wafer


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wafer

1. Christianity a thin disc of unleavened bread used in the Eucharist as celebrated by the Western Church
2. Pharmacol an envelope of rice paper enclosing a medicament
3. Electronics a large single crystal of semiconductor material, such as silicon, on which numerous integrated circuits are manufactured and then separated

wafer

[′wā·fər]
(electronics)
A thin semiconductor slice on which matrices of microcircuits can be fabricated, or which can be cut into individual dice for fabricating single transistors and diodes.
(engineering)
A flat element for a process unit, as in a series of stacked filter elements.

wafer

(1) A small magnetic tape cartridge in the early 1980s. See Stringy Floppy.

(2) The base unit of chip making. A wafer is a slice taken from a salami-like silicon crystal ingot up to 300mm (11.8") in diameter. The larger the wafer, the more chips produced in a single production pass, which comprises a series of photomasking, etching and implantation steps. Wafers are approximately 1/30th of an inch thick; however, the actual layers of transistors that make up the active circuitry are only a few microns deep (see active area).

Wafers started out from one to three inches in diameter. Then came 100mm ingots (3.9"), followed by 125mm (4.9"), 150mm (5.9"), 200mm (7.9") and 300mm (11.8"). The much larger 450mm (17.7") wafer has yet to be produced in large quantities due to the huge investment in new machinery. See chip, chip manufacturing, transistor and wafer scale integration.


The Boule Is Sliced
The silicon ingot, which is known as a "boule," is sliced into wafers. (Image courtesy of IBM.)







Different Sizes
From top to bottom, the wafers are 150, 200 and 300mm (5.9", 7.9" and 11.8") in diameter. (Images from top to bottom courtesy of Texas Instruments, Inc., Advanced Micro Devices, Inc. and Intel Corporation.).


Different Sizes
From top to bottom, the wafers are 150, 200 and 300mm (5.9", 7.9" and 11.8") in diameter. (Images from top to bottom courtesy of Texas Instruments, Inc., Advanced Micro Devices, Inc. and Intel Corporation.).


Different Sizes
From top to bottom, the wafers are 150, 200 and 300mm (5.9", 7.9" and 11.8") in diameter. (Images from top to bottom courtesy of Texas Instruments, Inc., Advanced Micro Devices, Inc. and Intel Corporation.).







Heating the Wafers
The red glow comes from a furnace that reaches 1000 degrees centigrade. The semiconductor wafers are baked in the oven to prepare them for the chip-making process. (Image courtesy of Intel Corporation.)
References in periodicals archive ?
Intel and its rivals have been plotting a transition to 450-mm wafers for many years, and they've been pushing tool makers like ASML to provide the equipment.
Rear side passivation: While nearly all wafers have a passivated emitter, it is most often on the front facing side of the wafer.
Hersey said Evergreen Solar's wafers use less silicon than other brands - the average wafer uses 6 grams per watt while Evergreen Solar uses 3.9 grams per watt, she said.
Three process parameters are chosen to study their effects and interactions: the rotational speed of the grinding wheel, the rotational speed of the wafer and the federate of grinding wheel towards the wafer.
The EVG systems augment Nemotek's class 10 cleanroom, which already houses several EVG tools, including an EVG6200 bond aligner, a fully automated IQ Aligner UV-NIL system, an EVG520IS wafer bonder, and an EVG40NT metrology system.
The framework supply agreements are recognition of our efforts in strengthening R&D and enhancing production knowhow in producing high quality, large sized wafers that offer superior conversion efficiencies.
"The signing of these wafer supply contracts further demonstrates continuing strong demand for our quality wafer products," said Xianshou Li, ReneSola's chief executive officer.
In line with the expansion of silicon wafer production, Shin-Etsu Handotai will launch silicon ingot production at its Takefu plant in Fukui Prefecture and boost ingot output at its Shirakawa and Washington plants.
Next, the team cut up the wafers to yield laser chips in which an applied voltage makes the indium phosphide layer produce light.
The outlook for Wafer at his February 2000 hearing seemed especially bleak in light of what had happened to the four Tulia defendants who had already been tried.
The company operates two advanced twelveinch wafer fabs, five eight-inch wafer fabs and one six-inch wafer fab.
The proprietary Gliadel wafer contains a precise amount of the chemotherapeutic drug carmustine.