CN100440505C

CN100440505C - Depletion type terminal protection structure

Info

Publication number: CN100440505C
Application number: CNB200610096438XA
Authority: CN
Inventors: 易扬波; 李海松
Original assignee: WUXI POWERON MICROELECTRONICS CO Ltd
Current assignee: Suzhou Poweron IC Design Co Ltd
Priority date: 2006-09-26
Filing date: 2006-09-26
Publication date: 2008-12-03
Anticipated expiration: 2026-09-26
Also published as: CN1929126A

Abstract

This invention relates to wear out terminal protection structure to protect power integration circuit or power parts, which comprises the following parts: mixture N shape underlay with N shape extension and N shape terminal ring to set power integration circuit or power original chamber; the N shape extension terminal ring and chamber area top are set with field oxidation layer with multiple crystal field boards and medium layer on board.

Description

Depletion type terminal protection structure

Technical field

The present invention relates to a kind of protection structure, relate in particular to a kind of depletion type terminal protection structure that is used to protect power integrated circuit or power device.

Background technology

Terminal structure is one of technology most crucial in power device and the power integrated circuit, and the quality of terminal structure directly has influence on power device and power integrated circuit maximum operating voltage, leakage current, and reliability and stability.

Fig. 5 has provided traditional power device and power integrated circuit terminal structure.This structure mainly comprises following components: (1) heavy doping P type trap, and (2) polycrystalline field plate structure, (3) N+ type is by ring.In actual applications, by around chip, having made several heavy doping P type trap, and regulate the width of P type trap and the field plate structure on spacing and the auxiliary P type trap, realize withstand voltage and improve the purpose of reliability.

Traditional structure is widely used in power device, however some application scenario, and traditional structure can be subjected to the restriction of cost, because the general area of traditional structure is bigger.

Depletion type terminal structure of the present invention, use the heavy doping P type trap of doped with P type trap replace traditional structural, can effectively reduce the terminal structure area more than 30%, and also have on the performance and improve, therefore depletion type terminal structure of the present invention is a kind of better selection of power device and power integrated circuit.

Summary of the invention

The invention provides a kind of depletion type terminal protection structure that can reduce cost of manufacture and manufacture difficulty and can improve the protection effect, the present invention helps to improve withstand voltage effect and reliability.

The present invention adopts following technical scheme:

A kind of depletion type terminal protection structure that is used to protect power integrated circuit or power device; comprise: heavy doping N type substrate; on heavy doping N type substrate, be provided with light dope N type extension; on light dope N type extension, be provided with heavy doping N type by the cavity that encircles and be used to be provided with power integrated circuit or power device primitive unit cell; heavy doping N type in light dope N type extension is provided with field oxide above the zone beyond ring and the primitive unit cell cavity; above field oxide, be provided with the polycrystalline field plate; at field oxide; heavy doping N type is covered with dielectric layer on ring and polycrystalline field plate; on ring and polycrystalline field plate, be connected with metal lead wire in heavy doping N type respectively; be provided with the doped with P type trap of connecting to neutral current potential on light dope N type extension, this doped with P type trap ends between ring and the primitive unit cell cavity below field oxide and in heavy doping N type.

Compared with prior art, the present invention has following advantage:

(1) novel depletion type terminal structure is than the weak point of conventional terminal structure more than 30%.Because terminal structure is positioned at the outermost of chip, self area is generally bigger, and therefore novel depletion type terminal structure can effectively be saved chip area, reduces cost.

(2) the depletion type terminal structure is bigger to the redundancy of process deviation; because doped with P type trap connecting to neutral current potential; link to each other with the zero potential of protected part; when on substrate, adding high potential; doped with P type trap can exhaust gradually; thereby reach withstand voltage effect, in this structure, the error of trap is very little to the protection influential effect.And in the conventional terminal structure, the size or the position of withstand voltage effect and polycrystalline field plate, and very responsive between the spacing of heavy doping P type trap itself, and process deviation is bigger to the terminal structure influential effect.

