Steel mesh trepanning structure and steel mesh trepanning structure selection method
By designing a structure with different lengths of the epitaxial parts of multiple pin holes on the steel mesh, the problem of insufficient tin crawling height of the pad during the soldering process of integrated circuit modules is solved, and the welding strength and stability are improved.
Patent Information
- Application Number
- CN202411801112.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-03-14
AI Technical Summary
The existing steel mesh open hole structure is difficult to meet the welding needs of integrated circuit modules, resulting in insufficient tin crawling height of the solder pads on the side pins of the module during the welding process, resulting in poor welding or insufficient welding strength.
A steel mesh hole structure is designed, in which each pin hole includes a bottom part and an epitaxial part. The length of the epitaxial part of the multiple pin holes is not exactly the same. By flexibly controlling the amount of solder paste in the epitaxial part of the pin pad, it can adapt to the warping and deformation problems of the integrated circuit module.
By adjusting the length of the pin opening epitaxial part, the welding strength of the pin pads on the side of the integrated circuit module can be improved, the stability and quality of welding can be enhanced, and the defective problems such as dummy welding can be avoided.
Smart Images
Figure CN119629874A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of surface mounted technology (SMT), and in particular to a steel mesh opening structure and a steel mesh opening structure selection method. Background Art
[0002] A steel mesh (also called a template) is a flat mold used in the SMT printing process to print solder paste or glue. It can transfer an accurate amount of solder paste through the openings on the steel mesh to the corresponding pads on the printed circuit board (PCB) for subsequent welding. However, the existing steel mesh opening structure is difficult to meet the welding requirements of integrated circuit modules, resulting in insufficient solder climbing height of the module side pin pads during welding, which in turn causes the module side pin pads to not form welding or insufficient welding strength. Summary of the invention
[0003] The present application provides a steel mesh opening structure and a steel mesh opening structure selection method, which can improve the welding strength of the side pin pads of the integrated circuit module.
[0004] In a first aspect, a steel mesh opening structure is provided, comprising a plurality of pin openings corresponding to a plurality of pin pads of an integrated circuit module; each pin opening comprises a pin opening bottom portion corresponding to a bottom pin pad of the integrated circuit module and a pin opening extension portion corresponding to a side pin pad of the integrated circuit module; the lengths of the pin opening extension portions of the plurality of pin openings are not exactly the same.
[0005] The steel mesh opening structure provided in the embodiment of the present application controls the amount of solder paste at the pin pads on the side of the integrated circuit module by changing the length of the extension part of the pin opening on the steel mesh, that is, the amount of solder paste on the extension part of different pin pads can be different. This embodiment can adapt to the warping and deformation problems of the integrated circuit module by flexibly controlling the amount of solder paste on the extension part of the pin pad, thereby improving the welding strength of the pin pads on the side of the integrated circuit module.
[0006] In combination with the first aspect, in certain implementations of the first aspect, the lengths of the pin opening extension portions corresponding to the side pin pads on the same side of the integrated circuit module are distributed in a gradient manner; wherein the length of the pin opening extension portion corresponding to the side pin pad located in the middle is smaller than the lengths of the pin opening extension portions corresponding to the side pin pads located on both sides.
[0007] Through the above implementation, the steel mesh can gradually increase the amount of solder paste on the side pin pads near the corners of the module, making it more than the amount of solder paste on the side pin pads near the middle of the surface. Furthermore, during the welding process, the side pin pads relatively closer to the corners can form a higher welding strength than those relatively closer to the middle of the surface. In the case of upward warping of the module, the steel mesh opening structure provided by the above implementation can strengthen the welding strength at the four corners of the module, increase the tin creeping height, and avoid poor welding problems such as cold solder joints.
[0008] In combination with the first aspect, in certain implementations of the first aspect, the lengths of the pin opening extension portions corresponding to the side pin pads on the same side of the integrated circuit module are distributed in a gradient manner; wherein the length of the pin opening extension portion corresponding to the side pin pad located in the middle is greater than the length of the pin opening extension portion corresponding to the side pin pads located on both sides.
