Exposure system and control method thereof

Abstract

The invention provides an exposure system and a control method thereof, relates to the technical field of photoetching, and can perform real-time data calculation on exposure dose and exposure time by combining the exposure system and shutter control to obtain accurate data in a single opening and closing process of a shutter. Therefore, data errors caused by factors such as instability of an exposure system, temperature and pressure are reduced, and accurate control of exposure dose is realized.

Description

Technical Field

[0001] The present application relates to the field of photolithography technology, and in particular to an exposure system and a control method thereof. Background Art

[0002] Photolithography is an important part of the production process of semiconductor devices. The process of photolithography is generally divided into silicon wafer pretreatment, glue coating, pre-baking, exposure, development, post-baking, etching, glue stripping and overlaying, and each link affects and restricts each other. Among them, the exposure process refers to the use of a light beam of a specific wavelength and intensity to irradiate the photoresist through the mask plate, so that the irradiated part undergoes a photochemical reaction, so that after development, a pattern corresponding to the mask plate can be obtained.

[0003] The exposure dose is the product of the light intensity and the exposure time, which is used to represent the exposure energy obtained by the photoresist surface. Because the exposure dose is a key parameter affecting the exposure quality, it needs to be effectively controlled. The existing method of controlling the exposure dose is mainly to control it according to the pre-calculated equipment parameters before controlling the shutter, but there may be certain fluctuations in the actual exposure process, so it is difficult to accurately control the exposure dose. Summary of the invention

[0004] The purpose of the present application is to provide an exposure system and a control method thereof in view of the deficiencies in the above-mentioned prior art.

[0005] To achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0006] In one aspect of an embodiment of the present application, a method for controlling an exposure system is provided, wherein the exposure system includes a light source, a shutter, a mask plate, and a stage for carrying a wafer, which are sequentially arranged along a main light path, and a single opening and closing of the shutter includes a continuous gradual opening stage, a fully opening stage, and a gradual closing stage; the method includes:

[0007] Acquiring target information, where the target information is a target exposure dose or a target exposure time;

[0008] When the target information is a target exposure dose, a preset exposure dose accumulated when the stage is in a shutter gradually opening stage and a shutter gradually closing stage is obtained;

[0009] Determine a first exposure dose accumulated when the stage is in a fully opened shutter stage according to a target exposure dose and a preset exposure dose;

[0010] Acquire a first illuminance at the stage according to a preset sampling frequency, wherein the first illuminance is characterized by the illuminance at the stage at any sampling moment when the shutter is fully opened;

[0011] Determine first duration information of the shutter being in a fully open stage according to the first exposure dose and the first illumination;

[0012] Determine the start time of the shutter gradually closing phase based on the first duration information;

[0013] When the target information is the target exposure time, obtaining preset duration information of the shutter gradually opening stage and the shutter gradually closing stage;

[0014] Determine first duration information of the shutter being in a fully open stage according to the target exposure time and preset duration information;

[0015] Acquire a first illuminance at the stage according to a preset sampling frequency, wherein the first illuminance is characterized by the illuminance at the stage at any sampling moment when the shutter is fully opened;

[0016] A first actual exposure dose accumulated when the stage is in a stage where the shutter is fully opened is determined according to the first duration information and the first light illumination.

[0017] Optionally, the exposure system further comprises a beam splitter element located in the main light path, the beam splitter element being used to split the detection light beam from the main light path;

[0018] Acquiring the first light intensity at the stage according to the preset sampling frequency includes:

[0019] Collecting a second illuminance of the detection light beam according to a preset sampling frequency, where the second illuminance is characterized by the illuminance of the detection light beam at any sampling moment when the shutter is in a fully open stage;

[0020] The first illumination at the stage is determined according to the second illumination, the transmission-reflection ratio of the light-splitting element and the transmittance of the mask plate.

[0021] Optionally, determining the first duration information of the shutter being in the fully open stage according to the first exposure dose and the first light illumination includes:

[0022] The first duration information is determined according to the first exposure dose, the first illuminance and the exposure time model, wherein the exposure time model is used to characterize the correspondence between the first exposure dose and the first duration information.

[0023] Optionally, the exposure time model is: Where D is the first exposure dose, K1 is the transmittance-reflection ratio of the spectroscopic element, K2 is the transmittance of the mask, Δt is the sampling interval, and E Bt is the second light illumination, and T is the first duration information.

[0024] Optionally, determining the first actual exposure dose accumulated when the stage is in the fully opened stage of the shutter according to the first duration information and the first light illumination includes:

[0025] A first actual exposure dose is determined according to the first duration information, the first illuminance and an exposure dose model, wherein the exposure dose model is used to characterize the correspondence between the first duration information and the first actual exposure dose.

