Front-end detection equipment and control method thereof

Abstract

The invention provides front-end detection equipment and a control method thereof. The control method comprises the following steps: after the transfer chamber is vacuumized for a first set time, closing all air valves, and obtaining a vacuum state of the transfer chamber; then, whether the vacuum state of the conveying chamber meets a preset condition or not is judged; if yes, opening at least one air valve, continuing to vacuumize the transfer chamber until the vacuum value of the transfer chamber reaches the wafer transfer vacuum threshold value, and allowing to open the vacuum transfer valve and transfer the wafer from the transfer chamber to the main chamber; wherein the wafer transfer vacuum threshold value is smaller than or equal to a set vacuum value of the main chamber. Compared with the prior art that threshold judgment and control are carried out after vacuumizing of the conveying chamber is completed, the control method achieves control over the vacuumizing process of the conveying chamber. Therefore, at least the waiting time in the existing vacuumizing time can be saved, and even the time length of the effective time in the existing vacuumizing time can be shortened, so that the effect of shortening the previous detection time of the wafer is realized.

Description

Technical Field

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

[0002] In some application scenarios of front-end inspection equipment for semiconductor manufacturing (such as electron beam defect review equipment (DR-SEM) and critical dimension measurement equipment (CD-SEM)), defect detection or critical dimension measurement is performed on wafers after photolithography in a high-vacuum main chamber. The vacuum degree of the main chamber is one of the important means to determine defect detection and critical dimension measurement. At present, some wafers processed by special photolithography processes are usually evacuated in the transfer chamber (Load Lock) according to the timed task execution mode (Fix Delay) before entering the main chamber, so as to release the gas in the photoresist on these wafers and prevent this part of the gas from destroying the high vacuum environment of the main chamber; among them, the evacuation scheme of the timed task execution mode is a scheme for evacuating the transfer chamber according to a fixed evacuation time. However, this vacuuming scheme has great limitations in front-end wafer inspection. For example, the fixed vacuuming time (for example, 10 minutes) is composed of an effective time for releasing the gas in the photoresist (i.e., the first 7 minutes of the 10 minutes) and another waiting time for redundant protection (i.e., the remaining 3 minutes of the 10 minutes). This waiting time is useless for front-end inspection of most wafers, resulting in a waste of time and reduced efficiency for front-end inspection of the wafer, which in turn leads to excessive restrictions on the throughput of the front-end inspection equipment. Summary of the invention

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

[0004] An object of the present invention is to solve the problem of wasted wafer front-end inspection time caused by the vacuum pumping scheme of the existing timed task execution mode, so as to achieve the purpose of shortening the wafer front-end inspection time.

[0005] Another object of the present invention is to improve the accuracy of detecting the vacuum value of the transfer chamber after evacuation, so as to achieve the purpose of improving the detection precision.

[0006] Specifically, in one aspect, the present invention provides a control method for a front-end inspection device, wherein the front-end inspection device comprises a main chamber for wafer inspection, wherein the main chamber is connected to a transfer chamber via a vacuum transfer valve, wherein the vacuum transfer valve is configured to connect or disconnect the main chamber and the transfer chamber; wherein the transfer chamber is connected to at least one vacuum pump via at least one gas valve, wherein at least one vacuum pump is configured to evacuate the transfer chamber; and

[0007] The control method comprises:

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

[0009] S200, after the transfer chamber is evacuated for the first set time, all the gas valves are closed to obtain a vacuum state of the transfer chamber;

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

[0011] S400, if satisfied, then 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 open 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.

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

[0013] Obtaining a vacuum value of the transfer chamber after closing all the gas valves for a second set time, recorded as a first vacuum value; and,

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

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

[0016] In response to the moment when the transfer chamber is evacuated to a vacuum state for the first set time, a vacuum value of the transfer chamber is obtained, which is recorded as a second vacuum value;

[0017] Obtaining a vacuum value of the transfer chamber after closing all the gas valves for a third set time, recorded as a third vacuum value;

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

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

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

[0021] After S300, the method further includes:

[0022] 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.

[0023] Preferably, there are two gas valves, which are a roughing valve and a gate valve, respectively. The roughing valve and the gate valve are arranged in parallel between the air pump and the transfer chamber; and,

[0024] When S100 is performed for the first time, the opening of at least one of the gas valves includes opening the roughing valve and closing the gate valve; and / or,

[0025] In the case of repeatedly executing S100, opening at least one of the gas valves includes closing the roughing valve and opening the gate valve.

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

[0027] Preferably, when S100 is performed for the first time, S100 further includes:

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

[0029] After the fourth vacuum value is less than or equal to the 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 the film transmission vacuum threshold.

[0030] Preferably, before S100, the method further includes:

[0031] According to preset initial configuration information and / or operating configuration information, the target operating mode of the front-end inspection equipment is turned on; wherein the initial configuration information describes the configuration information of the front-end inspection equipment in an initial state, the operating configuration information describes the configuration information of the front-end inspection equipment in an operating state, and the target operating mode is used to enable the wafer to be transferred to the main chamber after completing gas release in the transfer chamber.

[0032] Preferably, the sensor vacuum threshold is 8E-6 Torr, and the first setting time is between 20 seconds and 40 seconds.

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

[0034] A main chamber for wafer inspection, wherein the main chamber is connected to a transfer chamber via a vacuum transfer valve, and the vacuum transfer valve is configured to communicate or isolate between the main chamber and the transfer chamber; the transfer chamber is connected to at least one vacuum pump via at least one gas valve, and at least one vacuum pump is configured to evacuate the transfer chamber;

[0035] A control device is connected to the device body and stores a computer program thereon, and the steps of the above control method are implemented when the computer program is executed by a processor.

[0036] In the control method of the present invention, before the vacuum value of the transfer chamber reaches the vacuum threshold of the wafer transfer, it is judged whether the vacuum state of the transfer chamber meets the preset conditions, that is, before the vacuuming of the transfer chamber is completed, it is first judged whether the vacuuming process meets expectations, so as to control the vacuuming process according to the judgment result. Compared with the prior art that performs threshold judgment and control after the vacuuming of the transfer chamber is completed, the control method of the present invention realizes the control of the vacuuming process of the transfer chamber. According to the control of the vacuuming process of the transfer chamber, the control method of the present invention can detect the situation of the wafer releasing gas earlier, and can also make a decision on the vacuuming strategy adapted to the wafer earlier. For example, when the vacuum state of the transfer chamber meets the preset conditions, the control method of the present invention can judge that the time for the wafer to release gas is short, so there is no need to wait for the existing vacuuming time, and the wafer can complete the gas release, thereby at least saving the waiting time in the existing vacuuming time, and even shortening the effective time in the existing vacuuming time, thereby solving the problem of the wafer front-end detection time being wasted caused by the vacuuming scheme of the existing timed task execution mode, and achieving the effect of shortening the wafer front-end detection time.

