Component mounting method suitable for different cavity depths

Abstract

The invention discloses an element mounting method suitable for different cavity depths. The method comprises the steps of soldering paste blade coating, silica gel head glue dipping, pattern transfer printing and element mounting. According to the invention, a customized silica gel head transfer printing mode is adopted, and the solder paste is transferred and coated according to a certain pattern, so that the problems of high difficulty, low precision and low efficiency of coating of the solder paste of mixed devices with different cavity depths are solved, and therefore, small-size element mounting is realized, and the requirements of aerospace, military and other application scenes on miniaturization, integration and light weight of the devices are met.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor packaging technology, and in particular to a component mounting method suitable for different cavity depths. Background Art

[0002] Hybrid devices have become a key technical approach to surpass Moore's Law in the post-Moore era due to their advantages of small size, light weight, and high system integration, and are gradually being applied to aerospace, weapons, and other fields. Hybrid devices usually use screen printing technology to coat solder paste on the pad surface and finally realize component mounting. However, for ceramic airtight hybrid devices with different cavity depths, it is difficult to realize solder paste printing through a flat steel mesh. If a folded steel mesh is used, there are a series of problems such as difficulty in steel mesh processing, difficulty in scraping, and solder paste contamination of the device cavity when facing small-sized hybrid devices; if a pin transfer method is used, it cannot meet the market development trend of miniaturization, multiple varieties, and small batches of hybrid devices, and pin transfer has defects such as difficulty in controlling the amount of glue applied, low coating quality and control accuracy; and the use of solder paste spraying technology faces problems such as poor deep cavity operation capability and high equipment cost. Therefore, it is urgent to develop a component mounting method suitable for different cavity depths that can take into account product adaptability, simplicity of operation, production efficiency, and product quality at the same time, and ensure that aerospace and military hybrid devices can achieve high reliability and airtight packaging. Summary of the invention

[0003] The technical problem solved by this application is: to overcome the shortcomings of the prior art and provide a component mounting method suitable for different cavity depths, in which the pad printing rubber head dips the solder paste with printed patterns on the surface of the pad printing steel sheet at the corresponding position, and transfers the solder paste to the corresponding hybrid device pad at the corresponding position, thereby achieving solder paste coating on the surface of the hybrid device and completing component mounting in the subsequent process, which can meet the adaptability, simplicity of operation, production efficiency and product quality of hybrid device packaging products, and provide strong technical guarantee for high-reliability and airtight packaging of aerospace and military hybrid devices. It overcomes the problem that it is difficult to achieve high-efficiency, high-precision and high-quality solder paste printing for hybrid devices with different cavity depths using methods such as screen printing, pin transfer, and solder paste spraying technology.

[0004] The technical solutions provided by this application are as follows:

[0005] A component mounting method applicable to different cavity depths, the steps comprising:

[0006] Step S1: Customize a steel sheet with printed patterns according to the pad layout of the hybrid device to be printed, take an appropriate amount of solder paste and place it on the steel sheet, use a scraper to scrape the solder paste on the corresponding pattern, and scrape repeatedly until the solder paste is evenly distributed in all printed patterns.

[0007] Step S2: Place a pad printing rubber head that matches the product to be printed on the pattern to be printed with solder paste on the surface, move it downward perpendicular to the pad printing steel sheet, and continue to press downward for a certain distance after the silicone head contacts the steel sheet and evenly dip the solder paste.

[0008] Step S3: Place the dipped pad printing head on the hybrid device with matching pattern, align with the pad printing position, move downward, and press down a certain amount after contacting the pad surface of the hybrid device to complete the pattern transfer.

[0009] Step S4: Mount components on the pads coated with solder paste.

[0010] Furthermore, in step S1, the steel sheet is a pad printing steel sheet made of stainless steel, with a length of 10 cm to 25 cm, a width of 5 cm to 15 cm, and a thickness of 0.5 mm to 1 mm.

[0011] Furthermore, in step S1, the printed pattern on the surface of the steel sheet is processed by laser etching or chemical etching, the etching depth of the printed pattern on the steel sheet is 24 μm to 120 μm, and the size is 80-90% of the area of ​​the corresponding device pad.

[0012] Further, in step S1, the solder paste includes but is not limited to Sn-Pb solder paste, Sn-Ag-Cu solder paste, Sn-Bi solder paste, Sn-Ag solder paste, Sn-Cu solder paste, etc.

