Solder paste printing screen

Abstract

The application provides a tin paste printing screen, which is used for printing tin paste on a circuit board, the circuit board is provided with a packaging chip printing area and a component mounting area, the packaging chip printing area is arranged at intervals from the component mounting area, and the tin paste printing screen comprises a screen body, a avoiding groove is arranged on one side of the screen body, the avoiding groove is arranged in correspondence with the packaging chip printing area, and a plurality of screen holes corresponding to the component mounting area are arranged on the screen body. The tin paste printing screen provided by the application solves the technical problem of continuous tin caused by the fact that the doctor blade pushes the tin paste to roll on the steel screen.

Description

Technical Field

[0001] This application belongs to the field of electronic manufacturing technology, and more specifically, relates to a solder paste printing stencil. Background Technology

[0002] Flip chips are manufactured using solder paste printing. Because the pads of flip chips are very small, a precision electroformed stencil is typically used for solder paste printing. However, this specialized stencil can only cover the flip chip area and cannot simultaneously meet the printing needs of the component placement area. In actual production, the solder paste for the flip chip area must be printed first using a specialized stencil, and then a regular stencil is used for the component placement area. When the squeegee pushes the solder paste across the regular stencil, the solder paste may roll into the already printed flip chip area, coming into contact with the printed solder paste, thus causing solder bridging. Utility Model Content

[0003] The purpose of this application is to provide a solder paste printing stencil to solve the technical problem in the prior art where a squeegee pushes the solder paste to roll on the stencil, causing solder bridging.

[0004] To achieve the above objectives, the technical solution adopted in this application is as follows: a solder paste printing stencil is provided, which is used to print solder paste on a circuit board. The circuit board is provided with a chip packaging area and a component mounting area, which are spaced apart. The solder paste printing stencil includes a stencil body, and an avoidance groove is provided on one side of the stencil body, which is corresponding to the chip packaging area. The stencil body is provided with a plurality of mesh holes corresponding to the component mounting area.

[0005] In an optional embodiment, the solder paste printing stencil further includes a thickening layer disposed on the side of the stencil body opposite to the clearance groove and corresponding to the clearance groove.

[0006] In one alternative embodiment, the thickness of the thickening layer is 0.02 mm to 0.06 mm.

[0007] In one alternative embodiment, the thickness of the thickening layer is 0.04 mm.

[0008] In one alternative embodiment, the mesh is provided on at least one side of the clearance groove.

[0009] In one alternative embodiment, the thickness of the mesh body is 0.08 mm to 0.12 mm.

[0010] In one alternative embodiment, the thickness of the mesh body is 0.08 mm.

[0011] In one alternative embodiment, the depth of the clearance groove is 0.06 mm to 0.07 mm.

[0012] In one alternative embodiment, the shape of the clearance groove matches the shape of the printed area of ​​the packaged chip.

[0013] In an alternative embodiment, the PCB body further includes positioning holes for engaging with positioning structures on the PCB.

[0014] The beneficial effects of the solder paste printing stencil provided in this application are as follows: Compared with the prior art, the solder paste printing stencil of this application provides a relief groove on the stencil body. When in use, the relief groove corresponds to the chip packaging printing area, which can effectively prevent solder paste from entering the chip packaging printing area, avoid mixing and connection of solder paste in different areas, and solve the problem of solder bridging. At the same time, the relief groove can effectively protect the solder paste from damage. Since improper connection of solder paste is avoided, the quality and reliability of circuit board production can be improved, and the need for rework and repair can be reduced. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A front view of the solder paste printing stencil provided in the embodiments of this application. Figure 1 ;

[0017] Figure 2 A front view of the solder paste printing stencil provided in the embodiments of this application. Figure 2 ;

[0018] Figure 3 This is a partial cross-sectional view of the solder paste printing stencil and circuit board provided in an embodiment of this application.