[0037] Furthermore, in the control method of the present invention, by closing all gas valves and waiting for the second set time or the third set time, the wafer releases gas in a closed transfer chamber that has reached a vacuum state, so as to extend the time the wafer releases gas in a vacuum state, thereby increasing the effect of the wafer-released gas on the vacuum state in the transfer chamber, and making the vacuum value measurement result of the transfer chamber reflect the situation of the wafer-released gas more accurately, thereby improving the accuracy of the vacuum value detection of the transfer chamber after vacuuming, so as to achieve the purpose of improving the detection accuracy.

[0038] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

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

[0041] Figure 2 is a schematic diagram of the principle of a front-end inspection device according to an embodiment of the present invention;

[0042] Figure 3 is a flow chart of a control method according to an embodiment of the present invention when a vacuum state satisfies a preset condition;

[0043] Figure 4 is a flow chart of a control method according to an embodiment of the present invention;

[0044] Figure 5 is a schematic diagram of a flow chart of making a judgment according to a first vacuum value in a control method according to an embodiment of the present invention;

[0045] Figure 6 It is a schematic diagram of a flow chart of making judgments based on differences in a control method according to an embodiment of the present invention.

[0046] Among them: front-end module-10, transfer chamber-20, main chamber-30, gate valve-40, vacuum transfer valve-50, wafer-60, gas valve-70, rough pump 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, photolithography is the foundation and the most important link. The photoresist used in photolithography is a compound composed of soluble compounds and photosensitive materials. Not only does the photoresist undergo chemical reactions such as degradation and fusion in the solvent during photolithography, but it also releases gas under conditions such as heating, light, and atomic bombardment; and the wafer will continue to release gas for a certain period of time after photolithography. These wafers usually enter front-end inspection equipment such as electron beam defect review equipment (DR-SEM) and critical dimension measurement equipment (CD-SEM) to perform front-end inspection of the wafer in the high vacuum environment. However, the continuous release of gas from the wafer will destroy the high vacuum environment in the front-end inspection equipment, causing the front-end inspection equipment to shut down, shortening the normal working time (UP time) of the front-end inspection equipment, and even reducing the yield of semiconductor chips.

[0048] Figure 1 The main components of the existing front-end inspection equipment are shown in Figure 2. Figure 1 The existing front-end inspection equipment mainly consists of three parts: the front-end module 10 (EFEM), the transfer chamber 20 (Load Lock) and the main chamber 30 (Main Chamber). The wafer is transferred to the transfer chamber 20 through the external transfer mechanism in the front-end module 10; then, the transfer chamber 20 begins to be evacuated; then, after the vacuum value of the transfer chamber 20 reaches the set threshold (<5E-6Torr), the wafer is transferred to the main chamber 30 through the internal transfer structure; finally, in the main chamber 30, the wafer is subjected to defect re-inspection, key dimension measurement and other tasks. However, wafers that have undergone special photolithography processing will have a long-term continuous outgassing phenomenon (Outgassing Wafer). When such wafers are transferred to the transfer chamber through an external transfer structure, according to the normal wafer transfer process, the transfer chamber molecular pump 82 matched with the transfer chamber 20 will be turned on to evacuate the transfer chamber 20; then, the wafer is transferred to the main chamber 30, and such wafers are still continuously outgassing at this time. The gases released by these wafers will destroy the vacuum state of the main chamber 30, causing the front-end detection equipment to shut down.

[0049] In view of the above problems, the prior art proposes a vacuuming solution of a timed task execution mode (Fix Delay), which includes:

[0050] 1. After the wafer is transferred to the transfer chamber, the gate valve is closed, the rough pump 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-2Torr, close the roughing valve, open the gate valve, and use the transfer chamber molecular pump 82 type vacuum pump to evacuate the chamber;

[0052] 3. When the vacuum value in the transfer chamber reaches a first vacuum threshold (ie, the wafer transfer vacuum threshold, usually 8E-6 Torr), the wafer is transferred to the main chamber 30 via the internal transfer mechanism.

[0053] A fixed vacuuming time (e.g., 10 minutes) is set for the transfer chamber, and the vacuum value of the transfer chamber is detected when the vacuuming time is reached. If the vacuum value is less than or equal to the set threshold, the wafer is transferred to the main chamber 30 through the internal transfer structure. If the vacuum value is greater than the set threshold, the transfer chamber is inflated to the external atmospheric pressure (Vent LoadLock), and then the wafer is transferred to the wafer box (EFEM FOUP) in the front-end module 10 through the external transfer structure; or, if the vacuum value is greater than the set threshold, the transfer chamber is continuously vacuumed 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 front-end inspection equipment, in addition to wafer inspection accuracy, throughput is also a crucial indicator. Currently, based on manual experience, the vacuum pumping time set for the transfer chamber is usually longer than the continuous degassing time of the wafer (or there is still a small amount of degassing but it will not affect the inspection time in the main chamber 30). For example, the vacuum pumping time is usually set to 10 minutes, and the continuous degassing time of the wafer is 7 minutes. This will cause a waiting time of 3 minutes, resulting in too long preparation time before wafer inspection, reducing the number of wafers that have completed inspection on the front-end inspection equipment per unit time, that is, reducing the throughput of the front-end inspection equipment.

[0055] In some other prior arts, some special photolithography processes can cause severe long-term outgassing of the wafer. Usually, for this situation, the pumping speed of the vacuum pump should be greater than the outgassing rate of the wafer. Although the vacuum value inside the transfer chamber continues to decrease, the wafer is still continuously outgassed. If a vacuum pumping scheme with a timed task execution mode is adopted, after the vacuum pumping time is completed, although the vacuum value in the transfer chamber meets the wafer transfer vacuum threshold (that is, the vacuum value that can transfer the wafer from the transfer chamber to the main chamber 30) within a short period of time, the wafer is still in a state of continuous outgassing. Once the wafer enters the main chamber 30 through the internal transmission mechanism, the high vacuum environment of the main chamber 30 will be destroyed, and the front-end detection equipment will shut down.

[0056] In order to at least solve the problem of wasted wafer front-end inspection time caused by the vacuum pumping scheme of the timed task execution mode in the prior art, a control method for front-end inspection equipment is proposed in one embodiment of the present invention.

