Spring Bar Lead Frame

Abstract

The method (200) includes attaching semiconductor dies to die attach pads of first and second columns of a lead frame (204); encapsulating the semiconductor dies of each column in respective first and second packaged structures (208); trimming the lead frame (210) to separate respective first and second lead portions of adjacent ones of the first and second columns of the lead frame; moving the first column relative to the second column along a column direction (214); and separating (216) the individual packaged electronic devices of each of the first and second columns from one another.

Description

[Technical Field]

[0001] The cost of electronic device manufacturing can be reduced by increasing the number of devices on a given leadframe panel (also referred to as a leadframe sheet or strip). Columns of devices on a leadframe sheet can be interdigitated to increase device density, but the interdigitated devices require trim and form dies to singulate or separate the individual packaged devices from the leadframe. Trim and form dies are also used in electronic device manufacturing to cut and form the leads of individual devices, while some leadframe strips comprise rows and columns of partially completed devices. However, when manufacturing a variety of different devices with different lead counts and configurations, multiple trim and form die sets are required for the different leadframe strip configurations. Summary of the Invention

[0002] According to one aspect, a leadframe is provided. The leadframe includes a metal structure having potential device portions arranged in rows and columns along respective first and second directions. The columns include first and second columns, with at least some of the first columns adjacent to one of the second columns. The leadframe includes a punch structure having a punch bar extending along the second direction from a first end of each first column to a first clamp portion of the metal structure. The leadframe also includes an extension structure having a spring bar extending from a second end of each first column to a second clamp portion of the metal structure.

[0003] In one example, the spring bars extend along an arcuate path. In one example, each punch structure includes a second punch bar extending along a second direction from a first end of the respective first column to a first clamp portion of the metal structure, and each extension structure includes a second spring bar extending along a second arcuate path from a second end of the respective first column to a second clamp portion of the metal structure. In one example, each spring bar and second spring bar include first and second arcuate portions.

[0004] In one implementation, the punch bar is deformable along a third direction perpendicular to the plane of the first and second directions, and the spring bar is configured to extend along the second direction to enable movement of each first column along the second direction toward the first clamp portion of the metal structure.

[0005] In one example, the first column has first device portions including respective first die attach pads and respective first lead portions, and the second column has second device portions including respective second die attach pads and respective second lead portions. In one implementation, at least some of the first lead portions of a given one of the first columns are connected to respective ones of the second lead portions of second device portions of adjacent one of the second columns. In one example, the first columns and the second columns alternate. In one example, the spring bar is configured to extend along the second direction toward the first clamp portion a pitch spacing distance of the first lead portions in response to deformation of the punch bar by the punch depth dimension.

[0006] According to another aspect, a method is provided that includes attaching a first semiconductor die to a respective first die attach pad of a respective first device portion of a respective first column of a leadframe and attaching a second semiconductor die to a respective second die attach pad of a respective second device portion of a respective second column of the leadframe. The method further includes performing a molding process and separating the individual packaged electronic devices of the respective first and second columns from one another. The molding process encapsulates the first semiconductor die of each respective first column within a respective single first package structure and the second semiconductor die of each respective second column within a respective single second package structure.

[0007] In one example, the lead frame includes rows extending along a first direction and first and second columns extending along a perpendicular second direction, and the method further includes cutting the lead frame and the first and second package structures along cutting lines between first device portions in each first column and second device portions in each second column, the cutting lines being parallel to the first direction.

[0008] In one example, moving the first columns along the second direction includes deforming a punch bar proximate a first end of each first column along a third direction perpendicular to the plane of the first and second directions to extend a spring bar proximate a second end of each first column along the second direction. In one implementation, moving the first columns along the second direction includes moving the first columns relative to the second columns by a pitch distance of the first lead portions.

[0009] In one example, before performing the molding process, the method further includes performing an electrical connection process, where the electrical connection process electrically couples at least one of the first lead portions to a conductive feature of a respective first semiconductor die and electrically couples at least one of the second lead portions to a conductive feature of a respective second semiconductor die.

