Patent Description:
High power density and miniaturization are a technical development trend of a switching power module. <CIT> discloses a semiconductor device includes a semiconductor body having a first main surface. The semiconductor body includes an active device area and an edge termination area at least partly surrounding the active device area. The semiconductor device further includes a contact electrode on the first main surface and electrically connected to the active device area. The semiconductor device further includes a passivation structure on the edge termination area and laterally extending into the active device area. The semiconductor device further includes an encapsulation structure on the passivation structure and covering a first edge of the passivation structure above the contact electrode. The passivation structure may comprise undoped silicate glass and tetraethyl orthosilicate. <CIT> discloses a package includes a redistribution portion, a first portion, and a second portion. The first portion is coupled to the redistribution portion. The first portion includes a first switch comprising a plurality of switch interconnects, and a first encapsulation layer that at least partially encapsulates the first switch. The second portion is coupled to the first portion. The second portion includes a first plurality of filters. Each filter includes a plurality of filter interconnects. The second portion also includes a second encapsulation layer that at least partially encapsulates the first plurality of filters. The first portion includes a second switch positioned next to the first switch, where the first encapsulation layer at least partially encapsulates the second switch. The second portion includes a second plurality of filters positioned next to the first plurality of filters, where the second encapsulation layer at least partially encapsulates the second plurality of filters. With application of a 5th generation communications technology, power density of a circuit board increases, power consumption of the circuit board also increases, and a daily temperature difference of the circuit board accordingly increases. Therefore, a demand for a switching power module with high power density and a long temperature cycle life is to greatly increase in the future. To ensure reliability of the switching power module during use, a passivation layer is disposed on a die of the circuit board to protect a circuit on the die. However, if a temperature change rate of a cyclic temperature around the switching power module is relatively large, for example, the temperature change rate is between minus <NUM> degrees Celsius and <NUM> degrees Celsius, the passivation layer in the conventional technology is prone to be cracked because of being in the temperature difference change for long time, causing a failure of the switching power module. Therefore, a requirement of the switching power supply module for long-time reliable operation under this temperature cycle condition cannot be met.

This application provides a switching power module and a communications device, to improve reliability of the switching power module and this claimed invention is described in the independent product claim <NUM>.

According to a first aspect, a switching power module is provided. The switching power module may be applied to the field of switching power modules. The switching power module includes a substrate, a die, and a packaging layer, wherein the die is embedded in the substrate, and the die has an integrated circuit layout layer; wherein the packaging layer is configured to package the integrated circuit layout layer of the die, the packaging layer comprising a composite material layer comprising at least a first material layer and a second material layer that have different functions, wherein the first material layer is formed, through high-density plasma deposition, on a surface of the die that faces away from the substrate (<NUM>) and covers the integrated circuit layout layer. The first material layer is a mixed layer of undoped silicate glass and tetraethyl orthosilicate, and the first material layer is filled in a gap between metal protrusions of the integrated circuit layout layer, thereby improving an isolation effect between the metal protrusions. A a mixing ratio of the mixed layer of the undoped silicate glass and the tetraethyl orthosilicate is greater than or equal to <NUM>:<NUM> and less than or equal to <NUM>:<NUM>. The mixed layer of the undoped silicate glass and the tetraethyl orthosilicate has a good thermal stress effect. Therefore, when a relatively large temperature difference cycle change occurs during working of the die, the first material layer does not crack, thereby improving a protection effect for the die and also improving reliability of the die.

The first material layer that uses the claimed ratio has a good thermal stress effect.

In a specific implementable solution, a thickness of the first material layer is greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>). When the thickness is used, it is ensured that the first material layer has a good thermal stress effect.

In a specific implementable solution, a thickness of the first material layer is greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>). This ensures that the first material layer has a good thermal stress effect.

In a specific implementable solution, a total thickness of the passivation layer is greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>). This improves a protection effect of the passivation layer for the die.

