Device to increase deposition uniformity in spatial ALD processing chamber

Susceptor assemblies comprising a susceptor with a top surface with a plurality of recesses and a bottom surface are described. A heater is positioned below the susceptor to heat the susceptor. A shield is positioned between the bottom surface of the susceptor and the heater. The shield increases deposition uniformity across the susceptor.

TECHNICAL FIELD

The present disclosure relates generally to apparatus for depositing thin films. In particular, the disclosure relates to apparatus for depositing thin films in a spatial atomic layer deposition batch processing chamber.

BACKGROUND

Wafer temperature uniformity is important in atomic layer deposition (ALD) processes. Deposition uniformity in spatial ALD batch processes reactors can be challenging where the wafer is positioned on a susceptor moving above an infrared heating system. Traditionally, for improvement of temperature uniformity, multi-zone heating is used. However, the systems used for improved temperature uniformity are complex and the cost is proportional to the number of heating zones. Moreover, for spatial ALD systems with rotating susceptors it is very difficult to achieve good temperature distribution in the tangential direction and, as a result, leading and trailing edge temperatures are very difficult to homogenize with the rest of the wafer surface resulting in non-uniform deposition.

Therefore, there is a need in the art for apparatus and methods to increase deposition uniformity in batch processing chambers.

SUMMARY

One or more embodiments of the disclosure are directed to susceptor assemblies comprising a susceptor with a top surface and a bottom surface. The top surface has a plurality of recesses formed therein. The recesses are sized to support a substrate during processing. A heater is positioned below the susceptor to heat the susceptor. A shield is positioned between the bottom surface of the susceptor and the heater. The shield increases deposition uniformity across the susceptor.

Additional embodiments of the disclosure are directed to susceptor assemblies comprising a susceptor with a top surface and a bottom surface. The top surface has a plurality of recesses formed therein. The recesses are sized to support a substrate during processing. A heater is positioned below the susceptor to heat the susceptor. A shield is positioned between the bottom surface of the susceptor and the heater. The shield comprises a plurality of shield segments. Each shield segment is positioned in a region between the recesses and increasing deposition uniformity across the susceptor and is contoured to have a shape similar to a shape of the recesses and cover more of a leading edge of a recess than a trailing edge of an adjacent recess. Each shield segment includes a plurality of openings therethrough. A plurality of suspension rods connects the susceptor and the shield. The suspension rods pass through the plurality of openings in the shield segments to support the shield segments and maintain a gap between the shield segments and the susceptor.

Further embodiments of the disclosure are directed to susceptor assemblies comprising a susceptor with a top surface and a bottom surface. The top surface has a plurality of recesses formed therein. The recesses are sized to support a substrate during processing. A heater is positioned below the susceptor to heat the susceptor. A shield is positioned between the bottom surface of the susceptor and the heater. The shield increases deposition uniformity across the susceptor. The shield has a ring shape with an inner edge and an outer edge. The inner edge is closer to a center of the susceptor than the outer edge. The shield includes a plurality of protrusions extending inwardly from the inner edge, each protrusion having an opening therethrough. The distance from the inner edge of the shield to the outer edge of the shield covers at least about ⅔ of a width of the recess. A plurality of suspension rods connects to the susceptor and supports the shield and maintains a gap between the shield and the susceptor. Each of the suspension rods pass through an opening in the shield.

DETAILED DESCRIPTION

Some embodiments of the disclosure are directed to processes of depositing a spacer material using a batch processing chamber, also referred to as a spatial processing chamber.FIG. 1shows a cross-section of a processing chamber100including a gas distribution assembly120, also referred to as injectors or an injector assembly, and a susceptor assembly140. The gas distribution assembly120is any type of gas delivery device used in a processing chamber. The gas distribution assembly120includes a front surface121which faces the susceptor assembly140. The front surface121can have any number or variety of openings to deliver a flow of gases toward the susceptor assembly140. The gas distribution assembly120also includes an outer edge124which in the embodiments shown, is substantially round.

