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Applied Materials Precision 5000 Etcher, p5000etch

The Applied Materials Precision 5000 Etcher is a "cluster" tool, consisting of four, independently-controlled etch chamber modules which surround a central loadlock. Chambers A, B, and C are Magnetically-Enhanced Reactive Ion Etch (MERIE) systems, each equipped with optical endpoint detection to allow for more customized etching. The chamber configuration and system software allow control over a wide range of process parameters.

Picture and Location

 

Applied Materials P5000 Etcher

 

Background

 

Description: Plasma Etcher for semi-clean (not contaminated) metals (Al, W, Ti), silicon dioxide, silicon nitride and polysilicon.

Features:

Wafer Size -- 4 inch wafers only.  Although pieces can be attached to 4 inch carrier wafers it is not recommended.

Chambers -- Three separate chambers for etching;

  • Chamber A - Primarily designed for Al etching but will also etch Ti, TiN and W layers.
  • Chamber B - Primarily designed for etching SiO2 layers but will also etch silicon nitride layers.
  • Chamber C - Primarily designed for etching poly silicon layers but will also etch silicide (Ti and W) layers and silicon trenches of 10um or less.

Etcher Configuration

  • Chambers A, B and C are in the magnetically enhanced reactive ion etcher (MERIE) configuration. For etching MERIE means the following:
    1. The wafers are placed on an RF (13.56 MHz) powered electrode.
    2. The electrodes areas are asymmetric with the wafer electrode being smaller than the grounded counter electrode. This asymmetry means that a large dc bias voltage will develop on the wafer electrode and will result in high energy (100 to 600 eV) ion bombardment of the wafer surface.
    3. A magnetic B field (30 to 100 gauss) in applied parallel to the wafer surface. This B field increases the plasma density and rate of ion bombardment which both increase the rate and directionality of the etching. The B field is created by using two sets of orthagonal Helmholtz coils mounted on the outside of each of the three chambers. By using low frequency AC current supplies and controlling the phasing to the two sets of coils, a rotating B field is achieved.

Wafer Clamping – Unlike older etch systems where the wafer just sits on the electrode, chambers A, B and C use mechanical wafer clamping to increase wafer cooling. By using a combination of an edge wafer clamp and a vacuum edge seal, the space between the wafer backside and the electrode can be filled with low pressure (4 to 8 torr) helium which acts as a heat conductor. The result is that the wafer temperature stays close to the electrode temperature independent of applied rf power. This is important for process control since many aspects of plasma etching, such as profile shape, are temperature dependent.  Because the wafer clamp uses several very small "fingers" to press the outer rim of the wafer down onto the seal, it is essential to keep these fingertips clean to prevent cross-contamination which may adversely affect wafers or interfere with wafer handling in the system. Edge bead removal is recommended. 

NOTE: There have been issues of wafers sticking to the clamp at the de-clamping step (after etching) Several solutions have been suggested; increasing the EBR from 2mm to 5mm and holding the PUMP OUT Step to 120sec for chambers B and C.  Clamp sticking is not a issue in chamber A, as the clamp material is different.

Chemistry

  • Chamber A – Al etching is accomplished using a chlorine (Cl2 and BCl3) based chemistry. The etching gas for Al is Cl2. While BCl3 also supplies Cl, its main purpose is to remove the Al2O3 surface layer and to getter any oxidizing species from the gas. Both BCl3 and N2 help passivate the etched sidewalls and thus are important in profile control. SF6 may be added for etching W.
  • Chamber B – Oxide and nitride etching are accomplished using fluorine (CHF3) based chemistry. For the standard process the dominant gas is Ar and is used for its ion bombardment. CHF3 is used to supply CFx species, which attach to the surfaces and act as the etching precursors. CF4 is used to control the polymer deposition from the CFx species. This deposition needs to be balanced between giving good selectivity to underlying Si and slowing down the oxide etch rate. The polymer deposition also affects the sidewall slope.
  • Chamber C – Anisotropic poly etching is accomplished using a combination of Cl2 and HBr for both the main and overetch steps. Since this chemistry is relatively selective to oxide, a fluorine based etch step is normally done first to break through the surface oxide laver. To improve the selectivity to oxide in the overetch step, a small flow of O2 is often added.

 

 

How to get trained n the P5000etch: 

 

 

Please refer to the Training Calendar to sign up for the most convenient session.

