UV-LED Tech in Photomask and Reticle Inspection

Take Your Precision Inspection Tools to the Next Level

In with Our UV-LED Light Sources, Up with Flexibility and Accuracy in Photomask and Reticle Inspection

A flawless reticle or photomask is crucial to achieving high yield in photolithography applications. Defects and contaminations cause pattern placement errors that are replicated repeatedly on production substrates. Reticle inspection systems help mask shops to qualify their photomasks and fabs to protect their yield by mitigating the risk of printing defective wafers and other substrates. Chipmakers, flat panel display (FPD), and PCB manufacturers rely on these system to assess incoming reticle quality and re-qualify reticles periodically during production.

Photolithography serves such a wide range of purposes that reticles come in too many varieties to count. Primelite focuses on inspection tools that identify defects and contaminations on large photomasks using near ultraviolet (NUV), visible (VIS), and near infrared (NIR) light. Powerful and flexible, our LED solutions replace conventional mercury and xenon discharge lamps in these systems.

Integration of Our LED Light Sources into Photomask Inspection Tools

High-resolution flat panel displays are much in demand for smartphones, tablets, and the like. OEMs are better equipped to meet this demand with our powerful LED tech integrated into their reticle inspection tools for large photomasks. The merits of Primelite’s high-performance LED systems are persuasive, with three very good reasons to opt for our solutions:
  1. Primelite’s fiber-coupled Advanced Light Engines ALE/1 and ALE/3 are phenomenally flexible. Our high-transmission LED Light Guides let you move and position the light source in your machine practically however and wherever you wish. These light guides are up to 20 meters long in some existing installations.
  2. Leading-edge OLED FPDs come with more TFT transistors to achieve better resolutions. This is why high-end photomasks have to be able to produce smaller feature sizes. To properly inspect these reticles, your setup must be more sensitive to defects. Shifting radiation wavelengths from VIS to near UV lends your equipment this enhanced ability to detect defects. Primelite’s Advanced LED Light Engines deliver excellent performance in the spectral range between 350 and 450 nm.
  3. Our LED exposure solutions’ superb output stability (both short- and long-term) adds to the accuracy and consistency of your reticle inspection results.
Primelite UV-LED Integration Reticle Inspection
Reticle inspection setup with Primelite UV-LED light source ALE/1
Primelite Fiber-Coupled UV-LED Spot Light Source ALE ONE: Spectral Power vs. Discharge Lamp
ALE/1 vs. 200 W discharge lamp: Spectral power (CWL 365 / 405 / 436 nm)

Precision Mono- and Multi-Wavelength Output

While other LED exposure solutions provide narrowband inspection light – for example, at around 385±15 nm – our advanced LED systems give you a broadband output spectrum that you can customize as you see fit. To complement the central wavelengths matching the i-, h-, and g-line (365 / 405 / 436 nm) of conventional discharge lamps, can add VIS components such as blue and green to the spectral range.

Our Advanced Light Engine ONE lets you combine up to five high-power, individually feedback-controlled LEDs into a single optical path. Cost-effective single- and dual-wavelength exposure setups are available based on our fiber-coupled UV-LED light source ALE/3.

Output Performance Compared

Output power [mW]1Broad­band
(350 - 450 nm)
(355 - 385 nm)
ALE/1.3 (CWL 365 / 405 / 436 nm)230,00010,000
ALE/3.2 (CWL 365 / 405 nm)213,0006,500
200 W Mercury discharge lamp (typical values)7,5003,000

1Power output measured at end of light guide (active core dia. 6.5 mm, length 1.5 m); deviation of ±10% possible
2CWL of emitters: 367.5±2.5 nm, 402.5±2.5 nm, and 435.0±2.5 nm

Primelite Fiber-Coupled UV-LED Spot Light Source Advanced Light Engine ONE
Primelite fiber-coupled UV-LED spot light source ALE/1 and LED Light Guide

Why ALE ONE and ALE THREE for Photomask Inspection:

Advanced Light Engine

ALE/1 UV-LED spot light sources raise the industry’s bar for tailored broadband exposure spectra and superb stability.

Advanced Light Engine

Need an affordable, small-footprint replacement for reticle inspection tools’ mercury discharge lamps? Here it is.

Light Guides

Learn more about how our high-transmission LED Light Guides can improve your photomask inspection setup.

Talk to us about your use case!