Thermal Modelling and Control of an Optical System

ALTEN participates in the development of the thermal modelling for controller design of the optical path in high-end lithography machines.

In lithography systems, light is used to print patterns on wafers that are used in computer chip production. This light should not be distorted too much by whatever mirrors and lenses it encounters on its way to the wafer, while the light also heats up these mirrors and lenses, causing them to deform a bit. In most high-end lithography machines, the specifications are so tight that this effect becomes relevant. Combine this with a push for higher production speed (and thus higher heat loads), it should come as no surprise that active control is required. To design the controllers, considering mirror and lens temperatures, a suitably accurate model is needed.

ALTEN activities

  • Expanding and improving the model’s machine emulation abilities
  • Verification and improvement of control strategies
  • Discussing and collaborating with suppliers

ALTEN added value Knowledge

  • Thermal dynamics
  • Controller design
  • Software development

Software and skills

  • Azure DevOps and GIT
  • Unit testing


Progressively elaborated updates of the model have been released to the stakeholders for various tests. The next milestone will be validation of the model with real-life machine data.