Buried Word Line Layout With Dummy Extensions for Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As device manufacturing technology shrinks, active regions in substrates experience increased aspect ratios, leading to bending issues that affect alignment and electrical connections with word lines, and conventional dummy patterns can cause word line disconnection due to etching loading effects.
Innovation Solution
A semiconductor structure with a substrate featuring an array region, periphery region, and dummy region, where word lines extend into the substrate at intersections with a dummy pattern, and include dummy extending portions to maintain alignment and reduce electrical resistance, using a sacrificial material layer to control etching and form continuous word lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a larger dummy pattern is designed at the edge of the array region to prevent active region bending, then the alignment between active regions and word lines is improved, but the substrate in the dummy region protrudes due to etching loading effect, leading to word line disconnection
Solution Approach 1:
The dummy pattern is segmented into multiple sections with varying widths. The dummy pattern includes a first dummy pattern section with a first width and a second dummy pattern section with a second width that is smaller than the first width. This segmentation allows different portions of the dummy pattern to serve different functions: the wider first section provides sufficient support to prevent active region bending, while the narrower second section reduces etching loading to prevent substrate protrusion and word line disconnection.
Solution Approach 2:
Different sections of the dummy pattern are given different local qualities in terms of width. The first dummy pattern section has a larger width to provide mechanical support and prevent bending, while the second dummy pattern section has a smaller width to minimize etching loading effects. This local differentiation allows each section to optimize its function without causing the adverse effects that would result from a uniformly large dummy pattern.
2Productivity
If device manufacturing technology is shrunk to increase density, then the number of active regions per substrate is increased, but the aspect ratio of active regions increases, making them more prone to bending
Solution Approach 1:
The dummy pattern is formed in advance before the word line formation process. By pre-forming the dummy pattern with optimized width variations, the structure is prepared to prevent active region bending before the word lines are created. This preliminary action ensures that when word lines are subsequently formed, the active regions are already stabilized and less prone to bending, enabling reliable miniaturization.
Solution Approach 2:
The dummy pattern acts as an intermediary structure between the active regions and the word lines. It provides mechanical support to the active regions to prevent bending, while its optimized width configuration ensures it does not cause substrate protrusion that would interfere with word line formation. This intermediary structure enables the miniaturization of devices while maintaining the stability of active regions.
Data Source
AI summary
A semiconductor structure includes a substrate and a plurality of word lines. The substrate includes an array region, a periphery region surrounding the array region, and a dummy region between the array region and the periphery region. The array region has a plurality of active regions that are separated from each other by an isolation structure. The dummy region has a dummy pattern. The word lines are buried in the substrate. Each word line extends in the first direction, and the word lines are arranged in the second direction. Each word line has a dummy extending portion that extends into the substrate at the intersection with the dummy pattern. Those dummy extending portions of the word lines are arranged in the second direction.