An exposure dose control method based on an exposure dose control system

Abstract

The application provides an exposure dose control method based on an exposure dose control system, which comprises the following steps: controlling a shutter to open; receiving an energy value collected by an energy sensor, determining an accumulated exposure dose value based on the energy value; determining whether the accumulated exposure dose value is not less than a target dose value; if the accumulated exposure dose value is not less than the target dose value, controlling the shutter to start to close; taking the accumulated exposure dose value corresponding to a shake delay end moment after the shutter is completely closed as an actual accumulated exposure dose value; determining an exposure dose error value based on the actual accumulated exposure dose value; determining whether the exposure dose error value meets a requirement; if the exposure dose error value does not meet the requirement, updating an equivalent dose value and returning to execute the first step; if the exposure dose error value meets the requirement, applying the equivalent dose value to an exposure system. Through the exposure dose control method based on the exposure dose control system, the problem of low exposure dose control precision is solved.

Description

Technical Field

[0001] This application relates to the field of photolithography technology, and more specifically, to an exposure dose control method based on an exposure dose control system. Background Technology

[0002] Photolithography is a crucial process in semiconductor manufacturing. The photolithography process generally involves silicon wafer pretreatment, resist coating, pre-baking, exposure, development, post-baking, etching, resist removal, and overlay. It is a relatively complex process, with each step influencing and constraining the others. Exposure is a critical step affecting product quality; it involves using a specific wavelength and intensity of light to irradiate the photoresist through a mask, causing a photochemical reaction in the irradiated area. After development, the resulting image corresponds to the pattern on the mask.

[0003] Exposure dose is the product of light intensity and exposure time, used to represent the exposure energy obtained on the photoresist surface. Since a certain exposure dose is required to produce a good pattern on the photoresist, if the exposure time is too short, the exposure dose is below the threshold and development is not possible. If the exposure time is too long, the exposure dose is above the threshold, the photoresist's resistance to etching decreases, jagged edges appear on the edges of the pattern after development, and wrinkles appear on the surface of the photoresist film, affecting the exposure quality. Therefore, exposure dose is a key parameter affecting exposure quality.

[0004] Currently, the common method for controlling exposure dose is open-loop control, which directly controls the exposure dose by adjusting the light intensity, resulting in low accuracy in exposure dose control. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide an exposure dose control method, device, electronic device and storage medium based on an exposure dose control system, so as to solve the problem of low exposure dose control accuracy.

[0006] In a first aspect, embodiments of this application provide an exposure dose control method based on an exposure dose control system, the exposure dose control system including a light source, a shutter, an attenuator, a lens group unit, a beam splitter, and an energy sensor;

[0007] The exposure dose control methods include:

[0008] (A) Receives a light source turn-on command and controls the light source to turn on;

[0009] (B) Receive the shutter opening command to control the shutter to open so that the light emitted by the light source passes through the shutter, attenuator, lens group unit and beam splitter in sequence and then shines on the energy sensor;

[0010] (C) Receive the energy value collected by the energy sensor, and determine the cumulative exposure dose value based on the energy value. The cumulative exposure dose value is used to characterize the exposure dose that accumulates over time from the start time. The start time refers to the moment when the energy sensor collects the energy value of the light.

[0011] (D) Determine whether the cumulative exposure dose value is not less than the target dose value. The target dose value is determined by the equivalent dose value. The equivalent dose value is the equivalent value of the exposure dose generated during the shutter closing process and the shake delay process. The shutter closing process is the process from the beginning of shutter closing to complete closing. The shake delay process is the process of light leakage caused by shutter motor shaking after the shutter is completely closed.

[0012] (E) If the cumulative exposure dose value is not less than the target dose value, then control the shutter to start closing;

[0013] (F) The cumulative exposure dose value corresponding to the end time of the shake delay after the shutter is fully closed is taken as the actual cumulative exposure dose value. The end time of the shake delay is the time after the set time has elapsed since the shutter is fully closed.

[0014] (G) Determine the exposure dose error value based on the actual cumulative exposure dose value;

[0015] (H) Determine whether the exposure dose error value meets the requirements;

[0016] (I) If the exposure dose error value does not meet the requirements, update the equivalent dose value and return to step (B);

[0017] (J) If the exposure dose error value meets the requirements, the equivalent dose value will be applied to the exposure system to expose the silicon wafer.

[0018] Optionally, step (C) includes: (C1) acquiring the energy value of the energy sensor in the absence of light; and (C2) determining the cumulative exposure dose value based on the energy value in the absence of light and the energy value of light.

[0019] Optionally, step (C2) includes: determining the difference between the energy value of the light and the energy value under no light as the target energy value; determining the objective function based on the target energy value and the conversion factor; and determining the cumulative exposure dose value by integrating the objective function over the time interval.

[0020] Optionally, step (G) includes: determining the absolute value of the difference between the set dose value and the actual cumulative exposure dose value as the dose difference; and determining the ratio of the dose difference to the set dose value as the exposure dose error value.

[0021] Optionally, step (H) includes: determining whether the exposure dose error value is less than the dose fluctuation threshold; if the exposure dose error value is less than the dose fluctuation threshold, then determining that the exposure dose error value meets the requirements; if the exposure dose error value is greater than or equal to the dose fluctuation threshold, then determining that the exposure dose error value does not meet the requirements.

[0022] Optionally, step (I) includes: if the exposure dose error value does not meet the requirements, determining whether the actual cumulative exposure dose value is greater than the set dose value; if the actual cumulative exposure dose value is greater than the set dose value, increasing the equivalent time and updating the equivalent dose value using the increased equivalent time; if the actual cumulative exposure dose value is less than the set dose value, decreasing the equivalent time and updating the equivalent dose value using the decreased equivalent time.

