Collective laser‐assisted bonding process for 3D TSV integration with NCP

Braganca, Wagno Alves; Eom, Yong‐Sung; Jang, Keon‐Soo; Hwan, Moon; Bae, Hae-Young; Choi, Kwang-Seong

doi:10.4218/etrij.2018-0171

Cited by 18 publications

(5 citation statements)

References 14 publications

(18 reference statements)

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“…Through the optimization process, we finally applied a laser power of 160 W and laser irradiation time of 2 s. The size of the irradiated laser beam was equal to that of the substrate (225 mm 2 ); therefore, the laser power density was 0.71 W/mm 2 . We assumed that the silicon chip was 70 mm thick and had an absorption coefficient of 29.4% [ 24 ]. The area of the silicon chip was 49 mm 2 .…”

Section: Methodsmentioning

confidence: 99%

Mechanical Reliability Assessment of a Flexible Package Fabricated Using Laser-Assisted Bonding

Hwangbo

et al. 2023

Micromachines

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The aim of this study was to develop a flexible package technology using laser-assisted bonding (LAB) technology and an anisotropic solder paste (ASP) material ultimately to reduce the bonding temperature and enhance the flexibility and reliability of flexible devices. The heat transfer phenomena during the LAB process, mechanical deformation, and the flexibility of a flexible package were analyzed by experimental and numerical simulation methods. The flexible package was fabricated with a silicon chip and a polyimide (PI) substrate. When the laser beam was irradiated onto the flexible package, the temperatures of the solder increased very rapidly to 220 °C, high enough to melt the ASP solder, within 2.4 s. After the completion of irradiation, the temperature of the flexible package decreased quickly. It was found that the solder powder in ASP was completely melted and formed stable interconnections between the silicon chip and the copper pads, without thermal damage to the PI substrate. After the LAB process, the flexible package showed warpage of 80 μm, which was very small compared to the size of the flexible package. The stress of each component in the flexible package generated during the LAB process was also found to be very low. The flexible device was bent up to 7 mm without failure, and the flexibility can be improved further by reducing the thickness of the silicon chip. The bonding strength and environmental reliability tests also showed the excellent mechanical endurance of the flexible package.

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Section: Methodsmentioning

confidence: 99%

Mechanical Reliability Assessment of a Flexible Package Fabricated Using Laser-Assisted Bonding

Hwangbo

et al. 2023

Micromachines

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“…The contrast rate obtained on real PIC sample pictures confirm that the proposed IR microscope works for the test scenarios. The ability of vision through several layers of silicon is highly beneficial for 2.5D and 3D integration processes and bonding quality inspection [4], [28] - [29].…”

Section: Ir Microscope Optical Designmentioning

confidence: 99%

“…In case there are several peaks resulting from the analysis, the object of interest should be chosen manually. The ability of switching between several peaks for changing the best in-focus point between different layers of the stack is beneficial for 2.5D and 3D photonic integration processes and bonding quality inspection [4], [28] - [29]. This approach also could be used for estimating of the layer thickness in multi-layer silicon structure with resolution limited only by stage minimum travelling step.…”

Section: Tcpmt-2022-353mentioning

confidence: 99%

Machine Vision System Utilizing Black Silicon CMOS Camera for Through-Silicon Alignment

Власов

Aydin

Uusitalo

et al. 2022

IEEE Trans. Compon., Packag. Manufact. Technol.

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Current development trends concerning miniaturizing of electronics and photonics systems are aiming at assembly and 3D co-integration of a broad range of technologies including MEMS, microfluidics, wafer level optics, and silicon photonics. To this end, on-chip integration using silicon-photonics platform offers a wide range of possibilities addressing passive optics functionality, active optoelectronic devices, and compatibility with CMOS fabrication. On the other hand, the hybrid technology enabling volume manufacturing of such systemon-chip components it is still in an early development stage. Here, a new type of machine vision system enabling precision stacking and bonding processes of III-V components on silicon photonics chips is introduced. In particular, we focus on the ability to see through substrates with high resolution, which is crucial for the alignment of the markers used for assembly of integrated components on silicon wafer. The system is based on the use of a black silicon enhanced CMOS sensor with extended wavelength response beyond transparency cut off wavelength for silicon substrate. We study the use of the camera system as a microscope with bottom coaxial infrared illumination scheme and demonstrate the ability of through-silicon vision for one-and twolayered silicon photonic integrated circuit samples. The ability of observing objects with dimensions down to 2 µm is confirmed. This resolution is close to diffraction limit and corresponds to the dimensions of optical waveguide structures on the photonic integrated circuits surface. In addition, we demonstrate the implementation of a two-dimensional Fourier transform based autofocusing technique for through-silicon IR microscopy. These building blocks offer a solution for advanced photonic integration processes and other through-silicon vision related applications, which is instrumental for a large variety of assembly, lithography, and wafer bonding setups.

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“…LAB is a semiconductor packaging process in which a laser beam is selectively applied to a target flip-chip die and/or surface-mount component for less than a couple of seconds. [15][16][17][18][19][20] The interaction between the laser beam and the target device increases its temperature, thus allowing it to be metallurgically bonded to a substrate, interposer, or another die. The LAB system (Fig.…”

Section: Laser-assisted Bondingmentioning

confidence: 99%

Characterization of laser beams: theory and application in laser-assisted bonding process

Braganca

Kim

2021

Opt. Eng.

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The International Organization for Standardization (ISO), in collaboration with the academic community, has developed and published a comprehensive system of standards for the characterization of optical components and laser beams. Our study offers a pedagogical introduction to the theory and application of laser beam characterization in accordance with ISO 13694:2018 and ISO 11145:2018. The characterizing parameters of each ISO standard are presented, defined mathematically, and explained in detail through the use of a minimum working example. A laser beam applied to an actual industrial process [laser-assisted bonding (LAB) process in the semiconductor packaging industry] is thoroughly analyzed to help the reader understand and interpret the characterizing results. Background noise correction and unit conversion methods are also discussed. We target researchers new to the field of laser beam analysis who want the acquire background knowledge, as well as more experienced researchers who want to implement their own laser beam analysis software and propose new definitions for their specific application. Although our study deals with only two ISO standards, the methods covered in our study can be easily applied to other norms that fit the reader's application. Our study should not be treated as a full review of the LAB process nor of the beam profiling instruments and measurement principles. These are only mentioned to enhance the reader's learning experience.

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Collective laser‐assisted bonding process for 3D TSV integration with NCP

Cited by 18 publications

References 14 publications

Mechanical Reliability Assessment of a Flexible Package Fabricated Using Laser-Assisted Bonding

Mechanical Reliability Assessment of a Flexible Package Fabricated Using Laser-Assisted Bonding

Machine Vision System Utilizing Black Silicon CMOS Camera for Through-Silicon Alignment

Characterization of laser beams: theory and application in laser-assisted bonding process

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