3D NAND Staircase CD Control via Interferometric Endpoint Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in manufacturing next-generation semiconductor devices lies in reliably forming sub-half micron features and stair-like structures with precise dimension control, as inaccuracies in photoresist trimming and etching rates lead to asymmetric structures, affecting channel placement and device performance.
Innovation Solution
The method involves using interferometric endpoint detection to accurately control the photoresist trimming and etching processes by analyzing reflected optical signals, ensuring precise dimension control and profile uniformity of stair-like structures in 3D stacked semiconductor chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photoresist trimming and etching processes are performed without interferometric endpoint detection, then manufacturing process is simpler and faster, but manufacturing precision of stair-like structures deteriorates
Solution Approach 1:
The patent implements real-time feedback control by using interferometric endpoint detection to monitor the photoresist trimming and etching processes. The system continuously measures the reflected optical signals and adjusts the process parameters to maintain precise dimension control of stair-like structures, resolving the contradiction between manufacturing precision and process complexity.
Solution Approach 2:
The patent replaces traditional mechanical measurement and control methods with optical interferometric detection. By using optical signals to monitor process endpoints and control dimensions, the system achieves higher precision without proportionally increasing mechanical complexity.
2Manufacturing precision
If photoresist trimming rate or etching rate is not accurately controlled, then manufacturing process is easier to operate, but manufacturing precision of stair-like structures deteriorates
Solution Approach 1:
The interferometric endpoint detection system provides real-time feedback on the trimming and etching rates by analyzing reflected optical signals. This enables automatic adjustment of process parameters to maintain accurate width control of each stair structure, eliminating the need for complex manual control while achieving high precision.
Solution Approach 2:
The system enables self-controlled process regulation where the interferometric detection automatically monitors and adjusts the trimming and etching rates without requiring constant operator intervention. The process controls itself through automated feedback loops, improving precision while maintaining ease of operation.
3Manufacturing precision
If interferometric endpoint detection is used to control photoresist trimming and etching, then manufacturing precision of stair-like structures is improved, but use of energy and device complexity increase
Solution Approach 1:
The patent replaces energy-intensive mechanical measurement systems with optical interferometric detection. The optical system consumes less energy while providing superior measurement precision for controlling the trimming and etching processes, achieving dimensional accuracy without proportionally increasing energy consumption.
Solution Approach 2:
The system optimizes the operational parameters of the interferometric detection system to minimize energy consumption while maintaining high measurement precision. By adjusting optical parameters such as light source intensity and detection sensitivity, the system achieves the required dimensional accuracy with reduced energy input.
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
This approach enables the formation of symmetric stair-like structures with precise dimensions, improving channel placement accuracy and overall device performance by determining the endpoint of the photoresist trimming and etching processes, thus enhancing the manufacturing of 3D stacked semiconductor chips.
Implementation Method 1
determining a trimming endpoint by analyzing the return optical signal reflected from the photoresist layer
Implementation Method 2
collecting a return reflected optical signal reflected from the photoresist layer
Data Source
AI summary
Embodiments of the present disclosure provide methods for forming stair-like structures in manufacturing three dimensional (3D) stacking of semiconductor chips. In one example, a method includes performing a trimming process on a substrate to trim a patterned photoresist layer disposed on a film stack from a first width to a second width in a processing chamber, performing an etching process to etch a portion of the film stack exposed by the trimmed patterned photoresist layer, directing an optical signal to a surface of the trimmed patterned photoresist layer continuously during the trimming and the etching process, collecting a return reflected optical signal reflected from the trimmed patterned photoresist layer, determining a change of reflected intensify of the return reflected optical signal as collected; and calculating a photoresist thickness loss based on the change of the reflected intensity.