Wafer Testing
Silicon Wafer Cz/Fz
2-6" Si wafer , 100, 111, 110, intrinsic, heavily doped and thin wafer available.
www.semiwafer.com
Silicon Wafers
Learn more about Silicon Wafers.
topicriver.com
Cibel
Probe cards & test interface nude pcb manufacturer. Worldwide & fast.
www.test-pcb.com
Better, Cheaper Faster Probing Solutions
For your wafer level test requirements Semiprobe offers highly reliable solutions at affordable prices.
www.semiprobe.com
Wafer Testing
American Semiconductor, Inc. can convert your designs to our standard processes, install your existing process in our wafer fab or provide production of customer specified processes.
www.americansemi.com
Portable Hand-Held PC Microscope USB
Compact Design, 10x to 200x Mag. Capture Stills Images/Video. USB Int.
www.pcgears.com
Test Wafer Distributor
We supply customized silicon wafers in a variety of designs & grades.
www.svmi.com
Wafer testing - Wikipedia, the free encyclopedia
Wafer testing is a step performed during semiconductor device fabrication. ... For this reason, one might think that wafer testing is an unnecessary, redundant step. ...
en.wikipedia.org
SKW Associates, Inc.
www.testwafer.com
High-Throughput Microwave Probing
Abstract This paper surveys the state of RFIC wafer testing ... performance screen at the wafer level, followed by only. continuity testing after packaging. ...
thor.inemi.org
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In microelectronics, a wafer is a thin slice of semiconducting material, such as a silicon crystal, upon which microcircuits are constructed by doping (semiconductors) (for example, diffusion or ion implantation), chemical etching, and Thin-film deposition of various materials. Wafers are thus of key importance in the Semiconductor fabrication of semiconductor devices such as integrated circuits.
They are made in various sizes ranging from 1 inch (25.4 mm) to 11.8 inches (300 mm), and thicknesses of the orders of magnitude 0.5 mm. Generally, they are cut from a boule (crystal) of semiconductor using a diamond blade or diamond wire, then Chemical-mechanical planarization on one or both faces.
and crystallography orientation. Red represents material that has been removed.Wafers under 200 mm generally have flats indicating crystallography planes of high symmetry (usually the {110} face) and, in old-fashioned wafers (those below about 100 mm diameter), the wafer's orientation and doping type (see illustration for conventions). Modern wafers use a notch to convey this information, in order to waste less material .
Orientation is important since many of a single crystal's structural and electronic properties are highly anisotropic. For instance, wafer cleavage (crystal) typically occurs only in a few well-defined directions. Scoring the wafer along cleavage planes allows it to be easily diced into individual chips ("Die (integrated circuit)s") so that the billions of individual Electronic component on an average wafer can be separated into many individual circuits.
Wafer testing Wafer testing is a step performed during Fabrication (semiconductor). During this step, performed before a wafer is sent to die preparation, all individual integrated circuits that are present on the wafer are tested for functional defects by applying special test patterns to them. The wafer testing is performed by a piece of test equipment called a wafer prober. The process of wafer testing can be referred to in several ways: Wafer Sort (WS), Wafer Final Test (WFT), Electronic Die Sort (EDS) and Circuit Probe (CP) are probably the most common.
When all test patterns pass for a specific die, its position is remembered for later use during integrated circuit packaging. Sometimes a die has internal spare resources available for repairing (i.e. flash memory IC); if it does not pass some test patterns these spare resources can be used. If redundancy of failed die is not possible the die is considered faulty and is thrown away. Non-passing circuits are typically marked with a small dot of ink in the middle of the die, or the information of passing/non-passing is stored in a file, named a wafermap. This map categorizes the passing and non-passing dies by making use of bins. A bin is then defined as a good or bad die. This wafermap is then send by a computer network or floppy disk to the die attachment process which then only picks up the passing circuits by selecting the bin number of good dies. The process where no ink dot is used to mark the bad dies is named substrate mapping. When ink dots are used, vision systems on subsequent die handling equipment can disqualify the die by recognizing the ink dot.
In some very specific cases, a die that passes some but not all test patterns can still be used as a product, typically with limited functionality. The most common example of this is a microprocessor for which only one part of the on-die CPU cache memory is functional. In this case, the processor can sometimes still be sold as a lower cost part with a smaller amount of memory and thus lower performance. Additionally when bad dies have has been identified, the die from the bad bin can be used by production personnel for assembly line setup.
The contents of all test patterns and the sequence by which they are applied to an integrated circuit are called the test program.
After IC packaging, a packaged chip will be tested again during the Semiconductor fabrication#Device Test phase, usually with the same or very similar test patterns. For this reason, one might think that wafer testing is an unnecessary, redundant step. In reality this is not usually the case, since the removal of defective dies saves the considerable cost of packaging faulty devices. However, when the yield is so high that wafer testing is more expensive than the packaging cost of defect devices, the wafer testing step can be skipped altogether and dies will undergo blind assembly.
See also
- Cobilt
- Wafer prober
Sources