Brazing method of packaging shell and packaging shell

Abstract

The invention relates to the technical field of metal packaging shells, and discloses a packaging shell brazing method and a packaging shell thereof.The packaging shell brazing method comprises the following steps that sand blasting treatment is conducted on spare and accessory parts, the spare and accessory parts comprise a chassis and a connecting piece, chemical nickel plating and then nickel electroplating are conducted on the spare and accessory parts in sequence, and the chassis and the connecting piece are assembled through a T-shaped nested welding structure; the method comprises the steps that a base plate assembly is obtained, the base plate assembly is subjected to multi-section type heating brazing in a vacuum environment, and the packaging shell is manufactured. According to the method, welding of a nickel layer-solder-gold layer interface or a nickel layer-solder-nickel layer interface replaces a traditional gold layer-solder-gold layer welding interface; the same welding strength and sealing reliability requirements of a welding joint are met; according to the high-reliability packaging shell prepared through the method, the overall preparation technological process is obviously shortened, only nickel layers are plated on spare and accessory parts, gold plating is saved, and the plating finished product rate is obviously increased.

Description

Technical Field

[0001] The present invention relates to the technical field of metal packaging shells, in particular to a brazing method of a packaging shell and the packaging shell. Background Art

[0002] Eutectic Au80Sn20 brazing alloy (melting point 280°C) has been used in semiconductor and microelectronic packaging for many years. This eutectic gold-tin alloy solder possesses numerous superior properties, including a low melting point yet high strength, ensuring high reliability of solder joints; excellent thermal fatigue resistance, preventing fatigue fractures caused by temperature cycling, and durability under harsh climate conditions; excellent oxidation resistance, superior wetting and flowability, and high thermal conductivity. Precisely due to its excellent physical properties, gold-tin alloy has gradually become the preferred brazing material for optoelectronic device packaging.

[0003] Currently, in order to achieve good solder joint results with gold-tin alloy solder, in addition to reasonable brazing process settings, the general temperature is set at 310-350°C and the holding time is 5-10 minutes. There are certain requirements for the surface plating layer of the welded package shell, that is, the surfaces of both objects to be welded must be gold-plated. This method is invented by fully utilizing the brazing principle of gold-tin alloy solder. When the solder temperature reaches the eutectic point of 280°C, the solder melts and fully wets and flows on the gold-plated surface. At the same time, the gold layer on the surface of the welded parts will quickly melt into the gold-tin solder, followed by a reaction with the nickel layer to form an intermetallic compound (IMC layer) between gold, tin and nickel. This alloy layer is key to ensuring welding strength and sealing reliability. The gold plating on the surface of the shell welding part is to prevent oxidation of the nickel-plated surface, which will affect the wetting, spreading and reaction of the gold-tin solder at the welding joint, ultimately affecting the welding strength and sealing of the joint. The thickness of the gold layer of the shell is generally between 0.5μm and 1.5μm, which will significantly increase the manufacturing cost for packaging shells used in large-sized optoelectronic devices, generally with a length greater than 100mm and a width greater than 80mm.

[0004] In response to the market demand for continuously reducing the manufacturing cost of package shells, a currently popular practice is to adjust the large-sized metal chassis from being fully gold-plated to being partially gold-plated on the chassis, that is, only the partial surface of the brazing area is gold-plated. Although the partial gold plating process saves the cost of gold used in the manufacture of the shell, it places higher operational and control requirements on the plating process. It requires glue coating or custom fixtures to block the plating, which increases the number of steps and makes the operation complicated, prolonging the preparation process. At the same time, the complex plating process will inevitably reduce the yield of the shell chassis, and the overall average cost of the plating process is still more than 100 yuan. Therefore, for large-sized optoelectronic shells with large-sized chassis that are brazed with gold and tin using the partial gold plating process, the manufacturing cost of the shell base can be reduced to a limited extent. Summary of the Invention

[0005] The purpose of the present invention is to provide a brazing method for a package shell and the package shell thereof, so as to solve the problems in the prior art, significantly shorten the shell preparation process, reduce raw material costs, improve the yield rate, and have broad application prospects.

[0006] The present invention provides a method for soldering a package shell, comprising the following steps: sandblasting the parts, including the chassis and the connectors; The spare parts are sequentially subjected to chemical nickel plating and then electroplating nickel; Assemble the chassis and the connecting parts using a T-shaped nested welding structure to obtain a chassis assembly; The chassis assembly is subjected to multi-stage temperature-raising brazing in a vacuum environment to obtain a packaging shell.

