Overflow glue cleaning method and device

Abstract

The invention provides an excessive glue cleaning method and device, and belongs to the technical field of semiconductors, and the method is applied to a target semiconductor device with excessive glue, and comprises the steps: S1, carrying out the pre-cooling processing of the target semiconductor device; s2, performing dry ice spraying treatment on the overflowed glue of the pre-cooled target semiconductor device so as to remove the overflowed glue; and S3, performing electric contact with the target semiconductor device through the grounding assembly so as to release electrostatic charges generated by dry ice spraying. The method has the beneficial effects that a dry ice spraying mode is adopted, so that overflowing glue is stripped after generating microcracks, and the dry ice sublimates without secondary waste and chemical residues; pre-cooling treatment is performed before dry ice is sprayed, so that the toughness of excessive glue is reduced, and efficient cleaning is realized under low spraying kinetic energy; the thermal stress problem is avoided through physical cold treatment; in addition, electrostatic charges are released through the grounding assembly, potential risks and secondary pollution of static electricity to the power module are avoided, and efficient, lossless and pollution-free excessive glue cleaning is achieved.

Description

A method and apparatus for cleaning up excess adhesive Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method and apparatus for cleaning excess adhesive. Background Technology

[0002] Power modules are core components of power electronic devices. Common power modules, such as Insulated Gate Bipolar Transistor (IGBT) modules and Silicon Carbide (SiC) modules, are widely used in many fields, including new energy vehicles, smart grids, and industrial automation. To improve the insulation, mechanical strength, and weather resistance of power modules, epoxy resin is commonly used for molding and encapsulation in the industry. However, during the molding and encapsulation process, epoxy resin inevitably overflows onto the metal heat sink at the bottom of the module, which is usually made of copper.

[0003] To ensure the heat dissipation performance of power modules, the cleanliness and flatness of the metal heat sink surface are crucial. Existing methods for cleaning excess adhesive on power module heat sink surfaces mainly include mechanical scraping, chemical solvent methods, and laser ablation. Mechanical scraping, using blades or other tools to remove excess adhesive, can easily scratch the soft metal heat sink surface, leading to decreased flatness, increased thermal resistance, and reduced heat dissipation efficiency; in severe cases, it can even cause the module to overheat and fail. Chemical solvent methods use strong solvents such as dichloromethane and N-methylpyrrolidone for soaking or wiping, posing a risk of chemical residue, corrosion of the metal, or contamination of the module's interior, and are also harmful to operator health, making them environmentally unfriendly. Laser ablation involves expensive equipment, and the thermal effect of the laser can cause thermal damage to the chips, bonding wires, or packaging materials inside the module, altering their performance, posing a high risk.

[0004] Dry ice blasting technology, as an environmentally friendly cleaning method, is known to be used in mold cleaning, surface decontamination, and other fields. However, applying it to the cleaning of excess adhesive on the heat dissipation surfaces of precision, high-value power modules presents a unique technical challenge: how to efficiently remove high-hardness epoxy resin while ensuring zero damage, zero residue, and no thermal stress.

[0005] Furthermore, the applicant discovered that dry ice particles generate significant static charge during high-speed impact and sublimation. Since the metal heat sink surface and fixtures of the power module are typically insulated, this charge cannot dissipate in time and accumulates on the module, attracting dust and causing secondary pollution. More seriously, the accumulated high-voltage static electricity can cause potential electrical stress damage to the delicate semiconductor chips inside the module, severely impacting product reliability and yield. Summary of the Invention

[0006] To address the above technical problems, the present invention provides a method for cleaning excess adhesive; on the other hand, it also provides an apparatus for cleaning excess adhesive.

[0007] The technical problem solved by this invention can be achieved by the following technical solutions:

[0008] An adhesive overflow removal method, applied to a target semiconductor device with adhesive overflow, the method comprising:

[0009] Step S1: Perform a pre-cooling treatment on the target semiconductor device;

[0010] Step S2: Dry ice blasting is performed on the pre-cooled target semiconductor device to remove the excess adhesive;

[0011] Step S3: Make electrical contact with the target semiconductor device through the grounding component to release the static charge generated by dry ice spraying.

[0012] Preferably, step S1 includes:

[0013] The target semiconductor device is placed in a preset temperature environment to pre-cool the excess adhesive; wherein the preset temperature environment is -10℃ to 10℃.

[0014] Preferably, in step S2, the dry ice sprayed in the dry ice spraying process is a second type of dry ice particles.

[0015] Preferably, the particle size of the second dry ice particles is 0.1 mm to 2.0 mm; and / or

[0016] The second dry ice particle is formed by grinding the first dry ice particle. The first dry ice particle is cylindrical, with a nominal diameter of 3mm to 5mm and a length of less than 5cm.

[0017] Preferably, the dry ice blasting process satisfies any one or more of the following blasting conditions:

[0018] The dry ice is sprayed at a preset pressure, which is 0.1 MPa to 2.0 MPa.

[0019] The dry ice injection flow rate is 0.1 L / min to 1 L / min;

[0020] The dry ice is sprayed from a distance of 10mm to 200mm.

[0021] The dry ice is sprayed at an angle of 45° to 90° relative to the plane of the target semiconductor device;

[0022] The dry ice blasting process is carried out under preset environmental conditions, which include: an ambient temperature of 18℃~28℃ and an ambient humidity of 30%RH~60%RH.

[0023] The dry ice spraying process uses a spray gun, which moves along a preset path and sprays dry ice at a preset speed, the preset speed being 2mm / s to 150mm / s.

[0024] Preferably, step S2 further includes: simultaneously with or after the dry ice blasting process, applying negative pressure to adsorb the excess adhesive that has been removed from the target semiconductor device.

