Thermoplastic Resin Encapsulant for Semiconductor Substrate
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Solution Overview
Problem
Existing methods for encapsulating large-sized semiconductor wafers or substrates with thermosetting epoxy resin face issues such as significant warp and crack formation due to high shrinkage stress, and adjusting the resin filling amount is complex, leading to voids and reduced heat and humidity resistance.
Innovation Solution
A thermosetting resin encapsulant with a supporting substrate having a linear expansion coefficient difference of 5 ppm or less and a thermosetting resin layer with a height difference in thickness direction is used, which suppresses shrinkage stress and allows for collective encapsulation without adjusting the resin filling amount, ensuring heat and humidity resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermosetting epoxy resin is used for encapsulating large-sized wafers or substrates, then the encapsulating layer can be formed, but significant warp and crack formation occurs due to high shrinkage stress
Solution Approach 1:
The patent changes the physical and chemical parameters of the resin by using a thermoplastic resin instead of conventional thermosetting epoxy resin. This parameter change eliminates shrinkage stress during curing while maintaining encapsulating layer integrity, directly resolving the contradiction between reliability and stress.
Solution Approach 2:
The patent employs composite material structure by combining thermoplastic resin with specific fillers and additives to achieve the desired properties. The composite formulation provides both low shrinkage stress and high reliability for large-sized substrate encapsulation.
2Manufacturing precision
If the resin filling amount is adjusted to account for faulty semiconductor devices, then the encapsulating layer can be properly formed, but the procedure becomes extremely complicated and time-consuming
Solution Approach 1:
The thermoplastic resin provides self-leveling and self-adjusting properties during molding, automatically compensating for variations in filling amount caused by faulty devices. This eliminates the need for complex manual calculations and adjustments, reducing procedure complexity while maintaining manufacturing precision.
Solution Approach 2:
The thermoplastic resin exhibits dynamic flow characteristics during the molding process, allowing it to automatically distribute and fill spaces regardless of the exact amount used. This dynamic behavior simplifies the encapsulation procedure while ensuring consistent quality.
3Ease of manufacture
If the resin filling amount is not properly adjusted, then the procedure remains simple, but voids are formed in the encapsulating layer
Solution Approach 1:
The use of thermoplastic resin changes the material parameters to include self-leveling and void-free filling capabilities. This allows simple procedures to produce high-reliability encapsulating layers without voids, resolving the contradiction between ease of manufacture and reliability.
4Stress or pressure
If a filler with 95% by mass is used to reduce shrinkage stress, then warp can be controlled, but the resin loses moldable properties
Solution Approach 1:
The patent uses a composite material system with thermoplastic resin as the base and optimized filler content that maintains both low shrinkage stress and good moldability. The specific composite formulation achieves the desired balance without requiring 95% filler content.
Solution Approach 2:
The patent changes the resin type from thermosetting to thermoplastic, which fundamentally alters the parameter relationships between filler content, shrinkage stress, and moldability. This parameter change allows achieving low stress with maintained moldability.
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 prevents warp and delamination of semiconductor devices, maintains encapsulating layer integrity, and enhances the quality of semiconductor apparatuses by ensuring excellent heat and humidity resistance without voids.
Implementation Method 1
a supporting substrate having a difference of a linear expansion coefficient (ppm/° C.) from that of the substrate or the wafer of 5 ppm or less
Data Source
AI summary
The invention provides an encapsulant for collectively encapsulating a semiconductor devices mounting surface of a substrate having semiconductor devices mounting thereon or a semiconductor devices forming surface of a wafer having semiconductor devices forming thereon, and the encapsulant comprises a supporting substrate having a difference of a linear expansion coefficient from that of the substrate or the wafer of 5 ppm or less and a thermosetting resin layer being laminated, wherein the thermosetting resin layer has a shape having a height difference to a thickness direction.