US20030232501A1 - Surface pre-treatment for enhancement of nucleation of high dielectric constant materials - Google Patents

Abstract

Embodiments of the present invention relate to a surface preparation treatment for the formation of thin films of high k dielectric materials over substrates. One embodiment of a method of forming a high k dielectric layer over a substrate includes pre-cleaning a surface of a substrate to remove native oxides, pre-treating the surface of the substrate with a hydroxylating agent, and forming a high k dielectric layer over the surface of the substrate. One embodiment of a method of forming a hafnium containing layer over a substrate includes introducing an acid solution to a surface of a substrate, introducing a hydrogen containing gas and an oxygen containing gas to the surface of the substrate, and forming a hafnium containing layer over the substrate.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims benefit of U.S. Provisional Patent Application Serial No. 60/388,928, filed Jun. 14, 2002, which is herein incorporated by reference.[0001]
BACKGROUND OF THE INVENTION
• 1. Field of the Invention[0002]
• Embodiments of the present invention relate to the formation of thin films of high k dielectric materials over substrates for use in manufacturing semiconductor devices, flat-panel display devices, and other electronic devices. More particularly, embodiments of the present invention relate to a surface preparation treatment for the formation of thin films of high dielectric constant materials over substrates.[0003]
• 2. Description of the Related Art[0004]
• In the field of semiconductor processing, flat-panel display processing or other electronic device processing, chemical vapor deposition has played an important role in forming films on substrates. As the geometries of electronic devices continue to shrink and the density of devices continues to increase, the size and aspect ratio of the features are becoming more aggressive, e.g., feature sizes of 0.07 microns and aspect ratios of 10 or greater are being considered. Accordingly, conformal deposition of materials to form these devices is becoming increasingly important.[0005]
• High dielectric constant materials, such as metal oxides, are one type of thin film being formed over substrates. Problems with current methods of forming metal oxide films over substrates include high surface roughness, high crystallinity, and/or poor nucleation of the formed metal oxide film.[0006]
• Therefore, there is a need for improved processes and apparatuses for forming high k dielectric materials over substrates.[0007]
SUMMARY OF THE INVENTION
• Embodiments of the present invention relate to a surface preparation treatment for the formation of thin films of high k dielectric materials over substrates. One embodiment of a method of forming a high k dielectric layer over a substrate includes pre-cleaning a surface of a substrate to remove native oxides, pre-treating the surface of the substrate with a hydroxylating agent, and forming a high k dielectric layer over the surface of the substrate. One embodiment of a method of forming a hafnium containing layer over a substrate includes introducing an acid solution to a surface of a substrate, introducing a hydrogen containing gas and an oxygen containing gas to the surface of the substrate, and forming a hafnium containing layer over the substrate.[0008]
BRIEF DESCRIPTION OF THE DRAWINGS
• So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.[0009]
• It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.[0010]
• FIG. 1 is a flow chart of one embodiment of a method of forming a high k dielectric layer over a substrate[0011]
• FIGS.[0012]2A-C are schematic cross-sectional views of one embodiment of a substrate at certain stages in the method of FIG. 1.
• FIG. 3 is a schematic cross-section view of one embodiment of a single-substrate clean chamber.[0013]
• FIG. 4 is a schematic view of one embodiment of an apparatus adapted for rapid thermal processing.[0014]
• FIG. 5 is a flow chart of one embodiment of an in-situ steam generation process.[0015]
• FIG. 6 is a schematic cross sectional view of one embodiment of a chamber capable of depositing a high k dielectric layer by chemical vapor deposition.[0016]
• FIG. 7 is a general chemical structure for one embodiment of a hafnium metal organic precursor.[0017]
• FIG. 8 is a schematic top view of one embodiment of an integrated processing system.[0018]
• FIGS.[0019]9A-9B are schematic cross-sectional views of embodiments of a hafnium containing layer comprising a plurality of layers formed over a substrate.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
• Embodiments of the present invention relate to the formation of high k dielectric materials over substrates. High k dielectric materials include hafnium containing materials, aluminum oxides, zirconium oxides, lanthanum oxides, yttrium oxides, tantalum oxides, other suitable materials, composites thereof, combinations thereof. Hafnium containing high k dielectric materials include hafnium oxides (e.g., HfO[0020]₂), hafnium silicates (e.g., HfSiO), hafnium nitrides (e.g., HfN), other suitable materials, composites thereof, and combinations thereof. The high k dielectric material preferably comprises hafnium oxides, hafnium silicates, composites thereof, or combinations thereof. Substrates include semiconductor wafers and glass substrates and may include materials formed thereover, such as dielectric materials, conductive materials, silicon layers, metal layers, etc.
• FIG. 1 is a flow chart of one embodiment of a[0021]method100 of forming a high k dielectric layer over a substrate. Instep110, the surface of a substrate is pre-cleaned to remove native oxides which may have formed over the surface of the substrate. Instep120, the surface of the substrate is pre-treated with a hydroxylating agent to perform a controlled hydroxylation of the substrate. Instep130, a high k dielectric layer is formed thereover.
• Not wishing to be bound by theory unless explicitly set forth in the claims, FIGS.[0022]2A-C are schematic cross-sectional views of one embodiment of asilicon substrate200 at certain stages in themethod100 of FIG. 1. For clarity of description, themethod100 will be described in reference to formation of a high k dielectric layer comprising a hafnium containing layer.
