Wafer Grinding Spacer Ring to Block Edge Crack Propagation

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Solution Overview

Problem

Cracks during wafer grinding propagate from the edge to the central region, causing severe wafer damage and reduced yield due to external stress.

Innovation Solution

Form a spacer ring within the peripheral zone of the wafer to isolate the central zone from the edge, using a trench filled with a filler to block crack propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If grinding is performed from the back side of the wafer to reduce thickness, then the wafer thickness is reduced and productivity is improved, but cracks occur on the edge of the wafer due to external stress and propagate into the central region causing wafer damage

Engineering Contradiction:

Improvewafer thickness reduction efficiencyVSAvoidwafer integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The wafer is divided into a central zone and a peripheral zone, with the trench and filler creating a physical segmentation that isolates the central region from edge-induced cracks during grinding

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A filler material is introduced as an intermediary substance within the trench structure to act as a stress barrier, preventing crack propagation from the peripheral zone to the central zone during the grinding process

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If external stress is applied to the wafer during grinding, then the grinding process can be performed effectively, but cracks are generated on the edge and propagate into the central region where electronic components are formed

Engineering Contradiction:

Improvegrinding process feasibilityVSAvoidcrack propagation

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The trench and filler structure is formed in advance before grinding to create a preliminary protective barrier that counteracts the harmful effect of stress-induced crack propagation during the subsequent grinding process

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The external stress that would normally cause harmful crack propagation is converted into a beneficial process by using the filler material to absorb and redirect the stress, preventing cracks while maintaining the necessary grinding force

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS20260068573A1Method for grinding a wafer

Publication Date: 2026.03.05 STATS CHIPPAC LTD

AI summary

A method for grinding a wafer is provided. The method comprises: providing a wafer having a back side and a front side opposite to the back side, wherein the wafer further comprises a central zone for accommodating semiconductor units and a peripheral zone surrounding the central zone; forming a trench within the peripheral zone and extending along substantially an entire circumference of the peripheral zone, wherein the trench is exposed from the front side of the wafer; filling the trench with a filler to form a spacer ring within the peripheral zone, wherein the spacer ring isolates the central zone from an edge of the wafer; attaching the wafer onto a platform at the front side of the wafer; and grinding the wafer from the back side of the wafer.