Polymer Bump Structure with Grooves for Enhanced Coupling
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Solution Overview
Problem
Conventional gold bump structures on silicone substrates have insufficient contact area and are prone to displacement issues during bonding, leading to reduced coupling strength and potential short circuits, while also being costly due to the use of gold.
Innovation Solution
A bump structure comprising polymer blocks, grooves, an under bump metallurgy layer, and a connection metal layer, where the polymer blocks and grooves increase contact area and prevent displacement by allowing the contact to be inserted into the grooves and slots, and the polymer blocks serve as cost-effective base materials for electroplating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional gold bump structure is used, then the bonding process is simple, but the contact area is insufficient and coupling strength is degraded
Solution Approach 1:
The patent transitions from a conventional flat bump structure to a three-dimensional structure with grooves and slots. The grooves extend vertically into the bump, creating additional surfaces for contact insertion. This dimensional change transforms a two-dimensional contact interface into a multi-level three-dimensional interface, significantly increasing the effective contact area and coupling strength.
Solution Approach 2:
The bump structure is segmented into multiple functional zones: a flat top surface for initial contact, grooves for mechanical interlocking, and slots for additional anchoring. This segmentation allows different portions of the contact to engage with different features of the bump, distributing the bonding stress and enhancing overall coupling strength through multiple engagement points.
2Reliability
If a conventional gold bump structure is used, then the manufacturing process is straightforward, but displacement phenomenon occurs during coupling
Solution Approach 1:
The grooves and slots are pre-formed in the bump structure before bonding, creating predetermined pathways that guide and constrain the contact during the bonding process. This preliminary structural preparation prevents displacement by establishing mechanical interlocks in advance, so that when bonding occurs, the contact is naturally guided into the correct position without lateral movement.
Solution Approach 2:
The patent employs a polymer-based bump material that exhibits flexible deformation characteristics. The polymer can elastically deform during the bonding process to accommodate slight misalignments, then recover to maintain precise positioning. This flexibility provides a cushioning effect that prevents rigid displacement while maintaining reliable electrical and mechanical contact.
3Ease of manufacture
If a conventional gold bump structure is used, then the structure is simple, but production cost is higher
Solution Approach 1:
The patent replaces expensive gold material with a polymer-based composite material that is significantly cheaper while maintaining or improving functional performance. The polymer bump with its engineered groove and slot structure provides equivalent or superior mechanical interlocking and electrical conductivity at a fraction of the material cost, making the bump structure more economically viable for mass production.
Solution Approach 2:
The bump structure utilizes a composite material system combining polymer matrix with conductive fillers or metallization layers. This composite approach leverages the cost advantages of polymer materials while incorporating conductive elements to achieve the necessary electrical properties. The composite structure also enables the formation of complex geometries like grooves and slots through conventional polymer processing techniques, reducing manufacturing complexity.
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 enhanced contact area and structural design improve coupling strength and prevent displacement, while reducing production costs by using polymer blocks for electroplating, and the design also prevents short circuits by allowing anisotropic conductive films to flow freely.
Implementation Method 1
The bump structure comprises a first polymer block, a second polymer block, a first groove, an under bump metallurgy layer and a connection metal layer... The first groove is located between the first polymer block and the second polymer block and reveals the bond pad... a second groove, a third connection slot and a fourth connection slot are formed on the under bump metallurgy layer
Implementation Method 2
the bump structure may utilize the first polymer block and the second polymer block as base materials for cost savings of electroplating
Implementation Method 3
the groove may increase flows of anisotropic conductive film located between the bump and the glass substrate to prevent gathering of the conductive particles of the anisotropic conductive film between adjacent bumps to lead a short phenomenon
Data Source
AI summary
A bump structure comprises a first polymer block, a second polymer block, a first groove, an under bump metallurgy layer and a connection metal layer, wherein the first polymer block and the second polymer block are individual blocks. The first polymer block comprises a first connection slot, and the second polymer block comprises a second connection slot communicated with the first groove and the first connection slot. The under bump metallurgy layer covers the first polymer block and the second polymer block to form a second groove. The connection metal layer covers the under bump metallurgy layer to form a third groove, wherein the under bump metallurgy layer covers a first coverage area of the first polymer block and a second coverage area of the second polymer block and reveals a first exposure area of the first polymer block and a second exposure area of the second polymer block.