 

 

Operating Procedures

 

This machine is capable of a very wide range of process parameters and wafer movement sequences. Some screens, and the parameters available on them, if used improperly, can cause loss of calibration, robot errors, file corruption, and many other problems, not t to mention the loss or breakage of your valuable samples.  Users are to use only the screens, operating instructions, and procedures described in this document, or as instructed by responsible staff.  If you are not absolutely sure of what you are doing, don't do it.

 

Coral Enabling

If the system is not enabled, an error will occur when the system tries to vent the loadlock, and no wafers can be loaded or unloaded. The Coral name to enable is "p5000etch".

 

Button Definitions

There are five buttons located to the right of the loading door. They perform the following functions:

  • Emergency Power Off (EPO): should be used only in dire emergencies as it may cause permanent damage to the turbo pumps.
  • Run: starts the program when the system is in auto mode, and required chambers are "ONLINE for Process"
  • Stop: stops all wafer movement operations. Any wafer(s) in the chambers being processed will be allowed to complete the recipe, but the wafer will remain in the chamber, after the etch process recipe has finished. The best time to press the STOP button is while a wafer is being etched; this will prevent the next wafer from being loaded into the etch chamber, and avoids stopping the robot with a wafer on the robot blade during a wafer transfer. Run, in this case, allows the wafer handler to restart the sequence. Note: The wafer handler will NOT restart by using the Run button, with a wafer remaining on the blade once the Stop button has been pressed. Operator must give instructions to either retrieve wafer or continue processing. See Recover from Stop Procedure.
  • Load: If needed chambers are "ONLINE for Process", control mode is in Auto, appropriate sequence & recipe(s) are specified, & wafer cassette is loaded onto load station, Load will clamp the cassette, close the door, load wafers into the machine, process them, and return them to the cassette.
  • Unload: If the control mode is in Auto, and a cassette is clamped on the load station, Unload opens the door and releases the cassette when it is flashing.

 

Standby Condition

The standby condition is the condition that you should both find the etcher in when you want to enable it and the condition you leave it in when you are done. Please use the Coral equipment reporting option to report any discrepancies you find.

  • screen: System => Control
    System state should be ‘MANUAL’, Serial Sequence Selection should be in 'green stripe mode', the Program select spaces for chambers A,B and C should be blank, Cassette A should be CLAMPED and the door should be CLOSED.
  • screen: Service => Vacuum Service
    Chambers available for use will be ‘ONLINE for Process’. Warning; chambers in ‘OFFLINE for Maintenance’ mode cannot be put in the ONLINE condition by users. Maintenance and Process staff only may change the chamber mode.
  • screen: Wafer => Monitor Wafer
    Blue cassette should empty and be placed on left side of load station (the ‘A’ position) and ‘CLAMPED’, and the outer plastic door should be ‘CLOSED’. Only use the A (left) side of the load station.

 

System Inspection and Operation

The following is a brief checklist to ensure machine is functional. The list is also the start of the operating procedures. Go through it every time you use the etcher.

  1. Is machine and process chamber(s) available for process? Check Coral (don't foget to look at Comments) and check to see there are no notes around the load station.
  2. Logon to p5000etch using light pen. Login/password = USER/USER.
  3. Enable ‘p5000etch’ using Coral.
  4. screen: Service => Vacuum Service
    Verify that the chambers which will be used are "ONLINE for Process". Chambers which are "OFFLINE for Maintenance" cannot be used because of failure, or maintenance in-progress.
  5. screen: Chamber X => Monitor Chamber
    Verify that Turbo indicator = ON.
  6. Are there any current system Errors or Faults? If needed, ask for maintenance assistance.
  7. screen: Program => Process Programs
    This will give you a list of the available recipes. Choose the desired recipes and verify parameters are correct, or change existing parameters.  A copy of the recipe should be in the chamber's book or, if you are using a non-standard recipe, you should have a copy of the etch parameters.  Please understand that anyone can change any parameter.  Any changes made are written to the recipe on the hard disk, so be sure to verify the recipe parameters, everytime you load the recipe. Do not expect the previous user to leave recipe parameters at default values.

