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

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

Thermal management micro-channel LTCC-M package substrate and its manufacturing method

technical field

The invention relates to the application field of microwave and millimeter wave, and is widely used in a micro-system for realizing high-density integration in a system-in-package (SIP) of LTCC. Specifically, it relates to a thermal management control micro-channel LTCC-M package substrate and a manufacturing process method thereof.

Background technique

Low temperature co-fired ceramics (LTCC) have excellent properties and are an important part of modern microelectronic packaging, not only in microwave and millimeter wave applications. And it is widely used in high-speed, high-frequency systems. The LTCC multi-layer substrate technology can make up to dozens of layers of circuit substrates. The LTCC substrate can be embedded (buried) passive components, and some passive components can be integrated into the substrate, which is conducive to the miniaturization of the system and improves the circuit assembly. density and system reliability. Because the low temperature co-fired ceramic LTCC substrate has the advantages of high number of wiring layers, small square resistance of wiring conductors, low dielectric constant, and low sintering temperature, multiple chips with different functions, different powers, and different frequencies can be packaged together. The integration of passive components is realized, and multiple resistors, capacitors and inductors are embedded inside the substrate, which frees up a lot of space on the surface of the substrate for assembling other components. Microsystems that can achieve high-density integration in LTCC-based system-in-package (SIP) applications have become a viable implementation solution for ceramic monolithic integrated systems. Therefore, LTCC is widely used in electronic equipment. However, the poor thermal conductivity of LTCC results in that the heat generated by the operation of integrated power devices on the LTCC substrate cannot be dissipated quickly and in a timely manner, which becomes a weak point that limits the application of LTCC in high-power microwave components and multi-functional microsystems. Moreover, with the rapid development of electronic equipment, it presents the characteristics of miniaturization in size, complex structure, high assembly density, and high power. question.

Although LTCC substrates can give full play to the performance advantages of large-scale integrated circuits and high-speed integrated circuits, the integration of hybrid integrated circuits can be higher, and hybrid large-scale integrated circuits (HLSI) can be realized. However, LTCC is a glass/ceramic product, and its actual flexural strength is generally less than 200Mpa, and its mechanical impact resistance is not very large. Under a slightly larger impact, the substrate is prone to cracks or breaks, causing the circuit to fail. Due to the small thermal conductivity of LTCC, it is generally 2 to 3w/(m·k). When there are power components in the circuit, the heat conduction of the substrate is slow, which can easily cause the temperature in the module to rise, causing or accelerating the failure of the components. If LTCC is combined with metal to make LTCC/metal composite substrate (LTCC-M for short), the advantages of LTCC can be fully utilized. At present, the way to realize the combination of the LTCC and the metal substrate is to first metallize the surface to be combined of the LTCC, and then weld with the metal substrate (usually AuSn welding is used). The welding reliability of this method is not very stable, in addition, the cost is high, and the working temperature of the rear channel is limited.

With the continuous progress of modern communications and the rapid development of the microelectronics industry, electronic products are gradually tending to be miniaturized and high-density, and their packaging density is also increasing, and the requirements for heat dissipation are also increasing. The heat dissipation of the density chip is not ideal, in contrast, the micro-channel heat sink has a better heat dissipation effect. The heat can be efficiently transferred by means of a single microfluidic channel. However, the built-in single-layer micro-channels in the traditional LTCC substrate cannot effectively transfer the heat generated by the heat source on the LTCC substrate. This is because the thermal conductivity of the LTCC substrate is very low, and the heat source generally exists on the surface of the substrate, and the heat generated by the heat source is very high. Difficult to transfer into the fluid inside the substrate through the high thermal resistance LTCC substrate. Not only does it become difficult to reduce the operating temperature of typical heat-generating power devices, but also due to the inherent defects of the traditional LTCC substrate single-layer microchannel structure, it will lead to uneven heat dissipation, so it is difficult to meet the temperature uniformity requirements of SiP package components. In addition, the use of traditional LTCC substrates has weak resistance to bending and mechanical impact, and the substrate is prone to cracks or fracture failures under large load impact. Therefore, how to improve the molding quality of the new LTCC substrate microchannel has become a difficult problem. For example: how to optimize and control the ceramic-metal gradient functional interface layer with embedded microstructure, how to build a thermal interface with low thermal resistance and high reliability, and how to solve the problem that after the number of microchannel layers in the LTCC substrate is increased, the wall of the microchannel appears Defect problems such as roughness, collapse, blockage, substrate warpage, and high stress. It has become a technical problem to solve the application of LTCC substrate micro-channel in a certain SiP component. For example, for a power module, due to the existence of a large number of SiP package components (200 SiP package components in the transmitting part and 900 SiP package components in the receiving part, the total power is 900W. Only the 200 SiP package components in the transmitting part are used for calculation, its The total power is 500W, the area of a single chip is 2×1mm ² , the power is 2.5W, and the heat flux density is 125W/cm ² ), which leads to an increase in assembly density and a prominent heat dissipation problem, which will inevitably lead to its power density and heat flux. The density is greatly increased, resulting in an increase in the junction temperature of the chip, resulting in a reduction in the reliability of the power MMIC, and serious consequences such as failure and burnout. At the same time, the high-power load has brought about a significant increase in the operating temperature, and thermal management has become an important issue that cannot be ignored. On the one hand, it is necessary to control the chip temperature within the normal working range to improve the gain of SiP package components; Hundreds of thousands of SiP package components (including transmitting and receiving parts) ensure phase consistency under the same temperature conditions.

