Quartz crystal microbalance gravimetry measurements of the sorption of trimethylaluminum into polystyrene and poly(methyl methacrylate)

Liu, Yifan; Ramprasad, Rampi; Losego, Mark D.

doi:10.1016/j.matchemphys.2022.127026

Cited by 5 publications

(1 citation statement)

References 63 publications

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“…QCM experiments were performed in a hot-walled custom-built VPI reactor described elsewhere. , The QCM used is a Phoenix high-temperature film thickness sensor PC-based system purchased from Colnatec. A polished gold 6 MHz RC quartz crystal was used as the substrate for the poly(methyl methacrylate).…”

Section: Methodsmentioning

confidence: 99%

Dealkylation of Poly(methyl methacrylate) by TiCl₄ Vapor Phase Infiltration (VPI) and the Resulting Chemical and Thermophysical Properties of the Hybrid Material

Balogun,

Yim,

Yom

et al. 2024

Chem. Mater.

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This study examines the chemical reaction pathways for vapor phase infiltration (VPI) of TiCl 4 into poly(methyl methacrylate) (PMMA). VPI is a processing method that transforms organic polymers into organic−inorganic hybrid materials with new properties of interest for microelectronic patterning, technical textiles, and chemical separations. Understanding the fundamental chemical mechanisms of the VPI process is essential for establishing approaches to design the chemical structure and properties of these hybrid materials. While prior work has suggested that TiCl 4 infiltration into PMMA does not disrupt the polymer's carbonyl bond, a clear reaction mechanism has yet to be proposed. Here, we present a detailed X-ray photoelectron spectroscopy study that presents evidence for a concerted reaction mechanism that involves TiCl 4 coordinating with the PMMA's ester group to dealkylate the methyl side group, creating a chloromethane byproduct and primary chemical bonds between the organic and inorganic components of the hybrid material. Additional spectroscopy, quartz crystal microbalance gravimetry, and thermophysical and chemical property measurements of this material, including solubility studies and thermal expansion measurements, provide further evidence for this chemical reaction pathway and the subsequent creation of inorganic cross-links that network these TiO x −PMMA hybrid materials.

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Section: Methodsmentioning

confidence: 99%

Dealkylation of Poly(methyl methacrylate) by TiCl₄ Vapor Phase Infiltration (VPI) and the Resulting Chemical and Thermophysical Properties of the Hybrid Material

Balogun,

Yim,

Yom

et al. 2024

Chem. Mater.

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Vapor‐Phase Infiltrated Organic–Inorganic Positive‐Tone Hybrid Photoresist for Extreme UV Lithography

Subramanian,

Tiwale,

Lee

et al. 2023

Adv Materials Inter

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Continuing extreme downscaling of semiconductor devices, essential for high performance and energy efficiency of future microelectronics, hinges on extreme ultraviolet lithography (EUVL) and addressing associated challenges. One of such challenges is a need for improved EUV photoresists featuring simultaneously high sensitivity, resolution, and etch selectivity. Here, a new, positive‐tone, organic–inorganic hybrid EUV photoresist is demonstrated that delivers a high‐resolution EUVL and electron‐beam lithography (EBL) patterning capability combined with high sensitivity and etch resistance. The new resist, poly(methyl methacrylate) infiltrated with indium oxide (PMMA‐InOx), is synthesized via vapor‐phase infiltration (VPI), a material hybridization technique derived from atomic layer deposition. The weak binding of the gaseous indium precursor, trimethylindium, to the carbonyl group in PMMA allows the synthesis of hybrids with inorganic content distributed uniformly in the resist, enabling high EUVL and EBL sensitivities (18 mJ cm−2 and 300 µC cm−2, respectively) and high‐resolution positive‐tone EUVL patterning (e.g., 40 nm half‐pitch line‐space and 50 nm diameter contact hole patterns) with high Si etch selectivity (>30–40). The low exposure doses required to pattern the PMMA‐InOx hybrid resist, high etch resistance, and processing strategies, which are developed, can pave the way for using infiltration‐synthesized hybrid thin films as reliable positive‐tone EUV photoresists for future semiconductor patterning.