• FIG. 2A shows the[0023]substrate200 after the surface of the substrate is pre-cleaned to remove native oxides which may have formed over the substrate surface. It is believed that the pre-clean leaves the surface of a substrate with a silicon-hydrogen (Si—H)surface212. FIG. 2B shows thesubstrate200 after the surface of the substrate is pre-treated with a hydroxylating agent. It is believed that the hydroxylating agent converts the Si—H surface212 of FIG. 2A into a silicon-hydroxy (Si—O—H)surface214. FIG. 2C shows thesubstrate200 after ahafnium containing layer216, such as a hafnium oxide layer, has been formed over the surface of the substrate.
• The[0024]hafnium containing layer216 can comprise a single layer or a plurality of layers. If thehafnium containing layer216 is made of a plurality of layers, each layer may be a different type of hafnium containing material, the same type of hafnium containing material, or combinations thereof. For example, FIG. 9A is a schematic cross-sectional view of one embodiment of a hafnium containing layer comprising a hafnium silicate material layer formed over a hafnium oxide material layer. In another example, FIG. 9B is a schematic cross-sectional view of one embodiment of a hafnium containing layer comprising a plurality of hafnium silicate layers. Each hafnium silicate layer may comprise the same or different proportions of hafnium, silicon, and oxygen atoms.
• In reference to FIGS.[0025]2A-C, it is believed that during formation of thehafnium containing layer216 aninterfacial layer215 comprising hafnium silicates is formed between thehafnium containing layer216 and thesubstrate200. It is believed that in formation of thehafnium containing layer216, less energy is required to break the bonds of the Si—O—H surface214 of FIG. 2B to form thehafnium containing layer216 than directly breaking the bonds of the Si—H surface212 of FIG. 2A. In addition, the extent of hydroxylation of the surface of the substrate can be controlled, as opposed to hydroxylation by the atmosphere (native oxides), and the thickness of theinterfacial layer215 can be reduced.
• It has been observed that a hafnium containing layer formed by the methods disclosed herein has improved film characteristics. The formed hafnium containing layer is amorphous and may be formed over a substrate with minimal formation of an[0026]interfacial layer215, such as an interfacial layer having a thickness about 13 Å or less, more preferably about 6 Å or less. In addition, the formed hafnium containing layer has improved nucleation (less islands) over a substrate surface. In certain embodiments, a hafnium containing layer may be formed to a surface roughness (Rms) of less than about 4 Å, preferably less than about 3 Å, and more preferably about 2.55 Å or less.
• Pre-Clean[0027]
• Referring to step[0028]110 of FIG. 1, pre-cleaning of a substrate surface may be performed by contacting the substrate surface with a cleaning solution in a batch clean system, in a single-substrate clean system, or any other suitable clean system. One example of a single-substrate clean system is an OASIS CLEAN™ system available from Applied Materials, Inc. of Santa Clara, Calif. The cleaning solution may be a RCA-type cleaning solution or any other suitable cleaning solution which removes native oxides, which may have formed over the substrate surface, and may involve single-step chemistry or multi-step chemistries. The substrate surface may be contacted with the cleaning solution for a specified time period.
• FIG. 3 is a schematic cross-section view of one embodiment of a single-substrate[0029]clean chamber300 which may be part of a multi-chamber system. Thechamber300 includes aplatter308 with a plurality of acoustic orsonic transducers302 located thereon. Thetransducers302 are attached to the bottom surface ofplatter308. Thetransducers302 create acoustic or sonic waves directed towards the surface of asubstrate306.
• The[0030]substrate306 is held at a distance above the top surface ofplatter308. Thesubstrate306 is clamped by a plurality ofclamps310 face up and can rotate or spinsubstrate306 about it's the substrate's central axis. Inchamber300, theclamps310 andsubstrate306 are rotated during use whereasplatter308 remains in a fixed position. Additionally, inchamber300,substrate306 is placed face up and the backside of the substrate facesplatter308, i.e., the side of the substrate with patterns or features faces towards one ormore nozzles351 which spray cleaning or etching chemicals thereon.
• During use, deionized water (Dl water) is fed through a feed through[0031]channel328 andplatter308 and fills the gap between the backside ofsubstrate306 andplatter308 to provide a water filledgap318 through which acoustic waves generated bytransducers302 can travel tosubstrate306.
• Additionally during use, cleaning solutions such as SC-1 and SC-2, etchants such as diluted hydrofluoric acid or buffered hydrofluoric acid, and rinsing water such as deionized water are fed through a plurality of[0032]nozzles351 to the top surface of thesubstrate306 while thesubstrate306 is spun.Tanks323 containing wet processing chemicals such as diluted hydrofluoric acid, de-ionized water, and cleaning solutions are coupled byconduit354 tonozzles351.
• Other aspects and embodiments of a single-substrate clean system are disclosed in U.S. patent application Ser. No. 09/891,849, entitled “Method and Apparatus for Wafer Cleaning, filed Jun. 25, 2001 and in U.S. patent application Ser. No. 09/891,791, entitled “Wafer Spray Configurations for a Single Wafer Processing Apparatus,” filed Jun. 25, 2001, both of which are herein incorporated by reference in their entirety to the extent not inconsistent with the present disclosure.[0033]
• One embodiment of the step[0034]110 (FIG. 1) of pre-cleaning the substrate surface, which may be performed in the apparatus as described in reference to FIG. 3 or may be performed in other batch clean systems or single-substrate clean systems, comprises introducing a dilute hydrofluoric acid solution onto the substrate surface for a suitable time period, such as between about 5 seconds and about 1 hour or more, preferably between about 1 minute and about 15 minutes, more preferably about 2 minutes. Any suitable concentration of hydrofluoric acid may be used, preferably between about 1 weight percent and about 49 weight percent hydrofluoric acid, more preferably about 2 weight percent hydrofluoric acid. After introduction of a hydrofluoric acid solution to the substrate, the substrate surface is referred to a HF-last surface.