The specific type of gas distribution assembly120used can vary depending on the particular process being used. Embodiments of the disclosure can be used with any type of processing system where the gap between the susceptor and the gas distribution assembly is controlled. While various types of gas distribution assemblies can be employed (e.g., showerheads), embodiments of the disclosure may be particularly useful with spatial gas distribution assemblies which have a plurality of substantially parallel gas channels. As used in this specification and the appended claims, the term “substantially parallel” means that the elongate axis of the gas channels extend in the same general direction. There can be slight imperfections in the parallelism of the gas channels. In a binary reaction, the plurality of substantially parallel gas channels can include at least one first reactive gas A channel, at least one second reactive gas B channel, at least one purge gas P channel and/or at least one vacuum V channel. The gases flowing from the first reactive gas A channel(s), the second reactive gas B channel(s) and the purge gas P channel(s) are directed toward the top surface of the wafer. Some of the gas flow moves horizontally across the surface of the wafer and out of the process region through the purge gas P channel(s). A substrate moving from one end of the gas distribution assembly to the other end will be exposed to each of the process gases in turn, forming a layer on the substrate surface.

In some embodiments, the gas distribution assembly120is a rigid stationary body made of a single injector unit. In one or more embodiments, the gas distribution assembly120is made up of a plurality of individual sectors (e.g., injector units122), as shown inFIG. 2. Either a single piece body or a multi-sector body can be used with the various embodiments of the disclosure described.

A susceptor assembly140is positioned beneath the gas distribution assembly120. The susceptor assembly140includes a top surface141and at least one recess142in the top surface141. The susceptor assembly140also has a bottom surface143and an edge144. The recess142can be any suitable shape and size depending on the shape and size of the substrates60being processed. In the embodiment shown inFIG. 1, the recess142has a flat bottom to support the bottom of the wafer; however, the bottom of the recess can vary. In some embodiments, the recess has step regions around the outer peripheral edge of the recess which are sized to support the outer peripheral edge of the wafer. The amount of the outer peripheral edge of the wafer that is supported by the steps can vary depending on, for example, the thickness of the wafer and the presence of features already present on the back side of the wafer.

In some embodiments, as shown inFIG. 1, the recess142in the top surface141of the susceptor assembly140is sized so that a substrate60supported in the recess142has a top surface61substantially coplanar with the top surface141of the susceptor140. As used in this specification and the appended claims, the term “substantially coplanar” means that the top surface of the wafer and the top surface of the susceptor assembly are coplanar within ±0.2 mm. In some embodiments, the top surfaces are coplanar within 0.5 mm, ±0.4 mm, ±0.35 mm, ±0.30 mm, ±0.25 mm, ±0.20 mm, ±0.15 mm, ±0.10 mm or ±0.05 mm.

The susceptor assembly140ofFIG. 1includes a support post160which is capable of lifting, lowering and rotating the susceptor assembly140. The susceptor assembly may include a heater, or gas lines, or electrical components within the center of the support post160. The support post160may be the primary means of increasing or decreasing the gap between the susceptor assembly140and the gas distribution assembly120, moving the susceptor assembly140into proper position. The susceptor assembly140may also include fine tuning actuators162which can make micro-adjustments to susceptor assembly140to create a predetermined gap170between the susceptor assembly140and the gas distribution assembly120. In some embodiments, the heater is not part of the susceptor assembly. In some embodiments, the heater is a separate component from the susceptor assembly. In some embodiments, the heater is separate from the susceptor assembly and is configured to move along with the susceptor assembly to maintain a fixed distance between the susceptor assembly and the heater.