[0057] Figure 2 FIG. 2 shows a schematic diagram of the principle of a front-end detection device according to an embodiment of the present invention. Figure 2In one embodiment of the present invention, the front-end inspection equipment is also mainly composed of a front-end module 10, a transfer chamber 20 and a main chamber 30. A door valve 40 is provided between the front-end module 10 and the transfer chamber 20, and the door valve 40 is configured to control the connection and cutoff between the front-end module 10 and the transfer chamber 20. A vacuum transfer valve 50 is provided between the transfer chamber 20 and the main chamber 30, and the vacuum transfer valve 50 is configured to control the connection and cutoff between the transfer chamber 20 and the main chamber 30. In addition, the transfer chamber 20 is connected to at least one vacuum pump via at least one gas valve 70, and the vacuum pump is configured to vacuum the transfer chamber 20.

[0059] In some preferred embodiments of the present invention, Figure 2 As shown, there are multiple gas valves 70, one of which is a roughing valve 71 and the other 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 when either the roughing valve 71 or the gate valve 72 is opened, the air pump can communicate with the transfer chamber 20. The roughing valve 71 and the gate valve 72 are common valves in the vacuum system in the semiconductor manufacturing field. The main difference between the two is that the machining accuracy of the roughing valve 71 is relatively poor, so in the low-precision control stage, the roughing valve 71 is often used for flow and pressure control; while in the high-precision control stage, the gate valve 72 is often used for control.

[0060] In some preferred embodiments of the present invention, there are three air pumps, which are the main chamber molecular pump 81, the transfer chamber molecular pump 82 and the 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 via the main chamber electronic valve 73. The inlet of the transfer chamber molecular pump 82 is connected to the transfer chamber 20 via the gate valve 72, and the outlet of the transfer chamber molecular pump 82 is connected to the dry pump 83 via the transfer chamber electromagnetic valve 74. The inlet of the dry pump 83 is connected to three mutually parallel air pumping branches, which include the main chamber air pumping branch formed by the main chamber electronic valve 73 and the main chamber molecular pump 81 connected in series, the first transfer chamber air pumping branch composed of the rough pumping valve 71, and the second transfer chamber air pumping branch composed of the gate valve 72, the transfer chamber molecular pump 82 and the transfer chamber. The main chamber electronic valve 73 and the transfer chamber electromagnetic valve 74 both use Turbo brand electromagnetic pulse valves, and both the main chamber electronic valve 73 and the transfer chamber electromagnetic valve 74 are in a normally open state.

[0061] Figure 3 The present invention shows a schematic flow chart of a control method according to an embodiment of the present invention when the vacuum state meets the preset conditions. Figure 3 , and refer to Figure 2 and Figure 4It can be seen that, in one embodiment of the present invention, the control method for the front-end detection equipment of the present invention includes:

[0062] S100 , when the wafer 60 is in the transfer chamber 20 and the vacuum transfer valve 50 is closed, at least one gas valve 70 is opened, and the vacuum pump is controlled to continuously vacuum the transfer chamber 20 within a first set time.

[0063] Among them, the situation that the wafer 60 is in the transfer chamber 20 and the vacuum transfer valve 50 is closed usually refers to the situation that after the wafer 60 enters the transfer chamber 20 from the front-end module 10, the gate valve 40 and the vacuum transfer valve 50 are both in a closed state. At this time, the transfer chamber 20 is closed by the gate valve 40 and the vacuum transfer valve 50, and the gas released by the wafer 60 will all be located in the transfer chamber 20. Of course, in some prior arts, the purpose of evacuating the transfer chamber 20 is to make the vacuum value of the transfer chamber 20 consistent with the vacuum value of the main chamber 30, so that the transfer chamber 20 is used as an isolation buffer chamber to ensure that the vacuum value of the main chamber 30 is always at the set vacuum value. However, in the control method of the present invention, in addition to evacuating the transfer chamber for the above purpose, it will also be a very important purpose to ensure that all or most of the gas released by the wafer 60 is processed in the transfer chamber 20, otherwise the wafer 60 continues to release gas in the main chamber 30, which will have a relatively adverse effect on the detection of the wafer 60.

[0064] The vacuum transfer valve 50 is usually also disposed on the housing of the transfer chamber, and is configured to connect the transfer chamber and the main chamber 30 so that the transfer chamber and the main chamber 30 are under the same pressure condition, or to cut off the connection between the transfer chamber and the main chamber 30 so that the transfer chamber can maintain a vacuum state. The gate valve 40 is usually disposed on the housing of the transfer chamber, and is configured to connect the external atmospheric pressure environment and the transfer chamber so that the external atmospheric pressure environment and the transfer chamber are under the same pressure condition, or to cut off the connection between the external atmospheric pressure environment and the transfer chamber so that the transfer chamber can maintain a vacuum state.

[0065] Among them, the air valve in this embodiment specifically refers to a valve between the vacuum pump and the transfer chamber 20, which controls the on-off of the air path between the vacuum pump and the transfer chamber 20. When there is only one air valve 70, its own on-off can realize the on-off control between the vacuum pump and the transfer chamber 20. However, when the number of air valves 70 is more than two (for example, in some embodiments of the present invention, there are two air valves 70, and the two air valves 70 are respectively a rough pumping 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. In particular, when the combination of the two or more air valves 70 includes a parallel connection, the connection of the air valve 70 on any parallel branch can realize the connection between the vacuum pump and the transfer chamber; but only when at least one air valve 70 on all parallel branches is closed can the connection between the vacuum pump and the transfer chamber be cut off.

[0066] Among them, the first set time can be a preset fixed time value, such as 30s (i.e., 30 seconds); it can also be a time value calculated according to specific conditions, such as a variable time value set according to the photolithography processing of the wafer 60. Of course, no matter 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 the wafer needs 7min (i.e., 7 minutes) to release gas, then the first set time can be taken within the range of 7min. For example, the first set time is set to 30s. How to determine the time it takes for the wafer 60 to release gas after ordinary photolithography processing has nothing to do with the control method of the present invention, and it is also regarded as a prior art. For example, by sampling and analyzing the wafer after photolithography processing, the length of time the wafer releases gas is obtained; or, directly analyzing the time it takes for the wafer to release gas after photolithography processing based on the composition of the photoresist.

[0067] S200 , after the transfer chamber 20 is evacuated for a first set time, all the gas valves 70 are closed, and the transfer chamber 20 is in a vacuum state.

[0068] After the transfer chamber 20 is evacuated for the first set time, there are two possible states of the wafer 60 in the transfer chamber 20, one is that the gas has been completely or substantially released, and the other is that a large amount of gas is still being released. In order to facilitate the explanation and description of the control method of the present invention based on the wafer 60 in these two different states, we can define the former as a normal wafer and the latter as a long-term outgassing wafer.

