Split-level distribution microwave grounding hole structure for preventing scaling powder from overflowing

Abstract

The invention provides a staggered-layer distributed microwave grounding hole structure for preventing scaling powder from overflowing. According to the staggered-layer distributed microwave grounding hole structure, a traditional straight-through type grounding hole is changed into a staggered-layer distributed grounding hole. Through changing a straight-through grounding hole into a staggered grounding hole, a path of a capillary effect is cut off, and a scaling powder overflow phenomenon is prevented. Meanwhile, the heat dissipation characteristic and the grounding characteristic of the device are not affected, the damage risk of the microwave device is avoided, the reliability of aerospace products is improved, the batch production yield of the products is improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of high-frequency airtight microwave products, relates to the structural design of a multi-layer interconnection substrate, and specifically relates to a staggered-layer distributed microwave grounding hole structure for preventing flux overflow. Background Art

[0002] Microwave grounding in full-chip MCM micro-packaged microwave products usually uses straight-through grounding holes, which may cause flux overflow. After reflow soldering, a small amount of flux overflows directly above the straight-through grounding hole of the full-chip MCM micro-packaged microwave product; after atomization cleaning and baking, the flux begins to overflow in large quantities. After multiple baking and atomization cleaning, due to the lack of effective means to check whether flux remains in the welding layer, it is impossible to ensure that the flux is completely removed. If the flux is not completely removed, the module will still need to undergo high-temperature links such as conductive glue baking and pre-capping baking in the subsequent micro-assembly process, and the remaining flux may continue to overflow, which may eventually lead to failure of the PIND inspection. After reopening the cover, a large amount of flux still remains on the surface of the substrate, which will damage the microwave device for a long time. According to the current assessment standards, this type of microwave product is unqualified and cannot pass the assessment. If there are more straight-through grounding holes, the flux overflow phenomenon is more serious.

[0003] The phenomenon of flux overflowing along the straight-through grounding hole is mainly caused by the inherent characteristics of low-temperature co-fired ceramic (LTCC). The risks of flux overflow include: first, poor grounding, affecting the heat dissipation effect of the device; second, corrosion of microwave devices, degradation of electrical performance, and in severe cases, device failure; third, failure of the PIND inspection of micro-packaged microwave products, posing a huge threat to the yield rate.

[0004] Therefore, how to prevent flux overflow through microwave grounding holes in fully chip MCM micro-packaged microwave products is of great practical significance, improves the reliability of microwave devices, ensures the reliability of aerospace products, and has certain economic benefits. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a staggered distributed microwave grounding hole structure that prevents flux overflow, thereby solving the technical problem that flux is easily overflowed in the prior art full-chip MCM micro-packaged microwave products.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0007] A staggered microwave grounding hole structure for preventing solder flux from overflowing, the structure comprising a plurality of substrates, the plurality of substrates being stacked and arranged in layers in a vertical direction; a plurality of microwave grounding holes are respectively provided on each layer of the substrate; the number of the substrates is 4 to 6; the microwave grounding holes on at least two adjacent layers of the substrates are staggered and not connected, and the microwave grounding holes on at least two adjacent layers of the substrates are arranged one-to-one and connected.

[0008] The inner diameter of the microwave grounding hole is d T , 100μm≤d T ≤300μm.

[0009] The distance between two adjacent microwave grounding holes (2) located on the same layer of substrate (1) is G A , if the inner diameters of the two microwave grounding holes (2) are equal, then 2d T ≤G A ≤6d T If the inner diameters of the two microwave grounding holes (2) are not equal, let the inner diameter of one of the microwave grounding holes (2) be d T1 , the inner diameter of the other microwave grounding hole (2) is d T2 ,but

[0010] The distance between two adjacent microwave grounding holes (2) located on different layers of the substrate (1) and not connected is G B , if the inner diameters of the two microwave grounding holes (2) are equal, then d T ≤G B ≤3d T If the inner diameters of the two microwave grounding holes (2) are not equal, let the inner diameter of one of the microwave grounding holes (2) be d T3 , the inner diameter of the other microwave grounding hole (2) is d T4 ,but

[0011] The present invention also has the following technical features:

[0012] Preferably, the inner diameter d of the microwave grounding hole is T is 200μm.

