Abrasive particle size

Faust (1.3) used die etching rate method on both german-ium and silicon and covered a wide range of abrasive particle sizes. Some of his data are shown in Fig. 5 (14), He found that for a given abrasive treatment the depth of damage on silicon was about one fourth that on germanium. 

Fig. 5. Depth of damage on germanium and silicon as a function of abrasive particle size. O Etching rate method (14). Data from references 11 and lb After Faust...

EFFECT OF ABRASIVE PARTICLE SIZE ON REMOVAL RATE AND DEFECTIVITY... 

A second possibility is that the dislodged fragments could be adsorbed onto the abrasive particles surfaces. According to Cook, this removal mechanism dominates in the CMP of SiOz (Section 4.2). If such a deposition process does not significantly affect the abrasive particle size, suspension behavior, or abrasive... 

The effect of slurry abrasive size on polish rate is not very clear. Different results have been reported for oxide polishing showing contradicting conclusions. Results obtained by Jairath et al. [S] suggested that the oxide polish rate increases with both abrasive particle size and concentration. However, other reports found that glass polish rate is constant with abrasive size [6], [7] or even decreases with abrasive size [8]. 

The majority of engineering materials are heterogeneous, composed of phases with considerable differences in hardness. When an abrasive particle is small, the presence of coarse, hard, phases in these alloys can considerably strengthen the material s resistance to abrasive wear. But if the abrasive particle size is comparable to the scale of heterogeneity of the material, then gouging out the hard material from the structure leads to an increased wear rate. Abrasion can be limited by ... 

Abrasive Particle size Density Hardness CrystaJ... 

FIGURE 3.25 (a) Abrasive particle size distribution without surfactant addition and (b) average median (djo) abrasive size as a function of the surfactant molecular weight at pH 6.5 to 7.0. 

The movement of streams of granular solids horizontally and/or vertically is achieved with conveyors and elevators. When selecting the type of equipment, important considerations aie stickiness, abrasiveness, particle size, and density of the solid particles. 

Three-body contact scale ( 100 nm) is close to a single abrasive particle size. The three interactive bodies are the wafer, the abrasive particle, and the pad asperity. The wafer and particles are more rigid than the pad asperities, so that the main deformation occurs within the asperity. 

CMP slurries are formulated with a combination of abrasive particles and chemical additives as summarized in Table 10.1. The additives are selected for their ability to stabilize the abrasive particle dispersions, and optimize the selective removal of the materials targeted by a particular CMP operation. With few exceptions, the abrasive particles used in commercial CMP slurries for semiconductor applications are comprised of alumina, ceria, or amorphous silica (Al203 Ce02, Si02). Depending on the particular application, the abrasive particle sizes in CMP slurries may typically vary over a range from approximately 20 to 200 nm. Particles and/or agglomerates of... 

The characteristics of slurry such as abrasive particle size and distribution, surface chemistry, dispersion stability, and rheological behavior are determined by the complex interaction between its components, and have significant influence on CMP performances. 

Among various characteristics of the slurry, abrasive particle size has significant influence on MRR. There are two models, contact area model and indentation volume model, to explain it. At the small abrasive parficle, the contact area model is dominant. As abrasive size increases, the indentafion volume model becomes more appropriate (Basim et al., 2000). According to Cook s hypothesis, the active sites on the abrasive surface also play a key role in MRR. These active sites are influenced by various physicochemical conditions including pH, ionic strength, temperature, and concentration. Rheological behavior of CMP slurries is also important because their mass transport on the pad can effect three-body (slurry—pad—wafer) interaction. Hence, it is very important to imderstand the characteristics of slurry because they have significant influence on CMP performances. 

Surface roughness depends on abrasive particle size. 

Diamond (abrasive) The crystalline form of carbon that is very hard. Commonly available in abrasive particle sizes down to 0.25 micron. 

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