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Gel Porosity Test

IP.com Disclosure Number: IPCOM000082495D
Original Publication Date: 1974-Dec-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Bell, HF: AUTHOR [+2]

Abstract

The purpose of this test is to determine if a noncuprous metallic layer that is on a copper layer is pore-free. The test will detect the lower copper layer if the top layer is porous.

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Gel Porosity Test

The purpose of this test is to determine if a noncuprous metallic layer that is on a copper layer is pore-free. The test will detect the lower copper layer if the top layer is porous.

The test requires an indicator which is not only compatible in a gel medium, but can detect copper without detecting other metals present on the module as well.

Although benzidine hydrochloride meets this requirement, this reagent is listed on the carcinogenic chemical list and should not be used.

Neocuproine is a specific reagent for copper giving an orange-reddish colored compound. The test is very sensitive for cuprous ions even in the presence of any other cation. Traces of copper can be determined (0.005%) with this method.

Since only cuprous ions are specific for this reagent, it is necessary to add to the gel medium a reducing agent such as hydrazine or hydroxyl - ammonium chloride to reduce the cupric ions. The following is the preparation of the gel medium: 1) 9 gms of gelatin to 100 ml of boiling water; 2) 4% of electrolyte solution (10% Na(2)CO(3) soln. + 2% NaNO soln.); 3) 15 ml of indicator solution
(0.5 gm neocuproine in 15 cc isopropyl alcohol); and 4) 15 ml of reducing agent solution (15 gms of hydroxyl-ammonium chloride dissolved in 25 cc H(2)O or 15 ml of hydrazine).

The above ingredients are each mixed into the gel medium until they are dissolved. This is done after the 9 gms of gelatin have already dissolved in 100 cc of boiling H(2)O.

The sampl...