An anti-static protection device for semiconductor devices

Abstract

This invention belongs to the field of semiconductor device protection technology, specifically referring to an anti-electrostatic discharge (ESD) protection device for semiconductor devices. It includes a protective body, an ESD detection module, an adaptive control module, a composite discharge module, a shielding module, and a connection interface. The ESD detection module, adaptive control module, composite discharge module, and connection interface are signal-connected. The protective body adopts a 4H-SiC substrate structure. A buffer layer, an insulating layer, and a metal interconnect layer are sequentially grown on the surface of the 4H-SiC substrate. The buffer layer is used to reduce stress between the substrate and the upper structure. The ESD detection module is fixedly installed on one side of the protective body, and the adaptive control module is fixedly installed on the other side. The composite discharge module is embedded between the metal interconnect layer and the insulating layer of the protective body. This device achieves low triggering, high sustaining, and uniform current distribution, and can adaptively adjust the ESD discharge efficiency, effectively preventing device latch-up and breakdown, thus improving protection performance and practicality.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor device protection technology, specifically referring to an anti-static protection device for semiconductor devices. Background Technology

[0002] As semiconductor technology advances towards higher integration, shorter gate lengths, and thinner gate oxide layers, the sensitivity of semiconductor devices to static electricity has increased significantly. Electrostatic discharge (ESD) has become one of the main causes of damage and failure in semiconductor devices. During the production, transportation, assembly, and use of semiconductor devices, the electrostatic potential generated by the human body, equipment, and environment can reach 5000-10000 volts. The instantaneous release of high energy can cause a rapid increase in the local temperature inside the device, leading to changes in the crystal structure of the semiconductor material, triggering problems such as hot carrier effects and metal migration, and even directly breaking down the gate oxide layer, causing complete device failure.

[0003] Currently, existing electrostatic discharge (ESD) protection technologies for semiconductor devices mainly fall into two categories: one is based on silicon controlled rectifiers (SCRs), which suffers from problems such as latch-up due to excessively high trigger voltages and excessively low sustaining voltages; the other is based on gate-grounded NMOS (GGNMOS), which, while improving the sustaining voltage to some extent, suffers from uneven current distribution, insufficient robustness, and severe bounce phenomena. Furthermore, existing protection devices mostly employ a single discharge path, failing to adaptively adjust discharge efficiency according to ESD intensity. In addition, unreasonable connection methods between protection devices and core semiconductor devices lead to delayed ESD discharge, still causing damage to the core devices. Moreover, for protection devices of wide-bandgap semiconductor materials such as 4H-SiC, an effective solution that balances robustness and process compatibility has not yet been developed, making it difficult to meet the protection requirements of high-voltage, high-power scenarios. Summary of the Invention

[0004] To address the problems of high trigger voltage, low sustaining voltage, high latch-up risk, uneven current distribution, unadjustable discharge efficiency, and unreliable connection in existing semiconductor device electrostatic discharge (ESD) protection devices, this invention provides an ESD protection device for semiconductor devices. This device employs a composite discharge structure combining a comb-shaped HHFGNMOS and a low-trigger, high-sustain SCR to achieve low triggering, high sustaining, and uniform current distribution. It can adaptively adjust the ESD discharge efficiency, effectively preventing device latch-up and breakdown, and improving protection performance and practicality.

[0005] To achieve the above functions, the technical solution adopted by the present invention is as follows: A semiconductor device anti-static protection device includes a protective body, an electrostatic detection module, an adaptive control module, a composite discharge module, a shielding module, and a connection interface. The electrostatic detection module, the adaptive control module, the composite discharge module, and the connection interface are signal-connected. The protective body adopts a 4H-SiC substrate structure. A buffer layer, an insulating layer, and a metal interconnect layer are sequentially grown on the surface of the 4H-SiC substrate. The buffer layer is used to reduce the stress between the substrate and the upper structure. The insulating layer is made of silicon oxide material to achieve electrical isolation between the components. The metal interconnect layer is made of aluminum-copper alloy. The protective body is used to realize signal and current transmission between modules; a core device mounting area is reserved in the middle of the protective body for placing the semiconductor core device to be protected. The core device is connected to the metal interconnect layer through metal bonding wires to realize electrical conduction with each module of the protective device; the electrostatic detection module is fixedly installed on one side of the protective body and is fixedly connected to the metal interconnect layer; the adaptive control module is fixedly installed on the other side of the protective body and is fixedly connected to the metal interconnect layer; the composite discharge module is embedded between the metal interconnect layer and the insulating layer of the protective body, located on the periphery of the core device mounting area, and is distributed in a ring.

