Wafer Position Calculation Using Laser Light Source Assembly

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Solution Overview

Problem

Current semiconductor processing methods for determining the offset position of a wafer within a processing chamber are time-consuming and inefficient, requiring multiple heating and cooling cycles to establish the correct wafer loading point.

Innovation Solution

An apparatus and method utilizing a laser light source assembly mounted outside the reaction chamber, which measures the position of the susceptor sidewall and a test wafer to calculate the relative offset, allowing for precise positioning of the wafer center point without the need for extensive heating and cooling cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional manual methods are used to determine wafer position by heating the chamber and performing load/unload steps, then the wafer center position can be found, but the process takes excessive time

Engineering Contradiction:

Improvewafer center position accuracyVSAvoidtime to determine wafer loading point

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the manual mechanical method of determining wafer position (physical load/unload steps with operator observation) with an optical measurement system. A laser light source projects through a window in the reaction chamber to directly measure the position of the susceptor sidewall and wafer, eliminating the need for time-consuming manual loading/unloading cycles while maintaining measurement accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary optical measurement system (laser light source and window) that enables position measurement without requiring physical access to the wafer through loading/unloading. The laser beam acts as an intermediary that can penetrate through the chamber window to measure positions internally, thereby solving the time loss problem while preserving measurement capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If the chamber is heated to processing temperature to measure wafer position, then accurate position under process conditions is obtained, but the measurement process becomes time-consuming

Engineering Contradiction:

Improvewafer position accuracy under process conditionsVSAvoidtime for temperature adjustment and measurement

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables position measurements to be performed at any stage including during processing temperature, by having the optical measurement system (laser and window) already in place and operational. This eliminates the need to cool down the chamber for measurement purposes, as the system can accurately measure wafer position under actual process conditions without requiring preliminary temperature adjustments.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent changes the measurement parameter from requiring ambient or cooled chamber conditions to allowing measurements at processing temperatures. The optical measurement system is designed to function across a range of temperatures, enabling position determination under actual process conditions (high temperature) rather than requiring parameter changes to cooler temperatures for measurement.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If multiple load and unload steps are performed to determine wafer position, then the proper loading point is identified, but the procedure complexity increases

Engineering Contradiction:

Improvewafer loading point determinationVSAvoidnumber of steps in positioning procedure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the complex multi-step mechanical procedure (repeated loading and unloading with manual observation) with a simple optical measurement system. The laser light source directly measures susceptor and wafer positions through the chamber window, reducing the positioning determination from multiple iterative steps to a single direct measurement operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables faster and more accurate determination of the wafer center position, reducing processing time and improving the efficiency of semiconductor fabrication by allowing wafer positioning at processing temperatures without the need for extensive thermal conditioning.

Implementation Method 1

at least one light source positioned outside of the reaction space, at least one window in the reaction chamber, and wherein the at least one light source is directed through the at least one window to contact the sidewall

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 2

The at least one light source may be a laser

Methodology Applied

Scientific EffectLaser: Laser

Data Source

PatentUS9117866B2Apparatus and method for calculating a wafer position in a processing chamber under process conditions

Publication Date: 2015.08.25 ASM IP HLDG BV

AI summary

An apparatus for processing a wafer including a reaction chamber having a reaction space for processing the wafer, a susceptor positioned within the reaction chamber and having a sidewall, at least one light source positioned outside of the reaction space, at least one window in the reaction chamber, and wherein the at least one light source is directed through the at least one window to contact the sidewall.