CN115064502A

CN115064502A - Heat-pipe-control micro-channel LTCC-M packaging substrate and manufacturing method thereof

Info

Publication number: CN115064502A
Application number: CN202210547703.0A
Authority: CN
Inventors: 海洋; 鲁聪
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2022-05-18
Filing date: 2022-05-18
Publication date: 2022-09-16

Abstract

The invention discloses a heat-pipe-control micro-channel LTCC-M packaging substrate which is uniform in heat dissipation and high in heat convection efficiency, can effectively improve the heat dissipation capacity and reduce the heat resistance of a heat dissipation channel, and is realized by the following technical scheme: the chip heat transfer channel with the embedded chip is embedded in an LTCC substrate of a metal layer below a heat source, a plurality of layers of micro-channel units which are combined into a whole by a metal layer heat exchange channel and are horizontally convected and heat exchanged and are linearly and parallelly arranged in a blind cavity of a metal structure are arranged in the direction of the heat channel below the chip heat transfer channel, and the array heat conduction metal micro-columns which are fixedly connected with a gradient functional FGM material interface isolation layer and are embedded in a cavity of an LTCC ceramic layer are fixedly connected, so that a heat management unit which is formed by the metal layer heat exchange channel, the array metal micro-columns, the multi-layers of micro-channel units, the LTCC ceramic layer interface, the liquid cooling channel and the heat transfer channel heat interface for convecting and exchanging heat is formed by the gradient heat exchange functional interface, the array metal micro-columns, the multi-layers of micro-channel units, the LTCC ceramic layer and the liquid cooling channel and the heat transfer channel heat interface.

Description

Heat-pipe-control micro-channel LTCC-M packaging substrate and manufacturing method thereof

Technical Field

The invention relates to the field of microwave and millimeter wave application, and is widely applied to a microsystem for realizing high-density integration in a system-in-package (SIP) of LTCC. In particular to a heat-pipe-control micro-channel LTCC-M packaging substrate and a manufacturing process method thereof.

Background

The low temperature co-fired ceramic (LTCC) has excellent performance, is an important component in modern microelectronic packaging, and has wide application in the fields of microwave and millimeter wave application. But also widely applied to high-speed and high-frequency systems. The LTCC multilayer substrate technology can be used for manufacturing circuit substrates with dozens of layers, passive elements can be embedded in the LTCC substrate, and partial passive elements can be integrated into the substrate, so that the miniaturization of a system is facilitated, and the assembly density of a circuit and the reliability of the system are improved. Because the LTCC substrate has the advantages of high number of wiring layers, small square resistance of wiring conductors, low dielectric constant, low sintering temperature and the like, a plurality of chips with different functions, different powers and different frequencies can be packaged together, the integration of passive elements can be realized, and a plurality of resistors, capacitors, inductors and the like are embedded in the substrate, so that a large amount of space is vacated on the surface of the substrate for assembling other components. The micro-system capable of realizing high-density integration in LTCC-based system-in-package (SIP) application becomes a feasible realization scheme of a ceramic monolithic integration system. LTCC is therefore used in a large number of electronic equipment. However, the poor thermal conductivity of LTCC results in that the heat generated by the operation of the LTCC substrate integrated power device cannot be dissipated quickly and timely, which becomes a weak point limiting the application of LTCC in high power microwave components and multifunctional microsystems. And with the rapid development of electronic equipment, the electronic equipment has the characteristics of miniaturization in size, complicated structure, high assembly density, high power and the like, and the heat flow density of the high-density three-dimensional integrated power module is increased sharply, so that a new and more severe heat control problem is brought.

The LTCC substrate can fully exert the performance advantages of large-scale integrated circuits and high-speed integrated circuits, so that the integration level of the hybrid integrated circuits is higher, and hybrid large-scale integrated circuits (HLSI) are realized. However, LTCC is a glass/ceramic product, the actual breaking strength is generally less than 200Mpa, the mechanical impact resistance is not very high, and the substrate is prone to crack or break under a slightly large impact, so that the circuit fails. The thermal conductivity of LTCC is usually 2 to 3 w/(m.k) because of its low thermal conductivity. When power components exist in the circuit, the heat conduction of the substrate is slow, so that the temperature in the module is easily increased, and the failure of the components is caused or accelerated. If the LTCC is combined with metal to form an LTCC/metal composite substrate (LTCC-M for short), the advantages of the LTCC can be fully exerted. At present, the combination of LTCC and metal substrate is realized by metallizing the surface to be combined of LTCC and then welding with the metal substrate (generally, AuSn welding is adopted). The welding reliability of the mode is not stable, in addition, the cost is higher, and the subsequent working temperature is limited.

With the continuous progress of modern communication and the rapid development of the microelectronic industry, electronic products gradually tend to be miniaturized and densified, the packaging density of the electronic products is also continuously improved, the requirement on heat dissipation is also increased, the traditional air cooling technology is not ideal for heat dissipation of high-heat-density chips, and compared with a micro-channel heat sink, the micro-channel heat sink has a better heat dissipation effect. The heat can be effectively transferred by using a single micro-channel. However, a single-layer micro flow channel built in a traditional LTCC substrate cannot effectively transfer heat generated by a heat source on the LTCC substrate, because the LTCC substrate has low thermal conductivity, the heat source generally exists on the surface of the substrate, and the heat generated by the heat source is difficult to transfer to fluid inside the substrate through the LTCC substrate with high thermal resistance. Not only the reduction of the working temperature of a typical heating power device becomes difficult, but also the traditional LTCC substrate single-layer micro-channel structure has self defects, so that the heat dissipation is uneven, and the requirement of the temperature uniformity of the SiP packaging assembly is difficult to achieve. In addition, the conventional LTCC substrate has weak fracture resistance and mechanical impact resistance, and the substrate is easy to crack or break and lose efficacy under the impact of larger load. Therefore, how to improve the forming quality of the novel LTCC substrate micro-flow channel becomes a difficult problem. For example: how to optimally regulate and control a ceramic-metal gradient functional interface layer embedded with a microstructure, how to construct a low-thermal-resistance high-reliability thermal interface, and how to solve the problems of roughness, collapse, blockage, substrate warpage, large stress and the like of the pipe wall of a micro-channel after the number of layers of the micro-channel in the LTCC substrate is increased. The method becomes a technical problem for solving the application of the micro-flow channel of the LTCC substrate on a certain SiP assembly. For example, in a power module, since there are a large number of SiP packages (200 SiP packages in the transmitting part and 900 SiP packages in the receiving part, the total power is 900W. only 200 SiP packages in the transmitting part are used for calculation, the total power is 500W, and the area of a single chip is 2 × 1mm ² The power is 2.5W, and the heat flow density is 125W/cm ² ) The packaging density is increased, the heat dissipation problem is obvious, the power density and the heat flux density are inevitably greatly increased, the junction temperature of a chip is increased, and the heat dissipation problem is causedThe reliability of the power MMIC is reduced, and serious consequences such as failure, burning and the like can be caused seriously. Meanwhile, the working temperature is greatly increased by a high-power load belt, and heat pipe control becomes an important problem which cannot be ignored, so that on one hand, the temperature of a chip needs to be controlled in a normal working range to improve the gain of the SiP packaging assembly; on the other hand, it is necessary to ensure that hundreds of SiP packages (including transmitting and receiving parts) are in phase with each other under the same temperature condition.