[0026] Optionally, the exposure dose model is: Where D is the first exposure dose, T is the first duration information, and E Bt is the second illumination, Δt is the sampling interval, K1 is the transmission-reflection ratio of the beam splitter, and K2 is the transmittance of the mask.

[0027] Optionally, the mask plate may be placed in the main light path or removed from the main light path. Before acquiring the target information, the method further includes:

[0028] When the mask plate is removed from the main light path, the shutter is controlled to be in a fully open stage, and a first test light illuminance at the stage and a second test light illuminance of the detection light beam are respectively obtained;

[0029] The transmission-reflection ratio of the light splitting element is determined according to the first test light illumination and the second test light illumination.

[0030] Optionally, the mask plate may be placed in the main light path or removed from the main light path. Before acquiring the target information, the method further includes:

[0031] When the mask plate is removed from the main light path, the shutter is controlled to be in a fully open stage to obtain a second test light intensity of the detection light beam;

[0032] Determine a third test light illuminance at the stage according to the transmission-reflection ratio of the beam splitter and the second test light illuminance, the third test light illuminance being used to characterize the light illuminance at the stage when the mask is removed from the main light path and the shutter is in a fully open stage;

[0033] When the mask plate is located in the main light path, the shutter is controlled to be in a fully open stage to obtain a fourth test light intensity at the stage;

[0034] The transmittance of the mask plate is determined according to the third test light illumination and the fourth test light illumination.

[0035] Optionally, after obtaining preset duration information of the shutter gradually opening stage and the shutter gradually closing stage, and before determining the first duration information of the shutter being in the fully opening stage according to the target exposure time and the preset duration information, the method further includes:

[0036] Determine whether the target exposure time is less than or equal to the preset duration information;

[0037] If yes, then re-acquire the updated target information;

[0038] If not, continue to determine the first duration information of the shutter being in the fully open stage according to the target exposure time and the preset duration information.

[0039] On the other hand, an embodiment of the present application provides an exposure system controlled by any of the above-mentioned exposure system control methods, the exposure system includes a light source, a shutter, a mask plate and a carrier for carrying a wafer arranged in sequence along a main light path, and a light beam of the light source emitted from the shutter is incident on the carrier through the mask plate.

[0040] The beneficial effects of this application include:

[0041] The present application provides an exposure system and a control method thereof. By combining the exposure system and shutter control, real-time data calculation of exposure dose and exposure time can be performed, and accurate data of a single shutter opening and closing process can be obtained, thereby reducing data errors caused by factors such as instability of the exposure system, temperature, pressure, etc., and achieving precise control of the exposure dose. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 A schematic diagram of the structure of an exposure system provided in an embodiment of the present application;

[0044] Figure 2 A schematic diagram of the relationship between exposure dose and time axis provided in an embodiment of the present application;

[0045] Figure 3 A schematic flow chart of an exposure system control method provided in an embodiment of the present application.

[0046] Icons: 101-light source; 102-shutter; 103-uniform light element; 104-spectrometric element; 105-light intensity detector; 106-variable slit; 107-relay; 108-mask; 109-objective lens assembly; 110-stage; 111-wafer; 112-illuminance meter. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. It should be noted that, in the absence of conflict, the various features in the embodiments of the present application can be combined with each other, and the combined embodiments are still within the scope of protection of the present application.

[0048] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the application is usually placed when in use. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0049] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0050] In one aspect of the embodiments of the present application, an exposure system is provided. Figure 1 As shown, the exposure system includes a light source 101 , a shutter 102 , a mask plate 108 , and a stage 110 for carrying a wafer 111 , which are sequentially arranged along a main light path.

[0051] Whether the light beam emitted by the light source 101 can continue to propagate backward through the shutter 102 depends on the opening and closing of the shutter 102. For ease of understanding, the single opening and closing of the shutter 102 is defined as: the shutter 102 is completely closed and then opened and then completely closed again. Therefore, the single opening and closing process of the shutter 102 includes a gradual opening stage, a fully open stage, and a gradual closing stage that are continuous in the time dimension, wherein the gradual opening stage refers to the process of the shutter 102 switching from being completely closed to being fully opened, the fully open stage refers to the process of the shutter 102 remaining fully open, and the gradual closing stage refers to the process of the shutter 102 switching from being fully opened to being fully closed.