In some embodiments, the gap170distance is in the range of about 0.1 mm to about 5.0 mm, or in the range of about 0.1 mm to about 3.0 mm, or in the range of about 0.1 mm to about 2.0 mm, or in the range of about 0.2 mm to about 1.8 mm, or in the range of about 0.3 mm to about 1.7 mm, or in the range of about 0.4 mm to about 1.6 mm, or in the range of about 0.5 mm to about 1.5 mm, or in the range of about 0.6 mm to about 1.4 mm, or in the range of about 0.7 mm to about 1.3 mm, or in the range of about 0.8 mm to about 1.2 mm, or in the range of about 0.9 mm to about 1.1 mm, or about 1 mm.

The processing chamber100shown in the Figures is a carousel-type chamber in which the susceptor assembly140can hold a plurality of substrates60. As shown inFIG. 2, the gas distribution assembly120may include a plurality of separate injector units122, each injector unit122being capable of depositing a film on the wafer, as the wafer is moved beneath the injector unit. Two pie-shaped injector units122are shown positioned on approximately opposite sides of and above the susceptor assembly140. This number of injector units122is shown for illustrative purposes only. It will be understood that more or less injector units122can be included. In some embodiments, there are a sufficient number of pie-shaped injector units122to form a shape conforming to the shape of the susceptor assembly140. In some embodiments, each of the individual pie-shaped injector units122may be independently moved, removed and/or replaced without affecting any of the other injector units122. For example, one segment may be raised to permit a robot to access the region between the susceptor assembly140and gas distribution assembly120to load/unload substrates60.

Processing chambers having multiple gas injectors can be used to process multiple wafers simultaneously so that the wafers experience the same process flow. For example, as shown inFIG. 3, the processing chamber100has four gas injector assemblies and four substrates60. At the outset of processing, the substrates60can be positioned between the injector assemblies30. Rotating17the susceptor assembly140by 45° will result in each substrate60which is between gas distribution assemblies120to be moved to an gas distribution assembly120for film deposition, as illustrated by the dotted circle under the gas distribution assemblies120. An additional 45° rotation would move the substrates60away from the injector assemblies30. The number of substrates60and gas distribution assemblies120can be the same or different. In some embodiments, there are the same numbers of wafers being processed as there are gas distribution assemblies. In one or more embodiments, the number of wafers being processed are fraction of or an integer multiple of the number of gas distribution assemblies. For example, if there are four gas distribution assemblies, there are 4× wafers being processed, where x is an integer value greater than or equal to one. In an exemplary embodiment, the gas distribution assembly120includes eight process regions separated by gas curtains and the susceptor assembly140can hold six wafers.

The processing chamber100shown inFIG. 3is merely representative of one possible configuration and should not be taken as limiting the scope of the disclosure. Here, the processing chamber100includes a plurality of gas distribution assemblies120. In the embodiment shown, there are four gas distribution assemblies (also called injector assemblies30) evenly spaced about the processing chamber100. The processing chamber100shown is octagonal; however, those skilled in the art will understand that this is one possible shape and should not be taken as limiting the scope of the disclosure. The gas distribution assemblies120shown are trapezoidal, but can be a single circular component or made up of a plurality of pie-shaped segments, like that shown inFIG. 2.

The embodiment shown inFIG. 3includes a load lock chamber180, or an auxiliary chamber like a buffer station. This chamber180is connected to a side of the processing chamber100to allow, for example the substrates (also referred to as substrates60) to be loaded/unloaded from the chamber100. A wafer robot may be positioned in the chamber180to move the substrate onto the susceptor.

Rotation of the carousel (e.g., the susceptor assembly140) can be continuous or intermittent (discontinuous). In continuous processing, the wafers are constantly rotating so that they are exposed to each of the injectors in turn. In discontinuous processing, the wafers can be moved to the injector region and stopped, and then to the region84between the injectors and stopped. For example, the carousel can rotate so that the wafers move from an inter-injector region across the injector (or stop adjacent the injector) and on to the next inter-injector region where the carousel can pause again. Pausing between the injectors may provide time for additional processing steps between each layer deposition (e.g., exposure to plasma).

