Shower Head Gas Diffusion Space Uniformity
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Solution Overview
Problem
Existing film forming apparatuses face challenges in achieving high in-plane uniformity of film thickness and efficient gas replacement, leading to variations in film deposition on semiconductor wafers, particularly due to differences in reactant gas flow speeds and complex shower head structures.
Innovation Solution
A film forming apparatus with a shower head having a gas diffusion space smaller than the wafer, featuring annular protrusions and gas supply units with horizontal gas discharge openings, allowing for uniform gas distribution and rapid replacement of reactant gases, ensuring high in-plane uniformity and efficient film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large gas diffusion space is used to cover the entire wafer surface, then gas distribution coverage is improved, but gas replacement time increases significantly
Solution Approach 1:
The gas supply system is segmented into multiple independent gas supply units distributed across the shower head, each with its own gas supply line and control valve. This allows selective supply and replacement of reactant gases in different regions, enabling faster gas replacement while maintaining adequate coverage of the wafer surface.
2Device complexity
If gas supply lines are positioned directly below gas supply openings in the shower head, then gas supply simplicity is improved, but flow speed differences cause film thickness non-uniformity
Solution Approach 1:
The gas supply system implements local quality control by positioning gas supply lines at different locations and orientations relative to the gas supply openings. Gas supply lines are arranged to supply gas to specific regions of the wafer, with each line's position and angle optimized to achieve uniform gas distribution and consistent film thickness across the wafer 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
The apparatus achieves improved in-plane uniformity of film thickness and efficient gas replacement, reducing the time required for gas replacement and enhancing the consistency of film deposition on semiconductor wafers.
Implementation Method 1
gas supply units (4) provided at a ceiling portion (31) above the shower head (5), and configured to have gas discharge openings (42) formed along a circumferential direction to allow a gas to be horizontally diffused to a diffusion space surrounded by the shower head (5) and the ceiling portion (31)
Data Source
AI summary
A film forming apparatus for performing a film forming process by sequentially supplying a plurality of reactant gases to a substrate and supplying a replacement gas includes a mounting table configured to mount thereon a substrate, and a shower head having a flat surface facing the mounting table and a plurality of gas supply opening. An annular protrusion is provided at the shower head to form a gap between the annular protrusion and a top surface of the mounting table. A plurality of gas supply units is provided at a ceiling portion at an upper side of the shower head. Each gas supply unit has gas discharge openings formed along a circumferential direction. The diffusion space is disposed such that an outer periphery of the diffusion space is located at an inner side of an outer periphery of the substrate mounted on the mounting table in a plan view.