[0023] Optionally, the method further includes: selecting a target attenuation range corresponding to a set dose value, wherein the target attenuation range is an attenuation range selected from multiple candidate attenuation ranges; determining the attenuation amplitude of the attenuator based on the target attenuation range; and controlling the attenuator to attenuate the energy value of the light emitted by the light source by the attenuation amplitude.

[0024] Secondly, embodiments of this application also provide an exposure dose control system, the system comprising: a control unit, a light source, a shutter, an attenuator, a lens group unit, a beam splitter, and an energy sensor;

[0025] The control unit receives a command to turn on the light source and controls the light source to turn on.

[0026] The control unit receives the shutter opening command and controls the shutter to open so that the light emitted by the light source passes through the shutter, attenuator, lens group unit and beam splitter in sequence before shining on the energy sensor;

[0027] The energy sensor collects the energy value of the light and sends the collected energy value to the control unit;

[0028] The control unit receives the energy value sent by the energy sensor and determines the cumulative exposure dose value based on the energy value. The cumulative exposure dose value is used to characterize the exposure dose that accumulates over time from the start time. The start time refers to the moment when the energy sensor collects the energy value of the light.

[0029] The control unit determines whether the cumulative exposure dose value is not less than the target dose value. If it determines that the cumulative exposure dose value is not less than the target dose value, it controls the shutter to start closing. The target dose value is determined by the equivalent dose value, which is the equivalent value of the exposure dose generated during the shutter closing process and the shake delay process. The shutter closing process is the process from the start of closing the shutter to the complete closing of the shutter. The shake delay process is the process of light leakage caused by the shutter motor shaking after the shutter is completely closed.

[0030] The control unit determines the exposure dose error value based on the actual cumulative exposure dose value, which is the cumulative exposure dose value corresponding to the end of the shake delay after the shutter is completely closed;

[0031] The control unit determines whether the exposure dose error value meets the requirements. If the exposure dose error value does not meet the requirements, it updates the equivalent dose value and uses the updated equivalent dose value to determine the exposure dose error value that meets the requirements. If the exposure dose error value meets the requirements, it applies the equivalent dose value to the exposure system to expose the silicon wafer.

[0032] Thirdly, embodiments of this application also provide an electronic device, including: a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. When the machine-readable instructions are executed by the processor, the steps of the exposure dose control method based on the exposure dose control system described above are performed.

[0033] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the exposure dose control method based on the exposure dose control system described above.

[0034] The embodiments of this application bring the following beneficial effects:

[0035] This application provides an exposure dose control method based on an exposure dose control system, which can adjust the shutter closing time by adjusting the equivalent dose value, determine a more suitable shutter closing time point, and ensure that the difference between the actual exposure dose value and the set dose value is within a specified range, thereby improving the accuracy of the exposure dose. Compared with the exposure dose control methods in the prior art, it solves the problem of low exposure dose control accuracy.

[0036] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 A flowchart of the exposure dose control method provided in an embodiment of this application is shown;

[0039] Figure 2 A schematic diagram of the sampling data of the energy sensor provided in the embodiments of this application is shown;

[0040] Figure 3 A schematic diagram illustrating the relationship between exposure dose and time provided in the embodiments of this application is shown;

[0041] Figure 4 A schematic diagram illustrating the relationship between light intensity value and time provided in the embodiments of this application is shown;

[0042] Figure 5 A flowchart of the shutter control method provided in an embodiment of this application is shown;

[0043] Figure 6 This illustration shows a schematic diagram of the dose repeatability of a set dose provided in an embodiment of this application;

[0044] Figure 7 This illustration shows a schematic diagram of the dose repeatability of the set dose two provided in the embodiments of this application;

[0045] Figure 8 A schematic diagram of the exposure dose control system provided in an embodiment of this application is shown;

[0046] Figure 9 A schematic diagram of the structure of the electronic device provided in the embodiments of this application is shown. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. Based on the embodiments of this application, every other embodiment obtained by those skilled in the art without inventive effort falls within the scope of protection of this application.

[0048] It is worth noting that prior to this application, photolithography was a crucial process in semiconductor manufacturing. The photolithography process generally involves silicon wafer pretreatment, resist coating, pre-baking, exposure, development, post-baking, etching, resist removal, and overlay, making it a complex process where each step influences and restricts the others. Exposure is a critical step affecting product quality; it involves using a specific wavelength and intensity of light to irradiate the photoresist through a mask, causing a photochemical reaction in the irradiated area. After development, a pattern corresponding to the mask is obtained. Exposure dose is the product of light intensity and exposure time, representing the exposure energy received by the photoresist surface. A certain exposure dose is required to produce a good pattern on the photoresist. If the exposure time is too short, the exposure dose is below a threshold, and development is impossible. If the exposure time is too long, the exposure dose exceeds the threshold, reducing the photoresist's resistance to etching, resulting in jagged edges on the pattern after development and wrinkles on the photoresist surface, thus affecting exposure quality. Therefore, exposure dose is a key parameter affecting exposure quality. Currently, the common method for controlling exposure dose is open-loop control, which directly controls the exposure dose by adjusting the light intensity, resulting in low accuracy in exposure dose control.

[0049] Based on this, embodiments of this application provide an exposure dose control method based on an exposure dose control system to improve the control accuracy of exposure dose.

[0050] Please see Figure 1 , Figure 1 This is a flowchart illustrating an exposure dose control method based on an exposure dose control system, provided as an embodiment of this application. Figure 1 As shown in the embodiment of this application, the exposure dose control method based on the exposure dose control system includes a light source, shutter, attenuator, lens group unit, beam splitter, and energy sensor.

