Polishing device for extracting plastic packaging chip and polishing method of polishing device

Abstract

The invention provides a polishing device for extracting a plastic package chip and a polishing method of the polishing device, and relates to the technical field of polishing devices.The polishing device comprises polishing equipment, an empty groove is formed in the upper portion of the polishing equipment, and the empty groove is used for containing the polished plastic package chip; two fixing supports are fixedly installed above the positions, located on the two sides of the empty groove, of the grinding device, second motors are arranged on the two fixing supports, a side plate of the plastic package chip is inserted into a clamping frame, then the bottom of a fixing clamp is pressed downwards through elastic force of a first spring, at the moment, the side edge of the plastic package chip is clamped and fixed, and in the grinding process, the plastic package chip is fixed through the first motors. When the angle of the plastic package chip needs to be adjusted, the second motor is started, the second motor drives the plastic package chip to rotate, the plastic package chip can be adjusted to any angle, at the moment, polishing can be more convenient, meanwhile, automatic turnover can be achieved, the overall polishing efficiency is improved, and the polishing accuracy is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of grinding devices. More specifically, it particularly relates to a grinding device for extracting plastic-encapsulated chips and a grinding method thereof. Background Art

[0002] In the field of plastic-encapsulated chip grinding, existing technical methods have many limitations, restricting the grinding efficiency, precision, and the yield rate of chips.

[0003] Traditional plastic-encapsulated chip grinding equipment has serious deficiencies in chip clamping and angle adjustment. Common clamping methods are relatively single, making it difficult to firmly and accurately fix plastic-encapsulated chips of different specifications. During the grinding process, chip displacement is likely to occur, affecting the grinding precision. Moreover, there is a lack of a convenient angle adjustment mechanism. If the chip grinding angle needs to be changed, it often requires complex manual operations, which not only consume a large amount of time but also make it difficult to ensure the accuracy of angle adjustment and cannot achieve automatic turning over, resulting in low overall grinding efficiency.

[0004] The ability to adaptively adjust the grinding thickness is also a major shortcoming of the existing technology. Most equipment cannot automatically adjust the grinding position according to the actual thickness of the plastic-encapsulated chip. Operators can only manually control the grinding depth based on experience, which is very likely to cause over-grinding or under-grinding. Over-grinding will directly damage the chip and reduce the yield rate; under-grinding will not achieve the expected grinding effect and requires secondary processing, increasing the production cost and time cost.

[0005] The flexibility of the grinding method is poor. Traditional grinding equipment usually uses grinding discs with fixed angles and methods to grind chips, making it difficult to perform differential grinding according to the special requirements of different positions of plastic-encapsulated chips. Different parts of plastic-encapsulated chips may require different grinding forces, angles, or grinding methods, but existing equipment cannot meet such diverse needs, restricting the improvement of grinding quality.

[0006] The replacement of the grinding disc is also inconvenient. Existing grinding disc replacement structures are often complex in design and cumbersome in operation, requiring the use of multiple tools and taking a long time to complete the replacement. Moreover, the stability of the replaced grinding disc during the grinding process is insufficient, prone to shaking, affecting the consistency and precision of the grinding effect.

[0007] In summary, the existing plastic-encapsulated chip grinding technology has significant defects in chip clamping and angle adjustment, adaptive adjustment of grinding thickness, flexibility of grinding method, and replacement of grinding discs, and cannot meet the requirements of high-precision and high-efficiency grinding of plastic-encapsulated chips in the modern electronic manufacturing industry. Summary of the Invention

[0008] To solve the above technical problems, the present invention provides a grinding device and a grinding method for plastic encapsulated chip extraction to solve the above problems.

[0009] A grinding device and a grinding method for plastic encapsulated chip extraction, including a grinding device. An empty slot is opened above the grinding device, and the empty slot is used to place the plastic encapsulated chip to be ground. Above the grinding device on both sides of the empty slot, two fixed brackets are fixedly installed. A second motor is provided on each of the two fixed brackets. The output end of each second motor is fixedly installed with a clamping bracket. The two clamping brackets are used to clamp and fix the plastic encapsulated chip and at the same time for turning over the plastic encapsulated chip. Above the grinding device at the rear side of the empty slot, a fixed bracket is fixedly installed. A drive box that can move up and down is arranged inside the fixed bracket. A movable drive fixing bracket is installed on the side of the drive box. Below the drive fixing bracket, two grinding discs for grinding the plastic encapsulated chip are provided.

