Lead frame structure capable of reducing knife loss during single cutting
By forming a thinner sliding cutter groove and necessary protruding grooves and hollow areas at the edge of the wire frame, the problem of excessive tool contact in the wire frame frame frame frame frame frame frame is solved, and the effect of reducing tool loss and extending tool life is achieved.
Patent Information
- Application Number
- CN202420042528.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-08
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2034-01-08
AI Technical Summary
In semiconductor packaging technology, the thickness of the frame area of the wire frame is the thickest when cutting, resulting in excessive contact between the tool and the metal, resulting in high tool loss, shortened service life, and increased tool cutting cost.
Design the wire frame to form multiple slide grooves at the edge, the thickness of the slide groove is smaller than the thickness of the wire frame, and is located in the cutting line area path, reducing the contact area between the tool and the metal, and adding protruding grooves and hollow areas where necessary to reduce tool contact. Improve cutting accuracy.
Effectively reduce tool loss during cutting order, extend tool service life, improve cutting quality and positioning accuracy, and reduce tool cutting costs.
Smart Images
Figure CN222146210U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of a wire frame, in particular to a wire frame structure which can reduce the knife loss during singulation. Background Art
[0002] In the semiconductor packaging process, in order to reduce costs and increase mass production, batch production and packaging are currently adopted, and the completed packaging structure is then cut into individual semiconductor components. This packaging manufacturing method first uses a metal lead frame, on which a plurality of package pre-setting areas for forming semiconductor packaging units are pre-defined, and then after the die bonding, wire bonding and encapsulation steps, singulation is performed along the cutting lines on the lead frame; the singulation cutting lines are defined between adjacent package pre-setting areas, so after the singulation step is completed, a plurality of semiconductor components can be obtained.
[0003] However, the multiple package pre-set areas of the lead frame are generally distributed in a matrix shape in the inner area, and the outer area is the lead frame frame area. When cutting, the tool cuts from the frame area to the package pre-set area. The frame area has no circuits and is the thickest area of the lead frame. Therefore, when cutting, the tool has more contact with the metal, which can easily cause excessive tool wear and reduce the service life, and also increase the cost of the cutter. Therefore, how to develop a lead frame structure to reduce tool wear and extend the service life of the tool is an urgent issue to be solved in this related field. Utility Model Content
[0004] The main purpose of the utility model is to provide a wire rack structure that reduces knife wear during singulation. The main purpose is to form a plurality of knife grooves near the edge of the wire rack, and each knife groove corresponds to a cutting path of a cutting line area, thereby reducing the cutting depth of the wire rack, thereby reducing the contact between the knife and the metal during cutting, and achieving the purpose of reducing knife wear during singulation.
[0005] In order to achieve the above-mentioned purpose, the utility model adopts the following technical solutions:
[0006] The utility model discloses a wire rack structure for reducing knife loss during singulation, comprising: a wire rack; a plurality of package unit pre-setting areas, which are arranged in a matrix and distributed on the wire rack; a plurality of cutting line areas, which are defined in the areas to be cut around the package unit pre-setting areas in the wire rack; a plurality of sliding knife grooves, which are formed at the edges adjacent to the wire rack and are all located in the paths corresponding to the cutting line areas, and the groove thickness of the sliding knife groove is less than the thickness of the wire rack.
[0007] As one of the preferred embodiments, the lead frame has a first surface and a second surface that are opposite to each other, and the cutting is performed from the direction of the second surface. The lead frame is subjected to a half-etching process on the second surface to form the knife groove.
[0008] As one of the preferred embodiments, the lead frame is formed with at least one protruding groove, the protruding groove is connected to the slide groove and is located away from the packaging unit pre-placement area, and the groove width of the protruding groove is smaller than the groove width of the slide groove.
[0009] As one of the preferred embodiments, the thickness of the protruding groove is the same as or different from the groove thickness of the sliding knife groove, and the groove thickness of the protruding groove is also smaller than the thickness of the lead frame.
[0010] As one of the preferred embodiments, the protruding groove is at a distance from the edge of the lead frame.
[0011] As one of the preferred embodiments, the lead frame is formed with a plurality of hollow areas, the slide knife groove has at least one hollow area, the hollow area is located in a local section of the slide knife groove, and the hollow area is a hole that penetrates the lead frame.
[0012] As one of the preferred embodiments, the lead frame has a plurality of first identification marks, each of which is used for identifying and locating the corresponding cutting line area, and the hollow area serves as a second identification mark, and the shape of the second identification mark is different from that of the first identification mark.
