1、 Process Technology: Innovative Breakthrough in Paper Based Double Sideization
The 22F double-sided circuit board achieves double-sided conductive layers on traditional paper substrates (cotton fiber paper+epoxy phenolic resin). The process difficulty lies in interlayer conductivity and substrate stability.
The core process is as follows:
1. Key process steps
Differences between Process Technology Points and Traditional FR-4 Double sided Panel
Preparation of 22F core board double-sided copper-clad (1oz copper foil) substrate, plasma cleaning to enhance adhesion requires low-temperature drying (80 ℃) to control paper-based water absorption and expansion
Laser drilling for via hole processing (CO ₂ laser, aperture ≥ 0.4mm)+filling with conductive adhesive instead of chemical copper deposition (paper-based is not resistant to strong acids)
Graphic transfer screen printing with corrosion-resistant ink (line width ≥ 0.25mm) → acid etching (FeCl ∝+HCl) to avoid LDI exposure and reduce costs
Low temperature lamination (150 ℃/200psi, time shortened by 30%) combined with high flowability semi cured sheet to prevent paper-based carbonization
Surface treatment is mainly based on OSP (organic solder mask), with a cost only one-third of immersion gold, and an effective period of 6 months or selective tin spraying (local heat dissipation area)
2. Technological innovation points
Flexible toughening resin: Adding polyurethane elastomer increases the flexural strength to>250MPa (close to 60% of FR-4);
Mixed pressure design: PTFE patches are embedded in high-frequency areas (such as WiFi antennas), with a cost 70% lower than full high-frequency boards;
Die punching: supports batch punching (minimum aperture 0.8mm), with an efficiency 50% higher than mechanical drilling.
2、 Core advantage: The ultimate balance between low cost and environmental protection
1. Performance comparison (scenarios below 4 layers)
Indicator 22F double-sided board FR-4 double-sided board advantages/limitations
Cost ¥ 60-100/㎡ ¥ 120-200/㎡ ↓ 40% Material cost
Environmentally friendly paper-based recycling rate>60%. Glass fiber is difficult to recycle and complies with RoHS directive
Shock absorption performance, paper-based vibration absorption characteristics, excellent rigidity, easy resonance, industrial vibration environment failure rate ↓ 30%
Maximum frequency ≤ 500MHz (PTFE patch required) ≤ 1GHz High frequency weak scalability
2. Irreplaceability advantage
Delivery speed: Urgent sample delivery within 24 hours, batch lead time of 5-6 days (20% faster than FR-4);
Convenient maintenance: through-hole inspection+jumper repair, fault location time<5 minutes;
Environmental adaptability: Passed the 85 ℃/85% RH wet heat test (industrial PLC lifespan>10 years).
3、 Application field: High cost-effective mid low frequency scenarios
1. Industrial control (accounting for 60%)
PLC communication module:
4-layer 22F board with OSP processing, capable of withstanding 100000 insertions and removals, with a cost less than 50% of FR-4;
Motor drive interface:
Partial 2oz thick copper design (current ≤ 5A), passed 1500V withstand voltage test.
2. Consumer electronics (accounting for 30%)
Smart home central control:
Double sided wiring+Bluetooth module (such as Xiaomi smart socket), mold punching process supports monthly production of 20000 square meters;
LED lighting system:
Bubble lamp driver board (aluminum based embedded heat dissipation), adopted by 70% of manufacturers worldwide.
3. Automotive Electronics (Special Adaptation)
Non safety modules: window switch, seat heating controller (requires high Tg modified resin, Tg ≥ 130 ℃);
Disable scenario: ECU/ABS and other high-frequency core systems (paper-based temperature resistance limitations).
4、 Limitations and coping strategies
Effect of defect solution
Use CEM-3 composite material instead of layer limit>4 layers to support the design of 6 layers with medium complexity
High frequency loss>500MHz area with PTFE patch (mixed pressure) insertion loss reduced to< 0.5dB@1GHz
Bake at 120 ℃ for 2 hours before welding the explosive plate online to control the moisture delamination rate to be less than 0.1%
