Protecting electronic systems from electromagnetic interference (EMI) has become a hot topic. Technological advances in 5G standards, wireless charging for mobile electronics, antenna integration into the chassis, and the introduction of System in Package (SiP) are driving the need for better EMI shielding and isolation in component packages and larger modular applications. For conformal shielding, EMI shielding materials for the outer surfaces of the package are mainly deposited using physical vapor deposition (PVD) processes using prepackaging technology for internal packaging applications. However, the scalability and cost issues of spray technology, as well as advances in consumables, are leading to the consideration of alternative spray methods for EMI shielding.
The authors will discuss the development of spray coating processes for applying EMI shielding materials to the external surfaces of individual components on strips and larger SiP packages. Using newly developed and improved materials and equipment for the industry, a process has been demonstrated that provides uniform coverage on packages less than 10 microns thick and uniform coverage around package corners and package sidewalls. side wall thickness ratio 1:1. Further research has shown that the manufacturing cost of applying EMI shielding to component packages can be reduced by increasing the spray rate and selectively applying coatings to specific areas of the package. In addition, the low capital cost of the equipment and the shorter set-up time for spraying equipment compared to spraying equipment improve the ability to increase production capacity.
When packaging mobile electronics, some manufacturers of SiP modules face the problem of isolating components inside the SiP from each other and from the outside to protect against electromagnetic interference. Grooves are cut around the internal components and conductive paste is applied to the grooves to create a smaller Faraday cage inside the case. As the trench design narrows, it is necessary to control the volume and accuracy of the placement of the material filling the trench. The latest advanced blasting products control volume and the narrow airflow width ensures accurate trench filling. In the last step, the tops of these paste-filled trenches are glued together by applying an external EMI shielding coating. Spray Coating solves the problems associated with the use of sputtering equipment and takes advantage of improved EMI materials and deposition equipment, allowing SiP packages to be manufactured using efficient internal packaging methods.
In recent years, EMI shielding has become a major concern. With the gradual mainstream adoption of 5G wireless technology and the future opportunities that 5G will bring to the Internet of Things (IoT) and mission-critical communications, the need to effectively protect electronic components and assemblies from electromagnetic interference has increased. essential. With the upcoming 5G wireless standard, signal frequencies in the 600 MHz to 6 GHz and millimeter wave bands will become more common and powerful as the technology is adopted. Some proposed use cases and implementations include window panes for office buildings or public transportation to help keep communication over shorter distances.
Because 5G frequencies have difficulty penetrating walls and other hard objects, other proposed implementations include repeaters in homes and office buildings to provide adequate coverage. All these actions will lead to an increase in the prevalence of signals in the 5G frequency bands and a higher risk of exposure to electromagnetic interference in these frequency bands and their harmonics.
Fortunately, EMI can be shielded by applying a thin, conductive metal coating to external components and System-in-Package (SiP) devices (Figure 1). In the past, EMI shielding has been applied by placing stamped metal cans around groups of components, or by applying shielding tape to individual components. However, as packages and end devices continue to be miniaturized, this shielding approach becomes unacceptable due to size limitations and the flexibility to handle the diverse, non-orthogonal package concepts that are increasingly being used in mobile and wearable electronics.
Likewise, some leading package designs are moving towards selectively covering only certain areas of the package for EMI shielding, rather than covering the entire exterior of the package with a full package. In addition to external EMI shielding, new SiP devices require additional built-in shielding built directly into the package to properly isolate the various components from each other in the same package.
The main method for creating EMI shielding on molded component packages or molded SiP devices is to spray multiple layers of metal onto the surface. By sputtering, very thin uniform coatings of pure metal or metal alloys can be deposited on package surfaces with a thickness of 1 to 7 µm. Because the sputtering process is capable of depositing metals at the angstrom level, the electrical properties of its coatings have so far been effective for typical shielding applications.
However, as the need for protection grows, sputtering has significant inherent disadvantages that prevent it from being used as a scalable method for manufacturers and developers. The initial capital cost of spray equipment is very high, in the millions of dollars range. Due to the multi-chamber process, the spray equipment line requires a large area and further increases the need for additional real estate with a fully integrated transfer system. Typical sputter chamber conditions can reach the 400°C range as the plasma excitation sputters the material from the sputter target to the substrate; therefore, a “cold plate” mounting fixture is required to cool the substrate to reduce the temperatures experienced. During the deposition process, the metal is deposited on a given substrate, but, as a rule, the coating thickness of the vertical side walls of a 3D package is usually up to 60% compared to the thickness of the upper surface layer.
Finally, due to the fact that sputtering is a line-of-sight deposition process, metal particles cannot be selectively or must be deposited under overhanging structures and topologies, which can lead to significant material loss in addition to its accumulation inside the chamber walls; thus, it requires a lot of maintenance. If certain areas of a given substrate are to be left exposed or EMI shielding is not required, the substrate must also be pre-masked.