[0010] In one example, before separating the individual packaged electronic devices from one another, the method further includes performing a lead trimming process to cut the lead frame along a trim line to separate respective first and second lead portions of adjacent ones of the first and second columns of the lead frame, and moving the first column along a second direction relative to the second column, the trim line being parallel to the second direction.

[0011] According to another aspect, an electronic device is provided. The electronic device includes a molded package structure. The molded package structure has a first side, a second side spaced from the first side along a first direction, a first end, a second end spaced from the first end along a second direction, a top, and a bottom spaced from the top along a third direction. The second direction is perpendicular to the first direction, and the third direction is perpendicular to a plane of the first and second directions. The electronic device also includes a semiconductor die surrounded by the molded package structure, first conductive leads along the first side, at least one of the first conductive leads electrically coupled to the semiconductor die, and second conductive leads along the second side. At least one of the second conductive leads is electrically coupled to the semiconductor die, and the respective first and second ends are planar.

[0012] In one example, each of the first and second sides includes a first portion extending from the top to the mold parting line at a first angle relative to the plane of the second and third directions, and a second portion extending from the bottom to the mold parting line at a second angle relative to the plane of the second and third directions. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a partial top view of a lead frame with interdigitated columns and punch and extension structures at each end of the odd-numbered columns according to one embodiment.

[0014] [Figure 2] 10 is a flowchart of a method according to another embodiment.

[0015] [Figure 3] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 4] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 5] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 6] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 7] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 8] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 9] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 10] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 11] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 12] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 13] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 14] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 15] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device. [Figure 16] 2 illustrates the lead frame of FIG. 1 in a manufacturing process to produce a packaged electronic device.

[0016] [Figure 17] FIG. 1 is a perspective view of a packaged electronic device according to another embodiment.

[0017] [Figure 18] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns. [Figure 19] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns.

[0018] [Figure 20] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns. [Figure 21] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns.

[0019] [Figure 22] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns. [Figure 23]FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns.

[0020] [Figure 24] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns. [Figure 25] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns.

[0021] [Figure 26] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns. [Figure 27] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns.

[0022] [Figure 28] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns. [Figure 29] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns.

[0023] [Figure 30] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns. [Figure 31] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns.

[0024] [Figure 32]FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns. [Figure 33] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns.

[0025] [Figure 34] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns. [Figure 35] FIG. 1 is a partial top view of a lead frame with interdigitated columns, showing another example of an extension structure at the bottom end of the odd-numbered columns. DETAILED DESCRIPTION OF THE INVENTION

[0026] In the drawings, like reference numerals refer to like elements throughout, and various features are not necessarily drawn to scale. Also, the term "couple" includes an indirect or direct electrical or mechanical connection, or a combination thereof. For example, when a first device couples to or is coupled to a second device, the connection may be through a direct electrical connection, or through an indirect electrical connection via one or more intervening devices and connections. One or more operating characteristics of various circuits, systems, and / or components are described below, in some cases, in the context of the function that results from the configuration and / or interconnection of the various structures when the circuit elements are powered and operated.

[0027] 1 shows a partial top view of a leadframe 100 formed as a panel or strip with first and second interdigitated columns 101 and 102, respectively. Leadframe 100 includes a metal structure, such as copper, with device portions expected to be arranged in rows along a first direction (e.g., the X direction in FIG. 1 ) and in columns along a second direction (e.g., the Y direction in FIG. 1 ), the first and second directions being perpendicular to each other. The leadframe is in an interdigitated arrangement such that device portions in each of first column 101 are offset or shifted along the second direction relative to device portions in second column 102.

[0028] According to one embodiment, leadframe 100 has punch and extension structures at each end of first column 101. These features facilitate trimming the device leads of the interdigitated columns using sawing or other cutting operations, followed by molding and sawing into separate packaged devices, without the need for a lead trim die for lead trimming. The punch and extension structures facilitate moving first column 101 along the column direction after lead trimming and molding to align the previously offset lead portions of first and second columns 101 and 102. Leadframe 100 is in an interdigitated configuration with device portions in each column 101 and 102 including respective die attach pads and lead portions having a pitch spacing distance 103. The device portions and respective lead portions in first and second columns 101 and 102 are offset or shifted relative to one another by a single pitch spacing distance 103. In other examples, the offset is an integer multiple of pitch spacing distance 103, where the integer is 2 or greater. In other instances, the interdigitated column offset is not an integer multiple of the pitch spacing distance 103. Leadframe 100 also includes several fixture alignment holes 106 to facilitate X,Y positioning of leadframe 100 in a fixture or jig (not shown).