The thermal conductivity of the LTCC material itself is low, only 3W/(m·K). Therefore, dissipating heat under the LTCC microfluidic platform needs to face the problem of how the heat of the power chip is conducted to the microfluidic structure. LTCC substrate manufacturing and performance control are complicated by many influencing factors. It is mainly reflected in the process of lamination and sintering, especially in the lamination stage, the microfluidic structure needs to be fully protected to avoid it being fractured and resulting in structural damage or fracture of the entire substrate. For large-area, multi-layer LTCC substrates, the consistency of sintering shrinkage has a great impact on its yield and product performance. 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 that affect the sintering shrinkage. The main factors affecting the sintering shrinkage are the particle size of the powder, the proportion of the casting binder, the pressure of the hot-pressed lamination and the sintering curve, etc. .

The damage to the flatness of the LTCC substrate will adversely affect other performances of the entire substrate (such as sensors, RF signal transceivers), and also affect the reliability of the entire monolithic system. Although LTCC has many advantages, nothing is perfect and LTCC also has some disadvantages:

One is to control the shrinkage rate. Shrinkage control is one of the most important factors affecting the reliability of LTCC embedded devices. For large-area, multi-layer LTCC substrates, the consistency of sintering shrinkage has a great impact on its yield and product performance. The sintering shrinkage of the substrate is mainly controlled by controlling various factors that affect the sintering shrinkage. The main factors affecting the sintering shrinkage are the particle size of the powder, the proportion of the casting binder, the pressure of the hot-pressed lamination and the sintering curve, etc. . When the multi-layer LTCC is sintered, the shrinkage rate of the green ceramic tape in the horizontal X and Y directions is generally 12.2% to 16%, and the error is about 0.2%. The shrinkage in the thickness Z direction is typically about 15.3% to 25%, with a shrinkage error of about 0.5%. The width and spacing of the metal wiring are very small, which can be as small as tens of microns. There should not be excessive dislocation and deformation between the layers during sintering, otherwise the conductive gold wires may not be aligned and connected, resulting in circuit breakage. Or short circuit, seriously affect the performance of the module, and even make the module lose its function. In order to control the shrinkage rate, there are mainly several process methods at present: self-constrained sintering (SCS), pressure-assisted sintering (PAS), pressure-free assisted sintering (PLAS), and composite plate co-pressing. The second is the problem of chamber collapse. There are many cavities on the surface and inside of the LTCC substrate for burying components. During the lamination, lamination, and sintering process, the cavities may collapse, causing damage to the components. The flatness of the LTCC substrate will also be damaged, affecting other performances of the module, such as the accuracy of the sensor and the performance of RF transceivers. For the heat dissipation of the LTCC substrate micro-channel, the size of the internal channel is relatively large, which is more prone to collapse, and even the substrate is partially broken. also decreased. Fourth, when the absolute area of the substrate is large, the number of external leads on the substrate per unit area is large due to the large number of I/Os and high assembly efficiency. Quantity puzzle. Check and adjust the opening speed and time in the degumming stage, the opening speed and time in the closing stage, and the parameters of the safety engineering B in the closing stage. The structure of the LTCC substrate is also a key factor determining the sintering warpage of the LTCC substrate. When there are various cavity structures on the LTCC substrate, the structure is difficult to be balanced and symmetrical. These are difficult to distribute evenly, which can easily lead to excessive warpage.

The blind cavity on the surface of the substrate is usually protected by the method of inserts. The inserts are filled in the chamber during the lamination stage and taken out after sintering; however, for the chambers and microchannels inside the substrate, the inserts cannot be sintered. In this case, the sacrificial layer method is generally used, and the filled sacrificial layer will be decomposed into gas and discharged during the sintering process. The third is the problem of mechanical strength. LTCC is a brittle material with low tensile strength and flexural strength, easy to break under force, and poor mechanical strength. When the local temperature is too high, the deflection of the substrate increases during thermal deformation, which affects the integrity of the substrate and deteriorates the performance of the module. Therefore, it is necessary to consider the thermal deformation of the LTCC substrate in the thermal design stage. Metal has the advantages of high strength, good toughness, good thermal conductivity and electrical conductivity, but poor high temperature corrosion resistance. Ceramic materials have the characteristics of high temperature resistance and corrosion resistance, but they are brittle. Due to the different expansion coefficients of the two interfaces, a large thermal stress is often generated during bonding, causing peeling, peeling and reduction of heat resistance, resulting in material of destruction.