[0009] Through the above implementation, the steel mesh can gradually increase the amount of solder paste on the side pin pads near the middle of the surface of the module, making it more than the amount of solder paste on the side pin pads near the corners. Furthermore, during the welding process, the side pin pads relatively closer to the middle of the surface can form a higher welding strength than those relatively closer to the corners. In the case of downward warping of the module, the steel mesh opening structure provided by the above implementation can strengthen the welding strength of the middle of the module, increase the tin creeping height, and avoid poor welding problems such as cold solder joints.
[0010] In combination with the first aspect, in certain implementations of the first aspect, the integrated circuit module is disposed on a PCB, and an outward extension length of the pin opening is greater than or equal to 0.85 mm and less than or equal to 1.00 mm; the outward extension length is the length of the portion of the pin opening extending out of the corresponding PCB pin pad.
[0011] The above implementation method can further improve the welding strength of the pin pads on the side of the module by increasing the outward extension length of the pin opening to increase the amount of solder paste corresponding to the pin pads on the side of the module.
[0012] In combination with the first aspect, in certain implementations of the first aspect, there is a step portion protruding from the surface of the steel mesh around the pin opening, and the thickness of the pin opening is 0.18 mm.
[0013] The above embodiment increases the thickness of the pin opening by means of the step portion, thereby increasing the amount of solder paste corresponding to the module side pad, and can further improve the welding strength of the module side pin pad.
[0014] In combination with the first aspect, in certain implementations of the first aspect, the steel mesh structure further includes a bottom opening corresponding to the bottom pad of the integrated circuit module, and the area of the bottom opening is 70%-80% of the area of the bottom pad of the PCB.
[0015] In the above embodiment, the structural design of the openings at the bottom of the steel mesh can prevent the bottom of the integrated circuit module from being raised due to excessive solder paste, affecting the welding performance of other areas such as pin pads, or causing poor solder joints at the bottom of the module due to insufficient solder paste.
[0016] In a second aspect, a method for selecting a steel mesh opening structure is provided, including obtaining the warpage of an integrated circuit module; if the warpage is greater than or equal to a warpage threshold, using a steel mesh having a steel mesh opening structure in the first aspect or each implementation of the first aspect; if the warpage is less than the warpage threshold, using a conventional open-pore steel mesh; in a conventional open-pore steel mesh, the lengths of multiple pin openings corresponding to multiple pin pads of the integrated circuit module are the same.
[0017] The above implementation method can more flexibly and accurately improve the welding strength of the side pin pads of integrated circuit modules with different warping degrees by judging the warping degree of the integrated circuit module and selecting and using a corresponding steel mesh opening structure accordingly.
[0018] In combination with the second aspect, in certain implementations of the second aspect, if the warping degree of the areas near the two sides of the same side of the integrated circuit module is greater than the warping degree of the areas near the middle, a steel mesh is used in which the lengths of the extension parts of the pin openings corresponding to the side pin pads on the same side of the integrated circuit module are gradiently distributed, and the lengths of the extension parts of the pin openings corresponding to the side pin pads in the middle are smaller than the lengths of the extension parts of the pin openings corresponding to the side pin pads on the two sides.
[0019] In combination with the second aspect, in certain implementations of the second aspect, if the warping degree of the areas near the two sides of the same side of the integrated circuit module is smaller than the warping degree near the middle area, a steel mesh is used in which the lengths of the extension parts of the pin openings corresponding to the side pin pads on the same side of the integrated circuit module are gradiently distributed, and the lengths of the extension parts of the pin openings corresponding to the side pin pads in the middle are larger than the lengths of the extension parts of the pin openings corresponding to the side pin pads on the two sides.
