Alternating Bond Pad Orientation for Fine Pitch Wire Bonding
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Solution Overview
Problem
The semiconductor industry faces challenges in increasing the number of input/output (I/O) pads on devices while maintaining an acceptable bonding power window and electrical properties, as finer gauge wires used for smaller bond pads exhibit worse electrical properties and there is a limit to how fine the bonding wire can be for bonding semiconductor devices.
Innovation Solution
The bonding pads are positioned in an alternating orientation, allowing bond balls to be on opposite sides of adjacent pads, enabling interlocking configurations that reduce pad pitch without changing bond ball or wire diameter, thereby increasing the number of connections while maintaining electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If bond pad size is reduced to increase the number of I/O pads, then the number of connections increases, but the bonding power window becomes narrower and electrical properties deteriorate
Solution Approach 1:
The patent transitions from a linear arrangement of bond pads to a two-dimensional grid pattern where pads are distributed across both length and width dimensions. This dimensional expansion allows increased I/O pad density without reducing individual pad size, thereby maintaining bonding power window and electrical properties while achieving higher connection counts.
Solution Approach 2:
The patent implements overlapping bond pad structures where adjacent pads share common regions. This nesting approach allows pads to be positioned closer together than their individual diameters would suggest, effectively increasing the number of pads per unit area without compromising the bonding characteristics of each individual pad.
2Reliability
If finer gauge wire is used to accommodate smaller bond pads, then bonding power window improves, but electrical properties worsen
Solution Approach 1:
By distributing pads in a two-dimensional grid rather than reducing pad size linearly, the invention maintains larger pad dimensions and thus supports thicker wire gauges. This dimensional reorganization allows the use of coarser wire (which has better electrical properties) while still achieving high I/O density through spatial distribution.
3Ease of manufacture
If traditional linear bond pad arrangement is used, then manufacturing is simple, but pad pitch cannot be reduced below 50 μm
Solution Approach 1:
The patent extends the traditional one-dimensional linear pad arrangement into a two-dimensional grid pattern. This spatial reorganization breaks the linear pitch constraint and allows pads to be positioned at regular intervals in both x and y directions, achieving effective pitch reduction to approximately 25 μm while maintaining manufacturability through the regularity of the grid pattern.
Solution Approach 2:
The overlapping pad structures create a nested arrangement where pads share common regions. This nesting reduces the effective pitch between adjacent pads by utilizing shared spaces, allowing pitch reduction below the traditional 50 μm limit while maintaining manufacturing feasibility through the systematic overlapping pattern.
Data Source
AI summary
A bonding pad design is disclosed that includes one or more pad groups on a semiconductor device. Each pad group is made up of two or more bonding pads that have an alternating orientation, such that adjacent bonding pads have their bond ball on opposite sides in relation to the adjacent bonding pad.