A mounting structure for SOP packaged devices of aerospace electronic products

Abstract

The present invention relates to an installation method for aerospace electronic products SOP package 3D-PLUS devices, the method includes the design of electrical auxiliary parts of SOP package 3D-PLUS, the pasting of electrical auxiliary parts, device welding, and adhesive reinforcement process methods, and belongs to the field of electronic assembly process technology. The present invention proposes a process that can realize the reflow welding and then reinforcement of SOP package 3D-PLUS devices. By designing suitable electrical auxiliary parts, coordinating specific process flows and adhesive reinforcement methods, automatic welding of SOP package 3D-PLUS devices can be realized, and back-end reliability reinforcement can be performed, avoiding the interlacing of welding and adhesive reinforcement processes of SOP package 3D-PLUS devices during the assembly process, improving the production efficiency of devices from manual welding to automatic welding, and at the same time improving the consistency and reliability of welding and reinforcement.

Description

Technical Field

[0001] The invention relates to an installation structure and method for a 3D-PLUS device of an aerospace electronic product SOP package. The method comprises a process method for designing electrical auxiliary parts of the SOP package 3D-PLUS, pasting the electrical auxiliary parts, welding the device, and adhesive reinforcement, and belongs to the technical field of electronic assembly process. Background Art

[0002] SOP package 3D-PLUS is the abbreviation of three-dimensional stacked package. It is a chip package developed by the French SOP package 3D-PLUS company in response to the actual needs of the Galileo program and other aerospace, aviation and other fields. Compared with other packages, under the premise of the same weight, the capacity can be increased by more than 2,000 times. Therefore, this packaged device has technical advantages such as high integration and superior electronic performance in practical applications, and is widely used in aerospace products. However, due to the large size of the device body, the high center of gravity, and the lack of stress release bends on the pins, the vibration resistance is weak after being assembled on the printed circuit board. The reinforcement of the device is very important for the entire assembly process.

[0003] Many users in the military field still use manual methods to weld SOP packaged 3D-PLUS devices. Before manual welding of the device, epoxy glue is applied between the bottom of the device and the PCB substrate, and then the device and the PCB pad are positioned and welded. This method can better reinforce the device, but the production efficiency is low, which restricts the increase in production capacity; a few users implement automatic welding of SOP packaged 3D-PLUS devices by reflow soldering, but after welding, the device can only be reinforced by end sealing. Compared with bottom filling, the end sealing reinforcement method has weaker mechanical resistance and it is difficult to meet the harsh mechanical conditions of random vibration total root mean square of more than 20g. There was a case in which a certain aerospace stand-alone product had a failure problem of SOP packaged 3D-PLUS device during the test phase of the sample product. After inspection, it was found that the device was reinforced by end sealing. Under the large mechanical environment, cracks appeared in multiple pins of the device solder joints, resulting in abnormal signals. Finally, the device was reinforced by manual welding and bottom filling epoxy glue during the rework phase. After verification, no problems occurred. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art, to realize efficient automatic welding and reliable reinforcement of SOP package 3D-PLUS, and to propose an installation method for SOP package 3D-PLUS devices for aerospace electronic products.

[0005] The technical solution of the present invention is:

[0006] A mounting structure for aerospace electronic product SOP package 3D-PLUS device, comprising a substrate, the substrate surface having PCB pads; an electrical auxiliary component connected to the PCB substrate surface, the inner side of the PCB pads being between two rows of pads; a device located on a side of the electrical auxiliary component away from the substrate, the pins connected to the device are located on both sides of the electrical auxiliary component, the electrical auxiliary component forms a separation area on the PCB substrate separated from the area where the pins of the device are located, and reinforcing glue is provided between the bottom of the device and the PCB substrate and in the separation area.

[0007] The electrical auxiliary component comprises two blocking rods and a crossbeam integrally connected between the two blocking rods, and the two blocking rods are located on one side of the pin.

[0008] Preferably, the electrical auxiliary component is in an "H" shape. In this case, the crossbeam is connected to the middle of the two blocking rods.

[0009] Optionally, the electrical auxiliary part is in a "C" shape. In this case, the crossbeam is connected to the same end of the two blocking rods.

