CN115602676A - High-maintenance high-failure bidirectional silicon controlled rectifier electrostatic protection device and manufacturing method thereof - Google Patents
High-maintenance high-failure bidirectional silicon controlled rectifier electrostatic protection device and manufacturing method thereof Download PDFInfo
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- 230000002457 bidirectional effect Effects 0.000 title claims abstract description 20
- 238000012423 maintenance Methods 0.000 title claims abstract description 16
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 12
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title abstract description 6
- 229910052710 silicon Inorganic materials 0.000 title abstract description 6
- 239000010703 silicon Substances 0.000 title abstract description 6
- 238000002347 injection Methods 0.000 claims abstract description 167
- 239000007924 injection Substances 0.000 claims abstract description 167
- 239000000758 substrate Substances 0.000 claims abstract description 30
- 238000002955 isolation Methods 0.000 claims description 88
- 238000002513 implantation Methods 0.000 claims description 25
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 24
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 17
- 229910052760 oxygen Inorganic materials 0.000 claims description 17
- 239000001301 oxygen Substances 0.000 claims description 17
- 229910052581 Si3N4 Inorganic materials 0.000 claims description 12
- 239000000377 silicon dioxide Substances 0.000 claims description 12
- 235000012239 silicon dioxide Nutrition 0.000 claims description 12
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims description 12
- 239000007943 implant Substances 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 9
- 238000000151 deposition Methods 0.000 claims description 8
- 229920002120 photoresistant polymer Polymers 0.000 claims description 8
- 238000005530 etching Methods 0.000 claims description 4
- 238000005498 polishing Methods 0.000 claims description 4
- 238000004528 spin coating Methods 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims description 4
- 238000000137 annealing Methods 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 3
- 230000005012 migration Effects 0.000 claims description 3
- 238000013508 migration Methods 0.000 claims description 3
- 230000003071 parasitic effect Effects 0.000 description 12
- 230000015556 catabolic process Effects 0.000 description 10
- 238000010586 diagram Methods 0.000 description 4
- 230000003321 amplification Effects 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 230000005611 electricity Effects 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
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- H01L27/02—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers
- H01L27/0203—Particular design considerations for integrated circuits
- H01L27/0248—Particular design considerations for integrated circuits for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection
- H01L27/0251—Particular design considerations for integrated circuits for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection for MOS devices
- H01L27/0259—Particular design considerations for integrated circuits for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection for MOS devices using bipolar transistors as protective elements
- H01L27/0262—Particular design considerations for integrated circuits for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection for MOS devices using bipolar transistors as protective elements including a PNP transistor and a NPN transistor, wherein each of said transistors has its base coupled to the collector of the other transistor, e.g. silicon controlled rectifier [SCR] devices
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- H—ELECTRICITY
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- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/70—Manufacture or treatment of devices consisting of a plurality of solid state components formed in or on a common substrate or of parts thereof; Manufacture of integrated circuit devices or of parts thereof
- H01L21/77—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate
- H01L21/78—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices
- H01L21/82—Manufacture or treatment of devices consisting of a plurality of solid state components or integrated circuits formed in, or on, a common substrate with subsequent division of the substrate into plural individual devices to produce devices, e.g. integrated circuits, each consisting of a plurality of components
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- H01L27/02—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers
- H01L27/0203—Particular design considerations for integrated circuits
- H01L27/0248—Particular design considerations for integrated circuits for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection
- H01L27/0251—Particular design considerations for integrated circuits for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection for MOS devices
- H01L27/0296—Particular design considerations for integrated circuits for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection for MOS devices involving a specific disposition of the protective devices
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Abstract
The embodiment of the invention provides a high-maintenance high-failure bidirectional controllable silicon electrostatic protection device and a manufacturing method thereof, wherein a P-type substrate, an N-type buried layer, a first N-type deep well, a second N-type deep well and a third N-type deep well are arranged on the P-type substrate; a third P + injection region is arranged on the left side of the second N-type deep well, and a fourth P + injection region is arranged on the right side of the second N-type deep well; the left side of the second N-type deep well is provided with a first P well, and the right side of the second N-type deep well is provided with a second P well; a first P-type drift region and a second P-type drift region are arranged in the first P well, and a third P-type drift region and a fourth P-type drift region are arranged in the second P well; a first P + injection region is arranged in the first P-type drift region, and a first N + injection region is arranged in the second P-type drift region; a second N + injection region is arranged in the third P-type drift region, and a sixth P + injection region is arranged in the fourth P-type drift region; the first N + injection region, the first P + injection region and the second P + injection region are connected together to serve as an anode of the device, and the second N + injection region, the fifth P + injection region and the sixth P + injection region are connected together to serve as a cathode of the device.
