How are wafers tested?
Why do we still test wafers?
Every wafer and silicon die are tested so that our customers can be assured they will have a fully functional semiconductor when they are ready to use it. It is a great assistance in the manufacturing process as well, because if one is found to be non-effective, it won't go through the final steps.Oct 30, 2020
What is wafer probing process?
Wafer probing is the process of electrically testing each die on a wafer. ... 1), which holds a wafer on a stable platform and drops a set of precision point needles on designated probe pads on the die. The probe system is usually connected to an automatic test equipment (ATE) using special interfacing hardware (see Fig.
What much testing is being conducted on a piece of wafer?
Wafer sort (or wafer test), is a part of the testing process performed on silicon wafers. Wafer sort is a simple electrical test, that is performed on a silicon die while it's in a wafer form. Wafer sort's main purpose is to identify the non-functional dies and thereby avoiding assembly of those dies into packages.
What is semiconductor final test?
Normally, IC testing is conducted at two levels: the wafer test (also called die sort or probe test) that tests wafers, and the package test (also called final test) after packaging. Wafer testing uses a prober and a probe card, while package testing uses a handler and a test socket, together with a tester.
What is a test chip?
The test chips are used to validate that the IPs are properly designed and meet the functional specifications of the protocols. They also are used to validate if sufficient margins are designed into the IP to mitigate variances due to process tolerances.Jun 27, 2019
What is EWS semiconductor?
ElectroMagnetic Wafer Sort (EMWS) is an evolution of Electrical Wafer Sort (EWS), the last stage of wafer fabrication before assembly and test of the final packaged products. At this stage in the manufacturing cycle, the processed wafer contains an array of identical circuits called die.Dec 14, 2011
What is wafer map?
A wafer map identifies the locations of defective integrated circuits (chips) on a silicon wafer and provides important spatial information. The wafer yield is a useful measure of the process quality, but other features are necessary to account for.
What is wafer sorter?
Wafer sort is a simple electrical test, that is perform on a silicon die while it's in a wafer form. Wafer sort's main purpose is to identify the non-functional dies and thereby avoiding assembly of those dies into packages.
How wafers are fabricated?
The silicon wafers start out blank and pure. ... First, photoresist patterns are photo-masked in micrometer detail onto the wafers' surface. The wafers are then exposed to short-wave ultraviolet light and the unexposed areas are thus etched away and cleaned.
What is probing in semiconductor?
A probe card is an interface between an electronic test system and a semiconductor wafer. ... Its purpose is to provide an electrical path between the test system and the circuits on the wafer, thereby permitting the testing and validation of the circuits at the wafer level, usually before they are diced and packaged.
Why do we test IC?
The test of the IC is intended to insure that all common pins are connected to the same network of pins, independent pins make a connection to the die, and there are no shorted pins. The continuity test verifies the common pins are connected and that no pins are shorted.Apr 29, 2014
What is IC test socket?
An IC socket is used in the final test. It plays the crucial role of connecting the device and the tester, just as a probe card does in the wafer test (see the figure below). ... Although these two types are both generally referred to as IC sockets, the required performance varies depending on the difference in use.
What is IC test handler?
Special sophisticated electronic systems called Automatic Test Equipment (ATE or just Testers) and robotic electromechanical machinery called IC Test Handlers are employed to provide high quality and throughput. ...
How does a wafer testing machine work?
- A wafer prober is a machine ( Automatic test equipment) used to test integrated circuits . For electrical testing a set of microscopic contacts or probes called a probe card are held in place whilst the wafer, vacuum-mounted on a wafer chuck, is moved into electrical contact.
What is a wafer probe test?
- A wafer prober is a system used for electrical testing of wafers in the semiconductor development and manufacturing process. In an electrical test, test signals from a measuring instrument or tester are transmitted to individual devices on a wafer via probe needles or a probe card and the signals are then returned from the device.
What is wafer thinning?
- Wafer thinning is the process of removing material from the backside of a wafer to a desired final target thickness.