The LTCC material has low thermal conductivity and is only 3W/(m.K). Therefore, heat dissipation under the LTCC micro flow channel platform needs to face a problem of how to conduct the heat of the power chip to the micro flow structure. The LTCC substrate is manufactured and the performance of the LTCC substrate is controlled, and has a plurality of influencing factors and is relatively complex. The primary embodiment is that the microchannel structure needs to be sufficiently protected during lamination and sintering of the laminate, particularly during the lamination stage, to avoid fracture of the structure or fracture of the entire substrate. The uniformity of sintering shrinkage of large-area and multi-layer LTCC substrates has great influence on the yield and the product performance of the LTCC substrates. One of the key technologies for manufacturing LTCC substrates is sintering shrinkage control. The sintering shrinkage of the substrate is mainly controlled by controlling various factors influencing the sintering shrinkage, and the factors influencing the sintering shrinkage comprise the granularity of powder, the proportion of a casting adhesive, the pressure of a hot-pressing lamination, a sintering curve and the like.

The flatness of the LTCC substrate suffers from detrimental effects on other properties of the overall substrate (e.g., sensors, RF signal transmission and reception) and also affects the reliability of the overall monolithic system. Despite the advantages of LTCC, everything is not perfect, LTCC also has some disadvantages:

one is the problem of controlling shrinkage. Shrinkage control is one of the most main factors influencing the reliability of the LTCC embedded device, and the uniformity of sintering shrinkage of a large-area and multi-layer LTCC substrate has great influence on the yield and the product performance of the LTCC substrate. The sintering shrinkage of the substrate is mainly controlled by controlling various factors influencing the sintering shrinkage, and the factors influencing the sintering shrinkage comprise the granularity of powder, the proportion of a casting adhesive, the pressure of a hot-pressing lamination, a sintering curve and the like. During sintering of the multilayer LTCC, the shrinkage of the green tape in the horizontal X, Y direction is generally 12.2% to 16%, with an error of about 0.2%. The shrinkage in the thickness Z direction is generally about 15.3% to 25%, with a shrinkage error of about 0.5%. The width and the spacing of the metal wiring are very small, and can be as small as tens of microns, and excessive dislocation and deformation cannot be caused between layers during sintering, otherwise, the conductive gold wires cannot be aligned and cannot be connected, so that open circuit or short circuit of a circuit is caused, the performance of the module is seriously influenced, and even the module loses the function. In order to control the shrinkage problem, there are currently mainly several processes: self-constrained sintering (SCS), pressure-assisted sintering (PAS), pressureless sintering (PLAS), and co-sintering of composite panels. The second is the problem of chamber collapse. The LTCC substrate has a plurality of cavities on the surface and inside for embedding components, and the cavities can collapse during lamination, lamination and sintering to damage the components. The flatness of the LTCC substrate can also be compromised, affecting other module performance such as sensor accuracy, RF transceiver performance. For the heat dissipation of the micro-channel of the LTCC substrate, the size of the internal channel is relatively large, collapse is easy to occur, even the substrate is locally broken, liquid seepage can be possibly caused due to insufficient air tightness, the whole LTCC module is damaged, and the reliability of the whole system is also reduced. Fourthly, the number of external leads on the substrate per unit area is large due to the large number of I/Os and the high assembly efficiency while the absolute area of the substrate is large, so that the packaging of the substrate faces the difficult problems of reducing the overall dimension, improving the packaging efficiency and ensuring the number of I/Os. And (4) checking and adjusting the opening and benefiting speed and time of the rubber discharge stage, the opening and benefiting speed and time of the hospital joint stage, and closing the section to the qi conservation and the Lian worker B parameters. The structure of LTCC base plate also is the key factor of deciding LTCC base plate sintering warpage, when there is the cavity structure of multiple specification on the LTCC base plate, its structure is difficult to the equilibrium symmetry, simultaneously because contain a large amount of through-holes and intensive metal conductor on the LTCC base plate, these all are difficult to evenly distributed, just so lead to its warpage ultra-poor easily.

Protecting the blind cavity on the surface of the base plate, usually using an insert method, filling the insert in a cavity in a lamination stage, and taking out the insert after sintering; however, the insert cannot be removed after sintering from the chamber and the micro flow channel inside the substrate, and in this case, the sacrificial layer method is generally used, and the filled sacrificial layer is decomposed into gas to be exhausted during the sintering process. Thirdly, the mechanical strength is a problem. The LTCC is a brittle material, the tensile strength and the bending strength are low, the LTCC is easy to break under stress, the mechanical strength is poor, the flexural strength is 180MPa, and the flexural strength is far lower than that of Al2O3 and is 75-345 MPa. When the local temperature is too high, the deflection degree of the substrate is increased during the generated thermal deformation, the integrity of the substrate is influenced, and the performance of the module is deteriorated. It is necessary to consider the thermal deformation of the LTCC substrate in the thermal design stage. The metal has the advantages of high strength, good toughness, good heat and electric conductivity and the like, but has poor high-temperature corrosion resistance. The ceramic material has the characteristics of high temperature resistance, corrosion resistance and the like, but the brittleness is large, and because the expansion coefficients of the interface of the ceramic material and the interface are different, large thermal stress is often generated during bonding, so that peeling, falling and heat resistance reduction are caused, and the material is damaged.

With the development of miniaturization, high performance and multi-functionalization of electronic products, the packaging density is continuously increased, and the power consumption per unit area is continuously increased, resulting in an increasing temperature of the package. The over-high temperature not only reduces the working performance of the chip, burns out the device and breaks the connecting line, but also causes the problems of package body structure breakage, chip falling and the like due to the over-large temperature difference. In practical research, the micro-channel based on the LTCC substrate does not achieve the heat dissipation effect of a metal or alloy micro-channel, because the LTCC has low heat conductivity of only 2-5W/m.K, the heat conduction resistance between the chip shell and the fluid-solid coupling surface is large, and the heat cannot be taken away by liquid. The traditional LTCC ceramic-metal composite material has the problem of mismatch of physical properties on a two-phase interface, and due to the difference of thermal expansion coefficients between ceramics and metals in the composite material, under a service environment, particularly at an extremely high temperature, due to the difference of the thermal expansion coefficients of the two interfaces, large thermal stress is often generated during bonding, so that the separation, the falling and the reduction of the resistance to execution are caused, and the material is damaged. Therefore, the interlayer is easy to generate stress concentration under the action of temperature load to generate a delamination phenomenon, or cracks are initiated on an interface to weaken the performance of the material, so that residual stress is generated. Causing material damage, heat dissipation has become a core issue that limits chip packaging. A novel functional material, namely a gradient functional material FGM, is generated for various severe and harsh use environments. FGM requires that the elements (composition, structure, etc.) that make up the material vary continuously within the assembly space, thereby yielding a heterogeneous material with properties that vary continuously in geometric space. The gradient functional material (FGM) is a heterogeneous composite material, wherein the composition, structure, porosity and other factors of the material are continuously changed in a gradient manner or in a step manner along a certain direction of the material and the structure, so that the property and function of the material are continuously changed or in a step manner. The heterogeneous composite material can integrate different properties of various raw materials and has the functions of resisting and stress-bearing slow release.