Description
Technical Field
The invention relates to the field of electrostatic protection, in particular to a high-maintenance high-failure bidirectional thyristor electrostatic protection device and a manufacturing method thereof.
Background
With the progress of semiconductor manufacturing processes, the failure of integrated circuit chips and electronic products caused by ESD is becoming more serious. ESD protection of electronic products and integrated circuit chips has become one of the major challenges facing product engineers.
The modes of failure caused by ESD are hard failure, soft failure and potential failure respectively. The causes of these failures can be classified as electrical failures and thermal failures. The thermal failure means that when an ESD pulse comes, a current of several amperes to several tens of amperes is generated locally on the chip, the duration is short, but a large amount of heat is generated, so that local metal wires are melted or a chip is hot-spotted, and secondary breakdown is caused. Electrical failure means that the voltage applied to the gate oxide layer creates an electric field with a strength greater than the dielectric strength, causing a surface breakdown or dielectric breakdown. Because the threat of ESD to chips is getting more and more serious, the research on its physical mechanism is getting more and more attention.
Compared with other ESD devices, the traditional silicon controlled device has a double-conductance modulation mechanism, high unit area discharge efficiency, small unit parasitic capacitance and best robustness. However, since the trigger voltage is high, the latch-up is easily caused by the low holding voltage, and the design is important. The bidirectional thyristor device is improved on the basis of the traditional thyristor, can be considered as the integration of some anti-parallel connected common thyristors, has the same working principle as the traditional unidirectional thyristor, and can clamp the voltage in positive and negative directions respectively.
The cross-sectional view of the conventional triac electrostatic protection device is shown in fig. 1, and the equivalent circuit diagram thereof is shown in fig. 2. When the ESD pulse is applied to the anode of the bidirectional SCR, the N-type deep well and the third P + injection region form a reverse bias PN node. When the pulse voltage is higher than the avalanche breakdown voltage of the PN junction, a large amount of avalanche current is generated in the device, and the current flow path is to flow to the other end, namely the cathode, through the second P-well parasitic resistor. When the voltage across the parasitic well resistor is higher than the forward conduction voltage of the cb junction (formed by the second P-well and the second N-implant) of the NPN transistor, the transistor turns on. After the triode is switched on, base current is provided for the transverse PNP triode, and after the transverse PNP triode is also switched on, base current is also provided for the longitudinal NPN triode, so that a positive feedback loop is formed. Therefore, even if there is no avalanche current after the switching, the transistor can discharge static electricity. The bidirectional SCR is of a symmetrical structure, and when an ESD pulse occurs at the cathode, PN junction avalanche breakdown is generated between the N-type deep well and the second P + injection region, so that the PNP triode and the NPN triode are sequentially conducted to discharge static electricity. However, the SCR has a high trigger voltage and a low holding voltage, which easily exceed the design window and easily cause latch-up, so that it is required to increase the holding voltage. However, the method of increasing the sustain voltage may reduce the robustness of the device, and therefore, the robustness of the device needs to be considered.
Disclosure of Invention
The invention provides a high-maintenance high-failure bidirectional controllable silicon electrostatic protection device with a simple structure and a manufacturing method thereof.
