熱硬化型層間絶縁フィルム
  • 熱硬化型層間絶縁フィルム
  • 熱硬化型層間絶縁フィルム（使用箇所）

Thermosetting Interlayer Insulating Film

Build-up film that contributes to finer wiring and high-speed communication in electronic devices.

An insulating material that achieves both low transmission loss and warpage control in multi-layered, large-sized IC package substrates. It ensures stable performance even in advanced substrates featuring finer wiring and thinner profiles. It contributes to greater design freedom and the manufacturing of highly reliable FC-BGA substrates.
  • Electronics

What is Build-up Film?

Build-up Film

Build-up film is an interlayer dielectric material used to form fine wiring layers in advanced IC package substrates. As the performance of electronic devices improves, IC package substrates are also becoming denser to support higher speeds and improved performance. In addition to fine via formation capability and low dielectric properties, dimensional stability that suppresses warpage during processing and mounting has become increasingly important. These advanced IC package substrates are widely adopted in fields such as AI, servers, and network equipment. Build-up films have become essential materials that enable high-performance and high-reliability electronic devices.

Features

Build-up Film

Sekisui Chemical’s build-up film combines excellent transmission characteristics and dimensional stability, with a proven track record in high-layer-count, large-size high-end IC package substrates (FC-BGA).
Its low dielectric and low-warping properties enhance design flexibility and contribute to the realization of next-generation devices with higher performance and reliability.

  • Warpage
    control
  • Low transmission loss
  • FLS (Fine
    Line Space) compatibility
  • Excellent embeddability

Sekisui’s Strengths

Sekisui Chemical’s build-up film achieves low dielectric loss (low Df), consistent surface roughness after desmear, and excellent crack resistance through proprietary compounding and coating technologies. These features contribute to low transmission loss, fine pattern compatibility, and improved yield required for next-generation package substrates.

Fine-pattern compatibility

Fine-pattern compatibility
High-Resolution Resist Pattern

BUF: QX / SEKISUI CHEMICAL Co., Ltd.
DFR: DA Series / Asahi Kasei Corp.
Exposure: DI Exposure / ADTEC Engineering Co., Ltd.

High embeddability & void suppression

High embeddability & void suppression
High embeddability & void suppression
X-Z Profile After Lamination

Low-stress design for delamination & warpage control

Low-stress design for delamination & warpage control
Pad Wall Cross-section
Low-stress design for delamination & warpage control
Stress Simulation After Reflow

In addition, leveraging many years of tape manufacturing expertise, Sekisui can flexibly support various thickness requirements.
Standard products are available in 20–100 µm thickness (2.5 µm increments), and other thicknesses are available upon request.

Build-up film

Examples of SEKISUI Build-up Film Customers
(FC-BGA Manufacturers)

TOPPAN Inc. Nan Ya PCB Corporation

Current Product Lineup

For FCBGA For Embedded
NX04H NQ07XP QX03 EL TC HE
HVM Sampling Development Development
Df @5.8GHz 0.0090 0.0037 0.0023 ≦0.0025 0.0084 0.0050
Dk @5.8GHz 3.3 3.3 3.3 ≦2.5 3.4 5
CTE (25-150℃) ppm/℃ 24.5 27 17 17-23 13 20
Tg (DMA) ℃ 205 183 183 > 170 206 170
Young’s Modulus GPa 8 10.4 13.1 > 7 12.3 20
Elongation % 2.4 2.6 2.9 > 1.5 1.2 1.2
Tensile Strength MPa 100 105 110 > 70 102 90
Thermal Conductivity W/m K 0.5 0.5 0.6 > 0.3 0.6 2.0

Applications

Sekisui Chemical’s build-up film is used in IC package substrates that perform advanced communication and computation processes, and is widely applied in the following fields.

Applications
AI Processing Modules AI Processing Modules
Offers thermal stability and process adaptability to meet the high heat generation and high-density wiring demands of GPUs and AI chips.
Data Center Servers Data Center Servers
With excellent dielectric properties and durability, it contributes to the reliability of high-end server circuits that support large-scale data processing.
Ethernet Switches Ethernet Switches
Extensively adopted worldwide in high-speed network equipment that supports the 5G and cloud computing era.
High-performance PCs & Workstations High-performance PCs & Workstations
Balances signal integrity and manufacturing efficiency in increasingly complex, multilayered systems.

Process Flow

SEKISUI’s Build-up Dielectric Films are the ONLY alternative mass producing dielectric build-up material used in manufacturing of FC-BGA substrates with full compatibility with current Semi-Additive Process (SAP) manufacturing lines.
Several major substrate suppliers in Japan and Taiwan are manufacturing advanced FC-BGA substrates incorporating SEKISUI’s Build-up Dielectric Films and major OSATs have experience assembling those substrates.

Semi-Additive Process (SAP)

Semi-Additive Process (SAP)Semi-Additive Process (SAP)

Please contact us if you need detailed SAP manufacturing conditions when using SEKISUI Build-up Dielectric Film

Contact Us

SEKISUI is continuously working with IC design houses, semiconductor manufacturers, and substrate suppliers to develop new build-up dielectric films to enable next generation challenges facing advanced substrates such as lowering Df to meet the needs of 224Gb Ethernet Switch Products and beyond.
Please contact us for any development needs.

  • Looking to enhance the reliability of high-end server circuits
  • Interested in developing a new build-up film etc.
Get in Touch

Document download

  • All
  • Electronics
Name Type File Update File
Catalog 〈Electronics〉：Thermosetting Interlayer Insulating Film Electronics pdf 2025-09-30 Download2.83 MB
Ask an Expert