Digital Optical Microscopy (VHX)

Digital Optical Microscopy Main Image
Large depth of field on 35-degree tilt angle

Optical microscopy is ubiquitous in diverse fields within academic research and commercial industries. It is an affordable, rapid analytical imaging technique used to visualize samples. While optical microscopes may be common, many instruments fall far short on performance when compared with the cutting-edge digital microscope systems available at Covalent.


  • High spatial resolution
  • Highly accurate and reproducible, in-situ, automated measurement of critical dimension
  • Widest possible depth-of-field (without cross-sectioning) among direct imaging / microscopy techniques
  • Rapid imaging and analysis easily adapted for high-throughput
  • Multi-modal illumination controls for enhanced feature contrast


  • Reduced spatial resolution compared to atomic force microscopy (AFM) / scanning probe microscopy (SPM), and some other optical profilometry methods

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Sample Requirements

Example Outputs

Automated Grain Size & Count on Wafer

Large depth of field on 35-degree tilt angle

3D image of bump in wafer packaging generated from 2D composite shot (which in turn integrates the focused pixels from numerous different focal planes, as shown at left).

From: Keyence

Instruments Used

Keyence VHX-6000

Keyence VHX-6000

  • Dynamic Microscope Tilt Range: -60° to 90° from vertical
  • Magnification Range: 20x to 2000x
  • Maximum Field of View 15.24 mm (lateral) x 11.40 mm (vertical) at 20x magnification
  • Illumination Modes: customizable bright-field, dark-field, and mixed lighting
  • High-precision, automated, in-situ dimensional analysis
View Instrument Brochure

How VHX Works

Advanced optical microscopes generate images in the same way modern digital cameras do, by capturing the light reflected back from (or transmitted through) a sample under set illumination. However, unlike a simple camera, modern optical microscopes also include intrinsic lens systems and sophisticated illumination systems that facilitate high magnification and dynamic range images with micron-scale resolution.

Our systems additionally incorporate extended depth-of-field optics, with automated compositing and image-stitching technologies to process and integrate images captured across different focal planes and oversized lateral domains. This enables fully focused, high-resolution imaging across the entirety of the desired field of view, even spanning large height differences in the features of interest. Distinct illumination modes (including: bright-field, dark-field, and mixed lighting, polarized lighting, and directional lighting) can be acutely controlled within a high-precision automation system to enable thorough characterization of critical surface features which may not otherwise be observable. In addition, this system has the unique ability to tilt the microscope with respect to the sample for enhanced edge definition images.