Effect of chromium-gold and titanium-titanium nitride-platinum-gold metallization on wire/ribbon bondability

Gold metallization on wafer substrates for wire/ribbon bond applications require good bond strength to the substrate without weakening the wire/ribbon. This paper compares the ribbon bondability of Cr/Au and Ti/TiN/Pt/Au metallization systems. Both chromium and titanium are used to promote adhesion...

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Bibliographic Details
Main Authors: Jianbiao Pan, Pafchek, R.M., Judd, F.F., Baxter, J.
Format: Conference Proceeding
Language:English
Subjects:
Annealing
Applied sciences
Chromium
Degradation
Design. Technologies. Operation analysis. Testing
Electronics
Exact sciences and technology
Gold
Integrated circuits
Metallization
Microelectronic fabrication (materials and surfaces technology)
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
Sputter etching
Tin
Titanium
Wafer bonding
Wire
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Summary:Gold metallization on wafer substrates for wire/ribbon bond applications require good bond strength to the substrate without weakening the wire/ribbon. This paper compares the ribbon bondability of Cr/Au and Ti/TiN/Pt/Au metallization systems. Both chromium and titanium are used to promote adhesion between substrates and sputtered gold films. Both can diffuse the gold surface after annealing and degrade the wire/ribbon bondability. Restoring bondability by ceric ammonium nitrate (CAN) etch was investigated. Experiments were conducted to investigate the effect of Cr/Au and Ti/TiN/Pt/Au, annealing, and CAN etch processes on 25.4 times; 254 /spl mu/m (1 /spl times/ 10 mil) ribbon bonding. All bonds were evaluated by noting pull strengths and examining specific failure modes. The results show that there is no significant difference in bondability between Cr/Au and Ti/TiN/Pt/Au before the annealing process. At this point excellent bond strength can be achieved. However, wire/ribbon bondability of Cr/Au degraded after the wafers are annealed. The experimental results show that a CAN etch can remove Cr oxide. Improvement of wire/ribbon bondability of Cr/Au depends on the CAN etch time. The annealing process does not have significant effect on bondability of Ti/TiN/Pt/Au metallization. Auger electron spectroscopy was used to investigate what caused the difference in bondability between the two metallization.
ISSN:1089-8190
2576-9626
DOI:10.1109/IEMT.2004.1321657