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Floatation Leveling of Parts at Elevated Temperatures

IP.com Disclosure Number: IPCOM000077576D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Costa, MJ: AUTHOR

Abstract

Processing of glass or ceramic substrates for electronic applications sometimes requires the formation of a thin film of protective glass or other dielectric material over the substrate. Following deposition of the film in powdered form, the temperature of the substrate is elevated to a point where the dielectric melts and reflows over the substrate making a contiguous seal to it. During the reflow step, the viscosity of the dielectric film can become low enough so that accurate leveling of the substrate is required if a film of uniform thickness is to be obtained.

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Floatation Leveling of Parts at Elevated Temperatures

Processing of glass or ceramic substrates for electronic applications sometimes requires the formation of a thin film of protective glass or other dielectric material over the substrate. Following deposition of the film in powdered form, the temperature of the substrate is elevated to a point where the dielectric melts and reflows over the substrate making a contiguous seal to it. During the reflow step, the viscosity of the dielectric film can become low enough so that accurate leveling of the substrate is required if a film of uniform thickness is to be obtained.

A method for automatically leveling parts which must be reflowed at elevated temperature operates as follows. Referring to Fig. 1, a tray 1 contains a relatively thin layer of tin 3. On top of the tin layer a flat hard glass or quartz support plate 5 is placed, and the container having substrates 7, 9, 11 thereon is placed in an oven for processing. When the oven reaches the melting point of tin (approximately 232 degrees C), the tin melts and support plate 5 floats on the molten tin and remains level despite out-of-level support of the tray itself. The relatively large surface area of the plate 5 and the high density of the tin 3 combine, to cause floatation buoyancy with little penetration of the plate into the tin. The substrates 7, 9, 11 are thus maintained level during the substrate processing at elevated temperatures. By utilizing a large supp...