Buffer device

Abstract

The utility model discloses a buffer device, which is arranged between a process cavity and a transmission cavity and comprises a buffer cavity, a wafer is transmitted between the process cavity and the transmission cavity through the buffer cavity, and the buffer device comprises a gas supply device used for providing purging gas for the buffer cavity; the air extracting device is used for extracting the purging gas in the buffer cavity; the controller is connected with the gas supply device and the gas extraction device and controls the gas supply device and the gas extraction device to alternately work, so that the gas pressure in the buffer cavity is increased to second gas pressure from first gas pressure within first preset time, and the gas pressure in the buffer cavity is increased to the second gas pressure within second preset time; the air pressure in the buffer cavity is reduced to the first air pressure from the second air pressure within second preset time; the buffer device can prevent the wafers conveyed out from the process cavity from carrying particulate matters to enter the transmission cavity, so that the processing yield of the wafers is improved, the cleaning frequency of the transmission cavity is reduced, and the stability of the process platform is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of semiconductor equipment, concretely relates to a buffer device. BACKGROUND

[0002] In the semiconductor processing technology, the wafer is processed in the process cavity, for example, in the CVD (chemical vapor deposition) cavity, the process gas is introduced to react on the wafer surface to generate a thin film, and various types of byproduct particles, such as organic matter, chloride, metal oxide, etc., are generated during the process. If these particles remain on the wafer, they will not only affect the purity of the thin film, but also affect the performance of the device made of the wafer.

[0003] At present, a vacuum pump is usually provided to pump the process cavity to remove the particle contaminants in the process cavity. However, this method is slow and inefficient, resulting in residual particle contaminants in the process cavity and on the wafer surface. Moreover, when the wafer is transferred from the process cavity to the low-pressure transfer cavity, the particle contaminants are easily introduced into the transfer cavity, thereby contaminating the transfer cavity. Furthermore, when the wafer is transferred to other process cavities in the transfer cavity for the next process, and when other wafers are transferred in the transfer cavity, other process cavities and wafers are also contaminated, resulting in a decrease in the yield of semiconductor processes. SUMMARY

[0004] The utility model aims at providing a buffer device arranged between the process cavity and the transfer cavity, which can remove the residual particles on the wafer, prevent the particle contaminants in the process cavity from entering the transfer cavity, and prevent the particles in the transfer cavity from entering the process cavity, thereby improving the yield of semiconductor processes.

[0005] To achieve the above-mentioned purpose, the utility model provides a buffer device arranged between the process cavity and the transfer cavity, which includes a buffer cavity for transferring the wafer between the process cavity and the transfer cavity. The buffer device comprises:

[0006] A gas supply device for providing purge gas into the buffer cavity;

[0007] A gas extraction device for extracting the purge gas in the buffer cavity;

[0008] A controller connected with the gas supply device and the gas extraction device, respectively, for controlling the gas supply device and the gas extraction device to work alternately, so as to raise the air pressure in the buffer cavity from a first air pressure to a second air pressure within a first preset time, and lower the air pressure in the buffer cavity from the second air pressure to the first air pressure within a second preset time.

[0009] Optionally, the controller controls the gas supply rate of the gas supply device and the gas extraction rate of the gas extraction device to increase the gas pressure in the buffer cavity from the first gas pressure to the second gas pressure within 10 seconds and to decrease the gas pressure in the buffer cavity from the second gas pressure to the first gas pressure within 120 seconds.

[0010] Optionally, the buffer cavity further comprises a support for placing the wafer, one end of the support being connected to the inner side of the sidewall of the buffer cavity and the other end extending to the interior of the buffer cavity.

[0011] Optionally, at least two layers of the supports are arranged in the vertical direction.

[0012] Optionally, the lowermost layer of the supports is used for placing the wafer transferred from the process cavity to the transfer cavity.

[0013] Optionally, the bottom of the buffer cavity is further provided with a cooling disc, and a cooling liquid flows through the cooling disc.

[0014] Optionally, the buffer cavity further comprises a driving device connected to the lowermost layer of the supports, for driving the lowermost layer of the supports to move downward or upward, so that the lowermost layer of the supports is close to the cooling disc or resets.