FIG. 4shows a sector or portion of a gas distribution assembly220, which may be referred to as an injector unit122. The injector units122can be used individually or in combination with other injector units. For example, as shown inFIG. 5, four of the injector units122ofFIG. 4are combined to form a single gas distribution assembly220. (The lines separating the four injector units are not shown for clarity.) While the injector unit122ofFIG. 4has both a first reactive gas port125and a second gas port135in addition to purge gas ports155and vacuum ports145, an injector unit122does not need all of these components.

Referring to bothFIGS. 4 and 5, a gas distribution assembly220in accordance with one or more embodiment may comprise a plurality of sectors (or injector units122) with each sector being identical or different. The gas distribution assembly220is positioned within the processing chamber and comprises a plurality of elongate gas ports125,135,145in a front surface121of the gas distribution assembly220. The plurality of elongate gas ports125,135,145,155extend from an area adjacent the inner peripheral edge123toward an area adjacent the outer peripheral edge124of the gas distribution assembly220. The plurality of gas ports shown include a first reactive gas port125, a second gas port135, a vacuum port145which surrounds each of the first reactive gas ports and the second reactive gas ports and a purge gas port155.

With reference to the embodiments shown inFIG. 4 or 5, when stating that the ports extend from at least about an inner peripheral region to at least about an outer peripheral region, however, the ports can extend more than just radially from inner to outer regions. The ports can extend tangentially as vacuum port145surrounds reactive gas port125and reactive gas port135. In the embodiment shown inFIGS. 4 and 5, the wedge shaped reactive gas ports125,135are surrounded on all edges, including adjacent the inner peripheral region and outer peripheral region, by a vacuum port145.

Referring toFIG. 4, as a substrate moves along path127, each portion of the substrate surface is exposed to the various reactive gases. To follow the path127, the substrate will be exposed to, or “see”, a purge gas port155, a vacuum port145, a first reactive gas port125, a vacuum port145, a purge gas port155, a vacuum port145, a second gas port135and a vacuum port145. Thus, at the end of the path127shown inFIG. 4, the substrate has been exposed to the first reactive gas125and the second reactive gas135to form a layer. The injector unit122shown makes a quarter circle but could be larger or smaller. The gas distribution assembly220shown inFIG. 5can be considered a combination of four of the injector units122ofFIG. 4connected in series.

The injector unit122ofFIG. 4shows a gas curtain150that separates the reactive gases. The term “gas curtain” is used to describe any combination of gas flows or vacuum that separate reactive gases from mixing. The gas curtain150shown inFIG. 4comprises the portion of the vacuum port145next to the first reactive gas port125, the purge gas port155in the middle and a portion of the vacuum port145next to the second gas port135. This combination of gas flow and vacuum can be used to prevent or minimize gas phase reactions of the first reactive gas and the second reactive gas.

Referring toFIG. 5, the combination of gas flows and vacuum from the gas distribution assembly220form a separation into a plurality of process regions250. The process regions are roughly defined around the individual gas ports125,135with the gas curtain150between250. The embodiment shown inFIG. 5makes up eight separate process regions250with eight separate gas curtains150between. A processing chamber can have at least two process region. In some embodiments, there are at least three, four, five, six, seven, eight, nine, 10, 11 or 12 process regions.

During processing a substrate may be exposed to more than one process region250at any given time. However, the portions that are exposed to the different process regions will have a gas curtain separating the two. For example, if the leading edge of a substrate enters a process region including the second gas port135, a middle portion of the substrate will be under a gas curtain150and the trailing edge of the substrate will be in a process region including the first reactive gas port125.

A factory interface280, which can be, for example, a load lock chamber, is shown connected to the processing chamber100. A substrate60is shown superimposed over the gas distribution assembly220to provide a frame of reference. The substrate60may often sit on a susceptor assembly to be held near the front surface121of the gas distribution plate120. The substrate60is loaded via the factory interface280into the processing chamber100onto a substrate support or susceptor assembly (seeFIG. 3). The substrate60can be shown positioned within a process region because the substrate is located adjacent the first reactive gas port125and between two gas curtains150a,150b. Rotating the substrate60along path127will move the substrate counter-clockwise around the processing chamber100. Thus, the substrate60will be exposed to the first process region250athrough the eighth process region250h, including all process regions between.