Protecting electronic systems from electromagnetic interference (EMI) has become a hot topic. Technological advances in 5G standards, wireless charging for mobile electronics, antenna integration into the chassis, and the introduction of System in Package (SiP) are driving the need for better EMI shielding and isolation in component packages and larger modular applications. For conformal shielding, EMI shielding materials for the outer surfaces of the package are mainly deposited using physical vapor deposition (PVD) processes using prepackaging technology for internal packaging applications. However, the scalability and cost issues of spray technology, as well as advances in consumables, are leading to the consideration of alternative spray methods for EMI shielding.
The authors will discuss the development of spray coating processes for applying EMI shielding materials to the external surfaces of individual components on strips and larger SiP packages. Using newly developed and improved materials and equipment for the industry, a process has been demonstrated that provides uniform coverage on packages less than 10 microns thick and uniform coverage around package corners and package sidewalls. side wall thickness ratio 1:1. Further research has shown that the manufacturing cost of applying EMI shielding to component packages can be reduced by increasing the spray rate and selectively applying coatings to specific areas of the package. In addition, the low capital cost of the equipment and the shorter set-up time for spraying equipment compared to spraying equipment improve the ability to increase production capacity.
When packaging mobile electronics, some manufacturers of SiP modules face the problem of isolating components inside the SiP from each other and from the outside to protect against electromagnetic interference. Grooves are cut around the internal components and conductive paste is applied to the grooves to create a smaller Faraday cage inside the case. As the trench design narrows, it is necessary to control the volume and accuracy of the placement of the material filling the trench. The latest advanced blasting products control volume and narrow airflow width ensures accurate trench filling. In the last step, the tops of these paste-filled trenches are glued together by applying an external EMI shielding coating. Spray Coating solves the problems associated with the use of sputtering equipment and takes advantage of improved EMI materials and deposition equipment, allowing SiP packages to be manufactured using efficient internal packaging methods.
In recent years, EMI shielding has become a major concern. With the gradual mainstream adoption of 5G wireless technology and the future opportunities that 5G will bring to the Internet of Things (IoT) and mission-critical communications, the need to effectively protect electronic components and assemblies from electromagnetic interference has increased. essential. With the upcoming 5G wireless standard, signal frequencies in the 600 MHz to 6 GHz and millimeter wave bands will become more common and powerful as the technology is adopted. Some proposed use cases and implementations include window panes for office buildings or public transportation to help keep communication over shorter distances.
Because 5G frequencies have difficulty penetrating walls and other hard objects, other proposed implementations include repeaters in homes and office buildings to provide adequate coverage. All these actions will lead to an increase in the prevalence of signals in the 5G frequency bands and a higher risk of exposure to electromagnetic interference in these frequency bands and their harmonics.
Fortunately, EMI can be shielded by applying a thin, conductive metal coating to external components and System-in-Package (SiP) devices (Figure 1). In the past, EMI shielding has been applied by placing stamped metal cans around groups of components, or by applying shielding tape to certain components. However, as packages and end devices continue to be miniaturized, this shielding approach becomes unacceptable due to size limitations and the flexibility to handle the variety of non-orthogonal package concepts that are increasingly found in mobile and wearable electronics.
Likewise, some leading package designs are moving towards selectively covering only certain areas of the package for EMI shielding, rather than covering the entire exterior of the package with a full package. In addition to external EMI shielding, new SiP devices require additional built-in shielding built directly into the package to properly isolate the various components from each other in the same package.
The main method for creating EMI shielding on molded component packages or molded SiP devices is to spray multiple layers of metal onto the surface. By sputtering, very thin uniform coatings of pure metal or metal alloys can be deposited on package surfaces with a thickness of 1 to 7 µm. Because the sputtering process is capable of depositing metals at the angstrom level, the electrical properties of its coatings have so far been effective for typical shielding applications.
However, as the need for protection grows, sputtering has significant inherent disadvantages that prevent it from being used as a scalable method for manufacturers and developers. The initial capital cost of spray equipment is very high, in the millions of dollars range. Due to the multi-chamber process, the spray equipment line requires a large area and further increases the need for additional real estate with a fully integrated transfer system. Typical sputter chamber conditions can reach the 400°C range as the plasma excitation sputters the material from the sputter target to the substrate; therefore, a “cold plate” mounting fixture is required to cool the substrate to reduce the temperatures experienced. During the deposition process, the metal is deposited on a given substrate, but, as a rule, the coating thickness of the vertical side walls of a 3D package is usually up to 60% compared to the thickness of the upper surface layer.
Finally, due to the fact that sputtering is a line-of-sight deposition process, metal particles cannot be selectively or must be deposited under overhanging structures and topologies, which can result in significant material loss in addition to its accumulation inside the chamber walls; thus, it requires a lot of maintenance. If certain areas of a given substrate are to be left exposed or EMI shielding is not required, the substrate must also be pre-masked.
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Post time: Apr-19-2023