Automated Pick-and-Place Handler Enables Test Engineering Efficiency in Lab Environment

By Zain Abadin, Director, Handler Product Engineering and Marketing, Advantest

In the laboratory environment, the principal goal is to complete development and pre-production testing of integrated circuits (ICs) as quickly and cost-effectively as possible. An associated challenge is to ensure that tester and operator resources are utilized efficiently so that testing can be completed on or ahead of schedule, further improving time to market (TTM).

The typical test approach is to have an operator manually load the devices into the test sockets, and then run the specific test for the defined time per the device maker – this could range from 5 seconds to 30 minutes or more per device. The actual number of devices also varies; in pre-production, there may be as many as 10 trays, containing a few hundred ICs. Testing in this manner is an inefficient use of labor, engineering, and tester resources. For short test times, this means an operator sitting by the tester to load/unload devices under test (DUTs). For long test times, the operator inserts a device and moves to another task on the floor. If an operator isn’t immediately available to change the DUT, the test process can be extended or delayed, causing it to take longer time to complete the lot and increasing the cost of test and TTM.

A scalable handler that can be used for both ATE and bench testing is the ideal solution to these challenges, allowing development and pre-production testing for a variety of device types and batch sizes to be completed faster, and enabling devices to be sent to market in a timelier manner. The result is a significant savings in both labor and cost of test.

Advantest’s M4171 handler delivers an efficient solution to meet the mobile electronics market’s needs for cost-efficient, thermally controlled IC testing. The unit is small – about one-quarter the size of other handlers – making for a small footprint and easy docking. The single-tray handler utilizes one contact arm to pick up a device from the tray and places it into the socket. Once the device has been tested, the same arm moves in to pick up the device and place it into its post-testing position in the tray.

Flexible operation equals faster results

The M4171 was created with a range of features intended to enhance lab efficiency (Figure 1). These features are summarized below.

Remote accessibility/control from any location

To run tests locally on the handler, the operator is on site to load the trays of DUTs, run the automated test process and remove the trays when testing is complete. However, when the operator’s workday has ended, there will be handler/tester downtime until the next shift or the next day. The M4171 includes cameras that allow a team member at another location, anywhere in the world, to not only monitor activity and view results remotely, but also to actually operate the handler remotely (Figure 2).

This means that the handler can be run at any time of day – a team member located across the country or across the globe can access the handler during his or her workday, moving, docking and undocking the handler, and running the desired tests. In turn, this allows companies to spread out their global resources and schedule operation so that there is less equipment downtime, i.e., a higher utilization rate. Testing can thus be completed faster, speeding TTM.

Multi-mode testing to expedite the test process

It can run multi-mode test processes, both pre-defined and user defined, including automated testing, automatic ID testing, output tray re-testing and manual testing (Figure 3).

High accuracy cycle temperature across wide temperature range

In addition to its automated device handling and remote operation, the M4171 is unique due to its wide-temperature sensor-based thermal-control capabilities, which range from -45° C to 125° C.  The M4171’s tri-temp technology enables operation of the handler over a broad range of temperatures.  The system uses direct device-surface contact, which enables quick temperature switching for fast ramp up and ramp down. With this capability, ramp-up, soak time, ramp-down and time-at-temperature can be set up all at once, and run one after the other.

The handler collects data continuously throughout the process, enabling significant time and resource savings (Figure 4). In fact, cycle temperature testing time can be reduced by more than 40 percent compared to manual thermal-control solutions.

Flexible bin assignment for output

A unique capability of the handler is that it enables pre-programmed binning within the output tray – once the handler and tester are docked, the tester can tell the handler into which bin a device should be placed. This allows the customer to utilize different binning approaches for different devices or batches, to pause in the test process or specify retesting. As Figure 5 shows, the user can define bins within the tray as pass, fail, retest, empty row, etc. – whatever lab functions are desired.

A label or category can also be assigned to a device within the trays, and that label stays with the device throughout the test process. With this capability, the customer can easily tell the devices apart by tray section – which passed, which failed, which need to be retested, etc. This is vital to ensure rapid transition between batches, or from the lab environment into pre-production.

Fully compatible with the V93000 and T2000 platforms as well as other testers, the M4171 also features a 2D code reader, a device rotator and a high-contact force option.  In addition, users can quickly convert the handler to accommodate different setups – with only a few parts to change, conversion takes just 10-15 minutes compared to 30 minutes or more on other handlers. Key specifications for the handler are shown in Figure 6.

A cost analysis using an example test time of 120 seconds and a quantity of 20 testers reveals that using the handler enables a 69-percent reduction in cost. Not only can each operator handle more units per hour and more test cells, but the customer has the flexibility to test triple the number of units using the same number of tester (Figure 7).

The M4171 is available now, providing integrated device manufacturers (IDMs) and outsourced semiconductor assembly and test companies (OSATs) with a compact, cost-efficient engineering test solution that delivers both thermal control and automated device handling.

Speedier, More Accurate Testing of Automotive Sensors Is Here

By Zain Abadin, Director, Handler Product Engineering and Marketing, Advantest

The amount of electronic content in automobiles continues to grow at a brisk pace, and sensors represent a significant percentage of cars’ electronics. MarketsandMarkets estimates that the automotive sensors market alone will reach US$36.42 billion in value by 2023, at a compound annual growth rate (CAGR) of 6.7 percent between 2017 and 2023. 