[0025] On the other hand, an adhesive overflow cleaning device is also provided for implementing the adhesive overflow cleaning method described above. The device includes:

[0026] Pre-cooling assembly for pre-cooling target semiconductor devices with excess adhesive;

[0027] The device body is equipped with an XYZ axis slide module, and the device body is connected to a grounding wire;

[0028] A clamp is disposed on the device body and is used to load at least one pre-cooled target semiconductor device;

[0029] A spraying assembly, which is disposed on the XYZ axis slide module, is used to perform dry ice spraying on the excess adhesive of the target semiconductor device after pre-cooling treatment in order to remove the excess adhesive.

[0030] A grounding component forms electrical contact with the target semiconductor device and the clamp to release the static charge generated by dry ice spraying through the clamp, the device body, and the grounding wire.

[0031] Preferably, the clamp includes:

[0032] The clamp body has at least one clamp positioning slot, at least one module positioning slot and a corresponding module spring slot. The clamp positioning slot is located on the edge of the clamp body and cooperates with the spring block on the device body to fix the clamp on the device body.

[0033] The module positioning slot is used to load the target semiconductor device, and the module spring slot abuts against the target semiconductor device loaded in the module positioning slot to fix the target semiconductor device.

[0034] At least one metal pressure bar, with both ends of each metal pressure bar respectively mounted on the clamp body via pressure bar fixing blocks, and at least one grounding component sleeved on each metal pressure bar;

[0035] Each of the metal pressure bars is fitted with a V-shaped spring. Under the elastic force of the V-shaped spring, the grounding component on the metal pressure bar forms an electrical contact with the target semiconductor device, and flips under the action of external force and is fixed by the pressure bar flipping fixing hook, which is set on the clamp body.

[0036] Preferably, the grounding component includes an elastic conductor, which is any one or a combination of two of conductive sponge and conductive rubber.

[0037] Preferably, it further includes:

[0038] The negative pressure adsorption component is disposed inside the main body of the device and located below the clamp.

[0039] The advantages or beneficial effects of the technical solution of this invention are as follows:

[0040] This invention employs dry ice blasting to create micro-cracks in the excess adhesive before peeling it off, and the dry ice sublimates without causing secondary waste or chemical residue. Pre-cooling before dry ice blasting reduces the toughness of the excess adhesive, enabling efficient cleaning at low blasting energy. Physical cooling avoids the thermal stress problems caused by conventional methods such as laser or high-temperature baking. Furthermore, grounding components promptly release the static charge generated during dry ice blasting, fundamentally eliminating the potential breakdown risk and secondary contamination of power modules due to static electricity, achieving efficient, non-destructive, and pollution-free excess adhesive cleaning. Attached Figure Description

[0041] Figure 1 is a flowchart illustrating the adhesive overflow cleaning method in a preferred embodiment of the present invention.

[0042] Figure 2 is a schematic diagram of the adhesive overflow cleaning device in a preferred embodiment of the present invention;

[0043] Figure 3 is a schematic diagram of the principle of dry ice spray cleaning of excess adhesive in a preferred embodiment of the present invention;

[0044] Figure 4 is a schematic diagram of the fixture in a preferred embodiment of the present invention;

[0045] Figure 5 is a schematic diagram of the fixture in a preferred embodiment of the present invention;

[0046] Figure 6 is an enlarged view of the module spring slot in a preferred embodiment of the present invention.

[0047] Explanation of reference numerals in the attached figures:

[0048] 100. Target semiconductor device; 200. Excess adhesive;

[0049] 1. Device body; 11. Grounding wire; 12. First rotating shaft; 13. Spring pressure block; 14. Flow meter; 15. Fixture fixing seat; 2. XYZ axis slide module; 21. First guide rail; 22. Second slider guide rail; 23. Third slider; 24. Second rotating shaft; 25. Fourth slide rail; 26. Fifth slider; 3. Fixture; 30. Fixture body; 31. Fixture positioning slot; 32. Module positioning slot; 33. Module spring slot; 34. Metal pressure rod; 35. Pressure rod fixing block; 36. Pressure rod flipping fixing hook; 37. V-shaped spring; 4. Spray assembly; 41. Dry ice hopper; 42. Grinding component; 43. Motor; 44. Dry ice flow control component; 45. Compressed air control component; 46. Spray gun; 5. Negative pressure adsorption assembly; 51. Fan; 52. Dust collection box; 6. Grounding assembly. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0052] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0053] In a preferred embodiment of the present invention, based on the above-mentioned problems existing in the prior art, an adhesive overflow cleaning method is provided, applied to a target semiconductor device with adhesive overflow, as shown in FIG1, the method comprising:

[0054] Step S1: Perform a pre-cooling process on the target semiconductor device;

[0055] Step S2: Dry ice blasting is performed on the pre-cooled target semiconductor device to remove the excess adhesive.

[0056] Step S3: Make electrical contact with the target semiconductor device through the grounding component to release the static charge generated by dry ice spraying.

[0057] Specifically, traditional adhesive removal methods, such as mechanical scraping, chemical etching, and laser removal, all suffer from the drawbacks of damaging the substrate surface or contaminating the module. In this embodiment, dry ice blasting is used. By utilizing the combined effect of the kinetic impact effect and the low-temperature embrittlement effect of dry ice, when the high-speed blasted dry ice particles impact the adhesive, they cause micro-cracks in the adhesive, which then peels off, making it easier to clean up the peeled adhesive debris. This achieves selective removal of the adhesive, effectively removing hard and brittle adhesive without causing any scratches or plastic deformation to the target semiconductor device itself, especially the metal heat sink surface, perfectly maintaining the original flatness of the metal heat sink surface of the target semiconductor device.

[0058] Meanwhile, pre-cooling the target semiconductor device before dry ice blasting to remove excess adhesive can reduce the toughness of the epoxy resin and change its physical properties, thereby enabling efficient cleaning with lower blasting kinetic energy.

[0059] Furthermore, during or after spraying, the dry ice sublimates into carbon dioxide gas, producing no secondary waste or chemical residues. This ensures the long-term reliability of the target semiconductor device, is pollution-free, and environmentally friendly. The entire cleaning process is a physical cold treatment, avoiding the thermal stress problems caused by lasers or high-temperature baking, thus preventing damage to the sensitive semiconductor chips and interconnect structures inside the device and eliminating the risk of thermal stress.

