Multi-Layer Metallization with Varying Metal Line Thicknesses
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Solution Overview
Problem
Semiconductor devices require both thick and thin metal lines with varying pitches, which existing metallization technologies struggle to achieve effectively, especially in forming a final metal layer with multiple thicknesses and pitches for diverse applications like logic and power circuits.
Innovation Solution
A method involving multiple electroplating steps to form a final metal layer with metal lines of varying thicknesses, where a first metal layer is deposited followed by a second metal layer with greater thickness, and both are electrically isolated and passivated, allowing for a metallization layer with multiple thicknesses and pitches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single metal layer is used for final metallization, then the manufacturing process is simple, but it cannot satisfy both thick metal lines for power circuits and thin metal lines for logic circuits
Solution Approach 1:
The patent divides the final metal layer into multiple segments with different thicknesses by performing selective electroplating. A first electroplating step forms a base metal layer with first thickness across the entire surface, then a second electroplating step adds a second metal layer with second thickness greater than the first thickness to specific regions. This segmentation allows different portions of the same metal layer to have different thicknesses, enabling both thick power lines and thin logic lines in the final metallization layer.
Solution Approach 2:
The patent applies local quality by making different regions of the final metal layer have different thickness properties. The thicker portions are formed by selective deposition of the second metal layer in specific regions where power circuits require higher current carrying capacity, while other regions maintain the thinner first metal layer thickness suitable for logic circuits. This local differentiation of thickness property allows the metallization to be optimized for different functional requirements within the same layer.
2Manufacturing precision
If multiple electroplating steps are performed to form metal lines of different thicknesses, then both thick and thin metal lines can be achieved in the same layer, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by first forming a base metal layer with uniform thickness across the entire surface before performing selective additional deposition. The first electroplating step establishes a foundation layer that covers all areas, and then the second electroplating step selectively adds material only to regions requiring thicker metal lines. This preliminary uniform deposition simplifies the subsequent selective process and ensures that all regions have at least the minimum required thickness.
Solution Approach 2:
The patent utilizes the vertical dimension (thickness) to differentiate metal line properties within the same planar layer. By performing electroplating in two sequential steps with different deposition thicknesses, the patent creates a multi-level thickness structure where the final metal layer contains both thinner and thicker portions. This dimensional approach allows thickness variation without requiring additional lateral layers, maintaining a relatively simple overall structure while achieving the desired thickness differentiation.
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
Enables the formation of semiconductor devices with a final metal layer comprising metal lines of different thicknesses and pitches, suitable for both logic and power applications, enhancing the semiconductor device's performance and versatility.
Implementation Method 1
first electroplating a first metal layer over the metal seen layer; and second electroplating a second metal layer over the first metal layer
Data Source
AI summary
One or more embodiments are related to a semiconductor device, comprising: a metallization layer comprising a plurality of portions, each of the portions having a different thickness. The metallization layer may be a final metal layer.