[0007] In the present invention, chemical nickel plating is used as a base layer to first form a continuous and uniform nickel layer on the chassis, providing a complete conductive base for subsequent nickel electroplating. The subsequent nickel electroplating can uniformly thicken the nickel layer on this basis, avoiding local plating defects and ensuring the consistency of the overall plating of the shell. In the prior art, the chassis is only chemically nickel plated or electroplated with nickel, and the welding points between the chassis and the connectors are plated with nickel layers and gold layers in sequence. Professional tools need to be made for covering during the gold plating process, and the gold plating process is extremely cumbersome due to the special shape of the welding holes. The present invention simplifies this step, which not only reduces the process difficulty but also reduces the production cost of gold plating at the welding points.

[0008] In order to ensure airtightness, the traditional brazing method of the packaging shell can only be completed at the welding point of the chassis or on the gold layer-solder-connector gold layer of the entire chassis. The present invention changes the nickel plating method, controls the thickness of the nickel layer, and performs brazing in a multi-stage heating method under a vacuum environment. It can achieve brazing of the connector's gold layer-solder-chassis nickel layer interface, or the connector's nickel layer-solder-chassis nickel layer interface. The prepared packaging shell meets the sealing test requirements of Method 1014 of GJB548B-2005 "Microelectronic Device Test Methods and Procedures", can achieve good airtightness, and saves the gold plating process and gold plating cost. The manufacturing method of the present invention has low process cost and high yield in actual production.

[0009] In the above-described method for brazing a package housing, preferably, the parts are obtained by machining raw materials. The raw materials can be selected from materials commonly used in the art, such as Kovar or iron-nickel alloy. The machining method used is not particularly limited and can include, but is not limited to, milling, punching, wire cutting, and MIMU machining. It is understood that machining can be performed according to the designed dimensions, with a machining accuracy controlled within ±0.02 mm.

[0010] The brazing method of the package shell as described above, wherein preferably, the sandblasting method is: using 200-1000 mesh silicon carbide cutting sand at 0.5-1.0 kg / cm 2 The parts are polished under impact, and the roughness is controlled at 0.6-0.8 μm.

[0011] A method for brazing a package shell as described above, wherein preferably, the chemical nickel plating adopts a nickel-phosphorus alloy plating solution, the content of each component in the nickel-phosphorus alloy plating solution per liter is: 240g of nickel sulfate, 45g of nickel chloride, 3-8g of phosphorous acid, and the balance is deionized water, the phosphorus content of the plating layer ranges from 8 to 12%, the temperature is 85-95°C, the pH value is 4.4-4.8, and the thickness of the nickel layer after chemical nickel plating treatment is 2.54-5.08μm.

[0012] A method for brazing a package shell as described above, wherein preferably, the electroplating nickel adopts a sulfamate nickel plating solution, and the content of each component in the sulfamate nickel plating solution per liter is: 300-450g of nickel sulfamate, 5-15g of nickel chloride, 25-50g of boric acid, 0.1-1.0g of sodium dodecylsulfonate, and the balance is deionized water. The temperature is 44-54°C, the pH value is 4-5, and the thickness of the nickel layer after the electroplating nickel treatment is 2.54-5.08μm.

[0013] The purpose of using nickel sulfamate in the present invention is that the coating has low stress, which is conducive to relieving welding stress between parts made of different materials; the coating surface is dense, not easy to oxidize, and has good wettability and weldability.

[0014] A method for brazing a packaging shell as described above, wherein preferably, the T-shaped nested welding structure assembly method is specifically as follows: a welding hole is opened on the chassis before sandblasting, a stepped groove is cut on the side where the connector is connected to the chassis, the stepped groove is adapted to the size of the welding hole, solder is placed on the groove surface of the connector, and is positioned to the corresponding welding hole through a graphite mold. After assembly is completed, the single-side gap margin is 0.02~0.05mm.

[0015] The chassis of the traditional packaging shell has through holes for welding to the connectors, while the present invention adopts a T-shaped nested welding structure with a larger contact area and better welding effect. It takes into account the differences in thermal expansion coefficients between different materials and ensures the maximum capillary action capacity of the gap after assembly. The positioning of the graphite mold is a conventional process in this field. Its purpose is to position the chassis with the optical fiber tail tube and feed-through connector respectively, which will not be elaborated here.

