A snowflake-shaped heat dissipation structure for a heterogeneous integrated radio frequency front end

Abstract

The application discloses a snowflake-shaped heat dissipation structure for a heterogeneous integrated radio frequency front end and belongs to the technical field of radio frequency front end heat dissipation. The core structure of the design adopts a snowflake-shaped flow channel design. At a flow rate of 180 ml / min, the maximum temperature of a 50W heating element can be reduced to 54.4 DEG C under steady state, and the maximum pressure is 399.4 KPa, which are superior to the conventional method. Compared with the conventional scheme, the snowflake-shaped flow channel of the application can maintain a lower flow channel pressure while achieving higher heat dissipation efficiency, effectively relieving the heat dissipation pressure of the radio frequency front end.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio frequency microsystems, and in particular relates to a design method for a snowflake-shaped heat dissipation structure that can be used for a heterogeneous integrated radio frequency front end. Background Art

[0002] The evolution of wireless communication systems toward higher frequencies, wider bandwidths, higher power densities, and smaller form factors has made heterogeneous integration a key component in building high-performance, compact RF front-ends, such as phased array RF microsystems. Heterogeneous integration, through advanced packaging (such as 2.5D / 3D integration), enables high-density integration of GaN, Si, GaAs, and MEMS chips, significantly improving integration and performance. However, this high-density integration, particularly the use of GaN devices, leads to a dramatic increase in the system's heat dissipation density and difficulty, manifested in high surface and volume heat fluxes and thermal stacking effects. Heat dissipation has become a key bottleneck hindering the development of these highly integrated RF microsystems.

[0003] Current heterogeneous front-end cooling technologies can be broadly categorized into two types: passive and active. Passive cooling, while not relying on external energy, typically dissipates heat through heat plates and fins. Active cooling, on the other hand, relies on external energy (such as electricity or mechanical energy) to actively accelerate heat transfer through liquid circulation or phase change cooling. Currently, microfluidic technology is the primary representative of heterogeneous front-end cooling. Some microfluidic technologies employ biomimetic flow channel designs. In biomimetic heat dissipation flow channel designs, S-shaped channels introduce bends to increase the heat dissipation area, significantly improving heat exchange efficiency. However, the introduction of bends also significantly increases pipe pressure. Honeycomb channels utilize a regular hexagonal structure, which offers advantages such as uniform flow field distribution and low pressure drop. However, the improvement in heat dissipation performance is relatively limited. This paper proposes a novel snowflake heat dissipation flow channel structure designed to achieve the synergistic optimization of high-efficiency heat dissipation and low-pressure characteristics. Summary of the Invention

[0004] In response to the high heat flux density problems of heterogeneous integrated front-end systems, as well as the poor heat dissipation capacity of the flow channel and the high pressure of the flow channel, the present invention proposes a snowflake-shaped heat dissipation structure for a heterogeneous integrated RF front-end.

[0005] The present invention adopts the following technical solutions to solve the above technical problems:

[0006] The application discloses a snowflake-shaped heat dissipation structure for a heterogeneous integrated radio frequency front end.

[0007] The PCB plate also comprises a center part and a ring part surrounding the center part, the center part is molybdenum copper alloy, and the ring part has a size greater than that of the ring part of the silicon adapter plate.

[0008] The metal substrate is provided with a snowflake-shaped flow channel corresponding to the center part of the silicon adapter plate for heat dissipation.

[0009] Further, the snowflake-shaped flow channel in the metal substrate comprises three layers of flow channels from inside to outside, each layer is a regular hexagon, and each corner is treated with a rounded corner; a water inlet is introduced from one side and sequentially passes through the three layers of flow channels from outside to inside; a water outlet is introduced from the other side and sequentially passes through the middle layer of flow channels and the outer layer of flow channels from the inner layer of flow channels.

[0010] Further, each side of the three layers of flow channels in the snowflake-shaped flow channel is in a wave shape, and the wave shape is a trigonometric function.

[0011] Further, one side of the outer layer of flow channels, the middle layer of flow channels and the inner layer of flow channels comprises three, two and one complete wave periods in sequence.

[0012] Further, the thickness of the silicon adapter plate is 200 μm .

[0013] Further, the thickness of the heat chip layer is 0.1 mm.

[0014] Further, the thickness of the PCB plate is 1.4 mm.

[0015] Further, the thickness of the molybdenum copper alloy is 1.4 mm.

