Quantitative Examination of Photofabricated Profiles^*

* Seconded from Research Division, Kodak Ltd., Harrow. MS received 1 September 1977.

Abstract

Part 1 of this series described an experimental procedure for following the development of edge profile of photoetched parts at all stages of the etching process. The procedure has now been used to study the etching of stainless steel: a metal with valuable properties but reputed to be difficult to handle. The depth of downward etching increased linearly with time, but with gaps in the resist narrower than 0.2 mm the rate decreased markedly with decreasing width. Sideways etching (undercut) also progressed linearly with time, but was less dependent on the line width. The results confirmed that the experimental procedure (described in Part 1) produced the desired data. Results obtained were consistent with current published statements about the state of the art. They provided data for adjustment of conditions needed to produce specified performance for a production run. In addition, comparison of results given by two different photoresists and two different etching baths demonstrated the ability to analyze changes of performance resulting from these differences.

Résumé

Une méthode de mesure des protons libérés dans une émulsion photographique a été utilisée pour étudier la sensibilisation Sulfurée. La formation de sulfure à partir de quantités normales de sensibilisateurs a été suivie en continu pendant la maturation. Avec la plupart des sensibilisateurs, les cinétiques de réaction sont du premier ordre, toutefois, dans certains cas, on observe une période d.induction. La formule de la réaction generalement admise pour le thiosulfate a été confirmée: Les résultats ne corroborent pas un mécanisme de sensibilisation faisant intervenir une réactivlte accrue au nlveau des germes de sensibilité.

Zusammenfassung

Eine Methode zur Messung der Proto~cnbildung in einer Photoemulsion wurde zur Bestimmung der schwefelsensibilisierungsreaktion angewandt. Die Sulfidbildung aus üblichen Mengen an Sensibilisator wurde kontinuier in der Reifemulsoin verflogt. Reaktionen von mehreren vershiedenen Sensibilisatoren folgten allgemein der Kinetik von Reaktionen erster Ordnung, Obwohl in enigen Fällen eine Induktionsperiode beobachtet wurde. Die allgemein bekannte Reaklion für Thiosulfat wurde bestätigt. Die Ergebnisse unterstützen nicht einen Sensibilisierungsmechanismus, der aufeiner bevorzugten Reaktion an den Empfindlichkcitskeimen beruht.

Riassunto

II metoda per misurare la formazione di protoni nelle cmulsioni fotografiche, è stato applicato alla misura c1ell’andamento della reazione di sensibilizzazione solforante.

La formazione di solfuro a partire da quantità convenzionali di sensibilizzatore solforante è stata seguita di continuo durante il tempo I maturazione dell’emulsione.

Le reazioni di alcuni sensibilizzatori di classi diverse genera Imente ubbidiscono alia cinetica di primo ordine; per quanto, in alcuni casi, la stato osservato un certo periodo di induzione. Comunque la reazione, generalmente indicata per it tiosolfato, è stata confermata.

I risultati, tuttavia, non convalidano I’idea di un meccanismo di sensibilizzazione interessantc anche un aumento di reazione dei centri di sensibilità.

Notes

* Seconded from Research Division, Kodak Ltd., Harrow. MS received 1 September 1977.