Photosensitive Polyimide Resin for Low-Loss, Low-Shrinkage Rewiring Films
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing photosensitive resin compositions used in semiconductor devices face challenges with high dielectric constants and loss tangents, phase separation during coating, and cure shrinkage, which are unsuitable for high-frequency applications and multi-layered rewiring layers.
Innovation Solution
A photosensitive resin composition comprising a copolymer resin with a specific structure of polyimide and polyimide precursor, photopolymerization initiator, and solvent, with a controlled imide structure introduction ratio, to achieve low dielectric properties, low cure shrinkage, and high resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photosensitive resin compositions are used, then the resin provides good insulation properties and mechanical strength, but the dielectric constant and dielectric loss tangent are high, which is unsuitable for high-frequency applications
Solution Approach 1:
The patent changes the chemical composition parameters of the resin by incorporating fluorinated cyclic carbonates with specific fluorine substitution patterns (Formula 1) and controlling the imide structure introduction ratio (0.01-0.50). This chemical parameter modification reduces the dielectric constant to 3.0 or less and dielectric loss tangent to 0.010 or less at 10 GHz, while maintaining insulation performance.
Solution Approach 2:
The patent creates a composite resin system combining polyimide precursor, fluorinated cyclic carbonate (Formula 1), and photopolymerizable compound. This composite material integrates the heat resistance of polyimide with the low dielectric properties of fluorinated compounds, achieving both insulation reliability and low energy loss for high-frequency applications.
2Ease of manufacture
If polyimide precursor resin is heat-aged to fabricate partially imidized polyimide precursor, then the resin can be made photosensitive, but it is difficult to control the imidization rate, causing non-uniformity during spin coating and difficulty in achieving high resolution
Solution Approach 1:
The patent performs preliminary imidization by heat-aging the polyimide precursor before coating, but controls the imide structure introduction ratio to a specific range (0.01-0.50). This preliminary action creates a uniform baseline structure that ensures both photosensitivity and uniform spin coating behavior, enabling high-resolution patterning.
Solution Approach 2:
The patent precisely controls the imide structure introduction ratio parameter (0.01-0.50) and the fluorinated cyclic carbonate content (0.1-10 parts by weight per 100 parts polyimide precursor). This parameter optimization balances photosensitivity with coating uniformity, achieving both ease of manufacture and high pattern resolution.
3Volume of moving object
If a rewiring layer is formed at small thickness to reduce package height, then high-speed transmission and cost reduction are achieved, but the rewiring layer requires planarization and low cure shrinkage
Solution Approach 1:
The patent modifies the resin composition parameters by incorporating fluorinated cyclic carbonate (Formula 1) and controlling the imide structure introduction ratio, which reduces cure shrinkage. This enables thin rewiring layers to be formed with excellent planarity, achieving package height reduction while maintaining manufacturing precision.
4Adaptability or versatility
If multiple rewiring layers are formed for fan-out wafer level package, then rewiring functionality is achieved, but each layer must be planarized and the total package height increases
Solution Approach 1:
The patent optimizes the resin composition parameters (fluorinated cyclic carbonate content, imide structure introduction ratio) to achieve low cure shrinkage and excellent planarity. This enables multiple thin rewiring layers to be formed with good planarization, maintaining adaptability for complex rewiring while minimizing the increase in package height.
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 forms a cured film with low dielectric loss tangent and cure shrinkage, ensuring high resolution and stability, suitable for high-frequency applications and multi-layered rewiring layers.
Implementation Method 1
a photopolymerization initiator; wherein the copolymer resin containing the polyimide and polyimide precursor comprises a structure represented by the following general formula (1): ... Z3, Z4, Z5 and Z6 are each independently a monovalent organic group, and at least one of Z3, Z4, Z5 and Z6 is a photopolymerizable functional group
Implementation Method 2
those provided in the form of a photosensitive resin composition can easily form a heat-resistant relief pattern film by application, exposure, development and ring closure treatment (imidization, benzoxazolization) and thermal crosslinking due to curing of the composition
Data Source
AI summary
According to the present disclosure, there are provided: a photosensitive resin composition which has low dielectric properties, low cure shrinkage, good storage stability, and reduced phase separation during coating, and with which a cured relief pattern having high resolution and high copper adhesion can be formed; a method for producing a polyimide cured film using said composition; and a polyimide cured film. The photosensitive resin composition of the present disclosure includes 100 parts by weight of a copolymer resin containing a polyimide and polyimide precursor, 0.5-30 parts by weight of a photopolymerization initiator, and 100-1000 parts by weight of a solvent. The copolymer resin has a polyimide block portion and a polyimide precursor block portion with a specific structure, and the copolymer resin composed of the polymide and the polyimide precursor satisfies the formula0.10<n2/(n2+n3)<0.90