CN111599776A - A multi-layer composite nanoporous evaporator - Google Patents

Abstract

A multi-layer composite nano porous evaporator belongs to the technical field of microelectronic device cooling. Generally consisting of an upper silicon structure, a middle nanoporous structure and a lower silicon structure. The upper silicon structure includes seven manifold channels, an inlet reservoir, an outlet reservoir, and a plurality of vapor channels. The middle layer nano porous structure is obtained by etching processing on the upper layer silicon surface, and the nano hole arrays are uniformly distributed on the film. The lower silicon structure comprises a liquid inlet, a liquid outlet, parallel ribs and micro-channels among the ribs, and is connected with the upper layer by a bonding technology. The device utilizes the thin film evaporation heat dissipation of liquid in the nanometer holes, has the characteristics of stable operation, uniform temperature distribution, high strength of the nanometer film, less required working medium, low pumping power consumption and the like, and solves the problems of high heat flow density and multi-heat-area distribution of microelectronic devices.

Description

A multi-layer composite nanoporous evaporator

technical field

The invention relates to a novel multi-layer composite nano-porous evaporator, which belongs to the technical field of cooling of microelectronic devices.

technical background

In recent years, with the rapid development of electronic chip manufacturing, military industry, new energy application technology and aerospace fields, new requirements for "miniaturization", "high integration" and "high power" have been put forward for electronic devices in engineering applications. Microelectronic devices such as Gallium Nitride (GaN) High Electron Mobility Transistors (HEMTs) are widely used in various fields. However, the heat dissipation problem on the local hot spot greatly limits the output power of microelectronic devices. It is found that the heat flux density generated is as high as 5kW/cm ² in some sub-millimeter regions of GaN-based HEMT devices. Therefore, how to effectively dissipate heat to improve the power of microelectronic devices and prolong their working life has become an urgent problem to be solved. At present, the traditional heat dissipation solutions for high heat flux density electronic devices at home and abroad mainly include: high thermal conductivity solid soaking materials (copper, tungsten copper and diamond, etc.) or thermal interface materials (solder, thermal grease and epoxy resin, etc.) Combined with air cooling or liquid cooling cold plate to achieve the purpose of heat dissipation. However, due to the existence of contact thermal resistance, the traditional heat dissipation method cannot effectively reduce the junction temperature, which seriously threatens the safe and stable operation of the device. In order to solve this problem, the researchers proposed a new type of embedded cooling scheme for electronic devices. The heat is directly dissipated from the substrate of the electronic device, rather than at the packaging level of the electronic device. temperature. The insulating dielectric liquid is then used as a cooling medium to ensure that no magnetic field is generated in the working area of the device, thereby ensuring the operation performance of the electronic device.

In recent years, NEMS (Nano-Electromechanical System) technology has developed rapidly, and the heat transfer problem in the nanoscale has become a frontier science in the field of heat transfer. A large number of studies have proved that the phase transition on the nanoporous membrane can consume a lot of heat, so the use of nanoporous membranes for embedded heat dissipation of high heat flux microelectronic devices has been affirmed by many researchers. The in-depth research results propose the following criteria for high-performance nanoporous evaporation devices: (1) low thermal resistance for heat transfer from the substrate to the liquid-air interface; (2) capable of generating large capillary forces to transport the required evaporation Working fluid; (3) Effective liquid supply structure, which can minimize pressure drop; (4) Efficient steam transport channel. However, at the design level, how to achieve the above standards has troubled people. At present, the main problems faced by nano-porous heat dissipation equipment at home and abroad are: poor mechanical strength of nano-membranes; using flow channels for liquid supply can easily lead to clogging of nano-pores; no independent steam The channel makes the gas-liquid separation ineffective, etc.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a novel multi-layer composite nanoporous evaporator in view of the above-mentioned deficiencies of the prior art.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a multi-layer composite nanoporous evaporator, which is generally composed of three-layer structures, which are an upper-layer silicon structure (1) and a middle-layer nanoporous membrane structure (2). ) and the lower layer silicon structure (3); wherein the middle layer nanoporous membrane structure (2) is directly processed on the lower surface of the upper layer silicon structure (1), and the lower layer silicon structure (3) is bonded to the middle layer nanoporous membrane structure (2) by bonding connect.

