Manufacturing method of oxide layer and semiconductor device

Abstract

The invention discloses a manufacturing method of an oxide layer and a semiconductor device, relates to the technical field of semiconductors, and aims to form the oxide layer with high quality, high density, high reliability, large thickness regulation and control range and high regulation and control precision on a semiconductor structure in a low-temperature environment. The manufacturing method of the oxide layer comprises the following steps: providing a semiconductor structure; next, in a first low-temperature environment, forming a first oxide layer on the semiconductor structure; next, in a second low-temperature environment, oxygen plasma processing is carried out on the first oxide layer and a part of the semiconductor structure, so that the first oxide layer forms a second oxide layer; the compactness of the second oxide layer is greater than that of the first oxide layer. The semiconductor device comprises a semiconductor structure and a second oxide layer arranged on the semiconductor structure, and the second oxide layer is manufactured and formed by adopting the manufacturing method of the oxide layer.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for manufacturing an oxide layer and a semiconductor device. Background Art

[0002] With the continuous development of large-scale integrated circuit technology, higher requirements are placed on the oxide layer usually included in transistors. On the one hand, due to the continuous reduction in the size of transistors, the thermal budget requirements in the process of manufacturing transistors are getting higher and higher, which puts higher requirements on the process of manufacturing oxide layers; on the other hand, in order to meet the performance and reliability requirements of different transistors, the oxide layer needs to have good density and its thickness needs to be precisely controlled within a large range.

[0003] However, it is difficult to manufacture an oxide layer with high density and controllable thickness in a low-temperature environment using existing manufacturing methods, resulting in poor operating performance and reliability of semiconductor devices including the oxide layer. Summary of the invention

[0004] The object of the present invention is to provide a method for manufacturing an oxide layer and a semiconductor device, which are used to form an oxide layer with high quality, high density, high reliability, large thickness control range and high control accuracy on a semiconductor structure in a low temperature environment.

[0005] In order to achieve the above-mentioned purpose, in a first aspect, the present invention provides a method for manufacturing an oxide layer. The method for manufacturing an oxide layer comprises: first, providing a semiconductor structure. Next, in a first low-temperature environment, forming a first oxide layer on the semiconductor structure. Next, in a second low-temperature environment, performing an oxygen plasma treatment on the first oxide layer and a portion of the semiconductor structure so that the first oxide layer forms a second oxide layer; the second oxide layer has a greater density than the first oxide layer.

[0006] When the above technical solution is adopted, the semiconductor structure is first pre-oxidized in a first low-temperature environment to form a first oxide layer with a relatively low density, and to help the subsequent formation of a second oxide layer. Then, in a second low-temperature environment, an oxygen plasma oxidation process is used to react the oxygen plasma with the first oxide layer and part of the semiconductor structure to form a second oxide layer, and the second oxide layer is used as the oxide layer manufactured by the method for manufacturing an oxide layer provided by the present invention.

[0007] The use of oxygen plasma to form the second oxide layer is to ionize oxygen into oxygen plasma containing a large number of unstable chemically active substances such as oxygen ions, oxygen free radicals, and electrons through a radio frequency power supply, and then charge and accelerate the oxygen plasma through a radio frequency power supply, and the accelerated oxygen plasma directly bombards the surface of the first oxide layer and part of the semiconductor structure, and reacts with the first oxide layer and part of the semiconductor structure. Since these oxygen plasmas have stronger oxidation ability than the reactants in other oxidation processes, the first oxide layer and part of the semiconductor structure can be fully oxidized to form a relatively denser second oxide layer; at the same time, these oxygen plasmas have higher energy after being accelerated by a radio frequency power supply, can penetrate the first oxide layer, and part of the formed second oxide layer, and be injected into the semiconductor structure, oxidizing the atoms inside the semiconductor structure, so that the thickness of the formed second oxide layer has a larger adjustable range, and it is not easy to cause the problem that the thickness of the oxide layer cannot be increased due to the oxidation of the surface of the semiconductor structure; in addition, oxygen plasma obeys the gas law, and the relationship between the thickness of the oxide layer generated by the oxygen plasma treatment of the first oxide layer and part of the semiconductor structure and the treatment time can be accurately described, so the thickness of the second oxide layer can be accurately controlled by controlling the time of oxygen plasma treatment. Compared with the prior art, the method for manufacturing an oxide layer provided by the embodiment of the present invention can obtain a second oxide layer with high density, high thickness control accuracy and a large control range, and a semiconductor device including the second oxide layer has better reliability.