[0051] Here, the exposure dose control system can refer to an experimental system used to determine the equivalent time. After the equivalent time is determined by the system, it is applied to the exposure system. The exposure system also controls the shutter to start closing when the cumulative exposure dose value is equal to the target dose value. Therefore, the equivalent time determined by the exposure dose control method can achieve precise control of the exposure dose.

[0052] It should be noted that the exposure dose control system also includes a control unit. The exposure dose control method is applied to the control unit to control the exposure dose.

[0053] The exposure dose control methods include:

[0054] Step S100: Receive a light source turn-on command and control the light source to turn on.

[0055] In this step, the light source can refer to a device capable of emitting light of a specified wavelength. For example, the light source can be an LED light source or a mercury lamp light source.

[0056] In this embodiment, the control unit of the exposure dose control system receives a light source turn-on command and controls the light source to turn on. Here, the wavelength of the light emitted by the light source can be 365nm, or it can be other wavelengths, which can be selected by those skilled in the art according to the actual situation.

[0057] Step S110: Receive a shutter opening command and control the shutter to open so that the light emitted by the light source passes through the shutter, attenuator, lens group unit, and beam splitter in sequence before illuminating the energy sensor.

[0058] In this step, the shutter can refer to a device that controls the duration of light exposure. The shutter is used to control the length of the exposure time. For example, the shutter is located below the light source in the exposure dose control system so that the light emitted by the light source can pass through the shutter.

[0059] An attenuator is a component that reduces the intensity of light. Attenuators are used to adjust the intensity of light. For example, an attenuator is located below the shutter in an exposure dose control system to adjust the attenuation of light passing through the shutter.

[0060] The lens unit may refer to a light-diffusing lens unit, which is used to distribute light evenly. For example, the lens unit is located below the attenuator in the exposure dose control system to adjust the distribution of light passing through the attenuator.

[0061] A beam splitter can refer to a beam splitter. A beam splitter is used to split an incident beam into two beams, one transmitted and one reflected, with a certain intensity ratio. For example, the beam splitter is located below the lens group unit in the exposure dose control system to perform beam splitting processing on the beam passing through the lens group unit.

[0062] An energy sensor is used to collect the energy value of light. For example, the energy sensor is located below the beam splitter in the exposure dose control system to collect the energy value of the light passing through the beam splitter. The energy sensor has a sampling frequency of 10 kHz, meaning it samples once every 0.1 milliseconds.

[0063] Step S120: Receive the energy value collected by the energy sensor and determine the cumulative exposure dose value based on the energy value.

[0064] In this step, the energy value of the light collected by the energy sensor is a binary bit value, denoted as ESbit. Then, the collected energy value is converted into a light intensity value.

[0065] The following reference Figure 2 Let's introduce the sampling data from the energy sensor.

[0066] Figure 2 A schematic diagram of the sampling data of the energy sensor provided in the embodiments of this application is shown.

[0067] like Figure 2 As shown, the horizontal axis represents time, in units of 0.1 ms (milliseconds), and the vertical axis represents light intensity, in units of mW (milliwatts). Throughout the exposure process, both the shutter opening and closing processes are gradual.

[0068] The cumulative exposure dose value refers to the cumulative value of the exposure dose over a period of time. The cumulative exposure dose value is used to characterize the exposure dose that accumulates over time from the beginning.

[0069] The start time refers to the moment when the energy sensor collects the energy value of the light.

[0070] In an optional embodiment, step S120 includes: acquiring the energy value of the energy sensor under no light; and determining the cumulative exposure dose value based on the energy value under no light and the energy value of light.

[0071] Here, the energy value under no-light conditions refers to the dark current value of the energy sensor, also known as the no-light current, denoted as ESbit (offset). The dark current value refers to the current flowing in the light-receiving element of the device in the absence of light. The dark current value is a current unrelated to the photocurrent; it is the reverse DC current generated by the device under reverse bias conditions when there is no incident light.

[0072] In the embodiments of this application, the cumulative exposure dose value can be determined based on the dark current value of the energy sensor and the energy value of the light illuminating the energy sensor.

[0073] In an optional embodiment, the step of determining the cumulative exposure dose value based on the energy value under no light and the energy value of light includes: determining the difference between the energy value of light and the energy value under no light as the target energy value; determining the objective function based on the target energy value and the conversion factor; and determining the cumulative exposure dose value by integrating the objective function over the time interval.

[0074] Here, the conversion factor can refer to the scaling factor that converts the energy value collected by the energy sensor into the light intensity value. The conversion factor is used to convert the energy value into the light intensity value and is denoted as ESCF.

[0075] The conversion factor is a fixed value calibrated by the light intensity meter. For example, the conversion factor can be a floating-point number, such as 0.1.

[0076] The following reference Figure 3 This section will introduce the relationship between dose and time.

[0077] Figure 3 A schematic diagram illustrating the relationship between exposure dose and time provided in the embodiments of this application is shown.

[0078] like Figure 3 As shown, the horizontal axis represents time, and the vertical axis represents exposure dose. E1 is the desired exposure dose value, T0 is the start time of exposure, and T1 is the end time of exposure. It can be seen that, over time, with a constant light intensity, the exposure dose value has a linear relationship with time. The angle α is related to the light intensity value; the greater the light intensity, the larger the angle α.

[0079] Based on the above relationship between exposure dose and time, the cumulative exposure dose value can be calculated using the following formula:

[0080]

[0081] Where E represents the cumulative exposure dose value, I represents the light intensity value, t represents the time, ESCF represents the conversion factor, ESbit represents the energy value collected by the energy sensor, and ESbit_offset represents the energy value of the energy sensor in the absence of light.