[0013] As one of the preferred embodiments, the hollow area is located at the junction of the sliding knife groove and the protruding groove.
[0014] As one of the preferred embodiments, the hollow area is a cross-shaped hole, an arrow-shaped hole or an elliptical hole.
[0015] As one of the preferred embodiments, the slide knife groove has a plurality of hollow areas, and when the plurality of hollow areas are used as identification marks, the shapes of the plurality of identification marks are different from the shape of the first identification mark.
[0016] As one of the preferred embodiments, the lead frame also includes a plurality of connecting pieces, which are located at the four corners of the packaging unit pre-set area and at the intersection of the two cutting line areas. The connecting pieces have a plurality of penetrating reinforcement holes. During the packaging operation, the plastic encapsulation colloid used will also fill the reinforcement holes.
[0017] As one of the preferred embodiments, the multiple cutting line areas include multiple first cutting line areas and multiple second cutting line areas, the first cutting line areas and the second cutting line areas are perpendicular to each other, and the multiple sliding knife grooves include a first sliding knife groove and a second sliding knife groove, the first sliding knife groove is located in the cutting path of the first cutting line area, and the second sliding knife groove is located in the cutting path of the second cutting line area.
[0018] Compared with the prior art, the wire rack structure of the utility model that reduces the knife wear during cutting has a thinner sliding knife groove. Due to the reduced thickness, the knife wear during cutting can be effectively reduced, or in the second cutting operation, the chance of the knife contacting the metal during the first cutting can be reduced, thereby reducing the knife wear. In addition, the protruding groove and multiple hollow areas can reduce the knife wear of the second cutting, thereby extending the service life of the knife. Moreover, by using at least one hollow area as an additional identification mark, the positioning accuracy of the cutting position of the knife can be improved, thereby improving the cutting quality. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a schematic diagram of the lead frame of the utility model.
[0020] Figure 2 It is an enlarged three-dimensional view of a partial section of the first embodiment of the utility model.
[0021] Figure 3 It is an enlarged three-dimensional view of a partial section of the second embodiment of the utility model.
[0022] Figure 4 It is an enlarged three-dimensional view of a partial section of the third embodiment of the utility model.
[0023] Figure 5 It is a partially enlarged stereoscopic view of the fourth embodiment of the utility model.
[0024] Figure 6 It is a top view of the fourth embodiment of the utility model.
[0025] Figure 7 for Figure 5 A partial enlarged schematic diagram of the position of the rightmost slide groove.
[0026] Figure 8 for Figure 5 A partial enlarged schematic diagram of the uppermost position of the slide groove.
[0027] Description of main reference numerals:
[0028] 10: Lead frame 11: Package unit pre-placement area 111: Chip seat
[0029] 112: Pin 113: Connecting rib 12: Cutting line area
[0030] 121: first cutting line area 122: second cutting line area 13: second surface
[0031] 14: Sliding knife groove 141: First sliding knife groove 142: Second sliding knife groove
[0032] 15: protruding groove 16: hollow area 161: second identification mark
[0033] 162: third identification mark 17: first identification mark 18: connecting piece
[0034] 181: Reinforcement hole L1: Groove thickness L2: Thickness
[0035] L3: Groove thickness W1: Groove width W2: Groove width. DETAILED DESCRIPTION
[0036] The technical solution of the utility model will be clearly and completely described below in conjunction with specific embodiments and accompanying drawings. It should be noted that when a component is referred to as being "mounted on or fixed to" another component, it means that it can be directly on the other component or there can also be a central component. When a component is considered to be "connected" to another component, it means that it can be directly connected to the other component or there can be a central component at the same time. In the illustrated embodiments, the directions indicating up, down, left, right, front and back are relative, and are used to explain that the structures and movements of different components in this case are relative. These representations are appropriate when the components are in the positions shown in the figures. However, if the description of the component positions changes, it is believed that these representations will also change accordingly.
[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.
