Contact Opening Profile for Lower-Resistance Semiconductor Interconnects

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Solution Overview

Problem

Existing semiconductor devices face challenges in achieving lower contact resistance, higher speed, and improved reliability due to limitations in contact area and design, particularly in the context of increasingly complex and miniaturized integrated circuits.

Innovation Solution

A directional etching process is employed to widen the upper portions of contact openings in semiconductor structures, enhancing the contact area with overlying metal lines while maintaining the lower portions within the time-dependent dielectric breakdown window requirements, thereby forming semiconductor devices with lower contact resistance and improved reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the contact area is increased to reduce contact resistance, then the contact resistance decreases and speed increases, but the device complexity and fabrication difficulty increase due to the need for precise control of contact opening dimensions

Engineering Contradiction:

Improvecontact resistanceVSAvoidcontact opening structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The contact opening is divided into two distinct portions: a lower portion with a first cross-sectional dimension and an upper portion with a second, larger cross-sectional dimension. This segmentation allows each portion to be optimized independently - the lower portion maintains precision for reliable electrical connection, while the upper portion provides increased contact area for lower contact resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the contact opening are given different dimensions and properties. The lower portion has a smaller cross-sectional dimension for precise alignment and connection, while the upper portion has a larger cross-sectional dimension for reduced contact resistance. This local differentiation resolves the contradiction between precision and contact area.

Inventive Principle:

Principle #3Local quality

2Reliability

If the contact opening dimensions are increased to reduce contact resistance, then the contact area increases and speed improves, but the manufacturing precision requirements become more stringent

Engineering Contradiction:

Improvecontact resistanceVSAvoidcontact opening dimension control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The contact opening is segmented into lower and upper portions with different cross-sectional dimensions. This allows the manufacturing process to apply different precision controls to different sections - the lower portion can be formed with tighter tolerances using standard processes, while the upper portion can be enlarged with less stringent precision requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The lower portion of the contact opening is formed first with precise dimensions, establishing a reliable foundation. Then the upper portion is subsequently enlarged to provide additional contact area. This preliminary formation of the critical lower portion ensures manufacturing precision is applied where it matters most.

Inventive Principle:

Principle #10Preliminary action

3Speed

If the contact area is enlarged to improve speed and reduce contact resistance, then the electrical performance improves, but the device complexity increases due to additional process steps

Engineering Contradiction:

Improvesignal transmission speedVSAvoidfabrication process

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The fabrication process is divided into sequential stages: first forming the lower contact opening portion, then subsequently enlarging the upper portion. This periodic, multi-stage approach allows complex geometry to be achieved through simple, repeated actions rather than a single complex process step.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The contact opening formation is segmented into distinct process stages corresponding to the lower and upper portions. This segmentation transforms a potentially complex single-step process into multiple simpler steps, each optimizing a specific portion of the contact opening.

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

The solution results in semiconductor devices with reduced contact resistance, increased speed, and enhanced reliability by optimizing the contact area through the directional etching process, addressing the limitations of existing technologies.

Implementation Method 1

A directional etching process is employed to widen the upper portions of contact openings in semiconductor structures

Methodology Applied

Scientific EffectDirectional etching:

Data Source

PatentUS12543556B2Semiconductor devices and methods of forming the same

Publication Date: 2026.02.03 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A method of forming a semiconductor device includes the following operations. A substrate is provided with an electric component. A composite dielectric layer is formed on the substrate and covers the electric component. An opening is formed through the composite dielectric layer. A directional etching process is performed to widen an upper portion of the opening. A metal feature is formed in the opening.