The Experts below are selected from a list of 555 Experts worldwide ranked by ideXlab platform

Shiv Govind Singh - One of the best experts on this subject based on the ideXlab platform.

  • surface density gradient engineering precedes enhanced diffusion drives cmos in line process flow compatible cu cu Thermocompression Bonding at 75 c
    IEEE Transactions on Device and Materials Reliability, 2019
    Co-Authors: Asisa Kumar Panigrahy, Tamal Ghosh, Siva Rama Krishna Vanjari, Shiv Govind Singh
    Abstract:

    Diffusion is one of the most critical and key factor for achieving low temperature and low pressure Thermocompression Bonding. In this work, we propose a novel concept of modifying density conditions within the Cu films. The density of film was varied by varying the DC bias applied for the sputter deposition. While two samples of different densities are brought in contact with each other, Cu atoms from the thin film having higher density of atoms tends to interdiffuse into the thin film having lower density. Optimal dc biasing conditions for pair of wafers were figured out based on the pre-Bonding characterizations and it yielded an excellent Bonding at Sub 100 °C. No observable bond interface X-TEM images and bond strength of 164 MPa confirmed the quality of Bonding. Furthermore, bonded structure undergone various reliability tests include multiple current stressing test, temperature cycling test and relative humidity test confirms Cu-Cu Bonding using surface density gradient engineering is stable and promising candidate for future 3D IC integration applications.

  • Achieving of Intensified Conductive Interconnections for Flex-on-Flex by Using Metal Passivated Copper – Copper Thermocompression Bonding
    2018 IEEE 68th Electronic Components and Technology Conference (ECTC), 2018
    Co-Authors: Hemanth C. Kuma, Siva Rama Krishna Vanjari, Asisa Kuma Panigrahi, Satish Onam, Nirupam Paul, Shiv Govind Singh
    Abstract:

    There is a gradual increase in demand for flexible electronics due to the way it is going to empower the end user - to bent, roll/fold and arrange randomly in 3-D space, the devices without sacrificing the performance and reliability of devices, in a trend focused towards ever shrinking device footprint area. One of the prime mover towards realizing flexible electronics is interconnect scaling, which is motivating us to move towards three-dimensional interconnect integration. In this paper, we propose the interconnection of two flexible-flexible substrates by Thermocompression Bonding between copper-to-copper, with their surface passivated with palladium, at low temperature and low pressure, to overcome the limitations imposed by conventional anisotropic conductive film (ACF) and nonconductive paste (NCP) approaches. The enhancement in interdiffusion of atomic species between the two surfaces, at low temperature and pressure, is possible only with unoxidized surface which has low RMS roughness or with surface which has varied film density. We have systematically optimized the thickness of palladium passivation layer for high quality Cu-Cu Bonding, at low temperature of 140 oC and at low pressure of 5 bar. 2.06 nm RMS surface roughness was observed for Palladium passivation layer when its thickness was optimized at 5 nm, which made bonded Cu-Cu junction interface free from any copper oxide, as it was confirmed by X-ray Diffraction (XRD) and Energy Dispersive Spectroscopy (EDS) analysis. To confirm the quality of bonded interface, the samples were subjected to stress by folding just after Thermocompression Bonding. Absence of any voids between the interfaces during Scanning Acoustic Microscopy (SAM) imaging confirms the superior quality of Cu-Cu Bonding. The bonded interface image from cross-sectional Scanning Electron Microcopy (X-SEM) further reaffirms the quality of interface. Besides, very low contact resistance of ~2 E-7 ? - cm2 obtained for a fabricated daisy chain pattern with 70 um pitch and 100 um × 100 um Bonding contact, in addition, confirms the good quality of Bonding interface. The demonstrated Bonding approach with metal passivated interconnect technique will be one of the prime contestant for future high bandwidth applications.

