Performance Evaluation And Self-conditioning Of Fixed-abrasive Pad

With the flourish of optics, optoelectronics, digital products and IC industry, hard-brittle materials with super-smooth surface are largely demanded, ultra-precision machining techniques are required. As the right method, Chemical Mechanical Polishing (CMP) is capable of obtaining global planarizaion with ultra-precision and high-quality surface based on molecular or atom scale materail removal. However, the conventional CMP has many problems such as low efficiency, high cost, severe pollution, and bad process stability, et al. Therefore, fixed-abrasive CMP (FA-CMP) is proposed.In this paper, a method of fixed abrasive pad (FAP) was developed through pattern transfer and UV curing process. The main work and results on FAP are as follows:1. Swelling ratio and pencil hardness were selected to evaluate the matrix properties of FAP through single factor experiment. Results show that swelling ratio of FAP rises with the decrease of film thickness and increase of swelling time. TMPTA is the most effective factor, with the decrease of its content, swelling ratio drops and wet pencil hardness rises dramatically. Meanwhile, with the decrease of content of PEGDA, EO15-TMPTA or PUA, swelling ratio rises and wet pencil hardness drops. And, pH value and CI are the non-significant factors to matrix properties in this experiment.2. Material removal rate (MRR) and 3D-profile surface roughness (Sa) were selected to evaluate machining performance of FAP. The performance of conventional lapping, fixed abrasive pellet lapping, and hydrophilic FAP lapping were compared. It shows that the surface quality obtained by FAP is much better than the former two, and a material removal model of hydrophilic FAP is suggested. Besides, single factor experiment was employed to explore the effect of parameters on machining performance in FA-CMP. Results show that MRR slightly decreases with time passing. Large eccentricity, alkaline slurry, and high rotational speed are helpful to improve MRR. While in certain range, applied pressure and slurry flow have little effect on MRR. With the increase of abrasve size, MRR rises significantly and Sa drops. Different materials show differnt machining performance when FAP employed.3. The relationship between matrix properties and machining performance of FAP was studied by means of lapping and polishing experiments with 10 different kinds of FAPs. Self-conditioning capability was verified through the marathorn-run experiment. Results show that with the drop of swelling ratio, MRR decreases and Sa increases. When swelling ratio is less than 1.60%, Sa decreases with the drop of wet pencil hardness, while it will decrease with the rise of wet pencil hardness. Some FAPs with the right swelling ratio have self-conditioning capacity.And finally, the further work on the theory and technology of FAP is prospected.