    Paper copies of the programs are located in the logbooks at the p5000etch. They are organized according to the chamber used. The system has soft and hard ranges of parameters; soft ranges will give a message similar to ‘caution-may cause arcing’, but still accept the parameter change. Hard ranges will not allow the programming of that value, by giving an out of range message. Below is a list of parameters which may be changed or programmed:
    • Step Name: pops-up a alphanumeric keypad.
    • Chamber Choices: allows choice of chamber(s).
    • Endpoint: gives choice of endpoint by using endpoint detection, time, pressure in spec, pressure or time in RF.
    • Time: brings up the alphanumeric keypad.
    • No Endpoint/External Endpoint: if the endpoint detection system is to be used, the External Endpoint option must be chosen. To stop the etch by time, the No Endpoint option should be chosen. If left in External Endpoint, but the ‘by time’ option is chosen in Endpoint (above), you may watch the trace on the Endpoint PC without it affecting the etch time.
    • Gases and gas flows for each program step.
    • RF power for each step.
    • Chamber pressure for each step.
    • Gauss option for etch steps.

    Fill out a run sheet in the log book and note any change you have made from the default recipe parameters.  NOTE: if you change any parameters on standard recipes (those in the chamber A, B or C book) make sure that you change them back.  Due to an error message that the system is presently giving no new programs may be written.  Changing parameters back is extremely important.
  8. screen: System => Control
    Verify or set System State = "MANUAL".
    Set Cassette A to "RELEASE".
    Select "OPEN DOOR".
    Remove the blue Cassette from the A side of the load station. Note: removing the Cassette insures that the system software will recognize any changes made to the Sequence.

    Serial Sequence selection: __________ (to choose, click on underline sectionand verify at the input line)
    Verify Serial Sequence specifies correct sequence. Sequence defines which chamber(s) the wafer transport will take the wafer to, and in what sequence (as in first to Ch. C,  then to Ch. B)

    Chamber Process Program selection: __________
    Verify correct recipe(s) are specified for required chambers. Recipe defines what process will be performed in the etch chamber(s). NOTE: the system will not stop you from putting the program in the wrong input line, for ex. loading recipe CH.B OXIDE in the A input line.  You will get an error message after the wafer is loaded into the chamber.  Also, if you do not put a program in the input line (i.e., leave it as a blank selection) the system will put the chamber into Off Line for Maintence mode.  Here is a correct example for the etching process above:

    A (Blank Selection)
    B CH.B OXIDE
    C CH.C POLY
    D (Blank Selection)
    • Recipes steps can be ended in several ways:
    • by time
    • by operator command
    • by optical endpoint

    If optical endpoint is required, load the appropriate endpoint program into the Endpoint PC, and prepare it for triggering before wafers are loaded and the process recipe is started. Note: If recipe specifies Endpoint, but the Endpoint PC is not prepared to trigger, the recipe will Fault when the first wafer is placed in the etch chamber.
     

Select Endpoint Detection

The Endpoint PC Stand-by condition is with the monitor power switch turned off. The switch is located under the bottom right hand side of the monitor. The Endpoint PC CPU component is left powered ON.

 

To use endpoint detection:

  • Turn the monitor power switch ON. This will give you the trace of the last wafer which used endpoint.
  • Press ESC to get to the endpoint algorithm last used.
  • F10 will take you to the Main Menu page. 

  • NOTE: at this time the EP system is not responding to the F10 key.  To enter a new algorithm you will need to re-boot the computer by pushing CNT/ALT/DELETE.  The system will re-calibrate stepper motors A, B and C.  At the end of the calibration of stepper C the message 'Hit ESC for manual mode' will show.  Press ESC to get to the blue page.  Condinue as shown below.
  • Type in the desired algorithm, for example: su_al_lg.alg and hit RETURN to enter the algorithm.

  • F6 will load the algorithm.
  • F2 will put you into edit mode. Using the hard copy of the desired algorithm located in the logbook, check that the entered parameters are correct. If you need to enter new values be sure to use the enter key to make the changes. Beware! Do not assume the parameters are correct.
  • Press F2 to get into Process mode.  If alg has changed from what is in the file -you will be prompted.
  • The screen will show a message saying that the system is waiting for RF on to start the trace. This is correct.

 

Loading and Etching of Wafers

If these instructions do not allow the type of processing you feel is needed, ask for assistance

or clarification from appropriate staff. If screens or command fields are not described in this document – DO NOT use them.

