FMBF Flexible Build-up Film
Ultra-Thin Solution for SAP&mSAP Multilayer PCBs
Next-Generation Flexible Build-up Material Engineered for mSAP / SAP Processes
High Flexibility × High Thermal Resistance × Low Dielectric × High Reliability
Enabling full performance upgrades for 5G, bendable, and ultra-thin circuit designs
The Evolution from Rigid to Flexible: FMBF – Making Electronics Lighter, Thinner, and More Durable
FMBF (Flexible Microcosm Build-up Film) is a high-performance, ultra-thin build-up material specifically developed for multilayer PCBs, mSAP, and SAP manufacturing processes.
It combines flexibility, high thermal resistance, low dielectric properties, and excellent reliability, making it ideal for 5G high-frequency/high-speed transmission modules, flexible substrates, and bendable packaging architectures.
With high adhesion strength and outstanding long-term environmental stability, FMBF Flexible build-up film withstands demanding fabrication processes and harsh end-use conditions—serving as a key enabling material for thinner, finer, and faster electronic products.
Common Challenges and Limitations
As electronic products advance toward higher layer counts, multifunctionality, bendability, and lightweight designs, build-up materials are expected to meet increasingly stringent demands:
- Ultra-thin substrates prone to warpage or insufficient bending durability
- 5G PCBs require extremely low-loss dielectric properties
- High-temperature processes demand superior material stability
- SAP processes require strong surface adhesion for electroplated copper
- Insufficient electrical reliability may lead to CAF or HAST failures
Conventional stacked or build-up materials often fail to simultaneously deliver flexibility, heat resistance, and low dielectric performance. FMBF was developed to overcome these challenges.
Product Advantages
| Feature | Description | Product Values |
|---|---|---|
| Flexibility & Bendability | Flexible structure; retains flexibility after build-up | Greater design freedom; ideal for FPC and foldable devices |
| Excellent Adhesion | >0.5 kg/cm（Plated Cu / FMBF） | Prevents delamination; improves yield and reliability |
| High Thermal Resistance | 288°C，5 cycles PASS | Withstands high-temperature lamination, curing, and thermal shock |
| Low Dielectric Properties | Dk = 2.44、Df = 0.0023（10 GHz） | Optimal for 5G and high-speed transmission with minimal signal loss |
| High Environmental Reliability | CAF >1000 Hr、HAST PASS | Significantly extends product service life |
| Ultra-Thin Process Compatibility | Supports 25 µm films and multilayer stacking | Ideal for thin devices and High-Density-Interconnect HDI designs |
Why Choose Us?
See the Product Comparison
| Technical Items | Microcosm FMBF Flexible Build-up Film | General Build-up Film |
|---|---|---|
| Flexibility/ Bendability | ✔ | ✘ |
| SAP/mSAP Compatibility | ✔ | ✔ |
| Adhesion Strength | High | High |
| Dielectric Performance (suitable for 5G） | Low Dk、Low Df | Low Dk、Low Df |
| Ultra-Thin Design Capability | High | Medium |
The Optimal Solution
FMBF is one of the few build-up materials on the market that simultaneously delivers flexibility, low dielectric loss, high thermal resistance, and strong adhesion, making it the ideal solution for 5G, mSAP, SAP, and ultra-thin HDI applications.
Product Application Structure
