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mounting die and the pocket side spray coater and high depth of focus throughput of the flip-chip mounting
walls. Because the chemical solution’s exposure system need to be used machine by optimizing the design
silicon concent ration affects the for attaining a three-dimensional rule for space/distance between the
etching rate, this information is used s t r u c t u r e l i t ho g r a p h i c a l l y. I n mounting die and the pocket side walls
to set the condition of pocket depth t h e b a ck- e n d p r o c e s s f low, d ie in consideration of the machine’s
control. By using the feedback system mounting and wafer over-molding accuracy and the self-aligning effect
with respect to silicon concentration, are key technologies to realize this during reflow. Compression molding
the etching depth was stabilized and package. It is important to select a equipment is also indispensable in the
the process capability, Cpk, improved low-damage, high-speed f lip-chip wafer over-molding process. It is also
significantly from 1.00 to 2.54. mounting machine for die mounting. important to select the proper resin
In addition to the above steps, a Fu r t h e r m o r e , we m a x i m i z e t h e for wafer warp control. To assure
quality, package-level reliability
testing is completed using the basic
flow. Board-level reliability testing
was also completed on the products
that are assembled and mounted on the
printed circuit board (PCB). The test
conditions and the results are shown
in Table 1. All reliability test items in
LEADERS IN the table also passed.
MICRO DISPENSING Dual-die mounting technology
T he advant age of the dual- die
TECHNOLOGY mounting technology is that two dies
are mounted in a stack and electrically
connected without the costly through-
SMALL REPEATABLE VOLUMES silicon via (TSV) technology. Figure
ARE A CHALLENGE, BUT NOT 4 shows the package structure and
IMPOSSIBLE IF YOU HAVE BEEN an example of the dual-die mounting
CREATING THEM AS LONG AS WE HAVE. package with the control IC (using
LSI manufact uring technologies)
and memory. Owing to structural
constraints, the die that is mounted on
TO DO IT WELL, the lower side must be smaller than
WE PROVIDE THREE THINGS: the one mounted on the upper side.
The X-ray photograph (Figure 4)
shows interconnects from these dies
up to the external terminals through
the Cu routing and solder bumps.
Dispensing Expertise in a variety of microelectronic During our product qualif ication
packaging applications. testing, we confirmed that there is
no problem with device performance
Feasibility Testing & Process Verification based because of the package stress, and no
on years of product engineering, material flow testing issue with the application’s operation
and software control. either. This package has the same
key processes as used for single-
Product Development for patented valves, die mounting, but has challenges
dispensing cartridges, needles, and accessories. specific to the dual-die packaging
structure. So, by solving the specific
challenges associated with dual-die
mounting, we were able to achieve a
new packaging technology.

Our Micro Dispensing product line is proven and trusted by Necessity of optimized design rules
manufacturers in semiconductor, electronics assembly, medical for 3D structures
device and electro-mechanical assembly the world over. A s n o t e d a b ove , t h e d u a l- d ie
www.dltechnology.com. m o u nt i n g p a ck a ge h a s s p e c i f ic
challenges. One such example is
216 River Street, Haverhill, MA 01832 • P: 978.374.6451 • F: 978.372.4889 • info@dltechnology.com the optimization of design rules. In
the initial layout, we observed the

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