Sains Malaysiana 40(2)(2011): 181–190

 

Kesan Teknik Pengaktifan Bermangkin Berbeza Terhadap Prestasi Terma Penyebar Haba Cip Balikan

(Effects of Different Catalytic Activation Techniques on the Thermal Performance of Flip Chip Heat Spreader)

 

Victor Lim* & Nowshad Amin

Jabatan Kejuruteraan Elektrik, Elektronik dan Sistem, Fakulti Kejuruteraan dan Alam Bina

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E., Malaysia

 

C.S. Foong

Freescale Semiconductor, (M) Sdn. Bhd., No. 2, Jalan SS 8/2

Free Industrial Zone Sungei Way, Petaling Jaya 47300 Selangor D.E., Malaysia

 

Ibrahim Ahmad

Department of Electronics and Communication, College of Engineering

Universiti Tenaga Nasional, 43009 Kajang, Selangor D.E., Malaysia

 

Azami Zaharim

Unit Pengajian Asas Kejuruteraan, Fakulti Kejuruteraan dan Alam Bina

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E., Malaysia

 

Rozaidi Rasid & Azman Jalar

Advanced Semiconductor Packaging Laboratory

Institute of Micro Engineering and Nanoelectronics, Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor D.E., Malaysia

 

Received: 14 July 2009 / Accepted: 7 July 2010

 

 

ABSTRAK

 

Kertas ini membentangkan kesan dua teknik pengaktifan bermangkin yang berbeza terhadap prestasi terma bagi penyebar haba cip balikan. Penyaduran nikel tanpa elektrik digunakan sebagai salah satu teknik saduran kerana ia boleh membentuk satu lapisan nikel yang ketebalannya seragam ke atas substrat kuprum. Proses pengaktifan bermangkin perlu dilakukan dahulu untuk mengenapkan sesetengah atom nikel ke atas substrat kuprum, supaya enapan nikel mampu untuk memangkinkan proses penurunan yang seterusnya. Dua jenis teknik pengakitfan telah dikaji, iaitu pemulaan galvani dan penyaduran nipis nikel-kuprum. Ujian simpanan suhu tinggi telah dijalankan untuk mengkaji takat resapan antara logam bagi lapisan nikel and kuprum. Kemeresapan terma bagi penyebar haba telah dikaji dengan menggunakan peralatan Nano-flash. Keputusan yang diperolehi menunjukkan bahawa penyebar haba yang diproses dengan penyaduran nipis nikel-kuprum mempunyai nilai kemeresapan terma (35-65 mm2 s-1) yang lebih rendah berbanding dengan penyebar haba yang diproses dengan teknik pemulaan galvani (60-85 mm2 s-1). Selain daripada itu, kajian ini juga menemui ketebalan lapisan antara logam nikel-kuprum dalam penyebar haba ini bertambah daripada 0.2 μm pada keadaan asal kepada 0.55 μm selepas 168 jam simpanan suhu tinggi. Lapisan antara logam nikel-kuprum mempunyai kekonduksian terma yang lebih rendah berbanding dengan kuprum tulen, ini telah merendahkan kemeresapan terma bagi penyebar haba. Kesimpulannya, teknik pemulaan galvani meyediakan prestasi terma yang lebih baik untuk penyebar haba yang digunakan dalam pembungkusan semikonduktor.

 

Kata kunci: Pemulaan galvani; penyaduran nikel tanpa elektrik; penyaduran nipis nikel-kuprum; penyebar haba

 

ABSTRACT

 

This paper presents the effects of two different catalytic activation techniques on the thermal performance of flip chip heat spreaders. Electroless nickel plating is used as a plating technique as it can form a uniform thickness of nickel layer onto the copper substrate. Catalytic activation process needs to be done first to deposit some nickel atom onto copper substrate, so that the deposited nickel is able to catalyze the following reduction process. The two activation techniques investigated are galvanic initiation and thin nickel-copper strike. High temperature storage tests were ran to investigate the extent of intermetallic diffusion between the nickel and copper layers. Thermal diffusivity of these heat spreaders was studied using the Nano-flash apparatus. The results obtained showed that heat spreaders processed with thin nickel copper strike have lower thermal diffusivities (35-65 mm2 s-1) compared to those heat spreaders processed with galvanic-initiation (60-85 mm2 s-1). It is also discovered that the nickel-copper intermetallic layers of these heat spreaders grew thicker from 0.2 μm at initial time until 0.55 μm after high temperature storage of 168 hours. Nickel-copper intermetallic layers have lower thermal conductivity compared to pure copper, this further degrading the thermal diffusivity of these heat spreaders. As a conclusion, the galvanic initiation technique provides better thermal performance for heat spreaders used in semiconductor package.

