PE-CVD Gas Inlet Structure for Wafer Edge Protection Deposition
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Solution Overview
Problem
Conventional methods for protecting the peripheral regions of semiconductor wafers during etching processes, such as using photoresist polymers, can interfere with the etching process and are not suitable for bulk silicon etches, necessitating an alternative method that is convenient, compatible with existing technologies, and provides controlled protection.
Innovation Solution
A capacitively coupled Plasma Enhanced Chemical Vapour Deposition (PE-CVD) apparatus with a gas inlet structure featuring an edge region and a central region that depends downwardly, creating a plasma dark space channel, allowing for location-specific deposition of materials onto the peripheral regions of substrates without affecting central areas, using RF power to generate a plasma that deposits materials only on the desired peripheral regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photoresist polymer is applied to protect the peripheral region of the wafer, then the peripheral region is protected during etching, but the chemicals in the photoresist interfere with the etching process
Solution Approach 1:
The patent extracts and removes the harmful photoresist chemicals from the etching process by using an alternative protection method. A deposit of material is formed on the peripheral region before etching, and this deposit serves as the protective layer without introducing interfering chemicals into the etching environment
Solution Approach 2:
The patent introduces a deposited material layer as an intermediary between the peripheral region and the etching process. This intermediary layer provides protection during etching without the chemical interference problems associated with photoresist polymers
2Reliability
If material is deposited onto the peripheral region of the substrate, then protection is provided during etching, but deposition must be location-specific to avoid protecting areas intended to remain exposed
Solution Approach 1:
The patent applies local quality by creating a deposit with spatially varying properties. The deposit thickness and material composition are controlled to provide protection only in the peripheral region, while leaving the central region exposed. This is achieved through controlled deposition processes that target specific areas of the substrate
Solution Approach 2:
The patent segments the substrate into protected peripheral regions and exposed central regions through selective deposition. The deposit is applied in a controlled manner to specific zones, creating distinct functional areas 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
Enables controlled, location-specific deposition of protective materials like silicon oxide around the wafer edges, preventing interference with the etching process and ensuring protection during subsequent etching steps, with adjustable deposition thickness and distribution by varying structural and process parameters.
Implementation Method 1
performing a capacitively coupled PE-CVD process in which RF power is supplied to the gas inlet structure to generate a plasma which has a dark space in the plasma dark space channel
Implementation Method 2
capacitively coupled Plasma Enhanced Chemical Vapour Deposition (PE-CVD)
Data Source
AI summary
A capacitively coupled Plasma Enhanced Chemical Vapour Deposition (PE-CVD) apparatus has a chamber, a first electrode with a substrate support positioned in the chamber, a second electrode with a gas inlet structure positioned in the chamber, and an RF power source connected to the gas inlet structure for supplying RF power thereto. The gas inlet structure has an edge region, a central region which depends downwardly with respect to the edge region, and one or more precursor gas inlets for introducing a PE-CVD precursor gas mixture to the chamber. The edge region and the central region both constitute part of the second electrode. The precursor gas inlets are disposed in the edge region and the central region is spaced apart from the substrate support to define a plasma dark space channel.