An h-bridge power device based on bcd process

Abstract

The application relates to the technical field of H-bridge power devices, and provides an H-bridge power device based on a BCD process, which adopts a central symmetry layout on a semiconductor substrate and comprises parallel VDD and GND metal buses and an output metal port; the VDD and GND metal buses respectively extend a plurality of power metal strips which are parallel to each other and are alternately arranged towards the output port; each power metal strip has a width gradient structure and a round-corner transition edge corner which are continuous from the bus to the port direction; and the power metal strip is connected with an underlying power transistor active area through a contact hole array; the device is configured through specific shape and size, so that the metal path resistances from the VDD and the GND to the output end are equal, thereby realizing uniform distribution of current, reducing parasitic parameters, improving switching speed, and significantly improving the thermal reliability and overall reliability of the device.

Description

Technical Field

[0001] This application relates to the field of H-bridge power device technology, specifically to an H-bridge power device based on BCD technology. Background Technology

[0002] In power integrated circuit design, traditional H-bridge power transistors often employ a diagonal layout. This design results in slanted gate traces at the metal wiring layer, which not only lengthens the drive signal path but also introduces significant parasitic resistance and inductance, thereby affecting the integrity of the gate drive signal and switching performance. Simultaneously, the tapered narrowing design of the metal bus in the source / drain regions leads to excessively high local current density, making it highly susceptible to hot spots under high power conditions. This increases the risk of electromigration (EM) failure and severely limits the device's thermal stability and reliability.

[0003] like Figure 1 As shown, in a traditional diagonal structure, current converges obliquely from GND and VDD to OUT, resulting in significant asymmetry in the routing path. Because the metal wiring extends obliquely in space, the current at the far end needs to take a longer path to reach the output terminal, leading to uneven current carrying by different finger connectors. Utility Model Content

[0004] To help solve the above-mentioned technical problems, this application provides an H-bridge power device based on BCD technology, which adopts the following technical solution: An H-bridge power device based on BCD technology includes an H-bridge circuit formed on a semiconductor substrate, consisting of a first group of power transistors and a second group of power transistors, wherein the layout structure of the H-bridge circuit is centrally symmetrical on the semiconductor substrate. The layout structure includes a VDD metal bus and a GND metal bus arranged parallel to a first direction, and an output metal port arranged between the VDD metal bus and the GND metal bus in a second direction perpendicular to the first direction. The VDD metal bus extends toward the output metal port with multiple first power metal fingers, and the GND metal bus extends toward the output metal port with multiple second power metal fingers; The first power metal finger and the second power metal finger are arranged parallel to each other and alternately, and both point towards the output metal port; Each of the first power metal fingers and each of the second power metal fingers has a continuous width gradient structure in its extension direction from the bus to the output metal port, and the corners of all the power metal fingers are rounded transition structures. Each of the power metal fingers is connected to the active region of the corresponding power transistor through the contact hole array below it; The shape and size of the power metal fingers are configured such that the resistance path from the GND metal bus through the first power metal finger to the output metal port is equal to the resistance path from the VDD metal bus through the second power metal finger to the output metal port.

[0005] Preferably, each group of power transistors includes at least two NMOS transistors, and the rounded corner transition structure is a circular arc transition or an elliptical arc transition.

[0006] Preferably, the power metal fingers connecting to the VDD metal bus and the power metal fingers connecting to the GND metal bus are arranged alternately in the direction pointing to the output metal port.

[0007] Preferably, the power transistor employs a multi-finger gate structure, wherein the gate fingers are perpendicular to the extending direction of the power metal fingers.

[0008] Preferably, the width gradient structure is a linear gradient.

[0009] In summary, this application enables parallel finger insertion from both GND and VDD sides towards the center. This structure ensures that the total length of each metal path from its location to OUT is essentially the same, thereby improving the uniformity of current distribution. The longer external path has a more sufficient guiding distance, while the shorter internal path reduces crosstalk and congestion, achieving an optimized current path of "equal resistance, symmetrical current, and low hot spots." Simultaneously, the rounded corner transition reduces the concentration of electric field at sharp corners, enhances heat dissipation efficiency, and comprehensively improves the stability and reliability of the power transistor. Attached Figure Description

[0010] Figure 1 The accompanying drawings are for reference only; Figure 2 This is a schematic diagram of an H-bridge power device based on BCD technology according to this application; Figure 3 for Figure 2 The equivalent circuit diagram of the embodiment shown is illustrated.

