A stencil structure, a squeegee structure, and a printing device

Abstract

This utility model relates to the field of circuit board printing equipment, and particularly to a stencil structure, a squeegee structure, and printing equipment. The stencil structure includes a stencil with a groove. The groove includes a printing area and a non-printing area, with the non-printing area located at both ends of the printing area. Multiple printing holes are arranged on the bottom surface of the printing area, and enlarged holes are provided around each printing hole, communicating with it. By providing enlarged holes around the printing holes and communicating with them, the solder paste coverage area is increased, allowing the solder paste to better cover the edges or corners of the chip. This reduces the possibility of molding compound entering the chip corners during subsequent compression molding, effectively improving the process stress of the chip product and enhancing product quality.

Description

Technical Field

[0001] This utility model relates to the field of circuit board printing equipment, and in particular to a stencil structure, a squeegee structure, and a printing equipment. Background Technology

[0002] With the rapid development of the semiconductor industry, solder paste and other solderable materials are often used to print lead frames and other components during circuit board printing. This printing process requires the use of a stencil, which is tightly attached to the workpiece. A squeegee is then used to evenly print the solder paste and other solderable materials onto the designated positions on the workpiece.

[0003] When solder paste or other solderable materials are used to print lead frames, the through holes on the stencil are generally positively correlated with the size of the workpiece (chip) during the soldering process, so as to achieve the purpose of the solderable material (solder paste) covering the contact surface between the workpiece and the workpiece.

[0004] Currently, the through-holes on conventional stencils are single circular or square. After the squeegee coating process, a single circular or square solder paste is formed on the chip. Because the solder paste tends to accumulate in narrow areas of the soldering contact during high-temperature sintering, it is easy for the edges / corners on the back of the chip (the surface in contact with the solder paste) to be without solder paste, which is called a void in the industry.

[0005] During the compression molding process, if the solder paste is not completely covered at the edges and corners of the chip, the molten molding compound can enter the voids at the chip's edges and corners. When the temperature changes in subsequent processes (such as reflow soldering), the state of the molding compound at the four corners changes (expansion, etc.), generating process stress. This makes the chip edges and corners prone to pressure damage, affecting product quality. Utility Model Content

[0006] The purpose of this utility model is to address the problem in the background art where conventional stencils have single circular or square through-holes. After the squeegee coating operation, a single circular or square solder paste is formed on the chip, which easily leads to the absence of solder paste at the edges or corners on the back of the chip, affecting product quality. This invention provides a stencil structure, a squeegee structure, and a printing equipment.

[0007] In a first aspect, the present invention provides a screen structure, including a screen, wherein the screen is provided with a groove, the groove includes a printing area and a non-printing area, the non-printing area is located at both ends of the printing area, the bottom surface of the printing area is provided with a plurality of printing holes, and the printing holes are provided with enlarged holes around the printing holes, the enlarged holes being connected to the printing holes.

[0008] By setting enlarged holes around the printed holes and connecting them, the solder paste coverage area is increased, so that the solder paste can better cover the edges or corners of the chip. This reduces the situation where molding compound enters the chip corners during the subsequent molding process, effectively improves the process stress of chip products, and enhances product quality.

[0009] Preferably, the printed hole is a rectangular hole, and the enlarged hole is located at the four right angles of the printed hole.

[0010] Preferably, the printed hole is a circular hole, and the enlarged holes are spaced apart around the printed hole in a circumferential direction.

[0011] Preferably, the printed holes are arranged in a matrix.

[0012] Preferably, the ratio of the enlarged hole size to the printed hole size is 0.25 to 0.45.

[0013] In a second aspect, the present invention provides a scraping structure, including a scraper part and a mesh plate structure as described in the present invention. The scraper part includes a fixing frame, and two scrapers arranged opposite to each other are installed on the lower part of the fixing frame. Each scraper has a scraping plate at its bottom. The upper part of the scraping plate is connected to the scraper, and the lower part of the scraping plate is inclined toward the other scraper. The lower part of the scraper is located inside the groove, and the scraper plate can slide along the bottom surface of the groove.

[0014] Preferably, the fixing frame has two downwardly extending side plates, which are arranged parallel to each other, and each side plate is detachably connected to a scraper.

[0015] Preferably, the end of the scraper away from the scraper plate is bolted to the side plate.

[0016] Preferably, the mounting bracket further has an upwardly extending mounting plate with a plurality of mounting holes.

