TW202203413A - Electrostatic discharge protection device and circuit - Google Patents

Abstract

An electrostatic discharge protection device including a substrate, a first PNP element, a second PNP element and an isolation region. The substrate has a P-type conductivity. The first and second PNP elements are formed in the substrate. The isolation region isolates the first and second PNP elements.

Description

Electrostatic discharge protection device and circuit

The present invention relates to an electrostatic discharge protection device, in particular to an electrostatic discharge protection device with series-connected PNP elements.

Component damage caused by electrostatic discharge has become one of the most important reliability issues for integrated circuit products. In particular, as the size continues to shrink to the depth of sub-micron, the gate oxide layer of the metal oxide semiconductor is getting thinner and thinner, and the integrated circuit is more likely to be damaged by the phenomenon of electrostatic discharge. In general industry standards, the I/O pins of integrated circuit products must be able to pass the human body model electrostatic discharge test above 2000 volts and the mechanical model electrostatic discharge test above 200 volts. Therefore, in integrated circuit products, ESD protection components must be arranged near all the input and output pads to protect the internal core circuits from ESD currents.

An embodiment of the present invention provides an electrostatic discharge protection device including a substrate, a first PNP element, a second PNP element, and an isolation region. The substrate has a P-type conductivity. The first PNP element includes a first well region, a first doping region and a second doping region. The first well region is formed in the substrate and has an N-type conductivity. The first doped region is formed in the first well region and has P-type conductivity. The second doped region is formed in the first well region and has P-type conductivity. The second PNP element includes a second well region, a third doping region and a fourth doping region. The second well region is formed in the substrate and has N-type conductivity. The third doped region is formed in the second well region and has P-type conductivity. The fourth doped region is formed in the second well region and has P-type conductivity. An isolation region is formed in the substrate and separates the first PNP element and the second PNP element.

In order to make the objects, features and advantages of the present invention more obvious and easy to understand, the following specific embodiments are given and described in detail in conjunction with the accompanying drawings. The present specification provides different embodiments to illustrate the technical features of different embodiments of the present invention. Wherein, the configuration of each element in the embodiment is for illustration, and not for limiting the present invention. In addition, parts of the reference numerals in the drawings in the embodiments are repeated for the purpose of simplifying the description, and do not mean the correlation between different embodiments.

FIG. 1 is a schematic diagram of the electrostatic discharge protection device of the present invention. As shown, the ESD protection device 100 includes a substrate 110 , PNP elements 120 and 130 . The substrate 110 has P-type conductivity. In a possible embodiment, the base 110 may be a semiconductor substrate, such as a silicon substrate. In addition, the above-mentioned semiconductor substrate can also be an elemental semiconductor, including germanium; compound semiconductors, including silicon carbide, gallium arsenide, gallium phosphide, and indium phosphide ), indium arsenide and/or indium antimonide; alloy semiconductors, including silicon germanium (SiGe), gallium arsenide phosphorous (GaAsP), aluminum indium arsenide (AlInAs), aluminum arsenic gallium Alloy (AlGaAs), Gallium Indium Arsenide (GaInAs), Gallium Indium Phosphate (GaInP) and/or Gallium Indium Arsenide Phosphorus (GaInAsP) or a combination of the above materials. In addition, the substrate 110 may also be a semiconductor on insulator. In one embodiment, the substrate 110 may be an undoped substrate. However, in other embodiments, the substrate 110 can also be a lightly doped substrate, such as a lightly doped P-type substrate.

The PNP device 120 includes a well region 121 , doped regions 122 and 123 . The well region 121 is formed in the substrate 110 and has N-type conductivity. The present invention does not limit how the well region 121 is formed. In one possible embodiment, the well region 121 may be formed by an ion implantation step. For example, phosphorus ions or arsenic ions are implanted in the region where the well region 121 is to be formed to form the well region 121 . In other embodiments, the well 121 is a high voltage N well (HVNW).

The doped regions 122 and 123 are formed in the well region 121 and have P-type conductivity. In this embodiment, the impurity concentrations of the doped regions 122 and 123 are higher than the impurity concentration of the substrate 110 . In a possible embodiment, P+ type doped regions 122 and 123 are formed by implanting P type impurities. P-type impurities include impurities such as boron, gallium, aluminum, indium, or a combination thereof. In a possible embodiment, the doped region 122 serves as a collector of the PNP element 120 , the doped region 123 serves as an emitter of the PNP element 120 , and the well region 121 serves as a base of the PNP element 120 (base).

