A hybrid 2D/3D inspection concept with smart routing optimisation for high throughput, high dynamic range and traceable critical dimension metrology

Abstract

Dimensional surface metrology is required to enable advanced manufacturing process control for products such as large-area electronics, microfluidic structures, and light management films, where performance is determined by micrometre-scale geometry or roughness formed over metre-scale substrates. While able to perform 100% inspection at a low cost, commonly used 2D machine vision systems are insufficient to assess all of the functionally relevant critical dimensions in such 3D products on their own. While current high-resolution 3D metrology systems are able to assess these critical dimensions, they have a relatively small field of view and are thus much too slow to keep up with full production speeds. A hybrid 2D/3D inspection concept is demonstrated, combining a small field of view, high-performance 3D topography-measuring instrument with a large field of view, high-throughput 2D machine vision system. In this concept, the location of critical dimensions and defects are first registered using the 2D system, then smart routing algorithms and high dynamic range (HDR) measurement strategies are used to efficiently acquire local topography using the 3D sensor. A motion control platform with a traceable position referencing system is used to recreate various sheet-to-sheet and roll-to-roll inline metrology scenarios. We present the artefacts and procedures used to calibrate this hybrid sensor system for traceable dimensional measurement, as well as exemplar measurement of optically challenging industrial test structures.

Real‐Time Metrology for Roll‐To‐Roll and Advanced Inline Manufacturing: A Review

“…approximately 22 µm in sample space per pixel). [47] In the second common type of web inspection, laser scanning, continuous-wave or pulsed laser light is raster scanned over the web repeatedly, and the scattered light is detected by a fast, sensitive single-pixel detector. The detector optical response can be very fast due to its single-pixel readout, so scan speed is usually limited by the mechanical inertia of the laser scan instrument.…”

3D roughness standard for performance verification of topography instruments for additively-manufactured surface inspection

“…For the present work, both for operational reasons and for professional curiosity, the scanned optical point profilometer route was explored for reference measurements of the 3DRS-II. The reference instrument used was an NPLdeveloped industrial metrology test platform [15], configured as a large-area chromatic confocal microscope (CCM) [16] for the reported work. Townsend et al [5] noted that only 11% of examined literature reported the application of the wider confocal family of measurement techniques to AM surfaces.…”

Thermal and dimensional evaluation of a test plate for assessing the measurement capability of a thermal imager within nuclear decommissioning storage

“…The 3D optical profilometer used was an NPL-developed hybrid 2D/3D measurement platform [11] configured as a large-area Chromatic Confocal Microscope (CCM), capable of measuring the complete areal topography of the plate in one operation. The measured topographies were then used to calculate individual plate feature dimensions.…”