[0069] As described in the previous paragraph, after the first set time of vacuuming, the common wafer has finished or substantially finished releasing gas in the transfer chamber 20, so after closing all the gas valves 70, the vacuum state of the transfer chamber 20 will be maintained or substantially maintained as the vacuum state before closing all the gas valves 70, which can also be said that the vacuum value of the transfer chamber 20 is consistent or substantially consistent before and after closing all the gas valves 70. Therefore, through step S200, the transfer chamber obtains a vacuum state that is close to or directly equal to the vacuum threshold of the wafer transfer.

[0070] In some cases, the length of the first set time can be appropriately shorter, so that although the ordinary wafer has not yet completed or substantially completed the release of gas, if it can be determined whether the wafer is an ordinary wafer or a long-term outgassing wafer after the wafer completes the release of gas for the first set time, the time length setting of the first set time will also be able to achieve an effect that is basically consistent with the above time length setting method. In some other cases, as long as the first set time is set short enough, although the ordinary wafer cannot complete or substantially complete the release of gas according to the first set time once; after multiple repetitions, the ordinary wafer can always complete or substantially complete the release of gas.

[0071] From the above, it can be seen that as long as the length of the first set time is less than the length of time that an ordinary wafer continuously releases gas, the wafer type can be determined before the transfer chamber 20 is evacuated to reach the wafer transfer vacuum threshold, thereby eliminating the waiting time in the existing vacuum pumping time.

[0072] The vacuum state reflects the effect of the gas released by the wafer 60 in the closed transfer chamber 20 on the vacuum value after the first set time. When the transfer chamber 20 is in a closed state, the gas released by the wafer 60 will be a determining factor affecting the vacuum value of the transfer chamber 20, and thus the vacuum state will be used as an important means to determine whether the wafer 60 is an ordinary wafer. If the wafer 60 is an ordinary wafer, then the gas released after the first set time will be less, and the effect on the vacuum value will not be obvious; otherwise, it is a long-term outgassing wafer, and the gas released will be more, and the effect on the vacuum value will be more obvious.

[0073] S300, determining whether the vacuum state of the transfer chamber 20 meets a preset condition.

[0074] In step S300, the determination of whether the vacuum state meets the preset conditions can indirectly determine which type of wafer 60 in the transfer chamber 20 belongs to (i.e., ordinary wafer or long-term outgassing wafer), so as to make more targeted decisions on the subsequent steps of the control method of the present invention. For example, when the vacuum state meets the preset conditions, we can determine that the wafer 60 in the transfer chamber 20 is an ordinary wafer, then in the subsequent steps, the vacuum will be pumped for a shorter period of time according to the gas release time of the ordinary wafer, and the wafer can be transferred to the main chamber 30; on the contrary, if it is determined that the wafer 60 in the transfer chamber 20 is a long-term outgassing wafer, it will be selectively continued to be pumped or directly returned to the front-end module 10 depending on the required gas release time.

[0075] Of course, the preset conditions are different according to the different states of the transfer chamber 20 reflected by the vacuum state. For example, if the vacuum state reflects the state that the ordinary wafers in the transfer chamber 20 can be completely or substantially completely released of gas, the preset conditions will be required according to the vacuum value of the transfer chamber 20 reaching or approaching the vacuum threshold of the transfer chamber; if the vacuum state reflects the state that the ordinary wafers in the transfer chamber 20 are still in the state of degassing, the preset conditions will be required according to the influence of the ordinary wafers on the vacuum state of the transfer chamber 20 under the corresponding conditions.

[0076] S400, when the vacuum state of the transfer chamber 20 meets the preset conditions, open at least one gas valve 70, and continue to evacuate the transfer chamber 20 until the vacuum value of the transfer chamber 20 reaches the wafer transfer vacuum threshold, allowing the vacuum transfer valve 50 to open and transfer the wafer 60 from the transfer chamber 20 to the main chamber 30; wherein the wafer transfer vacuum threshold is less than or equal to the set vacuum value of the main chamber 30.

[0077] In this embodiment, the fact that the vacuum state of the transfer chamber 20 meets the preset conditions reflects that the wafer 60 in the transfer chamber 20 is an ordinary wafer. Based on this, we can conclude that after the transfer chamber 20 is evacuated to the transfer vacuum threshold, the wafer 60 will end or substantially end releasing gas, and after the wafer 60 is transferred to the main chamber 30, the wafer 60 will not or substantially not affect the high vacuum condition of the main chamber 30, and the inspection operation of the wafer 60 can be completed normally.

[0078] Among them, the wafer transfer vacuum threshold is usually used as an important indicator to examine whether the vacuum value in the transfer chamber 20 is consistent with the vacuum value in the main chamber 30. That is, after the vacuum value in the transfer chamber 20 reaches the wafer transfer vacuum threshold, under normal circumstances (for example, for wafers 60 that do 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 usually maintains, and is also the vacuum value required to maintain high vacuum conditions when the main chamber 30 performs normal inspection operations.

[0079] In this embodiment, the control method of the present invention implements a strategy for process control of the vacuum pumping of the transfer chamber 20 according to the type of wafer 60 by evaluating the vacuum state in the transfer chamber 20 with preset conditions before the vacuum pumping of the transfer chamber 20 reaches the wafer vacuum threshold. Compared with the result control strategy of the existing vacuum pumping control, the control method of the present invention can flexibly adjust the time for vacuum pumping the transfer chamber 20 according to the type of wafer 60, especially when the wafer 60 is an ordinary wafer, at least the waiting time in the existing vacuum pumping time can be saved. At the same time, if the type of wafer can be determined earlier, sufficient time will be given to adjust the subsequent steps of processing the wafer. For example, if it is determined that the wafer is a long-term degassing type wafer, the time for processing such long-term degassing wafers can be further shortened by increasing the pumping speed of the vacuum pump, increasing the opening of the gas valve, and returning the front-end module 10.

[0080] Figure 4 FIG. 1 is a flow chart showing a control method according to an embodiment of the present invention. Figure 4 As shown, in some embodiments of the present invention, after S300, the following steps are further included:

[0081] S500, when 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 the wafer 60 to be retracted from the transfer chamber 20 to the front-end module 10.

[0082] First, to facilitate the subsequent explanation and description of the control method of the present invention, we can collectively refer to the processes of executing S100, S200 and S300 in this embodiment as executing the target step. In this embodiment, it is provided that in some cases, the processing of the wafer 60 can be completed by repeatedly executing the target step. For example, when the length of the first set time is set to be short, the first execution of the target step, or even the first few repeated executions of the target step, cannot make the vacuum state of the transfer chamber 20 meet the preset conditions, then continue to repeat the target step, thereby compensating for the improper value of the first set time; for another example, when the type of wafer 60 is between ordinary wafers and long-term degassing type wafers, the vacuum state of the transfer chamber 20 cannot reach the preset conditions by executing the target step once, or a small number of repeated executions of the target step, then the control method of the present invention can only be applied to this type of wafer 60 by increasing the number of repeated executions of the target.

