Packaging shielding structure design method and semiconductor packaging shielding structure

Abstract

The invention discloses a packaging shielding structure design method and a semiconductor packaging shielding structure, and the design method comprises the steps: building a simulation model of a patch antenna, and simulating a field intensity radiation pattern of the simulation model to obtain a radiation frequency point of the patch antenna; the current distribution diagram of the inner surface of the metal cover at the radiation frequency point is observed, so that an auxiliary groove is formed to form a new patch antenna; establishing a new simulation model of the patch antenna and simulating a field intensity radiation pattern of the patch antenna to obtain a radiation frequency point of the new patch antenna; judging whether the radiation frequency point of the patch antenna is far away from the main frequency of the semiconductor component, if so, determining the position and size of the current auxiliary slot as the design result output, and if not, adjusting the position and size of the auxiliary slot, or adding a new auxiliary slot. And repeating the simulation steps until the radiation frequency point of the patch antenna is far away from the main frequency of the semiconductor assembly. The electromagnetic radiation of the semiconductor packaging shielding structure is reduced on the premise of low cost, and the EMC performance is optimized.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging, and more particularly to the design and packaging of semiconductor packaging shielding structures. Background Technology

[0002] In semiconductor packaging, many packages have a single metal lid as a physical protection for the die and a reinforcement component, while also aiding in chip / package heat dissipation. However, a cavity is formed between the lid and the surface metal of the substrate; furthermore, the lid and substrate are bonded together with non-conductive adhesive, meaning there is a gap between them. Therefore, the cavity between the lid and substrate exhibits a patch antenna effect, amplifying the radiation of electromagnetic waves in certain frequency bands. Considering the presence of signal, power, module operating frequencies, or their higher harmonics within the cavity, electromagnetic interference (EMI) can occur if these frequencies coincide with the radiation frequency band of this patch antenna.

[0003] In the post-Moore's Law era, the demand for chiplets and advanced packaging is increasing. 2.5D / 3D packaging technologies offer higher interconnect density, more complex interconnect structures, and faster die-to-die interconnects. However, they also generate larger radiation sources within the package, leading to greater EMC challenges. Traditional solutions to these EMC issues mainly include three approaches: 1) Modify the package and lid dimensions, i.e., modify the surface-mount antenna dimensions, so that the antenna's radiation frequency avoids the operating frequencies of internal signals, power supplies, and modules, as well as their high-order harmonics. Examples include high-order harmonics of the core clock (covering the ~5GHz to ~20GHz range), broadband noise from high-speed interfaces (e.g., the 0~16GHz band of PCIe 5.0), harmonics of the memory bus (DDR) (e.g., the 3200MHz fundamental frequency of DDR5, and lower-order harmonics: 6400MHz, 9600MHz), and power supply noise (continuous broadband noise from DC to several hundred MHz). However, this approach significantly increases packaging costs.

[0004] 2) By adjusting registers to change the operating frequency or higher harmonic frequency of internal signals, power supplies, and modules (e.g., by reducing speed), the radiation frequency band of the patch antenna can be avoided. However, modifying the operating frequency of internal modules or their higher harmonic frequencies will likely sacrifice chip electrical performance, affecting product competitiveness.

[0005] 3) Encapsulate the internal or external periphery and add electromagnetic shielding material. Adding electromagnetic shielding material will increase costs.

[0006] Therefore, there is an urgent need for a technical solution that can solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a packaging shielding structure design method and a semiconductor packaging shielding structure, which reduces electromagnetic radiation of the semiconductor packaging structure and optimizes EMC performance while keeping costs low.

[0008] To achieve the above objectives, this invention provides a packaging and shielding structure design method. The semiconductor packaging structure includes a circuit board, a semiconductor component packaged on the circuit board, and a metal cover covering the semiconductor component. A patch antenna is formed between the circuit board and the metal cover. The packaging and shielding structure design method includes: Step 1, establishing a simulation model of the patch antenna; Step 2, simulating the field strength radiation diagram of the patch antenna to obtain the radiation frequency of the patch antenna. In the simulation model, observing the current distribution diagram of the inner surface of the metal cover at the radiation frequency to select the direction of the main current flow, and opening an auxiliary slot in the direction perpendicular to the direction of the main current flow on the metal cover to form a new patch antenna; Step 3, establishing a simulation model of the new patch antenna; Step 4, simulating the field strength radiation diagram of the patch antenna to obtain the new radiation frequency of the patch antenna, determining that the distance between the radiation frequency of the patch antenna and the main frequency of the semiconductor component is greater than or equal to a preset value, and if so, proceeding to Step 5. Otherwise, proceed to step 6; Step 5, output the design result with the current position and size of the auxiliary slot; Step 6, adjust the position and size of the auxiliary slot, or add a new auxiliary slot, and repeat step 4.

