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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
Diserahkan:
14 Julai 2009 / Diterima: 7 Julai 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
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*Pengarang untuk surat-menyurat: email: victorlimch@hotmail.com
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