[0082] The objective function is ESCF×(ESbit-ESbit_offset)×t, where ESbit-ESbit_offset is the target energy value.

[0083] The cumulative exposure dose value from the start time to the current time can be calculated using the formula above.

[0084] Step S130: Determine whether the cumulative exposure dose value is not less than the target dose value.

[0085] In this step, the target dose value can refer to the dose value that is expected to be achieved before the shutter begins to close. The target dose value is used to adjust the time when the shutter begins to close.

[0086] The target dose value is determined by the equivalent dose value, which is equal to the difference between the set dose value and the equivalent dose value.

[0087] The equivalent dose value is the equivalent exposure dose generated during the shutter closing process and the shake delay process, denoted as Eequal. Specifically, the exposure dose generated during the shutter closing process refers to the exposure dose generated from the start of shutter closure to complete closure, while the exposure dose generated during the shake delay process refers to the exposure dose generated when light leaks due to shutter motor shake.

[0088] The magnitude of the equivalent dose value is determined by the equivalent time, which is equal to the product of the equivalent time and the equivalent light intensity.

[0089] The equivalent time can refer to a set time, which is used to represent the time of the shutter closing process and the shake delay process, and is denoted as Tequal. Those skilled in the art can select the initial equivalent time according to the actual situation, and this application does not limit it.

[0090] Equivalent light intensity refers to the light intensity value used to calculate the equivalent dose value, denoted as Iequal. Equivalent light intensity can be obtained through calculation. In the embodiments of this application, after the light emitted by the light source stabilizes, multiple light intensity values ​​can be obtained, and the average of these multiple light intensity values ​​can be used as the equivalent light intensity. For example, 100 light intensity values ​​can be obtained, and the average of these 100 light intensity values ​​can be used as the equivalent light intensity.

[0091] The set dose value refers to the total exposure dose value that is expected to be achieved, denoted as Eset.

[0092] It should be noted that the shutter closing process is the process from the beginning of the shutter closing to the complete closing, while the shake delay process is the process of light leakage caused by the shutter motor shaking after the shutter is completely closed.

[0093] Step S140: If the cumulative exposure dose value is not less than the target dose value, then control the shutter to start closing.

[0094] In this step, since the target dose value is equal to the difference between the set dose value and the equivalent dose value, and the equivalent dose value is used to characterize the dose value generated during the shutter closing process and the shake delay process, the target dose value also characterizes the exposure dose value expected to be achieved between the start of energy value acquisition from the energy sensor and the start of shutter closing.

[0095] The following reference Figure 4 Let's introduce the relationship between light intensity and time.

[0096] Figure 4 A schematic diagram illustrating the relationship between light intensity value and time provided in the embodiments of this application is shown.

[0097] like Figure 4As shown, the horizontal axis represents time, and the vertical axis represents light intensity. t0 is the moment the shutter begins to open, t1 is the moment the shutter is fully open, t2 is the moment the shutter begins to close, t3 is the moment the shutter is fully closed, and t4 is the moment the camera shake ends. Iequal is the equivalent light intensity. Since the exposure dose value is linearly related to time when the light intensity is constant, the entire shaded area in the figure represents the exposure dose value between t0 and t4. The shaded area between t0 and t1 represents the exposure dose value generated during the shutter opening process, the shaded area between t2 and t3 represents the exposure dose value generated during the shutter closing process, and the shaded area between t3 and t4 represents the exposure dose value generated during the camera shake delay process. If E3 represents the exposure dose value between t2 and t3, and E4 represents the exposure dose value between t3 and t4, then E3 + E4 is the exposure dose value after the shutter begins to close. This exposure dose value after the shutter begins to close includes the exposure dose value generated during the shutter closing process and the exposure dose value generated during the camera shake delay process.

[0098] As is understandable, the equivalent dose value is the exposure dose value after the shutter begins to close, corresponding to E3+E4. At the same time, the result of subtracting the equivalent dose value from the set dose value is the exposure dose value generated before the shutter begins to close, which is the target dose value. If the cumulative exposure dose value is equal to the target dose value, it means that the shutter should start to close at this moment.

[0099] Step S150: The cumulative exposure dose value corresponding to the end time of the shake delay after the shutter is fully closed is taken as the actual cumulative exposure dose value. The end time of the shake delay is the time after a set duration is elapsed from the moment the shutter is fully closed.

[0100] In this step, the actual cumulative exposure dose value can refer to the exposure dose value from the start time to the end time of the jitter delay, in order to... Figure 4 For example, the exposure dose value corresponding to the black area between t0 and t4.

[0101] The actual cumulative exposure dose value is compared with the set dose value to determine the difference between the actual exposure dose value and the expected set dose value.

[0102] It should be noted that the shutter has multiple states, including open, open, closing, and closed. The exposure completion flag is set based on the shutter state to determine the actual cumulative exposure dose value. The initial value of the exposure completion flag is false. The shutter state is acquired in real time when calculating the actual cumulative exposure dose value, and the decision to continue accumulating the exposure dose value is determined based on the shutter state.

[0103] The following reference Figure 5 This section will explain the calculation process for the actual cumulative exposure dose value.

[0104] Figure 5 A flowchart of the shutter control method provided in an embodiment of this application is shown.

[0105] like Figure 5 As shown, after executing step S110, step S151 also needs to be executed.

[0106] Step S151: Set the shutter status to open.

[0107] Here, since the exposure is complete, it needs to be adjusted after the shutter is opened because the current shutter state is required to determine whether the exposure is complete.

[0108] Step S152: Determine whether the exposure completion marker is false.