[0010] A method for installing a 3D-PLUS device in a SOP package for aerospace electronic products, comprising:

[0011] Design and manufacture electrical auxiliary parts corresponding to the devices;

[0012] Complete solder paste printing on PCB pads;

[0013] Paste the electrical auxiliary parts on the side of the PCB pad where the solder paste is printed;

[0014] The device is mounted on the PCB substrate and located at the center of the inner side of the PCB pad. The device is located on the side of the electrical auxiliary component away from the PCB substrate. The pins connected to the device are located on both sides of the electrical auxiliary component. The electrical auxiliary component forms a separation area on the PCB substrate that is not connected to the area where the two rows of pins are located. The electrical auxiliary component is reflow soldered together with the PCB substrate and the device. The epoxy glue at the bottom of the electrical auxiliary component is cured during the high temperature process of reflow soldering to obtain a PCBA assembly;

[0015] Bottom adhesive reinforcement: Inject and cure the reinforcement glue at the bottom of the device and in the separation area of ​​the PCBA assembly.

[0016] Appropriate electrical auxiliary parts should be designed and produced for different devices.

[0017] Specifically, the height difference between the electrical auxiliary component and the bottom of the device body to the bottom of the pin is 0.2mm to 0.3mm. Ensure that there is a gap between the upper end of the electrical auxiliary component and the bottom of the device, so that when the bottom is glued and reinforced, the reinforcement glue can flow to the bottom of the device, and the reinforcement glue will not overflow the separation area from the gap between the upper end of the electrical auxiliary component and the bottom of the device.

[0018] The overall outer width of the electrical auxiliary component is the inner side spacing of the PCB pad minus 1.5mm-2mm, and the spacing between the two blocking rods of the electrical auxiliary component is 1 / 4-1 / 3 of the width of the device; the overall length of the electrical auxiliary component is the length of the device body minus 1.5mm-2mm; the width of the blocking rod of the electrical auxiliary component is 0.6mm-1mm.

[0019] The electrical auxiliary parts are adhered to the PCB substrate by epoxy glue.

[0020] When using epoxy glue to stick the electrical auxiliary parts, apply the epoxy glue to the crossbeam position of the electrical auxiliary parts, and then stick the electrical auxiliary parts to the center position of the inner side of the PCB pad.

[0021] After the device is mounted, the pin offset is less than 10% of the PCB pad width.

[0022] The material of the electrical auxiliary parts is consistent with that of the substrate, which is polyimide.

[0023] The reinforcing glue used for the bottom adhesive reinforcement is epoxy glue, and the composition of the epoxy glue includes ECCOBOND 55 / 9 and talcum powder filler. The composition of ECCOBOND 55 / 9 is ECCOBOND55 and Catalyst9. Based on the mass of ECCOBOND55 being 100 parts, the mass of Catalyst9 is 11.64-12.36 parts, and the mass of talcum powder is 50 parts. The preparation method of the epoxy glue is: ECCOBOND55, Catalyst9 and talcum powder are stirred and mixed in an "8" shape to obtain the epoxy glue.

[0024] The bottom adhesive reinforcement method comprises: using an injection tool to inject epoxy glue into the bottom of the device until the glue overflows, stopping the glue dispensing, and curing at room temperature.

[0025] Specifically, pour the prepared epoxy glue into a 6ml syringe, install a glue injection hose on the head of the syringe, connect the tail to the glue dispensing machine, extend the glue dispensing head into the bottom of the device, start the glue dispensing machine until the glue overflows, stop dispensing, and use the same method to inject epoxy glue to reinforce the other end of the device.

[0026] The epoxy adhesive is cured at room temperature for 24 hours.

[0027] The electrical auxiliary component is fixed to the PCB substrate by epoxy glue, and the epoxy glue component between the electrical auxiliary component and the PCB substrate is the same as the reinforcing glue material used for bottom adhesive reinforcement.