With the development of miniaturization, high performance and multi-functionalization of electronic products, the packaging density is continuously improved, and the power consumption per unit area continues to increase, resulting in higher and higher temperature of the package body. Excessive temperature not only reduces the working performance of the chip, burns the device, and breaks the connection, but also causes the package structure to break and the chip to fall off due to the excessive temperature difference. In actual research, it was found that the micro-channel based on LTCC substrate did not achieve the heat dissipation effect of metal or alloy micro-channel. This is because the thermal conductivity of LTCC is very low, only 2 ~ 5W/m·K, which causes the chip shell and the current to flow. The conduction thermal resistance between the solid coupling surfaces is large, and the heat cannot be carried away by the liquid. Traditional LTCC ceramic-metal composites have a mismatch of physical properties at the two-phase interface. Due to the difference in thermal expansion coefficients between ceramics and metals in the composites, in service environments, especially at extremely high temperatures, due to the difference between the two interfaces. Different expansion coefficients tend to have large thermal stress during bonding, causing puncture, peeling, and reduction in performance, resulting in material damage. Therefore, under the action of temperature load, stress concentration between layers is easy to occur and delamination occurs, or cracks are initiated on the interface to weaken the performance of the material, resulting in residual stress. Cause material damage, so heat dissipation has become the core problem restricting chip packaging. For a variety of severe and harsh use environments, a new type of functional material - graded functional material FGM came into being. FGM requires that the elements (composition, structure, etc.) constituting the material change continuously in the collection space, so as to obtain a non-homogeneous material whose properties change continuously in the geometric space. Functional gradient material (FGM) is a kind of non-ferrous material whose composition, structure, porosity and other elements show continuous gradient change or step change in a certain direction and structure of the material, so that the properties and functions of the material also show continuous change or step change. Homogeneous composite material. This kind of non-uniform composite material can integrate the different properties of each group of raw materials, and has the function of resistance and slow release of force.

The deformation of the multi-layer micro-channel cavity of the LTCC substrate is inevitable after the two processes of high-pressure isostatic pressing and co-firing in the manufacturing process. This is mainly because the isostatic lamination process of the new LTCC multi-layer substrate is generally pressurized at about 21MPa and 70 ℃ water temperature for 9 minutes, so that the new LTCC multi-layer substrate is hot-pressed to form a laminated substrate, resulting in the characteristic temperature of the new LTCC substrate material. The curve mismatch co-firing produces cavity deformation and cavity dislocation morphology junction. The cavity dislocation is mainly caused by the residual thermal stress generated during the co-firing process and the thermal stress and strain generated during the post-firing process. Due to the screen printing of the printing machine, the particle size of the carbon black is required to reach the micron level, so the large particle carbon black needs to be ball-milled in the actual processing process, but there is still diffusion during the printing process, because the arrangement under each chip is The cooling liquid in the flow channel is the inlet near the main channel. When it reaches the middle position, the fluid has absorbed a lot of heat and is heated. The increase of the fluid temperature will increase the convective heat transfer thermal resistance and reduce the convective heat transfer coefficient. .

SUMMARY OF THE INVENTION

The purpose of the present invention is to address the deficiencies of the prior art, in order to meet the demand for rapid and efficient thermal management and control of a certain SiP high-density three-dimensional integrated power module with a sharp increase in heat flux density as soon as possible, to provide a uniform heat dissipation, high convective heat exchange efficiency, The thermal management-controlled micro-channel LTCC-M package substrate micro-channel structure and its manufacturing process, which can effectively improve the heat dissipation capability, reduce the thermal resistance of the heat-dissipating channel, and can significantly improve the LTCC substrate micro-channel resistance to bending and mechanical impact.