• Pre-Treatment[0035]
• Referring to FIG. 1, one embodiment of[0036]step120 of pre-treating the substrate surface with a hydroxylating agent comprises contacting the surface of the substrate with water vapor generated in a flash in-situ steam generation (ISSG) process. In other embodiments, the hydroxylating agent be other suitable compounds. The pre-treatment of the present invention can be carried out in a rapid thermal heating apparatus, such as, but not limited to, the RTP XE chamber, available from Applied Materials, Inc. of Santa Clara, Calif. One embodiment of a rapid thermal heating apparatus is disclosed in U.S. Pat. No. 6,037,273, entitled “Method and Apparatus for Insitu Vapor Generation,” assigned to Applied Materials, Inc. of Santa Clara, Calif., which is a Continuation-In-Part Application to U.S. patent application Ser. No. 08/893,774, both of which are incorporated by reference in their entirety to the extent not inconsistent with the present disclosure. Another suitable rapid thermal heating apparatus and its method of operation is set forth in U.S. Pat. No. 5,155,336, entitled “Rapid Thermal Heating Apparatus and Method,” filed Oct. 24, 1991, which is herein incorporated by reference in its entirety to the extent not inconsistent with the present disclosure. Additionally, other types of thermal reactors may be utilized such as the Epi or Poly Centura single wafer “cold wall” reactor by Applied Materials, Inc. of Santa Clara, Calif.
• FIG. 4 is a schematic view of one embodiment of an[0037]apparatus400 adapted for rapid thermal processing. Theapparatus400 includes an evacuatedprocess chamber413 enclosed by asidewall414 and abottom wall415. A radiant energylight pipe assembly418 is positioned over and coupled towindow assembly417. The radiant energylight pipe assembly418 includes a plurality oftungsten halogen lamps419 each mounted into alight pipe421.Lamps419 are positioned to adequately cover the entire surface area ofsubstrate461. Awindow assembly417 may be disposed below thelight pipe assembly418.
• A[0038]substrate461 is supported insidechamber413 by asupport ring462 which engages the substrate near its edge.Support ring462 is mounted on arotatable quartz cylinder463. By rotatingquartz cylinder463,support ring462 andwafer461 can be caused to rotate.
• The[0039]bottom wall415 ofapparatus400 includes a coatedtop surface411 for reflecting energy onto the backside ofwafer461. Additionally, rapidthermal heating apparatus400 includes a plurality of fiber optic probes470 positioned through thebottom wall415 ofapparatus400 in order to detect the temperature ofsubstrate461 at a plurality of locations across its bottom surface.
• Rapid[0040]thermal heating apparatus400 includes agas inlet469 formed throughsidewall414 for injecting process gas intochamber413 to allow various processing steps to be carried out inchamber413. Coupled togas inlet469 are one or more gas sources. Positioned on the opposite side ofgas inlet469, insidewall414, is agas outlet468.Gas outlet468 is coupled to a vacuum source, such as a pump, to exhaust process gas fromchamber413 and to reduce the pressure inchamber413. The vacuum source maintains a desired pressure while process gas is fed into the chamber during processing.
• FIG. 5 is a flow chart of one embodiment of an[0041]ISSG process500. The ISSG process may be performed in any suitable chamber. For clarity of description, theISSG process500 will be described in reference tosubstrate processing apparatus400 as described in FIG. 4 and will be described in reference to a 200 mm diameter substrate. The process conditions may vary depending on the apparatus used and the size of the substrate.
• In[0042]step510 of theprocess500, thesubstrate461 is moved into thechamber413. Thesubstrate461 is generally transferred into thechamber413 having a non-reactive gas ambient, such as a nitrogen (N₂) ambient, at a transfer pressure between about 1 mtorr and about 100 torr, preferably between about 1 torr and about 10 torr.Chamber413 is then sealed. Thechamber413 may be evacuated to a pressure to remove the nitrogen ambient.
• In[0043]step520, thesubstrate461 is heated or is ramped to a process temperature by applying power tolamps419. The process temperature may be any suitable temperature, such as between about 400° C. and about 1250° C., preferably between about 700° C. and about 900° C., more preferably between about 775° C. and about 825° C. During at least a portion ofstep520, a non-reactive gas, such as helium gas or nitrogen gas, may be introduced into the chamber. It is believed that the non-reactive gas acts as a thermal conductor and helps to improve temperature uniformity. Preferably, the non-reactive gas which is used is helium gas introduced at a flow rate between about 0.1 μm and about 10 slm, preferably about 1 slm. Not wishing to be bound by theory unless explicitly set forth in the claims, it is believed that helium is a better thermal conductor than N₂. In addition or alternatively, one or more process gases may be introduced during the ramp. Preferably, a hydrogen containing gas is introduced, such as a hydrogen (H₂) gas, at a flow rate between about 1 sccm and 20 sccm, preferably about 5 sccm.
• In[0044]step530, at the desired process temperature, a hydrogen containing gas and an oxygen containing gas are introduced to thechamber413. The hydrogen containing gas and the oxygen containing gas are introduced to be reacted together to form water vapor (H₂O) at the desired process temperature. The hydrogen containing gas is preferably hydrogen gas (H₂), but may be other hydrogen containing gases such as, but not limited to, ammonia (NH₃), deuterium, and hydrocarbons, such as methane (CH₄). The oxygen containing gas is preferably nitrous oxide (N₂O), but may be other types of oxygen containing gases such as but not limited to oxygen gas (O₂). It is believed that N₂O provides a more controlled hydroxylation of the substrate surface in comparison to the use of O₂which is more reactive than N₂O. A non-reactive gas, such as helium gas, nitrogen gas, or other non-reactive gases, may be introduced duringstep530. It is believed that the non-reactive gas acts as a thermal conductor to help improve temperature uniformity. In addition or alternatively, it is believed that a non-reactive acts to catalyze the in-situ steam generation process by isolating reaction fragments. A helium non-reactive gas is preferred over a nitrogen non-reactive gas because it is believed that the helium non-reactive gas is a better thermal conductor and better at catalyzing the ISSG process.
