Dynamic RF Power Compensation for Plasma ALD Film Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In plasma-assisted atomic layer deposition (PAALD) processes, film properties such as thickness and etch rates tend to drift over time within a batch due to changing chamber impedance caused by material accumulation, leading to non-uniform film deposition and potential device performance degradation.
Innovation Solution
The method involves calibrating RF power supply based on chamber accumulation by determining a relationship between film thickness and RF power, adjusting the RF power dynamically during the batch to maintain consistent film properties, and using statistical analysis to derive an optimal generator setpoint for stable film deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a batch of substrates is processed in PAALD, then productivity is improved, but film thickness uniformity deteriorates due to chamber impedance changes
Solution Approach 1:
The patent applies dynamics by making the RF power adjustable during the batch process. The system transitions from a static RF power setting to a dynamic one where power levels are modified based on real-time chamber impedance measurements, allowing the process to adapt to changing conditions and maintain film uniformity throughout the batch
Solution Approach 2:
The patent implements feedback control by measuring chamber impedance during the batch process and using this information to adjust RF power levels. The system continuously monitors impedance changes and feeds this information back to the RF power control, enabling automatic compensation for drift and maintaining consistent film deposition
2Productivity
If RF power is increased to maintain film deposition rate, then productivity is improved, but film thickness control precision deteriorates due to chamber accumulation
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the RF power parameter based on chamber impedance measurements. Instead of maintaining a constant high power for productivity, the system modifies the power parameter in response to accumulating material in the chamber, thereby maintaining both deposition rate and thickness control precision through adaptive parameter adjustment
3Device complexity
If constant RF power is used throughout the batch, then device complexity is reduced, but film property consistency deteriorates
Solution Approach 1:
The patent applies self-service by enabling the system to automatically monitor its own chamber impedance and adjust RF power without external intervention. The chamber essentially serves itself by providing impedance feedback that triggers automatic power adjustments, eliminating the need for complex external control systems while maintaining film consistency
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 results in more stable film thickness and etch rates over the batch, reducing within-wafer and within-die variations, thereby improving device performance and yield by maintaining consistent film properties across substrates.
Implementation Method 1
supplying an RF power to generate a plasma and exposing the substrate to the plasma to drive a reaction that deposits the film on the substrate
Data Source
AI summary
Methods for depositing film on substrates are provided. In these embodiments, the substrates are processed in batches. Due to changing conditions within a reaction chamber as additional substrates in the batch are processed, various film properties may trend over the course of a batch. The methods herein can be used to address the trending of film properties over the course of a batch. More specifically, film property trending is minimized by changing the amount of RF power used to process substrates over the course of the batch. Such methods are sometimes referred to as RF compensation methods.