Method of forming a protective film on an electronic module

Abstract

The present application provides a method for forming a protective film on an electronic module, comprising: placing the electronic module and a protective material placed on the electronic module into a cavity; performing a first heating procedure on the protective material in the cavity and performing a first pressure increasing procedure on the cavity, wherein the pressure of the first pressure increasing procedure is greater than 1 atmosphere; after the protective material is softened, maintaining the first heating procedure and performing a pressure decreasing oscillation procedure on the cavity, wherein the pressure decreasing oscillation procedure comprises alternately changing the pressure of the cavity between multiple low pressures which are lower than 1 atmosphere; maintaining the first heating procedure and performing a second pressure increasing procedure on the cavity, wherein the pressure of the second pressure increasing procedure is less than the pressure of the first pressure increasing procedure and greater than 1 atmosphere; and performing a second heating procedure on the protective material in the cavity to form the protective film covering the electronic module. The method for forming a protective film on an electronic module can effectively reduce the probability of residual bubbles between the protective glue and the electronic components.

Description

Technical Field

[0001] This invention relates to a method for forming a protective film, and more particularly to a method for forming a protective film on an electronic module. Background Technology

[0002] Motherboards in electronic devices typically contain electronic components of varying sizes. Traditionally, protective adhesive is applied to the motherboard mechanically or manually to protect the motherboard and its electronic components. However, this method often results in air bubbles remaining between the adhesive and the motherboard, or between the adhesive and the electronic components, due to the adhesive not adhering tightly. This can lead to moisture buildup, reducing the lifespan of the electronic components or causing reliability issues. Summary of the Invention

[0003] This invention provides a method for forming a protective film on an electronic module, which can effectively reduce the probability of residual air bubbles remaining between the protective adhesive and the electronic components.

[0004] A method for forming a protective film on an electronic module according to the present invention includes: placing an electronic module and a protective material placed on the electronic module in a cavity, wherein the protective material and the electronic module are in contact with each other; subjecting the protective material in the cavity to a first heating process to soften the protective material placed on the electronic module, and subjecting the cavity to a first pressurization process, wherein the pressure of the first pressurization process is greater than 1 atmosphere; after softening the protective material, maintaining the first heating process, and subjecting the cavity to a depressurization oscillation process, wherein the depressurization oscillation process includes alternately varying the pressure of the cavity between a plurality of low pressures below 1 atmosphere; maintaining the first heating process, and subjecting the cavity to a second pressurization process, wherein the pressure of the second pressurization process is less than the pressure of the first pressurization process and greater than 1 atmosphere; and subjecting the protective material in the cavity to a second heating process to cure the protective material covering the electronic module to form a protective film covering the electronic module.

[0005] In one embodiment of the present invention, in the aforementioned pressure reduction oscillation procedure, these low pressures include a base low pressure and multiple variable low pressures. The pressure of the base low pressure is greater than that of these variable low pressures. These variable low pressures gradually decrease over time. These variable low pressures alternate with the base low pressure, so that between two adjacent time sequences in these variable low pressures, the pressure will first return to the base low pressure.

[0006] In one embodiment of the invention, the cavity is maintained at each of these varying low pressures for a longer period than the cavity is maintained at the base low pressure.

[0007] In one embodiment of the present invention, after the first boosting procedure and the depressurization oscillation procedure are performed, and before the second boosting procedure is performed, the method further includes: repeatedly performing the first boosting procedure and the depressurization oscillation procedure on the cavity.

[0008] In one embodiment of the present invention, the pressure difference of these low pressures in the second depressurization oscillation procedure is greater than the pressure difference of these low pressures in the first depressurization oscillation procedure.

[0009] In one embodiment of the present invention, after repeatedly performing the first pressurization procedure and the depressurization oscillation procedure on the cavity, and before performing the second pressurization procedure, the method further includes performing the first pressurization procedure and the depressurization procedure on the cavity, wherein the pressure of the depressurization procedure is less than the pressure of the depressurization oscillation procedure.

[0010] In one embodiment of the present invention, the time during which the cavity is held at the pressure of the depressurization process is longer than the time during which the cavity is held at the pressure of the depressurization oscillation process.