• The hydrogen containing gas and the oxygen containing gas may be introduced at any suitable chamber pressure, such as between about 0.1 Torr and about 200 Torr, preferably between about 1 Torr and about 20 Torr. Any concentration ratio of hydrogen containing gas and oxygen containing gas may be used. Preferably, a high ratio of oxygen containing gas to hydrogen containing gas is used. For example, a process gas mixture comprising a ratio of oxygen containing gas to hydrogen containing gas is preferably between about 65:35 and about 99.9:0.1, preferably about 99.5:0.5.[0045]
• The desired process temperature causes the hydrogen containing gas and oxygen containing gas to react to form moisture or steam (H[0046]₂O). Since rapidthermal heating apparatus400 is a “cold wall” reactor, the only sufficiently hot surfaces inchamber413 to initiate the reaction is thesubstrate461 andsupport ring462. As such, the moisture generating reaction occurs near the surface ofsubstrate461. Since it is the temperature of the substrate (and support ring) which initiates or turns “on” the moisture generation reaction, the reaction is said to be thermally controlled by the temperature of wafer461 (and support ring462). Additionally, the vapor generation reaction is said to be “surface catalyzed” because the heated surface of the substrate is necessary for the reaction to occur.
• The hydrogen containing gas and the oxygen containing gas are introduced at a process temperature for a sufficient period of time to enable the water vapor generated from the reaction of the hydrogen containing gas and the oxygen containing gas to hydroxylate the substrate surface. The[0047]substrate461 will typically be held at process temperature for a time period between about 1 minute and about 1 second or less, preferably for a time period of about 10 seconds or less. Process time and temperature are generally dictated by amount of hydroxylation desired and the type and concentrations of the process gases.
• In[0048]step540, power tolamps419 is reduced or turned off to reduce or ramp down the temperature ofsubstrate461. Simultaneously, a purge gas, such as nitrogen gas (N₂), is fed into the chamber13 to remove residual process gases. Then, thesubstrate461 may be removed from thechamber413.
• Although the present invention has been described with respect to in-situ generation of a vapor of a specific reactive species, water, it is to be appreciated that the teachings of the present invention can be applied to other processes where the temperature of a substrate is used to initiate or catalyze the reaction of reactant gases to form a vapor of a reactive species near the wafer surface. The reactive species vapor can then be reacted with the wafer or with films formed thereon to carry out processes such as film growth. For example, a reactant gas mixture comprising ammonia (NH[0049]₃) and oxygen (O₂) can be fed into a chamber and then caused to react by heating a wafer to a sufficient temperature to initiate a reaction of the gases to form an oxy-nitride surface. High K Dielectric Layer Formation
• Referring to step[0050]130 of FIG. 1, a high k dielectric layer may be formed by chemical vapor deposition (including metal-organic chemical vapor deposition, low pressure chemical vapor deposition, plasma-enhanced chemical vapor deposition), atomic layer deposition (ALD), physical vapor deposition, vapor phase epitaxy (VPE), other suitable deposition techniques, and combination of deposition techniques.
• One embodiment of a chamber capable to deposit a high k dielectric layer by MOCVD is disclosed in U.S. patent application Ser. No. 09/179,921, which is incorporated by reference in its entirety to the extent not inconsistent with the present disclosure.[0051]
• FIG. 6 is a schematic cross sectional view of one embodiment of a[0052]chamber600 capable of depositing a high k dielectric layer, such as hafnium containing layer, by MOCVD.Chamber body610 andheated chamber lid605, which is hingedly connected tochamber body610, together form aprocessing region602 is bounded byshowerhead640,substrate support650, and the walls ofchamber body610. Substrate support650 (shown in the raised position for processing) extends through the bottom ofchamber body610. Aslit valve615 allows substrates to be transferred to and from theprocessing region602.
• Imbedded within[0053]substrate support650 is a resistive heater. A thermocouple in thermal contact withsubstrate support650 may sense the temperature ofsubstrate support650 to allow for temperature control ofheated substrate support650.Substrate601 is supported by the upper surface ofsupport650 and is heated by the resistive heaters withinsubstrate support650 to processing temperatures.
• Turning now to gas delivery features of[0054]chamber600, process gases are introduced viaconduit673, throughcentral bore630 and flow throughblocker plate637 andshowerhead640 intoprocessing region602. Pumpingpassage603 andoutlet port660 formed withinchamber body610 remove process gas and by-products of processing operations conducted withinprocessing region602.
• For illustration purposes, deposition of a high k dielectric layer will be described in reference to MOCVD of a hafnium oxide layer. Metal-organic CVD of hafnium oxide comprises introducing a hafnium organic precursor and introducing an oxygen containing compound to the chamber, such as[0055]chamber600 of FIG. 6. Examples of a hafnium organic precursor include the compound having the structure of M(NRR′)₄shown in FIG. 7, wherein at least one of R and R′ is as follows:
• R=H, CH[0056]₃, C₂H₅, C₃H₇, CO, NCO, alkyl, and aryl and
• R=H, CH[0057]₃, C₂H₅, C₃H₇, CO, NCO, alkyl, and aryl.
• R and R′ may or may not be the same. Preferably, both R and R′ are an alkyl group having one to four carbon atoms, and more preferably are the same alkyl group. Examples of preferred hafnium organic precursors include tetrakis(diethylamido)hafnium (TDEAH) and tetrakis (dimethylamido)hafnium, and most preferably is TDEAH. Examples of an oxygen containing compound include oxygen gas (O[0058]₂). Other oxygen containing compounds may also be used, such as ozone, H₂O, N₂O, atomic oxygen (i.e. oxygen plasma).
