Pipe base package shell for manned spacecraft simulation circuit and brazing process thereof

Abstract

The application relates to a tube base packaging shell for manned spacecraft simulation circuit and a brazing process thereof, and relates to the technical field of electronic packaging shells. The brazing process steps of the tube base packaging shell for manned spacecraft simulation circuit include surface polishing treatment, pre-oxidation treatment, fusion sealing treatment, brazing treatment and surface treatment. The specific temperature setting of the brazing treatment includes: temperature setting of 550-650 DEG C, time of 5 min; temperature setting of 700-760 DEG C, time of 15 min; temperature setting of 790-820 DEG C, time of 10 min; and temperature setting of 600-650 DEG C, time of 5 min. The preheating time during brazing is increased, the solder is uniformly distributed after direct cooling after brazing, the situation that the solder diffuses to the kovar frame base material is improved, the occurrence of welds and solder cavities is reduced, and the air tightness of the tube base packaging shell for manned spacecraft simulation circuit is improved.

Description

Technical Field

[0001] This application relates to the field of electronic packaging shell technology, and in particular to a socket packaging shell for analog circuits of manned spacecraft and its brazing process. Background Technology

[0002] Currently, electronic packaging enclosures are widely used in industrial fields with high reliability requirements, such as aerospace and aviation. Maintaining the stability of the components packaged within these enclosures throughout the product's lifespan is crucial, which places high demands on the component packaging process steps, process parameters, and process experience. For high-power device packaging enclosures with a power dissipation density greater than 51W / in², the base plate material is generally selected from materials such as tungsten copper or oxygen-free copper. These enclosures are typically brazed to frames made of Kovar alloy, steel, etc., to create a fully sealed structure.

[0003] When brazing the package shell composed of Kovar alloy and tungsten copper, the preheating time is short and the holding time after the solder melts is long, which has a significant impact on the flow of solder. This can cause serious solder diffusion into the Kovar alloy base material, resulting in less solder to fill the gaps and making it easy to produce weld seams, solder voids, and other problems.

[0004] The aforementioned solder diffusion can also be removed using a special silver stripping liquid, but there are risks such as metal corrosion during the silver stripping process and solder loss if the silver stripping time is not properly controlled, which can affect the reliability of the casing.

[0005] Regarding the aforementioned technologies, the inventors believe that the encapsulation shell welding process is prone to phenomena such as weld seams and solder voids, resulting in poor airtightness of the encapsulation shell. Summary of the Invention

[0006] In order to improve the problem of weld seams and solder voids that are easily generated in the welding process of the packaging shell, this application provides a tube socket packaging shell for manned spacecraft analog circuit and its brazing process.

[0007] In a first aspect, this application provides a brazing process for a socket package housing for analog circuits of a manned spacecraft, employing the following technical solution: Surface polishing treatment of the frame: Take an appropriate amount of chemical polishing solution, place the entire frame in the chemical polishing solution, and take it out when the surface of the frame gradually becomes bright. Rinse the frame with clean water. The frame is pre-oxidized: the frame and the fine lead are wet-nitrogen oxidized until the surface of the frame and the fine lead is uniformly mouse gray. The frame is assembled with a glass preform and the fine lead wire, and the assembled frame is placed in a sintering furnace for fusion sealing. The ceramic component, the frame, and the tungsten copper base plate are assembled onto a tooling fixture, and brazed together using the same temperature and time; the specific brazing temperature is set as follows: For the first preheating, set the temperature to 550–650℃ and the time to 5 minutes; The second preheating is set at 700-760℃ for 15 minutes. Brazing treatment, temperature set at 790~820℃, time 10min; Cooling treatment: temperature set to 600–650℃, time set to 5 minutes; The surface of the housing of the manned spacecraft analog circuit is treated.

[0008] By adopting the above technical solution, the first and second temperature zones provide sufficient preheating time for the solder, allowing its chemical composition to gradually transform into a molten state. In the third temperature zone, the solder is heated, transforming into a molten to liquid state. The molten solder then chemically reacts with the Kovar frame during capillary filling. The fourth temperature zone does not increase the temperature; the previous temperature zone circulates with the furnace belt, allowing the solder to cool directly after welding until it completely solidifies. This significantly improves the diffusion of solder onto the Kovar frame base material, reduces weld seams and solder voids, and enhances the airtightness of the casing for the manned spacecraft analog circuit socket.