According to a second aspect, a communication device is provided. The communications device includes the switching power module according to any one of the first aspect and the specific implementable solutions of the first aspect, and a control component connected to the switching power module, wherein the control component is configured to control the switching power module. Therefore, when a relatively large temperature difference cycle change occurs during working of a die, a first material layer does not crack, thereby improving a protection effect for the die and also improving reliability of the die.

For ease of understanding, an application scenario of a switching power module provided in embodiments of this application is first described. The switching power module provided in embodiments of this application is applied to a communications device, and is configured to control working status switching of the communications device. In the conventional technology, high power density and miniaturization are a technical development trend of a switching power module.

With application of a 5th generation communications technology, power density of a circuit board further increases, and consequently power consumption of the circuit board accordingly increases. When the circuit board is used, a daily temperature difference of the circuit board also accordingly increases. Therefore, a demand for a switching power module with high power density and a long temperature cycle life is to greatly increase.

For high power density and miniaturization of the circuit board, currently there is a packaging manner applicable to a circuit board with high power density. A packaged die shown in <FIG> includes a substrate <NUM>, and the substrate <NUM> may be an organic substrate. A bare die <NUM> and a passivation layer (not shown in the figure) that packages the bare die <NUM> are embedded in the substrate <NUM>. The passivation layer is configured to implement electrical isolation between internal components of the die <NUM> and also protect interconnection between the internal components, and further can protect the components in the die <NUM> from being mechanically and chemically damaged. A material and a structure of the passivation layer greatly affect a stress release rate of the packaged die. The packaged die is disposed on a circuit board <NUM>. The die <NUM> is electrically connected (not shown in the figure) to the circuit board <NUM> to form a switching power module. When the switching power module is used and a temperature difference of the circuit board is relatively large, whether the passivation layer can well release a thermal stress directly affects reliability of the packaged die.

For example, a temperature cycle reliability test may be used to verify a temperature cycle life of the switching power module. A verification condition is usually as follows: A temperature circulates between minus <NUM> degrees Celsius and <NUM> degrees Celsius, a temperature change rate is greater than or equal to <NUM> degrees Celsius per minute, and a stage of minus <NUM> degrees Celsius and a stage of <NUM> degrees Celsius each need to be maintained for at least <NUM> minutes. In addition, when the switching power module is in a rating working area after being powered on, a power failure cannot occur during <NUM> cycles. In this way, a temperature cycle tolerance of the passivation layer of the die is checked, and a determining basis is whether the passivation layer of the die is cracked. When a switching power module in the conventional technology is verified, under repeated actions of a thermal stress, a passivation layer is separated from a neighboring insulation layer on the die, and a metal layer of the die migrates under excitation of an electric potential difference, causing damage to the die. In view of this, embodiments of this application provide die packaging. The following describes the die packaging in detail with reference to specific accompanying drawings and embodiments.

<FIG> is a cutaway drawing of a switching power module according to an embodiment of this application. The switching power module provided in this embodiment of this application includes a substrate <NUM>, a die <NUM>, and a packaging layer <NUM>. The substrate <NUM> is configured to carry the die <NUM> and the packaging layer <NUM> as a carrying component. The packaging layer <NUM> is configured to protect security of the die <NUM> as a protection component of the die <NUM>. The following describes the switching power module with reference to accompanying drawings and specific embodiments.

The substrate <NUM> provided in this embodiment of this application may be a circuit board, and the substrate <NUM> has a circuit layer electrically connected to the die <NUM>. During assembly, the die <NUM> is embedded in the substrate <NUM>, and can be connected to the circuit layer of the substrate <NUM> to form a circuit, to complete a function of the die <NUM>.

The die <NUM> has an integrated circuit layout layer (not shown in the figure). The integrated circuit layout layer is disposed on a surface of the die <NUM>, and the integrated circuit layout layer is configured to be electrically connected to the circuit layer of the substrate <NUM>.

The packaging layer <NUM> is configured to package the integrated circuit layout layer of the die <NUM> to ensure security of the integrated circuit layout layer of the die <NUM>. During disposition, the packaging layer <NUM> includes a composite material layer covering the integrated circuit layout layer, and the composite material layer includes at least two material layers that have different functions. The following describes, in detail with reference to accompanying drawings, the at least two material layers of the composite material layer provided in this embodiment of this application.

