UV Reflector Coating Layout for Uniform Wafer Curing
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Solution Overview
Problem
Existing UV curing technologies for semiconductor wafers face issues with non-uniform UV intensity distribution, leading to film shrinkage and performance variability, particularly on larger wafer sizes.
Innovation Solution
A UV curing apparatus with a window featuring UV radiation modifiers, such as diverging lenses or UV absorbing coatings, and reflectors with non-uniform reflective coatings, to achieve uniform UV irradiation across the wafer surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional UV curing technology is used, then the curing process is simple, but the UV intensity distribution is non-uniform causing film shrinkage and performance variability
Solution Approach 1:
The patent applies local quality by using UV radiation modifiers (diverging lenses or absorbing coatings) at specific locations where UV intensity is excessive, and non-uniform reflective coatings on reflectors to selectively adjust UV distribution. This targeted approach achieves uniform curing across the wafer surface without requiring complete redesign of the entire curing system.
Solution Approach 2:
The patent introduces UV radiation modifiers and non-uniform reflective coatings as intermediary elements between the UV light source and the wafer surface. These intermediaries actively regulate UV intensity distribution, converting the non-uniform output into uniform irradiation across the wafer, thereby resolving the contradiction between simplicity and precision.
2Productivity
If UV intensity is increased to improve curing efficiency, then productivity increases, but hot spots are created causing film shrinkage and defects
Solution Approach 1:
The patent converts the harmful concentrated UV intensity into a beneficial uniform distribution by using UV radiation modifiers and non-uniform reflective coatings. These components redirect excess UV energy from high-intensity regions to low-intensity regions, transforming potential defects into effective curing while maintaining high overall productivity.
Solution Approach 2:
The patent changes the spatial distribution parameter of UV intensity by introducing modifiers and non-uniform coatings. This parameter transformation allows the system to operate at high overall intensity levels for productivity while maintaining local uniformity to prevent hot spots and film shrinkage.
3Productivity
If wafer size is increased to improve manufacturing capacity, then productivity increases, but UV uniformity deteriorates leading to greater performance variability
Solution Approach 1:
The patent applies local quality adjustments through UV radiation modifiers and non-uniform reflective coatings that are specifically designed for larger wafer dimensions. These components create localized UV intensity adjustments that compensate for the increased wafer area, maintaining uniform curing across the entire surface despite the larger size.
Solution Approach 2:
The patent addresses the two-dimensional challenge of large wafer surface uniformity by introducing elements that operate in the optical path dimension. The UV radiation modifiers and non-uniform coatings manipulate UV distribution in the spatial dimension, enabling uniform curing across extended wafer areas without compromising manufacturing capacity.
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
Ensures uniform UV curing intensity, minimizing film shrinkage and enhancing device yield by preventing high-intensity 'hot spots', thereby improving the consistency of semiconductor performance.
Implementation Method 1
a UV reflective coating on a surface of the reflector that faces the UV lamp. The UV reflective coating includes a plurality of zones with different UV reflectances
Implementation Method 2
a UV absorbing coating on a surface of the window that faces the UV lamp. The UV absorbing coating includes a plurality of zones with different UV absorbances
Implementation Method 3
A UV curing apparatus with a window featuring UV radiation modifiers, such as diverging lenses or UV absorbing coatings
Data Source
AI summary
An ultraviolet (UV) lamp assembly of a UV curing tool is provided for curing a low dielectric constant (low-k) material layer of a semiconductor wafer. The UV lamp assembly includes: a UV lamp which emits UV light; a first reflector arranged proximate to a first side of the UV lamp, the first reflector including a first surface facing the UV lamp from which UV light emitted by the UV lamp is at least partially reflected; and a UV reflective coating partially coating the first surface of the reflector. Suitably, a plurality of areas of the first surface of the reflector remain uncoated with the UV reflective coating and the plurality of uncoated areas are arranged to promote a uniform exposure of the semiconductor wafer to UV irradiation.