Patent Description:
With development of technologies and increase of interfaces on a packaged chip, power consumption and a chip size are larger, and a higher requirement is posed on heat dissipation performance. Because a lid of a lidded packaged chip obstructs heat dissipation of the chip, a heat dissipation effect of the lidded packaged chip is poor. Therefore, a packaged chip structure also develops from a lidded packaged chip to a lidless packaged chip. When the packaged chip is used, the packaged chip needs to be connected to a circuit board to form a chip module. In the conventional technology, a solder ball is used to implement the connection between the packaged chip and the circuit board. In this connection mode, because materials of various parts of the packaged chip are different and expansion coefficients are different, a warp is prone to occur during soldering, and there is a potential risk of solder ball cracking. Therefore, reliability of the connection between the packaged chip and the circuit board is low. Therefore, the connection between the packaged chip and the circuit board can be implemented by using a slot. An elastic terminal is provided in the slot, and the packaged chip is pressed into the slot, so that a connecting part of the packaged chip is in reliable contact with the elastic terminal in the slot to connect the packaged chip to the circuit board. In the conventional technology, a heat radiator is press-fitted on the lid of the lidded packaged chip, and the lidded packaged chip can be reliably connected to the circuit board by using the lid. For the lidless packaged chip, because the lidless packaged chip does not have a lid, and surface flatness of one side of the lidless packaged chip facing away from the circuit board is poor, pressure of the heat radiator cannot be evenly distributed. On one hand, the heat radiator is prone to be skewed, and a die cannot be attached, resulting in a poor heat dissipation effect of the lidless packaged chip. On the other hand, when the heat radiator is skewed, the die may be crushed, causing damage to the lidless packaged chip. The document <CIT> Alshows a chip module with a circuit board, a slot and a lidless packaged chip with a radiator. The document <CIT> shows a low profile computer processor retention device. The document <CIT> shows a method and structure to provide balanced mechanical loading of devices in compressively loaded environments. The document <CIT> shows a package structure printed circuit board mounted with the same and an electronic apparatus having the printed circuit board. The document <CIT> shows an electronic device and a production method thereof. Especially, mounting chips on substrates is shown. The document <CIT> shows a removable package lower side device attachment. Especially, the device serves the purpose of attaching a chip to a substrate.

This application provides a chip module and an electronic device, to reliably connect a lidless packaged chip to a circuit board by using a slot and improve a heat dissipation effect of a heat radiator.

According to a first aspect, this application provides a chip module. The chip module includes a circuit board, a slot disposed on a surface of one side of the circuit board, a lidless packaged chip, a heat radiator, and a substrate fixing assembly. The lidless packaged chip includes a substrate and a die packaged on the substrate. The slot is electrically connected to the circuit board, the lidless packaged chip has a connecting part on one side of the substrate facing away from the die, and the connecting part is inserted into the slot, so that the connecting part is connected to an elastic terminal in the slot. The heat radiator is press-fitted on one side of the die facing away from the circuit board, to press a middle part of the lidless packaged chip toward the slot, so that the connecting part at the middle part of the lidless packaged chip is reliably connected to the elastic terminal in the slot. The substrate fixing assembly is press-fitted at a periphery of one side of the substrate facing away from the circuit board and avoids the die, to press an edge of the lidless packaged chip toward the slot, so that the connecting part at the edge of the lidless packaged chip is reliably connected to the elastic terminal in the slot. In this solution, a middle area of the lidless packaged chip having the die is pressed toward the slot by using the heat radiator, and an edge area of the substrate of the lidless packaged chip is pressed toward the slot by using the substrate fixing assembly, so that reliability of the connection between the lidless packaged chip and the slot is high. The chip module may use the slot to implement the connection between the lidless packaged chip and the circuit board, and the connection reliability is high. In addition, a heat dissipation effect of the lidless packaged chip is good, and the chip module has a good heat dissipation effect and good performance.

To improve strength of the lidless packaged chip, a reinforcing rib is further disposed on the substrate. The reinforcing rib and the die are disposed on a same side of the substrate, and the reinforcing rib is
disposed around the die. Therefore, strength of the substrate is high. The substrate fixing assembly can be in contact with one side of the reinforcing rib facing away from the substrate. The solution can enhance the strength of the lidless packaged chip.

