ESD co-integration method for GaAs RF IC

Abstract

The application discloses an ESD cooperative integration method for a GaAs radio frequency integrated circuit. The method comprises the following steps: determining a center frequency according to a working frequency band of a radio frequency path, and calibrating a parasitic capacitance and an ESD discharge capacity; configuring parameters of a frequency selective coupling structure, so that different impedance states are corresponded under the working frequency band and electrostatic shock conditions; configuring parameters of a capacitive coupling trigger structure, so that a capacitive coupling is formed with a radio frequency port and a control end of an ESD discharge unit is connected; configuring parameters of a nonlinear coupling structure, so that a high resistance state is kept in a first voltage interval and a low resistance state is kept in a second voltage interval; an indirect connection relationship between the radio frequency path and the ESD discharge unit is constructed through a coupling interface unit, so that the ESD discharge unit is isolated from the radio frequency path under a radio frequency working state; under the electrostatic shock conditions, the ESD discharge unit is turned on, and a discharge path is formed through a reference potential node.

Description

Technical Field

[0001] This application relates to ESD structure design of radio frequency integrated circuits, and more particularly to an ESD co-integration method for GaAs radio frequency integrated circuits. Background Technology

[0002] In radio frequency (RF) integrated circuits, devices based on gallium arsenide (GaAs) technology are widely used in RF signal processing applications due to their excellent high-frequency characteristics. These circuits typically connect directly to external signal interfaces at the RF port, requiring high stability in signal transmission characteristics.

[0003] Meanwhile, to improve the reliability of devices during manufacturing, packaging and use, it is usually necessary to set an electrostatic discharge (ESD) protection structure at the radio frequency port to provide a current discharge path when an electrostatic shock occurs.

[0004] In the prior art, the ESD protection structure is usually directly associated with the radio frequency (RF) signal path. Since the RF signal path is sensitive to changes in additional electrical characteristics, and the ESD protection structure inevitably affects the RF signal path when implementing electrostatic discharge, a certain degree of mutual constraint exists between RF performance and ESD protection.

[0005] Therefore, in GaAs RF integrated circuits, how to balance the introduction of ESD protection structures with the maintenance of RF signal transmission characteristics still needs further improvement. Summary of the Invention

[0006] To address the aforementioned technical issues, this application provides an ESD co-integration method for GaAs radio frequency integrated circuits.

[0007] The technical solution provided in this application is described below:

[0008] The first aspect of this application provides an ESD co-integration method for GaAs radio frequency integrated circuits. The method is applied to GaAs radio frequency integrated circuits, which include a radio frequency port, a radio frequency path electrically connected to the radio frequency port, an ESD discharge unit, and a reference potential node. A coupling interface unit that does not constitute a DC conduction path is provided between the radio frequency path and the ESD discharge unit. The coupling interface unit includes a frequency-selective coupling structure, a nonlinear coupling structure, and a capacitively coupled triggering structure. The method includes: The center frequency is determined based on the operating frequency band of the radio frequency path, and the parasitic tolerance and ESD discharge capability are calibrated. Configure the parameters of the frequency-selective coupling structure so that it corresponds to different impedance states under the operating frequency band and electrostatic shock conditions; Configure the parameters of the capacitive coupling trigger structure to form a capacitive coupling with the RF port and connect it to the control terminal of the ESD discharge unit; The parameters of the nonlinear coupling structure are configured such that it is in a high-resistance state in the first voltage range and in a low-resistance state in the second voltage range. The coupling interface unit establishes an indirect connection between the radio frequency path and the ESD discharge unit, thereby isolating the ESD discharge unit from the radio frequency path during radio frequency operation. Under electrostatic discharge conditions, the ESD discharge unit is turned on, and a discharge path is formed through the reference potential node.

[0009] Optionally, determining the center frequency based on the operating frequency band of the radio frequency path and calibrating the parasitic tolerance and ESD discharge capability includes: Based on the target operating frequency band of the radio frequency path, the corresponding center frequency and frequency band range are extracted. Within the specified frequency band, the impedance matching characteristics of the radio frequency path are analyzed based on the equivalent parasitic parameters, and the upper limit of the allowable parasitic loading range is determined. Based on the preset ESD protection level, the target discharge current range under electrostatic shock conditions is determined. Based on the current transmission path from the radio frequency path to the reference potential node, the equivalent path impedance of the current transmission path is analyzed to determine the impedance constraint conditions that satisfy the target discharge current range. Based on the parasitic loading upper limit range and the impedance constraint condition, the parameter constraint range for configuring the coupling interface unit is determined.

[0010] Optionally, the parameter constraint range includes at least: Parasitic coupling parameter constraints used to limit the radio frequency path; Path impedance parameter constraints used to meet electrostatic discharge capability; Trigger parameter constraints used to control ESD triggering behavior; The parasitic coupling parameter constraints, path impedance parameter constraints, and trigger parameter constraints are interrelated, so that the coupling interface unit exhibits different conduction characteristics in the radio frequency operating state and the electrostatic shock state, respectively.

[0011] Optionally, the step of establishing an indirect connection between the RF path and the ESD discharge unit through the coupling interface unit, so that the ESD discharge unit is isolated from the RF path in the RF operating state, includes: The capacitively coupled trigger structure is connected to the control terminal of the ESD discharge unit, so that the capacitively coupled trigger structure is arranged in a non-overlapping manner with the radio frequency path in space. The frequency selective coupling structure is disposed between the radio frequency path and the reference potential node, and is disposed in layers with the capacitive coupling trigger structure; The nonlinear coupling structure is connected in series in the main current path of the ESD discharge unit and is located between the frequency selective coupling structure and the reference potential node; The capacitively coupled triggering structure, the frequency-selective coupling structure, and the nonlinear coupling structure are arranged in a spatial layout corresponding to the triggering region, the impedance-controlled region, and the current-conducting region, respectively.

