Patent Publication Number: US-2023161260-A1

Title: Chamber and methods of cooling a substrate after baking

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to the U.S. Provisional Patent Application Ser. No. 63/264,548 filed Nov. 24, 2021 of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Field 
     Embodiments of the present disclosure generally relate to methods and apparatus for processing a substrate. More specifically, the disclosure is directed towards methods and apparatus for cooling a substrate after exposure to radiation. 
     Description of the Related Art 
     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 components on a chip. Generally, the process of photolithography involves several stages. Initially, a photoresist layer is formed on a substrate. A chemically amplified photoresist typically includes a resist resin and a photoacid generator. The photoacid generator, upon exposure to electromagnetic radiation in a subsequent exposure stage, alters the solubility of the photoresist in the development process. The electromagnetic radiation may be generated by any suitable source, for example, a laser, an electron beam, an ion beam, or other suitable electromagnetic radiation source. The electromagnetic radiation is also selected with any desirable wavelength, for example, 193 nm or other suitable wavelength. 
     In the exposure stage, a photomask or reticle is used to selectively expose certain regions of the substrate to electromagnetic radiation. Other exposure methods include maskless exposure methods or the like. Exposure to light decomposes the photo acid generator, which generates acid and results in a latent acid image in the resist resin. After exposure, the substrate is disposed on a pedestal and heated in a post-exposure bake process in a process chamber. During the post-exposure bake process, the acid generated by the photoacid generator reacts with the resist resin, changing the solubility of the resist during the subsequent development process. 
     During the post bake process, a photoresist layer may reach temperatures of up to 400 degrees Celsius (° C.). The temperature controlled reaction of the resist resin continues in the resist resin until a temperature of about 70° C. or less. After the post-exposure bake, the substrate is removed from the process chamber and cooled in another location to stop the reaction in the resist resin. However, moving the substrate to a remote location for cooling does is long and may allow the resin to react loner than desired. 
     Therefore, there is a need for improved methods for resist patterning on a substrate. 
     SUMMARY 
     A method and apparatus for performing post-exposure bake cooling operations is described herein. The method begins by post exposure baking a substrate disposed on heated substrate support in a process chamber, the process chamber having a showerhead. The heated substrate support is moved to increase a distance between the heated substrate support and a cooled plate of the showerhead. The substrate is separated from the heated substrate support using a substrate lifting device. The substrate is moved into a close proximity to the cooled showerhead. The substrate is cooled until the substrate is less than about 70 degrees Celsius. The substrate is spaced away from the cooled showerhead using the substrate lifting device and aligning the substrate with a substrate transfer passage of the processing chamber for removal by a robot. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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, may admit to other equally effective embodiments. 
         FIG.  1    illustrates a schematic cross-sectional view of a processing chamber, according to one embodiment. 
         FIG.  2    is a flow diagram of a method of processing a substrate within the processing chamber of  FIG.  1   . 
         FIGS.  3 A to  3 D  illustrate various pedestal and substrate positions suitable for use during a cooling operation of the method depicted in  FIG.  2   . 
         FIG.  4    is a flow diagram of one example of the cooling operation of the method depicted in  FIG.  2    utilizing the pedestal and substrate positions illustrated in  FIGS.  3 A to  3 D . 
     
    
    
     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 
     The present disclosure is generally directed towards apparatus and methods for use during post-exposure bake of a semiconductor substrate. Methods and apparatus disclosed herein assist in improving exposure resolution in a photolithography process for semiconductor processing applications by reducing the time needed to cool the substrate. The apparatus described herein enable in-situ rapid cooling of the substrate after an electric field guided bake of the resist layer on the substrate. The method and apparatus enables the rapid (typically in less than 30 seconds) cooling of a substrate from temperatures of up to about 400 degrees Celsius (° C.) to temperatures at or below about 70° C. 
