Computer Science Internship: Continuous Wafermap as a Mathematical Model

Introduction

Continuous wafermap (CWM) is a mathematical model that is developed within ASML. The major goal of the CWM is to provide a continuous and differentiable representation of a wafermap while eliminating the noise from the discrete measured topography data.

The CWM tries to provide the most close-to-reality model of different contributors (a.k.a components) to the exposed wafer topography. This includes the bare wafer and the device topography as well as the measurement noise.
The CWM employs a least square fit minimization approach to provide the topography of each component separately. Some constraints in the form of penalty terms are added to ensure a physically meaningful representation of each component.

Your assignment

Within the Metrology Leveling group, we have two available assignments. Depending on your interests and the match, one of the following assignments will be assigned to you. When applying, please indicate your preference in a cover letter.

Assignment 1 - Repeated pattern recognition and removal

Despite applying the penalty terms, it is seen that in some cases there exist a crosstalk among the components of a CWM. As the device topography map has a repeated pattern, so is the crosstalk in the bare wafer map. It is crucial to detect the repeated device pattern in the bare wafer map and remove it as a post processing step.

The goal of this assignment is to gain a comprehensive understanding about the existing methods in the field of repeated pattern recognition. The literature review will be then followed by proposing the most feasible solution (with respect to accuracy and computation cost) to the existing problem. 

Assignment 2 - Constrained Continuous Wafermap

Despite applying the penalty terms, it is seen that in some cases the components obtain unexpected values. Therefore, it is beneficial to apply bound constraints to the minimization problem while avoiding iterative numerical approaches. 

The main goal of this assignment is to provide a mathematical approach to constrain the CWM components while having the least impact on the existing computation cost.

The start date of the assignments will be as soon as possible. The internship has a minimum duration of 5 months, for 5 days per week (minimum 3 days on-site).

Your profile

To be the perfect match for one of the internships, you:

• Are a master student looking for a graduation assignment in the field of Mathematics, Computer Science, Physics or a related technical field;

• You have experience in some of the following items: MATLAB, image processing, algorithm development, signal processing, mathematical optimization techniques and data analysis;

• Are capable to conduct independent research, and are a true teamplayer;

• Possess proficient communication skills in English, both written and verbally.

Other requirements you need to meet

• You are enrolled at an educational institute for the entire duration of the internship;

• You need to be located in the Netherlands to be perform your internship. In case you ‘re currently living/studying outside of the Netherlands, your CV/motivation letter includes the willingness to relocate.

• If you are a non-EU citizen, studying in the Netherlands, your university is willing to sign the documents relevant for doing an internship (i.e., Nuffic agreement).

Diversity and inclusion

ASML is an Equal Opportunity Employer that values and respects the importance of a diverse and inclusive workforce. It is the policy of the company to recruit, hire, train and promote persons in all job titles without regard to race, color, religion, sex, age, national origin, veteran status, disability, sexual orientation, or gender identity. We recognize that diversity and inclusion is a driving force in the success of our company.

Need to know more about applying for a job at ASML? Read our frequently asked questions.