3D电源包装中的功率密度| Electronic Design

This article is part of the能源管理系列：探究电源密度

您将学到什么：

各种嵌入3D包装以提高功率密度的技术。
Different methods for cooling chips using 3D packaging.

用于3D包装的新技术和新兴技术正在印刷电路板（PCB）级别部署。可以通过组件集成到使用堆叠技术，集成，转换器等的芯片尺度软件包中来简化功率密度目标。高级冷却方法将有助于使3D包装成为可行的选择。

最新的技术创新和冷却方法将提高新设计的功率密度，并在较旧的设计中升级它。在本文中，这些创新和方法将大大提高3D功率包装中的功率密度。

Embedding and Integrating

面向/面朝下

Present-day technology enables embedding of such things as active and/or passive components, magnetics, and integrated filters into the circuit board.

Texas Instruments' MicroSIP was the first commercial dc-dc converter produced with theHERMES “face down approach.” The HERMES project aims at embedding active dies, face up or face down (flip chip), and (thin) passive components inside the dielectric layers of a PCB.

Embedding magnetics

Plated through hole (PTH) and blind via (BV) are two technologies that make it possible to嵌入（图1）。

Reliability of 3D Integrated Power Packaging

电力电子设计的功率密度不断提高将需要更好的冷却技术，例如集成冷却。控制功率组件的温度对于设备的可靠性和性能至关重要。但是，电力电子系统的创新热管理是电力致密化的关键瓶颈。

Wirebond/Solder Die Attach vs. Sintered Interconnects

For optimum power-density reliability, traditional wirebond techniques need to move toward sintered interconnects, which would eliminate wirebond failures.

Silver sintered power devices are an alternative interconnect technology to standard solders. The technology is different from other interconnect technologies due to improved thermal and mechanical properties. A high fatigue life is achieved in testing when compared to standard solder die attach and Al wire top contacts.

嵌入式组件

电容器

There are two methods of embedding capacitors into 3D structures:

嵌入式电容器膜
Embedded capacitor devices

Inductors

有两种将电感器嵌入3D结构的方法：

平面磁学
Deposited inductors

Cooling Methods in 3D Power Packaging

嵌入式歧管微通道冷却器

These types of coolers can be embedded directly into the substrate or chip and will provide localized heat removal at high volumetric rates from the backside of active integrated circuits and power electronic devices(Fig. 2)。它们可以以多种形式使用；例如，单相，硅与陶瓷底物和不同合金，过滤尺寸，工作流体，流体速度和温度。

Force-fed two-phase manifold cooler

A series of parallel microchannels can have perpendicularly oriented manifold to distribute flow(Fig. 3)。微轴表面是在单晶硅（SIC）中制造的。

彼此的充分热隔离电源

3D集成电源将使用新的包装技术。这些冷却方法的可靠性仍在理解和建模。

Fluid immersion cooling

Immersion cooling has risen as a solution to overcome barriers, such as single-phase cooling, by a method of boiling a cooling fluid directly from the electronic components. This will help remove the need for most thermal interface materials and packaging constraints found in many other approaches.

State-of-the-art immersion-cooling systems employ dielectric heat-transfer liquids due to electrical considerations. This presents fundamental disadvantages related to the relatively low boiling point, low critical heat flux (< 20 W/cm²), and relatively poor thermophysical properties (e.g., thermal conductivity, latent heat, surface tension) when compared to higher performance fluids such as water. However, compromises need to be considered since water can damage electronics systems. Check out “The Best Heat Transfer Fluids for Liquid Cooling (boydcorp.com)” for viable heat-transfer fluid options.

高热撞击的热传热

Improving the power density of advanced electronics, and in particular gallium-nitride (GaN) high electron mobility transistors (HEMTs) in RF power amplifiers, represents a big challenge in thermal management. High-heat-transfer capability of microjet impingement can be employed to bring cooling directly to the backside of the power electronic device(Fig. 4)。

High-power-density electronics device cooling loop using a liquid-metal coolant

This method employs the use of liquid gallium alloys, which have a thermal conductivity (approx. 28W/m/K) that’s 40 times greater than the thermal conductivity of water.

概括

This article has suggested some very powerful methods that designers can employ to increase power density in 3D packaging. For instance, embedding and integrating was mentioned as a good way to improve power density. Various cooling methods also were discussed as ways to boost power density. Which method is best suited for your 3D-packaging design?

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