Wafer Support Surface Adjustment for Uniform Etching Temperature
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Solution Overview
Problem
Semiconductor wafers with non-linear backside surfaces, such as bowing or warping, pose challenges during etching processes due to non-uniform temperature application, leading to compromised critical dimensions and rejection of processed wafers.
Innovation Solution
A substrate support apparatus with independently movable support elements and a thermal energy transfer device, which adjusts its surface to match the non-linear backside surface of the wafer, ensuring uniform temperature distribution and energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If vacuum is applied to pull the wafer into contact with the hot plate, then the wafer surface becomes flat, but air flow is generated causing non-uniform temperature distribution
Solution Approach 1:
A flexible membrane is introduced as an intermediary between the vacuum source and the wafer surface. The membrane transmits the vacuum force to flatten the wafer while its flexible nature allows it to conform to the wafer's non-linear surface, preventing direct air flow gaps that would cause non-uniform temperature distribution during heating.
Solution Approach 2:
The patent employs a flexible membrane (thin film) that can adapt its shape to match the non-linear surface of the wafer. This flexible film maintains intimate contact with the wafer surface under vacuum, eliminating air gaps that would otherwise lead to non-uniform thermal contact and temperature distribution during the heating process.
2Shape
If increased vacuum force is applied to pull a wafer with large bow to a hot plate, then the wafer contacts the hot plate surface, but non-uniform baking/curing of the resistive film increases
Solution Approach 1:
The flexible membrane serves as a mediator that distributes the vacuum force uniformly across the wafer surface, including areas with large bow. This prevents localized high vacuum forces that would press the wafer unevenly against the hot plate, thereby ensuring uniform thermal contact and consistent baking/curing of the resistive film across the entire wafer surface.
Solution Approach 2:
The patent changes the physical state and properties of the membrane from rigid to flexible, allowing it to dynamically adapt its shape and conform to varying wafer surface topographies. This parameter change enables the system to handle wafers with large bow while maintaining uniform contact pressure and thermal distribution during heating processes.
3Ease of manufacture
If a flat hot plate surface is used, then manufacturing is simple, but it cannot match the non-linear backside surface of the wafer for uniform thermal contact
Solution Approach 1:
Instead of manufacturing a complex non-linear hot plate surface, the patent uses a flexible membrane that can be easily manufactured in a simple flat or slightly curved form. The membrane's flexibility allows it to conform to the wafer's non-linear surface during operation, achieving uniform thermal contact without requiring complex manufacturing processes for the hot plate itself.
Solution Approach 2:
The patent transitions from a static, rigid hot plate surface to a dynamic, flexible membrane system. The membrane can dynamically adjust its shape in response to the wafer's surface topology and vacuum pressure, enabling uniform thermal contact across non-linear wafer surfaces while keeping the hot plate structure simple and easy to manufacture.
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 solution maintains critical dimensions of patterned structures by providing uniform thermal energy transfer to the wafer, reducing the risk of wafer rejection and improving etching process outcomes.
Implementation Method 1
an actuator system operably coupled to each of the mutually lateral support elements to selectively move one or more of the mutually lateral support elements vertically
Implementation Method 2
a thermal energy transfer device operably coupled to each of the support elements
Data Source
AI summary
Systems, method and related apparatuses for adjusting support elements of a support apparatus to approximate a surface profile of a wafer. The support apparatus may include a group of mutually lateral adjacent support elements, each mutually lateral adjacent support element is configured to independently move at least vertically and comprising an upper surface. The support apparatus may further include a thermal energy transfer device operably coupled to each of the mutually lateral support elements, and an actuator system operably coupled to each of the support elements to selectively move one or more of the mutually lateral support elements vertically.