TW201034078A - Methods for forming conformal oxide layers on semiconductor devices - Google Patents

Abstract

Methods and apparatus for forming an oxide layer on a semiconductor substrate are disclosed. In one or more embodiments, plasma oxidation is used to form a conformal oxide layer by controlling the temperature of the semiconductor substrate at below about 100 DEG C. Methods for controlling the temperature of the semiconductor substrate according to one or more embodiments include utilizing an electrostatic chuck and a coolant and gas convection.

Description

201034078 VI. Description of the Invention: [Technical Field] The present invention relates generally to semiconductor fabrication and, more particularly, to oxidation of a semiconductor device or its components to form a conformal oxide layer. . [Prior Art] • A semiconductor device needs to form a thin oxide layer at several stages of its fabrication. For example, a thin gate oxide layer can be formed as part of a gate stack structure, including sidewalls, as will be described later. Further, in some applications, such as in the fabrication of a flash memory film stack, a thin oxide layer can be formed around the entire gate stack, for example, by exposing the stack to an oxidizing process. Such oxidation processes are conventionally performed by thermal methods or by slurry processing. The thermal process of forming an oxide layer, e.g., the gate oxide layer or the gate stack oxide layer, works reasonably well in the fabrication of larger feature size semiconductor devices used in the past. Unfortunately, as feature sizes shrink dramatically and different oxides are used in next-generation advanced technologies, the high wafer or substrate temperature required for thermal oxidation processes can be due to dopants in the germanium wafer (well doping and The joint surface) diffuses at higher temperatures (e.g., above about 7 〇〇 °c) causing problems. Distortion of such dopant profiles and other features can result in poor device performance or failure. The plasma process used to form the oxide layer has similar problems. For example, 201034078 under south chamber pressure (eg, 1 GG mTorr), the tendency of contaminants to converge within the gate oxide layer during formation, causing serious defects in the gate oxide structure, such as dangling b 〇nds) or moving charges, under low chamber pressure (eg, tens of millitors), increased electrical ion energy causes ion bombardment damage and other diffusion problems. For example, conventional oxidation processes often cause defects known as bird's beak. A bird's beak refers to an oxide layer that diffuses from the sides at the interface between adjacent layers into the layers of the film stack to surround the corners of the adjacent layers. The resulting defect has a beak-like wheel. The active region of the oxide layer invading the memory cell (eg, in a flash memory application) reduces the active width of the memory cell, and thus is not expected to reduce the effective width of the cell, and Reduce the performance of the flash memory device. Another limitation of the current low zm plasma process is that oxidation appears to occur preferentially on the surface parallel to the wafer or substrate surface, that is, the top and bottom of the structure, such as the gate formed by stacking layers of material a pole and a trench formed between the gates. This is due to the oxygen ion and free radical flux perpendicular to the wafer. Regardless of the cause, limited oxidation occurs on the side walls of the stack, resulting in an unacceptable sidewall layer and poor conformality on the gate stack. Therefore, there is a need for an improved method of forming an oxide layer on a semiconductor substrate. SUMMARY OF THE INVENTION One aspect of the present invention is directed to a method of processing an oxide layer formed on a semiconductor substrate. In accordance with one or more embodiments, the method 201034078 includes placing such a substrate on a substrate support within a plasma reaction chamber. The chamber used in one or more embodiments includes an ion generating region. The method may also include introducing or flowing a process gas into the chamber, wherein in the ion generating region, a plasma is generated in the ion generating region of the chamber and used to form on the substrate. An oxide layer. The plasma formed in accordance with one or more embodiments may contain oxygen or an oxygen species. In one or more embodiments, the oxide layer is formed from the plasma during active cooling of the substrate. In this embodiment, actively cooling the substrate increases the viscosity coefficient of the oxygen species contained in certain plasmas. According to one or more embodiments, the substrate is cooled to a temperature of less than about 1 〇〇 ° C. In a specific embodiment, the substrate is cooled to a temperature ranging from about -50 ° C to about 100 ° C. In a more specific embodiment, the substrate is cooled to a range of about _25. The temperature is ramped to within 75 °C, and in an even more specific embodiment, the substrate is cooled to a temperature in the range of from about 0 °C to about 50 °C. As used herein, the term "active cooling," means flowing a cooling fluid adjacent to the substrate. In one