Semiconductor Trench Isolation via Segmented Insulating Films

Solution Overview

Problem

In semiconductor device manufacturing, forming insulating films in high aspect ratio trenches using silicon oxide by CVD often results in uneven thickness, leading to defects and performance deterioration due to difficulty in precisely adjusting the closing position of the trench, causing polishing slurry or washing liquids to enter and become foreign matter.

Innovation Solution

A semiconductor device with a first insulating film containing silicon and oxygen, a second insulating film made of a different material, and a third insulating film used to close the trench while leaving a space inside, with specific opening widths and trench widths to control the closing position and prevent exposure during planarization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an insulating film is formed from silicon oxide by CVD to close the trench portion, then the trench portion can be closed while leaving a space inside, but the thickness of the insulating film becomes uneven and the closing position cannot be precisely adjusted

Engineering Contradiction:

Improveelement isolation characteristicsVSAvoidclosing position accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The insulating film formation process is segmented into multiple steps: first forming a preliminary insulating film to close the trench portion and leave a space, then forming a planarization insulating film on top. This segmentation allows the closing position to be precisely controlled by the preliminary film while the planarization film ensures uniform surface for subsequent processing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The preliminary insulating film is formed first to establish the closing position of the trench portion before the planarization insulating film is added. This preliminary action ensures that the space inside the trench is properly defined and sealed at the correct height, preventing slurry or washing liquid from entering.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the closing position of the space is set too high in the trench portion, then the trench can be effectively closed, but polishing slurry or washing liquid may enter the exposed space and become foreign matter causing defects

Engineering Contradiction:

Improveelement isolation characteristicsVSAvoidforeign matter contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The preliminary insulating film is formed first to establish the closing position of the trench portion before the planarization insulating film is added. This preliminary action ensures that the space inside the trench is properly defined and sealed at the correct height, preventing slurry or washing liquid from entering.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The planarization insulating film acts as an intermediary layer that covers and protects the space inside the trench portion. This intermediary layer prevents polishing slurry and washing liquid from directly contacting and entering the space, eliminating the source of foreign matter contamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the insulating film thickness on the side surface is greater than on the bottom surface, then the trench portion can be closed while leaving a space, but it becomes difficult to precisely control the closing position

Engineering Contradiction:

Improveelement isolation characteristicsVSAvoidclosing position control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The insulating film formation process is segmented into multiple steps: first forming a preliminary insulating film to close the trench portion and leave a space, then forming a planarization insulating film on top. This segmentation allows the closing position to be precisely controlled by the preliminary film while the planarization film ensures uniform surface for subsequent processing.

Inventive Principle:

Principle #1Segmentation

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 approach improves element isolation characteristics, reduces leakage current, increases breakdown voltage, and enhances the accuracy of contact hole formation, preventing defects and improving the overall performance of the semiconductor device.

Implementation Method 1

forming an insulating film in a trench portion having a high aspect ratio, the trench portion is sometimes closed by an insulating film formed from a silicon oxide, for example, by chemical vapor deposition (CVD)

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Data Source

PatentUS10096510B2Semiconductor device and method of manufacturing same

Publication Date: 2018.10.09 RENESAS ELECTRONICS CORP

AI summary

To provide a semiconductor device having improved performance. The semiconductor device has a first insulating film formed on the main surface of a semiconductor substrate and a second insulating film formed on the first insulating film. The semiconductor device further has a first opening portion penetrating through the second insulating film and reaching the first insulating film, a second opening portion penetrating through the first insulating film and reaching the semiconductor substrate, and a trench portion formed in the semiconductor substrate. A first opening width of the first opening portion and a second opening width of the second opening portion are greater than a trench width of the trench portion. The trench portion is closed by a third insulating film while leaving a space in the trench portion.