[0029] Each first column 101 has a first end 111 and a second end 112 spaced apart from the first end 111 along the second direction. Each first column 101 also includes a punch structure 114 having a punch bar 115 extending along the second direction from the first end 111 of the respective first column 101 to a first clamp portion 113 of the metal structure. The punch bar 115 is deformable along a third direction Z perpendicular to the plane of the respective first and second directions X and Y (e.g., deformable into or out of the plane of the page in FIG. 1 ). The illustrated punch structure 114 includes a second punch bar 115 extending along the second direction Y from the first end 111 of the respective first column 101 to the first clamp portion 113 of the metal structure. Other examples include an integer number of one or more punch bars 115.

[0030] Each first column 101 also includes an extension structure 116 having a spring bar 117. Each first column 101 has a first device portion, each first device portion including a respective first die attach pad 118 and a respective first lead portion 119. The spring bar 117 extends along an arcuate path from the second end 112 of each first column 101 to the second clamp portion 120 of the metal structure. The spring bar 117 is configured to extend along a second direction Y to enable movement of each first column 101 along the second direction Y toward the first clamp portion 113 of the metal structure. As described further below in connection with FIGS. 11-14 , the spring bar 117 in the example of FIG. 1 is configured to extend along the second direction Y toward the first clamp portion 113 by the pitch spacing distance 103 of the first lead portions 119 in response to deformation of the punch bar 115 by the punch depth dimension. The illustrated extension structure 116 includes a second spring bar 117 that extends along a second arcuate path from the second end 112 of each first column 101 to the second clamp portion 120 of the metal structure. Other examples include an integer number of one or more spring bars 117. In some examples, each spring bar 117 and second spring bar 117 includes first and second arcuate portions. In other examples, the spring bar 117 includes an integer number of one or more arcuate portions.

[0031] Each second column 102 has a first end 121 and a second end 122 spaced from each first end 121 along the second direction. Each second column 102 has a second device portion including a respective second die attach pad 128 and a respective second lead portion 129. The leadframe 100 of FIG. 1 has alternating first columns 101 and second columns 102, with at least some of the first columns 101 adjacent to one of the second columns 102. In other examples, two or more second columns 102 can be adjacent to each other, with each first column 101 adjacent to at least one of the second columns 102. In the example of FIG. 1, prior to lead trimming, at least a portion of the first lead portion 119 of a given one of the first columns 101 is connected to a respective one of the second lead portions 129 of a second device portion of an adjacent second column of the second columns 102.

[0032] 2-17, FIG. 2 illustrates a method 200 for manufacturing a packaged electronic device, FIGS. 3-16 illustrate the leadframe 100 of FIG. 1 undergoing processing according to method 200, and FIG. 17 illustrates a packaged electronic device according to another embodiment. Method 200 includes providing or creating a leadframe (e.g., leadframe 100) at 210, attaching semiconductor dies to die attach pads in first and second columns of the leadframe at 204, and encapsulating the semiconductor dies in columns 101 and 102 into respective first and second package structures at 208. Method 200 also includes trimming leadframe 100 at 210 to separate first and second lead portions (e.g., 119 and 129) of adjacent ones of first and second columns 101 and 102, respectively. The method 200 also includes forming leads at 212, moving the first column relative to the second column along a column direction at 214, and performing package separation at 216 to separate the individual packaged electronic devices in each of the first and second columns from each other and from the lead frame 100.

[0033] In one example, at 202, a starting leadframe 100 is provided or fabricated as a metal structure formed as interdigitated strips having rows and respective first and second columns 101 and 102, and respective punch and extension structures 114 and 116, as shown in FIG. 1 above.