embodiment, an electrostatic chuck (ESC) is used to circulate a cooling fluid adjacent the substrate. In another embodiment, a pair of flowing gas is supplied to the chamber and is circulated adjacent to the substrate. According to one or more embodiments, the substrate is actively cooled by flowing a coolant through the substrate support. In a specific embodiment, the coolant is circulated between the substrate and the substrate support member. The substrate may also be cooled, for example, by contacting the surface of the substrate, wherein in a particular embodiment , which comprises a plurality of cooling conduits. In a more specific embodiment, the base 6 201034078 is supplied with a coolant to the cooling conduits. Suitable for use in such embodiments #cooling, containing u, other inert gases And its composition. - or more (d) his embodiment actively cools the substrate by passing a convection gas into the reaction chamber. In a specific embodiment, a helium gas is flowed into the reaction chamber to actively cool the substrate. Material. In a more specific In an embodiment, the convection system flows into the reaction chamber at a flow rate ranging from about 500 sccm to about 3 〇〇〇 sccm. The convection gas used in the embodiment or embodiments comprises oxygen and may also comprise - or multiple Other Inert Gases Some of the features of the present invention are fairly broadly described. It will be appreciated by those skilled in the art that the presently disclosed embodiments can be readily utilized as a basis for adapting or designing other structures or processes falling within the scope of the invention. It is to be understood by those skilled in the art that the equivalent structure does not depart from the spirit and scope of the invention as set forth in the appended claims. Φ [Embodiment] Embodiments of the present invention provide a conformal oxide layer formed by oxidizing a semiconductor substrate. The following specific examples are described with respect to oxide layers formed by low temperature oxidation. As used herein, low temperature oxidation means oxidation at temperatures below about 700 ° C. Conventional plasma oxidation is transmitted The plasma power to the substrate occurs at temperatures above 100 C. At temperatures above !, the oxygen ion flux dominates the oxidation process, thus Only half of the oxygen 7 201034078 flux reaches the vertical sidewalls compared to the oxidized flux of horizontal walls (also referred to as top and bottom surfaces or gates and trenches) that reach a width of 5 nanometers. Accordingly, when the conformality is defined as the growth on one side wall and the growth ratio on a top or bottom surface, conventional plasma oxidation achieves only 50% conformality at thicknesses greater than 25 angstroms. It has been found that the substrate is actively cooled during plasma oxidation to a temperature in the range of about _5 〇 to 1 〇〇C, for example in the specific range of about _25 〇 c to 75, and more specifically in about In the range of 〇 ° C to 50 ° C, the conformality of the film formed by the low temperature oxidation of the yttrium structure can be improved, more specifically, the film conformality of the smaller features having a thickness of less than about 100 nm. Significantly improved. The conformality is defined as the ratio of the thickness of the film formed on the sidewalls of a structure to the horizontal thickness of the film formed on the horizontal surface of a structure comprising the top and bottom surfaces. According to one or more embodiments of the invention, at least about 75% conformality, and more specifically at least about 8%, and in particular embodiments at least about 90%, can be achieved. In one or more embodiments, 较低 by treating in the manner described above, the lower temperature increases the viscosity coefficient of the oxygen species to the sidewalls of a structure. Embodiments of the invention may be practiced in a suitably equipped plasma reactor, such as a depleted nitriding (DPN) reactor available from Applied Materials, Inc. of Santa Clara, California. Other suitable plasma reactors can also be used, including, but not limited to, radial array trough antenna plasma equipment and hollow cathode plasma equipment. Figure 1 shows an exemplary plasma reactor suitable for carrying out an oxide formation process in accordance with an embodiment of the present invention. The reactor delivers low ion energy plasma and high ion energy to the inductively coupled plasma power application 201034078 driven by a continuous wave (CW) power generator. The reactor 11 shown in Figure 1 includes a chamber 10 having a cylindrical side wall 12 and a top plate 14, which may be dome-shaped (as shown), flat, or other geometric shape. A plasma power supply application includes a coil antenna 10 disposed above the top plate 14 and coupled to a power source via a first impedance matching network 18. The power source includes an RF# rate generator 20 and a gate 22 at the output of the generator 2''. The reactor also includes a substrate support 26, which may be an electrostatic chuck or other suitable substrate support for grasping a semiconductor substrate 27, such as a 200 mm or 300 mm semiconductor wafer or the like. . Typically, a heating device is