

Automatic wire bonding is a highly mature, cost-efficient and broadly available back-endprocess, intended to create electrical interconnections in semiconductor chip packaging. Modern production wi ...

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Unconventional applications of wire bonding create opportunities for microsystem integration

A review of recent advances in power electronic packaging is presented based on the development of power device integration. The presentation will cover in more detail how advances in both semiconductor content and power advanced package design and materials have co-enabled significant advances in power device capability during recent years. Extrapolating the same trends in representative areas for the remainder of the decade serves to highlight where further improvement in materials and techniques can drive continued enhancements in usability, efficiency, reliability and overall cost of power semiconductor solutions. Along with new power packaging development, the role of modeling is key to assure successful package design. An overview of the power package modeling is presented. Challenges of power semiconductor packaging and modeling in both next generation design and assembly processes are presented and discussed.

Trends of Power Electronic Packaging and Modeling

Due to the rapid development of IC technology the traditional packaging concepts are making a transition into more complex system integration techniques in order to enable the constantly increasing demand for more functionality, performance, miniaturisation and lower cost. These new packaging concepts (as e.g. system in package, 3D integration, MEMS-devices) will have to combine smaller structures and layers made of new materials with even higher reliability. As these structures will more and more display nano-features, a coupled experimental and simulative approach has to account for this development to assure design for reliability in the future. A necessary “nano-reliability” approach as a scientific discipline has to encompass research on the properties and failure behaviour of materials and material interfaces under explicit consideration of their micro- and nano-structure and the effects hereby induced. It uses micro- and nano-analytical methods in simulation and experiment to consistently describe failure mechanisms over these length scales for more accurate and physically motivated lifetime prediction models. This paper deals with the thermo-mechanical reliability of microelectronic components and systems and methods to analyse and predict it. Various methods are presented to enable lifetime prediction on system, component and material level, the latter promoting the field of nano-reliability for future packaging challenges in advanced electronics system integration.

Lifetime modelling for microsystems integration: from nano to systems

In this paper, a transient non-linear dynamic finite element framework is developed, which integrates the wire bonding process and the silicon devices under the bond pad. Two major areas are addressed: one is the impact of the assembly 1/sup st/ wire bonding process and another one is the impact of device layout below the bond pad. Simulation includes the ultrasonic transient dynamic bonding process and the stress wave transferred to the bond pad device and silicon in the 1/sup st/ bond. The Pierce strain rate dependent model is introduced to model the impact strain hardening effect. Ultrasonic amplitude and frequency are studied and discussed for the bonding process. In addition, different layouts of device metallization under the bond pad are analyzed and discussed for the efforts to reduce the dynamic impact response of the bond pad over active (BPOA) design. Modeling discloses the stress and deformation impacts to both wire bonding and pad below the device with strain rate, different ultrasonic amplitudes and frequencies, different friction coefficients, as well as different bond pad thickness and device layout under the pad. The residual stress, after cooling down to a lower temperature, is discussed for the impact of substrate temperature.

Thermosonic wire bonding process simulation and bond pad over active stress analysis

3D Modeling of electromigration combined with thermal–mechanical effect for IC device and package

A pattern clustering algorithm is proposed in this paper as a statistical quality control technique for diagnosing the solder paste variability when a huge number of binary inspection outputs are involved. To accommodate this goal, a latent variable model is first introduced and incorporated into classical logistic regression model so that the interdependencies between measured physical characteristics and their relationship to the final solder defects can be explained. This probabilistic model also allows a maximum-likelihood principal component analysis (MLPCA) method to recognize the dimension of systematic causes contributing to solder paste variability. The correlated measurement variables are then projected onto the reduced latent space, followed by an appropriate clustering approach over the inspected solder pastes for variation interpretation and quality diagnosing. An application to a real stencil printing process demonstrates that this method facilitates in identifying the root causes of solder paste defects and thereby improving PCB assembly yield.

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A Data Mining Algorithm for Monitoring PCB Assembly Quality

This paper investigates the impact of die attach process, including a tilted die, on the power cycling and thermal cycling performance for a discrete style TO220 package. A non-linear material model for die attach solder material is introduced, and an advanced finite element methodology is developed to target the coupled thermal-mechanical problem. For power cycling, a transient thermal analysis is presented, that will show the thermal propagation as the power turned on and off, and the resulting temperature gradients. Then the authors used the cyclic transient temperature loads to apply to the model for the non-linear cycle stress analysis. For thermal cycling, the cycle temperature is directly applied to the model. The parameterized models for different die size and thickness' are simulated and analyzed. Finally discussion and conclusion regarding this study are presented.

Timwah Luk

Papers

Thermosonic wire bonding process simulation and bond pad over active stress analysis

Trends of Power Electronic Packaging and Modeling

3D Modeling of electromigration combined with thermal–mechanical effect for IC device and package

A Data Mining Algorithm for Monitoring PCB Assembly Quality

Impact of the die attach process on power & thermal cycling for a discrete style semiconductor package