Current ratio regulation method and apparatus, wafer deposition apparatus

Abstract

The application discloses a current ratio adjusting method and device and a wafer deposition device. The current ratio adjusting method is applied to wafer deposition. The current ratio adjusting method comprises the following steps: determining a current ratio interval, wherein a first end point of the current ratio interval is a minimum current ratio, and a second end point of the current ratio interval is a maximum current ratio; obtaining first thickness reduction data, wherein the first thickness reduction data is thickness reduction data of a wafer with a first film layer deposited at a middle current ratio of the current ratio interval after acid washing; when the first thickness reduction data does not meet a set condition, determining that the middle current ratio is a new minimum current ratio or a new maximum current ratio; and repeating the above steps until the first thickness reduction data meets the set condition, and taking the middle current ratio corresponding to the first thickness reduction data meeting the set condition as a target current ratio. The application can find a suitable current ratio in a small number of adjustment times, the adjustment direction is clear, and the target current ratio obtained through adjustment is accurate and high.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a current ratio adjustment method and apparatus, and a wafer deposition equipment. Background Technology

[0002] In some thin film deposition processes (such as chemical vapor deposition), heating devices are required. One type of heating device heats both the inner and outer rings simultaneously. However, because the thermal conductivity of the inner and outer parts is different, the current ratio (outer ring current to inner ring current) needs to be adjusted to keep the temperature of different areas of the wafer as consistent as possible, thereby making the film density in different areas of the wafer tend to be the same.

[0003] In related technologies, the current ratio between the inner and outer rings is usually adjusted using temperature data from only one location point.

[0004] However, the thermal conductivity varies in different regions of a wafer, so temperature data at one location is difficult to represent the temperature conditions in different regions of the wafer, resulting in poor accuracy of the adjusted current ratio.

[0005] In view of the above-mentioned technical problems, the present invention provides a new current ratio adjustment method and apparatus, and a wafer deposition equipment. Summary of the Invention

[0006] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0007] To address the existing problems, this application provides a current ratio adjustment method applied to wafer deposition. The current ratio adjustment method includes: determining a current ratio range, where the first endpoint of the current ratio range is the minimum current ratio and the second endpoint is the maximum current ratio; acquiring first thickness reduction data, where the first thickness reduction data is the thickness reduction data of the first film layer deposited on a wafer at the intermediate current ratio within the current ratio range after acid washing; when the first thickness reduction data does not meet a set condition, determining the intermediate current ratio as a new minimum current ratio or a new maximum current ratio; repeating the above steps until the first thickness reduction data meets the set condition, and using the intermediate current ratio corresponding to the first thickness reduction data meeting the set condition as the target current ratio.

[0008] In one embodiment of this application, obtaining the first thickness reduction data includes: after depositing the first film layer on the wafer at the middle current ratio of the current ratio range, obtaining the original thickness data of the first film layer; after acid washing the wafer on which the first film layer is deposited, obtaining the remaining thickness data of the first film layer; and obtaining the first thickness reduction data by subtracting the original thickness data from the remaining thickness data.

[0009] In one embodiment of this application, obtaining the original thickness data of the first film layer includes: performing thickness detection on the first film layer at multiple points to obtain the original thickness data; obtaining the remaining thickness data of the first film layer includes: performing thickness detection on the remaining portion of the first film layer at the multiple points to obtain the remaining thickness data.

[0010] In one embodiment of this application, the setting conditions include: the difference between the first thickness reduction data and the set thickness reduction data is not greater than a set threshold; and / or the color difference between the wafer test pattern generated based on the first thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is not greater than a color difference threshold.

[0011] In one embodiment of this application, determining the intermediate current ratio as a new minimum current ratio or a new maximum current ratio includes: obtaining a first difference data by subtracting the second thickness reduction data and the first thickness reduction data; obtaining a second difference data by subtracting the third thickness reduction data and the first thickness reduction data; determining the intermediate current ratio as a new minimum current ratio when the first difference data is greater than the second difference data, or determining the intermediate current ratio as a new maximum current ratio when the first difference data is less than the second difference data; wherein, the second thickness reduction data is the thickness reduction data of the second film layer after acid washing on a wafer with a second film layer deposited at the first end current ratio of the current ratio range; the third thickness reduction data is the thickness reduction data of the third film layer after acid washing on a wafer with a third film layer deposited at the second end current ratio of the current ratio range.

[0012] In one embodiment of this application, determining the intermediate current ratio as a new minimum current ratio or a new maximum current ratio includes: determining a first color difference data between a second wafer test pattern and a first wafer test pattern; determining a second color difference data between a third wafer test pattern and the first wafer test pattern; determining the intermediate current ratio as a new minimum current ratio when the first color difference data is less than the second color difference data, or determining the intermediate current ratio as a new maximum current ratio when the first color difference data is greater than the second color difference data; wherein, the first wafer test pattern is generated based on the first thickness reduction data; the second wafer test pattern is generated based on the second thickness reduction data, the second thickness reduction data being the thickness reduction data of the second film layer after acid washing on a wafer with a second film layer deposited at the first endpoint current ratio of the current ratio range; the third wafer test pattern is generated based on the third thickness reduction data, the third thickness reduction data being the thickness reduction data of the third film layer after acid washing on a wafer with a third film layer deposited at the second endpoint current ratio of the current ratio range.

[0013] In one embodiment of this application, the wafer deposition process is chemical vapor deposition.

