Sains Malaysiana 43(6)(2014): 827–832

Dimensional and Structural Stability of Gamma Irradiated Stacked Die Quad Flat No Leads (QFN)

(Kestabilan Dimensi dan Struktur Dai Bertingkat Tanpa Kaki (QFN) Tersinar Gamma)

SIEW PENG FOO, WAN YUSMAWATI WAN YUSOFF & AZMAN JALAR*

Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia

Received: 18 March 2013/Accepted: 12 September 2013

ABSTRACT

The physical properties and structural stability of the Quad Flat No-Leads (QFN) package with different gamma radiation doses have been investigated. The packages were irradiated with Co-60 gamma radiation with varying doses of 5 Gy, 50 Gy, 500 Gy, 5 kGy and 50 kGy with operating dose of 2.54 kGy/h at room temperature. The infinite focus microscope (IFM) was used to measure the dimensional change and slanting/warpage behaviour, while the 3D CT Scan X-ray machine was used to determine the occurrence of deflection on a wire in package due to exposure. It is believed that radiation effect on ceramic filler in the epoxy mold compound (EMC) plays an important role to induce the defects and resulted in swelling of the package. The slanting/warpage behaviour is believed to be caused by the swelling behaviour of ceramic filler and further induced structural stability. The induced stress on the EMC structural after the dimensional change and slanting/warpage failure leads to the occurrence of wire sweep. The finding suggests that defect production in swelled ceramic filler leads to the occurrence of dimensional and structure instability.

Keywords: Dimensional change; gamma radiation; QFN; structure stability

ABSTRAK

Kestabilan sifat fizikal dan struktur pakej cip tanpa kaki (QFN) dengan dos sinar gama yang berbeza telah dikaji. Pakej diradiasikan dengan sinaran Co-60 gama dengan pelbagai dos 5 Gy, 50 Gy, 500 Gy, 5 kGy, dan 50 kGy serta dos operasi 2.54 kGy/jam pada suhu bilik. Mikroskop fokus infinit (IFM) telah digunakan untuk mengukur perubahan dimensi dan kelakuan serong/keledingan, manakala mesin 3D CT sinar x telah digunakan untuk menentukan berlakunya pesongan pada wayar di dalam pakej disebabkan oleh pendedahan. Dipercayai bahawa kesan sinaran pada pengisi seramik dalam acuan sebatian epoksi (EMC) memainkan peranan yang penting dalam mendorong kecacatan dan menyebabkan pembengkakan pakej. Kelakuan serong/keledingan dipercayai disebabkan oleh kelakuan pembengkakan pengisi seramik dan seterusnya mendorong ketidakstabilan struktur. Aruhan tegasan pada struktur EMC selepas perubahan dimensi dan kegagalan serong/keledingan membawa kepada berlakunya pesongan wayar. Penemuan ini menunjukkan bahawa penghasilan kecacatan dalam pembengkakan pengisi seramik membawa kepada berlakunya dimensi dan struktur tidak stabil.

Kata kunci: Kestabilan struktur; perubahan dimensi; QFN; sinar gama

REFERENCES

Abdullah, S., Aziz, Z.A., Ahmad, I., Jalar, A. & Abdullah, M.F. 2008. Wire sweep issue in a newly developed quad flat no-lead (QFN) semiconductor package. 7th WSEAS International Conference on Microelectronics, Nanoelectronics, Optoelectronics (MINO). pp. 40-44.

Ahmad, I., Bachok, N.N., Chiang, N.C., Talib, M.Z.M., Rosle, M.F., Latip, F.L.A. & Aziz, Z.A. 2007. Evaluation of different die attach film and epoxy pastes for stacked die QFN package. IEEE 9th Electronic Packaging Technology Conference. pp. 869-873.

Ardebili, H. & Pecht, M.G. 2009. Chapter 2 plastic encapsulant materials. In Encapsulation Technologies for Electronic Applications. A Volume in Materials and Processes for Electronic Applications, edited by Ardebili, H. & Pecht, M.G. USA: Elsevier Inc. pp. 47-127.

Chmielewski, M. & Weglewski, W. 2013. Comparison of experimental and modelling results of thermal properties in Cu-AlN composite materials. Buletin of the Polish Academy of Sciences: Technical Sciences 61(2): 507-514.832

Chung. D.D.L. 1995. Low thermal expansion composite materials for electronic packaging. In Materials for Electronic Packaging, edited by Deborah, D.L.C. USA: Butterworth- Heinemann. pp. 145-146.

Gao, F., Weber, W.J. & Devanathan, R. 2002. Defect production, multiple ion–solid interactions and amorphization in SiC. Nuclear Instruments and Methods in Physics Research 191: 487-496.

Huang, C.Y. & Lin, Y.H. 2013. Applying CHAID algorithm to investigation the critical attributes of void formation in QFN assembly. Soldering & Surface Mount Technology 25(2): 117-127.

Hughes, A.E. & Pooley, D. 1975. Interaction of solids with high energy radiation. In Real Solids and Radiation, edited by Mott, S.N. & Noakes, G.R. London: Wykeham Publications. pp. 98-105.

Iseki, T., Tezuka, M., Kim, C.S., Suzuki, T., Suematsu, H. & Yano, T. 1993. Hardening by point defects in neutron irradiated AlN and SiC. Journal of Nuclear Science and Technology 30(1): 68-77.

Kang, H.K. & Kang, S.B. 2006. Thermal decomposition of silicon carbide in a plasma-sprayed Cu/SiC composite deposit. Materials Science and Engineering A 428(1-2): 336-345.

Kinoshita, C. 2007. Microstructural evolution of irradiated ceramics. In Radiation Effects in Solids, edited by Sickafus, K.E., Kotomin, E.A. & Uberuaga, B.P. Netherlands: Springer. pp. 193-232.

Komori, S. & Sakamoto, Y. 2009. Development trend of epoxy molding compound for encapsulating semiconductor chips. In Materials for Advanced Packaging, edited by Lu, D. & Wong, C.P. LLC: Springer. pp. 339-363.

Lemaignan, C. 2010. Nuclear materials and irradiation effects. In Handbook of Nuclear Engineering, edited by Cacuci, D.G. US: Springer. pg. 544-641.

Rao, P.R., Wang, X. & Theuwissen, A.J.P. 2008. Degradation of CMOS image sensors in deep-submicron technology due to γ-irradiation. Solid-State Electronics 52: 1407-1413.

Weber, W.J., Ewing, R.C., Catlow, C.R.A., Diaz de la Rubia, T., Hobbs, L.W., Kinoshita, C., Matzke, H.J., Motte, A.T., Nastasi, M., Salje, E.K.H., Vance, E.R. & Zinkle, S.J. 1998. Radiation effects in crystalline ceramics for the immobilization of high-level nuclear waste and plutonium. Journal of Materials Research 3(6): 1434-1484.

Yusoff, W.Y.W., Jalar, A., Othman, N.K. & Rahman, I.A. 2011. Effect of gamma-irradiation towards stress-strain curve of single die QFN package. Material Science Forum (694): 620-624.

Zinkle, S.J. & Kinoshita, C. 1997. Defect production in ceramics. Journal of Nuclear Materials 251: 200-217.

*Corresponding author; email: azmn@ukm.edu.my