Papers by kuan-jung chung
Task failure prediction for wafer-handling robotic arms by using various machine learning algorithms
Measurement and Control, 2021
Industries are increasingly adopting automatic and intelligent manufacturing in production lines,... more Industries are increasingly adopting automatic and intelligent manufacturing in production lines, such as those of semiconductor wafers, optoelectronic devices, and light-emitting diodes. For example, automatic robot arms have been used for pick-and-place workpiece applications. However, repairing automatic robot arms is time-consuming and increases the downtime of equipment and the cycle time of manufacturing. In this study, various machine learning (ML) models, such as the general linear model (GLM), random forest, extreme gradient boosting, gradient boosting machine, and stacked ensemble, were used to predict the maximum Cartesian positioning shift (i.e. the maximum eccentric distance) in the next handling time period (e.g. 1 min). A charge-coupled-device-based fault diagnostic system was developed to measure the critical positions of the robotic arm when transferring wafers. A novel data augmentation method was used to determine the correlation parameters in the dataset for the ...
Effect of Strain Rates on the Mechanical Behavior of Cu Thin Films of Various Thicknesses
Applied Mechanics and Materials, 2013
The objective of this study is to investigate the mechanical behavior of copper thin film with di... more The objective of this study is to investigate the mechanical behavior of copper thin film with different thicknesses subjected to varying strain rates. A micro-force tensile testing machine (MTS Tytron 250) was used to test the polyimide samples coated with different thicknesses of copper (500 nm, 750 nm, 1000 nm, and 1500 nm). The experiments were conducted by applying test vehicles to different strain rates (1.6×10-4 s-1, 1.6×10-3 s-1, and 1.6×10-2 s-1). The experimental results showed the strain rate and the thickness have obvious influence upon the mechanical properties of Cu thin film. The yield stress increases as increasing the strain rate or decreasing the thickness of Cu film. For considering the strain rate sensitivity m, the strain rate sensitivity m is found that it increases as decreasing the thickness to imply that Cu film has high strain-rate response at low thickness.
Reliability Tests of a RFID-based Lock for Power Meter Applications
A novel lock (seal), combined Radio Frequency Identification (RFID) techniques with a smart mecha... more A novel lock (seal), combined Radio Frequency Identification (RFID) techniques with a smart mechanism, has been developed to improve the anti-thief ability of the traditional mechanical lock (seal) and RFID-based one that we developed in previous work. The reliability validation tests present that RFID locks past all required test conditions including mechanical and environmental tests to demonstrate that RFID is suitable for the defined conditions in use. Furthermore, a thermal cycling test was performed to evaluate the Lifetimes of RFID-based locks. Norris-Landzberg accelerated life model is applied. The results show that the mean life of RFID locks is longer than the required 5 years, and there are 24 RFID locks to fail among 5 years when employing 1 million of them in the market.
The solder joint reliability assessment of a wafer level CSP package
A WLCSP package consists of 2.2 × 2.2 mm2 silicon die, polyimide-based substrate, and 5 × 5 array... more A WLCSP package consists of 2.2 × 2.2 mm2 silicon die, polyimide-based substrate, and 5 × 5 array of solder balls was used as the test vehicle to evaluate its solder joint reliability. Both package level tests with respect to precondition test, temperature cycling test, unbiased highly accelerated stress test (UHAST), and high temperature storage life (HTSL) test and board level tests regarding temperature cycling test have been included in the test plan. Two different lead free solder ball materials (SAC1205 vs. SAC105), under bump metallurgy (Ti/NiV/Cu vs. plated Cu), and die thicknesses (406 μm vs. 356 μm) were assessed. The test results for the package level assessment present that the test vehicle past criteria for all of these required tests. The test results of temperature cycling (-40°C ~125°C) for the board level assessment show that these controlled variables have unlike performance in the solder joint reliability (SJR) of the WL-CSP package. The SAC105 shows better solder joint reliability performance than that of SAC1205 to provide 13 % improvement in characteristic life (Weibull distribution). The thick die (406 μm) shows statistically better SJR performance than that of thin die (356 μm) to sustain 10% increase in characteristic life (Weibull distribution). On the other hand, standard Ti/NiV/Cu UBM presents statistically equivalent SJR performance as plated Cu in characteristic life. As the results, package design factors of the solder alloy and die thickness play obvious roles in solder joint reliability compared to the factor of UBM. Generally speaking, the WL-CSP package presents appropriate solder joint reliability according to the test results.
