Via Formation Between Inductor and MIM Capacitor

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Solution Overview

Problem

The challenge in forming a via between an inductor and a metal-insulator-metal (MIM) capacitor leads to undesirable eddy currents and potential burnout of the MIM capacitor due to etching limitations and deposition variations, resulting in inconsistent via depths and excessive etching that can damage the capacitor.

Innovation Solution

Incorporating a middle etch stop layer between the first and second via dielectric layers to control the over-etching process, ensuring that the via holes are formed without exceeding the thickness of the etch stop layers, thereby preventing damage to the capacitor and improving the formation of vias between the inductor and the MIM capacitor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a via is formed between the inductor and MIM capacitor using conventional etching processes, then the via connects the two components electrically, but the etching process causes over-etching that damages the MIM capacitor

Engineering Contradiction:
Improvevia formation reliabilityVSAvoidcapacitor burnout from over-etching
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An etch stop layer is introduced as an intermediary component between the via dielectric layer and the MIM capacitor. This etch stop layer acts as a protective mediator that stops the etching process before it reaches the capacitor, preventing over-etching damage while still allowing via formation to proceed

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The etch stop layer is deposited beforehand as a cushioning protective layer. This layer provides a safety margin that absorbs the over-etching process, ensuring that even if the etching continues beyond the intended depth, the capacitor remains protected from damage

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Manufacturing precision

If the etching process is extended to ensure via depth consistency, then via depth uniformity improves, but the risk of capacitor damage increases

Engineering Contradiction:
Improvevia depth consistencyVSAvoidcapacitor integrity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The etch stop layer serves as a mediator that decouples the via depth control from the capacitor protection. It allows the etching process to continue uniformly to achieve consistent via depths while the etch stop layer prevents the process from damaging the capacitor

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The etch stop layer provides beforehand cushioning that enables aggressive etching for depth consistency without risking capacitor damage. The cushioning layer absorbs the excess etching, allowing manufacturing precision to be improved without sacrificing reliability

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If no etch stop layer is used to simplify the process, then manufacturing complexity decreases, but via depth control and capacitor protection are compromised

Engineering Contradiction:
Improvevia formation process complexityVSAvoidvia depth control
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The etch stop layer is a simple intermediary that adds minimal complexity to the process structure. It is deposited as an additional layer but requires no complex process changes, providing via depth control and capacitor protection with minimal increase in manufacturing complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentUS9362222B2Interconnection between inductor and metal-insulator-metal (MIM) capacitor
Publication Date: 2016.06.07 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Embodiments of mechanisms for forming a semiconductor device structure are provided. The semiconductor device structure includes a metal-insulator-metal (MIM) capacitor formed on a substrate. The semiconductor device structure also includes an inductor formed on the MIM capacitor. The semiconductor device structure further includes a via formed between the MIM capacitor and the inductor, and the via is formed in a plurality of dielectric layers, and the dielectric layers comprise an etch stop layer.