Pad testing

A polishing pad has a significant impact on the performance of the CMP process. It transports the slurry to the pad-wafer interface, impacts the polishing nonuniformity, and affects the global wafer and device planarity. Pads may consist of thin porous closed cell [28], open cell [29], or noncell [30] polyurethane material. The properties of polishing pad can be studied in detail 

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The testing procedure tor well pad test separators is essentially the sane as with GC test separators. The HOC operator aelects the well to be tested and interlocked logic operates the well pad diverter valves to divert the well Into the test vessel. 

FIGURE 2.10 Correlation between standard deviations of nanotopography and film thickness variation for soft pad test. 

FIGURE 2.12 Power spectral densities for (a) soft pad test and (b) hard pad test. 

Copper-constantan thermocouples were embedded in the babbitt facing in all six of the pads tested, at the following locations ... 

Figure 10. Friction coefficient for a tilting pad tested against a glass disc.

Method 2. Mix 1 0 g. of 3 5-dinitrobenzoic acid with 1 5 g. of phosphorus pentachloride in a small, dry test-tube. Warm the mixture gently over a small smoky fiame to start the reaction when the reaction has subsided (but not before), boil for 1-2 minutes or until the solid matter has dissolved. Pour the mixture while still liquid on a dry watch glass (CAUTION the fumes are irritating to the eyes). When the product has solidified, remove the liquid by-product (phosphorus oxychloride) by transferring the pasty mixture to a pad of several thicknesses of filter paper or to a small piece of porous tile. Spread the material until the liquid has been absorbed and the residual solid is dry. Transfer the 3 5 dinitrobenzoyl chloride to a test-tube, add 0-5-1 ml. of the alcohol, and continue as in Method 1. 

Add 1 ml. of the alcohol-free ether to 0-1-0-15 g. of finely-powdered anhydrous zinc chloride and 0 5 g. of pure 3 5-dinitrobenzoyl chloride (Section 111,27,1) contained in a test-tube attach a small water condenser and reflux gently for 1 hour. Treat the reaction product with 10 ml. of 1-5N sodium carbonate solution, heat and stir the mixture for 1 minute upon a boiling water bath, allow to cool, and filter at the pump. Wash the precipitate with 5 ml. of 1 5N sodium carbonate solution and twice with 6 ml. of ether. Dry on a porous tile or upon a pad of filter paper. Transfer the crude ester to a test-tube and boil it with 10 ml. of chloroform or carbon tetrachloride filter the hot solution, if necessary. If the ester does not separate on cooling, evaporate to dryness on a water bath, and recrystallise the residue from 2-3 ml. of either of the above solvents. Determine the melting point of the resulting 3 5 dinitro benzoate (Section 111,27). 

As a vessel is loaded, it moves downward because of deflection of the load cells and support stmcture. Pipes rigidly attached to a vessel restrict its free movement and assume some portion of the load that cannot be measured by the load cells. This is very detrimental to scale accuracy. Deflection of the load cell is unavoidable deflection of the vessel support stmcture should be minimized. Anything which increases vessel deflection, eg, mbber pads used for shock protection, must be avoided. The total number of pipes should be minimized and be of the smallest diameter, thinnest wall possible. Pipe mns to weigh vessels must be horizontal and the first pipe support should be as far as possible from the vessel. Alternatively, a section of mbber hose or flexible bellows should be used to make the final connection to the vessel. The scale should be caUbrated using weights, not by means of an electrical simulation method, which cannot account for the effects of the piping or test the correct functioning of the scale. 

THPC—Amide—PoIy(vinyI bromide) Finish. A flame retardant based on THPC—amide plus poly(vinyl bromide) [25951-54-6] (143) has been reported suitable for use on 35/65, and perhaps on 50/50, polyester—cotton blends. It is appUed by the pad-dry-cure process, with curing at 150°C for about 3 min. A typical formulation contains 20% THPC, 3% disodium hydrogen phosphate, 6% urea, 3% trimethylolglycouril [496-46-8] and 12% poly(vinyl bromide) soUds. Approximately 20% add-on is required to impart flame retardancy to a 168 g/m 35/65 polyester—cotton fabric. Treated fabrics passed the FF 3-71 test. However, as far as can be determined, poly(vinyl bromide) is no longer commercially available. 

LRC-100Finish. The use of LRC-100 flame retardant for 50/50 polyester cotton blends has been reported (144). It is a condensation product of tetrakis(hydroxymethyl)-phosphonium salt (THP salt) and A/A7,A7 -trimethylphosphoramide [6326-72-3] (TMPA). The precondensate is prepared by heating the THP salt and TMPA in a 2.3-to-l.0-mole ratio for one hour at 60—65°C. It is appUed in conjunction with urea and trimethylolmelamine in a pad-dry-cure oxidation wash procedure. Phosphoms contents of 3.5—4.0% are needed to enable blends to pass the FF 3-71 Test. 

Shipment and Storage. The weight per gallon is 5.6 kg. MSG is shipped and stored in 55-gaHon (0.208 m ) steel dmms or 5-gaHon (0.02 m ) steel pads with a polyethylene liner. Anhydrous MSC is also corrosive toward titanium, titanium—palladium, and zirconium as measured in metal strip tests at 50°C. It is classified as a corrosive Hquid. 

Flame Retardants. The amount of research expended to develop flame-retardant (FR) finishes for cotton and other fabrics has been extremely large in comparison to the total amount of fabrics finished to be flame retardant. The extent of this work can be seen in various reviews (146—148). In the early 1960s, a substantial market for FR children s sleepwear appeared to be developing, and substantial production of fabric occurred. In the case of cotton, the finish was based on tetrakis(hydroxymethyl)phosphonium chloride (THPC) or the corresponding sulfate (THPS). This chemical was partly neutralized to THPOH, padded on fabric, dried under controlled conditions, and ammoniated. The finish was subsequently oxidized, yielding a product that passed the test for FR performance. This process is widely preferred to the THPOH—NH process. 

These problems can be dealt with by usiag artificial test cloths impregnated with various approximations of natural soils such as vacuum cleaner dust, dirt from air conditioner filters, clays, carbon black, fatty acids, dirty motor oil, and artificial sebum, either alone or ia combination (37,94—98). The soils are appHed by sprayiag, immersion, or padding. If the soils are carefully appHed, reproducible results can be obtained. Soil test cloths can be of great help ia detergency studies, when used with an understanding of their limitations. 

FIG. 10 123 Difference in total-power-loss data test minus catalog frictional losses versus shaft speed for 6 X 6 pad doiihle-element thrust hearings. 

Before taking the sample train to the test site, it is wise to prepare the operating curves for the particular job. With most factory-assembled trains, these curves are a part of the package. If a sampling train is assembled from components, the curves must be developed. The type of curves will vary from source to source and from train to train. Examples of useful operating curves include (1) velocity versus velocity pressure at various temperatures (6), (2) probe tip velocity versus flowmeter readings at various temperatures, and (3) flowmeter calibration curves of flow versus pressure drop. It is much easier to take an operaHng point from a previously prepared curve than to take out a calculator and pad to make the calculahons at the... 

King, T.F., and Capitao, J.W., Impact on Recent Tilting Pad Thrust Bearing Tests on Steam Turbine Design and Performance, Proceedings of the 4th Turbomachinery Symposium, Texas A M University, October 1975, pp. 1-8. 

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