Method for improving power capacity of thick film integrated radio frequency device and radio frequency device

Abstract

A method for improving the power capacity of thick-film integrated radio frequency devices and radio frequency devices, including: providing at least three ceramic substrates; processing a thin metal layer and a conductor layer on the bottom surface of the first ceramic substrate; processing a thickened conductor layer on the top surface; arranging high-power devices and low-power devices on the thickened conductor layer; printing a thin-film dielectric layer on the high-power device using a thin-film process; and processing a conductor layer on the bottom surfaces of the remaining ceramic substrates; processing high-power grounding holes and low-power grounding holes on the corresponding ceramic substrates; processing multiple heat dissipation holes on all ceramic substrates, with the heat dissipation holes distributed around the thin-film dielectric layer; stacking the substrates and providing a heat sink at the bottom; firing and forming the substrates so that the low-power grounding holes are connected to the top surface of the third ceramic substrate for grounding, the large power grounding holes are connected to the top surface of the second ceramic substrate for grounding, and each heat dissipation hole is connected to the heat sink; and filling the heat dissipation holes with copper paste. This method improves the power capacity of radio frequency devices and radio frequency systems while meeting the requirements of a small-size design.

Description

Technical Field

[0001] The present application relates to the fields of thick film integrated circuits and radio frequency technology, and in particular to a method for improving the power capacity of a thick film integrated radio frequency device and a radio frequency device. Background Art

[0002] Thick-film integrated circuits, with their distinct advantages of high density, high performance, high reliability, light weight, and small size, have become a crucial component in the production of circuits for compact electronic systems. In modern radar, satellite communications, and other fields, transmitted signal power is increasing, while overall system size is shrinking, and integration is increasing, placing increasing demands on the power handling capabilities of thick-film circuits.

[0003] The increase in integration means an increase in the number of thick-film circuit layers, which is not conducive to the heat dissipation of the power circuit; the increase in signal power means that the transient current and transient power consumption of the circuit will increase, and the power capacity of the corresponding thick-film circuit must be increased; in addition, if thick-film process design is adopted, due to size and structural limitations, some heat dissipation measures and derating thermal design are also difficult to implement, resulting in excessive local heat, reduced system stability, and even the risk of burning; if local high-power devices are wired too densely, the local induced field strength will be too strong, causing local sparking phenomena such as air breakdown, burning the microstrip transmission line. Summary of the Invention

[0004] In order to address the deficiencies of the above-mentioned prior art, the present application provides a method for improving the power capacity of thick-film integrated RF devices and RF devices, thereby improving the power capacity of RF devices and RF systems while meeting small-size design requirements.

[0005] In order to achieve the above object, the present invention adopts the following technologies:

[0006] A method for improving the power capacity of a thick film integrated radio frequency device comprises the steps of:

[0007] Providing at least three ceramic substrates to be stacked in a top-down manner, forming a thin metal layer on the bottom surface of the first ceramic substrate, forming a conductor layer on the metal layer, forming a thickened conductor layer on the top surface of the ceramic substrate, and forming conductor layers on the bottom surfaces of the remaining ceramic substrates;

[0008] A high-power device and a low-power device are arranged on the thickened conductor layer, and a thin-film dielectric layer is formed on the high-power device using a thin-film printing process, the thin-film dielectric layer covers the high-power device, and a predetermined distance is provided between the thin-film dielectric layer and the low-power device;

[0009] A high-power grounding hole is machined through the first ceramic substrate, and the high-power grounding hole is located in the area where the thin-film dielectric layer is located. A low-power grounding hole is machined through the first two ceramic substrates, and multiple heat dissipation holes are machined on all ceramic substrates, and the heat dissipation holes are distributed around the thin-film dielectric layer. The position of the high-power device corresponds to the position of the high-power grounding hole, and the ground end of the high-power device is connected to the high-power grounding hole. The position of the low-power device corresponds to the position of the low-power grounding hole, and the ground end of the low-power device is connected to the low-power grounding hole.