[0060] Finally, an electrical contact is established between the grounding component and the target semiconductor device to release the static charge generated during dry ice blasting. Static charge is inevitably generated during dry ice blasting to remove excess adhesive. If this static charge is not released in time, it can pose a potential risk of breakdown and secondary contamination to the power module. This invention, through its unique grounding component, can promptly release the static charge generated during dry ice blasting, fundamentally avoiding the potential risk of breakdown and secondary contamination to the power module caused by static electricity, thus ensuring product reliability.

[0061] The glue overflow cleaning method of this invention has good integration capabilities, is easy to combine with visual recognition and robotics, and can achieve efficient and fully automated production, significantly improving production efficiency and product yield. Furthermore, dry ice particles have excellent cleaning capabilities, able to reach deep into every corner of complex geometries, effectively cleaning glue overflow—something difficult to achieve with traditional methods.

[0062] In this embodiment, the target semiconductor device can be a power module, such as an IGBT power module or a SiC power module, or other devices or equipment that require adhesive overflow cleaning.

[0063] In this embodiment, "excess adhesive" refers to the portion of molding compound that overflows onto a specific location on the target semiconductor device during the packaging process. This molding compound can be epoxy resin, but other types of molding compounds are also possible. The specific location is the metal heat sink surface of the power module, but it can also be any other location requiring adhesive removal. Using the method of this invention during the power module packaging process, excess adhesive on the metal heat sink surface of the power module can be removed efficiently, without damage, and without contamination.

[0064] Furthermore, step S1 includes:

[0065] The target semiconductor device is placed in a preset temperature environment to pre-cool the excess adhesive; wherein the preset temperature environment is -10℃ to 10℃.

[0066] Specifically, in this embodiment, the power module is pre-cooled before dry ice blasting to remove excess adhesive, reducing the toughness of the epoxy resin. Compared to using dry ice blasting alone to remove excess adhesive, this embodiment employs a combined pre-cooling and dry ice blasting method. The low-temperature embrittlement effect of the pre-cooled adhesive, combined with the kinetic impact effect of dry ice and its own low-temperature embrittlement effect, allows for efficient cleaning at lower blasting kinetic energy.

[0067] The specific operation procedure for pre-cooling is as follows: First, multiple epoxy-encapsulated target semiconductor devices are placed in batches in an industrial cold storage cabinet to lower the epoxy resin temperature below its brittle-ductile transition zone. The temperature of this industrial cold storage cabinet can be set within the range of -10℃ to 10℃. If the pre-cooling temperature is below -10℃, the temperature is too low, which will cause some epoxy resins to become excessively brittle and crack, which is detrimental to precision components; if the pre-cooling temperature exceeds 10℃, the temperature is too high, the embrittlement effect is poor, and cleaning is difficult. As an example, and not a limitation, the pre-cooling temperature can be specifically set to -10℃, -9℃, -8℃, -7℃, -6℃, -5℃, -4℃, -3℃, -2℃, -1℃, 0℃, 1℃, 2℃, 3℃, 4℃, 5℃, 6℃, 7℃, 8℃, 9℃, and 10℃. Within this temperature range, the toughness of the epoxy resin can be effectively reduced without adversely affecting other performance characteristics of the power module.

[0068] After placing the power module in the refrigerator, let it stand for 5-60 minutes. Too short a standing time will not allow for sufficient cooling, while too long a time will affect efficiency. Different pre-cooling times should be used depending on the module's specifications and size. The goal is to pre-cool the module to the target temperature in the shortest possible time to ensure that the excess adhesive is adequately pre-cooled. During the subsequent dry ice blasting cleaning process, the relatively low blasting energy is sufficient to create micro-cracks in the epoxy resin and cause it to peel off, thus achieving efficient cleaning.

[0069] Furthermore, in step S2, the dry ice sprayed in the dry ice blasting process is a second dry ice particle; the particle size of the second dry ice particle is 0.1 mm to 2.0 mm.

[0070] The second dry ice particle is formed by grinding the first dry ice particle. The first dry ice particle is cylindrical, with a nominal diameter of 3mm to 5mm and a length of less than 5cm.

[0071] Specifically, in this embodiment, the dry ice material is selected from high-density cylindrical first dry ice particles. Columnar dry ice has a wide range of industrial applications and is readily available on the market.

[0072] Considering that some ice materials have excessively small diameters and lengths, their evaporation rate is too fast, which is not conducive to long-term storage; conversely, if the diameter and length are too large, it will increase the difficulty of grinding and crushing, place higher demands on the performance of the grinding equipment, and easily damage the equipment during the grinding process. In this embodiment, the nominal diameter of the first dry ice particle is 3-5 mm, and the length is less than 5 cm.

[0073] The large dry ice particles are ground into finer second dry ice particles. The particle size of the second dry ice particles is approximately 0.1 mm to 2.0 mm. When the particle size is less than 0.1 mm, the dry ice particles lack momentum, leading to a significant reduction in cleaning efficiency. While particles larger than 2.0 mm are less likely to scratch the surface, they can cause excessive impact, posing a risk of leaving microscopic pits on the surface. More preferably, the particle size is controlled between 0.1 and 1.5 mm. Dry ice particles of this size have higher density and momentum, providing more effective impact energy during the cleaning process.

[0074] Furthermore, the dry ice blasting process satisfies any one or more of the following blasting conditions:

[0075] Dry ice is sprayed at a preset pressure, which is 0.1 MPa to 2.0 MPa.

[0076] The dry ice injection flow rate is 0.1 L / min to 1 L / min;

[0077] The spray distance of dry ice is 10mm to 200mm;

[0078] The dry ice is sprayed at an angle of 45° to 90° relative to the plane of the target semiconductor device;

[0079] Dry ice blasting is carried out under preset environmental conditions, including: ambient temperature of 18℃~28℃ and ambient humidity of 30%RH~60%RH.

