Nested Infrared Heating Zones for Wafer Temperature Uniformity
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Solution Overview
Problem
As wafer diameters increase, achieving temperature uniformity across the surface becomes challenging due to temperature differentials between the center and periphery, leading to varied etch rates and poor process uniformity in liquid treatment processes, with conventional solutions increasing costs and complexity or resulting in higher liquid consumption.
Innovation Solution
An apparatus with at least three individually controllable infrared heating elements arranged in a nested configuration to create inner, middle, and outer heating zones, allowing for precise temperature control across the disc-shaped article, with each element having a unique shape and position to heat regions at differing distances from the axis of rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heating methods are used, then temperature uniformity can be achieved, but device complexity and cost increase
Solution Approach 1:
The heating system is divided into multiple independent heating zones (inner, middle, outer zones) with individually controllable infrared heating elements. Each zone can be controlled separately to achieve uniform temperature distribution across the wafer surface without requiring complex centralized control systems.
Solution Approach 2:
Different regions of the wafer receive tailored heating through zone-specific control of infrared elements. The inner, middle, and outer heating zones can be independently adjusted to compensate for radial temperature gradients, providing localized temperature optimization without increasing overall device complexity.
2Temperature
If process liquid flow is increased to address temperature differentials, then temperature uniformity improves, but liquid consumption increases
Solution Approach 1:
The mechanical convection-based heating approach (relying on liquid flow to transport heat) is replaced with direct infrared radiation heating. This electromagnetic heating method directly heats the wafer and process liquid without requiring increased liquid flow, thereby maintaining temperature uniformity while reducing liquid consumption.
3Temperature
If high temperature liquid is dispensed to compensate for cooling, then temperature uniformity improves, but process control complexity increases
Solution Approach 1:
The process liquid is preheated before contacting the wafer surface through the spin chuck. This preliminary heating action ensures that the liquid starts at the desired temperature, eliminating the need for complex real-time temperature compensation controls during the treatment process.
Solution Approach 2:
The spin chuck acts as an intermediary heating element that transfers thermal energy from the infrared heating zones to the process liquid. This mediator approach simplifies control by using the chuck's rotation and thermal properties to distribute heat uniformly, rather than requiring complex liquid temperature regulation systems.
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 enhances process uniformity and control, achieving consistent etching profiles across the wafer surface with reduced liquid consumption and operational complexity, as demonstrated by the ability to invert etching profiles and optimize material removal at the center and periphery.
Implementation Method 1
at least three individually controllable infrared heating elements mounted above the upper surface of the spin chuck
Data Source
AI summary
An apparatus for treating a disc-shaped article comprises a spin chuck and at least three individually controllable infrared heating elements. The infrared heating elements are mounted in a stationary manner with respect to rotation of said spin chuck. The infrared heating elements are arranged in a nested configuration so as to define individually controllable inner, middle and outer heating zones adjacent a disc-shaped article when positioned on the spin chuck.