Perforated Substrate Support for Backside Accretion Control
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Solution Overview
Problem
Existing semiconductor processing systems face challenges with accretion formation during material layer deposition, which can impair temperature control, mechanical reliability, and cause damage to components, due to the deposition of material layer precursors and reaction products on chamber walls and substrate supports.
Innovation Solution
A substrate support design featuring a disc body with a circular concavity, annular ledge, and annular rim, including perforated and unperforated portions, allows for controlled etchant flow to prevent accretion formation by fluidly coupling the etchant into a cavity between the substrate and the support, while minimizing etchant exposure to the substrate's backside.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If etchant is provided to reaction chamber to etch surfaces and structures prone to accretion development, then accretion formation is reduced, but damage to reaction chamber and substrate may occur
Solution Approach 1:
The substrate support structure incorporates a perforated portion and unperforated portion with distinct functions: the perforated portion allows etchant to pass through to prevent accretion on the substrate backside, while the unperforated portion blocks etchant from reaching and damaging the substrate. This spatial differentiation of etchant permeability enables localized accretion prevention without causing substrate damage.
Solution Approach 2:
The concavity of the substrate support is divided into functionally distinct segments: a perforated portion for etchant transmission and an unperforated portion for etchant blocking. This segmentation allows the single substrate support structure to simultaneously perform multiple functions: preventing accretion where needed while protecting the substrate from harmful etchant exposure.
2Reliability
If flow of material layer precursor is adjusted to limit accretion development, then accretion on interior surfaces is reduced, but material layer thickness profile control is compromised
Solution Approach 1:
The substrate support concavity is segmented into perforated and unperforated portions that work together to prevent accretion on the substrate backside without requiring flow adjustments that would compromise material layer thickness profile control on the substrate front side.
Solution Approach 2:
The perforated portion of the substrate support acts as an intermediary structure that allows controlled passage of etchant to the substrate backside region, enabling accretion prevention in that specific zone without affecting the precursor flow and deposition process on the substrate front side where thickness profile control occurs.
3Reliability
If purge gas is provided to separate material layer precursor from interior surfaces, then accretion development is limited, but purge efficacy is reduced by precursor diffusion into purge gas
Solution Approach 1:
Instead of using purge gas to remove precursor, the invention extracts the accretion-prone environment by providing etchant directly to the substrate backside region through the perforated support structure, preventing accretion at its source without requiring bulk purge gas flow that would suffer from diffusion losses.
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 effectively limits accretion formation on chamber walls and substrate supports, enhancing temperature control and mechanical reliability, and reducing the risk of substrate damage during material layer deposition.
Implementation Method 1
The perforated portion extends and has a plurality of perforations to issue an etchant into a cavity defined between the upper surface of the substrate support and a backside of a substrate seated on the substrate support
Implementation Method 2
The unperforated portion extends circumferentially about the perforated portion to axially space the etchant issued into the cavity from the backside of the substrate
Implementation Method 3
an etchant may be provided to reaction chamber to etch surfaces and structures prone to accretion development
Data Source
AI summary
A substrate support includes a disc body with upper and lower surfaces spaced apart by a thickness. The upper surface has a circular concavity extending about a rotation axis, an annular ledge portion radially outward of the concavity extending circumferentially about the concavity, and an annular rim portion radially outward of the ledge portion extending circumferentially about the ledge portion. The concavity has a circular perforated portion and an annular unperforated portion. The perforated portion extends about the rotation axis and defines two or more perforations to issue an etchant into a cavity defined between the concavity and a backside of a substrate seated on the substrate support. The unperforated portion is radially outward of the perforated portion and extends circumferentially about the perforated portion to limit etching of the backside of the substrate by the etchant. Semiconductor processing systems and material layer deposition methods are also described.