Page 63 - ChipScale_Mar-Apr_2021-digital

Figure 8: Chemical reactions to produce resins for the: a) (left) original PID, and b) (right) new PID.
was performed. First, the new PID
(10µm thick) was laminated on a 4”
wafer by vacuum lamination. After
the lamination, a UV dose of 1.0J/
2
cm was applied by an i-line exposure
tool. Then, the PID was thermally
cured at 180°C for 60 minutes. On
top of the PID, Cu patterning was
fabricated by SAP as follows: a Ti LEADERS IN
and Cu seed layer (50nm and 300nm,
respectively) was first deposited with MICRO DISPENSING
a sputtering tool. Photoresist was
then coated on top of the seed layer TECHNOLOGY
by using a spin coating process at
5µm thickness. The photoresist layer SMALL REPEATABLE VOLUMES
was patterned with a photomask with ARE A CHALLENGE, BUT NOT
a L/S = 2/2µm comb pattern, and IMPOSSIBLE IF YOU HAVE BEEN
then developed. After the photoresist CREATING THEM AS LONG AS WE HAVE.
patterning, electrolytic Cu plating
was conducted to build 4µm-thick Cu
patterns. Photoresist was then stripped
off with organic solvent, and the seed TO DO IT WELL,
layer was etched out. As a result, WE PROVIDE THREE THINGS:
L / S = 2 /2 µ m C u p a t t e r n s w e r e
successf ully for med without any
r e s i d u e of p ho t o r e s i s t o r s e e d
layer (Figure 7). This f ine-pitch
Cu patterning can be achieved by Dispensing Expertise in a variety of microelectronic
improved solvent resistance of the packaging applications.
new PID, which made it possible
t o s ele c t t h e l a t e s t pho t o r e si s t Feasibility Testing & Process Verification based
for patterning. on years of product engineering, material flow testing
C u m i g r at i on r e s i s t a nc e for and software control.
high BHAST reliability. Material
design for better BHAST reliability Product Development for patented valves,
at fine-pitch L/S was investigated by dispensing cartridges, needles, and accessories.
reducing chloride ion content in the
PID material. Cu migration under
BHAST conditions is catalyzed by
the presence of chloride ion in the
system. A Cu ion is stabilized by the
presence of a chloride ion, which Our Micro Dispensing product line is proven and trusted by
reduces the activation energy of Cu manufacturers in semiconductor, electronics assembly, medical
ion dissolution from the anode side, device and electro-mechanical assembly the world over.
and a redeposition of Cu metal at the www.dltechnology.com.
cathode side. Finally, as a result of Cu
diffusion, Cu migration occurs. As 216 River Street, Haverhill, MA 01832 • P: 978.374.6451 • F: 978.372.4889 • info@dltechnology.com
the spacing between the Cu wirings

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