Metal packaging shell and processing method thereof

Abstract

The present invention belongs to the technical field of metal packaging shells, and specifically relates to a metal packaging shell and a processing method thereof. The present invention includes a component ring for installing leads and a chassis as a mounting base, characterized in that: a step hole is arranged at the chassis, and an extension ring is protruded along the axis of the component ring toward the component ring at the step surface of the step hole; the packaging shell also includes a transition ring clamped between the extension ring and the component ring, and a fixed fit is formed between the top ring surface of the transition ring and the bottom surface of the component ring, and a fixed fit is formed between the bottom ring surface of the transition ring and the top surface of the extension ring. The present invention can effectively improve or even avoid the welding stress problem between the component ring and the chassis, thereby effectively improving the performance and reliability of the metal packaging shell. Another object of the present invention is to provide a processing method based on the above-mentioned metal packaging shell, so as to concretize and facilitate the completion of its processing flow.

Description

Technical Field

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

[0002] With the development requirements of the electronic information industry, metal packaging shells are widely used in military and civilian fields such as communications, aviation, navigation, and weapons. In recent years, the development of optoelectronic conversion devices has been rapid, and the devices are increasingly moving towards integration such as light weight, miniaturization, fast heat dissipation, and low cost. Metal shells also have the same requirements. However, as kovar materials are widely used in high-reliability electronic packaging, when the component ring supported by kovar materials is welded to the chassis made of aluminum alloy, huge welding stress is often generated due to the material difference between the two, which affects the performance and reliability of the metal packaging shell, which needs to be solved urgently. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a metal packaging shell that can effectively improve or even avoid the welding stress problem between the component ring and the chassis, thereby effectively improving the performance and reliability of the metal packaging shell. Another purpose of the present invention is to provide a processing method based on the above-mentioned metal packaging shell, so as to concretize and facilitate its processing flow.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A metal packaging shell includes a component ring for installing leads and a chassis as a mounting base, characterized in that: a step hole is arranged at the chassis, and an extension ring is protruded along the axis of the component ring in the direction of the component ring at the step surface of the step hole; the packaging shell also includes a transition ring clamped between the extension ring and the component ring, a top ring surface of the transition ring and a bottom surface of the component ring form a fixed fit, and a bottom ring surface of the transition ring and a top surface of the extension ring form a fixed fit.

[0006] Preferably, the extension ring is in the shape of a closed ring coaxial with the step hole, the thickness of the transition ring is equal to the thickness of the extension ring, and the inner annular surface of the transition ring, the inner annular surface of the extension ring and the step hole wall where the step surface is located are on the same cylinder surface.

[0007] Preferably, the radial thickness of the extension ring and the transition ring is 0.3 mm to 0.4 mm, and the axial height of the extension ring and the transition ring is 2 to 3 times of their own thickness.

[0008] Preferably, the transition ring is made of oxygen-free copper.

[0009] Preferably, an outer flange and / or an inner flange is provided on the bottom annular surface of the transition ring to facilitate fitting with the extension ring.

[0010] Preferably, the component ring has a square plate shape, and an assembly hole for the lead wire to pass through is vertically penetrated at the plate surface of the component ring; the assembly hole and the lead wire are fixed to each other by an insulating medium.

[0011] Preferably, a processing method using the metal packaging shell is characterized by comprising the following steps:

[0012] 1) Processing the chassis by integrated milling:

[0013] 2) Electroplate the chassis, install sealing plugs at the step holes, and de-plating Au;

[0014] 3) The lead wire, insulating medium and component ring are sealed by high temperature melting to form a fused seal;

[0015] 4) Welding the sealing part and the transition ring with high-temperature silver-copper solder to form a lead assembly;

[0016] 5) Electroplating lead assembly;

[0017] 6) Place the electroplated lead assembly on the extension ring of the step hole of the chassis and form a finished product by welding with low-temperature gold-tin solder.

[0018] Preferably, the electroplating process includes degreasing, activation, Ni electroplating and full Au plating.

