Sensor Wafer Vibration and Displacement Measurement

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Solution Overview

Problem

In semiconductor manufacturing, lift pin vibrations cause undesirable substrate displacement due to misalignment and non-coplanar lift pins, leading to processing uniformity issues, as existing sensors cannot accurately correlate lift pin vibrations with substrate movement.

Innovation Solution

A sensor wafer with integrated vibration and position sensors, coupled with a computing system that includes a placement controller, measures and characterizes lift pin-induced vibrations and displacements, determining when vibrations exceed a threshold to cause wafer movement, allowing for real-time adjustments and maintaining chamber performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If vibration sensors are used to measure vibrations from the lift pins, then vibration measurement capability is improved, but the ability to correlate vibration to wafer displacement remains insufficient due to lack of feedback mechanism

Engineering Contradiction:

Improvevibration measurement capabilityVSAvoidcorrelation information between vibration and displacement

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent implements a feedback mechanism by using capacitive sensors to detect wafer displacement and correlating this data with vibration sensor measurements. The system continuously monitors both vibration levels and actual displacement, creating a closed-loop feedback system that enables real-time correlation between lift pin vibrations and wafer position changes, thereby resolving the information loss problem

Inventive Principle:

Principle #23Feedback

2Ease of operation

If lift pins are used to raise and lower the substrate, then substrate placement capability is improved, but substrate displacement and misalignment occur due to lift pin vibrations

Engineering Contradiction:

Improvesubstrate placement capabilityVSAvoidsubstrate alignment accuracy

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The system uses capacitive sensors to continuously monitor wafer position during lift pin operation and provides real-time feedback on displacement. This feedback enables the detection of misalignment caused by vibrations, allowing for corrective actions to maintain manufacturing precision while preserving the ease of substrate placement

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces purely mechanical alignment methods with a sensor-based detection system. Capacitive sensors and vibration sensors substitute for mechanical alignment mechanisms, enabling non-contact measurement of wafer position and vibration levels, thereby improving alignment accuracy without compromising the mechanical lift pin placement mechanism

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If multiple lift pins are used to support the substrate, then substrate support capability is improved, but non-coplanar lift pins cause tilting and displacement

Engineering Contradiction:

Improvesubstrate support capabilityVSAvoidsubstrate flatness and centering

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback system using capacitive sensors positioned at multiple locations to detect differential displacement between lift pins. By monitoring the relative positions of multiple support points, the system can detect tilting and non-coplanarity conditions, providing feedback that enables correction of alignment issues while maintaining reliable multi-point substrate support

Inventive Principle:

Principle #23Feedback

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 effectively detects and mitigates lift pin-induced wafer displacement, ensuring accurate substrate placement and processing uniformity by providing real-time feedback on vibration-induced movement, thereby reducing the risk of misalignment and maintaining chamber performance.

Implementation Method 1

measuring the vibration of the sensor wafer with the vibration sensor

Methodology Applied

Scientific EffectVibration: Vibration

Implementation Method 2

a vibration sensor embedded within the substrate

Methodology Applied

Scientific EffectPiezoelectric Effect: Piezoelectric Effect

Implementation Method 3

the sensor regions comprise self-referencing capacitive sensors

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11342210B2Method and apparatus for measuring wafer movement and placement using vibration data

Publication Date: 2022.05.24 APPLIED MATERIALS INC

AI summary

Embodiments disclose herein include a sensor wafer. In an embodiment, the sensor wafer comprises a substrate, wherein the substrate comprises a first surface, a second surface opposite the first surface, and an edge surface between the first surface and the second surface. In an embodiment, the sensor wafer further comprises a plurality of sensor regions formed along the first surface, wherein the sensor regions comprise self-referencing capacitive sensors. In an embodiment, the sensor wafer further comprises a vibration sensor embedded within the substrate.