The above object of the present invention can be achieved by the following technical solutions: a heat management control micro-channel LTCC-M package substrate, comprising: a heat source 4 arranged on the surface of the LTCC/metal composite substrate 1, a metal layer 3 and a heat source 4 The inlet and outlet on both sides, the water pump flow channel 2 of the said inlet and the outlet is communicated, and the inlet and the outlet are vertically communicated downward and form the micro-channel topology of the bidirectional vertical parallel circulation micro-channel with the water pump pipeline, and it is characterized in that: The LTCC substrate of the metal layer 3 below the heat source 4 is provided with a chip heat transfer channel 5 with an embedded chip, and a heat transfer channel 8 is provided below the chip heat transfer channel 5 with a bidirectional parallel multi-layer micro-channel 8. In the direction of the channel, there is a multi-layer micro-channel unit 8 in which the metal layer 3 heat exchange channels are combined into an integrated horizontal convection heat exchange and linearly parallel and juxtaposed in the blind cavity of the metal structure. Layer 6 and an array of thermally conductive metal micropillars 7 embedded in the cavity of the LTCC ceramic layer 9, thereby forming a metal layer 3 through the heat exchange channel FGM material interface isolation layer 6 Gradient heat exchange function Interface-array metal micropillars 7-multiple Layer micro-channel unit 8-LTCC ceramic layer 9 ceramic interface-layer-layer interconnection, heat management and control unit for convective heat exchange at the thermal interface of liquid cooling channel and heat transfer channel, and convective heat exchange at the thermal interface of liquid cooling channel and heat transfer channel Thermal management unit.

A process method for manufacturing a thermal management control micro-channel LTCC-M package substrate, the process method is carried out in terms of thermal expansion coefficient, elastic modulus, and thermal conductivity matching after green ceramic casting, perforation, and lamination. Material selection, interface matching structure design from thickness, size, layout parameters, FGM functional layer design from the pressure, speed, metal layer spraying temperature, and speed process parameters of printing FGM, and then according to the physical parameters of the material and the distribution of gradient components The function calculates the temperature distribution and thermal stress, and obtains the component combination system and gradient distribution whose stress intensity ratio reaches the minimum value. By printing the FGM material on the surface layer of the LTCC substrate, after the curing process, the curing of the FGM functional layer is completed, and then the FGM The surface is coated with metal metal material. After coating, the LTCC substrate is sintered together to form a metal-FGM-ceramic interface; the LTCC material of the Ferro A6M system is used as the radio frequency functional layer multilayer substrate medium. The metal-embedded microstructure ceramic-metal interface integration process and the microchannel forming process realize the integrated manufacturing of multi-layer microchannels with embedded metal microstructures on the LTCC substrate; the high-precision alignment between the layers of the LTCC substrate is realized by the filmless process. At the ceramic-metal interface, CuMoCu with a thermal expansion coefficient similar to that of LTCC ceramics is selected as the metal layer of the LTCC substrate, and the interface bonding is realized through the intermediate layer-gradient functional interface layer and the LTCC ceramic layer with a thermal expansion coefficient similar to the metal layer and LTCC. The sintering temperature is greater than 850℃, the gradient functional interface layer material co-fired with the metal layer, the LTCC substrate and the LTCC ceramic layer, so that the LTCC LTCC ceramic layer and the metal layer are closely combined under the action of the gradient functional interface layer, and the multi-layer microchannel cavity of the LTCC substrate is In the manufacturing process, after two processes of high pressure, isostatic pressing and co-firing, pressurize for at least 10 minutes at a water temperature of more than 21MPa and 70°C, so that the LTCC multilayer substrate is hot-pressed to form a laminated substrate; at 600-850°C Under the support of the three-dimensional structure of the cavity, carbon black paste, a sacrificial material with a particle size of microns, is used to make a graphic mask that meets the requirements of the screen printing scheme of the printing machine, and the filling material is filled into the cavity for several times. After printing and drying to the required filling height, sintering is performed, and the large particles of carbon black are ball-milled to control the defects of the carbon-based sacrificial material embedded cavity. After the treatment, the post-burning process is carried out.

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

In the present invention, in the direction of the heat channel between the chip and the bidirectional parallel circulation microchannel on the low temperature co-fired multilayer ceramic (LTCC) substrate, the metal layer 3 of the convective heat exchange channel, the horizontal convective heat exchange and the straight parallel juxtaposition are arranged in the direction of the heat channel. The diffusion between the multi-layer micro-channel unit 8 in the blind cavity of the metal structure and the metal-gradient functional interface material FGM-contrast material embedded in the metal micro-pillar array to the ceramic interface LTCC ceramic layer 4 ensures the continuity between the layers , using functionally graded materials (FGM) to achieve different functions on both sides of the material, while overcoming the defect of mismatched properties of different material binding sites. Since the composition and properties of FGM are very different from those of traditional materials, the thermal and mechanical properties continuously change in a certain direction and the diversity of functions, compared with the traditional LTCC substrate microchannel, it is proved that the area of heat transfer to the fluid can be increased. , which can effectively improve the heat dissipation capacity and heat dissipation uniformity, and improve the convective heat exchange efficiency. Utilizing FGM has excellent metal-substrate interface compatibility and high flexibility, reliability and gradient functionality, it can prevent the generation of micro-cracks, eliminate spalling, and prevent it from being fractured to cause structural damage or the entire substrate. . Horizontal convection heat exchange and the multi-layer micro-channel unit 8 in the blind cavity of the metal structure and the metal-gradient functional interface material FGM-ceramic interface LTCC ceramic layer embedded in the metal micro-pillar array can avoid the micro-channel tube The wall has defects such as roughness, collapse, blockage, substrate warpage, and high stress. High-density thermal conductive vias are fabricated in the microfluidic channel through the LTCC underlying substrate, and the designed heat dissipation structure can effectively improve the heat dissipation of the heat source area under the LTCC microfluidic platform. The problem of how the heat of the power chip is conducted to the microfluidic structure is faced. , the temperature value will gradually decrease with the increase of the load cooling flow. At the same time, it solves the defects of roughness, collapse, blockage, substrate warpage, and high stress on the microchannel wall after the number of microchannel layers in the LTCC substrate is increased. At the same time, it ensures the phase consistency of hundreds of SiP package components under the same temperature conditions. The heat conduction is carried out by flowing through the thermally conductive micro-pillars embedded in the LTCC substrate and under the heating chip, and the heat is dissipated through the external heat exchange system, which improves the convective heat transfer coefficient. Thermal diffusion of LTCC dissipates heat.

