Dynamic Purging Recipe Selection for Semiconductor Film Formation
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Solution Overview
Problem
The existing film forming process in semiconductor device fabrication, specifically the purging process after forming silicon nitride films, is inefficient due to a fixed purging recipe that does not account for varying film thickness and particle production, leading to prolonged downtime and increased processing costs.
Innovation Solution
A method that automatically selects a purging recipe based on the cumulative thickness of films formed during the film forming process, using different temperature profiles and purging times to optimize the purging process, thereby reducing particle production and downtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed purging recipe is used for all film forming cycles, then the purging process can remove deposited films effectively, but the downtime increases and throughput decreases
Solution Approach 1:
The patent implements dynamic purging recipe selection by automatically adjusting purging parameters (temperature, time, gas flow rate) based on real-time detection of particle concentration and film thickness. The control unit modifies the purging process dynamically rather than using a fixed recipe, allowing optimization between particle removal effectiveness and processing time to maximize throughput.
Solution Approach 2:
The system changes multiple purging parameters simultaneously including temperature profiles, purging gas flow rates, and process duration based on detected conditions. When particle concentration or film thickness exceeds thresholds, the control unit selects from multiple pre-programmed purging recipes with different parameter combinations to achieve effective particle removal while minimizing downtime.
2Object-generated harmful factors
If a strong purging process is applied to remove thick deposited films, then particle production is suppressed, but the purging time increases significantly
Solution Approach 1:
The system continuously monitors particle concentration in the reaction vessel and film thickness on the wafer holder using sensors. This feedback information is fed to the control unit which automatically adjusts the purging recipe selection and parameters in real-time, applying strong purging only when particle levels or film thickness warrant it, thereby minimizing unnecessary purging time while suppressing particle production.
Solution Approach 2:
Instead of always applying maximum purging strength, the system applies partial purging action when conditions permit, using weaker purging recipes for thin films or low particle conditions. The control unit scales the purging intensity to match the actual need, avoiding excessive purging time while still suppressing particle production when necessary.
3Object-generated harmful factors
If the purging process is extended to ensure complete removal of deposited films, then gas production is suppressed, but the processing cost increases
Solution Approach 1:
The control unit uses real-time feedback from particle sensors and film thickness measurements to determine when sufficient purging has been achieved. The system extends purging duration only when sensor data indicates ongoing particle generation or excessive film buildup, automatically terminating the purging process when particle levels and film thickness are within acceptable ranges, thereby suppressing gas production without unnecessary time extension.
4Ease of operation
If a fixed purging recipe is used regardless of film thickness, then the process is simple to operate, but the purging efficiency decreases
Solution Approach 1:
The system performs self-adjustment of purging parameters based on automatic detection of film thickness and particle concentration. The control unit autonomously selects the appropriate purging recipe and modifies parameters without operator intervention, maintaining ease of operation while achieving high purging efficiency through adaptive response to actual process conditions.
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 reduces unnecessary purging time, minimizes particle production, and enhances the throughput of the film forming system by tailoring the purging process to the specific conditions of each film forming cycle, thus optimizing the film forming process efficiency.
Implementation Method 1
a purging gas, such as nitrogen gas (N2) is supplied into the reaction vessel... to remove surface layers of the films adhering to the inner surface of the reaction vessel positively
Implementation Method 2
the reaction vessel is cooled rapidly, is evacuated and heated to remove surface layers of the films adhering to the inner surface of the reaction vessel positively by the purging process
Implementation Method 3
the reaction vessel is cooled rapidly
Implementation Method 4
the reaction vessel is cooled rapidly, is evacuated and heated
Implementation Method 5
the reaction vessel is cooled rapidly, is evacuated and heated to remove surface layers of the films
Implementation Method 6
the reaction vessel is cooled rapidly, is evacuated and heated to remove surface layers of the films adhering to the inner surface of the reaction vessel
Data Source
AI summary
After silicon nitride films have been formed on wafers by a film forming process in a reaction vessel, the reaction vessel is processed by a purging process specified by a purging recipe and compatible with the film forming process to suppress production of gases and particles by removing surface parts of films deposited on the inside surface of the reaction vessel and causative of production of gases and particles.A wafer boat 25 holding a plurality of wafers W is loaded into a reaction vessel 2, and the wafers W are processed by a film forming process specified by a film forming recipe 1 specifying, for example, Si2Cl2 gas and NH3 gas as film forming gases. Subsequently, a purging recipe 1 specifying a purging process compatible to the film forming process is selected automatically, and the reaction vessel 2 is processed by the purging process specified by the purging recipe 1. A purging recipe is selected automatically from a plurality of purging recipes specifying purging processes respectively compatible with film forming processes. Unnecessary extension of purging time is suppressed and the reaction vessel 2 can be processed by an appropriate purging process compatible with the film forming process.