[0010] Preferably, fixing plates are slidably installed above the two fixed brackets. Chute grooves are opened on the surfaces of the two fixed brackets. The bottoms of the two fixing plates are installed in the chute grooves. A third drive motor is fixedly installed on the side wall of each fixing plate. The lead screw at the end of each third drive motor is threadedly connected to the side wall of the fixed bracket. A rubber pad is fixedly installed inside each clamping bracket. A fixed clamp is installed inside each clamping bracket above the rubber pad.

[0011] Preferably, a sliding rod is fixedly installed at the top of each fixed clamp, and each sliding rod slides inside the clamping bracket. A first spring is fixedly installed between the top of each sliding rod and the top of the clamping bracket. A rectangular sliding rail is penetrated and opened on the back of the fixed bracket. A first drive motor is fixedly installed on the top of the fixed bracket. The drive box is threadedly connected to the threaded rod at the end of the first drive motor. A connecting sliding rod and a second drive motor are fixedly installed on the back of the drive fixing bracket. The connecting sliding rod is located in the rectangular sliding rail opened on the fixed bracket. The threaded rod at the end of the second drive motor is threadedly connected to the drive box.

[0012] Preferably, a first motor is fixedly installed inside the driving fixing frame. The output shaft of the first motor is fixedly installed with an upper fixing cover. Two third motors facing opposite directions are fixedly installed on the inner wall of the upper fixing cover, and the ends of the two third motors are rotatably connected. A grinding frame is fixedly sleeved outside the output shaft of each third motor. A side card slot is opened below each grinding frame. A fixing pad is fixedly installed on the top of each grinding piece, and the fixing pad is installed in the side card slot opened in the grinding frame. A fixing bolt is movably installed between each grinding frame and the fixing pad. A third spring is fixedly installed between each fixing bolt and the surface of the grinding frame. Side support plates are fixedly installed at both ends of the upper fixing cover. A second spring is fixedly installed between the lower part of each side support plate and the surface of the grinding frame.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] In the present invention, the sliding rod at the top of the single-side fixing clip is pulled upward, and then the side plate of the plastic-sealed chip is inserted into the clamping frame. Subsequently, the first spring presses the bottom of the fixing clip downward through elastic force. At this time, the side of the plastic-sealed chip is clamped and fixed. During the grinding process, when the angle of the plastic-sealed chip needs to be adjusted, the second motor is started, and the second motor drives the plastic-sealed chip to rotate, and the plastic-sealed chip can be adjusted to any angle. At this time, it is more convenient to perform grinding, and at the same time, automatic turning can be achieved, improving the overall grinding efficiency and the accuracy of grinding.

[0015] In the present invention, during the grinding process, when the first driving motor is started, it can drive the driving box to move upward or downward. The driving box will drive the driving fixing frame on the side to move up and down. At the same time, the slide rod and the second driving motor connected to the back of the driving fixing frame both slide in the two rectangular slide rails. The up and down movement of the driving fixing frame can drive the two grinding pieces to move up and down, so as to perform adaptive adjustment according to the thickness of the plastic-sealed chip, improve the grinding ability, and avoid excessive grinding and damage to the chip.

[0016] In the present invention, when the first motor is started, it will drive the two grinding frames to rotate through the upper fixing cover. The two grinding frames drive the two grinding pieces to rotate. When the two grinding pieces contact the plastic-sealed chip, the plastic-sealed chip is ground. During the grinding process, when the two third motors are started, the two third motors drive the two grinding frames to rotate longitudinally through the output shafts. The two grinding frames drive the grinding pieces to rotate longitudinally, and the two second springs will pull the top of the grinding frames. At this time, due to the change of the angle of the two grinding pieces, the grinding ability of the plastic-sealed chip can be changed, so as to perform differential grinding on different positions of the plastic-sealed chip.

