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Surface Characterization by Droplet Evaporation

IP.com Disclosure Number: IPCOM000076417D
Original Publication Date: 1972-Feb-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Bickford, HG: AUTHOR [+3]

Abstract

The apparatus permits quick and easy testing of surface characteristics on a semiconductor wafer 24, by in-process monitoring of surface treatments. Thus, it is possible to test the suitability of the surface for photoresist application, then treat the surface further if it is shown to be unsuitable.

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Surface Characterization by Droplet Evaporation

The apparatus permits quick and easy testing of surface characteristics on a semiconductor wafer 24, by in-process monitoring of surface treatments. Thus, it is possible to test the suitability of the surface for photoresist application, then treat the surface further if it is shown to be unsuitable.

The apparatus includes heater 18, heat sink 20 and thermocouple 21 for establishing controlled temperature conditions, a nitrogen input 15 and desiccant 12 for establishing a controlled atmosphere within chamber 13. Dispensing mechanism 26 supplies through syringe needle 30 a known quantity of liquid, such as water, in a droplet 42 on surface 24. The surface is characterized by determining the evaporation rate of liquid from it under the controlled conditions. This is usually done by measuring the time for complete evaporation of the droplet, as observed through transparent cover 14.

For water droplets, evaporation rate is found an excellent measure of the hydrophobic or hydrophilic nature of the surface. With different contact angles, different shape droplets are formed. Evaporation rate is dependent on surface area of the droplet contacting the atmosphere. Different evaporation rates of same quantity of liquid under same conditions from different surfaces is an indication of different contact angles. In general, the more hydrophilic is surface 24, the more spread out is the droplet and the shorter is the evaporation t...