• One embodiment of a process for depositing hafnium oxide by MOCVD will be described in reference to a 200 mm diameter substrate. The process conditions may vary depending on the apparatus used and the size of the substrate. One embodiment of depositing hafnium oxide comprises flowing TDEAH onto the substrate surface at a rate between about 1 mg/min and about 50 mg/min, preferably about 7 mg/min, O[0059]₂is flowed onto the wafer surface between about 30 sccm and about 3,000 sccm, preferably 1,000 sccm, and N₂is flowed onto the wafer surface at a rate between about 30 sccm and about 3,000 sccm, preferably about 1,500 sccm. O₂, N₂and TDEAH are introduced onto the wafer surface either simultaneously, sequentially, or a combination thereof.
• The hafnium oxide layer is formed at temperatures in the range between about 225° C. and about 700° C. Preferably, the hafnium oxide layer is formed at about 485° C. The pressure in the deposition chamber is in the range between about 1.5 Torr and about 8 Torr, preferably about 4 Torr. The process may be performed for a specified time period, preferably about 60 seconds or less. Preferably, the hafnium oxide layer formed has a thickness between about 20 Å and about 50 Å, preferably about 40 Å or less.[0060]
• Processing System[0061]
• The processes in the formation of a high k dielectric layer as disclosed herein may be carried out in one or more single chamber systems, one or more mainframe systems having a plurality of chambers, and combinations thereof. The processes may be performed in separate processing systems or an integrated processing system.[0062]
• FIG. 8 is a schematic top view of one embodiment of an[0063]integrated system800 capable of performing the processes disclosed herein. Theintegrated system800 comprises acleaning module810 and a thermal processing/deposition mainframe system830. As shown in the figure, thecleaning module810 is an OASIS CLEAN™ system, available from Applied Materials, Inc., located in Santa Clara, Calif. The thermal processing/deposition mainframe system830 is a CENTURA® system and is also commercially available from Applied Materials, Inc., located in Santa Clara, Calif. The particular embodiment of the system to perform the process as disclosed herein is provided to illustrate the invention and should not be used to limit the scope of the invention unless otherwise set forth in the claims.
• The[0064]cleaning module810 generally includes one ormore substrate cassettes812, one ormore transfer robots814 disposed in a substrate transfer region, and one or more single-substrateclean chambers816. The single-substrateclean chambers816 may be similar to chamber described in reference to FIG. 3.
• The thermal processing/[0065]deposition mainframe system830 generally includesload lock chambers832, atransfer chamber834, andprocessing chambers836A,836B,836C,836D. Theload lock chambers832 allow for the transfer of substrates into and out from the thermal processing/deposition mainframe system830 while thetransfer chamber834 remains under a low pressure non-reactive environment. The transfer chamber includes arobot840 having one or more blades which transfers the substrates between theload lock chambers832 andprocessing chambers836A,836B,836C,836D. Any of theprocessing chambers836A,836B,836C,836D may be removed from the thermal processing/deposition mainframe system830 if not necessary for the particular process to be performed by thesystem830. The transfer region is preferably between 1 mtorr to about 100 torr and preferably comprises a non-reactive gas ambient, such as a N₂ambient.
• It is believed that it is advantageous to perform the pre-treatment step[0066]120 (FIG. 1) and the high k dielectric layer formation130 (FIG. 1) on a mainframe system to reduce the formation of native oxides and/or contamination of the pre-treated surface of a substrate prior to formation of the high k dielectric layer. Exposing the substrate to air between thepre-treatment step120 and the high kdielectric layer formation130 may reduce the effectiveness of nucleation thereover of high k dielectric materials. It is optional to have thecleaning module810 coupled withmainframe system830 as shown in FIG. 8 to further reduce the formation of native oxides over and/or contamination of substrates between cleaning steps and other processing steps. Of course, I n other embodiments, cleaning steps may be performed in a cleaning module separate from the thermal processing/deposition mainframe system.
• One embodiment of the[0067]integrated system800 configured to form a high k dielectric layer comprisesprocessing chamber836B adapted to perform an ISSG process as described above and aprocessing chamber836C, such as a chemical vapor deposition chamber or an atomic layer deposition chamber, adapted to deposit a high dielectric constant material, such as a hafnium containing layer. Other embodiments of thesystem800 are within the scope of the present invention. For example, the position of a particular processing chamber on the system may be altered.
EXAMPLES
• Various samples of silicon substrates were processed. Each silicon substrate comprised 200 mm diameter wafers.[0068]
Comparative Example 1
• [0069]Sample 1 was pre-cleaned using a hydrofluoric acid solution to form a HF-last surface. A layer of hafnium oxide was deposited by MOCVD to a thickness of about 40 Å over the substrate surface at a temperature of about 325° C. The roughness of the hafnium oxide surface ofSample 1 was measured to have a Rms (nm) of 0.580, a Ra (nm) of 0.45 and a Rmax (nm) of 10.01.
Example 2
• Samples 2-5 were pre-cleaned using a hydrofluoric acid solution to form a HF-last surface. Thereafter, Samples 2-5 were pre-treated with a rapid thermal oxidation (RTO) process in an O[0070]₂ambient.Sample 2 was pre-treated with a RTO process at a temperature of about 900° C. for a time period of about 10 seconds. Sample 3 was pre-treated with a RTO process at a temperature of about 900° C. for a time period of about 5 seconds. Sample 4 was pre-treated with a RTO process at a temperature of about 850° C. for a time period of about 10 seconds. Sample 5 was pre-treated with a RTO process at a temperature of about 850° C. for a time period of about 5 seconds. A layer of hafnium oxide was deposited by MOCVD over the substrate surface to a thickness of about 40 Å at a temperature of about 325° C. over each of the Samples 2-5. The roughnesses of the hafnium oxide surfaces of Samples 2-5 were measured and are shown below in Table 1. Samples 2-5 had lower surface roughnesses in comparison toSample 1.