Embodiments of the disclosure are directed to processing methods comprising a processing chamber100with a plurality of process regions250a-250hwith each process region separated from an adjacent region by a gas curtain150. For example, the processing chamber shown inFIG. 5. The number of gas curtains and process regions within the processing chamber can be any suitable number depending on the arrangement of gas flows. The embodiment shown inFIG. 5has eight gas curtains150and eight process regions250a-250h.

A plurality of substrates60are positioned on a substrate support, for example, the susceptor assembly140shownFIGS. 1 and 2. The plurality of substrates60are rotated around the process regions for processing. Generally, the gas curtains150are engaged (gas flowing and vacuum on) throughout processing including periods when no reactive gas is flowing into the chamber.

Accordingly, one or more embodiments of the disclosure are directed to processing methods utilizing a batch processing chamber like that shown inFIG. 5. A substrate60is placed into the processing chamber which has a plurality of sections250, each section separated from adjacent section by a gas curtain150.

Some embodiments of the disclosure incorporate dynamic IR shields attached to the bottom surface of the susceptor and are rotated with the susceptor to create a permanent coverage under the wafer in areas of interest. Varying the shape of the shield can be used to modulate local temperatures on the wafer surface facing the showerhead. In some embodiments the shield is suspended from the bottom of the susceptor via a threaded fastener with locating features. Spacing between the shield and the susceptor can vary to further impact temperature distribution. The shield materials may also be selected in such a way that impact wafer temperature distribution.

Referring toFIG. 6, one or more embodiment of the disclosure is directed to susceptor assemblies600. The susceptor assemblies600comprise a susceptor610with a top surface612and a bottom surface614. A plurality of recesses642are formed in the top surface612of the susceptor610. The recesses642are sized to support a substrate (or wafer) during processing. The recess642shown inFIG. 6includes an outer peripheral ledge644to support an outer edge of the wafer. However, those skilled in the art will understand that the recess642can have a flat bottom, like that illustrated inFIG. 1. The outer peripheral ledge644is merely one possible configuration for the recess642.

A heater620is positioned below the susceptor610to heat the susceptor610. The heater620can be any suitable type of heater including, but not limited to, radiant heaters that emit infrared (IR) radiation to heat the bottom surface614of the susceptor610. In some embodiments, the heater620is not part of the susceptor assembly600and is separate from the susceptor610. In some embodiments, the heater is a separate component from the susceptor assembly. In some embodiments, the heater620is an infrared heater. In some embodiments, the heater620is not an induction heater.

A shield630is positioned between the bottom surface614of the susceptor610and the heater620. The shield630has a top surface632facing the bottom surface614of the susceptor and a bottom surface634facing the heater620. The shield630increases deposition uniformity across the recesses642of the susceptor610. In some embodiments, the shield630increases deposition uniformity and decreases temperature uniformity across the recesses642, and across the substrate.

FIGS. 7-9show embodiments of the susceptor assembly600. Each of these embodiments is shown looking at the bottom surface614of the susceptor610. The recesses642and ledge644are drawn dotted lines to show the location of the recesses on the non-visible side of the susceptor610. The recesses642are shown in this manner to illustrate the relative locations of the recesses and the shields.

In the embodiment ofFIG. 7, the shield630comprises a plurality of shield segments631. Each segment631is positioned in a region between recesses642in the top surface of the susceptor610. Each of the shield segments631inFIG. 7is wedge-shaped extending radially from a center161of the susceptor610toward an outer peripheral edge144of the susceptor610. The shield segments631shown do not overlap with the recesses642but it will be understood by those skilled in the art that there can be some overlap. In some embodiments, the shield630does not have a continuous shield surface that blocks direct line of sight between the heater620and the bottom surface614of the susceptor. In some embodiments, the shield segments are positioned decrease a local temperature of the susceptor to improve temperature uniformity.

