A method, apparatus and device for improving wafer lithography quality
By obtaining the focal length energy matrix and linear relationship, calculating the energy error range, and allocating appropriate lithography equipment for etching, the energy error problem caused by prolonged use of the lithography equipment lamp was solved, thereby improving the uniformity of wafer etching line width and the lithography quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHANGXIN MEMORY TECH INC
- Filing Date
- 2022-05-06
- Publication Date
- 2026-06-12
AI Technical Summary
The existing lamp illumination method of lithography equipment leads to uneven wafer etching line width. This is mainly due to the accumulation of dirt on the electrodes after prolonged use of the lamps, as well as the reduction in lamp brightness and changes in light intensity, which cause energy errors.
By obtaining the focal length energy matrix of the wafer to be etched, the linewidth window, reference exposure energy and reference focal length of the target pattern are determined. The linear relationship between exposure energy and etching linewidth is fitted, the energy error range is calculated, and a matching lithography machine is assigned for etching. The lithography quality is monitored and adjusted in real time.
It effectively reduces the non-uniformity of wafer etching line width, improves photolithography quality, extends lamp life, and ensures the stability of the etching process through real-time monitoring and adjustment.
Smart Images
Figure CN114839840B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor technology, specifically to a method, apparatus, and equipment for improving wafer lithography quality. Background Technology
[0002] Currently, the lighting method for semiconductor lithography machines typically uses lamp illumination, such as... Figure 1 As shown, the high-voltage discharge at the positive and negative electrodes excites the liquid Hg inside the lamp into an unstable gaseous Hg*. The Hg* combines with stable gases (Br2, F2, etc.) to produce light of a specific wavelength.
[0003] The above-mentioned lithography machine's lamp illumination method has the following two defects, such as... Figure 2 As shown:
[0004] 1) Due to the accumulation of dirt on the electrodes after prolonged use, the brightness of the lamp will gradually decrease over time.
[0005] 2) The lamp uses high-voltage electrodes to induce electron transitions to achieve illumination. The light intensity produced by this method is subject to slight changes in real time depending on the strength of the current and the amount of excited ions.
[0006] The aforementioned defects can cause energy errors in the actual output energy (Dose) of the lamp, resulting in uneven width of the etched lines on the wafer. Summary of the Invention
[0007] This disclosure provides a method, apparatus, and equipment for improving wafer lithography quality, solving the problem of uneven width of etching lines on wafers caused by energy errors due to actual output energy in current lithography machine lamp illumination methods.
[0008] In a first aspect, this disclosure provides a method for improving wafer lithography quality, the method comprising:
[0009] Obtain the focal length energy matrix of the layer to be etched on the wafer;
[0010] Based on the focal length energy matrix, the linewidth window, reference exposure energy, and reference focal length of the target pattern of the layer to be etched are obtained; the linewidth window is the linewidth error window allowed for the target pattern when it meets the quality requirements, the reference exposure energy is the optimal exposure energy corresponding to the target pattern when it meets the quality requirements, and the reference focal length is the optimal exposure focal length corresponding to the target pattern when it meets the quality requirements.
[0011] Under the optimal exposure focal length condition, a linear relationship between exposure energy and etching linewidth is fitted. Based on the linewidth window, the reference exposure energy, and the slope corresponding to the linear relationship, the energy error range of the target pattern is obtained.
[0012] Based on the energy error range, a lithography machine that matches the energy error range is assigned to etch the layer to be etched.
[0013] In one possible implementation, the energy error range of the target image is obtained based on the linewidth window, the reference exposure energy, and the slope corresponding to the linear relationship, including:
[0014] Calculate the product of the reference exposure energy and the slope;
[0015] The energy error range of the target graphic is obtained by calculating the ratio of the line width window to the product.
[0016] In one possible implementation, obtaining the reference exposure energy and the reference focal length includes:
[0017] The focal length and energy matrix corresponding to the layer to be etched are obtained by changing the exposure focal length and exposure energy respectively. The focal length and energy matrix includes multiple sets of exposure data, and each set of exposure data includes exposure energy, exposure focal length and etching linewidth.
[0018] Under the premise that the exposure focal length remains unchanged, determine the set of exposure data with the smallest difference between the etching linewidth and the standard linewidth of the target pattern, and determine the exposure energy in the set of exposure data as the reference exposure energy;
[0019] Under the premise of constant exposure energy, determine the set of exposure data with the smallest difference between the etching linewidth and the standard linewidth of the target pattern, and determine the exposure focal length in the set of exposure data as the reference focal length.