[0013] Preferably, if the inner diameters of the two microwave grounding holes are equal, the distance G between the two adjacent microwave grounding holes on the same layer of substrate is A For 2d T If the inner diameters of the two microwave grounding holes are not equal, the distance G between the two adjacent microwave grounding holes on the same layer of substrate is A is d T1 With d T2 sum.

[0014] Preferably, if the inner diameters of the two microwave grounding holes are equal, the distance G between the two adjacent microwave grounding holes located on different layers of substrates and not connected is B For 2d T If the inner diameters of the two microwave grounding holes are not equal, the distance G between the two adjacent microwave grounding holes located on different layers of the substrate and not connected is B is d T3 With d T4 sum.

[0015] Specifically, the shortest distance between the microwave grounding hole and the edge of the substrate is I T1 , I T1 ≥200μm.

[0016] Specifically, the soldering flux used during the reflow soldering of the substrate is rosin soldering flux.

[0017] Specifically, the substrate is a low temperature co-fired ceramic substrate.

[0018] Specifically, a cavity is also provided on the substrate, and the shortest distance between the microwave grounding hole and the edge of the cavity is I T2 , I T2 ≥200μm.

[0019] Specifically, each layer of the substrate is provided with a plurality of heat dissipation holes, which are arranged at equal intervals along the horizontal and vertical directions; the structure formed by the plurality of heat dissipation holes is a heat dissipation hole matrix; the heat dissipation holes on each layer of the substrate are arranged one by one and are interconnected.

[0020] Specifically, the inner diameter of the heat dissipation hole is d S , 200μm≤d S ≤300μm.

[0021] Specifically, the distance between two adjacent heat dissipation holes on the same layer of substrate is G S , 3d S ≤G S ≤5d S , preferably G S =3d S .

[0022] Specifically, the length of the heat dissipation hole matrix is ​​L S , 4.5mm≤L S ≤6.5mm, preferably L S =6.5mm; the width of the heat dissipation hole matrix is ​​W S , 4.5mm≤W S ≤6.5mm, preferably W S =6.5mm.

[0023] Specifically, the shortest distance between the heat dissipation hole matrix and the edge of the substrate is I S , I S ≥2mm.

[0024] Compared with the prior art, the present invention has the following technical effects:

[0025] (I) The present invention changes the straight-through grounding hole into a staggered distributed grounding hole, thereby cutting off the path of the capillary effect, effectively preventing the flux from overflowing, reducing the baking time after atomization cleaning, greatly improving the mass production product rate, and enhancing the packaging performance; at the same time, it does not affect the heat dissipation and grounding characteristics of the device, avoids the risk of damage to the microwave device, improves the reliability of aerospace products, increases the mass production yield of the product, and reduces the production cost.

[0026] (II) The present invention distributes microwave grounding holes in staggered layers. When the microwave chip is a low-power device and the heat consumption of the power device does not exceed 0.4W, through thermal design simulation, the thermal design simulation comparison diagram of staggered microwave grounding holes and straight grounding holes is as follows: Figure 8 As shown. Microwave low-power devices are heat-dissipating designed, and the low-power devices are welded on the large area of ​​the microwave grounding hole designed with the offset hole. The thermal design simulation results show that the first-level derating design of the device is met, and the heat dissipation characteristics of the device are not affected. At the same time, the processing of multi-layer ceramic substrates only requires changing the silk screen and the leak board pattern, which does not require very complicated processes and will not bring additional production costs.

