Trench Isolation Uniform Slope Formation
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Solution Overview
Problem
The trench isolation method in semiconductor devices faces challenges with uneven trench side surfaces and reduced width due to high integration, leading to difficulties in filling the isolation region with insulating material and the formation of voids.
Innovation Solution
A method involving the use of plasma to form a trench with uniform side surfaces by removing by-products and native oxide layers, employing a dry etching process with specific gas combinations and power settings to prevent ledge formation and ensure uniformity, allowing for defect-free gap filling with insulating material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the trench width is reduced due to high integration, then device isolation density increases, but it becomes more difficult to fill the trench with insulating material and voids are generated
Solution Approach 1:
The patent applies preliminary action by performing a plasma treatment step before the etching process to remove organic by-products and native oxide from the substrate surface. This preliminary cleaning ensures that the subsequent etching process creates clean trench walls that facilitate complete insulating material filling without void formation, even in narrow trenches required for high integration.
Solution Approach 2:
The patent utilizes parameter changes by adjusting plasma process parameters (power, pressure, gas composition) to achieve optimal removal of organic by-products and native oxide. By controlling the plasma treatment conditions, the method achieves uniform surface preparation that enables successful filling of narrow trenches while maintaining high device isolation density.
2Ease of manufacture
If conventional etching is used to form trenches, then the etching process is simple, but ledges are formed on the trench top edge and side surfaces become uneven
Solution Approach 1:
The patent applies preliminary action by performing plasma treatment before etching to remove organic by-products that would otherwise interfere with the etching process. This preliminary step prevents the formation of ledges and uneven surfaces during etching, achieving uniform trench side surfaces while maintaining process simplicity.
Solution Approach 2:
The patent replaces conventional mechanical/chemical etching alone with a plasma-based process that uses ion bombardment and chemical reactions. This substitution enables precise control over the etching mechanism, producing uniform trench side surfaces without ledges while maintaining ease of manufacture through a single integrated process step.
3Productivity
If organic by-products remain on the substrate during mask pattern formation, then the process is faster, but ledges are formed and trench side surfaces become uneven
Solution Approach 1:
The patent applies preliminary action by incorporating plasma treatment as a preparatory step before mask pattern formation and etching. This preliminary removal of organic by-products prevents their accumulation during subsequent processes, ensuring uniform trench side surfaces without sacrificing overall process productivity through efficient plasma cleaning.
Solution Approach 2:
The patent converts the potentially harmful effect of organic by-product accumulation into a benefit by using plasma treatment to deliberately remove these by-products. The plasma process transforms the presence of organic contaminants (which would cause ledges and uneven surfaces) into a controlled cleaning step that actually improves trench side surface uniformity while maintaining productivity.
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 method achieves uniform trench formation and defect-free filling with insulating material, even at reduced trench widths, enhancing device isolation and reducing voids in high-integration semiconductor devices.
Implementation Method 1
using plasma to at least partially remove a by-product produced during formation of the mask pattern
Implementation Method 2
etching the exposed substrate to form a trench having side surfaces including a uniform slope
Data Source
AI summary
Provided herein are methods of forming a trench including forming a mask layer on a substrate, forming a mask pattern to expose the substrate, using plasma to at least partially remove by-products produced during formation of the mask pattern; and etching the exposed substrate to form a trench having side surfaces including a uniform slope.