CN116669399A - Novel mode for self-adaptive cooling of microelectronic device hot spot - Google Patents

Abstract

The invention discloses a novel method for self-adaptive cooling of hot spots of microelectronic equipment, and relates to the technical field of thermal management of microelectronic equipment. Ionized water is the continuous phase, and the low-boiling organic fluoride is the dispersed phase) as the heat-exchange working medium; when the phase-change emulsion flows through the background area of the microelectronic device, the high heat-carrying capacity of water is used for heat exchange, and when it flows through the hot spot The latent heat of vaporization of organic fluorides and the disturbance of boiling bubble droplets are used to synergistically enhance heat transfer in the region; the phase change emulsion can maintain a stable bubbly flow after boiling. The invention can realize self-adaptive cooling of hot spots of microelectronic equipment whose junction temperature is usually lower than 85°C, and uses boiling heat exchange technology to maintain the temperature of microelectronic equipment at a lower level at normal pressure, realizing the dynamic change process of hot spots of microelectronic equipment The combination of high-efficiency heat dissipation and safe and stable operation.

Description

A Novel Approach to Adaptive Cooling of Hotspots in Microelectronic Devices

technical field

The invention relates to the technical field of thermal management of microelectronic equipment, in particular to a novel method for self-adaptive cooling of hot spots of microelectronic equipment.

Background technique

In recent years, with the continuous development of miniaturization and integration of electronic equipment, the heat dissipation problem of microelectronic equipment has become more and more prominent, and the heat flux density in the hot spot area is more than 6 times that of the background area. The overheating of the hot spot will lead to the decline of the working performance of the microelectronic equipment. Secondly, the working temperature of the microelectronic equipment should be kept below 85°C. If the temperature of the local area is too high, the failure rate of the microelectronic equipment will continue to rise. In order to ensure the efficient and stable operation of microelectronic equipment in electronic equipment, various cooling methods for microelectronic equipment such as air cooling, water cooling, and semiconductor refrigeration have been developed, but it is difficult to achieve local efficient cooling for hot spots of microelectronic equipment.

Because water cooling has the advantages of low cost and high heat exchange efficiency, it is currently the main cooling method for microelectronic devices on the market, and its cooling medium is mostly deionized water. However, under normal pressure, the working medium water mainly takes away the heat on the surface of the microelectronic device in the form of single-phase laminar flow, and the continuous development of the boundary layer limits its heat transfer effect, although the overall microelectronic device can be strengthened by increasing the fluid flow rate. However, it is difficult to efficiently cool the hot spots of microelectronic devices due to its poor heat transfer performance. In addition, enhanced heat transfer methods such as introducing secondary runners or densely arranging micro-ribs in the hot spot area of microelectronic equipment are only suitable for predictable cooling of the hot spot area, and will greatly increase the system size while being unable to cope with complex hot spot position changes. voltage drop and device processing difficulty. In addition, using the deformation response characteristics of temperature-sensitive materials at different temperatures to adjust the heat transfer capacity between the working fluid and the wall or increasing the local flow rate of the working fluid to achieve adaptive cooling of any local random hot spot, such as shape memory alloy The self-adaptive deformation of the heat exchange structure at any local random hot spot can be realized, and the temperature-sensitive hydrogel shrinks when the temperature changes to adaptively regulate the flow rate of the heat exchange working medium. However, shape memory alloys have a memory fatigue life, and temperature-sensitive hydrogels easily cause channel pressure fluctuations in the process of releasing and absorbing water, which leads to the failure of existing cooling methods for hot spots in microelectronic devices to take into account dynamic changes in hot spots and safe and stable operation. .

Contents of the invention

The purpose of the invention is to provide a new method of self-adaptive cooling for hot spots of microelectronic equipment, to solve the problems existing in the above-mentioned prior art, and to achieve efficient heat dissipation and Taking into account the safety and stability of the operation.

To achieve the above object, the present invention provides the following scheme:

The invention provides a vapor-liquid phase-change nanoemulsion (deionized water is the continuous phase, and low-boiling organic fluoride is the dispersed phase) with a dispersed phase having amphiphobic properties as a heat-exchanging working medium for adaptive cooling of hot spots of microelectronic devices , to replace the traditional single-phase working medium.

Preferably, the organic fluorine compounds are all perfluoropolyethers, hydrofluoroethers, hydrofluoroolefins, etc. and mixtures thereof with a boiling temperature range of 20-85°C.

Preferably, the vapor-liquid phase change nanoemulsion with a dispersed phase volume fraction of less than 5% and a droplet diameter of 20-1000 nm is prepared by ultrasonic emulsification.

Preferably, the dispersed phase droplets in the vapor-liquid phase change nanoemulsion form a competitive wetting relationship with water on the surface of the heat exchange channel.