[0038] like Figure 1The figure shows a plan view of the lead frame of the present invention. The lead frame structure of the present invention reduces the knife loss during singulation, wherein the lead frame 10 is a large-area metal sheet with a specific shape, and a plurality of package unit pre-placement areas 11 and a plurality of cutting line areas 12 can be defined on the lead frame 10. The plurality of package unit pre-placement areas 11 are arranged in a matrix on the lead frame 10, and the plurality of cutting line areas 12 are distributed in the area to be cut around the package unit pre-placement areas 11 in the lead frame 10. Specifically, the plurality of cutting line areas 12 include a plurality of first cutting line areas 121 and a plurality of second cutting line areas 122, and the first cutting line areas 121 and the second cutting line areas 122 are perpendicular to each other and are distributed between and around adjacent package unit pre-placement areas 11. Figure 1 Most of the structures of the package unit preset area 11 are only represented by blocks. In actual singulation, the tool will cut from the edge of the lead frame 10 to the area where the package unit preset area 11 is located, so the cutting path of the cutting line area 12 such as the first cutting line area 121 and the second cutting line area 122 also includes the area from the edge of the lead frame 10 to the package unit preset area 11. In order to reduce the knife wear during singulation, the utility model adds some special designs to the lead frame 10. The lead frame 10 also includes a plurality of sliding knife grooves 14. The sliding knife grooves 14 are formed near the edge of the lead frame 10, and each sliding knife groove 14 corresponds to the cutting path of the cutting line area 12, and the groove thickness of the sliding knife groove 14 is less than the thickness of the lead frame 10. The plurality of knife grooves 14 further include a plurality of first knife grooves 141 and a plurality of second knife grooves 142. The first knife groove 141 corresponds to the first cutting line area 121, and the second knife groove 142 corresponds to the cutting path of the second cutting line area 122. Because the thickness of the knife groove 14 is reduced, the contact area between the tool and the metal wire frame can be reduced, thereby reducing the tool wear during cutting.
[0039] Next, the structure of each embodiment of the utility model is described. Figure 2, which is a partial cross-sectional enlarged schematic diagram of the first embodiment of the utility model. Each package unit pre-placement area 11 of the lead frame 10 includes a die seat 111, a plurality of pins 112 distributed around the die seat 111, and a connecting rib 113 connected to the plurality of pins 112. In the subsequent semiconductor packaging process, die bonding, wire bonding, and encapsulation will be performed on the lead frame 10. After that, when singulating, a cutter is used to cut along the cutting line area 12 and remove the connecting rib 113 to form a single semiconductor component. This part is the same as the prior art and is only briefly described. A plurality of slide knife grooves 14 are formed near the edge of the lead frame 10, and each slide knife groove 14 is only 1-3 mm away from the edge of the lead frame 10. Each slide knife groove 14 corresponds to the cutting path of the cutting line area 12, and the groove body thickness L1 of the slide knife groove 14 is less than the thickness L2 of the lead frame 10. In this embodiment, the slide knife groove 14 with a thinner groove body thickness L1 is formed at the corresponding position of the lead frame 10 by a half-etching process. The plurality of slide knife grooves 14 also include a plurality of first slide knife grooves 141 and a plurality of second slide knife grooves 142. The first slide knife groove 141 corresponds to the cutting path of the first cutting line area 121 (indicated by an imaginary line in the figure), and the second slide knife groove 142 corresponds to the cutting path of the second cutting line area 122. Therefore, when cutting, no matter the tool cuts along the first cutting line area 121 or the second cutting line area 122 from the edge of the wire frame 10, it will quickly contact the first sliding knife groove 141 or the second sliding knife groove 142. Because the thickness here is thinner, the contact area between the tool and the metal wire frame can be reduced, which can reduce the tool wear when cutting.
[0040] In addition, the lead frame 10 has a first surface and a second surface that are opposite to each other. The first surface is the surface on which the die is placed on the die seat 111 and is also the surface on which the lead 112 is connected to the die. Figure 2 The second surface 13 of the lead frame 10 is shown in the figure. The second surface 13 is the back surface opposite to the first surface. When cutting, the cutting is generally performed from the direction of the second surface 13. The utility model should emphasize that in the present embodiment, the lead frame 10 forms a slide groove 14 on the second surface 13 by a half-etching process. The advantage is that when two-pass cutting is used, the first pass cutting depth is usually shallow, and because the lead frame 10 of the utility model forms the slide groove 14 by a half-etching method, the tool only contacts a small amount of metal at the beginning near the edge of the lead frame 10 during the first pass cutting. After reaching the slide groove 14, it only contacts the packaging colloid used for packaging, which can reduce the tool damage during the first pass cutting. Furthermore, when two-pass cutting is generally performed, the cutting width of the first pass is larger than that of the second pass cutting, and the more serious tool damage occurs in the tool of the first pass. The lead frame structure of the utility model can solve this problem.
