Pre-examination apparatus and control method thereof

Abstract

The application provides a front-end detection device and a control method thereof. The control method comprises the following steps: after the conveying chamber is vacuumized for a first set time, all air valves are closed, and the vacuum state of the conveying chamber is obtained; then, it is judged whether the vacuum state of the conveying chamber meets a preset condition; if yes, at least one air valve is opened, and the vacuumization of the conveying chamber is continued until the vacuum value of the conveying chamber reaches a wafer vacuum threshold value, then the vacuum conveying valve is allowed to be opened, and the wafer is conveyed from the conveying chamber to the main chamber; wherein the wafer vacuum threshold value is less than or equal to the set vacuum value of the main chamber. Compared with the prior art which judges and controls the threshold value after the vacuumization of the conveying chamber is completed, the control method of the application controls the vacuumization process of the conveying chamber. Therefore, at least the waiting time in the existing vacuumization time can be saved, and even the effective time length in the existing vacuumization time can be shortened, thereby achieving the effect of shortening the wafer front-end detection time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor equipment, in particular to a front-end detection device and a control method thereof. BACKGROUND

[0002] In some application scenarios of front-end detection devices (such as electron beam defect review devices (DR-SEM) and critical dimension measurement equipment (CD-SEM)) for semiconductor manufacturing, the wafer after lithography is detected for defects or measured for critical dimensions in a high-vacuum main chamber. The vacuum degree of the main chamber is one of the important means to determine the defect detection and critical dimension measurement. Currently, some wafers processed by special lithography processes usually perform a vacuum pumping scheme in a fixed delay mode in a load lock before entering the main chamber to promote the release of gas in the photoresist on the wafer, so as to avoid the destruction of the high-vacuum environment of the main chamber by the gas. The vacuum pumping scheme in the fixed delay mode is a scheme for pumping the load lock according to a fixed vacuum pumping time. However, this vacuum pumping scheme has great limitations on wafer front-end detection. For example, the fixed vacuum pumping time (assuming 10 min) is composed of an effective time (e.g., the first 7 min of the 10 min) for releasing gas in the photoresist and a waiting time (e.g., the last 3 min of the 10 min) for redundancy protection. The waiting time is useless for the front-end detection of most wafers, resulting in wasted time and reduced efficiency for wafer front-end detection, and thus causing the throughput of the front-end detection device to be greatly restricted. SUMMARY

[0003] In view of the above problems, the present application is proposed to provide a front-end detection device that overcomes the above problems or at least partially solves the above problems.

[0004] An object of the present application is to solve the problem of wasted wafer front-end detection time caused by the existing vacuum pumping scheme in the fixed delay mode, so as to shorten the wafer front-end detection time.

[0005] Another object of the present application is to improve the accuracy of detecting the vacuum value of the load lock after vacuum pumping, so as to improve the detection accuracy.

[0006] In particular, the present application provides a control method of a front-end inspection apparatus, the front-end inspection apparatus comprising a main chamber for performing wafer inspection, the main chamber being connected to a transfer chamber via a vacuum transfer valve, the vacuum transfer valve being configured to communicate or isolate between the main chamber and the transfer chamber; the transfer chamber being connected to at least one gas valve, at least one of the gas valves being configured to evacuate the transfer chamber; and,

[0007] The control method comprises:

[0008] S100, opening at least one of the gas valves and controlling at least one of the gas pumps to continuously evacuate the transfer chamber for a first set time, when the wafer is in the transfer chamber and the vacuum transfer valve is closed;

[0009] S200, closing all the gas valves and obtaining the vacuum state of the transfer chamber after evacuating the transfer chamber for the first set time;

[0010] S300, determining whether the vacuum state of the transfer chamber meets a preset condition;

[0011] S400, if yes, opening at least one of the gas valves and continuing to evacuate the transfer chamber, and allowing the vacuum transfer valve to be opened and the wafer to be transferred from the transfer chamber to the main chamber after the vacuum value of the transfer chamber reaches a wafer transfer threshold value, wherein the wafer transfer threshold value is less than or equal to a set vacuum value of the main chamber.

[0012] Preferably, in the S200, obtaining the vacuum state of the transfer chamber comprises:

[0013] obtaining a vacuum value of the transfer chamber after a second set time when all the gas valves are closed, denoted as a first vacuum value; and,

[0014] In the S300, the preset condition comprises that the first vacuum value is less than or equal to a first vacuum threshold value, and the first vacuum threshold value is greater than or equal to the wafer transfer threshold value.

[0015] Preferably, in the S200, obtaining the vacuum state of the transfer chamber comprises:

[0016] obtaining a vacuum value of the transfer chamber at a moment when the transfer chamber is evacuated for the first set time, denoted as a second vacuum value;

[0017] obtaining a vacuum value of the transfer chamber after a third set time when all the gas valves are closed, denoted as a third vacuum value;

[0018] calculating a difference between the second vacuum value and the third vacuum value; and,

[0019] In the S300, the preset condition comprises that the difference value is less than or equal to a difference value threshold.

[0020] Preferably, the front-end detection device further comprises a front-end module connected to the transfer chamber via a gate valve, the gate valve being configured to communicate or isolate between the main chamber and the transfer chamber; and,

[0021] After the S300, further comprising:

[0022] If the vacuum state of the transfer chamber does not meet the preset condition, repeating the S100, S200 and S300, and after the number of repetitions reaches a preset number, allowing the gate valve to be opened and the wafer to be returned to the front-end module from the transfer chamber.

[0023] Preferably, the gas valve has two, and the two gas valves are a roughing valve and a gate valve, the roughing valve and the gate valve being arranged in parallel between the air pump and the transfer chamber; and,

[0024] In the case of first execution of the S100, the opening of at least one of the gas valves comprises opening the roughing valve and closing the gate valve; and / or,

[0025] In the case of repeated execution of the S100, the opening of at least one of the gas valves comprises closing the roughing valve and opening the gate valve.

[0026] Preferably, in the S400, the opening of at least one of the gas valves comprises closing the roughing valve and opening the gate valve.

[0027] Preferably, in the case of first execution of the S100, the S100 further comprises:

[0028] Obtaining a vacuum value of the transfer chamber within the first set time, denoted as a fourth vacuum value;

[0029] After the fourth vacuum value is less than or equal to a second vacuum threshold, the roughing valve is closed and the gate valve is opened; wherein the second vacuum threshold is greater than or equal to a wafer vacuum threshold.

[0030] Preferably, before the S100, further comprising:

[0031] According to the preset initial configuration information and / or job configuration information, a target operation mode of the front-end detection device is started; wherein the initial configuration information describes configuration information of the front-end detection device in an initial state, the job configuration information describes configuration information of the front-end detection device in a job state, and the target operation mode is used to make the wafer be transferred to the main chamber after the wafer completes gas release in the transfer chamber.

[0032] Preferably, the wafer transfer threshold is 8E-6 Torr, and the first set time is between 20 seconds and 40 seconds.

[0033] According to another aspect of the present application, a front-end detection device is also provided, comprising:

[0034] A main chamber for wafer detection, the main chamber is connected with a transfer chamber through a vacuum transfer valve, the vacuum transfer valve is configured to be communicated or isolated between the main chamber and the transfer chamber; the transfer chamber is connected with at least one gas valve through at least one gas pump, and the at least one gas pump is configured to pump the transfer chamber to vacuum.