The LTCC substrate multilayer micro-channel cavity is inevitably deformed after two procedures of high-pressure isostatic pressing and co-firing in the process of manufacturing. The isostatic pressing laminating process of the novel LTCC multilayer substrate is generally carried out for 9min under the water temperature of about 21MPa and 70 ℃, so that the novel LTCC multilayer substrate is hot-pressed to form a laminated substrate, the characteristic temperature curve of the novel LTCC substrate is not matched with the characteristic temperature curve of the novel LTCC substrate to be co-fired to generate cavity deformation and cavity dislocation morphology knot, and the cavity dislocation is mainly caused by residual thermal stress generated in the co-firing process and thermal stress strain generated in the post-firing process. Because the printing machine is adopted for screen printing, the granularity of the carbon black is required to be micron-sized, the large-particle carbon black needs to be subjected to ball milling in the actual processing process, but the diffusion in the printing process still exists, because the flow channel is arranged below each chip, the cold liquid in the flow channel is an inlet of the branch flow channel at the position close to the main flow channel, when the cold liquid reaches the middle position, the fluid absorbs a large amount of heat and is heated, the heat resistance of convective heat transfer is increased due to the increase of the temperature of the fluid, and the coefficient of convective heat transfer is reduced.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to meet the requirement of rapid and efficient heat pipe control by rapidly increasing the heat flow density of a certain SiP high-density three-dimensional integrated power module as soon as possible, and provides the heat pipe control micro-channel LTCC-M packaging substrate micro-channel structure and the manufacturing process method thereof, wherein the heat pipe control micro-channel LTCC-M packaging substrate micro-channel structure has uniform heat dissipation and high heat exchange efficiency, can effectively improve the heat dissipation capability, reduce the heat dissipation channel thermal resistance and obviously improve the bending resistance and mechanical impact resistance of the LTCC substrate micro-channel.

The above object of the present invention can be achieved by the following technical solutions: a thermally-controlled micro fluidic channel LTCC-M package substrate comprising: the heat source 4, the metal level 3 of setting on 1 face of LTCC metal composite substrate and the entry and the export that are located heat source 4 both sides, intercommunication the water pump runner 2 of entry and export, the perpendicular entry and the export of intercommunication down and form the microchannel topological structure of two-way perpendicular parallel cycle microchannel with the water pump pipeline, its characterized in that: a chip heat transfer channel 5 with an embedded chip is arranged in the LTCC substrate of the metal layer 3 below the heat source 4, and in the direction of a heat channel between the chip heat transfer channel 5 and the bidirectional parallel multilayer micro-channel 8, a multilayer micro-channel unit 8 which is integrated with the metal layer 3 heat exchange channel and has horizontal convection heat exchange and is linearly parallel and parallel in the metal structure blind cavity is arranged below the chip heat transfer channel, an array heat conduction metal micro-column 7 which is fixedly connected with the gradient function FGM material interface isolation layer 6 and is embedded in the LTCC ceramic layer 9 cavity, thereby forming a metal layer 3, a liquid cooling channel and heat transfer channel thermal interface convection heat exchange unit, and a liquid cooling channel and heat transfer channel thermal interface convection heat exchange unit through a heat exchange channel FGM material interface isolation layer 6 gradient heat exchange function interface-array metal microcolumn 7-multilayer micro channel unit 8-LTCC ceramic layer 9 ceramic interface-layer interconnection.

A process for manufacturing a thermal management control micro-channel LTCC-M packaging substrate comprises the steps of carrying out green ceramic tape casting, punching and lamination, selecting materials from the aspects of thermal expansion coefficient, elastic modulus and thermal conductivity matching, designing an interface matching structure from the aspects of thickness, size and layout parameters, designing an FGM functional layer from the aspects of pressure, speed, metal layer spraying temperature and speed process parameters of printing FGM, then, temperature distribution and thermal stress calculation are carried out according to the physical property parameters of the material and the distribution function of the gradient components, a component combination system and gradient distribution with the stress intensity ratio reaching the minimum value are solved, the method comprises the steps of printing a material of the FGM on the surface layer of the LTCC substrate, completing the solidification of an FGM functional layer after a solidification process, coating a metal material on the surface of the FGM, and sintering the LTCC substrate together after coating to form a metal-FGM-ceramic interface; the LTCC material of a Ferro A6M system is used as a radio frequency functional layer multilayer substrate medium, and multilayer micro-channel integrated manufacturing of a metal microstructure embedded in an LTCC substrate is realized through an LTCC multilayer manufacturing process, a metal microstructure embedded ceramic-metal interface integrated process and a micro-channel forming process; high-precision alignment between LTCC substrate layers is realized by a film-free process, a ceramic-metal interface is constructed, CuMoCu with a thermal expansion coefficient close to that of LTCC is selected as an LTCC substrate metal layer, interface combination is realized by an intermediate layer-gradient functional interface layer and an LTCC ceramic layer with a thermal expansion coefficient close to that of the metal layer and LTCC, a gradient functional interface layer material with sintering temperature higher than 850 ℃ and cofiring with the metal layer, the LTCC substrate and the LTCC ceramic layer is adopted, the LTCC ceramic layer and the metal layer are tightly combined under the action of the gradient functional interface layer, and a multilayer micro-channel cavity of the LTCC substrate is pressurized for at least 10min at the water temperature higher than 21MPa and 70 ℃ after two procedures of high-pressure isostatic pressing and cofiring in the process manufacturing process, so that the LTCC multilayer substrate is hot-pressed to form a laminated substrate; under the supporting action of a three-dimensional structure of a cavity at 600-850 ℃, carbon black paste which is a sacrificial material with micron-sized granularity is adopted to manufacture a graphic mask plate meeting the requirements of a screen printing scheme of a printing machine, a filling material is filled into the cavity, the cavity is printed and dried for multiple times to the required filling height and then sintered, large-particle carbon black is subjected to ball milling, the defects of the embedding cavity of the carbon-based sacrificial material are controlled, the step of annealing treatment is added to the co-fired substrate before post-sintering, and the post-sintering process is carried out after the substrate is annealed.

