TWI732615B - 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 problems for integrated circuit products. Especially as the size continues to shrink to the depth of sub-micron level, the gate oxide layer of the MOS semiconductor is getting thinner and thinner, and the integrated circuit is more susceptible to damage due to 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 mode electrostatic discharge test above 200 volts. Therefore, in integrated circuit products, electrostatic discharge protection components must be installed near all input and output pads to protect the internal core circuit from electrostatic discharge current.

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

In order to make the purpose, features and advantages of the present invention more comprehensible, embodiments are specifically listed below, and detailed descriptions are made in conjunction with the accompanying drawings. The specification of the present invention provides different examples to illustrate the technical features of different embodiments of the present invention. Wherein, the configuration of each element in the embodiment is for illustrative purposes, and is not intended to limit the present invention. In addition, the part of the repetition of the symbols of the drawings in the embodiments is for simplifying the description, and does not imply the relevance between different embodiments.

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

The PNP device 120 includes a well region 121 and 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 to form the well area 121. In a 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 scheduled to be formed to form the well region 121. In other embodiments, the well area 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 concentration of the doped regions 122 and 123 is higher than the impurity concentration of the substrate 110. In one 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 device 120, the doped region 123 serves as an emitter of the PNP device 120, and the well region 121 serves as a base of the PNP device 120. (base).

In other embodiments, the PNP device 120 further includes a doped region 124 and isolation regions 125 and 126. The doped region 124 has N-type conductivity and serves as an electrical contact point of the well region 121. In this embodiment, the impurity concentration of the doped region 124 is higher than the impurity concentration of the well region 121. In one 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 a patterned mask (not shown) in cooperation with an implantation step.

The 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 to separate the doped regions 122 and 123. The isolation region 126 is located between the doped regions 123 and 124 to separate the doped regions 123 and 124. In some embodiments, the isolation regions 125 and 126 may be field oxide (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 material of the isolation regions 125 and 126 can be silicon oxide, silicon nitride, silicon oxynitride, other suitable dielectric materials, or a combination of the foregoing.

The PNP device 130 includes at least a well region 131 and 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 the characteristics of the well area 121, details are not described herein again. 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 it 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 well areas 121 and 131 is a high-pressure N-type well area, and the other is a general well area. In this example, the impurity concentration of the high-pressure N-type well is lower than the impurity concentration of the general well. Therefore, the high-pressure N-well area can withstand higher voltages.

The 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 concentration of the doped regions 132 and 133 is higher than the impurity concentration of the substrate 110. In a possible embodiment, the impurity concentration of the doped regions 132 and 133 is similar to the impurity concentration 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 device 130, the doped region 133 serves as an emitter of the PNP device 130, and the well region 131 serves as a base of the PNP device 130.

In other embodiments, the PNP device 130 further includes a doped region 134 and isolation regions 135 and 136. The doped region 134 has N-type conductivity and serves as an electrical contact point of the well region 131. In this embodiment, the impurity concentration of the doped region 134 is higher than the impurity concentration of the well region 131 and is similar to the impurity concentration of the doped region 124. Since the characteristics of the doped region 134 are similar to those of the doped region 124, it will not be repeated.

The 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 to separate the doped regions 132 and 133. The isolation region 136 is located between the doped regions 133 and 134 to separate the doped regions 133 and 134. Since the characteristics of the isolation regions 135 and 136 are similar to those of the isolation regions 125 and 126, they will not be described again.

In this embodiment, the electrostatic discharge 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, the isolation region 152 is located between the doped regions 124 and 132. In a possible embodiment, the isolation region 152 directly contacts the doped regions 124 and 132.

In other embodiments, the electrostatic discharge 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, details are not described herein again. In this embodiment, the doped region 140 serves as an electrical contact point of the substrate 110.

In some embodiments, the electrostatic discharge 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 greater than the width of the isolation regions 151 and 153. For example, the distance between the doped regions 124 and 132 is greater than the distance between the doped regions 140 and 122. The distance between the doped regions 124 and 132 is also greater than the distance between the doped region 134 and another doped region (not shown). In other embodiments, the width of the isolation regions 125, 126, 135, and 136 is smaller than the width of the isolation region 151. In this example, the widths of the isolation regions 125, 126, 135, and 136 are similar.

