IC Opening Formation via Radiation-Imageable Material Ledges
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Solution Overview
Problem
Current methods for forming openings in materials above redistribution layers in integrated circuits face challenges in achieving precise and efficient access to upper conductive nodes, leading to potential defects and increased resistance due to the shape of the openings.
Innovation Solution
The method involves using a radiation-imageable material with a masking tool that allows varying radiation exposure to create openings with annular ledges, enabling the formation of conductive lines that are directly electrically coupled to upper conductive nodes, and subsequent etching to create target-material openings with specific ledge profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical vapor deposition is used to form conductive lines, then the conductive lines can be formed, but 'bread-loafing' shapes occur leading to increased resistance and potential defects
Solution Approach 1:
The method performs preliminary etching to create ledges in the opening before depositing the conductive line. These ledges are formed in advance to prevent the bread-loafing shape that would otherwise occur during physical vapor deposition, thereby ensuring proper conformal coverage and reducing resistance without defects
Solution Approach 2:
The etched ledges act as an intermediary structure between the opening walls and the conductive line. By introducing these intermediate features, the method enables better control over the deposition process and prevents the harmful bread-loafing effect while maintaining electrical connectivity
2Reliability
If openings are formed to access upper conductive nodes, then electrical coupling is achieved, but precise exposure control is difficult leading to potential defects
Solution Approach 1:
The method performs preliminary etching to create ledges that define precise exposure boundaries before conductive line deposition. This preliminary structuring ensures complete and controlled exposure of upper conductive nodes while preventing over-etching or incomplete exposure that could lead to defects
3Manufacturing precision
If conventional etching methods are used, then openings can be formed, but annular ledges with specific profiles cannot be created
Solution Approach 1:
The etching process is segmented into multiple steps with different etch selectivities to create the annular ledge profile. By dividing the etching into stages and using selective etching on different surfaces, the method achieves precise ledge profile control while managing process complexity through systematic segmentation
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 facilitates the formation of integrated circuit structures with smaller upper conductive nodes and reduces the risk of defects by ensuring complete exposure of the nodes, while maintaining low resistance and preventing issues like 'bread-loafing' shapes that can occur with physical vapor deposition.
Implementation Method 1
forming an opening in a material... using a radiation-imageable material with a masking tool that allows varying radiation exposure to create openings with annular ledges
Data Source
AI summary
In some embodiments, a method of forming an opening in a material comprises forming RIM over target material. Radiation is impinged onto the RIM through a masking tool over a continuous area of the RIM under which a target-material opening will be formed. The masking tool during the impinging allows more radiation there-through onto a mid-portion of the continuous area of the RIM in a vertical cross-section than onto laterally-opposing portions of the continuous area of the RIM that are laterally-outward of the mid-portion of the RIM in the vertical cross-section. After the impinging, the RIM is developed to form a RIM opening that has at least one pair of laterally-opposing ledges laterally-outward of the mid-portion of the RIM in the vertical cross-section elevationally between a top and a bottom of the RIM opening. The developed RIM is used as masking material while etching the target material through the RIM opening to form the target-material opening to have at least one pair of laterally-opposing ledges laterally-outward of a mid-portion in the target-material opening in the vertical cross-section elevationally between a top and a bottom of the target-material opening. Other aspects and constructions independent of manufacture are disclosed.