[0027] (III) The staggered distributed staggered grounding holes designed by the present invention will not affect the grounding impedance. According to the actual microwave product measurement of the process, the impedance value of the staggered distributed staggered grounding holes is about 150mΩ, which is the same as the impedance value of the straight-through grounding hole, and basically does not change, ensuring the grounding characteristics of the microwave device. The fully chip-based MCM micro-packaged microwave product has a wide range of practicality and is more suitable for high-frequency band applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a photo of a fully chip MCM micro-package microwave product with straight-through ground holes, showing flux overflow after the cover was opened.

[0029] Figure 2 This is a schematic diagram of the straight-through distributed microwave grounding hole structure of comparative example 1.

[0030] Figure 3 This is a schematic diagram of the staggered distributed microwave grounding hole structure for preventing flux overflow in Example 1.

[0031] Figure 4 Schematic diagram of the structure of a multi-layer interconnect substrate.

[0032] Figure 5Schematic diagram of parameters of staggered microwave grounding hole structure to prevent flux overflow.

[0033] Figure 6 This is a simulation comparison diagram of the S11 parameters of the staggered-layer distributed microwave grounding hole structure for preventing flux overflow of Example 1 and the straight-through distributed microwave grounding hole structure of Comparative Example 1.

[0034] Figure 7 This is a simulation comparison diagram of the S21 parameters of the staggered-layer distributed microwave grounding hole structure for preventing flux overflow of Example 1 and the straight-through distributed microwave grounding hole structure of Comparative Example 1.

[0035] Figure 8 It is a design simulation comparison diagram of the staggered distributed microwave grounding hole structure for preventing flux overflow of Example 1 and the straight-through distributed microwave grounding hole structure of Comparative Example 1.

[0036] Fig. 9 It is a schematic diagram of other layout methods of the staggered-layer distributed microwave grounding hole structure for preventing flux overflow of the present invention.

[0037] The meanings of the numbers in the figure are: 1-substrate, 2-microwave grounding hole, 3-cavity, 4-heat dissipation hole.

[0038] d T -Inner diameter of microwave grounding hole; G A - The distance between two adjacent microwave grounding holes on the same layer of substrate; G B - the distance between two adjacent microwave grounding holes located on different layers of substrates and not connected; T1 -The shortest distance between the microwave grounding hole and the edge of the substrate; I T2 -The shortest distance between the microwave grounding hole and the cavity edge; d S -Inner diameter of heat dissipation hole; G S - The distance between two adjacent heat dissipation holes on the same layer of substrate; L S -The length of the heat dissipation hole matrix; W S -Width of the heat dissipation hole matrix; I S -The shortest distance between the thermal via matrix and the substrate edge.

[0039] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0040] The design principle and ideas of the present invention are as follows:

[0041] Figure 1 The phenomenon of flux overflow caused by through-type microwave grounding vias is shown. Figure 2As shown in the figure, the straight-through grounding hole will cause abnormal metal protrusions on the surface of the ceramic substrate, causing airtightness problems after the microwave product is welded, resulting in failure of the PIND test. After reopening the cover, it was found that a large amount of flux still remained on the surface of the substrate. The microwave device will be damaged over a long period of time. According to the current assessment standards, the microwave product is unqualified and cannot pass the assessment.

[0042] The reason why the microwave straight-through grounding hole causes flux overflow has nothing to do with the filling fullness, co-firing process control, post-firing process control, and slurry conditions. The problem of flux overflowing along the straight-through grounding hole is caused by the inherent material characteristics of the LTCC multilayer ceramic substrate. Due to its own material characteristics, the multilayer ceramic substrate has a certain porosity in both the film layer and the metallized hole, which makes it difficult to achieve airtightness. Due to the slight differences in particle size, solid content, and component ratio between different batches of materials, the density of the sintered metallized holes is slightly different. When the pores of the metallized holes are larger than the molecular size of the flux, the flux in the solder layer liquefies when the module is heated, and overflows to the surface of the substrate along the pores under the action of the capillary effect. Since the pores of the metallized holes themselves are very small, as long as there are no macroscopic voids in the holes, a large amount of flux will not remain inside the substrate, which greatly reduces the risk of flux overflowing from the surface of the substrate and fundamentally eliminates the overflow of solder resist after baking.