[0020] In one possible implementation, the fitting of the linear relationship between exposure energy and etching linewidth includes:
[0021] Acquire multiple sets of exposure data at the reference focal length;
[0022] The exposure energy in the multiple sets of exposure data is used as the horizontal axis data, and the etching linewidth in the multiple sets of exposure data is used as the vertical axis data to obtain multiple discrete data points on the coordinate axis.
[0023] The slope of the linear relationship is obtained by fitting a linear relationship to the multiple discrete data points.
[0024] In one possible implementation, according to the determined energy error range, assigning a lithography stage matching the energy error range to etch the layer to be etched includes:
[0025] The energy error ranges corresponding to the multiple layers to be etched are sorted according to their size, and the multiple lithography machines to be allocated are sorted according to the exposure quality determined by the exposure performance.
[0026] A lithography machine with a first exposure quality etches the layer to be etched within a first energy error range, and a lithography machine with a second exposure quality etches the layer to be etched within a second energy error range, wherein the first exposure quality is higher than the second exposure quality, and the first energy error range is greater than the second energy error range.
[0027] In one possible implementation, determining the exposure quality of the plurality of lithography stations includes:
[0028] Establish a pre-established relationship between the light intensity of the exposure light source and its usage time. Based on the current usage time of the exposure light source of the lithography machine, determine the light intensity of the current exposure light source of the lithography machine.
[0029] The exposure quality of the current lithography machine is determined based on the light intensity.
[0030] In one possible implementation, after obtaining the energy error range of the target pattern, the method further includes:
[0031] Determine two endpoints corresponding to the energy error range, and multiply the two endpoints by a preset percentage to obtain the corrected energy error range, wherein the preset percentage is a value less than 1;
[0032] Based on the corrected energy error range, the photolithography quality of the layer to be etched is monitored online in real time.
[0033] In one possible implementation, the method further includes: when the target pattern includes multiple etching linewidths, determining the smallest energy error range among the energy error ranges corresponding to the multiple etching linewidths as the energy error range of the target pattern of the layer to be etched.
[0034] Secondly, this disclosure provides an apparatus for improving wafer lithography quality, the apparatus comprising:
[0035] An acquisition module is used to acquire the focal length energy matrix of the layer to be etched on the wafer; and based on the focal length energy matrix, acquire the linewidth window, reference exposure energy, and reference focal length of the target pattern of the layer to be etched; the linewidth window is the allowable linewidth error window of the target pattern when meeting quality requirements, the reference exposure energy is the optimal exposure energy corresponding to the target pattern when meeting quality requirements, and the reference focal length is the optimal exposure focal length corresponding to the target pattern when meeting quality requirements;
[0036] The fitting module is used to fit a linear relationship between exposure energy and etching linewidth under the optimal exposure focal length condition.
[0037] The calculation module obtains the energy error range of the target image based on the linewidth window, the reference exposure energy, and the slope corresponding to the linear relationship.
[0038] The control module is used to allocate a lithography machine that matches the energy error range to etch the layer to be etched, based on the energy error range.
[0039] In one possible implementation, the acquisition module obtains multiple sets of exposure data by changing the exposure focal length and exposure energy respectively. Each set of exposure data includes exposure energy, exposure focal length and etching linewidth. Based on the multiple sets of exposure data, a focal length-energy matrix corresponding to the layer to be etched is constructed.
[0040] In one possible implementation, the calculation module calculates the product of the reference exposure energy and the slope, and calculates the ratio of the linewidth window to the product, to obtain the energy error range of the target image.
[0041] In one possible implementation, the apparatus further includes a storage module for pre-recording the current lithography quality of the plurality of lithography stations; the control module allocates the plurality of lithography stations based on the energy error range and the lithography quality.
[0042] In one possible implementation, the device further includes a monitoring module, which is used to multiply the energy error range by a preset percentage to obtain a corrected energy error range, wherein the preset percentage is a value less than 1; and to monitor the photolithography quality of the layer to be etched based on the corrected energy error range.
[0043] Thirdly, this disclosure provides a system for improving wafer lithography quality, the system comprising:
[0044] At least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform any of the methods described in the first aspect above.
[0045] Fourthly, this disclosure provides a computer storage medium storing a computer program for causing a computer to perform any of the methods described in the first aspect above.
