Air-Gap Bit Line Spacer Segmentation for Isolation
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Solution Overview
Problem
The existing semiconductor device technologies face challenges in preventing defects caused by the process of forming air-gaps on side surfaces of the bit line structure, which affects electrical isolation and the integrity of the bit line structure.
Innovation Solution
A semiconductor device design that includes a bit line structure with an outer bit line spacer, an inner bit line spacer, a block bit line spacer, and air-gaps between these spacers, where the block bit line spacer has a specific horizontal length and side surface profiles, and the air-gaps are symmetrical and aligned to prevent electrical connections between adjacent storage contact plugs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air-gaps are formed on side surfaces of the bit line structure to provide electrical isolation, then electrical isolation is improved, but defects may occur during the air-gap formation process that affect the integrity of the bit line structure
Solution Approach 1:
The bit line spacer is divided into multiple segments: inner bit line spacer, outer bit line spacer, and block bit line spacer. This segmentation allows the air-gap formation process to be more controlled and precise, reducing defects while maintaining electrical isolation. Each spacer segment serves a specific function in defining the air-gap regions and protecting the bit line structure.
Solution Approach 2:
The block bit line spacer acts as an intermediary element between the inner and outer bit line spacers. It provides a structural bridge that maintains alignment and spacing during the air-gap formation process, preventing defects while ensuring the air-gaps provide adequate electrical isolation.
2Manufacturing precision
If the block bit line spacer has a horizontal length smaller than the outer bit line spacer to enable precise air-gap formation, then manufacturing precision is improved, but the structural complexity increases
Solution Approach 1:
The spacer structure is segmented into three distinct parts with different horizontal lengths and positions. The block bit line spacer has a controlled horizontal length smaller than the outer bit line spacer, which enables precise air-gap formation. This segmentation, while increasing structural complexity, provides the manufacturing precision needed for accurate air-gap definition.
Solution Approach 2:
Different portions of the spacer structure have different properties: the block bit line spacer has a specific horizontal length optimized for air-gap formation, while the outer bit line spacer extends further to provide overall structural support. This local differentiation of properties allows precise air-gap formation without compromising the overall structure.
3Reliability
If air-gaps are formed to prevent electrical connections between adjacent storage contact plugs, then electrical isolation is improved, but the process complexity increases
Solution Approach 1:
The inner, outer, and block bit line spacers are formed in advance before the storage contact plugs are created. This preliminary action defines the air-gap regions beforehand, ensuring that when storage contact plugs are subsequently formed, they are automatically electrically isolated by the pre-established air-gaps, simplifying the overall process flow.
Solution Approach 2:
The spacer system is segmented into multiple functional parts that collectively create the air-gap structure. This segmentation allows the electrical isolation function to be achieved through a structured, multi-component approach rather than a single complex process step.
Data Source
AI summary
A semiconductor device includes a bit line structure located on a semiconductor substrate, an outer bit line spacer located on a first side surface of the bit line structure, an inner bit line spacer including a first part located between the bit line structure and the outer bit line spacer and a second part located between the semiconductor substrate and the outer bit line spacer, and a block bit line spacer located between the outer bit line spacer and the second part of the inner bit line spacer. A first air-gap is defined by the outer bit line spacer, the inner bit line spacer, and the block bit line spacer.