An embedded microchannel ltcc substrate with added microneedle fins

Abstract

The application discloses an embedded manifold microchannel LTCC substrate with added micro needle fins, which comprises a top cover layer, a middle microchannel layer, a bottom substrate layer and an external driving assembly. The top cover layer is provided with a radio frequency device unit. The middle microchannel layer is provided with a main path and a bypass manifold microchannel. A plurality of shunt micro needle fins are arranged at the input section of the main path manifold microchannel. A plurality of turbulence micro needle fins are arranged at the bypass manifold microchannel. The bottom substrate layer is provided with an inlet / outlet port. The external driving assembly comprises a controller, a micro tube and a micro pump. During operation, the cooling medium is transmitted through the micro tube, flows through the main path manifold microchannel of the middle microchannel layer, is distributed to the bypass manifold microchannel through the shunt micro needle fins, is fully mixed under the action of the turbulence micro needle fins, carries away the heat generated by the high-power radio frequency device and is transported to the external environment. The application realizes the organic fusion of the LTCC substrate and the heat dissipation technology and strengthens the efficient cooling of the high heat flux density radio frequency device.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of heat dissipation technology, and particularly relates to a micro-needle fin added embedded manifold micro-channel LTCC substrate. BACKGROUND

[0002] Low Temperature Co-fired Ceramic (LTCC) packaging can integrate multiple chips and other components into the same package to achieve system functionality, which is an important means to realize the integration, multi-function and light weight of radio frequency microsystems. LTCC substrate can realize the application requirements of high frequency, low loss and high speed transmission of radio frequency microsystems due to its excellent high frequency performance. However, the thermal conductivity of the LTCC substrate is poor (< 20 W / (m·k)), which causes the heat generated by the integrated power device to be unable to dissipate in time, becoming a bottleneck problem limiting the application of LTCC in high-power microwave components and multi-functional microsystems. At present, forced air cooling or liquid cooling is mainly used to solve the problem of heat dissipation of LTCC substrate. However, forced air cooling has gradually failed to meet the thermal management requirements of device heat dissipation capacity and size; forced liquid cooling mainly uses liquid cooling structure outside the tube shell to solve the heat dissipation problem, but the thermal control components are complex, the cost is high, and the reliability is low. The emergence of embedded heat dissipation provides a new solution for heat dissipation. It has excellent heat dissipation performance, is easy to integrate, and can quickly and efficiently remove the heat generated by the heating module, but there are many problems such as single micro-channel topology, insufficient heat dissipation capacity, poor temperature consistency, and complex process in the heat management of radio frequency devices using embedded liquid cooling heat dissipation technology. SUMMARY

[0003] The present application provides a micro-needle fin added embedded manifold micro-channel LTCC substrate, which is embedded in the LTCC substrate by one-body laminated sintering process, and the rhombic micro-needle fin is added in the manifold micro-channel to enhance the heat dissipation capacity and improve the temperature consistency.

[0004] The technical solution of the present application is as follows: a micro-needle fin added embedded manifold micro-channel LTCC substrate, comprising: a top cover plate layer, a middle micro-channel layer, a bottom substrate layer, and an external driving component.

[0005] The top cover plate layer is formed by laminated sintering of first to fifth green sheets, and the radio frequency device unit is arranged on the top cover plate layer, and the heat conduction column is embedded between the top cover plate layers. The heat conduction column is made of copper, which can help the heat generated by the radio frequency device unit to be quickly transferred to the middle micro-channel layer.

[0006] The middle micro-channel layer is formed by sintering together the sixth to ninth green ceramic sheets, and the main channel micro-channel and the bypass channel micro-channel are arranged in the middle micro-channel layer, a plurality of single-row shunt micro-fin are arranged on the main channel micro-channel, and a plurality of multi-row staggered disturbance micro-fin are arranged on the bypass channel micro-channel.

[0007] The bottom substrate layer is formed by sintering together the tenth to fifteenth green ceramic sheets, and the liquid inlet and the liquid outlet are arranged on the bottom substrate layer.

