Primelite's UV-LED Light Sources for Wafer Edge Exposure: Cost-Efficient, Powerful, and Extremely Reliable
Wafer Edge Exposure (WEE) is a common step in high-volume semiconductor manufacturing. WEE processes a round edge and the ID region of a wafer after exposure using lithography tools such as wafer steppers. Fabs add this high-intensity exposure to their production line to increase the yield of semiconductor devices from the wafer. WEE allows for an absolute minimum exposure width at the wafer edge to minimize yield loss (positive resist) or to protect the edge from contamination during further handling (negative resist). WEE equipment can be connected to a semiconductor wafer track as a stand-alone unit or integrated directly into stepper equipment.
As it stands, most WEE applications use broadband radiation in the spectral range between 350 and 450 nm. The most common solutions are conventional fiber-coupled mercury discharge lamps with a rated power of 150 to 500 W. Finding more economical and reliable alternatives to these system setups was difficult because WEE requires broadband exposure. Enter Primelite’s Advanced Light Engines ALE/1 and ALE/3, which are designed to deliver their optical output via flexible LED Light Guides: Both systems cover the spectral range of conventional mercury discharge lamps and easily outperform the typical intensities required in wafer edge exposure processes.
System Integration in Wafer Edge Exposure Setups
WEE hardware consists of a scanner, a spinning device, and a powerful spot light source with optics to expose the wafer edge. Our UV-LED light sources ALE/1 and ALE/3 fit right into these setups: They are the only available solid-state lighting solution covering i-, h-, and g-line for broadband exposure of the wafer edge. Primelite’s ecofriendly UV-LED light sources ALE/1 and ALE/3 provide precisely controlled output to ensure highly accurate exposure results. Our exposure systems can also boost your equipment’s day-to-day operating efficiency. For one, the longer service life of UV LEDs means less tool downtime. For the other, all our light sources feature field-replaceable LED modules for fast, easy maintenance.
With an output spectrum much like that of mercury discharge lamps, our fiber-coupled UV-LED light sources are also particularly suitable for replacing conventional lamp technology in existing WEE processors.
Broadband for Full Power
A quick comparison between Primelite’s broadband UV-LED light sources and solutions powered by conventional mercury discharge technology shows an excellent spectral match while revealing a significant performance gap. Let our UV-LED Exposure Systems put you in the driver’s seat: Configure and drive the i-, h-, and g-line – the spectral range around the central wavelengths 365, 405, and 436 nm – individually, or use them all together for need maximum output. Exposure operations are remarkably precise at a millisecond switching time and remain stable over the long term.
Output Performance Compared
| Output power [mW]1 | Broadband (350 - 450 nm) | i-line (355 - 385 nm) |
|---|---|---|
| ALE/1.3 (CWL 365 / 405 / 436 nm)2 | 30,000 | 10,000 |
| ALE/3.2 (CWL 365 / 405 nm)2 | 13,000 | 6,500 |
| 200 W Mercury discharge lamp (typical values) | 7,500 | 3,000 |
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
Why ALE ONE or ALE THREE for Wafer Edge Exposure:
- Fiber-coupled UV-LED light source for easy system integration
- Output intensity of up to 90,000 mW/cm2
- Single wavelength and broadband exposure: i-, h-, and g-line (350 - 450 nm)
- Excellent short as well as long-term light output stability and precision
- Fast 1-millisecond switching
- UV-LED technology for longer service life and lower TCO
- Safer than discharge lamps
- Ecofriendly UV-LED light source with no expensive waste disposal
Advanced Light Engine
ONE
Our Advanced UV-LED Light Engine ONE has proven its merits in WEE use cases with its excellent long-term process stability and accuracy.
Advanced Light Engine
THREE
Learn more about our precision UV-LED light source ALE/3, a remarkably affordable replacement for discharge lamps in wafer edge exposure.