[0009] Optionally, the sealing temperature is 950–980°C.

[0010] By adopting the above technical solution, the glass, fine lead wire and Kovar alloy frame have a better sealing effect within the temperature range of 950-980℃.

[0011] Optionally, the brazing is performed using AgCu28 solder.

[0012] By adopting the above technical solution, AgCu28 solder has good thermal conductivity and low resistivity. AgCu28 solder can effectively connect oxygen-free copper, Kovar alloy and ceramic materials. Using AgCu28 solder makes the tube socket package of the brazed manned spacecraft simulation circuit have good airtightness.

[0013] Optionally, the surface treatment includes: The casing of the manned spacecraft's analog circuit was sandblasted using glass beads. Nickel plating is applied to the surface of the housing of the manned spacecraft analog circuit using multi-waveform current.

[0014] Optionally, the ceramic assembly includes a ceramic insulator, a gasket, and an oxygen-free copper lead. Before the brazing, the ceramic assembly is assembled and pre-brazing is performed.

[0015] By adopting the above technical solutions, the glass bead spraying method can better remove surface impurities from the casing of the manned spacecraft simulation circuit socket after brazing. Using multi-waveform current to nickel-plate the surface of the casing can significantly improve the plating quality, enhance its salt spray resistance, and meet the subsequent requirements for capping and bonding.

[0016] By adopting the above technical solution, the beneficial effects of the brazing process for the casing of the manned spacecraft analog circuit provided in this application are: increasing the preheating time during brazing, and cooling directly after brazing to make the solder distribution uniform, improving the situation of solder diffusion to the Kovar frame base material, reducing the occurrence of weld seams and solder voids, and improving the airtightness of the casing of the manned spacecraft analog circuit.

[0017] Secondly, the tube socket package shell for manned spacecraft simulation circuit provided in this application adopts the following technical solution: the tube socket package shell for manned spacecraft simulation circuit is manufactured using the above-mentioned brazing process for the tube socket package shell for manned spacecraft simulation circuit.

[0018] Optionally, the housing for the manned spacecraft analog circuitry includes: Base plate; A frame is attached to the base plate by brazing. The frame has a first set of through holes and a second set of through holes on its two sides. The diameters of the first set of through holes and the second set of through holes are different. A ceramic component, comprising a ceramic insulator and an oxygen-free copper lead wire, wherein the ceramic insulator is brazed to the inside of the first set of through holes, and the oxygen-free copper lead wire is inserted inside the ceramic insulator; A glass assembly, comprising a glass insulator and a fine lead wire, wherein the glass insulator is disposed inside the second set of through holes, and the fine lead wire is inserted through the glass insulator.

[0019] Optionally, the frame has an annular groove on the side where the first set of through holes are opened.

[0020] Optionally, the ceramic assembly further includes a gasket disposed on the side of the ceramic insulator away from the glass insulator.

[0021] Optionally, the ceramic insulator protrudes from the frame on both sides, while the glass insulator is aligned with both sides of the frame.

[0022] By adopting the above technical solution, the beneficial effects of the tube socket enclosure for manned spacecraft simulation circuit provided in this application are as follows: the frame adopts the form of side-out bent pins, and ceramic insulators and glass insulators are respectively set on both sides of the frame. Oxygen-free copper leads are passed through the ceramic insulators, and thin leads are passed through the glass insulators. The two different sets of insulators and leads enable the tube socket enclosure for manned spacecraft simulation circuit to adapt to a variety of different environments and meet a variety of connection requirements.

[0023] In summary, the brazing process for the socket package housing of a manned spacecraft analog circuit provided in this application has at least the following beneficial technical effects: 1. The preheating time during brazing has been increased, and cooling is performed directly after brazing to ensure uniform solder distribution. This improves the situation where solder diffuses onto the Kovar frame base material, reduces the occurrence of weld seams and solder voids, and improves the airtightness of the casing shell for the manned spacecraft analog circuit.

[0024] 2. Using a glass bead spraying method can better remove surface impurities from the casing of the manned spacecraft simulation circuit's socket package after brazing. Using multi-waveform current to nickel-plate the surface of the casing can significantly improve plating quality, enhance its salt spray resistance, and meet the requirements for subsequent capping and bonding. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of the soldering process for the casing of the manned spacecraft simulation circuit in Example 1.

