USP_6576055 (1063346), страница 2
Текст из файла (страница 2)
2 is thatthe liquid disposed on the substrate 12 can become trappedUS 6,576,055 B243between the loWer surface of the substrate 12 and the Wallsof the recess 36 into Which the substrate 12 is placed. Afurther drawback is that the recess 36 is siZed for rectangularsubstrates 12, making it unsuitable for or unusable WithFIG. 3 is a partially schematic, partially cutaWay sideelevation vieW of an apparatus 110 that spins a substrate 112and a barrier 140 at approximately the same rate to distributea liquid over the substrate 112 in accordance With anembodiment of the invention. The substrate 112 can have around substrates, particularly Where the diameter of thegenerally round planform shape and a diameter of at leastapproximately eight inches.
For example, in oneround substrate exceeds the Width of the recess 36.SUMMARY OF THE INVENTIONembodiment, the substrate 112 can have a diameter ofThe present invention is directed toWard methods andapparatuses for uniformly distributing a liquid over a surfaceof a spinning microelectronic substrate. An apparatus insubstrate 112 can have other diameters and shapes so long asapproximately tWelve inches and in other embodiments the10long as the liquid can be distributed on the substrate 112 inaccordance With one aspect of the invention can include aa uniform manner.support having an engaging portion for engaging the microelectronic substrate and rotating the microelectronic substrate at a ?rst rate.
The microelectronic substrate can have15a ?rst surface that receives the liquid and a second surfacecon?gured to engage less than the entire second surface. Arotating barrier proximate to the support rotates at a secondrate approximately equal to the ?rst rate to separate a ?rstportion of gas adjacent the microelectronic substrate androtating With the microelectronic substrate from a secondsubstrate.In a method in accordance With an aspect of the invention,a liquid having a single viscosity can be distributed over the?rst surface of the substrate to a generally uniform thicknessranging from a ?rst value to a second value approximately3,000 Angstroms greater than the ?rst value by positioninghang the substrate support 133.25BRIEF DESCRIPTION OF THE DRAWINGSThe support assembly 131 can further include a barriersupport 134 that extends radially outWardly beyond the30substrate support 133 and the substrate 112 to support androtate the barrier 140 as the support assembly 131 rotates.The barrier support 134 can include a plurality of spacedapart stanchions 135 to restrict radial motion of the barrier35barrier 140 can rotate independently of the substrate 112, asWill be discussed in greater detail beloW With reference toFIG.
4.In one embodiment, the barrier 140 has a generally40circular 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 barrier140 relative to the barrier support 134. Alternatively, thea barrier to separate a rotating ?rst volume of gas adjacentthe ?rst surface from a generally stationary second volumeof gas.
For example, the 3,000 Angstrom range can extendfrom about 5,000 Angstroms to about 8,000 Angstroms, orfrom about 7,000 Angstroms to about 10,000 Angstroms.The viscosity can be selected to be from about six centipoiseto about tWenty centipoise and the liquid can be distributedto a thickness that varies by less than tWenty Angstroms.The apparatus 110 can include a motor 130 coupled Witha 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 overfacing opposite the ?rst surface With the engaging portionportion of gas spaced apart from the microelectronic substrate and generally stationary relative to the microelectronicit can be adequately supported by the apparatus 110 and soFIG. 1 is a partially schematic, partially cutaWay sidesupport 134 to spin at the same rate as the substrate 112. Thebarrier 140 can include an upper Wall 145 facing andelevation vieW of an apparatus in accordance With the priorgenerally parallel to the upper surface 113 of the substrate112. The barrier 140 can also include sideWalls 144 extendart.FIG.
2 is a partially schematic, partially cutaWay side45elevation vieW of another apparatus in accordance With theprior art.FIG. 3 is a partially schematic, partially cutaWay sideelevation vieW of an apparatus in accordance With anembodiment of the invention.substrate 112 by relatively small distances (exaggerated in50FIG. 4 is a partially schematic, partially cutaWay sideelevation vieW of an apparatus in accordance With anotherembodiment of the invention.DETAILED DESCRIPTION OF THEINVENTIONThe present invention is directed toWard methods andapparatuses for distributing liquid over the surfaces ofmicroelectronic 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.ing 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 theFIG.
3 for purposes of illustration) to keep the volume of theinternal air volume 160 relatively small. For example, theupper Wall 145 can be separated from the upper surface 113of the substrate 112 by a distance of at least approximatelyone millimeter to approximately ten millimeters, or some55other spacing.
The sideWalls 144 can be separated from anouter edge 115 of the substrate 112 by a distance of fromapproximately ?ve millimeters to approximately ten millimeters or some other distance. An advantage of this featureis that it can reduce the time required to spin the internal air60volume 160 up to the same speed as the substrate 112.The upper Wall 145 of the barrier 140 can include anaperture 141 aligned With a noZZle aperture 124 of a liquidsupply 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 engagement65portion 147 for positioning the barrier 140. For example, theapparatus 110 can include a control arm 142 having apositioning head 143 for releasably engaging With theUS 6,576,055 B256engagement portion 147 of the barrier 140.
Once the positioning head 143 is engaged With the barrier 140, the control112 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 (forexample, approximately 1,000 rpm). The control arm 142arm 142 can move the barrier 140 toWard and aWay from thebarrier support 134, for example during installation orremoval 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 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 graduallybarrier 140 With a suction force and the control arm 142 canincreased to a higher rpm (for example up to 4,000 rpm),be remotely actuated to move the barrier 140 toWard andaWay from the barrier support 134.
In other embodiments,10the control arm 142 and the positioning head 143 can haveup to the same rotation rate of the substrate 112 and theother arrangements for positioning the barrier 140.The sideWalls 144 of the barrier 140 can be sloped tode?ne a frustum of a cone, or alternatively, the sideWalls 144can be vertical to de?ne a cylindrical section or have some 15other con?guration. The sideWalls 144 can include drainholes 146 adjacent to the barrier support 134 positioned suchthat liquid ?oWing off the substrate 112 can ?oW through thedrain holes 146 and through the spaces betWeen the stanchions 135. In other embodiments, the barrier 140 can havevolume 160 and the external air volume 150.
For example,gas can pass out of the internal air volume 160 through thedrain holes 146 and into the internal air volume 160 throughthe vents 148. Alternatively, the barrier 140 can be periodically lifted from the barrier support to alloW gas to escapefrom Within the barrier 140.In any of the methods discussed above With reference toFIG.
3, rotating the internal air volume 160 can reduce thelikelihood for the liquid to form Waves or other nonshoWn) that includes a photoresist material for etching thesubstrate 112 generally as discussed above. Alternatively,uniformities on the upper surface 113 of the substrate 112,particularly toWard the outer edge of the substrate 112.the liquid supply conduit 123 can be coupled to sources ofother liquids.The apparatus 10 can further include a collection vessel 35the collection vessel 120 can collect liquid that spills overthe edge 115 of the substrate 112 as the substrate 112 spins.A seal 127 betWeen the drive shaft 132 and the base 126prevents the liquid collected in the collection vessel 120from leaking around the drive shaft 132. A drain 121 beloWthe base 126 conducts the collected liquid aWay from thecan have vents 148 (in addition to the drain holes 146) thatalloW some ?uid communication betWeen the internal airother shapes and con?gurations that separate the external airextending upWardly around the substrate 112.
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