A package cap with an embedded metal ring, a hermetic packaging shell and its preparation method, and a hermetic packaging

Abstract

This invention relates to the field of electronic component packaging, specifically to a packaging cap with an internal metal ring, a hermetic packaging shell, its preparation method, and hermetic packaging. The cap is mounted on a circuit board and is used to cooperate with leads, glass insulators, and a cap to form a hermetic package of the electronic device. The size of the cap is adapted to the electronic device to be packaged. On the inner side of the cap, there is a cavity structure protruding outwards to accommodate the glass insulator. The cap also includes a flat flash integrally formed around the edge of the cavity structure, with the bottom surface of the flash parallel to the surface of the circuit board used for packaging to ensure a close fit. Inside the cavity structure, there is a metal ring of the same height as the cavity structure. A through hole for inserting leads is provided inside the metal ring on the cap. This invention, by setting the metal ring, ensures a regular shape of the glass insulation structure after fusion sealing, avoiding stress concentration in the glass, thereby solving the problems of cracking and chipping of the glass after fusion sealing.

Description

Technical Field

[0001] This invention relates to the field of electronic component packaging, specifically to a packaging cap with an internal metal ring, a hermetic packaging shell, a method for preparing the same, and hermetic packaging. Background Technology

[0002] In recent years, with the rapid development of intelligence and information technology, the field of electronic components has experienced explosive growth. Emerging and key electronic components, represented by core and basic components, are receiving increasing attention. Electronic components generally consist of internal chips and circuits, substrates, and hermetic packaging shells. The rapid development of electronic components is inseparable from the support of hermetic packaging shells, and the rapid development of electronic components has also driven the development of hermetic packaging shells.

[0003] Core and fundamental electronic components possess strong versatility and interchangeability, and are widely used in various electronic information fields such as telecommunications transmission and intelligent control. They have high requirements for quality stability and batch production; therefore, stringent quality consistency requirements and large-scale production are their prominent characteristics. Hermetic packaging shells, as key components, not only serve to interconnect internal and external circuits but also protect internal circuits and perform other functions. They are the most direct reflection of the performance indicators of electronic components. Therefore, how to achieve large-scale, stable production of packaging shells is a challenge facing the industry.

[0004] For this type of enclosure, considering batch production and quality consistency issues, the industry typically uses a method of stamping the cavity shell and directly filling it with a large, integral glass insulator for sintering. The stamping process creates transition rounded corners at cavity corners or other structural abrupt changes, a limitation inherent to the stamping process itself and one that cannot be completely resolved. Glass is a brittle material, but traditional encapsulation processes, after sintering, cause the glass to form an irregular structure with inflection points along the rounded corners, leading to stress concentration. High stress can easily exceed the yield strength of the glass, resulting in cracks, chipping, and other defects, which are fatal to the enclosure's airtightness. Simultaneously, the capping process generally uses cold-press welding, forcibly sealing the cap and shell through a physical bond. This process applies significant pressure, which is directly transferred to the glass insulator, further increasing the risk of glass cracking. These problems limit the rapid development of encapsulation enclosures and also hinder the rapid rise of core and fundamental electronic components. Summary of the Invention

[0005] To address the problem of glass defects that easily occur in stamped and integral large glass sealing processes, this invention first provides a sealing cap with an internal metal ring.

[0006] The technical solution adopted in this invention is as follows:

[0007] A package cover with an internal metal ring is disposed on a circuit board and is used to cooperate with leads, glass insulators and caps to form an hermetically sealed package for electronic devices.

[0008] The size and shape of the cover are adapted to the electronic device to be packaged. On the inner side of the cover near the circuit board, there is a cavity structure that protrudes towards the outer side away from the circuit board to accommodate the fused glass insulator. The cover also includes a burr integrally formed around the edge of the cavity structure. The burr is flat and its bottom surface is parallel to the surface of the circuit board used for packaging to ensure a good fit. Inside the cavity structure, there is a metal ring of the same height as the cavity structure. The cover has a through hole for inserting leads at a predetermined position inside the metal ring.

[0009] Preferably, the metal ring is made of Kovar alloy, and the shape of the metal ring is adapted to the shape of the fusion-sealed inner cavity of the glass insulator.

[0010] Preferably, the outer edge of the metal ring is 1-2 mm away from the inner wall of the cavity structure.

[0011] Preferably, the sealing substrate is composed of oxygen-free copper disposed on the outer side and Kovar alloy disposed on the inner side.

[0012] Preferably, the oxygen-free copper is TU1, and the Kovar alloy is 4J29 or the iron-nickel alloy 4J42.

[0013] Preferably, the total thickness of the composite of oxygen-free copper and Kovar alloy is 0.1~1.0 mm, wherein the thickness ratio of oxygen-free copper to Kovar alloy is 7:3.

