Popular custom 94v0 high flame retardant multi-layer printed circuit board applied to consumer electronics products

1、 Process technology: the core obstacle to multilayering

1. Limitations of the substrate

Paper based structural defects: 94V0 is made of cotton fiber paper and flame-retardant epoxy resin as the core, with low mechanical strength (bending strength<200MPa), and high temperature and pressure (180 ℃/400psi) during lamination can easily cause delamination and deformation.

Drilling difficulties: Only mechanical drilling (aperture ≥ 0.4mm) is supported, and laser drilling of micropores is not possible (high risk of paper-based carbonization), which restricts high-density interconnection.

Laminated challenge: Water absorption rate>0.5%, baking at 120 ℃ for 2 hours to control humidity before lamination, there is still a risk of board bursting.

2. Surface treatment and reliability bottleneck

Limitations of pore metallization: Chemical deposition of copper with a depth to diameter ratio of ≤ 6:1 (FR-4 can reach 8:1), weak adhesion between pore walls, and easy occurrence of pore copper fracture.

Insufficient temperature resistance: Tg ≈ 105 ℃, strict temperature control is required during lead-free soldering (peak value 260 ℃) (tin furnace ≤ 285 ℃/5 seconds), otherwise the copper foil will bubble.

Conclusion: 94V0 is essentially a single panel material, and multi-layer production requires the use of fiberglass substrates such as CEM-3 or FR-4.

2、 Core advantage: The ultimate balance between flame retardancy and economy

Despite the limitations of multilayering, 94V0 has significant advantages in single/double-sided panels:

Advantage Dimension 94V0 Performance Comparison FR-4
The cost of sheet metal is ¥ 20-30/㎡, which is 60% lower than FR-4 and suitable for large-scale stamping (monthly production>20000 ㎡)
Flame retardant UL 94 V-0 certification (10 second self extinguishing) at the same level as FR-4, meeting basic safety regulations
Environmentally friendly paper-based material is biodegradable, with a copper recovery rate of over 90%. Glass fiber is difficult to recycle and causes higher pollution
Delivery speed: urgent sample delivery within 24 hours, batch cycle of 3-4 days, 50% faster than FR-4 multi-layer board

3、 Application area: Low cost and reliable scenarios

The advantages of 94V0 are concentrated in low-frequency, low complexity, and high cost sensitive fields:

1. Consumer electronics (accounting for 70%)

Power adapter: Mobile phone charger control board (cost<¥ 1/piece), 1.6mm thickness, no deformation after passing through the tin furnace.

Home appliance control board: electric fan timer, remote control (double-sided wiring simplified jumper).

2. Industrial control (accounting for 25%)

Relay module: OSP processing+locally thick copper, resistant to 100000 insertions and removals (IEC 60664).

Temperature and humidity sensor: operates in the full temperature range of -40 ℃~85 ℃, with large-area copper plating to assist in heat dissipation.

3. Disable Scene

High frequency circuit: significant increase in signal loss (Dk fluctuation ±) above 100MHz 0.5@1GHz ）.

High temperature environment: When the continuous working temperature is greater than 105 ℃, there is a high risk of stratification (prohibited in car engine compartments).

4、 Alternative solution: Technical upgrade of multi-layer requirements

If multi-layer+flame retardant is required, the following alternative materials are recommended:

Material type, key characteristics, applicable scenarios
CEM-3 double-sided semi fiberglass board, with a cost 10% lower than FR-4, supports 4-6 layers of industrial control motherboards and LED driver boards
High Tg FR-4 Tg ≥ 170 ℃, lead-free soldering resistance, supports 12+layers of automotive electronics and server power modules
Halogen free FR-4 bromine content<900ppm, flame retardant UL94 V-0 EU environmentally friendly product (mandatory under RoHS directive)
Selection suggestion:

Low frequency boards with less than 4 layers: preferably CEM-3 (cost performance balance);

High frequency board with more than 6 layers: FR-4 mixed compression high-frequency material (such as Rogers RO4350B) must be selected