[0019] The following are the labeling elements in the figure:

[0020] 100-Solder paste printing stencil; 10-Stencil body; 11-Grease groove; 12-Mesh opening; 20-Thickening layer; 200-Circuit board; 210-Package chip printing area; 220-Component mounting area; 300-Solder paste. Detailed Implementation

[0021] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0022] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0023] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0025] Flip chips are manufactured using solder paste printing. Because the pads of flip chips are very small, precision electroformed stencils are typically used for solder paste printing. However, these specialized stencils can only cover the flip chip area and cannot simultaneously meet the printing needs of component mounting areas (such as conventional chip pads). In actual production, a specialized stencil is first used to print solder paste for the flip chip area, and then a conventional stencil is used for printing conventional chip pads and ball grid array packages. When the squeegee pushes the solder paste across the conventional stencil, the pressure applied by the squeegee causes the solder paste to continuously roll on the stencil surface. The solder paste rolling path may cover the edges of the already printed area. Under mechanical stress, the liquid metal paste breaks through the area boundary and rolls into the already printed flip chip area, coming into contact with the printed solder paste, thus causing solder bridging. This solder bridging defect directly causes an electrical short circuit on the circuit board, directly affecting the electrical performance and reliability of the product, and in severe cases, even leading to product scrap. Solder paste bridging significantly reduces product yield, and cross-regional solder bridging defects require rework repair, increasing production costs and extending production cycles. Furthermore, using conventional stencils can lead to solder joint deformation or collapse, damaging the solder paste corresponding to the flip chip solder balls and affecting soldering quality.

[0026] Please refer to the following: Figures 1 to 3The solder paste printing stencil 100 provided in this application embodiment will now be described. The solder paste printing stencil 100 is used to print solder paste on a circuit board 200. The circuit board 200 is provided with a chip packaging area 210 and a component mounting area 220. The chip packaging area 210 and the component mounting area 220 are spaced apart. The solder paste printing stencil 100 includes a stencil body 10. An avoidance groove 11 is provided on one side of the stencil body 10. The avoidance groove 11 is correspondingly provided with the chip packaging area 210. The stencil body 10 has a plurality of mesh holes 12 corresponding to the component mounting area 220.

[0027] The solder paste printing stencil 100 can be a laser-cut stencil, an electroformed stencil, or a stepped stencil, etc. The circuit board 200 is provided with a chip packaging printing area 210 and a component mounting area 220. The chip packaging printing area 210 requires a precision electroformed stencil for solder paste printing, while the component mounting area 220 uses the solder paste printing stencil 100 for solder paste printing.

[0028] The clearance groove 11 refers to a recessed structure opened on one side of the PCB body 10. Specifically, it can be implemented by laser cutting or chemical etching process. The clearance groove 11 is set corresponding to the packaged chip printing area 210. It is used to avoid the packaged chip printing area 210 during the printing process to prevent the solder paste from being pushed to this area by the squeegee and causing solder bridging. At the same time, it can protect the solder paste from damage.

[0029] The mesh 12 refers to the through-hole structure formed on the surface of the PCB body 10, and the mesh 12 is correspondingly set in the component mounting area 220. The mesh 12 can be realized by mechanical stamping or laser drilling process. The mesh 12 is used to allow solder paste to pass through and adhere to the corresponding pad area of ​​the PCB 200 during printing, ensuring that solder paste printing is completed normally in areas other than the package chip printing area 210.

[0030] By simultaneously providing clearance grooves 11 and mesh openings 12 on the PCB body 10, the clearance grooves 11 form a recessed area corresponding to the chip packaging printing area 210, which can avoid interference to this area during solder paste printing. The clearance grooves 11 directly avoid the chip packaging printing area 210, preventing the squeegee from contacting the printed area when pushing the solder paste. The multiple mesh openings 12 ensure that the solder paste printing of the component mounting area 220 is completed in one go, thereby solving the problem of solder bridging caused by secondary printing.

[0031] When the stencil body 10 is placed on the circuit board 200, the clearance groove 11 is aligned with the chip packaging printing area 210. During printing, the squeegee pushes the solder paste across the surface of the stencil body 10, and the solder paste is printed onto the component mounting area 220 of the circuit board 200 through the mesh openings 12. The clearance groove 11, being recessed, does not come into contact with the solder paste, thus protecting the chip packaging printing area 210. This design fulfills the solder paste printing requirements of the component mounting area 220 during the printing process and avoids solder bridging problems that may occur with step-by-step printing.

