Providing high-intensity UV exposure at the i-, h-, and g-line to replace traditional discharge lamps.

The semiconductor industry makes vast use of high power radiation in the blue, violet and ultraviolet spectral ranges for exposure of complex microstructures. Producing integrated circuits (microchips), liquid crystal displays (LCDs), printed circuit boards (PCBs) or MEMS (Microelectromechanical Systems) are major applications involving micro- or photolithography.

There is a strong trend in the industry to move away from the traditional discharge lamp technology, which has long been the light source of choice in semiconductor production. Retrofitting or designing new manufacturing equipment employing solid-state lighting is now facilitated by integrating Primelite Advanced Light Engines as a subsystem. Being a high-performance feedback controlled spot light source, it perfectly meets the challenging requirements regarding output stability. In order to optimize effectiveness in combination with selected photoresists, the spectral output of ALE/1 systems is customizable.

 


 

Integration of ALE/1 in Semiconductor Lithography setups

The ALE/1 replaces the conventional lamp house based on discharge lamp technology in a mask aligner (or wafer stepper). The light guide is coupled into the integration optics of the mask aligner. Due to very fast switching times (on/off), no mechanical shutter is needed.

Schematic illustration of ALE/1 implementation
Schematic illustration of ALE/1 implementation

 

Highlights – why ALE/1 for Semicondutor Photolithography

  • Single spot light
  • Stable, precise, consistent, high-intensity radiation output with limited calibration needed
  • Flexible, polychromatic coverage of i-, g-, and h-line
  • Long lifetime and TCO benefits of LED technology
  • Improved operating safety unlike discharge lamps
  • Future-proof mercury-free light source
  • No extensive cooling needed (e.g., nitrogen)
  • No mechanical shutter needed

 


 

Semiconductor Photolithography Solutions


i-line (365nm) Lithography
 
This ALE/1-setup provides highest radiation intensity focusing on a key single peak wavelength in photolithography – the i-line at 365nm. If your system is optimized for a single wavelength spectrum and does not profit from a broad spectrum, the ALE/1.1 is your preferred choice for high radiation output based on LED technology. The total radiation output ranges from 5,500 to 11,500mW (respectively 3,800 to 7,900mW in the range 365±10nm).

 

i-Line (365nm)
Wafer 100mm / 4” 150mm / 6” 200mm / 8”
Exposure area 80cm² 180cm² 320cm²
Radiation on surface*
in mW/cm²
LG Ø 5mm 35 15 10
LG Ø 6.5mm 60 25 15
LG Ø 8mm 30 20
* Assuming 50% efficiency of exposure optics.

 

Using an ALE/1.1 for i-line exposure would allow for intensities of up to 60mW/cm² on the exposure plane (100mm wafer example; given a 50% efficiency of the projection optics).

 


ihg-line broadband (365/405/435nm) Lithography
 
Many photolithography applications rely on broadband exposure at the i-, h-, and g-line (365/405/435nm). Replacing discharge lamp technology with Primelite’s ALE/1 platform allows for retaining the existing photo resists. Combining multiple wavelengths results in elevated output performance. The ALE/1.3 combined with a Ø 5mm light guide can provide intensities of up to 95mW/cm² on a 100mm diameter wafer. For larger areas (e.g., 200mm wafer) a setup with a Ø 8mm light guide represents a suitable solution with up to 45mW/cm².

 

ihg-Line (365/405/435nm)
Wafer 100mm / 4” 150mm / 6” 200mm / 8”
Exposure area 80cm² 180cm² 320cm²
Radiation on surface*
in mW/cm²
LG Ø 5mm 95 40 25
LG Ø 6.5mm 155 70 40
LG Ø 8mm 80 45
* Assuming 50% efficiency of exposure optics.

 


Scalable, high intensity photolithography solutions (1kW+)
 
Currently one ALE/1 is capable of replacing discharge lamps of up to 1kW (depending on the application). In case higher radiation output is required a combination of two (or three) ALE/1 using a randomized Y-fiber light guide is a potential option. Using that option would allow for higher intensities at the application surface (see figure below).

Multi-ALE/1-Setup for High Performance Applications
Multi-ALE/1-Setup for High Performance Applications

 

Multi-ALE-Setup
Wafer 150mm / 6” 200mm / 8” 300mm / 12”
Exposure area 180cm² 320cm² 710cm²
Radiation on surface*
in mW/cm²
2 ALE/1 & LG Ø 9mm 95 55 25
2 ALE & LG Ø 11mm 110 60 30
3 ALE & LG Ø 11mm 145 80 35
* Assuming 50% efficiency of exposure optics.

 


 

For more information on the product properties, technical concept and specifications of our systems please see Advanced LED Light Engines.