Ultra-narrow semiconductor lead frame

Abstract

The utility model provides an ultra-narrow semiconductor lead frame, which comprises a lead frame monomer having a length direction and a width direction, and the width direction of the lead frame monomer is smaller than the length direction of the lead frame monomer; each lead frame monomer comprises a base made of a conductor material and a cup body which is made of an insulating material and is combined with the base through a glue injection process; the cup body is of an open structure, the bottom of the cup body is provided with an insulating separation belt integrally formed with the cup body through glue injection, and the insulating separation belt is obliquely arranged in the width direction of the lead frame single body and forms a cup bottom structure of the cup body together with the base. And the area of the base on the inner side of the cup body is separated by the insulating separation strip to form a first bonding pad on one side of the insulating separation strip and a second bonding pad on the other side of the insulating separation strip. According to the structural design of the utility model, the structural stability of the whole lead frame monomer can be ensured, and the lead frame monomer can be narrower, so that the cost of the light guide plate is reduced by about 1 / 4, and the competitiveness of the product is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of LEDs, in particular to an ultra-narrow semiconductor lead frame. Background Art

[0002] Lead frame is the basic material for semiconductor IC and device molding packaging. Lead frame has three main functions:

[0003] 1. Provide mechanical support for the chip, which relies on the support of the frame during potting and subsequent use;

[0004] 2. Provide electrical connection, communicate chip and external circuit, all signals and power are transmitted through pins;

[0005] 3. Provide heat dissipation path. The pins have lower thermal resistance than plastic packaging and are the main heat dissipation channel.

[0006] Semiconductor devices need to be installed on a circuit board PCB during use, and this relies on pins being soldered and fixed to pads. The pins are provided by the lead frame.

[0007] In order to ensure the stability and strength of the structure, the width of the traditional lead frame monomer is generally more than 1.5 mm. Lead frame monomers of this width are relatively common in the market, but are not competitive in the market. Utility Model Content

[0008] In order to solve the technical problems existing in the background technology, the utility model proposes an ultra-narrow semiconductor lead frame.

[0009] The utility model provides an ultra-narrow semiconductor lead frame, comprising:

[0010] The lead frame monomer has a length direction and a width direction, wherein the width direction is smaller than the length direction and the width is smaller than 1.25 mm; the lead frame monomer comprises a base made of a conductive material and a cup body combined with the base by an insulating material through a glue injection process;

[0011] The cup body is an open-mouth structure, and the bottom thereof has an insulating separation strip which is integrally formed by injection molding, and the insulating separation strip is arranged obliquely along the width direction of the lead frame monomer and together with the base constitutes the cup bottom structure of the cup body;

[0012] The area of ​​the base located inside the cup body is separated by an insulating separation zone to form a first welding pad located on one side of the insulating separation zone and a second welding pad located on the other side of the insulating separation zone.

[0013] Preferably, the length of the lead frame monomer is greater than 3.90 mm, the inner cup mouth width of the cup body is less than 0.95 mm, the width of the inner side wall of the cup bottom is less than 0.80 mm, and the thickness of the side wall of the cup body is greater than 150 um.

[0014] Preferably, the inclination angle of the insulating separation zone is greater than 70° and less than 90°.

[0015] Preferably, a package moisture-proof groove body is provided at the base at the joint surface between the base and the cup body and at the end away from the first pad and the second pad, and the package moisture-proof groove body includes at least one groove arranged along the width direction of the lead frame.

[0016] Preferably, the base has a depression surface arranged along its contour edge on a side away from the cup mouth of the cup body and lower than its surface to form a height difference with its surface, and the cup body wraps the depression surface inside it during the injection molding process so that the depression surface is embedded in the cup body.

[0017] Preferably, an extrusion groove formed by pressing inward is provided on the outer side wall of the lead frame monomer in the length direction and at the junction of the base and the cup body, and the extrusion groove is a linear groove extending along the length direction of the lead frame monomer.

