ESD protection device resistant to positive and negative high voltage, preparation method thereof and electronic equipment

Abstract

This invention relates to the field of semiconductor devices and provides an ESD protection device resistant to positive and negative high voltages, its fabrication method, and an electronic device. The ESD protection device includes: a substrate, a buried layer formed in the substrate, and an epitaxial layer formed on the substrate and the buried layer. A first high-voltage well with a ring structure and a second high-voltage well with a V-shaped structure are formed on the buried layer, and the second high-voltage well is formed inside the first high-voltage well. The doping concentration of the first high-voltage well and the first active region gradually decreases, and the doping concentration of the second high-voltage well and the second active region gradually decreases. Then, a third active region, a fourth active region, a fifth active region, a sixth active region, and a seventh active region are set inside and outside the first high-voltage well and in the hole structure of the second high-voltage well. By connecting the active regions or connecting resistors between the active regions, the device ports can be ensured to operate normally under positive and negative high voltages, and have the characteristics of low leakage current and no breakdown delay.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor devices, and particularly relates to an ESD protection device resistant to positive and negative high voltages, its preparation method, and electronic equipment. Background Technology

[0002] As semiconductor process dimensions shrink, the gap between device operating voltage and breakdown voltage becomes smaller, making electrostatic discharge (ESD) problems in integrated circuits increasingly significant. Typically, the operating voltage of an IC port is between 0V and the power supply voltage. Therefore, the ESD structure of a typical device port only needs to ensure that there is no leakage current when the port voltage is between 0V and the power supply voltage.

[0003] However, in practical applications, some existing PNP devices exhibit a port voltage that is much higher than the power supply voltage or a negative voltage that is lower than the ground potential when an ESD event occurs. In this case, the parasitic PN junction of the PNP device will conduct, resulting in a large leakage current at the port, which makes the port signal incomplete and affects the actual use of the entire chip. Furthermore, in some applications, there are problems such as small leakage current and slow ESD response. Summary of the Invention

[0004] The purpose of this invention is to provide an ESD protection device that can withstand positive and negative high voltages, as well as its preparation method and electronic equipment, in order to solve the problems that existing PNP-type ESD protection devices cannot withstand positive and negative high voltages, cause parasitic leakage to the substrate, and have breakdown delays.

[0005] To address the aforementioned technical problems, this application provides an ESD protection device resistant to both positive and negative high voltages, comprising:

[0006] A substrate, a buried layer formed in the substrate, and an epitaxial layer formed on the substrate and the buried layer;

[0007] A first high-pressure trap and a second high-pressure trap are formed on the buried layer; wherein, the first high-pressure trap has a ring structure, the second high-pressure trap has a shaped structure, the outer side of the first high-pressure trap is aligned with the outer side of the buried layer, and the second high-pressure trap is formed on the inner side of the first high-pressure trap;

[0008] The first deep well and the second deep well are respectively formed in the first high-pressure well and the second high-pressure well;

[0009] The first well region and the second well region are respectively formed in the first deep well and the second deep well;

[0010] The first active region and the second active region are respectively formed in the first well region and the second well region; wherein, the first deep well, the first well region and the first active region are ring structures, and the second deep well, the second well region and the second active region are eye-shaped structures;

[0011] The third deep well, the fourth deep well, the fifth deep well, and the sixth deep well; wherein the third deep well is located between the first high-pressure well and the second high-pressure well, and the fourth deep well, the fifth deep well, and the sixth deep well are respectively located within the three hole structures of the second high-pressure well;

[0012] The third well region, the fourth well region, the fifth well region, and the sixth well region are respectively formed in the third deep well, the fourth deep well, the fifth deep well, and the sixth deep well;

[0013] The third active region, the fourth active region, the fifth active region, and the sixth active region are respectively formed in the third well region, the fourth well region, the fifth well region, and the sixth well region;

[0014] A seventh well region formed outside the first high-voltage well and a seventh active region formed within the seventh well region; wherein the seventh well region, the seventh active region, the third deep well, the fourth deep well, the fifth deep well, the sixth deep well, the third well region, the fourth well region, the fifth well region, the sixth well region, the third active region, the fourth active region, the fifth active region, the sixth active region, the substrate, and the epitaxial layer have the same doping type, and are opposite to the doping type of the first high-voltage well, the second high-voltage well, the first deep well, the second deep well, the first well region, the second well region, the first active region, the second active region, and the buried layer.

[0015] In one embodiment, both the first high-pressure trap and the second high-pressure trap are in contact with the burial layer;

[0016] The first active region and the second active region are connected to the intermediate node metal electrode via a metal connecting line.

[0017] In one embodiment, the third active region is connected to the intermediate node metal electrode via a metal connection line;

[0018] The seventh active region is connected to the first metal electrode;

[0019] The fourth active region and the sixth active region are connected to the first metal electrode via a metal connecting wire;

[0020] The fifth active region is connected to the second metal electrode.

[0021] In one embodiment, the ESD protection device further includes:

[0022] A first resistor is connected between the first metal electrode and the intermediate node metal electrode.

[0023] In one embodiment, the ESD protection device further includes:

[0024] A second resistor is connected between the second metal electrode and the intermediate node metal electrode.

[0025] In one embodiment, the first resistor is an on-chip integrated resistor or an off-chip discrete resistor.

[0026] In one embodiment, the seventh well region, the seventh active region, the third deep well, the fourth deep well, the fifth deep well, the sixth deep well, the third well region, the fourth well region, the fifth well region, the sixth well region, the third active region, the fourth active region, the fifth active region, the sixth active region, the substrate, and the epitaxial layer are P-type doped;

[0027] The first high-voltage well, the second high-voltage well, the first deep well, the second deep well, the first well region, the second well region, the first active region, the second active region, and the buried layer are N-type doped.

