Apparatus for processing a wafer-shaped article

Abstract

Apparatus for processing a wafer-shaped article, the apparatus comprising a support configured to support the wafer-shaped article during a processing operation; wherein: the support comprises a support body and a plurality of gripping pin assemblies adapted and positioned relative to the support body for gripping the wafer-shaped article, wherein each of the gripping pin assemblies is rotatable relative to the support body between a gripping configuration in which the gripping pin assemblies grip the wafer-shaped article, and a non-gripping configuration in which the gripping pin assemblies do not grip the wafer-shaped article; each of the gripping pin assemblies protrudes from a respective hole in the support body; and a sealing member is positioned between at least one of the gripping pin assemblies and the respective hole, the sealing member being configured to restrict infiltration of a processing liquid used in the processing operation into the hole.

Claims

1. An apparatus for processing a wafer-shaped article, the apparatus comprising a support configured to support the wafer-shaped article during a processing operation to be performed on the wafer-shaped article; wherein: the support comprises a support body and a plurality of gripping pin assemblies adapted and positioned relative to the support body for gripping the wafer-shaped article, wherein each of the gripping pin assemblies is rotatable relative to the support body between a gripping configuration in which the plurality of gripping pin assemblies grip the wafer-shaped article, and a non-gripping configuration in which the plurality of gripping pin assemblies do not grip the wafer-shaped article; each of the plurality of gripping pin assemblies protrudes from a respective hole in the support body; a sealing member is positioned between at least one of the plurality of gripping pin assemblies and the respective hole, the sealing member being configured to restrict infiltration of a processing liquid used in the processing operation into the hole; the sealing member comprises an inner sealing body, and an outer layer that reduces a sticking force between the sealing member and the hole, or the sticking force between the sealing member and the at least one of the plurality of gripping pin assemblies; and each of the at least one of the plurality of gripping pin assemblies comprises a body, a first circumferential groove formed in and extending around the body in which the sealing member is seated around a circumference of the body, and a second circumferential groove formed in and extending around the body.

2. The apparatus according to claim 1, wherein the sealing member comprises an O-ring.

3. The apparatus according to claim 1, wherein the sealing member comprises a perfluoroelastomer polymer.

4. The apparatus according to claim 1, wherein the sealing member is configured to rotate with the at least one of the plurality of gripping pin assemblies relative to the hole.

5. The apparatus according to claim 1, wherein the outer layer is a fluoropolymer (e.g. PTFE) based outer layer, different than material of the inner sealing body.

6. The apparatus according to claim 1, wherein each of the plurality of gripping pin assemblies has a first gear that is located inside the support body, and the support body includes a driving mechanism for driving rotation of the first gear so as to rotate that gripping pin assembly.

7. The apparatus according to claim 6, wherein the driving mechanism comprises a second gear that is meshed with each of the first gears, so that rotation of the second gear causes synchronised rotation of each of the first gears.

8. The apparatus according to claim 1, wherein the support body comprises a respective channel for outputting a flow of a gas from the second circumferential groove.

9. The apparatus according to claim 1, wherein each of the gripping pin assemblies comprises: a first gear; and a gripping part at a second end of the body for gripping the wafer-shaped article.

10. The apparatus according to claim 9, wherein the gripping part comprises a longitudinal protrusion from the second end of the body, the longitudinal protrusion being spaced apart from a longitudinal axis of the at least one of the plurality of gripping pin assemblies.

11. The apparatus according to claim 1, wherein each of the plurality of gripping pin assemblies comprises a reinforcement member positioned in a recess formed in that gripping pin assembly.

12. The apparatus according to claim 1, wherein the support is a chuck surrounded by a process chamber for processing of semiconductor wafers.

13. The apparatus according to claim 1, wherein the gripping pin assemblies are positioned in a circular series surrounding an area where the wafer-shaped article is to be positioned on the support, and the gripping pin assemblies are configured to make edge contact with the wafer-shaped article thereby to constrain it from lateral movement away from a pre-determined position.

14. A gripping pin assembly for use in an apparatus for processing a wafer-shaped article, the gripping pin assembly comprising: a body; a gear; a first circumferential groove formed in and extending around the body for seating a sealing member around the circumference of the body; and a second circumferential groove formed in and extending around the body.

