TW492177B - Electrostatic discharge protection device for silicon controlled rectifier with adjustable trigger potential - Google Patents

Abstract

The electrostatic discharge protection device with silicon controlled rectifier according to the present invention comprises a P-well, a N-well formed in the P-well, a first p-type doping region formed in the N-well, a n-type doping region formed in the P-well, and a second p-type doping region formed in the P-well. The present invention is characterized in using the distance from the edge of the first p-type doping region in the N-well to the intersection of the N-well to adjust the trigger voltage of the SCR, and saving the area for producing the transistors.

Description

492177 V. Description of the invention α) Field of the invention The present invention relates to an electrostatic discharge protection element, particularly an adjustable potential silicon controlled rectifier (SCR) electrostatic discharge protection element (ESD) ° Background of the invention Micron process technology has been widely used to improve the performance and operating speed of integrated circuits to reduce the cost of each chip. However, the protection ability of sub-micron integrated circuits & products in electrostatic discharge is reduced due to the reduction in component size. Therefore, the damage of sub-micron M0S integrated circuits due to ESD is more serious. For the technology and industry of integrated circuits Electrostatic discharge (ESD) damage is an important factor affecting the yield and reliability of integrated circuit products. For an integrated circuit formed of a metal-oxide-semiconductor field-effect transistor, the externally input signal is connected to the gate of the metal-oxide-semiconductor field-effect transistor. If the voltage of the external input signal is too large, the gate dielectric layer will break down and damage the device. The gate dielectric layer is usually an oxide layer, and its anti-voltage strength is about i E 7 to 2 E 7 volts / cm. In terms of the sub-micron process, the thickness of the gate dielectric layer is only about 40A, and it can only withstand voltages of 4 to 8 volts. If the external input signal is greater than 8 volts, the dielectric dielectric layer will collapse. Although the current working voltage of the integrated circuit is generally 丄 / / V. Description of the invention (2) is generally 3.3 or 2.5 volts, which is lower than the 8 volts described in ###. Whether the logic element can be higher than 2_ volts, or even 2 f :: static electricity with extremely high voltage (the internal components of the circuit can be damaged. Because = :: special): resulting in integrated electricity

Ten pairs of integrated circuit female one-pin bonding pads (bonding pads) must be equipped with static discharge prevention circuits between the connection pads such as-, L φ ^ ^ ^ ^ In order to ground the external high-voltage electrostatic discharge before it enters the internal components. The current topic is how to protect integrated circuit components from being affected by high-voltage electrostatic discharge. At present, the industry standard must be able to withstand large ESD voltages to ensure product reliability. A method for forming E S D can be found in U.S. patent u s ρ ν 0.

United States Patent 6, 011, 420, the inventor is Watt, etc., the invention name is "ESD protection apparatus having floating r ESD bus and semi conductor structure", which discloses one kind of _ electrostatic discharge protection circuit. Another is related to the method of forming ESD See USP No. United States Patent 5, 872, 379, the invention name is " Low voltage turn-on SCR for ESD protect ionn, the inventor is one of the inventors of this case, and the patent is transferred to the applicant of this case. One of the other structures to achieve electrostatic discharge protection is the structure using a Silicon Controlled Rectifier (SCR) to conduct the charge away. Generally, it includes P-type / N-type / P-type / N-type structures A type is called low critical voltage silicon controlled rectifier (L 〇w-V ο 11 age Triggered Silicon Controlled Rectifier; LTVSCR),

