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two or three times. If we remove one test
insertion, then by definition you are not
going to be doing any tests four times
over. In general, the Venn diagram regions
in Figure 6 will move away from each
other, resulting in less overlap.

Summary
Several conclusions arise regarding this
overview of the shift-left concept. First,
test content itself is an incredibly valuable
resource, and it is a resource that we can
move around. For example, an f MAX test can
be done at the wafer level, it can be done at
final test, or it can be done at system-level
test. What we need to look at is where is the
best place for us to do this important test for
each device.
If you are shipping KGD, prior to
Figure 5: For a multi-chip module, the shift-left strategy reduces manufacturing cost 28% and increases parts shipment you will need to screen for obvious
shipped by 37%.
failures, confirm functionality at temperature
extremes, find assembly-induced problems,
and perform speed and power binning, full
built-in self-test (BIST) and scan, high-speed
I/O test, and fuse blowing.
In addition, this overview of shift left
reconfirms what may be obvious to anybody
in the industry: more testing sooner will
increase the quality of your product for
a small incremental cost increase. You
will have to pay for test in any event, and
making that payment sooner will allow you
to: 1) save packaging cost, 2) reduce the
number of good parts scrapped because of
another part’s problem in a shared multi-
die assembly, and 3) it will allow you to
Figure 6: The move from: a) (left) a traditional test flow to b) (right) a shift-left test flow eliminates one test end up with an ultimately lower cost, more
insertion and reduces over-testing.
profitable product.
Active thermal control (ATC) is feasible packaged device test, boot-up tests, and
at the KGD test step, however, using a fuse-blowing, will shift left and can be Biography
system such as the Advantest HA1000 performed on either a traditional final-test Dave Ar mstrong is Director of
die-level handling and probing system for system or on a system-level-test system. Business Development at Advantest
singulated die testing. What is required at this step is a system- America, Inc., San Jose, CA, and is
In addition to ATC (with junction- focused environment with system-focused also Chairman of the Test Technology
temperature feedback per the device code that can boot up the device under test Working group for the Heterogeneous
under test [DUT]), a KGD tester is able and run its firmware and software. A key Integration Roadmap. Prior to Advantest,
to take on final-test functions such as at- benefit of the shift left flow is that it can he spent over two decades in HP/
speed testing, which will require high- eliminate one test insertion. One less test Agilent’s IC test group, and before that
speed instruments, high-power supplies, insertion means one less test cell—one he worked in the semiconductor industry
high-frequency probes, and high current- less handler—bringing about significant in areas of IC and system design,
carrying-capacity probes. financial benefits. product/yield engineering, as well as
As KGD testers take on final-test A related issue the indust r y is test engineering. He has degrees in
functions, some traditional KGD tests, contending with is over-testing. If today Electrical, Computer, and Environmental
including two-temperature testing, we have wafer test, KGD test, final test, Engineering from the U. of Michigan.
will shift left to wafer test. And finally, and system-level test, the reality is that a Email d.armstrong@advantest.com
system-level test functions, including lot of tests are run four times, or at least

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