<FIG> is a schematic diagram of cooperation between the die and the packaging layer. The die <NUM> provided in this embodiment of this application is a bare die, and the integrated circuit layout layer <NUM> of the die <NUM> is a circuit on the die <NUM>. It should be understood that there is a gap in the integrated circuit layout layer <NUM> of the die <NUM>. Two metal protrusions of the integrated circuit layout layer <NUM> shown in <FIG> are used as an example. The two metal protrusions are a first cable <NUM> and a second cable <NUM>. The first cable <NUM> and the second cable <NUM> each are a solid metal part of the integrated circuit layout layer <NUM>. A gap between the first cable <NUM> and the second cable <NUM> is the gap of the integrated circuit layout layer <NUM>.

The packaging layer <NUM> covers the integrated circuit layout layer <NUM> of the die <NUM> during packaging. The packaging layer <NUM> provided in this embodiment of this application uses a three-layer structure. A first material layer <NUM> covers the die <NUM>, a second material layer <NUM> covers the first material layer <NUM>, and a third material layer <NUM> covers the second material layer <NUM>. The die <NUM> is sequentially covered by the first material layer <NUM>, the second material layer <NUM>, and the third material layer <NUM>, to protect the die <NUM>.

When covering the die <NUM>, the first material layer <NUM> covers the integrated circuit layout layer <NUM> of the die <NUM>, and is filled in a gap between metal protrusions of the integrated circuit layout layer <NUM> to implement electrical isolation between internal components of the die <NUM>. The first cable <NUM> and the second cable <NUM> are used as an example. The first material layer <NUM> has a protrusion filled in the gap between the first cable <NUM> and the second cable <NUM>, and the protrusion physically isolates the first cable <NUM> and the second cable <NUM>. In addition, the first material layer <NUM> is prepared by using an insulating material. Therefore, the formed protrusion electrically isolates the first cable <NUM> and the second cable <NUM>.

To improve a protection effect of the packaging layer <NUM> for the die <NUM>, the first material layer <NUM> is formed as a mixed layer by using a mixture that is of undoped silicate glass (Undoped Silicate Glass) and tetraethyl orthosilicate and that is prepared by using a high-density plasma chemical vapor deposition method. During preparation, first, a first layer of structure is prepared on the integrated circuit layout layer <NUM> by using the undoped silicate glass, and then a second layer of structure is prepared on the first layer of structure by using the tetraethyl orthosilicate. According to the invention, a ratio of the undoped silicate glass to the tetraethyl orthosilicate is greater than or equal to <NUM>:<NUM> and less than or equal to <NUM>:<NUM>. The undoped silicate glass has good hole filling density and is relatively hard. The tetraethyl orthosilicate has good coverage and is relatively soft. When the undoped silicate glass is mixed with the tetraethyl orthosilicate, the undoped silicate glass can tolerate a relatively large pressure like concrete, and the tetraethyl orthosilicate can absorb a part of a stress like a sponge, so that the first material layer <NUM> has both good hardness and good flexibility. When a temperature difference sharply changes or a temperature difference period changes, the first material layer <NUM> can tolerate a temperature change between minus <NUM> degrees Celsius and <NUM> degrees Celsius, and can relatively rapidly absorb heat generated by the die <NUM>, to avoid deformation of the first material layer <NUM> due to the heat generated by the die <NUM>, thereby reducing a cracking risk of the first material layer <NUM>.

In an optional solution, a thickness of the first material layer <NUM> may be greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>), to ensure that the first material layer <NUM> has an enough thickness to improve a thermal stress effect of the packaging layer <NUM>. For example, the thickness of the first material layer <NUM> may be any thickness greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>), such as <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), or <NUM> angstroms (<NUM>).

