A technique for rapid elimination of microbubbles for photochemical filter startup

Wu, Aiwen; Chow, Wailup

doi:10.1117/12.804691

Cited by 3 publications

(2 citation statements)

References 2 publications

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“…These trapped bubbles were observed in previous work we conducted on DTI with an aspect ratio of 30 [29]: We showed that a transition to full wetting inside the trenches led to the release of bubbles. In the literature, we find several techniques to remove and control bubbles suspended in fluids, such as degassing the fluid and avoiding pressure drops in the dispense system [30], the addition of surfactants to lower the surface tension [31], or using megahertz acoustic waves to control the bubbles [32]. Some of these techniques could prove useful to eliminate the bubbles and are envisaged for future study.…”

Section: Discussionmentioning

confidence: 99%

Indirect nanoscale characterization of polymer photoresist wetting using ultra-high frequency acoustic waves

Salhab,

Carlier,

Toubal

et al. 2023

Phys. Scr.

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The wetting of surfaces with patterns in the order of a hundred nanometers is often a complex phenomenon to analyze and control. In the semiconductor industry, whether it is during the surface cleaning steps or the deposition of the protective mask (photosensitive liquid resin that is then cross-linked), the conformity of the deposit of the liquid layer on the patterned surface must be perfect or else the functionality of the targeted electronic component will be compromised. Thus, understanding the surface wetting of these liquids allows the implementation of optimized processes. In this paper, we present a method of indirect wetting characterization of a photoresist based on ultra-high frequency (# GHz) acoustic waves. This resin is a commercial product called GKR 4602 (belonging to the KrF series of positive photoresists), which is coated in two different ways: either directly onto the surface of a patterned silicon wafer, or after application of a solvent, Propylene Glycol Ethyl Ether (PGEE), which then acts as a pre-wetting layer. The patterned wafer, playing the role of electrical insulation (Deep Trench Isolation, DTI) are 200 nm wide, deep trenches with a high aspect ratio (> 50). The originality of this paper lies in the validation of the acoustic characterization by direct observation of the wetting of the cross-linked resin. To do so, we used a FIB (Focused Ion Beam) microscope which allowed us to make cuts and capture localized images of the wetting state of the photoresist. Moreover, all the results obtained (resins and patterned silicon surfaces) are directly from the microelectronics industry (STMicroelectronics), showing that our method is fully compatible with an industrial approach.

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Section: Discussionmentioning

confidence: 99%

Indirect nanoscale characterization of polymer photoresist wetting using ultra-high frequency acoustic waves

Salhab,

Carlier,

Toubal

et al. 2023

Phys. Scr.

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“…Each filter was installed using a recommended priming sequence. 1,2,3 Following the priming sequence, up to 3 liters of the Si-HM material was purged through the system, which included the pump, dispense lines, and dispense tip. After various volumes of material were purged, wafers were coated for on-wafer defect analysis.…”

Section: Methodsmentioning

confidence: 99%

Point-of-use filter membrane selection, start-up, and conditioning for low-defect photolithography coatings

Brakensiek

Cronin

2013

SPIE Proceedings

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Recent innovations in device design, including FinFETs and metal gate technologies, have required similar innovation in lithographic materials and process development. Complex processes such as double patterning and multilayer imaging require new and novel material chemistries to meet the rigorous defect level requirements for successful yield. To address these complex processes, new materials for multilayer imaging, including spin-on hardmask layers and thick carbon underlayers, have been introduced. These two types of materials have different roles in the multilayer imaging scheme, and likewise the chemistries that are used in these materials are different. To evaluate the wide variety of materials, it is necessary to be able to install them on a coater-track quickly and efficiently and to ensure that the chosen filter uses the best available filtration settings to provide the best-performing material. Typically end users of point-ofuse filters will install a new filter, which will be primed with the best-known method, and purge chemical until a defect baseline is reached.This study examines the interaction between a spin-on hardmask chemistry and membrane materials, examining decreasing pore size and the differential pressure increases. Under these conditions, known issues with particles, microbubbles, or oddly timed defect excursions should be able to be avoided with the proper selection and start-up of the filter.An Entegris IntelliGen ® Mini dispense system with Impact ® 2 filters was used to test different filtration settings on various filtration membranes and determine the best settings for each membrane type. These pumps have the capability to control differential pressure across the filter based upon its operating parameters. Results of this investigation will show that for the spin-on hardmask material, optimizing differential pressure across the filter by adjusting the IntelliGen ® Mini operating parameters will ultimately reduce blanket coat defect levels. As well, reducing pore size yields a greater impact to reduction of post-coat defect counts.

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Improving material-specific dispense processes for low-defect coatings

et al. 2010

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Minimizing defects in spin-on lithography coatings requires a careful understanding of the interactions between the spinon coating material and the filtration and dispense system used on the coating track. A wet-developable bottom antireflective coating (BARC) was examined for its interaction with polyamide and UPE media when utilizing the Entegris IntelliGen ® Mini dispense system. In addition, a new method of priming the filter and pump is described which improves the wetting of the filter media, preventing bubbles and other defect-generating air pockets within the system. The goal is to establish plumb-on procedures that are material and hardware specific to avoid any defect problems in the coating process, as well as to gain a better understanding of the chemical and physical interactions that lead to coating defects. Liquid particle counts from a laboratory-based filtration stand are compared with on-wafer defects from a commercial coating track to establish a correlation and allow better prediction of product performance. This comparison in turn will provide valuable insight to the engineering process of product filtration and bottling at the source.

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A technique for rapid elimination of microbubbles for photochemical filter startup

Cited by 3 publications

References 2 publications

Indirect nanoscale characterization of polymer photoresist wetting using ultra-high frequency acoustic waves

Indirect nanoscale characterization of polymer photoresist wetting using ultra-high frequency acoustic waves

Point-of-use filter membrane selection, start-up, and conditioning for low-defect photolithography coatings

Improving material-specific dispense processes for low-defect coatings

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