[0014] According to another aspect of this application, a current ratio adjustment method is provided, the current ratio adjustment method being applied to wafer deposition, the current ratio adjustment method comprising: establishing a current ratio prediction model based on at least one set of wafer deposition data, each set of wafer deposition data including a current ratio and a wafer with a film deposited at the current ratio, and the thickness reduction data of the film after acid washing; inputting thickness reduction data that meets set conditions into the current ratio prediction model, and using the current ratio corresponding to the thickness reduction data output by the current ratio prediction model that meets the set conditions as the target current ratio.

[0015] According to another aspect of this application, a current ratio adjustment device is provided, the current ratio adjustment device being applied to wafer deposition, the current ratio adjustment device comprising a memory and a processor, the memory storing a computer program executed by the processor, characterized in that, when executed by the processor, the computer program causes the processor to perform the current ratio adjustment method described in any one of the above descriptions.

[0016] According to another aspect of this application, a wafer deposition apparatus is provided, the wafer deposition apparatus including a wafer heating element and the aforementioned current ratio adjustment device, the wafer heating element including an outer ring heating element and an inner ring heating element, the inner ring heating element being disposed inside the outer ring heating element, and the current ratio adjustment device being used to adjust the current ratio between the outer ring heating element and the inner ring heating element.

[0017] In one embodiment of this application, the wafer deposition equipment is a chemical vapor deposition apparatus.

[0018] The current ratio adjustment method and apparatus, and wafer deposition equipment of this application can find a suitable current ratio with fewer adjustments. Moreover, by using whether the first thickness reduction data meets the set conditions as the adjustment direction, the adjustment direction is clear and the target current ratio obtained by adjustment is highly accurate. Attached Figure Description

[0019] The following drawings, which are incorporated herein by reference as part of this invention, are provided for understanding the invention. The drawings illustrate embodiments of the invention and their descriptions, serving to explain the principles of the invention.

[0020] In the attached image:

[0021] Figure 1 A schematic flowchart of a current ratio adjustment method according to an embodiment of this application is shown;

[0022] Figure 2 A schematic diagram illustrating thickness measurement using multiple points according to an embodiment of this application is shown;

[0023] Figure 3 A schematic diagram illustrating thickness measurement using multiple points according to another embodiment of this application is shown;

[0024] Figure 4 A first wafer test pattern is shown, generated according to an embodiment of this application based on first thickness reduction data corresponding to the unadjusted intermediate current ratio.

[0025] Figure 5 A first wafer test pattern is shown, generated according to an embodiment of the present application based on first thickness reduction data corresponding to an adjusted intermediate current ratio.

[0026] Figure 6 A schematic flowchart of a current ratio adjustment method according to another embodiment of this application is shown;

[0027] Figure 7 A schematic block diagram of a current ratio adjustment device according to an embodiment of this application is shown. Detailed Implementation

[0028] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0029] It should be understood that the invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0030] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0031] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0033] In some thin film deposition processes (such as chemical vapor deposition), heating devices are required. One type of heating device heats both the inner and outer rings simultaneously. However, because the thermal conductivity of the inner and outer parts is different, the current ratio (outer ring current to inner ring current) needs to be adjusted to keep the temperature of different areas of the wafer as consistent as possible, thereby making the film density in different areas of the wafer tend to be the same.

[0034] In related technologies, the current ratio between the inner and outer rings is usually adjusted using temperature data from only one location point.

[0035] However, the thermal conductivity varies in different regions of a wafer. Therefore, temperature data at one location is difficult to represent the temperature conditions in different regions of the wafer. This adjustment method often requires a large number of adjustments and it is difficult to have a clear direction for adjustment, resulting in poor accuracy of the current ratio obtained from the adjustment.

[0036] To address the aforementioned problems, this application provides a current ratio adjustment method applied to wafer deposition. The current ratio adjustment method includes: determining a current ratio range, where the first endpoint of the current ratio range is the minimum current ratio and the second endpoint is the maximum current ratio; acquiring first thickness reduction data, where the first thickness reduction data is the thickness reduction data of the first film layer deposited on a wafer at the intermediate current ratio within the current ratio range after acid washing; when the first thickness reduction data does not meet a set condition, determining the intermediate current ratio as a new minimum current ratio or a new maximum current ratio; repeating the above steps until the first thickness reduction data meets the set condition, and using the intermediate current ratio corresponding to the first thickness reduction data meeting the set condition as the target current ratio.

[0037] According to the current ratio adjustment method of this application, the appropriate current ratio can be found by iteratively searching within the current ratio range using the bisection method with fewer adjustment times. Moreover, the adjustment direction is clearly defined by whether the data of the first thickness reduction meets the set conditions, and the target current ratio obtained by adjustment is highly accurate.

[0038] To fully understand this invention, detailed steps and structures will be presented in the following description to illustrate the technical solution proposed by this invention. Preferred embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0039] Example 1

[0040] The following is for reference. Figure 1 A current ratio adjustment method according to an embodiment of this application is described. For example... Figure 1 As shown, the current ratio adjustment method 100 applied to wafer deposition may include the following steps:

[0041] In step S101, the current ratio range is determined, with the first endpoint of the current ratio range being the minimum current ratio and the second endpoint being the maximum current ratio.

[0042] In step S102, first thickness reduction data is obtained. The first thickness reduction data is the thickness reduction data of the first film layer after acid washing on a wafer with a first film layer deposited at the middle current ratio in the current ratio range.