[0008] However, in the prior art, if the second oxide layer is formed only by oxygen plasma treatment, in order to ensure that the second oxide layer has good density, the oxygen plasma treatment needs to be carried out at a high temperature, which usually results in a higher thermal budget. In the method for manufacturing the oxide layer provided by the present invention, the semiconductor structure is first pre-oxidized in a first low-temperature environment to form a first oxide layer with relatively low density. Although the first oxide layer has low density and poor quality, it can be used to preliminarily oxidize the semiconductor structure, so that the oxygen plasma treatment does not need to start from scratch, thereby reducing the RF power, processing time and processing temperature required for oxygen plasma treatment to form the second oxide layer, so that the oxygen plasma treatment to form the second oxide layer can be carried out in a second low-temperature environment, which greatly reduces the thermal budget. And the process of forming the first oxide layer is carried out in the first low-temperature environment. Combined with the above, the total thermal budget for forming the first oxide layer and the second oxide layer is still lower than that for forming the second oxide layer only by oxygen plasma treatment. The method for manufacturing the oxide layer provided by the present invention has a lower thermal budget, which can effectively reduce the thermal damage generated by semiconductor devices including the oxide layer during the manufacturing process of the oxide layer.

[0009] As a possible implementation, the temperature of the first low temperature environment is less than or equal to 400°C.

[0010] When the above technical solution is adopted, the thermal budget of the method for manufacturing the oxide layer provided by the present invention can be further reduced.

[0011] As a possible implementation, the temperature of the second low temperature environment is less than or equal to 400°C.

[0012] When the above technical solution is adopted, the thermal budget of the method for manufacturing the oxide layer provided by the present invention can be further reduced.

[0013] As a possible implementation, forming a first oxide layer on a semiconductor structure includes: immersing the semiconductor structure in an ozone aqueous solution to oxidize the semiconductor structure to form the first oxide layer.

[0014] In the case of adopting the above technical solution, ozone water oxidation is used to pre-oxidize the semiconductor structure. Ozone water oxidation, as a chemical oxidation method, can form a loose and non-dense first oxide layer, so that when the semiconductor structure is subsequently treated with oxygen plasma, the oxygen plasma enters the first oxide layer and oxidizes the first oxide layer and part of the semiconductor structure at the same time to form a second oxide layer; and, when ozone water oxidation is used to pre-oxidize the semiconductor structure, the thickness of the first oxide layer produced is relatively low, which can avoid the thickness of the second oxide layer formed later not meeting the actual requirements when the second oxide layer is a thinner oxide layer such as an interface layer due to the excessive thickness of the first oxide layer, thereby reducing the thickness range of the oxide layer manufactured by the method for manufacturing the oxide layer provided by the present invention. And because the solution wet process is used, the temperature of the first low-temperature environment is lower, which is conducive to reducing the thermal budget of the method for manufacturing the oxide layer provided by the present invention.

[0015] As a possible implementation scheme, the concentration of ozone in the ozone aqueous solution is greater than or equal to 3 ppm and less than or equal to 100 ppm.

[0016] When the above technical solution is adopted, the concentration of ozone in the ozone aqueous solution is within the above range, which can avoid the poor density and quality of the oxide layer formed due to too low ozone concentration, and the excessively thin thickness, which leads to the need for higher energy and thus greater radio frequency power, longer processing time and higher processing temperature when the subsequent oxygen plasma treatment is used, thereby ensuring the thermal budget of the method for manufacturing the oxide layer provided by the present invention. It can also avoid the ozone in the solution from being dispersed in large quantities due to too high ozone concentration, reduce the amount of consumables used, and help control manufacturing costs.

[0017] As a possible implementation, the semiconductor structure is immersed in the ozone aqueous solution for oxidation for a time greater than or equal to 3 seconds and less than or equal to 100 seconds.

[0018] In the case of adopting the above technical solution, the oxidation time of immersing the semiconductor structure in the ozone aqueous solution is within the above range, which can avoid the first oxide layer formed due to too short oxidation time, which has poor density and poor quality, resulting in the need for higher energy and greater RF power, longer processing time and higher processing temperature when subsequently treated with oxygen plasma, thereby ensuring the thermal budget of the method for manufacturing the oxide layer provided by the present invention. It can also avoid the total amount of ozone in the solution being too much due to too long oxidation time, reduce the amount of consumables used, and help control manufacturing costs.

[0019] As a possible implementation, the thickness of the second oxide layer is greater than or equal to 0.5 nm and less than or equal to 5 nm.

[0020] When the above technical solution is adopted, the thickness of the second oxide layer can be adjusted in a wide range, and the second oxide layer can have a large application range, thereby expanding the application scope of the oxide layer manufacturing method provided by the present invention.

[0021] As a possible implementation, the treatment temperature of the oxygen plasma treatment is greater than or equal to 200° C. and less than or equal to 400° C.