[0080] Dry ice blasting is performed using a spray gun, which moves along a preset path at a preset speed and sprays dry ice. The preset speed is 2 mm / s to 150 mm / s.

[0081] Specifically, in this embodiment, the target semiconductor device, after being encapsulated and pre-cooled and cured, is fixedly mounted on the fixture of the adhesive overflow cleaning device, with the metal heat dissipation surface of the device facing upwards; the process parameters for dry ice blasting are set according to the different encapsulation materials used in different modules; the dry ice blasting machine is started, and the adhesive overflow area on the metal heat dissipation surface of the target semiconductor device is scanned and blasted cleaned according to the preset path and parameters.

[0082] The process parameters for dry ice blasting are as follows:

[0083] The spraying pressure is 0.1MPa to 2.0MPa. If the spraying pressure is lower than 0.1MPa, the epoxy adhesive cannot be effectively broken and peeled off due to the low pressure; while if the spraying pressure is higher than 2.0MPa, although the cleaning efficiency can be improved, the cost will increase and the economy will be reduced. At the same time, it will leave very slight impact marks on the surface of the metal material.

[0084] The spray flow rate is 0.1L / min to 1L / min. If the spray flow rate is less than 0.1L / min, it is difficult to effectively break and peel off the epoxy adhesive; if the spray flow rate exceeds 1L / min, although the efficiency can be improved, the economic efficiency will be reduced, and excessive flow rate is prone to generating water vapor, which will cause the module to become wet and oxidized.

[0085] The spraying distance is 10mm to 200mm, and more preferably 10mm to 100mm. If the spraying distance is less than 10mm, the impact area will be too small and the flow field will be unstable; conversely, if the distance is too far, the velocity of the dry ice particles will decrease and the kinetic energy will be insufficient, and the jet stream will diverge, resulting in a sharp drop in cleaning efficiency.

[0086] The spray angle relative to the heat dissipation plane of the target semiconductor device is 45° to 90°. Energy transfer efficiency is highest when spraying perpendicularly at a 90° angle. For semiconductor devices with complex structures (such as deep trenches or protrusions), adjusting the tilt angle (45° to 90°) appropriately ensures that the sidewalls are cleaned, avoiding collisions.

[0087] The moving speed of the spray gun is 2mm / s to 150mm / s, and more preferably, the preset speed is 2mm / s to 20mm / s. If the moving speed is too slow, the energy input per unit area is too high, which is not only uneconomical, but also leads to local overcooling; conversely, if the moving speed is too fast, a single impact cannot effectively embrittle and peel off the adhesive layer, requiring multiple cleaning cycles.

[0088] The ambient temperature should be between 18℃ and 28℃. If the ambient temperature is too high, it will accelerate the evaporation and loss of dry ice, easily generating water vapor, which will cause the module to become wet and oxidize; conversely, if the ambient temperature is below 18℃, it will increase energy consumption costs.

[0089] The ambient humidity should be between 30% and 60% RH. If the ambient humidity is too high, condensation is likely to occur during processing, causing the modules to become wet and oxidized; conversely, if the ambient humidity is too low, energy consumption costs will also increase.

[0090] Extensive experimental verification has shown that the above parameter range is an optimized range applicable to the vast majority of power modules on the market. Those skilled in the art can make fine adjustments within the disclosed parameter range to adapt to different module models and different types of epoxy resins; all such adjustments fall within the protection scope of this invention.

[0091] After the large dry ice particles are broken up by the grinding components, they are accelerated by compressed air and impact the epoxy adhesive layer that has overflowed onto the metal heat sink at high speed. Utilizing the synergistic effect of the kinetic impact of the dry ice and the low-temperature embrittlement effect, microcracks are created in the overflow adhesive, thereby achieving peeling.

[0092] By precisely controlling the above-mentioned process parameters, this invention successfully applies dry ice blasting technology to the high-precision manufacturing field of power modules, solving the long-standing problem of excess adhesive cleaning and bringing about objective technical and economic benefits.

[0093] Furthermore, step S2 also includes: applying negative pressure to adsorb the excess adhesive from the target semiconductor device during or after the dry ice blasting process.

[0094] Specifically, if the excess adhesive debris removed during the cleaning process is not cleaned up in time, it will re-adhere to the surface of the power module, affecting heat dissipation and electrical performance. At the same time, although the carbon dioxide gas produced by dry ice sublimation is harmless in itself, in a closed working environment, a large accumulation of carbon dioxide can affect the health of operators and may also interfere with subsequent testing work.

[0095] In this embodiment, during or after the dry ice blasting process, the excess adhesive residue and carbon dioxide gas are removed. Specifically, a negative pressure adsorption assembly is used to simultaneously remove the removed epoxy adhesive debris and sublimated carbon dioxide gas.

[0096] After cleaning, the metal heat sink surface of the power module undergoes visual inspection and flatness measurement. This process involves both macroscopic observation and microscopic testing. During macroscopic observation, the power module is placed under lighting conditions and observed visually. Areas where excess adhesive was present have been thoroughly cleaned, and the metal substrate has regained its original metallic luster. Touching the heat sink surface reveals a smooth and flat surface without any roughness.

[0097] During the microscopic inspection phase, a microscope was used to observe the boundary between the cleaned area and the original metal area at 150x magnification. The boundary was clearly visible, and there were no visible scratches or pits within the cleaned area. Simultaneously, the surface roughness (Ra) of the copper substrate was measured, and the Ra value deviation between the cleaned area and the original uncoated area was less than 0.05 μm. Within this measurement error range, the cleaning process achieved true zero damage to the substrate.

[0098] Only after the appearance inspection and flatness measurement meet the standard requirements can the power module enter the next production stage or be put into use.