     A “substrate” or “substrate surface,” as described herein, generally refers to any substrate surface upon which processing is performed. Processing includes deposition, etching, patterning and other methods utilized during semiconductor processing. A substrate or substrate surface which may be processed also includes dielectric materials such as silicon dioxide, silicon nitride, organosilicates, and carbon doped silicon oxide or nitride materials. In certain embodiments, the substrate or substrate surface includes photoresist materials, hardmask materials, or other films or layers utilized in the patterning of a substrate. The substrate itself is not limited to any particular size or shape. Although the embodiments described herein are made with generally made with reference to a round 200 mm or 300 mm substrate, other shapes, such as polygonal, squared, rectangular, curved, or otherwise non-circular substrates may be utilized according to the embodiments described herein. 
       FIG.  1    illustrates a schematic cross-sectional view of a process chamber  100 , according to one embodiment. The process chamber  100  is configured to perform field guided post-exposure bake operations on a substrate  150  with a photoresist or chemically modified resist layer disposed thereon. However, it is contemplated that other suitably configured process chambers may benefit from the embodiments described herein. 
     The process chamber  100  includes an upper chamber body  116  coupled to the lower chamber body  120 . The upper chamber body  116  and the lower chamber body  120  are coupled together to define at least a portion of the process volume  170 . A substrate support  130  is disposed in the process volume  170  and utilized to support the substrate  150  thereon during processing. A showerhead assembly  110  is disposed on top of the upper chamber body  116  above the substrate support  130 . The showerhead assembly  110  includes one or more cooled plates configured to allow process of other gas to flow therethrough. In the example of  FIG.  1   , the showerhead assembly  110  includes a plurality of stacked plates, one of which is cooled using temperate control techniques, such as flowing heat transfer fluid therethrough and/or via thermo-electric devices. 
     The lower chamber body  120  includes at least one substrate transfer passage  160  disposed therethrough. The transfer passage  160  may have a slit valve door configured to provide access to the process volume  170  by a transfer robot moving the substrate  150  into and out of the process volume  170 . A pumping liner may be disposed radially inward of the lower chamber body  120 . The pumping liner includes a plurality of openings connecting an exhaust plenum and the process volume  170  such that gas is removed via the exhaust plenum by a pump. 
     The showerhead assembly  110  includes at least one cooled plate disposed closest to the substrate support  130 . The substrate  150  may be moved immediately adjacent the cooled plate to assist regulating, for example cooling, the substrate after the post bake process. 
     In the example depicted in  FIG.  1   , the showerhead assembly  110  includes a mixing block  102 , a gas box  103 , a gas diffuser  104 , a faceplate  106 , an insulator  108 , and a cooled ion blocking plate  114 . Each of the mixing block  102 , the gas box  103 , the gas diffuser  104 , the faceplate  106 , and the ion blocking plate  114  have a plurality of holes disposed therethrough to enable process gases to be flown through the plate stack. The ion blocking plate  114  has a bottom surface  141  facing the process volume  170 . Although in the example depicted in  FIG.  1    the ion blocking plate  104  is cooled and immediately adjacent the substrate support  130 , in other showerheads, other types of cooled plates may be disposed closest the substrate support  130 . 
     The mixing block  102  may serve as an RF electrode and/or a gas manifold. Process gasses are provided to the mixing block  102  from a gas source  136 . The mixing block  102  may be electrically coupled to the gas diffuser  104  and the faceplate  106  that serve to redirect flow of the source gases so that gas flow is uniform. It should be noted that all of the diffusers or screens herein may be characterized as electrodes, as any such diffusers or screens may be coupled to a particular electrical potential. The insulator  108  electrically insulates the mixing block  102  and the faceplate  106  from the ion blocking plate  114 . 
     Surfaces of the faceplate  106 , the ion blocking plate  114  and the insulator  108  define a plasma generation region  111  where a first plasma is created when the gas from the gas source  136  is present and energy is provided at the faceplate  106  through the mixing block  102 . The faceplate  106  and the ion blocking plate  114  may be held at different voltage potentials to control the ion density of the plasma formed therebetween. The ion blocking plate  114  filters the plasma as it passes through to reduce the concentration of ions. 
