Corner-Filled Resin for BGA Impact Resistance and Repairability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electronic component mounting structures face a trade-off between impact resistance and repairability, as filling resin in the entire gap between BGA/CSP and substrate enhances impact resistance but reduces repairability, while restricting resin to corners improves repairability at the cost of reduced bonding area and reinforcement.
Innovation Solution
An electronic component mounting structure using a resin adhesive with epoxy and flexible resins, specifically with a tensile elongation range of 5 to 40% after curing, filled in the four corners to provide impact resistance and repairability, avoiding contact with solder balls and utilizing a thixotropic ratio of 2 or more to prevent resin migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resin is filled in the entire gap between BGA/CSP and substrate, then impact resistance is improved, but repairability deteriorates
Solution Approach 1:
The patent applies local quality by concentrating the resin filling in the four corner regions of the BGA/CSP package rather than filling the entire gap. This localized approach provides sufficient impact resistance at the corners where stress concentrates during drops, while leaving the central area accessible for repair operations. The corner-specific reinforcement maintains bonding reliability without compromising repairability.
2Ease of repair
If resin is restricted to four corners of BGA/CSP, then repairability is improved, but bonding area is reduced
Solution Approach 1:
The patent applies local quality by concentrating the resin filling in the four corner regions of the BGA/CSP package rather than filling the entire gap. This localized approach provides sufficient impact resistance at the corners where stress concentrates during drops, while leaving the central area accessible for repair operations. The corner-specific reinforcement maintains bonding reliability without compromising repairability.
3Strength
If epoxy base thermosetting resin is used and cured, then bonding strength is improved, but removability deteriorates
Solution Approach 1:
The patent applies parameter changes by carefully controlling the tensile elongation parameter of the cured resin within the 5-40% range. This parameter optimization allows the resin to maintain strong bonding strength for impact resistance while simultaneously enabling removability for repair purposes. The specific elongation range creates a balance between these contradictory requirements.
Solution Approach 2:
The patent applies composite materials by combining epoxy base thermosetting resin with flexible resin components. This composite formulation achieves both high bonding strength and appropriate tensile elongation (5-40%), creating a material that provides both strong bonding and controlled removability. The composite structure allows the resin to exhibit both rigidity for strength and flexibility for elongation.
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 structure achieves high impact resistance and repairability by allowing the resin to elongate without breaking during drops, enabling easy removal and reuse of the substrate, and maintaining bonding integrity.
Implementation Method 1
the flexible resin preferably contains at least any one of a cardanol epoxidation product, polypropylene glycol diglycidyl ether, diglycidyl ether of bisphenol A-alkylene oxide adduct, DGEBA/polymeric fatty acid adduct, polymeric fatty acid polyglycidyl ester and urethane prepolymer
Implementation Method 2
the thixotropic ratio of the resin is preferred to be 2 or more
Implementation Method 3
the resin preferably further includes a rubber, the rubber including at least any one of natural rubber, styrene rubber, butadiene rubber, chloroprene rubber, butyl rubber, nitrile rubber, ethylene propylene rubber, silicone rubber and urethane rubber
Data Source
AI summary
The invention intends to provide an electronic component mounting structure where the repairability and the impact resistance are combined. In an electronic component mounting structure, a plurality of solder balls disposed in plane between an electronic component and a substrate is melted to bond the electronic component and the substrate and a resin of which tensile elongation after the curing is in the range of 5 to 40% is filled in portions that are gaps between the electronic component and the substrate and correspond to at least four corners of the electronic component to reinforce. Since the reinforcement area is small, the repairability such as the easy removability of the resin and the reusability of the substrate are excellent, the resin itself is allowed to expand to the impact at the drop to play a role of reinforcing the bonding without breaking, and the impact resistance is excellent as well.