[0099] In addition, to further ensure the performance of the power module, functional tests can be performed, including but not limited to dynamic and static tests under normal and high temperature environments, as well as insulation withstand voltage tests. If the test results show that the electrical performance test results of the power module are all normal, and all test data are no different from those of the module without dry ice blasting cleaning, then the functional test is passed.

[0100] This invention provides an adhesive overflow cleaning device for implementing the adhesive overflow cleaning method described above, as shown in Figures 2, 3, and 4. The device includes:

[0101] A pre-cooling assembly (not shown) is used to pre-cool the target semiconductor device 100 having excess adhesive 200.

[0102] The device body 1 is equipped with an XYZ axis slide module 2, and the device body 1 is connected to a grounding wire 11.

[0103] The clamp 3 is disposed on the device body 1 and is used to load at least one pre-cooled target semiconductor device 100.

[0104] The spraying assembly 4 is set on the XYZ axis slide module 2 and is used to perform dry ice spraying on the excess adhesive 200 of the target semiconductor device 100 after pre-cooling treatment to remove the excess adhesive 200.

[0105] Grounding component 6 forms electrical contact with target semiconductor device 100 and clamp 3 to release the static charge generated by dry ice spray through clamp 3, device body 1 and grounding wire 11.

[0106] Specifically, traditional methods for removing excess epoxy resin, such as mechanical scraping, chemical etching, and laser removal, all suffer from the drawbacks of damaging the substrate surface or contaminating the module. In this embodiment, the target semiconductor device 100 with excess epoxy resin 200 is first placed in a pre-cooling assembly for pre-cooling treatment to reduce the toughness of the epoxy resin, thereby achieving efficient cleaning with lower jetting kinetic energy. In this embodiment, the pre-cooling assembly can be an existing industrial refrigerator or other equipment with refrigeration capabilities.

[0107] After the pre-cooling process is completed, one or more target semiconductor devices 100 are loaded onto the fixture 3, and then the fixture 3 is installed on the fixture fixing seat 15 of the device body 1. The device body 1 is provided with an XYZ axis slide module 2, and the spraying assembly 4 is installed on the XYZ axis slide module 2. The XYZ axis slide module 2 can drive the spraying assembly 4 to move in three-dimensional space, so that the spraying assembly 4 is aligned with the excess adhesive 200 on the target semiconductor device 100; at the same time, the spraying assembly 4 performs dry ice spraying on the excess adhesive 200, using the kinetic energy impact effect and low temperature embrittlement effect of dry ice to cause micro-cracks in the excess adhesive 200 and peel it off, thereby achieving the purpose of removing the excess adhesive 200.

[0108] During the dry ice blasting process, static charge is generated. In order to avoid damage to the target semiconductor device 100 by static electricity, the grounding component 6 forms electrical contact with the target semiconductor device 100 and the clamp 3, and releases the static charge generated by dry ice blasting to the ground in sequence through the clamp 3, the device body 1 and the grounding wire 11, so as to ensure the safety and stability of the entire cleaning process.

[0109] Furthermore, as shown in Figures 2 and 4, a spring block 13 is provided on the clamp fixing seat 15. The spring block 13 consists of a spring and a block. One end of the block is fixedly connected to one end of the first rotating shaft 12, and the other end of the first rotating shaft 12 is connected to the device body 1. The spring is sleeved on the first rotating shaft 12. When the block abuts against the side of the clamp positioning slot 31 of the clamp 3, the spring is compressed. Then the clamp is lowered and flattened. After releasing the hand, the spring returns to its original position and pushes the clamp to the left slot, thus achieving clamping and limiting.

[0110] Furthermore, it also includes: a first motor, which is fixedly mounted on the device body 1. The output shaft of the first motor is connected to the first rotating shaft 12 and is used to drive the first rotating shaft 12 to rotate, thereby enabling the control of the clamp fixing seat 15 and the clamp 3 thereon to rotate 360°.

[0111] Furthermore, the spring pressure block 13 is located on one side or on both opposite sides of the clamp 3. When the spring pressure block 13 is only provided on one side of the clamp 3, a fixed pressure block can be provided on the opposite side of the clamp 3. The fixed pressure block has a similar structure to the spring pressure block 13, and also includes a rotating shaft and a pressure block. The difference is that the rotating shaft of the fixed pressure block is fixedly connected to the device body 1, and no spring is provided on the rotating shaft.

[0112] Furthermore, the device body 1 is also equipped with at least one flow meter 14. The flow meter 14 is aligned with the fixture position to detect the flow rate of the dry ice sprayed by the spraying assembly 4 and compares the actual spray flow rate with the set target spray flow rate. When the actual spray flow rate is found to be inconsistent with the set target spray flow rate, the XYZ axis slide module 2 will drive the spraying assembly 4 to move along the preset path after the flow rate stabilizes. If the target spray flow rate is not reached after a preset time, an alarm message can be issued to facilitate the operator's inspection and maintenance of the spraying assembly 4.

[0113] Furthermore, the device body 1 is also provided with a groove, where the aforementioned first rotating shaft 12, flow meter 14, and clamp 3 are disposed. Furthermore, the groove has an inverted trapezoidal cross-section.

[0114] Furthermore, as shown in Figure 2, the spraying assembly 4 is a dry ice blasting machine. Exemplarily, the dry ice blasting machine includes a dry ice hopper 41, a grinding component 42, a motor 43, a dry ice flow control component 44, a compressed air control component 45, and a spray gun 46. The dry ice hopper 41, grinding component 42, dry ice flow control component 44, compressed air control component 45, and spray gun 46 are sequentially arranged and connected. The motor 43 is connected to the grinding component 42 and is used to drive the grinding component 42 to grind the large first dry ice particles. The dry ice is stored in the insulated dry ice hopper 41 to reduce losses caused by dry ice sublimation and ensure that it maintains a good physical state and performance before use.

