Exposed Layer Activation Using Sacrificial CxHyFz Plasma Coating
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Solution Overview
Problem
Existing methods for direct bonding of substrates in microelectronic devices face limitations in bonding energy due to etching of the exposed layer during activation plasma treatment, particularly when using fluorinated gases like CF4 and SF6.
Innovation Solution
A method involving the deposition of a layer based on a material with chemical formula CxHyFz before activation plasma treatment, which consumes the layer to activate the substrate, thereby increasing bonding energy while minimizing etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fluorinated gas (CF4 or SF6) is injected into oxygen-based activation plasma to increase bonding energy, then bonding energy between substrates is improved, but etching of the exposed layer occurs
Solution Approach 1:
The process is divided into two separate steps: first depositing the fluorinated layer (CxHyFz) onto the exposed layer, then treating with activation plasma to consume the deposited layer. This segmentation allows the fluorinated layer to serve as a sacrificial source that releases fluorine species for activation without directly exposing the substrate to etching fluorinated plasma, thereby resolving the contradiction between achieving high bonding energy and preventing substrate etching
Solution Approach 2:
The deposited fluorinated layer (CxHyFz) acts as an intermediary between the fluorinated gas and the substrate. Instead of introducing fluorinated gas directly into the plasma that contacts the substrate (which causes etching), the fluorinated layer is first deposited as a protective intermediary, then consumed by activation plasma to release fluorine species for activation. This intermediary approach enables fluorine release for bonding energy enhancement while protecting the substrate from direct etching exposure
2Strength
If carbon-containing material (CxHyFz) is deposited on the exposed layer before activation, then fluorine is released during plasma treatment to increase bonding energy, but carbon contamination may occur
Solution Approach 1:
The plasma treatment parameters (power, pressure, gas composition, treatment time) are optimized to control the consumption of the deposited fluorinated layer. By adjusting these parameters, the plasma selectively consumes the fluorinated layer to release fluorine species for activation while removing carbon through gaseous discharge products (CO, CO2, CN), thereby achieving high bonding energy without carbon contamination on the substrate surface
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 enhances bonding energy and reduces etching of the exposed layer, offering improved reproducibility and bonding interface quality compared to existing solutions.
Implementation Method 1
a deposition in the reaction chamber of a layer based on a material of chemical formula CxHyFz
Implementation Method 2
a treatment, in the presence of the structure, of the layer based on a material of chemical formula CxHyFz by an activation plasma based on at least one of oxygen and nitrogen, the treatment by the activation plasma being configured to consume at least in part, preferably totally, the layer based on the material of chemical formula CxHyFz so as to activate the exposed layer of the structure
Data Source
Figure 1~2A
Figure 2B~2D
Figure 3A~3B
AI summary
The invention relates to a method for activating an exposed layer (10) of a structure (1), comprising supplying a structure (1) including an exposed layer (10), and, either before or after supplying the structure (1), depositing a layer (11) based on a material of chemical formula CxHyFz into the reaction chamber, where at least x and z are non-zero. The method further comprises treating the layer (11) based on the CxHyFz material in the presence of the structure (1) with an activation plasma (3) based on at least one of oxygen and nitrogen. The treatment with the activation plasma (3) is configured to consume at least part of the layer (11) based on the CxHyFz material so as to activate the exposed layer (10) of the structure (1).