[0083] However, the long-term outgassing type wafer takes a long time to release gas. If the control method of the present invention is also applied to the type of wafer 60 to which the control method of the present invention is applied, then a small number of long-term outgassing type wafers will occupy the transfer chamber 20 for a long time, while a large number of wafers 60 to be processed will be piled up in the front-end module 10, and the main chamber 30 will be idle for a long time. Therefore, in order to avoid the long-term occupation of the transfer chamber by these long-term outgassing type wafers, the present embodiment proposes a method of limiting the maximum number of repetitions of executing the target step, that is, a preset number of times, so that these long-term outgassing type wafers that still cannot be deflated after multiple repetitions are returned to the front-end module 10 to end their processing in the transfer chamber 20. In this way, it is possible to free up the processing space in the transfer chamber 20 and avoid the long-term outgassing type wafers entering the main chamber 30 to damage the high vacuum conditions.

[0084] For example, when the preset number of times is set to 10 times, if the vacuum state of the transfer chamber 20 still does not meet the preset conditions after the target step is executed for the first 9 times, the control method of the present invention will still loop to execute the target step; until the target step is executed for the 10th time and still cannot be met, 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).

[0085] Figure 5 FIG. 1 is a schematic diagram showing a flow chart of making a judgment based on a first vacuum value in an embodiment of the present invention. 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 closing all the gas valves 70 for a second set time, which is recorded as the first vacuum value.

[0086] Among them, the second set time can realize that the wafer 60 releases a detectable amount of gas under vacuum conditions. Specifically, in the first set time before the second set time, the vacuum pump evacuates the transfer chamber 20, especially when the wafer 60 in the transfer chamber 20 is an ordinary wafer, the vacuum value of the transfer chamber 20 may reach the transfer vacuum threshold after the first set time. In this way, when all the gas valves 70 are closed, the gas released by the wafer 60 will be the main factor affecting the vacuum value of the transfer chamber 20, so that the longer the second set time is, if the wafer 60 is still releasing gas, the greater the vacuum value of the transfer chamber 20 will be, thereby indirectly obtaining that the wafer 60 is a long-term degassing type wafer; on the contrary, if the wafer has finished or basically finished releasing gas, even if the second set time is very long, the vacuum value of the transfer chamber 20 will not change or will slightly increase. Therefore, through the change of the vacuum state in the second set time, the type of wafer can be conveniently and indirectly judged. At the same time, in order to reduce the influence 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, when the first set time is 30 seconds, the second set time may be 10 seconds or 15 seconds.

[0087] In S300, the preset conditions include that the first vacuum value is less than or equal to the first vacuum threshold, and the first vacuum threshold is greater than or equal to the film transmission vacuum threshold.

[0088] This embodiment provides a solution for using an absolute value to perform a judgment after a first set time. Specifically, based on the preferred embodiment provided in this embodiment, the control method of the present invention includes:

[0089] S100, when the wafer is in the transfer chamber and the vacuum transfer valve is closed, opening at least one of the gas valves, and controlling the vacuum pump to continuously evacuate the transfer chamber within a first set time;

[0090] S210, after the transfer chamber is evacuated for the first set time, all the gas valves are closed, and a vacuum value of the transfer chamber after all the gas valves are closed for a second set time is obtained, which is recorded as a first vacuum value;

[0091] S310, determining whether the first vacuum value is less than or equal to a first vacuum threshold;

[0092] S400, if satisfied (i.e. less than or equal to), then 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 open 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.

[0093] Therefore, this embodiment determines whether the vacuum state meets the preset condition by comparing the absolute values, specifically comparing 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 type of the wafer 60. On the other hand, when the value of the second vacuum threshold is greater than or equal to the wafer transfer vacuum threshold, there are two situations. First, when the second vacuum threshold is equal to the wafer transfer vacuum threshold, the gas released by 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 wafer 60, and the value of the second set time can be shortened accordingly; second, when the second vacuum threshold is greater than the wafer transfer vacuum threshold, more gas can be released from wafer 60 within the same second set time, that is, the requirements for wafer 60 can be relaxed, and it can be applicable to the pre-inspection preparation of wafer 60 that still has a small amount of outgassing in the main chamber 30; at the same time, the second can be applicable to the stage where wafer 60 is still in a large amount of outgassing, that is, the length of the first set time can be shortened (the shorter the first set time, the shorter the outgassing time of wafer 60), thereby further shortening the preparation time of wafer 60 before inspection.

[0094] Figure 6 FIG. 1 is a schematic diagram showing a flow chart of making a judgment based on a difference in a control method according to an embodiment of the present invention. 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:

[0095] In response to the moment when the vacuum of the transfer chamber reaches the first set time, a vacuum value of the transfer chamber is obtained, which is recorded as a second vacuum value;

[0096] Obtaining a vacuum value of the transfer chamber after closing all gas valves for a third set time, recorded as a third vacuum value;

[0097] The difference between the second vacuum value and the third vacuum value is calculated.

[0098] The moment of obtaining the second vacuum value may be before closing all the gas valves 70, after closing all the gas valves 70, or during the process of closing all the gas valves 70. Of course, it is preferably before closing all the gas valves 70, when the vacuum value of the transfer chamber 20 is the smallest among the above three, and the difference in this embodiment can be maximized to the greatest extent. The second vacuum value reflects the vacuum value in the transfer chamber at the end of the first set time. If the wafer 60 is an ordinary wafer, then within the third set time in the future, the effect of the gas released by the wafer 60 on the second vacuum value will be small or even have no effect, and the corresponding difference will also be the smallest; on the contrary, if the wafer 60 is a long-term degassing type wafer, the effect of the gas released by the wafer 60 on the second vacuum value will be large, and the corresponding difference will also be the largest.

[0099] Among them, the third setting time and the second setting time can be the same or different, but both are for achieving the release of the detected amount of gas from the wafer 60 under vacuum conditions. Compared with the vacuum value acquisition at the instant when the vacuum pumping time ends or during the vacuum pumping time in the prior art, this embodiment prolongs the static time of the transfer chamber in a closed state, so that the gas released by the wafer 60 has a more significant impact on the vacuum condition of the transfer chamber and is easier to measure. At the same time, in order to reduce the impact of the length of the third setting time on the preparation time before the front-end inspection of the wafer 60, the third setting time can also be as short as possible. For example, when the first setting time is 30s, the third setting time can be 10s or 15s.

