Warp Compensation Sheet for Electronic Panel Encapsulation
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Solution Overview
Problem
Warping during encapsulation of electronic devices in planar panel configurations complicates the process of adding interconnects, affecting manufacturing yields and costs, especially when multiple devices are involved and primary faces need to be exposed for electrical connections.
Innovation Solution
The use of a warp compensation sheet (WCS) with a specific coefficient of thermal expansion (CTE) that reverses the direction of warping from concave to convex, allowing for proper sealing and processing of the panel, which includes mounting the devices in openings of the WCS with a temporary adhesive, applying encapsulation, and ensuring the CTE of the WCS is lower than that of the encapsulant to achieve a convex warp less than 5% of the panel's lateral dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encapsulation is performed on multiple electronic devices in planar panel configuration, then environmental protection and facilitation of external connections are achieved, but warping occurs during encapsulation that complicates adding interconnects
Solution Approach 1:
The patent applies preliminary action by pre-mounting the electronic devices onto a carrier substrate in the desired planar panel configuration before encapsulation. This preliminary arrangement ensures proper positioning and alignment, allowing subsequent encapsulation to be performed without causing warping that would complicate interconnect addition. The devices are prepared and positioned in advance, so the encapsulation process proceeds smoothly while maintaining manufacturability.
Solution Approach 2:
The patent introduces an intermediary carrier substrate that mediates between the electronic devices and the encapsulation material. This carrier substrate provides a stable base for mounting multiple devices in planar configuration and serves as an interface during encapsulation, preventing warping issues. The carrier acts as a buffer that maintains structural integrity throughout the encapsulation process, enabling easy addition of interconnects afterward.
2Productivity
If planar processing technology is used to interconnect devices in the panel, then manufacturing efficiency is improved, but warping during encapsulation makes the process difficult
Solution Approach 1:
The patent applies preliminary action by pre-establishing a flat, stable carrier substrate structure before encapsulation. This preliminary preparation ensures that the panel maintains its flatness throughout the encapsulation process, preserving the precision required for subsequent planar processing operations. By preparing the substrate and device arrangement in advance with proper support structures, the patent prevents warping that would otherwise compromise manufacturing precision.
Solution Approach 2:
The patent applies parameter changes by modifying the thermal and mechanical parameters of the encapsulation process to prevent warping. This includes controlling curing temperatures, using appropriate encapsulation material properties, and adjusting processing parameters to maintain panel flatness. By carefully managing these parameters, the patent ensures that encapsulation does not induce warping, thereby maintaining the precision needed for planar processing while preserving manufacturing efficiency.
3Ease of operation
If devices are encapsulated in planar panel configuration with exposed primary faces, then accessibility for electrical connections is improved, but warping control becomes critical to achieving high yields
Solution Approach 1:
The patent applies preliminary action by pre-arranging devices on a stable carrier substrate with their primary faces exposed and properly oriented before encapsulation. This preliminary configuration ensures that electrical connection accessibility is maintained while preventing warping issues. The devices are positioned and secured in advance on the carrier, which provides structural support during encapsulation, thereby maintaining both accessibility and manufacturing yield.
Solution Approach 2:
The patent introduces an intermediary carrier substrate that mediates between the exposed primary faces of the devices and the encapsulation material. This carrier maintains the structural integrity and flatness of the panel during encapsulation, preventing warping that would compromise manufacturing yield. Simultaneously, the carrier allows the primary faces to remain accessible for electrical connections, achieving both accessibility and high yield through this intermediary structure.
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 ensures that the electronic panel assemblies can be processed using conventional planar technology, maintaining flatness and facilitating the formation of integrated electronic assemblies with reduced manufacturing complexity and costs.
Implementation Method 1
The use of a warp compensation sheet (WCS) with a specific coefficient of thermal expansion (CTE) that reverses the direction of warping from concave to convex
Data Source
AI summary
Methods and apparatus are provided for an electronic panel assembly (EPA) (82, 83), comprising: providing one or more electronic devices (30) with primary faces (31) having electrical contacts (36), opposed rear faces (33) and edges (32) therebetween. The devices (30) are mounted primary faces (31) down on a temporary support (60) in openings (44) in a warp control sheet (WCS) (40) attached to the support (60). Plastic encapsulation (50) is formed at least between lateral edges (32, 43) of the devices (30) and WCS openings (44). Undesirable panel warping (76) during encapsulation is mitigated by choosing the WCS coefficient of thermal expansion (CTE) to be less than the encapsulation CTE. After encapsulation cure, the EPA (82) containing the devices (30) and the WCS (40) is separated from the temporary support (60) and, optionally, mounted on another carrier (70) with electrical contacts (36) exposed. Thin film insulators (85) and conductors (87) are desirably applied to couple electrical contacts (36) on various devices (30) to each other and to external terminals (88), thereby forming an integrated multi-device EPA (84).