[0019] The beneficial effects of the present invention are:

[0020] 1) The design purpose of the present invention is to meet the requirements of light weight, miniaturization, fast heat dissipation and low cost of the device; in view of this, the present invention adopts a transition ring as an intermediate connector, which makes it possible to use a material with a thermal expansion coefficient close to that of the chassis and a lower hardness during actual operation, so that the stress conduction process from the chassis to the transition ring to the component ring will be smoother during welding, that is, there is no sudden change point, thereby effectively reducing the actual welding stress of the material. On the other hand, and more importantly, by convexly setting an extension ring in the direction of the component ring at the step surface of the step hole, the thin ring structure of the extension ring is utilized, so that a buffer ring area with a smaller thickness exists between the transition ring and the step hole. The formation of the buffer ring area can effectively buffer the stress of welding of different materials, greatly improve the sealing reliability of the present invention, and ensure the actual use performance of the metal shell. In particular, the thickness selection of 0.3mm to 0.4mm is based on the consideration that the greater the thickness, the greater the strength, but the buffer stress effect after welding will inevitably decrease. The above-mentioned specific thickness parameters can not only meet the processing operability and the strength requirements of the transition ring, but also achieve the optimal selection of buffer stress, with remarkable results.

[0021] In summary, the present invention can effectively improve or even avoid the welding stress problem between the component ring and the chassis, thereby effectively improving the performance and reliability of the metal packaging shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the assembly of the present invention;

[0023] Figure 2 is a schematic diagram of the three-dimensional structure of the chassis;

[0024] Figure 3 It is a schematic diagram of the three-dimensional structure of the sealing component;

[0025] Figure 4 It is a schematic diagram of the three-dimensional structure of the present invention.

[0026] The actual correspondence between the reference numerals and component names of the present invention is as follows:

[0027] 10-assembly ring 11-assembly hole

[0028] 20- chassis 21- step hole 21a- step surface 21b- extension ring 22- catheter hole

[0029] 30-transition ring 31-outer flange

[0030] 40-lead 50-insulating medium DETAILED DESCRIPTION

[0031] For ease of understanding, here we combine Figure 1-4 The specific structure and working mode of the present invention are further described as follows:

[0032] The specific structure of the present invention is as follows Figure 1-4 As shown, its main structure includes a chassis 20, a lead assembly and a conduit. The lead assembly is a brazed component formed by welding a sealing part and a transition ring 30 with a high-temperature solder, and a plurality of lead wires 40, a component ring 10, and an insulating medium 50 are sealed by high-temperature melting to form a sealing part; finally, the lead assembly, the conduit and the chassis 20 are welded by a low-temperature solder welding method. In actual operation, an assembly hole is opened on the component ring 10 to facilitate the installation of the lead wire 40; at the same time, a group of step holes 21 are opened on the chassis 20 for installing the component ring 10, a group of conduit holes 22 for installing the conduit, and four groups of flange holes are opened to fix the metal shell, and finally the packaging structure described in the present invention is formed.

[0033] In such Figure 2 In the structure shown, the chassis 20 is made of aluminum alloy, and the assembly ring 10 is made of calcite. Considering the material difference between the two, the present invention uses a transition ring 30 with a rib-shaped extension ring 21b to minimize and buffer stress. Figure 1As shown, the extension ring 21b is formed by axially extending from the step surface 21a at the step hole 21, so as to lift the assembly ring 10 away from the step surface 21a, so as to utilize the thin ring structure of the extension ring 21b to effectively buffer the welding stress, so as to achieve the purpose of ensuring the performance of the metal shell. The radial thickness of the extension ring 21b and the transition ring 30 is 0.3mm-0.4mm, and the axial height of the extension ring 21b and the transition ring 30 is 2-3 times of their own thickness. The extension ring 21b and the transition ring 30 of equal thickness, on the one hand, meet the actual welding strength; on the other hand, ensure the same plane of the inner ring surface, making it easier to position the mold internally during welding, avoiding the influence of the linear expansion coefficient caused by the different materials of the mold and the product, and improving the accuracy and precision of welding, achieving multiple goals at one stroke.

[0034] When selecting the material of the transition ring 30, oxygen-free copper having a thermal expansion coefficient close to that of aluminum alloy and a lower hardness is preferably used, which can further reduce and buffer stress, thereby greatly improving the airtight reliability of the present invention. Figure 1-2 As shown, the cross section of the transition ring 30 can be an "L"-shaped structure or a "⊥"-shaped structure, that is, the bottom ring surface of the transition ring 30 is arranged with an inner flange and / or an outer flange 31 to increase the welding area, thereby improving or even avoiding subsequent welding problems that may be caused by assembly errors. Since the chassis 20 is made of aluminum alloy, it can also achieve the effects of light weight, high strength and good heat dissipation.