     Portions of the ion blocking plate  114  which are exposed directly to plasma may be coated with ceramic (e.g., alumina or yttria) while surfaces that are not exposed directly to plasma may also be coated with ceramic, and are advantageously at least coated with a passivating layer for chemical resistance to reactive gases and activated species. 
     The ion blocking plate  114  constitutes the bottom plate of the plate stack as described herein. The ion blocking plate  114  is a showerhead configured to prevent plasma from traveling back up the plate stack from the process volume  170 . The ion blocking plate  114  is also configured to reduce the number of ions within a plasma passing through the ion blocking plate  114  and into the process volume  170 . The bottom surface  141  of the ion blocking plate  114  faces a top surface  132  of the substrate support  130  disposed in the process volume  170 . 
     The ion blocking plate  114  serves as a selectivity modulation device (SMD) which performs ion filtering. A controlled amount of radicals pass through the ion blocking plate  114  while blocking plasma from entering the processing volume  170 . The ion blocking plate  114  is cooled. The ion blocking plate  114  has integrated channels  192  connected with a source of coolant  190 . The integrated channels  192  may spiral through ion blocking plate  114 . The source of coolant  190  can provide deionized water, glycol, an inert, high-performance, fluorinated heat transfer fluid, or other fluid suitable as a coolant. Alternately, or additionally, the ion blocking plate  114  may have thermo-electric cooling devices, such as a Peltier cooling elements and the like. The thermo-electric cooling devices may be electrically driven to provide cooling (or even heating) to the ion blocking plate  114 . 
     The cooling of the ion blocking plate  114  (or other cooled plate of the showerhead assembly  110  closest the substrate support  130 ) control ions recombination efficiency by keeping the ion blocking plate  114  at a constant temperature. The plasma in the plasma cavity above the ion blocking plate  114  causes the temperature of the ion blocking plate  114  to increase. This increase in temperature causes variation in recombination efficiency. Temperature control of the ion blocking plate  114  substantially eliminates the variation. 
     While being exposed to the low ion density plasma, the substrate  150  sits on the substrate support  130  portion of a substrate support assembly  126 . The substrate support  130  is a heated pedestal configured to control a temperature of the substrate. The substrate support assembly  126  further includes a shaft  128  and bellows connecting the substrate support assembly  126  to the lower chamber body  120 . The bellows form a seal between the process volume  170  and an outside environment. One or more backside gas sources may be coupled to the substrate support assembly  126  to supply backside gas to the top surface  132  of the substrate support  130 . 
     A power source and motion apparatus are also coupled to the substrate support assembly  126 . The power source may be an AC or a DC power source. The power source is configured to supply power to the motion apparatus  148  and/or heating devices  129  within the substrate support  130 . The motion apparatus  148  is configured to enable movement of the substrate support assembly  126 , such as raising or lowering the substrate support assembly  126 , rotating the substrate support assembly about a central axis, or tilting the substrate support  130 . 
     The substrate support assembly  126  additionally has a substrate lifting device  137 . The substrate lifting device  137  is coupled to a movement assembly  135  for raising and lowering the substrate lifting device  137 . The substrate lifting device  137  is raised to an upper position for accepting the substrate  150  from the transfer robot. The substrate lifting device  137  is lowered to place the substrate  150  onto the top surface  132  of the substrate support  130  for processing. The substrate lifting device  137  may be lift pins, a hoop, edge support ring, or any suitable device for accepting the substrate  150  from a robot blade and moving the substrate from the top surface  132  of the substrate support  130  to a raised position above the substrate support  130 . In one example, the substrate lifting device  137  is a plurality of lift pins. The lift pins can move to an elevated position to pick the substrate  150  and balance the substrate  150  thereon the pins. The lift pins can move below top surface  132  of the substrate support  130  into lift pin holes while the substrate  150  is engaged with the heated substrate support  130  during processing. In another example, the substrate lifting device  137  is a hoop having and openings for the robot blade. The hoop can move to an elevated position to pick the substrate  150  and hold the substrate  150  along its edge. The hoop can move into a groove in the top surface  132  of the substrate support  130  while the substrate  150  is engaged with the heated substrate support  130  during processing. 