  • Optimized ultra-thin Manganin alloy passivated fine-pitch damascene compatible Cu-Cu Bonding at sub 200°C for 3D IC integration
    2017 5th International Workshop on Low Temperature Bonding for 3D Integration (LTB-3D), 2017
    Co-Authors: Asisa Kumar Panigrahi, Hemanth C. Kumar, Tamal Ghosh, Siva Rama Krishna Vanjari, Shiv Govind Singh
    Abstract:

    Enhanced Cu diffusion, Cu surface passivation, and surface smoothness at the Bonding interface are the key requirements for high quality Copper-Copper (Cu-Cu) Thermocompression Bonding. In our previous work, we have demonstrated the usage of optimized Manganin metal alloy of 3 nm not only helps in passivating the Cu surface even at high temperature (

  • demonstration of sub 150 c cu cu Thermocompression Bonding for 3d ic applications utilizing an ultra thin layer of manganin alloy as an effective surface passivation layer
    Materials Letters, 2017
    Co-Authors: Asisa Kumar Panigrahi, Tamal Ghosh, Siva Rama Krishna Vanjari, Shiv Govind Singh
    Abstract:

    Damascene process compatible Copper (Cu) surface passivation, ultra-smooth surface and enhanced Cu diffusion at the Bonding interface are the key requirements for high quality, low temperature and low pressure Cu-Cu Bonding for 3D integration applications. Manganin alloy deployed in this work as a passivation layer, performs dual role of protecting Cu surface from oxidation even at higher temperature ( oriented plane formation with Manganin alloy passivated Cu surface. All the aforementioned factors are key enablers in enhancing diffusion of Cu across the Bonding interface. This led to high quality Cu-Cu Thermocompression Bonding at sub 150˚C temperature and at a nominal contact force of 5 kN. Very low specific contact resistance of 1.45 × 10-7 Ω-cm2 and excellent bond strength of 186 MPa is clear evidence of the efficacy of optimized ultra-thin Manganin alloy as a passivation layer.

  • optimized ultra thin manganin alloy passivated fine pitch damascene compatible cu cu Bonding at sub 200 c for 3d ic integration
    2017 5th International Workshop on Low Temperature Bonding for 3D Integration (LTB-3D), 2017
    Co-Authors: Asisa Kumar Panigrahi, Hemanth C. Kumar, Tamal Ghosh, Siva Rama Krishna Vanjari, Shiv Govind Singh
    Abstract:

    Enhanced Cu diffusion, Cu surface passivation, and surface smoothness at the Bonding interface are the key requirements for high quality Copper-Copper (Cu-Cu) Thermocompression Bonding. In our previous work, we have demonstrated the usage of optimized Manganin metal alloy of 3 nm not only helps in passivating the Cu surface even at high temperature (<300°C) but also reduces the surface roughness to about 0.8 nm which substantially led to high quality Cu-Cu Bonding. In this paper, we demonstrate an ultra-fine pitch Cu-Cu Thermocompression Bonding using an optimized ultra-thin damascene compatible Manganin metal alloy passivation. This engineering surface passivation approach has led to high quality Bonding at sub 200° C temperature and a nominal contact force of 4kN. Furthermore, electrical characterization using modified kelvin structure, and reliability assessment of this bonded structure was investigated under multiple current stressing, temperature cycling test and the results indicate excellent stability without electrical performance degradation. This practical finding has immense potential to leads into practical realization of 3D IC integration.

Siva Rama Krishna Vanjari - One of the best experts on this subject based on the ideXlab platform.

  • surface density gradient engineering precedes enhanced diffusion drives cmos in line process flow compatible cu cu Thermocompression Bonding at 75 c
    IEEE Transactions on Device and Materials Reliability, 2019
    Co-Authors: Asisa Kumar Panigrahy, Tamal Ghosh, Siva Rama Krishna Vanjari, Shiv Govind Singh
    Abstract:

    Diffusion is one of the most critical and key factor for achieving low temperature and low pressure Thermocompression Bonding. In this work, we propose a novel concept of modifying density conditions within the Cu films. The density of film was varied by varying the DC bias applied for the sputter deposition. While two samples of different densities are brought in contact with each other, Cu atoms from the thin film having higher density of atoms tends to interdiffuse into the thin film having lower density. Optimal dc biasing conditions for pair of wafers were figured out based on the pre-Bonding characterizations and it yielded an excellent Bonding at Sub 100 °C. No observable bond interface X-TEM images and bond strength of 164 MPa confirmed the quality of Bonding. Furthermore, bonded structure undergone various reliability tests include multiple current stressing test, temperature cycling test and relative humidity test confirms Cu-Cu Bonding using surface density gradient engineering is stable and promising candidate for future 3D IC integration applications.