 

Keyword: Electroless nickel plating; galvanic initiation; heat spreader; thin nickel-copper strike

 

REFERENCES

 

Aschenbrenner, R., Ostmann, A., Beutler, U., Simon, J. & Reichl, H. 1995. Electroless nickel/copper plating as a new bump metallization. IEEE Transaction on Components, Packaging, and Manufacturing Technology-Part B 18(2): 334-338.

Bakonyi, I., Toth-Kadar, E., Toth, J., Becsei, T., Tarnoczi, T. & Kamasa, P. 1999. Magnetic and electrical transport properties of electrodeposited Ni–Cu alloys and Ni81Cu19/Cu multilayers. J. Phys.: Condens. Matter 11: 963-973.

Cengel, Y.A. 2007. Heat and Mass Transfer: A Practical Approach. 3rd Ed. Boston: McGraw-Hill.

Chen, Yujin, Cao, Maosheng, Xu, Qiang & Zhu, Jing. 2003. Electroless nickel plating on silicon carbide nanoparticles. Surface and Coating Technology 172: 90-94.

Cui, Guofeng, Li, Ning, Li, Deyu & Chi, Minglei. 2005. Study of optimized complexing agent for low-phosphorus electroless nickel plating bath. Journal of the Electrochemical Society 152(10): C669-C674.

Fritz, T., Mokwa, W. & Schnokenberg, U. 2001. Material characterization of electroplated nickel structures for microsystem technology. Electrochimica 47: 55-60.

Gaal, P.S., Thermitus, M.A. & Stroe, D.E. 2004. Thermal conductivity measurements using the flash methold. Journal of Thermal Analysis and Calorimetry 78: 185-189.

JEDEC. 2004. JESD22-A103C: High Temperature Storage Life. Arlington: JEDEC Solid State Technology Association.

Kanungo, J., Pramanik, C., Bandopadhyay, S., Gangopadhyay, U., Das, L., Saha, H. & Gettens, R.T.T. 2006. Improved contacts on a porous silicon layer by electroless nickel plating and copper thickening. Semicond. Sci. Technol. 21: 964-970.

Kwon, Y.S., An, V.V., Ilyin, A.P. & Tikhonov, D.V. 2006. Properties of powders produced by electrical explosions of copper-nickel alloys wires. Materials Letters 61: 3247-3250.

Rao, G.R., Mishra, B.G. & Sahu, H.R. 2004. Synthesis of CuO, Cu and CuNi alloy particles by solution combustion using carbahydrazide and N-tertiarybutoxy¬carbonylpiperazine fuels. Materials Letters 58: 3523-3527.

Saitou, M., Okudaira, Y. & Oshikawa, W. 2003. Amorphous structures and kinetics of phosphorous incorporation in electrodeposited Ni-P thin films. Journal of the Electrochemical Society 150(3): C140-C143.

Samson, E.C., Machiroutu, S.V., Chang, J.Y., Santos, I., Hermerding, J., Dani, A., Prasher, R. & Song, D.W. 2005. Interface material selection and thermal management technique in second-generation platforms built on Intel Centrino mobile technology. Intel Technology Journal 9(1): 75-86.

Sartorelli, M.L., Schervenski, A.Q., Delatorre, R.G., Klauss, P., Maliska, A.M. & Pasa, A.A. 2001. Cu–Ni thin films electrodeposited on Si: composition and current efficiency. Phys. Stat. Sol. (a) 187(1): 91-95.

Singh, S., Ghosh, S.K., Basu, S., Gupta, M., Mishra, P. & Groverb, A.K. 2006. Structural and magnetic study of an electrodeposited Ni/Cu thin film by neutron reflectometry. Electrochemical and Solid-State Letters 9(3): J5-J8.

Watanabe, H. & Honma, H. 1998. Direct electroless nickel plating on copper circuits using DMAB as a second reducing agent. IEMT/IMC Proceedings: 149-53.

Yamada, T., Yamamoto, A., Fujiwara, M. & Kunigi, Y. 1993. Strength evaluation and effect of graphite on strength of electroless nickel plating on cast iron. Journal of Materials Science 28: 3513-3518.

 

*Corresponding author: email: victorlimch@hotmail.com