provided, such as a heater 34 below the top surface of the substrate support 26. The heater 34 can be a single or multi-zone heater, such as a dual radial zone heater having radial inner and outer heating elements 3A and 34b, as shown in Figure 1. In addition, the reactor includes a gas injection system 28 and a vacuum pump 30 coupled to the inner space of the chamber φ 1 空间. The gas injection system 28 is supplied from a source of gas, which may include an oxygen cylinder 32, a hydrogen cylinder 62, or an inert gas cylinder 70. Other process gas sources may be included, such as a water vapor source and an inert gas source (not shown). In one or more embodiments, more than one air source flow control valve 66, 64, and 68 can be used to couple the oxygen cylinder 32, the hydrogen cylinder 62, and the inert gas cylinder 7 respectively, and can be used during processing. The frustration is provided to provide a process gas or process gas mixture to the interior of the chamber. Other sources of gas (not shown) that supply additional gases such as nitrogen, gas mixtures, or the like may also be provided. The throttle valve 38 of the true 201034078 air pump 30 can be utilized to control the force within the chamber ι. The duty cycle of the pulsed RF power output at the gate 22 can be controlled by controlling the duty cycle of the pulse generator 36 whose output is coupled to the gate 22. The electropolymer is generated in an ion generating region 39 corresponding to the space under the top plate 14 surrounded by the coil antenna 16g. Since the plasma is generated at a distance from the substrate 27 to the upper half of the cavity, the plasma is referred to as a far-end plasma (for example, the plasma has the advantage of distal slurry formation). , but in the same chamber as the substrate 27, when the operation is performed, the plasma reactor can be used to perform an oxidation process according to an embodiment of the present invention to deposit a high quality oxide layer, which is formed in a There is an incremental oxide layer on the sidewalls of the oxide stack on the substrate. For example, '2A-B shows a stage of fabrication of a semiconductor structure 200 comprising a thin stack 240 formed on a semiconductor substrate 2〇2. In one or more embodiments, the substrate 2〇2 may comprise a plurality of film stacks 24〇, 〇 forming trenches 25〇 between the stacks. The process for fabricating the semiconductor structure 200 described herein can be performed, for example, in the reactor 11 described above with respect to Figure 1. Substrate 202 has a thin film stack 240 deposited thereon. The film will be oxidized 24 堆. The substrate 202 generally corresponds to the substrate 27' of Figure 1 and is typically supported on the substrate support 26 within the chamber 10 of the plasma reactor 11. The substrate 202 can be of various sizes, such as wafers having a diameter of 200 mm or 3 mm, and rectangular or square panels. In some embodiments, the film stack 240 can be formed on the substrate 202 201034078 and then provided to the chamber 1 for the oxidation process. For example, the film stack 240 can be fabricated in one or more process chambers coupled to the -cluster tool, which also has the plasma reactor u coupled thereto. An example of a suitable clustering tool is the gate stack CENTURA® available from Applied Materials, Inc., Santa Clara, California.

The substrate 202 can comprise a material such as crystalline germanium (eg, germanium or stellite), oxygen cut, strain dream, recorded (four), doped or undoped polycrystalline germanium, doped or undoped矽 Wafer, patterned or unpatterned wafers, SOI on insulators, oxygen cuts on carbon, nitriding, dreams, cockroaches, gallium silicate, broken glass, sapphire or the like . It will be appreciated that the film stack 240 is not limited to the particular materials described above. Thus, the film stack 24G can be any type of material stack to be oxidized. For example, 'in some embodiments, such as in a flash memory application, the stack 200 can be a gate stack of a flash memory cell that includes a pass-through oxide layer 204, a floating gate layer 206, a single or a multilayer dielectric layer comprising a polycrystalline dream dielectric layer (IPD) 2! 〇 (one non-limiting example of the IpD - a multilayer ruthenium layer comprising an oxide layer 212, a nitride layer 214, and An oxide layer 216, exemplarily shown in 帛2Α _ _, and a gate layer 220 are controlled. The oxide layers 2〇4, (1), and chuan usually contain dreams and oxygen such as oxidized 7 (Si〇2), oxygenated _(Si〇N), or the like. The vapor layer typically contains chopped nitrogen, such as a gasification dream (SiN) < In some embodiments, a