FIG. 8shows another embodiment of the disclosure in which there are to different types of shield segments631. The first segments661are contoured to have a shape similar to the shape of the recesses642. The contoured regions662shown are rounded to mimic the shape of the recesses642adjacent that contoured regions662.

In some embodiments, the shield segments661are shaped to cover more of the leading edge647of the recess642than the trailing edge548of the adjacent recess642. Without being bound by any particular theory of operation, it is believed that the rotation of the susceptor610drags the process gases between the regions and that the leading edge647is exposed to a higher concentration of process gases. The shielding is believed to decrease the relative temperature near the leading edge so that the deposition is consistent with the center and trailing edge of the substrate, which is maintained at a higher temperature but with a lower local reactive gas concentration.

The second type of shield segments671shown inFIG. 8are aligned with the recesses642to overlap. As used in this regard, the term “overlap” means that the vertical positioning of the recesses and the shield segments are aligned. Those skilled in the art will understand that the shield segments are not located physically over the recesses. The shield segments671extend from a region inside the inner edge649of the recess642toward a center651of the recess642. The shield segment671can extend less than the center651, to the center651or beyond the center651of the recess642.

In some embodiments, the shield segments661are present without shield segments671. In some embodiments, shield segments671are present without shield segments661. In some embodiments, both shield segment661and shield segment671are present.

FIG. 9shows another embodiment of the susceptor assembly600in which the shield630is ring shaped. The ring has an inner edge681and an outer edge682. The inner edge681is closer to the center161of the susceptor610than the outer edge682.

In some embodiments, the inner edge681of the shield630is positioned within a first quarter of a width of the recess642. As used in this regard, the width of the recess642is defined as the distance from the point of the recess closest to the center161of the susceptor to the point of the recess furthest from the center161of the susceptor. The center of the recess642is at 50% of the width of the recess. In some embodiments, the inner edge681of the shield630is positioned within the inner 40%, 35%, 30%, 25%, 20%, 15%, 10% or 5% of the width of the recess. In some embodiments, the inner edge681is located outside the bounds of the recess closer to the center of the susceptor.

In some embodiments, the outer edge682of the shield630is positioned within a second half of the width of the recess642. In some embodiments, the outer edge682of the shield630is positioned within the outer 40%, 35%, 30%, 25%, 20%, 15%, 10% or 5% of the width of the recess. Stated differently, in some embodiments, the outer edge682of the shield630is positioned at a point greater than or equal to about 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% of the width of the recess. In some embodiments, the outer edge682of the shield630is located outside the outer edge of the recess.

In some embodiments, the inner edge of the shield is positioned within the first quarter (<25%) of the width of the recess and the outer edge of the shield is positioned within a fourth quarter (>75%) of the width of the recess. In some embodiments, the distance from the inner edge of the shield to the outer edge of the shield covers at least about ⅓, ½, or ⅔ of the width of the recess. In some embodiments, the distance from the inner edge of the shield to the outer edge of the shield covers at least about 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% of 70% of the width of the recess.

The shield630can be made from any suitable material. In some embodiments, the shield is made from one or more of stainless steel, aluminum oxide or aluminum nitride. In some embodiments, the shield comprises a dielectric material. In some embodiments, the shield comprises a ceramic material.

Referring again toFIG. 6, the shield630is positioned a distance from the bottom surface614of the susceptor610to form a gap G. In some embodiments, the gap G is in the range of about 0.25 mm to about 6 mm. In some embodiments, the gap G is greater than or equal to about 0.25 mm, 0.5 mm, 0.75 mm, 1 mm, 1.5 mm, 2 mm or 2.5 mm. In some embodiments, the gap G is less than or equal to about 6 mm, 5.5, mm, 5 mm, 4.5 mm, 4 mm or 3.5 mm. In some embodiments, the gap G is in the range of about 1 mm to about 5 mm, or in the range of about 2 mm to about 4 mm, or in the range of about 2.5 mm to about 3.5 mm, or about 3 mm.

