Lead frame fixture

Abstract

A lead frame fixing device is provided on a stage, and is used to apply a force toward the stage to a lead frame placed on the stage. The lead frame fixing device includes at least one pressure foot, which is at least one of a first pressure foot, a second pressure foot, or a third pressure foot: the first pressure foot contacts a lead frame pin and applies a force toward the stage to the lead frame pin; the second pressure foot contacts a base island of the lead frame and applies a force toward the stage to the base island of the lead frame; and the third pressure foot contacts a connecting rib of the lead frame and applies a force toward the stage to the connecting rib of the lead frame.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor packaging, and in particular to a fixing device for a lead frame. Background Art

[0002] In the chip packaging process, the low-cost wire bonding process is mostly used, that is, wire bonding is performed using a lead frame bonding device.

[0003] Figure 1A FIG. 1 is a top view of a fixing device for fixing a lead frame in a wire bonding process in the prior art. Figure 1B yes Figure 1A A partial enlarged view of the Figure 1A As shown, in the lead frame wire bonding process, a lead frame 1 with a chip 2 attached thereto is placed on a stage 3 and the lead frame 1 is fixed by a fixing device 4 .

[0004] like Figure 1A As shown, the fixing device 4 has a plurality of presser feet to correspond to different areas of the lead frame 1. For example, Figure 1A As shown, the fixing device 4 has a first presser foot 41, a second presser foot 42, a third presser foot 43 and a fourth presser foot 44. Specifically, as Figure 1B As shown, the first presser foot 41 is used to fix the connecting ribs between the pins on both sides of the lead frame 1, the second presser foot 42 is used to fix the pins on both sides of the lead frame 1, the third presser foot 43 is used to fix the base island of the lead frame 1 attached to the chip 2, and the fourth presser foot 44 is used to fix the connecting ribs between adjacent base islands.

[0005] The applicant's research shows that there are problems with the multiple pressure feet of the fixing device 4: (1) The inclination angle of the second pressure foot 42 corresponding to the single-side pin of the lead frame 1 is too large, so that when pressing, the second pressure foot 42 applies uneven pressure to the pin of the lead frame 1, causing the wire to jump easily; (2) The third pressure foot 43 corresponding to the base island of the lead frame 1 for attaching the chip 2 is a bifurcated design, which is equivalent to forming two force application points at the base island of the lead frame 1, especially at the edge of the base island, resulting in uneven pressure at the edge of the base island and loose fitting between the lead frame 1 and the stage. Therefore, during the wire bonding process, the connection between the wire and the solder joint is not firm, which easily leads to failure of the flying wire or wire pulling test; (3) Only a single fourth pressure foot 44 is used to fix the connecting rib between adjacent base islands of the lead frame 1, forming only one force application point, resulting in the lead frame 1 being slightly tilted at this position due to uneven force. Therefore, there are problems such as unstable wire bonding and easy wire jumping during the wire bonding process.

[0006] Therefore, it is necessary to provide a new fixing device for a lead frame to overcome the above-mentioned defects. Summary of the Invention

[0007] The purpose of this application is to provide a fixing device for a lead frame, which significantly improves the fit between the lead frame and the stage during the wire bonding process through a reasonable pressure foot structure setting, thereby significantly improving the quality of the wire bonding.

[0008] To achieve the above-mentioned purpose, according to one aspect of the present application, a lead frame fixing device is provided, which is arranged on a stage and is used to apply a force toward the stage to a lead frame placed on the stage. The lead frame fixing device includes at least one pressure foot, and the pressure foot is at least one of a first pressure foot, a second pressure foot, or a third pressure foot: the first pressure foot contacts a pin of the lead frame and applies a force toward the stage to the pin of the lead frame; the second pressure foot contacts a base island of the lead frame and applies a force toward the stage to the base island of the lead frame; the third pressure foot contacts a connecting rib of the lead frame and applies a force toward the stage to the connecting rib of the lead frame.

[0009] In some embodiments, the first presser foot has a force-applying end, the force-applying end of the first presser foot contacts the pin of the lead frame and applies a force toward the worktable to the pin of the lead frame; wherein the projection of the force-applying end of the first presser foot on the lead frame is perpendicular to the pin of the lead frame.

[0010] In some embodiments, the second pressure foot has a force-applying end, the force-applying end of the second pressure foot contacts a base island of the lead frame and applies a force toward the worktable to the base island of the lead frame; wherein the contact between the force-applying end of the second pressure foot and the base island of the lead frame is line contact.

[0011] In some embodiments, a projection of a contact point between the force-applying end of the second pressure foot and the base island of the lead frame on the stage is parallel to a projection of a side edge of the base island of the lead frame on the stage.