[0043] Based on the above situation, the present invention designs a staggered distributed microwave grounding hole structure that prevents flux from overflowing, and changes the original straight-through grounding hole into a staggered hole grounding hole. In the fully chip MCM micro-packaged microwave product, it can ensure that there is no flux overflow after the final capping and baking. The number of stacked hole layers of this structure does not exceed 6 layers at most, and it is recommended not to exceed 4 layers. If it is not satisfied, at least 2 layers of through holes should be staggered, and it is ensured that the multi-layer ceramic substrate needs to have space to change the straight-through grounding into a staggered hole. After changing the straight-through grounding hole into a staggered hole grounding hole, the path of the capillary effect is cut off, which greatly reduces the risk of flux overflowing from the substrate surface, and fundamentally eliminates the problem of solder resist overflowing after baking before capping, which leads to the failure of the fully chip MCM micro-packaged microwave product assessment, and has higher reliability.

[0044] It should be noted that all electronic components, substrates and reagents used in the present invention, unless otherwise specified, are those known in the art. For example, substrate 1 is a substrate made of low temperature co-fired ceramic material known in the prior art. The soldering flux is a conventional rosin soldering flux known in the prior art.

[0045] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0046] Embodiment 1:

[0047] This embodiment provides a staggered microwave grounding hole structure for preventing flux overflow. Figure 4 As shown, the structure includes six substrates 1, which are stacked in layers in the vertical direction; the six substrates 1 are, from top to bottom, a first substrate 1, a second substrate 1, a third substrate 1, a fourth substrate 1, a fifth substrate 1 and a sixth substrate 1; and a plurality of microwave grounding holes 2 are respectively opened on each layer of the substrate 1.

[0048] like Figure 3 As shown, the microwave grounding holes 2 on the first substrate 1, the second substrate 1, the third substrate 1 and the fourth substrate 1 are all arranged in a one-to-one correspondence and are connected; the microwave grounding holes 2 on the fourth substrate 1 and the fifth substrate 1 are all staggered and not connected; the microwave grounding holes 2 on the fifth substrate 1 and the sixth substrate 1 are arranged in a one-to-one correspondence and are connected.

[0049] In this embodiment, the microwave grounding hole 2 ensures the grounding characteristics of the microwave device, and the microwave power device performs heat dissipation design.

[0050] As a specific solution of this embodiment, Figure 5 As shown, the inner diameter of the microwave grounding hole 2 [before sintering] is d T , 100μm≤d T ≤300μm, preferably d T =200μm.

[0051] As a specific solution of this embodiment, Figure 3 and Figure 5 As shown, the distance between two adjacent microwave grounding holes 2 located on the same layer of substrate 1 is G A , if the inner diameters of the two microwave grounding holes 2 are equal, then 2d T ≤G A ≤6d T , preferably G A =4d T If the inner diameters of the two microwave grounding holes 2 are not equal, let the inner diameter of one of the microwave grounding holes 2 be d T1 , the inner diameter of the other microwave grounding hole 2 is d T2 ,but Preferred G A =2(d T1 +d T2 ).

[0052] As a specific solution of this embodiment, Figure 3 As shown, the distance between two adjacent microwave grounding holes 2 (i.e., through holes of different signal networks in adjacent layers) located on different layers of substrate 1 and not connected is G BIf the inner diameters of the two microwave grounding holes 2 are equal, then d T ≤G B ≤3d T , preferably G B =2d T If the inner diameters of the two microwave grounding holes 2 are not equal, let the inner diameter of one of the microwave grounding holes 2 be d T3 , the inner diameter of the other microwave grounding hole 2 is d T4 ,but Preferred G B =d T3 +d T4 .

[0053] As a specific solution of this embodiment, Figure 5 As shown, the shortest distance between the microwave grounding hole 2 and the edge of the substrate is I T1 , I T1 ≥200μm.

