Closed-Contact Electroplating Cup Assembly for Wafer Edge Plating
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Solution Overview
Problem
Current electroplating systems limit the usable wafer surface area for integrated circuit fabrication due to exposed electrical contacts, leading to unplated regions and potential damage during the removal process, which reduces the effective area for device fabrication.
Innovation Solution
A closed-contact electroplating cup assembly with a seal and electrical contact structure that prevents plating solution exposure to electrodes, allowing for uniform copper deposition up to the wafer edge and minimizing defects, featuring a wafer-centering mechanism and specific design elements like a flattened inner perimeter seal to accommodate wafer notches and ensure uniform electric field distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If open contact plating systems are used with exposed electrodes, then electrical current can be delivered to the seed layer, but the electrodes are plated to the substrate surface and create unplated regions that reduce usable wafer area
Solution Approach 1:
The patent extracts the electrical contact function from the plating solution environment by using closed-contact electrodes that deliver current through the wafer背面 (back side), completely isolating the contact mechanism from the plating chemistry. This eliminates the electrode-induced unplated regions on the wafer surface.
Solution Approach 2:
The patent introduces an intermediary mechanism (closed-contact electrode structure with seal) that transfers electrical current to the wafer without direct exposure to the plating solution. The seal acts as a mediator that prevents solution contact while maintaining electrical connectivity through the wafer back side.
2Ease of operation
If open contact plating systems are used, then electrodes can contact the substrate surface for current delivery, but removal of electrodes causes damage to the copper layer and renders outer perimeter unsuitable for fabrication
Solution Approach 1:
The patent extracts the electrode contact point from the plating solution and wafer front surface, relocating it to the wafer back side. This eliminates the mechanical damage and copper layer degradation that occur during electrode removal from the front surface.
Solution Approach 2:
The patent inverts the traditional electrode contact approach by contacting the wafer from the back side rather than the front side. This reversal allows current delivery without interfering with the plating process or damaging the copper layer on the front surface.
3Productivity
If more wafer surface is used for device fabrication, then quantity of devices per wafer increases, but electroplating contacts and structures limit the amount of surface area that can be plated
Solution Approach 1:
The patent extracts the contact structures from the plating solution environment and relocates them to the wafer back side, completely eliminating their footprint on the plated surface. This maximizes the plated area available for device fabrication.
Solution Approach 2:
The patent moves the electrical contact function to another dimension (the back side of the wafer) rather than occupying space on the front plated surface. This dimensional relocation allows 100% of the front surface to be used for plating and device fabrication.
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
Enables the use of a greater wafer surface area for device fabrication with reduced defects and improved film thickness uniformity, maintaining low defect counts and uniformity up to 3 mm from the wafer edge, enhancing the yield and quality of integrated circuits.
Implementation Method 1
a seal disposed on the cup bottom around the opening... preventing plating solution exposure to electrodes
Implementation Method 2
electrical contact structure disposed over a portion of the seal... deliver electric current to the seed layer during plating
Implementation Method 3
electroplating is used to deposit a thicker copper layer over the seed layer such that the channels are completely filled
Implementation Method 4
electroplating is used to deposit a thicker copper layer over the seed layer
Implementation Method 5
a wafer-centering mechanism configured to center a wafer in the cup assembly
Data Source
AI summary
Embodiments of a closed-contact electroplating cup are disclosed. One embodiment comprises a cup bottom comprising an opening, and a seal disposed on the cup bottom around the opening. The seal comprises a wafer-contacting peak located substantially at an inner edge of the seal. The embodiment also comprises an electrical contact structure disposed over a portion of the seal, wherein the electrical contact structure comprises an outer ring and a plurality of contacts extending inwardly from the outer ring, and wherein each contact has a generally flat wafer-contacting surface. The embodiment further comprises a wafer-centering mechanism configured to center a wafer in the cup.