ST（意法半导体）无铅解决方案

   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.

Packages		Pb-Based	Lead-Free
Lead frame based		SnPb Dipping	Tin (Sn) Dipping
		SnPb Post plating	Matte Tin (Sn) Post-plating
			NiPdAu Pre-plating
			SnBi

Packages	Pb-Based	Lead-Free
Ball Grid Array		SAC+
Bumps for FlipChip		SnAg Gold bumps
Die bonding in power packages		Exempted
Glass sealing in frit seal packages

Alloys and packages

Alloys used in Packages ST Production lines Subcontractors lines Power SMD Matte Sn post plated coating X Signal SMD NiPdAu pre plated coating Sn, SnBi post plated coating Matte Sn post plated coating Insertion package Matte Sn post plated coating Sn, SnAgCu coating by dipping BGA SAC+ solder balls SAC+ solder balls

(*) SnAgCu metallurgy or its derivatives

	Packages
Alloys	ST Production lines	Subcontractors lines
Matte Sn post plated coating	Power SMD	X
	Insertion package	Insertion package
	Signal SMD	Signal SMD
NiPdAu pre platted coating	Signal SMD	X
SnBi post plated coating	X	Signal SMD
Sn coating by dipping	Insertion package	Insertion package
SnAgCu coating by dipping	X	Insertion package
SAC+ solder balls	BGA	BGA