Reduction of photoresist usage during spin coating

Chou, Fu–Chu; Wang, Min-Wen; Gong, S.C.; Yang, Zen-Gi

doi:10.1007/s11664-001-0055-6

Cited by 6 publications

(4 citation statements)

References 17 publications

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“…They found that spreading is initially dominated by the impinging jet, but later resembles droplet spreading. 23,24 Additionally, researchers have investigated the effects of altering the surface of the substrate. Some have considered the effects of altering the geometry of the substrate, 11,25 although the present paper focuses on flat substrates.…”

Section: Introductionmentioning

confidence: 99%

Evolution of rivulets during spreading of an impinging water jet on a rotating, precoated substrate

et al. 2019

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The spreading of a liquid film across a rotating surface is inherently unstable due to the centrifugal force, which causes the formation of rivulets along the spreading front. This instability produces a rich diversity of spreading patterns and is important to control for the optimization of spin-coating and spin-rinsing of silicon wafers during the fabrication of microelectronics. The present work is an experimental investigation of the evolution of rivulets arising from this instability during the spreading of an impinging water jet across a rotating substrate that is precoated with a thin, aqueous film. To characterize these rivulets, we developed a high-speed imaging apparatus and image-processing software that traces the spreading front over time. We show how the morphology of the spreading front is qualitatively affected by varying the Reynolds number of the impinging jet, the ratio of centrifugal to Coriolis forces, and the type of liquid used to precoat the substrate. For quantitative analysis of rivulets, we measured the "compactness ratio" of the spreading front, which quantifies deviation from a circular spreading front. We used the compactness ratio to demonstrate that rivulets are suppressed most strongly at low rotation rates, at high flow rates, and on substrates precoated with water, although with notable exceptions.

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Section: Introductionmentioning

confidence: 99%

Evolution of rivulets during spreading of an impinging water jet on a rotating, precoated substrate

et al. 2019

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“…The development of film thickness distributions during the injection stage depends on the wafer rotation speed, 4) injection rate, and injection time. Recently, numerical simulations of the continuous film spread and flow visualization on a commercial spin coater have been reported by Chou et al, 5) who found that controlling the injection time and increasing the injection rate can reduce the amount of liquid injected. However, no comprehensive study or data on injection rate or injection time was provided.…”

Section: Introductionmentioning

confidence: 99%

“…[6][7][8] At a given instant the rotation velocity rapidly increases, driving the radial spreading of the liquid. In the current microelectronics industry, a nozzle usually dispenses a stream of photoresist onto the surface of a high-spinningspeed wafer 5,9) to meet the requirement of high throughput and better uniformity. As the coating liquid spreads, a capillary ridge forms near the advancing contact line, and the liquid front becomes susceptible to azimuth perturbations, leading to finger deformation.…”

Section: Introductionmentioning

confidence: 99%

Effects of dispensing flow rate on fingering instability during spin coating

Wang

Hourng

2014

Jpn. J. Appl. Phys.

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To reduce the amount of material used and to understand the phenomenon of viscous fluid spread during the early stage of spin coating, in this study, we perform flow visualization experiments. The results show that, in the early stage of spin coating, the spreading of viscous fluid is mainly governed by the initial liquid dispensation flow rate. Then, fingering instability is induced by the centrifugal force. The critical radius and time for the onset of instability increase with increasing initial dispensing flow rate under a constant spin speed. However, the effect of dispensing flow rate on the critical time and radius are almost negligible as long as the whole volume of liquid has been dispensed before the onset of fingering instability. This means that the fluid was almost completely dispensed over the coating surface within a limited time and that the effect of the dispensing flow rate attainable is insignificant. Furthermore, once a dispensing fluid with a much lower viscosity is used in spin coating, a much larger dispensing Reynolds number can eliminate the effect of the dispensing rate, and thus the effect of Coriolis force cannot be neglected in spin coating.

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“…To effectively reduce the running cost of photoresist consumption, coating a maximum radius of liquid film with a minimum amount of liquid was studied. [1][2][3] However, the largest radius that a liquid film can cover is limited by the formation of instability rivulets or ''fingers'' at the leading edge of liquid front. The largest radius is also called critical radius (R c ), meaning the radius corresponding to the onset of fingering instability.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Contact Angle of Spreading Thin Film on a Rotating Disk

Chou¹,

Lai²,

Zen³

2008

jjap

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The effect of dynamic contact angle on fingering instability during spin coating is investigated by flow visualization experiment. A modified rotational Bond number, which demonstrates the dynamic contact angle of fluid front that affects the dimensionless critical radius, is proposed in this work. For high rotational Bond number, the variation in dimensionless critical radius is not linearly proportional to the rotational Reynolds number because of the variation in critical contact angle if the relaxation time is fixed at zero. By modifying the rotational Bond number with the change in critical contact angle, the dimensionless critical radius becomes a function of the modified rotational Bond number.

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Reduction of photoresist usage during spin coating

Cited by 6 publications

References 17 publications

Evolution of rivulets during spreading of an impinging water jet on a rotating, precoated substrate

Evolution of rivulets during spreading of an impinging water jet on a rotating, precoated substrate

Effects of dispensing flow rate on fingering instability during spin coating

Dynamic Contact Angle of Spreading Thin Film on a Rotating Disk

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