Microwave Journal
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Featured mmWave Testing

Survey of mmWave Semiconductor Test Systems

Including Anritsu, Focus, FormFactor, Keysight, Maury, NI, R&S, Roos and Teradyne

August 10, 2020

With the roll out of 5G mmWave systems, automotive radar and higher frequency SATCOM systems, we thought it would be timely to survey the various test solutions available at these higher frequencies. We surveyed most of the companies involved in high frequency testing about their offerings in mmWave semiconductor testing. We received inputs from Anritsu, Focus, FormFactor, Keysight, Maury, NI, R&S, Roos and Teradyne. Below is a summary of the various offerings from the leaders in the industry.

 

Anritsu

During the design process of modern microwave and mmWave communication systems, designers must characterize devices (transistors, capacitors, inductors, etc.) over a broad range of frequencies from near DC to well beyond the operating frequencies of the design.  The process of device characterization generates models used during circuit simulation and the accuracy of the model determines the accuracy of simulation and consequently, the chances for first turn success.  An important element for model accuracy is characterization of devices well beyond the operating frequency of the circuit and, in many cases, characterization well beyond 110 GHz is desirable. An ultra-wide broadband VNA, such as the VectorStar™ ME7838G with 70 kHz to 220 GHz single-sweep capabilities, provides industry-leading measurements and enables optimal device characterization for accurate models and circuit simulations. 

The Anritsu VectorStar ME7838 series broadband systems offer a number of unique attributes and performance capabilities through the use of Nonlinear Transmission Line (NLTL) technology in a unique proprietary design.  The NLTL mmWave module provides source frequencies starting at 54 GHz that is coupled to the main transmission line through substrate couplers up to 110, 125, 145 and 220 GHz depending on the module model.  The use of couplers ensures optimum raw directivity for optimum calibration and measurement stability.  The Test and Reference harmonic sampler receivers are located next to the test port for accurate signal monitoring and operate from 30 to 220 GHz.    

A critical aspect of high frequency broadband VNA systems is the connection to the device under test (DUT) measurement plane.  For on wafer semiconductor measurements the DUT input is typically coplanar waveguide (CPW).  Typically, connection from the VNA to the DUT is through a threaded coaxial connector such as the 1 mm connector.  Connection to the DUT is therefore through the 1 mm transition inside a CPW probe and limited to the 110/125 GHz range. 

To address the continuing requests for higher frequencies, Anritsu began development of the 0.6 mm coaxial connector for 220 GHz measurements. To avoid the negative consequences of connector thread wear at higher frequencies, the 0.6 mm coaxial connector was designed with an alternative guiding system for the connection to the CPW probe.  The module to probe connection uses the UG-387 flange (see Figure 1), whose tolerances support precise alignment for 220 GHz mmWave measurements, and thus accurately pre-aligns the male/female center pin connection with excellent repeatability. 

Anritsu probe
Figure 1.  Anritsu NLTL mmWave module with DC coaxial connector mating of MPI probe using UG-387 interface. 

Design of the probe body and tip was developed by MPI Corporation.  The MPI probes, the TITAN T220, directly mates with the Anritsu MA25400A module and are available in 50, 75 and 100 micron pitches for support of a wide range of DUT pad connections.

As application frequencies migrate upward, differential receiver front-ends with wide dynamic range, high sensitivity and low noise floor are becoming critically important.  A 4-port differential broadband VNA is therefore an important element during the design of microwave and mmWave communication systems.  The modular concept of the VectorStar ME7838 series of broadband VNAs offers the opportunity to upgrade from 110 to 145 and 220 GHz through the use of appropriate frequency NLTL module.  Likewise, a 2-port broadband VectorStar ME7838 system can be upgraded to 4-port configuration by adding additional test sets and modules.  For example, the VectorStar ME7838D4 is a 4-port broadband system operating to 145 GHz with true differential measurement capability (see Figure 2).  The industry has expressed a need for 220 GHz differential measurements and Anritsu will be collaborating with other industry leaders such as MPI during the development of a 220 GHz 4-port differential broadband VNA system. 