[0012] Optionally, the step of turning on the ESD discharge unit under electrostatic discharge conditions and forming a discharge path through the reference potential node includes: When the ESD discharge unit is turned on, a main current transmission path is established between the radio frequency path and the reference potential node through the nonlinear coupling structure. The equivalent impedance of the main current transmission path is adjusted by the frequency-selective coupling structure so that the main current transmission path meets the impedance constraint condition under electrostatic shock conditions. The main current transmission path is connected to the reference potential node by a vertical via array, wherein the vertical via array is distributed along the boundary region of the coupling interface unit to form a surrounding current discharge channel around the coupling interface unit, and the vertical via array is discretely distributed in the circumferential direction of the coupling interface unit. The main current transmission path is connected to the reference potential node by a vertical via array, forming a current discharge channel along the thickness direction. The connection area between the main current transmission path and the radio frequency path is defined within the coupling interface unit.

[0013] Optionally, the parameters of the frequency-selective coupling structure are configured such that different impedance states correspond to the operating frequency band and electrostatic discharge (ESD) conditions, including: The frequency selective coupling structure is configured as at least two resonant units distributed along the radio frequency path, each resonant unit corresponding to different equivalent inductance and capacitance parameters; The resonant units are arranged at spatial intervals and indirectly coupled through the radio frequency path; By adjusting the parameter combination of the resonant unit, the frequency-selective coupling structure can exhibit high impedance characteristics within the operating frequency band. By adjusting the connection relationship of the resonant unit, the frequency-selective coupling structure can form an equivalent low-impedance path in the low-frequency range corresponding to electrostatic shock.

[0014] Optionally, configuring the parameters of the nonlinear coupling structure such that it is in a high-resistance state in a first voltage range and a low-resistance state in a second voltage range includes: The nonlinear coupling structure is constructed as a hierarchical conduction structure formed by multiple nonlinear units connected in series and / or in parallel, with each nonlinear unit corresponding to a different conduction threshold. The connection order and parameter combination of the multiple nonlinear units are adjusted so that the graded conduction structure exhibits a high-resistance state in the first voltage range and enters the conduction state step by step in the second voltage range.

[0015] Optionally, the frequency-selective coupling structure and the capacitive coupling trigger structure in the coupling interface unit are respectively disposed in different metal layers, and at least a portion of the nonlinear coupling structure is disposed across adjacent metal layers and electrically connected through a vertical via array; the capacitive coupling trigger structure is disposed opposite to the radio frequency path in the vertical direction; the frequency-selective coupling structure is located in the non-same-layer metal structure of the radio frequency path and forms electromagnetic coupling with the radio frequency path; the nonlinear coupling structure is located in the interlayer connection path between the frequency-selective coupling structure and the reference potential node.

[0016] Optionally, the spatial arrangement of the coupling interface units satisfies the following relationship: The capacitively coupled triggering structure at least partially covers the frequency-selective coupling structure on the planar projection and forms an overlapping coupling region in the vertical direction; the nonlinear coupling structure is disposed on the current transmission path corresponding to the overlapping coupling region, so that the overlapping coupling region simultaneously constitutes the triggering area and the conduction control area; a preset distance is maintained between the radio frequency path and the overlapping coupling region.

[0017] Optionally, the capacitively coupled trigger structure includes at least one pair of oppositely arranged first and second electrodes, the first electrode being connected to the radio frequency path, and the second electrode being connected to the control terminal of the ESD discharge unit; at least a portion of the edges of the first and second electrodes are arranged parallel to the conductor boundary of the radio frequency path.

[0018] As can be seen from the above technical solutions, this application has the following beneficial effects: 1. This application constructs a coupling interface unit that does not constitute a DC conduction path between the radio frequency path and the ESD discharge unit, and sets up a frequency selective coupling structure, a nonlinear coupling structure and a capacitive coupling trigger structure in the coupling interface unit to form a controlled indirect connection relationship between the radio frequency path and the ESD discharge path, thereby making the radio frequency circuit exhibit differentiated electrical connection characteristics under different operating conditions.

[0019] 2. In the RF operating state, the coupling interface unit as a whole presents high impedance isolation characteristics to the RF path, so that the ESD discharge unit does not participate in the RF signal transmission, thereby reducing the loading impact on the RF path; while under electrostatic shock conditions, through the synergistic effect of the capacitive coupling trigger structure and the nonlinear coupling structure, the ESD discharge unit is triggered to conduct, and with the participation of the frequency selective coupling structure, a current path that meets the discharge requirements is formed, thereby realizing the effective release of electrostatic current.

[0020] 3. This application achieves adaptive changes in the connection between the RF path and the ESD discharge path by coordinating the various coupling structures, thereby balancing RF signal transmission performance and electrostatic discharge capability within the same circuit structure, reducing the mutual constraints between the two and improving the overall performance of the circuit. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic flowchart of an embodiment of the ESD co-integration method for GaAs radio frequency integrated circuits provided in this application; Figure 2 This is a schematic diagram of the circuit principle corresponding to the GaAs radio frequency integrated circuit involved in this application; Figure 3 This is a schematic diagram illustrating the circuit connection principle of the GaAs radio frequency integrated circuit involved in this application; Figure 4 This is a schematic diagram of the vertical layered cross-section of the GaAs radio frequency integrated circuit involved in this application; Figure 5 This is a schematic diagram of the planar layout of the coupling interface unit according to an embodiment of the present invention; Figure 6 This is a schematic flowchart of an embodiment of step S105 in the ESD co-integration method for GaAs radio frequency integrated circuits provided in this application; Figure 7 This is a schematic flowchart of an embodiment of step S106 in the ESD co-integration method for GaAs radio frequency integrated circuits provided in this application. Detailed Implementation

[0023] The ESD co-integration method for GaAs RF integrated circuits described in this application is applicable to various RF integrated circuit design scenarios with high requirements for RF signal transmission performance and electrostatic protection capabilities, and is especially applicable to RF front-end circuits operating in the mid-high frequency and high frequency bands.