In other embodiments, the PNP device 120 further includes a doped region 124 , and isolation regions 125 and 126 . The doped regions 124 have N-type conductivity and serve as electrical contacts for the well regions 121 . In this embodiment, the impurity concentration of the impurity region 124 is higher than that of the well region 121 . In a possible embodiment, the N+ type doped region 124 is formed by implanting N type impurities. In some embodiments, the doped regions 122-124 are formed by performing an implantation step in conjunction with a patterned mask (not shown).

Isolation regions 125 and 126 are formed on the surface of the substrate 110 and extend into the well region 121 . In this embodiment, the isolation region 125 is located between the doped regions 122 and 123 for separating the doped regions 122 and 123 . The isolation region 126 is located between the doped regions 123 and 124 for separating the doped regions 123 and 124 . In some embodiments, isolation regions 125 and 126 may be field oxides (FOX). In some embodiments, the isolation regions 125 and 126 may be local oxidation of silicon (LOCOS) or shallow trench isolation (STI) structures. In other embodiments, the isolation regions 125 and 126 may be made of silicon oxide, silicon nitride, silicon oxynitride, other suitable dielectric materials, or a combination thereof.

The PNP device 130 at least includes a well region 131 , doped regions 132 and 133 . The well region 131 is formed in the substrate 110 and has N-type conductivity. Since the characteristics of the well area 131 are similar to those of the well area 121, the details are omitted. In this embodiment, the well area 131 does not contact the well area 121 . In some embodiments, the impurity concentration of the well region 131 is similar to the impurity concentration of the well region 121, but is not intended to limit the present invention. In other embodiments, the impurity concentration of the well region 131 may be lower or higher than the impurity concentration of the well region 121 . For example, one of the wells 121 and 131 is a high pressure N-type well, and the other is a general well. In this example, the impurity concentration of the high-voltage N-type well region is lower than that of the general well region. Therefore, the high-voltage N-type well region can withstand higher voltages.

Doped regions 132 and 133 are formed in the well region 131 . The doped regions 132 and 133 have P-type conductivity. In this embodiment, the impurity concentrations of the doped regions 132 and 133 are higher than the impurity concentration of the substrate 110 . In a possible embodiment, the impurity concentrations of the doped regions 132 and 133 are similar to the impurity concentrations of the doped regions 122 and 123 . Since the characteristics of the doped regions 132 and 133 are similar to those of the doped regions 122 and 123 , they will not be described again. In a possible embodiment, the doped region 132 serves as a collector of the PNP element 130 , the doped region 133 serves as an emitter of the PNP element 130 , and the well region 131 serves as a base of the PNP element 130 .

In other embodiments, the PNP device 130 further includes a doped region 134 and isolation regions 135 and 136 . The doped regions 134 have N-type conductivity and serve as electrical contacts for the well regions 131 . In this embodiment, the impurity concentration of the impurity region 134 is higher than that of the well region 131 and is similar to the impurity concentration of the impurity region 124 . Since the characteristics of the doped region 134 are similar to those of the doped region 124, the details are not repeated here.

Isolation regions 135 and 136 are formed on the surface of the substrate 110 and extend into the well region 131 . In this embodiment, the isolation region 135 is located between the doped regions 132 and 133 for separating the doped regions 132 and 133 . The isolation region 136 is located between the doped regions 133 and 134 for separating the doped regions 133 and 134 . Since the characteristics of the isolation regions 135 and 136 are similar to the characteristics of the isolation regions 125 and 126 , detailed descriptions are omitted.

In this embodiment, the ESD protection device 100 further includes an isolation region 152 . The isolation region 152 is formed on the surface of the substrate 110 and extends into the well regions 121 and 131 . The isolation region 152 is used to separate the PNP devices 120 and 130 . In this example, isolation region 152 is located between doped regions 124 and 132 . In a possible embodiment, isolation region 152 is in direct contact with doped regions 124 and 132 .

In other embodiments, the ESD protection device 100 further includes a doped region 140 . The doped region 140 is formed in the substrate 110 and has P-type conductivity. In a possible embodiment, the impurity concentration of the doped region 140 is similar to the impurity concentration of the doped region 122 . Since the characteristics of the doped region 140 are similar to those of the doped region 122, the details are omitted. In this embodiment, the doped region 140 serves as an electrical contact point for the substrate 110 .