[0022] When the above technical solution is adopted, the treatment temperature of the oxygen plasma treatment is within the above range, which can avoid the thickness of the second oxide layer formed not meeting the design requirements due to the treatment temperature being too low, and can also avoid the density of the second oxide layer formed not meeting the design requirements due to the treatment temperature being too low; it can also avoid a significant increase in the thermal budget due to the treatment temperature being too high, thereby ensuring the thermal budget of the oxide layer manufacturing method provided by the present invention.

[0023] As a possible implementation scheme, the radio frequency power of the oxygen plasma treatment is greater than or equal to 500W and less than or equal to 1000W.

[0024] In the case of adopting the above technical scheme, the RF power of the oxygen plasma treatment is within the above range, which can avoid the problem that the RF power is too low, resulting in the formation of a second oxide layer of a certain thickness, and the oxygen plasma energy is too low to effectively bombard the first oxide layer and the semiconductor structure, resulting in the second oxide layer formed by the oxygen plasma treatment reaching a saturation thickness and cannot be further increased, thereby ensuring the thickness control range of the oxide layer formed by the oxide layer manufacturing method provided by the present invention; it can also avoid the RF power being too low, resulting in incomplete ionization of oxygen and poor oxidizability of oxygen plasma, thereby ensuring the density and quality of the second oxide layer formed by the oxygen plasma treatment. It can also avoid excessive reflection after the oxygen plasma bombards the first oxide layer and the semiconductor structure due to excessive RF power of the oxygen plasma treatment, which damages the oxygen plasma treatment equipment, thereby ensuring the normal operation of the equipment.

[0025] As a possible implementation, the treatment time of the oxygen plasma treatment is greater than or equal to 5 seconds and less than or equal to 1 hour.

[0026] When the above technical solution is adopted, the treatment time of the oxygen plasma treatment is within the above range, which can avoid the compactness and thickness of the second oxide layer formed due to too short a treatment time failing to meet the design requirements, thereby ensuring the performance of the oxide layer manufactured by the method for manufacturing an oxide layer provided by the present invention. It can also avoid a substantial increase in the thermal budget due to too long a treatment time of the oxygen plasma treatment, thereby ensuring the thermal budget of the method for manufacturing an oxide layer provided by the present invention.

[0027] As a possible implementation, the second oxide layer includes an interface oxide layer.

[0028] When the above technical solution is adopted, the second oxide layer manufactured by the method for manufacturing an oxide layer provided by the present invention has a smaller thickness, and the method for manufacturing an oxide layer provided by the present invention can be used as a method for manufacturing an interface oxide layer.

[0029] As a possible implementation, the material of the semiconductor structure includes silicon.

[0030] When the above technical solution is adopted, the method for manufacturing the oxide layer provided by the present invention has good compatibility with the most common material currently available, namely silicon, and can expand the scope of application of the method for manufacturing the oxide layer provided by the present invention.

[0031] As a possible implementation, the semiconductor structure includes a source region, a drain region, and a channel region between the source region and the drain region. The two sides of the channel region along its length direction are in contact with the source region and the drain region respectively. The second oxide layer is formed on the periphery of the channel region.

[0032] When the above technical solution is adopted, since the second oxide layer manufactured by the method for manufacturing an oxide layer provided by the present invention has a smaller thickness, the method for manufacturing an oxide layer provided by the present invention can be used as a method for manufacturing an interface layer.

[0033] In a second aspect, the present invention provides a semiconductor device. The semiconductor device includes: a semiconductor structure, and a second oxide layer disposed on the semiconductor structure, wherein the second oxide layer is manufactured by the manufacturing method provided in the first aspect. The beneficial effects of the semiconductor device provided by the present invention can be referred to the relevant description of the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0035] Figure 1 A flow chart of a method for manufacturing an oxide layer provided in an embodiment of the present invention;

[0036] Figure 2 A schematic diagram of a semiconductor structure is provided in an embodiment of the present invention;

[0037] Figure 3 A schematic diagram of forming a first oxide layer in an embodiment of the present invention;

[0038] Figure 4 A schematic diagram of forming a second oxide layer in an embodiment of the present invention;

[0039] Figure 5 is a graph showing the thickness of the second oxide layer increased compared to the first oxide layer and the oxygen plasma treatment time in an embodiment of the present invention;

[0040] Figure 6 Schematic diagram showing that the density and reliability of the second oxide layer are increased compared to the first oxide layer in an embodiment of the present invention.

[0041] Reference numerals:

[0042] 100-semiconductor structure, 200-first oxide layer,

[0043] 300-Second oxide layer. DETAILED DESCRIPTION

[0044] In order to make the technical problems, technical solutions and beneficial effects to be solved by the embodiments of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not used to limit the embodiments of the present invention.

[0045] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0046] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. "Several" means one or more, unless otherwise clearly and specifically defined.

