Capacitor Hard Mask Segmentation for Trench Stability
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Solution Overview
Problem
As semiconductor devices, particularly memory devices, scale to smaller dimensions, the formation of deeper and narrower trenches for capacitors increases the risk of bending and wobbling, leading to potential shorts and reduced capacitance due to stress on the capacitor material.
Innovation Solution
A method involving a dual lattice structure with a hard mask and sacrificial layer is used to reduce stress on the capacitor material, allowing for increased height and capacitance while minimizing bending and wobbling, by positioning a hard mask and sacrificial layer above the top lattice, and subsequently removing them to expose additional surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the trench depth is increased to achieve higher capacitance, then the capacitance value increases, but the structural stability deteriorates leading to bending and wobbling
Solution Approach 1:
The trench structure is segmented into multiple sections with different fill materials: a first section filled with capacitor material and a second section filled with support material. This segmentation provides structural support within the deep trench, preventing bending and wobbling while maintaining the required capacitance through the capacitor material in the first section.
2Quantity of substance
If the trench depth is increased to achieve higher capacitance, then the capacitance value increases, but the risk of shorts increases due to wobbling
Solution Approach 1:
By dividing the trench into functional sections with appropriate fill materials, the support material in the second section stabilizes the trench walls and prevents wobbling that could lead to shorts, while the capacitor material in the first section maintains the required capacitance.
Solution Approach 2:
The support material is placed in the second section of the trench to provide beforehand cushioning and structural reinforcement, preventing future wobbling and short risks before they occur, thereby ensuring reliable operation of the high-capacitance structure.
3Quantity of substance
If the capacitor material height is increased to achieve higher capacitance, then the capacitance value increases, but the stress on capacitor material increases causing bending
Solution Approach 1:
The capacitor material is confined to the first section of the trench where it can maintain optimal height for capacitance without excessive stress. The second section filled with support material provides structural reinforcement that prevents bending, allowing the capacitor material to achieve higher capacitance values without compromising strength.
Data Source
AI summary
Methods, apparatuses, and systems related to forming a capacitor using a hard mask material are described. An example method includes patterning a surface to have a first silicate material, a first nitride material on the first silicate material, a second silicate material on the first nitride material, a second nitride material on the second silicate material, and a sacrificial material on the second nitride material. The method further includes forming a hard mask material on the sacrificial material. The method further includes forming a capacitor material in an opening through the first silicate material, the first nitride material, the second silicate material, the second nitride material, the sacrificial material, and the hard mask material. The method further includes removing the sacrificial material and the hard mask material.