[0026] Figure 2 This is a schematic diagram of the casing of the manned spacecraft simulation circuit in Example 2.

[0027] Figure 3 yes Figure 2 A magnified diagram of a partial explosion.

[0028] Figure 4 yes Figure 2 Top view of the housing of the tube socket used for the analog circuit of the manned spacecraft.

[0029] Explanation of reference numerals in the attached drawings: 10, housing for manned spacecraft simulation circuit; 100, base plate; 110, mounting hole; 200, frame; 210, first set of through holes; 211, ceramic insulator; 212, gasket; 213, oxygen-free copper lead; 220, glass insulator; 221, thin lead. Detailed Implementation

[0030] Example 1 Embodiment 1 of this application discloses a brazing process for a socket package 10 for a manned spacecraft analog circuit, referring to... Figure 1 The steps include: surface polishing, pre-oxidation, fusion sealing, brazing, and surface treatment.

[0031] Take an appropriate amount of chemical polishing solution, place the frame 200 entirely in the solution, and agitate it to ensure a thorough reaction. Once the surface of the frame 200 gradually becomes shiny, remove it and rinse it thoroughly with clean water. Surface polishing of the Kovar alloy frame 200 removes impurities and smooths the surface. Immersing a batch of frames 200 entirely in the chemical polishing solution offers higher production efficiency compared to traditional methods using files to remove impurities.

[0032] Pre-oxidation treatment of frame 200: Frame 200 and fine lead wire 221 are subjected to wet nitrogen oxidation until the surfaces of frame 200 and fine lead wire 221 are uniformly mouse gray. Frame 200 after chemical polishing needs to undergo pre-oxidation treatment as soon as possible. If pre-oxidation treatment of frame 200 cannot be performed in time, the chemically polished frame 200 should be stored under vacuum.

[0033] The oxidized frame 200 is assembled with glass blanks and pre-oxidized fine leads 221: First, the glass blank is placed into the mounting holes of the pre-set glass insulators 220 in the frame 200, and then the fine leads 221 are inserted into the glass blank. After completing the above assembly operation for each mounting hole of the glass insulators 220 in the frame 200, the assembled frame 200 is placed in a sintering furnace for sealing at a temperature of 950–980°C.

[0034] Before assembling the frame 200 with the glass preform and the fine lead 221, the fine lead 221 needs to be bent, and the BH series glass powder is placed in a sintering mold and sintered into a glass preform. The BH series glass powder can also be replaced with other glass powders, as long as they meet the strength requirements of the encapsulated glass insulator 220.

[0035] Assemble the ceramic components, frame 200, and tungsten copper base plate 100 to be brazed onto the tooling fixture, place AgCu28 solder at the position to be brazed, and braze the ceramic components, frame 200, and tungsten copper base plate 100 using the same temperature and time.

[0036] The specific temperature for brazing is set as follows: For the first preheating, set the temperature to 550–650℃ and the time to 5 minutes; The second preheating is set at 700-760℃ for 15 minutes. Brazing treatment, temperature set at 790~820℃, time 10min; Cooling treatment: temperature set to 600-650℃, time set to 5 minutes.

[0037] The first and second preheating processes provide sufficient preheating time for the AgCu28 solder, allowing its chemical composition to gradually transition to a molten state. During brazing, the temperature reaches the melting point of the AgCu28 solder, transforming it into a molten to liquid state. The molten AgCu28 solder then chemically reacts with the Kovar frame 200 during the capillary filling process. During cooling, the temperature is not increased; the preheating zone circulates with the furnace belt, allowing the AgCu28 solder to cool directly after welding until it completely solidifies. This significantly improves the diffusion of solder onto the Kovar frame 200 base material.

[0038] The brazing uses AgCu28 solder, which has good thermal conductivity and low resistivity. AgCu28 solder can effectively connect oxygen-free copper, Kovar alloy and ceramic materials. The use of AgCu28 solder makes the tube socket package 10 of the brazed manned spacecraft simulation circuit have good airtightness.

