Conductive Coating for Charge Dissipation in High Aspect Ratio Etching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Charge build-up during high aspect ratio etching of contact holes in integrated circuits leads to twisting and misalignment, causing defects in the formation of vertically straight contact holes, which affects the electrical contact with the active area landing region.
Innovation Solution
A dissipation material, such as metallic materials like titanium or titanium nitride, is deposited on the semiconductor substrate and sputtered into the cavities to form conductive paths that dissipate electrical charges, preventing ion deflection and ensuring vertical sidewall profiles during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high aspect ratio etching is performed to achieve narrow contact holes, then manufacturing precision is improved, but charge build-up occurs on cavity surfaces causing contact hole twisting and misalignment
Solution Approach 1:
A conductive coating layer is deposited on the cavity surface to act as an intermediary that dissipates charge build-up during etching. This coating layer serves as a mediator between the ion bombardment and the underlying film, preventing charge accumulation that would otherwise cause contact hole twisting and misalignment.
Solution Approach 2:
The conductive coating is deposited on the cavity surface before the etching process begins. This preliminary action ensures that the charge dissipation mechanism is already in place before ion bombardment starts, preventing charge build-up from the outset rather than attempting to correct it afterward.
2Productivity
If ion bombardment is increased to improve etching rate, then productivity is improved, but charge build-up on surfaces increases causing contact hole twisting
Solution Approach 1:
The conductive coating layer serves as a mediator that allows higher ion bombardment rates to be used for improved productivity while simultaneously providing a pathway for charge dissipation. The coating enables the system to tolerate higher etching rates without suffering from the charge build-up side effects.
Solution Approach 2:
The conductive coating converts the harmful effect of ion bombardment (charge build-up) into a beneficial situation by providing a controlled pathway for charge dissipation. The same ion bombardment that causes charge accumulation is now managed by the coating, allowing high productivity to be maintained without contact hole twisting.
3Adaptability or versatility
If contact hole width is decreased to increase circuit density, then adaptability is improved, but aspect ratio increases making vertical etching more difficult
Solution Approach 1:
The conductive coating acts as an intermediary that enables the etching of narrower contact holes with higher aspect ratios. By dissipating charge along the cavity surface, the coating prevents the twisting that would otherwise occur in high aspect ratio structures, making it possible to achieve the required circuit density while maintaining verticality.
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 solution effectively reduces charge build-up, maintaining vertical contact hole profiles and ensuring proper alignment and electrical contact with the active area landing region, thereby improving the reliability of contact hole formation in high aspect ratio etching processes.
Implementation Method 1
A dissipation material, such as metallic materials like titanium or titanium nitride, is deposited on the semiconductor substrate and sputtered into the cavities to form conductive paths that dissipate electrical charges
Implementation Method 2
form conductive paths that dissipate electrical charges, preventing ion deflection and ensuring vertical sidewall profiles during etching
Implementation Method 3
The ions and radicals in the plasma that form the etchants are accelerated by an electric field against the material to be etched
Implementation Method 4
A plasma is a gas which contains positive, negative, and neutral atoms, and/or molecules including radicals and a 'gas' of emitted photons
Implementation Method 5
If a chemically inert gas, such as argon, is ionized and accelerated to impinge on a substrate surface, material can be removed from the surface of the substrate by momentum transfer, a process similar to sand blasting
Implementation Method 6
Sputter etching and broad-ion beam milling use high-energy, inert gas ions (typically Ar+) to dislodge material from the substrate surface, a highly anisotropic etch process
Data Source
AI summary
Structures and methods for the dissipation of charge build-up during the formation of cavities in semiconductor substrates.