WO2004094692A1

WO2004094692A1 - Continuous flow atomic layer deposition system

Info

Publication number: WO2004094692A1
Application number: PCT/US2004/006455
Authority: WO
Inventors: Piero Sferlazzo
Original assignee: Fluens Corporation
Priority date: 2003-03-28
Filing date: 2004-03-03
Publication date: 2004-11-04
Also published as: US20040187784A1; US6972055B2

Abstract

An atomic layer deposition system is described that includes a deposition chamber. A first and second reaction chamber are positioned in the deposition chamber and contain a first and a second reactant species, respectively. A monolayer of the first reactant species is deposited on a substrate passing through the first reaction chamber. A monolayer of the second reactant species is deposited on a substrate passing through the second reaction chamber. A transport mechanism transports a substrate in a path through the first reaction chamber and through the second reaction chamber, thereby depositing a film on the substrate by atomic layer deposition. The shape of the first and the second reaction chambers are chosen to achieve a constant exposure of the substrate to reactant species when the transport mechanism transports the substrate in the path through the respective reaction chambers at the constant transport rate.

Description

SPECIFICATION

CONTINUOUS FLOW ATOMIC LAYER DEPOSITION SYSTEM

Cross Reference to Related Applications

This patent application claims priority to U.S. provisional patent application Serial No. 60/320,065, filed on March 28, 2003, the entire disclosure of which is incorporated herein by reference.

Background of Invention

[0001 ] Chemical Vapor Deposition (CVD) is widely used to deposit dielectrics and metallic thin films. There are many techniques for performing CVD. For example, CVD can be preformed by introducing two or more precursor molecules in the gas phase (i.e., precursor gas A molecule and precursor gas B molecule) into a process chamber

-3 containing a substrate or work piece at pressures varying from less than 1 0 Torr to atmosphere.

[0002] The reaction of precursor gas molecule A and precursor gas molecule B at a surface of a substrate or work piece is activated or enhanced by adding energy. Energy can be added in many ways. For example, energy can be added by increasing the temperature at the surface and/or by exposing the surface to a plasma discharge or an ultraviolet (UV) radiation source. The product of the reaction is the desired film and some gaseous by-products, which are typically pumped away from the process chamber.

[0003]

Most CVD reactions occur in the gaseous phase. The CVD reactions are strongly dependent on the spatial distribution of the precursor gas molecules. Non-uniform gas flow adjacent to the substrate can result in poor film uniformity and shadowing effects in three-dimensional features, such as vias, steps and other over-structures. The poor film uniformity and shadowing effects result in poor step coverage. In addition, some of the precursor molecules stick to a surface of the CVD chamber and react with other impinging molecules, thereby changing the spatial distribution of the precursor gases and, therefore, the uniformity of the deposited film.

Brief Description of Drawings

[0004] This invention is described with particularity in the detailed description. The above and further advantages of this invention may be better understood by referring to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

[0005] FIG. 1 illustrates a perspective view of an embodiment of an ALD system according the present invention.

[0006] FIG. 2 illustrates a flow chart of a method of performing ALD according to the present invention for the ALD system described in connection with FIG. 1 .

[0007] FIG. 3 illustrates a top view of the ALD system of FIG. 1 that shows a particular reaction chamber and gas injection manifold design according to the present invention.

[0008] FIG. 4A,B illustrate two embodiments of a gas injection manifold for an ALD system according to the present invention.

[0009] FIG. 5 illustrates a perspective view of an embodiment of an ALD system having a reaction chamber including a plasma generator that is used for plasma enhanced ALD processing.

[001 0] FIG. 6 illustrates a perspective view of an embodiment of an ALD system including a plurality of reaction chambers according the present invention.

[001 1 ] FIG. 7 illustrates a perspective view of an embodiment of an ALD system that includes reaction chambers that rotate relative to the substrates according the present invention.

[001 2] . FIG. 8A,B illustrate two techniques of sealing the reaction chambers according to the present invention to prevent reactants from escaping from the reaction chambers. [001 3] FIG. 9 illustrates a differentially pumped interface that can be used to seal the reaction chambers according to the present invention to prevent reactants from escaping from the reaction chambers.

Detailed Description

[0014] Atomic Layer Deposition (ALD) is a variation of CVD that uses a self-limiting reaction. The term "self-limiting reaction" is defined herein to mean a reaction that limits itself in some way. For example, a self-limiting reaction can limit itself by terminating after a reactant is completely consumed by the reaction. One method of ALD sequentially injects a pulse of one type of precursor gas into a reaction chamber. After a predetermined time, another pulse of a different type of precursor gas is injected into the reaction chamber to form a monolayer of the desired material. This method is repeated until a film having the desired thickness is deposited onto the surface of the substrate.

[001 5] For example, ALD can be performed by sequentially combining precursor gas A and precursor gas B in a process chamber. In a first step, a gas source injects a pulse of precursor gas A molecules into the process chamber. After a short exposure time, a monolayer of precursor gas A molecules deposits on the surface of the substrate. The process chamber is then purged with an inert gas.

[001 6] During the first step, precursor gas A molecules stick to the surface of the substrate in a relatively uniform and conformal manner. The monolayer of precursor gas A molecules covers the exposed areas including vias, steps and surface structures in a relatively conformal manner with relatively high uniformity and minimal shadowing.

[001 7] Process parameters, such as chamber pressure, surface temperature, gas injection time, and gas flow rate can be selected so that only one monolayer remains stable on the surface of the substrate at any given time. In addition, the process parameters can be selected for a particular sticking coefficient. Plasma pre-treatment can also be used to control the sticking coefficient.