In order to achieve the above purpose, the technical solution of the embodiment of the present invention is implemented as follows:
the embodiment of the invention provides a high-maintenance high-failure bidirectional thyristor electrostatic protection device, which comprises: a P-type substrate;
an N-type buried layer is arranged in the P-type substrate;
a first N-type deep well, a second N-type deep well and a third N-type deep well are arranged above the N-type buried layer;
a third P + injection region is arranged on the left side of the second N-type deep well;
a fourth P + injection region is arranged on the right side of the second N-type deep well;
a first P well is arranged on the left side of the second N-type deep well, and a second P well is arranged on the right side of the second N-type deep well;
a first P-type drift region and a second P-type drift region are arranged in the first P well, and a third P-type drift region and a fourth P-type drift region are arranged in the second P well;
a first P + injection region is arranged in the first P type drift region, and a first N + injection region is arranged in the second P type drift region;
a second N + injection region is arranged in the third P-type drift region, and a sixth P + injection region is arranged in the fourth P-type drift region;
the first N + injection region, the first P + injection region and the second P + injection region are connected together and used as an anode of the device, and the second N + injection region, the fifth P + injection region and the sixth P + injection region are connected together and used as a cathode of the device.
Wherein, the left side in first P + injection district with be equipped with first field oxygen isolation region between the P type substrate left side edge, the right side in first P + injection district with be equipped with second field oxygen isolation region between the second P + injection district left side, the right side in second P + injection district with be equipped with third field oxygen isolation region between the first N + injection district left side, the right side in first N + injection district with be equipped with fourth field oxygen isolation region between the left side in third P + injection district, the right side in third P + injection district with be equipped with fifth field oxygen isolation region between the left side in fourth P + injection district, the right side in fourth P + injection district with be equipped with sixth field oxygen isolation region between the left side in second N + injection district, the right side in second N + injection district with be equipped with seventh field oxygen isolation region between the left side in fifth P + injection district, the right side in fifth P + injection district with be equipped with eighth field oxygen isolation region between the left side in sixth P + injection district, the right side in sixth P + injection district with the ninth field oxygen isolation region between the P edge.
The left part of the first field oxide isolation region is positioned on the surface of the P-type substrate, and the right part of the first field oxide isolation region is positioned on the surface of the first P-type drift region; the left part of the second field oxide isolation region is positioned on the surface of the first P-type drift region, and the right part of the second field oxide isolation region is positioned on the surface of the first P well; the left part of the third field oxygen isolation region is positioned on the surface of the first P well, and the right part of the third field oxygen isolation region is positioned on the surface of the second P-type drift region; the left part of the fourth field oxide isolation region is positioned on the surface of the second P-type drift region, and the right part of the fourth field oxide isolation region is positioned on the surface of the first P well; the left part of the fifth field oxygen isolation region is positioned on the surface of the N-type deep well; the left part of the sixth field oxygen isolation region is positioned on the surface of the second P well, and the right part of the sixth field oxygen isolation region is positioned on the surface of the third P-type drift region; the left part of the seventh field oxide isolation region is positioned on the surface of the third P-type drift region, and the right part of the seventh field oxide isolation region is positioned on the surface of the second P well; the left part of the eighth field oxide isolation region is positioned on the surface of the second P well, and the right part of the eighth field oxide isolation region is positioned on the surface of the fourth P-type drift region; the left part of the ninth field oxide isolation region is positioned on the surface of the fourth P-type drift region, and the right part of the ninth field oxide isolation region is positioned on the surface of the P-type substrate.
When the high-voltage ESD pulse reaches the anode of the device and the cathode of the device is connected with a low potential, the second N + injection region, the third P-type drift region/the second P-well and the N-type buried layer form a longitudinal NPN type triode, the first P-well, the N-type deep well and the second P-well form a transverse PNP type triode structure, and the first P + injection region/the first P-type drift region/the first P-well, the N-type buried layer, the second P-well/the fourth P-type drift region/the sixth P + injection region form a transverse PNP type triode structure.
