Dummy Metal Structures for Stress Management in Semiconductor Devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Low dielectric constant insulating films in semiconductor devices suffer from poor adhesion and mechanical strength, leading to cracking during dicing, which damages the circuit and reduces assembly yield due to uncontrolled stress propagation and metal rupture.
Innovation Solution
The implementation of a semiconductor device design featuring a multilayer interconnect structure with strategically placed dummy metal structures that convert horizontal stress to vertical stress, allowing for angular deformation and release of stress upward, preventing crack propagation and ensuring assembly reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If low dielectric constant insulating film is used to improve performance, then device performance is improved, but adhesion strength and mechanical strength deteriorate
Solution Approach 1:
Dummy metal structures are formed in advance in the low-k insulating film before dicing to preemptively manage stress concentration points. These dummy structures serve as stress release mechanisms that prevent crack initiation and propagation during the subsequent dicing process, thereby preserving the integrity of the low-k film while maintaining device performance.
2Reliability
If dummy via is formed over the whole layers to prevent crack propagation, then crack propagation is prevented, but stress release becomes difficult and metal rupture occurs
Solution Approach 1:
Instead of uniformly distributing dummy vias across all layers, the invention selectively places dummy metal structures only in specific regions where stress concentration is most critical during dicing. This localized approach allows stress to be released at controlled points without creating metal rupture, thereby maintaining both crack prevention and stress release capabilities.
3Manufacturing precision
If grooves are provided in scribe line to prevent chipping, then chipping is reduced, but chipping fragments still force inward and damage inside film during dicing
Solution Approach 1:
The dummy metal structures act as intermediary elements between the scribe line grooves and the inside film. When chipping fragments are generated during dicing, the dummy metal structures intercept and absorb the fragments before they can force inward and damage the inside film, thereby protecting the circuit forming region from fragment-induced damage.
Data Source
AI summary
A semiconductor device includes a seal ring formed on an outer circumference of an element forming region when seen from the top in a multilayer interconnect structure formed on a silicon layer, and dummy metal structures formed on a further outer circumference of the seal ring. The more inner circumference side the dummy interconnect is formed on, the more upper layer the dummy interconnect is arranged on.