Cascade's Ahlgren Offers Clear View of Semiconductor Test

As process nodes shrink and effects such as intra-die variations begin to raise significant quality issues, semiconductor manufacturers will need to test early and test often. That’s the view of Debbora Ahlgren, vice president of marketing at Cascade Microtech and the vice general chair of the 6th Test Vision 2020 Workshop to be held July 10-11 in San Francisco in conjunction with Semicon West.

Debbora Ahlgren

The move to 450-mm wafers, Ahlgren said, will offer opportunities not only for traditional tester companies like Advantest and Teradyne and prober companies like Cascade, but also for companies like PDF Solutions that address issues very early in process development. She added, “I for one am not a proponent of the belief that wafer probing at 450 mm simply scales so I’m particularly looking forward to discussion of that topic at the workshop.”

Ahlgren’s industry experience has given her a vantage point for observing test trends, many of which will be illuminated at the Test Vision 2020 Workshop. Her current position offers her a close-up view of the probing and contact technology that provides access to electrical data from wafers and IC packages. You can’t test, she said, if you can’t transfer signals between the DUT and the tester.

Before joining Cascade last July, Ahlgren had worked with a variety of firms in many aspects of semiconductor test. She consulted with HP before it spun off Agilent Technologies, and she was instrumental in the subsequent spin-off of Verigy (since purchased by Advantest) where she assumed the position of chief marketing officer. She also had experience at Schlumberger, whose semiconductor test operations were ultimately absorbed into what’s now LTX/Credence. In addition, her view is enhanced by experience she gained in metrology at KLA-Tencor.

On the software side, she served as senior vice president of sales and marketing for OptimalTest, and she expects software to be a key focus at the workshop. Big data is all over the news, she said, and it’s equally as important in semiconductor test as in other industries. “The role of test is to gather data to inform decisions—not only to determine the goodness of devices, but also to tune processes and enhance the effectiveness and efficiencies of our test operations,” she said.

“Electrical test is the ultimate arbiter of the goodness of our devices—there’s no question about that—but test data should be used for so much else these days,” Ms. Ahlgren continued. And, she said, her understanding of the importance of data also was instrumental in her driving Verigy’s acquisition of Inovys, a provider of yield enhancement, failure analysis, and debug solutions.

Last year’s workshop covered topics including protocol-aware ATE, navigating the sea of test data to boost overall equipment effectiveness, MEMS test, and 3-D IC test.¹ An additional topic that Ahlgren expects to be of interest to workshop attendees this year is the integrated test cell. Advantest, she noted, has long offered test cells with its own handlers, but now Teradyne, too, is offering integrated test cells.

Test vendors, she said, “can bring the components of the test cell together to deliver one plus one plus one equals five. I think there’s a lot of opportunity to create ‘integrated measurement solutions,’ which, by the way, is Cascade’s phrase for it, where you are delivering far greater value to your customer by really defining the performance envelope and owning the performance of that envelope.”

This year marks the first in which Ahlgren serves on the Test Vision 2020 Workshop committee, although she has been an active participant in previous events. “What it has always intended to do, and what it has been successful at, is to provide a view of where test is headed. The name implies ‘forward looking.’ We’ve debated tester architectures, we’ve debated directions in terms of software, and we’ve debated convergence in the test space.” Workshop sessions also have pushed the boundaries of semiconductor test to address system-level test, she said, adding, “Many predictions that have come out of the workshops have come to pass.

“What I really enjoy about the venue is that there are lots of networking opportunities and panel discussions” in addition to speakers’ presentations, Ahlgren said. In short, she added, “It’s a forum for innovation—bringing together test equipment developers and tool providers as well as the users. It brings together a very condensed community of the thinkers and doers in semiconductor test.”