Optimization of EDP solutions for feature-size-independent silicon etching

Kunchinadka Narayana Bhat; Chandana Yellempalle; Nandita DasGupta; Amitava DasGupta; Parimi Ramaseshagiri Rao

doi:10.1117/12.442978

28 September 2001 Optimization of EDP solutions for feature-size-independent silicon etching

Kunchinadka Narayana Bhat, Chandana Yellempalle, Nandita DasGupta, Amitava DasGupta, Parimi Ramaseshagiri Rao

Proceedings Volume 4557, Micromachining and Microfabrication Process Technology VII; (2001) https://doi.org/10.1117/12.442978
Event: Micromachining and Microfabrication, 2001, San Francisco, CA, United States

Abstract

The etching of single crystal silicon in ethylenediamine- pyrocatechol-water solutions (EDP) has been studied as a function of the composition of the etching solution. The solution with a constant composition of 7.5 ml of ethylenediamine (with 6g of pyrazine per liter) and 1.2g of pyrocatechol is used, and the water content is varied from 0 ml to 4 ml. Etch rate dependence on the active etching area is examined using three mask patterns having significantly different areas. It has been observed that etch rate depends significantly on the feature size in the solutions with higher water concentration and is almost independent of the area when the water content is 1 ml and below. Surface morphology was the other important criteria considered while optimizing the solution. Etch pit density (EPD) has been measured by etching the samples in different compositions to a constant depth of 45 micrometer. EPD is found to be high when the water content is above 2 ml and also when the amount of water is reduced below 0.5 ml. Minimal EPD is obtained when the water content is 0.5 ml. The optimized EDP solution containing 0.5 ml of water results in an etch rate of 44 micrometer/hr, independent of feature size and also good surface finish with EPD less than approximately 10³/cm².

Citation Download Citation

Kunchinadka Narayana Bhat, Chandana Yellempalle, Nandita DasGupta, Amitava DasGupta, and Parimi Ramaseshagiri Rao "Optimization of EDP solutions for feature-size-independent silicon etching", Proc. SPIE 4557, Micromachining and Microfabrication Process Technology VII, (28 September 2001); https://doi.org/10.1117/12.442978

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