Pillar-Shaped Bit Line Contact Structures for Semiconductor Memory Devices
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Solution Overview
Problem
As semiconductor devices become more integrated, design rules for their elements are reduced, necessitating improvements in bit line contact margin to prevent mutual interference and reduce parasitic capacitance.
Innovation Solution
The semiconductor device incorporates a pillar-shaped bit line contact region with an upper surface higher than the field region, a damascene structure for the bit line, and a storage node contact plug, along with a contact spacer and bit line spacer to enhance contact margins and reduce capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If design rules are reduced to increase integration degree, then device integration increases, but bit line contact margin decreases and mutual interference increases
Solution Approach 1:
The patent transitions from a planar bit line contact structure to a three-dimensional pillar-shaped contact structure. The bit line contact region extends vertically from the substrate surface upward, creating multiple spatial dimensions for contact. This vertical extension increases the contact area and margin without occupying additional lateral space, thereby maintaining high integration while improving contact reliability and reducing mutual interference between adjacent bit lines.
2Ease of manufacture
If conventional planar bit line contact structure is used, then manufacturing is simpler, but parasitic capacitance increases and contact margin is insufficient
Solution Approach 1:
The bit line contact structure is segmented into distinct functional regions: the pillar-shaped contact region extending from the substrate, the interlayer insulating layer, and the bit line formed in the trench. This segmentation allows each component to be optimized independently - the pillar contact provides mechanical and electrical stability, the insulating layer provides electrical isolation to reduce parasitic capacitance, and the bit line provides conductive connection. The combined effect reduces parasitic capacitance while maintaining manufacturability through standard semiconductor fabrication processes.
Data Source
AI summary
A semiconductor device includes a substrate having a field region disposed therein that defines an active region of the substrate, the active region comprising a pillar-shaped bit line contact region having an upper surface disposed at a higher level than an upper surface of the field region. An interlayer insulating layer is disposed on the substrate and covers the field region. A bit line is disposed in a trench in the interlayer insulating layer above the pillar-shaped bit line contact region and electrically connected thereto.