Plated Metallization Structure for Thick IC Features Without Breadloafing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing metallization structures formed by plating are limited in thickness due to the constraints of masking layers, leading to issues like 'breadloafing' which causes electrical shorts and nonplanarity, and increasing masking layer thickness is not practical or desirable under manufacturing constraints.
Innovation Solution
A method involving the use of two masking layers, where a second masking layer forms an opening wider than the first, allowing a second metal to encapsulate the first metal feature, thereby achieving thicker metallization structures without forming a bread loaf structure, by electroplating the second metal to encapsulate the first metal feature and extend laterally beyond it.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the masking layer thickness is increased to form thicker metallization structures, then the metallization thickness can be increased, but manufacturing complexity and difficulty increase significantly
Solution Approach 1:
The patent divides the single thick metallization formation process into two separate plating processes with two different masking layers. The first masking layer forms a narrow opening for the first metal, and the second masking layer forms a wider opening for the second metal that encapsulates the first metal feature. This segmentation allows each masking layer to be of conventional thickness while achieving a combined metallization thickness that exceeds what a single masking layer could provide.
2Length of stationary object
If a single thick metallization structure is formed by plating, then the metallization thickness can be increased, but breadloafing occurs causing electrical shorts and nonplanarity
Solution Approach 1:
The patent segments the metallization structure into two distinct metal features formed at different stages. The first metal feature is formed through a narrow opening, and the second metal feature is formed through a wider opening that encapsulates the first metal feature. This segmentation prevents the breadloafing effect that occurs in single thick plating processes, as each individual plating process uses a masking layer of conventional thickness, ensuring proper planarity and electrical isolation.
Solution Approach 2:
The patent implements a nested structure where the second metal feature encapsulates the first metal feature. The second opening is wider than the first opening, and the second metal feature is formed to surround the first metal feature laterally. This nested configuration ensures that the metallization structure maintains proper geometry and prevents electrical shorts while achieving the desired combined thickness.
3Ease of manufacture
If conventional single masking layer plating is used, then the process is simple and manufacturable, but the metallization thickness is limited by masking layer constraints
Solution Approach 1:
The patent segments the metallization formation into two conventional plating processes, each using a masking layer of standard thickness. While this increases the number of process steps, each individual step remains within conventional manufacturing capabilities. The first process forms a narrow metal feature, and the second process forms a wider metal feature that encapsulates the first, achieving a combined thickness that exceeds single-mask limitations while maintaining manufacturability.
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 approach enables the formation of metallization structures with combined thickness exceeding that of conventional masking layers, reducing the risk of electrical shorts and maintaining manufacturability, while avoiding the defects associated with breadloafing.
Implementation Method 1
plating a first metal on a substrate
Data Source
AI summary
The disclosed technology generally relates to forming metallization structures for integrated circuit devices by plating, and more particularly to plating metallization structures that are thicker than masking layers used to define the metallization structures. In one aspect, a method of metallizing an integrated circuit device includes plating a first metal on a substrate in a first opening formed through a first masking layer, where the first opening defines a first region of the substrate, and plating a second metal on the substrate in a second opening formed through a second masking layer, where the second opening defines a second region of the substrate. The second opening is wider than the first opening and the second region encompasses the first region of the substrate.