The embodiment of the invention also comprises a manufacturing method of the high-maintenance high-failure bidirectional triode thyristor electrostatic protection device, which is characterized by comprising the following steps:
the method comprises the following steps: forming an N-type buried layer in a P-type substrate;
step two: generating a P well above the N-type buried layer;
step three: generating three N-type deep wells in the P well, and generating a first P well and a second P well;
step four: generating a first P-type drift region and a second P-type drift region in the first P well;
step five: generating a third P-type drift region and a fourth P-type drift region in the second P well;
step six: forming a first P + injection region in the first P-type drift region, forming a second P + injection region in a first P well on the right side of the first P-type drift region, forming a first N + injection region in the second P-type drift region, forming a third P + injection region at the junction of the first P well and a second deep N well, forming a fourth P + injection region at the junction of the second deep N well and the second P well, forming a second N + injection region in the third P-type drift region, forming a fifth P + injection region in a second P well on the right side of the third P-type drift region, and forming a sixth P + injection region in the fourth P-type drift region;
step seven: forming a field oxide isolation region between all the implants, forming a first field oxide isolation region between the left side of the first P + injection region and the left side edge of the P-type substrate, and forming a ninth field oxide isolation region between the right side of the sixth P + injection region and the right side edge of the P-type substrate;
step eight: annealing all the injection regions to eliminate the migration of impurities in the injection regions;
step nine: and connecting the first N + injection region, the first P + injection region and the second P + injection region together to be used as an anode of the device, and connecting the second N + injection region, the fifth P + injection region and the sixth P + injection region together to be used as a cathode of the device.
Wherein, still include before the said method:
growing a silicon dioxide film on a P-type substrate, and then depositing a silicon nitride film; spin-coating a photoresist layer on a wafer, and adding a mask plate to expose and develop the wafer to form an isolation shallow slot; and etching the silicon dioxide, the silicon nitride and the isolation shallow groove, removing the photoresist layer, depositing a layer of silicon dioxide, and then performing chemical mechanical polishing until the silicon nitride layer is removed.
The embodiment of the invention provides a high-maintenance high-failure bidirectional thyristor electrostatic protection device and a manufacturing method thereof, and the high-maintenance high-failure bidirectional thyristor electrostatic protection device has the following beneficial effects:
1. according to the invention, because the first P-type drift region exists, the anode current flows through the first P-type drift region and the first P well through the first P + injection region to reach the N-type buried layer, the parasitic resistance of the N-type buried layer flows through the current, so that the transverse PNP formed by the first P + injection region, the first P-type drift region, the first P well, the N-type buried layer, the second P well, the third P-type drift region and the second N + injection region is started and discharges the current, the current in the device is uniformly distributed, and the existence of the first P-type drift region enables the second discharge path which is difficult to be started originally to be realized.
2. In the invention, the breakdown surface is converted into the N-type deep well and the P + injection region from the original N-type deep well and P well due to the existence of the third P + injection region and the fourth P + injection region, so that the trigger voltage of the device is reduced; the second and third P-type drift regions improve the concentration of a P well where the N + injection region is located, so that the concentration of a base electrode of an emitter of the parasitic NPN triode is increased, the injection efficiency of the emitter is reduced, and the holding voltage is improved.
3. According to the invention, the distance D3 between the first N + injection region and the second P + injection region and the distance D1 between the second N + injection region and the fourth P + injection region are adjustable, when the distance D1 is increased, the base region width of the longitudinal NPN type triode is also increased, the amplification factor of the longitudinal NPN type triode is reduced, and the maintaining voltage is increased.
Drawings
FIG. 1 is a cross-sectional view of a conventional bidirectional SCR electrostatic protection device;
FIG. 2 is an equivalent circuit diagram of a conventional bidirectional SCR ESD protection device;
FIG. 3 is a cross-sectional view of a high-sustain, high-failure triac ESD protection device in accordance with an embodiment of the present invention;
fig. 4 is an equivalent circuit diagram of a high-sustain high-failure triac electrostatic protection device according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
As shown in fig. 3, a high-maintenance high-failure triac electrostatic protection device includes a P-type substrate 101; an N-type buried layer 201 is arranged in the substrate; an N-type deep well 301, an N-type deep well 302 and an N-type deep well 303 are arranged above the N-type buried layer 201; a first P well 401 is arranged between the N-type deep well 301 and the N-type deep well 302, and a second P well 402 is arranged between the N-type deep well 301 and the N-type deep well 303; a second P + injection region 602, a first P-type drift region 501 and a second P-type drift region 502 are arranged in the first P well 401; a second P + injection region 607, a third P-type drift region 503 and a fourth P-type drift region 504 are arranged in the second P well 402; a first P + injection region 601 is arranged in the first P-type drift region 501, a first N + injection region 603 is arranged in the second P-type drift region 502, a first N + injection region 606 is arranged in the third P-type drift region 503, and a first P + injection region 608 is arranged in the fourth P-type drift region 504; a third P + injection region 604 is arranged at the junction of the first P well 401 and the second N-type deep well 302, and a fourth P + injection region 605 is arranged at the junction of the second P well 401 and the second N-type deep well 302; the first P + injection region 601, the second P + injection region 602, and the first N + injection region 603 are connected together and serve as an anode of the device; the second N + implant region 606, the fifth P + implant region 607, and the sixth P + implant region 608 are connected together and serve as the cathode of the device.