[0018] Preferably, the center portion of the base toward the end is higher than the two side portions thereof to form a convex surface, and the end surface of the convex surface is plated with a silver layer.

[0019] Preferably, it also includes a conductive substrate constituting the base, the conductive substrate is stamped to form a plurality of single base stamping areas, each single base stamping area has a groove penetrating the conductive substrate, the groove includes a first groove cavity and a second groove cavity that are arranged opposite to each other, and an isolation groove located between the first groove cavity and the second groove cavity and connecting the two, and the area of ​​the single base stamping area located on both sides of the isolation groove constitutes a first pad and a second pad in the lead frame monomer;

[0020] Every N single base stamping areas form a group, all the single base stamping areas in each group are arranged linearly, and a connecting bridge connecting the grooves of the two adjacent single base stamping areas in each group is provided; the central part of the connecting bridge has a glue injection port for injecting insulating material; each group of two adjacent single base stamping areas is glued through the glue injection port located between the two to form a cup body in each single base stamping area, and each cup body is respectively combined with the single base stamping area located at the bottom thereof to form lead frame monomers on the conductive substrate.

[0021] Preferably, the conductive substrate is a strip-shaped metal sheet having a length direction and a width direction. In its width direction, a spacing is reserved between any two adjacent groups of single base stamping area groups to form a longitudinal spacing zone. In its length direction, a spacing is reserved between any two adjacent groups of single base stamping area groups to form a transverse spacing zone, and a through hole is provided at the intersection of any transverse isolation zone and the longitudinal isolation zone.

[0022] Preferably, cutouts are provided on both the length side and the width side of the conductive substrate, and the center of the cutout on the length side is located on the center line of the longitudinal isolation zone, and the center of the cutout on the width side is located on the center line of the transverse isolation zone, and the shapes of the cutouts on the length side and the width side are different.

[0023] Preferably, the shape of the cutout on one length edge of the conductive substrate is V-shaped, and the port edges on both sides of the V-shape are provided with C chamfers.

[0024] Preferably, the cutout shape of the other length side of the conductive substrate is a trapezoid.

[0025] Preferably, the cutouts on the width sides of the conductive substrate are semicircular.

[0026] The utility model arranges the insulating separation strip obliquely along the width direction of the lead frame monomer, and this arrangement can make up for the problem that the combined area of ​​the base and the cup body is insufficiently reduced due to the narrowing of the width of the lead frame monomer, and the structural stability and strength are weakened. Then, while ensuring the structural stability of the entire lead frame monomer, the lead frame monomer can be made narrower in width. By reducing the width of the product, the 2.0mm light guide plate conventionally used in the back end can be replaced with a light guide plate with a width specification of 1.5mm, and the direct cost of the light guide plate is reduced by about 1 / 4, which greatly improves the competitiveness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a front view of the lead frame monomer in the ultra-narrow semiconductor lead frame proposed by the utility model;

[0028] Figure 2 A top view of a lead frame unit in an ultra-narrow semiconductor lead frame proposed by the utility model;

[0029] Figure 3 A side view of a lead frame unit in an ultra-narrow semiconductor lead frame proposed by the utility model;

[0030] Figure 4 It is a partial schematic diagram of the conductive substrate in the ultra-narrow semiconductor lead frame proposed by the utility model;

[0031] Figure 5It is a structural schematic diagram of a single base stamping area in a conductive substrate in an ultra-narrow semiconductor lead frame proposed by the utility model;

[0032] Figure 6 This is a schematic structural diagram of the conductive substrate in the ultra-narrow semiconductor lead frame proposed by the utility model after the glue injection process is completed;

[0033] Figure 7 This is a schematic diagram of the combination state of the single base stamping area and the cup body after the ultra-narrow semiconductor lead frame is injected with glue proposed by the utility model;

[0034] Figure 8 The present invention is a schematic diagram of the arrangement of the lead frame monomers on a conductive substrate in an ultra-narrow semiconductor lead frame proposed by the present invention. DETAILED DESCRIPTION

[0035] Reference Figure 1-3 The utility model proposes an ultra-narrow semiconductor lead frame, comprising: a lead frame monomer 1, which has a length direction and a width direction, and its width direction is smaller than its length direction, and its width is less than 1.25mm; the lead frame monomer 1 includes a base 11 made of a conductive material and a cup body 12 combined with the base 11 by an insulating material through a glue injection process.

