Microwave chip eutectic soldering platform and eutectic soldering method

Abstract

The present invention provides a microwave chip eutectic soldering platform and an eutectic soldering method, belonging to the technical field of chip packaging. The microwave chip eutectic soldering platform includes a housing, a heating platform, and a working platform; the top of the housing is open; the heating platform is arranged inside the housing and is used for electrically connecting with an external power supply; the working platform is arranged inside the housing, and the bottom surface thereof is attached to the top surface of the heating platform; a plurality of working areas are arranged on the top surface of the working platform, and the plurality of working areas are respectively used for placing metal carriers of different sizes; wherein, vacuum adsorption holes for communicating with a vacuum pump pipeline are respectively arranged in the plurality of working areas, the vacuum adsorption holes are used for adsorbing the metal carriers, and the aperture of the vacuum adsorption holes in each working area is proportional to the size of the placement surface of the metal carrier. The microwave chip eutectic soldering platform provided by the present invention is applicable to welding operations of different models of microwave chips. The present invention also provides an eutectic soldering method.

Description

Technical Field

[0001] The present invention belongs to the technical field of chip packaging, and more specifically, relates to a eutectic soldering platform and a eutectic soldering method for microwave chips. Background Art

[0002] Eutectic soldering is a common microwave chip packaging process. By heating and melting the solder sheet at high temperature, a eutectic alloy is formed between the chip and the metal carrier, thus connecting them into one body. There are three common ways of eutectic soldering for microwave chips, namely vacuum eutectic soldering using a vacuum packaging furnace, automatic friction eutectic soldering using a pick-and-place machine, and manual friction eutectic soldering with tweezers holding the chip. The equipment required for the first two methods is expensive, and customized tooling fixtures need to be made for different models (sizes) of microwave chips. Therefore, there are problems of poor versatility, high cost, and long cycle. For the production requirements of multiple varieties and small batches, the manual friction eutectic soldering method is usually adopted.

[0003] The traditional manual friction eutectic soldering uses a soldering platform that fixes the metal carrier on the heating workbench with a spring clamp, places the solder sheet on the metal carrier, and after the solder sheet melts, uses tweezers to hold the chip for friction soldering. This method is inconvenient to operate in a high-temperature environment and is prone to scalding the operator because it requires manual adjustment of the position of the spring clamp baffle to clamp the metal carrier. Moreover, it cannot ensure a stable and appropriate clamping force for metal carriers of different sizes. Especially for small-sized metal carriers, the clamping stability is poor, and it is easy to cause the metal carrier to shake or fly off during the friction soldering process. Summary of the Invention

[0004] The purpose of the present invention is to provide a eutectic soldering platform and a eutectic soldering method for microwave chips, aiming to solve the problems in the prior art that the manual friction eutectic soldering tooling for microwave chips is not flexible in switching between metal carriers of different sizes and has poor clamping stability for small-sized metal carriers.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a eutectic soldering platform for microwave chips, including a housing, a heating platform, and a working platform; the top of the housing is open; the heating platform is arranged inside the housing and is used for electrical connection with an external power supply; the working platform is arranged inside the housing, and the bottom surface thereof is attached to the top surface of the heating platform; a plurality of working areas are provided on the top surface of the working platform, and the plurality of working areas are respectively used for placing metal carriers of different sizes; wherein, vacuum adsorption holes for communicating with a vacuum pump pipeline are respectively provided in the plurality of working areas, the vacuum adsorption holes are used for adsorbing the metal carriers, and the aperture of the vacuum adsorption holes in each working area is proportional to the size of the placement surface of the metal carrier.

[0006] As another embodiment of the present application, a plurality of vacuum adsorption holes are arranged at intervals in each working area. When the metal carrier is placed on the working area, at least two adjacent vacuum adsorption holes are located below the metal carrier.

