0. Table of contents - hitech-projects.com STS CPX Operating Procedure ... Instruction and test ......

Document nr. : MarRag-20130306-01V04 Page nr. : 0

Document : Operation Manual STS CPX Epcode : E28

Administrator : Documents Administrator TFF Date: 06-03-2013

© Philips Research – MiPlaza/TL Company Restricted Operation manual STS CPX V03

Author: Maria Filomena Raganato

0. Table of contents

0. Table of contents .............................................................................................................. 0 1. Changes compared to previous versions .......................................................................... 1 2. Safety ................................................................................................................................ 2

2.1 Gasses ......................................................................................................................... 2 2.2 Radio Frequency (RF) Power ..................................................................................... 3

2.3 UV Hazard .................................................................................................................. 3

2.4 Temperature Hazard ................................................................................................... 3

2.5 Safety Features ........................................................................................................... 3 2.6 Magnetic Fields .......................................................................................................... 3

3. General information ......................................................................................................... 4 3.1 APS (Advanced Planar Source) module ..................................................................... 4

3.2 ICP module ................................................................................................................. 5 3.3 Pegasus module .......................................................................................................... 6

4. Operation manual ............................................................................................................. 9

4.1 STS CPX Operating Procedure .................................................................................. 9 4.2 Verity endpoint detection Operating Procedure ....................................................... 14

5. Process Control .............................................................................................................. 16 5.1 Aborting the process ................................................................................................. 16 5.2 Errors during processing ........................................................................................... 16

6. Rules & Regulations ...................................................................................................... 17

7. Instruction and test ......................................................................................................... 18



Administrator : Documents Administrator TFF Date : 06-03-2013


1. Changes compared to previous versions

Date Page

number

New ver-

sion num-

ber

Description

09-12-2010 V01 First version with Document number

22-05-2012 V02 Second version with new rules about

the tool reservation

25-10-2012 V03 Third version with new rules about

who can have authorization on this

tool.

06-03-2013 V04 New rules about how protect the edge

of the wafers during the process in

order to prevent particles problems





2. Safety

2.1 Gasses

The STS CPX is a three chambers cluster tool equipped with hazardous and non hazardous

gasses. The system is designed to operate at negative pressures, consequently any leaks will

usually be „in to‟ not „out of‟ the system. The leaking gasses will therefore be pumped away

by the pumping system to the exhaust.

An over-pressure switch is used as a safety interlock in the 24 V DC supply to the gas box

solenoid. If the pressure exceeds 3.7 Torr, the pressure switch operates cutting off the gas

supply to the process module. It operates in a fail-safe mode.

The table below shows the gasses attached to the chambers (APS, ICP and PEGASUS).

Module Gas Max flow rate [sccm]

APS C4F8 100

APS SF6 100

APS O2 100

APS N2 100

APS Ar 100

APS He 500

APS CF4 100

APS CHF3 100

APS H2 100

ICP SF6 100

ICP O2 100

ICP N2 100

ICP Ar 100

ICP He 100

ICP CF4 100

ICP CHF3 100

ICP Cl2 100

ICP HBr 100

ICP BCl3 100

PEGASUS C4F8 400

PEGASUS SF6 1200

PEGASUS O2 200

PEGASUS Ar 200

PEGASUS N2 200 Table 1: gases that are being used in the STS CPX

Detailed information about these chemicals can be found in the corresponding Material Safety

Data Sheets (MSDS).





2.2 Radio Frequency (RF) Power

The system uses RF power during processing. All enclosures which RF power is present are

clearly marked and the covers are fitted with electrical interlocks. Anyone requiring access to

the source must be fully aware of the hazards of RF power.

The relevant parts of the system must be electrically isolated before any work is carried out

inside these enclosures. Apart from the risk of electrical shock, severe burns are possible if

live conductors are touched.

2.3 UV Hazard

Gas plasmas produce ultraviolet (UV) rays that can cause severe skin and eye burns. Don‟t look

into the plasma when the viewport is not UV filter marked. In general all the viewports should be

UV filter fitted except the EPD port.