(3) the depletion type terminal structure can effectively increase power integrated circuit or power device parasitic diode area, because the parasitic diode size is closely related with chip reliability, so novel depletion type terminal structure helps the protection to chip.

(4) in the depletion type terminal structure, zero potential polycrystalline field plate can make doped with P type trap potential line distribution when exhausting more even, can assist doped with P type trap to improve withstand voltage effect and reliability.According to concrete application scenario, the length that field plate extends to doped with P type trap needs to adjust.Because field plate is a zero potential, is not the field plate of floating in the traditional structure, anti-interference aspect can be relatively good.

(5) heavy doping N type can play by ring and collect the chip edge potential lines in the depletion type terminal structure, improves withstand voltage.

Description of drawings

Fig. 1 is the depletion type terminal structural front view.

Fig. 2 is a depletion type terminal structure vertical view.

Fig. 3 is that the depletion type terminal structure is used to protect vertical conduction power device primitive unit cell schematic diagram.

Fig. 4 is that the depletion type terminal structure is used to protect control circuit P type trap schematic diagram.

Fig. 5 is the conventional terminal structure.

Embodiment

A kind of depletion type terminal protection structure that is used to protect power integrated circuit or power device; comprise: heavy doping N type substrate 1; on heavy doping N type substrate 1, be provided with light dope N type extension 2; on light dope N type extension 2, be provided with the cavity 5 that heavy doping N type ends ring 3 and is used to be provided with power integrated circuit or power device primitive unit cell; heavy doping N type in light dope N type extension 2 is provided with field oxide 6 above the zone beyond ring 3 and the primitive unit cell cavity 5; above field oxide 6, be provided with polycrystalline field plate 7; at field oxide 6; heavy doping N type is covered with dielectric layer 8 on ring 3 and polycrystalline field plate 7; on ring 3 and polycrystalline field plate 7, be connected with metal lead wire 9 in heavy doping N type respectively; 10; be provided with the doped with P type trap 4 of connecting to neutral current potential on light dope N type extension 2, this doped with P type trap 4 ends between ring 3 and the primitive unit cell cavity 5 below field oxide 6 and in heavy doping N type.1 polycrystalline field plate 7 is set above field oxide 6.The execution mode of the doped with P type trap 4 of above-mentioned connecting to neutral current potential can be that doped with P type trap 4 is connected with the primitive unit cell cavity, makes them idiostatic.When the present invention was provided with the power device primitive unit cell in primitive unit cell cavity 5, the present invention was a kind of depletion type terminal protection structure (with reference to Fig. 3) that is used to protect power device; When the present invention was provided with power integrated circuit in primitive unit cell cavity 5, the present invention was a kind of depletion type terminal protection structure (with reference to Fig. 4) that is used to protect power integrated circuit.

Claims

1; a kind of depletion type terminal protection structure that is used to protect power integrated circuit or power device; comprise: heavy doping N type substrate (1); on heavy doping N type substrate (1), be provided with light dope N type extension (2); on light dope N type extension (2), be provided with the cavity (5) that heavy doping N type ends ring (3) and is used to be provided with power integrated circuit or power device primitive unit cell; be provided with field oxide (6) in the heavy doping N of light dope N type extension (2) type by ring (3) and primitive unit cell cavity (5) top, zone in addition; be provided with polycrystalline field plate (7) in field oxide (6) top; in field oxide (6); heavy doping N type is covered with dielectric layer (8) on ring (3) and polycrystalline field plate (7); on ring (3) and polycrystalline field plate (7), be connected with metal lead wire (9 in heavy doping N type respectively; 10); it is characterized in that being provided with on light dope N type extension (2) the doped with P type trap (4) of connecting to neutral current potential, this doped with P type trap (4) is positioned at the following of field oxide (6) and is positioned at heavy doping N type between ring (3) and primitive unit cell cavity (5).

2, depletion type terminal protection structure according to claim 1 is characterized in that in field oxide (6) top 1 polycrystalline field plate (7) being set.