BT PCB | High-Tg Low-Loss IC Substrate | Memory & RF Chip Packaging | DuxPCB
Overview of BT PCB
BT PCB (Bismaleimide-Triazine) represents the pinnacle of substrate technology for IC packaging and high-frequency applications. Formulated from a unique blend of bismaleimide and triazine resins, these boards offer a superior glass transition temperature (Tg) and exceptional thermal stability compared to standard FR-4 materials. DuxPCB utilizes premium BT laminates from Mitsubishi Gas Chemical (MGC) and Isola to deliver ultra-stable, high-density interconnect (HDI) solutions. Our BT PCBs are engineered for the rigorous demands of chip-scale packaging (CSP), memory modules, and high-performance RF components where signal integrity and dimensional stability are non-negotiable.
Thermal Stability & Dimensional Integrity for IC Substrates
The primary advantage of BT resin is its incredibly low Coefficient of Thermal Expansion (CTE), particularly in the Z-axis. This ensures that microvias and fine-pitch solder joints remains intact during high-temperature reflow and extreme thermal cycling. Unlike build-up materials that may warp under stress, BT substrates provide a rigid, reliable core that prevents delamination and via cracking in complex 2.5D and 3D packaging environments. This makes DuxPCB’s BT solutions the industry standard for memory chips and power-sensitive mobile electronics.
Advanced Signal Integrity for RF & High-Speed Modules
With a stable Dielectric Constant (Dk) and a low Dissipation Factor (Df), BT PCBs minimize signal attenuation at frequencies exceeding 6 GHz. This electrical performance is critical for 5G transceivers, MEMS sensors, and baseband units. DuxPCB’s manufacturing process maintains strict impedance control within ±10%, utilizing advanced laser drilling to achieve microvias as small as 0.075mm. By combining BT’s low-loss properties with our Class 3 manufacturing standards, we provide the precision required for next-generation telecommunications and aerospace avionics.
Technical Capability Table
| Property | Technical Specification |
|---|
| Z-axis CTE below Tg | 55 ppm/℃ |
| Z-axis CTE above Tg | 275 ppm/℃ |
| Relative permittivity (Real Dk) | 3.70 @ 1 GHz |
| Loss tangent (Df) | 0.015 |
| Glass transition temperature (Tg) | 180 ℃ |
| Decomposition temperature (Td) | 325 ℃ |
| Thermal conductivity | 0.35 W/m·K |
| Feature | Capabilities |
|---|
| Layer Count | 1-40L |
| PCB Thickness | 0.2-8mm |
| Thickness Tolerance | ≤1.0mm: +/-0.10mm, >1.0mm:+/-10% |
| Minimum PCB Size | 2.5x2.5mm (panel), 10x10mm (single) |
| Maximum PCB Size | 500x1200mm |
| Maximum Copper | 18oz |
| Materials | MGS, Rogers, Isola, etc. |
| Min Tracing/Spacing | 3mil/3mil |
| Surface Finish | plating NI/AU, plating hard Gold, ENIG, Immersion Tin, Immersion silver, OSP, ENIG+OSP |
| Impedance Control | ±10% |
| Applications | Memory chip, RF chip, MEMS chip |
| Drilling | Mechanical: 0.15mm (6mil) | Laser: 0.075mm (3mil) |
| Min Annular Ring | 4mil |
| Lead time | 4-7 business days |
| Certification | UL, RoHS, ISO 9001, ISO 13485, IATF 16949 |
| IPC Standard | IPC 6012 Class 3 |
| Feature | BT PCB | ABF PCB |
|---|
| Material Composition | Bismaleimide-Triazine (BT) resin | Ajinomoto Build-up Film (ABF) |
| Thermal Properties | High Tg, superior heat resistance | Moderate Tg |
| Electrical Properties | Low Dk and low Df | Low Dk |
| Moisture Resistance | Excellent | Good |
| Mechanical Strength | High core stability and rigidity | Flexible build-up layers |
| Layer structure | Used for core layers and IC substrates | Build-up layers for high pin counts |
| Application Areas | Mobile phones, memory, RF modules | CPUs, GPUs, high-end computing |
| Cost | Expensive (Premium Material) | Cost-effective for mass consumer CPUs |
Why Partner with DuxPCB?
- 1. Eliminating Design-to-Reality Gaps: Many vendors reject complex BT designs due to drilling difficulties and resin hardness. DuxPCB excels where others fail, successfully manufacturing high-layer count BT boards that meet strict aerospace and medical tolerances.
- 2. Guaranteed Impedance Stability: Signal drift in RF modules often leads to costly field failures. We utilize TDR testing and precision etching to ensure your high-speed signals remain within spec, even in the most compact layouts.
- 3. Zero-Delamination Mastery: Using specialized press cycles for exotic materials like MGS and Isola, we eliminate the risk of delamination during multi-stage reflow, a common failure point in high-Tg substrates from low-cost shops.
- 4. Pre-Production Error Detection: Our DFM engineering team reviews every trace and via before fabrication, catching latent errors in fine-pitch BGA and microvia patterns that would otherwise result in scrap.
Engineering FAQs
Q1: Why is BT resin preferred for memory module packaging?
A: BT resin provides a very low CTE and high moisture resistance, ensuring the substrate remains dimensionally stable during the high-heat cycles of die bonding and encapsulation, which is critical for the longevity of DRAM and Flash chips.
Q2: What is the main manufacturing challenge with BT PCB?
A: The material is significantly harder and more brittle than FR-4, making laser and mechanical drilling more difficult. DuxPCB uses specialized drill bits and optimized feed rates to ensure clean, burr-free holes and reliable plating.
Q3: Can BT be used in a hybrid stackup with other materials?
A: Yes, BT can be combined with other high-performance materials like Rogers for specific RF requirements, provided the thermal expansion rates are carefully managed during the lamination process.
Q4: How does DuxPCB ensure quality for IATF 16949 compliance?
A: Every BT batch undergoes rigorous cross-section analysis, AOI, and electrical testing to ensure compliance with automotive safety and reliability standards.
To receive a technical review of your design or a rapid quote, please upload your Gerber files to our secure portal or contact our engineering team directly for material selection assistance.