2.4 Temperature Hazard

The process chambers are temperature controlled, in different zones, up to 140 ºC. Be aware

that substrates can be at elevated/ reduced temperatures after processing.

2.5 Safety Features

The system uses several software and hardware interlocks to protect against hazardous inter-

ference to the system. The software interlocks will prevent processing should certain moni-

tored parameters not be met. When either a software or hardware interlock failure occurs, the

software will display an interlock error message detailing the exact interlock failure.

There are two mechanical interlock circuits on the system:

1. Gas interlocks: Disables the system gas lines in the event of a fault or if the

interlock chain is not complete.

2. RF interlocks: Disables the RF generators in the event of a fault or if the

interlock chain is not complete.

2.6 Magnetic Fields

The source contains strong magnetic fields. Strong magnetic fields may cause pacemakers to

malfunction. Damage to magnetic-sensitive devices (bank/credit cards, watches, etc.) may

also result. Magnetic field strength is negligible at distances over 30 cm from the source.





3. General information

The STS CPX (E28) is a dry etch cluster tool. The system consists of a Brooks Marathon Ex-

press® 600 (MX600) handler, APS process module, ICP process module and a PEGASUS

process module.

The Brooks transport module (TM) consists of a core module which can service up to four

Process modules (PMs). The TM also includes an integrated substrate flat aligner, two Va-

cuum Cassette Elevators (VCE‟s) and a single ended Brooks Mag Tran® 7 robot in Frogleg

configuration. Mag Tran® 7 robots represents Brooks Automation's most advanced and relia-

ble robot for in vacuum operation. The arm provides the best handling accuracy and repeata-

bility, and as standard comes with Kalrez pads on the endeffector to allow maximum 0.3g

acceleration profile. The 0.3g acceleration is only guaranteed on standard SEMI defined sub-

strates. For non-standard substrates such as heavier, polished, unbalanced, carriers etc. slower

arm acceleration maybe recommended.

Figure 1

3.1 APS (Advanced Planar Source) module

The APS process module was designed to offer high etch rates for more physical (ion driven)

processes such as the etching of SiO2. The platform is configured with a 2000 l/s turbo mole-

cular pump and a 3 kW RF power supply for powering the source coil in order to maximize

gas species for reactive ion etching.

The APS plasma source has been specifically developed to overcome the problems of etching

hard materials such as oxide, observed in other high-density plasma systems. It is a patented

source design that employs many advanced features. A schematic representation of the APS

source (Figure 2) is presented below. The antenna arrangement is such that for the multi turn

coil the different turns are situated above each other i.e. helical in form. A particular advan-

tage of the design is that the dielectric window through which RF power is coupled from the

antenna into the plasma is carefully shaped to maximize the coupling of power.





Figure 2

The APS source design incorporates multi-polar magnetic confinement and heating of the

chamber walls. These features help to minimize deposition on the process chamber walls and

thus enhance system cleanliness, thus increasing process stability and increasing the time be-

tween the requirements to clean the process chamber. The “magnetic bucket” is formed from

small permanent magnets which improves plasma confinement and therefore increases the

number of ions that can reach the wafer.

The multi turn ICP coil is DI water cooled and capable of handling high powers (up to 3 kW).

A 13.56 MHz RF supply and automatic matching network is employed. A patented balanced

feed arrangement is used to drive the coil i.e. RF potential is applied to both ends of the coil

rather than one end being driven and the other end grounded. This provides a highly uniform

electric field around the circumference of the coil, and hence an excellent plasma density un-

iformity. The doughnut shaped dielectric window is made from fused Al203. The coil fixtures

allow exact positioning of the coil within the ceramic whilst insuring that disassembly and

assembly of the source for maintenance is very simple. The process gas is distributed through

a pair of baffled showerheads positioned both within and around the coil, in order to ensure

excellent gas distribution to the plasma.

