Wafer Coating Ring for Edge Homogeneity
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Solution Overview
Problem
Existing wafer coating systems face challenges in achieving homogeneous coating, particularly in the edge area of larger wafers, such as those with a 300 mm diameter, due to uneven distribution of coating materials.
Innovation Solution
A device with a concentrically arranged L-shaped ring around the wafer expands the coating surface, ensuring a uniform distance between the wafer and the ring, allowing for improved coating homogeneity by preventing sticking and facilitating even material distribution and easy cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If spray coating is applied to large wafers (300 mm diameter), then the wafer surface area to be coated increases, but coating homogeneity in the edge area deteriorates
Solution Approach 1:
The invention introduces a vertical dimension by adding a ring structure that extends upward from the wafer periphery. This ring creates a three-dimensional coating environment where coating material can be deposited from multiple directions (horizontal spray and vertical accumulation on the ring), ensuring better edge coverage and homogeneity across the entire wafer surface including the previously problematic edge areas.
Solution Approach 2:
The coating system is segmented into two functional components: the wafer surface to be coated and the surrounding ring structure. The ring acts as a separate element that collects and redistributes coating material, particularly at the wafer edges. This segmentation allows independent optimization of edge coating through the ring while maintaining central area coverage, resolving the homogeneity issue across different wafer regions.
2Manufacturing precision
If the ring is positioned close to the wafer edge to improve edge coating, then coating homogeneity improves, but wafer sticking to the ring occurs
Solution Approach 1:
The invention introduces a gap or intermediate space between the wafer edge and the ring inner circumference. This intermediate region allows coating material to be deposited uniformly on the wafer edge without direct contact between the wafer and ring. The gap acts as a mediator that enables close proximity positioning for better edge coating while preventing the harmful sticking effect.
3Manufacturing precision
If the ring structure is added to improve coating homogeneity, then coating uniformity improves, but device complexity increases
Solution Approach 1:
The ring structure serves multiple functions simultaneously: it acts as a coating material collector, a redistribution mechanism for edge areas, a structural support element, and a defining boundary for the coating zone. By consolidating these multiple functions into a single component, the invention achieves improved coating uniformity without proportionally increasing device complexity.
4Device complexity
If conventional spray coating is used, then the coating process is simple, but cleaning frequency and effort increase due to excess material
Solution Approach 1:
The ring structure functions as a recovery mechanism by collecting excess coating material that would otherwise be wasted or require frequent cleaning. The ring captures and holds the excess material in a controlled manner, allowing for less frequent cleaning intervals and reduced maintenance effort while maintaining the simplicity of the spray coating process.
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 enhances the homogeneity of the coating in the edge area of the wafer, allowing for more uniform coverage and easier maintenance by ensuring the coating material adheres predominantly to the ring, reducing the need for frequent cleaning of other device components.
Implementation Method 1
a nozzle device (10) for coating the surface (2o) with a coating substance
Data Source
Figure 1~2
AI summary
The invention relates to an apparatus for coating a surface (2o) of a wafer (2), - comprising a receptacle device (16) for receiving the wafer (2) on a receptacle surface (19) and - a nozzle device (10) for coating the wafer (2) in a Z-direction, characterized in that on a lateral circumference (2a) of the wafer (2) it is possible to arrange a ring (4) surrounding the wafer (2) with an inner circumference (4i) and serving for extending a coating area when coating the wafer (2).