Tech Briefs Magazine - June 2024 - 15

T
he size and competitiveness of
the mobile phone industry has
driven investment and innovation
in many industries, from
imaging to software to even metallurgy.
Few industries have been as affected as
the semiconductor market, where demand
for higher performance in smaller
packages has been unrelenting for few
decades. Last year, Apple released its
latest iPhones, some powered by its new
A17 Bionic chips, built on Taiwan Semiconductor
Manufacturing Co's (TSMC)
new 3-nm manufacturing process. Apple
is reportedly buying up everything
that TSMC can manage to make. These
chips are reportedly smaller, faster, cooler,
more power-efficient than their 5-nm
predecessors. According to Apple, each
chip features 19 billion transistors, some
so small that their elements are only 12
silicon atoms wide.
The same pressures extend to printed
circuit board (PCB) manufacturing: Apple
will reportedly switch to using resin
coated copper (RCC) foil for their new
PCB material, allowing the company to
make them even thinner. This will be
challenging for manufacturers, as RCC
foil is very delicate and especially vulnerable
to heat and pressure in the laminating
process.
It's not enough to be innovative -
you must return a profit. New reporting
from The Information describes the favorable
terms that Apple has secured to
keep its costs down: in return for the
huge orders TSMC has to absorb the
costs of defective processor dies. So
while fabs like TSMC are touting their
competitiveness with ways to develop
smaller node processes to reduce chip
size and lower power consumption, they
will have challenges on the quality side.
Automated Optical Inspection
for PCB Quality Inspection
For many companies, quality control
is the major bottleneck in the PCB manufacturing
chain, including reliability
testing and reworking defective PCBs.
Improving the speed and efficacy of
quality control can significantly increase
the production yield and throughput,
reducing manufacturing costs and waste.
Most PCB manufacturers use automatic
optical inspection (AOI) to monitor
defects in their printed circuit boards.
This delivers strong results when there
are defects in the soldering, connections,
pads, and traces on printed boards.
AOI also proves very useful for the early
detection of problems that happen
during assembly, such as shorts, open circuits,
thinning soldering, scratches on
traces, and more. In particular, scratches
can be " fatal " to a board, changing its
electrical properties and causing a total
malfunction of the completed product.
AOI has the advantage of being included
directly at the end of the PCB
production line, before lamination and
etching, detecting possible defects earlier
than other methods. Imaging systems
capture high-resolution images, with resolution
down to a few microns, and then
comparing them to images of a 'perfect'
model board (also known as the " golden
board " ) or with an image database of
both acceptable and defective samples.
Other than performing tests on the
PCB under assembly, the AOI method
can monitor the manufacturing process
itself. Pick-and-place machines can respond
to detected defects in real-time,
correcting assembly defects like component
misplacement and misalignment.
Moving Past the Conventional
Toward Artificially Intelligent
Imaging
Still, with the demand for smaller,
higher-performance parts, the resulting
complexities and subtleties in material
faults means that traditional manual inspection
or rule-based imaging may simply
not be up to the task. One semiconductor
OEM needed to detect a variety of
subtle defects on PCB components, including
breakage, abrasion, contamination,
fragments, and air bubbles. However,
using traditional rule-based image
processing was not providing the accuracy
they required. They were facing an increase
in defective parts that went undetected
in their existing process, driving
up costs. They needed a new solution.
To overcome these obstacles, the
OEM decided to explore machine
learning to meet their accuracy requirements
for detecting defects on
PCBs and their components. They
chose Teledyne's Sapera AI inspection
software suite. The Sapera AI software
Tech Briefs, June 2024
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Tech Briefs Magazine - June 2024

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