Anisotropic Conductive Connection Structure with Protruding Electrode
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Solution Overview
Problem
Existing flip chip bonding methods, such as ultrasonic and eutectic methods, face issues like connection failure, short circuits, high costs due to material expenses, and process complexity, while anisotropic conductive connections using films have limitations in reducing protruding portions effectively, which can lead to increased connection resistance and reliability concerns.
Innovation Solution
An anisotropic conductive connection structure with a protruding portion on the first electrode terminal, an anisotropic conductive adhesive layer containing electrically conductive particles, and specific geometric ratios to optimize particle trapping and compression, ensuring reduced connection resistance and enhanced reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protruding portion is made as small as possible to avoid connection failure, then connection reliability is improved, but electrically conductive particles cannot be compressed sufficiently leading to increased connection resistance
Solution Approach 1:
The protruding portion is designed with a specific height ratio (less than 60% of particle diameter) to create a localized compression zone. This allows the protruding portion to effectively trap and compress electrically conductive particles without requiring the entire structure to be minimized, thus maintaining both reliability and acceptable connection resistance
Solution Approach 2:
The invention changes the critical parameter from minimizing protruding portion size to controlling the height ratio between protruding portion and particle diameter. This parameter optimization enables sufficient particle compression while preventing connection failure, resolving the contradiction between reliability and connection resistance
2Strength
If ultrasonic connection method is used to connect electrode terminals, then connection strength is improved, but electrode terminals are largely oscillated causing connection failure and short circuits
Solution Approach 1:
The invention extracts and eliminates the ultrasonic oscillation step from the connection process. By using an anisotropic conductive film with thermally conductive particles that bond through heat and pressure alone, the harmful oscillations are removed while maintaining connection strength through alternative bonding mechanisms
Solution Approach 2:
The ultrasonic mechanical vibration system is replaced with a thermal-field-based bonding system. The anisotropic conductive film utilizes heat and pressure to activate bonding between electrode terminals, substituting the mechanical oscillation mechanism with a thermal processing approach that avoids connection failure
3Strength
If eutectic method is used with high heating temperature to connect electrode terminals, then connection strength is improved, but flexible board deforms causing position shift and connection failure
Solution Approach 1:
The invention changes the heating temperature parameter from high temperature (400°C in eutectic method) to a lower temperature range suitable for flexible boards. The anisotropic conductive film is designed to bond at these reduced temperatures, preventing board deformation while achieving strong connections
Solution Approach 2:
The anisotropic conductive film acts as a consumable bonding medium that enables connection at lower temperatures. This disposable film layer facilitates bonding without requiring the electrode terminals or flexible board to withstand high temperatures, thus preventing deformation
4Device complexity
If anisotropic conductive film method is used to connect electrode terminals, then process complexity is reduced, but protruding portion cannot be effectively reduced leading to increased connection resistance
Solution Approach 1:
The invention introduces local quality control through the protruding portion design with specific height ratio. This localized structural feature enables effective particle compression in the bonding interface without requiring complex processing steps, thus maintaining process simplicity while reducing connection 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
The proposed structure effectively reduces connection resistance and enhances reliability by trapping and compressing electrically conductive particles within the protruding portion, ensuring strong adhesion between electrode terminals and improved durability through specific geometric and material optimizations.
Implementation Method 1
electrically conductive particles that provide conduction between the first electrode terminal and the second electrode terminal
Data Source
AI summary
An anisotropic conductive connection structure body includes: a first electrode terminal on a surface of which a protruding portion is formed; a second electrode terminal; and an anisotropic conductive adhesive layer containing electrically conductive particles that provide conduction between the first electrode terminal and the second electrode terminal. A ratio of a height of the protruding portion to a before-compression particle size of the electrically conductive particle is less than 60%, an opening area ratio of the first electrode terminal is more than or equal to 55%, and a height of the second electrode terminal is more than or equal to 6 μm.