Semiconductor Testing Tools - Probe Stations

Probe Stations

Probe Stations are one of the most important test equipment in the semiconductor industry and are widely used for precision electrical measurements of complex and high-speed devices, with the aim of ensuring quality and reliability, and reducing R&D time and costs in the device manufacturing process. By working with test instruments,probe station non-compliant chip parameters can be recorded and rejected before entering post-processing, greatly reducing device manufacturing costs. Probe stations are mainly used for wafer testing, chip development and failure analysis in the wafer fabrication process.

Semiconductor test data can be analyzed according to the production management process can be developed into the following three categories: verification system test, wafer test test, package testing. Wafer testing work link we need to use the enterprise network tester and probe table, tester / machine for testing the main functions and performance of the chip, probe table to realize the connection between the chip under test and the tester, through the probe table and the tester with the use of teachers on the wafer on the bare chip design of the social functions and electrical parameters of the test or RF test, you can screen the chip's good, defective product information.

What is the role of the probe table?

A probe bench places electrical, optical or RF probes on a silicon wafer to test the chip/semiconductor device in conjunction with a test instrument/semiconductor test system. These tests can be as simple as a continuity or isolation check or as complex as a full functional test including microcircuits. Tests can be performed before or after cutting the wafer into individual cores. Wafer-level testing allows the manufacturer to test the chip device multiple times during production, which can provide information about which process steps introduced defects into the final product. It also enables manufacturers to test chips prior to packaging, which is important in applications where packaging costs are high relative to device costs. Probe tables can also be used in R&D, product development and failure analysis applications.

How does a probe table work?

test probe can be used to fix a wafer or chip and precisely market the object to be tested. The user of a manual probe table installs the probe arm and probe into a manipulator and uses an electron microscope to place the probe tip into the correct development position on the object to be measured. Once all the probe tips of the company have been set in the correct position by us, it is possible to analyze and test the object to be tested by yourself. For some wafers with chips from multiple countries in China, the platen can be lifted simultaneously between users, the platen separates the probe tip from the chip and the table is then moved to the next chip to find a more precise position using the microscope, the platen is lowered and the next important chip data can be managed effectively for testing. Semi-automated and fully automated probe table system research uses agro-mechanized workbench and machine vision to automate the solution to this world moving teaching process that increases probe table productivity.

Classification of Probe Stations

Based on the type of use and functionality and also based on the mode of operation, probe tables can be categorized into manual probe tables, semi-automatic probe tables and fully automated probe tables.

Manual probe table systems are manually controlled, which means that the wafer table, chuck, platen, microscope and positioner are all moved manually by the user. Therefore, manual probe stations are generally used when there are few devices to measure or few data to collect. An advantage of this type of probe station is that it requires minimal training, is easy to configure the environment and change test environments, and does not require electronics, PCs, or software that involve additional training and setup time.

Semi-automated probe stations are primarily used where precise motion, repeatable contact and large amounts of data are required. Some companies also use semi-automated probe systems for their small production runs. Most of the components of a semi-automatic probe system are similar to a manual probe stage except for the carrier stage and controls. The wafer table is usually programmable, with motion and direction controlled through software and an electronic controller. The software adds many features to the probe station system. The user can move the stage in any direction at any speed via software or a mechanical joystick. The program can set up mappings to match the equipment and can select the equipment to be detected.

Automated Probe Station Systems

Compared to the above two, the fully automated probe stage adds a wafer material handling unit (MHU) and pattern recognition (auto-alignment). It is responsible for transferring and positioning the wafers so that the grains on the wafers come into contact with the probes in sequence and are tested one by one. It can work continuously for 24 hours and is usually used for mass production of chips or with some special requirements such as handling thin wafers and package substrates. Fully automated probe tables are also much more expensive than manual semi-automated probe tables.

What are the important parts of a Probe Table?

Sample Table (Carrier Table) : A device used to position the components of a wafer or chip. It is usually sized according to the size of the wafer and is complemented by a corresponding precision movement positioning function.

Optics: The function of this component is to allow the user to visually magnify and observe the object to be measured so that the probe tip can be accurately aligned and placed on the measurement point of the wafer to be measured. Some use a stereo zoom microscope, some use a digital camera, or both.

Chuck: Having a very flat metal surface, the chuck is used to clamp the object in place, or a vacuum is used to absorb the wafer.

Probe (Probe Card): The chip to be tested requires a test probe connection to establish a connection to the test instrument. Commonly used are DC test probes, coaxial DC test probes, active probes and microwave probes. The probes are inserted into a single probe arm and mounted on a manipulator. The probe tip size and material depends on the size of the feature to be tested and the type of measurement required. The probe tip is in direct contact with the part to be measured and the probe arm should be matched to the probe tip.

Probe fixtures and cable assemblies: Probe fixtures are used to hold probes and connect them to the measurement analyzer. Cable assembly technology is used to improve the transfer, extension of the cable assembly on the probe fixture.

micromanipulators (positioners): Probe stations use manipulators to place probes on the test object, allowing for easy positioning of the probe and quick repair of the probe. They are usually held in place by magnets or vacuum. Once fixed, the manipulator can accurately position the probe tip in the x, y, and z directions and, in some cases, provide an axis of rotation.