Fine pitch probing and wirebonding and reliability of aluminum capped copper bond pads

Tran, Tu Anh; Yong, Lois; Williams, B.; Chen, S.; Chen, A.

doi:10.1109/ectc.2000.853444

Cited by 37 publications

(14 citation statements)

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“…This study aims to identify and optimize wire bonding process in order to get robust, reliable wire bond process. [2] II. Challenges to assembly process Wire bonding is the most widely used first-level interconnection technology between chip and package terminals.…”

Section: Introductionmentioning

confidence: 98%

Low K CMOS90 2N gold wire bonding process development

Han¹,

Yan²

2009

2009 International Conference on Electronic Packaging Technology &Amp; High Density Packaging

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The electronics industry is mainly driven by the demand for smaller, faster, higher complexity, more reliable and cheaper device. Reduction in bond pad patch and low K wafer were introduced into mass production for miniaturation and signal transmission integrity. High safety requirement and longer working life demand high reliability performance especially in automotive and aerospace filed. Although trends in electronic packing have been focused on the development of flip chip, Wire bonding still cements its position in chip interconnection technology. In IC assembly, gold wire is the key material in wire bonding process to connect chip to substrate. 2N gold wire with specific dopant is applied in many types of package for stringent reliability requirement field. This study will focus on 2N gold wire application in wire bonding process.Bonding wire, bonding capillary, and wire bonding parameters, was selected as critical factors in this study. This paper describes the key 1st bond parameter optimization on CMOS90 low K device. Gold wire and capillary design were studied. Tail scrubs function of KNS maxum plus wire bonder was also studied to find out how to produce robust 2nd bond. The Newly-designed capillary from SPT aimed to improve wire stitch pull strength was also studied to improve 2N gold wire 2nd bond stitch bond which have weak stitch bond strength result from its big hardness. Critical responses such as Ball size, Ball height bonded ball diameter ratio, bonded ball placement, wire pull strength, ball shear strength, and stitch pull strength were studied to understand the wire bonding effect of low k device. DOE (Design of Experiment) and RSM (response surface methodology) was used to optimize the wire bond process. Thermal aging test coupled with wire pull and ball shear test with recording failure mode were studied. The IMC (Inter Metallic Coverage) of the Au-Al and cratering were also tested.The combination of the low K material and harder 2N wire introduction leaves a narrow process window for packaging assembly, and raises challenges to wire bonding process in terms of process manufacturability. The studies showed that 2N wire were found to be a good replacement of traditional 3N wires on improving bonding integrity of the low K device. Capillary geometry design is also critical to achieve a better IMC coverage, robust 2nd bond. The newly-designed capillary from SPT aimed to improve 2N wire stitch pull strength.

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Section: Introductionmentioning

confidence: 98%

Low K CMOS90 2N gold wire bonding process development

Han¹,

Yan²

2009

2009 International Conference on Electronic Packaging Technology &Amp; High Density Packaging

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“…However, with this strategy, issues still persist, including the high cost of the added lithography and metallization steps for these layers. Because copper readily diffuses into aluminum creating unreliable intermetallics, a barrier metal such as Ta, Ti, or TiN is required between the copper and aluminum to prevent electromigration [6].…”

Section: Introductionmentioning

confidence: 99%

High temperature performance study of gold wire bonding on a palladium bonding pad

Sasangka

Tan²

2006

2006 8th Electronics Packaging Technology Conference

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Translating technology from aluminum based to copper based semiconductor has unique issues especially in wire bonding reliability. Copper is very easy to be oxidized when exposed to the air. Palladium was added to cover copper in order to resolve this problem. Finally, the gold wire is bonded with Palladium instead of Copper.The performance (mechanical and strength) of this Interconnection between gold wire and palladium pad prior to High Temperature Storage was investigated. Failure and Micro analysis were carried out through a series of applications of analytical tools including SEM, EDX, FIB, and BIT. Result of the observation showed that the interconnection of Au/Pd was very good. Intermetallic compound was not found and impurities in molding compound also did not have significant impact on the reliability.Migration profile of elements in bond pad was analyzed using X-Ray Photoelectron Spectroscopy. Diffusion of Gold into Palladium and migration of copper over the Palladium were observed. On the other hand, Nickel and Palladium were deduced as stable elements. There was no significant migration of these two elements. Overall, migration phenomena of these elements did not affect significantly to the reliability of gold wire/Pd pads..

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“…Based on diffusion theories and the effect of thermal and kinetic energies on the behavior of materials, Pham and Huth [2] proposed a model for a robust bond. Tran et al [3] conducted wirebonding experiments to measure contact resistance and to perform reliability assessment. Using propriety transmission laser vibrometer, Tamura et al [4] developed a calibration system that enables the real time acquisition of vibration characteristics of the capillary.…”

Section: Introductionmentioning

confidence: 99%