[0010] Stacking multiple ceramic substrates in a planned order, and placing a heat sink under the last ceramic substrate;

[0011] Firing and molding, so that each low-power grounding hole is connected to the top surface of the third ceramic substrate to form a ground, so that each high-power grounding hole is connected to the top surface of the second ceramic substrate to form a ground, and so that each heat dissipation hole is connected to the heat sink;

[0012] Fill the heat dissipation holes with copper paste and solidify the copper paste.

[0013] Furthermore, when there are multiple high-power devices, they are arranged in a staggered manner on the thickened conductor layer.

[0014] A radio frequency device is obtained by adopting the method for improving the power capacity of a thick film integrated radio frequency device.

[0015] A radio frequency device comprises at least three ceramic substrates stacked and fired by a thick film process;

[0016] The bottom surface of the first ceramic substrate has a thin metal layer, the surface of the metal thin layer has a conductor layer, the top surface of the first ceramic substrate has a thickened conductor layer, and the bottom surfaces of the remaining ceramic substrates all have conductor layers; the surface of the conductor layer of the last ceramic substrate is provided with a heat sink;

[0017] A high-power device and a low-power device are provided on the thickened conductor layer, a thin-film dielectric layer is provided on the high-power device, the thin-film dielectric layer covers the high-power device, and a plurality of heat dissipation holes connected to the heat sink are provided on the peripheral side of the thin-film dielectric layer, and the heat dissipation holes contain solidified copper paste;

[0018] The grounding end of the high-power device is connected to the top surface of the second ceramic substrate through the high-power grounding hole to form grounding; the grounding end of the low-power device is connected to the top surface of the third ceramic substrate through the low-power grounding hole to form grounding.

[0019] The beneficial effects of the present invention are:

[0020] 1. While ensuring miniaturization and small size based on thick film integrated circuit technology, the area where the high-power device is located is covered with a thin film dielectric layer by thickening the conductor layer. The dielectric has a higher breakdown field strength threshold than air, which can increase the electric field breakdown threshold in the area where the high-power device is located, avoid local sparks, and increase power capacity; and through the multi-layer structure, the grounding of high-power devices and low-power devices is separated, cutting off the common channel of strong and weak currents, reducing common impedance, and eliminating cross interference;

[0021] 2. Compared with the conventional periodic distribution of conductor-ceramic substrate-conductor, the structure of thickened conductor layer-ceramic substrate-metal thin layer-conductor layer for high-power devices formed in the present invention can not only avoid the bending of the substrate caused by the different thermal expansion coefficients of the metal and ceramic substrates, but also alleviate the degree of bending; and the presence of the metal thin layer is equivalent to thickening the thickness of the ground plate of the high-power device, which can withstand a larger current and also improve the heat dissipation effect of the high-power device; and a heat sink is provided on the bottom layer of the last ceramic substrate, and heat dissipation by pouring copper slurry is more convenient to quickly conduct the heat loss of the surface layer with power devices and each weak signal layer to the heat sink; at the same time, the high-power device is arranged within the area formed by the heat dissipation hole, and the heat dissipation hole is located at the periphery of the power device, so as to facilitate the uniform downward conduction of the rapid heat loss of the high-power device;

[0022] 3. The high-power devices are staggered to evenly distribute heat, preventing heat accumulation from causing circuit deformation or burning. At the same time, the width of the metal conduction strips or microstrip lines corresponding to the high-power devices is set as large as possible to reduce impedance and lower the induced voltage intensity.

[0023] 4. By thickening the metal conductive layer, the cross-sectional area is increased, and its resistance will be reduced. Accordingly, the current intensity it can withstand can be increased, and horizontal heat dissipation performance will also be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flow chart of the method of an embodiment of the present application.

[0025] Figure 2 This is an exploded view of the radio frequency device structure of an embodiment of the present application.

