A kind of new E SD protection device based on SCR structure
Technical field
The invention belongs to integrated circuit electrostatic discharge (ESD-Electrostatic Discharge) and protect field, relate to a kind of new E SD protection device based on SCR structure.
Background technology
Static discharge (ESD) phenomenon is extensively present in occurring in nature, and it is also one of major reason causing integrated circuit (IC) products to lose efficacy.Integrated circuit (IC) products is manufactured at it and is easy to the impact being subject to static discharge in assembling process, causes the reliability of product to reduce, even damages.Therefore, the electrostatic discharge protection component that research reliability is high and electrostatic defending performance is strong and protection circuit have very important effect to the rate of finished products and reliability that improve integrated circuit.
According to static discharge Producing reason and the difference to integrated circuit discharge mode thereof, static discharge is divided into following four kinds of pattern: HBM (human-body model) usually, MM (machine discharge mode), CDM (assembly charging and discharging pattern), FIM (electric field induction pattern).Wherein, HBM and MM pattern is modal is also two kinds of static discharge patterns that industrial quarters is concerned about the most.When integrated circuit generation static discharge phenomenon, a large amount of electric charge flows into the pin of chip instantaneously, and the electric current that these circuit produce usually can large several amperes of sizes, and the voltage produced at this pin place is up to a few volt even tens volts.Larger electric current and higher voltage can cause puncturing of the infringement of chip internal circuits and device, thus cause the inefficacy of circuit function.Therefore, in order to the damage preventing chip to be subjected to ESD, just need will carry out effective ESD protection to each pin of chip.Usually, the design of ESD protective device needs the problem of consideration two aspects: one is that ESD protective device wants to release big current; Two be ESD protective device want can when chip is subject to ESD impact by the low voltage level of chip pin terminal voltage clamper in safety.
The device being typically used as esd protection has diode, GGNMOS (NMOS of grid ground connection), SCR (controllable silicon) etc.But in some special circuit and special applications, need the puncture voltage of ESD protective device higher, current drain ability is comparatively strong, also needs the ME for maintenance improving ESD device, avoids latch-up simultaneously.The invention provides a kind of new technical scheme, the ESD device of high maintenance voltage can be provided, avoid the generation of latch-up.
Summary of the invention
The object of the present invention is to provide a kind of new E SD protection device based on SCR structure, solve existing ESD device and can cause the infringement of chip internal circuits and the problem of device breakdown by larger electric current and higher voltage.
The technical solution adopted in the present invention is a kind of new E SD protection device based on SCR structure, it is characterized in that, comprise P type substrate, be provided with the first N-type trap, a P type trap and the second N-type trap in P type substrate, a P type trap is between the first N-type trap and the second N-type trap;
A N+ injection region, a P+ injection region is marked with in first N-type trap;
The 3rd N+ injection region, the 2nd P+ injection region and the 4th N+ injection region is marked with in one P type trap;
The 3rd P+ injection region and the 5th N+ injection region is marked with in second N-type trap;
Between first N-type trap and a P type trap, cross-over connection has the 2nd N+ injection region;
Between one N+ injection region and P type substrate edge, between one N+ injection region and a P+ injection region, between one P+ injection region and the 2nd N+ injection region, between 2nd N+ injection region and the 3rd N+ injection region, between 3rd N+ injection region and the 2nd P+ injection region, between 2nd P+ injection region and the 4th N+ injection region, between 4th N+ injection region and the 3rd P+ injection region, between 3rd P+ injection region and the 5th N+ injection region, be separated by by oxidization isolation layer between 5th N+ injection region and P type substrate edge,
A device interface is drawn, jointly as device cathodes in 3rd N+ injection region, the 2nd P+ injection region and the 4th N+ injection region;
A port is drawn in 3rd P+ injection region, as device anode;
One N+ injection region, utilize between a P+ injection region and the 5th N+ injection region metal wire be connected.
Further, described anode there is forward esd event interim, forward conduction diode is formed by the 3rd P+ injection region and the second N-type trap, the modified model SCR formed with a N+ injection region, the first N-type trap, a P+ injection region, the 2nd N+ injection region, the 3rd N+ injection region, the 2nd P type trap and the 2nd P+ injection region guiding path formed of connecting is opened, simultaneously, the conventional scr structure formed by the 3rd P+ injection region, the second N-type trap, the 4th N+ injection region, a P type trap and the 2nd P+ injection region is opened, and forms drain passageway.
Further, device architecture is opened by the low trigger voltage of modified model SCR, simultaneously, due to the forward PN junction conducting of the 3rd P+ injection region and the second N-type trap, the conducting of conventional scr path can be impelled, thus modified model SCR path and conventional scr path form negative feedback, reach the object of increased device ME for maintenance, the trigger voltage of device is only determined by the cut-in voltage of modified model SCR path simultaneously.
The invention has the beneficial effects as follows that protection ESD device can not by larger electric current and higher voltage damages.
