An optical exposure machine in a clean room in the Netherlands under amber yellow light, a tall narrow cabinet two metres high on a grey plinth, its frame light grey, its sides of clear plastic panels showing bundled cables, optical tubes and a wafer table inside, on the table a round mirror-grey wafer fifteen centimetres across catching the light, on top a plain black lamp box, at its right a low attached work table with white plastic containers, a hand in a white glove setting a wafer cassette into the attached unit, a technician in a white clean-room suit seen from behind, perforated floor tiles.
What it was used for
The PAS 2500 was the wafer stepper with which ASML followed the PAS 2000; chiphistory.org calls it the system that built the company. By ASML's own company history, Philips and Advanced Semiconductor Materials International founded the firm in 1984; it began in a leaky shed next to a Philips office in Eindhoven, moved to a factory and office in Veldhoven in 1985 with 100 employees, and brought the PAS 2500 to market in 1986, the PAS 2000 having appeared in 1984. Kato's chronology gives the 1987 i-line version, the PAS 2500/40, a numerical aperture of 0.4, 0.7 micrometre resolution and 70 wafers per hour on 150 millimetre wafers.
What was new
The PAS 2000 was, according to chiphistory.org, not a new design but a redesign from the frame of the Philips SIRE II stepper; its main customer, by Kato, was Cypress Semiconductor. The barb lies in the position of the firm that now dominates lithography: ASML describes itself in those years as cash-devouring, with few customers and unable to stand on its own two feet; ASMI withdrew its investment, Philips announced cost cuts, and the company continued only after the Philips board member Henk Bodt persuaded his colleagues to provide a final round of funding. On the same account, the decisive customers came only with the PAS 5500 of the early 1990s.
What the sources leave open: The technique field calls the PAS 2500 modular; none of the sources opened describes it expressly that way, so the word does not appear in the text. Nothing was found on unit numbers, price or customer list for the PAS 2500. ASML's page is the company's account of itself.