UV-LED Wafer Stepper Systems

Our UV-LED exposure solutions increase the efficiency of advanced packaging processes.

Broadband stepper systems, also known as 1X Steppers or Mini-Steppers play an essential role in 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 LEDs are prominent examples to be manufactured on those highly specialized stepper devices.

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 range between 350-450 nm. As we provide elevated radiation output, you can replace any conventional high-power mercury arc lamp up to 1 kW or even higher – without the hassle of mercury waste disposal and tool downtime while swapping lamps.

With a Primelite ALE/1 UV-LED exposure unit integrated into your stepper, you can target resolutions down to 1 µm or even in the sub-micron range. Furthermore, our stable and highly reliable UV-LED illumination units provide superior system throughput at a lower cost of ownership.

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I-Line, H-line, and G-line for Full Power

Many photolithography applications rely on broadband exposure encompassing i-, h-, and g-line (365/405/435 nm) radiation. We designed our ALE/1 UV-LED light sources to provide a very similar spectral output. This way, an upgrade of your existing photolithography process to UV-LED exposure requires as little adaptation as possible.

Apart from our broadband UV-LED exposure units, configurations with single (365 nm) or dual peak wavelengths (365/405 nm and 405/435 nm) are also available.

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Comparing our ALE/1 Platform with a Mercury Arc Lamp

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Integrating ALE/1 and ALE/1C UV-LED Illumination Units into Steppers

Our UV-LED exposure solution replaces conventional lamp houses based on mercury discharge lamp technology. There are two different designs to choose from:

• Our fiber-coupled system ALE/1, featuring flexible liquid light guides to be coupled into the integration optics of broadband steppers.
• Our built-in solution ALE/1C, which follows a distributed design approach with a Control Subsystem (CSS) separated from the Exposure Subsystems (ESS).

Both systems may be customized to perfectly fit into your stepper. Also retrofitting – replacing a conventional lamp house in an existing system – is possible.

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Super-fast Switching for Highest Accuracy

Switching time (0 to 100%) of our UV-LED exposure equipment 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. It gets even better for longer exposure cycles (e.g., 300 milliseconds).

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Highlights – Why ALE/1 and ALE/1C for Stepper Systems

• Single spot UV-LED light source for easy integration
• Stable, precise, consistent, high-intensity radiation output
• Flexible, polychromatic coverage of i-, h-, and g-line (350-450 nm), no need for optical filters
• Long service life and TCO benefits of UV-LED technology
• Improved operating safety unlike discharge lamps
• No extensive cooling needed (e.g., no nitrogen or CDA)
• No mechanical shutter needed (fast switching times below 1 millisecond)