A first field oxide isolation region 701 is arranged between the left side of the first P + injection region 601 and the left side edge of the P-type substrate 101, a second field oxide isolation region 702 is arranged between the right side of the first P + injection region 601 and the left side of the second P + injection region 602, a third field oxide isolation region 703 is arranged between the right side of the second P + injection region 602 and the left side of the first N + injection region 603, a fourth field oxide isolation region 704 is arranged between the right side of the first N + injection region 603 and the left side of the third P + injection region 604, a fifth field oxide isolation region 705 is arranged between the right side of the third P + injection region 604 and the left side of the fourth P + injection region 605, a sixth field oxide isolation region 706 is arranged between the right side of the fourth P + injection region 605 and the left side of the second N + injection region 606, a seventh field oxide isolation region 707 is arranged between the right side of the second N + injection region 606 and the left side of the fifth P + injection region 607, an eighth field oxide isolation region 709 is arranged between the right side of the fifth P + injection region 607 and the left side edge of the sixth P + injection region 608, and a ninth field oxide isolation region 709 is arranged between the right side edge P + injection region 101 and the sixth P + injection region 608.
The left part of the first field oxide isolation region 701 is positioned on the surface of the P-type substrate 101, and the right part of the first field oxide isolation region is positioned on the surface of the first P-type drift region 501; the left part of the second field oxide isolation region 702 is located on the surface of the first P-type drift region 501, and the right part of the second field oxide isolation region is located on the surface of the first P-well 401; the left part of the third field oxide isolation region 703 is located on the surface of the first P well 401, and the right part is located on the surface of the second P-type drift region 502; the left part of the fourth field oxide isolation region 704 is located on the surface of the second P-type drift region 502, and the right part is located on the surface of the first P-well 401; the left part of the fifth field oxide isolation region 705 is positioned on the surface of the N-type deep well 302; the left part of the sixth field oxide isolation region 706 is located on the surface of the second P well 402, and the right part is located on the surface of the third P-type drift region 503; the left part of the seventh field oxide isolation region 707 is located on the surface of the third P-type drift region 503, and the right part is located on the surface of the second P-well 402; the left part of the eighth field oxide isolation region 708 is located on the surface of the second P well 402, and the right part is located on the surface of the fourth P-type drift region 504; the left part of the ninth field oxide isolation region 709 is located on the surface of the fourth P-type drift region 504, and the right part is located on the surface of the P-type substrate 101;
as shown in fig. 4, when the high-voltage ESD pulse reaches the anode of the device and the cathode of the device is connected to the low potential, the first N + injection region 603, the second P-type drift region 502, the first P-well 401 and the N-type deep well 301 form a vertical NPN transistor, the first P-well 401, the N-type deep well 302 and the second P-well 402 form a lateral PNP transistor structure, and the first P + injection region 601, the first P-type drift region 501, the first P-well 401, the N-type buried layer 201, the second P-well 402, the fourth P-type drift region 504 and the sixth P + injection region form a lateral PNP transistor structure.
