Spherical & Flake, Paste Grade
Paste-grade Cu powder 0.5-10µm spherical and 5-25µm flake, O < 0.3-0.5%, surface-treated, tap density > 4.5. Silver-free metallization for MLCC, LTCC, solar and printed electronics.
QUICK ANSWER
Paste-grade conductive copper powder — spherical cuts (0.5-10 µm) for fired and polymer pastes, flake for polymer thick-film conductors — is the base material of copper metallization pastes for MLCC external electrodes, LTCC, solar cell plating, and printed electronics. As silver prices push manufacturers toward copper metallization, paste-grade copper has become the fastest-growing conductive powder family.
Copper paste technology solves copper's oxidation problem in two ways: nitrogen-fired pastes (MLCC termination, LTCC) sinter copper in inert atmosphere to full conductivity, and polymer thick-film pastes (membrane switches, RFID antennas, flexible circuits) use flake copper that cures at low temperature with anti-oxidation chemistry. The powder specification differs sharply by route — fired pastes need spherical, sub-micron-to-micron cuts with narrow distribution and low oxygen; polymer pastes need flake with high aspect ratio for percolation at 60-70% loading. Formulators buy on tap density, BET surface, oxygen content, and fired/cured conductivity data per lot.
MATERIAL DATA
Lot-level controls focus on the chemistry, particle characteristics, and process values that influence manufacturing consistency and finished-part performance.
| Element | Content | Performance Role |
|---|---|---|
| Copper (Cu) | > 99.8 wt% | Conductivity base — purity tracks resistivity |
| Oxygen (O) | < 0.3 wt% (spherical), < 0.5% (flake) | Oxidation control — the core copper challenge |
| Surface treatment | Fatty acid / proprietary | Anti-oxidation and paste dispersion |
| Carbon + moisture | < 0.2 wt% combined | Firing and shelf-life control |
| Impurities (Fe, Pb, others) | < 0.1 wt% combined | Electronic-grade panel |
Final limits can be aligned with the agreed purchase specification.
APPLICATIONS
MLCC and LTCC manufacturing anchors the fired-paste stream: every base-metal-electrode MLCC (which is nearly all of them — trillions per year) terminates with copper paste fired in nitrogen, and LTCC modules for RF and automotive use copper conductors throughout. Paste formulators and captive electronics manufacturers buy spherical copper on fired conductivity, shrinkage match to their dielectric, and oxygen content — qualification takes months, then volumes run steady for years. Copper's cost advantage over silver is structural, and the metallization shift is one-directional.
Printed and flexible electronics drive the polymer-paste stream: RFID antennas, membrane touch switches, flexible heaters, and wearable circuits print copper flake pastes that cure below 150 °C onto PET and paper; solar cell metallization increasingly trials copper plating and copper paste to escape silver cost; and conductive adhesives fill copper for die-attach and shielding. Each application buys on cured conductivity per unit cost — copper's unbeatable position against silver wherever oxidation is managed.
ELECTRONIC PASTE & CONDUCTIVE METAL POWDERS
CUSTOM SUPPLY
We supply spherical paste-grade copper in 0.5-10 µm cuts with surface treatment, certified oxygen and tap density, plus flake grades for polymer thick-film formulation. Fired-shrinkage data on standard test pastes, anti-oxidation treatment options, and co-development with your firing profile or resin system are available. Silver-free by design — no quota exposure, ships freely.
We supply spherical paste-grade copper in 0.5-10 µm cuts with surface treatment, certified oxygen and tap density, plus flake grades for polymer thick-film formulation.
Fired-shrinkage data on standard test pastes, anti-oxidation treatment options, and co-development with your firing profile or resin system are available.
Silver-free by design — no quota exposure, ships freely.
MATERIAL COMPARISON
| Comparison Point | This Product | Silver Paste |
|---|---|---|
| Metal cost | ~1% of silver per kg | Benchmark — Ag price exposed |
| Bulk resistivity | 1.68 µΩ·cm | 1.59 µΩ·cm — marginally better |
| Oxidation | Must be managed — the core challenge | Oxide conductive — forgiving |
| Electromigration | Resistant | Migrates — reliability risk |
| Firing atmosphere | Nitrogen required | Air-firable |
| Trend | Rapidly displacing Ag in volume apps | Retreating to premium niches |
TECHNICAL FAQ
Need a different chemistry, particle range, or processing route? Our material team can review the requirement and supply window.
Three layers: low-oxygen powder with certified analysis, surface treatment (fatty acid or proprietary films) that survives printing but burns off clean in firing, and inert-flushed sealed packaging. Polymer pastes add anti-oxidant chemistry in the vehicle.
1-3 µm spherical with narrow distribution and high tap density — shrinkage must match the capacitor dielectric's firing curve. We supply fired-shrinkage data on standard test vehicles.
Standard copper pastes cannot — they need nitrogen. Air-firable copper pastes exist using glass encapsulation chemistry; we supply the specialty spherical powder for those formulations.
3-10 µΩ·cm cured depending on flake grade, loading, and cure — roughly 3-6x bulk copper resistivity, sufficient for antennas, switches, and heaters. Flake aspect ratio is the main lever.
No. Copper conductive powders ship without licensing — and unlike silver, carry no quota or state-trading exposure.
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