Page 5 492177 V. Description of the invention (3) It has been developed to use low resistance in the on state to protect sensitive components. 1 ^ LVTSCR includes a transistor structure, the drain and source regions of which are formed between the P-type substrate across the N-well. In addition, USP No. United States Patent 5,465,189. The previous technology mentioned above uses NMOS as the trigger source (tr i gger source), but the trigger potential depends on the breakdown voltage of NMOS. The SC_generating bit of the prior art is too high for ESD protection, so NMOS must be added to reduce the SC trigger circuit. And the above NMOS will take up area. Object and Summary of the Invention: In view of the different disadvantages of the prior art, the object of the present invention is to provide an electrostatic discharge protection element with adjustable trigger potential. The silicon controlled rectifier (SiliC (Dn hntNiied m / m)) electrostatic discharge protection element of the present invention includes: a p-type substrate or a p-type impurity & domain, formed into a p-type substrate or a p-type well; The first p-type doped region is formed in the above-mentioned N-type well _ P-type substrate or P-type well; the second _-doped region is formed in the above-mentioned substrate or P-type well; and the region may be formed From the edge of the search area to the -P type doping voltage of the d; well, and save the surface area of the transistor. The distance is adjusted and triggered. 492177 Five invention descriptions (4) Detailed description of the invention: The present invention discloses an electrostatic discharge protection element of a Silicone Control Rectifier (Siliconctrotrolcl if ifT; SCR). The present invention generates a "account state =: can have a better electrostatic discharge protection effect, and the present invention does not require": = Add NMOStc parts to trigger the potential, and can reduce the generation of power generation, the present invention can use a physical distance to adjust the trigger potential 0 The static thunder release thunder exposed by the present invention #-^ / Sheshe Qianxi Warranty濩 件 （ESD Protect ion）, ... The one in Fig. Configured comprising a silicon-controlled

Controlled Rectifier (Slllcon is formed in a p-type substrate or p-type well, and σ, the two main structures include the gambling well domain. In addition, a P-type substrate or a p-type well in / inclusive of ":, including the doped region. ^ 3 N-type and P-type doped regions are formed in the P-type doped region formed in the p-type substrate or in the substrate of the p-type well. The inner doped region is formed with the P-type $ metal pad 4. The N-type well is used. P-type doped region coupling for p-type doped ^ -type wells

The distance d formed by the boundary can be adjusted from the edge to the N-type well? Type $ is the area of the transistor. That is to say, the voltage at the SCR is triggered to save the distance of the miscellaneous area, so the value of the dioxin can be small with the N-type well to which the p-type is mixed. Area of LVTSCR of the prior art

492177 V. Description of the invention (5) Figures 1 and 3 are top views of the layout of the present invention. It contains a P + guard ring 6, which is coupled to the potential VSS. An N-type well 8 is formed in the guard ring 6, which can generally be a rectangular space (shown in Figure 3) or a rectangular space with extensions at both ends (Figure (1)) The above-mentioned extension includes an N + contact pad (pad) 10 disposed thereon. P + contact pads (pa (j) 1 2 are arranged on the main body of the rectangular space. N + planting areas 1 4 are arranged on both sides of the above-mentioned n-type wells. The aforementioned P + guard rings 6 and N + planting areas 14 The surface is uniformly connected to VSS (or ground). The distance from the periphery of the p + contact pad 2 to the edge of the N-type well is used to determine the value of the trigger circuit. Therefore, the present invention can use specific physical parameters to determine static electricity. The electrical property of the discharge protection circuit. Figure 4 shows the electrical comparison between the prior art and the present invention. The square curve represents the electrical property of the previous electrostatic discharge protection circuit with NMOS. In the state of volts, its current is about 960 m A; and in the human body model test, the current is about 2.5 kV, and its current is about 2.55 A. The electrical iron of the invention is superior to the prior art .... In summary, the present invention utilizes the distance d formed by the edge of the P-type doped region of the N-type well to the boundary between the gambling well and the P-type well can be adjusted. The SCR generates a voltage, which can not only be used to adjust the trigger potential, but also save the area of the electric body. The electrical properties are also better than the prior art. Βθ Although the present invention is explained above with a preferred embodiment, it is not ^ I pv.

Page 8 492177 V. Description of the invention (6) It is determined that the spirit and the invention entity of the present invention are limited to this embodiment. For example, the forms of doped regions can be transposed, and those skilled in the art will not depart from the present invention. Within the scope of the spirit, it can be modified slightly, and the scope of its patent protection depends on the scope of the attached patent application and its equivalent. For example, the above-mentioned conductive type impurities, N-type and P-type are interchangeable with each other, and the present invention is also applicable.

