Effect of Wafer Level Underfill on the Microbump Reliability of Ultrathin-Chip Stacking Type 3D-IC Assembly during Thermal Cycling Tests

Lee, Chang‐Chun

doi:10.3390/ma10101220

Cited by 9 publications

(3 citation statements)

References 22 publications

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“…Recently, electronic encapsulation and the development of underfill materials have attracted considerable interest in heat dissipation and have become the most cutting-edge approaches in this field. An ideal underfill material must not only have high thermal conductivity (TC) but also low coefficient of thermal expansion (CTE), as underfilling shields the die bumps from thermomechanical stress generated between the die and substrate or another die, thus improving the link strength of electrical junctions and compensating for the differences in thermal expansion between two connecting materials, which might lead to device malfunction [ 10 , 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

Highly Thermally Conductive Epoxy Composites with AlN/BN Hybrid Filler as Underfill Encapsulation Material for Electronic Packaging

Sanchez

Chiu

et al. 2022

Polymers

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In this study, the effects of a hybrid filler composed of zero-dimensional spherical AlN particles and two-dimensional BN flakes on the thermal conductivity of epoxy resin were studied. The thermal conductivity (TC) of the pristine epoxy matrix (EP) was 0.22 W/(m K), while the composite showed the TC of 10.18 W/(m K) at the 75 wt% AlN–BN hybrid filler loading, which is approximately a 46-fold increase. Moreover, various essential application properties were examined, such as the viscosity, cooling rate, coefficient of thermal expansion (CTE), morphology, and electrical properties. In particular, the AlN–BN/EP composite showed higher thermal stability and lower CTE (22.56 ppm/°C) than pure epoxy. Overall, the demonstrated outstanding thermal performance is appropriate for the production of electronic packaging materials, including next-generation flip-chip underfills.

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Section: Introductionmentioning

confidence: 99%

Highly Thermally Conductive Epoxy Composites with AlN/BN Hybrid Filler as Underfill Encapsulation Material for Electronic Packaging

Sanchez

Chiu

et al. 2022

Polymers

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“…Out of the demand to realize more wafers stacking layer-by-layer, wafer needs to be thinned from about 780 µm to less than 10 µm and be processed to the status with a demanding thickness uniformity [3]. For a better chip thermo-mechanical reliability, the wafer needs to be processed to a proper thickness [4]. Except the high surface accuracy and integrity [5][6][7], the process efficiency and thickness uniformity are the main requirements for wafer thinning technology.…”

Section: Introductionmentioning

confidence: 99%

An Investigation on the Total Thickness Variation Control and Optimization in the Wafer Backside Grinding Process

et al. 2022

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The wafer backside grinding process has been a crucial technology to realize multi-layer stacking and chip performance improvement in the three dimension integrated circuits (3D IC) manufacturing. The total thickness variation (TTV) control is the bottleneck in the advanced process. However, the quantitative analysis theory model and adjustment strategy for TTV control are not currently available. This paper developed a comprehensive simulation model based on the optimized grinding tool configuration, and several typical TTV shapes were obtained. The relationship between the TTV feature components and the spindle posture was established. The linear superposition effect of TTV feature components and a new formation mechanism of TTV shape were revealed. It illustrated that the couple variation between the two TTV feature components could not be eliminated completely. To achieve the desired wafer thickness uniformity through a concise spindle posture adjustment operation, an effective strategy for TTV control was proposed. The experiments on TTV optimization were carried out, through which the developed model and TTV control strategy were verified to play a significant role in wafer thickness uniformity improvement. This work revealed a new insight into the fine control method to the TTV optimization, and provided a guidance for high-end grinding tool and advanced thinning process development.

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“…There are 11 kinds of TC test condition [153], and they are listed in Table 2 internal force within a package. The internal force could provide the tension force or compression force to accelerate the package structure deformation [155][156][157][158][159]. The TC test temperature changes rapidly and the temperature range is large.…”

Section: Temperature Cycling Testmentioning

confidence: 99%

Advanced flip chip and wafer level packages for 2.5D and 3D IC package technology

Xu¹

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The demand of electronic product explodes in recent years, and the trend of electronic product is portable, multifunctional and budget currently. The fan-out wafer level packaging technology is a kind of wafer level packaging technology, and it becomes more and more attractive and popular because of its flexibility to integrate diverse devices in a very small form factor. The fan-out wafer level packaging technology has the advantages of high density of input/output, minimal package size and low cost. The fan-out wafer level package (FOWLP) is usually used to volume sensitive devices such as mobile phones and wearables. However, the strength of ultrathin FOWLP is low, and the low package strength often leads to crack issues. Therefore, the study of strength behavior of FOWLP is essential. FOWLP is made up of various materials and thus the proper structure design and material selection are important to meet the reliability requirement. The FOWLP strength is evaluated by the experimental method and numerical method. We confirm three significant characteristics of FOWLP strength from the experimental work. The wafer grinding process, FOWLP dimension and thermal factor affect the FOWLP strength significantly. The numerical work proves that the flexure strength of over-molded structure FOWLP is higher than the flexure strength of other structure FOWLPs with the same package thickness. Two theoretical models of FOWLP strength are proposed. These two models are based on the location of FOWLP initial fracture point. The comparison of FOWLP strength model with experiment results and simulation results shows that they are identical. A new theoretical model of FOWLP fatigue crack growth is proposed. This model additionally considers the effect of thermal factor on the FOWLP fatigue crack growth. ii ACKNOWLEDGMENT The author would like to express his gratitude to the people who have given their hands throughout the author's Ph.D. study journey. The author's thanks and appreciations also extend to: Associate Professor Zhong Zhaowei, the author's supervisor. He shows his generosity, encouragement and patience in guiding the author in various aspects during the Ph.D. study. He is also always trying to motivate and encourage the author to reach his goal. Dr. Choi Won Kyoung, the author's co-supervisor. She shows her attention, suggestion and guidance to the author. She also shares a lot of her knowledge and experience on the aspect of advanced packaging with the author. She is also always explaining the author's doubts throughout the project. Ms. Heng Chee Hoon, NTU biological laboratory assistant manager, Mr. Leong Kwok Phui, NTU materials laboratory manager and Ms. Yeong Peng Neo, NTU materials laboratory Executive. They show their generosity and patience in guiding and teaching the author to use the laboratory machines. They also provide the technical support to the author's experiment from hardware to software. Ms. Lee Koon Fong, mechatronics laboratory manager. She kindly and tremendously helps the author to purchase necess...

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Effect of Wafer Level Underfill on the Microbump Reliability of Ultrathin-Chip Stacking Type 3D-IC Assembly during Thermal Cycling Tests

Cited by 9 publications

References 22 publications

Highly Thermally Conductive Epoxy Composites with AlN/BN Hybrid Filler as Underfill Encapsulation Material for Electronic Packaging

Highly Thermally Conductive Epoxy Composites with AlN/BN Hybrid Filler as Underfill Encapsulation Material for Electronic Packaging

An Investigation on the Total Thickness Variation Control and Optimization in the Wafer Backside Grinding Process

Advanced flip chip and wafer level packages for 2.5D and 3D IC package technology

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