  	TABLE 1
  	Rms (nm)	Ra (nm)	Rmax (nm)

  	Sample 2	0.386	0.306	3.724
  	Sample 3	0.387	0.307	3.812
  	Sample 4	0.394	0.313	3.678
  	Sample 5	0.393	0.311	3.882

Example 3
• Sample 6 was pre-cleaned using a hydrofluoric acid solution to form a HF-last surface. Thereafter, Sample 6 was pre-treated with an oxygen (O[0071]₂) soak. A layer of hafnium oxide was deposited by MOCVD to a thickness of about 40 Å over the substrate surface at a temperature of about 325° C. The roughness of the hafnium oxide surface of Sample 6 was measured to have a Rms (nm) of 0.714, a Ra (nm) of 0.567, and a Rmax (nm) of 6.618. Samples 6 had a higher surface roughness in comparison toSample 1.
Example 4
• Samples 7-9 were pre-treated with a high dose decoupled plasma nitridation. Thereafter, for Sample 7, a layer of hafnium oxide was deposited by MOCVD to a thickness of about 40 Å over the substrate surface at a temperature of about 325° C. Sample 8 was cleaned using a hydrofluoric acid solution to form a HF-last surface and a layer of hafnium oxide was deposited by MOCVD to a thickness of about 40 Å over the substrate surface at a temperature of about 325° C. Sample 9 was cleaned using a hydrofluoric acid solution to form a HF-last surface and treated with a rapid thermal oxidation process at a temperature about 900° C. The roughnesses of the surfaces of the Samples 7-9 were measured and are shown in Table 2. Note that a layer of hafnium oxide was not deposited over Sample 9. Sample 7 had a slightly higher surface roughness in comparison to[0072]Sample 1 while Sample 8 had a slightly lower surface roughness in comparison toSample 1.

