Interconnect Contact Structure for Precise Via Landing Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in the semiconductor industry is controlling the position of interconnect structures during dual damascene operations, leading to voltage breakdown and leakage issues due to misalignment of metal vias and conductive material voids in the inter-metal dielectrics, which deteriorate the yield rate and reliability of interconnect structures.
Innovation Solution
The solution involves forming a sacrificial bilayer with distinct properties and removing specific portions of it to control the landing area of the metal via, ensuring accurate alignment and reducing the risk of damage to the metal line and inter-metal dielectrics, thereby enhancing the conductivity and reliability of the interconnect structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dual damascene operation is used to form interconnect structures, then the functional density increases and geometry size decreases, but the position control of interconnect structures deteriorates leading to voltage breakdown and leakage
Solution Approach 1:
The patent segments the interconnect formation process into multiple distinct steps: forming mandrels, depositing first conductive material, forming trenches, depositing second conductive material, and planarization. This segmentation allows precise control of each layer's position and dimensions independently, resolving the position control issues in dual damascene operations
Solution Approach 2:
The patent performs preliminary actions by forming mandrels and first conductive material layers before creating trenches and subsequent conductive layers. This sequential preliminary action ensures that each layer is properly positioned and prepared before the next step, preventing misalignment and position control deterioration
2Productivity
If geometry size is scaled down to increase production efficiency, then functional density increases, but position control difficulty increases leading to yield rate deterioration
Solution Approach 1:
The patent transitions from planar dual damascene structures to three-dimensional stacked conductive layers with vertical trenches. This dimensional change allows position control in multiple spatial dimensions, compensating for the reduced tolerance in scaled-down geometries and maintaining manufacturing precision despite increased productivity demands
3Ease of manufacture
If conventional dual damascene process is used, then interconnect structures can be formed, but misalignment of metal vias and conductive material voids occurs reducing yield rate
Solution Approach 1:
The patent introduces mandrels as intermediary structures that guide the formation of trenches and subsequent conductive material deposition. These mandrels serve as precise templates that ensure proper alignment between metal vias and conductive material, eliminating misalignment issues while maintaining ease of manufacture
Solution Approach 2:
The patent replaces the conventional mechanical alignment system with a self-aligned chemical deposition process. The conductive material is deposited conformally on the trench walls and mandrel surfaces, and subsequent planarization automatically aligns layers, substituting mechanical positioning with chemical and physical self-alignment mechanisms
Data Source
AI summary
The present disclosure provides an interconnect structure, including a first metal line, a second metal line spaced away from the first metal line, a conductive contact over the first metal line, including a first portion, a second portion over the first portion, wherein a bottom width of the second portion is greater than a top width of the first portion, wherein a shortest distance between the second portion and the second metal line is in a range from 50 Angstrom to 200 Angstrom, and a third portion over the second portion, wherein a bottom width of the third portion is greater than a top width of the second portion, the entire first portion and the entire second portion are under a coverage of a vertical projection area of the third portion, a first layer, and a second layer over the first layer.