Anritsu system
Figure 2.  VectorStar ME7838D4 4-port 145 GHz Broadband VNA.

 

Focus Microwave

Focus Microwaves and Keysight have collaborated to develop a turnkey solution which makes it possible to perform high frequency fundamental and harmonic load pull up to 110 GHz with great accuracy. Combined with Keysight’s very small footprint N5290A 110 GHz PNA-X, Focus Microwaves DELTA tuners offer a very simple and efficient system which elegantly integrates on wafer.

Key Features:

  • On wafer load pull measurements up to 110 GHz
  • Measure and optimize key nonlinear parameters
  • Perform both scalar and vector load pull
  • Focus Device Characterization Software to control instrumentation and collect data
  • Measure multiple parameters over multi-octaves of frequency

mmWave on wafer load pull has always been a challenge for both test and design engineers as the inherent loss at high frequencies would limit the tuning and dynamic range on any load pull system. Keysight and Focus have collaborated to develop a turnkey solution which solves those problems making now possible to perform high frequency fundamental and harmonic load pull up to 110 GHz with great accuracy. Combined with Keysight’s very small footprint N5290A 110 GHz PNA-X, Focus Microwaves DELTA tuners offer a very simple and efficient system which elegantly integrates on wafer. 

Focus Microwaves’ new DELTA series of electro-mechanical tuners is designed specifically for high frequency on wafer measurements. The tuner’s low profile allows it to be placed within the wafer perimeter and allows for a direct connection between the probe tip and the tuner, eliminating all possible insertion loss between the DUT and the tuner. This revolutionary new tuner design enables the engineer to achieve optimum tuning range, with a tuner whose footprint and weight has been dramatically reduced.

The PNA-X is a key component in this joint solution as it is the heart of the signal generation and analysis of the load pull solution.  The PNA-X Series of microwave network analyzers are the culmination of Keysight Technologies, Inc. 40-year legacy of technical leadership and innovation in radio frequency (RF) network analysis. More than just a vector network analyzer, the PNA-X is the world’s most integrated and flexible microwave test engine for measuring active devices like amplifiers, mixers and frequency converters.

In this example, Focus has partnered not only with Keysight but MPI Corporation for the on wafer probing capability.  The rigid MPI Engineering Probe Systems are the ideal choice for RF and mmW measurement applications. The compact footprint ideally fits to the requirements of integration with complex RF power and noise characterization systems. Accurate and back-lash free RF MicroPositioners provide precise positioning of the RF probes.

MPI explicitly designed and mmW dedicated, manual probe systems TS150-THZ, TS150-AIT & TS200-THZ (see Figure 3), the high-end mmwave MP80 MicroPositioner and the single-tube MPI SZ10 or MZ12 microscopes with unique combination of high magnification and long working distance Optics enable integrating the mmW, sub-mmW VNA frequency extenders and automated impedance tuners, closest possible to the DUT, for the shortest signal path and guaranteeing best possible measurement directivity and accuracy. MPI TITAN™ RF Probe Series with its unique design and MEMS manufactured tips provide unique visibility, low resistance and high consistency of the contact even on hard to probe Aluminum pads.

Focus system
Figure 3. TS-200-THz test system.



FormFactor

Devices in the consumer, infrastructure and defense markets, are going higher and higher in frequency.  This includes devices such as 5G (28-40 GHz), automotive radar (77 GHz) and Vehicle to Everything, as well as next generation Wi-Fi (60 GHz).  These higher frequencies make it more challenging to design, fabricate and test these new RF devices. IC designers use PDKs (process design kits), which, to reduce design cycles, must be modeled and characterized very precisely – not only at the operating frequency of the circuit, but way beyond and over a very broad band. Typically, 40 GHz 5G devices would use transistors characterized up to 120 GHz with no room for error in a transistor model.  Considering the latest generation processors contain billions of transistors, small errors accumulate, meaning the IC will not perform as intended, and a new design iteration is required. Ultimately the more accurate the PDKs, the higher the success rate of IC designs and faster time to market. 

