Parallel seam welding structure for large-size ceramic packaging

Abstract

The utility model provides a parallel seam welding structure of a large-size ceramic package, which comprises a ceramic shell, a metal welding frame and a cover plate, the metal welding frame is welded on the ceramic shell, and the cover plate is welded on the metal welding frame. The cover plate is provided with an edge thin part and a central area is provided with a thickening part, the metal welding frame is sequentially provided with a first supporting part and a second supporting part from top to bottom, and the width of the second supporting part is larger than 0.2 mm; the edge thin part of the cover plate is contacted with the surface of the first supporting part, the bottom surface of the thickening part in the central area of the cover plate is partially contacted with the surface of the second supporting part, or a gap is arranged between the bottom surface of the thickening part and the surface of the second supporting part. According to the utility model, the metal welding frame is designed into a structure with two supporting parts, so that the thin part and the thickened part at the edge of the large-size ceramic packaging cover plate are effectively supported, the deformation resistance of the cover plate is enhanced, and the reliability and the appearance of a circuit are ensured.

Description

Technical Field

[0001] The utility model belongs to the technical field of semiconductor packaging, and particularly relates to a parallel seam welding structure of a large-size ceramic package. Background Art

[0002] The common sealing methods for ceramic packaging are alloy sealing and parallel seam welding (abbreviated as flat seam).

[0003] Alloy sealing uses gold-tin solder to weld the shell and cover together. The process temperature is high, and the devices in the entire package will experience the high temperature during sealing; while parallel seam welding passes a large current in the sealing area, generating local high temperature through the contact resistance between the cover and the metal welding frame of the shell, achieving welding of the cover and the ceramic shell, and the devices in the package will not be affected by the high temperature. For the above reasons, the parallel seam welding process is widely used in ceramic packaging, especially in system-level packaging containing high-temperature-resistant devices such as resistors and capacitors.

[0004] Common small size ceramic package parallel seam welding sealing structure such as Figure 1 As shown, the cover plate 1, the metal welding frame 2 and the ceramic shell 3, the cover plate 1 is usually a flat plate structure, and the thickness of the cover plate 1 is usually about 0.1mm. Since the cover plate 1 is relatively thin, when the size of the cover plate 1 increases, the cover plate will produce a large deformation under the conditions of internal and external forces (such as constant acceleration test, external pressure of leak test after sealing, pressure of test fixture during circuit test, etc.), affecting the appearance of the circuit, and even causing the cover plate to contact with the internal circuit, resulting in failure of the derived circuit. Therefore, when the size of the cover plate 1 increases, more use is made of Figure 2 The structure shown is that the middle area of ​​the cover is thickened to reduce the deformation of the circuit when subjected to external force. However, due to welding requirements, the thickness of the part of the cover that contacts the metal welding frame is still relatively thin.

[0005] However, although the thickness of the cover plate can be increased to 2-4 times, it cannot achieve the deformation resistance of a thick cover plate under full support conditions. This is because the weak point of the cover plate with this structure is transferred to the junction of the thick and thin cover plates; in many scenarios, the junction will first show signs of plastic deformation caused by large deformation of the cover plate, and it cannot be restored, affecting the reliability and appearance of the circuit.

[0006] Therefore, for large-sized parallel seam welding structures, a more optimized structure is needed to further improve the strength of the cover plate and reduce the deformation of the cover plate under external force conditions. Summary of the invention

[0007] The purpose of the utility model is to provide a parallel seam welding structure for a large-size ceramic package; by designing a metal welding frame as a structure with two supporting parts, effective support is provided for both the thin edge part and the thickened part of the cover plate of the large-size ceramic package, thereby enhancing the ability of the cover plate to resist deformation and ensuring the reliability and appearance of the circuit.

[0008] To achieve the above-mentioned purpose, the utility model provides a parallel seam welding structure of a large-size ceramic package, which includes a ceramic shell, a metal welding frame and a cover plate, wherein the metal welding frame is welded to the ceramic shell, and the cover plate is welded to the metal welding frame. The cover plate is provided with a thin edge portion and a thickened portion in the center area, and the metal welding frame has a first support portion and a second support portion from top to bottom, and the width of the second support portion is greater than 0.2 mm; the thin edge portion of the cover plate contacts the surface of the first support portion, and the bottom surface of the thickened portion in the center area of ​​the cover plate contacts the surface of the second support portion, or a gap is set between the bottom surface of the thickened portion and the surface of the second support portion.