[0011] In one embodiment of the present invention, the pressure of the first pressurization process described above is the same as or different from the pressure of the second pressurization process.

[0012] In one embodiment of the present invention, the cavity is simultaneously subjected to a third pressurization process during the second heating process.

[0013] In one embodiment of the present invention, the electronic module includes a plurality of electronic components, and the surface contour of the protective film covering the electronic module conforms to the contour of these electronic components.

[0014] In one embodiment of the present invention, the above-mentioned electronic module includes a plurality of electronic components, and the surface of the protective film covering the electronic module is planar and not conformal to the contours of these electronic components.

[0015] Based on the above, the present invention provides a method for forming a protective film on an electronic module. First, a first heating process is performed on the protective material within a cavity to soften the protective material placed on the electronic module. Then, a first pressurization process is performed on the cavity to cause air bubbles between the electronic module and the protective material to move upwards to near the surface of the protective material. Next, the first heating process is maintained, and a depressurization oscillation process is performed on the cavity, which involves alternately varying the pressure of the cavity between multiple low pressures below 1 atmosphere. During this depressurization oscillation process, air bubbles within the protective material near the surface rupture due to the pressure changes within the cavity. Next, the first heating process is maintained, and a second pressurization process is performed on the cavity, where the pressure of the second pressurization process is less than the pressure of the first pressurization process but greater than 1 atmosphere. During the second pressurization process, the softened protective material can be flattened under pressure. Finally, a second heating process is performed on the protective material within the cavity to solidify the protective material covering the electronic module, thereby forming a protective film covering the electronic module. Attached Figure Description

[0016] Figure 1 This is a schematic diagram illustrating the steps of a method for forming a protective film on an electronic module according to an embodiment of the present invention;

[0017] Figures 2A to 2C yes Figure 1 A schematic diagram of one of the processes for forming a protective film on an electronic module;

[0018] Figures 3A to 3C yes Figure 1 Another schematic diagram of the process for forming a protective film on an electronic module;

[0019] Figure 4A yes Figure 1 A schematic diagram illustrating the time-temperature relationship of the method;

[0020] Figure 4B yes Figure 1 A diagram illustrating the time-pressure relationship of the method.

[0021] Explanation of reference numerals in the attached figures

[0022] 10: Electronic module;

[0023] 12: Circuit board;

[0024] 13-17: Electronic components;

[0025] 20, 22: Protective materials;

[0026] 25: Protective film;

[0027] 30: Cavity;

[0028] 40: Air bubbles;

[0029] 100: A method for forming a protective film on an electronic module;

[0030] 110-150: Steps. Detailed Implementation

[0031] Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same component reference numerals are used in the drawings and description to denote the same or similar parts.

[0032] Figure 1 This is a schematic diagram of the steps of a method for forming a protective film on an electronic module according to an embodiment of the present invention. Figures 2A to 2C yes Figure 1 A schematic diagram of one of the processes for forming a protective film on an electronic module. Figures 3A to 3C yes Figure 1 Another schematic diagram of the process for forming a protective film on an electronic module. Figure 4A yes Figure 1 A schematic diagram illustrating the time-temperature relationship of the method. Figure 4B yes Figure 1 A diagram illustrating the time-pressure relationship of the method.

[0033] Please refer to the following first. Figure 1 , Figure 2A and Figure 3A The method 100 for forming a protective film on an electronic module in this embodiment includes the following steps. First, step 110 is performed, in which the electronic module 10 and the protective material 20 placed on the electronic module 10 are... Figure 2A ),twenty two( Figure 3A The protective materials 20 and 22 are placed inside the cavity 30, where they are in contact with the electronic module 10.

[0034] exist Figure 2A In the circuit, the electronic module 10 includes a circuit board 12 and a plurality of electronic components 13-17 disposed on the circuit board 12, the electronic components 13-17 having different heights. A protective material 20 is placed above these electronic components 13-17, and the area of ​​the protective material 20 does not exceed the area of ​​the circuit board 12.

[0035] Figure 3A Implementation examples and Figure 2A The difference in the embodiments is that, in Figure 3A In this process, the protective material 22 can be multi-layered, resulting in a large overall thickness of these protective materials 22.

