3DIC Die Bonding on Formed RDLs for Low-Thermal Packaging
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Solution Overview
Problem
Conventional semiconductor packaging methods face challenges in integrating increasing numbers of I/O pads into smaller areas, leading to difficulties in packaging and yield reduction due to high thermal budgets and the need for underfills, which can damage device dies.
Innovation Solution
The method involves forming Redistribution Lines (RDLs) on a carrier before bonding device dies, using hybrid bonding to reduce thermal stress and eliminate the need for underfills, and encapsulating the dies with a molding compound to create a thinner, more efficient package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If conventional packaging methods with high thermal budget processes are used, then I/O pads can be integrated into smaller areas, but device dies are damaged due to thermal stress
Solution Approach 1:
RDLs are formed on the molding compound before the device die is bonded to the package substrate. This preliminary formation of RDLs allows the device die to be bonded at lower temperatures, avoiding thermal stress damage, while still achieving the desired I/O pad integration density in the final package structure
Solution Approach 2:
Instead of forming RDLs after bonding the device die (conventional approach), the patent inverts the sequence by forming RDLs first on the molding compound, then bonding the device die. This inversion allows low-temperature bonding to protect the device die from thermal damage while achieving high I/O pad density
2Reliability
If conventional packaging with underfills is used, then device dies can be protected during bonding, but package thickness increases and manufacturing complexity rises
Solution Approach 1:
The patent eliminates the underfill step from the packaging process by forming RDLs on the molding compound before bonding. This extraction of the underfill requirement simplifies the manufacturing process, reduces package thickness, and maintains device die protection through the modified bonding sequence
Solution Approach 2:
RDLs are formed preliminarily on the molding compound before device die bonding, which eliminates the need for subsequent underfill application. This preliminary action simplifies the overall process by removing the underfill step while still providing adequate protection and structural support
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
This approach allows for thinner RDLs with smaller spacing, reduces thermal budget impact on device dies, and eliminates the need for underfills, resulting in improved packaging efficiency and yield.
Implementation Method 1
The device die is encapsulated in an encapsulating material
Implementation Method 2
performing a hybrid bonding to bond the device die to the dielectric layer and the plurality of bond pads
Data Source
AI summary
A method includes forming a dielectric layer over a carrier, forming a plurality of bond pads in the dielectric layer, and performing a planarization to level top surfaces of the dielectric layer and the plurality of bond pads with each other. A device die is bonded to the dielectric layer and portions of the plurality of bond pads through hybrid bonding. The device die is encapsulated in an encapsulating material. The carrier is then demounted from the device die and the dielectric layer.