[0006] As a preferred embodiment of the present invention, the electrostatic detection module includes an electrostatic sensor, a signal amplification unit, and a filtering unit. The electrostatic sensor adopts a comb-shaped electrode structure with an electrode spacing of 2-5 μm, and is used to detect electrostatic charge and electrostatic voltage on the surface of the environment and core components in real time. The output terminal of the electrostatic sensor is connected to the input terminal of the signal amplification unit through a metal interconnect layer. The signal amplification unit adopts a differential amplifier circuit to amplify the weak electrostatic signal detected by the electrostatic sensor. The output terminal of the signal amplification unit is connected to the input terminal of the filtering unit. The filtering unit adopts an RC low-pass filter circuit to filter out high-frequency interference in the electrostatic signal. The output terminal of the filtering unit is connected to the input terminal of the adaptive control module through a metal interconnect layer to realize the transmission of the detection signal.

[0007] In a preferred embodiment of the present invention, the adaptive control module includes a control chip, a voltage comparison unit, and a drive unit. The input terminal of the control chip is connected to the output terminal of the filter unit of the electrostatic detection module to receive electrostatic detection signals. The control chip internally presets two voltage thresholds, corresponding to low-intensity electrostatic discharge and high-intensity electrostatic discharge, respectively. The voltage comparison unit is integrated inside the control chip and is used to compare the detected electrostatic voltage with the preset thresholds and output a comparison signal. The input terminal of the drive unit is connected to the output terminal of the control chip. The drive unit uses a MOS transistor drive circuit to adjust the discharge path and discharge efficiency of the composite discharge module according to the control signal output by the control chip. The output terminal of the drive unit is connected to the control terminal of the composite discharge module through a metal interconnect layer.

[0008] As a preferred embodiment of the present invention, the composite discharge module includes a comb-shaped HHFGNMOS discharge unit, an SCR discharge unit, and a shunt adjustment unit. The comb-shaped HHFGNMOS discharge unit adopts a comb-shaped drain structure, which fully utilizes the current edge effect to achieve uniform current distribution. Its drain is connected to the output terminal of the core device through a metal interconnect layer, its source is connected to the input terminal of the shunt adjustment unit, and its gate is connected to the output terminal of the drive unit of the adaptive control module. The SCR discharge unit adopts a low-trigger, high-sustain structure, bridging the first N-well and the first P-well. A P-type injection region is added below the third N+ injection region to shift the avalanche breakdown surface and reduce the trigger voltage. Its anode is connected to the output terminal of the core device, and its cathode is connected to the input terminal of the shunt adjustment unit. The shunt adjustment unit adopts a multi-group parallel MOS transistor structure. Its input terminal is connected to the source of the comb-shaped HHFGNMOS discharge unit and the cathode of the SCR discharge unit, respectively. Its output terminal is connected to the ground terminal. The control terminal of the shunt adjustment unit is connected to the output terminal of the drive unit of the adaptive control module, which is used to adjust the current distribution ratio of the two groups of discharge units according to the control signal.

[0009] As a preferred embodiment of the present invention, the shielding module is wrapped around the outer surface of the protective body and adopts a metal shielding shell structure. The metal shielding shell structure is made of copper alloy material, and its inner wall is fixedly connected to the edge of the protective body by conductive adhesive. At the same time, the metal shielding shell is connected to the grounding terminal of the composite discharge module through a grounding pin to shield external electromagnetic interference and electrostatic radiation, and to prevent external static electricity from affecting the core components through spatial coupling.