When the heat radiator and the substrate fixing assembly are specifically mounted, pressure F1 between the heat radiator and the die and pressure F2 between the substrate fixing assembly and the substrate may satisfy: F <NUM> > F2. Usually, the lidless packaged chip has a crying warp, that is, a die area of the lidless packaged chip is bent in a direction away from the circuit board. In the technical solution of this application, the pressure F1 applied to the die area is set to be greater than the pressure F2 applied to the edge area. Therefore, a part of force in F1 can be used to correct the crying warp of the lidless packaged chip, and this further makes the lidless packaged chip reliably connected to the slot.

A specific structure of the substrate fixing assembly is not limited. In a specific implementation, the substrate fixing assembly may be an upper cover, and the upper cover has a hollow structure, so that the die is in contact with the heat radiator. In this solution, the upper cover may be used as a cover, or may be press-fitted on the substrate as a substrate fixing assembly.

When the upper cover is specifically disposed, the upper cover may be an integral structure, or may be formed by splicing sub-cover parts.

To mount the chip module, a lower cover is further included. The lower cover is disposed on one side of the circuit board facing away from the substrate. To facilitate mounting, a pre-tightening assembly is disposed between the upper cover and the lower cover, and the pre-tightening assembly makes the upper cover and the lower cover close to each other, to adjust pressure of the lower cover on the substrate when the lower cover is specifically mounted, so that skewing is unlikely to occur. In particular, for a chip module with a larger size, an anti-tilt effect is better.

The pre-tightening assembly has a plurality of optional structures. In a technical solution, the pre-tightening assembly includes a pre-tightening screw and a spring sleeved outside the pre-tightening screw. Therefore, when the spring is in an energy storage state, the lower cover and the upper cover can be close to each other.

When the upper cover is press-fitted on the substrate, the upper cover and the lower cover may be connected by using a first fastening screw. To control the pressure F2 applied by the upper cover to the substrate to satisfy a requirement, a spring is sleeved outside the first fastening screw. The spring is in an energy storage state and is used to provide pressure for pressing the upper cover toward the substrate, so that the upper cover is pressed toward the substrate with specified pressure and that a connecting part of the substrate is reliably connected to the elastic terminal in the slot.

Alternatively, in another technical solution, the upper cover may have an elastic metal, and the elastic metal is press-fitted on the substrate. In this solution, no spring needs to be sleeved outside the first fastening screw, and mechanical properties of the elastic metal are better than those of a spring. When the elastic metal is compressed, overpressure is unlikely to occur, and reliability is high.

Alternatively, in another technical solution, the upper cover may include a bracket and a pressing metal, and the pressing metal is press-fitted on one side of the substrate facing away from the circuit board. The pressing metal and the bracket are connected by using a spring set. The spring set is in a compressed state and is configured to provide pressure for press-fitting the pressing metal on the substrate. In this solution, no spring needs to be sleeved outside the first fastening screw either. The spring set between the pressing metal and the bracket can enable the pressing metal to apply specified pressure to the substrate.

During mounting of the heat radiator, the heat radiator may be mounted on the upper cover and/or the lower cover by using a second fastening screw. To control the pressure F1 applied by the heat radiator to the die to satisfy a requirement, a spring is also sleeved outside the second fastening screw. The spring is in an energy storage state and is used to provide pressure for pressing the heat radiator toward the die, so that the heat radiator is pressed toward the die with specified pressure and that the lidless packaged chip is reliably connected to the slot.

Specifically, each spring may be a pre-tightening spring, that is, torque of the pre-tightening spring may be preset, and specified pressure may be formed through direct mounting. Alternatively, the spring may be a compression spring, and required pressure may also be obtained by adjusting torque of a torque screwdriver when the screw is mounted.

During mounting of the heat radiator, a latch may alternatively be used as a pre-mounting structure. Specifically, a plurality of latches may be fixed to the lower cover, an edge of the heat radiator has a protrusion, and the latches are clamped with the protruding edge of the heat radiator in a direction from the heat radiator to the lower cover, so that the heat radiator can be pre-mounted. The heat radiator is prevented from being skewed during subsequent mounting of the heat radiator, and further, damage caused to the die by pressing edges or sharp corners of the die by the heat radiator can be reduced.

The lower cover may be a pre-bent lower cover. The pre-bent lower cover is in a natural state, that is, when the pre-bent lower cover is not mounted, an edge of the pre-bent lower cover is bent along a direction away from the circuit board. In this solution, a bending direction of the pre-bent lower cover is opposite to a warping direction of the lidless packaged chip, to counteract the warp of the lidless packaged chip and prevent the chip module from warping.

