Micro-Connection Structure With Insulating Ring Gap
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Solution Overview
Problem
Micro-bump technologies face challenges in enhancing bonding strength and reliability, particularly in fine-pitch micro-bump packages, where existing methods struggle to maintain electrical performance and connection reliability within smaller form factors.
Innovation Solution
The manufacturing process involves forming a substrate with metallic contacts, a patterned insulating layer, a barrier layer, and a filling layer, followed by the sequential deposition of a bonding enhancement layer and a seed layer. This process includes etching to create openings, forming bumps on the seed patterns, and ensuring a gap between the bumps and the barrier layer to isolate them, which enhances bonding and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If micro-bump technologies are used to increase input/output density in smaller form factor packages, then the packaging density is improved, but the bonding strength and reliability deteriorate
Solution Approach 1:
The bonding enhancement layer is segmented into multiple layers with different materials (e.g., titanium layer and copper layer) that perform different functions: the titanium layer provides adhesion to the substrate while the copper layer provides electrical conductivity and bonding surface for the bump. This segmentation allows each layer to optimize its specific function, thereby maintaining reliability while achieving high packaging density.
Solution Approach 2:
The bonding enhancement layer acts as an intermediary between the substrate and the bump, mediating the bonding interface. This intermediate layer resolves the contradiction by providing a specialized bonding surface that enhances reliability without increasing the overall package size, thus maintaining high packaging density while improving bonding strength.
2Productivity
If fine-pitch micro-bump structures are implemented to increase connection density, then the input/output density is improved, but the manufacturing precision requirements worsen
Solution Approach 1:
The bonding enhancement layer is formed preliminarily before the bump formation process. This preliminary action prepares the substrate surface with optimal bonding characteristics in advance, which simplifies subsequent bump formation processes and reduces the precision requirements for fine-pitch fabrication by providing a pre-optimized bonding interface.
Solution Approach 2:
The bonding enhancement layer changes the surface parameters of the substrate (such as surface energy, roughness, and chemical composition) to optimize bonding conditions. This parameter change allows for reliable bonding at fine-pitch dimensions without requiring extremely tight manufacturing tolerances, thereby enabling high input/output density while managing manufacturing precision requirements.
3Area of moving object
If the bump is placed close to the barrier layer to maximize space utilization, then the packaging density is improved, but the risk of shorts increases
Solution Approach 1:
The insulating ring acts as an intermediary barrier between the bump and the barrier layer, preventing direct contact that could cause short circuits. This intermediary structure allows the bump to be positioned close to the barrier layer for space efficiency while maintaining electrical isolation, thus resolving the contradiction between space utilization and short circuit risk.
Solution Approach 2:
The insulating ring extracts the harmful electrical conductivity from the bonding interface region by introducing an electrically insulating material in the critical area between the bump and barrier layer. This extraction of conductivity prevents shorts while allowing close spacing for maximum space utilization.
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 described process improves the bonding strength and reliability of micro-connections by providing a clean bonding surface and accommodating extra bonding material, reducing the risk of shorts, and is suitable for high-density, fine-pitch micro-connection structures, contributing to better electrical performance and cost-effectiveness.
Implementation Method 1
A bonding enhancement layer and a seed layer are sequentially formed on the patterned filling layer and on the exposed metallic contacts
Implementation Method 2
A bonding enhancement layer and a seed layer are sequentially formed on the patterned filling layer and on the exposed metallic contacts
Implementation Method 3
The bonding enhancement layer and the seed layer outside the openings and on the patterned filling layer are removed
Implementation Method 4
Bumps are formed on the seed patterns in the openings
Data Source
AI summary
A micro-connection structure is provided. The micro-connection structure includes an under bump metallurgy (UBM) pad, a bump and an insulating ring. The UBM pad is electrically connected to at least one metallic contact of a substrate. The bump is disposed on the UBM pad and electrically connected with the UBM pad. The insulating ring surrounds the bump and the UBM pad. The bump is separate from the insulating ring with a distance and the bump is isolated by a gap between the insulating ring and the bump.