     The above-described processing chamber  100  can be controlled by a processor based system controller such a controller  178 . For example, the controller  178  may be configured to control flow of various precursor gases via the gas sources  136  and coordinate plasma generation and flows within the processing chamber  100 . The controller  178  may also be configured to control all aspects of electric field generation within the processing chamber  100  by modulating and controlling application of voltages to one or more of the components of the showerhead assembly  110  and the substrate support assembly  126  to generate an electric field within the process volume  170 . The controller  178  further operates to control various stages of a substrate process sequence. 
     The controller  178  includes a programmable central processing unit (CPU)  172  that is operable with a memory  174  and a mass storage device, an input control unit, and a display unit (not shown), such as power supplies, clocks, cache, input/output (I/O) circuits, and the like, coupled to the various components of the processing chamber  100  to facilitate control of the substrate processing. The controller  178  also includes hardware for monitoring substrate processing through sensors in the processing chamber  100 , including sensors monitoring flow, RF power, voltage potential and the like. Other sensors that measure system parameters such as substrate temperature, chamber atmosphere pressure and the like, may also provide information to the controller  178 . 
     To facilitate control of the processing chamber  100  and associated plasma and electric field formation processes, the CPU  172  may be one of any form of general purpose computer processor that can be used in an industrial setting, such as a programmable logic controller (PLC), for controlling various chambers and sub-processors. The memory  174  is coupled to the CPU  172  and the memory  174  is non-transitory and may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk drive, hard disk, or any other form of digital storage, local or remote. Support circuits  176  are coupled to the CPU  172  for supporting the processor in a conventional manner. The plasma and electric field formation and other processes are generally stored in the memory  174 , typically as a software routine. The software routine may also be stored and/or executed by a second CPU (not shown) that is remotely located from the hardware being controlled by the CPU  172 . 
     The memory  174  is in the form of computer-readable storage media that contains instructions, that when executed by the CPU  172 , facilitates the operation of the processing chamber  100 . The instructions in the memory  174  are in the form of a program product such as a program that implements the method of the present disclosure. The program code may conform to any one of a number of different programming languages. In one example, the disclosure may be implemented as a program product stored on computer-readable storage media for use with a computer system. The program(s) of the program product define functions of the embodiments (including the methods described herein). 
     In certain embodiments, the program(s) embody machine learning capabilities. Various data features include process parameters such as processing times, temperatures, pressures, voltages, polarities, powers, gas species, precursor flow rates, and the like. Relationships between the features are identified and defined to enable analysis by a machine learning algorithm to ingest data and adapt processes being performed by the processing chamber  100 . The machine learning algorithms may employ supervised learning or unsupervised learning techniques. Examples of machine learning algorithms embodied by the program include, but are not limited to, linear regression, logistic regression, decision tree, state vector machine, neural network, naïve Bayes, k-nearest neighbors, K-Means, random forest, dimensionality reduction algorithms, and gradient boosting algorithms, among others. In one example, the machine learning algorithm is utilized to modulate RF power and precursor gas flow to form a plasma and then facilitate maintenance of a low ion density plasma which includes a greater concentration of radicals than ions. The formation of charges species in this manner may be refined and improved by identifying constituents of the charged species cloud (e.g. radicals and/or ions) and modifying chamber process or apparatus characteristics to form and maintain a charged species cloud which exhibits desirable characteristics as an electric field coupling medium between the ion blocking plate  114  and the substrate support  130 . 
     Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory devices within a computer such as CD-ROM disks readable by a CD-ROM drive, flash memory, ROM chips or any type of solid-state non-volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored. Such computer-readable storage media, when carrying computer-readable instructions that direct the functions of the methods described herein, are embodiments of the present disclosure. 
       FIG.  2    is a flow diagram of a method  200  of processing a substrate within the processing chamber of  FIG.  1   , according to one embodiment. The substrate  150  is introduced into the processing volume  170  of the processing chamber  100  on the robot blade. The cooled ion blocking plate  114  (or other cooled plate of the showerhead assembly  110  closest the substrate support  130 ) helps the substrate  150  to not overheat when the substrate  150  is coming into the processing chamber  100  and still sitting on the robot blade. This is important advantage to reduce or eliminate completely field on delay, i.e., when the substrate  150  is engaging with the substrate support  130 , the AC or DC or both fields is applied when the substrate  150  reaches the desirable temperature but still below the baking temperature. The method  200  includes flowing a first gas into a first plasma formation region, such as the plasma generation region  111 , during an operation  202 . After flowing the first gas into the first plasma formation region, a first plasma is formed within the plasma generation region  111  during another operation  204 . The plasma has a first ion density. The first ion density plasma is a high ion density plasma, such that the ion density within the first plasma is about 10 5  ions/cm 3  to about 10 10  ions/cm 3 . 
     During operation  206 , the ions within the first plasma are reduced by the ion blocking plate  114  to form the second plasma. The second plasma may optionally be mixed with a second gas during another operation. During the operation  208 , the second gas is mixed with the second plasma. The second plasma has a second ion density lower than the first ion density of the first plasma. The second plasma is described as a low ion density plasma and has an ion concentration of about 10 3  ions/cm 3  to about 10 7  ions/cm 3 . As the second plasma passes through the ion blocking plate  114  at operation  210 , ions are removed to leave a greater ratio of radicals to ions within the second plasma. The second plasma is heated to a temperature between about 120° C. to about 250° C. 
     At operation  210 , the second plasma is flowed through the apertures of the ion blocking plate  114  and into the process volume  170  between ion blocking plate  114  and the substrate support  130 /substrate  150 . The voltage differential between the ion blocking plate  114  and the substrate support  130  is about 0 V to about 200 V, such as about 10 V to about 150 V. The voltage source  260  may further include AC/DC waveform control, such that a DC voltage may be applied or an AC voltage with a frequency of less than or equal to about 7.5 kHz, such as an AC voltage of about 0 kHz to about 7.5 kHz. In some embodiments, the AC waveform may have a DC offset, such that the signal peaks are not centered about 0 V. The pressure within the process volume  170  is about 0.5 Torr to about 10 Torr, such as about 0.5 Torr to about 8 Torr, such as about 1 Torr to about 5 Torr. 
     The second plasma is a charged species cloud while within the process volume  170 , such that the concentration of ions within the second plasma is reduced while passing through the ion blocking plate  114  and into the process volume  170 . The radicals within the charged species cloud are controlled by the electric field formed between the ion blocking plate  114  and the substrate support  130 . The electric field assists in controlling the ion density within the second plasma, such that the ion or electron density is about 10 4  ions/cm 3  to about 10 6  ions/cm 3 . The charged ions within the charges species cloud have an ion temperature of less than about 1 eV each and therefore have reduced impact on the photoresist disposed on the substrate  150  while also forming a dark plasma above the substrate support  130 . The dark plasma is beneficial in that the photoresist is does not undergo a concurrent exposure process during the post exposure bake operation. Either concurrently with or immediately after the second plasma is flowed into the process volume  170  to form the charged species cloud, the substrate on the top surface  132  is baked at a temperature of about 75° C. to about 400° C., such as about 100° C. to about 250° C. during operation  210 . 