[0024] In practical applications, the method can be applied to circuit structures including, but not limited to, radio frequency power amplifiers (PA), low noise amplifiers (LNA), radio frequency switching circuits, and radio frequency transceiver front-end modules. In the above circuits, the radio frequency port is generally directly connected to an external antenna or test interface, which needs to ensure effective transmission of radio frequency signals and also has a certain degree of electrostatic discharge protection capability.

[0025] For example, at the input or output of an RF power amplifier, the RF port needs to maintain good impedance matching characteristics under high power or high frequency conditions, while it may be subject to electrostatic discharge (ESD) shocks during production testing or actual use. At the input of a low-noise amplifier, weak signals are more sensitive to changes in electrical characteristics, and the impact of additional structures is more stringent. In such application scenarios, integrating ESD protection structures using the method described in this application is beneficial for balancing RF performance and ESD protection requirements within the same circuit structure.

[0026] Furthermore, the method can also be applied to multi-stage RF cascaded circuits or highly integrated RF front-end chips. In such systems, the signal paths between different functional modules are complex, requiring high port consistency and overall stability. By employing the method described in this application, the relationship between RF paths and ESD discharge paths can be considered uniformly in the overall circuit design, thereby improving system-level reliability.

[0027] Furthermore, the method can also be applied to the design of radio frequency chips in application scenarios including but not limited to mobile communication terminals, wireless communication modules, radar systems and satellite communication equipment, in order to meet their comprehensive requirements for performance and reliability in complex electromagnetic environments.

[0028] This application first provides an embodiment of an ESD co-integration method for GaAs radio frequency integrated circuits. The method is applied to GaAs radio frequency integrated circuits. Please refer to [link to relevant documentation]. Figures 2 to 5The GaAs RF integrated circuit includes an RF port, an RF path electrically connected to the RF port, an ESD discharge unit, and a reference potential node. A coupling interface unit that does not form a DC conduction path is provided between the RF path and the ESD discharge unit. The coupling interface unit includes a frequency-selective coupling structure, a nonlinear coupling structure, and a capacitively coupled triggering structure.

[0029] To more clearly illustrate the solution of this application, the following is a brief description of the contents of several key structural drawings shown in this application: Figure 2 This is a schematic diagram of the circuit principle corresponding to the GaAs RF integrated circuit involved in this application. The diagram includes an RF port, an RF path, a coupling interface unit, an ESD discharge unit, and a reference potential node. The frequency-selective coupling structure uses an LC resonant unit composed of two-stage series inductors L1 and L2 and grounding capacitors C1 and C2 to present a high-impedance state in the RF operating frequency band and a low-impedance state under electrostatic discharge conditions, thereby realizing the impedance differential control of RF signals and electrostatic signals. The capacitor coupling trigger structure is composed of two sets of parallel planar coupling capacitors. The first electrode is connected to the RF path, and the second electrode is connected to the control terminal of the ESD discharge unit and the nonlinear coupling structure. The nonlinear coupling structure uses a graded conduction architecture composed of two sets of anti-parallel diode stacks to present a high-impedance isolation state in the low-voltage RF operating range and a low-impedance state through step-by-step conduction in the high-voltage electrostatic discharge range.

[0030] Figure 4 This is a schematic diagram of the vertical layered cross-section of the GaAs RF integrated circuit involved in this application. The diagram shows the structural layout of the TM2 layer, TM1 layer, M2 layer, M1 layer and GaAs substrate from top to bottom along the vertical stacking direction of the GaAs process: The TM2 layer is provided with the first electrode C1 (upper electrode) of the RF path and the capacitively coupled trigger structure (CCTS), which are integrally connected. It forms a non-DC-conducting capacitive coupling with the second electrode (lower electrode) of the CCTS of the TM1 layer below through the vertical interlayer dielectric; The second electrode of the CCTS of the TM1 layer is connected to the M2 layer through a vertical via; The M2 layer is provided with the upper electrode of the diode stack of the frequency selective coupling structure (FSCS, which forms a projected overlapping coupling region with the CCTS of the TM1 layer) and the nonlinear coupling structure (NLCS), which are connected in series through a vertical via; The upper electrode of the NLCS of the M2 layer is connected to the lower electrode of the NLCS diode stack of the M1 layer through a vertical via, and then connected in series with the ESD discharge unit, and finally connected to the reference potential node; The reference potential node is electrically connected to the GaAs substrate through a vertical via.

[0031] Figure 5This is a schematic diagram of the planar layout of the coupling interface unit according to an embodiment of the present invention. The diagram shows the functional partitions and overall connection relationship of the coupling interface unit: the radio frequency path, as the main signal link, is located at the top layer. The coupling interface unit below is divided into three functional areas: a trigger area, an impedance control area, and a current conduction area, which correspond to the capacitive coupling trigger structure, the frequency selective coupling structure, and the nonlinear coupling structure, respectively. The lower part of each area is connected to the vertical via array.

[0032] In this embodiment, the GaAs radio frequency integrated circuit is formed on a semiconductor substrate based on gallium arsenide process. Its overall structure includes a radio frequency port, a radio frequency path, an ESD discharge unit, a reference potential node, and a coupling interface unit disposed between the radio frequency path and the ESD discharge unit.

[0033] The radio frequency (RF) port, serving as an input or output interface for external RF signals, is located in the boundary region of the GaAs RF circuit and is electrically connected to the RF path via a metal interconnect structure. The RF path enables the transmission of RF signals between the RF port and internal functional units of the circuit. It may include microstrip line structures or other conductor structures suitable for high-frequency signal transmission and extends along a predetermined direction in the circuit layout.

[0034] The ESD discharge unit provides a current discharge path when an electrostatic discharge (ESD) event occurs. One end of the unit is associated with the radio frequency (RF) path, and the other end is electrically connected to the reference potential node to guide the electrostatic current to the reference potential node in the on-state. The reference potential node can be a grounded metal plane or other stable potential node, typically located on the back of the underlying metal structure or substrate of the circuit.

[0035] A coupling interface unit is provided between the radio frequency path and the ESD discharge unit. The coupling interface unit does not form a DC conduction path between the radio frequency path and the ESD discharge unit as a whole, but establishes an indirect connection between the two through various coupling structures.

