Cleaning mode of power module

Abstract

The invention relates to a cleaning method of a power module, the power module comprises a power module body, the power module body is composed of a copper layer substrate, DIE wafers and a ceramic substrate which are sequentially arranged from top to bottom, the number of the DIE wafers is multiple, the DIE wafers are uniformly distributed on the upper surface of the ceramic substrate, and the adjacent DIE wafers are electrically connected through bonding wires. Compared with a traditional mode of direct plastic packaging after double-solution cleaning, the mode of double-solution cleaning and plasma cleaning can effectively improve the surface energy of the module, so that the module is easier to combine with a plastic packaging material in the plastic packaging stage; compared with a traditional single-solution cleaning and plasma cleaning mode, due to the fact that rinsing liquid in the double solutions has a certain reduction effect, compared with a single-solution cleaning system for cleaning the module only through cleaning liquid, the module cleaned through the double solutions is not prone to serious oxidation after being subjected to plasma cleaning, and the service life of the module is prolonged. Therefore, the risk of layering of the module in the plastic packaging stage due to oxidation factors is reduced; the mode is suitable for most plastic package power modules.

Description

Technical Field

[0001] The invention belongs to the technical field of photovoltaic electronic devices and relates to a cleaning method for a power module. Background Art

[0002] In recent years, as the government pays more attention to environmental protection, the waste liquid discharge standards of electronic packaging plants have become increasingly stringent, which has become an inevitable trend. Therefore, the currently more common single-solution cleaning liquid has gradually been replaced by dual-solution cleaning liquid due to environmental protection issues.

[0003] However, in actual use, it is found that compared with single solution cleaning, the double solution cleaning module has a problem of lower surface energy after cleaning, which will undoubtedly bring the risk of delamination on the module after plastic sealing in the subsequent plastic sealing process, which will lead to reduced reliability and even module failure. Therefore, a new power module cleaning method is designed to overcome the above problems. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a cleaning method for a power module which has a simple and reasonable structure, is practical and convenient, is environmentally friendly and efficient, and has high reliability.

[0005] The present invention is implemented through the following technical scheme: a power module, including a power module body, the power module body is composed of a copper layer substrate, a DIE chip and a ceramic substrate arranged in sequence from top to bottom, the DIE chips are multiple and evenly distributed on the upper surface of the ceramic substrate, and adjacent DIE chips are electrically connected through bonding wires.

[0006] Preferably, the outer sides of the copper substrate, DIE chip and ceramic substrate are first cleaned and then sealed with EMC plastic sealing material, so that the copper substrate, DIE chip and ceramic substrate form a whole, and the lower surface of the ceramic substrate is used as a welding surface.

[0007] A power module cleaning method, wherein the power module body is firstly cleaned with double solutions before injection molding to remove pollutants on the module caused by the previous process, and then plasma cleaned to further remove pollutants on the module while increasing the hydrophilicity of the copper layer substrate and reducing the water drop angle so that it can be better combined with the EMC plastic packaging material, and finally plastic packaging is performed.

[0008] Preferably, the cleaning area adopted by the dual-solution cleaning system consists of a condensation layer, a steam layer, a cleaning liquid area and a rinsing liquid area, one side of the steam layer is adjacent to the condensation layer, and the cleaning liquid area and the rinsing liquid area are respectively arranged at both ends of the other side of the steam layer, the cleaning liquid area and the rinsing liquid area are separated by an isolation area, the cleaning liquid area is used to place the cleaning liquid, and the rinsing liquid area is used to place the rinsing liquid; during the cleaning process, the power module first enters the steam layer for preheating, and then enters the cleaning liquid for cleaning, and after cleaning, it is placed in the rinsing liquid to rinse off the residual cleaning liquid on the module, and after rinsing, it rises to the steam layer for steam cleaning, and then removes the rinsing liquid on the module in the condensation layer.

[0009] Preferably, in the dual solution cleaning system, the temperature of the cleaning solution should be set between 65-75°C, the temperature of the rinsing solution should be set between 45-55°C; and the temperature of the steam layer should be set between 55-65°C.

[0010] Preferably, the immersion time in the cleaning solution of the double solution needs to be set between 350-500s; the immersion time in the rinsing solution needs to be set between 350-500s; the cleaning time in the steam layer needs to be set between 60-120s, and the condensation time in the condensation layer needs to be set between 60-120s.