In a second step, another gas source briefly injects precursor gas B molecules into the process chamber. A reaction between the injected precursor gas B molecules and the precursor gas A molecules that are stuck to the substrate surface occurs and that forms a monolayer of the desired film that is typically about 1 -2 Angstroms thick. This reaction is self-limiting because the reaction terminates after all the precursor gas A molecules are consumed in the reaction. The process chamber is then purged with an inert gas.

[001 9] The monolayer of the desired film covers the exposed areas including vias, steps and surface structures in a relatively conformal manner with relatively high uniformity and minimal shadowing. The precursor gas A and the precursor gas B molecules are then cycled sequentially until a film having the desired total film thickness is deposited on the substrate. Cycling the precursor gas A and the precursor gas B prevents reactions from occurring in the gaseous phase and generates a more controlled reaction.

[0020] Atomic Layer Deposition has been shown to be effective in producing relatively uniform, pinhole-free films having thickness that are only a few Angstroms thick. Dielectrics have been deposited using ALD that exhibit relatively high breakdown voltages and relatively high film integrity compared with other methods, such as PVD, thermal evaporation and CVD.

[0021 ] However, in practice, secondary effects, such as non-uniform flow distribution and residual cross-contamination, limit the achievable uniformity and integrity of films deposited by ALD. These secondary effects, although much less pronounced compared with known CVD methods, are significant limitations that prevent ALD from being useful for some applications.

[0022] There have been many attempts to improve the uniformity and integrity of ALD films with varying success. For example, researchers have developed new precursor gas chemistries, new techniques for surface pre-treatment, and new methods for injecting precursor gases at precise times in efforts to improve the uniformity and integrity of ALD films.

[0023]

The ALD processing system according to the present invention eliminates non- uniformities and poor film integrity that are caused when the precursor gas sources are cycled by injection and purging in known ALD systems. The ALD system according to the present invention includes at least two spatially separated reaction chambers and a transport mechanism that transports substrates relative to the reaction chambers. The substrates can be transported relative to the reaction chambers in a continuous motion. Another transport mechanism can transport the reaction chambers relative to the substrates.

[0024] FIG. 1 illustrates a perspective view of an embodiment of an ALD system 1 00 according the present invention. The ALD system 100 includes a deposition chamber 102 that includes a first 104 and a second reaction chamber 106, a processing region 108, and a transport mechanism 1 1 0 that supports substrates 1 1 2 and transfers the substrates 1 1 2 relative to the first reaction chamber 104, the second reaction chamber 1 06, and the processing region 1 08.

[0025] A vacuum pump 1 14 is positioned in fluid communication with the deposition chamber 1 02. The vacuum pump 1 14 evacuates the deposition chamber 1 02 to the desired operating pressure. The vacuum pump 1 1 4 and the associated control system can also be used to control the pressure during processing and can purge the deposition chamber 1 02 of reactant gases and gas by-products during and after processing.

[0026] The first 104 and the second reaction chamber 1 06 are positioned inside of the deposition chamber 102 and are designed to contain a reactant and also to prevent that reactant species from escaping into other areas of the deposition chamber 102. There are numerous ways to seal the reaction chambers 1 04, 1 06 relative to the deposition chamber 1 02 to prevent reactants from escaping from the reaction chambers 1 04, 1 06 as described herein.

[0027] In practice, however, there may be some relatively small residual quantity of precursor gas molecules that escape from the reaction chambers 1 04, 1 06 or that remain on the surface of the substrates 1 1 2. The residual quantity of precursor gases is generally less than the quantity that is required to cause a significant reaction on the surface of the substrate 1 1 2.

[0028]

The reaction chambers 1 04, 1 06 each include a gas injection manifold 1 1 6a,b that injects precursor gas molecules into the reaction chambers 1 04, 106. Numerous types of gas injection manifolds can be used. The shape of the gas injection manifold 1 1 6a,b can be chosen to provide a substantially constant flow of reactant species as the substrate passes through the reaction chambers 1 04, 1 06 at a particular rotation rate. The ALD system 1 00, however, does not require a gas injection system with precise control over the gas injection volume and time interval of injection that is commonly used in many other known ALD systems. Therefore, the ALD system 1 00 is relatively simple and inexpensive to manufacture.

[0029] In one embodiment, at least one of the reaction chambers 104, 106 includes a plasma generator that is used for plasma enhanced ALD processing. The plasma generator can be physically located 'in the reaction chambers 1 04, 1 06 so that it generates a plasma directly in the reaction chambers 1 04, 1 06. Alternatively, the plasma generator can be remotely located relative to the reaction chambers 1 04, 1 06 in a downstream configuration. In the downstream configuration, a plasma is generated by a remote plasma source that is physically located outside of the reaction chambers 1 04, 1 06 and then the plasma is directed into the reaction chambers 1 04, 106.

[0030] The processing region 108 is positioned inside the deposition chamber 102 and includes one or more apparatus 1 1 8 for performing at least one surface treatment or combination of surface treatments on the substrates 1 1 2 passing through the processing region 1 08. The apparatus 1 1 8 for performing the surface treatments on the substrates can be physically located inside the processing region 1 08 or can be remotely located relative to the processing region 1 08 as shown in FIG. 1 . In one embodiment, the processing region 1 08 is shaped so as to causes a substantially constant exposure of the surface treatment performed on the substrates 1 1 2 passing through the processing region 1 08.

