Method of linearized film oxidation growth

Abstract

A method for forming an oxide layer on a semiconductor substrate is provided. The method includes forming a first oxide-containing portion of the oxide layer on the substrate by exposing the semiconductor substrate to a first gas mixture having a first oxygen percentage at a first temperature, and forming the oxide layer at a first growth rate. A second oxide-containing portion is formed on the substrate by exposing the substrate to a second gas mixture having a second oxygen percentage at a second temperature, and forming the oxide layer at a third growth rate. The first growth rate is slower than each subsequent growth rate, and each growth rate after the second growth rate differs from the previous one by no more than 50%.

Description

Technical Field

[0001] The embodiments of this case are generally related to the manufacture of semiconductor devices, and more specifically, to the oxidation of substrates (such as semiconductor substrates). Prior Technology

[0002] The integrated circuit (IC) market is constantly demanding larger memory capacities, faster switching speeds, and greater feature densities. To enable the fabrication of next-generation devices and structures, three-dimensional (3D) stacking of semiconductor memory chips is commonly used to improve transistor performance. By arranging transistors in three dimensions rather than the traditional two-dimensional arrangement, multiple transistors can be placed very close to each other in an integrated circuit. 3D stacking of semiconductor chips reduces wiring length, maintains low wiring delay, and increases on-chip device density. When forming flash memory structures, thin-film stacks are placed on a substrate and an etching process is performed to etch trenches into the thin-film stack. Due to the requirement for a high number of repeating alternating layers in the thin-film stack to achieve higher device performance, thin-film stacks with channel structures typically have a high aspect ratio. Furthermore, manufacturers are continuously increasing the stack height, thereby increasing the channel length. Oxide layers are formed by exposing the stack to an oxidation process. Oxidation processes are typically performed thermally and / or using plasma.

[0003] These features are processed using an oxidation process to produce oxide films along channels with high aspect ratios and / or on long, narrow features. Due to the reaction kinetics of the interaction between the process gas and the silicon surface, current oxidation processes exhibit non-conformal film growth behavior. Non-conformal oxide layers can lead to poor device performance or failure. Furthermore, the oxidation time can be increased to improve the conformality of the oxide film; however, the increased oxidation time affects the overall yield of the device.

[0004] Therefore, an improved method for forming conformal oxide films is needed. Summary of the Invention

[0005] The embodiments of this invention generally relate to a method of forming an oxide layer on a semiconductor substrate. The oxide layer includes a first oxide-containing portion formed at a first growth rate by exposing the substrate to a first gas mixture having a first oxygen percentage at a first temperature. A second oxide-containing portion is formed on the substrate at a second growth rate by exposing the substrate to a second gas mixture having a second oxygen percentage at a second temperature. A third oxide-containing portion is formed on the substrate at a third growth rate by exposing the substrate to a third gas mixture having a third oxygen percentage at a third temperature. The first growth rate is slower than each subsequent growth rate, and each growth rate after the second growth rate differs from each other by less than 50%.

[0006] In another embodiment, a method for forming an oxide layer on a semiconductor substrate is provided. The method includes introducing a gas mixture into a volume of a processing chamber, and increasing the volume of the processing chamber under two or more property conditions on a substrate support, starting from a first property condition among a plurality of conditions. Increasing the property includes incrementing from the first property condition to each subsequent property condition, and then incrementing to a final property condition. Each transition to a subsequent property condition corresponds to a respective ramp time. Each property condition between each increment is held for a respective holding time. Each holding time is greater than each ramp time. The property is temperature, the oxygen percentage of the gas mixture, or a combination of the above.

[0007] In another embodiment, a method for forming an oxide layer on a substrate is provided. The method includes determining a total growth factor for the portion used to form the oxide layer. The total growth factor is determined based on a predetermined total thickness of the oxide layer, a total process time for forming the oxide layer, and a predetermined conformality tolerance. The predetermined conformality tolerance is determined based on deviations in the oxide layer thickness at two or more locations on the substrate surface. A plurality of sub-operations and corresponding growth factors are determined. The corresponding growth factors together form a linear interpolation between zero and the total growth factor. The plurality of sub-operations includes a ramp time between sub-operations, a holding time, an oxygen percentage in the gas mixture used to form each portion of the oxide layer, and a temperature in each sub-operation. Each subsequent sub-operation in the plurality of sub-operations includes increasing the temperature, oxygen percentage, or a combination of the above. Each ramp time is substantially equal to each other, and each ramp time is less than each holding time. Simple Explanation of the Diagram

[0008] A more specific description of the above-briefly summarized present invention can be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings, in a manner that enables a detailed understanding of the aforementioned features of the present invention. However, it should be noted that the drawings illustrate exemplary embodiments only and should not be construed as limiting the scope of the present invention, and that other equally effective embodiments are permissible.