  	TABLE 2
  	Rms (nm)	Ra (nm)	Rmax (nm)

  	Sample 7	0.611	0.483	5.439
  	Sample 8	0.539	0.425	4.899
  	Sample 9	0.265	0.209	2.680

Example 5
• Samples 10-12 were pre-treated with a low dose decoupled plasma nitridation process. Thereafter, for[0073]Sample 10, a layer of hafnium oxide was deposited by MOCVD to a thickness of about 40 Å over the substrate surface at a temperature of about 325° C. Sample 11 was cleaned using a hydrofluoric acid solution and a layer of hafnium oxide was deposited by MOCVD to a thickness of about 40 Å at a temperature of about 325° C. Sample 12 was pre-cleaned using a hydrofluoric acid solution to form a HF-last surface and treated with a rapid thermal oxidation process at a temperature of about 900° C. Then, for Sample 12, a layer of hafnium oxide was deposited by MOCVD to a thickness of about 40 Å over the substrate surface at a temperature of about 325° C. The roughnesses of the hafnium oxide surface of Samples 10-12 were measured and are shown below in Table 3.Sample 10 had a slightly higher surface roughness in comparison toSample 1 while Sample 11 had a slightly lower surface roughness in comparison toSample 1 and while Sample 12 had a lower surface roughness in comparison toSample 1.

  	TABLE 3
  	Rms (nm)	Ra (nm)	Rmax (nm)

  	Sample 10	0.593	0.470	5.521
  	Sample 11	0.573	4.455	4.971
  	Sample 12	0.266	0.210	2.773

Example 6
• Samples 13-15 were pre-cleaned using a hydrofluoric acid solution to form a HF-last surface. Thereafter, Samples 13-15 were pre-treated with an ISSG process utilizing H[0074]₂gas and N₂O gas. Sample 13 was pre-treated in the ISSG process for a time period of about 4 seconds. Sample 14 was pre-treated in the ISSG process for a time period of about 6 seconds. Sample 15 was pre-treated in the ISSG process for a time period of about 8 seconds. A layer of hafnium oxide was deposited by MOCVD over the substrate surface to a thickness of about 40 Å at a temperature of about 325° C. over each of the Samples 13-15. The roughnesses of the hafnium oxide surface of Samples 13-15 were measured and are shown below in Table 4. Samples 13-15 had much lower surface roughnesses in comparison toSample 1.

  	TABLE 4
  	Rms (nm)	Ra (nm)	Rmax (nm)

  	Sample 13	0.255	0.201	2.688
  	Sample 14	0.262	0.206	2.654
  	Sample 15	0.260	0.204	2.498

• While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.[0075]

Claims (41)

1. A method of forming a high dielectric constant layer over a substrate, comprising:

pre-cleaning a surface of a substrate to remove native oxides;

pre-treating the surface of the substrate with an hydroxylating agent; and

forming a high dielectric constant layer over the surface of the substrate.

2. The method ofclaim 1, wherein pre-cleaning comprises introducing an acid solution to the surface of the substrate.

3. The method ofclaim 2, wherein the acid solution comprises a hydrofluoric acid solution.

4. The method ofclaim 1, wherein the hydroxylating agent comprises water vapor.

5. The method ofclaim 4, wherein a water vapor is generated from a hydrogen containing gas and an oxygen containing gas.

6. The method ofclaim 5, wherein the hydrogen containing gas is hydrogen (H₂) gas and wherein the oxygen containing gas is nitrous oxide (N₂O) gas.

7. The method ofclaim 1, wherein the high dielectric constant layer comprises a material selected from the group including hafnium containing materials, aluminum oxides, zirconium oxides, lanthanum oxides, yttrium oxides, tantalum oxides, composites thereof, and combinations thereof.

8. The method ofclaim 1, wherein the high dielectric constant layer comprises a material selected from the group including hafnium oxides, hafnium silicates, hafnium nitrides, hafnium aluminates, hafnium silicon oxynitrides, composites thereof, and combinations thereof.

