EP3999912A1

EP3999912A1 - Methods and apparatus for post exposure processing

Info

Publication number: EP3999912A1
Application number: EP20840683.5A
Authority: EP
Inventors: Alan Tso; Qiwei Liang; Lancelot HUANG; Gautam PISHARODY
Original assignee: Applied Materials Inc
Current assignee: Applied Materials Inc
Priority date: 2019-07-17
Filing date: 2020-06-25
Publication date: 2022-05-25
Also published as: EP3999912A4; TW202109732A; TW202347567A; JP2022540650A; JP7498257B2; TWI813889B; CN113994456B; CN113994456A; WO2021011166A1; KR20220020961A

Abstract

Embodiments described herein relate to methods and apparatus for post exposure processing. More specifically, embodiments described herein relate to field-guided post exposure bake (iFGPEB) chambers and processes, In one embodiment, a substrate is transferred into a post exposure process chamber and then raised to a pre-processing position by a plurality of lift pins. A substrate support is then raised to engage with the substrate and vacuum chuck the substrate thereon prior to iFGPEB processing.

Description

METHODS AND APPARATUS FOR POST EXPOSURE PROCESSING

BACKGROUND

Field

[0001] Embodiments of the present disclosure relate to methods and apparatus for processing a substrate, and more specifically, to methods and apparatus for improving photolithography processes.

Description of the Related Art

[0002] Integrated circuits have evolved into complex devices that can include millions of components (e.g., transistors, capacitors, and resistors) on a single chip. Photolithography is a process that may be used to form the components on the chip. Generally, the process of photolithography involves several stages. Initially, a photoresist layer is formed on a substrate. A chemically amplified photoresist may include a resist resin and a photoacid generator. The photoacid generator, upon exposure to electromagnetic radiation in the subsequent exposure stage, alters the solubility of the photoresist in the development process. The electromagnetic radiation may have any suitable wavelength, for example, a 193 nm ArF laser, an electron beam, an ion beam, or other suitable source. Excess solvent may then be removed in a pre-exposure bake process.

[0003] In an exposure stage, a photomask or reticle may be used to selectively expose certain regions of the substrate to electromagnetic radiation. Other exposure methods may be maskless exposure methods. Exposure to light may decompose the photo acid generator, which generates acid and results in a latent acid image in the resist resin. After exposure, the substrate may be heated in a post-exposure bake process. During the post exposure bake process, the acid generated by the photoacid generator reacts with the resist resin in the photoresist layer, changing the solubility of the resist of the photoresist layer during the subsequent development process.

[0004] After the post-exposure bake, the substrate, and, particularly, the photoresist layer may be developed and rinsed. Depending on the type of photoresist used, regions of the substrate that were exposed to electromagnetic radiation may either be resistant to removal or more prone to removal. After development and rinsing, the pattern of the mask is transferred to the substrate using a wet or dry etch process.

[0005] The evolution of chip design necessitates faster circuitry and greater circuit density. The demands for greater circuit density, in turn, necessitate a reduction in the dimensions of the integrated circuit components. As the dimensions of the integrated circuit components are reduced, more elements are placed in a given area on a semiconductor integrated circuit. Accordingly, lithography processes are utilized to transfer even smaller features onto a substrate to accommodate the shrinking dimensions of the integrated circuit components.

[0006] Precise and accurate lithography is largely dependent on the resolution of a photoresist layer disposed on a substrate to be patterned. In a recent development, an electrode assembly is utilized to provide an electric field to the photoresist layer disposed on the substrate prior to or after an exposure process so as to modify chemical properties of desired portions of the photoresist layer for improved exposure/development resolution. However, the challenges in implementing such systems have not been overcome.

[0007] Therefore, there is a need for improved methods and apparatus for improved immersion field guided post exposure bake process.

SUMMARY

[0008] The present disclosure generally relates to methods and apparatus for immersion field guided post exposure bake processes. In one embodiment, the method includes positioning a substrate on a plurality of lift pins within a first volume and moving the lift pins to a first position. A substrate support is moved to the first position to engage the substrate and then moved to a second position adjacent a second volume partially defined by the substrate and an electrode. A process fluid is introduced into the second volume and an electric field is generated between the electrode and the substrate.