[0016] In the above-mentioned method for brazing a package shell, preferably, the multi-stage temperature-raising brazing method is as follows: At vacuum degree <1.0×10 -3 Pa, first heating from room temperature to 200-250°C at a rate of 5-15°C / min, and keeping the temperature for 30-60 minutes to fully clean the brazing surfaces of the chassis assembly; Raise the temperature to 250-270°C at a rate of 2-5°C / min, and then keep warm for 5-10 minutes to fully preheat the chassis assembly; Rapidly heat the material to 380-400°C at a heating rate of 30-50°C / min, keep warm for 1-3 minutes, then rapidly cool it to 260-280°C at a cooling rate of 30-50°C / min, and finally cool it to room temperature at a cooling rate of 5-15°C / min to complete the brazing.

[0017] Gold-tin solder is used in the present invention. When conventionally brazing a package shell, the temperature is generally set at 310-350°C, and the holding time is 5-10 minutes. In the present invention, the temperature is quickly raised to the welding temperature of 400°C to increase the instantaneous superheat to enhance the wettability of the solder on the surface of the nickel layer. The holding time is shortened and the temperature is quickly lowered to allow the molten solder to solidify quickly, thereby avoiding excessive metallurgical reaction between the solder and the plating layer under high temperature conditions, thereby avoiding reduction in welding strength and sealing reliability.

[0018] The present invention also provides a packaging shell, which is manufactured using the above manufacturing method.

[0019] In the above-mentioned packaging housing, preferably, the connecting member includes an optical fiber pigtail and a feed-through connector, and corresponding welding holes are respectively provided on the chassis. The aperture of the welding hole is designed as follows: The welding hole at the optical fiber tail tube is according to the diameter D is used to open a hole, wherein D represents the diameter of the optical fiber tail tube; The welding holes at the feed-through connector are arranged according to the length ,width A hole is opened, where L represents the cross-sectional length of the feed-through connector and W represents the cross-sectional width of the feed-through connector.

[0020] The design of the welding hole not only meets the need for assembly clearance margin, but also makes use of the fact that the solder, after melting, fully adheres to the surface of the optical fiber tail tube or feed-through connector to wet and flow. Under the condition of capillary action, the solder fully flows and fills the fitting gap.

[0021] In the packaging shell as described above, preferably, the nickel layer surfaces of the optical fiber pigtail and the feed-through connector can also be plated with a gold layer. When the optical fiber pigtail and the feed-through connector are plated with a gold layer, the nickel layer thickness is 2.54μm~8.9μm, and the gold layer thickness is 0.5μm~1.5μm.

[0022] The present invention can achieve airtightness in the connection between the nickel layer, the solder and the nickel layer. However, in some cases, at the request of the client, the surface of the connector needs to be plated with a gold layer. Therefore, the connector in the present invention can also be plated with a gold layer after being plated with the nickel layer. When the gold layer needs to be plated again, the thickness of the nickel layer can be thinner.

[0023] Compared with the prior art, the present invention realizes the welding of nickel layer-solder-gold layer interface or nickel layer-solder-nickel layer interface instead of traditional gold layer-solder-gold layer welding interface, and achieves the same welding strength and sealing reliability requirements of the welded joint; the high-reliability packaging shell prepared by the present invention has a significantly shortened overall preparation process flow, and spare parts can be plated with only nickel layer, which saves gold plating and significantly improves the plating yield, reduces the overall manufacturing cost, and has good promotion and application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of a method for soldering a package shell provided by an embodiment of the present invention; Figure 2 1 is a schematic structural diagram of a package shell according to a method for soldering a package shell provided by an embodiment of the present invention; Figure 3 This is a schematic diagram of connecting an optical fiber pigtail in a brazing method of a package shell provided by an embodiment of the present invention; Figure 4 This is a connection diagram of a feed-through connector in a soldering method for a package shell provided by an embodiment of the present invention; Figure 5 This is a temperature curve diagram in step S4 of a method for soldering a package shell of the present invention.

