Semiconductor Wafer Ring Support Structure for Thinning Stability

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Solution Overview

Problem

Existing methods for thinning semiconductor wafers, such as back grinding, are costly and can damage the wafers due to issues with adhesion of dicing tape and grinding wheel performance, leading to instability and increased breakage.

Innovation Solution

A ring support structure with a beveled or stepped inner edge is formed on the semiconductor wafer, allowing for improved adhesion of dicing tape and reducing grinding wheel wear, thereby enhancing the thinning process while minimizing air gaps and contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If back grinding technique is used to thin semiconductor wafer, then wafer thickness is reduced, but dicing tape adhesion fails and wafer stability decreases

Engineering Contradiction:

Improvewafer thicknessVSAvoidwafer stability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent divides the peripheral region into discrete support structures (rims or lips) spaced around the wafer perimeter, creating segmented support zones. This segmentation allows dicing tape to adhere to multiple separate surfaces rather than a continuous peripheral surface, improving adhesion reliability while maintaining thinness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The support structures are formed on the wafer before the thinning process begins. This preliminary formation of adhesion surfaces ensures that when dicing tape is applied after thinning, there are pre-existing surfaces for reliable attachment, preventing the adhesion failure that occurs when attempting to attach tape to a fully thinned smooth perimeter.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If conventional grinding wheel is used to thin support structure, then grinding process is efficient, but grinding wheel wear increases and productivity decreases

Engineering Contradiction:

Improvegrinding efficiencyVSAvoidgrinding wheel service life

Core Design Contradiction:

ProductivityVSDuration of action of moving object

Solution Approach 1:

The patent changes the geometric parameters of the support structure by forming beveled surfaces at specific angles (e.g., 45 degrees) on the rims or lips. This angular geometry allows the grinding wheel to contact the support structure in a manner that reduces lateral forces and wear on the wheel, extending its service life while maintaining efficient material removal.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The beveled surfaces introduce curved or angled contact zones between the grinding wheel and support structure, replacing flat perpendicular surfaces. This curvature optimizes the contact mechanics during grinding, distributing wear more evenly across the wheel surface and reducing premature wheel degradation.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Ease of manufacture

If perpendicular lip edge is formed, then manufacturing is simple, but air gaps form and contamination increases

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidair gaps and contamination

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the perpendicular (90-degree) lip edge with beveled surfaces at angled orientations. This angular modification eliminates sharp corners where air gaps and slurry would become trapped, creating smooth transitions that prevent contamination accumulation while remaining manufacturable through standard grinding or etching processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Duration of action of moving object

If large grit grinding wheel is used, then grinding wheel wear is reduced, but wafer damage increases

Engineering Contradiction:

Improvegrinding wheel service lifeVSAvoidwafer damage

Core Design Contradiction:

Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies different grit sizes to different regions of the grinding wheel based on the local requirements of the support structure geometry. Coarser grit is used for initial material removal from the beveled surfaces, while finer grit is applied for final surface finishing, optimizing both wheel life and wafer integrity without requiring uniformly large grit across the entire wheel.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The beveled or stepped ring support structure improves the stability and reduces the cost of thinning semiconductor wafers by enhancing tape adhesion and grinding efficiency, decreasing breakage and contamination.

Implementation Method 1

a ring support structure is formed from a peripheral portion of a semiconductor wafer

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 2

improved adhesion of dicing tape

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS8292690B2Thinned semiconductor wafer and method of thinning a semiconductor wafer

Publication Date: 2012.10.23 SEMICON COMPONENTS IND LLC

AI summary

A thinned semiconductor wafer and a method for thinning the semiconductor wafer. A semiconductor wafer is thinned from its backside to form a cavity in a central region of the backside of the semiconductor wafer. Forming the cavity also forms a ring support structure in a peripheral region of the semiconductor wafer. The ring support structure has an inner edge and an outer edge. The inner edge may be beveled or have a stepped shape.