[0013] Furthermore, in step S2, the pad printing rubber head includes a base and a silicone head.

[0014] Further, in step S2, the base material includes but is not limited to metal, plastic, wood, ceramic, etc., the silicone head has a length of 1cm to 10cm, a width of 0.5cm to 5cm, a height of 1cm to 20cm, a hardness of 4H to 6H, and an effective transfer area of ​​the silicone head is 75-85% of the end surface area.

[0015] Further, in step S2, the cavity depth of the mixing device is ≤2cm, and the length, width and height ratio of the silicone head is 2:1:3; 2<cavity depth ≤3.5cm, and the length, width and height ratio of the silicone head is 2:1:3.5; 3.5<cavity depth ≤5cm, and the length, width and height ratio of the silicone head is 1:0.5:2, and its hardness is 4H~6H, and the effective transfer area of ​​the silicone head is 80% of the end surface area.

[0016] Furthermore, in step S2, the pad printing rubber head is aligned with the printed pattern at a fixed position by manual alignment, tooling alignment, automated equipment alignment, etc., and the pressing amount is 0.5mm to 5mm, which is 50 times the etching depth of the steel sheet printed drawing.

[0017] Further, in step S3, the hybrid device is made of metal or ceramic, and is airtightly packaged by parallel seam welding or melting sealing. The cavity depth is 0.5 cm to 5 cm, and the interior of the cavity includes but is not limited to resistor pads, capacitor pads, inductor pads, power chip pads, etc.

[0018] Furthermore, in step S3, the graphic printing is realized by manual alignment, tooling alignment, automated equipment alignment, etc., and the pressing amount for aligning with the pad graphic at a fixed position is 0.5mm to 6mm, which is 1 to 1.2 times the pressing amount when dipping the solder paste.

[0019] Furthermore, in step S4, the mounting structure includes components, solder paste and pads.

[0020] Furthermore, in step S4, the components include but are not limited to resistors, capacitors, inductors, etc., and the components' welding terminal components include but are not limited to SnPb, Sn, Ag, etc.

[0021] Further, in step S4, the thickness of the solder paste after being transferred to the surface of the pad is 20μm to 120μm; while ensuring that all the solder paste in the printed pattern is taken out, the etching depth of the printed pattern is ≤ the paste pressing amount ≤ the pattern printing pressing amount, the paste pressing amount is the pressing amount of the pad printing rubber head relative to the surface of the steel plate when taking the solder paste from the steel sheet, the pattern printing pressing amount is the pressing amount of the pad printing rubber head relative to the surface of the pad, and the thickness of the solder paste after being transferred to the pad is the etching depth × (paste pressing amount ÷ pattern printing pressing amount).

[0022] In summary, this application at least includes the following beneficial technical effects:

[0023] Solder paste coating is carried out by transferring customized patterns with a pad printing head, which effectively solves the problem that screen printing, pin transfer, solder paste spraying technology and other technologies are difficult to meet the requirements of solder paste coating on the surface of pads of hybrid devices with different cavity depths. At the same time, this method can ensure the uniformity and accuracy of solder paste coating thickness. It is suitable for hybrid devices with small device size, large number of components and high integration. Compared with pin transfer and solder paste spraying technology, it has obvious advantages in production efficiency, meets the high-reliability packaging requirements of hybrid devices in special fields such as aerospace and military, is suitable for large-scale mass production, and has good engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of a pad printing steel sheet;

[0025] Figure 2 This is the structure diagram of the pad printing rubber head;

[0026] Figure 3 is a schematic diagram of a hybrid device;

[0027] Figure 4 Schematic diagram of component mounting structure. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0029] The present application embodiment discloses a component mounting method applicable to different cavity depths. Figure 3 is a schematic diagram of a hybrid device. Figure 3 The hybrid device 3 includes a resistor pad 31, a capacitor pad 32, an inductor pad 33, and a power chip pad 34. Since the resistor pad 31, the capacitor pad 32, the inductor pad 33, and the power chip pad 34 are all located at the same depth at the bottom of the hybrid device 3 cavity, they are divided into a waiting area.

[0030] According to the pad layout of the area to be welded, a printed pattern is made on the steel sheet, such as Figure 1 The surface of the pad printing steel sheet 1 is processed with a printed pattern 11. The printed pattern 11 is composed of a plurality of grooves corresponding to the pads one by one, the groove layout of the printed pattern 11 is consistent with the pad layout, and the grooves of the printed pattern are used to fill solder paste.