[0016] Further, the thickness of the metal substrate is 1.2 mm.

[0017] Further, the distance between the upper surface of the flow channel and the upper surface of the metal substrate is 0.2 mm, the distance between the lower surface of the flow channel and the lower surface of the metal substrate is 0.4 mm, and the height of the flow channel is 0.6 mm.

[0018] Compared with the prior art, the method has the following advantages:

[0019] The snowflake-shaped flow channel structure is innovatively designed. Under the conditions of a 50W heat source and an inlet water flow rate of 180ml / min, the steady-state maximum temperature and the flow channel pressure drop are significantly better than those of the traditional straight, S-shaped and honeycomb-shaped flow channels. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A snowflake-shaped heat dissipation structure stack for a heterogeneous integrated radio frequency front end is provided.

[0021] Figure 2 A snowflake-shaped flow channel structure is provided.

[0022] Figure 3 An S-shaped trigonometric function waveform is introduced in the honeycomb-shaped structure.

[0023] Figure 4 A steady-state high and low temperature comparison diagram obtained under the same simulation conditions for the four flow channels.

[0024] Figure 5 A steady-state high and low pressure comparison diagram obtained under the same simulation conditions for the four flow channels.

[0025] In the figure, 1 is a heat generating chip, 2 is an equivalent heat conduction via hole layer, 3 is a molybdenum copper alloy, and 4 is a snowflake-shaped flow channel. DETAILED DESCRIPTION

[0026] The snowflake-shaped heat dissipation structure applied to a heterogeneous integrated radio frequency front end system is innovatively provided. The core of the structure is to design a snowflake-shaped flow channel structure, which provides an efficient and reliable heat dissipation solution for the radio frequency front end system.

[0027] The overall heat dissipation architecture is shown in Figure 1 , which includes a substrate composed of three media, namely a silicon adapter plate, a PCB plate and a metal substrate. The thermal conductivity of the silicon adapter plate is 178 W / m·k , the thermal conductivity of the PCB plate is 0.2 W / m k , and the material of the metal substrate is copper, and the corresponding thermal conductivity is 400 W / m·k . The heat generating chip and the heat conduction via hole are embedded in the silicon adapter plate in a three-dimensional integrated manner. The heat generating chip simulates a GaN-based power amplifier chip, and the heat generating power under normal working condition is 50W, and the thermal conductivity of GaN is 220 W / m·k . The copper filled heat conduction via hole directionally conducts the heat generated by the power amplifier to the lower molybdenum copper alloy heat dissipation layer. Due to the excessive number of via holes in this layer, which is not conducive to simulation, the equivalent thermal conductivity is used instead of the material of this layer, the horizontal thermal conductivity is 203 W / m·k , and the vertical thermal conductivity is 156.75 W / m·k.The molybdenum-copper alloy below the thermal through hole is responsible for conducting heat from the thermal through hole to the snowflake-shaped flow channel below. The thermal conductivity of the molybdenum-copper alloy is 180 W / m·k The snowflake-shaped flow channel is located in the metal substrate below the molybdenum-copper alloy. The top of the flow channel is 0.2 mm away from the upper surface of the metal substrate, and the bottom of the flow channel is 0.4 mm away from the lower surface of the metal substrate. The liquid filled in the snowflake-shaped flow channel is water, and the thermal conductivity is 0.55. W / m·k .

[0028] Figure 2 The specific structure of the snowflake-shaped flow channel is shown. It consists of rectangular areas of water inlet / outlet on both sides and a three-layer regular hexagon + wave composite structure in the center. The central composite structure is based on three groups of regular hexagonal units of decreasing size. The units are connected through the rectangular areas of water inlet and outlet to form a base structure. On this base, trigonometric function wave paths (such as Figure 3 As shown, where W channel =0.3mm) to achieve wave feature integration: the outermost unit boundary is superimposed with a three-cycle function waveform, the middle layer is superimposed with a two-cycle trigonometric function waveform, and the innermost layer is superimposed with a single-cycle trigonometric function waveform, forming a gradient flow channel topology. At the same time, the sharp corners of the remaining base structure are rounded with a radius of 0.1mm. In addition, the width of the inlet and outlet is 0.3mm, the side length of the outermost regular hexagon is 3.05mm, the side length of the middle layer regular hexagon is 2.125mm, and the side length of the innermost regular hexagon is 1.175mm. The thickness of the snowflake flow channel is 0.6mm.

