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 inconsistent deposition layers and 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
1Device complexity
If uniform heat lamps are used across the substrate, then the manufacturing complexity is low, 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 each heat lamp. The central portion of each lamp has higher winding density to provide more heat to the center region of the substrate, while peripheral portions have lower winding density. This creates a non-uniform heat distribution pattern that compensates for the natural cooling at the substrate edges, achieving uniform temperature across the entire substrate surface.
2Temperature
If complex heating systems are used to achieve uniform temperature, then temperature uniformity is improved, but device complexity increases
Solution Approach 1:
The patent implements parameter changes by modifying the physical structure of the heat lamps themselves - specifically, the filament winding density parameter is varied along the length of each lamp. This structural parameter change creates inherent non-uniform heat output from each lamp, which when combined in an array, produces uniform temperature distribution across the substrate without requiring complex control systems or additional components.
3Use of energy by moving object
If radiant heating is used, then heating efficiency is improved, but temperature uniformity deteriorates due to localized heat sources
Solution Approach 1:
The patent maintains the efficiency of radiant heating while improving temperature uniformity by applying local quality to the heat lamp design. Each lamp in the array has a specific non-uniform heat output profile with higher intensity in the central portion and lower intensity at the ends. This localized variation in heat output across the array of radiant sources creates uniform temperature distribution while preserving the high efficiency of radiant heating technology.
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 deposition thickness uniformity across the substrate without requiring complex reengineering of the reaction chamber.
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
along with a parabolic reflector, to provide more controlled and uniform heating
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.