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High aspect ratio anisotropic silicon etching for x-ray phase contrast imaging grating fabrication

Materials Science in Semiconductor Processing

Finnegan, Patrick S.; Hollowell, Andrew E.; Arrington, Christian L.; Dagel, Amber L.

Lab based x-ray phase contrast imaging (XPCI) systems have historically focused on medical applications, but there is growing interest in material science applications for non-destructive analysis of low density materials. Extending this imaging technique to higher density materials or larger samples requires higher aspect ratio gratings, to allow the use of a higher energy x-ray source. In this work, we demonstrate the use of anisotropic silicon (Si) etching in potassium hydroxide (KOH), to achieve extremely high aspect ratio gratings. This method has been shown to be effective in fabricating deep, uniform gratings by taking advantage of the etch selectivity of differing crystalline planes of silicon. Our work has demonstrated a method for determining Si crystalline plane directions, specific to (110) Si wafers, enabling high alignment accuracy of the etch mask to these crystalline planes.

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TYPE Journal Article YEAR 2019
DOIOSTIScopus

Double sided grating fabrication for high energy X-ray phase contrast imaging

Materials Science in Semiconductor Processing

Hollowell, Andrew E.; Arrington, Christian L.; Resnick, Paul J.; Volk, Steve; Finnegan, Patrick S.; Musick, Katherine M.; Dagel, Amber L.

State of the art grating fabrication currently limits the maximum source energy that can be used in lab based x-ray phase contrast imaging (XPCI) systems. In order to move to higher source energies, and image high density materials or image through encapsulating barriers, new grating fabrication methods are needed. In this work we have analyzed a new modality for grating fabrication that involves precision alignment of etched gratings on both sides of a substrate, effectively doubling the thickness of the grating. We have achieved a front-to-backside feature alignment accuracy of 0.5 µm demonstrating a methodology that can be applied to any grating fabrication approach extending the attainable aspect ratios allowing higher energy lab based XPCI systems.

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TYPE Journal Article YEAR 2019
DOIOSTIScopus
Results 26–50 of 82
Results 26–50 of 82