Semiconductor Device Uniform Metal Fill via Polymer Gas Etching

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Solution Overview

Problem

Conventional semiconductor fabrication processes result in varying channel depths and metal fill amounts between different regions, leading to degraded electrical performance due to differences in active region widths and channel depths.

Innovation Solution

A semiconductor device and fabrication method where protruding portions on a substrate define dense and loose zones, with a word line disposed on the substrate, and the use of polymer gases like C4F6, CH2F2, or CHF3 during etching to ensure the bottom surfaces of metal-filled trenches in both zones are at the same height, maintaining consistent metal thickness and depth across zones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional fabrication process is used with alternatively arranged active regions of different widths, then device structure complexity is reduced, but manufacturing precision deteriorates due to varying channel depths and metal fill amounts

Engineering Contradiction:

Improvestructure complexityVSAvoidchannel depth uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by introducing polymer gas during etching to create different etching rates in dense zones versus loose zones. This results in locally adapted trench depths that compensate for the varying active region widths, ensuring uniform metal fill depth across all regions while maintaining the simple alternatively arranged structure.

Inventive Principle:

Principle #3Local quality

2Device complexity

If conventional etching process is used without polymer gas, then manufacturing process complexity is reduced, but manufacturing precision deteriorates due to non-uniform trench depths

Engineering Contradiction:

Improveetching process complexityVSAvoidtrench depth uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent changes the etching process parameters by introducing polymer gas (C4F6, CH2F2, or CHF3) at controlled flow rates (1-3 sccm). This parameter change modifies the etching chemistry to achieve different etching rates in different zones, resulting in uniform trench depths despite varying active region widths.

Inventive Principle:

Principle #35Parameter changes

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 the electrical performance of the semiconductor device by ensuring uniform metal fill across different zones, enhancing the device's conductivity and reliability.

Implementation Method 1

forming the trench is performed by etching

Methodology Applied

Scientific EffectEtching:

Implementation Method 2

adding polymer gas, and the polymer gas comprises at least one of the C4F6, CH2F2, CHF3, or any combination thereof

Methodology Applied

Scientific EffectPolymer gas deposition: Deposition (physical)

Data Source

PatentUS11488961B2Semiconductor device

Publication Date: 2022.11.01 NAN YA TECH

AI summary

A semiconductor device includes a substrate, an oxide layer and a word line. The substrate has a plurality of protruding portions. Adjacent two of the protruding portions define a dense zone, and another adjacent two of the protruding portions define a loose zone. The oxide layer is disposed on the substrate. The word line is disposed on the substrate. A bottom surface of a portion of the word line in the dense zone and a bottom surface of a portion of the word line in the loose zone are substantially at the same height.