scholarly journals A Robust Approach of Maintaining Epoxy Position on Die Attach Process of Tapeless QFN Packages

2021 ◽  
pp. 109-114
Author(s):  
Jerome J. Dinglasan ◽  
Leandro D. Saria ◽  
Frederick Ray I. Gomez
Keyword(s):  
Design Optimization ◽  
Process Improvement ◽  
Innovative Approach ◽  
Great Role ◽  
Robust Approach ◽  
Die Attach ◽  
Current Design ◽  
Position Shift ◽  
Improved Design ◽  
Set Up

Epoxy quality contributes a great role in defining quality products of quad flat no lead multi row packages. In dealing with certain problems related to epoxy position shift caused by unoptimized design, innovation on the dispenser module is considered and focused at. This paper discusses the phenomenal issue of epoxy position shifting in die attach process and the solutions applied. The current design of dispenser module in die attach machine demonstrates flaws that need to be improved through design optimization. Innovative approach was applied, removing variables on the design that caused rejections during die attachment due to the shifted epoxy position. The improved design was able to address the issue as projected on the study, and helps not only the epoxy position performance, but also the set-up time of epoxy during syringe replacement. This design can be adapted by other manufacturing for process improvement and robustness.

Experimental Investigation into Driver Behavior along Curved and Parallel Diverging Terminals of Exit Interchange Ramps

2021 ◽  
pp. 036119812199742
Author(s):  
Alberto Portera ◽  
Marco Bassani
Keyword(s):  
Design Stage ◽  
Lane Change ◽  
Age And Gender ◽  
Traffic Conditions ◽  
Current Design ◽  
The Difference ◽  
Safety Countermeasures ◽  
And Gender ◽  
Set Up ◽  
Curve Radius

Current design manuals provide guidance on how to design exit ramps to facilitate driving operations and minimize the incidence of crashes. They also suggest that interchanges should be built along straight roadway sections. These criteria may prove ineffective in situations where there is no alternative to terminals being located along curved motorway segments. The paper investigates driving behavior along parallel deceleration curved terminals, with attention paid to the difference in impact between terminals having a curvature which is the same sign as the motorway segment (i.e., continue design), and those having an opposite curvature (i.e., reverse design). A driving simulation study was set up to collect longitudinal and transversal driver behavioral data in response to experimental factor variations. Forty-eight drivers were stratified on the basis of age and gender, and asked to drive along three randomly assigned circuits with off-ramps obtained by combining experimental factors such as motorway mainline curve radius (2 values), terminal length (3), curve direction (2), and traffic conditions (2). The motorway radius was found to be significant for drivers’ preferred speed when approaching the terminal. Terminal length and traffic volume do not have a significant impact on either longitudinal or transversal driver outputs. However, the effect of curve direction was found to be significant, notably for reverse terminals which do not compel drivers to select appropriate speeds and lane change positions. This terminal type can give rise to critical driving situations that should be considered at the design stage to facilitate the adoption of appropriate safety countermeasures.

scholarly journals Glue Voids Reduction on QFN Device through Material and Process Improvement

2021 ◽  
pp. 15-19
Author(s):  
Edwin M. Graycochea Jr. ◽  
Endalicio D. Manalo ◽  
Rennier S. Rodriguez ◽  
Frederick Ray I. Gomez
Keyword(s):  
Process Optimization ◽  
Process Improvement ◽  
Machine Process ◽  
Stencil Printing ◽  
Main Contributor ◽  
Die Attach ◽  
Material Preparation

The paper is focused on the glue voids reduction on critical semiconductor quad-flat no-leads (QFN) device processed on a stencil printing type of die attach machine. Process optimization through material preparation improvement was done to mitigate the silver lumps of the sintering glue which is a main contributor on the voids occurrence. Eventually, the glue voids were reduced to less than the allowed 5% limit. For future works, the learnings and configuration could be used on devices with similar requirement.