A multilayer of Si02/A12〇3/Si〇2 is used as the ipD layer 21〇. The floating gate layer 206 and the 丨丨β liver x-diameter gate layer 220 typically contain a conductive material, such as polysilicon, metal, or the like. Film stacks in other applications are expected to be advantageously oxidized according to the teachings provided herein, such as dynamic random access memory (DRAM) metal electrodes/polysilicon gate stacks, charge for non-volatile memory (NVM). Take a flash memory (CTF), or the like. The drAM metal electrode is typically tungsten (w) with an intermediate layer of titanium nitride (TiN) or tungsten nitride (WN) between the layers of tungsten and polysilicon. Charge-extracted flash memory (CTF) for non-volatile memory cartridges (NVM) using Si〇2/sm/Al2〇3 gate stacks with nitrided (TaN) or titanium nitride (TiN) Metal electrodes, which also benefit from sidewall oxidation after gate etching. In certain embodiments, the process gas can comprise water vapor, and in one or more embodiments, the water vapor can be combined with at least one of hydrogen and/or oxygen. Alternatively or in combination, the water vapor may be mixed with at least one inert gas such as atmosphere (He), argon (Ar), helium (Kr), helium (Ne), or the like. In certain embodiments, a process gas (or gas mixture, for example, in the supply of oxygen (〇2) and hydrogen (H2)) may be provided at a total flow rate of between about 1 〇〇 2 〇〇〇 seem' or about 400 seem. In both embodiments, oxygen (〇2) and helium (h2), or about 400 seem', may be provided in the range of the above percentages between about 100 and 2000 seem. In the embodiment providing water vapor. , can pass water vapor with a flow rate of about 5-1000 SCCm, with one or more inert carrier gases such as helium, argon, helium, neon or other suitable gas. These inertia can be supplied as needed. Gas to provide a total flow rate between about 100-2000 seem and to provide a process gas mixture with up to about 50% water 12 201034078 vapor. Inert gas addition can also be combined with H2〆〇2 mixture to avoid ionized oxygen And/or recombination of helium. Excited diatomic molecules generally tend to recombine with themselves in the plasma because the addition of 隋14 milk (such as argon, helium, neon, xenon, or the like) can promote High oxidation rate. A plasma is attached to the chamber 10. From the process gases, an oxide layer 23 is formed on the thin film stack 240. (The plasma is formed in the ion generating region 39 of the chamber 10 shown in Fig. 1, and is inductively coupled by inductive coupling. The RF energy of the coil antenna 16 above the top plate 14 thus advantageously provides low ion energy (e.g., less than about 5 eV for pulsed plasma and less than 15 eV for cw plasma). The low ion energy limits ion bombardment damage and promotes oxidation of the sidewalls of the film stack 24 , while limiting the diffusion of oxygen between its layers, thereby reducing the bird's beak. In some embodiments, about 25 can be provided at an appropriate frequency. Power to 5000 watts to the coil antenna 16 to form a plasma (eg, in the MHz or GHz range 'or about 13.56 μM or greater). This power can be provided in continuous wave or pulse mode. One or more In one embodiment, the power is provided in a pulsed mode with a duty cycle between about 2 and 70%. For example, 'in some embodiments, the plasma can be generated during a continuous "on," period of time. Allowing the plasma's ion energy to Continuous "closed," decay during the interval. The "closed" interval isolates the continuous ''open,' interval, and the open and closed, interval boundaries yield a controllable duty cycle. The ion kinetic energy at the surface of the material is limited to below - pre-13 201034078, the critical energy is in some embodiments, the predetermined critical energy is at or below about 5 eV. For example, in the pulse of the RF power "on, During the time, the plasma energy increases and decreases during the "off" time. During a brief "on, time period" the plasma is approximately corresponding to the space enclosed by the coil antenna 16. It is generated in the ion generating region 39. The ion generating zone 39 is at a significant distance LD above the substrate 27. During the "on" period, the plasma generated in the ion generating region 39 near the top plate 14 drifts toward the substrate 27 at an average speed VD during the "off" time. During each off time, The fastest electrons diffuse to the walls of the chamber, which allows the plasma to cool. The most energetic electrons diffuse to the walls of the chamber at a much faster rate than the plasma ion drift velocity VD. Thus, at this "off" time, the plasma ion energy is significantly reduced before the plasma reaches the substrate 27. During the next "on, time period, more plasma is produced in the ion generating zone 39, and the entire cycle repeats, therefore, • the energy of the plasma ions arriving at the substrate 27 is significantly reduced. At lower chamber pressures In the range, that is, about 1 Torr and below, the plasma energy of the pulsed RF case is greatly reduced compared to the continuous RF case. The "off" time of the pulsed RF power waveform and the ion generating region 39 Both the distance LD with the substrate 27 should be sufficient to allow the plasma generated in the ion generating region 39 to lose a sufficient amount of energy, thus causing little or no ion bombardment damage upon arrival at the substrate 27. Defects. Explicitly the 'this' is off, 'time is between about 2 and 20 kHz, or about 1 kHz, the pulse frequency and between about 5% and 2% of the "on, work week 14 201034078 The term "open" interval may last for about 5 micro and to a time in the range of about 50 microseconds, or about 20 microseconds, and the "closed" interval may last about 5 〇 microseconds to a time in the range of about 95 microseconds, or · 80 microseconds.