[0028] In summary, this application at least includes the following beneficial technical effects:

[0029] The invention proposes an installation method for a SOP packaged 3D-PLUS device of aerospace electronic products. By designing suitable electrical auxiliary parts for different SOP packaged 3D-PLUS devices and presetting the parts before electrical installation, high-reliability reinforcement of the SOP packaged 3D-PLUS device after automatic welding can be achieved, and the interlacing of welding and adhesive reinforcement processes of the SOP packaged 3D-PLUS device during assembly can be reduced, thereby improving the production efficiency of the device from manual welding to automatic welding, and at the same time improving the consistency and reliability of welding and reinforcement, and the method can be reliably used under severe mechanical conditions with a total root mean square of random vibration of more than 20g. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the installation structure of the SOP package 3D-PLUS device in an embodiment of the present application;

[0031] Figure 2 It is a schematic diagram of the structure of the electrical auxiliary components in the embodiment of the present application;

[0032] Figure 3 It is a schematic diagram of the structure after the electrical auxiliary components in the embodiment of the present application are bonded to the PCB substrate.

[0033] Description of reference numerals: 1. Overall width of the electrical auxiliary component, 2. Height of the electrical auxiliary component, 3. Inner spacing of the electrical auxiliary component, 4. Width of the blocking rod of the electrical auxiliary component, 5. Length of the electrical auxiliary component;

[0034] 6. Substrate; 61. PCB pad; 62. Inside of PCB pad

[0035] 7. Electrical auxiliary parts; 71. Blocking rod; 72. Crossbeam;

[0036] 8. Device; 81. Pin;

[0037] Among them, the distance between the blocking rods of the electrical auxiliary parts is the inner side spacing of the electrical auxiliary parts. DETAILED DESCRIPTION

[0038] The present application is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0039] In this embodiment, the device is a SOP package 3D-PLUS device.

[0040] The present application embodiment discloses a mounting structure and method for a 3D-PLUS device 8 for SOP packaging of aerospace electronic products, referring to Figure 1 and Figure 2The installation structure includes a PCB substrate 6 with a PCB pad 61 on the surface, an electrical auxiliary component 7 connected to the surface of the PCB substrate 6, and a device 8. The device 8 is located on the side of the electrical auxiliary component 7 away from the substrate 6. The pins 81 connected to the device 8 are located on both sides of the electrical auxiliary component 7. The electrical auxiliary component 7 forms a separation area on the PCB substrate 6 that is separated from the area where the pins 81 of the device 8 are located. Reinforcement glue is provided between the bottom of the device 8 and the PCB substrate 6 and in the separation area. The inner side 62 of the PCB pad is between the two rows of pads of the PCB pad 61.

[0041] Reference Figure 3 The electrical auxiliary component 7 includes two blocking rods 71 ​​and a crossbeam 72 integrally connected between the two blocking rods 71, and the two blocking rods 71 ​​are located on one side of the pin 81. Preferably, the crossbeam 72 is connected to the middle of the two blocking rods 71, so that the electrical auxiliary component 7 is "H" shaped.

[0042] The installation method includes the following steps:

[0043] (1) Design and produce appropriate electrical auxiliary parts 7 for different SOP package 3D-PLUS devices 8.

[0044] Design principles of the electrical auxiliary component 7: the material of the electrical auxiliary component 7 is consistent with the PCB substrate, which is polyimide; the electrical auxiliary component 7 is "H"-shaped; the height difference between the electrical auxiliary component 7 and the bottom of the device 8 body to the bottom of the pin 81 is controlled at 0.2mm~0.3mm, ensuring that there is a gap between the upper end of the electrical auxiliary component 7 and the bottom of the device 8; the overall outer width of the electrical auxiliary component 7 is the spacing of the inner side 62 of the PCB pad minus 1.5mm-2mm, and the inner spacing of the electrical auxiliary component 7 is 1 / 4-1 / 3 of the width of the device 8 body; the overall length of the electrical auxiliary component 7 is the length of the device 8 body minus 1.5mm-2mm; the width of the blocking rod 71 of the electrical auxiliary component 7 is 0.6mm-1mm.

[0045] (2) Use a screen printer to print solder paste on the PCB pad 61, and then use epoxy glue to stick the electrical auxiliary component 7 of step (1) to the center position of the inner side 62 of the PCB pad.