[0011] Preferably, the cleaning area used in the plasma cleaning is composed of a power supply, a closed reaction chamber, an upper electrode plate, a lower electrode plate, and a process gas, wherein the upper electrode plate and the lower electrode plate are respectively arranged at the bottom of the closed reaction chamber, the power supply is arranged outside the closed reaction chamber, and the process gas is arranged between the upper and lower electrode plates inside the closed reaction chamber. During the cleaning process, the power module generates an electric field between the upper and lower electrode plates through the power supply, and then the molecules of the process gas inside the closed reaction chamber are ionized to form plasma, and the active particles in the plasma (such as positively charged ions, negatively charged electrons, etc.) collide with the surface of the power module under the action of the electric field, thereby achieving the cleaning goal.

[0012] Preferably, the plasma cleaning time is between 5 and 15 seconds.

[0013] Preferably, the cleaning power of the plasma cleaning is between 50-150W.

[0014] Preferably, the power module body is a power module used in the photovoltaic field.

[0015] The beneficial effects of the present invention are as follows:

[0016] Compared with the traditional method of direct plastic sealing after double solution cleaning, the double solution cleaning + plasma cleaning method adopted in the present invention can effectively improve the surface energy of the power module, making the power module easier to combine with the plastic sealing material during the plastic sealing stage; compared with the traditional single solution cleaning + plasma cleaning method, since the cleaning liquid in the double solution has a certain reducing effect, the module after double solution cleaning is less likely to be severely oxidized after plasma cleaning than the module cleaned with a single solution, thereby reducing the risk of stratification of the module during the plastic sealing stage; this method is suitable for most plastic-sealed power modules. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of the plastic package of the power module in the present invention;

[0018] Figure 2 It is a flow chart of the cleaning method of the present invention;

[0019] Figure 3 This is an example diagram of the double solution cleaning process of the present invention;

[0020] Figure 4 This is an example diagram of the plasma cleaning process of the present invention. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to more clearly understand the objectives, technical solutions and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0022] In the description of the present invention, it is necessary to understand that the orientation or position relationship indicated by the terms such as "up", "down", "left", "right", "inside", "outside", "horizontal" and "vertical" is based on the orientation or position relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] In the description of the present invention, the confirmation of the surface activity of the power module is achieved by measuring the water drop angle.

[0024] The present invention will be described in detail below with reference to the accompanying drawings: Figure 1As shown, a power module includes a power module body, which is composed of a copper layer substrate 1, a DIE chip 2 and a ceramic substrate 5 arranged in sequence from top to bottom. The DIE chips 2 are multiple and evenly distributed on the upper surface of the ceramic substrate 5. Adjacent DIE chips 2 are electrically connected through bonding wires. The outer sides of the copper layer substrate 1, the DIE chip 2 and the ceramic substrate 5 are first cleaned and then plastic-sealed with an EMC plastic sealing material 4, so that the copper layer substrate 1, the DIE chip 2 and the ceramic substrate 5 form a whole, and the lower surface of the ceramic substrate 5 is used as a welding surface 6.

[0025] like Figure 2 As shown, a cleaning method of a power module is shown, in which the power module body is first cleaned with a double cleaning liquid and then plasma cleaned before injection molding, which is used to increase the hydrophilicity of the copper layer substrate and reduce the water drop angle so that it can be better combined with the EMC molding material 5, and finally the molding is performed.

[0026] In the dual solution system, the density of the rinsing liquid and the cleaning liquid cannot be the same, the density of the cleaning liquid should be lower than that of the rinsing liquid, and the cleaning liquid and the rinsing liquid are not miscible.

[0027] In the dual solution system, the boiling point of the cleaning solution should not be higher than 100° C. to avoid affecting the components on the power module.

[0028] like Figure 3 As shown, the cleaning area adopted by the dual-solution cleaning system is composed of a condensation layer 11, a steam layer 7, a cleaning liquid area 8 and a rinsing liquid area 9. One side of the steam layer 7 is adjacent to the condensation layer 11, and the cleaning liquid area 8 and the rinsing liquid area 9 are respectively arranged at both ends of the other side of the steam layer. The cleaning liquid area 8 and the rinsing liquid area 9 are separated by an isolation area 10. The cleaning liquid area 8 is used for placing cleaning liquid, and the rinsing liquid area 9 is used for placing rinsing liquid, and the liquid level of the rinsing liquid is level with the isolation area 10.