In certain embodiments, the ion generating zone to substrate is greater than about 2 centimeters from the LD system or from about 2 centimeters to about 2 centimeters. The ion generating zone-to-substrate distance LD can be about the same as the plasma ion in the pulse RF 瘫 power waveform for a single "off, the distance traveled during the time (vd multiplied by the "off" time) (or Larger. In both the continuous wave and the pulse mode, the plasma advantageously balances the symbiosis of oxygen and hydrogen ions within the chamber and is close enough to the substrate to utilize control of the ion energy. Limiting the loss of activity of the plasma to avoid damage or diffusion damage caused by ion bombardment (eg, bird's beak). The generated plasma can be formed in a low pressure process to reduce the possibility of defects caused by contamination φ. For example, In some embodiments, the chamber 10 can be maintained at a pressure of between about 1.500 mTorr. Further, by using a remote-like plasma source and, optionally, by The plasma power source is pulsed to limit or avoid defects caused by bombardment that can be expected at such low chamber pressure levels. According to one or more embodiments, the oxide layer 23 can be formed to from about 5 angstroms to About 50 angstroms The thickness of the film. The process provides an oxide film growth rate in the range of from about 7 angstroms to about 50 angstroms per minute, or at least about 25 angstroms per minute. The process of the invention disclosed herein provides for a lower thermal budget. 201034078 The above oxide growth rate is increased, thereby further limiting the diffusion effect by reducing the exposure time of the substrate to the process compared to conventional oxidation processes. In some embodiments, the process can have from about 5 seconds. The duration to the range of about 3 sec. The oxide layer 23 can be formed on the film stack 240 to a desired thickness. The substrate 2 〇 2 can then be further processed as needed to complete the fabrication thereon. As described above, it has been found that the substrate is actively cooled during plasma oxidation to a temperature in the range of about _50 ° C to 100 ° C, for example, in a specific range of about _25 ° c to 75 ° C, And more specifically in the range of about 〇 to 50 〇c, the conformality of the film formed by the low temperature oxidation of the ruthenium structure can be improved. The cooling can be accomplished in several ways. According to a first embodiment, the support 26 can be Contains static electricity Disk (ESC) 'cools or contacts the back side of the substrate with a cooling gas, or the side of the substrate in contact with the support 26 to maintain the temperature of the φ substrate during low temperature oxidation. An exemplary embodiment of an ESC 325 is shown. Referring to the reactor 11 of Figure 1, the ESC 325 supports a semiconductor substrate 27 within the chamber 10. The ESC 325 can include a base having a hole 330 therethrough. In the illustrated embodiment, an electrostatic component 333 includes an insulator 335' that encloses an electrode 350. The electrostatic component 333 includes an upper surface 340 for receiving and supporting a substrate. An electrical connector having a voltage supply lead 360 The 355 is electrically coupled to the electrode 350. The voltage supply wire 360 extends along the aperture 330 of the base extending through the ESC 325 and terminates at an electrical contact 3 65 that electrically engages a voltage supply terminal 16 201034078 370. In use, the electrostatic chuck 325 is secured to the support member 375 in the process chamber. It will be appreciated that the ESC 325 can be used in conjunction with the reactor 11 shown in Figure IX. In the embodiment shown in FIG. 3, the process chamber 380 (which corresponds to the chamber ι of FIG. 1) may include a process gas inlet 382 (which corresponds to the gas injection system 28 of FIG. 1), which is coupled to A process gas source 302 (which corresponds to an oxygen cylinder 32, an argon gas cylinder 62 or an inert gas cylinder 70) is supplied to the chamber 380. The process chamber 38 of Figure 3 further includes an exhaust outlet 384 coupled to an exhaust system 301. ❹ In the embodiment of Fig. 3, a substrate 345 is grasped on the ESc 325, and coolant is supplied from the coolant source or cooler 3 to cooling in the upper surface 34 of the insulator 335. The conduit 3〇5 also contains a cooling conduit or ditch. In one or more embodiments, the coolant comprises a conducting gas such as helium, argon, and a broad inert element of Group 8 of the Periodic Table. Substrate 345 gripping the ESC 325 covers and seals the cooling conduits 305 to prevent leakage of the coolant. The cooling • the coolant in the conduit 305 removes heat from the substrate 345 and maintains the substrate 345 at a fixed temperature during processing. In one or more embodiments, the cooling conduits 3〇5 are coupled to the coolant source 3〇〇' by a series of passages that extend through the entire insulator and electrode. The cooling conduits can be spaced apart, sized and dispersed to keep the coolant held therein substantially cool the entire substrate 345I - or in various embodiments, using plasma pulse technology to minimize The ruthenium is heated by the substrate of the plasma power delivered to the substrate. According to these 201034078 embodiments, plasma pulse techniques can be used during plasma oxidation to maintain the substrate at a temperature in the range of about -50 ° C to 100 ° C, for example, at about -25 C to 75 ° C. Within the specific range, and more specifically in the range of about 〇 ° c to 5 ° ° C. Plasma pulses can be implemented in a number of suitable ways. In one embodiment, the plasma can be cycled to maintain the substrate within the temperature range therebetween. In another embodiment, the plasma can be a kHz frequency pulsed plasma ranging from about 2 kHz to about 50 kHz.