[0020] In the above embodiment, according to the specific warping type of the integrated circuit module, such as upward warping or downward warping, a matching steel mesh opening structure, that is, a matching gradient distribution type of the steel mesh pin opening extension, is selected, which can more specifically improve the welding strength of the module side pin pad. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 It is a schematic diagram of the structure of the integrated circuit module provided in the embodiment of the present application.
[0022] Figure 2 It is a schematic diagram of a partially enlarged structure of another integrated circuit module provided in an embodiment of the present application.
[0023] Figure 3 It is a schematic diagram of the integrated circuit module provided in the embodiment of the present application during welding.
[0024] Figure 4 yes Figure 3 A partial enlarged view of area A.
[0025] Figure 5 It is a top view schematic diagram of the steel mesh opening structure provided in an embodiment of the present application.
[0026] Figure 6 It is a top view schematic diagram of another steel mesh opening structure provided in an embodiment of the present application.
[0027] Figure 7 yes Figure 6 A partial enlarged view of area B.
[0028] Figure 8 The steel mesh provided in the embodiment of the present application is Figure 6 Schematic diagram of a partial enlargement of the cross section along the CC′ direction.
[0029] Fig. 9 It is a top view schematic diagram of another steel mesh opening structure provided in an embodiment of the present application.
[0030] Fig.10 It is a schematic diagram of the method for selecting the steel mesh opening structure provided in an embodiment of the present application. DETAILED DESCRIPTION
[0031] The technical solution in this application will be described below in conjunction with the accompanying drawings.
[0032] In the description of this application, it should be noted that the terms "first", "second", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features.
[0033] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium.
[0034] The directional terms mentioned in the embodiments of the present application, such as "up", "down", "left", "right", "inside", "outside", etc., are only referenced to the directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, unless otherwise specified in the present application, the "multiple" described in the present application refers to two or more. "Vertical" is not vertical in the strict sense, but is within the allowable error range. "Parallel" is not parallel in the strict sense, but is within the allowable error range.
[0035] In the description of the embodiments of the present application, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.
[0036] In the embodiments of the present application, "and / or" is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.
[0037] The present application relates to a steel mesh opening structure, and the steel mesh with the structure can be used for module welding in SMT. SMT is an electronic assembly technology that mounts pinless or short-lead surface mounted devices (surface mounted devices, SMD) on the surface of a PCB or other substrate and welds them by reflow soldering or dip soldering.
[0038] The integrated circuit module involved in the embodiments of the present application is also called an embedded module, which integrates the chip and peripheral hardware circuits on a PCB, and then performs processes such as function redevelopment and shell packaging on this basis to finally form a semiconductor integrated circuit module with integrated specific functions, such as a wireless communication module.
[0039] The shape and size of the pad of the integrated circuit module are related to its model. Integrated circuit modules of the same model have the same pad shape and size design. Similarly, integrated circuit modules of the same model also have the same PCB pad design. The module pad and PCB pad positions correspond and the sizes are related.
[0040] Figure 1 is a schematic diagram of the structure of the integrated circuit module provided in the embodiment of the present application. Figure 1 As shown, the integrated circuit module 1 may include a first circuit board 12 and a packaging shell 11 ( Figure 1 (not shown in the figure), the first circuit board 12 includes a plurality of pin pads 123 extending from the bottom surface 121 to the side surface 122, wherein the bottom surface 121 may be the surface where the integrated circuit module 1 is welded to other board surfaces, and the side surface 122 may be the surface of the first circuit board 12 that is perpendicular to the bottom surface 121. Accordingly, the portion of the pin pads 123 located on the bottom surface 121 may be the bottom pin pads 1211, and the portion located on the side surface 122 may be the side pin pads 1221. It can be understood that the pin pads 123 of the first circuit board 12 may also be referred to as the pin pads 123 of the integrated circuit module 1.
[0041] In some embodiments, the pin pads of the integrated circuit module may also be stamp hole pads. Figure 2 , Figure 2 It is a partial enlarged view of a pin pad 123 in another integrated circuit module provided in an embodiment of the present application. The side 122 of the first circuit board 12 may include a semi-hole stamp hole 1222, and the metal side wall of the stamp hole 1222 is the side pin pad 1221 of the module, and the side pin pad 1221 is recessed into the side 122 of the integrated circuit module 1.