Improved Design of Vertical Curves with Sight Distance Profiles

2003 ◽  
Vol 1851 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Yasser Hassan
Keyword(s):  
Design Procedure ◽  
The United States ◽  
Analytical Models ◽  
Minimum Length ◽  
Vertical Alignment ◽  
The Road ◽  
Sight Distance ◽  
Special Cases ◽  
Current Design ◽  
Improved Design

Design of vertical alignment is one of the main tasks in highway geometric design. This task requires, among other things, that the designer ensure drivers always have a clear view of the road so they can stop before hitting an unexpected object in the road. Therefore, the ability to determine the required and available stopping sight distance (SSD) at any point of the vertical alignment is essential for the design process. Current design guides in the United States and Canada provide simple analytical models for determining the minimum length of a vertical curve that would satisfy the sight distance requirement. However, these models ignore the effect of grade on the required SSD. Alternative approaches and models have also been suggested but cover only special cases of vertical curves. Two specific models were expanded to determine the required SSD on crest and sag vertical curves. By comparing profiles of available SSD and required SSD on examples of vertical curves, it was shown that current North American design practices might yield segments of the vertical curve where the driver’s view is constrained to a distance shorter than the required SSD. An alternative design procedure based on the models was developed and used to determine the minimum lengths of crest and sag vertical curves. Depending on the approach grade, these new values of minimum curve length might be greater than or less than values obtained through conventional design procedures. Design aids were therefore provided in tabular form for designers’ easy and quick use.

scholarly journals Improved Tank Car Safety Research

2007 ◽  
Author(s):  
David Tyrell ◽  
David Jeong ◽  
Karina Jacobsen ◽  
Eloy Martinez
Keyword(s):  
Structural Integrity ◽  
Hazardous Material ◽  
Research Results ◽  
Chemical Company ◽  
Safety Research ◽  
Current Design ◽  
Improved Design ◽  
Accident Scenarios ◽  
Company Union ◽  
The Impact

Three recent accidents involving the release of hazardous material have focused attention on the structural integrity of railroad tank cars: (1) Minot, ND, on January 18, 2002; (2) Macdona, TX, on June 28, 2004; and (3) Graniteville, SC, on January 6, 2005. Each of these accidents resulted in fatalities. Research is being conducted to develop strategies for improving railroad tank cars so they can maintain tank integrity in severe accidents. A collaborative effort called the Next Generation Rail Tank Car (NGRTC) Project intends to use these research results to help develop improved tank car designs. Dow Chemical Company, Union Pacific Railroad, and Union Tank Car Company are the industry sponsors of the NGRTC Project. The Federal Railroad Administration (FRA) and Transport Canada participate in the NGRTC project through Memoranda of Cooperation. FRA and the Pipeline and Hazardous Materials Safety Administration intend to use these research results to support rulemaking. The approach taken in performing this research is to define the collision conditions of concern, to evaluate the behavior of current design equipment in these scenarios, and to develop alternative strategies for increasing the maximum impact speed for which tank integrity is maintained. The accident scenarios have been developed from a review of accidents and are intended to bound the range of main-line accidents that can lead to a release of hazardous material from a tank car. The accident scenarios and collision modes have been used to define car-to-car impact scenarios. These car-to-car impact scenarios define the conditions under which the commodity must be contained. The impact scenarios are being used to evaluate the integrity of current design and improved design tank cars. Full-scale impact tests are also being conducted, to help validate modeling of the baseline equipment. The models have been refined based on the test results. The models are now being applied to develop the improved equipment designs. This paper describes the overall research framework and provides an overview of the research done to date, as well as the planned efforts.

Die Attach Process Analysis of Enhanced Stand-off Stopper on Tapeless Leadframe

2020 ◽  
pp. 22-26
Author(s):  
E. Graycochea Jr. ◽  
F. Gomez ◽  
R. Rodriguez ◽  
B. Bacquian
Keyword(s):  
Process Analysis ◽  
Semiconductor Industry ◽  
Bond Line ◽  
Line Thickness ◽  
Design Structure ◽  
Die Attach ◽  
Bond Line Thickness ◽  
Improved Design

Improvement on the process and design is often a reliable way to resolve a problem especially in semiconductor industry. This paper presents a leadframe or semiconductor carrier merged with a stand-off design structure that will maintain a consistent bond line thickness (BLT) criteria for quad-flat no-leads (QFN) packages. Through package and process conceptualization, the stand-off design located on the leadframe underneath the silicon die corners would result to a steady and consistent BLT during die attach process. With the improved design, die tilt occurrence in die attach process would be mitigated.

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