实施 An embodiment of a plasma pulse technique that uses a switch to cycle the plasma includes adjusting the average plasma electron/m degree and chemistry by pulse or time modulation of the RF plasma power signal. This technique is also known as RJ? The power supply is tuned and controls the electronic temperature independently of the RF plasma power level because during the power off time between pulses, the electron temperature is reduced at a much faster rate than the plasma density ^ RF plasma power modulation includes physical The plasma generation is turned on and off continuously or in a predetermined sequence. In one or more embodiments, the Φ RF plasma power modulation includes turning the power source that produces the ion generating region and the plasma on and off. In accordance with one or more embodiments, the plasma pulse technique includes replacing the ruler between a first frequency and a second frequency. The frequency of the power source. In one or more embodiments, the first and/or second frequencies may also be supplied with different amounts of power. This plasma pulse method is used to maintain or cool the substrate temperature to -50 it and 100. One or more embodiments include placing a substrate in a chamber of the electro-polymerization reactor and introducing a gas containing hydrogen, oxygen or inert gas into the chamber. A frequency is supplied to power 18 201034078 to the reactor to create a first thunderstorm in the chamber. The plasma is not supplied. Then a power is supplied at a second frequency to generate a plasma in the chamber. The class embodiment may also supply a different frequency of work than the first and second frequencies: in one or more embodiments, the = rate = supplied at the first or second frequency may be different and may be related to the frequencies One or both are periodically increased or decreased or remain fixed. The rate of change of the amount of power supplied at the first or second frequency may also be controlled to adjust or lower the temperature of the substrate.

In another embodiment, the temperature of the substrate can be maintained or cooled to between -50 ° C and 100 ° C by gas convection by circulating a cooling or convection gas into the reaction chamber. In one or more embodiments, a cooling gas can flow through the top of the substrate rather than the back side of the substrate. In such embodiments, the chamber can be adjusted to provide another gas inlet that allows the cooling gas to flow into the chamber to cool the substrate. In one or more embodiments, the inlet can be configured to allow the cooling gas to flow adjacent to the surface of the substrate. In one or more embodiments, the cooling gas system is an inert gas supplied to the chamber from a source of cooling gas. In one or more embodiments, the inert gas system is a conducting gas such as helium, argon, and other inert elements within Group 8 of the Periodic Table. Fig. 4 shows the reactor 11 of Fig. 1 and further includes a cooling gas delivery system 29 coupled to the internal space of the chamber 10. The cooling gas delivery system 29 is supplied from a source of cooling gas 82 and circulates a cooling gas into the chamber 10. In one or more embodiments, the source of cooling gas may comprise a helium cylinder. In a specific embodiment, the source of cooling gas may comprise an inert gas mixture gas bottle. Cooling flow control valve 80 is coupled to the cooling source 19 201034078. In the embodiment illustrated in Figure 4, the cooling gas system is supplied to the chamber and flows adjacent the substrate in the direction indicated to cool the substrate temperature. In accordance with one or more embodiments of the present invention, oxide layers, such as gate oxide stacks, may be formed in a stack using a number of methods. The fifth diagram illustrates a trench 250 formed by the space between the two gate stacks 241, 242 and a substrate 203, as shown in Fig. 2a-b. The gate stacks 242 are formed as described above with reference to Figures 2A-B and/or film stack 240. The substrate 203 may also comprise the materials described herein with reference to Figures 2A-B. In FIG. 5, an oxide layer 231 is formed on the substrate 203 over the gate stacks 241, 242 and the trenches 250. The oxide layer is formed in a plasma reactor, for example The reactor 11 described in Fig. 1 utilizes a conventional treatment technique that does not include cooling the substrate. The inventors determined that the substrate was maintained at about -50. The range of 〇 to l〇〇«c Φ improves