Flexible Seal for Electroplating Leakage and Rotation
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Solution Overview
Problem
Existing electroplating processes for semiconductor wafers suffer from significant electroplating solution leakage through the gap between the cup member and the insert member, leading to reduced metal ion supply and plating throughput, as well as poor within-feature and within-die uniformity due to the inability to rotate the wafer without damaging seals or compromising sealing effectiveness.
Innovation Solution
A flexible annular-disk-shaped seal member is used, conforming to the upward slope of the insert member's top surface, with an inner radial portion projecting inward to form a liquid seal with the cup member, allowing continuous rotation and minimizing leakage by utilizing electroplating solution flow pressure to enhance sealing, made from durable, low-friction materials like PTFE or elastomer mixtures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid seal is used between the cup member and insert member, then sealing effectiveness is improved, but the ability to accommodate misalignment and maintain sealing under dynamic conditions deteriorates
Solution Approach 1:
The patent employs a flexible seal member comprising an elastomeric material that can deform and conform to the interface between the cup member and insert member. This flexibility allows the seal to maintain effective contact and prevent solution leakage while accommodating misalignment and dynamic movements during the electroplating process, thereby resolving the contradiction between sealing effectiveness and adaptability.
2Manufacturing precision
If the wafer is rotated during electroplating to improve uniformity, then within-feature and within-die uniformity are improved, but seal damage and compromised sealing effectiveness occur
Solution Approach 1:
The flexible elastomeric seal member can withstand and accommodate the dynamic conditions created by wafer rotation. Its elasticity allows it to maintain sealing contact while flexing during rotational movement, enabling the process to achieve improved uniformity through rotation without compromising seal integrity or causing damage to the sealing mechanism.
3Loss of substance
If the gap between cup member and insert member is reduced to minimize leakage, then electroplating solution leakage is reduced, but the ability to rotate the wafer without damaging seals deteriorates
Solution Approach 1:
The flexible elastomeric seal enables the system to maintain a small gap for minimal leakage while still accommodating wafer rotation. The seal's ability to deform elastically allows it to function effectively in the constrained space of a small gap while withstanding the mechanical stresses of rotational movement, thus resolving the contradiction between minimizing leakage and maintaining rotation capability.
4Loss of substance
If a complex sealing mechanism is used to prevent leakage, then electroplating solution leakage is reduced, but device complexity increases
Solution Approach 1:
The patent employs a relatively simple flexible elastomeric seal member that achieves effective leakage prevention through its material properties and geometric configuration rather than through complex mechanical mechanisms. This single-component flexible seal design minimizes device complexity while maintaining low leakage performance, resolving the contradiction between leakage reduction and mechanism simplicity.
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 significantly reduces electroplating solution leakage, enabling high throughput and uniform deposition while allowing continuous wafer rotation, maintaining optimal plating conditions and improving within-feature and within-die uniformity, with a large effective range of operation and reduced setup sensitivity.
Implementation Method 1
A portion of the electroplating solution flows against a bottom surface of the inner radial portion of the seal member and presses the seal member against the cup member to assist with maintaining the liquid seal
Implementation Method 2
The seal member is flexible such that an outer radial portion of the seal member conforms to the upward slope of the top surface of the insert member
Implementation Method 3
forming a liquid seal with a top surface of the inner radial portion of the seal member
Data Source
AI summary
An apparatus for electroplating a semiconductor wafer includes an insert member configured to circumscribe a processing region. The insert member has a top surface. A portion of the top surface of the insert member has an upward slope that slopes upward from a peripheral area of the top surface of the insert member toward the processing region. The apparatus also includes a seal member having an annular-disk shape. The seal member is positioned on the top surface of the insert member. The seal member is flexible such that an outer radial portion of the seal member conforms to the upward slope of the top surface of the insert member and such that an inner radial portion of the seal member projects inward toward the processing region.