[0036] The cup body 12 is an open structure, and its bottom has an insulating separation strip 121 integrally formed with the insulating separation strip, and the insulating separation strip 121 is arranged obliquely along the width direction of the lead frame monomer 1 and together with the base 11 constitutes the cup bottom structure of the cup body 12. The area of ​​the base 11 located inside the cup body 12 is separated by the insulating separation strip 121 to form a first pad 111 located on one side of the insulating separation strip 121 and a second pad 112 located on the other side of the insulating separation strip 121.

[0037] The utility model arranges the insulating separation strip 121 obliquely along the width direction of the lead frame monomer 1. This arrangement can compensate for the problem that the bonding area between the base 11 and the cup body 12 is insufficiently reduced due to the narrowing of the width of the lead frame monomer 1, and the structural stability and strength are weakened. Then, while ensuring the structural stability of the entire lead frame monomer 1, the lead frame monomer 1 can be made narrower in width. By reducing the width of the product, the 2.0mm light guide plate conventionally used in the back end can be replaced with a light guide plate with a width specification of 1.5mm, and the direct cost of the light guide plate is reduced by about 1 / 4, which greatly improves the competitiveness of the product.

[0038] Specifically, in this embodiment, the length of the lead frame monomer 1 is greater than 3.90 mm, the inner cup width of the cup body 12 is less than 0.95 mm, the inner side wall width of the cup bottom is less than 0.80 mm, and the side wall thickness of the cup body 12 is greater than 150 μm. The inclination angle of the insulating separation zone 121 is greater than 70° and less than 90°.

[0039] In addition, as the width of the lead frame monomer 1 becomes narrower, the bonding surface between the cup body 12 and the base 11 will also decrease, which weakens the bonding strength between the two in the width direction. Therefore, in this embodiment, a package moisture-proof groove 113 is provided at the end of the base 11 located at the bonding surface between the cup body 12 and the first pad 111 and the second pad 112, and the package moisture-proof groove 113 includes at least one groove provided along the width direction of the lead frame. By adding grooves in the width direction, the missing part of the bonding area after narrowing is compensated, and then the bonding strength between the cup body 12 and the base 11 is guaranteed.

[0040] Furthermore, the side of the base 11 located away from the cup mouth of the cup body 12 has a sinking surface 114 arranged along its contour edge and lower than its surface to form a height difference with its surface, and the cup body 12 wraps the sinking surface 114 inside it during the injection molding process so that the sinking surface 114 is embedded in the cup body 12. The specific formation method is: during the injection molding process of the cup body 12, part of the insulating material enters the sinking surface 114, thereby causing the sinking surface 114 to be coated, and then after the insulating material is solidified, the sinking is wrapped in the cup body 12. This structural design can not only further increase the bonding strength between the base 11 and the cup body 12, but also improve the airtightness of the bonding surface between the cup body 12 and the base 11, so as to prevent foreign substances from entering the cup body 12 from the bonding surface between the two.

[0041] In addition, in this embodiment, the lead frame monomer 1 is provided with an extrusion groove formed by pressing inward at the outer side wall in the length direction and at the junction of the base 11 and the cup body 12, and the extrusion groove is a linear groove extending along the length direction of the lead frame monomer 1. This further increases the strength of the junction between the base 11 and the cup body 12, improves stress deformation, and enables the lead frame monomer 1 to maintain good strength and anti-deformation ability when its width is narrowed, thereby ensuring product quality.

