Abstract A four-step cleaning process is used for cleaning substrates, such as glass plates, to allow vacuum deposition of pinhole free films, such as chromium films for the fabrication of chromium masks, on the plates. The plates are first brush scrubbed in an aqueous bath. They are then ultrasonically pulsed in a second aqueous bath. The first and second aqueous baths may contain additives, such as sodium bicarbonate, to enhance the cleaning effect. The plates undergo an overflow rinse in purified water until a predetermined resistivity measurement, such as 8 megohms, is obtained. The plates are then spin dried. In the fabrication of chromium masks, a film of chromium is then vacuum evaporated or sputtered on the plates, followed by selective removal of chromium, such as by a photoresist and etching step, to give a desired image pattern.
A PROCESS FOR PROVIDING PINHOLE-FREE VACUUM DEPOSITED CHROMIUM FILMS ON A FIRST SURFACE OF GLASS SUBSTRATES CONSISTING OF THE STEPS OF: A. MECHANICALLY SCRUBBING ALL OF THE SURFACES OF A GLASS SUBSTRATE WHILE MAINTAINING SAID SUBSTRATE SUBMERGED IN A BATH SUBSTANTIALLY COMPRISING COLLOIDAL FREE DEIONIZED WATER, B. WASHING SAID SUBSTRATE IN AN ULTRASONICALLY PULSED BATH SUBSTANTIALLY COMPRISING COLLOIDAL FREE DEIONIZED WATER, C. RISING SAID SUBSTRATE IN A FLOWING COLLOIDAL FREE DEINOIZED WATER BATH UNTIL THE RESISTIVITY OF SAID RINSE WATER IS AT LEAST 8 MEGOHMS, D. SPIN DRYING SAID SUBSTRATE AFTER DISPENSING A QUANTITY OF COLLOIDAL FREE DEIONIZED WATER ON SAID FIRST SURFACE OF SAID SUBSTRATE, AND E. VACUUM DEPOSITING A THIN CHROMIUM FILM ON SAID FIRST SURFACE OF SAID SUBSTRATE.
Claim 2
Dependent Claim
121 words
A PROCESS FOR PROVIDING PINHOLE-FREE VACUUM DEPOSITED CHROMIUM FILMS ON A FIRST SURFACE OF GLASS SUBSTRATES CONSISTING OF THE STEPS OF: A. MECHANICALLY SCRUBBING ALL OF THE SURFACES OF A GLASS SUBSTRATE WHILE MAINTAINING SAID SUBSTRATE SUBMERGED IN A BATH SUBSTANTIALLY COMPRISING COLLOIDAL FREE DEIONIZED WATER, B. WASHING SAID SUBSTRATE IN AN ULTRASONICALLY PULSED BATH SUBSTANTIALLY COMPRISING COLLOIDAL FREE DEIONIZED WATER, C. RISING SAID SUBSTRATE IN A FLOWING COLLOIDAL FREE DEINOIZED WATER BATH UNTIL THE RESISTIVITY OF SAID RINSE WATER IS AT LEAST 8 MEGOHMS, D. SPIN DRYING SAID SUBSTRATE AFTER DISPENSING A QUANTITY OF COLLOIDAL FREE DEIONIZED WATER ON SAID FIRST SURFACE OF SAID SUBSTRATE, AND E. VACUUM DEPOSITING A THIN CHROMIUM FILM ON SAID FIRST SURFACE OF SAID SUBSTRATE.
Claim 3
Dependent Claim
23 words
The process of claim 1 wherein the baths in step (A) and in step (B) further include an additive comprising substantially sodium bicarbonate.
Claim 4
Dependent Claim
17 words
The process of claim 1 wherein said mechanical scrubbing step is carried out by a motorized brush.
Claim 5
Dependent Claim
17 words
The process of claim 1 wherein said thin chromium film is about 500 to 1000 angstroms thick.
Claim 6
Dependent Claim
24 words
The process of claim 4 including the additional step of defining a desired image pattern by selective removal of portions of said chromium film.