[0054] As a specific solution of this embodiment, Figure 5 As shown, the substrate 1 is also provided with a cavity 3, and the shortest distance between the microwave grounding hole 2 and the edge of the cavity 3 is I T2 , I T2 ≥200μm. In this embodiment, the cavity 3 mainly ensures the grounding characteristics of the microwave device and performs heat dissipation design for the microwave power device.

[0055] As a specific solution of this embodiment, Figure 5 As shown, each layer of the substrate 1 is also provided with a plurality of heat dissipation holes 4, which are arranged at equal intervals along the transverse direction and the longitudinal direction; the structure formed by the plurality of heat dissipation holes 4 is a heat dissipation hole matrix; the heat dissipation holes 4 on each layer of the substrate 1 are arranged one by one and are interconnected.

[0056] As a specific solution of this embodiment, Figure 5 As shown, the inner diameter of the heat dissipation hole 4 [before sintering] is d S , 200μm≤d S ≤300μm, preferably d S = 200 μm; the distance between two adjacent heat dissipation holes 4 on the same layer of substrate 1 is G S , 3d S ≤G S ≤5d S , preferably G S =3d S .

[0057] As a specific solution of this embodiment, Figure 5 As shown, the length of the heat dissipation hole matrix is ​​L S , 4.5mm≤LS ≤6.5mm, preferably L S =6.5mm; the width of the heat dissipation hole matrix is ​​W S , 4.5mm≤W S ≤6.5mm, preferably W S =6.5mm.

[0058] As a specific solution of this embodiment, Figure 5 As shown, the shortest distance between the heat dissipation hole matrix and the edge of the substrate is I S , I S ≥2mm.

[0059] As a specific solution of this embodiment, the main component of the flux is rosin. When soldering with lead-tin solder, there will be solder resist residue in the solder, which will climb up along the microwave grounding through hole after being heated and overflow from the surface. The microwave grounding through hole is usually plugged, but the plugged hole is not airtight, and the flux will overflow under the capillary action.

[0060] As a specific solution of this embodiment, the engineering application of the multi-layer interconnect substrate with a staggered microwave grounding hole structure to prevent flux overflow includes: using lead-tin solder to brush between the bottom layer of the LTCC substrate and the tube shell, and putting it into a reflow oven for soldering. Finally, a multi-layer substrate with a staggered microwave grounding hole structure to prevent flux overflow is obtained, which effectively prevents the flux from climbing up, and even under the capillary action, it will only overflow to the middle layer of the substrate, and will not overflow the surface of the multi-layer substrate.

[0061] Comparative Example 1:

[0062] This comparative example provides a straight-through distributed microwave grounding hole structure, such as Figure 2 As shown, the main difference between this structure and embodiment 1 is that the microwave grounding holes 2 on the first substrate 1, the second substrate 1, the third substrate 1, the fourth substrate 1, the fifth substrate 1 and the sixth substrate 1 are all arranged in one-to-one correspondence and are connected.

[0063] Effect verification of Example 1 and Comparative Example 1:

[0064] The present invention uses HFSS three-dimensional electromagnetic field model to simulate and verify the microwave grounding performance. After optimization simulation, the simulation results are as follows Figure 6 and Figure 7 As shown, the DC characteristics of the staggered distributed staggered grounding hole of Example 1 and the straight-through grounding hole of Comparative Example 1 are compared. The loss of both is better than 0.003dB, and the return loss is better than 60dB, so it will not affect the grounding impedance and grounding performance. At the same time, according to engineering measurements, the impedance value of the staggered distributed staggered grounding hole is about 150mΩ, which is the same as the impedance value of the straight-through grounding hole, and there is basically no change. It can be seen that it has excellent microwave grounding characteristics.

