A method for selective sputtering in SIP packaging

Abstract

The present invention provides a method for selective sputtering in SIP packaging, and the method includes the following steps: (1) coating a pyrolytic adhesive on the non-sputtering area of the SIP packaging module; (2) curing the pyrolytic adhesive in step (1); (3) performing sputtering to form an electromagnetic shielding layer in the sputtering area; (4) after sputtering is completed, heating up to make the pyrolytic adhesive fall off, thus completing the selective sputtering in SIP packaging. The method provided by the present invention can achieve automated operation, precisely locate the non-sputtering area, and greatly reduce manual labor, with relatively low process costs, and is simple and practical.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor packaging, and relates to a packaging method, in particular to a method for selective sputtering in SIP packaging. Background Art

[0002] A System In a Package (SIP) is a single standard package that assembles multiple active electronic components with different functions, optional passive electronic components, and components such as MEMS or optical devices together to achieve a certain function. From an architectural perspective, SIP integrates multiple functional chips, such as processor, memory, and other functional chips, within a single package to achieve a basically complete function. Different from a System-on-Chip (SOC), SIP packaging uses different chips for side-by-side or stacked packaging, while SOC is a highly integrated chip product.

[0003] Electronic devices are developing towards miniaturization. Therefore, ultra-thin and highly integrated SIP packaging is becoming increasingly important. However, when the chip spacing in SIP is too close, crosstalk will occur between adjacent chips. Especially for high-frequency analog chips, their reliability will be affected by electromagnetic interference.

[0004] CN 1849052A discloses an electromagnetic interference shielding package, which includes a substrate on which electronic components and a plurality of pads are provided; a metal cover having a bottom and side walls perpendicular thereto, and a plurality of pads are provided on the side walls; the metal cover is placed on the substrate, and the pads on the metal cover adhere to the corresponding pads on the substrate, and the metal cover covers the above-mentioned electronic components. A plastic encapsulation colloid is provided in the gap between the electronic components, the metal cover and the substrate. The above technical solution uses a metal cover as a shielding layer for electronic components. However, voids are easily generated during the injection molding of the inner cavity of the metal cover, and the reliability of the product is affected to a certain extent; moreover, the metal cover has a certain thickness, increasing the height of the entire module, which is not suitable for high I / O density packaging; in addition, there is also a serious thermal mismatch problem between the metal cover and the substrate, and the thermal cycle during device operation will generate large stresses, resulting in shielding failure.

[0005] The sputtering method realizes electromagnetic shielding by sputtering a metal layer on the surface of electronic components. Since the sputtered layer is extremely thin, it conforms to the miniaturization and ultra-thin design trends of SIP packaging, making its application more and more extensive. However, the sputtering method cannot achieve selective overplating, but can only sputter on the entire surface of the module. However, during the SIP packaging process, selective packaging and electromagnetic shielding are often required.

[0006] For example, CN 111415913A discloses a selectively packaged SIP module with an electromagnetic shielding structure and a preparation method thereof. The selectively packaged SIP module includes: a substrate, a plastic encapsulation layer, a metal cover, and a shielding layer. One side of the substrate is provided with at least one encapsulation area and one non-encapsulation area; at least one first electronic component is mounted on the encapsulation area of the substrate; the plastic encapsulation layer covers the first electronic components in the encapsulation area; the metal cover is installed in the non-encapsulation area, and the metal cover has a first side wall that fits against the side surface of the plastic encapsulation layer; the shielding layer covers the outer surface of the plastic encapsulation layer and the side surface of the substrate. In the prior art during selective packaging, it is mostly by designing a selective packaging mold to form a non-encapsulation area after packaging, and then selectively coating the shielding layer. Then the selective packaging mold is a special mold, which increases the cost.

[0007] Moreover, before selectively coating the shielding layer, it is necessary to protect the non-coated area to avoid over-plating caused by the shielding material flowing in. Applying tape or setting a protective cover is the main current protection method. However, the applied tape or the set protective cover is not firm, and the risk of over-plating during the sputtering process is relatively high. Also, for the technical solution of setting a protective cover, after the sputtering is completed, the protective cover needs to be removed.