[0036] Next, step 120 is performed, in which the protective materials 20 and 22 inside the cavity 30 are subjected to a first heating process to soften the protective materials 20 and 22 placed on the electronic module 10, and the cavity 30 is subjected to a first pressurization process, wherein the pressure of the first pressurization process is greater than 1 atmosphere. This first heating process softens the protective materials 20 and 22. Figure 3B The multi-layered protective material 22 will fuse together as one. For example... Figure 2B , Figure 3B As shown, the softened protective materials 20 and 22 collapse to the contact circuit board 12, and multiple bubbles 40 form between the protective materials 20 and 22 and the electronic components 13-17. A first boost process is used to cause the bubbles 40 between the electronic module 10 and the protective materials 20 and 22 to escape from... Figure 2B , Figure 3B The position gradually moves upward to be close to the surface of the protective materials 20 and 22.

[0037] In this embodiment, the temperature of the first heating program is, for example, 130 degrees Celsius, and the pressure is, for example, 11 atmospheres, which is a pressure difference of 10 atmospheres with the external pressure. The first pressurization program can last for 10 to 25 minutes. Of course, the values ​​of the first pressurization program and the first heating program are not limited to these.

[0038] Next, in step 130, after softening the protective materials 20 and 22, the first heating program is maintained, and the cavity 30 is subjected to a depressurization oscillation program, which includes alternating the pressure of the cavity 30 between multiple low pressures below 1 atmosphere.

[0039] like Figure 4B As shown, the pressure first drops to below 1 atmosphere, and then oscillates to change its magnitude while remaining below 1 atmosphere. Next, the pressure is increased to a high pressure, then decreased to below 1 atmosphere again, and this oscillation is repeated multiple times. In other words, in this embodiment, the cavity 30 undergoes the first pressurization and depressurization oscillation process repeatedly. Of course, whether or not this process is repeated, and the number of repetitions, is not limited by the accompanying drawings.

[0040] Specifically, by Figure 4B As can be seen, in this embodiment, three pressure reduction oscillation procedures are performed. In each pressure reduction oscillation procedure, the pressure oscillates between the base low pressure and multiple variable low pressures. The pressure of the base low pressure is greater than these variable low pressures, which gradually decrease over time. These variable low pressures alternate with the base low pressure, and in the case of two adjacent time sequences of these variable low pressures, the pressure will first return to the base low pressure.

[0041] For the first oscillation, the pressure-time relationship is shown in Table 1 below. The cavity 30 remains at each of these varying low pressures for a longer period than it remains at the base low pressure. Specifically, in this embodiment, the base low pressure is 380 torr for 0 seconds, and the varying low pressure gradually decreases from 270 torr to 210 torr, each lasting 30 seconds. During this process, the bubbles 40 within the protective materials 20 and 22, near their surfaces, will rupture due to the pressure changes within the cavity 30.

[0042] stress (torr) Time (seconds) 270 30 380 0 250 30 380 0 230 30 380 0 210 30 380 0 210 30 750 0

[0043] Table 1

[0044] Next, the cavity 30 undergoes a second first pressurization procedure. For example, the pressure of the second first pressurization procedure is 10 atmospheres and it lasts for six minutes. In this embodiment, the pressure of the second first pressurization procedure is the same as the pressure of the first first pressurization procedure. However, in other embodiments, the pressure of the second first pressurization procedure may be different from the pressure of the first first pressurization procedure.

[0045] Next, a second pressure-reducing oscillation process is performed. The purpose of this second process is to allow the bubbles 40 that did not burst during the first process to break. The pressure differentials in the second process are greater than those in the first. Due to the material properties of the protective materials 20 and 22, the viscosity of the curing adhesive increases over time at the same temperature, making it more difficult for bubbles 40 to break. Therefore, increasing the pressure differential increases the magnitude of the volume change of bubbles 40, which helps them break.

[0046] The pressure and time of the second pressure reduction and oscillation procedure are shown in Table 2 below. In this embodiment, the base low pressure is 380 torr and lasts for 0 seconds. The variable low pressure gradually decreases from 210 torr to 130 torr, and each time lasts for 30 seconds.

