Known for innovation, Swiss firm Schneeberger AG Lineartechnik is currently developing a new positioning and movement system that will bear the name Double Gantry. Initial tests and analyses prove that speed of positioning can be almost doubled in applications such as wafer production. The Double Gantry should be on the market from mid-2014
Mobile telephones, tablets, laptops and many other, routine electronic products are becoming ever more efficient and/or smaller. This is due to the semiconductor chips, miniaturisation of which seems to be endless. Inserting and testing structures (data highways) in these tiny electronic parts requires systems whose accuracy of movement has to be within micrometres and nanometres. The major chip manufacturers also expect optimum speed, as this has a direct impact on profit. In addition to the optical system, in order to best satisfy the requirements efficient positioning units are in great demand in production and test facilities. They ensure that the wafers dotted with hundreds of chips are quickly and accurately positioned.
Schneeberger AG, based in Roggwil, Switzerland, is a leading provider of such movement systems. Markus Kindler, the company's Engineering Systems Manager, explains: "There are major differences between the precision requirements of our customers and end users. Ever greater positioning accuracy, which falls within tolerances of tens or hundreds of nanometres for a movement area of 250,000 mm2 is, however, expected with progressive miniaturisation." To explain: the ratio between a nanometre and a metre is roughly equivalent to the difference between the size of a hazelnut and the Earth.
Schneeberger has for years achieved the requisite approach and positioning precision. Amongst other things, use of hybrid materials combining carbon fibre and aluminium, for example, have played an important role in this. "We thus achieve a very high degree of rigidity at a low weight", explains Markus Kindler, adding: "The lower the masses to be moved, the faster and more accurately we can accelerate and brake. Improved dynamics mean that chip manufacturing systems are achieving higher throughputs, which is more economic."
Double Gantry: less weight, more speed
With their sights on greater efficiency, Schneeberger's engineers are currently developing a new positioning system, which has already been comprehensively tested. The initial results are a reason for Markus Kindler to expect a real quantum jump in terms of increased performance: "We are assuming that the Double Gantry will double positioning speed in semiconductor chip testing, which will ultimately considerably increase productivity."
The name Double Gantry reflects the decisive technical principle: two gantry axes are used. The X and Y axes are uncoupled. This is possible by arranging them in a cross and achieving independent movement through multiple guide rails. This innovative structure means the lower axis does not have to bear the weight of the upper axis, which massively reduces the lower axis's speed in the usual stacked configuration. In the Double Gantry, the X and Y axes each bear their own weight, as well as that of the axis of rotation, the wafer and the clamp system.
It is also important that Schneeberger uses a high-tech composite material, made of various carbon fibres and fitted with integrated attenuation layers. As far as Construction Group Manager Tom Fernández is concerned, this is an important detail: "This is how we manage to rapidly dissipate even minor oscillations in the system during positioning and to stabilise the system as quickly as possible." The use of recirculating ball-type steering, developed and manufactured in house, also helps. This is how the specialists achieve an optimum pulsation level with maximum rigidity.
Engineer Tom Fernández also mentions the shallow rotational axis, which has a centre line to top of just 26 mm, for a diameter of 300 mm, as another highlight. The centre of mass reduced in this way also ultimately contributes to increasing the positioning system's speed.
As of mid-2014, with the Double Gantry Swiss company Schneeberger AG will bring to market a positioning system which can almost double the production speed of wafer manufacturing production and testing systems. Schneeberger manufactures all the relevant parts itself – from the cast mineral base, via the miniature guidance, to the measuring systems.
Best values in terms of speed to precision
Speed and precision are equally important for achieving a high production speed. In the final analysis it's a question of approaching clearly defined structures as quickly and accurately as possible. Production speed suffers if a positioning system moves quickly to a defined position, but has to be adjusted there for a long time due to lack of precision. It is therefore worth approaching the predefined structures quickly and accurately.
Schneeberger's Double Gantry achieves this in an optimum manner thanks to the many different innovations. In figures: acceleration values of up to 5 Gs can be achieved when using a semiconductor test system, with positioning accuracy of 0.5 µm. If the precision that can be achieved is more important to the user, the Double Gantry is also capable of achieving 100-nanometre accuracy when positioning. Even then acceleration speeds of 2 Gs are still possible. Engineering Manager Markus Kindler adds: "It's impossible to make a general statement as to which setting achieves the best productivity. It depends entirely on the application. We're happy to help our customers to achieve the optimum results through appropriate adjustments."
Initial analyses and tests have shown that the Double Gantry contains enormous potential for productivity. Adrian Raible, Project Acquisition Manager, consequently expects numerous enquiries from this sector. He doesn't, however, want the new positioning system to be restricted to the semiconductor industry alone: "I'm sure that our Double Gantry's massive speed of production will also attract the attention of other businesses in the microelectronics industry. I can easily imagine applications in the solar industry and medical engineering. In any case we are perfectly ready to adapt our systems to different applications."
Markus Kindler (right), Engineering Systems Manager, and Tom Fernández, Mechanical Engineering and Calculation Group Manager with Schneeberger AG are sure that the new Double Gantry will facilitate enormous productivity increases in many industries: "The new construction arrangement allows much greater speed and precision."
Improved detail: superlight structural component
As one of the leading manufacturers of innovative positioning and movement systems, Schneeberger AG is always at pains to innovate. The company's engineers don't concentrate exclusively on complex system solutions such as the Double Gantry. The developers also place great emphasis on minor, detailed improvements. The latest example is a bionic laser welding structural component. The idea is that it should weigh less than half the weight of previous solutions, yet have the same rigidity and have the ability to be used in various positioning systems. The secret lies in the production process and the newly defined geometry that it makes possible.
This bionic laser welding structural component is supposed to weigh much less than half, but have the same rigidity.
Founded in 1923, Schneeberger is now one of the leading names when it comes to ground-breaking innovations in the field of linear technology. Linear bearings, profiled linear guideways, measuring systems, gear racks, slides, positioning systems and mineral casting are all part of Schneeberger’s product and manufacturing range. The company serves original equipment manufacturers operating in various industries worldwide – from solar and semiconductor technology to electrical and medical engineering, every field is represented. Schneeberger’s distributors and exclusive representatives can be found in all major industrial nations around the world, thereby guaranteeing the best possible proximity to customers everywhere.