[0043] In step S103, when the first thickness reduction data does not meet the set conditions, the intermediate current ratio is determined to be either the new minimum current ratio or the new maximum current ratio.

[0044] In step S104, the above steps are repeated until the first thickness reduction data meets the set conditions, and the intermediate current ratio corresponding to the first thickness reduction data meeting the set conditions is taken as the target current ratio.

[0045] It is understandable that in the initial stage of current ratio adjustment, there exists a reasonable safe current ratio range, i.e., the initial current ratio interval. The current ratio adjustment method 100 described above iteratively searches within the safe current ratio range based on the idea of ​​the bisection method to obtain the target current ratio.

[0046] Specifically, after determining the initial current ratio range, the wafer is deposited with a film at the middle current ratio of this current ratio range to obtain the first film.

[0047] Then, the wafer with the first film layer deposited is acid-washed, and the reduction in the thickness of the first film layer after acid washing is taken as the first thickness reduction data. Since the density of the film layer and its acid resistance are positively correlated, the denser the film layer, the more resistant it is to acid corrosion, and the greater the remaining thickness of the first film layer on the wafer; conversely, the more porous the film layer, the smaller the remaining thickness of the first film layer on the wafer. Therefore, the density of the film layer can be reflected by the first thickness reduction data.

[0048] Furthermore, by analyzing the first thickness reduction data, the target current ratio that enables the film layer to achieve the required density can be determined. When the first thickness reduction data does not meet the set conditions, the intermediate current ratio corresponding to the first thickness reduction data does not meet the requirements. This intermediate current ratio can be determined as the new minimum current ratio or the new maximum current ratio to obtain a new current ratio range. The above steps are repeated to perform a binary search on the new current ratio range until the first thickness reduction data meets the set conditions. The intermediate current ratio corresponding to the first thickness reduction data meeting the set conditions can then be used as the target current ratio.

[0049] Based on this, this application provides a highly accurate current ratio adjustment method 100. According to the current ratio adjustment method 100 of this application, a suitable current ratio can be found by iteratively searching within the current ratio range using a bisection method with fewer adjustments. Moreover, the adjustment direction is clearly defined by whether the data of the first thickness reduction meets the set conditions, resulting in a highly accurate target current ratio.

[0050] In one example, the reduction in the first thickness can be calculated using various methods, such as the change in thickness of the first film before and after pickling, and the change between the total thickness of the wafer after the first film is deposited and the total thickness after pickling.

[0051] For example, after depositing a first film layer on a wafer at the middle current ratio in the current ratio range, the original thickness data of the deposited first film layer is obtained; then the wafer with the deposited first film layer is acid-washed, and the remaining thickness data of the first film layer after acid washing is obtained; then, the difference between the original thickness data and the remaining thickness data can be used to obtain the first thickness reduction data.

[0052] The original thickness data, remaining thickness data, original total thickness data, and remaining total thickness data can be obtained in various ways. For example, to obtain the original thickness data, after depositing the first film layer on the wafer at the middle current ratio within the current ratio range, the thickness of the first film layer can be measured at multiple points to obtain the original thickness data. Similarly, to obtain the remaining thickness data, after acid washing the wafer with the deposited first film layer, the remaining portion of the first film layer can be measured at the same multiple points used when obtaining the original thickness data to obtain the remaining thickness data.

[0053] It should be noted that the multiple points mentioned may or may not have a certain distribution pattern.

[0054] Taking the distribution pattern of multiple points as an example, the distribution pattern can be that the multiple points are distributed along the same diameter, or in a circular array, or in a rectangular array, or other distribution patterns, without limitation. For example, Figure 2 The diagram illustrates a method for thickness measurement using 49 points arranged in a circular array. Figure 3 The diagram shows a method for thickness measurement using 51 points, which are evenly distributed along the same diameter.

[0055] In one example, the setting condition could be that the difference between the first thickness reduction data and the set thickness reduction data is not greater than a set threshold.

[0056] Specifically, when the difference between the first thickness reduction data and the set thickness reduction data is greater than the set threshold, the first thickness reduction data does not meet the set conditions. At this time, the intermediate current ratio corresponding to the first thickness reduction data can be determined as the new minimum current ratio or the new maximum current ratio. When the difference between the first thickness reduction data and the set thickness reduction data is not greater than the set threshold, the first thickness reduction data meets the set conditions. At this time, the intermediate current ratio corresponding to the first thickness reduction data can be used as the target current ratio.

[0057] In one example, the setting condition could be that the color difference between the wafer test pattern generated based on the first thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is not greater than a color difference threshold.

[0058] Specifically, when the color difference between the wafer test pattern generated based on the first thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is greater than the color difference threshold, the first thickness reduction data does not meet the set conditions. In this case, the intermediate current ratio corresponding to the first thickness reduction data can be determined as the new minimum current ratio or the new maximum current ratio. When the color difference between the wafer test pattern generated based on the first thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is not greater than the color difference threshold, the first thickness reduction data meets the set conditions. In this case, the intermediate current ratio corresponding to the first thickness reduction data can be used as the target current ratio.

[0059] In one example, the set conditions may also include: the difference between the first thickness reduction data and the set thickness reduction data is not greater than a set threshold, and the color difference between the wafer test pattern generated based on the first thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is not greater than a color difference threshold.