[0025] Description of reference numerals: 1. Chassis; 2. Fiber optic tail tube; 3. Feed-through connector; 4. Solder hole; 40. Recess; 5. Groove; 6. Solder. DETAILED DESCRIPTION

[0026] The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0027] Example 1 See also Figure 2 As shown, the structure of the package housing manufactured in this embodiment includes components including a chassis 1, a fiber pigtail 2, and a feed-through connector 3. The chassis 1 is provided with welding holes 4 for connecting and assembling the fiber pigtail 2 and the feed-through connector 3. It should be noted that the package housing structure shown in this embodiment is only a specific example, and other conventional package housings in the art are also applicable.

[0028] Any range described in the present invention includes the end value and any numerical value between the end values ​​and any sub-range formed by the end value or any numerical value between the end values.

[0029] In this embodiment, a welding hole 4 is opened on the machined chassis 1. The cross-section of the welding hole 4 is stepped, one side is connected to the interior of the chassis 1, and the other side forms a recess 40 on the surface of the chassis 1. Stepped grooves 5 are cut on the surfaces where the optical fiber pigtail 2 and the feed-through connector 3 are connected to the chassis 1. The optical fiber pigtail 2 and the feed-through connector 3 are connected to the chassis 1 through the welding hole 4. The bottom wall of the groove 5 abuts against the recess 40 on the surface of the chassis 1. During brazing, solder 6 is first placed on the contact surface between the optical fiber pigtail 2 and the feed-through connector 3. The solder 6 uses Au80Sn20 eutectic alloy and is positioned to the corresponding welding hole 4 through a graphite mold. After assembly is completed, the single-side gap margin is 0.02~0.05mm.

[0030] In this embodiment, the aperture of the welding hole 4 is designed as follows: The welding hole 4 at the optical fiber tail tube 2 is D represents the diameter of the optical fiber tail tube 2. The welding hole 4 at the feed-through connector 3 is ,width A hole is opened, where L represents the cross-sectional length of the feed-through connector 3 and W represents the cross-sectional width of the feed-through connector 3 .

[0031] The method for manufacturing the package shell is as follows: Use 200-1000 mesh silicon carbide cutting sand at 0.5~1.0kg / cm 2 Polish the parts under impact, and control the roughness to 0.6~0.8μm; The parts are subjected to chemical nickel plating and then electroplating, wherein: The electroless nickel plating adopts a nickel-phosphorus alloy plating solution. The content of each component in the nickel-phosphorus alloy plating solution per liter is as follows: 240g of nickel sulfate, 45g of nickel chloride, 5g of phosphorous acid, and the balance of deionized water. The phosphorus content of the plating layer is within the range of 10%, the temperature is 90°C, the pH value is 4.6, and the thickness of the nickel layer after the electroless nickel plating treatment is 3.81μm. The nickel electroplating process uses a nickel sulfamate plating solution. The contents of each liter of the nickel sulfamate plating solution are as follows: 375 g of nickel sulfamate, 10 g of nickel chloride, 40 g of boric acid, 1 g of sodium dodecylsulfonate, and the balance of deionized water. The temperature is 49° C., the pH value is 4.5, and the thickness of the nickel layer after the nickel electroplating process is 3.81 μm. The overall thickness of the nickel plating layer after this step is 7.62 μm. The assembled chassis components were placed in a vacuum brazing furnace at a vacuum degree of 5.0×10 -4 Pa conditions, the temperature was raised from room temperature to 225°C at a heating rate of 10°C / min, and kept warm for 45 minutes to fully purify the brazing surfaces of the chassis components; the temperature was raised to 270°C at a heating rate of 35°C / min, and kept warm for 10 minutes to fully preheat the chassis components; the temperature was quickly raised to 400°C at a heating rate of 35°C / min, and kept warm for 2 minutes, and then the temperature was quickly lowered to 265°C at a cooling rate of 45°C / min, and finally cooled to room temperature at a cooling rate of 15°C / min to complete the brazing.

[0032] Figure 5 This is the temperature curve of the multi-stage heating brazing process of this embodiment, wherein T1 indicates that the temperature is increased to 225°C, t1 indicates that it is kept warm for 45 minutes, T2 indicates that the temperature is increased to 270°C, t2 indicates that it is kept warm for 10 minutes, T3 indicates that the temperature is quickly increased to 400°C, t3 indicates that it is kept warm for 2 minutes, and after t3, the temperature begins to drop rapidly to 265°C and finally drops to room temperature.

[0033] Example 2 The difference from Example 1 is that the optical fiber pigtail 2 and the feed-through connector 3 are plated with a nickel layer and then with a gold layer, the nickel layer has a thickness of 3.78 μm, and the gold layer has a thickness of 0.8 μm.