Accurate measurements in the engineering lab start with the best instrumentation, RF wafer probes, proven and traceable calibration standards and a repeatable calibration algorithm.  However, over time and process variations and under different conditions such as bias and temperature, large volumes of measurements need to be taken from many thousands of devices.  This characterization process is extremely time consuming and requires skilled engineers to operate.

One new productivity technology recently introduced allows engineers to measure more devices, and ensures known accuracy of the measurements, leading to better quality PDK’s and faster time to market.  This new technology is the Autonomous RF Measurement Assistant (AutoRF, see Figure 4). 

FormFactor System
Figure 4. Autonomous RF Measurement Assistant prober.

With AutoRF operators can make measurements 24 hours a day, seven days a week, even when measuring thousands of transistors, on up to 50 wafers at a time and over multiple temperatures.  The test cell can be left running with confidence unattended overnight and weekends.  AutoRF will constantly monitor calibration accuracy, and automatically re-calibrate when the error exceeds a defined limit.  It also re-calibrates when changing test temperature, corrects for any thermal errors introduced, and automatically aligns the probe to the pads during each touch down. This ensures confidence that measurement accuracy is always within a known limit and removes measurement uncertainty.  This new technology is fully autonomous and can controlled and monitored remotely, something that is important to all of us during these challenging times of social distancing.

In production RF wafer test, the development and rollout of 5G is driving most of the growth in RF test in semiconductor with high volume manufacturing requirements for fast, and cost effective, throughput.  The carrier aggregation, as well as higher density MIMO and the addition of 20+ GHz bands, are the primary drivers leading to a five times increase in the number of RF analog semiconductor devices (handset and base station).

FormFactor ProbeFormFactor has a few wafer probing technologies for production test.  This includes our flagship Pyramid Probe (see Figure 5) that has been used in wafer test  for many years in both RF Front End Devices (< 5 GHz filters, switches, power amplifiers), high speed devices including high speed digital components for infrastructure, and coming to automotive radar devices that operate up to 81 GHz. Pyramid Probe has been shown in test to be fully capable of volume production support to the largest semiconductor manufacturers, with capability to multi-site probing with full RF calibration for the most accurate measurements for wafer sort.

FormFactor contactsIn addition, FormFactor has been developing the Pyrana technology for even higher multi-site capability with RF performance for 5G devices (see Figure 6).  It is using vertical MEMS contactors that provide mechanical robustness and repairability that customers require, as well as good signal integrity out to 10 GHz.  FormFactor has also been working to release a new implementation of Pyrana, called ePyrana, that will be able to support test up to 45 GHz bandwidth for 5G device.  This new product will be released in the second half of 2020..

 

Keysight Technologies

mmWave semiconductor testing is a key part of the Keysight offering since the 1997 with the launch of the 8510XF Network Analyzer. This system has been designed to make fully calibrated, single-sweep measurements of broadband devices to 110 GHz, in 1.0 mm coax. The 1.0 mm connector was used to carry the signal to the DUT without the limitation of the waveguide transmission lines, previously used at this very high frequency. Cascade Microtech (now FormFactor) designed a wafer probe station and probes for the first time enabling the possibility to perform fully calibrated on wafer measurement with a single touchdown. This solution marks the start of a successful collaboration between the two companies that, during the last three decades, jointly launched several solutions, always with the objective to collaborate and maximize knowledge and competence. Today, the wafer level measurement solution is a clear example of this synergy. With guaranteed system configuration, integration and support, a wafer level measurement solution from Keysight Technologies and FormFactor provides accurate and repeatable testing, minimizing the time to first measurement, while enabling data correlation between multiple locations.