[0036] Specifically, the frequency-selective coupling structure can be disposed between the radio frequency path and the reference potential node or in its vicinity to provide differentiated equivalent impedance characteristics under different frequency conditions. It can be composed of a combination of inductor and capacitor units and connected to other structures through a metal interconnect structure.

[0037] The capacitively coupled triggering structure can be set between the RF path and the control terminal of the ESD discharge unit, forming a capacitive coupling relationship through dielectric isolation, so that an electrical signal coupling channel is established between the RF path and the ESD discharge unit without forming a DC conduction. The nonlinear coupling structure is disposed in the conduction path or control path of the ESD discharge unit to exhibit different conduction characteristics under different voltage conditions. It may include a semiconductor device structure with voltage-dependent conduction behavior and forms an electrical connection with the capacitively coupled trigger structure and the frequency-selective coupling structure.

[0038] The coupling interface unit can be located in the vicinity of the radio frequency path and can be distributed between different metal layers based on a multilayer metal structure using GaAs technology. The interlayer connection between each structure is achieved through a vertical via array, thereby forming an indirect coupling structure system between the radio frequency path and the ESD discharge unit in three-dimensional space.

[0039] In an optional embodiment, the frequency-selective coupling structure and the capacitive coupling trigger structure in the coupling interface unit are respectively disposed in different metal layers, and at least a portion of the nonlinear coupling structure is disposed across adjacent metal layers and electrically connected through a vertical via array; the capacitive coupling trigger structure is disposed opposite to the radio frequency path in the vertical direction; the frequency-selective coupling structure is located in a non-co-layer metal structure of the radio frequency path and forms electromagnetic coupling with the radio frequency path; the nonlinear coupling structure is located in the interlayer connection path between the frequency-selective coupling structure and the reference potential node.

[0040] Specifically, the frequency-selective coupling structure and the capacitive coupling trigger structure are respectively disposed in different metal layers. The capacitive coupling trigger structure is disposed opposite to the radio frequency path in the vertical direction, so that the two form a capacitive coupling relationship through the interlayer medium. The frequency-selective coupling structure is disposed in a metal layer different from the radio frequency path, and forms an electromagnetic coupling relationship with the radio frequency path in space.

[0041] Furthermore, at least a portion of the nonlinear coupling structure is disposed across adjacent metal layers and interlayer electrical connection is achieved through a vertical via array, so that the nonlinear coupling structure is embedded in the coupling interface unit along the thickness direction.

[0042] Preferably, the nonlinear coupling structure is located in the interlayer connection path between the frequency-selective coupling structure and the reference potential node, thereby placing it on the critical path for electrostatic current transmission from the coupling region to the reference potential node.

[0043] In this embodiment, the capacitively coupled triggering structure, the frequency-selective coupling structure, and the nonlinear coupling structure are arranged in a three-dimensional space to form a structural system that is distributed at different levels and coupled to each other. The triggering effect is mainly realized along the vertical coupling direction, the impedance regulation effect is mainly carried out along the planar coupling direction, and the current conduction path is established layer by layer along the thickness direction, thereby constructing a three-dimensional coupling structure with directional division of labor as a whole.

[0044] In a further embodiment, The spatial arrangement of the coupling interface units satisfies the following relationship: The capacitively coupled triggering structure at least partially covers the frequency-selective coupling structure on the planar projection and forms an overlapping coupling region in the vertical direction; the nonlinear coupling structure is disposed on the current transmission path corresponding to the overlapping coupling region, so that the overlapping coupling region simultaneously constitutes the triggering area and the conduction control area; a preset distance is maintained between the radio frequency path and the overlapping coupling region.

[0045] In this embodiment, the capacitively coupled trigger structure at least partially covers the frequency-selective coupling structure on the planar projection and overlaps with it in the vertical direction, forming a coupling overlap region in space. This overlap allows the capacitively coupled trigger structure and the frequency-selective coupling structure to correspond to different coupling effects within the same region.

[0046] Furthermore, the nonlinear coupling structure is disposed on the current transmission path corresponding to the overlapping coupling region, so that when the electrostatic current passes through the region, it is simultaneously subjected to the combined action of the frequency-selective coupling structure and the nonlinear coupling structure, thereby enabling the overlapping coupling region to structurally undertake both trigger response and conduction control functions.

[0047] In one possible implementation, a preset distance is maintained between the RF path and the overlapping coupling region to limit the direct loading effect of the overlapping coupling region on the RF path while ensuring the capacitive coupling triggering effect. The preset distance can be set according to the parasitic tolerance of the RF path.

[0048] In an optional embodiment, the capacitively coupled trigger structure includes at least one pair of opposing first and second electrodes, the first electrode being connected to the radio frequency path and the second electrode being connected to the control terminal of the ESD discharge unit; at least a portion of the edges of the first and second electrodes are arranged parallel to the conductor boundary of the radio frequency path.

[0049] In this optional embodiment, the capacitively coupled trigger structure includes at least one pair of opposing first and second electrodes. The first electrode is electrically connected to the radio frequency path, and the second electrode is electrically connected to the control terminal of the ESD discharge unit, thereby forming a capacitive coupling relationship between them through a dielectric layer. The first and second electrodes can be positioned opposite each other on a planar projection and overlap at least in a local area to improve coupling stability.

[0050] Furthermore, at least a portion of the edges of the first electrode and the second electrode are arranged parallel to the conductor boundary of the radio frequency path, such that the capacitively coupled trigger structure forms a directional coupling relationship in the extension direction of the radio frequency path. This parallel arrangement ensures that the capacitive coupling has a relatively uniform distribution along the length of the radio frequency path.

[0051] In one specific implementation, the first electrode can be extended along the edge direction of the radio frequency path, and the second electrode is correspondingly disposed thereto, so that a coupling region is formed between the two along the extension direction of the radio frequency path, thereby reducing the impact of local concentrated coupling on the radio frequency path while ensuring the coupling strength.