[0060] Specifically, if the difference between the first thickness reduction data and the set thickness reduction data is greater than a set threshold, or if the color difference between the wafer test pattern generated based on the first thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is greater than a color difference threshold, the first thickness reduction data does not meet the set conditions. In this case, the intermediate current ratio corresponding to the first thickness reduction data can be determined as the new minimum current ratio or the new maximum current ratio. If the difference between the first thickness reduction data and the set thickness reduction data is not greater than a set threshold, and the color difference between the wafer test pattern generated based on the first thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is not greater than a color difference threshold, the first thickness reduction data meets the set conditions. In this case, the intermediate current ratio corresponding to the first thickness reduction data can be used as the target current ratio.

[0061] The thickness setting, threshold setting, and color difference threshold can be set according to the actual situation, and there are no restrictions on them.

[0062] Of course, this application does not exclude the possibility that the conditions may include other types of conditions, and does not limit this.

[0063] In one example, when the first thickness reduction data does not meet the set conditions, the thickness reduction trend of the film layer under the intermediate current ratio, the first end current ratio and the second end current ratio can be compared to determine whether the intermediate current ratio corresponding to the first thickness reduction data is a new minimum current ratio or a new maximum current ratio. There are many ways to compare the specific comparison process, and no limitation is imposed on it.

[0064] For example, second thickness reduction data and third thickness reduction data can be obtained first; wherein, the second thickness reduction data is the thickness reduction data of the second film layer after being acid-washed on a wafer with a second film layer deposited at the first end current ratio of the current ratio range; and the third thickness reduction data is the thickness reduction data of the third film layer after being acid-washed on a wafer with a third film layer deposited at the second end current ratio of the current ratio range.

[0065] Then, a first difference data can be obtained by subtracting the second thickness reduction data from the first thickness reduction data, and a second difference data can be obtained by subtracting the third thickness reduction data from the first thickness reduction data.

[0066] Then, the first difference data and the second difference data can be compared to determine whether the intermediate current ratio corresponding to the first thickness reduction data is the new minimum current ratio or the new maximum current ratio. For example, if the first difference data is greater than the second difference data, the intermediate current ratio can be determined to be the new minimum current ratio; if the first difference data is less than the second difference data, the intermediate current ratio can be determined to be the new maximum current ratio.

[0067] The specific process for obtaining the second and third thickness reduction data can refer to the specific process for obtaining the first thickness reduction data mentioned above, and is not limited thereto.

[0068] It should be noted that when the first, second, and third thickness reduction data include multiple point data, the difference and comparison can be performed on all point data, or only on the point data on the same diameter; there is no limitation on this.

[0069] For example, a first wafer test pattern, a second wafer test pattern, and a third wafer test pattern can also be determined first; wherein the first wafer test pattern is generated based on the first thickness reduction data, the second wafer test pattern is generated based on the second thickness reduction data, and the third wafer test pattern is generated based on the third thickness reduction data.

[0070] Then, the first color difference data between the second wafer test pattern and the first wafer test pattern can be determined, as well as the second color difference data between the third wafer test pattern and the first wafer test pattern.

[0071] Then, the first color difference data and the second color difference data can be compared to determine whether the intermediate current ratio corresponding to the first thickness reduction data is the new minimum current ratio or the new maximum current ratio. For example, if the first color difference data is less than the second color difference data, the intermediate current ratio is determined to be the new minimum current ratio; if the first color difference data is greater than the second color difference data, the intermediate current ratio is determined to be the new maximum current ratio.

[0072] It should be noted that the approximate first color difference between the second and first wafer test patterns, and the approximate second color difference between the third and first wafer test patterns, can be determined directly by visual inspection, and then the magnitudes of the first and second color difference data can be roughly compared by visual inspection. Alternatively, the precise first color difference between the second and first wafer test patterns, and the precise second color difference between the third and first wafer test patterns, can be determined by computer programs, and then the first and second color difference data can be accurately compared by computer programs.

[0073] For example, such as Figure 4 As shown, a first wafer test pattern is generated based on the first thickness reduction data corresponding to the middle current ratio of the initial current ratio range. In the attached figure, areas with larger grayscale values ​​represent larger thickness reduction values ​​of the first film layer, and areas with smaller grayscale values ​​represent smaller thickness reduction values ​​of the first film layer. Furthermore, Figure 5 It shows that Figure 4The corresponding intermediate current ratio is used as the new minimum current ratio or the new maximum current ratio. After determining the new current ratio range, the first wafer test pattern is generated based on the first thickness reduction data corresponding to the intermediate current ratio of the new current ratio range. It can be seen that compared to Figure 4 , Figure 5 The reduction in the thickness of the first film layer in the process is significantly decreased, that is, in Figure 5 The first film layer deposited under the corresponding adjusted intermediate current ratio, compared to that at... Figure 4 The density of the first film layer deposited under the intermediate current ratio before adjustment is significantly improved.

[0074] In one example, the current ratio adjustment method 100 can be applied to a variety of wafer deposition processes, such as chemical vapor deposition (CVD) and physical vapor deposition (PVD), without limitation.

[0075] For example, the current ratio adjustment method 100 can be preferably applied to sub-atmospheric chemical vapor deposition (SACVD).

[0076] Example 2

[0077] According to another aspect of this application, another method for adjusting the current ratio is also provided. For example... Figure 6 As shown, the current ratio adjustment method 200 applied to wafer deposition may include the following steps:

[0078] In step S210, a current ratio prediction model is established based on at least one set of wafer deposition data. Each set of wafer deposition data includes the current ratio and the wafer with a film deposited at that current ratio, as well as the data on the reduction in film thickness after acid washing.

