Metal Segments as Landing Pads for IC Via Alignment

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Solution Overview

Problem

In integrated circuit (IC) devices, misalignment between vias and contact surfaces leads to unreliable connections, affecting device functionality and manufacturing yield, particularly at 7 nanometer technology nodes and beyond.

Innovation Solution

Utilizing metal segments of an additional metal layer as landing pads for vias and local interconnects between contacts, which provides a larger contact area and improves alignment, thereby enhancing connection reliability without increasing chip area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If vias are used to connect metal layers to contacts, then electrical connection is achieved, but misalignment between via and contact reduces connection reliability

Engineering Contradiction:

Improveconnection reliabilityVSAvoidvia-contact alignment precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent introduces an intermediate metal segment layer between the via and the contact. This intermediate layer acts as a mediator that compensates for misalignment, allowing the via to connect to the metal segment which in turn connects to the contact, thereby ensuring reliable electrical connection even when precise alignment is difficult to achieve

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The connection path is divided into multiple segments: via connecting to metal segment, and metal segment connecting to contact. This segmentation allows each component to be optimized independently and provides flexibility in accommodating alignment variations

Inventive Principle:

Principle #1Segmentation

2Reliability

If contact area is increased to improve connection reliability, then connection strength improves, but chip area increases

Engineering Contradiction:

Improveconnection reliabilityVSAvoidchip area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent utilizes the vertical dimension by introducing an additional metal layer between the via and contact. Instead of expanding the contact area in the horizontal plane, the solution extends the connection path vertically through the metal segment layer, thereby improving connection reliability without increasing chip area

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS9466604B2Metal segments as landing pads and local interconnects in an IC device

Publication Date: 2016.10.11 GLOBALFOUNDRIES US INC

AI summary

Methods for utilizing metal segments of an additional metal layer as landing pads for vias and also as local interconnects between contacts in an IC device and resulting devices are disclosed. Embodiments include forming source/drain and gate contacts connected to transistors on a substrate in an integrated circuit device, each contact having an upper surface with a first area; forming metal segments in a plane at the upper surface of the contacts, each metal segment being in contact with one or more of the contacts and having a second area greater than the first area; and forming one or more vias between one or more of the metal segments and one or more first segments of a first metal layer.