# Patent

## Title
CMP formulations

## Abstract

CMP formulations for use on nickel/phosphorus alloys comprising abrasive particles and an oxidant, a modifier for the action of the oxidant and first and second accelerants to sequester removed materials containing phosphonate and ammonium or amine groups respectively and optionally an organic carboxylic acid.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a of U.S. patent application Ser. No. 10/080,853, filed Feb. 22, 2002 now U.S. Pat. No. 6,755,721, entitled “Improved Mechanical Polishing of Nickel Phosphorous Alloys,” naming inventors Douglas Edwin Ward and David Solomos, which application is incorporated by reference herein in its entirety.


TECHNICAL FIELD OF THE INVENTION
This invention relates to CMP (“chemical mechanical planarization”) materials and specifically to CMP materials for use in treating nickel-phosphorous alloys. The specific alloys targeted by the present invention are known as high-phosphorus alloys and contain 9 to 12 wt % of phosphorus, such alloys are conventionally deposited via an auto catalytic nickel plating process, typically called electroless nickel plating. Specifically in the manufacture of hard disks for hard-disk-drives (memory storage media), said nickel-phosphorous alloys are deposited on an aluminum substrate.
BACKGROUND OF THE INVENTION
To manufacture hard disk drives, certain processes require an electroless nickel-plated substrate to demonstrate a highly planar surface. “Planarity” is quantified through the measurement of “waviness”, “flatness” and “roughness”. In addition to planarity, certain criteria determine the further processing of post electroless nickel-plated, aluminum substrates. In totality, these criteria are “waviness”, “roughness”, “outer diameter curvature”, “flatness” and surface defects. Waviness, roughness, outer diameter curvature and flatness are to be at a minimum in this context. Surface defects such as “pits”, “bumps” and “scratches” are defined by any disruption in the nickel-phosphorus lattice, which has a depth or height greater than or equal to twelve angstroms. In addition to seeking a planar surface that is void of surface defects, the CMP process of nickel-phosphorous plated, aluminum substrates must be accomplished in an efficient manner with respect to cycle time and labor intensity.
Currently available CMP formulations have not succeeded in removing a Ni—P layer at an adequate rate when using abrasive particles consistent with achieving an adequately planar surface. In practical terms this means abrasive particle sizes of from 15 to 120 nanometers. As a result the tendency has been to use abrasives with a larger particle size to reduce the mean distance from “peaks” to “valleys” across the nickel-phosphorous surface very rapidly and follow with a process using particles with a range from 15-120 nm to create a “fine” finish with respect to planarity and surface defects. A “fine” finish is defined by the optimum surface condition available to this specific process.
The CMP formulation of this invention is specifically designed to create a surface on a nickel-phosphorous layer that is suitable in all respects for further operations in the fabrication of a superior electronic component. Specifically it is capable of producing a highly uniform, minimum waviness surface in a one-step operation. It does this by using a CMP formulation that greatly increases the material-removal effectiveness of abrasives with particle sizes more usually associated with the later polishing operation.
Normally in this context the CMP surface-generating process is accomplished in two operations: a first involving aggressive material removal until an approximate level is achieved and thereafter a more gentle process in which the desired surface finish, in terms of low surface roughness and micro-waviness, is pursued. The solutions used in the first polishing stage are frequently comprised of abrasive particles, (usually of alumina), with a particle size of from about 0.3 to 0.44 micrometers, and a chemical accelerant. The second action is a planarization action in which the surface defects created by the first material removal action are removed and a surface with an acceptable pre-determined smoothness and minimal waviness is created. This second stage of polishing is typically accomplished, using a finer abrasive (colloidal silica) and a chemical accelerant, in the presence of an oxidizer.
The two sequential operations can take a substantial amount of time and are labor intensive. As a two-step process also requires more handling of the substrates surface defects are commonly introduced by human handling and transport of the product. It is therefore desired to fabricate a process where a substrate is properly processed via CMP in one step and on a single piece of equipment. A suitable formulation meeting these criteria has now been devised which can be used on a nickel/phosphorus alloy surface to create a finish equivalent to that obtained using a conventional two-stage process, in the same as or reduced time frame.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a statistical analysis diagram of removal rate data.
FIG. 2 is a statistical analysis diagram of surface roughness data.



GENERAL DESCRIPTION OF THE INVENTION
The present invention provides a CMP formulation for the treatment of a nickel/phosphorus alloy which comprises a dispersion of abrasive particles with particle sizes from 15 to 80 nanometers and selected from the group consisting of silica, alumina, titania, ceria, zirconia and mixtures thereof dispersed in a formulation having a pH of from 2.4 to 2.6 comprising:

    
    
        a. an oxidizer;
        b. a chemical accelerant comprised of four groups:
        
            (1) a phosphonate
            (2) a carboxylic acid
            (3) a phosphate or phosphite
            (4) an amine
        
        
        c. water.
    
