Fast Vacuum for Optical Disc Metallization and ...

Fast Vacuum for Optical Disc Metallization

and Photovoltaic Coatings

B. Cord, M. Hoffmann, O. Hohn, F. Martin

SINGULUS Technologies AG, Kahl am Main

SINGULUS

TECHNOLOGIES

June 2014

SINGULUS TECHNOLOGIES AG

25-June-2014 - 2 -

PTB, Workshop on Vacuum Metrology, June 25th 2014

SINGULUS Overview

Replication CD, DVD, Blu-ray Vacuum (UHV) Multi-Layer Deposition Vacuum coating,

Thermal Treatment,

Chemistry


25-June-2014 - 3 -


Content

Optical Disc: Dynamic Vacuum at Metallization

Pirani-, Diaphragm-, Ion-Gauges

Photovoltaics: Process Pressure Measurement for

Plasma Enhanced Chemical Vapour Deposition

(PE-CVD)

Capacitance (Diaphragm) Gauges


25-June-2014 - 4 -


BD-Dual Layer (50GB)

PC-Disc: 1.1 mm

Reflector L0: 35 nm Ag (<60%R<85%)

Laquer: 72 μm

Moisture Barrier: 10 nm SiN

Laquer Hardcoat: 3 µm

Laquer: 25 μm

Semi Reflector L1: 25 nm Ag (<18%R<30%)

Optical Disc Blu-ray ROM

Fully Automated Production: CD, DVD and Blu-ray

Vacuum

(Sputtering)


25-June-2014 - 5 -


Single Station Magnetron Sputtering System

Cycletime 1,5 - 4,5s

CD-Metallizer SINGULUS

Sputter Station:

- Gassupply Ar

- Turbomolecularpump

- Ion gauge

(10-4 to 1 Pa)

Small volume Loadlock:

- Volume about 100ccm

- Prepump of about 20cbm/h

- Piranitype vacuumsensor

(1 to 10+5 Pa)

DVD-System Spaceline BD-System BLULINE

Turntable:

- Rotation 180° and

- Up and down


25-June-2014 - 6 -


BLULINE: Vacuum Layout

Process chamber vacuum:

(turbomolecular pump,

ion gauge)

10-8Pa base pressure

Loadlock:

(prepump, Pirani Gauge in

pump line):

Setting of pumpdown

threshold (in mV of gauge

reading)

Display of evacuation time

(ms)

500ms = 1mbar (= 6200mV) Prepump

Loadlock

Venting

Loadlock

Pumping

Process

Chamber

Vacuum Schematics: Loadlock and process chamber


25-June-2014 - 7 -


Metallizer: Dynamic Vacuum in Load lock

Opening of pump valve Closing of pump valve

Threshold

vacuum trigger:

45 Pa

Load lock: Pump down

Base pressure pump


25-June-2014 - 8 -


Metallizer: Dynamic Vacuum in Load lock

Opening of pump valve Closing of pump valve

Threshold

vacuum trigger:

45, 100, 200, 500 Pa

Load lock: Pump down


25-June-2014 - 9 -


Metallizer: Dynamic Vacuum in Loadlock

Process chamber:

Bayard Alpert Gauge

Load lock:

Pirani Gauge

Start pump down

Load lock

Closing of pump valve and

opening of load lock

to process chamber

Loadlock: Pumpdown; Pressure burst into Process chamber

Pressure

burst Closing of load lock

to process chamber

2s


25-June-2014 - 10 -


Metallizer: Dynamic Vacuum in Process Chamber

Opening of load lock

to process chamber

(different thresholds)

Process chamber:

(one TMP)

Process chamber:

(two TMP’s)


25-June-2014 - 11 -


Metallizer: Dynamic Vacuum in

Process Chamber with Argon gas

Gauges:

Pirani Bayard Alpert Ion Gauge

Argon gas

Air from

load lock

Plurality of gauges

at DN25 cross

Dynamic behaviour of different gauges


25-June-2014 - 12 -


BLULINE: Dynamic Vacuum in Load lock

Pirani Gauge in pumpline

Additional Pirani gauge at loadlock

(for experiment only) Loadlock vented

Start pump down

Late reaction of Pirani

after start pumpdown

Pirani: Dynamic behaviour at high Pressures (>1000Pa)

Base pressure pump


25-June-2014 - 13 -


Loadlock: Dynamic Vacuum Measurement

Start pump down

(opening of valve)