[0010] In a preferred embodiment of the present invention, the connection interface is located at the end of the protective body and is electrically connected to the metal interconnect layer. The connection interface includes a power interface, a signal interface, and a grounding interface. The power interface provides operating power to the electrostatic detection module and the adaptive control module. Its input end is connected to an external power source, and its output end is electrically connected to the power supply terminals of the two modules. The signal interface is used to realize signal transmission between the core device and the external circuit. One end is connected to the signal terminal of the core device, and the other end is connected to the external circuit. The grounding interface is electrically connected to the grounding terminal of the composite discharge module and the grounding pin of the shielding module to discharge electrostatic charge to the ground and ensure low impedance of the discharge path.

[0011] As a preferred embodiment of the present invention, the comb-shaped drain region width of the comb-shaped HHFGNMOS discharge unit is 10-20μm, and the tooth pitch is 5-8μm; the trigger voltage of the SCR discharge unit is controlled at 5-8V, and the sustaining voltage is controlled at 12-15V, effectively avoiding latch-up problems.

[0012] As a preferred embodiment of the present invention, the control chip of the adaptive control module adopts an MCU microcontroller with a response time ≤1ns, which can quickly identify the electrostatic intensity and output a control signal. When the detected electrostatic voltage is lower than the low threshold, the drive unit controls the composite discharge module to be in standby mode, and only activates the weak discharge channel of the comb-shaped HHFGNMOS discharge unit. When the electrostatic voltage is between the low threshold and the high threshold, the drive unit controls the comb-shaped HHFGNMOS discharge unit to start at full capacity and the SCR discharge unit to start partially, achieving medium-efficiency discharge. When the electrostatic voltage is higher than the high threshold, the drive unit controls the comb-shaped HHFGNMOS discharge unit and the SCR discharge unit to start at full capacity, and the current distribution ratio of the two is adjusted to 1:1.5 by the current shunt adjustment unit to achieve high-efficiency discharge.

[0013] As a preferred embodiment of the present invention, the thickness of the metal interconnect layer is 0.5-1 μm, and the surface is coated with a titanium-tungsten barrier layer to prevent metal diffusion and improve connection reliability; the thickness of the insulating layer is 1-2 μm, and it is prepared by plasma-enhanced chemical vapor deposition to ensure electrical isolation performance; the comb-shaped electrode of the electrostatic sensor is made of polycrystalline silicon material and prepared by ion implantation, with a detection accuracy of 0.1V and a detection range of 0-20kV, which can accurately detect electrostatic signals of different intensities.

[0014] Compared with the prior art, the present invention achieves the following beneficial effects by adopting the above structure: 1. The device employs a 4H-SiC substrate with a multilayer metal interconnect and insulating layer structure, combined with an integrated shielding design, which effectively improves the overall structural stability and anti-interference capability of the device and achieves source isolation from external static electricity and electromagnetic radiation. 2. By using a comb-shaped electrode electrostatic sensor and a high-precision RC filter circuit, real-time and accurate electrostatic detection with a wide range of 0-20kV and a high resolution of 0.1V is achieved, providing a reliable signal basis for adaptive control; 3. The adaptive control module uses an MCU with a response time of ≤1ns as its core. Based on the dynamic adjustment of dual voltage thresholds, it enables the composite discharge module to switch working modes as needed, achieving graded, precise, and efficient discharge under low, medium, and high electrostatic discharge strengths. The composite discharge module adopts a combination of comb-shaped HHFGNMOS and low-trigger, high-sustain SCR units, along with a shunt adjustment structure. On the one hand, it increases the secondary failure current by more than 25% and reduces the bounce phenomenon by more than 50%. On the other hand, it controls the trigger voltage and sustaining voltage within a reasonable range, effectively avoiding latch-up effects and significantly improving the reliability and stability of the discharge process. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of an anti-static protection device for semiconductor devices proposed in this invention; Figure 2 This is a schematic diagram of the structure of a composite discharge module for an anti-static protection device for semiconductor devices proposed in this invention; Figure 3 This is a block diagram showing the connection relationship of the various modules of the anti-static protection device for semiconductor devices proposed in this invention.