[0046] This disclosure provides a method, apparatus, and equipment for improving wafer lithography quality. By calculating the energy error range corresponding to the layer to be etched based on the focal length energy matrix of the layer to be etched, and allocating a lithography machine that matches the corresponding energy error range to the layer to be etched, this solves the problems of current lithography machine lighting methods. For example, the brightness of the lamp gradually decreases over time due to the accumulation of dirt on the electrodes. Furthermore, the light intensity generated by the lamp using high-voltage electrodes to induce electron transitions is subject to slight changes in the current strength and the number of excited ions, which leads to energy errors in the actual output energy of the lamp and results in uneven width of the etched lines on the wafer. Attached Figure Description
[0047] Figure 1 This is a schematic diagram illustrating the basic principle of a lithography machine lamp according to an embodiment of a method for improving wafer lithography quality disclosed herein;
[0048] Figure 2 This is a schematic diagram illustrating the error generated by a lithography machine according to an embodiment of a method for improving wafer lithography quality disclosed herein;
[0049] Figure 3 This is a schematic flowchart of an embodiment of a method for improving wafer lithography quality according to the present disclosure;
[0050] Figure 4 This is a schematic diagram of the focal length energy matrix according to an embodiment of a method for improving wafer lithography quality according to the present disclosure;
[0051] Figure 5 This is a schematic diagram of the brightness of the mercury lamp on a lithography machine according to an embodiment of a method for improving wafer lithography quality according to this disclosure;
[0052] Figure 6 This is a schematic diagram of monitoring lithography quality according to an embodiment of a method for improving wafer lithography quality according to the present disclosure;
[0053] Figure 7 This is a schematic diagram of monitoring energy error according to an embodiment of a method for improving wafer lithography quality according to the present disclosure;
[0054] Figure 8 This is a schematic diagram of the monitoring etching line width according to an embodiment of a method for improving wafer lithography quality according to the present disclosure;
[0055] Figure 9 This is a schematic diagram illustrating the specific process of allocating a lithography machine according to an embodiment of a method for improving wafer lithography quality disclosed herein;
[0056] Figure 10 This is a schematic diagram of an embodiment of an apparatus for improving wafer lithography quality according to the present disclosure;
[0057] Figure 11 This is a schematic diagram of an embodiment of a method for improving wafer lithography quality according to the present disclosure. Detailed Implementation
[0058] The technical solutions in the embodiments of this disclosure will now be described clearly and in detail with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.
[0059] To address the problem of low wafer lithography quality caused by the lighting methods of existing lithography machines, embodiments of this disclosure provide a method for improving wafer lithography quality, such as... Figure 3 As shown, the method includes:
[0060] S301: Obtain the focal length energy matrix of the layer to be etched on the wafer.
[0061] like Figure 4 The diagram shows the focal energy matrices for etched layers A and B. Focal energy matrices are a testing method used to check the lithography process window and determine optimal exposure conditions. By using different exposure focal lengths and energies in different areas of a silicon wafer, different combinations of process conditions can be generated. This method allows for experimentation on a silicon wafer to determine the allowable range of focus depth and exposure, as well as the optimal focal length and optimal exposure energy. Different etched layers correspond to different focal energy matrices. In the diagram, the first row represents the focal length, the first column represents the exposure energy, and the data in the other rows and columns represent the etch linewidths corresponding to different focal lengths and exposure energies.
[0062] S302: Based on the focal length energy matrix, obtain the linewidth window, reference exposure energy, and reference focal length of the target pattern of the layer to be etched; the linewidth window is the linewidth error window allowed for the target pattern when meeting quality requirements, the reference exposure energy is the optimal exposure energy corresponding to the target pattern when meeting quality requirements, and the reference focal length is the optimal exposure focal length corresponding to the target pattern when meeting quality requirements.
[0063] The width of the linewidth window of the target pattern of the layer to be etched is preset. The reference focal length and reference exposure energy are queried from the focal length energy matrix according to the standard linewidth of the target pattern. During the query process, it is found that there are multiple target patterns in the focal length energy matrix, and there may not be any size that is exactly the same as the standard linewidth of the target pattern. At this time, a linewidth window can be set, and the linewidth window within the error range can be selected.
[0064] S303: Under the optimal exposure focal length condition, a linear relationship between exposure energy and etching linewidth is fitted, and the energy error range of the target pattern is obtained based on the linewidth window, the reference exposure energy, and the slope corresponding to the linear relationship.
[0065] In one possible implementation, the fitting of the linear relationship between exposure energy and etching linewidth includes:
[0066] Multiple sets of exposure data are acquired at the reference focal length, wherein the multiple sets of exposure data are multiple etching linewidths and corresponding multiple exposure energies corresponding to the reference focal length. Specifically, this can be achieved by... Figure 4 As shown, taking the focal length energy matrix of the B etching layer as an example, 0.2 is the reference focal length (optimal exposure focal length), and the column containing the reference focal length contains multiple etching linewidths, with each etching corresponding to an exposure energy.
[0067] The exposure energy in the multiple sets of exposure data is used as the horizontal axis data, and the etching linewidth in the multiple sets of exposure data is used as the vertical axis data to obtain multiple discrete data points on the coordinate axis.
[0068] By fitting a linear relationship to the multiple discrete data points, we obtain, as follows: Figure 4 The slope of the linear relationship can be obtained from the equation of the line shown.