[0065] The microwave grounding heat dissipation characteristics of the present invention are subjected to thermal design simulation and comparative analysis. Figure 8 It can be seen that the staggered distributed microwave grounding holes proposed in Example 1, through the staggered distributed microwave grounding holes, when the heat consumption of the microwave power device does not exceed 0.4W, it can be seen from the simulation analysis results that under the same working conditions, the thermal design simulation comparison diagram of the staggered distributed microwave grounding holes and the straight grounding holes is as follows: Figure 8 As shown in the figure, the thermal design simulation results show that the heat dissipation path of the staggered microwave grounding holes is longer than that of the straight grounding holes, the temperature rise is 1.5℃, and the first-level derating temperature of the power device is 110℃, both of which meet the first-level derating design of the device, proving that the thermal design of the staggered microwave grounding holes and the straight grounding holes is reasonable and does not affect the heat dissipation characteristics of the power device.

[0066] Embodiment 2:

[0067] This embodiment provides a staggered microwave grounding hole structure for preventing flux overflow. Fig. 9 As shown in (A), the structure is basically the same as that of Example 1, except that: the microwave grounding holes 2 on the first substrate 1, the second substrate 1 and the third substrate 1 are all arranged in one-to-one correspondence and are connected; the microwave grounding holes 2 on the third substrate 1 and the fourth substrate 1 are not connected; the microwave grounding holes 2 on the fourth substrate 1, the fifth substrate 1 and the sixth substrate 1 are all arranged in one-to-one correspondence and are connected.

[0068] Embodiment 3:

[0069] This embodiment provides a staggered microwave grounding hole structure for preventing flux overflow. Fig. 9 As shown in (B), the structure is basically the same as that of Example 1, except that: the microwave grounding holes 2 on the first substrate 1 and the second substrate 1 are connected; the microwave grounding holes 2 on the second substrate 1 and the third substrate 1 are not connected; the microwave grounding holes 2 on the third substrate 1 and the fourth substrate 1 are connected; the microwave grounding holes 2 on the fourth substrate 1 and the fifth substrate 1 are not connected; the microwave grounding holes 2 on the fifth substrate 1 and the sixth substrate 1 are connected.

[0070] Embodiment 4:

[0071] This embodiment provides a staggered microwave grounding hole structure for preventing flux overflow. Fig. 9As shown in (C), the structure is basically the same as Example 1, except that: the structure includes five substrates 1, and the five substrates 1 are stacked in layers in the vertical direction; the five substrates 1 are, from top to bottom, the first substrate 1, the second substrate 1, the third substrate 1, the fourth substrate 1 and the fifth substrate 1; a plurality of microwave grounding holes 2 are respectively opened on each layer of the substrate 1; the microwave grounding holes 2 on the first substrate 1, the second substrate 1 and the third substrate 1 are all arranged in a one-to-one correspondence and are connected; the microwave grounding holes 2 on the third substrate 1 and the fourth substrate 1 are not connected; the microwave grounding holes 2 on the fourth substrate 1 and the fifth substrate 1 are connected.

[0072] Embodiment 5:

[0073] This embodiment provides a staggered microwave grounding hole structure for preventing flux overflow. Fig. 9 As shown in (D), the structure is basically the same as that of Example 4, except that: the microwave grounding holes 2 on the first substrate 1 and the second substrate 1 are connected; the microwave grounding holes 2 on the second substrate 1 and the third substrate 1 are not connected; the microwave grounding holes 2 on the third substrate 1, the fourth substrate 1 and the fifth substrate 1 are connected.

[0074] Embodiment 6:

[0075] This embodiment provides a staggered microwave grounding hole structure for preventing flux overflow. Fig. 9 As shown in (E), the structure is basically the same as Example 1, except that: the structure includes four substrates 1, and the four substrates 1 are stacked in layers in the vertical direction; the four substrates 1 are, from top to bottom, a first substrate 1, a second substrate 1, a third substrate 1 and a fourth substrate 1; a plurality of microwave grounding holes 2 are respectively opened on each layer of the substrate 1; the microwave grounding holes 2 on the first substrate 1 and the second substrate 1 are connected; the microwave grounding holes 2 on the second substrate 1 and the third substrate 1 are not connected; the microwave grounding holes 2 on the third substrate 1 and the fourth substrate 1 are connected.