[0029] like Figure 3 As shown, the dual solution cleaning system provides heating to the cleaning liquid area 8 and the rinsing liquid area 9 through a heating system. The cleaning liquid in the cleaning liquid area 8 needs to be heated to the boiling point, and the rinsing liquid in the rinsing liquid area 9 needs to be heated to the process temperature set by the machine. The cleaning liquid in the cleaning liquid area 8 vaporizes after boiling and enters the steam layer 7. Finally, the cleaning liquid vapor rises into the condensation layer 11, liquefies in the condensation layer 11, and flows back to the cleaning liquid area 8 and the rinsing liquid area 9. Since the cleaning liquid and the rinsing liquid are not miscible, and the density of the cleaning liquid is less than that of the rinsing liquid, the cleaning liquid that flows back to the rinsing liquid area 9 will float on the surface of the rinsing liquid, and because the rinsing liquid level is level with the isolation area 10, the cleaning liquid floating on the surface of the rinsing liquid will flow back to the cleaning liquid area 8 to complete the cycle.

[0030] like Figure 3As shown, during the cleaning process, the power module first enters the steam layer 7 for preheating, and then enters the cleaning liquid for cleaning. After cleaning, it is placed in the rinsing liquid to rinse off the residual cleaning liquid on the module. After rinsing, it rises to the steam layer 7 for steam cleaning, and then the rinsing liquid on the module is removed in the condensation layer 11.

[0031] like Figure 4 As shown, the cleaning area used in the plasma cleaning is composed of a power supply 12, a closed reaction chamber 13, an upper electrode plate 14, a lower electrode plate 15, and a process gas 16, wherein the upper electrode plate 14 and the lower electrode plate 15 are respectively arranged at the bottom of the closed reaction chamber 13, the power supply 12 is arranged outside the closed reaction chamber 13, and the process gas 16 is arranged between the upper and lower electrode plates inside the closed reaction chamber 13. During the cleaning process of the power module, an electric field is generated between the upper and lower electrode plates by the power supply 12, and then the molecules of the process gas 16 inside the closed reaction chamber 13 are ionized to form plasma, and the active particles in the plasma (such as positively charged ions, negatively charged electrons, etc.) collide with the surface of the power module under the action of the electric field, thereby achieving the cleaning goal.

[0032] In the dual-solution cleaning system, the temperature of the cleaning liquid in the cleaning liquid area 8 needs to be set between 65-75°C, the temperature of the rinsing liquid in the rinsing liquid area 9 needs to be set between 45-55°C; the temperature of the cleaning liquid steam in the steam layer 11 needs to be set between 55-65°C. In the dual-solution cleaning system, the time for the power module to be immersed in the cleaning liquid area 8 during cleaning should be set between 350-500s; the time for immersion in the rinsing liquid area 9 should be set between 350-500s; the time for cleaning in the steam layer 7 should be set between 60-120s, and the time for condensation in the condensation layer 11 should be set between 60-120s.

[0033] The time parameter of the plasma cleaning needs to be set between 5-15s. The cleaning power parameter of the plasma cleaning needs to be set between 50-150W.

[0034] The power module body is a power module used in the photovoltaic field.

[0035] Example

[0036] In some embodiments, the cleaning solution temperature of the double solution cleaning needs to be set at 65-75°C, the rinsing solution temperature needs to be set at 45-55°C; and the steam layer temperature needs to be set at 55-65°C.

[0037] In some embodiments, the cleaning time of the double solution cleaning should be set between 350-500 seconds; the rinsing time should be set between 350-500 seconds; and the steam cleaning time should be set between 60-120 seconds.

[0038] In some embodiments, 12 pcs of power modules after double solution cleaning and 12 pcs of power modules after single solution cleaning are respectively extracted for water drop angle detection, and the detection data are shown in the following table. From the detection results, it can be seen that the water drop angle value of the module after double solution cleaning is significantly higher than the water drop angle value of the module after single solution cleaning.

[0039]

[0040]

[0041] In some embodiments, the plasma cleaning time is between 5-15 seconds, and the cleaning power of the plasma cleaning is between 50-150W.

[0042] In some embodiments, 12 pcs of power modules after double solution cleaning and 12 pcs of power modules after single solution cleaning are respectively selected, and water drop angle detection is performed after plasma cleaning. The detection data are shown in the following table. From the detection results, it can be seen that there is no significant difference between the water drop angle values ​​of the modules after double solution cleaning + plasma cleaning and the water drop angle values ​​of the modules after single solution cleaning + plasma cleaning.