[0009] In one embodiment, the method includes positioning a substrate on a plurality of lift pins within a first volume of a process chamber. The substrate is moved to a pre-processing position adjacent to a ceiling of the process chamber, upon which a substrate support is moved to the pre processing position to contact the substrate. The substrate is vacuum chucked to the substrate support and the substrate support is moved to a processing position to form a second volume in the process chamber. A process fluid is introduced into the second volume and an electric field is generated therein.

[0010] In one embodiment, the method includes positioning a substrate on a plurality of lift pins disposed at a first position within a first volume of the process chamber and moving the plurality of lift pins to a second position. A substrate support is moved to the second position to contact and vacuum chuck the substrate. The substrate support having the substrate chucked thereon is moved to a third position in the first volume, the disposition of the substrate support in the third position forming a second volume in the process chamber partially defined by the substrate. A process fluid is introduced into the second volume and an electric field is generated therein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, 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 exemplary embodiments and are therefore not to be considered limiting of its scope, and may admit to other equally effective embodiments.

[0012] Figure 1 illustrates operations of a method for processing substrates according to embodiments described herein. [0013] Figures 2 illustrates a process chamber at a first stage of the method of Figure 1 according to embodiments described herein.

[0014] Figure 3 illustrates the process chamber of Figure 2 at a second stage of the method of Figure 1 according to embodiments described herein.

[0015] Figure 4 illustrates the process chamber of Figure 2 at a third stage of the method of Figure 1 according to embodiments described herein.

[0016] Figure 5 illustrates the process chamber of Figure 2 at a fourth stage of the method of Figure 1 according to embodiments described herein.

[0017] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

DETAILED DESCRIPTION

[0018] Embodiments described herein relate to methods and apparatus for post exposure processing. More specifically, embodiments described herein relate to field-guided post exposure bake (iFGPEB) chambers and processes. In one embodiment, a substrate is transferred into a post exposure process chamber and then raised to a pre-processing position by a plurality of lift pins. A substrate support is then raised to engage with the substrate and vacuum chuck the substrate thereon prior to iFGPEB processing.

[0019] Figure 1 illustrates operations of a representative method 100 for processing substrates according to embodiments described herein. Figures 2-5 illustrate schematic, cross-sectional views of a substrate 201 within a process chamber 200 at different stages of the method 100. Thus, references to Figures 2-5 will be included in the discussion of Figure 1 and the method 100 where warranted. The method 100 for processing of the substrate 201 has multiple operations. The operations can be carried out in any order or simultaneously (except where the context excludes the possibility), and the method 100 can include one or more other operations which are carried out before any of the defined operations, between two of the defined operations, or after all the defined operations (except where the context excludes the possibility). Not all embodiments include all the operations described.

[0020] In general, the method 100 at operation 110 includes positioning the substrate 201 on a plurality of lift pins 266 disposed at a transfer position 270 within the process chamber 200 and heating a substrate support 208 to a desired temperature. At operation 120, the substrate 201 positioned on the lift pins 266 is elevated to a pre-processing position 272 while the substrate support 208 remains stationary. Subsequently, at operation 130, the substrate support 208 is raised to engage the substrate 201 in the pre processing position 272. At operation 140, the substrate support 208 is further elevated to a processing position 274, after which the substrate 201 is processed at operation 150.

[0021] Figure 2 illustrates the process chamber 200 at operation 110. In one embodiment, the process chamber 200 is configured for performing immersion field guided post exposure bake (iFGPEB) processes. As depicted in Figure 2, the chamber 200 includes a chamber body 202 having sidewalls 204 and a bottom 206 at least partially defining a volume 203. A slit valve 205 sized to accommodate passage of the substrate 201 therethrough is disposed in the sidewalls 204. In one embodiment, the chamber body 202 has a substantially cylindrical shape. In another embodiment, the chamber body 202 has a polygonal shape, such as a cubic shape or the like. The chamber body 202 is fabricated from a material suitable for maintaining a vacuum pressure therein, such as metallic materials. For example, the chamber body 202 is fabricated from aluminum, stainless steel, and alloys and combinations thereof. Alternatively, the chamber body 202 is fabricated from polymer materials such as polytetrafluoroethylene (PTFE) or high temperature plastics such as polyether ether ketone (PEEK).

