Electrostatic discharge voltage resistive current modeling method of electrostatic discharge protection device

• US 8,108,185 B2
• Filed: 12/18/2008
• Issued: 01/31/2012
• Est. Priority Date: 12/26/2007
• Status: Active Grant

• Current Assignee: DB HiTek Co., Ltd.
• Original Assignee: Dongbu HiTek Co., Ltd. (DB HiTek Co., Ltd.)
• Inventors: Jang, Chang Soo
• Primary Examiner(s): PHAN, THAI Q
• Application Number:
  US12/338,475
• Publication Number:
  US 20090171635A1
• Time in Patent Office: 1,139 Days
• Field of Search: 703/2, 703/6, 703/17, 703/5, 703/13, 703/19, 257/328, 257/360, 257/170, 257/355, 361/56
• US Class Current: 703/2
• CPC Class Codes: G06F 30/367 Design verification, e.g. using simulation, simulation program with integrated circuit emphasis [SPICE], direct methods or relaxation methods

Abstract

Provided is a method for modeling an ESD breakdown current. According to one variation, a first proportional constant is based on a circumference of the ESD protection device and a second proportional constant based on an area of the ESD protection device. A dual first order equation is derived by sampling circumferences and areas of two ESD protection devices. According to another variation, an equation is defined in which a third value (an ESD breakdown current) is a sum of a first value and a second value, the first value being obtained by multiplying a circumference of an ESD protection device by a first proportional constant, the second value being obtained by multiplying an area of the ESD protection device by a second proportional constant. Then, circumferences and areas of first and second ESD protection samples are calculated. Next, first and second equations are derived by reflecting the first and second circumferences and areas to the equation.

Claims

1. A method for modeling an electrostatic discharge (ESD) breakdown current in an ESD protection device comprising a diode including an anode and a cathode, the anode comprising a first conductivity type diffusion layer, and the cathode comprising a second conductivity type diffusion layer, the method comprising:

defining a first proportional constant based on a circumference of the anode of the ESD protection device and a second proportional constant based on an area of the anode of the ESD protection device; and

deriving a dual first order equation by sampling circumferences and areas of anodes of two ESD protection devices.

2. The method according to claim 1, further comprising calculating the dual first order equation using the first and second proportional constants as variables.

3. The method according to claim 2, further comprising calculating the first and second proportional constants for the dual first order equation to generate a model equation for the ESD breakdown current using the circumference and area of the anodes of the ESD protection devices as variables.

4. The method according to claim 3, comprising predicting a first ESD breakdown current of a first ESD protection device according to:

the first ESD breakdown current=(the first proportional constant·

a first anode circumference)+(the second proportional constant·

a first anode area).

5. The method according to claim 4, comprising predicting a second ESD breakdown current of a second ESD protection device according to:

the second ESD breakdown current=(the first proportional constant·

a second anode circumference)+(the second proportional constant·

a second anode area).

6. The method according to claim 5, wherein the first proportional constant and the second proportional constant are calculated according to:

the first proportional constant=(the first ESD breakdown current·

[the second anode area/the first anode area]−

the second ESD breakdown current)/(the first anode circumference·

[the second anode area/the first anode area]−

the second anode circumference); and

the second proportional constant=(the first ESD breakdown current·

[the second anode circumference/the first anode circumference]−

the second ESD breakdown current)/(the first anode area·

[the second anode circumference/the first anode circumference]−

the second anode area).

7. The method according to claim 6, wherein the ESD breakdown current of the ESD protection device is calculated according to:

the ESD breakdown current=(the first proportional constant·

the circumference of the ESD protection device)+(the second proportional constant·

the area of the ESD protection device).

8. The method according to claim 2, comprising:

calculating numerical values of the first and second proportional constants as constants in the dual first order equation; and

deriving a normalized model equation for the ESD breakdown current by including the circumference and area of the anode of a third ESD protection device in the dual first order equation as variables.

9. The method according to claim 1, wherein the two ESD protection devices comprise anodes having different respective sizes.

10. The method according to claim 9, wherein the anodes of the two ESD protection devices have different respective lengths and/or widths.

11. The method according to claim 1, wherein the diode comprises an N-type diffusion layer operating as the anode, a P-type diffusion layer operating as the cathode, and a junction layer between the N-type diffusion layer and the P-type diffusion layer.

12. The method according to claim 1, wherein the ESD protection device has a circumference and an area defined by the circumference and the area of the anode of the ESD protection device, respectively.

13. A method for modeling an ESD breakdown current in an ESD protection device comprising a diode including an anode and a cathode, the anode comprising a first conductivity type diffusion layer, and the cathode comprising a second conductivity type diffusion layer, the method comprising:

defining an equation in which the ESD breakdown current is a sum of a first value and a second value, the first value being obtained by multiplying a circumference of the anode of the ESD protection device by a first proportional constant, the second value being obtained by multiplying an area of the anode of the ESD protection device by a second proportional constant;

calculating a first circumference and a first area of the anode of a first sample ESD protection device and calculating a second circumference and a second area of the anode of a second sample ESD protection device; and

deriving a first equation by including the first circumference and the first area in the equation and deriving a second equation by including the second circumference and the second area in the equation.

14. The method according to claim 13, further comprising calculating a dual first order equation using the first proportional constant and the second proportional constant as variables.

15. The method according to claim 14, further comprising designing a third ESD protective device with a circumference and area providing a predetermined ESD breakdown current in accordance with the dual first order equation.

16. The method according to claim 15, further comprising fabricating an integrated circuit having the third ESD protective device designed therefor.

17. The method according to claim 13, wherein the diode comprises an N-type diffusion layer operating as the anode, a P-type diffusion layer operating as the cathode, and a junction layer between the N-type diffusion layer and the P-type diffusion layer.

18. The method according to claim 17, wherein the ESD protection device has a circumference defined by the circumference of the anode and an area defined by the area of the anode.

19. The method according to claim 13, wherein the first and second sample ESD protection devices comprise anodes having different respective sizes.

20. The method according to claim 19, wherein the anodes of the first and second sample ESD protection devices have different respective lengths and/or widths.