Showerhead Plenum Layout for Simultaneous Epitaxy and Etch-Back
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Solution Overview
Problem
Existing epitaxial deposition processes face challenges with untargeted nodule formation and uneven growth rates on high aspect ratio structures, leading to interference and reduced throughput due to the need for alternate etch-back processes between deposition and etch chambers.
Innovation Solution
A processing chamber and method that integrates a deposition zone and an etch zone within a common volume, utilizing separate plenums for deposition and etchant gases, with a showerhead design that includes a separation section to prevent gas mixing and a connecting section with conduits for directional etching, allowing simultaneous deposition and etching on rotating substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alternate etch-back process is used between deposition and etch chambers, then isolated nodules can be removed from non-targeted surfaces, but substrate transfer between chambers lowers throughput
Solution Approach 1:
The patent combines the deposition chamber and etch chamber into a single integrated processing chamber. The showerhead is divided into a deposition zone and an etch zone, allowing both deposition and etching processes to occur simultaneously in different spatial regions without requiring substrate transfer between separate chambers, thereby maintaining high throughput while ensuring reliable nodule removal.
Solution Approach 2:
The showerhead is segmented into distinct functional zones: a deposition zone for material deposition and an etch zone for removing nodules. This spatial segmentation allows independent control of deposition and etching processes, enabling simultaneous operation without interference between the two processes.
2Manufacturing precision
If EPI growth is performed on structures of high aspect ratios, then material can be deposited onto fins or deep trenches, but untargeted locations experience isolated nodule formation that interferes with subsequent processes
Solution Approach 1:
The showerhead design provides local quality by directing deposition gas preferentially toward targeted locations (fins or deep trenches) while the etch zone simultaneously treats untargeted locations. This localized control allows precise material deposition where needed while removing nodules where not needed, achieving uniform manufacturing quality across different regions.
Solution Approach 2:
The etch zone acts as an intermediary mechanism that counteracts the harmful nodule formation effect. By introducing the etch zone as a mediator, the system can selectively remove nodules from untargeted surfaces while preserving the deposition process on targeted structures, thus eliminating the harmful side effect without compromising the primary deposition function.
3Productivity
If deposition gas flows laterally to a plenum between showerhead and susceptor, then deposition can occur on substrate, but gas mixing with etchant gas may occur without proper separation
Solution Approach 1:
The showerhead is segmented into a deposition zone and an etch zone with distinct gas flow paths. The deposition gas flows laterally to a plenum in the deposition zone, while etchant gas is supplied separately to the etch zone. This segmentation prevents gas mixing while enabling simultaneous operation of both processes, maintaining both productivity and gas composition stability.
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
Enables simultaneous deposition and etching processes without substrate transfer, improving throughput and preventing nodule formation by ensuring uniform growth on high aspect ratio structures.
Implementation Method 1
Epitaxy (EPI) has been widely used in depositing materials on surfaces of semiconductor substrates and devices
Implementation Method 2
An etch-back process may be implemented, which adds an etch process during the deposition process to remove any isolated nodules from non-targeted surfaces
Data Source
AI summary
Disclosed herewith are a showerhead, a processing chamber, and a method for growing an epitaxial layer. A body of the showerhead has a disk-shape. The body includes a separation section formed by a solid circular sector and a connecting section formed by another circular sector that have a plurality of conduits. The connecting section and the separation section are coplanar and non-overlapping. The processing chamber includes the showerhead, a first gas inlet configured to flow a deposition gas in a lateral direction to a first plenum under the showerhead; and a second gas inlet configured to flow an etchant gas to a second plenum above the showerhead. The plurality of conduits allow the etchant gas to flow in a direction from the first plenum to the second plenum. The method can simultaneously implement both a deposition process and an etching process in the processing chamber.