Semiconductor Insulating Structure Against Etch-Induced Pinhole Defects
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Solution Overview
Problem
As semiconductor device components are miniaturized, defects such as pinholes in insulating structures between conductive regions can occur due to etching processes, leading to reliability issues, particularly when buffer layers are partially etched, causing the line portions to collapse.
Innovation Solution
A semiconductor device design incorporating a stable insulating structure with a spacer made of silicon carbonitride, an insulating pattern of silicon nitride, and a liner of silicon oxide, which are distinct materials, to enhance the reliability by preventing defects during etching and maintaining structural integrity between conductive regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-material insulating structure is used between conductive regions, then the manufacturing process is simple, but pinholes form during etching and buffer layers are partially etched causing line collapse
Solution Approach 1:
The insulating structure uses a composite material system with three distinct layers: a first insulating layer (silicon oxide) in contact with the conductive region, a second insulating layer (silicon nitride) as an intermediate layer, and a third insulating layer (silicon carbonitride) as the outer layer. Each material is selected for its specific etching resistance properties, creating a multi-material barrier that prevents pinhole formation and buffer layer etching while maintaining manufacturing feasibility through sequential deposition processes.
Solution Approach 2:
The insulating structure is segmented into three distinct functional layers rather than using a single uniform material. The first insulating layer provides baseline insulation, the second insulating layer adds etching resistance, and the third insulating layer provides enhanced protection during oxide etching processes. This segmentation allows each layer to perform its specific function optimally, preventing defects that would occur with a single-material approach.
2Productivity
If component sizes are reduced to enhance performance, then device density increases, but defects occur between adjacent conductive regions
Solution Approach 1:
The multi-material insulating structure provides enhanced defect prevention capability that enables further miniaturization. The composite barrier of three insulating layers with different etching resistances creates a more robust protection system that maintains reliability even as conductive regions are placed closer together, allowing device density to increase without proportionally increasing defect rates.
3Ease of manufacture
If buffer layers are removed during oxide etching, then the etching process is complete, but line portions collapse due to loss of structural support
Solution Approach 1:
The first insulating layer is deposited and cured before the oxide etching process to create a protective barrier that prevents buffer layer removal. This preliminary protective action allows the oxide etching to proceed efficiently while the insulating layer maintains structural support, preventing line collapse. The insulating layer is applied in advance to anticipate and prevent the structural weakness that would occur after buffer layer removal.
Solution Approach 2:
The multi-layer insulating structure acts as a cushioning barrier that compensates for the loss of buffer layer support during etching. The first insulating layer specifically provides this cushioning effect by maintaining structural integrity during the oxide removal process, preventing line portions from collapsing even though the buffer layers are being removed as intended.
4Reliability
If a multi-material insulating structure is used, then pinhole formation is reduced and structural integrity is maintained, but the device complexity increases
Solution Approach 1:
The patent employs a composite material system with three insulating layers, each with specific functional properties. While this increases material complexity, the sequential deposition process using standard semiconductor manufacturing techniques keeps process complexity manageable. The benefits of defect reduction and structural integrity maintenance during miniaturization outweigh the increased complexity of the multi-material structure.
Data Source
AI summary
A semiconductor device includes an active region; an isolation region on a side surface of the active region; a gate trench intersecting the active region and extending into the isolation region; a gate structure in the gate trench; a first impurity region and a second impurity region in the active region on both sides of the gate structure and spaced apart from each other; a bit line structure including a line portion intersecting the gate structure and a plug portion below the line portion and electrically connected to the first impurity region; and an insulating structure on a side surface of the plug portion. The insulating structure includes a spacer including a first material; an insulating pattern between the plug portion and the spacer and including a second material; and an insulating liner covering a side surface and a bottom surface of the insulating pattern and including a third material.