UV-LED Illumination in Wafer Steppers

We provide powerful UV-LED solutions for step-and-repeat lithography systems.

Primelite's UV-LED illuminators redefine the efficiency of advanced packaging processes

Broadband wafer steppers, also known as 1X Steppers or Mini-Steppers play an essential role in today’s advanced packaging applications, such as Fan-Out Wafer-Level Packaging (FOWLP), Wafer-Level Chip-Scale Packaging (WLCSP) or Through Silicon Via (TSV). Complex microstructures like MEMS or LED’s are prominent examples to be manufactured on those highly specialized step-and-repeat lithography systems.

Our broadband UV-LED light sources ALE/1 and ALE/1C are a perfect fit, if you want to upgrade your stepper to UV-LED illumination. By adopting our solution, you gain full flexibility on the choice of photosensitive advanced packaging materials you may need to apply in your process.

It is a unique setup that we use: Combining individual LED-Modules around the i-, h-, and g-line into one optical path allows you to have full control on the spectral composition of your broadband exposure in the 350-450 nm range. As we provide high-power radiation output, you can replace any conventional mercury arc lamp with a rated power of up to 1,000 W or even higher. Forget about tool downtime while swapping lamps and the hassle of mercury waste disposal. With our UV-LED technology integrated in your lithography tool, this is a thing of the past.

Our systems prove themselves daily in countless semiconductor manufacturing applications. Using our high-performance UV-LED illumination technology in a wafer stepper, you can achieve resolutions down to 1 µm or even in the sub-micron range. The excellent output stability and reliability substantially facilitate the industry’s efforts to leverage system throughput (WPH) while bringing the cost of ownership down.

Integration of our UV-LED illuminators in broadband Wafer Steppers

Our UV-LED exposure solutions replace the conventional lamp house and eliminate the need for the primary beam folding mirror, heat sink to absorb radiation over 450 nm, shutter, and filters. In many cases, our LED Performance Optics are also an economical alternative for existing homogenizing / condensing components. You have two options to upgrade your wafer stepper from mercury arc lamps to our UV-LED illumination:

  1. If your design envelope is challenging, check out our all-in-one fiber-coupled UV-LED light source ALE/1, featuring flexible liquid light guides to be coupled into the integration optics of broadband steppers.
  2. Our high-power UV-LED exposure system ALE/1C follows a distributed design approach with a Control Subsystem (CSS) separated from a small footprint Exposure Subsystem (ESS) replacing the conventional lamp house of the wafer stepper.

We can customize both solutions to perfectly fit into your equipment. Retrofitting your existing system is also possible.

i-line, h-line, and g-line combined for full power

Many photolithography applications rely on broadband exposure encompassing i-, h-, g-line (CWL 365/405/436 nm) radiation. We have ensured that our UV-LED exposure systems provide a very similar spectral output to the mercury discharge lamp. This way, an upgrade of your existing photolithography process to UV-LED exposure requires minimal adaption. Setups with two central wavelengths (365/405 nm or 405/436 nm) are also available.
Primelite UV-LED Exposure System ALE ONE C: Spectral Power (CWL 365/405/436 nm)
Primelite UV-LED Exposure System ALE ONE C: Spectral Power (CWL 365/405/436 nm)

Output performance compared

Output Power [mW]Broad­band
(350-450 nm)
(355-385 nm)
Mercury Discharge Lamp (typical values)
  500 W25,00012,000
  1,000 W50,00025,000

1Standard mode; Performance mode with chiller delivers additional 20% output.

Excellent exposure accuracy

Switching time (0 to 100%) of our UV-LED exposure solutions is below 1 millisecond. Furthermore, an internal closed-loop feedback control system guarantees constant radiation output over short as well as longer exposure cycles. These features permit dose accuracies of ±0.2% for short 50-millisecond shots just by using a timer. The accuracy even increases for longer exposure cycles (e.g., 300 milliseconds).

Primelite Lithography UV-LED Exposure System ALE ONE C
Primelite Lithography UV-LED Exposure System ALE/1C (Controller and Exposure Subsystem)

Why Primelite's UV-LED illuminators for Wafer Steppers:

Advanced Light Engine

Our ALE/1 is the benchmark fiber-coupled UV-LED spot light source for reliable output and customizable broadband exposure spectrum.

Advanced Light Engine

Achieve resolutions down to 1 µm or even in the sub-micron range with our industry-proven UV-LED exposure system ALE/1C.

Talk to us about your application!