[0008] Therefore, the method provided by the prior art requires manual mounting, and the process is complex. Limited by the size and precision of the tape, protective cover, or metal cover, it is also impossible to protect complex shapes or fine areas. Therefore, it is necessary to provide a method for selective sputtering in SIP packaging that can perform refined operations and has a simple process. Summary of the Invention

[0009] The purpose of the present invention is to provide a method for selective sputtering in SIP packaging, particularly a method for selective sputtering in SIP packaging based on a thermally decomposable adhesive. By using the thermally decomposable adhesive to replace the conventional tape, protective cover, or metal cover in the art, the present invention can achieve the protection of complex shapes and fine areas, and achieve the purpose of selective sputtering with a simple process.

[0010] To achieve the purpose of this invention, the present invention adopts the following technical solutions:

[0011] The present invention provides a method for selective sputtering in SIP packaging, and the method includes the following steps:

[0012] (1) Coating a thermally decomposable adhesive on the non-sputtering area of the SIP packaging module;

[0013] (2) Curing the thermally decomposable adhesive in step (1);

[0014] (3) Performing sputtering to form an electromagnetic shielding layer in the sputtering area;

[0015] (4) After sputtering, heat up to make the thermolytic adhesive fall off, completing the selective sputtering of the SIP package.

[0016] In the present invention, by coating a thermolytic adhesive in the non-sputtering area and using the thermolytic adhesive to replace traditional tapes, protective covers or metal covers, it can be applied to irregular non-sputtering areas. And the cured thermolytic adhesive can automatically fall off from the protected area by heating up, without manual removal, achieving the purpose of selective sputtering with a simple process.

[0017] Preferably, the method of coating the thermolytic adhesive in step (1) includes any one or a combination of at least two of spraying, dispensing or screen printing.

[0018] The thermolytic adhesive is applicable to the methods of spraying, dispensing or screen printing, so it can be used for protecting complex shapes or precision areas and can achieve precise positioning. At the same time, it automatically falls off after heating up, effectively reducing the manual removal process; meanwhile, the coating of the thermolytic adhesive does not require the setting of additional plastic seals or metal covers, simplifying the process.

[0019] Preferably, by weight, the thermolytic adhesive includes:

[0020]

[0021]

[0022] By weight, the weight fraction of polybutadiene acrylate oligomer in the thermolytic adhesive is 10 - 60 parts, for example, it can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts or 60 parts, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0023] By weight, the weight fraction of thermolytic filler in the thermolytic adhesive is 10 - 50 parts, for example, it can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts or 50 parts, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0024] By weight, the weight fraction of epoxy-modified acrylic resin in the thermolytic adhesive is 10 - 40 parts, for example, it can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts or 40 parts, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0025] Based on parts by weight, the weight parts of acrylate monomers in the pyrolytic adhesive are 20 - 40 parts, for example, it can be 20 parts, 25 parts, 30 parts, 35 parts or 40 parts, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0026] Based on parts by weight, the weight parts of photoinitiator in the pyrolytic adhesive are 1 - 5 parts, for example, it can be 1 part, 2 parts, 3 parts, 4 parts or 5 parts, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0027] Based on parts by weight, the weight parts of surfactant in the pyrolytic adhesive are 3 - 10 parts, for example, it can be 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0028] Preferably, the weight - average molecular weight of the polybutadiene acrylate oligomer is 5000 - 10000, for example, it can be 5000, 6000, 7000, 8000, 9000 or 10000, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0029] Preferably, the pyrolytic release filler is a heat - foaming microsphere with an expansion ratio of 20 - 60 times, and the expansion ratio of the heat - generating and expanding microsphere is 20 - 60 times, for example, it can be 20 times, 30 times, 40 times, 50 times or 60 times, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0030] Preferably, the initial average particle size of the pyrolytic release filler is 5 - 100 μm, for example, it can be 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0031] Preferably, the starting foaming temperature of the pyrolytic release filler is 180 - 250 °C, for example, it can be 180 °C, 200 °C, 210 °C, 220 °C, 240 °C or 250 °C, but not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0032] Preferably, the acrylate monomer includes any one or a combination of at least two of methacrylate, isobornyl acrylate, glycidyl methacrylate, 2 - hydroxyethyl acrylate, 2 - hydroxypropyl acrylate, alkoxydodecyl acrylate, triethylene glycol ethyl ether methacrylate, acrylamide or hydroxyacrylamide.