  • Diffusion Enhanced Drive Sub 100 °C Wafer Level Fine-Pitch Cu-Cu Thermocompression Bonding for 3D IC Integration
    2019 IEEE 69th Electronic Components and Technology Conference (ECTC), 2019
    Co-Authors: Asisa Kumar Panigrahy, Tamal Ghosh, Satish Bonam, Siva Rama Krishna Vanjari
    Abstract:

    One of the primary and critical requirements for high quality wafer level Thermocompression Copper-Copper (Cu-Cu) Bonding is the fast diffusion of Cu atoms across the boundary between two Bonding layers. In this paper, we demonstrate low temperature, low pressure and fine pitch Cu-Cu Thermocompression Bonding by enhancing intrinsic diffusivity at the Bonding interface by stress gradient. Stress in the Cu surface was fixed up by simply varying the Ar pressure during physical deposition using the sputtering tool and observed clearly that one of the other deposited wafers had opposite stress and highest differential stress not only led to fine-pitch Bonding at sub 100°C with very low external pressure of 0.25 MPa. Retention of stress even in the smaller patterns was clearly observed using conventional non-destructive wafer bow technique and further corroborated using solid mechanic module of COMSOL Multiphysics simulator. The quality of stress engineered fine-pitch bonded sample was examined using the pull test and Idonus Wafer Bonder IR Inspection (WBI) tool. Furthermore, the absence of voids and defect free Bonding interface clearly opens up realistic chances for three dimensional (3D) IC integration. Moreover, this novel stress tailoring Cu surface modification prior to Bonding is the primary contestant for future heterogeneous integration.

  • direct cmos in line process flow compatible sub 100 c cu cu Thermocompression Bonding using stress engineering
    Electronic Materials Letters, 2018
    Co-Authors: Asisa Kumar Panigrahi, Hemanth C. Kumar, Tamal Ghosh, Siva Rama Krishna Vanjari
    Abstract:

    Diffusion of atoms across the boundary between two Bonding layers is the key for achieving excellent Thermocompression Wafer on Wafer Bonding. In this paper, we demonstrate a novel mechanism to increase the diffusion across the Bonding interface and also shows the CMOS in-line process flow compatible Sub 100 °C Cu–Cu Bonding which is devoid of Cu surface treatment prior to Bonding. The stress in sputtered Cu thin films was engineered by adjusting the Argon in-let pressure in such a way that one film had a compressive stress while the other film had tensile stress. Due to this stress gradient, a nominal pressure (2 kN) and temperature (75 °C) was enough to achieve a good quality Thermocompression Bonding having a bond strength of 149 MPa and very low specific contact resistance of 1.5 × 10−8 Ω-cm2. These excellent mechanical and electrical properties are resultant of a high quality Cu–Cu Bonding having grain growth between the Cu films across the boundary and extended throughout the bonded region as revealed by Cross-sectional Transmission Electron Microscopy. In addition, reliability assessment of Cu–Cu Bonding with stress engineering was demonstrated using multiple current stressing and temperature cycling test, suggests excellent reliable Bonding without electrical performance degradation.