Alternatively, the lower cover may be an I-shaped lower cover. After the chip module is mounted, the screw makes a peripheral side of the I-shaped lower cover close, so that a middle part of the lower cover is raised. This can counteract the warp of the lidless packaged chip and prevent the chip module from warping.

To improve the heat dissipation effect of the lidless packaged chip, a surface of the upper cover facing toward the heat radiator is provided with a heat conduction layer, and a surface of the upper cover facing away from the heat radiator is provided with a heat conduction layer, so that heat of the lidless packaged chip is transferred to the heat radiator.

In another technical solution, the substrate fixing assembly may include a plurality of elastic pressing blocks, the heat radiator may have an accommodating groove for mounting the elastic pressing blocks, and the elastic pressing blocks are disposed in the accommodating groove. The elastic pressing blocks are press-fitted on a peripheral side of the substrate to press the edge of the lidless packaged chip toward the slot, thereby improving reliability of the connection between the lidless packaged chip and the circuit board. The elastic pressing block may include a spring and a pressing block. The spring is disposed between the pressing block and a bottom wall of the accommodating groove and is in a compressed state, so that the pressing block is pressed toward the substrate.

According to a second aspect, this application further provides an electronic device. The electronic device includes the chip module in any one of the foregoing technical solutions. The chip module of the electronic device has a good heat dissipation effect, and the connection between the lidless packaged chip and the circuit board is reliable.

To make objectives, technical solutions, and advantages of this application clearer, the following further describes this application in detail with reference to accompanying drawings.

Terms used in the following embodiments are merely intended to describe particular embodiments, but are not intended to limit this application. The terms "one", "a" and "this" of singular forms used in this specification and the appended claims of this application are also intended to include expressions such as "one or more", unless otherwise specified in the context clearly.

Referring to "an embodiment" or "some embodiments" or the like described in this specification means that one or more embodiments of this application include a specific feature, structure, or characteristic described with reference to the embodiment. Therefore, statements such as "in an embodiment", "in some embodiments", "in some other embodiments", and "in other embodiments" that appear at different places in this specification do not necessarily mean referring to a same embodiment. Instead, the statements mean "one or more but not all of embodiments", unless otherwise specifically emphasized in another manner. The terms "include", "have", and their variants all mean "include but are not limited to", unless otherwise specifically emphasized in another manner.

With development of electronic technologies, performance of a die used as a core component of an electronic device has attracted attention of persons skilled in the art. In the conventional technology, a chip in an electronic device such as a mobile phone, a computer, a smart wearable device, or a smart home appliance has a die inside. To improve protection of a die and implement communication of the die, it is usually necessary to dispose the die in a lidded packaged chip and then mount the packaged chip on a circuit board to form a chip module. <FIG> is a schematic view of a structure of a chip module in the conventional technology. The chip module includes a lower cover <NUM>, a circuit board <NUM>, a lidded packaged chip <NUM>, and a heat radiator <NUM>. The lidded packaged chip <NUM> is mounted on one side of the circuit board <NUM> facing away from the lower cover <NUM>, and the heat radiator <NUM> is press-fitted on one side of the lidded packaged chip <NUM> facing away from the circuit board <NUM>. A slot <NUM> is disposed on a surface of one side of the circuit board <NUM>, and the slot <NUM> is connected to the lidded packaged chip <NUM>. An elastic terminal <NUM> is provided in the slot <NUM>. The heat radiator <NUM> applies pressure to the lidded packaged chip <NUM>, so that a connecting part (not shown in the figure) of the lidded packaged chip <NUM> is connected to the elastic terminal <NUM> in the slot <NUM> disposed on the circuit board <NUM>. In this solution, the heat radiator <NUM> applies pressure to a lid <NUM> of the lidded packaged chip <NUM>, and the pressure may be applied to an entire top surface of the lidded packaged chip <NUM> more evenly under action of the lid <NUM>, so that the connecting part of the lidded packaged chip <NUM> is reliably connected to the elastic terminal <NUM> in the slot <NUM> of the circuit board <NUM>. With emergence of a lidless packaged chip <NUM>, because the lidless packaged chip <NUM> does not have a lid <NUM>, and flatness of a surface (or referred to as a top surface) on one side of the lidless packaged chip <NUM> facing away from the circuit board <NUM> is poor, pressure of a heat radiator <NUM> cannot be evenly distributed. Therefore, a problem that a heat dissipation effect is poor or that a die <NUM> is damaged is caused. Therefore, this application provides a chip module and an electronic device, so that a lidless packaged chip <NUM> is reliably connected to a slot <NUM> of a circuit board <NUM>, thereby improving a service life of the lidless packaged chip <NUM>. The following describes the technical solutions of this application in detail with reference to the accompanying drawings and embodiments.

