Warping improvement device of lead frame

Abstract

The utility model discloses a warping improvement device for a lead frame, and belongs to the field of detection jigs. The warping improving device comprises a pressing foot and an embedded adjusting structure, the embedded adjusting structure comprises a ball and a coil, a hollow area exists in the middle of the pressing foot, cavities are formed in the two side edges of the periphery of the hollow area respectively, openings of the cavities face the hollow area, the ball is embedded into the cavities, and the coil is embedded into the hollow area. The spiral ring is arranged in the hollow area, and a part of the spiral ring is embedded into the cavity and located above the balls. In the ultrasonic scanning process, the warping improving device can keep the flat state of the lead frame, and the problem of scanning image distortion or overlapping caused by warping is avoided. By adjusting the length and the direction of the pressing pin, the lead frame can be kept at the same plane height in the scanning process, so that the scanning quality and the scanning efficiency are improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of detection fixture relates to a lead frame warping improvement device. BACKGROUND

[0002] The lead frame is a kind of key structural member, which is a chip carrier of integrated circuit, realizes the electrical connection between internal circuit lead-out end and external lead by bonding material, forms electrical loop, and is important basic material of integrated circuit industry.The lead frame is usually rectangular, and a plurality of same lead frame units are arranged on the upper or lower surface.

[0003] The ultrasonic scanning technology is mainly used for detecting defects such as delamination, cavity and crack in the packaging product, can accurately display the internal structure of the device without damaging the product, and position the defect type and position, and at present, this non-destructive testing method is widely used in the field of semiconductor packaging.The detection principle of the technology is that the transducer of the probe transmits ultrasonic waves to the inside of the sample in the form of pulse through water medium, since ultrasonic waves will be reflected at the interface of different materials, once there is a defect in the product, there will be a distinct echo, after the computer distinguishes and image processing, the scanning imaging graph of the plastic packaging product is finally generated.

[0004] Generally, the whole lead frame plastic packaging product after plastic packaging and electroplating will be subjected to ultrasonic scanning to determine whether there are delamination, cavity and other problems in the product.In the early scanning process, the scanning results are often inconsistent due to the warping of the lead frame, which affects the efficiency of product quality problem detection.

[0005] At present, for the problem of product warping in the ultrasonic scanning process, the existing processing method is usually to press multiple iron blocks on the warped parts of the frame to keep the lead frame flat.The above method has the following problems: if the frame is severely warped, the light quality iron block cannot correct the frame warping, but the heavy iron block will affect the levelness of the bottom loading platform, which will cause abnormal scanning results, and the loading platform has also been broken due to the load, and the operator needs to adjust the position of the iron block according to the specification of the lead frame, which is time-consuming and laborious. UTILITY MODEL CONTENTS

[0006] In order to overcome the shortcomings of the prior art, the purpose of the utility model is to provide a lead frame warping improvement device to solve the problems of limited correction effect, influence on the levelness of the loading platform, risk of damage to the loading platform, complex operation, time-consuming and possible abnormal scanning results in the method of treating warping by iron block.

[0007] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0008] The utility model provides a kind of warping improvement device of lead frame, including pressing foot and embedded adjusting structure, the embedded adjusting structure includes ball and spiral, the middle part of pressing foot exists hollow area, the two sides of the periphery of hollow area are respectively provided with cavity, the opening of cavity faces hollow area, the ball is embedded in the inside of cavity, the spiral is arranged at hollow area, and part of spiral is embedded in the inside of cavity and located above ball.

[0009] In an embodiment, the inside of the spiral is provided with a screw, and the lower part of the spiral is provided with a fixing device for connecting the warping improvement device and the object table.

[0010] In an embodiment, the fixing device includes a spring located below the spiral and in contact with the spiral, the spring is sleeved on the screw rod of the screw, the bottom of the screw is provided with a bottom thread, and the bottom thread is matched with the thread in the inner groove of the object table.

[0011] In an embodiment, the head of the screw is located above the spiral, and the screw rod of the screw sequentially passes through the spiral and the spring.

[0012] In an embodiment, the pressing foot includes a force applying part, a first connecting part, a middle part, a second connecting part and a pressing part connected in sequence and integrally formed, the force applying part, the middle part and the pressing part are in step-down shape; the force applying part is suspended, and the pressing part is in contact with the lead frame product.