[0028] A second aspect of the embodiments of the present application further provides a method for manufacturing an ESD protection device capable of withstanding positive and negative high voltages. The manufacturing method includes:

[0029] Forming a first buried layer in a substrate, and forming an epitaxial layer on the substrate and the first buried layer;

[0030] Forming a first high-voltage well and a second high-voltage well in contact with the buried layer in the epitaxial layer; wherein, the first high-voltage well is a ring structure, the second high-voltage well is a rectangular structure with a hole in the middle, the outside of the first high-voltage well is aligned with the outside of the buried layer, and the second high-voltage well is formed inside the first high-voltage well;

[0031] Respectively forming a first deep well and a second deep well in the first high-voltage well and the second high-voltage well;

[0032] Respectively forming a first well region and a second well region in the first deep well and the second deep well;

[0033] Respectively forming a first active region and a second active region in the first well region and the second well region; wherein, the first deep well, the first well region, and the first active region are ring structures, and the second deep well, the second well region, and the second active region are rectangular structures with a hole in the middle;

[0034] A third deep well, a fourth deep well, a fifth deep well, and a sixth deep well are formed within the epitaxial layer; wherein the third deep well is located between the first high-pressure well and the second high-pressure well, and the fourth deep well, the fifth deep well, and the sixth deep well are respectively located within the three hole structures of the second high-pressure well;

[0035] A third well region, a fourth well region, a fifth well region, and a sixth well region are respectively formed in the third deep well, the fourth deep well, the fifth deep well, and the sixth deep well, and a seventh well region is formed outside the first high-pressure well;

[0036] A third active region, a fourth active region, a fifth active region, a sixth active region, and a seventh active region are respectively formed in the third well region, the fourth well region, the fifth well region, the sixth well region, and the seventh well region; wherein the seventh well region, the seventh active region, the third deep well, the fourth deep well, the fifth deep well, the sixth deep well, the third well region, the fourth well region, the fifth well region, the sixth well region, the third active region, the fourth active region, the fifth active region, the sixth active region, the substrate, and the epitaxial layer have the same doping type, and are opposite to the doping type of the first high-voltage well, the second high-voltage well, the first deep well, the second deep well, the first well region, the second well region, the first active region, the second active region, and the buried layer.

[0037] In one embodiment, the seventh well region, the seventh active region, the third deep well, the fourth deep well, the fifth deep well, the sixth deep well, the third well region, the fourth well region, the fifth well region, the sixth well region, the third active region, the fourth active region, the fifth active region, the sixth active region, the first high-pressure well, the second high-pressure well, the first deep well, the second deep well, the first well region, the second well region, the first active region, the second active region, and the buried layer are formed by ion implantation or diffusion.

[0038] A third aspect of this application also provides an electronic device, which includes an ESD protection device as described in any of the above embodiments; or includes an ESD protection device prepared by the preparation method described in any of the above embodiments.

[0039] This invention provides an ESD protection device resistant to positive and negative high voltages, its fabrication method, and an electronic device. The ESD protection device includes a substrate, a buried layer formed in the substrate, and an epitaxial layer formed on the substrate and the buried layer. A first high-voltage well with a ring structure and in contact with the buried layer and a second high-voltage well with a V-shaped structure are formed on the buried layer. The second high-voltage well is formed inside the first high-voltage well. The doping concentration between the first high-voltage well and the first active region gradually decreases, and the doping concentration between the second high-voltage well and the second active region gradually decreases. Then, a third, fourth, fifth, sixth, and seventh active regions are formed inside and outside the first high-voltage well and within the hole structure of the second high-voltage well. By connecting the active regions or connecting resistors between the active regions, the leakage current of the PNP device can be effectively reduced and the port can be ensured to work normally under positive and negative voltages. It can also eliminate the PNP breakdown delay phenomenon, so that the ESD time can meet the requirements of fast response. Attached Figure Description

[0040] Figure 1 A top view of the ESD protection device resistant to positive and negative high voltage provided in an embodiment of the present invention;

[0041] Figure 2 A top view and a cross-sectional view of the ESD protection device resistant to positive and negative high voltage provided in an embodiment of the present invention at the position of the dashed line A-A';

[0042] Figure 3 A schematic diagram illustrating the application of the ESD protection device resistant to positive and negative high voltage provided in an embodiment of the present invention;

[0043] Figure 4 and Figure 5 The equivalent circuit diagram of the ESD protection device with positive and negative high voltage provided in the embodiment of the present invention;

[0044] Figure 6 This is a schematic flowchart illustrating the fabrication method of the ESD protection device resistant to positive and negative high voltage provided in an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0046] This invention provides an ESD protection device that can withstand positive and negative high voltages, effectively ensuring that the port operates normally under positive and negative voltages. It features low leakage current and can also eliminate the PNP breakdown delay phenomenon, enabling a rapid response when ESD occurs.

[0047] Figure 1 This is a schematic diagram of a horizontal cross-section of the ESD protection device in this embodiment. Figure 2 for Figure 1 See the schematic diagram of the vertical cross-section of the dashed line AA' in the diagram. Figure 1 and Figure 2 As shown, the ESD protection device in this embodiment includes: a substrate 101, a buried layer 102, an epitaxial layer 103, a first high-voltage well 201, a second high-voltage well 202, a first deep well 301, a second deep well 302, a third deep well 303, a fourth deep well 304, a fifth deep well 305, a sixth deep well 306, a first well region 401, a second well region 402, a third well region 403, a fourth well region 404, a fifth well region 405, a sixth well region 406, a seventh well region 407, a first active region 501, a second active region 502, a third active region 503, a fourth active region 504, a fifth active region 505, a sixth active region 506, and a seventh active region 507.

[0048] Specifically, a buried layer 102 is formed in a substrate 101, and an epitaxial layer 103 is formed on the substrate 101 and the buried layer 102. The buried layer 102 has the opposite doping type to the substrate 101, and the epitaxial layer 103 has the same doping type as the substrate 101. The width of the buried layer 102 is smaller than the width of the substrate 101, and the width of the epitaxial layer 103 is larger than the width of the buried layer 102.