[0032] The chip packaging printing area 210 and the component mounting area 220 are spaced apart, that is, the clearance groove 11 and the mesh 12 are spaced apart, so that there is a solid structure between the clearance groove 11 and the mesh 12, surrounding the edge of the clearance groove 11. When the squeegee pushes the solder paste to move in the component mounting area 220, the boundary of the solid structure blocks the solder paste from flowing towards the clearance groove 11, effectively preventing the solder paste from rolling into the clearance groove 11 area during the printing process, thereby avoiding contact between the solder paste and the already printed solder paste and reducing the occurrence of solder bridging problems.

[0033] The clearance groove 11 forms a physical barrier, preventing solder paste from entering the chip packaging printing area 210, effectively preventing the mixing and connection of solder paste from different areas. At the same time, the clearance groove 11 does not affect the printing function of other areas of the stencil body 10, ensuring the overall printing effect.

[0034] The material of the mesh body 10 can be stainless steel or nickel alloy, etc. In some embodiments, the mesh body 10 is in the shape of a rectangular sheet.

[0035] In other embodiments, the clearance groove 11 is a rectangular recess, and the shape and size of the clearance groove 11 match the printed area 210 of the packaged chip on the circuit board 200. The clearance groove 11 is formed on the surface of the PCB body 10 by a laser etching process.

[0036] The plate mesh body 10 has multiple mesh holes 12 in the area outside the clearance groove 11. The mesh holes 12 can be rectangular or circular, etc.

[0037] In use, the stencil body 10 is placed on the circuit board 200 to be printed, ensuring that the clearance groove 11 is precisely aligned with the package chip printing area 210 on the circuit board 200. Then, solder paste is applied to the stencil body 10, and a squeegee is used to push the solder paste through the mesh 12 onto the circuit board 200. Figure 3 Due to the presence of the clearance groove 11, external solder paste 300 will not enter the package chip printing area 210 and will not affect the solder paste 300 of the package chip printing area 210, thereby achieving protection of the solder paste 300 in this area.

[0038] Compared with the prior art, the solder paste printing stencil 100 provided in this application embodiment has a relief groove 11 on the stencil body 10. When in use, the relief groove 11 corresponds to the packaged chip printing area 210, which can effectively prevent solder paste from entering the packaged chip printing area 210, avoid the mixing and connection of solder paste in different areas, and solve the problem of solder bridging. At the same time, the relief groove 11 can protect the solder paste from damage. Since improper connection of solder paste is avoided, the quality and reliability of the circuit board 200 production can be improved, and the need for rework and repair can be reduced.

[0039] Please refer to some embodiments of this application. Figure 1 The solder paste printing stencil 100 also includes a thickening layer 20, which is disposed on the side of the stencil body 10 away from the relief groove 11 and is correspondingly disposed to the relief groove 11.

[0040] By setting a thickening layer 20, the thickening layer 20 is placed on the side of the PCB body 10 away from the relief groove 11, and the area covered by the thickening layer 20 coincides with the projected position of the relief groove 11. The thickening layer 20 can be integrated with the PCB body 10 into a whole structure through welding or electroforming processes, forming a stepped thickening structure in the thickness direction of the PCB body 10. The superimposed thickness of the PCB body 10 and the thickening layer 20 increases the bending stiffness of this area and effectively suppresses the elastic deformation of the PCB body 10 under squeegee pressure; when the squeegee applies pressure to the PCB body 10 for solder paste printing, the thickening layer 20 forms a local reinforcement structure in the corresponding area of ​​the relief groove 11.

[0041] During the component placement process in the printed circuit board (PCB) mounting area 220, the flatness of the clearance groove 11 area is maintained to prevent the lower surface of the PCB body 10 from contacting the printed flip chip solder paste. The thickening layer 20 can be made of stainless steel and processed by laser cutting or electroforming. The thickening layer 20 can also be made of the same material as the PCB body 10. The thickening layer 20 can be connected to the PCB body 10 by soldering, bonding, or mechanical fixing.

