USP_6872254 (1063349), страница 2
Текст из файла (страница 2)
Furthermore, the drain 21and the exhaust port 22 may be coupled to a drain line 23aand an exhaust line 23b, respectively, Which must be securedto the boWl 20 With ?uid-tight rotating couplings. Still5560further, the boWl 20 is partially open so that it may be timeconsuming to bring the air mass adjacent to the substrate 12up to the same rotational speed as the substrate 12, particularly Where the substrate 12 rotates at high speed.FIG. 2 is a partially schematic, partially cutaWay sideelevation vieW of another conventional device 10a thatincludes a motor 30a coupled With a shaft 32a to a chucktoresist material that affect the uniformity of the layer33a. The chuck 33a includes a rectangular recess 36 forthickness. This problem can become more acute When thereceiving the rectangular substrate 12.
A cover 40 is releasably placed on the chuck 33a to rotate With the chuck 33avelocity of the substrate increases, for example, When thesubstrate is rotated at a high angular velocity and/or Whenand the substrate 12. The cover 40 includes an aperture 41the substrate has a large radius so that at even moderate 65 that alloWs ?uid to pass from the ?uid supply conduit 23 toangular velocities, the linear speed toWard the edge of thesubstrate is high.the surface of the substrate 12.
The apparatus 10a can furtherinclude a collection vessel 20a ?xed relative to the motorUS 6,872,254 B23430a and having a drain 21 and an exhaust port 22 for3 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.FIG.
3 is a partially schematic, partially cutaWay sideremoving liquid and gas from the region adjacent to thesubstrate 12.One problem With the device 10a shoWn in FIG. 2 is thatthe liquid disposed on the substrate 12 can become trappedbetWeen 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 Withround substrates, particularly Where the diameter of theelevation vieW of an apparatus 110 that spins a substrate 11210and 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 agenerally 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 theit can be adequately supported by the apparatus 110 and solong 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 sub20strate at a ?rst rate. The microelectronic substrate can havea ?rst surface that receives the liquid and a second surfacefacing opposite the ?rst surface With the engaging portioncon?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 ?rst25portion of gas adjacent the microelectronic substrate androtating With the microelectronic substrate from a secondportion of gas spaced apart from the microelectronic substrate and generally stationary relative to the microelectronicsubstrate.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 approximately303540The 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.45embodiment of the invention.50circular 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 barrier112. The barrier 140 can also include sideWalls 144 extendsubstrate 112 by relatively small distances (exaggerated in55FIG. 4 is a partially schematic, partially cutaWay sideThe 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.barrier 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 generallying 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 approximatelyelevation vieW of an apparatus in accordance With anotherembodiment of the invention.DETAILED DESCRIPTION OF THEINVENTIONsubstrate 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 barriergenerally parallel to the upper surface 113 of the substrateart.elevation vieW of an apparatus in accordance With anThe support assembly 131 can further include a barriersupport 134 to spin at the same rate as the substrate 112.
Thebarrier 140 can include an upper Wall 145 facing andFIG. 1 is a partially schematic, partially cutaWay sideelevation vieW of an apparatus in accordance With the priorFIG. 2 is a partially schematic, partially cutaWay sideelevation vieW of another apparatus in accordance With theprior art.FIG. 3 is a partially schematic, partially cutaWay sidehang the substrate support 133.140 relative to the barrier support 134.
Alternatively, thefrom about 7,000 Angstroms to about 10,000 Angstroms.BRIEF DESCRIPTION OF THE DRAWINGSThe 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 oversupport 134 that extends radially outWardly beyond the3,000 Angstroms greater than the ?rst value by positioninga 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, orThe 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.one millimeter to approximately ten millimeters, or some60other 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 air65volume 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 liquidUS 6,872,254 B256supply conduit 123 to allow liquid to descend from thenozzle aperture 124 to the upper surface 113 of the substraterotation speed can be in the range of from approximately2,000 rpm to approximately 4,000 rpm or some other112. The upper surface 145 can also include an engagementrotational velocity.portion 147 for positioning the barrier 140.
For example, theIn 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 (forapparatus 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 controlarm 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 the10barrier 140 With a suction force and the control arm 142 canbe remotely actuated to move the barrier 140 toWard andaWay from the barrier support 134. In other embodiments,increased to a higher rpm (for example up to 4,000 rpm),15the control arm 142 and the positioning head 143 can haveother 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 some20other con?guration.
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