[0049] The first high-pressure trap 201 and the second high-pressure trap 202 are formed on the buried layer 102, combined with Figure 1 As shown, the first high-pressure well 201 has a ring structure, and the second high-pressure well 202 has a shaped structure. The outer side of the first high-pressure well 201 is aligned with the outer side of the buried layer 102. The second high-pressure well 202 is formed inside the first high-pressure well 201, and the second high-pressure well 202 and the first high-pressure well 201 do not contact each other. Since the second high-pressure well has a shaped structure, it has three holes, and the epitaxial layer 103 is filled in the three holes. The doping type of the first high-pressure well 201 and the second high-pressure well 202 is different from the doping type of the epitaxial layer 103.

[0050] The first deep well 301 and the second deep well 302 are formed in the first high-pressure well 201 and the second high-pressure well 202, respectively. The first well region 401 and the second well region 402 are formed in the first deep well 301 and the second deep well 302, respectively. The first active region 501 and the second active region 502 are formed in the first well region 401 and the second well region 402, respectively.

[0051] In this embodiment, a first deep well 301 is formed within a first high-pressure well 201, a first well region 401 is formed within a first deep well 301, and a first active region 501 is formed within a first well region 401. The structures of the first deep well 301, the first well region 401, and the first active region 501 are the same as those of the first high-pressure well 201, all being annular structures. A second deep well 302 is formed within a second high-pressure well 202, a second well region 402 is formed within a second deep well 302, and a second active region 502 is formed within a second well region 402. The structures of the second deep well 302, the second well region 402, and the second active region 502 are the same as those of the second high-pressure well 202, all being U-shaped structures.

[0052] In this embodiment, the third deep well 303 is located between the first high-pressure well 201 and the second high-pressure well 202, and the third deep well 303 has an annular structure. The fourth deep well 304, the fifth deep well 305, and the sixth deep well 306 are respectively located within the three hole structures of the second high-pressure well 202. The third well region 403, the fourth well region 404, the fifth well region 405, and the sixth well region 406 are respectively formed within the third deep well 303, the fourth deep well 304, the fifth deep well 305, and the sixth deep well 306. The third active region 503, the fourth active region 504, the fifth active region 505, and the sixth active region 506 are respectively formed within the third well region 403, the fourth well region 404, the fifth well region 405, and the sixth well region 406. The seventh well region 407 is formed outside the first high-pressure well 201, and the seventh active region 507 is formed within the seventh well region 407.

[0053] In this embodiment, the seventh well region 407, the seventh active region 507, the third deep well 303, the fourth deep well 304, the fifth deep well 305, the sixth deep well 306, the third well region 403, the fourth well region 404, the fifth well region 405, the sixth well region 406, the third active region 503, the fourth active region 504, the fifth active region 505, the sixth active region 506, the substrate 101, and the epitaxial layer 103 have the same doping type, and are opposite to the doping type of the first high-voltage well 201, the second high-voltage well 202, the first deep well 301, the second deep well 302, the first well region 401, the second well region 402, the first active region 501, the second active region 502, and the buried layer 102.

[0054] The doping types include N-type doping and P-type doping. For example, the seventh well region 407, the seventh active region 507, the third deep well 303, the fourth deep well 304, the fifth deep well 305, the sixth deep well 306, the third well region 403, the fourth well region 404, the fifth well region 405, the sixth well region 406, the third active region 503, the fourth active region 504, the fifth active region 505, the sixth active region 506, the substrate 101, and the epitaxial layer 103 are P-type doped. Then, the first high-voltage well 201, the second high-voltage well 202, the first deep well 301, the second deep well 302, the first well region 401, the second well region 402, the first active region 501, the second active region 502, and the buried layer... Layer 102 is N-type doped. The seventh well region 407, the seventh active region 507, the third deep well 303, the fourth deep well 304, the fifth deep well 305, the sixth deep well 306, the third well region 403, the fourth well region 404, the fifth well region 405, the sixth well region 406, the third active region 503, the fourth active region 504, the fifth active region 505, the sixth active region 506, the substrate 101, and the epitaxial layer 103 are all N-type doped. Therefore, the first high-voltage well 201, the second high-voltage well 202, the first deep well 301, the second deep well 302, the first well region 401, the second well region 402, the first active region 501, the second active region 502, and the buried layer 102 are P-type doped. By interchangeing the doping types (P-type and N-type), the same ESD protection device with high sustaining voltage and resistance to both positive and negative high voltages can be obtained.

[0055] In one embodiment, the epitaxial layer 103 and the substrate 101 can be P-type doped, and the buried layer 102 can be N-type doped.

[0056] In one embodiment, the buried layer 102 can be P-type doped, and the epitaxial layer 103 and the substrate 101 can be N-type doped.

[0057] In one embodiment, see Figure 2 As shown, the width of the first deep well 301 is smaller than the width of the first high-pressure well 201, the depth of the first deep well 301 is smaller than the depth of the first high-pressure well 201, the width of the first well region 401 is smaller than the width of the first deep well 301, the depth of the first well region 401 is smaller than the depth of the first deep well 301, the width of the first active region 501 is smaller than the width of the first well region 401, and the depth of the first active region 501 is smaller than the depth of the first well region 401.

[0058] In one embodiment, see Figure 2 As shown, the first active region 501 is located in the central region of the first well region 401, the first well region 401 is located in the central region of the first deep well 301, and the first deep well 301 is located in the central region of the first high-pressure well 201.

[0059] In one embodiment, the doping concentration of the first deep well 301 is greater than the doping concentration of the first high-voltage well 201, the doping concentration of the first well region 401 is greater than the doping concentration of the first deep well 301, and the doping concentration of the first active region 501 is greater than the doping concentration of the first well region 401.

[0060] In one embodiment, see Figure 2 As shown, the width of the second deep well 302 is smaller than the width of the second high-pressure well 202, the depth of the second deep well 302 is smaller than the depth of the second high-pressure well 202, the width of the second well region 402 is smaller than the width of the second deep well 302, the depth of the second well region 402 is smaller than the depth of the second deep well 302, the width of the second active region 501 is smaller than the width of the second well region 402, and the depth of the second active region 501 is smaller than the depth of the second well region 402.