[0079] In step S220, thickness reduction data that meets the set conditions is input into the current ratio prediction model, and the current ratio corresponding to the thickness reduction data output by the current ratio prediction model that meets the set conditions is taken as the target current ratio.

[0080] Specifically, one or more sets of wafer deposition data can be obtained in advance. Each set of wafer deposition data includes the current ratio and the wafer with the film deposited at that current ratio, as well as the reduction in film thickness after acid pickling. Since the density of the film and its resistance to acid pickling are positively correlated, the denser the film, the more resistant it is to acid corrosion, and the greater the remaining film thickness on the wafer; conversely, the more porous the film, the smaller the remaining film thickness on the wafer. Therefore, the density of the film can be reflected by the thickness reduction data.

[0081] Then, the relationship between the current ratio and thickness reduction data can be used to establish a current ratio prediction model. Subsequently, thickness reduction data meeting set conditions can be output to the current ratio prediction model, thereby predicting a suitable current ratio, i.e., the target current ratio.

[0082] Based on this, this application provides a highly accurate current ratio adjustment method 200. According to the current ratio adjustment method 200 of this application, by inputting thickness reduction data that meets the set conditions into the established current ratio prediction model, a suitable current ratio can be found with fewer adjustments. Moreover, by using whether the first thickness reduction data meets the set conditions as the adjustment direction, the adjustment direction is clear, and the target current ratio obtained by adjustment is highly accurate.

[0083] In one example, the current ratio in the at least one set of wafer deposition data can be obtained by performing a bisection on the current ratio interval, with the first endpoint of the current ratio interval being the minimum current ratio and the second endpoint being the maximum current ratio.

[0084] For example, at the beginning of the current ratio adjustment, there is a reasonable safe current ratio range, which can be used as the initial current ratio interval. Then, according to the idea of ​​the bisection method, iterative search is performed within the safe current ratio range to obtain one or more sets of wafer deposition data.

[0085] For example, one or more intermediate current ratios and one or more first thickness reduction data corresponding to one or more intermediate current ratios can be obtained by referring to the current ratio adjustment method 200 in Embodiment 1, and then a current ratio prediction model can be established based on one or more sets of data obtained.

[0086] In one example, the thickness reduction data can be calculated using various methods, such as the thickness change before and after film pickling, and the change between the total thickness of the wafer after film deposition and the total thickness after pickling.

[0087] For example, after depositing a film on a wafer at a corresponding current ratio, the original thickness data of the deposited film is obtained; then, the wafer with the deposited film is acid-washed, and the remaining thickness data of the film after acid washing is obtained; then, the difference between the original thickness data and the remaining thickness data is calculated to obtain the thickness reduction data.

[0088] The original thickness data, remaining thickness data, original total thickness data, and remaining total thickness data can be obtained in various ways. For example, to obtain the original thickness data, after depositing a film layer on the wafer at a corresponding current ratio, the film layer thickness can be measured at multiple points to obtain the original thickness data. Similarly, to obtain the remaining thickness data, after acid washing the wafer with the deposited film layer, the remaining film layer thickness can be measured at the same multiple points used when obtaining the original thickness data to obtain the remaining thickness data.

[0089] It should be noted that the multiple points mentioned may or may not have a certain distribution pattern.

[0090] Taking the distribution pattern of multiple points as an example, the distribution pattern can be that the multiple points are distributed along the same diameter, or in a circular array, or in a rectangular array, or other distribution patterns, without limitation. For example, Figure 2 The diagram illustrates a method for thickness measurement using 49 points arranged in a circular array. Figure 3 The diagram shows a method for thickness measurement using 51 points, which are evenly distributed along the same diameter.

[0091] In one example, after obtaining at least one set of wafer deposition data, a current ratio prediction model can be established according to the following procedure:

[0092] Since the power, sensitivity, etc. of different heating elements are not consistent, the influencing factors and response factors can be determined first. The influencing factors can include current ratio, pressure and temperature, and the response factors can include the thickness reduction data of the film layer after pickling.

[0093] In the example, the impact factor and the response factor can have the following functional relationship:

[0094] y = f(x1) + σ

[0095] E(y)=f(x1,x2=γ

[0096] Where y represents the response factor, x1 and x2 represent the influence factors, σ represents the detection error, E(y) represents the expectation of the response factor, and the surface represented by f(x1, x2) = γ is the response surface (RSM).

[0097] Next, the response surface (RSM) can be further determined and described using a second-order or higher-order model, as shown in the following expression:

[0098]

[0099] Where y represents the response factor, β represents the coefficient, x represents the influence factor, and ε represents the observation error;

[0100] Then, a quadratic curve model can be used for regression analysis. When considering the effects of pressure and temperature, the interaction relationship between the three influencing factors of current ratio, pressure, and temperature can also be obtained.

[0101] The following current ratio prediction model can then be formed:

[0102] Y1 = A + a*X1 + b*X2 + c*X3 + d*X1^2 + e*X2^2 + f*X3^2 + g*X1X2 + h*X1X3 + i*X2X3, simultaneously generating suitable Y2 and Y3, and calculating the quadratic surface response;

[0103] Subsequently, response surface analysis was performed on the current ratio prediction model, and digital optimization was carried out to obtain a suitable current ratio of 0.98, pressure of 300 mtorr, and temperature of 480℃.