    


The invention further comprises a single-step process comprising subjecting a nickel-phosphorus alloy containing from 9 to 12% phosphorus deposited on a substrate to a CMP process using a formulation as described above.
In preferred formulations according to the invention the formulation comprises an organic carboxylic acid. This compound attacks the surface and makes removal of the alloy more easily accomplished. Examples of suitable acids include citric acid, oxalic acid, lactic acid, tartaric acid, glycine and mixtures of such acids.
The formulations of the invention are carefully balanced to provide that the attack of the oxidant, (and any organic carboxylic acid present), on the nickel-phosphorus alloy surface is not so vigorous that material is removed in uncontrollable amounts that can not be adequately sequestered by the phosphonate group in the accelerant which is a chelating agent effective to chelate nickel removed from the surface of the nickel-phosphorus alloy and prevent re-deposition, or increase solubility by reacting with ligand providing components in the formulation. An important element of the balance is to maintain the pH at the above level and the level of the second accelerant plays an important role in this regard.
In selecting the oxidant, the most preferred example is hydrogen peroxide because of the purity of the product and because it leaves little or no residue. However other know oxidants, such as periodates, sulphurous acid and percarbamates, can be used in partial or complete substitution for hydrogen peroxide unless there is a compatibility problem as is the case for mixtures of hydrogen peroxide and potassium periodate. The preferred oxidant is however hydrogen peroxide and most preferably in the form of a 35% by weight solution in water.
The moderator for the activity of the oxidant comprises a phosphite or phosphate group having the group —POx, where x is from 1 to 4. The preferred exemplar is phosphoric acid, (including the meta-, ortho-, and pyrophosphoric acid versions).
The accelerant also comprises chelating phosphonate groups and suitable examples include 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), aminotri (methylenephosphonic acid) (ATMP), N-(2-hydroxyethyl)-N,N-di (methylenephosphonic acid) (HEMPA) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC).
Of these HEDP is preferred. This component increases the solubility of the nickel removed from the surface and aids in producing a clean surface readily flushed clean of all CMP residues.
The accelerant also comprises amine, amide or ammonium groups and suitable exemplars of such compounds include ammonium hydroxide, ammonium salts such ammonium nitrate, urea, formamide acetate, biuret, ethylene diamine and glycine. Mixtures of such compounds can also be used. This compound also acts as a ligand to keep nickel in a soluble form after removal from the surface.
The amounts of the components in the formulation are preferably as follows:

    Abrasive: from 2 to 10 and more preferably from 3 to 6 wt. %;
    Oxidizer: from 1 to 6 wt. % and preferably 1 to 4 wt % of the active oxidant.
    Phosphate or Phosphite: from 0.1 to 6 and more preferably from 0.1 to 4 wt. %;
    Phosphonate: from 0.1 to 6 and more preferably from 0.1 to 4 wt. %;
    Amine, Amid, Amide or Ammonium: from 0.1 to 6 and more preferably from 0.1 to 4 wt. %; and
    Organic Carboxylic Acid: from 0.1 to 6 and more preferably from 0.1 to 4 wt. %.
    Water: The balance up to 100 wt. %


The most preferred abrasive component of the mixture for use on nickel-phosphorus substrates is silica, having a mean particle size of 15 to 120 nm, preferably from 15 to 80 nm and most preferably from 15 to 60 nanometers. The most suitable silicas have mono-dispersed, essentially spherical particles. Two suitable silica solutions are available as 30% by weight solid dispersions. A-Green Corp. and DuPont AirProducts NanoMaterials manufacture these products under the trade names BESIL-38A and Syton HD-700 respectively. Of these solutions, Syton HD-700 is preferred.
DESCRIPTION OF PREFERRED EMBODIMENTS
EXAMPLES
A statistically analytical approach was utilized to formulate this invention. In order to eliminate excess variables in the development process, certain equipment and parameters were held constant. These equipment and their parameters were as follows:










TABLE A









Polish Machine
Speedfan 9h-5



Lower Platen Speed
  4.0 rpm



Sun Gear Radius
  3.5 Inches



Sun Gear Speed
  9.5 rpm



Ring Gear Speed
  8.5 rpm



Carrier Diameter
  9 inches



Number of Work Pieces
  6



Total Down Force
 48 kg



Process Time
  6 minutes



Ramp to Down Force
 20 seconds



Total Slurry Flow-Rate
 126 mL/min



Polish Pad
Rodel - DPM 1000



Roughness Measurement
Schmitt TMS



Removal Measurement
Satorius 3100S Balance



Cleaning Machine
Oliver Singe Rail



Double-Spaced



Number of Work Pieces
 10



Brush Pressure (air)
 40 psi



Soap Time
  1 sec



Rinse Time (D1 spray)
  1 sec



Detergent
AmberClean 527-L



Drying Machine
Semitool Stand-Alone Dryer



Rotor Speed
2700 rpm



Rinse Cycle
 30 sec



DI Flow Rate
  .5 gpm



Dry Cycle
 180 sec



Air Pressure
 60 psi










The procedure by which slurry was evaluated through this development process is depicted in the flow chart below:







