Non-Uniform Die Separation Ring for Large-Aspect-Ratio Wafers

Solution Overview

Problem

In semiconductor wafer dicing, uniform expansion can lead to uneven spacing between dies with large aspect ratios, causing incomplete separation and recognition issues during image processing.

Innovation Solution

A die separation ring with an annular body that causes non-uniform expansion of the dicing tape by varying elevations on its surface, allowing for differential expansion in different directions to achieve uniform die spacing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If uniform expansion is applied to the dicing tape, then the expansion process is simple and consistent, but the spacing between dies becomes uneven for large aspect ratio dies

Engineering Contradiction:

Improvedie spacing uniformityVSAvoidexpansion ring structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The expansion ring incorporates a non-uniform top surface with varying elevations (first planar surface at higher elevation, second planar surface at lower elevation) to create differential expansion in different radial directions. This local variation in surface height compensates for the different expansion requirements of long sides versus short sides of large aspect ratio dies, achieving uniform die spacing through non-uniform local expansion characteristics.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The expansion ring deliberately introduces asymmetric geometry by having different elevations at different angular positions around the central axis. The first planar surface extends in a first direction with a first elevation, while the second planar surface extends in a second direction with a second elevation that is lower. This asymmetric structure creates the necessary non-uniform expansion pattern to address the symmetric problem of die spacing uniformity.

Inventive Principle:

Principle #4Asymmetry

2Reliability

If the dicing tape is expanded uniformly in all directions, then the expansion process is straightforward, but dies with large aspect ratios do not separate uniformly

Engineering Contradiction:

Improvedie separation completenessVSAvoidexpansion ring geometry

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The expansion ring incorporates a non-uniform top surface with varying elevations (first planar surface at higher elevation, second planar surface at lower elevation) to create differential expansion in different radial directions. This local variation in surface height compensates for the different expansion requirements of long sides versus short sides of large aspect ratio dies, achieving uniform die spacing through non-uniform local expansion characteristics.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If uniform expansion is used, then the process is simple to control, but image recognition fails due to uneven die spacing

Engineering Contradiction:

Improvedie spacing consistencyVSAvoidexpansion ring surface structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The expansion ring incorporates a non-uniform top surface with varying elevations (first planar surface at higher elevation, second planar surface at lower elevation) to create differential expansion in different radial directions. This local variation in surface height compensates for the different expansion requirements of long sides versus short sides of large aspect ratio dies, achieving uniform die spacing through non-uniform local expansion characteristics.

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 die separation ring ensures more uniform spacing between dies with large aspect ratios, facilitating complete separation and improving die recognition during image processing.

Implementation Method 1

causes an expansion material (e.g., dicing tape) on which a semiconductor wafer has been mounted to expand a first degree or amount in a first direction and a second degree or amount in a second direction

Methodology Applied

Scientific EffectDifferential expansion: Thermal Expansion

Data Source

PatentUS12347733B2Die separation ring for wafers having a large die aspect ratio

Publication Date: 2025.07.01 SANDISK TECHNOLOGIES LLC

AI summary

A die separation ring that causes non-uniform expansion of a semiconductor wafer during a semiconductor wafer expansion process. The die separation ring includes an annular body that extends about a central axis. The annular body of the die separation ring includes a first portion having a first elevation and a second portion having a second elevation that is lower than the first elevation. A third portion extends between the first portion and the second portion forming a transition between the first portion and the second portion.