[0017] In the present invention, when different grinding discs need to be replaced during grinding, the fixing bolt can be pulled upward, and then the grinding disc can be slid horizontally to make the fixing pad leave the side card slot, and then the grinding disc can be replaced. The third spring between the fixing bolt and the grinding frame can play a spring pressing role to improve the stability of the grinding disc during grinding. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of the grinding device of the present invention;

[0019] Figure 2 is a schematic structural diagram of the clamping frame of the present invention;

[0020] Figure 3 is a schematic structural diagram of the fixing clip of the present invention;

[0021] Figure 4 is a schematic structural diagram of the fixing bracket of the present invention;

[0022] Figure 5 is a schematic structural diagram of the drive box of the present invention;

[0023] Figure 6 is a schematic structural diagram of the drive fixing frame of the present invention;

[0024] Figure 7 is a schematic structural diagram of the upper fixing cover of the present invention;

[0025] Figure 8 is a schematic structural diagram of the grinding disc of the present invention.

[0026] In the figure, the corresponding relationship between the component names and the drawing reference numbers is as follows: 1, grinding device; 11, empty slot; 12, fixing bracket; 13, first driving motor; 14, drive box; 15, rectangular slide rail; 17, drive fixing frame; 18, first electric motor; 19, second driving motor; 2, connecting slide bar; 21, fixing bracket; 22, fixing plate; 23, bottom chute; 24, third driving motor; 25, second electric motor; 26, clamping frame; 27, sliding bar; 28, rubber pad; 29, fixing clip; 3, first spring; 31, upper fixing cover; 33, third electric motor; 34, side support plate; 35, second spring; 36, grinding frame; 37, side card slot; 38, third spring; 39, fixing bolt; 4, grinding disc; 41, fixing pad. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following further describes in detail the embodiments of the present invention in conjunction with the drawings and embodiments. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0028] Please refer to Figures 1-8, the present invention provides a grinding device and a grinding method for extracting plastic-encapsulated chips, including a grinding device 1. An empty slot 11 is opened above the grinding device 1, and the empty slot 11 is used to place the plastic-encapsulated chips to be ground. Above the grinding device 1 on both sides of the empty slot 11, two fixed brackets 21 are fixedly installed. A second motor 25 is provided on each of the two fixed brackets 21. When the first driving motor 13 is started, it can drive the driving box 14 to move up or down. The driving box 14 will drive the driving fixing frame 17 on the side to move up and down. At the same time, the slide rod 2 and the second driving motor 19 connected to the back of the driving fixing frame 17 both slide within the two rectangular slide rails 15. The up and down movement of the driving fixing frame 17 can drive the two grinding discs 4 to move up and down, so that it can be adaptively adjusted according to the thickness of the plastic-encapsulated chips, improving the grinding ability. The first driving motor 13, the second driving motor 19, and the third driving motor 24 are all composed of a motor and a threaded rod, and the threaded rod is fixed to the output end of the motor. A clamping frame 26 is fixedly installed at the output end of each second motor 25. The two clamping frames 26 are used to clamp and fix the plastic-encapsulated chips, and at the same time are used for turning over the plastic-encapsulated chips. Above the grinding device 1 at the rear side of the empty slot 11, a fixed bracket 12 is fixedly installed. Inside the fixed bracket 12, there is a driving box 14 that can move up and down. A movable driving fixing frame 17 is installed on the side of the driving box 14. Below the driving fixing frame 17, there are two grinding discs 4 for grinding the plastic-encapsulated chips.

[0029] On the upper part of the two fixed brackets 21, fixing plates 22 are slidably installed. Chute grooves are opened on the surfaces of the two fixed brackets 21. The bottoms of the two fixing plates 22 are installed in the chute grooves. A third driving motor 24 is fixedly installed on the side wall of each fixing plate 22. Insert the two sides of the plastic-encapsulated chip into the two clamping frames 26. The fixed clamps 29 and rubber pads 28 inside the two clamping frames 26 clamp the plastic-encapsulated chip tightly. Then, start the first motor 18. The operation of the first motor 18 drives the upper fixed cover 31 to rotate. The rotation of the upper fixed cover 31 drives the two grinding frames 36 to rotate. The rotation of the two grinding frames 36 drives the two grinding discs 4 to rotate. The lead screws at the ends of each third driving motor 24 are threadedly connected to the side walls of the fixed brackets 21. A rubber pad 28 is fixedly installed inside each clamping frame 26. Inside each clamping frame 26 above the rubber pad 28, a fixed clamp 29 is installed.