[0007] As another embodiment of the present application, a plurality of ventilation holes are arranged inside the working platform. The plurality of ventilation holes correspond to the plurality of working areas one by one. The plurality of ventilation holes are respectively used to communicate with the vacuum pump pipeline. The vacuum adsorption holes extend downward from the top surface of the working platform and communicate with the corresponding ventilation holes.

[0008] As another embodiment of the present application, the ventilation holes extend along the radial direction of the working platform from the side wall of the working platform, and the plurality of ventilation holes communicate with each other. One of the ventilation holes is used to connect the vacuum pump pipeline, and plug heads are respectively arranged at the openings of the remaining ventilation holes.

[0009] As another embodiment of the present application, a plurality of nitrogen pipes penetrate through the side wall of the housing. The outlet ends of the plurality of nitrogen pipes respectively penetrate into the interior of the housing and extend obliquely downward, and are respectively aligned with each working area. The plurality of nitrogen pipes are respectively used to connect the nitrogen gas source.

[0010] As another embodiment of the present application, a nitrogen gas retaining ring is arranged on the inner wall of the top end of the housing.

[0011] As another embodiment of the present application, a sealing plate is covered on the top surface of the working platform. When the metal carrier is placed on the working area corresponding to its size for operation, the sealing plate is used to block the vacuum adsorption holes of the remaining working areas.

[0012] As another embodiment of the present application, a fixing shaft extending vertically upward is arranged on the top surface of the working platform. The plurality of working areas are distributed at intervals along the circumferential direction of the fixing shaft. The sealing plate is semicircular or a sector with a central angle greater than 180°, and the sealing plate is rotationally connected to the fixing shaft.

[0013] As another embodiment of the present application, a screw nut is threadedly connected to the extending end of the fixing shaft. A spring is sleeved on the fixing shaft. One end of the spring abuts against the top surface of the sealing plate, and the other end abuts against the bottom surface of the screw nut.

[0014] The beneficial effects of the eutectic soldering platform for microwave chips provided by the present invention are as follows: Compared with the prior art, in the eutectic soldering platform for microwave chips of the present invention, there are multiple working areas on the working platform, and vacuum adsorption holes suitable for adsorbing metal carriers of different sizes are respectively provided in the multiple working areas. Operators can select the corresponding working area according to the size of the metal carrier, so that the vacuum adsorption holes in the working area adsorb and fix the metal carrier. The fixation of the metal carrier is simple, the operation is convenient, the adsorption is stable and reliable, and metal carriers of different sizes can select different working areas for adsorption and fixation, and the fixation position can be flexibly switched. Especially for small-sized metal carriers, stable adsorption and fixation can also be ensured. It can be applied to the manual friction eutectic soldering process of different models of microwave chips, with high versatility, suitable for the eutectic soldering operation of multi-variety and small-batch microwave chips, and is particularly important for the popularization and application of MEMS (Micro-Electro-Mechanical System) circulators in the 5G communication field.

[0015] The present invention also provides a method for eutectic soldering of microwave chips, including the following steps:

[0016] Power on and heat the working platform of any one of the above-mentioned eutectic soldering platforms for microwave chips, with the heating temperature being 183 - 380 °C, and turn on the vacuum pump;

[0017] Vacuum adsorb the tinned board in the working area on the working platform that matches the size of the tinned board, place solder on the tinned board for heating and melting, and place the back of the microwave chip on the melted solder for friction tinning;

[0018] Remove the microwave chip after tinning for natural air cooling, and remove the tinned board;

[0019] Place the metal carrier to be welded on the working platform, and vacuum adsorb the metal carrier through the vacuum adsorption holes in the working area corresponding to the size of the metal carrier;

[0020] Place solder on the top surface of the metal carrier for tinning, and after tinning is completed, remove the metal carrier for natural air cooling;

[0021] Place the microwave chip after tinning and air cooling on the corresponding position on the metal carrier after tinning and air cooling;

[0022] Place the metal carrier with the microwave chip placed on it in the corresponding working area on the working platform, and perform vacuum adsorption through the vacuum adsorption holes;

[0023] After the solder in the tinning layer on the top surface of the metal carrier and the bottom surface of the microwave chip is heated and melted, clamp the microwave chip and perform circular friction on the metal carrier for 3 - 5 weeks or cross reciprocating friction for 3 - 5 times;

[0024] After the solder of the tinned layer is melted, the metal carrier and the microwave chip are removed from the microwave chip eutectic welding platform and cooled naturally, and the welding is completed.