[0013] In an embodiment, the force applying part, the middle part and the pressing part are parallel to each other and gradually lower, and the first connecting part and the second connecting part are parallel to each other.

[0014] In an embodiment, the balls are arranged side by side in the cavities.

[0015] In an embodiment, the depth of the cavity is equal to the diameter of the ball, and the height of the cavity is greater than or equal to the sum of the diameter of the ball and the thickness of the spiral.

[0016] In an embodiment, the outer ring diameter of the spiral is less than or equal to the length of the cavity, and the inner ring diameter of the spiral is less than the distance between the two cavities.

[0017] In an embodiment, the periphery of the cavity is left with excess material as an edge part, the edge part includes a top edge and a bottom edge distributed upward and downward, the bottom edge is provided with a baffle, the height of the baffle is not greater than the diameter of the ball, and not less than the radius of the ball.

[0018] Compared with the prior art, the utility model has the following beneficial effects:

[0019] The utility model provides a kind of warping improvement device of lead frame, the traditional iron block processing method possibly due to unable accurate adjustment pressing degree, leading to limited correction effect, cannot completely eliminate warping.The warping improvement device provided by the utility model realizes accurate adjustment and stable pressing by the combination of pressing foot and embedding adjustment structure.Hollow region in the middle of pressing foot and two sides cavity provide space for the embedding of ball and spiral, and the flexibility of the ball enables the pressing foot to flexibly adjust the length before and after and the direction of two sides around the spiral, ensuring the accuracy of pressing.At the same time, the embedding of the spiral and the cavity ensures the stability of the pressing foot, avoiding deviation or falling during the pressing process.The device can freely adjust the pressing angle and length, meeting the needs of various lead frame specifications.The middle part of the pressing foot is provided with a cavity and embedded with a ball, so that the pressing foot can rotate 360 degrees around the fixed spiral and can be adjusted before and after to adapt to the edge part of lead frame of different sizes.This design enables the device to respond to lead frames of different packaging types without the need to replace different pressing tools, greatly improving the convenience and efficiency of use.During the ultrasonic scanning process, the warping improvement device can maintain the flatness of the lead frame, avoiding the distortion or overlapping problem of the scanning image caused by warping.By adjusting the length and direction of the pressing foot, the lead frame during scanning can be ensured to maintain the same plane height, thereby improving the scanning quality and efficiency.

[0020] Further, the pressing foot is designed in a stepped manner, facilitating force application and accurate pressing of lead frame products, and improving the effect of warping improvement.Meanwhile, the embedding adjustment structure of the ball and the spiral can flexibly adjust the length and angle according to the size of the frame, ensuring the flatness of the frame.

[0021] Further, when using an iron block for correction, the uneven weight of the iron block or improper placement may affect the levelness of the object table, thereby affecting the accuracy of the scanning result.The warping improvement device provided by the utility model is stably connected with the object table through the fixing device, ensuring the stability and reliability of the device.The fixing device includes a spring and a screw, the spring is located below the spiral and in contact with the spiral, and is sleeved on the screw rod of the screw, the bottom thread processed on the screw rod is matched with the inner groove thread of the object table, realizing flexible fixing and adjustment.This design not only ensures the stability of the device, but also avoids affecting the levelness of the object table.

[0022] Further, in the iron block processing method, excessive direct contact between the iron block and the object table may damage the surface of the object table and affect subsequent use.The lower buffer spring of the pressing foot of the above-mentioned warping improvement device can reduce the direct impact on the object table during pressing, reducing the risk of damage to the object table.

[0023] Further, in the iron block processing method, the iron block may interfere with the normal operation of the ultrasonic scanning probe due to the presence and improper position of the iron block, resulting in abnormal scanning results. The design of the above-described warping improvement device fully considers the working requirements of the ultrasonic scanning probe and provides sufficient adjustment space, so that the operator can adjust the position and angle of the pressing foot according to the actual situation to avoid interfering with the normal operation of the scanning probe. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a top view of the warping improvement device of the present application;

[0025] Figure 2 It is a side view of the warping improvement device of the present application;

[0026] Figure 3 It is a schematic diagram of the ultrasonic scanning process of the present application;

[0027] Figure 4 It is a cross-sectional view of the pressing foot;

[0028] Figure 5 It is a schematic diagram of the fixing device;

[0029] Figure 6 It is a schematic diagram of the embedded adjustment structure;

[0030] Wherein: 1-warping improvement device; 2-lead frame product; 3-carrier; 4-scanning probe; 5-roller ball; 11-pressing foot; 12-screw; 13-spiral; 14-fixing device; 111-cavity; 112-intermediate part; 141-spring; 142-screw; 143-bottom thread. DETAILED DESCRIPTION

[0031] In order to make the personnel in the technical field better understand the present application scheme, the technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the scope of protection of the present application.