[0033] Preferably, the photoinitiator includes any one or a combination of at least two of 1-hydroxycyclohexyl phenyl ketone, 2,4,6-(trimethylbenzoyl) diphenylphosphine oxide, 2-methyl-1-(4-methylthiophenyl)-2-morpholin-1-propanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinobenzylphenyl) butanone, methyl benzoylformate, phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 2-isopropylthioxanthone, benzoin dimethyl ether, dimethylbenzil ketal or benzophenone.

[0034] Preferably, the surfactant includes any one or a combination of at least two of fatty alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether or alkylphenol polyoxyethylene ether.

[0035] In the present invention, since the sputtering process will undergo extremely high temperatures, up to 160 °C at most, the selected thermal decomposition adhesive needs to have higher heat resistance than ordinary thermal decomposition adhesives. After the thermal decomposition adhesive provided by the present invention is cured, at a temperature not exceeding 160 °C, the thermal decomposition adhesive will neither lose adhesion and fall off, nor soften and deform, nor embrittle and crack, let alone undergo thermal decomposition. The present invention creatively uses polybutadiene acrylate oligomer, thermal decomposition filler, epoxy-modified acrylate resin and acrylate monomer as the main body, and cooperates with a photoinitiator and a surfactant. Under the condition of reasonable proportion of each component, a suitable thermal decomposition adhesive with excellent performance is obtained. After the adhesive is cured, it can fully meet the high temperature resistance requirements at 160 °C and below, and can also automatically expand and fall off as a whole at 200 - 250 °C without any residual glue left.

[0036] Preferably, the curing method in step (2) includes ultraviolet curing.

[0037] After curing according to step (2) of the present invention, the thermal decomposition adhesive forms a thermal decomposition UV glue layer.

[0038] Preferably, the temperature of the temperature rise in step (4) is 200 - 250 °C, for example, it can be 200 °C, 210 °C, 220 °C, 230 °C, 240 °C or 250 °C, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0039] The thermal decomposition adhesive provided by the present invention will expand when heated in the range of 200 - 250 °C, completely detach from the surface of the attached device without any residue, and this process does not require manual operation.

[0040] As a preferred technical solution of the method of the present invention, the method includes the following steps:

[0041] (1) Apply a pyrolytic adhesive on the non-sputtering area of the SIP packaging module; the method of applying the pyrolytic adhesive includes any one or a combination of at least two of spraying, dispensing, or screen printing;

[0042] (2) Cure the pyrolytic adhesive in step (1) by ultraviolet light;

[0043] (3) Perform sputtering to form an electromagnetic shielding layer in the sputtering area;

[0044] (4) After sputtering, heat up to 200 - 250 °C to make the pyrolytic adhesive fall off, completing the selective sputtering of the SIP packaging.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] (1) The method of selective sputtering for SIP packaging of the present invention can achieve the purpose of selective sputtering only through four steps: applying pyrolytic adhesive, curing, sputtering, and pyrolysis. The process is simple and has high efficiency;

[0047] (2) The present invention uses a pyrolytic adhesive to replace traditional tapes or packaging molds, and can use a refined dispensing method to temporarily protect complex shapes and fine areas, and accurately position, so as to achieve the purpose of selective sputtering;

[0048] (3) The pyrolytic adhesive used in the present invention is mainly composed of polybutadiene acrylate oligomer, pyrolytic filler, epoxy-modified acrylate resin, and acrylate monomer, and is combined with a photoinitiator and a surfactant. The proportion of each component is reasonable and the performance is excellent. After curing, the adhesive can fully meet the high-temperature resistance requirements at 160 °C and below, and can also automatically expand at 200 - 250 °C and fall off as a whole, without any residual glue;

[0049] (3) The present invention does not require designing special packaging molds or metal covers for selective packaging, nor does it need to perform cutting or laser processes to remove after sputtering. It not only shortens the manufacturing process steps of the entire SIP module, but also effectively reduces the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figures 1 - 3 It is a schematic process flow diagram of the method of the present invention.