[0025] The beneficial effect of the microwave chip eutectic welding method provided by the present invention is that: compared with the prior art, in addition to the beneficial effects of the above-mentioned microwave chip eutectic welding platform, the microwave chip eutectic welding method of the present invention can also, before welding, perform tinned treatment on the bottom surface of the microwave chip and the surface of the metal carrier on the above-mentioned microwave chip eutectic welding platform respectively, so that a good solder layer is formed on the bottom surface of the microwave chip and the top surface of the metal carrier after tinning. During welding, only the solder of the tinned layer on the bottom surface of the microwave chip and the top surface of the metal carrier needs to be heated and melted, and no additional solder needs to be added. It can avoid the situation of high welding void ratio caused by poor cleanliness of the bottom surface of the microwave chip or the surface of the metal carrier, plating defects, or solder oxidation and other factors, thereby reducing the welding void ratio and improving the yield of the microwave chip eutectic welding operation. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 It is a schematic three-dimensional structure diagram of the microwave chip eutectic welding platform provided by the embodiment of the present invention;

[0028] Figure 2 For Figure 1 The partial enlarged view at A in

[0029] Figure 3 For the sectional view taken along the line B-B in Figure 1 It is a sectional structure diagram;

[0030] Figure 4 For the sectional view taken along the line C-C in Figure 1 It is a sectional structure diagram;

[0031] Figure 5 It is a schematic three-dimensional structure diagram of the working platform adopted by the embodiment of the present invention;

[0032] Figure 6 It is a schematic cross-sectional structure diagram of the working platform adopted by the embodiment of the present invention;

[0033] Figure 7 It is a schematic three-dimensional structure diagram of the sealing plate adopted by the embodiment of the present invention;

[0034] Figure 8Flow chart of the eutectic soldering method for microwave chips provided by the embodiments of the present invention.

[0035] In the figure: 100, housing; 101, nitrogen pipe; 102, nitrogen baffle ring; 200, heating platform; 201, temperature controller; 300, working platform; 301, vacuum adsorption hole; 302, sealing plate; 303, fixed shaft; 304, screw nut; 305, spring; 306, ventilation hole; 307, plug; 400, vacuum pump pipeline; 501, first area; 502, second area; 503, third area; 504, fourth area. Detailed implementation manners

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] Please refer to Figure 1 、 Figures 3 to 5 , and now the eutectic soldering platform for microwave chips provided by the present invention will be described. The eutectic soldering platform for microwave chips includes a housing 100, a heating platform 200 and a working platform 300; the top of the housing 100 is open; the heating platform 200 is arranged inside the housing 100 and is used for electrically connecting with an external power supply; the working platform 300 is arranged inside the housing 100, and the bottom surface thereof is attached to the top surface of the heating platform 200; the top surface of the working platform 300 is provided with a plurality of working areas, and the plurality of working areas are respectively used for placing metal carriers of different sizes; wherein, the plurality of working areas are respectively provided with vacuum adsorption holes 301 communicated with the vacuum pump pipeline 400, the vacuum adsorption holes 301 are used for adsorbing the metal carriers, and the aperture of the vacuum adsorption holes 301 in each working area is proportional to the size of the placement surface of the metal carrier.