[0031 ]

The apparatus 1 1 8 for performing the surface treatments in the processing region 1 08 can perform one or more types of surface treatments. For example, the apparatus 1 1 8 in the processing region 1 08 can be used to clean the surface of the substrates 1 1 2 passing through the processing region 1 08. The apparatus 1 1 8 in the processing region 1 08 can also be used to modify the sticking coefficient on the surface of the substrates 1 1 2 and/or to activate a reaction on the surface of the substrates 1 1 2. In addition, the apparatus 1 1 8 in the processing region 108 can be used to deposit a metallic, semiconductor, or dielectric film on the surface of the substrates 1 1 2.

[0032] In one embodiment, the apparatus 1 18 in the processing region 108 is a plasma generator. The plasma generator can be used to expose the substrates 1 1 2 passing through the processing region 1 08 to a plasma that performs a surface treatment on the substrates 1 1 2. For example, the plasma generator can be a magnetron plasma generator. Alternatively, the plasma generator can be a down-stream plasma generator, such as a down-stream microwave or ECR plasma source, that is remotely located relative to the processing region 108.

[0033] The plasma generated by the plasma generator can be used to clean the surface of the substrates 1 1 2 before ALD processing. In addition, the plasma generated by the plasma generator can be used to surface treat the substrates 1 1 2 between exposures of precursor gas molecules during ALD processing. In addition, the plasma generated by the plasma generator can be used to sputter metallic or dielectric material on the surface of the substrates 1 1 2.

[0034] In one embodiment, the apparatus 1 1 8 for performing surface treatments in the processing region 1 08 is an energy source. For example, the apparatus 1 1 8 for performing surface treatments can include at least one of an ion beam source, an electron beam source or an UV radiation source. The energy source can be positioned inside the processing region 108 or can be remotely located relative to the processing region 1 08 as shown in FIG. 1 . In this embodiment, the processing region 1 08 is used to expose the substrates 1 1 2 to an energy source. The energy source can be used for many applications, such as activating a reaction on the surface of the substrate 1 1 2, removing by-product materials, and cleaning the surface of the substrates 1 1 2.

[0035] The energy source can include a distribution grid 1 20 to direct the energy to substrates 1 12 passing through the processing region 108. In one embodiment, the hole pattern in the distribution grid 1 20 is chosen so that the substrates 1 1 2 are exposed to a constant dose of energy as they pass through the processing region 1 08.

[0036]

The transport mechanism 1 10 includes at least one substrate support 1 22 that supports the substrates 1 1 2 or work pieces during ALD processing. In one embodiment, the transport mechanism 1 1 0 is mechanically connected to a motor 1 24 that rotates the substrate support 1 22. The desired number of substrate supports 1 22 depends upon the desired throughput of the ALD system 1 00. A port 1 26 in the deposition chamber 1 02 provides access to inside the deposition chamber 1 02 so that the substrates 1 1 2 can be transported onto the substrate supports 1 22 for ALD processing and removed from the deposition chamber 1 02 after ALD processing.

[0037] In one embodiment, a transfer mechanism (not shown) positions the substrates

1 1 2 adjacent to the port 126 so that the substrates 1 12 can be easily transported to and from the substrate supports 1 22. In one embodiment (not shown), the port 1 26 is in fluid communication with another processing tool (not shown) so that substrates 1 1 2 can be transported to and from the other processing tool without exposing the substrates 1 1 2 to atmospheric pressure. For example, the deposition chamber 102 can be part of a cluster tool (not shown) in which the substrates 1 1 2 are transported to and from another process chamber in the cluster tool to and from the deposition chamber 1 02.

[0038] The transport mechanism 1 10 transports at least one substrate 1 1 2 relative to the first reaction chamber 1 04, the second reaction chamber 1 06, and the processing region 1 08. In one embodiment, the transport mechanism 1 10 transports the substrate supports 1 22 holding the substrates 1 1 2 while the first 1 04 and the second reaction chamber 1 06 remain in a fixed position. In this embodiment, the transport mechanism 1 1 0 transports the substrate supports 1 22 in a path through the first reaction chamber 1 04, through the second reaction chamber 1 06, and through the processing region 1 08 during ALD processing.

[0039] For example, the transport mechanism 1 10 can be a rotating member, such as a rotating disk, that is attached to the substrate supports 1 22 and the motor 1 24. The rotating member rotates the substrates 1 1 2 in the path through the first reaction chamber 1 04, through the second reaction chamber 106, and through the processing region 1 08. The rotating member transport mechanism 1 1 0 can provide a high- degree of deposition uniformity because of the rotational symmetry provided by the disk. [0040] In another embodiment, the transport mechanism 1 1 0 transports the first reaction chamber 1 04, the second reaction chamber 1 06, and the processing region 1 08 relative to the substrates 1 1 2, while the substrates 1 1 2 remain in a fixed position. For example, in this embodiment, the reaction chambers 104, 1 06 and the processing region 108 are attached to a rotating member (not shown) that rotates the reaction chambers 1 04, 1 06 and the processing region 1 08 relative to the substrate supports 1 22.

[0041 ] In yet another embodiment, the transport mechanism 1 10 rotates the substrates

1 1 2, the reaction chambers 1 04, 106, and the processing region 108 relative to each other. For example, in this embodiment, the reaction chambers 1 04, 1 06 and the processing region 1 08 are attached to a first rotating member (not shown) and the substrate supports 1 22 are attached to a second rotating member (not shown).