the conformality of the film or oxide layer formed by the low temperature oxidation method. In one or more embodiments, the conformality can be improved such that the ratio between the thickness of the ceria layer on the sidewalls and the trench is greater than at least 75%. Fig. 5 shows an oxide layer 231 formed using a plasma oxidation process according to the prior art. Figure 5 specifically shows the shallow trench isolation or "STI" structure bottom trench with a gate length of 65 nm and a spacing of 65 nm. The oxide layer 231 of Fig. 5 is deposited in a trench 250 formed between two film stacks, such as the thin film stack 240 shown in Fig. 2B. 20 201034078 The groove 250 is defined by two side walls 251, 252. The semiconductor structure 200 typically comprises a plurality of thin film stacks, such as shown in Figure 2B, having trenches 250 between the thin film stacks. The thickness of the oxide layer 231 formed in the trench 25A shown in Fig. 5 is greater at the bottom of the trench 250 than at the sidewalls 252. The lithium structure of Fig. 5 is formed by growing a channel oxide having a thickness of 75 Å by rapid thermal oxidation and then growing a doped polysilicon layer having a thickness of 12 Å. A high temperature oxide or "HTO" layer having a thickness of 5 angstroms and a nitrogen layer of a final - thick 纟4 (9) angstrom are formed on the polycrystalline layer by a low pressure chemical vapor deposition or "LPCVD" process. The height of the structure formed is approximately 340_380 nm. The gate length and spacing are 65 nm. The thickness of the oxide layer 231 at the sidewalls 25, 252 is between 1.9 nm and 2.1 nm. The thickness of the oxide layer 231 formed on the bottom surface of the trench 25 on the substrate 2〇3 is about 32 nm. The conformality of the oxide layer 231, that is, the ratio of the thickness of the ruthenium oxide layer 231 at the sidewalls 251, 252 to the thickness on the substrate 203 is in the range of from about 0.59 to 0.66. Figure 6 illustrates an oxide layer 232 formed on the same type of substrate and structure as used in Figure 5, however, the method of forming the oxide layer 232 includes cooling or maintaining the temperature of the substrate 203 using an ESC. , so described. The substrate 203 is placed in a chamber, an Esc, as described elsewhere in the specification, and during the plasma oxidation process, the back side of the substrate 203 or the side of the substrate that is in contact with the ESC. It is cooled by helium. In the embodiment illustrated in Figure 6A, the oxide layer 232 21 201034078 utilizes a power supply of about 2000 watts and contains 80 by a room temperature plasma oxidation process. /. A process gas of hydrogen gas and a total flow rate of 2 〇〇 s Ccm is formed. The helium cooling gas system used in the ESC was set at 4 t and the substrate was cooled to from about 30 eC to about 50. (: temperature in the range. The thickness of the formed oxide layer 232 at the sidewalls 251, 252 is between 2.5 nm and 2.7 nm. "The oxide layer 232 is at the bottom surface of the trench 250. The thickness is 27. 7 nm. The conformality of the oxide layer 232 is between 0.93 and 1. ® See Figure 6B 'Using the plasma pulse method described herein in the figure with Figure 5 An oxide layer 233' is formed on the same type of substrate and structure to maintain or cool the substrate temperature. As described elsewhere, the RF power supply signal is supplied by circulating power to the reactor. Pulse ° utilizes a giant pulse process to switch the plasma power according to the following formula. • Turn on 4 times for 25 seconds and turn off 4 times for 120 seconds. Use rt decoupled plasma oxidation or “Dp〇” using a 2000 watt power source. The chamber φ forms the oxide layer. The process gas used to form the oxide layer contains 80% of gas and flows into the chamber at a flow rate of about 2 〇〇 sccni. The substrate temperature is cooled. Oxide formed to a temperature ranging from about 2 ° C and about -30 ° C The thickness of layer 233 at the sidewalls 251, 252 is 2.8. The thickness of the oxide layer 233 at the bottom surface of the trench 25 is 3.1 nm, resulting in a conformality of 〇.9 。. The results clearly show that it was found that maintaining the substrate temperature at or cooling to a temperature in the range of about -50 ° C and l 〇〇eC during plasma oxidation produces a conformal oxidation 22 201034078 layer. References to "an embodiment," "some embodiments or embodiments" or "an embodiment" or "an embodiment," Included in the present invention is at least a towel. Thus, throughout the text of this (4), for example, "in" or "in the embodiment", "in some embodiments,", "in an embodiment," or "In an embodiment, the appearance of a sentence does not necessarily refer to the same embodiment of the invention. Furthermore, the feature material or feature may be combined in any suitable manner in one or more embodiments. The order in which the above methods are described should not be considered as limiting, and such The above description may be used in a manner that is not intended to be limiting or to be added or added, and the description is intended to be illustrative, and not restrictive. After that, many other embodiments will be apparent to those skilled in the art: Therefore, the scope of the present invention should be determined by reference to the scope of the appended claims, and the scope of the claims is to be construed as the scope of the equivalents. That is, a more descriptive description of the present invention, briefly outlined above, may be obtained by reference to the examples, some of which are illustrated in the drawings, but it should be noted that the appendices only show the general implementation of the invention. The scope of the invention is not to be construed as limiting the scope of the invention. 