ABB Semiconductors is a leading manufacturer of power semiconductors and the center of expertise for the entire ABB group. Two types of semiconductor elements are manufactured in the Lenzburg (Aargau) clean rooms: conventional, proven bipolar transistors and the newer, even harder to make BiMOS devices with IGBT chips. Dedicated production lines are used for each type. The products are distinguished by their switching properties and power ratings and can be precisely tuned to match application requirements.
ABB has been investing 150 million Swiss francs to expand the semiconductor manufacturing plant and reinforce its market leadership. The facility has started operations in April 2010. This expansion will substantially increase production capacity, which will help manage the ongoing demand and ensure that quality and delivery reliability are maintained.
Four application fields
One area of application is power transmission and distribution, where the semiconductors are used to switch power currents in the megawatt range in microseconds. For example, the high-voltage DC transmission line that runs from the Three Gorges Dam to the coastal city of Shanghai in China uses this technology. The line transmits power for about six million households across a distance of 1,100 kilometers. A second example is the environmentally friendly underwater link between Norway and the Netherlands, called the NorNed link. About 1,800 thyristors (bipolar technology) from Lenzburg are used in the two converter stations.
A second application area is industry, where ABB power semiconductors are becoming more and more indispensable; for example, in drives for ship propulsion or gas compressors, or rectifiers for large-scale aluminum smelters, cement plants or chlorine production facilities.
A third application area is railways. Semiconductors are also used for traction drives in the railways market. Every major, respected railway manufacturer the world over uses high power ABB technology from Lenzburg.
A fourth application area is renewable energies. One example is the link between the world’s largest offshore wind farm BorWin 1 and the onshore grid which will be launched in 2010. This system too relies on power semiconductors made in Lenzburg.
More than 200 process steps required to go from silicon crystal to finished chip
High-voltage DC transmission systems (HVDC) transport electric power over long distances and convert it back to AC at the destination. Converter stations with power semiconductor components – ultra thin silicon chips that switch power in microseconds – are used to convert the power from DC to AC and vice versa.
Cleaner than an operating room
These highly sensitive semiconductor elements are produced under exceptionally clean conditions. ABB Semiconductors employees in Lenzburg wear protective clothing, hoods, gloves, face protection and special shoes and look more like surgeons than production workers.
The clean rooms in which the highly sensitive IGBT silicon wafers for HVDC Light power transmission systems are produced are far cleaner than an operating theater. The room air is filtered, the temperature held constant and vibration minimized. A maximum of ten particles no larger than 0.0005 millimeters in diameter per cubic meter of air is permitted – otherwise product quality would be compromised. Compare this to a human hair, the diameter of which is 0.076 millimeters.
Very sophisticated process
The silicon discs, called wafers, are not much thicker than a human hair. They are built up, layer on layer, until they have the properties required for lightning-fast current switching. This task is accomplished using high tech equipment and an extremely sophisticated two-hundred-step process. Atoms are implanted or migrate deeper into the material when it is placed in diffusion furnaces operating at temperatures of up to 1,250 degrees Celsius. In the yellow room, photolithography is used to structure the silicon wafers, and afterward they are immersed in various baths in the etching room. Each of these process steps is applied multiple times; that is, for every layer. In the final step, the wafers are accurately cut to size.
After the silicon semiconductor element has been completely manufactured it is subjected to an elaborate testing process. Twenty-five voltage and current properties are measured for every chip at various frequencies and temperatures.
Quality defines performance
To raise production quality, ABB Semiconductors employees employ internationally leading Six Sigma methodology and tools to statistically capture, evaluate and optimize all processes.
Chip quality is paramount. It defines the switching speed, the rating and the life of a power-semiconductor element. A one-centimeter-square silicon chip made in Lenzburg is able to switch high currents on and off several thousand times per second. This would be like fully accelerating and decelerating a Formula 1 racecar in fractions of a millisecond!
For further information contact:
+ 41 58 585 00 00
ABB Switzerland, May 2012