Via Contact Structures for Integrated Circuits
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Solution Overview
Problem
Conventional methods face challenges in accurately and reliably forming contact structures in both dense and isolated regions of integrated circuits as device sizes decrease, limiting circuit density and performance.
Innovation Solution
A method involving a semiconductor substrate with distinct regions, forming a device layer, inter-metal dielectric, stop layer, low k dielectric, and cap layer, where via structures are created using etching processes, with the cap layer preventing punch-through and allowing for concurrent formation in dense and isolated regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to form contact structures, then manufacturing simplicity is maintained, but manufacturing precision deteriorates as device sizes decrease
Solution Approach 1:
The contact structure formation process is segmented into two distinct sequences: a first etching sequence for dense regions and a second etching sequence for isolated regions. This segmentation allows each sequence to be optimized independently for its specific region type, thereby improving manufacturing precision for both dense and isolated contact structures while managing process complexity through systematic division.
Solution Approach 2:
Different etching sequences are applied to different regions based on their specific requirements. The first etching sequence with its specific parameters is used for dense regions, while the second etching sequence with different parameters is used for isolated regions. This local quality approach ensures that each region receives the appropriate processing conditions, improving overall manufacturing precision.
2Productivity
If device geometry is reduced to increase circuit density, then productivity is improved, but manufacturing precision deteriorates
Solution Approach 1:
By segmenting the contact formation into separate etching sequences for dense and isolated regions, the patent enables reliable contact structure formation at reduced geometries. Each sequence can be independently optimized for its region type, maintaining manufacturing precision even as overall device density increases.
Solution Approach 2:
The patent employs different etching parameters (chemistry, power, pressure, gas flow ratios) for the first and second etching sequences. These parameter changes allow the process to maintain precision at smaller feature sizes by tailoring the etching conditions to the specific geometry and density of each region type.
3Manufacturing precision
If a single etching process is used for both dense and isolated regions, then device complexity is reduced, but manufacturing precision deteriorates
Solution Approach 1:
The etching process is divided into two distinct sequences: the first etching sequence for dense regions and the second etching sequence for isolated regions. This segmentation improves via structure accuracy for both region types while organizing process complexity into manageable, region-specific steps.
Solution Approach 2:
The first etching sequence is performed as a preliminary action before the second etching sequence. This preliminary etching prepares the dense regions with appropriate depth and profile, and the process parameters are specifically optimized for this initial step, improving overall via structure accuracy.
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 method enhances device yields by enabling precise formation of via structures in both dense and isolated regions, maintaining compatibility with conventional processes and equipment, and preventing punch-through, thus improving circuit density and performance.
Implementation Method 1
the cap layer prevents a punch through of a portion of the stop layer provided in the isolated via structure
Implementation Method 2
via structures are created using etching processes
Data Source
AI summary
A method for fabricating an integrated circuit device includes providing a semiconductor substrate having a first region and a second region, e.g., peripheral region. The method forms a stop layer overlying the first and second regions and a low k dielectric layer (e.g., k<2.9) overlying the stop layer in the first and second regions. The method forms a cap layer overlying the low k dielectric layer. In an embodiment, the method initiates formation of a plurality of via structures within a first portion of the low k dielectric layer overlying the first region and simultaneously initiates formation of an isolated via structure for in the second region of the semiconductor substrate, using one or more etching processes. The method includes ceasing formation of the plurality of via structures within the first portion and ceasing formation of the isolated via structure in the second region when one or more portions of stop layer have been exposed.