[0030] A sliding rod 27 is fixedly installed at the top of each fixing clip 29, and each sliding rod 27 slides within the clamping frame 26. A first spring 3 is fixedly installed between the top of each sliding rod 27 and the top of the clamping frame 26. A rectangular sliding rail 15 is penetrated and opened on the back of the fixed bracket 12. A first driving motor 13 is fixedly installed at the top of the fixed bracket 12. The driving box 14 is threadedly connected to the threaded rod at the end of the first driving motor 13. A connecting sliding rod 2 and a second driving motor 19 are fixedly installed on the back of the driving fixed frame 17. The connecting sliding rod 2 is located within the rectangular sliding rail 15 opened on the fixed bracket 12. The threaded rod at the end of the second driving motor 19 is threadedly connected to the driving box 14.

[0031] A first motor 18 is fixedly installed inside the driving fixed frame 17. An output shaft of the first motor 18 is fixedly installed with an upper fixing cover 31. Two third motors 33 facing opposite directions are fixedly installed on the inner wall of the upper fixing cover 31, and the ends of the two third motors 33 are rotatably connected. A grinding frame 36 is fixedly sleeved outside the output shaft of each third motor 33. A side card slot 37 is opened below each grinding frame 36. A fixing pad 41 is fixedly installed at the top of each grinding piece 4, and the fixing pad 41 is installed within the side card slot 37 opened on the grinding frame 36. A fixing bolt 39 is movably installed between each grinding frame 36 and the fixing pad 41. A third spring 38 is fixedly installed between each fixing bolt 39 and the surface of the grinding frame 36. Side support plates 34 are fixedly installed at both ends of the upper fixing cover 31. A second spring 35 is fixedly installed between the lower part of each side support plate 34 and the surface of the grinding frame 36.

[0032] Working principle:

[0033] In the first step, when grinding the plastic - encapsulated chip, insert both sides of the plastic - encapsulated chip into the two clamping frames 26. The fixing clips 29 and rubber pads 28 inside the two clamping frames 26 clamp the plastic - encapsulated chip. Then start the first motor 18. The operation of the first motor 18 drives the upper fixing cover 31 to rotate. The rotation of the upper fixing cover 31 drives the two grinding frames 36 to rotate. The rotation of the two grinding frames 36 drives the two grinding pieces 4 to rotate. The two grinding pieces 4 rotate to grind the surface of the plastic - encapsulated chip, removing the solder balls, substrates, and adhesives. After the grinding pieces 4 finish grinding, the grinding pieces 4 can be replaced with sandpapers and polishing cloths of different particle sizes for grinding and polishing. In principle, use a grinding and polishing process that is first coarse then fine, first fast then slow until the bare core exposes the silicon crystal back. Use a cotton swab and alcohol to soften and remove the adhesive on the crystal back;

[0034] Then reverse the grinding direction and continue to grind using the same method of the grinding device 1 to remove the plastic - encapsulated resin surface until the bare - core solder joints are exposed. Use sandpapers and polishing cloths of different particle sizes to remove the plastic - encapsulated resin. In principle, use a grinding and polishing process that is first coarse then fine, first fast then slow until the solder joints on the bare core are exposed;

[0035] Use a laser device to cut off the excess encapsulant around the bare die. During the process, the laser does not touch the bare die.

[0036] Finally, soak it in fuming nitric acid at 90 °C for 30 s. The residual epoxy encapsulant is quickly removed, and the bare die will not be corroded by the chemical solution in a short time. Then put the bare die into an ultrasonic device with acetone or alcohol solution for cleaning, and blow it dry after completion to finish. The above operations and steps require the corresponding personnel to have basic grinding and polishing skills and the ability to use relevant equipment.

[0037] In the second step, when using two clamping frames 26 to fix the encapsulated chip, pull the sliding rod 27 at the top of the single-side fixing clip 29 upward. Then insert the side plate of the encapsulated chip into the clamping frame 26. Subsequently, the first spring 3 presses the bottom of the fixing clip 29 downward by its elastic force. At this time, the side of the encapsulated chip is clamped and fixed. During the grinding process, when the angle of the encapsulated chip needs to be adjusted, start the second motor 25. The second motor 25 drives the encapsulated chip to rotate, and the encapsulated chip can be adjusted to any angle. At this time, it is more convenient to perform grinding, and at the same time, it can be automatically turned over, improving the overall grinding efficiency and the accuracy of grinding.

