DRAM Node Contact Isolation Structure for Short-Fail Prevention
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Solution Overview
Problem
In the formation of node contacts in dynamic random access memory (DRAM), dummy node contacts with unstable silicon oxide in holes lead to device failure due to etching solution penetration, causing short failures in bit lines and node contacts.
Innovation Solution
A method involving a semiconductor base with a substrate and a first oxide material layer, where patterning and etching create oxide line structures and an annular empty slot structure, followed by refilling with a second material to form isolation line structures and a dummy isolation layer, and finally forming conductive material in through hole structures to stabilize the semiconductor structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dummy node contacts are formed at the edge to ensure uniformity of effective node contacts, then the uniformity of node contacts is improved, but the silicon oxide in holes of dummy node contacts becomes unstable and causes device failure
Solution Approach 1:
The dummy node contact region is segmented into two parts: the original hole structure and an additional annular empty slot structure. This segmentation allows the oxide film to be stabilized in the annular region while maintaining the uniformity benefit of dummy contacts, resolving the contradiction between uniformity and stability.
Solution Approach 2:
The annular empty slot structure is formed preliminarily before the etching process. This preliminary structure prevents etching solution from penetrating outward and hollowing out the oxide film, thus preventing the instability issue before it occurs.
2Ease of manufacture
If photoresist is used to cover dummy node contact regions, then coverage is provided, but etching solution penetrates outward when photoresist is poor in coverage or adhesion, causing Short Fail
Solution Approach 1:
The annular empty slot structure acts as an intermediary barrier between the etching solution and the oxide film in dummy node contacts. This intermediary structure prevents direct contact between etching solution and the oxide film, eliminating the need for perfect photoresist coverage and adhesion.
3Productivity
If oxide film is hollowed out by etching solution penetration, then etching process occurs, but the hollowed out oxide film affects array forming process and causes Short Fail of bit lines or node contacts
Solution Approach 1:
The annular empty slot structure provides preliminary anti-action by preventing the harmful effect of etching solution penetration before it can occur. The structure acts as a physical barrier that stops the etching solution from reaching and hollowing out the oxide film in dummy node contacts.
Data Source
AI summary
The present disclosure provides a method for forming semiconductor structure and a semiconductor structure. The method for forming semiconductor structure includes: providing a semiconductor base with a substrate and a first oxide material layer; wherein the first oxide material layer is arranged on the substrate, the first oxide material layer includes a first region and a second region located at edge of the first region; patterning and etching the first oxide material layer; wherein oxide line structures are formed, and an annular empty slot structure is formed; refilling a second material; wherein the second material in the first region forms a plurality of isolation line structures, and the second material in the second region forms an annular dummy isolation layer; removing the oxide line structure by patterning and etching, and forming through hole structures; and forming a conductive material layer in the through hole structures.