Buried Wordline DRAM Isolation Layout Without Trench Etching
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Solution Overview
Problem
Conventional methods for manufacturing buried wordline DRAMs are cumbersome and prone to uneven isolation layer thickness, leading to leakage and poor yield rates due to complex processing steps and inefficient integration.
Innovation Solution
A method involving the formation of a shallow trench isolation structure, ion-doping to create a uniform first isolation layer, and ion-implantation to form a buried wordline structure without etching trenches, simplifying the process and ensuring consistent insulation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional trench etching and isolation layer formation methods are used, then the buried wordline structure can be formed, but the manufacturing process becomes cumbersome and the isolation layer thickness becomes uneven
Solution Approach 1:
The patent extracts and eliminates the trench etching step from the conventional manufacturing process. By directly forming the isolation layer on the substrate surface without creating trenches first, the process complexity is reduced while maintaining precise control over isolation layer thickness through ion doping techniques.
Solution Approach 2:
The patent replaces the mechanical/chemical etching process with an ion doping approach. Instead of physically removing material to create trenches and then filling them, the isolation layer is formed through controlled ion implantation and thermal processing, achieving uniform thickness without the complexity of trench formation.
2Reliability
If conventional isolation layer formation is used, then the buried wordline can be manufactured, but leakage occurs due to uneven thickness
Solution Approach 1:
The patent changes the formation parameters of the isolation layer by using ion doping with controlled dose and energy, followed by thermal processing. This approach allows precise control over the isolation layer thickness and electrical properties, ensuring uniform thickness that prevents leakage and improves device yield rate.
Solution Approach 2:
The patent performs preliminary ion doping to form the isolation layer before forming the buried wordline structure. This preliminary action ensures that the isolation layer is already in place with uniform thickness and appropriate electrical properties, preventing subsequent leakage issues during device operation.
3Productivity
If complex manufacturing steps are used to form the buried wordline, then the structure can be created, but the production efficiency decreases
Solution Approach 1:
The patent merges multiple process steps into a more integrated sequence. By forming the isolation layer first through ion doping, then directly forming the buried wordline on top of it, the patent eliminates intermediate steps such as trench etching, cleaning, and multiple deposition cycles, thereby improving manufacturing efficiency.
Solution Approach 2:
The patent segments the manufacturing process into distinct, optimized stages: (1) isolation layer formation via ion doping, (2) buried wordline formation, and (3) subsequent device processing. This segmentation allows each stage to be optimized independently, reducing overall process complexity and improving productivity.
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 simplifies the manufacturing process, reduces leakage, and ensures stable insulation performance, enhancing the yield and reliability of semiconductor devices.
Implementation Method 1
A first isolation layer is formed in the active region by an ion-doping technique
Implementation Method 2
The active region surrounded by the first isolation layer is ion-implanted to form a first wordline structure
Data Source
AI summary
The disclosure provides a method for manufacturing a semiconductor device. The method includes the following operations. A substrate on which an active region and a shallow trench isolation structure are formed, is provided. A first isolation layer is formed in the active region by an ion-doping technique. The active region surrounded by the first isolation layer is ion-implanted to form a first wordline structure. A second wordline structure is formed in the shallow trench isolation structure, and the first wordline structure and the second wordline structure are connected to form a buried wordline structure extending along a surface of the substrate.