USP_20010020443 (1063353), страница 2
Текст из файла (страница 2)
The variation in heat transfer ratesinclude a collection vessel 20a ?xed relative to the motorconvective heat transfer rate can vary over the surface of theSep. 13, 2001US 2001/0020443 A130a and having a drain 21 and an exhaust port 22 forremoving liquid and gas from the region adjacent to thesubstrate 12.[0010]One problem With the device 10a shoWn in FIG. 2is that the liquid disposed on the substrate 12 can becometrapped betWeen the loWer surface of the substrate 12 and theWalls of the recess 36 into Which the substrate 12 is placed.A further draWback is that the recess 36 is siZed for rectangular substrates 12, making it unsuitable for or unusableWith round substrates, particularly Where the diameter of theround substrate exceeds the Width of the recess 36.SUMMARY OF THE INVENTION[0011]The present invention is directed toWard methodsand apparatuses for uniformly distributing a liquid over asurface of a spinning microelectronic substrate.
An apparatus in accordance With one aspect of the invention caninclude a support having an engaging portion for engagingthe microelectronic substrate and rotating the microelectronic substrate at a ?rst rate. The microelectronic substratecan have a ?rst surface that receives the liquid and a secondsurface facing opposite the ?rst surface With the engagingportion con?gured to engage less than the entire secondsurface.
Arotating barrier proximate to the support rotates ata second rate approximately equal to the ?rst rate to separatea ?rst portion of gas adjacent the microelectronic substrateand rotating With the microelectronic substrate from a second portion of gas spaced apart from the microelectronicsubstrate and generally stationary relative to the microelectronic substrate.[0012]In a method in accordance With an aspect of theinvention, a liquid having a single viscosity can be distributed over the ?rst surface of the substrate to a generallyuniform thickness ranging from a ?rst value to a secondmicroelectronic substrates and/or substrate assemblies.Many speci?c details of certain embodiments of the invention are set forth in the folloWing description and in FIGS.3 and 4 to provide a thorough understanding of suchembodiments.
One skilled in the art, hoWever, Will understand that the present invention may have additionalembodiments, or that the invention may be practiced Withoutseveral of the details described in the folloWing description.[0018] FIG. 3 is a partially schematic, partially cutaWayside elevation vieW of an apparatus 110 that spins a substrate112 and a barrier 140 at approximately the same rate todistribute a liquid over the substrate 112 in accordance Withan embodiment of the invention. The substrate 112 can havea generally round planform shape and a diameter of at leastapproximately eight inches. For example, in one embodiment, the substrate 112 can have a diameter of approximately tWelve inches and in other embodiments the substrate112 can have other diameters and shapes so long as it can beadequately supported by the apparatus 110 and so long as theliquid can be distributed on the substrate 112 in a uniformmanner.[0019]The apparatus 110 can include a motor 130 coupledWith a drive shaft 132 to a support assembly 131 to rotate thesupport assembly about an axis 136 as indicated by arroW A.The support assembly 131 can include a substrate support133 that supports the substrate 112 such that an uppersurface 113 and an outer portion of a loWer surface 114 ofthe substrate 112 are exposed.
Accordingly, the substratesupport 133 can have a lateral extent perpendicular to theaxis 136 that is less than the lateral extent of the substrate112 in the same direction, i.e., the substrate 112 can overhang the substrate support 133.[0020]The support assembly 131 can further include avalue approximately 3,000 Angstroms greater than the ?rstbarrier support 134 that extends radially outWardly beyondvalue by positioning a barrier to separate a rotating ?rstvolume of gas adjacent the ?rst surface from a generallythe substrate support 133 and the substrate 112 to supportand rotate the barrier 140 as the support assembly 131stationary second volume of gas.
For example, the 3,000rotates. The barrier support 134 can include a plurality ofAngstrom range can extend from about 5,000 Angstroms toabout 8,000 Angstroms, or from about 7,000 Angstroms toabout 10,000 Angstroms. The viscosity can be selected to befrom about six centipoise to about tWenty centipoise and theliquid can be distributed to a thickness that varies by lessspaced apart stanchions 135 to restrict radial motion of thebarrier 140 relative to the barrier support 134.
Alternatively,the barrier 140 can rotate independently of the substrate 112,than tWenty Angstroms.BRIEF DESCRIPTION OF THE DRAWINGS[0013] FIG. 1 is a partially schematic, partially cutaWayside elevation vieW of an apparatus in accordance With theprior art.[0014] FIG. 2 is a partially schematic, partially cutaWayside elevation vieW of another apparatus in accordance Withthe prior art.as Will be discussed in greater detail beloW With reference toFIG. 4.[0021] In one embodiment, the barrier 140 has a generallycircular planform shape and extends around and over thesubstrate 112 to separate a stationary, external air volume150 outside the barrier 140 from a rotating, internal airvolume 160 inside the barrier 140.