[0015] Optionally, the buffer device comprises two buffer cavities, the two buffer cavities are connected to the same transfer cavity, and the two buffer cavities are respectively connected to one process cavity.

[0016] Optionally, the first gas pressure is 0.01 Torr to 0.1 Torr, and the second gas pressure is 1 Torr to 700 Torr.

[0017] Optionally, the gas supply device comprises a mass flow controller, the mass flow controller is connected to the controller, and the controller controls the gas supply rate of the gas supply device by controlling the mass flow controller.

[0018] Optionally, the gas extraction device comprises a gas extraction pump.

[0019] Optionally, the gas extraction pump is connected to the controller, and the controller controls the gas extraction rate of the gas extraction device by controlling the rotating speed of the gas extraction pump.

[0020] Optionally, the gas extraction pump is provided with a throttle valve, the throttle valve is connected to the controller, and the controller controls the gas extraction rate of the gas extraction device by controlling the opening degree of the throttle valve.

[0021] Optionally, the buffer cavity has a first sidewall and a second sidewall, the first sidewall is provided with a first transfer door, and the second sidewall is provided with a second transfer door; the buffer cavity is communicated with the process cavity through the first transfer door, and the buffer cavity is communicated with the transfer cavity through the second transfer door.

[0022] Compared with the prior art, the buffer device has at least the following advantages and beneficial effects:

[0023] In the buffer device, the gas supply device for providing purge gas into the buffer cavity and the air extraction device for extracting the purge gas in the buffer cavity are arranged, and the controller is arranged to control the gas supply device and the air extraction device to work alternately, so that the air pressure in the buffer cavity is increased from low pressure to high pressure and then rapidly decreased from high pressure to low pressure, a high-speed airflow is formed to purge the wafer in the buffer cavity, and the wafer carrying particles transmitted from the process cavity into the transfer cavity and causing pollution are prevented, and then the wafer carrying particles pollute other process cavities, and the wafer carrying particles pollute other wafers passing through the transfer cavity, the processing yield of the wafer is improved, the cleaning frequency of the transfer cavity is reduced, and the stability of the process platform is improved.

[0024] In the buffer cavity, at least two layers of supports are arranged to place the wafers, the processed wafers are placed on the lowermost layer, and the wafers to be processed are placed on the supports other than the lowermost layer, so that the particles on the surface of the processed wafers pollute the wafers to be processed; by arranging the multiple layers of supports, the time for the process cavity to wait for the wafer to be processed is saved, the processing times of the process cavity are increased, and the wafer processing efficiency is improved.

[0025] The cooling disc is arranged in the buffer cavity to cool the processed wafers, the processed wafers do not need to be transmitted to other modules for cooling, the overall wafer processing efficiency is improved, and the oxidation of the film layer of the processed wafers in the transmission process is prevented to affect the electrical properties. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A schematic view of the existing wafer entering the transfer cavity from the process cavity;

[0027] Figure 2 A top view of the buffer device of the utility model;

[0028] Figure 3 A side view of the buffer device of the utility model;

[0029] Figure 4 A top view of another buffer device of the utility model;

[0030] Figure 5Another side view of the buffer device of the utility model

[0031] Figure 6 Another plan view of the buffer device of the utility model

[0032] Figure 7 Another front view of the buffer device of the utility model. DETAILED DESCRIPTION

[0033] The technical solutions, structural features, purposes achieved and effects of the embodiments of the utility model will be described in detail below. Figures 1-7

[0034] It should be noted that the drawings are very simplified and all use non-precise proportions, only to facilitate and clarify the purpose of assisting the description of the embodiments of the utility model, and are not intended to limit the conditions of the embodiments of the utility model, so they do not have substantial technical significance, any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the utility model, should still fall within the scope of the technical content disclosed by the utility model.

[0035] It should be noted that in the utility model, the term "includes", "contains" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes the explicitly listed elements, but also includes other elements not explicitly listed, or includes elements inherent to such process, method, article or device.

