Thermal Misfit and Diffusion Induced Stresses of Cu-Al Intermetallics in Microelectronics Wire Bonding

Abstract:

The thermosonic bonding technique is a widely used method for Cu wire interconnections. However, issues arise due to volumetric changes in intermetallic compounds (IMCs) formed at the Cu-Al bonding interface, leading to voids in the Cu-Al IMC layer. This problem is exacerbated after annealing, such as in high-temperature Storage (HTS). In this study, a statistical modelling approach was employed to quantitatively analyse stress, studying the evolution and characteristics of the interfacial microstructure in the thermosonic Cu wire-Al bond pad system. Microstructural analysis focused on Cu-Al IMC crystallography and compositional classification. A stress model was proposed, considering both thermal misfit and diffusion-induced stresses. Results showed that interfacial stress generally increased with higher bonding temperatures. The influence of forming gas supply was relatively minor, with oxide layers minimally impeding Cu-Al interdiffusion during Cu-Al IMC formation. This stress modelling technique hold potential as a valuable failure analysis tool for implementing Cu wire in various industries.

• Periodical: Defect and Diffusion Forum (Volume 431)
• Pages: 99-106
• DOI: https://doi.org/10.4028/p-BdLCO4
• Online since: February 2024
• Authors: Sharir Shariza*, T. Joseph Sahaya Anand
• Keywords: Cu-Al Intermetallics, Diffusion Induced Stress, Thermal Misfit, Thermosonic Wire Bonding

References

[1] Abdul Hamid, K., Badarisman, A. H., Jalar, A., Abu Bakar, M., Effects of electrolyte towards copper wire metallurgical interconnection in semiconductor, Journal of Physics: Conference Series, (2022) 2169.

DOI: 10.1088/1742-6596/2169/1/012013

[2] Wu, X., Ye, D., Zhang, H., Song, Li., Guo, L., Improvement of inter layer dielectric crack for LQFP C90FG wafer technology devices in copper wire bonding process, Microelectronics International, 39(1) (2022) 14-21.

DOI: 10.1108/mi-07-2021-0059

[3] Bogdan, G., Sobolweski, J., Bajurko, P., Yashchyshyn, Y., Oklej, J., Ostaszewski, D., A Wire-Bonded Patch Antenna for Millimeter Wave Applications, Electronics, 12(3) (2023) 632.

DOI: 10.3390/electronics12030632

[4] Wang, S., Zhang, H., Hang, C., Feng, J., Sa, Z., Li, Y., Zhang, W., Tian, Y., Phase transformation behavior of Al-Au-Cu intermetallic compounds under ultra-fast micro resistance bonding process, Materials Characterization, 180 (2021) 111401.

DOI: 10.1016/j.matchar.2021.111401

[5] Breach, C.D., Wulff, F.W., A brief review of selected aspects of the materials science of ball bonding, Microelectronics Reliability, 50(1) (2010) 1-20.

DOI: 10.1016/j.microrel.2009.08.003

[6] Du, X., Wang, W., Ding, Z., Wang, X., Qiao, Y., Wei, S., Zhu, Q., Guo, J., Effect of Cu/Ga interfacial reaction on heat transfer performance, Journal of Materials Science: Materials in Electronics, 34 (2023) 1336.

DOI: 10.1007/s10854-023-10782-3

[7] Zhou, H., Zhang, Y., Cao, J., Su, C., Li, C., Chang, A., An. B., Research Progress on Bonding Wire for Microelectronic Packaging, Micromachines, 14(2) (2023) 432.

DOI: 10.3390/mi14020432

[8] Cheng, Y.T., Verbrugge, M.W., Diffusion-Induced Stress, Interfacial Charge Transfer, and Criteria for Avoiding Crack Initiation of Electrode Particles, Journal of The Electrochemical Society, 157(4) (2010).

DOI: 10.1149/1.3298892

[9] Yarmolenko, M.V., Intermetallics disappearance rate analysis in double multiphase system, Defect and Diffusion Forum, 407 (2021) 68-86.

DOI: 10.4028/www.scientific.net/ddf.407.68

[10] Chua, K.Y., Anand, T.J.S., Shariza, S., Yong, F.K., Lee, C.C., Lim, B.H., Singh, R., Rajendra Kumar, R. T., Statistical analysis on the mechanical and micro-structural characteristics of thermosonic Cu-Al interconnection, Microelectronics Reliability, 109 (2020) 113664.

DOI: 10.1016/j.microrel.2020.113664

[11] Xiong, Y., Hu, W., Shu, Y., Luo, X., Zhang, Z., He, J., Yin, C., Zheng, K., Atomistic simulation on the generation of defects in Cu/SiC composites during cooling, Journal of Materials Science & Technology, 123 (2022) 1-12

DOI: 10.1016/j.jmst.2021.10.058

[12] Grams, A., Jaeschke, J., Wittler, O., Fabian, B., Thomas, S., Schneider-Ramelow, M., FEM-based combined degradation model of wire bond and die-attach for lifetime estimation of power electronics, Microelectronics Reliability, 111 (2020) 113683.

DOI: 10.1016/j.microrel.2020.113683

[13] Stephenson, G.B., Deformation during interdiffusion, Acta Metallurgica, 36(10) (1988) 2663-2683.

DOI: 10.1016/0001-6160(88)90114-9

[14] Pascalis, R. D., Diffusion-induced stress in a functionally graded incompressible elastic sphere, International Journal of Non-Linear Mechanics, 138 (2022)103850.

DOI: 10.1016/j.ijnonlinmec.2021.103850

[15] Zhang, N.H., Thermoelastic stresses in multilayered beams, Thin Solid Films, 515(23) (2007) 8402-8406.

DOI: 10.1016/j.tsf.2007.05.003

[16] Fuji, T., Correlation of Some Physical Properties and Chemical Composition of Solid Solution, The American Mineralogist, 45(1) (1960) 370-382.

[17] Lubarda, V.A., On the effective lattice parameter of binary alloys, Mechanics of Materials, 35(1-2) (2003) 53-68.

DOI: 10.1016/s0167-6636(02)00196-5

[18] Lubarda, V.A., Richmond, O., Second-order elastic analysis of dilute distribution of spherical inclusions, Mechanics of Materials, 31(1) (1999) 1-8.

DOI: 10.1016/s0167-6636(98)00039-8

[19] Xuan, F.Z., Shao, S.S., Wang, Z., Tu, S.T., Influence of residual stress on diffusion-induced bending in bilayered microcantilever sensors. Thin Solid Films, 518(15) (2010) 4345-4350.

DOI: 10.1016/j.tsf.2010.01.033

[20] Zhang, N.H., Chen, J.Z., An alternative model for elastic thermal stresses in two materials joined by a graded layer, Composites Part B: Engineering, 41(5) (2010) 375-379.

DOI: 10.1016/j.compositesb.2010.02.004

[21] Lee, C. C., Chua, K. Y., Tan, S. C., Effect of impact force towards Cu wire bonding reliability. In: 17th Electronics Packaging and Technology Conference, (2015).

DOI: 10.1109/eptc.2015.7412425

[22] Xu, H., Liu, C., Silberschmidt, V.V., Chen, Z., Wei, J., Sivakumar, M., Effect of bonding duration and substrate temperature in copper ball bonding on aluminium pads: A TEM study of interfacial evolution. Microelectronics Reliability, 51(1) (2011) 113-118.

DOI: 10.1016/j.microrel.2010.03.016