The Barth Pulse Curve Tracer, Model 4002 TLP is the first commercial TLP (Transmission Line Pulse) tester to be produced since this method of testing was developed 18 years ago. TLP testing is used as a pulse type curve tracer to measure the current-voltage characteristics designed into ESD (Electro-Static Discharge) protection circuitry. This new hardware was designed to fit the needs of present users of TLP who have requested a commercial TLP test system that is more repeatable and produces faster test results than homemade systems.
Barth 4002 TLP
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This "classical" TLP tester has been produced by test equipment engineers who have been designing state-of-the-art fast-pulse high voltage measurement hardware for over 40 years.
Special Barth wide bandwidth pulse current and voltage sensors provide a new standard of measurement capability for ESD test equipment. The complete system has been built with special attention to minimize the losses in the test circuitry and the coaxial cable connections. This provides low internal resistance at the Device Under Test (DUT), for high accuracy measurements.
Clean pulse generation and precision measurements combined with computer control, provides repeatable and fast data collection with minimal operator intervention. The operator chooses the test parameters and then selects the start button to run the test. Barth Electronics has combined these capabilities into one complete system that is now available for your TLP testing. This test system can be relied upon to produce consistent TLP data on a day to day basis. Because of the built-in accuracy, TLP measurements can now be standardized throughout the semiconductor industry.
Components of the Barth Pulse Curve Tracer, Model 4002 TLP consist of a Tektronix 500 MHz digitizing oscilloscope, the Barth Model 40021 pulse generator and control box, a Stanford Research Systems Model PS350 HV source, a Keithley Model 487 picoammeter/voltage source, and a HP Vectra PC running Windows 2000, with a high-resolution monitor. Special runtime software, written with National Instruments Labview 5.1, controls all instruments, processes, and displays the test results. An HP color inkjet printer provides paper copies of the test data in a presentation ready format. The TLP test system is supplied with a 48-pin DIP socket that can accommodate .300" and .600" width packages. It can be used for smaller DIP packages with the use of pin renumbering overlays. Sockets for packaged devices are conveniently located in a pullout drawer in the instrument cabinet, and have clearly numbered pins with easily connected test leads.
The PC screen display shown here presents the I/V plot in blue and the leakage current in red.
For a full-size display, click on the picture. To print the full-size picture, set your printer to landscape mode.
Leakage current at a selected voltage is measured after every test pulse. The rest of the test setup and the other information is also shown on the screen. Our I/V plot configuration, created by Koen Verhaege, displays both the voltage versus current and the leakage current after each TLP pulse. Both characteristics are clearly displayed to identify the pulse current amplitude that causes an increase in leakage current. The leakage current scale is the logarithmic scale at the top of the plot. The voltage scale for each test pulse is displayed at the bottom of the plot. These scales along with the pulse current can be manually selected or auto-scaled during the testing. The possibility of lost data is minimized by automatically storing all data to hard disk after the completion of each test. Hard copy prints display the same data as is presented on the screen during the test. Previously stored data can be recovered, displayed, and the plot re-scaled as desired if data review or additional hard copies from previous tests are needed. Favorite test set-ups including DUT information and test parameters can be stored for easy recall, to minimize operator input and to speed testing. The Labview runtime software can easily be changed to fit different applications, and upgrades will be provided for one year. Upgraded software has successfully been transferred to a customer over the Internet and these upgrades can be provided in this manner or can be sent on 3.5" disks. A Barth Model 45002WP Wafer Probe with dual balanced needles, specifically designed with minimum parasitics for TLP testing, is available as an accessory. The wafer probe or sockets for packaged devices can be quickly interchanged.
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The Barth Model 45002WP TLP Wafer Probe is designed to be used with the Barth Pulse Curve Tracer, Model 4002 TLP test system for pulse testing of the ESD protection I/V characteristics at the wafer level. It has two separate needles and isolated probe connections that can be independently positioned with no interaction between them.
Barth 45002 WP Wafer Probe
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The Barth TLP Wafer Probe has been specially designed to provide the same accuracy as when testing packaged devices in a socket. Testing the TLP characteristics of the device on wafer, and later when it is packaged, can provide significantly more information than is available with pass or fail testing with human body model or machine model. Either manner of connecting to the DUT allows very repeatable measurements at high pulse currents.
To minimize the mechanical problems of crossed needles in connecting to the pads to be tested, a specially designed constant impedance-reversing switch allows easy selection of the TLP pulse polarity at the pads. A strong magnetic base allows this TLP probe to be easily moved while maintaining a secure position on the table.
A controlled 50-ohm impedance throughout the complete measurement chain of our test system minimizes the measurement errors associated with the usual 500-ohm resistor connections for ordinary TLP testers. Making measurements at 50-ohm impedance minimizes the effects of parasitics.
Closeup of Wafer Probe
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Just as the Barth TLP Test System connections to the package device sockets are constructed with a controlled 50-ohm impedance, the Barth TLP Wafer Probe also has a controlled 50-ohm impedance throughout its connections to the two needle contacts at any two pads.
Testing the DUT directly from an inherently low 50-ohm source impedance provides inherently higher pulse currents from a clean test pulse with no ringing or overshoot. A perfect sub-nanosecond risetime pulse generator combined with low distortion measurements and controlled impedance connections allows the Barth TLP Test System to make accurate comparisons between the TLP characteristics on wafer and in packages.
For more information, Contact us.
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Fax: 702-293-7024