[0034] Method 200 includes performing a die attach process at 204. FIG. 3 shows an example in which die attach process 300 is performed to attach a first semiconductor die 301 to each first die attach pad 118 of a first device in each first column 101 of leadframe 100. In this example, first semiconductor die 301 includes a conductive feature, such as a copper bond pad 311, on its top or upper side. Furthermore, die attach process 300 attaches a second semiconductor die 302 to each second die attach pad 128 of a second device portion in each second column 102 of leadframe 100. Second semiconductor die 302 in FIG. 3 includes a conductive feature 312 on its top side. One or both of semiconductor dies 301 or 302 may include conductive features, such as solder bumps, copper pillars, etc. (not shown), that are electrically coupled to the respective die attach pads 118 and 128 using, for example, flip-chip die attach process 300. In another example, die 301 and / or 302 are epoxied to their respective die attach pads at 204 .

[0035] Method 200 continues at 206 with wire bonding or other electrical connection processing. FIG. 4 shows an example in which an electrical connection process 400 is performed, including wire bonding that electrically couples one or more of the first lead portions 119 to respective conductive features 311 of the first semiconductor die 301 in the first column 101. Process 400 also electrically couples one or more of the second lead portions 129 to respective conductive features 312 of the second semiconductor die 302 in the second column 102. In one example, electrical connection process 400 is performed while leads 119, 129 are connected to each other as shown in FIG. 4. Wire bonding process 400 connects first bond wires 401 between each of the first lead portions 119 in the first column 101 and respective conductive features 311 of the first semiconductor die 301. The example wire bonding process 400 also connects second bond wires 402 between each of the second lead portions 129 in the second column 102 and respective conductive features 312 of the second semiconductor die 302 .

[0036] Method 200 continues at 208 with a molding process that creates a single molded package structure along each of the first and second columns 101 and 102. FIGS. 5 and 6 show an example in which molding process 500 is performed to encapsulate first semiconductor die 301 of each respective first column 101 within a single respective first package structure 501. Molding process 500 also encapsulates second semiconductor die 302 of each respective second column 102 within a single respective second package structure 502. Process 500 uses a mold (not shown) with a single mold cavity having an upper and lower portion that create tapered sides that meet at a mold parting line having an upper first draft angle θ1 and a lower second draft angle θ2, as shown in FIG. 5 for each individual column 101 and 102. In one example, the cavities associated with the first column 101 are offset along the second direction (Y) by the lead pitch dimension from the cavities associated with the second column 102 to create offset molded package structures 501 and 502 as shown in FIG. 6, although this is not a strict requirement for all possible implementations.

[0037] Method 200 continues at 210 with column-wise lead trimming to separate leads in adjacent columns. FIGS. 7 and 8 show an example in which a lead trimming process 700 is performed using a saw to cut leadframe 100 along trim lines 701 between adjacent pairs of first and second columns 101 and 102. Process 700 separates the respective first and second lead portions 119 and 129 of adjacent ones of first and second columns 101 and 102 that were previously joined within starting leadframe 100 of FIG. 1 . In one example, process 700 uses multiple cutting saw blades that simultaneously cut along each trim line 701. In another example, a single cutting blade is used to sequentially cut designated portions of leadframe 100 along line 701. In another example, a laser is used to cut designated portions of leadframe 100 along trim line 701. In the illustrated example, the trim lines 701 are parallel to each other and to the second direction, although this is not a requirement for all possible implementations.

[0038] The method 200 continues with lead formation at 212. Figures 9 and 10 show an example in which a lead formation process 900 is performed to form the first and second lead portions 119 and 129 of the respective first and second columns 101 and 102 into a gull-wing shape. In other examples, the first and second lead portions 119 and 129 are formed into a different shape, such as a J-lead.

