Novel method for crystal defect analysis of laser drilled TSVs

Rieske, Ralf; Landgraf, R.; Wolter, Klaus‐Jürgen

doi:10.1109/ectc.2009.5074155

Cited by 10 publications

(8 citation statements)

References 7 publications

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“…But the function ݂൫ ೌ ೃ ൯ is of maximum value of 0.24 at ܽ/ܴ = 0.5, as shown in Figure 2. So in design, the worst case scenario can be implemented as: Laser drilling is one popular method to form through hole in silicon due to its low cost, time efficiency and layout flexibility, but induced a damaged zone in silicon around the hole with large cracks [24]. The typical crack size could vary from several microns to tens of microns, comparable with the via size [25,26].…”

Section: Model and Formulationmentioning

confidence: 99%

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Guideline to avoid cracking in 3D TSV design

Zhang

2010

2010 12th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems

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Three dimensional through-silicon via (3D TSV) technology emerges due to the requirement of high performance, low cost and small form factor in the three dimensional packaging technology. The typical TSV structure is a thin silicon wafer drilled with through hole, the inside wall of the hole is plated with dielectric SiO 2 and diffusion barrier such as Ta, and then the hole is filled by Cu or W as the conductor. During fabrication, testing and service, the packages with TSV structures usually undergo temperature excursion. When the operation temperature is higher than stress-free temperature, the expansion of metal via will induces tensile stresses in circumferential direction in silicon interposer due to the mismatch of coefficient of thermal expansion. The tensile stress could drive the microcracks within the SiO 2 and silicon to initiate and finally break the silicon interposer by radial cracking. In the current paper, a design guideline is established based on fracture mechanics to avoid such failure, including the parameters such as via radius, flaw size, Young's modulus, coefficient of thermal expansion, and fracture toughness. The explicit expression in mathematical form makes such a guideline easily implemented in 3D TSV design.

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Section: Model and Formulationmentioning

confidence: 99%

“…The tensile hoop stress can drive the microcracks within the SiO 2 and/or silicon to initiate and finally break the silicon interposer by radial cracking [24][25][26]. This paper formulates an analytical method to analyze this phenomenon and establish a design guideline to avert radial cracking.…”

Section: Introductionmentioning

confidence: 98%

Guideline to avoid cracking in 3D TSV design

Zhang

2010

2010 12th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems

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“…However, the maximum number of parallel beams is limited by the power of the laser and the minimum energy [45] (Reprint with permission), (b) Appearance after wet etching/polishing [45] (Reprint with permission), (c) Dependence of etching rates on via diameters and depths [47] (XsiL, reprint with permission from IMAPS). [41] density required for ablation, while the pitch and density of the TSV array are limited by the size of the microlens. The drilling mechanism of femto-second lasers differs from that of nano-second lasers due to the significant difference in pulse duration, as illustrated in Table 1 [41].…”

Section: A Via Formationmentioning

confidence: 99%

“…[41] density required for ablation, while the pitch and density of the TSV array are limited by the size of the microlens. The drilling mechanism of femto-second lasers differs from that of nano-second lasers due to the significant difference in pulse duration, as illustrated in Table 1 [41]. For nano-second lasers, the duration of each laser pulse is between 10 −12 and 10 −9 s, much longer than the phonon-to-electron conversion time of most materials (about 10 −12 s).…”

Section: A Via Formationmentioning

confidence: 99%

3-D Integration and Through-Silicon Vias in MEMS and Microsensors

Wang

2015

J. Microelectromech. Syst.

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After two decades of intensive development, 3-D integration has proven invaluable for allowing integrated circuits to adhere to Moore's Law without needing to continuously shrink feature sizes. The 3-D integration is also an enabling technology for hetero-integration of microelectromechanical systems (MEMS)/microsensors with different technologies, such as CMOS and optoelectronics. This 3-D heterointegration allows for the development of highly integrated multifunctional microsystems with small footprints, low cost, and high performance demanded by emerging applications. This paper reviews the following aspects of the MEMS/ microsensor-centered 3-D integration: fabrication technologies and processes, processing considerations and strategies for 3-D integration, integrated device configurations and wafer-level packaging, and applications and commercial MEMS/ microsensor products using 3-D integration technologies. Of particular interest throughout this paper is the heterointegration of the MEMS and CMOS technologies. [2015-0158]Index Terms-Three-dimensional (3-D) integration, microelectromechanical systems (MEMS), microsensor, packaging, hetero-integration, interposer, through-silicon-via (TSV), waferlevel packaging, microsystem.

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“…By using these lasers, the heataffected zone inevitably created during laser ablation can be reduced [19,20]. In TSV technology, it is crucial to minimize the heat-affected zone around the holes since the small cracks generated from this zone become larger, eventually damaging the circuit board [21]. However, although ultra-short pulse lasers can reduce the heat-affected zone, all holes observed thus far have still exhibited heat-affected zones.…”

Section: Introductionmentioning

confidence: 99%

Comparison of bending fracture strength of silicon after ablation with nanosecond and picosecond lasers

Noh

Kim

Sohn

et al. 2015

Int J Adv Manuf Technol

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The demands of drilling on silicon wafers in multichip packages (MCPs) that employ laser ablation have increased. In this study, the bending fracture strengths of silicon specimens were experimentally measured using a four-point bending test after ablation with nanosecond and picosecond lasers. The specimens drilled with the picosecond laser showed a mean bending fracture strength (1530 MPa) higher than that of the specimens drilled with the nanosecond laser (678 MPa). One reason for this difference is that the crosssectional roughnesses of the specimens drilled with the picosecond laser were less than those of the samples drilled with the nanosecond laser. Consequently, for the purpose of MCP interconnections, silicon wafer drilling with a picosecond laser is preferable to drilling with a nanosecond laser since the former yields greater bending fracture strength.

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Novel method for crystal defect analysis of laser drilled TSVs

Cited by 10 publications

References 7 publications

Guideline to avoid cracking in 3D TSV design

Guideline to avoid cracking in 3D TSV design

3-D Integration and Through-Silicon Vias in MEMS and Microsensors

Comparison of bending fracture strength of silicon after ablation with nanosecond and picosecond lasers

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