Leadframe strip with molded bus and method of manufacturing semiconductor package

Abstract

This application provides a leadframe strip with a molding bus and a method for manufacturing a semiconductor package. The leadframe strip includes multiple blocks. Each block includes a molding bus, a first plurality of rows, a first plurality of molding gates, a second plurality of rows, and a second plurality of molding gates. The first plurality of rows are located on a first side of the molding bus, and the second plurality of rows are located on a second side of the molding bus, with the second side opposite to the first side. The manufacturing method includes the following steps: providing the leadframe strip; mounting multiple transistors; connecting multiple metal clips or multiple bonding wires; forming a molded package; performing a stamping process; and performing a sawing process. The process time is shorter, the lead wettability is better, and the package is easier to pick up during assembly; the semiconductor package structure is compact and the size is flexible.

Description

Technical Field

[0001] The present invention generally relates to a lead frame strip and a method of using the same, and more specifically, to a lead frame strip for laying molded busbars between lead frame blocks. Background Technology

[0002] U.S. Patent No. 7,943,424 by Wang et al., U.S. Patent Application Publication No. 2011 / 0129962 by Wang et al., and U.S. Patent Application Publication No. 2015 / 0325503 by Lim et al. disclose a manufacturing method of stamping followed by sawing.

[0003] In semiconductor packaging technology, to improve production efficiency and reduce costs, multiple semiconductor chips are typically assembled and packaged simultaneously on a continuous lead frame to form a matrix array, and then individual packaging units are separated from the array. Currently, there are two main separation processes: stamping and a hybrid process combining stamping and sawing.

[0004] The pure stamping process directly severs the connecting ribs between adjacent package units using a die. While this method is fast, to avoid damage to the package during stamping, a gap of more than 1 mm must be maintained between adjacent package units. This excessively large gap leads to low material utilization of the lead frame, increasing the manufacturing cost of a single package.

[0005] To address the aforementioned issues, existing technologies have proposed a hybrid process. For example, the solution disclosed in US Patent Publication No. US2011 / 0129962A1 first involves stamping and cutting the transverse binding strips connecting different packaging strips, thus electrically isolating the packaging strips from each other. Subsequently, a sawing process is used to divide the packaging strips into individual packaging units along their length. This approach avoids the burr and delamination problems associated with sawing metal leads, while allowing for narrower cuts between packaging units, thus improving the material utilization of the lead frame.

[0006] However, the lead frame structure used in the aforementioned hybrid process still follows the traditional unidirectional strip layout, meaning that the packaging units are arranged in a strip in only one direction. In the molding process, this structure typically only allows for the molding of one or a few rows of packaging units per molding cycle, limiting further improvements in production efficiency.

[0007] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art. Summary of the Invention

[0008] To achieve the above objectives, the present invention provides a lead frame strip, comprising: Multiple blocks, each block includes: A molded bus extending along a first direction; A first plurality of rows extending along a second direction perpendicular to the first direction, the first plurality of rows being located on a first side of the molding bus; The first plurality of molding gates are connected to the first plurality of rows of molding bus; A second plurality of rows extending along the second direction, the second plurality of rows being located on a second side of the molding bus opposite to the first side; The second plurality of molding gates are connected to the second plurality of rows; Each of the first plurality of rows and the second plurality of rows includes: Multiple lead frames, each lead frame comprising: A chip pad; A plurality of leads extending along the first direction; and A plurality of connecting ribs that are connected to the chip pads and extend along the second direction.

[0009] In some embodiments, the first plurality of rows and the second plurality of rows are symmetrical about the molding bus.

[0010] In some embodiments, a plurality of saw marks extending along the first direction are also included.

[0011] In some embodiments, a plurality of stamping marks extending along the second direction are also included.

[0012] In some embodiments, the plurality of leads include: One or more top leads connected to the chip pads; and One or more bottom leads separated from the chip pads; The one or more upper leads and the one or more lower leads are symmetrical about the center of the chip pads.

[0013] In some embodiments, the plurality of connecting ribs includes: A first connecting bar; and A second connecting bar; The first connecting rib and the second connecting rib are symmetrical about the center of the chip pad.

