How Microchips are made

you may not realize it but we're surrounded by arguably the greatest most revolutionary invention of the last 50 years it's in TVs stereos watches cars phones traffic lights and pretty well every appliance in your kitchen in fact these days if a device uses electricity it probably uses one the tiny gizmo in question is of course the silicon chip making these extraordinary miniature electronic brains is one of the most complex manufacturing tasks ever attempted so how do they do it in Texas USA polled to big stuff big cows big boots big hats big moustaches but Texas is also the birthplace of a miniaturized miracle the silicon chip and here in Sherman 30 kilometers north of Dallas is the M EMC fabrication facility here in this strange futuristic looking plant they produce silicon wafers which are the basis for all modern microchips silicon has special properties because it's what's called a semiconductor that means depending on how its treated silicon can either conduct or block the flow of electricity it's this property that makes it perfect for supporting the millions of tiny transistors necessary for a modern computer chip the trouble is because these transistors are so incredibly small the silicon base on which they rest needs to be absolutely perfect it took decades to discover a way to produce silicon with a perfect mono crystalline structure they begin with raw poly silicon or poly and heat it to 1420 degrees Celsius inside a special sealed furnace which has been purged with argon gas to eliminate any air the resulting Lake of molten silicon is then spun in a crucible and a silicon seed crystal roughly the size and shape of a pencil is lowered into it while spinning in the opposite direction as the molten polysilicon is allowed to cool the seed crystal is slowly withdrawn at around one and a half millimeters a minute the result is a single silicon crystal weighing around 200 kilos and with a diameter of around 200 millimeters the crystal is so strong its entire weight can be supported by a single thread just three millimeters across but it is brittle and it must now be cut down to size without shattering so after testing with chemicals and x-rays to check its purity and molecular orientation it's fed to a silicon salami slicer this 10-ton wire saw uses a fast-moving web of ultra-thin wire to produce wafers of silicon that are just two thirds of a millimeter thick and ninety-nine point nine nine nine nine nine nine nine nine percent pure but once cut there are microscopic marks left on the wafer surface so it's time for a buffer using a process called lapping but even after a twirl in this high-powered polisher they're still not smooth enough so they're then given yet another buff using a chemical process the result is wafers of silicon with a surface roughness of less than 0.1 billion billionth of a meter buffed to a sheen they're now ready for etching with the circuit design packing millions of transistors onto these tiny wafers is the job of chip manufacturers like Texas Instruments back in 1958 the inventor of the integrated circuit Jack Kilby managed to squeeze a single transistor onto his design these days the latest generation use almost a billion and according to Moore's law that number doubles every two years but of course the more they try and pack into the design the smaller each transistor needs to get there are over a quarter billion transistors in this design someone has to shrink them down to this working at this microscopic scale exposes the chip makers to a major problem when a transistor is only one ten thousandth of a millimeter across the smallest particle of dust is enough to cause an electronic trainwreck so before staff like Dane Baily set to work in the fab it's on with the bunny suit wafer fab stands for wafer fabrication we build the chips here we start with the bare silicon wafer we've run through a multitude of different processing steps for our general product that we make here a DSP typically takes on the order of about 1500 individual processing steps from start to finish with an area of just under 18,000 square meters the PHAB is a class 1 cleanroom thanks to 12,000 tons of air conditioning equipment the air is a thousand times cleaner than a hospital operating theater there is actually less than 100 particles per cubic foot of air as few as one particle landing on a critical area can kill a chip to give you an idea how clean this room is walking alone produces five million particles every minute so to avoid contamination from the inadvertently dusty staff front opening unified pods or foots ferry packets of wafers through the intricate process of component construction the key problem is miniaturizing the complex designs and imprinting them on the wafers it's done through a process known as photolithography first the wafer is coated with photosensitive chemicals which harden when exposed to UV light in sealed dark rooms light is shone through an image of the design then through a miniaturizing lens and onto the coated wafer when the chemical is washed off the design remains just like a developed photographic image but in order to pack all the components onto the wafer they're built up layer by layer like floors in a miniature skyscraper so to complete the job the Fuchs cycle the wafers up to 40 times repeating the photo etching process for each new layer some layers are cooked some blasted with ionized plasma some bathed in metals each different type of treatment changes the properties for that layer and slowly forms part of the jigsaw making up the chips design the finished sheets of silicon wafer carry up to 1000 individual microchips and over 4 thousand billion circuit elements all the remains is to slice and dice and the journey from sand to circuit board is complete what was once a worthless pile of sand can now change hands for more than $17,000 a gram and calculate PI to 1000 decimal places in the blink of an eye metaphysical poet William Blake reckoned he could see a world in a grain of sand but if he were to look again now he would surely be even more amazed to discover a billion tiny transistors

Channel: Linas K

Views: 1,088,424

Keywords: silicon, texas instruments

Id: F2KcZGwntgg

Length: 8min 53sec (533 seconds)

Published: Wed Oct 13 2010