Semiconductor Contact Formation via Curved Recess Etching

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Solution Overview

Problem

The formation of contacts in semiconductor structures is non-uniform due to uneven recesses from the etching process, leading to lower throughput and performance.

Innovation Solution

A method involving the formation of recesses with curved top surfaces that are later modified to have top and sidewalls substantially perpendicular to each other, allowing for the creation of contacts with perpendicular surfaces, which are then cleaned and filled with conductive materials, enhancing growth rate and uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional etching process is used to form recesses, then contacts can be formed, but the recesses are non-uniform resulting in non-uniform contacts and lower throughput

Engineering Contradiction:

Improveuniformity of contactsVSAvoidthroughput of contacts

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by performing a first etching process to create recesses with curved top surfaces before the contact formation process. This preliminary shaping of the recesses ensures that when contacts are subsequently formed, they grow uniformly from a pre-conditioned surface, thereby achieving both uniform contacts and high throughput without requiring re-etching or adjustment during contact formation

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If etching process forms recesses with curved top surfaces, then contact formation is enabled, but the curved surfaces cause non-uniform contact formation reducing performance

Engineering Contradiction:

Improvecontact formation capabilityVSAvoidperformance of semiconductor structure

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent segments the contact formation process into distinct stages: first forming recesses with curved top surfaces, then performing a second etching process to create recesses with substantially perpendicular sidewalls and flat bottom surfaces, and finally forming contacts. This segmentation allows each stage to be optimized independently, ensuring both ease of manufacture and high reliability by eliminating the performance-degrading effect of curved surfaces

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 results in higher throughput and improved performance of semiconductor contacts by ensuring uniform formation and increased growth rate, thereby enhancing the overall semiconductor structure.

Implementation Method 1

The active regions are etched to form recesses with curved top surfaces

Methodology Applied

Scientific EffectEtching:

Implementation Method 2

etching the active regions again to change each of the curved top surfaces is performed by wet etching

Methodology Applied

Scientific EffectWet etching:

Implementation Method 3

performing a clean treatment on the top surfaces and the sidewalls of the active regions before forming the contacts

Methodology Applied

Scientific EffectClean treatment:

Data Source

PatentUS11538912B2Method of forming semiconductor structure

Publication Date: 2022.12.27 NAN YA TECH

AI summary

A method of forming a semiconductor structure includes following steps. A first isolation is formed between a pair of active regions. A gate structure is formed on the first isolation structure. The active regions are etched to form recesses with curved top surfaces. The active regions are etched again to change each of the curved top surfaces to be a top surface and a sidewall substantially perpendicular to the top surface. A pair of contacts is formed respectively on the active regions, such that each of the contacts has a bottom surface and a sidewall substantially perpendicular to the bottom surface.