[0029] Under the conditions of 50W heat source and 180ml / min water cooling, the simulation results ( Figure 4-5 ) shows that the lowest temperature of the four flow channels is 25°C (ambient benchmark), and the highest temperature is distributed in a stepped manner: 71.9°C for the straight-type flow channel, 61.9°C for the honeycomb-type flow channel, 56.7°C for the S-type flow channel, and the snowflake-type flow channel achieves optimal heat dissipation at 54.4°C; in terms of pressure performance, the S-type flow channel has the largest pressure difference (inlet 2080kPa / outlet -430kPa), followed by the straight-type flow channel (707.75kPa / -128.76kPa), the snowflake-type flow channel is significantly optimized to 399.39kPa / -58.03kPa, and the honeycomb-type flow channel has the smallest pressure difference (318.53kPa / -59.27kPa). The snowflake-type flow channel achieves a breakthrough balance between efficient heat dissipation and low pressure.

Claims

1. A snowflake-shaped heat dissipation structure for a heterogeneous integrated radio frequency front end, characterized in that: The heat dissipation structure consists of the following three substrates: a silicon adapter board, a PCB board, and a metal substrate. The silicon adapter board includes a central portion and an annular portion surrounding the central portion. The annular portion is a ring of silicon-based material. The central portion includes two layers: the upper layer is a heat-generating chip layer, and the lower layer is an equivalent thermal via layer. The thermal via layer is provided with multiple thermal vias, and the thermal vias are filled with copper. The PCB also includes a central portion and an annular portion surrounding the central portion. The central portion is made of a molybdenum-copper alloy. The periphery of the central portion of the PCB is aligned with the central portion of the silicon adapter board. The periphery of the annular portion of the PCB is larger than that of the silicon adapter board. A snowflake-shaped flow channel is provided in the middle of the metal substrate corresponding to the center of the silicon adapter plate for heat dissipation; The snowflake-shaped flow channel in the metal substrate includes three layers of flow channels from the inside to the outside, each layer is a regular hexagon, and each corner is chamfered; the water inlet is introduced from one side and passes through the three layers of flow channels in sequence from the outside to the inside; the water outlet is led out from the other side, introduced from the inner layer flow channel, passed through the middle layer flow channel in sequence, and then led out from the outer layer flow channel.

2. A snowflake-shaped heat dissipation structure for a heterogeneous integrated radio frequency front end according to claim 1, characterized in that: The snowflake-shaped flow channel is composed of rectangular areas of water inlets and outlets on both sides and a central three-layer regular hexagon + wave composite structure; the central three-layer regular hexagon + wave composite structure is centered on three groups of regular hexagonal units of decreasing size, and the units are connected through the inlet and outlet rectangular areas to form a base structure; on this base, wave feature integration is achieved by superimposing trigonometric function waveform paths on the boundaries of the hexagonal units: the outermost unit boundary is superimposed with a three-period function waveform, the middle layer is superimposed with a double-period trigonometric function waveform, and the innermost layer is superimposed with a single-period trigonometric function waveform, forming a gradient flow channel topology.

3. The snowflake-shaped heat dissipation structure for a heterogeneous integrated radio frequency front end according to claim 2, characterized in that: The thickness of the silicon adapter plate is 200 μm .

4. The snowflake-shaped heat dissipation structure for a heterogeneous integrated radio frequency front end according to claim 2, wherein: The thickness of the heating chip layer is 0.1 mm.

5. The snowflake-shaped heat dissipation structure for heterogeneous integrated radio frequency front-end according to claim 2, characterized in that: The thickness of the PCB board is 1.4 mm.

6. The snowflake-shaped heat dissipation structure for heterogeneous integrated radio frequency front-end according to claim 2, characterized in that: The thickness of the molybdenum-copper alloy is 1.4 mm.

7. The snowflake-shaped heat dissipation structure for heterogeneous integrated radio frequency front-end according to claim 2, characterized in that: The thickness of the metal substrate is 1.2 mm.

8. The snowflake-shaped heat dissipation structure for heterogeneous integrated radio frequency front-end according to claim 2, characterized in that: The upper surface of the flow channel is 0.2 mm away from the upper surface of the metal substrate, the lower surface of the flow channel is 0.4 mm away from the lower surface of the metal substrate, and the flow channel height is 0.6 mm.

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