[0032] It should be noted that the terms "first", "second", and the like in the description and in the claims of the utility model and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the utility model described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to the clearly listed steps or units, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0033] The utility model will be described in further detail below in conjunction with the drawings:

[0034] Referring to Figures 1 to 6 As shown in the figure, the utility model provides a warping improvement device of lead frame, through pressing foot 11 and embedding adjustment structure, realize accurate adjustment and stable pressing. Among them, embedding adjustment structure includes ball 5 and spiral 13, the hollow area in the middle of pressing foot 11 and both sides cavities 111 provide space for the embedding of ball 5 and spiral 13, and facilitate the adjustment of pressing degree. Specifically, the middle part 112 of pressing foot 11 has a hollow area, and cavities 111 are respectively arranged on the two sides of the periphery of the hollow area, the opening of cavity 111 faces the hollow area, ball 5 is embedded in the inside of cavity 111, and spiral 13 is arranged at the hollow area, and part of spiral 13 is embedded in the inside of cavity 111 and located above ball 5.

[0035] In a specific embodiment, screw 12 is arranged inside spiral 13, and lower fixing device 14 is configured to ensure the stable connection between warping improvement device 1 and object table 3, improve the stability and reliability of the device. Fixing device 14 includes spring 141, spring 141 is located below spiral 13 and contacts spiral 13, and is sleeved on the screw rod 142 of screw 12, the bottom thread 143 machined on the screw rod 142 of screw 12 is matched with the inner groove thread of object table 3, and flexible fixing and adjustment are realized. The inside circle diameter of spiral 13 is equal to the diameter of screw rod 142, the head of screw 12 is located above spiral 13, and screw rod 142 passes through spiral 13 and spring 141 in sequence to facilitate the installation process and improve the assembly efficiency.

[0036] In an embodiment, the pressing foot 11 is designed in steps, and comprises a force applying part, a first connecting part, the intermediate part 112, a second connecting part and a pressing part connected in sequence and integrally formed, the force applying part, the intermediate part 112 and the pressing part are lowered in sequence, facilitating force applying and accurate pressing of the lead frame product 2, and improving the effect of improving warping.

[0037] Further, the force applying part, the intermediate part 112 and the pressing part are parallel to each other and gradually lowered, and the first connecting part and the second connecting part are also parallel to each other, ensuring the uniformity and stability of pressing.

[0038] In an embodiment, the balls 5 are arranged side by side in the cavities 111, and specifically, the depth of the cavity 111 is equal to the diameter of the ball 5, and the height of the cavity 111 is greater than or equal to the sum of the diameter of the ball 5 and the thickness of the coil 13, ensuring the stable embedding of the ball 5 and the coil 13.

[0039] In an embodiment, the outer diameter of the coil 13 is less than or equal to the length of the cavity 111, and the inner diameter of the coil 13 is less than the distance between the two cavities 111, ensuring that the coil 13 can be smoothly embedded in the cavity 111.

[0040] More specifically, in an embodiment, as shown in Figure 6 , the outer diameter of the coil 13 is equal to the length of the cavity 111, and the inner diameter of the coil 13 is less than the distance between the two cavities 111.

[0041] More specifically, in another embodiment, as shown in Figure 1 and Figure 2 , the outer diameter of the coil 13 is less than the length of the cavity 111, and the inner diameter of the coil 13 is less than the distance between the two cavities 111.

[0042] In an embodiment, the periphery of the cavity 111 is provided with a surplus as an edge part, and the edge part comprises a top edge and a bottom edge distributed upward and downward, and a baffle is arranged on the bottom edge, and the height of the baffle is not greater than the diameter of the ball 5 and not less than the radius of the ball 5. The height of the baffle of the edge part of the periphery of the cavity 111 is moderate, which prevents the ball 5 from falling off and ensures smooth rolling of the ball 5, improving the safety and stability of the device.