The upper layer silicon structure includes N steam channels (1.1), N+1 manifold channels (1.2), an inlet liquid storage pool (1.3), and an outlet liquid storage pool (1.4); the N steam channels (1.1) are multi-channel parallel An independent rectangular channel, and both ends of the rectangular channel are closed in the length direction; N+1 manifold channels (1.2) are formed between the N steam channels (1.1) and the two sides of the outermost two steam channels (1.1); The two ends in the length direction of the N steam passages (1.1) correspond to the inlet liquid storage tank (1.3) and the outlet liquid storage tank (1.4); the manifold channel (1.2) is respectively connected with the inlet liquid storage tank (1.3) and the outlet liquid storage tank The liquid pool (1.4) is connected so that the liquid working medium can flow from the inlet liquid storage tank (1.3) to the outlet liquid storage tank (1.4) through the manifold channel (1.2); a plurality of steam channels (1.1) are distributed in parallel to the N+ Between 1 manifold channel (1.2), the steam generated by evaporation can be transported efficiently; only N steam channels (1.1) are exposed on the upper surface of the upper silicon structure, N+1 manifold channels (1.2), inlet The liquid storage tank (1.3) and the outlet liquid storage tank (1.4) are closed;

The middle-layer nanoporous membrane structure (2) is obtained by etching the lower surface of the upper silicon layer (1), and an independent nanoporous membrane (2.1) with nanopores (2.2) is provided at the lower port of each vapor channel (1.1). ; The position of the N-block nanoporous membrane (2.1) corresponds to the N vapor channels (1.1) in the upper silicon structure (1), so that the formed nanopore (2.2) array is uniformly arranged on the N-block nanoporous membrane (2.1) The pore size of a single nanopore is about 200 nm.

Preferably, each nanoporous membrane (2.1) has the same size as the lower port of the corresponding steam channel (1.1); the corresponding inlet liquid storage pool (1.3), outlet liquid storage pool (1.4), The positions of the manifold channels (1.2) are all vacant without corresponding membranes;

The lower silicon structure (3) comprises ribs (3.2) arranged in parallel, microchannels (3.1) between the ribs, a liquid inlet (3.3) and a liquid outlet (3.4); the liquid inlet (3.3) and the liquid outlet (3.4) are symmetrical structures , corresponding to the inlet liquid storage tank (1.3) and the outlet liquid storage tank (1.4) in the upper layer silicon structure (1), so that the liquid working medium can enter and exit the inlet liquid storage tank from the liquid inlet (3.3) and the liquid outlet (3.4). (1.3), outlet reservoir (1.4); ribs (3.2) and microchannels (3.1) between ribs are provided on the upper surface of the lower silicon structure (3); parallel ribs (3.2) are formed between parallel ribs (3.2). Arranged microchannels (3.1), the tops of ribs (3.2) are in contact with the nanoporous membrane (2.1) in the middle layer, providing support for the nanoporous membrane (2.1), while the liquid in the microchannels (3.1) utilizes the nanopores (2.2 The strong capillary force in ) supplies the liquid for the evaporation process.

The length direction of the ribs (3.2) is perpendicular to the length direction of the nanoporous membrane (2.1).

Each nanoporous membrane (2.1) is provided with two rows of nanopores (2.2).

The cross-sections of the inlet liquid storage tank (1.3) and the outlet liquid storage tank (1.4) are both trapezoidal structure cavities, and the cross-section is parallel to the middle-layer nanoporous membrane structure (2); the long bottom surface of the trapezoidal structure is parallel to the corresponding steam channel (1.1) the end of the other short bottom face away from the end of the steam channel (1.1).

N is a number from 4-10.

The ribs (3.2) on the lower surface of the underlying silicon structure (3) and the microchannels (3.1) between the ribs correspond to the hot zone (3.5). The microchannels (3.1) between the ribs do not penetrate through the underlying silicon structure (3). the lower surface, so that the hot zone corresponding to the lower surface of the lower silicon structure (3) is a planar structure.

The beneficial effects of the present invention are:

In the new multi-layer composite nanoporous evaporator, the heat source is located at the bottom of the evaporator so that the heat can be dissipated directly on the substrate of the electronic device, which belongs to the embedded cooling scheme. Compared with the traditional heat dissipation method of external heat sink, the contact thermal resistance is greatly reduced due to the reduction of the use of interface materials, which in turn greatly reduces the junction temperature of the device and ensures the safe and stable operation of the electronic device. The design of a plurality of nanoporous membranes (2.1) staggered and arranged in parallel with the manifolds (1.2) ensures the mechanical strength of a single nanoporous membrane (2.1) while maximizing the evaporation area. The separate design of the manifold (1.2) as the flow channel and the microchannel (3.1) as the liquid supply channel not only ensures the fluidity of the liquid, but also avoids problems such as clogging of the nanopores (2.2) caused by the liquid flow. The microchannels (3.1) in the structure both provide mechanical support for the nanoporous membrane (2.1) to increase the strength of the membrane again, and its ribs (3.2) also conduct heat to the phase transition interface. At the same time, the capillary suction effect of the nanopore (2.2) is used to achieve sufficient liquid supply, which greatly reduces the pump power consumption in the traditional liquid cooling scheme, and limits the evaporation process to the thin film evaporation area. 1.1) Effectively complete gas-liquid separation. The layered structure of the flow channels within the device also helps reduce flow resistance. In this structure, the liquid phase change method combines the advantages of pool boiling and flow boiling, which can meet the heat dissipation and cooling requirements of high heat flux density, and avoid the appearance of instability, which is an ideal cooling method.

Description of drawings

FIG. 1 is a schematic diagram of the overall structure of the present invention.

FIG. 2 is a schematic diagram of a frontal explosion of the overall structure of the present invention.

FIG. 3 is a schematic diagram of the backside explosion of the overall structure of the present invention.

FIG. 4 is a schematic front view of the upper layer silicon structure of the present invention.

FIG. 5 is a schematic diagram of the backside of the upper layer silicon structure of the present invention.

FIG. 6 is a schematic diagram of the middle-layer nanoporous structure of the present invention.

FIG. 7 is a schematic front view of the underlying silicon structure of the present invention.

FIG. 8 is a schematic diagram of the backside of the underlying silicon structure of the present invention.

FIG. 9 is a work flow demonstration diagram of the present invention.

In the figure, 1. upper layer silicon structure; 1.1, steam channel; 1.2, manifold channel; 1.3, inlet liquid storage tank; 1.4, outlet liquid storage tank; 2, middle layer nanoporous structure; 2.1, nanoporous membrane; 2.2, nanometer hole; 3. lower silicon structure; 3.1, microchannel; 3.2, rib; 3.3, liquid inlet; 3.4, liquid outlet; 3.5, hot zone.

Detailed ways

The present invention will be described in further detail below with reference to the accompanying drawings, but the present invention is not limited to the following examples.

Example 1

As shown in Figures 1, 2, 3, 4, 5, 6, 7, and 8, a novel multi-layer composite nanoporous evaporator includes an upper layer silicon structure (1), a middle layer nanoporous membrane structure (2) and a lower layer Silicon structure (3). The upper silicon structure is a flow module consisting of six vapor channels (1.1), seven manifold channels (1.2), an inlet liquid reservoir (1.3) and an outlet liquid reservoir (1.4). The middle-layer nanoporous structure is an evaporation module, which is composed of six nanoporous membranes (2.1) with uniformly arranged arrays of nanopores (2.2). The lower silicon structure is a liquid supply module, which is composed of a liquid inlet (3.3), a liquid outlet (3.4), and a staggered arrangement of ribs (3.2) and microchannels (3.1).

A plurality of steam passages (1.1) are staggered with the manifold passages (1.2), and both sides of the manifold passages (1.2) are communicated with the inlet liquid storage tank and the outlet liquid storage tank in a symmetrical structure; the nanoporous structure (2) in the middle layer is for evaporation Module, the array of nanopores (2.2) is evenly distributed on a plurality of nanoporous membranes (2.1), and the position of each membrane corresponds to each vapor channel (1.1) of the upper layer; the lower silicon structure (3) is the liquid supply Module, the liquid inlet (3.3) is communicated with the upper inlet liquid storage tank (1.3), the liquid outlet (3.4) is connected with the upper outlet liquid storage tank (1.4), and a volume is formed between the parallel ribs (3.2) in the central area The same microchannel (3.1). The middle-layer nanoporous membrane structure (2) is directly etched on the surface of the upper-layer silicon structure (1), and then connected to the lower-layer silicon structure (3) by bonding.

It is composed of three layers with different functions, that is, an upper layer silicon structure (1), a middle layer nanoporous membrane structure (2) and a lower layer silicon structure (3), and the outer shape and size of the contact surface between each layer are the same.

In the central area, six steam channels (1.1) and seven manifolds (1.2) are alternately arranged in parallel. The steam channels (1.1) pass through the upper silicon structure (1) and have a horizontal area equal to that of a single nanoporous membrane (2.1).

The nanopore (2.2) arrays are uniformly arranged on the six membranes, and the diameter of a single nanopore is about 200 nm.