[0039] The method 200 continues at 214 by translating or moving the first column 101 along a second direction relative to the second column 102. Figures 11-14 illustrate an example in which the lead frame 100 is positioned (Figures 11 and 12) and the first and second clamping portions 113 and 120 are clamped by a clamping device or other fixture feature, with the punch being moved (Figures 13 and 14) along a third direction (e.g., the Z direction in Figures 11 and 13) to deform the punch bar 115. Figure 11 shows a cross-sectional view of a portion of the lead frame 100 proximate a first end 111 of one of the first columns 101, taken along line 11-11 in Figure 12. A first clamp 1101 engages the top side of the upper end of the leadframe 100, as shown in FIGS. 11 and 12, and a lower clamp 1102 engages the underside of the leadframe 100 to hold the end of the leadframe 100 stationary, as shown in FIG. 11. A lower die 1104 (FIG. 11) engages the bottom of a section of the punch bar 115, leaving a gap between the lower die 1104 and the lower die 1102. A punch 1106 is positioned above the top side of the punch bar 115 in FIG. 11, in a position above the gap between the lower die 1104 and the lower clamp 1102. As further shown in FIG. 12, a second clamp 1202 engages the top side of the bottom end of the leadframe 100. As shown in FIG. 12, similar clamp and punch die features are provided at the end of each individual first column 101.

[0040] 13 and 14 illustrate an example in which a punch process 1300 is performed in which a punch 1106 is moved downward (e.g., along a third direction “Z” in FIG. 13 ) perpendicular to the XY plane in the respective first and second directions to deform a punch bar 115 proximate the first end 111 of each first column 101. The Z-direction deformation of the punch bar 115 through the punch depth dimension PD ( FIG. 13 ) moves the first column 101 along the second direction relative to the second column 102 by the pitch spacing distance 103 of the first lead portions 119 (e.g., upward along the direction of the arrow in FIG. 14 ).

[0041] Movement of the first column 101 along the second direction extends the spring bar 117 of the first column 101 along the second direction, as shown in FIG. 14 . In one example, the punch 1106 is translated along the Z direction by an automated servo system (not shown). In another example, the punch 1106 is manually actuated. In one example, the punch depth dimension PD and the resulting Z movement of the punch 1106 are adjusted according to the pitch spacing distance 103 or any other desired amount of Y movement of the first column 101 relative to the second column 102, as well as according to the thickness and material of the leadframe 100.

[0042] The method 200 continues at 216 with a row-wise cut to separate the individual packaged electronic devices. The cut at 216 also creates a molded package and has a zero draft angle. FIGS. 15 and 16 show an example of performing a sawing process 1500 along cut line 1501 to separate the individual device portions of the column-length mold structure and form first and second ends 1502 and 1503, respectively, for the individual packaged electronic devices 1511 and 1512 in each of the first and second columns 101 and 102. The sawing process 1500 separates the individual packaged electronic devices 1511, 1512 in each of the first and second columns 101 and 102 from each other. In another example, the packaged electronic devices 1511 and 1512 are separated from each other and from the leadframe 100 using another cutting technique, such as laser cutting. Because columns 101 and 102 are pre-aligned by the punching operation at 214, cut lines 1501 extend between the first device portions of each first column 101 and between the second device portions of each second column 102. In this example, cut lines 1501 are parallel to the first direction, although this is not a requirement for all possible implementations.

[0043] Method 200, including punch structure 114 and extension structure 116, facilitates improved leadframe strip device density through an interdigitated starting leadframe configuration (e.g., leadframe 100) while enabling sawing operations for lead trimming and device separation without requiring multiple trim and form die sets to accommodate multiple lead counts and package sizes during integrated circuit fabrication. Package sawing at 216 can be easily adapted to different leadframe configurations by modifying the saw equipment recipe or program, without requiring multiple tool sets (e.g., punch die sets) to accommodate multiple lead counts. In one example, a fixture (not shown) is used for manual pressing of punch 1106, including a handle, hinged punch stop, track, and fixture base (not shown), such that Y-direction translation of first column 101 provides accurate and repeatable pitch correction according to punch depth PD. As shown in Figures 13 and 14, the spring bar 117 in the example of Figure 1 is configured to extend along the second direction toward the first clamp portion 113 by the pitch spacing distance 103 of the first lead portion 119 in response to deformation of the punch bar 115 by the punch depth dimension PD.

