A DFN or QFN lead frame structure preventing metal residue after cutting

Abstract

The utility model discloses a prevent DFN or QFN lead frame structure after cutting has metal residue, including frame substrate, and be located on the frame substrate on a plurality of matrix arrangement's lead frame unit, be equipped with first connecting muscle between two rows of lead frame unit of adjacent, be equipped with second connecting muscle between two columns of lead frame unit of adjacent, the intersection of first connecting muscle and second connecting muscle is connected and forms cross -shaped structure, the both sides lateral wall of one end of first connecting muscle close to cross -shaped structure all recessed has first gap, first gap has first inner lateral wall, the both sides lateral wall of one end of second connecting muscle close to cross -shaped structure all recessed has second gap, second gap has second inner lateral wall, first gap and adjacent second gap form the slot of communicating, form the circular segment between first inner lateral wall and adjacent second inner lateral wall, the utility model discloses when cutting, can cut off the metal material of circular segment completely, avoid metal and remain on product.

Description

Technical Field

[0001] This utility model relates to the field of integrated circuit packaging technology, specifically to a DFN or QFN lead frame structure that prevents metal residue after cutting. Background Technology

[0002] The current DFN / QFN products are obtained by a series of production processes such as chip mounting, bonding, molding, and cutting of DFN / QFN lead frames. DFN / QFN lead frames generally have multiple lead frame units. Adjacent lead frame units are provided with longitudinal and transverse connecting ribs. The longitudinal and transverse connecting ribs intersect to form a cross-shaped structure. In order to meet the requirements of the production process, the corners at the intersection of the longitudinal and transverse connecting ribs are usually provided with a certain length of arc segment. After molding, the longitudinal and transverse connecting ribs are cut off one by one with a cutting blade to obtain several independent finished products.

[0003] However, currently, the cutting precision of the cutting blade has a tolerance of ±50µm. This means that the cutting position of the cutting blade will deviate by up to 50µm. When the cutting position of the cutting blade deviates by 50µm, the metal material in the arc segment will not be completely removed, resulting in metal residue on the product and affecting its subsequent use. Utility Model Content

[0004] This invention addresses the shortcomings of existing technologies by providing a DFN or QFN lead frame structure that prevents metal residue after cutting. During cutting, the metal material in the arc segment can be completely removed, avoiding metal residue on the product.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A DFN or QFN lead frame structure to prevent metal residue after cutting includes a frame substrate and a plurality of lead frame units arranged in a matrix on the frame substrate. A first connecting rib is provided between two adjacent rows of the lead frame units, and a second connecting rib is provided between two adjacent columns of the lead frame units. The intersection of the first connecting rib and the second connecting rib is connected to form a cross-shaped structure.

[0007] The first connecting rib has a first notch recessed on both sides of the end near the cross-shaped structure, and the first notch has a first inner sidewall.

[0008] The second connecting rib has a second notch recessed on both sides of the end near the cross-shaped structure, and the second notch has a second inner sidewall.

[0009] The first notch connects with the adjacent second notch to form a notch, and an arc segment is formed between the first inner sidewall and the adjacent second inner sidewall, the arc segment being located in the notch.

[0010] By setting first notches on both side walls of the first connecting rib near the cross-shaped structure, each notch having a first inner sidewall, and setting second notches on both side walls of the second connecting rib near the cross-shaped structure, each notch having a second inner sidewall, the first notches and adjacent second notches are connected to form a notch. An arc segment is formed between the first inner sidewall and the adjacent second inner sidewall, and the arc segment is located in the notch. The first and second connecting ribs are narrowed near the cross-shaped structure to form a concave structure, ensuring that the arc segment has a certain length to meet the production process requirements, while making the position of the arc segment closer to the center of the cross-shaped structure. Thus, when the cutting blade has a maximum positional offset of 50µm, the arc segment is still entirely within the cutting range of the cutting blade, thereby ensuring that the arc segment can be completely removed and avoiding metal residue on the product.

[0011] In one embodiment, the arc length S of the arc segment is 0.2 mm to 0.4 mm.

[0012] In one embodiment, the width b1 of the first connecting rib is 0.18 mm to 0.22 mm, and the height difference h1 between the first inner sidewall and the sidewall of the first connecting rib is 0.015 mm to 0.05 mm.

[0013] In one embodiment, the width of the second connecting rib is b2 = b1, and the height difference between the second inner sidewall and the sidewall of the second connecting rib is h2 = h1.

[0014] In one embodiment, the distance k1 between two opposing first inner sidewalls is 0.12 mm to 0.15 mm, and the distance k2 between two opposing second inner sidewalls is 0.12 mm to 0.15 mm.