[0017] In a third aspect, this utility model provides a printing device, including a workbench and the squeegee structure described in this utility model, wherein the screen is fixedly installed on the workbench; The workbench is also equipped with a movable platform, which is located above the mesh plate and is used to drive the fixed frame to move along the length of the slide groove.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. The stencil structure of this utility model increases the solder paste coverage area by setting enlarged holes around the printed holes and connecting them, so that the solder paste can better cover the edges or corners of the chip, thereby reducing the situation where molding compound enters the chip corners during the subsequent molding process, effectively improving the process stress of chip products and improving product quality.

[0019] 2. The squeegee structure of this utility model has two squeegees arranged opposite each other installed at the lower part of the fixed frame. Each squeegee has a squeegee plate at its bottom, the upper part of which is connected to the squeegee, and the lower part of the squeegee is located in the groove. The squeegee plate can slide along the bottom surface of the groove. By setting two squeegees, each with a squeegee plate at its bottom, when the squeegees reciprocate in the groove of the stencil, after the first squeegee plate scrapes the solder paste, there will be residual solder paste behind it. At this time, the second squeegee plate performs a secondary operation to scrape the residual solder paste, which is highly efficient and has a good solder paste scraping effect. Furthermore, the lower part of the squeegee plate is inclined towards the other squeegee, forming an inclined angle between the squeegee plate and the bottom surface of the groove. When the squeegee plate slides in the groove, it can exert a squeezing effect on the solder paste, pressing the solder paste into the printing hole better, thereby ensuring a good scraping effect during reciprocating motion and effectively avoiding the phenomenon of solder paste stringing on the soldered object.

[0020] 3. The printing equipment of this utility model installs the screen on the worktable to fix the screen. The movable table drives the fixed frame to move along the length of the slide groove, providing stable power for the bidirectional scraping of solder paste by the two squeegees, and achieving the effect of bidirectional smoothing of solder paste. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model.

[0022] Figure 2 This is a cross-sectional schematic diagram of the present invention.

[0023] Figure 3 This is a structural diagram of the mounting bracket and scraper.

[0024] Figure 4 This is a schematic diagram of the first preferred structure of the stencil.

[0025] Figure 5 yes Figure 4 A magnified view of part A.

[0026] Figure 6 This is a schematic diagram of the second preferred structure of the stencil.

[0027] Figure 7 yes Figure 6 A magnified view of part B.

[0028] Marked in the image: 1-Scraper, 2-Scrubber, 3-Screen plate, 4-Slide groove, 41 - Printing area, 42 - Non-printing area 5-Fixed bracket, 51-Side panel, 52-Mounting plate, 6-Printing holes, 7-Enlarged hole. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to specific embodiments. However, it should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0030] Unless otherwise specified, the use of terms such as "upper," "lower," "left," "right," "center," "inner," and "outer" to indicate orientation or positional relationships in the description of specific embodiments of this utility model is based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product / equipment / device is typically placed during use. These terms are merely for the purpose of facilitating the description of the utility model solution or simplifying the description in specific embodiments, enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on this utility model.

[0031] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are set as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," "parallel," or "coaxial" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the present invention.

[0032] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0033] Furthermore, in the description of the embodiments of this utility model, "several", "multiple", and "several" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0034] Furthermore, in the description of the technical solution of this utility model, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "equipped with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to common connection methods in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0035] Example 1 like Figures 4-7 As shown, this embodiment discloses a screen structure, including a screen 3. The screen 3 is provided with a groove 4. The groove 4 includes a printing area 41 and a non-printing area 42. The non-printing area 42 is located at both ends of the printing area 41. The bottom surface of the printing area 41 is provided with a plurality of printing holes 6. The printing holes 6 are surrounded by enlarged holes 7, which are connected to the printing holes 6.

[0036] In this embodiment, by setting enlarged holes 7 connected to the printed holes 6 around them, the solder paste coverage area is increased, so that the solder paste can better cover the edges or corners of the chip, thereby reducing the situation where molding compound enters the chip corners during the subsequent compression molding process, effectively improving the process stress of the chip product and improving product quality.

[0037] In this embodiment, the enlarged hole 7 is connected to the printed hole 6, which can effectively increase the area of ​​the solder paste, thereby increasing the contact area between the solder paste and the workpiece and improving the subsequent soldering effect.

[0038] The groove 4 includes a printing area 41 and a non-printing area 42. The non-printing area 42 is located at both ends of the printing area 41, providing a stopping and buffering space for the subsequent scraper part, avoiding collision when the scraper part slides to the edge of the screen 3, and ensuring the stability of the scraping process.