[0041] like Figure 3As shown, it is a second embodiment of the utility model. In this embodiment, the lead frame 10 also includes a plurality of protruding grooves 15, which are connected to the slide groove 14 and are located away from the packaging unit pre-setting area 11. In this embodiment, the groove width W1 of the protruding groove 15 is smaller than the groove width W2 of the slide groove 14, and the groove body thickness L3 of the protruding groove 15 is also smaller than the thickness L2 of the lead frame 10, wherein the groove body thickness L3 of the protruding groove 15 can be the same as or different from the groove body thickness L1 of the slide groove 14. In this embodiment, the thicknesses of the two are the same, so as to complete the aforementioned structure in one half-etching process. In this example, since the groove width of the slide groove 14 is equal to or greater than the tool width of the first cutting, when there are many and thin slide grooves 14 too close to the edge of the lead frame 10, the frame strength of the lead frame 10 may be weakened, resulting in deformation of the frame of the lead frame 10 during packaging processes such as chip placement and wire bonding. Therefore, in an embodiment, a narrower protruding groove 15 is located on the side of the slide groove 14 close to the edge of the lead frame 10, and the protruding groove 15 is still a distance away from the edge of the lead frame 10. This can avoid weakening the frame strength of the lead frame 10, thereby preventing deformation of the frame of the lead frame 10 during chip placement or wire bonding.
[0042] like Figure 4 As shown, it is a third embodiment of the present invention. The wire rack 10 of the present invention also includes a plurality of hollow areas 16. Each sliding knife groove 14 has at least one hollow area 16 located in a local section thereof. The hollow area 16 is a hole that penetrates the wire rack 10. Due to the existence of the hollow area 16, when cutting, there is only a sealing gel and no metal here, thereby reducing the contact amount between the tool and the metal, and also reducing the tool wear. In addition, the hollow area 16 can also be used for identification and positioning. In the wire rack 10, each cutting line area 12 has a first identification mark 17. In this embodiment, the first identification mark 17 is a penetrating circular hole, which is used for positioning the image recognition system of the cutting tool. In this embodiment, the hollow area 16 is also a through hole, so it can be used as a second identification mark. The second identification mark is also used as a reference point for the tool to cut. The hole shape of the hollow area 16 in this embodiment can be a cross hole, an arrow hole, an elliptical hole or a geometric hole. However, when the hollow area 16 is used as the second identification mark, the hole shape of the second identification mark must be different from the first identification mark 17 to avoid misjudgment by the system. In addition, in actual operation, the location of the hollow area 16 can usually be seen in the second cutting operation, so it is mainly used as the identification system positioning for the second cutting.
[0043] like Figure 5 , Figure 6 , Figure 7 and Figure 8As shown, there are multiple schematic diagrams of the fourth embodiment of the utility model. In this embodiment, there are two hollow areas 16, which are defined as the second identification mark 161 and the third identification mark 162 in this embodiment, wherein the second identification mark 161 is located in a local area of the slide groove 14, and the third identification mark 162 is located at the junction of the slide groove 14 and the protruding groove 15. Since the protruding groove 15 is narrower than the slide groove 14, the third identification mark 162 is a cross hole in this embodiment, but it is not limited to this. In addition, in order for the system to be able to identify, the hole shapes of the two hollow areas 16 as the second identification mark 161 and the third identification mark 162 must be different from the first identification mark 17. The other two hollow areas 16 can also reduce the knife damage during cutting.
[0044] Figure 5 and Figure 6 The embodiment of the utility model is a structural diagram of the actual product. In this embodiment, the knife grooves 14 at different positions of the lead frame 10 are slightly different due to the different structures at the locations. Please refer to Figure 7 For example, in the slide groove 14 near the right edge of the lead frame 10 in the figure, there are two hollow areas 16 of different shapes forming the second identification mark 161 and the third identification mark 162, and in the slide groove 14 near the right edge of the upper edge of the lead frame 10 in the figure, there is only one hollow area 16 and the protruding groove 15. Please refer to Figure 8 As shown, in the leftmost slide groove 14 near the upper edge of the lead frame 10 in the figure, there are two hollow areas 16 of different shapes forming a second identification mark 161 and a third identification mark 162, as well as a protruding groove 15. It can be seen from this that the structure of the slide groove 14 of the utility model can add related structures according to different needs.
[0045] In addition, in each example, the lead frame 10 also includes a plurality of connecting pieces 18, which are located at the four corners of the packaging unit pre-placement area 11 and at the intersection of the two cutting line areas 12, for example, at the intersection of the first cutting line area 121 and the second cutting line area 122. The connecting piece 18 has a plurality of penetrating reinforcement holes 181. During the packaging operation, the plastic encapsulation colloid used will also fill the reinforcement holes 181. In this way, when cutting, the intersection of the two cutting line areas 12 can resist the cutting stress because of the plastic encapsulation colloid, thereby preventing the lead frame 10 from being deformed at the intersection during cutting.