[0052] It should be understood that when the shutter 102 is in a gradually opening stage, the light-transmitting window area of ​​the shutter 102 gradually increases; when the shutter 102 is in a fully opening stage, the light-transmitting window area of ​​the shutter 102 is the largest and remains unchanged; when the shutter 102 is in a gradually closing stage, the light-transmitting window area of ​​the shutter 102 gradually decreases.

[0053] When the light source 101 is turned on and emits a light beam, the shutter 102 can be controlled to perform a single opening and closing, so that the light beam passes through the shutter 102 during the single opening and closing process, and then transmits from the photomask plate 108 and finally enters the stage 110 from point G. When a wafer 111 is placed on the stage 110, the light beam transmitted from the photomask plate 108 can be irradiated to the wafer 111 through point G, thereby realizing exposure of the wafer 111. When no wafer 111 is placed on the stage 110, the light beam transmitted from the photomask plate 108 can be irradiated to each detection point in each exposure area of ​​the stage 110 through point G.

[0054] Of course, in actual manufacturing, the wafer 111 may need to be exposed multiple times, so the shutter 102 can be controlled to open and close multiple times to meet the exposure requirements of the wafer 111. In addition, when multiple areas on the wafer 111 need to be exposed, the stage 110 can also be controlled to move, thereby changing the position where the light beam irradiates the wafer 111, so as to meet the exposure requirements of different areas.

[0055] In some possible implementations, the light source 101 may be a mercury lamp light source 101 , an LED light source 101 , or the like.

[0056] In some possible implementations, such as Figure 1 As shown, the exposure system further includes a spectroscopic element 104 and a light intensity detector 105. The spectroscopic element 104 is located in the main light path between the shutter 102 and the mask plate 108. The spectroscopic element 104 can separate a detection beam from the main light path so that the detection beam enters the light intensity detector 105 via point B, so that the light intensity detector 105 can obtain the light intensity at point B. Specifically, the spectroscopic element 104 can be a semi-transparent and semi-reflective mirror. Therefore, after the light beam passing through the shutter 102 is incident on the semi-transparent and semi-reflective mirror, a part of the light beam continues to propagate along the main light path after being transmitted through the semi-transparent and semi-reflective mirror, and another part of the light beam is reflected by the semi-transparent and semi-reflective mirror and enters the light intensity detector 105 via point B as a detection beam. Of course, in other embodiments, a part of the light beam can also continue to propagate along the main light path after being reflected by the semi-transparent and semi-reflective mirror, and another part of the light beam can enter the light intensity detector 105 via point B as a detection beam after being transmitted through the semi-transparent and semi-reflective mirror.

[0057] In some possible implementations, such as Figure 1As shown, the mask plate 108 can be placed in the main light path or removed from the main light path, meeting the multi-scenario requirements of the exposure system not to set or replace the mask plate 108. Specifically, the mask plate can be placed on the mask table or removed from the mask table by an external robot. When the mask plate is placed on the mask table, it is located in the main light path. When the mask plate is removed from the mask table, it is removed from the main light path.

[0058] In some possible implementations, such as Figure 1 As shown, the exposure system further includes an illuminance meter 112 disposed on the stage 110 , so that during the test, the illuminance at the G point can be obtained through the illuminance meter 112 .

[0059] In some possible implementations, such as Figure 1 As shown, the exposure system further includes one or more of a light homogenizing element 103 , a variable slit 106 , a relay 107 , and an objective lens assembly 109 arranged in the main light path.

[0060] It should be understood that the above-mentioned exposure systems can be controlled by any subsequent exposure system control method. Therefore, for the convenience of control, the exposure system may include a control unit, and the control unit can call the subsequent exposure system control method so as to be able to collect and process data in real time during a single opening and closing of the shutter 102, thereby accurately controlling the exposure dose.

[0061] On the other hand, an embodiment of the present application provides an exposure system control method, which, by combining the exposure system and the shutter 102 control, can perform real-time data calculation of the exposure dose and exposure time, and obtain accurate data during a single opening and closing process of the shutter 102, thereby reducing data errors caused by factors such as instability of the exposure system, temperature, pressure, etc., and achieving precise control of the exposure dose.

[0062] Based on the above description of the exposure system, it can be known that the shutter 102 single opening and closing includes a gradual opening stage, a fully opening stage and a gradual closing stage in a continuous time dimension. Figure 2 , the entire process of a single opening and closing of the shutter 102 is shown on the time axis t, specifically:

[0063] The start time of the gradual opening phase of the shutter 102 is denoted by t1, and the end time is denoted by t2;

[0064] The start time of the fully open phase of the shutter 102 is represented by t2, and the end time is represented by t3;

[0065] The start time of the gradual closing phase of the shutter 102 is represented by t3, and the end time is represented by t4;

[0066] Therefore, the time period when the shutter 102 is in the gradually opening stage is from t1 to t2, the time period when the shutter 102 is in the fully opening stage is from t2 to t3, and the time period when the shutter 102 is in the gradually closing stage is from t3 to t4.