[0035] A control device, the control device is connected with the device body, and a computer program is stored on the control device, the computer program is executed by a processor to realize the steps of the control method.

[0036] In the control method of the present application, the vacuum value of the transfer chamber is judged whether the preset condition is met before the wafer transfer threshold is reached, that is, the vacuum process is judged whether it meets the expectation before the vacuum of the transfer chamber is completed, so that the vacuum process is controlled according to the judgment result. Compared with the threshold judgment and control after the vacuum of the transfer chamber is completed in the prior art, the control method of the present application realizes the control of the vacuum process of the transfer chamber. According to the control of the vacuum process of the transfer chamber, the control method of the present application can discover the wafer gas release condition earlier, and can also make a decision on the vacuum strategy suitable for the wafer earlier. For example, in the case that the vacuum state of the transfer chamber meets the preset condition, the control method of the present application can judge that the wafer gas release time is short, so there is no need to wait for the existing vacuum time, and the wafer can complete the gas release, thereby at least the waiting time in the existing vacuum time can be saved, and even the effective time length in the existing vacuum time can be shortened, thereby solving the problem that the wafer front-end detection time is wasted caused by the existing fixed task execution mode vacuum scheme, and realizing the effect of shortening the wafer front-end detection time.

[0037] Further, in the control method of the present application, by closing all gas valves and waiting for the second set time or the third set time, the wafer is allowed to release gas in a vacuum state and in a closed transfer chamber, so as to prolong the time length of the wafer releasing gas in the vacuum state, thereby improving the influence of the wafer releasing gas on the vacuum state in the transfer chamber, and making the vacuum value measurement result of the transfer chamber more accurately reflect the wafer releasing gas, and further improving the accuracy of the vacuum value detection of the transfer chamber after vacuumizing, so as to achieve the purpose of improving the detection precision.

[0038] The above and other objects, advantages and features of the present application will become more apparent from the following detailed description of specific embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0039] Some specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. The same reference numbers in different drawings denote the same or similar components or parts. It should be understood by those skilled in the art that the drawings are not necessarily drawn to scale. In the drawings:

[0040] Figure 1 is a schematic diagram of the main components of the existing front-end detection equipment;

[0041] Figure 2 is a schematic diagram of the principle of the front-end detection equipment according to an embodiment of the present application;

[0042] Figure 3 is a flowchart of the control method according to an embodiment of the present application when the vacuum state meets the preset condition;

[0043] Figure 4 is a flowchart of the control method according to an embodiment of the present application;

[0044] Figure 5 is a flowchart of the control method according to an embodiment of the present application when the first vacuum value is used for judgment;

[0045] Figure 6 is a flowchart of the control method according to an embodiment of the present application when the difference is used for judgment.

[0046] Wherein: front-end module-10, transfer chamber-20, main chamber-30, gate valve-40, vacuum transfer valve-50, wafer-60, gas valve-70, roughing valve 71, gate valve 72, main chamber electronic valve 73, main chamber electronic valve 73 and transfer chamber solenoid valve-74, main chamber molecular pump-81, transfer chamber molecular pump-82, dry pump-83. DETAILED DESCRIPTION

[0047] In the semiconductor chip production process, lithography is the foundation and the most important link. The photoresist used in lithography is a compound composed of a soluble compound and a photosensitive material. Not only in lithography, photoresist in lithography will undergo chemical reactions such as degradation, fusion in solvents, and release gas under conditions such as heating, light, and atomic bombardment; moreover, within a certain period of time after lithography, the wafer will continue to release gas. These wafers will usually enter the front-end detection equipment such as electron beam defect review equipment (DR-SEM) and critical dimension measurement equipment (CD-SEM) for front-end detection of wafers in a high-vacuum environment. However, the continuous release of gas from the wafer will destroy the high-vacuum environment in the front-end detection equipment, causing the front-end detection equipment to shut down, reducing the normal operating time (UP time) of the front-end detection equipment, and even reducing the yield of semiconductor chips.

[0048] Figure 1 The main components of the existing front-end detection equipment are shown. Referring to Figure 1 , the existing front-end detection equipment mainly consists of a front-end module 10 (EFEM), a transfer chamber 20 (Load Lock), and a main chamber 30 (Main Chamber). The wafer is transferred to the transfer chamber 20 by an external transmission mechanism in the front-end module 10; then, the transfer chamber 20 is evacuated; then, after the vacuum value of the transfer chamber 20 reaches the set threshold (<5E-6 Torr), the wafer is transferred to the main chamber 30 by an internal transmission mechanism; finally, in the main chamber 30, the wafer is subjected to defect review, critical dimension measurement, and other work. However, wafers processed by special lithography will have a long-term outgassing phenomenon (Outgassing Wafer). If such wafers are transported by the external transmission mechanism to the transfer chamber, and the transfer chamber molecular pump 82 matched with the transfer chamber 20 is started to evacuate the transfer chamber 20 according to the normal wafer transmission process; then, the wafer is transferred to the main chamber 30, and the wafer is still continuously outgassing at this time. The gas released by the wafer will destroy the vacuum state of the main chamber 30, causing the front-end detection equipment to shut down.

[0049] To solve the above problems, the existing technology proposes a vacuum evacuation scheme of a fixed delay task execution mode (Fix Delay), which includes:

[0050] 1. After the wafer is transferred to the transfer chamber, the gate valve is closed, the roughing valve is opened, and the dry pump 83 is used to evacuate the transfer chamber;

[0051] 2. When the vacuum value in the transfer chamber reaches 5E-2 Torr, the roughing valve is closed, the gate valve is opened, and the transfer chamber molecular pump 82 is used to evacuate;

[0052] 3. When the transfer chamber vacuum reaches a first vacuum threshold (i.e. a transfer wafer threshold, typically 8E-6 Torr), the wafer is transferred to the main chamber 30 by the internal transfer mechanism.

[0053] wherein a fixed evacuation time (e.g. 10 minutes) is set for the transfer chamber, at the time when the evacuation time is reached, the vacuum value of the transfer chamber is detected. If the vacuum value is less than or equal to a set threshold, the wafer is transferred to the main chamber 30 by the internal transfer mechanism. If the vacuum value is greater than the set threshold, the transfer chamber is vented to ambient atmospheric pressure (Vent LoadLock), and then the wafer is transferred to an EFEM FOUP in the front end module 10 by the external transfer mechanism; or, if the vacuum value is greater than the set threshold, the evacuation of the transfer chamber is continued until the vacuum value is less than or equal to the set threshold, and then the wafer is transferred to the main chamber 30.

[0054] However, for the front-end detection equipment, in addition to the detection accuracy of the wafer, the throughput is also a crucial indicator. At present, according to artificial experience, the evacuation time set for the transfer chamber is usually greater than the continuous outgassing time of the wafer (or there is still a small amount of outgassing but it will not affect the detection in the main chamber 30), for example, the evacuation time usually set is 10 min, and the continuous outgassing time of the wafer is 7 min, so that 3 min of waiting time will be caused, which causes the preparation time before the wafer detection to be too long, and reduces the number of wafers that can be detected on the front-end detection equipment per unit time, that is, reduces the throughput of the front-end detection equipment.

