In EUV-photolithography tools, wafers are temporarily fixed to the wafer stage by means of electrostatic clamping. Such clamping is required to fixate the wafer at nanometer precision such that the photolithographic patterns can be applied with similar precision.

However, it is often observed that residual charge accumulation on the electrostatic clamp insulating surface can lead to unstable clamping force. Over time this effect negatively affects machine performance. This unwanted effect is also a limiting factor for future development where higher clamping forces are required.

In this research project we aim to characterize the exact influence of possible surface charge sources and define possible mitigation methods. This will be done with experiments on a model system combined with theoretical knowledge of charging processes, thereby laying a scientifically sound basis for future prevention of (uncontrolled) charging of insulator surface. These mitigation methods may be adapted to other related high-tech equipment where similar surface charging phenomenon occur.

Research questions which we will answer in this project are:

1. Which of the possible charging mechanisms are dominant in the surface charging of wafer stages?
2. What ways are there to diminish or control these dominant mechanisms?
3. Are there ways to make a surface more robust against (unpredictable) surface charging
4. Are there ways to (easily) remove surface charges in situ?

• A master's degree (or an equivalent university degree) and an excellent academic record in <physics and/or electrical engineering>.
• A research oriented strong attitude towards experimental physics or electrical engineering with a focus on plasma physics and/or high voltage technology.
• Ability to work in a team and <interested in collaborating with the industrial partners>.
• Fluent in spoken and written English.

• A meaningful job in a dynamic and ambitious university with the possibility to present your work at international conferences.
• A full-time employment for four years, with an intermediate evaluation after one year.
• To support you during your PhD and to prepare you for the rest of your career, you will have free access to a personal development program for PhD students (PROOF program).
• A gross monthly salary and benefits in accordance with the Collective Labor Agreement for Dutch Universities.
• Additionally, an annual holiday allowance of 8% of the yearly salary, plus a year-end allowance of 8.3% of the annual salary.
• A broad package of fringe benefits, including an excellent technical infrastructure, moving expenses, and savings schemes.
• Family-friendly initiatives are in place, such as an international spouse program, and excellent on-campus children day care and sports facilities.