[0008] The external driving assembly comprises a controller, a liquid inlet micro-pipe, a liquid outlet micro-pipe and a micro-pump.

[0009] During operation, the cooling medium is transmitted to the liquid inlet through the liquid inlet micro-pipe by the micro-pump under the control of the controller, flows through the main channel micro-channel of the middle micro-channel layer, is distributed to the bypass channel micro-channel by the shunt micro-fin, is fully mixed under the action of the disturbance micro-fin to take away the heat generated by the radio frequency device unit, and finally, the cooling medium is transmitted to the liquid outlet micro-pipe through the liquid outlet and then is delivered to the external environment.

[0010] Further, the cooling medium material includes but is not limited to deionized water and fluorinated liquid with insulation performance.

[0011] Further, the main channel micro-channel of the middle micro-channel layer has a center-symmetrical regular hexagonal flow channel structure.

[0012] Further, the main channel micro-channel and the bypass channel micro-channel of the middle micro-channel layer are arranged in the area directly below the radio frequency device unit of the top cover layer.

[0013] Further, one main channel micro-channel and a plurality of bypass channel micro-channels are arranged in the middle micro-channel layer.

[0014] Further, the flow channel height of the main channel micro-channel is consistent and is about 400 μm, and the spacing of the adjacent bypass channel micro-channels is consistent and is about 500 μm.

[0015] Further, the cross-sectional shape of the shunt micro-fin and the disturbance micro-fin is a rhombus with an acute angle of 60° and the circumferences are consistent.

[0016] Further, the shunt micro-fin is arranged in the input section of the main channel micro-channel, and the disturbance micro-fin is arranged in the entire flow path of the bypass channel micro-channel.

[0017] Further, the main channel micro-channel has a trapezoidal structure, the input section has a gradually narrowing trapezoidal shape and is connected to the liquid inlet, and the output section has a gradually widening trapezoidal shape and is connected to the liquid outlet.

[0018] Further, the cooling medium flowing through the main channel manifold input section is evenly distributed to several bypass channel manifolds through the distribution micro-needle fins, then fully mixed through the distribution micro-needle fins in the bypass channel manifolds, and finally flows from the outlet to the output section of the main channel manifold and out.

[0019] Further, the inlet and outlet ports are sealed by fasteners and sealant.

[0020] Further, the controller is powered by DC 3.7 V, and the default working frequency after starting the circuit is 30 Hz, the working frequency range is 1-60 Hz, and the working frequency of the controller is adjusted to control the flow of the cooling medium pumped by the micropump.

[0021] Further, the micropump is a piezoelectric micropump, and the liquid supply flow is greater than 50 ml / min, and the maximum lift is greater than 25kPa.

[0022] The cooling medium that absorbs heat is discharged from the outlet to the external environment under the driving action of the micropump, and is pumped into the inlet by the micropump after cooling, achieving the purpose of repeated heat dissipation.

[0023] Further, the cooling medium that absorbs heat is discharged from the outlet to the external environment under the driving action of the micropump, and is pumped into the inlet by the micropump after cooling, achieving the purpose of repeated heat dissipation.

[0024] Further, in order to ensure that the liquid cooling circulation microchannel does not collapse, solve the problem of not delaminating and bulging during sintering, the top cover layer, the middle microchannel layer and the bottom substrate layer of the green ceramic sheet are respectively stacked and pre-pressed during the preparation process to obtain sub-modules of the top, middle and bottom parts. Then, the sub-modules are bonded using an organic adhesive to form a whole module in a low-temperature and low-pressure manner; finally, a multilayer ceramic substrate is laminated and sintered to obtain an LTCC substrate integrated with an embedded manifold microchannel.

[0025] Further, the preparation process adds micro-needle fin manifold microchannel structures by laser cutting on the green ceramic sheet; and the manifold microchannel is filled with sacrificial materials such as graphite and starch, which can transmit pressure during lamination to support and protect the microchannel from or reduce the influence of forming pressure, and maximize the stability of the microchannel structure and size.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] (1) The LTCC substrate is embedded with microchannels, and the forced convection of the cooling medium directly cools and dissipates heat from the heat-generating elements, which can improve the heat dissipation effect of the packaged device and meet the heat dissipation needs of miniaturized products.

