Base-Attached Encapsulant Warpage Suppression
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Solution Overview
Problem
The challenge in semiconductor encapsulation is warpage, particularly in large-area fan-out wafer level packages, where existing methods struggle to maintain package flatness and chemical resistance during the rewiring process.
Innovation Solution
A base-attached encapsulant with a specific formulation of thermosetting resin and inorganic filler, where the linear expansion coefficients of the semiconductor device, encapsulating resin, and base are carefully matched to minimize warpage, and the encapsulating resin layer contains no or minimal thermoplastic resin to enhance chemical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large area is collectively encapsulated to reduce manufacturing cost, then productivity is improved, but warpage of the package occurs after removal of the support substrate and temporary fixing material
Solution Approach 1:
The patent changes the physical and chemical parameters of the encapsulating resin by specifying a linear expansion coefficient (α2) that satisfies the inequality relationship with the semiconductor device (α1) and base (α3). This parameter optimization allows the resin to compensate for thermal expansion differences, suppressing warpage while maintaining large-area encapsulation for cost-effective manufacturing
Solution Approach 2:
The patent creates a composite structure consisting of the semiconductor device, encapsulating resin, and base, where each component's linear expansion coefficient is carefully selected to work together. The composite material approach allows the system to achieve thermal expansion compatibility, reducing warpage in large-area packages while maintaining manufacturing efficiency
2Ease of manufacture
If thermoplastic resin is added to the encapsulating resin to maintain sheet shape, then ease of manufacture is improved, but chemical resistance deteriorates
Solution Approach 1:
The patent changes the compositional parameters of the encapsulating resin by strictly limiting thermoplastic resin content to 2% by mass or less. This compositional control maintains sufficient sheet shape stability for manufacturing while preserving the chemical resistance properties of the thermosetting resin system
Solution Approach 2:
The patent applies local quality by allowing minimal thermoplastic resin (≤2%) in specific regions or amounts to provide just enough sheet shape maintenance, while the bulk of the encapsulating resin remains as chemically resistant thermosetting material. This localized approach balances manufacturing ease with chemical resistance
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
This approach effectively suppresses warpage and maintains chemical resistance, enabling the production of flat and reliable fan-out wafer level packages with reduced need for thermoplastic resin, thus improving manufacturing efficiency and package quality.
Implementation Method 1
a linear expansion coefficient α1 of the semiconductor device to be encapsulated by the base-attached encapsulant for semiconductor encapsulation, a linear expansion coefficient α2 of a cured product of the encapsulating resin layer, and a linear expansion coefficient α3 of the base satisfy both of the following formula (1) and (2)
Data Source
AI summary
A base-attached encapsulant for semiconductor encapsulation is used for collectively encapsulating a device-mounted surface of the semiconductor device-mounted substrate having semiconductor devices mounted thereon or a device-formed surface of a semiconductor device-formed wafer having semiconductor devices formed thereon. The base-attached encapsulant has a base and an encapsulating resin layer containing an uncured or semi-cured thermosetting resin component formed onto one of the surfaces of the base, and a linear expansion coefficient α1 of the semiconductor device to be encapsulated by the base-attached encapsulant, a linear expansion coefficient α2 of a cured product of the encapsulating resin layer, and a linear expansion coefficient α3 of the base satisfy both of the following formula (1) and (2);α1<α3<α2 (1)−2<α1+α2−2α3<2 (2)wherein the unit of the linear expansion coefficient is ppm/K. The base-attached encapsulant for semiconductor encapsulation which suppress package warpage even if a package with a large area is encapsulated.