[0044] 17 shows a perspective view of an exemplary packaged electronic device 1511 (e.g., an integrated circuit or IC) manufactured by the method 200 of FIG. 2 using the starting leadframe 100 of FIG. 1. The electronic device 1511 includes a molded package structure 501 having a first side 1701, an opposing second side 1702 spaced from the first side 1701 along a first direction (X), a first end 1502, and a second end 1503 spaced from the first end 1502 along a second direction (Y). The electronic device 1511 also includes a top 1706 and a bottom 1708 spaced from the top 1706 along a third direction (Z). The electronic device 1511 in this example includes a semiconductor die 301 surrounded by a molded package structure 501 (e.g., FIG. 4 above), first conductive leads 119 along a first side 1701 of the package structure 501, and second conductive leads 119 along a second side 1702. The leads 119 have a pitch spacing 103 as described above. In one example, one or more of the first conductive leads 119 are electrically coupled to the semiconductor die 301, and one or more of the second conductive leads 119 are electrically coupled to the semiconductor die 301 (e.g., via bond wires 401 shown in FIG. 4).

[0045] The sawing process used to separate the packaged electronic devices 1511 and 1512 forms flat first and second ends 1502 and 1503, as shown in FIG. 17. In one example, each of the first and second sides 1701 and 1702 includes a first portion 1711 extending from the top 1706 to the mold parting line 1704 at a first non-zero angle Θ relative to the YZ plane in the second and third directions. Each of the first and second sides 1701 and 1702 also includes a second portion 1712 extending from the bottom 1708 to the mold parting line 1704 at a second non-zero angle Θ relative to the YZ plane. In one example, the first and second angles are equal (e.g., Θ = Θ), although this is not a strict requirement for all possible implementations.

[0046] The tension structure 116 and associated spring bar 117 at the second end 112 of the first column 101 in FIG. 1 provide a single yield point design that is good for manufacturability. FIGS. 1 and 10 show the spring bar 117 before punch actuation, and FIG. 14 shows the tension spring bar 117 moved 0.409 inches in response to punch actuation to a punch depth PD of 0.032 inches (FIG. 13). In certain examples, the spring bar 117 has a single arcuate portion. In other examples, the spring bar 117 has multiple arcuate portions. Different implementations have one or more yield points for each spring bar 117.

[0047] 18-35 show different example implementations of spring bars and extension structures proximate second end 112 of first column 101. These examples include lead portions 119 and 129, alignment holes 106, molded package structures 501 and 502, and lower clamp 1202, as previously described.

[0048] Figures 18 and 19 show partial top views of a leadframe 1800 with interdigitated columns as described above. Figures 18 and 19 show another embodiment of an extension structure 1816 and associated spring bar 1817 at the second end 112 of the odd-numbered columns. Figure 18 shows the leadframe 1800 in the interdigitated configuration before extension, and Figure 19 shows the leadframe 1800 after the first column has been moved upward along the second (e.g., Y) direction. In this example, the punch depth PD is 0.025 inches and the second directional movement is 0.397 inches.

[0049] 20 and 21 show partial top views of a leadframe 2000 with interdigitated columns as described above. FIGS. 20 and 21 show another embodiment of an extension structure 2016 and associated spring bar 2017 at the second end 112 of the odd-numbered columns. FIG. 20 shows the leadframe 2000 in its interdigitated configuration before extension, while FIG. 21 shows the leadframe 2000 after the first column has been moved upward along the second (e.g., Y) direction. In this example, the punch depth PD is 0.022 inches and the second direction movement is 0.431 inches.

[0050] Figures 22 and 23 show partial top views of a leadframe 2200 with interdigitated columns as described above. Figures 22 and 23 show another embodiment of an extension structure 2216 and associated spring bar 2217 at the second end 112 of the odd-numbered columns. Figure 22 shows the leadframe 2200 before extension, and Figure 23 shows the leadframe 2200 after the first column has been moved upward along the second direction, with a punch depth PD of 0.020 inches and a second direction movement of 0.412 inches.

[0051] Figures 24 and 25 show partial top views of a leadframe 2400 with interdigitated columns as described above. Figures 24 and 25 show another embodiment of an extension structure 2416 and associated spring bar 2417 at the second end 112 of the odd-numbered columns. Figure 24 shows the leadframe 2400 before extension, and Figure 25 shows the leadframe 2400 after the first column has been moved upward with a punch depth PD of 0.020 inches and a second directional movement of 0.047 inches.

