US20050133158A1

US20050133158A1 - Mask handler apparatus

Info

Publication number: US20050133158A1
Application number: US10/741,588
Authority: US
Inventors: Khiem Nguyen; Alfred Mak
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2003-12-19
Filing date: 2003-12-19
Publication date: 2005-06-23

Abstract

Method and apparatus for supporting a substrate in a semiconductor substrate processing system are provided. A substrate is supported on two substrate support each having an inclined surface for receiving a portion of the substrate while minimizing contact with the substrate and guides for centering the substrate on the inclined surface. In one aspect, the two substrate supports are position facing each other on a ring disposed in a loadlock chamber with the substrate supported therebetween. Multiple sets of the substrate supports may be used to hold multiple substrates at a time in the loadlock chamber.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
Embodiments of the present invention generally relate to apparatus and methods for supporting and transferring substrates during photomask fabrication.
2. Description of the Related Art
A technique commonly used to form precise patterns on substrates is photolithography. In conventional photolithographic processes, a photoresist material is applied on a substrate layer to be etched. A light source emitting ultraviolet (UV) light is typically used to expose the photoresist layer to chemically alter the composition of the photoresist. However, the photoresist layer is only selectively exposed. In this respect, a photomask, or “reticle,” is positioned between the light source and the substrate being processed. The photomask contains the desired configuration of features for the substrate. The exposed, or alternatively, the unexposed photoresist material is then removed to expose the underlying material of the substrate. The retained photoresist material remains as an etch resistant pattern on the substrate. The exposed underlying material may then be etched to form the desired features in the substrate, i.e., contacts, vias, or other features.
Photolithographic photomasks, or reticles, typically comprise a substrate of an optically transparent silicon based material, such as quartz. A light-shielding layer of metal, typically chromium, is patterned on the surface of the substrate. The metal layer is patterned and etched to form features which define the pattern, and correspond to the dimensions of the features to be transferred to a substrate, such as a semiconductor substrate.
The deposition and etching processes employed to fabricate the photomask requires that the substrate be transferred and supported within a processing system. It has become desirable to utilize processing equipment and systems which are configured for processing the substrates themselves when fabricating the photomasks. However, these systems are typically configured to process circular substrates, and must be reconfigured to support and transfer rectangular photomasks. In addition, the systems used to support and transport the substrates used in photomask fabrication must carefully handle the substrates to prevent scratches and other defects from being formed on the substrates. These defects can alter the light transmission properties of the substrates and result in defective photomasks.
Therefore, there is a need for a method and apparatus for transferring and supporting substrates in processing systems which minimizes defect formation.