[0009] Figure 1 illustrates a schematic diagram of a heat treatment chamber with a remote plasma source according to an embodiment.

[0010] Figures 2A and 2B illustrate schematic cross-sectional views of channel features before and after an oxidation process according to an embodiment.

[0011] Figure 2 illustrates a flowchart of a method for forming an oxide layer on a silicon substrate according to an embodiment.

[0012] Figure 4 is an illustrative graphical representation of a comparative oxidation process and the growth behavior of the oxidation thickness over time according to an embodiment.

[0013] Figure 5 illustrates an illustrative graphical representation of a comparative oxidation process and the kinetic rate of oxidation process growth with increasing oxidation thickness according to an embodiment.

[0014] Figure 6 illustrates an illustrative graphical representation of multiple temperature ramp conditions varying over time according to an embodiment.

[0015] To facilitate understanding, the same element symbols have been used to denote common elements in the drawings, where possible. It is anticipated that elements and features of one embodiment may be beneficially incorporated into other embodiments without further description. Implementation

[0016] The embodiments described herein generally relate to a method for forming an oxide layer in multiple sub-operations, each sub-operation including property conditions such as temperature and / or gas composition conditions. The conditions and time in each sub-operation are controlled to produce a generally linear oxide film growth rate. A plurality of oxide-containing portions of the oxide film are formed on a semiconductor substrate using a plurality of sub-operations. Each sub-operation for each oxide-containing portion modifies at least one property, such as increasing the temperature of the gas mixture used to form the portions of the oxide film or increasing the oxygen percentage. The temperature and oxygen percentage are modified simultaneously, or one is variable while the other is fixed. Each sub-operation includes a corresponding growth rate of the oxide film. The number of sub-operations and the sub-operation property conditions are determined to control the oxidation growth rate to produce a conformal oxide film on the substrate.

[0017] The method of this invention is carried out in a suitably equipped plasma reactor and / or heat treatment chamber, such as a rapid thermal process (RTP) chamber or a small-batch rapid heating furnace. Figure 1 illustrates a treatment chamber 100 according to an embodiment, such as a rapid thermal process chamber having a remote plasma source 120. The rapid thermal process chamber employs heating from radiant heat, such as from a hot incandescent lamp, or from radiant energy, such as heating from a laser annealing system.

[0018] Processing chamber 100 includes a chamber body 101 defining a processing volume 110 in which a substrate 102 can be heat-treated. The substrate 102 is positioned on a substrate support 112, for example on a pin or on a low-mass edge ring for rapid heating. An energy source 103 is configured to direct radiant energy 105 to the processing volume 110. A sensor 108 is positioned to measure properties of elements within the internal chamber body 101. The sensor 108 is configured to measure the temperature of the substrate 102 by receiving and measuring the radiant energy from the substrate 102. The sensor 108 can be connected to a system controller 109, which can adjust the energy source 103 based on measurements from the sensor 108.

[0019] A remote plasma source (RPS) 120 is connected to the processing chamber 100. The RPS 120 used herein is any suitable RPS capable of generating a remote plasma having at least oxygen. The RPS 120 is fluidly coupled to the processing chamber 100 via a first conduit 122. An oxygen source 126 is also fluidly coupled to the RPS 120, such as a microwave, capacitive, or inductively coupled remote plasma source. Further embodiments may include an inert gas source 128 coupled to the RPS 120 to generate an oxygen / inert gas plasma that can be delivered to a processing volume 110 of the processing chamber 100.

[0020] Hydrogen source 124 is coupled to processing chamber 100. Hydrogen source 124 delivers hydrogen to processing volume 110 via second conduit 132, where the hydrogen is activated by oxygen plasma delivered from RPS 120.

[0021] Temperature control promotes the formation of high-quality silicon oxide. Therefore, the processing chamber 100 and / or elements such as the substrate support 112 used in the embodiments described herein can be controlled at a temperature between approximately 500°C and approximately 1100°C, while rapidly heating and cooling the substrate 102 in the processing chamber 100.

