DRAM Capacitor Dielectric Structure for Tensile Stress Relief
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Solution Overview
Problem
Current manufacturing techniques for Dynamic Random Access Memory (DRAM) devices face challenges in reducing tensile stress in capacitor dielectric films, which can lead to distortion, tilting, and increased risk of short circuits, thereby reducing manufacturing yield.
Innovation Solution
The method involves forming a semiconductor memory structure with a tri-layer capacitor dielectric film, where a first high-k dielectric material is deposited, followed by a second high-k dielectric material, and then a third high-k dielectric material. An annealing process is performed after the deposition of the second high-k dielectric material to release tensile stress, and a top electrode layer is formed on the third high-k dielectric material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capacitor dielectric film is formed using conventional single-layer deposition, then the manufacturing process is simple, but tensile stress accumulates causing distortion, tilting, and short circuits
Solution Approach 1:
The capacitor dielectric film is divided into three separate high-k dielectric material layers deposited sequentially. Each layer can be independently controlled during deposition, allowing stress management while maintaining high capacitance. The segmentation of the dielectric film into multiple layers directly addresses the tensile stress issue while preserving reliability.
Solution Approach 2:
The patent uses composite high-k dielectric material layers with different material compositions and properties. By combining multiple high-k dielectric materials with varying stress characteristics, the overall tensile stress in the capacitor dielectric film is reduced. The composite structure allows optimization of both electrical performance and mechanical stress distribution.
2Productivity
If component sizes are miniaturized to increase DRAM density, then component density increases, but manufacturing precision requirements increase
Solution Approach 1:
Dividing the dielectric film into three separate layers allows each layer to be deposited with precise thickness control. This segmentation enables better management of manufacturing precision requirements at miniaturized scales, as each individual layer can be optimized for uniformity and stress characteristics.
Solution Approach 2:
The patent changes the physical and chemical parameters of the dielectric materials by using different high-k materials with varying properties. This allows optimization of deposition parameters for each layer to achieve the required manufacturing precision while maintaining high component density through miniaturization.
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 effectively reduces tensile stress in the capacitor dielectric film, minimizing the risk of short circuits and improving the manufacturing yield of semiconductor memory devices.
Implementation Method 1
annealing the first and second high-k dielectric materials
Implementation Method 2
after the annealing process, depositing a third high-k dielectric material
Implementation Method 3
depositing a first high-k dielectric material on the bottom electrode layer, depositing a second high-k dielectric material on the first high-k dielectric material
Data Source
AI summary
A method for forming a semiconductor memory structure includes forming a bottom electrode layer over an active region, depositing a first high-k dielectric material on the bottom electrode layer, depositing a second high-k dielectric material on the first high-k dielectric material, annealing the first and second high-k dielectric materials, after the annealing process, depositing a third high-k dielectric material on the second high-k dielectric material, and forming a top electrode layer on the third high-k dielectric material.