CN104167435B - On-chip high-voltage resistor with voltage dividing ring structure - Google Patents

Abstract

The invention discloses an on-chip high-voltage resistor with a voltage dividing ring structure, which includes a P substrate, a low-doped N-type deep well region, a PW ring and a P+ ring; the P substrate, the low-doped N-type deep well Field oxygen is also grown on the upper surface of the region and the PW ring; the first Poly and the second Poly are arranged in the upper middle of the surface field oxygen on the low-doped N-type deep well region, and the first Poly and the second Poly do not fit together. A first NW ring and a second NW ring are also diffused on the P substrate, and the first and second NW rings are arranged below the field oxygen, and the specific positions are the periphery of the low-doped N-type deep well region, Within the PW ring, and the first NW ring is not bonded to the low-doped N-type deep well region, the second NW ring is not bonded to the PW ring, and the first NW ring is not bonded to the second NW ring; the second Poly is connected to the first Poly through the internal connection terminal of the resistor. The invention can specifically meet the requirements of AC-DC circuits working in a high-voltage environment.

Description

An On-Chip High Voltage Resistor with Divider Ring Structure

technical field

The invention discloses an on-chip high-voltage resistor with a voltage dividing ring structure, and relates to the technical field of semiconductor device manufacturing.

Background technique

With the development of high-voltage integrated circuits, especially for some AC-DC circuits used for high-voltage alternating current, some resistors need to withstand hundreds of volts of high voltage. However, before reaching a high enough voltage, traditional high-voltage resistors It may encounter the problem of device breakdown, which makes the traditional active resistors unable to meet the requirements. By making a polycrystalline resistor on the field oxygen, its withstand voltage can be greatly improved. The withstand voltage mainly depends on the thickness of the field oxygen. Generally, the withstand voltage of the field oxygen can reach 300~400V. However, for AC-DC circuits with high-voltage alternating current, the highest peak voltage may be as high as 500~650V, so polycrystalline resistors with conventional structures cannot meet the requirements.

Contents of the invention

The technical problem to be solved by the present invention is to provide an on-chip high-voltage resistor with a voltage divider ring structure in view of the defects of the prior art, which can specifically meet the requirements of AC-DC circuits working in a high-voltage environment.

The present invention adopts the following technical solutions for solving the problems of the technologies described above:

An on-chip high-voltage resistor with a voltage divider ring structure, including a P substrate, a low-doped N-type deep well region diffused in the center of the P substrate, and a low-doped N-type deep well region diffused around the P substrate The PW ring and the P+ ring diffused on the PW ring and inside the PW ring; field oxygen is also grown on the upper surface of the P substrate, the low-doped N-type deep well region, and the PW ring; the low-doped N The upper middle of the surface field oxygen in the type deep well region is provided with a first poly, and a second poly is provided around the first poly, the first poly and the second poly are not bonded, and on the P substrate A first NW ring is diffused, and a second NW ring is also diffused around the first NW ring. The first and second NW rings are arranged below the field oxygen, and the specific position is the periphery of the low-doped N-type deep well region. , within the PW ring, and the first NW ring is not bonded to the low-doped N-type deep well region, the second NW ring is not bonded to the PW ring, and the first NW ring is not bonded to the second NW ring;

The second Poly is used as a resistor body of a high-voltage resistor, the second Poly is connected to the first Poly through the internal connection end of the resistor, and the second Poly is connected to the low-voltage module of the integrated circuit through the external connection end of the resistor.

As a further preferred solution of the present invention, the P substrate is low-doped, and the material is a P-type silicon material sheet.

As a further preferred solution of the present invention, the concentrations of the P substrate and the low-doped N-type deep well region are adjusted according to practical applications.

As a further preferred solution of the present invention, the first Poly is cylindrical, and the second Poly is a spiral ring and is arranged around the first Poly.

As a further preferred solution of the present invention, the diameter of the first Poly is 60-100um.