15. A gripping pin assembly for use in an apparatus for processing a wafer-shaped article, the gripping pin assembly comprising: a body; a gear; a first circumferential groove formed in and extending around the body; a second circumferential groove formed in and extending around the body; and a sealing member seated in the first circumferential groove.

16. The gripping pin assembly according to claim 14, wherein the gripping pin assembly further comprises a reinforcement member positioned in a recess formed in the body.

17. The gripping pin assembly according to claim 16, wherein the reinforcement member extends from a first end of the body to a point at or beyond the first circumferential groove.

18. The gripping pin assembly according to claim 14, wherein the gripping pin assembly comprises a protrusion that protrudes longitudinally from a second end of the body, the protrusion being spaced apart from a longitudinal axis of the gripping pin assembly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the present invention will now be discussed, by way of example only, with reference to the accompanying Figures, in which:

(2) FIG. 1 is a sectional view of a chuck for an apparatus for processing semiconductor wafers according to an embodiment of the present invention;

(3) FIG. 2 is a perspective view of the chuck of FIG. 1;

(4) FIG. 3A is a sectional view of a pin assembly according to an embodiment of the present invention, for use in the chuck of FIGS. 1 and 2;

(5) FIG. 3B is a plan view of the pin assembly of FIG. 3A; and

(6) FIG. 3C is a perspective view of the pin assembly of FIG. 3A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS AND FURTHER OPTIONAL FEATURES OF THE INVENTION

(7) FIG. 1 is a partial sectional view of a chuck 1 for an apparatus for processing semiconductor wafers according to an embodiment of the present invention.

(8) In use, the chuck 1 may be surrounded, or partially surrounded, by a process chamber for single wafer wet processing of semiconductor wafers. The process chamber can have any suitable configuration.

(9) As shown in FIG. 1, the chuck 1 comprises a chuck body 3 that comprises a generally cup-shaped base part 5, a spindle receiving part 7 surrounded by the cup-shaped base part 5, and an upper part 9.

(10) The chuck 1 is intended to be mounted on a spindle by the spindle being inserted into a recess 11 formed in the spindle receiving part 7. The recess 11 is shaped to operatively engage with the spindle by having a shape that corresponds to the shape of the spindle. In this embodiment, the recess 11 has a frustoconical shape that corresponds to a complementary frustoconical shaped spindle.

(11) Of course, in other embodiments the construction of the chuck may be different to that described above. For example, the chuck may instead be formed as a single piece, or from fewer or more components than those illustrated in FIG. 1.

(12) The chuck 1 can therefore be rotated relative to the process chamber using the spindle. The chuck 1 may therefore be referred to as a spin chuck.

(13) The upper part 9 and the base part 5 are fixed together, for example using screws.

(14) The upper part 9 has an upper surface 13 for supporting a semiconductor wafer. In particular, the upper surface 13 is for contacting a lower surface of a semiconductor wafer, so as to support the semiconductor wafer from beneath.

(15) As shown in FIG. 1, the upper part 9 of the chuck body 3 encloses a gas distribution chamber 15. The gas distribution chamber 15 is adjacent to a top end of the recess 11 in the spindle receiving part 7, such that when a suitably shaped spindle is received into the recess 11, a top end of the spindle extends into the gas distribution chamber 15 in the upper part 9.

(16) The spindle is preferably hollow and includes a plurality of radially directed through-holes at its distal end. Thus, pressurised gas, such as Nitrogen gas, delivered through the hollow spindle may be directed through these through-holes into the gas distribution chamber 15.

(17) The upper part 9 of the chuck body 3 further includes an annularly arranged plurality of holes 17 extending from the gas distribution chamber 15 to the upper surface 13 of the upper part 9. Accordingly, gas may be delivered through the hollow spindle, the gas distribution chamber 15 and the holes 17 such that a wafer, when present, may be floated on a gas cushion during processing. Such gas may also be used to aid in securing a wafer to the chuck 1 operating on the Bernoulli principle.

(18) However, the supply of gas to the upper surface 13 is not essential, and therefore may be omitted in other embodiments. For example, it is not essential for the chuck to include the gas distribution chamber 15 and holes 17, and in other embodiments the gas distribution chamber 15 and holes 17 may be omitted.

