Semiconductor Metallization Layers for Uniform Adhesion
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Solution Overview
Problem
Conventional semiconductor processing faces challenges in forming uniform material layers on rough substrates due to self-shadowing, which leads to non-uniform thickness and adhesion issues, requiring additional complex steps like implantation and harsh annealing.
Innovation Solution
A method involving etching processes to smooth rough substrate surfaces, followed by forming adhesion, thick, and thin material layers, which reduces self-shadowing and improves adhesion and contact resistance, using etching tools with specific etchant combinations like HF, HNO3, and H2SO4 to control surface topography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If material layers are formed on rough substrate surfaces using conventional methods, then adhesion and contact resistance are poor, but additional complex processing steps like implantation and harsh annealing are required
Solution Approach 1:
The substrate surface is pre-treated with etching processes before material layer deposition to create a smoothed surface with reduced roughness. This preliminary action eliminates the need for subsequent complex processing steps like implantation and harsh annealing, directly achieving good adhesion and contact resistance
Solution Approach 2:
The surface roughness parameter is changed through controlled etching processes that reduce the height and width ratios of surface features to between 0.2 and 0.5. This parameter change transforms the substrate surface from rough to smoothed, enabling direct material layer formation with proper adhesion without additional complex steps
2Manufacturing precision
If physical deposition processes are used on rough substrates, then self-shadowing occurs leading to non-uniform thickness, but the process should produce uniform material layers
Solution Approach 1:
The substrate surface is pre-smoothed using controlled etching processes that reduce surface feature dimensions before material layer deposition. This preliminary smoothing action eliminates self-shadowing effects during physical deposition, ensuring uniform material layer thickness without requiring process modifications
Solution Approach 2:
The geometric parameters of surface features (height and width) are changed through etching to achieve height-to-width ratios between 0.2 and 0.5. This parameter change reduces self-shadowing during deposition, enabling uniform material layer formation through standard physical deposition processes
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 achieves uniformity in material layer thickness and enhances adhesion and contact resistance, reducing the need for additional complex processing steps and incompatibility issues with other structures and processes.
Implementation Method 1
etching a first surface of a semiconductor substrate from a first side using a first etching process
Implementation Method 2
A conductive layer is formed over the third surface of the semiconductor substrate using a physical deposition process
Data Source
AI summary
A method of fabricating a semiconductor device includes etching a first surface of a semiconductor substrate from a first side using a first etching process to expose a second surface. The second surface includes a first plurality of features. The first plurality of features has an average height that is a first height. The second surface of the semiconductor substrate is etched from the first side using a second etching process to expose a third surface of the semiconductor substrate. The second etching process converts the first plurality of features into a second plurality of features. The second plurality of features has an average height that is a second height. The second height is less than the first height. A conductive layer is formed over the third surface of the semiconductor substrate using a physical deposition process.