[0009] In some embodiments, the distance between the surface of the second support portion and the surface of the first support portion is greater than or equal to the height of the thickened portion in the central area of ​​the cover plate.

[0010] In some embodiments, the width of the metal weld frame is greater than 0.5 mm.

[0011] In some embodiments, the metal welding frame is integrally formed. The structure of the metal welding frame is simple and can be realized by mechanical processing or chemical etching without complicated processes.

[0012] In some embodiments, the gap between the bottom surface of the thickened portion and the surface of the second supporting portion is less than 40 μm.

[0013] Compared with the prior art, the utility model has the following beneficial effects:

[0014] 1. The utility model designs the metal welding frame into a structure with two supporting parts to effectively support the thin edge part and the thickened part of the cover plate of the large-size ceramic package, thereby enhancing the ability of the cover plate to resist deformation and ensuring the reliability and appearance of the circuit;

[0015] 2. When the bottom edge of the thickened portion in the center area of ​​the cover plate directly contacts the surface of the second support portion, the second support portion directly provides effective support to the cover plate to prevent deformation of the cover plate;

[0016] 3. A gap may also be provided between the bottom surface of the thickened portion in the center area of ​​the cover plate and the surface of the second support portion, allowing the cover plate to deform to a certain extent. When deformed to a certain extent, the thickened portion of the cover plate contacts the second support portion of the metal welding frame, thereby avoiding further deformation of the cover plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a small-sized parallel seam welding sealing structure in the prior art is shown;

[0018] Figure 2 The schematic diagram of the structure of a large-size parallel seam welding sealing structure in the prior art is shown;

[0019] Figure 3 A schematic diagram showing the structure of Embodiment 1 of the present invention is shown;

[0020] Figure 4 The structural schematic diagram of the cover plate in the present invention is shown;

[0021] Figure 5 A schematic structural diagram of embodiment 2 of the present invention is shown. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention more clear, the technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0023] Example 1

[0024] The parallel seam welding structure of the large-size ceramic package provided in this embodiment is as follows Figure 3 As shown, it includes a ceramic housing 3, a metal welding frame 2 and a cover plate 1. The metal welding frame 2 is welded to the ceramic housing 3, and the cover plate 1 is further welded to the metal welding frame 2.

[0025] The structural diagram of the cover plate 1 is shown in FIG. Figure 4 As shown, it is provided with a thin edge portion 10 and a thickened portion 11 in the center area to improve its ability to resist deformation, so as to reduce the deformation of the circuit when subjected to external force. However, due to welding requirements, the thickness of the part where the cover plate 1 contacts the metal welding frame 2 is still relatively thin. Parallel seam welding uses an electrode roller to contact the surface of the cover plate 1 and apply a large current. There is a contact resistance between the contact surface of the cover plate 1 and the metal welding frame 2. A large amount of heat is generated after the large current passes, so that the surface of the cover plate 1 and the metal welding frame 2 melts, thereby achieving welding. If the welding part of the cover plate 1 is too thick, it may result in a larger current being applied during welding, resulting in difficulties in controlling the process parameter window, and damage to the outer shell caused by stress generated by excessive temperature. Therefore, the contact part between the cover plate 1 and the metal welding frame 2 still needs to maintain the original thickness.

[0026] The thickness of the part where the cover plate 1 contacts the metal welding frame 2 is still relatively thin, which results in the cover plate 1 being supported at a relatively thin place, and the weak point is transferred to the thick and thin junction of the cover plate 1; the junction will first show plastic deformation marks caused by the large deformation of the cover plate 1, and it cannot be restored, affecting the reliability and appearance of the circuit. In order to solve this technical problem, this embodiment does not start with the structure of the cover plate 1 itself to prevent increasing the difficulty of welding, but creatively improves the structure of the metal welding frame 2, as described below.

[0027] In this embodiment, the metal welding frame 2 has a first support portion 20 and a second support portion 21 from top to bottom, and the width of the metal welding frame 2 is greater than 0.5 mm, wherein the width of the second support portion 21 is greater than 0.2 mm. The width of the first support portion 20 can be consistent with the width of the existing metal welding frame 2.

