Wafer Laser Annealing with Reflectivity-Based Power Control

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Solution Overview

Problem

As semiconductor devices are fabricated with increasingly smaller features, variations in reflectivity across a wafer lead to non-uniform temperature distribution during laser annealing, affecting the quality and integration of electronic components.

Innovation Solution

A wafer annealing system that measures local reflectivity across the wafer and adjusts laser shot power based on these measurements to achieve uniform temperature distribution, using a controller to determine and adjust the power and duration of laser shots for each area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If laser annealing is performed on a wafer with varying reflectivity across different areas, then the annealing process can be completed, but non-uniform temperature distribution occurs affecting device quality

Engineering Contradiction:

Improvetemperature uniformityVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent applies local quality by measuring the reflectivity of different areas on the wafer surface and adjusting the laser power specifically for each area based on its reflectivity characteristics. This ensures that each local region receives the appropriate energy dosage to achieve uniform temperature distribution across the entire wafer, directly resolving the temperature uniformity issue caused by varying reflectivity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements feedback control by measuring the reflectivity of each area before annealing and using this measurement to dynamically adjust the laser power settings. This closed-loop approach ensures that areas with higher reflectivity receive higher power while areas with lower reflectivity receive lower power, maintaining temperature uniformity throughout the annealing process.

Inventive Principle:

Principle #23Feedback

2Manufacturing precision

If minimum feature size is reduced to improve integration density, then more components can be integrated, but additional process problems arise that affect manufacturing precision

Engineering Contradiction:

Improvefeature size controlVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent addresses feature size control by dynamically adjusting the laser power parameter based on the measured reflectivity of each area. This parameter change approach allows precise control of the annealing process even at reduced minimum feature sizes, compensating for variations in material properties and ensuring consistent feature dimensions despite the increased process complexity associated with smaller features.

Inventive Principle:

Principle #35Parameter changes

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 ensures that all areas of the wafer reach a desired final anneal temperature range, improving the properties and uniformity of semiconductor devices by restoring crystalline structure and enhancing film quality.

Implementation Method 1

performing a first laser shot on the first anneal region, wherein a power of the first laser shot is set in accordance with the first reflectivity

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

measuring a first temperature of the first anneal region; and performing a second laser shot on a second anneal region

Methodology Applied

Scientific EffectOptical to thermal energy conversion: Absorption (EM radiation)

Implementation Method 3

measuring a first temperature of the first anneal region

Methodology Applied

Scientific EffectThermal radiation detection: Thermal Radiation

Data Source

PatentUS20250357142A1Systems, Methods, and Semiconductor Devices

Publication Date: 2025.11.20 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A manufacturing tool includes a probe laser and a pyrometer under control of a controller. The manufacturing tool may be configured to impinge radiation from the laser upon a wafer and to detected reflected light from the wafer by the pyrometer to determine a first reflectivity of a first anneal region on the wafer, and to determine a second reflectivity of a second anneal region on the wafer. The tool may be further configured to perform a first laser shot on the first anneal region, measure a first temperature of the first anneal region, and perform a second laser shot on a second anneal region. A power of the first laser shot is set in accordance with the first reflectivity. A power of the second laser shot is set in accordance with the second reflectivity.