[0014] The present invention also provides an airtight encapsulation housing comprising the aforementioned low glass insulator stress encapsulation cover, a glass insulator disposed in the cavity structure of the cover, and leads inserted in the glass insulator and the cover.

[0015] The above-mentioned method for preparing a hermetic encapsulation shell includes the following steps:

[0016] S1. Using oxygen-free copper and Kovar alloy materials, a packaging cap of the required size is processed by stamping, turning or milling. The cap includes a cavity structure and flash, and through holes are opened in the corresponding positions.

[0017] S2. According to the required size, a metal ring is machined using Kovar alloy, and a lead hole matching the position of the through hole is machined on the glass insulator. The inner diameter of the metal ring is 0.2~0.4 mm larger than that of the glass insulator.

[0018] S3. Assemble the metal ring into the cavity structure, assemble the glass insulator into the inside of the metal ring, and after setting the lead wire, sinter the cap with the metal ring, the glass insulator and the lead wire together at high temperature to seal them into a whole.

[0019] The present invention also provides an airtight package, comprising the above-described airtight package shell and a cap disposed on the surface of the airtight package shell.

[0020] Preferably, the size of the cap matches the cover, and the edge of the cap has an edge whose shape is adapted to the burr of the cover, the lower surface of which fits against the upper surface of the burr of the cover.

[0021] The beneficial effects of this invention are as follows:

[0022] This invention offers significant advantages in both the preparation of the encapsulation shell before packaging and the assembly of electronic components after packaging. It overcomes quality defects in existing products, reduces stress on glass insulators, and improves product reliability. Specifically:

[0023] Before encapsulation, adding a regularly shaped metal ring inside the stamped sealing cavity structure forces the large glass insulation structure after sealing to be confined within the regular metal ring. This ensures a regular shape for the sealed glass insulation structure, avoiding stress concentration caused by inflection points or abrupt changes in the glass, thus solving the problems of cracking and edge chipping in the sealed glass. Simultaneously, because the glass insulator with the added metal ring does not directly contact the encapsulation shell, the risk of cracking caused by sealing pressure is also reduced.

[0024] To achieve the best containment effect, the shape of the metal ring is the same as that of the glass sealing cavity. That is, if the sealing cavity is circular, the metal ring is designed and processed into a circular ring; if the sealing cavity is rectangular, the metal ring is designed and processed into a rectangular ring, and so on.

[0025] This invention employs a monolithic large-scale glass insulation sintering process. Considering the reliability of the sealing, the metal ring is made of Kovar alloy, and the accompanying monolithic glass is made of a material compatible with the sealing process system, such as DM305, BH-G / K, or GBC glass. This is essentially equivalent to glass sealing on the surface of the Kovar alloy, similar to conventional hermetic encapsulation shell manufacturing processes. Therefore, this invention is compatible with conventional encapsulation shell manufacturing platforms, which helps ensure product reliability. This approach significantly reduces the research and development costs and time associated with new materials or processes, and further lowers technical risks, greatly enhancing the operability and feasibility of this invention.

[0026] Regarding the reliability of the sealing cap after the circuit assembly of the packaged casing: Those skilled in the art know that to ensure the sealing reliability of electronic components, sealing or capping is necessary after the internal circuit assembly and debugging are qualified, in order to ensure the formation of a complete device with airtight requirements. Since this invention uses an integral large glass cavity fusion sealing scheme, with the circuit mounted on the upper surface of the casing, only caps with a certain cavity depth can be used for sealing, and flat covers cannot be used.

[0027] In traditional packaging structures, the large glass element is in direct contact with the side of the packaging shell. During the sealing process, the pressure applied to the shell and cap is directly transmitted to the glass insulation structure through the shell side, easily leading to defects such as edge chipping and cracking. This results in the scrapping of electronic components, causing incalculable cost and time losses. This invention, however, uses a gap between the added metal ring and the side of the packaging shell. The force applied during the sealing process is not directly transmitted to the glass insulation structure, minimizing damage to the glass. Therefore, it effectively avoids the shortcomings and defects of traditional structures, solving the resulting quality problems.

[0028] In addition, in traditional hermetic packaging, when the shell and the cover are welded together by parallel seam welding or energy storage welding, foreign matter splashes will be generated to varying degrees. Once the splashed foreign matter contaminates the internal circuit of the device, it will cause unimaginable bad consequences. The generation of this splash is caused by the inherent limitations of the process itself, and it cannot be completely solved or eliminated at the root.

