Small shock absorbers during handling: Customized protection for every axle

In the semiconductor industry, structure downsizing is leading to smaller, more efficient, faster and more cheaply produced integrated circuits. With the advances in microelectronics, the demands on the handling systems responsible for the clean, safe transport of the wafers are increasing. In a custom application, 10 miniature shock absorbers from ACE provide protection from each linear axis.

Photolithography is a key technology in the manufacture of microelectronic components and circuits and in the production of microsystems. In this process, a structural pattern is transferred from a photomask to a photo-structurable, light-sensitive, thin layer of photoresist on a wafer. To ensure their flawless production, designers take the utmost care in both programming the automated processes and monitoring the sequences. Due to the demand for microprocessors and memory chips, and because fail-safety is the be-all and end-all in wafer production, many chip manufacturers work with in-house subcontractors in the area of handling systems. These can be involved in the manufacturing processes without too much risk and usually equip their designs with high-quality, proven standard components for drives, controls and linear axes. In order to secure the latter in the best possible way by robust, mechanical, current-independent machine elements, which can also be used in clean rooms, cooperations with ACE Stoßdämpfer GmbH take place. Another essential reason for the cooperation is that the company from Langenfeld offers customer-specific solutions in addition to a large variety of catalog products. These are precisely adapted by an experienced team of engineers from ACE to the requirements of the semiconductor manufacturers by precisely designing each component via software and then testing it in ACE's test laboratory. In this way, they work with customers to ensure that all production axes are effectively protected to eliminate damage during handling.

Design, simulation, test bench: How ACE turns standard dampers into unique specimens

As the company name suggests, one of ACE's strengths is in the field of shock absorption technology. Originally from the USA, the manufacturer was the first to bring adjustable industrial shock absorbers to the market almost 60 years ago. The company, which has been part of the Stabilus Group since 2016, also offers design engineers components such as industrial gas springs, rotary brakes, clamping elements, and numerous other solutions for decoupling vibrations, among other things. In this context, small and industrial shock absorbers as well as safety shock absorbers have remained a central business area of ACE. The unique know-how associated with these products has been continuously expanded over the years by the development engineers in the USA and in Europe, so that it also leads to the results desired by the customer in this application.

For chip production, high-precision, frictionless axes are installed in a handling system for the application in question. According to the manufacturer, in the event of a crash, their X and Y axes, as well as the center pole axis (CP), may only be loaded with maximum permissible forces in order to ensure 100 percent that the entire system is not damaged. Accordingly, in this application, the three axes had to be equipped with three different types from ACE's range of small shock absorbers. Four small shock absorbers with M20 thread are used for the Y-axis, four for the X-axis, but with M18 thread, and two for the CP-axis with thread size M25.

In the first step, ACE determined together with the customer the appropriate damper type for each of the three axles, which had to meet the exact specifications given by the customer. In addition, ACE engineers were given the maximum tolerated support force in case of a crash. In the case of the Y-axis, for example, the following parameters were broken down to one damper each: Mass, m = 95.85 kg and velocity, v = 1.08 m/s, thus corresponding to a kinetic energy of 55.90 Nm. The maximum permitted support force for this axis was 5,700 Nm. Based on this information, the ACE development department then simulated the bore pattern accordingly for the type of small shock absorber that could be considered for the mass forces and speed of the electric drive mentioned. As the figure (Fig. 3) shows, it was possible to decelerate energy and speed uniformly over the entire stroke of 14 mm, bringing the maximum support force down to a value of approx. 5,300 Nm. ACE was also able to meet the specified values for the best possible protection of the other two axes by mechanical components. In a third and final step, the small shock absorbers, which were tailor-made according to the simulation results, were delivered to the high-tech customer after extensive tests. There, the 10 small shock absorbers from ACE have since then provided customized protection on all three motion axes of each handling system used in wafer production.

Damping technlology

ACE Calculation services & Tools

Author: Robert Timmerberg M. A., Specialized journalist, plus2 GmbH, Düsseldorf

Pictures: ACE Stoßdämpfer GmbH