[0035] In the actual research and development process, the comparison table of air tightness and failure ratio of using only transition ring, using step hole with transition ring, and using extension ring with transition ring is shown in Table 1 below:

[0036]

[0037] Table 1 Comparison of air tightness and failure ratio

[0038] As shown in Table 1, in the early stage of production, when the transition ring 30 was used alone, the failure rate of the component ranged from 4.5% to 6%. When the step hole 21 was developed in the middle stage to match the transition ring 30, the failure rate of the component was reduced to 0.4% to 0.7%. When the extension ring 21b of the present invention was used to match the transition ring, the failure rate of the first batch of tests was 0, which was very effective.

[0039] To facilitate further understanding of the present invention, the processing flow of the present invention is given as follows:

[0040] 1) Processing the chassis 20 by integrated milling:

[0041] 2) Electroplating the chassis 20 through the process of degreasing, activation, Ni electroplating, and full Au plating, installing sealing plugs at the conduit hole 22 and the step hole 21, and de-plating Au;

[0042] 3) The lead wire 40, the insulating medium 50 and the component ring 10 are sealed by high temperature melting to form a fused seal;

[0043] 4) Welding the sealing member and the transition ring 30 with high-temperature silver-copper solder to form a lead assembly;

[0044] 5) Electroplating the lead components through degreasing, activation, Ni electroplating, and full Au plating processes;

[0045] 6) Place the electroplated lead assembly on the extension ring 21b of the step hole 21 of the chassis 20, assemble the catheter at the catheter hole 22, and combine them by welding with low-temperature gold-tin solder to finally form the metal shell.

[0046] Of course, it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numerals in the claims should not be regarded as limiting the claims involved.

[0047] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0048] The techniques, shapes, and structural parts not described in detail in the present invention are all well-known techniques.

Claims

1. A metal packaging shell, comprising a component ring (10) for mounting leads and a chassis (20) as a mounting base, characterized in that: A step hole (21) is arranged on the chassis (20), and an extension ring (21b) is protruded on the step surface (21a) of the step hole (21) along the axis of the component ring (10) in the direction of the component ring (10); the packaging shell also includes a transition ring (30) sandwiched between the extension ring (21b) and the component ring (10), the top annular surface of the transition ring (30) and the bottom surface of the component ring (10) forming a fixed fit, and the bottom annular surface of the transition ring (30) and the top surface of the extension ring (21b) forming a fixed fit; The extension ring (21b) is in the shape of a closed ring coaxial with the step hole (21); the thickness of the transition ring (30) is equal to the thickness of the extension ring (21b); and the inner annular surface of the transition ring (30), the inner annular surface of the extension ring (21b) and the wall of the step hole (21) at the step surface (21a) are located on the same cylindrical surface.

2. The metal packaging shell according to claim 1, characterized in that: The thickness of the extension ring (21b) and the transition ring (30) in the radial direction is 0.3 mm to 0.4 mm, and the height of the extension ring (21b) and the transition ring (30) in the axial direction is 2 to 3 times their own thickness.

3. A metal packaging shell according to claim 1 or 2, characterized in that: The material of the transition ring (30) is oxygen-free copper.

4. A metal packaging shell according to claim 1 or 2, characterized in that: An outer flange (31) and / or an inner flange that facilitates fitting with the extension ring (21b) are provided on the bottom annular surface of the transition ring (30).

5. The metal packaging shell according to claim 1 or 2, characterized in that: The component ring (10) is in the shape of a square plate, and a mounting hole (11) for the lead wire (40) to pass through is vertically penetrated on the plate surface of the component ring (10); the mounting hole (11) and the lead wire (40) are fixed to each other via an insulating medium (50).

6. A method for processing the metal packaging shell according to claim 1 or 2, characterized in that The following steps are involved: 1) Processing the chassis (20) by integrated milling: 2) Electroplating the chassis (20), installing a sealing plug at the step hole (21), and stripping the Au; 3) The lead wire, the insulating medium and the component ring (10) are sealed by high temperature melting to form a fused seal; 4) welding the sealing member and the transition ring (30) by means of high-temperature silver-copper solder to form a lead assembly; 5) Electroplating lead assembly; 6) Placing the electroplated lead assembly on the extension ring (21b) of the step hole (21) of the chassis (20), and forming a finished product by welding with low-temperature gold-tin solder.

7. The processing method according to claim 6, characterized in that: The electroplating processes all include degreasing, activation, Ni electroplating and full Au plating.

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