DRAM Node Contact Structure Using Nitride Dummy Isolation Lines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the manufacturing process of dynamic random access memory (DRAM) node contacts, silicon oxide in dummy node contacts is unstable, leading to erosion by hydrofluoric acid and subsequent conductive metal tungsten filling, causing stray capacitances and bit line-bit line short circuits due to poor photoresist coverage or adhesiveness.
Innovation Solution
A method involving a semiconductor base with a substrate and a first oxide material layer, where pattern etching removes the oxide material layer from a second region to form oxide line structures, allowing a second non-oxide material to fill the region, creating isolation line structures and through holes, which are then filled with a conductive material, reducing instability and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dummy node contacts are formed at the edge part to ensure uniformity in manufacturing process, then manufacturing uniformity is improved, but device reliability deteriorates due to erosion of silicon oxide by hydrofluoric acid causing stray capacitances and bit line short circuits
Solution Approach 1:
The patent applies local quality by differentiating the treatment between the first region (valid node contacts) and the second region (dummy node contacts). A mask pattern selectively covers the first region during etching, leaving the second region exposed for removal. This localized differentiation allows dummy node contacts to be formed for manufacturing uniformity while preventing the reliability issues caused by oxide erosion in dummy contacts.
Solution Approach 2:
The patent segments the oxide material layer into two distinct functional zones: the first region containing valid node contacts that require oxide protection, and the second region containing dummy node contacts where oxide is removed. This segmentation is achieved through selective mask patterning and etching processes, allowing different treatments for different functional requirements.
2Reliability
If photoresist is used to cover dummy node contacts to prevent erosion, then erosion prevention is improved, but process complexity increases due to poor coverage or adhesiveness requiring additional process steps
Solution Approach 1:
Instead of using photoresist to protect the first region (valid node contacts), the patent inverts the approach by selectively removing the oxide from the second region (dummy node contacts) through mask-patterned etching. This eliminates the need for photoresist coverage on dummy contacts and avoids the associated adhesion and coverage problems.
Solution Approach 2:
The patent extracts the problematic oxide material from the second region (dummy node contacts) through selective etching. By removing the oxide that causes erosion issues in dummy contacts, the patent eliminates the need for protective photoresist layers and simplifies the overall process while maintaining reliability.
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
The method significantly reduces instability and enhances the stability and reliability of node contacts by replacing oxide in the second region with a nitride, preventing erosion and improving the semiconductor structure's performance.
Implementation Method 1
performing pattern etching on the first oxide material layer, removing the first oxide material layer of the second region and part of the first oxide material layer of the first region
Implementation Method 2
forming a conductive material layer in the through hole structures to form the semiconductor structure
Data Source
AI summary
A method for forming a semiconductor structure and a semiconductor structure. The method includes: a semiconductor base which has a substrate and a first oxide material layer arranged on the substrate is provided. Pattern etching is performed on the first oxide material layer, to remove the first oxide material layer in the second region and that in a part of the first region, and the remaining first oxide material layer forms oxide line structures on both sides of each bit line structure; a second material is backfilled, to form an isolation line structure in the first region and a dummy isolation structure in the second region; remove the oxide line structures are removed, the bit line structures and the isolation line structures on both sides jointly form through hole structures exposing the substrate; and a conductive material layer is formed in the through hole structures to form the semiconductor structure.