Wafer Processing Tool Warpage Detection Sensor

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Solution Overview

Problem

The increasing complexity of semiconductor IC manufacturing due to scaling down processes leads to significant wafer warpage, which affects the reliability and yield of semiconductor devices, as stresses between material layers cause cracks and poor reliability.

Innovation Solution

A wafer processing tool equipped with a sensor set that radially extends from the center to the edge of the wafer, allowing for efficient scanning and monitoring of the entire surface, enabling the detection and measurement of warpage by rotating the wafer holder relative to the sensor set, thereby allowing for adjustments in process parameters and materials to improve product quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If wafer scaling down process is implemented to increase functional density, then production efficiency is improved and costs are lowered, but wafer warpage increases causing cracks and poor reliability

Engineering Contradiction:

Improveproduction efficiencyVSAvoidwafer reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs preliminary detection of wafer warpage using optical sensors before the warpage causes critical damage. By detecting warpage early in the processing sequence, the system can take preventive actions to maintain wafer integrity while continuing the scaling down process for improved productivity.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where optical sensors continuously monitor wafer warpage during processing, and this information is fed back to control the processing parameters. This allows dynamic adjustment to maintain reliability while preserving the benefits of scaling down for production efficiency.

Inventive Principle:

Principle #23Feedback

2Device complexity

If traditional measurement methods are used for wafer warpage, then device complexity is reduced, but measurement precision and detection capability are insufficient

Engineering Contradiction:

Improvemeasurement system complexityVSAvoidwafer warpage detection precision

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces complex mechanical contact-based measurement systems with optical sensing systems. This substitution maintains relatively simple device architecture while dramatically improving measurement precision, as optical sensors can detect subtle warpage variations without physical contact that might damage the wafer.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical measurement system is designed to perform multiple functions: detecting warpage, monitoring wafer position, and evaluating surface topology. This multi-functionality reduces the need for separate specialized devices, maintaining device complexity at acceptable levels while achieving high measurement precision through a single versatile system.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If comprehensive wafer surface scanning is performed to detect warpage, then measurement precision is improved, but loss of time increases due to scanning the entire surface

Engineering Contradiction:

Improvewarpage measurement accuracyVSAvoiddetection time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements continuous warpage detection during the wafer processing operation itself, rather than performing separate discrete measurement steps. The optical sensors operate continuously as the wafer moves through the processing chamber, maintaining measurement precision while eliminating idle detection time that would otherwise be lost between processing steps.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The measurement system is designed to be dynamic, adapting its scanning pattern and intensity based on real-time conditions. The system can focus measurement resources on areas showing signs of warpage while reducing scanning in stable regions, thereby maintaining high measurement precision while minimizing the overall detection time across the entire wafer surface.

Inventive Principle:

Principle #15Dynamics

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

This solution effectively measures and monitors wafer warpage, enhancing process yield and product reliability by allowing for real-time adjustments in manufacturing processes, thus addressing the challenges posed by scaling down in semiconductor IC production.

Implementation Method 1

an optical sensor to scan the entire top surface or back surface of the wafer to obtain a topography of the entire top surface or back surface of the wafer

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS10804124B2Wafer processing tool capable of detecting wafer warpage and method for detecting wafer warpage

Publication Date: 2020.10.13 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A wafer processing tool is capable of detecting wafer warpage. The wafer processing tool includes a wafer holder on which a wafer is held and at least one sensor set. The at least one sensor set is disposed above the wafer or under the wafer, and a projection of each of the at least one sensor set on the wafer radially extending from a center of the wafer to an edge of the wafer. The at least one sensor set is configured to scan an entire surface of the wafer so as to measure warpage of the wafer while the wafer holder and the at least one sensor set are rotatable relative to each other.