[0038] Since different encapsulated chips have different sizes, the user can start the third driving motor 24. The third driving motor 24 drives the fixing plate 22 to move through the threaded rod at its end. The movement of the fixing plate 22 drives the second motor 25 to move. The movement of the second motor 25 drives the clamping frame 26 to move. The movement of the two clamping frames 26 can adjust and install encapsulated chips of different sizes, so as to meet the grinding of different encapsulated chips.

[0039] In the third step, during the grinding process, starting the first driving motor 13 can drive the driving box 14 to move up or down. The driving box 14 drives the driving fixing frame 17 on the side to move up and down. At the same time, the slide rod 2 and the second driving motor 19 connected to the back of the driving fixing frame 17 both slide in the two rectangular slide rails 15. The up and down movement of the driving fixing frame 17 can drive the two grinding discs 4 to move up and down, so as to perform adaptive adjustment according to the thickness of the encapsulated chip, improving the grinding ability and avoiding over-grinding and damaging the chip.

[0040] When the second driving motor 19 is started, it cooperates with the driving box 14 to drive the driving fixing frame 17 to move back and forth. The back and forth movement of the driving fixing frame 17 can adjust the grinding position, so as to ensure the grinding of different encapsulated chips and further improve the grinding ability.

[0041] When the first motor 18 starts, it drives the two grinding frames 36 to rotate through the upper fixed cover 31. The rotation of the two grinding frames 36 drives the two grinding discs 4 to rotate. When the two grinding discs 4 come into contact with the plastic-encapsulated chip, the plastic-encapsulated chip is ground. During the grinding process, two third motors 33 are started. The two third motors 33 drive the two grinding frames 36 to rotate longitudinally through the output shafts. The two grinding frames 36 drive the grinding discs 4 to rotate longitudinally. And two second springs 35 will pull the tops of the grinding frames 36. At this time, due to the change in angle, the two grinding discs 4 can change the grinding ability for the plastic-encapsulated chip, so that different parts of the plastic-encapsulated chip can be ground differently;

[0042] When different grinding discs 4 need to be replaced during grinding, the fixing bolts 39 can be pulled upward, and then the grinding discs 4 are slid horizontally to make the fixing pads 41 leave the side slots 37. Then the grinding discs 4 are replaced. The third springs 38 between the fixing bolts 39 and the grinding frames 36 can play a spring pressing role to improve the stability of the grinding discs 4 during grinding.

[0043] The embodiments of the present invention are given for purposes of illustration and description, and are not exhaustive or limit the invention to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are chosen and described in order to better explain the principles of the invention and its practical application, and to enable those of ordinary skill in the art to understand the invention and design various embodiments with various modifications suitable for specific purposes.

Claims

1. A grinding device for extracting plastic-encapsulated chips, comprising a grinding device (1), characterized in that: An empty slot (11) is provided above the polishing device (1), and the empty slot (11) is used to place the plastic-encapsulated chip to be polished. Two fixed brackets (21) are fixedly installed above the polishing device (1) on both sides of the empty slot (11), and a second motor (25) is provided on each of the two fixed brackets (21). A clamping frame (26) is fixedly installed at the output end of each second motor (25). The two clamping frames (26) are used to clamp and fix the plastic-encapsulated chip and to turn over the plastic-encapsulated chip. A fixed bracket (12) is fixedly installed above the polishing device (1) at the rear side of the empty slot (11), and a drive box (14) that can move up and down is provided inside the fixed bracket (12). A movable drive fixed bracket (17) is installed on the side of the drive box (14), and two polishing plates (4) for polishing the plastic-encapsulated chip are provided below the drive fixed bracket (17).

2. A grinding device for extracting plastic-encapsulated chips as claimed in claim 1, characterized in that: A fixing plate (22) is slidably mounted above the two fixing brackets (21), a sliding groove is provided on the surface of the two fixing brackets (21), and the bottoms of the two fixing plates (22) are mounted in the sliding groove.

3. A grinding device for extracting plastic-encapsulated chips as claimed in claim 2, characterized in that: A third drive motor (24) is fixedly mounted on the side wall of each of the fixed plates (22), and a screw rod at the end of each of the third drive motors (24) is threadedly connected to the side wall of the fixed bracket (21).