TABLE B





Silica Slurry Evaluation Process Flow Diagram





















In addition to holding the procedures and process equipment and parameters constant, the concentration of colloidal silica was held constant at 5.71 percent by weight. This is to say that in every iteration of slurry, the concentration of colloidal silica by weight was held constant at 5.71 percent.
Example 1
This example illustrates the contribution to removal rate by individual chemical groups in the presence of an oxidizer. An initial screening was to be performed involving forty-eight different constituents. At this initial stage of testing, the concentration of hydrogen peroxide as a thirty-five percent by weight solution was held constant at 2.57. This is to say that during the first phase of the slurry development process hydrogen peroxide in the form of a thirty-five percent by weight solution was held constant in every iteration of slurry at a total percentage by weight of 2.57. Each of the remaining forty-seven constituents was evaluated as a one percent by weight solution comprised of silica as described above, hydrogen peroxide as described above, the specific constituent and the remaining weight percent water. A listing of these constituents and the product codes assigned to them are found in table 1a. The procedure by which each of these constituents was evaluated is according to the Process Flow Diagram depicted in table B. Removal rate data in the form of total grams removal was collected from each slurry evaluated. This data was then analyzed by analysis of variance and a p-value obtained. A p-value of 0.00 was observed indicating that there was greater difference in removal data from slurry to slurry than within the data set acquired for an individual slurry. This is to say that there is sufficient statistical data to make inferences about the performance of each slurry. The data concerning the total removal of the nickel-phosphorous layer facilitated by each slurry is displayed in table 1b.










TABLE 1a





Date Run
Code Name
Accelerants
Comments







Mar. 07, 2001
A0
Hydrogen peroxide, 35%




A1
Ammonium nitrate



A2
Hydroxylamine nitrate, 50%



A3
Monoethanolamine


Mar. 09, 2001
A4
Guanidine carbonate



A5
Ethylenediamine



A6
Aluminum nitrate, 9hydrate



A7
Calcium nitrate, 4hydrate



A8
Ceric ammonium nitrate


Mar. 12, 2001
A9
Chrome III nitrate, 9hydrate



A10
Copper II nitrate, 3hydrate



A11
Magnesium nitrate, 6hydrate



A12
Nickel nitrate, 6hydrate


Mar. 14, 2001
A13
Potassium nitrate



A14
Potassium stannate, 3hydrate
Incompatibility with hydrogen





peroxide, not evaluated



A15
Zinc II nitrate, 6hydrate



A16
Cyanic acid
Possible safety issues existed, not





evaluated


Mar. 16, 2001
A17
HEDP, 60% aqueous



A18
Ammonium fluoroborate



A19
Sodium fluorophosphate



A20
HPA, 50% aqueous



A21
Potassium iodate


Mar. 19, 2001
A22
Potassium periodate
Incompatibility with hydrogen





peroxide, not evaluated



A23
Phosphoric acid, 85%




aqueous



A24
Sodium selenate



A25
Ammonium thiocyanate



A26
Ammonium vanadate
Possible safety issues existed, not





evaluated


Mar. 20, 2001
A27
Citric acid



A28
L-Cysteine



A29
Glycine



A30
Lactic acid



A31
Oxalic acid


Mar. 21, 2001
A32
Tartaric acid



A33
Hydrogen peroxide, 35%



A34
Urea



A35
Oxamide
Possible safety issues existed, not





evaluated



A36
Cyanamide
Possible safety issues existed, not





evaluated


Mar. 22, 2001
A37
Dimethylglyoxime
Incompatibility with hydrogen





peroxide, not evaluated



A38
Manganese II nitrate, 50%



A39
Zirconyl nitrate
Incompatibility with hydrogen





peroxide, not evaluated



A40
Tin IV oxide, 15%, 15 nm


Mar. 23, 2001
A41
Formamid Acetate



A42
Formamid Sulfinic Acid
Not evaluated due to unavailability





of raw materials



A43
Mayoquest 1320



A44
Mayoquest 2100



A45
Taurine



A46
Biuret



A47
Mayoquest 1200
Not evaluated due to unavailability





of raw materials
















TABLE 1b







Analysis of Variance for Removal












Source
DF
SS
MS
F
P





Slurry A
 36
2.827991
0.078555
227.07
0.000


Error
 74
0.025600
0.000346


Total
110
2.853591












Individual 95% CTs For Mean



Based on Pooled StD











Level
N
Mean
StDev
-----------+-----------+-----------+-----------





0
3
0.23667
0.00577
  *)


1
3
0.34667
0.01528
      (*)


2
3
0.40333
0.01155
       (*)


3
3
0.33333
0.02082
     (*)


4
3
0.29667
0.01528
    (*)


5
3
0.41333
0.02309
        (*


6
3
0.55333
0.03055
           (*)