<FIG> is a schematic exploded view of a structure of a chip module according to an embodiment of this application. <FIG> is a schematic sectional view of a structure of the chip module according to an embodiment of this application. As shown in <FIG> and <FIG>, the chip module includes a circuit board <NUM>, a lidless packaged chip <NUM>, a heat radiator <NUM>, and a substrate fixing assembly <NUM>. The lidless packaged chip <NUM> includes a substrate <NUM> and a die <NUM>. The die <NUM> is packaged on the substrate <NUM>. The lidless packaged chip <NUM> is electrically connected to the circuit board <NUM>. Specifically, a slot <NUM> is disposed on the circuit board <NUM>, an elastic terminal <NUM> is provided in the slot <NUM>, one side of the substrate <NUM> facing away from the die <NUM> has a connecting part electrically connected to the die <NUM>, and the connecting part is connected to the elastic terminal <NUM> in the slot <NUM>. The connecting part may be a pin or may be a pad. This is not specifically limited in this application. To implement a reliable connection between the lidless packaged chip <NUM> and the slot <NUM> of the circuit board <NUM>, the heat radiator <NUM> is press-fitted on one side of the die <NUM> facing away from the circuit board <NUM>, so that pressure toward the circuit board <NUM> is applied to the die <NUM>. The substrate fixing assembly <NUM> is press-fitted at a periphery of one side of the substrate <NUM> facing away from the circuit board <NUM> and avoids the die <NUM>, so that pressure toward the circuit board <NUM> is applied to the periphery of the substrate <NUM>. In other words, the substrate fixing assembly <NUM> applies pressure to an edge of the lidless packaged chip <NUM>, so that there is even pressure between the lidless packaged chip <NUM> and the slot <NUM> of the circuit board <NUM> and that a connection between the edge of the lidless packaged chip <NUM> and the slot <NUM> of the circuit board <NUM> is reliable. In this solution, the chip module has the lidless packaged chip <NUM> with a good heat dissipation effect, and the lidless packaged chip <NUM> can be reliably connected to the circuit board <NUM>.

<FIG> is a schematic sectional view of another structure of the chip module according to an embodiment of this application. Referring to <FIG>, to improve structural strength of the lidless packaged chip <NUM> and reduce a warping degree, a reinforcing rib <NUM> (ring) is further disposed on the substrate <NUM>. The reinforcing rib <NUM> is located on one side of the substrate <NUM> facing toward the die <NUM>, that is, the reinforcing rib <NUM> and the die <NUM> are located on the same side of the substrate <NUM>, and the reinforcing rib <NUM> is disposed around the die <NUM>. The substrate fixing assembly <NUM> may be press-fitted on one side of the reinforcing rib <NUM> facing away from the circuit board <NUM>. This solution can not only improve strength of the substrate <NUM>, but also prevent the substrate fixing assembly <NUM> from being directly fixed to the substrate <NUM>, thereby reducing damage to the substrate <NUM>.

In a specific technical solution, a heat conduction layer may be disposed between the heat radiator <NUM> and the die <NUM> to improve heat conductivity between the die <NUM> and the heat radiator <NUM> and improve a heat dissipation effect of the lidless packaged chip <NUM>. Specifically, the heat conduction layer may be a phase-change material layer, a carbon fiber layer, a graphite layer, or the like. This is not specifically limited in this application.

<FIG> are schematic diagrams of layouts of the reinforcing rib <NUM> of the lidless packaged chip <NUM> according to an embodiment of this application. Refer to <FIG>. A specific structure of the reinforcing rib <NUM> is not limited. The reinforcing rib <NUM> is a ring. As shown in <FIG>, the reinforcing rib <NUM> is a circular ring reinforcing rib, and the circular ring reinforcing rib is disposed on an outer peripheral side of the die <NUM>. As shown in <FIG>, the reinforcing rib <NUM> is a square ring reinforcing rib, and the square ring reinforcing rib is disposed on the outer peripheral side of the die <NUM>. As shown in <FIG>, the reinforcing rib <NUM> may further include a plurality of reinforcing rib sub-parts distributed on the outer peripheral side of the die <NUM>.