(19) As shown in FIGS. 1 and 2, the chuck 3 further includes a plurality of pin assemblies 19. As shown in FIG. 2, the plurality of pin assemblies 19 are positioned in a circular series surrounding an area where a wafer-shaped article is to be positioned on the upper surface 13 of the upper part 9.

(20) As shown in FIG. 1, each of the pin assemblies 19 is partly (mostly) positioned in a respective hole 21 in the upper part 9 of the chuck body 3. Specifically, each of the pin assemblies 19 is received in a respective hole 21 in the upper part 9 of the chuck body 3 with a part of the pin assembly 19 protruding out of the hole 21 beyond the upper surface 13 of the upper part 9.

(21) In this embodiment, the holes 21 are cylindrical holes that are bored into the upper part 9 of the chuck body 3.

(22) The configuration of the pin assemblies 19 in an embodiment of the present invention is illustrated in FIGS. 3A to 3C.

(23) As shown in FIG. 3A, each of the pin assemblies 19 comprises a main body part 22 that is substantially cylindrical in shape, a gear 23 provided at a first end of the main body part 22, and a longitudinal protrusion 25 provided at a second end of the main body part.

(24) The gear 23 comprises a plurality of gear teeth 27 that extend radially outwards from the first end of the main body part 22.

(25) In this embodiment, the gear 23 is integrally formed with the main body part 22. In other words, the gear 23 is formed as one piece with the main body part 22, from the same material as the main body part 22. However, in other embodiments the gear 23 may be formed separately to the main body part 22 and then attached to the main body part 22, and may be formed of a different material to the main body part 22.

(26) The longitudinal protrusion 25 is integrally formed with the main body part 22. In other words, the longitudinal protrusion 25 is formed as one piece with the main body part 22, from the same material. However, in other embodiments the longitudinal protrusion 25 may be formed separately to the main body part 22 and then attached to the main body part 22, and may be formed of a different material to the main body part 22.

(27) The main body part 22 (and optionally also the longitudinal protrusion and/or the gear) of the pin assemblies 19 may be made from a plastic such as polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA), polyphenylenesulfide (PPS), polyetheretherketone (PEEK), polystyrene/polyethylstyrene (PS/PES), ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), homopolymer of chlorotrifluoroethylene (PCTFE), fluorinated ethylene propylene (FEP), or ethylene chlorotrifluoroethylene (ECTFE).

(28) The longitudinal protrusion 25 in this embodiment is cylindrical in shape. However, this is not essential.

(29) The longitudinal protrusion 25 extends longitudinally from a top surface 29 of the main body 22. This top surface 29 is substantially flat, apart from the longitudinal protrusion 25.

(30) The longitudinal protrusion 25 is narrower (has a smaller diameter) than the main body 22 and is positioned off-centre relative to the main body 22. The longitudinal protrusion 25 is therefore spaced apart from a longitudinal axis of the main body 22. In other words, the longitudinal protrusion 25 is an eccentric protrusion.

(31) As shown in FIG. 3A, a recess 31 is formed in a bottom surface of the main body 22. For example, the recess 31 may be a bore that is drilled into the bottom surface of the main body 22, or otherwise formed in the bottom surface of the main body 22.

(32) An insert 33 is positioned in the recess 31. For example, the insert 33 may be inserted into the recess 31 from the bottom surface of the main body 22.

(33) The insert 33 has a higher strength and/or Young's modulus than the main body 22. The insert 33 therefore acts as a reinforcement member that increases the strength and/or stiffness of the main body 22.

(34) The insert 33 may be made of metal, for example titanium.

(35) As shown in FIGS. 1 and 2, each of the plurality of pin assemblies 19 is received in the respective hole 21 in the upper part 9 of the chuck body 3 so that top surface 29 of the main body 22 of the pin assembly 19 is flush or substantially flush with a surrounding surface of the upper part 9, so that only the longitudinal protrusion 25 protrudes from the hole 21 above the upper surface 13 of the upper part 9.

(36) The top surface 29 of the main body of the pin assembly 19 can therefore contact an underside of a semiconductor wafer received on the upper surface 13 of the upper part 9.

(37) As shown in FIG. 1, the chuck body 3 comprises a rotation mechanism for driving rotation of the gears 23 of the pin assemblies 19, so as to rotate the pin assemblies 19.

