Mechanical Reliability Analysis of Ultra-Thin Chip-on-Foil Assemblies under Different Types of Recurrent Bending

Palavesam, Nagarajan; Bonfert, Detlef; Hell, Waltraud; Landesberger, Christof; Gieser, H.; Kutter, Christoph; Bock, Karlheinz

doi:10.1109/ectc.2016.154

Cited by 12 publications

(4 citation statements)

References 8 publications

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“…The PCBs were in turn connected to a parameter analyser (HP 4156C) that offered high precision resistance measurements down to micro Ohms. Comprehensive explanation about the test equipment and the test protocol have been elaborated in our earlier papers [48,51]. The cyclic procedure followed for the bending test consists of four sequential steps as mentioned below.…”

Section: Fatigue Reliability Of R2r Microfabricated Wiring Linesmentioning

confidence: 99%

Roll-to-roll processing of film substrates for hybrid integrated flexible electronics

Palavesam

Marı́n

Hemmetzberger

et al. 2018

Flex. Print. Electron.

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Roll-to-roll (R2R) processing on film substrates has been demonstrated to have the potential for achieving high throughput manufacturing of organic electronic systems at low cost. However, the ever-growing mobile devices market accompanied by the developments in information and communication technologies require high performance systems at very low power operation, sometimes on larger substrates having sizes in the range of a few metres. Organic electronics often fall short of fulfilling the required computing performance and power requirements of most of the common use cases. Hybrid integration of inorganic monocrystalline silicon chips on polymer films is a means to fulfil the aforementioned requirements. In this context, it is opportune to report our recent activities on R2R processing of plastic films for hybrid integration of flexible electronics. Hybrid integration can be performed with conventional, rigid surface mount devices as well as flexible, ultrathin bare silicon chips. The first section of the paper is dedicated to a brief overview of R2R manufacturing of electronic devices with an example of production of radio frequency identification tags as well as to a discussion emphasising the targets for hybrid integration. Then, detailed descriptions about our processes for R2R manufacturing of metal wiring lines on films and hybrid integration are included. Three-dimensional integration of films and a temperature sensor label manufactured using hybrid integration process are also elaborated on. Furthermore, key results from fatigue reliability assessment of R2R metallised wiring lines are reported. Finally, some of the challenges in transferring the R2R processes for hybrid integration on film substrates from research labs to industrial manufacturing are highlighted.

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Section: Fatigue Reliability Of R2r Microfabricated Wiring Linesmentioning

confidence: 99%

Roll-to-roll processing of film substrates for hybrid integrated flexible electronics

Palavesam

Marı́n

Hemmetzberger

et al. 2018

Flex. Print. Electron.

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“…[ 31 ] More advanced test setups and protocols were developed to evaluate the reliability of complex hybrid integration of chip‐on‐flex, flex‐to‐flex assemblies, and roll‐to‐roll (R2R) printed circuits. [ 32–34 ]…”

Section: Introductionmentioning

confidence: 99%

“…[31] More advanced test setups and protocols were developed to evaluate the reliability of complex hybrid integration of chip-on-flex, flexto-flex assemblies, and roll-to-roll (R2R) printed circuits. [32][33][34] This work presents a comprehensive study on the reliability of hybrid integration of thinned bare die chip on soft and stretchable substrate. More specifically, the findings of this study are expected to provide fundamental insights on the failure mechanisms, their corresponding contributors, and ways to minimize them.…”

