Handler or prober and device test adapter

ATE can be used to package components (typically IC "chips") or directly to silicon wafers.Packaged parts use processors to place devices on custom interface boards, while silicon wafers are tested directly using high-precision probes.The ATE system interfaces with a processor or probe to test the DUT.

Encapsulated components with handlers ATE

An ATE system is often interfaced with an automated placement tool called a "handler" that physically places the device under test (DUT) on the interface test adapter (ITA) so that the device can make measurements on it.There may also be an Interface Test Adapter (ITA), a device that merely establishes the electrical connection between the ATE and the device under test (also known as the Unit Under Test or UUT), but it may also contain an additional circuit to accommodate the ATE between the signal and the DUT, and have the physical facility to mount the DUT.Finally, use a socket to bridge the connection between the ITA and the DUT.Sockets must withstand the rigors of the production floor and therefore often require frequent replacement.

Simple electrical interface diagram: ATE → ITA → DUT (package) ← Handler

Silicon wafer ATE with probers 

Wafer-based ATE typically uses a device called a prober that moves across the silicon wafer to test the device.

Simple electrical interface diagram: ATE → Prober → Wafer (DUT)

Multi-site

One way to improve test time is to test multiple devices at once.ATE systems can now support having multiple "sites" where the ATE resources are shared by each site.Some resources can be used in parallel, others must be serialized to each DUT.

Programming ATE

ATE computers control ATE devices through standard and proprietary application programming interfaces (APIs) using modern computer languages such as C, C++, Java, Python, LabVIEW, or Smalltalk and additional statements.There are also specialized computer languages such as the Abbreviated Test Language for All Systems (ATLAS).Automatic test equipment can also be automated using a test execution engine such as NI's TestStand.Automatic test pattern generation is sometimes used to help design a series of tests.

Test data (STDF)

Many ATE platforms used in the semiconductor industry output data using the Standard Test Data Format (STDF)

Diagnosis

Automatic test equipment diagnostics are part of ATE testing to identify faulty components. ATE tests perform two basic functions.The first is to test whether the device under test is working properly.The second is to diagnose the cause when the DUT is not working properly.The diagnostic portion can be the most difficult and expensive part of the test.ATE typically reduces failures to clusters or fuzzy groups of components.One way to help reduce these ambiguous groups is to add mock signature analysis tests to the ATE system. Diagnosis is often aided by the use of flying probe tests.

Test equipment switching

Adding a high-speed switching system to the configuration of a test system enables faster and more economical testing of multiple devices, with the aim of reducing test errors and costs.Designing a switch configuration for a test system requires an understanding of the signals to be switched and the tests to be performed, as well as the available switch hardware form factors.

Test equipment platforms

Several modular electronic instrumentation platforms are currently commonly used to configure automated electronic test and measurement systems.These systems are widely used for incoming inspection, quality assurance and production testing of electronic devices and subassemblies.Industry standard communication interfaces connect signal sources to measurement instruments in "rack stack" or chassis/mainframe based systems, usually under the control of a custom software application running on an external PC.

GPIB/IEEE-488

General Purpose Interface Bus (GPIB) is an IEEE-488 (standard developed by the Institute of Electrical and Electronics Engineers) standard parallel interface for connecting sensors and programmable instruments to computers.GPIB is a digital 8-bit parallel communication interface capable of data transfers in excess of 8 Mbytes/s.It allows up to 14 instruments to be daisy-chained to the system controller using a 24-pin connector.It is one of the most common I/O interfaces in instruments and is designed for instrument control applications.The IEEE-488 specification standardizes the bus and defines its electrical, mechanical, and functional specifications, as well as its basic software communication rules.GPIB is best suited for applications in industrial environments that require a robust connection for instrument control.The original GPIB standard was developed in the late 1960s by Hewlett-Packard to connect and control the programmable instruments the company manufactured.The introduction of digital controllers and programmable test equipment created a need for a standard, high-speed interface for communication between instruments and controllers from various vendors.In 1975, the IEEE published ANSI/IEEE Standard 488-1975, IEEE Standard Digital Interface for Programmable Instrumentation, which contained the electrical, mechanical, and functional specifications of an interfacing system. This standard was subsequently revised in 1978 (IEEE-488.1) and 1990 (IEEE-488.2). The IEEE 488.2 specification includes the Standard Commands for Programmable Instrumentation (SCPI), which define specific commands that each instrument class must obey. SCPI ensures compatibility and configurability among these instruments.

The IEEE-488 bus has long been popular because it is simple to use and takes advantage of a large selection of programmable instruments and stimuli. Large systems, however, have the following limitations:

Driver fanout capacity limits the system to 14 devices plus a controller.

Cable length limits the controller-device distance to two meters per device or 20 meters total, whichever is less.This imposes transmission problems on systems spread out in a room or on systems that require remote measurements.

Primary addresses limit the system to 30 devices with primary addresses. Modern instruments rarely use secondary addresses so this puts a 30-device limit on system size.

LAN eXtensions for Instrumentation (LXI)

The LXI Standard defines the communication protocols for instrumentation and data acquisition systems using Ethernet.These systems are based on small, modular instruments, using low-cost, open-standard LAN (Ethernet).LXI-compliant instruments offer the size and integration advantages of modular instruments without the cost and form factor constraints of card-cage architectures. Through the use of Ethernet communications, the LXI Standard allows for flexible packaging, high-speed I/O, and standardized use of LAN connectivity in a broad range of commercial, industrial, aerospace, and military applications.Every LXI-compliant instrument includes an Interchangeable Virtual Instrument (IVI) driver to simplify communication with non-LXI instruments, so LXI-compliant devices can communicate with devices that are not themselves LXI compliant (i.e., instruments that employ GPIB, VXI, PXI, etc.).This simplifies building and operating hybrid configurations of instruments.

LXI instruments sometimes employ scripting using embedded test script processors for configuring test and measurement applications.Script-based instruments provide architectural flexibility, improved performance, and lower cost for many applications. Scripting enhances the benefits of LXI instruments, and LXI offers features that both enable and enhance scripting.Although the current LXI standards for instrumentation do not require that instruments be programmable or implement scripting, several features in the LXI specification anticipate programmable instruments and provide useful functionality that enhances scripting's capabilities on LXI-compliant instruments.

VME eXtensions for Instrumentation (VXI)

The VXI bus architecture is an open standard platform for automated testing based on the VME bus.Introduced in 1987, VXI uses all Eurocard form factors and adds trigger lines, local bus, and other features suitable for measurement applications.VXI systems are based on mainframes or chassis with up to 13 slots into which various VXI instrumentation modules can be installed.The chassis also provides all power and cooling requirements for the chassis and the instruments it contains.VXI bus modules are typically 6U high.

PCI Extensions for Instruments (PXI)

PXI is a peripheral bus dedicated to data acquisition and real-time control systems. Introduced in 1997, PXI uses the CompactPCI 3U and 6U form factors and adds trigger lines, a local bus, and other features suitable for measurement applications.The PXI hardware and software specifications are developed and maintained by the PXI Systems Alliance. More than 50 manufacturers worldwide produce PXI hardware.