23  Aug. 15,2002  US 2002/0111024 Al  with no abrasive, but just a  POLITEX  pad, the polishing rate  is below 100 Angstroms per minute.  [0278]  Ammonium Bifluoride  [0279]  NH$_{4}$HF$_{2 }$ [0280]  NH$_{4}$HF$_{2}$ ,  an excellent fluoridizer, gave only 40 to  90 Angstroms per minute polishing rates when used at  pH  2-5, concentrations of 1 % to 5%, with or without abrasives.  Addition of a small amount of hydrogen peroxide and of  surfactants, less than 1  %  of each, improved the polishing  rate a small amount.  [0281]  Others  [0282]  Secondary oxidizers such as ammonium lactate at  5% and at  pH  4-8, 20% periodic acid at  pH  12, Gluconic acid  at 20% and at  pH  2.1, ammonium phosphate at 5% and at  pH  4-7, and ammonium hydroxide at 10% and at  pH  12.6,  showed poor polishing rates.  [0283]  Oxide Substrate  [0284]  Hydroxylamine, an excellent oxidizer for copper  and other substrates, can also be used in a reductive capacity  to polish metal oxides. The formulation is beneficially at  least 9, preferably between 9 and 12, more preferably  between 10 and 11. A formulation of 10% hydroxylamine  was prepared and adjusted to pH 10.6. This formulation was  added at 50 ml per minute to an 8% slurry of MOY SC  abrasive, and the formulation was applied to a 3" BPSG  substrate with a IC 1000 pad at 33 rpm and 2 psi pressure.  The polishing rate was greater than 380 Angstroms per  minute. The formulation was allowed to age 21 days.  It was  found to have a pH of 10.7, and the polishing rate was above  340 Angstroms per minute.  [0285]  A formulation of 10% hydroxylamine was pre› pared and adjusted to pH 10.6. This formulation was added  at 50 ml per minute to an 8% slurry of MOY SC abrasive,  and the formulation was applied to a 3" BPSG substrate with  a POLITEX pad at 33 rpm and 2 psi pressure. The polishing  rate was 558 Angstroms per minute.  [0286]  Hydroxylamine  nitrate  at  0.5%  with  0.02%  Hydroxylamine at  pH  4 was found to have a polishing rate  of only 37 Angstroms per minute when added at 50 ml per  minute to an 2.5% slurry of  MOY SC  abrasive and the  formulation applied to a 3"  BPSG  substrate with a IC 1000  pad at 33 rpm and 2 psi pressure.  [0287]  Periodic acid at 3% and pH 6.5 was found to have  a polishing rate of only 9 Angstroms per minute when added  to a 2.5% slurry of MOY SC abrasive and the formulation  applied to a 3" BPSG substrate with a IC 1000 pad at 33 rpm  and 2 psi pressure.  [0288]  High polishing rates, for example greater than 400  Angstroms per minute, were observer with potassium  hydroxide and with ammonium biflouride in water.  [0289]  Ammonium Persulfate  [0290]  A  variety of Ammonium persulfate formulations  were tested on aluminum wafers.  [0291]  Tests were run with Ammonium persulfate com› positions of 2%, added at 50 ml per minute, using a  MoycoMC™ 1  %  formulation at 33 RPM at 2 psi force with  a IClO00™ pad on a 3 inch IWS wafer. The polishing rate  at pH 4 was 425 Nminute, while at pH 2 the rate was only  365 Nminute.  [0292]  The Ammonium persulfate composition is prefer› ably between about about 0.5 to 10%, preferably between  0.5 to 6%, more preferably between about 1 to 4%, and most  preferably about 2%. The MoycoMC™ formulation is pref› erably between about 0.1 to 4%, and more preferably about  1%.  [0293]  Testing was also performed on 3"  IWS  aluminum  wafers with Politex™ pads at about 2 psi at 33  RPM.  In a  first formulation, the slurry included 20 ml/minute of 5%  Moyco™ abrasive in 90 ml/minute 5% Ammonium persul› fate. The pH was held at 5.9. The polishing rate was a very  low 1 Nminute. This result was confirmed in a duplicate  test.  [0294]  In a second formulation, the slurry included 20  ml/minute of 5% alumina abrasive in 20 ml/minute 5%  Ammonium persulfate. The pH was held at 4.5. The pol› ishing rate on a 3" EMF substrate was a very high 4280  Nminute.  [0295]  According to the first formulation, the Ammonium  persulfate is delivered at a flow rate of between about 50 to  150 ml/min., more preferably between about 80 to 120  ml/min., and most preferably about 90 ml/min. According to  the second formulation, the Ammonium persulfate is deliv› ered at a flow rate of between about 5 to 50 ml/min., more  preferably between about 10 to 40 ml/min., and most  preferably about 20 ml/min. The MoycoMC™ abrasive  formulation is preferably between about 0.5 to 10 wt. %,  more preferably between about 2 to 8 wt.  %, and most  preferably about 5 wt. %, and is delivered at a flow rate of  between about 5 to 50 ml/min., more preferably between  about 10 to 40 ml/min., and most preferably about 20  ml/min. The alumina formulation is preferably between  about 0.5 to 10%, more preferably between about 2 to 8%,  and most preferably about 5%, and is delivered at a flow rate  of between about 5 to 50 ml/min., more preferably between  about 10 to 40 ml/min., and most preferably about 20  ml/min.  [0296]  A  5% Ammonium persulfate solution at  pH  of 3.4  that was added at 20 ml/minute gave an aluminum polishing  rate of 105 Nminute on a 3 inch  IWS  wafer, polished with  a Polytex™ pad at 33  RPM  at 2 psi. A 10% Ammonium  persulfate solution, with all other parameters remaining the  same, gave a polishing rate of 23 Nminute on a 3 inch  EMF  wafer  [0297]  Certain organic acids can enhance/retard polishing  rates. In addition to citric acid, oxalic acid and gluconic acid  were tested here. Oxalic acid added at 1 % to a 10%  Ammonium persulfate solution at 20 ml and at  pH  1.4 using  a Polytex™ pad on a 3 inch  IWS  wafer at 33  RPM  and 2 psi,  gave a polishing rate of 23 Nminute. Gluconic acid added  at 20% to a 10% Ammonium persulfate solution at 20 ml and  at  pH  1.4 using a Polytex™ pad on a 3 inch  IWS  wafer at  33  RPM  and 2 psi, gave a polishing rate of only 6.8  Nminute.  [0298]  The Ammonium persulfate concentration is pref› erably between about 2 to 20%, more preferably between  Example 6  Aluminum Substrate  Example 5 