[0043] The utility model provides a kind of warping improving device of lead frame, it is for a kind of device in ultrasonic scanning process corrects lead frame warping, device plan view as shown in Figure 1 , in use process, lead frame product 2 is placed on object table 3, and using warping improving device 1 is pressed correction.

[0044] The overall detail view of the warpage improvement device 1 is shown in Figure 1 and Figure 2 The overall device of the warpage improvement device 1 is composed of four parts, namely, the pressing foot 11, the screw 12, the screw ring 13 and the fixing device 14. After the lead frame product 2 after plastic packaging is placed on the object table 3, the front end pressing part of the pressing foot 11 of the warpage improvement device 1 is pressed and fixed on both sides of the frame edge, the middle part 112 of the pressing foot 11 is matched with the screw ring 13, and the tail force part of the pressing foot 11 is suspended. The middle part 112 has a hollow area, cavities 111 are respectively formed on the two side edges of the periphery of the hollow area, and the ball 5 and the screw ring 13 are embedded in the cavities 111. The length and the angle can be adjusted according to the size of the frame, and the flatness of the frame is ensured.

[0045] Among them, the pressing foot 11 plays a pressing role and is fixed on both sides of the screw ring 13. The screw ring 13 is sleeved on the screw rod 142 of the screw 12 and can be adjusted up and down. The screw 12 above the screw ring 13 is a screw, and the fixing device 14 below the screw ring 13 is in contact with the spring 141 in the fixing device 14.

[0046] The device side view is shown in Figure 3 During the ultrasonic scanning process, the scanning probe 4 reciprocates above the object table 3, and the device is distributed on both sides of the object table 3. In the figure, the pressing foot 11 is installed above the fixing device 14. After the product is placed, the ultrasonic scanning probe 4 is adjusted so that the height of the scanning probe 4 is higher than the height of the device. The pressing part of the tail of the pressing foot 11 is pressed downward, the force part of the front end of the pressing foot 11 is suspended and lifted and pressed on the edge of the lead frame product 2, and the warpage of the frame product is pressed and corrected. The fixing device 14 is installed in the inner groove device opened on both sides of the object table 3 and mainly plays a fixing and adjusting role.

[0047] Figure 4 It is the sectional view of the pressing foot 11. The overall shape of the pressing foot 11 is stepped. The cavities 111 are formed in the middle part 112 of the pressing foot 11, and a plurality of side-by-side balls 5 are embedded in the cavities 111. By using the rolling action of the bottom ball 5, the pressing foot 11 can flexibly adjust the length of the front and back and the direction of the two sides around the screw ring 13.

[0048] Figure 5The bottom part of the screw 12 in the warping improvement device 1 is embedded in the circular hole on both sides of the object table 3, the lower half of the circular hole is etched thread, and the screw rod 142 is used for fixing. The upper half of the screw rod 142 is externally sleeved with the spring 141, and the pressing foot 11 is conveniently adjusted. The fixing device 14 comprises the spring 141, the screw rod 142 in the screw 12, and the bottom thread 143 processed at the bottom of the screw 12. The screw rod 142 is put into the circular groove through the spring 141 and is screwed into the circular groove in the direction of the bottom thread 143, so as to play a fixing screw role. The spring 141 is in contact with the screw ring 13, and the spring 141 can provide an upward supporting force and a downward pressing force for the screw ring 13.

[0049] Figure 6 The sectional view of the embedded adjustment structure is shown. The cavity 111 of the pressing foot 11 is embedded with a plurality of balls, and the screw ring 13 cooperates with the balls to form an adjustment device, which is used for flexibly adjusting the length and angle of the pressing foot 11. The screw ring 13 is embedded above the balls 5, and when adjustment is needed, the direction of the pressing foot 11 can be flexibly converted left and right, and the length of the pressing foot 11 can be flexibly adjusted forward and backward. At the same time, the screw ring 13 is embedded in the cavity 111, so that the pressing foot 11 cannot be separated from the control of the screw 12.

