Word Line Width Layout for DRAM Leakage Control
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Solution Overview
Problem
As semiconductor structures are scaled down, current leakage becomes a critical concern due to the shrinking dimensions and pitches of signal lines in memory devices like DRAM, affecting electrical characteristics, quality, cost, and yield.
Innovation Solution
A semiconductor structure is designed with central and edge word lines, where the edge word line has a greater width than the central word lines, and a method of manufacturing involving a sacrificial structure, photomask with specific opaque and transparent portions, and material layer formations to create these word lines, ensuring proper dimensions and reduced leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the dimensions and pitches of word lines are scaled down to meet application requirements, then the device density and integration are improved, but current leakage increases
Solution Approach 1:
The patent applies different widths to edge word lines versus central word lines. Edge word lines have a first width while central word lines have a second width, creating local quality variations that address current leakage at specific locations without affecting the entire array. This allows optimization for current leakage control at edge regions while maintaining scaled dimensions in central regions.
Solution Approach 2:
The patent changes the width parameter of word lines based on their location in the semiconductor structure. By varying the width parameter (first width for edge, second width for central), the patent addresses current leakage issues while maintaining overall scaling. This parameter change allows different electrical characteristics in different regions of the same structure.
2Reliability
If the width of edge word lines is increased to reduce current leakage, then the electrical characteristics are improved, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the word line array into edge regions and central regions, with each segment having different width characteristics. This segmentation is achieved through divided sacrificial structures and corresponding photomask regions, allowing independent control of edge and central word line widths while using a unified manufacturing process flow.
Solution Approach 2:
The patent uses sacrificial structures as intermediary elements to define the different widths of edge and central word lines. These sacrificial structures are formed with varying widths corresponding to the desired final word line widths, and they serve as templates during the formation process. The photomask with transparent and opaque portions acts as another intermediary to selectively remove sacrificial material and define the final word line geometry.
3Object-generated harmful factors
If different widths of word lines are implemented, then the current leakage is controlled, but the manufacturing precision requirements increase
Solution Approach 1:
The patent performs preliminary action by forming sacrificial structures with the desired width variations before forming the actual word lines. The sacrificial structures are patterned with different widths for edge and central regions, and this preliminary patterning establishes the template for subsequent word line formation. The photomask is also prepared in advance with specific transparent and opaque portions to define the removal pattern.
Solution Approach 2:
The patent uses copying by transferring the width pattern from sacrificial structures to the final word lines. The sacrificial structures serve as templates that are copied onto the word line material through conformal deposition and etching processes. This copying approach ensures that the width variations defined in the sacrificial structures are accurately reproduced in the final word line structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively addresses current leakage by ensuring appropriate dimensions and reduced leakage paths, enhancing the electrical characteristics, quality, and yield of semiconductor structures while maintaining cost-effectiveness.
Implementation Method 1
arranging a photomask to cover the sacrificial structure, wherein the photomask includes a plurality of transparent portions and a plurality of opaque portions
Data Source
AI summary
A method of manufacturing a semiconductor structure and a semiconductor structure are provided. The method includes: providing a sacrificial structure disposed on a substrate; arranging a photomask to cover the sacrificial structure, wherein the photomask includes a plurality of transparent portions, a plurality of central opaque portions, at least one first edge opaque portion and at least one second edge opaque portion between the first edge opaque portion and the central opaque portions; removing portions of the sacrificial structure to form a plurality of central openings, at least one first edge opening and at least one second edge opening through the central opaque portions, the first edge opaque portion, the second edge opaque portion and the transparent portions; and forming at least one edge word line on the substrate through the second edge opening and forming a plurality of central word lines on the substrate through the central openings.