[0061] In one embodiment, see Figure 1 As shown, the second active region 501 is located in the central region of the second well region 402, the second well region 402 is located in the central region of the second deep well 302, and the second deep well 302 is located in the central region of the second high-pressure well 202.

[0062] In one embodiment, the doping concentration of the second deep well 302 is greater than the doping concentration of the second high-voltage well 202, the doping concentration of the second well region 402 is greater than the doping concentration of the second deep well 302, and the doping concentration of the second active region 501 is greater than the doping concentration of the second well region 402.

[0063] In one embodiment, the third deep well 303 is located between the first high-pressure well 201 and the second high-pressure well 202, and the third deep well 303 does not contact the first high-pressure well 201 and the second high-pressure well 202. The distance between the third deep well 303 and the first high-pressure well 201 and the second high-pressure well 202 is the same.

[0064] In one embodiment, the depth of the third deep well 303 is less than the depth of the first high-pressure well 201, and it does not contact the burial layer 102.

[0065] In one embodiment, the third well region 403 is formed within the third deep well 303, and the depth of the third well region 403 is less than the depth of the third deep well 303, the width of the third well region 403 is equal to the width of the third deep well 303, and the width of the third active region 503 is less than the width of the third well region 403.

[0066] In one embodiment, the fourth deep well 304 is located within a hole structure of the second high-pressure well 202 and does not contact the second high-pressure well 202. An epitaxial layer 103 is filled between the fourth deep well 304 and the second high-pressure well 202.

[0067] In one embodiment, the depth of the fourth deep well 304 is less than the depth of the second high-pressure well 202, and it does not contact the burial layer 102.

[0068] In one embodiment, the fourth well region 404 is formed within the fourth deep well 304, and the depth of the fourth well region 404 is less than the depth of the fourth deep well 304, the width of the fourth well region 404 is equal to the width of the fourth deep well 304, and the width of the fourth active region 504 is less than the width of the fourth well region 404.

[0069] In one embodiment, the fifth deep well 305 is located within a hole structure of the second high-pressure well 202 and is not in contact with the second high-pressure well 202. An epitaxial layer 10 is filled between the fifth deep well 305 and the second high-pressure well 202.

[0070] In one embodiment, the depth of the fifth deep well 305 is less than the depth of the second high-pressure well 202, and it does not contact the burial layer 102.

[0071] In one embodiment, the fifth well region 405 is formed within the fifth deep well 305, and the depth of the fifth well region 405 is less than the depth of the fifth deep well 305, the width of the fifth well region 405 is equal to the width of the fifth deep well 305, and the width of the fifth active region 505 is less than the width of the fifth well region 405.

[0072] In one embodiment, the sixth deep well 306 is located within a hole structure of the second high-pressure well 202 and is not in contact with the second high-pressure well 202. An epitaxial layer 10 is filled between the sixth deep well 306 and the second high-pressure well 202.

[0073] In one embodiment, the depth of the sixth deep well 306 is less than the depth of the second high-pressure well 202, and it does not contact the burial layer 102.

[0074] In one embodiment, the sixth well region 406 is formed within the sixth deep well 306, and the depth of the sixth well region 406 is less than the depth of the sixth deep well 306, the width of the sixth well region 406 is equal to the width of the sixth deep well 306, and the width of the sixth active region 506 is less than the width of the fourth well region 404.

[0075] In one embodiment, the three hole structures of the second high-pressure trap 202 are arranged side by side, the fifth active region 505 is located in the middle hole structure of the three hole structures of the second high-pressure trap 202, and the fourth active region 504 and the sixth active region 506 are located in the hole structures on both sides of the fifth active region 505, respectively.

[0076] In one embodiment, the fourth well region 404 and the sixth well region 406 are arranged symmetrically with respect to the fifth well region 405.

[0077] In one embodiment, the fourth well region 404, the fifth well region 405, and the sixth well region 406 have the same shape and doping concentration.

[0078] In one embodiment, the seventh well region 407 is formed outside the first high-voltage well 201, and the seventh well region 407 is not in contact with the first high-voltage well 201. The seventh well region 407 has an annular structure, and the seventh active region 507 is formed within the seventh well region 407.

[0079] In one embodiment, the annular structure in the above embodiment can be a square annular structure or a circular annular structure.

[0080] In one embodiment, the "mu" character-shaped structure in the above embodiment can be formed by combining an annular structure with two rectangular structures. For example, the two rectangular structures are formed within the annular structure and are not in contact with each other, and the two ends of the two rectangular structures are respectively in contact with the annular structure. Similarly, the hole structure within the "mu" character-shaped structure in the above embodiment can be a square structure or a circle.

[0081] In one embodiment, the three hole structures in the second high-voltage well 202 are arranged side by side, and each hole structure has a well region that is not in contact with the hole structure itself. For example, the fourth well region 404 is provided in the first hole structure in the second high-voltage well 202, the fifth well region 405 is provided in the second hole structure in the second high-voltage well 202, and the sixth well region 406 is provided in the third hole structure in the second high-voltage well 202.

[0082] In one embodiment, the distance between the well region in each hole structure and the hole structure where it is located is equal.

[0083] In one embodiment, the fourth well region 404, the fifth well region 405, and the sixth well region 406 are rectangular structures, and their left sides are parallel to the left sides of the corresponding hole structures, or their right sides are parallel to the right sides of the corresponding hole structures, or their left sides are parallel to the left sides of the corresponding hole structures and their right sides are parallel to the right sides of the corresponding hole structures.

[0084] The embodiment of the present invention provides an ESD protection device that is resistant to positive and negative high voltages and has a high holding voltage, which can effectively ensure that the port operates normally under positive and negative voltages, has the characteristic of low leakage current, and can also eliminate the PNP breakdown delay phenomenon, enabling a quick response when an ESD event occurs.

[0085] The following describes the implementation of the present invention in detail with reference to specific embodiments:

[0086] In one embodiment, refer to Figure 3As shown, both the first high-pressure trap 201 and the second high-pressure trap 202 are in contact with the buried layer 102, and the first active region 501 and the second active region 502 are connected to the intermediate node metal electrode C through a metal connecting line.

