Ion Beam Etching Grid Assemblies for Warping Resistance

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Solution Overview

Problem

Ion beam etching systems face issues with mechanical stress and warping of grid assemblies due to deposition of unwanted material, leading to reduced ion beam uniformity and increased costs from frequent replacements, especially when etching larger wafers.

Innovation Solution

A grid assembly comprising a thicker ground grid member, a thinner negative grid member, and a positive grid member, with optimized spacing between them to maintain ion beam uniformity and structural robustness, allowing for adjustable spacing to adapt to different etching requirements and extend the life of the grid assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a grid assembly is used in ion beam etching systems, then ion beam uniformity and etching performance are improved, but deposition of unwanted material causes mechanical stress and warping that degrades uniformity over time

Engineering Contradiction:

Improveion beam uniformityVSAvoidgrid assembly stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The grid assembly is divided into multiple grid members (first grid member, second grid member, third grid member) with different thicknesses and electrical potentials. This segmentation allows each member to serve specific functions: the thicker first grid member provides structural support to resist warping, while the other members control ion beam uniformity through electrical fields.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different grid members are designed with different local properties - the first grid member has greater thickness for mechanical strength, while the second and third grid members have optimized thickness for electrical field control. This local differentiation allows the system to simultaneously achieve structural stability and ion beam uniformity.

Inventive Principle:

Principle #3Local quality

2Productivity

If grid assemblies are frequently replaced to maintain yield, then ion beam uniformity is maintained, but material costs, labor costs, system down time, and resource waste increase

Engineering Contradiction:

Improvefabrication yieldVSAvoidsystem down time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The grid assembly is designed with a thicker first grid member before deployment, providing enhanced structural strength to resist warping from material deposition. This preliminary reinforcement extends the operational life of the grid assembly, reducing the frequency of replacements and associated system downtime.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The grid members are subjected to different electrical potentials (grounded, negative, positive) to create electric fields that control ion beam uniformity. By adjusting these electrical parameters, the system can compensate for some degradation, extending the usable life of the grid assembly while maintaining acceptable yield.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If larger wafers are etched, then production capacity increases, but more unwanted material is etched away and sputtered on the grid assembly causing increased warping

Engineering Contradiction:

Improvewafer processing capacityVSAvoidmaterial deposition on grid

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The thicker first grid member acts as a structural counterweight that compensates for the warping forces generated by material deposition. This enhanced structural mass provides resistance against the mechanical stress from sputtered material, allowing larger wafers to be processed without accelerating grid assembly degradation.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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 solution maintains desirable ion beam uniformity and etch stability while reducing costs by extending the life of the grid assembly and improving fabrication yield, allowing for efficient reuse of grid members across varying etching requirements.

Implementation Method 1

the first grid member may be electrically grounded, the second grid member may be electrically negative relative to the first grid member, and the third grid member may be electrically positive relative to the first grid member

Methodology Applied

Scientific EffectElectrical field: Electric Field

Implementation Method 2

The ion beam may etch away unprotected/unwanted material from the wafer for forming particular device structures. A substantial amount of the unwanted material that is etched away from the wafer as well as the surrounding chamber wall areas exposed to the broad ion beam may sputter and adhere to the grid assembly

Methodology Applied

Scientific EffectSputtering: Sputtering

Data Source

PatentUS8703001B1Grid assemblies for use in ion beam etching systems and methods of utilizing the grid assemblies

Publication Date: 2014.04.22 PLASMA THERM NES LLC

AI summary

A grid assembly for use in an etching system for etching at least a wafer. The grid assembly may include a first grid member, a second grid member, and a third grid member. When the grid assembly is used in etching the wafer, the first grid member may be electrically grounded, the second grid member may be electrically negative relative to the first grid member, and the third grid member may be electrically positive relative to the first grid member. The second grid member may be disposed between the first grid member and the third grid member. The first grid member may be thicker than at least one of the second grid member and the third grid member.