Wafer Electroplating Membrane Support for Uniform Metal Deposition
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Solution Overview
Problem
Existing electroplating technologies for semiconductor wafers face challenges in achieving uniform thickness of the metal film due to non-uniform electromagnetic fields and ion distribution across the wafer surface.
Innovation Solution
A plating apparatus is designed with a membrane support configured as an ion shield, featuring ion blocking regions and ion flow-through regions. This apparatus directs a greater flow of ions to the center of the wafer, compensating for the stronger electromagnetic field at the edges, thereby promoting uniform metal film deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electroplating is used without ion shielding, then the plating process is simple, but the metal film thickness is non-uniform across the wafer surface
Solution Approach 1:
An ion shield is introduced as an intermediary component between the ion source and the wafer. This ion shield selectively blocks ions from reaching certain regions (particularly edge portions) of the wafer, thereby mediating the ion distribution to achieve more uniform metal film thickness across the wafer surface.
Solution Approach 2:
The ion shield is designed with non-uniform properties - it has different blocking characteristics for different regions of the wafer. Specifically, it provides greater blocking at the edges and less blocking at the center, creating local variations in ion flow that compensate for the natural non-uniformity of electromagnetic field distribution.
2Manufacturing precision
If ion flow is not controlled, then the plating process is fast, but the electromagnetic field causes stronger deposition at edges leading to non-uniform thickness
Solution Approach 1:
The ion shield creates local variations in ion flow by blocking ions preferentially at the wafer edges while allowing more ions to reach the center region. This local modulation of ion distribution compensates for the edge-enhanced deposition caused by the electromagnetic field, achieving uniform thickness without significantly reducing overall plating rate.
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 ensures a uniform thickness of the metal film across the wafer surface by effectively managing ion flow and electromagnetic field distribution, enhancing the consistency and quality of semiconductor wafer electroplating.
Implementation Method 1
directs a flow of ions of a metal to the wafer where the ions interact with the wafer to form the metal film
Implementation Method 2
non-uniform electromagnetic fields and ion distribution across the wafer surface
Implementation Method 3
electroplating semiconductor wafers
Data Source
AI summary
A plating apparatus for electroplating a wafer includes a housing defining a plating chamber for housing a plating solution. A voltage source of the apparatus has a first terminal having a first polarity and a second terminal having a second polarity different than the first polarity. The first terminal is electrically coupled to the wafer. An anode is within the plating chamber, and the second terminal is electrically coupled to the anode. A membrane support is within the plating chamber and over the anode. The membrane support defines apertures, wherein in a first zone of the membrane support a first aperture-area to surface-area ratio is a first ratio, and in a second zone of the membrane support a second aperture-area to surface-area ratio is a second ratio, different than the first ratio.