[0031] The material of the pad printing steel sheet 1 is stainless steel, the surface printed pattern 11 is processed by chemical etching, the etching depth of the printed pattern is 60μm, and the solder paste is Sn-Pb solder paste. The corresponding advantage is that the chemically etched pattern groove is smooth inside and has few burrs, which is conducive to solder paste scraping and filling and pad printing rubber head dipping.

[0032] When the pad at the bottom of the hybrid device 3 is at different distances from the cavity opening end of the hybrid device 3, that is, the pad depth at the bottom of the hybrid device 3 is different, the bottom of the hybrid device 3 is divided into multiple areas to be welded according to different depths, and each area to be welded is a continuous area.

[0033] The plane perpendicular to the cavity depth direction of the hybrid device 3 is the XOY plane, and the two directions perpendicular to each other on the XOY plane are the X direction and the Y direction. The pad printing rubber head 2 of this patent is used for transfer printing in the area to be soldered with a maximum size of not less than 0.5 mm in the X direction and the Y direction. The solder paste is printed by needle transfer in the area to be soldered with a maximum size of less than 0.5 mm in the X direction and the Y direction.

[0034] A component mounting method applicable to different cavity depths, the steps comprising:

[0035] Step S1: Take an appropriate amount of Sn-Pb solder paste and place it on one side of the printed pattern on the steel sheet, and use a scraper to scrape the solder paste from one side to the other side of the printed pattern at a uniform speed, and scrape repeatedly until the solder paste evenly fills the groove of the printed pattern 11, and there is no solder paste residue in the area outside the printed pattern 11. The corresponding benefit is that it is conducive to the full transfer of the printed pattern 11 and avoids the contamination of the device to be transferred by excess solder paste.

[0036] Figure 2 This is the structure diagram of the pad printing rubber head. Figure 2 The pad printing rubber head 2 comprises a base 21 and a silicone head 22 connected to the base 21. The height of the pad printing rubber head 2 is greater than the depth of the corresponding area to be welded.

[0037] The base 21 is made of wood, and the silicone head is 3 cm long, 1.5 cm wide, 4.5 cm high, and has a hardness of 4H. The end surface of the silicone head 22 away from the base 21 is a transfer surface, and the transfer surface is used to contact the printed pattern 11. The middle part of the transfer surface is convex and has an arc-shaped surface. The corresponding benefit is that it is conducive to the rubber head to maintain a good deformation state and ensure the accuracy of the solder paste thickness of the transfer pattern. The amount of movement of the transfer surface after contacting the surface of the area to be welded is 0.5 mm to 5 mm. After the transfer surface continues to move downward to the amount of movement after contacting the surface of the area to be welded, the contact area between the transfer surface and the area to be welded is the effective transfer area, and the effective transfer area of ​​the transfer surface is 80% of the total area of ​​the transfer surface.

[0038] Step S2: Use positioning tooling to assist positioning, place the pad printing rubber head 2 on the pattern to be printed with solder paste on the surface, move it downward at a constant speed perpendicular to the pad printing steel sheet, and continue to move downward 3mm after the silicone head contacts the pad printing steel sheet 1 and evenly dips the solder paste. The corresponding benefits are that it is conducive to fully dipping the solder paste and the alignment accuracy of the pattern transfer.

[0039] The material of the hybrid device 3 is ceramic, and the airtight packaging is carried out by parallel seam welding, and the cavity depth is 2 cm. The corresponding benefit is that it is beneficial to the electrical protection of the internal components of the hybrid device 3 and avoids the electrical performance failure caused by excessive water vapor content.

[0040] Step S3: Use positioning tooling to assist positioning, place the pad printing rubber head 2 with the pattern on top of the hybrid device with matching pattern, align with the pad printing position, move downward, and press 3.6mm after contacting the device pad surface to complete the pattern transfer. The corresponding benefit is that it is conducive to the spread area and thickness control of the transferred solder paste on the pad surface.

[0041] Figure 4 Figure 1 is a schematic diagram of the component mounting structure. Figure 4 As described above, the component mounting structure 4 includes components 41 , solder paste 42 , and pads 43 .

[0042] The components 41 include resistors, capacitors, and inductors, the component welding ends are made of SnPb, and the thickness of the solder paste 42 is 50 μm. The corresponding benefit is that it is conducive to the qualified appearance and welding strength of the components.

