Semiconductor Lower Shield Thermal Management
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Solution Overview
Problem
Conventional semiconductor processing chambers face issues with sputtered material deposition on chamber components, thermal control of shields, and gas conductance, leading to contamination, plasma shorting, and reduced process uniformity due to poor thermal conductivity and increased temperature fluctuations.
Innovation Solution
A process kit comprising a lower shield, deposition ring, and cover ring designed to encircle the sputtering target and substrate support, with features such as cylindrical bands, support ledges, and v-shaped protuberances to reduce deposition on chamber walls, enhance thermal conductivity, and control temperature fluctuations, while the ring assembly and cover ring configuration improves gas conductance and prevents line-of-sight deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If shields are made of low thermal conductivity material, then thermal insulation is improved, but temperature control deteriorates causing excessive heating
Solution Approach 1:
The shield is divided into multiple segments or zones with different thermal properties. The shield comprises a first portion with low thermal conductivity for insulation and a second portion with high thermal conductivity for heat dissipation, allowing simultaneous thermal insulation and temperature control in different regions.
Solution Approach 2:
Different regions of the shield have different thermal conductivity properties tailored to their specific functions. The central region may have low thermal conductivity to insulate, while peripheral regions have high thermal conductivity to dissipate heat, creating local quality variations that resolve the contradiction.
2Reliability
If process kit components are designed to receive larger amounts of accumulated deposits, then deposition tolerance is improved, but cleaning complexity increases
Solution Approach 1:
The process kit components are designed as removable or detachable elements that can be easily extracted from the chamber. The shields and covers can be taken out as complete assemblies for cleaning, reducing cleaning complexity while maintaining high deposition tolerance through proper geometric design.
Solution Approach 2:
The process kit components are designed for periodic removal, cleaning, and reuse. The components can be discarded from the chamber as complete units, cleaned externally, and recovered for reuse, simplifying the cleaning process while allowing accumulation of large deposit amounts during operation.
3Temperature
If shields heat up to excessively high temperatures, then thermal radiation increases, but deposit adhesion deteriorates causing flaking
Solution Approach 1:
The shield design incorporates features that prevent excessive heating before it occurs. Thermal management features such as heat sinks, cooling channels, or thermally conductive pathways are built into the shield structure in advance to counteract temperature rise and prevent the condition that would lead to deposit flaking.
Solution Approach 2:
The shield is constructed from composite materials or material combinations that provide both the desired thermal radiation properties and sufficient thermal management. The composite structure allows controlled thermal behavior that maintains deposit adhesion while achieving necessary thermal radiation for the process.
4Object-affected harmful factors
If chamber components are designed to reduce sputter deposits, then contamination is reduced, but manufacturing complexity increases
Solution Approach 1:
Multiple functions are merged into single process kit components. The shields and covers simultaneously serve as deposition barriers, thermal management elements, and mechanical support structures. This integration reduces the number of separate parts needed, lowering manufacturing complexity while maintaining contamination reduction capabilities.
Solution Approach 2:
The process kit components are designed with universal multi-functionality, where each component performs multiple roles: protecting against sputter deposits, managing thermal loads, providing mechanical support, and facilitating easy installation/removal. This multi-functionality reduces the overall number of components needed, simplifying manufacturing.
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 process kit reduces RF harmonics and stray plasma, promoting greater process uniformity, longer chamber component life, and easier cleaning by minimizing sputter deposits and maintaining stable temperatures, thereby enhancing the overall efficiency and reliability of semiconductor processing.
Implementation Method 1
designed to receive and tolerate ever larger amounts of accumulated deposits without sticking to each other or to the substrate, or resulting in flaking off of the deposits between process clean cycles
Implementation Method 2
it is difficult to control the temperature of shields made of low thermal conductivity material. The thermal resistances at contact interfaces with supporting components, such as adapters, also affect shield temperatures
Implementation Method 3
In PVD chambers, a target is sputtered by energized gas to sputter target material which then deposits on the substrate facing the target
Implementation Method 4
Another problem arises when the chamber liners and shields heat up to excessively high temperatures due to exposure to the sputtering plasma in the chamber
Data Source
AI summary
Embodiments described herein generally relate to components for a semiconductor processing chamber, a process kit for a semiconductor processing chamber, and a semiconductor processing chamber having a process kit. In one embodiment a lower shield for encircling a sputtering target and a substrate support is provided. The lower shield comprises a cylindrical outer band having a first diameter dimensioned to encircle the sputtering surface of the sputtering target and the substrate support, the cylindrical band comprising a top wall that surrounds a sputtering surface of a sputtering target and a bottom wall that surrounds the substrate support, a support ledge comprising a resting surface and extending radially outward from the cylindrical outer band, a base plate extending radially inward from the bottom wall of the cylindrical band, and a cylindrical inner band coupled with the base plate and partially surrounding a peripheral edge of the substrate support.