AlSiC Stiffener and Sealing Layout for Lidless Liquid-Cooled Modules

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Solution Overview

Problem

High power density and thermal challenges in data centers due to temperature differentials in electronic component packages, leading to warpage issues, which are not effectively addressed by existing technologies.

Innovation Solution

A weight-optimized stiffener made of silicon carbide particles in an aluminum matrix, with specific geometric features for reduced thermal mass and weight optimization, providing warpage control for lidless packages while enabling direct liquid cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a traditional stiffener is used in electronic component packages, then structural support and warpage control are provided, but the thermal mass is high and weight concentrations cause thermal management challenges

Engineering Contradiction:
Improvewarpage controlVSAvoidthermal mass
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The stiffener is constructed from aluminum alloy, a composite material that provides high strength-to-weight ratio. This allows the stiffener to maintain structural support and warpage control capabilities while significantly reducing thermal mass compared to traditional materials, thereby resolving the contradiction between strength and weight

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the stiffener's geometric parameters including thickness, shape, and positioning to optimize the balance between structural support and thermal mass. By adjusting these parameters, the stiffener maintains adequate warpage control while minimizing weight concentrations that would hinder thermal management

Inventive Principle:
Principle #35Parameter changes

2Productivity

If high power density components are used to increase compute performance, then energy efficiency and compute density improve, but thermal challenges and temperature differentials increase causing warpage

Engineering Contradiction:
Improvecompute densityVSAvoidtemperature differential
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The stiffener incorporates segmented or distributed support structures rather than a single monolithic component. This segmentation allows for better heat distribution and reduced localized thermal stress, addressing the warpage issue caused by temperature differentials while maintaining high compute density

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stiffener design applies different properties or configurations in different regions to address local thermal conditions. Areas with higher heat generation receive enhanced support or thermal management features, while cooler regions use lighter structures, thereby managing temperature differentials effectively

Inventive Principle:
Principle #3Local quality

3Temperature

If lidless package design is used for direct liquid cooling, then thermal management improves, but warpage control becomes more difficult

Engineering Contradiction:
Improvethermal managementVSAvoidwarpage control
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The stiffener acts as an intermediary component between the lidless package structure and the liquid cooling system. It provides the necessary structural support and warpage control that would otherwise be provided by a lid, while allowing direct liquid cooling to function effectively

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The stiffener performs multiple functions simultaneously: it provides structural support, controls warpage, and facilitates thermal management in the lidless package design. This multi-functionality resolves the contradiction by making the single component adequate for both mechanical and thermal requirements

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution effectively controls warpage and enhances thermal management in high-density server environments, improving compute performance and energy efficiency while reducing material costs and thermal stresses.

Implementation Method 1

Due to differences in the thermal coefficient of expansion (CTE) of the various package components, the electronic component package may warp as the temperature of the electronic component package changes

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

Because liquid is many times better at storing and transferring heat than air, liquid cooling solutions can provide immediate and measurable benefits to compute efficiency, density and performance

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3913663B1Weight optimized stiffener and sealing structure for direct liquid cooled modules
Publication Date: 2024.07.03 GOOGLE LLC
  • EP3913663B1 patent drawingFigure 1
  • EP3913663B1 patent drawingFigure 2A~2D
  • EP3913663B1 patent drawingFigure 3A~3B

AI summary

A weight optimized stiffener for use in a semiconductor device is disclosed herein. In one example, the stiffener is made of AlSiC for its weight and thermal properties. An O-ring provides sealing between a top surface of the stiffener and a component of the semiconductor device and adhesive provides sealing between a bottom surface of the stiffener and another component of the semiconductor device. The stiffener provides warpage control for a lidless package while enabling direct liquid cooling of a chip or substrate.