Preferably, the vapor-liquid phase change nanoemulsion can be used for self-adaptive cooling of hot spots of microelectronic devices whose junction temperature is lower than 85°C.

Preferably, the high sensible heat of water is used to cool the background region of the microelectronic device as it flows in the heat exchange channel.

Preferably, when the vapor-liquid phase change nanoemulsion flows through the background area of the microelectronic device in the heat exchange channel, the high sensible heat of water is used to cool the area.

Preferably, when the vapor-liquid phase change nanoemulsion flows through the hot spot area of the microelectronic device, the latent heat of vaporization of the low-boiling organic fluoride and the disturbance of boiling bubble droplets are used to enhance heat exchange.

Preferably, when the vapor-liquid phase change nanoemulsion flows out of the hot spot area and flows through the relatively low temperature background area again, the heat of the hot spot area is transferred to the water during the condensation process of the organic fluoride bubble droplets, to be boiled again, so that This enables efficient adaptive cooling for stochastic hotspot regions of microelectronic devices.

Preferably, the organic fluoride bubbles are not easy to coalesce, and can maintain a stable bubble flow in the heat exchange channel.

Preferably, the wall surface of the heat exchange channel is made of copper with excellent thermal conductivity, and is treated with hydrophilic or superhydrophilic treatment.

Preferably, the width of the heat exchange channel can be reduced to a sub-millimeter level.

The invention discloses the following technical effects:

The invention utilizes the high heat-carrying capacity of water, the latent heat of vaporization of the dispersed phase, and the disturbance of boiling bubble droplets when the vapor-liquid phase change nano-emulsion flows through the hot spot area of the microelectronic device to carry out synergistically enhanced heat transfer, so as to achieve a temperature lower than that of the microelectronic device. The flow boiling heat transfer technology is used at the junction temperature of the electronic equipment (85°C), and a stable bubbly flow is maintained in the channel, which can efficiently and adaptively cool the hot spots of the microelectronic equipment while taking into account the safe and stable operation of the system.

Description of drawings

In order to illustrate the technical solution in the present invention more clearly, the accompanying drawings that need to be used in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only technical explanations of the present invention. As far as the skilled person is concerned, other drawings can also be obtained based on these drawings on the premise of not paying creative work.

Figure 1 is a schematic diagram of a hot spot adaptive cooling method of a microelectronic device;

Among them, organic fluoride droplet 1 ; organic fluoride bubble drop 2 ; hotspot area 3 ; background area 4 ; and microelectronic device 5 .

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The present invention provides a vapor-liquid phase change nanoemulsion with amphiphobic dispersed phase as a heat-exchanging working fluid for adaptive cooling of hot spots of microelectronic equipment, replacing traditional single-phase working fluids, and taking into account the high-efficiency adaptive cooling of hot spots and the The system runs safely and stably.

In order to make the above objects, features and effects of the present invention more obvious and comprehensible, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As a preferred specific implementation, the phase transition temperature range of the low-boiling organic fluorides provided in this example is 20-85°C, which is higher than the initial ambient temperature and lower than that of microelectronics in specific use environments. The maximum junction temperature of the device.

As a preferred specific implementation, in this example, ultrasonic emulsification is used to prepare vapor-liquid phase change nanoemulsions, and low-boiling organic fluorides with a volume fraction of less than 3% are added to deionized water to make low-boiling organic fluorides with amphiphobic properties Organic fluoride and water are ultrasonically emulsified into vapor-liquid phase change nanoemulsion at room temperature.

As a preferred specific implementation, the diameter of the dispersed phase droplet is changed by changing the ultrasonic frequency, power and time, and the volume fraction of the dispersed phase is changed to adapt to the actual thermal design power consumption and hot spot heating law of the microelectronic device. Preferably, a 3% volume fraction HFE-7100/water nanoemulsion is prepared by using an ultrasonic disperser with a frequency of 28 kHz and ultrasonicating at a power of 60 W for 10 min.

As a preferred embodiment, the wall surface of the heat exchange channel should be made of red copper with excellent thermal conductivity.

As a preferred specific implementation, the heat exchange channel is processed to a sub-millimeter level.

As a preferred embodiment, a mixed solution of sodium hydroxide and ammonium persulfate is used to oxidize the polished and cleaned copper channel wall, and channels with different hydrophilicities are prepared by controlling the oxidation time to meet the pumping power requirements.

Figure 1 is a front cross-sectional view of the flow and boiling process of a vapor-liquid phase change nanoemulsion with dispersed phase having amphiphobic properties in the channel. The position and number of internal hot spots are not limited to those shown in Figure 1, according to the actual work of microelectronic equipment Status changes in real time.