[0047] stress (torr) Time (seconds) 210 30 380 0 190 30 380 0 170 30 380 0 150 30 380 0 130 30 750 0

[0048] Table 2

[0049] Next, the chamber 30 undergoes a third first pressurization procedure. For example, the pressure of the third first pressurization procedure is 10 atmospheres and lasts for six minutes. Then, a third depressurization oscillation procedure is performed. The pressure and time of the third depressurization oscillation procedure are shown in Table 3 below. In this embodiment, the base low pressure is 380 torr and lasts for 0 seconds; the changing low pressure gradually decreases from 130 torr to 30 torr, with each decrease lasting 40 seconds.

[0050] stress (torr) Time (seconds) 130 40 380 0 100 40 380 0 70 40 380 0 30 40 750 0

[0051] Table 3

[0052] Next, the cavity 30 undergoes a fourth first pressurization procedure. The pressure of this fourth first pressurization procedure is 10 atmospheres and lasts for six minutes. Following this, a depressurization procedure is performed. In this embodiment, the pressure of the depressurization procedure is lower than the pressure of the depressurization oscillation procedure, and the cavity 30 remains at the pressure of the depressurization procedure for a longer time than it remains at the pressure of the depressurization oscillation procedure. Specifically, the pressure of the depressurization procedure is 30 torr, and the time is 300 seconds. In this step, using a relatively small pressure (a large negative pressure value) close to vacuum for a longer period allows the remaining bubbles 40 to expand directly until they burst.

[0053] Next, in step 140, the first heating program is maintained, and a second pressurization program is applied to the cavity 30, wherein the pressure of the second pressurization program is less than the pressure of the first pressurization program but greater than 1 atmosphere. In this embodiment, the second pressurization program is, for example, first pressurizing to 2 atmospheres for 20 minutes, and then pressurizing to 3 atmospheres for 5 minutes. In the preceding steps, since the rupture of the bubbles 40 would cause the surfaces of the protective materials 20 and 22 to become uneven, using a lower pressure (2 to 3 atmospheres) can be used to smooth the surfaces of the protective materials 20 and 22 without being too high and inhibiting the flow of the protective materials 20 and 22.

[0054] Furthermore, since the viscosity of protective materials 20 and 22 gradually increases over time at a certain temperature, the second pressurization process, consisting of two pressurization steps, is more conducive to smoothing the surfaces of protective materials 20 and 22. Of course, in other embodiments, this can be accomplished with only one pressurization step. Alternatively, it can be accomplished with more steps.

[0055] Next, in step 150, a second heating process is performed on the protective materials 20 and 22 inside the cavity 30 to solidify the protective materials 20 and 22 covering the electronic module 10, as shown in step 150. Figure 2C and Figure 3C A protective film 25 is formed covering the electronic module 10 as shown. The protective materials 20 and 22 are, for example, thermosetting materials, and in the second heating process, the temperature can be raised to 175 degrees Celsius to cure the protective materials 20 and 22. During the second heating process, a third pressurization process is simultaneously applied to the cavity 30. The pressure in this stage can be 11 atmospheres, and the duration can be 30 to 60 minutes, or the minimum curing time required for the protective materials 20 and 22.

[0056] Finally, as Figure 4A and Figure 4B The temperature and pressure are reduced during this stage. The temperature is 80 degrees Celsius, the pressure is 6 atmospheres, and the time is 25 minutes, but this is not a limitation.

[0057] exist Figure 2C In this context, the surface contour of the protective film 25 covering the electronic module 10 conforms to the contours of these electronic components 13-17. Figure 3C In this case, because the protective film 25 is relatively thick, the surface of the protective film 25 covering the electronic module 10 can be planar, and not conform to the contours of these electronic components 13-17. Furthermore, due to... Figure 2C and Figure 3C It is evident that the protective film 25 will only cover the top surface of the circuit board 12 and will not flow onto the sides or back of the circuit board 12.

[0058] It is worth mentioning that, in order to produce Figure 3C The surface of the protective film 25 is planar. Because the protective material 22 initially used has many layers or is relatively thick, it is difficult to remove air bubbles 40. The method 100 for forming the protective film 25 on the electronic module 10 in this embodiment effectively removes air bubbles 40 through a voltage reduction and oscillation process, thus completing the process. Figure 3C The structure.