[0047] In the description of the embodiments of the present invention, it should be understood that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the embodiments of the present invention.

[0048] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0049] The purpose of the embodiments of the present invention is to provide a method for manufacturing an oxide layer and a semiconductor device, which are used to form an oxide layer with high quality, high density, large thickness control range and high control accuracy on a semiconductor structure in a low temperature environment.

[0050] In order to achieve the above-mentioned purpose, in a first aspect, an embodiment of the present invention provides a method for manufacturing an oxide layer. The method for manufacturing an oxide layer comprises: first, referring to Figure 1 , providing a semiconductor structure 100. Next, please refer to Figure 2 , a first oxide layer 200 is formed on the semiconductor structure 100 in a first low temperature environment. Next, please refer to Figure 3 , in a second low temperature environment, the first oxide layer 200 and a portion of the semiconductor structure 100 are subjected to oxygen plasma treatment so that the first oxide layer 200 forms a second oxide layer 300 ; the density of the second oxide layer 300 is greater than the density of the first oxide layer 200 .

[0051] When using the above technical solution, please refer to Figure 2 , the semiconductor structure 100 is pre-oxidized in a first low temperature environment to form a first oxide layer 200 with relatively low density. The first oxide layer 200 can help the subsequent formation of the second oxide layer 300. Please refer to Figure 3 In a second low temperature environment, an oxygen plasma oxidation process is used to make the oxygen plasma react with the first oxide layer 200 and a portion of the semiconductor structure 100 to form a second oxide layer 300. The second oxide layer 300 is an oxide layer manufactured by the oxide layer manufacturing method provided in an embodiment of the present invention.

[0052] The use of oxygen plasma to form the second oxide layer is to excite oxygen into oxygen plasma containing a large number of unstable chemically active substances such as oxygen ions, oxygen free radicals, and electrons before the reaction, and then charge and accelerate the oxygen plasma through a radio frequency power supply, and the accelerated oxygen plasma directly bombards the surface of the first oxide layer and part of the semiconductor structure, and reacts with the first oxide layer and part of the semiconductor structure. Since these oxygen plasmas have stronger oxidation ability than the reactants in other oxidation processes, the first oxide layer and part of the semiconductor structure can be fully oxidized to form a relatively denser second oxide layer; at the same time, these oxygen plasmas have higher energy after radio frequency acceleration, can penetrate the first oxide layer, and part of the formed second oxide layer, and be injected into the semiconductor structure to oxidize the atoms inside the semiconductor structure, so that the thickness of the formed second oxide layer has a larger adjustable range, and it is not easy to cause the problem that the thickness of the oxide layer cannot be increased due to the oxidation of the surface of the semiconductor structure; in addition, oxygen plasma obeys the gas law, and the relationship between the thickness of the oxide layer generated by oxygen plasma treatment of the first oxide layer and part of the semiconductor structure and the treatment time can be accurately described, so the thickness of the second oxide layer can be accurately controlled by controlling the time of oxygen plasma treatment. Compared with the prior art, the method for manufacturing an oxide layer provided by the embodiment of the present invention can obtain a second oxide layer with high density, high thickness control accuracy and a large control range.

[0053] However, in the prior art, if the second oxide layer is formed only by oxygen plasma treatment, in order to ensure that the second oxide layer has good density, the oxygen plasma treatment needs to be carried out at a high temperature, which usually results in a higher thermal budget. In the method for manufacturing the oxide layer provided in an embodiment of the present invention, the semiconductor structure is first pre-oxidized in a first low temperature environment to form a first oxide layer with relatively low density. Although the first oxide layer has low density and poor quality, it can be used to preliminarily oxidize the semiconductor structure, so that the oxygen plasma treatment does not need to start from scratch, thereby reducing the RF power, processing time and processing temperature required for oxygen plasma treatment to form the second oxide layer, so that the oxygen plasma treatment to form the second oxide layer can be carried out in a second low temperature environment, which greatly reduces the thermal budget. And the process of forming the first oxide layer is carried out in the first low temperature environment. Combined with the above, the total thermal budget for forming the first oxide layer and the second oxide layer is still lower than that for forming the second oxide layer only by oxygen plasma treatment. The method for manufacturing the oxide layer provided in an embodiment of the present invention has a lower thermal budget, which can effectively reduce the thermal damage generated by the semiconductor device including the oxide layer in the process of manufacturing the oxide layer.

