Nitrogen Plasma Etch for Interlayer Dielectric Polymer Control
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Solution Overview
Problem
Conventional plasma etching processes for interlayer dielectric layers in semiconductor manufacturing often result in the formation of polymers at the backside bevel of the wafer, which can lead to flaking and reduce the yield of semiconductor devices, as these polymers are difficult to remove and interfere with subsequent metal deposition.
Innovation Solution
The process modifies the dielectric etch process by using a nitrogen-containing plasma to reduce the formation of polymers at the backside bevel and incorporates a post-etch treatment to strip any remaining polymers, ensuring that the etch process stops at the etch stop layer and uses optimized gas compositions and power settings to prevent polymer deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plasma etching processes are used for interlayer dielectric layers, then the etching process can proceed, but polymers form at the backside bevel which lead to flaking and reduce yield
Solution Approach 1:
The patent modifies the etching process by changing the chemical composition parameters of the plasma, specifically incorporating nitrogen-containing gases (such as N2, NH3, or N2O) into the etching chemistry. This parameter change alters the polymer formation characteristics, transforming the harmful fluorocarbon polymers into removable nitrogen-containing polymer layers that can be stripped during subsequent wet clean steps, thereby eliminating the flaking problem and improving yield
Solution Approach 2:
The patent converts the harmful effect of polymer deposition at the backside bevel into a beneficial outcome by modifying the polymer composition through nitrogen-containing plasma. The resulting nitrogen-containing polymer layer, while still present on the backside, becomes easily removable during standard wet clean processes, transforming a yield-reducing defect into a controllable process feature that does not interfere with subsequent metal deposition
2Object-generated harmful factors
If nitrogen-containing plasma is used to reduce polymer formation, then polymer deposition is reduced, but process complexity increases
Solution Approach 1:
The nitrogen-containing plasma process serves multiple functions simultaneously: it performs the primary dielectric etching, modifies the polymer composition to be removable, and enables integration with existing wet clean steps. This multi-functionality is achieved by selecting nitrogen-containing gases that are compatible with standard semiconductor fabrication processes, requiring no additional equipment or process steps beyond what is already in place
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 significantly reduces polymer formation at the backside bevel, prevents flaking, and allows for efficient in-situ removal of residual polymers, thereby increasing the yield and reliability of semiconductor device manufacturing by ensuring a clean surface for subsequent metal deposition.
Implementation Method 1
providing a plasma on the basis of a dielectric etching process gas, wherein the dielectric etching process gas includes nitrogen (N2), and etching the dielectric layer with the plasma
Implementation Method 2
incorporates a post-etch treatment to strip any remaining polymers
Data Source
AI summary
A high yield plasma etch process for an interlayer dielectric layer of a semiconductor device is provided, according to an embodiment of which a dielectric layer is etched with a nitrogen-containing plasma. In this way, the formation of polymers on a backside bevel of a substrate is avoided or substantially reduced. Remaining polymer at the backside bevel can be removed in situ by post-etch treatment. Further, a plasma etching device is provided comprising a chamber, a substrate receiving space for receiving a substrate, a plasma generator for generating a plasma in the chamber and a temperature conditioner for conditioning a temperature at an outer circumferential region of the substrate receiving space and thereby minimizing temperature gradients at a bevel of the wafer.