[0042] FIG. 2 illustrates a flow chart 1 50 of a method of performing ALD according to the present invention for the ALD system 1 00 described in connection with FIG. 1 . The method is described in connection with the ALD system of FIG. 1 where the first 104 and the second reaction chamber 1 06 remain in a fixed position while the substrates 1 1 2 are transported through the reaction chambers 1 04, 1 06. However, other embodiments in which the substrates 1 1 2 and/or the reaction chambers 1 04, 106 are transported are within the scope of the present invention.

[0043] In a first step 1 52, the deposition chamber 1 02 is evacuated to the desired operating pressure by the vacuum pump 1 14. In a second step 1 54, precursor gas A molecules are injected into the first reaction chamber 1 04 to create the desired partial pressure of precursor gas A in the first reaction chamber 104. In some embodiments, precursor gas A and a second precursor gas are injected into the first reaction chamber 1 04. Also, in some embodiments, precursor gas A and a non-reactive gas are injected into the first reaction chamber 104. In one embodiment, the temperature of the first reaction chamber 104 is controlled to a temperature that promotes the desired reaction with the surface of the substrates 1 1 2 passing through the first reaction chamber 1 04.

[0044] |_{n a tn}j_rc| _step ι _56ι precursor gas B molecules are injected into the second reaction chamber 1 06 to create the desired partial pressure of precursor gas B. In some embodiments, precursor gas B and a second precursor gas are injected into the second reaction chamber 1 06. Also, in some embodiments, precursor gas B and a non-reactive gas are injected into the second reaction chamber 1 06. In one embodiment, the temperature of the second reaction chamber 1 06 is controlled to a temperature that promotes the desired reaction with the surface of the substrates 1 1 2 passing through the second reaction chamber 1 06. The second step 1 54 and the third step 1 56 can be performed in any order or can be performed simultaneously.

[0045] In one embodiment, a fourth step 1 58 is used to pre-treat a substrate 1 1 2 in the deposition chamber 1 02. For example, in the fourth step 1 58, the substrate can be exposed to a plasma or energy source, such as an ion beam, electron beam, or UV radiation source. The pre-treatment can clean the substrate 1 1 2 and/or control the sticking coefficient on the surface of the substrate 1 1 2. The fourth step 1 58 can be performed at any time during the process. For example, the fourth step 1 58 can also be performed directly after the deposition chamber 102 is evacuated to the desired operating pressure in the first step 1 52.

[0046] In a fifth step 1 60, the substrate 1 1 2 is transported from the deposition chamber

102 to the first reaction chamber 1 04. The substrate 1 1 2 is then transported through the first reaction chamber 1 04 to expose the substrate 1 1 2 to precursor gas A molecules. In some embodiments, the substrate 1 1 2 is processed while it is being transported through the first reaction chamber 104.

[0047] The transportation or rotation rate is chosen so that the substrate 1 1 2 remains in the first reaction chamber 1 04 for a first predetermined time that is sufficient to cause the desired exposure of the substrate 1 1 2 to the partial pressure of precursor gas A molecules in the first reaction chamber 1 04. In some embodiments, the first predetermined time is also chosen so that the substrate 1 1 2 has the desired exposure to the ALD processing. During the first predetermined time, precursor gas A molecules stick to the surface of the substrate 1 1 2 in a highly uniform and conformal manner and form a monolayer of precursor gas A molecules that covers every exposed area including vias, steps and surface structures.

[0048] In a sixth step 1 62, the substrate 1 12 containing the monolayer of precursor gas A molecules is transported out of the first reaction chamber 1 04 and back into the deposition chamber 1 02. In one embodiment, in a seventh step 1 64, the substrate 1 1 2 containing the monolayer of precursor gas A molecules are processed in the processing region 1 08 of the deposition chamber 1 02. For example, in one embodiment, the substrate 1 12 is exposed to a plasma, an energy source, or other type of surface treatment in the deposition chamber 102.

[0049] In an eighth step 1 66, the substrate 1 1 2 containing the monolayer of precursor gas A molecules is transported from the deposition chamber 1 02 to the second reaction chamber 106. The substrate 1 12 is then transported through the second reaction chamber 1 06 to expose the substrate 1 1 2 to precursor gas B molecules. In some embodiments, the substrate 1 1 2 is processed while it is being transported through the second reaction chamber 1 06.

[0050] The transportation or rotation rate is chosen so that the substrate 1 1 2 remains in the second reaction chamber 1 06 for a second predetermined time that is sufficient to cause the desired exposure of the substrate 1 1 2 to the partial pressure of precursor gas B molecules in the second reaction chamber 106. In some embodiments, the second predetermined time is also chosen so that the substrate 1 1 2 has the desired exposure to the ALD processing.

[0051 ] During the second predetermined time, precursor gas B molecules stick to the surface of the conformal coating of precursor gas A molecules. A reaction between the precursor gas B molecules and the precursor gas A molecules occurs. The reaction is self-limiting because the reaction terminates after all the precursor gas A molecules are consumed in the reaction. A monolayer of the desired film develops on the surface of the substrate 1 1 2 that is typically about 1 -2 Angstroms thick. The monolayer covers all of the exposed areas, including vias, steps or surface structures, in a relatively uniform manner without any shadowing.

[0052] _{!n a} ninth _{s e}p i 68, the substrate 1 1 2 is transported out of the second reaction chamber 1 06 and back into the deposition chamber 1 02. In one embodiment, in a tenth step 1 70 the substrate 1 1 2 containing the monolayer of the desired film is processed in processing region 108 of the deposition chamber 1 02. For example, in one embodiment, the substrate 1 1 2 is exposed to a plasma, ion beam, electron beam or other type of surface treatment while in the processing region 1 08 of the deposition chamber 1 02. The substrate 1 1 2 remains in the deposition chamber 1 02 for a predetermined time interval.