[0046] The epoxy adhesive used is ECCOBOND 55 / 9, and the ratio is ECCOBOND55:Catalyst9=100×(1±3%):12×(1±3%) (weight ratio).

[0047] The preparation method of epoxy glue is: stir and mix ECCOBOND55 and Catalyst9 in an "8" shape to obtain epoxy adhesive. After the epoxy glue is prepared, let it stand for 1 hour and use it within 2 hours.

[0048] When using epoxy glue to paste the electrical auxiliary component 7, apply a proper amount of epoxy glue to the crossbeam 72 of the "H"-shaped electrical auxiliary component 7, and then paste the electrical auxiliary component 7 to the center of the inner side 62 of the PCB pad. After pasting, press the electrical auxiliary component 7 lightly to ensure that the electrical auxiliary component 7 and the substrate 6 are in a fitted state and the epoxy glue does not overflow to the PCB pad 61.

[0049] (3) Use a chip mounter or a rework station to mount the SOP package 3D-PLUS device 8. After the device 8 is mounted, the pin 81 is offset by less than 10% of the pad width. The electrical auxiliary component 7 is reflow soldered together with the device 8 to solder the SOP package 3D-PLUS device 8 to the PCB substrate 6. At the same time, the epoxy glue at the bottom of the electrical auxiliary component 7 is cured during the high temperature process of reflow soldering to obtain PCBA.

[0050] (4) The bottom of the SOP package 3D-PLUS device 8 on the PCBA is glued and reinforced.

[0051] The epoxy adhesive used for bottom bonding reinforcement is ECCOBOND 55 / 9 + talcum powder, and the ratio is ECCOBOND55: Catalyst9: talcum powder = 100×(1±3%): 12×(1±3%): 50×(1±3%) (weight ratio).

[0052] The preparation method of epoxy adhesive is as follows: an electronic balance is used to prepare the epoxy adhesive, and materials are taken according to ECCOBOND55: Catalyst9: talcum powder = 100×(1±3%): 12×(1±3%): 50×(1±3%) (weight ratio), and ECCOBOND55, Catalyst9 and talcum powder are stirred and mixed in a container in an "8" shape using a small wooden stick to obtain an epoxy adhesive.

[0053] The reinforcement method is: pour the configured epoxy adhesive into a 6ml syringe, install a glue injection hose on the head of the syringe, connect the tail to the glue dispensing machine, extend the glue dispensing head into the bottom of the device 8, start the glue dispensing machine, and wait until the glue overflows (the glue fills the space between the bottom of the device 8 and the substrate 6, and overflows from the open end of the separation area, and does not overflow from the gap between the device 8 and the top of the electrical auxiliary component 7), stop dispensing, and use the same method to perform epoxy glue injection reinforcement on the other end of the device 8 to complete the bottom bonding reinforcement of the device 8.

[0054] The epoxy adhesive was cured at room temperature for 24 hours.

[0055] The final PCBA board assembly was subjected to environmental testing in accordance with ECSS-Q-ST-70-08C. After the test and assessment, the metallographic structure of the solder joints showed no cracks. The test results showed that the standard qualification criteria were met.

[0056] Example 1

[0057] A method for installing a SOP packaged 3D-PLUS device 8 for aerospace electronic products, wherein the SOP packaged 3D-PLUS device 8 is a SOP64 package, the device 8 body length is 28 mm, the body width is 10.95 mm, the distance from the bottom of the device 8 body to the bottom of the pin 81 is 1.25 mm, and the inner side spacing of the device 8 pad is 6.5 mm. The steps of the method include:

[0058] (1) Design and produce an electrical auxiliary component 7 for the 3D-PLUS device 8 of SOP64 package. The material of the electrical auxiliary component 7 is polyimide; the electrical auxiliary component 7 is in an "H" shape; the height of the electrical auxiliary component 7 is 1.05 mm, and the height difference from the device 8 body to the bottom of the device 8 pin 81 is 0.2 mm; the overall outer width of the electrical auxiliary component 7 is 5 mm, and the difference in spacing from the inner side of the device 8 is 1.5 mm; the inner spacing of the electrical auxiliary component 7 is 3 mm, which exceeds 1 / 4 of the width of the device 8 body; the overall length of the electrical auxiliary component 7 is 26 mm, which is 2 mm less than the length of the device 8 body; the width of the 4 pins of the "H" shape of the electrical auxiliary component 7 is 1 mm.

