Backside Inhibition Gas for Wafer Edge Deposition Uniformity
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Solution Overview
Problem
Achieving uniformity in semiconductor processing across large areas of a wafer is challenging due to discontinuities at the edge regions, which complicates uniform processing.
Innovation Solution
A backside inhibition gas is introduced as part of a deposition-inhibition-deposition (DID) sequence to control uniformity, using a non-plasma inhibition treatment that flows an inhibition gas from both the frontside and backside of the substrate, with the backside gas flow being concurrent, partial overlap, or sequential, to inhibit deposition at the edge regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional deposition processing is performed on large area wafers, then productivity is improved by processing larger substrates, but manufacturing precision deteriorates due to non-uniform deposition at edge regions
Solution Approach 1:
The patent applies local quality by implementing spatially varying inhibition gas flow rates across the wafer surface. The inhibition gas flow is concentrated at edge regions where deposition non-uniformity occurs, while the center regions receive different flow conditions. This localized adjustment of gas flow properties compensates for edge effects and achieves uniform deposition across the entire wafer surface, resolving the contradiction between processing large areas and maintaining film thickness uniformity
2Manufacturing precision
If inhibition gas flow is increased at wafer edges to improve uniformity, then manufacturing precision is improved, but device complexity increases due to additional gas delivery infrastructure
Solution Approach 1:
The gas delivery system is segmented into multiple independent flow channels that can be controlled separately. The inhibition gas delivery is divided into frontside and backside channels with independently controllable flow rates. This segmentation allows precise control of gas distribution patterns without requiring complex overall system redesign, enabling edge region uniformity improvement while managing device complexity through modular flow control
3Manufacturing precision
If non-plasma inhibition treatment is performed with sequential gas flowing, then manufacturing precision is improved by controlling deposition uniformity, but loss of time increases due to additional process steps
Solution Approach 1:
The inhibition gas flow is implemented continuously during the deposition process rather than as separate sequential steps. Both frontside and backside inhibition gases flow simultaneously and continuously throughout deposition, maintaining precise control over deposition uniformity without interrupting the main processing cycle. This continuous action approach achieves spatial uniformity improvement while minimizing additional process time
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 significantly improves uniformity across the substrate, reducing within-wafer non-uniformity from 19% to 4.6% and 24.9% to 4.2% by compensating for frontside depletion at the wafer edge, ensuring consistent film thickness.
Implementation Method 1
performing a non-plasma inhibition treatment on the deposited metal including flowing an inhibition gas from a gas inlet on the frontside of the substrate and flowing the inhibition gas from the backside of the substrate around the edge of the substrate
Implementation Method 2
exposing the features to a metal precursor and a reducing agent to deposit metal in the features
Data Source
AI summary
Provided herein are methods and apparatuses for controlling uniformity of processing at an edge region of a semiconductor wafer. In some embodiments, the methods include providing a backside inhibition gas as part of a deposition-inhibition-deposition (DID) sequence.