APPARATUS FOR DOUBLE FLOATING WAFER TRANSPORT AND PROCESSING

Abstract: Apparatus (10) with in its tunnel passageway (12) transport and processing under double floating condition takes place of wafers (14) and whereby by means of medium flows (16) simultaneously a spinning of these wafers (14) is accomplished.

Description: Improved apparatus for double floating wafer transport and processin The invention relates to an improved apparatus for double floatin transport and processing of ωafers. In for instance the Dutch Patent Applications No's 8 103 979 and 8300649 of applicant systems are described for double floating trans- port and processing of wafers, whereby in the tunnel passageway during processing the ωafer with a linear displacement thereof does not inten¬ tionally rotate. Hoωever, with some processings it is desirable, that temporary su ωafer rotation takes place. The present invention satisfactory solves the problem, whereby during such processing a rotation of the wafer is accomplished by means of floωs of fluid, ωhich, discharged from the supply manifolds, strike the ωafεr in direction of ωafer rotation and subsequently are carried off through discharge manifolds. Thereby by increasing the passage height it is possible to attain a very large number of revolutions per minute. Furthermore, it is often desirable, that the uafer at least tempo¬ rary, for instance one second, has a negligible displacement in linear direction. To meet such requirement, a following positive feature of the appa ratus is, that as seen in dirsction of linear displacement of the uafer, in the central section of rotation a lower pressure is maintained than in the adjacent tunnel sections. With for instance cleaning and rinsing of the ω- * far it is advisabl that a large number of high intensity flows of liquid strike the wafer surface. Thereby such medium must be removed as fast as possible. To enable this, a following positive feature is, that as seen in direction of linear displacement of the wafer, in the tunnel sidewalls only a restricted number of groups of supply manifolds are positioned, however extending over at least the width of the uafer. As a result, the size of these channels can be considerably larger A following very positive feature is, that the rotation cannot on¬ ly be accomplished by means of flows of liquid, but also by means of floω of gaseous medium. Thereby an improved processing can take place, ωith a complete change of medium, if required. Furthermore, the apparatus can be structured such, that this wafer rotation can be maintained during a subsequent displacement of this wafer Thereby another positive feature is, that these flows, accomplishi i _ the ωafβr rotation, cooperate ωith floωs of medium, e.~tablishing the linear uafer displacement. Furthermore, it is of importance, that as the supply pressure is maximal in that tunnel section, also the discharge of medium is maximal, enabling the pressure in this tunnel section to remain ωithin alloωable parameters. In addition, it is desirous, that as the floωs of liquid result in a surface tension of the tunnel sidewalls, such tension is as small as possible. For that reason another positive feature is, that the tunnel height in the process section is at least locally considerably larger than is required for a double floating wafer transport with a minimum consumption of transport medium. The required locally increased pressure in the tunnel passageway may not affect the double floating wafer transport in that tunnel, as for instance in the pressure adaption modules towards or from vacuum modules. Therefore another positive feature is, that in the tunnel displacea- ble valve plates are incorporated, which during such processing seal off the adjacent tunnel sections from the processing section. Furthermore, the spinning velocity can be very high, for instance 10 000 rpm, as could be required for an improved processing, such as the fast removal of liquid remnants from the wafer surf c3. The spin system is also very suitable to apply a coating on a wafer, whereby in particular the considerable acceleration and de-acceleration of the uafer are important. Furthermore, any material for the process section, such as for in¬ stance teflon for a dopant cαater, can be used. Furthermore, in the process area of the process section discharge manifolds may not be positioned, uith almost entirely a discharge of the medium, supplied through the upper tunnel uall, through discharge manifolds, positioned in the lower tunnel uall. Furthermore, the process system can be adapted to any type of wet processing and such including wet cleaning by,means of ultrasonic or mega- sonic energy and etching thereuith. The foregoing and other objects, features and advantages of the in¬ vention will be more apparant from the following more particular descrip¬ tion, as illustrated in the accompanying drawings: Figure 1 schematically shoωs the principle of double floating ωafer spinning in the tunnel paβsageωay of the apparatus according to the inven¬ tion. Figure 2 schematically shows the principle of double