In order to meet the demand for rapid and efficient thermal management and control due to the sharp increase in heat flux density of a SiP high-density three-dimensional integrated power module, the invention adopts the LTCC substrate embedded metal microstructure multi-layer microchannel structure and the LTCC substrate metal micropillar array and gradient functional interface layer Layer interconnection to form a new thermal interface of chip-metal layer-gradient functional interface layer-embedded array micropillars-heat transfer channel of liquid cooling channel and chip-, which can increase the area of heat exchange with fluid, the array and cavity And the gradient functional interface layer is interconnected to form a heat transfer channel of chip-metal layer-gradient functional interface layer-embedded array micro-pillars-liquid cooling flow channel, so as to achieve the purpose of effective thermal management and control. Moreover, the application of metal layer and gradient functional interface layer can significantly improve the resistance of LTCC substrate microchannels to bending and mechanical impact. Since the LTCC substrate is embedded with a metal layer and a gradient functional interface layer on the heat transfer path of the chip, the ability of the LTCC substrate microchannel to resist bending and mechanical shock is significantly improved. Embedded metal microstructures and multi-layer microchannels with efficient heat transfer can ensure stable thermal management of more than 900 SiP package components.

The invention designs the metal layer, the gradient functional interface layer and the LTCC ceramic layer embedded with the metal micro-pillar array in the direction of the thermal channel between the LTCC substrate chip and the micro-flow channel. Among them, the gradient functional interface material (FGM) not only solves the interface stress problem of the composite material, but also maintains the composite properties of the material. On the other hand, FGM does not produce abrupt changes at the interface by gradually changing the volume fraction of material components. FGM can operate under extremely high temperature gradients and maintain the structural integrity of its components, reducing thermal stress, residual stress and stress concentration factor, thereby eliminating interface problems and flattening stress distribution. Therefore, metal/ceramic FGM can not only give full play to the good high temperature resistance and corrosion resistance of ceramics and the high strength and toughness of metals, but also solve the problem of mismatching thermal expansion coefficients between metals and ceramics. The heat generated by the chip can be quickly and efficiently transferred to the liquid cooling channel through metal layers and the like. The thermal resistance of the heat dissipation channel is reduced to achieve the purpose of effective thermal management. Moreover, the application of metal layer and gradient functional interface layer can significantly improve the resistance of LTCC substrate microchannels to bending and mechanical impact.

Aiming at the difficulty of the key process of the micro-channel of the LTCC substrate, the present invention is based on the structure of the micro-channel heat dissipation exchange system, combined with the limitations of the LTCC process level, from the heat source to the arrangement and distribution of the multi-layer micro-channel metal through holes, the multi-layer micro-channel structure and its structure. The structure of the runner cavity, fluid flow velocity, runner pressure, and shape deformation were simulated by simulating the structure of the heat source to the hot channel runner, and the structure size distribution of the thermally conductive micropillars and runner cavity was obtained. Through the integrated manufacturing technology approach of multi-layer micro-channel LTCC embedded with metal microstructure, it mainly solves the problems of interlayer alignment of multi-layer LTCC substrate, integrated manufacturing of ceramic-metal interface with embedded metal micro-structure, and multi-layer micro-channel forming of LTCC substrate, etc. technical challenge. Through the embedded chip in the LTCC substrate-metal layer convection heat exchange-FGM-LTCC ceramic layer gradient functional interface layer-embedded micro-pillar array-liquid cooling channel heat transfer channel and chip thermal interface process design, LTCC substrate embedded The breakthroughs in key technologies such as the integrated manufacturing process of metal microstructure multilayer microchannels and the defect control of metal microstructure multilayer microchannels embedded in LTCC substrates have avoided the existence of physical properties at the two-phase interface of traditional LTCC ceramic-metal composites. performance mismatch. By integrating the microfluidic heat dissipation channel inside the LTCC substrate, especially under the high-power devices assembled on the LTCC substrate, the heat dissipation characteristics of the LTCC substrate can be effectively improved. Combined with high-density thermal via technology and micro-channel fabrication technology, the fabrication of high-density thermal vias with a local hole ratio of up to 50% is achieved. The test results confirmed that the LTCC microfluidic system has a heat dissipation capacity of not less than 50W/c㎡. It can improve the application range of LTCC substrates in microwave power components and LTCC-SIP technology. The LTCC substrate micro-channel structure, embedded metal micro-structure and multi-layer micro-channel with efficient heat transfer can ensure the stable thermal management capability of more than 900 SiP package components. And compared with the traditional heat dissipation method, a good heat dissipation effect has been achieved.

