Copper ball bond shear test for two pad aluminum thicknesses

Andrews, Derek; Hill, Levi; Collins, A. A.; Hoo, Kok Inn; Hunter, Stevan

doi:10.1109/eptc.2014.7028415

“…The ball shear force is a measurement of the bond adhesive strength using a destructive test, as shown in Figure 6, in which a shear tool is applied in the lateral direction until the ball separates from the pad. The measured peak force causing the separation was the ball shear force (in grams) (Andrews et al, 2014;Manoharan et al, 2017;Manoharana et al, 2018). The ball size and thickness are the diameter and height of the bond ball, respectively, as shown in Figure 7.…”

Section: Methodsmentioning

confidence: 99%

Multi-response optimization of IC wire bonding for large probe marks by the RSM and desirability function approach

Chiu

¹

,

Wang

²

,

Lu

³

2022

Int J Adv Manuf Technol

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Wire bonding is key to high-quality IC assembly in semiconductor packaging. An electrical test was conducted before wire bonding. During the electrical test, the needle probes touched the surface of each bond pad resulting in a probe trace left, called probe marks. The probe mark on the bond pad affects the adhesion between the bond pad and copper ball. Generally, the bond ball can be removed easily under shear testing if the ratio of probe mark area to pad area is greater than 20%. A large probe mark causes a defect in the yield. However, rejecting the orders of wafer batches with large probe marks will result in a loss of market share and good relationships with clients. In order to find the optimal parameter settings for the batches of chips with probe mark areas larger than 20% and deal with multiple response problems, this study aims to optimize the parameters of operation for the IC with large probe marks in the wire bonding process to improve process capability and production yield. Response surface methodology (RSM) optimization with the desirability function approach was introduced into the central composite design to obtain the optimal process parameters efficiently and eliminate defects. The optimal parameter settings for the four factors were determined as follows: 90 mA bond power, 12 ms bond time, 10 g bond force, and 180 °C bond temperature. The validation testing confirms that optimal parameter settings increase yield from 98.84% to 99.94% with good process capability, helping companies improve quality, reduce defect costs, and improve customer relationships.

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“…The surge of introduction of Cu wire to replace Au wire due to high Au price [6] has leaded to new sets of bonding metallurgy and process issues. The effects are pre-mature failures and higher production yield losses [7][8][9][10][11]. Adversely, Cu wire brings along molding advantage of resistant to wire sweep due to its higher modulus.…”

Section: Introductionmentioning

confidence: 99%

Perfect Molding Challenges and The Limitations “A Case Study”

Tatt¹,

Huat²,

Tarmizi³

et al. 2018

Adv. sci. technol. eng. syst. j.

1

0

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Driven by today's market demand, semiconductor is pushing towards the zero-defect direction. The improvement demanded in semiconductor manufacturing is becoming increasingly challenging. In this paper, common molding defects comprise of voids, incomplete fills, and piping holes are studied systematically, focusing on three key areas: 1) Potential mold flow weakness; 2) Molding temperature stability; as well as 3) Defined pressure effects. The in-depth understanding of mold flow in the LF design is achieved via mold flow numerical tool. The numerical model prediction is verified by short shots and end-of-line auto vision data. Advance Process Control (APC) is adopted to measure the stability of key molding parameters like temperature, transfer profile and pressure. The mechanism of transferring the compound in relation to pressure is also analyzed and its effect to molding quality is also assessed. A methodical approach is utilized to understand the process and equipment built-in capabilities from two different equipment manufacturers. The real time transfer profile monitoring is activated for diagnosis of the system issue which leads to the finding of design error of a critical component. The dual temperature controller on one of the systems is analyzed to stabilize temperature for improved compound flow-viscosity control. The process limitations are assessed and transfer profiles are optimized to modify the melt front. By shifting the molding defects to non-critical location, the formation of void at the 500um diameter bonded wire loop peak will be avoided. The verification of potential negative impacts resulted from changes to improve voids, incomplete fills and piping holes are also included in this study. Up-front analysis by adopting numerical tool as a means of understanding the existing design and identifying improvement approach are proven to be useful.

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Multi-response Optimization of IC Wire Bonding for Large Probe Marks by the RSM and Desirability Function Approach

Chiu

¹

,

Wang

²

,

Lu

³

2022

Preprint

0

View full text Add to dashboard Cite

Wire bonding is key to high-quality IC assembly in semiconductor packaging. An electrical test was conducted before wire bonding. During the electrical test, the needle probes touched the surface of each bond pad resulting in a probe trace left, called probe marks. The probe mark on the bond pad affects the adhesion between the bond pad and copper ball. Generally, the bond ball can be removed easily under shear testing if the ratio of probe mark area to pad area is greater than 20%. A large probe mark causes a defect in the yield. However, rejecting the orders of wafer batches with large probe marks will result in a loss of market share and good relationships with clients. In order to find the optimal parameter settings for the batches of chips with probe mark areas larger than 20% and deal with multiple response problems, this study aims to optimize the parameters of operation for the IC with large probe marks in the wire bonding process to improve process capability and production yield. Response surface methodology (RSM) optimization with the desirability function approach was introduced into the central composite design to obtain the optimal process parameters efficiently and eliminate defects. The optimal parameter settings for the four factors were determined as follows: 90 mA bond power, 12 ms bond time, 10 g bond force, and 180 °C bond temperature. The validation testing confirms that optimal parameter settings increase yield from 98.84% to 99.94% with good process capability, helping companies improve quality, reduce defect costs, and improve customer relationships.

show abstract

Copper ball bond shear test for two pad aluminum thicknesses

Cited by 3 publications

References 3 publications

Multi-response optimization of IC wire bonding for large probe marks by the RSM and desirability function approach

Multi-response optimization of IC wire bonding for large probe marks by the RSM and desirability function approach

Perfect Molding Challenges and The Limitations “A Case Study”

Multi-response Optimization of IC Wire Bonding for Large Probe Marks by the RSM and Desirability Function Approach

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