Semiconductor Device Manufacturing Selective Etching
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Solution Overview
Problem
The increasing number of stacked layers in three-dimensional semiconductor devices leads to various failures, such as the formation of oxide layers due to silicon by-products, which can interfere with the formation of conductive patterns and deteriorate the operational reliability of memory cell transistors.
Innovation Solution
A manufacturing method involving the alternate stacking of interlayer insulating layers and sacrificial insulating layers, where specific etching materials are used to selectively remove sacrificial insulating layers between interlayer insulating layers, minimizing the generation and diffusion of silicon by-products and preventing the formation of oxide layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large number of conductive patterns and interlayer insulating layers are stacked to increase storage capacity, then the storage capacity increases, but various failures occur including oxide layer formation that deteriorates operational reliability
Solution Approach 1:
The patent extracts and removes silicon by-products generated during the etching process of sacrificial insulating layers. By introducing a protective layer that selectively prevents oxide formation on the lower structure while allowing etching to proceed, the harmful silicon by-products are effectively managed, thus maintaining high storage capacity without compromising operational reliability
Solution Approach 2:
The patent introduces a protective layer as an intermediary between the lower structure and the etching environment. This protective layer mediates the interaction by preventing direct contact between silicon by-products and the lower structure, thereby eliminating oxide layer formation while allowing the etching process to continue uninterrupted
2Ease of manufacture
If conventional etching materials are used to remove sacrificial insulating layers, then the etching process is simple, but silicon by-products form oxide layers that interfere with conductive pattern formation
Solution Approach 1:
The protective layer serves as an intermediary that blocks the oxidation of silicon by-products without interfering with the etching process. It allows conventional etching materials to be used while preventing the harmful chemical reaction between silicon by-products and oxygen, thus maintaining manufacturing simplicity while eliminating oxide layer formation
Solution Approach 2:
The protective layer creates an inert environment for the lower structure during the etching process. By preventing oxygen from reaching the silicon by-products, it effectively creates a localized inert atmosphere that prevents oxidation while allowing the etching reaction to proceed normally
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 method reduces the failure rate of three-dimensional semiconductor devices by preventing the formation of oxide layers and enhancing the operational reliability of memory cell transistors.
Implementation Method 1
removing only a portion of each of the sacrificial insulating layers which remains between the slit and the slit-side pillar through a first selective etching process by introducing a first etching material through the slit
Implementation Method 2
performing a second etching using a second etching material that is different from the first etching material for removing remaining portions of the sacrificial insulating layers adjacent to the slit which were not removed with the first etching, and the sacrificial insulating layers between the pillars
Data Source
AI summary
A manufacturing method of a semiconductor device includes: forming pillars in a first region of a stack structure in which interlayer insulating layers and sacrificial insulating layers are alternately stacked; forming a slit in a second region of the stack structure; and removing the sacrificial insulating layers in the first region. In the removing of the sacrificial insulating layers in the first region, a portion of each of the sacrificial insulating layers, which is adjacent to the slit, and a portion of each of the sacrificial insulating layers, which is disposed between the pillars, may be removed using different etching materials.