Precision Mechanics

A successful design starts with a complete set of specifications and a good concept. But the design detailing must also be accurate.

Is the required stiffness met? Are the material stresses within limits? Is there no hidden stick-slip? Does the assembly meet its accuracy when all production tolerances are accounted for? What are the failure modes? These questions can all be answered in the design phase.

Vink System Design & Analysis has solid experience in this type of precision engineering analysis. Some examples of projects are:

  • Tolerance analysis;
  • Wafer Stage Redesign;
  • Improved Wafer Table Flatness;
  • Adjustable Lens Element Development.

Tolerance analysis

Keywords: tolerances, budgets, statistics
Assemblies often have to meet stringent accuracy requirements. For example, an actuator range must have a sufficient range, a sensor and sensor-target must mutually be aligned, or the height of an assembly must be accurate. Tolerance analysis of mechanical assemblies is an essential step in the design and manufacturing of high quality products. Vink System Design & Analysis has great expertise in tolerance budgeting and analysis and has conducted several projects for MAPPER Lithography, ASML and Fontijne Grotnes.

Tolerance analysis course

Keywords: training course, tolerances, budgets, design process, lecturer
Jaap Vink, on the instruction of Mikrocentrum, organises the three-day training course Tolerance Analysis at companies internally. The course suits anyone who wishes to grasp a greater understanding of the effects of tolerances in structures and be able to discuss this. This includes designers, design engineers, product or production managers and purchasers.

The course teaches the course participant to solve tolerance issues structurally. He is further taught how complex tolerance studies can be clarified to others, and how the design process can be managed in relation to tolerance aspects. In addition, the course participant is taught how a design can be assessed from a tolerance management perspective.

Further information can be found at the Mikrocentrum website, where you can also enrol.

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Wafer Stage Redesign

Keywords: forces, budgets, qualification, specifications
The wafer stage is one of the sub-systems in ASML’s wafer scanners and steppers. A wafer stage positions the wafer while integrated circuits (ICs) are being exposed. New specifications were drafted for all air bearings as part of this wafer stage redesign project. Bearing forces were analyzed during a preliminary study and then all variables were fine-tuned to arrive at an optimal balance between air usage, bearing force and air gap. Qualification of the first prototype bearings was performed using a separate test bed, as well as after integration into a wafer stage.

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Improved Wafer Table Flatness

Keywords: mechanisms, root cause, budgets, accuracy, cost price
The wafer stage is one of the sub-systems in ASML’s wafer scanners and steppers. A wafer stage positions the wafer while integrated circuits (ICs) are being exposed. The wafer table is the carrier that holds the wafer during the exposure process. The wafer table’s flatness directly affects the performance of ASML’s steppers and scanners. This analysis investigated how a higher degree of wafer table flatness could be achieved without increasing the cost price. The study demonstrated that improved construction and assembly processes, as well as improved mechanical specifications on paper, could reduce flatness deviations by as much as 30 to 50%.

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Adjustable Lens Element Development

Keywords: performance, hysteresis, accuracy, specifications
The heart of ASML’s wafer scanners and steppers is the projection lens. This lens exposes the wafer with its integrated circuit (IC) pattern. In cooperation with Zeiss and Philips, a design for an adjustable projection lens element was derived. Sub-system specifications were also drafted, as well as the design for the adjustable lens element’s actuator.