[0043]

[0044]

[0045] In some embodiments, 12 pcs of power modules after double solution cleaning and 12 pcs of power modules after single solution cleaning were respectively extracted, and the oxidation status of the modules was observed 30 minutes after plasma cleaning. The detection data are shown in the following table. From the detection results, it can be seen that the severity of oxidation of the modules after double solution cleaning + plasma cleaning is significantly lighter than that of the modules after single solution cleaning + plasma cleaning.

[0046]

[0047]

[0048] In some embodiments, molding is performed within 30 minutes after plasma cleaning to achieve better bonding strength.

[0049] The specific embodiments described herein are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A power module, comprising a power module body, characterized in that: The power module body is composed of a copper layer substrate (1), a DIE chip (2) and a ceramic substrate (5) which are arranged in sequence from top to bottom; the DIE chips (2) are multiple and evenly distributed on the upper surface of the ceramic substrate (5); adjacent DIE chips (2) are electrically connected via bonding wires.

2. The power module according to claim 1, characterized in that: The outer sides of the copper layer substrate (1), the DIE chip (2) and the ceramic substrate (5) are first cleaned and then plastic-sealed using an EMC plastic-sealing material (4), so that the copper layer substrate (1), the DIE chip (2) and the ceramic substrate (5) form a whole, and the lower surface of the ceramic substrate (5) serves as a welding surface (6).

3. A method for cleaning a power module according to claim 1 or 2, characterized in that: The power module body is first cleaned with a double solution and then with plasma before injection molding, which removes pollutants on the surface of the power module, increases the hydrophilicity of the copper layer substrate, reduces the water drop angle, and allows it to better bond with the EMC molding compound (5), and finally is molded.

4. The cleaning method according to claim 3, characterized in that: The cleaning area used in the dual-solution cleaning system is composed of a condensation layer (11), a steam layer (7), a cleaning liquid area (8) and a rinsing liquid area (9); one side of the steam layer (7) is adjacent to the condensation layer (11); the other side of the steam layer is provided with a cleaning liquid area (8) and a rinsing liquid area (9) at both ends; the cleaning liquid area (8) and the rinsing liquid area (9) are separated by an isolation area (10); the cleaning liquid area (8) is used to place the cleaning liquid; the rinsing liquid area (9) is used to place the rinsing liquid; and the level of the rinsing liquid is level with the isolation area. During the cleaning process, the power module first enters the steam layer (7) for preheating, and then enters the cleaning liquid area (8) for cleaning. After cleaning, it is placed in the rinsing liquid area (9) to rinse off the cleaning liquid remaining on the module. After rinsing, it rises into the steam layer (7), and the clean steam generated by the boiling of the cleaning liquid in the cleaning liquid area (8) is used to finely clean the power module, and then condenses in the condensation layer (11) to further remove pollutants on the module.

5. The cleaning method according to claim 3, characterized in that: The cleaning area used in the plasma cleaning is composed of a power supply (12), a closed reaction chamber (13), an upper electrode plate (14), a lower electrode plate (15), and a process gas (16), wherein the upper electrode plate (14) and the lower electrode plate (15) are respectively arranged at the bottom of the closed reaction chamber (13), the power supply (12) is arranged outside the closed reaction chamber (13), and the process gas (16) is arranged between the upper and lower electrode plates inside the closed reaction chamber (13). During the cleaning process of the power module, an electric field is generated between the upper and lower electrode plates by the power supply (12), and then the molecules of the process gas (16) inside the closed reaction chamber (13) are ionized to form plasma, and the active particles in the plasma collide with the surface of the power module under the action of the electric field, thereby achieving the cleaning purpose.

6. The cleaning method according to claim 5, characterized in that: In the double solution, the temperature of the cleaning solution is between 65-75°C, the temperature of the rinsing solution is between 45-55°C; and the temperature of the steam layer is between 55-65°C.

7. The cleaning method according to claim 6, characterized in that: In the double solution, the cleaning time is between 350-500 seconds; the rinsing time is between 350-500 seconds; and the steam washing time is between 60-120 seconds.

8. The cleaning method according to claim 5 or 7, characterized in that: The plasma cleaning time is between 5 and 15 seconds.

9. The cleaning method according to claim 8, characterized in that: The plasma cleaning power is between 50-150W.

10. The cleaning method according to claim 1 or 4, characterized in that: The power module body is a power module used in the photovoltaic field.

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