[0034] Example 3 The difference from Example 1 is that: The content of each component of the nickel-phosphorus alloy plating solution for chemical nickel plating is as follows: 240g nickel sulfate, 45g nickel chloride, 3g phosphorous acid, and the balance deionized water. The phosphorus content of the coating is within the range of 10%, the temperature is 85°C, the pH value is 4.5, and the thickness of the nickel layer after chemical nickel plating is 2.54μm. The content of each component in the nickel sulfamate plating solution per liter of nickel sulfamate is as follows: 300g nickel sulfamate, 5g nickel chloride, 30g boric acid, 0.5g sodium dodecylsulfonate, and the balance deionized water. The temperature is 46°C and the pH value is 4. The thickness of the nickel layer after the nickel electroplating treatment is 2.54μm, and the overall nickel layer thickness is 5.08μm. The assembled chassis components were placed in a vacuum brazing furnace at a vacuum degree of 6.0×10 -4 Pa conditions, first increase the temperature from room temperature to 200°C at a heating rate of 5°C / min, keep warm for 45 minutes, fully purify the brazing surfaces of the chassis components, increase the temperature to 250°C at a heating rate of 3°C / min, keep warm for 6 minutes, fully preheat the chassis components, quickly increase the temperature to 380°C at a heating rate of 30°C / min, keep warm for 1 minute, continue to quickly cool to 260°C at a cooling rate of 30°C / min, and finally cool to room temperature at a cooling rate of 5°C / min to complete the brazing.

[0035] Example 4 The difference from Example 1 is that: The content of each component in the nickel-phosphorus alloy plating solution for chemical nickel plating is as follows: 240g nickel sulfate, 45g nickel chloride, 5g phosphorous acid, and the balance deionized water. The phosphorus content of the coating is within the range of 8%, the temperature is 88°C, the pH value is 4.4, and the thickness of the nickel layer after chemical nickel plating is 3.52μm. The content of each component of the nickel sulfamate plating solution per liter of nickel sulfamate is: 410g nickel sulfamate, 12g nickel chloride, 38g boric acid, 0.1g sodium dodecylsulfonate, and the balance deionized water. The temperature is 44°C and the pH value is 5. The thickness of the nickel layer after the nickel electroplating treatment is 3.04μm, and the overall nickel layer thickness is 6.56μm. The assembled chassis components were placed in a vacuum brazing furnace at a vacuum degree of 3.0×10 -4 Pa conditions, first increase the temperature from room temperature to 220°C at a heating rate of 10°C / min, keep warm for 30 minutes, fully purify the brazing surfaces of the chassis components, increase the temperature to 255°C at a heating rate of 2°C / min, keep warm for 5 minutes, fully pre-prepare the chassis components, quickly increase the temperature to 385°C at a heating rate of 35°C / min, keep warm for 2 minutes, continue to quickly cool to 270°C at a cooling rate of 35°C / min, and finally cool to room temperature at a cooling rate of 12°C / min to complete the brazing.

[0036] Example 5 The difference from Example 1 is that: The content of each component in the nickel-phosphorus alloy plating solution for chemical nickel plating is as follows: 240g nickel sulfate, 45g nickel chloride, 8g phosphorous acid, and the balance deionized water. The phosphorus content of the coating is within the range of 12%, the temperature is 95°C, the pH value is 4.8, and the thickness of the nickel layer after chemical nickel plating is 5.08μm. The content of each component of the nickel sulfamate plating solution per liter of nickel sulfamate is: 450g nickel sulfamate, 15g nickel chloride, 50g boric acid, 1.0g sodium dodecylsulfonate, and the balance deionized water. The temperature is 54°C and the pH value is 5. The thickness of the nickel layer after the nickel electroplating treatment is 4.88μm, and the overall nickel layer thickness is 9.96μm. The assembled chassis components were placed in a vacuum brazing furnace at a vacuum degree of 8.0×10 -4 Pa conditions, first increase the temperature from room temperature to 250°C at a heating rate of 15°C / min, keep warm for 60 minutes, fully purify the brazing surfaces of the chassis components, increase the temperature to 270°C at a heating rate of 5°C / min, keep warm for 10 minutes, fully preheat the chassis components, quickly increase the temperature to 400°C at a heating rate of 50°C / min, keep warm for 3 minutes, continue to quickly cool to 280°C at a cooling rate of 50°C / min, and finally cool to room temperature at a cooling rate of 15°C / min to complete the brazing.