Page 9 492177 Brief description of the drawings Figure 1 shows a sectional view of the electrostatic discharge protection element of the present invention. FIG. 2 is a plan layout view of the electrostatic discharge protection element of the present invention. FIG. 3 is a plan layout view of the electrostatic discharge protection element of the present invention. FIG. 4 shows a comparison of electrical properties between the prior art and the present invention. Symbol comparison: base plate 2 metal cymbals 4 guard ring 6 N-type well 8 N + contact pad (pad) 10 P + contact pad (pad) 12 N + planting area 14

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Claims (1)

Sixth, the scope of patent application 1. A silicon controlled w SCR) electrostatic discharge snow ridge, L type (Silicon Controlled Rectifier; p type and its 4 protection elements include: a base plate or P type 丼. N type well ,, soil 汴, The first ㈣Z is formed in the p-type substrate or p-type well; the N-type doped W region / formed in the N-type well; the second P-type doped domain / formed in the p-type substrate or p-type well; And 'hetero-regions' formed on the above-mentioned P-type substrate or p-type well can be used as the first type-doped region edge of the N-type well at the junction of the type-well junction to the above-mentioned N for electricity. The distance of the area is used to adjust the trigger voltage of the SCR and save the system. 2) Such as the patented patent document, where the first P-type doped region on the silicon controlled rectifier electrostatic discharge protection element is connected to— Metal pads, such as:: nf 1 The silicon-controlled rectifier electrostatic discharge protection element of the second P-type doped region in the upper surface of the silicon element is grounded to the ground. Protection element 4 · If the first item of the scope of the patent application, Straight in the middle, +, and the heart 丨 while controlling positive, Gua Yi static discharge, the above 'doping The area is coupled to the ground. 5. A silicon-controlled rectifier electrostatic discharge protection element p + guard ring; 3. N-type well formed inside the guard ring; 492177 VI. Patent application scope P + contact pads are arranged on the main body of the N-type well; N + planting area is arranged on both sides of the N-type well; and the distance from the periphery of the P + contact pad to the edge of the N-type well, use To determine the trigger circuit value. 6. For example, the silicon-controlled rectifier electrostatic discharge protection element of the scope of patent application No. 5, wherein the N-type well further includes an extension part, and the extension part includes N + contact pads arranged on it. 7. For the silicon-controlled rectifier electrostatic discharge protection element of the scope of the patent application, the above-mentioned P + guard ring is grounded. 8. If the silicon-controlled rectifier electrostatic discharge protection element of item 5 of the patent application scope, wherein the above N + planting area is grounded. 9. A Silicon Controlled Rectifier (SCR) electrostatic discharge protection element includes: an N-type substrate or an N-type well; a P-type well formed in the N-type substrate or an N-type well; a first N-type doped The impurity region is formed in the P-type well; the P-type doped region is formed in the N-type substrate or the N-type well; the second N-type doped region is formed in the N-type substrate or the N-type well; And can use the edge of the first N-type doped region of the P-type well to the P Page 12 492177 VI. Scope of patent application The distance formed by the junction of the wells can be used to modulate the SCR trigger voltage and save the area of making / making transistors. 10. The silicon-controlled rectifier electrostatic discharge protection element according to item 9 of the patent application scope, wherein the above-mentioned first N-type doped region is connected to a metal pad. 11. The silicon-controlled rectifier electrostatic discharge protection element according to item 9 of the patent application scope, wherein the second N-type doped region is coupled to ground. 1 2. The silicon-controlled rectifier electrostatic discharge protection element according to item 9 of the scope of the patent application, wherein the aforementioned P-type doped region is coupled to the ground. 1 3. — A kind of silicon-controlled rectifier electrostatic discharge protection element includes: N + guard ring; — P-shaped well formed in the above-mentioned guard ring; N + contact pads are produced and arranged on the main body of the P-shaped well; P + planting The area is arranged on both sides of the F-type well; and the distance from the periphery of the N + contact pad to the edge of the P-type well is used to determine the trigger circuit value. 1 4. The silicon-controlled rectifier electrostatic discharge protection element according to item 13 of the scope of the patent application, wherein the P-shaped well further includes an extension part, and the extension part includes P + contact pads arranged on it. Page 13 492177 VI. Scope of patent application 1 5. For the silicon-controlled rectifier electrostatic discharge protection element of item 13 of the patent application scope, the above-mentioned N + guard ring is grounded. 16. The silicon-controlled rectifier electrostatic discharge protection element according to item 13 of the scope of patent application, wherein the above-mentioned P + planting area is grounded.