[0014] This application also provides a method for manufacturing a semiconductor package, the method comprising the following steps: A lead frame strip is provided, the lead frame strip comprising: Multiple blocks, each block includes: A molded bus extending along a first direction; A first plurality of rows extending along a second direction perpendicular to the first direction, the first plurality of rows being located on a first side of the molding bus; The first plurality of molding gates are connected to the first plurality of rows of molding bus; A second plurality of rows extending along the second direction, the second plurality of rows being located on a second side of the molding bus opposite to the first side; and The second plurality of molding gates are connected to the second plurality of rows; Each of the first plurality of rows and the second plurality of rows includes: Multiple lead frames, each lead frame comprising: A chip pad; A plurality of leads extending along the first direction; and A plurality of connecting ribs connected to the chip pads and extending along the second direction; Install multiple transistors; Connecting multiple metal clips or multiple bonding wires; A molded package is formed, the molded package encapsulating the plurality of transistors and the plurality of metal clips or the plurality of bonding wires; Perform the stamping process; A sawing process is performed to separate the semiconductor package from the adjacent semiconductor package.

[0015] In some embodiments, the first plurality of rows and the second plurality of rows are symmetrical about the molding bus.

[0016] In some embodiments, a plurality of saw marks extending along the first direction are also included.

[0017] In some embodiments, a plurality of stamping marks extending along the second direction are also included.

[0018] In some embodiments, the plurality of leads include: One or more top leads connected to the chip pads; and One or more bottom leads separated from the chip pads; The one or more upper leads and the one or more lower leads are symmetrical about the center of the chip pads.

[0019] In some embodiments, the plurality of connecting ribs includes: A first connecting bar; and A second connecting bar; The first connecting rib and the second connecting rib are symmetrical about the center of the chip pad.

[0020] In some embodiments, the top of the semiconductor package includes: A first straight edge extending along the first direction; A second straight edge extending along the first direction and opposite to the first straight edge; A first rounded edge extending along the second direction; and A second rounded edge that extends along the second direction and is opposite to the first rounded edge.

[0021] In some embodiments, the cuboid portion of each of the plurality of leads is exposed from the molded package.

[0022] In some embodiments, the molded package encapsulates a shortened portion of each of the plurality of connecting ribs, with only the sawn facet of each of the plurality of connecting ribs exposed from the molded package.

[0023] In some embodiments, during the stamping process, a portion of each of the plurality of leads is removed.

[0024] In some embodiments, each lead frame includes a plurality of metal segments located between the plurality of leads; and In the step of performing the stamping process, a portion of the plurality of metal segments and each of the plurality of leads is removed.

[0025] In summary, compared with existing technologies, this invention proposes a lead frame strip for laying molded buses between lead frame blocks. The manufacturing process is as follows: first, a molding encapsulation process is performed, followed by a stamping process, and finally a sawing process. The advantages of the stamping process include shorter processing time, better lead wettability, and easier pickup of the package during assembly. The advantages of the sawing process include a compact semiconductor package structure (higher lead frame density in the lead frame strip, saving space), flexible semiconductor package size, and no protruding connecting ribs in the molded encapsulation portion of the semiconductor package. Attached Figure Description

[0026] Figure 1 This is a front view of the lead frame strip in an embodiment of the present invention.

[0027] Figure 2 This is a flowchart of the semiconductor packaging manufacturing process in an embodiment of the present invention.

[0028] Figure 3A , 3B 3D, 3EA, 3EB, 3FA, and 3FB are front views. Figure 3CA and 3CB This is a side view illustrating the manufacturing steps of the semiconductor package in an embodiment of the present invention.

[0029] Figure 4A This is a perspective top view of a semiconductor package in an embodiment of the present invention. Figure 4B This is a perspective bottom view of a semiconductor package in an embodiment of the present invention. Detailed Implementation

[0030] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the lead frame strip with a molded bus and the method for manufacturing semiconductor packages proposed in this invention. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, used only to facilitate and clarify the illustration of the embodiments of this invention. Please refer to the drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0031] Figure 1 This is a front view of the lead frame strip 100 in an embodiment of the present invention. The lead frame strip 100 includes a plurality of blocks 110. Although Figure 1 Only three blocks 112, 114, and 116 of the plurality of blocks 110 are shown, but the number of blocks included in the lead frame strip 100 can be adjusted as needed. Each block includes a molding bus 130, a first plurality of rows 140, a first plurality of molding gates 150, a second plurality of rows 160, and a second plurality of molding gates 170. The molding bus 130 extends along a first direction (Y direction), and the first plurality of rows 140 extends along a second direction (X direction) perpendicular to the first direction (Y direction) and is located on a first side (e.g., the right side) of the molding bus 130. The first plurality of molding gates 150 connect the molding bus 130 to the first plurality of rows 140. The second plurality of rows 160 extends along the second direction (X direction) and is located on a second side (e.g., the left side) of the molding bus 130, opposite to the first side (e.g., the right side). The second plurality of molding gates 170 connect the molding bus 130 to the second plurality of rows 160.