[0051] Among them: 1, chip; 2, pad; 3, pyrolytic UV glue layer; 4, electromagnetic shielding layer. DETAILED DESCRIPTION OF THE INVENTION

[0052] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0053] The present invention provides a method for selective sputtering in SIP packaging, and the method comprises the following steps:

[0054] (1) Refer to Figure 1 . On the PCB, there are arranged chip 1 and pad 2. Pad 2 does not require electromagnetic shielding and is the area that does not need to be sputtered, while chip 1 is the area that needs to be sputtered to form electromagnetic shielding. Apply a pyrolytic adhesive above pad 2;

[0055] (2) Photocure the pyrolytic adhesive in step (1), and the pyrolytic adhesive forms a pyrolytic UV glue layer 3 covering pad 2;

[0056] (3) Sputter the surface of the module to form an electromagnetic shielding layer 4 in the sputtering area. As Figure 2 described, the surface of the entire SIP module is plated with the electromagnetic shielding layer 4, and at this time, the pyrolytic UV glue layer 3 formed by curing does not undergo pyrolysis or deformation;

[0057] (4) As Figure 3 shown, after sputtering, the SIP module is heated to make the pyrolytic UV glue layer 3 formed by curing the pyrolytic adhesive expand and fall off, and at the same time, take away the attached electromagnetic shielding layer 4 on it, so that pad 2 is exposed without affecting the existence of the electromagnetic shielding layer 4 in other areas, thus completing the selective sputtering in SIP packaging.

[0058] Example 1

[0059] The present example provides a method for selective sputtering in SIP packaging, and the method comprises the following steps:

[0060] (1) Coat a pyrolytic adhesive in the non-sputtering area of the SIP packaging module; the method of coating the pyrolytic adhesive is spray gluing;

[0061] (2) Use a UV-LED lamp to irradiate the spray-glued area to fully cure the pyrolytic adhesive in step (1) and form a pyrolytic UV glue layer;

[0062] (3) Perform metal sputtering to form an electromagnetic shielding layer in the sputtering area; during the metal sputtering process, the pyrolytic adhesive does not undergo pyrolysis or deformation;

[0063] (4) After sputtering, heat up to 200 °C, the pyrolytic UV glue layer expands and falls off, taking away the attached electromagnetic shielding layer, thus completing the selective sputtering in SIP packaging.

[0064] The pyrolytic adhesive in this example comprises the following components:

[0065]

[0066]

[0067] It can be seen through a 40 - fold microscope that a complete electromagnetic shielding layer has formed in the sputtering area, while there is no residual glue and no over - plating problem in the non - sputtering area; the swelling and shedding in step (4) only takes 12 minutes, and the peeling integrity of the pyrolytic UV glue layer is 100%.

[0068] Example 2

[0069] This example provides a method for selective sputtering in SIP packaging, and the method includes the following steps:

[0070] (1) Coat a pyrolytic adhesive on the non - sputtering area of the SIP packaging module; the method of coating the pyrolytic adhesive is spraying glue;

[0071] (2) Use a UV - LED lamp to irradiate the area where the glue is sprayed to fully cure the pyrolytic adhesive described in step (1);

[0072] (3) Perform metal sputtering to form an electromagnetic shielding layer in the sputtering area; during the metal sputtering process, the pyrolytic adhesive does not undergo pyrolysis or deformation;

[0073] (4) After the sputtering is completed, heat up to 200 °C, and the pyrolytic adhesive swells and falls off, taking away the electromagnetic shielding layer attached to it, thus completing the selective sputtering of the SIP packaging.

[0074] The pyrolytic adhesive described in this example includes the following components:

[0075]

[0076]

[0077] It can be seen through a 40 - fold microscope that a complete electromagnetic shielding layer has formed in the sputtering area, while there is no residual glue and no over - plating problem in the non - sputtering area; the swelling and shedding in step (4) only takes 10 minutes, and the peeling integrity of the pyrolytic UV glue layer is 100%.

[0078] Example 3

[0079] This example provides a method for selective sputtering in SIP packaging, and the method includes the following steps:

[0080] (1) Coat a pyrolytic adhesive on the non - sputtering area of the SIP packaging module; the method of coating the pyrolytic adhesive is spraying glue;

[0081] (2) Use a UV - LED lamp to irradiate the area where the glue is sprayed to fully cure the pyrolytic adhesive described in step (1);

[0082] (3) Perform metal sputtering to form an electromagnetic shielding layer in the sputtering area; during the metal sputtering process, the pyrolytic adhesive does not undergo pyrolysis or deformation;

[0083] (4) After the sputtering is completed, the temperature is raised to 200 °C, and the pyrolytic adhesive expands and falls off, carrying away the electromagnetic shielding layer attached thereto, thus completing the selective sputtering of the SIP package.

