Faraday Shield Radial Slots for Plasma Chamber Window Protection
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Solution Overview
Problem
In semiconductor manufacturing, the adherence of non-volatile reaction products to the dielectric window in inductively coupled plasma etching apparatuses interferes with the etching process, leading to reduced magnetic flux transmission and increased chamber cleaning frequency, which affects wafer throughput and feature precision, especially when processing high aspect ratio features.
Innovation Solution
A Faraday shield with a three-zone radial slot configuration, featuring chevron patterns, is placed between the substrate chuck and the dielectric window to prevent deposition on the window while allowing magnetic flux transmission, optimized for correlation with the RF coil placement and tuning circuitry to maintain plasma control and reduce capacitive coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a Faraday shield is placed close to the dielectric window to prevent deposition, then window cleanliness is improved, but magnetic flux transmission is blocked
Solution Approach 1:
The Faraday shield incorporates a porous or slotted structure that allows magnetic flux to pass through while still providing a physical barrier against deposition of reaction products on the dielectric window. The porous configuration enables selective transmission of electromagnetic fields while blocking particulate matter.
Solution Approach 2:
The Faraday shield uses composite material structures combining conductive materials with porous or slotted configurations, creating a composite that simultaneously provides electromagnetic shielding, allows magnetic flux transmission, and prevents deposition. The composite structure integrates multiple functions in a single component.
2Object-affected harmful factors
If the Faraday shield is positioned to block deposition paths, then window protection is improved, but plasma control capability deteriorates
Solution Approach 1:
The Faraday shield employs local quality variations through non-uniform slot distributions, varying slot orientations, or zones of different conductivity that allow different regions to optimize for either deposition protection or plasma control. This localized differentiation enables simultaneous achievement of both functions.
Solution Approach 2:
The Faraday shield incorporates dynamic adjustability through movable components or variable conductivity regions that can be adjusted during operation to optimize the balance between deposition protection and plasma control based on process requirements.
3Object-affected harmful factors
If a solid Faraday shield is used to prevent deposition, then window cleanliness is improved, but chamber cleaning frequency increases due to shield maintenance
Solution Approach 1:
The Faraday shield is designed as a disposable or easily replaceable component that can be quickly removed and replaced without requiring extensive chamber disassembly or cleaning procedures. This reduces maintenance downtime and allows rapid recovery of full chamber productivity.
Solution Approach 2:
The Faraday shield uses inexpensive materials and simple construction that allow it to be replaced frequently or disposed of after limited use, eliminating the need for complex cleaning or maintenance procedures and minimizing impact on wafer throughput.
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 Faraday shield effectively prevents deposition on the dielectric window, maintaining sufficient magnetic flux and plasma control, reducing ion energy and radial control issues, and enabling high aspect ratio feature etching with improved throughput and reduced cleaning downtime.
Implementation Method 1
maintaining plasma control and reduce capacitive coupling
Implementation Method 2
a chamber coil performs a function analogous to that of a primary coil in a transformer, while the plasma performs a function analogous to that of a secondary coil in the transformer
Implementation Method 3
maintaining the ability to transmit sufficient levels of magnetic flux to the plasma
Data Source
AI summary
Plasma processing chambers having internal Faraday shields with defined groove configurations, are defined. In one example, the chamber includes an electrostatic chuck for receiving a substrate and a dielectric window connected to a top portion of the chamber, where the dielectric window disposed over the electrostatic chuck. Also included is a Faraday shield disposed inside of the chamber and defined between the electrostatic chuck and the dielectric window. The Faraday shield includes an inner zone having an inner radius range, a middle zone having a middle radius range, an outer zone having an outer radius range, where the inner zone is adjacent to the middle zone, and the middle zone being adjacent to the outer zone. Further defining the Faraday shield is a first set of radial slots (A) extending through the inner zone, the middle zone, and the outer zone, a second set of radial slots (C) extending through only the outer zone; and a third set of radial slots (B) extending through the middle zone and outer zone. In this configuration, the first, second and third radial slots are arranged radially around the Faraday shield in a repeating pattern of slots A, C, B, and C.