[0109] Here, the exposure completion marker can refer to a 0 or 1 number. The exposure completion marker is used to determine whether the exposure process has ended.

[0110] If the exposure completion marker is marked as false, proceed to step S153; otherwise, end the exposure process.

[0111] Step S153: Determine the cumulative exposure dose value based on the energy value.

[0112] Here, since the exposure completion is marked as non-true, it means that the exposure dose value still needs to be accumulated. Therefore, the cumulative exposure dose value is calculated by integration.

[0113] Step S154: Determine the shutter status.

[0114] Here, the shutter state is obtained, and corresponding processing is performed based on the obtained current shutter state. If the shutter state is determined to be open, step S1541 is executed; if the shutter state is determined to be open, step S1544 is executed; if the shutter state is determined to be closed, step S1545 is executed; if the shutter state is determined to be closed, step S1547 is executed.

[0115] Step S1541: Determine if the shutter has stopped.

[0116] Here, if the shutter state is determined to be open, the degree of shutter opening can be determined by whether the shutter has stopped moving. If the shutter has stopped moving, it means the shutter is fully open, and step S1542 is executed. If the shutter has not stopped moving, it means the shutter is not fully open, and step S152 is returned to be executed.

[0117] Step S1542: Set the shutter status to open.

[0118] Here, after confirming that the shutter is fully open, the shutter state needs to be adjusted. Therefore, the shutter state can be set to open, and then step S1543 can be executed.

[0119] Step S1543: Calculate the target dose value.

[0120] Here, since the shutter is fully open, the time point at which the shutter begins to close can be determined. Because this time point is determined by comparing the cumulative exposure dose value with the target dose value, the target dose value needs to be calculated first. After obtaining the target dose value, return to step S152.

[0121] Step S1544: If the cumulative exposure dose value is not less than the target dose value, control the shutter to start closing and set the shutter status to closed.

[0122] Here, if the cumulative exposure dose value is not less than the target dose value, it means that the shutter needs to be closed and the shutter status needs to be adjusted to be closed. Then, return to step S152.

[0123] Step S1545: Determine if the shutter has stopped.

[0124] Here, if the shutter state is determined to be closed, the completeness of the shutter closure can be determined by whether the shutter has stopped moving. If the shutter has stopped moving, it means the shutter is closed, and step S1546 is executed. If the shutter has not stopped moving, it means the shutter is not closed, and the process returns to step S152. It should be noted that "the shutter is closed" does not include the shake delay process; "the shutter is closed" signifies the end of the shutter closing process.

[0125] Step S1546: Set the shutter status to closed.

[0126] Here, since it has been confirmed that the shutter is closed, the shutter status needs to be adjusted.

[0127] Step S1547: Set the exposure complete flag to true.

[0128] Here, if the shutter status is determined to be closed, it means that the shutter closing process is over, and the exposure complete flag needs to be set to true so that the cumulative exposure dose value generated during the shake delay process can be accumulated from this moment.

[0129] Specifically, after setting the exposure complete flag to true and confirming that the exposure complete flag is true, the shake delay timer starts, and the cumulative exposure dose value when the shutter state is closed continues to be integrated. When the shake delay time reaches the shake delay threshold, it is the shake delay end time after the shutter is completely closed, and the integration of the cumulative exposure dose value ends. The cumulative exposure dose value at this time is taken as the actual cumulative exposure dose value.

[0130] Step S160: Determine the exposure dose error value based on the actual cumulative exposure dose value.

[0131] In this step, the exposure dose error value can refer to the value calculated based on the actual cumulative exposure dose value. The exposure dose error value is used to characterize the difference between the actual exposure dose value and the set dose value during the entire exposure process, reflecting the control accuracy of the exposure dose.

[0132] The larger the exposure dose error value, the greater the difference between the actual exposure dose value and the set dose value, and the lower the control accuracy of the exposure dose.

[0133] In an optional embodiment, step S160 includes: determining the absolute value of the difference between the set dose value and the actual cumulative exposure dose value as the dose difference; and determining the ratio of the dose difference to the set dose value as the exposure dose error value.

[0134] Here, the exposure dose error value is determined by calculating the ratio of the dose difference to the set dose value, which reflects the degree of deviation between the actual cumulative exposure dose value and the set dose value.

[0135] Step S170: Determine whether the exposure dose error value meets the requirements.

[0136] In this step, after determining the exposure dose error value, it is necessary to use this value to determine whether the actual exposure effect meets the requirements. If the exposure dose error value does not meet the requirements, it means that the deviation between the actual cumulative exposure dose value and the set dose value is too large and cannot meet the exposure process requirements. The equivalent dose value needs to be adjusted to close the shutter earlier or later, thereby reducing the deviation between the actual cumulative exposure dose value and the set dose value to meet the exposure process requirements.

[0137] In an optional embodiment, step S170 includes: determining whether the exposure dose error value is less than the dose fluctuation threshold; if the exposure dose error value is less than the dose fluctuation threshold, then determining that the exposure dose error value meets the requirements; if the exposure dose error value is greater than or equal to the dose fluctuation threshold, then determining that the exposure dose error value does not meet the requirements.

[0138] Here, the dose fluctuation threshold refers to the maximum value that the exposure dose error can reach when the exposure process requirements are met. The dose fluctuation threshold is used to determine whether the actual cumulative exposure dose value meets the requirements.

[0139] For example, the dose fluctuation threshold can be a percentage, such as 2%.

[0140] In this embodiment, if the exposure dose error is 1.5%, since 1.5% is less than 2%, it indicates that the deviation between the actual cumulative exposure dose value and the set dose value is small, which meets the exposure process requirements and does not require adjustment of the equivalent dose value; if the exposure dose error is 3%, since 3% is greater than 2%, it indicates that the deviation between the actual cumulative exposure dose value and the set dose value is large, which does not meet the exposure process requirements and requires adjustment of the equivalent dose value.