[0055] In yet some prior art, some special photolithography processes can cause the wafer to outgas for a long time. Usually for this case, the pumping speed of the evacuation pump is greater than the outgassing rate of the wafer, and although the vacuum value inside the transfer chamber continues to decrease, the wafer is still continuously outgassing. If the evacuation scheme in the time task execution mode is adopted, after the evacuation time is completed, although the vacuum value inside the transfer chamber meets the transfer wafer threshold (i.e. the vacuum value at which the wafer can be transferred from the transfer chamber to the main chamber 30) in a short time, the wafer is still in a continuous outgassing state, and once the wafer enters the main chamber 30 by the internal transfer mechanism, the high vacuum environment of the main chamber 30 will be destroyed, and the front-end detection equipment will be down.

[0056] In order to at least solve the problem that the wafer front-end detection time is wasted caused by the evacuation scheme in the time task execution mode in the prior art, an embodiment of the present application proposes a control method for a front-end detection equipment.

[0057] Figure 2 A schematic diagram of a front-end detection equipment according to an embodiment of the present application is shown. Referring to the schematic diagram, the front-end detection equipment comprises a transfer chamber 20, a main chamber 30, an internal transfer mechanism 40, an external transfer mechanism 50, and a control system 60. Figure 2The front-end detection device in one embodiment of the present application also mainly consists of the front-end module 10, the transfer chamber 20 and the main chamber 30. A door valve 40 is arranged between the front-end module 10 and the transfer chamber 20, and the door valve 40 is configured to control the communication and interruption between the front-end module 10 and the transfer chamber 20. A vacuum transfer valve 50 is arranged between the transfer chamber 20 and the main chamber 30, and the vacuum transfer valve 50 is configured to control the communication and interruption between the transfer chamber 20 and the main chamber 30. In addition, the transfer chamber 20 is connected to at least one air pump through at least one air valve 70, and the air pump is configured to pump the transfer chamber 20 to vacuum.

[0058] In some preferred embodiments of the present application, as shown in Figure 2 The air valve 70 has a plurality of air valves 70, one of which is a roughing valve 71 and the other of which is a gate valve 72. The roughing valve 71 and the gate valve 72 are arranged in parallel between the air pump and the transfer chamber 20, so that the air pump can communicate with the transfer chamber 20 when either the roughing valve 71 or the gate valve 72 is open. The roughing valve 71 and the gate valve 72 belong to the commonly used valves in the vacuum system in the field of semiconductor manufacturing, and the main difference between them is that the roughing valve 71 has relatively poor machining precision, so that the roughing valve 71 is often used for flow and pressure control in the low-precision control stage; while the gate valve 72 is often used for control in the high-precision control stage.

[0059] In some preferred embodiments of the present application, the air pump has three air pumps, which are a main chamber molecular pump 81, a transfer chamber molecular pump 82 and a dry pump 83. The inlet of the main chamber molecular pump 81 is connected to the main chamber 30, and the outlet of the main chamber molecular pump 81 is connected to the dry pump 83 through a main chamber electronic valve 73. The inlet of the transfer chamber molecular pump 82 is connected to the transfer chamber 20 through the gate valve 72, and the outlet of the transfer chamber molecular pump 82 is connected to the dry pump 83 through a transfer chamber solenoid valve 74. The inlet of the dry pump 83 is connected to three parallel air pumping branches, which include a main chamber pumping branch formed by the main chamber electronic valve 73 and the main chamber molecular pump 81 in series, a first transfer chamber pumping branch formed by the roughing valve 71, and a second transfer chamber pumping branch formed by the gate valve 72, the transfer chamber molecular pump 82 and the transfer chamber. In addition, the main chamber electronic valve 73 and the transfer chamber solenoid valve 74 are both Turbo brand solenoid pulse valves, and both the main chamber electronic valve 73 and the transfer chamber solenoid valve 74 are in the normally open state.

[0060] Figure 3 A flowchart of a control method according to one embodiment of the present application is shown. Based on the Figure 3 , and referring to Figure 2 and Figure 4 It can be seen that in one embodiment of the present application, the control method for the front-end detection device of the present application comprises:

[0061] S100, with the wafer 60 inside the transfer chamber 20 and the vacuum transfer valve 50 closed, at least one gas valve 70 is opened, and the vacuum pump is controlled to continuously evacuate the transfer chamber 20 for a first set time.

[0062] The scenario where wafer 60 is inside transfer chamber 20 and vacuum transfer valve 50 is closed typically refers to the situation where, after wafer 60 enters transfer chamber 20 from front-end module 10, both gate valve 40 and vacuum transfer valve 50 are closed. In this case, transfer chamber 20 is sealed by gate valve 40 and vacuum transfer valve 50, and all gas released from wafer 60 will reside within transfer chamber 20. Of course, in some existing technologies, the purpose of evacuating transfer chamber 20 is to ensure that the vacuum value of transfer chamber 20 matches that of main chamber 30, thereby using transfer chamber 20 as an isolation buffer chamber to ensure that the vacuum value of main chamber 30 remains at the set vacuum value. However, in the control method of this invention, in addition to evacuating transfer chamber for the aforementioned purpose, ensuring that all or most of the gas released from wafer 60 is processed within transfer chamber 20 is also a very important objective; otherwise, continued gas release from wafer 60 within main chamber 30 will have a detrimental effect on wafer 60 detection.

[0063] The vacuum transfer valve 50 is typically mounted on the housing of the transfer chamber. It is configured to connect the transfer chamber and the main chamber 30 to maintain them at the same pressure, or to disconnect the connection between the transfer chamber and the main chamber 30 to maintain a vacuum in the transfer chamber. The gate valve 40 is typically mounted on the housing of the transfer chamber. It is configured to connect the external atmospheric pressure environment and the transfer chamber to maintain them at the same pressure, or to disconnect the connection between the external atmospheric pressure environment and the transfer chamber to maintain a vacuum in the transfer chamber.

[0064] In this embodiment, the air valve specifically refers to the valve located between the suction pump and the transfer chamber 20, which controls the flow of air between them. When there is only one air valve 70, its own opening and closing is sufficient to control the flow between the suction pump and the transfer chamber 20. However, when there are two or more air valves 70 (for example, in some embodiments of the present invention, there are two air valves 70, namely a coarse suction valve 71 and a gate valve 72), the two or more air valves 70 can be connected in series, in parallel, or in a combination of series and parallel. Especially when the combination of two or more air valves 70 includes a parallel connection, the connection between the suction pump and the transfer chamber can be achieved by connecting any air valve 70 on any parallel branch; however, the connection between the suction pump and the transfer chamber can only be cut off when at least one air valve 70 on all parallel branches is closed.

[0065] The first set time can be a preset fixed time value, such as 30 seconds; or it can be a time value calculated based on specific conditions, such as a variable time value set according to the photolithography process of wafer 60. Of course, regardless of how the first set time is selected, it is usually shorter than the time it takes for the wafer to release gas. For example, if it takes 7 minutes for the wafer to release gas, then the first set time can be within the range of 7 minutes; or, for example, the first set time can be set to 30 seconds. How to determine the time it takes for wafer 60 to release gas after ordinary photolithography is irrelevant to the control method of this invention and is considered prior art. For example, the time for the wafer to release gas can be obtained by sampling and analyzing the wafer after photolithography; or, the time for the wafer to release gas after photolithography can be directly analyzed based on the composition of the photoresist.

[0066] S200: After the vacuum chamber 20 is evacuated for the first set time, all air valves 70 are closed, and the vacuum state of the transfer chamber 20 is obtained.

