Effects of moisture and temperature ageing on reliability of interfacial adhesion with black copper oxide substrate

• Published in: Journal of adhesion science and technology Vol. 19; no. 6; pp. 427 - 444
• Main Authors: Kim, Jang-Kyo, Lebbai, Mohamed, Lam, Yiu Ming, Hung, Pamela Y. P., Woo, Ricky S. C.
• Format: Journal Article
• Language: English
• Published: Leiden Taylor & Francis Group 01.01.2005; Brill
• Subjects: Applied sciences; BLACK OXIDE COATING; COPPER SUBSTRATE; Design. Technologies. Operation analysis. Testing; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Exact sciences and technology; HYGROTHERMAL AGEING; Integrated circuits; INTERFACIAL ADHESION; MOISTURE ADSORPTION; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Polyimide; hygrothermal ageing; Adhesivity; Thermal ageing; Epoxy resin; Plastic packaging; Experimental study; BGA technology; Surface treatment; moisture adsorption; Interface properties; black oxide coating; Humidity effect; interfacial adhesion; Electronic packaging; Adhesive joint; Integrated circuit; Surface properties; Artificial ageing; Copper oxide; Copper substrate; Adhesive; Fracture mode
• DOI: 10.1163/1568561054352568
• ISSN: 0169-4243

The reliability of adhesion performance of bare Cu, as-deposited and surface-hardened black oxide coatings on Cu substrates was studied. The interfacial adhesion with a polyimide adhesive tape and an epoxy moulding compound was measured using the button shear and tape peel tests after hygrothermal ageing in an autoclave, high temperature ageing and thermal cycles. Moisture adsorption and desorption studies at different aging times suggested that the black oxide coating was effective in reducing the moisture adsorption. The bond strengths for all substrates remained almost unchanged after thermal ageing at 150°C for 8 h. Thermal cycling between −50°C and 150°C for 500 cycles reduced by about 20% the button shear strength of the as-deposited black oxide substrate, but it did change much the bonding performance of the bare Cu substrate. Hygrothermal ageing at 121°C/100% RH in an autoclave was most detrimental to adhesion performance because of the combined effect of elevated temperature and high humidity. The reduction in button shear strength after the initial ageing for 48 h was 50-67%, depending on the type of coating. In all accelerated ageing tests, the residual interfacial bond strengths were consistently much higher for the black-oxide-coated substrates than the bare Cu surface, confirming a higher reliability of black oxide coating. Fracture surfaces analysis of tape-peeled bare copper substrates after 500 cycles of thermal loading revealed a transition in failure mechanism from interfacial to cohesive failure. In contrast, the failure mechanism remained unchanged for black-oxide-coated substrates. The observations made from the button shear and tape peel tests were generally different because of the different fracture modes involved.