[0016] The components include: 1. Protective body; 11. Buffer layer; 12. Insulation layer; 13. Metal interconnection layer; 2. Electrostatic detection module; 3. Adaptive control module; 4. Composite discharge module; 5. Shielding module; 6. Connection interface; 61. Power interface; 62. Signal interface; 63. Grounding interface; 64. Grounding pin. Detailed Implementation

[0017] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The invention will be further described in detail below with reference to the accompanying drawings. Example 1:

[0019] like Figures 1-3 As shown, an anti-static protection device for semiconductor devices is applicable to consumer electronic semiconductor devices such as mobile phone chips. The specific structure is as follows: The protective body 1 adopts a 4H-SiC substrate with a thickness of 300μm. A buffer layer 11 (thickness 50nm), an insulating layer 12 (thickness 1μm, silicon oxide material, prepared by PECVD process) and a metal interconnect layer 13 (thickness 0.5μm, aluminum-copper alloy, with a titanium-tungsten barrier layer plated on the surface) are grown sequentially on the surface. The core device mounting area is located in the middle of the protective body 1 and is used to place the core device of the mobile phone chip. The core device is electrically connected to the metal interconnect layer 13 through metal bonding wires.

[0020] The electrostatic detection module 2 is installed on the left side of the protective body 1. The electrostatic sensor uses comb-shaped polycrystalline silicon electrodes with an electrode spacing of 2μm, a detection range of 0-10kV, and a detection accuracy of 0.1V. The signal amplification unit uses a differential amplifier circuit with a magnification factor of 100 times. The filtering unit uses an RC low-pass filter circuit (resistor 1kΩ, capacitor 100pF). The output terminal of the electrostatic sensor is connected to the input terminal of the signal amplification unit through a metal interconnect layer 13. The output terminal of the signal amplification unit is connected to the input terminal of the filtering unit. The output terminal of the filtering unit is connected to the input terminal of the adaptive control module 3.

[0021] The adaptive control module 3 is installed on the right side of the protective body 1. The control chip is an MCU microcontroller (model STM32L431) with a response time of 0.8ns and preset low threshold of 3V and high threshold of 8V. The voltage comparison unit is integrated inside the control chip. The drive unit uses a MOS transistor drive circuit (model IR2110). The input terminal of the control chip is connected to the output terminal of the filter unit, the input terminal of the drive unit is connected to the output terminal of the control chip, and the output terminal of the drive unit is connected to the control terminal of the composite discharge module 4.

[0022] The composite discharge module 4 is embedded between the metal interconnect layer 13 and the insulating layer 12, and is distributed in a ring around the core device mounting area. The comb-shaped HHFGNMOS discharge unit has a comb-shaped drain region width of 10μm and a tooth pitch of 5μm. The drain is connected to the output terminal of the core device, the source is connected to the input terminal of the shunt adjustment unit, and the gate is connected to the output terminal of the drive unit. The SCR discharge unit has a trigger voltage of 5V and a sustaining voltage of 12V. The anode is connected to the output terminal of the core device, and the cathode is connected to the input terminal of the shunt adjustment unit. The shunt adjustment unit uses two sets of parallel MOS transistors (model IRF3205). The input terminals are connected to the source of the comb-shaped HHFGNMOS discharge unit and the cathode of the SCR discharge unit, respectively. The output terminal is connected to the ground terminal, and the control terminal is connected to the output terminal of the drive unit.

[0023] The shielding module 5 uses a copper alloy shielding shell, which covers the outer surface of the protective body 1. The inner wall is connected to the edge of the protective body 1 through conductive adhesive. The shielding shell is connected to the grounding terminal of the composite discharge module 4 through the grounding pin 64.