[0115] Further, exemplarily, as shown in FIG2, the XYZ axis slide module 2 includes a first guide rail 21, a second slider guide rail 22, a third slider 23, a fourth slide rail 25, a fifth slider 26, and a second rotating shaft 24; wherein, the first guide rail 21 includes two parts, which are disposed on the device body 1 and located on both sides of the groove; the second slider guide rail 22 is C-shaped and spans above the fixture 3; the sliders on the two arms of the second slider guide rail 22 are slidably connected to the two first guide rails 21 respectively; the third slider 23 is slidably connected to the guide rail of the second slider guide rail 22; the fourth slide rail 25 is slidably connected to the third slider 23; and the fifth slider 26 is slidably connected to the fourth slide rail 25; one end of the second rotating shaft 24 is connected to a second motor, the second motor is fixedly connected to the fifth slider 26, and the other end of the second rotating shaft 24 is fixedly connected to the spray gun 46.

[0116] The slider of the second slider guide 22 can be driven by an existing drive assembly, so that the second slider guide 22 moves along the length direction of the first guide 21, thereby driving the XYZ axis slide module 2 as a whole to move the spray gun 46, realizing the movement of the spray gun 46 in the Y-axis direction.

[0117] The third slider section 23 can also be driven by the existing drive components, so that the third slider section 23 moves along the length direction of the second slider guide section 22, thereby driving the spray gun 46 to move as a whole in the XYZ axis slide module 2, realizing the movement of the spray gun 46 in the X-axis direction.

[0118] The fifth slider 26 can also be driven by the existing drive components, so that the fifth slider 26 moves along the length direction of the fourth slide rail 25, thereby driving the spray gun 46 to move as a whole in the XYZ axis slide module 2, realizing the movement of the spray gun 46 in the Z axis direction.

[0119] The second motor drives the second rotating shaft 24 to rotate. During the rotation of the second rotating shaft 24, the spray gun 46 connected to it will also rotate, so that the spray gun 46 can rotate from 45° to 135° in the XZ plane.

[0120] It should be noted that the aforementioned drive components are well-known and mature technologies in the mechanical field. The structure and working principle of the drive components will not be described in detail here, but they should be included within the scope of protection of this invention.

[0121] Furthermore, as shown in Figures 4 and 5, the fixture 3 includes:

[0122] The clamp body 30 is provided with at least one clamp positioning slot 31, at least one module positioning slot 32 and a corresponding module spring slot 33. The clamp positioning slot 31 is located on the edge of the clamp body 30 and cooperates with the spring block 13 on the device body 1 to fix the clamp 3 on the device body 1.

[0123] The module positioning slot 32 is used to load the target semiconductor device 100, and the module spring slot 33 abuts against the target semiconductor device 100 loaded in the module positioning slot 32 to fix the target semiconductor device 100.

[0124] At least one metal pressure bar 34, with both ends of each metal pressure bar 34 mounted on the clamp body 30 via pressure bar fixing blocks 35, and at least one grounding component 6 sleeved on each metal pressure bar 34; the number of grounding components 6 corresponds one-to-one with the number of target semiconductor devices 100;

[0125] Each metal pressure bar 34 is fitted with a V-shaped spring 37. Under the elastic force of the V-shaped spring 37, the grounding component 6 on the metal pressure bar 34 forms an electrical contact with the target semiconductor device 100, and flips under the action of external force and is fixed by the pressure bar flipping fixing hook 36, which is set on the clamp body 30.

[0126] Specifically, the fixture 3 is equipped with multiple module positioning slots 32, each corresponding to a workstation. Figure 4 shows an example with 8 workstations, allowing 8 power modules to be processed at once. In fact, fewer or more workstations can be set, which is not limited here.

[0127] A module spring slot 33 is provided on the edge of the module positioning slot 32 for fixation. Its principle is the same as that of a clamp fixing to a device, and the structure of the module spring slot 33 will not be described in detail here. Specifically, as shown in Figure 6, the side of the power module abuts against the module spring slot 33, compressing the spring. Then, the module is lowered and laid flat. After releasing the handle, the spring returns to its original position, pushing the module towards the left slot, achieving clamping and limiting. This ensures precise positioning of the power module and prevents displacement during operation.

[0128] In this embodiment, the fixture positioning groove 31 is a recess formed on the opposite two sides of the fixture body 30. The shape of the fixture positioning groove 31 is adapted to the shape of the spring pressure block 13 on the device body 1. By cooperating with the spring pressure block 13 on the opposite sides and the fixture positioning groove 31, the fixture 3 is fixed to the device body 1, making it easy to remove the fixture 3 for manual loading.

[0129] At least one metal pressure bar 34 is installed above the clamp body 30, and the metal pressure bar 34 is connected to the clamp body 30 through a pressure bar fixing block 35.

[0130] The metal pressure bar 34 is locked and unlocked via a pressure bar flip-locking hook 36. The pressure bar flip-locking hook 36 preferably employs an existing locking spring check mechanism. Specifically, a return spring is installed inside the pressure bar flip-locking hook 36. When cleaning is complete or when the power module needs to be removed from the clamp 3, the metal pressure bar 34 is flipped, and the return spring's elastic force combined with the limiting action of the pressure bar flip-locking hook 36 locks the metal pressure bar 34.

[0131] Before cleaning, gently push the pressure rod to the left to flip the fixing hook 36. The return spring is pressed, releasing the limit and releasing the metal pressure rod 34. A grounding component 6 is attached to the contact point between the metal pressure rod 34 and the module's heat dissipation surface. Under the elastic force of the V-shaped spring 37, the grounding component 6 at the contact point between the metal pressure rod 34 and the module's heat dissipation surface is pressed tightly against the module's metal heat dissipation surface with a certain pressure. Since the metal pressure rod 34 is connected to the fixture body 30 through the pressure rod fixing block 35, and the fixture body 30 is connected to the ground through the machine body grounding wire 11 of the device body 1, the static charge generated during the cleaning process is conducted away in real time from the heat dissipation surface → grounding component 6 → metal pressure rod 34 → fixture 3 → device body 1 → ground, ensuring that the entire processing process is in a static safety state.