  • Achieving of Intensified Conductive Interconnections for Flex-on-Flex by Using Metal Passivated Copper – Copper Thermocompression Bonding
    2018 IEEE 68th Electronic Components and Technology Conference (ECTC), 2018
    Co-Authors: Hemanth C. Kuma, Siva Rama Krishna Vanjari, Asisa Kuma Panigrahi, Satish Onam, Nirupam Paul, Shiv Govind Singh
    Abstract:

    There is a gradual increase in demand for flexible electronics due to the way it is going to empower the end user - to bent, roll/fold and arrange randomly in 3-D space, the devices without sacrificing the performance and reliability of devices, in a trend focused towards ever shrinking device footprint area. One of the prime mover towards realizing flexible electronics is interconnect scaling, which is motivating us to move towards three-dimensional interconnect integration. In this paper, we propose the interconnection of two flexible-flexible substrates by Thermocompression Bonding between copper-to-copper, with their surface passivated with palladium, at low temperature and low pressure, to overcome the limitations imposed by conventional anisotropic conductive film (ACF) and nonconductive paste (NCP) approaches. The enhancement in interdiffusion of atomic species between the two surfaces, at low temperature and pressure, is possible only with unoxidized surface which has low RMS roughness or with surface which has varied film density. We have systematically optimized the thickness of palladium passivation layer for high quality Cu-Cu Bonding, at low temperature of 140 oC and at low pressure of 5 bar. 2.06 nm RMS surface roughness was observed for Palladium passivation layer when its thickness was optimized at 5 nm, which made bonded Cu-Cu junction interface free from any copper oxide, as it was confirmed by X-ray Diffraction (XRD) and Energy Dispersive Spectroscopy (EDS) analysis. To confirm the quality of bonded interface, the samples were subjected to stress by folding just after Thermocompression Bonding. Absence of any voids between the interfaces during Scanning Acoustic Microscopy (SAM) imaging confirms the superior quality of Cu-Cu Bonding. The bonded interface image from cross-sectional Scanning Electron Microcopy (X-SEM) further reaffirms the quality of interface. Besides, very low contact resistance of ~2 E-7 ? - cm2 obtained for a fabricated daisy chain pattern with 70 um pitch and 100 um × 100 um Bonding contact, in addition, confirms the good quality of Bonding interface. The demonstrated Bonding approach with metal passivated interconnect technique will be one of the prime contestant for future high bandwidth applications.

  • Optimized ultra-thin Manganin alloy passivated fine-pitch damascene compatible Cu-Cu Bonding at sub 200°C for 3D IC integration
    2017 5th International Workshop on Low Temperature Bonding for 3D Integration (LTB-3D), 2017
    Co-Authors: Asisa Kumar Panigrahi, Hemanth C. Kumar, Tamal Ghosh, Siva Rama Krishna Vanjari, Shiv Govind Singh
    Abstract:

    Enhanced Cu diffusion, Cu surface passivation, and surface smoothness at the Bonding interface are the key requirements for high quality Copper-Copper (Cu-Cu) Thermocompression Bonding. In our previous work, we have demonstrated the usage of optimized Manganin metal alloy of 3 nm not only helps in passivating the Cu surface even at high temperature (

Tamal Ghosh - One of the best experts on this subject based on the ideXlab platform.

  • surface density gradient engineering precedes enhanced diffusion drives cmos in line process flow compatible cu cu Thermocompression Bonding at 75 c
    IEEE Transactions on Device and Materials Reliability, 2019
    Co-Authors: Asisa Kumar Panigrahy, Tamal Ghosh, Siva Rama Krishna Vanjari, Shiv Govind Singh
    Abstract:

    Diffusion is one of the most critical and key factor for achieving low temperature and low pressure Thermocompression Bonding. In this work, we propose a novel concept of modifying density conditions within the Cu films. The density of film was varied by varying the DC bias applied for the sputter deposition. While two samples of different densities are brought in contact with each other, Cu atoms from the thin film having higher density of atoms tends to interdiffuse into the thin film having lower density. Optimal dc biasing conditions for pair of wafers were figured out based on the pre-Bonding characterizations and it yielded an excellent Bonding at Sub 100 °C. No observable bond interface X-TEM images and bond strength of 164 MPa confirmed the quality of Bonding. Furthermore, bonded structure undergone various reliability tests include multiple current stressing test, temperature cycling test and relative humidity test confirms Cu-Cu Bonding using surface density gradient engineering is stable and promising candidate for future 3D IC integration applications.

