Electrostatic Element Trajectory Control for Ion Implantation

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Solution Overview

Problem

Conventional ion implantation systems suffer from particle contamination issues due to deposits on beam optics, leading to device failure, poor film quality, and stringent control requirements as device dimensions shrink, especially when using selective plasma etching processes.

Innovation Solution

A system and method involving an additional electrostatic element adjacent to the beam-line electrostatic element to shape a local electrostatic field, controlling the trajectory of contamination particles by modifying their velocity and direction, thereby preventing them from reaching the wafer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If beam-line components are operated for extended periods to maintain productivity, then production output increases, but particle contamination on the wafer increases due to deposit buildup and flaking

Engineering Contradiction:

Improveproduction outputVSAvoidparticle contamination

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by introducing a repulsive electrostatic field before particles can contaminate the wafer. The additional electrostatic element creates a controlled electric field that actively repels charged particles away from the wafer surface, preventing contamination before it occurs. This allows continuous operation without the need to shut down for cleaning, maintaining productivity while preventing the harmful effect of particle buildup.

Inventive Principle:

Principle #9Preliminary anti-action

2Object-affected harmful factors

If additional electrostatic elements are added to control particle trajectory, then particle contamination is reduced, but device complexity increases

Engineering Contradiction:

Improveparticle contaminationVSAvoidbeam-line component structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses an intermediary electrostatic field as a mediator between the beam-line components and the wafer. Instead of directly preventing particle generation or requiring complex mechanical barriers, the additional electrostatic element creates an intermediate force field that guides particles away from the wafer. This intermediary approach effectively reduces contamination while adding only one additional electrode and its power supply, rather than fundamentally redesigning the entire beam line.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If electrostatic field is used to repel particles from wafer, then particle trajectory is controlled, but energy consumption increases due to additional power source

Engineering Contradiction:

Improveparticle trajectory controlVSAvoidpower consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent applies partial action by using the additional electrostatic element only in the specific region where particle repulsion is needed, rather than applying electrostatic fields throughout the entire system. The additional electrode is positioned strategically near the wafer surface where contamination is most problematic, creating a localized repulsive field that controls particle trajectory only where necessary. This partial application minimizes energy consumption compared to system-wide electrostatic control.

Inventive Principle:

Principle #16Partial or excessive action

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

Effectively reduces particle contamination along the ion beam-line, preserving ion beam quality and reducing the need for maintenance, while maintaining precise control over particle trajectories.

Implementation Method 1

an additional electrostatic element is provided in proximity to the beam-line electrostatic element to shape a local electrostatic field in proximity to the beam-line electrostatic element

Methodology Applied

Scientific EffectElectrostatic field: Electric Field

Implementation Method 2

to create a field shape to prohibit or limit the transport of particle defects along an ion beam-line

Methodology Applied

Scientific EffectElectrostatic force: Lorentz Force

Implementation Method 3

One or more power sources are configured to supply a voltage to the beam-line electrostatic element to generate an electrostatic field to accelerate ions along the ion beam-line

Methodology Applied

Scientific EffectElectrostatic field: Electric Field

Data Source

PatentUS9721750B2Controlling contamination particle trajectory from a beam-line electrostatic element

Publication Date: 2017.08.01 VARIAN SEMICON EQUIP ASSC INC

AI summary

Provided herein are approaches for controlling particle trajectory from a beam-line electrostatic element. In an exemplary approach, a beam-line electrostatic element is disposed along a beam-line of an electrostatic filter (EF), and a voltage is supplied to the beam-line electrostatic element to generate an electrostatic field surrounding the beam-line electrostatic element, agitating a layer of contamination particles formed on the beam-line electrostatic element. A trajectory of a set of particles from the layer of contamination particles is then modified to direct the set of particles to a desired location within the EF. In one approach, the trajectory is controlled by providing an additional electrode adjacent the beam-line electrostatic element, and supplying a voltage to the additional electrode to control a local electrostatic field in proximity to the beam-line electrostatic element. In another approach, the trajectory is influenced by one or more geometric features of the beam-line electrostatic element.