In some embodiments, the ESD protection device 100 further includes isolation regions 151 and 153 . The isolation region 151 is formed on the surface of the substrate 110 and extends into the well region 121 and the substrate 110 . In this embodiment, the isolation region 151 is used to separate the doped region 140 and the PNP device 120 . In addition, the isolation region 153 is formed on the surface of the substrate 110 and extends into the well region 131 and the substrate 110 . The isolation region 153 is used to separate the PNP device 130 from other devices (not shown).

The present invention does not limit the size of the isolation regions 151 to 153 . In a possible embodiment, the width (horizontal direction) of the isolation region 152 is larger than the widths of the isolation regions 151 and 153 . For example, the distance between doped regions 124 and 132 is greater than the distance between doped regions 140 and 122 . The distance between doped regions 124 and 132 is also greater than the distance between doped region 134 and another doped region (not shown). In other embodiments, the widths of the isolation regions 125 , 126 , 135 and 136 are smaller than the width of the isolation region 151 . In this example, isolation regions 125, 126, 135, and 136 are similar in width.

In a possible embodiment, the electrostatic discharge protection device 100 further includes wirings 161 - 163 . The traces 161 are electrically connected to the doped regions 140 and 122 . In a possible embodiment, the trace 161 is coupled to a voltage source VL. The traces 162 are electrically connected to the doped regions 123 , 124 and 132 . The traces 163 are electrically connected to the doped regions 133 and 134 . In a possible embodiment, the trace 163 is coupled to a voltage source VH. Under normal operation (no ESD events), the voltage source VH is used to receive a high operating voltage, and the voltage source VL may receive a low operating voltage, such as a ground voltage.

When an electrostatic discharge event occurs at the voltage source VH and the voltage source VL is grounded, the PNP elements 130 and 120 are turned on in sequence. Therefore, an electrostatic discharge current flows from the voltage source VH through the doped region 133 , the well region 131 , the doped region 132 , the doped region 123 , the well region 121 , and the doped region 122 into the voltage source VL. At this time, since the voltage of the well region 131 rises, a current flows into the substrate 110 , so that the voltage of the substrate 110 rises, thereby turning on an NPN element with a P-type substrate between the PNP elements 130 and 120 . In this example, the well regions 131, 121 and the substrate 110 constitute a P-type substrate NPN device. The well region 131 serves as the collector of the NPN element with the P-type substrate, the well region 121 serves as the emitter of the NPN element with the P-type substrate, and the substrate 110 serves as the base of the NPN element with the P-type substrate. Since the NPN element having the P-type substrate is turned on, the resistance of the on-resistance of the PNP elements 130 and 120 can be reduced. Therefore, the ESD protection device 100 can withstand a higher current and increase the holding voltage of the ESD protection device 100 to prevent the ESD protection device 100 from being latched up (with no ESD event) during normal operation (no ESD event). latch up). In addition, the NPN element with the P-type substrate may be a parasitic element, or an NPN element generated by doping, and the present invention is not limited thereto.

FIG. 2 is a schematic diagram of an equivalent circuit of the electrostatic discharge protection device of FIG. 1 . As shown, the ESD protection device 100 includes PNP elements 120 and 130 and an NPN element 200 having a P-type substrate. The emitter E1 of the PNP element 120 is the doped region 123 in FIG. 1 . The collector C1 of the PNP element 120 is the doped region 122 in FIG. 1 . The base B1 of the PNP element 120 is the well 121 in FIG. 1 . In this embodiment, a resistor R121 is provided between the emitter E1 and the base B1 of the PNP element 120 . In this example, the resistance R121 is the equivalent resistance of the well region 121 . In addition, the collector C1 of the PNP element 120 is electrically connected to the voltage source VL through a wire (such as the wire 161 in FIG. 1 ).

The emitter E2 of the PNP element 130 is the doped region 133 in FIG. 1 . The collector C2 of the PNP element 130 is the doped region 132 in FIG. 1 . The base B2 of the PNP element 130 is the well 131 in FIG. 1 . In this embodiment, there is a resistor R131 between the emitter E2 and the base B2 of the PNP element 130 . In this example, the resistance R131 is the equivalent resistance of the well region 131 . In addition, the collector C2 of the PNP element 130 is electrically connected to the emitter E1 of the PNP element 120 through a wire (such as the wire 162 in FIG. 1 ). The emitter E2 of the PNP element 130 is electrically connected to the voltage source VH through a trace (such as the trace 163 in FIG. 1 ).