     After baking at operation  212 , the substrate  150  is rapidly cooled to temperatures below about 70° C. to slow or mitigate the continued baking from negatively impacting the photoresist. For example, the substrate  150  may be cooled to a temperature below about 70° C. In another example, the substrate  150  is cooled to a temperature below about 70° C. in 30 seconds or less. By performing cooling in-situ the process chamber, cooling can be performed much faster as compared to conventional processes where the substrate  150  transported by a robot to a cooling location outside of the process chamber  100 . Rapidly cooling the substrate  150  is enhanced by removing the substrate from the heated substrate support  130  while remaining in the process chamber  100 . A method and apparatus for rapidly cooling the substrate  150  is disclosed below with respect to  FIGS.  3 A- 3 D  and  FIG.  4   . 
       FIGS.  3 A to  3 D  illustrate various pedestal and substrate positions suitable for cooling the substrate in the processing chamber during the cooling operation  212  of the method  200  illustrated in  FIG.  2   .  FIG.  4    is a flow diagram of one example of the cooling operation  212 , which can also alternatively be used with other processes in addition to the method  200  described above where in-situ substrate cooling is desirable. The cooling operation  212  in  FIG.  4    is described with reference to the pedestal and substrate positions illustrated in  FIGS.  3 A to  3 D . 
       FIG.  3 A  illustrates the substrate support  130  in a down position (shown by imaginary reference line  330 ) and the substrate lifting device  137  in a load/unloading position (shown by imaginary reference line  320 ). The load/unloading position of the substrate lifting device  137  is aligned with the transfer passage  160  to allow a robot, not shown, to pick and place the substrate on the substrate lifting device  137  through the transfer passage  160 . The substrate  150 , while on the substrate lifting device  137 , is elevated a first distance  362  above the top surface  132  of the substrate support  130  by the substrate lifting device  137 . 
       FIG.  3 A  also the substrate  150  elevated a first distance  362  above the top surface  132  of the substrate support  130  by the substrate lifting device  137 . The substrate  150  is disposed below the bottom surface  141  (shown by imaginary reference line  310 ) of the ion blocking plate  114  (or other cool plate of the showerhead stack disposed closest the substrate support  130 ) by a second distance  364 . 
       FIG.  3 B  illustrates the substrate support  130  in an up position, i.e., a processing position (as shown by imaginary reference line  332 ), and the substrate lifting device  137  is in a retracted position such that the substrate  150  is resting on the top surface  132  of the substrate support  130 . The substrate  150  is in close proximity to the ion blocking plate  114  in a position for baking. A third distance  366  between the bottom surface  141  of the ion blocking plate  114  and the top surface  132  of the substrate support  130  is about 2 mm to about 20 mm, such as about 5 mm to about 15 mm, such as about 10 mm to about 15 mm. 
       FIG.  3 C  illustrates the substrate support  130  in the down position (as shown by imaginary reference line  330 ) and the substrate lifting device  137  is in a post bake cooling position, i.e., nearest the bottom surface  141  of the ion blocking plate  114 . The substrate  150  is elevated a fourth distance  372  above the top surface  132  of the substrate support  130  by the substrate lifting device  137 . The substrate  150  is a fourth distance  368  from the bottom surface  141  of the ion blocking plate  114 . The fourth distance  368  is suitable for cooling the substrate with the cooling mechanisms provided by the ion blocking plate  114  (or other cooled plate of the showerhead assembly  110  closest the substrate support  130 ). In one example, the fourth distance  368  of the substrate  150  from the ion blocking plate  114  is about 2 mm or less, such as about 1 mm. 
       FIG.  3 D  illustrates the substrate support  130  back in the down position  330  with the substrate lifting device  137  in the load/unloading position  320  for moving the substrate  150  out the transfer passage  160  with the robot. 