  • Diffusion Enhanced Drive Sub 100 °C Wafer Level Fine-Pitch Cu-Cu Thermocompression Bonding for 3D IC Integration
    2019 IEEE 69th Electronic Components and Technology Conference (ECTC), 2019
    Co-Authors: Asisa Kumar Panigrahy, Tamal Ghosh, Satish Bonam, Siva Rama Krishna Vanjari
    Abstract:

    One of the primary and critical requirements for high quality wafer level Thermocompression Copper-Copper (Cu-Cu) Bonding is the fast diffusion of Cu atoms across the boundary between two Bonding layers. In this paper, we demonstrate low temperature, low pressure and fine pitch Cu-Cu Thermocompression Bonding by enhancing intrinsic diffusivity at the Bonding interface by stress gradient. Stress in the Cu surface was fixed up by simply varying the Ar pressure during physical deposition using the sputtering tool and observed clearly that one of the other deposited wafers had opposite stress and highest differential stress not only led to fine-pitch Bonding at sub 100°C with very low external pressure of 0.25 MPa. Retention of stress even in the smaller patterns was clearly observed using conventional non-destructive wafer bow technique and further corroborated using solid mechanic module of COMSOL Multiphysics simulator. The quality of stress engineered fine-pitch bonded sample was examined using the pull test and Idonus Wafer Bonder IR Inspection (WBI) tool. Furthermore, the absence of voids and defect free Bonding interface clearly opens up realistic chances for three dimensional (3D) IC integration. Moreover, this novel stress tailoring Cu surface modification prior to Bonding is the primary contestant for future heterogeneous integration.

  • direct cmos in line process flow compatible sub 100 c cu cu Thermocompression Bonding using stress engineering
    Electronic Materials Letters, 2018
    Co-Authors: Asisa Kumar Panigrahi, Hemanth C. Kumar, Tamal Ghosh, Siva Rama Krishna Vanjari
    Abstract:

    Diffusion of atoms across the boundary between two Bonding layers is the key for achieving excellent Thermocompression Wafer on Wafer Bonding. In this paper, we demonstrate a novel mechanism to increase the diffusion across the Bonding interface and also shows the CMOS in-line process flow compatible Sub 100 °C Cu–Cu Bonding which is devoid of Cu surface treatment prior to Bonding. The stress in sputtered Cu thin films was engineered by adjusting the Argon in-let pressure in such a way that one film had a compressive stress while the other film had tensile stress. Due to this stress gradient, a nominal pressure (2 kN) and temperature (75 °C) was enough to achieve a good quality Thermocompression Bonding having a bond strength of 149 MPa and very low specific contact resistance of 1.5 × 10−8 Ω-cm2. These excellent mechanical and electrical properties are resultant of a high quality Cu–Cu Bonding having grain growth between the Cu films across the boundary and extended throughout the bonded region as revealed by Cross-sectional Transmission Electron Microscopy. In addition, reliability assessment of Cu–Cu Bonding with stress engineering was demonstrated using multiple current stressing and temperature cycling test, suggests excellent reliable Bonding without electrical performance degradation.

  • Optimized ultra-thin Manganin alloy passivated fine-pitch damascene compatible Cu-Cu Bonding at sub 200°C for 3D IC integration
    2017 5th International Workshop on Low Temperature Bonding for 3D Integration (LTB-3D), 2017
    Co-Authors: Asisa Kumar Panigrahi, Hemanth C. Kumar, Tamal Ghosh, Siva Rama Krishna Vanjari, Shiv Govind Singh
    Abstract:

    Enhanced Cu diffusion, Cu surface passivation, and surface smoothness at the Bonding interface are the key requirements for high quality Copper-Copper (Cu-Cu) Thermocompression Bonding. In our previous work, we have demonstrated the usage of optimized Manganin metal alloy of 3 nm not only helps in passivating the Cu surface even at high temperature (

  • demonstration of sub 150 c cu cu Thermocompression Bonding for 3d ic applications utilizing an ultra thin layer of manganin alloy as an effective surface passivation layer
    Materials Letters, 2017
    Co-Authors: Asisa Kumar Panigrahi, Tamal Ghosh, Siva Rama Krishna Vanjari, Shiv Govind Singh
    Abstract:

    Damascene process compatible Copper (Cu) surface passivation, ultra-smooth surface and enhanced Cu diffusion at the Bonding interface are the key requirements for high quality, low temperature and low pressure Cu-Cu Bonding for 3D integration applications. Manganin alloy deployed in this work as a passivation layer, performs dual role of protecting Cu surface from oxidation even at higher temperature ( oriented plane formation with Manganin alloy passivated Cu surface. All the aforementioned factors are key enablers in enhancing diffusion of Cu across the Bonding interface. This led to high quality Cu-Cu Thermocompression Bonding at sub 150˚C temperature and at a nominal contact force of 5 kN. Very low specific contact resistance of 1.45 × 10-7 Ω-cm2 and excellent bond strength of 186 MPa is clear evidence of the efficacy of optimized ultra-thin Manganin alloy as a passivation layer.

Asisa Kumar Panigrahi - One of the best experts on this subject based on the ideXlab platform.

  • direct cmos in line process flow compatible sub 100 c cu cu Thermocompression Bonding using stress engineering
    Electronic Materials Letters, 2018
    Co-Authors: Asisa Kumar Panigrahi, Hemanth C. Kumar, Tamal Ghosh, Siva Rama Krishna Vanjari
    Abstract:

    Diffusion of atoms across the boundary between two Bonding layers is the key for achieving excellent Thermocompression Wafer on Wafer Bonding. In this paper, we demonstrate a novel mechanism to increase the diffusion across the Bonding interface and also shows the CMOS in-line process flow compatible Sub 100 °C Cu–Cu Bonding which is devoid of Cu surface treatment prior to Bonding. The stress in sputtered Cu thin films was engineered by adjusting the Argon in-let pressure in such a way that one film had a compressive stress while the other film had tensile stress. Due to this stress gradient, a nominal pressure (2 kN) and temperature (75 °C) was enough to achieve a good quality Thermocompression Bonding having a bond strength of 149 MPa and very low specific contact resistance of 1.5 × 10−8 Ω-cm2. These excellent mechanical and electrical properties are resultant of a high quality Cu–Cu Bonding having grain growth between the Cu films across the boundary and extended throughout the bonded region as revealed by Cross-sectional Transmission Electron Microscopy. In addition, reliability assessment of Cu–Cu Bonding with stress engineering was demonstrated using multiple current stressing and temperature cycling test, suggests excellent reliable Bonding without electrical performance degradation.

  • Optimized ultra-thin Manganin alloy passivated fine-pitch damascene compatible Cu-Cu Bonding at sub 200°C for 3D IC integration
    2017 5th International Workshop on Low Temperature Bonding for 3D Integration (LTB-3D), 2017
    Co-Authors: Asisa Kumar Panigrahi, Hemanth C. Kumar, Tamal Ghosh, Siva Rama Krishna Vanjari, Shiv Govind Singh
    Abstract:

    Enhanced Cu diffusion, Cu surface passivation, and surface smoothness at the Bonding interface are the key requirements for high quality Copper-Copper (Cu-Cu) Thermocompression Bonding. In our previous work, we have demonstrated the usage of optimized Manganin metal alloy of 3 nm not only helps in passivating the Cu surface even at high temperature (

  • demonstration of sub 150 c cu cu Thermocompression Bonding for 3d ic applications utilizing an ultra thin layer of manganin alloy as an effective surface passivation layer
    Materials Letters, 2017
    Co-Authors: Asisa Kumar Panigrahi, Tamal Ghosh, Siva Rama Krishna Vanjari, Shiv Govind Singh
    Abstract:

    Damascene process compatible Copper (Cu) surface passivation, ultra-smooth surface and enhanced Cu diffusion at the Bonding interface are the key requirements for high quality, low temperature and low pressure Cu-Cu Bonding for 3D integration applications. Manganin alloy deployed in this work as a passivation layer, performs dual role of protecting Cu surface from oxidation even at higher temperature ( oriented plane formation with Manganin alloy passivated Cu surface. All the aforementioned factors are key enablers in enhancing diffusion of Cu across the Bonding interface. This led to high quality Cu-Cu Thermocompression Bonding at sub 150˚C temperature and at a nominal contact force of 5 kN. Very low specific contact resistance of 1.45 × 10-7 Ω-cm2 and excellent bond strength of 186 MPa is clear evidence of the efficacy of optimized ultra-thin Manganin alloy as a passivation layer.