The investigation of modified Norris-Landzberg acceleration models for reliability assessment of Ball Grid Array packages
Norris-Landzberg acceleration model, only applying the conditions of the temperature cycling test... more Norris-Landzberg acceleration model, only applying the conditions of the temperature cycling tests such as temperature range, maximum of temperature and cycle times, has been widely using to predict the lifetimes of electronic packages since 1969, due to its simplicity not considering complex damage information such as stress-strain relationships. During the last few years, a number of researches have shown that
Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2010
Three new microbridge structures, which are able to form lateral-and-vertical links simultaneousl... more Three new microbridge structures, which are able to form lateral-and-vertical links simultaneously in the metal layers of ICs for low resistance interline connections, are presented in order to solve the issue of undesirable links occurred after laser processing. Comprehensive laser processing experiments were performed to verify these designs. The results show that there exits different performance (electrical resistances) and laser energy windows for these structures. There is no perfect design so that one structure (S2) is selected as an optimal structure by considering of the production reality with respect to the highest yield first and then wider energy window, though it only presents the second low resistance.
In the latest generation of wire bonders, the bond cycle is so short that the ward electrode of t... more In the latest generation of wire bonders, the bond cycle is so short that the ward electrode of the electronic flame off (EFO) discharge used to heat and melt the wire is fixed to side. Because no more than a few ppm defects in ball bonds can be tolerated, any tiny factor such as the EFO ward electrode wear and surface pollution which effect the ball formation will be concerned. In this paper, the EFO ward electrodes of different wear rates and surface pollution were set up to wire bonder and then performed bonding processes. Two typical methods, wire pull and ball shear tests, were used to judge the wire bonding quality. From the experimental results, wire bonding quality descend when the EFO ward electrode wore and surface was polluted. The lowest wire pull and ball shear value have approached to actual production lines standards, and some even lower than specification. It is concluded if EFO ward electrode wear is controlled by adjusting discharge gap and cleaning the surface of electrode regularly, wire bonding quality will not get worse. Therefore a multi-function detectable tool is successfully designed not only to check up the wear and lifetime of electrode, but also to clean its surface. The solution was lately executed in actual production lines, and had been proved effectively.
The impact of lead-free soldering on electronics packages
Microelectronics International, 2001
The critical properties of power devices are high reverse breakdown voltage and low forward ON st... more The critical properties of power devices are high reverse breakdown voltage and low forward ON state resistance, Ron,sp, during high forward current density operation. Both of these parameters are very sensitive to temperature. Nowadays silicon carbide (SiC) and GaAs are two most important materials for power device applications. SiC has been widely accepted as being superior to GaAs because it has much higher electric breakdown field, saturated electron drift velocity and thermal conductivity. In this work, the electrical performance and reliability of SiC Schottky diodes (SD) are evaluated and compared to commercially available GaAs SDs. High temperature device characterization has been performed. The specific ON resistance Ron,sp was found to increase with temperature according to T0.72 dependence for GaAs and T1.89 for SiC. The strong temperature dependence of Ron,sp is consistent with phonon scattering theory. Based on Baliga's figure-of-merit (BFOM) model, our result shows that under higher operating temperature (> 210 °C) the GaAs devices have lower Ron,sp than SiC, thus, it may be preferable to use GaAs over SiC for some high temperature power applications.
