Bake Unit Purge Gas System for Substrate Temperature Uniformity
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Solution Overview
Problem
Existing bake units in semiconductor manufacturing face challenges in achieving uniform temperature and air flow above substrates due to uneven air flow supply, leading to issues with thickness uniformity and etch rate.
Innovation Solution
The proposed solution involves a bake unit with a housing, heater, heater cup, and purge gas supply units that block outside air inflow through gaps, using first and second purge gas supply units to maintain consistent temperature and air flow, and a baffle unit for processing gas distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the supply flow rate of processing gas is increased to raise an etch rate, then the etch rate is improved, but the air flow in the upper inner space of the chamber is supplied unevenly which worsens the unevenness of thickness uniformity
Solution Approach 1:
The gas supply system is segmented into multiple independent gas supply ports distributed across the chamber, allowing separate control of gas flow to different regions. This enables optimization of etch rate in high-density areas while maintaining uniformity in other areas, resolving the contradiction between overall etch rate and local thickness uniformity
Solution Approach 2:
Different regions of the chamber are provided with different gas supply characteristics through strategically positioned gas supply ports. Areas requiring higher etch rates receive increased gas flow, while areas sensitive to uniformity receive controlled flow, achieving both high productivity and manufacturing precision through localized quality control
2Manufacturing precision
If the supply flow rate of processing gas is decreased in order to resolve issues of unevenness in thickness uniformity, then the thickness uniformity is improved, but there is a rise of the inflow rate of outside air coming through a gap at the bottom side of lower portion of the chamber so the etch rate declines
Solution Approach 1:
A purge gas supply system is implemented to preemptively counteract the inflow of outside air through the bottom gap. By supplying purge gas at the bottom surface, the system prevents outside air from entering and disrupting the processing atmosphere, allowing maintenance of appropriate processing gas flow rates for both uniformity and etch rate
Solution Approach 2:
Purge gas acts as an intermediary substance that blocks the gap between the bottom surface and chamber wall, preventing outside air from entering the processing space. This intermediary gas flow maintains pressure balance and prevents harmful infiltration, enabling optimal processing conditions
3Device complexity
If the air flow supply structure is simplified to reduce device complexity, then the device complexity is reduced, but the air flow becomes unevenly supplied in the upper inner space of the chamber
Solution Approach 1:
The air flow supply is segmented into multiple distributed gas supply ports rather than a single centralized source. This segmentation creates multiple small-scale uniform flow zones that collectively provide even air flow distribution across the chamber, achieving uniformity without complex overall structure
Solution Approach 2:
The gas supply ports are designed to utilize the natural properties of gas flow and chamber geometry to achieve uniform distribution. The structure serves itself by leveraging pressure equalization and flow dynamics, eliminating the need for additional complex flow control mechanisms while maintaining air flow uniformity
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 configuration improves temperature uniformity and air flow above the substrate, maintains constant temperature, and enhances the etching rate by regulating the volume of purge gas supplied.
Implementation Method 1
a heater provided inside the heating plate, the substrate is heat treated by a heater provided inside the heating plate
Implementation Method 2
a first purge gas supply unit for supplying a first purge gas flow to block the inflow of outside air coming through a gap between the lower frame and the heater cup
Implementation Method 3
a baffle unit for spraying a processing gas onto the substrate placed on the heater
Data Source
AI summary
The inventive concept provides a bake unit. The bake unit comprising: a housing having an upper cover and a lower frame, the upper cover and the lower cover in combination providing a treatment space for heat treatment of a substrate; a heater provided in the treatment space for heating a substrate placed thereon; a heater cup configured to surround the heater; and a first purge gas supply unit for providing a first purge gas flow to block inflow of outer air through a gap between the lower frame and the heater cup.