[0015] In one embodiment, the length L1 of the first inner sidewall is 0.1 mm to 0.25 mm.

[0016] In one embodiment, the plane containing the first inner sidewall is parallel to the extension direction of the first connecting rib, and the first inner sidewall is perpendicular to the adjacent second inner sidewall.

[0017] Compared with the prior art, this utility model has significant advantages and beneficial effects. Specifically, by setting a first notch on both side walls of the first connecting rib near the cross-shaped structure, with a first inner sidewall inside the first notch, and setting a second notch on both side walls of the second connecting rib near the cross-shaped structure, with a second inner sidewall inside the second notch, the first notch and the adjacent second notch are connected to form a notch. An arc segment is formed between the first inner sidewall and the adjacent second inner sidewall, and the arc segment is located in the notch. The first and second connecting ribs are narrowed near the cross-shaped structure to form a concave structure, ensuring that the arc segment has a certain length to meet the production process requirements, while making the position of the arc segment closer to the center of the cross-shaped structure. Thus, when the cutting blade has a maximum positional offset of 50µm, the arc segment is still entirely within the cutting range of the cutting blade, thereby ensuring that the arc segment can be completely removed and avoiding metal residue on the product.

[0018] To more clearly illustrate the structural features, technical means, and specific objectives and functions achieved by this utility model, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments: Attached Figure Description

[0019] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model;

[0020] Figure 2 This is a schematic diagram of the connection between the first connecting rib and the second connecting rib in an embodiment of this utility model;

[0021] Figure 3 yes Figure 2 A magnified view of part C in the middle;

[0022] Figure 4 This is a schematic diagram of the normal cutting state of the cutting blade according to an embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of the cutting state when the cutting blade is offset by a maximum of 50µm according to an embodiment of this utility model.

[0024] Explanation of reference numerals in the attached diagram:

[0025] 10-Frame substrate, 11-Lead frame unit, 12-First connecting rib, 13-Second connecting rib, 14-Cross-shaped structure, 15-First notch, 151-First inner sidewall, 16-Second notch, 161-Second inner sidewall, 17-Groove, 18-Arc segment, 20-Cutting blade. Detailed Implementation

[0026] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "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 the utility model and simplifying the description, and do not indicate or imply that the position 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 utility model.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0028] like Figure 1-5 As shown, this utility model discloses a DFN or QFN lead frame structure to prevent metal residue after cutting, including a frame substrate 10 and a plurality of lead frame units 11 arranged in a matrix on the frame substrate 10. The lead frame units 11 are arranged in multiple rows along the width direction A of the frame substrate 10 and in multiple columns along the length direction B of the frame substrate 10. A first connecting rib 12 is provided between two adjacent rows of the lead frame units 11, and a second connecting rib 13 is provided between two adjacent columns of the lead frame units 11. The intersection of the first connecting rib 12 and the second connecting rib 13 is connected to form a cross-shaped structure 14.

[0029] The first connecting rib 12 has a first notch 15 recessed on both sides of the end near the cross-shaped structure 14, and the first notch 15 has a first inner sidewall 151.

[0030] The second connecting rib 13 has a second notch 16 recessed on both sides of the end near the cross-shaped structure 14, and the second notch 16 has a second inner sidewall 161.

[0031] The first notch 15 is connected to the adjacent second notch 16 to form a notch 17. An arc segment 18 is formed between the first inner sidewall 151 and the adjacent second inner sidewall 161, and the arc segment 18 is located in the notch 17.

[0032] The arc length S of the arc segment 18 is 0.2mm to 0.4mm. By using an arc segment 18 with an arc length S of 0.2mm to 0.4mm, it is ensured that the arc segment 18 can meet the production process requirements. Even when the cutting blade 20 has a maximum positional offset of 50um, the arc segment 18 is still entirely within the cutting range of the cutting blade 20 (it should be noted that the cutting range is defined as the sum of the range of the cutting blade 20 cutting the first connecting rib 12 and the range of the second connecting rib 13), thereby ensuring that the arc segment 18 can be completely removed and avoiding metal residue on the product.

[0033] The width b1 of the first connecting rib 12 is 0.18mm to 0.22mm, and the height difference h1 between the first inner sidewall 151 and the sidewall of the first connecting rib 12 is 0.015mm to 0.05mm. By setting the height difference h1 between the first inner sidewall 151 and the sidewall of the first connecting rib 12 to 0.015mm to 0.05mm, the length requirement of the arc length S of the arc segment 18 can be met.