[0038] The working principle of the eutectic soldering platform for microwave chips provided by the present invention: Before the soldering operation, the heating platform 200 is first powered on for heating. It should be noted that as a commonly used heating method in the prior art, a temperature controller 201 is embedded on the heating platform 200, and the heating temperature of the heating platform 200 can be controlled through the temperature controller 201. The working platform 300 attached to the top surface of the heating platform 200 is heated by heat transfer through the heating platform 200. At the same time, the vacuum pump is also turned on to generate negative pressure at the mouths of the respective vacuum adsorption holes 301 connected to the vacuum pump. When the metal carrier is placed in the working area and above the vacuum adsorption holes 301, it is fixed by the adsorption force of the vacuum adsorption holes 301. Then, a solder sheet or other forms of solder are placed on the metal carrier, and the metal carrier is heated by heat transfer from the working platform 300 to melt the solder, and then the microwave chip is clamped and placed on the metal carrier for manual friction eutectic soldering.

[0039] It should be understood here that the aperture of the vacuum adsorption holes 301 in each working area is proportional to the size of the placement surface of the metal carrier. The larger the aperture of the vacuum adsorption holes 301, the greater the adsorption force. Therefore, a metal carrier with a large size should be placed in the working area with vacuum adsorption holes 301 having a large aperture for adsorption and fixation. On the contrary, a metal carrier with a small size should be placed in the working area with vacuum adsorption holes 301 having a small aperture for adsorption and fixation.

[0040] In addition, since there is air flow through the vacuum adsorption holes 301, it has a certain heat dissipation effect on the working platform 300, resulting in heat loss. Moreover, the larger the aperture, the faster the heat dissipation. Especially for a metal carrier with a small size, if the area of the vacuum adsorption holes 301 occupying the placement surface of the metal carrier is larger, the heating effect of the metal carrier is worse, and the heating temperature of the working platform 300 needs to be increased to ensure that the solder transferred above the metal carrier melts, which easily leads to too high a temperature transferred to the microwave chip and causes thermal damage to the microwave chip. Therefore, when the sufficient adsorption force for the metal carrier can be satisfied, vacuum adsorption holes 301 with a smaller aperture should be selected for adsorption and fixation.

[0041] Compared with the prior art, the microwave chip eutectic welding platform provided by the present invention has multiple working areas on the working platform 300, and vacuum adsorption holes 301 suitable for adsorbing metal carriers of different sizes are respectively arranged in the multiple working areas. The operator can select the corresponding working area according to the size of the metal carrier, so that the vacuum adsorption holes 301 in the working area adsorb and fix the metal carrier. The fixation of the metal carrier is simple, the operation is convenient, the adsorption is stable and reliable. Metal carriers of different sizes can select different working areas for adsorption and fixation, and the conversion of the fixation position is flexible and convenient. Especially for small-sized metal carriers, stable adsorption and fixation can also be ensured. It can be applied to the manual friction eutectic welding process of different types of microwave chips, with high versatility, and is suitable for the eutectic welding operation of multi-variety and small-batch microwave chips. Especially, it has important significance for the popularization and application of MEMS circulators in the 5G communication field.

[0042] As a specific implementation manner of the microwave chip eutectic welding platform provided by the present invention, please refer to Figure 5 , a plurality of vacuum adsorption holes 301 are arranged at intervals in each working area. When the metal carrier is placed in this working area, at least two adjacent vacuum adsorption holes 301 are located below the metal carrier.

[0043] A plurality of vacuum adsorption holes 301 are arranged at intervals within each working area. Of course, the distance between adjacent vacuum adsorption holes 301 should be less than the size of the metal carrier, so as to ensure that when the metal carrier is placed on the working area, at least two adjacent vacuum adsorption holes 301 are located below the placement surface of the metal carrier for joint adsorption (the distance between adjacent vacuum adsorption holes 301 can be set to be less than half of the size of the metal carrier, so that no matter where the metal carrier is placed within the working area, at least two vacuum adsorption holes 301 can be covered, which is convenient for the placement of the metal carrier).