When the first material layer <NUM> is specifically prepared, the first material layer <NUM> may be directly prepared on the die <NUM> in a chemical deposition manner. For example, the first material layer <NUM> is prepared on the die <NUM> through high-density plasma chemical vapor deposition. During specific preparation, first, the undoped silicate glass is mixed with the tetraethyl orthosilicate, and then the mixture is prepared on the die <NUM> through high-density plasma chemical vapor deposition. When the first material layer <NUM> is formed through deposition, the first material layer <NUM> covers the integrated circuit layout layer <NUM> of the die <NUM>.

The composite material layer further includes the second material layer <NUM>, and both a material and a function of the second material layer <NUM> are different from those of the first material layer <NUM>. During specific disposition, the second material layer <NUM> covers the first material layer <NUM>, and a material of the second material layer <NUM> may be silicon oxynitride or tetraethyl orthosilicate. During disposition, the second material layer <NUM> is stacked with the first material layer <NUM>, and is located on a surface that is of the first material layer <NUM> and that faces away from the die <NUM>. During preparation, the second material layer <NUM> may be formed on the first material layer <NUM> in a manner of chemical vapor deposition and coating and curing, so that the second material layer <NUM> can be securely connected to the first material layer <NUM>. Both the silicon oxynitride and the tetraethyl orthosilicate have advantages such as thermal shock resistance, oxidation resistance, high density, an excellent mechanical property, and an excellent chemical stability, and are excellent high-temperature structural materials. The second material layer <NUM> prepared by using the silicon oxynitride or the tetraethyl orthosilicate can absorb a stress and the heat generated by the die <NUM>, to effectively protect the first material layer <NUM>. In addition, the second material layer <NUM> has a good thermal shock resistance property, so that the packaging layer <NUM> can well protect the die <NUM> when the temperature difference of the die <NUM> sharply changes or the temperature difference period of the die <NUM> changes.

In an optional solution, a thickness of the second material layer <NUM> is greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>), to ensure that the second material layer <NUM> has an enough thickness to improve a thermal stress effect of the packaging layer <NUM>. For example, the thickness of the second material layer <NUM> may be any thickness greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>), such as <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), or <NUM> angstroms (<NUM>).

The composite material layer may further include the third material layer <NUM>. The third material layer <NUM> covers the second material layer <NUM>, and a material of the third material layer <NUM> may be ultraviolet silicon nitride (UVSIN). When the third material layer <NUM> is prepared, the third material layer <NUM> is stacked with the second material layer <NUM> during disposition, and is located on a surface that is of the second material layer <NUM> and that faces away from the first material layer <NUM>. During preparation, the third material layer <NUM> may be directly formed on the second material layer <NUM> in a sputtering manner, so that the third material layer <NUM> can be securely connected to the first material layer <NUM>. The third material layer has good thermal shock resistance and good chemical stability because of being made of the ultraviolet silicon nitride.

In an optional solution, a thickness of the third material layer <NUM> is greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>), to ensure that the third material layer <NUM> has an enough thickness to improve a thermal stress effect of the packaging layer <NUM>. For example, the thickness of the third material layer <NUM> may be any thickness greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>), such as <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), or <NUM> angstroms (<NUM>).

When the packaging layer <NUM> is formed by using the first material layer <NUM>, the second material layer <NUM>, and the third material layer <NUM>, a height of the packaging layer <NUM> can be controlled to be greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>). For example, an overall thickness of the packaging layer <NUM> may be different thicknesses, such as <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), and <NUM> angstroms (<NUM>).

It should be understood that the composite material layer included in the packaging layer provided in this embodiment of this application is not limited to the three-layer material layer shown in <FIG>, and may be alternatively a material layer of another layer quantity as required.

To facilitate understanding of an effect of the packaging layer <NUM> provided in this embodiment of this application, temperature cycle reliability tests are performed on the packaging layer <NUM> shown in <FIG> and a packaging layer in the conventional technology to perform comparison.