[0053] The fifth step 1 60 through the tenth step 1 70 are then repeated until a film having the desired film thickness and film properties is deposited on the surface of the substrate 1 1 2. Thus, the substrate 1 1 2 is sequentially transported from the deposition chamber 1 02 to the first reaction chamber 104, back to the processing region 1 08 in the deposition chamber 1 02, to the second reaction chamber 1 06, and then back to the deposition chamber 102.

[0054] In one embodiment, the substrate 1 1 2 is rotated at a substantially continuous rotation rate from the deposition chamber 102 to the first reaction chamber! 04, back to the processing region 108 of the deposition chamber 1 02, to the second reaction chamber 1 06, and then back to the deposition chamber 1 02. The time period that the substrate 1 1 2 is exposed to the precursor gas A molecules and the precursor gas B molecules in the first 104 and the second reaction chamber 1 06, respectively, is determined by the rotation rate of the substrate 1 1 2 within the deposition chamber 102. Also, the time periods that the substrate 1 1 2 is pretreated in the fourth step 1 58, and processed in the seventh 1 64 and the tenth step 1 70, is determined by the rotation rate of the substrate 1 1 2 within the deposition chamber 1 02.

[0055] There are many different configurations and embodiments of the reaction chambers 1 04, 1 06 and the gas injection manifolds 1 1 6a,b of the ALD system 100 according to the present invention. FIG. 3 illustrates a top view 200 of the ALD system of FIG. 1 that shows a particular reaction chamber and gas injection manifold design according to the present invention.

[0056] The reaction chambers 1 04, 106 shown in FIG. 3 are shaped and positioned to achieve a constant exposure of the substrates 1 1 2 to reactant species when the transport mechanism 1 10 transports the substrates 1 1 2 in the path through the reaction chambers 1 04, 1 06 at a constant rotation rate. In the embodiment shown, a first 202 and a second radial edge 204 of the first 1 04 and the second reaction chamber 1 06 are approximately aligned to a center 206 of the deposition chamber 102. [0057] This design provides a constant exposure to substrates 1 1 2 passing through the reaction chambers 1 04, 1 06 by compensating for the radial dependence on the velocity of the substrates 1 12 rotating through the reaction chambers 1 04, 106. Providing a constant exposure can increase the throughput a deposition system because the predetermined exposure times can be minimized. Providing a constant exposure can even increase the throughput of ALD deposition systems having self- limiting reactions because achieving a constant exposure will eliminate the need to over-expose some areas of the substrates 1 1 2.

[0058] The top view 200 of the ALD system of FIG. 1 also shows the gas flow of a particular gas injection manifold design according to the present invention. The gas injection manifolds 1 1 6a,b inject precursor gas A into the first reaction chamber 104 and precursor gas B into the second reaction chamber 1 06. In the embodiment shown, the gas manifolds 1 1 6a,b are delta shaped. The delta shape is chosen so as to maintain a uniform gas flow over the reaction chambers 104, 106, while the substrates 1 1 2 are transported through the reaction chambers 1 04, 1 06 at a constant rotation rate. In one embodiment, the precursor gases flow from the center gas manifold section 1 1 6a to the outer gas manifold section 1 1 6b as shown by the arrows 208.

[0059] The top view 200 of the ALD system of FIG. 1 also shows the distribution grid 1 20 that is used to direct the energy to substrates 1 1 2 passing through the processing region 1 08. In the embodiment shown, the grid 1 20 defines apertures in a delta shaped pattern so as to expose substrates 1 1 2 rotating through the processing region 1 08 at a constant rotation rate to a constant dose of energy.

[0060]

FIG. 4A,B illustrate two embodiments of a gas injection manifold 250, 252 for an ALD system according to the present invention. FIG. 4A illustrates the gas injection manifold 1 1 6a, b that includes the center gas manifold section 1 1 6a and the outer gas manifold section 1 1 6b that were described in connection with FIG. 2. An input arrow 254 indicates the flow of precursor gases from a gas source (not shown) into the center gas manifold section 1 1 6a. A plurality of arrows 256 indicate the flow of precursor gas from the center gas manifold section 1 1 6a to the outer gas manifold section 202b. An output arrow 258 indicates the flow of precursor and by-product gases flowing from the reaction chambers 1 04, 1 06 to an exhaust gas system (not shown).

[0061 ] FIG. 4B illustrates another embodiment of a gas injection manifold 252 of an ALD system according to the present invention. The gas injection manifold 252 includes a main manifold section 260 and three gas distribution sections 262. An input arrow 264 indicates the flow of precursor gases from a gas source (not shown) into the main manifold section 260. A plurality of arrows 264 indicate the flow of precursor gas from the three gas distribution sections 262 into the reaction chambers 104, 1 06.

[0062] FIG. 5 illustrates a perspective view of an embodiment of an ALD system 280 having a reaction chamber 282 including a plasma generator 284 that is used for plasma enhanced ALD processing. The ALD system 280 is similar to the ALD system 100 described in connection with FIG. 1 . However, the ALD system 280 includes the reaction chamber 282 having the plasma generator 284. The plasma generator 284 generates a plasma 286 that is used for the plasma enhanced processing.

[0063] The plasma generator 284 can be physically located in the reaction chamber 282 as shown in FIG. 5 so that it generates the plasma 286 directly in the reaction chamber 282. Alternatively, the plasma generator 284 can be remotely located relative to the reaction chamber 282 in a downstream configuration. In the downstream configuration, the plasma 286 is generated by a remote plasma source (not shown) that is physically located outside of the reaction chamber 282 and then the plasma 286 is directed into the reaction chamber 282.

