VIDEO TRANSCRIPT

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 much  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 ?   Texas, USA home to big stuff …big cows, big boots, big hats, big moustaches but Texas  is also the birthplace of a miniaturised miracle: the silicon chip and here in Sherman, 20 miles north of Dallas is the  MC fabrication facility.  In this strange futuristic-looking plant, they produce silicon wafers which are  the basis for all modern micro chips.  Silicon has special properties because  it’s what’s called a semiconductor… that  means that depending on how its treated, silicon can either conduct or block the  flow of electricity. It’s this property that makes it ideal  for supporting the millions of tiny transistors necessary for a modern computer chip but because these  transistors are so incredibly small the  silicon based on which they rest needs  to be absolutely flawless. It took decades to perfect the process of producing silicon with a perfect mono crystalline structure. They begin with  raw polysilicon or poly and heat it to over 2,500 degrees Fahrenheit 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it while  spinning in the opposite direction as the molten polysilicon is allowed to cool the seed crystal is slowly  withdrawn at around one and a half  millimeters a minute.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 440 pounds 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. 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  99.999 percent pure.  Once cut there are microscopic marks  left on the wafer surface so it’s time  for a buffing using a process called  lapping after a twirl in this  high-powered polisher. They are still not  smooth enough so they’re given yet  another buff using a chemical process  the result is wafers of silicon with a  surface roughness of less than one  millionth of a millimeter buffed machine  they’re finally ready for etching with  this circuit design coming up.  How do they eliminate the biggest enemy  of manufacturing in a microscopic  environment:  the common dust particle?  Find out next on “How do they do it” !

Packing millions of transistors on to  these tiny silicon 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 uses almost a billion and  according to Moore’s law that number  doubles every two years. 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  chipmaker’s 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 train wreck so before staff  members like Dane Bailey set to work in  the fab it’s on with the bunny soup for  our general product that we make here at  DSP typically takes on the order of  about 1,500 individual processing steps  from start to finish  with an area of just under 190 4,000  square feet the fab is a class 1 clean  room thanks to 12,000 tons of air  conditioning equipment  the air is 1000 times cleaner than a  hospital operating room  there’s actually less than 100 particles  per square foot of air.  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 foods transport  packets of wafers through the intricate  process of component construction  the key problem is miniaturizing the  complex designs and imprinting them onto  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  groans 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 are built up layer  by layer like floors in a miniature  skyscraper. To complete the job the folks 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 1,000 individual micro chips  and billions and billions of circuit  elements all that 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  nearly seven hundred dollars an ounce  and calculate pi to 1000 decimal places  in the blink of an eye.  Metaphysical poet William Blake reckoned  he could see the world in a grain of  sand but if he were to look again today  he would surely be more amazed to  discover a billion tiny transistors.