As a further preferred solution of the present invention, the shapes of the P substrate and the low-doped N-type deep well region are cylinders, and correspondingly, the PW ring, P+ ring, first NW ring, and second NW ring are circular in shape.

As a further preferred solution of the present invention, the shape of the low-doped N-type deep well region and the first Poly is square or polygonal, and correspondingly, the second Poly, the first NW ring, the second NW ring, the PW ring and the P+ The shape of the ring is also set as a square ring or a polygonal ring.

As a further preferred solution of the present invention, the first Poly is used as the lead-out terminal of the packaging pressure point or connected to the internal connection point of the integrated circuit, and its size is adjusted according to actual application conditions.

As a further preferred solution of the present invention, the second Poly realizes the adjustment of the resistance value of its high voltage resistor through the adjustment of the length and width.

As a further preferred solution of the present invention, the distance between the first NW ring and the low-doped N-type deep well region, the distance between the second NW ring and the first NW ring, and the distance between the PW ring and the second NW ring are all based on actual process requirements Make adjustments.

Compared with the prior art, the present invention adopts the above technical scheme, and has the following technical effects: the present invention uses field oxygen and a low-doped N-type deep well region with a voltage divider ring structure to jointly withstand hundreds of volts of high voltage, and The voltage divider ring structure can make the low-doped N-type deep well region withstand a higher voltage than the conventional NW, and can be adjusted by adjusting the concentration of the low-doped N-type deep well region and the area of the first Poly according to the actual situation. Parasitic capacitance, so as to reasonably distribute the voltage borne by the field oxygen and the low-doped N-type deep well region, so that the withstand voltage of the entire structure reaches the highest.

Description of drawings

Fig. 1 is the longitudinal structural diagram of the on-chip high-voltage resistor with voltage divider ring structure of the present invention;

Fig. 2 is the plane structural diagram of the on-chip high-voltage resistor with voltage divider ring structure of the present invention;

Fig. 3 is the vertical structure application diagram of the high voltage resistor on the chip with the voltage divider ring structure of the present invention;

Fig. 4 is the planar connection explanatory diagram of the on-chip high voltage resistor with voltage divider ring structure of the present invention;

Fig. 5 is the internal parasitic explanatory diagram of the on-chip high voltage resistor with voltage divider ring structure of the present invention;

Fig. 6 is the application equivalent circuit diagram of the on-chip high voltage resistor with voltage divider ring structure of the present invention;

Among them: 100 is the P substrate, 101 is the low-doped N-type deep well region, 102 is the first NW ring, 103 is the second NW ring, 104 is the PW ring, 105 is the P+ ring, 106 is the field oxygen, 107 is The first Poly, 108 is the second Poly.

detailed description

Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:

As shown in Figure 1, it is the longitudinal structural diagram of the high-voltage resistor on the chip with the band voltage divider ring structure of the present invention, the P substrate is a low-doped P-type silicon material sheet, and the low-doped N-type deep well region and the P substrate form The withstand voltage of the PN junction depends on their doping concentration, so the low-concentration low-doped N-type deep well region and the P substrate are conducive to improving the withstand voltage of the PN junction.

The breakdown of the PN junction generally occurs on the silicon surface, mainly due to the curvature of the silicon surface and the poor state of the interface between the silicon and the oxide layer, which leads to the concentration of the surface electric field, and the strength of the surface electric field is higher than that of the body. The introduction of the first NW ring and the second NW ring can reduce the strong electric field caused by the curvature effect on the surface of the PN junction, thereby greatly improving the breakdown voltage of the low-doped N-type deep well region and the P substrate.

The PW ring and the P+ ring inside the PW ring are the leads of the P substrate, and are generally connected to zero potential in integrated circuit applications.

Field oxygen (FOX) grows on the surface of the silicon wafer except for the lead out of the P+ ring, which plays the role of electrical isolation. The breakdown voltage of FOX depends on its thickness. In the conventional process, the withstand voltage of FOX is 300~400V.