[0036] At present, in the semiconductor process platform, as shown in Figure 1 Because there are particle pollutants formed by process by-products in the process cavity 10, in the process of transmitting the processed wafer W' from the process cavity 10 to the transmission cavity 20, the particle pollutants will enter the transmission cavity 20, and then when other wafers pass through the transmission cavity 20 to enter the process cavity 10, they will also be contaminated by the particle pollutants in the transmission cavity 20. In addition, because there are particle pollutants in the transmission cavity 20, when the processed wafer W' or other wafers are transmitted from the transmission cavity 20 to other process cavities, the particle pollutants will also contaminate other wafers and enter other process cavities to form contamination, ultimately leading to a decrease in the overall yield of semiconductor processes.

[0037] ​In order to solve the above problems, the utility model provides a buffer device which is arranged between a process cavity and a transmission cavity, comprising a buffer cavity, a gas supply device, a gas extraction device and a controller, the gas supply device and the gas extraction device are controlled to work alternately by the controller, the air pressure in the buffer cavity changes from low pressure to high pressure and then from high pressure to low pressure, so that the air pressure in the buffer cavity changes rapidly, a high-speed airflow is generated, and the particle pollutants in the buffer cavity and on the surface of a wafer in the buffer cavity are swept and removed, so that the particle pollutants are prevented from entering the transmission cavity or the process cavity subsequently to cause pollution, other wafers passing through the transmission cavity are also prevented from being polluted, and the process yield is improved.

[0038] The technical scheme of the utility model will be described in detail below with reference to the drawings and embodiments.

[0039] As shown in the drawings, Figure 2 The buffer device of the embodiment is arranged between a process cavity 30 and a transmission cavity 50, the process cavity 30 is any one of process cavities in a semiconductor process platform, the semiconductor process platform usually has a plurality of process cavities to perform different process treatments, and the transmission cavity 50 connects the plurality of process cavities and sequentially transports wafers into the process cavities for treatment. The buffer device comprises a buffer cavity 40 which is used to transport wafers between the process cavity 30 and the transmission cavity 50. A wafer W to be treated is transported into the buffer cavity 40 from the transmission cavity 50 for temporary storage, is subjected to a sweeping treatment in the buffer cavity 40, and is then transported into the process cavity 30 from the buffer cavity 40 for process treatment; a wafer W' which has been treated is transported into the buffer cavity 40 from the process cavity 30 for temporary storage, is subjected to a sweeping treatment in the buffer cavity 40, and is then transported into the transmission cavity 50 from the buffer cavity 40, and the transmission cavity 50 then transports the wafer W' which has been treated into other process cavities for other process steps.

[0040] As shown in the drawings, Figure 3 The buffer device further comprises a gas supply device 41 and a gas extraction device 42. The gas supply device 41 comprises a sweeping gas source 411 and a gas supply pipeline 412, the gas supply pipeline 412 has two ports, one of which is connected with the sweeping gas source 411, and the other of which is arranged in the buffer cavity 40, so that the sweeping gas source 411 is connected with the buffer cavity 40 through the gas supply pipeline 412, and the gas supply device 41 can supply sweeping gas into the buffer cavity 40. The gas extraction device 42 comprises a gas extraction pump 421 and a gas extraction pipeline 422, the gas extraction pipeline 422 has two ports, one of which is connected with the gas extraction pump 421, and the other of which is arranged in the buffer cavity 40, so that the gas extraction pump 421 is connected with the buffer cavity 40 through the gas extraction pipeline 422, and the gas extraction device 42 can extract the sweeping gas in the buffer cavity 40.

[0041] The port of the gas supply pipeline 412 in the buffer cavity 40 is located at the top center or top periphery of the buffer cavity 40, and the port of the gas extraction pipeline 422 in the buffer cavity 40 is located at the bottom center or bottom periphery of the buffer cavity 40, so that the flow of the purge gas has an upward direction. In this embodiment, the port of the gas supply pipeline 412 is located at the top center of the buffer cavity 40, and the port of the gas extraction pipeline 422 is located at the bottom center of the buffer cavity 40.

[0042] The purge gas is an inert gas, such as a mixture of one or more of N2 (nitrogen), He (helium), Ar (argon), etc. The gas extraction pump 421 can be a dry pump or a molecular pump, etc.