Since the well region 121 in FIG. 1 serves as the emitter E3 of the NPN element 200 with the P-type substrate, it can be considered that the emitter E3 of the NPN element 200 with the P-type substrate is electrically connected to the base B1 of the PNP element 120 . In addition, since the well region 131 in FIG. 1 serves as the collector C3 of the NPN element 200 with the P-type base, it can be considered that the collector C3 of the NPN element 200 with the P-type base is electrically connected to the base B2 of the PNP element 130 . In this embodiment, there is a resistor R110 between the base electrode B3 of the NPN element 200 having the P-type substrate and the voltage source VL. In this example, the resistor R110 is the equivalent resistance of the substrate 110 .

When an electrostatic discharge event occurs at the voltage source VH and the voltage source VL is grounded, the PNP element 130 is turned on because the voltage of the emitter E2 of the PNP element 130 rises. At this time, since the voltage of the emitter E1 of the PNP element 120 rises, the PNP element 120 is then turned on. Therefore, an electrostatic discharge current flows from the voltage source VH, through the PNP elements 130 and 120, into the voltage source VL. At this time, since the PNP elements 130 and 120 are turned on, the NPN element 200 with the P-type substrate is also turned on, thereby reducing the equivalent impedance when the PNP elements 130 and 120 are turned on, so that the electrostatic discharge protection device 100 has a higher sustaining voltage .

FIG. 3 is another schematic diagram of the electrostatic discharge protection device of the present invention. FIG. 3 is similar to FIG. 1 , except that the electrostatic discharge protection device 300 of FIG. 3 further includes a PNP element 170 . The PNP device 170 includes a well region 171 , doped regions 172 and 173 . The well region 171 is formed in the substrate 110 and has N-type conductivity. Since the characteristics of the well area 171 are similar to those of the well area 121, the details are omitted. In this embodiment, the isolation region 153 separates the well regions 131 and 171 . In some embodiments, the impurity concentrations of the well regions 121 , 131 and 171 are all the same, but are not intended to limit the present invention. In other embodiments, the impurity concentration of one of the well regions 121 , 131 and 171 may be lower or higher than the impurity concentration of the other of the well regions 121 , 131 and 171 . For example, one of the wells 121, 131 and 171 is a high pressure N-type well, while the other of the wells 121, 131 and 171 is not a high pressure N-type.

Doped regions 172 and 173 are formed in the well region 171 . The doped regions 172 and 173 have P-type conductivity. In this embodiment, the impurity concentrations of the doped regions 172 and 173 are higher than the impurity concentration of the substrate 110 . In a possible embodiment, the impurity concentrations of the doped regions 172 and 173 are similar to the impurity concentrations of the doped regions 122 and 123 . Since the properties of the doped regions 172 and 173 are similar to those of the doped regions 122 and 123 , they are not described again. In this embodiment, the doped region 172 serves as a collector of the PNP element 170 , the doped region 173 serves as an emitter of the PNP element 170 , and the well region 171 serves as a base of the PNP element 170 .

In other embodiments, the PNP device 170 further includes a doped region 174 and isolation regions 175 and 176 . The doped region 174 is formed in the well region 171 and has N-type conductivity. In a possible embodiment, the impurity concentration of the doped region 174 is similar to the impurity concentration of the doped region 124 . Since the characteristics of the doped region 174 are similar to those of the doped region 124, the details are not repeated here. In this embodiment, the doped region 174 serves as an electrical contact point for the well region 171 .

Isolation regions 175 and 176 are formed on the surface of the substrate 110 and extend into the well region 171 . In this embodiment, the isolation region 175 is located between the doped regions 172 and 173 for separating the doped regions 172 and 173 . The isolation region 176 is located between the doped regions 173 and 174 for separating the doped regions 173 and 174 . Since the characteristics of the isolation regions 175 and 176 are similar to the characteristics of the isolation regions 125 and 126 , detailed descriptions are omitted.

In this embodiment, the isolation region 153 is used to separate the PNP elements 130 and 170 . In this example, isolation region 153 is located between doped regions 134 and 172 . In a possible embodiment, isolation region 153 is in direct contact with doped regions 134 and 172 . In other embodiments, the ESD protection device 300 further includes an isolation region 154 . The isolation region 154 is formed on the surface of the substrate 110 and extends into the well region 171 and the substrate 110 . Isolation region 154 is used to separate PNP device 170 from other devices (not shown). The present invention does not limit the size of the isolation regions 151 to 154 . In a possible embodiment, the width of the isolation region 154 is similar to the width of the isolation region 151 . In other embodiments, the widths of isolation regions 152 and 153 are similar and larger than the widths of isolation regions 151 and 154 . In this example, the widths of isolation regions 125 , 126 , 135 , 136 , 175 and 176 are similar and smaller than the width of isolation region 151 .

