Foundry (electronics)

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This article is about the factory in which integrated circuits are made. For other uses of the term foundry see foundry (disambiguation).

In the microelectronics industry, a foundry (also called a fab for fabrication plant) is a factory where devices like integrated circuits are manufactured. When the term "Foundry" is applied to a fab, it means that there are many devices being made at that fab for one or more customers. A fab that only has one product, or just one customer is generally not called a foundry.

Foundries require many expensive devices to function. Estimates put the cost of building a new foundry over one billion US Dollars.

The central part of a foundry is the clean room, an area where the environment is controlled to eliminate all dust, since even a single speck can ruin a microcircuit, which has features much smaller than dust. The clean room must also be dampened against vibration.

The clean room also contains the steppers for photolithography, etching, cleaning, doping and dicing machines. All these devices are extremely precise and thus extremely expensive.

[edit] Evolution

Typically an advance in chip-making technology requires a completely new foundry to be built. In the past, the equipment to outfit a foundry was not terribly expensive and there were a huge number of smaller fabs producing low-volume chips. However, the cost of the most up-to-date equipment has since grown to the point where a new foundry can cost on the order of two billion dollars.

Another side effect of the cost has been the challenge to make use of older fabs. For many companies these older fabs are useful for producing designs for unique markets, such as embedded processors, flash memory, and microcontrollers. However for companies with more limited product lines, it's often best to either rent out the fab, or close it entirely.

There has been a trend to produce ever larger wafers, so each process step is being performed on more and more chips at once. Unfortunately it is impossible (or at least impractical) to retrofit machinery to handle larger wafers. This is not to say that foundries using smaller wafers are necessarily obsolete, older foundries can be cheaper to operate, have higher yields for simple chips and still be productive.