Compared with the prior art, the invention has the following beneficial effects:

the invention arranges a metal layer 3 of a convection heat exchange channel, a multi-layer micro-channel unit 8 which is horizontally convected and is linearly and parallelly arranged in a metal structure blind cavity, and a metal-gradient functional interface material FGM-contrast material of an embedded metal micro-column array on a low temperature co-fired multi-layer ceramic (LTCC) substrate in the direction of a heat channel between a chip and a bidirectional parallel circulation micro-channel, wherein the diffusion between the metal layer and the metal layer is diffused to a ceramic interface LTCC ceramic layer 4, thereby ensuring the continuity between layers, realizing different functions on two sides of the material by using the Functional Gradient Material (FGM), and overcoming the defect of unmatched performance of different material combining parts. Because FGM composition and performance have very big difference with traditional material, thermal property and mechanical properties along certain direction continuous variation and functional variety, compare with traditional LTCC base plate microchannel, proved can increase the area to the fluid heat transfer, can effectively promote heat-sinking capability and heat dissipation homogeneity, improved convection heat exchange efficiency. The FGM has excellent metal matrix interface compatibility, high flexibility, high reliability and gradient functionality, can prevent microcracks from generating, eliminate peeling phenomena and avoid structural damage or fracture of the whole substrate caused by fracturing. The multi-layer micro-channel units 8 which are horizontally convected and linearly and parallelly arranged in the metal structure blind cavity and the metal-gradient functional interface material FGM-ceramic interface LTCC ceramic layer embedded with the metal micro-column array can avoid the problems of roughness, collapse, blockage, substrate warpage, large stress and the like of the wall of the micro-channel. Through LTCC lower floor's base plate make the heat conduction through-hole passageway of high density in the microchannel, the heat radiation structure who designs can improve under the LTCC microchannel platform heat source area heat dissipation effectively and face this problem how the power chip heat conducts to the microflow structure in, and the temperature value can reduce along with the increase of loading heat dissipation flow gradually. Meanwhile, the problems of roughness, collapse, blockage, substrate warping, large stress and the like of the pipe wall of the micro-channel after the number of layers of the micro-channel in the LTCC substrate is large are solved. Meanwhile, the phase consistency of hundreds of SiP packaging assemblies under the same temperature condition is ensured. Carry out heat-conduction through flowing through the heat conduction microcolumn that embeds in the LTCC base plate, generate heat the chip below, dispel the heat through external heat exchange system, improved the heat convection coefficient, the heat-conduction heat dissipation of embedded metal microcolumn is obviously higher than the heat diffusion heat dissipation of the novel LTCC of tradition.

The invention provides a method for rapidly and efficiently controlling heat, which meets the requirement of rapidly increasing the heat flow density of a certain SiP high-density three-dimensional integrated power module, adopts a multilayer micro-channel structure with a metal microstructure embedded in an LTCC substrate and a metal micro-column array and a gradient functional interface of the LTCC substrate which are mutually connected layer by layer to form a heat transfer channel of a chip-metal layer-gradient functional interface layer-embedded array micro-column-liquid cooling channel and a novel heat interface of the chip-to increase the area for exchanging heat with fluid, and the array is mutually connected with a cavity and the gradient functional interface layer to form the heat transfer channel of the chip-metal layer-gradient functional interface layer-embedded array micro-column-liquid cooling channel, thereby achieving the purpose of effectively controlling heat. And the application of the metal layer and the gradient functional interface layer can obviously improve the bending resistance and the mechanical impact resistance of the micro-channel of the LTCC substrate. Because the LTCC substrate is embedded with the metal layer and the gradient functional interface layer on the chip heat transfer path, the capability of resisting bending and mechanical impact of the micro-channel of the LTCC substrate is obviously improved. The embedded metal microstructure and the multilayer micro-channel with high-efficiency heat transfer can ensure the stable heat control capacity of 900 SiP packaging assemblies.

The invention designs a metal layer, a gradient functional interface layer and an LTCC ceramic layer embedded with a metal micro-column array in the direction of a heat channel between an LTCC substrate chip and a micro-channel. The gradient functional interface material (FGM) solves the problem of interface stress of the composite material, and simultaneously maintains the composite property of the material. Whereas FGM does not produce a sudden change in the interface by gradually changing the volume fraction of the material composition. FGMs can operate at very high temperature gradients, maintain the structural integrity of their components, reduce thermal, residual and stress concentration coefficients, thereby eliminating interface problems and smoothing stress distributions. Therefore, the metal/ceramic FGM can not only fully exert the characteristics of good high temperature resistance and corrosion resistance of the ceramic, high strength and good toughness of the metal, but also well solve the problem of unmatched thermal expansion coefficients between the metal and the ceramic. The heat generated by the chip can be quickly and efficiently transferred into the liquid cooling channel through the metal layer and the like. The thermal resistance of the heat dissipation channel is reduced, and the purpose of effective thermal management is achieved. And the metal layer and the gradient functional interface layer can obviously improve the bending resistance and the mechanical impact resistance of the micro-channel of the LTCC substrate.

Aiming at the key process difficulty of the micro-channel of the LTCC substrate, the structure from the heat source to the heat channel is simulated according to the structure of the micro-channel heat dissipation exchange system and by combining the aspects of the limitation of the LTCC process level, such as the arrangement distribution of metal through holes from the heat source to the multilayer micro-channel, the multilayer micro-channel structure, the channel cavity structure thereof, the fluid flow rate, the channel pressure, the shape deformation and the like, so that the size distribution of the heat conduction micro-column and the channel cavity structure is obtained. The technical problems of interlayer alignment of a multilayer LTCC substrate, integrated manufacturing of a ceramic-metal interface with an embedded metal microstructure, forming of the multilayer micro-channel of the LTCC substrate and the like are mainly solved through a technical approach of integrated manufacturing of the multilayer micro-channel LTCC with the embedded metal microstructure. The chip-metal layer convective heat exchange-FGM-LTCC ceramic layer gradient functional interface layer-embedded micro-column array-liquid cooling channel embedded in the LTCC substrate and the thermal interface process design of the chip, the integrated manufacturing process of the multilayer micro-channel with the metal microstructure embedded in the LTCC substrate, the defect control of the multilayer micro-channel with the metal microstructure embedded in the LTCC substrate and other key technologies break through, so that the problem that the physical properties of the traditional LTCC ceramic-metal composite material are mismatched on two phase interfaces is solved. The microfluidic heat dissipation channel is integrated inside the LTCC substrate, and particularly below a high-power device assembled on the LTCC substrate, the heat dissipation characteristic of the LTCC substrate can be effectively improved. The high-density heat conduction hole manufacturing with the local hole proportion as high as 50% is realized by combining the high-density heat conduction through hole technology and the micro-channel manufacturing technology. The test result proves that the LTCC microflow system has the heat dissipation capacity of not less than 50W/c square meter. The application range of the LTCC substrate in the technical fields of microwave power assemblies and LTCC-SIP can be expanded. The LTCC substrate micro-channel structure is embedded with a metal micro-structure and a multi-layer micro-channel with high-efficiency heat transfer, and can ensure the stable heat pipe control capability of 900 SiP packaging assemblies. Compared with the traditional heat dissipation mode, the heat dissipation device has good heat dissipation effect.

