Selective Metal Growth for Semiconductor Plug Formation

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Solution Overview

Problem

Current semiconductor structures face performance issues due to poor etching processes that result in height differences and residue formation between plugs, leading to increased contact resistance and reduced semiconductor performance.

Innovation Solution

A method involving a selective metal growth process to form plugs in through holes, where the plugs grow from the bottom, reducing height differences and residue formation, and using the same materials for both metal structures to minimize growth rate disparities and residue formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional etching process is used to form openings and deposit conductive material, then electrical connection structures can be formed, but height differences and residue formation occur between plugs leading to increased contact resistance

Engineering Contradiction:

Improvecontact resistanceVSAvoidplug height uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the fundamental parameter of plug formation from conventional etching followed by deposition to selective metal growth. This parameter change enables the metal to grow selectively from the bottom of through-holes, ensuring uniform plug heights and eliminating residue formation on the device layer, thereby reducing contact resistance and improving reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Instead of forming plugs by depositing material from the top surface (conventional approach), the patent inverts the process by having metal grow from the bottom of through-holes upward. This inversion ensures that plugs reach uniform heights and prevents residue formation, directly addressing the manufacturing precision and reliability issues

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If different materials are used for first and second metal structures, then device functionality can be achieved, but growth rate disparities occur during selective metal growth process

Engineering Contradiction:

Improvedevice functionalityVSAvoidplug height uniformity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by using the same metal material (such as cobalt or tungsten) for both first and second metal structures in regions where selective growth is performed. This ensures uniform growth rates during the selective metal growth process, maintaining plug height uniformity while still allowing different materials to be used in other device regions for specific functionality

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If selective metal growth process is used to form plugs, then residue formation is reduced and plug quality is improved, but process complexity increases

Engineering Contradiction:

Improveplug qualityVSAvoidfabrication process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The selective metal growth process is a self-service process where the metal automatically grows from the bottom of through-holes to the top, filling them completely without requiring additional deposition steps or planarization processes. This self-filling mechanism simplifies the overall fabrication process despite the specialized growth conditions, while delivering superior plug quality with no residue formation

Inventive Principle:

Principle #25Self-service

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 reduces residue formation on the device layer, improves plug quality, and decreases contact resistance, enhancing the overall performance of the semiconductor structure.

Implementation Method 1

using a selective metal growth process, forming a first plug in the first through hole and forming a second plug in the second through hole

Methodology Applied

Scientific EffectSelective metal growth:

Data Source

PatentUS11587848B2Forming metal plug through a hole in a device including a resistance layer and contacting embedded conductive structures

Publication Date: 2023.02.21 SEMICON MFG INT (SHANGHAI) CORP

AI summary

Semiconductor structure and its fabrication method are provided. The method includes providing a substrate, where the substrate includes a first region having a first metal structure and a second region having a second metal structure; forming a device layer on each of top surfaces of the substrate, the first metal structure and the second metal structure; forming a first through hole in the device layer at the first region, where the first through hole exposes at least a portion of surfaces of the first metal structure, and forming a second through hole in the device layer at the second region, where the second through hole passes through the first device and exposes at least a portion of surfaces of the second metal structure; and using a selective metal growth process, forming a first plug in the first through hole and forming a second plug in the second through hole.