[0029] Mechanical pressure welding is a method of solid-state welding that uses pressure to induce plastic deformation in the metals to be welded, achieving close contact and intergranular bonding through plastic deformation. This process does not produce spatter, making it an effective means of ensuring the stability of high-end electronic components. The prerequisite for mechanical pressure welding is that the components to be welded must have sufficient plastic compression and deformation. Commonly applicable materials include aluminum and copper. However, conventional packaging materials such as Kovar alloy (4J29) and cold-rolled steel have limitations on the application of mechanical pressure welding for capping due to their physical properties.

[0030] This invention uses a composite material of oxygen-free copper (TU1) and Kovar alloy (4J29) to prepare the cap. On the one hand, the oxygen-free copper (TU1) material on the outer surface has a softer and more fluid plastic deformation ability, which enables the cap to be mechanically pressure sealed, fundamentally solving the problem of spatter from hot-press energy storage welding and greatly improving the stability of electronic components. On the other hand, the Kovar (4J29) material on the inner surface can be fused with glass with high reliability, improving the reliability of the shell seal. Attached Figure Description

[0031] Figure 1 A schematic diagram of the encapsulation and sealing structure for low glass insulator stress provided by the present invention;

[0032] Figure 2 for Figure 1 Top view;

[0033] Figure 3 for Figure 1 Enlarged view of Part I;

[0034] Figure 4 A schematic diagram of the encapsulation cover for low-stress glass insulators and the encapsulation shell formed after the glass insulator and lead wire are fused together;

[0035] Figure 5 This is a schematic diagram of the cap's structure;

[0036] Figure 6 This is a schematic diagram of the hermetic seal formed after the encapsulation cover and cap are connected for low glass insulator stress.

[0037] The meanings of the symbols marked in the figure are as follows:

[0038] 10-Cap 11-Outer side 12-Inner side 13-Cavity structure 131-Metal ring 14-Flash 15-Through hole

[0039] 30-Block 31-Fringe

[0040] 41-Lead wire 42-Glass insulator Detailed Implementation

[0041] The technical solution of the present invention will now be described in conjunction with the accompanying drawings to facilitate understanding by those skilled in the art.

[0042] like Figure 1-6 As shown, a package cover with an internal metal ring is disposed on a circuit board or other device and is used to cooperate with the lead wire 41 and the glass insulator 42 to form an airtight package shell for electronic devices.

[0043] The size and shape of the cover 10 are adapted to the electronic device to be packaged. On the inner side 12 of the cover near the circuit board, there is a cavity structure 13 that protrudes toward the outer side 11 away from the circuit board to accommodate the fused glass insulator 42. The cover 10 also includes a burr 14 integrally provided around the edge of the cavity structure 13. The burr 14 is flat and the bottom surface of the burr 14 is parallel to the surface of the circuit board used for packaging to ensure a good fit.

[0044] Inside the cavity structure 13, a metal ring 131 of the same height as the cavity structure 13 is disposed. The metal ring 131 is made of Kovar alloy, and its shape is adapted to the shape of the sealed inner cavity of the glass insulator 42. In this invention, the metal ring 131 is used to limit the volume and shape of the glass insulator 42 after sealing. To ensure the performance, the outer edge of the metal ring 131 is 1-2 mm away from the inner wall of the cavity structure 13, and the inner diameter of the metal ring 131 is 0.2-0.4 mm larger than the original size of the glass insulator 42.

[0045] The cover 10 has a through hole 15 at a set position inside the metal ring 131 for inserting the lead wire 41.

[0046] Furthermore, in this invention, the substrate of the cap 10 is composed of oxygen-free copper disposed on the outer side 11 and Kovar alloy disposed on the inner side 12. In this embodiment, the oxygen-free copper is TU1, the Kovar alloy is 4J29, and the total thickness of the composite of oxygen-free copper and Kovar alloy is 0.1~1.0 mm, wherein the thickness ratio of oxygen-free copper to Kovar alloy is 7:3.

[0047] When the cover 10 of the present invention is used for circuit assembly, a cap 30 is also provided on the outer side of the cover 10 to form an airtight package. In order to match the cover 10 to achieve a better fit, the cap 30 is made of oxygen-free copper TU1, the size of the cap 30 matches the cover 10, the inside of the cap 30 has a cavity to accommodate the cavity structure 13 of the cover 10 and electronic devices, and the edge of the cap 30 has an edge 31 whose shape is adapted to the burr 14 of the cover 10, so as to better form a seal with the cover 10.

[0048] The preparation method of the above-mentioned low-stress package with built-in metal ring includes the following steps:

[0049] S1. Using oxygen-free copper and Kovar alloy materials, a packaging cap 10 of the required size is processed by stamping, turning or milling. The cap 10 includes a cavity structure 13 and a flash 14, and through holes 15 are opened at the corresponding positions.

