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The Ecopack working group has selected 3 technologies
(NiPdAu, Pure Sn and SnAgCu Ball) to match the different technical and
quality requirements and cover the full spectrum of packages. The Conversion
program applies both to internal and subcontractor production lines.
NiPdAu:This technology is well known on the market and several
billions of parts have been already shipped by the semiconductor industry.
ST already qualified it in 1996. It is also known as PPF (Pre-Plated
Frame). The NiPdAu technology is the preferred choice of ST each time
it is technically feasible. Beside the change of lead frame, a change
in materials (glue and molding compound) may occur to meet the higher
soldering temperature constraints required for lead-free soldering.
The NiPdAu technology will be used for most of Signal SMD packages:
SO, TSSOP, L/TQFP with few exceptions such as SMD packages with soft
solder die attach, PLCC (due to the particular shape of the leads),
TSOP (alloy 42), few L/TQFP, Exposed pad packages.
Pure Tin (Sn): This technology is also a very common Lead-free
solution used by semiconductor manufacturers. There are 2 sub-processes:
Dipping and Post-plating (Matt Sn). This technology is selected by
ST for all other leadframe-based packages which are not eligible for
NiPdAu.
The Pure Tin technology will be used for: Power SMD packages, Insertion
packages, PLCC, TSOP.
SnAgCu ball: This ternary alloy is an improved composition,
derived from SnAgCu alloy. SAC + is the material chosen for the balls
of all “Ball Grid Arrays” (BGA) and balls and bumps of
Flip-Chips (currently using PbSn). Its melting point is 217°C
and its composition close to the one of the most common solder pastes.
It is the preferred alloy selected by the large majority of semiconductors
companies and subcontractors.
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Packages
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Pb-Based
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Lead-Free
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Lead frame
based
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SnPb
Dipping
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Tin (Sn)
Dipping
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SnPb
Post plating
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Matte Tin
(Sn)
Post-plating
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NiPdAu
Pre-plating
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SnBi
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Packages
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Pb-Based
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Lead-Free
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Ball Grid
Array
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SAC+
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Bumps for
FlipChip
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SnAg
Gold bumps
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Die bonding in power packages
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Exempted
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Glass sealing in frit seal packages
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Alloys used in
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Packages
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ST Production lines
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Subcontractors lines
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Power SMD
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Matte Sn post plated coating
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X
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Signal SMD
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NiPdAu pre plated coating
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Sn, SnBi post plated coating
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Matte Sn post plated coating
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Insertion package
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Matte Sn post plated coating
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Sn, SnAgCu coating by dipping
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BGA
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SAC+ solder balls
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SAC+ solder balls
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(*) SnAgCu metallurgy or its derivatives
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Packages
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Alloys
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ST Production lines
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Subcontractors lines
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Matte Sn post plated coating
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Power SMD
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X
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Insertion package
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Insertion package
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Signal SMD
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Signal SMD
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NiPdAu pre platted coating
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Signal SMD
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X
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SnBi post plated coating
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X
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Signal SMD
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Sn coating by dipping
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Insertion package
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Insertion package
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SnAgCu coating by dipping
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X
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Insertion package
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SAC+ solder balls
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BGA
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BGA
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