4. A grinding device for extracting plastic-encapsulated chips as claimed in claim 1, characterized in that: A rubber pad (28) is fixedly installed inside each clamping frame (26), and a fixing clamp (29) is installed inside each clamping frame (26) located above the rubber pad (28).

5. A grinding device for extracting plastic-encapsulated chips as claimed in claim 4, characterized in that: A sliding rod (27) is fixedly mounted on the top of each fixing clamp (29), and each sliding rod (27) slides in the clamping frame (26), and a first spring (3) is fixedly mounted between the top of each sliding rod (27) and the top of the clamping frame (26).

6. A grinding device for extracting plastic-encapsulated chips as claimed in claim 1, characterized in that: A rectangular slide rail (15) is provided through the back of the fixed bracket (12), a first drive motor (13) is fixedly mounted on the top of the fixed bracket (12), and the drive box (14) is threadedly connected to a threaded rod at the end of the first drive motor (13).

7. A grinding device for extracting plastic-encapsulated chips as claimed in claim 1, characterized in that: A connecting slide bar (2) and a second driving motor (19) are fixedly mounted on the back of the driving fixed frame (17); the connecting slide bar (2) is located in a rectangular slide rail (15) provided on the fixed bracket (12); a threaded rod at the end of the second driving motor (19) is threadedly connected to a driving box (14); a first motor (18) is fixedly mounted inside the driving fixed frame (17); an upper fixed cover (31) is fixedly mounted on the output shaft of the first motor (18); two third motors (33) facing opposite directions are fixedly mounted on the inner wall of the upper fixed cover (31), and the ends of the two third motors (33) are rotatably connected.

8. A grinding device for extracting plastic-encapsulated chips as claimed in claim 1, characterized in that: A grinding frame (36) is fixedly sleeved outside the output shaft of each third motor (33), a side slot (37) is opened below each grinding frame (36), a fixed pad (41) is fixedly installed on the top of each grinding sheet (4), and the fixed pad (41) is installed in the side slot (37) opened on the grinding frame (36).

9. A grinding device for extracting plastic-encapsulated chips as claimed in claim 1, characterized in that: A fixing bolt (39) is movably installed between each of the grinding frames (36) and the fixing pad (41), a third spring (38) is fixedly installed between each of the fixing bolts (39) and the surface of the grinding frame (36), side support plates (34) are fixedly installed at both side ends of the upper fixing cover (31), and a second spring (35) is fixedly installed between the bottom of each of the side support plates (34) and the surface of the grinding frame (36).

10. A polishing method for extracting plastic-encapsulated chips, characterized in that: S1: When polishing the plastic-encapsulated chip, insert both sides of the plastic-encapsulated chip into two clamping frames 26, and the fixing clips (29) and rubber pads (28) inside the two clamping frames (26) clamp the plastic-encapsulated chip. Then, start the first motor (18), and the operation of the first motor (18) drives the upper fixed cover (31) to rotate. The rotation of the upper fixed cover (31) drives the two polishing frames (36) to rotate. The rotation of the two polishing frames (36) drives the two polishing sheets (4) to rotate. The two polishing sheets (4) rotate to polish the surface of the plastic-encapsulated chip to remove solder balls, substrates, and adhesives. After the polishing sheets (4) are polished, the polishing sheets (4) can be replaced with sandpaper and polishing cloths of different coarse and fine particle sizes for grinding and polishing. In principle, a grinding and polishing process of coarse first, fine second, fast first, and slow last is used until the bare core exposes the silicon crystal back. A cotton swab and alcohol method is used to soften and remove the adhesive on the crystal back. S2: Reverse the grinding direction and continue to grind using the same method as grinding device 1 to remove the plastic resin surface until the bare core solder joints are exposed. Use sandpaper and polishing cloth of different coarse and fine particle sizes to remove the plastic resin. In principle, use a grinding and polishing process of first coarse then fine, first fast then slow, until the solder joints on the bare core are exposed; S3: Use laser equipment to remove excess plastic packaging material around the bare die. The laser does not touch the bare die during the process. S4: Finally, use 90℃ fuming nitric acid to soak for 30S, the residual epoxy resin plastic packaging material is quickly removed, and the bare die will not be corroded by the short-term chemical solution. Put the bare die into an ultrasonic device with acetone or alcohol solution for cleaning, and blow dry after completion. The above operations and steps require the corresponding personnel to have basic grinding and polishing and related equipment usage capabilities.

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