[0052] Figures 26 and 27 show partial top views of a leadframe 2600 with interdigitated columns as described above. Figures 26 and 27 show another embodiment of an extension structure 2616 and associated spring bar 2617 at the second end 112 of the odd-numbered columns. Figure 26 shows the leadframe 2600 before extension, and Figure 27 shows the leadframe 2600 after the first column has been moved upward with a punch depth PD of 0.118 inches and a second directional movement of 0.046 inches.

[0053] Figures 28 and 29 show partial top views of a leadframe 2800 with interdigitated columns as described above. Figures 28 and 29 show another embodiment of an extension structure 2816 and associated spring bar 2817 at the second end 112 of the odd-numbered columns. Figure 28 shows the leadframe 2800 before extension, and Figure 29 shows the leadframe 2800 after the first column has been moved upward with a punch depth PD of 0.023 inches and a second directional movement of 0.400 inches.

[0054] Figures 30 and 31 show partial top views of a leadframe 3000 with interdigitated columns as described above. Figures 30 and 31 show another embodiment of an extension structure 3016 and associated spring bar 3017 at the second end 112 of the odd-numbered columns. Figure 30 shows the leadframe 3000 before extension, and Figure 31 shows the leadframe 3000 after the first column has been moved upward with a punch depth PD of 0.023 inches and a second directional movement of 0.454 inches.

[0055] Figures 32 and 33 show partial top views of a leadframe 3200 with interdigitated columns as described above. Figures 32 and 33 show another embodiment of an extension structure 3216 and associated spring bar 3217 at the second end 112 of the odd-numbered columns. Figure 32 shows the leadframe 3200 before extension, and Figure 33 shows the leadframe 3200 after the first column has been moved upward with a punch depth PD of 0.042 inches and a second directional movement of 0.011 inches.

[0056] Figures 34 and 35 show partial top views of a leadframe 3400 with interdigitated columns as described above. Figures 34 and 35 show another embodiment of an extension structure 3416 and associated spring bar 3417 at the second end 112 of the odd-numbered columns. Figure 34 shows the leadframe 3400 before extension, and Figure 35 shows the leadframe 3500 after the first column has been moved upward with a punch depth PD of 0.036 inches and a second directional movement of 0.421 inches.

[0057] The designs of Figures 1, 22-23, 32-33 and 28-29 provide pitch correction results comparable to the spring bar 1817 of Figures 18 and 19. The designs of Figures 20-21, 24-25, 26-27, 30-31 and 34-35 provide higher values ​​of pitch correction along the second direction.

[0058] The foregoing examples are merely illustrative of some of the possible implementations of various aspects of the present disclosure, and equivalent variations and / or modifications may occur to others skilled in the art upon reading and understanding this specification and the accompanying drawings. Modifications may be made to the exemplary implementations described, and other embodiments are possible, within the scope of the claims of the present invention.

Claims

1. A lead frame, 1. A metal structure having device portions likely to be arranged in rows extending along a first direction and columns extending along a second direction perpendicular to the first direction, the columns comprising: a first column having a respective first end and a second end spaced from the respective first end along the second direction, and a first device portion including a respective first die attach pad and a respective first lead portion; second columns having second device portions including respective second die attach pads and respective second lead portions, at least some of the first columns being adjacent to one of the second columns; the metal structure comprising: a punch structure including a first flat punch bar extending along the second direction from a first end of each of the first columns to a first clamp portion of the metal structure, the first flat punch bar being deformable along a third direction perpendicular to the plane of the first and second directions; an extension structure including a first spring bar extending along an arcuate path from a second end of each first column to a second clamping portion of the metal structure, the first spring bar configured to extend along the second direction to enable movement of each first column along the second direction toward the first clamping portion of the metal structure; 2. A lead frame comprising:

2. 10. The lead frame of claim 1, A lead frame in which at least some of the first lead portions of a given first column of said first columns are connected to respective ones of the second lead portions of second device portions of an adjacent second column of said second columns.