In a possible embodiment, the ESD protection device 300 further includes a wiring 164 . The trace 164 is electrically connected to the doped regions 173 and 174 and is coupled to the voltage source VH. In addition, the traces 163 are electrically connected to the doped regions 133 , 134 and 172 . In this embodiment, the traces 161 to 164 are used to connect the PNP elements 120 , 130 and 170 in series. When more PNP elements are connected in series, the trigger voltage of the ESD protection device 300 is higher, so that the ESD protection device 300 can be prevented from being triggered during normal operation (ie, no ESD event). The present invention does not limit the number of PNP elements. In other embodiments, the ESD protection device 300 has more PNP elements.

When an electrostatic discharge event occurs at the voltage source VH and the voltage source VL is coupled to ground, the PNP elements 170 , 130 and 120 are turned on in sequence. Therefore, an electrostatic discharge current flows into the voltage source VL through the PNP elements 170 , 130 and 120 . In this embodiment, a first NPN element with a P-type substrate is arranged between the PNP elements 170 and 130 , a second NPN element with a P-type substrate is arranged between the PNP elements 130 and 120 , and the one between the PNP elements 170 and 120 is There is a third NPN element with a P-type substrate in between. In this example, when the PNP elements 170 , 130 and 120 are turned on, the first NPN element with a P-type substrate between the PNP elements 170 and 130 and the third NPN element with a P-type substrate between the PNP elements 170 and 120 The NPN element will also conduct.

In this embodiment, the first NPN element having a P-type substrate is composed of well regions 171 and 131 and the substrate 110 . The well region 171 serves as the collector of the first NPN element with a P-type substrate, the well region 131 serves as the emitter of the first NPN element with a P-type substrate, and the substrate 110 serves as the base of the first NPN element with a P-type substrate. In addition, the second NPN element with a P-type substrate is composed of the well regions 131 and 121 and the substrate 110 . In this example, the well region 131 serves as the collector of the second NPN element with a P-type substrate, the well region 121 serves as the emitter of the second NPN element with a P-type substrate, and the substrate 110 serves as the second NPN element with a P-type substrate. the base of the element. The third NPN device with a P-type substrate is composed of well regions 171 and 121 and the substrate 110 . In this example, the well region 171 serves as the collector of the third NPN element with a P-type substrate, the well region 121 serves as the emitter of the third NPN element with a P-type substrate, and the substrate 110 serves as the third NPN element with a P-type substrate. the base of the element.

When the PNP elements 170, 130 and 120 are turned on, the first NPN element with a P-type base reduces the equivalent impedance of the PNP elements 170 and 130 when they are turned on, and the third NPN element with a P-type base reduces the conduction of the PNP elements 170 and 120 Equivalent impedance when . Therefore, the ESD protection device 300 has a higher sustain voltage and can withstand a higher current.

FIG. 4 is a schematic diagram of an equivalent circuit of the electrostatic discharge protection device 300 of FIG. 3 . As shown, the ESD protection device 300 includes PNP elements 120, 130, 170 and NPN elements 200, 400, 500 having a P-type substrate. Since the characteristics of the PNP elements 120 and 130 and the NPN element 200 with a P-type substrate are the same as those of the PNP elements 120 and 130 and the NPN element 200 with a P-type substrate in FIG.

In this embodiment, the emitter E4 of the PNP element 170 is the doped region 173 in FIG. 3 . The collector C4 of the PNP element 170 is the doped region 172 in FIG. 3 . The base B4 of the PNP element 170 is the well 171 in FIG. 3 . In this embodiment, a resistor R171 is provided between the emitter E4 and the base B4 of the PNP element 170 . In this example, the resistance R171 is the equivalent resistance of the well region 171 . In addition, the collector C4 of the PNP element 170 is electrically connected to the emitter E2 of the PNP element 130 through a wire (such as the wire 163 in FIG. 3 ). The emitter E4 of the PNP element 170 is electrically connected to the voltage source VH through a trace (such as the trace 164 in FIG. 3 ).

