Low Temperature Wafer Bonding

Fournel, Frank; Moriceau, H.; Ventosa, C.; Libralesso, L.; Tiec, Y. Le; Signamarcheix, T.; Rieutord, F.

doi:10.1149/1.2982902

Cited by 19 publications

(10 citation statements)

References 28 publications

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“…The samples are expected to relax when their elastic energy, divided by the area in contact with the substrate, exceeds a certain threshold. From our set of samples, we estimate this elastic energy threshold to be at around 3 J/m² which is in the same order of magnitude compared to the bonding energies measured from wafer bonding experiments [28]- [30]. We hypothesize that further thermal annealing could increase this elastic energy threshold.…”

Section: Figure 2: (A) Design Parameter Used To Tune the Strain In Thsupporting

confidence: 57%

Highly strained Ge micro-blocks bonded on Si platform for mid-infrared photonic applications

et al. 2017

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Adding sufficient tensile strain to Ge can turn the material to a direct bandgap group IV semiconductor emitting in the mid-infrared wavelength range. However, highly strained-Ge cannot be directly grown on Si due to its large lattice mismatch. In this work, we have developed a process based on Ge micro-bridge strain redistribution intentionally landed to the Si substrate. Traction arms can be then partially etched to keep only localized strained-Ge micro-blocks. Large tunable uniaxial stresses up to 4.2% strain were demonstrated bonded on Si. Our approach allows to envision integrated strained-Ge on Si platform for mid-infrared integrated optics.Silicon photonics merges optical and electronic components to be integrated together onto a single microchip. Since the great interest in Si photonics has been demonstrated for telecommunication application more applications have emerged in the Mid-Infrared (MIR) wavelength range (2 to 5µm) like gas sensing [1]. Since the SiO 2 is transparent up to 3.5 µm wavelength [2], Silicon-On-Insulator (SOI) MIR spectrometers have been successfully demonstrated [3]. For longer wavelength, Ge on Si platform is instead used [4], [5]. However, the monolithically integration of active devices (sources and photodetector) are still missing to unlock all the possibilities for Si photonics in the MIR. The current solution consist of growing [6], [7] or bonding III-V materials [8], [9] on Si but these heterogeneous integration are not considered as Complementary Metal Oxide Semiconductor (CMOS) compatible by industrial foundries. For the group IV material sources, doped-Ge [10] and GeSn alloys [11] are envisioned to tackle the challenge to obtain a laser source CMOS compatible. Note that GeSn devices are also studied for photo-detection applications on Si substrate [12], [13]. Strained-Ge structures exhibits also a MIR direct bandgap [14], [15] but their integration, which require extra process step to localize and contact the strained-Ge, remains challenging. Such integration on a Si platform would open the way to MIR fully integrated active devices (source and detectors) which 2 are CMOS compatible. The availability of such approach would have many applications for sensing systems [2] or on-chip optical interconnects for high-performance computing [16].In this work, we propose to bond highly strained Ge directly on Si using a specific processing based on micro-bridge landing followed by the traction arm etching. Compared to free standing membranes, our landing approach will greatly facilitate the next process steps needed to go towards electrically pumped laser sources or integrated photodetectors based on strained-Ge for MIR applications. We measure a Raman spectral shift of around 8 cm -1 corresponding to 4.2% in a Ge micro-block directly bonded on Si which is higher than the first demonstration of 3 cm -1 using the biaxial approach [17]. Figure 1: Processing of a) Ge layer patterning; b) SiO 2 under-etching leading to concentrate the strain in the centre of landed micro-bridge; c) fina...

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Section: Figure 2: (A) Design Parameter Used To Tune the Strain In Thsupporting

confidence: 57%

Highly strained Ge micro-blocks bonded on Si platform for mid-infrared photonic applications

et al. 2017

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“…This hydrogen is trapped at the bonding interface, which generates bubbles. 10 One interesting application of the DEAE bonding energy enhancement at very low temperature is to reduce this well-known Si/Si hydrophilic bonding defectiveness. With scanning acoustic microscopy (SAM), we can see in Fig.…”

Section: Resultsmentioning

confidence: 99%

Impact of Amino-Alcohol Organic Molecule on Various Silicon Oxide Bondings

Calvez¹,

Fournel²,

Larrey³

et al. 2021

ECS J. Solid State Sci. Technol.

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Recently a new surface preparation method using an organic molecule was introduced for silicon direct wafer bonding F. Fournel, L. Continni, C. Morales, J. Da Fonseca, H. Moriceau, F. Rieutord, A. Barthelemy, and I. Radu, J. Appl. Phys., 111, 104907 (2012). Adding a very small amount of amino-alcohol molecule at the bonding interface drastically increased the bonding energy after low post bonding annealing temperature. In this study, additional developments using the same molecule type (DEAE: N-N-diethylaminoethanol) are presented.

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“…Direct bonding is used in this work to bond layer A1 with layer A2. It is known that the quality of Si-Si direct bonding is enhanced using a SiO 2 thin layer on the bonding interface (greater than 50 nm) [31]. The SiO 2 layer dissolves hydrogen generated at the annealing step avoiding voids and bubbles at the bond interface.…”

Section: Si-si Direct Bonding With Patterned Featuresmentioning

confidence: 99%

A MEMS Turbopump for High Temperature Rankine Micro Heat Engines—Part I: Design and Fabrication

Amnache

Liamini

Gauthier

et al. 2020

J. Microelectromech. Syst.

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We report the design and microfabrication of a MEMS turbopump with thermal insulation, as the core component of a steam power plant-on-a-chip for waste heat recovery based on the Rankine thermodynamic cycle. Based on a first-generation microturbopump for ambient temperature operation, this second-generation device introduces materials for thermal insulation and design improvements to the rotordynamic components for operation at high temperatures. Thermal management is required to prevent water boiling in the pump and vapor from condensing in the turbine, bearings and seals. The device is a five-wafer stack that encloses a 4-mm diameter rotor disk with microturbine blades on one side and a viscous micropump on the other. This second-generation microturbopump implements unique thermal insulation strategies to isolate the pump from the surrounding hot flows. An out-off-plane thick molded glass embedded into the rotor prevents heat conduction from the turbine to the pump. In addition, an in-plane thick array of oxidized trenches prevents heat conduction from the thrust bearing region to the pump. The assembled microturbopump is fabricated and tested, resulting in the first MEMS turbopump demonstrated at high temperature. Design and fabrication are covered herein, whereas experimental demonstration and characterization are presented in Part II of this two-part paper.

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Low Temperature Wafer Bonding

Cited by 19 publications

References 28 publications

Highly strained Ge micro-blocks bonded on Si platform for mid-infrared photonic applications

Highly strained Ge micro-blocks bonded on Si platform for mid-infrared photonic applications

Impact of Amino-Alcohol Organic Molecule on Various Silicon Oxide Bondings

A MEMS Turbopump for High Temperature Rankine Micro Heat Engines—Part I: Design and Fabrication

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