In a possible embodiment, the electrostatic discharge protection device 100 further includes wires 161 to 163. The wiring 161 electrically connects the doped regions 140 and 122. In one possible embodiment, the trace 161 is coupled to a voltage source VL. The wiring 162 is electrically connected to the doped regions 123, 124, and 132. The wiring 163 is electrically connected to the doped regions 133 and 134. In one possible embodiment, the wire 163 is coupled to a voltage source VH. Under normal operation (no electrostatic discharge event), 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 in 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, because the voltage of the well region 131 rises, a current flows into the substrate 110, which causes the voltage of the substrate 110 to rise, thereby turning on an NPN device with a P-type substrate between the PNP devices 130 and 120. In this example, the well regions 131 and 121 and the substrate 110 constitute an NPN device with a P-type substrate. The well region 131 serves as the collector of the NPN device with the P-type substrate, the well region 121 serves as the emitter of the NPN device with the P-type substrate, and the substrate 110 serves as the base of the NPN device with the P-type substrate. Since the NPN device with the P-type substrate is turned on, the impedance of the on-resistance of the PNP devices 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 under normal operation (no ESD event). latch up). In addition, the NPN element with a P-type substrate can be a parasitic element, or an NPN element produced by doping, and the present invention is not limited thereto.

Figure 2 is a schematic diagram of the equivalent circuit of the ESD protection device shown in Figure 1. As shown in the figure, the electrostatic discharge protection device 100 includes PNP elements 120 and 130 and an NPN element 200 with 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 device 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 area 121. In addition, the collector C1 of the PNP device 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 area 131. In addition, the collector C2 of the PNP device 130 is electrically connected to the emitter E1 of the PNP device 120 through a wire (such as the wire 162 in FIG. 1). The emitter E2 of the PNP device 130 is electrically connected to the voltage source VH through a wire (such as the wire 163 in FIG. 1).

Since the well area 121 in FIG. 1 serves as the emitter E3 of the NPN device 200 with a P-type substrate, it can be regarded that the emitter E3 of the NPN device 200 with a P-type substrate is electrically connected to the base B1 of the PNP device 120. In addition, since the well region 131 in FIG. 1 serves as the collector C3 of the NPN device 200 with a P-type substrate, it can be regarded that the collector C3 of the NPN device 200 with a P-type substrate is electrically connected to the base B2 of the PNP device 130. . In this embodiment, there is a resistor R110 between the base B3 of the NPN device 200 with a P-type substrate and the voltage source VL. In this example, the resistance 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, the voltage of the emitter E1 of the PNP element 120 rises, so the PNP element 120 is turned on. Therefore, an electrostatic discharge current flows from the voltage source VH through the PNP elements 130 and 120 to the voltage source VL. At this time, since the PNP elements 130 and 120 are turned on, the NPN element 200 with a P-type substrate is also turned on, thus reducing the equivalent impedance when the PNP elements 130 and 120 are turned on, so that the ESD protection device 100 has a higher sustaining voltage .

Figure 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 ESD protection device 300 of FIG. 3 further includes a PNP element 170. The PNP device 170 includes a well region 171 and 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, details are not repeated here. In this embodiment, the isolation area 153 separates the well areas 131 and 171. In some embodiments, the impurity concentrations of the well regions 121, 131, and 171 are all the same, but this is 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 well areas 121, 131, and 171 is a high-pressure N-type well area, and the other of the well areas 121, 131, and 171 is not a high-pressure N-type well area.

The 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 concentration of the doped regions 172 and 173 is higher than the impurity concentration of the substrate 110. In a possible embodiment, the impurity concentration of the doped regions 172 and 173 is similar to the impurity concentration of the doped regions 122 and 123. Since the characteristics of the doped regions 172 and 173 are similar to those of the doped regions 122 and 123, they will not be described again. In this embodiment, the doped region 172 serves as a collector of the PNP device 170, the doped region 173 serves as an emitter of the PNP device 170, and the well region 171 serves as a base of the PNP device 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, it will not be repeated here. In this embodiment, the doped region 174 serves as the electrical contact point of the well region 171.

The 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 to separate the doped regions 172 and 173. The isolation region 176 is located between the doped regions 173 and 174 to separate 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, they will not be described again.

In this embodiment, the isolation region 153 is used to separate the PNP devices 130 and 170. In this example, the isolation region 153 is located between the doped regions 134 and 172. In a possible embodiment, the isolation region 153 directly contacts the doped regions 134 and 172. In other embodiments, the electrostatic discharge 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. The isolation region 154 is used to separate the 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 the isolation regions 152 and 153 are similar and larger than the widths of the isolation regions 151 and 154. In this example, the widths of the isolation regions 125, 126, 135, 136, 175, and 176 are similar and smaller than the width of the isolation region 151.

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

When an electrostatic discharge event occurs in the voltage source VH and the voltage source VL is coupled to the 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, there is a first NPN device with a P-type substrate between the PNP devices 170 and 130, and a second NPN device with a P-type substrate is located between the PNP devices 130 and 120. Between the PNP devices 170 and 120 There is a third NPN device 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 with a P-type substrate between the PNP elements 170 and 120 The NPN element will also turn on.

