Linear Heat Lamp Layout for Uniform Wafer Temperature
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Solution Overview
Problem
Semiconductor processing systems face challenges in achieving uniform temperature distribution across substrates due to non-uniform heat output from radiant heating methods, leading to 'hot spots' and 'cold spots' which result in processing nonuniformities and inconsistent device performance.
Innovation Solution
A semiconductor processing system with a top array of linear heat lamps having varying power output across their length, with higher power in the central portion and lower power in peripheral portions, and a bottom array of linear heat lamps, along with a parabolic reflector, to provide more controlled and uniform heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If radiant heating with infrared lamps is used to heat substrates efficiently, then heating efficiency is improved, but temperature uniformity deteriorates due to hot spots and cold spots
Solution Approach 1:
The patent applies local quality by varying the filament winding density along the length of the heating lamps. The central portion of the lamps has higher winding density to generate more heat, while the peripheral portions have lower winding density to generate less heat. This non-uniform filament structure creates a tailored heat distribution pattern that compensates for the natural cooling effects at the substrate edges, thereby improving temperature uniformity across the substrate surface while maintaining high heating efficiency.
2Manufacturing precision
If uniform temperature distribution is achieved across the substrate, then deposition uniformity is improved, but heating system complexity increases
Solution Approach 1:
The patent implements local quality through non-uniform filament winding density in the heating lamps. By concentrating more filament windings in the central region and fewer in the peripheral regions, the system achieves uniform temperature distribution across the substrate without requiring complex multi-zone control systems or multiple independent heating elements. This approach simplifies the overall heating system architecture while maintaining high deposition uniformity.
3Temperature
If heat is concentrated in the central portion of the substrate, then cold spots are reduced, but risk of creating new hot spots increases
Solution Approach 1:
The patent carefully applies local quality by creating a gradient in filament winding density rather than a abrupt concentration. The central portion has higher winding density to address cold spots, while the peripheral portions have progressively lower density to prevent overheating. This gradual transition in heat generation capacity balances the thermal distribution, reducing cold spots without creating harmful hot spots in the peripheral regions.
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 configuration effectively addresses temperature nonuniformities by concentrating heat in the central portion, reducing 'cold spots' and enhancing temperature uniformity, resulting in more consistent deposition thickness and electrical properties across the substrate.
Implementation Method 1
at least one lamp of the top array of linear heat lamps configured to provide a power output, the power output varying across a length of the at least one lamp
Implementation Method 2
radiant heating involves positioning infrared lamps within high-temperature ovens, called reactors (or reaction chambers) within which substrates are processed
Data Source
AI summary
An arrangement of linear heat lamps is provided which allows for localized control of temperature nonuniformities in a substrate during semiconductor processing. A reactor includes a substrate holder positioned between a top array and a bottom array of linear heat lamps. At least one lamp of the arrays includes a filament having a varying density and power output along the length of the lamp. In particular, at least one lamp of the arrays includes a filament having a higher filament winding density within a central portion of the lamp relative to peripheral portions of the lamp. In some embodiments, the at least one lamp is a central lamp extending across a central portion of the substrate heated by the lamp. Furthermore, at least one lamp of the arrays has a higher power output within a central portion of the lamp than at peripheral portions of the lamp.