Micro Bump Structure for Narrow-Pitch Thermal and Current Control
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Solution Overview
Problem
Conventional flip-chip bonding methods using solder bumps face challenges with narrow terminal pitches, leading to increased current density and thermal energy density in bump connection parts, which can result in short-circuits and difficulties in the underfill process.
Innovation Solution
The use of micro bumps with an electrically conductive material part and a bonding material part, formed within through-holes of an anodic aluminum oxide film, which includes fine trenches on the side surfaces and a seed layer to improve electrical and thermal conductivity while minimizing short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pitch between solder bumps is reduced to accommodate narrower terminal pitch, then the number of input/output terminals can be increased, but the current density and thermal energy density in the bump connection part increase
Solution Approach 1:
The solder bump is segmented into multiple parts: a first bonding material part, an electrically conductive material part, and a second bonding material part. This segmentation allows the electrically conductive material part to have a larger cross-sectional area for reduced current density, while the bonding material parts provide adequate bonding area, thus resolving the contradiction between increased terminal quantity and maintained reliability.
Solution Approach 2:
The invention uses composite material structure combining different materials (solder material and electrically conductive material) with different properties. The solder material provides bonding functionality, while the electrically conductive material provides low resistance and high current carrying capacity, thus maintaining reliability even with reduced pitch.
2Reliability
If the size of the solder bump is reduced to prevent short-circuits, then the risk of short-circuit between adjacent bumps is reduced, but the distance between chip and substrate becomes too short for underfill process
Solution Approach 1:
The bump structure is segmented vertically into multiple functional parts with different dimensions. The electrically conductive material part has larger dimensions to prevent short-circuits, while the bonding material parts are positioned to provide adequate spacing for underfill injection, thus resolving the contradiction between short-circuit prevention and manufacturability.
Solution Approach 2:
The invention changes the dimensional distribution of the bump structure by extending it in the vertical direction with multiple parts rather than uniformly reducing all dimensions. This allows maintaining adequate horizontal spacing for underfill while controlling vertical dimensions for short-circuit prevention.
3Quantity of substance
If the pitch between terminals is narrowed to increase integration, then the degree of integration is improved, but the current density and thermal energy density increase leading to potential short-circuits
Solution Approach 1:
The multi-part bump structure segments the current path and heat dissipation path. The electrically conductive material part with larger cross-section handles high current density, while the bonding material parts provide thermal management interfaces, thus enabling narrow pitch while controlling harmful thermal and electrical effects.
Solution Approach 2:
The electrically conductive material part acts as an intermediary between the bonding material parts, providing a low-resistance path for current and thermal energy. This intermediary structure reduces the harmful effects of high current density and thermal energy density that would otherwise occur in narrow pitch configurations.
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 configuration allows for effective electrical connection and heat dissipation while maintaining a narrow pitch between terminals, reducing the risk of short-circuits and enhancing the reliability of the semiconductor package and display devices.
Implementation Method 1
a body made of an anodic aluminum oxide film having a plurality of through-holes
Implementation Method 2
an electrically conductive material part
Implementation Method 3
the internal heat can be rapidly dissipated by distributing the heat dissipation path
Data Source
AI summary
The present invention relates to a micro bump, which is capable of coping with a narrow pitch between terminals and preventing an increase in current density and thermal energy density at a bump connection portion, and to an interposer for electrical connection having same, a semiconductor package, a multi-layer stacked semiconductor device, and a display. The micro bump may be manufactured using: an electrically conductive material part forming step of forming an electrically conductive material part inside a through hole provided in a body made of an anodized film; and a bonding material part forming step of forming a bonding material part on at least a portion of an upper portion and a lower portion of the electrically conductive material part.