[0042] In this embodiment, the center portion of the base 11 toward the end is higher than the two side portions thereof to form a raised surface 115, and the end surface of the raised surface 115 is plated with a silver layer. This structural design has the following advantages:

[0043] 1. Improve heat dissipation efficiency: LED generates heat during operation. The protrusion in the middle of the base 11 can increase the heat sink area, which helps to conduct the heat generated by the LED chip to the external environment more quickly, thereby effectively reducing the temperature of the LED and extending its service life;

[0044] 2. Enhanced mechanical strength: The protruding convex surface 115 can increase the structural strength of the welding part to prevent the LED chip from having poor contact with the circuit board or falling off due to external force;

[0045] 3. Improve electrical connection: The protruding convex surface 115 increases the contact area with the PCB board, which is beneficial to the flow of current and heat dissipation, reduces resistance loss, and improves the stability of electrical performance;

[0046] 4. Reduce contact resistance: Silver is one of the best known metals for electrical conductivity, and its resistivity is extremely low. After the raised surface 115 is fully plated with silver, the contact resistance of the welding point can be significantly reduced, the current transmission efficiency can be improved, and the energy loss can be reduced;

[0047] 5. Enhance welding effect: Silver has good wettability and solderability, which can make solder easier to adhere and fully fill between the pad and the LED pin, thereby improving welding quality and reliability;

[0048] 6. Improve heat dissipation performance: Silver has excellent thermal conductivity. The fully silver-plated raised surface 115 can more effectively conduct the heat generated by the LED to the PCB board or other heat dissipation system, which helps to reduce the operating temperature of the LED chip and extend its service life;

[0049] 7. Anti-oxidation and anti-corrosion: The silver coating can effectively prevent the oxygen and moisture in the air from oxidizing and corroding the raised surface 115, protect the welding parts from environmental influences, and maintain a long-term stable working state.

[0050] Reference Figure 4-8 The utility model provides an ultra-narrow semiconductor lead frame, which also includes a conductive substrate 2 constituting a base 11. The conductive substrate 2 is punched to form a plurality of single base punching areas 21. Each single base punching area 21 has a groove 3 penetrating the conductive substrate 2. The groove 3 includes a first groove cavity and a second groove cavity that are arranged opposite to each other, and an isolation groove between the first groove cavity and the second groove cavity and connecting the two. The area of ​​the single base punching area 21 located on both sides of the isolation groove constitutes a first pad 111 and a second pad 112 in the lead frame monomer 1.

[0051] Every N single base stamping areas 21 form a group, and all the single base stamping areas 21 in each group are arranged linearly, and a connecting bridge 4 for connecting the two grooves 3 is provided between each group of adjacent single base stamping areas 21; the central part of the connecting bridge 4 has a glue injection port 5 for injecting insulating material; each group of adjacent two single base stamping areas 21 is injected with glue through the glue injection port 5 located between the two to form a cup body 12 in each single base stamping area 21, and each cup body 12 is respectively combined with the single base stamping area 21 located at the bottom thereof to form a lead frame monomer 1 on the conductive substrate 2.

[0052] This method of symmetrical grouping: taking a group as a whole, symmetrically grouping according to the maximum number that can be arranged according to the width of the conductive substrate 2, all the single base stamping areas 21 between each group are interconnected via a connecting bridge, and only the material rods at both ends are used to support the material sheet to ensure strength. Compared with the traditional closed single arrangement method, it has the following advantages:

[0053] 1. Compared with the traditional arrangement, this arrangement method has about 10% more lead frame monomers 1 arranged on the conductive substrate 2 of the same specification, and each group of products is interconnected in the middle, which can better resist material bending and deformation and release excess stress;

[0054] 2. The overall weight is reduced. With the same total weight of shipping packaging, the shipping quantity increases by about 15%, reducing transportation costs;

[0055] 3. More raw materials are recovered, which can reduce production costs in mass production.