[0064] FIG. 6 illustrates a perspective view of an embodiment of an ALD system 300 including a plurality of reaction chambers according the present invention. The deposition chamber 102 includes four reaction chambers: a first 302, second 304, third 306, and fourth reaction chamber 308. In other embodiments, the ALD system 300 includes additional reaction chambers (i.e. a fifth and sixth, etc.). The ALD system 300 also includes the processing region 108 that can include the apparatus 1 1 8 (FIG. 1 ) for performing surface treatments that is described herein. The transport mechanism 1 10 transfers the substrates 1 1 2 relative to the first 302, second 304, third 306, and fourth reaction chambers 308, and the processing region 108 (FIG. 3) as described herein. [0065] In addition, the deposition chamber 102 includes a port 1 26 that provides access to inside the deposition chamber 1 02 so that the substrates 1 1 2 can be inserted for processing and removed after processing. In one embodiment, the ALD system 300 includes a transfer mechanism (not shown) that positions the substrates 1 1 2 adjacent to the port 1 26 so that the substrates 1 1 2 can be easily inserted and removed from the deposition chamber 1 02.

[0066] The third 306 and fourth reaction chamber 308 can contain the same precursor gases as the first 302 and the second reaction chamber 304 and can be used to increase the throughput. In this embodiment, one rotation of the substrates 1 1 2 deposits two monolayers of the desired film.

[0067] Alternatively, the third 306 and fourth reaction chamber 308 can contain different precursor gases that are used to deposit a different type of material on the substrates 1 1 2. For example, in this embodiment, the third 306 and the fourth reaction chamber 308 contain precursor gas C and precursor gas D, respectively, that are different from precursor gas A and precursor gas B.

[0068] Monolayers of two different types of material can be deposited in any desired sequence. A predetermined number of monolayers of one type of film can be deposited on the surface of a substrate 1 1 2 and then a predetermined number of monolayers of another type of film can be deposited on the surface of the substrate 1 1 2. Additional reaction chambers (i.e. a fifth and sixth, etc.) can be added to further increase the number of different types of monolayers that can be deposited on the surface of the substrate 1 12.

[0069] The ALD system 300 of the present invention has relatively high throughput and can be scaled to accommodate a relatively high volume of substrates because multiple substrates 1 1 2 can be simultaneously processed. For example, multiple substrates 1 1 2 can be processed simultaneously in the ALD system 300 by sequentially rotating substrates 1 1 2 in the deposition chamber 1 02 to the first reaction chamber 302, back to the deposition chamber 1 02, to the second reaction chamber 304, back to the deposition chamber 1 02, to the third reaction chamber 306, back to the deposition chamber 1 02, to the fourth reaction chamber 308, and then back to the deposition chamber 1 02. [0070] FIG. 7 illustrates a perspective view of an embodiment of an ALD system 350 that includes reaction chambers 352, 354 that rotate relative to the substrates 1 1 2 according the present invention. The ALD system 350 includes a first 352 and a second reaction chamber 354 that rotate in the deposition chamber 102 so as to cause a relative motion between the substrates 1 1 2 and the reaction chambers 352, 354.

[0071 ] The reaction chambers 352, 354 are attached to a rotating member 356, which is rotated by a motor (not shown) that is mechanically coupled to a shaft 358. The rotation rate of the rotating member 356 can be precisely controlled. In one embodiment, the reaction chambers 352, 354 are rotated at a constant rotation rate relative to the substrates 1 1 2. In one embodiment, the substrates 1 1 2 are rotated relative to the reaction chambers 352, 354 to increase or decrease the relative motion between the substrates 1 1 2 and the reaction chambers 352, 354.

[0072] In another embodiment, the reaction chambers 352, 354 are attached to independent rotating members. For example, the reaction chambers 352, 354 can be attached to a first and a second rotating member, respectively. In one embodiment, the rotating members are gears that are mechanically coupled to the reaction chambers 352, 354. The first and the second rotating members are rotated so as to cause the desired relative motion between the substrates 1 1 2 and the reaction chambers 352, 354. The first and the second rotating members can be rotated in the same or in the opposite direction.

[0073] FIG. 8A,B illustrate various methods of sealing the reaction chambers according to the present invention that prevent reactants from escaping from the reaction chambers. FIG. 8A illustrates a cross section 400 of an edge 402 of a reaction chamber according to the present invention having a sliding seal 404 that is used to prevent reactants from escaping from the reaction chamber. The sliding seal 404 causes a tight tolerance between the edge 402 of the reaction chamber and the deposition chamber 1 02 that can be in the range of approximately 1 0-40 mils. In one embodiment, a Teflon O-ring can be used as the sliding seal.

[0074] FIG. 8B illustrates a cross section 450 of an edge 452 of a reaction chamber according to the present invention having a corrugated seal 454 that is used to prevent reactants from escaping from the reaction chambers. The corrugated seal 454 maintains the pressure differential between the reaction chamber and the deposition chamber 102. In another embodiment, a gas curtain is used to seal the reaction chambers to prevent reactants from escaping from the reaction chambers.

[0075] FIG. 9 illustrates a differentially pumped interface 500 that can be used to seal the reaction chambers 1 04, 1 06 (FIG. 1 ) according to the present invention that prevents reactants from escaping from the reaction chambers 1 04, 106. The differentially pumped interface 500 illustrates four separate regions having different pressures. First 502 and second regions 504 correspond to the first 1 04 and the second reaction chambers 1 06, respectively. The third region 506 corresponds to the deposition chamber 1 02. The fourth regions 508a,b correspond to regions between the first 1 04 and the second reaction chamber 106, respectively, and the deposition chamber 102.