[0141] The following reference Figure 6 and Figure 7 Let's discuss dose repeatability.

[0142] Figure 6 This diagram illustrates the dose repeatability of a set dose provided in an embodiment of this application.

[0143] like Figure 6 As shown, the horizontal axis represents the number of exposures, and the vertical axis represents the dose value, with the unit being mJ / cm². 2 (mJ / cm²), at a set dose value of 235mJ / cm² 2 Under these conditions, the dose repeatability can be measured as 1.5%.

[0144] Dose repeatability refers to the variance of multiple actual cumulative exposure dose values. The smaller the dose repeatability, the better the exposure dose control effect.

[0145] Figure 7 A schematic diagram illustrating the dose repeatability of a set dose two provided in an embodiment of this application is shown.

[0146] like Figure 7 As shown, the horizontal axis represents the number of exposures, and the vertical axis represents the dose value, with the unit being mJ / cm². 2 (mJ / cm²), at a set dose value of 535mJ / cm² 2 Under these conditions, the dose repeatability can be measured as 0.6%.

[0147] In step S180, if the exposure dose error value does not meet the requirements, the equivalent dose value is updated, and the process returns to step S110.

[0148] If the exposure dose error value does not meet the requirements in this step, it indicates that there may be two situations: one is that the shutter starts to close too early, resulting in an exposure time that is too short; the other is that the shutter starts to close too late, resulting in an exposure time that is too long. Therefore, the shutter start-closing time can be re-determined by adjusting the equivalent dose value.

[0149] At the same time, it is necessary to determine which of the two situations mentioned above caused the exposure dose error value to fail to meet the requirements, so as to determine the direction of adjustment of the equivalent dose value.

[0150] In an optional embodiment, step S180 includes: if the exposure dose error value does not meet the requirements, determining whether the actual cumulative exposure dose value is greater than the set dose value; if the actual cumulative exposure dose value is greater than the set dose value, increasing the equivalent time and updating the equivalent dose value using the increased equivalent time; if the actual cumulative exposure dose value is less than the set dose value, decreasing the equivalent time and updating the equivalent dose value using the decreased equivalent time.

[0151] Here, if the actual cumulative exposure dose value is greater than the set dose value, it means the actual exposure dose value exceeds the expected set dose value, and the shutter needs to be closed earlier. This can be achieved by increasing the equivalent time, thus increasing the equivalent dose value. Since the equivalent dose value increases, the target dose value decreases, which in turn advances the shutter closing time, thereby reducing the actual cumulative exposure dose value and narrowing the gap between the actual cumulative exposure dose value and the set dose value. Conversely, if the actual cumulative exposure dose value is less than the set dose value, it means the actual exposure dose value is far less than the expected set dose value, and the shutter needs to be closed later. Here, this can be achieved by decreasing the equivalent time, thus decreasing the equivalent dose value. Since the equivalent dose value decreases, the target dose value increases, which in turn delays the shutter closing time, thereby increasing the actual cumulative exposure dose value and narrowing the gap between the actual cumulative exposure dose value and the set dose value.

[0152] In this embodiment, after the first update of the equivalent time, it is necessary to return to steps S110 to S180 using the first updated equivalent time to determine whether the difference between the actual cumulative exposure dose value corresponding to the first updated equivalent time and the set dose value meets the requirements, that is, to determine whether the exposure dose error value corresponding to the first updated equivalent time meets the requirements. If the exposure dose error value corresponding to the first updated equivalent time does not meet the requirements, the equivalent time is updated a second time, and so on, until the exposure dose error value corresponding to the Nth updated equivalent time meets the requirements after the Nth update.

[0153] It should be noted that when choosing the increase or decrease of the equivalent time, a binary search method can be used. For example, if the initial equivalent time is 25 milliseconds and it is found that the equivalent time needs to be reduced, then the equivalent time after the first update can be 12.5 milliseconds. If the equivalent time after the first update needs to be increased, then the equivalent time after the second update can be 18.75 milliseconds. The calculation formula is 12.5 + (25 - 12.5) / 2 = 18.75 milliseconds.

[0154] Step S190: If the exposure dose error value meets the requirements, the equivalent dose value is applied to the exposure system to expose the silicon wafer.

[0155] In this step, the exposure system can refer to the system used to expose the silicon wafer. The exposure system also includes a shutter to apply the equivalent time obtained by the exposure dose control system to the exposure system.

[0156] It should be noted that the exposure dose control system is mainly used to determine the equivalent time that meets the requirements, so as to ensure that when the equivalent time is applied to the exposure system, the exposure dose control accuracy can be met.

[0157] In one optional embodiment, a target attenuation range corresponding to the set dose value is selected, wherein the target attenuation range is selected from a plurality of candidate attenuation ranges; based on the target attenuation range, the attenuation amplitude of the attenuator is determined; and the attenuator is controlled to attenuate the energy value of the light emitted by the light source by the attenuation amplitude.

[0158] Here, there are multiple candidate attenuation intervals, and different candidate attenuation intervals correspond to different attenuation amplitudes. Based on the set dose value, a target attenuation interval is selected from multiple candidate attenuation intervals to determine the attenuation amplitude corresponding to the target attenuation interval. The energy value of the light emitted by the light source is attenuated using the determined attenuation amplitude.