[0067] Only when the shutter 102 is opened and closed once, the stage 110, the wafer 111 or the G point will be irradiated by the light beam to generate illumination, which will then accumulate to form an exposure dose. Figure 2 , the accumulated exposure dose at each time point of a single opening and closing of the shutter 102 is shown on the time axis t, specifically:

[0068] At time t1, the accumulated exposure dose at point G is represented by D1 (at this time, because the shutter 102 has not yet opened, D1 is usually zero);

[0069] At time t2, the accumulated exposure dose at point G is represented by D2 (the accumulated exposure dose during the entire time period from t1 to t2 is represented by D2-D1);

[0070] At time t3, the accumulated exposure dose at point G is represented by D3 (the accumulated exposure dose in the entire time period from t2 to t3 is represented by D3-D2);

[0071] At time t4, the accumulated exposure dose at point G is represented by D4 (the accumulated exposure dose in the entire time period from t3 to t4 is represented by D4-D3).

[0072] Please refer to Figure 3 As shown, the exposure system control method includes:

[0073] S10: Acquire target information, where the target information is a target exposure dose or a target exposure time.

[0074] The user can input target information to the exposure system, and the input target information can be a target exposure dose or a target exposure time, that is, the user gives a target exposure dose or a target exposure time. The control unit controls the exposure dose and the exposure time by obtaining the target information.

[0075] S21: When the target information is a target exposure dose, a preset exposure dose accumulated when the stage is in a shutter gradually opening stage and a shutter gradually closing stage is obtained.

[0076] S22: Determine a first exposure dose accumulated when the stage is in a fully open shutter stage according to the target exposure dose and the preset exposure dose.

[0077] S23: Acquire a first illuminance at the stage according to a preset sampling frequency, where the first illuminance is characterized by the illuminance of the stage at any sampling moment when the shutter is in a fully open stage.

[0078] S24: Determine first duration information of the shutter being in the fully open stage according to the first exposure dose and the first light intensity.

[0079] S25: Determine a start time of the shutter gradually closing phase based on the first duration information.

[0080] Usually, the speed of the shutter 102 in the gradual opening stage and the gradual closing stage is executed according to the preset parameters of the system, so the exposure dose accumulated at the point G in the gradual opening stage and the gradual closing stage of the shutter 102 can be predicted. When the wafer 111 is placed at the point G, it is the preset exposure dose accumulated by the wafer 111 in the gradual opening stage and the gradual closing stage of the shutter 102. When the wafer 111 is not placed at the point G, it is the preset exposure dose accumulated in each exposure area on the stage 110 in the gradual opening stage and the gradual closing stage of the shutter 102. In some possible implementations, the speed of the shutter 102 in the gradual opening stage and the speed of the gradual closing stage can be equal, and the exposure dose accumulated at the point G in the gradual opening stage of the shutter 102 and the exposure dose accumulated at the point G in the gradual closing stage of the shutter 102 can be equal.

[0081] After the user inputs the target information, the control unit parses the target information: when the target information is the target exposure dose, it means that the control unit needs to accurately control the duration required for a single opening and closing of the shutter 102, so that when the single opening and closing process of the shutter 102 ends, the accumulated exposure dose at point G is equal to the target exposure dose.

[0082] The target exposure dose can be divided into the accumulated exposure dose required in the gradual opening stage, the accumulated first exposure dose required in the fully opening stage, and the accumulated exposure dose required in the gradual closing stage according to the stages included in the opening and closing of the shutter 102.

[0083] After obtaining the target information, the control unit continues to obtain a preset exposure dose, wherein the preset exposure dose is the sum of the accumulated exposure dose required in the gradual opening stage and the accumulated exposure dose required in the gradual closing stage. Accordingly, the first exposure dose to be exposed can be determined according to the target exposure dose and the preset exposure dose.

[0084] After acquiring the target information, the control unit starts to control the shutter 102 to perform a single opening and closing: the shutter 102 starts to perform the gradual opening stage at t1 and ends at t2. During this process, the accumulated exposure dose at point G is D2-D1. Then the shutter 102 starts to perform the full opening stage at t2 and ends at t3. During this stage, the first light illumination at point G (that is, at the wafer 111 of the stage 110 or at each detection point in each exposure area of ​​the stage 110) is acquired in real time according to the preset sampling frequency (therefore, the first light illumination is characterized by the light illumination of the wafer 111 or each detection point at any sampling moment when the shutter 102 is in the full opening stage), so that the light illumination data at point G can be updated in real time according to the preset sampling frequency from t2 to t3.