Still referring to <FIG>, pressure between the heat radiator <NUM> and the die <NUM> is F1, pressure between the substrate fixing assembly <NUM> and the substrate <NUM> is F2, and F1 and F2 satisfy: F1 > F2. Usually, during manufacturing of the lidless packaged chip <NUM>, because the die <NUM> needs to be packaged on the substrate <NUM>, the lidless packaged chip <NUM> after the packaging has a crying warp, that is, the lidless packaged chip <NUM> has a protruding warp in a direction toward the die <NUM> and away from the substrate <NUM>. In the pressure F1 between the heat radiator <NUM> and the die <NUM>, a part of force is used to correct the warp, and another part of force presses an area of the lidless packaged chip <NUM> opposite to the die <NUM> toward the circuit board <NUM>, so that F1 is greater than F2. In this case, there may be even pressure between the lidless packaged chip <NUM> and the slot <NUM> of the circuit board <NUM>. Therefore, reliability of the connection between the lidless packaged chip <NUM> and the circuit board <NUM> is improved.

In a specific design of the chip module, when the pressure between the heat radiator <NUM> and the die <NUM> is F1 and the pressure between the substrate fixing assembly <NUM> and the substrate <NUM> is F2, it is possible to make F1:F2 greater than or equal to <NUM>:<NUM>. The inventors have performed a lot of experiments and simulations and confirmed that when F1 and F2 satisfy the foregoing ratio, there can be a good mounting effect and the pressure between the lidless packaged chip <NUM> and the circuit board <NUM> is even.

Referring to <FIG> and <FIG> is a schematic top view of the structure of the chip module after the heat radiator <NUM> is removed. When the substrate fixing assembly <NUM> is specifically disposed, the substrate fixing assembly <NUM> may be an upper cover <NUM>. The upper cover <NUM> has a hollow structure <NUM>, thereby avoiding the die <NUM> of the lidless packaged chip <NUM>. In addition, the upper cover <NUM> is in contact with the substrate <NUM> to apply pressure to the substrate <NUM>. The heat radiator <NUM> is in contact with the die <NUM> by using the hollow structure <NUM>, so that the heat radiator <NUM> can apply pressure to the die <NUM>. When the heat radiator <NUM> is specifically manufactured, the heat radiator <NUM> may have a protrusion in a direction toward the circuit board <NUM>, and the protrusion may pass through the hollow structure <NUM> and may be in contact with the die <NUM>. Pressure is separately applied to the die <NUM> and the substrate <NUM> of the lidless packaged chip <NUM>, and a tolerance between the die <NUM> and the substrate <NUM> can be absorbed. Therefore, reliability of the electrical connection between the lidless packaged chip <NUM> and the circuit board <NUM> is improved. Certainly, in a specific technical solution, the heat radiator <NUM> may be in contact with the die <NUM> through the hollow structure <NUM>. Alternatively, the die <NUM> may be in contact with the heat radiator <NUM> through the hollow structure <NUM>. Alternatively, a contact area between the heat radiator <NUM> and the die <NUM> is located in the hollow structure <NUM>.

When the upper cover <NUM> is specifically disposed, a specific structure of the upper cover <NUM> is not limited. For example, the upper cover <NUM> may be an integrally formed upper cover <NUM> with an integral structure. Alternatively, the upper cover <NUM> may include a plurality of sub-cover parts, and the upper cover <NUM> may be formed by splicing the plurality of sub-cover parts.

<FIG> is a schematic view of a structure of the chip module according to an embodiment of this application. To mount the chip module, a pre-tightening assembly <NUM> may be disposed between the upper cover <NUM> and the lower cover <NUM> of the chip module, and the pre-tightening assembly <NUM> can make the upper cover <NUM> have a trend of getting close to the lower cover <NUM>, to facilitate a subsequent mounting operation. Specifically, a value of pressure of the upper cover <NUM> toward the substrate <NUM> can be easily adjusted.

