Laser Annealing Semiconductor Substrates for Surface Cleanliness

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Solution Overview

Problem

Current semiconductor manufacturing processes face challenges in removing contaminants and defects from substrate surfaces without causing material diffusion, especially as device sizes shrink, leading to reduced process yields and performance issues.

Innovation Solution

The method involves selectively annealing a semiconductor substrate with a laser beam in the presence of hydrogen gas, which can be moved continuously or in a stepwise fashion, to heal defects and remove contaminants without significant material diffusion, followed by depositing a layer on the annealed substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high temperature hydrogen bake is used to remove contaminants and defects, then surface cleanliness is improved, but material diffusion between structures increases

Engineering Contradiction:

Improvesurface cleanlinessVSAvoidmaterial diffusion

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the fundamental parameter from thermal energy (high temperature bake) to optical energy (laser beam) to achieve surface cleaning. The laser beam provides localized heating and chemical reactions at the surface without bulk heating, thus removing contaminants while preventing thermal diffusion of materials in the substrate.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal field (heat-based hydrogen bake) with an optical field (laser beam) to achieve the same contaminant removal function. This substitution allows precise spatial and temporal control of energy delivery, enabling surface treatment without the unwanted thermal diffusion effects that plague conventional high-temperature processing.

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

This approach effectively removes contaminants and defects while limiting material diffusion, similar to high-temperature hydrogen baking but without the thermal budget issues, thereby improving semiconductor device performance and yield.

Implementation Method 1

selectively annealing a portion of the substrate with a laser beam

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

selectively annealing a portion of the substrate having at least one of a defect or a contaminant disposed on or near a surface of the substrate with a laser beam

Methodology Applied

Scientific EffectAnnealing: Annealing

Implementation Method 3

selectively annealing a portion of the substrate with a laser beam in the presence of a process gas comprising hydrogen

Methodology Applied

Scientific EffectChemical reaction with hydrogen: Reduction

Data Source

PatentUS7838431B2Method for surface treatment of semiconductor substrates

Publication Date: 2010.11.23 APPLIED MATERIALS INC

AI summary

Methods and apparatus for processing a substrate are provided herein. In some embodiments, a method of processing a substrate may include providing a substrate having at least one of a defect or a contaminant disposed on or near a surface of the substrate; and selectively annealing a portion of the substrate with a laser beam in the presence of a process gas comprising hydrogen. The laser beam may be moved over the substrate or continuously, or in a stepwise fashion. The laser beam may be applied in a continuous wave or pulsed mode. The process gas may further comprise an inert gas, such as, at least one of helium, argon, or nitrogen. A layer of material may be subsequently deposited atop the annealed substrate.