Macrocell:
A semiconductor building block containing a relatively complex electronic function that can be combined through CAD with other cells to perform a complex function with less design effort than a complete "ground-up" design.

Majority carrier:
The mobile charge carrier (hole or electron) that predominates in a semiconductor material. When a channel is created within the silicon, the channel will normally result from a change of majority carrier.

Mask:
A patterned screen of any of several materials used to expose selected areas of a semiconductor covered with a light-sensitive photoresist to polymerizing light during the fabrication process.

Mechanical shock:
An impact-type shock test to stress die attach, wire bonds, and seal integrity, normally performed on a sample basis.

Metal gate:
An MOS process fabricated with a metal (usually aluminum) as the gate electrode.

Microcrack:
A very small crack within the metal or other material of a semiconductor device, typically not detectable using optical magnification. In the metallization area, microcracks most typically occur at contact steps. Microcracks can lead to discontinuities in the circuitry.

Micron(µ):
A unit of length. 106µ= 1 m (meter). [Note: µ as a symbol of length should not be confused with µ used as a prefix to indicate microunits, such as µA (microamps) or µV microvolts). A micron is one micrometer.]

Mixed Signal ASIC
An Application Specific Integrated Circuit (ASIC), that contains both analog and digital circuits

Moisture resistance:
Subjection of sample devices to a cycle of high humidity and temperature stresses to determine the ability of these devices to survive under severe environmental conditions. This is normally performed on a sample basis with 10 cycles of 24-hour duration.

Molded device:
A device which is completely encapsulated in epoxy or an alternate molding compound, that is, with no internal cavity.

Monolithic device:
A device whose circuitry is completed contained on a single die or chip.

MSI:
Medium Scale Integratio - MSI devices are generally accepted to be those that contain 12 or more gate equivalents, but less than 100.

MSL
Moisture Sensitivity Level relates to the packaging and handling precautions for some semiconductors. The MSL is an electronic standard for the time period in which a moisture sensitive device can be exposed to ambient room conditions (approximately 30°C/60%RH).

MTBF:
Mean Time Between Failure - The average number of operating hours after a device has failed that would pass before the next device failure would be expected to occur.