Cycle Etching Endpoint Detection via Light Emission Analysis
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Solution Overview
Problem
In cycle etching for semiconductor manufacturing, it is challenging to stably sense changes in light emission intensity with time, making it difficult to detect the etching end point due to the short duration of individual cycles, unlike in typical etching where time for etching is sufficiently secured.
Innovation Solution
A semiconductor manufacturing apparatus that includes an extraction module to monitor and a detection module to analyze light emission intensities across multiple cycles, allowing for the detection of the etching end point by tracking changes in light emission during etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cycle etching is performed with short etching time per cycle to cope with device size shrinkage, then productivity is improved, but measurement precision of light emission intensity deteriorates
Solution Approach 1:
The patent transitions from time-domain measurement (monitoring light emission continuously during etching) to cycle-domain measurement (comparing light emission intensity across multiple etching cycles). By analyzing the temporal evolution of light emission intensity at the same phase of successive cycles, the system achieves accurate endpoint detection despite shortened individual cycle durations.
Solution Approach 2:
The system performs preliminary measurements of light emission intensity at specific phases of multiple etching cycles before making the endpoint determination. By accumulating data from several cycles and identifying trends in advance, the system can accurately detect the endpoint even when each individual cycle is too short for traditional real-time monitoring to be effective.
2Measurement precision
If etching time per cycle is extended to enable stable light emission sensing, then measurement precision is improved, but productivity deteriorates
Solution Approach 1:
The patent employs periodic sampling of light emission intensity at corresponding phases across multiple etching cycles. Instead of requiring continuous monitoring throughout each cycle, the system captures light emission data at specific periodic intervals and compares these snapshots across cycles, enabling accurate endpoint detection with minimal measurement time per cycle.
Solution Approach 2:
The system creates a reference profile of light emission intensity from earlier cycles and compares subsequent cycles against this reference. By copying and comparing the temporal pattern of light emission across cycles rather than requiring extended measurement in each individual cycle, the system achieves precise endpoint detection while maintaining short cycle durations.
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
Enables accurate detection of the etching end point in cycle etching by analyzing light emission intensity changes across cycles, improving the precision and reliability of the process.
Implementation Method 1
light emission intensities in the first processes for individual cycles
Data Source
AI summary
In one embodiment, a semiconductor manufacturing apparatus includes an extraction module configured to extract, in cycle etching that repeats first processes of etching a workpiece layer and second processes of performing different processing from the first processes for plural cycles, light emission intensities in the first processes for individual cycles. The apparatus further includes a detection module configured to detect an etching end point of the workpiece layer in the cycle etching, based on the light emission intensities of the plural cycles.