A typical configuration will include instruments from Keysight such as a PNA or PNA-X network analyzer, a B1500A Semiconductor Device Parameter Analyzer, and a N6705C DC power analyzer together with Keysight’s WaferPro Express (WaferPro-XP) measurement software platform. This is integrated with a FormFactor semi-automated wafer probe station, WinCal XE calibration software and Impedance Standard Substrates for calibration. The N5291A 900 Hz to 120 GHz PNA system is the instrument of choice for this solution (see Figure 7). This powerful single-sweep solution with compact frequency extenders deliver very accurate and stable measurements fully traceable at the probe tips, making this solution unique in the market. Two and four ports configuration are available to test the most challenging devices.

Keysight system
Figure 7.  Keysight N5291A Broadband Network Analyzer.

Integrated Photonic Test is another important area where Keysight and FormFactor are joining forces.  Integrated Photonics, often called Silicon Photonics, promises additional benefits for industrial segments such as intra data center communication and data center interconnects (DCI), Telecom, 5G and automotive connectivity, high-performance computing, LIDAR, sensing and medical. The joint solution includes:  Keysight's N4372E 110 GHz Lightwave Component Analyzer, shown in Figure 8, that delivers unprecedented bandwidth for both optical receiver testing and optical transmitter testing with guaranteed specifications for electro-optical S-parameter measurements for device traceability.

Keysight Lightwave system
Figure 8.  Keysight N4372E 110 GHz Lightwave Component Analyzer.

The FormFactor CM300xi-SiPh, with automated wafer level photonics positioning combined with Keysight's industry standard IL/PDL engines and N7700C Photonics Application Suite (PAS), to support wavelength repeatability of ±1.5 pm at two-way sweeps up to 200 nm/s within 1,240 to 1650 nm to ensure accuracy and repeatability from O- to L-band.

The KS8400A Keysight Test Automation Platform (TAP) allows fast execution, test flow visualization, analysis and insights. Keysight Test Automation on PathWave (TAP) is a modern Microsoft .NET-based application that can be used standalone or in combination with higher level test executive software environments. Instrument plugins provide test steps that can be added to work-flow sequences without needing to use instrument level programming commands. The N4370P01A LCA TAP Plug-In steps further simplify the Electrical/Optical (E/O) and Optical/Electrical (O/E) measurements by handling the interface to both the PNA instrument and the LCA optical hardware and software. The PNA settings needed for LCA measurements are provided in the test steps for easy configuration.  To ensure ease of use, the FormFactor's SiPh software enables automated calibrations and alignments and simplifies integration with Keysight's PathWave software platform, as well as optical instrumentation.



Maury Microwave

There is a growing demand for device characterization and modeling solutions above 28 GHz to support applications such as 5G frequency range 2 (FR2) and automotive RADAR as well as next generation semiconductor technology evaluation.  These applications are not only driving frequencies higher but are also pushing the envelope on modulation bandwidths.  To address these challenges, our state-of-the-art semiconductor test solutions push the boundaries of load pull with extreme modulation bandwidths as well as expanded frequency coverage to 1.1 THz.

The introduction of 5G is unlocking new levels of mobile communication performance with high speeds, low latencies and ultra-high reliability.  This will be enabled in part by using the FR2 frequency bands around 28 and 38 GHz, with channel bandwidths in the hundreds of MHz. These bandwidths pose a challenge for passive impedance tuners, where the phase variation over frequency results in the loss of impedance control and degrades ACPR, EVM and PAE performance when using wideband modulated signals.  To overcome this challenge, Maury designed the MT2000 mixed signal active load pull system, which corrects for impedance phase variations and allows users to set arbitrary impedances over a bandwidth of up to 1000 MHz at frequencies up to 40 GHz (see Figure 9). 

Maury
Figure 9. Maury MT2000 mixed signal active load pull system.