[0044] By jointly adsorbing and fixing the metal carrier through at least two vacuum adsorption holes 301, on the one hand, it can prevent the metal carrier from rotating during the process of the microwave chip performing circular friction (usually in the way of circular friction or cross friction) on the metal carrier (if only one vacuum adsorption hole 301 is used for adsorption and fixation, this phenomenon is likely to occur). On the other hand, using at least two vacuum adsorption holes 301 for joint adsorption can reduce the aperture of a single vacuum adsorption hole 301 (the joint adsorption force of at least two small-aperture vacuum adsorption holes 301 is not less than the adsorption force of a single large-aperture vacuum adsorption hole 301), avoiding large heat loss caused by too large an aperture of the vacuum adsorption hole 301, so that it is necessary to increase the heating temperature of the working platform 300 to melt the solder, and then resulting in too high a temperature transmitted to the microwave chip and causing thermal damage to the microwave chip.

[0045] In this embodiment, please refer to Figure 5 , the distance between the plurality of vacuum adsorption holes 301 in each working area is proportional to the size of the placement surface of the metal carrier. If the size of the metal carrier is large, the covered area is large. Therefore, for adjacent vacuum adsorption holes 301, a larger distance can be set to avoid the serious heat loss caused by too dense vacuum adsorption holes 301, and thus avoid thermal damage to the microwave chip due to too high a heating temperature of the working platform 300 required for solder melting. Of course, if the size of the metal carrier is small, the covered area is small. Therefore, a smaller distance between adjacent vacuum adsorption holes 301 is required to ensure that at least two vacuum adsorption holes 301 jointly adsorb and fix the metal carrier.

[0046] Refer to Figure 5, the top surface of the working platform 300 can be equally divided into four working areas. The aperture diameter and hole pitch of the vacuum adsorption holes 301 in the first area 501 are both set to 0.6 mm, those in the second area 502 are both set to 1 mm, those in the third area 503 are both set to 1.5 mm, and those in the fourth area 504 are both set to 2 mm. Each area corresponds to adsorbing metal carriers of different sizes. For example, a metal carrier with a size of 2.8×1.75 mm is selected to be placed and adsorbed in the first area 501, and a metal carrier with a size of 5×7 mm is selected to be placed and adsorbed in the fourth area 504.

[0047] As a specific implementation manner of the embodiment of the present invention, please refer to Figure 5 and Figure 6 , there are multiple vent holes 306 inside the working platform 300. The multiple vent holes 306 correspond to the multiple working areas one by one. The multiple vent holes 306 are respectively used to connect to the vacuum pump pipeline 400. The vacuum adsorption holes 301 extend downward from the top surface of the working platform 300 and are communicated with the corresponding vent holes 306.

[0048] In this embodiment, please refer to Figure 4 and Figure 6 , the vent holes 306 extend along the radial direction of the working platform 300 from the side wall of the working platform 300, and the multiple vent holes 306 are communicated with each other. One of the vent holes 306 is used to connect to the vacuum pump pipeline 400, and plug heads 307 are respectively provided at the openings of the remaining vent holes 306. By connecting the opening of one vent hole 306 to the vacuum pump pipeline 400, all the vacuum adsorption holes 301 can be connected to the vacuum pump. During processing, drilling can be performed from the side wall of the working platform 300, and after processing, the plug heads 307 are installed for plugging. The processing is convenient and the manufacturing cost is low.

[0049] As a specific implementation manner of the embodiment of the present invention, please refer to Figure 1 , Figure 3 and Figure 4 , a plurality of nitrogen pipes 101 penetrate through the side wall of the housing 100. The outlet ends of the plurality of nitrogen pipes 101 respectively penetrate into the interior of the housing 100 and extend obliquely downward, and are respectively aligned with each working area. The plurality of nitrogen pipes 101 are respectively used to connect to a nitrogen gas source.

