Photo-curable Resin Composition for Low CTE Dry Film Solder Resist
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Solution Overview
Problem
Current dry film solder resists face challenges in achieving a low coefficient of thermal expansion and high mechanical properties, which are essential for forming fine patterns and preventing warpage in semiconductor package substrates, while also requiring excellent heat resistance and insulating properties.
Innovation Solution
A photo-curable and heat-curable resin composition is developed, incorporating an acid-modified oligomer, a photopolymerizable monomer, a heat-curable binder, and a plate-like inorganic filler with specific properties, such as talc powder, to create a dry film solder resist with a low coefficient of thermal expansion and high Young's modulus, enabling the formation of fine patterns and improved mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the content of filler is increased to lower the coefficient of thermal expansion, then the coefficient of thermal expansion is reduced, but poor coating phenomenon occurs due to filler cohesion and elongation percentage ratio is reduced
Solution Approach 1:
The patent changes the particle size parameters of the filler from conventional ranges to specific ranges (D50: 0.5-2.0 μm, top size: 3-10 μm) and adjusts the filler content parameter to 20-60 wt% based on solid content. These parameter optimizations enable achieving low CTE (less than 20 ppm/K) while preventing filler cohesion and maintaining good coating properties.
Solution Approach 2:
The patent creates a composite resin composition combining multiple components: acid-modified oligomer (5-75 wt%), photopolymerizable monomer (5-30 wt%), heat-curable binder (0.5-10 wt%), and plate-like inorganic filler (20-60 wt%). This composite formulation achieves synergistic effects where the specific combination and ratios of components enable low CTE, high Young's modulus (9-11 GPa), and good coating properties simultaneously.
2Strength
If the content of filler is increased to increase Young's modulus, then the Young's modulus is increased, but the formation of fine patterns becomes unfavorable
Solution Approach 1:
The patent optimizes the filler particle size parameters (D50: 0.5-2.0 μm, top size: 3-10 μm) to achieve a balance between mechanical strength and pattern formation capability. The plate-like shape with specific size range provides high Young's modulus (9-11 GPa) while the controlled size distribution prevents interference with fine pattern formation during photolithography processes.
Solution Approach 2:
The patent uses plate-like inorganic filler with anisotropic shape characteristics. The plate-like structure provides localized reinforcement in specific directions, achieving high Young's modulus where needed while maintaining overall film flexibility and pattern formation capability in other aspects.
3Weight of stationary object
If the thickness of the substrate is reduced, then the device becomes more lightweight and miniaturized, but dimensional instability and warpage phenomena become more serious
Solution Approach 1:
The patent develops a resin composition with specifically optimized parameters: low CTE (less than 20 ppm/K) matching modern thin substrates, high Young's modulus (9-11 GPa) for dimensional stability, and controlled glass transition temperature. These parameter optimizations enable the resin to maintain dimensional stability in thin substrates, preventing warpage and positioning issues during thermal processing.
Solution Approach 2:
The patent specifically addresses thermal expansion mismatch by formulating a resin composition with CTE less than 20 ppm/K, which closely matches the CTE of modern thin substrates and core materials (10 ppm or less). This thermal expansion matching prevents dimensional instability and warpage in miniaturized devices with reduced substrate thickness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition effectively reduces the coefficient of thermal expansion to less than 20 ppm/K and increases the Young's modulus to 9-11 GPa, enhancing the solder resist's ability to form fine patterns and withstand thermal stress, thus addressing the limitations of existing technologies.
Implementation Method 1
a photo-curable and heat-curable resin composition including a photopolymerizable monomer having at least two photo-curable unsaturated functional groups
Implementation Method 2
a heat-curable binder having a heat-curable functional group
Data Source
AI summary
The present invention relates to a photo-curable and heat-curable resin composition including: an acid-modified oligomer having a photo-curable functional group having an acrylate group or an unsaturated double bond, and a carboxyl group in the molecule; a photopolymerizable monomer having at least two photo-curable unsaturated functional groups; a heat-curable binder having a heat-curable functional group; a plate-like inorganic filler having an E-modulus of 90 to 120 (Gpa); a dispersant; and a photo-initiator, and a dry film solder resist prepared therefrom.