[0050] The warping improvement device of the lead frame is used for improving warping of the lead frame during ultrasonic scanning. The warping improvement device is used for solving the problem that different interfaces appear in the same scanning layer during ultrasonic scanning of the plastic package lead frame product 2 which is warped. Three warping improvement devices 1 are installed on both sides of the object table 3, so that the lead frame during scanning is kept in a flat state, the same layer scanning does not appear multi-layer image results, and the scanning quality and efficiency are improved.

[0051] The object table 3 provided by the warping improvement device of the lead frame is provided with circular holes on both sides, and three circular holes (inner grooves) are drilled at the edge positions of both sides of the object table 3. The fixing device 14 is installed in the circular hole (inner groove), and the circular hole (inner groove) is processed with threads, which are matched with the bottom thread 143 of the screw 12 in the fixing device 14. The pressing foot 11 in the warping improvement device 1 is installed above the circular hole. The installation device on both sides of the object table 3 saves space, is simple and convenient, and the single device detail view is shown in the accompanying drawings. Figure 1 .

[0052] Considering that the object table needs to be soaked in water medium for a long time during scanning, the screw 12 and the spring 12 used in the utility model need to be made of stainless steel material, so as to prevent rusting after long-time soaking in water.

[0053] In addition, the warping improvement device of the lead frame can freely adjust the pressing angle and length, and meets various specifications of the lead frame. The specifications of the lead frame usually include SOP, DIP, LQFP, QFN, DFN and other packaging forms, and the specifications of the lead frame of each packaging type are different. When ultrasonic scanning is performed, the size of the frame needs to be adjusted. The warping improvement device 1 provided by the utility model considers the adjustability of the pressing position, and the middle part 112 of the pressing foot 11 is provided with a cavity 111 and embedded with a flexible rotating ball 5. The screw ring 13 is embedded above the ball 5. The flexible pressing foot 11 can rotate 360 degrees around the fixed screw ring 133 and can be adjusted forward and backward to adapt to the edge part of the pressing frame. Referring to the accompanying drawings Figure 2 When the scanning sample is replaced, the pressing foot 11 is directly removed from the lead frame product 2 and placed laterally on the object table 3. After the next sample is placed, the length and angle of the pressing foot 11 are adjusted again for the next scanning.

[0054] As shown in the accompanying drawings Figure 3 The use method of the warping improvement device of the lead frame is as follows:

[0055] When the warped lead frame plastic packaging product is placed on the object table 3, the length and direction of the pressing foot 11 in the warping improvement device 1 on both sides are adjusted according to the size of the lead frame product 2. After adjustment, the front end of the pressing foot 11 is placed on the edge of the lead frame product 2 to ensure that the plastic packaging surface is not pressed. After adjustment, the warped lead frame is corrected and kept flat, and then ultrasonic scanning is performed.

[0056] Further, in a specific implementation process, before scanning, the lead frame product 2 is placed on the object table 3, and the two sides of the pressing foot 11 are fixedly arranged in the three circular holes (inner grooves) at the edge positions of the object table 3 by the fixing device 14. The number of circular holes (inner grooves) is 6, and the pressing foot 11 presses the left, middle and right parts of the lead frame on both sides, so that the frame can be kept at the same plane height during scanning, and the internal scanning result of the same scanning image will not appear different interfaces.

[0057] The embodiment is aimed at ultrasonic scanning of the LQFP44L-10x10-1.4 lead frame product 2 after plastic packaging. The length of the lead frame is 215.5mm, and the width is 45.7mm. The specific implementation steps are as follows:

[0058] Step 1: The main part of the warped lead frame product 2 is judged by the human eye. The product to be scanned is placed in the middle part of the object table 3 to ensure that it is completely submerged in the water medium. The air bubbles on the surface of the product are removed by using an ear cleaning ball.

[0059] Step 2: Adjust the pressing feet 11 in the two-sided warping improvement device 1 to the appropriate angle and length according to the frame size;

[0060] Step 3: After adjustment, press the two-sided pressing feet 11 to the edge portion of the lead frame product 2 without touching the surface of the plastic package;

[0061] Step 4: Move the ultrasonic scanning probe 4 to the middle position directly above the lead frame;

[0062] Step 5: Adjust the appropriate height and related parameters of the probe and the product, and perform a small range scan to further judge the scanning result;

[0063] Step 6: If the scanning result is normal, formal scanning of the entire product can be performed;

[0064] Step 7: After scanning is completed, determine whether the product has problems such as delamination, voids, etc. If no product problems are found, scan the next product according to the above steps.