[0028] (2) The micro-needle fin structure plays the role of flow splitting and flow disturbance, increases the heat dissipation surface area, and effectively improves the heat exchange efficiency.

[0029] (3) The manifold micro-channel structure in the form of regular hexagon reduces the thermal resistance, reduces the temperature gradient, makes the heat more evenly distributed and dissipated, and avoids local overheating.

[0030] (4) The embedded manifold micro-channel design does not occupy the external space of the ceramic substrate, reduces the space occupancy rate of the product, makes the size of the entire system smaller and more lightweight, and is suitable for lightweight and small-sized applications. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 A cross-sectional view of an embedded manifold micro-channel LTCC substrate with added micro-needle fins is provided for some embodiments of the present application;

[0032] Figure 2 A flow channel diagram of an embedded manifold micro-channel LTCC substrate with added micro-needle fins is provided for some embodiments of the present application;

[0033] Figure 3 A work flow diagram of an embedded manifold micro-channel LTCC substrate with added micro-needle fins is provided for some embodiments of the present application;

[0034] Figure 4 A preparation flow diagram of an embedded manifold micro-channel LTCC substrate with added micro-needle fins is provided for some embodiments of the present application.

[0035] In the figure, 1 is a top cover plate layer, 2 is a heat-conducting column, 3 is a middle micro-channel layer, 4 is a bottom substrate layer, 5 is an external driving component, 6 is a radio frequency device unit, 7 is a main path manifold micro-channel, 8 is a bypass manifold micro-channel, 9 is a flow splitting micro-needle fin, 10 is a flow disturbance micro-needle fin, 11 is a liquid inlet, 12 is a liquid outlet, 13 is a controller, 14 is an inlet micro-pipe, 15 is an outlet micro-pipe, and 16 is a micro-pump. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0037] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0038] In addition, the descriptions such as "first", "second" and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implying the number of the indicated technical features. Therefore, the features defined as "first", "second" can be explicitly or implicitly included at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly and specifically limited.

[0039] In the present application, unless otherwise explicitly specified and limited, the terms "connection", "fixing" and the like should be understood in a broad sense, for example, "fixing" can be fixed connection, or detachable connection, or integral; "connection" can be mechanical connection, or electrical connection. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] In addition, the technical solutions of various embodiments of the present application can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope required by the present application.

[0041] The specific embodiments, technical difficulties and points of the present application will be further introduced below in combination with the design examples.

[0042] In one embodiment, referring to Figure 1 and Figure 2 , a micro-needle fin embedded manifold micro-channel LTCC substrate is provided, which comprises a top cover plate layer 1, a middle micro-channel layer 3, a bottom substrate layer 4 and an external driving component 5.

[0043] The top cover plate layer 1 is formed by laminated sintering of first layer to fifth layer green sheet, and the top cover plate layer 1 comprises a radio frequency device unit 6, a heat conduction column 2.

[0044] The middle micro-channel layer 3 is formed by laminated sintering of sixth layer to ninth layer green sheet, and the middle micro-channel layer 3 comprises a main road manifold micro-channel 7, a plurality of bypass manifold micro-channels 8, a plurality of shunt micro-needle fins 9 and a plurality of turbulence micro-needle fins 10.

[0045] The bottom substrate layer 4 is formed by laminated sintering of tenth layer to fifteenth layer green sheet, and the bottom substrate layer 4 comprises a liquid inlet 11 and a liquid outlet 12.

[0046] The external driving component 5 comprises a controller 13, a liquid inlet micro-pipe 14, a liquid outlet micro-pipe 15 and a micro-pump 16.

[0047] The LTCC substrate thickness is at least 1.5 mm, that is, the total number of layers is not less than 15 layers, and then the number of green sheets of the top cover layer 1, the middle microchannel layer 3, and the bottom substrate layer 4 is not fixed, but the thickness of the middle microchannel layer 3 is not more than 1 / 3 of the total thickness, and the thickness of the top cover layer 1 and the bottom substrate layer 4 is equal.