[0039] In one or more implementations, such as Figure 6 , Figure 7As shown, the printing hole 6 is a rectangular hole, and the enlarged hole 7 is located at the four right angles of the printing hole 6, and the enlarged hole 7 is connected to the printing hole 6.

[0040] In this embodiment, there are 4 enlarged holes 7, and the enlarged holes 7 are located at the four right angles of the printed holes 6. After the solder paste is applied, 4 small solder pastes are formed at the four corners of the rectangular solder paste, which can effectively increase the area of ​​the solder paste.

[0041] In one or more implementations, such as Figure 4 , Figure 5 As shown, the printing hole 6 is a circular hole, and the enlarged holes 7 are arranged at intervals around the printing hole 6 in the circumference, and the enlarged holes 7 are connected to the printing hole 6.

[0042] The enlarged holes 7 are spaced around the printed holes 6 in a circumferential manner. After the solder paste is applied, four small solder pastes are formed at the edge of the circular solder paste, which can effectively increase the area of ​​the solder paste.

[0043] In an optional implementation, the number of enlarged holes 7 is 4.

[0044] In optional implementations, such as Figure 4 As shown, the printing holes 6 are arranged in a matrix.

[0045] The printing holes 7 are arranged in a matrix, which matches the matrix distribution of welding points on the workpiece, enabling simultaneous printing at multiple points and improving printing efficiency.

[0046] In an optional embodiment, the ratio of the size of the enlarged hole 7 to the size of the printed hole 6 is 0.25 to 0.45.

[0047] The enlarged hole 7 increases the space around the printed hole 6, which is beneficial for the filling and release of solder paste in the printed hole 6 and improves the smoothness of solder paste filling. The size ratio is controlled between 0.25 and 0.45. This ensures the structural strength of the printed hole 6 while preventing the printed hole 6 from deforming or the solder paste from spreading excessively due to the enlarged hole 7 being too large. It also prevents the enlarged hole 7 from failing to improve the filling effect of the solder paste due to being too small, thereby ensuring printing accuracy and uniformity.

[0048] Example 2 like Figures 1-2 As shown, this embodiment discloses a scraping structure, including a scraper part and a mesh plate structure as described in Embodiment 1. The scraper part includes a fixing frame 5. Two scrapers 1 arranged opposite to each other are installed on the lower part of the fixing frame 5. Each scraper 1 has a scraping plate 2 at its bottom. The upper part of the scraping plate 2 is connected to the scraper 1, and the lower part of the scraping plate 2 is inclined towards the other scraper 1. The lower part of the scraper 1 is located inside the groove 4, and the scraper plate 2 can slide along the bottom surface of the groove 4.

[0049] In this embodiment, two oppositely arranged scrapers 1 are installed at the lower part of the fixing frame 5. Each scraper 1 has a scraper plate 2 at its bottom. The upper part of the scraper plate 2 is connected to the scraper 1, and the lower part of the scraper 1 is located in the slide groove 4. The scraper plate 2 can slide along the bottom surface of the slide groove 4. By setting two scrapers 1, each with a scraper plate 2 at its bottom, when the scraper 1 moves back and forth in the slide groove 4 of the stencil 3, after the first scraper plate 2 scrapes the solder paste, there will be residual solder paste behind the first scraper plate 2. At this time, the second scraper plate 2 performs a secondary operation to scrape the residual solder paste, which is highly efficient and has a good solder paste scraping effect. Furthermore, the lower part of the squeegee 2 is inclined toward another squeegee 1, and the squeegee 2 and the bottom surface of the slide 4 form an inclined angle. When the squeegee 2 slides in the slide 4, it can exert a squeezing effect on the solder paste, and press the solder paste into the printing hole 6 better, thereby ensuring good squeegee effect during reciprocating motion and effectively avoiding the phenomenon of solder paste stringing on the soldered object. Furthermore, the scraper 2 can slide along the bottom surface of the groove 4 to ensure that the scraper 2 can adhere to the groove 4, so as to achieve a better scraping effect.

[0050] In one or more implementations, such as Figure 3 As shown, the mounting bracket 5 has two downwardly extending side plates 51, which are arranged parallel to each other, and a scraper 1 is detachably connected to each side plate 51.