[0042] The shape and size of the thickening layer 20 are matched with the clearance groove 11 to ensure that the thickening layer 20 can accurately cover the clearance groove 11 area. In addition, the thickening layer 20 also improves the strength and stability of the mesh body 10 in the clearance groove 11 area and extends the service life of the mesh body 10.

[0043] In some embodiments of this application, the thickness of the thickening layer 20 is 0.02 mm to 0.06 mm.

[0044] The English abbreviation mm used in this application corresponds to the Chinese word millimeter.

[0045] The thickness of the thickening layer 20 is limited to 0.02mm to 0.06mm, so that the total thickness of the stencil body 10 in the clearance groove 11 area is close to or greater than the original thickness of the stencil body 10. This ensures structural strength while preventing abrupt changes in the overall stiffness of the stencil body 10 due to excessive thickness of the thickening layer 20, which could affect the printing pressure distribution. Specifically, the thickness range of the thickening layer 20 is limited by a lower limit of 0.02mm to ensure effective support for the stencil body 10 in the clearance groove 11 area, preventing a decrease in local strength of the stencil body 10 due to the presence of the clearance groove 11; and by an upper limit of 0.06mm, uneven pressure distribution during squeegee printing is prevented due to excessive thickness of the thickening layer 20.

[0046] In some embodiments of this application, the thickness of the thickening layer 20 is 0.04 mm. By setting the 0.04 mm thickening layer 20, effective compensation is achieved for the area of ​​the clearance groove 11, ensuring the uniformity of the overall thickness of the stencil body 10. Through the composite structure of the thickening layer 20 and the stencil body 10, targeted reinforcement of the clearance groove 11 area is achieved while maintaining the original printing function of the mesh 12. Furthermore, the thickness range of the thickening layer 20 can be coordinated with the thickness of the stencil body 10 and the depth of the clearance groove 11.

[0047] By providing a thickening layer 20 on the side of the PCB body 10 away from the clearance groove 11, the thickness of the clearance groove 11 area is effectively increased. Thus, during solder paste printing, the thickening layer 20 can prevent the solder paste pushed by the squeegee from rolling into the clearance groove 11 area, avoiding contact between the solder paste and the printed package chip area, thereby effectively solving the solder bridging problem.

[0048] Please refer to some embodiments of this application. Figure 1 and Figure 2 The mesh 12 is provided on at least one side of the clearance groove 11.

[0049] Multiple mesh openings 12 for solder paste printing are provided on one or both sides (or around) of the clearance groove 11. These mesh openings 12 correspond to the component mounting area 220 (such as conventional chip components, ball grid array packages, etc.) of the circuit board 200. Figure 2 Multiple mesh openings 12 are arranged on three sides of the clearance groove 11.

[0050] By rationally arranging the positions of the clearance slots 11 and the mesh holes 12, the space of the board body 10 can be utilized more efficiently; the mesh holes 12 are distributed around the clearance slots 11, which not only meets the requirements of solder paste amount in different areas, but also ensures the overall structural strength.

[0051] In some embodiments, please refer to Figure 1Multiple clearance slots 11 are provided, spaced apart on the PCB body 10. When there are multiple packaged chip printing areas 210 on the circuit board 200, multiple clearance slots 11 can be provided accordingly. The multiple clearance slots 11 are distributed at intervals on the PCB body 10, and each clearance slot 11 corresponds one-to-one with a different packaged chip printing area 210 on the circuit board 200. The shape and size of the multiple clearance slots 11 are adjusted according to the actual layout of the corresponding packaged chip printing areas 210 to cover all areas that need to be cleared. The spacing between the clearance slots 11 can be adjusted according to actual needs, such as being evenly distributed or arranged according to the distribution of packaged chips on the circuit board 200. By providing multiple clearance slots 11, multiple packaged chip printing areas 210 can be protected simultaneously in one printing process. The provision of multiple clearance slots 11 allows the PCB body 10 to better adapt to circuit boards 200 with different layouts, increasing the versatility and applicability of the PCB body 10.

