Semiconductor Package Bump Layout for Chip Alignment During Bonding
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Solution Overview
Problem
Misalignment of semiconductor chips during the bonding process due to the sweep of bumps in semiconductor packages is a persistent issue that existing technologies have not adequately addressed.
Innovation Solution
The proposed semiconductor package design incorporates a bump structure with a connection bump and a dummy bump of different thicknesses, where the dummy bump is electrically insulated and serves as an alignment pattern, surrounded by a conductive material layer, to minimize misalignment by utilizing surface tension during the reflow process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bump structure is used for bonding semiconductor chips, then the bonding process can be completed, but misalignment of chips occurs due to sweep of the bump
Solution Approach 1:
The bump structure is segmented into multiple types: connection bumps for electrical connection and dummy bumps for alignment reference. This segmentation allows the alignment function to be separated from the connection function, enabling precise chip positioning without interference from bump sweep during bonding.
Solution Approach 2:
Dummy bumps serve as intermediary alignment reference points between the bonding process and the final chip alignment. These dummy bumps provide a stable reference pattern that mediates the positioning process, allowing accurate alignment to be achieved despite the sweep of connection bumps during bonding.
2Ease of manufacture
If the thickness of all bumps is made uniform, then the manufacturing process is simplified, but alignment precision is reduced due to bump sweep
Solution Approach 1:
Different regions of the bump structure have different thicknesses tailored to their specific functions. Connection bumps have optimized thickness for electrical connection, while dummy bumps have greater thickness to serve as stable alignment references. This local differentiation of quality enables both manufacturing efficiency and alignment precision.
Solution Approach 2:
The bump structure employs asymmetric thickness design where dummy bumps are intentionally made thicker than connection bumps. This asymmetry creates distinct alignment reference points that are not affected by the sweep of thinner connection bumps, thereby maintaining alignment precision while allowing varied manufacturing parameters.
3Manufacturing precision
If dummy bumps with larger thickness are used for alignment, then alignment precision is improved, but the device complexity increases
Solution Approach 1:
The dummy bumps serve multiple functions: they act as alignment reference patterns, provide structural support, and define bonding boundaries. By making these elements multi-functional, the patent reduces the need for separate alignment markers, thereby limiting the increase in device complexity while maintaining improved alignment precision.
Solution Approach 2:
The alignment reference function is merged with the existing bump structure by incorporating dummy bumps into the same layer and formation process as connection bumps. This merging approach allows alignment functionality to be added without creating entirely separate structures, thus limiting the increase in device 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
This design effectively reduces defects caused by misalignment, improves assembly yield, and enhances the bonding process by using the dummy bump as an alignment pattern, ensuring precise chip positioning.
Implementation Method 1
The proposed semiconductor package design incorporates a bump structure with a connection bump and a dummy bump of different thicknesses, where the dummy bump is electrically insulated and serves as an alignment pattern, surrounded by a conductive material layer, to minimize misalignment by utilizing surface tension during the reflow process.
Data Source
AI summary
A semiconductor package comprising: a first semiconductor chip extending in each of first and second directions that intersect each other; a second semiconductor chip on the first semiconductor chip in a third direction perpendicular to the first and second directions, wherein the second semiconductor chip includes a first area and a second area that is adjacent to and extends around the first area; and a bump structure and a conductive material layer between the first and second semiconductor chips, wherein the conductive material layer is on the bump structure, wherein the bump structure includes a first bump structure overlapping the first area in the third direction, and a second bump structure overlapping the second area in the third direction, wherein the first and second bump structures are spaced apart from each other, and a thickness of the second bump structure is larger than a thickness of the first bump structure.