Precision and impulse decoupling for link trimming

Background

Eitzenberger GmbH, based in Wessobrunn in the Munich metropolitan region, develops high-precision solutions for air bearings and air bearing systems for a wide range of industrial applications, including the semiconductor industry. Their solutions are characterized by extreme accuracy, high dynamics, and a compact design, while also being suitable for cleanroom environments. With the Dynamic Wafer Stage EZ-GS0760, Eitzenberger has implemented a globally unique positioning system featuring dual impulse decoupling in the X and Y axes.

Task

The Dynamic Wafer Stage is used in a laser micromachining system. The system can process both 200 mm and 300 mm wafers and impresses with high throughput and precise process control. During link trimming, microscopically fine conductor paths (fuses) on memory chips, sensors, or micro-LEDs are selectively cut by laser radiation. This enables the activation, programming, or deactivation of specific circuits to ensure the functionality of the chip in case defects are detected during the test cycle. The application requires extremely precise three-dimensional positioning and stable laser focusing — with structure sizes of only 1–2 µm, a required positioning accuracy of < 100 nm, and repeatability of < 40 nm.

Bilz was commissioned to design the vibration isolation for the Dynamic Wafer Stage. The aim was to protect the sensitive laser processing during link trimming from disruptive environmental and floor vibrations. The challenge was to find a solution that meets both the mechanical requirements and cleanroom compatibility while integrating seamlessly into the compact system architecture.

Solution

For the highly efficient vibration isolation of the Dynamic Wafer Stage, Bilz BiAir® membrane air springs ED-AL-E with mechanical level control were used. The air springs ensure a stable working environment in which the sensitive laser processing can run without interference.

Additionally, Bilz precision levelling wedges PKA-AL were installed beneath the machine frame. They provide precise and reproducible positioning of the Dynamic Wafer Stage and contribute to mechanical stability. The wedge mounts enable exact leveling and support uniform load distribution — a key factor for process reliability during highly dynamic scanning movements.

The combination of BiAir® air springs and Bilz precision levelling wedges offers a reliable, low-maintenance, and space-saving solution for vibration isolation in high-precision semiconductor processes.