Both the first Poly and the second Poly are grown on the FOX, and both are inside the low-doped N-type deep well region. The second Poly is the resistor body of the high voltage resistor.

As shown in Figure 2, it is a planar structure diagram of an on-chip high-voltage resistor with a voltage divider ring structure. The first Poly is in the middle, the second Poly is spiral, and surrounds the first Poly. Both the first Poly and the second Poly are at the bottom. Inside the doped N-type deep well region, the first NW ring surrounds the low-doped N-type deep well region, the second NW ring surrounds the first NW ring, the PW ring surrounds the second NW ring, and the P+ ring is in the middle of the PW ring , as the ohmic contact terminal of the PW ring.

Figure 3 is an application diagram of the longitudinal structure of an on-chip high-voltage resistor with a voltage divider ring structure, the second internal connection terminal 108A is connected to the first Poly, and connected to the external high-voltage power supply Vin, and the external connection terminal 108B of the second Poly is connected to the integrated circuit The internal module, the connection point is VB, the voltage of Vin can reach up to about 650V, the voltage of VB is zero to tens of volts, and the P substrate is connected to Gnd through the PW ring and the P+ ring.

Figure 4 is to illustrate the connection relationship between the first Poly and the second Poly and the two connection ends 108A and 108B of the second Poly. The external terminus is connection terminal 108B, which is connected to integrated circuit module VB.

Figure 5 is an illustration of the internal parasitics of the on-chip high-voltage resistor with a voltage divider ring structure. The low-doped N-type deep well region and the P substrate form a parasitic capacitance C _DNW and a parasitic diode D _DNW . The capacity of the parasitic capacitance C _DNW is related to the low doping The concentration of the doped N-type deep well region and the P substrate is directly proportional, that is, the lighter the concentration of the low-doped N-type deep well region and the P substrate, the smaller the capacity of the parasitic capacitance C _DNW ; and the withstand voltage of the parasitic capacitance C _DNW It is equal to the withstand voltage of the parasitic diode D _DNW , which is the avalanche breakdown voltage of the low-doped N-type deep well region and the P substrate, and its breakdown voltage is proportional to the concentration of the low-doped N-type deep well region and the P substrate. Inversely proportional, that is, the lighter the concentration of the low-doped N-type deep well region and the P substrate, the higher the breakdown voltage. Due to the introduction of the first NW ring and the second NW ring of the voltage divider ring, its withstand voltage can reach up to about 400~500V.

The parasitic capacitance C _OX is formed by the first Poly, field oxygen and low-doped N-type deep well region, and its capacity mainly depends on the area of the first Poly and the thickness of the field oxygen. The thickness of the field oxygen is fixed in the process, and the size of the parasitic capacitance C _OX can be adjusted by adjusting the area of the first Poly.

Figure 6 is an equivalent circuit diagram for the application of high-voltage resistors on-chip with a voltage divider ring structure. C _DNW and C _OX are connected in series between Vin and Gnd, so the hundreds of volts of Vin are shared by C _DNW and C _OX , the value of its withstand voltage is inversely proportional to the capacity of the capacitor, that is, the larger the capacitor in C _DNW and C _OX , the smaller the withstand voltage. For C _OX , its withstand voltage is determined by the thickness of FOX. Once its voltage approaches or exceeds its withstand voltage, the oxide layer will burn and cause the entire device to fail; while the withstand voltage of C _DNW is determined by the avalanche breakdown of the PN junction, it Have a certain withstand voltage and current capability. Therefore, the values of C _DNW and C _OX can be adjusted so that C _DNW <C _OX , so that C _DNW can withstand a higher voltage. Reducing the concentration of the low-doped N-type deep well region can make C _DNW smaller, and increasing the area of the first Poly can make C _OX larger.

