A screw cap type packaging structure

Abstract

The utility model discloses a screw cap formula packaging structure, including the packaging shell, screw cap, chip and printed circuit board, the printed circuit board is installed in the bottom of packaging shell, the chip is installed in the printed circuit board surface, the area of printed circuit board is greater than the area of chip, after the chip installation, the edge area of a circle of printed circuit board surface is not covered by chip, screw cap outer wall is equipped with outer thread, and the inner wall of packaging shell is equipped with inner thread, and screw cap is installed in the packaging shell through thread, and screw cap exerts uniform pressure to the edge area of a circle of printed circuit board surface. The screw cap formula packaging structure provided by the utility model can overcome the uneven stress of the device packaging structure in the prior art and cause the poor reliability of the device, and also reduce the process complexity, improve the production efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of semiconductor processing technology, and specifically relates to a screw-cap type packaging structure. Background Technology

[0002] Existing MEMS device metal packaging structures typically use multiple screws or adhesive to fix the MEMS device to the metal casing. This method of fixing the device and its metal shell with multiple screws or adhesive has drawbacks besides being complex and inefficient in assembly and production. Because the micron / nanoscale sensitive structures of MEMS devices have extremely low strength, when using multiple screws for fixing, differences in screw torque and structural position at various connection points can easily lead to uneven stress on the PCB board within the MEMS device, thus affecting its mechanical performance and reliability. Stress: When an object is subjected to external forces or non-uniform temperature fields, the internal interaction forces generated to resist deformation or damage are called stress. When using adhesive to fix the MEMS device to the metal casing, the adhesive usually requires high-temperature curing. During the cooling process after curing, the shrinkage of the adhesive causes changes in the stress on the PCB board of the MEMS device, which also affects the mechanical performance and reliability of the device. In addition, after the adhesive cures, it fills the gaps that originally existed between the MEMS device and the encapsulated metal shell, resulting in a higher impact transmission rate, which makes the sensitive structure of the device more susceptible to damage and its mechanical reliability lower. Utility Model Content

[0003] In view of all or part of the shortcomings of the prior art described above, the purpose of this utility model is to provide a screw cap packaging structure that can overcome the problem of poor device reliability caused by uneven stress in the device packaging structure in the prior art, while also reducing process complexity and improving production efficiency.

[0004] To achieve the above-mentioned objectives, this utility model provides the following technical solution:

[0005] This utility model provides a screw-on packaging structure, including a packaging shell, a screw cap, a chip, and a printed circuit board. The printed circuit board is installed at the bottom of the packaging shell, and the chip is installed on the surface of the printed circuit board. The area of ​​the printed circuit board is larger than the area of ​​the chip. After the chip is installed, a ring edge area on the surface of the printed circuit board is not covered by the chip. The outer wall of the screw cap has external threads, and the inner wall of the packaging shell has internal threads. The screw cap is installed in the packaging shell through the threads, and the screw cap applies uniform pressure to a ring edge area on the surface of the printed circuit board.

[0006] The aforementioned screw-on packaging structure features external threads on the screw cap and internal threads on the packaging shell (base plate). This ensures that the two can be assembled and disassembled by rotating the screw cap. Tightening a single screw cap secures the device (including the chip and printed circuit board) to the packaging shell. Compared to machining the screw cap internally and the packaging shell externally, this invention allows the screw cap to be hidden inside the packaging shell, reducing its footprint without affecting subsequent use. The screw cap is less susceptible to external influences that could cause malfunctions in the internal chip and printed circuit board. If the screw cap were located outside the packaging shell, it would be easily affected by external factors. The screw cap applies uniform pressure to the edge area of ​​the printed circuit board (PCB), ensuring uniform pressure around the chip. When the screw cap is tightened, pressure is applied directly to the printed circuit board, not the chip, minimizing stress on the central chip area and resulting in higher mechanical reliability. Furthermore, this screw-on packaging structure is simple to manufacture and has high installation efficiency.

[0007] In some technical solutions, the bottom surface of the printed circuit board is attached to the bottom of the package shell, and the chip is mounted on the side of the printed circuit board facing the screw cap.

[0008] In other technical solutions, the bottom of the package is provided with a mounting slot for mounting the chip, and the chip is mounted on the side of the printed circuit board away from the screw cap.

[0009] The encapsulation shell is a metal annular or square tubular shell, and the main structure of the screw cap is a circular pressure cap. A gap is left between the printed circuit board and the inner wall of the encapsulation shell. This gap prevents the encapsulation shell from adversely affecting the printed circuit board, thereby impacting the electrical performance of the device.

