Stacked Die Package Structure With Wavy Sidewalls for Plasma Dicing
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Solution Overview
Problem
As semiconductor devices shrink in size, challenges arise in efficiently singulating individual dies without causing damage, such as chipping or cracking, which affects yield and reliability, and traditional dicing methods are limited by blade-based processes.
Innovation Solution
A plasma dicing process is employed to create narrow, wavy-sided trenches that avoid direct contact with conductive features, using a photoresist pattern with wavy sidewalls to guide the etching, ensuring smooth separation of semiconductor dies with enhanced adhesion and reduced stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional blade-based dicing methods are used, then the dicing process is simple and fast, but the semiconductor dies suffer from chipping or cracking damage
Solution Approach 1:
The patent replaces the traditional mechanical blade-based dicing system with a plasma-based etching system. The plasma dicing process uses reactive ion etching to remove material and create separation trenches without mechanical contact, thereby eliminating chipping and cracking while maintaining process efficiency.
Solution Approach 2:
The patent changes the physical and chemical parameters of the dicing process by using plasma chemistry and controlled etching conditions instead of mechanical force. By adjusting plasma power, gas flow rates, and etching time, the process achieves precise material removal with minimal damage to the semiconductor dies.
2Productivity
If narrower dicing paths are used to increase throughput, then productivity increases, but the risk of damaging conductive features increases
Solution Approach 1:
The patent applies different etching conditions to different regions of the semiconductor wafer. The photoresist pattern with wavy sidewalls creates localized protection zones over conductive features, allowing the plasma to etch narrower paths in non-conductive areas while automatically avoiding conductive regions, thus enabling higher throughput without damaging sensitive features.
Solution Approach 2:
The patent introduces a photoresist pattern as an intermediary layer that guides the plasma etching process. This photoresist mask with wavy sidewalls acts as a protective intermediary that prevents direct plasma contact with conductive features while allowing precise definition of the dicing path, enabling narrower and safer trenches.
3Reliability
If photoresist pattern with wavy sidewalls is used to guide etching, then adhesion is enhanced and stress is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent employs photoresist patterns with wavy (curved) sidewalls instead of straight vertical walls. This curvature allows the etched trenches to follow a smoother path that naturally avoids sharp corners and stress concentration points, enhancing adhesion between the encapsulant and substrate while reducing mechanical stress in the final package structure.
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 plasma dicing process improves yield and reliability by minimizing damage, allowing for narrower dicing paths and increased throughput, while enhancing the adhesion and reducing stress-related issues in the packaging process.
Implementation Method 1
A plasma dicing process is employed to create narrow, wavy-sided trenches that avoid direct contact with conductive features
Implementation Method 2
using a photoresist pattern with wavy sidewalls to guide the etching
Data Source
AI summary
Provided are a package structure having stacked semiconductor dies with wavy sidewalls and a method of forming the same. The package structure includes: a first die and a second die bonded together; a first encapsulant laterally encapsulating the first die; and a second encapsulant laterally encapsulating the second die, wherein a second interface of the second die in contact with the second encapsulant is a wavy interface in a cross-sectional plane.