Project Summary
A customer wanted to add through-silicon imaging capability to an existing visible-light inspection microscope without modifying the original system.
Using the Jay Photonics Modular Imaging Arm, infrared transmission imaging was added while preserving the microscope's optics, stage, and workflow.
The resulting configuration enabled imaging through approximately 1 mm of silicon using the microscope's original objectives from 4X to 20X.
1. Background
Silicon is opaque in the visible spectrum but becomes transparent at infrared (IR) wavelengths, where photon energy falls below its bandgap. This enables IR transmission imaging to reveal subsurface structures in silicon devices non-destructively [1,2].
This capability is widely used in semiconductor inspection, including wafer inspection, chip testing, and quality control, where access to buried features is essential. IR imaging supports defect detection, coating evaluation, and metrology in semiconductor manufacturing.
While dedicated infrared inspection systems exist, many laboratories and industrial facilities already rely on optical microscopes for routine inspection and analysis. Extending the capabilities of these existing platforms to perform through-silicon imaging can provide a practical and cost-effective solution while preserving familiar workflows and equipment.
2. The Challenge
Our client wanted to add through-silicon imaging capability to an existing microscope platform without modifying the microscope itself. The objective was to preserve the original optical system, mechanical configuration, and day-to-day workflow while enabling visualization of structures embedded within silicon.
The challenge was therefore to introduce IR transmission imaging in a way that was fully reversible, non-invasive, and compatible with the microscope's existing objectives and imaging components.
3. The Approach
Jay Photonics enables through-silicon imaging by combining an IR illumination source with a dedicated proprietary camera. This technology is designed to be independent of microscope brand or model, allowing integration into a wide range of optical systems through a modular imaging arm (Figure 1).
This approach enables the integration of Jay Photonics technology into instruments that users already know and trust, preserving familiar workflows while enabling new imaging capabilities.
Figure 1. Jay Photonics modular imaging arm system, including the transmission module, LED controller, infrared camera, and sample stage, designed to enable through-silicon infrared imaging on standard optical microscopes.
The imaging arm functions as a compact transmission module positioned on the microscope stage. The sample is placed on a small glass platform at the top of the arm, while the illumination is delivered from below. A Jay Photonics camera is mounted on the microscope’s imaging port to capture the transmitted light. This configuration enables infrared transmission imaging through the sample while fully leveraging the microscope’s existing objective lenses.
The system is designed for seamless integration, requiring no permanent modification to the microscope while retaining standard objectives and mechanical stages. The camera is mounted via standard microscope ports, ensuring compatibility with existing platforms. By preserving established imaging workflows, the solution is well suited for both temporary experiments and long-term installation.
4. Methodology
System under test: The evaluation was performed using the Jay Photonics modular imaging arm integrated into a standard optical microscope, shown in Figure 2. The arm was installed on an Olympus BX53 microscope, enabling IR transmission imaging without modifying the original system.
The modular arm functions as a compact transmission module positioned on the microscope stage. The sample is placed on a glass platform at the top of the arm, while infrared illumination is delivered from below. A Jay Photonics camera is mounted on the microscope’s imaging port to capture transmitted light.
Figure 2. Jay Photonics modular imaging arm installed on an Olympus BX53 optical microscope, demonstrating integration of the transmission module into an existing microscope platform without permanent mechanical modification.
This configuration enables through-silicon imaging using the microscope’s existing objectives, preserving standard imaging conditions and workflows.
Sample: The sample used in this study consists of a two-layer silicon integrated circuit structure, with each layer having a thickness of approximately 500 µm.
5. Imaging Performance
Infrared transmission imaging was performed on the silicon integrated circuit sample using the Olympus microscope equipped with the Jay Photonics modular imaging arm. Images were acquired at multiple magnifications (4x, 10x, and 20x) to evaluate the system performance across different spatial scales.
Internal structures within the stacked silicon layers are clearly observable using IR illumination. The transmitted signal reveals the features embedded within the sample, demonstrating effective light propagation through the combined thickness of approximately 1 mm of silicon.
Figure 3 shows that at lower magnification (4x), a large field of view enables global inspection of the sample, allowing rapid identification of overall structures and regions of interest. Increasing magnification (10x and 20x) provides enhanced spatial resolution, revealing finer details within the integrated circuit layout.
Figure 3. Infrared transmission images of a two-layer silicon integrated circuit acquired using the Jay Photonics modular imaging arm on an Olympus BX53 microscope with standard objectives at 4X, 10X, and 20X magnifications, demonstrating clear visualization of subsurface structures and the transition from large-area inspection to higher-resolution imaging.
6.Conclusion
The Jay Photonics modular imaging arm brings powerful through-silicon infrared imaging capabilities to standard optical microscopes. By combining optimized infrared illumination with a dedicated imaging configuration, it enables clear visualization of subsurface structures in silicon devices using conventional microscope optics. This approach significantly lowers the barrier to adopting infrared inspection in existing laboratory environments.
Across multiple magnifications, the system provides both large-area inspection and detailed structural observation, supporting a wide range of inspection and analysis needs.
This modular solution offers a practical and efficient path to advanced semiconductor imaging and metrology without replacing existing equipment.
7. Interested in a Custom Project?
Jay Photonics enables the integration of infrared imaging capabilities directly into existing microscope platforms, without disrupting established workflows.
If you are interested in bringing through-silicon imaging to your current system, we invite you to contact us and explore a solution tailored to your setup and application.
References:
[1] Huang, Andrew'bunnie. "Infra-Red, In-Situ (IRIS) Inspection of Silicon." arXiv preprint arXiv:2303.07406 (2023).
[2] Tarifa, Allyson, and Nuggehalli M. Ravindra. "Optical properties of crystalline silicon in the infrared." TMS Annual Meeting & Exhibition. Cham: Springer Nature Switzerland, 2023.