[0032] Each of the first plurality of rows 140 and the second plurality of rows 160 contains a plurality of lead frames 120. Although Figure 1 The diagram shows that each of the first plurality of rows 140 and the second plurality of rows 160 contains 6 lead frames 120, but the number of lead frames in each row can be adjusted as needed.

[0033] Each leadframe 120 includes a chip pad 122, a plurality of leads 124, and a plurality of connecting ribs 128. The plurality of leads 124 are connected to the leadframe 120, the number of connected leads being adjustable, and the plurality of leads extending along a first direction (Y direction). The plurality of connecting ribs 128 are connected to the chip pad 122, the number of connected ribs being adjustable, and the plurality of connecting ribs extending along a second direction (X direction). A molding bus 130 provides a channel for the injection of molding material, allowing the molding material to flow to a first plurality of molding gates 150 and a second plurality of molding gates 170, thereby filling the molding chamber corresponding to each row of leadframes in the first plurality of rows 140 and the second plurality of rows 160.

[0034] In an embodiment of the invention, the first plurality of rows 140 and the second plurality of rows 160 are symmetrical about the molding bus 130.

[0035] In an embodiment of the invention, the lead frame strip 100 further includes a plurality of saw marks 102 located at the outer periphery of the lead frame strip 100 and distributed along a second direction (X direction). Each saw mark 102 extends along a first direction (Y direction) and is aligned with the connection center between adjacent lead frames, between a lead frame and an adjacent molded bus, or between the outer periphery of a block.

[0036] In an embodiment of the invention, the lead frame strip 100 further includes a plurality of stamped marks 104, which are disposed between adjacent rows and extend along a second direction (X direction).

[0037] The plurality of leads 124 include one or more upper leads 123 connected to the chip pad 122, and one or more lower leads 125 separated from the chip pad 122. The one or more upper leads 123 and the one or more lower leads 125 are symmetrical about the center of the chip pad 122.

[0038] The plurality of connecting ribs 128 include a first connecting rib 127 and a second connecting rib 129, the first connecting rib 127 and the second connecting rib 129 being symmetrical about the center of the chip pad 122.

[0039] Figure 2 This is a flowchart of a semiconductor packaging manufacturing process 200 in an embodiment of the present invention. Figure 3A , 3B 3D, 3EA, 3EB, 3FA, and 3FB are front views. Figure 3CA , 3CB This is a side view showing the steps of manufacturing process 200. For simplicity, the diagram is... Figure 3A , 3B Only one block is represented in 3D, 3EA, 3EB, 3FA and 3FB. The number of blocks in the lead frame strip can be adjusted as needed. Figure 3CA , 3CB Only one semiconductor package is shown in the diagram; the number of semiconductor packages that can be manufactured from a single block can be adjusted as needed. Manufacturing process 200 can begin from step 202.

[0040] In step 202, refer to Figure 3A Provides a lead frame bar 300. The lead frame bar 300 includes... Figure 1 The multiple blocks 110 in the diagram are shown for simplification. Figure 3A Only one block 312 is shown. Each block includes a molding bus 330, a first plurality of rows 340, a first plurality of molding gates 350, a second plurality of rows 360, and a second plurality of molding gates 370. The molding bus 330 extends along a first direction (Y direction), and the first plurality of rows 340 extends along a second direction (X direction) perpendicular to the first direction (Y direction) and is located on a first side (e.g., the right side) of the molding bus 330. The first plurality of molding gates 350 connect the molding bus 330 to the first plurality of rows 340. The second plurality of rows 360 extends along the second direction (X direction) and is located on a second side (e.g., the left side) of the molding bus 330, opposite to the first side (e.g., the right side). The second plurality of molding gates 370 connect the molding bus 330 to the second plurality of rows 360.

[0041] Each of the first plurality of rows 340 and the second plurality of rows 360 contains a plurality of lead frames 320. Although Figure 3A The diagram shows that each of the first plurality of rows 340 and the second plurality of rows 360 contains 6 lead frames 320, but the number of lead frames in each row can be adjusted as needed.

[0042] Each leadframe 320 includes a chip pad 322, a plurality of leads 324, and a plurality of connecting ribs 328. The number of leads connected to the chip pad 322 is adjustable, and the plurality of leads extend along a first direction (Y direction). The plurality of connecting ribs 328 are connected to the chip pad 322, the number of connecting ribs is adjustable, and the plurality of connecting ribs extend along a second direction (X direction).

[0043] In an embodiment of the invention, the first plurality of rows 340 and the second plurality of rows 360 are symmetrical about the molding bus 330.

[0044] In an embodiment of the invention, the lead frame strip 300 further includes a plurality of saw marks 302 extending along a first direction (Y direction).