[0026] Figure numerals: ceramic substrate-1, thickened conductor layer-10, thin film dielectric layer-11, high-power device-12, low-power device-13, conductor layer-2, metal thin layer-3, heat sink-4, high-power grounding hole-51, low-power grounding hole-52, heat dissipation hole-6. DETAILED DESCRIPTION

[0027] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the embodiments described in the present invention are only part of the embodiments of the present invention, rather than all the embodiments.

[0028] One aspect of the embodiments of the present application provides a method for improving the power capacity of a thick film integrated radio frequency device, such as Figure 1 The flowchart shown includes the following steps:

[0029] S100, providing at least three ceramic substrates 1 to be stacked from top to bottom, such as Figure 2 The illustrated example shows three ceramic substrates 1; the remaining number is not shown, but this does not affect the subsequent description and understanding of this embodiment. A thin metal layer 3 is formed on the bottom surface of the first ceramic substrate 1, and a conductor layer 2 is formed on the metal layer 3. A thickened conductor layer 10 is formed on the top surface of this ceramic substrate 1, with the thin film dielectric layer 11 occupying only a certain area in the center of the thickened conductor layer 10. Conductor layers 2 are formed on the bottom surfaces of the remaining ceramic substrates 1. Producing thin film dielectric layers 11 through a thin film printing process can increase the electric field breakdown threshold and power capacity of this region.

[0030] S200 , a high-power device 12 is arranged in a predetermined area (for example, in the middle area) on the top surface of the thickened conductive layer 10 , and a thin-film dielectric layer 11 is formed on the high-power device 12 by a thin-film printing process, so that the thin-film dielectric layer 11 covers the area where the high-power device 12 is located.

[0031] S300. A high-power grounding hole 51 is processed through the first ceramic substrate 1. The high-power grounding hole 51 is located in the area where the thin film dielectric layer 11 is located. Specifically, the high-power grounding hole 51 simultaneously penetrates the thickened conductor layer 10, the metal thin layer 3, and the conductor layer 2 on the bottom surface of the metal thin layer 3, so that the top layer is connected to the top surface of the second ceramic substrate 1 for grounding.

[0032] At the same time, a low-power grounding hole 52 is machined through the first two ceramic substrates 1, for example, Figure 2 In the example shown, two ceramic substrates 1 are processed, namely, a top layer and a second top layer.

[0033] A plurality of heat dissipation holes 6 are processed on all ceramic substrates 1 . During processing, the heat dissipation holes 6 are distributed around the thin film dielectric layer 11 , and each heat dissipation hole 6 is at a certain distance from the peripheral edge of the thin film dielectric layer 11 .

[0034] The position of the high-power device 12 corresponds to the position of the high-power grounding hole 51, and the grounding end of the high-power device 12 is connected to the high-power grounding hole 51; the low-power device 13 is set on the thickened conductor layer 10, and the position of the low-power device 13 corresponds to the position of the low-power grounding hole 52, and the grounding end of the low-power device 13 is connected to the low-power grounding hole 52. Specifically, Figure 2 In the example shown, there is a predetermined distance between the thin film dielectric layer 11 and the low-power device 13 , and the distance is as large as possible to keep high-power and low-power devices separated.

[0035] Specifically, the metal strip / microstrip / stripline used for electrical connection of the high-power device 12 is made as wide as possible (for example, several times the width of the metal strip of the low-power device 13) to reduce impedance, which can effectively reduce the induced voltage intensity of this part of the circuit. According to the relationship between impedance Z, power P and voltage U: P=U 2 / 2Z, it can be seen that when the input power is fixed, reducing the impedance Z can reduce the induced voltage U.

[0036] S400 , stacking a plurality of ceramic substrates 1 in a predetermined order, and stacking a heat sink 4 under the last ceramic substrate 1 .

[0037] S500 , firing and molding are performed, so that each low-power grounding hole 52 is connected to the top surface of the third ceramic substrate 1 to form a ground, and each high-power grounding hole 51 is connected to the top surface of the second ceramic substrate 1 to form a ground, and each heat dissipation hole 6 is connected to the heat sink 4.

