Chapter 7.6

Centura® MxP+ Chamber

(centura-mxp)

 

1.0         Title

Centura Platform System MxP+ Chamber Operation Manual

2.0         Purpose

The Centura MxP+ is a magnetically enhanced reactive ion etch chamber typically used for etching oxide and nitride patterns in the wafer.

3.0         Scope

The Centura platform is a fully automated, multi-wafer capacity, multi-chamber system. The system consists of a mainframe assembly (loadlocks, transfer chamber, process chambers) and an associated set of remote support equipment (RF power supplies, vacuum pumps, heat exchangers, computers). All wafer handling and processing takes place in the mainframe assembly. Operator interface takes place at the Centura computer terminal located at the front of the system.

The etch process in the MxP+ chamber is enhanced by applying a rotating magnetic field to the plasma, which increases the residence time of free electrons in the plasma. This causes more collisions between the free electrons and the gas molecules, resulting in a more ionized and reactive gas. Four symmetric electromagnetic coils are located around the perimeter of the etch chamber. Current flow through the coils produces a rotating magnetic field. The strength of the magnetic field is 0 gauss–100 gauss. The magnetic field lowers the DC bias voltage potential between the chamber anode (gas distribution plate and the chamber walls), and the chamber cathode by lowering the resistance of the plasma. The coils are only turned on during processing.

The simple cathode is the RF driven electrode inside the etch process chamber. The cathode receives up to 1200 W (depending on the process) of 13.56 MHz RF power from the RF generator in the remote frame. A high voltage polyimide electrostatic chuck secures the substrate within the process chamber during the process. The ESC pedestal has helium channels cut into its face. The channels distribute helium across the back of the wafer. This helium flow increases the heat transfer from the wafer to the pedestal to prevent photoresist reticulation on the wafer.

4.0         Applicable Documents

Revision History

4.1         MxP+ Dielectric Etch Centura Chamber Manual (Applied Materials® document)

4.2         Silicon Etch Centura Mainframe (Applied Materials® document)

4.3         Material Safety Data Sheets for the following gases: CH3F, O2, CHF3, C4F8, CF4, Ar, He, and N2 (copy in Microlab lobby).

5.0         Definitions, Process Terminology, Equipment Configuration

Acronyms and other terminology used in this document

5.1         AR: Aspect Ratio (the height to width ratio of a feature)

5.2         Ch A: Chamber A; designation of DPS DT silicon etch process chamber

5.3         Ch B: Chamber B; designation of MxP oxide etch process chamber

5.4         Ch E: Chamber E; designation of the cool down chamber. Note: Ch E not used with current Centura configuration.

5.5         Ch F: Chamber F; designation of flat finder or orienter chamber.

5.6         CRT: Cathode Ray Tube

5.7         DPS DT: Decoupled Plasma Source Deep Trench platform. Note: DPS DT has a separate operations manual, and a separate qualification is required to use this chamber.

5.8         DRIE: Deep Reactive Ion Etch

5.9         DTCU: Dome Temperature Control Unit

5.10      ESC: Electrostatic Chuck

5.11      LLA: Loadlock A

5.12      LLB: Loadlock B

5.13      MFC Mass Flow Controller

5.14      MxP: Oxide etch chamber

5.15      RF: Radio Frequency

5.16      SOI: Silicon On Insulator

5.17      TGV: Throttled Gate Valve

5.18      TMGM: Time Multiplexed Gas Modulation

Equipment Configuration:

All processes occur in the process chambers. There are two process chambers currently configured to the Centura platform: Ch A (DPS DT), and Ch B (MxP). The following describes other important components currently configured to the Centura platform.

5.19      Dual Loadlock Chambers

The Centura has two aluminum loadlock chambers. They are referred to as loadlock A (LLA) and loadlock B (LLB). Under normal operating conditions, wafers that are to be processed in Ch A (DPS DT) should be loaded using LLA. Likewise, under normal operating conditions, LLB should be used for loading wafers into Ch B (MxP). The loadlock chambers serve the purpose of isolating the transfer chamber from atmosphere during wafer cassette loading or unloading. Each loadlock has an automatic platform that raises and lowers the wafer cassette in order to move substrates to or from the transfer chamber. Each loadlock holds one blue 6-inch wafer cassette with a 25-wafer capacity.

5.20      Flat Finder Chamber (Ch F)

The wafer orienter chamber; also known as the flat finder chamber or Ch F. This chamber is used to locate the major flat of the wafer so that it can be positioned in the process chamber properly via the wafer handler robot arm. Wafers to be processed always go through Ch F before being placed in any process chamber.

5.21      Transfer Chamber

The transfer chamber isolates the process chambers from the loadlocks during wafer transfer functions. It is also known as the buffer chamber, and essentially “deals” wafers to the processing or flat finder chamber with the wafer handler robot arm. The transfer chamber is held under vacuum and provides a clean neutral environment for wafer transfer to take place.

5.22      Cool Down Chamber (Ch E)

Cooldown chamber. Neither the DPS nor MxP chambers need to make use of Ch E. Thus, this chamber is not used with the current configuration, and is set to an “offline” state by default. (Note: The cool down chamber is primarily used in conjunction with chambers that run relatively high temperature processes such as LPCVD).