[0050] It should be noted that a flow valve is connected to the nitrogen pipeline. During the actual working process, the amount of nitrogen gas sprayed into the working area can be adjusted by adjusting the opening degree of the flow valve, so as to form a good nitrogen gas protection environment during the microwave chip welding process, thereby reducing the oxidation rate of the solder at high temperature, ensuring sufficient wetting and full melting of the welding surface between the microwave chip and the metal carrier, and reducing the welding void ratio.

[0051] In this embodiment, please refer to Figure 1 , Figure 3 and Figure 4 . A nitrogen baffle ring 102 is provided on the inner wall of the top end of the housing 100. The density of nitrogen is lower than that of air, and it will slowly rise in the air after being heated. The nitrogen baffle ring 102 can block the rise of nitrogen, thereby delaying the diffusion speed of nitrogen and forming an effective nitrogen protection layer to ensure good anti-oxidation effect of the nitrogen protection layer during the eutectic welding process.

[0052] As a specific implementation manner of the embodiment of the present invention, please refer to Figure 1 , Figure 3 and Figure 4 . A sealing plate 302 is provided on the top surface of the working platform 300. When the metal carrier is placed on the working area corresponding to its size for operation, the sealing plate 302 is used to block the vacuum adsorption holes 301 in the remaining working areas. Only the vacuum adsorption holes 301 in the working area for welding operation can be connected to the vacuum pump pipeline 400 for adsorption work, and the remaining vacuum adsorption holes 301 are blocked by the sealing plate 302 to prevent the leakage of vacuum pressure from other vacuum adsorption holes 301, ensure the adsorption strength of the metal carrier, and at the same time can reduce the power loss of the vacuum pump and lower the operation cost.

[0053] In this embodiment, please refer to Figure 5 and Figure 7 . A fixed shaft 303 extending vertically upward is provided on the top surface of the working platform 300, and a plurality of working areas are spaced apart along the circumference of the fixed shaft 303. The sealing plate 302 is semi-circular or a sector with a central angle greater than 180°, and the sealing plate 302 is rotatably connected to the fixed shaft 303. By rotating the sealing plate 302, the working area that needs to be welded can be quickly exposed, while the remaining working areas are blocked, which is convenient to operate, can quickly switch the working areas, and is suitable for multi-variety welding operations of microwave chips.

[0054] In this embodiment, please refer to Figures 1 to 4 . A screw nut 304 is threadedly connected to the extending end of the fixed shaft 303, and a spring 305 is sleeved on the fixed shaft 303. One end of the spring 305 abuts against the top surface of the sealing plate 302, and the other end abuts against the bottom surface of the screw nut 304. By rotating the screw nut 304, the elastic force of the spring 305 can be adjusted. Through the elastic force of the spring 305, the sealing plate 302 can be tightly attached, so as to ensure the tight blockage of the vacuum adsorption holes 301 by the sealing plate 302 and avoid air leakage.

[0055] The present invention also provides a method for eutectic welding of microwave chips. Please refer to Figure 1 and Figure 8 . The method for eutectic welding of microwave chips includes the following steps:

[0056] Step S1: Power on and heat the working platform of the microwave chip eutectic soldering platform, with the heating temperature being 183 - 380°C, and turn on the vacuum pump.

[0057] Step S2: Vacuum adsorb the tinned board in the working area on the working platform that matches the size of the tinned board. Place solder on the tinned board for heating and melting, and then place the back of the microwave chip on the melted solder for friction tinning.

[0058] Step S3: Remove the microwave chip after tinning is completed for natural air cooling, and remove the tinned board.

[0059] Step S4: Place the metal carrier to be welded on the working platform 300, and vacuum adsorb the metal carrier through the vacuum adsorption holes 301 in the working area corresponding to the size of the metal carrier.

[0060] Step S5: Place solder on the top surface of the metal carrier for tinning. After tinning is completed, remove the metal carrier for natural air cooling.

[0061] Step S6: Place the tinned and air-cooled microwave chip at the corresponding position on the tinned and air-cooled metal carrier.