  1. screen: System => Control
    Verify the System State is "MANUAL".
  2. Load wafers into cassette. Make sure that with the cassette loaded, all major flats are oriented towards the load lock. Failure to do this will not allow the wafer to seat on the chuck properly and result in damage to the chamber. Wafers start loading from the bottom (H-Bar side) of the cassette.
  3. Gently insert loaded cassette into the left hand cassette table (Table A) on the Load Station. Verify it is correctly positioned. It is subtle. Wafer must not be shaken out of position in the cassette slots.
  4. screen: Wafer => Monitor Wafer
    Select "Clamp A".
    Note: when cassette is clamped, the Sequence selection is highlighted in Green, and the Sequence can NOT be changed until Cassette is unclamped. Use the light pen to delete empty wafer positions on the cassette graphic on the lower left hand side of the screen. Choose the START DELETE RANGE at the first empty position and choose the FINISH DELETE RANGE at the last one. The graphic display will not show wafers if the cassette is not clamped.  NOTE: do not remove wafers on the display that are actually in the cassette.  You risk the handler crashing inot them and breaking the wafers.  Wafers that show up on the graphic display that are not really in the cassette are less of a problem; the system will try to put the wafer on the handler and will move on to the next one if it fails.
  5. screen: System => Control
    Select "System State: Automatic".
    Note: Wafer header will change color to GREEN while robot is homed, then BLUE when robot is ready to run.
  6. Press the front panel Run button to start processing the wafers. Intermittent audible Alarm will sound & outer plastic door will close
  7. screen: Wafer => Monitor Wafer
    Monitor the wafer transfer operation from this screen.
  8. When the first wafer is placed in the etch chamber, go to screen: Chamber X => Monitor Process
    Monitor recipe operation from this screen. You may now use the Previous Screen option at the lower right hand corner of the screen to toggle back and forth between the Wafer => Monitor Wafer and Chamber X => Monitor Process screens.
  9. Fill out the log sheets, particularly information about DC bias for the program steps and He cooling. You should have already filled out log sheets for any changes you have made to process or endpoint programs.
  10. When System header is blinking yellow, or when all process wafers have been returned to the A Cassette, the run is complete.

 

To stop loading any additional wafers into the etch chamber (the front panel STOP button): The Stop Button located on the front panel, will stop the wafer movement. A wafer being moved into an etch chamber at the moment the Stop button is pressed will continue into the chamber, and the process recipe will be run on the wafer – then the system will HALT and wait for operator action. If a process recipe is running, the wafer in the etch chamber continues to be processed but at the end of the recipe the wafer stays in the chamber – then the system will HALT and wait for operator action. Avoid using the Stop button while the robot is moving wafers – it is preferred to use Stop when a wafer etch is in-progress; this will prevent loading the next wafer into the chamber. Operator must give instructions to either retrieve wafer or continue processing. See Recover from Stop Procedure.

 

To stop recipe step before endpoint or pre-programed time is finished:

screen: Chamber X => Monitor Process => Chamber Commands

  • Stop Processing – stops the process in the displayed chamber. The time in the recipe and step halt.
  • Resume Processing – restarts the recipe after an interruption. The time in the recipe and step continue from the time when the recipe stopped processing. However, if RF power is on during the step, the system automatically stabilizes flow and pressure before resuming the process.
  • Restart Recipe Step - restarts the current recipe step at the beginning of the step.
  • End Current Step – ends the step being run, begins the next step, and continues processing. If this action is selected during the last step of a recipe, it is the same as selecting "End Current Recipe".
  • End Current Recipe - stops the current recipe and the wafer handler removes the wafer from the chamber.

 

Recover from Stop Procedure

If you get the error "Wafer did not drop on blade", DO NOT use this recovery procedure! Shutdown p5000etch on Coral. This procedure may be used to retrieve wafers that have been stopped during the processing. It must be performed in the following sequence:

After pressing Stop button on front panel:

  1. screen: Chamber Commands => End Current Recipe
  2. screen: System => Control
    Change "System State" to manual operation.
  3. screen: Wafer => Control Handler
    1. Abort load chamber operation.
    2. Abort current loader operation.
    3. Abort Automatic Sequencing.
    4. Home All Robot axes (wait about 2 min to complete).
    5. Return all wafers to cassette.