[0022] Figures 2A and 2B illustrate schematic cross-sectional views of a channel structure before and after an oxidation process according to an embodiment. Figure 2A illustrates a partially fabricated semiconductor structure (e.g., substrate 102). The structure includes a base substrate 200 having a first layer 210 on its surface. The first layer 210 includes a channel structure 212 having a top 214, a bottom 216, and sidewalls 218. The sidewalls 218 include three equally divided portions, including a top 206, a middle 204, and a bottom 202. The first layer 210 of the substrate 102 is composed of a semiconductor composition, such as silicon or a silicon-containing composition, such as silicon nitride or silicon carbide. The first layer 210 may be a single layer or a stack of layers. One or more stacks of layers may be deposited using atomic layer deposition or plasma-enhanced chemical vapor deposition. The channel structure 212 includes two sidewalls 218, but it should be understood that other structures 212 having one, two, three, four, or more sidewalls or portions of sidewalls may be used. For example, through-holes can benefit from the various configurations of this case. The channel structure 212 has an aspect ratio greater than about 10:1, such as about 50:1 to about 100:1.

[0023] Figure 2B shows the channel structure 212 after the oxidation process in this invention. An oxide layer 220 is produced on the silicon layer 210 via oxidation of the surface of the silicon layer 210. The oxidation process involves introducing oxygen and hydrogen into a processing chamber. Conventionally, hydrogen is introduced at a relatively low concentration and a high process temperature is used in a single step. The silicon surface is oxidized in oxygen, such as atomic oxygen, including species generated by oxygen plasma, or by gaseous chemical combustion using hydrogen and oxygen. Conditions for oxidizing silicon can be achieved using hydrogen (H₂) and oxygen (O₂) (including plasma-activated oxygen). A single high-temperature oxidation process (e.g., a conventional oxidation process) produces a film with less than 95% conformability on the channel. As used herein, conformability is defined as the ratio of the oxide layer thickness formed on the lower portion 202 of the channel structure 212 to the oxide layer thickness on the top portion 206 of the channel structure 212. In contrast, the multi-temperature oxidation process described in this case provides 95% to 100% conformality. Thickness measurements were performed using any known method for measuring film thickness, such as by using transmission electron microscopy (TEM).

[0024] Figure 3 illustrates a method 300 for forming an oxide layer on a silicon substrate according to an embodiment. The oxide layer is formed by exposing a silicon-containing surface (e.g., polycrystalline silicon or silicon nitride film) on the substrate to oxygen plasma in the presence of heat. Each operation is described herein with reference to the remaining figures (Figures 4 through 6). In operation 302, a first oxide-containing portion is formed in a first sub-operation. In operation 304, a second oxide-containing portion is formed in a second sub-operation; in operation 306, a third oxide-containing portion is formed in a third sub-operation; and operation 308 represents a plurality of sub-operations for the nth sub-operation.

[0025] The first oxide-containing portion of the oxide layer is formed by introducing a gas mixture into a chamber at a flow rate of about 1 slm to about 15 slm, such as about 10 slm. The gas mixture is about 5% to about 90% hydrogen, such as about 15% to about 50% hydrogen, about 0% to about 50% argon, and about 5% to about 95% oxygen, such as about 10% to about 50%, such as about 20% to about 30%, or about 60% to about 90%, such as about 70% to about 80% oxygen. As used herein, percentages (%) relative to the gas are atomic. The total chamber pressure is maintained at about 0.5 Torr to about 3 Torr, such as about 1 Torr to about 2 Torr. This invention provides a method for incrementally adjusting the oxygen percentage of a gas mixture using fixed hydrogen and argon flow rates, and adjusting the oxygen flow rate or adjusting one or more of the hydrogen and argon flow rates while maintaining the oxygen flow rate. In some embodiments, the temperature of the substrate is constant when adjusting the oxygen percentage in the gas mixture.

[0026] The first temperature of the substrate is approximately 550°C to approximately 620°C, for example, approximately 610°C. The multi-operation oxidation process described in this case follows a kinetic behavior similar to the graphical representation shown as 404 in Figure 4. The kinetic behavior of the reaction in operation 302 of the multi-operation oxidation process is represented in the first sub-operation 410, defined between the first time 409 and the second time 411. In contrast, conventional oxidation processes follow a kinetic behavior similar to the graphical representation shown as 402 in Figure 4. Although the graphical representation 402 appears to be a semi-parabolic shape, the kinetic behavior of a single operation can have other non-linear shapes, such as those represented by logarithmic or exponential functions. The horizontal axis (t) is a measure of time, such as in seconds (s), and the vertical axis (Y) is a measure of oxide layer thickness, such as in angstroms (Å), so that the curve 402 represents the increase of film thickness over time, and each data point has units of Å / The general dynamic equation is determined by the following equation: Equation 1A:

[0027] Y is the total oxidative growth of n operations (e.g., the total cumulative growth of all operations m); t is time; A is the experimentally derived growth coefficient, such as between about 1 Å*sec -1 / 2 and about 12 Å*sec -1 / 2, determining each operation m; z is any number greater than 0 and less than 1 (e.g., a fraction), such as about 1 / 2, and h is the time offset for each passed operation m.