[0051] Two parallel side plates 51 provide a stable mounting reference for the two scrapers 1, ensuring that the two scrapers 1 can maintain a relative positional relationship, avoiding uneven solder paste scraping caused by the offset of the scrapers 1 during scraping, and further improving the accuracy of solder paste leveling. Meanwhile, the scraper 1 is detachably connected to the side plate 51, which makes it easy to replace scrapers 1 of different specifications according to the requirements of solder paste type, stencil 3 thickness, etc., thereby reducing equipment maintenance costs and improving structural adaptability.

[0052] In an optional embodiment, the end of the scraper 1 furthest from the scraper plate 2 is bolted to the side plate 51. When the scraper 1 needs to be replaced, it can be disassembled simply by loosening the bolt, which is simple and efficient.

[0053] In optional implementations, such as Figure 3 As shown, the mounting bracket 5 also has an upwardly extending mounting plate 52, which has multiple mounting holes.

[0054] The mounting plate 52 extends upward on the fixed frame 5. The mounting plate 52 has multiple mounting holes so that the fixed frame 5 can be installed on a movable external device through the mounting plate 52, thereby driving the fixed frame 5 to move and controlling the reciprocating motion of the scraper 1.

[0055] Example 3 Based on Example 2, such as Figure 1 , Figure 2 As shown, this embodiment discloses a printing device, including a worktable and a squeegee structure as described in Embodiment 2, with the screen 3 fixedly installed on the worktable; The workbench is also equipped with a movable table, which is located above the mesh plate 3 and is used to drive the fixed frame 5 to move along the length of the slide 4.

[0056] The stencil 3 is installed on the workbench to fix the stencil 3. The movable table drives the fixed frame 5 to move along the length of the slide 4, providing stable power for the two scrapers 1 to scrape the solder paste in both directions, so as to achieve the effect of scraping the solder paste in both directions. Furthermore, the fixed frame 5 is connected to the movable table, and the movable table drives the fixed frame 5 to reciprocate to achieve bidirectional scraping of the two scrapers 1; Specifically, the mounting plate 52 of the fixed frame 5 is bolted to the movable platform to achieve the connection between the fixed frame 5 and the movable platform.

[0057] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A mesh panel structure, characterized in that, Includes a screen plate (3), on which a groove (4) is provided. The groove (4) includes a printing area (41) and a non-printing area (42). The non-printing area (42) is located at both ends of the printing area (41). The bottom surface of the printing area (41) is provided with a plurality of printing holes (6). The printing holes (6) are surrounded by enlarged holes (7), which are connected to the printing holes (6).

2. The mesh structure according to claim 1, characterized in that, The printing hole (6) is a rectangular hole, and the enlarged hole (7) is located at the four right angles of the printing hole (6).

3. The mesh structure according to claim 1, characterized in that, The printing hole (6) is a circular hole, and the enlarged holes (7) are arranged circumferentially around the printing hole (6).

4. The mesh structure according to claim 1, characterized in that, The printed holes (6) are arranged in a matrix.

5. A mesh panel structure according to claim 1, characterized in that, The ratio of the size of the enlarged hole (7) to the size of the printed hole (6) is 0.25 to 0.

45.

6. A coating structure, characterized in that, The device includes a scraper section and a mesh structure as described in any one of claims 1-5. The scraper section includes a fixing frame (5). Two scrapers (1) arranged opposite to each other are installed on the lower part of the fixing frame (5). Each scraper (1) has a scraper plate (2) at its bottom. The upper part of the scraper plate (2) is connected to the scraper (1), and the lower part of the scraper plate (2) is inclined toward the other scraper (1). The lower part of the scraper (1) is located in the groove (4), and the scraper plate (2) can slide along the bottom surface of the groove (4).

7. The adhesive scraping structure according to claim 6, characterized in that, The mounting bracket (5) has two downwardly extending side plates (51) arranged parallel to each other, and a scraper (1) is detachably connected to each side plate (51).

8. The adhesive scraping structure according to claim 7, characterized in that, The end of the scraper (1) away from the scraper plate (2) is attached to the side plate (51).

9. The adhesive scraping structure according to claim 7, characterized in that, The mounting bracket (5) also has an upwardly extending mounting plate (52) with a plurality of mounting holes.

10. A printing apparatus, characterized in that, Includes a workbench and a scraping structure as described in any one of claims 6-9, wherein the mesh plate (3) is fixedly mounted on the workbench; The workbench is also provided with a movable platform, which is located above the mesh plate (3) and is used to drive the fixed frame (5) to move along the length direction of the slide groove (4).

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