[0067] After the transfer chamber 20 is evacuated for a first set time, the state of the wafer 60 inside the transfer chamber 20 can be one of two possibilities: either it has been completely or substantially degassed, or it is still releasing a large amount of gas. To facilitate the explanation and illustration of the control method of the present invention based on these two different states of the wafer 60, we can define the former as a normal wafer and the latter as a long-term degassed wafer.

[0068] As mentioned earlier, after the initial vacuum period, the ordinary wafer has finished or substantially finished releasing gas within the transfer chamber 20. Therefore, after closing all gas valves 70, the vacuum state of the transfer chamber 20 will remain or substantially remain the same as before closing all gas valves 70. In other words, the vacuum value of the transfer chamber 20 is consistent or substantially consistent before and after closing all gas valves 70. Thus, this step S200 enables the transfer chamber to achieve a vacuum state that is close to or directly equal to the wafer transfer vacuum threshold.

[0069] In some cases, the length of the first set time can be appropriately shorter. This way, although the ordinary wafer may not have completed or substantially completed gas release, it's possible to determine whether the wafer is an ordinary wafer or a long-term venting wafer based on the gas release after the first set time. In this case, the length of the first set time will achieve an effect essentially consistent with the aforementioned time setting method. In other cases, as long as the first set time is set short enough, although the ordinary wafer may not complete or substantially complete gas release in a single first set time, it will eventually complete or substantially complete gas release after multiple repetitions.

[0070] As can be seen from the above, as long as the length of the first set time is less than the length of time that a normal wafer continuously releases gas, the wafer type can be determined before the vacuum threshold of the transfer chamber 20 is reached, thus eliminating the waiting time in the existing vacuuming time.

[0071] The vacuum state reflects the impact of the gas released by wafer 60 within the sealed transfer chamber 20 on the vacuum value after a first set time. With the transfer chamber 20 closed, the gas released by wafer 60 is a determining factor affecting the vacuum value of the transfer chamber 20; therefore, this vacuum state is an important means of determining whether wafer 60 is a standard wafer. If wafer 60 is a standard wafer, it will release less gas after the first set time, and the impact on the vacuum value will be insignificant; conversely, if it is a long-term venting type wafer, it will release more gas, and the impact on the vacuum value will be more significant.

[0072] S300, determine whether the vacuum state of the transfer chamber 20 meets the preset conditions.

[0073] In step S300, determining whether the vacuum state meets the preset conditions can indirectly determine the type of wafer 60 in the transfer chamber 20 (i.e., a normal wafer or a long-term venting wafer), allowing for more targeted decisions regarding subsequent steps of the control method of this invention. For example, if the vacuum state meets the preset conditions, we can determine that the wafer 60 in the transfer chamber 20 is a normal wafer. In subsequent steps, a shorter period of vacuuming will be performed, similar to the gas release time for a normal wafer, before transferring the wafer to the main chamber 30. Conversely, if the wafer 60 in the transfer chamber 20 is determined to be a long-term venting wafer, depending on the required gas release time, selective evacuation will continue or the wafer will be directly returned to the front-end module 10.

[0074] Of course, the preset conditions will vary depending on the state of the transfer chamber 20 as reflected by the vacuum state. For example, if the vacuum state indicates that the ordinary wafer in the transfer chamber 20 can completely or almost completely release gas, the preset conditions will be required according to the vacuum value of the transfer chamber 20 reaching or approaching the wafer transfer vacuum threshold; if the vacuum state indicates that the ordinary wafer in the transfer chamber 20 is still in a degassing state, the preset conditions will be required according to the influence of the ordinary wafer on the vacuum state of the transfer chamber 20 under the corresponding conditions.

[0075] S400, when the vacuum state of the transfer chamber 20 meets the preset conditions, at least one gas valve 70 is opened, and the transfer chamber 20 is evacuated until the vacuum value of the transfer chamber 20 reaches the wafer transfer vacuum threshold. Then, the vacuum transfer valve 50 is allowed to be opened and the wafer 60 is transferred from the transfer chamber 20 to the main chamber 30. The wafer transfer vacuum threshold is less than or equal to the set vacuum value of the main chamber 30.

[0076] In this embodiment, the fact that the vacuum state of the transfer chamber 20 meets the preset conditions reflects that the wafer 60 inside the transfer chamber 20 is a normal wafer. Based on this, we can conclude that after the transfer chamber 20 is evacuated to the wafer transfer vacuum threshold, the wafer 60 will stop or almost stop releasing gas. After the wafer 60 is transferred to the main chamber 30, the wafer 60 will not or almost will not affect the high vacuum conditions of the main chamber 30, and the inspection operation of the wafer 60 can be completed normally.

[0077] The wafer transfer vacuum threshold is typically used as an important indicator to determine whether the vacuum value in the transfer chamber 20 is consistent with that in the main chamber 30. That is, once the vacuum value in the transfer chamber 20 reaches the wafer transfer vacuum threshold, under normal circumstances (e.g., for a wafer 60 that does not release gas), the wafer 60 is allowed to be transferred from the transfer chamber 20 to the main chamber 30. Of course, the set vacuum value of the main chamber 30 refers to the vacuum value that the main chamber 30 normally maintains, and is also the vacuum value required to maintain high vacuum conditions during normal testing operations.

[0078] In this embodiment, the control method of the present invention evaluates the vacuum state of the transfer chamber 20 using preset conditions before the vacuum threshold for wafer transfer is reached, thus realizing a strategy for process control of vacuuming the transfer chamber 20 according to the type of wafer 60. Compared with the result control strategy of existing vacuum control, the control method of the present invention can flexibly adjust the vacuuming time of the transfer chamber 20 according to the type of wafer 60. Especially when the wafer 60 is a common wafer, it can save at least the waiting time in the existing vacuuming time. At the same time, if the wafer type can be determined earlier, sufficient time will be given to adjust the subsequent steps of wafer processing. For example, if it is determined that the wafer is a long-term venting type wafer, the processing time of this type of long-term venting type wafer can be further shortened by increasing the pumping speed of the vacuum pump, increasing the opening of the gas valve, and sending it back to the front-end module 10.

[0079] Figure 4 A schematic flowchart of a control method according to an embodiment of the present invention is shown. (Refer to...) Figure 4 As shown, in some embodiments of the present invention, after S300, the following step is further included:

[0080] S500, if the vacuum state of the transfer chamber 20 does not meet the preset conditions, repeat S100, S200 and S300, and after the number of repetitions reaches the preset number, allow the gate valve 40 to be opened and return the wafer 60 from the transfer chamber 20 to the front-end module 10.

[0081] First, for ease of explanation and description of the control method of the present invention, we can collectively refer to the execution of S100, S200, and S300 in this embodiment as the execution of the target steps. This embodiment illustrates that in some cases, the processing of wafer 60 can be completed by repeatedly executing the target steps. For example, if the length of the first set time is set too short, and the first execution of the target step, or even several repetitions of the target step, fails to achieve the preset vacuum state of the transfer chamber 20, then the target steps are repeated to compensate for the inappropriate value of the first set time. As another example, if the type of wafer 60 is between a standard wafer and a long-term venting type wafer, and executing the target step once, or even a few repetitions, fails to achieve the preset vacuum state of the transfer chamber 20, then the control method of the present invention can only be applied to this type of wafer 60 by increasing the number of repetitions of the target steps.