Since the well region 131 in FIG. 3 serves as the emitter E5 of the NPN element 400 with the P-type substrate, it can be considered that the emitter E5 of the NPN element 400 with the P-type substrate is electrically connected to the base B2 of the PNP element 130 . In addition, the well region 171 in FIG. 3 serves as the collector C5 of the NPN element 400 with the P-type substrate, so it can be considered that the collector C5 of the NPN element 400 with the P-type substrate is electrically connected to the base B4 of the PNP element 170 . In this embodiment, there is a resistor R110B between the base B5 of the NPN element 400 having the P-type substrate and the voltage source VL. In this example, the resistor R110B is the equivalent resistance of the substrate 110 .

Since the well region 121 in FIG. 3 serves as the emitter E6 of the NPN element 500 with the P-type substrate, it can be considered that the emitter E6 of the NPN element 500 with the P-type substrate is electrically connected to the base B1 of the PNP element 120 . In addition, the well region 171 in FIG. 3 serves as the collector C6 of the NPN element 500 with the P-type substrate, so it can be considered that the collector C6 of the NPN element 500 with the P-type substrate is electrically connected to the base B4 of the PNP element 170 . In this embodiment, there is a resistor R110C between the base B6 of the NPN element 500 having the P-type substrate and the voltage source VL. In this example, the resistor R110C is the equivalent resistance of the substrate 110 .

In the present embodiment, since the distance between the NPN elements 400 and 500 having the P-type substrate and the voltage source VL is greater than the distance between the NPN element 200 having the P-type substrate and the voltage source VL, the impedances of the resistors R110B and R110C are higher than that of the resistor R110A resistance is large. In one embodiment, the resistance of the resistors R110A, R110B and R110C can be controlled by adjusting the concentration of the substrate 110 . In a preferred embodiment, the voltages of the resistors R110B and R110C are less than about 0.7V so that the NPN devices 400 and 500 with the P-type substrate are turned on.

When an electrostatic discharge event occurs at the voltage source VH and the voltage source VL is grounded, the PNP element 170 is turned on because the voltage at the emitter E4 of the PNP element 170 rises. At this time, since the voltage of the emitter E2 of the PNP element 130 rises, the PNP element 130 is then turned on. Since the voltage of the emitter E1 of the PNP element 120 rises, the PNP element 120 is also turned on. Therefore, an electrostatic discharge current flows from the voltage source VH, through the PNP elements 170, 130 and 120, into the voltage source VL. At this time, since the PNP elements 170, 130 and 120 are turned on, the NPN elements 400 and 500 with the P-type substrate are also turned on, thereby reducing the equivalent impedance when the PNP elements 170, 130 and 120 are turned on, and making the electrostatic discharge protection device 300 has a higher sustain voltage.

FIGS. 5A-5C are the manufacturing method of the electrostatic discharge protection apparatus 100 of FIG. 1. FIG. First, referring to FIG. 5A, a substrate 110 is provided. In one possible embodiment, the substrate 110 may include a silicon-on-insulator (SOI) substrate, a bulk silicon (Bulk silicon) substrate, or a silicon-on-substrate epitaxial layer. In this embodiment, the substrate 110 has P-type conductivity.

Next, isolation regions 151 to 153 are formed in the substrate 110 to define the positions of the PNP elements 120 and 130 , and the isolation regions 125 , 126 , 135 and 136 are formed. In this embodiment, the isolation regions 151 ˜ 153 , 125 , 126 , 135 and 136 are taken as an example of a field oxide layer, but are not intended to limit the present invention. In other embodiments, other isolation structures, such as shallow trench isolation structures, may also be used. In a possible embodiment, the size of the isolation region 152 is larger than the size of the isolation regions 151 and 153 . In this example, the size of the isolation regions 151 and 153 is larger than the size of the isolation regions 125 , 126 , 135 and 136 . The sizes of the isolation regions 125, 126, 135 and 136 are similar to each other.

Referring to FIG. 5B , well regions 121 and 131 are formed in the substrate 110 . Well area 121 is located between isolation areas 151 and 152 , and well area 131 is located between isolation areas 152 and 153 . In this embodiment, the isolation region 152 separates the well regions 121 and 131 . In a possible embodiment, the well region 121 extends below the isolation regions 151 and 152 . Therefore, isolation regions 151 and 152 cover portions of well region 121 . Likewise, well region 131 extends below isolation regions 152 and 153 . Accordingly, isolation regions 152 and 153 cover portions of well region 131 . In this embodiment, the well regions 121 and 131 have N-type conductivity.