[0085] The control unit combines the first exposure dose and the first light illumination updated in real time to determine the first duration information (t2 to t3) that the shutter 102 needs to remain in the fully open stage under the premise that D3-D2 is equal to the first exposure dose.

[0086] After the first time information is determined, t3 is determined, which is the start time of the gradual closing stage of the shutter 102. The shutter 102 then starts to perform the gradual closing stage at time t3 and ends at time t4. During this process, the accumulated exposure dose at point G is D4-D3. It should be understood that the sum of D2-D1 and D4-D3 is equal to the preset exposure dose.

[0087] After specifying the target exposure dose, by controlling the single opening and closing time of the shutter 102, the accumulated exposure dose D4-D1 at the G point can be equal to the target exposure dose during the single opening and closing process of the shutter 102.

[0088] Optionally, considering that the wafer 111 needs to be placed at the G point during the actual exposure process, it is inconvenient to directly collect the first light intensity at the G point during the single opening and closing process of the shutter 102. At this time, the detection light beam can be separated from the main light path by the beam splitter 104, and the light intensity detector 105 collects the second light intensity of the detection light beam according to the preset sampling frequency, and then the first light intensity is converted by the second light intensity. Specifically:

[0089] S23: Acquiring a first light intensity at the stage according to a preset sampling frequency includes:

[0090] S231: collecting a second illuminance of the detection light beam according to a preset sampling frequency, where the second illuminance is characterized by the illuminance of the detection light beam at any sampling moment when the shutter is in a fully open stage.

[0091] S232: Determine the first illumination at the stage according to the second illumination, the transmission-reflection ratio of the beam splitter and the transmittance of the mask.

[0092] Since the detection light beam irradiated to point B and the light beam irradiated to point G are both originated from the light source, the first light illuminance and the second light illuminance have a conversion relationship. That is, the first light illuminance is calculated based on the second light illuminance, the transmission-reflection ratio of the light-splitting element 104, and the transmittance of the mask plate 108. Since the acquisition frequency of the second light illuminance is the preset acquisition frequency, the first light illuminance is synchronously updated every time the second light illuminance is updated.

[0093] Optionally, S24 includes: determining first duration information according to the first exposure dose, the first illuminance and an exposure time model, wherein the exposure time model is used to characterize the correspondence between the first exposure dose and the first duration information.

[0094] Optionally, the exposure time model is: Wherein, D is the first exposure dose, K1 is the transmission-reflection ratio of the light splitting element 104, K2 is the transmittance of the photomask 108, Δt is the sampling interval, and E Bt is the second light illumination, and T is the first duration information.

[0095] Optionally, considering that the time required for data transmission (referring to the time when the control unit sends the instruction to the time when the shutter 102 receives the instruction) is T1, if T1 is equal to the time from t1 to t2, and is also equal to the time from t3 to t4, then after calculating T, the control unit needs to send an instruction to execute the gradual closing stage to the shutter 102 at the time of t1 to t2 + T.

[0096] Optionally, the preset exposure dose can be determined through testing before the actual exposure. Specifically: before executing S10, the shutter 102 is controlled to continuously and cyclically execute the gradual opening stage and the gradual closing stage (that is, the full opening stage is not executed), and the time variation curve of the light intensity detector 105 at point B is obtained. The total exposure dose is obtained by accumulating, and the single exposure dose of the shutter 102 executing the gradual opening stage and the gradual closing stage once is obtained by taking the average while ensuring the stability of the system. This method can avoid the problem of irregular and uncalculatable light window of the shutter 102.

[0097] S31: When the target information is the target exposure time, obtain preset duration information of the shutter gradually opening stage and the shutter gradually closing stage.

[0098] S32: Determine first duration information of the shutter being in a fully open stage according to the target exposure time and the preset duration information.

[0099] S33: Acquire a first illuminance at the stage according to a preset sampling frequency, where the first illuminance is characterized by the illuminance of the stage at any sampling moment when the shutter is in a fully open stage.

[0100] S34: Determine, according to the first duration information and the first light intensity, a first actual exposure dose accumulated when the stage is in the fully opened stage of the shutter.

