Segmented Showerhead Heating for Wafer Edge Temperature Uniformity
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Solution Overview
Problem
Current semiconductor processing chamber technologies suffer from significant temperature non-uniformity across wafers, particularly in peripheral regions, due to inefficient heating distribution, leading to suboptimal film quality and non-compliance with stringent manufacturing requirements.
Innovation Solution
A processing chamber lid with a showerhead heater and gas funnel, featuring individually controlled heater segments on the showerhead to directly heat the peripheral region of the wafer, minimizing temperature non-uniformity by adjusting the substrate support heater and showerhead heaters independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a central heater is used to heat the substrate from below, then the center of the wafer is heated effectively, but the peripheral region experiences temperature non-uniformity and heat loss
Solution Approach 1:
The heating system is segmented into multiple independent heating zones: a central substrate support heater and multiple showerhead heater segments positioned at different radial locations. This segmentation allows independent temperature control of different regions to achieve uniform wafer temperature while compensating for peripheral heat losses through targeted heating zones near gas inlet/outlet openings.
Solution Approach 2:
Different heating strategies are applied to different regions: the central substrate support provides base heating, while additional showerhead heater segments are strategically positioned near peripheral openings where heat loss occurs. This local quality approach ensures that each region receives appropriate heating to maintain overall temperature uniformity across the wafer surface.
2Productivity
If gas flow is increased for process requirements, then processing efficiency improves, but temperature non-uniformity increases due to enhanced cooling effect at wafer periphery
Solution Approach 1:
The showerhead heater segments are positioned upstream near gas inlet openings to preemptively counteract the cooling effect of incoming cold process gas. By heating the showerhead and gas flow path before the gas reaches the wafer periphery, the system prevents temperature non-uniformity from developing, allowing high gas flow rates to be used without compromising temperature uniformity.
Solution Approach 2:
Additional heating is applied locally at the showerhead periphery where cold gas enters and where temperature non-uniformity develops most severely. This localized heating compensates for the enhanced cooling effect of high gas flow rates, maintaining uniform wafer temperature even at high processing efficiencies.
3Device complexity
If a single exhaust port or slit valve is used for wafer transport, then device complexity is reduced, but temperature non-uniformity increases due to pronounced temperature loss at these openings
Solution Approach 1:
The chamber maintains its simple single exhaust port or slit valve structure, but adds localized showerhead heater segments positioned near these openings. This approach preserves device simplicity while compensating for temperature losses at the openings through targeted heating, maintaining temperature uniformity without increasing overall structural complexity.
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 effectively reduces temperature non-uniformity to less than 3°C across the wafer, enhancing film quality and meeting stringent manufacturing standards by ensuring uniform heat distribution and minimizing heat loss.
Implementation Method 1
The showerhead heater is positioned on the back surface of the showerhead
Implementation Method 2
a wafer is typically heated from below by a heater within a substrate support
Data Source
AI summary
Process chamber lids, processing chambers and methods using the lids are described. In some embodiments, the lid includes a showerhead with a plurality of heater segments in a peripheral region thereof. The heated showerhead minimizes temperature non-uniformity and/or minimizes heat less near the peripheral edge of a processed wafer.