Conductive Layer X-ray Shielding for E-beam Deposition
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Solution Overview
Problem
Semiconductor lithography techniques face challenges in accurately transferring patterns without causing radiation damage to underlying substrates, particularly due to X-ray energy effects during electron-beam deposition, which can shift transistor turn-on voltages and lead to inaccurate pattern transfer and substrate damage.
Innovation Solution
A dual-deposition process is employed, where a conductive layer is first deposited using a non-X-ray process like thermal evaporation or sputtering, followed by additional conductive layers deposited using electron-beam physical vapor deposition, with the conductive layer attenuating X-ray energy to prevent damage to the underlying substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electron-beam physical vapor deposition is used to deposit conductive layers, then deposition quality and pattern accuracy are improved, but X-ray energy damages the underlying semiconductor substrate
Solution Approach 1:
A sacrificial conductive layer (first conductive layer) is deposited using thermal evaporation or sputtering to serve as an intermediary barrier between the electron beam deposition source and the semiconductor substrate. This sacrificial layer absorbs the harmful X-ray energy generated during subsequent electron-beam deposition of additional conductive layers, while still allowing the desired material pattern to be transferred accurately to the substrate.
Solution Approach 2:
The sacrificial conductive layer is deposited in advance using a non-X-ray generation process (thermal evaporation or sputtering) before the electron-beam deposition begins. This preliminary action prepares the substrate by providing protective coverage that will be present during the high-precision electron-beam deposition process, preventing X-ray damage before it can occur.
2Object-affected harmful factors
If a sacrificial conductive layer is deposited using thermal evaporation or sputtering, then X-ray damage is prevented, but an additional deposition step is required
Solution Approach 1:
The sacrificial conductive layer and the functional conductive layers are merged into a single integrated structure. The first conductive layer serves dual purposes: as a sacrificial protective barrier during deposition and as part of the final conductive structure on the substrate. After electron-beam deposition completes, the entire conductive structure remains, eliminating the need for separate removal steps.
Solution Approach 2:
The first conductive layer performs multiple functions: (1) serves as a sacrificial barrier during electron-beam deposition to protect the substrate from X-ray damage, (2) provides a foundation for subsequent conductive layers, and (3) remains as part of the final functional conductive structure on the substrate. This multi-functionality reduces process complexity despite adding an initial deposition step.
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 method effectively prevents X-ray-induced damage to semiconductor substrates and devices, maintaining pattern accuracy and reliability by blocking or significantly reducing X-ray energy, thus avoiding shifts in transistor turn-on voltages and substrate alterations.
Implementation Method 1
A conductive layer among the plurality of layers inhibits X-ray energy so as to prevent damage to the underlying semiconductor substrate
Implementation Method 2
additional conductive layers deposited using electron-beam physical vapor deposition
Implementation Method 3
deposited using a non-X-ray process like thermal evaporation or sputtering
Implementation Method 4
deposited using a non-X-ray process like thermal evaporation or sputtering
Data Source
AI summary
A method of fabricating an integrated circuit (IC) includes depositing a photoresist on a semiconductor substrate and patterning the photoresist to expose one or more deposition target areas. The method further includes performing a dual-deposition process that deposits a plurality of layers on the photoresists and on the target areas. A conductive layer among the plurality of conductive layers inhibits X-ray energy so as to prevent damage to the underlying semiconductor substrate.