[0101] Usually, the speed of the shutter 102 in the gradual opening stage and the gradual closing stage is executed according to the preset parameters of the system, so the accumulated exposure dose and duration at the point G in the gradual opening stage and the gradual closing stage of the shutter 102 can be predicted, that is, the preset duration information of the gradual opening stage and the gradual closing stage of the shutter 102. In some possible implementations, the duration of the gradual opening stage of the shutter 102 and the duration of the gradual closing stage can be equal, and the accumulated exposure dose at the point G in the gradual opening stage of the shutter 102 and the accumulated exposure dose at the point G in the gradual closing stage of the shutter 102 can be equal.

[0102] After the user inputs the target information, the control unit parses the target information: when the target information is the target exposure time, it means that the shutter 102 needs to be opened and closed once according to the target exposure time through the control unit, and during the single opening and closing process of the shutter 102, the illuminance data at point G is obtained in real time, so as to calculate the accumulated exposure dose at point G in real time.

[0103] The target exposure time can be divided into the duration required for the gradual opening stage, the first duration information required for the full opening stage, and the duration required for the gradual closing stage according to the stages included in the opening and closing of the shutter 102.

[0104] After obtaining the target information, the control unit continues to obtain the preset duration information, wherein the preset duration information is the sum of the duration required for the gradual opening stage and the duration required for the gradual closing stage. Accordingly, the first duration information can be determined according to the target exposure time and the preset duration information.

[0105] After acquiring the target information, the control unit starts to control the shutter 102 to perform a single opening and closing: the shutter 102 starts to perform the gradual opening stage at t1 and ends at t2, that is, from t1 to t2, the accumulated exposure dose at point G during this process is D2-D1. Then the shutter 102 starts to perform the full opening stage at t2 and ends at t3. During this stage, the first illuminance at point G (that is, at the wafer 111 or each detection point) is acquired in real time according to the preset sampling frequency (therefore, the first illuminance is characterized by the illuminance of the wafer 111 or each detection point at any sampling moment when the shutter 102 is in the full opening stage), so that the illuminance data at point G can be updated in real time according to the preset sampling frequency from t2 to t3.

[0106] On the premise that t2 to t3 is equal to the first duration information, the control unit integrates the first light illuminance updated in real time in combination with the first duration information to determine the first actual exposure dose (D3-D2) accumulated at point G during the time period from t2 to t3.

[0107] Then the control unit continues to control the shutter 102 to start the gradual closing phase at time t3 until it ends at time t4. During this process, the accumulated exposure dose at point G is D4-D3. It should be understood that both D2-D1 and D4-D3 can be predicted.

[0108] After the target exposure time is specified, the single opening and closing duration of the shutter 102 is controlled according to the target exposure time, and during the single opening and closing process of the shutter 102, the accumulated exposure dose is calculated using the first photometer 112 updated in real time.

[0109] Optionally, considering that the wafer 111 may need to be placed at the G point during the actual exposure process, it is inconvenient to directly collect the first light intensity at the G point during the single opening and closing process of the shutter 102. At this time, the detection light beam can be separated from the main light path by the beam splitter 104, and the second light intensity of the detection light beam can be collected by the light intensity detector 105 according to the preset sampling frequency, and then the first light intensity is converted by the second light intensity. Specifically:

[0110] S23: Acquiring a first light intensity at the stage according to a preset sampling frequency includes:

[0111] S231: collecting a second illuminance of the detection light beam according to a preset sampling frequency, where the second illuminance is characterized by the illuminance of the detection light beam at any sampling moment when the shutter is in a fully open stage.

[0112] S232: Determine the first illumination at the stage according to the second illumination, the transmission-reflection ratio of the beam splitter and the transmittance of the mask.

[0113] Since the detection light beam irradiated to point B and the light beam irradiated to point G are both originated from the light source, the first light illuminance and the second light illuminance have a conversion relationship. That is, the first light illuminance is calculated based on the second light illuminance, the transmission-reflection ratio of the light-splitting element 104, and the transmittance of the mask plate 108. Since the acquisition frequency of the second light illuminance is the preset acquisition frequency, the first light illuminance is synchronously updated every time the second light illuminance is updated.

[0114] Optionally, S34 includes: determining a first actual exposure dose according to the first duration information, the first illuminance and an exposure dose model, wherein the exposure dose model is used to characterize the correspondence between the first duration information and the first actual exposure dose.

[0115] Optionally, the exposure dose model is: Where D is the first exposure dose, T is the first duration information, and E Bt is the second illumination, Δt is the sampling interval, K1 is the transmission-reflection ratio of the light-splitting element 104 , and K2 is the transmittance of the mask plate 108 .

