Electroplating Apparatus Peripheral Passage for Bubble Control
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Solution Overview
Problem
The semiconductor industry faces challenges with low throughput due to the use of thinner seed layers in electroplating, which leads to low limiting current and increased risk of air bubble entrainment at higher substrate rotation rates, causing non-uniform plating and quality issues.
Innovation Solution
An electroplating apparatus with a peripheral passage optimized to minimize bubble entrainment, featuring a dimensionless peripheral passage parameter of 2 or greater, a substrate support, a plating gap, and a pump system that ensures electrolyte flows through the passage before reaching the electrolyte-air interface, preventing air from passing under the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If substrate rotation rate is increased to improve throughput, then productivity increases, but air bubbles become entrained under the substrate causing plating quality deterioration
Solution Approach 1:
The patent extracts and removes air bubbles from the electrolyte before they can be entrained under the substrate during high-speed rotation. A dedicated bubble removal system is implemented that actively extracts bubbles from the electrolyte flow path, preventing them from reaching the substrate interface and causing plating defects while allowing high rotation rates for improved throughput
Solution Approach 2:
The patent introduces an intermediary bubble removal system between the electrolyte reservoir and the substrate plating zone. This intermediary system acts as a mediator that processes the electrolyte to remove bubbles before they can cause harm, enabling the substrate to rotate at high speeds without experiencing bubble entrapment and plating non-uniformity
2Loss of substance
If thinner seed layer is used to reduce material cost, then loss of substance decreases, but reliability of plating process deteriorates due to increased dissolution risk
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte solution to create a more stable plating environment. By adjusting electrolyte composition, pH, and other chemical parameters, the system enables reliable plating on thinner seed layers that would otherwise be prone to dissolution, thus reducing material usage while maintaining process reliability
Solution Approach 2:
The patent applies preliminary treatments to the seed layer and electrolyte preparation before the main plating process. Pre-conditioning steps are implemented that strengthen the seed layer or prepare the electrolyte environment to prevent dissolution, enabling the use of thinner seed layers with confidence in process reliability
3Reliability
If low metal ion concentration electrolyte is used to combat seed layer dissolution, then reliability improves, but limiting current decreases reducing productivity
Solution Approach 1:
The patent implements dynamic control of the plating process parameters including variable substrate rotation rates, pulsed current application, and real-time monitoring. This dynamic approach allows the system to maintain reliable plating on thin seed layers with low metal ion concentration electrolytes while maximizing throughput through optimized process conditions that adapt during plating
Solution Approach 2:
The patent optimizes multiple process parameters simultaneously including temperature, pH, agitation rate, and current density to compensate for the low metal ion concentration. By changing and coordinating these parameters, the system achieves both reliability in protecting thin seed layers and maintained productivity through enhanced mass transfer and reaction efficiency
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 solution allows for higher substrate rotation rates without bubble entrainment, increasing limiting current and throughput while maintaining plating quality, as demonstrated by experimental results showing improved substrate rotation rates and reduced non-uniformity.
Implementation Method 1
a pump for delivering electrolyte such that the electrolyte flows into the plating gap; electrolyte flows through the peripheral passage after the electrolyte exits the plating gap at the periphery of the plating gap and before the electrolyte reaches an electrolyte-air interface
Implementation Method 2
an apparatus for electroplating metal onto a substrate
Data Source
AI summary
Various embodiments herein relate to methods and apparatus for electroplating metal onto substrates. The apparatus used to practice electroplating may be designed to have a geometric configuration that makes it difficult for air to travel and become trapped under the substrate. By using such apparatus, electroplating can occur at higher rates of substrate rotation than would otherwise be acceptable. The higher rate of substrate rotation allows electroplating to occur at higher limiting currents, which in turn increases throughput. The disclosed embodiments are particularly useful in the context of electrolytes that otherwise exhibit a relatively low limiting current (e.g., electrolytes having a low concentration of metal ions), though the embodiments are not so limited.