Die-Attach Paste

Although there are four major processes for die-attach, solder-based processes are still the most popular, as they provide high reliability with ease of processing. Indium Corporation’s die-attach solder paste is typically a dispensable, high melting-point solder paste, which is reflowed in forming gas (H₂N₂ mix).

Key Performance Needs

• Low voiding in reflow
• Long dispense life
• No tailing
• No separation
• Bubble-free packaging
• Residue-free cleaning or residue compatible with overmolding process

“Power-Safe” NC-SMQ®75 Die-Attach Solder Paste

NC-SMQ®75 is the only solder paste suitable for use in non-cleaned clip-bonded applications in power semiconductor die-attach assemblies. It has:

• Superior wetting capabilities compared to most low residue formulations
• Trouble-free probe testing
• No-residue appearance

“Power-Safe” NC-SMQ75 Die-Attach Solder Paste

Indium Corporation’s “Power-Safe” NC-SMQ75 is an ultra-low residue, halogen-free, die-attach solder paste that leaves a completely benign, almost undetectable residue of approximately 0.4 weight percent of paste.

Alloy	Metal Content	Mesh Size	Particle Size	Recommended Needle Size*
Sn10/Pb88/Ag2 Sn5/Pb92.5/Ag2.5 Sn5/Pb95 Sn5/Pb85/Sb10	88%	Type 3	25 to 45 microns (Type 3)	20 gauge*

NC-SMQ75 is the only solder paste suitable for use in non-cleaned clip bonded applications in power semiconductor die-attach assemblies.

It is designed for reflow in a nitrogen or forming gas atmosphere of 100 ppm oxygen or less and can survive the high temperatures associated with both high-lead (Pb) and gold-tin alloy reflow.

Bellcore and J-STD Tests & Results

Test	Result
J-STD-004 (IPC-TM-650)
Flux Type Classification	ORL0
Presence of Halide Fluoride Spot Test	Pass
Elemental Analysis	Halide-Free
Post Reflow Flux Residue (ICA Test)	0.4% of solder paste
Corrosion	Pass
SIR (Post Clean)	Pass
Acid Value (Typical)	31.5

Test	Result
J-STD-005 (IPC-TM-650)
Typical Solder Paste Viscosity (Pb92.5/Sn5/Ag2.5. Type 3. 88%)
Brookfield (TF 5 rpm)	230 kcps
Brookfield (R7 10 rpm)	170 kcps
Slump Test	Pass
Solder Ball Test	Pass
Wetting Test	Pass
Standard Metal Load	88%

All information is for reference only. Not to be used as incoming product specifications.

Features:

• Ultra-low post-reflow residue <0.5%w/w of solder paste
• “Power-Safe” residue compatible with overmolding compounds without delamination
• Halogen-free
• Consistent dispensing deposit size without clogging (Powder types 3, 4, 5, 6)
• Airlessly syringe-packed (bubble-free)
• Wide range of alloy compatibility
• Reflow up to 400°C
  • Low oxygen or forming gas needed (<100ppmO2)
• Low-voiding for smaller die (< 6mm x 6mm)
  • Meets <5% single, <10% total industry voiding standard
• Good wetting with common metal finishes