USP_6261635 (1063343), страница 3
Текст из файла (страница 3)
For example, inone embodiment, the liquid can be deposited to a thickness40diameter of greater than eight inches (up to and exceedingtWelve inches). In another embodiment, the liquid can bedeposited to a thickness that varies by no greater than aboutten Angstroms across the surface of the substrate 112, or theliquid can be deposited to thicknesses With other thicknessvariations on substrates 112 having other diameters.spinning at approximately the same rate as the substrate 112Furthermore, a liquid having a single viscosity can beused to produce layers on the substrate 112 having a greaterrange of thicknesses than is possible Without the barrier 140.For example, in one embodiment, a ?uid having a singleviscosity value of betWeen about ?ve centipoise and abouttWenty centipoise can be deposited on a substrate 112(having a diameter of greater than eight inches, up to andexceeding tWelve inches) to a selected uniform thicknessWithin a range of approximately 3,000 Angstroms.
In oneembodiment, a liquid having a viscosity of from about ?vecentipoise to about ten centipoise can be deposited on thesubstrate 112 to a thickness of from approximately 5,000The liquid supply conduit 123 then disposes the liquid ontoAngstroms to approximately 8,000 Angstroms by rotatingcollection vessel 120 via a drain tube 127. The collectionvessel 120 can also include an exhaust port 122 having anadjustable ?oW area to control a How of air past the substrate112 and out of the collection vessel 125.In a method in accordance With one embodiment of theinvention, he control arm 142 positions the barrier 140 onthe barrier support 134 and the substrate 112 and the barrier140 rotate together until the internal air volume 160 is50the upper surface 113 of the substrate 112, Where it ?oWsoutWardly under centrifugal force toWard the edges of thesubstrate 112.
In one aspect of this embodiment, the rotationspeed of both the substrate 112 and the barrier 140 can be upto 4,000 rpm, and in a further aspect of this embodiment, therotation speed can be in the range of from approximately2,000 rpm to approximately 4,000 rpm or some otherthe substrate 112 at a speed of from about 2,000 rpm to about55selected to produce the desired thickness can be selectedbased on such factors as evaporation rate of the liquid.
Inanother embodiment, the thickness can range from approximately 7,000 Angstroms to approximately 10,000 Ang60rotational velocity.In an alternate method, the liquid supply conduit 123 candispose the liquid on the substrate 112 before the substrate112 spins up to an initial, relatively loW speed Without thebarrier 140 in place. The initial rotation speed can beselected to be loWer than the loWest speed at Which the liquidforms non-uniformities With the adjacent air mass (for4,000 rpm.
The particular viscosity value and rotation ratestroms by depositing on the substrate 112 a liquid having aviscosity of from about ten centipoise to about tWentycentipoise and spinning the substrate at from about 2,000rpm to about 4,000 rpm. This is unlike some conventionaldevices, Which may require coupling the liquid supply65conduit 123 to a plurality of liquid sources (each having adifferent viscosity) to deposit liquid layers of differentthicknesses on different substrates 112.US 6,261,635 B187Another feature of the apparatus and methods discussedabove With reference to FIG.
3 is that the substrate 112 canbe supported in a manner that does not trap the ?uid againstthe loWer surface 114 of the substrate 112, While at the same112, While still alloWing the barrier 240 to rotate at the samerate as the substrate 112. Conversely, a feature of theapparatus 110 discussed above With reference to FIG. 3 isthat the barrier 140 Will alWays rotate at the same rate as thetime eliminating the need for rotating the collection vessel120, unlike some conventional apparatuses.
Accordingly, thesubstrate 112 When the barrier 140 is supported by thebarrier support 134, ensuring that the internal air volume 160loWer surface 114 of the substrate 112 can remain relativelyfree of contaminants While the liquid is disposed on theupper surface 113.
Furthermore, the apparatus 110 can besimpler to manufacture and operate because the collectionvessel 120 is ?xed relative to the motor 130, eliminating theneed for rotating seals betWeen the drain 121 and the drainline 127.FIG. 4 is a partially schematic, partially cutaWay sideelevation vieW of an apparatus 210 having a barrier 240 thatrotates independently of the substrate 112 in accordanceWith another embodiment of the invention.