[0042] Compared with chip-type SMD components, the size of integrated circuit modules is larger, and its thickness is about 10 times that of chips. In addition, the plane size may reach 30mm×50mm, 50mm×50mm, etc. Correspondingly, the flatness of integrated circuit modules is relatively poor, and the possibility of warping and deformation during packaging and welding is high. The above factors have an adverse effect on the welding of integrated circuit modules.
[0043] During the module packaging process, due to the mismatch of the coefficient of thermal expansion (CTE) of adjacent materials such as silicon, molding materials, copper, etc. in the multi-layer material, uneven stress points are caused, resulting in thermal deformation during the packaging process, that is, package warping, which will affect the external connection performance and thermal performance. Therefore, it can be seen that the warped part of the module may affect the welding performance of the module, such as causing a lower tin creep height of the side pin pad, and the higher the warping degree, the more serious the impact.
[0044] Figure 3 This is a schematic diagram of the integrated circuit module 1 provided in the embodiment of the present application when it is welded. In some embodiments, such as Figure 3As shown, the first circuit board 12 of the integrated circuit module 1 with package warping is soldered to the corresponding position on the second circuit board 2 through the solder paste 3, that is, the integrated circuit module 1 is arranged on the PCB2. Figure 4 yes Figure 3 A partial enlarged view of the A area in the middle shows that during the welding process, liquid tin climbs along the surface of the side pin pad 1221, and the tin climbing height d1 can affect the welding quality and welding state of the module. However, under the relevant steel mesh opening design scheme, the integrated circuit module 1 may further warp due to thermal expansion during the high temperature 245-250℃ welding process, resulting in the tin climbing height d1 on its side pin pad 1221 being less than 25% of the thickness d2 of the integrated circuit module 1 required by the standard, that is, d1<25%*d2, which in turn causes the side pin pad 1221 of the integrated circuit module 1 to not form a weld or the welding strength is insufficient.
[0045] Figure 5 A schematic top view of a steel mesh opening structure provided in an embodiment of the present application is shown in FIG. Figure 5 As shown, the steel mesh 4 may include a plurality of pin openings 41 corresponding to a plurality of pin pads of the integrated circuit module; each pin opening 41 includes a pin opening bottom portion 411 corresponding to the bottom pin pad of the integrated circuit module and a pin opening extension portion 412 corresponding to the side pin pad of the integrated circuit module; the lengths d1 of the pin opening extension portions 412 of the plurality of pin openings 41 are not exactly the same.
[0046] The pin openings of the steel mesh can be arranged on the outer contour line 13 of the top view of the integrated circuit module, that is, at least two parallel sides of the top view contour line 13 of the first circuit board. The contour line 13 can be the boundary between the bottom part 411 of the pin opening in the steel mesh 4 and the extension part 412 of the pin opening.
[0047] The steel mesh opening structure provided in the embodiment of the present application controls the amount of solder paste at the pin pads on the side of the integrated circuit module by changing the length of the extension part of the pin opening on the steel mesh, that is, the amount of solder paste on the extension part of different pin pads can be different. This embodiment can adapt to the warping and deformation problems of the integrated circuit module by flexibly controlling the amount of solder paste on the extension part of the pin pad, thereby improving the welding strength of the pin pads on the side of the integrated circuit module.
[0048] Warping can occur upward (edge warping upward) or downward (edge warping downward). When warping upward, the warping degree of the area near the corner of the side of the integrated circuit module is higher than that of the area near the middle of the surface, which can also be understood as the welding performance of the side pin pad near the corner is worse than that near the middle of the surface; when warping downward, the warping degree of the area near the middle of the side of the integrated circuit module is higher than that near the corner, which can also be understood as the welding performance of the side pin pad near the middle of the surface is worse than that near the corner.