[0082] However, the gas release time for long-term venting wafers is relatively long. If the control method of this invention is extended to include long-term venting wafers as well, a small number of long-term venting wafers would occupy the transfer chamber 20 for an extended period, while a large number of wafers 60 to be processed would accumulate in the front-end module 10, and the main chamber 30 would be idle for a considerable time. Therefore, to avoid the long-term occupation of the transfer chamber by these long-term venting wafers, this embodiment proposes a method of limiting the maximum number of repetitions of the target step, i.e., a preset number of repetitions. This allows long-term venting wafers that cannot complete venting after multiple repetitions to be returned to the front-end module 10, ending their processing in the transfer chamber 20. In this way, the processing space in the transfer chamber 20 can be freed up, and the high vacuum conditions caused by long-term venting wafers entering the main chamber 30 can be avoided.

[0083] For example, if the preset number of times is set to 10, and the vacuum state of the transfer chamber 20 still does not meet the preset condition after the first 9 executions of the target step, the control method of the present invention will continue to execute the target step in a loop; until the target step is still not met after the 10th execution, the control method of the present invention will terminate the loop and directly return the wafer 60 to the front-end module 10 (usually to the wafer 60 box of the front-end module 10).

[0084] Figure 5A flowchart illustrating the determination based on a first vacuum value is shown in one embodiment of the present invention. Based on this... Figure 5 As shown, in S200, the vacuum state of the transfer chamber 20 is obtained, including obtaining the vacuum value of the transfer chamber 20 after a second set time after all air valves 70 are closed, which is denoted as the first vacuum value.

[0085] Within the second set time period, the wafer 60 can release a detectable amount of gas under vacuum conditions. Specifically, during the first set time period before the second set time, a vacuum pump evacuates the transfer chamber 20. Especially when the wafer 60 in the transfer chamber 20 is a standard wafer, the vacuum value of the transfer chamber 20 may reach the wafer transfer vacuum threshold after the first set time. Thus, with all gas valves 70 closed, the gas released by the wafer 60 will be the main factor affecting the vacuum value of the transfer chamber 20. Therefore, the longer the second set time, the higher the vacuum value of the transfer chamber 20 will be if the wafer 60 is still releasing gas, indirectly indicating that the wafer 60 is a long-term venting type wafer. Conversely, if the wafer has finished or basically finished releasing gas, even if the second set time is long, the vacuum value of the transfer chamber 20 will not change or will only increase slightly. Therefore, by observing the change in the vacuum state within the second set time, the type of wafer can be conveniently and indirectly determined. At the same time, to reduce the impact of the length of the second set time on the preparation time before the front-end inspection of the wafer 60, the second set time can be as short as possible. For example, if the first set time is 30 seconds, the second set time can be 10 seconds or 15 seconds.

[0086] In S300, the preset conditions include a first vacuum value less than or equal to a first vacuum threshold, and a first vacuum threshold greater than or equal to a transfer vacuum threshold.

[0087] This embodiment provides a scheme for determining the result after a first set time using absolute values. Specifically, based on the preferred embodiment given in this embodiment, the control method of the present invention includes:

[0088] S100, when the wafer is in the transfer chamber and the vacuum transfer valve is closed, open at least one of the gas valves and control the vacuum pump to continuously evacuate the transfer chamber for a first set time.

[0089] S210, after the vacuum chamber is evacuated for the first set time, all the gas valves are closed, and the vacuum value of the transfer chamber is obtained after a second set time of closing all the gas valves, which is recorded as the first vacuum value.

[0090] S310, determine whether the first vacuum value is less than or equal to the first vacuum threshold;

[0091] S400, if the condition is met (i.e. less than or equal to), then at least one of the gas valves is opened, and the transfer chamber is evacuated until the vacuum value of the transfer chamber reaches the wafer transfer vacuum threshold. Then, the vacuum transfer valve is allowed to be opened and the wafer is transferred from the transfer chamber to the main chamber; wherein the wafer transfer vacuum threshold is less than or equal to the set vacuum value of the main chamber.

[0092] Therefore, this embodiment determines whether the vacuum state meets preset conditions by comparing absolute values; specifically, it compares the second vacuum value and the second vacuum threshold. On the one hand, this comparison method is easy to implement, reducing the difficulty of determining the wafer type (e.g., type 60). On the other hand, the value of the second vacuum threshold being greater than or equal to the wafer transfer vacuum threshold can be divided into two cases. First, when the second vacuum threshold is equal to the wafer transfer vacuum threshold, the gas released by the wafer 60 will have a more significant impact on the vacuum conditions in the transfer chamber, and it will be easier to quickly determine the type of the wafer 60. Correspondingly, the value of the second set time can be shortened. Second, when the second vacuum threshold is greater than the wafer transfer vacuum threshold, more gas can be released by the wafer 60 within the same second set time. This means that the requirements for the wafer 60 can be relaxed, and it can be applied to the pre-test preparation of the wafer 60 when there is still a small amount of gas released in the main chamber 30. At the same time, the second case can be applied to the stage when the wafer 60 is still in the stage of large-scale gas release, which means that the length of the first set time can be shortened (the shorter the first set time, the shorter the gas release time of the wafer 60), thereby further shortening the pre-test preparation time of the wafer 60.

[0093] Figure 6 A schematic flowchart illustrating the judgment based on the difference in a control method according to an embodiment of the present invention is shown. (Refer to...) Figure 6 As shown, in some embodiments of the control method of the present invention, in S200, obtaining the vacuum state of the transfer chamber includes:

[0094] When the vacuum in the transmission chamber reaches the first set time, the vacuum value of the transmission chamber is obtained and recorded as the second vacuum value.

[0095] The vacuum value of the transfer chamber is obtained after a third set time when all air valves are closed, and is recorded as the third vacuum value;

[0096] Calculate the difference between the second and third vacuum values.

[0097] The second vacuum value can be obtained before, after, or during the closing of all gas valves 70. Preferably, it is obtained before closing all gas valves 70, as the vacuum value in the transfer chamber 20 is the lowest among these three scenarios, maximizing the difference in this embodiment. This second vacuum value reflects the vacuum value in the transfer chamber at the end of the first set time. If wafer 60 is a standard wafer, the gas released by wafer 60 during the subsequent third set time will have a small, or even no, impact on the second vacuum value, resulting in the smallest difference. Conversely, if wafer 60 is a long-term venting type wafer, the gas released by wafer 60 will have a significant impact on the second vacuum value, resulting in the largest difference.

[0098] The third set time can be the same as or different from the second set time, but both are intended to allow the wafer 60 to release the detected amount of gas under vacuum conditions. Compared to the prior art where vacuum values ​​are obtained instantaneously at the end of the vacuuming time or during the vacuuming period, this embodiment extends the settling time of the transfer chamber in a closed state, making the impact of the gas released by the wafer 60 on the vacuum conditions of the transfer chamber more significant and easier to measure. Simultaneously, to reduce the impact of the length of the third set time on the pre-processing time of the wafer 60 for front-end inspection, this third set time can also be as short as possible. For example, if the first set time is 30 seconds, the third set time can be 10 seconds or 15 seconds.