7
3
0.25333
0.03055
   (*)


8
3
0.36667
0.00577
       (*)


9
3
0.42000
0.01000
        (*)


10
3
0.29333
0.01528
     (*)


11
3
0.06000
0.02646
 *)


12
3
0.24333
0.00577
   (*)


13
3
0.30000
0.02000
     (*)


15
3
0.21333
0.02309
  (*


17
3
0.55000
0.01732
           (*)


18
3
0.35667
0.00577
      (*)


19
3
0.46667
0.02887
         (*)


20
3
0.56333
0.02887
            (*


21
3
0.27333
0.00577
    (*)


23
3
0.56000
0.01000
            *)


24
3
0.38333
0.01528
      (*)


25
3
0.08667
0.00577
 *)


27
3
0.58667
0.01528
             *)


28
3
0.03000
0.00000
(*)


29
3
0.51000
0.01000
           *)


30
3
0.54333
0.00577
            (*)


31
3
0.73333
0.03055
               (*)


32
3
0.58000
0.01000
              (*)


34
3
0.27667
0.01155
    (*)


38
3
0.22000
0.00000
   (*)


40
3
0.28667
0.00577
    *)


41
3
0.50333
0.04619
            (*)


43
3
0.54000
0.01732
             (*


44
3
0.48333
0.02807
          (*)


45
3
0.25333
0.00577
  (*)


46
3
0.25667
0.00577
   (*)











Pooled StDev = 0.01860
-----------+-----------+-----------+-----------



   0.25   0.50   0.75






Table 1b, shows a myriad of possible constituents as candidates for slurry with adequate removal rate. Current state of the art colloidal silica slurries remove the nickel-phosphorous layer at rates from 7 mg-12 mg per minute per disk, which in comparison to this evaluation would equate to 0.252 g-0.432 g total removal. Table 1b shows thirteen slurries which surpass this current bench mark and have coded units of A6, A 17, A19, A20, A23, A27, A29, A30, A31, A32, A41, A43, and A44. In uncoded unites, these constituents are respectively aluminum nitrate, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), sodium fluorophosphate, hydroxyphosphono acetate, phosphoric acid, citric acid, glycine, lactic acid, oxalic acid, tartaric acid, formamid acetate, aminotri (methylenephosphonic acid) (ATMP) and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC). Each of these constituents in the presence of an oxidizer, (hydrogen peroxide in this specific example) show removal rate capabilities superior to the current state of the art.
Example 2
This example illustrates the effects and interactions of ten specific constituents. A fractional factorial design of experiment model was utilized to approximate the magnitude of interactions of ten constituents up through the third-order. This is to say that through statistical analysis of removal data, the effects individually and interactions with any one or two other constituents were evaluated. Process procedures, parameters and equipment were held constant as described in tables A and B to evaluate constituents with coded units A0, A5, A6, A17, A20, A23, A27, A29, A31 and A32. In uncoded units, those constituents were hydrogen peroxide, ethylene diamine, aluminum nitrate, HEDP, HPA, phosphoric acid, citric acid, glycine, oxalic acid and tartaric acid respectively. A design of experiment model of resolution four was utilized where the forty-two slurries were formulated according to table 2a. Further, this table describes the actual percent by weight each constituent was present in a given slurry. This is to say that in the first slurry evaluated, denoted by RunOrder 1, constituents A29, A31, A32 and A5 each were present in concentrations of 1 percent by weight of the total solution while A0 was present in 2.57 percent by weight of the total solution. Silica was held constant as described above at a percent by weight of 5.71 and the remaining weight percent was water.

