[0028] The general equation of motion for a horizontal parabola with z = ½ is determined by the following: Equation 1B:

[0029] As used herein, the coefficient increment is the difference between each pair of sequential suboperations. Slower growth coefficient conditions are used for thinner oxide growth thicknesses (Y), and faster growth coefficient conditions are used for thicker oxide growth thicknesses (Y). Unbound by theory, it is believed that oxidant diffusion to the growth interface (such as an interface composed of silicon) initially exhibits rapid kinetics as the oxidant diffuses rapidly. As the oxide film grows, the reactivity of the interface generally decreases. To form a relatively thin surface, slower growth conditions are used to provide conformal films within a reasonable process time. Slowing down the growth or reactivity of film formation allows the oxidant to penetrate further into features with high aspect ratios. Conventional processes typically show evidence that reactants are consumed at the top of the channel and significantly reduced deeper into the feature.

[0030] The kinetic rate d(Y) / dt is defined by the derivative of the thickness growth over time, and is illustrated in Figure 5, 502 (for a single-operation oxidation process) and 504 (for multiple sub-operation oxidation processes). For each sub-operation, the kinetic rate is determined according to the general kinetic rate equation for Y by the following: Equation 2A: For each sub-operation, the general dynamic rate equation for z = ½ is determined by the following formula: Equation 2B: The kinetic rate coefficient is equal to Multi-operation oxidation processes with two or more operations can reduce the overall kinetic rate variation, resulting in an approximately linear rate as shown by line 440 in Figure 4. This is also illustrated in Figure 5, where the kinetic rate functions for each sub-operation (e.g., 410, 412, 414, 416) are compared for single-operation function 502 and multi-operation function 504. As can be seen, the dY / dt value of 502 at the start of the process (e.g., 410) is much larger than that at the end of the process (e.g., 416). The kinetic rate at the first sub-operation is approximately four times or more the kinetic rate of the last sub-operation 416. Conversely, for multi-sub-operation function 504, each sub-operation is substantially the same, and its kinetic rate ranges less than about four times, for example, about 1.2 to about 3 times, or about 1.2 to about 2 times, relative to each other.

[0031] As shown in Figures 4 and 5, the first oxide-containing portion forms in a generally slower and controlled manner under first property conditions (such as the temperature shown at 602 in Figure 6) compared to a single-temperature comparison process using a single, higher temperature. Although Figure 6 depicts "T" on the vertical axis of "temperature," other properties are also expected and can be controlled to provide similar behavior. In some embodiments, this property is the composition of the gas mixture, such as the percentage of oxygen (atoms) in the gas mixture. Operation 302 is maintained for a first holding period of approximately 10 seconds to approximately 30 seconds. The conditions of operation 302 are maintained for a period of approximately 15% to approximately 50% of the entire oxidation process from start to finish.

[0032] Operation 304 includes a second oxide-containing portion in which an oxide layer is formed in a second sub-operation 412, which includes a second property condition 604, such as a temperature condition. The transition from operation 302 to operation 304 is represented by a first transition 411 in Figures 4 and 5 and a first property ramp 603 shown in Figure 6. Each of the property ramps is a temperature ramp (e.g., 603, 605, 607) that increases the temperature by about 50°C to about 90°C, such as about 60°C to about 70°C, over a time period of about 1 second to about 20 seconds, such as about 5 seconds to about 10 seconds. In some embodiments that may be combined with other embodiments described herein, each ramp rate (e.g., heating rate) is about 50°C to about 90°C per second, such as about 70°C to about 80°C per second.

