Wafer Cleaning Laser Beam Profile for Etch Uniformity

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Solution Overview

Problem

Conventional wafer cleaning equipment using batch processing faces issues such as flowability defects, drying defects, and non-uniform dispersion, while single-wafer processing equipment often experiences varying etch rates across the wafer.

Innovation Solution

The proposed wafer cleaning equipment employs a housing with a laser module that outputs a laser beam with varying intensities between the center and edge regions, ensuring uniform heating of the wafer surface through a transparent window, and a spinner system that rotates the wafer to maintain consistent temperature distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If batch equipment is used to process multiple wafers simultaneously, then productivity is improved, but manufacturing precision deteriorates due to flowability defects, drying defects, and non-uniform dispersion

Engineering Contradiction:

Improvenumber of wafers processed simultaneouslyVSAvoiduniformity of etching across wafers

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The batch processing system is segmented into individual single-wafer processing stations arranged in series. Each wafer is processed separately through the same cleaning and etching sequence, eliminating inter-wafer interference while maintaining high throughput through continuous circulation of the processing chamber.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system employs periodic action by repeatedly cycling wafers through the processing chamber multiple times. Each pass provides controlled exposure to the laser beam and chemical solution, with the cumulative effect achieving uniform etching across all wafers while maintaining high productivity through continuous operation.

Inventive Principle:

Principle #19Periodic action

2Manufacturing precision

If single-wafer processing equipment is used to improve manufacturing precision, then etch rate uniformity improves, but productivity deteriorates due to sequential processing of each wafer

Engineering Contradiction:

Improveetch rate uniformity across waferVSAvoidprocessing throughput

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The processing chamber is designed with multi-functionality to serve both single-wafer precision processing and high-productivity operations. The same chamber performs cleaning, etching, and drying functions across multiple processing cycles, eliminating the need for separate equipment while maintaining precision through controlled single-wafer exposure.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system maintains continuity of useful action by continuously circulating wafers through the processing chamber without idle time. The laser beam and chemical solution are continuously applied during each pass, and wafers are immediately transferred to the next processing stage, eliminating downtime and maximizing productivity while preserving precision.

Inventive Principle:

Principle #20Continuity of useful action

3Device complexity

If uniform laser beam intensity is applied across the wafer surface, then manufacturing simplicity is improved, but manufacturing precision deteriorates due to edge region insufficient heating

Engineering Contradiction:

Improvelaser beam profile controlVSAvoidtemperature uniformity across wafer surface

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The laser beam profile is modified to provide local quality by increasing intensity at the edge regions of the wafer compared to the center. This non-uniform distribution compensates for the natural cooling effect at the edges during rotation, ensuring uniform temperature distribution across the entire wafer surface without requiring complex additional heating systems.

Inventive Principle:

Principle #3Local quality

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 ensures uniform etching across the wafer by adjusting the laser beam profile to heat the edge region more intensely than the center, thereby stabilizing the etch rate and preventing unintended cooling, thus enhancing the overall cleaning efficiency.

Implementation Method 1

a laser module that outputs a laser beam having a profile of the laser beam includes a first region having a first intensity and a second region having a second intensity greater than the first intensity, the laser beam being output into the hollow region

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

a transparent window that covers an upper part of the hollow region and transmits the laser beam to be incident on an entirety of a lower surface of the wafer

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentUS11605545B2Wafer cleaning equipment

Publication Date: 2023.03.14 SAMSUNG ELECTRONICS CO LTD

AI summary

A wafer cleaning equipment includes a housing to be positioned adjacent to a wafer, a hollow region in the housing, a laser module that outputs a laser beam having a profile of the laser beam includes a first region having a first intensity and a second region having a second intensity greater than the first intensity, the laser beam being output into the hollow region, and a transparent window that covers an upper part of the hollow region and transmits the laser beam to be incident on an entirety of a lower surface of the wafer.