TABLE 2a





Run-












Order
A6
A17
A20
A23
A27
A29
A31
A32
A5
A0

























1
0
0
0
0
0
1
1
1
1
2.57


2
1
0
0
0
0
0
0
0
0
2.57


3
0
1
0
0
0
0
0
0
1
0.00


4
1
1
0
0
0
1
1
1
0
0.00


5
0
0
1
0
0
0
0
1
0
0.00


6
1
0
1
0
0
1
1
0
1
0.00


7
0
1
1
0
0
1
1
0
0
2.57


8
1
1
1
0
0
0
0
1
1
2.57


9
0
0
0
1
0
0
1
0
0
0.00


10
1
0
0
1
0
1
0
1
1
0.00


11
0
1
0
1
0
1
0
1
0
2.57


12
1
1
0
1
0
0
1
0
1
2.57


13
0
0
1
1
0
1
0
0
1
2.57


14
1
0
1
1
0
0
1
1
0
2.57


15
0
1
1
1
0
0
1
1
1
0.00


16
1
1
1
1
0
1
0
0
0
0.00


17
0
0
0
0
1
1
0
0
0
0.00


18
1
0
0
0
1
0
1
1
1
0.00


19
0
1
0
0
1
0
1
1
0
2.57


20
1
1
0
0
1
1
0
0
1
2.57


21
0
0
1
0
1
0
1
0
1
2.57


22
1
0
1
0
1
1
0
1
0
2.57


23
0
1
1
0
1
1
0
1
1
0.00


24
1
1
1
0
1
0
1
0
0
0.00


25
0
0
0
1
1
0
0
1
1
2.57


26
1
0
0
1
1
1
1
0
0
2.57


27
0
1
0
1
1
1
1
0
1
0.00


28
1
1
0
1
1
0
0
1
0
0.00


29
0
0
1
1
1
1
1
1
0
0.00


30
1
0
1
1
1
0
0
0
1
0.00


31
0
1
1
1
1
0
0
0
0
2.57


32
1
1
1
1
1
1
1
1
1
2.57


33
0
1
0
0
0
0
0
0
0
2.57


34
0
0
1
0
0
0
0
0
0
2.57


35
0
0
0
1
0
0
0
0
0
2.57


36
0
0
0
0
1
0
0
0
0
2.57


37
0
0
0
0
0
1
0
0
0
2.57


38
0
0
0
0
0
0
1
0
0
2.57


39
0
0
0
0
0
0
0
1
0
2.57


40
0
0
0
0
0
0
0
0
1
2.57


41
0
0
0
0
0
0
0
0
0
2.57


42
0
1
0
0
0
0
0
0
1
2.57









The quantitative results with respect to estimated effects and coefficients of this evaluation are found in table 2b. The coefficients denoted by “Coef” in table 2b indicate the magnitude of the effect of an individual constituent or interaction. The statistical significance of these results is described by a p-value which is denoted “P” in table 2b. A p-value less than 0.05 denotes a statistical significance. This is to say that when a p-value less than 0.05 is observed, these is sufficient statistical evidence to make inferences about the contribution of an individual constituent or interaction to the system with respect to removal rate.







TABLE 2b







Estimated Effects and Coefficients (coded units)












Term
Effect
Coef
SE Coef
T
P





Constant

0.3289
0.002580
123.60
0.000


A6
0.0156
0.0078
0.002580
3.03
0.003


A17
−0.0598
−0.0299
0.002589
−11.59
0.000


A20
0.0348
0.0174
0.002580
6.74
0.000


A23
−0.0127
−0.0064
0.002580
−2.46
0.016


A27
0.0281
0.0141
0.002580
5.45
0.000


A29
−0.0352
−0.0176
0.002580
−6.82
0.000


A31
0.0698
0.0349
0.002580
13.53
0.000


A32
−0.0677
−0.0339
0.002580
−13.12
0.000


A5
−0.0756
−0.0378
0.002580
−14.66
0.000


A0
0.3390
0.1685
0.002580
65.70
0.000


A6*A17
−0.0185
−0.0093
0.002580
−3.59
0.001


A6*A20
−0.0131
−0.0066
0.002580
2.54
0.013


A6*A23
0.0494
0.0247
0.002580
9.57
0.000


A6*A27
−0.0340
−0.0170
0.002580
−6.58
0.000


A6*A29
−1.0115
0.5057
0.024878
−20.33
0.000


A6*A31
−0.0140
−0.0070
0.002580
−2.71
0.008


A6*A32
0.0235
0.0118
0.002580
4.56
0.000


A6*A5
0.3246
0.1623
0.010319
15.73
0.000


A6*A0
−0.3925
−0.1962
0.011392
−17.23
0.000


A17*A20
0.0090
0.0045
0.002580
1.74
0.006


A17*A23
−0.0394
−0.0197
0.002580
−7.63
0.000


A17*A27
0.0698
0.0349
0.002580
13.53
0.000


A17*A29
0.0085
−0.0043
0.002580
−1.66
0.102


A17*A31
0.0131
0.0066
0.002580
2.54
0.013


A17*A32
0.4100
0.2050
0.013772
14.89
0.000


A17*A5
−0.1400
0.0700
0.007297
−9.59
0.000


A17*A0
−0.3748
−0.1874
0.010319
−18.16
0.000


A20*A23
0.0102
0.0051
0.002580
1.98
0.051


A20*A27
0.4994
0.2497
0.013772
18.13
0.000


A20*A29
1.1023
0.5511
0.025342
21.75
0.000


A20*A31
−0.5856
−0.2929
0.013772
−21.27
0.000


A20*A32
0.1665
0.0832
0.007297
11.41
0.000


A20*A5
−0.4369
−0.2184
0.013651
−16.00
0.000


A23*A27
0.0027
0.0014
0.002580
0.52
0.601


A23*A29
−0.0523
0.0261
0.002580
−10.14
0.000


A23*A31
0.1598
0.0799
0.007297
10.95
0.000


A23*A32
0.5769
0.2884
0.013092
20.76
0.000


A27*A29
0.2948
0.0974
0.007297
13.35
0.000


A27*A32
−1.0546
−0.5273
0.025210
20.92
0.000


A29*A32
−0.5333
−0.2667
0.01365.1
−19.53
0.000


A17*A20*A23
1.0433
0.5217
0.024744
21.08
0.000










Analysis of Variance for Sample (coded units)