[0033] While adjusting the temperature, a second oxide-containing portion is formed using the same gas mixture composition and gas flow rate as in the first sub-operation 410. In addition to adjusting the temperature, one or more of the gas mixture composition and gas flow rate are adjusted to maintain the predetermined kinetic rate shown by 504 in Figure 5. Alternatively, the second oxide-containing portion is formed using the same temperature as in the first sub-operation 410, while adjusting the gas mixture, for example, adjusting the oxygen percentage of the gas mixture. Adjusting the oxygen percentage of the gas mixture includes changing the flow rate of oxygen relative to other gases, or changing the flow rate of one or more other gases relative to oxygen, or a combination of the above.

[0034] In some embodiments that may be combined with other embodiments described herein, the property ramps (e.g., 603, 605, 607) are oxygen percentage ramps, and the vertical axis represents the oxygen percentage in the gas mixture. Each oxygen percentage ramp increases the oxygen percentage by about 5% to about 50%, for example, about 10% to about 20%, over a time period of about 1 second to about 20 seconds, such as about 5 seconds to about 10 seconds. In some embodiments that may be combined with other embodiments described herein, each ramp rate (e.g., oxidant rate) is about 0.5% to about 10% per second, such as about 1% to about 5% per second.

[0035] While specific ramp ranges are provided for illustrative purposes, other ramp ranges can be expected depending on factors related to the selection of the target kinetic rate, such as the desired product properties and quality, the aspect ratio of the channels within the process substrate, the width-to-height ratio of the elongated features to be processed, and yield and energy considerations. The rates of the property ramps (e.g., 603, 605, 607) may be equal or unequal.

[0036] Each target kinetic rate for each sub-operation is also determined based on the number of sub-operations selected for the oxidation process. Specifically, each target kinetic rate is obtained by adjusting operating parameters to maintain substantially equal kinetic rate profiles in each sub-operation. Although Figures 4 through 6 illustrate four sub-operations, each with its own operating conditions, other numbers of sub-operations can be anticipated, such as approximately two to approximately seven. Each sub-operation has a predetermined growth factor determined by dividing the total growth factor by (e.g., the number of sub-operations shown in 502) the number of sub-operations, and then incrementing the growth factor increment for each sub-operation. For illustrative purposes, the overall growth coefficient for 12 and 4 sub-operations is incremented by 3 (e.g., 12 divided by 4), and the individual growth coefficients for each sub-operation (e.g., first, second, third, and fourth) are 3, 6, 9, and 12, respectively. More generally, the growth coefficient increment can be described as... or , where n is the total number of suboperations of each suboperation m. In the example above, , n=4, m is each sub-operation from 1 to n.

[0037] The overall growth factor is determined by establishing an estimated growth function for the oxidation process. The estimated growth function is the kinetic behavior of the oxide substrate (e.g., a silicon substrate) and determines the relationship between oxide layer growth and time under a single operation (e.g., a single temperature condition). Theoretically, a long-duration function with low surface reactivity will produce sufficient conformability across the entire substrate surface when oxygen permeates the feature and / or the entire surface length. However, long process times are impractical because they reduce yield. Furthermore, functions with high reactivity over short periods produce relatively high device yields but are limited in conformability because reactants will be further lost along the feature. Single-operation oxidation processes use a single high-temperature and / or high-oxygen exposure, which is highly reactive at the start and rapidly decreases in reactivity, exhibiting behaviors such as horizontal parabolic curves. Compared to conventional processes, oxidation processes performed under several different sub-operations can mitigate the reactivity of the first operation at high hydrogen concentrations and lower temperatures, and maintain generally linear behavior by increasing the temperature and / or adjusting the reactant chemistry, such as decreasing the hydrogen flow rate or increasing the oxygen flow rate. The estimated growth function is a function of the estimated total growth coefficient and time-dependent variables used to form the oxide layer. The coefficient increment between sub-operations is determined by dividing the total growth coefficient by the number of sub-operations used to form the oxide layer. The first growth coefficient corresponds to the formation of the first oxide-containing portion and is equal to the coefficient increment. Each oxide-containing portion corresponds to its own growth coefficient, wherein each subsequent oxide-containing portion after the first oxide portion has a corresponding growth coefficient that increases the coefficient increment. The growth coefficient is a measure of the reactivity of oxygen with the substrate.