[0009] Preferably, in steps 2 and 4, simulating the field strength radiation map of the patch antenna includes: simulating the far-field radiation map of the patch antenna at a first preset distance as the field strength radiation map, or simulating the near-field radiation map of the patch antenna at a second preset distance, and using the far-field radiation map at the first preset distance obtained by equivalent transformation of the near-field radiation map as the field strength radiation map.

[0010] Preferably, in step 2, the current distribution map of the inner surface of each side of the metal cover at the radiation frequency is observed to select the direction through which the main current flows, and an auxiliary groove is opened on at least one side of the metal cover in a direction perpendicular to the direction through which the main current flows, so as to form a new patch antenna.

[0011] Specifically, the auxiliary groove is formed at least on the top surface of the metal cover opposite to the circuit board, and the auxiliary groove is strip-shaped.

[0012] Preferably, the simulation model of the patch antenna is established using a single signal line as the excitation source. The simulation model is simple and easy to simulate.

[0013] Preferably, the main frequency of the semiconductor component includes the internal signals, power supply, operating frequency of the internal modules, and the highest and second highest harmonics of the semiconductor component.

[0014] Preferably, in step 5, a thermal simulation model of the semiconductor packaging structure is established, and it is determined whether the thermal simulation result of the semiconductor packaging structure is qualified. If it is qualified, the simulation ends and the position and size of the current auxiliary slot are determined as the design result output. Otherwise, the size of the auxiliary slot is increased or the number of auxiliary slots is increased and step 4 is repeated.

[0015] Preferably, in step 2, the field strength radiation pattern of the patch antenna is simulated using a 3D full-wave simulation tool, and the current distribution pattern of the inner surface of the metal cover at the radiation frequency is observed.

[0016] Preferably, in step 6, for each new auxiliary slot, the position and size of the auxiliary slot are adjusted in the first n simulation iterations, and a new auxiliary slot is added in the (n+1)th simulation iteration, where n is greater than or equal to 1 and is a preset constant.

[0017] The present invention also provides a semiconductor packaging shielding structure, including a circuit substrate, a semiconductor component packaged on the circuit substrate, and a metal cover covering the semiconductor component. The metal cover has an auxiliary groove, and the size and position of the auxiliary groove are determined by the packaging shielding structure design method described above.

[0018] Compared with existing technologies, this invention uses simulation tools to simulate patch antennas, detects and determines the radiation frequency and current distribution of the patch antenna, and uses this to create auxiliary slots to effectively change the radiation frequency of the patch antenna, moving it away from the main frequency of the semiconductor component. Thus, without changing the package size or adjusting the package material, by simulating the patch antenna and creating auxiliary slots, the current distribution on the metal cover is changed, thereby changing the field distribution in the cavity between the metal cover and the circuit board. This ensures that the radiation frequency band of the patch antenna between the metal cover and the circuit board avoids the main operating frequency of the internal semiconductor component, thereby reducing electromagnetic radiation of the semiconductor package structure and optimizing EMC performance. Attached Figure Description

[0019] Figure 1 This is a flowchart of the encapsulation and shielding structure design method of the present invention.

[0020] Figure 2 It is a simulation model of a patch antenna.

[0021] Figure 3 This is a field strength radiation diagram of a patch antenna.

[0022] Figure 4 This is a current distribution diagram on the inner surface of the metal cover at the radiation frequency in the simulation model of the patch antenna.

[0023] Figure 5 This is a schematic diagram of an auxiliary groove cut along the direction of the metal cover.

[0024] Figure 6 This is a structural diagram of a semiconductor package. Detailed Implementation

[0025] To illustrate the technical content, structural features, objectives, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0026] refer to Figure 1 This invention discloses a method for designing an encapsulation shielding structure, with reference to... Figure 6 The semiconductor packaging structure includes a circuit substrate 10, a semiconductor component 20 packaged on the circuit substrate 10, and a metal cover 30 covering the semiconductor component 20. A patch antenna is formed between the circuit substrate 10 and the metal cover 20. The packaging shielding structure design method includes steps S1 to S8.

[0027] S1. Establish a simulation model of the patch antenna using a signal line as the excitation source.