[0069] If the target pattern includes multiple etching linewidths, the smallest energy error range among the energy error ranges corresponding to the multiple etching linewidths shall be determined as the energy error range of the target pattern of the layer to be etched.
[0070] S304: Based on the energy error range, assign a lithography machine that matches the energy error range to etch the layer to be etched.
[0071] Different lithography machines produce different exposure qualities, which can be determined using the following methods:
[0072] Establish a pre-established relationship between the light intensity of the exposure light source and its usage time. Based on the current usage time of the exposure light source of the lithography machine, determine the light intensity of the current exposure light source of the lithography machine.
[0073] The exposure quality of the current lithography machine is determined based on the light intensity.
[0074] like Figure 5 As shown, the brightness maintenance rate of the mercury lamp in a lithography machine decreases with increasing lamp-on time. Consequently, the exposure quality of the lithography machine also decreases. Real-time monitoring of the mercury lamp's brightness reflects its illumination performance, thus guiding lamp replacement.
[0075] This disclosure provides a method for improving wafer lithography quality by calculating the energy error range corresponding to the layer to be etched on the wafer, and allocating a lithography machine of corresponding quality to the layer to be etched according to the energy error range. This method can control the products on the production line and improve the lithography quality of the wafer.
[0076] The acquisition of the reference focal length and reference exposure energy in S302 above can be specifically implemented through the following methods:
[0077] Obtaining the reference exposure energy and the reference focal length includes:
[0078] The focal length and energy matrix corresponding to the layer to be etched are obtained by changing the exposure focal length and exposure energy respectively. The focal length and energy matrix includes multiple sets of exposure data, and each set of exposure data includes exposure energy, exposure focal length and etching linewidth.
[0079] Under the premise that the exposure focal length remains unchanged, determine the set of exposure data with the smallest difference between the etching linewidth and the standard linewidth of the target pattern, and determine the exposure energy in the set of exposure data as the reference exposure energy;
[0080] Under the premise of constant exposure energy, determine the set of exposure data with the smallest difference between the etching linewidth and the standard linewidth of the target pattern, and determine the exposure focal length in the set of exposure data as the reference focal length.
[0081] As shown in Table 1, the standard linewidth of etching layer A is 730 nanometers, and the linewidth window is 25 nanometers. That is to say, the linewidth error range allowed for the target pattern of etching layer A to meet the quality requirements is 25 nanometers. In other words, the etching linewidth of the target pattern can meet the quality requirements if it is between 705 nanometers and 755 nanometers.
[0082] like Figure 4As shown, taking etching layer A as an example, the focal length at the center of the matrix can be selected as the reference focal length. Under the condition that the reference exposure focal length is 0.3, the etching linewidth with the smallest difference between this column of the focal length energy matrix and the standard linewidth of the target pattern is 737.66 nanometers. Within the aforementioned etching linewidth range, the reference exposure energy is therefore 125 mJ / cm². 2 ).
[0083] Table 1
[0084] Etching layer A B Standard line width 730nm 730nm Line width window ±25nm ±30nm Reference Exposure Energy <![CDATA[125(mj / cm 2 )]]> <![CDATA[140(mj / cm 2 )]]> slope 3.75 2.15 Energy error range ±5％ ±10％
[0085] In step S303 above, after determining the slope of the linear relationship, the energy error range of the target graphic is calculated, which can be specifically implemented through the following method:
[0086] In one possible implementation, the energy error range of the target image is obtained based on the linewidth window, the reference exposure energy, and the slope corresponding to the linear relationship, including:
[0087] Calculate the product of the reference exposure energy and the slope;
[0088] The energy error range of the target graphic is obtained by calculating the ratio of the line width window to the product.
[0089] Taking the data in Table 1 as an example, the linewidth window of the B etching layer is 30 nanometers, corresponding to a slope of 2.15 for the linear relationship, and the reference exposure energy is 140 mJ / cm². 2 According to the formula: Energy error range = line width window / (reference exposure energy × slope), 30 / (140 × 2.15) is calculated to give an energy error range of approximately 10%.
[0090] However, before etching, a monitoring standard needs to be set to facilitate monitoring of the etching process. Two endpoints corresponding to the energy error range are determined, and each endpoint is multiplied by a preset percentage to obtain the corrected energy error range. The preset percentage is a value less than 1. Based on the corrected energy error range, the lithography quality of the layer to be etched is monitored online in real time. For example, if the energy error range of etched layer A is ±5%, meaning the exposure energy during the lithography process is within this range, the etching linewidth of etched layer A can meet the quality requirements. However, in actual operation, to facilitate control of online products, a monitoring standard (such as ±4%) needs to be set. When the exposure energy error range of the lithography machine reaches ±4%, the system will issue an alarm, allowing staff to take timely corresponding measures, such as adjusting the current of the lithography machine to adjust the exposure energy.