[0059] (2) Use a screen printer to print solder paste on the PCB pad 61, and then use epoxy glue to stick the electrical auxiliary component 7 of step (1) to the central area of ​​the pad of the 3D-PLUS device 8.

[0060] When pasting the electrical auxiliary component 7, just apply a proper amount of epoxy glue to the crossbeam 72 of the "H"-shaped electrical auxiliary component 7, and then paste the electrical auxiliary component 7 to the center of the PCB pad. After pasting, gently press the electrical auxiliary component 7 to ensure that the electrical auxiliary component 7 and the substrate 6 are in a fitted state and the epoxy glue does not overflow to the PCB pad.

[0061] The epoxy adhesive used includes ECCOBOND 55 / 9, and the composition of ECCOBOND 55 / 9 includes ECCOBOND55 and Catalyst9. If the mass of ECCOBOND55 is 100 parts, the mass of Catalyst9 is 12 parts. The preparation method of the epoxy adhesive is: stir and mix ECCOBOND55 and Catalyst9 in an "8" shape to obtain the epoxy adhesive, and use the epoxy adhesive about 1.5 hours after the epoxy adhesive is prepared.

[0062] (3) The SOP64 packaged 3D-PLUS device 8 is mounted using a chip mounter. After the device 8 is mounted, the pin 81 is offset by less than 10% of the pad width. The electrical auxiliary component 7 is reflow soldered together with the device 8. The epoxy glue on the bottom of the electrical auxiliary component 7 is cured in a high temperature process to obtain a PCBA.

[0063] (4) After welding is completed, epoxy glue is injected at the bottom of the SOP64 packaged 3D-PLUS device 8. Insert the glue dispensing head into the bottom of the device 8, start the glue dispensing machine until the glue overflows, stop dispensing, and use the same method to inject epoxy glue to reinforce the other end of the device 8 to complete the bottom bonding reinforcement of the device 8. The epoxy glue is cured at room temperature for 24 hours.

[0064] The epoxy adhesive comprises ECCOBOND 55 / 9 and talcum powder. The ECCOBOND 55 / 9 comprises ECCOBOND55 and Catalyst9. Based on 100 parts by weight of ECCOBOND55, 12 parts by weight of Catalyst9 and 50 parts by weight of talcum powder are included. The preparation method of the epoxy adhesive comprises the following steps: mixing ECCOBOND55, Catalyst9 and talcum powder in an "8" shape to obtain the epoxy adhesive.

[0065] The epoxy glue is filled into a 6ml syringe using a small wooden stick. A glue injection hose is installed on the head of the syringe and the tail is connected to the glue dispensing machine.

[0066] Finally, the obtained PCBA board assembly was subjected to environmental testing in accordance with ECSS-Q-ST-70-08C. After the test and assessment, the metallographic structure of the solder joints showed no cracks, and the test results showed that the standard qualification criteria were met.

[0067] The implementation principle of this application is: the present invention designs suitable electrical auxiliary parts 7 for different SOP packaged 3D-PLUS devices 8, and pre-installs them before the devices 8 are electrically installed, so as to realize the automatic welding and high-reliability reinforcement of the SOP packaged 3D-PLUS devices 8, reduce the interlacing of welding and adhesive reinforcement processes of the SOP packaged 3D-PLUS devices 8 during the assembly process, improve the production efficiency of the devices 8 from manual welding to automatic welding, and at the same time improve the consistency and reliability of welding and reinforcement. This installation method can meet the more stringent use environment requirements of the product and ensure the reliability of the product.

[0068] Although the present invention is disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined by the claims of the present invention.