[0076] The differentially pumped interface 500 illustrates a first 510a and second gas flow controller 51 0b that control the flow rate of precursor gas A (with carrier gas) and precursor gas B (with carrier gas) into the first region 502 (first reaction chamber 104) and the second region 504 (second reaction chamber 1 06), respectively. In some embodiments, the first and second gas flow controllers 51 0a,b are adjusted so that the pressure in regions 502, 504 is in the 1 -10 Torr range.

[0077] In one embodiment, the vacuum pump 1 14 is a molecular drag vacuum pump that maintains the third region 506 (deposition chamber 102) at a pressure that is in the

-4 10 Torr range during deposition. A second vacuum pump 51 2 is coupled to the fourth regions 508a,b. In one embodiment, the second vacuum pump 51 2 is a dry backing pump.

[0078] In one embodiment, flow control valves 51 4a,b control the pumping speed in the fourth regions 508a, b, respectively. In some embodiments, the pumping speed at the interfaces 51 6a,b between the first and second regions 502, 504 and the fourth regions 508a,b, respectively, is on the order of eight liters/second. In some embodiments, the pumping speed at the interfaces 51 8a,b between the first and second regions 502, 504, respectively, and the third region 506 is on the order of 2 liters/second. In these embodiments, the pressure in the fourth regions 508a,b is in

-2 the 1 0 Torr range. Equivalents

[0079] While the invention has been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined herein.

[0080] What is claimed is:

Claims

[cl ] An atomic layer deposition system comprising: a) a deposition chamber; b) a first reaction chamber that is positioned in the deposition chamber and that contains a first reactant species, a monolayer of the first reactant species being deposited on a substrate passing through the first reaction chamber; c) a second reaction chamber that is positioned in the deposition chamber, the second reaction chamber containing a second reactant species, a monolayer of the second reactant species being deposited on a substrate passing through the second reaction chamber; and d) a transport mechanism that transports a substrate in a path through the first reaction chamber and through the second reaction chamber at a constant transport rate, thereby depositing a film on the substrate by atomic layer deposition, wherein a shape of at least one of the first and the second reaction chambers is chosen to achieve a constant exposure of the substrate to a respective one of the first and the second reactant species when the transport mechanism transports the substrate in the path through the respective one of the first and the second reaction chamber at the constant transport rate.

[c2] The deposition system of claim l_wherein a first and a second radial edge of at least one of the first and the second reaction chambers is aligned to a center of the deposition chamber.

[c3] The deposition system of claim J_wherein at least one of the first and the second reaction chambers is formed in the shape of a trapezoid.

[c4] The deposition system of claim J urther comprising a processing region that is positioned in the deposition chamber, a surface treatment being performed on a substrate passing through the processing region.

[c5] The deposition system of claim l_wherein at least one of the first reaction chamber and the second reaction chamber comprises a plasma generator, the plasma generator generating a plasma in the at least one of the first and the second reaction chambers for plasma enhanced deposition.

[c6] The deposition system of claim J_wherein at least one of the first reaction chamber and the second reaction chamber comprises a seal that is chosen from the group comprising a sliding seal, a corrugated seal, and a gas curtain.

[c7] The deposition system of claim J_wherein at least one of the first reaction chamber and the second reaction chamber comprises a differentially pumped interface.

[c8] The deposition system of claim J_wherein the first reaction chamber comprises a first gas injection manifold and the second reaction chamber comprises a second gas injection manifold, the first and the second gas injection manifolds providing a respective one of the first and second reactant species to the first and the second reaction chambers.

[c9] The deposition system of claim J_wherein the first reaction chamber and the second reaction chamber transport relative to the substrate.

[cl O]

An atomic layer deposition system comprising: a) a deposition chamber; b) a first reaction chamber that is positioned in the deposition chamber, the first reaction chamber containing a first reactant species, a monolayer of the first reactant species being deposited on a substrate passing through the first reaction chamber; c) a second reaction chamber that is positioned in the deposition chamber, the second reaction chamber containing a second reactant species, a monolayer of the second reactant species being deposited on a substrate passing through the second reaction chamber; d) a processing region that is positioned in the deposition chamber, a surface treatment being performed on a substrate passing through the processing region; and e) a transport mechanism that transports a substrate in a path through the first reaction chamber, through the second reaction chamber, and through the processing region, thereby depositing a film on the substrate by atomic layer deposition.

[cl 1 ] The deposition system of claim 1 0 wherein a shape of at least one of the first and the second reaction chambers is chosen to achieve a constant exposure of the substrate to a respective one of the first and the second reactant species when the transport mechanism transports the substrate in the path through the respective one of the first and the second reaction chamber at a constant transport rate.

[cl 2] The deposition system of claim 1 0 wherein at least one of the first reaction chamber and the second reaction chamber comprises a plasma generator, the plasma generator generating a plasma in the at least one of the first and the second reaction region for plasma enhanced deposition.

[cl 3] The deposition system of claim 1 0 wherein at least one of the first reaction chamber and the second reaction chamber comprises a seal that is chosen from the group comprising a sliding seal, a corrugated seal, and a gas curtain.

[cl 4] The deposition system of claim 1 0 wherein at least one of the first reaction chamber and the second reaction chamber comprises a differentially pumped interface that maintains a partial pressure in the at least one of the first and the second reaction chambers.

