Introduction

Semiconductor ATE equipment functions by loading integrated circuit (IC) chips into a testhead, where the tester can apply varying combinations of input high and low voltages on its testpins. The tester can then read the output of the chip in response to these inputs to determine whether the chip is operating correctly.

The Aurora Project was an attempt to address the emergence of the disruptive technologies - Windows NT and CMOS. These disruptive technologies threatened to replace Teradyne's sustaining technologies of Unix and bipolar ECL.

 

CMOS vs. ECL Traditionally, Teradyne's high-end ATE has been based on bipolar Emitter Coupled Logic (ECL) circuit design. ECL is a family of bipolar circuit design that is characterized by high-speed performance. In comparison, current Complementary Metal Oxide Semiconductor (CMOS) circuits are slower because of the slower voltage switching characteristics of these devices and the tendency towards instability at very high speeds where the output voltage may not switch fast enough, resulting in invalid voltage outputs. However, the key advantage of CMOS technology is the increased functionality that could be integrated on a single chip since CMOS devices are much smaller than bipolar transistors. The net result of higher levels of integration is a dramatically smaller tester, which is then less expensive. Moreover, maintaining a "clean room" standard in large manufacturing facilities is extremely expensive, so small testers can reduce costs greatly. Additional benefits of CMOS technology include its lower power consumption and lower complexity. Windows NT vs. UNIX Prior to Aurora, all of Teradyne's tester applications ran on the powerful UNIX software platform. However, the last decade has seen performance improvements in PC hardware, making Windows a viable alternative to UNIX. The key advantage for Teradyne in switching to the Windows NT platform would be the availability of high-level development tools that would dramatically reduce software development time and cost. By leveraging Microsoft's Object Linking and Embedding (OLE) and Common Object Model (COM) standards, software engineers could create UI applications on top of pre-existing software building blocks. And while the UNIX based applications might be more familiar to customers based on their use of previous Teradyne products, the usability of applications such as Excel with the NT based UI is far greater.

CMOS Inverter [1]   ECL Inverter [2]