The invention takes the LTCC/metal composite substrate into consideration as a whole, and aims at the micro-channel structure of the LTCC substrate, and respectively performs the functions of heat dissipation and reinforcement by utilizing the metal layer with higher thermal conductivity, better mechanical strength and thermal expansion coefficient similar to that of the LTCC substrate from the ceramic-metal key process with the embedded metal microstructure, the integrated manufacturing key process and the defect control key process. Although it is difficult to directly bond the LTCC ceramic to the metal layer with respect to the ceramic-metal interface construction, the present invention is achieved by an intermediate layer-gradient functional interface layer. The gradient functional interface layer can be well combined with the metal layer and the LTCC ceramic layer. The gradient functional interface material (FGM) is co-fired with the metal layer and the LTCC ceramic layer (the sintering temperature is about 850 ℃) to form the gradient functional interface layer material, the components or the structure are gradually changed in a continuous and step-by-step mode, the performance of the composite material is changed, a continuous gradient is created, and the gradient integrated manufacturing of the ceramic-metal interface with the embedded metal microstructure is realized. The FGM has similar thermal expansion coefficient heat conduction with the metal layer and the LTCC substrate, has higher chemical stability, thermal stability, mechanical strength and the like after being sintered, and can ensure that the LTCC ceramic layer and the metal layer are tightly combined under the action of a gradient functional interface layer, thereby reducing the heat transfer resistance of ceramic-metal and improving the reliability. Three-dimensional structural support during lamination and sintering; the sacrificial material is matched with the TCE of the LTCC substrate, and the sacrificial material does not cause pressure on the cavity during sintering; easy to remove (by decomposition or other means) after sintering. Firstly, the residual stress generated in the co-firing process is reduced, and secondly, the thermal stress generated in the post-firing process is reduced.

The high-precision alignment between the LTCC substrate layers is realized by a film-free process, and more stress can be released by the film-free process, so that the alignment precision between the layers is improved. The manufacturing process is one-step sintering molding, has high printing precision, can meet the requirements of large current and high temperature resistance, and has excellent heat conductivity compared with the common PCB circuit substrate. Better temperature characteristics, such as a lower Coefficient of Thermal Expansion (CTE), a lower temperature coefficient of resonance frequency.

The invention takes the substrate of the microcircuit or the assembly as a packaging carrier, leads out the 1/0 terminal of the package directly on the substrate and is connected with other parts of the packaging body, so that the substrate and the shell form a packaging whole, and the packaging problem of high-density integrated complex MCM-C can be better solved.

Drawings

In order to more clearly illustrate the technical solution in the present embodiment, the drawings needed to be used in the description of the embodiment will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present embodiment, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.

Fig. 1 is a schematic diagram of a thermal control micro flow channel LTCC package substrate according to the present invention.

FIG. 2 is a schematic diagram of an alternative embodiment of the size and distribution of the embedded array thermally conductive metal micropillar structures of FIG. 1;

FIG. 3 is a process flow diagram for fabricating a thermally controlled micro fluidic channel LTCC-M package substrate;

in the figure: the chip comprises an LTCC-M packaging substrate, a water pump flow channel, a metal layer, a heat source, a chip heat transfer channel, an FGM material interface isolation layer, an array heat conduction metal microcolumn, a multilayer micro-flow channel unit and an LTCC ceramic layer, wherein the LTCC-M packaging substrate comprises a chip body, a water pump flow channel, a chip body and a heat source, the chip body comprises a chip body and a chip body, the chip body comprises a chip body, the chip body is made of a ceramic material, the LTCC-M ceramic layer is arranged on the chip body, the chip body is made of a ceramic material, and the LTCC-M ceramic layer is arranged on the chip body.

The technical solution of the present embodiment is described in detail with reference to the accompanying drawings and specific embodiments.

Detailed Description

See fig. 1. In a preferred embodiment described below, a thermally controlled micro fluidic channel LTCC-M package substrate comprises: the heat source 4, the metal level 3 of setting on 1 face of LTCC metal composite substrate and the entry and the export that are located heat source 4 both sides, intercommunication the water pump runner 2 of entry and export, the perpendicular entry and the export of intercommunication down and form the microchannel topological structure of two-way perpendicular parallel cycle microchannel with the water pump pipeline, its characterized in that: a chip heat transfer channel 5 with an embedded chip is arranged in an LTCC substrate of a metal layer 3 below a heat source 4, a plurality of micro-channel units 8 which are linearly parallel and are horizontally convective heat exchange and are compounded into a whole by the metal layer 3 heat exchange channel are arranged below the chip heat transfer channel 5 in the direction of a heat channel between the chip heat transfer channel 5 and a bidirectional parallel multi-layer micro-channel 8, and array heat-conducting metal micro-columns 7 which are fixedly connected with a gradient function FGM material interface isolation layer 6 and are embedded in a cavity of an LTCC ceramic layer 9 are arranged in parallel in a metal structure blind cavity, so that the metal layer 3 heat exchange channel is formed by interconnecting a gradient heat exchange function interface-array metal micro-column 7-a plurality of micro-channel units 8-LTCC ceramic layer 9 through the heat exchange channel FGM material interface isolation layer 6 layer by layer, a liquid cooling channel, a heat control unit for convective heat exchange of the heat interface of the heat transfer channel, the liquid cooling channel, a liquid cooling channel, And the heat transfer channel thermal interface is used for heat exchange of convection heat.

The heat generated by the heat source 4 is transferred, part of passive elements and metalized wiring and through hole metalized chips which are integrated in the cavity of the metal layer 3 and the lamination are filled with the 'FGM insert' in the LTCC blind cavity manufacturing, the heat load of the hot chip on the upper surface of the LTCC substrate is used for simulating a heat source needing heat dissipation, through mutual fusion of diffusion on a molecular scale, a seamless object and the rheological property of stress distribution of a continuous gradual change cellulose-based material at an interface are formed, and the heat flow density gradient information of the multi-layer micro-channel unit 8 is obtained by utilizing high contrast and multi-dimensional rigidity gradient; the cooling fluid flows in from the inlet, flows through the main flow channel at the shunt outlet of the parallel branch flow channels along the path, and flows out from the outlet.

The cold flow of the liquid cooling channel is in convection heat exchange, the heat diffusion and heat dissipation of the heating chip and the LTCC are conducted by flowing through the array heat-conducting metal microcolumn 7 embedded below the FGM material interface isolation layer 6, the heat generated by the chip is rapidly cooled by the convection heat exchange of the metal layer 3, and the parallel channels of the multi-layer micro-channel units 8 in the blind cavity below the array heat-conducting metal microcolumn 7 are rapidly and efficiently transferred into the liquid cooling channel, so that the heat is dissipated through an external heat exchange system.