[0028] Specifically, the signal strength and length of the signal lines are determined based on the areas of the circuit board 10 and the metal cover 20, the distance between the circuit board 10 and the metal cover 20, and the shape of the metal cover 20, thereby determining the excitation source of the patch antenna. [Kelong 1] refer to Figure 2 This is a simulation model of a patch antenna.

[0029] S2, simulate the field strength radiation diagram of the patch antenna to obtain the radiation frequency of the patch antenna.

[0030] In step S2, the field strength radiation pattern of the patch antenna is simulated using a 3D full-wave simulation tool.

[0031] refer to Figure 3 The graph shows the field strength radiation of the patch antenna, with frequency on the horizontal axis and radiation intensity on the vertical axis.

[0032] In step S2, simulating the field strength radiation map of the patch antenna includes: simulating the far-field radiation map of the patch antenna at a first preset distance as the field strength radiation map, or simulating the near-field radiation map of the patch antenna at a second preset distance, and using the far-field radiation map at the first preset distance obtained by equivalent transformation of the near-field radiation map as the field strength radiation map.

[0033] S3. In the simulation model, observe the current distribution map of the inner surface of the metal cover at the radiation frequency point to select the direction through which the main current flows. Open an auxiliary slot in the direction perpendicular to the direction through which the main current flows in the direction of the metal cover to form a new patch antenna.

[0034] The auxiliary slot is a preset size and preset administrative auxiliary slot, and its opening position is a preset initial position.

[0035] In step S3, the current distribution map of the inner surface of the metal cover at the radiation frequency is observed in the 3D full-wave simulation tool.

[0036] refer to Figure 4 This is a current distribution diagram on the inner surface of the metal cover at the radiation frequency in the simulation model of the patch antenna.

[0037] refer to Figure 5 This is a schematic diagram of auxiliary grooves opened along the direction on the metal cover, where the arrows indicate the direction of the main current flow.

[0038] In step S3, the current distribution diagram of the inner surface of each side of the metal cover at the radiation frequency is observed to select the direction through which the main current flows. An auxiliary groove is opened on at least one side of the metal cover in a direction perpendicular to the direction through which the main current flows to form a new patch antenna.

[0039] Specifically, the auxiliary groove is formed at least on the top surface of the metal cover opposite to the circuit board. In this embodiment, the auxiliary groove is rectangular; however, it can also be other strip-shaped grooves.

[0040] S4. Based on the size and position of the auxiliary slot, establish a new simulation model of the patch antenna.

[0041] Specifically, the signal strength and length of the signal line are determined based on the areas of the circuit board 10 and the metal cover 20, the distance between the circuit board 10 and the metal cover 20, and the shape of the metal cover 20 (the position, size, and shape of the auxiliary slots on the corresponding surface of the metal cover 20), thereby determining the excitation source of the patch antenna. [Kelong2] S5, simulate the field strength radiation diagram of the patch antenna to obtain the new radiation frequency of the patch antenna.

[0042] In step S5, simulating the field strength radiation map of the patch antenna includes: simulating the far-field radiation map of the patch antenna at a first preset distance as the field strength radiation map, or simulating the near-field radiation map of the patch antenna at a second preset distance, and using the far-field radiation map at the first preset distance obtained by equivalent transformation of the near-field radiation map as the field strength radiation map.

[0043] S6, determine whether the distance between the radiation frequency of the patch antenna and the main frequency of the semiconductor component is greater than or equal to a preset value, that is, determine whether the radiation frequency of the patch antenna is far away from the main frequency of the semiconductor component. If yes, proceed to step S7; otherwise, proceed to step S8.

[0044] The main frequency of the semiconductor component includes the internal signals, power supply, operating frequency of the internal modules, and the highest and second highest harmonics.

[0045] S7, end the simulation and determine the current position and size of the auxiliary slot as the design result output.

[0046] In step S7, a thermal simulation model of the semiconductor packaging structure is established, and it is determined whether the thermal simulation result of the semiconductor packaging structure is qualified. If it is, the simulation ends and the current position and size of the auxiliary slot are output as the design result. Otherwise, the size of the auxiliary slot is increased or the number of auxiliary slots is increased, and steps S4 to S6 are repeated.

[0047] S8, adjust the position and size of the auxiliary slot, or add a new auxiliary slot, and repeat steps S4 to S6 until the distance between the radiation frequency of the patch antenna and the main frequency of the semiconductor component is greater than or equal to a preset value.

[0048] In step S8, the adjustment of the position and size of the auxiliary slot follows a preset pattern, such as adding an auxiliary slot of a preset size or shifting the auxiliary slot a preset distance in a preset direction. When adding a new auxiliary slot, the position and size of the added auxiliary slot follow a preset pattern.

