Semiconductor Package Plating Lead Line Segmentation for ECM Prevention
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Solution Overview
Problem
Semiconductor packages face issues with electro-chemical migration (ECM) failure due to variations in external environments like humidity and temperature, and the presence of plating lines acting as undesirable transmission lines that degrade signal transmission speed and integrity.
Innovation Solution
The semiconductor package design includes a package substrate with a reduced total length of plating lead lines, featuring a plating lead line connected only to non-signal lines and provisional bridge lines that are cut away after electrolytic plating, creating opening holes to electrically disconnect the dam portions and prevent electro-chemical migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plating lead lines are extended to improve electrical connection, then electrical conductivity is improved, but electro-chemical migration failure risk increases
Solution Approach 1:
The plating lead line is segmented into multiple sections by introducing opening holes that electrically disconnect portions of the line. This segmentation prevents continuous electro-chemical migration paths while maintaining necessary electrical connections through selective routing, thereby resolving the contradiction between ensuring electrical reliability and preventing ECM failure.
Solution Approach 2:
Problematic sections of the plating lead line are extracted or removed by creating opening holes at strategic locations. This extraction eliminates the harmful continuous conductive path that enables electro-chemical migration, while the remaining portions maintain essential electrical connectivity through alternative routing via conductive vias.
2Reliability
If plating lead lines are used to improve bondability and conductivity, then electrical performance is improved, but signal integrity degrades due to stubs and reflection paths
Solution Approach 1:
The plating lead line structure is segmented into electrically isolated sections using opening holes. This segmentation eliminates continuous transmission line paths that would act as stubs and cause signal reflections, while maintaining necessary electrical connections through controlled routing via conductive vias to bonding fingers and conductive lines.
Solution Approach 2:
The harmful transmission line portions are extracted by removing material to form opening holes. This extraction eliminates the stub structures that cause signal reflections and degradation, while preserving essential electrical connectivity through the remaining plating lead line sections connected via conductive vias.
3Reliability
If opening holes are introduced to prevent ECM, then ECM resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The substrate structure is segmented by introducing opening holes that create electrical disconnections in the plating lead line. While this adds structural elements, the segmentation is achieved through standard PCB fabrication processes, and the resulting ECM prevention outweighs the moderate increase in manufacturing complexity.
4Reliability
If plating lead lines are connected to multiple conductive lines, then electrical connectivity is improved, but ECM pathways increase
Solution Approach 1:
The plating lead line is segmented into electrically isolated sections by introducing opening holes at strategic locations. This segmentation breaks continuous ECM migration paths between multiple conductive lines while maintaining necessary electrical connectivity through selective routing via conductive vias to bonding fingers and specific conductive lines.
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 suppresses ECM failure and reduces the length of plating lead lines, enhancing signal integrity and operation characteristics by preventing the plating lines from acting as signal stubs or reflection paths.
Implementation Method 1
The plating layer may improve the bondability between the interconnection lines and the connectors as well as the electric conductivity of the interconnection lines
Implementation Method 2
provisional bridge lines that are cut away after electrolytic plating
Data Source
AI summary
The semiconductor package includes a package substrate. The package substrate includes a base layer, a first group of conductive lines disposed on a first surface of the base layer, and a second group of conductive lines disposed on a second surface of the base layer and electrically connected to respective ones of the first group of conductive lines. The package substrate further includes a plating lead line connected to one of the first group of conductive lines.