When the ESD high voltage pulse reaches the anode of the device, the first P + injection region 601, the second P + injection region 602, and the first N + injection region 603 are at a high potential, the second N + injection region 606, the fifth P + injection region 607, and the sixth P + injection region 608 at the other end are at a low potential, the N-type deep well 302 and the fourth P + injection region 605 are reversely biased, when the pulse voltage is higher than the avalanche breakdown voltage of the junction, a large amount of avalanche current is generated inside the device, the avalanche current flows through the parasitic resistance of the second P well 402 and flows into the cathode, as can be seen from the equivalent circuit diagram 4, the NPN current increases the voltage at both ends of the parasitic resistance in the second P well 402, so that the longitudinal triode is turned on first, after the NPN tube is turned on, a large amount of current is injected into the N-type buried layer 201, the current injection increases the voltage at both ends of the parasitic resistance of the N-type buried layer 201, so that the lateral PNP tube is triggered, and the lateral NPN tube and the longitudinal NPN tube form a positive feedback, thereby forming a first current path; after the first current path is formed, due to the existence of the first P-type drift region 501, the anode current flows through the first P + injection region 601, the first P-type drift region 501 and the first P well 401 to reach the N-type buried layer, the parasitic resistance of the N-type buried layer 201 flows through the current, so that the lateral PNP formed by the first P + injection region 601/the first P-type drift region 501/the first P well 401, the N-type buried layer 201, the second P well 402/the third P-type drift region 503/the second N + injection region 606 is turned on and discharges the current, and the current in the device is uniformly distributed, and the existence of the first P-type drift region 501 enables the second discharge path which is difficult to be turned on originally to be realized.
When the ESD high voltage pulse reaches the anode of the device, the existence of the fourth P + injection region 605 enables the breakdown surface to be converted from the original N-type deep well 302 and P well 402 into the N-type deep well 302 and the fourth P + injection region 605, thereby reducing the trigger voltage of the device; the existence of the second P-type drift region 502 improves the concentration of the first P well 401 where the first N + injection region 603 is located, so that the base concentration of the emitter of the parasitic NPN triode is increased, the injection efficiency of the emitter is reduced, and the sustain voltage is improved.
When the ESD high voltage pulse reaches the anode of the device, the distance D1 between the second N + injection region 606 and the fourth P + injection region 605 of the device is adjustable, and when D1 is increased, the base region width of the longitudinal NPN type triode is also increased, thereby reducing the amplification factor of the longitudinal NPN type triode and increasing the holding voltage.
A manufacturing method of a bidirectional triode thyristor electrostatic protection device with high maintenance and high failure comprises the following steps:
the method comprises the following steps: growing a silicon dioxide film on a P-type substrate 101, and then depositing a silicon nitride film; spin-coating a photoresist layer on a wafer, and adding a mask plate to expose and develop the wafer to form an isolation shallow slot; etching silicon dioxide, silicon nitride and shallow isolating slot, removing photoresist layer, depositing a layer of silicon dioxide, chemical polishing until silicon nitride layer is removed
Step two: forming an N-type buried layer 201 in a P-type substrate 101;
step three: generating a P well above the N-type buried layer 201;
step four: three N-type deep wells 301, 302 and 303 are generated in the P well, and a first P well 401 and a second P well 402 are generated;
step five: a first P-type drift region 501 and a second P-type drift region 502 are generated in the first P-well 401;
step six: a third P-type drift region 503 and a fourth P-type drift region 504 are generated in the second P-well 402;
step seven: forming a first P + injection region 601 in the first P-type drift region 501, forming a second P + injection region 602 in the first P-well 401 on the right side of the first P-type drift region 501, forming a first N + injection region 603 in the second P-type drift region 502, forming a third P + injection region 604 at the boundary between the first P-well 401 and the second deep N-well 302, forming a fourth P + injection region 605 at the boundary between the second deep N-well 302 and the second P-well 402, forming a second N + injection region 606 in the third P-type drift region 503, forming a fifth P + injection region 607 in the second P-well 402 on the right side of the third P-type drift region 503, and forming a sixth P + injection region 608 in the fourth P-type drift region 504;
step eight: forming field oxide isolation regions between all the implants, forming a first field oxide isolation region 701 between the left side of the first P + implant region 601 and the left side edge of the P-type substrate 101, and forming a ninth field oxide isolation region 709 between the right side of the sixth P + implant region 608 and the right side edge of the P-type substrate 101;
step nine: annealing all the injection regions to eliminate the migration of impurities in the injection regions;
step ten: the first N + implantation region 603, the first P + implantation region 601, and the second P + implantation region 602 are connected together and serve as an anode of the device, and the second N + implantation region 606, the fifth P + implantation region 607, and the sixth P + implantation region 608 are connected together and serve as a cathode of the device.