[0049] Alternatively, if Figure 5 As shown, the length d1 of the pin opening extension part 412 corresponding to the side pin pad on the same side of the integrated circuit module can form a gradient distribution (or gradual distribution); wherein, the length d1a of the pin opening extension part 412 corresponding to the side pin pad located in the middle is smaller than the length d1b of the pin opening extension part 412 corresponding to the side pin pads located on both sides.
[0050] Through the above implementation, the steel mesh can gradually increase the amount of solder paste on the side pin pads near the corners of the module, making it more than the amount of solder paste on the side pin pads near the middle of the surface. Furthermore, during the welding process, the side pin pads relatively closer to the corners can form a higher welding strength than those relatively closer to the middle of the surface. In the case of upward warping of the module, the steel mesh opening structure provided by the above implementation can strengthen the welding strength at the four corners of the module, increase the tin creeping height, and avoid poor welding problems such as cold solder joints.
[0051] Figure 6 is a top view schematic diagram of another steel mesh opening structure provided in an embodiment of the present application. Optionally, as Figure 6 As shown, the length d1 of the pin opening extension part 412 corresponding to the side pin pad on the same side of the integrated circuit module can form a gradient distribution (or gradual distribution); wherein, the length d1a of the pin opening extension part 412 corresponding to the side pin pad located in the middle is greater than the length d1b of the pin opening extension part 412 corresponding to the side pin pads located on both sides.
[0052] Through the above implementation, the steel mesh can gradually increase the amount of solder paste on the side pin pads near the middle of the surface of the module, making it more than the amount of solder paste on the side pin pads near the corners. Furthermore, during the welding process, the side pin pads relatively closer to the middle of the surface can form a higher welding strength than those relatively closer to the corners. In the case of downward warping of the module, the steel mesh opening structure provided by the above implementation can strengthen the welding strength of the middle of the module, increase the tin creeping height, and avoid poor welding problems such as cold solder joints.
[0053] refer to Figure 7 , Figure 7 yes Figure 6 A partial enlarged view of region B in FIG. Figure 7 As shown, the pin opening 41 on the steel mesh can be in the shape of a square with rounded corners at both ends. In some embodiments, the pin opening can also be in the shape of a rectangle.
[0054] Optionally, the integrated circuit module can be set on the PCB, and the outward extension length d2 of the pin opening 41 is greater than or equal to 0.85mm and less than or equal to 1.00mm. The outward extension length d2 can be the length of the portion of the pin opening 41 extending out of the corresponding PCB pin pad.
[0055] The PCB pin pad refers to the target PCB during welding (in the embodiment of the present application, the target PCB can be Figure 3 The pads on the second circuit board 2) shown in FIG. 2 correspond to the pin pads of the integrated circuit module, that is, the pin pads on the integrated circuit module correspond to the PCB pin pads on the second circuit board. The above two also have corresponding relationships with the pin openings on the steel mesh. Figure 7 The PCB pin pad outline 42 in the figure may be a pin pad on the second circuit board ( Figure 7 The contour lines of the corresponding positions on the steel mesh (not shown) are shown.
[0056] In the related art, the outward expansion length of the steel mesh pin opening is usually 0.5mm. Due to the factors such as the large thickness, poor flatness and high warpage of the integrated circuit module, the welding strength of the side pin pad is usually insufficient. The above embodiment can further improve the welding strength of the side pin pad of the module by increasing the outward expansion length of the pin opening to increase the amount of solder paste corresponding to the side pin pad of the module.
[0057] Optionally, the width d4 of the bottom portion of the pin opening is smaller than the width d3 of the PCB pin pad; and the width d5 of the extended portion of the pin opening is larger than the width d3 of the PCB pin pad.
