Semiconductor Gate Structure With Cap Layer Etching Stop
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Solution Overview
Problem
The challenge in semiconductor manufacturing is achieving accurate scaling of semiconductor structures, such as transistors or memory arrays, as the line width shrinks, requiring precise processes to prevent efficiency losses due to process shifts or side effects during manufacturing.
Innovation Solution
A semiconductor structure comprising a substrate, a gate structure with a cap layer, and a conductive element, where the conductive element has a lower and upper portion with an interface below the cap layer, and a method involving etching steps with the cap layer as an etching stop layer to form openings for the conductive portions, allowing for higher device density and improved operating efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the line width of semiconductor process is shrunk to scale down the semiconductor structure, then the device density is improved, but the manufacturing precision requirement increases and process shifts cause efficiency loss
Solution Approach 1:
The cap layer is formed on the gate electrode before the conductive element formation process. This preliminary action establishes a reference structure that guides subsequent etching steps, ensuring that openings are formed at precise locations relative to the gate electrode, thereby maintaining manufacturing precision while enabling scaled-down device dimensions
Solution Approach 2:
The cap layer serves as an intermediary etching stop layer between the etching process and the gate electrode. It mediates the etching process by providing a controlled stopping point, which ensures precise positioning of the conductive element openings relative to the gate structure, thus maintaining manufacturing accuracy at scaled dimensions
2Reliability
If the upper conductive portion is positioned closer to the lower conductive portion, then the resistance is reduced and operating efficiency is improved, but the risk of process shift and side effects increases
Solution Approach 1:
The cap layer acts as an intermediary etching stop layer that enables precise control of the opening position. By providing a well-defined reference plane for the etching process, it allows the upper and lower conductive portions to be positioned closer together (reducing resistance) while maintaining precise alignment control that tolerates process variations
Solution Approach 2:
The patent replaces traditional mechanical alignment methods with a self-aligned approach using the cap layer as an etching stop. This substitution enables more precise positioning of conductive elements closer together, reducing resistance while the cap layer's controlled etching stop provides tolerance against process shifts
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 enables higher device density and improved operating efficiency by ensuring the upper conductive portion is closely positioned to the lower conductive portion, reducing resistance and avoiding additional area occupation outside the active region, thus enhancing semiconductor device performance.
Implementation Method 1
a cap layer on the gate electrode is functioned as an etching stop layer for the etching step
Data Source
AI summary
A semiconductor structure and a method for forming the same are provided. The semiconductor structure includes a substrate, a gate structure, and a conductive element. The gate structure is on the substrate. The gate structure includes a gate electrode and a cap layer on the gate electrode. The conductive element is adjoined with an outer surface of the gate structure. The conductive element includes a lower conductive portion and an upper conductive portion electrically connected on the lower conductive portion and adjoined with the cap layer. The lower conductive portion and the upper conductive portion have an interface therebetween. The interface is below an upper surface of the cap layer.