[0039] During the brazing process of the manned spacecraft simulation circuit socket package 10, oxides and dirt easily appear on its surface. These substances can seriously affect the performance and lifespan of the manned spacecraft simulation circuit socket package 10. Therefore, surface treatment is required for the brazed manned spacecraft simulation circuit socket package 10. Surface treatment includes sandblasting and nickel plating. Generally, sandblasting is performed first, followed by nickel plating. First, imported glass beads are used to sandblast the manned spacecraft simulation circuit socket package 10 to achieve a uniform surface appearance. Appropriate glass beads are selected according to actual needs. Fully automatic or semi-automatic sandblasting equipment can be used to sandblast the manned spacecraft simulation circuit socket package 10 to improve production efficiency. Sandblasting the brazed manned spacecraft simulation circuit socket package 10 can reduce impurities on its surface.

[0040] Nickel plating is performed on the surface of the housing 10 for the manned spacecraft analog circuit using multi-waveform current. Using multi-waveform current can greatly improve the plating quality, enhance the salt spray resistance, and meet the subsequent sealing and bonding requirements of the housing 10 for the manned spacecraft analog circuit.

[0041] The ceramic assembly includes a ceramic insulator 211, a gasket 212, and an oxygen-free copper lead 213. Before brazing, the ceramic assembly is assembled by bending the oxygen-free copper lead 213 and inserting it into the ceramic insulator 211. The gasket 212 is then installed in the ceramic insulator 211 near the center of the oxygen-free copper lead 213. AgCu28 solder is then placed in the gaps between the ceramic insulator 211, the lead, and the gasket 212 to perform pre-brazing of the ceramic assembly. This pre-brazing process allows for the brazing of the manned spacecraft simulation circuit's 10-module housing using a socket package, reducing brazing difficulty and improving production efficiency.

[0042] The principle of the brazing process of the manned spacecraft simulation circuit socket package shell 10 provided in this application embodiment is as follows: the preheating time during brazing is increased, and the cooling is carried out directly after brazing to make the solder distribution uniform, which improves the situation of solder diffusion to Kovar frame 200 base material, reduces the occurrence of weld seams and solder voids, and improves the airtightness of the manned spacecraft simulation circuit socket package shell 10.

[0043] Example 2 Embodiment 2 of this application provides a socket package 10 for a manned spacecraft simulation circuit, which is manufactured using the brazing process disclosed in the embodiment.

[0044] Reference Figure 2 , Figure 3 , Figure 4 A housing 10 for a manned spacecraft analog circuit includes a base plate 100, a frame 200, a ceramic component, and a glass component.

[0045] The base plate 100 is made of oxygen-free copper and is generally rectangular. One side of the base plate 100 has a flange for placing solder. The base plate 100 can be manufactured by casting or cutting. Mounting holes 110 extend from the four corners of the base plate 100. The mounting holes 110 are used to assemble the manned spacecraft analog circuit socket housing 10 with other devices.

[0046] The frame 200 is made of Kovar material and is directly mounted on the base plate 100 via brazing. The frame 200 is a square frame with openings on both sides. A first set of through holes 210 and a second set of through holes are respectively opened on both sides of the frame 200. The diameters of the first set of through holes 210 and the second set of through holes are different. The first set of through holes 210 is used to install ceramic components, and the second set of through holes is used to install glass components. An annular groove is provided on the side of the frame 200 where the first set of through holes 210 are located. The annular groove facilitates the installation of ceramic components.

[0047] Reference Figure 3 The ceramic assembly includes a ceramic insulator 211, a gasket 212, and an oxygen-free copper lead 213. The ceramic insulator 211 is located inside the first set of through holes 210, and both sides of the ceramic insulator 211 protrude from the frame 200. The oxygen-free copper lead 213 passes through the ceramic insulator 211, and the gasket 212 is installed on the ceramic insulator 211 away from the glass insulator 220. The oxygen-free copper lead 213 has good conductivity and low resistivity. Using the oxygen-free copper lead 213 can increase the current carrying capacity of the housing 10 for the manned spacecraft analog circuit socket, making it suitable for connection with high-power devices. The expansion coefficients of oxygen-free copper and ceramics differ significantly, which will generate large sealing stress during brazing. The design of the gasket 212 can reduce the sealing stress during brazing of the ceramic insulator 211 and the oxygen-free copper lead 213, preventing the ceramic from cracking during the brazing process.

[0048] Reference Figure 2 , Figure 4The glass assembly includes a glass insulator 220 and a thin lead 221. The glass insulator 220 is located inside the second set of through holes, and its two sides are aligned with the frame 200. The thin lead 221 passes through the glass insulator 220, and one end of the thin lead 221 inside the frame 200 is crimped. The thin lead 221 has a low current carrying capacity and is suitable for connecting to low-power devices.