[0104] After finding suitable current ratio, pressure, and temperature, further verification can be performed. The verification method can be based on the six sigma theory of current ratio, calculated according to the following formula:

[0105]

[0106] Where n is the total number of experiments, p is the number of terms in the model, and m is the number of experimental verifications.

[0107] In one example, n = 10, p = 8, m = 3, SE of Fits = 0.065, MSE in the ANOVA table is 0.01195, look up the t-quantile table t 1-α / 2 Given (np) = 2.447 and σ = 0.0023, the current ratio parameter is 0.98 ± 0.0023 when the confidence interval for the reduction in film thickness is 96%. If the target current ratio obtained from the current ratio prediction model falls within this range, the result is considered reliable; otherwise, the reliability is insufficient.

[0108] In one example, the setting condition could be that the difference between the thickness reduction data and the set thickness reduction data is not greater than a set threshold.

[0109] Specifically, when the difference between the thickness reduction data and the set thickness reduction data is greater than the set threshold, the thickness reduction data does not meet the set conditions; when the difference between the thickness reduction data and the set thickness reduction data is not greater than the set threshold, the thickness reduction data meets the set conditions.

[0110] In one example, the setting condition could be that the color difference between the wafer test pattern generated based on the thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is no greater than a color difference threshold.

[0111] Specifically, if the color difference between the wafer test pattern generated based on the thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is greater than the color difference threshold, the thickness reduction data does not meet the set conditions; if the color difference between the wafer test pattern generated based on the thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is not greater than the color difference threshold, the thickness reduction data meets the set conditions.

[0112] In one example, the set conditions may also include: the difference between the thickness reduction data and the set thickness reduction data is not greater than a set threshold, and the color difference between the wafer test pattern generated based on the thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is not greater than a color difference threshold.

[0113] Specifically, the thickness reduction data does not meet the set conditions when the difference between the thickness reduction data and the set thickness reduction data is greater than a set threshold, or when the color difference between the wafer test pattern generated based on the thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is greater than a color difference threshold; the thickness reduction data meets the set conditions when the difference between the thickness reduction data and the set thickness reduction data is not greater than a set threshold, and the color difference between the wafer test pattern generated based on the thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is not greater than a color difference threshold.

[0114] The thickness setting, threshold setting, and color difference threshold can be set according to the actual situation, and there are no restrictions on them.

[0115] Of course, this application does not exclude the possibility that the conditions may include other types of conditions, and does not limit this.

[0116] Example 3

[0117] According to another aspect of this application, a current ratio adjustment device is also provided. Figure 7A schematic block diagram of another current ratio adjustment device 300 according to an embodiment of this application is shown. Figure 3 As shown, the current ratio adjustment device 300 according to an embodiment of this application is applied to wafer deposition and may include a memory 310 and a processor 320. The memory 310 stores a computer program executed by the processor 320. When the computer program is executed by the processor 320, it causes the processor 320 to perform the current ratio adjustment method described above according to an embodiment of this application. Those skilled in the art can understand the specific operation of the current ratio adjustment device according to the embodiment of this application in conjunction with the foregoing description. For the sake of brevity, specific details will not be repeated here, and only some main operations of the processor 320 will be described.

[0118] In one embodiment of this application, when the computer program is run by the processor 320, the processor 320 performs the following steps: determining a current ratio range, wherein the first endpoint of the current ratio range is the minimum current ratio and the second endpoint is the maximum current ratio; acquiring first thickness reduction data, wherein the first thickness reduction data is the thickness reduction data of the first film layer after acid washing on a wafer with a first film layer deposited at the middle current ratio of the current ratio range; when the first thickness reduction data does not meet the set conditions, determining the middle current ratio as a new minimum current ratio or a new maximum current ratio; repeating the above steps until the first thickness reduction data meets the set conditions, and taking the middle current ratio corresponding to the first thickness reduction data meeting the set conditions as the target current ratio.

[0119] In one embodiment of this application, obtaining the first thickness reduction data includes: after depositing a first film layer on a wafer at a current ratio in the middle of the current ratio range, obtaining the original thickness data of the first film layer; after acid washing the wafer with the deposited first film layer, obtaining the remaining thickness data of the first film layer; and obtaining the first thickness reduction data by subtracting the original thickness data from the remaining thickness data.

[0120] In one embodiment of this application, obtaining the original thickness data of the first film layer includes: performing thickness detection on the first film layer at multiple points to obtain the original thickness data; obtaining the remaining thickness data of the first film layer includes: performing thickness detection on the remaining portion of the first film layer at multiple points to obtain the remaining thickness data.

[0121] In one embodiment of this application, the set conditions include: the difference between the first thickness reduction data and the set thickness reduction data is not greater than a set threshold; and / or the color difference between the wafer test pattern generated based on the first thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is not greater than a color difference threshold.

[0122] In one embodiment of this application, determining the intermediate current ratio as a new minimum current ratio or a new maximum current ratio includes: obtaining a first difference data by subtracting a second thickness reduction data from a first thickness reduction data; obtaining a second difference data by subtracting a third thickness reduction data from the first thickness reduction data; determining the intermediate current ratio as a new minimum current ratio when the first difference data is greater than the second difference data, or determining the intermediate current ratio as a new maximum current ratio when the first difference data is less than the second difference data; wherein, the second thickness reduction data is the thickness reduction data of the second film layer after acid washing on a wafer with a second film layer deposited at the first end current ratio of the current ratio range; the third thickness reduction data is the thickness reduction data of the third film layer after acid washing on a wafer with a third film layer deposited at the second end current ratio of the current ratio range.

