polymer tantalum capacitors for advanced high reliability ... day/new... · why hermetical...

©2014 AVX CONFIDENTIAL 1

Polymer Tantalum Capacitors for Advanced High Reliability Applications

J.Petržílek, M. Uher, J. Navrátil, M.Biler

AVX Czech Republic s.r.o., Dvorakova 328, 563 01 Lanskroun, Czech Republic Tel.: +420 465 358 126 e-mail:[email protected]

2 QRTS INTERNATIONAL 2015 SPCD 2016

Tantalum Capacitors – Dielectric Contacting

Liquid electrolyte MnO2 Polymer

WET Tantalums ionic conduction hermetically sealed + surge robust + high voltage + high temperature - temperature dependent - frequency dependent - electrolyte leak possible

Solid - MnO2 electronic conduction + high temperature + well established reliability - failure mode - voltage limited - ESR higher

Solid - Polymer electronic conduction + low ESR + safe failure mode + high voltage - temperature limited - humidity & oxygen sensitive


Hermetically Sealed Polymer Capacitor

Ta capacitor with polymer Why Hermetical Packaging Thin cathode layers under extreme condition are subject of potential degradation

TCH Series Hermetic seal: Protects from degradation by humidity Protects from degradation by oxidation

Stable low ESR Stable parts under extreme conditions

Solution developed with ESA partnership


optimized anode with robust dielectric

pre-polymerized PEDT based cathode material

use of special ageing and screening processes

hermetic seal, inert atmosphere

parallel connection of multiple capacitors

high voltage potential up to 100 – 125V

High Voltage Low ESR Polymer Capacitor

Basic concept

low ESR potential


Robust Mechanical Design

Mechanical Test Method Reference Result Shock 100g (MIL-STD-202, Method 213, Condition C) PASS Vibration 20g (MIL-STD-202, Method 204, Condition D) PASS PIND 20g (MIL-STD-883, Method 2020, Condition A) PASS

ceramic case anode wire welded to leadframe leadframe welded to internal contacts internal filler applied inert dry atmosphere metal lid welded undertab or L-shape J lead


Ageing and Screening Procedures

20151050

99.9

99

959080706050403020105

1

0.1

DCL at 90% of formation voltage [uA]

Per

cen

t

arbitrary limit

3xSD limit

Every capacitor is stressed by voltage

Statistical approach applied to removal of weaker parts

Final capacitors are aged 168h

100V rated voltage capacitor

Screening before assembling


1001010.1

350

300

250

200

150

100

50

0

time [hours]

Cas

e te

mpe

ratu

re [

°C]

Internal Filler Influence on Highly Accelerated Ripple Current Life

Air

Nitrogen

syntactic foam powder encapsulant

heat conductive sillicone

sillicone

heat conductive and inert material increases life under high power conditions

Measurement conditions: TCH 9 22µF 100V external ambient temperature 10V DC bias 20 kHz, 8A AC case filled by gas or solid material


Moisture Influence on Capacitance

1258525-55-196

65

60

55

50

45

40

1258525-55-196

K

T [C]

Cap

[uF

]Sstandard cathode experimental cathode

WETSTD

DRY

nominal capacitance 47uF

capacitance retained up to -196 ºC humidity increases cap cathode modification can increase

dry capacitance

parts before final sealing: humidified WET not conditioned STD dried DRY


Moisture Influence on DCL

DCL measurement at temperatures (22uF/ 100V)

604530150

1000

100

10

1

0.1

0.01

604530150

open

t [min]

I [u

A]

sealed

25°C

85°C

125°C125°C

25°C

lid open = traces of water in

cathode

sealed = dry

fast DCL stabilization for open case or closed case and elevated temperatures


Moisture Influence on DCL

403020100

0.01

0.001

0.0001

0.00001

403020100

23

U [V]

I [m

A]

125

DRY

WET

STD

°C °C

dry unit at low temperature has steeper characteristics how is this DCL related to its stability under accelerated conditions?

V/I measurement by 1V/80s parts before final sealing: humidified WET not conditioned STD dried DRY


Moisture Influence on DCL Stability

2000150010005000

100

10

1

0.1

0.01

0.001

0.0001

2000150010005000

2000150010005000

dry

Time [hrs]

DC

L at

35V

/125

°C [

mA

]

STD wetdried

before sealing humidified

before sealing

stable DCL

increasing DCL

failures

Highly accelerated life test (2.1x recommended voltage/ 125ºC)

not conditioned before sealing


Stability of Hermetically Sealed Capacitors

20000150001000050000

100

75

50

25

0

t[h]

CA

P[u

F]

20000150001000050000

100

75

50

25

0

t[h]

20000150001000050000

0.100

0.075

0.050

0.025

0.000

t[h]

ESR

[Ohm

]

20000150001000050000

0.100

0.075

0.050

0.025

0.000

t[h]

T[°C ] = 85; Utest = Ur T[°C ] = 125; Utest = Ur

Stability of capacitance and ESR 35V rated voltage capacitor (100uF)

Stable Performance


Challenges – super low ESR - Modular Solution

TCH 9 case 22µF/ 100V ESR 60 mOhm Customized case

400µF/ 100V ESR 3 mOhm

TO3 case 100µF/ 100V ESR 9 mOhm

Multiple capacitors connected in parallel Capacitace high ESR low


Challenges – super low ESR - Modular Solution

400µF/ 100V

Capacitace stable with temperature and frequency


1600012000800040000

20

15

10

5

0

t[h]

CA

P[u

F]

100007500500025000

20

15

10

5

0

t[h]2000150010005000

20

15

10

5

0

t[h]14001100800500200

20

15

10

5

0

t[h]

1600012000800040000

0.20

0.15

0.10

0.05

0.00

t[h]

ES

R[O

hm

]

100007500500025000

0.20

0.15

0.10

0.05

0.00

t[h]2000150010005000

0.20

0.15

0.10

0.05

0.00

t[h]14001100800500200

0.20

0.15

0.10

0.05

0.00

t[h]

U [V] = 100 V; T [°C] = 85 °C U [V] = 67 V; T [°C] = 125 °C U [V] = 50 V; T [°C] = 150 °C U [V] = 0 V; T [°C] = 175 °C

U [V] = 100 V; T [°C] = 85 °C U [V] = 67 V; T [°C] = 125 °C U [V] = 50 V; T [°C] = 150 °C U [V] = 0 V; T [°C] = 175 °C

Challenges – Higher Temperature

Stability of capacitance and ESR 100V rated voltage capacitor (22uF)

Almost stable performance above 125ºC

150ºC 175ºC


Challenges – Higher Voltage

Extremely High Voltage Ta Polymer Capacitors TCH 9 10uF/175V


■ stable performance and reliability exceeding 10,000 hours, 85°C at Vr, 125°C at 0.66xVr

■ up to 100V rated voltages (22uF in CTC21D size) ■ lightweight solution typically 2.2g per CTC21D size ■ ESCC evaluation under progress

Summary & Conclusion

Hermetically Sealed Low ESR high voltage high Reliability Tantalum Capacitors

■ higher temperatures: 150°C at 0.5xVr released soon ■ very low ESR, high voltage, high ripple current modular solution ■ higher voltages up to 175V

Potential for

polymer tantalum capacitors for advanced high reliability ... day/new... · why hermetical...

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