What If a Lens Could Draw a 0.1-Millimeter Line with Light Reflected from Several Hundred Meters in the Air

Perspective drawing of a semiconductor exposure device

Perspective drawing of a semiconductor exposure device, an ultraprecise machine comprising a light unit, lens, wafer stage and wafer-stepping device
--- Correct me if I'm wrong, but an exposure device basically burns circuit patterns on the wafer, right? Sakai: Yes. When I explain my work to my family and friends, I tell them it's like a machine to develop film from cameras.--- Which means that the lens is very important. Sakai: It would be impossible to develop this kind of device without high-performance lenses.--- Exactly what kind of lens are we talking about? Kanda: At the lowest line width, 110 nanometers, or 0.11 microns...--- Hold on a minute. That's too small even to imagine. Maybe we could start with the size of the lens system? Sakai: Well, the thickness of the lens barrel is about the span of a man's arms, and its height is about that of a child.--- I see. So let's call it 60 centimeters in diameter and 150 centimeters in height. Now, if we enlarge that size by 1,000 times, we get a lens with a diameter of 600 meters and a height of 1,500 meters. That would make your lens about the size of an average tornado. Sakai: … (Laughs)--- And the distance between the wafer and the lens is? Kanda: Imagine several dozen centimeters.--- Okay. So, a tornado-size lens aims light at a wafer from several hundred meters in the air. Looking up from the ground, this would be like a scene in a science fiction film, when the main character looks up to see a beam of light coming from a UFO. And the chip on the wafer would be? Kanda: About 22 square millimeters...--- At 1,000 times, about 22 square meters, or the size of a tennis court. Kanda: Lines as fine as 0.11 microns are drawn on the wafer surface.--- One millimeter is 1,000 microns, which in our example means...0.11 millimeter lines!? So, what we're saying is that a lens the size of a tornado focuses light onto a tennis court to precisely draw lines the width of a human hair! Kanda: And the focus of the lens is limited to the scale of 0.2 microns. The lens and wafer must always be kept that distance apart. Very severe conditions, wouldn't you agree?--- The distance from the tennis court to the tornado lens has to remain stable within 0.2 millimeters? Kanda: Well, only if you magnify everything by 1,000 times. (Laughs)