Silicon Recess Filling with Dual-Profile Etching to Prevent Voids
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Solution Overview
Problem
Conventional DED processes struggle to fill recesses with silicon films without generating voids, especially when the recesses have uneven lateral surfaces, as the existing methods fail to effectively widen the opening width uniformly.
Innovation Solution
A method involving a substrate processing device that uses two types of etching gases with different etching profiles in a two-step etching process to widen the opening width of recesses, ensuring uniform filling of silicon films without voids, even in recesses with uneven surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single etching gas is used in conventional DED process, then the process is simple, but the opening width of recess cannot be widened uniformly, causing void formation
Solution Approach 1:
The etching process is divided into two distinct steps using two different etching gases: a first etching gas (e.g., Cl2) to widen the upper opening, and a second etching gas (e.g., CF4) to etch the lower recess. This segmentation allows each gas to target specific regions, achieving uniform opening widening and preventing void formation while maintaining process control
Solution Approach 2:
Different etching gases with different properties are applied to different spatial regions of the recess. The first etching gas primarily affects the upper opening region, while the second etching gas targets the lower recess region. This local differentiation ensures uniform etching across the entire recess depth without causing voids
2Reliability
If conventional single-step etching is used, then the process is fast, but voids are formed in recesses with uneven lateral surfaces
Solution Approach 1:
The etching process is divided into two distinct steps using two different etching gases: a first etching gas (e.g., Cl2) to widen the upper opening, and a second etching gas (e.g., CF4) to etch the lower recess. This segmentation allows each gas to target specific regions, achieving uniform opening widening and preventing void formation while maintaining process control
Solution Approach 2:
The first etching gas performs preliminary widening of the upper opening before the second etching gas acts on the lower recess. This preliminary action creates a favorable geometry that enables subsequent uniform filling without voids, addressing the root cause of the reliability issue
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 effectively fills recesses with silicon films without voids by using a first etching gas to create a clear V-shape and a second etching gas to achieve conformal etching, ensuring the silicon film reaches and fills the recesses uniformly, addressing the challenge of uneven surface recesses.
Implementation Method 1
supplying a silicon-containing gas to a substrate having a recess formed in a surface of the substrate to deposit a silicon film in the recess
Implementation Method 2
supplying, to the substrate, a first etching gas having a first etching profile in which an amount of etching for an upper portion of the recess in a depth direction and an amount of etching for a lower portion of the recess in the depth direction are different from each other, to etch the silicon film in the recess
Implementation Method 3
supplying, to the substrate, a second etching gas having a second etching profile that is different from the first etching profile of the first etching gas to etch the silicon film in the recess
Data Source
AI summary
A method for manufacturing a semiconductor device includes supplying a silicon-containing gas to a substrate having a recess formed in a surface of the substrate to deposit a silicon film in the recess, supplying, to the substrate, a first etching gas having a first etching profile in which an amount of etching for an upper portion of the recess in a depth direction and an amount of etching for a lower portion of the recess in the depth direction are different from each other, to etch the silicon film in the recess, supplying, to the substrate, a second etching gas having a second etching profile that is different from the first etching profile of the first etching gas to etch the silicon film in the recess, and additionally depositing the silicon film on the already deposited silicon film etched by the second etching gas.