[0012] In some embodiments, the third pressure foot has a force-applying end, the force-applying end of the third pressure foot contacts the connecting rib of the lead frame and applies a force toward the worktable to the connecting rib of the lead frame; wherein the contact between the force-applying end of the third pressure foot and the connecting rib of the lead frame is surface contact.

[0013] In some embodiments, a projection of the force-applying end of the third pressure foot on the lead frame at least covers a portion of the connecting rib of the lead frame.

[0014] In some embodiments, the connecting rib connects two adjacent base islands in the lead frame.

[0015] In some embodiments, the lead frame fixing device further includes a fixing frame, and the presser foot is connected to the fixing frame.

[0016] In some embodiments, the first presser foot has a fixed end connected to the fixed frame; the second presser foot has a fixed end connected to the fixed frame; and the third presser foot has a fixed end connected to the fixed frame.

[0017] In the present application, by setting a reasonable pressure foot structure, the fit between the lead frame and the stage during the wire bonding process is significantly improved, so that the quality of the wire bonding is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1A It is a top view of a fixing device used in the wire bonding process in the prior art for fixing a lead frame;

[0019] Figure 1B Shown is Figure 1A A partial enlarged view of

[0020] Figure 2 is a schematic structural diagram of a lead frame fixing device according to an embodiment of the present application;

[0021] Figure 3 yes Figure 2 A partial enlarged view of . DETAILED DESCRIPTION

[0022] The following describes the technology of the present application in detail in conjunction with specific embodiments. It should be noted that the following specific embodiments are only intended to help those skilled in the art understand the present application, and are not intended to limit the present application.

[0023] like Figure 2 As shown, in this application, a lead frame fixing device 100 is provided, which is used to be set on a stage 200 to apply a force F toward the stage 200 to a lead frame 300 placed on the stage 200. It can be understood by those skilled in the art that the direction of the force F is Figure 2 The direction indicated by the middle arrow is a direction almost perpendicular to the surface of the stage 200 .

[0024] like Figure 2 As shown, in this embodiment, the lead frame fixing device 100 has a plurality of presser feet and a fixing frame 140 for connecting with the plurality of presser feet to fix the presser feet. In the lead frame fixing device 100 of the present application, there are a plurality of presser feet, such as Figure 2 The four first presser feet 110, the four second presser feet 120 and the two third presser feet 130 are shown. It will be understood by those skilled in the art that the lead frame fixing device 100 described in the present application can adjust the specific number of the first presser feet 110, the second presser feet 120 and the third presser feet 130 based on the structure of different lead frames 300, and is not limited to the number shown in the drawings of the present application. In addition, it will be understood by those skilled in the art that the first presser feet 110, the second presser feet 120 and the third presser feet 130 can be included in a lead frame fixing device 100 separately, or can be included in a lead frame fixing device 100 in any combination of two or three, and is not limited to the combination shown in the drawings of the present application.

[0025] That is to say, if Figure 2 and Figure 3 As shown, in the present application, the lead frame fixing device 100 includes at least one presser foot, which is at least one of a first presser foot 110, a second presser foot 120 or a third presser foot 130:

[0026] like Figure 3 As shown, the first presser foot 110 contacts a pin 301 of the lead frame 300 , and is used to apply a force toward the stage 200 to the pin 301 of the lead frame 300 ;

[0027] like Figure 3 As shown, the second presser foot 120 contacts a base island 302 of the lead frame 300 and applies a force toward the stage 200 to the base island 302 of the lead frame 300 ;

[0028] like Figure 3 As shown, the third presser foot 130 contacts a connecting rib 303 of the lead frame 300 , and applies a force toward the loading platform to the connecting rib 303 of the lead frame 300 .

[0029] The following, combined Figure 2 and Figure 3 The specific structures of the first presser foot 110 , the second presser foot 120 and the third presser foot 130 of the lead frame fixing device 100 are described in detail.

[0030] like Figure 2 and Figure 3 As shown, the first presser foot 110 has a force-applying end 111 and a fixing end 112 for connecting with the fixing frame 140. Figure 3As shown, the force-applying end 111 of the first presser foot 110 contacts the pin 301 of the lead frame 300 and applies a force toward the stage 200 to the pin 301 of the lead frame 300; wherein the projection of the force-applying end 111 of the first presser foot 110 on the lead frame 300 is perpendicular to the pin 301 of the lead frame 300. Since the directions of the pins 301 on the same side of the lead frame 300 are consistent, as shown in FIG. Figure 3 Thus, the multiple force application points of the plurality of first presser feet 110 corresponding to the pins 301 on the lead frame 300 are formed on a straight line, so that the force on the pin side of the lead frame 300 is more uniform.