[0100] Among them, when 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. The third vacuum value and the first vacuum value both reflect the vacuum value of the transfer chamber 20 under the influence of the wafer 60 after all the gas valves are closed for a period of time under vacuum conditions. Compared with the case where the first vacuum value is used for absolute value comparison in the above embodiment, the third vacuum value in this embodiment is calculated together with the second vacuum value for relative value comparison. Of course, in this embodiment, the difference = the second vacuum value - the third vacuum value, so under normal circumstances, the difference should be a negative value. For example, when the second vacuum value is 8E-6Torr, 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-5Torr, the difference will be -7.2E-5Torr.

[0101] In S300 , the preset condition includes that the difference is less than or equal to a difference threshold.

[0102] This embodiment provides a solution for using relative values ​​to perform a judgment after a first set time. Specifically, based on the preferred embodiment provided in this embodiment, the control method of the present invention includes:

[0103] S100, when the wafer is in the transfer chamber and the vacuum transfer valve is closed, opening at least one of the gas valves, and controlling the vacuum pump to continuously evacuate the transfer chamber within a first set time;

[0104] S220a, in response to the moment when the vacuum of the transfer chamber reaches the first set time, obtaining a vacuum value of the transfer chamber, recorded as a second vacuum value;

[0105] S220b, obtaining a vacuum value of the transfer chamber after all the gas valves are closed for a third set time, recorded as a third vacuum value;

[0106] S220c, calculating the difference between the second vacuum value and the third vacuum value;

[0107] S320, determining whether the difference is less than or equal to a difference threshold;

[0108] S400, if satisfied (i.e. less than or equal to), then 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 open 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.

[0109] Therefore, the embodiment is an alternative embodiment of the above-mentioned embodiment using the first vacuum value for absolute value judgment, and the main difference is that in this embodiment, a difference comparison is used to determine whether the vacuum state meets the preset condition. For example, when the second vacuum value is 8E-6Torr, 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-5Torr, the difference will be -7.2E-5Torr. Correspondingly, when the difference threshold is set to -7.2E-5Torr, we can find that the difference between the second vacuum value and the third vacuum value is exactly equal to the difference threshold, and it can be concluded that the vacuum state of the transfer chamber 20 meets the preset condition. Compared with the above-mentioned embodiment, which judges according to the first vacuum value after the second set time, this embodiment uses the difference of the vacuum values ​​corresponding to the start and end of the third set time (i.e., the second vacuum value and the third vacuum value) to make a judgment. The difference directly reflects the change amplitude of the vacuum state in the transfer chamber 20 within the third set time, especially when the second vacuum value is smaller, the difference will be more obvious. Therefore, relatively long-term outgassing type wafers are also easy to judge when using absolute value judgment. For ordinary wafers in which the gas released by wafer 60 within the third set time has little effect on the second vacuum value, the judgment method of this embodiment will be more applicable, and can further improve the accuracy of determining the type of wafer 60, thereby improving the accuracy of detecting the vacuum value of the transfer chamber after vacuuming, thereby more accurately performing the outgassing process before detecting wafer 60, saving the time for vacuuming the transfer chamber 20 to a certain extent, and improving the accuracy of wafer 60 detection.

[0110] like Figure 2 As shown, in some embodiments of the control method of the present invention, when S100 is executed for the first time, the opening of at least one gas valve includes opening a roughing valve and closing a gate valve; and / or,

[0111] In the case of repeatedly executing S100, the opening of at least one gas valve includes closing the roughing valve and opening the gate valve.

[0112] In this embodiment, at least three different combinations of two gas valves 70 are provided in the process of executing the target step, namely:

[0113] The first method is to use the roughing valve 71 when executing the target step for the first time, and then use the roughing valve 71 alone, the gate valve 72 alone, or a combination of the roughing valve 71 and the gate valve 72 when executing the target step thereafter;

[0114] The second method is to use the roughing valve 71 alone, the gate valve 72 alone, or a combination of the roughing valve 71 and the gate valve 72 when executing the department target step for the first time, and then use the gate valve 72 when executing the target step;

[0115] The third method is to use the roughing valve 71 when the target step is first executed, and use the gate valve 72 when the target step is executed thereafter.

[0116] Based on the different characteristics of the roughing valve 71 and the gate valve 72 in the vacuuming system, the first combination method is suitable for working scenarios where the valve precision is not high, the second combination method is suitable for working scenarios where the first rough / precise control and the subsequent precise control are performed, and the difference between the third combination method and the second combination method is that in the first execution process, the third combination method can only select rough control. These different combinations of the roughing valve 71 and the gate valve 72 also correspond to different wafers 60, that is, if the wafer 60 is not seriously deflated, rough control can be used, but if the wafer 60 is seriously deflated, the degree of precise control can be increased depending on the situation. Therefore, for ordinary wafers with less deflation, the frequency of use of the roughing valve 71 can be increased in this embodiment to achieve the purpose of low-cost control; and for long-term deflation type wafers with relatively more deflation, the frequency of use of the gate valve 72 can be increased in this embodiment, to improve the airtightness of the vacuuming pipeline to a certain extent, and to speed up the efficiency of vacuuming.

[0117] In some embodiments of the present invention, in S400, opening at least one of the gas valves includes closing a roughing valve and opening a gate valve.

[0118] In this embodiment, according to the characteristics of the roughing valve 71 and the gate valve 72, after determining the type of wafer 60, this embodiment uses the method of opening the gate valve 72 to perform vacuuming, which can achieve precise control in the final vacuuming stage and speed up the progress of vacuuming, thereby shortening the preparation time of the wafer 60 in the transfer chamber 20, and improving the yield of semiconductor chip manufacturing to a certain extent.

[0119] In some embodiments of the present invention, when S100 is performed for the first time, S100 further includes:

[0120] Obtaining a vacuum value of the transfer chamber within a first set time (i.e., when the transfer chamber is continuously evacuated), recorded as a fourth vacuum value;

[0121] After the fourth vacuum value is less than or equal to the 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 the film transmission vacuum threshold.

[0122] In this embodiment, when the target step is executed for the first time, the roughing valve 71 is opened and the gate valve 72 is closed, so that at the initial stage of vacuuming the transfer chamber 20, the control cost is small and the response speed is fast; and then, the roughing valve 71 is closed and the gate valve 72 is opened, that is, the switch from the roughing valve 71 to the gate valve 72 is performed, so that the roughing control in the first section of the first set time and the precise control in the latter section are combined. The switching basis for switching from the roughing control to the precise control is that the vacuum value (i.e., the fourth vacuum value) of the transfer chamber 20 reaches the second vacuum threshold (preferably, the second vacuum threshold is greater than the vacuum threshold of the film transfer, for example, when the vacuum threshold of the film transfer is 8E-6Torr, the second vacuum threshold is usually 5E-6Torr), so that the advantages of the economy of the roughing valve 71 and the precision of the gate valve 72 are taken into account, so that the process control of vacuuming the transfer chamber 20 is more reasonable and efficient.