[0011] Reference numerals: 1-Angled gate trace; 2-GND metal bus; 3-VDD metal bus; 4-Output metal port; 5-First power metal finger; 6-Second power metal finger. Detailed Implementation

[0012] The present application will be further described below with reference to the accompanying drawings. The structure and principle of the present application are very clear to those skilled in the art. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

[0013] Figure 2This is a schematic diagram of an H-bridge power device based on BCD technology according to this application. Figure 3 for Figure 2 The equivalent circuit diagram of the embodiment shown is illustrated.

[0014] The H-bridge power device based on BCD technology of this application includes an H-bridge circuit formed on a semiconductor substrate, consisting of a first group of power transistors and a second group of power transistors. The layout structure of the H-bridge circuit is centrally symmetrical on the semiconductor substrate.

[0015] The layout structure includes a VDD metal bus 3 and a GND metal bus 2 arranged parallel to each other along a first direction, and an output metal port 4 arranged between the VDD metal bus 3 and the GND metal bus 2 along a second direction perpendicular to the first direction; multiple first power metal bars 5 extend from the VDD metal bus 3 toward the output metal port 4, and multiple second power metal bars 6 extend from the GND metal bus 2 toward the output metal port 4.

[0016] The first power metal finger strip 5 and the second power metal finger strip 6 are arranged parallel to each other and alternately, and both point to the output metal port 4; each of the first power metal finger strip 5 and each of the second power metal finger strip 6 has a continuous width gradient structure in its extension direction from the bus to the output metal port 4, and the corners of all power metal finger strips are rounded transition structures.

[0017] Each power metal finger is connected to the active region of the corresponding power transistor through the contact hole array below it; the shape and size of the power metal finger are configured such that the resistance path from the GND metal bus 2 through the first power metal finger 5 to the output metal port 4 is equal to the resistance path from the VDD metal bus 3 through the second power metal finger 6 to the output metal port 4.

[0018] Combination Figure 2 and Figure 3It is understood that the H-bridge power device based on BCD technology in this application includes an H-bridge circuit composed of two sets of power transistors formed on a semiconductor substrate. An output metal port 4 is located between the two sets of power transistors, and the two sets of power transistors are symmetrically arranged on both sides of the output metal port 4. Multiple power metal fingers extend parallel to the output metal port 4 from the GND metal bus 2 and the VDD metal bus 3, respectively. The power metal fingers connecting the metal bus and the power metal fingers connecting the GND metal bus 2 are arranged parallel to each other and symmetrically point towards the output metal port 4 of the H-bridge. The power metal fingers have a gradually narrowing width in the direction of extension from the metal bus to the central output metal port 4, and all transitions are rounded. The length of the power metal fingers is set to be an equal resistance path from the GND metal bus 2 or the VDD metal bus 3 to the output metal port 4, so that the current carried by each finger is equal. A contact hole array is provided between the power metal fingers and the semiconductor substrate to reduce the contact resistance of the vias and disperse the current density.

[0019] It should be noted that the power metal fingers are divided into a "wide segment" near the bus and a "narrow segment" near the OUT in the current direction. The width W1 of the "wide segment" and the width W2 of the "narrow segment" of the same finger meet the following requirements: 'a' is a positive value greater than 1, and the transition between the "wide segment" and the "narrow segment" is achieved through continuous rounded corners. The total resistance of all power metal fingers is designed to be equal. Specifically, for long finger insertions located on the outer side of the chip (centered on the middle area of ​​GND metal bus 2 and VDD metal bus 3, with the side furthest from the center being the outer side), the ratio of the "narrow segment" length Ln to the "wide segment" length Lw is... b is a positive value less than 1. For the short finger insert located recessed inside the chip (the side closer to the center is the outer side), its... c is a positive value less than 1. This causes the metal resistor from the GND or VDD bus to OUT to... The same constant is used, where Rw and Rn are the unit length resistances of the "wide segment" and "narrow segment" respectively, and k is a process constant.

[0020] At the junction of the "wide segment" and the "narrow segment" and in the OUT convergence area, redundant via arrays are connected in parallel to reduce local resistance and disperse current density.

[0021] In the embodiments of this application, each group of power transistors includes at least two NMOS transistors, and the rounded corner transition structure is either a circular arc transition or an elliptical arc transition.

[0022] In this embodiment, the power metal fingers connecting the VDD metal bus 3 and the power metal fingers connecting the GND metal bus 2 are arranged alternately in the direction pointing to the output metal port 4.