mentioning

confidence: 99%

Failure Mechanisms in Flip‐Chip Bonding on Stretchable Printed Electronics

et al. 2021

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Growing advances in printed flexible electronics enable novel design and manufacturing processes of electrical circuits and components in aircraft and automotive industries, [1][2][3] as well as in consumer electronics for fabrication of printed passive components, semiconductor devices, and sensing elements. [4][5][6][7][8][9][10][11][12][13][14][15] In the healthcare domain, the impact of printed electronics becomes more profound and offers a wide range of applications from printed RF coils for medical imaging, [16] biochemical sensing, [17,18] vital sign monitoring [19][20][21][22][23][24][25] to assistive wearable devices. [26,27] At the industrial level, its low cost and high-throughput manufacturing process are the key motivators for transition from conventional solutions to printed technologies. In wearable applications, its capability to realize soft wearable sensors, which can comply with the dynamic deformations of human skin, is attractive.Despite the promising opportunities of printed electronics in different domains, there are concerns regarding the reliability of printed materials (i.e., conductive inks, isolators, and adhesives) and their interconnections to electronic components for longterm use in real-life applications. Over the past decade, there has been an increasing number of studies on the reliability of printed conductors, interconnections, and chip-on-flex assembly. As a fundamental test, the cyclic bending endurance of printed conductors was investigated to analyze the characteristics of conductive tracks on a flexible substrate. [28][29][30] In more complicated test protocols, the influence of environmental parameters (e.g., temperature, humidity, etc.) was included in the test procedure. [31] More advanced test setups and protocols were developed to evaluate the reliability of complex hybrid integration of chip-on-flex, flexto-flex assemblies, and roll-to-roll (R2R) printed circuits. [32][33][34] This work presents a comprehensive study on the reliability of hybrid integration of thinned bare die chip on soft and stretchable substrate. More specifically, the findings of this study are expected to provide fundamental insights on the failure mechanisms, their corresponding contributors, and ways to minimize them. This study is divided into three phases as shown in Figure 1A. In the screening phase, the electromechanical performance of five different ink variants is evaluated and the most suitable ink variants are selected to be used in combination with three different types of conductive adhesive for fabrication and assembly of the test device. In the last phase of the study, the fabricated test devices are tested through a cyclic strain test and a comprehensive analysis of failure mechanisms is performed. The importance of the failure analysis is recognized in refining of the design steps, material selection, and processing parameters for improved reliability.

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“…A majority of the aforementioned applications require devices that are anticipated to bend repeatedly during the device usage, for, e.g., sensors and actuators placed in smart plasters and electronic skin. However, FHE is a relatively younger field of research that is still in its nascent stages of development and hence, information available regarding the static [27][28][29][30][31][32] as well as dynamic bending reliability [33][34][35][36] of FHE components is rather very limited. Several studies have shown that the failure of chip-foil packages during repeated bending occur mainly because of the cracking of interconnects rather than the delamination of the chip from foil or chip fracture [34][35][36].…”

Section: Introductionmentioning

confidence: 99%

Influence of Flexibility of the Interconnects on the Dynamic Bending Reliability of Flexible Hybrid Electronics

et al. 2020

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The growing interest towards thinner and conformable electronic systems has attracted significant attention towards flexible hybrid electronics (FHE). Thin chip-foil packages fabricated by integrating ultra-thin monocrystalline silicon integrated circuits (ICs) on/in flexible foils have the potential to deliver high performance electrical functionalities at very low power requirements while being mechanically flexible. However, only very limited information is available regarding the fatigue or dynamic bending reliability of such chip-foil packages. This paper reports a series of experiments where the influence of the type of metal constituting the interconnects on the foil substrates on their dynamic bending reliability has been analyzed. The test results show that chip-foil packages with interconnects fabricated from a highly flexible metal like gold endure the repeated bending tests better than chip-foil packages with stiffer interconnects fabricated from copper or aluminum. We conclude that further analysis work in this field will lead to new technical concepts and designs for reliable foil based electronics.

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Mechanical Reliability Analysis of Ultra-Thin Chip-on-Foil Assemblies under Different Types of Recurrent Bending

Cited by 12 publications

References 8 publications

Roll-to-roll processing of film substrates for hybrid integrated flexible electronics

Roll-to-roll processing of film substrates for hybrid integrated flexible electronics

Failure Mechanisms in Flip‐Chip Bonding on Stretchable Printed Electronics

Influence of Flexibility of the Interconnects on the Dynamic Bending Reliability of Flexible Hybrid Electronics

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