The packaging layer in the conventional technology uses four layers of materials. A material of a first layer covering a die is silicon dioxide or ethyl orthosilicate, and a thickness of the first layer is <NUM> angstroms (<NUM>) to <NUM> angstroms (<NUM>). A material of a second layer is silicon dioxide, and a thickness of the second layer is <NUM> angstroms (<NUM>) to <NUM> angstroms (<NUM>). A material of a third layer is tetraethyl orthosilicate, and a thickness of the third layer is <NUM> angstroms (<NUM>) to <NUM> angstroms (<NUM>). A material of a fourth layer is silicon nitride, and a thickness of the fourth layer is <NUM> angstroms (<NUM>) to <NUM> angstroms (<NUM>). When a temperature cycle reliability test is performed on the packaging layer, when a temperature difference is greater than or equal to <NUM> degrees Celsius, the packaging layer is cracked. Therefore, a requirement of a current switching power module cannot be met.

When a temperature cycle reliability test is performed on the packaging layer <NUM> provided in this embodiment of this application, when a temperature around the packaging layer <NUM> provided in this embodiment of this application circulates between minus <NUM> degrees Celsius and <NUM> degrees Celsius, a temperature change rate is greater than or equal to <NUM> degrees Celsius per minute, and a stage of minus <NUM> degrees Celsius and a stage of <NUM> degrees Celsius each need to be maintained for at least <NUM> minutes, the packaging layer <NUM> is still kept uncracked. In addition, when the switching power module is in a rating working area after being powered on, no power failure occurs in <NUM> cycles.

It can be learned from the comparison that, the packaging layer <NUM> provided in this embodiment of this application can have a good thermal stress effect through cooperation between the first material layer <NUM>, the second material layer <NUM>, and the third material layer <NUM>. Therefore, under the premise of ensuring reliably of the die <NUM> during working, a quantity of layers of the packaging layer <NUM> is reduced, and a thickness of the packaging layer <NUM> is also reduced, thereby facilitating miniaturization development of the switching power module.

To facilitate understanding of the switching power module provided in this embodiment of this application, the following describes, in detail with reference to specific accompanying drawings, a method for preparing the switching power module shown in <FIG>.

Step <NUM>: Cover an integrated circuit layout layer of a die with a first material layer.

As shown in <FIG>, a first material layer <NUM> is directly prepared, through high-density plasma chemical vapor deposition, on a surface that is of a die <NUM> and that has an integrated circuit layout layer <NUM>. When the first material layer <NUM> covers the die <NUM>, the first material layer <NUM> covers the integrated circuit layout layer <NUM> of the die <NUM>, and is filled in a gap between metal protrusions of the integrated circuit layout layer <NUM>, to electrically isolate the adjacent metal protrusions.

Two metal protrusions in <FIG> are used as an example. The two metal protrusions are a first cable <NUM> and a second cable <NUM>. The first material layer <NUM> isprepared on the die <NUM> through high-density plasma chemical vapor deposition. During specific preparation, first, a first layer of structure is prepared on the integrated circuit layout layer <NUM> by using undoped silicate glass, and then a second layer of structure is prepared on the first layer of structure by using tetraethyl orthosilicate. The first material layer <NUM> further has a protrusion filled in a gap between the first cable <NUM> and the second cable <NUM>, and the protrusion physically isolates the first cable <NUM> and the second cable <NUM>. In addition, the undoped silicate glass and the tetraethyl orthosilicate of the first material layer <NUM> are mixed as an insulating material, so that the formed protrusion can electrically isolate the first cable <NUM> and the second cable <NUM>.

To improve a protection effect of the packaging layer <NUM> for the die <NUM>, the first material layer <NUM> is formed as a mixed layer by using a mixture that is of the undoped silicate glass (Undoped Silicate Glass) and the tetraethyl orthosilicate and that is prepared by using a high-density plasma chemical vapor deposition method. According to the invention, a ratio of the undoped silicate glass to the tetraethyl orthosilicate is greater than or equal to <NUM>:<NUM> and less than or equal to <NUM>:<NUM>. The undoped silicate glass has good hole filling density and is relatively hard. The tetraethyl orthosilicate has good coverage and is relatively soft. When the undoped silicate glass is mixed with the tetraethyl orthosilicate, the undoped silicate glass can tolerate a relatively large pressure like concrete, and the tetraethyl orthosilicate can absorb a part of a stress like a sponge, so that the first material layer <NUM> has both good hardness and good flexibility. When a temperature difference sharply changes or a temperature difference period changes, the first material layer <NUM> can tolerate a temperature change between minus <NUM> degrees Celsius and <NUM> degrees Celsius, and can relatively rapidly absorb heat generated by the die <NUM>, to avoid deformation of the first material layer <NUM> due to the heat generated by the die <NUM>, thereby reducing a cracking risk of the first material layer <NUM>.

