3D Through-Via Liner Structure for Word Line Insulation
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Solution Overview
Problem
The increasing complexity and stack height of three-dimensional semiconductor devices make it challenging to form through-via structures for power supply to string select lines, particularly in ensuring electrical insulation from word lines.
Innovation Solution
The three-dimensional semiconductor device incorporates a substrate with distinct areas, featuring a word line stack with mold layers and word lines alternately stacked, vertical channel structures, and through-via structures with via plugs and liner layers that include dents aligned with word line levels to enhance electrical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If through-via structures are formed to supply power to string select lines in high-stack three-dimensional semiconductor devices, then power supply capability is improved, but electrical insulation from word lines becomes increasingly difficult to maintain
Solution Approach 1:
The via liner layer is configured with different local structures: protruding portions that extend toward word lines to provide electrical insulation, and dents that recess to accommodate mold layers. This local variation in the via liner layer enables simultaneous power supply through the via plug and insulation from word lines through the protruding portions, resolving the contradiction between power supply capability and electrical insulation reliability.
2Device complexity
If finer patterns and through-via structures are formed to increase integration density, then device complexity increases, but manufacturing precision requirements become more stringent
Solution Approach 1:
The via liner layer is formed preliminarily before the word line stack is fully constructed, with protruding portions extending toward where word lines will be positioned. This preliminary action establishes the insulation structure in advance, allowing subsequent word line formation to proceed without requiring additional high-precision alignment steps, thereby reducing manufacturing precision requirements while maintaining high integration density.
Solution Approach 2:
The via liner layer acts as an intermediary structure between the via plug and the word lines. The protruding portions of the via liner layer provide a buffer zone that automatically prevents direct contact between conductive via plugs and word lines, eliminating the need for extremely precise positioning and reducing manufacturing precision requirements.
Data Source
AI summary
A three-dimensional semiconductor device may include a substrate having a cell area and an extension area, a word line stack disposed above the substrate, the word line stack including mold layers and word lines alternately stacked, vertical channel structures vertically penetrating the word line stack in the cell area, and a first extension through-via structure vertically penetrating the word line stack in the extension area. The first extension through-via structure may include a first via plug and a first via liner layer surrounding sidewalls of the first via plug. The first via liner layer may include first dents respectively disposed at the same levels horizontally as the word lines of the word line stack.