[cl 5] The deposition system of claim 1 0 wherein the first reaction chamber comprises a first gas injection manifold and the second reaction chamber comprises a second gas injection manifold, the first and the second gas injection manifolds providing a respective one of the first and second reactant species to the first and the second reaction chambers.

[cl 6] The deposition system of claim 1 5 wherein a shape of a respective one of the first and the second gas injection manifolds is chosen to provide a substantially constant flow of reactant species as the substrate passes through a respective one of the first and the second reaction chambers.

[cl 7]

The deposition system of claim 10 wherein the processing region is formed in a shape that causes a substantially constant exposure of the surface treatment being performed on the substrate passing through the processing region.

[cl 8] The deposition system of claim 10 further comprising a plasma generator that generates a plasma in the processing region, the substrate passing through the processing region being exposed to the plasma, thereby performing the surface treatment.

[cl 9] The deposition system of claim 1 8 wherein the plasma generator comprises a magnetron that sputters a metal layer on the substrate passing through the processing region.

[c20] The deposition system of claim 1 8 wherein the plasma generator comprises a downstream plasma generator that is remotely located relative to the deposition chamber.

[c21 ] The deposition system of claim 10 further comprising an ion gun that generates an ion beam in the processing region, the ion beam striking the substrate passing through the processing region, thereby performing the surface treatment.

[c22] The deposition system of claim 10 further comprising an electron gun that generates an electron beam in the processing region, the electron beam striking the substrate passing through the processing region, thereby performing the surface treatment.

[c23] The deposition system of claim 10 further comprising an UV radiation source that generates UV radiation in the processing region, the UV radiation striking the substrate passing through the processing region, thereby performing the surface treatment.

[c24] The deposition system of claim 10 further comprising a substrate support that supports the substrate as the transport mechanism transports the substrate in the path through the first reaction chamber, through the second reaction chamber, and through the processing region.

f^c25] The deposition system of claim 1 0 wherein the first reaction chamber, the second reaction chamber, and the process chamber are transported relative to the substrate.

[c26] The deposition system of claim 10 further comprising a third and a fourth reaction chamber that are positioned in the deposition chamber.

[c27] The deposition system of claim 26 wherein the third reaction chamber contains the first reactant species and the fourth reaction chamber contains the second reactant species, a monolayer of the first reactant species being deposited on a substrate passing through the third reaction chamber and a monolayer of the second reactant species being deposited on a substrate passing through the fourth reaction chamber.

[c28] The deposition system of claim 26 wherein the third reaction chamber contains a third reactant species and the fourth reaction chamber contains a fourth reactant species, a monolayer of the third reactant species being deposited on a substrate passing through the third reaction chamber and a monolayer of the fourth reactant species being deposited on a substrate passing through the fourth reaction chamber.

[c29] The deposition system of claim 10 wherein the transport mechanism transports a substrate in the^«path at a substantially constant rate.

[c30] The deposition system of claim 10 further comprising a port for transporting a substrate into and out of the deposition chamber.

[c31 ] The deposition system of claim 10 wherein a pressure in the deposition chamber is chosen to direct reactant gas and by-product gases away from the first reaction chamber and the second reaction chamber.

[c32]

A method of atomic layer deposition, the method comprising: a) transporting a substrate through a first reaction chamber containing a first reactant species, thereby forming a monolayer of the first reactant species on the substrate; b) transporting a substrate through a second reaction chamber containing a second reactant species, thereby forming a monolayer of the second reactant species on the substrate; and c) transporting a substrate through a processing region, thereby performing a surface treatment on the substrate.

[c33] The method of claim 32 wherein the transporting the substrate through the processing region is preformed before the transporting the substrate through the first reaction chamber and before the transporting the substrate through the second reaction chamber.

[c34] The method of claim 32 wherein the transporting the substrate through the processing region is preformed after one of the transporting the substrate through the first reaction chamber and the transporting the substrate through the second reaction chamber and before the other of the transporting the substrate through the first reaction chamber and the transporting the substrate through the second reaction chamber.

[c35] The method of claim 32 wherein a substrate is transported through at least one of the first and the second reaction chambers at a substantially constant rate.

[c36] The method of claim 32 wherein the transporting the substrate through the processing region comprises exposing the substrate to a plasma.

[c37] The method of claim 32 wherein the transporting the substrate through the processing region comprises exposing the substrate to an ion beam.

[c38] The method of claim 32 wherein the transporting the substrate through the processing region comprises exposing the substrate to electron beam radiation.

[c39] The method of claim 32 wherein the transporting the substrate through the processing region comprises exposing the substrate to UV radiation.

[c40] . The method of claim 32 wherein the transporting the substrate through the processing region comprises exposing the substrate to a non-reactive gas.

[c41 ] The method of claim 32 wherein the transporting the substrate through the processing region modifies a sticking coefficient on a surface of the substrate.

[c42] The method of claim 32 wherein the transporting the substrate through the processing region activates a reaction on a surface of the substrate.

[c43] The method of claim 32 wherein the method of atomic layer deposition deposits a seed layer on the surface of the substrate for sputter deposition.

[c44] An atomic layer deposition system comprising: a) means for transporting a substrate through a first reaction chamber containing a first reactant species, thereby forming a monolayer of the first reactant species on the substrate; b) means for transporting a substrate through a second reaction chamber containing a second reactant species, thereby forming a monolayer of the second reactant species on the substrate; and c) means for transporting a substrate through a processing region, thereby performing a surface treatment on the substrate.