[0052] In this embodiment, the method includes: S101. Determine the center frequency based on the operating frequency band of the radio frequency path, and calibrate the parasitic tolerance and ESD discharge capability. In this embodiment, the operating frequency band range corresponding to the RF path is first determined based on the design specifications or application requirements of the GaAs RF integrated circuit, and the center frequency of the frequency band is extracted from it.

[0053] Specifically, the center frequency can be determined based on the target operating frequency band of the RF circuit (e.g., a specific communication frequency band or a preset frequency range), using the midpoint of the band or a weighted method, as a reference for subsequent structural parameter configuration. The electrical characteristics of the RF path near the center frequency are evaluated to determine its tolerance range for additional parasitic parameters. This parasitic tolerance can be obtained by analyzing the impedance matching state or signal transmission characteristic variation trend of the RF path, for example, by determining the acceptable range of electrical characteristic changes after introducing additional structures through simulation or empirical parameters. Simultaneously, based on preset ESD protection level requirements (e.g., protection standards corresponding to different application scenarios), the electrostatic discharge capability range that the ESD discharge unit needs to withstand is determined, thereby obtaining the corresponding discharge capability requirements.

[0054] Specifically, one embodiment of this step includes: extracting the corresponding center frequency and frequency band range based on the target operating frequency band of the radio frequency path; within the frequency band range, analyzing the impedance matching characteristics of the radio frequency path according to equivalent parasitic parameters, and determining the allowable upper limit range of parasitic loading; determining the target discharge current range under electrostatic discharge conditions based on a preset ESD protection level; analyzing the equivalent path impedance of the current transmission path from the radio frequency path to the reference potential node, and determining the impedance constraint conditions that satisfy the target discharge current range; and determining the parameter constraint range for configuring the coupling interface unit based on the upper limit range of parasitic loading and the impedance constraint conditions.

[0055] Based on the target operating frequency band of the RF path, the corresponding center frequency and frequency band range are extracted. Specifically, the lower and upper frequency limits can be determined according to the design operating bandwidth of the RF circuit, and the center frequency can be selected accordingly. The center frequency can be taken as the median of the frequency band or determined by weighting based on the target application.

[0056] Within the specified frequency band, the electrical characteristics of the RF path are evaluated with the introduction of additional structures. Specifically, the influence of the coupling interface unit on the RF path is equated to additional parasitic parameters, and the changes in its matching characteristics are analyzed in conjunction with the original impedance matching state of the RF path. By comparing the changes in reflection or transmission characteristics before and after the introduction of parasitic parameters, the upper limit of the allowable parasitic loading is determined while ensuring that the RF performance basically meets the design requirements.

[0057] Based on a preset ESD protection level, the target discharge current range required under electrostatic discharge (ESD) conditions is determined. The target discharge current can be determined based on the typical peak current or equivalent stress conditions under the corresponding protection level. The equivalent impedance of the path is evaluated by considering the actual current transmission path from the RF path to the reference potential node. Specifically, the current transmission path can be considered as an equivalent network composed of multiple series or parallel resistors, inductors, and conducting units. Based on the target discharge current range, the equivalent impedance constraints that the path must satisfy in the conducting state are determined.

[0058] Based on the parasitic loading upper limit and the equivalent impedance constraint, the coupling interface unit is comprehensively constrained to determine its parameter configuration range. The parameter configuration range can be represented by the value range of each related structure in terms of geometric dimensions, relative spacing, or connection method, ensuring that the influence of the coupling interface unit on the RF path under RF operating conditions does not exceed the parasitic loading upper limit, while simultaneously meeting the impedance constraint requirements of the discharge path under electrostatic discharge conditions.

[0059] S102. Configure the parameters of the frequency-selective coupling structure so that it corresponds to different impedance states under the operating frequency band and electrostatic shock conditions. In this embodiment, the frequency-selective coupling structure is used to exhibit differentiated equivalent impedance characteristics under different frequency conditions. Specifically, the equivalent inductance and capacitance parameters in the frequency-selective coupling structure can be configured according to the center frequency to make it exhibit a higher equivalent impedance near the center frequency, thereby reducing its impact on the radio frequency signal path. Under low-frequency or transient conditions (corresponding to the spectral range of electrostatic discharge), the frequency-selective coupling structure is made to exhibit a relatively low equivalent impedance to facilitate current transmission towards the reference potential node.

[0060] In practice, the parameter configuration can be achieved by adjusting the geometric dimensions, relative positions, or connection methods of the relevant conductor structures, thereby enabling the frequency-selective coupling structure to have different electrical performances under different operating conditions.

[0061] In this embodiment, the parameter constraint range includes at least: Parasitic coupling parameter constraints used to limit the radio frequency path; Path impedance parameter constraints used to meet electrostatic discharge capability; Trigger parameter constraints used to control ESD triggering behavior; The parasitic coupling parameter constraints, path impedance parameter constraints, and trigger parameter constraints are interrelated, so that the coupling interface unit exhibits different conduction characteristics in the radio frequency operating state and the electrostatic shock state, respectively.

[0062] In this application, the parameter constraint range is used to limit the parasitic coupling parameter constraints of the radio frequency path. The parasitic coupling parameter constraints are used to limit the additional electrical effects introduced by the coupling interface unit on the radio frequency path within the radio frequency operating band, which can be reflected as the upper limit range of the equivalent parasitic capacitance or parasitic coupling strength, thereby keeping the impedance matching state of the radio frequency path within a preset allowable range.

[0063] The parameter constraint range is also used to satisfy the path impedance parameter constraint of electrostatic discharge capability. The path impedance parameter constraint is used to limit the equivalent impedance range of the current transmission path from the RF port to the reference potential node under electrostatic shock conditions, so as to ensure that the current transmission path has sufficient conduction capability under the target discharge current condition.

[0064] The parameter constraint range is also used to control the triggering parameter constraints of ESD triggering behavior. The triggering parameter constraints are used to limit the range of triggering conditions corresponding to the ESD discharge unit entering the conduction state, so that it remains in a non-conducting state within the normal radio frequency operating voltage range, but can be effectively triggered under electrostatic discharge conditions.