floating wafer spinning combined ωith a linear ωafer displacement in the tunnel passage- way. Figure 3 is a detailed sectional view of the tunnel in the area of supply and discharge manifolds for spinning. Figure -4 is a detailed sectional view of a modified tunnel ωith spinning supply and discharge manifolds on one side of the ωafer and dis- charge manifolds for a linear ωafer displacement on the other side. Figure 5 shoωs a tunnel section, ωherein different groups of medium floωs strike the wafer. Figure 6 is a cross-sectional view over line 6-5 of the tunnel sec¬ tion according to Figure 5. Figure 7 is a cross sectional view over line 7-7 of the tunnel sec¬ tion according to Figure 5. Figure 8 shoωs a coating apply section of a modified apparatus. In Figure 1 apparatus 10 is shoωn. Thereby in tunnel 12 transport and processing of ωafers 14 take place under double floating condition. By means of medium floωs 16 a spinning of this ωafer is accomplished, because the resulting forces of these floωs provide a spinning moment. During such spinning the wafer 14 is kept on its place because a maximal discharge takes place through the discharge manifolds 16. Such discharge is larger than that through the manifolds 20, which are positio- ned aside this spin centre. During the spin processing the then closed valve plates seal off the proces section 26 from the adjacent tunnel sections 26 and 30, if required. Such temporary sealing-pff can also be accomplished by means of an established gas lock, including an intensified supply of gaseous medium and a increased discharge capacity in such lock. Thereby such supply and discharge taking place through a large number of channels, arranged on both sides of the tunnel passageway and extending in lateral direction of this tunnel. In Figure 2 the spin medium 16 cooperates with medium flous 32, enabling a combined spinning and linear displacement of the wafer. In Figure 3 on both sides of the tunnel 12 the supply manifolds 34 and 36 together with the respective discharge manifolds 38 and 40 extend into passage 42. Flous of medium 15, urged through these maniflolds 34 and 36, strike the ωafer 14, move along the wafer surface and are subse¬ quently discharged through the discharge manifolds 38 and 40. In Figure 4 by means of floωs 16, in loωer gap 45 striking the bot¬ tom side of the ωafer 14, a spinning thereof is established, ωhereas in the upper gap 48 processing of this wafer takes place. Such processing might be any type of wet processing, including cleaning and etching by means of ultrasonic or msgasonic energy and the applying of coating, whe¬ reby the spinner can have a considerable radial velocity, for instance 10 000 rpm and temporary no or a negligible rotation. Thereby in the upper gap 4B the dc-uble floating condition might be maintained by means of gaseous medium 50. Such medium might also be used for the linear displacement of the ωafer. Uithin the scope of the invention such wet processing includes the processing on both sides of the ωafer. In Figure 5 the tunnel section 52 is sho-.-n, whereby over a conside¬ rable length both linear displacement and rotation of the wafer is esta¬ blished. Such by means of numerous flows 15 and 32. Thereby these flows can strike the wafer in any direction, as is indicated in Figures 6 and 7, and can be a combination of gaseous and fluid medium. As a rεεult, by means of these flows a highly effective, two sided wet cleaning or etching of the wafer is mads possible, because each sur¬ face segment of the wafer is hit for many times by these flows and such under various angles, Furthermore it is possible, that in the upper gap 48 coating of the wafer takes place by means of madium in liquid phase, whereas on the other side for instance the spinning under floating condition is accomplished by means of a thinner of such coating, whether or not in combination with gaseous medium. In Figure 8 the coating station of the apparatus 10 is shown. There¬ by by means of cooperating floωs of medium 16 and other, not indicated media the wafer is temporary kept in the coating apply section. Through channel 54 photoresist is applied on the wafer, whereby by means of the flows 16 during a short period of time a relatively low radial velocity of for instance 400 rpm is maintained for the ωafer. Thereafter the wafer rotation is accelerated to for instance 5 000 rpm and is maintained for for instance 8 seconds. As a result, the coating is evenly spread over the wafer surface and whereby excessive coating is released from the sides of the wafer. Thereafter the radial velocity is further increased to for instance 7 000 rpm and whereby by means of a whether or not increased supply of nitrogen through manifolds 56 a drying of the applied coating takes place. The discharge of this medium occurs for at least part thereof through dis- charge manifolds 58, positioned on the bottom side of the tunnel. Because of the restricted discharge capacity the upper gap 48' can have a relatively large height, which prevents a coverage of the upper sidewall of the tunnel passageway with