Page 34 - Chip Scale Review_November-December_2023-digital

well developed. Probe impedance probe’s dimensions while keeping Figure 3. The simulations show that
control on the other hand, is not well the same mechanical behavior among probes enlarged at +20% and +40% in
defined; it is also highly dependent on probes of different dimensions that CS are the best optimized case for a
the bump pattern. Designing a probe are inside the same probe head. This target impedance of 85Ω.
with a target impedance is highly technology improvement allows the Fa rad ay’s c a ge concept . T he
challenging as the probe dimensions fine tuning of the HSIO probe cross cross-section optimization concept
must meet both signal integrity and section (CS), which varies the gap has two main limitations: 1) physical
mechanical requirements. The probe between each probe with the building c o n s t r a i nt s b a s e d o n t h e p r ob e
technology we are presenting in this block to match the target impedance. he a d me ch a n ical st r uct u re; a nd
article allows the modification of a CS ch a nge s ca n b e ob se r ve d i n 2) a probe’s coupling effect that
contributes to cross talk. Although
performance improvement can be
seen with the probe cross-section
optimization, which leverages new
technology that allows larger cross-
s e c t i o n va r i a t i o n , t h e p r i m a r y
limitation for the probe dimension
is due to the keep-out zone in the
LEADERS IN placeholder design rule constraint.
E a c h p r o b e i s i n s e r t e d i n a
MICRO DISPENSING placeholder (holes). As the cross-
s e c t i o n a l a r e a o f t h e p r o b e s
TECHNOLOGY i nc rea se s, t he d i me n sion of t he
holes will increase at the same time.
To maintain structural integrity of
SMALL REPEATABLE VOLUMES
ARE A CHALLENGE, BUT NOT the probe head, the hole clearance
IMPOSSIBLE IF YOU HAVE BEEN bet ween the closest probes must
CREATING THEM AS LONG AS WE HAVE. comply with the mechanical design
rule. Any design rule violation will
result in the probe head guide plate
cracking during test operation. With
TO DO IT WELL, a n e n la rge me nt of +20 % c r o s s -
WE PROVIDE THREE THINGS: sectional area, structural integrity
ca n st ill be met. But w it h more
than +20% enlargement, structural
integrity will be impacted as seen in
Dispensing Expertise in a variety of microelectronic Figure 4. To achieve signal integrity
packaging applications. i mprovement solely t h roug h t he
probe’s cross-sectional area increase
Feasibility Testing & Process Verification based is not sufficient.
on years of product engineering, material flow testing Another limitation on the probe’s
and software control. dimensions arises from concer ns
about cross talk. As the probe’s cross
Product Development for patented valves,
dispensing cartridges, needles, and accessories. section increases by +20% and beyond
(Figure 5) it reduces the impedance
p e a k , t h e r e b y i m p r o v i n g t h e
ret u r n loss (R L). T he cross-tal k
performance, however, is decreased
compa re d t o t he st a nd a rd c ross
Our Micro Dispensing product line is proven and trusted by section. Further optimization has
manufacturers in semiconductor, electronics assembly, medical b e e n r e q u i r e d t o i m p r o v e R L ,
device and electro-mechanical assembly the world over. insertion loss (IL) and cross-talk
www.dltechnology.com. performance all together. Various
design of experiment (DOE) trials
were conducted to find a balance
216 River Street, Haverhill, MA 01832 • P: 978.374.6451 • F: 978.372.4889 • info@dltechnology.com
among the three trade-offs.

32 Chip Scale Review November • December • 2023 [ChipScaleReview.com]
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