[0022] A ceiling 210 is coupled to the chamber body 202 and further defines the volume 203. In one embodiment, the ceiling 210 is fabricated from a metallic material such as aluminum, stainless steel, and alloys and combinations thereof. In another embodiment, the ceiling 210 is fabricated from a polymer material such as PTFE, PEEK, and the like. The ceiling 210 may be formed from the same materials utilized to fabricate the chamber body 202. Alternatively, the ceiling 210 may be formed from different materials than the chamber body 202.

[0023] The ceiling 210 is coupled to and supports an electrode 212. In one embodiment, the electrode 212 is removably coupled to the ceiling 210. In another embodiment, the electrode 212 is fixedly coupled to the ceiling 210. The electrode 212 may be formed from an electrically conductive metallic material. In addition, the material utilized for the electrode 212 may be a non- oxidative material. The materials selected for the electrode 212 provide for desirable current uniformity and low resistance across a surface of the electrode 212. A first o-ring 214 is further coupled to the electrode 212 along an outer diameter of the electrode 212. The first o-ring 214 is also disposed in contact with a sidewall 216 of the ceiling 210. The first o-ring is 214 is configured to prevent process fluid from flowing behind the electrode 212 during processing.

[0024] A heat source 218, a temperature sensing apparatus 220, a power source 222, and a sensing apparatus 224 are coupled to the electrode 212. The heat source 218 provides power to one or more heating elements (not shown), such as resistive heaters, disposed within the electrode 212. The heat source 218 is configured to facilitate preheating of process fluid during iFGPEB processes. The heat source 218 may also be utilized to maintain a desired temperature of the process fluid during substrate processing in addition to or distinct from preheating the process fluid. In one implementation, the heat source 218 is configured to heat the electrode 212 to a temperature of between about 70 °C and about 150 °C, such as between about 90 °C and about 130 °C. For example, the heat source 218 is configured to heat the electrode 212 to a temperature of between about 100 °C and about 120 °C, such as about 110 °C. [0025] The temperature sensing apparatus 220, such as a thermocouple or the like, is communicatively coupled to the heat source 218 to provide temperature monitoring and facilitates heating of the electrode 212. The power source 222 is configured to supply, for example, between about 0 W and about 100 W, such as between about 25 W and about 75 W, to the electrode 212. Depending on the type of process fluid utilized, current generated by the power source 222 may be on the order of tens of nano amps to hundreds of milliamps. In one embodiment, the power source 222 is configured to generate electric fields ranging from about 0 V/mm to about 2000 V/mm. For example, the power source 222 is configured to generate electric fields ranging from about 100 V/mm to about 1800 V/mm, such as between about 500 V/mm and about 1200 V/mm, such as between about 800 V/mm and about 1000 V/mm. In some embodiments, the power source 222 is configured to operate in either voltage controlled or current controlled modes. In both modes, the power source 222 may output AC, DC, and/or pulsed DC waveforms. Square or sine waves may be utilized if desired. The power source 222 may be configured to provide power at a frequency of between about 0.1 Hz and about 1 kHz, such as a frequency between about 100 Hz and about 750 Hz, such as between about 250 Hz and about 500 Hz. The duty cycled of the pulsed DC power or AC power may be between about 5% and about 95%, such as between about 25% and about 75%.

[0026] The rise and fall time of the pulsed DC power or AC power may be between about 1 nanoseconds and about 1 milliseconds, such as between about 100 nanosecond and about 1 microsecond. The sensing apparatus 224, such as a voltmeter or the like, is communicatively coupled to the power source 222 to provide electrical feedback and facilitate control of the power applied to the electrode 212. The sensing apparatus 224 may also be configured to sense a current applied to the electrode 212 via the power source 222.

[0027] A first plurality of fluid ports 226 are formed in the ceiling 210 through the sidewall 216. A second plurality of fluid ports 228 are also formed in the sidewall 216 opposite the first plurality of fluid ports 226. The first plurality of fluid ports 226 are in fluid communication with a process fluid source 232 via a first conduit 234. The second plurality of fluid ports 228 are in fluid communication with a fluid outlet 236 via a second conduit 238. The process fluid source 232, either alone or in combination with other apparatus, is configured to preheat a process fluid to a temperature of between about 70 °C and about 150 °C, such as between about 80 °C and about 140 °C, prior to processing of the substrate 201 and deliver the fluid during an iFGPEB process. For example, the process fluids are heated to a temperature between about 100 °C and about 120 °C, such as about 110 °C.