[0046] In summary, the wire rack structure of the utility model reduces the knife wear during singulation, and a plurality of thinner sliding knife grooves 14 are formed near the edge of the wire rack 10, and each sliding knife groove 14 is located in the path of the corresponding cutting line area 12. In this way, due to the reduction in thickness, the knife wear during singulation can be effectively reduced, or in the second cutting operation, the chance of the knife contacting the metal during the first cutting can be reduced, and the knife wear can also be reduced. In addition, the protruding groove 15 and the plurality of hollow areas 16 can reduce the knife wear of the second cutting, and using at least one hollow area 16 as an additional identification mark can improve the positioning accuracy of the cutting position of the knife, which is innovative and practical and meets the application requirements of the patent.
[0047] The above is only the preferred embodiment of the utility model, and is not intended to limit the scope of the embodiment of the utility model. That is, all equivalent changes and modifications made according to the utility model are covered by the patent scope of the utility model.
Claims
1. A wire rack structure for reducing knife loss during singulation, comprising: Lead frame; A plurality of packaging unit preset areas are arranged in a matrix and distributed on the lead frame; A plurality of cutting line areas are defined in the area to be cut around the package unit pre-placement area in the lead frame; It is characterized in that the wire rack structure for reducing knife loss during singulation also includes a plurality of sliding knife grooves formed at the adjacent edges of the wire rack and the plurality of sliding knife grooves are all located in the paths corresponding to the cutting line areas, and the groove body thickness of the sliding knife groove is less than the thickness of the wire rack.
2. The wire rack structure for reducing knife loss during singulation as claimed in claim 1, characterized in that: The lead frame has a first surface and a second surface that are opposite to each other. The cutting is performed from the direction of the second surface. The lead frame is subjected to a half-etching process on the second surface to form the knife groove.
3. The wire rack structure for reducing knife loss during singulation as claimed in claim 1, characterized in that: The lead frame is formed with at least one protruding groove, the protruding groove is connected to the sliding knife groove and is located away from the packaging unit pre-placement area, and the groove width of the protruding groove is smaller than the groove width of the sliding knife groove.
4. The wire rack structure for reducing knife loss during singulation as claimed in claim 3, characterized in that: The thickness of the protruding groove is the same as or different from the groove thickness of the sliding knife groove, and the groove thickness of the protruding groove is also smaller than the thickness of the lead frame.
5. The wire rack structure for reducing knife loss during singulation as claimed in claim 3, characterized in that: The protruding groove is at a distance from the edge of the lead frame.
6. The wire rack structure for reducing knife loss during singulation as claimed in claim 1, characterized in that: The lead frame forms a plurality of hollow areas, the slide knife groove has at least one hollow area, the hollow area is located in a local section of the slide knife groove, and the hollow area is a hole that penetrates the lead frame.
7. The lead frame structure for reducing knife loss during singulation as claimed in claim 6, characterized in that: The lead frame has a plurality of first identification marks, each of which is used for identifying and locating the corresponding cutting line area. The hollow area serves as a second identification mark, and the shape of the second identification mark is different from that of the first identification mark.
8. The lead frame structure for reducing knife loss during singulation as claimed in claim 6, characterized in that: The hollow area is located in the sliding knife groove and is far away from the packaging unit pre-placement area.
9. The wire rack structure for reducing knife loss during singulation as claimed in claim 7 or 8, characterized in that: The hollow area is a cross-shaped hole, an arrow-shaped hole or an elliptical hole.
10. The lead frame structure for reducing knife loss during singulation as claimed in claim 7, characterized in that: The slide knife groove has a plurality of hollow areas, and when the plurality of hollow areas are used as identification marks, the shapes of the plurality of identification marks are different from the shape of the first identification mark.
11. The wire rack structure for reducing knife loss during singulation as claimed in claim 1, characterized in that: The lead frame also includes a plurality of connecting pieces, which are located at the four corners of the packaging unit pre-set area and at the intersection of the two cutting line areas. The connecting pieces have a plurality of penetrating reinforcement holes. During the packaging operation, the plastic encapsulation colloid used fills the reinforcement holes.
12. The wire rack structure for reducing knife loss during singulation as claimed in claim 1, characterized in that: The multiple cutting line areas include multiple first cutting line areas and multiple second cutting line areas, the first cutting line areas and the second cutting line areas are perpendicular to each other, and the multiple sliding knife grooves include a first sliding knife groove and a second sliding knife groove, the first sliding knife groove is located in the cutting path of the first cutting line area, and the second sliding knife groove is located in the cutting path of the second cutting line area.