| 摘要 |
1490828 Etching INTERNATIONAL BUSINESS MACHINES CORP 18 March 1976 [28 April 1975] 10949/76 Heading B6J [Also in Division G2] A semi-conductor wafer is etched while stationary and horizontal by metering sufficient etchant to form a miniscus-contained body of etchant over the whole upper surface of the wafer, detecting completion of the etching, and spinning the wafer to remove the etchant rapidly therefrom. The process can be used also to develop a photoresist mark before etching, and to strip the remaining resist after etching. The wafer support comprises three pegs 126 extending upwardly from a Y-shaped centrifugal chuck 12 supported on a shaft 11 for rotation by an air motor 13 and carrying three pivoted centrifugal arms which engage the edge of a wafer 18 when stationary and move clear of the edge when rotating. There is provided a set 15a of nozzles, namely, nozzles 51d for rinsing water, 42d for developer liquid, 46d for etchant, and 62d for resist stripper liquid, mounted on a block 72 slidable in a cylinder 70 by means of springs 71 and air pressure applied to a piston rod 73 so as to bring the nozzles over the wafer or to a non-operative position to the right thereof. The nozzles are also connected by a bracket 34 which also supports an end-ofetching detector 35 comprising a laser source 26, a photo-electric cell 27 and optical fibre members 31, 32. Metered quantities of fluids are delivered to the nozzles, the shaft 11 is rotated, and the nozzles are moved under the control of a programmable controller 36, which receives signals from the photoelectric cell 27. In a complete developing, etching and stripping process, a wafer covered with a layer of photo-resist which has been selectively hardened by exposure to light but not developed, is placed on the chuck, the nozzles are moved over the wafer, and sufficient developer is supplied to form a meniscus-contained body 19. After development, the nozzles are again moved over the wafer and deionized water supplied to rinse away the loose resist, the chuck is rotated to spin off the remaining resist and spray, and a baking element 22 is actuated to dry the assembly. After stopping the rotation, buffered HF etchant is similarly supplied, and on detection of completion of etching, the chuck is immediately rotated while rinse liquid is supplied, to remove all traces of etchant. The process is repeated with a stripping liquid such as hot sulphuric acid to remove the remaining photo-resist, followed again by rinsing and drying. The water is removed and may have a further layer required to be etched formed on it, and the entire process repeated. The layer to be etched may be silicon dioxide, polycrystalline silicon, silicon nitride, aluminium or sputtered quartz, supported on a silicon substrate. |