Source
DF
Seq SS
Adj SS
Adj MS
F
P
















Main Effects
10
4.29746
3.25494
0.329494
515.73
0.000


2-Way
30
0.63745
0.67552
0.029184
45.68
0.000


Interactions


3-Way
1
0.28397
0.28397
0.283968
444.47
0.000


Interactions


Residual Error
84
0.05367
0.05367
0.000639


Pure Error
84
0.05367
0.05367
0.000639


Total
125
0.25655









The beneficial second order interactions obtained from this evaluation are as follows:
Beneficial Interactions


    HEDP:Ethylenediamine (slightly significant)
    Aluminum Nitrate:Tartaric Acid
    Aluminum Nitrate:Glycine
    Aluminum Nitrate:Phosphoric Acid
    Aluminum Nitrate:Glycine
    Phosphoric Acid:HPA (slightly significant)
    Citric Acid:HEDP
    HPA:Glycine
    Aluminum Nitrate:Ethylenediamine (slightly significant)
    Citric Acid:Ethylenediamine
    HPA:Glycine
    Citric Acid:HPA:Glycine
    HPA:Ethylenediamine
    Phosphoric Acid:Citric Acid
    Citric Acid:Glycine (slightly significant)


Example 3
Example 3 illustrates the effects and interactions more specifically of constituents, in coded units, A17, A20, A23, A27 and A29. These constituents in uncoded units are HEDP, HPA, phosphoric acid, citric acid and glycine respectively. Again, process procedures, parameters and equipment were held constant as described in tables A and B. Silica was present in each slurry at a concentration of 5.71 percent by weight of the total solution. Hydrogen peroxide in a 35 percent by weight solution was held constant in each slurry at a level of 2.57 percent by weight of the total solution. A fractional factorial design of experiment model was created to incorporate these chemistries. By so doing, nineteen slurries were formulated and quantitatively analyzed by examining removal rate data. The design of experiment model is defined in table 3a. A statistical analysis of this data is found in table 3b where the estimated effects and coefficients of individual constituents and interactions up through the fourth order are displayed.














TABLE 3a







Run Order
A17
A27
A29
A20
A23























1
0.1
0.1
0.1
0.1
0



2
1.1
0.1
0.1
0.1
0



3
0.1
1.1
0.1
0.1
0



4
1.1
1.1
0.1
0.1
0



5
0.1
0.1
1.1
0.1
0



6
1.1
0.1
1.1
0.1
0



7
0.1
1.1
1.1
0.1
0



8
1.1
1.1
1.1
0.1
0



9
0.1
0.1
0.1
1.1
0



10
1.1
0.1
0.1
1.1
0



11
0.1
1.1
0.1
1.1
0



12
1.1
1.1
0.1
1.1
0



13
0.1
0.1
1.1
1.1
0



14
1.1
0.1
1.1
1.1
0



15
0.1
1.1
1.1
1.1
0



16
1.1
1.1
1.1
1.1
0



17
1.0
1.0
0.0
0.0
1



18
1.0
1.0
0.0
0.0
1



19
1.0
1.0
0.0
0.0
1

















TABLE 3b







Estimated Effects and Coefficients for Sample (uncoded units)












Term
Effect
Coef
SE Coef
T
P





Constant

0.53518
0.007564
70.76
0.000


A17
0.05403
0.02701
0.002743
9.85
0.000


A27
0.02744
0.01372
0.002743
5.00
0.000


A29
−0.04166
−0.02083
0.003003
6.94
0.000


A20
−0.04533
−0.02266
0.003003
−7.55
0.000


A23
0.01349
0.00674
0.007677
0.88
0.385


A17*A27
−0.03435
−0.01717
0.002743
−6.26
0.000


A17*A29
−0.02003
0.01001
0.003003
−3.34
0.002


A17*A20
−0.03286
0.01643
0.003003
−5.47
0.000


A27*A29
−0.02727
−0.01364
0.003003
−4.54
0.000


A27*A20
−0.03460
−0.01730
0.003003
−5.76
0.000


A29*A20
−0.04084
−0.02042
0.003287
6.21
0.000


A17*A27*A29
0.03630
0.01817
0.003003
6.05
0.000


A17*A27*A20
0.03451
0.01726
0.003003
5.75
0.000


A17*A29*A20
0.04386
0.02193
0.003287
6.67
0.000


A27*A29*A20
0.03277
0.01639
0.003287
4.99
0.000


A17*A27*A29*A20
−0.00151
−0.00076
0.003287
−0.23
0.819










Analysis of Variance for Sample (coded units)