[0028] In one embodiment, a purge gas source 250 is also in fluid communication with the first plurality of fluid ports 226 via the first conduit 234. Gases provided by the purge gas source 250 may include one or more of nitrogen, hydrogen, inert gases, and the like to purge a process volume 290 (shown in Figure 5) before, during, or after iFGPEB processing. When desired, purge gases may be exhausted from the process volume 290 via the fluid outlet 236.

[0029] The substrate support 208 is disposed in the volume 203. In one embodiment, the substrate support 208 is coupled to a shaft 244 disposed through an opening 240 in the bottom 206 of the chamber body 202. The substrate support 208 is raised and lowered within the volume 203 by an actuator assembly 246 coupled to the shaft 244. In some embodiments, the substrate support 208 is further rotatable about a central axis thereof.

[0030] A vacuum chuck 242 is coupled to the substrate support 208. The vacuum chuck 242 may be formed from a non-metallic material or other insulative material, such as a ceramic material or the like. Additionally, the vacuum chuck 242 may be formed from a non-oxidative material to substantially reduce or prevent the probability of substrate oxidation via reaction of the process fluid with the vacuum chuck 242. Similar to the electrode 212, the materials utilized for the vacuum chuck 242 provide for desirable current uniformity during processing of the substrate 201. Specifically, the materials utilized for the vacuum chuck 242 are selected to have a negligible influence on an electric field generated in the process chamber 200 during processing.

[0031] The vacuum chuck 242 is configured to support the substrate 201 thereon during processing and has a planar support surface 242A. The support surface 242A is sized to accommodate attachment of the substrate 201 thereon and for positioning adjacent to the ceiling 210. A vacuum source 258 is in fluid communication with the substrate support surface 242A. Generally, the vacuum source 258 is coupled to the vacuum chuck 242 through the substrate support 208. The vacuum source 258 is configured to vacuum chuck the substrate 201 to the support surface 242A of the vacuum chuck 242 during processing.

[0032] Similar to the electrode 212, the vacuum chuck 242 is coupled to a heat source 248, a temperature sensing apparatus 252, and a power source 254. The heat source 248, temperature sensing apparatus 252, power source 254, and sensing apparatus 256 may function similarly to the heat source 218, the temperature sensing apparatus 220, the power source 222, and the sensing apparatus 224. For example, the heat source 248 provides power to one or more heating elements, such as resistive heaters or ceramic heaters, disposed within the vacuum chuck 242. Generally, the heat source 248 is configured to heat the vacuum chuck 242 to facilitate heating of the substrate 201 and/or process fluid during iFGPEB processes. In one embodiment, the heat source 248 is configured to heat the vacuum chuck 242 to a temperature of between about 75 °C and about 150 °C, such as between about 100 °C and about 125 °C, such as between about 110 °C and about 120 °C. The temperature sensing apparatus 252, such as a thermocouple or the like, is communicatively coupled to the heat source 248 to provide temperature monitoring and facilitates heating of the vacuum chuck 242.

[0033] In one embodiment, a second o-ring 280 is disposed in the vacuum chuck 242 on the substrate support surface 242A. The second o-ring 280 may be positioned on the vacuum chuck 242 at a distance between about 1 mm and about 12 mm radially inward from an outer diameter of the substrate 201 when disposed thereon. For example, the second o-ring 280 may be positioned on the vacuum chuck 242 at a distance between about 2 mm and about 10 mm, such as between about 4 mm and about 8 mm, radially inward from an outer diameter of the substrate 201. It is contemplated that the second o-ring 280 may prevent the leakage of process fluid form a process volume 290 to a region behind the substrate 201 during processing.

[0034] The vacuum chuck 242 further includes a ledge 282 disposed radially outward of the second o-ring 280 and coupling the substrate support surface 242A to an upper surface 242B of the vacuum chuck 242. The upper surface 242B is disposed below and radially outward of the ledge 282 and the substrate support surface 242A. In one embodiment, a third o-ring 284 is disposed in the vacuum chuck 242 on the upper surface 242B. A first lower surface 215 of the ceiling 210 is shaped and sized to contact an edge region of the substrate 201 when the substrate support 208 is in the processing position 274. A second lower surface 217 of the ceiling 210 is shaped and sized to contact the vacuum chuck 242 adjacent to and extending radially inward from an outer diameter of the substrate support surface 242A. A third lower surface 219 of the ceiling 210 is shaped and sized to contact the upper surface 242B. In one embodiment, the third o-ring 284 contacts the third lower surface 219 when the substrate support 208 is disposed in the processing position 274. It is contemplated that the third o-ring 284 may prevent the leakage of process fluid from the process volume 290 beyond the outer diameter of the vacuum chuck 242 during processing.