[0024] The connection interface 6 is located at the end of the protective body 1. The power interface 61 has an input voltage of 3.3V, which powers the electrostatic detection module 2 and the adaptive control module 3. The signal interface 62 uses a USB interface to realize signal transmission between the core device and the external circuit. The grounding interface 63 is connected to the grounding terminal of the composite discharge module 4 and the grounding pin 64 of the shielding module 5, with a grounding impedance ≤1Ω.

[0025] The working process of this embodiment is as follows: The shielding module 5 shields external electromagnetic interference and electrostatic radiation in real time; after the electrostatic sensor detects the electrostatic voltage on the surface of the mobile phone chip, it is amplified by the signal amplification unit and filtered by the filtering unit before being transmitted to the control chip; when the electrostatic voltage is 2V (below the low threshold of 3V), the control chip controls the drive unit to output a low level, the composite discharge module 4 is in standby mode, and only the comb-shaped HHFGNMOS discharge unit starts a weak discharge channel; when the electrostatic voltage is 5V (between the low threshold and the high threshold), the drive unit controls the comb-shaped HHFGNMOS discharge unit to start at full capacity and the SCR discharge unit to start partially, achieving medium-efficiency discharge; when the electrostatic voltage is 10V (above the high threshold of 8V), the drive unit controls the comb-shaped HHFGNMOS discharge unit and the SCR discharge unit to start at full capacity, and the current distribution unit adjusts the current distribution ratio of the two to 1:1.5, quickly discharging the electrostatic charge to the ground through the grounding interface 63, thus achieving effective protection for the mobile phone chip. Example 2:

[0026] An anti-static protection device for semiconductor devices is disclosed, suitable for high-voltage, high-power 4H-SiC semiconductor devices. The specific structure is basically the same as in Embodiment 1, except that: the insulating layer 12 of the protective body 1 has a thickness of 2μm, and the metal interconnect layer 13 has a thickness of 1μm; the detection range of the electrostatic sensor is 0-20kV, and the electrode spacing is 5μm; the control chip has a preset low threshold of 5V, a high threshold of 12V, and a response time of 1ns; the comb-shaped HHFGNMOS discharge unit has a comb-shaped drain region width of 20μm and a tooth pitch of 8μm, increasing the secondary failure current by 29% compared to traditional GGNMOS and reducing bounce by 55.2%; the SCR discharge unit has a trigger voltage of 8V and a sustaining voltage of 15V; the shunt adjustment unit uses three sets of parallel MOS transistors, and the current distribution ratio can be adjusted to 1:2; the grounding impedance of the grounding interface 63 is ≤0.5Ω, ensuring rapid discharge of high-voltage electrostatic discharge.

[0027] The protective device in this embodiment can effectively resist strong electrostatic shocks in high-voltage and high-power scenarios, prevent 4H-SiC semiconductor devices from failing due to electrostatic breakdown, and improve the reliability of the devices in high-temperature and high-pressure environments.

[0028] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. An anti-static protection device for semiconductor devices, characterized in that: The system includes a protective body (1), an electrostatic detection module (2), an adaptive control module (3), a composite discharge module (4), a shielding module (5), and a connection interface (6). The electrostatic detection module (2), the adaptive control module (3), the composite discharge module (4), and the connection interface (6) are connected by signals. The protective body (1) adopts a 4H-SiC substrate structure. A buffer layer (11), an insulating layer (12), and a metal interconnect layer (13) are sequentially grown on the surface of the 4H-SiC substrate. The insulating layer (12) is made of silicon oxide material, and the metal interconnect layer (13) is made of silicon oxide material. Aluminum-copper alloy; the protective body (1) has a reserved core device installation area in the middle; the electrostatic detection module (2) is fixedly installed on one side of the protective body (1), and the electrostatic detection module (2) is fixedly connected to the metal interconnect layer (13); the adaptive control module (3) is fixedly installed on the other side of the protective body (1), and the adaptive control module (3) is fixedly connected to the metal interconnect layer (13); the composite discharge module (4) is embedded between the metal interconnect layer (13) and the insulating layer (12) of the protective body (1), located on the periphery of the core device installation area, and is distributed in a ring.

