Via-Fill Conductive Copper Paste: How JL-CS-F01 Solves Through-Hole Filling Challenges in Semiconductor Packaging
2026-07-09
A single-component via-fill resin engineered for low CTE, high conductivity, and process flexibility.
Industry pain points: why do via-fill materials keep failing?
In advanced semiconductor packaging, PCB via-filling, and microelectronic interconnection processes, engineers repeatedly run into the same set of problems:
Cracking failures
Conventional fill materials often have a high coefficient of thermal expansion (CTE), making them prone to micro-cracking during thermal cycling or 260°C reflow — compromising the conductive path and causing batch-level yield loss.
Inconsistent conductivity
Some conductive pastes cure with uneven or elevated resistivity, degrading signal integrity and overall thermal dissipation.
Weak adhesion
Poor bonding between the fill material and via wall substrate leads to delamination or peeling after repeated thermal cycling.
Compliance risk
Halogen-containing materials struggle to meet RoHS and halogen-free requirements, which can jeopardize export certification and customer qualification.
Limited process compatibility
Materials restricted to a single application method (dispensing-only or printing-only) force costly line reconfiguration when switching processes.
These issues usually trace back to a mismatch between the resin's thermal expansion behavior, its curing chemistry, and the conductive filler system — a detail that's easy to overlook during material selection but ultimately determines production yield.
JL-CS-F01: solving via-fill challenges at the material level
Developed by Joinspire, JL-CS-F01 is a single-component via-fill conductive resin engineered specifically to address the pain points above:
✓
Low CTE, excellent dimensional stability — CTE α1 (below Tg) of 40-50ppm, CTE α2 (above Tg) of 110-130ppm, with total expansion at 260°C of only 1.5-2.0%, significantly reducing thermal-stress-induced cracking.
✓
High electrical conductivity — Resistivity below 8×10⁻⁵ Ω·cm, suitable for high-density interconnect signal transmission requirements.
✓
High thermal conductivity — Thermal conductivity of 124 W/m·k, improving heat dissipation, particularly valuable for power device packaging.
✓
Excellent adhesion — 100/100 rating under cross-hatch + 3M tape testing, minimizing long-term delamination risk.
✓
Halogen-free, environmentally compliant — Meets mainstream international electronics manufacturing environmental standards.
✓
Low-temperature curing — Fully cures at 170-190°C in 60-90 minutes, compatible with a wide range of temperature-sensitive substrates and production line cycle times.
✓
Dual process compatibility — Works with both dispensing and printing processes, offering flexibility across different production line setups without requiring equipment changes.
Applications
1
Advanced semiconductor packaging via-fill (TSV/TGV-type applications)
2
PCB blind/buried via conductive fill
3
Power module thermal pathway construction
4
Microelectronic device interconnection and structural reinforcement
5
Chip-level packaging gap-fill and structural support
Key technical specifications
| Property | Value | Test method |
| Appearance | Light brown | Visual |
| Viscosity | 5-30 Pa.s | @20rpm, Viscometer |
| Solid content | 100% | TGA |
| Resistivity | <8×10⁻⁵ Ω·cm | 4-point probe method |
| Thermal conductivity | 124 W/m·k | Laser flash method |
| Glass transition temperature (Tg) | 160°C-190°C | TMA |
| CTE (below Tg) α1 | 40-50ppm | TMA |
| CTE (above Tg) α2 | 110-130ppm | TMA |
| Total expansion at 260°C | 1.5-2.0% | TMA |
| Adhesion | 100/100 | Cross-hatch + 3M tape method |
| Curing condition | 170-190°C, 60-90min | Atmosphere: N₂ or air |
| Storage temperature | -10~10°C | — |
| Shelf life | 3 months | — |
Usage & process guidelines
Storage
Store at -10~10°C, protected from light, and avoid high-humidity environments.
Thawing
After removal from cold storage, let the material sit at room temperature (25°C) for at least 4 hours to fully thaw, then wipe off any surface moisture before use.
Process application
Compatible with dispensing and printing processes for via-fill, gap-fill, and similar applications. Cure in an oven at 170-180°C for 60-90 minutes under nitrogen or air atmosphere.
FAQ
What packaging processes is JL-CS-F01 suitable for?
It's designed for advanced semiconductor packaging via-fill, PCB blind/buried via conductive fill, and power module thermal pathway construction, and is compatible with both dispensing and printing processes.
How does copper paste compare to traditional silver conductive paste?
Copper paste delivers strong conductivity and thermal performance at a lower material cost than silver-based alternatives, making it well-suited for cost-sensitive, high-volume production while still meeting demanding electrical and thermal requirements.
Does this product meet environmental compliance requirements?
Yes — it is halogen-free and meets mainstream environmental compliance standards for electronics manufacturing.
Is the cured material prone to cracking?
The low CTE and strong dimensional stability, combined with the recommended curing profile (170-190°C, 60-90 minutes), significantly reduce cracking risk during thermal cycling and reflow processes.
What is the product's shelf life?
3 months when stored at -10~10°C, protected from light. Purchasing planning should account for batch-based inventory turnover.
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