Optionally, the method further comprises:
growing a silicon dioxide film on a P-type substrate 101, and then depositing a silicon nitride film; spin-coating a photoresist layer on a wafer, and adding a mask plate to expose and develop the wafer to form an isolation shallow slot; and etching the silicon dioxide, the silicon nitride and the isolation shallow groove, removing the photoresist layer, depositing a layer of silicon dioxide, and then performing chemical mechanical polishing until the silicon nitride layer is removed.
The manufacturing method of the bidirectional controllable silicon electrostatic protection device with high maintenance and high failure is simple in process and convenient to operate. According to the manufactured bidirectional thyristor electrostatic protection device structure, the P + injection region is added and is wrapped by the P + injection region through the P-type drift region to guide current to go downwards, a current path is increased, current of a main path is shared, and failure current of the device is improved; meanwhile, a P + injection region is added on a breakdown plane to change the breakdown voltage, so that the trigger voltage of the device is reduced; the emitter of the parasitic NPN tube of the device is wrapped by the P-type drift region to increase the base region concentration of the parasitic triode and reduce the efficiency of the emitter, so that the maintaining voltage of the device is improved, meanwhile, the D1 distance of the device is adjustable, the base region width of the longitudinal NPN triode is increased when the D1 is increased, the amplification factor of the longitudinal NPN triode is reduced, the maintaining voltage is increased, and the device can be applied to an ESD protection design, so that an internal chip is effectively protected, and the risk of latch lock is avoided. The device of the embodiment of the invention adopts a BCDMOS process with the thickness of 0.25 mu m.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.
Claims (6)
1. A high-maintenance high-failure bidirectional thyristor electrostatic protection device is characterized by comprising: a P-type substrate;
an N-type buried layer is arranged in the P-type substrate;
a first N-type deep well, a second N-type deep well and a third N-type deep well are arranged above the N-type buried layer;
a third P + injection region is arranged on the left side of the second N-type deep well;
a fourth P + injection region is arranged on the right side of the second N-type deep well;
a first P well is arranged on the left side of the second N-type deep well, and a second P well is arranged on the right side of the second N-type deep well;
a first P-type drift region and a second P-type drift region are arranged in the first P well, and a third P-type drift region and a fourth P-type drift region are arranged in the second P well;
a first P + injection region is arranged in the first P-type drift region, and a first N + injection region is arranged in the second P-type drift region;
a second N + injection region is arranged in the third P-type drift region, and a sixth P + injection region is arranged in the fourth P-type drift region;
the first N + injection region, the first P + injection region and the second P + injection region are connected together and used as an anode of the device, and the second N + injection region, the fifth P + injection region and the sixth P + injection region are connected together and used as a cathode of the device.
2. The device according to claim 1, wherein a first field oxide isolation region is disposed between a left side of the first P + implantation region and a left side edge of the P-type substrate, a second field oxide isolation region is disposed between a right side of the first P + implantation region and a left side of the second P + implantation region, a third field oxide isolation region is disposed between a right side of the second P + implantation region and a left side of the first N + implantation region, a fourth field oxide isolation region is disposed between a right side of the first N + implantation region and a left side of the third P + implantation region, a fifth field oxide isolation region is disposed between a right side of the third P + implantation region and a left side of the fourth P + implantation region, a sixth field oxide isolation region is disposed between a right side of the fourth P + implantation region and a left side of the second N + implantation region, a seventh field oxide isolation region is disposed between a right side of the second N + implantation region and a left side of the fifth P + implantation region, a ninth field oxide isolation region is disposed between a right side of the fifth P + implantation region and a left side edge of the sixth P + implantation region, and a ninth field oxide isolation region is disposed between a right side of the fifth P + implantation region and a left side of the fifth P + implantation region.