Pirani /Diaphragm gauge

bottom of load lock

Pirani/Diaphragm

gauge top of load lock

Pirani

gauge top of

load lock

Late reaction of

Pirani after start

pump down

Pirani: Study of Dynamic behaviour at high Pressures (>1000Pa);

Comparison to combined Pirani/Diaphragm


25-June-2014 - 14 -


Loadlock: Dynamic Vacuum Measurement

Slow venting

Fast venting

Pirani: Study of Dynamic behaviour at high Pressures (>1000Pa);

Comparison to combined Pirani/Diaphragm

Pirani

Pirani

Combined

Pirani/Diaphragm

Combined

Pirani/Diaphragm


25-June-2014 - 15 -


Optical Discs: Pirani – Diaphragm – Ion

Gauges

Summary of Gauges for rough and high vacuum

Pirani: Gauge of choice for 100Pa level with good time resolution

Pirani shows large deviations for dynamic vacuum measurement

at levels of >1000Pa

Combined Pirani/Diaphragm gauge good solution up to 1000hPa

Ion gauges seem to be fastest

Absolute, precise pressure measurement with ion gauges

needs careful integration and calibration


25-June-2014 - 16 -


Photovoltaics: Coating of Si-wafer with Si-Nitride

→ SINGULAR multi chamber coating tool

→ Inductively coupled plasma source

→ Deposition by Plasma assisted

chemical vapor deposition (PECVD)

→ Process gases like NH3, SiH4, N2, ….

→ Modular design for various processes

(e.g. SiNx, AlOx, a-Si)

Four identical PECVD

Process stations


25-June-2014 - 17 -


TECHNOLOGY: ICP - PECVD

Process pressure

Measurement:

Direct Pressure gauges

(Diaphragm, Capacitance)

Pressure Measurement of Process gases for PECVD:

• Usage of gas independent sensors (Diaphragm Capacitance Gauges)

• Range 0,01 to 100 Pa

• Avoid decomposition of gases at hot filaments (no ion gauges)

• Issue of sensor contaminations

Plasma chamber Substrate

Pump


25-June-2014 - 18 -


TECHNOLOGY: ICP - PECVD

SiH4 NH3

Additional Gas

Valves

Plasma: Inductively coupled plasma (ICP)

Vacuum: 0,01 to 100 Pa

Static SiNx Process:

Process on 9s, transport 3s with no gas

going into chamber (avoid chamber

crosscontamination)

Flowcontroller

Gas Valves


25-June-2014 - 19 -


Photovoltaics: PECVD Stations

with Capacitance Gauges

Different

SiH4 Flows

Topic: Actual pressure in chamber after gasflow switching

Pressures SiH4

Pressures NH3

Flows NH3

Flowmeter on

Valve opening

SINGULAR:

Pressures in Chamber without plasma

Flowmeter on


25-June-2014 - 20 -




SINGULAR Machine#1:

Pressure versus Flow relation:

- Measurement at four stations

- Machine to machine comparison

SiH4

NH3

Topic: Station to station comparison of process pressure

at identical gas flows


25-June-2014 - 21 -




SINGULAR Machine#2:

Pressure versus Flow relation:

Measurement at four stations

SiH4

NH3

Pressure Deviation

at Station 4 (No#2)

Topic: Station to station comparison of process pressure



25-June-2014 - 22 -




SINGULAR Machine #1 and #2:

Comparison SiH4

NH3

Precise and stable pressure

measurement over time and

from sensor to sensor required

Topic: Machine to machine comparison of process pressure



25-June-2014 - 23 -




SINGULAR

Pressures in Chamber without plasma

Different gas

valve

opening times

Topic: Actual pressure in chamber after gasflow switching

Optimizing the gas inlet

for shortest pressure

stabilization time


25-June-2014 - 24 -




Summary Capacitance Gauges for PECVD

Accuracy of absolute pressure measurement good (but not perfect)

Often zeroing of gauge required

Signal rise/fall times in the range of some hundred milliseconds,

but difficult to judge due to gas filling times for the vacuum

chamber


25-June-2014 - 25 -


Question:

Operation of the Capacitance Gauges:

Absolute pressure accuracy over time?

What is best routine for the often required zeroing?

Thanks for your attention

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Fast Vacuum for Optical Disc Metallization and ...

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