FABLESS SOFICS SOLUTIONS FOR BCD PROCESSES

SOFICS © 2021 Proprietary 1

SOFICS – NOVEMBER 2021

SOFICS SOLUTIONS FOR BCD PROCESSES

FABLESS


Sofics examples for BCD technology

• Introduction

• Different solution types

– High clamping voltage

– Low clamping voltage

• Conclusions

Different ESD concepts


• Many different device concepts are used in the industry

I

V

It2

VhVDD

I

V

It2

Vh Vt1VDD

I

V

It2

VDD

I

VVt1VDD

It2

Vh

I

V

It2

VhVDD Vt1

I

VVt1VDD

It2

Vh

Ilatch_spec

Zener/PNP RC-MOS NMOS/NPN

Basic SCR HHI-SCR PowerQubic clamps

Solution set for High voltage / BCD applications


• ESD with low holding voltage

– For IO interfaces

– Benefits

▪ High ESD in small area

▪ Sofics SCR

– Tunable trigger, clamping, failure current

• ESD with high holding voltage

– For power clamps

– Benefits

▪ Good Latch-up immunity

▪ PowerQubic

– Tunable trigger, clamping, failure current



• Introduction




• Conclusions

Sofics solution: PowerQubic clamps


• Tunable trigger voltage Vt1

– Customized DC and transient response

• Tunable holding voltage Vhold

– To adapt to application/requirements

• Tunable performance It2, Ron

– High current

– Low on-resistance

• …and:

– Bi-directional, standard process compatible, compact silicon area…

I

V

It2

VhVDD Vt1

Ron

PowerQubic – TSMC 0.25um 40V process


• Hebistor clamps

– TSMC 0.25um

– Holding voltage tuning

– Low DC leakage

▪ <10nA at 25° C

▪ <150nA at 125° C

0

0.5

1

1.5

2

2.5

3

3.5

0 10 20 30 40 50 60 70

I [A]

V [V]

Example: High Voltage/BCD – Industrial CAN


• Bi-directional Industrial CAN clamp

– Includes specs for

▪ IEC 61000-4-2

▪ ISO 7637-2

▪ IEC 62132 (DPI)

• All specs tested on test chip

→ Product passes all specs

SpecificationsSupply functional voltage range 4.5V to 5.5V

PIN functional voltage range -7V to 12V

Absolute ratings -36V to +40V

Leakage 1uA

Temperature range -40°C to 150°C

IEC 61000-4-2 8kV

HBM 10kV

MM 200V

CDM 1kV

DPI specification1MHz/21dBm-> 8MHz/39dBm8MHz/39dBm->90MHz/39dBm90MHz/39dBm->1GHz/33dBm

ISO 7637 - 2 Pulse 1 -100V

ISO 7637 - 2 Pulse 2a +75V

ISO 7637 - 2 Pulse 3a -150V

ISO 7637 - 2 Pulse 3b +100V

ISO 7637 - 2 Pulse 5 +40V

Vbd

Example


• TSMC 180nm BCD gen 2 technology

– ESD trigger voltage Vt1 = 24 V

– Clamping voltage Vh = 23.5 V

– IEC 61000-4-2 contact discharge 8kV

– Leakage at 25°C: 1nA

– Area: 37,000 um²

• Scaling to 2kV HBM version

– <5,000 um²

Example: Automotive LIN protection for TSMC 0.25um BCD

10

• Sofics’ LIN interface protection TSMC 0.25um BCD

– High ESD performance

▪ 16A TLP current (@ 48V)

▪ 24kV HBM

▪ 6kV IEC 61000-4-2 direct injection

– EOS tolerant

▪ Load dump pulse ISO 7637-2

▪ Tolerant above 40V

– Transient Latch-up immune

▪ High holding voltage

▪ At high temperature

▪ For fast events

0

2

4

6

8

10

12

14

16

0 10 20 30 40 50

I [A]

V [V]

SOFICS © 2021 Proprietary

Example: Automotive LIN example for TSMC 180nm BCD

11

• Sofics’ LIN interface protection:

– Bidirectional protection

– Positive side

▪ Vt1 > 50V

▪ Vh > 18V

– Negative side

▪ Vt1 < -27V

▪ Vh < -10V

– It2 > 18A

– IEC 61000-4-2

▪ Stand alone ESD protection clamp 8.3kV

▪ Inside LIN product >12kV


Example: Sofics solution for TSMC 180nm BCD

12

• Requirements for automotive SENT

– Single-Edge Nibble Transmission interface

– ESD requirements

▪ IEC 61000-4-2: up to 8kV with various RC

combinations at powered conditions

▪ ESD holding voltages: 20V & 40V

▪ Low resistance to internal connections

– Leakage current

▪ below 500nA at 150°C at Vdd bias

– Compliance to EMC standards

▪ IEC 62132-4 (DPI – 32dBm) and IEC 61967-4 -2

0

2

4

6

8

10

0 10 20 30 40 50 60 70

10-10

10-9

10-8

10-7

10-6

10-5

0.0001 0.001 0.01

I D

UT

(Am

ps)

V DUT(Volts)

I(SP LEAKAGE)