[0087] In this embodiment, the first high-voltage trap 201 and the second high-voltage trap 202 are in contact with each other through the N-type buried layer 102, and the first active region 501 and the second active region 502 are in contact with each other through the metal connecting wire to form an intermediate node, thereby forming an isolation ring structure. This isolation ring has the characteristic of low leakage current and can effectively prevent problems such as parasitic transistors.

[0088] In one embodiment, the third active region 503 is connected to the intermediate node metal electrode C via a metal connection line, the seventh active region 507 is connected to the first metal electrode D, the fourth active region 504 and the sixth active region 506 are both connected to the first metal electrode D via a metal connection line, and the fifth active region 505 is connected to the second metal electrode B.

[0089] In practical applications, the first metal electrode D can be grounded, and the second metal electrode B can be connected to a power source, which can output positive or negative voltage.

[0090] In one embodiment, the ESD protection device further includes a first resistor R1, which is connected between the first metal electrode D and the intermediate node metal electrode C.

[0091] In one embodiment, the ESD protection device in this embodiment further includes a second resistor R2, which is connected between the second metal electrode B and the intermediate node metal electrode C.

[0092] In one embodiment, the first resistor R1 and the second resistor R2 may include, but are not limited to, on-chip integrated resistors and off-chip discrete resistors.

[0093] In specific applications, the intermediate node metal electrode C can be connected to the second metal electrode B (e.g., the anode of the device) with a second resistor R2, or the intermediate node metal electrode C can be connected to the first metal electrode D (e.g., the cathode of the device) with a first resistor R1, or the intermediate node metal electrode C can be connected to both the second metal electrode B (e.g., the anode of the device) and the first metal electrode D (e.g., the cathode of the device) with a second resistor R2 and a first resistor R1.

[0094] In the ESD protection device, the working principle of the device is explained below with the seventh well region 407, the seventh active region 507, the third deep well 303, the fourth deep well 304, the fifth deep well 305, the sixth deep well 306, the third well region 403, the fourth well region 404, the fifth well region 405, the sixth well region 406, the third active region 503, the fourth active region 504, the fifth active region 505, the sixth active region 506, the substrate 101, and the epitaxial layer 103 being P-type doped, and the first high-voltage well 201, the second high-voltage well 202, the first deep well 301, the second deep well 302, the first well region 401, the second well region 402, the first active region 501, the second active region 502, and the buried layer 102 being N-type doped. The equivalent circuit diagram is shown below. Figure 4 and Figure 5 As shown.

[0095] In this structure, since the PNP structure is the same from GND (first metal electrode D) to PAD (second metal electrode B) and from PAD to GND, this structure can withstand both positive and negative voltages. When an ESD event occurs, if the PAD voltage is higher than the GND voltage and reaches the breakdown voltage of the PN junction formed by the second well region 402 (N-well), the second deep well 302 (deep N-well), the second high-voltage well 202 (high-voltage N-well), and the fourth well region 404 (P-well) and the fourth deep well 304 (deep P-well), the PN junction breaks down. Current flows from the second high-voltage well 202 (high-voltage N-well) to the fourth well region 404 (P-well), triggering the lateral PNP transistor.

[0096] When the GND voltage is higher than the PAD voltage and reaches the breakdown voltage of the PN junction formed by the second well region 402 (N-well), the second deep well 302 (deep N-well), the second high-voltage well 202 (high-voltage N-well), the fifth well region 405 (P-well), and the fifth deep well 305 (deep P-well), the PN junction breaks down, and the current flows from the second high-voltage well 202 (high-voltage N-well) to the fifth well region 405 (P-well), triggering the lateral PNP transistor.

[0097] Since the second high-voltage well 202 (high-voltage N-well) is a lightly doped well, the PN junction formed by the second high-voltage well 202 (high-voltage N-well) and the fourth well region 404 (P-well), the fifth well region 405 (P-well), and the sixth well region 406 (P-well) has a very high breakdown voltage, which can achieve the characteristic of high voltage resistance.

[0098] In one embodiment, the ESD protection device is manufactured using the BCDMOS process, and its device index is n, where n≥1.

[0099] As an embodiment of the present invention, the ESD protection device can be manufactured using a BCD 0.5µm process. Its structure utilizes a PN junction formed by a high-voltage N-well and a P-well for triggering. The reverse breakdown voltage of this PN junction is 90V, thus enabling a forward trigger voltage of 90V and a reverse trigger voltage of 90V. It can provide protection against positive and negative high-voltage ESD. Because it is surrounded by a high-voltage N-well ring and a deep P-well ring, and a resistor is connected to the grounding PAD or GND or both in the middle, the device has the characteristics of low leakage current and no trigger delay.

[0100] It is conceivable that by simultaneously interchangeing the doping types (P-type and N-type), ESD protection devices with the same performance, capable of withstanding positive and negative high voltages and high sustaining voltages, can also be obtained.

[0101] This invention provides an ESD protection device that can withstand positive and negative high voltages, effectively ensuring that the port operates normally under positive and negative voltages. It features low leakage current and can also eliminate the PNP breakdown delay phenomenon, enabling a rapid response when ESD occurs.

[0102] Another objective of this invention is to provide a method for preparing an ESD protection device resistant to positive and negative high voltages, comprising steps S101 to S106.

[0103] In step S101, a first buried layer is formed in the substrate, and an epitaxial layer is formed on the substrate and the first buried layer. A first high-voltage well and a second high-voltage well are formed on the epitaxial layer in contact with the buried layer.

[0104] In this embodiment, combined with Figure 1 and Figure 2 As shown, a buried layer 102 is formed in a substrate 101, and an epitaxial layer 103 is formed on the substrate 101 and the buried layer 102. The buried layer 102 has the opposite doping type to the substrate 101, and the epitaxial layer 103 has the same doping type as the substrate 101. The width of the buried layer 102 is smaller than the width of the substrate 101, and the width of the epitaxial layer 103 is larger than the width of the buried layer 102.

