Wafer Bonding Thermal Paths for IC Package Heat Dissipation
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Solution Overview
Problem
Current wafer bonding techniques fail to effectively enhance thermal conductivity in integrated circuit packages, leading to inefficient heat dissipation in device wafers.
Innovation Solution
The formation of thermal conductive channels in both device and carrier wafers, using materials like copper, aluminum, and nickel, which are bonded together to improve heat dissipation through direct metal-to-metal bonding or physical contact, allowing heat generated in device dies to be conducted efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional wafer bonding techniques are used, then device wafers can be bonded to carrier wafers for thinning and electrical connector formation, but thermal conductivity in the integrated circuit packages is insufficient leading to inefficient heat dissipation
Solution Approach 1:
The patent divides the thermal management function into separate thermal conductive channels formed in both the device wafer and carrier wafer. These channels are created as distinct segmented structures that penetrate through the wafers and bond together, allowing heat to be conducted through dedicated pathways rather than relying on the bulk material's thermal conductivity.
Solution Approach 2:
The patent introduces thermal conductive channels as intermediary structures that facilitate heat transfer between the device wafer and carrier wafer. These channels act as thermal mediators, providing a low-resistance path for heat flow through the bond interface, thereby improving overall thermal conductivity without requiring the base materials to have high intrinsic thermal conductivity.
2Reliability
If thermal conductive channels are formed in both device and carrier wafers using direct metal-to-metal bonding, then thermal conductivity is significantly enhanced, but the manufacturing process complexity increases
Solution Approach 1:
The patent performs preliminary actions by forming the thermal conductive channels in both the device wafer and carrier wafer before the bonding step. The channels are pre-formed with bonding surfaces that will directly contact each other during wafer bonding, eliminating the need for complex post-bonding thermal path creation and simplifying the overall manufacturing sequence.
Solution Approach 2:
The patent merges multiple functions into the thermal conductive channels: they serve as both thermal conduction pathways and bonding interfaces. By combining the thermal management function with the structural bonding function, the patent reduces the need for separate components and simplifies the manufacturing process despite the enhanced thermal conductivity requirement.
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 significantly enhances the thermal conductivity of the resulting package, effectively dissipating heat generated in device dies to underlying structures, thereby improving heat management in integrated circuit packages.
Implementation Method 1
The device wafer is bonded to the carrier wafer, with the first thermal conductive channel at least in physical contact with the second thermal conductive channel... the heat generated in the device die may be conducted through the thermal conductive channels
Data Source
AI summary
A method includes forming a first bond layer on a first wafer, and forming a first thermal conductive channel extending into the first bond layer. The first thermal conductive channel has a first thermal conductivity value higher than a second thermal conductivity value of the first bond layer. The method further includes forming a second bond layer on a second wafer, and forming a second thermal conductive channel extending into the second bond layer. The second thermal conductive channel has a third thermal conductivity value higher than a fourth thermal conductivity value of the second bond layer. The first wafer is bonded to the second wafer, and the first thermal conductive channel at least physically contacts the second thermal conductive channel. An interconnect structure is formed over the first wafer. The interconnect structure is electrically connected to integrated circuit devices in the first wafer.