[0062] Step S7: Place the metal carrier with the microwave chip placed on it in the corresponding working area on the working platform 300, and vacuum adsorb it through the vacuum adsorption holes 301.

[0063] Step S8: After the solder layer on the top surface of the metal carrier and the bottom surface of the microwave chip is heated and melted, hold the microwave chip and perform circular friction on the metal carrier for 3 - 5 rounds or cross reciprocating friction for 3 - 5 times.

[0064] Step S9: Remove the metal carrier and the microwave chip with the molten solder layer from the microwave chip eutectic soldering platform, and let it cool naturally to complete the soldering.

[0065] It should be understood that the above steps S2 to S3 are the process of tinning the back of the microwave chip, and the above steps S4 to S5 are the process of tinning the front of the metal carrier. There is no strict sequence requirement between them, and it is also possible to tin the metal carrier first and then tin the microwave chip.

[0066] In addition, the solder used in the process of tinning the front of the metal carrier and the back of the microwave chip is all tin solder.

[0067] The eutectic soldering method for microwave chips provided by the present invention uses the above-mentioned eutectic soldering platform for microwave chips. There are multiple working areas on the working platform 300, and vacuum adsorption holes 301 suitable for adsorbing metal carriers of different sizes are respectively provided in the multiple working areas. Operators can select the corresponding working area according to the size of the metal carrier, so that the vacuum adsorption holes 301 in the working area adsorb and fix the metal carrier. The fixation of the metal carrier is simple, the operation is convenient, the adsorption is stable and reliable. Metal carriers of different sizes can select different working areas for adsorption and fixation, and the conversion of the fixation position is flexible and convenient. Especially for small-sized metal carriers, stable adsorption and fixation can be ensured. It can be applied to the manual friction eutectic soldering process of different models of microwave chips, with high versatility and is suitable for the eutectic soldering operation of multi-variety and small-batch microwave chips. It is of great significance especially for the popularization and application of MEMS circulators in the 5G communication field;

[0068] In addition, before the eutectic soldering of the microwave chips in the eutectic soldering method for microwave chips of the present invention, the bottom surface of the microwave chip and the top surface of the metal carrier are respectively subjected to a tinning process on the above-mentioned eutectic soldering platform for microwave chips, so that a good solder layer is formed on the bottom surface of the microwave chip and the top surface of the metal carrier after tinning. During soldering, only the solder on the bottom surface of the microwave chip and the top surface of the metal carrier needs to be heated and melted, and there is no need to add solder additionally. It can avoid the situation of high welding void ratio caused by poor cleanliness of the bottom surface of the microwave chip or the surface of the metal carrier, coating defects, or solder oxidation and other factors, thereby reducing the welding void ratio and improving the yield of the eutectic soldering operation of the microwave chips.

[0069] As a specific implementation manner of the eutectic soldering method for microwave chips provided by the present invention, the heating temperature of the working platform 300 matches the solder used when the bottom surface of the microwave chip and the top surface of the metal carrier are subjected to tinning treatment. For example, when tinning treatment is carried out using tin-lead solder, the heating temperature of the working platform 300 should be 183 - 200 °C to ensure that the solder can be heated and melted; when using tin-silver solder or tin-silver-copper solder, the heating temperature of the working platform 300 should be 220 - 240 °C to ensure that the solder can be heated and melted; when using gold-tin solder, the heating temperature of the working platform 300 should be 280 - 300 °C to ensure that the solder can be heated and melted; when using gold-germanium solder, the heating temperature of the working platform 300 should be 361 - 380 °C to ensure that the solder can be heated and melted.