[0038] Other methods for determining each kinetic behavior are also contemplated to make a multi-operation process (e.g., 404) generally linear compared to a comparative single-operation process (e.g., 402). The kinetic behavior is controlled by increasing the temperature in each operation and / or adjusting the holding time of each operation. In some embodiments that can be combined with other embodiments described herein, the first holding time in the first sub-operation 410 is about 2% to about 20% less than the second holding time in the second sub-operation 412, for example, about 5% to about 13% less. Alternatively, the first holding time is about 2% to about 12% greater than the second holding time, such as about 5% to about 10%. In some embodiments, for each operation, the second holding time is substantially equal to within about 10% or about 5% of the respective holding times. Each holding time is determined based on the number of sub-operations (e.g., four sub-operations for illustrative purposes), thereby determining the ramp time between each holding time (e.g., for each of the three transitions between operations). Each ramp time is approximately 1 to approximately 10 seconds, such as approximately 3 to approximately 7 seconds, such as approximately 5 seconds. The total oxidation time is determined to be such as approximately 40 to approximately 120 seconds, such as approximately 60 to approximately 80 seconds. The total oxidation time depends at least on the predetermined oxide film thickness. The total oxidation time decreases with ramp times. Ultimately, each holding time is determined based on an estimated single operating function to produce a generally linear kinetic reaction curve, as represented by 404 in Figure 4. The estimated function can be refined experimentally. The behavior of each sub-operation (see, for example, the second sub-operation 412 shown in Figure 5) depends on the thickness of the oxide film grown from the beginning of sub-operation 412 (e.g., transition 411 in Figure 5) to its end (e.g., transition 413 in Figure 5). Specifically, the kinetic rate With equation 2B The thickness of the oxide film during growth is indicated. There is an inverse relationship between them, which depends on the kinetic rate coefficient. It is believed that the kinetic rate can be controlled and reduced in each sub-operation by increasing the thickness of the oxide film by a predetermined amount. Each sub-operation includes an average kinetic rate, and the average kinetic rate of each sub-operation is substantially equal.

[0039] Operation 306 includes forming a third oxide-containing portion of the oxide layer in a third sub-operation 414. The kinetic rate (e.g., the average kinetic rate of forming the third oxide-containing portion) is within about 50% of the kinetic rate of forming the second oxide-containing portion formed in the second sub-operation, such as within about 15% to 30%, or 20% to 40%. Furthermore, each subsequent operation has a kinetic rate within about 50%, such as within about 15% to 30%, or 20% to 40% of the previous sub-operation. The transition from operation 304 to operation 306 is represented by the second transition in Figures 4 and 5 and the second temperature ramp 605 shown in Figure 6. The second temperature ramp 605 includes increasing the temperature from the second temperature condition 604 to the third temperature condition 606. Operation 308 is generally described as forming the nth oxide-containing portion in the nth sub-operation, such as the fourth sub-operation 416 and the third transition 415 in Figure 4. The third transition 415 includes a third property ramp 607, which increases the property condition from the third property condition 606 to the fourth property condition 608, which further ascends incrementally to the nth sub-operation (e.g., the last sub-operation). In some embodiments that may be combined with other embodiments described herein, the last sub-operation includes heating the substrate to a final temperature of approximately 700°C to approximately 1000°C, such as approximately 750°C to approximately 850°C, such as approximately 800°C. The multiple sub-operation oxidation method includes ramping the substrate temperature from a first temperature condition (e.g., approximately 550°C to approximately 620°C) to a final temperature condition (e.g., approximately 700°C to approximately 1000°C). In some embodiments that may be combined with other embodiments described herein, the last sub-operation includes increasing the oxygen percentage to a final oxygen percentage of approximately 70% to approximately 95% in the gas mixture. The multi-sub-operation oxidation method involves gradually increasing the oxygen percentage of the gas mixture from a first oxygen percentage condition (e.g., about 5% to about 30%) to a final oxygen percentage condition (e.g., about 70% to about 95%). This can be done by increasing the oxygen percentage while maintaining a fixed temperature of about 700°C to about 800°C, or by increasing the oxygen percentage while modifying the temperature of each sub-operation. The property increments between the sub-operations are determined to produce generally linear kinetic behavior as shown in 404 of Figure 4. It is anticipated that any number of sub-operations can be used, such as three or more. The more sub-operations used, the more linear the oxidation kinetics will be.

[0040] In summary, the embodiments described herein are generally related to methods for forming oxide layers in multiple sub-operations, such as temperature and / or oxygen percentage conditions. Conditions and time under each condition are controlled to produce a generally linear growth rate of the oxide film formed by oxidation. The method includes forming a first oxide-containing portion of the oxide layer over a semiconductor substrate at a first growth rate and first property conditions. The method further includes forming a second oxide-containing portion on the substrate at a second growth rate and second property conditions, and forming a third oxide-containing portion on the substrate at a third growth rate. Each temperature is gradually increased to control the oxidation growth rate to produce a conformal oxide film on the substrate.