The high-voltage resistor HVR formed by the second Poly can withstand a high enough voltage as long as the resistance value is large enough and the width is wide enough. Through the field oxygen and the low-doped N-type deep well region structure with a voltage divider ring, the high-voltage resistor, that is, the first Poly, can withstand a voltage of up to 700~800V.

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and can also be made without departing from the gist of the present invention within the scope of knowledge possessed by those of ordinary skill in the art. Variations.

Claims (10)

1. a high-tension resistive on the sheet of band potential dividing ring structure, the low-doped n type deep-well region including substrate P, being diffused in center in substrate P, the p-well ring being diffused in substrate P around low-doped n type deep-well region and be diffused on p-well ring and be in the P+ ring within p-well ring；Also grow have an oxygen at described substrate P, low-doped n type deep-well region, the upper surface of p-well ring；Upper center at upper surface field, low-doped n type deep-well region oxygen is provided with the first polycrystalline, it is provided around the second polycrystalline at described first polycrystalline, first polycrystalline and the second polycrystalline are not fitted, it is characterized in that: in described substrate P, be also diffused with a N trap ring, the surrounding of the oneth N trap ring is also diffused with the 2nd N trap ring, described first, 2nd N trap ring is arranged at the lower section of an oxygen, particular location is the periphery of low-doped n type deep-well region, within p-well ring, and, do not fit in oneth N trap ring and low-doped n type deep-well region, 2nd N trap ring and p-well ring are not fitted, oneth N trap ring and the 2nd N trap ring are not fitted；

Described second polycrystalline is connected by resistance internal connection end and the first polycrystalline as the resistive element for high-tension resistive, the second polycrystalline, and the second polycrystalline is connected with the low-voltage module of integrated circuit by resistance external connection terminal.

High-tension resistive on the sheet of a kind of band potential dividing ring structure the most as claimed in claim 1, it is characterised in that: described substrate P is low-doped, and material is P-type silicon material piece.

High-tension resistive on the sheet of a kind of band potential dividing ring structure the most as claimed in claim 2, it is characterised in that: the concentration of described substrate P and low-doped n type deep-well region is adjusted according to reality application.

High-tension resistive on the sheet of a kind of band potential dividing ring structure the most as claimed in claim 1, it is characterised in that: described first polycrystalline is cylindrical, and described second polycrystalline is spiral ring, arranges round the first polycrystalline.

High-tension resistive on the sheet of a kind of band potential dividing ring structure the most as claimed in claim 4, it is characterised in that: the diameter of described first polycrystalline takes 60 ~ 100um.

High-tension resistive on the sheet of a kind of band potential dividing ring structure the most as claimed in claim 1, it is characterized in that: described substrate P and low-doped n type deep-well region be shaped as cylinder, corresponding, described p-well ring, P+ ring, a N trap ring, the shape of the 2nd N trap ring are circular.

High-tension resistive on the sheet of a kind of band potential dividing ring structure the most as claimed in claim 1, it is characterized in that: described low-doped n type deep-well region and the first polycrystalline be shaped as square or polygon, accordingly, the shape of the second polycrystalline, a N trap ring, the 2nd N trap ring, p-well ring and P+ ring is also configured as Q-RING or polygon ring.

High-tension resistive on the sheet of a kind of band potential dividing ring structure the most as claimed in claim 1, it is characterised in that: described first polycrystalline is as encapsulation pressure point exit or is connected to IC interior junction point, and its size is adjusted according to practical situations.

High-tension resistive on the sheet of a kind of band potential dividing ring structure the most as claimed in claim 1, it is characterised in that: described second polycrystalline regulation by length and width, it is achieved the adjustment of its high-tension resistive resistance size.

High-tension resistive on the sheet of a kind of band potential dividing ring structure the most as claimed in claim 1, it is characterised in that: a N trap ring requires to be adjusted all in accordance with actual process with the spacing of spacing, the 2nd N trap ring and the spacing of a N trap ring, p-well ring and the 2nd N trap ring of low-doped n type deep-well region.