With wideband impedance control, Maury can now synthesize the load conditions presented by realistic matching networks and antennas and accurately characterize the vector-corrected performance of a DUT.  To achieve this capability, they designed the MT2000 from the ground up as a standalone one-box solution, which replaces the functions of a VNA, vector signal generator, vector signal analyzer and automated impedance tuners, thereby reducing the overall system cost and complexity while simultaneously ensuring an excellent measurement accuracy.  Additional features of the MT2000 include high speed CW and pulsed-CW measurements, baseband impedance control, time-domain nonlinear analysis, behavioral model extraction for 5G circuit design, and I/Os for digital pre-distortion and envelope tracking tests.

When active devices are characterized at frequencies beyond 5G, additional challenges for passive impedance tuners arise, especially for on wafer measurements. Traditional on wafer passive load pull systems suffer from a degraded tuning range at the DUT reference plane due to the insertion loss of the RF probes used to make a connection with the DUT.  While a standalone passive impedance tuner may be able to present a |Γ| > 0.9 at 75-110 GHz, the system loss may reduce the tuning range to |Γ| = 0.6-0.65, often below the expectations of a modeling or design engineer.  The latest vector-receiver load pull system using IVCAD software, designed in partnership with AMCAD Engineering, enables hybrid-active load pull up to 110 GHz, and is able to increase the tuning range to |Γ| = 0.92 or higher at the DUT reference plane.  The increased tuning range allows engineers to fully characterize their transistor technologies, determine ideal matching conditions for amplifiers and circuit designs, and better validate their nonlinear models.  To best support their customers, the company is expanding the MPA-series amplifier product line to include high-power mmwave amplifier modules in bands between 50 and 110 GHz for active and hybrid-active load pull. 

At frequencies above 110 GHz, the system losses become so high that the impedance tuning range of passive tuners is significantly limited.  As an example, a 4 dB insertion loss of a waveguide probe at 300 GHz would reduce a hypothetical tuner’s |Γ| > 0.9 to less than 0.3 at the probe tip.  To overcome this challenge, Maury offers fully active load pull up to 1.1 THz with their strategic partner Vertigo Technologies and our MMW-STUDIO solution. MMW-STUDIO uses standard VNAs and waveguide extenders (e.g. Keysight and R&S VNAs using VDI or OML extenders) and enables high-resolution amplitude- and phase-controlled S-parameter, power sweep and load pull measurements with |Γ| > 0.9 at the probe tip at  frequencies up to 1.1 THz (see Figure 10). With MMW-STUDIO, engineers can now extract and validate transistor models, full characterize transistors and circuits, optimize amplifier design and validate the performance of circuits and systems under mismatched load conditions at mmW and sub-THz frequencies.

Maury system
Figure 10. Active load pull up to 1.1 THz with their strategic partner Vertigo Technologies and our MMW-STUDIO solution

 

NI (National Instruments)

Many companies working on mmWave devices for 5G applications are still defining the final architecture of their devices, how to package them and what level of performance they can achieve. Since these factors are not final, engineers working on applications need flexible mmWave test and measurement solutions. NI is in a unique position to offer this flexibility and the speed required to take measurements on a broad range of mmWave device types.

Taking advantage of the modularity of the software-connected PXI platform and mmWave Vector Signal Transceiver (VST), NI offers a test solution that is easy to configure to fit the needs of 5G mmWave devices. The mmWave VST, a wideband instrument that combines a vector signal generator and vector analyzer, is capable of covering both 5 to 21 GHz intermediate frequency (IF) and 5G frequency range 2 (FR2) mmWave bands. The compact mmWave test heads, which are external to the PXI chassis, minimize signal loss by bringing the signal closer to the DUT interface and are easy to adapt to physically different test setups (see Figure 11).

NImmWaveSetup
Figure 11. NI VST, mmWave modules and software for 5G mmWave testing.

