Application Guide

Semiconductor Inspection Lighting

Semiconductor inspection lighting should be selected from the target feature, surface geometry, material response, camera sensitivity, optics, speed, and sample images. Coaxial, diffuse, low-angle, line-scan, UV, IR, and SWIR approaches solve different contrast problems; a lighting family alone does not establish an inspection result.

Compare Spectral Lighting Prepare a Sample Test

Start withFeature and surface behaviorCompareGeometry and spectrumConfirm withSamples and production constraints

Lighting selection by inspection condition

Flat reflective marks, fiducials, or package surfacesCoaxial or on-axis illuminationStart where the camera needs controlled on-axis reflection from a largely planar target.

Glossy, curved, or mixed-height package surfacesDiffuse dome or multi-angle illuminationUse diffuse comparison tests when direct reflections hide marks or create unstable glare.

Shallow scratches, chips, edges, or directional textureLow-angle bar or directional lightingGrazing illumination can expose height and edge changes; test light direction against defect orientation.

Moving strips, films, or repeated high-speed featuresLine-scan lighting with synchronized controlBrightness, scan width, exposure, trigger timing, heat, and line speed must be assessed together.

Material contrast outside the visible rangeUV, IR, or SWIR comparisonOnly use a spectral approach after confirming camera, lens, filter, window, and sample material response.

Inputs before a recommendation

Target part, feature, defect examples, and representative good/bad images or samples.
Material, finish, coatings, substrate, reflectivity, and any known spectral constraints.
Camera, sensor response, lens, filter, field of view, working distance, and required resolution.
Exposure, trigger, motion, line speed, heat, cleanliness, enclosure, and mounting constraints.

Common selection limits

A lighting approach that works on a planar sample may fail on height variation or changing surface finish.
UV, IR, and SWIR setups need compatible cameras, optics, filters, and safety review.
High-speed illumination needs to be checked for exposure, thermal conditions, timing, and uniformity across the field.
Production comparison should include representative material and process variation, not one demonstration image.

Related engineering paths

Use line-scan lighting when the target is continuous or moving; use custom lighting when geometry, spectrum, mounting, or controller constraints cannot be resolved by a standard family.

Line-scan lights ? Coaxial lights ? Custom lighting

FAQ

Semiconductor inspection lighting questions

What lighting should be tested first for semiconductor inspection?

There is no single first choice for every semiconductor task. Start from the inspection objective and surface geometry: coaxial light is often compared for flat reflective features, diffuse lighting for glare control, low-angle lighting for directional surface change, and spectral lighting when the material response requires it.

When should SWIR or IR lighting be considered?

Consider IR or SWIR only when the target material or hidden structure may respond differently outside visible wavelengths and the complete imaging path supports that range. Camera sensitivity, lens and filter transmission, windows, illumination power, safety, and sample images all need confirmation.

What should be included in a semiconductor lighting sample test?

Provide representative good and defect samples or images, material stack or finish when available, target feature, camera and lens, field of view, working distance, line speed or exposure, desired wavelength range, and mounting or cleanliness constraints.