Claims

1. A mounting structure for SOP packaging 3D-PLUS devices for aerospace electronic products, characterized in that: include: A PCB substrate (6), wherein a PCB pad (61) is provided on the surface of the substrate (6), and an inner side (62) of the PCB pad is located between two rows of pads of the PCB pad (61); An electrical auxiliary component (7) connected to the surface of the PCB substrate (6) and located at the center of the inner side (62) of the PCB pad; The device (8) is located on a side of the electrical auxiliary component (7) facing away from the substrate (6); pins (81) connected to the device (8) are located on both sides of the electrical auxiliary component (7); the electrical auxiliary component (7) forms a separation area on the PCB substrate (6) that is separated from the area where the pins (81) are located; and reinforcing glue is provided between the device (8) and the PCB substrate (6) and in the separation area; The electrical auxiliary component (7) comprises two blocking rods (71) and a crossbeam (72) integrally connected between the two blocking rods (71), wherein the two blocking rods (71) are located on one side of the pin (81); The installation method for the SOP package 3D-PLUS device for aerospace electronic products comprises: Finishing solder paste printing on PCB pad (61); Paste the electrical auxiliary component (7) at the center of the inner side (62) of the PCB pad; The device (8) is mounted on the PCB pad (61), the device (8) is located on the side of the electrical auxiliary component (7) facing away from the PCB substrate (6), the pins (81) connected to the device (8) are located on both sides of the electrical auxiliary component (7), the electrical auxiliary component (7) forms a separation area on the PCB substrate (6) that is separated from the area where the pins (81) are located, and the electrical auxiliary component (7) is reflow soldered together with the PCB substrate (6) and the device (8) to obtain a PCBA assembly; Bottom adhesive reinforcement: injecting and curing the reinforcement glue between the bottom of the device (8) of the PCBA assembly and the PCB substrate (6) and in the separation area; The height difference between the electrical auxiliary component (7) and the height from the bottom of the device (8) body to the bottom of the pin (81) is 0.2 mm to 0.3 mm; the overall outer width of the electrical auxiliary component (7) is the spacing of the inner side (62) of the PCB pad minus 1.5 mm to 2 mm, and the spacing between the two blocking rods (71) of the electrical auxiliary component (7) is 1 / 4 to 1 / 3 of the width of the device (8); the overall length of the electrical auxiliary component (7) is the length of the device (8) body minus 1.5 mm to 2 mm; the width of the blocking rod (71) of the electrical auxiliary component (7) is 0.6 mm to 1 mm.

2. The mounting structure for SOP packaging 3D-PLUS devices for aerospace electronic products according to claim 1, characterized in that: The cross beam (72) is connected to the middle parts of the two blocking rods (71).

3. The mounting structure for SOP packaging 3D-PLUS devices for aerospace electronic products according to claim 1, characterized in that: The electrical auxiliary component (7) is adhered to the PCB substrate (6) by epoxy adhesive; after the device (8) is mounted, the pin (81) is offset by less than 10% of the width of the PCB pad (61).

4. The mounting structure for SOP packaging 3D-PLUS devices for aerospace electronic products according to claim 1, characterized in that: The bottom adhesive reinforcement adopts epoxy adhesive, the epoxy adhesive comprises ECCOBOND 55 / 9 and talcum powder filler, ECCOBOND 55 / 9 comprises ECCOBOND55 and Catalyst9, based on 100 parts by mass of ECCOBOND55, the mass fraction of Catalyst9 is 11.64-12.36 parts, and the mass fraction of talcum powder is 50 parts; The preparation method of the epoxy adhesive is as follows: ECCOBOND55, Catalyst9 and talcum powder are stirred and mixed evenly to obtain the epoxy adhesive.

5. The mounting structure for SOP packaging 3D-PLUS devices for aerospace electronic products according to claim 1, characterized in that: The bottom adhesive reinforcement method comprises: using an injection tool to inject epoxy glue into the bottom of the device (8) until the glue liquid fills the separation area between the device (8) and the PCB substrate (6), stopping the glue dispensing, and curing at room temperature.

6. The mounting structure for SOP packaging 3D-PLUS devices for aerospace electronic products according to claim 1, characterized in that: The electrical auxiliary component (7) and the PCB substrate (6) are fixed by epoxy glue.

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