[0132] Furthermore, the fixture 3 is preferably made of aluminum alloy.

[0133] Furthermore, the grounding component 6 includes an elastic conductor, which is any one or a combination of two of conductive sponge and conductive rubber.

[0134] Furthermore, it also includes:

[0135] The negative pressure adsorption component 5 is located inside the device body 1 and below the clamp 3.

[0136] Specifically, the negative pressure adsorption component 5 includes a fan 51 and a dust collection box 52. Specifically, the groove below the clamp 3 is a cavity-type space with an inverted trapezoidal cross-section. The negative pressure adsorption component 5, by setting the fan 51, forms a negative pressure, so that the peeled adhesive debris and carbon dioxide gas are sucked into the dust collection box 52 in real time and efficiently, preventing the debris from causing secondary pollution to the cleaning area and maintaining a clear working view.

[0137] The following provides a specific embodiment to illustrate the above technical solution:

[0138] A certain type of SiC power module was selected as the target semiconductor device 100. Its metal heat dissipation surface is made of copper with nickel plating, and the excess adhesive 200 is epoxy resin cured at high temperature with a thickness of about 0.1mm-0.3mm.

[0139] Before dry ice blasting, the power modules are first pre-cooled. Specifically, the modules are placed in batches in an industrial freezer with a set temperature of -10℃ to 10℃ and left to stand for 5 to 60 minutes.

[0140] Next, the SiC power modules to be cleaned are placed on fixture 3. Fixture 3 has precision module positioning slots 32, which are fixed by module spring slots 33, ensuring accurate positioning of the power modules and preventing displacement during operation. Fixture 3 has 8 workstations, allowing for the processing of 8 modules at once. Fixture 3 is fixed to the device body 1 via fixture positioning slots 31 and spring blocks 13, facilitating the removal of fixture 3 for manual loading.

[0141] Next, set the dry ice injection parameters. On the main interface of the touch screen controller, set the core parameters as follows: injection pressure is 0.10~2MPa, and injection flow rate is 0.1~1L / min.

[0142] By connecting to a robot teach pendant, the motion parameters of the XYZ axis slide module 2 and the spraying component 4 can be manually programmed, including but not limited to the automatic running speed of the XYZ axis slide module 2, dry ice flow detection, ice blowing on / off, the movement path of the spray gun 46, the movement speed of the spray gun 46, and the path array matrix. Multiple programs can be saved, and different programs can be selected and switched on the main interface of the touch screen controller.

[0143] The main motion parameters of the program in this embodiment are as follows:

[0144] Dry ice flow detection: Set up dry ice flow detection at the beginning of the program.

[0145] Spray gun movement path: Based on the position of the overflow glue 200 on the metal heat dissipation surface of the power module, set the running line segment, and then set a 2×4 array matrix for the line segment so that 8 power modules can be processed at one time.

[0146] Spraying speed: 2–20 mm / s. Adjust the spraying speed according to the severity of adhesive overflow (200).

[0147] Spraying distance: 10-100mm. Adjust the spraying distance according to the severity of adhesive overflow.

[0148] Spray angle: 45°~90° (relative to the heat dissipation surface).

[0149] Next, the overflow cleaning system is activated. After the entire system is started, dry ice particles with a diameter of 1-5 mm and a length of <5 cm are crushed into finer particles by the dry ice particle grinding component 42 in the dry ice hopper 41. The crushing process is achieved by the motor 43 driving the rollers to rotate; the dry ice falls and is crushed by the rollers, resulting in dry ice particles with a diameter of approximately 0.1-1.5 mm. The crushed dry ice is then transported through pipelines, mixed with compressed air provided by the compressed air control component 45, and finally ejected from the nozzle of the spray gun 46. After the dry ice is ejected, the XYZ axis slide module 2 moves the spray gun 46 to the flow meter 14 for flow detection. When the detected spray flow rate does not meet the set target, a waiting instruction has been written into the program. The spray gun 46 will continue to spray ice and then wait for the flow rate to stabilize. When the detected spray flow rate meets the set target, the XYZ axis slide module 2 drives the spray gun 46 to start moving along the predetermined path written into the program, spraying dry ice on each workpiece and cleaning up the epoxy resin overflow 200.

[0150] To overcome the static electricity hazards generated by dry ice spraying, an anti-static device, namely a grounding component 6, is added to the clamp 3 of this invention. Specifically, a metal pressure rod 34 is installed above the clamp body 30, and a conductive sponge is adhered to the contact point between the metal pressure rod 34 and the heat dissipation surface of the module. When the power module is fixed, the metal pressure rod 34, through the elastic force of the V-shaped spring 37, presses the conductive sponge at the contact point with the heat dissipation surface of the module tightly against the metal heat dissipation surface of the module with a certain pressure. When removing the component, the metal pressure rod 34 is flipped to the other side, and can be fixed by the pressure rod flipping fixing hook 36. The pressure rod flipping fixing hook 36 is equipped with a return spring. After the metal pressure rod 34 is flipped and pressed down, the elastic force of the spring and the limiting position of the pressure rod flipping fixing hook 36 lock the metal pressure rod 34. Pushing the pressure rod flipping fixing hook 36 slightly to the left compresses the spring, thereby releasing the limiting position and releasing the metal pressure rod 34. The metal pressure bar 34 is connected to the clamp body 30 via the pressure bar fixing block 35, and the clamp body 30 is connected to the ground via the grounding wire 11 of the device body 1. In this way, the static charge generated during the cleaning process can be conducted away in real time through the path of heat dissipation surface → conductive sponge → metal pressure bar 34 → clamp 3 → equipment body → ground, ensuring that the entire processing process is in a static-safe state.

[0151] During the processing, two physical effects work together:

[0152] Kinetic impact effect: Driven by compressed air at 0.1–2.0 MPa, extremely fast dry ice particles impact the epoxy resin surface with extremely high kinetic energy. Each dry ice particle is like a miniature impact hammer, applying enormous impact stress to the resin layer in an instant.