  • optimized ultra thin manganin alloy passivated fine pitch damascene compatible cu cu Bonding at sub 200 c for 3d ic integration
    2017 5th International Workshop on Low Temperature Bonding for 3D Integration (LTB-3D), 2017
    Co-Authors: Asisa Kumar Panigrahi, Hemanth C. Kumar, Tamal Ghosh, Siva Rama Krishna Vanjari, Shiv Govind Singh
    Abstract:

    Enhanced Cu diffusion, Cu surface passivation, and surface smoothness at the Bonding interface are the key requirements for high quality Copper-Copper (Cu-Cu) Thermocompression Bonding. In our previous work, we have demonstrated the usage of optimized Manganin metal alloy of 3 nm not only helps in passivating the Cu surface even at high temperature (<300°C) but also reduces the surface roughness to about 0.8 nm which substantially led to high quality Cu-Cu Bonding. In this paper, we demonstrate an ultra-fine pitch Cu-Cu Thermocompression Bonding using an optimized ultra-thin damascene compatible Manganin metal alloy passivation. This engineering surface passivation approach has led to high quality Bonding at sub 200° C temperature and a nominal contact force of 4kN. Furthermore, electrical characterization using modified kelvin structure, and reliability assessment of this bonded structure was investigated under multiple current stressing, temperature cycling test and the results indicate excellent stability without electrical performance degradation. This practical finding has immense potential to leads into practical realization of 3D IC integration.

Schjølberg-henriksen Kari - One of the best experts on this subject based on the ideXlab platform.

  • The Synergistic Roles of Temperature and Pressure in Thermo-Compression Bonding of Au
    'The Electrochemical Society', 2018
    Co-Authors: Ambhore Pranav, Malik Nishant, Schjølberg-henriksen Kari, Beekley Brett, Mani Karthick, Iyer, Subramanian S., Goorsky, Mark S.
    Abstract:

    Abstract Au-Au Thermocompression Bonding is a widely used technique for a variety of applications including hermetic sealing and packaging at a fine pitch. We have investigated the roles of pressure and temperature individually at different pressures (15 -100 MPa) and temperatures (150 and 250° C) of sputter deposited 1.2 μm thick Au thin films using a flattening technique. The initial surface root mean square (RMS) roughness of deposited films was 3-5 nm. Void morphology and the evolution of the interface was studied using atomic force microscopy. Power spectral density function plots were used to study variation in asperities at the surface. The void morphology and evolution was different when flattening and Bonding at different temperatures and pressures.acceptedVersio

  • The Synergistic Roles of Temperature and Pressure in Thermo-Compression Bonding of Au
    Electrochemical Society, 2018
    Co-Authors: Ambhore Pranav, Malik Nishant, Schjølberg-henriksen Kari, Beekley Brett, Mani Karthick, Iyer, Subramanian S., Goorsky, Mark S.
    Abstract:

    Abstract Au-Au Thermocompression Bonding is a widely used technique for a variety of applications including hermetic sealing and packaging at a fine pitch. We have investigated the roles of pressure and temperature individually at different pressures (15 -100 MPa) and temperatures (150 and 250° C) of sputter deposited 1.2 μm thick Au thin films using a flattening technique. The initial surface root mean square (RMS) roughness of deposited films was 3-5 nm. Void morphology and the evolution of the interface was studied using atomic force microscopy. Power spectral density function plots were used to study variation in asperities at the surface. The void morphology and evolution was different when flattening and Bonding at different temperatures and pressures