[0065] Furthermore, the parasitic coupling parameter constraints, path impedance parameter constraints, and triggering parameter constraints are not independent of each other, but rather form a coupling relationship under the structural configuration of the same coupling interface unit. Specifically, the restriction on the parasitic coupling parameter affects the coupling strength of the capacitively coupled triggering structure, thereby affecting the triggering parameter; the constraint on the path impedance is related to the conduction capability of the frequency-selective coupling structure and the nonlinear coupling structure; and the setting of the triggering parameter, in turn, affects the conduction state of the path under different voltage conditions.

[0066] By coordinating the setting of the above-mentioned parameter constraints, the coupling interface unit exhibits high-resistance isolation characteristics in the radio frequency operating state and low-resistance conduction characteristics under electrostatic shock conditions, thereby realizing differentiated electrical behavior under different operating states.

[0067] S103. Configure the parameters of the capacitive coupling trigger structure to form a capacitive coupling with the RF port and connect it to the control terminal of the ESD discharge unit. In this embodiment, the capacitively coupled trigger structure is used to establish a non-DC-conducting electrical signal coupling path between the RF port and the ESD discharge unit. Specifically, by placing a coupling electrode near the RF path or RF port, and placing another coupling electrode corresponding to the control terminal of the ESD discharge unit, a capacitive coupling relationship is formed between the two through dielectric isolation. By configuring the area, spacing, and relative position of the coupling electrodes, the influence of the capacitive coupling structure on the signal path under RF operating conditions is kept within an acceptable range, while simultaneously generating an effective electrical signal response at the control terminal of the ESD discharge unit under rapid voltage changes. In a specific implementation, the coupling electrodes can be disposed in the same metal layer or different metal layers, and the capacitive coupling relationship is achieved through layout arrangement.

[0068] S104. Configure the parameters of the nonlinear coupling structure so that it is in a high-resistance state in the first voltage range and in a low-resistance state in the second voltage range. In this embodiment, the nonlinear coupling structure is used to adjust the conduction characteristics between the RF path and the ESD discharge unit under different voltage conditions. By selecting semiconductor devices or structures with voltage-dependent conduction characteristics and configuring their connection methods and related parameters, they are kept in a high-impedance state within the normal operating voltage range, thereby avoiding significant impact on the RF signal path; while when the voltage range exceeds a preset range, the nonlinear coupling structure enters a conducting state, reducing the equivalent impedance. In implementation, the conduction characteristics can be made to meet the above requirements by adjusting the size, connection method, or bias conditions of the relevant devices.

[0069] Specifically, step S104 may include constructing the nonlinear coupling structure as a hierarchical conduction structure formed by multiple nonlinear units connected in series and / or in parallel, with each nonlinear unit corresponding to a different conduction threshold; adjusting the connection order and parameter combination of the multiple nonlinear units so that the hierarchical conduction structure exhibits a high-resistance state in the first voltage range and gradually enters the conduction state in the second voltage range.

[0070] In this embodiment, the nonlinear coupling structure is constructed as a hierarchical conduction structure formed by a series and / or parallel combination of multiple nonlinear units. Each nonlinear unit corresponds to a different conduction threshold, forming a conduction path with multi-level response characteristics as a whole. Specifically, the multiple nonlinear units can be arranged along the current transmission direction from the radio frequency path to the reference potential node, so that the hierarchical conduction structure spatially corresponds to the current transmission path. By configuring the connection order and related parameters of the multiple nonlinear units, the conduction thresholds of each nonlinear unit are distributed. The parameters may include structural dimensions or connection methods related to the conduction characteristics of the nonlinear units, so that each nonlinear unit sequentially enters the conduction state at different voltage levels.

[0071] Therefore, within the first voltage range, none of the nonlinear units have reached their conduction conditions, and the hierarchical conduction structure exhibits a high resistance state as a whole; while within the second voltage range, as the voltage level increases, the nonlinear units with different thresholds conduct in sequence, causing the hierarchical conduction structure to gradually reduce its equivalent impedance and ultimately form a conduction path that meets the requirements for electrostatic discharge.

[0072] S105. An indirect connection is established between the radio frequency path and the ESD discharge unit through the coupling interface unit, so that the ESD discharge unit is isolated from the radio frequency path in the radio frequency working state. In this embodiment, a non-directly conductive connection is formed between the RF path and the ESD discharge unit through the combination of the frequency-selective coupling structure, the capacitive coupling trigger structure, and the non-linear coupling structure. Specifically, in RF operation, because the frequency-selective coupling structure exhibits high impedance and the non-linear coupling structure is in a high-impedance state, the ESD discharge unit is electrically isolated from the RF path, thereby reducing the impact on RF signal transmission.

[0073] In an optional embodiment, step S105 may include the following implementation: S1051. Connect the capacitively coupled trigger structure to the control terminal of the ESD discharge unit, so that the capacitively coupled trigger structure and the radio frequency path are arranged in a non-overlapping manner in space. In this embodiment, in terms of spatial layout, the capacitively coupled trigger structure is connected to the control terminal of the ESD discharge unit, and the capacitively coupled trigger structure is arranged in a non-overlapping manner relative to the RF path. Specifically, the capacitively coupled trigger structure and the RF path are capacitively coupled through dielectric isolation, and the two do not directly overlap in planar projection, thereby avoiding direct conduction or strong loading effects on the RF path.

[0074] S1052. The frequency selective coupling structure is disposed between the radio frequency path and the reference potential node, and is disposed in layers with the capacitive coupling trigger structure. The frequency-selective coupling structure is positioned between the radio frequency path and the reference potential node, and is arranged vertically in layers with the capacitively coupled trigger structure. This allows the frequency-selective coupling structure to primarily function on the impedance control path between the radio frequency path and the reference potential node, while the capacitively coupled trigger structure primarily functions on the control path, thus achieving spatial separation of different functions.

