Mechanical Characterization and Micro Structure Diagnostics of Glass Frit Bonded Interfaces

Boettge, Bianca; Dresbach, Christian; Graff, Andreas; Petzold, Matthias; Bagdahn, J.

doi:10.1149/1.2982898

Cited by 11 publications

(4 citation statements)

References 2 publications

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“…In the absence of the knowledge about the effective bonding geometry (i.e., as obtained from process), wrong conclusions would be inferred from the tests. For [ 17 ], lead precipitates in the gf layer can reduce the strength at the gf-Si interconnection during tensile tests, while their influence appeared lower in micro-chevron tests. Ref.…”

Section: Introductionmentioning

confidence: 99%

An Experimental and Numerical Study on Glass Frit Wafer-to-Wafer Bonding

et al. 2023

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A thermo-mechanical wafer-to-wafer bonding process is studied through experiments on the glass frit material and thermo-mechanical numerical simulations to evaluate the effect of the residual stresses on the wafer warpage. To experimentally characterize the material, confocal laser profilometry and scanning electron microscopy for surface observation, energy dispersive X-ray spectroscopy for microstructural investigation, and nanoindentation and die shear tests for the evaluation of mechanical properties are used. An average effective Young’s modulus of 86.5 ± 9.5 GPa, a Poisson’s ratio of 0.19 ± 0.02, and a hardness of 5.26 ± 0.8 GPa were measured through nanoindentation for the glass frit material. The lowest nominal shear strength ranged 1.13 ÷ 1.58 MPa in the strain rate interval to 0.33 ÷ 4.99 × 10−3 s−1. To validate the thermo-mechanical model, numerical results are compared with experimental measurements of the out-of-plane displacements at the wafer surface (i.e., warpage), showing acceptable agreement.

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Section: Introductionmentioning

confidence: 99%

An Experimental and Numerical Study on Glass Frit Wafer-to-Wafer Bonding

et al. 2023

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“…On the contrary, glass frit bonds also had shortcomings in terms of the wide bonding rim (>200 µm) and the possible introduction of contaminations (Pb, Bi, etc.) to the components [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Glass Frit Jetting for Advanced Wafer-Level Hermetic Packaging

2022

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Glass frit bonding is a widely used technology to cap and seal micro-electromechanical systems on the wafer level using a low melting point glass. Screen printing is the main method to apply glass frit paste on wafers. Screen printing of glass frit paste is usually performed on less sensitive, less critical wafers, normally the capping wafer, because screen printing is a rough process involving the mechanical contact of the screen printing mesh and the wafer. However, for some applications in which contactless patterning of glass frit materials on the device wafers are preferred (e.g., 3D topographies, micro-lens and optics integration) jet dispensing could be a promising approach. Consequently, in this study, wafer-level jetting of glass frit materials on silicon wafers was proposed and investigated. The jetting parameters such as jetting distance, power and temperature were optimized for a glass frit paste. Additionally, the effect of jetted pitch size on the bond-line thickness was assessed. The wafers with jetted glass frit pastes were conclusively bonded in low vacuum and characterized. As a single-step (non-contact) additive approach, the jet printing of glass frit was revealed to be a straightforward, cost-effective and flexible approach with several implications for hermetic packaging.

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“…Insufficient bonding pressure also causes the occurrence of voids at the uneven bonding interface [11]. For the native silicon substrate and a cap wafer without an intermediate layer such as oxide and nitride, the formation of small spherical lead precipitations in the fracture plane results in a large number of voids [12,13]. Ser Choong Chong et al [14] found that after annealing the oxide layer on the cap layer before bonding, there were almost no holes in the interface between the glass paste ring and the cap layer.…”

Section: Introductionmentioning

confidence: 99%

Void Suppression in Glass Frit Bonding Via Three-Step Annealing Process

et al. 2022

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In this work, void formation was systematically observed for the glass frit bonding technique as a function of the annealing temperature, annealing time, and annealing ambient. High annealing temperature and long annealing time were adopted to reach the maximum heat flux to avoid voids/bubbles. As demonstrated in the experiments, the voids appearing during glass frit bonding are related to the quantity of byproducts from the combustion of organic matter. The experimental results indicate that solely in air, under vacuum, or annealed for short time, the combustion products cannot be fully degassed, and voids occur. It was shown that the alternating three-step conditioning process including glass liquid forming in air, bubble removal under vacuum, and void filling-up in air can lead to void-free and uniform wafer bonding. The glass frit bonding samples with lots of voids/bubbles were compared to the ones without any defects.

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Mechanical Characterization and Micro Structure Diagnostics of Glass Frit Bonded Interfaces

Cited by 11 publications

References 2 publications

An Experimental and Numerical Study on Glass Frit Wafer-to-Wafer Bonding

An Experimental and Numerical Study on Glass Frit Wafer-to-Wafer Bonding

Glass Frit Jetting for Advanced Wafer-Level Hermetic Packaging

Void Suppression in Glass Frit Bonding Via Three-Step Annealing Process

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