[0116] Optionally, after obtaining the preset duration information of the gradual opening stage and the gradual closing stage of the shutter 102, and before determining the first duration information of the shutter 102 in the fully opening stage according to the target exposure time and the preset duration information, the method also includes: judging whether the target exposure time is less than or equal to the preset duration information; if so, it means that the first duration information does not exist, and it is necessary to re-acquire the updated target information and then make a judgment; if not, continue to execute S32.

[0117] Optionally, in the above S232, the transmission-reflection ratio of the light splitting element 104 can be determined by testing before actual exposure. Therefore, before acquiring the target information, the method further includes:

[0118] S41: When the mask plate 108 is removed from the main light path, the shutter 102 is controlled to be in a fully open stage, and a first test light illumination at the stage 110 and a second test light illumination of the detection light beam are respectively obtained.

[0119] S42: Determine the transmission-reflection ratio of the light splitting element 104 according to the first test light illumination and the second test light illumination.

[0120] During the test, the mask plate 108 can be first removed from the main light path, and then the shutter 102 can be controlled to be in the fully open stage. At this time, the illuminance meter 112 on the stage 110 can be used to collect the first test light illuminance at point G (which can be achieved by controlling the movement of the stage 110), and the light intensity detector 105 can be used to collect the second test light illuminance at point B. In this way, the transmission-reflection ratio of the beam splitter 104 can be determined by the ratio of the first test light illuminance to the second test light illuminance, so that the transmission-reflection ratio of the beam splitter 104 can be directly called after the control unit obtains the target information.

[0121] In addition, when measuring the transmission-reflection ratio of the spectroscopic element 104 , multiple measurements may be performed and the transmission-reflection ratios of the multiple measurements may be averaged, so that the transmission-reflection ratio of the spectroscopic element 104 measured finally is more accurate.

[0122] Optionally, in the above S232, the transmittance of the mask plate 108 can be determined by testing before actual exposure. Therefore, before obtaining the target information, the method further includes:

[0123] S51: When the mask plate 108 is removed from the main light path, the shutter 102 is controlled to be in a fully open stage to obtain a second test light intensity of the detection light beam.

[0124] S52: Determine a third test light illumination at the stage 110 according to the transmission-reflection ratio of the beam splitter 104 and the second test light illumination, wherein the third test light illumination is used to characterize the light illumination at the stage 110 when the mask plate 108 is removed from the main light path and the shutter 102 is in a fully open stage.

[0125] S53: When the mask plate 108 is located in the main light path, the shutter 102 is controlled to be in a fully open stage, and a fourth test light illumination at the stage 110 is obtained.

[0126] S54: Determine the transmittance of the mask plate 108 according to the third test light illumination and the fourth test light illumination.

[0127] During the test, the mask plate 108 can be first removed from the main light path, and then the shutter 102 is controlled to be in the fully open stage. At this time, the light intensity detector 105 is used to collect the second test light illuminance at point B. Then the transmission-reflection ratio of the spectroscopic element 104 and the product of the second test light illuminance are used as the third test light illuminance at point G (without the mask plate 108). Then, the mask plate 108 is placed in the main light path again, and the shutter 102 is kept in the fully open stage. The illuminance meter 112 on the stage 110 is used to collect the fourth test light illuminance at point G (with the mask plate 108). In this way, the transmittance of the mask plate 108 is determined according to the ratio of the third test light illuminance to the fourth test light illuminance.

[0128] It should be understood that when the photomask 108 in the main light path is replaced, it is necessary to re-measure the transmittance of the photomask 108. In addition, considering that the distribution of light transmittance in the photomask 108 may not be uniform, when measuring the transmittance of the photomask 108, the illuminance data of multiple measuring points in the exposure area at point G can be collected, and then averaged, so that the transmittance of the photomask 108 finally measured is more accurate.

[0129] Of course, the transmission-reflection ratio of the light-splitting element 104 used in the process of measuring the transmittance of the mask plate 108 can be the data measured by S41 and S42.

