Scheduling Processing Tools with Tool-Specific Process Models
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Solution Overview
Problem
Conventional semiconductor manufacturing systems rely on a single process model to control feature dimensions across multiple processing tools, which is insufficient when there is a lack of one-to-one correspondence between tools, leading to variations in feature sizes due to different etch biases and photolithography stepper settings, resulting in inconsistent final inspection critical dimensions.
Innovation Solution
A method for scheduling processing tools involves selecting a combination of tools, determining a target output parameter, and adjusting input parameters for the photolithography tool based on this combination to ensure accurate feature control, using metrology tools to measure development and final inspection critical dimensions and adjusting process models accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single process model is used to control features across multiple processing tools, then device complexity is reduced, but manufacturing precision deteriorates due to variations in etch biases and photolithography settings
Solution Approach 1:
The patent divides the single process model into multiple tool-specific process models, each tailored to account for the unique characteristics and biases of individual processing tools. This segmentation allows each model to precisely capture tool-specific variations in etch bias and photolithography settings, thereby improving manufacturing precision without requiring a single overly complex unified model.
Solution Approach 2:
The patent applies local quality by creating customized process models for each processing tool based on its specific characteristics. Each tool receives a process model that is locally optimized for its particular etch bias, processing conditions, and performance characteristics, rather than using a generic single model that must accommodate all tools uniformly.
2Productivity
If multiple photolithography steppers are used to supply wafers to multiple etching tools, then productivity increases, but manufacturing precision deteriorates due to lack of one-to-one correspondence between tools
Solution Approach 1:
The patent changes the parameter of process control by implementing tool-specific process models that adjust for variations in etch bias and photolithography settings. Each photolithography stepper and etching tool combination is characterized with its own parameters, allowing the system to maintain precise control over final inspection critical dimensions while supporting multiple tools operating in parallel to increase productivity.
3Manufacturing precision
If feedback control is applied to processing tools, then manufacturing precision improves, but device complexity increases due to additional control systems
Solution Approach 1:
The patent implements feedback control through tool-specific process models that use measured data from each processing tool to adjust and refine control parameters. The system continuously monitors processing outcomes and feeds this information back to update the process models, enabling automatic compensation for tool variations and drift without requiring complex manual intervention or overly sophisticated control systems.
Data Source
AI summary
The present invention provides a method and apparatus for scheduling a plurality of processing tools. The method comprises providing a first processing tool and a plurality of second processing tools, selecting one of the plurality of second processing tools, and determining a target output parameter of a combination of processing tools comprising said first processing tool and said selected one of the plurality of second processing tools. The method also includes determining at least one input parameter of a process model for controlling the first processing tool based upon the target output parameter of the combination of processing tools.