In addition, engineers can select either direct or switched-path configurations of the NI mmWave test heads. This flexibility helps achieve the best measurement performance depending on the DUT types, whether they are higher-power devices or multichannel types such as beamformers. Figures 12 and 13 show different types of test configurations taking advantage of the mmWave VST architecture.

NI system 1
Figure 12. NI mmWave VST connected to a 32-channel – IF-RF Beamformer.

NI system 2
Figure 13. NI mmWave VST configured for over-the-air (OTA) testing of IF to RF Antenna Modules.

5G semiconductor companies continue to forge new developments in antenna-in-package (AiP) and antenna-in-module (AiM) devices. NI introduced a 3D-scanning mmWave OTA validation solution that helps characterize the spatial radiation performance of these devices 5 to 10 times faster than traditional scanning techniques. This solution can be adapted to high volume parametric OTA production test using the same instrumentation, which helps ensure reliable AiM performance once assembled as part of a system.

Additionally, NI’s modular instruments, like the mmWave VST, readily deploy to high volume semiconductor manufacturing floors within the NI Semiconductor Test System (STS). The STS takes advantage of the same measurement science and high-precision lab instrumentation in a robust automated test equipment (ATE) FormFactor. STS maximizes yield on the production floor by leveraging lab-grade measurement performance while applying highly optimized measurement algorithms to accelerate test speed. Furthermore, our vision is to connect the performance insights from a large amount of characterization and sample data to create more targeted and efficient test methodologies and sequences. Then, by mining production data, we can understand how to improve the initial design and validation stages, and further accelerate the rapid design-to-production cycle of mmWave devices.

NI offers a test solution that empowers engineers across different stages of mmWave device testing – from validation to automated characterization to production test. The commercialization of mmWave devices is new and exploding. NI’s high-performance, flexible mmWave test solution solves the challenge of testing a variety of devices in a condensed timeline while ensuring the highest device quality.



Rohde & Schwarz

To provide turnkey solutions for semiconductor test, Rohde & Schwarz cooperates with a variety of partners.  In particular, network analyzers from Rohde & Schwarz provide the essential measurement data. Partners have chosen these instruments due to their high accuracy, high speed and reliable performance, all meeting the specifications diligently documented in data sheets.

Wafer level characterization is a critical part of RF and microwave semiconductor design and debug, including modeling modern high-performance semiconductor devices. For on wafer characterization of RF and mmwave components, Rohde & Schwarz collaborates with long-term partner the MPI Corporation in Taiwan, to offer turnkey solutions for measurements on semiconductor components. Rohde & Schwarz contributes network analyzers directly supporting frequencies up to 110 GHz with frequency converters extending the range up to 1,100 GHz, developed to work in conjunction with MPI wafer probers in all-in-one solutions designed for precision analysis of 150 and 200 mm wafers:

  • The TS150-THZ is the first 150 mm wafer dedicated probe station on the market designed explicitly for mmwave and THz on wafer measurements.
  • The TS200-THZ for 200 mm wafers adds active impedance tuner integration providing accurate tests for the combination of requirements for mmwave, THz, and automated impedance tuner applications (see Figure 3).

For developing active components such as power amplifiers running under compression showing nonlinear behavior such as impedance variance and reflection effects, load pull varies the load impedance at the DUT to determine the optimum matching.  R&S partners Focus Microwaves and Maury Microwave provide packages featuring R&S ZNA, ZNB (see Figure 14), and ZVA network analyzers for load pull measurements from 10 MHz to 110 GHz.

RandS VNA
Figure 14. R&S ZNB vector network analyzer.

For modulated tests of semiconductors in 5G or satellite links, according to the target application the wideband vector signal generator R&S SMW200A supports up to 2 GHz of bandwidth and 44 GHz RF frequency, the signal and spectrum analyzer R&S FSW even goes up to 90 GHz with an with an internal demodulation bandwidth of 8.3 GHz due for release in July.