Source
DF
Seq SS
Adj SS
Adj MS
F
P





Main Effects
5
0.117544
0.100321
0.0200643
56.66
0.000


2-Way
6
0.049612
0.060841
0.0101402
28.63
0.000


Interactions


3-Way
4
0.049292
0.048996
0.0122491
34.59
0.000


Interactions


4-Way
1
0.000019
0.000019
0.0000187
0.05
0.819


Interactions









Table 3a depicts the levels at which each of the constituents were evaluated. For example, in addition to silica and hydrogen peroxide which were afore mentioned, slurry number 3, indicated by RunOrder 3, comprised 0.1 percent A17, 1.1 percent A27, 0.1 percent A29, 0.1 percent A20 and no A23. Each of the percentages described above are indicative of a percent by weight of the total slurry. The significance of this example is that A29 and A20 are shown to have an adverse effect on removal rate when in the presence of all the other constituents in this specific evaluation. Approximate values of said negative impacts in this specific system are found in table 3b and are characterized by their estimated coefficients; denoted by “Coef”.
Example 4
Example 4 depicts the effects of individual constituents and interactions of the preferred constituents in this invention. In coded units, these constituents are A0, A17, A23 and A27. Respectively, these constituents in uncoded units are hydrogen peroxide, HEDP, phosphoric acid and citric acid. All procedures, parameters and equipment were held constant as described in tables A and B. A fractional factorial design of experiment model was utilized to determine the magnitude of contributions with respect to removal rate of each constituent. The fractional factorial design of experiment model is portrayed in table 4a. Silica was present as 5.71 percent by total weight of each slurry. Ammonium hydroxide was utilized to standardize the pH throughout the evaluation at 2.5. Quantitative statistical analysis of the results of this example is available in table 4b. The concentrations of each constituent in each slurry is depicted in table 4a. For example, the first slurry evaluated, denoted by RunOrder 1, comprised of 0.25 weight percent A17, 0.25 weight percent A23, 0.27 weight percent A27 and 1.29 weight percent A0. Said weight percent values are indicative of total weight percent.











TABLE 4a





Run Order
A17
A23
A27
A0



















1
0.25
0.25
0.25
1.29


2
1.25
0.25
0.25
3.86


3
0.25
1.25
0.25
3.86


4
1.25
1.25
0.25
1.29


5
0.25
0.25
1.25
3.86


6
1.25
0.25
1.25
1.29


7
0.25
1.25
1.25
1.29


8
1.25
1.25
1.25
3.86
















TABLE 4b







Estimated Effects and Coefficients for Sample (coded units)












Term
Effect
Coef
SE Coef
T
P





Constant

0.59000
0.003773
156.37
0.000


A17
0.04167
0.02093
0.003773
5.52
0.000


A23
0.50000
0.02500
0.003773
6.63
0.000


A27
−0.02367
−0.01083
0.003773
−2.87
0.011


A0
0.03667
0.01833
0.003773
4.86
0.000


A17*A23
−0.03833
−0.01917
0.003773
5.88
0.000


A17*A27
0.00333
0.00167
0.003773
0.44
0.665


A17*A0
−0.00500
−0.00250
0.003773
−0.66
0.517










Analysis of Variance for Sample (coded units)













Source
DF
Seq SS
Adj SS
Adj MS
F
P





Main Effects
4
0.036300
0.036300
0.0090750
26.56
0.000


2-Way
3
0.009033
0.009033
0.0030111
8.81
0.001


Interactions


Residual Error
16
0.005467
0.005467
0.0003417


Pure Error
16
0.005467
0.005467
0.0003417


Total
23
0.050800









This example illustrates the significant interactions between the preferred constituents in this invention up through the second order.
Example 5
This example illustrates the performance capability of this invention. All process parameters and equipment were held constant as described in Tables A and B when slurry comprising hydrogen peroxide, citric acid, HEDP, phosphoric acid, ammonium hydroxide, silica and water was evaluated.
Thirty different runs were performed according to tables A and B. The removal and surface roughness data from these thirty runs were statistically analyzed. Removal rate data is portrayed graphically in FIG. 1 while surface roughness data is portrayed in FIG 2. The data acquired from this example depicts a mean removal rate of 18.37 mg/min/disk. Accompanying this mean removal rate is a standard deviation of 0.779 mg/min/disk. The surface of the nickel-phosphorous after polishing with this invention is void of defects. Defects are defined as any interruption in the nickel-phosphorous lattice having depth or height greater than twelve angstroms. This is observed through the surface roughness data obtained from this evaluation. A mean surface roughness of 1.47 angstroms was observed with a standard deviation of 0.17 angstroms. This value of 1.47 angstroms is indicative of the surface condition of the substrate. As measured on a TMS 2000, manufactured by Schmitt Inc., the average difference from peak to valley on the surface of the disks measured was 1.47 angstroms.
Table 5a:
Table 5b:
The chemistry utilized to obtain the data depicted in FIGS. 1 and 2 are by what the following claims are made.

