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Etching Solution

IP.com Disclosure Number: IPCOM000090451D
Original Publication Date: 1969-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Currier, EW: AUTHOR [+2]

Abstract

Formation of electrodes by subtractive etching on integrated circuit devices bearing typical films of deposited Al/Si normally produces a black Formation of electrodes by subtractive etching on integrated circuit devices bearing typical films of deposited Al/Si normally produces a black granular deposit. This residue must be removed before the device is further processed. Vigorous rubbing with microcloth usually is sufficient, but some smearing or destruction of the Al/Si electrodes results. Sometimes the residue cannot be rubbed away, and then significant yield losses are to be expected. The conventional etching solution is composed of, in percentages by volume, H(3)PO(4) 80% HNO(3) 5% CH(3)COOH 5% Deionized water 10%.

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Etching Solution

Formation of electrodes by subtractive etching on integrated circuit devices bearing typical films of deposited Al/Si normally produces a black Formation of electrodes by subtractive etching on integrated circuit devices bearing typical films of deposited Al/Si normally produces a black granular deposit. This residue must be removed before the device is further processed. Vigorous rubbing with microcloth usually is sufficient, but some smearing or destruction of the Al/Si electrodes results. Sometimes the residue cannot be rubbed away, and then significant yield losses are to be expected. The conventional etching solution is composed of, in percentages by volume, H(3)PO(4) 80% HNO(3) 5% CH(3)COOH 5% Deionized water 10%.

The deposited residue described is an indeterminate mixture of Si, Al, and SiO(2), as shown by chemical analysis.

The disadvantages mentioned can be eliminated by adding to the etching solution about 1% by volume of the cationic wetting agent, 1-Hydroxyethyl-2- Heptadecenylglyoxalidine. The residue is still formed with this new solution, but it now can be readily removed by gentle rubbing with microcloth. Ultrasonic rinsing with deionized water removes 95% of the residue. Concentrations of the wetting agent as low as 0.1% by volume are effective. The upper limit of concentration is set only by the solubility of the wetting agent in the etching solution.

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