[0153] Low-temperature embrittlement effect: When dry ice (-78.5℃) comes into contact with the pre-cooled overflow adhesive 200, an extremely strong heat exchange occurs instantly, causing the local temperature of overflow adhesive 200 to drop sharply, and its glass transition temperature (Tg) is exceeded, causing the material to change from a tough state to a brittle state.

[0154] Under the combined effect of these two factors, a micro-crack network is generated inside the Exudate 200. Continuous impacts cause the cracks to expand and converge, eventually leading to the gradual peeling and pulverization of the Exudate 200 surface layer by layer. Meanwhile, the dry ice particles sublimate instantly after impact (changing directly from solid carbon dioxide to gas), expanding in volume by nearly 800 times. The micro-explosion effect generated by this phase transition process also helps to remove the broken particles from the substrate surface.

[0155] The negative pressure adsorption component 5 is always on to ensure a clean working environment. As shown in Figure 2, the negative pressure adsorption component 5 creates negative pressure by installing a fan 51 below the clamp 3, which allows the peeled epoxy glue debris and carbon dioxide gas to be sucked into the dust collection box 52 in real time and efficiently, preventing secondary pollution of the cleaned area by the debris and maintaining a clear working view.

[0156] The entire cleaning process takes approximately 300 seconds, depending on the length of the program path and the speed of movement set based on the 200mm area of ​​spilled adhesive.

[0157] After cleaning, the XYZ axis slide module 2 automatically returns to its original position, and the device stops operating. The operator removes the power module from the fixture 3. Finally, the removed power module is placed under lighting conditions for visual inspection and flatness measurement; functional tests can also be performed, including but not limited to dynamic and static tests under normal and high temperature environments, as well as insulation withstand voltage tests.

[0158] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made using the content of this specification and illustrations should be included within the protection scope of the present invention.

Claims

1. A method for cleaning up excess adhesive, characterized in that, The method, applied to a target semiconductor device with excess adhesive, includes: step S1, pre-cooling the target semiconductor device; step S2, dry-ice blasting the excess adhesive from the pre-cooled target semiconductor device to remove the excess adhesive; and step S3, making electrical contact with the target semiconductor device through a grounding component to release the static charge generated by the dry-ice blasting.

2. The method for cleaning excess adhesive according to claim 1, characterized in that, Step S1 includes: placing the target semiconductor device in a preset temperature environment to pre-cool the excess adhesive; wherein the preset temperature environment is -10℃ to 10℃.

3. The method for cleaning excess adhesive according to claim 1, characterized in that, In step S2, the dry ice sprayed in the dry ice spraying process is a second type of dry ice particles.

4. The method for cleaning excess adhesive according to claim 3, characterized in that, The second dry ice particle has a particle size of 0.1 mm to 2.0 mm; and / or the second dry ice particle is formed by grinding the first dry ice particle, the first dry ice particle is cylindrical, the nominal diameter of the first dry ice particle is 3 mm to 5 mm, and the length of the first dry ice particle is less than 5 cm.

5. The method for cleaning excess adhesive according to claim 1, characterized in that, The dry ice blasting process satisfies any one or more of the following blasting conditions: the dry ice is blasted at a preset pressure, which is 0.1 MPa to 2.0 MPa; the dry ice blasting flow rate is 0.1 L / min to 1 L / min; the dry ice blasting distance is 10 mm to 200 mm; the dry ice blasting angle relative to the plane of the target semiconductor device is 45° to 90°; the dry ice blasting process is carried out under preset environmental conditions, which include: an ambient temperature of 18°C ​​to 28°C and an ambient humidity of 30% RH to 60% RH; the dry ice blasting process uses a blasting gun, which moves along a preset path and blasts dry ice at a preset speed, which is 2 mm / s to 150 mm / s.

6. The method for cleaning excess adhesive according to claim 1, characterized in that, Step S2 further includes: simultaneously with or after the dry ice blasting process, applying negative pressure to adsorb the excess adhesive that has been removed from the target semiconductor device.

7. An adhesive overflow cleaning device, characterized in that, An apparatus for implementing the adhesive overflow removal method as described in any one of claims 1-6, comprising: a pre-cooling assembly for pre-cooling a target semiconductor device with adhesive overflow; an apparatus body having an XYZ axis slide module and a grounding wire connected thereto; a clamp disposed on the apparatus body for loading at least one pre-cooled target semiconductor device; a spraying assembly disposed on the XYZ axis slide module for dry ice spraying of the adhesive overflow from the pre-cooled target semiconductor device to remove the adhesive overflow; and a grounding assembly forming electrical contact with the target semiconductor device and the clamp to release the static charge generated by dry ice spraying through the clamp, the apparatus body, and the grounding wire.

8. The adhesive overflow cleaning device according to claim 7, characterized in that, The clamp includes: a clamp body, which has at least one clamp positioning slot, at least one module positioning slot, and a corresponding module spring slot. The clamp positioning slot is located on the edge of the clamp body and cooperates with a spring block on the device body to fix the clamp onto the device body. The module positioning slot is used to load the target semiconductor device, and the module spring slot abuts against the target semiconductor device loaded in the module positioning slot to fix the target semiconductor device. At least one metal pressure rod is mounted on the clamp body at both ends by pressure rod fixing blocks. At least one grounding component is sleeved on each metal pressure rod. A V-shaped spring is sleeved on each metal pressure rod. Under the elastic force of the V-shaped spring, the grounding component on the metal pressure rod forms electrical contact with the target semiconductor device, and the metal pressure rod flips under external force and is fixed by a pressure rod flipping fixing hook, which is located on the clamp body.

9. The adhesive overflow cleaning device according to claim 7, characterized in that, The grounding component includes an elastic conductor, which is any one or a combination of two of conductive sponge and conductive rubber.

10. The adhesive overflow cleaning device according to claim 7, characterized in that, It also includes a negative pressure adsorption component, which is disposed inside the main body of the device and located below the clamp.

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