Conductance Control for Uniform Substrate Temperature
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Solution Overview
Problem
Chemical deposition processes in semiconductor fabrication face challenges with nonuniform temperatures across substrates due to passive heating showerheads losing heat to surrounding chamber components, leading to nonuniform processing.
Innovation Solution
A chemical deposition apparatus with a flush mount showerhead and conductance control assemblies, such as ball valves, fluidic valves, rotary valves, and magnetically coupled linear valves, to regulate chamber pressure and flow, ensuring uniform temperature and isothermal processing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a passive heating showerhead is used, then the substrate is heated, but heat is lost to surrounding chamber components causing nonuniform temperatures
Solution Approach 1:
The patent introduces an isothermal processing zone as an intermediary environment between the showerhead and substrate. This zone acts as a thermal mediator that distributes heat uniformly across the substrate surface while preventing heat loss to surrounding chamber components, thereby resolving the contradiction between heating the substrate and maintaining temperature uniformity.
Solution Approach 2:
The patent extracts the substrate from the general chamber environment and places it within a dedicated isothermal processing zone. This separation isolates the substrate from harmful thermal interactions with surrounding chamber components, allowing independent temperature control and uniform heat distribution without being affected by external heat losses.
2Temperature
If conductance control assemblies are added to regulate chamber pressure and flow, then uniform temperature and isothermal processing conditions are achieved, but device complexity increases
Solution Approach 1:
The conductance control assemblies are designed to perform multiple functions simultaneously: they regulate chamber pressure, control gas flow rates, maintain isothermal conditions, and enable rapid pressure changes for purging. By consolidating these functions into integrated assemblies, the patent reduces overall device complexity while achieving uniform temperature control and isothermal processing conditions.
Solution Approach 2:
The conductance control assemblies are configured to automatically maintain isothermal processing conditions through self-regulating mechanisms. The assemblies respond to pressure and flow changes autonomously, adjusting conductance to preserve temperature uniformity without requiring external intervention, thereby simplifying the control system while ensuring consistent processing conditions.
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 solution achieves uniform substrate temperatures, enhancing the uniformity of the deposition process and improving the control of deposition reactions by maintaining an isothermal processing zone, thereby improving the quality of semiconductor fabrication.
Implementation Method 1
allow the reactor chemistries and a purge gas to flow from the cavity into one or more evacuation vacuum lines upon exceeding a first pressure and flow rate within the cavity
Implementation Method 2
the stream of modulating gas modulates flow resistance experienced by the flow of the reactor chemistries from the cavity
Implementation Method 3
a plurality of linear rods, which are configured to be magnetically raised and lower within a plurality of channels, each of the plurality of linear rods having a proximal portion, which is configured to be magnetically coupled to the magnetic housing
Data Source
AI summary
A chemical deposition apparatus having conductance control, which includes a showerhead module having a faceplate and a backing plate, the showerhead module including a plurality of inlets which deliver reactor chemistries to a cavity and exhaust outlets which remove reactor chemistries, a pedestal module configured to support a substrate and which moves vertically to close the cavity between the pedestal module and an outer portion of the faceplate, and at least one conductance control assembly, which is in fluid communication with the cavity via the exhaust outlets. The at least one conductance control assembly selected from one or more of the following: a ball valve assembly, a fluidic valve, magnetically coupled rotary plates, and/or a linear based magnetic system.