In an alternative embodiment, heat exchange flow channels with metal microstructures are formed in the broadside direction of the metal layer 3, and the heat exchange flow channels are arrayed in parallel along the broadside direction of the metal layer 3. As shown in fig. 2, the array heat-conducting metal micropillars 7 of the LTCC ceramic layer 9 may be made of gold paste, and the parameters and distribution may be designed into a matrix arrangement with equidistant pitch arrangement, or an isosceles triangle with b as the first side and c as the waist, and a dot-shaped array arrangement matrix with 45-degree cross arrangement, and dot-shaped linear arrays forming a dot-shaped array arrangement matrix with staggered mixed arrangement of dot-shaped isosceles triangles at intervals.

In the calculation of temperature distribution and thermal stress, firstly, giving the condition of one-to-one correspondence reversibility of random variable moment mother function M(s) and distribution function, then utilizing the re-expectation rule to give the distribution of linear operation, division and product of discrete and continuous random variables which are mutually independent, bringing the coefficient value into the discrete distribution function, converting the coefficient value into discrete cumulative function and continuous cumulative function, differentiating to obtain density function, deducing the distribution function and probability density function of the density function to obtain the moment mother function of the sum of a plurality of random mutually independent random variables, and inverting the moment mother function to obtain the corresponding distribution function F (X) ═ P { X ≦ X }. Where X is a random variable and X is any real number.

The random variable X takes two values of 0 and 1, and the distribution law is P { X ═ k } ═ P (1-P)1-k, k ═ 0,1, 0<p<1, X is said to obey a 0-1 distribution with p as a parameter. Assuming that all possible values of the random variable X are 0,1,2,3, … and the probability of taking each value is 2e-2, then P { X ═ k } ═ λ ^k e ^-λ K, k ═ 0,1,2,3>0 is a constant, and X is said to obey Poisson distribution with parameter λ, and is denoted as X- π (λ).

According to the influence of the current processing technology and the microcavity on the performance of the substrate, in order to avoid the design and processing of a multilayer micro-channel structure which causes the surface layer of the substrate to collapse, the LTCC substrate is designed according to the novel LTCC substrate perforating process and the temperature gradient distribution, the heat source chip is placed on the upper surface of the substrate, four layers of green ceramic chips are reserved on the surface of the substrate and are formed by sintering 25 layers of green ceramic chips, wherein 1-4 layers of green ceramic chips are solid layers and mainly embed some passive devices and active devices, 5-17 are flow channel layers, 18-25 are inlet and outlet adjusting layers, and after the LTCC substrate is sintered, the LTCC size is as follows: the length and Width (WL) is not less than 60mm, the thickness (H) is not less than 8mm, and the thickness of each layer of the flow channel layer is not less than 200 um.

The micro-channel structure adopts ANSYS software to model and simulate single-layer micro-channels of six common structures, namely a direct-insert micro-channel, an Archimedes rectangular spiral micro-channel, a snake-shaped curve micro-channel, an H-shaped micro-channel and a tree-shaped micro-channel, and the LTCC multilayer micro-channel section structure is prefabricated according to the substrate temperature distribution of the micro-channels with different structures under different chip powers, the speed distribution and the pressure distribution of fluid in the channels; a spiral single-layer micro-channel structure; a snake-shaped curve single-layer micro-channel structure; according to the three-dimensional distribution of the heat source heat flow density, a finite element simulation method is adopted to simulate and calculate the thermal coupling and stress strain states of the structure of the micro-channel in a thermal fatigue state aiming at 3 common structures of the straight-inserting type micro-channel, the spiral type and the serpentine type, according to the multi-layer interconnection combination of different single-layer micro-channels, the liquid flow speed of a multi-layer micro-channel cavity and the change rule of chip power are obtained, and one of the straight-inserting type micro-channel, the spiral type and the serpentine type is selected as the micro-channel structure.

Aiming at the key process problems in the LTCC process, in the process of manufacturing the heat control micro-channel LTCC-M packaging substrate, infrared laser with the wavelength of 964nm is adopted to punch holes on a metal layer 3 and an FGM material interface isolation layer 6, grooves arrayed in parallel along the wide edge are cut on the metal layer 3, a laser and mechanical combined processing mode is adopted, a laser cutting machine is firstly used for punching water pump channels 2 on two sides of an LTCC/metal composite substrate 1, multilayer micro-channels are roughly cut on a raw ceramic tape, a CNC milling cutter is used for finely processing the channels to form a multilayer micro-channel structure meeting the smooth requirement of fluid flow, a self-propagating high-temperature synthesis method is adopted for filling element powder and metal powder forming an FGM compound according to gradient composition, static molding is placed into a reaction container, ignition and combustion is carried out at one end, and forward propagation is carried out through reverse propagation, forming a molten pool on the surface of the substrate, synthesizing a layered structure with gradually changed components or grain size gradient along the section, generating an intermetallic compound gradient functional material, and preparing the FGM with a reinforcing phase in gradient distribution and consisting of a reaction product and a metal functional material.

See fig. 3. According to the invention, a green ceramic tape co-firing process is generated by tape casting, after a three-dimensional structure is formed by tape casting, punching and lamination of LTCC green ceramics, material selection is carried out from the aspects of thermal expansion coefficient, elastic modulus and thermal conductivity matching, interface matching structure design is carried out from thickness, size and layout parameters, FGM functional layer design is carried out from pressure, speed, metal layer spraying temperature and speed process parameters of printing FGM, through the material printing of FGM on the surface layer of an LTCC substrate, the diffusion of molecules on the filament boundary is promoted and continuous gradient is generated based on the combination of polymer manufacturing materials, multi-dimensional continuous rigidity gradient is created, a multi-layer green ceramic layer is manufactured by using a hot-pressing lamination machine under different pressures and temperatures after the curing process, and the relation between the sintering shrinkage and the hot-pressing temperature and pressure is measured after sintering; after the solidification of the FGM functional layer is finished, coating a metal material on the surface of the FGM, and sintering the LTCC substrate together to form a metal-FGM-ceramic interface; the LTCC material of a Ferro A6M system is used as a radio frequency functional layer multilayer substrate medium, and multilayer micro-channel integrated manufacturing of a metal microstructure embedded in an LTCC substrate is realized through an LTCC multilayer manufacturing process, a metal-ceramic interface integrated process of the embedded metal microstructure and a micro-channel forming process; high-precision alignment between LTCC substrate layers is realized by a membrane-free process, a metal-ceramic interface is constructed, CuMoCu with a thermal expansion coefficient close to that of LTCC is selected as a metal layer composite LTCC substrate, interface combination is realized by an intermediate layer-FGM gradient functional interface layer and an LTCC ceramic layer with a thermal expansion coefficient close to that of the metal layer and LTCC, sintering temperature is 750-850 ℃ and pressure is 20-25Mpa in a sintering stage, and the LTCC substrate, the LTCC metal layer composite substrate and the LTCC ceramic layer are subjected to cofiring crystallization and devitrification reaction, and the gas flow in each stage is optimized by optimizing a sintering curve, so that the unmatched stress of the thermal expansion coefficients of different materials is relieved, and important process parameters such as the temperature rise rate and time in the stage, the temperature rise rate and time in the sintering stage, the air flow in each stage and the like are adjusted, so that the LTCC ceramic layer and the metal layer are tightly combined under the action of a gradient functional interface layer material FGM, the LTCC metal layer composite substrate multilayer micro-channel cavity is subjected to two procedures of high-pressure, isostatic pressing and co-firing in the process of manufacturing, and then is pressurized for at least 9min at the water temperature of more than 21MPa and 70 ℃, so that the LTCC multilayer substrate is hot-pressed to form a laminated substrate.