9. The method ofclaim 1, wherein the high dielectric constant layer comprises hafnium oxides, compositions thereof, or combinations thereof.

10. The method ofclaim 1, wherein the high dielectric constant layer comprises hafnium silicates, composites thereof, or combinations thereof.

11. The method ofclaim 1, wherein forming the high dielectric constant layer comprises introducing a metal precursor and an oxygen containing compound.

12. The method ofclaim 1, wherein forming the high dielectric constant layer comprises a deposition technique selected from the group comprising chemical vapor deposition, atomic layer deposition, and physical vapor deposition.

13. A method of forming a hafnium containing layer over a substrate, comprising:

introducing an acid solution to a surface of a substrate;

introducing a hydrogen containing gas and an oxygen containing gas to the surface of the substrate; and

forming a hafnium containing layer over the substrate.

14. The method ofclaim 13, wherein the hafnium containing layer comprises a material selected from the group including hafnium oxides, hafnium silicates, hafnium nitrides, hafnium aluminates, hafnium silicon oxynitrides, composites thereof, and combinations thereof.

15. The method ofclaim 13, wherein the hafnium containing layer comprises hafnium oxides, composites thereof, or combinations thereof.

16. The method ofclaim 13, wherein the hafnium containing layer comprises hafnium silicates, composites thereof, or combinations thereof.

17. The method ofclaim 13, wherein the acid solution comprises a hydrofluoric acid solution.

18. The method ofclaim 13, wherein the hydrogen containing gas is hydrogen (H₂) gas and wherein the oxygen containing gas is nitrous oxide (N₂O) gas.

19. The method ofclaim 13, wherein the ratio of oxygen containing gas to hydrogen containing gas is between about 65:35 and about 99.9:0.1.

20. The method ofclaim 13, further comprising introducing a non-reactive gas during the step of introducing a hydrogen containing gas and an oxygen containing gas.

21. The method ofclaim 20, wherein the non-reactive gas comprises helium gas.

22. The method ofclaim 13, wherein the substrate is at a temperature between about 400° C. and about 1,250° C. during the step of introducing a hydrogen containing gas and an oxygen containing gas.

23. The method ofclaim 13, wherein the substrate is at a temperature between about 700° C. and about 900° C. during the step of introducing a hydrogen containing gas and an oxygen containing gas.

24. The method ofclaim 13, wherein the hydrogen containing gas and the oxygen containing gas are introduced to the surface of the substrate for a time period of about 1 minute or less.

25. The method ofclaim 13, wherein the hydrogen containing gas and the oxygen containing gas are introduced to the surface of the substrate for a time period of about 10 seconds or less.

26. The method ofclaim 13, wherein forming a hafnium containing layer comprises introducing a hafnium precursor and an oxygen containing compound.

27. A structure, comprising:

a substrate;

an interfacial layer formed over the substrate, the interfacial layer having a thickness of about 13 Å or less; and

one or more hafnium containing layers formed over the interfacial layer.

28. The structure ofclaim 27, wherein the interfacial layer has a thickness of about 6 Å or less.

29. The structure ofclaim 27, wherein the hafnium containing layer is amorphous.

30. The structure ofclaim 27, wherein the hafnium containing layer has a surface roughness (Rms) of about 0.4 nm or less.

31. The structure ofclaim 27, wherein the hafnium containing layer has a surface roughness (Rms) of about 0.3 nm or less.

32. The structure ofclaim 27, wherein the one or more hafnium containing layers are formed to a combined thickness of about 50 Å or less.

33. The structure ofclaim 27, wherein the hafnium containing layer is formed to a thickness of about 40 Å or less.

34. An integrated system for forming a hafnium containing high dielectric constant layer over a substrate, comprising:

one or more rapid thermal processing chambers adapted to generate steam by introducing a hydrogen containing gas and an oxygen containing gas;

one or more deposition chambers adapted to deposit a hafnium containing layer;

a transfer chamber in communication with the rapid thermal processing chambers and the deposition chambers; and

one or more load lock chambers.

35. The system ofclaim 34, wherein the rapid thermal processing chambers are adapted to introducing hydrogen (H₂) gas and nitrous oxide (N₂O) gas to generate steam.

36. The system ofclaim 34, wherein the deposition chambers are adapted to form a hafnium containing layer by introducing a hafnium precursor and an oxygen containing gas.

37. The system ofclaim 34, further comprising a cleaning module in communication with the load lock chambers.

38. The system ofclaim 37, wherein the cleaning module comprises one or more single-substrate clean chambers.

39. A method of forming a hafnium containing layer on a substrate, comprising:

remove native oxides from a surface of the substrate;

hydroxylating the surface of the substrate to form a hydroxylated surface; and

forming a hafnium containing layer over the hydroxylated surface.

40. The method ofclaim 39, wherein forming a hafnium containing layer comprises forming an interfacial layer to a thickness of about 13 Å or less.

41. The method ofclaim 39, wherein forming a hafnium containing layer comprises forming an interfacial layer to a thickness of about 6 Å or less.

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