[0045] In an embodiment of the invention, the lead frame strip 300 further includes a plurality of stamped marks 304 extending along a second direction (X direction).

[0046] The plurality of leads 324 includes one or more upper leads 323 connected to the chip pad 322, and one or more lower leads 325 separated from the chip pad 322. The one or more upper leads 323 and the one or more lower leads 325 are symmetrical about the center of the chip pad 322.

[0047] The plurality of connecting ribs 328 include a first connecting rib 327 and a second connecting rib 329, the first connecting rib 327 and the second connecting rib 329 being symmetrical about the center of the chip pad 322. Step 204 is performed after step 202.

[0048] In step 204, refer to Figure 3B Multiple transistors 307 are installed. In embodiments of the present invention, the multiple transistors 307 are metal-oxide-semiconductor field-effect transistors (MOSFETs), and each transistor is cuboid in shape. Step 206 is performed after step 204.

[0049] In step 206, refer to Figure 3CA , 3CB The semiconductor package connects multiple metal clips 347 or multiple bonding wires 349. In one embodiment, the semiconductor package contains only multiple metal clips 347 (excluding multiple bonding wires 349); in another embodiment, the semiconductor package contains only multiple bonding wires 349 (excluding multiple metal clips 347). In yet another embodiment, the semiconductor package contains both multiple metal clips 347 and multiple bonding wires 349. Step 208 is performed after step 206.

[0050] In step 208, refer to Figure 3D This forms a molded package 390. The molded package 390 encapsulates a plurality of transistors 307, a plurality of metal clips 347 or a plurality of bonding wires 349, and the majority (greater than 50%) of the lead frame strip 300. The molding material is from... Figure 3A The material flows out of the molding bus 330, through the first plurality of molding gates 350 to the first plurality of rows 340, and simultaneously through the second plurality of molding gates 370 to the second plurality of rows 360. Step 210 is executed after step 208.

[0051] In step 210, refer to Figure 3EA , 3EB The stamping process is performed with reference to multiple stamping marks 304. Figure 3EA In a corresponding embodiment, a portion of each of the plurality of leads 324 is removed; in Figure 3EB In the corresponding embodiment, except Figure 3A Multiple metal segments 319 between multiple leads 324, and a portion of each lead in the multiple leads 324. Figure 3EA The stamping chamber 371 is smaller than Figure 3EB The stamping chamber 373 in the middle, therefore Figure 3EA The corresponding structure can provide better support for subsequent process steps. Step 212 is executed after step 210.

[0052] In step 212, refer to Figure 3FA , 3FB The sawing process is performed with reference to multiple sawing marks 302. Figure 3FA The multiple semiconductor packages 391 are separated from each other. Figure 3FB The multiple semiconductor packages 393 are separated from each other.

[0053] Figure 4A This is a perspective top view of a semiconductor package 400 manufactured by manufacturing process 200 in an embodiment of the present invention. Figure 4B This is a perspective bottom view. The top of the semiconductor package 400 includes a first straight edge 420, a second straight edge 422, a first rounded corner edge 440, and a second rounded corner edge 442. The first rounded corner edge 440 and the second rounded corner edge 442 are formed by the stamping process of step 210 (without changing the molded package, forming leads); the first straight edge 420 and the second straight edge 422 are formed by the sawing process of step 212. The advantages of the stamping process in step 210 include: shorter process time, better wettability of the leads 460 (the cuboid portion of each lead in the plurality of leads 460 protrudes from the molded package 490, i.e., protrudes from the molded package 490), and easier picking up of the semiconductor package in the assembly step (thanks to the first rounded corner edge 440 and the second rounded corner edge 442). The advantages of the sawing process in step 212 include: compact semiconductor package structure (higher lead frame density in the lead frame strip, saving space), flexible semiconductor package size, and no protruding connecting ribs 470 in the molded package of the semiconductor package 490.

[0054] The first straight edge 420 extends along the first direction (Y direction), and the second straight edge 422 extends along the first direction (Y direction) and is opposite to the first straight edge 420; the first rounded edge 440 extends along the second direction (X direction), and the second rounded edge 442 extends along the second direction (X direction) and is opposite to the first rounded edge 440.

[0055] The molded package 490 encloses the shortened portion of each of the multiple connecting ribs, with only the sawn facet 471 of each of the multiple connecting ribs 470 exposed from the molded package 490.

[0056] In an embodiment of the invention, the bottom surface 485 of the lead frame 481 is exposed from the molded package 490.

