Die-Shielded Electroplating Paddle for Via Co-Planarity
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Solution Overview
Problem
Conventional electroplating processes face challenges in achieving uniform thickness of plated films across substrates due to irregularities in electric fields caused by pattern variations and mass-transfer rates, leading to co-planarity issues between densely and sparsely populated regions of vias or pillars.
Innovation Solution
The use of die shields and paddles with specific designs that selectively shield sparse regions from the electric field while allowing current to pass through dense regions, maintaining plating heights in dense areas and reducing them in sparse areas, thereby improving co-planarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electroplating is performed without selective shielding, then the plating process is simple and fast, but the plating thickness is non-uniform across dense and sparse regions
Solution Approach 1:
The electroplating system is segmented into multiple functional components: a paddle with ribs and apertures, and a die shield with shield areas and open areas. These segmented structures allow selective control of electric field distribution across different regions of the substrate, enabling uniform plating thickness while maintaining manageable system complexity through modular design.
Solution Approach 2:
The paddle and die shield incorporate locally differentiated structures where ribs, apertures, shield areas, and open areas are positioned to provide tailored electric field control for specific regions. Dense regions receive shielding to reduce plating, while sparse regions receive enhanced current through apertures and open areas, achieving local quality adjustment for uniform overall plating.
2Manufacturing precision
If the electric field is uniformly distributed across the substrate, then plating thickness is uniform, but this requires complex field control mechanisms
Solution Approach 1:
The paddle and die shield act as intermediary structures between the power source and the substrate. These intermediaries physically modify the electric field distribution through their geometric features (ribs, apertures, shield areas, open areas), simplifying the control mechanism while achieving uniform plating thickness across dense and sparse regions.
Solution Approach 2:
The system changes the spatial distribution parameters of the electric field by introducing structures with varying geometries. The paddle ribs and die shield areas create localized field modifications, while apertures and open areas allow enhanced field penetration in sparse regions, achieving uniform plating through parameter adjustment rather than complex control mechanisms.
3Manufacturing precision
If mass transfer rate is increased to improve plating uniformity, then plating speed increases, but turbulence and process control difficulty increase
Solution Approach 1:
The invention extracts the mass transfer control function from the bulk electrolyte flow and relocates it to localized structures (paddle ribs and die shield features). This extraction allows mass transfer enhancement to be achieved through geometric design rather than increasing overall flow turbulence, simplifying process control while maintaining plating uniformity.
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 approach enhances co-planarity by maintaining consistent plating rates in dense regions while reducing them in sparse regions, improving the overall uniformity of the plated film thickness across the substrate.
Implementation Method 1
The paddle may have an open area of less than about 30%. Each of the plurality of apertures may have a diameter of less than about 10 mm. A position of each of the plurality of apertures may correspond with a dense region of a die pattern used with the electroplating system.
Implementation Method 2
The vessel may include a die shield positioned between the substrate and one or more anodes. The die shield may define a plurality of open areas in between at least one shield area. The plurality of open areas may correspond with dense regions of the substrate. The at least one shield area may correspond with sparse regions of the substrate.
Implementation Method 3
The wafer is then moved into the vessel of an electroplating processor where electric current is conducted through an electrolyte to the wafer, to apply a blanket layer or patterned layer of a metal or other conductive material onto the seed layer.
Implementation Method 4
conducting ionic current through the liquid
Data Source
AI summary
Exemplary electroplating systems may include a vessel. The systems may include a paddle disposed within the vessel. The paddle may be characterized by a first surface and a second surface. The first surface of the paddle maybe include a plurality of ribs that extend upward from the first surface. The plurality of ribs may be arranged in a generally parallel manner about the first surface. The paddle may define a plurality of apertures through a thickness of the paddle. Each of the plurality of apertures may have a diameter of less than about 5 mm. The paddle may have an open area of less than about 15%.