[0054] In addition, in a low temperature environment, the density of the oxide layer manufactured by the prior art is low, which will lead to a reduction in the reliability of the semiconductor device including the oxide layer. For example, there are a large number of defects in the oxide layer with a lower density, which will capture / decapture channel carriers and affect the device static electricity and carrier transport in the channel, thereby causing the bias temperature instability (BTI) problem. In order to solve this problem, the prior art is usually implemented by a high-temperature treatment method such as high-temperature annealing. Although this method solves the problem of poor density of the oxide layer, the high temperature will cause thermal damage to the semiconductor structure, and the thickness of the oxide layer has a poor controllable range and control accuracy, so that the performance and reliability of the semiconductor device including the oxide layer are still poor. The embodiment of the present invention provides a method for manufacturing an oxide layer, which is to improve the density of the pre-formed first oxide layer by combining pre-oxidation and oxygen plasma treatment in a low-temperature environment, and at the same time, the thickness of the second oxide layer is precisely controlled by adjusting the process parameters of the oxygen plasma treatment. Not only is a second oxide layer with higher density obtained, but it also overcomes the technical prejudice in the prior art that the density of the oxide layer manufactured by low-temperature method must be poor, thereby ensuring the reliability of semiconductor devices including the second oxide layer.

[0055] In the actual manufacturing process, the specific structure of the semiconductor structure is not specifically limited by the embodiment of the present invention and can be determined according to actual needs. Specifically, the semiconductor structure can be a semiconductor substrate on which no structure is formed. Alternatively, the semiconductor structure can also be a structure formed with some corresponding functions and made of at least semiconductor materials. The specific structure of the semiconductor structure can be determined according to the actual application scenario, as long as an oxide layer needs to be formed thereon.

[0056] For example, please refer to Figure 2 The semiconductor substrate 100 on which no structure is formed may be a bare wafer.

[0057] Exemplarily, the semiconductor structure may include a source region, a drain region, and a channel region between the source region and the drain region. The two sides of the channel region along its own length direction are in contact with the source region and the drain region respectively. The second oxide layer is formed on the periphery of the channel region.

[0058] When the above technical solution is adopted, since the second oxide layer manufactured by the method for manufacturing an oxide layer provided in the embodiment of the present invention has a smaller thickness, the method for manufacturing an oxide layer provided in the embodiment of the present invention can be used as a method for manufacturing an interface layer.

[0059] Regarding the material of the semiconductor structure, the embodiment of the present invention does not limit the material of the semiconductor structure, and can be determined according to the specific structure type included in the semiconductor structure and actual needs, as long as it can be applied to the manufacturing method of the oxide layer provided in the embodiment of the present invention. For example, the material of the semiconductor structure may include silicon, germanium, germanium silicon or any other possible semiconductor material.

[0060] Optionally, the material of the semiconductor structure includes silicon.

[0061] When the above technical solution is adopted, the method for manufacturing the oxide layer provided by the embodiment of the present invention has good compatibility with the most common existing material, namely silicon, and can expand the scope of application of the method for manufacturing the oxide layer provided by the embodiment of the present invention.

[0062] As for the density of the first oxide layer, as a pre-oxidation layer of the second oxide layer, the density of the first oxide layer needs to be lower than the density of the second oxide layer, so that when the second oxide layer is subsequently formed by oxygen plasma treatment, the oxygen plasma enters the relatively loose first oxide layer and processes the first oxide layer and part of the semiconductor structure to form a second oxide layer.

[0063] As for the thickness of the first oxide layer, the embodiment of the present invention does not limit the thickness of the first oxide layer, and can be determined according to the material of the semiconductor structure, the thickness of the second oxide layer and actual needs, as long as it can be applied to the oxide layer manufacturing method provided in the embodiment of the present invention.

[0064] Exemplarily, the first oxide layer serves as a pre-oxidation layer for the second oxide layer, and the first oxide layer may have a relatively thin thickness to meet various requirements of the second oxide layer formed subsequently, such as the thickness of the second oxide layer, the thermal budget for forming the second oxide layer, etc.

[0065] In an actual manufacturing process, the thickness of the second oxide layer formed from the first oxide layer is not specifically limited in the embodiment of the present invention and can be determined according to actual needs.

[0066] Specifically, since the second oxide layer is partially formed by the semiconductor structure, the thickness of the second oxide layer can be determined according to the material of the semiconductor structure and the specific structure type included in the semiconductor structure. Alternatively, the thickness of the second oxide layer can also be determined according to the thermal budget set for the manufacturing method provided by the embodiment of the present invention, and actual needs. Alternatively, since the first oxide layer serves as a pre-oxidation layer for the second oxide layer, the thickness of the second oxide layer can be greater than or equal to the thickness of the first oxide layer.

[0067] Exemplarily, the thickness of the second oxide layer manufactured by the oxide layer manufacturing method provided in the embodiment of the present invention is greater than or equal to 0.5nm and less than or equal to 5nm. Specifically, the thickness of the second oxide layer can be 0.5nm, 1nm, 2nm, 3nm, 4nm or 5nm.