[0048] Specifically, the controller is powered by DC 3.7 V, and the default working frequency of the starting circuit is 30 Hz. By adjusting the working frequency of the controller, the cooling medium flow rate of the micropump is controlled. Through the action of the micropump, the cooling medium is transmitted to the liquid inlet through the liquid inlet microtube, flows through the main path manifold microchannel of the middle microchannel layer, is distributed to the bypass manifold microchannel through the shunt microfin, and is fully mixed under the action of the turbulence microfin to carry away the heat generated by the radio frequency device unit. Finally, the cooling medium is transmitted to the liquid outlet through the liquid outlet microtube and then delivered to the external environment.

[0049] The cooling medium material includes but is not limited to water and fluorinated liquid with insulation performance.

[0050] In an embodiment, referring to Figure 1 , the radio frequency device unit is a prior art and generally includes connected switches, power amplifiers, limiters, and low-noise amplifiers.

[0051] In an embodiment, referring to Figure 1 , the liquid inlet and outlet are sealed by fasteners and sealant at the contact position with the liquid inlet and outlet microtubes; and the working frequency of the controller is adjusted to control the cooling medium flow rate of the micropump.

[0052] In an embodiment, referring to Figure 2 , the main path manifold microchannel and the bypass manifold microchannel of the middle microchannel layer are located in the area directly below the radio frequency device unit on the top ceramic cover layer. The manifold microchannel of the middle microchannel layer has a center-symmetric regular hexagonal flow channel structure. The main path manifold microchannel has a trapezoidal structure, and the input section is a gradually tightened trapezoidal shape connected with the liquid inlet; and the output section is a gradually expanded trapezoidal shape connected with the liquid outlet.

[0053] In an embodiment, referring to Figure 2 , the center-symmetric regular hexagonal flow channel structure includes one main path manifold microchannel and a plurality of bypass manifold microchannels, and the plurality of manifold microchannels have a regular hexagonal shape with increasing side length from the inside to the outside.

[0054] In an embodiment, referring to Figure 2The manifold microchannels have consistent height, and the adjacent bypass manifold microchannels have consistent spacing; the shunt micro-needle fin is arranged at the input section of the main channel manifold microchannel, and the spoiler micro-needle fin is arranged at the bypass manifold microchannel; the cross section shape of the micro-needle fin can be a rhombus, a triangle, a circle or a water drop shape, and the rhombus with an acute angle of 60° is adopted in consideration of the process difficulty and the heat dissipation effect.

[0055] In an embodiment, referring to Figure 3 , the external driving assembly workflow diagram, direct current power supply and open the controller start power, the circuit starts normal work, the default frequency of the initial state is 30Hz; the frequency is changed by pressing the relay button to control the pump pressure flow, and the current working state is saved by pressing the relay button for a long time, and the micropump works continuously according to the state.

[0056] In an embodiment, referring to Figure 4 , a preparation flow chart of the embedded manifold microchannel LTCC substrate with additional micro-needle fins provided by some embodiments of the application. The green sheet for making the LTCC substrate can be Dupont 951 or Dupont 940, etc., the thickness of each layer of green sheet is about 114 μm, the shrinkage rate in X and Y directions is 12.7 ± 0.3%, the shrinkage rate in Z direction is 15 ± 0.5%, and the green sheet density is 3 g / cm 3 . The thermal conductivity is 3.3 W / (m·k). First, the circuit pattern is made and the through hole for electrical interconnection is manufactured by screen printing on the green sheet; then, the positioning hole, the through hole and the heat dissipation hole are punched on the green sheet; secondly, the cavity and the microchannel structure are made by laser cutting on the multilayer green sheet; then, the microchannel is filled with sacrificial materials such as graphite and starch, which can transfer pressure during lamination to support and protect the microchannel from or reduce the influence of forming pressure, so as to maintain the stability of the microchannel structure and size to the greatest extent, and the deformation problem can be solved; the green sheets are laminated and aligned through the positioning hole; the top, middle and bottom green sheets are laminated and pre-pressed respectively to obtain the top, middle and bottom sub-modules; then the sub-modules are bonded by organic adhesive to form a whole module in low temperature and low pressure; finally, the multilayer ceramic substrate is made by lamination and sintering, and the sacrificial material is vaporized and discharged to form a microchannel cavity during the sintering process, so as to obtain the LTCC substrate integrated with embedded microchannel and heat dissipation.