[0058] The pin opening on the steel mesh is slightly narrower than the PCB pin pad at the bottom of the module, which can avoid the formation of tin beads or tin links due to excessive solder paste at the pin pad on the bottom of the module during welding, resulting in poor welding; and the extended part is slightly wider than the PCB pin pad, which can increase the amount of solder paste corresponding to the pin pad on the side of the module and improve its welding strength.
[0059] Figure 8 The steel mesh structure provided in the embodiment of the present application is Figure 6 A partial enlarged schematic diagram of the cross section in the CC′ direction, optionally, as Figure 8 As shown, there may be a step portion 413 protruding from the surface of the steel mesh 4 around the pin opening 41, and the thickness d6 of the pin opening 41 may be 0.18 mm.
[0060] In the related art, the thickness of the steel mesh pin opening is usually 0.15mm. Due to the factors such as the large thickness, poor flatness and high warpage of the integrated circuit module, the welding strength of the side pin pad is usually insufficient. The above embodiment can further improve the welding strength of the side pin pad of the module by increasing the thickness of the pin opening to increase the amount of solder paste corresponding to the side pad of the module.
[0061] In some embodiments, the step portion 413 protrudes from the upper surface of the steel mesh 4, that is, the surface in contact with the scraper, and the thickness d6 of the pin opening 41 can be increased by the step portion 413. This method can also be called a local thickening process (step-up). For example, the base thickness d7 of the steel mesh 4 can be 0.10 mm, the thickness of the step portion 413 can be 0.08 mm, and the thickness d6 of the pin opening 41 can be 0.18 mm.
[0062] Fig. 9 A schematic top view of another steel mesh opening structure provided in an embodiment of the present application. Fig. 9 As shown, the steel mesh 4 may also include a bottom opening 43 corresponding to the bottom pad of the integrated circuit module. Correspondingly, the second circuit board may also include a PCB bottom pad corresponding to the bottom pad. The shape and size of the bottom opening 43 in the steel mesh 4 are related to the PCB bottom pad, and the area of the bottom opening 43 may be 70%-80% of the area of the PCB bottom pad. Optionally, there may also be a step portion protruding from the surface of the steel mesh 4 around the bottom opening 43, and the thickness of the bottom opening 43 may be 0.12 mm.
[0063] In the above embodiment, the structural design of the openings at the bottom of the steel mesh can prevent the bottom of the integrated circuit module from being raised due to excessive solder paste, affecting the welding performance of other areas such as pin pads, or causing poor solder joints at the bottom of the module due to insufficient solder paste.
[0064] refer to Fig.10 , Fig.10 It is a schematic diagram of a steel mesh opening selection method provided in an embodiment of the present application, including steps 101 to 103.
[0065] 101. Obtain a warpage degree of an integrated circuit module.
[0066] In actual application scenarios, the warpage of the integrated circuit module can be obtained by contact measuring instruments including but not limited to contour measuring instruments, micrometers, three-dimensional coordinate measuring instruments, or non-contact optical measurement methods. The specific acquisition method is not limited in this application.
[0067] 102. If the warpage is greater than or equal to the warpage threshold, use a target steel mesh, the target steel mesh including a steel mesh opening structure having a plurality of pin openings corresponding to a plurality of pin pads of the integrated circuit module and having lengths that are not completely the same.
[0068] The target steel mesh may include the steel mesh open hole structure in any of the above embodiments.
[0069] 103. If the warpage is less than the warpage threshold, a conventional steel mesh is used, wherein the conventional steel mesh includes a steel mesh opening structure having the same length as a plurality of pin openings corresponding to a plurality of pin pads of the integrated circuit module.
[0070] The warping threshold may be a value related to the quality inspection standard of the deformation of the integrated circuit module when it leaves the factory. For example, the warping threshold may be 0.5% of the quality inspection standard of the deformation of the integrated circuit module.
[0071] The above implementation method can more flexibly and accurately improve the welding strength of the side pin pads of integrated circuit modules with different warping degrees by judging the warping degree of the integrated circuit module and selecting and using a corresponding steel mesh opening structure accordingly.