Accordingly, the barrier140 can be coupled to the drive shaft 132 via the barriersupport 134 to spin at the same rate as the substrate 112. Thebarrier 140 can include an upper Wall 145 facing andgenerally parallel to the upper surface 113 of the substrate[0015] FIG. 3 is a partially schematic, partially cutaWay112. The barrier 140 can also include sideWalls 144 extendside elevation vieW of an apparatus in accordance With aning doWnWardly from the upper Wall 145 to the barriersupport 134. In one aspect of this embodiment, the upperWall 145 and the sideWalls 144 can be spaced apart from theembodiment of the invention.[0016] FIG. 4 is a partially schematic, partially cutaWayside elevation vieW of an apparatus in accordance Withanother embodiment of the invention.substrate 112 by relatively small distances (exaggerated inFIG.
3 for purposes of illustration) to keep the volume of theinternal air volume 160 relatively small. For example, theDETAILED DESCRIPTION OF THEINVENTIONupper Wall 145 can be separated from the upper surface 113of the substrate 112 by a distance of at least approximately[0017] The present invention is directed toWard methodsand apparatuses for distributing liquid over the surfaces ofone millimeter to approximately ten millimeters, or someother spacing.
The sideWalls 144 can be separated from anSep. 13, 2001US 2001/0020443 A1outer edge 115 of the substrate 112 by a distance of fromapproximately ?ve millimeters to approximately ten milli[0026]In a method in accordance With one embodiment ofis that it can reduce the time required to spin the internal airthe invention, the control arm 142 positions the barrier 140on the barrier support 134 and the substrate 112 and thebarrier 140 rotate together until the internal air volume 160volume 160 up to the same speed as the substrate 112.is spinning at approximately the same rate as the substrate[0022] The upper Wall 145 of the barrier 140 can includean aperture 141 aligned With a noZZle aperture 124 of aonto the upper surface 113 of the substrate 112, Where itmeters or some other distance.
An advantage of this featureliquid supply conduit 123 to alloW liquid to descend from thenoZZle aperture 124 to the upper surface 113 of the substrate112. The upper surface 145 can also include an engagementportion 147 for positioning the barrier 140. For example, theapparatus 110 can include a control arm 142 having apositioning head 143 for releasably engaging With theengagement portion 147 of the barrier 140. Once the positioning head 143 is engaged With the barrier 140, the control112. The liquid supply conduit 123 then disposes the liquid?oWs outWardly under centrifugal force toWard the edges ofthe substrate 112.
In one aspect of this embodiment, therotation speed of both the substrate 112 and the barrier 140can be up to 4,000 rpm, and in a further aspect of thisembodiment, the rotation speed can be in the range of fromapproximately 2,000 rpm to approximately 4,000 rpm orsome other rotational velocity.[0027] In an alternate method, the liquid supply conduitarm 142 can move the barrier 140 toWard and aWay from the123 can dispose the liquid on the substrate 112 before thebarrier support 134, for example during installation orsubstrate 112 spins up to an initial, relatively loW speedWithout the barrier 140 in place. The initial rotation speedremoval of the substrate 112 from the substrate support 133.In one aspect of this embodiment, the positioning head 143can be coupled to a vacuum source (not shoWn) to grip thecan be selected to be loWer than the loWest speed at Whichthe liquid forms non-uniformities With the adjacent air massbarrier 140 With a suction force and the control arm 142 can(for example, approximately 1,000 rpm).
The control armbe remotely actuated to move the barrier 140 toWard and142 can then loWer the barrier 140 into place on the spinningbarrier support 134 and release the barrier 140. The rotationrate of the substrate 112 and the barrier 140 can be graduallyaWay from the barrier support 134. In other embodiments,the control arm 142 and the positioning head 143 can haveother arrangements for positioning the barrier 140.[0023] The sideWalls 144 of the barrier 140 can be slopedto de?ne a frustum of a cone, or alternatively, the sideWalls144 can be vertical to de?ne a cylindrical section or havesome other con?guration. The sideWalls 144 can includeincreased to a higher rpm (for example up to 4,000 rpm),causing the liquid to spread out over the upper surface 113While at the same time spinning the internal air volume 160up to the same rotation rate of the substrate 112 and thebarrier 140.drain holes 146 adjacent to the barrier support 134 posi[0028] In still another method, gas can be selectivelytioned such that liquid ?oWing off the substrate 112 can ?oWthrough the drain holes 146 and through the spaces betWeenthe stanchions 135.
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