[0037] After testing, the packaging shells prepared in Examples 1 to 4 all meet the sealing test of GJB548B-2005 "Microelectronic Device Test Methods and Procedures" Method 1014. The following takes Example 1 as an example and combines it with a comparative example for explanation.

[0038] Comparative Example This comparative example is a local gold plating method commonly used in the prior art, and adopts the same implementation as Example 1, except that: the chassis 1 is subjected to only one of chemical nickel plating or electrolytic nickel plating, and the nickel plating layer has a thickness of 3 μm; the welding hole 4 is plated with a nickel layer and a gold layer in sequence, and the nickel plating layer has a thickness of 4 μm and the gold plating layer has a thickness of 1.0 μm; the optical fiber pigtail 2 and the feed-through connector 3 are plated with a nickel layer and a gold layer in sequence, and the nickel layer has a thickness of 5 μm and the gold layer has a thickness of 0.9 μm; and the brazing method in step S4 is soldering at 320° C. for 10 minutes; Five samples after brazing in Example 1, numbered 1-5, five samples after brazing in Example 2, numbered 6-10, and five samples in the comparative example, numbered 11-15, were randomly selected and tested for sealing properties according to Method 1014 of GJB548B-2005 "Test Methods and Procedures for Microelectronic Devices". The results are shown in the following table:

[0039] After testing, the air tightness of the 10 samples numbered 1-10 prepared by the present invention are all qualified, and the air tightness of each sample is less than 1.0×10 -8Pa.m 3 .s -1 , can achieve the same or even better airtight effect as the comparative example.

[0040] Further, samples No. 1-10 and comparative sample No. 11-15 were subjected to 100 cycles of temperature cycling from -65°C to +150°C and 15 cycles of thermal shock testing from -55°C to +125°C in accordance with the environmental test requirements of GJB2440A-2006 "General Specification for Hybrid Integrated Circuit Housings". The purpose was to test whether the encapsulated housings obtained by this method could still maintain good sealing after the shock test. After the test, the airtightness test was carried out in accordance with Method 1014 of GJB548B-2005 "Test Methods and Procedures for Microelectronic Devices". The results showed that the airtightness of the encapsulated housings was qualified, and the sealing performance was less than 1.0×10 -8 Pa.m 3 .s -1 , the results are shown in the following table:

[0041] Further, the weld strength tensile test of the feedthrough connector 3 and the optical fiber pigtail 2 was conducted on the sample numbers 1-10 and the comparative sample numbers 11-15 according to the method of GJB548B-2005 "Test Methods and Procedures for Microelectronic Devices". The results are shown in the following table:

[0042] From the comparison of the above tables, it can be seen that the present invention can still maintain excellent welding reliability when only nickel is plated on the chassis 1, the optical fiber pigtail 2, and the feed-through connector 3, or when nickel is plated on the chassis 1 and nickel and gold are plated on the optical fiber pigtail 2 and the feed-through connector 3, thereby greatly reducing the difficulty of local gold plating on a large and complex chassis 1.

[0043] By utilizing the brazing method and brazing structure of the present invention, a high-reliability package shell is realized. It only requires the chassis 1 to be primed with nickel and then electroplated with a layer of nickel sulfamate. There is no need to first nickel-plate the chassis 1 and then partially gold-plate it. This greatly reduces the difficulty of partial gold plating of a large-sized and complex chassis 1, is easy to operate, and is suitable for mass production.

[0044] The optical fiber tail tube 2 and feed-through connector 3 can be nickel-plated according to the method of the present invention, or continue to maintain a gold-plated surface according to customer needs, which can meet customer needs such as low-temperature soldering. The chassis 1 cavity only uses a nickel-plated surface to meet customer needs such as gluing. The present invention realizes the welding of the nickel layer-solder-gold layer interface and the nickel layer-solder-nickel layer interface instead of the traditional gold layer-solder-gold layer welding interface, saving the process steps of local gold plating, reducing the difficulty of gold plating, and saving gold plating costs. The present invention not only ensures the high reliability and low cost manufacturing requirements of the package shell, but also meets the micro-assembly requirements that traditional package shells must meet, significantly improves the plating yield rate, and significantly reduces the overall manufacturing cost, with good potential for promotion and application.