SUMMARY OF THE INVENTION

The present invention generally provides an apparatus to minimize defect formation in a substrate during processing and handling of substrates in a plasma etch chamber by supporting a portion of a substrate in a chamber to minimize contact between the substrate and the chamber components during processing.
In one aspect, an apparatus is provided for supporting a substrate including a base plate having an inner perimeter and an outer perimeter, a substrate support member extending horizontally from the inner perimeter of the base plate, at least one substrate support guide extending horizontally from the inner perimeter of the base plate and disposed adjacent the substrate support member, wherein the substrate support member and the at least one substrate support guide are adapted to receive a portion of a substrate.
In another aspect, an apparatus is provided for supporting a substrate including a ring, a plurality of spacers disposed on the ring, a plurality of substrate receiving members disposed on the plurality of spacers, wherein the substrate receiving members comprise a base plate having an inner perimeter and an outer perimeter, at least one substrate support guide extending horizontally from the inner perimeter of the base plate and disposed adjacent the substrate support member, wherein the substrate support member and the at least one substrate support guide are adapted to receive a portion of a substrate and the inner perimeter of the base plates are positioned to face an axis of the ring.
The apparatus may be used in a loadlock chamber further including one or more walls defining an enclosure, the walls having a sealable loading port selectively sealable by a door and at least one substrate transfer slot selectively sealable by one or more slit valves, the substrate transfer slots disposed substantially opposite of the loading port, at least one substrate support disposed in the enclosure, each substrate support including a ring, a plurality of spacers disposed on the ring, a plurality of substrate receiving members disposed on the plurality of spacers, wherein the substrate receiving members comprise a base plate having an inner perimeter and an outer perimeter, a substrate support member extending horizontally from the inner perimeter of the base plate, and at least one substrate support guide extending horizontally from the inner perimeter of the base plate and disposed adjacent the substrate support member, wherein the substrate support member and the at least one substrate support guide are adapted to receive a portion of a substrate and the inner perimeter of the base plates are position to face an axis of the ring. The loadlock chamber may also be used in a substrate processing system comprising a transfer chamber, at least the one processing chamber coupled to the transfer chamber, and a substrate handler disposed in the transfer chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
FIG. 1 is a top schematic view of a radial cluster tool for batch processing of semiconductor substrates;
FIG. 2 is a perspective view of one embodiment of a loadlock chamber having a substrate support ring disposed therein;
FIG. 3 is a perspective view of one embodiment of a substrate support ring; and
FIGS. 4A-4G are schematic views of one embodiment of the substrate support member described herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Aspects of the invention will be described below in reference to a photolithographic reticle, or photomask, etch system having an inductively coupled plasma etch chamber. The photomask etch system may be a cluster tool similar to that shown in FIG. 1 is a Centura™ processing system available from Applied Materials, Inc. of Santa Clara, Calif. Suitable inductively coupled plasma etch chambers include the ETEC Tetra™ photomask etch chambers, such as the ETEC Tetra I™ photomask etch chamber and the ETEC Tetra II™ photomask etch chamber, available from ETEC of Hayward, Calif., or optionally, a Decoupled Plasma Source DPS™ processing chambers, such as the DPS I™, DPS II™, and DPS +™ processing chambers available from Applied Materials, Inc., of Santa Clara, Calif. Other process chambers may be used including, for example, capacitively coupled parallel plate chambers and magnetically enhanced ion etch chambers, as well as inductively coupled plasma etch chambers of different designs. Although the processes are advantageously performed with the apparatus described herein, the description of the processing chambers and cluster tool is illustrative and should not be construed or interpreted to limit the scope of aspects of the invention.
FIG. 1 is a plan view of a vacuum cluster tool 100 suitable for use with the apparatus of the invention described above. The vacuum cluster tool includes multiple substrate processing chambers 112 mounted on a centralized vacuum chamber 114, such as a transfer chamber, for transferring a substrate from a substrate support in one or more load lock chambers 116, to one or more process chambers 112.
Transfer of a substrate 218 between the process chambers 112 is typically managed by a substrate handling module, or substrate handier, 118, preferably with the substrate handling blade 150 mounted thereon. The substrate handler 118 is located in the central transfer chamber 114. After a substrate is processed, the substrate is retrieved from the processing chambers 112 and transferred to one or more of the load lock chambers 116 and into one or more substrate cassette (not shown) disposed within the one or more load lock chambers 116. The substrates can then be retrieved from the loadlock chambers 116 and transferred to the next system for additional processing. In photomask manufacturing processing, the process chambers 112 are etching chambers, preferably plasma etching chambers