[0010] The cap has an annular protrusion facing the printed circuit board (PCB). The surface of the annular protrusion that contacts the PCB serves as a pressure surface, and the pressure surfaces of the cap and the PCB are concentric circles. This pressure surface can be located on the edge region of the PCB on the side where the chip is located, or in other designs, on the edge region of the side without the chip. Friction inevitably exists between the PCB and the circular cap / cap, which will affect the stress distribution of the PCB. The circular cap applies pressure and friction evenly to the PCB through its centrally hollowed-out concentric circular contact surface, i.e., the annular protrusion, resulting in a uniform stress distribution. Placing the chip in the central circular stress distribution region of the PCB, i.e., with the chip's microstructure at the center of the concentric circles, reduces strain and improves the reliability of the chip's microstructure.

[0011] The pressure-applying surface of the annular protrusion is smooth, flat, and burr-free. The pressure-applying surfaces of the screw cap and the PCB board are concentric circles and must be flat and burr-free to ensure uniform pressure around the edge of the chip on the printed circuit board.

[0012] The highest point of the upper surface of the cap is lower than the highest point of the upper surface of the package shell, and the cap is completely inside the package shell when screwed on. After the cap is screwed on, a certain distance must be maintained between the upper surface of the cap and the upper surface of the package shell, so that the cap does not directly contact the later mounting surface of the device. This avoids the cap loosening due to contact between the package structure and the later mounting surface of the device. At the same time, by reducing the contact area between the package structure and the later mounting surface of the device, the transmission rate of external vibration and impact to the device is reduced, the sensitive structure of the device is not easily damaged, and the mechanical reliability is high.

[0013] The printed circuit board and the package housing are provided with mating positioning pin holes to ensure the positional accuracy of the PCB board within the package housing / package tube.

[0014] The chip is a MEMS chip, and the MEMS chip and the printed circuit board constitute a MEMS device.

[0015] The center of the cap is sealed or hollowed out, and the cap is provided with an installation auxiliary structure, which is an internal hexagonal structure formed on the surface of the cap. An installation tool matching structure is required on the outer side of the cap to facilitate disassembly and installation. For example, it can be used with a mechanical wrench to achieve a tight seal. Its structure is simple, does not occupy extra space, is easy to operate, and the clamping force meets the requirements.

[0016] The chip is mounted on the surface of the printed circuit board by adhesive and is located in the middle of the printed circuit board. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the specific embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a screw-on packaging structure provided in Embodiment 1.

[0019] Figure 2 This is a schematic diagram of a screw-on packaging structure provided in Embodiment 2.

[0020] Figure 3 This is a first exploded view of a screw-on packaging structure provided in Embodiment 2.

[0021] Figure 4 This is a second exploded view of a screw-on packaging structure provided in Embodiment 2.

[0022] Reference numerals: 1-Encapsulation shell; 2-Screw cap; 3-Chip; 4-Printed circuit board; 5-Annular protrusion; 6-Edge area; 7-Mounting groove; 8-Positioning pin hole; 9-Positioning pin; 10-Galvanometer lens; 11-Internal hexagonal structure. Detailed Implementation

[0023] The technical solutions in specific embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0024] Example 1

[0025] A screw-on cap packaging structure, see Figure 1 The package includes a housing 1, a screw cap 2, a chip 3, and a printed circuit board 4. The housing 1 is a metal annular tubular shell, and the screw cap 2 has a circular pressure cap structure. In other embodiments, the housing 1 can also be a square tubular shell. The printed circuit board 4 is mounted on the bottom of the housing 1, with its bottom surface fitting against the bottom of the housing 1. A gap is left between the printed circuit board 4 and the inner sidewall of the housing 1. The printed circuit board 4 and the housing 1 have mating positioning pin holes (not shown) to ensure the positional accuracy of the PCB board within the housing 1.

[0026] Chip 3 is mounted on the surface of printed circuit board 4 using adhesive. Chip 3 is located in the center of printed circuit board 4, facing the screw cap 2. The area of ​​printed circuit board 4 is larger than the area of ​​chip 3. After chip 3 is mounted, a ring edge area 6 on the surface of printed circuit board 4 is not covered by chip 3. Chip 3 is a MEMS chip. The MEMS chip and printed circuit board 4 constitute a MEMS device. In other embodiments, chip 3 can also be other types of chips that are sensitive to stress, have high requirements for mechanical performance and mechanical stability, resulting in very high packaging requirements.