[0123] In one embodiment of this application, determining the intermediate current ratio as a new minimum current ratio or a new maximum current ratio includes: determining a first color difference data between a second wafer test pattern and a first wafer test pattern; determining a second color difference data between a third wafer test pattern and a first wafer test pattern; determining the intermediate current ratio as a new minimum current ratio when the first color difference data is less than the second color difference data, or determining the intermediate current ratio as a new maximum current ratio when the first color difference data is greater than the second color difference data; wherein, the first wafer test pattern is generated based on first thickness reduction data; the second wafer test pattern is generated based on second thickness reduction data, the second thickness reduction data being the thickness reduction data of the second film layer after acid washing on a wafer with a second film layer deposited at the first endpoint current ratio of the current ratio range; the third wafer test pattern is generated based on third thickness reduction data, the third thickness reduction data being the thickness reduction data of the third film layer after acid washing on a wafer with a third film layer deposited at the second endpoint current ratio of the current ratio range.

[0124] In one embodiment of this application, the wafer deposition process is chemical vapor deposition.

[0125] Based on the above description, the current ratio adjustment device according to the embodiment of this application iteratively searches within the current ratio range using a binary search method, and can find a suitable current ratio with fewer adjustments. Moreover, by using whether the data of the first thickness reduction meets the set conditions as the adjustment direction, the adjustment direction is clear, and the accuracy of the target current ratio obtained by adjustment is high.

[0126] Example 4

[0127] According to another aspect of this application, another current ratio adjustment device is also provided. The current ratio adjustment device of this application embodiment is applied to wafer deposition and may include a memory and a processor. The memory stores a computer program executed by the processor. When the computer program is executed by the processor, it causes the processor to perform the current ratio adjustment method described above according to the embodiments of this application. Those skilled in the art can understand the specific operation of the current ratio adjustment device according to the embodiments of this application in conjunction with the foregoing description. For the sake of brevity, specific details are not repeated here, only some main operations of the processor are described.

[0128] In one embodiment of this application, when the computer program is run by the processor, the processor performs the following steps: establishing a current ratio prediction model based on at least one set of wafer deposition data, each set of wafer deposition data including the current ratio and the thickness reduction data of the wafer after pickling on a wafer with a film deposited at the current ratio; inputting the thickness reduction data that meets the set conditions into the current ratio prediction model, and using the current ratio corresponding to the thickness reduction data output by the current ratio prediction model that meets the set conditions as the target current ratio.

[0129] In one embodiment of this application, the current ratio in the at least one set of wafer deposition data can be obtained by performing a bisection on the current ratio interval, where the first endpoint of the current ratio interval is the minimum current ratio and the second endpoint is the maximum current ratio.

[0130] In one embodiment of this application, the process of obtaining thickness reduction data includes: after depositing a film layer on a wafer at a corresponding current ratio, obtaining the original thickness data of the deposited film layer; performing acid washing on the wafer with the film layer deposited, and obtaining the remaining thickness data of the film layer remaining after acid washing; and subtracting the original thickness data and the remaining thickness data to obtain the thickness reduction data.

[0131] In one embodiment of this application, obtaining the original thickness data of the film layer includes: performing thickness detection on the film layer at multiple points to obtain the original thickness data; obtaining the remaining thickness data of the film layer includes: performing thickness detection on the remaining portion of the film layer at multiple points to obtain the remaining thickness data.

[0132] In one embodiment of this application, the set conditions include: the difference between the thickness reduction data and the set thickness reduction data is not greater than a set threshold; and / or the color difference between the wafer test pattern generated based on the thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is not greater than a color difference threshold.

[0133] Based on the above description, the current ratio adjustment device according to the embodiment of this application can find a suitable current ratio with fewer adjustments by inputting thickness reduction data that meets the set conditions into the established current ratio prediction model. Moreover, the adjustment direction is clear by using whether the first thickness reduction data meets the set conditions, and the accuracy of the target current ratio obtained by adjustment is high.

[0134] Example 5

[0135] According to another aspect of this application, a wafer deposition apparatus is also provided. The wafer deposition apparatus includes a wafer heating element and a current ratio adjustment device. The wafer heating element includes an outer ring heating element and an inner ring heating element, with the inner ring heating element disposed inside the outer ring heating element. The current ratio adjustment device is used to adjust the current ratio between the outer ring heating element and the inner ring heating element.

[0136] The current ratio adjustment device can be implemented as the current ratio adjustment device described above, which can be referred to in the description above and will not be repeated here.

[0137] In one example, the deposition process of the wafer deposition equipment can be chemical vapor deposition, physical vapor deposition, etc., that is, the wafer deposition equipment can be a chemical vapor deposition device, a physical vapor deposition device, etc., without limitation.

[0138] For example, the wafer deposition equipment may preferably be a sub-atmospheric pressure chemical vapor deposition apparatus.

[0139] Based on the above description, the current ratio adjustment method and apparatus and wafer deposition equipment according to the embodiments of this application can find a suitable current ratio with fewer adjustments. Moreover, by using whether the first thickness reduction data meets the set conditions as the adjustment direction, the adjustment direction is clear and the accuracy of the target current ratio obtained by adjustment is high.

[0140] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0141] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0142] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed.