[0035] The substrate support 208 and the vacuum chuck 242 each include a plurality of lift pin holes 262, 264, respectively. The plurality of lift pin holes 262 are aligned with the plurality of lift pin holes 264. A plurality of lift pins 266 are moveably disposed through the pluralities of lift pin holes 262, 264, as well as through a plurality of holes 241 in the chamber bottom 206. The plurality of lift pins 266 are coupled to a lift pin actuator 268 which displaces the lift pins 266 through the chamber bottom 206, the substrate support 208, and the vacuum chuck 242 between a transfer position 270, a pre-processing position 272 (shown in Figure 3), and a processing position 274 (shown in Figure 5).

[0036] At operation 110, the substrate 201 is transferred through the slit valve 205 and into the volume 203 by a robot blade or other suitable transfer device (not shown) and positioned on upper ends 267 of the plurality of lift pins 266. The upper ends 267 of the lift pins 266 are disposed at a transfer position 270 raised above the substrate support 208 but slightly lower than the slit valve 205. The substrate support 208 having the vacuum chuck 242 coupled thereto is positioned at a lowered position (e.g., against the chamber bottom 206) such that no contact is made between the substrate 201 and the substrate support surface 242A during operation 110. In one example, the upper ends 267 of the lift pins 266 are disposed a distance between about 10 mm and about 110 mm, such as between about 30 mm and about 90 mm, from the substrate support surface 242A. In another example, the upper ends 267 of the lift pins 266 are disposed a distance between about 50 mm and about 90 mm, such as between about 60 mm and about 80 mm, from the substrate support surface 242A. Upon positioning of the substrate 201 in the process chamber 200, the vacuum chuck 242 is heated by the heat source 248 to a temperature of between about 75 °C and about 150 °C, such as between about 100 °C and about 125 °C, for example, about 115 °C.

[0037] At operation 120 and depicted in Figure 3, the substrate 201 disposed on the lift pins 266 is elevated to a pre-processing position 272. The lift pin actuator 268 raises the plurality of lift pins 266 from the transfer position 270 to the pre-processing position 272. In one embodiment, the substrate 201 is moved from the transfer position 270 to the pre-processing position 272 in a period of between about 2 and about 6 seconds, such as between about 2 and about 4 seconds, such as about 3 seconds. In one embodiment, the substrate 201 is elevated to a pre-processing position 272 having a distance of between about 1 mm and about 25 mm from a lower surface 213 of the electrode 212, such as a distance of between about 5 mm and about 20 mm. For example, the pre-processing position 272 has a distance of between about 10 mm and about 15 mm, such as about 12 mm. [0038] At operation 130 and depicted in Figure 4, the substrate support 208 is raised to the pre-processing position 272 such that the substrate support surface 242A of the vacuum chuck 242 is slightly higher than or substantially co-planar with the top ends 267 of the lift pins 266. Thus, the substrate support 208 engages with the substrate 201 to support the substrate 201 thereon. The vacuum source 258 is then activated to vacuum chuck the substrate 201 to the support surface 242A of the vacuum chuck 242. In one embodiment, the substrate support 208 is raised to the pre processing position 272 and engages the substrate 201 in a period of between about 2 and about 5 seconds, such as between about 2 and about 4 seconds, such as about 3 seconds. By avoiding contact between the substrate support 208 and the substrate 201 prior to operation 130, the vacuum chuck 242 may be heated to a desired temperature without any direct thermal transfer to the substrate 201 , and heating of the substrate 201 may be delayed to begin at substantially the same time as application of the electric field during iFGPEB processing.

[0039] At operation 140 and depicted in Figure 5, after chucking the substrate 201 to the vacuum chuck 242, the substrate support 208 is raised to the processing position 274 in which the vacuum chuck 242 and the substrate 201 contact the ceiling 210. For example, the edge region of the substrate 201 contacts the first lower surface 215, an edge region of the substrate support surface 242A contacts the second lower surface 217, and the upper surface 242B and the third o-ring 284 contact the third lower surface 219. The disposition of the substrate support 208 in the processing position 274 results in the formation of the processing volume 290 between the substrate 201 and the electrode 212 that is fluidly sealed by the first o-ring 214, second o-ring 280, and third o-ring 284.