Sensors in cars are used to monitor and control a host of functions. Pressure sensors are growing at nearly the same rate as the overall automotive sensor market. Technavio reports that the global automotive pressure sensors market is anticipated to post a CAGR of more than 6% between 2017 and 2021. This is due to growing demand for fuel efficiency, safety, and reduced emissions. Many different types of pressure sensors exist, with varying requirements as to the level of pressure they require.

One key subset of pressure sensors – exhaust and side and center airbag sensors – requires very low pressure. The thresholds at which they should activate and deploy are well below 1 megapascal (MPa), and as low as 600 kilopascal (0.6MPa) because their ability to deploy when needed is absolutely critical to protect passengers’ health and safety. Therefore, it’s imperative that they be accurately tested to ensure their functionality prior to purchase and use of the vehicle into which they’re integrated.

The traditional test flow for these sensors is done at the wafer level, conducting logic and DC test on the sensor ASIC first, then performing DC test separately on the sensor element, i.e., the part of the logic device that will make the sensor actually deploy. Normally, these tests are performed separately, then the ASIC and element are tested again as a unit, utilizing manual handling to move the sensors between test steps. This includes a range of temperature tests, which are essential to ensure desired functionality regardless of whether the car is being driven in Palm Spring in the summer or Minnesota in the winter. The multiple steps and manual handling associated with the typical test approach impact test time and cost, and can delay time to market (TTM) for the carmaker.

New solution eases pressure on users

Advantest proposes a new approach, combining a stimulus test cell with an automated handler, creating a module that can accommodate trimming, temperature, logic and DC test all in one unit. Once these are complete, all that is left is to install the module and perform a quick production test to ensure the module is installed properly. This solution allows the user to omit several individual tests and perform the necessary tests in one solution, all at the same time.

Figure 1 illustrates the difference between the current methodology and the Advantest solution, which combines a test handler and EVA100 measurement system with an HA7200/7300 temperature and pressure stimulus unit. Together, they create a compact and easy-to-use production-volume test environment.

Figure 2 shows the test cell setup, which is basically the same regardless of the desired pressure unit. The HA7200 can measure absolute pressure on up to four devices under test (DUTs), which is the ideal choice for airbag sensors. The HA7300 is designed for testing differential pressure sensors (e.g., exhaust sensors), whose use is becoming more pervasive as vehicle designs continue to focus on improving fuel economy and reducing hazardous emissions. The HA7300 enables accurate application of two separate pressures within a short time, using two ports, and can test up to eight DUTs. The setup is flexible, similar to a rack, so the pressure modules can be easily swapped out to test both types of pressure sensors. Figure 2 also includes some of the key specs associated with the setup – notably, the wide range of temperatures and pressures that can be accommodated, and the associated high degree of accuracy that can be attained.

Two major benefits of the Advantest stimulus solution are its ability to perform temperature and pressure test simultaneously, and to minimize the stability time for both. This is due to the use of dual fluid active thermal control (DF ATC), which works together with the conduction employed in the unit to maintain device temperature.

In the automotive market, testing and specifications are highly restrictive – because public safety is parament, the test levels are set, and then performed over and over. There is no margin of error, which means these is no sampling; every device must be tested. This has led to test houses creating their own custom solutions, which are costly. As Figure 3 shows at left, four setups are required for the in-house solution, necessitating a very large footprint. In addition, multiple operators are needed due to manual handling, which is a drain on time and resources.

Devices are trimmed first at high temperature (HT) and high pressure, next at room temperature (RT), and then they are tested at low temperature (LT), after which they are brought back up to HT and tested again prior to output. This means the device is heated or cooled to the desired temperature, then brought to the tester. However, during transport, the device temperature shifts by some degrees before it is tested.

At right in Figure 3, is the process enabled by the Advantest test cell system. The setup includes the same number of tests, but because it based on the use of a handler, the DF ATC technology and pressure sensor module with much smaller chambers, the system footprint is considerably smaller than that of the in-house approach. Also, because the test cell uses conduction rather than convection, the device is always in contact, ensuring the desired temperature is accurately maintained – simultaneously with the pressure. With this approach, system cost is cut by about half, power consumption is reduced by 25 percent, and operator resources are used much more efficiently.

Looking ahead – to the current sensor

Another automotive sensor challenge for which a new test approach will soon be needed is related to current sensors used in electric vehicle (EV) batteries and motors.  New batteries and motors will be much larger, and the current needed to test these sensors may exceed 1000 amps (A), while accommodating the requisite wide ranges of temperature – within an acceptable guard band.

In order to test such current sensors under the 1000 A application condition, sufficient heat generation measures and safety measures are required, so huge test and stimulus equipment is required. Therefore, a method of applying a magnetic field at module level instead of applying a current at unit level is desired to realize a small equipment. However, it is a big technical challenge to apply magnetic flux uniformly while maintaining temperature.

Together, these challenges have created major hurdles that the test industry needs to address. Thanks to increased regulation, demand for electric vehicles is on the rise – Technavio anticipates a CAGR of 42% for current sensors, with the market reaching $87 million by 2021. Meeting this demand will require better and faster testing of current sensors than is being done today. Advantest is leveraging its expertise in sensor testing to investigate new advanced solutions. We look forward to sharing the results of these efforts with you in the near future.