Trench Fabrication via Sacrificial Layer Alignment
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Solution Overview
Problem
The challenge in semiconductor manufacturing lies in fabricating trenches with high aspect ratios, which poses difficulties in processing precision and increases product defect risks due to the complexity of existing trench fabrication processes.
Innovation Solution
A trench fabrication method involving sequential deposition and etching of dielectric layers, with the formation of a sacrificial layer to facilitate the creation of trenches with varying widths, enhancing precision and yield by ensuring effective communication between the trenches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional single-step etching is used to fabricate high aspect ratio trenches, then the chip area can be reduced, but the manufacturing precision deteriorates and defect risks increase
Solution Approach 1:
The patent divides the single-step etching process into multiple sequential etching steps with different etching depths. The first etching step forms a first trench to a first etching depth, and the second etching step forms a second trench to a second etching depth that is greater than the first etching depth. This segmentation allows each etching step to operate within optimal precision parameters while achieving the overall high aspect ratio trench structure, thereby maintaining manufacturing precision despite the reduced chip area.
2Productivity
If conventional single-step etching is used for high aspect ratio trenches, then processing speed is maintained, but the device complexity increases due to precision control difficulties
Solution Approach 1:
The patent applies preliminary action by forming a sacrificial layer in the first trench before the second etching step. This sacrificial layer serves as a temporary structure that guides and simplifies the second etching process. By preparing this intermediate structure in advance, the complex precision control required for high aspect ratio trenches is transformed into a more manageable multi-step process with clear intermediate targets, reducing overall process complexity while maintaining productivity.
3Ease of manufacture
If conventional etching processes are used, then the fabrication process remains simple, but the reliability of high aspect ratio trenches deteriorates due to offset defects
Solution Approach 1:
The patent introduces a sacrificial layer as an intermediary element between the first and second etching steps. This sacrificial layer acts as a mediator that ensures precise alignment and communication between the first trench and second trench. By using this intermediary structure, the reliability of high aspect ratio trench fabrication is improved as it prevents offset defects and ensures proper trench formation, while the overall fabrication process remains relatively simple and manageable.
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
This method simplifies the fabrication process, improves precision, reduces defect risks, and increases product yield by allowing for the creation of trenches with high aspect ratios through step-by-step deposition and etching, ensuring effective communication between the trenches.
Implementation Method 1
subjecting a photoresist to photolithographic exposure by photolithography
Implementation Method 2
removing unwanted parts of the photoresist through corrosion
Data Source
AI summary
Provided is a trench fabrication method including: forming a first dielectric layer on a semiconductor substrate; patterning/etching the first dielectric layer to form a first trench; forming a sacrificial layer for filling the first trench; forming a second dielectric layer for covering the first dielectric layer and the sacrificial layer; etching the second dielectric layer to form a second trench for exposing the sacrificial layer; and removing the sacrificial layer to form a trench whereby the first trench and the second trench are aligned and connected with each other. The trench fabrication method involves effecting deposition step by step and etching the dielectric layers step by step, so as to fabricate a trench with a high aspect ratio, render the fabrication process simple and easy, enhance process precision, reduce product defect risks, and increase product yield.