[0040] In one embodiment, the substrate support 208 is raised from the pre-processing position 272 to the processing position 274 in a period between about 0.1 seconds and about 2 seconds, such as between about 0.5 seconds and about 1.5 seconds. For example, the substrate support 208 is raised from the pre-processing position 272 to the processing position 274 in a period between about 0.75 seconds and about 1.25 seconds, such as about 1 second. Thus, the total time required to move a substrate from the transfer position 270 to the processing position 274 may be between about 0.1 seconds and about 3 seconds, such as between about 0.5 seconds and about 2.5 seconds. For example, the total time required to move the substrate 201 from the transfer position 270 to the processing position 274 is between about 1 second and about 2 seconds, such as about 1.5 seconds.

[0041] In one embodiment, the process volume 290 has a height 292 defined between the substrate 201 and the lower surface 213 of the electrode 212. In one example, the height 292 of the process volume 290 is between about 1 mm and about 10 mm, such as between about 2 mm and about 8 mm. For example, the height 292 of the process volume 290 is between about 4 mm and about 6 mm, such as about 5 mm. The relatively small distance between the substrate 201 and the electrode 212 reduces the volume of the process volume 290, enabling utilization of reduced quantities of process fluid during iFGPEB processing. Furthermore, a reduced height 292 provides a substantially more uniform electrical field across the surface of the substrate 201 and as a result, patterning characteristics during iFGPEB processing may be improved. Additionally, the power required to generate the desired electrical field and heat the process fluids during iFGPEB may be reduced.

[0042] After positioning of the substrate support 208 in the processing position 274 and formation of the process volume 290, the substrate 201 is exposed to an iFGPEB process at operation 150. During iFGPEB processing, the process volume 290 is filled with process fluid, for example a gas or a liquid, having a flow path originating from the process fluid source 232 and traveling through the first conduit 234. The process fluid exits the first conduit 234 through the first plurality of fluid ports 226 into the process volume 290. The flow rate of the process fluid into the process volume 290 may be modulated to reduce turbulence of the fluid within the process volume 290 and reduce or eliminate the formation of bubbles therein. For example the flow rate of the process fluid into the process volume 290 may be modulated between 1 L/min and about 12 L/min, such as between about 5 L/min and about 10 L/min. The process fluid may also be preheated to processing temperatures prior to introduction into the process volume 290. For example, the process fluid may be preheated by the process fluid source 232 to a temperature between about 70°C and about 170 °C, such as between about 90 °C and about 150 °C. For example, the process fluid is heated to a temperature of between about 110 °C and about 130 °C, such as about 120 °C.

[0043] Once the process volume 290 is filled with process fluid, the electric field is applied to the substrate 201 by the electrode 212. In one embodiment, the electric field may be applied to the substrate 201 for an amount of time between about 10 seconds and about 90 seconds, such as between about 25 seconds and about 75 seconds, such as between about 40 seconds and about 60 seconds, such as about 50 seconds. In some embodiments, the fluid disposed in the process volume 290 is stagnant during processing of the substrate 201. In some embodiments, the fluid volume of the process volume 290 is cycled or exchanged. In such embodiments, as the process volume 290 is filled with process fluid via the first conduit 234 and the first fluid ports 226, process fluid also exits the process volume 290 via the second fluid ports 228 and the second conduit 238 and is ultimately removed from the process chamber 200 at the fluid outlet 236. After application of the electric field, the process fluid may be drained from the process volume 290 and the substrate support 208 having the processed substrate 201 chucked thereon may be lowered.

[0044] The methods and apparatus described above enhance iFGPEB processing performance by reducing the amount of time a substrate is exposed to heat prior to application of an electric field. By engaging the substrate with a heated substrate support just prior to application of the electric field, unwanted thermal transfer between the heated substrate support and the substrate is minimized. Accordingly, random thermal diffusion of acids generated by a photoacid generator within a photoresist may be substantially decreased, thus reducing heat-triggered de-protection of the photoresist. The reduction in pre-processing de-protection of the photoresist enables enhanced development/exposure resolution of the photoresist by increasing control of the diffusion of charged species generated by the photoacid generator, and in turn, enables more precise transfer of circuit features during lithography.