When the first material layer <NUM> is specifically disposed, a thickness of the first material layer <NUM> may be greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>), to ensure that the first material layer <NUM> has an enough thickness to improve a thermal stress effect of the packaging layer. For example, the thickness of the first material layer <NUM> may be any thickness greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>), such as <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), or <NUM> angstroms (<NUM>).

Step <NUM>: Form a second material layer on the first material layer.

As shown in <FIG>, for some reference signs in <FIG>, refer to the same reference signs in <FIG>. A surface of the first material layer <NUM> is covered with a second material layer <NUM>, and a material of the second material layer <NUM> may be silicon oxynitride or tetraethyl orthosilicate. During disposition, the second material layer <NUM> is stacked with the first material layer <NUM>, and is located on a surface that is of the first material layer <NUM> and that faces away from the die. During preparation, the second material layer <NUM> may be formed on the first material layer <NUM> in a manner of chemical vapor deposition and coating and curing, so that the second material layer <NUM> can be securely connected to the first material layer <NUM>.

Both the silicon oxynitride and the tetraethyl orthosilicate have advantages such as thermal shock resistance, oxidation resistance, high density, an excellent mechanical property, and an excellent chemical stability, and are excellent high-temperature structural materials. The second material layer <NUM> prepared by using the silicon oxynitride or the tetraethyl orthosilicate can absorb a stress and the heat generated by the die <NUM>, to effectively protect the first material layer <NUM>. In addition, the second material layer <NUM> has a good thermal shock resistance property, so that the packaging layer <NUM> can well protect the die <NUM> when the temperature difference of the die <NUM> sharply changes or the temperature difference period of the die <NUM> changes.

In an optional solution, a thickness of the second material layer <NUM> is greater than or equal to <NUM> angstroms (<NUM>), and less than or equal to <NUM> angstroms (<NUM>), to ensure that the second material layer <NUM> has an enough thickness to improve a thermal stress effect of the packaging layer. For example, the thickness of the second material layer <NUM> may be any thickness greater than or equal to <NUM> angstroms (<NUM>), and less than or equal to <NUM> angstroms (<NUM>), such as <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), or <NUM> angstroms (<NUM>).

Step <NUM>: Form a third material layer on the second material layer.

As shown in <FIG>, for some reference signs in <FIG>, refer to the same reference signs in <FIG>. The second material layer <NUM> is covered with a third material layer <NUM>, and a material of the third material layer <NUM> may be ultraviolet silicon nitride (UVSIN). When the third material layer <NUM> is prepared, the third material layer <NUM> covers a surface that is of the second material layer <NUM> and that faces away from the first material layer. The third material layer <NUM> may be directly formed on the second material layer <NUM> in a sputtering manner, so that the third material layer <NUM> can be securely connected to the first material layer. The third material layer has good thermal shock resistance and good chemical stability because of being made of the ultraviolet silicon nitride.

In an optional solution, a thickness of the third material layer <NUM> is greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>), to ensure that the third material layer <NUM> has an enough thickness to improve a thermal stress effect of the packaging layer. For example, the thickness of the third material layer <NUM> may be any thickness greater than or equal to <NUM> angstroms (<NUM>) and less than or equal to <NUM> angstroms (<NUM>), such as <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), <NUM> angstroms (<NUM>), or <NUM> angstroms (<NUM>).

Step <NUM>: Embed the die in a substrate.

