TAB Package Pad Layout for Signal Integrity
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Solution Overview
Problem
Existing fine pitch TAB packages face challenges with signal interference and manufacturing defects such as short circuits due to limited routing space and thin lead wires, which affect product reliability and performance.
Innovation Solution
A semiconductor chip and film configuration for TAB packages with specific pad and lead arrangements that increase routing space and lead width, including input and output pads and leads connected in a manner that maximizes space utilization and minimizes interference, allowing for thicker leads and reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If routing space between lead wires is decreased to achieve finer pitch, then device miniaturization is improved, but signal interference and short circuit defects increase
Solution Approach 1:
The patent transitions from planar routing to three-dimensional routing by utilizing the vertical dimension through lead wire bends and loops. This allows signals to be routed in multiple layers and directions, effectively increasing routing space without increasing the device footprint, thereby maintaining fine pitch while reducing signal interference and short circuit risks.
Solution Approach 2:
The patent employs nested routing structures where lead wires are arranged in concentric patterns and nested loops. Inner lead wires are positioned within the spatial envelope of outer lead wires, allowing multiple signals to be routed through the same general area without interfering with each other, thus achieving fine pitch while maintaining adequate routing space for reliability.
2Volume of moving object
If lead wire width is decreased to achieve finer pitch, then device miniaturization is improved, but lead wire cracks and manufacturing defects increase
Solution Approach 1:
The patent uses vertical routing with lead wire bends and loops to achieve fine pitch without reducing lead wire width. By utilizing the third dimension for routing, the lead wires can maintain adequate thickness for mechanical strength while still achieving compact device dimensions through optimized spatial arrangement.
3Reliability
If routing space is increased to avoid signal interference, then product reliability is improved, but device size increases
Solution Approach 1:
The patent employs nested routing where inner lead wires are positioned within the spatial envelope of outer lead wires. This nesting arrangement allows adequate routing space and signal separation for reliability while maintaining a compact overall device footprint, as the nested structure efficiently utilizes the available volume without requiring proportional increases in device dimensions.
Solution Approach 2:
The patent utilizes vertical routing with multiple layers and three-dimensional lead wire arrangements to provide adequate routing space for signal integrity. This approach achieves improved reliability through better signal separation while maintaining fine pitch and compact device size by efficiently using the vertical dimension rather than expanding the planar footprint.
Data Source
AI summary
A semiconductor chip for a TAB package includes a surface including a set of input pads connected to internal circuitry of the chip and for receiving external signals The surface includes output pads. A plurality of input pads are adjacent a first edge and are in a first row substantially parallel to the first edge and extending in a first direction; a plurality of first output pads are adjacent a second edge, and are in a second row substantially parallel to the second edge and extending in the first direction; and a plurality of second output pads are located between the first row and the second row. The plurality of second output pads include first and second outermost pads located a certain distance from a respective third edge and fourth edge, and first and second inner pads located a greater distance from the respective third edge and fourth edge.