3.2 ICP module

The ICP process module (Figure 3) produces high plasma densities at low pressure with ex-

ceptional uniformity. The STS ICP offers a robust solution to producing high density plas-

ma's. Compared with alternative technologies, such as Electron Cyclotron Resonance (ECR),

ICP provides the user with a simple, reliable, and easily maintained system that is very easy to

operate. At the same time, ICP offers exceptional process capability, including: high etch

rates, excellent etch uniformity, improved selectivity over common masking materials and the

ability to etch smaller critical dimensions and higher aspect ratios compared with more tradi-

tional planar diode Reactive Ion Etch (RIE) Systems.





Figure 3

The ceramic vessel that forms the main part of the process chamber and dielectric window of

the ICP source is made of a single, 13mm thick, piece of fused alumina (Al203). This signifi-

cantly improves the reliability and lifetime of the ICP source compared with using a quartz

window. The vacuum seal between the bottom of the ceramic vessel and the lower chamber

block is a Viton “o” ring. The ICP source electrode is a robust, single turn, copper coil that is

concentric with the dielectric window (often referred to as a cylindrical dielectric window or

CDW design). The RF potential is applied using a patented balanced feed arrangement, i.e.

RF potential is applied to both ends of the coil rather than one end being driven and the other

end grounded. This provides a highly uniform electric field around the circumference of the

coil, and hence an excellent plasma density uniformity. The coil fixtures allow exact position-

ing of the coil around the ceramic whilst insuring that disassembly and assembly of the source

for maintenance is very simple. The source is air cooled, and the distance between the center

of the coil and the wafer surface can be set between 40 mm and > 130 mm (simple mechani-

cal adjustment). The ability to process wafers at increased separation from the coil (and hence

highest plasma density regime) is important since it can help improve etch uniformity and

reduce the ion density at the wafer surface. This can help to improve mask selectivity and also

reduce the risk of damage to active devices on the wafer.

3.3 Pegasus module

Pegasus represents the markets leading Deep Reactive Ion Etch (DRIE) processing system

providing production customers the fastest etch rates with exacting feature profile control and

excellent uniformity for substrate sizes up to 200mm in applications requiring deep anisotrop-

ic etching. This combination of benefits further reduces the cost in volume applications such

as MEMS device production in Silicon using STS' ASE processing technology. Pegasus uti-

lizes an inductively decoupled plasma (DCP) source for high rate single wafer etching, confi-

gured as standard with electrostatic clamping. The MESC-compatible module may be sup-





plied with any of STS‟ handling platforms from vacuum single wafer loading to cluster va-

cuum cassette to cassette operation.

Figure 4





Low notching Silicon On Insulator (SOI) capability come as standard.

STS' patented Silicon On Insulator (SOI) system upgrade (US Patent No 6,187,685) controls

the interface charging effect that leads to notching when etching silicon to buried insulating

layers. The notching is an inherent problem in this process, since to allow all etch fronts in

both small and large features to reach the interface, an over-etch must be used. It is during this

over-etch that extensive undercutting in large features, which have already reached the inter-

face, can lead to device fracture. SOI decreases the sensitivity of the process to over-etch,

permitting more than 100% increase in overetch time, and virtually notch-free structures.

Eliminate notching at the insulator interface for a large number of applications

Increase the range of feature sizes that it is possible to etch successfully on one wafer

ASE Advanced software control features

STS has continually developed the Advanced Silicon (ASE ) process including patented soft-

ware parameter control. The Pegasus process module includes these ASE process related fea-

tures as standard.





4. Operation manual

4.1 STS CPX Operating Procedure

1. The system is equipped with a touch screen and keyboard. If the screen saver is active

touch the touch screen or keyboard.

2. The mimic screen (Figure 5) should appear. The mimic screen consists of a Title Panel,

Command Panel, Information Panel, Navigation Sub-Panel and a Navigation Panel

3. In the Tile Panel the current login status can be found. This should be “Logged Out” as

after the system has been used the operator should log off.

4. Press “logged out” and the login box will popup (Figure 6). Select others and enter the

login name and password. The login status is now changed (Figure 7).

Figure 6 Login screen

Title

Panel

Information

Panel

Navigation

Sub- Panel

Navigation

Panel

Command

Panel

Figure 5 Mimic screen explanation





Figure 7 logged in

5. By pressing the “Manual” button in the Navigation Panel the system overview will appear

when the “Transport Module” tab is selected (Figure 8).