FIG. 2 is a perspective view of one embodiment of a loadlock chamber 116. The loadlock chamber 116 includes a sidewall 200, a bottom 204 and a lid (not shown). The sidewall 200 defines a loadlock loading port 208 for loading substrates into and unloading substrates out of the system 100. Passage 210 is disposed in the sidewall 202 opposite the loading port 208 to allow substrates to be moved from the loadlock chamber 116 into the transfer chamber 114. Slit valves and slit valve actuators are used to seal the passage 210 and loading port 208 when isolation or staged vacuum is desired. A service port 214 is disposed on one end of the loadlock chamber 116 to provide service and visual access to the loadlock chamber. 116.
A substrate support ring 220 is disposed within the loadlock chamber 116 to support the substrates 218 in a spaced relationship in the loadlock chamber 116 so that a substrate handler 118 can pass between the substrates 218 to place and remove substrates 218 from the loadlock 116. The substrate support ring 220 preferably supports a plurality of substrates 218 in a vertically displaced arrangement on substrate receiving members 222 disposed on the substrate support ring 220 as shown in FIGS. 3 and 4A-4E.
The substrate receiving members 222 are typically disposed in pairs having an inward facing orientation and are supported in spaced relation by spacers (not shown). The substrate supporting ring 220 may hold a plurality of sets of substrate receiving members 222 and may be vertically disposed from each other at a sufficient distance to allow a substrate handler to position and remove substrates 218 therefrom, such as a distance between about 0.1 inches and about 6 inches, for example, about 0.6 inches to about 0.7 inches apart. In the embodiment shown in FIG. 2, two sets of two substrate receiving members are provided on the substrate support ring 220 to support a total of two substrates.
The substrate receiving members 222 are adapted to define an opening 217 that a substrate handler blade. 150 can be moved to transfer a substrate with minimal contact between components of the system. An example of a suitable substrate handler blade is described in U.S. Pat. No. 6,537,011 issued on Mar. 25, 2003, and incorporated herein by reference to the extent not inconsistent with the disclosure and claimed aspects herein. While not shown, an actuator may be coupled to the loadlock 116 to raise and lower the loadlock to vertically displace the substrate receiving members 222 to align and receive substrates from a plane of the substrate handler.
An on-board vacuum pump (not shown) is mounted on the system 100 adjacent the loadlock chamber 116 and the transfer chamber 114 to pump down the loadlock chamber 116 and the transfer chamber 114. An exhaust port (not shown) is disposed through the bottom of the loadlock chamber 116 and is connected to the pump via exhaust line. The pump is preferably a high vacuum turbo pump capable of providing milliTorr pressures with very low vibration.
Referring to FIG. 3, the substrate support ring 220 comprises an annular ring structure 230 having attachment structures 232, spacers 234, and substrate receiving members 222 coupled to the spacers 234. The annular ring structure 230 typically comprises a substantially inert material to processing gases used in the processing chambers, such an inert material may include aluminum or aluminum oxide. The annular ring structure includes an outside perimeter 236 congruent with the inside perimeter of the loadlock chamber for attachment thereto. The annular ring structure 230 may also include one or more attachment structure 232 disposed at the outside diameter for affixation to the inside of the loadlock chamber. The attachment structures 232 of the annular ring structure 230 may be formed in any variable shape to adapt to match any configuration or shape of a loadlock chamber. The inner perimeter 238 of the ring is circular or substantially circular, but may vary on the structure of the loadlock chamber or desires of the operator.
Spacers 234 are adapted to be mounted on the annular ring structure 230 and may be further adapted to be mounted on the substrate receiving members 222. The spacers 234 include one or more apertures for receiving a fastener 235 and may also have one or more protrusion for mating with apertures in the substrate receiving members 222 or annular ring structure 230 surface. Multiple spacers and corresponding substrate receiving members 222 may be aligned and secured by one or more fasteners to provide a stack for receiving more than one substrate. The spacers 234 and the substrate receiving members 222 can form sets that may be repeatedly stacked to form any number vertically displaced sets as the loadlock will physically allow. The spacers 234 and the substrate receiving members 222 are configured on the annular ring structure vertically above or below the plane of the annular ring structure 230 and are configured to define an opening 217 for a substrate handler to position and remove substrates therefrom. The spacers 234 typically provide a spacing of between about 0.1 inches and six inches between substrate receiving members 222 mounted thereon and the ring 230, for example, the spacer 234 may have a thickness of about 0.625 inches and provide a distance between substrate receiving members of at least that distance
The spacers are typically disposed diametrically opposed from each other on the annular ring structure 230. However, variation in the number and orientation of the spacers 234 may occur for supporting substrates in the loadlock chamber. The spacers are made of a material that is inert or substantially inert with etching gases or processing gases that may contact the spacers, such as aluminum or aluminum oxide, as well as suitable polymers or rubbers.
Alternatively, while not shown, the spacers 234 may be adapted to have one or more shelves or lips to provide additional contact surface with the substrate receiving members 222 to help distribute stress or weight when receiving a substrate. The shelf or lip may be a parallel extension of a surface of the spacer 234 that contacts the substrate receiving surface 222, or alternatively, annular ring structure 230.