[0091] The specific monitoring process is as follows: Figure 6 As shown:
[0092] S601: Real-time monitoring of energy error during the etching process;
[0093] S602: Obtain the pre-calculated energy error range corresponding to each etched layer stored in the system;
[0094] S603: Determine whether the monitored energy error exceeds the monitoring standard. If it does not exceed the standard, proceed to S604; otherwise, proceed to S605.
[0095] S604: Maintain the current working status of the lithography machine;
[0096] S605: Issue a warning;
[0097] S606: Staff shall take appropriate measures based on the actual situation.
[0098] Figure 7 This diagram illustrates real-time monitoring of energy error. The circled areas represent situations where the energy error exceeds the monitoring standard. Figure 8 This is a schematic diagram of another method for monitoring energy errors. By monitoring the width of the etching linewidth during the photolithography process, it can be determined whether the exposure energy of the photolithography machine exceeds the monitoring standard. Figure 8 The data within the middle circle indicates that the etching linewidth is too small, which may result in insufficient exposure energy.
[0099] The etching of the layer to be etched by allocating a lithography machine that matches the energy error range in S304 above can be specifically implemented through the following methods:
[0100] In one possible implementation, according to the determined energy error range, assigning a lithography stage matching the energy error range to etch the layer to be etched includes:
[0101] The energy error ranges corresponding to the multiple layers to be etched are sorted according to their size, and the multiple lithography machines to be allocated are sorted according to the exposure quality determined by the exposure performance.
[0102] A lithography machine with a first exposure quality etches the layer to be etched within a first energy error range, and a lithography machine with a second exposure quality etches the layer to be etched within a second energy error range, wherein the first exposure quality is higher than the second exposure quality, and the first energy error range is greater than the second energy error range.
[0103] To reduce the energy error range of the etched layer, which has a large range of quantity error, the energy is allocated to a lithography machine with high exposure quality. This ensures the etching quality and extends the lifespan of the mercury lamp.
[0104] The specific allocation process is as follows: Figure 9 As shown:
[0105] S901: Obtain the exposure quality of the lithography machine;
[0106] S902: Calculate and record the energy error range of the etched layer;
[0107] S903: Through data analysis by the real-time dispatch system, sort the energy error ranges of different etching layers, determine the size of their energy error ranges, and count the usage time of the mercury lamp on the lithography machine. If the energy error range is large, execute S904; if the energy error range is small, execute S905; if the usage time of the mercury lamp exceeds the preset range, execute S906.
[0108] S904: Assign a high-quality lithography machine for etching;
[0109] S905: Assign a lower-quality lithography machine for etching;
[0110] S906: Replaces the mercury lamp for the lithography machine.
[0111] Based on the same inventive concept, this disclosure also provides an apparatus 1000 for improving wafer lithography quality, such as... Figure 10 As shown, the device includes:
[0112] The acquisition module 1001 is used to acquire the focal length energy matrix of the layer to be etched on the wafer; and based on the focal length energy matrix, acquire the linewidth window, reference exposure energy, and reference focal length of the target pattern of the layer to be etched; the linewidth window is the allowable linewidth error window of the target pattern when meeting quality requirements, the reference exposure energy is the optimal exposure energy corresponding to the target pattern when meeting quality requirements, and the reference focal length is the optimal exposure focal length corresponding to the target pattern when meeting quality requirements;
[0113] The fitting module 1002 is used to fit a linear relationship between exposure energy and etching linewidth under the optimal exposure focal length condition.
[0114] The calculation module 1003 obtains the energy error range of the target image based on the linewidth window, the reference exposure energy, and the slope corresponding to the linear relationship.
[0115] The control module 1004 is used to allocate a lithography machine that matches the energy error range to etch the layer to be etched, based on the energy error range.
[0116] In one possible implementation, the acquisition module 1001 obtains multiple sets of exposure data by changing the exposure focal length and exposure energy respectively. Each set of exposure data includes exposure energy, exposure focal length and etching linewidth. Based on the multiple sets of exposure data, a focal length-energy matrix corresponding to the layer to be etched is constructed.
[0117] In one possible implementation, the calculation module 1003 calculates the product of the reference exposure energy and the slope, and calculates the ratio of the linewidth window to the product, to obtain the energy error range of the target image.
[0118] In one possible implementation, the apparatus further includes a storage module for pre-recording the current lithography quality of the plurality of lithography stations; the control module allocates the plurality of lithography stations based on the energy error range and the lithography quality.
