UV Reflector Coating Layout for Uniform Wafer Curing
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Solution Overview
Problem
Existing UV curing technologies for semiconductor wafers often result in non-uniform UV irradiation, leading to film shrinkage and performance variability, particularly in larger wafers, due to uneven UV intensity distribution.
Innovation Solution
A UV curing tool with a process chamber and UV light source configuration that includes a window with a UV radiation modifier, such as diverging lenses or UV light absorbing coatings, to ensure uniform UV irradiation across the wafer surface, minimizing high-intensity 'hot spots' and promoting even curing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional UV curing technology is used, then the curing process is simple and fast, but the UV irradiation is non-uniform causing film shrinkage and performance variability
Solution Approach 1:
A UV radiation modifier is introduced as an intermediary component between the UV light source and the wafer. This modifier actively adjusts the UV radiation distribution to achieve uniform irradiation across the wafer surface, resolving the contradiction by adding a mediating element that corrects the non-uniformity without requiring complete system redesign
Solution Approach 2:
The UV radiation modifier applies different properties to different regions of the UV beam path. By creating zone-dependent refraction or absorption characteristics within the modifier, the system achieves uniform UV distribution across the wafer surface while maintaining a relatively simple overall structure
2Productivity
If UV intensity is increased to improve curing speed, then productivity increases, but hot spots are created causing film shrinkage and defects
Solution Approach 1:
The UV radiation modifier converts the potentially harmful concentrated UV intensity into a beneficial uniform distribution. By using refraction or absorption mechanisms, the modifier transforms high-intensity hot spots into evenly distributed UV radiation, allowing high productivity without the harmful effects of concentration
Solution Approach 2:
The system changes the spatial distribution parameters of UV radiation through the modifier. By adjusting the refraction angles or absorption characteristics in different zones of the modifier, the UV intensity parameters are transformed from a concentrated pattern to a uniform pattern across the wafer surface
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
The solution achieves uniform UV curing intensity, reducing film shrinkage and enhancing the thickness uniformity of low-k material thin films, thereby improving semiconductor device performance and yield.
Implementation Method 1
a window with a UV radiation modifier, such as diverging lenses
Implementation Method 2
or UV light 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.