[0099] Where the third set time and the second set time are the same, the third vacuum value and the first vacuum value should also be the same. Both the third and first vacuum values ​​reflect the vacuum value of the transfer chamber 20 under the influence of wafer 60 after all gas valves have been closed for a period of time under vacuum conditions. Unlike the above embodiment where the first vacuum value is used for absolute comparison, in this embodiment, the third vacuum value is calculated together with the second vacuum value for relative comparison. Of course, in this embodiment, the difference = second vacuum value - third vacuum value, so normally, this difference should be a negative value. For example, if the second vacuum value is 8E-6 Torr, the vacuum value of the transfer chamber 20 will increase during the third set time due to the influence of wafer 60; for example, if the third vacuum value is 8E-5 Torr, the difference will be -7.2E-5 Torr.

[0100] In S300, the preset conditions include the difference being less than or equal to the difference threshold.

[0101] This embodiment provides a scheme for determining the result after a first set time using relative values. Specifically, based on the preferred embodiment given in this embodiment, the control method of the present invention includes:

[0102] S100, when the wafer is in the transfer chamber and the vacuum transfer valve is closed, open at least one of the gas valves and control the vacuum pump to continuously evacuate the transfer chamber for a first set time.

[0103] S220a, in response to the moment when the vacuum of the transfer chamber reaches the first set time, the vacuum value of the transfer chamber is obtained and recorded as the second vacuum value;

[0104] S220b, obtain the vacuum value of the transfer chamber after a third set time when all air valves are closed, and record it as the third vacuum value;

[0105] S220c, calculate the difference between the second and third vacuum values;

[0106] S320, determine whether the difference is less than or equal to the difference threshold;

[0107] S400, if the condition is met (i.e. less than or equal to), then at least one of the gas valves is opened, and the transfer chamber is evacuated until the vacuum value of the transfer chamber reaches the wafer transfer vacuum threshold. Then, the vacuum transfer valve is allowed to be opened and the wafer is transferred from the transfer chamber to the main chamber; wherein the wafer transfer vacuum threshold is less than or equal to the set vacuum value of the main chamber.

[0108] Therefore, this embodiment, as an alternative to the above embodiment that uses the first vacuum value for absolute value judgment, differs mainly in that it uses difference comparison to determine whether the vacuum state meets the preset conditions. For example, when the second vacuum value is 8E-6 Torr, affected by the wafer 60, the vacuum value of the transfer chamber 20 will increase within the third set time, for example, when the third vacuum value is 8E-5 Torr, the difference will be -7.2E-5 Torr. Correspondingly, when the difference threshold is set to -7.2E-5 Torr, we can find that the difference between the second and third vacuum values ​​is exactly equal to the difference threshold, and thus we can conclude that the vacuum state of the transfer chamber 20 meets the preset conditions. Compared to the above embodiment that judges based on the first vacuum value after the second set time, this embodiment uses the difference between the vacuum values ​​(i.e., the second and third vacuum values) corresponding to the beginning and end of the third set time for judgment. This difference directly reflects the change in the vacuum state within the transfer chamber 20 within the third set time, especially when the second vacuum value is smaller, the difference will be more obvious. Therefore, it is easier to determine the type of wafer in the absolute value judgment compared to wafers with long-term venting. For ordinary wafers, the gas released by wafer 60 within the third set time has little impact on the second vacuum value. The judgment method of this embodiment is more applicable and can further improve the accuracy of wafer 60 type determination. This also improves the accuracy of vacuum value detection in the transfer chamber after vacuuming, thereby enabling more accurate venting treatment before wafer 60 detection. It also saves time for vacuuming the transfer chamber 20 to a certain extent and improves the accuracy of wafer 60 detection.

[0109] like Figure 2 As shown, in some embodiments of the control method of the present invention, in the first execution of S100, opening at least one air valve includes opening a coarse extraction valve and closing a gate valve; and / or,

[0110] When S100 is executed repeatedly, opening at least one air valve includes closing the coarse extraction valve and opening the gate valve.

[0111] This embodiment provides at least three different combinations of the two types of air valves 70 during the execution of the target step, namely:

[0112] The first method is to use the coarse extraction valve 71 when performing the target step for the first time. When performing the target step thereafter, the coarse extraction valve 71 can be used alone, the gate valve 72 can be used alone, or the coarse extraction valve 71 and the gate valve 72 can be used in combination.

[0113] The second option is to use the roughing valve 71 alone, the gate valve 72 alone, or the combination of the roughing valve 71 and the gate valve 72 when performing the departmental target steps for the first time. Then, the gate valve 72 is used when performing the target steps thereafter.

[0114] The third method involves using the coarse extraction valve 71 during the first execution of the target step, and then using the gate valve 72 during subsequent executions of the target step.

[0115] Based on the different characteristics exhibited by the coarse extraction valve 71 and the gate valve 72 in the vacuum system, the first combination method is suitable for working scenarios where valve precision requirements are not high. The second combination method is suitable for working scenarios where initial coarse / precise control is followed by precise control. The third combination method differs from the second in that, during the initial execution, only coarse control can be selected. These different combinations of the coarse extraction valve 71 and the gate valve 72 also correspond to different wafers 60. That is, if the outgassing of wafer 60 is not severe, coarse control is sufficient. However, if the outgassing of wafer 60 is severe, the degree of precise control can be increased as appropriate. Therefore, for ordinary wafers with less outgassing, the frequency of use of the coarse extraction valve 71 can be increased in this embodiment to achieve low-cost control. For wafers with relatively more long-term outgassing, the frequency of use of the gate valve 72 can be increased in this embodiment to improve the airtightness of the vacuum pipeline to a certain extent and accelerate the vacuuming efficiency.

[0116] In some embodiments of the present invention, in S400, opening at least one of the air valves includes closing the coarse extraction valve and opening the gate valve.

[0117] In this embodiment, based on the characteristics of the coarse extraction valve 71 and the gate valve 72, after determining the type of wafer 60, this embodiment uses the gate valve 72 to perform vacuuming, which can achieve precise control in the final vacuuming stage, speed up the vacuuming process, thereby shortening the preparation time of wafer 60 in the transfer chamber 20, and improving the yield of semiconductor chip manufacturing to a certain extent.

[0118] In some embodiments of the present invention, when S100 is executed for the first time, S100 further includes:

[0119] The vacuum value of the teleportation chamber within the first set time (i.e., under the condition that the teleportation chamber is continuously evacuated) is obtained and recorded as the fourth vacuum value.

[0120] After the fourth vacuum value is less than or equal to the second vacuum threshold, the coarse pumping valve is closed and the gate valve is opened; wherein the second vacuum threshold is greater than or equal to the transfer vacuum threshold.

[0121] In this embodiment, the operation of opening the coarse extraction valve 71 and closing the gate valve 72 during the first execution of the target step results in lower control costs and faster response speed in the initial stage of vacuuming the transfer chamber 20. Subsequently, the operation of closing the coarse extraction valve 71 and opening the gate valve 72 represents a switch from the coarse extraction valve 71 to the gate valve 72, achieving a combination of coarse control in the early stage and precise control in the later stage. The switching from coarse to precise control is based on the vacuum value (i.e., the fourth vacuum value) of the transfer chamber 20 reaching the second vacuum threshold (preferably, this second vacuum threshold is greater than the transfer vacuum threshold; for example, if the transfer vacuum threshold is 8E-6 Torr, the second vacuum threshold is typically 5E-6 Torr). This balances the economic advantages of the coarse extraction valve 71 and the precision of the gate valve 72, making the process control of vacuuming the transfer chamber 20 more reasonable and efficient.

