Lever Actuated Substrate Sensors for CMP Load Cup Positioning

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Solution Overview

Problem

In chemical mechanical polishing systems, existing load cups often damage substrates due to misalignment and contact with the feature side, and generate particulates that cause non-uniform polishing and device defects, highlighting the need for improved substrate sensing mechanisms to minimize contact and ensure precise positioning.

Innovation Solution

A load cup assembly with lever actuated substrate sensors and counterweights that detect the presence and correct positioning of substrates without contacting the feature side, using sensors and micro switches connected to a controller to prevent damage and fluid migration onto the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the load cup uses close tolerance positioning between the load cup and polishing head, then substrate transfer reliability is improved, but the risk of substrate damage from misalignment increases

Engineering Contradiction:

Improvesubstrate transfer reliabilityVSAvoidsubstrate damage from misalignment

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sensing mechanism detects substrate presence and positioning in the load cup before the polishing head engagement, allowing the system to verify correct positioning in advance and prevent damage by aborting or adjusting the transfer operation if misalignment is detected

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sensing mechanism provides real-time feedback on substrate presence and positioning status to the control system, enabling closed-loop control of the substrate transfer process and dynamic adjustment to prevent misalignment damage

Inventive Principle:

Principle #23Feedback

2Stability of the object's composition

If the load cup supports the substrate with direct contact surfaces, then substrate positioning stability is improved, but substrate scratching and particulate generation increase

Engineering Contradiction:

Improvesubstrate positioning stabilityVSAvoidsubstrate scratching and particulate generation

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The invention replaces direct mechanical contact between the load cup and substrate feature side with a non-contact sensing system using optical or capacitive sensors that detect substrate presence and position through electromagnetic fields or light, eliminating mechanical scratching and particulate generation while maintaining positioning stability through precise detection and control

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If the load cup allows substrate contact during transfer, then transfer simplicity is improved, but fluid migration onto the substrate feature side increases

Engineering Contradiction:

Improvesubstrate transfer simplicityVSAvoidfluid migration onto substrate

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The sensing mechanism provides real-time feedback on substrate positioning relative to the load cup, enabling the control system to precisely control the timing and extent of substrate contact and fluid exposure, allowing simple transfer operations while preventing harmful fluid migration through automated positioning control

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 provides reliable substrate detection and positioning, reducing damage and fluid contact with the feature side, thereby enhancing the precision and efficiency of substrate transfer in chemical mechanical polishing systems.

Implementation Method 1

a plurality of lever actuated substrate sensors disposed on the pedestal member and equally spaced about the peripheral region of the pedestal member

Methodology Applied

Scientific EffectMechanical contact actuation: Mechanical Force

Data Source

PatentUS8734202B2Load cup substrate sensing

Publication Date: 2014.05.27 APPLIED MATERIALS INC

AI summary

Embodiments of the present invention generally provide a load cup used in the transfer of substrates in a chemical mechanical polishing system. The load cup includes an improved substrate edge sensing mechanism to ensure a substrate is present and correctly positioned in the load cup for transfer to a polishing head. In one embodiment, a lever actuated edge sensing mechanism is provided. In one embodiment, the edge of a substrate contacts a lever, which contacts a sensor to detect that the substrate is present and correctly positioned for exchange with a polishing head. Embodiments of the present invention provide reliable detection, while reducing contact with the feature side of the substrate during substrate transfer.