[0043] The buffer device further comprises a controller 43 connected with the gas supply device 41 and the gas extraction device 42 respectively to control the working states of the gas supply device 41 and the gas extraction device 42. When the processed wafer W' is transferred from the process cavity 30 into the buffer cavity 40, or when the to-be-processed wafer W is transferred from the transfer cavity 50 into the buffer cavity 40, the controller 43 controls the gas supply device 41 to work to fill the purge gas into the buffer cavity 40, so that the air pressure in the buffer cavity 40 is increased from low pressure to high pressure within a first preset time; and then controls the gas extraction device 42 to work to extract the purge gas in the buffer cavity 40, so that the air pressure in the buffer cavity 40 is decreased from high pressure to low pressure within a second preset time. The controller 43 controls the gas supply device 41 and the gas extraction device 42 to work alternately, so that the air pressure in the buffer cavity 40 is rapidly increased and then decreased, thereby generating a high-speed airflow in the buffer cavity 40, which carries the particulate contaminants on the processed wafer W' or the to-be-processed wafer W and the particulate contaminants in the buffer cavity 40 to be discharged, thereby playing a role of removing the particulate contaminants. Further, the controller 43 controls the gas supply device 41 and the gas extraction device 42 to repeat the above-mentioned alternating work several times, so that the particulate contaminants in the buffer cavity 40 are removed to the greatest extent.

[0044] The low pressure refers to an air pressure of 0.01 Torr to 0.1 Torr, and the high pressure refers to an air pressure of 1 Torr to 700 Torr. The first preset time is 10 seconds, and the second preset time is 120 seconds.

[0045] By using the above buffer device, when the wafer (the wafer to be processed W or the wafer processed W') enters the buffer cavity 40, the controller 43 controls the air pressure in the buffer cavity 40 to be rapidly increased from low and then rapidly decreased from high, so as to generate a high-speed airflow, which blows away the particle contaminants carried by the wafer, and then when the wafer is transferred from the buffer cavity 40 to the process cavity 30 or the transfer cavity 50, since there are almost no particle contaminants on the wafer surface and in the buffer cavity 40, the particle contaminants will not contaminate the process cavity 30 or the transfer cavity 50 along with the wafer transfer. Moreover, since the transfer cavity 50 needs to frequently transfer different wafers into different process cavities for different process treatments, ensuring the cleanliness of the transfer cavity 50 can prevent other wafers entering the transfer cavity 50 and other process cavities from being contaminated, finally achieving the effect of improving the yield of semiconductor processes, and also reducing the cleaning frequency of the transfer cavity 50, prolonging the service life of the transfer cavity 50, and improving the stability of the process platform.

[0046] Compared with the airflow generated by continuously operating the gas supply device 41 and the air exhaust device 42, the airflow generated by alternately operating the gas supply device 41 and the air exhaust device 42 in the embodiment is faster, and the blowing force and efficiency for the particle contaminants in the buffer cavity 40 are greater, so that a better effect of removing the particle contaminants can be achieved.

[0047] The controller 43 controls the gas supply rate of the gas supply device 41 and the air exhaust rate of the air exhaust device 42 to change the air pressure in the buffer cavity 40 within a set time. Specifically, the gas supply device 41 further includes a mass flow controller 413 arranged on the gas supply pipeline 412, and the controller 43 controls the mass flow controller 413 to control the flow of the blowing gas entering the buffer cavity 40, thereby controlling the gas supply rate of the gas supply device 41. In addition, the controller 43 is connected with the air exhaust pump 421 to control the rotating speed of the air exhaust pump 421, thereby controlling the air exhaust rate of the air exhaust device 42.

[0048] In other embodiments, a throttle valve is arranged on the air exhaust device 42, and the controller 43 is connected with the throttle valve to control the opening degree of the throttle valve, thereby controlling the air exhaust rate of the air exhaust device 43.