coating. ύ/ithiπ the scope of the invention other structures of the tunnel are possible and can, whether or not temporary, variations in the flows of the media, as for instance by means of the ultrasonic or megasonic energy, be used. Furthermore, such spin, processing can include the use of a spin table, having a smaller size than the wafer to be processed and which table is part of the double floating transport system. Thereby such wafer might temporary rest on this table. Furthermore, any type of material, such as stainless steel, quarz, plexiglass and teflon are possible, for the tunnel structure or part thereof, It is possible, that ωith correctly measured supplies and discharges of thε different media in relation ωith the successive process stadia, unalloωable pressure differences in the tunnel passageway, affecting the transport and processing of the ωafers, cannot take place. As a result, there ωill be no need for the use of the valve plates 22 and 24, ωhich helps in the control on contamination in the tunnel passageωay. For instance, during the spin processing the discharge capacity in the process section is maximal, ωith an established pressure in the rela¬ ted tunnel area, ωhich can even be lower than that in the adjacent tunnel sections, As the wafers displace in the transport sections of this tunnel, then a change in ωafer velocity as the result of differences in pressure in the spin process section and observed by sensors ωill immediately result in providing signals from these sensors towards control systems for immediate corrections in the supply and discharge of these sections. Thereby the distance betueen successive uafers can be that large, that differences in wafer velocity are allowable.

Claims: C L A I Pl S 1 , Apparatus, comprising: a tunnel with a passageuay for double floating transport and processing of wafers; channels, positioned in the upper and louer ωall of said tunnel for supply of medium towards said tunnel passageway and for dis¬ charge of said medium from said passageway; and a spin-process tunnel section including such means, that at least during one processing said wafer rotates under double floating condition and at least during non-processing said wafer displaces in linear direction under double floating condition. 2, Method of the apparatus according to Claim 1, wherein in said spin process section of said tunnel at least one group of high pressure medium jets, supplied into said tunnel passageway, at least during said spin processing provide a rotation of said wafer under double floating condition together with the processing action. 3, Method according to Claim 2, wherein at least in said spin pro¬ cess section of said tunnel by means of additional flows of fluid medium, supplied into said passageway, at least during the presence of a wafer in said section a double floating condition for said uafer is maintained, 4, Method according to Claim 3, wherein at least in said spin pro¬ cess section of said tunnel by means of supplied flous of fluid medium temporary and at least during non-spinprocessing a linear displacement of said wafer in longitudinal direction of said tunnel under double floating condition is established, 5, fϊethod according to Claim 3, wherein during said spin processing by mean-* of flows of fluid medium, supplied during the spin processing, striking the wafer and subsequently discharged, an almost stationary po¬ sition of said slightly oscilating wafer is maintained in both lateral and longitudinal direction of said tunnel, 6, Method according to Claim 5, wherein in said spin process section simultaneously floωs of fluid medium, providing said uafer rotation, are directed touards both sides of said wafer and as seen in both lateral and longitudinal direction of said tunnel, in at least almost the same area of said tunnel section. 7, Method according to Claim 5, wherein in said spin process section of said tunnel flows 'of fluid medium, locally providing said uafer rotation, only strike one side of said uafer and touards the other side of said uafer floωs of fluid medium are directed, ωhich at least maintain a double floating condition, 8, Apparatus, incorporating the method according to Claim 5, ωherei in at least one of the sideωalls of said tunnel channels are positioned, ωhich are positioned in relation to said tunnel passageωay in that ωay, that floωs of medium, urged through said channels, provide a rotation moment for said wafer. 9. Apparatus incorporating the method according to Claim 5, wherein it contains such means, that in the spin process area of the tunnel pas¬ sageway the wafer at least temporary is not considerably displaced in longitudinal direction of said tunnel, 10, Apparatus according to Claim 9, ωherein for that purpose in at least one of the tunnel sideualls groups of supply and discharge channels are positioned, which as seen in longitudinal direction of said tunnel, temporary provide opposite flows towards said uafer, 11, Apparatus according to Claim 10, uherein said groups of channels, as seen in longitudinal direction of said tunnel, are arranged aside said channels, providing the flous of fluid medium for wafer rotation. 