For production and characterization of 5G FR2 RFICs, the radio communication tester R&S CMP200 offers a unique highly integrated solution supporting CW and modulated tests in the FR2 frequency range. The combination with the IF connections enable cost-efficient test of highly integrated RFICs with an IF connection. The compact shielding chamber for OTA test R&S CMQ200 pairs ideally with the communication tester for packaged 5G FR2 RFIC devices, which typically also include a mmWave antenna.

For modulated tests, the internal and fully calibrated demodulation bandwidth of the signal analyzer R&S FSW is unique on the market. Up to 8.3 GHz bandwidth for analyzing wideband radar chips or linearization using wideband DPD algorithms for mmWave power amplifier transistors and integrated ICs.

The new high-end network analyzer R&S ZNA offers high dynamic range ensuring highest measurement speed paired with exceptional repeatability and accuracy. In addition, R&S ZNA – together with its predecessor R&S ZVA – are the only integrated network analyzers offering four independent sources to enable fast and in-depth mixer characterization.

The multiport network analyzer R&S ZNBT with up to 24 ports and frequencies up to 40 GHz is ideal for parallel testing of multiple devices as well as the latest high-integrated ICs such as  multichannel active beamformers for 5G or satellite links, which have typically from 5 to 17 ports. The high integration in the R&S ZNBT platform simplifies the handling and the calibration of the multiport test setup.

Future enhancements include the high-end vector network analyzer platform R&S ZNA increasing its frequency range and adding functions for semiconductor testing needs. The signal and spectrum analyzer FSW internal demodulation bandwidth will increase from 2 to 8.3 GHz for automotive and industrial radar chipsets and beyond 5G research is launching soon.

 

Roos Instruments

While mmwave has traditionally been considered a niche application that is largely ignored in high volume production, with the advent of automotive radar and now 5G NR, these frequencies are becoming more mainstream. To successfully transition mmwave devices from laboratory bench-top setups into production test requires a holistic test strategy that addresses the added complexity of high volume economics and cost dynamics. With over 15 years of experience working with custom production mmwave applications, Roos has gained valuable insight into the challenges their customers face at these frequencies. This has helped the company develop novel solutions in four key aspects of the test system that determine success at millimeter frequencies: instrumentation, interconnect, interfacing and integration.

Starting with the instrumentation, the key aspect of the Cassini ATE is a modular and configurable instrument architecture. This enables drop-in test set instruments that extend the frequency capability of the standard 20 GHz source and vector measure core with VNA measurement capability and performance comparable to bench instruments (see Figure 15). This provides better device correlation while allowing the test system to be tailored to the frequency or application requirements. The configurable nature of the system architecture provides capital expense control and greater port efficiency while allowing for future frequency and capability expansion well into the 100 GHz range.

Roos components
Figure 15. Test Set instruments provide drop-in, multiport VNA test port capability for the Cassini ATE System.

Roos has a unique device interconnect solution that is a departure from the traditionally fixed, multi-layer production load boards as it is designed to be a configurable environment that incorporates high-performance mmwave interconnects and components. It is comprised of two separate, interconnected layers: a general-purpose fixture and socket/probe card for specific devices or applications as shown in Figure 16.

Roos setup
Figure 16. Cost Breakdown of a Cassini device Interface for mmwave application.

The fixture provides a configurable environment that extends the test system’s measurement port capability with reusable off-the-shelf relays, switches, microwave cabling and waveguide, within a rugged, RF-shielded enclosure (see Figure 17).

Roos costs
Figure 17. Paralleling microwave and mmwave resources inside the fixture(left). This provides cost effective port expansion to the existing test system architecture for specific applications (right).

This enables a less complex socket/probe card design, that is both better performance at mmwave frequencies (lower losses, less parasitics, and optimized ground plane) and a more cost effective production consumable (see Figure 18).