[0068] When the above technical solution is adopted, the thickness of the second oxide layer can be adjusted in a wide range, and the second oxide layer can have a large application range, thereby expanding the application scope of the oxide layer manufacturing method provided in the embodiment of the present invention.

[0069] As for the purpose of the second oxide layer, it can be determined according to the parameters of the second oxide layer manufactured by the method for manufacturing an oxide layer provided in an embodiment of the present invention. For example, the second oxide layer can be a passivation layer, a doping barrier layer or an interface oxide layer.

[0070] Optionally, the second oxide layer may be an interface oxide layer. The second oxide layer manufactured by the method for manufacturing an oxide layer provided in the embodiment of the present invention has a relatively small thickness, and the method for manufacturing an oxide layer provided in the embodiment of the present invention may be used as a method for manufacturing an interface oxide layer.

[0071] For details on the density and quality improvement of the second oxide layer after oxygen plasma treatment compared to the first oxide layer, please refer to Figure 6 , the first oxide layer and the second oxide layer are both used as the dielectric layer of the metal-oxide-semiconductor capacitor. At 125°C, the flat-band voltage degradation of the capacitor in which the first oxide layer and the second oxide layer are both used as the dielectric layer of the metal-oxide-semiconductor capacitor after 1000 seconds of constant electric field stress is compared. The flat-band voltage degradation of the capacitor in which the second oxide layer is used as the dielectric layer of the metal oxide semiconductor capacitor is smaller, which means that the second oxide layer has fewer native defects and defects generated during the stress process, that is, the second oxide layer has better density, quality and reliability. The second oxide layer manufactured in the embodiment of the present invention at least meets the aforementioned density requirements.

[0072] In the actual manufacturing process, the specific temperature of the first low-temperature environment can be determined according to the specific structure and materials of the semiconductor structure, as well as the actual needs, and is not specifically limited here. Specifically, for the first low-temperature environment, the following conditions must be met: First, the thermal budget for forming the first oxide layer in the first low-temperature environment and the thermal budget for forming the second oxide layer in the second low-temperature environment must not exceed the requirements for the thermal budget when the oxide layer manufacturing method provided in the embodiment of the present invention is specifically applied; second, the first oxide layer must be able to be formed within this temperature range, and the first oxide layer must meet the density requirements of the subsequent oxygen plasma treatment.

[0073] Exemplarily, the temperature of the first low temperature environment may be less than or equal to 400° C. For example, the temperature of the first low temperature environment may be 50° C., 80° C., 100° C., 120° C., 150° C., 180° C., 200° C., 220° C., 260° C., 280° C., 300° C., 320° C., 340° C., 360° C., 380° C. or 400° C., etc.

[0074] The embodiment of the present invention does not specifically limit the method for forming the first oxide layer on the semiconductor structure, as long as the first oxide layer that meets the requirements of its density and thickness during the subsequent oxygen plasma treatment can be formed in the first low temperature environment. Exemplarily, the method for forming the first oxide layer on the semiconductor structure includes a liquid phase deposition (LPD) method, a low temperature chemical vapor deposition method, or an ozone aqueous solution method.

[0075] Optionally, the method for forming the first oxide layer on the semiconductor structure is an ozone aqueous solution method. Specifically, the method for forming the first oxide layer on the semiconductor structure by the ozone aqueous solution method is to immerse the semiconductor structure in an ozone aqueous solution to oxidize the semiconductor structure to form the first oxide layer.

[0076] In the case of adopting the above technical solution, the semiconductor structure is pre-oxidized by ozone water oxidation, which can form a loose and non-dense first oxide layer, so that when the semiconductor structure is subsequently treated with oxygen plasma, the oxygen plasma enters the first oxide layer and oxidizes the first oxide layer and part of the semiconductor structure at the same time to form a second oxide layer; and, the semiconductor structure is pre-oxidized by ozone water oxidation, and the thickness of the first oxide layer produced is relatively low, which can avoid the thickness of the second oxide layer formed later not meeting the actual requirements when the second oxide layer is a thinner oxide layer such as an interface layer due to the excessive thickness of the first oxide layer, thereby reducing the thickness range of the oxide layer manufactured by the method for manufacturing the oxide layer provided in the embodiment of the present invention. And because the solution wet process is used, the temperature of the first low-temperature environment is lower, which is conducive to reducing the thermal budget of the method for manufacturing the oxide layer provided in the embodiment of the present invention.

[0077] In addition, when the semiconductor structure includes the above-mentioned source region, drain region and channel region, the second oxide layer serves as an interface layer, and the first oxide layer formed by pre-oxidation of the semiconductor structure using ozone water oxidation is relatively thin, which is conducive to achieving a smaller thickness of the second oxide layer, thereby realizing the manufacture of a thinner interface layer under low temperature conditions.

