Bevel Pad Row for High-Density Chip Wire Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional IC chip packaging techniques face limitations in improving pad arrangement density due to the width requirements of corner wire bonding areas, which restrict the efficient use of space and lead to suboptimal design configurations.
Innovation Solution
A chip structure with a bevel pad row is introduced, where the corner wire bonding area features a bevel edge with an acute angle, allowing for a greater number of bevel pads than middle pad rows, thereby optimizing the pad arrangement density by reducing the corner wire bonding area width and increasing the middle wire bonding area length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the corner wire bonding area width is increased to accommodate more corner pads, then the number of corner pads increases, but the middle wire bonding area length decreases and pad arrangement density cannot be improved
Solution Approach 1:
The patent introduces a bevel edge at the corner wire bonding area with an acute angle (30-60 degrees) relative to the side of the active surface, creating a diagonal arrangement for bevel pads. This dimensional change from orthogonal to angular arrangement allows pads to be positioned more efficiently along the bevel edge, increasing the number of accommodable pads without expanding the corner area width, thereby preserving the middle wire bonding area length.
Solution Approach 2:
The patent employs asymmetric positioning of pads within the corner wire bonding area by creating a bevel edge that forms an acute angle with the side of the active surface. This asymmetric configuration allows the bevel pads to be arranged along the angled bevel edge rather than in a standard orthogonal grid, enabling denser pad placement within the same area and resolving the contradiction between increasing pad quantity and maintaining middle area length.
2Length of moving object
If the corner wire bonding area width is reduced to increase middle wire bonding area length, then the middle wire bonding area length increases, but the number of corner pads decreases
Solution Approach 1:
By introducing the bevel edge with an acute angle, the patent creates an additional spatial dimension for pad arrangement. The bevel pads are positioned along this angled edge, which effectively increases the usable length for pad placement without requiring additional width. This allows the corner area width to be reduced while still accommodating the required number of pads, thereby enabling the middle wire bonding area length to increase.
Solution Approach 2:
The bevel edge introduces a curved or angled boundary rather than a straight orthogonal edge, optimizing the use of corner space. This curved/angular configuration allows pads to be arranged along the bevel edge at optimal spacing, maximizing the number of pads that can fit within a reduced width constraint, thus enabling both sufficient pad quantity and increased middle area length.
3Reliability
If the spacing between adjacent corner pads is increased to 85 μm for successful wire bonding, then wire bonding can be performed successfully, but the corner wire bonding area width must be large (greater than 765 μm) which reduces pad arrangement density
Solution Approach 1:
The patent positions bevel pads along a diagonal bevel edge rather than in a linear orthogonal arrangement. This angular configuration allows the effective pad length to be extended along the bevel edge direction, enabling adequate spacing (≥85 μm) between pads while fitting more pads within the same corner area width, thus maintaining both wire bonding reliability and higher pad density.
Solution Approach 2:
The bevel edge creates an optimized geometric configuration that allows pads to be arranged at optimal spacing intervals along the angled boundary. This curved/angular arrangement maximizes space utilization by positioning pads along the most efficient path, ensuring minimum spacing requirements are met while accommodating the maximum number of pads within the available corner area, thereby achieving both reliability and density.
Data Source
AI summary
A chip structure with a bevel pad row comprises a substrate, a plurality of middle pad rows, and a bevel pad row. The substrate has an active surface including a middle wire bonding area and a corner wire bonding area. The middle wire bonding area is adjacent to a side of the active surface. The corner wire bonding area is adjacent to the side and a end of the middle wire bonding area, and the corner wire bonding area has a bevel edge with an acute incline angle to the side. The middle pad rows are disposed in the middle wire bonding area, and the bevel pad row is disposed along the bevel edge of the corner wire bonding area. The bevel pad row has a plurality of bevel pads, and the quantity of which is greater than that of the middle pad rows in the middle wire bonding area.