(38) In particular, the chuck body 3 includes a second gear 35 that is rotatably mounted in the chuck body via bearings 37 in the chuck body 3. The second gear 35 can therefore be rotated within the chuck body 3 relative to the chuck body 3.

(39) The second gear 35 includes a gear rim 39 that is coupled (meshed) to the gears 23 of each of the pin assemblies 19. Therefore, rotation of the second gear 35 causes simultaneous rotation of the gears 23 of each of the pin assemblies 19, and therefore simultaneous rotation of each of the pin assemblies 19.

(40) A driving means, for example an electric motor, is coupled to the second gear 35 to drive rotation of the second gear 35.

(41) As can be understood from FIG. 1, for example, rotation of a pin assembly 19 will cause the longitudinal protrusion 25 to move closer to, or further away from, a centre of the upper surface 13 of the upper part 9 of the chuck body 3, depending on the rotational position of the longitudinal protrusion 25.

(42) The pin assemblies 19 are arranged so that their longitudinal protrusions 25 move in synchronisation as the pin assemblies 19 are rotated by the second gear 35. In other words, a distance from each of the longitudinal protrusions 25 to the centre of the upper surface 13 is the same for all of the pin assemblies 19 as the pin assemblies 19 rotate.

(43) The pin assemblies 19 are rotatable relative to the chuck body 3 between a gripping configuration in which the pin assemblies 19 can grip a semiconductor wafer positioned on the upper surface 13, and a non-gripping configuration in which the pin assemblies 19 do not grip the semiconductor wafer.

(44) In particular, in the gripping configuration the pin assemblies 19 are rotated so that the longitudinal protrusions 25 contact an outer edge of the semiconductor wafer and apply pressure to the semiconductor wafer. The circular arrangement of the pin assemblies 19 means that the longitudinal protrusions therefore grip and hold the semiconductor wafer, preventing lateral movement of the semiconductor wafer. In the non-gripping configuration, the pin assemblies 19 are rotated so that the longitudinal protrusions 25 do not contact the outer edge of the semiconductor wafer, such that the semiconductor wafer is not laterally constrained.

(45) The apparatus typically includes a nozzle for dispensing a processing liquid onto a surface of the semiconductor wafer. Typically, the processing liquid is dispensed onto an opposite surface of the semiconductor wafer to a surface of the semiconductor wafer that faces the chuck body 3. For example, the processing liquid may be HF acid that is used to etch a surface of the semiconductor wafer.

(46) As the chuck 1 is spun during the processing operation, processing liquid that is dispensed onto the surface of the semiconductor wafer will move radially outwards across the surface of the semiconductor wafer, towards the edge of the semiconductor wafer. Some of the processing liquid will therefore come into contact with the pin assemblies 19 that are positioned around the periphery of the semiconductor wafer.

(47) Since the fit between the pin assemblies 19 and the holes 21 is not an interference fit, to allow rotation of the pin assemblies 19 relative to the holes 21, some of the processing liquid will infiltrate into the holes 21 between the outer surface of the pin assembly 19 and the inner surface of the hole 21.

(48) The second gear 35 is made of metal which may be subject to corrosion if it comes into contact with processing liquid such as HF. Therefore, it is desirable to prevent the processing liquid from reaching the second gear 35.

(49) In order to achieve this, as shown in FIG. 3A, a first circumferential groove 41 is provided around the circumference of the main body 22 of the pin assembly 19.

(50) An O-ring 43 is seated in the first circumferential groove 41 around the circumference of the main body 22.

(51) A width or thickness of the O-ring 43 is greater than a depth of the first circumferential groove 41, so that part of the O-ring 43 extends radially outwards from the first circumferential groove 41 beyond an outer surface of the main body 22 adjacent to the first circumferential groove 41.

(52) The O-ring 43 in this embodiment comprises a perfluoroelastomer material that is coated with a PTFE based coating. More specifically, the O-ring 43 in this embodiment comprises an O-ring formed of CHEMRAZ 551 that is coated with an ENDURO LF10 coating.