[0057] Those skilled in the art will understand that modifications can be made to the embodiments disclosed herein. For example, the number of blocks included in the lead frame strip 100 can be adjusted. Other modifications may occur to those skilled in the art, and all such modifications are considered to fall within the scope of protection of this invention as defined by the claims.

[0058] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0059] In the description of this invention, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0060] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0061] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0062] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A leadframe strip, characterized by, include: The system comprises multiple blocks, each block including: a molding bus extending along a first direction; a first plurality of rows extending along a second direction perpendicular to the first direction, the first plurality of rows being located on a first side of the molding bus; a first plurality of molding gates connecting the molding bus to the first plurality of rows; a second plurality of rows extending along the second direction, the second plurality of rows being located on a second side of the molding bus opposite to the first side; and a second plurality of molding gates connecting the molding bus to the second plurality of rows; each of the first plurality of rows and the second plurality of rows includes: a plurality of lead frames, each lead frame including: a chip pad; a plurality of leads extending along the first direction; and a plurality of connecting ribs connected to the chip pad and extending along the second direction.

2. The leadframe strip of claim 1, wherein, The first plurality of rows and the second plurality of rows are symmetrical about the molding bus.

3. The lead frame strip according to claim 1, characterized in that, It also includes multiple saw marks extending along the first direction.

4. The lead frame strip according to claim 1, characterized in that, It also includes multiple stamping marks extending along the second direction.

5. The lead frame strip according to claim 1, characterized in that, The plurality of leads include: one or more upper leads connected to the chip pads; and one or more lower leads separated from the chip pads; wherein the one or more upper leads and the one or more lower leads are symmetrical about the center of the chip pads.

6. The lead frame strip according to claim 1, characterized in that, The plurality of connecting ribs includes: a first connecting rib; and a second connecting rib; wherein the first connecting rib and the second connecting rib are symmetrical about the center of the chip pad.

7. A method for manufacturing a semiconductor package, characterized in that, The method includes the following steps: providing a lead frame strip, the lead frame strip comprising: a plurality of blocks, each block comprising: a molding bus extending along a first direction; a first plurality of rows extending along a second direction perpendicular to the first direction, the first plurality of rows being located on a first side of the molding bus; a first plurality of molding gates connecting the molding bus to the first plurality of rows; a second plurality of rows extending along the second direction, the second plurality of rows being located on a second side of the molding bus opposite to the first side; and a second plurality of molding gates connecting the molding bus to the second plurality of rows; each of the first plurality of rows and the second plurality of rows comprising: a plurality of lead frames, each lead frame comprising: a chip pad; a plurality of leads extending along the first direction; and a plurality of connecting ribs connected to the chip pad and extending along the second direction; mounting a plurality of transistors; connecting a plurality of metal clips or a plurality of bonding wires; forming a molded package, the molded package encapsulating the plurality of transistors and the plurality of metal clips or the plurality of bonding wires; performing a stamping process; and performing a sawing process to separate the semiconductor package from adjacent semiconductor packages.

8. The method according to claim 7, characterized in that, The first plurality of rows and the second plurality of rows are symmetrical about the molding bus.

9. The method according to claim 7, characterized in that, It also includes multiple saw marks extending along the first direction.

10. The method according to claim 7, characterized in that, It also includes multiple stamping marks extending along the second direction.

11. The method according to claim 7, characterized in that, The plurality of leads include: one or more upper leads connected to the chip pads; and one or more lower leads separated from the chip pads; wherein the one or more upper leads and the one or more lower leads are symmetrical about the center of the chip pads.

12. The method according to claim 7, characterized in that, The plurality of connecting ribs includes: a first connecting rib; and a second connecting rib; wherein the first connecting rib and the second connecting rib are symmetrical about the center of the chip pad.

13. The method according to claim 7, characterized in that, The top of the semiconductor package includes: a first straight edge extending along the first direction; a second straight edge extending along the first direction and opposite to the first straight edge; a first rounded edge extending along the second direction; and a second rounded edge extending along the second direction and opposite to the first rounded edge.

14. The method according to claim 13, characterized in that, The cuboid portion of each of the plurality of leads is exposed from the molded package.

15. The method according to claim 13, characterized in that, The molded package encapsulates the shortened portion of each of the plurality of connecting ribs, with only the sawn surface of each of the plurality of connecting ribs exposed from the molded package.

16. The method according to claim 7, characterized in that, In the step of performing the stamping process, a portion of each of the plurality of leads is removed.

17. The method according to claim 7, characterized in that, Each lead frame includes a plurality of metal segments located between the plurality of leads; and wherein, in the step of performing the stamping process, the plurality of metal segments and a portion of each of the plurality of leads are removed.

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