12, Apparatus according to Claim 11, uherein in at least one of said tunnel sideωalls groups of channels are located, uhich are arranged in relation to said tunnel passageuay in that ωay, that medium flous, urged through said channels, have at least a de-accaleration effect on the rotation of said uafer, 13, Apparatus according to Claim 12, wherein said channels are arran¬ ged in that ωay, that the medium flows, urged from said channels, esta- blish an opposite uafer rotation, 14, Method of the apparatus according to Claim 5, ωherein said me¬ dium is a liquid to be used for spin processing, 15, Apparatus according to Claim 13, uherein in at least one of said tunnel sideualls groups of channels are arranged under an inclined posi¬ tion in relation to said tunnel uall for supplying flous of gaseous medium to accomplish and maintain said ωafer rotation* 16* Apparatus, incorporating the method according to Claim 5, uherein in at least one of said tunnel sideωalls, as seen in longitudinal direc- tion of said tunnel, aside groups of channels for feeding fluid medium touards said tunnel passageωay and discharging said fluid medium from said passageuay multiple groups of inclined positioned channels, extending in lateral direction of said passageuay are arranged for feeding gaseous medium towards said tunnel passageuay and along said uafer towards common discharge channels to provide a gas lock, 17. Apparatus according to Claim 15, comprising means to increase the ωafer rpm to such extent, that medium in liquid form can at least partly be removed from said wafer surface, 13. Method of said apparatus according to Claim 17, whereby said wafer rotation exceeds 5 000 rpm, 19, Method according to Claim 5, '.herein a difference in pressure in said spin process section almost instantly results in a pressure adap¬ tion in at least the adjacent tunnel sections to such extent, that diffe- rencev in speed in longitudinal direction of said wafer remains within allowable values, 20, Apparatus incorporating the method according to Cl3im 19, where¬ in means are used to control said double floating wafer transport and processing, 21, Apparatus according to Claim 20, wherein use is made of sensors, cooperating with wafers passing through and providing control signals towards flow regulating means, 22, Apparatus according to Claim 21 , uherein in said tunnel passage¬ uay the minimum distance between successive wafers is that large, that said wafers cannot make contact with each other, 23, Method according co Claim 19, ωhsrair. the pressure in said transport sections of said tuππsl is above atmospheric pressure, 24, Method according to Claim 23, ■ •/herein during the spin processing the pressure in said tunnel passageway at the centre of said processing is lower than in the tunnel sections adjacent to said centre and the length of said centre, as seen in longitudinal direction of said tunnel, has at least the size of said uaf * :r, 25, Apparatus according to Claim 15, u erein the height.of said tunnel at the centre of said spin processing is considerably larger than the height of the adjacent transport sections of said tunnel, 26, Apparatus according to Claim 25, wherein it is structured in that ωay, that in said spin process section coating can be applied on at least one side of said ωafer, 27, Apparatus according to Claim 26, wherein at the processing side the discharge capacity is smaller than at the non-processing side, 23, Apparatus according to Claim 27, uherein in said spin process section the aall at the processing side does not contain discharge channels and said wall, as seen in longitudinal direction of said tunnel, has a length, which is larger than the size of said wafer, 29, Apparatus according to Claim 2B, wherein stations for applying of coating are used, which are similar to those as used in existing spinners. 30. Apparatus according to Claim 29, wherein in the lower uall of said spin section a spin table is located, having a diameter, ωhich is smaller than said ωafer to be processed and containing supply grooves and discharge channels for at least a double floating ωafer transport towards and from its centre, 31. Method of the Apparatus according to Claim 30, wherein during a processing step said ωafer at least temporary is suctioned against said table. 32. Apparatus according to Claim 1, ωherεin it is structured that ωay, that it is applicable for any type of cleaning, rinsing, drying, stripping and etching of ωafers or to apply dopant or developing fluid on said ωafers and such whether or not by means of ultrasonic or megssonic energy. 33. Method of the apparatus according to Claim 32, ωherein at least temporary said uafer does not rotate. 34. Apparatus according to Claim 32, ωherein in successive tunnel sections the structure is such, that processing takes place under double floating condition of said ωafers.

Inventors: BOK EDWARD, BOK, EDWARD
Applicants: BOK EDWARD, BOK, EDWARD
Application year: 1985
Main classification: H05K13
IPC codes: B65G51, H01L21