Au-In-based Hermetic Sealing for MEMS Packaging for Down-Hole Application

Chidambaram, Vivek; Chen, Bangtao; Gan, Chee Lip; Woo, Daniel Rhee Min

doi:10.1007/s11664-014-3131-4

Cited by 14 publications

(7 citation statements)

References 6 publications

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“…Successful SLID bonds utilizing the Cu-Sn system have been carried out at temperatures around 300ºC [2,3,[8][9][10][11][12]. Additionally, several other binary material systems like, Ag-In [13][14][15], Au-In [16][17][18], Cu-In [19], Ag-Sn [20,21], Ni-Sn [22,23], and Au-Sn [24][25][26][27][28][29][30][31] have also demonstrated potential for SLID bonding. Most of these systems require bonding temperatures close to 300ºC, which already is clearly lower than the typical temperatures required in the most commonly utilized eutectic (like Al-Ge), anodic and glass-frit bonding processes [1].…”

Section: Introductionmentioning

confidence: 99%

Demonstrating 170 °C Low-Temperature Cu–In–Sn Wafer-Level Solid Liquid Interdiffusion Bonding

Vuorinen

Ross

Klami

et al. 2022

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

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The wafer-level Solid Liquid Interdiffusion (SLID) bonds carried out for this work take advantage of the Cu-In-Sn ternary system to achieve low temperature interconnections. The 100mm Si wafers had µ-bumps from 250µm down to 10µm fabricated by consecutive electrochemical deposition of Cu, Sn and In layers. The optimized wafer-level bonding processes were carried out by EV Group and Aalto University across a range of temperatures from 250C down to 170C. Even though some process quality related challenges were observed, it could be verified that high strength bonds with low defect content can be achieved even at a low bonding temperature of 170C with an acceptable 1-hour wafer-level bonding duration. The microstructural analysis revealed that the bonding temperature significantly impacts the obtained phase structure as well as the number of defects. A higher (250C) bonding temperature led to the formation of Cu3Sn phase in addition to Cu6(Sn,In)5 and resulted in several voids at Cu3Sn|Cu interface. On the other hand, with lower (200C and 170C) bonding temperatures the interconnection microstructure was composed purely of void free Cu6(Sn,In)5. The mechanical testing results revealed the clear impact of bonding quality on the interconnection strength.

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Section: Introductionmentioning

confidence: 99%

Demonstrating 170 °C Low-Temperature Cu–In–Sn Wafer-Level Solid Liquid Interdiffusion Bonding

Vuorinen

Ross

Klami

et al. 2022

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

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“…Thus, it can ensure devices withstand high temperature operations without failing [7]. Presently, many systems have been proposed, such as Cu-Sn [8], Ag-Sn [9], Au-Sn [10], Ni-Sn [11] and In-based systems [3,7], and the mechanism of IMCs growth and thermal-mechanical reliabilities have been investigated. It is found that Ag 3 Sn compounds have the best ductility in above systems [12], and both shear marks and dimples have ever been observed on the fracture surface of Ag 3 Sn joint [13].…”

Section: Introductionmentioning

confidence: 99%

Microstructure characterization and mechanical behavior for Ag3Sn joint produced by foil-based TLP bonding in air atmosphere

Shao

Bao

et al. 2017

Materials Science and Engineering: A

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Low-temperature transient liquid phase (TLP) bonding for Ag-plated substrates was systematically investigated by using foil-based interlayer of pure Sn foil or preformed Sn/Cu/Sn sandwich structure in air atmosphere. The influences of bonding process, such as bonding temperature, bonding time and foil thickness, on the microstructure characterization and mechanical behavior of TLP joint were discussed. Experimental results show that Ag-plated substrates can be successfully TLP bonded in air atmosphere by the protection of flux. The formation of pores in intermetallic compounds (IMCs) is a serious problem for Ag/Sn/Ag TLP bonding, which is attributed to the volume shrinkage of isolated Sn areas during isothermal solidification. Prolonging homogenization time, properly increasing bonding pressure, decreasing temperature, or reducing interlayer thickness can effectively reduce the shrinkage porosity, but is still incapable of eliminating pores thoroughly. Both shear bands and intergranular facets are simultaneously observed on the fracture surface of Ag 3 Sn joint. Since the micro voids distributing along Ag 3 Sn grain boundaries weaken the cohesion strength between two neighboring Ag 3 Sn grains in some areas. Using preformed Sn/Cu/Sn interlayer is available to enhance the mechanical integrity, which is strongly depended on the Cu thickness and Sn thickness. The joint shear strength can be increased by even more than 100% by the introduction of Cu foil. Moreover, the remained Cu layer in the IMCs can act as a buffer layer during fracture process, leading to the improvement of the ductility of TLP joint.

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“…Ag, Au, Cu, Co or Ni), (3) intermetallic compounds (IMCs) formation that leads to isothermal solidification and (4) homogenization of the interconnection structure. Au-Sn and Cu-Sn based metallurgies are the most commonly utilized material options for SLID out of the several different demonstrated binary systems; Ag-In, [6][7][8] Au-In, 3,[9][10][11][12][13][14] Cu-In, 15 Ag-Sn, 16,17 Ni-Sn, 3,[18][19][20] Au-Sn [21][22][23][24][25][26][27][28] and Cu-Sn. 5,[29][30][31][32][33][34][35][36][37][38] Au-Sn and Cu-Sn systems have been demonstrated to form mechanically and chemically reliable bonds at bonding temperatures close to 300°C.…”

Section: Introductionmentioning

confidence: 99%

Wafer Level Solid Liquid Interdiffusion Bonding: Formation and Evolution of Microstructures

Vuorinen

Dong

Ross

et al. 2020

Journal of Elec Materi

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Wafer-level solid liquid interdiffusion (SLID) bonding, also known as transient liquid-phase bonding, is becoming an increasingly attractive method for industrial usage since it can provide simultaneous formation of electrical interconnections and hermetic encapsulation for microelectromechanical systems. Additionally, SLID is utilized in die-attach bonding for electronic power components. In order to ensure the functionality and reliability of the devices, a fundamental understanding of the formation and evolution of interconnection microstructures, as well as global and local stresses, is of utmost importance. In this work a low-temperature Cu-In-Sn based SLID bonding process is presented. It was discovered that by introducing In to the traditional Cu-Sn metallurgy as an additional alloying element, it is possible to significantly decrease the bonding temperature. Decreasing the bonding temperature results in lower CTE induced global residual stresses. However, there are still several open issues to be studied regarding the effects of dissolved In on the physical properties of the Cu-Sn intermetallics. Additionally, partially metastable microstructures were observed in bonded samples that did not significantly evolve during thermal annealing. This indicates the Cu-In-Sn SLID bond microstructure is extremely stable.

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Au-In-based Hermetic Sealing for MEMS Packaging for Down-Hole Application

Cited by 14 publications

References 6 publications

Demonstrating 170 °C Low-Temperature Cu–In–Sn Wafer-Level Solid Liquid Interdiffusion Bonding

Demonstrating 170 °C Low-Temperature Cu–In–Sn Wafer-Level Solid Liquid Interdiffusion Bonding

Microstructure characterization and mechanical behavior for Ag3Sn joint produced by foil-based TLP bonding in air atmosphere

Wafer Level Solid Liquid Interdiffusion Bonding: Formation and Evolution of Microstructures

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