3. The high-maintenance high-failure triac electrostatic protection device of claim 1, wherein a left portion of said first field oxide isolation region is located on a surface of said P-type substrate, and a right portion of said first field oxide isolation region is located on a surface of said first P-type drift region; the left part of the second field oxide isolation region is positioned on the surface of the first P-type drift region, and the right part of the second field oxide isolation region is positioned on the surface of the first P well; the left part of the third field oxide isolation region is positioned on the surface of the first P well, and the right part of the third field oxide isolation region is positioned on the surface of the second P-type drift region; the left part of the fourth field oxygen isolation region is positioned on the surface of the second P-type drift region, and the right part of the fourth field oxygen isolation region is positioned on the surface of the first P well; the left part of the fifth field oxygen isolation region is positioned on the surface of the N-type deep well; the left part of the sixth field oxide isolation region is positioned on the surface of the second P well, and the right part of the sixth field oxide isolation region is positioned on the surface of the third P-type drift region; the left part of the seventh field oxide isolation region is positioned on the surface of the third P-type drift region, and the right part of the seventh field oxide isolation region is positioned on the surface of the second P well; the left part of the eighth field oxide isolation region is positioned on the surface of the second P well, and the right part of the eighth field oxide isolation region is positioned on the surface of the fourth P-type drift region; the left part of the ninth field oxide isolation region is positioned on the surface of the fourth P-type drift region, and the right part of the ninth field oxide isolation region is positioned on the surface of the P-type substrate.
4. The high-sustain-voltage triac electrostatic protection device of claim 1, wherein when the high-voltage ESD pulse reaches the anode of the device and the cathode of the device is connected to the low potential, the second N + injection region, the third P-type drift region/second P-well and the N-type buried layer form a vertical NPN transistor, the first P-well, the N-type deep well and the second P-well form a lateral PNP triode structure, and the first P + injection region/the first P-type drift region/the first P-well, the N-type buried layer, the second P-well/the fourth P-type drift region/the sixth P + injection region form a lateral PNP triode structure.
5. A manufacturing method of a high-maintenance high-failure bidirectional triode thyristor electrostatic protection device is characterized by comprising the following steps:
the method comprises the following steps: forming an N-type buried layer in a P-type substrate;
step two: generating a P well above the N-type buried layer;
step three: generating three N-type deep wells in the P well, and generating a first P well and a second P well;
step four: generating a first P-type drift region and a second P-type drift region in the first P well;
step five: generating a third P-type drift region and a fourth P-type drift region in the second P well;
step six: forming a first P + injection region in the first P-type drift region, forming a second P + injection region in a first P well on the right side of the first P-type drift region, forming a first N + injection region in the second P-type drift region, forming a third P + injection region at the junction of the first P well and a second deep N well, forming a fourth P + injection region at the junction of the second deep N well and the second P well, forming a second N + injection region in the third P-type drift region, forming a fifth P + injection region in a second P well on the right side of the third P-type drift region, and forming a sixth P + injection region in the fourth P-type drift region;
step seven: forming a field oxide isolation region between all the implants, forming a first field oxide isolation region between the left side of the first P + implantation region and the left side edge of the P-type substrate, and forming a ninth field oxide isolation region between the right side of the sixth P + implantation region and the right side edge of the P-type substrate;
step eight: annealing all the injection regions to eliminate the migration of impurities in the injection regions;
step nine: and connecting the first N + injection region, the first P + injection region and the second P + injection region together to be used as an anode of the device, and connecting the second N + injection region, the fifth P + injection region and the sixth P + injection region together to be used as a cathode of the device.
6. The method for manufacturing the high-maintenance high-failure bidirectional triode thyristor electrostatic discharge protection device according to claim 5, further comprising the following steps:
growing a silicon dioxide film on a P-type substrate, and then depositing a silicon nitride film; spin-coating a photoresist layer on a wafer, and adding a mask plate to expose and develop the wafer to form an isolation shallow slot; and etching the silicon dioxide, the silicon nitride and the isolation shallow groove, removing the photoresist layer, depositing a layer of silicon dioxide, and then performing chemical mechanical polishing until the silicon nitride layer is removed.
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