[0105] The first high-pressure trap 201 and the second high-pressure trap 202 are formed on the buried layer 102, combined with Figure 1 As shown, the first high-pressure well 201 has a ring structure, and the second high-pressure well 202 has a shaped structure. The outer side of the first high-pressure well 201 is aligned with the outer side of the buried layer 102. The second high-pressure well 202 is formed inside the first high-pressure well 201, and the second high-pressure well 202 and the first high-pressure well 201 do not contact each other. Since the second high-pressure well has a shaped structure, it has three holes, and the epitaxial layer 103 is filled in the three holes. The doping type of the first high-pressure well 201 and the second high-pressure well 202 is different from the doping type of the epitaxial layer 103.

[0106] In step S102, a first deep well and a second deep well are formed in the first high-pressure well and the second high-pressure well, respectively, and a first well region and a second well region are formed in the first deep well and the second deep well, respectively.

[0107] In step S103, a first active region and a second active region are formed in the first well region and the second well region, respectively.

[0108] In this embodiment, combined with Figure 1 and Figure 2 As shown, the first deep well 301 and the second deep well 302 are formed in the first high-pressure well 201 and the second high-pressure well 202, respectively; the first well region 401 and the second well region 402 are formed in the first deep well 301 and the second deep well 302, respectively; and the first active region 501 and the second active region 502 are formed in the first well region 401 and the second well region 402, respectively.

[0109] A first deep well 301 is formed within a first high-pressure well 201, a first well region 401 is formed within a first deep well 301, and a first active region 501 is formed within a first well region 401. The structures of the first deep well 301, the first well region 401, and the first active region 501 are the same as those of the first high-pressure well 201, all being annular structures. A second deep well 302 is formed within a second high-pressure well 202, a second well region 402 is formed within a second deep well 302, and a second active region 502 is formed within a second well region 402. The structures of the second deep well 302, the second well region 402, and the second active region 502 are the same as those of the second high-pressure well 202, all being U-shaped structures.

[0110] In one embodiment, the buried layer 102 can be P-type doped, and the epitaxial layer 103 and the substrate 101 can be N-type doped.

[0111] In one embodiment, see Figure 2 As shown, the width of the first deep well 301 is smaller than the width of the first high-pressure well 201, the depth of the first deep well 301 is smaller than the depth of the first high-pressure well 201, the width of the first well region 401 is smaller than the width of the first deep well 301, the depth of the first well region 401 is smaller than the depth of the first deep well 301, the width of the first active region 501 is smaller than the width of the first well region 401, and the depth of the first active region 501 is smaller than the depth of the first well region 401.

[0112] In one embodiment, see Figure 2 As shown, the first active region 501 is located in the central region of the first well region 401, the first well region 401 is located in the central region of the first deep well 301, and the first deep well 301 is located in the central region of the first high-pressure well 201.

[0113] In one embodiment, the doping concentration of the first deep well 301 is greater than the doping concentration of the first high-voltage well 201, the doping concentration of the first well region 401 is greater than the doping concentration of the first deep well 301, and the doping concentration of the first active region 501 is greater than the doping concentration of the first well region 401.

[0114] In one embodiment, see Figure 2 As shown, the width of the second deep well 302 is smaller than the width of the second high-pressure well 202, the depth of the second deep well 302 is smaller than the depth of the second high-pressure well 202, the width of the second well region 402 is smaller than the width of the second deep well 302, the depth of the second well region 402 is smaller than the depth of the second deep well 302, the width of the second active region 501 is smaller than the width of the second well region 402, and the depth of the second active region 501 is smaller than the depth of the second well region 402.

[0115] In one embodiment, see Figure 1 As shown, the second active region 501 is located in the central region of the second well region 402, the second well region 402 is located in the central region of the second deep well 302, and the second deep well 302 is located in the central region of the second high-pressure well 202.

[0116] In one embodiment, the doping concentration of the second deep well 302 is greater than the doping concentration of the second high-voltage well 202, the doping concentration of the second well region 402 is greater than the doping concentration of the second deep well 302, and the doping concentration of the second active region 501 is greater than the doping concentration of the second well region 402.

[0117] In step S104, a third deep well, a fourth deep well, a fifth deep well, and a sixth deep well are formed within the epitaxial layer.

[0118] In this embodiment, the third deep well 303 is located between the first high-pressure well 201 and the second high-pressure well 202, and the third deep well 303 has an annular structure. The fourth deep well 304, the fifth deep well 305, and the sixth deep well 306 are respectively located in the three hole structures of the second high-pressure well 202.

[0119] In one embodiment, the third deep well 303 is located between the first high-pressure well 201 and the second high-pressure well 202, and the third deep well 303 does not contact the first high-pressure well 201 and the second high-pressure well 202. The distance between the third deep well 303 and the first high-pressure well 201 and the second high-pressure well 202 is the same.

[0120] In one embodiment, the depth of the third deep well 303 is less than the depth of the first high-pressure well 201, and it does not contact the burial layer 102.

[0121] In one embodiment, the fourth deep well 304 is located within a hole structure of the second high-pressure well 202 and is not in contact with the second high-pressure well 202. An epitaxial layer 10 is filled between the fourth deep well 304 and the second high-pressure well 202.

[0122] In one embodiment, the depth of the fourth deep well 304 is less than the depth of the second high-pressure well 202, and it does not contact the burial layer 102.

[0123] In one embodiment, the fifth deep well 305 is located within a hole structure of the second high-pressure well 202 and is not in contact with the second high-pressure well 202. An epitaxial layer 10 is filled between the fifth deep well 305 and the second high-pressure well 202.

[0124] In one embodiment, the depth of the fifth deep well 305 is less than the depth of the second high-pressure well 202, and it does not contact the burial layer 102.

[0125] In one embodiment, the sixth deep well 306 is located within a hole structure of the second high-pressure well 202 and is not in contact with the second high-pressure well 202. An epitaxial layer 10 is filled between the sixth deep well 306 and the second high-pressure well 202.

