Development and Experimental Validation of a 3-D Solder Self-Alignment Model for Alignment Accuracy Prediction of Flip-Chip Assembly

Kong, Ming; Jeon, Sungeun K.; Au, Hinmeng; Hwang, Chiwon; Lee, Yung-Cheng

doi:10.1109/tcpmt.2011.2162837

Cited by 8 publications

(11 citation statements)

References 16 publications

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“…6.1.2 Solders. Capillary self-alignment mediated by solder droplets in air was the first extensively studied self-alignment process, in the context of flip-chip [98][99][100][101] and surface-mount reflow soldering. 102,103 The self-centering force of the solder joint was clearly identified in early work 103 focusing on soldering defects.…”

Section: Process Integrationmentioning

confidence: 99%

Surface tension-driven self-alignment

et al. 2017

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Surface tension-driven self-alignment is a passive and highly-accurate positioning mechanism that can significantly simplify and enhance the construction of advanced microsystems. After years of research, demonstrations and developments, the surface engineering and manufacturing technology enabling capillary self-alignment has achieved a degree of maturity conducive to a successful transfer to industrial practice. In view of this transition, a broad and accessible review of the physics, material science and applications of capillary self-alignment is presented. Statics and dynamics of the self-aligning action of deformed liquid bridges are explained through simple models and experiments, and all fundamental aspects of surface patterning and conditioning, of choice, deposition and confinement of liquids, and of component feeding and interconnection to substrates are illustrated through relevant applications in micro- and nanotechnology. A final outline addresses remaining challenges and additional extensions envisioned to further spread the use and fully exploit the potential of the technique.

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Section: Process Integrationmentioning

confidence: 99%

Surface tension-driven self-alignment

et al. 2017

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“…It has been used by scientists to achieve micro-scale 3D structures (Gracias, Kavthekar, Love, Paul, & Whitesides, 2002;Harsh & Lee, 1998;Yang, Liu, Wang, & Tian, 2011;Yang, Wang, Liu, & Tian, 2012). SBSA is a simple and inexpensive method to create 3D structures (Rao, Lusth, & Burkett, 2009;Kong, Jeon, Au, Hwang, & Lee, 2011). Highly parallel fabrication of 3D structures is made possible by the SBSA approach (Rao, Lusth, & Burkett, 2012).…”

Section: Copyright By Author(s); Cc-by 13mentioning

confidence: 99%

A Solder Based Self Assembly Project In An Introductory IC Fabrication Course

Rao¹,

Lusth

Burkett

2015

AJEE

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Integrated circuit (IC) fabrication principles is an elective course in a senior undergraduate and early graduate student’s curriculum. Over the years, the semiconductor industry relies heavily on students with developed expertise in the area of fabrication techniques, learned in an IC fabrication theory and laboratory course. The theory course gives importance to the physics of manufacturing techniques and is often attached to a subsequent semester laboratory curriculum. The pre-requisite requirement of the theory component for a laboratory course requires students to enroll for two courses in separate semesters and is not an option for all students. Hence, an innovative student project is intended in the theory curriculum to give hands-on experience on the processes. The IC fabrication course is usually associated with high enrollment of students, leading to fewer laboratory experiments. The physics of IC fabrication techniques is important, but few students may perceive the theory as important with no laboratory experience. To improve the course and give students hands-on practice with existing state-of-the-art processing facilities, a tailored project was added to the syllabus. A solder-based self assembly (SBSA) project was introduced in the curriculum for the first time at the University of Alabama in Fall 2011. The student projects were designed in a way to provide an alternative to conventional time-intensive, high cost, and highly tool dependent IC fabrication lab experiments. SBSA forms three dimensional (3D) structures when applied to two dimensional (2D) patterns. The schedule was designed to accommodate theory classes aligned with the fabrication steps and completed by students. The project involved a brainstorming session, a design stage to develop 2D patterns using AutoCAD software, a deposition process, a lithography step, a dip soldering step, a reflow process, scanning electron microscope (SEM) imaging, and a final project presentation. Other processes required to complete the project were performed by the instructor. In general, students showed interest in working in teams, completing the project, and recommended to continuing the SBSA project in future IC fabrication course work. The SBSA project is cost effective and less tool dependent for incorporation in a semester long course. In addition, the project is time effective from both student and instructor perspectives.

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“…During the reflow process, the surface tension between the molten solder and mating Cu pads, causes the SMCs to move to the most stable position and automatically ensure the desired alignment [4], an effect is known as self-alignment. Self-alignment is one of the critical characteristics of a successful reflow process [5][6][7]. A comprehensive understanding of the characteristics of components self-alignment is vital to enhance SMCs' assembly quality.…”

Section: Introductionmentioning

confidence: 99%

The Dissimilar Self-Alignment Characteristics of Smaller Passive Components in the Length and Width Directions

Cen

et al. 2021

Journal of SMT

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Motivation: As passive components’ size gets smaller, quality rejects due to overhang and misalignment after the reflow appear more frequently. This situation is partly because the pass-fail criterion is set based on the offset concerning the component dimensions. Therefore, understanding the self-alignment characteristics of electronic components becomes very critical for surface-mount assembly yield. This research investigates the dissimilarity of self-alignment in the length and width directions. Approach: To avoid the argument of sample to sample variations, data are collected from 81 printed circuit boards (PCB) and 182,250 assembled components. Within a PCB, 25 different solder paste printing offset locations and 81 component placement offset settings are implemented. Component-placement positions before and after the reflow are monitored. The results are compared to identify different component sizes’ self-alignment characteristics in the length and width directions. Key findings: The misalignment of smaller passive components, e.g., R0402M(0.40 mm × 0.20 mm), is worse than the larger component under the identical solder paste printing and component placement conditions. Furthermore, the self-alignment characteristic in the length direction of these passive components, e.g., R0402M, to R1005M (1.00 mm × 0.50 mm) is superior to that of width direction. The observations are not consistent with the results found in earlier research that reported on larger components, e.g., C0402M(0.40 mm × 0.20 mm), to C3216M(3.20 mm × 1.50 mm).

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Development and Experimental Validation of a 3-D Solder Self-Alignment Model for Alignment Accuracy Prediction of Flip-Chip Assembly

Cited by 8 publications

References 16 publications

Surface tension-driven self-alignment

Surface tension-driven self-alignment

A Solder Based Self Assembly Project In An Introductory IC Fabrication Course

The Dissimilar Self-Alignment Characteristics of Smaller Passive Components in the Length and Width Directions

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