(53) More generally, a suitable O-ring 43 comprises an elastomer material that is coated with a material providing a lower sticking force with the inner surface of the hole 21 than would be provided by the elastomer material. The elastomer material therefore provides a suitable seal between the pin assembly 19 and the hole 21, whereas the coating material minimises friction between the O-ring 43 and the hole 21, so that the pin assembly 19 can be controllably rotated within the hole 21 without sticking.

(54) The O-ring 43 is fitted around the circumference of the main body 22 inside the first circumferential groove 41, such that the O-ring 43 grips the main body 22. The O-ring 43 therefore rotates together with the main body 22.

(55) When the pin assembly 19 is positioned in the respective hole 21, as illustrated in FIG. 1, the O-ring 43 contacts an inner surface of the hole 21 and is compressed by the inner surface of the hole 21.

(56) The O-ring 43 therefore provides a seal between the pin assembly 19 and the hole 21 that extends all the way around the circumference of the pin assembly 19, thereby preventing processing liquid from penetrating further into the hole 21 than the position of the O-ring 43. Processing liquid is therefore prevented from reaching the second gear 35.

(57) As mentioned above, the elastomer material in the O-ring 43 ensures there is a good seal between the O-ring 43, the main body 22 and the inner surface of the hole 21, so that infiltration of processing liquid into the hole 21 beyond the position of the O-ring 43 is prevented or substantially prevented.

(58) However, an O-ring 43 made of purely elastomeric material may provide a high sticking force between the O-ring 43 and the inner surface of the hole 21, such that it is difficult to controllable rotate the pin assemblies 19. Therefore, it is preferable for the O-ring 43 to include the coating material that minimises friction between the O-ring 43 and the hole 21, so that the pin assembly 19 can be controllably rotated within the hole 21 without sticking.

(59) Providing the first circumferential groove 41 may reduce a strength and/or Young's modulus of the main body 22 of the pin assembly 19. Therefore, as shown in FIG. 3A, it is advantageous for the insert 33 to extend to at least the position of the first circumferential groove 41, and preferably to a position beyond the position of the first circumferential groove 41. The insert 33 can there reinforce the main body 22 at the position where the main body 22 is weakened by the first circumferential groove 41.

(60) As shown in FIGS. 3A and 3C, a second circumferential groove 45 is also provided around the circumference of the main body 22 of the pin assembly 19. The second circumferential groove 45 is further from the first end of the main body 22 than the first circumferential groove 41. Put another way, the second circumferential groove 45 is closer to the longitudinal protrusion 25 than the first circumferential groove 41.

(61) As shown in FIG. 1, the upper part 9 of the chuck body 3 includes passageways 47 that are arranged so that when the pin assemblies 19 are arranged in the holes 21, the passageways 47 are communicated (in fluid communication, i.e. gas communication) with the second circumferential grooves 45 of the pin assemblies 19.

(62) More specifically, the passageways 47 extend from the holes 21 to an outside of the chuck body 3.

(63) As mentioned above, gas is supplied to a space beneath a semiconductor wafer from the gas supply chamber 15 and the plurality of holes 17. A gas pressure above the upper part 9 of the chuck body 3 may therefore be greater than a gas pressure around the sides of the chuck body 3. This pressure difference may cause a flow of gas from above the upper part 9 of the chuck body 3, into the holes 21, to the second circumferential groove 45 of the pin assemblies 19, and through the passageways 47 to the outside of the chuck body 3.

(64) Some of the processing fluid that infiltrates into the holes 21 may be collected in the second circumferential grooves 45 and then carried out of the holes 21 through the passageways 47 by the flow of the gas.

(65) Therefore, infiltration of processing liquid into the holes 21 may also be restricted by the gas flow through the second circumferential grooves 45 of the pin assemblies 19.

(66) In an alternative embodiment, the O-ring 43 may instead be seated in a circumferential groove formed on an inner surface of the hole, and may not rotate relative to the hole. Therefore, the pin assembly 19 may rotate within the hole relative to the O-ring 43.

(67) The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

(68) While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

(69) For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

(70) Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

(71) Throughout this specification, including the claims which follow, unless the context requires otherwise, the word comprise and include, and variations such as comprises, comprising, and including will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

(72) It must be noted that, as used in the specification and the appended claims, the singular forms a, an, and the include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from about one particular value, and/or to about another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent about, it will be understood that the particular value forms another embodiment. The term about in relation to a numerical value is optional and means for example +/10%.