Test & Simulation Feature Stories

Semiconductor System-Level Test: 3 Reasons Conductive Thermal Accelerates SLT Adoption

One way to maintain the delicate balance between quality control and economics in high-volume manufacturing (HVM) of complex electronic devices is through system-level testing (SLT).

For all its benefits, however, one additional—and underrecognized—aspect of SLT is its ability to control the thermal testing environment of a DUT during massively parallel test scenarios.

Compared to common convective thermal approaches, SLT is more:

  • Precise. The conductive thermal approach results in tighter statistical distribution to better identify outliers and marginal units.
  • Dynamic. Advanced features like Active Temperature Control (ATC) in premium SLT equipment respond rapidly to changing thermal conditions in the DUT.
  • Efficient. SLT's tri-temperature range (i.e., cold, room, and hot) creates opportunities to consolidate separate thermal insertions into one.

Let's take a brief look at these three thermal aspects of SLT.

More Precise: Eliminating Thermal Variability

One popular convective approach primarily relies on airflow and heatsinks to dissipate heat and manage compute loads. That might be cost-effective, but it can't properly accommodate accelerated testing scenarios, advanced DUTs with high transistor counts, and massively parallel environments.

By contrast, next-gen conductive thermal SLT solutions apply heating and cooling stimuli directly to the DUT and not the surrounding circuitry. This premium approach employs refrigerant, too, which allows for much faster responses to the dynamic compute loads in DUTs while ensuring greater precision in measuring their effects (typically, +/–1°C up to 85°C).

As a result, engineers can establish a more confident baseline of device behavior and even reduce the test duration.
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More Dynamic: Taming Thermal Runaway

With higher gate count, a major risk in HVM is thermal runaway. Left unchecked, this sustained self-heating loop can cause catastrophic loss and severely affect yields.

Closed-loop conductive thermal technology enables device manufacturers to mitigate many of those risks. It avoids catastrophic thermal runaway situations by maintaining a constant DUT temperature versus dynamic compute loads. And with a solution like the ATS 5034 SLT Platform, the highly customizable Astronics ActivATE™ software can stay safely ahead of the thermal ramp.

The conductive thermal approach with SLT equipment also mirrors real-world conditions and the DUT's performance within them more accurately. Granular independent DUT control on the test interface board (TIB) enables engineers to independently set temperatures to within +/–1°C on a per-site basis, which helps to lock down potentially problematic variables.

More Efficient: Consolidating Thermal Insertions

Sure, greater accuracy and responsiveness are obvious benefits. But what about streamlining? Does adopting SLT mean sacrificing workflow optimization?

Not at all. The ATS 5034 SLT Platform, for example, ramps quickly and seamlessly between the full range of temperature conditions—cold, room, and hot—using a single insertion for maximum efficiency and lower cost of test (CoT) through station consolidation. That means SLT can not only augment but supersede thermal testing stations in an existing workflow by substituting for conventional burn-in. (Our C-Brief #2 explains this in more detail.)

Along with replacing some aspects of the structural test (ST) and functional test (FT) stages, solutions like the ATS 5034 SLT Platform can test up to 5,000 units per hour (UPH) per machine to achieve the uncompromising quality control and high cadence required in the emerging HVM landscape.

Every Degree Matters: The Evolution of Thermal

As vital as thermal testing is to quality assurance, conventional implementations carry the inherent risk of under- or overtaxing DUTs. Ultimately, a manufacturer winds up sacrificing either test coverage or yield.

Yet every degree matters. That's why next-generation electronic devices call for an evolution in thermal testing. The unparalleled precision of conductive thermal narrows test-data variability and creates a more confident DUT baseline for labeling outliers and marginal units. Its rapid thermal response capabilities are better suited to dynamic thermal conditions in the DUT and help mitigate expensive risks.

What's more, when paired with a tri-temperature SLT insertion, conductive thermal also allows for unique efficiencies like full-stage automation and workflow consolidation that can lower CoT.

To delve deeper into the advantages of closed-loop conductive thermal and the ATS 5034 SLT Platform as a proven turnkey testing solution, download our C-Brief #4 on this topic. And to learn more about semiconductor SLT in your workflow, please get in touch with us.