Interchangeable Contact Ring for Electroplating Throughput
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Solution Overview
Problem
Conventional electroplating systems face inefficiencies due to the need for periodic maintenance of contact rings and seals, which leads to reduced throughput and uniformity of metal layers on wafers, as metal ions plate onto electrical contacts and contaminate the wafer, requiring time-consuming deplating and cleaning processes.
Innovation Solution
The contact ring is designed to be removable and interchangeable, allowing for quick replacement and deplating within the system, reducing idle time and enabling continuous processing by using a chuck assembly that attaches to a rotor, facilitating efficient deplating and cleaning of contact rings and seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the contact ring is fixed and continuously used during electroplating, then the plating process can run continuously, but metal ions plate onto the contacts causing contamination and non-uniform plating, requiring periodic deplating maintenance that reduces throughput
Solution Approach 1:
The contact ring is divided into multiple independent contact elements arranged in a circular pattern. Each contact element can be independently replaced or cleaned without affecting the others, allowing maintenance of one segment while others remain operational, thus maintaining throughput while ensuring plating uniformity
Solution Approach 2:
The contact ring is designed to be rotatable relative to the wafer, allowing dynamic adjustment of contact positions during plating. This rotation distributes wear and plating deposition more evenly across all contact elements, preventing localized buildup that would cause non-uniform plating, while maintaining continuous operation
2Reliability
If reverse current is applied to deplate the contacts, then metal can be removed from the contacts, but the deplating process takes significant time due to current limitations and agitation constraints
Solution Approach 1:
A cleaning mechanism is implemented that periodically removes plated metal from contact elements before it accumulates to problematic levels. This preliminary cleaning action prevents the need for extensive deplating operations, reducing maintenance time while ensuring contact cleanliness is maintained throughout operation
Solution Approach 2:
The system enables continuous plating operation by implementing rapid contact ring replacement or in-situ cleaning capabilities. The contact ring can be quickly removed and replaced with a fresh one, or cleaned in-place using ultrasonic or chemical methods, allowing the plating process to resume immediately without lengthy deplating cycles, thus maintaining continuous useful action
3Manufacturing precision
If a seal is used in dry contact electroplating processors to keep plating solution away from contacts, then contact contamination is reduced, but the seal requires periodic cleaning and maintenance that reduces system throughput
Solution Approach 1:
The seal component is completely removed from the system by transitioning to a wet-contact design where contacts are intentionally exposed to plating solution. This extraction of the seal eliminates its maintenance requirements and potential failure points, while the periodic rapid replacement or cleaning of contact rings themselves maintains plating uniformity without reducing overall system throughput
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 significantly reduces processor idle time, enhances the uniformity of metal layers on wafers, and improves the overall efficiency of the electroplating process by allowing continuous operation without the need for extensive maintenance during plating cycles.
Implementation Method 1
The metal layers are generally applied to the wafers via electrochemical plating in an electroplating processor. A typical electroplating processor includes a vessel or bowl for holding an electroplating solution, one or more anodes in the bowl in contact the electroplating solution, and a head having a contact ring with multiple electrical contacts that touch the wafer. The front surface of the wafer is immersed in the electroplating solution and an electrical field causes metal ions in the electroplating solution to plate out onto the wafer, forming a metal layer.
Implementation Method 2
Typically, the contacts are deplated by immersing the contact assembly into the plating solution while passing reverse electrical current through them. The reverse current causes the plating cycle to reverse, moving metal off of the contacts and back into the solution.
Data Source
AI summary
In a processing system for electroplating semiconductor wafers and similar substrates, the contact ring of the electroplating processor is removed from the rotor of the processor and replaced with a previously deplated contact ring. This allows the contact ring to be deplated in ring service module of the system, while the processor continues to operate. Wafer throughput is improved. The contact ring may be attached to a chuck for moving the contact ring between the processors and the ring service module, with the chuck quickly attachable and releasable to the rotor.