Accompanying drawing explanation
Fig. 1 is the conventional scr structural profile schematic diagram that example of the present invention utilizes;
Fig. 2 is the modified model SCR structure generalized section that example of the present invention utilizes;
Fig. 3 is the conventional connected mode schematic diagram utilizing two kinds of structures in example of the present invention;
Fig. 4 be comprehensive in example of the present invention after connected mode schematic diagram.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.
For the technological deficiency that prior art exists; a kind of new E SD protection device based on SCR structure of example design of the present invention; both the feature of the strong discharge capacity of SCR structure had been made full use of; make use of again the advantage of modified model SCR low trigger voltage; be interconnected mode by amendment conventional scr and modified model SCR, maintain the feature of modified model SCR structure low trigger voltage, the negative feedback of generation between the two made again; improve ME for maintenance, the generation of latch-up can be avoided.Can realize high pressure resistant, high maintenance voltage, low on-resistance, low trigger voltage, the esd protection performances such as strong robustness.Can be used for the reliability of IC bi-directional ESD protection in improved sheet.
Below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation:
A kind of new E SD protection device based on SCR structure of example design of the present invention; by the connected mode between amendment conventional scr structure and modified model SCR structure; when not increasing extra mask version; not only realize the feature keeping modified model SCR structure trigger voltage; and negative feedback between conventional scr structure and modified model SCR structure can be utilized, thus improve the ME for maintenance of the type device.
The conventional scr structural profile schematic diagram that the present invention as shown in Figure 1 utilizes, its feature comprises: mainly contain P type substrate (101), a P type trap (102), a N-type trap (103), P type trap there is a P+ injection region (104),, N-type trap there are a P+ injection region ((106), a N+ injection region (107) and some oxide isolation regions in a N+ injection region (105) and some oxide isolation regions.
The modified model SCR structure generalized section that example of the present invention as shown in Figure 2 utilizes, its feature comprises: mainly contain P type substrate (201), a P type trap (202), a N-type trap (203), P type trap there is a P+ injection region (204), a N+ injection region (205) and some oxide isolation regions, N-type trap there is a P+ injection region (207), a N+ injection region (208) and some oxide isolation regions, a N+ injection region (206) is across on P type trap and N-type trap.
The conventional connected mode schematic diagram of two kinds of structures is utilized in example of the present invention as shown in Figure 3, a device interface Cathode is drawn jointly in P+ injection region (204) on the P well region (202) of modified model SCR and N+ injection region (205), P+ injection region (207) on N well region (203), N+ injection region (208) is connected with the N+ injection region (107) on N well region (103) in conventional scr, a device interface Anode is drawn in P+ injection region (106) on the N well region (103) of conventional scr, N+ injection region (105) on P well region (102), a device interface Cathode is drawn jointly in P+ injection region (104).Arrive when Anode there being the forward ESD time, during Cathode end ground connection, the cascaded structure conducting that the forward diode be made up of P+ injection region (106) and N well region (103) and modified model SCR device are formed, conventional scr structure conducting simultaneously, owing to employing same P+ injection region, conventional scr device and modified model SCR device can form a negative feedback, reduce injection efficiency, improve the ME for maintenance of device.
Connected mode schematic diagram after comprehensive in example of the present invention as shown in Figure 4, when the high potential of Anode termination esd pulse described in device, during Cathode end ground connection, P type substrate (301), the first N-type trap (302) is provided with in P type substrate (301), one P type trap (303) and the second N-type trap (304), described 3rd P+ injection region (311), the forward diode that second N-type trap (304) is formed with by a N+ injection region (305), first N-type trap (302), one P+ injection region (306), 2nd N+ injection region (307), one P type trap (303), the leakage paths conducting that the modified model SCR that 3rd N+ injection region (308) and the 2nd P+ injection region (309) are formed is in series, simultaneously, by the 5th N+ injection region (312), second N-type trap (304), 3rd P+ injection region (311), one P type trap (303), the SCR drain passageway conducting that 4th N+ injection region (310) and the 2nd P+ injection region (309) are formed, article two, conduction path forms negative feedback mutually, reduce current injection efficiency, improve the ME for maintenance of device, avoid latch-up occurs.
Advantageous Effects of the present invention is:
(1) CMOS technology that SCR structure of the present invention and industry are commonly used realizes process compatible, has very strong esd protection ability;
(2) the present invention does not need additionally to increase mask plate, and therefore not needing increases technique cost of manufacture;
(3) the present invention is by certain connected mode, both the feature of modified model SCR structure low trigger voltage had been maintained, utilize again the negative feedback between modified model SCR structure and conventional scr structure, improve the ME for maintenance of overall device, avoid the generation of latch-up.
What finally illustrate is, above example is only in order to illustrate technical scheme of the present invention and unrestricted, although with reference to preferred embodiments to invention has been detailed description, those of ordinary skill in the art is to be understood that, can modify to technical scheme of the present invention or equivalent replacement, and not departing from aim and the scope of technical solution of the present invention, it all should be encompassed in the middle of right of the present invention.
The above is only to preferred embodiment of the present invention, not any pro forma restriction is done to the present invention, every according to technical spirit of the present invention to any simple modification made for any of the above embodiments, equivalent variations and modification, all belong in the scope of technical solution of the present invention.