The area of the entire microchannel area corresponds to and is equal to the area of the entire nanoporous membrane area of the middle layer and the area of the vapor channel and manifold area of the upper layer.

The positions of the six nanoporous membranes (2.1) correspond to the six vapor channels (1.1) respectively in the vertical direction, so that each nanoporous membrane (2.1) has an independent vapor channel (1.1).

The liquid inlet and outlet are located in the lower layer, and the inlet and outlet liquid storage tanks and manifold channels (1.2) are located in the upper layer, so that the fluid can complete the flow process from bottom to top and then outflow from bottom.

The manifold channel (1.2) and the microchannel (3.1) have different functions and exist independently of each other, realizing the separate design of the flow channel and the liquid supply channel.

From a top view, the manifold channels (1.2) and the microchannels (3.1) are arranged vertically rather than horizontally, which is beneficial to the uniform distribution of the liquid in the microchannels (3.1).

It is assumed that the novel multi-layer composite nanoporous evaporator is mounted on a microelectronic device such that the bottom of the evaporator is in contact with the hot zone (3.5). As shown in Fig. 9, the liquid working medium flows from the liquid inlet (1.3) into the inlet liquid storage tank (3.3) through the external liquid supply pipe, and a part of the liquid enters the microstructure of the lower silicon structure (3) when passing through the seven manifold channels (1.2). In the channel (3.1), another part of the liquid flows into the outlet reservoir (1.4) and flows out from the liquid outlet (3.4).

The nanoporous membrane (2.1) is located above the microchannel (3.1), and the strong capillary force in the nanopore (2.2) can stably supply the liquid working medium in the microchannel (3.1) to the nanopore (2.2), while the ribs ( 3.2) Conducting the heat generated by the hot zone (3.5) of the microelectronic device on the bottom surface to the six nanoporous membranes (2.1), so that the liquid can achieve stable thin film evaporation in the nanopores (2.2), and then pass through six independent vapor channels (1.1) Complete gas-liquid separation effectively.

Claims (9)