[0023] In this embodiment, the power transistor employs a multi-finger gate structure, where the gate fingers are perpendicular to the extending direction of the power metal fingers. The width L of the finger insertion structure satisfies the following relationship: ,in Indicates the total current. The first metal layer is M1, the second metal layer is M2, the third metal layer is M3, and the fourth metal layer is M4. Let the current carrying capacity of M1, M2, M3, and M4 be... , , , mA / μm, number of fingers The flow capacity of the orifices corresponding to M1, M2, M3, and M4 are respectively , , , mA / each.

[0024] In this embodiment of the application, the number of vias in the layout structure satisfies the following relationship: cont represents the number of vias from the active region to the first metal layer. This indicates the number of vias connecting the first metal layer to the second metal layer. This indicates the number of vias corresponding to the transition from the second to the third metal layer. This indicates the number of vias corresponding to the transition from the third to the fourth metal layer. ; ; ; .

[0025] To make the inventive points of this application clearer, the differences between this application and the prior art are emphasized again: Optimized switching speed: Figure 1 The oblique gate trace 1 has a long and uneven distribution, which leads to an increase in gate parasitic resistance and inductance. In addition, the metal trace overlaps with the gate over a large area, resulting in a large gate-drain capacitance, which limits the switching speed.

[0026] Figure 2 The design employs a rounded finger insertion structure that is wider at the top and narrower at the bottom, optimizing path length and symmetry while preserving metal ductility. By rationally controlling the overlap area between the metal and the gate, gate resistance and gate-drain capacitance are effectively reduced, thereby improving switching response speed.

[0027] Figure 1The metal bus has a trapezoidal gradient, and manufacturing deviations can easily lead to asymmetrical distribution, affecting drive consistency and long-term stability.

[0028] Figure 2 The new structure, combined with multi-layer metal coverage, enhances the symmetry of metal connections and the consistency of drive paths, which helps to improve the electrical matching accuracy and thermal reliability of the device.

[0029] Current distribution optimization: Figure 1 Traditional ladder bus systems are prone to current concentration at the entrance end. Due to the narrowing of the metal and manufacturing imperfections at the end, the actual current distribution is uneven, resulting in local current accumulation.

[0030] Figure 2 The new structure achieves a natural gradient from wide to narrow in the current direction, which helps guide the current to be distributed evenly. Combined with rounded corners, it reduces the abrupt change points in current density, improves the local congestion effect, and enhances the overall current carrying capacity.

[0031] Thermal management performance optimization: Figure 1 Due to the uneven metal path and concentrated current density, hot spots are easily formed in local areas, resulting in large thermal gradients and affecting heat dissipation.

[0032] Figure 2 The new structure allows for a smoother current transition, which facilitates uniform heat dissipation in both vertical and horizontal directions. At the same time, the rounded corner design alleviates stress concentration, reduces local temperature rise, and significantly improves the chip's thermal management performance.

Claims

1. An H-bridge power device based on BCD technology, comprising an H-bridge circuit formed on a semiconductor substrate and consisting of a first group of power transistors and a second group of power transistors, characterized in that, The layout of the H-bridge circuit is centrally symmetrical on the semiconductor substrate; The layout structure includes a VDD metal bus and a GND metal bus arranged parallel to a first direction, and an output metal port arranged between the VDD metal bus and the GND metal bus in a second direction perpendicular to the first direction. The VDD metal bus extends toward the output metal port with multiple first power metal fingers, and the GND metal bus extends toward the output metal port with multiple second power metal fingers; The first power metal finger and the second power metal finger are arranged parallel to each other and alternately, and both point towards the output metal port; Each of the first power metal fingers and each of the second power metal fingers has a continuous width gradient structure in its extension direction from the bus to the output metal port, and the corners of all the power metal fingers are rounded transition structures. Each of the power metal fingers is connected to the active region of the corresponding power transistor through the contact hole array below it; The shape and size of the power metal fingers are configured such that the resistance path from the GND metal bus through the first power metal finger to the output metal port is equal to the resistance path from the VDD metal bus through the second power metal finger to the output metal port.

2. The H-bridge power device based on BCD technology according to claim 1, characterized in that, Each power transistor group includes at least two NMOS transistors, and the rounded corner transition structure is either a circular arc transition or an elliptical arc transition.

3. The H-bridge power device based on BCD technology according to claim 1, characterized in that, The power metal fingers connecting to the VDD metal bus and the power metal fingers connecting to the GND metal bus are arranged alternately in the direction pointing to the output metal port.

4. The H-bridge power device based on BCD technology according to claim 1, characterized in that, The power transistor employs a multi-finger gate structure, with its gate fingers perpendicular to the extension direction of the power metal fingers.

5. The H-bridge power device based on BCD technology according to claim 1, characterized in that, The width gradient structure is a linear gradient.

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