Staggered Probing Semiconductor Bumps Using Segmented Irregular Structures
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Solution Overview
Problem
Conventional semiconductor devices face issues with electrical shorts and insufficient bonding strength due to reduced bump pitch and width, making it difficult to probe and bond chips effectively, especially when bump spacing is below 10 μm and width is below 15 μm, leading to testing failures and increased costs with additional redistribution and passivation layers.
Innovation Solution
The semiconductor device features a combination of regular and irregular bumps arranged in a staggered pattern with narrow and probed portions, allowing for higher density bump placement without electrical shorts and maintaining bonding strength, eliminating the need for additional redistribution and passivation layers by using a single layer of leads and UBM pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the bump pitch is reduced to increase the number of bumps on the chip, then the chip capacity increases, but electrical shorts between bumps occur and bonding strength becomes insufficient
Solution Approach 1:
The bump structure is segmented into two functional parts: a narrow bonding portion for electrical connection and a wider probed portion for testing. This segmentation allows the bonding portion to maintain small pitch for high density while the probed portion provides sufficient width for reliable probing and bonding operations.
Solution Approach 2:
Different parts of the bump structure have different local qualities: the bonding portion has narrow width optimized for high-density electrical connection, while the probed portion has wider width optimized for mechanical probing and bonding strength. This local quality differentiation resolves the contradiction between density and reliability.
2Manufacturing precision
If the bump width is reduced to achieve finer bump pitch, then the chip density increases, but the probing becomes difficult and testing fails
Solution Approach 1:
The bump is divided into a narrow bonding portion and a wider probed portion. The probed portion provides adequate width for probe card contact and testing operations, while the bonding portion maintains the fine pitch required for high-density interconnects.
Solution Approach 2:
The bump structure extends in the width dimension beyond what is needed for bonding, creating a protruding probed portion. This dimensional extension provides sufficient probing surface area while maintaining the fine pitch in the spacing dimension between bumps.
3Ease of operation
If additional redistribution layers and passivation layers are added to enable staggered probing, then the probing issue is resolved, but the manufacturing complexity and cost increase
Solution Approach 1:
The probing function is extracted from the bonding structure by adding a separate probed portion to each bump. This allows probing to occur at a different location (the wider probed portion) than bonding (the narrow bonding portion), enabling staggered probing without requiring additional redistribution or passivation layers.
Solution Approach 2:
The irregular bump structure serves multiple functions: the narrow bonding portion provides electrical connection, while the wider probed portion provides testing capability. This multi-functionality is achieved within the same bump structure without requiring separate layers for bonding and probing.
Data Source
AI summary
A semiconductor device has a plurality of bumps in a same row for staggered probing. The bumps in a same row are disposed on a chip and include a plurality of regular bumps and a plurality of irregular bumps. The regular bumps and the irregular bumps are interspersed in a same pitch. Along a defined line, the widths of the irregular bumps are narrower than the ones of the regular bumps for fine pitch applications. Additionally, the irregular bumps have a plurality of integral probed portions far away the line, top surfaces of which are expanded such that probed points can be defined on the probed portions for staggered probing.