[0059] In summary, the method for forming a protective film on an electronic module according to the present invention involves first heating a protective material within a cavity to soften the material placed on the electronic module, followed by a first pressurization process to move air bubbles between the electronic module and the protective material to near the surface of the protective material. Next, while maintaining the first heating process, a depressurization oscillation process is performed on the cavity, alternating between multiple low pressures below 1 atmosphere. During this depressurization oscillation process, air bubbles within the protective material near the surface rupture due to the pressure changes within the cavity. Then, while maintaining the first heating process, a second pressurization process is performed on the cavity, with a pressure less than that of the first pressurization process but greater than 1 atmosphere. During the second pressurization process, the softened protective material can be flattened under pressure. Finally, a second heating process is performed on the protective material within the cavity to solidify the protective material covering the electronic module, forming a protective film covering the electronic module.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for forming a protective film on an electronic module, characterized in that, include: The electronic module and the protective material placed on the electronic module are placed inside the cavity, wherein the protective material is in contact with the electronic module. The protective material inside the cavity is subjected to a first heating process to soften the protective material placed on the electronic module, and the cavity is subjected to a first pressurization process, wherein the pressure of the first pressurization process is greater than 1 atmosphere. After the protective material is softened, the first heating program is maintained, and the cavity is subjected to a depressurization oscillation program, wherein the depressurization oscillation program includes alternately changing the pressure of the cavity between multiple low pressures below 1 atmosphere. The first heating program is maintained, and the cavity is subjected to a second pressurization program, wherein the pressure of the second pressurization program is less than the pressure of the first pressurization program and greater than 1 atmosphere; as well as A second heating process is applied to the protective material within the cavity to solidify the protective material covering the electronic module, thereby forming the protective film covering the electronic module. In the aforementioned pressure reduction and oscillation process, the multiple low pressures include a base low pressure and multiple variable low pressures. The pressure of the base low pressure is greater than that of the multiple variable low pressures. The multiple variable low pressures gradually decrease over time. The multiple variable low pressures alternate with the base low pressure, such that between two adjacent time sequences of the multiple variable low pressures, the pressure will first return to the base low pressure.

2. The method for forming a protective film on an electronic module according to claim 1, characterized in that, The cavity is maintained at each of the plurality of varying low pressures for a longer period than the cavity is maintained at the base low pressure.

3. The method for forming a protective film on an electronic module according to claim 1, characterized in that, After the first boosting procedure and the depressurization oscillation procedure are performed, and before the second boosting procedure is performed, the procedure further includes: repeating the first boosting procedure and the depressurization oscillation procedure on the cavity.

4. The method for forming a protective film on an electronic module according to claim 3, characterized in that, The pressure difference of the plurality of low pressures in the second depressurization oscillation procedure is greater than the pressure difference of the plurality of low pressures in the first depressurization oscillation procedure.

5. The method for forming a protective film on an electronic module according to claim 3, characterized in that, After repeatedly performing the first pressurization procedure and the depressurization oscillation procedure on the cavity, and before performing the second pressurization procedure, the method further includes performing the first pressurization procedure and the depressurization procedure on the cavity, wherein the pressure of the depressurization procedure is less than the pressure of the depressurization oscillation procedure.

6. The method for forming a protective film on an electronic module according to claim 5, characterized in that, The time the cavity remains at the pressure in the depressurization process is longer than the time the cavity remains at the pressure in the depressurization oscillation process.

7. The method for forming a protective film on an electronic module according to claim 3, characterized in that, The pressure of the first boosting procedure in the first instance is the same as or different from the pressure of the first boosting procedure in the second instance.

8. The method for forming a protective film on an electronic module according to claim 1, characterized in that, During the second heating process, the cavity is simultaneously subjected to a third pressurization process.

9. The method for forming a protective film on an electronic module according to claim 1, characterized in that, The electronic module includes multiple electronic components, and the surface contour of the protective film covering the electronic module conforms to the contour of the multiple electronic components.

10. The method for forming a protective film on an electronic module according to claim 1, characterized in that, The electronic module includes multiple electronic components, and the surface of the protective film covering the electronic module is planar and not conformal to the contours of the multiple electronic components.

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