The heater620is spaced a distance D from the shield630. In some embodiments, the heater620is spaced from the shield630a distance in the range of about 30 mm to about 80 mm, or in the range of about 4 mm to about 70 mm. In some embodiments, the heater620and the shield630are a distance apart greater than or equal to about 30 mm, 40 mm or 50 mm. In some embodiments, the heater620is about 60 mm from the shield630. In some embodiments, the heater620is a separate component from the susceptor610or shield630.

As shown inFIG. 6, in some embodiments, the susceptor assembly600includes a plurality of suspension rods695connected to the susceptor610. The suspension rods695can support the shield630and maintaining a gap G between the shield630and the susceptor610. The suspension rods695can pass through an opening690in the shield630. In some embodiments, each of the suspension rods695comprises a shoulder screw696to connect the shield630to the suspension rod695.

A controller680includes central processing unit (CPU)682, memory684, and support circuits686. Central processing unit682may be one of any form of computer processor that can be used in an industrial setting for controlling various chambers and sub-processors. Memory684is coupled to CPU682and may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), flash memory, compact disc, floppy disk, hard disk, or any other form of local or remote digital storage. Support circuits686are coupled to CPU682for supporting CPU682in a conventional manner. These circuits may include cache, power supplies, clock circuits, input/output circuitry, subsystems, and the like.

In some embodiments, the controller includes a non-transitory computer-readable medium containing computer code that, when executed by operation of one or more computer processors, performs an operation for controlling deposition processes in the chamber. The computer code can include instruction sets for the processor to enable the processor to, inter alia, control the heaters (power, temperature, position), heat shields, susceptor assembly rotation and lift and/or the gas distribution assembly including gas flows.

The computer program code of some embodiments includes data models defining acceptable levels within the chamber for each of a plurality of gas types. The computer program code can include models or look-up tables to determine heater power settings for temperature control. In some embodiments, the computer program code includes models to determine position of one or more heat shields based on temperature feedback circuits.

In some embodiments, each shield segment631,661,671is supported by at least three suspension rods695. In some embodiments, each shield segment631,661,671comprises at least three openings690to allow the suspension rod to pass therethrough. As can be seen inFIGS. 7 and 8, some embodiments of the shield segments have three openings690.

As shown inFIG. 9, some embodiments of the shield630include a plurality of protrusions685extending inwardly from the inner edge681. The protrusions685can include an opening690to allow a suspension rod to pass therethrough. In some embodiments, the shield630is supported by six suspension rods passing through six openings690in the shield630.

According to one or more embodiments, the substrate is subjected to processing prior to and/or after forming the layer. This processing can be performed in the same chamber or in one or more separate processing chambers. In some embodiments, the substrate is moved from the first chamber to a separate, second chamber for further processing. The substrate can be moved directly from the first chamber to the separate processing chamber, or it can be moved from the first chamber to one or more transfer chambers, and then moved to the separate processing chamber. Accordingly, the processing apparatus may comprise multiple chambers in communication with a transfer station. An apparatus of this sort may be referred to as a “cluster tool” or “clustered system,” and the like.