The apparatusWill spin at the same rate as the substrate 112.From the foregoing, it Will be appreciated that, although10discussed above With reference to FIGS. 3 and 4 canseparate the other gases into an internal volume and an15external volume. Accordingly, the invention is not limitedexcept as by the appended claims.What is claimed is:1. A method for applying a liquid to a microelectronicsubstrate having a ?rst surface and a second surface facing210 can include a motor 230 having a drive shaft 232coupled to a substrate support 233 that supports the substrate112. The drive shaft is rotatable about an axis 236, asindicated by arroW A in a manner generally similar to thatspeci?c embodiments of the invention have been describedherein for purposes of illustration, various modi?cationsmay be made Without deviating from the spirit and scope ofthe invention.
For example, Where the environment adjacentthe substrate includes gases other than air, the barriers20opposite the ?rst surface, comprising:discussed above With reference to FIG. 3. The apparatus 210supporting the substrate by engaging less than the entirecan further include a collection vessel 220 disposed annusecond surface of the microelectronic substrate;disposing the liquid on the ?rst surface of the microeleclarly around the drive shaft 232 and the substrate 112 tocollect ?uid and to exhaust air, also in a manner generallysimilar to that discussed above With reference to FIG.
3.25tronic substrate;rotating the support and the microelectronic substrateThe barrier 240 can include a barrier shaft 247 thatabout a rotation axis at a ?rst rate to distribute the liquidextends upWardly and annularly around a liquid supplyover the ?rst surface of the microelectronic substrate;andconduit 223. The barrier shaft 247 can be coupled to a motor249 (for example, via gears 248a and 248b) to rotate thebarrier 240. Accordingly, the barrier 240 can rotate at a rateseparating a rotating ?rst volume of gas adjacent the ?rst30independent of the rate at Which the substrate 112 and thesubstrate support 233 rotate. In one aspect of thisally stationary second volume of gas proximate to the?rst volume of gas by positioning a barrier betWeen theembodiment, the rate at Which the barrier 240 rotates can bematched to the rate at Which the substrate 112 rotates so thatan internal air volume 260 Within the barrier 240 rotates With 35the barrier 240 and the substrate 112, While an external airvolume 250 remains approximately stationary, in a mannergenerally similar to that discussed above With reference toFIG.
3.In one embodiment, a ?ange 237 can be connected to the40drive shaft 232 and can extend radially outWardly beneaththe substrate support 233. The barrier 240 extends above and?rst and second volumes so that the barrier cover the?rst surface of the microelectronic substrate, and rotating the barrier at a second rate approximately equal tothe ?rst rate, Where the rotation of the barrier isrestricted relative to rotation of a barrier support positioned beneath the microelectronic substrate.2. The method of claim 1 Wherein rotating the barrierincludes rotating the barrier at from about 2,000 rpm toabout 4,000 rpm and distributing the liquid includes formingaround the substrate 112 and is spaced apart from the ?ange237 to de?ne an annular gap 238 betWeen the ?ange and thebarrier 240.
In one embodiment, a plurality of noZZles 270can be positioned in the gap 238 and can be coupled to asurface of the microelectronic substrate from a gener45source of cleaning ?uid 271. Accordingly, the noZZles 270can direct the cleaning ?uid toWard the loWer surface 114 ofa liquid layer having a thickness variation in the range offrom about ten Angstroms to about thirty Angstroms, furthercomprising selecting the microelectronic substrate to have acircular platform shape With a diameter of about tWelveinches.3.
The method of claim 1 Wherein disposing the liquid onthe ?rst surface of the microelectronic substrate includesplacing the liquid on the ?rst surface before rotating thethe substrate 112 to remove contaminants from the loWersurface. In one embodiment, the source 271 can be coupled 50 microelectronic substrate, and positioning the barrierto a temperature controller 272 to control the temperature ofincludes placing the barrier proximate to the substrate afterthe substrate 112 and the evaporation rate of the liquiddisposed on the upper surface 113 of the substrate 112.In a further aspect of the embodiment shoWn in FIG. 4, thegap 238 betWeen the barrier 240 and the ?ange 237 canthe substrate is rotating at the ?rst rate, further comprisingaccelerating both the microelectronic substrate and the bar55rier to rotate about the rotation axis at a third rate greaterthan the ?rst rate.extend outWardly beyond an outer edge 115 of the substrate4.
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