23 201034078 Figure 1 shows a plasma reactor in accordance with an embodiment of the present invention; 2A-B illustrates a stage of fabrication of a semiconductor structure in accordance with one or more embodiments of the present invention; An electrostatic chuck according to an embodiment of the present invention; FIG. 4 shows a plasma reactor chamber including a pair of flow gas sources; and FIG. 5 shows an oxide layer formed by a prior art plasma oxidation process; 6A-6B illustrate an oxide layer formed using a plasma oxidation process in accordance with one or more embodiments of the present invention. [Main component symbol description] 10, 380 Chamber 11 Reactor 12 Sidewall 14 Top plate 16 Coil antenna 18 First impedance matching network 20 RF power generator 22 Gate 26 Substrate support 27, 202, 345 Semiconductor substrate 28 Gas Injection system 29 Cooling gas delivery system 24 201034078 30 Vacuum pump 32 Oxygen cylinder 34 Heater 34a, 34b Heating element 36 Pulse generator 38 Throttle valve 39 Ion generation zone 62 Hydrogen cylinder 64, 66, 68 Flow control valve 70 Inert gas Bottle 80 Cooling Flow Control Valve 82 Cooling Gas Source 200 Semiconductor Structure 204 Tunneling Oxide Layer 206 Floating Gate Layer 210 Polycrystalline Dielectric Dielectric Layer Oxide Layer 212, 216, 230, 231, 232, 233 214 Nitride Layer 220 Control gate layer 240 film stack 241, 242 gate stack 250 trenches 251, 252 sidewall 300 coolant source 25 201034078

301 302 305 325 330 333 335 340 350 355 360 365 370 375 382 Exhaust system process air supply cooling duct electrostatic chuck hole electrostatic component insulator upper surface electrode electrical connector voltage supply wire electrical contact voltage supply terminal support process gas inlet row Gas outlet 384

Claims (1)

201034078 VII. Patent Application Range: 1. A method for treating an oxide layer on a semiconductor substrate, comprising at least: placing a substrate to be oxidized in a plasma reaction chamber having a source-ion generating region On the support member; introducing a process gas into the chamber; and generating a plasma in the ion generating region of the plasma reaction chamber to form an oxide layer on the substrate, the oxide layer having a horizontal surface The thickness and a thickness of the sidewall, while actively cooling the substrate to a temperature in the range of about -5 (TC to 1 〇〇 °c. 2. The method of claim </ RTI> wherein the substrate temperature is The oxide layer is formed by active cooling to a temperature in the range of about _25 〇c to 75 ° C. The method of claim 1, wherein the substrate temperature is in the oxide The layer is formed by active cooling to a temperature in the range of about 〇 & & 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 4. 主动 主动 主动 主动 主动 主动Passing a coolant through the substrate The method of claim 4, wherein the substrate support comprises a surface comprising a plurality of cooling conduits and actively cooling the substrate temperature comprising comprising the substrate (four) The surface of the material support is connected to the above-mentioned substrate coolant to the cooling. 6. The method of claim 5 further comprises a series of channels for supplying a conduit. 7. The method of claim 4, wherein the actively cooling the substrate temperature comprises flowing-convection gas into the reaction chamber. 8. The method of claim 7, wherein the convective gas comprises helium. • The method of claim 7, wherein the convective gas comprises a flow rate in the range of from about 500 SCCm to about 3000 sccm. A method for forming an oxide layer on a semiconductor substrate, comprising: placing a substrate to be oxidized on a substrate support in a chamber of a plasma reactor, the chamber Having an ion generating region; introducing a process gas into the chamber; and generating a plasma in the ion generating region of the chamber to form an oxide layer on the substrate 28 201034078 while actively cooling the The substrate is at a temperature below about 100 C. 11. The method of claim 10, wherein the plasma comprises an oxygen species, and actively cooling the substrate increases a viscosity coefficient of the oxygen species. 12. The method of claim 1, wherein the main cooling of the substrate comprises flowing a pair of flowing gases to the reactor. 13. The method of claim 1 wherein said actively cooling said substrate comprises circulating a coolant between said substrate and said substrate support member. 14. If the patent application scope 13 φ agent contains helium. The method of the above item, wherein the cold method is as described in claim 14, wherein the agent further comprises a second inert gas. 29