3. 3. The lead frame of claim 2, The lead frame is further configured such that the first spring bar extends toward the first clamp portion along the second direction by a pitch spacing distance of the first lead portions in response to deformation of the first flat punch bar by a punch depth dimension.

4. 10. The lead frame of claim 1, The lead frame is further configured such that the first spring bar extends toward the first clamp portion along the second direction by a pitch spacing distance of the first lead portions in response to deformation of the first flat punch bar by a punch depth dimension.

5. 10. The lead frame of claim 1, The lead frame, wherein the first columns and the second columns are alternately arranged.

6. 10. The lead frame of claim 1, the punch structure further includes a second flat punch bar extending along the second direction from a first end of each of the first columns to a first clamp portion of the metal structure; the extension structure further includes a second spring bar extending along a second arcuate path from a second end of each first column to a second clamping portion of the metal structure.

7. 7. The lead frame of claim 6, The lead frame, wherein the first spring bar and the second spring bar include first and second arcuate portions.

8. 10. The lead frame of claim 1, The lead frame wherein the first spring bar includes first and second arcuate portions.

9. 1. A method comprising: providing a lead frame including rows extending along a first direction and first and second columns extending along a second direction perpendicular to the first direction; attaching a first semiconductor die to a first die attach pad on each of a first device portion of a first column of the leadframe; attaching a second semiconductor die to a second die attach pad on each of a second device portion of a second column of the leadframe; encapsulating the first semiconductor dies of the first column within respective single first package structures; encapsulating the second semiconductor dies of the second column within a single respective second package structure; cutting the lead frame along trim lines to separate first and second lead portions of adjacent first and second columns of the lead frame, the trim lines being parallel to the second direction; clamping both ends of a first column of the lead frame; moving the first column relative to the second column in the second direction; cutting the leadframe and the first and second package structures along cutting lines between first device portions in the first column and second device portions in the second column; A method comprising:

10. 10. The method of claim 9, moving the first column along the second direction relative to the second column; deforming a punch bar proximate a first end of the first column along a third direction perpendicular to the plane of the first and second directions to extend a spring bar proximate a second end of the first column along the second direction; A method comprising:

11. 10. The method of claim 9, moving the first column along the second direction relative to the second column; moving the first column relative to the second column by a pitch spacing distance of the first lead portion; A method comprising:

12. 10. The method of claim 9, electrically coupling at least one of the first lead portions to a conductive feature of a respective first semiconductor die of each first device portion of the first column prior to the encapsulating; electrically coupling at least one of the second lead portions to a conductive feature of a second semiconductor die of each second device portion of the second column; The method further comprises:

13. 1. A method comprising: providing a lead frame including rows extending along a first direction and first and second columns extending along a second direction perpendicular to the first direction; attaching a first semiconductor die to a first die attach pad on each of a first device portion of a first column of the leadframe; attaching a second semiconductor die to a second die attach pad on each of a second device portion of a second column of the leadframe; encapsulating the first semiconductor dies of the first column within a single respective first package structure; encapsulating the second semiconductor dies of the second column within a single respective second package structure; cutting the lead frame along a trim line to separate first and second lead portions of adjacent first and second columns of the lead frame; clamping both ends of a first column of the lead frame; moving the first column relative to the second column in the second direction; separating the individual packaged electronic devices in the first and second columns of the lead frame from one another; A method comprising:

14. 14. The method of claim 13, moving the first column in the second direction relative to the second column; deforming a punch bar proximate a first end of the first column along a third direction perpendicular to the plane of the first and second directions to extend a spring bar proximate a second end of the first column along the second direction; A method comprising:

15. 14. The method of claim 13, moving the first column relative to the second column along the second direction; moving the first column relative to the second column by a pitch spacing distance of the first lead portion; A method comprising:

16. 14. The method of claim 13, electrically coupling at least one of the first lead portions to a conductive feature of a respective first semiconductor die of each first device portion of the first column prior to the encapsulating; electrically coupling at least one of the second lead portions to a conductive feature of a second semiconductor die of each second device portion of the second column; The method further comprises:

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