[0045] In summation, apparatus and methods for improving iFGPEB processing are provided. Process chambers described herein enable efficient utilization of process fluid and improved application of electric field during iFGPEB operations. Photoresist resolution is also improved by reducing the amount of time the substrate is exposed to elevated temperatures prior to application of an electric field, thus reducing the reaction of photoresist chemical species prior to iFGPEB processing. Accordingly, iFGPEB processing operations can be improved by utilizing the apparatus and methods described herein.

[0046] While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

What is claimed is:

1. A substrate processing method, comprising:

positioning a substrate on a plurality of lift pins within a first volume, the plurality of lift pins disposed in a first position;

moving the plurality of lift pins having the substrate positioned thereon to a second position within the first volume;

moving a substrate support disposed within the first volume to the second position to engage the substrate;

moving the substrate support having the substrate engaged thereto to a third position adjacent a second volume; and

processing the substrate within the second volume.

2. The method of claim 1 , wherein upper ends of the lift pins are disposed at a distance between about 10 mm and about 100 mm from the substrate support when in the first position.

3. The method of claim 1 , wherein the substrate support is heated to a temperature between about 75 °C and about 150 °C prior to being moved to the second position.

4. The method of claim 3, wherein the substrate support is moved to the second position in a period between about 2 seconds and about 5 seconds after being heated.

5. The method of claim 1 , wherein the substrate support engages the substrate by vacuum chucking the substrate to an upper surface thereof.

6. The method of claim 1 , wherein the substrate support is moved from the second position to the third position in a period between about 0.1 seconds and about 2 seconds.

6441059_1 16

7. The method of claim 1 , wherein a total time to move the substrate from the first position to the third position is between about 0.1 seconds and about 3 seconds.

8. The method of claim 1 , wherein processing the substrate further comprises: introducing a process fluid to the second volume; and

generating an electric field within the second volume.

9. The method of claim 8, wherein a height of the second volume is defined between the substrate and an electrode disposed in a ceiling of the process chamber when the substrate is disposed in the third position.

10. The method of claim 9, wherein the height of the second volume is between about 1 mm and about 10 mm.

11. A substrate processing method, comprising:

positioning a substrate on a plurality of lift pins within a first volume of a process chamber;

moving the substrate to a pre-processing position adjacent to a ceiling of the process chamber;

moving a substrate support to the pre-processing position to contact the substrate;

vacuum chucking the substrate to the substrate support;

moving the substrate support having the substrate vacuum chucked thereon to a processing position, the moving of the substrate support to the processing position resulting in formation of a second volume in the process chamber;

introducing a process fluid to the second volume; and

generating an electric field within the second volume.

12. The method of claim 11 , wherein upper ends of the lift pins are disposed at a transfer position between about 30 mm and about 90 mm from the substrate support prior to moving to the pre-processing position.

6441059_1 17

13. The method of claim 12, wherein the substrate support is moved from the pre-processing position to the processing position in a period between about 0.5 seconds and about 1.5 seconds.

14. The method of claim 13, wherein a total time to move the substrate from the transfer position to the processing position is between about 0.5 seconds and about 2.5 seconds.

15. The method of claim 11 , wherein the substrate support is heated to a temperature between about 100 °C and about 125 °C prior to being moved to the pre-processing position.

16. The method of claim 15, wherein the substrate support is moved to the pre processing position in a period between about 2 seconds and about 4 seconds after heating.

17. The method of claim 11 , wherein the second volume is partially defined by the substrate and an electrode disposed in a ceiling of the process chamber when the substrate is disposed in the processing position.

18. The method of claim 17, wherein the second volume is fluidly sealed by one or more o-rings disposed in the substrate support or electrode.

19. The method of claim 18, wherein process fluid is introduced into the second volume at a flow rate between 1 L/min and 12 L/min.

20. A substrate processing method, comprising:

positioning a substrate on a plurality of lift pins disposed at a first position within a first volume of a process chamber;

moving the plurality of lift pins to a second position within the first volume of the process chamber;

moving a substrate support to the second position to contact and vacuum chuck the substrate;

6441059_1 18 moving the substrate support having the substrate chucked thereon to a third position in the first volume of the process chamber, the disposition of the substrate support in the third position forming a second volume in the process chamber, the second volume partially defined by the substrate;

introducing a process fluid to the second volume; and

generating an electric field within the second volume.

6441059_1 19