When the pre-tightening assembly <NUM> is specifically disposed, the pre-tightening assembly <NUM> may include a pre-tightening screw <NUM> and a spring <NUM> sleeved outside the pre-tightening screw <NUM>, and the pre-tightening screw <NUM> only pre-connects the upper cover <NUM> and the lower cover <NUM>. Specifically, a connecting part of the substrate <NUM> of the lidless packaged chip <NUM> may not be in contact with the elastic terminal <NUM> in the slot <NUM>, or may be in non-contact with the elastic terminal <NUM> in the slot <NUM>. In short, the connecting part is not completely fixed to the elastic terminal <NUM> in the slot <NUM>. Because the spring <NUM> is sleeved outside the pre-tightening screw <NUM>, connecting force F3 between the upper cover <NUM> and the lower cover <NUM> is controlled by controlling torque of the pre-tightening screw <NUM>. The connecting force F3, the pressure F1 between the heat radiator <NUM> and the die <NUM>, and the pressure F2 between the substrate fixing assembly <NUM> and the substrate <NUM> satisfy the following relationship: F3<F2<F1. This solution is advantageous for mounting of a chip module with a large size.

When the spring is specifically disposed, the spring may be a pre-tightening spring (torsion spring), that is, after torque is preset, the pre-tightening screw with the pre-tightening spring is mounted and connected to the upper cover and the lower cover. In this case, the required connecting force F3 may exist between the upper cover and the lower cover. The mounting process of this solution is simple. Alternatively, the spring may be a common compression spring, and the pre-tightening screw is mounted by using a torque screwdriver when the pre-tightening screw is mounted. When the torque of the torque screwdriver satisfies a requirement, the required connecting force F3 exists between the upper cover and the lower cover. In this solution, costs of the spring are low. Alternatively, when the spring is a common compression spring, the connecting force F3 may be controlled by controlling a compression stroke of the spring, but precision of this solution is low.

In another specific embodiment, the pre-tightening assembly <NUM> may further include a structure such as an elastic metal or an elastic hook. Details are not described in this application.

<FIG> is a schematic partial view of a structure of the slot <NUM> according to an embodiment of this application. The slot <NUM> includes the elastic terminal <NUM> and a limiting block <NUM>. With reference to <FIG>, the limiting block <NUM> limits the lidless packaged chip <NUM> in a direction toward the lidless packaged chip <NUM>. By properly setting a size relationship between the limiting block <NUM> and the elastic terminal <NUM>, when the substrate <NUM> of the lidless packaged chip <NUM> is in contact with the limiting block <NUM>, the connecting part of the substrate <NUM> is reliably connected to the elastic terminal <NUM>, and elasticity of the elastic terminal <NUM> is not damaged. Therefore, reliability of the electrical connection and a service life of the chip module are improved.

Still referring to <FIG>, the upper cover <NUM> and the lower cover <NUM> may be connected by using a first fastening screw <NUM>, so that the upper cover <NUM> applies the specified pressure F2 to the substrate <NUM>. A spring <NUM> is sleeved outside the first fastening screw <NUM>, and the spring <NUM> is in a compressed state. The spring may provide pressure for pressing the upper cover <NUM> toward the substrate <NUM>, so that the substrate <NUM> can be pressed toward the circuit board <NUM>. Specifically, when the first fastening screw <NUM> is mounted, a value of the pressure F2 applied by the upper cover <NUM> to the substrate <NUM> may be determined based on torque of the first fastening screw <NUM>. In other words, the torque that needs to be applied to the first fastening screw <NUM> may be determined based on the required pressure F2 applied to the substrate <NUM> by the upper cover <NUM>, to satisfy a product requirement. After the first fastening screw <NUM> is mounted, the lidless packaged chip <NUM> is in contact with the limiting block <NUM> of the circuit board <NUM>, and the connecting part is reliably connected to the elastic terminal <NUM>.

When the heat radiator <NUM> is mounted, the heat radiator <NUM> may be connected to the upper cover <NUM>, or the heat radiator <NUM> may be connected to the lower cover <NUM>. This is not limited in this application. However, when the heat radiator <NUM> is specifically mounted, the heat radiator <NUM> may be connected to the upper cover <NUM> or the lower cover <NUM> by using a second fastening screw <NUM>. A spring <NUM> is also sleeved outside the second fastening screw <NUM>, and the spring is in a compressed state. The spring may provide pressure for pressing the heat radiator <NUM> toward the die <NUM>, so that the die <NUM> is pressed toward the circuit board. Specifically, when the second fastening screw is mounted, a value of the pressure F1 applied by the heat radiator <NUM> to the die <NUM> may be determined by adjusting torque of the second fastening screw <NUM>. In other words, the torque that needs to be applied to the second fastening screw <NUM> may be determined based on the required pressure F1 applied to the die <NUM> by the heat radiator <NUM>.