[0130] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An exposure system control method, characterized in that: The exposure system includes a light source, a shutter, a mask plate and a stage for carrying a wafer which are sequentially arranged along a main light path, and a single opening and closing of the shutter includes a continuous gradual opening stage, a full opening stage and a gradual closing stage; the method includes: Acquiring target information, wherein the target information is a target exposure dose or a target exposure time; When the target information is a target exposure dose, obtaining a preset exposure dose accumulated by the stage in the gradual opening stage and the gradual closing stage of the shutter; Determine, according to the target exposure dose and the preset exposure dose, a first exposure dose accumulated by the stage when the shutter is fully opened; Acquire a first illuminance at the stage according to a preset sampling frequency, wherein the first illuminance is characterized by the illuminance at the stage at any sampling moment when the shutter is in a fully open stage; Determining first duration information of the shutter being in a fully open stage according to the first exposure dose and the first light illumination; Determine the start time of the shutter gradually closing phase based on the first duration information; When the target information is a target exposure time, obtaining preset duration information of the shutter gradually opening stage and the shutter gradually closing stage; Determining first duration information of the shutter being in a fully open stage according to the target exposure time and the preset duration information; Acquire a first illuminance at the stage according to a preset sampling frequency, wherein the first illuminance is characterized by the illuminance at the stage at any sampling moment when the shutter is in a fully open stage; A first actual exposure dose accumulated by the stage when the shutter is fully opened is determined according to the first duration information and the first illumination.

2. The method according to claim 1, characterized in that The exposure system further comprises a beam splitter element located in the main light path, the beam splitter element being used to split a detection beam from the main light path; The obtaining of the first light illumination at the stage according to the preset sampling frequency comprises: Collecting a second illuminance of the detection light beam according to the preset sampling frequency, wherein the second illuminance is characterized by the illuminance of the detection light beam at any sampling moment when the shutter is in a fully open stage; The first illumination at the stage is determined according to the second illumination, the transmission-reflection ratio of the beam splitter and the transmittance of the mask.

3. The method according to claim 2, characterized in that The first duration information of the shutter being in the fully open stage determined according to the first exposure dose and the first light illumination includes: The first duration information is determined according to the first dose to be exposed, the first illuminance and an exposure time model, wherein the exposure time model is used to characterize the corresponding relationship between the first dose to be exposed and the first duration information.

4. The method according to claim 3, characterized in that The exposure time model is: Wherein, D is the first exposure dose, K1 is the transmission-reflection ratio of the light splitting element, K2 is the transmittance of the photomask, Δt is the sampling interval, E Bt is the second light illumination, and T is the first duration information.

5. The method according to claim 2, characterized in that The step of determining the first actual exposure dose accumulated by the stage when the shutter is fully opened according to the first duration information and the first illumination comprises: The first actual exposure dose is determined according to the first duration information, the first illuminance and an exposure dose model, wherein the exposure dose model is used to characterize the corresponding relationship between the first duration information and the first actual exposure dose.

6. The method according to claim 5, characterized in that The exposure dose model is: Wherein, D is the first exposure dose, T is the first duration information, and E Bt is the second illumination, Δt is the sampling interval, K1 is the transmission-reflection ratio of the beam splitter, and K2 is the transmittance of the mask.

7. The method according to claim 2, characterized in that The photomask may be placed in the main light path or removed from the main light path. Before acquiring the target information, the method further includes: When the photomask is removed from the main light path, the shutter is controlled to be in a fully open stage, and a first test light illumination at the stage and a second test light illumination of the detection light beam are respectively obtained; The transmission-reflection ratio of the light splitting element is determined according to the first test light illumination and the second test light illumination.

8. The method according to claim 2, characterized in that The photomask may be placed in the main light path or removed from the main light path. Before acquiring the target information, the method further includes: When the photomask is removed from the main light path, controlling the shutter to be in a fully open stage, and obtaining a second test light intensity of the detection light beam; Determine a third test light illumination at the stage according to the transmission-reflection ratio of the beam splitter and the second test light illumination, wherein the third test light illumination is used to characterize the light illumination at the stage when the mask is removed from the main light path and the shutter is in a fully open stage; When the mask plate is located in the main light path, controlling the shutter to be in a fully open stage to obtain a fourth test light illumination at the stage; The transmittance of the photomask is determined according to the third test light illumination and the fourth test light illumination.

9. The method according to claim 1, characterized in that After acquiring the preset duration information of the shutter gradually opening stage and the shutter gradually closing stage, and before determining the first duration information of the shutter being in the fully opening stage according to the target exposure time and the preset duration information, the method further includes: Determine whether the target exposure time is less than or equal to the preset duration information; If yes, then re-acquire the updated target information; If not, continue to determine the first duration information of the shutter being in the fully open stage according to the target exposure time and the preset duration information.

10. An exposure system, characterized in that: The exposure system is controlled by the exposure system control method as described in any one of claims 1 to 9, wherein the exposure system includes a light source, a shutter, a photomask, and a carrier for carrying a wafer, which are arranged in sequence along a main light path, and a light beam of the light source emitted from the shutter is incident on the carrier through the photomask.

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