[0056] Furthermore, the conductive substrate 2 is a strip-shaped metal sheet having a length direction and a width direction, and in the width direction, any two adjacent groups of single base stamping areas 21 are reserved with a spacing to form a longitudinal spacing zone, and in the length direction, any two adjacent groups of single base stamping areas 21 are reserved with a spacing to form a transverse spacing zone, and any intersection of a transverse isolation zone and a longitudinal isolation zone is provided with a through hole 6. This is conducive to further reducing the overall weight of the conductive substrate 2 and recycling more raw materials, and is also convenient for disassembly and positioning in the later stage.

[0057] Furthermore, the conductive substrate 2 is provided with cutouts 7 on both the length side and the width side, and the center of the cutout 7 on the length side is located on the center line of the longitudinal isolation zone, and the center of the cutout 7 on the width side is located on the center line of the transverse isolation zone, and the shapes of the cutouts 7 on the length side and the width side are different. This design further reduces the weight of the product and uses the difference in the shapes of the cutouts 7 on the length side and the width side to quickly identify the direction.

[0058] Furthermore, the shape of the cutout 7 on one length side of the conductive substrate 2 is V-shaped. The design of the V-shaped cutout 7 has the following advantages:

[0059] 1. In the back-end application, the V-shaped cutting edge can eliminate sharp edges, improve the safety of operators and users, and avoid the sharp edges of the material edge in the back-end application may cause metal debris to fall, resulting in product short circuit, affecting the product light effect and other adverse effects;

[0060] 2. Compared with right-angle edges, V-shaped cut edges can disperse stress and reduce the risk of cracks or fractures caused by stress concentration;

[0061] 3. V-shaped cutting can reduce the thickness of the edge of the sheet, thereby reducing the weight of the overall structure;

[0062] 4. Although cutting reduces material, the V-shaped design may actually increase local stiffness. By cutting into a V shape, a rib-like effect is formed at the edge, which can improve the component's ability to resist bending moments.

[0063] In addition, the port edges on both sides of the V-shaped incision 7 are provided with C chamfers. By setting the port edges as C chamfers, the smoothness of the edge of the conductive substrate 2 is ensured, and the sharp corners of the edges are prevented from scratching other adjacent product parts during processing or batch transportation, causing metal debris and scratches to expose copper.

[0064] Furthermore, the shape of the cutout 7 on the other length side of the conductive substrate 2 is trapezoidal, which makes the shapes of the cutouts 7 on the length sides of the conductive substrate 2 different. This design facilitates quick identification of the direction of the length side of the conductive substrate 2.

[0065] Furthermore, the cutout 7 on the width side of the conductive substrate 2 is semicircular.

[0066] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An ultra-narrow semiconductor lead frame, characterized in that: A lead frame monomer (1) has a length direction and a width direction, wherein the width direction is smaller than the length direction and the width is smaller than 1.25 mm; the lead frame monomer (1) comprises a base (11) made of a conductive material and a cup body (12) made of an insulating material and combined with the base (11) by a glue injection process; The cup body (12) is an open structure, and has an insulating separation strip (121) formed integrally with the cup body by injection molding at its bottom, and the insulating separation strip (121) is arranged obliquely along the width direction of the lead frame monomer (1) and together with the base (11) forms a cup bottom structure of the cup body (12); The area of ​​the base (11) located inside the cup body (12) is separated by an insulating separation zone (121) to form a first welding pad (111) located on one side of the insulating separation zone (121) and a second welding pad (112) located on the other side of the insulating separation zone (121).

2. The ultra-narrow semiconductor lead frame according to claim 1, characterized in that: The length of the lead frame monomer (1) is greater than 3.90 mm, the inner cup opening width of the cup body (12) is less than 0.95 mm, the width of the inner side wall of the cup bottom is less than 0.80 mm, and the thickness of the side wall of the cup body (12) is greater than 150 μm.

3. The ultra-narrow semiconductor lead frame according to claim 1, characterized in that: The inclination angle of the insulating separation zone (121) is greater than 70° and less than 90°.

