Microchip Assembly Process: Birth of a microchip, “bunny suits” and more!
The process of creating semiconductor microchips goes far beyond the engineers who design the part, but also the production of substrates, the silicon ingots and wafers, the wafer processing machinery, and the packaging of the device itself (encapsulation) and the packaging to protect, carry and store the finished device so that it can be safely placed on circuit boards. The supporting careers for all of these steps are immense, are world wide, and everyone plays a critical role!
If one step is excluded on one component in one subsystem, no smartphones, automobiles or computers could be created.
Circuit Board Assembly Process: The real SOIC and SOT go through a Surface Mount Assembly process.
Function specific microchips are assembled on Printed Circuit Boards (PCB) to create high level systems like smartphones and computers.
Tape and Reel Packaging
Finished microchips are stored and shipped in layers of film on reels, like classic movie films.
Take a look at one of millions of actual packaging specifications for one actual SOIC device here. Many marketing, sales, drawing, writing, materials specialists and management are required to make sure all of these specifications match up in the real world.
Microchip Packaging – Encapsulation
Semiconductor chips are placed on metal leadframes (legs) and then filled with plastic to form the bodies.
Pick and Place
SOIC is frightened when the Surface Mount placement machine “chunk, chunk, chunk’s” it’s way toward him. But as you’ll see in this video of a state-of-the-art “pick-and-place” machine, this fast and gentle robot carries the parts with the grace of a ballet dancer!
Infrared Reflow Process
Making all of the thousands of connections between the chips at once!
Here is a great animation of that oven, (you might recognize it correctly as an advanced industrial kitchen toaster oven) Starting at 1:25 in the video, you’ll see the actual “SOIC & SOT View” you can imagine as they are “eaten” by the big scary oven. And in the bottom left “zoom” window you can see an excellent capture of a SOIC or SOT “leg” melting the microsphere “grey goop” of solder into “warm bubbly” molten solder during the warming-cooling profile of the oven.
This is not “glue” although it looks like a paste and is called “solder paste.” It is actually millions of tiny soft metal balls, as small as dust, suspended in a gel that keeps the metal pure and clean as it melts and flows.
Inspection and Automated Test
While testing is only briefly mentioned in the book, it is a critical element of production to catch assembly errors as soon as possible. As very expensive systems are assembled, the further down the process the mistakes go, the harder and more expensive they are to correct.
After assembly, the boards are placed on a “bed of nails” tester that has “pogo pins” which touch critical test points in the circuits, and the board is quickly powered up and runs a few basic tests to see if everything is there.
Terms referenced in the series
ASSEMBLY: the process of combining devices and components into a higher-level system
BIT: single binary value of ‘1’ or ‘0’
BOARD: a flat piece of copper-plated fibreglass or plastic on which components are placed and soldered to to form connections.
CHIP: a circuit printed in aluminum, copper or gold on a tiny piece of silicon (see integrated circuit)
CIRCUIT: a set of paths that electric currents travel trhough, usually including the source of electric energy
CODE: a set of numbers, letters, or signals used in electronics to represent data, instructions, words or images, etc.
COMPUTER: electronic machine that stores information and follows instructions to process it
DEVELOPMENT: the process of combining simpler components into something more advanced, such as connecting chips in circuits to make a computer
DEVICES: an individual component that performs a specific set of tasks or functions
ELECTRICAL: using or carrying currents produced by voltages between circuit nodes (Example
ELECTRICITY: the flow (AC or DC current) or accumulation (static electricity) of electrons
ELECTRONIC: similar to electrical, but usually more integrated and complex circuits and functions (Example
EMBEDDED: a device that performs a critical function in a larger unit (Example
ENGINEER: someone applies scientific principles in an elegant manner to build roads, bridges, machines etc.
ESD: Electro-Static Discharge – an event that occurs when electrostatic charge is transferred as a current through a conductor (Example
FORTRAN: an early programming language used for science and engineering
FUZZY: unclear or lacking specifics; a type of calculation logic that attempts to mimic complex human decisions
GREY GOOP: (see also Solder Paste)
INFORMATION: a meaningful arrangement or sequence of data
INTEGRATED CIRCUIT: a chip or device that incorporates multiple functions or data processing elements
MAINFRAME: a large computer that can be used by many people, originally named after the early floor-standing
MANUFACTURING: process of assembling devices or systems into more complex devices or systems using machines
MEMORY: a device or subsystem that stores information, usually in a large array of cells which store bits
MICROCHIPS: a very small piece of silicon containing circuits designed to perform one or more functions
NETWORK: a system of interconnected systems that allows communication between them
NOISE: to people, usually an annoying sound, in electronics, spurious signals that interfere with information integrity
“NUTS-AND-VOLTS”: a play on words used in SOIC and SOT, and a long running electronics magazine
PATENTS: a temporary initial monopoly for an inventor to make and sell a new product
PICK AND PLACE: an automated process of removing devices from their packaging and placing them in the right place on a circuit board
PLASTIC: the quality of being easily made into any shape
PRINTER: a machine connected to a computer that puts documents from the computer onto paper
REEL: a round object, similar to a movie film reel, onto which devices in regularly spaced plastic tape carriers are wound
REFLOW: the method of applying heat to solder until it liquifies and flows between connections, via hot air convection or infrared radiation
SCANNING: in which a machine produces a picture of the inside of your body
SCIENCE: knowledge about the physical world, especially based on examining, testing, and validation of hypothesis
SEMICONDUCTOR: a crystalline substance such as silicon, that allows electric charges to be modulated, stored, switched or impeded
SOFTWARE: sets of instructions that tell a computer what to do (see also Code)
SOIC: Small Outline Integrated Circuit, a specific standard microchip encapsulation packaging shape
SOLDER: a soft metal, historically a mixture of lead, tin and antimony, which can be melted and used to fasten together two metal surfaces, wires etc.
SOLDER PASTE: a mixture of flux and microspheres of solder which are applied to contact areas, either by hand or silkscreen in preparation for device placement and reflow
SOT: Small Outline Transistor, a specific standard microchip encapsulation packaging shape with 3 or more contacts
SYSTEM: a group of related components assembled as a whole for a particular function
TECHNOLOGY: machines, equipment, and ways of working that are based on science
TEST: to measure a device’s or system’s functionality by applying multiple input values and verifying proper output responses
TRANSISTOR: a basic semiconductor element that controls the flow of electricity in one path by the signal applied to another