[0049] When manufacturing the housing 10 for the manned spacecraft analog circuit, the frame 200 is first polished, the fine leads 221 and the frame 200 are pre-oxidized, the fine leads 221, the glass preform and the frame 200 are assembled, and the fine leads 221, the glass preform and the frame 200 are fused together.

[0050] Place AgCu28 solder on the flanged side of the base plate 100, assemble the frame 200 onto the base plate 100, place AgCu28 solder into the first set of through holes 210, assemble the ceramic component, base plate 100, and frame 200 onto the tooling fixture, and braze the ceramic component, base plate 100, and frame 200.

[0051] The specific temperature setting for brazing is as follows: For the first preheating, set the temperature to 550–650℃ and the time to 5 minutes; The second preheating is set at 700-760℃ for 15 minutes. Brazing treatment, temperature set at 790~820℃, time 10min; Cooling treatment: temperature set to 600-650℃, time set to 5 minutes.

[0052] After brazing, the casing 10 of the manned spacecraft simulation circuit is surface treated.

[0053] The implementation principle of the manned spacecraft simulation circuit socket housing 10 provided in Embodiment 2 of this application is as follows: the frame 200 adopts the form of side-out bent pins, and ceramic insulators 211 and glass insulators 220 are respectively arranged on both sides of the frame 200. Oxygen-free copper leads 213 are passed through the ceramic insulators 211, and thin leads 221 are passed through the glass insulators 220. The two sets of different insulators and leads enable the manned spacecraft simulation circuit socket housing 10 to adapt to a variety of different environments and meet a variety of connection requirements.

[0054] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A brazing process for a socket package housing for a manned spacecraft analog circuit, characterized in that, The steps include: Surface polishing treatment of the frame: Take an appropriate amount of chemical polishing solution, place the entire frame in the chemical polishing solution, and take it out when the surface of the frame gradually becomes bright. Rinse the frame with clean water. The frame is pre-oxidized: the frame and the fine lead are wet-nitrogen oxidized until the surface of the frame and the fine lead is uniformly mouse gray. The frame is assembled with a glass preform and the fine lead wire. The assembled frame is then placed in a sintering furnace for sealing. The sealing temperature is 950-980°C. The ceramic component, the frame, and the tungsten copper base plate are assembled onto a tooling fixture. The ceramic component, the frame, and the tungsten copper base plate are then brazed using the same temperature and time, with AgCu28 solder used for the brazing. The specific brazing temperature is set as follows: For the first preheating, set the temperature to 550–650℃ and the time to 5 minutes; The second preheating is set at 700-760℃ for 15 minutes. Brazing treatment, temperature set at 790~820℃, time 10min; Cooling treatment: temperature set to 600–650℃, time set to 5 minutes; The surface treatment of the housing of the manned spacecraft simulation circuit is performed; the surface treatment includes: sandblasting the housing of the manned spacecraft simulation circuit with glass beads; and nickel plating the surface of the housing of the manned spacecraft simulation circuit with multi-waveform current. The ceramic component includes a ceramic insulator, a gasket, and an oxygen-free copper lead. Before the brazing, the ceramic component is assembled and pre-brazing is performed.

2. A socket package housing for a manned spacecraft analog circuit, characterized in that, It is manufactured using the brazing process of the manned spacecraft analog circuit socket package housing as described in claim 1; include: Base plate; A frame is attached to the base plate by brazing. The frame has a first set of through holes and a second set of through holes on its two sides. The diameters of the first set of through holes and the second set of through holes are different. A ceramic component, comprising a ceramic insulator and an oxygen-free copper lead wire, wherein the ceramic insulator is brazed to the inside of the first set of through holes, and the oxygen-free copper lead wire is inserted inside the ceramic insulator; A glass assembly, comprising a glass insulator and a fine lead wire, wherein the glass insulator is disposed inside the second set of through holes and the fine lead wire is inserted inside the glass insulator; The frame has an annular groove on the side where the first set of through holes are opened; The ceramic component also includes a gasket disposed on the side of the ceramic insulator away from the glass insulator; The ceramic insulator protrudes from the frame on both sides, while the glass insulator is aligned with both sides of the frame.

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