End Effector Shock Sensing for Wafer Bump Detection

Solution Overview

Problem

Existing robotic arm systems in manufacturing, particularly in semiconductor wafer handling, face challenges in detecting minor misalignments and bumps that can cause micro fractures in wafers, which are difficult to detect and result in yield problems.

Innovation Solution

A contact shock transients sensing unit coupled to the robot arm, configured to detect contact shock transients and generate signals corresponding to these events, is used in conjunction with a control unit to measure signal amounts and determine if they exceed predetermined thresholds, triggering appropriate operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If expensive cameras and delicate pressure sensors are used to detect bumps and misalignments, then measurement precision is improved, but device complexity and cost increase significantly

Engineering Contradiction:

Improvebump detection precisionVSAvoiddetection system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces expensive cameras and delicate pressure sensors with accelerometers that detect mechanical vibrations and shocks. The accelerometers sense contact shocks through mechanical vibrations generated during wafer handling, converting physical shock events into electrical signals for processing. This substitution maintains detection capability while dramatically reducing system complexity and cost.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs accelerometers as inexpensive, robust sensing elements that can be easily replaced if needed. These sensors are far cheaper than cameras or pressure sensors, and their solid-state construction makes them durable and suitable for industrial environments. The low cost allows deployment across multiple robot arms without prohibitive expense.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Measurement precision

If expensive cameras and delicate pressure sensors are used to detect bumps and misalignments, then measurement precision is improved, but manufacturing cost increases and becomes prohibitive

Engineering Contradiction:

Improvebump detection precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive cameras and delicate pressure sensors with accelerometers that detect mechanical vibrations and shocks. The accelerometers sense contact shocks through mechanical vibrations generated during wafer handling, converting physical shock events into electrical signals for processing. This substitution maintains detection capability while dramatically reducing system complexity and cost.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs accelerometers as inexpensive, robust sensing elements that can be easily replaced if needed. These sensors are far cheaper than cameras or pressure sensors, and their solid-state construction makes them durable and suitable for industrial environments. The low cost allows deployment across multiple robot arms without prohibitive expense.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If visual inspection methods are used to detect wafer damage, then detection capability is improved, but the ability to inspect certain areas is limited and detection timing is delayed

Engineering Contradiction:

Improvewafer damage detection capabilityVSAvoiddetection coverage and timing information

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent detects contact shocks at the moment they occur during wafer handling operations, before the wafer is processed or damaged areas become visible. By monitoring accelerometers on robot arms in real-time, the system identifies bumps and misalignments immediately when they happen, enabling preventive action before damage propagates or becomes undetectable.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses accelerometers as intermediary sensors mounted on robot arms to detect contact shocks indirectly. Instead of directly inspecting the wafer or cassette interior, the accelerometers sense vibrations and shocks transmitted through the robot arm during handling operations. This intermediary approach provides detection coverage in areas that are otherwise inaccessible to visual inspection.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 detects abnormal wafer contact during manufacturing, assists in maintaining end effector alignment, and prevents damage to wafers by identifying and addressing minor misalignments and bumps in real-time.

Implementation Method 1

a contact shock transients sensing unit coupled to the robot arm and configured to detect contact shock transients on the robot arm, and generate a signal corresponding to contact shock transients

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS12343880B2End effector bump detector

Publication Date: 2025.07.01 TEXAS INSTRUMENTS INC

AI summary

A system and method is described for detecting abnormal contacts and misalignment of end effector of a robot arm during robotic arm operation. A contact shock transients sensing unit detects signals on the robot arm and generates alarms, identifies the location of the contact shock transients in the robot arm operation, and controls robot arm operation to prevent further damage to the robot arm and articles handled by the robot arm.