[0027] The outer wall of the cap 2 has external threads (not shown), and the inner wall of the encapsulation shell 1 has internal threads (not shown). The cap 2 is installed inside the encapsulation shell 1 via these threads. The center of the cap 2 is sealed or hollowed out. The cap 2 has an installation auxiliary structure, which is a hexagonal internal structure (not shown) formed on the surface of the cap 2. The hexagonal internal structure is located on the upper surface of the cap 2 and can be directly formed on the surface of the cap 2 without the need for other complex components. In other embodiments, the installation auxiliary structure can also be other structures, such as a stop knob, as long as it can be tightened. The hexagonal internal structure can be used with a mechanical wrench to achieve a tight seal. It has a simple structure, does not take up extra space, is easy to operate, and the clamping force meets the requirements.

[0028] The cap 2 has an annular protrusion 5 facing the printed circuit board 4. The space formed by the annular protrusion 5 (annular stepped surface) ensures that the cap 2 does not directly contact the upper surface or the side of the chip 3, leaving gaps in both directions. The pressure-applying surface of the annular protrusion 5 is smooth and burr-free. The surface of the annular protrusion 5 that contacts the printed circuit board 4 serves as the pressure-applying surface. The pressure-applying surfaces of the cap 2 and the printed circuit board 4 are concentric circles, and the cap 2 applies uniform pressure to a ring-shaped edge region 6 on the surface of the printed circuit board 4. When the cap 2 is tightened, the highest point of the upper surface of the cap 2 is lower than the highest point of the upper surface of the package 1, and the cap 2 is completely inside the package 1 when tightened.

[0029] Example 2

[0030] A screw-on cap packaging structure, see Figures 2 to 4 The package includes a housing 1, a screw cap 2, a chip 3, and a printed circuit board 4. The housing 1 is a metal annular tubular shell, and the screw cap 2 has a circular pressure cap structure. In other embodiments, the housing 1 can also be a square tubular shell. The printed circuit board 4 is mounted on the bottom of the housing 1, and the bottom of the housing 1 has a mounting groove 7 for mounting the chip 3. A gap is left between the printed circuit board 4 and the inner sidewall of the housing 1. The printed circuit board 4 and the housing 1 have mutually cooperating positioning pin holes 8 and are equipped with two positioning pins 9 to ensure the positional accuracy of the PCB board in the housing 1.

[0031] Chip 3 is mounted on the surface of printed circuit board 4 using adhesive. Chip 3 is located in the center of printed circuit board 4, on the side of printed circuit board 4 away from the screw cap 2. In this embodiment, it is a square chip. The area of ​​printed circuit board 4 is larger than the area of ​​chip 3. After chip 3 is mounted, a ring edge area 6 on the surface of printed circuit board 4 is not covered by chip 3. The edge area 6 of printed circuit board 4 is mounted above the chip mounting slot 7 and is attached to the package shell 1. Chip 3 is a MEMS chip and also includes a circular galvanometer mirror 10. The MEMS chip with the circular galvanometer mirror 10 attached and the printed circuit board 4 constitute a MEMS device. In other embodiments, chip 3 can also be other types of chips that are sensitive to stress, have high requirements for mechanical performance and mechanical stability, resulting in very high packaging requirements.

[0032] The outer wall of the cap 2 has external threads (not shown), and the inner wall of the encapsulation shell 1 has internal threads (not shown). The cap 2 is installed inside the encapsulation shell 1 via these threads. The center of the cap 2 is hollowed out, and the cap 2 has an installation auxiliary structure. The installation auxiliary structure is an internal hexagonal structure 11 formed on the surface of the cap 2. The internal hexagonal structure 11 is located on the upper surface of the cap 2. It can be directly formed on the surface of the cap 2 without the need for other complex components. In other embodiments, the installation auxiliary structure can also be other structures, such as a stop knob, as long as it can be tightened. The internal hexagonal structure 11 can be used with a mechanical wrench to achieve a tight seal. Its structure is simple, does not take up extra space, is easy to operate, and the clamping force meets the requirements.

[0033] The cap 2 has an annular protrusion 5 facing the printed circuit board 4. The pressure-applying surface of the annular protrusion 5 is smooth, flat, and burr-free. The surface of the annular protrusion 5 that contacts the printed circuit board 4 serves as the pressure-applying surface. The pressure-applying surfaces of the cap 2 and the printed circuit board 4 are concentric circles. The cap 2 applies uniform pressure to a ring-shaped edge region 6 on the surface of the printed circuit board 4. When the cap 2 is tightened, the highest point of the upper surface of the cap 2 is lower than the highest point of the upper surface of the package 1, and the cap 2 is completely inside the package 1 when tightened.

