Encapsulant Base Layer for Semiconductor Warp Prevention
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Solution Overview
Problem
Existing semiconductor encapsulation methods for large-diameter substrates and wafers face issues with warping and peeling due to shrinkage stress of epoxy resins, leading to poor appearance and laser marking properties in semiconductor apparatuses.
Innovation Solution
An encapsulant with a base is developed, featuring a surface resin layer formed from curable materials like epoxy resins, silicone resins, or hybrid resins on one side and an uncured or semi-cured thermosetting resin layer on the other, which suppresses warp and peeling, while allowing for good appearance and laser marking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid epoxy resin or epoxy molding compound is molded under pressure and heated condition to encapsulate the device mounting surface, then encapsulation is achieved, but shrinkage stress causes the substrate or wafer to warp and semiconductor devices to peel away
Solution Approach 1:
The encapsulation system is divided into multiple functional layers: a release layer on the substrate, an encapsulant layer containing the semiconductor devices, and a cover layer. This segmentation allows each layer to perform its specific function independently, with the release layer managing adhesion and the encapsulant layer providing protection, thereby reducing stress concentration and preventing warping
Solution Approach 2:
A release layer is introduced as an intermediary between the substrate and the encapsulant layer. This release layer has controlled adhesive properties that allow it to bond to both the substrate and the encapsulant, acting as a stress buffer that prevents direct transmission of shrinkage stress from the encapsulant to the substrate, thereby preventing warping and device peeling
2Reliability
If a liquid epoxy resin or epoxy molding compound is molded under pressure and heated condition, then encapsulation is achieved, but shrinkage stress causes semiconductor devices to peel away from the substrate
Solution Approach 1:
The encapsulation system is divided into multiple functional layers: a release layer on the substrate, an encapsulant layer containing the semiconductor devices, and a cover layer. This segmentation allows each layer to perform its specific function independently, with the release layer managing adhesion and the encapsulant layer providing protection, thereby reducing stress concentration and preventing warping
Solution Approach 2:
A release layer is introduced as an intermediary between the substrate and the encapsulant layer. This release layer has controlled adhesive properties that allow it to bond to both the substrate and the encapsulant, acting as a stress buffer that prevents direct transmission of shrinkage stress from the encapsulant to the substrate, thereby preventing warping and device peeling
3Shape
If an encapsulant with a base is used to suppress shrinkage stress, then warping and peeling are prevented, but the surface appearance and laser marking properties deteriorate
Solution Approach 1:
Different regions of the encapsulation structure are assigned different properties: the encapsulant layer has low shrinkage stress characteristics for structural stability, while the cover layer has high optical quality for surface appearance. This local differentiation allows the bulk encapsulation to prevent warping while the surface layer provides good appearance and laser marking properties
Solution Approach 2:
The encapsulation system uses a composite structure with a base encapsulant layer and a separate cover layer. The cover layer is made of material optimized for surface quality and optical properties, while the base encapsulant provides mechanical support and stress control. This composite approach combines the advantages of both material types to achieve both structural stability and surface quality
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 encapsulant effectively prevents warp and peeling of semiconductor devices, enabling the production of semiconductor apparatuses with improved appearance and laser marking properties.
Implementation Method 1
shrinkage stress of the epoxy resin, etc., at the time of encapsulating and curing
Implementation Method 2
a curable resin layer composed of an uncured or semi-cured thermosetting resin
Implementation Method 3
cured by UV irradiation or heating
Data Source
AI summary
The present invention provides an encapsulant with a base for use in semiconductor encapsulation, for collectively encapsulating a device mounting surface of a substrate on which semiconductor devices are mounted, or a device forming surface of a wafer on which semiconductor devices are formed, the encapsulant comprising the base, an encapsulating resin layer composed of an uncured or semi-cured thermosetting resin formed on one surface of the base, and a surface resin layer formed on the other surface of the base. The encapsulant enables a semiconductor apparatus having a good appearance and laser marking property to be manufactured.