 

    If all wafers are not successfully returned to cassette, and system faults & halts, DO NOT attempt to continue using the machine. Contact Nancy Latta. Use Coral to report problem (or shutdown if required). Include details of how many wafers are in the machine and where they are located (e.g. in cassette, loadlock, on robot blade, in chamber, etc.), what sequence and recipe was running, etc. On logbook run sheet, record as much information as possible about your wafer type, deposited & grown films, resist, thickness, etc. Put a note on front of the machine to alert others of situation.

     

    Wafer Unload

    screen: System => Control System. Verify "System State: Automatic". Press front panel button "UNLOAD". Plastic door will open and Cassette will RELEASE. Unload cassette and reload with more wafers (orient flats toward loadlock) to continue etching, or go to Shutdown.

     

    Shutdown

    screen: System => Control System. Place empty cassette in A (left) side of Load Station. Select "System State: Manual". Select "Close Door". Turn Endpoint PC monitor power switch OFF. Disable p5000etch through Coral. Make sure logbook entries are completed. Logoff of p5000etch using light pen.

     

    Processing Information


    Etch Rates for Standard Programs

     

    Typical Etch Rates by Chamber

    The following information is provided to users of the Applied Materials Precision 5000 plasma etcher to aid in the use of the machine. This information is based on the programs Applied Materials originally provided.  Etch rates and selectivities should be considered guidelines and should be confirmed by the user by the use of test wafers.


    Chamber A METAL (CH.A METAL)

    Typical film stacks

    Al/Si on Tox, LTO, Ti or WTi, AlSi on LTO on Al/Si

    Sensitivity to process loading effects

    High

    Typical exposed film area

    40% to 60%

    Etch rates for usual films (Al/Si)

    ME >6000A/min
    OE >2000A/min

    Selectivity for usual films

    Al:PR >2:1
    Al:Tox >6:1

    Post etch treatment

    Manual DI rinse- this is remove any residual Cl that may be on surface of the wafer.  Cl may corrode metals.

    Endpoint specs (% exposed
    film and endpoint recipe)

    >40% su_al_lg.alg
    <40% su_al_sm.alg


    Chamber B OXIDE (CH.B OXIDE)

    Typical film stacks

    Tox on Si, LTO on Tox, LTO on AlSi,
    Si3N4 on Tox, Si3N4 on Si

    Sensitivity to process loading effects

    Low

    Typical exposed film area:

    -for Via and Contact
    -for Etchback and Spacer

     

    <5%
    ~100%

    Etch rates for usual films

    ME >3000A/min
    OE >3000A/min

    Selectivity for usual films

    Ox:PR >3:1
    Ox:Si >7.5:1

    Post etch treatment

    30 sec O2 plasma before wet chemical resist strip.  This is to rmove any polymer that has been deposited on the wafer.  It is due to the CHF3 chemisrty used in etching and must be removed before additional processing.  See Polymer Removal.

    Endpoint specs (% exposed film and endpoint recipe)

    At least 2% required for endpoint

    >20% su_ox_lg.alg
    <20% su_ox_sm.alg


    Chamber C SILICON and POLY (CH.C POLYETCH)

    Typical film stacks

    Poly on Tox, Si

    Sensitivity to process loading effects

    Low

    Typical exposed film area:

    -for Poly etch
    -for Trench etch

     

    40% to 60%
    <10%

    Etch rates for usual films

    ME >3000A/min
    OE >1500A/min

    Selectivity for usual films

    Poly:PR >3:1
    Poly:Tox >10:1 (ME)
    Poly:Tox >50:1 (OE)

    Post etch treatment

    10 sec 50:1 DI:HF dip

    Endpoint specs (% exposed film and endpoint recipe)

    -Poly with resist mask on Ox
    -Si etch including trench etch

     

    su_poly1.alg
    ?

     

    Endpoint Detection

     

    Theory of Operation

    The optical endpoint system uses the phenomenon of spectral emissions to sense endpoint. As the wafer is being etched, a reaction equilibrium of the plasma is sustained until a film being etched starts to clear. At this point, the increase of etchant species, such as CF2 in the case of an oxide film, and the decrease of reaction product species, such as CO (in the oxide case) cause the light intensities associated with the species to increase and decrease, respectively. By measuring the light emission intensity change associated with the chemical species in the plasma, an endpoint time can be determined and the end etch control signal will be sent to the P5000.