[0143] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0144] Similarly, it should be understood that, in order to streamline this application and aid in understanding one or more of the various inventive aspects, features of this application may sometimes be grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of this application. However, this approach should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the corresponding claims, its inventive point lies in solving the corresponding technical problem with features fewer than all features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0145] Those skilled in the art will understand that, apart from the mutual exclusion of features, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or apparatus so disclosed can be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0146] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0147] The various component embodiments of this application can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. Those skilled in the art will understand that microprocessors or digital signal processors (DSPs) can be used in practice to implement some or all of the functions of some modules according to the embodiments of this application. This application can also be implemented as an apparatus program (e.g., a computer program and computer program product) for performing part or all of the methods described herein. Such an implementation of this application can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0148] It should be noted that the above embodiments are illustrative of this application and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. This application can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names.

[0149] The above description is merely a specific embodiment or illustration of the embodiments of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. A current ratio adjustment method, characterized in that, The current ratio adjustment method is applied to adjust the current ratio between the outer heating element and the inner heating element in a wafer deposition equipment. The current ratio adjustment method includes: A current ratio range is defined, wherein the first endpoint of the current ratio range is the minimum current ratio, and the second endpoint is the maximum current ratio; Obtain first thickness reduction data, which is the thickness reduction data of the first film layer after acid washing of a wafer with a first film layer deposited at the middle current ratio of the current ratio range. When the first thickness reduction data does not meet the set conditions, the intermediate current ratio is determined to be a new minimum current ratio or a new maximum current ratio; wherein, the set conditions include: the difference between the first thickness reduction data and the set thickness reduction data is not greater than a set threshold; and / or the color difference between the wafer test pattern generated based on the first thickness reduction data and the wafer test pattern generated based on the set thickness reduction data is not greater than a color difference threshold; Repeat the above steps until the first thickness reduction data meets the set conditions, and take the intermediate current ratio corresponding to the first thickness reduction data meeting the set conditions as the target current ratio.

2. The current ratio adjustment method as described in claim 1, characterized in that, The acquisition of the first thickness reduction data includes: After depositing the first film layer on the wafer at the middle current ratio within the current ratio range, the original thickness data of the first film layer is obtained. After acid washing the wafer on which the first film layer is deposited, the remaining thickness data of the first film layer is obtained. The first thickness reduction data is obtained by subtracting the original thickness data from the remaining thickness data.

3. The current ratio adjustment method as described in claim 2, characterized in that, The step of obtaining the original thickness data of the first film layer includes: performing thickness detection on the first film layer at multiple points to obtain the original thickness data; The step of obtaining the remaining thickness data of the first film layer includes: performing thickness detection on the remaining portion of the first film layer at the multiple points to obtain the remaining thickness data.

4. The current ratio adjustment method as described in claim 1, characterized in that, Determining the intermediate current ratio as a new minimum current ratio or a new maximum current ratio includes: The first difference data is obtained by subtracting the second thickness reduction data from the first thickness reduction data. The second difference data is obtained by subtracting the third thickness reduction data from the first thickness reduction data; When the first difference data is greater than the second difference data, the intermediate current ratio is determined to be the new minimum current ratio; or, when the first difference data is less than the second difference data, the intermediate current ratio is determined to be the new maximum current ratio. Wherein, the second thickness reduction data is the thickness reduction data of the second film layer after being acid-washed on a wafer with a second film layer deposited at the first end current ratio of the current ratio range; the third thickness reduction data is the thickness reduction data of the third film layer after being acid-washed on a wafer with a third film layer deposited at the second end current ratio of the current ratio range.

5. The current ratio adjustment method as described in claim 1, characterized in that, Determining the intermediate current ratio as a new minimum current ratio or a new maximum current ratio includes: Determine the first color difference data between the second wafer test pattern and the first wafer test pattern; Determine the second color difference data between the third wafer test pattern and the first wafer test pattern; When the first color difference data is less than the second color difference data, the intermediate current ratio is determined as the new minimum current ratio; or, when the first color difference data is greater than the second color difference data, the intermediate current ratio is determined as the new maximum current ratio. The first wafer test pattern is generated based on the first thickness reduction data; the second wafer test pattern is generated based on the second thickness reduction data, which is the thickness reduction data of the second film layer after acid washing on a wafer with a second film layer deposited at the first end current ratio of the current ratio range; the third wafer test pattern is generated based on the third thickness reduction data, which is the thickness reduction data of the third film layer after acid washing on a wafer with a third film layer deposited at the second end current ratio of the current ratio range.

6. The current ratio adjustment method according to any one of claims 1 to 5, characterized in that, The wafer deposition process is chemical vapor deposition.

7. A current ratio adjustment device, characterized in that, The current ratio adjustment device is applied to wafer deposition. The current ratio adjustment device includes a memory and a processor. The memory stores a computer program executed by the processor. The computer program, when executed by the processor, causes the processor to perform the current ratio adjustment method as described in any one of claims 1 to 6.

8. A wafer deposition apparatus, characterized in that, The wafer deposition equipment includes a wafer heating element and a current ratio adjustment device as described in claim 7. The wafer heating element includes an outer ring heating element and an inner ring heating element. The inner ring heating element is disposed inside the outer ring heating element. The current ratio adjustment device is used to adjust the current ratio between the outer ring heating element and the inner ring heating element.

9. The wafer deposition apparatus as described in claim 8, characterized in that, The wafer deposition equipment is a chemical vapor deposition apparatus.

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