FIGS. 4A, 4B, and 4E are cross-sectional and perspective views of the substrate receiving member 222 of FIG. 3. The substrate receiving member 222 includes a base plate 250 having an upper surface 252, an outer perimeter 254, and an inner perimeter 256. The outer perimeter 252 may be co-existing with the outer perimeter 236 of the ring structure 230 and adapted to be coupled with the spacers 234. The outer perimeter may be further adapted to conform to the shape of portions of the ring structure 230. The inner perimeter is defined by a substrate support member 260, at least one substrate support guide 270, and optionally, one or more recesses 275, and is adapted to receive a portion of a substrate. The substrate receiving member 222 may comprise a material inert to processing gases, such as aluminum or aluminum oxide. The base plate 250, a substrate support member 260, and the at least one substrate support guide 270, may be individual components coupled together or may be formed from a single piece of material.
FIGS. 4C, 4D, and 4F are partial cross-sectional views of the substrate support member 260. The substrate support member 260 includes an angular substrate support portion 261, a vertical support portion 267, or both. The substrate support member may comprise only angular substrate support portions 261 or only vertical support portions 267. Generally, a combination of angular substrate support portions 261 and vertical support portions 267 comprise the substrate support member 260. In one embodiment of the substrate support member 260 includes two portions of the angular support portion 261 disposed on either side of a vertical support portion 267. The length of the respective portions of the angular substrate support portion 261 and the vertical support portion 267 and the substrate support member 260 may vary. In one example, the substrate support member comprises approximately 4 inches in length with two 0.5 inch angular substrate support portion disposed on either side of a three inch vertical support portion 267.
Referring to FIGS. 4C and 4F, the angular substrate support portion 261 includes an upper surface 262, an outer surface 263, and an inner surface 265. The inner surface 265 includes an upper substrate aligning surface 264 which is disposed at an incline from the upper surface 262. The incline may comprise a portion or all of the upper substrate aligning surface 264. The upper aligning surface 264 may have an angle β from the normal of between about 5° and about 30°, such as 15°. The upper aligning surface 264 provides gravity assisted gross alignment of a substrate 218 received thereon. An example of a substrate aligning surface is disclosed in co-pending U.S. patent application Ser. No. 10/689,783 [Atty. Docket No. APPM/8348], filed on Oct. 21, 2003, and entitled “Mask Etch Processing Apparatus”, which is incorporated herein by reference to the extent not inconsistent with the disclosure and claimed aspects herein.
The lower portion 266 of the substrate support member 260 has an inclined surface for receiving the substrate thereon, such as the edge of the substrate. The surface is inclined at an angle a between about 2° and about 7°, preferably between about 2.5° and about 5°, for example, about 2.5°. The inclination of the substrate support member 260 minimizes the surface area contact between the substrate 218 and the substrate support member 260 as shown in FIG. 4G. The inclined surface and the lower portion 266 also assist in centering the substrate as it is received thereon.
Referring to FIG. 4D, the vertical support portion 267 includes one or more substantially normal portions having an upper portion 268, a substantially horizontal lower portion 269, and a substantially vertical portion 271 disposed between the upper portion 268 and substantially horizontal lower portion 269. The substantially vertical portion 271 may have an angle of about normal, 90°, to the substantially horizontal lower portion 269, and alternatively, may have an angle θ up to about 30°, for example, about 15°. The lower portion 269 of the substrate support member 260 has a substantially horizontal surface of about 0°, and alternatively, may have an angle of up to about 5°, for example, about 2.5°. The substrate 218 contacts the substantially horizontal lower portion 269 when supported by the vertical support portion 267. In a substrate support member 260 having angular support portions 261 and vertical support portions 267, the substrate 218 has limited or no contact with the substantially horizontal lower surface 269 and the surface area contact between the substrate 218 and the substrate support member 260 is minimized.
The substrate receiving member 222 may further comprise one or more substrate support guides 270. The substrate support guides 270 extend from the base plate 252 along a substantially horizontal plane with the base plate 252. The substrate support guides are generally formed at the ends of the inner perimeter 256 on either side of the substrate support member 260. The substrate support guides are adapted to contact or enclose the sides of a substrate 218 positioned on the substrate support member 260 of the substrate receiving member 222.
The substrate support guides include an inner surface 271 and an outer surface 272. The inner surface 271 has a thickness of approximately the thickness of the base plate 252 and at least a portion up to the complete thickness of the inner surface 271 is angled. The angled surface comprises an inwardly sloping angle θ from the normal of between about 5° and about 30°, such as 15°. In one embodiment of the inner surface 271, the angled surface has the same angle as the upper aligning surface 264 of the angular support portion 261. The angled inner surface 271 is believed to further minimize contact with a substrate 218 disposed thereon. Optionally, recesses 275 are disposed between the substrate support guides 270 and the substrate support member 260 to also further minimize contact with a substrate 218 disposed thereon.
The substrate support member 260 is generally formed from of an etch resistant, high temperature resistant material, such as aluminum or aluminum oxide, to enable the substrate support member 260 to be used repetitively in the etching process without damage such as scratching or deformation.
While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. An apparatus for supporting a substrate, comprising:

a base plate having an inner perimeter and an outer perimeter;

a substrate support member extending horizontally from the inner perimeter of the base plate;

at least one substrate support guide extending horizontally from the inner perimeter of the base plate and disposed adjacent the substrate support member, wherein the substrate support member and the at least one substrate support guide are adapted to receive a portion of a substrate.

2. The apparatus of claim 1, wherein the substrate support member comprises a linear surface extending a length of the inner perimeter and the linear surface comprises an angular portion having an upper portion, a lower portion, and at least a partial tapered portion disposed between the upper portion and the lower portion.

3. The apparatus of claim 2, wherein the lower portion has an inclined surface between about 2° and about 7°.

4. The apparatus of claim 3, wherein the lower portion has an inclined surface of about 2.5°.

5. The apparatus of claim 2, wherein the tapered portion has a angle from normal of between about 5° and about 60°.

6. The apparatus of claim 2, wherein the linear surface further comprises one or more substantially normal portions having an upper portion, a substantially horizontal lower portion, and a substantially vertical portion disposed between the upper portion and substantially horizontal lower portion.

7. The apparatus of claim 5, wherein the linear surface comprises a substantially normal portion disposed between two angular portions of the linear surface.

8. The apparatus of claim 2, wherein the substrate support guides are disposed on the inner perimeter of the base plate and on at least opposing sides from the substrate support member.

9. The apparatus of claim 6, wherein the substrate support guides are adapted to position a substrate on the substrate support member.

10. The apparatus of claim 1, wherein the apparatus comprises an etch resistant material.

11. An apparatus for supporting a substrate, comprising:

a ring;

a plurality of spacers disposed on the ring;

a plurality of substrate receiving members disposed on the plurality of spacers, wherein the substrate receiving members comprise:

a base plate having an inner perimeter and an outer perimeter;

at least one substrate support guide extending horizontally from the inner perimeter of the base plate and disposed adjacent the substrate support member, wherein the substrate support member and the at least one substrate support guide are adapted to receive a portion of a substrate and the inner perimeter of the base plates are positioned to face an axis of the ring.

12. The apparatus of claim 11, wherein the substrate support member comprises a linear surface extending a length of the inner perimeter and the linear surface comprises an angular portion having an upper portion, a lower portion, and at least a partial tapered portion disposed between the upper portion and the lower portion.