    Use of the spectral-emission phenomenon is dependent on the following conditions;

    • The signal level at the monitored wavelength must have sufficient intensity to be detectable.
    • The signal at the monitored wavelength must have a sufficient change in intensity level at the time of film transition.
    • The monitored wavelength must not have multiple substances associated with it that counter each other's signal levels.

     

    Recommended Wavelengths for Monitoring Endpoint

    Etch Application

    Film Type

    Species

    Wavelength

    Contact & Spacer

    Oxide over Si, poly, or silicide

    CO

    CF2

    483.5nm

    270 nm

    Via

    Oxide over metal

    CO

    CF2

    438.5nm

    270 nm

    Stack

    Oxide over nitride

    CO

    CN

    438.5nm

    386.5nm

    Isolation

    Nitride over oxide

    CN

    386.5nm

    Patterned Poly

    Poly over oxide

    Cl, Br

    Br

    470.5nm

    312.5nm

    Patterned Wsi2

    Wsi2 over poly or oxide

    F

    441.5nm

    Patterned TiSi2

    TiSi2 over poly or oxide

    Cl, Br

    470.5nm

    Patterned MoSi2

    MoSi2 over poly or oxide

    Cl, Br

    470.5nm

    Patterned Al

    Al-Si-Cu over barrier metal or oxide

    Al

    396 nm

     

    Process Gases and Maximum Flows by Chamber

     

    Chamber A- Metal

     

    Position
    Process Gas
    Maximum
    Flow
    7 CF4 100sccm
    8 Cl2 100sccm
    9 BCl3 100sccm
    10 N2 100sccm
    11 Ar 100 sccm
    12 SF6 500sccm

     

     

    Chamber B- Oxide

     

    Position
    Process Gas
    Maximum
     Flow
    1 He 20sccm
    2 CHF3 200sccm
    3 CF4 200sccm
    4 Ar 200sccm
    5 O2 100sccm
    6 N2 100sccm

     

     

    Chamber C- Silicon

     

    Position
    Process Gas
    Maximum
    Flow
    R11
    Cl2 100sccm
    R12 HBr 100sccm
    R13 NF3 200sccm
    R14 CF4 100sccm
    R15 SF6 100sccm
    R16 He/O2 20sccm

     

     

     

    Chamber C (poly Si) Clean Procedures

     

    The following chamber cleaning procedures were recommended by AMAT for various conditions.

     

    Clean to Minimize Grass

    The following pre-conditioning process is useful for minimizing grass from micromasking when doing Si trench etching in the P5000 using an oxide mask and the HBr/NF3/O2 process in Chamber C. 

     

    1. Run CH.C-CLEAN with bare Si wafer.
      Main: 90 NF3, 600mT, 350W, 55Gauss, 200 sec.
      Wafer should come out clear with no fog.
    2. Run 3 patterned seasoning wafers using trench etch process with 2 min main etch time. The oxide patterned wafers should have about the same pattern density as your real wafers. Although you may see some grass on the first wafer, the third should be mostly clean of grass in the etched areas. If grass is still a problem, the chamber most likely needs a wet clean. Note that this procedure was developed for wafers with 20 to 40% etched area.
    3. Etch wafers.

     

    Chamber Clean to be run before the Trench Etch Process

    It does not need to be run before each wafer.

     

    Program:

    Clean: 65 NF3, 15 He/O2, 50mT, 300w, 30Gauss, 200 sec

    Clean: 65 NF3, 15 He/O2, 350mT, 300w, 30Gauss, 300 sec

    Cool Down: 0 NF3, 15 He/O2, 150mT, 0w, 0 Gauss, 60 sec

     

    Pre-Clean Procedures Before Venting Chamber C

    Program 1) 10 to 515 sccm He/O2, 200-300 W, 100 mT, 74 Gauss, 10 min

    Program 2) 40 sccm CF4, 40 sccm O2, 500 W, 500 mT, 50 Gauss, 5 min

    Follow by 10 pump and vent cycles before venting.

     

    Post Wet Clean – Chamber C

    Pump chamber for minimum of 4 hrs.

    Run dry clean on 2 bare wafers for 20 min each 100 sccm SF6, 18 He/O2, 350 mT, 400W

    Season chamber with at least 15 wafers Seasoning of Chamber C below

    Season 15 wafers with either a) alternative bare Si and PR coated wafers or b) bare Si wafers.

