Substrate Chamber Floor Geometry for Low-Shear Supercritical Drying
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Solution Overview
Problem
The challenge of pattern collapse or damage during supercritical drying processes in semiconductor wafers due to fluid turbulence is addressed.
Innovation Solution
A substrate processing apparatus with a specific container design and fluid supply system that includes an upper and lower container, support pins, and angled conduit lines to manage fluid flow and reduce shear stress on the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If supercritical fluid is used for drying semiconductor wafers, then cleaning and drying effectiveness is improved due to small surface tension, but pattern collapse or damage occurs due to fluid turbulence in some regions
Solution Approach 1:
The chamber lower surface is designed with different regions having different tilt angles. The first tilted surface has a first tilt angle, the second tilted surface has a second tilt angle different from the first, and the third tilted surface has a third tilt angle. This creates local variations in fluid flow characteristics across different regions of the chamber, allowing optimization of drying effectiveness in some areas while minimizing turbulence and pattern damage in other areas.
Solution Approach 2:
The chamber lower surface employs an asymmetric multi-region tilt design where each region (first, second, and third tilted surfaces) has a distinct tilt angle relative to the horizontal plane. This asymmetric configuration disrupts uniform fluid turbulence patterns and redistributes shear stress more evenly across the substrate, preventing localized pattern collapse while maintaining overall drying effectiveness.
2Productivity
If fluid pressure is increased to achieve supercritical state, then drying capability is improved, but turbulence and shear stress increase causing pattern damage
Solution Approach 1:
Different regions of the chamber lower surface have different tilt angles designed to locally control fluid flow characteristics. The first tilted surface, second tilted surface, and third tilted surface create varying flow patterns that reduce localized shear stress while maintaining the high pressure supercritical drying capability needed for effective drying.
Solution Approach 2:
The tilted surfaces convert the potentially harmful effect of high-pressure fluid flow into beneficial controlled turbulence. By designing specific tilt angles for different regions, the apparatus transforms what would be damaging shear stress into controlled fluid motion that enhances drying capability while protecting patterns from damage.
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 apparatus minimizes pattern damage by optimizing fluid flow distribution, reducing shear stress and vortex formation, thereby protecting delicate semiconductor patterns during drying.
Implementation Method 1
cleaning and drying methods using supercritical fluid with a relatively small surface tension are proposed
Implementation Method 2
supercritical fluid with a relatively small surface tension
Implementation Method 3
a chamber lower surface of the lower container, in contact with the processing space, includes a first surface, a first tilted surface, and a second surface extending sequentially from a center of the processing space
Implementation Method 4
patterns on substrates collapse or are damaged due to turbulence of the fluid in some regions of wafers
Data Source
AI summary
Provided is a substrate processing apparatus including a processing container including an upper container, a lower container, and a processing space formed inside the upper container and the lower container, support pins, a block plate having an upper surface on which the support pins are provided, a plate support provided in the lower container and configured to support a lower surface of the block plate, and a fluid supply device, wherein a chamber lower surface of the lower container in contact with the processing space includes a first surface, a first tilted surface, and a second surface extending sequentially from a center of the processing space, a vertical level of the second surface is higher than a vertical level of the first surface, and a first tilt angle formed between the first tilted surface and the first surface is an acute angle.