Effect of Pad Surface Micro-Texture on Removal Rate during Interlayer Dielectric Chemical Mechanical Planarization Process

Liao, Xiaoxin; Zhuang, Yun; Borucki, L.; Cheng, Jun; Theng, Siannie; Ashizawa, Toranosuke; Philipossian, Ara

doi:10.7567/jjap.52.018001

Cited by 17 publications

(22 citation statements)

References 18 publications

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“…(6) Separately, Liao et al found that a pad conditioned at a higher downforce resulted in a higher oxide removal rate due to a dramatic decrease in pad surface contact area, therefore an increase in local contact pressure. (11) These studies provide evidence that the magnitude of conditioning downforce can cause different outcomes to the pad surface microtexture. As such, there is a need to further investigate the relationship between conditioning downforce and its effect on the micro-texture during oxide CMP.…”

Section: Introductionmentioning

confidence: 92%

Effect of Conditioning Downforce and Pad Break-In Time on Pad Surface Micro-Texture

McAllister

Stuffle

Sampurno

et al. 2018

ECS J. Solid State Sci. Technol.

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The effect of conditioning downforce during pad break-in, and its impact on the evolution of pad surface micro-texture was investigated. Two different conditioning downforces were used to break-in pads. Pad samples were extracted after certain break-in times and analyzed for their topography and contact area using confocal microscopy. Results showed that the pad-wafer contact area and contact density decreased with conditioning downforce. Break-in at the higher conditioning downforce helped in reaching faster stabilized values of the analyzed micro-texture parameters. The evolution of these parameters was different for the two different downforces, however as break-in time increased past 30 minutes, mean summit height and mean summit curvature began to approach approximately the same value. These results indicated that, for the particular disc used in this study, a change in the magnitude of downforce during pad break-in caused a change in break-in time and stable values for some micro-texture parameters. However, a

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Section: Introductionmentioning

confidence: 92%

Effect of Conditioning Downforce and Pad Break-In Time on Pad Surface Micro-Texture

McAllister

Stuffle

Sampurno

et al. 2018

ECS J. Solid State Sci. Technol.

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“…Since shear force is a result of mechanical interactions among the pad, the abrasive particles and the wafer, a higher average shear force should result in a higher mean removal rate for a nonchemically limited CMP process such as ILD CMP. Liao et al [12] correlated the ILD removal rate with shear force and characterized pad surface micro-texture by using laser confocal microscopy. Her investigation shows the feasibility of an on-line and non-destructive shear force detection method for determining the pad surface micro-texture during oxide CMP.…”

Section: Resultsmentioning

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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“…CMP typically refers to chemical mechanical planarization. As its name indicates, CMP simultaneously employs both chemical and mechanical actions to selectively remove the exposed material from elevated features for improved planarization [6][7][8][9][10][11][12][13][14]. Driven with the planarization challenge in IC manufacturing for smaller minimum feature size and more wiring levels, CMP was invented by International Business Machines (IBM) in the mid-1980s [15].…”

Section: What Is Cmp?mentioning

confidence: 99%

Lubrication in Chemical and Mechanical Planarization

Wu¹,

Liao²

2016

Advances in Tribology

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Chemical mechanical planarization (CMP) has been widely used in integrated circuit (IC) processing to achieve both local and global surface planarity through combined chemical and mechanical actions. The lubrication plays a significant role in CMP and can be determined by the Stribeck curve since it provides direct evidence of the extent of contact among wafer, pad asperities, and slurry particles. The advancements in the construction of the Stribeck curve are highlighted in this chapter. Traditionally, the procedure for constructing the Stribeck curve is as follows: (1) polish wafers at various pressures and sliding velocities to obtain the coefficient of friction (COF) values; (2) plot the experimental data as COF vs. Sommerfeld number; (3) construct the Stribeck curve via curve fitting. Recently, an alternative method was presented to construct the Stribeck curve via only performing one wafer polishing experiment. Pressure and sliding velocity are varied separately or together for a desired length of time, so that multiple measurements can be taken within one run. In this study, a back-propagation (BP) neural network is proposed to construct the Stribeck curve. Results show that the BP neural network could construct a more accurate Stribeck curve and thus could better provide insight into the lubrication mechanism of CMP processes.

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Effect of Pad Surface Micro-Texture on Removal Rate during Interlayer Dielectric Chemical Mechanical Planarization Process

Cited by 17 publications

References 18 publications

Effect of Conditioning Downforce and Pad Break-In Time on Pad Surface Micro-Texture

Effect of Conditioning Downforce and Pad Break-In Time on Pad Surface Micro-Texture

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

Lubrication in Chemical and Mechanical Planarization

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