[0049] As Figure 2As shown, the buffer cavity 40 is rectangular, and a first sidewall 401 and a second sidewall 402 of the buffer cavity 40 are oppositely arranged. A first transfer door is formed on the first sidewall 401, and the buffer cavity 40 is communicated with the process cavity 30 through the first transfer door. A second transfer door is formed on the second sidewall 402, and the buffer cavity 40 is communicated with the transfer cavity 50 through the second transfer door. The first transfer door and the second transfer door are interlocked and cannot be opened at the same time, so as to avoid that when one of the transfer doors is opened to transfer the wafer W, the other transfer door is opened due to misoperation, and the particle contaminants in the process cavity 30 or the transfer cavity 50 directly enter the transfer cavity 50 or the process cavity 30 through the buffer cavity 40.

[0050] As shown in Figure 2 and Figure 3 The buffer cavity 40 is provided with a support 44 to place the wafer. When the wafer is transferred from the process cavity 30 or the transfer cavity 50 to the buffer cavity 40 for purging treatment, the wafer is placed on the support 44. One end of the support 44 is connected to the inner side of the sidewall of the buffer cavity 40, and the other end extends to the inside of the buffer cavity 40, so as to protrude from the inner side of the sidewall of the buffer cavity 40 to support the wafer.

[0051] In this embodiment, the support 44 includes four separate sub-supports, and the four sub-supports are symmetrically arranged on the third sidewall 403 and the fourth sidewall 404 of the buffer cavity 40, so as to stably support the wafer, and since the arrangement position of the support does not coincide with the transfer door, the wafer transfer is not hindered. In other embodiments, the sub-supports can also be other numbers, for example, six, eight, etc.

[0052] In this embodiment, two of the supports 44 are arranged in the vertical direction to form two layers, i.e., an upper layer and a lower layer, in the buffer cavity 40, so that two wafers can be stored in the buffer cavity 40 and subjected to the purge process. The upper layer is used to store the wafer W to be processed, which is subsequently transferred into the process cavity 30 for processing. The lower layer is used to store the processed wafer W', which is subsequently transferred into the transfer cavity 50 and then into another process cavity. Since the processed wafer W' has been subjected to the processing in the process cavity 30, it carries new particle contaminants generated in the process cavity 30. Compared with the wafer W to be processed, which has not been subjected to the processing in the process cavity 30, the number and types of the particle contaminants on the processed wafer W' are more than those on the wafer W to be processed, even if the wafer W to be processed has been subjected to the processing in another process cavity. Therefore, the processed wafer W' transferred from the process cavity 30 into the transfer cavity 50 is stored in the lower layer, so that when the purge gas is used to purge the processed wafer W' and the wafer W to be processed in the buffer cavity 40, the particle contaminants on the processed wafer W' will not contaminate the wafer W to be processed in the upper layer, since the processed wafer W' is located in the lower layer and the purge gas flows from top to bottom. Even if the particle contaminants on the processed wafer W' are blown away and adhere to the sidewall of the buffer cavity 40, since the processed wafer W' is located in the lower layer and the purge gas flows from top to bottom, the particle contaminants carried by the purge gas can only adhere to the lower part of the sidewall of the buffer cavity 40 during the purge process, so that the particle contaminants on the sidewall of the buffer cavity 40 will not easily contaminate and adhere to the surface of the wafer W to be processed in the upper layer when the wafer W to be processed is subsequently transferred into the buffer cavity 40.

[0053] When one wafer W to be processed is transferred into the buffer cavity 40 and subjected to the purge process, and then is transferred into the process cavity 30 for processing, since the processing time is long, if another wafer W to be processed is transferred into the process cavity 30 for processing, the wafer W to be processed can be temporarily stored in the buffer cavity 40 and placed in the upper layer, so as to wait for the process cavity 30 to complete the processing of the wafer W' to be processed, and then the wafer W' to be processed is transferred from the process cavity 30 into the buffer cavity 40 and placed in the lower layer for the purge process. After that, the wafer W to be processed temporarily stored in the buffer cavity 40 is transferred into the process cavity 30, so that the time for waiting for the transfer cavity 50 to transfer the wafer W to be processed from another cavity is saved, the number of times for the process cavity 30 to perform the processing is increased, and the wafer processing efficiency is improved.