[0041] The embodiments described herein generally relate to a method for forming a plurality of oxide-containing portions on a semiconductor substrate using a plurality of sub-operations. Each sub-operation of each oxide-containing portion modifies at least one property, such as increasing the temperature of the gas mixture used to form the portions of the oxide film or increasing the oxygen percentage. The temperature and oxygen percentage are modified simultaneously, or one of them is variable while the other is fixed. Each sub-operation includes a corresponding growth rate of the oxide film. The number of sub-operations and sub-operation property conditions is determined to control the oxidation growth rate to produce a generally linear oxide film growth rate, thereby forming a conformal oxide film on the substrate.

[0042] Although the foregoing is directed to embodiments of this case, other and further embodiments of this case may be designed without departing from the basic scope of this case, and the scope of this case is determined by the subsequent claims.

[0043] As used herein, the term "about" means a difference of + / - 10% from the nominal value. It should be understood that this variation may include any of the values ​​provided herein.

[0044] 100: Processing Chamber 101: Main body of the chamber 102:Substrate 103: Energy Source 105: Radiant Energy 108: Sensor 109: System Controller 110: Processing volume 112: Substrate support 120: Remote plasma source 122: First Pipeline 124: Hydrogen source 126: Oxygen source 128: Inert gas source 132: Second Pipeline 200: Base substrate 202:lower part 204: Central 206: Top 210: First Floor 212: Channel Structure 214: Top 216: Bottom 218: Sidewall 220: Oxide layer 300: Method 302: Operation 304: Operation 306: Operation 308: Operation 402: Single-operation process 404: Multi-operation process 409: First Time 410: Sub-operation 411: Second Time 412: Sub-operation 413: Transformation 414: Sub-operation 415: Transformation 416: Sub-operation 440: Linear speed 502: Single-operation function 504: Multiple Operation Functions 602: Temperature 603: Property Slope / Temperature Slope 604: Second temperature condition 605: Property Slope / Temperature Slope 606: Third temperature condition 607: Property Slope / Temperature Slope 608: Fourth attribute condition

[0045] Domestic storage information (please note in order of storage institution, date, and number) none Overseas storage information (please note in the order of storage country, institution, date, and number) none

Claims

1. A method of forming an oxide layer, comprising the steps of: exposing a semiconductor substrate to a first gas mixture comprising about 5 atomic% to about 95 atomic% of a first oxygen percentage at a first temperature, and forming a first oxide-containing portion of the oxide layer on the substrate at a first growth rate; exposing the substrate to a second gas mixture comprising a second oxygen percentage at a second temperature, and forming a second oxide-containing portion on the substrate at a second growth rate; and exposing the substrate to a third gas mixture comprising a third oxygen percentage at a third temperature, and forming a third oxide-containing portion on the substrate at a third growth rate, wherein the first growth rate is slower than each subsequent growth rate, and each growth rate after the second growth rate differs from each other by less than 50%, and wherein the third temperature is greater than 750°C.

2. The method of claim 1, further comprising the steps of: determining an estimated growth function, wherein the estimated growth function is a function of a total growth coefficient for forming the oxide layer and a time-dependent variable; determining a coefficient increment, wherein the coefficient increment is determined by dividing the total growth coefficient by a number of conditions for forming the oxide layer, wherein a first growth coefficient corresponding to forming the first oxide-containing portion is equal to the coefficient increment; and determining a growth function for each of the oxide-containing portions, wherein each subsequent oxide-containing portion has a corresponding growth coefficient that increases the coefficient increment.

3. The method as described in claim 2, wherein each growth factor depends on temperature, wherein the second temperature is selected to obtain a second growth factor, wherein the second oxygen percentage is equal to the first oxygen percentage.

4. The method as described in claim 2, wherein the growth coefficient depends on the oxygen percentage of each gas mixture, wherein the second oxygen percentage is selected to obtain a second growth coefficient, and wherein the second temperature is equal to the first temperature.

5. The method as described in claim 4, wherein each temperature is about 700°C to 800°C, wherein the first oxygen percentage is about 5 atomic% to about 30 atomic% of the first gas mixture, wherein the step of forming the second oxide-containing portion comprises the following steps: increasing the first oxygen percentage at a first oxidant rate of about 0.5% to about 10% per second for a first ramp time of about 1 second to about 20 seconds.