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

When the PNP elements 170, 130, and 120 are turned on, the first NPN element with a P-type substrate reduces the equivalent impedance when the PNP elements 170 and 130 are turned on, and the third NPN element with a P-type substrate reduces the conduction of the PNP elements 170 and 120 The equivalent impedance at the time. Therefore, the ESD protection device 300 has a relatively high sustaining voltage and can withstand relatively large currents.

FIG. 4 is a schematic diagram of an equivalent circuit of the electrostatic discharge protection device 300 of FIG. 3. As shown in the figure, the electrostatic discharge protection device 300 includes PNP elements 120, 130, 170 and NPN elements 200, 400, 500 with a P-type substrate. Since the characteristics of the PNP devices 120 and 130 and the NPN device 200 with a P-type substrate are the same as those of the PNP devices 120 and 130 and the NPN device 200 with a P-type substrate in FIG. 2, they will not be repeated here.

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 171. In addition, the collector C4 of the PNP device 170 is electrically connected to the emitter E2 of the PNP device 130 through a wire (such as the wire 163 in FIG. 3). The emitter E4 of the PNP device 170 is electrically connected to the voltage source VH through a wire (such as the wire 164 in FIG. 3).

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

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

In this embodiment, since the distance between the NPN element 400 and 500 with a P-type substrate and the voltage source VL is longer than the distance between the NPN element 200 with a P-type substrate and the voltage source VL, the resistances of the resistors R110B and R110C are greater than the resistance of R110A. The impedance 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 voltage of the resistors R110B and R110C is less than about 0.7V so that the NPN devices 400 and 500 with a 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 of the emitter E4 of the PNP element 170 rises. At this time, the voltage of the emitter E2 of the PNP element 130 rises, so the PNP element 130 is 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 to 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 a P-type substrate are also turned on, thus reducing the equivalent impedance when the PNP elements 170, 130, and 120 are turned on, and enabling the electrostatic discharge protection device 300 has a higher sustaining voltage.

Figs. 5A to 5C show a method of manufacturing the electrostatic discharge protection device 100 of Fig. 1. First, please refer to FIG. 5A to provide a substrate 110. In one possible embodiment, the substrate 110 may include a silicon-on-insulating (SOI) substrate, a bulk silicon (Bulk silicon) substrate, or a silicon epitaxial layer on the substrate. 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 devices 120 and 130, and to form isolation regions 125, 126, 135, and 136. In this embodiment, the isolation regions 151 to 153, 125, 126, 135, and 136 are based on the field oxide layer as an example, but it is not intended to limit the present invention. In other embodiments, other isolation structures may also be used, such as shallow trench isolation structures. 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 sizes of the isolation regions 151 and 153 are larger than the sizes 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.

Please refer to FIG. 5B to form well regions 121 and 131 in the substrate 110. The well area 121 is located between the isolation areas 151 and 152, and the well area 131 is located between the isolation areas 152 and 153. In this embodiment, the isolation area 152 separates the well areas 121 and 131. In a possible embodiment, the well area 121 extends below the isolation areas 151 and 152. Therefore, the isolation regions 151 and 152 cover part of the well region 121. Similarly, the well region 131 extends below the isolation regions 152 and 153. Therefore, the isolation regions 152 and 153 cover part of the well region 131. In this embodiment, the well regions 121 and 131 have N-type conductivity.

Next, referring to FIG. 5C, a doped region 140 is 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 an 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 depends on the process technology and device characteristics, and is not limited here. In this embodiment, the doping concentration of the doped regions 140, 122, 123, 132, and 133 is higher than the doping concentration of the substrate 110. In one embodiment, the doped regions 140, 122, 123, 132, and 133 are formed by a patterned mask (not shown) in cooperation with an implantation step. 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. The doped region 132 is located between the isolation regions 152 and 135. The doped region 133 is located between the 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 can be formed by implanting N-type impurities. N-type impurities include impurities such as phosphorus, arsenic, nitrogen, antimony, or a combination thereof. The doping concentration depends on the process technology and device characteristics, and is not limited here. In this embodiment, the doping concentration of the doping regions 124 and 134 is higher than the doping concentration of the well regions 121 and 131. In one embodiment, the doped regions 124 and 134 are formed by a patterned mask (not shown) in cooperation with an implantation step. In this embodiment, the doped region 124 is located between the isolation regions 126 and 152. The doped region 134 is located between the isolation regions 136 and 153.