[0075] S1053. Connect the nonlinear coupling structure in series in the main current path of the ESD discharge unit, and position it between the frequency selective coupling structure and the reference potential node; The nonlinear coupling structure is connected in series in the main current path of the ESD discharge unit and positioned between the frequency-selective coupling structure and the reference potential node, placing it downstream of the electrostatic current transmission path. This arrangement allows the nonlinear coupling structure to perform voltage control and conduction regulation in the current conduction path.

[0076] S1054. The capacitively coupled triggering structure, the frequency-selective coupling structure, and the nonlinear coupling structure are arranged in a spatial layout corresponding to the triggering region, the impedance control region, and the current conduction region, respectively.

[0077] Based on the structure provided in this embodiment, the capacitively coupled trigger structure, the frequency-selective coupling structure, and the nonlinear coupling structure are spatially positioned to correspond to the trigger region, the impedance control region, and the current conduction region, respectively, and are sequentially distributed along the direction from the radio frequency path to the reference potential node, thereby forming a coupling interface structure with clearly defined functional partitions as a whole.

[0078] S106. Under electrostatic discharge conditions, the ESD discharge unit is turned on and a discharge path is formed through the reference potential node.

[0079] In this embodiment, when an electrostatic discharge (ESD) event occurs at the RF port, the voltage on the RF path changes rapidly. This triggers a response signal at the control terminal of the ESD discharge unit via the capacitive coupling structure. Under the influence of this response signal, and considering the conduction characteristics of the nonlinear coupling structure, the ESD discharge unit enters a conducting state, thereby establishing a current path between the RF port and the reference potential node. Simultaneously, with the participation of the frequency-selective coupling structure, the equivalent impedance of the current path meets the requirements for ESD current release, allowing the ESD current to be guided to the reference potential node, thus protecting the RF circuit.

[0080] In an optional embodiment, this application provides a specific implementation of step S106 as follows: S1061. When the ESD discharge unit is turned on, a main current transmission path is established between the radio frequency path and the reference potential node through the nonlinear coupling structure. When the ESD discharge unit is triggered to conduct, a main current transmission path is established between the radio frequency path and the reference potential node through the nonlinear coupling structure. The main current transmission path extends along the interior of the coupling interface unit and corresponds to the conduction state of the nonlinear coupling structure.

[0081] S1062. The equivalent impedance of the main current transmission path is adjusted by the frequency selective coupling structure so that the main current transmission path meets the impedance constraint condition under electrostatic shock conditions. The equivalent impedance of the main current transmission path is adjusted by the frequency-selective coupling structure so that the main current transmission path meets the impedance constraint condition under electrostatic shock conditions, thereby ensuring the transmission capability of electrostatic current in the path.

[0082] S1063. The main current transmission path is connected to the reference potential node through a vertical via array, wherein the vertical via array is distributed along the boundary region of the coupling interface unit to form a surrounding current discharge channel around the coupling interface unit, and the vertical via array is discretely distributed in the circumferential direction of the coupling interface unit. By setting up a vertical via array, a three-dimensional conductive connection is established between the main current transmission path and the reference potential node. Specifically, the vertical via array is arranged along the boundary region of the coupling interface unit, forming a surrounding distribution in the planar direction around the coupling interface unit, so that the main current transmission path achieves current diversion through multiple distributed channels before entering the reference potential node.

[0083] S1064. The main current transmission path is connected to the reference potential node through a vertical via array to form a current discharge channel along the thickness direction. The connection area between the main current transmission path and the radio frequency path is defined within the coupling interface unit.

[0084] Each of the vertical vias penetrates different metal layers along the thickness direction, creating multiple connections in the vertical direction for the main current transmission path, thereby constructing a three-dimensional current discharge channel composed of planar distribution and vertical conduction. Preferably, the electrical connection region between the main current transmission path and the RF path is confined within the coupling interface unit, thereby concentrating the injection and release of electrostatic current within the coupling interface unit region and reducing the impact on other areas of the RF path.

[0085] In this embodiment, the electrostatic current is no longer concentrated and released through a single path when it is in the conducting state. Instead, it is dispersed in space through the surrounding vertical via array, thereby improving the overall discharge capacity and reducing the local current density.

[0086] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between apparatuses or units through some interfaces, and may be electrical, mechanical, or other forms.

[0087] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0088] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0089] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. An ESD co-integration method for GaAs radio frequency integrated circuits, characterized in that, The method is applied to GaAs radio frequency integrated circuits, which include a radio frequency port, a radio frequency path electrically connected to the radio frequency port, an ESD discharge unit, and a reference potential node. A coupling interface unit that does not constitute a DC conduction path is provided between the radio frequency path and the ESD discharge unit. The coupling interface unit includes a frequency-selective coupling structure, a nonlinear coupling structure, and a capacitive coupling trigger structure. The method includes: The center frequency is determined based on the operating frequency band of the radio frequency path, and the parasitic tolerance and ESD discharge capability are calibrated. Configure the parameters of the frequency-selective coupling structure so that it corresponds to different impedance states under the operating frequency band and electrostatic shock conditions; Configure the parameters of the capacitive coupling trigger structure to form a capacitive coupling with the RF port and connect it to the control terminal of the ESD discharge unit; The parameters of the nonlinear coupling structure are configured such that it is in a high-resistance state in the first voltage range and in a low-resistance state in the second voltage range. The coupling interface unit establishes an indirect connection between the radio frequency path and the ESD discharge unit, thereby isolating the ESD discharge unit from the radio frequency path during radio frequency operation. Under electrostatic discharge conditions, the ESD discharge unit is turned on, and a discharge path is formed through the reference potential node.