[0043] Step S4: accurately mount the ends of the resistor, capacitor, and inductor on the pads coated with solder paste, and ensure that the soldering ends are in full contact with the solder paste. The corresponding benefit is that it is conducive to improving the one-time soldering yield.

[0044] The contents not described in detail in this application specification belong to the common knowledge of those skilled in the art.

[0045] The present application is described in detail above in conjunction with specific implementation methods and exemplary examples, but these descriptions cannot be understood as limiting the present application. Those skilled in the art understand that, without departing from the spirit and scope of the present application, a variety of equivalent replacements, modifications or improvements can be made to the technical solution of the present application and its implementation methods, all of which fall within the scope of the present application. The scope of protection of the present application shall be subject to the attached claims.

Claims

1. A component mounting method suitable for different cavity depths, characterized in that: include: S1: producing a corresponding printed pattern (11) on a steel sheet (1) according to the layout of the pads of the hybrid device (3) to be printed, wherein the printed pattern (11) is composed of a plurality of grooves corresponding to the pads one by one, and the grooves of the printed pattern are used to fill solder paste; S2: placing the pad printing rubber head (2) above the printed pattern (11) coated with solder paste, and moving it downward perpendicularly to the pad printing steel sheet (1). After the pad printing rubber head (2) contacts the steel sheet (1), continue to squeeze downward to dip the solder paste; S3: placing the pad printing head (2) dipped in solder paste above the pad layout of the hybrid device (3) to be printed, moving the pad printing head (2) downward and, after contacting the pad surface of the hybrid device, continuing to move downward according to the movement amount, then the pad printing head moves away from the hybrid device (3), and the pad surface is coated with solder paste; S4: Mounting the soldering terminal of the component (41) on the soldering pad coated with solder paste.

2. A component mounting method applicable to different cavity depths according to claim 1, characterized in that: In S1, a steel sheet with a printed pattern is manufactured according to the pad layout of the hybrid device to be printed, including: the pad is located at the bottom of the cavity of the hybrid device to be printed, and the bottom of the hybrid device to be printed is divided into a plurality of welding areas according to the depth of the pad; and a printed pattern is manufactured on the steel sheet according to the pad layout of each welding area.

3. A component mounting method applicable to different cavity depths according to claim 2, characterized in that: The plane perpendicular to the cavity depth direction of the hybrid device (3) is the XOY plane, the two directions perpendicular to each other on the XOY plane are the X direction and the Y direction, and the maximum size of each area to be welded in the X direction and the Y direction is not less than 0.5 mm.

4. The component mounting method applicable to different cavity depths according to claim 3, characterized in that: The height of the pad printing rubber head (2) is greater than the depth of the corresponding area to be welded.

5. The component mounting method applicable to different cavity depths according to claim 1, characterized in that: The printed pattern (11) on the surface of the steel sheet is processed by laser etching or chemical etching; the etching depth of the groove of the printed pattern (11) is 24 μm to 120 μm.

6. The component mounting method applicable to different cavity depths according to claim 1, characterized in that: The size of each groove is 80-90% of the area of ​​the corresponding pad of the hybrid device (3), and the groove is directly opposite to the center point of the corresponding pad.

7. The component mounting method applicable to different cavity depths according to claim 1, characterized in that: The pad printing rubber head (2) comprises a base (21) and a silicone head (22) connected to the base (21); the hardness of the silicone head (22) is 4H-6H; the end surface of the silicone head (22) away from the base (21) is a transfer surface; the transfer surface is used to contact the printed pattern (11); the middle part of the transfer surface is convex and presents an arc-shaped surface; the amount of movement of the transfer surface further downward after contacting the surface of the area to be welded is 0.5mm-5mm.

8. The component mounting method applicable to different cavity depths according to claim 1, characterized in that: After the transfer surface contacts the surface of the area to be welded and continues to move downward to the moving amount, the contact area between the transfer surface and the area to be welded is the effective transfer area, and the effective transfer area of ​​the transfer surface is 75-85% of the total area of ​​the transfer surface.

9. The component mounting method applicable to different cavity depths according to claim 1, characterized in that: The solder paste includes but is not limited to Sn-Pb solder paste, Sn-Ag-Cu solder paste, Sn-Bi solder paste, Sn-Ag solder paste or Sn-Cu solder paste.

10. The component mounting method applicable to different cavity depths according to claim 1, characterized in that: The components (41) include but are not limited to resistors, capacitors or inductors; the components (41) include but are not limited to SnPb, Sn or Ag.

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