[0034] The width of the second connecting rib 13 is b2 = b1, and the height difference between the second inner sidewall 161 and the sidewall of the second connecting rib 13 is h2 = h1.

[0035] The distance k1 between the two opposing first inner sidewalls 151 is 0.12mm to 0.15mm, and the distance k2 between the two opposing second inner sidewalls 161 is 0.12mm to 0.15mm. By setting the distance k1 between the two opposing first inner sidewalls 151 to 0.12mm to 0.15mm, it is ensured that the first connecting rib 12 has sufficient connection strength at its narrowest point, and the same applies to the second connecting rib 13.

[0036] The length L1 of the first inner sidewall 151 is 0.1mm to 0.25mm, and the length direction of the first inner sidewall 151 is the same as the extension direction of the first connecting rib 12. The length L2 of the second inner sidewall 161 is L1. By setting the first inner sidewall 151 with a length L1 of 0.1mm to 0.25mm, the first notch 15 has sufficient length to form an arc segment.

[0037] The plane containing the first inner sidewall 151 is parallel to the extension direction of the first connecting rib 12, and the first inner sidewall 151 is perpendicular to the adjacent second inner sidewall 161.

[0038] like Figure 5 As shown, when the cutting blade 20 is offset by a maximum of 50µm, the arc segment 18 is completely within the cutting range of the cutting blade 20.

[0039] In summary, this utility model provides first notches 15 on both sides of the first connecting rib 12 near the cross-shaped structure 14, with a first inner sidewall 151 inside each notch. Similarly, it provides second notches 16 on both sides of the second connecting rib 13 near the cross-shaped structure 14, with a second inner sidewall 161 inside each notch. The first notches 15 and adjacent second notches 16 connect to form a notch 17. An arc segment 18 is formed between the first inner sidewall 151 and adjacent second inner sidewall 161, located within the notch 17. By narrowing the first and second connecting ribs 12 and 13 near the cross-shaped structure 14 to form a recessed structure, the arc segment 18 is ensured to have a certain length to meet production process requirements while being closer to the center of the cross-shaped structure 14. Therefore, even when the cutting blade 20 experiences a maximum positional shift of 50µm, the arc segment 18 remains entirely within the cutting range of the cutting blade 20, ensuring complete removal of the arc segment 18 and preventing metal residue on the product.

[0040] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Therefore, any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the actual technical aspects of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A DFN or QFN lead frame structure to prevent metal residue after cutting, characterized in that, It includes a frame substrate and a plurality of lead frame units arranged in a matrix on the frame substrate. A first connecting rib is provided between two adjacent rows of the lead frame units, and a second connecting rib is provided between two adjacent columns of the lead frame units. The intersection of the first connecting rib and the second connecting rib is connected to form a cross-shaped structure. The first connecting rib has a first notch recessed on both sides of the end near the cross-shaped structure, and the first notch has a first inner sidewall. The second connecting rib has a second notch recessed on both sides of the end near the cross-shaped structure, and the second notch has a second inner sidewall. The first notch connects with the adjacent second notch to form a notch, and an arc segment is formed between the first inner sidewall and the adjacent second inner sidewall, the arc segment being located in the notch.

2. The DFN or QFN lead frame structure for preventing metal residue after cutting according to claim 1, characterized in that, The arc length S of the arc segment is 0.2mm to 0.4mm.

3. The DFN or QFN lead frame structure for preventing metal residue after cutting according to claim 1, characterized in that, The width b1 of the first connecting rib is 0.18mm to 0.22mm, and the height difference h1 between the first inner sidewall and the sidewall of the first connecting rib is 0.015mm to 0.05mm.

4. The DFN or QFN lead frame structure for preventing metal residue after cutting according to claim 3, characterized in that, The width of the second connecting rib is b2 = b1, and the height difference between the second inner sidewall and the sidewall of the second connecting rib is h2 = h1.

5. The DFN or QFN lead frame structure for preventing metal residue after cutting according to claim 1, characterized in that, The distance k1 between two opposing first inner sidewalls is 0.12mm to 0.15mm, and the distance k2 between two opposing second inner sidewalls is 0.12mm to 0.15mm.

6. The DFN or QFN lead frame structure for preventing metal residue after cutting according to claim 1, characterized in that, The length L1 of the first inner sidewall is 0.1mm to 0.25mm.

7. The DFN or QFN lead frame structure for preventing metal residue after cutting according to claim 1, characterized in that, The plane containing the first inner sidewall is parallel to the extension direction of the first connecting rib, and the first inner sidewall is perpendicular to the adjacent second inner sidewall.

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