[0050] S2. According to the required size, a metal ring 131 is machined using Kovar alloy, and a lead hole matching the position of the through hole 15 is machined on the glass insulator 42. The inner diameter of the metal ring 131 is 0.2~0.4 mm larger than that of the glass insulator 42, and the outer diameter is 2~4 mm smaller than that of the inner diameter of the cavity structure 13.

[0051] S3. Assemble the metal ring 131 into the cavity structure 13, assemble the glass insulator 42 into the inside of the metal ring 131, and after setting the lead wire 41, sinter the cover 10 with the metal ring 131, the glass insulator 42 and the lead wire 41 at high temperature. After cooling by the deformation of the glass molten, the cover 10, the metal ring 131 and the lead wire 41 are firmly connected into a whole.

[0052] S4. Use oxygen-free copper TU1 to process the cap 30, and electroplate the cap 30, the lead wire 41 in S3 and the cover 10, wherein the cap 30 is plated with gold or nickel, and the lead wire 41 and the cover 10 are plated with gold, in order to meet the welding requirements and facilitate the implementation of the electroplating process.

[0053] S5. Assemble the cap 30 onto the outer side 11 of the cap in S2, so that the lower surface of the edge 31 of the cap fits against the upper surface of the burr 14 of the cap.

[0054] S6. The cover 10 processed by S4 is encapsulated on the required circuit board, and the electronic components are sealed in the space formed by the cover 10 and the cap 30, thereby forming an airtight packaged device with airtight function.

[0055] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A package cover with an internal metal ring, disposed on a circuit board, for use with a lead (41), a glass insulator (42), and a cap (30) to form a hermetically sealed package for an electronic device, characterized in that, The size and shape of the cover (10) are adapted to the electronic device to be packaged. On the inner side (12) of the cover near the circuit board, there is a cavity structure (13) that protrudes toward the outer side (11) away from the circuit board to accommodate the fused glass insulator (42). The cover (10) also includes a burr (14) integrally provided around the edge of the cavity structure (13). The burr (14) is flat and the bottom surface of the burr (14) is parallel to the surface of the circuit board used for packaging to ensure a close fit. Inside the cavity structure (13), there is also a metal ring (131) of the same height as the cavity structure (13). The cover (10) has a through hole (15) for inserting the lead wire (41) at a set position inside the metal ring (131). The metal ring (131) is made of Kovar alloy, and the shape of the metal ring (131) is adapted to the shape of the fusion-sealed inner cavity of the glass insulator (42). The outer edge of the metal ring (131) is 1-2 mm away from the inner wall of the cavity structure (13).

2. The encapsulation cap with an internal metal ring as described in claim 1, characterized in that, The substrate of the cover (10) is composed of oxygen-free copper disposed on the outer side (11) and Kovar alloy disposed on the inner side (12).

3. The encapsulation cap with an internal metal ring as described in claim 2, characterized in that, The oxygen-free copper is TU1, and the Kovar alloy is 4J29 or the iron-nickel alloy 4J42.

4. The encapsulation cap with an internal metal ring as described in claim 3, characterized in that, The total thickness of the composite of oxygen-free copper and Kovar alloy is 0.1~1.0 mm, wherein the thickness ratio of oxygen-free copper to Kovar alloy is 7:

3.

5. A hermetic encapsulation shell, characterized in that, The encapsulation housing includes a cap (10) as described in any one of claims 1-4, a glass insulator (42) disposed in the cavity structure (13) of the cap (10), and a lead wire (41) inserted in the glass insulator (42) and the cap (10).

6. A method for preparing a hermetic encapsulation shell as described in claim 5, characterized in that, The steps are as follows: S1. Using oxygen-free copper and Kovar alloy materials, a packaging cap (10) of the required size is processed by stamping, turning or milling. The cap (10) includes a cavity structure (13) and a flash (14), and through holes (15) are opened in the corresponding positions. S2. According to the required size, a metal ring (131) is machined using Kovar alloy, and a lead hole matching the position of the through hole (15) is machined on the glass insulator (42). The inner diameter of the metal ring (131) is 0.2~0.4 mm larger than that of the glass insulator (42). S3. Assemble the metal ring (131) into the cavity structure (13), assemble the glass insulator (42) into the inside of the metal ring (131), set the lead wire (41), and then sinter the cover (10) with the metal ring (131), the glass insulator (42) and the lead wire (41) together at high temperature to seal them into a whole.

7. A hermetic encapsulation, characterized in that, The device includes a hermetic encapsulation housing as described in claim 5, and a cap (30) disposed on the surface of the hermetic encapsulation housing, wherein the lower edge of the cap (30) is in contact with the upper surface of the burr (14) of the cover (10).

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