Thief Tunnel Apparatus for Uniform Plating Film Thickness
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Solution Overview
Problem
Conventional plating processes for substrates like semiconductor wafers face issues with uneven film thickness due to concentrated electric current and varying resist patterns, requiring complex shield plate designs and adjustments, especially for angular substrates, which complicate the plating process and result in inconsistent film deposition.
Innovation Solution
The introduction of a thief tunnel apparatus with a body having an opening and auxiliary electrodes along its circumference, protected by an ion exchange membrane, allows independent control of voltages applied to these electrodes to regulate the electric current and field distribution, thereby controlling the plating film thickness uniformly across the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a shield plate is placed to equalize electric current flow, then plating uniformity is improved, but device complexity increases due to complicated design and adjustment requirements for different substrates
Solution Approach 1:
The shield plate is divided into multiple independently controllable segments or regions, each capable of having its electric potential adjusted separately. This allows localized control of electric field distribution to address specific non-uniformity issues in different areas of the substrate without requiring complete redesign of the entire shield plate structure.
Solution Approach 2:
The electric potential of the shield plate or its segments is made variable and adjustable, allowing the system to adapt to different substrate types, resist patterns, and plating conditions. By changing the potential parameters dynamically, the same shield plate structure can serve multiple product configurations without mechanical redesign.
2Adaptability or versatility
If the opening size of the shield plate is changed to adapt to different products, then adaptability is improved, but device complexity increases due to automatic control mechanisms required
Solution Approach 1:
The shield plate structure is designed to perform multiple functions: it serves as both a physical barrier and an electric field control element. By integrating potential control capabilities, the same structure adapts to different product requirements without requiring separate specialized components for each application scenario.
Solution Approach 2:
Instead of mechanically changing the opening size, the system achieves adaptability by changing the electric potential parameters of the shield plate. This allows the same physical structure to accommodate different substrates and plating requirements through electronic control rather than mechanical reconfiguration.
3Device complexity
If conventional electric field control methods are used, then plating process is simple, but plating quality is insufficient due to uneven film thickness
Solution Approach 1:
Different regions of the shield plate are assigned different electric potentials to create localized electric field distributions. This allows specific areas of the substrate to receive tailored electric field strength, compensating for local variations in resist pattern density, seed layer thickness, or substrate geometry to achieve uniform plating across the entire 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
This configuration enhances the uniformity of plating film thickness by independently controlling electric current distribution, reducing the need for complex mechanical adjustments and maintaining the quality of plating across different substrates with varying resist patterns and shapes.
Implementation Method 1
an ion exchange membrane configured to protect the auxiliary electrodes from a plating solution
Implementation Method 2
a plurality of auxiliary electrodes arranged along a circumference of the opening. At least one of the auxiliary electrodes is configured such that a voltage to be applied to the at least one of the auxiliary electrodes is controlled independently
Implementation Method 3
an anode configured to make electric current flow between the substrate and the anode
Data Source
AI summary
There is provided an apparatus for plating a substrate as an object to be plated. The apparatus comprises an anode and a thief tunnel arranged to be located between the substrate and the anode when the substrate is placed to be opposed to the anode. The thief tunnel comprises a body placed away from the substrate and provided with an opening; a plurality of auxiliary electrodes provided in or to the body; and an ion exchange membrane configured to protect the auxiliary electrodes from a plating solution. The plurality of auxiliary electrodes are arranged along a circumference of the opening. At least one of the auxiliary electrodes is configured such that a voltage to be applied to the at least one of the auxiliary electrodes is controlled independently of a voltage to be applied to one or more auxiliary electrodes other than the at least one of the auxiliary electrodes.