Wafer Temperature Control via Segmented Heating Zones
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Solution Overview
Problem
Current heating apparatuses for plasma enhanced processing, such as chuck heaters, struggle to achieve uniform wafer temperature, leading to center-edge differences in plasma density, chemical reaction rates, and etch rates, resulting in inconsistent critical dimensions and low production yields due to process drifts and variability.
Innovation Solution
A novel heating apparatus with a plurality of temperature control elements, each configured to individually control temperature across different portions of the wafer, allowing for per-site temperature tuning to address center-edge differences and improve wafer uniformity, using heating, cooling, and sensing elements, and a processor to determine and adjust temperatures for uniformity control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a chuck heater with outer and inner annular capacitors is used to heat different zones of the wafer, then the wafer can be heated in plasma enhanced processing, but center-edge difference on wafer temperature is induced, leading to non-uniform plasma density and etch rate
Solution Approach 1:
The heater is divided into multiple independent heating zones (outer annular capacitor, inner annular capacitor, and additional intermediate capacitors) that can be controlled separately. This segmentation allows independent temperature control of different wafer regions to compensate for center-edge temperature differences and achieve uniform plasma processing conditions across the entire wafer surface
Solution Approach 2:
Different heating power levels are applied to different spatial zones of the wafer based on their specific thermal requirements. The outer zones receive different heating intensity compared to the center zone, allowing local optimization of temperature distribution to eliminate center-edge temperature gradients and improve overall wafer uniformity
2Device complexity
If traditional zone-based heating is used, then the heating apparatus structure is simple, but the wafer surface temperature is only tunable by zone, making it hard to control wafer uniformity
Solution Approach 1:
The heating apparatus is segmented into multiple independently controllable capacitor zones, transforming a simple single-zone heater into a multi-zone system. This segmentation enables precise temperature control at different locations on the wafer surface, allowing fine-tuning of temperature distribution to achieve uniform plasma processing while maintaining a relatively straightforward capacitive heater structure
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 enables precise control of wafer surface temperature by site, improving uniformity during plasma enhanced processing, reducing die-to-die performance variations, and enhancing production yields by minimizing plasma density and chemical reaction rate variations across the wafer.
Implementation Method 1
Each of the temperature control elements is configured to individually control temperature of a corresponding portion of the wafer
Implementation Method 2
using heating, cooling, and sensing elements
Implementation Method 3
A novel heating apparatus with a plurality of temperature control elements, each configured to individually control temperature across different portions of the wafer
Implementation Method 4
Plasma enhanced processing techniques have gained widespread use in fabrication of devices for various applications
Data Source
AI summary
An apparatus for controlling wafer uniformity is disclosed. In one example, the apparatus includes: a plurality of temperature control elements and a processor. Each of the temperature control elements corresponds to a different portion of a wafer respectively such that the temperature control elements correspond to different portions of the wafer. Each of the temperature control elements is configured to individually control temperature of a corresponding portion of the wafer. The processor determines at least one portion of the wafer for temperature uniformity control, and instruct at least one of the temperature control elements, corresponding to the at least one portion, to adjust temperature of the at least one portion for controlling temperature uniformity of the wafer.