Plating Apparatus Ionically Resistive Element Film Thickness Uniformity
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Solution Overview
Problem
Conventional plating apparatuses experience non-uniform film thickness on the outer peripheral edge of substrates due to the busbar's connecting parts having smaller resistance values as they approach the power feeding part, leading to uneven electricity distribution during the plating process.
Innovation Solution
The plating apparatus incorporates at least one ionically resistive element arranged between the auxiliary anode and the substrate, which increases in resistivity as it approaches the power feeding part, thereby counteracting the uneven electricity distribution caused by the busbar's connecting parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a busbar with connecting parts is used to supply electricity to the auxiliary anode, then electricity can be efficiently supplied to the auxiliary anode, but the film thickness on the outer peripheral edge of the substrate becomes non-uniform due to varying resistance values in the connecting parts
Solution Approach 1:
The patent introduces ionically resistive elements with spatially varying resistivity values. Elements closer to the power feeding part have higher resistivity values, while those farther away have lower resistivity values. This local variation in resistivity compensates for the decreasing resistance of busbar connecting parts, thereby maintaining uniform current distribution and achieving uniform film thickness across the substrate peripheral edge.
2Reliability
If connecting parts with lower resistance values are used closer to the power feeding part, then electrical connection efficiency is improved, but electricity distribution becomes uneven leading to non-uniform film thickness
Solution Approach 1:
The patent applies preliminary anti-action by pre-compensating for the expected uneven current distribution through strategic placement of ionically resistive elements. Before the plating process occurs, resistive elements with appropriate resistivity values are positioned at specific locations to counteract the inevitable current concentration near the power feeding part, thereby preventing non-uniform film thickness formation.
3Manufacturing precision
If ionically resistive elements with higher resistivity are placed closer to the power feeding part, then electricity distribution uniformity is improved, but overall electrical conductivity of the system decreases
Solution Approach 1:
The patent employs local quality by assigning different resistivity values to ionically resistive elements based on their specific positions in the plating tank. Elements near the power feeding part have higher resistivity to reduce current concentration, while elements farther away have lower or zero resistivity to maintain overall conductivity. This spatially differentiated approach achieves uniform current distribution without significantly compromising total system conductivity.
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 effectively suppresses the non-uniformity of film thickness on the outer peripheral edge of the substrate, ensuring a more uniform film thickness across the substrate.
Implementation Method 1
The ionically resistive element is configured to increase in resistivity of the ionically resistive element as approaching the power feeding part in an extending direction of the ionically resistive element
Implementation Method 2
oxygen generated from surfaces of the auxiliary anode
Implementation Method 3
a membrane configured to allow metal ions contained in the plating solution to pass through the membrane and restrict oxygen generated from surfaces of the auxiliary anode from passing through the membrane
Data Source
AI summary
Provided is a technique that allows suppressing a film thickness on an outer peripheral edge of a substrate becoming non-uniform.A plating apparatus 1 includes a plating tank, an anode, a substrate holder, at least one auxiliary anode 60a to 60d, a busbar 61 having a power feeding part 62, to which electricity is supplied, and a plurality of connecting parts 63 connected to the at least one auxiliary anode and arrayed in an extending direction of the auxiliary anode, and at least one ionically resistive element 80a to 80d. The ionically resistive element is configured to increase in resistivity of the ionically resistive element as approaching the power feeding part in an extending direction of the ionically resistive element.