When the spring outside the first fastening screw and the spring outside the second fastening screw are specifically disposed, the springs may be pre-tightening springs (torsion springs), that is, after torque is preset and the screws with the pre-tightening springs are mounted, the specified pressure may be formed. The mounting process of this solution is simple. Alternatively, the spring may be a common compression spring, and the screw is mounted by using a torque screwdriver when the screw is mounted, and the mounting is completed when the torque of the torque screwdriver satisfies a requirement. In this solution, costs of the spring are low. Alternatively, when the spring is a common compression spring, the pressure may be controlled by controlling a compression stroke of the spring, but precision of this solution is low.

<FIG> is a partial sectional view of the chip module according to an embodiment of this application. A plurality of latches <NUM> are further fixed to the lower cover <NUM>, and the latches <NUM> are clamped with the protrusion of the edge of the heat radiator <NUM>, so that the heat radiator <NUM> can be pre-mounted. Specifically, the plurality of latches <NUM> may be evenly distributed on a peripheral side of the lower cover <NUM>, so that the heat radiator <NUM> and the lower cover <NUM> keep stable and are not prone to tilt. In this way, the die <NUM> is prevented from being damaged by impact of concentrated stress of the heat radiator <NUM>, and the service life of the chip module is improved. In particular, the heat radiator <NUM> may be mounted after the upper cover <NUM> and the lower cover <NUM> are pre-mounted. In this case, the heat radiator <NUM> is prefixed with the lower cover <NUM> by using the latches <NUM>, so that when the second fastening screw <NUM> is mounted in a direction, the heat radiator <NUM> is unlikely to be skewed due to absence of a fixing structure in a direction opposite to the direction when the heat radiator <NUM> is subsequently mounted. This solution is advantageous for mounting of a chip module with a large size.

<FIG> is a schematic sectional view of another structure of the chip module according to an embodiment of this application. With reference to <FIG>, referring to <FIG>, the lower cover <NUM> is a pre-bent lower cover <NUM>. When the pre-bent lower cover is in a natural state, an edge of the pre-bent lower cover <NUM> is bent in a direction away from the circuit board <NUM>. In other words, when not mounted, the lower cover <NUM> is in a bent shape, as shown in <FIG>. In this solution, after the lidless packaged chip <NUM> is mounted on the circuit board <NUM>, an area in which the die <NUM> is located tends to deform toward the circuit board <NUM>. After the mounting is completed, the pre-bent lower cover <NUM> may counteract the foregoing deformation trend of the lidless packaged chip <NUM>, so that the chip module remains in a flat state, as shown in <FIG>. This helps improve reliability of the connection between the lidless packaged chip <NUM> and the slot <NUM> of the circuit board <NUM>.

<FIG> is a schematic sectional view of another structure of the chip module according to an embodiment of this application. Specifically, <FIG> shows a structure in a state in which the lower cover is not mounted. The lower cover <NUM> may be an I-shaped lower cover. To be specific, the I-shaped lower cover includes an upper plate, a lower plate, and a sandwiching block. The sandwiching block is located between the upper plate and the lower plate, and may be specifically located in a middle area between the upper plate and the lower plate. In this solution, after the lidless packaged chip <NUM> is mounted on the circuit board <NUM>, the area in which the die <NUM> is located tends to deform toward the circuit board <NUM>. <FIG> is a schematic sectional view of another structure of the chip module according to an embodiment of this application. Specifically, <FIG> shows a structure in a state in which the lower cover is mounted. After the lower cover <NUM> is mounted, a peripheral side of the I-shaped lower cover is tightened by using a screw, so that edge areas of the upper plate and the lower plate are close to each other. In this case, an area in which the sandwiching block is raised, and this may counteract the foregoing deformation trend of the lidless packaged chip <NUM>, so that the chip module remains in a flat state, as shown in <FIG>. This helps improve reliability of the connection between the lidless packaged chip <NUM> and the slot <NUM> of the circuit board <NUM>.