Figure 8 Transport Module

6. At the right side of the screen, in the Operations tab, buttons are present to operate the two

Vacuum Cassette Elevator (VCE) stations. The buttons are white ready for use or grey

can‟t be used. The explanation of these buttons can be found in table 2.

Button Description

Pump Cassette Pumps the cassette to vacuum.

Vent Cassette Vents the cassette to atmosphere.

Open Cassette door Opens the cassette door, moving the VCE platform to the unload

position if possible.

Close Cassette door Closes the cassette door.

Load Cassette When the load button is pressed the Transport Module Controller

checks for the status of the transport module hardware and requests

the operator to load the cassette, name the cassette (if required) and

pumps the load lock down. The system then maps the cassette.

Unload Cassette When the unload button is pressed the system vents the load lock to

atmosphere and opens the door.

Map Cassette Scans the cassette for available substrates. Table 2





7. The system has 2 VCE‟s and two dedicated labeled cassettes. One cassette for the left and

one for the right VCE. Load the substrates in the cassette, put the cassette correctly on the

VCE platform and press the ”Load Cassette” button for the right cassette in the Operation

tab. Confirm the message Click here to confirm that the cassette 1 or 2 VCE door can

close in the Title Panel. The VCE is going to be pumped down and the substrates are

mapped.

Figure 9 Recipe Screen

8. By pressing the “Recipe” button the recipe screen is shown (Figure 9). In the left part of

the screen the folders of the different process modules can be found. The actual recipes

are located in the “Process Module” folder. The recipe consists of different steps like

“Clamp substrate”, “Leak up test” and “Main etch” (Figure10).

Figure 10 Main etch section

9. Select the “Main etch” and change the Process Time to the desired setting and confirm

this with the “Apply” button in the Command Panel. This is the only parameter that the





operator is allowed to change. The other settings can be found in the “Pressure”, the

“Generator” and the “Temperature” tab.

10. Return to the “Navigation Panel” by selecting the “Manual” and, if necessary, the “Trans-

port Module” button (Figure 8). Select the substrate that has to be etched followed by the

module to be used by selecting its chuck. In the command panel the selection that was

made is shown in the Substrate Transfer section (Figure 11) “From:” the substrate that

was selected “To:” the module that was selected. Press the Substrate Transfer “Start” but-

ton, if the right selection was made, and the wafer will be transferred via the aligner to the

selected process module. In the same way wafers are transported to other chambers, slots

or cassettes.

Figure 11 Substrate transfer

11. Select the process modules tab where the substrate is transferred to (“Process Module

(APS1)”; “Process Module (ICP2)”; “Process Module (PEG3)”) and fig. 13, 14 or 15 will

appear. This is an overview of the available resources of the selected module. Gas flows,

pressures, powers, etc. can be found in this screen. At the right side of the screen the

processing tab can be found.

Figure 12 Process Recipe start button

Select, when the substrate has transferred, in the Processing tab the right recipe from the

process list. If endpoint detection is desired the verity SD1024 endpoint should be standby

before pressing the “Start” button (Figure 12). For more information about how to operate

the endpoint detection go to the Verity endpoint detection Operating Procedure.





Figure 15 Process Module (PEG3)

12. Go back to the “Transport Module” tab via the “Manual” button in the Navigation Panel

and select the substrate followed by the cassette slot where it has to go too. Press the

“Start” button in the Substrate Transfer section (Figure 11) and the substrate moves to the

selected cassette slot. When all substrates are processed push the “Unload Cassette” but-

ton in the Command Panel and the VCE will vent and the door opens automatically.

13. Remove the substrates from the cassette, put the cassette back in the VCE, close the door

and Log out by pressing the Log in name.

