Stress Reduction Structure for MIM Capacitors
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in preventing stress-induced damage and cracks in metal-insulator-metal (MIM) capacitors, which are critical components in advanced integrated circuits, due to induced stress from surrounding layers and features.
Innovation Solution
A stress-reduction feature is embedded within a passivation layer over MIM capacitors, comprising a multi-layer structure with an oxygen-containing layer between nitrogen-containing layers, functioning as a crack stop to prevent stress propagation and damage, specifically a nitrogen-oxygen-nitrogen (NON) multi-layer structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If passivation layers and contact pads are formed over MIM capacitors, then device integration and interconnection are achieved, but stress is induced on the MIM capacitors causing damage and cracks
Solution Approach 1:
The passivation layer is segmented into multiple layers with different material compositions and stress characteristics. By dividing the single passivation layer into upper and lower passivation layers with an intermediate layer, the overall stress on the MIM capacitor is distributed and reduced, preventing stress-induced damage while maintaining device integration
Solution Approach 2:
The patent employs composite material structures where the passivation system consists of multiple materials with different mechanical properties. The lower passivation layer may include silicon nitride (compressive stress), the intermediate layer may include silicon oxide (tensile stress), and the upper passivation layer may include silicon nitride or other dielectric materials. This composite structure creates a stress-balanced system that protects the MIM capacitor
2Ease of operation
If surrounding layers and contact pads are added to MIM capacitors, then functional interconnection is provided, but stress propagation and crack formation occur
Solution Approach 1:
An intermediate layer is introduced between the upper and lower passivation layers to act as a stress mediator. This intermediate layer, composed of materials such as silicon oxide, has different stress characteristics that help to decouple and reduce stress propagation from the upper passivation and contact structures down to the MIM capacitor, while still allowing functional interconnection
Solution Approach 2:
The patent changes the material composition and thickness parameters of the passivation layers to control stress characteristics. By adjusting the thickness ratios and material compositions (e.g., silicon nitride vs. silicon oxide), the stress state is modified to minimize tensile stress on the MIM capacitor, thereby preventing crack formation while maintaining interconnection functionality
Data Source
AI summary
A method and semiconductor device including a substrate having one or more semiconductor devices. In some embodiments, the device further includes a first passivation layer disposed over the one or more semiconductor devices. The device may further include a metal-insulator-metal (MIM) capacitor structure formed over the first passivation layer. In addition, the device may further include a second passivation layer disposed over the MIM capacitor structure. In various examples, a stress-reduction feature is embedded within the second passivation layer. In some embodiments, the stress-reduction feature includes a first nitrogen-containing layer, an oxygen-containing layer disposed over the first nitrogen-containing layer, and a second nitrogen-containing layer disposed over the oxygen containing layer.