[0122] In some embodiments of the present invention, the method further includes the following step before S100:

[0123] Based on the preset initial configuration information and / or job configuration information, the target working mode of the front-end inspection equipment is activated; wherein, the initial configuration information describes the configuration information of the front-end inspection equipment in the initial state, the job configuration information describes the configuration information of the front-end inspection equipment in the job state, and the target working mode is used to enable the wafer to be transferred to the main chamber after the gas is released in the transfer chamber.

[0124] The target operating mode describes the switching control strategy used by the front-end inspection equipment when processing vented wafers 60. Compared to front-end inspection equipment without this target operating mode or with it turned off, this target operating mode offers both high efficiency and reliability in vacuum control for ordinary wafers. Of course, even when this target operating mode is turned off, the front-end inspection equipment can still operate in other modes. For example, it can run a vacuum scheme based on existing timed task execution, or it can run a vacuum scheme for non-vented wafers.

[0125] The initial configuration information describes the relevant configurations made during the initial setup of the front-end inspection equipment of this invention (e.g., factory setup, debugging setup). For example, during factory setup, the user selects to turn the target operating mode on or off according to their needs. The operation configuration information can be based on the conditions of the front-end inspection equipment itself, such as the operating parameters of the front-end inspection equipment and its position in the semiconductor manufacturing front-end equipment; it can also be based on the wafer 60, such as the temperature of the wafer 60, the photolithography parameters, the type of photoresist, and whether it has been photolithographically processed or whether there is any venting.

[0126] This embodiment demonstrates that, in addition to the target operating mode, the control method of the present invention can also include other operating modes. Thus, even when the target operating mode is initially disabled, or disabled according to job configuration information, other operating modes may also require evacuating the transfer cavity 20. For example, to achieve wafer transfer with consistent pressure in the transfer cavity 20 and the main chamber 30, the wafer 60 is directly sent into the main chamber 30 after the transfer cavity 20 is evacuated. These other operating modes are more suitable for wafers 60 that have not undergone photolithography or have not released gas after photolithography. Especially when using these other operating modes, at least one step of determining the wafer type 60 is eliminated, thereby further reducing the processing time for wafer 60 preparation before inspection in the transfer chamber and improving the yield of semiconductor chip manufacturing to a certain extent.

[0127] In some embodiments of the present invention, the transfer vacuum threshold is 8E-6 Torr, and the first set time is between 20s and 40s.

[0128] This embodiment provides a reasonable range of values ​​for the first set time for the transfer vacuum threshold of 8E-6 Torr, which is typically set on the front-end inspection equipment of this invention. For example:

[0129] If the first set time is 20 seconds, after one vacuuming of the transfer chamber 20 for the first set time (assuming the second set time is 10 seconds), the first vacuum value usually cannot reach the wafer transfer vacuum threshold or the first vacuum threshold (e.g., 8E-5 Torr). Therefore, it is necessary to cycle at least once, that is, to perform another vacuuming for the first set time, before the corresponding wafer transfer to the main chamber 30 can be allowed.

[0130] If the first set time is 30 seconds, after the vacuuming of the transfer chamber 20 for the first set time (assuming the second set time is 10 seconds), the first vacuum value will reach the wafer transfer vacuum threshold or the first vacuum threshold (e.g., 8E-5 Torr). Therefore, after only one vacuuming, the wafer can be transferred to the main chamber 30.

[0131] If the first set time is 40 seconds, after the vacuuming of the transfer chamber 20 for the first set time (assuming the second set time is 10 seconds), the first vacuum value will have already reached the wafer transfer vacuum threshold. Therefore, performing vacuuming only once is a slight waste of vacuuming time, but the wafer can still be transferred to the main chamber 30.

[0132] In some preferred embodiments of the present invention, the control method of the present invention includes the following steps:

[0133] 1. After wafer 60 enters the transfer chamber, it is first evacuated normally. After the vacuum pump is turned on, the transfer chamber is evacuated for the first set time (e.g., 30s). Then, all gas valves 70 are closed (at this time, the vacuum pump also stops evacuating, the transfer chamber is in a closed state, and only wafer 60 releases gas in the transfer chamber). The second set time (e.g., 10s) is then measured by a measuring tool (gauge) to detect the second vacuum value in the loading lock cavity at this time (denoted as Cycle1-Vacuum).

[0134] 2. If the second vacuum value Cycle1-Vacuum in step 1 is less than the second vacuum threshold (e.g., 8E-5 Torr, which is a freely settable parameter (Spec)), then open gate valve 72 and continue to use the vacuum pump to evacuate the transfer chamber until the first vacuum value reaches the first vacuum threshold (i.e., the wafer transfer vacuum threshold, usually 8E-6 Torr); then transfer the wafer 60 to the main chamber 30.

[0135] 3. If the second vacuum value is greater than the second vacuum threshold, then reopen the gate valve 72; use the vacuum pump again to evacuate the transfer chamber for the first set time; then close the gate valve 72 for the second set time (e.g., 15s) and record the second vacuum value of the transfer chamber again (referred to as Cycle2-Vacuum).

[0136] 4. Determine whether the second vacuum value Cycle2-Vacuum in step 3 is less than the second vacuum threshold. If the second vacuum value Cycle2-Vacuum in step 3 still does not reach the second vacuum threshold, repeat this process until the vacuum value meets the requirements after closing the gate valve 72 for 10 seconds. Then, open the gate valve 72, evacuate the transfer chamber to the first vacuum threshold, and transfer the wafer 60 to the main chamber 30.

[0137] 5. If this process is repeated 10 times (Times, this value can be set freely) and the first vacuum threshold requirement is still not met, then the wafer 60 is returned to the wafer 60 box of the front-end module 10.

[0138] Steps 1-5 above combine to form a target operating mode that can be configured on the front-end inspection equipment. This target operating mode can be configured in two ways: tool configuration and parameter configuration. Tool configuration involves enabling and disabling the target operating mode during the initialization configuration phase of the front-end inspection equipment. The advantage of this method is its simplicity; however, its disadvantage is that for a normal wafer 60 without venting, at least one gate valve 72 closure vacuum check must be performed, affecting the inspection efficiency of wafer 60 and the yield of semiconductor chip manufacturing. Parameter configuration involves configuring tool-related and / or wafer 60-related parameters on the front-end inspection equipment. Once the target operating mode is imported into the front-end inspection equipment, it is automatically invoked using the configuration parameters (also known as the wafer 60 venting mode).

[0139] As an alternative to the step of measuring the second vacuum value after closing the gate valve 72 for a second set time in the above embodiments, in some other preferred embodiments of the present invention, after the vacuum pump is turned on for a first set time, the third vacuum value of the transfer chamber at this time (denoted as Cycle-Vacuum Gate on) can be recorded, then the gate valve 72 is closed for a second set time, and then the fourth vacuum value of the transfer chamber (denoted as Cycle-Vacuum Gate off) can be recorded. By comparing the difference between the third vacuum value and the fourth vacuum value, it is determined whether the wafer 60 is still venting in the transfer chamber.

[0140] The flowcharts provided in the embodiments of the present invention are not intended to indicate that the operations of the method will be performed in any particular order, or that all operations of the method are included in all every case. Furthermore, the method may include additional operations. Within the scope of the technical concept provided by the method of this embodiment, additional variations can be made to the above method.