The present invention considers the LTCC/metal composite substrate as a whole, and aims at the micro-channel structure of the LTCC substrate, respectively from the key process of embedded metal microstructure ceramic-metal, the key process of integrated manufacturing and the key process of defect control, and the metal layer has higher thermal conductivity. High efficiency, better mechanical strength and thermal expansion coefficient similar to LTCC, play the role of heat dissipation and reinforcement. Although it is difficult to directly combine LTCC ceramics and metal layers with respect to ceramic-metal interface construction, the present invention is achieved through an intermediate layer-gradient functional interface layer. The gradient functional interface layer can achieve good interface bonding 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 (sintering temperature about 850°C), gradually changing the composition or structure in a continuous, step-by-step manner, changing the properties of the composite, creating a continuous The gradient of embedded metal microstructures realizes the integrated fabrication of ceramic-metal interface gradients. FGM has a similar thermal expansion coefficient with the metal layer and LTCC substrate. After sintering, it has high chemical stability, thermal stability, mechanical strength, etc., which can make the LTCC ceramic layer and the metal layer close under the action of the gradient functional interface layer. Combined, reduce ceramic-metal heat transfer thermal resistance and improve reliability. 3D structural support during lamination and sintering; sacrificial material matched to the LTCC substrate TCE without stressing the cavity during sintering; easy removal (by decomposition or other means) after sintering. One is to reduce the residual stress generated in the co-firing process, and the other is to reduce the thermal stress in the post-firing process.

The high-precision alignment between the layers of the LTCC substrate of the present invention is realized by a filmless process, because the filmless process can release more stress, thereby improving the interlayer alignment accuracy. The production process is one-time sintering and molding, and the printing accuracy is high, which can meet the requirements of high current and high temperature resistance, and has excellent thermal conductivity than ordinary PCB circuit substrates. Better temperature characteristics, such as smaller coefficient of thermal expansion (CTE), smaller resonant frequency temperature coefficient.

In the present invention, the substrate of the microcircuit or the component is used as the carrier of the package, and the 1/0 terminal of the package is directly drawn out on the substrate and connected with other parts of the package body, so that the substrate and the shell are integrated into a package, which can better solve the problem of high density Packaging challenges for integrating complex MCM-Cs.

Description of drawings

In order to illustrate the technical solutions in this embodiment more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiment. Obviously, the accompanying drawings in the following description are only some embodiments of this embodiment. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

FIG. 1 is a schematic diagram of the thermal management control micro-channel LTCC package substrate of the present invention.

2 is a schematic diagram of an optional embodiment of the structure size and distribution of the embedded array of thermally conductive metal micropillars in FIG. 1;

FIG. 3 is a process flow diagram of manufacturing a thermal management micro-channel LTCC-M package substrate;

In the picture: 1. LTCC-M package substrate, 2. Water pump flow channel, 3. Metal layer, 4. Heat source, 5. Chip heat transfer channel, 6. FGM material interface isolation layer, 7. Array of thermally conductive metal micropillars, 8. Multilayer microfluidic unit, 9.LTCC ceramic layer.

The technical solution of this embodiment will be described in detail below through the accompanying drawings and specific embodiments.

Detailed ways

See Figure 1. In the preferred embodiment described below, a heat management micro-channel LTCC-M package substrate includes: a heat source 4 disposed on a surface of the LTCC/metal composite substrate 1, a metal layer 3, and inlets and outlets on both sides of the heat source 4 , the water pump channel 2 that communicates with the inlet and the outlet, vertically connects the inlet and the outlet downward and forms a bidirectional vertical parallel circulation microchannel topology structure with the water pump pipeline, it is characterized in that: the metal below the heat source 4 The LTCC substrate of layer 3 is provided with a chip heat transfer channel 5 with embedded chips, and in the direction of the heat channel between the bidirectional parallel multi-layer micro-channels 8 under the chip heat transfer channel 5, set There is a multi-layer micro-channel unit 8 in which the heat exchange channel of the metal layer 3 is combined into an integrated horizontal convection heat exchange and parallel in a straight line in the blind cavity of the metal structure. Array of thermally conductive metal micropillars 7 in the cavity of LTCC ceramic layer 9, thus forming metal layer 3 Heat exchange channel through heat exchange channel FGM material interface isolation layer 6 Gradient heat exchange function Interface-array metal micropillars 7-multilayer Micro-channel unit 8-LTCC ceramic layer 9 Ceramic interface-layer-by-layer interconnection, heat management and control unit for convective heat transfer at the thermal interface of liquid cooling channel and heat transfer channel control unit.