[0159] In this embodiment, multiple candidate attenuation intervals are designated as a first candidate attenuation interval, a second candidate attenuation interval, a third candidate attenuation interval, and a fourth candidate attenuation interval. The attenuation amplitude corresponding to the first candidate attenuation interval is 0%, the attenuation amplitude corresponding to the second candidate attenuation interval is 25%, the attenuation amplitude corresponding to the third candidate attenuation interval is 50%, and the attenuation amplitude corresponding to the fourth candidate attenuation interval is 75%. It is understood that if the attenuation amplitude corresponding to the first candidate attenuation interval is 0%, the light intensity value of the light passing through the attenuator is not attenuated. If the attenuation amplitude corresponding to the second candidate attenuation interval is 25%, the light intensity value of the light passing through the attenuator is 75% of the light intensity value of the light passing through the attenuator. The attenuation effect of the other candidate attenuation intervals is similar.

[0160] As can be seen, the technical solution provided in this application can improve the accuracy of exposure dose control, keeping it within 2%, thereby ensuring image quality. Simultaneously, since the attenuator can trim the beam, it can broaden the setting range of exposure dose to be applicable to a wider range of processes. Furthermore, when setting the attenuation amplitude for the attenuator, using the maximum light intensity value can also shorten the exposure time as much as possible, thereby improving yield.

[0161] Compared with existing exposure dose control methods, this application can adjust the shutter closing time by continuously adjusting the equivalent time, thereby achieving closed-loop control of the exposure dose. By determining a more suitable shutter closing time, the difference between the actual exposure dose value and the set dose value is minimized, thus improving the accuracy of the exposure dose and solving the problem of low exposure dose control accuracy.

[0162] Based on the same inventive concept, this application also provides an exposure dose control system corresponding to the exposure dose control method based on the exposure dose control system. Since the principle of the system in this application is similar to the exposure dose control method described above in this application, the implementation of the system can refer to the implementation of the method, and the repeated parts will not be described again.

[0163] Please see Figure 8 , Figure 8 This is a schematic diagram of an exposure dose control system provided in an embodiment of this application. Figure 8 As shown, the exposure dose control system includes: a control unit (not shown), a light source 201, a shutter 202, an attenuator 203, a lens group unit 204, a beam splitter 205, and an energy sensor 206.

[0164] The control unit receives a command to turn on the light source and controls the light source 201 to turn on.

[0165] The control unit receives the shutter opening command and controls the shutter 202 to open so that the light emitted by the light source 201 passes through the shutter 202, attenuator 203, lens group unit 204, and beam splitter 205 in sequence before shining on the energy sensor 206.

[0166] The energy sensor 206 collects the energy value of the light and sends the collected energy value to the control unit;

[0167] The control unit receives the energy value sent by the energy sensor 206 and determines the cumulative exposure dose value based on the energy value. The cumulative exposure dose value is used to characterize the exposure dose that accumulates over time from the start time. The start time refers to the moment when the energy sensor 206 collects the energy value of the light.

[0168] The control unit determines whether the cumulative exposure dose value is not less than the target dose value. If it determines that the cumulative exposure dose value is not less than the target dose value, it controls the shutter 202 to start closing. The target dose value is determined by the equivalent dose value. The equivalent dose value is the equivalent value of the exposure dose generated during the shutter closing process and the shake delay process. The shutter closing process is the process from the start of closing the shutter to the complete closing of the shutter. The shake delay process is the process of light leakage caused by the shutter motor shaking after the shutter is completely closed.

[0169] The control unit determines the exposure dose error value based on the actual cumulative exposure dose value, which is the cumulative exposure dose value corresponding to the end of the shake delay after the shutter is completely closed;

[0170] The control unit determines whether the exposure dose error value meets the requirements. If the exposure dose error value does not meet the requirements, it updates the equivalent dose value and uses the updated equivalent dose value to determine the exposure dose error value that meets the requirements. If the exposure dose error value meets the requirements, it applies the equivalent dose value to the exposure system to expose the silicon wafer.

[0171] It should be noted that the exposure dose control system also includes an objective lens 207, a filter 208, and a silicon wafer 209. When light passes through the beam splitter 205, 99% of the light is directed to the objective lens 207, and 1% of the light is directed to the energy sensor 206. This 99% of the light then passes through the filter 208 and illuminates the silicon wafer 209 to expose the silicon wafer.

[0172] Here, the objective lens can refer to a lens group composed of several lenses. The objective lens is used to focus light. For example, the objective lens is located below the beam splitter in the exposure dose control system to focus the transmitted light that has passed through the beam splitter.

[0173] A filter is used to filter out light outside a specified wavelength. For example, the filter is located below the objective lens in an exposure dose control system to filter the light passing through the objective lens.

[0174] Please see Figure 9 , Figure 9 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 9 As shown, the electronic device 300 includes a processor 310, a memory 320, and a bus 330.

[0175] The memory 320 stores machine-readable instructions executable by the processor 310. When the electronic device 300 is running, the processor 310 and the memory 320 communicate via the bus 330. When the machine-readable instructions are executed by the processor 310, they can perform the operations described above. Figure 1 The steps of the exposure dose control method based on the exposure dose control system in the method embodiment shown are specifically implemented in the method embodiment and will not be repeated here.

[0176] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can perform the above-described actions. Figure 1 The steps of the exposure dose control method based on the exposure dose control system in the method embodiment shown are specifically implemented in the method embodiment and will not be repeated here.