Claims

1. A staggered microwave grounding hole structure for preventing flux overflow, the structure comprising a plurality of substrates (1), wherein the plurality of substrates (1) are stacked and arranged in layers in a vertical direction; a plurality of microwave grounding holes (2) are respectively opened on each layer of the substrates (1); the structure is characterized in that: The number of the substrates (1) is 4 to 6; the microwave grounding holes (2) on at least two adjacent layers of substrates (1) are staggered and not connected, and the microwave grounding holes (2) on at least two adjacent layers of substrates (1) are arranged in a one-to-one correspondence and are connected; The inner diameter of the microwave grounding hole (2) is d T , 100μm≤d T ≤300μm; The distance between two adjacent microwave grounding holes (2) located on the same layer of substrate (1) is G A , if the inner diameters of the two microwave grounding holes (2) are equal, then 2d T ≤G A ≤6d T If the inner diameters of the two microwave grounding holes (2) are not equal, let the inner diameter of one of the microwave grounding holes (2) be d T1 , the inner diameter of the other microwave grounding hole (2) is d T2 ,but The distance between two adjacent microwave grounding holes (2) located on different layers of the substrate (1) and not connected is G B , if the inner diameters of the two microwave grounding holes (2) are equal, then d T ≤G B ≤3d T If the inner diameters of the two microwave grounding holes (2) are not equal, let the inner diameter of one of the microwave grounding holes (2) be d T3 , the inner diameter of the other microwave grounding hole (2) is d T4 ,but 2. The staggered-layer distributed microwave grounding hole structure for preventing flux overflow as claimed in claim 1, characterized in that: The shortest distance between the microwave grounding hole (2) and the edge of the substrate is I T1 , I T1 ≥200μm.

3. The staggered-layer distributed microwave grounding hole structure for preventing flux overflow as claimed in claim 1, characterized in that: The soldering flux used in the reflow soldering of the substrate (1) is rosin soldering flux.

4. The staggered-layer distributed microwave grounding hole structure for preventing flux overflow as claimed in claim 3, characterized in that: The substrate (1) is a low temperature co-fired ceramic substrate.

5. The staggered-layer distributed microwave grounding hole structure for preventing flux overflow as claimed in claim 1, characterized in that: The substrate (1) is also provided with a cavity (3), and the shortest distance between the microwave grounding hole (2) and the edge of the cavity (3) is I T2 , I T2 ≥200μm.

6. The staggered-layer distributed microwave grounding hole structure for preventing flux overflow as claimed in claim 1, characterized in that: Each layer of the substrate (1) is also provided with a plurality of heat dissipation holes (4), and the plurality of heat dissipation holes (4) are arranged at equal intervals in the transverse direction and the longitudinal direction; the structure formed by the plurality of heat dissipation holes (4) is a heat dissipation hole matrix; the heat dissipation holes (4) on each layer of the substrate (1) are arranged in a one-to-one correspondence and are interconnected.

7. The staggered-layer distributed microwave grounding hole structure for preventing flux overflow as claimed in claim 6, characterized in that: The inner diameter of the heat dissipation hole (4) is d S , 200μm≤d S ≤300μm.

8. The staggered-layer distributed microwave grounding hole structure for preventing flux overflow as claimed in claim 6, characterized in that: The distance between two adjacent heat dissipation holes (4) located on the same layer of substrate (1) is G S , 3d S ≤G S ≤5d S .

9. The staggered-layer distributed microwave grounding hole structure for preventing flux overflow as claimed in claim 6, characterized in that: The length of the heat dissipation hole matrix is ​​L S , 4.5mm≤L S ≤6.5mm; the width of the heat dissipation hole matrix is ​​W S , 4.5mm≤W S ≤6.5mm.

10. The staggered-layer distributed microwave grounding hole structure for preventing flux overflow as claimed in claim 6, characterized in that: The shortest distance between the heat dissipation hole matrix and the edge of the substrate is I S , I S ≥2mm.

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