     The cooling operation  212  depicted in flow diagram of  FIG.  4    begins after the completion of operation  210  of method  200  or other method of baking the substrate (or generally when the substrate needs in-situ cooling before, during or after another process performed in the process chamber  100  or other chamber). Prior to operation  202  of the method  200 , the substrate support  130  is in the down position shown by reference line  330  and the substrate lifting device  137  is in the load/unloading position shown by reference line  320 , as depicted in  FIG.  3 A . During operations  202 - 210  of method  200 , the substrate support  130  is in the processing position shown by reference line  332  with the substrate lifting device  137  retracted such that the substrate  150  is resting on the top surface  132  of the substrate support  130 , as depicted in  FIG.  3 B . After completion of operation  210 , the substrate  150  is cooled at operation  212 . 
     At operation  212 , the heated substrate support  130  is moved to increase the gap between the heated substrate support and the cooled ion blocking plate  114  (or other cooled plate of the showerhead assembly  110  closest the substrate support  130 ). The heated substrate support  130 , as consequently the substrate  150  disposed thereon, may be at a temperature above 70° C., such as up to about 400° C. The substrate  150  is at a temperature above 70° C. during the baking operation  210  to assist the chemical reaction that occurs during the exposure. 
     At operation  420 , the heated substrate support  130  is spaced from the substrate  150 . In one example, the substrate lifting device  137  is extended relative to the heated substrate support  130  to space the substrate  150  away from the heated substrate support  130 . Spacing the substrate may, in some examples, move the substrate  150  toward the cooled lowest plate of the showerhead stack, in this case the ion blocking plate  114 . In this manner, heat transfer to the substrate  150  from the substrate support  130  is significantly reduced. 
     At operation  430 , the substrate  150  is moved into close proximity the cooled showerhead, while optionally increasing gas flow through the cooled ion blocking plate  114 . In one example, the substrate  150  is moved to within less than about 2 mm from the cooled showerhead. The substrate  150  is closer to the ion blocking plate  114  for the cooling operation than the baking operation. In one example, the substrate is 5 times closer to the ion blocking plate  114  during the cooling operation than during the baking operation. The temperature of the cooled ion blocking plate  114  may be controlled by cooling fluid and/or thermo-electric devices for cooling the substrate  150 . Additionally, gas or even a cooled gas, may be flowed through the showerhead assembly  110  for assisting the cooling the substrate  150 . The pressure and or flow of the gas may be regulated to effect faster cooling of the substrate  150  in the processing chamber  100 . In one example, the gas utilized to cool the substrate is different that the gas or gas mixture provided during baking. In one example, the gas utilized to cool the substrate is hydrogen, nitrogen, argon, helium or an inert gas, which can be introduced under pressure through the cooled ion blocking plate  114  to assist cooling the substrate  150 . 
     At operation  440 , the substrate  150  is cooled to a temperature below about 70° C., such as between about 50° C. and about 70° C. The substrate  150  is cooled by the cooled ion blocking plate  114  while being elevated away from the heated substrate support  130 , which reduces the time needed to cool the substrate  150  from the baking temperatures at operation  210  to a temperature less than about 70° C. The combination of spacing and proximity to the cooled plate, along with the present of a cooling gas speeds up cooling of the substrate  150  compared to conventional techniques. In one embodiment, the substrate is cooled to about 40° C. in about 20 seconds. The substrate  150  may monitored by a temperature sensor or by recipe for completing this operation. 
     At operation  450 , the substrate  150  is moved away from the cooled showerhead using the substrate lifting device  137  to the load/unloading position  320  depicted in  FIG.  3 A  which aligns with the transfer passage  160  of the processing chamber  100  for removal by the transfer robot. 
     Described herein are apparatus and methods for forming a low ion density plasma above a substrate within a process volume for baking a substrate and in-situ rapid cooling of the substrate for stopping the baking process. Advantageously, the baking process can be quickly stopped to ensure film integrity. Additionally, the apparatus and method eliminates concern about substrate transfer time and the need for a cooling pedestal disposed outside of the process chamber. 
     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.