2. The anti-static protection device for semiconductor devices according to claim 1, characterized in that: The electrostatic detection module (2) includes an electrostatic sensor, a signal amplification unit, and a filtering unit. The electrostatic sensor adopts a comb-shaped electrode structure. The output end of the electrostatic sensor is connected to the input end of the signal amplification unit through a metal interconnect layer (13). The signal amplification unit adopts a differential amplifier circuit. The output end of the signal amplification unit is connected to the input end of the filtering unit. The filtering unit adopts an RC low-pass filter circuit. The output end of the filtering unit is connected to the input end of the adaptive control module (3) through a metal interconnect layer (13).

3. The anti-static protection device for semiconductor devices according to claim 2, characterized in that: The adaptive control module (3) includes a control chip, a voltage comparison unit and a drive unit. The input terminal of the control chip is connected to the output terminal of the filter unit of the electrostatic detection module (2). The control chip has two preset voltage thresholds. The voltage comparison unit is integrated inside the control chip. The input terminal of the drive unit is connected to the output terminal of the control chip. The drive unit uses a MOS transistor drive circuit. The output terminal of the drive unit is connected to the control terminal of the composite discharge module (4) through a metal interconnect layer (13).

4. The anti-static protection device for semiconductor devices according to claim 3, characterized in that: The composite discharge module (4) includes a comb-shaped HHFGNMOS discharge unit, an SCR discharge unit, and a shunt adjustment unit; the drain of the comb-shaped HHFGNMOS discharge unit is connected to the output terminal of the core device, the source is connected to the input terminal of the shunt adjustment unit, and the gate is connected to the output terminal of the drive unit of the adaptive control module (3); the anode of the SCR discharge unit is connected to the output terminal of the core device, and the cathode is connected to the input terminal of the shunt adjustment unit. The output terminal of the shunt adjustment unit is connected to the ground terminal, and the control terminal is connected to the output terminal of the drive unit of the adaptive control module (3). The SCR discharge unit has a P-type injection region below the third N+ injection region that bridges the first N-well and the first P-well.

5. The anti-static protection device for semiconductor devices according to claim 4, characterized in that: The shielding module (5) is wrapped around the outer surface of the protective body (1) and adopts a metal shielding shell structure. The metal shielding shell structure is made of copper alloy material. Its inner wall is fixedly connected to the edge of the protective body (1) by conductive adhesive. At the same time, the metal shielding shell is connected to the grounding terminal of the composite discharge module (4) through the grounding pin (64).

6. The anti-static protection device for semiconductor devices according to claim 5, characterized in that: The connection interface (6) is located at the end of the protective body (1) and is electrically connected to the metal interconnect layer (13). It includes a power interface (61), a signal interface (62), and a ground interface (63). The input end of the power interface (61) is connected to an external power source, and the output end is electrically connected to the power source of the electrostatic detection module (2) and the adaptive control module (3). One end of the signal interface (62) is connected to the signal end of the core device, and the other end is connected to an external circuit. The ground interface (63) is electrically connected to the ground end of the composite discharge module (4) and the ground pin (64) of the shielding module (5).

7. The anti-static protection device for semiconductor devices according to claim 4, characterized in that: The comb-shaped HHFGNMOS discharge unit has a drain region width of 10-20μm and a tooth pitch of 5-8μm; the trigger voltage of the SCR discharge unit is controlled at 5-8V and the sustaining voltage is controlled at 12-15V.

8. The anti-static protection device for semiconductor devices according to claim 3, characterized in that: The control chip of the adaptive control module (3) is an MCU microcontroller.

9. The anti-static protection device for semiconductor devices according to claim 2, characterized in that: The metal interconnect layer (13) has a thickness of 0.5-1 μm and is coated with a titanium-tungsten barrier layer. The insulating layer (12) has a thickness of 1-2 μm. The comb-shaped electrode of the electrostatic sensor is made of polycrystalline silicon.

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