Integrated Metrology Chamber for Etch Depth Control
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Solution Overview
Problem
Conventional photomask manufacturing processes lack efficient integrated metrology tools for precise measurement of etch depth and phase shift angle, leading to increased process cycle time and defect counts due to the need for multiple etch depth measurements in systems not integrated with the etching process.
Innovation Solution
An integrated metrology system that includes a measurement cell coupled to an etch processing system, allowing for optical etch depth measurement through a robot with a substrate transfer mechanism, enabling precise measurement of etch depth without breaking vacuum, thus reducing process time and defect generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional photomask manufacturing processes use separate metrology tools for etch depth measurement, then measurement capability is provided, but process cycle time increases and defect counts increase due to multiple transfers and vacuum breaks
Solution Approach 1:
The patent combines the metrology chamber with the etch chamber into a single integrated vacuum environment. The metrology tool is positioned within the etch chamber, allowing etch depth measurements to be performed without transferring substrates between separate vacuum systems. This integration eliminates vacuum breaks and reduces process cycle time while maintaining measurement precision.
Solution Approach 2:
The integrated metrology system allows continuous measurement of etch depth during the etching process without interrupting the vacuum environment. Substrates can be measured in-situ between etching steps, enabling continuous process monitoring and adjustment without breaking vacuum or transferring substrates to external metrology tools.
2Manufacturing precision
If multiple etch depth measurements are performed in non-integrated systems, then etch depth control is achieved, but defect counts increase due to repeated substrate transfers and vacuum breaks
Solution Approach 1:
The metrology chamber is integrated within the etch chamber vacuum environment, allowing multiple etch depth measurements to be performed without transferring substrates to external tools. This eliminates the risk of contamination and defects associated with repeated vacuum breaks and substrate transfers, while maintaining precise etch depth control through in-situ measurements.
Solution Approach 2:
The integrated vacuum environment serves as a protected inert atmosphere that prevents substrate contamination during measurements. By performing all etch depth measurements within the sealed vacuum environment of the etch chamber, the system eliminates exposure to ambient air and potential contaminants that would occur during substrate transfers to external metrology tools.
3Manufacturing precision
If phase shift masks use translucent layers for phase shifting, then resolution is improved, but precise control of phase shift angle requires multiple measurements increasing process complexity
Solution Approach 1:
The integrated metrology system combines multiple measurement functions within a single chamber, allowing phase shift angle control to be achieved through in-situ measurements during the etching process. The system can perform multiple measurements without requiring separate external metrology tools, reducing process complexity while maintaining precise phase shift angle control.
Solution Approach 2:
The integrated metrology tool provides real-time feedback on etch depth and phase shift angle during the manufacturing process. This feedback enables dynamic adjustment of etching parameters to achieve precise phase shift angle control, reducing the need for multiple iterative measurements and process steps.
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
The integrated metrology system allows for precise control of etch depth and phase shift angle, reducing process time and defect counts by enabling continuous measurement within the same vacuum environment, thereby improving the accuracy and efficiency of photomask manufacturing.
Implementation Method 1
measuring at least one of etch depth or critical dimension using a measurement tool in the measurement cell
Implementation Method 2
etching feature in a quartz layer through a patterned opaque metal layer in the etch chamber
Data Source
AI summary
The embodiments of the invention relate to a method and apparatus for measuring the etch depth in a semiconductor photomask processing system. In one embodiment, a method for etching a substrate includes etching a transparent substrate in an etch chamber coupled to a vacuum transfer chamber of a processing system, transferring the transparent substrate to a measurement cell coupled to the processing system, and measuring at least one of etch depth or critical dimension using a measurement tool in the measurement cell.