[0177] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0178] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0179] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0180] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0181] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0182] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An exposure dose control method based on an exposure dose control system, characterized by, The exposure dose control system comprises a light source, a shutter, an attenuator, a mirror unit, a beam splitter and an energy sensor; The exposure dose control method comprises: (A) receiving a light source opening instruction to control the light source to open; (B) receiving a shutter opening instruction to control the shutter to open, so that the light emitted by the light source irradiates on the energy sensor after sequentially passing through the shutter, the attenuator, the mirror unit and the beam splitter; (C) receiving an energy value collected by the energy sensor, determining an accumulated exposure dose value based on the energy value, the accumulated exposure dose value being used to represent the exposure dose accumulated over time since a starting time, the starting time being the time when the energy sensor collects the energy value of the light; (D) determining whether the accumulated exposure dose value is not less than a target dose value, the target dose value being determined by an equivalent dose value, the equivalent dose value being an equivalent value of the exposure dose generated in a shutter closing process and a jitter delay process, the shutter closing process being a process in which the shutter starts to close to completely closes, the jitter delay process being a process in which light leaks due to the jitter of the shutter motor after the shutter completely closes; (E) if the accumulated exposure dose value is not less than the target dose value, controlling the shutter to start to close; (F) taking the accumulated exposure dose value corresponding to a jitter delay end time as an actual accumulated exposure dose value, the jitter delay end time being a time after a set time length from a shutter completely closing time; (G) determining an exposure dose error value based on the actual accumulated exposure dose value; (H) determining whether the exposure dose error value meets a requirement; (I) if the exposure dose error value does not meet the requirement, updating the equivalent dose value and returning to step (B); (J) if the exposure dose error value meets the requirement, applying the equivalent dose value to an exposure system to expose a silicon wafer. Step (I) comprises: If the exposure dose error value does not meet the requirement, determining whether the actual accumulated exposure dose value is greater than a set dose value; If the actual accumulated exposure dose value is greater than the set dose value, increasing an equivalent time, and updating the equivalent dose value by using the increased equivalent time; If the actual accumulated exposure dose value is less than the set dose value, decreasing the equivalent time, and updating the equivalent dose value by using the decreased equivalent time.

2. The method of claim 1, wherein, Step (C) comprises: (C1) obtaining an energy value of the energy sensor under no light; (C2) determining the accumulated exposure dose value based on the energy value under no light and the energy value of the light.

3. The method of claim 2, wherein, Step (C2) comprises: Determining a difference between the energy value of the light and the energy value under no light as a target energy value; Determining a target function based on the target energy value and a conversion factor; Determining the accumulated exposure dose value by integrating the target function over a time interval.

4. The method of claim 1, wherein, Step (G) comprises: Determining an absolute value of a difference between a set dose value and the actual accumulated exposure dose value as a dose difference value; Determining the exposure dose error value by dividing the dose difference value by the set dose value.

5. The method of claim 1, wherein, Step (H) comprises: determining whether the exposure dose error value is less than a dose float threshold value; if the exposure dose error value is less than the dose float threshold value, determining that the exposure dose error value meets a requirement; if the exposure dose error value is greater than or equal to the dose float threshold value, determining that the exposure dose error value does not meet the requirement.

6. The method of claim 4, wherein, The method further comprises: selecting a target attenuation interval corresponding to the set dose value, the target attenuation interval being an attenuation interval selected from a plurality of candidate attenuation intervals; determining an attenuation amplitude of an attenuator based on the target attenuation interval; controlling the attenuator to attenuate the energy value of the light emitted by the light source by the attenuation amplitude.

7. An exposure dose control system characterized by comprising: The system comprises a control unit, a light source, a shutter, an attenuator, a lens unit, a beamsplitter, and an energy sensor; the control unit receives a light source opening instruction to control the light source to open; the control unit receives a shutter opening instruction to control the shutter to open, so that the light emitted by the light source passes through the shutter, the attenuator, the lens unit, and the beamsplitter in sequence and then irradiates on the energy sensor; the energy sensor collects the energy value of the light and sends the collected energy value to the control unit; the control unit receives the energy value sent by the energy sensor, determines a cumulative exposure dose value based on the energy value, the cumulative exposure dose value being used to represent the exposure dose accumulated over time since a start time, the start time being the time when the energy sensor collects the energy value of the light; the control unit determines whether the cumulative exposure dose value is not less than a target dose value, and if it is determined that the cumulative exposure dose value is not less than the target dose value, controls the shutter to start closing, the target dose value being determined by an equivalent dose value, the equivalent dose value being an equivalent value of the exposure dose generated during a shutter closing process and a jitter delay process, the shutter closing process being the process of the shutter from starting to close to completely closing, and the jitter delay process being the process of light leakage caused by the jitter of the shutter motor after the shutter completely closes; the control unit determines an exposure dose error value based on an actual cumulative exposure dose value, the actual cumulative exposure dose value being the cumulative exposure dose value corresponding to the end time of the jitter delay process after the shutter completely closes; the control unit determines whether the exposure dose error value meets a requirement, and if the exposure dose error value does not meet the requirement, updates the equivalent dose value and determines an exposure dose error value meeting the requirement by using the updated equivalent dose value; if the exposure dose error value meets the requirement, applies the equivalent dose value to an exposure system to expose a silicon wafer; The control unit is specifically configured to: if the exposure dose error value does not meet the requirement, determine whether the actual cumulative exposure dose value is greater than a set dose value; if the actual cumulative exposure dose value is greater than the set dose value, increase an equivalent time, and update the equivalent dose value by using the increased equivalent time; if the actual cumulative exposure dose value is less than the set dose value, decrease an equivalent time, and update the equivalent dose value by using the decreased equivalent time.

8. An electronic device, comprising: ​ A processor, a storage medium storing machine readable instructions executable by the processor, and a bus for communication between the processor and the storage medium when the electronic device is running, the processor executing the machine readable instructions to perform the steps of the exposure dose control method of any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, A computer program stored on the computer readable storage medium, the computer program being executed by the processor to perform the steps of the exposure dose control method of any one of claims 1 to 6.

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