Electrolytic Paddle with Variable Agitation Rod Gaps
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Solution Overview
Problem
The existing substrate electrolytic processing apparatuses face challenges in achieving uniform electric-field shielding rates, leading to non-uniform metal film thickness on substrates due to the paddle's width being smaller than the substrate diameter, resulting in thicker films at the peripheral portions compared to the central portions.
Innovation Solution
A paddle design with agitation rods arranged in an inner and outer region, where the gaps between the outer agitation rods are smaller than those in the inner region, and the gaps gradually decrease with distance from the central axis, ensuring uniform electric-field shielding across the substrate surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the paddle width is increased to achieve uniform electric-field shielding rate across the substrate, then the uniformity of metal film thickness is improved, but the size of the processing apparatus increases
Solution Approach 1:
The paddle is designed with non-uniform gap distribution between agitation rods, where gaps in the outer region are smaller than gaps in the inner region. This local variation in gap size creates different electric-field shielding characteristics in different regions of the paddle, allowing the entire substrate surface to receive uniform electric-field shielding despite the paddle's limited width.
2Device complexity
If the paddle width is kept small to maintain compact apparatus size, then the device complexity is reduced, but the electric-field shielding rate becomes non-uniform across the substrate
Solution Approach 1:
The gap distances between adjacent agitation rods are varied as a design parameter, with gaps in the outer region being smaller than gaps in the inner region. This parameter change allows the paddle to achieve uniform electric-field shielding rate across the substrate surface while maintaining a compact size, resolving the contradiction between apparatus size and shielding 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 design allows for the formation of a metal film with uniform thickness on the substrate without increasing the size of the processing apparatus, by maintaining a consistent electric-field shielding rate across the substrate surface.
Implementation Method 1
The paddle 105 is disposed in a vertical position, and is configured to reciprocate parallel to the surface of the substrate W to thereby agitate the plating solution so that a sufficient amount of metal ions can be supplied uniformly to the surface of the substrate W
Implementation Method 2
When a voltage is applied between the anode 102 and the substrate W, an electric current is passed to the substrate W, so that a metal film is formed on the surface of the substrate W
Implementation Method 3
The regulation plate 106 is disposed between the paddle 105 and the anode 102, and has an opening 106a for restricting an electric field, in the plating solution
Implementation Method 4
Since the paddle 105 is located in the electric field between the anode 102 and the substrate W, the agitation rods 108 reciprocates from side to side as shown by arrows while shielding the substrate from the electric field
Data Source
AI summary
A substrate electrolytic processing apparatus capable of leveling an electric-field shielding rate with no need to increase its size is disclosed. The substrate electrolytic processing apparatus includes a processing bath for holding a processing solution, a substrate holder for holding a substrate and capable of locating the substrate in the processing bath, a counter electrode disposed in the processing bath and serving as an electrode opposite to the substrate, and a paddle disposed between the counter electrode and the substrate and configured to reciprocate parallel to a surface of the substrate so as to agitate the processing solution. The paddle includes agitation rods disposed in an inner region of the paddle and agitation rods disposed in an outer region of the paddle, and gaps between the agitation rods disposed in the outer region is smaller than gaps between the agitation rods disposed in the inner region.