A Continuous-Time Laser Programmable Analog Array for Radiation Environments
... 5001 Indian School Road NE Albuquerque, NM [email protected] Ji Luo, Joseph B. Bernstein,... more ... 5001 Indian School Road NE Albuquerque, NM [email protected] Ji Luo, Joseph B. Bernstein, J. Ari Tuchman, Hu Huang, Kuan-Jung Chung University of Maryland 2100 Marie Mount Hall ... FBFTFN 4 inputs/4 outputs 4 PRAs 4 PCAs Lines in read = 8 track buses ...
Comparison of silicon carbide and GaAs Schottky diode
The critical properties of power devices are high reverse breakdown voltage and low forward ON st... more The critical properties of power devices are high reverse breakdown voltage and low forward ON state resistance, Ron, during high forward current density operation. Both of these parameters are very sensitive to temperature. Nowadays silicon carbide (SiC) and GaAs are two most important materials for power device applications. SiC has been widely accepted as being superior to GaAs because it has much higher electric breakdown field, saturated electron drift velocity and thermal conductivity. In this work, the electrical performance and reliability of SiC Schottky diodes (SD) are evaluated and compared to commercially available GaAs SDs. Accelerated life tests (ACT) and high temperature device characterization have been performed. The activation energy and mean time to failure (MTTF) were calculated. Our results show that the strong temperature dependence of Ron is consistent with phonon scattering theory. Based on Baliga's figure-of-merit (BFOM) model, our result shows that under higher operating temperatures (>260°C) the GaAs devices have lower Ron than SiC, thus, it may be preferable to use GaAs over SiC for high temperature power device applications
Experimental Study for Low Resistance Interline Connections Using Pulsed Laser Techniques
In this paper, experimental study was performed to evaluate the design of new four interline conn... more In this paper, experimental study was performed to evaluate the design of new four interline connect structures. The energy windows as well as optimal laser spot size were obtained from the experimental results, which show the minimum link resistance and highest yield. Accordingly above criteria, a best structure would be estimated
While interest, availability and use of FPAAs have grown, FPAAs still have not achieved the same ... more While interest, availability and use of FPAAs have grown, FPAAs still have not achieved the same success as FPGAs in the digital domain. This results from several factors, including the lack of CAD tools, small circuit density, small bandwidth and layout dependent noise figures. These factors are all related to each other, making the design of a high performance FPAA a multi-dimensional problem. A critical reason behind these difficulties is the non-ideal programming technology, which contributes a large portion of parasitics into the sensitive analog system. This paper presents a high performance, radiation hard Laser Field Programmable Analog Array (LFPAA) using LaserLink' s MakeLink TM technology. Because of its extremely low resistance, negligible parasitic capacitance and full compatibility with commercial CMOS process, MakeLink TM can fully reduce these FPAA design concerns and offer a breakthrough capability in analog array performance. The proposed LFPAA consists of a 4 x 4 array of Configurable Analog Blocks (CABs) surrounded by abundant interconnect resources. There are 16 PAD groups around the chip, and 8 tracks per X/Y channel. Each CAB has 4 input and 4 output pins with internal circuit operating in fully differential mode. With appropriate programming, the LFPAA can provide an accurate, low-cost and rapid-prototyping analog ASIC solution.
Accelerated Degradation Assessment of 18650 Lithium-Ion Batteries
Power fade of lithium cells due to accelerated factors of temperature and charging-discharging ra... more Power fade of lithium cells due to accelerated factors of temperature and charging-discharging rate was assessed. A lithium-ion battery aging model for predicting the power fade of 18650-size cells was applied, and then statistically accelerated degradation tests were performed to validate the model. The experimental results show that the higher temperature and charging-discharging rate lead more aging effects resulted in power degradation apparently. Validation of the empirical aging model by the experimental data depicts that the model is capable of predicting battery charging-discharging cycles at a specific condition with respect to temperature and charging-discharging rate combination if power degradation rate of the cell is defined.
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Papers by kuan-jung chung