Wafer Scribe Lane Slit Patterns for Sawing Stress Relief
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Solution Overview
Problem
Conventional sawing processes for wafers result in chipping and peeling of chips due to mechanical stress, particularly affecting passivation films and interlayer insulating films, leading to defects and potential short circuits in multi-chip packages.
Innovation Solution
A wafer design featuring scribe lanes with engraved slit patterns on the passivation film, which disperses mechanical stress and prevents peeling by acting as barriers against lateral stress transmission, while maintaining the integrity of monitoring patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the passivation film is completely opened along the scribe lanes to prevent mechanical stress transmission, then chipping is reduced, but peeling occurs causing short circuits
Solution Approach 1:
The passivation film is segmented into multiple discrete slit patterns rather than being completely opened. These slits are distributed along the scribe lane to interrupt stress transmission paths while leaving portions of the passivation film intact to maintain electrical isolation and prevent peeling of metal layers.
Solution Approach 2:
The passivation film structure is made non-uniform by introducing slit patterns at specific locations along the scribe lane. The slits are strategically positioned to provide stress relief where needed while maintaining continuous coverage in areas critical for preventing peeling and short circuits.
2Strength
If a hard passivation film is used to protect the chip, then mechanical strength is improved, but stress transmission causes peeling and defects
Solution Approach 1:
The continuous hard passivation film is segmented into discrete sections by engraving slits. This segmentation allows the hard film to maintain its protective strength while the slits interrupt the continuous stress transmission path that would otherwise cause peeling at the film-chip interface.
Solution Approach 2:
The slit patterns act as intermediary stress-breaking elements within the passivation film structure. They serve as stress release zones that prevent the accumulation and transmission of mechanical stress from the sawing process to the underlying metal layers and chip structure.
Data Source
AI summary
A wafer that is less susceptible to chipping or peeling during a sawing process is disclosed. The wafer includes a plurality of chips, scribe lanes formed between the plurality of chips, and a passivation film, which is formed on the plurality of chips and the scribe lanes and has a plurality of perforations, e.g. slit patterns engraved on each scribe lane. A photolithography reticle and method of manufacturing the wafer are also provided.