High dimensional stability Polyimide Stiffener (PIS) - Engineered for fine-pitch COF mechanical stability
Product Description:
High Dimensional Stability Polyimide Stiffener (PIS) is a precision-engineered reinforcement material designed for Chip-on-Film (COF) module, Fine-Pitch IC bonding, and advanced flexible IC packaging applications. It is manufactured by laminating our high-dimensional-stability PI film with a high bonding strength PSA, followed by high-precision die-cutting equipment to ensure consistent dimensions, clean edges, and excellent positional accuracy.
PIS is developed to enhance localized thickness, mechanical rigidity, and dimensional control in critical areas of flexible circuits, such as COF connect arees, Fine-Pitch IC bonding zones, and ZIF gold-finger regions. It delivers excellent insulation properties and strong bonding compatibility with Polyimide film, PET, and FR4 substrates.
PIS Stiffener also withstands localized bending and handling stress, maintaining flexibility where needed without cracking. Fully compatible with SMT assembly and solder reflow processes, they ensure high assembly yield and long-term package reliability in compact, high-density semiconductor designs.
Design Challenge in COF reinforcement:
In practical COF (Chip-on-Film) connect zone requires precise mechanical support and dimensional stability to ensure reliable electrical connections. However, several challenges arise during design and assembly:
Ultra-thin structure limitations
Stress concentration at bonding interface
Thermal shrinkage and CTE mismatch
Localized reinforcement requirement
These challenges highlight the need for advanced stiffener materials that provide precise thickness control, low thermal shrinkage, and reliable mechanical support.
Our PI Stiffener (PIS) Approach:
Our PI stiffener is specifically designed to address the mechanical and thermal challenges in COF reinforcement through a combination of material engineering and structural optimization.
Localized Structural Reinforcement
Controlled thickness & dimensional tolerance
Low CTE & Low Shrinkage Material System
High Adhesion Strength
This approach enables stable bonding performance, improved yield, and long-term reliability in advanced display applications.
Polyimide Stiffener (PIS) Structure:
Top Layer: High Dimensional Stability Polyimide film, 2mil~9mil
Middle Layer: Pressure Sensitive Adhesive (Acrylic or Silicone), 10~60µm
Bottom Layer: Transparent PET Release Liner or ETFE release film (upon request) , 50~100µm
Precision Dimensional Control & Superior Manufacturing Quality:
Dimensional tolerance: ±0.1 mm (standard), ±0.05 mm (upon request)
Burr-free and crack-free edges
No excess adhesive, air bubbles, surface scratches, foreign particles, or edge trimming defects
Consistent shape and positional accuracy for mass production
Compatible with Automated Pick-and-Place Systems for Stable Handling
High-Precision Manufacturing & Inspection for TIS
Engineered for Precision. Built for Reliability.
A complete view of PI Stiffener (PIS) production—from lamination to inspection—ensuring consistent geometry, clean edges, and dependable performance.
Available Sizes and Shapes:
PIS is available in a wide range of thicknesses, sizes, and custom shapes to meet diverse customer requirements.
COF Stiffener Design Considerations:
Design priorities focus on flatness control, thermo-mechanical reliability, and long-term bonding stability under harsh operating conditions.
- Reinforcement Objective & Target Area - Clearly define the reinforcement target area (chip, bonding, or connector zone) to ensure precise functional support.
- Stiffness & Thickness Selection - Select stiffness sufficient to control flex while avoiding excessive rigidity that may induce warpage or stress concentration.
- Flatness & Warpage Control - Ensure uniform stiffener thickness and PSA layer consistency to maintain flatness in chip and bonding areas.
- CTE & Modulus Matching - Match thermo-mechanical properties with the COF stack-up to minimize stress during temperature cycling.
- Pick-and-Place Compatibility - Stiffener geometry, surface flatness, and material rigidity must support automated pick-up and stable placement without deformation.
- Placement Accuracy & Alignment - Dimensional tolerances and adhesive tack balance must allow precise alignment and stable positioning prior to final bonding.
- Transition Zone Stress Management - Use rounded or tapered stiffener edges to reduce stress concentration at stiffness transition regions.
- Electrical Insulation & Cleanliness - Maintain high dielectric strength with low contamination and low outgassing to protect COF reliability.
- Moisture & Environmental Stability - Materials and adhesive systems must resist moisture absorption and performance degradation under humidity exposure.
Typical Applications:
Ideal for reinforcing key components in:
LCD / OLED display COF module
ZIF connector gold-finger reinforcement areas
Driver IC and advanced IC packaging structures
Flexible display panels
Flexible electronics requiring localized stiffness and dimensional control
Application Case:
I. LCD Display COF Module Reinforcement
PI Stiffener PIS enhances structural stability within COF module assemblies, enabling precise alignment, improved bonding reliability, and consistent performance in high-resolution LCD display systems.
Looking to reinforce your COF design?
Contact us to discuss application-specific PI stiffener solutions tailored to your COF structure and process conditions.
