关键词: 铜引线键合, 金属间化合物, 冲击力, 成形力, 摩擦力, 键合力

Abstract: In recent years, in semiconductor integrated circuit packaging process, gold wire is gradually replaced by copper wire, in order to obtain lower manufacturing cost, better electrical/thermal performance and higher product reliability. However, due to the copper wire than gold compared with high hardness and easy oxidation, the wire bonding process between Cu-Al intermetallic compounds are not as high in density and coverage as the traditional Au-Al intermetallic compound, at the same time easy to cause mechanical damage and loose to the circuit under the bonding pad. Low coverage of intermetallic compounds can influence on the resistant properties to chloride corrosion and product reliability, so how to optimize bonding copper wire technology to improve the Cu-Al intermetallic compounds between density and coverage becomes very important. In this paper, the formation mechanism, phase distribution and density of Cu-Al intermetallic compounds are systematically studied by means of SEM, XRD and other experimental instruments, 3D elastic-plastic coupled finite element analysis, experimental design and other research methods. The bonding process was subdivided into four stages: impact, deforming, scrub and bonding. The interaction mechanism and key influencing parameters of the Cu-Al intermetallic compounds in each stage were analyzed by finite element method and verified by experiment. Finally, a robust and practical copper wire bonding process window is established to realize Cu-Al intermetallic compounds with high coverage and density. The analytical methods adopted during this period also provide theoretical and practical guidance for the optimization of other semiconductor chip bonding process parameters.

Key words: Cuwirebonding, intermetalliccompounds, impactforce, deformingforce, scrubforce, bondingforce