High voltage examples


Applications on TSMC 0.25um BCD Vt1 Vh ESD Specification Area

45V interface protection 54V 49V TLP > 3.5 AHBM > 5 kV

36,800 um²

Automotive interface protection 44V 27V

TLP > 3 AHBM > 4 kV

4,400 um²

IEC 61000.4.2 contact > 9 kV 15,500 um²

IEC 61000.4.2 contact > 13.5 kV 29,500 um²

Applications on UMC 0.18um BCD Vt1 Vh ESD Specification Area

18V domain protection 21V 20V TLP > 2 AHBM > 3 kV

5V protection 11V 8V TLP > 5.5 AHBM > 7 kV

26,000 um²

24V protection 29V 27V TLP > 5 AHBM > 6.5 kV

44,000 um²

High voltage examples


Applications on TSMC 0.18um BCD Vt1 Vh ESD Specification Area

18V domain protection 24V 23.5V TLP > 7 AIEC 61000.4.2 contact > 4 kV

33,450 um²

60V protection 66V 47V TLP > 1.4 AHBM > 2 kV

26,860 um²

Industrial CAN 58V 25V TLP > 9 AHBM > 10 kV

96,000 um²

Automotive LIN 50V 19V TLP > 18 AHBM > 8 kV

IEC 61000.4.2 contact > 10 kV

111,000 um²

65V domain protection 68 32 IEC 61000.4.2 > 4.8 kV 59,500 um²

68 50 IEC 61000.4.2 > 4.8 kV 67,500 um²

55V domain protection 57 32 IEC 61000.4.2 > 4.8 kV 57,000 um²

57 50 IEC 61000.4.2 > 4.8 kV 64,500 um²

Press releases: cooperation with Sofics

15

ANALOG DEVICES

• ESD Protection for 60V Products

“We need strong, sophisticated ESD

protection for 60V devices without

compromising the mixed signal performance

of the products”.

▪ David Robertson, vice president of analog

technology for Analog Devices.

ZMDI

• Automotive Requirements on 0.18um

“Sofics clamps were superior in the EMC test,

as well as in parameters such as meeting

flexible clamping voltage specifications, at a

lower cost than building the clamps from

scratch.”

▪ Frank Shulze, Business Line Manager,

Sensing and Automotive, ZMDI.




• Introduction




• Conclusions

Protection Devices - SCR device


• Main principle:

– Coupling of bipolar transistors creates regenerative action

– Large current conduction possible

N+ P+FOX

P+N+

Pad

G2 A C G1

Vss

NWell Psub

G1C

Qp1

Qn1

G2 A

Basic SCR: High trigger voltage


• Basic SCR has a high trigger voltage

– Nwell / Pwell breakdown voltage

– Highly Process dependent

– Vt1 > GOX breakdown

0

1

2

3

4

5

6

7

8

0 5 10 15 20 25 30 35

curr

en

t [A

]

voltage [V]

SCR

W=100um

L=3um (ACS)

well-to-well breakdown

Vhold Vt1

VDD BVox

SCR – Typical values


• Typical values for SCRs

– Imax = ~ 50 mA/um

▪ Example: 26um width required for 2kV HBM (~1300 mA)

– Vt1

▪ Basic SCR

– Process dependent (doping levels)

– Well-2-well breakdown, avalanching

– Example: Vt1 = 40V for 14V process

▪ LVTSCR

– N+/PWell breakdown, avalanching

– Example: Vt1 = 10V for 0.35um process

– Vh

▪ Function of the Anode - Cathode distance (‘LAC’)

▪ Typical value: Vh = 1.2V

I

V

Ron-1

Imax

Vh Vt1

Sofics SCR – overview of parameters – device


• TakeCharge SCR’s for ESD protection

– SCR Layout variations

▪ Device width

▪ Anode Cathode (A/C) distance

▪ Contact rows on A/C

▪ Nwell / Pwell structure

▪ A/C Segmentation

– Trigger element variations

▪ Diodes, Bipolar, MOS, …

– ESD Detection variations

▪ Static Voltage, Current level

▪ Supply state detection

▪ Dynamic Voltage, Current change

DTSCR RCSCR

Sofics SCR – summary


• Tunable trigger voltage Vt1

– Determined by the external trigger element

– Different options available

Voltage

Current

Vhold Vt1

SCR

Damage

of

IO

or core

Vmax

It2Imax

RON

Vdd +10%

0

1

2

3

4

5

0 20 40 60 80 100

I [A]

WSCR

[um]

W=2x22>2kV HBM>200V MM

Sofics SCR – Tunable failure current It2


• Tunable Failure current It2, Imax

– Any ESD specification possible

– Determined by the SCR A/C width and # contact rows on A/C

– Example: DTSCR

Voltage

Current

Vhold Vt1

SCR

Damage

of

IO

or core

Vmax

It2Imax

RON

Vdd +10%

Scaling to higher ESD levels – example 1.2V


• Cells designed for different ESD levels

– Diode triggered SCR

– Reverse diode included

– 2A TLP – 2.8kV HBM

▪ Area: 35um x 22um = 770 um²

– 3.6A TLP – 5kV HBM

▪ Area: 35um x 38um = 1330 um²

– 7A TLP – 10kV HBM

▪ Area: 60um x 40um = 2400 um²

– 8kV IEC 61000-4-2

▪ Area: 120um x 54um = 6480 um²

– 12kV IEC 61000-4-2

▪ Area: 175um x 54um = 9450 um²

Process technology: 65nm

Example data for BCD processes


• SCR based ESD protection for high voltage interfaces

– All cases

▪ Leakage less than 10nA

▪ ESD performance of 4kV HBM

– 5V application

▪ Area of 2500 um²

– 10V application


– 15V application


– Area variation: depends on selection of suitable trigger element with right breakdown voltage

Trigger element



• Introduction


• Conclusions

Sofics solutions for BCD applications


• Broad set available

– Low clamping voltage, based on SCRs

▪ Mainly for interface protection

▪ Customizable through layout

▪ Small area, low leakage

– High clamping voltage, based on proprietary device concepts

▪ Mainly for power domain protection

▪ Of for automotive interfaces that need high transient latch-up immunity

• Standard process compatible

– No need for process changes, no need for additional masks/implants

FABLESS SOFICS SOLUTIONS FOR BCD PROCESSES

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