STANDARD METAL CLEAN INFORMATION

WHO NEEDS IT?

1. Wafers that have metal on them should get this clean. What metal is on your wafers (or was on and was removed) will determine where the clean should be done (see section below "Where should I do it?" for details) and what equipment your wafers will be allowed in (See MATERIALS ALLOWED for details).
2. Standard Metal Clean should be done on wafers that are going into a furnace (i.e. tylanfga), LPCVD system (i.e. tylanbpsg metal side only) or metal deposition (if the wafers already have metal on them). Note: The equipment used in this example only allow "standard metals" (standard metals are Al, Ti and W), refer to MATERIALS ALLOWED to find what equipment you can use with wafers exposed to nonstandard metals.
3. Wafers should be loaded into the furnace or deposition within one hour of the clean process. If they sit longer than one hour they MUST be RECLEANED.
4. Wafers with resist on them should get Resist Strip Metal (SVC-127) before going into the Standard Metal Clean (PRS1000).
5. IMPORTANT NOTE: Never touch your wafers. If you do they must be thrown away because there is no clean that can remove the contaminants left by fingerprints.
   

WHAT IS THE PROCESS

• PRS1000 @40C for 5 minutes
• Dump Rinse (std 6 cycles) OR overflow rinse for 5 minutes (if at wbgeneral)
• Spin Dry (280 seconds rinse; 120 seconds spin dry; Auto Mode; >16 ohm-cm Rs on DI H₂O) OR if you are using wafers that do not fit into a spin dryer or a wetbench that does not have one blow dry the wafers on clean room lint free papers using a N₂ gun.
• Dump Rinse (std 6 cycles) OR overflow rinse for 5 minutes (if at wbgeneral)
• Spin Dry (280 seconds rinse; 120 seconds spin dry; Auto Mode; >16 ohm-cm Rs on DI H2O) OR if you are using wafers that do not fit into a spin dryer or a wetbench that does not have one blow dry the wafers on clean room lint free papers using a N₂ gun.

NOTE: The double rinse is and spin dry is to remove any residue that may be left by the PRS1000.

VARIATIONS?

1. If you are going to metal deposition or an LPCVD deposition you may need to do an HF dip and DI rinse after your clean . This prevents an oxide from being between the silicon and the metal deposition

HOW DOES IT WORK?

1. The PRS1000 solution removes the organic contaminants from the wafers.
2. When an HF dip is done last it removes the chemical oxide put on by the previous clean step.

WHERE SHOULD I DO IT?

1. The process is used to clean wafers that have metal on them.
2. STANDARD METALS: If the wafers have standard metal (Al and W are "standard metals") on them (or had standard metal on them and it was removed) and they have never had any non-standard metals or GaAs on them (or been in equipment contaminated with nonstandard metals or GaAs) they may be cleaned at wbmetal(4",3",2" wafers) OR at wbgeneral in designated standard metal quartz beakers (nonstandard sized wafers or pieces of wafers). Wafers cleaned this way could go into standard metal furnaces (i.e. tylanbpsg (metal side ONLY) and tylanfga).
3. NOTE: There is a cassette available for cleaning 6 " wafers
4. NON-STANDARD METALS: Wafers that have had non-standard metals on them or have been in equipment contaminated with non-standard metals must be cleaned at the wbgeneral in your own clearly labeled designated non-standard metal ONLY quartz beakers and can only go into equipment that allows those materials (see Materials Allowed for details). NOTE: the gold designated Pyrex beakers  may be used if the equipment you need to use allows gold and other non-standard metals (do not do an HF dip in Pyrex beakers though because you will get contaminants from the beakers on your wafers -- sodium, boron, etc....).