Lithography and etching

Light transfers a pattern onto a surface, and chemicals or plasma then remove everything the pattern leaves exposed.

20 lines that use it

Camera sensor 6 stations · 15 raw sources Compact disc 6 stations · 20 raw sources Graphics card 7 stations · 26 raw sources Hearing aid 6 stations · 24 raw sources Heart stent 6 stations · 15 raw sources Hip implant 9 stations · 22 raw sources Indium tin oxide 7 stations · 15 raw sources Inkjet printer 6 stations · 31 raw sources LCD screen 6 stations · 19 raw sources LED 8 stations · 10 raw sources Memory chip 7 stations · 10 raw sources Microchip 8 stations · 15 raw sources Newspaper 6 stations · 19 raw sources OLED screen 6 stations · 16 raw sources Printed circuit board 8 stations · 18 raw sources Silicon wafer 6 stations · 8 raw sources Smartwatch 9 stations · 31 raw sources Television 6 stations · 26 raw sources Wallpaper 7 stations · 22 raw sources Wi-Fi router 7 stations · 27 raw sources

What it looks like on the line

MicrochipDraw circuits with ultraviolet. In the most advanced machines, a laser hits tin droplets about 25 micrometers wide, flying at roughly 70 meters per second, and the resulting plasma emits light at 13.5 nm. Glass and air absorb that light, so mirrors in a vacuum steer it onto the wafer.
Graphics cardFabricate the graphics chip. The GPU is patterned on a silicon wafer, repeating light exposure and etching to build billions of transistors. The wafer is cut into chips that are tested and sorted.
LCD screenPattern transistors on glass. A large sheet of glass is coated with thin films and etched into a grid of thin-film transistors, one for each subpixel, with transparent electrodes of indium tin oxide.
Wi-Fi routerEtch the bare board. Copper layers on a substrate are etched into circuit paths, holes are drilled and plated, and a solder mask and printed labels go on. One maker then laser-engraves a QR code on each board so any flaw can be traced.
Heart stentElectropolish the struts. The cut stent goes into an electrolytic acid solution, and electric current strips metal from its surface. This takes off the rough edges from cutting, since a rough surface in a blood vessel can promote clotting.
Hearing aidPrint the circuit board. A thin flexible board is etched with copper tracks that link every component. It is only a few millimeters across in the smallest models.
MicrochipEtch and implant. A developer washes away the exposed resist. Plasma etching then cuts the pattern into the layer below, or ion implantation embeds dopant atoms in the open areas to change how well silicon conducts.
Memory chipPrint the cell grid. Light patterns a repeating array of cells across each die. A DRAM cell needs only a transistor and a microscopic capacitor, while a static memory cell needs four or six transistors, which is why DRAM packs so densely.
Camera sensorBuild the pixel array. Millions of pixels are patterned on a silicon wafer. Each has a pinned photodiode that collects light as charge and a few transistors to amplify it.
Silicon waferEtch off the damage. A chemical bath dissolves the crystal damage left behind by sawing and grinding.
Compact discMaster the pit pattern. The audio data is encoded and written as a spiral of tiny pits onto a master disc. The master is used to make a metal stamper, the negative of the pit pattern.
Hip implantPolish in acid. In the patent's method, the part sits in an acid bath with current running through it, which strips a thin skin and leaves a bright finish. It is then cleaned ultrasonically.