  • Texture of Al films for wafer-level Thermocompression Bonding
    'Elsevier BV', 2017
    Co-Authors: Malik Nishant, Venkatachalapathy Vishnukanthan, Dall Wilhelm, Schjølberg-henriksen Kari, Poppe, Erik Utne, Taklo, Maaike M. Visser, Finstad Terje
    Abstract:

    Properties of aluminum thin films for Thermocompression Bonding have been studied in terms of surface roughness, grain size, and grain orientation by AFM, SEM, XRD and EBSD for Thermocompression Bonding. Al films were sputter deposited directly on Si and thermally oxidized Si wafers, respectively. The resulting Si/Al and Si/SiO2/Al sample types were compared after annealing (300–550 °C) in vacuum. The Si/SiO2/Al film samples showed higher surface roughness than the Si/Al samples. The as-deposited films had (111) preferred orientation, while (100) and (110) oriented Al grains were also present in Si/SiO2/Al samples. The Si/SiO2/Al samples and Si/Al sample annealed at 550 °C had a conical texture. The observed evolution of the grain structure with annealing temperature is discussed in terms of native oxide, surface roughness, diffusivity and grain orientation dependent mechanical properties in order to shine light on previously observed differences in Alsingle bondAl Thermocompression wafer-level Bonding with Si/SiO2/Al and Si/Al wafers.acceptedVersio

  • Characterization of interfacial morphology of low temperature, low pressure Au–Au Thermocompression Bonding
    'Japan Society of Applied Physics', 2017
    Co-Authors: Goorsky, Mark S., Ambhore Pranav, Malik Nishant, Schjølberg-henriksen Kari, Beekley Brett, Bai Tingyu, Mani Karthick, Bajwa Adeel, Iyer, Subramanian S.
    Abstract:

    Au-Au Thermocompression Bonding is a versatile technique of high interest for a variety of applications. We have investigated Au-Au Bonding using sputter deposited Au films under conditions of low temperature (150-250 °C) and low Bonding pressure (∼3 MPa) for short times (15 min). The combination of low temperature and short times is important for applications involving both hermetic sealing and packaging scaling. The initial surface roughness of the Au film was in the 3-5 nm range with peak-to-valley heights of 20-30 nm and a lateral correlation length of ∼400 nm. For samples bonded at 150 °C, the void morphology at the bonded interface was related to the initial surface roughness. The void morphology was different when Bonding at the higher temperatures: the void length (along the bonded interface) decreased significantly but the void height (perpendicular to the interface) increased. These results can be understood in terms of a combination of increased surface Au diffusivity and decreased yield stress and elastic modulus with increased Bonding temperature. © 2018 The Japan Society of Applied Physics.acceptedVersio

  • Non-destructive wafer-level bond defect identification by scanning acoustic microscopy
    'Springer Science and Business Media LLC', 2015
    Co-Authors: Brand Sebastian, Tismer Sebastian, Moe, Sigurd T., Schjølberg-henriksen Kari
    Abstract:

    Metal-based Thermocompression Bonding enables the creation of hermetic seals formed at relatively low processing temperatures and occupying a small portion of the device area. In the current study we have investigated the application of scanning acoustic microscopy (SAM) for assessing the quality of metal Thermocompression bonds, both by evaluating its capabilities of localizing areas of poor Bonding, and by finding defects in the integrity of the bond seal. Wafer laminates containing a test vehicle of sealing frames with pre-defined defects in the bond metal layer were sealed by Au–Au and Al–Al Thermocompression Bonding. Employing SAM, an area of five chips of poor Bonding was identified non-destructively on the Al–Al laminate. Line defects of width 3.6 µm and point defects of diameter 22.4 µm have also been identified by SAM. The dicing yield for sealing frames was above 96 % for all frames of widths 100–400 µm and for both bond metal systems. The average bond strength was 31.5 ± 11.9 MPa for Al–Al Thermocompression bonds and 37.3 ± 9.7 MPa for Au–Au Thermocompression bonds. Scanning acoustic microscopy operates non-destructively and proved to be an extremely useful tool complementing current state-of-the-art methods for bond quality assessment.acceptedVersio