Furnace Wafer Dispatch Control for Variation Reduction
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Solution Overview
Problem
The batch furnace process in semiconductor manufacturing introduces variations in electrical and physical properties among wafers due to the loading effect, causing inconsistent product characteristics.
Innovation Solution
A dispatch control method that calculates and orders wafers based on characteristic variation values, placing them in the furnace in descending order to compensate for pre-process variations, using advanced process control and manufacturing execution systems to optimize placement and reduce overall variation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wafers are placed in different locations in the furnace during batch processing, then productivity is improved, but characteristic variation among wafers increases due to loading effect
Solution Approach 1:
The patent applies local quality by assigning different placement locations within the furnace to different lots of wafers based on their specific characteristic variation values. Each location in the furnace has different thermal characteristics, and by matching wafers with specific characteristic profiles to appropriate locations, the system optimizes local conditions for each batch to minimize overall variation while maintaining batch processing productivity
Solution Approach 2:
The system changes the placement location parameter based on the characteristic variation values of different wafer lots. By calculating and comparing characteristic variation values, the dispatch system dynamically adjusts which lots are placed in which furnace locations, transforming a static placement approach into a dynamic, parameter-based allocation strategy that reduces characteristic variation
2Manufacturing precision
If characteristic variation values are calculated and used to order wafer lots, then manufacturing precision is improved, but device complexity increases due to additional calculation and control steps
Solution Approach 1:
The patent implements feedback by calculating characteristic variation values for each wafer lot and using this information to determine optimal placement locations. The system continuously monitors and adjusts the dispatch decisions based on the calculated characteristics, creating a closed-loop control system that improves manufacturing precision through data-driven placement strategies
Solution Approach 2:
The system performs preliminary calculation of characteristic variation values before the actual furnace placement. By pre-calculating and pre-ordering the wafer lots based on their characteristics, the system prepares the optimal placement sequence in advance, which simplifies the actual dispatch execution and reduces complexity during the critical processing phase
Data Source
AI summary
A dispatch control method for a furnace process including the following steps is provided. Before a plurality of lots of wafers is loaded into a furnace, the characteristic variation value of each of the plurality of lots of wafers is calculated. The plurality of lots of wafers is ordered according to the size of the characteristic variation values. The plurality of lots of wafers is placed in the furnace in a descending order of the characteristic variation values corresponding to a plurality of locations in the furnace causing the characteristic variation values to change from smaller to larger.