[0052] In some embodiments of this application, the thickness of the mesh body 10 is 0.08 mm to 0.12 mm.

[0053] The PCB body 10 balances structural strength and solder paste printing accuracy by limiting its thickness range. The PCB body 10 is generally made of metal sheet (such as stainless steel), and the thickness parameter directly affects its resistance to deformation and the size control of the mesh openings 12.

[0054] When the thickness of the stencil body 10 is set to between 0.08 mm and 0.12 mm, its rigidity is sufficient to resist the pressure of the squeegee on the surface of the stencil body 10, preventing solder paste from seeping into the clearance groove 11 area due to the collapse of the stencil body 10. For example, when the thickness of the stencil body 10 is 0.10 mm, its bending strength can withstand the squeegee pressure of conventional printing processes, while the dimensional accuracy of the mesh openings 12 can meet the requirements for solder paste transfer. By controlling the thickness of the stencil body 10 within this range, the structural stability between the clearance groove 11 and the mesh openings 12 is ensured, preventing the solder paste from contacting the already printed solder paste in adjacent areas due to the deformation of the stencil body 10 during the rolling process, thereby eliminating the problem of solder bridging.

[0055] In some embodiments of this application, the thickness of the stencil body 10 is 0.08 mm. This ensures both strength and the accuracy and uniformity of solder paste printing.

[0056] Furthermore, the thickness range of the stencil body 10 can be matched with the depth range of the clearance groove 11, enabling the stencil body 10 to effectively support solder paste rolling during printing while precisely controlling the amount of solder paste deposited through the mesh openings 12. In addition, a suitable thickness can also increase the service life of the stencil body 10, reduce replacement frequency, and thus lower production costs.

[0057] In some embodiments of this application, the depth of the clearance groove 11 is 0.06 mm to 0.07 mm.

[0058] The depth of the clearance groove 11 is limited to 0.06 mm to 0.07 mm, a range determined based on the balance between the thickness of the PCB body 10 and the clearance function. This ensures both the structural strength of the groove and effective clearance of the packaged chip printing area 210. By controlling the lower limit of the groove depth to be no less than 0.06 mm, the solder paste in the flip chip area can be prevented from collapsing due to insufficient groove depth; while the upper limit to be no more than 0.07 mm prevents excessive groove depth from weakening the mechanical stability of the PCB body 10.

[0059] When the squeegee pushes the solder paste with a set pressure, the 0.06mm to 0.07mm deep clearance groove 11 forms a precise physical isolation space, ensuring a safe distance between the rolling solder paste in the component mounting area 220 and the printed flip chip area.

[0060] In some embodiments, a clearance groove 11 with a depth of 0.06 mm is used, and the PCB body 10 retains an unetched area thickness of 0.04 mm, which not only meets the printing requirements of the component mounting area 220, but also blocks the lateral flow of solder paste through the vertical drop formed by the groove depth.

[0061] The depth of the clearance groove 11 is set within the range of 0.06mm to 0.07mm. While ensuring the structural strength of the PCB body 10, it effectively avoids the packaged chip printing area 210, preventing the squeegee from contacting the existing solder paste on the packaged chip printing area 210 during solder paste printing, thereby avoiding solder bridging. At the same time, this depth range will not excessively weaken the strength of the PCB body 10, ensuring the stability and durability of the PCB body 10 during use.

[0062] Please refer to some embodiments of this application. Figures 1 to 3 The shape of the clearance groove 11 matches the shape of the printed area 210 of the packaged chip.

