Equipment

Qualification of microlenses on wafer level

Qualification of microlenses on wafer level

Automated micro-lens array testing system SHSInspect autoLab suitable for glass substrates up to 300 mm x 300 mm

Qualification of microlenses on wafer level

View on both 40X objectives during a through-light testing on a micro-lens array fabricated on a 100 mm x 100 mm glass substrate.

The usage of glass material for the development of micro-optics via the microsystem technology platform is increasing drastically compared to the standard polymer techniques. Glass possesses particular features, being more suited in terms of optical properties, transparency and temperature stability.

Well-established micro-lens technologies such as hot embossing, casting, milling or mask-based photolithography show some fabrication irregularities especially in the outer regions of the wafer. The discrete properties of individual lens elements made in one- and two-dimensional arrays are not measurable in short time. Although random tests are commonly made they are not enough  to control the quality of the micro-lenses producing a negative influence on the amount of discarded lenses.

SHSInspect autoLab is capable of fully automated reflective and refractive measuring tests   of micro-optics in the visual spectral range with an aperture between 50 µm and 250 µm.
The system can also measure other parameters such as aperture, ROC, EFL, sphericity, conic, lens position and tilt on the wafer, as well as the surface profile by optical profilometry in no additional time.
All parameters can be used for a sample qualification in terms of a PASS/FAIL analysis of each micro-optic element or the whole substrate.