[0065] In an embodiment for ultrasonic scanning of a QFN20L-3x3-0.75 plastic-encapsulated lead frame product 2, the lead frame product 2 has a length of 258 mm and a width of 78 mm, and the specific implementation steps are as follows:

[0066] Step 1: The human eye determines the main parts of the warping of the lead frame product 2, places the product to be scanned in the middle of the object table 3, ensures that it is completely submerged in the water medium, and uses an ear bulb to remove bubbles on the surface of the product.

[0067] Step 2: Adjust the pressing feet 11 in the two-sided warping improvement device 1 to the appropriate angle and length according to the frame size;

[0068] Step 3: After adjustment, press the two-sided pressing feet 11 to the edge portion of the lead frame product 2 without touching the surface of the plastic package;

[0069] Step 4: Move the ultrasonic scanning probe 4 to the middle position directly above the lead frame;

[0070] Step 5: Adjust the appropriate height and related parameters of the probe and the product, and perform a small range scan to further judge the scanning result;

[0071] Step 6: If the scanning result is normal, formal scanning of the entire product can be performed;

[0072] Step 7: After scanning is completed, determine whether the product has problems such as delamination, voids, etc. If no product problems are found, scan the next product according to the above steps.

[0073] The above merely illustrates the technical thought of the present application and cannot limit the protection scope of the present application, and any modification made on the basis of the technical scheme according to the technical thought of the present application falls within the protection scope of the present application.

Claims

1. A warpage improvement device of a lead frame, characterized by, The presser foot (11) and the embedded adjusting structure, which comprises a ball (5) and a spiral (13), the middle part (112) of the presser foot (11) has a hollow area, two sides of the periphery of the hollow area are respectively provided with cavities (111), the opening of the cavity (111) faces the hollow area, the ball (5) is embedded in the cavity (111), and part of the spiral (13) is embedded in the cavity (111) and above the ball (5).

2. The warpage improvement device of a lead frame according to claim 1, characterized by, The inside of the spiral (13) is provided with a screw (12), and the lower side of the spiral (13) is provided with a fixing device (14) for connecting the warping improvement device (1) and the object table (3).

3. The warpage improvement device of a lead frame according to claim 2, characterized by, The fixing device (14) comprises a spring (141) located below the spiral (13) and in contact with the spiral (13), the spring (141) is sleeved on the screw rod (142) of the screw (12), and the bottom of the screw (12) is provided with a bottom thread (143).

4. The warpage improvement device of a lead frame according to claim 3, characterized by, The head of the screw (12) is above the spiral (13), and the screw rod (142) of the screw (12) passes through the spiral (13) and the spring (141) in sequence.

5. The warpage improvement device of a lead frame according to claim 1, characterized by, The presser foot (11) comprises a force applying part, a first connecting part, a middle part (112), a second connecting part and a pressing part connected in sequence and integrally formed, the force applying part, the middle part (112) and the pressing part are in a stepped shape in sequence; the force applying part is suspended, and the pressing part is in contact with the lead frame product (2).

6. The warpage improvement device of a lead frame according to claim 5, wherein The force applying part, the middle part (112) and the pressing part are parallel to each other and gradually lower, and the first connecting part and the second connecting part are parallel to each other.

7. The warpage improvement device of a lead frame according to claim 1, characterized by, The balls (5) are arranged side by side in the cavities (111).

8. The warpage improvement device of a lead frame according to claim 1, characterized by, The depth of the cavity is equal to the diameter of the ball (5); the height of the cavity is greater than or equal to the sum of the diameter of the ball (5) and the thickness of the spiral (13).

9. The warpage improvement device of a lead frame according to claim 1, characterized by, The outer diameter of the spiral (13) is less than or equal to the length of the cavity (111), and the inner diameter of the spiral (13) is less than the distance between the two cavities (111).

10. The warpage improvement device of a lead frame according to claim 1, characterized by, The periphery of the cavity (111) is provided with a surplus as an edge part, the edge part comprises a top edge and a bottom edge distributed upward and downward, the bottom edge is provided with a baffle, the height of the baffle is not greater than the diameter of the ball (5) and not less than the radius of the ball (5).

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