[0119] In one possible implementation, the device further includes a monitoring module, which is used to multiply the energy error range by a preset percentage to obtain a corrected energy error range, wherein the preset percentage is a value less than 1; and to monitor the photolithography quality of the layer to be etched based on the corrected energy error range.
[0120] In one possible implementation, the acquisition module 1001 is further configured to acquire multiple sets of exposure data at the reference focal length; and use the exposure energy in the acquired multiple sets of exposure data as the horizontal axis data, and the etching linewidth in the acquired multiple sets of exposure data as the vertical axis data, to obtain multiple discrete data points located on the coordinate axis; and obtain the slope of the linear relationship by fitting a linear relationship through the multiple discrete data points.
[0121] In one possible implementation, the sorting module is used to sort the energy error ranges corresponding to the multiple layers to be etched according to the size of the range, and to sort the multiple lithography machines to be allocated according to the exposure quality determined by the exposure performance.
[0122] A lithography machine with a first exposure quality etches the layer to be etched within a first energy error range, and a lithography machine with a second exposure quality etches the layer to be etched within a second energy error range, wherein the first exposure quality is higher than the second exposure quality, and the first energy error range is greater than the second energy error range.
[0123] In one possible implementation, the determining module is further configured to determine the light intensity of the current lithography machine's exposure light source based on the usage time of the current exposure light source, according to a pre-established correspondence between the light intensity and usage time of the exposure light source.
[0124] The exposure quality of the current lithography machine is determined based on the light intensity.
[0125] In one possible implementation, the determining module is further configured to, when the target pattern includes multiple etching linewidths, determine the smallest energy error range among the energy error ranges corresponding to the multiple etching linewidths as the energy error range of the target pattern of the layer to be etched.
[0126] Based on the same inventive concept, this disclosure also provides a system for improving wafer lithography quality, the system comprising:
[0127] At least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform any of the methods described above for improving wafer lithography quality.
[0128] The following reference Figure 11 To describe an electronic device 130 according to such an embodiment of the present disclosure. Figure 11 The electronic device 130 shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments disclosed herein.
[0129] like Figure 11 As shown, the electronic device 130 is presented in the form of a general-purpose electronic device. The components of the electronic device 130 may include, but are not limited to: at least one processor 131, at least one memory 132, and a bus 133 connecting different system components (including memory 132 and processor 131).
[0130] The processor 131 is configured to read instructions from the memory 132 and execute them, so that the at least one processor can perform:
[0131] Obtain the focal length energy matrix of the layer to be etched on the wafer;
[0132] Based on the focal length energy matrix, the linewidth window, reference exposure energy, and reference focal length of the target pattern of the layer to be etched are obtained; the linewidth window is the linewidth error window allowed for the target pattern when it meets the quality requirements, the reference exposure energy is the optimal exposure energy corresponding to the target pattern when it meets the quality requirements, and the reference focal length is the optimal exposure focal length corresponding to the target pattern when it meets the quality requirements.
[0133] Under the optimal exposure focal length condition, a linear relationship between exposure energy and etching linewidth is fitted. Based on the linewidth window, the reference exposure energy, and the slope corresponding to the linear relationship, the energy error range of the target pattern is obtained.
[0134] Based on the energy error range, a lithography machine that matches the energy error range is assigned to etch the layer to be etched.
[0135] In one possible implementation, the processor 131 obtains the energy error range of the target image based on the linewidth window, the reference exposure energy, and the slope corresponding to the linear relationship, including:
[0136] Calculate the product of the reference exposure energy and the slope;
[0137] The energy error range of the target graphic is obtained by calculating the ratio of the line width window to the product.
[0138] In one possible implementation, the processor 131 acquires the reference exposure energy and the reference focal length, including:
[0139] The focal length and energy matrix corresponding to the layer to be etched are obtained by changing the exposure focal length and exposure energy respectively. The focal length and energy matrix includes multiple sets of exposure data, and each set of exposure data includes exposure energy, exposure focal length and etching linewidth.
[0140] Under the premise that the exposure focal length remains unchanged, determine the set of exposure data with the smallest difference between the etching linewidth and the standard linewidth of the target pattern, and determine the exposure energy in the set of exposure data as the reference exposure energy;
[0141] Under the premise of constant exposure energy, determine the set of exposure data with the smallest difference between the etching linewidth and the standard linewidth of the target pattern, and determine the exposure focal length in the set of exposure data as the reference focal length.
[0142] In one possible implementation, the processor 131 acquires multiple sets of exposure data at the reference focal length;
[0143] The exposure energy in the multiple sets of exposure data is used as the horizontal axis data, and the etching linewidth in the multiple sets of exposure data is used as the vertical axis data to obtain multiple discrete data points on the coordinate axis.
[0144] The slope of the linear relationship is obtained by fitting a linear relationship to the multiple discrete data points.