[0084] The pyrolytic adhesive described in this embodiment includes the following components:

[0085]

[0086] Observed through a 40 - fold microscope, a complete electromagnetic shielding layer is formed in the area to be sputtered, while there is no residual glue in the non - sputtered area, nor is there any over - sputtering problem; the expansion and falling off described in step (4) only takes 14 minutes, and the peeling integrity of the pyrolytic UV glue layer is 100%.

[0087] Example 4

[0088] This embodiment provides a method for selective sputtering of SIP packages, and the method includes the following steps:

[0089] (1) Coat a pyrolytic adhesive on the non - sputtered area of the SIP package module; the method of coating the pyrolytic adhesive is spraying glue.

[0090] (2) Use a UV - LED lamp to irradiate the area where the glue is sprayed, so that the pyrolytic adhesive described in step (1) is fully cured.

[0091] (3) Conduct metal sputtering to form an electromagnetic shielding layer in the sputtered area; during the metal sputtering process, the pyrolytic adhesive does not undergo pyrolysis or deformation.

[0092] (4) After the sputtering is completed, the temperature is raised to 200 °C, and the pyrolytic adhesive expands and falls off, carrying away the electromagnetic shielding layer attached thereto, thus completing the selective sputtering of the SIP package.

[0093] The pyrolytic adhesive described in this embodiment includes the following components:

[0094]

[0095] Observed through a 40 - fold microscope, a complete electromagnetic shielding layer is formed in the area to be sputtered, while there is no residual glue in the non - sputtered area, nor is there any over - sputtering problem; the expansion and falling off described in step (4) only takes 16 minutes, and the peeling integrity of the pyrolytic UV glue layer is 100%.

[0096] Example 5

[0097] This embodiment provides a method for selective sputtering of SIP packages, and the method includes the following steps:

[0098] (1) Coat a pyrolytic adhesive on the non - sputtered area of the SIP package module; the method of coating the pyrolytic adhesive is spraying glue.

[0099] (2) Irradiate the sprayed glue area with a UV-LED lamp to fully cure the pyrolytic adhesive described in step (1);

[0100] (3) Perform metal sputtering to form an electromagnetic shielding layer in the sputtering area; during the metal sputtering process, the pyrolytic adhesive does not undergo pyrolysis or deformation;

[0101] (4) After the sputtering is completed, heat up to 200 °C, and the pyrolytic adhesive expands and falls off, taking away the electromagnetic shielding layer attached to it, and completing the selective sputtering of the SIP package.

[0102] The pyrolytic adhesive described in this embodiment includes the following components:

[0103]

[0104] It can be seen through a 40-fold microscope that a complete electromagnetic shielding layer has been formed in the area to be sputtered, and there is no residual glue or over-sputtering problem in the non-sputtered area; the expansion and falling off described in step (4) only takes 8 minutes, and the peeling integrity of the pyrolytic UV glue layer is 100%.

[0105] Example 6

[0106] This embodiment provides a method for selective sputtering of SIP packages, and the method includes the following steps:

[0107] (1) Coat the pyrolytic adhesive in the non-sputtered area of the SIP package module; the method of coating the pyrolytic adhesive is dispensing;

[0108] (2) Irradiate the sprayed glue area with a UV-LED lamp to fully cure the pyrolytic adhesive described in step (1);

[0109] (3) Perform metal sputtering to form an electromagnetic shielding layer in the sputtering area; during the metal sputtering process, the pyrolytic adhesive does not undergo pyrolysis or deformation;

[0110] (4) After the sputtering is completed, heat up to 230 °C, and the pyrolytic adhesive expands and falls off, taking away the electromagnetic shielding layer attached to it, and completing the selective sputtering of the SIP package.

[0111] The components of the pyrolytic adhesive described in this embodiment are the same as those in Example 1.

[0112] It can be seen through a 40-fold microscope that a complete electromagnetic shielding layer has been formed in the area to be sputtered, and there is no residual glue or over-sputtering problem in the non-sputtered area; the expansion and falling off described in step (4) only takes 8 minutes, and the peeling integrity of the pyrolytic UV glue layer is 100%.