Under the supporting action of a three-dimensional structure of a cavity of the LTCC metal layer composite substrate at 600-800 ℃, a carbon black paste which is a sacrificial material with micron-sized granularity is adopted to manufacture a graphic mask plate meeting the requirements of a screen printing scheme of a printing machine, a filling material is filled into the cavity, the pattern mask plate is printed and dried for multiple times to a required filling height and then sintered, large-grained carbon black is subjected to ball milling, the defect of the embedded cavity of the carbon-based sacrificial material is controlled, the step of annealing treatment is added to the co-fired substrate before post-sintering, and the post-sintering process and lamination are carried out after the substrate is annealed.

It should be understood that the specific features in the embodiment and the embodiments are detailed descriptions of the technical solutions in the embodiment, but are not limited to the technical solutions in the embodiment, and the technical features in the embodiment and the embodiments may be combined with each other without conflict.

Claims

1. A thermally-controlled micro fluidic channel LTCC-M package substrate comprising: the heat source (4), metal level (3) of setting on LTCC metal composite substrate (1) face with be located the entry and the export on heat source (4) both sides, the intercommunication the water pump runner (2) of entry and export, the perpendicular intercommunication entry and export down and with the water pump pipeline form two-way perpendicular parallel cycle miniflow channel's miniflow channel topological structure, its characterized in that: a chip heat transfer channel (5) with an embedded chip is arranged in an LTCC substrate of a metal layer (3) below a heat source (4), a plurality of micro-channel units (8) which are linearly parallel and parallel in a metal structure blind cavity and are horizontally convective heat transfer compounded into a whole by the metal layer (3) heat transfer channels are arranged below the chip heat transfer channel (5) in the direction of a heat channel between the chip heat transfer channel and a bidirectional parallel multi-layer micro-channel (8), and array heat conduction metal micro-pillars (7) which are fixedly connected with a gradient functional FGM material interface isolation layer (6) and embedded in a cavity of an LTCC ceramic layer (9) are formed, so that the metal layer (3) heat transfer channel is formed by interconnecting the gradient heat transfer functional interface-array metal micro-pillars (7) -the multi-micro-channel units (8) -the LTCC ceramic layer (9) ceramic interface layer by layer, and the heat pipe control unit is used for carrying out convection heat exchange on the thermal interfaces of the liquid cooling flow passage and the heat transfer passage.

2. The thermally managed micro fluidic channel LTCC-M package substrate of claim 1, wherein: the heat generated by the heat source ()4 is transferred, part of passive elements and chips integrated in the cavity of the metal layer ()3 are used for simulating the heat source needing heat dissipation by virtue of 'FGM inserts' filled in the LTCC blind cavity manufacturing, the heat load of the heat chip on the upper surface of the LTCC substrate is mutually fused by diffusion on a molecular scale to form the rheological property of stress distribution at the interface of a seamless object and a continuous gradual change cellulose base material, and the heat flow density gradient information of the multi-layer micro-channel unit 8 is obtained by utilizing high contrast and multi-dimensional rigidity gradient; the fluid flows in from the inlet, flows through the main runner at the shunt outlet of the parallel branch runners along the path, and flows out from the outlet.

3. The thermally managed micro fluidic channel LTCC-M package substrate of claim 1, wherein: the cold flow of the liquid cooling channel is in convection heat exchange, the heat diffusion and heat dissipation of the heating chip and the LTCC are conducted by flowing through the array heat-conducting metal microcolumn ()7 embedded below the FGM material interface isolation layer ()6, the heat generated by the chip is rapidly cooled by convection heat exchange through the metal layer ()3, and the heat is rapidly and efficiently transferred to the liquid cooling channel through the parallel channels of the multilayer micro-channel unit ()8 in the blind cavity below the array heat-conducting metal microcolumn ()7, and is dissipated through an external heat exchange system.

4. The thermally managed micro fluidic channel LTCC-M package substrate of claim 1, wherein: the metal layer ()3 is provided with heat exchange channels of the metal microstructures in the width direction, and the heat exchange channels are arranged in parallel along the width direction of the metal layer 3.

5. The thermally managed micro fluidic channel LTCC-M package substrate of claim 1, wherein: the array heat-conducting metal microcolumn ()7 of the LTCC ceramic layer ()9 is made of gold slurry, and the parameters and distribution design are arranged in a matrix array which is arranged at equal intervals or in an isosceles triangle with b as the first side and c as the waist, and the matrix array is arranged in a dot-shaped array which is arranged in a 45-degree crossed manner, and the dot-shaped linear arrays are arranged in a dot-shaped array which is arranged in a dot-shaped isosceles triangle staggered and mixed manner at intervals.

6. The thermally managed micro fluidic channel LTCC-M package substrate of claim 1, wherein: the LTCC substrate is designed according to the novel LTCC substrate perforating process and the temperature gradient distribution, the heat source chip is placed on the upper surface of the substrate, four layers of green ceramic chips are reserved on the surface of the substrate and are sintered by 25 layers of green ceramic chips, wherein 1-4 layers of green ceramic chips are solid layers and mainly embed passive devices and active devices, 5-17 layers are flow channel layers, 18-25 layers are inlet and outlet adjusting layers, and after the LTCC substrate is sintered, the LTCC size is as follows: the length and width WL is more than or equal to 60mm, the thickness H is more than or equal to 8mm, and the thickness of each layer of the flow channel layer is more than or equal to 200 um.

7. The thermally managed micro fluidic channel LTCC-M package substrate of claim 1, wherein: the micro-channel structure adopts ANSYS software to model and simulate single-layer micro-channels of six common structures, namely a direct-insert micro-channel, an Archimedes rectangular spiral micro-channel, a snake-shaped curve micro-channel, an H-shaped micro-channel and a tree-shaped micro-channel, and the LTCC multilayer micro-channel section structure is prefabricated according to the substrate temperature distribution of the micro-channels with different structures under different chip powers, the speed distribution and the pressure distribution of fluid in the channels; a spiral single-layer micro-channel structure; a snake-shaped curve single-layer micro-channel structure; according to the three-dimensional distribution of the heat source heat flow density, a finite element simulation method is adopted for 3 common structures of a straight-insertion type micro-channel, a spiral type and a serpentine type, a sequential coupling method is adopted for simulating and calculating the structure thermal coupling and stress strain states of the micro-channel structure in a thermal fatigue state, according to the multi-layer interconnection combination of different single-layer micro-channels, the liquid flow rate of a multi-layer micro-channel cavity and the chip power change rule are obtained, and one of the straight-insertion type micro-channel, the spiral type and the serpentine type is selected as the micro-channel structure.