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

Unless otherwise defined, all vocabulary (including technical and scientific vocabulary) herein belong to the general understanding of persons with ordinary knowledge in the technical field of the present invention. In addition, unless expressly stated, the definition of a word in a general dictionary should be interpreted as consistent with the meaning in an article in its related technical field, and should not be interpreted as an ideal state or an overly formal voice.

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

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

Figure 1 is a schematic diagram of the electrostatic discharge protection device of the present invention. Figure 2 is a schematic diagram of the equivalent circuit of the ESD protection device shown in Figure 1. Figure 3 is another schematic diagram of the electrostatic discharge protection device of the present invention. Figure 4 is a schematic diagram of the equivalent circuit of the ESD protection device shown in Figure 3. Figures 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 components

121, 131: Well area

122~124, 132~134, 140: doped area

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

161~163: routing

VH, VL: voltage source

Claims (16)

An electrostatic discharge protection device includes: a substrate having a P-type conductivity; a first PNP element including: a first well region formed in the substrate and having an N-type conductivity; a first A doped region is formed in the first well region and has the P-type conductivity; a second doped region is formed in the first well region and has the P-type conductivity; a second The PNP device includes: 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 is formed in the second well region and has the P-type conductivity; and a first isolation region is formed in the substrate and separates the first PNP element and the second PNP device; wherein the first PNP device further includes: 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 And is located between the first and second doped regions; and a third isolation region is formed in the first well region and is located between the second and fifth doped regions. The electrostatic discharge protection device of claim 1, wherein the second PNP element further includes: a sixth doped region formed in the second well region and having the N-type conductivity; A fourth isolation region is formed in the second well region and is located between the third and fourth doped regions; and a fifth isolation region is formed in the second well region and is located in the Between the fourth and sixth doped regions. According to the electrostatic discharge protection device of claim 2, wherein the first isolation region extends into the first and second well regions and is located between the third and fifth doped regions. According to the electrostatic discharge protection device of claim 2, wherein the width of the first isolation region is greater than the width of the second isolation region. For example, the electrostatic discharge protection device of claim 1, further comprising: a seventh doped region formed in the substrate and having the P-type conductivity; and a first wiring electrically connected to the first and seventh Doped region; a second trace electrically connected to the second, third and fifth doped regions; and a third trace electrically connected to the fourth and sixth doped 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. For example, the electrostatic discharge protection device of claim 1, further comprising: a third PNP device, including: a third well region formed in the substrate and having the N-type conductivity; and an eighth doped 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; and 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 The isolation area is formed in the third well area and is located in the ninth and tenth dopants Between the miscellaneous 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 doped regions. The electrostatic discharge protection device of claim 5, wherein the impurity concentration of one of the first, second, and third well regions is different from the impurity concentration of the other of the first, second, and third well regions. For example, the electrostatic discharge protection device of claim 5, further comprising: a seventh doped region formed in the substrate and having the P-type conductivity; and a first wiring electrically connected to the first and seventh Doped region; 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 The fourth trace is electrically connected to the ninth and tenth doped regions. An electrostatic discharge protection circuit includes: 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 The device 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; and a first An NPN device 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 The third base is coupled to the first voltage source. Such as the electrostatic discharge protection circuit of claim 10, 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 sequentially turned on. For example, the electrostatic discharge protection circuit of claim 11, wherein when an electrostatic discharge event occurs in the second voltage source and the first voltage source is grounded, the first NPN element is turned on to reduce the first PNP element and the first PNP element. 2. The on-resistance of the PNP element. Such as the electrostatic discharge protection circuit of claim 10, wherein there is a first equivalent impedance between the first emitter and the first base, and there is a second equivalent between the second emitter and the second base. Effective impedance, there is a third equivalent impedance between the third base and the first voltage source. For example, the electrostatic discharge protection circuit of claim 13, further comprising: a third PNP element having a fourth collector, a fourth emitter, and a fourth base, and the fourth collector is coupled to the second emitter , The fourth emitter is coupled to the second voltage source; a second NPN device has a fifth collector, a fifth emitter and a fifth base, the fifth collector is coupled to the fourth base Pole, the fifth emitter is coupled to the second base, the fifth base is coupled to the first voltage source; and a third NPN element having a sixth collector, a sixth emitter, and a first Six bases, the sixth collector is coupled to the second voltage source, the sixth emitter is coupled to the first base, and the sixth base is coupled to the first voltage source. Such as the electrostatic discharge protection circuit of claim 14, 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 conduction. For example, the electrostatic discharge protection circuit of claim 14, wherein there is a fourth equivalent impedance between the fourth base and the second voltage source, and there is a fifth equivalent impedance between the fifth base and the second voltage source Effective impedance, there is a sixth equivalent impedance between the sixth base and the second voltage source.

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