3D Memory Film Thickness Measurement Using Barrier Layer Signal Blocking
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Solution Overview
Problem
The increasing film thickness in 3D NAND memory devices poses challenges for accurate film thickness measurement due to front-end process variations and fluctuations, leading to deviations between calculated and practical results, and the loading effect caused by pattern density, which complicates distinguishing sources of information and affects measurement reliability.
Innovation Solution
A 3D memory device structure incorporating a barrier layer within the channel hole to block signals within a specific wavelength range, allowing for precise measurement of stack structure thickness by emitting signals and calculating the thickness based on unblocked signals, and a film measurement device using optics critical dimension measurement to obtain the film thickness from the measurement spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the film thickness is increased to increase storage density, then the storage capacity is improved, but the measurement precision deteriorates due to front-end process variations and loading effects
Solution Approach 1:
The patent divides the stack structure into multiple separate stack structures (first stack structure, second stack structure, etc.) along the vertical direction. Each stack structure can be measured independently, isolating the measurement of one stack from the loading effects and process variations of other stacks. This segmentation allows accurate thickness measurement of individual stacks even when the total film thickness is large.
Solution Approach 2:
The patent extracts and removes at least one stack structure from the measurement region during the measurement process. By forming opening regions that expose substrate portions and removing certain stack structures, the measurement signal is isolated to only the remaining stack structures, eliminating the loading effect from multiple stacks and enabling precise thickness measurement of individual stacks.
2Productivity
If the number of stacked layers is increased to improve integration degree, then the storage capacity is improved, but the measurement reliability deteriorates due to interlinkages among variables
Solution Approach 1:
The patent segments the vertically stacked structure into multiple independent measurement units (individual stack structures). By measuring each stack structure separately through selective removal and isolation techniques, the patent eliminates interlinkages among variables from different stacks, ensuring that process variations or fluctuations in one stack do not affect the measurement reliability of other stacks.
3Quantity of substance
If the film thickness is increased to increase storage density, then the storage capacity is improved, but the device complexity increases making it difficult to distinguish measurement sources
Solution Approach 1:
The patent extracts specific stack structures from the measurement region by forming opening regions and selectively removing stacks. This extraction simplifies the measurement system by ensuring that the measurement signal originates from only one or specific stack structures, making it easy to identify and analyze the measurement source without complexity from multiple overlapping stacks.
Solution Approach 2:
The patent introduces opening regions as intermediary structures that expose the substrate and separate individual stack structures. These opening regions act as mediators that isolate measurement signals, allowing clear identification of which stack structure is being measured and eliminating confusion from signals originating from multiple stacks.
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 solution enables accurate and reliable film thickness measurement by isolating the influence of front-end processes and pattern density variations, improving measurement confidence and reducing errors, especially in dual-deck structures where interlinkages among variables complicate existing methods.
Implementation Method 1
a barrier layer disposed in the channel hole for blocking a signal within a first wavelength range
Implementation Method 2
emitting the signal within the first wavelength range to the stack structure; and obtaining a thickness of the stack structure that transmits the signal within the first wavelength range according to the signal within the first wavelength range not blocked by the barrier layer
Data Source
AI summary
A three-dimensional (3D) memory device includes a stack structure including a first stack structure and a second stack structure over the first stack structure, and a barrier layer disposed in a first channel hole in the first stack structure.