[0072] Optionally, if the warping of the regions near the two sides of the same side of the integrated circuit module is greater than the warping of the region near the middle, that is, the integrated circuit module is warped upward, a method including Figure 5 The steel mesh with an open-pore structure provided by the technical solution in the steel mesh; if the warping degree of the areas near the two sides of the same side of the integrated circuit module is less than the warping degree of the area near the middle, that is, the integrated circuit module is warped downward, it is possible to use Figure 6 The technical solution provided in the present invention is a steel mesh with an open-pore structure.
[0073] In the above embodiment, according to the specific warping type of the integrated circuit module, such as upward warping or downward warping, a matching steel mesh opening structure, that is, a matching gradient distribution type of the steel mesh pin opening extension, is selected, which can more specifically improve the welding strength of the module side pin pad.
[0074] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A steel mesh open hole structure, characterized in that: include: A plurality of pin openings (41) corresponding to a plurality of pin pads (123) of an integrated circuit module (1); each pin opening (41) comprises a pin opening bottom portion (411) corresponding to a bottom pin pad (1211) of the integrated circuit module (1) and a pin opening extension portion (412) corresponding to a side pin pad (1221) of the integrated circuit module (1); the lengths (d1) of the pin opening extension portions (412) of the plurality of pin openings (41) are not completely the same.
2. The steel mesh open hole structure according to claim 1, characterized in that: The length (d1) of the pin opening extension portion (412) corresponding to the side pin pad (1221) on the same side of the integrated circuit module (1) is distributed in a gradient manner; The length (d1a) of the pin hole extension part (412) corresponding to the side pin pad (1221) located in the middle is smaller than the length (d1b) of the pin hole extension part (412) corresponding to the side pin pads (1221) located on both sides.
3. The steel mesh open hole structure according to claim 1, characterized in that: The lengths of the pin opening extension portions (412) corresponding to the side pin pads (1221) on the same side of the integrated circuit module (1) are distributed in a gradient manner; The length (d1a) of the pin hole extension part (412) corresponding to the side pin pad (1221) located in the middle is greater than the length (d1b) of the pin hole extension part (412) corresponding to the side pin pads (1221) located on both sides.
4. The steel mesh open hole structure according to any one of claims 1 to 3, characterized in that: The integrated circuit module (1) is arranged on a PCB, and the outward extension length (d2) of the pin opening (41) is greater than or equal to 0.85 mm and less than or equal to 1.00 mm; the outward extension length (d2) is the length of the portion of the pin opening (41) extending out of the corresponding PCB pin pad.
5. The steel mesh open hole structure according to any one of claims 1 to 3, characterized in that: There is a step portion (413) protruding from the surface of the steel mesh (4) around the pin opening (41), and the thickness (d6) of the pin opening (41) is 0.18 mm.
6. The steel mesh open hole structure according to any one of claims 1 to 3, characterized in that: The steel mesh opening structure further comprises a bottom opening (43) corresponding to the bottom pad of the integrated circuit module (1), and the area of the bottom opening (43) is 70%-80% of the area of the bottom pad of the PCB.
7. A method for selecting a steel mesh opening structure, characterized in that: include: Obtaining the warpage of the integrated circuit module; If the warping degree is greater than or equal to the warping threshold, using a steel mesh comprising a steel mesh open-pore structure as claimed in any one of claims 1 to 6; If the warping degree is less than the warping threshold, a conventional perforated steel mesh is used; in the conventional perforated steel mesh, the lengths of the multiple pin openings corresponding to the multiple pin pads of the integrated circuit module are the same.
8. The method according to claim 7, characterized in that If the warping of the areas near the two sides of the same side of the integrated circuit module is greater than the warping of the area near the middle, a steel mesh including the steel mesh open hole structure as claimed in claim 2 is used; If the warping of the areas near the two sides of the same side of the integrated circuit module is smaller than the warping of the area near the middle, a steel mesh including the steel mesh open hole structure as described in claim 3 is used.