Two-Loop APC Architecture for Semiconductor Process Stability
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Solution Overview
Problem
Current advanced process control (APC) infrastructure in semiconductor manufacturing limits the range of process tuning, requiring manual intervention when equipment parameters drift beyond a fraction of the tool tuning range, leading to reduced manufacturing throughput and potential quality issues.
Innovation Solution
A two-loop architecture combining an APC loop for fine tuning and an equipment performance optimization (EPO) loop for recovery tuning, with a synergy mechanism to avoid double-tuning, allowing automated adjustment of equipment parameters to restore tool baseline values and maintain process stability within specified limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If APC loop is used for fine tuning process parameters, then manufacturing precision is improved, but the tuning range is limited to a fraction of the complete tool tuning range
Solution Approach 1:
The control system is segmented into two distinct loops: an APC loop for fine-tuning process parameters within a limited range to maintain manufacturing precision, and an EPO loop for recovering equipment parameters that have drifted beyond the APC tuning range. This segmentation allows each loop to specialize in its respective function, resolving the contradiction between precision and tuning range.
Solution Approach 2:
The EPO loop acts as an intermediary that restores equipment parameters to baseline values when they drift beyond the APC loop's tuning range. This intermediary mechanism enables the APC loop to maintain precision within its limited range while the EPO loop handles broader parameter recovery, effectively extending the overall system's adaptability.
2Measurement precision
If manual tuning of equipment parameters is performed to restore tool baseline value, then equipment parameter accuracy is improved, but manufacturing throughput is reduced due to downtime
Solution Approach 1:
The EPO loop implements self-service by automatically detecting when equipment parameters drift beyond the APC tuning range and autonomously restoring them to baseline values. This eliminates the need for manual intervention and associated downtime, maintaining both parameter accuracy and manufacturing throughput.
Solution Approach 2:
The system incorporates continuous feedback monitoring of equipment parameters. When parameters drift beyond acceptable thresholds, the feedback mechanism triggers the EPO loop to automatically restore baseline values, ensuring parameter accuracy is maintained without requiring manual intervention that would reduce throughput.
3Device complexity
If APC loop operates independently without EPO loop integration, then system complexity is reduced, but process stability deteriorates when equipment parameters drift beyond tuning range
Solution Approach 1:
The system merges the APC loop and EPO loop into a unified two-loop architecture where the APC loop handles fine-tuning within its limited range and the EPO loop handles parameter recovery when drift occurs. This combination maintains process stability across the complete tool tuning range while managing complexity through clear division of responsibilities between the two loops.
Data Source
AI summary
The present disclosure relates to an APC method and tool architecture to elaborate process stability, comprising a two-loop architecture for fine tuning by an APC loop and recovery tuning by an equipment performance optimization (EPO) loop of one or more process parameters. Fine tuning by the APC loop comprises neutralization of systematic drifts from manufacturing tool or the manufacturing process itself. Recovery tuning by the EPO loop comprises aligning processing tool conditions with their tool baseline configuration. The APC method and tool architecture establishes switching criteria for fine tuning of process parameters and recovery tuning of equipment parameters. A synergy mechanism is further established between the two loops, wherein adjustments to equipment parameters made by the EPO loop are recognized by the APC loop to avoid double-tuning. The APC method and tool architecture results in manufacturing process stability within a manufacturing process module.