Wafer Edge Heating Layout for Flatness During Wet Etching
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Solution Overview
Problem
Conventional semiconductor manufacturing processes face challenges in efficiently heating the peripheral portions of substrates during wet etching, which can lead to inefficiencies and difficulties in maintaining substrate flatness, especially with thinner and larger diameter substrates.
Innovation Solution
A substrate processing apparatus featuring a heating device with multiple fins arranged along the circumferential direction under the substrate, a heat source to heat the fins, and a fluid introduction and discharge unit to supply heated fluid efficiently to the substrate's peripheral portion, enhancing heating efficiency and allowing for compact design to fit in narrow spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional heating device is used to heat the peripheral portion of the substrate, then the substrate can be heated during wet etching, but the heating efficiency is insufficient and the device occupies a large space
Solution Approach 1:
The heating device is divided into multiple independent heating elements arranged in the circumferential direction. Each heating element can be independently controlled and positioned, allowing the heating function to be distributed across multiple small units rather than requiring a single large heating device, thus improving heating efficiency while reducing overall device space
Solution Approach 2:
The heating elements are arranged in the circumferential direction (tangential to the substrate) rather than radially or axially. This circumferential arrangement allows the heating device to fit in a narrow radial space while still effectively heating the peripheral portion of the substrate through the chemical liquid, resolving the space efficiency problem
2Area of moving object
If the substrate diameter is increased to accommodate larger wafers, then more substrates can be processed, but maintaining substrate flatness becomes more difficult
Solution Approach 1:
Heating is applied locally to the peripheral portion of the substrate rather than uniformly across the entire substrate surface. This localized heating at the edges helps maintain substrate flatness by preventing warping that would occur with uniform heating, while still enabling effective wet etching of the peripheral regions where it is most needed
Solution Approach 2:
The heating device is designed to work in conjunction with substrate rotation. The rotating substrate dynamically exposes different peripheral regions to the heating elements sequentially, ensuring uniform heating around the entire periphery while maintaining flatness through continuous motion and localized thermal treatment
3Productivity
If heating is applied to the peripheral portion of the substrate, then etching efficiency is improved, but it becomes difficult to maintain uniform temperature distribution
Solution Approach 1:
The heating function is segmented into multiple heating elements distributed circumferentially around the substrate periphery. This segmentation allows each heating element to target specific regions, and through coordinated operation of multiple elements, achieve both high etching efficiency at the periphery and uniform temperature distribution around the entire substrate edge
Solution Approach 2:
The heating elements operate continuously during the wet etching process, maintaining constant thermal input to the peripheral portion of the substrate. This continuous heating, combined with substrate rotation, ensures uniform temperature distribution is maintained throughout the etching process, preventing thermal gradients that would compromise temperature 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
The apparatus achieves efficient heating of the substrate's peripheral portion, enabling faster etching processes while maintaining substrate flatness and allowing for a scalable design that fits within constrained spaces, even with larger diameter substrates.
Implementation Method 1
The heat source heats the multiple fins
Implementation Method 2
The fluid discharge unit discharges the fluid, which is heated while passing through the multiple fins, to the bottom surface of the substrate
Data Source
AI summary
A substrate processing apparatus includes a holder and a heating device. The holder is configured to hold a central portion of a bottom surface of a substrate to be rotated. The heating device is configured to supply a heated fluid to the bottom surface of the substrate. The heating device includes multiple fins, a heat source, a fluid introduction unit and a fluid discharge unit. The multiple fins are arranged along a circumferential direction of the substrate to be located under the substrate at an outer side than the holder. The heat source is configured to heat the multiple fins. The fluid introduction unit is configured to introduce the fluid to the multiple fins. The fluid discharge unit is configured to discharge the fluid, which is heated while passing through the multiple fins, to the bottom surface of the substrate.