Figure 14 Process Module (ICP) Figure 13 Process Module (APS)





4.2 Verity endpoint detection Operating Procedure

1. On the left hand side, next to the STS CPX touch screen the Verity 1024D endpoint

detection touch screen can be found. Each Process Module of the STS CPX has its

own endpoint program. SpectraView1 for the APS module, SpectraView2 for the IPC

module, SpectraView3 for the Pegasus module. The endpoint detection is not linked to

the STS operating software and therefore operates stand alone. Open the required pro-

gram via its shortcut on the desktop (Figure 16) or select the right window when the

program is already opened.

Figure 16 Verity 1024D desktop

2. The endpoint recipes can be found in the Configuration Panel on the left side of the

SpectraView window (Figure 17).

Figure 17 SpectraView





3. Endpoint recipes are selected by placing the mouse cursor on the correct endpoint pro-

gram and press the right mouse button. Select “Set as current” from the pop-up menu

(Figure 17) and the endpoint program has been changed.

Figure 18 Endpoint program selection

4. The endpoint detection is now standby. When the process on the STS CPX is started

and the plasma ignites the or starts the endpoint curve. By selecting the pause

or stop button the endpoint can either be stopped or paused.

The Monitor state graphically displays real-time spectra in Spectral Graphs

and trends in Trend Graphs without saving the data.

The Capture state does everything that the Monitor state does, and saves the

spectral data and the corresponding SpectraView configuration to a file.





5. Process Control

5.1 Aborting the process

The process can be stopped by pressing the abort button in the Processing tab (Figure 19). The

process will stop immediately after the “Abort” button is pressed. If it‟s not clear the “Pause”

button is another option. All the parameters are paused and, after a stabilization period, reacti-

vated with the resume button.

Figure 19 Process Abort

5.2 Errors during processing

Whenever there are ERRORS or uncertainties occurring during processing of substrates,

please contact the machine owner or back-up. Equipment ERRORS are made visual by red

blinking of the alarm button in the Navigation Panel (Figure 20).

Figure 20 Alarm message





6. Rules & Regulations

Only 150 mm non damaged normal flat sized substrates are allowed on the STS CPX.

Substrates that can be handled by the system should have a “normal” flat otherwise the

substrates will have problems aligning.

Substrates have to be inspected before loading. Back sides should be clean and particle

free.

Glass wafers can be etched but the back side of the wafer should be metal (Al) coated in

order to get wafer clamping and optical detection by the aligner. Take in account that ac-

tive cooling is very ineffective in case of glass substrates.

Substrate edges should be clean and not damaged as the optical aligner may cause troubles

in attempts to align these wafers.

In order to prevent the etching of the edge during the process and consequently particles

problems in the chamber, please protect the edge of the wafers with oxide and/or extra

resist. This is mandatory in case of deep silicon etching process!

The substrate thicknesses may vary from 200 µm up to 2mm.

Check the amount of wafers after wafer mapping to be sure all the wafers are detected.

Thin wafers may not be detected.

Contact the tool owner when an error occurs.

Through wafer etching always has to be verified with the equipment owner or the backup.

Be aware that metal contamination is not allowed on this tool. Contact the equipment

owner or the backup to determine how to proceed when an etch stops on a metal layer.

Contact the equipment owner or the backup when pieces of substrates have to be

processed.

Cleanroom users can have authorization for the E28 only if they use the system regularly

(at least once a week), they are qualified enough and they pay at least 0.5 FTE. Students

are not allowed on this tool.

It is not allowed to make a reservation on the tool longer than 3 hours. In order to arrange

the tool time in a proper way, it would be appreciated if you contact first the equipment

owner.

If you need the tool for longer time than 3 hours, please contact the equipment owner, in

order to find a solution to meet all the requirements.

Contact the equipment owner or the backup in case of any uncertainties.





7. Instruction and test

The only person, who is allowed to give the instructions, is the equipment owner. Normally

the instruction will take about half an hour and will be given only after reading this manual.

First the major parts and possibilities of the machine will be explained. After this the com-

plete operating screen and the correct way to run a process will be explained on the basis of

the Operating Manual as described in chapter 4 including the Verity 1024D endpoint detec-

tion. Subsequently the new user will run a process, based upon a substrate of his/her own,

independently as a test.

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