[0123] In some embodiments of the present invention, before S100, the method further includes:

[0124] According to the preset initial configuration information and / or operation configuration information, the target operation mode of the front-end inspection equipment is turned on; wherein the initial configuration information describes the configuration information of the front-end inspection equipment in the initial state, the operation configuration information describes the configuration information of the front-end inspection equipment in the operation state, and the target operation mode is used to enable the wafer to be transferred to the main chamber after the gas release is completed in the transfer chamber.

[0125] Among them, the target working mode describes the control strategy used by the front-end detection equipment when processing the outgassing wafer 60. Compared with the front-end detection equipment without this target working mode or the target working mode is in the off state, for ordinary wafers, this target working mode will take into account the advantages of high efficiency and reliability in vacuum control. Of course, after the target working mode is turned off, the front-end detection equipment can also operate in other working modes. For example, run the vacuum scheme of the existing timed task execution mode, or run the vacuum scheme for wafers that do not outgas.

[0126] The initial configuration information describes the relevant configurations performed when the front-end inspection device of the present invention is initially set up (e.g., during factory settings, during debugging settings), such as when the target working mode is turned on or off according to user needs during factory settings. The operation configuration information can be for the conditions of the front-end inspection device itself, such as the operating parameters of the front-end inspection device, the position of the front-end inspection device in the semiconductor manufacturing front-end equipment; it can also be for the conditions of the wafer 60, such as the temperature of the wafer 60, the parameters of the photolithography, the type of photoresist, whether it is photolithographic or whether there is outgassing, etc.

[0127] This embodiment shows that in addition to the target working mode, the control method of the present invention may also include other working modes. In this way, when the target working mode is turned off in the initial state, or when the target working mode is turned off according to the job configuration information, it may also be necessary to evacuate the transfer chamber 20 according to other working modes. For example, in order to achieve wafer transfer when the pressure in the transfer chamber 20 and the main chamber 30 is consistent, the wafer 60 is directly sent to the main chamber 30 after the transfer chamber 20 is evacuated. This other working mode is more suitable for wafers 60 that have not been photolithographically processed or have not released gas after photolithography. In particular, when these other working modes are used, at least one step of determining the type of wafer 60 will be omitted, thereby further reducing the processing time of the wafer 60 in the transfer chamber before testing, and to a certain extent improving the yield of semiconductor chip manufacturing.

[0128] In some embodiments of the present invention, the sensor vacuum threshold is 8E-6 Torr, and the first setting time is between 20s and 40s.

[0129] This embodiment provides a reasonable range of values ​​for the first set time for the film transmission vacuum threshold value of 8E-6Torr, which is usually set on the front-end detection equipment of the present invention, for example:

[0130] When the first set time is 20s, after the transfer chamber 20 is vacuumed for the first set time (assuming the second set time is 10s), the first vacuum value usually cannot reach the wafer transfer vacuum threshold or the first vacuum threshold (for example, 8E-5Torr), so it is necessary to cycle at least once, that is, vacuumize for the first set time again, to allow the corresponding operation of transferring the wafer to the main chamber 30.

[0131] When the first set time is 30s, after the transfer chamber 20 is vacuumed for the first set time (assuming the second set time is 10s), the first vacuum value will be able to reach the wafer transfer vacuum threshold or the first vacuum threshold (for example, 8E-5Torr), so the wafer can be transferred to the main chamber 30 after only one vacuuming.

[0132] When the first set time is 40s, after the transfer chamber 20 is vacuumed for the first set time (assuming the second set time is 10s), the first vacuum value will have already reached the wafer transfer vacuum threshold, so only one vacuuming is performed, which slightly wastes the vacuuming time, but the wafer can also be transferred to the main chamber 30.

[0133] In some preferred embodiments of the present invention, the control method of the present invention comprises the following steps:

[0134] 1. After the wafer 60 enters the transfer chamber, it is first evacuated normally. After the vacuum pump is turned on, the transfer chamber is evacuated for a first set time (for example, 30 seconds), and 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 the wafer 60 releases gas in the transfer chamber) for a second set time (for example, 10 seconds), and the second vacuum value in the chamber of the loading lock at this time is detected by a measuring tool (Gauge) (recorded as Cycle1-Vacuum).

[0135] 2. If the second vacuum value Cycle1-Vacuum in step 1 is less than the second vacuum threshold (e.g., 8E-5Torr, which is a freely settable parameter (Spec)), open the gate valve 72 and continue to use the vacuum pump to evacuate the transfer chamber to the first vacuum value reaching the first vacuum threshold (i.e., the wafer transfer vacuum threshold, usually 8E-6Torr); then transfer the wafer 60 to the main chamber 30.

[0136] 3. If the second vacuum value is greater than the second vacuum threshold, 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 (for example, 15s), and record the second vacuum value of the transfer chamber again (recorded as Cycle2-Vacuum).

[0137] 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 requirement after closing the gate valve 72 for 10s; then, open the gate valve 72, evacuate the transfer chamber to the first vacuum threshold, and then transfer the wafer 60 to the main chamber 30.

[0138] 5. If the number of times this process is repeated reaches 10 times (Times, this value can be set freely) and the requirement of the first vacuum threshold is still not met, the wafer 60 is transferred back to the wafer 60 box of the front-end module 10.

[0139] The above steps 1-5 are combined into a target working mode that can be configured on the front-end inspection equipment. There are two ways to configure the target working mode, namely, machine configuration (By Tool) and parameter configuration (By Recipe). Among them, the machine configuration is to open and close the target working mode during the initialization configuration stage of the front-end inspection equipment. The advantage of this configuration method is that the configuration is simple; its disadvantage is that for a normal wafer 60 without outgassing, at least one vacuum judgment of the gate valve 72 closing must be completed, which affects the inspection efficiency of the wafer 60 and the yield of semiconductor chip manufacturing. Parameter configuration is to configure configuration parameters related to the machine and / or the wafer 60 to be tested on the front-end inspection equipment. Once the target working mode is imported on the front-end inspection equipment, the target working mode (also called the wafer 60 outgassing mode, Outgassing mode) is automatically called using the configuration parameters.

[0140] As an alternative to the step of measuring the second vacuum value after closing the gate valve 72 for the second set time in the above-mentioned embodiment, in other preferred embodiments of the present invention, after the vacuum pump is turned on for the first set time, the third vacuum value of the transfer chamber at this time (recorded as Cycle-Vacuum Gate on) is recorded, and then the gate valve 72 is closed for the second set time, and then the fourth vacuum value of the transfer chamber (recorded as Cycle-Vacuum Gate off) is recorded, and by comparing the difference between the third vacuum value and the fourth vacuum value, it is determined whether the wafer 60 is still being degassed in the transfer chamber.