Next, referring to FIG. 5C , doped regions 140 are formed in the substrate 110 , doped regions 122 and 123 are formed in the well region 120 , and doped regions 132 and 133 are formed in the well region 130 . In one embodiment, the doped regions 140 , 122 , 123 , 132 and 133 may be formed by implanting P-type impurities. P-type impurities include impurities such as boron, gallium, aluminum, indium, or a combination thereof. The doping concentration may be determined by process technology and device characteristics, and is not limited herein. In this embodiment, the doping concentration of the doped regions 140 , 122 , 123 , 132 and 133 is higher than that of the substrate 110 . In one embodiment, the doped regions 140, 122, 123, 132, and 133 are formed by performing an implantation step in conjunction with a patterned mask (not shown). In this embodiment, the doped region 122 is located between the isolation regions 151 and 125 . The doped region 123 is located between the isolation regions 125 and 126 . Doped region 132 is located between isolation regions 152 and 135 . Doped region 133 is located between isolation regions 135 and 136 .

Next, a doped region 124 is formed in the well region 120 , and a doped region 134 is formed in the well region 130 . In one embodiment, the doped regions 124 and 134 may be formed by implanting N-type impurities. N-type impurities include, for example, phosphorus, arsenic, nitrogen, antimony, or a combination thereof. The doping concentration may be determined by process technology and device characteristics, and is not limited herein. In this embodiment, the doping concentrations of the doped regions 124 and 134 are higher than the doping concentrations of the well regions 121 and 131 . In one embodiment, doped regions 124 and 134 are formed by performing an implantation step in conjunction with a patterned mask (not shown). In this embodiment, the doped region 124 is located between the isolation regions 126 and 152 . Doped region 134 is located between isolation regions 136 and 153 .

The doped regions 122 , 123 and the well region 121 constitute the PNP device 120 , and the doped regions 132 , 133 and the well region 131 constitute the PNP device 130 . In addition, there is an NPN element with a P-type substrate between the PNP elements 120 and 130 . For example, the well regions 121, 131 and the substrate 110 constitute an NPN device. With the existence of the NPN elements, when the PNP elements 120 and 130 are turned on, the PNP elements 120 and 130 have a higher sustain voltage, and the on-resistance of the PNP elements 120 and 130 is optimized. Additionally, PNP elements 120 and 130 can withstand higher ESD currents.

Unless otherwise defined, all terms (including technical and scientific terms) herein are commonly understood by those of ordinary skill in the art to which this invention belongs. Furthermore, unless expressly stated otherwise, the definitions of words in general dictionaries should be construed as consistent with their meanings in articles in the related technical field, and should not be construed as ideal states or overly formal voices.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. . For example, the system, apparatus, or method described in the embodiments of the present invention may be implemented in a physical embodiment of hardware, software, or a combination of hardware and software. Therefore, the protection scope of the present invention should be determined by the scope of the appended patent application.

100, 300: Electrostatic discharge protection device 110: Base 120, 130, 170: PNP elements 121, 131, 171: Well area 122~124, 132~134, 140, 172~174: Doping region 151~154, 125, 126, 135, 136, 175, 176: Quarantine 161~164: Route VH, VL: voltage source R121, R131, R110, R110A, R110B, R110C: Resistors 200, 400, 500: NPN elements

FIG. 1 is a schematic diagram of the electrostatic discharge protection device of the present invention. FIG. 2 is a schematic diagram of an equivalent circuit of the electrostatic discharge protection device of FIG. 1 . FIG. 3 is another schematic diagram of the electrostatic discharge protection device of the present invention. FIG. 4 is a schematic diagram of an equivalent circuit of the electrostatic discharge protection device of FIG. 3 . 5A to 5C are schematic diagrams of the manufacturing method of the electrostatic discharge protection device of the present invention.

100: Electrostatic discharge protection device

110: Base

120, 130: PNP element

121, 131: Well area

122~124, 132~134, 140: Doping region

151~153, 125, 126, 135, 136: Quarantine

161~163: Route

VH, VL: voltage source

Claims (17)