[0063] The shape of the clearance groove 11 is matched with the shape of the packaged chip printing area 210. That is, the outline of the clearance groove 11 is cut according to the actual shape of the packaged chip printing area 210. For example, when the printing area is rectangular, the clearance groove 11 is also cut into a rectangle, and when the printing area is circular, the clearance groove 11 is cut into a circle. This effectively blocks the lateral migration path of solder paste during the printing process of the component mounting area 220. Since the edge of the clearance groove 11 completely matches the outline of the packaged chip printing area 210, no gap channel is generated between the stencil body 10 and the circuit board 200 when the squeegee applies pressure, thereby completely eliminating the physical conditions for solder paste to seep into the printed area during the rolling process.

[0064] In some embodiments of this application, the board body 10 further includes positioning holes (not shown in the figure) for engaging with positioning structures (not shown in the figure) on the circuit board 200.

[0065] The positioning structure on the circuit board 200 can be a positioning pin or a protrusion. By providing positioning holes to engage with the positioning structure on the circuit board 200, the clearance groove 11 of the stencil body 10 is ensured to align with the chip printing area 210 when the stencil body 10 is mounted onto the circuit board 200. During printing, the stencil body 10 is rigidly fixed to the circuit board 200 through the positioning holes, which also prevents lateral displacement caused by the squeegee pushing the solder paste. As a result, the solder paste in the component mounting area 220 is precisely confined within the mesh openings 12, and will not come into contact with the solder paste in the clearance groove 11 due to the offset of the stencil body 10, thereby eliminating the risk of solder bridging.

[0066] The positioning holes can be circular or rectangular in shape; there can be multiple positioning holes, distributed at the four corners of the board body 10; the positioning holes and the positioning structure of the circuit board 200 can be connected by plugging or snapping, for example, by inserting pins into the positioning holes to achieve fixation.

[0067] In some embodiments, four tapered positioning holes are symmetrically distributed around the perimeter of the mesh body 10, with the larger end of each hole facing outwards. The tapered positioning holes and positioning pins on the edge of the circuit board 200 form a clearance fit, and the taper of the positioning pins matches the taper of the positioning holes. When the mesh body 10 covers the surface of the circuit board 200, the tips of the positioning pins are embedded in the positioning holes, thus constraining the position between the mesh body 10 and the circuit board 200.

[0068] By setting positioning holes, precise positioning and engagement between the stencil body 10 and the circuit board 200 are achieved, effectively controlling the offset of the solder paste printing area. During the process of the squeegee pushing the solder paste to roll, the stencil body 10 and the circuit board 200 maintain a stable relative position, preventing solder paste from seeping into adjacent printing areas due to the displacement of the stencil body 10, thereby eliminating the risk of solder paste contact between different printing processes.

[0069] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A solder paste printing stencil, wherein the solder paste printing stencil is used to print solder paste on a circuit board, the circuit board having a chip packaging area and a component mounting area, the chip packaging area and the component mounting area being spaced apart, characterized in that, The device includes a PCB body, and a clearance groove is provided on one side of the PCB body, which is correspondingly provided with the printing area of ​​the packaged chip. The PCB body has multiple mesh holes corresponding to the component mounting area.

2. The stencil of claim 1, wherein, The solder paste printing stencil also includes a thickening layer, which is disposed on the side of the stencil body opposite to the clearance groove and is correspondingly disposed to the clearance groove.

3. The stencil of claim 2, wherein, The thickness of the thickening layer is 0.02 mm to 0.06 mm.

4. The stencil of claim 3, wherein, The thickness of the thickening layer is 0.04 mm.

5. The stencil of any one of claims 1 to 4, wherein, The mesh is located on at least one side of the clearance groove.

6. The solder paste printing stencil as described in any one of claims 1 to 4, characterized in that, The thickness of the mesh body is 0.08mm to 0.12mm.

7. The solder paste printing stencil as described in claim 5, characterized in that, The thickness of the mesh body is 0.08 mm.

8. The stencil of any one of claims 1 to 4, wherein, The depth of the clearance groove is 0.06mm to 0.07mm.

9. The stencil of any one of claims 1 to 4, wherein, The shape of the clearance groove matches the shape of the printed area of ​​the packaged chip.

10. The stencil of any one of claims 1 to 4, wherein, The board body also includes positioning holes, which are used to cooperate with positioning structures on the circuit board.

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