[0141] The flow chart provided in the embodiments of the present invention is not intended to indicate that the operation of the method will be performed in any particular order, or that all operations of the method are included in all every case. In addition, the method may include additional operations. Within the scope of the technical ideas provided by the present embodiment method, additional changes may be made to the above method.

[0142] It should be understood that in some embodiments, each part can be implemented by hardware, software, firmware or a combination thereof. In the above embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system.

[0143] 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, which can be an electron beam defect review equipment (DR-SEM) or a critical dimension measurement equipment (CD-SEM). The front-end inspection device includes an equipment body and a control device.

[0144] The main body of the device is mainly composed of a front-end module 10, a transfer chamber 20 and a main chamber 30. A door valve 40 is provided between the front-end module 10 and the transfer chamber 20, and the door valve 40 is configured to control the connection and cutoff between the front-end module 10 and the transfer chamber 20. A vacuum transfer valve 50 is provided between the transfer chamber 20 and the main chamber 30, and the vacuum transfer valve 50 is configured to control the connection and cutoff between the transfer chamber 20 and the main chamber 30. In addition, the transfer chamber 20 is connected to at least one vacuum pump via at least one gas valve 70, and the at least one vacuum pump is configured to vacuum the transfer chamber 20.

[0145] There are three air pumps, which are the main chamber molecular pump 81, the transfer chamber molecular pump 82 and the 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 via the main chamber electronic valve 73. The inlet of the transfer chamber molecular pump 82 is connected to the transfer chamber 20 via the gate valve 72, and the outlet of the transfer chamber molecular pump 82 is connected to the dry pump 83 via the transfer chamber electromagnetic valve 74. The inlet of the dry pump 83 is connected to three mutually parallel air pumping branches, which include the main chamber air pumping branch formed by the main chamber electronic valve 73 and the main chamber molecular pump 81 connected in series, the first transfer chamber air pumping branch composed of the rough pumping valve 71, and the second transfer chamber air pumping branch composed of the gate valve 72, the transfer chamber molecular pump 82 and the transfer chamber. The main chamber electronic valve 73 and the transfer chamber electromagnetic valve 74 both use Turbo brand electromagnetic pulse valves, and both the main chamber electronic valve 73 and the transfer chamber electromagnetic valve 74 are in a normally open state.

[0146] The control device is connected to the device body and has a computer program stored thereon, and the computer program implements the steps of any of the above control methods when executed by the processor. The computer program used to perform the operation of the present invention can be an assembly instruction, an instruction set architecture (ISA) instruction, a machine instruction, a machine-related instruction, a microcode, a firmware instruction, a state setting data, a configuration data of an integrated circuit, or a source code or object code written in any combination of one or more programming languages ​​and process programming languages. The computer program can be executed entirely on the user's computer, partially on the user's computer, as an independent 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 may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer. In some embodiments, to perform various aspects of the present invention, electronic circuits including, for example, programmable logic circuits, field programmable gate arrays (FPGAs), or programmable logic arrays (PLAs) may execute computer-readable program instructions by utilizing state information of the computer-readable program instructions to personalize the electronic circuits.

[0147] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A control method for a front-end detection device, characterized in that: The front-end inspection equipment comprises a main chamber for wafer inspection, wherein the main chamber is connected to a transfer chamber via a vacuum transfer valve, wherein the vacuum transfer valve is configured to connect or isolate the main chamber and the transfer chamber; the transfer chamber is connected to at least one vacuum pump via at least one gas valve, wherein at least one vacuum pump is configured to vacuumize the transfer chamber; as well as, The control method comprises: S100, when the wafer is in the transfer chamber and the vacuum transfer valve is closed, opening at least one of the gas valves, and controlling at least one of the vacuum pumps to continuously vacuum the transfer chamber within a first set time; S200, after the transfer chamber is evacuated for the first set time, all the gas valves are closed to obtain a vacuum state of the transfer chamber; S300, determining whether the vacuum state of the transfer chamber meets a preset condition; S400, if satisfied, then 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 open 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 the step S200, obtaining the vacuum state of the transfer chamber includes: Obtaining a vacuum value of the transfer chamber after closing all the gas valves for a second set time, recorded as a first vacuum value; and, In S300, the preset condition includes that the first vacuum value is less than or equal to a first vacuum threshold, and the first vacuum threshold is greater than or equal to the film transmission vacuum threshold.

3. The control method according to claim 1, characterized in that: In the step S200, obtaining the vacuum state of the transfer chamber includes: In response to the moment when the transfer chamber is evacuated to a vacuum state for the first set time, a vacuum value of the transfer chamber is obtained, which is recorded as a second vacuum value; Obtaining a vacuum value of the transfer chamber after closing all the gas valves for a third set time, recorded as a third vacuum value; calculating a difference between the second vacuum value and the third vacuum value; and, In S300, the preset condition includes that the difference is less than or equal to a difference threshold.

4. The control method according to claim 1, characterized in that: The front-end inspection equipment further comprises a front-end module connected to the transfer chamber via a gate valve, wherein the gate valve is configured to connect or isolate between the main chamber and the transfer chamber; as well as, After S300, the method further includes: 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 gas valves, which are a rough pumping valve and a gate valve, respectively. The rough pumping valve and the gate valve are arranged in parallel between the air pump and the transfer chamber; and When S100 is performed for the first time, the opening of at least one of the gas valves includes opening the roughing valve and closing the gate valve; and / or, In the case of repeatedly executing S100, opening at least one of the gas valves includes closing the roughing 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 gas valves includes closing the roughing valve and opening the gate valve.

7. The control method according to claim 5, characterized in that: When the S100 is performed for the first time, the S100 further includes: obtaining a vacuum value of the transfer chamber within the first set time, recorded as a fourth vacuum value; After the fourth vacuum value is less than or equal to the 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 the film transmission vacuum threshold.

8. The control method according to claim 1, characterized in that: Before the S100, the method further includes: According to preset initial configuration information and / or operating configuration information, the target operating mode of the front-end inspection equipment is turned on; wherein the initial configuration information describes the configuration information of the front-end inspection equipment in an initial state, the operating configuration information describes the configuration information of the front-end inspection equipment in an operating state, and the target operating mode is used to enable the wafer to be transferred to the main chamber after completing gas release in the transfer chamber.

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

10. A front-end detection device, characterized in that: include: A main chamber for wafer inspection, wherein the main chamber is connected to a transfer chamber via a vacuum transfer valve, and the vacuum transfer valve is configured to communicate or isolate between the main chamber and the transfer chamber; the transfer chamber is connected to at least one vacuum pump via at least one gas valve, and at least one vacuum pump is configured to evacuate the transfer chamber; A control device having a computer program stored thereon, wherein 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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