Air Gap Insulating Layer Deposition for RC Delay Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices become finer, the spacing between cells narrows, leading to RC delays due to parasitic capacitance and structural issues like film cracking and contact misalignment.
Innovation Solution
A substrate processing method that forms an air gap between patterned structures by depositing thin films with varying step coverage and plasma power, concentrating gas and ions on upper portions to maximize air gap formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the spacing between cells is narrowed to increase device density, then device integration is improved, but RC delay increases due to parasitic capacitance
Solution Approach 1:
The patent applies local quality by creating an air gap structure specifically in the region between adjacent cell electrodes, while maintaining the narrowed spacing. The air gap is formed by depositing a gap-fill dielectric material that has a lower dielectric constant than the surrounding insulating materials, thereby locally reducing parasitic capacitance only where needed between cells, without affecting other areas of the device structure.
2Reliability
If a gap-fill dielectric material is used to reduce parasitic capacitance, then RC delay is reduced, but structural deformation such as film cracking and contact misalignment occurs
Solution Approach 1:
The patent segments the gap-fill structure into multiple functional layers: a lower insulating layer, a gap-fill dielectric material layer with air gaps, and an upper insulating layer. The air gaps are created by controlling the deposition process to leave void spaces within the gap-fill material. This segmentation allows the structure to maintain mechanical integrity while achieving the desired low dielectric constant, preventing film cracking and contact misalignment.
Solution Approach 2:
The patent creates a porous structure within the gap-fill dielectric material by forming air gaps through controlled deposition. The air gaps act as void spaces that reduce the overall dielectric constant of the gap-fill material. This porous approach allows the material to maintain structural integrity while achieving the electrical performance needed to reduce parasitic capacitance, thereby preventing structural deformation.
3Manufacturing precision
If conventional thin film deposition is used to form insulating layers, then uniform coverage is achieved, but air gap formation is insufficient
Solution Approach 1:
The patent employs dynamic control of deposition parameters during the thin film deposition process. By adjusting deposition conditions such as plasma power, pressure, and gas flow rates, the deposition rate is modulated to be slower in regions where air gaps are desired. This dynamic control allows the formation of air gaps within the insulating layers while maintaining adequate film coverage on the surface, resolving the contradiction between uniform coverage and air gap formation.
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 reduces dielectric constant, prevents RC delays, and minimizes structural deformation by creating a void or air gap between the patterned structures, enhancing the performance and reliability of semiconductor devices.
Implementation Method 1
pressure in a reaction space is maintained at a first pressure value, and the power of plasma is set to a first power value
Implementation Method 2
forming a first insulating layer having a first step coverage on a patterned structure
Implementation Method 3
a mean free path of gas supplied to the reaction space is reduced by the second pressure value, so that the gas is concentrated on upper portions of the first and second protrusions
Implementation Method 4
the amount of ions generated in the reaction space is reduced by the second power value, thereby reducing the ion density, and the ions may be concentrated on the upper portions of the first and second protrusions
Data Source
AI summary
A substrate processing method of easily forming an air gap includes: forming a first insulating layer having a first step coverage on a patterned structure including a first protrusion and a second protrusion; and forming, on the first insulating layer, a second insulating layer having a second step coverage lower than the first step coverage, wherein an air gap is formed between the first protrusion and the second protrusion by repeating the forming of the second insulating layer.