[0038] S600 , filling the heat dissipation hole 6 with copper paste, and solidifying the copper paste.

[0039] By implementing the above steps, the power capacity of thick film integrated RF devices can be improved, and the grounding of high-power devices and low-power devices can be set separately, cutting off the common channel of strong and weak currents, reducing common impedance, and eliminating cross interference.

[0040] Compared with the conventional periodic distribution of conductor-ceramic substrate-conductor, the structure of thickened conductor layer 10-ceramic substrate 1-metal thin layer 3-conductor layer 2 can not only avoid the bending of the substrate due to the different thermal expansion coefficients of the metal and ceramic substrates, but also alleviate the degree of bending; and the presence of the metal thin layer 3 is equivalent to thickening the ground plate thickness of the high-power device, which can withstand larger currents and also improve the heat dissipation effect of the high-power device 12.

[0041] In this example, by using a metal thickened conductor layer 10 on the surface of the circuit that needs to withstand high power, the resistance of the metal thickened conductor layer 10 will decrease due to the increase in cross-sectional area, and accordingly, the current intensity it can withstand can be increased. In addition, the metal thickened conductor layer 10 will provide a horizontal heat dissipation effect.

[0042] As an optional implementation step, when arranging the high-power device 12 in S300, if there are multiple high-power devices 12, they are arranged in a staggered manner on the thickened conductor layer 10, so that heat can be evenly distributed and heat accumulation can be avoided to cause circuit deformation or circuit burning.

[0043] By implementing the above method, a thick-film integrated radio frequency device with improved power capacity can be obtained.

[0044] Another aspect of the present application provides a radio frequency device, such as Figure 2 As shown, it comprises at least three ceramic substrates 1 stacked and fired by a thick film process. The ceramic substrate layer 1 has good thermal conductivity and has an insulating isolation effect, which is beneficial to avoid inter-layer interference.

[0045] The bottom surface of the first ceramic substrate 1 has a thin metal layer 3, with a conductor layer 2 on its surface. The top surface of the first ceramic substrate 1 has a thickened conductor layer 10, with a high-power device 12 located within a predetermined area of the thickened conductor layer 10. The bottom surfaces of the remaining ceramic substrates 1 all have conductor layers 2. A thin-film dielectric layer 11 covers the high-power device 12, and the ground terminal of the high-power device 12 is connected to the top surface of the second ceramic substrate 1 through a high-power grounding hole 51, thereby establishing a ground connection. A low-power device 13 is located on the thickened conductor layer 10, and the ground terminal of the low-power device 13 is connected to the top surface of the third ceramic substrate 1 through a low-power grounding hole 52, thereby establishing a ground connection.

[0046] Finally, a heat sink 4 is provided on the surface of the conductor layer 2 of the ceramic substrate 1. A plurality of heat dissipation holes 6 connected to the heat sink 4 are provided around the thin film dielectric layer 11. The heat dissipation holes 6 contain solidified copper paste.

[0047] Among them, as a preferred method, the thickness of the topmost layer (i.e. the first layer from top to bottom) of the ceramic substrate 1 is less than the thickness of the remaining ceramic substrates 1. In this way, the thinner ceramic substrate 1 is used as the lining of the surface high-power device 12 circuit, and the thin substrate can more effectively conduct heat to the heat sink 4.

[0048] Specifically, in Figure 2 The illustrated example shows three ceramic substrates 1. However, according to the description of this example, the number of ceramic substrates 1 is not limited to three. As long as the positions and connections of the ceramic substrates 1 and the processing instructions of this example are met, this is also within the scope of this example. To avoid redundancy, the examples are not repeated here.

[0049] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit the present application. It is apparent that those skilled in the art may make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if such modifications and variations fall within the scope of the claims of the present application and their equivalents, the present application is intended to encompass such modifications and variations.

