In the world of high-performance machine development, the Netherlands is planted firmly on the cutting edge – particularly in the field of chip-making equipment, used in the semiconductor and electronics domain. To stay ahead of the ever-evolving demands and consumer expectations, key players in Dutch high tech are teaming up as part of the Imsys-3D public-private partnership to create next-generation high-performance motion systems.
When it comes to the world of silicon, the chips that are feeding the electronics boom, Dutch equipment and machine builders such as ASML and ASMI are planted at the top of their fields, globally. However, to keep a competitive edge in the production of state-of-the-art machines, companies like these must balance their customers’ current needs with innovation. Thanks to the public-private partnership of the Imsys-3D project, high-tech equipment makers are getting a big boost in planning for the future, as collaborators utilize cutting-edge technology to develop new and improved methods to build next-gen high-performance motion systems.
For the high-tech equipment industry, high-performance motion systems are a vital piece to the puzzle. However, to meet future performance targets and time-to-market demands, new design-optimization methods are much needed. Enter the Imsys-3D project team, which includes Delft University of Technology (TU Delft), mechatronics and motion control specialist MI-Partners, the industrial 3D-printing equipment manufacturer Additive Industries, lithography systems provider ASML and software company Infinite Simulation Systems. “Our goal for this project is to use computers to generate new designs for a wafer stage automatically,” explains Arnoud Delissen, PhD student at TU Delft. “By using unique algorithms, computers can design optimal shape and dynamic properties, which can then be 3D-printed, offering never before realized efficiency – allowing industrial partners to work toward the next generation of machines.”
In chip manufacturing equipment, the wafer stage, also called a chuck, is a crucial positioning module in the chip-making process. When the large disk or wafer of silicon is ready to be printed with a chip pattern, through the so-called lithography process, the silicon is placed by a robot on the magnetically-levitated stage, which moves very precisely under extreme ultraviolet (EUV) light – exposing only specific parts of the silicon to the light to print patterns. “The exactness and speed of this movement are critical for productivity, but fast motions easily trigger mechanical vibrations that destroy the accuracy of the lithography process,” describes Matthijs Langelaar, associate professor of computational engineering at TU Delft. “Making the chuck stiffer isn’t an easy remedy, since adding more mass results in higher forces as well.”
Typically, to solve this issue and limit the vibrations in wafer stages operating at high speed, it would take teams of engineers conducting dynamic optimization analysis – a real-time test and evaluation process of the mechanical design – to determine how best to control the movements for optimum precision. The Imsys-3D collaboration, however, is looking to automate and improve the procedure. “Currently, this is an iterative process where the mechanical designers create a design and pass it along to dynamics engineers for analysis. Then the system would move to a control engineer to determine what kind of control bandwidth we can get out of the machine,” describes Dick Laro, system architect at MI-Partners. “Several years ago, we started looking into how to make this more efficient and we set out to combine these three separate steps and integrate them into one, as part of a new integrated optimization process.”
“This integrated way of working can reduce the lead time of a stage design from several weeks to a single day, while also providing superior performance,” adds Delissen.
After years of planning, research and development, the collaborators were getting close to their goals, at least in simulation. Then, two years ago, the coalition was joined by Eindhoven’s Additive Industries, which brought its state-of-the-art 3D-printing capabilities using metal-based additive manufacturing (AM) technology. As a unit, the consortium focused its design work on topology optimization, aka generative design, which takes a 3D model and analyzes how to whittle away layers of excess material to achieve ultra-efficient designs, while still fitting the size, weight and functional requirements of the customer.
In designing their first demonstrator, collaborators adhered to a strict set of parameters from one of their industrial partners. The new chuck needed to have a specific shape, a weight profile of roughly 8 kilograms and needed to measure 400 by 400 by 50 mm – a very large volume in the metal 3D-printing world. “This is a real benefit of our system and metal AM technology, the complete freedom of shape and design – allowing the algorithm to optimize in a broader space,” highlights Harry Kleijnen, key account manager at Additive Industries. “We’ve created printed structures that you simply cannot create with any other technology available today. This is a major contributor to the uniqueness of this project and the promise of the future.”
“By utilizing these methodologies for topology optimization, we could fully exploit the flexibility offered by additive manufacturing. As Harry described, it gives you a lot of freedom, which you simply don’t have in conventional machining,” adds Laro. “By using this, we’ve been able to markedly improve the performance of the stage, which is important because it would be next to impossible for human minds to just develop that structure, which is now synthesized through the algorithm.”
First time right
While many development projects take years of trial and error and analysis, the Imsys-3D project team has made big strides in progress over a relatively short time. Though the collaborators have run into several challenges, ranging from changing dimensions of the stage requirements to the pure computational issues caused by the limitations of today’s technology, the group has already realized success. In fact, with all parties giving input throughout the optimization stage of the chuck, the final design was sent to Additive Industries and prepared for the first trial print. “Going into this last phase of the design, we reviewed the plans, allowing our team to bring in the specific AM constraints, like maximum angulation of surfaces, to be integrated into the algorithm, then it was ready to go,” recalls Kleijnen. “The design was perfectly suited to print. We printed two parts, which took roughly 10 days total – 5 days per part. We could achieve this in half the time, but we opted to play it safe for the initial print. In the end, the newly printed chuck was a total success from the very first time, which is a big step forward.”
Now, the aluminum-alloy wafer stage, weighing in at 8.5 kilos before processing, is heading to MI-Partners to be integrated into the machine and tested. Group expectations are that this newly printed chuck can offer twice the performance as its predecessors while limiting vibrations and ensuring precision and accuracy. “Going forward, our goal is to have a completely automated design process within a year,” expresses Langelaar. “MI-Partners will be working to fully integrate the chuck with the motion controllers to show the viability and potential gains to industrial stakeholders. In the end, we think this will offer unparalleled efficiency for those making the chips, which means cutting-edge technology can become more affordable to end-users and consumers.”