Generally, a cluster tool is a modular system comprising multiple chambers which perform various functions including substrate center-finding and orientation, annealing, annealing, deposition and/or etching. According to one or more embodiments, a cluster tool includes at least a first chamber and a central transfer chamber. The central transfer chamber may house a robot that can shuttle substrates between and among processing chambers and load lock chambers. The transfer chamber is typically maintained at a vacuum condition and provides an intermediate stage for shuttling substrates from one chamber to another and/or to a load lock chamber positioned at a front end of the cluster tool. Two well-known cluster tools which may be adapted for the present disclosure are the Centura® and the Endura®, both available from Applied Materials, Inc., of Santa Clara, Calif. However, the exact arrangement and combination of chambers may be altered for purposes of performing specific steps of a process as described herein. Other processing chambers which may be used include, but are not limited to, cyclical layer deposition (CLD), atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etch, pre-clean, chemical clean, thermal treatment such as RTP, plasma nitridation, anneal, orientation, hydroxylation and other substrate processes. By carrying out processes in a chamber on a cluster tool, surface contamination of the substrate with atmospheric impurities can be avoided without oxidation prior to depositing a subsequent film.

According to one or more embodiments, the substrate is continuously under vacuum or “load lock” conditions, and is not exposed to ambient air when being moved from one chamber to the next. The transfer chambers are thus under vacuum and are “pumped down” under vacuum pressure. Inert gases may be present in the processing chambers or the transfer chambers. In some embodiments, an inert gas is used as a purge gas to remove some or all of the reactants. According to one or more embodiments, a purge gas is injected at the exit of the deposition chamber to prevent reactants from moving from the deposition chamber to the transfer chamber and/or additional processing chamber. Thus, the flow of inert gas forms a curtain at the exit of the chamber.

The substrate can be processed in single substrate deposition chambers, where a single substrate is loaded, processed and unloaded before another substrate is processed. The substrate can also be processed in a continuous manner, similar to a conveyer system, in which multiple substrate are individually loaded into a first part of the chamber, move through the chamber and are unloaded from a second part of the chamber. The shape of the chamber and associated conveyer system can form a straight path or curved path. Additionally, the processing chamber may be a carousel in which multiple substrates are moved about a central axis and are exposed to deposition, etch, annealing, cleaning, etc. processes throughout the carousel path.

During processing, the substrate can be heated or cooled. Such heating or cooling can be accomplished by any suitable means including, but not limited to, changing the temperature of the substrate support and flowing heated or cooled gases to the substrate surface. In some embodiments, the substrate support includes a heater/cooler which can be controlled to change the substrate temperature conductively. In one or more embodiments, the gases (either reactive gases or inert gases) being employed are heated or cooled to locally change the substrate temperature. In some embodiments, a heater/cooler is positioned within the chamber adjacent the substrate surface to convectively change the substrate temperature.

The substrate can also be stationary or rotated during processing. A rotating substrate can be rotated continuously or in discreet steps. For example, a substrate may be rotated throughout the entire process, or the substrate can be rotated by a small amount between exposures to different reactive or purge gases. Rotating the substrate during processing (either continuously or in steps) may help produce a more uniform deposition or etch by minimizing the effect of, for example, local variability in gas flow geometries.

In atomic layer deposition type chambers, the substrate can be exposed to the first and second precursors either spatially or temporally separated processes. Temporal ALD is a traditional process in which the first precursor flows into the chamber to react with the surface. The first precursor is purged from the chamber before flowing the second precursor. In spatial ALD, both the first and second precursors are simultaneously flowed to the chamber but are separated spatially so that there is a region between the flows that prevents mixing of the precursors. In spatial ALD, the substrate is moved relative to the gas distribution plate, or vice-versa.

In embodiments, where one or more of the parts of the methods takes place in one chamber, the process may be a spatial ALD process. Although one or more of the chemistries described above may not be compatible (i.e., result in reaction other than on the substrate surface and/or deposit on the chamber), spatial separation ensures that the reagents are not exposed to each in the gas phase. For example, temporal ALD involves the purging the deposition chamber. However, in practice it is sometimes not possible to purge the excess reagent out of the chamber before flowing in additional regent. Therefore, any leftover reagent in the chamber may react. With spatial separation, excess reagent does not need to be purged, and cross-contamination is limited. Furthermore, a lot of time can be used to purge a chamber, and therefore throughput can be increased by eliminating the purge step.