1. a multilayer composite nanoporous evaporator, is characterized in that, generally consists of three-layer structure, is respectively upper layer silicon structure (1), middle layer nanoporous membrane structure (2) and lower layer silicon structure (3); The middle-layer nanoporous membrane structure (2) is directly processed on the lower surface of the upper-layer silicon structure (1), and the lower-layer silicon structure (3) is connected to the middle-layer nanoporous membrane structure (2) by bonding; The layered silicon structure includes N steam channels (1.1), N+1 manifold channels (1.2), an inlet liquid storage pool (1.3), and an outlet liquid storage pool (1.4); the N steam channels (1.1) are multi-channel parallel An independent rectangular channel, and both ends of the rectangular channel are closed in the length direction; N+1 manifold channels (1.2) are formed between the N steam channels (1.1) and the two sides of the outermost two steam channels (1.1); The two ends in the length direction of the N steam passages (1.1) correspond to the inlet liquid storage tank (1.3) and the outlet liquid storage tank (1.4); the manifold channel (1.2) is respectively connected with the inlet liquid storage tank (1.3) and the outlet liquid storage tank The liquid pool (1.4) is connected so that the liquid working medium can flow from the inlet liquid storage tank (1.3) to the outlet liquid storage tank (1.4) through the manifold channel (1.2); a plurality of steam channels (1.1) are distributed in parallel to the N+ Between 1 manifold channel (1.2), the steam generated by evaporation can be transported efficiently; only N steam channels (1.1) are exposed on the upper surface of the upper silicon structure, N+1 manifold channels (1.2), inlet The liquid storage tank (1.3) and the outlet liquid storage tank (1.4) are closed; The middle-layer nanoporous membrane structure (2) is obtained by etching the lower surface of the upper silicon layer (1), and an independent nanoporous membrane (2.1) with nanopores (2.2) is provided at the lower port of each vapor channel (1.1). ; The position of the N-block nanoporous membrane (2.1) corresponds to the N vapor channels (1.1) in the upper silicon structure (1), so that the formed nanopore (2.2) array is uniformly arranged on the N-block nanoporous membrane (2.1) cloth; The lower silicon structure (3) comprises ribs (3.2) arranged in parallel, microchannels (3.1) between the ribs, a liquid inlet (3.3) and a liquid outlet (3.4); the liquid inlet (3.3) and the liquid outlet (3.4) are symmetrical structures , corresponding to the inlet liquid storage tank (1.3) and the outlet liquid storage tank (1.4) in the upper layer silicon structure (1), so that the liquid working medium can enter and exit the inlet liquid storage tank from the liquid inlet (3.3) and the liquid outlet (3.4). (1.3), outlet reservoir (1.4); ribs (3.2) and microchannels (3.1) between ribs are provided on the upper surface of the lower silicon structure (3); parallel ribs (3.2) are formed between parallel ribs (3.2). Arranged microchannels (3.1), the tops of ribs (3.2) are in contact with the nanoporous membrane (2.1) in the middle layer, providing support for the nanoporous membrane (2.1), while the liquid in the microchannels (3.1) utilizes the nanopores (2.2 The strong capillary force in ) supplies liquid for the evaporation process; N is a number from 4-10. 2. A kind of multi-layer composite nanoporous evaporator according to claim 1 is characterized in that, each nanoporous membrane (2.1) is consistent with the lower port size of the corresponding steam channel (1.1); in the middle nanoporous membrane The positions of the corresponding inlet liquid storage tank (1.3), outlet liquid storage tank (1.4), and manifold channel (1.2) in the structure (2) are all vacant without corresponding membranes. 3. A multi-layer composite nanoporous evaporator according to claim 1, characterized in that the length direction of the ribs (3.2) is perpendicular to the length direction of the nanoporous membrane (2.1). 4. A multi-layer composite nanoporous evaporator according to claim 1, characterized in that, each nanoporous membrane (2.1) is provided with two rows of nanopores (2.2). 5. A multi-layer composite nanoporous evaporator according to claim 1, characterized in that, the corresponding ribs (3.2) and the microchannels (3.1) between the ribs on the lower surface of the lower silicon structure (3) Corresponding to the hot zone (3.5), the microchannels (3.1) between the ribs do not penetrate the lower surface of the lower silicon structure (3), so that the hot zone corresponding to the lower surface of the lower silicon structure (3) is a planar structure. 6. The multi-layer composite nanoporous evaporator according to claim 1, wherein the cross-sections of the inlet liquid storage tank (1.3) and the outlet liquid storage tank (1.4) are trapezoidal structure cavities, and the The cross section is parallel to the middle-layer nanoporous membrane structure (2); the long bottom surface of the trapezoidal structure is parallel to the end of the steam channel (1.1), and the other short bottom surface is away from the end of the steam channel (1.1). 7 . The multi-layer composite nanoporous evaporator according to claim 1 , wherein the plurality of vapor channels ( 1.1 ) are six vapor channels ( 1.1 ), and the diameter of a single nanopore is 200 nm. 8 . 8. A multi-layer composite nanoporous evaporator according to claim 1, characterized in that, the upper layer silicon structure (1), the middle layer nanoporous membrane structure (2) and the lower layer silicon structure (3), each layer of The outer shape and size of the indirect contact surface are the same; The steam channel (1.1) and the manifold (1.2) are alternately arranged in parallel in the central area, the steam channel (1.1) penetrates the upper silicon structure (1) and the horizontal area is equal to that of a single nanoporous membrane (2.1); The area of the entire microchannel area corresponds to and is equal to the area of the entire nanoporous membrane area of the middle layer and the area of the vapor channel and manifold area of the upper layer; The positions of the nanoporous membranes (2.1) are respectively corresponding to the steam channels (1.1) in the vertical direction, so that each nanoporous membrane (2.1) has an independent steam channel (1.1); From a top view, the manifold channels (1.2) and the microchannels (3.1) are arranged vertically rather than horizontally, which is beneficial to the uniform distribution of the liquid in the microchannels (3.1). 9. A multi-layer composite nanoporous evaporator according to claim 1, characterized in that, during application: the bottom of the evaporator is made to contact the hot zone (3.5), and the liquid working medium passes through the external liquid supply pipe from the liquid inlet (1.3) flows into the inlet liquid storage tank (3.3), a part of the liquid enters the microchannel (3.1) of the lower silicon structure (3) when passing through the manifold channel (1.2), and another part of the liquid flows into the outlet liquid storage tank (1.4) and from the liquid outlet (3.4); The nanoporous membrane (2.1) is located above the microchannel (3.1), and the strong capillary force in the nanopore (2.2) can stably supply the liquid working medium in the microchannel (3.1) to the nanopore (2.2), while the ribs ( 3.2) Conduct the heat generated by the hot zone (3.5) of the microelectronic device on the bottom surface to the nanoporous membrane (2.1), so that the liquid can achieve stable thin film evaporation in the nanopore (2.2), and then effectively pass through the independent vapor channel (1.1) complete gas-liquid separation.

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