Polishing pad surface characterisation in chemical mechanical planarisation

McGrath, John; Davis, Chris

doi:10.1016/j.jmatprotec.2004.04.094

Cited by 115 publications

(80 citation statements)

References 14 publications

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“…It is known that the pad surface features * Corresponding author. deform during the polishing and as a result the polishing ability of the pad is dramatically reduced without the conditioning process [2,3].…”

Section: Introductionmentioning

confidence: 99%

Effects of pad properties on material removal in chemical mechanical polishing

Park

Kim

Chang

et al. 2007

Journal of Materials Processing Technology

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Section: Introductionmentioning

confidence: 99%

Effects of pad properties on material removal in chemical mechanical polishing

Park

Kim

Chang

et al. 2007

Journal of Materials Processing Technology

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“…For example, the pad can become much more hydrophobic due to the glazing effect (fused polymeric asperities) during the polishing. A pad conditioning step will bring the level of hydrophilicity back to the original level [27,39]. In reality, such a steady state may never be reached as the pad continues to react with the chemicals in the slurry throughout the polishing process.…”

Section: Pad Conditioning and Its Effect On Cmp Performancementioning

confidence: 99%

“…The corrosion may lead to a shedding of diamond particles and corroded debris. These large and hard particles can clog the pores on the pad and will cause severe scratches [27,39]. The loss of diamond particles also decreases the conditioning efficiency and polishing performance.…”

Section: Pad Conditioning and Its Effect On Cmp Performancementioning

confidence: 99%

Pads for IC CMP

Wang

Paul

Kobayashi

et al. 2007

Microelectronic Applications of Chemical Mechanical Planarization

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The chemical-mechanical polishing or planarization (CMP) process is a complex interplay between the wafer and the consumables involved. The consumables include slurry, pad, conditioner, and so on. During polishing, the pad carries the slurry and delivers it to the wafer surface. It also transmits the normal and shear forces from the polisher to the wafer. Therefore, polishing pad plays a critical role in the CMP process and influences the outcomes such as material removal rate (MRR), within-wafer nonuniformity (WIWNU), wafer-to-wafer nonuniformity (WTWNU), step height reduction efficiency (SHRE), and defect counts.As the CMP process is a combination of mechanical and chemical processes, the polishing pad has to endure repeated mechanical stress and constant chemical attacks. The applied downforce and polishing-induced friction force cause various levels of compression and abrasion. Slurry components such as oxidizers and acids can react with different components of the pads. Thus the polishing pad must have sufficient mechanical integrity and chemical resistance to survive the rigors of polishing. Polishing pads must balance the needs of hardness, modulus for planarity, and strength to resist wear and tear during polishing. Pads must also be able to survive the aggressive slurry chemistry used in CMP polishing without degrading, delaminating, blistering, or warping, since CMP slurries for the polishing of interlevel dielectric (ILD) oxide layers are usually highly alkaline with pH as high as 11, and CMP slurries for the polishing of metal films are highly acidic Microelectronic Applications of Chemical Mechanical Planarization, Edited by Yuzhuo Li

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“…During CMP process, the wafer is pressed face down against a rotating polishing pad and slurry is injected onto the polishing pad surface. However, a newly installed polishing pad has to be sufficiently broken-in in order to achieve a consistent material removal rate from wafer-to-wafer [1]. During pad break-in, ultra-pure water (UPW) is injected onto the pad surface and a diamond conditioning disc is employed to make the pad surface reach a desired surface micro-texture (i.e.…”

Section: Introductionmentioning

confidence: 99%

Feasibility of a Real-Time Method in Determine the Extent of Pad Break-In During Copper Chemical Mechanical Planarization

2016

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Material removal rate, shear force and variance of shear force during copper polishing are studied as a function of pad break-in time. Results show that copper removal rate and variance of shear force increase within 30 min of pad break-in. Spectral analysis of raw shear force data is employed to help elucidate the fundamental physical phenomena during copper chemical mechanical planarization. Fast Fourier transform is performed to convert the shear force data from time domain to frequency domain. The energy distribution of copper polishing is quantified which sheds light on the effect of pad break-in time. Spectral analysis indicates that as pad break-in progresses, newly formed pad asperities dominate the interaction with the wafer and therefore shifting the spectral amplitudes to the higher frequency peaks (i.e. 101-108 Hz). Further spectral analysis also confirms that such increases in the high-frequency range dominate the distribution of energies. This study shows that a combination of unique spectral fingerprinting and analysis of force variance can be used to monitor the progress of pad break-in in real-time. This work underscores the importance of real-time detection and non-destructive method in chemical mechanical planarization process to quantify the extent of pad break-in.

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Polishing pad surface characterisation in chemical mechanical planarisation

Cited by 115 publications

References 14 publications

Effects of pad properties on material removal in chemical mechanical polishing

Effects of pad properties on material removal in chemical mechanical polishing

Pads for IC CMP

Feasibility of a Real-Time Method in Determine the Extent of Pad Break-In During Copper Chemical Mechanical Planarization

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