4. The ultra-narrow semiconductor lead frame according to claim 1, characterized in that: A package moisture-proof groove body (113) is provided on the base (11) at the joint surface between the base (11) and the cup body (12) and at an end position away from the first solder pad (111) and the second solder pad (112). The package moisture-proof groove body (113) comprises at least one groove arranged along the width direction of the lead frame.

5. The ultra-narrow semiconductor lead frame according to claim 1, characterized in that: The base (11) has a depression surface (114) disposed along its contour edge and lower than its surface to form a height difference with the surface on a side thereof that is located away from the cup mouth of the cup body (12); and the cup body (12) wraps the depression surface (114) inside thereof during the injection molding process so that the depression surface (114) is embedded in the cup body (12).

6. The ultra-narrow semiconductor lead frame according to claim 1, characterized in that: The lead frame monomer (1) is provided with an extrusion groove formed by pressing inward on its outer side wall in the length direction and at the junction of its base (11) and cup body (12), and the extrusion groove is a linear groove extending along the length direction of the lead frame monomer (1).

7. The ultra-narrow semiconductor lead frame according to claim 1, characterized in that: The center portion of the base (11) toward the end is higher than the two side portions thereof to form a convex surface (115), and the end surface of the convex surface (115) is plated with a silver layer.

8. The ultra-narrow semiconductor lead frame according to any one of claims 1 to 7, characterized in that: It also includes a conductive substrate (2) constituting a base (11), wherein the conductive substrate (2) is punched to form a plurality of single base punching areas (21), each single base punching area (21) having a groove (3) penetrating the conductive substrate (2), the groove (3) comprising a first groove cavity and a second groove cavity arranged opposite to each other, and an isolation groove located between the first groove cavity and the second groove cavity and connecting the two, and the areas of the single base punching area (21) located on both sides of the isolation groove constitute a first solder pad (111) and a second solder pad (112) in the lead frame monomer (1); Every N single base stamping areas (21) form a group, all the single base stamping areas (21) in each group are arranged linearly, and a connecting bridge (4) for connecting the two grooves (3) is provided between two adjacent single base stamping areas (21) in each group; the central part of the connecting bridge (4) has a glue injection port (5) for injecting insulating material; each group of two adjacent single base stamping areas (21) is injected with glue through the glue injection port (5) located between the two to form a cup body (12) in each single base stamping area (21), and each cup body (12) is respectively combined with the single base stamping area (21) located at the bottom thereof to form lead frame monomers (1) on the conductive substrate (2).

9. The ultra-narrow semiconductor lead frame according to claim 8, characterized in that: The conductive substrate (2) is a strip-shaped metal sheet having a length direction and a width direction. In the width direction, a spacing is reserved between any two adjacent groups of single base stamping areas (21) to form a longitudinal spacing zone. In the length direction, a spacing is reserved between any two adjacent groups of single base stamping areas (21) to form a transverse spacing zone. A through hole (6) is provided at the intersection of any transverse isolation zone and the longitudinal isolation zone.

10. The ultra-narrow semiconductor lead frame according to claim 9, characterized in that: The conductive substrate (2) is provided with cutouts (7) on both the length side and the width side, and the center of the cutout (7) on the length side is located on the center line of the longitudinal isolation zone, and the center of the cutout (7) on the width side is located on the center line of the transverse isolation zone, and the shapes of the cutouts (7) on the length side and the width side are different.

11. The ultra-narrow semiconductor lead frame according to claim 10, characterized in that: The shape of the cutout (7) on one length edge of the conductive substrate (2) is V-shaped, and the port edges on both sides of the V-shape are provided with C chamfers.

12. The ultra-narrow semiconductor lead frame according to claim 11, characterized in that: The shape of the cutout (7) on the other length side of the conductive substrate (2) is a trapezoid.

13. The ultra-narrow semiconductor lead frame according to claim 10, characterized in that: The cutout (7) on the width side of the conductive substrate (2) is semicircular.

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