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Depolymerization and Etching of Poly(lactic acid) via TiCl₄ Vapor Phase Infiltration

Balogun,

Losego

2024

J. Phys. Chem. C

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This study investigates the use of TiCl 4 vapor phase infiltration (VPI) to cleave ester groups in the main chain of a polymer and drive depolymerization and film etching. Prior investigations have demonstrated that the infiltration of TiCl 4 into PMMA results in dealkylation of its ester bond, cleaving its side groups. This study investigates the VPI of TiCl 4 into poly(lactic acid), which is a prototypical polymer with an ester group in its main chain. Utilizing in situ quartz crystal microbalance (QCM) measurements and spectroscopic ellipsometry, PLA is observed to depolymerize readily at 135 °C with extended TiCl 4 precursor exposure, resulting in significant thickness and mass reduction, whereas at 90 °C, depolymerization is significantly slower and etching is negligible. Utilizing Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and a residual gas analyzer (RGA), dealkylation is shown to be the primary depolymerization mechanism. FTIR and XPS analyses reveal the consumption of carbonyl and methoxy groups and the emergence of hydroxyl, chlorine, and titanium moieties. In situ RGA measurements provide further insights into the byproducts formed during the TiCl 4 and water exposure steps, indicating that the depolymerized components undergo further breakdown into other substances. Residuals left after 135 °C TiCl 4 VPI are easily removed with a 0.1 M HCl aqueous solution. These findings highlight the expanding functionality of VPI, revealing its capability as both an additive and subtractive process and suggesting its broader applications.

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Quartz crystal microbalance gravimetry measurements of the sorption of trimethylaluminum into polystyrene and poly(methyl methacrylate)

Cited by 5 publications

References 63 publications

Dealkylation of Poly(methyl methacrylate) by TiCl₄ Vapor Phase Infiltration (VPI) and the Resulting Chemical and Thermophysical Properties of the Hybrid Material

Dealkylation of Poly(methyl methacrylate) by TiCl₄ Vapor Phase Infiltration (VPI) and the Resulting Chemical and Thermophysical Properties of the Hybrid Material

Vapor‐Phase Infiltrated Organic–Inorganic Positive‐Tone Hybrid Photoresist for Extreme UV Lithography

Depolymerization and Etching of Poly(lactic acid) via TiCl₄ Vapor Phase Infiltration

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Quartz crystal microbalance gravimetry measurements of the sorption of trimethylaluminum into polystyrene and poly(methyl methacrylate)

Cited by 5 publications

References 63 publications

Dealkylation of Poly(methyl methacrylate) by TiCl4 Vapor Phase Infiltration (VPI) and the Resulting Chemical and Thermophysical Properties of the Hybrid Material

Dealkylation of Poly(methyl methacrylate) by TiCl4 Vapor Phase Infiltration (VPI) and the Resulting Chemical and Thermophysical Properties of the Hybrid Material

Vapor‐Phase Infiltrated Organic–Inorganic Positive‐Tone Hybrid Photoresist for Extreme UV Lithography

Depolymerization and Etching of Poly(lactic acid) via TiCl4 Vapor Phase Infiltration

Contact Info

Product

Resources

About

Dealkylation of Poly(methyl methacrylate) by TiCl₄ Vapor Phase Infiltration (VPI) and the Resulting Chemical and Thermophysical Properties of the Hybrid Material

Dealkylation of Poly(methyl methacrylate) by TiCl₄ Vapor Phase Infiltration (VPI) and the Resulting Chemical and Thermophysical Properties of the Hybrid Material

Depolymerization and Etching of Poly(lactic acid) via TiCl₄ Vapor Phase Infiltration