Claims

1. A method for improving the power capacity of a thick film integrated radio frequency device, characterized in that: Including steps: Providing at least three ceramic substrates (1) to be stacked in a top-down manner, processing a metal thin layer (3) on the bottom surface of the first ceramic substrate (1), processing a conductor layer (2) on the metal thin layer (3), processing a thickened conductor layer (10) on the top surface of the ceramic substrate (1), and processing the conductor layer (2) on the bottom surfaces of the remaining ceramic substrates (1); A high-power device (12) and a low-power device (13) are arranged on the thickened conductor layer (10), and a thin-film dielectric layer (11) is formed on the high-power device (12) using a thin-film printing process, wherein the thin-film dielectric layer (11) covers the high-power device (12); A high-power grounding hole (51) is formed through the first ceramic substrate (1), the high-power grounding hole (51) being located in the region where the thin-film dielectric layer (11) is located; a low-power grounding hole (52) is formed through the first two ceramic substrates (1); a plurality of heat dissipation holes (6) are formed on all ceramic substrates (1), the heat dissipation holes (6) being distributed around the thin-film dielectric layer (11); the position of the high-power device (12) corresponds to the position of the high-power grounding hole (51), and the grounding end of the high-power device (12) is connected to the high-power grounding hole (51); the position of the low-power device (13) corresponds to the position of the low-power grounding hole (52), and the grounding end of the low-power device (13) is connected to the low-power grounding hole (52); Stacking a plurality of ceramic substrates (1) in a predetermined order, and stacking a heat sink (4) below the last ceramic substrate (1); Sintering and forming, so that each low-power grounding hole (52) is connected to the top surface of the third ceramic substrate (1) to form a ground, so that each high-power grounding hole (51) is connected to the top surface of the second ceramic substrate (1) to form a ground, and so that each heat dissipation hole (6) is connected to the heat sink (4); The heat dissipation hole (6) is filled with copper paste, and the copper paste is solidified.

2. The method for improving the power capacity of thick film integrated radio frequency devices according to claim 1, characterized in that: When there are multiple high-power devices (12), they are arranged in a staggered manner on the thickened conductor layer (10).

3. The method for improving the power capacity of thick film integrated radio frequency devices according to claim 1, characterized in that: There is a predetermined distance between the thin film dielectric layer (11) and the low-power device (13).

4. The method for improving the power capacity of thick film integrated radio frequency devices according to claim 1, characterized in that: The thickness of the first ceramic substrate (1) is smaller than the thickness of the remaining ceramic substrates (1).

5. A radio frequency device, characterized in that: The method for improving the power capacity of thick film integrated radio frequency devices as claimed in claim 4 is used to obtain the device.

6. A radio frequency device, characterized in that: The invention comprises at least three ceramic substrates (1) stacked and fired by a thick film process; The bottom surface of the first ceramic substrate (1) has a metal thin layer (3), the surface of the metal thin layer (3) has a conductor layer (2), the top surface of the first ceramic substrate (1) has a thickened conductor layer (10), and the bottom surfaces of the remaining ceramic substrates (1) all have conductor layers (2); the surface of the conductor layer (2) of the last ceramic substrate (1) is provided with a heat sink (4); A high-power device (12) and a low-power device (13) are provided on the thickened conductor layer (10); a thin-film dielectric layer (11) is provided on the high-power device (12); the thin-film dielectric layer (11) covers the high-power device (12); a plurality of heat dissipation holes (6) connected to the heat sink (4) are provided on the peripheral side of the thin-film dielectric layer (11); the heat dissipation holes (6) have solidified copper paste; The grounding end of the high-power device (12) is connected to the top surface of the second ceramic substrate (1) through the high-power grounding hole (51) to form grounding; the grounding end of the low-power device (13) is connected to the top surface of the third ceramic substrate (1) through the low-power grounding hole (52) to form grounding.

7. The radio frequency device according to claim 6, characterized in that: When there are multiple high-power devices (12), they are arranged in a staggered manner on the thickened conductor layer (10).

8. The radio frequency device according to claim 6, characterized in that: There is a predetermined distance between the thin film dielectric layer (11) and the low-power device (13).

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