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Electropolishing Semiconductor Wafers

IP.com Disclosure Number: IPCOM000096631D
Original Publication Date: 1963-Sep-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Krajicek, JS: AUTHOR [+2]

Abstract

In the fabrication of semiconductor devices, it is important to employ semiconductor wafers having flat, smooth, damage-free surfaces, particularly in connection with wafers to be employed in diffusion operations. This electropolishing technique and apparatus are useful in preparing the surfaces of such wafers, especially N-type silicon wafers which heretofore were considered to require heat or light to produce electron-hole pairs for the electropolishing operation.

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Electropolishing Semiconductor Wafers

In the fabrication of semiconductor devices, it is important to employ semiconductor wafers having flat, smooth, damage-free surfaces, particularly in connection with wafers to be employed in diffusion operations. This electropolishing technique and apparatus are useful in preparing the surfaces of such wafers, especially N-type silicon wafers which heretofore were considered to require heat or light to produce electron-hole pairs for the electropolishing operation.

Wafer 10 of a semiconductor material such as silicon, having a gold-wool contact 11 temporarily secured to a portion of one surface, is held in engagement with a plastic rotor 12 by means of a partial vacuum. The vacuum is developed at the upper surface of the wafer by a vacuum line 13. This is connected to a vertically extending conductive sleeve 14. Such is press-fitted into central bore 15 in rotor 12. Brush and slip ring assembly 16 is connected between the positive terminal of DC power supply 17 and conductive sleeve 14. The latter serves as the anode in an electrolyte. Motor 18 and gear system 19 turn rotor 12 and wafer 10 which is held in engagement with it.

Rotor 12 is confined in the upper portion of plastic housing 20. This also supports stainless steel cathode 21 in its lower portion. Cathode 21 is connected to the negative terminal of power supply 17. It is arranged so that its upper face is disposed a predetermined distance from the lower face of roto...