Die Sawing Damage Reduction in Semiconductor Substrates
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Solution Overview
Problem
The existing methods for die sawing in semiconductor substrates often result in mechanical failure and contamination due to cracking of multi-layer structures, especially when using extreme low-k dielectric layers, and metal fragments can dull the sawing blade and worsen cracking.
Innovation Solution
The method involves defining scribe line areas with active and non-active regions, forming a passivation layer over the conductive structures, and removing a portion of the passivation layer within the non-active regions to reduce die-sawing damage, allowing for effective sawing without substantial damage to the die areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a multi-layer interconnect structure with extreme low-k dielectric layers is used to achieve high integration and high speed, then the performance targets are met, but the structure becomes extremely fragile and prone to cracking during sawing
Solution Approach 1:
The scribe line area is divided into active regions (containing metal structures) and non-active regions (without metal structures). This segmentation allows different handling approaches: non-active regions are removed to prevent cracking propagation, while active regions are preserved to maintain electrical functionality. The passivation layer is selectively removed only in non-active regions, creating a segmented structure that balances fragility prevention with functionality preservation.
Solution Approach 2:
The passivation layer is selectively removed only in non-active regions of the scribe line area, while being retained in active regions. This local quality change means that the structural integrity is maintained where metal structures exist (active regions), while potential crack sources are eliminated in non-active regions. The dielectric layers are also selectively thinned or removed in non-active regions, creating localized structural modifications that prevent crack propagation without affecting functional areas.
2Measurement precision
If metal layers are present in scribe line areas for WAT patterns, then electrical measurements can be performed, but metal fragments attach to the blade during sawing, causing dulling and worsening cracking
Solution Approach 1:
Metal structures are completely removed from non-active regions of the scribe line area, eliminating the source of metal fragments that would otherwise attach to the sawing blade. The passivation layer in non-active regions is removed to expose and allow removal of any remaining metal structures. This extraction ensures that only non-metallic materials remain in non-active regions, preventing blade contamination while preserving metal structures in active regions where WAT measurements are performed.
3Reliability
If the passivation layer is retained over the entire substrate including scribe line areas, then complete protection is provided, but cracking of the multi-layer structure occurs during sawing
Solution Approach 1:
The passivation layer is selectively removed in non-active regions before the sawing process occurs. This preliminary action eliminates the structural constraint that would cause cracking during sawing, while preserving the passivation layer in active regions to maintain protection of functional structures. By preparing the structure in advance with selective passivation layer removal, the sawing process can proceed without inducing cracks in the multi-layer interconnect structure.
Data Source
AI summary
A structure includes a substrate having a plurality of scribe line areas surrounding a plurality of die areas. Each of the die areas includes at least one first conductive structure formed over the substrate. Each of the scribe line areas includes at least one active region and at least one non-active region. The active region includes a second conductive structure formed therein. The structure further includes at least one first passivation layer formed over the first conductive structure and second conductive structure, wherein at least a portion of the first passivation layer within the non-active region is removed, whereby die-sawing damage is reduced.