Water Cooled Server Modules With Flip-Chip Substrates
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Solution Overview
Problem
Current water-cooled servers face challenges in achieving high power density and manufacturability due to the space occupation by packaged devices and heat sinks, and the need for efficient cooling solutions.
Innovation Solution
The design incorporates a substrate with redistribution layers and flip-chip mounted electronic components, surrounded by a three-sided copper enclosure sealed against water intrusion, allowing for high-power density operation and efficient cooling by circulating water between modules, with redundant components and agile reconfiguration for fault tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If packaged devices with heat sinks are used, then cooling capability is improved, but device volume and space occupation increase significantly
Solution Approach 1:
The invention extracts the heat dissipation function from traditional packaged devices with heat sinks and relocates it to a separate liquid cooling system. The chips are mounted in a liquid-filled enclosure where cooling liquid directly contacts the chip surfaces, separating the computational function from the thermal management function and eliminating the need for bulky heat sinks attached to each device.
Solution Approach 2:
The invention merges multiple chips and their cooling requirements into a single integrated liquid-filled enclosure. Instead of individual cooling solutions for each chip, the enclosure combines multiple chips with a shared liquid cooling environment, reducing overall system volume while maintaining effective heat dissipation for all components.
2Power
If high-power chips are used, then processing power is improved, but heat generation and cooling requirements increase
Solution Approach 1:
The invention uses liquid hydraulics to transfer heat away from high-power chips. A liquid cooling system with circulating coolant directly contacts the chip surfaces in the enclosure, efficiently carrying away generated heat through fluid convection and phase change, enabling sustained high-power operation without excessive temperature rise.
Solution Approach 2:
The liquid cooling system utilizes phase transitions of the cooling liquid (evaporation and condensation) to absorb and remove heat from the high-power chips. As the coolant contacts the hot chip surfaces, it undergoes phase change from liquid to vapor, absorbing large amounts of latent heat, then condenses back to liquid in heat exchangers, creating an efficient thermal management cycle for high-power devices.
3Ease of manufacture
If traditional mounting methods are used, then manufacturing simplicity is maintained, but power density and space efficiency decrease
Solution Approach 1:
The invention segments the system into standardized modules: substrates with chip mounting areas, liquid-filled enclosures with integrated cooling, and interchangeable chip cartridges. This modular segmentation maintains manufacturing simplicity through standardized processes while enabling high power density through efficient space utilization in each module and across the system.
Solution Approach 2:
The invention transitions from traditional two-dimensional planar mounting to three-dimensional vertical stacking within the liquid enclosure. Chips are mounted on substrates that can be stacked vertically, with cooling liquid flowing through channels between layers,充分利用 three-dimensional space to achieve high power density while maintaining standardized manufacturing processes for each layer.
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 configuration achieves a power density of 500-1500 watts per cubic inch and efficient cooling, reducing the need for customized heat sinks and enhancing manufacturability with regularized electronic structures, while maintaining system reliability and adaptability.
Implementation Method 1
Copper sheets are bonded to the polished planar surfaces on each side of the substrate using a thermal interface material (TIM)
Implementation Method 2
efficient cooling by circulating water between modules
Implementation Method 3
Copper sheets are bonded to the polished planar surfaces on each side of the substrate using a thermal interface material (TIM)
Data Source
AI summary
A computer module includes a substrate having redistribution layers comprising conductors and dielectrics formed on both sides of the substrate. Selected thin film conductors have a half pitch of 2 μm or less. Semiconductor components selected from bare die, chiplets, stacked devices, and low-profile packaged devices are flip chip mounted on the substrate. After grinding and polishing operations, a polished planar surface extends across each side of the substrate, coincident with the back side of the semiconductor components. Copper sheets are bonded to the polished planar surfaces using die attach films. A water-cooled server comprises multiple computer modules disposed in a tank with cooling water circulating around the modules. It dissipates 6.3 MW at a water flow rate of 339 gallons per minute and has a power density of 1 kW/in3.