<FIG> is a schematic view of a structure of the upper cover according to an embodiment of this application. With reference to <FIG>, a plurality of elastic metals <NUM> may be further disposed on the upper cover <NUM>, and the elastic metals <NUM> of the upper cover <NUM> are press-fitted on the substrate <NUM>. The elastic metals <NUM> may provide pressure for pressing the substrate <NUM> toward the circuit board <NUM>. In this solution, elastic force of the elastic metals <NUM> can be used to adjust the pressure F2 between the upper cover <NUM> and the substrate <NUM>. In this solution, pressure of the upper cover <NUM> on the lidless packaged chip <NUM> may be precisely controlled by adjusting specific positions and elastic performance of the elastic metals <NUM>. <FIG> is a curve chart of mechanical properties of an elastic metal and a spring. There is a linear growth relationship between elastic force of the spring and an amount of deformation of the spring. If the amount of deformation of the spring is larger, the elastic force of the spring is stronger. A relationship between elastic force of the elastic metal and an amount of deformation of the elastic metal is first an approximately linear growth relationship. When the amount of deformation of the elastic metal reaches a value, the elastic force of the elastic metal tends to become stable and will not increase greatly. In the technical solution of this application, compared with the spring sleeved outside the first fastening screw <NUM>, the elastic metal <NUM> has a reliable structure and higher adaptability, and overpressure of the upper cover <NUM> on the substrate <NUM> is unlikely to occur.

<FIG> is a schematic view of another structure of the upper cover <NUM> according to an embodiment of this application. In another technical solution, the upper cover <NUM> may further include a bracket <NUM> and a pressing metal <NUM>, and the bracket <NUM> is fixedly connected to the lower cover <NUM>. A spring set <NUM> is connected between the pressing metal <NUM> and the bracket <NUM>, and the pressing metal <NUM> is press-fitted on the substrate <NUM> under action of pressure of the spring set <NUM>. The pressure F2 between the upper cover <NUM> and the substrate <NUM> is adjusted by adjusting elastic force of the spring set <NUM>.

<FIG> is a schematic sectional view of another structure of the chip module according to an embodiment of this application. To improve a heat dissipation capability of the chip module, a heat conduction layer <NUM> is provided on both a surface of the upper cover <NUM> facing toward the heat radiator <NUM> and a surface of the upper cover <NUM> facing away from the heat radiator <NUM>. Therefore, heat of the substrate <NUM> of the lidless packaged chip <NUM> can be transferred to the heat radiator through the heat conduction layer <NUM> and the upper cover <NUM>, so that the heat dissipation effect of the lidless packaged chip <NUM> is improved.

Further, a heat conduction layer <NUM> may also be disposed between the circuit board <NUM> and the lower cover <NUM>, so that the chip module can also perform heat dissipation in a direction of the lower cover <NUM>. In this case, an overall heat dissipation capability of the chip module is high, and this helps improve work efficiency of the chip module.

The heat conduction layer <NUM> may be specifically a metal layer or a graphite layer. This is not limited in this application. The heat conduction layer <NUM> may be an integral structure, or may include a plurality of sub-parts that form the heat conduction layer <NUM> as a whole.

Claim 1:
A chip module, comprising a circuit board (<NUM>), a slot (<NUM>) disposed on a surface of the circuit board (<NUM>), a lidless packaged chip (<NUM>), a heat radiator (<NUM>), and a substrate fixing assembly (<NUM>), wherein
the lidless packaged chip (<NUM>) comprises a substrate (<NUM>) and a die (<NUM>) packaged on the substrate (<NUM>), a connecting part of the lidless packaged chip (<NUM>) is connected to an elastic terminal in the slot (<NUM>), the heat radiator (<NUM>) is press-fitted on one side of the die (<NUM>) facing away from the circuit board (<NUM>), and the substrate fixing assembly (<NUM>) is press-fitted at a periphery of one side of the substrate (<NUM>) away from the circuit board (<NUM>) and avoids the die (<NUM>),
wherein the lidless packaged chip (<NUM>) comprises a reinforcing rib (<NUM>) disposed on the substrate (<NUM>); the reinforcing rib (<NUM>) and the die (<NUM>) are located on a same side of the substrate (<NUM>), and the reinforcing rib (<NUM>) is disposed around the die (<NUM>); and the substrate fixing assembly (<NUM>) is in contact with one side of the reinforcing rib (<NUM>) facing away from the substrate (<NUM>).