[0126] In one embodiment, the depth of the sixth deep well 306 is less than the depth of the second high-pressure well 202, and it does not contact the burial layer 102.

[0127] In step S105, a third well region, a fourth well region, a fifth well region, and a sixth well region are formed in the third deep well, the fourth deep well, the fifth deep well, and the sixth deep well, respectively, and a seventh well region is formed outside the first high-pressure well.

[0128] In this embodiment, the third well region 403, the fourth well region 404, the fifth well region 405, and the sixth well region 406 are respectively formed in the third deep well 303, the fourth deep well 304, the fifth deep well 305, and the sixth deep well 306.

[0129] In one embodiment, the third well region 403 is formed within the third deep well 303, and the depth of the third well region 403 is less than the depth of the third deep well 303, the width of the third well region 403 is equal to the width of the third deep well 303, and the width of the third active region 503 is less than the width of the third well region 403.

[0130] In one embodiment, the fourth well region 404 is formed within the fourth deep well 304, and the depth of the fourth well region 404 is less than the depth of the fourth deep well 304, the width of the fourth well region 404 is equal to the width of the fourth deep well 304, and the width of the fourth active region 504 is less than the width of the fourth well region 404.

[0131] In one embodiment, the fifth well region 405 is formed within the fifth deep well 305, and the depth of the fifth well region 405 is less than the depth of the fifth deep well 305, the width of the fifth well region 405 is equal to the width of the fifth deep well 305, and the width of the fifth active region 505 is less than the width of the fifth well region 405.

[0132] In one embodiment, the sixth well region 406 is formed within the sixth deep well 306, and the depth of the sixth well region 406 is less than the depth of the sixth deep well 306, the width of the sixth well region 406 is equal to the width of the sixth deep well 306, and the width of the sixth active region 506 is less than the width of the fourth well region 404.

[0133] In step S106, a third active region, a fourth active region, a fifth active region, a sixth active region, and a seventh active region are formed in the third well region, the fourth well region, the fifth well region, the sixth well region, and the seventh well region, respectively.

[0134] In this embodiment, the third active region 503, the fourth active region 504, the fifth active region 505, and the sixth active region 506 are respectively formed in the third well region 403, the fourth well region 404, the fifth well region 405, and the sixth well region 406. The seventh well region 407 is formed outside the first high-pressure well 201, and the seventh active region 507 is formed in the seventh well region 407.

[0135] In this embodiment, the three hole structures of the second high-pressure trap 202 are arranged side by side, the fifth active region 505 is located in the middle hole structure of the three hole structures of the second high-pressure trap 202, and the fourth active region 504 and the sixth active region 506 are located in the hole structures on both sides of the fifth active region 505, respectively.

[0136] The doping types of the seventh well region 407, the seventh active region 507, the third deep well 303, the fourth deep well 304, the fifth deep well 305, the sixth deep well 306, the third well region 403, the fourth well region 404, the fifth well region 405, the sixth well region 406, the third active region 503, the fourth active region 504, the fifth active region 505, the sixth active region 506, the substrate 101, and the epitaxial layer 103 are the same, and are opposite to the doping types of the first high-voltage well 201, the second high-voltage well 202, the first deep well 301, the second deep well 302, the first well region 401, the second well region 402, the first active region 501, the second active region 502, and the buried layer 102.

[0137] In one embodiment, the first high-pressure trap 201, the second high-pressure trap 202, the first deep trap 301, the second deep trap 302, the first trap region 401, the second trap region 402, the first active region 501, the second active region 502, the buried layer 102, and the third deep trap 303 and the third trap region 403 form an isolation.

[0138] In one embodiment, the annular structure in the above embodiment may be a square annular structure or a circular annular structure.

[0139] In one embodiment, the eye-shaped structure in the above embodiment may be formed by combining an annular structure and two rectangular structures. For example, the two rectangular structures are formed within the annular structure and do not contact each other, and both ends of the two rectangular structures are in contact with the annular structure. Similarly, the hole structure within the eye-shaped structure in the above embodiment may be a square structure or a circle.

[0140] In one embodiment, the seventh well region 407, the seventh active region 507, the third deep well 303, the fourth deep well 304, the fifth deep well 305, the sixth deep well 306, the third well region 403, the fourth well region 404, the fifth well region 405, the sixth well region 406, the third active region 503, the fourth active region 504, the fifth active region 505, the sixth active region 506, the substrate 101, the epitaxial layer 103, the first high-voltage well 201, the second high-voltage well 202, the first deep well 301, the second deep well 302, the first well region 401, the second well region 402, the first active region 501, the second active region 502, and the buried layer 102 may be formed by ion implantation or diffusion.

[0141] In specific applications, the first active region 501 and the second active region 502 are connected together through a metal connection line to form an intermediate node, thereby forming an isolation ring structure. This isolation ring has the characteristic of low leakage and can effectively prevent problems such as parasitic transistors.

[0142] In specific applications, a second resistor R2 may be connected between the intermediate node metal electrode C and the second metal electrode B (such as the anode of the device), or a first resistor R1 may be connected between the intermediate node metal electrode C and the first metal electrode D (such as the cathode of the device), or a second resistor R2 and a first resistor R1 may be connected between the intermediate node metal electrode C and both the second metal electrode B (such as the anode of the device) and the first metal electrode D (such as the cathode of the device).

[0143] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the above division of each doping region is used for illustration. In actual applications, the above functional regions can be allocated to different doping regions as needed, that is, the internal structure of the device is divided into different doping regions to complete all or part of the functions described above.