[0078] As a possible implementation, the concentration of ozone in the ozone aqueous solution is greater than or equal to 3 ppm and less than or equal to 100 ppm. For example, the concentration of ozone in the ozone aqueous solution may be 3 ppm, 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm or 100 ppm, etc.

[0079] When the above technical solution is adopted, the concentration of ozone in the ozone aqueous solution is within the above range, which can avoid the poor density, poor quality and too thin thickness of the oxide layer formed due to too low ozone concentration, resulting in the need for higher energy in the subsequent oxygen plasma treatment, thereby requiring greater RF power, longer processing time and higher processing temperature, thereby ensuring the thermal budget of the method for manufacturing the oxide layer provided by the embodiment of the present invention. It can also avoid the ozone in the solution from being dispersed in large quantities due to too high ozone concentration, reduce the use of consumables, and help control manufacturing costs.

[0080] As a possible implementation, the oxidation time of immersing the semiconductor structure in the ozone aqueous solution is greater than or equal to 3 seconds and less than or equal to 100 seconds. For example, the oxidation time of immersing the semiconductor structure in the ozone aqueous solution can be 3 seconds, 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, 60 seconds, 70 seconds, 80 seconds, 90 seconds or 100 seconds.

[0081] When the above technical solution is adopted, the oxidation time of the semiconductor structure immersed in the ozone aqueous solution is within the above range, which can avoid the first oxide layer formed due to too short oxidation time, which has poor density and poor quality, resulting in the need for higher energy and greater RF power, longer processing time and higher processing temperature when subsequently treated with oxygen plasma, thereby ensuring the thermal budget of the method for manufacturing the oxide layer provided by the embodiment of the present invention. It can also avoid the total amount of ozone released from the solution due to too long oxidation time, reduce the amount of consumables used, and help control manufacturing costs.

[0082] As for the temperature range of the second low temperature environment, its specific temperature can be determined according to the specific structure and material of the semiconductor structure, the density and thickness requirements of the second oxide layer, and the actual needs, and is not specifically limited here. Specifically, the temperature range of the second low temperature environment must meet the following conditions: First, the thermal budget for forming the first oxide layer under the first low temperature environment and the thermal budget for forming the second oxide layer under the second low temperature environment must not exceed the requirements for the thermal budget when the oxide layer manufacturing method provided by the embodiment of the present invention is specifically applied; second, the second oxide layer formed by oxygen plasma treatment within this temperature range must meet the density and thickness requirements mentioned above.

[0083] Exemplarily, the temperature of the second low temperature environment is less than or equal to 400° C. For example, the temperature of the second low temperature environment may be 50° C., 80° C., 100° C., 120° C., 150° C., 180° C., 200° C., 220° C., 260° C., 280° C., 300° C., 320° C., 340° C., 360° C., 380° C. or 400° C., etc.

[0084] When the above technical solution is adopted, the treatment temperature of the oxygen plasma treatment is within the above range, which can avoid the thickness of the second oxide layer formed not meeting the above requirements due to the treatment temperature being too low, and can also avoid the density of the second oxide layer formed not meeting the above requirements due to the treatment temperature being too low. In addition, the treatment temperature of the oxygen plasma treatment is within the above range, which can also avoid a significant increase in the thermal budget due to the treatment temperature being too high, thereby ensuring the thermal budget of the method for manufacturing the oxide layer provided by the embodiment of the present invention.

[0085] As for the RF power of the oxygen plasma treatment, in the oxide layer manufacturing method provided by the embodiment of the present invention, the RF power of the oxygen plasma treatment is greater than or equal to 500 W and less than or equal to 1000 W. For example, the RF power of the oxygen plasma treatment can be 500 W, 600 W, 700 W, 800 W, 900 W, or 1000 W.

[0086] In the case of adopting the above technical solution, the RF power of the oxygen plasma treatment is within the above range, which can avoid the problem that the RF power is too low, resulting in the formation of a second oxide layer of a certain thickness, and the oxygen plasma energy is too low to effectively bombard the first oxide layer and the semiconductor structure, resulting in the second oxide layer formed by the oxygen plasma treatment reaching a saturation thickness and cannot be further increased, thereby ensuring the thickness control range of the oxide layer formed by the oxide layer manufacturing method provided in the above embodiment of the present invention; it can also avoid the RF power being too low, resulting in incomplete ionization of oxygen and poor oxidizability of oxygen plasma, thereby ensuring that the second oxide layer formed by the oxygen plasma treatment has the density and quality that meet the above requirements. It can also avoid excessive reflection after the oxygen plasma bombards the first oxide layer and the semiconductor structure due to excessive RF power of the oxygen plasma treatment, which damages the oxygen plasma treatment equipment, thereby ensuring the normal operation of the equipment.