2. The ESD co-integration method for GaAs radio frequency integrated circuits according to claim 1, characterized in that, The process of determining the center frequency based on the operating frequency band of the radio frequency path and calibrating the parasitic tolerance and ESD discharge capability includes: Based on the target operating frequency band of the radio frequency path, the corresponding center frequency and frequency band range are extracted. Within the specified frequency band, the impedance matching characteristics of the radio frequency path are analyzed based on the equivalent parasitic parameters, and the upper limit of the allowable parasitic loading range is determined. Based on the preset ESD protection level, the target discharge current range under electrostatic shock conditions is determined. Based on the current transmission path from the radio frequency path to the reference potential node, the equivalent path impedance of the current transmission path is analyzed to determine the impedance constraint conditions that satisfy the target discharge current range. Based on the parasitic loading upper limit range and the impedance constraint condition, the parameter constraint range for configuring the coupling interface unit is determined.

3. The ESD co-integration method for GaAs radio frequency integrated circuits according to claim 2, characterized in that, The parameter constraint range includes at least: Parasitic coupling parameter constraints used to limit the radio frequency path; Path impedance parameter constraints used to meet electrostatic discharge capability; Trigger parameter constraints used to control ESD triggering behavior; The parasitic coupling parameter constraints, path impedance parameter constraints, and trigger parameter constraints are interrelated, so that the coupling interface unit exhibits different conduction characteristics in the radio frequency operating state and the electrostatic shock state, respectively.

4. The ESD co-integration method for GaAs radio frequency integrated circuits according to claim 1, characterized in that, The step of establishing an indirect connection between the RF path and the ESD discharge unit through the coupling interface unit, thereby isolating the ESD discharge unit from the RF path during RF operation, includes: The capacitively coupled trigger structure is connected to the control terminal of the ESD discharge unit, so that the capacitively coupled trigger structure is arranged in a non-overlapping manner with the radio frequency path in space. The frequency selective coupling structure is disposed between the radio frequency path and the reference potential node, and is disposed in layers with the capacitive coupling trigger structure; The nonlinear coupling structure is connected in series in the main current path of the ESD discharge unit and is located between the frequency selective coupling structure and the reference potential node; The capacitively coupled triggering structure, the frequency-selective coupling structure, and the nonlinear coupling structure are arranged in a spatial layout corresponding to the triggering region, the impedance-controlled region, and the current-conducting region, respectively.

5. The ESD co-integration method for GaAs radio frequency integrated circuits according to claim 1, characterized in that, The step of activating the ESD discharge unit under electrostatic discharge conditions and forming a discharge path through the reference potential node includes: When the ESD discharge unit is turned on, a main current transmission path is established between the radio frequency path and the reference potential node through the nonlinear coupling structure. The equivalent impedance of the main current transmission path is adjusted by the frequency-selective coupling structure so that the main current transmission path meets the impedance constraint condition under electrostatic shock conditions. The main current transmission path is connected to the reference potential node by a vertical via array, wherein the vertical via array is distributed along the boundary region of the coupling interface unit to form a surrounding current discharge channel around the coupling interface unit, and the vertical via array is discretely distributed in the circumferential direction of the coupling interface unit. The main current transmission path is connected to the reference potential node by a vertical via array, forming a current discharge channel along the thickness direction. The connection area between the main current transmission path and the radio frequency path is defined within the coupling interface unit.

6. The ESD co-integration method for GaAs radio frequency integrated circuits according to claim 1, characterized in that, The parameters configured for the frequency-selective coupling structure are such that they correspond to different impedance states under the operating frequency band and electrostatic discharge (ESD) conditions, including: The frequency-selective coupling structure is configured as at least two resonant units distributed along the radio frequency path, each resonant unit corresponding to different equivalent inductance and capacitance parameters; The resonant units are arranged at spatial intervals and indirectly coupled through the radio frequency path; By adjusting the parameter combination of the resonant unit, the frequency-selective coupling structure can exhibit high impedance characteristics within the operating frequency band. By adjusting the connection relationship of the resonant unit, the frequency-selective coupling structure forms an equivalent low-impedance path in the low-frequency range corresponding to electrostatic shock.

7. The ESD co-integration method for GaAs radio frequency integrated circuits according to claim 1, characterized in that, The parameters of the nonlinear coupling structure are configured such that it is in a high-resistance state in a first voltage range and a low-resistance state in a second voltage range, including: The nonlinear coupling structure is constructed as a hierarchical conduction structure formed by multiple nonlinear units connected in series and / or in parallel, with each nonlinear unit corresponding to a different conduction threshold. The connection order and parameter combination of the multiple nonlinear units are adjusted so that the graded conduction structure exhibits a high-resistance state in the first voltage range and enters the conduction state step by step in the second voltage range.

8. The ESD co-integration method for GaAs radio frequency integrated circuits according to claim 1, characterized in that, The frequency-selective coupling structure and the capacitive coupling trigger structure in the coupling interface unit are respectively disposed in different metal layers, and at least a portion of the nonlinear coupling structure is disposed across adjacent metal layers and electrically connected through a vertical via array; the capacitive coupling trigger structure is disposed opposite to the radio frequency path in the vertical direction; the frequency-selective coupling structure is located in the non-same-layer metal structure of the radio frequency path and forms electromagnetic coupling with the radio frequency path; the nonlinear coupling structure is located in the interlayer connection path between the frequency-selective coupling structure and the reference potential node.

9. The ESD co-integration method for GaAs radio frequency integrated circuits according to claim 8, characterized in that, The spatial arrangement of the coupling interface units satisfies the following relationship: The capacitively coupled triggering structure at least partially covers the frequency-selective coupling structure on the planar projection and forms an overlapping coupling region in the vertical direction; the nonlinear coupling structure is disposed on the current transmission path corresponding to the overlapping coupling region, so that the overlapping coupling region simultaneously constitutes the triggering area and the conduction control area; a preset distance is maintained between the radio frequency path and the overlapping coupling region.

10. The ESD co-integration method for GaAs radio frequency integrated circuits according to claim 1, characterized in that, The capacitively coupled trigger structure includes at least one pair of oppositely arranged first and second electrodes. The first electrode is connected to the radio frequency path, and the second electrode is connected to the control terminal of the ESD discharge unit. At least a portion of the edges of the first and second electrodes are arranged parallel to the conductor boundary of the radio frequency path.

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