[0144] In the embodiments, the doped regions can be integrated into one functional region, or each doped region can exist independently, or two or more doped regions can be integrated into one functional region. The integrated functional region can be implemented using the same type of dopant ion or multiple types of dopant ions. Furthermore, the specific names of each doped region are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the doped region in the fabrication method of the above device can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0145] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. An ESD protection device resistant to positive and negative high voltages, characterized in that, The ESD protection device includes: Substrate, and buried layer formed in the substrate; An epitaxial layer formed on the substrate and the buried layer; A first high-pressure trap and a second high-pressure trap are formed on the buried layer; wherein, the first high-pressure trap has a ring structure, the second high-pressure trap has a shaped structure, the outer side of the first high-pressure trap is aligned with the outer side of the buried layer, and the second high-pressure trap is formed on the inner side of the first high-pressure trap; The first deep well and the second deep well are respectively formed in the first high-pressure well and the second high-pressure well; The first well region and the second well region are respectively formed in the first deep well and the second deep well; The first active region and the second active region are respectively formed in the first well region and the second well region; wherein, the first deep well, the first well region and the first active region are ring structures, and the second deep well, the second well region and the second active region are eye-shaped structures; The third deep well, the fourth deep well, the fifth deep well, and the sixth deep well; wherein the third deep well is located between the first high-pressure well and the second high-pressure well, and the fourth deep well, the fifth deep well, and the sixth deep well are respectively located within the three hole structures of the second high-pressure well; The third well region, the fourth well region, the fifth well region, and the sixth well region are respectively formed in the third deep well, the fourth deep well, the fifth deep well, and the sixth deep well; The third active region, the fourth active region, the fifth active region, and the sixth active region are respectively formed in the third well region, the fourth well region, the fifth well region, and the sixth well region; A seventh well region formed outside the first high-voltage well and a seventh active region formed within the seventh well region; wherein the seventh well region, the seventh active region, the third deep well, the fourth deep well, the fifth deep well, the sixth deep well, the third well region, the fourth well region, the fifth well region, the sixth well region, the third active region, the fourth active region, the fifth active region, the sixth active region, the substrate, and the epitaxial layer have the same doping type, and are opposite to the doping type of the first high-voltage well, the second high-voltage well, the first deep well, the second deep well, the first well region, the second well region, the first active region, the second active region, and the buried layer.

2. The ESD protection device as described in claim 1, characterized in that, Both the first high-pressure trap and the second high-pressure trap are in contact with the buried layer; The first active region and the second active region are connected to the intermediate node metal electrode via a metal connecting line.

3. The ESD protection device as described in claim 2, characterized in that, The third active region is connected to the intermediate node metal electrode via a metal connecting line; The seventh active region is connected to the first metal electrode; The fourth active region and the sixth active region are connected to the first metal electrode via a metal connecting wire; The fifth active region is connected to the second metal electrode.

4. The ESD protection device as described in claim 3, characterized in that, The ESD protection device also includes: A first resistor is connected between the first metal electrode and the intermediate node metal electrode.

5. The ESD protection device as described in claim 3 or 4, characterized in that, The ESD protection device also includes: The second resistor is connected between the second metal electrode and the intermediate node metal electrode.

6. The ESD protection device as described in claim 4, characterized in that, The first resistor is an on-chip integrated resistor or an off-chip discrete resistor.

7. The ESD protection device according to any one of claims 1-4, characterized in that, The seventh well region, the seventh active region, the third deep well, the fourth deep well, the fifth deep well, the sixth deep well, the third well region, the fourth well region, the fifth well region, the sixth well region, the third active region, the fourth active region, the fifth active region, the sixth active region, the substrate, and the epitaxial layer are P-type doped; The first high-voltage well, the second high-voltage well, the first deep well, the second deep well, the first well region, the second well region, the first active region, the second active region, and the buried layer are N-type doped.

8. A method for preparing an ESD protection device resistant to positive and negative high voltages, characterized in that, The preparation method includes: Forming a first buried layer in the substrate, and forming an epitaxial layer on the substrate and the first buried layer. Forming a first high-voltage well and a second high-voltage well in the epitaxial layer that are in contact with the buried layer. Among them, the first high-voltage well is a ring structure, the second high-voltage well is a rectangular structure with a hole in the middle, the outer side of the first high-voltage well is aligned with the outer side of the buried layer, and the second high-voltage well is formed inside the first high-voltage well; Forming a first deep well and a second deep well in the first high-voltage well and the second high-voltage well respectively, and forming a first well region and a second well region in the first deep well and the second deep well respectively; Forming a first active region and a second active region in the first well region and the second well region respectively. Among them, the first deep well, the first well region, and the first active region are ring structures, and the second deep well, the second well region, and the second active region are rectangular structures with a hole in the middle; Forming a third deep well, a fourth deep well, a fifth deep well, and a sixth deep well in the epitaxial layer. Among them, the third deep well is located between the first high-voltage well and the second high-voltage well, and the fourth deep well, the fifth deep well, and the sixth deep well are respectively located in the three hole structures of the second high-voltage well; Forming a third well region, a fourth well region, a fifth well region, and a sixth well region in the third deep well, the fourth deep well, the fifth deep well, and the sixth deep well respectively, and forming a seventh well region outside the first high-voltage well; Forming a third active region, a fourth active region, a fifth active region, a sixth active region, and a seventh active region in the third well region, the fourth well region, the fifth well region, the sixth well region, and the seventh well region respectively. Among them, the doping types of the seventh well region, the seventh active region, the third deep well, the fourth deep well, the fifth deep well, the sixth deep well, the third well region, the fourth well region, the fifth well region, the sixth well region, the third active region, the fourth active region, the fifth active region, the sixth active region, the substrate, and the epitaxial layer are the same, and are opposite to the doping types of the first high-voltage well, the second high-voltage well, the first deep well, the second deep well, the first well region, the second well region, the first active region, the second active region, and the buried layer.

9. The preparation method according to claim 8, characterized in that, The seventh well region, the seventh active region, the third deep well, the fourth deep well, the fifth deep well, the sixth deep well, the third well region, the fourth well region, the fifth well region, the sixth well region, the third active region, the fourth active region, the fifth active region, the sixth active region, the first high-pressure well, the second high-pressure well, the first deep well, the second deep well, the first well region, the second well region, the first active region, the second active region, and the buried layer are formed by ion implantation or diffusion.

10. An electronic device, characterized in that, The electronic device includes the ESD protection device as described in any one of claims 1-7; or includes the ESD protection device prepared by the preparation method as described in claim 8 or 9.

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