[0113] Example 7

[0114] This embodiment provides a method for selective sputtering in SIP packaging. The method includes the following steps:

[0115] (1) Coat a pyrolytic adhesive on the non-sputtering area of the SIP packaging module; the method of coating the pyrolytic adhesive is screen printing;

[0116] (2) Use a UV-LED lamp to irradiate the area where the adhesive is sprayed to fully cure the pyrolytic adhesive described in step (1);

[0117] (3) Perform metal sputtering to form an electromagnetic shielding layer in the sputtering area; during the metal sputtering process, the pyrolytic adhesive does not undergo pyrolysis or deformation;

[0118] (4) After the sputtering is completed, heat up to 250 °C, and the pyrolytic adhesive expands and falls off, taking away the electromagnetic shielding layer attached to it, and completing the selective sputtering of the SIP packaging.

[0119] The components of the pyrolytic adhesive in this embodiment are the same as those in Embodiment 1.

[0120] It can be seen through a 40-fold microscope that a complete electromagnetic shielding layer is formed in the area to be sputtered, and there is no residual glue or overplating problem in the non-sputtering area; the expansion and falling off described in step (4) only takes 4 minutes, and the peeling integrity of the pyrolytic UV glue layer is 100%.

[0121] In summary, the method for selective sputtering in SIP packaging according to the present invention can achieve the purpose of selective sputtering only through four steps: coating, curing, sputtering, and pyrolysis of the pyrolytic adhesive. The process is simple and has high efficiency; the present invention uses a pyrolytic adhesive to replace traditional tapes or packaging molds, and can use a fine dispensing method to temporarily protect complex shapes and fine areas, and accurately position, so as to achieve the purpose of selective sputtering; the present invention does not require the design of special packaging molds or metal covers for selective packaging, nor does it require cutting or laser processes to remove after sputtering, which not only shortens the manufacturing process steps of the entire SIP module, but also effectively reduces the production cost.

[0122] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for selective sputtering in SIP packaging, characterized in that, the method comprises the following steps: (1) Coating a pyrolytic adhesive on the non-sputtering area of the SIP packaging module; The method of coating the pyrolytic adhesive includes any one or a combination of at least two of spraying glue, dispensing glue or screen printing; (2) Curing the pyrolytic adhesive in step (1); The curing method includes ultraviolet curing; (3) Performing sputtering to form an electromagnetic shielding layer in the sputtering area; (4) After sputtering is completed, heating is carried out to make the pyrolytic adhesive fall off, and the selective sputtering of the SIP packaging is completed; The heating temperature is 200-250°C; By weight, the pyrolytic adhesive is composed of the following components: Polybutadiene acrylic oligomer 10-60 parts Pyrolytic adhesion filler 10-50 parts Epoxy-modified acrylic resin 10-40 parts Acrylate monomer 20-40 parts Photoinitiator 1-5 parts Surfactant 3-10 parts; After the pyrolytic adhesive is cured, it does not pyrolyze at a temperature not exceeding 160°C, and automatically expands and falls off as a whole at 200-250°C.

2. The method according to claim 1, characterized in that, the weight average molecular weight of the polybutadiene acrylic oligomer is 5000-10000.

3. The method according to claim 1, characterized in that, the pyrolytic adhesion filler is a heat-expandable microsphere with an expansion multiple of 20-60 times.

4. The method according to claim 1, characterized in that, the initial average particle size of the pyrolytic adhesion filler is 5-100μm.

5. The method according to claim 1, characterized in that, the foaming temperature of the pyrolytic adhesion filler is 180-250°C.

6. The method according to claim 1, characterized in that, the acrylate monomer includes any one or a combination of at least two of methyl methacrylate, isobornyl acrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, alkoxydodecyl acrylate, triethylene glycol ethyl ether methacrylate, acrylamide or hydroxyacrylamide.

7. The method according to claim 1, characterized in that, the photoinitiator includes any one or a combination of at least two of 1-hydroxycyclohexyl phenyl ketone, 2,4,6-(trimethylbenzoyl) diphenyl phosphine oxide, 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-phenylbenz-2-dimethylamine-1-(4-morpholinobenzphenyl) butanone, methyl benzoylformate, phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, 2-isopropylthioxanthone, benzoin dimethyl ether, dimethylbenzil ketal or benzophenone.

8. The method according to claim 1, characterized in that, the surfactant includes any one or a combination of at least two of fatty alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether or alkylphenol polyoxyethylene ether.

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