Effects of commercial no-clean flux on reliability of fine pitch flip-chip package with solder bumps and copper pillars

Wakeel, Saif and Haseeb, A. S. Md. Abdul and Hoon, Khoo Ly and Amalina, Muhammad Afifi (2022) Effects of commercial no-clean flux on reliability of fine pitch flip-chip package with solder bumps and copper pillars. IEEE Transactions on Components Packaging and Manufacturing Technology, 12 (8). pp. 1386-1394. ISSN 2156-3950, DOI https://doi.org/10.1109/TCPMT.2022.3191604.

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In this work, two commercial no clean fluxes, namely, extremely low residue no-clean flux (NCF) (NC-1) and ordinary NCF (NC-2), were used for the preparation of a fine pitch flip-chip package with a 7.6 x 7.6 mm(2) Si die on a 17 x 17 mm(2) organic substrate. One water-soluble (WS) flux was also used for comparison. Moisture sensitivity of the package was evaluated using JESD22-A113D (30 degrees C/60% relative humidity (RH), 192 h, 3x reflow at 260 degrees C). Thermal cycling tests were performed following JESD22-A104D (-65 degrees C to 150 degrees C). The high-temperature storage life (HTSL) of the packages was investigated using JESD22-A103C (175 degrees C). Underfill delamination or voids in the package were investigated by confocal scanning acoustic microscopy (C-SAM). Failure characteristics of the packages were also studied using scanning electron microscopy (SEM). After moisture sensitivity level (MSL) test, vehicles prepared by NC-1 and NC-2 showed failure. SEM images revealed severe delamination between underfill and solder mask in the presence of amine/amide and carboxylic acid-based NCF residue. Solder bump crack were found at <500 cycles for samples prepared with NC-1 which contains tertiary amine and long carbon chain (C8:C10:C12) carboxylic acid-based. However, failure occurred at <1500 cycles for NC-2 containing secondary amide and shorter carbon chain length (C3) carboxylic acid. Samples prepared using WS did not show any failure for up to 2000 cycles. Thus, NCF-treated assemblies performed poorly in moisture sensitivity and temperature cycling tests.

Item Type: Article
Uncontrolled Keywords: High temperature storage life (HTSL); Moisture sensitivity; No-clean flux (NCF); Reliability analysis; Thermal cycling; Underfill delamination
Subjects: T Technology > TS Manufactures
Divisions: Faculty of Engineering
Depositing User: Ms. Juhaida Abd Rahim
Date Deposited: 21 Sep 2023 08:44
Last Modified: 21 Sep 2023 08:45
URI: http://eprints.um.edu.my/id/eprint/41404

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