Selective Etch Stop Capping for Fully Landed Metal Vias
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Solution Overview
Problem
Existing methods for fabricating dual damascene structures can lead to shorts due to vias exposing the underlying dielectric layer during etching, causing potential shorts.
Innovation Solution
A method involving oxide removal, self-assembled monolayer deposition, and subsequent layers like aluminum oxide, silicon oxycarbonitride, and silicon nitride are applied to ensure vias land on metal without exposing the dielectric layer, enhancing via size and reducing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an etch process is used to form vias open to metal layers, then via formation is achieved, but the underlying dielectric layer can be exposed leading to shorts
Solution Approach 1:
A self-assembled monolayer (SAM) is deposited on the metal layer before the etch process. This preliminary layer acts as a protective barrier that prevents the etch process from exposing the underlying dielectric layer, thereby preventing shorts while still allowing via formation to occur.
Solution Approach 2:
The self-assembled monolayer (SAM) serves as an intermediary layer between the metal layer and the underlying dielectric layer. During the etch process, this intermediate layer protects the dielectric from exposure while allowing the via to be formed through the metal layer.
2Reliability
If multiple deposition layers are added to protect against shorts, then short prevention improves, but process complexity increases
Solution Approach 1:
The self-assembled monolayer forms through a self-organizing process where molecules automatically arrange themselves on the metal surface. This self-service mechanism creates the protective layer without requiring complex deposition equipment or multi-step processes, thereby improving short prevention while minimizing added process complexity.
Solution Approach 2:
Rather than adding multiple thick protective layers, a single thin self-assembled monolayer serves as an effective intermediary that provides sufficient protection against shorts. This single intermediate layer achieves the desired reliability improvement with minimal increase in process complexity compared to multiple deposition steps.
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 allows vias to land on metal without shorting, increasing via size by about 25% and reducing resistance by 25-50%, thus improving substrate processing efficiency.
Implementation Method 1
selectively depositing a self-assembled monolayer (SAM) on the metal layer using atomic layer deposition
Implementation Method 2
supplying at least one of hydrogen (H2) or ammonia (NH3) to remove the self-assembled monolayer (SAM)
Implementation Method 3
depositing one of a silicon oxycarbonitride (SiOCN) layer or a silicon nitride (SiN) layer atop the metal layer and the one of the aluminum oxide (AlO) layer on the dielectric layer
Data Source
AI summary
Methods and apparatus for processing a substrate are provided which include removing oxide from a metal layer disposed in a dielectric layer on the substrate disposed in a processing chamber, selectively depositing a self-assembled monolayer on the metal layer using atomic layer deposition, depositing a precursor while supplying water to form one of an aluminum oxide layer on the dielectric layer or a low-k dielectric layer on the dielectric layer, supplying at least one of hydrogen or ammonia to remove the self-assembled monolayer, depositing one of a silicon oxycarbonitride layer or a silicon nitride layer atop the metal layer and the one of the aluminum oxide layer on the dielectric layer or the low-k dielectric layer on the dielectric layer; and depositing a silicon carbon nitride layer atop the one of the silicon oxycarbonitride layer or the silicon nitride layer.