Nondestructive characterization of fusion and plasma activated wafer bonding using mesa and recess structures

Aapo Varpula (Corresponding Author), Tommi Suni, James R. Dekker

    Research output: Contribution to journalArticleScientificpeer-review

    Abstract

    We present two methods for characterization of wafer bonding. They are based on recess and mesa bond test structures with various shapes, measurement of unbonded regions using scanning acoustic microscopy (SAM), and image analysis. The first method maps locally the surface energy across the bonded wafers using the measured deformations around these structures and the finite element method (FEM). The FEM analysis is supported by analytical modeling. The second method uses the measured bonding probabilities of 10-19 nm deep recess bond test structures in investigation of surface interactions and in determination of the average of the surface energy at the wafer level. The present methods and proposed optimized test structures allow the evaluation of surface cleans without destructive, off-line methods such as the crack-opening method, which is employed as a reference. The methods are utilized in the investigation of the effect of O2 and N2 plasma activation and the dilution and temperature of Standard Clean 1 on Si/SiO2 direct bonding. The results from both methods correlate with each other. The bond strength of the annealed wafers is observed to increase in the order 1) O2 plasma, 2) standard SC1 at 65°C, 3) N2 plasma, and 4) dilute SC1 at 45°C.
    Original languageEnglish
    Pages (from-to)P42 - P52
    JournalECS Journal of Solid State Science and Technology
    Volume4
    Issue number2
    DOIs
    Publication statusPublished - 2015
    MoE publication typeA1 Journal article-refereed

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    Wafer bonding
    Fusion reactions
    Plasmas
    Interfacial energy
    Finite element method
    Image analysis
    Dilution
    Chemical activation
    Cracks
    Temperature

    Cite this

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    title = "Nondestructive characterization of fusion and plasma activated wafer bonding using mesa and recess structures",
    abstract = "We present two methods for characterization of wafer bonding. They are based on recess and mesa bond test structures with various shapes, measurement of unbonded regions using scanning acoustic microscopy (SAM), and image analysis. The first method maps locally the surface energy across the bonded wafers using the measured deformations around these structures and the finite element method (FEM). The FEM analysis is supported by analytical modeling. The second method uses the measured bonding probabilities of 10-19 nm deep recess bond test structures in investigation of surface interactions and in determination of the average of the surface energy at the wafer level. The present methods and proposed optimized test structures allow the evaluation of surface cleans without destructive, off-line methods such as the crack-opening method, which is employed as a reference. The methods are utilized in the investigation of the effect of O2 and N2 plasma activation and the dilution and temperature of Standard Clean 1 on Si/SiO2 direct bonding. The results from both methods correlate with each other. The bond strength of the annealed wafers is observed to increase in the order 1) O2 plasma, 2) standard SC1 at 65°C, 3) N2 plasma, and 4) dilute SC1 at 45°C.",
    author = "Aapo Varpula and Tommi Suni and Dekker, {James R.}",
    note = "Project code: 41693",
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    doi = "10.1149/2.0121502jss",
    language = "English",
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    TY - JOUR

    T1 - Nondestructive characterization of fusion and plasma activated wafer bonding using mesa and recess structures

    AU - Varpula, Aapo

    AU - Suni, Tommi

    AU - Dekker, James R.

    N1 - Project code: 41693

    PY - 2015

    Y1 - 2015

    N2 - We present two methods for characterization of wafer bonding. They are based on recess and mesa bond test structures with various shapes, measurement of unbonded regions using scanning acoustic microscopy (SAM), and image analysis. The first method maps locally the surface energy across the bonded wafers using the measured deformations around these structures and the finite element method (FEM). The FEM analysis is supported by analytical modeling. The second method uses the measured bonding probabilities of 10-19 nm deep recess bond test structures in investigation of surface interactions and in determination of the average of the surface energy at the wafer level. The present methods and proposed optimized test structures allow the evaluation of surface cleans without destructive, off-line methods such as the crack-opening method, which is employed as a reference. The methods are utilized in the investigation of the effect of O2 and N2 plasma activation and the dilution and temperature of Standard Clean 1 on Si/SiO2 direct bonding. The results from both methods correlate with each other. The bond strength of the annealed wafers is observed to increase in the order 1) O2 plasma, 2) standard SC1 at 65°C, 3) N2 plasma, and 4) dilute SC1 at 45°C.

    AB - We present two methods for characterization of wafer bonding. They are based on recess and mesa bond test structures with various shapes, measurement of unbonded regions using scanning acoustic microscopy (SAM), and image analysis. The first method maps locally the surface energy across the bonded wafers using the measured deformations around these structures and the finite element method (FEM). The FEM analysis is supported by analytical modeling. The second method uses the measured bonding probabilities of 10-19 nm deep recess bond test structures in investigation of surface interactions and in determination of the average of the surface energy at the wafer level. The present methods and proposed optimized test structures allow the evaluation of surface cleans without destructive, off-line methods such as the crack-opening method, which is employed as a reference. The methods are utilized in the investigation of the effect of O2 and N2 plasma activation and the dilution and temperature of Standard Clean 1 on Si/SiO2 direct bonding. The results from both methods correlate with each other. The bond strength of the annealed wafers is observed to increase in the order 1) O2 plasma, 2) standard SC1 at 65°C, 3) N2 plasma, and 4) dilute SC1 at 45°C.

    U2 - 10.1149/2.0121502jss

    DO - 10.1149/2.0121502jss

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    VL - 4

    SP - P42 - P52

    JO - ECS Journal of Solid State Science and Technology

    JF - ECS Journal of Solid State Science and Technology

    SN - 2162-8769

    IS - 2

    ER -