[0057] Although the application has been described in detail with general description and specific embodiments above, some modifications or improvements can be made on the basis of the application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the application, all belong to the scope of protection claimed by the application.

Claims

1. An in-line manifold microchannel LTCC substrate with added microneedle fins, characterized by, The application relates to a cooling device for radio frequency (RF) devices, which comprises a top cover layer (1), a middle micro-channel layer (3), a bottom substrate layer (4) and an external driving assembly (5), a radio frequency device unit (6) is arranged on the top cover layer (1), a plurality of heat conduction columns (2) are arranged in the radio frequency device unit (6), the heat conduction columns (2) are used for conducting heat generated by the radio frequency device unit (6), the middle micro-channel layer (3) is provided with a main path manifold micro-channel (7) and a bypass manifold micro-channel (8), a plurality of shunt micro-needle fins (9) are arranged on an input section of the main path manifold micro-channel (7), a plurality of turbulence micro-needle fins (10) are arranged on the bypass manifold micro-channel (8), a liquid inlet (11) and a liquid outlet (12) are formed in the bottom substrate layer (4), and the external driving assembly (5) is composed of a controller (13), a liquid inlet micro-pipe (14), a liquid outlet micro-pipe (15) and a micro-pump (16). During operation, cooling working medium is transmitted to the liquid inlet (11) through the liquid inlet micro-pipe (14) under the regulation of the controller (13) and the action of the micro-pump (16), flows through the main path manifold micro-channel (7) of the middle micro-channel layer (3), is distributed to the bypass manifold micro-channel (8) through the shunt micro-needle fins (9), is fully mixed under the action of the turbulence micro-needle fins (10) and then carries away the heat generated by the radio frequency device unit (6), finally, the cooling working medium is transmitted to the liquid outlet micro-pipe (15) through the liquid outlet (12) and then is delivered to the external environment. The main path manifold micro-channel (7) and the bypass manifold micro-channel (8) of the middle micro-channel layer (3) are located in the area directly below the radio frequency device unit (6) arranged on the top cover layer (1). The micro-channels of the middle micro-channel layer (3) are in a center-symmetrical regular hexagonal channel structure, the channel heights of the micro-channels are consistent, and the spacing of the adjacent bypass manifold micro-channels (8) is consistent. The cross-sectional shapes of the shunt micro-needle fins (9) and the turbulence micro-needle fins (10) are all rhombuses with an acute angle of 60 degrees and consistent circumferences. The shunt micro-needle fins (9) are arranged on the input section of the main path manifold micro-channel (7), and the turbulence micro-needle fins (10) are arranged on the whole flow path of the bypass manifold micro-channel (8). The main path manifold micro-channel (7) is in a trapezoidal structure, the input section is a gradually-tightening trapezoidal shape and is connected with the liquid inlet (11), and the output section is a gradually-enlarging trapezoidal shape and is connected with the liquid outlet (12). The LTCC substrate is formed by laminating and sintering a plurality of green ceramic sheets, the thickness of the middle micro-channel layer (3) is not greater than 1 / 3 of the total thickness, and the thicknesses of the top cover layer (1) and the bottom substrate layer (4) are equal.

2. The microchannel LTCC substrate with an embedded micro-penetrating fin added according to claim 1, characterized in that, The radio frequency device unit (6) and the heat conduction columns (2) are arranged on the top cover layer (1), the heat conduction columns (2) are made of copper, and the heat conduction columns (2) can assist the radio frequency device unit (6) in efficiently transferring heat to the middle micro-channel layer (3).

3. The microchannel LTCC substrate with an embedded micro-penetrating fin added according to claim 1, characterized in that, ​

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