[0049] In step S8, for each new auxiliary slot, the position and size of the auxiliary slot are adjusted in the first n simulation iterations, and a new auxiliary slot is added in the (n+1)th simulation iteration, where n is greater than or equal to 1 and is a preset constant.

[0050] The present invention also discloses a semiconductor packaging shielding structure, including a circuit substrate 10, a semiconductor component 20 packaged on the circuit substrate 10, and a metal cover 30 covering the semiconductor component 20. The metal cover 30 has an auxiliary groove (not shown in the figure), and the size and position of the auxiliary groove are determined by the packaging shielding structure design method described above.

[0051] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the scope of the present invention are still within the scope of the present invention.

Claims

1. A method for designing a packaged shielding structure, wherein the semiconductor package structure includes a circuit substrate, a semiconductor component packaged on the circuit substrate, and a metal cover covering the semiconductor component, wherein a patch antenna is formed between the circuit substrate and the metal cover, characterized in that: include: Step 1: Establish a simulation model of the patch antenna; Step 2: Simulate the field strength radiation pattern of the patch antenna to obtain the radiation frequency of the patch antenna. In the simulation model, observe the current distribution pattern of the inner surface of the metal cover at the radiation frequency to select the direction through which the main current flows. Open an auxiliary slot in the direction perpendicular to the direction through which the main current flows in the direction of the metal cover to form a new patch antenna. Step 3: Establish a new simulation model of the patch antenna; Step 4: Simulate the field strength radiation pattern of the patch antenna to obtain a new radiation frequency of the patch antenna. Determine that the distance between the radiation frequency of the patch antenna and the main frequency of the semiconductor component is greater than or equal to a preset value. If so, proceed to step 5; otherwise, proceed to step 6. Step 5: Output the design result with the current position and size of the auxiliary slot; Step 6: Adjust the position and size of the auxiliary slot, or add a new auxiliary slot, and repeat step 4.

2. The package shield structure design method of claim 1, wherein: In steps 2 and 4, the simulated field strength radiation pattern of the patch antenna includes: The far-field radiation map of the patch antenna at a first preset distance is simulated as the field strength radiation map, or the near-field radiation map of the patch antenna at a second preset distance is simulated, and the far-field radiation map at the first preset distance obtained by equivalent transformation of the near-field radiation map is used as the field strength radiation map.

3. The method of designing a package shielding structure of claim 1, wherein: In step 2, the current distribution diagram of the inner surface of each side of the metal cover at the radiation frequency is observed to select the direction through which the main current flows. An auxiliary groove is opened on at least one side of the metal cover in a direction perpendicular to the direction through which the main current flows to form a new patch antenna.

4. The method of designing a package shielding structure of claim 3, wherein: The auxiliary groove is formed at least on the top surface of the metal cover opposite to the circuit board, and the auxiliary groove is elongated.

5. The method of designing a package shielding structure of claim 1, wherein: A simulation model of the patch antenna is established using a signal line as the excitation source.

6. The method of designing a package shielding structure of claim 1, wherein: The main frequency of the semiconductor component includes the internal signals, power supply, operating frequency of the internal modules, and the highest and second highest harmonics.

7. The method of designing a package shielding structure of claim 1, wherein: In step 5, a thermal simulation model of the semiconductor packaging structure is established, and it is determined whether the thermal simulation result of the semiconductor packaging structure is qualified. If it is qualified, the simulation ends and the position and size of the current auxiliary slot are determined as the design result output. Otherwise, the size of the auxiliary slot is increased or the number of auxiliary slots is increased and step 4 is repeated.

8. The method of designing a package shielding structure of claim 1, wherein: In step 2, the field strength radiation pattern of the patch antenna is simulated using a 3D full-wave simulation tool, and the current distribution pattern of the inner surface of the metal cover at the radiation frequency is observed.

9. The encapsulation shielding structure design method as described in claim 1, characterized in that: In step 6, for each new auxiliary slot, the position and size of the auxiliary slot are adjusted in the first n simulation iterations, and a new auxiliary slot is added in the (n+1)th simulation iteration, where n is greater than or equal to 1 and is a preset constant.

10. A semiconductor packaging shielding structure, characterized in that: The device includes a circuit board, a semiconductor component packaged on the circuit board, and a metal cover covering the semiconductor component. The metal cover has an auxiliary groove, and the size and position of the auxiliary groove are determined by the packaging shielding structure design method according to any one of claims 1-9.

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