[0031] like Figure 2 and Figure 3 As shown, the second presser foot 120 has a force-applying end 121 and a fixing end 122 for connecting with the fixing frame 140. Figure 3 As shown, the force-applying end 121 of the second presser foot 120 contacts a base island 302 of the lead frame 300 and applies a force toward the stage 200. The contact between the force-applying end 121 of the second presser foot 120 and the base island 302 of the lead frame 300 is linear. That is, the projection of the point of contact between the force-applying end 121 of the second presser foot 120 and the base island 302 of the lead frame 300 on the stage 200 is parallel to the projection of one side of the base island 302 of the lead frame 300 on the stage 200. In other words, the force-applying end 121 of the second presser foot 120 is substantially close to the edge of a chip (not shown) attached to the base island 302. Thus, the second pressure foot 120 has a larger force application area for the lead frame 300, so that the force received by the base island 302 of the lead frame 300 is more uniform and the fit with the stage 200 is closer, thereby ensuring the quality of the bonding wire during the wire bonding process.

[0032] like Figure 2 and Figure 3 As shown, the third presser foot 130 has a force-applying end 131 and a fixing end 132 for connecting with the fixing frame 140. Figure 3 As shown, the force-applying end 131 of the third presser foot 130 contacts the connecting rib 303 of the lead frame 300 and applies a force toward the stage 200 to the connecting rib 303 of the lead frame 300. Figure 3 As shown, the connecting rib 303 is particularly located between two adjacent base islands 302 in the lead frame 300. Figure 3As shown, the force-applying end 131 of the third pressure foot 130 makes surface contact with the connecting rib 302 of the lead frame 300. This allows the third pressure foot 130 to apply a more stable and uniform force to the connecting rib 303 between two adjacent base islands 302 of the lead frame 300, thereby ensuring a tighter fit between the lead frame 300 and the stage 200 and preventing a slight warping of one side (the side without pins) of the lead frame 300. This further ensures wire bonding quality during the wire bonding process.

[0033] Therefore, in the present application, through the above-mentioned three different pressure foot structure designs corresponding to different positions of the lead frame 300, the force application state of each pressure foot on the lead frame 300 is more reasonably adjusted, thereby significantly improving the fit between the lead frame and the stage during the wire bonding process, and significantly improving the quality of the welding wire.

[0034] This application has been described with reference to the above-described embodiments. However, the above-described embodiments are merely exemplary embodiments of the present application. It should be noted that the disclosed embodiments do not limit the scope of this application. On the contrary, modifications and equivalents encompassed by the spirit and scope of the claims are intended to be within the scope of this application.

Claims

1. A lead frame fixing device, provided on a stage, for applying a force toward the stage to a lead frame placed on the stage, characterized in that: The lead frame fixing device includes a fixing frame and a plurality of first presser feet, a plurality of second presser feet, and a plurality of third presser feet connected to the fixing frame. The plurality of first presser feet respectively contact a plurality of pins of the lead frame and apply a force toward the stage to the pins of the lead frame; the plurality of first presser feet each have a force-applying end, projections of the force-applying ends of the plurality of first presser feet on the lead frame are perpendicular to the pins of the lead frame, and a plurality of force-applying points of the plurality of first presser feet on the lead frame are formed on a straight line; The plurality of second pressure feet contact the base island of the lead frame and apply a force toward the stage to the base island of the lead frame; Each of the plurality of second presser feet has a force-applying end, and the force-applying ends of the plurality of second presser feet are in line contact with the base island of the lead frame. The projections of the contact points of the force-applying ends of the plurality of second presser feet with the base island of the lead frame on the stage are parallel to the projection of one side of the base island of the lead frame on the stage, and the force-applying ends of the plurality of second presser feet are close to the edge of the chip attached to the base island. The plurality of third pressure feet contact the connecting ribs of the lead frame and apply a force toward the stage to the connecting ribs of the lead frame; the plurality of third pressure feet each have a force-applying end, the force-applying ends of the plurality of third pressure feet contact the connecting ribs of the lead frame, the force-applying ends of the third pressure feet are in surface contact with the connecting ribs of the lead frame, and at least cover a portion of the connecting ribs of the lead frame, wherein the connecting ribs connect two adjacent base islands in the lead frame; The plurality of first presser feet, the plurality of second presser feet and the plurality of third presser feet respectively correspond to different presser foot structure designs at different positions of the lead frame.

2. The lead frame fixing device according to claim 1, wherein: The first presser foot has a fixed end connected to the fixed frame; the second presser foot has a fixed end connected to the fixed frame; and the third presser foot has a fixed end connected to the fixed frame.

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