The working principle of adaptive cooling of hot spots of microelectronic devices by vapor-liquid phase change nanoemulsion is as follows:

The vapor-liquid phase change nanoemulsion flows in from the entrance of the channel. When it flows through the background area 4 of the microelectronic device 5 for the first time, the wall temperature of the background area 4 is lower than the boiling point of the organic fluoride droplet 1. At this time, the high temperature of water is used to Sensible heat cools this area; when the emulsion flows through the hot spot area 3 of the microelectronic device, the temperature of the emulsion in the thermal boundary layer rises to the boiling point of the organic fluoride, and at this time, the low-boiling organic fluoride droplet 1 occurs in the continuous phase water Boiling produces organic fluoride bubbles 2; when the emulsion flows out of the hot spot 3 and flows through the relatively low temperature background area 4 again, the process of organic fluoride bubbles 2 condensing into organic fluoride droplets 1 will dissipate the hot spot 3 Heat is transferred to the water in the background area 4 to be reboiled, thereby enabling adaptive cooling of the random hotspot area 3 of the microelectronic device.

Compared with the prior art, the innovative part of the application is as follows:

Most of the existing cooling systems for microelectronic equipment use deionized water as the boiling working medium. Under normal pressure, flow boiling heat transfer can only be achieved when the wall temperature exceeds 100°C. At this temperature, the failure rate of microelectronic equipment is extremely high. Secondly, although most organic fluorides (boiling point 20-85°C) with high saturated vapor pressure and low viscosity can boil at 85°C, their thermal conductivity and specific heat capacity are small. The heat transfer capacity of single-phase flow is significantly lower than that of water under the same working conditions. In the process of flow boiling, there are inevitably problems such as bubble layer accumulation, working medium drying up, and flow instability during the boiling process of a single homogeneous working medium. Neither of the above two common heat transfer fluids can perform adaptive cooling on random hot spots of microelectronic devices. The vapor-liquid phase change nanoemulsion with dispersed phase has amphiphobic properties is used as the heat exchange medium. When the emulsion flows through the background area, it relies on the single-phase flow of water to exchange heat, and when it flows through the hot spot area, it takes advantage of the high sensible heat of water and The latent heat of vaporization of low-boiling organic fluorides synergistically enhances heat transfer, realizing efficient adaptive cooling of random hot spots in microelectronic devices, while taking into account the safe and stable operation of the system.

It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. . Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the invention, and any reference sign in a claim shall not be construed as limiting the claim concerned.

In the present invention, specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only used to help understand the method and core idea of the present invention; meanwhile, for those of ordinary skill in the art, according to the present invention The idea of the invention will have changes in the specific implementation and scope of application. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims (6)

1. A novel mode for self-adaptive cooling of a microelectronic device hot spot is characterized in that: the dispersed phase has the vapor-liquid phase change nanoemulsion with the double-hydrophobic (hydrophobic and oleophobic) characteristic (deionized water is a continuous phase, low-boiling organic fluoride is a dispersed phase), high sensible heat advantage heat exchange of water is utilized when the water flows through a background area of the microelectronic device in a heat exchange channel, vaporization latent heat of the low-boiling organic fluoride and disturbance of boiling bubble droplets are utilized to cooperatively strengthen heat exchange when the water flows through a hot spot area, and heat of the hot spot area is transferred into the water of the background area by the heat bubble droplets when the water flows through the background area again, so that efficient self-adaptive cooling for the random hot spot area of the microelectronic device is realized.

2. A novel approach to microelectronic device hotspot adaptive cooling as claimed in claim 1, wherein: the organic fluoride comprises perfluoro polyether, hydrofluoroether, hydrofluoroolefin and the like and the mixture thereof, and the boiling point temperature range is 20-85 ℃.

3. A novel approach to microelectronic device hotspot adaptive cooling as claimed in claim 1, wherein: the diameter of the dispersed phase liquid drop in the vapor-liquid phase change nano emulsion with the disperse phase having amphiphobic characteristic is between 20 and 1000 nm.

4. A novel approach to microelectronic device hotspot adaptive cooling as claimed in claim 1, wherein: after the surface of the heat exchange channel is subjected to hydrophilic treatment, dispersed phase liquid drops in the nano emulsion and deionized water form a competitive wetting relationship on the surface.

5. A novel approach to microelectronic device hotspot adaptive cooling as claimed in claim 1, wherein: the novel microelectronic device hot spot self-adaptive cooling-oriented mode is used for temperature control and heat dissipation of microelectronic devices with junction temperatures not higher than 85 ℃.

6. A novel approach to microelectronic device hotspot adaptive cooling as claimed in claim 1, wherein: the volume fraction of the organic fluoride in the vapor-liquid phase-change nano emulsion is not higher than 5%.