Die-attach is the term reserved for processes where the face of a die is attached to a substrate by a single joint.

Features & Benefits

The joint may be of polymer (adhesive), metal-filled polymer, or in the form of solder derived from a preform, solder paste, or solder wire.
Die-Attach Wire

Die-Attach Wire

Indium Corporation's Die-Attach Wire (or SSDA [soft solder die-attach] wire) is a fluxless solder wire used to effect die-attach. SSDA grade wire will result in higher yields of an improved quality product with fewer interruptions in production.

Key Performance Needs
  • Ultralow oxide (wire surface and in wire)
  • High alloy purity
  • Precise and consistent wire diameter
  • Tight alloy chemistry control
Die-Attach Wire Diagram
Die-Attach Paste

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
Die-Attach Paste Diagram
“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
BiAgX®75 Solder Paste

BiAgX®75 is a high-melting, lead-free solder paste technology that serves as a drop-in replacement for the high-Pb solder pastes used in many high-reliability, die-attach, and electronics assembly applications.

“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.

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Alloy Metal Content Mesh Size Particle Size Recommended Needle Size*
88% Type 3 25 to 45
(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
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Test Result
J-STD-004 (IPC-TM-650)  
Flux Type Classification ORL0
Presence of Halide
Fluoride Spot Test
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
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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.

  • 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
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