Roos reuse
Figure 18. Cost Breakdown Consumable/Reuse Comparison of a Cassini Device Interface and traditional multi-layer load board for mmwave applications.

The ubiquitous nature of microwave and mmwave interfaces between instruments and the device interface layers belies their critical function in the overall solution. Cassini’s interface provides both a repeatable setup for successful calibrations that translates to accurate and repeatable measurements, while also satisfying production floor requirements of no specialized tooling or operator training for setup and servicing. Roos’ patented blind-mate microwave and waveguide interfaces provide self-alignment and pressure contact compliance without any tooling or manual manipulation. This insures consistent and repeatable setup of the test system and test bench that is suitable for high volume insertions. They have partnered with several leading manufacturers of probe and socket cards such as Cohu, Form Factor and Yokowo to offer interfaces on their products and ease the introduction of mmwave test into production (see Figure 19).

Roos interface
Figure 19. Interspersed 80 GHz waveguide and 40 GHz blind-mate signal interface for use with a FormFactor/Cascade Microtech probe card.

Traditionally, the integration of the test system and device-specific fixturing is left to the customer due to the custom nature of the application. By contrast, Roos provides a complete mmwave production solution in both the instrument system architecture and the software to provide; tester configuration management, dynamic instrument and test system integration, and most importantly, layered vector calibration to de-embed measurement results. Ultimately this is where the production proven instrumentation, Interconnect and Interface experience of Roos Instruments and the Cassini platform pay big dividends in time to market, risk mitigation and cost savings for our customers.

 

Teradyne

Teradyne has been pretty quiet about its offerings but has 5G test solutions provide customers with an easy upgrade path from traditional sub-6 GHz testing into the mmwave frequency range. This enables customers to re-deploy their UltraFLEX ATE installed based with mmwave test capability.  

For example, Teradyne’s UltraWave-MX44 instrument the UltraWave24 (sub-6 GHz) capability up to 44 GHz to address the 5G-NR standard while maintaining full DIB and docking compatibility with existing sub-6 GHz UltraFLEX ATE testers. The UltraWaveMX44 is a single slot instrument in the UltraFLEX system and acts as an extension to the UltraWave24 RF instrument. It provides dedicated mmWave frequency blind-mate coaxial DIB connections which are designed to withstand the challenges of a production environment while providing the performance to source and measure high quality 44GHz test waveforms to the device.

The UltraWaveMX44 seamlessly integrates into the manufacturing flow by maintaining fully legacy compatibility with existing applications. Existing RF DIBs can continue to be used with a system configured with the UltraWaveMX44 instrument without any system reconfigurations.

There are 32 mmWave ports available on the UltraWaveMX44 making DIB design significantly easier because sensitive signal switching is not required on the DIB. And, the system can be configured with up to 128 mmWave ports which may be required when scaling for high site count multi-site testing.

A patented active thermal control within the instrument guarantees temperature stability to ensure that high-performance specifications are meet in the engineering and production environments. The UltraWaveMX44 features an integrated power detector which provides specification traceability. The instrument’s frequency range covers 6 to 44 GHz. The instrument has 800 MHz bandwidth and can achieve greater than 2 GHz bandwidth through its high-performance path. It supports RF and IF interfaces for both 5G IF transceiver and 5G RF Beamformer device coverage. There is a dedicated low phase noise DUT reference clock operating from 100 MHz to 6 GHz to supply a precision reference clock for devices with integrated PLLs.

Teradyne’s extendable 5G test solutions are used for testing 5G devices in characterization and in mass production at wafer probe, package and OTA module test insertions. Teradyne’s UltraWaveMX44 mmwave test solution provides an easy ATE upgrade path from traditional sub-6 GHz to mmwave testing.  This is a key feature as manufacturers have a large installed base of sub-6 GHz ATE equipment (previously used for 4G) and desire to re-deploy such installed base with mmwave testing capability for 5G.