CVD Preheat Ring Segmented Gap for Thermal Gradient Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In single-wafer thermal process chambers, the difference in emissivity between the wafer and susceptor rim leads to temperature gradients, causing crystalline defects like slip lines and nonuniform deposition, which existing systems cannot effectively control due to a fixed ring gap between the susceptor and preheat ring.
Innovation Solution
A preheat ring design with independently movable portions to form a tunable gap between the susceptor and the preheat ring, allowing for adjustable thermal coupling and reduced temperature gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed ring gap between the susceptor and preheat ring is used, then the device structure is simple, but the thermal gradient between the wafer edge and susceptor rim cannot be controlled, leading to slip lines and nonuniform deposition
Solution Approach 1:
The preheat ring is divided into multiple independently adjustable segments instead of a single fixed structure. Each segment can be positioned separately to control the gap size between the susceptor and preheat ring at different locations, enabling precise control of thermal gradients while maintaining a relatively simple overall device structure
Solution Approach 2:
The preheat ring transitions from a static fixed-gap structure to a dynamic adjustable-gap structure. The segments can be moved to change the gap size, allowing the system to adapt thermal conditions to different process requirements, thereby controlling temperature gradients and improving film uniformity
2Manufacturing precision
If heating elements and purge gas flows are adjusted to control the edge effect, then the temperature uniformity may be improved, but undesired effects occur elsewhere on the wafer
Solution Approach 1:
The preheat ring segments enable localized control of the thermal environment at the wafer edge without affecting other regions. By adjusting only the gap size at specific locations, the temperature gradient at the wafer edge can be controlled independently, avoiding the need to globally adjust heating elements or purge gas flows that would cause undesired effects elsewhere on the wafer
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 design enables precise control of the thermal gradient, reducing slip and achieving uniform film properties across the wafer by allowing independent adjustment of the gap size between the susceptor and preheat ring, thereby improving process tuning and reducing defects.
Implementation Method 1
The emissivity of the wafer and the susceptor rim can be different relative to one another, especially when one or more films are present on the wafer. The difference in emissivity can induce a substantial temperature gradient between the wafer edge and the susceptor rim.
Implementation Method 2
The gap between the susceptor and the preheat ring is an important parameter that influences both the gas flow and the thermal coupling between the ring and the susceptor.
Implementation Method 3
The gap between the susceptor and the preheat ring is an important parameter that influences both the gas flow and the thermal coupling between the ring and the susceptor.
Data Source
AI summary
A preheat ring (126) for use in a chemical vapor deposition system includes a first portion and a second portion selectively coupled to the first portion such that the first and second portions combine to form an opening configured to receive a susceptor therein. Each of the first and second portions is independently moveable with respect to each other.