[0028] The metal welding frame 2 is stepped as a whole, and the distance between the surface of the second support portion 21 and the surface of the first support portion 20 is greater than or equal to the height of the thickened portion 11 in the central area of ​​the cover plate 1 .

[0029] In order to simplify the manufacturing process of the metal welding frame 2 and to improve the overall load-bearing performance of the metal welding frame 2, the metal welding frame 2 is formed into an integral part in this embodiment; it can be achieved by mechanical processing or chemical etching; no complicated process is required. However, due to the simple structure of the metal welding frame 2, for example, the surface of the split second support part 21 is combined with the first support part 20, and the overall structure of the metal welding frame 2 in this embodiment should also fall within the scope of protection of the utility model.

[0030] When the improved metal welding frame 2 is in use, the thin edge portion 10 of the cover plate 1 contacts the surface of the first support portion 20, and the bottom surface portion of the thickened portion 11 in the center area of ​​the cover plate 1 contacts the surface of the second support portion 21. When the bottom edge portion of the thickened portion 11 in the center area of ​​the cover plate 1 directly contacts the surface of the second support portion 21, the second support portion 21 directly provides effective support to the cover plate 1 to prevent the cover plate 1 from deforming.

[0031] Therefore, the metal welding frame 2 effectively supports both the thin edge portion 10 and the thickened portion 11 of the cover plate 1, thereby enhancing the ability of the cover plate 1 to resist deformation and ensuring the reliability and appearance of the circuit.

[0032] Example 2

[0033] The parallel seam welding structure of the large-size ceramic package provided in this embodiment is as follows Figure 5 As shown, the difference from Embodiment 1 is that a gap is provided between the edge portion of the thickened portion 11 in the central area of ​​the cover plate 1 and the surface of the second supporting portion 21 .

[0034] That is, the bottom surface of the thickened portion 11 in the central area of ​​the cover plate 1 is not in direct contact with the surface of the second support portion 21. The gap exists to allow a certain amount of deformation of the thickened portion 11 of the cover plate 1. When the deformation reaches a certain degree, the thickened portion 11 of the cover plate 1 will come into contact with the second support portion 21 of the metal welding frame 2, thereby avoiding further deformation of the cover plate 1.

[0035] The gap between the bottom surface of the thickened portion and the surface of the second support portion is less than 40 μm. The basis for the gap value being less than 40 μm is as follows: Through simulation calculation, when the size of the cover plate 1 is 50 mm × 50 mm (this size is considered a larger size in a ceramic housing), under a constant acceleration of 5000 g, the deformation of the edge of the thickened portion of the cover plate 1 is about 40 μm.

[0036] Compared with the conventional ones, the conventional cover plate 1 can be greatly deformed. When the deformation is too large and the stress of the cover plate 1 exceeds the material strength, irreversible deformation will occur. However, when the gap is set in this embodiment, the cover plate 1 is allowed to deform but not to a large extent. In this way, the ability of the cover plate 1 to resist deformation is enhanced, and the reliability and appearance of the circuit are guaranteed.

[0037] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the purpose and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A parallel seam welding structure of a large-size ceramic package, comprising a ceramic shell, a metal welding frame and a cover plate, wherein the metal welding frame is welded to the ceramic shell, and the cover plate is welded to the metal welding frame, characterized in that: The cover plate is provided with a thin edge portion and a thickened portion in the center area, and the metal welding frame has a first support portion and a second support portion in sequence from top to bottom, and the width of the second support portion is greater than 0.2 mm; the thin edge portion of the cover plate contacts the surface of the first support portion, and the bottom surface of the thickened portion in the center area of ​​the cover plate partially contacts the surface of the second support portion, or a gap is set between the bottom surface of the thickened portion and the surface of the second support portion.

2. The parallel seam welding structure of a large-size ceramic package according to claim 1, characterized in that: The distance between the surface of the second support portion and the surface of the first support portion is greater than or equal to the height of the thickened portion in the central area of ​​the cover plate.

3. The parallel seam welding structure of a large-size ceramic package according to claim 2, characterized in that: The width of the metal welding frame is greater than 0.5 mm.

4. The parallel seam welding structure of a large-size ceramic package according to claim 3, characterized in that: The metal welding frame is integrally formed.

5. The parallel seam welding structure of a large-size ceramic package according to claim 1, characterized in that: The gap between the bottom surface of the thickened portion and the surface of the second supporting portion is less than 40 μm.

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