6. The method as described in claim 2, wherein each growth rate of each part is an average value of a derivative function of each growth function.

7. The method as described in claim 6, wherein the growth rate of each part is no more than about 3 times that of each other.

8. The method as claimed in claim 1, wherein the step of forming the second oxide-containing portion comprises the step of increasing the first temperature to the second temperature at a first heating rate during a first ramp time of about 1 second to about 10 seconds, wherein the step of forming the third oxide-containing portion comprises the step of increasing the second temperature to a third temperature at a second heating rate during a second ramp time of about 1 second to about 10 seconds, wherein the second heating rate is substantially equal to the first heating rate.

9. The method as claimed in claim 1, wherein the step of forming the first oxide-containing portion further comprises the step of maintaining the first temperature or the first oxygen percentage for a first holding time, and wherein the step of forming the second oxide-containing portion comprises the step of maintaining the second temperature or the second oxygen percentage for a second holding time.

10. The method as claimed in claim 9, wherein the first holding time is longer than a first ramp time, wherein the first ramp time is a time from the first temperature or oxygen percentage to the second temperature or second oxygen percentage.

11. The method as described in claim 9, wherein the second holding time is determined based on a predetermined growth coefficient, wherein the growth coefficient is a function of a time-dependent variable, temperature, and oxygen percentage.

12. The method as claimed in claim 1, wherein the oxide layer comprises about 90% to about 100% conformability determined by measuring the thickness of at least two portions of the oxide layer.

13. A method of forming an oxide layer on a semiconductor substrate, comprising the steps of: introducing a gas mixture into a volume of a processing chamber; increasing the volume of the processing chamber into a processing attribute under two or more attribute conditions, starting from a first condition of a plurality of conditions, wherein the step of increasing the attribute comprises the steps of: incrementally increasing from a first attribute to each attribute condition, and incrementally increasing to a final attribute, wherein each transition to a subsequent attribute condition corresponds to a respective ramp time, wherein each ramp time is from about 1 second to about 10 seconds, and wherein each ramp time is less than about 10% of a total time for forming the oxide layer; and holding each of the attribute conditions between each increment for a respective holding time, wherein each of the holding times is greater than each of the ramp times, wherein the attribute is temperature, the oxygen percentage of the gas mixture, or a combination thereof.

14. The method as described in claim 13, wherein the oxide layer is formed in a channel of the substrate having an aspect ratio of about 50:1 to about 100:

1.

15. The method as described in claim 13, wherein the step of increasing the property comprises the following steps: increasing the oxygen percentage of the gas mixture from a first oxygen percentage of about 5 atomic% to about 30 atomic% to a final oxygen percentage of about 70 atomic% to about 90 atomic%.

16. The method as described in claim 13, wherein the step of increasing the property comprises the following steps: increasing the temperature from about 20°C to about 100°C in a first ramp time of less than about 10 seconds, while maintaining about 20 atomic% to about 50 atomic% of monooxygen.

17. A method of forming an oxide layer on a substrate, comprising the steps of: determining an overall growth factor for a portion of the oxide layer used to form the oxide layer, wherein the overall growth factor is determined based on a predetermined overall thickness of the oxide layer, an overall process time for forming the oxide layer, and a predetermined conformality tolerance, wherein the predetermined conformality tolerance is determined based on deviations in the thickness of the oxide layer at two or more locations on a surface of the substrate; and determining a plurality of sub-operations and corresponding growth factors, wherein the corresponding growth factors together form a linear interpolation between zero and the overall growth factor, wherein the plurality of sub-operations includes a ramp time, a hold time, an oxygen percentage of a gas mixture used to form each portion of the oxide layer, and a temperature in each sub-operation, wherein each subsequent sub-operation in the plurality of sub-operations includes increasing the temperature, oxygen percentage, or a combination thereof, wherein each ramp time is from about 1 second to about 10 seconds and is substantially equal to each other, and each ramp time is less than each hold time.

18. The method as claimed in claim 17, wherein the step of increasing the oxygen percentage comprises the steps of: increasing the flow rate of an oxygen in the gas mixture while maintaining the same flow rate of the remaining gas in the gas mixture.

19. The method of claim 17 further comprises the step of: determining an estimated growth function, wherein the estimated growth function is a function of the total growth coefficient for forming the oxide layer at a square root of a time variable, wherein the estimated growth function is a horizontal parabolic function over time.

20. The method as described in claim 17, wherein the plurality of sub-operations comprises about 3 to about 7 sub-operations.

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