Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Measuring the Layer Thickness of Extremely Thin Silicon Films

IP.com Disclosure Number: IPCOM000078444D
Original Publication Date: 1973-Jan-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 3 page(s) / 18K

Publishing Venue

IBM

Related People

Briska, M: AUTHOR [+2]

Abstract

In order to reduce the alloying of aluminum into the contact surfaces of flat diffusion components, the copper-aluminum layer vapor deposited on a silicon wafer is predoped with silicon before vapor depositing the copper-aluminum layer. This doping can be performed either by homogeneously introducing the Si into the Cu-Al film or by establishing a thin underlay (multilayer metallurgy). The layer thickness h of this extremely thin silicon layer is determined according to the formula h = G over F.rho', where G is the analytically determined silicon quantity in g, F is the film area in cm/2/, and rho is the silicon density equalling 2.49 g/cm/3/.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 3

Measuring the Layer Thickness of Extremely Thin Silicon Films

In order to reduce the alloying of aluminum into the contact surfaces of flat diffusion components, the copper-aluminum layer vapor deposited on a silicon wafer is predoped with silicon before vapor depositing the copper-aluminum layer. This doping can be performed either by homogeneously introducing the Si into the Cu-Al film or by establishing a thin underlay (multilayer metallurgy). The layer thickness h of this extremely thin silicon layer is determined according to the formula h = G over F.rho', where G is the analytically determined silicon quantity in g, F is the film area in cm/2/, and rho is the silicon density equalling
2.49 g/cm/3/.

The silicon quantity in g is colorimetrically determined by the silico-molybdenum blue method.

Method Reagents:
a) 10 % aqueous solution of NaOH,
b) 20 % aqueous solution of H(2)SO(4),
c) 20 % aqueous solution of tartaric acid,
d) ammonium molybdate solution:

25 g of the reagent [ (NH(4))(6)MO(7)O(24). 4H(2)O) ]

are dissolved in 200 ml of water, mixed with 20 ml of

H(2)SO(4) (1.84) and adjusted with water to 250 ml.
e) Reducing solution: 5.4 g of Na(2)S(2)O(5) are dissolved in 40 ml of

water, 0.4 g of NaOH and 0.1 g of 1-amino-2

naphthol-4-sulfonic acid are dissolved in 5 ml

of water; both solutions are mixed and adjusted

with water to 50 ml.

A 0.02 mm thick foil of 99.999 % Al, with an area of 16 cm/2/ together with silicon wafers is subjected to film deposition in a suitable apparatus. Before and after vapor deposition the foil is weighed to determine the weight of the vapor deposited layer (CuAl+Si). Then the Al monitor foil is completely dissolved at 60 degrees C in 20 ml of NaOH solution in a plastic watch glass covered silver bowl, adding abt. 15 ml of water and keeping the solution simmering for abt. 20 min. After cooling, the sample is transferred to a 250 ml polyethylene beaker, adding H(2)S)(4) solut...