[0145] In one possible implementation, the processor 131 allocates a lithography stage matching the determined energy error range to etch the layer to be etched, including:
[0146] The energy error ranges corresponding to the multiple layers to be etched are sorted according to their size, and the multiple lithography machines to be allocated are sorted according to the exposure quality determined by the exposure performance.
[0147] A lithography machine with a first exposure quality etches the layer to be etched within a first energy error range, and a lithography machine with a second exposure quality etches the layer to be etched within a second energy error range, wherein the first exposure quality is higher than the second exposure quality, and the first energy error range is greater than the second energy error range.
[0148] In one possible implementation, the processor 131 determines the exposure quality of the plurality of lithography stations by including:
[0149] Establish a pre-established relationship between the light intensity of the exposure light source and its usage time. Based on the current usage time of the exposure light source of the lithography machine, determine the light intensity of the current exposure light source of the lithography machine.
[0150] The exposure quality of the current lithography machine is determined based on the light intensity.
[0151] In one possible implementation, after the processor 131 obtains the energy error range of the target pattern, it further includes:
[0152] Determine two endpoints corresponding to the energy error range, and multiply the two endpoints by a preset percentage to obtain the corrected energy error range, wherein the preset percentage is a value less than 1;
[0153] Based on the corrected energy error range, the photolithography quality of the layer to be etched is monitored online in real time.
[0154] In one possible implementation, when the target pattern includes multiple etching linewidths, the processor 131 determines the smallest energy error range among the energy error ranges corresponding to the multiple etching linewidths as the energy error range of the target pattern of the layer to be etched.
[0155] Bus 133 represents one or more of several bus structures, including a memory bus or memory controller, peripheral bus, processor, or local bus using any of the various bus structures.
[0156] The memory 132 may include a readable medium in the form of volatile memory, such as random access memory (RAM) 1321 and / or cache memory 1322, and may further include read-only memory (ROM) 1323.
[0157] The memory 132 may also include a program / utility 1325 having a set (at least one) of program modules 1324, including but not limited to: an operating system, one or more application programs, other program modules, and program data, each or some combination of these examples may include an implementation of a network environment.
[0158] Electronic device 130 can also communicate with one or more external devices 134 (e.g., keyboard, pointing device, etc.), and with one or more devices that enable a user to interact with electronic device 130, and / or with any device that enables electronic device 130 to communicate with one or more other electronic devices (e.g., router, modem, etc.). This communication can be performed via input / output (I / O) interface 135. Furthermore, electronic device 130 can also communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), and / or public networks, such as the Internet) via network adapter 136. As shown, network adapter 136 communicates with other modules used in electronic device 130 via bus 133. It should be understood that, although not shown in the figures, other hardware and / or software modules can be used in conjunction with electronic device 130, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID systems, tape drives, and data backup storage systems.
[0159] In some possible implementations, various aspects of a method for improving wafer lithography quality provided in this disclosure can also be implemented in the form of a program product comprising program code that, when run on a computer device, causes the computer device to perform the steps of a method for improving wafer lithography quality according to various exemplary embodiments of this disclosure as described above.
[0160] In addition, this disclosure also provides a computer-readable storage medium storing a computer program for causing a computer to perform the method described in any of the above embodiments.
[0161] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.
[0162] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.
[0163] Although preferred embodiments of this disclosure have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this disclosure.
[0164] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.
Claims
1. A method for improving wafer lithography quality, characterized in that, The method includes: Obtain the focal length energy matrix of the layer to be etched on the wafer; Based on the focal length energy matrix, the linewidth window, reference exposure energy, and reference focal length of the target pattern of the layer to be etched are obtained; the linewidth window is the linewidth error window allowed for the target pattern when it meets the quality requirements, the reference exposure energy is the optimal exposure energy corresponding to the target pattern when it meets the quality requirements, and the reference focal length is the optimal exposure focal length corresponding to the target pattern when it meets the quality requirements. Under the optimal exposure focal length condition, a linear relationship between exposure energy and etching linewidth is fitted. Based on the linewidth window, the reference exposure energy, and the slope corresponding to the linear relationship, the energy error range of the target pattern is obtained. Based on the energy error range, a lithography machine that matches the energy error range is assigned to etch the layer to be etched. After obtaining the energy error range of the target pattern, the method further includes: Determine two endpoints corresponding to the energy error range, and multiply the two endpoints by a preset percentage to obtain the corrected energy error range, wherein the preset percentage is a value less than 1; Based on the corrected energy error range, the photolithography quality of the layer to be etched is monitored online in real time.
2. The method according to claim 1, characterized in that, Based on the linewidth window, the reference exposure energy, and the slope corresponding to the linear relationship, the energy error range of the target image is obtained, including: Calculate the product of the reference exposure energy and the slope; The energy error range of the target graphic is obtained by calculating the ratio of the line width window to the product.
