High-Throughput DIC Imaging for Materials and Semiconductor Inspection

The Challenge:

High-throughput inspection of semiconductor wafers, surface coatings and other materials requires imaging systems that deliver exceptional contrast without sacrificing speed. While traditional DIC microscopy provides high-contrast imaging of subtle surface features, it relies on plane-polarized light. This requires the sample to be aligned with the orientation of the polarized light, creating a bottleneck and adding complexity to automated workflows when inspecting complex parts with features in multiple orientations.

The Solution:

An automated Circular Differential Interference Contrast (C-DIC) configuration built on the Zaber Nucleus® microscopy platform. By using circularly polarized light, the system eliminates angular dependence of the sample, allowing complex features in any orientation to be imaged immediately. The automated microscope system combines high-contrast imaging, ultra-repeatable sample positioning and rapid switching between imaging modes to maximize inspection throughput.

The Engineering Approach:

Our Custom Engineering Team leveraged the modularity of standard Nucleus microscope components to build a unique, cost-effective C-DIC configuration. Rather than designing a fully custom system from scratch or relying on the expensive standard of mounting a DIC slider below each individual objective, we modified standard parts to mount a single C-DIC slider on a motorized actuator in the infinity space behind the objective.

• This shared-slider design allows up to four unique objectives on the standard X-MOR4 objective turret to share a single C-DIC slider, significantly reducing the overall system cost.
• The analyzer module is housed in our standard X-FCR06 motorized filter cube turret, enabling rapid, automated switching between brightfield and C-DIC imaging modes.
• For maximum throughput, the optical assembly integrates directly with Zaber direct drive linear motor XY stages (capable of speeds up to 750 mm/s) synchronized with high-speed line scan and TDI cameras.