5.23      Heat Exchangers

Three separate HX 150 Neslab heat exchangers are used for various cooling applications within the Centura platform. All of the heat exchangers provide closed loop temperature control. Chilled DI water is used as the coolant.

5.24      Gas Cabinet

The gas cabinet is located on the top rear of the centura mainframe. The gas cabinet consists of the following components: MFCs, transducers, tubing valves, regulators, filters, gas detectors, and safety interlock switches. Process gas control and distribution to the process chambers takes place via the gas cabinet. The gases configured for use with the MxP+ are: CHF3, N2, CF4, Ar, C4F8, O2, CH3F.

Software Overview

System operations are accessible through the CRT monitor screen by touching the lightpen to a field on the screen and pressing the lightpen button. This activates the field. There is a hierarchy to the screens and “detail” screens are reached through pulldown menus from the header line. There are 8 main header line fields with the present Centura software/hardware configuration (described below). A schematic of these headers and the pulldown menu hierarchy are shown in Figure 2. Some of the more User-relevant pulldown menu options that can be accessed by selecting these headers are listed as follows:

 

5.25      System header - The more often used options in this pulldown menu include the Login \ Logout option, the Control System screen option, and the Enter Lot Names For screen option.

5.26      Wafer header - Among several other options, this pulldown menu consists of the Monitor Wafers screen, the Monitor Handler screen, and the Load \Unload A option.

5.27      Ch A  header - This pulldown menu includes Monitor Process, Monitor Chamber, and Monitor Gas Panel screen options for the DPS DT process chamber.

5.28      Ch B header - This pulldown menu consists of the Monitor Process, Monitor Chamber, and Monitor Gas Panel screen options for the MxP process chamber.

Note: Ch A has a separate operations manual, and a separate qualification is required to use this chamber.

5.29      Ch E header - This pulldown menu not used with current configuration. Ch E is offline.

5.30      Ch F header - This pulldown menu includes the same options as listed for the Ch A pulldown menu.

5.31      Program header - The important User-relevant options in this pulldown menu include the Wafer Sequencing, Process Programs, and Lot\Sequence Control screen options.

5.32      Misc header - The most User-relevant option in this pulldown menu is the Vacuum Service Screen.

6.0         Safety

The Etch MxP+ Centura system uses reactive gases that require careful handling. These gases are toxic, poisonous, flammable, or caustic. The system also uses high voltage electrical power, radio frequency (RF) energy, microwave energy, and magnetic fields.

6.1         RF Power

This system, like many other dry etching systems, uses high-power radio-frequency (RF) energy to generate plasma. Avoid touching or otherwise disturbing RF cables at all times.

6.2         UV Radiation

Ultraviolet light is generated in the etch chamber during normal operation. View port allows the plasma and wafer to be observed. An ultraviolet shield provides eye protection. The view port is recessed to allow endpoint detection.

 

6.3         Automatic Loadlock (LLA, LLB)

Users must be aware of moving loadlock doors and components at all times. !!! Moving parts can crush or cut !!! Be aware that the cassette handler in the loadlock swings out and down automatically. Keep away from loadlock doors during automatic loading or unloading. Keep away chairs or other items that would potentially interfere with the loadlock doors or cassette handler at all times.

6.4         Emergency Stop Button

Red button located on front panel of tool. Pressing this button will cut power to the entire system. Use this button only if person or equipment is in harm’s way - e.g. earthquake, flood, or for any other dire circumstance.

7.0         Statistical/Process Data

(under construction…)

8.0         Available Processes, Process Notes

8.1         The Centura MxP+ is a six-inch compatible wafer system. Please contact process staff regarding the potential processing of a different size substrate at this time. 

8.2         Standard Recipes: All of the standard recipes on MXP are password protected. They are permanent, and may not be modified. Contact staff with requests for new, permanent recipes specialized for your application.  Ideas for new recipes and suggested improvements to current recipes are encouraged.

8.3         Variable Recipes: The recipe entitled MXP VARIABLE is a User-modifiable recipe. For the time being, all parameters in this recipe are open to modification by Users. Please contact staff about questions that may arise concerning editing process parameters. Note that there are no default parameters for the recipe MXP VARIABLE. WYSIWYG!

Table 1 - MxP+ Chamber Available Standard Recipes

Recipes à

MXP-OXIDE-ETCH

MXP-OXSP-ETCH

MXP-NITRIDE-ETCH

MXP-NITRIDE-ETCH

MXP-NITSP-ETCH

MXP-BARC-ETCH

Recipe Purpose

Standard Oxide Etch

Oxide Spacer Etch

Standard Nitride Etch Main Etch Step

Standard Nitride Etch Overetch Step

Nitride Spacer Etch

Anti Reflective Coating Etch

Power (W)

700

500

500

450

300

250

Pressure (mT)

200

200

50

50

50

100

Ar flow

150

120

110

50

90

-

CF4 flow

15

10

20

-

45

75

CHF3 Flow

45

50

15

-

10

-

CH3F Flow

-

-

-

50

-

-

C4F8 Flow

-

-

-