13. The apparatus of claim 12, wherein the linear surface further comprises one or more substantially normal portions having an upper portion, a substantially horizontal lower portion, and a substantially vertical portion disposed between the upper portion and substantially horizontal lower portion.

14. The apparatus of claim 13, wherein the linear surface comprises a substantially normal portion disposed between two angular portions of the linear surface having an upper portion, a lower portion, and at least a partial tapered portion disposed between the upper portion and the lower portion.

15. The apparatus of claim 12, wherein the substrate support guides are disposed on the inner perimeter of the base plate and on at least opposing sides from the substrate support member.

16. The apparatus of claim 11, wherein the ring comprises an etch resistant material.

17. The apparatus of claim 11, wherein the at least two spacers are disposed on opposing sides of the ring from each other and a substrate receiving member is disposed on each of the at least two spaces, wherein the substrate support members of each substrate receiving member are opposed to each other.

18. The apparatus of claim 17, wherein the apparatus comprises a first set of spacers disposed on opposing sides of the ring from each other with a first set of substrate receiving member facing an inward direction disposed on the first set of spaces and a second set of spacers disposed on the first set of substrate receiving members and a second set of substrate receiving members facing an inward direction disposed on the second set of spacers.

19. The apparatus of claim 18, wherein the ring is adapted to be secured to a inner portion of a processing chamber.

20. A loadlock chamber, comprising:

one or more walls defining an enclosure, the walls having a sealable loading port selectively sealable by a door and at least one substrate transfer slot selectively sealable by one or more slit valves, the substrate transfer slots disposed substantially opposite of the loading port;

at least one substrate support disposed in the enclosure, each substrate support comprising:

a ring;

a plurality of spacers disposed on the ring;

a base plate having an inner perimeter and an outer perimeter;

a substrate support member extending horizontally from the inner perimeter of the base plate; and

at least one substrate support guide extending horizontally from the inner perimeter of the base plate and disposed adjacent the substrate support member, wherein the substrate support member and the at least one substrate support guide are adapted to receive a portion of a substrate and the inner perimeter of the base plates are position to face an axis of the ring.

21. The loadlock chamber of claim 20, wherein the substrate support member comprises a linear surface extending a length of the inner perimeter and the linear surface comprises an angular portion having an upper portion, a lower portion, and at least a partial tapered portion disposed between the upper portion and the lower portion.

22. The loadlock chamber of claim 21, wherein the linear surface further comprises one or more substantially normal portions having an upper portion, a substantially horizontal lower portion, and a substantially vertical portion disposed between the upper portion and substantially horizontal lower portion.

23. The loadlock chamber of claim 22, wherein the linear surface comprises a substantially normal portion disposed between two angular portions of the linear surface having an upper portion, a lower portion, and at least a partial tapered portion disposed between the upper portion and the lower portion.

24. The loadlock chamber of claim 21, wherein the substrate support guides are disposed on the inner perimeter of the base plate and on at least opposing sides from the substrate support member.

25. The loadlock chamber of claim 20, wherein the ring comprises an etch resistant material.

26. The loadlock chamber of claim 20, wherein the at least two spacers are disposed on opposing sides of the ring from each other and a substrate receiving member is disposed on each of the at least two spaces, wherein the substrate support members of each substrate receiving member are opposed to each other.

27. The loadlock chamber of claim 26, wherein the apparatus comprises a first set of spacers disposed on opposing sides of the ring from each other with a first set of substrate receiving member facing an inward direction disposed on the first set of spaces and a second set of spacers disposed on the first set of substrate receiving members and a second set of substrate receiving members facing an inward direction disposed on the second set of spacers.

28. The loadlock chamber of claim 27, wherein the ring is adapted to be secured to a inner portion of a processing chamber.

29. The loadlock chamber of claim 20, further comprising:

a transfer chamber coupled to the loadlock chamber;

at least one processing chamber coupled to the transfer chamber:

a substrate handler disposed in the transfer chamber and in substrate communication with the loadlock and each of the at least one processing chamber.