The heat generated by the heat source 4 is transferred, and the passive components and metallized wirings and through-hole metallized chips and laminations partially integrated in the cavity of the metal layer 3 are filled with the "FGM insert" in the LTCC blind cavity manufacturing. The thermal chip thermal load on the upper surface of the substrate is used to simulate the heat source that needs to be dissipated, fuse with each other through diffusion on the molecular scale to form a seamless object and the rheological properties of the continuously graded cellulose-based material to distribute stress at the interface, using high contrast and The multi-dimensional stiffness gradient obtains the heat flux density gradient information of the multi-layer micro-channel unit 8; the cooling fluid flows in from the inlet, passes through the main channel at the branch outlet of the parallel branch channel along the path, and flows out from the outlet.

In the convective heat exchange, the heat dissipation of the heating chip and the LTCC is carried out by flowing through the array of thermally conductive metal micropillars 7 embedded under the FGM material interface isolation layer 6, and the heat generated by the chip passes through the metal micropillars 7. Layer 3 convective heat exchange rapid cooling and the multi-layer micro-channel units 8 in the blind cavity below the array of thermally conductive metal micro-pillars 7 are quickly and efficiently transferred to the liquid cooling channel, and the heat is dissipated through the external heat exchange system.

In an optional embodiment, heat exchange channels with metal microstructures are formed in the broadside direction of the metal layer 3 , and the heat exchange channels are arrayed in parallel along the broadside direction of the metal layer 3 . As shown in FIG. 2 , the array of thermally conductive metal micro-pillars 7 of the LTCC ceramic layer 9 can be made of gold paste, and the parameters and distribution can be designed in a matrix arrangement with equidistant pitches, or with b as the side and c as the waist. Isosceles triangles, and dotted arrays arranged in a 45-degree cross-arrangement matrix, and dotted linear arrays are spaced to form dotted isosceles triangles staggered and distributed in dotted arrays.

In the calculation of temperature distribution and thermal stress, the conditions for the one-to-one correspondence between the moment generating function M(s) of random variables and the distribution function are firstly given, and then the independent discrete and continuous random The distribution of linear operation, division and product of variables, the coefficient value is brought into the discrete distribution function, converted into discrete accumulation function and continuous accumulation function, and then differentiated to obtain density functions, and their distribution functions and probability density functions are derived. The moment generating function of the sum of a random number of mutually independent random variables, the corresponding distribution function F(x)=P{X≤x} can be obtained by inverting the moment generating function. 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, then X is said to obey the order of p is a 0-1 distribution of the parameters. Suppose all possible values of 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,..., where λ>0 is a constant, then X is said to obey the Poisson distribution with parameter λ, denoted as X～π(λ).

According to the current processing technology and the influence of micro-cavity on the performance of the substrate, in order to avoid the design and processing of the multi-layer micro-channel structure that causes the collapse of the substrate surface, the LTCC substrate is designed according to the new LTCC substrate opening process and temperature gradient distribution, and the heat source chip is placed on the substrate. On the upper surface, four layers of green ceramic sheets are reserved on the surface of the substrate, which are sintered with 25 layers of green ceramic sheets. Among them, 1-4 layers of green ceramic sheets are solid layers, mainly burying some passive devices and active devices. 5- 17 is the runner layer, 18-25 are the inlet and outlet adjustment layers, after the LTCC substrate is sintered, the LTCC size: length and width (WL) ≥ 60mm, thickness (H) ≥ 8mm, and the thickness of each layer of the runner layer is ≥ 200um.

Micro-channel structure Using ANSYS software to analyze the single-layer micro-channels of six common structures of straight-inserted micro-channel, Archimedes rectangular spiral micro-channel, snake-shaped curve micro-channel, H-shaped and tree-shaped micro-channel. The flow channel is modeled and simulated, and the LTCC multi-layer microchannel cross-sectional structure is prefabricated according to the substrate temperature distribution, velocity distribution and pressure distribution of the fluid in the flow channel under different chip powers. Micro-channel structure; snake-shaped curve single-layer micro-channel structure; according to the three-dimensional distribution of the heat flux density of the heat source, the finite element simulation method is used for the three common structures of in-line micro-channel, spiral type and snake-curve type. The coupling method is used to simulate and calculate the microchannel structure under the thermal fatigue state. The structure is subjected to flow-heat coupling and stress-strain state. According to the combination of different single-layer microchannels and multi-layer interconnections, the liquid flow rate and chip power of the multi-layer microchannel cavity are obtained. According to the change rule, one of the in-line microchannel, spiral type and snake curve type is selected as the microchannel structure.