## Claims

1. A CMP formulation which comprises a dispersion of abrasive particles with particle sizes from 15 to 80 nanometers and selected from the group consisting of silica, alumina, titania, ceria, zirconia and mixtures thereof dispersed in a formulation comprising:
a. an oxidant; 
b. a moderator of the action of the oxidizing agent which comprises a phosphate or phosphite group; 
c. a first accelerant comprising phosphonate groups; 
d. a second accelerant comprising amine or ammonium groups; and 
e. water.

2. A formulation according to claim 1 in which the formulation further comprises an organic carboxylic acid.

3. A formulation according to claim 2 in which the organic carboxylic acid is selected from the group consisting of citric acid, oxalic acid, lactic acid, tartaric acid, glycine and mixtures of such acids.

4. A formulation according to claim 3 in which the organic carboxylic acid is present in an amount that is from 2 to 10 wt % of the formulation.

5. A formulation according to claim 1 in which the abrasive particles are silica particles with a volume average particle size of 15 to 60 nanometers.

6. A formulation according to claim 1 in which the amount of abrasive in the formulation is from 2 to 10 wt % of the weight of the formulation.

7. A formulation according to claim 1 in which the oxidizing agent is selected from the group consisting of peroxides, periodates, percarbamates and mixtures thereof.

8. A formulation according to claim 7 in which the oxidizing agent is hydrogen peroxide in a concentration of from 0.1 to 6 wt % of the formulation weight.

9. A formulation according to claim 1 in which the moderator is selected from the group consisting of compounds having the group —POx, where x is from 1 to 4, and mixtures thereof.

10. A formulation according to claim 9 in which the moderator is present in the formulation in an amount that represents from 0.1 to 6 wt % of the formulation weight.

11. A formulation according to claim 1 in which the first accelerant is selected from the group consisting of 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), aminotri (methylenephosphonic acid) (ATMP), N-(2-hydroxyethyl)-N, N-di(methylenephosphonic acid) (HEMPA), 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) and mixtures thereof.

12. A formulation according to claim 11 in which the first accelerant is present in the formulation in an amount that i from 0.1 to 6 wt % of the formulation weight.

13. A formulation according to claim 1 in which the second accelerant is selected from the group consisting of ammonium hydroxide, ammonium salts such ammonium nitrate, urea, formamide acetate, biuret, ethylene diamine, glycine and mixtures of such compounds.

14. A formulation according to claim 13, in which the second accelerant is present in the formulation in an amount that is from 0.1 to 6 wt % of the formulation weight.

15. A process for the chemical-mechanical planarization of the surface of a nickel/phosphorus alloy containing from 9 to 12% of phosphorus which comprises polishing the surface in the presence of a slurry comprising a dispersion of abrasive particles with particle sizes from 15 to 60 nanometers and selected from the group consisting of silica, alumina, titania, ceria, zirconia and mixtures thereof dispersed in a formulation comprising:
a. an oxidant; 
b. a moderator of action of the oxidizing agent which comprises a phosphate or phosphite group; 
c. a first accelerant comprising phosphonate groups; 
d. a second accelerant comprising amine or ammonium groups; and 
e. water.

16. A process according to claim 15 in which an organic carboxylic acid is added to the formulation.

17. A process according to claim 16 in which the organic carboxylic acid is selected from the group consisting of citric acid, oxalic acid, lactic acid, tartaric acid, glycine and mixtures of such acids.

18. A process according to claim 17 in which the organic carboxylic acid is added to the formulation in an amount that is from 2 to 10 wt % of the formulation.

19. A process according to claim 18 in which the abrasive particles are silica particles with a volume average particle size of 15 to 60 nanometers.

20. A process according to claim 15 in which the amount of abrasive incorporated into the formulation is from 2 to 10% of the weight of the formulation.

21. A process according to claim 15 in which the oxidizing agent is selected from the group consisting of peroxides, periodates, percarbamates and mixtures thereof.

22. A process according to claim 21 in which the oxidizing agent is hydrogen peroxide in a concentration of from 0.1 to 6 wt % of the formulation weight.

23. A process according to claim 15 in which the moderator is selected from the group consisting of compounds having the group —POx, where x is from 1 to 4, and mixtures thereof.

24. A process according to claim 23 in which the moderator is present in the formulation in an amount that represents from 0.1 to 6 wt % of the formulation weight.

25. A process according to claim 15 in which the first accelerant is selected from the group consisting of 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), aminotri (methylenephosphonic acid) (ATMP), N-(2-hydroxyethyl])-N, N-di(methylenephosphonic acid) (HEMPA), 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) and mixtures thereof.

26. A process according to claim 25 in which the first accelerant is present in the formulation in an amount that is from 0.1 to 6 wt % of the formulation weight.

27. A process according to claim 15 in which the second accelerant is selected from the group consisting of ammonium hydroxide, ammonium salts such ammonium nitrate, urea, formamide acetate, biuret, ethylene diamine, glycine and mixtures of such compounds.

28. A process according to claim 27 in which the second accelerant is present in the formulation in an amount that is from 0.1 to 6 wt % of the formulation weight.