Bootstrapping de-shadowing and self-calibration for scanning electron microscope photometric stereo

Abstract

In this paper, we present a novel approach that addresses the blind reconstruction problem in scanning electron microscope (SEM) photometric stereo. Using only two observed images that suffer from shadowing effects, our method automatically calibrates the parameter and resolves shadowing errors for estimating an accurate three-dimensional (3D) shape and underlying shadowless images. We introduce a novel shadowing compensation model using image intensities for both cases of presence and absence of shadowing. With this model, the proposed de-shadowing algorithm iteratively compensates for image intensities and modifies the corresponding 3D surface. Besides de-shadowing, we introduce a practically useful self-calibration criterion by enforcing a good reconstruction. We show that incorrect parameters will engender significant distortions of 3D reconstructions in shadowed regions during the de-shadowing procedure. This motivated us to design the self-calibration criterion by utilizing shadowing to pursue the proper parameter that produces the best reconstruction with least distortions. As a result, we develop a bootstrapping approach for simultaneous de-shadowing and self-calibration in SEM photometric stereo. Extensive experiments on real image data demonstrate the effectiveness of our method.

A generic topography reconstruction method based on multi‐detector backscattered electron images

“…Interestingly, some authors have successfully applied the photometric stereo method by considering the detectors as optical light sources and the incident beam as the point of view. [22,23] The optical metaphor allows the connection to existing photometric stereo algorithms. However, it relies on the Lambertian scattering assumption to work.…”

Automatic extraction technique of CD‐SEM evaluation points to measure semiconductor overlay error

“…1 To secure a process margin, device manufacturers introduce ultrahighresolution exposure techniques such as optical proximity correction (OPC) and source mask co-optimization. Conventionally, special overlay marks arranged in scribe areas around circuit patterns were observed with optical microscopes or scanning electron microscopes (SEMs), 7,8 to measure alignment errors. In manufacturing processes, film deposition exposure, development, and other operations are performed repeatedly as layers are stacked, and one must manage pattern alignment among layers (overlay) in order to achieve high yield.…”

“…In manufacturing processes, film deposition exposure, development, and other operations are performed repeatedly as layers are stacked, and one must manage pattern alignment among layers (overlay) in order to achieve high yield. Conventionally, special overlay marks arranged in scribe areas around circuit patterns were observed with optical microscopes or scanning electron microscopes (SEMs), 7,8 to measure alignment errors.…”

Measurement Science and Technology moves further and faster

“…Mirroring last year's success the journal was pleased to announce in its July 2015 issue the award of as a many as five Outstanding Paper Awards. This year awards were presented in the areas of Fluid Mechanics [5], Optical and Laser-based Techniques [6], Precision Measurement [7], Sensors and Sensing Systems [8], and Biological, Medical and Life Sciences [9]. Many congratulations to all these authors.…”