[0141] It should be understood that in some embodiments, the components may be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods may be implemented using software or firmware stored in memory and executed by a suitable instruction execution system.

[0142] according to Figure 2 and Figure 3 As shown, in some other embodiments of the present invention, a front-end inspection device is also provided. This front-end inspection device may be an electron beam defect re-inspection device (DR-SEM) or a critical dimension measurement device (CD-SEM). The front-end inspection device includes a main body and a control device.

[0143] The main body of the equipment consists of a front-end module 10, a transfer chamber 20, and a main chamber 30. A door valve 40 is installed between the front-end module 10 and the transfer chamber 20, configured to control the connection and disconnection between the two. A vacuum transfer valve 50 is installed between the transfer chamber 20 and the main chamber 30, configured to control the connection and disconnection between the two. Furthermore, the transfer chamber 20 is connected to at least one vacuum pump via at least one air valve 70, and the at least one vacuum pump is configured to evacuate the transfer chamber 20.

[0144] The system includes three pumps: a main chamber molecular pump 81, a transfer chamber molecular pump 82, and a dry pump 83. The inlet of the main chamber molecular pump 81 is connected to the main chamber 30, and its outlet is connected to the dry pump 83 via a main chamber electronic valve 73. The inlet of the transfer chamber molecular pump 82 is connected to the transfer chamber 20 via a gate valve 72, and its outlet is connected to the dry pump 83 via a transfer chamber solenoid valve 74. The inlet of the dry pump 83 is connected to three parallel pumping branches: a main chamber pumping branch consisting of the main chamber electronic valve 73 and the main chamber molecular pump 81 connected in series; a first transfer chamber pumping branch consisting of a roughing valve 71; and a second transfer chamber pumping branch consisting of the gate valve 72, the transfer chamber molecular pump 82, and the transfer chamber. Furthermore, both the main chamber electronic valve 73 and the transfer chamber solenoid valve 74 use Turbo brand electromagnetic pulse valves, and both the main chamber electronic valve 73 and the transfer chamber solenoid valve 74 are normally open.

[0145] The control device is connected to the main body of the device and stores a computer program thereon. When executed by a processor, the computer program implements the steps of any of the control methods described above. The computer program used to perform the operations of this invention can be assembly instructions, Instruction Set Architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, integrated circuit configuration data, or source code or object code written in any combination of one or more programming languages ​​and procedural programming languages. The computer program can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer can connect to the user's computer via any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or it can connect to an external computer. In some embodiments, to perform aspects of the invention, electronic circuits, including, for example, programmable logic circuits, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), can execute computer-readable program instructions to personalize the electronic circuits by utilizing state information of computer-readable program instructions.

[0146] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A control method for a front-end inspection device, characterized in that, The front-end inspection equipment includes a main chamber for wafer inspection, the main chamber being connected to a transfer chamber via a vacuum transfer valve, the vacuum transfer valve being configured to connect or disconnect between the main chamber and the transfer chamber; the transfer chamber is connected to at least one vacuum pump via at least one air valve, the at least one vacuum pump being configured to evacuate the transfer chamber. as well as, The control method includes: S100, when the wafer is in the transfer chamber and the vacuum transfer valve is closed, open at least one of the gas valves and control at least one of the vacuum pumps to continuously evacuate the transfer chamber for a first set time. S200: After the vacuum chamber is evacuated for the first set time, all the gas valves are closed, and the vacuum state of the transfer chamber is obtained. S300, determine whether the vacuum state of the transfer chamber meets the preset conditions; S400, if satisfied, open at least one of the gas valves and continue to evacuate the transfer chamber until the vacuum value of the transfer chamber reaches the wafer transfer vacuum threshold. Then, allow the vacuum transfer valve to be opened and transfer the wafer from the transfer chamber to the main chamber; wherein the wafer transfer vacuum threshold is less than or equal to the set vacuum value of the main chamber.

2. The control method according to claim 1, characterized in that, In step S200, obtaining the vacuum state of the transfer chamber includes: The vacuum value of the transfer chamber is obtained after a second set time following the closure of all the aforementioned air valves, and is denoted as the first vacuum value; and, In S300, the preset conditions include the first vacuum value being less than or equal to the first vacuum threshold, and the first vacuum threshold being greater than or equal to the transfer vacuum threshold.

3. The control method according to claim 1, characterized in that, In step S200, obtaining the vacuum state of the transfer chamber includes: When the vacuum in the transfer chamber reaches the first set time, the vacuum value of the transfer chamber is obtained and recorded as the second vacuum value. The vacuum value of the transfer chamber is obtained after a third set time when all the gas valves are closed, and is recorded as the third vacuum value; Calculate the difference between the second vacuum value and the third vacuum value; and, In S300, the preset condition includes the difference being less than or equal to a difference threshold.

4. The control method according to claim 1, characterized in that, The front-end testing equipment also includes a front-end module connected to the transfer chamber via a gate valve, the gate valve being configured to connect or disconnect between the main chamber and the transfer chamber; as well as, Following S300, the following is also included: If the vacuum state of the transfer chamber does not meet the preset conditions, S100, S200 and S300 are repeated, and after the number of repetitions reaches the preset number, the gate valve is allowed to be opened, and the wafer is returned from the transfer chamber to the front-end module.

5. The control method according to claim 4, characterized in that, There are two air valves, one being a roughing valve and the other a gate valve. The roughing valve and the gate valve are connected in parallel between the air pump and the transfer chamber; and... In the first execution of S100, opening at least one of the air valves includes opening the coarse extraction valve and closing the gate valve; and / or, In the repeated execution of S100, opening at least one of the gas valves includes closing the coarse extraction valve and opening the gate valve.

6. The control method according to claim 5, characterized in that, In S400, opening at least one of the air valves includes closing the coarse extraction valve and opening the gate valve.

7. The control method according to claim 5, characterized in that, In the case of the first execution of S100, S100 further includes: The vacuum value of the transmission chamber within the first set time period is obtained and recorded as the fourth vacuum value; After the fourth vacuum value is less than or equal to the second vacuum threshold, the coarse pumping valve is closed and the gate valve is opened; wherein the second vacuum threshold is greater than or equal to the transfer vacuum threshold.

8. The control method according to claim 1, characterized in that, The following are included before S100: According to the preset initial configuration information and / or job configuration information, the target working mode of the front-end inspection equipment is activated; wherein, the initial configuration information describes the configuration information of the front-end inspection equipment in the initial state, the job configuration information describes the configuration information of the front-end inspection equipment in the job state, and the target working mode is used to enable the wafer to be transferred to the main chamber after the gas is released in the transfer chamber.

9. The control method according to claim 1, characterized in that, The transfer vacuum threshold is 8E-6 Torr, and the first set time is between 20 and 40 seconds.

10. A front-end inspection device, characterized in that, include: A main chamber for wafer inspection is connected to a transfer chamber via a vacuum transfer valve, the vacuum transfer valve being configured to connect or disconnect between the main chamber and the transfer chamber; the transfer chamber is connected to at least one vacuum pump via at least one air valve, the at least one vacuum pump being configured to evacuate the transfer chamber. A control device, wherein a computer program is stored on the control device, and the computer program, when executed by a processor, implements the steps of the control method according to any one of claims 1 to 9.

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