8. A process for manufacturing a thermal management control micro-channel LTCC-M packaging substrate comprises the steps of carrying out green ceramic tape casting, punching and lamination, selecting materials from the aspects of thermal expansion coefficient, elastic modulus and thermal conductivity matching, designing an interface matching structure from the aspects of thickness, size and layout parameters, designing an FGM functional layer from the process parameters of pressure, speed, metal layer spraying temperature and speed of printing FGM, then, temperature distribution and thermal stress calculation are carried out according to the physical property parameters of the material and the distribution function of the gradient components, a component combination system and gradient distribution with the stress intensity ratio reaching the minimum value are solved, the method comprises the steps of printing a material of the FGM on the surface layer of the LTCC substrate, completing the solidification of an FGM functional layer after a solidification process, coating a metal material on the surface of the FGM, and sintering the LTCC substrate together after coating to form a metal-FGM-ceramic interface; the LTCC material of a Ferro A6M system is used as a radio frequency functional layer multilayer substrate medium, and multilayer micro-channel integrated manufacturing of a metal microstructure embedded in an LTCC substrate is realized through an LTCC multilayer manufacturing process, a metal microstructure embedded ceramic-metal interface integrated process and a micro-channel forming process; high-precision alignment between LTCC substrate layers is realized by a film-free process, a ceramic-metal interface is constructed, CuMoCu with a thermal expansion coefficient close to that of LTCC is selected as an LTCC substrate metal layer, interface combination is realized by an intermediate layer-gradient functional interface layer and an LTCC ceramic layer with a thermal expansion coefficient close to that of the metal layer and LTCC, a gradient functional interface layer material with sintering temperature higher than 850 ℃ and cofiring with the metal layer, the LTCC substrate and the LTCC ceramic layer is adopted, the LTCC ceramic layer and the metal layer are tightly combined under the action of the gradient functional interface layer, and a multilayer micro-channel cavity of the LTCC substrate is pressurized for at least 10min at the water temperature higher than 21MPa and 70 ℃ after two procedures of high-pressure isostatic pressing and cofiring in the process manufacturing process, so that the LTCC multilayer substrate is hot-pressed to form a laminated substrate; under the supporting action of a three-dimensional structure of a cavity at 600-850 ℃, carbon black paste which is a sacrificial material with micron-sized granularity is adopted to manufacture a graphic mask plate meeting the requirements of a screen printing scheme of a printing machine, a filling material is filled into the cavity, the cavity is printed and dried for multiple times to the required filling height and then sintered, large-particle carbon black is subjected to ball milling, the defects of the embedding cavity of the carbon-based sacrificial material are controlled, the step of annealing treatment is added to the co-fired substrate before post-sintering, and the post-sintering process is carried out after the substrate is annealed.

9. The process of fabricating a thermally controlled micro fluidic channel LTCC-M package substrate of claim 7, wherein: in the process of manufacturing the heat control micro-channel LTCC-M packaging substrate, infrared laser with the wavelength of 964nm is adopted to punch holes on a metal layer ()3 and an FGM material interface isolation layer 6, grooves which are arrayed in parallel along the wide edge are cut on the metal layer 3, a laser and mechanical combined processing mode is adopted, a laser cutting machine is firstly used for punching water pump channels ()2 on two sides of an LTCC/metal composite substrate 1, a plurality of layers of micro-channels are roughly cut on a raw ceramic tape, and a CNC milling cutter is used for finely processing the channels to obtain a multi-layer micro-channel structure meeting the fluid flow requirement; and adopting a self-propagating high-temperature synthesis method to fill the element powder and the metal powder which form the FGM compound according to the gradient composition, statically forming, putting into a reaction container, igniting and burning at one end, forming a molten pool on the surface of a substrate by backward forward propagation, synthesizing a layered structure with gradually-changed components or grain size gradient along the section, generating the intermetallic compound gradient functional material, and preparing the FGM with the reinforced phase in gradient distribution and the reaction product and the metal functional material.

10. The process for fabricating a thermally controlled micro fluidic channel LTCC-M package substrate as claimed in claim 7, wherein a green tape co-firing process is generated by tape casting, after LTCC green porcelain is subjected to tape casting, punching and lamination to form a three-dimensional structure, material selection is carried out from the aspects of thermal expansion coefficient, elastic modulus and thermal conductivity matching, interface matching structure design is carried out from the aspects of thickness, size and layout parameters, FGM functional layer design is carried out from the process parameters of pressure, speed, metal layer spraying temperature and speed of printing FGM, the method comprises the steps of (1) printing materials of FGM on the surface layer of an LTCC substrate, combining manufacturing materials based on polymers, promoting the diffusion of molecules on the boundary of a filament and generating continuous gradient, creating multi-dimensional and continuous rigidity gradient, preparing a multi-layer green ceramic layer by using a hot-pressing lamination machine under different pressures and temperatures after a curing process, and measuring the relationship between the sintering shrinkage rate and the hot-pressing temperature and pressure after sintering; after the solidification of the FGM functional layer is finished, coating a metal material on the surface of the FGM, and sintering the LTCC substrate together to form a metal-FGM-ceramic interface; the LTCC material of a Ferro A6M system is used as a radio frequency functional layer multilayer substrate medium, and multilayer micro-channel integrated manufacturing of a metal microstructure embedded in an LTCC substrate is realized through an LTCC multilayer manufacturing process, a metal-ceramic interface integrated process of the embedded metal microstructure and a micro-channel forming process; high-precision alignment between LTCC substrate layers is realized by a membrane-free process, a metal-ceramic interface is constructed, CuMoCu with a thermal expansion coefficient close to that of LTCC is selected as a metal layer composite LTCC substrate, interface combination is realized by an intermediate layer-FGM gradient functional interface layer and an LTCC ceramic layer with a thermal expansion coefficient close to that of the metal layer and LTCC, sintering temperature is 750-850 ℃ and pressure is 20-25Mpa in a sintering stage, and the LTCC substrate, the LTCC metal layer composite substrate and the LTCC ceramic layer are subjected to cofiring crystallization and devitrification reaction, and the gas flow in each stage is optimized by optimizing a sintering curve, so that the unmatched stress of the thermal expansion coefficients of different materials is relieved, and important process parameters such as the temperature rise rate and time in the stage, the temperature rise rate and time in the sintering stage, the air flow in each stage and the like are adjusted, so that the LTCC ceramic layer and the metal layer are tightly combined under the action of a gradient functional interface layer material FGM, the LTCC metal layer composite substrate multilayer micro-channel cavity is subjected to two procedures of high-pressure, isostatic pressing and co-firing in the process of manufacturing, and then is pressurized for at least 10min at the water temperature of more than 21MPa and 70 ℃, so that the LTCC multilayer substrate is hot-pressed to form a laminated substrate.