3. The method according to claim 1, characterized in that, Obtaining the reference exposure energy and the reference focal length includes: The focal length and energy matrix corresponding to the layer to be etched are obtained by changing the exposure focal length and exposure energy respectively. The focal length and energy matrix includes multiple sets of exposure data, and each set of exposure data includes exposure energy, exposure focal length and etching linewidth. Under the premise that the exposure focal length remains unchanged, determine the set of exposure data with the smallest difference between the etching linewidth and the standard linewidth of the target pattern, and determine the exposure energy in the set of exposure data as the reference exposure energy; Under the premise of constant exposure energy, determine the set of exposure data with the smallest difference between the etching linewidth and the standard linewidth of the target pattern, and determine the exposure focal length in the set of exposure data as the reference focal length.
4. The method according to claim 3, characterized in that, The linear relationship between exposure energy and etching linewidth obtained by fitting includes: Acquire multiple sets of exposure data at the reference focal length; The exposure energy in the multiple sets of exposure data is used as the horizontal axis data, and the etching linewidth in the multiple sets of exposure data is used as the vertical axis data to obtain multiple discrete data points on the coordinate axis. The slope of the linear relationship is obtained by fitting a linear relationship to the multiple discrete data points.
5. The method according to claim 1, characterized in that, Based on the determined energy error range, an etchable layer is etched using a lithography machine that matches the energy error range, including: The energy error ranges corresponding to the multiple layers to be etched are sorted according to their size, and the multiple lithography machines to be allocated are sorted according to the exposure quality determined by the exposure performance. A lithography machine with a first exposure quality etches the layer to be etched within a first energy error range, and a lithography machine with a second exposure quality etches the layer to be etched within a second energy error range, wherein the first exposure quality is higher than the second exposure quality, and the first energy error range is greater than the second energy error range.
6. The method according to claim 5, characterized in that, Determining the exposure quality of multiple lithography machines includes: Establish a pre-established relationship between the light intensity of the exposure light source and its usage time. Based on the current usage time of the exposure light source of the lithography machine, determine the light intensity of the current exposure light source of the lithography machine. The exposure quality of the current lithography machine is determined based on the light intensity.
7. The method according to claim 1, characterized in that, Also includes: When the target pattern includes multiple etching linewidths, the smallest energy error range among the energy error ranges corresponding to the multiple etching linewidths is determined as the energy error range of the target pattern of the layer to be etched.
8. An apparatus for improving wafer lithography quality, characterized in that, The device includes: An acquisition module is used to acquire the focal length energy matrix of the layer to be etched on the wafer; and based on the focal length energy matrix, acquire the linewidth window, reference exposure energy, and reference focal length of the target pattern of the layer to be etched; the linewidth window is the allowable linewidth error window of the target pattern when meeting quality requirements, the reference exposure energy is the optimal exposure energy corresponding to the target pattern when meeting quality requirements, and the reference focal length is the optimal exposure focal length corresponding to the target pattern when meeting quality requirements; The fitting module is used to fit a linear relationship between exposure energy and etching linewidth under the optimal exposure focal length condition. The calculation module obtains the energy error range of the target image based on the linewidth window, the reference exposure energy, and the slope corresponding to the linear relationship. The control module is used to allocate a lithography machine that matches the energy error range to etch the layer to be etched, based on the energy error range. The monitoring module is used to multiply the energy error range by a preset percentage to obtain a corrected energy error range, wherein the preset percentage is a value less than 1; and to monitor the photolithography quality of the layer to be etched based on the corrected energy error range.
9. The apparatus for improving wafer lithography quality according to claim 8, characterized in that, The acquisition module obtains multiple sets of exposure data by changing the exposure focal length and exposure energy respectively. Each set of exposure data includes exposure energy, exposure focal length and etching linewidth. Based on the multiple sets of exposure data, a focal length-energy matrix corresponding to the layer to be etched is constructed.
10. The apparatus for improving wafer lithography quality according to claim 8, characterized in that, The calculation module calculates the product of the reference exposure energy and the slope, and calculates the ratio of the linewidth window to the product, to obtain the energy error range of the target image.
11. The apparatus for improving wafer lithography quality according to claim 8, characterized in that, The device further includes a storage module for pre-recording the current lithography quality of multiple lithography stations; the control module allocates multiple lithography stations based on the energy error range and the lithography quality.
12. A system for improving wafer lithography quality, characterized in that, The system includes: At least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method as described in any one of claims 1-7.
13. A computer storage medium, characterized in that, The computer storage medium stores a computer program that enables the computer to perform the method as described in any one of claims 1-7.