An electrostatic discharge protection device, comprising: a substrate having a P-type conductivity; A first PNP element comprising: a first well region formed in the substrate and having an N-type conductivity; a first doped region formed in the first well region and having the P-type conductivity; a second doped region formed in the first well region and having the P-type conductivity; A second PNP element comprising: a second well region formed in the substrate and having the N-type conductivity; a third doped region formed in the second well region and having the P-type conductivity; a fourth doped region formed in the second well region and having the P-type conductivity; and A first isolation region is formed in the substrate and separates the first PNP element and the second PNP element. The electrostatic discharge protection device of claim 1, wherein the first PNP element further comprises: a fifth doped region formed in the first well region and having the N-type conductivity; a second isolation region formed in the first well region between the first and second doped regions; and A third isolation region is formed in the first well region and located between the second and fifth doped regions. The electrostatic discharge protection device of claim 2, wherein the second PNP element further comprises: a sixth doped region formed in the second well region and having the N-type conductivity; a fourth isolation region formed in the second well region between the third and fourth doped regions; and A fifth isolation region is formed in the second well region and located between the fourth and sixth doped regions. The ESD protection device of claim 3, wherein the first isolation region extends into the first and second well regions and is located between the third and fifth doped regions. The electrostatic discharge protection device of claim 3, wherein the width of the first isolation region is greater than the width of the second isolation region. Such as the electrostatic discharge protection device of claim 1, further including: a seventh doped region formed in the substrate and having the P-type conductivity; a first trace electrically connecting the first and seventh doped regions; a second trace electrically connected to the second, third and fifth doped regions; and A third wiring is electrically connected to the fourth and sixth doping regions. The electrostatic discharge protection device of claim 1, wherein the impurity concentration of the first well region is different from the impurity concentration of the second well region. Such as the electrostatic discharge protection device of claim 1, further including: A third PNP element comprising: a third well region formed in the substrate and having the N-type conductivity; an eighth doping region formed in the third well region and having the P-type conductivity; a ninth doped region formed in the third well region and having the P-type conductivity; a tenth doped region formed in the third well region and having the N-type conductivity; a sixth isolation region formed in the third well region and located between the eighth and ninth doped regions; a seventh isolation region formed in the third well region and located between the ninth and tenth doped regions; and an eighth isolation region formed in the substrate and extending into the second and third well regions; Wherein the eighth isolation region is located between the sixth and eighth doping regions. The electrostatic discharge protection device of claim 6, wherein an impurity concentration of one of the first, second and third well regions is different from an impurity concentration of the other of the first, second and third well regions. As claimed in claim 6, the electrostatic discharge protection device further includes: a seventh doped region formed in the substrate and having the P-type conductivity; a first trace electrically connecting the first and seventh doped regions; a second trace electrically connected to the second, third and fifth doped regions; a third trace electrically connected to the fourth, sixth and eighth doped regions; and A fourth wire is electrically connected to the ninth and tenth doped regions. An electrostatic discharge protection circuit, comprising: a first PNP element, having a first collector, a first emitter and a first base, the first emitter is coupled to a first voltage source; A second PNP element has a second collector, a second emitter and a second base, the second collector is coupled to the first emitter, the second emitter is coupled to a second voltage source ;as well as A first NPN element has a third collector, a third emitter and a third base, the third collector is coupled to the second base, the third emitter is coupled to the first base , the third base is coupled to the first power line. The electrostatic discharge protection circuit of claim 11, wherein when an electrostatic discharge event occurs at the second voltage source and the first voltage source is grounded, the first PNP element and the second PNP element are turned on in sequence. The electrostatic discharge protection circuit of claim 12, wherein when an electrostatic discharge event occurs at the second voltage source and the first voltage source is grounded, the first NPN element is turned on for reducing the first PNP element and the second voltage source. The on-resistance of the two PNP components. The electrostatic discharge protection circuit of claim 11, wherein there is a first equivalent impedance between the first emitter and the first base, and a second equivalent impedance between the second emitter and the second base effective impedance, and there is a third equivalent impedance between the third base and the first voltage source. Such as the electrostatic discharge protection circuit of claim 14, further including: A third PNP element has a fourth collector, a fourth emitter and a fourth base, the fourth collector is coupled to the second emitter, the fourth emitter is coupled to the second voltage source ; A second NPN element has a fifth collector, a fifth emitter and a fifth base, the fifth collector is coupled to the fourth base, and the fifth emitter is coupled to the second base , the fifth base is coupled to the first voltage source; and A third NPN element has a sixth collector, a sixth emitter and a sixth base, the sixth collector is coupled to the second voltage source, and the sixth emitter is coupled to the first base , the sixth base is coupled to the first voltage source. The electrostatic discharge protection circuit of claim 15, wherein when an electrostatic discharge event occurs at the second voltage source and the first voltage source is grounded, the first PNP element, the second PNP element and the third PNP element depend on sequence turn on. The electrostatic discharge protection circuit of claim 15, wherein there is a fourth equivalent impedance between the fourth base and the second voltage source, and a fifth and so on between the fifth base and the second voltage source effective impedance, and there is a sixth equivalent impedance between the sixth base and the second voltage source.

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