Memory Active Area Layout to Prevent Edge Collapse and Stress
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Solution Overview
Problem
Existing memory technologies face issues with edge collapse and stress in active area arrays due to small active area sizes, affecting product yield and reliability as storage density increases.
Innovation Solution
A method involving multiple mask layers and etching processes to form discrete active areas with a shallow trench isolation structure, where strip-shaped patterns are created and connected to the peripheral area, preventing edge collapse and stress by forming a continuous active area array that is then divided into discrete areas with a peripheral trench.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If SADP process is employed to form active area with smaller line width to increase storage density, then storage capacity increases, but active area size becomes very small causing edge collapse and stress problems
Solution Approach 1:
The patent segments the active area formation process into two distinct stages: first forming continuous active areas that extend to the peripheral region, then dividing them into discrete active areas. This segmentation allows the continuous areas to provide structural support during formation, preventing edge collapse, while the final discrete areas achieve the required small size for high storage density.
Solution Approach 2:
The patent performs preliminary action by first forming continuous active areas that extend to the peripheral region before dividing them into discrete areas. This preliminary continuous structure provides mechanical support and prevents edge collapse during the formation process, addressing the reliability issue before the final high-density discrete structure is created.
2Quantity of substance
If active area size is reduced to increase storage density, then storage capacity increases, but manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent segments the patterning process into two stages using different mask layers. The first mask layer forms continuous active areas with larger dimensions that are easier to manufacture with high precision. The second mask layer then divides these continuous areas into smaller discrete areas. This segmentation allows each stage to be optimized for its specific precision requirements, maintaining overall manufacturing precision while achieving high storage density.
Solution Approach 2:
The patent uses a two-layer mask structure that adds a vertical dimension to the patterning process. The first mask layer defines the continuous active area regions, and the second mask layer defines the division trenches. This dimensional approach allows independent optimization of each patterning step, making it easier to maintain manufacturing precision while achieving the required small active area sizes for high density.
3Ease of manufacture
If continuous active area is divided into discrete active areas to form array, then memory structure is formed, but edge of active area array experiences collapse and stress
Solution Approach 1:
The patent performs preliminary action by forming continuous active areas that extend to the peripheral region before dividing them into discrete areas. This preliminary continuous structure provides mechanical support and prevents edge collapse during the formation process, addressing the reliability issue before the final high-density discrete structure is created.
Solution Approach 2:
The continuous active area structure acts as an intermediary between the substrate and the final discrete active areas. During the division process, this continuous structure serves as a mediator that distributes stress and prevents edge collapse, while still allowing the formation of the desired discrete array structure.
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 method effectively prevents edge collapse and reduces stress on discrete active areas, improving the reliability and yield of memory products by ensuring stable connections and isolation.
Implementation Method 1
etching layer by layer by using the second mask layer and the first mask layer as masks to transfer the strip-shaped patterns and the first patterns into the substrate to form the discrete active areas arranged in an array
Data Source
AI summary
A memory formation method includes: providing a substrate; forming a first mask layer on the substrate, in the first mask layer there being formed a plurality of parallel-arranged strip-shaped patterns positioned above the array area, and an end of each of the strip-shaped patterns being connected to the first mask layer on the peripheral area of the substrate; forming a second mask layer on the first mask layer, in the second mask layer there being formed a plurality of first patterns; and etching layer by layer by using the second mask layer and the first mask layer as masks to transfer the strip-shaped patterns and the first patterns into the substrate to form the discrete active areas arranged in an array.