Hybrid bonding for 3D stacked image sensors: impact of pitch shrinkage on interconnect robustness

Jourdon, J.; Lhostis, S.; Moreau, S.; Chossat, J.; Arnoux, M.; Sart, Clement; Henrion, Y.; Lamontagne, P.; Arnaud, L.; Bresson, N.; Balan, V.; Euvrard, C.; Exbrayat, Y.; Scevola, Daniel; Deloffre, E.; Mermoz, S.; Martin, Andreas; Bilgen, H.; André, Franck; Charles, Christine; Bouchu, D.; Farcy, A.; Guillaumet, S.; Jouve, A.; Frémont, Hélène; Chéramy, S.

doi:10.1109/iedm.2018.8614570

Cited by 59 publications

(14 citation statements)

References 6 publications

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“…The cracking area in Figure 7 a is smaller than that in Figure 7 b, corresponding to a 4% difference in resistance change. It has been reported that the resistance increased by 5% as the contact ratio increased from 20% to 100% [ 44 ]. In this study, the resistance change is approximately 8–12% after 1000 cycles, and the crack distribution is very different ( Figure 7 a,b).…”

Section: Resultsmentioning

confidence: 99%

Failure Mechanisms of Cu–Cu Bumps under Thermal Cycling

Shie

Hsu

et al. 2021

Materials

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The failure mechanisms of Cu–Cu bumps under thermal cycling test (TCT) were investigated. The resistance change of Cu–Cu bumps in chip corners was less than 20% after 1000 thermal cycles. Many cracks were found at the center of the bonding interface, assumed to be a result of weak grain boundaries. Finite element analysis (FEA) was performed to simulate the stress distribution under thermal cycling. The results show that the maximum stress was located close to the Cu redistribution lines (RDLs). With the TiW adhesion layer between the Cu–Cu bumps and RDLs, the bonding strength was strong enough to sustain the thermal stress. Additionally, the middle of the Cu–Cu bumps was subjected to tension. Some triple junctions with zig-zag grain boundaries after TCT were observed. From the pre-existing tiny voids at the bonding interface, cracks might initiate and propagate along the weak bonding interface. In order to avoid such failures, a postannealing bonding process was adopted to completely eliminate the bonding interface of Cu–Cu bumps. This study delivers a deep understanding of the thermal cycling reliability of Cu–Cu hybrid joints.

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Section: Resultsmentioning

confidence: 99%

Failure Mechanisms of Cu–Cu Bumps under Thermal Cycling

Shie

Hsu

et al. 2021

Materials

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“…Recent pixel-level stacking technology [6], [37] and increase of integration capacity allow implementation of in-pixel comparator and in-pixel counter within practical pixel size, which suggests feasibility of the digital approach for nonlinear compression [50]. Advantages of photoresponse compression in digital domain are not only high stability toward various environment but also flexible programmability [95].…”

Section: A Nonlinear Response Hdrmentioning

confidence: 99%

“…Advancement of CMOS image sensor (CIS) technology and device integration, particularly backside illumination (BSI) technology and high-density wafer-to-wafer connection technology [4]- [6], allows implementation of a variety of HDR schemes within a practical pixel size. In this article, basic performance requirements to the automotive application are discussed in Section II, and the introduction of HDR technologies of CMOS image sensors and discussions for the automotive application will be given in Sections III and IV, respectively, and the conclusion will be given in Section V.…”

Section: Introductionmentioning

confidence: 99%

HDR CMOS Image Sensors for Automotive Applications

Takayanagi¹,

Kuroda

2022

IEEE Trans. Electron Devices

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Because of various purposes and high dynamic range (HDR) of brightness of objects in automotive applications, HDR image capture is a primary requirement. In this article, HDR CMOS image sensor (CIS) technology and its automotive applications are discussed including application requirements, basic HDR approaches and trends of HDR CMOS image sensor technologies, advantages and disadvantages for automotive application, and future prospect of the HDR technology. LED flicker caused by time aliasing effect and motion artifacts are two major issues in conventional multiple exposure HDR (MEHDR) approach, and several HDR technologies have been introduced for automotive applications. The advancements of image sensor fabrication technology, for instance, backside illumination (BSI) process and pixel level hybrid wafer bonding, have created new trends in the HDR technology.

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“…Cu/oxide hybrid bonding, on the other hand, with oxide or SiCN dielectrics has been adopted for fine-pitch packaging and can be scaled down continuously below the submicron scale [ 4 , 5 , 6 , 7 , 8 ]. Furthermore, copper shows low electrical resistivity (ρ) of 1.7 × 10 −6 Ω·cm 2 which is a constant that would be varied by different materials.…”

Section: Introductionmentioning

confidence: 99%

Low-Temperature Cu/SiO2 Hybrid Bonding with Low Contact Resistance Using (111)-Oriented Cu Surfaces

et al. 2022

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We adopted (111)-oriented Cu with high surface diffusivity to achieve low-temperature and low-pressure Cu/SiO2 hybrid bonding. Electroplating was employed to fabricate arrays of Cu vias with 78% (111) surface grains. The bonding temperature can be lowered to 200 °C, and the pressure is as low as 1.06 MPa. The bonding process can be accomplished by a 12-inch wafer-to-wafer scheme. The measured specific contact resistance is 1.2 × 10−9 Ω·cm2, which is the lowest value reported in related literature for Cu-Cu joints bonded below 300 °C. The joints possess excellent thermal stability up to 375 °C. The bonding mechanism is also presented to provide more understanding on hybrid bonding.

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Hybrid bonding for 3D stacked image sensors: impact of pitch shrinkage on interconnect robustness

Cited by 59 publications

References 6 publications

Failure Mechanisms of Cu–Cu Bumps under Thermal Cycling

Failure Mechanisms of Cu–Cu Bumps under Thermal Cycling

HDR CMOS Image Sensors for Automotive Applications

Low-Temperature Cu/SiO2 Hybrid Bonding with Low Contact Resistance Using (111)-Oriented Cu Surfaces

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