In order to reduce the production cost and improve the product quality and efficiency, the present invention aims at the key process problems in the LTCC process. In the process of manufacturing the thermal management and control micro-channel LTCC-M package substrate, an infrared laser with a wavelength of 964 nm is used in the metal layer 3 and the FGM. The material interface isolation layer 6 is punched, and the grooves in parallel arrays along the broad side are cut in the metal layer 3. The laser and mechanical combined processing method is used. First, the water pump flow on both sides of the LTCC/metal composite substrate 1 is punched by a laser cutting machine. Pass 2: Roughly cut multi-layer microchannels on the green ceramic tape, and then use a CNC milling cutter to finish the channels into a multi-layered microchannel structure that meets the requirements of smooth fluid flow, and use a self-propagating high-temperature synthesis method to form FGM compounds The element powder and metal powder are filled according to the gradient composition, statically formed, put into the reaction vessel, ignited and burned at one end, and propagated in the reverse direction, forming a molten pool on the surface of the substrate, and synthesizing a composition gradient or grain size gradient along the cross section. The layered structure generates intermetallic compound gradient functional materials, and the strengthening phase is prepared in a gradient distribution, which is composed of the reaction products and the FGM of the metal functional materials.

See Figure 3. According to the present invention, after the LTCC green ceramics are casted, punched, and laminated to form a three-dimensional structure through processes such as casting to generate green ceramic tapes and co-firing, the materials are matched in terms of thermal expansion coefficient, elastic modulus, and thermal conductivity. Selection, interface matching structure design from thickness, size, layout parameters, FGM functional layer design from the pressure, speed, metal layer spraying temperature, speed process parameters of printing FGM, through the material printing of FGM on the surface of the LTCC substrate, based on The combination of the polymer's manufacturing materials promotes the diffusion of molecules on the filament boundary and generates a continuous gradient, creating a multi-dimensional and continuous stiffness gradient. Multi-layer green ceramic layer, after sintering, the relationship between sintering shrinkage rate and hot pressing temperature and pressure was measured; after the curing of the FGM functional layer was completed, metal metal material was coated on the surface of the FGM. After coating, the LTCC substrate was sintered together. Forming a metal-FGM-ceramic interface; using Ferro A6M system LTCC material as the RF functional layer multilayer substrate medium, through the LTCC multilayer fabrication process, the embedded metal microstructure metal-ceramic interface integration process, and the micro-channel forming process to achieve Integrated fabrication of multi-layer micro-channels with embedded metal microstructures on LTCC substrates; high-precision alignment between layers of LTCC substrates is achieved by means of a filmless process, and a metal-ceramic interface is constructed. LTCC substrate, through the intermediate layer-FGM gradient functional interface layer and metal layer, LTCC ceramic layer with similar thermal expansion coefficient to achieve interface bonding, sintering stage using sintering temperature 750 ℃ -850 ℃, 20-25Mpa pressure, and metal layer, LTCC The metal layer composite substrate and the LTCC ceramic layer are co-fired to produce crystallization and devitrification reactions. By optimizing the sintering curve, the airflow rate at each stage is optimized, the stress due to the mismatch of thermal expansion coefficients of different materials is relieved, and the heating rate and time of the stage are adjusted. Important process parameters such as time, air flow at each stage, etc., make the LTCC ceramic layer and the metal layer closely combine under the action of the gradient functional interface layer of the gradient functional interface layer material FGM. In the manufacturing process, after two processes of high pressure, isostatic pressing lamination and co-firing, the LTCC multi-layer substrate is hot-pressed to form a laminated substrate under pressure greater than 21MPa and a water temperature of 70°C for at least 9 minutes.

Under the three-dimensional structural support of the cavity of the LTCC metal layer composite substrate at 600-800 °C, carbon black paste, a sacrificial material with a particle size of microns, is used to produce a graphic mask that meets the requirements of the screen printing scheme of the printer. , Filling the cavity with filling material, sintering after printing and drying to the required filling height, ball-milling large particles of carbon black, controlling the defects of the carbon-based sacrificial material embedded cavity, and post-firing the co-fired substrate An annealing treatment step is added before, and after the substrate is annealed, a post-firing process and lamination are performed.

It should be understood that this embodiment and the specific features in the embodiment are a detailed description of the technical solution in this embodiment, rather than a limitation on the technical solution in this embodiment. can be combined with each other.

Claims (10)

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.

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