[0087] As for the processing time of the oxygen plasma treatment, in the oxide layer manufacturing method provided by the embodiment of the present invention, the processing time of the oxygen plasma treatment is greater than or equal to 5 seconds and less than or equal to 1 hour.

[0088] When the above technical solution is adopted, the treatment time of the oxygen plasma treatment is within the above range, which can avoid the situation that the density and thickness of the second oxide layer formed cannot meet the above requirements due to too short a treatment time, thereby ensuring the performance of the oxide layer manufactured by the method for manufacturing an oxide layer provided in the embodiment of the present invention. It can also avoid a substantial increase in the thermal budget due to too long a treatment time of the oxygen plasma treatment, thereby ensuring the thermal budget of the method for manufacturing an oxide layer provided in the embodiment of the present invention.

[0089] In addition, the relationship between the increased thickness of the second oxide layer compared to the first oxide layer and the treatment time of the oxygen plasma treatment can be accurately described, so the thickness of the second oxide layer can be accurately controlled by controlling the time of the oxygen plasma treatment. For example, please refer to Figure 5 , when the RF power is 900W and the treatment temperature is 250°C, the thickness of the second oxide layer increased compared to the first oxide layer and the time of oxygen plasma treatment can be accurately described. Figure 5 It can be seen that the thickness of the oxide layer manufactured by the method for manufacturing the oxide layer provided in the embodiment of the present invention can be controlled in a large range and with high control accuracy.

[0090] In a second aspect, an embodiment of the present invention provides a semiconductor device, characterized in that it includes: a semiconductor structure, and a second oxide layer disposed on the semiconductor structure, wherein the second oxide layer is manufactured by the manufacturing method provided in the first aspect. The beneficial effects of the semiconductor device provided by the embodiment of the present invention can be referred to the relevant description of the first aspect, and will not be repeated here.

[0091] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0092] The above is only a specific implementation of the embodiment of the present invention, but the protection scope of the embodiment of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the embodiment of the present invention, which should be included in the protection scope of the embodiment of the present invention. Therefore, the protection scope of the embodiment of the present invention should be based on the protection scope of the claims.

Claims

1. A method for manufacturing an oxide layer, characterized in that: include: Providing a semiconductor structure; forming a first oxide layer on the semiconductor structure in a first low temperature environment; In a second low temperature environment, the first oxide layer and a portion of the semiconductor structure are subjected to oxygen plasma treatment to obtain a second oxide layer; the density of the second oxide layer is greater than the density of the first oxide layer.

2. The method for manufacturing an oxide layer according to claim 1, characterized in that: The temperature of the first low temperature environment and / or the second low temperature environment is less than or equal to 400°C.

3. The method for manufacturing an oxide layer according to claim 1, characterized in that: The forming of the first oxide layer on the semiconductor structure comprises: immersing the semiconductor structure in an ozone aqueous solution to oxidize the semiconductor structure to form the first oxide layer.

4. The method for manufacturing an oxide layer according to claim 3, characterized in that: The concentration of ozone in the ozone aqueous solution is greater than or equal to 3 ppm and less than or equal to 100 ppm; And / or, the oxidation time of immersing the semiconductor structure in the ozone aqueous solution is greater than or equal to 3 seconds and less than or equal to 100 seconds.

5. The method for manufacturing an oxide layer according to claim 1, characterized in that: The thickness of the second oxide layer is greater than or equal to 0.5 nm and less than or equal to 5 nm.

6. The method for manufacturing an oxide layer according to claim 1, characterized in that: The treatment temperature of the oxygen plasma treatment is greater than or equal to 200° C. and less than or equal to 300° C.

7. The method for manufacturing an oxide layer according to claim 1, characterized in that: The radio frequency power of the oxygen plasma treatment is greater than or equal to 500W and less than or equal to 1000W.

8. The method for manufacturing an oxide layer according to claim 1, characterized in that: The treatment time of the oxygen plasma treatment is greater than or equal to 5 seconds and less than or equal to 1 hour.

9. The method for manufacturing an oxide layer according to claim 1, characterized in that: The second oxide layer includes an interface oxide layer; and / or, the material of the semiconductor structure includes silicon; And / or, the semiconductor structure includes a source region, a drain region, and a channel region located between the source region and the drain region; the channel region is in contact with the source region and the drain region on both sides along its own length direction; and the second oxide layer is formed on the periphery of the channel region.

10. A semiconductor device, characterized in that: include: A semiconductor structure, and a second oxide layer arranged on the semiconductor structure, wherein the second oxide layer is manufactured by the manufacturing method according to any one of claims 1 to 9.

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