[0034] The main difference between Embodiment 1 and Embodiment 2 lies in the different mounting positions of the chip 3. Depending on the type of chip and packaging requirements, either the packaging structure of Embodiment 1 or the packaging structure of Embodiment 2 can be freely selected.

[0035] The following describes the usage of the screw-on cap packaging structure provided in Example 1 / Example 2:

[0036] After chip 3 is glued and mounted onto printed circuit board 4, it is placed into package housing 1. Positioning pin 9 ensures the positional accuracy between printed circuit board 4 and package housing 1. Package housing 1 and screw cap 2 are threaded together. Using the internal hexagonal structure 11 on the outer upper surface of screw cap 2, screw cap 2 is rotated with a wrench. The lower edge of screw cap 2, i.e., the annular protrusion 5, presses against the edge area 6 of printed circuit board 4, thereby securing the MEMS device and completing the encapsulation. To remove it, simply loosen screw cap 2 with a wrench, remove screw cap 2, and then remove chip 3 and printed circuit board 4.

[0037] The screw-on MEMS device metal packaging structure provided in the above embodiments uses a circular cap, i.e., a screw cap 2, to press against the edge area 6 around the printed circuit board 4 of the MEMS device. By uniformly applying pressure to press the MEMS device against the metal casing, the MEMS device is packaged. The packaging structure is simple. Compared to existing packaging methods that use point contact to press the printed circuit board, the packaging structure provided in this embodiment can overcome the problem of poor reliability of MEMS devices due to uneven stress in existing metal packaging structures. It also reduces process complexity and improves production efficiency.

[0038] The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the scope of protection of the claims of this utility model.

Claims

1. A screw-on cap type packaging structure, characterized in that, The package includes a housing (1), a screw cap (2), a chip (3), and a printed circuit board (4). The printed circuit board (4) is installed at the bottom of the housing (1), and the chip (3) is installed on the surface of the printed circuit board (4). The area of ​​the printed circuit board (4) is larger than the area of ​​the chip (3). After the chip (3) is installed, a ring edge area (6) on the surface of the printed circuit board (4) is not covered by the chip (3). The outer wall of the screw cap (2) is provided with external threads, and the inner wall of the housing (1) is provided with internal threads. The screw cap (2) is installed in the housing (1) by the threads. The screw cap (2) applies uniform pressure to a ring edge area (6) on the surface of the printed circuit board (4).

2. The screw-on cap packaging structure according to claim 1, characterized in that, The bottom surface of the printed circuit board (4) is attached to the bottom of the package (1), and the chip (3) is mounted on the side of the printed circuit board (4) facing the screw cap (2).

3. The screw-on cap packaging structure according to claim 1, characterized in that, The bottom of the package (1) is provided with a mounting groove (7) for mounting the chip (3), and the chip (3) is mounted on the side of the printed circuit board (4) away from the screw cap (2).

4. The screw-on cap packaging structure according to claim 1, characterized in that, The encapsulation shell (1) is a metal ring or square tubular shell, the main structure of the screw cap (2) is a circular pressure cap, and there is a gap between the printed circuit board (4) and the inner wall of the encapsulation shell (1).

5. The screw-on cap packaging structure according to claim 1, characterized in that, The screw cap (2) has an annular protrusion (5) facing the printed circuit board (4). The surface of the annular protrusion (5) that contacts the printed circuit board (4) serves as a pressure surface. The pressure surfaces of the screw cap (2) and the printed circuit board (4) are concentric.

6. The screw-on cap packaging structure according to claim 5, characterized in that, The pressure surface of the annular protrusion (5) is smooth, flat and burr-free.

7. The screw-on cap packaging structure according to claim 1, characterized in that, The highest point of the upper surface of the screw cap (2) is lower than the highest point of the upper surface of the encapsulation shell (1), and the screw cap (2) is completely inside the encapsulation shell (1) when screwed on.

8. The screw-on cap packaging structure according to claim 1, characterized in that, The printed circuit board (4) and the package shell (1) are provided with mutually cooperating positioning pin holes (8); the chip (3) is a MEMS chip, and the MEMS chip and the printed circuit board (4) constitute a MEMS device.

9. A screw-on cap packaging structure according to claim 1, characterized in that, The center of the cap (2) is sealed or hollowed out, and the cap (2) is provided with an installation auxiliary structure, which is an internal hexagonal structure (11) formed on the surface of the cap (2).

10. A screw-on cap packaging structure according to claim 1, characterized in that, The chip (3) is mounted on the surface of the printed circuit board (4) by adhesive curing, and the chip (3) is located in the middle of the printed circuit board (4).

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