As shown in <FIG>, for some reference signs in <FIG>, refer to the same reference signs in <FIG>. The die <NUM> with the packaging layer <NUM> is embedded in a substrate <NUM>. Specifically, the substrate <NUM> may be prepared in layers, and the die <NUM> and the packaging layer <NUM> are embedded in the substrate <NUM> during the preparation in layers. Alternatively, a hole may be disposed on the substrate <NUM> after the substrate <NUM> is prepared, and the die <NUM> and the packaging layer <NUM> are embedded in the hole.

In addition, when the die <NUM> is embedded in the substrate <NUM>, the integrated circuit layout layer <NUM> of the die <NUM> is connected to a circuit layer of the substrate <NUM>. Specifically, the circuit layer on a surface of the substrate <NUM> may be connected to the integrated circuit layout layer <NUM> of the die <NUM> by disposing a via. For example, a via <NUM> is disposed on the substrate <NUM>. The via <NUM> is electrically connected to the first cable <NUM> after passing through the packaging layer <NUM> (sequentially passing through the third material layer <NUM>, the second material layer <NUM>, and the first material layer <NUM>), so that the first cable <NUM> is electrically connected to the circuit layer (not shown in the figure) on the surface of the substrate <NUM>. It should be understood that in <FIG>, only one via <NUM> is used as an example. A quantity of vias <NUM> is not limited in this embodiment of this application, and different quantities of vias <NUM> may be set based on connection requirements of the die <NUM> and the substrate <NUM>. In addition, a specific preparation manner of the via may be an existing preparation manner, and details are not described herein.

In the switching power module prepared by using the preparation method, the packaging layer <NUM> can have a good thermal stress effect through cooperation between the first material layer <NUM>, the second material layer <NUM>, and the third material layer <NUM>. Therefore, under the premise of ensuring reliably of the die <NUM> during working, a quantity of layers of the packaging layer <NUM> is reduced, and a thickness of the packaging layer <NUM> is also reduced, thereby facilitating miniaturization development of the switching power module.

An embodiment of this application further provides a communications device. The communications device includes the switching power module <NUM> according to any one of the foregoing embodiments, and a control component <NUM> connected to the switching power module <NUM>. <FIG> is a block diagram of a communications device. The communications device includes a control component <NUM> and a switching power module <NUM>. The control component <NUM> may send an instruction to control the switching power module <NUM> to be turned on or turned off, to control a working status of the communications device. It should be understood that a principle and a structure for controlling the switching power module <NUM> by the control component <NUM> are an existing common control manner, and details are not described herein.

In the switching power module, a mixed layer being the first material layer <NUM> disclosed in the present claimed independent claim <NUM>, and formed by using undoped silicate glass and tetraethyl orthosilicate is filled in a gap between metal protrusions of an integrated circuit layout layer, thereby improving an isolation effect between the metal protrusions. In addition, the mixed layer of the undoped silicate glass and the tetraethyl orthosilicate has a good thermal stress effect. Therefore, when a relatively large temperature difference cycle change occurs during working of a die, a first material layer does not crack, thereby improving a protection effect for the die and also improving reliability of the die.

Claim 1:
A switching power module (<NUM>), comprising a substrate (<NUM>), a die (<NUM>), and a packaging layer (<NUM>), wherein the die (<NUM>) is embedded in the substrate (<NUM>), and the die (<NUM>) has an integrated circuit layout layer; wherein
the packaging layer (<NUM>) is configured to package the integrated circuit layout layer of the die (<NUM>), the packaging layer (<NUM>) comprising a composite material layer comprising at least a first material layer (<NUM>) and a second material layer (<NUM>) that have different functions, wherein the first material layer (<NUM>) is formed, through high-density plasma deposition, on a surface of the die that faces away from the substrate (<NUM>) and covers the integrated circuit layout layer, wherein the first material layer (<NUM>) is a mixed layer of undoped silicate glass and tetraethyl orthosilicate, and the first material layer (<NUM>) is filled in a gap between metal protrusions (<NUM>, <NUM>) of the integrated circuit layout layer; and
characterized in that
a mixing ratio of the mixed layer of the undoped silicate glass and the tetraethyl orthosilicate is greater than or equal to <NUM>:<NUM> and less than or equal to <NUM>:<NUM>.