    If idle for > 3 hrs, run 3 bare Si wafers.

    If new chamber, run 100 wafers to season.

     

    Seasoning of Chamber C  - to be done after chamber servicing

    Wafers: Cassette of 25 wafers alternating resist/bare

    Program:

    BreakThru: 35 CF4, 30 mT, 260 w, 10 s

    Main: 10 HBr, 30 Cl2, 100mT, 75 Gauss, 250 w, 60s

    Overetch: 30 HBr, 15 Cl2, 6 He/O2, 100 mT, 75Gauss, 90w, 60s

     

    Process Monitoring and Qualification Procedure

     

    Purpose

    To provide verification and trend of the standard programs including etch rates of AlSi, oxide, Si and photoresist, selectivity of those materials, and wafer-to-wafer and within-a-wafer uniformity of etch.

    Frequency of the Test

    To be completed after major maintenance such as cleaning or gas line replacement or on a set schedule to be determined or as needed based on user feedback.

    Documentation of Results

    To be posted in the equipment archive for p5000etch on the SNF website via coral and in a file or webpage available to users in data or chart format.

    Procedure


    Chamber A

    1. Wafers used for testing are one 1000A Al from a semi-clean metal deposition system on 1000A thermal silicon oxide, one 1000A silicon oxide wafer and one blank Si wafer, all 3 patterned with 1.6 3612 resist with SUMO Mask 2.0.

    2. Measure the resist and oxide thickness using a nanospec. Note results on the Process Qual Logsheet.

    3. Etch the metallized wafer using recipe CH.A METAL.  BT should be set to 6 secs, ME on endpoint and OE set to 0 secs.

    4. Set the main etch step to 1 minute (do not use endpoint) and etch the oxide wafer. Repeat for the patterned wafer.

    5. Note the time endpoint achieved and record on logsheet.

    6. Measure the resist thickness on the patterned wafer and record.

    7. Measure the oxide thickness on the oxide wafer and record.

    8. Strip the resist off the patterned wafer via matrix and read the single crystal etch depth using alphastep.  Record.

    9. Calculate selectivity for Al:resist and Al:oxide.

    10. Verify the results fall within the expected values listed on the wiki.

    Chamber B


    1. Wafers used for testing are 1000A patterned thermal silicon oxide and one bare Silicon wafer, and patterned stoichiometric Silicon Nitride wafer (700nm), all 3 with the SUMO mask 2.0 patterned with 1.6um 3612 resist.

    2. Measure the resist and oxide thickness using nanospec. Note results on the Process Qual Logsheet.

    3. Etch the oxide wafer using recipe CH.B OXIDE. Set the main etch time to 1 minute.  Over etch should be set to 0 secs.

    4. Etch the bare Si wafer using recipe CH.B OXIDE. Set the main etch time to 1 minute.  Over etch should be set to 0 secs.

    5. Measure the resist thickness and record.

    6. Measure the oxide thickness and record.

    7. Strip resist and measure the Si etch depth using alphastep.

    8. Calculate the etch rate of the oxide.

    9. Calculate selectivity for oxide:resist.

    10. Calculate the selectivity for oxide : Si.

    11. Verify the results fall within the expected values.


    Chamber C

    1. Wafers used for testing are 700nm polysilicon on 1000A thermal silicon oxide wafer, one 1000A oxide wafer and one Si wafer, all 3 with the SUMO mask 2.0 patterned in 1.6um 3612 photoresist.

    2. Measure the resist and oxide thickness using nanospec. Note results.

    3. Etch the wafer using recipe CH.C POLY.  Set the break through step to 6 secs, main etch time to 1 minutes and over etch to 0 secs.

    4. Measure PR thickness on SiO2 wafer and Si wafer.

    5. Strip the resist off of all 3 wafers.

    6. Measure the oxide etch depth via alphastep and record.

    7. Measure Si etch depth via alphastep and record.

    8. Measure the PolySi etch depth via alphastep and record.

    9. Calculate the etch rate of the oxide and record.

    10. Calculate the etch rate of the resist and record.

    11. Calculate the etch rate of poly and record.

    12. Calculate selectivity for poly:resist (average resist between wafers).

    13. Calculate selectivity for oxide:resist.

    14. Verify the results fall within the expected values.

     

    Recent results

     

    For recent process qualification results click here.

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