Temperature Control is Getting Significance in IC Test Flow

Semiconductor technology is evolving fast. About every 2 years, IC manufacturers introduce products with new process node. Today, 7nm product is becoming the norm and 5nm is on its way to be the next mainstream offering.

From the test aspect, these products with increasing transistor density making it more vulnerable to temperature related defects. This puts pressure on mission critical devices that need to undergo extreme temperature test in order to screen out temperature-related defects. A reliable temperature control system would be essential to ensure accurate screening.

As the production volume of semiconductor on the rising trend alongside with the expected demand in 5G and IOT market, there are opportunities where a cost effective temperature control solution can do a significant saving in semiconductor test.

AEM sees the key for these needs is a Scalable Active Thermal Control System.

Contact-based Active Temperature Control Offers Better Accuracy

Contact-based Active Thermal Control (ATC) is one of the methods that offer accurate temperature control on the DUT over chamber-based convection method.

Temperature control on the DUT using chamber-based method is challenging in ensuring all the DUT are maintained within a tight tolerance of temperature. This is especially obvious in a large size chamber as the air flow is hardly to be even in all the corners.  A higher parallelism will lead to higher temperature variations across the DUT arrays.

Whereas in contact based active thermal control, it has a temperature control mechanism for individual DUT to ensure uniform test temperature is applied across all DUTs. This instilled confidence in IC manufacturers to guarantee the temperature margin they have on their product. 

While there are many methods the industry uses in contact based ATC, AEM thinks liquid cool is the most sensible method for its capability to handle high thermal load, temperature control accuracy, and scalability.

In AEM’s contact-based thermal control solution, the DUT is engaged by a highly efficient heating & cooling device. It can be designed in a very compact form with a low manufacturing cost thanks to the micro-structure design (patent pending) that is able to maximize the wetted surface area of the heat exchanger. The micro-structure is also engineered to further enhance the heat exchange efficiency by breaking the boundary layer of fluid flow which often is the limitation of a straight channel cooling block. 

The compact form factor of this cooling mechanism enables the scalable Active Thermal Control solution of AEM’s AMPS system, which is architected to house up to 480 sites within a single handler. It also enables high parallelism test for high power devices in a compact space. 

How We Make Contact-based ATC Solution Cost Effective? 

We often measure the cost effectiveness of various solutions in two aspects.

Initial cost per test site – the cost of a new system and the infrastructure required.

Running cost per unit – Part replacement, power consumption, and other consumable items.

AEM’s ATC solution is engineered to support a large scale test system. In our many-testers-one-handler concept, the infrastructure is built to support multiple testers with asynchronous capability. The high parallelism helped mitigate the one-time cost of the infrastructure across many sites. The more test sites in a system, the lower cost per unit tested.

By doing it at large scale, the running cost per unit can be kept low through centralizing the cooling of liquid. And re-circulating of the cooling fluid is the reason of low consumable cost.

Not Just a Regular Temperature Control System

AEM ATC system is designed to support 100s of DUTs with test temperature range from -40C to +125C. With each DUT at independent Active Thermal Control, the asynchronous characteristic of the system makes efficient use of the centralized cooling of liquid for responsive temperature control. 

With the tri-temp capability to support wide range of temperature, it enables multiple tests within a single insertion. 

Gain a Competitive Edge in the Semiconductor Test Market

As the industry is advancing towards more complex IC design with mission critical needs, the cost of test is expected to rise with more devices require stringent test condition with temperature control. IC manufacturers will need a highly controllable and cost-effective thermal control solution to gain an edge in this ever competitive market. 

AEM is bringing this solution to the market to helps IC manufacturer in optimizing the cost of their test process.

AEM’s Massively Parallel Asynchronous Active Thermal Control System handles 100s of DUTs simultaneously with each at different temperature.
AEM’s compact heat exchanger design with microstructure to maximize wetted area

ABOUT THE AUTHORS

Chan See Jean, Sid

Director in Engineering

AEM Singapore Pte. Ltd.

sid.chan@aem.com.sg

Stuart Pearce

Snr Director Field Marketing

AEM International (USA)

stuart.pearce@aem.com.sg

www.aem.com.sg