[0045] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings. The above is only a preferred embodiment of the present invention, but the scope of implementation of the present invention is not limited to what is shown in the drawings. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present invention.

Claims

1. A method for soldering a package shell, characterized in that: The steps include: sandblasting the parts, including the chassis and the connectors; The spare parts are sequentially subjected to chemical nickel plating and then electroplating nickel; Assemble the chassis and the connecting parts using a T-shaped nested welding structure to obtain a chassis assembly; The chassis assembly is subjected to multi-stage temperature-raising brazing in a vacuum environment to obtain a packaging shell.

2. The method for soldering a package shell according to claim 1, wherein: The spare parts are obtained by machining raw materials, wherein the machining accuracy is controlled within ±0.02mm.

3. The method for soldering a package shell according to claim 1, wherein: The sandblasting method is as follows: using 200-1000 mesh silicon carbide cutting sand at 0.5-1.0 kg / cm 2 The parts are polished under impact, and the roughness is controlled at 0.6-0.8 μm.

4. The method for soldering a package shell according to claim 1, wherein: The chemical nickel plating adopts a nickel-phosphorus alloy plating solution. The content of each component in the nickel-phosphorus alloy plating solution per liter is: 240g of nickel sulfate, 45g of nickel chloride, 3-8g of phosphorous acid, and the balance of deionized water. The phosphorus content of the plating layer ranges from 8 to 12%. The temperature is 85-95°C, the pH value is 4.4-4.8, and the thickness of the nickel layer after the chemical nickel plating treatment is 2.54-5.08μm.

5. The method for soldering a package shell according to claim 1, wherein: The nickel electroplating adopts a sulfamate nickel plating solution, wherein the contents of each component in the sulfamate nickel plating solution per liter are as follows: 300-450g of nickel sulfamate, 5-15g of nickel chloride, 25-50g of boric acid, 0.1-1.0g of sodium dodecylsulfonate, and the balance is deionized water. The temperature is 44-54°C, the pH value is 4-5, and the thickness of the nickel layer after the nickel electroplating treatment is 2.54-5.08μm.

6. The method for soldering a package shell according to claim 1, wherein: The assembly method of the T-shaped nested welding structure is specifically as follows: before sandblasting, a welding hole is opened on the chassis, a stepped groove is cut on the side where the connector is connected to the chassis, the stepped groove is adapted to the size of the welding hole, solder is placed on the groove surface of the connector, and is positioned to the corresponding welding hole through a graphite mold. After assembly is completed, the single-side clearance margin is 0.02~0.05mm.

7. The method for soldering a package shell according to claim 1, wherein: The method of the multi-stage temperature-raising brazing is as follows: At vacuum degree <1.0×10 -3 Pa, first heating the temperature from room temperature to 200-250°C at a rate of 5-15°C / min, and keeping the temperature for 30-60 minutes to fully clean the brazing surfaces of the chassis assembly; Raise the temperature to 250-270°C at a rate of 2-5°C / min, and then keep warm for 5-10 minutes to fully preheat the chassis assembly; Rapidly heat the material to 380-400°C at a heating rate of 30-50°C / min, keep warm for 1-3 minutes, then rapidly cool it to 260-280°C at a cooling rate of 30-50°C / min, and finally cool it to room temperature at a cooling rate of 5-15°C / min to complete the brazing.

8. A packaging shell, characterized in that: The invention discloses a method for preparing the invention.

9. The packaging shell according to claim 8, characterized in that The connector includes an optical fiber pigtail and a feed-through connector. Corresponding welding holes are respectively provided on the chassis. The aperture of the welding holes is designed as follows: The welding hole at the optical fiber tail tube is according to the diameter D is used to open a hole, wherein D represents the diameter of the optical fiber tail tube; The welding holes at the feed-through connector are arranged according to the length ,width A hole is opened, where L represents the cross-sectional length of the feed-through connector and W represents the cross-sectional width of the feed-through connector.

10. The packaging shell according to claim 8, wherein: The nickel layer surfaces of the optical fiber pigtail and the feed-through connector may be further plated with a gold layer. When the optical fiber pigtail and the feed-through connector are plated with a gold layer, the nickel layer thickness is 2.54 μm to 8.9 μm, and the gold layer thickness is 0.5 μm to 1.5 μm.

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