[0070] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Microwave chip eutectic soldering platform, characterized in that, Comprising: A housing with an open top; A heating platform disposed inside the housing for electrical connection to an external power supply; A working platform disposed inside the housing, and the bottom surface thereof is in contact with the top surface of the heating platform; a plurality of working areas are provided on the top surface of the working platform, and the plurality of working areas are respectively used for placing metal carriers of different sizes; Wherein, a plurality of vacuum adsorption holes for communicating with a vacuum pump pipeline are respectively provided in the plurality of working areas, the vacuum adsorption holes are used for adsorbing the metal carriers, and the aperture of the vacuum adsorption holes in each of the working areas is proportional to the size of the placement surface of the metal carrier; a sealing plate is covered on the top surface of the working platform, and when the metal carrier is placed in the working area corresponding to its size for operation, the sealing plate is used to block the vacuum adsorption holes in the remaining working areas; A plurality of the vacuum adsorption holes are spaced apart in each of the working areas, and when the metal carrier is placed in the working area, at least two adjacent vacuum adsorption holes are located below the metal carrier; a plurality of ventilation holes are provided inside the working platform, and the plurality of ventilation holes correspond to the plurality of working areas one by one, and the plurality of ventilation holes are respectively used for communicating with the vacuum pump pipeline, and the vacuum adsorption holes extend downward from the top surface of the working platform and communicate with the corresponding ventilation holes; A fixing shaft extending vertically upward is provided on the top surface of the working platform, and the plurality of working areas are spaced apart along the circumference of the fixing shaft, the sealing plate is semi-circular or a sector with a central angle greater than 180°, and the sealing plate is rotatably connected to the fixing shaft.

2. The eutectic soldering platform for microwave chips according to claim 1, characterized in that: The ventilation holes extend radially along the side wall of the working platform, and the plurality of ventilation holes communicate with each other, and one of the ventilation holes is used for connecting the vacuum pump pipeline, and plug heads are respectively provided at the openings of the remaining ventilation holes.

3. The eutectic soldering platform for microwave chips according to claim 1, wherein: A plurality of nitrogen pipes penetrate through the side wall of the housing, and the outlet ends of the plurality of nitrogen pipes respectively penetrate into the interior of the housing and extend obliquely downward, and are respectively aligned with the respective working areas, and the plurality of nitrogen pipes are respectively used for connecting a nitrogen gas source.

4. The microwave chip eutectic welding platform according to claim 3, characterized in that: A nitrogen gas baffle ring is provided on the inner wall of the top end of the housing.

5. The eutectic soldering platform for microwave chips according to claim 1, wherein: A nut is threadedly connected to the extending end of the fixing shaft, a spring is sleeved on the fixing shaft, one end of the spring abuts against the top surface of the sealing plate, and the other end abuts against the bottom surface of the nut.

6. A eutectic soldering method for microwave chips, characterized in that Including the following steps: Power on and heat the working platform of the microwave chip eutectic soldering platform according to any one of claims 1-5, the heating temperature is 183-380 °C, and turn on the vacuum pump; Vacuum adsorb the tinned plate in the working area of the working platform that matches the size of the tinned plate, place solder on the tinned plate for heating and melting, and place the back surface of the microwave chip on the melted solder for friction tinning; Remove the microwave chip after tinning is completed for natural air cooling, and remove the tinned plate; Place the metal carrier to be welded on the working platform, and vacuum adsorb the metal carrier through the vacuum adsorption holes in the working area corresponding to the size of the metal carrier; Place solder on the top surface of the metal carrier for tinning. After tinning is completed, remove the metal carrier and let it air-cool naturally; Place the microwave chip after tinning and air-cooling at the corresponding position on the metal carrier after tinning and air-cooling; Place the metal carrier with the microwave chip placed thereon in the corresponding working area on the working platform, and perform vacuum adsorption through the vacuum adsorption holes; After the solder on the tinning layer on the top surface of the metal carrier and the bottom surface of the microwave chip is heated and melted, hold the microwave chip and perform circular friction on the metal carrier for 3 - 5 turns or cross reciprocating friction for 3 - 5 times; Remove the metal carrier and the microwave chip after the solder on the tinning layer is melted from the microwave chip eutectic welding platform, and let it cool naturally to complete the welding.

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