1. Size Matters
I spent all of last week in Taiwan which enjoys 20% of the world-wide OSAT factory space. Taiwanese
companies also own much of the OSAT capacity in China. As such, you can imagine the substantial
deployment success here for the low-cost NI Semiconductor Test System (STS).
I’m sitting here in the Narita, Japan airport (on my flight home to Austin, Texas) thinking about all the
National Instruments Customers who have specified PXI for Semiconductor Production Test. There are
many considerations when specifying an optimized ATE production test architecture for targeted device
product families. Customers ask me what is the most popular NI Semiconductor Test System (STS)
enclosure for Production Test? I’d like to put this question to bed, and explain that Size Matters.
The most popular STS enclosure for Lab Characterization and Sample Test (example Single-Site Test) is
the T1. The T4 enclosure is very popular for Customers seeking higher levels of Multi-Site, Customers
testing complex RF devices (such as Power Amplifiers which may require the NI RF Sub-System), and
Customers testing devices (such as Advanced CMOS Image Sensors) that require the addition of Third-
Party Hardware (to be contained within a larger test head center cavity). Fortunately all STS (T1, T2, and
T4) share the same Load Board - so migrating devices between STS is fully supported.
The open platform architecture of the STS is comprised of Fixed Costs, and Variable Costs. Variable Costs
are dominated by expense associated with the modular PXI Instruments contained within the open slots
(available within each enclosure bay). T1 has one bay, T2 (see above) has two bays, and T4 has four bays.
Fixed Costs include the STS Test Head Enclosure, Docking / Interface Hardware, PXI Chassis (in each bay),
Chassis Controller(s), and STS Software suite (TestStand Semiconductor Module, TestStand & LabVIEW).
The factory footprint of the T1 and the T2 is the same & very compact (approximately ~ 600 square-
inches). The factory footprint of the T4 is also compact (approximately ~ 1,000 square-inches).
STS Customers configuring optimized Production Test configurations tend to favor the T2 enclosure.
Especially in cases when the single bay T1 is very full, and only a few expansion slots remain open. The
economics for this decision is quite straightforward:
A 25% higher Acquisition Cost (T2 vs. T1) doubles (200%) the STS platform architecture headroom.
The slightly higher Fixed Cost of the T2 is well off-set by the benefits of Time-to-Revenue considerations.

2. This is especially true for the STS which are typically much lower Capital Cost to buy (than Legacy ATE),
much smaller Facilities Footprint, and many Customers report higher Throughput achieved with the STS
(than Legacy ATE) due to a very modern and modular PXI architecture. One STS competitive advantage is
a substantially lower Cost-of-Test (COT). But what should not be overlooked is the substantial (Time-to-
Revenue) get to market advantage of being able to use the same (ATE hardware + software) platform =>
Lab Characterization => NPI => Sample Test => Production Test.
In many cases, Product Engineers and Test Engineers (over time) may require the addition of PXI
Instruments to test a newer wider variety of target Product Family devices. STS customers have reported
that it is very important to not over constrain the available PXI Instruments chosen because of a concern
that a limited number of open slots may be available (for example with a T1) to address new device
roadmap testing challenges.
Providing Product Engineers and Test Engineers too few PXI instruments (or older and dated PXI
instruments) can have negative consequences for the effectiveness & productivity of these engineers to
get new silicon properly Characterized, for making important New Product Introductions (NPI) decisions,
and for accelerating the Release-to-Production of high Quality and high Throughput production test
cells. The marginal revenue benefits (getting new silicon to market sooner), may Trump marginal ATE
capital equipment acquisition savings (expected by using a single bay STS T1 enclosure).
In Semiconductor Test small hands might be helpful for manually loading and unloading devices during
Lab Characterization. But for Production Test the size of your test head enclosure is an important
consideration.
Size Matters.