[0054] The support 44 is made of ceramic material. Since the process temperature in the process chamber 30 is high, the processed wafer W' has a high temperature. In order to avoid the influence of the high temperature wafer on the service life of the support 44, the support 44 is made of high temperature resistant material. In other embodiments, the support 44 can also be made of other high temperature resistant materials.

[0055] In more embodiments, the number of layers of the support 44 can also be arranged in the vertical direction. When the number of layers of the support 44 is three, the three layers of the support 44 are arranged in the vertical direction to form an upper layer support, a middle layer support and a lower layer support. The lower layer support is used to place the processed wafer W' to be sent to the transfer chamber 50, and the upper layer support and the middle layer support are used to place the wafer W to be processed to be sent to the process chamber 30. By placing the processed wafer W' in the lowermost layer, the particle contaminants on the surface of the processed wafer W' can be prevented from contaminating the wafers W to be processed in the upper layer and the middle layer. Furthermore, placing two layers of supports to place the wafers to be processed can further increase the number of wafer temporary storage in the buffer chamber 40, so that the buffer chamber 40 can temporarily store at most two wafers W to be processed, which helps to increase the working time of the process chamber 30, thereby improving the efficiency of semiconductor processing. When the number of layers of the support 44 is more, such as four layers, five layers, etc., they are arranged in the vertical direction, and the lowermost layer of the support is used to place the processed wafer W', and the other layers of the support are used to place the wafer W to be processed, so as to ensure that the wafer W to be processed is not contaminated by the particle contaminants carried by the processed wafer W'.

[0056] When the above-mentioned buffer device is used to transfer the wafer between the process chamber 30 and the transfer chamber 50, the controller 43 controls the gas supply rate of the gas supply device 41 and the gas extraction rate of the gas extraction device 42, so that there is a negative pressure difference between the adjacent two chambers during the transfer process, that is, the gas pressure of the chamber where the wafer is transferred out is lower than the chamber where the wafer is transferred in, so as to prevent the particle contaminants from entering the chamber where the wafer is transferred in to a certain extent.

[0057] Specifically, when the processed wafer W' is transferred from the process chamber 30 to the transfer chamber 50, the wafer transfer method comprises the following steps:

[0058] S11, the controller 43 controls the gas supply rate of the gas supply device 41 and the gas extraction rate of the gas extraction device 42, so that the gas pressure in the buffer chamber 40 is higher than that in the process chamber 30, and the pressure difference between them is less than 0.5 Torr; at this time, the first transfer door and the second transfer door of the buffer chamber 40 are closed;

[0059] S12, open the first transfer door, transfer the processed wafer W' in the process chamber 30 to the buffer chamber 40 and place it on the lowermost layer of the support 44, and then close the first transfer door;

[0060] Since the air pressure in the buffer chamber 40 is higher than that in the process chamber 30, the gas and the particle contaminants in the gas in the process chamber 30 are prevented from entering the buffer chamber 40 and contaminating the buffer chamber 40 and the wafer W' to be treated in the buffer chamber 40 when the first transfer door is opened;

[0061] S13, the controller 43 controls the gas supply rate of the gas supply device 41 and the air exhaust rate of the air exhaust device 42, so that the air pressure in the buffer chamber 40 is increased to 1 Torr-700 Torr within 10 seconds and then decreased to 0.01 Torr-0.1 Torr within 120 seconds, so that a high-speed air flow from top to bottom is generated in the buffer chamber 40 to blow away the particle contaminants on the surface of the wafer W'; the step is repeated several times to remove the particle contaminants on the surface of the wafer W' to the greatest extent;

[0062] S14, the controller 43 controls the gas supply rate of the gas supply device 41 and the air exhaust rate of the air exhaust device 42, so that the air pressure in the buffer chamber 40 is lower than that in the transfer chamber 50 and the pressure difference between them is less than 0.5 Torr;

[0063] S15, the second transfer door is opened to transfer the wafer W' in the buffer chamber 40 to the transfer chamber 50, and then the second transfer door is closed; the transfer chamber 50 can transfer the wafer W' to other process chambers at this time.

[0064] Correspondingly, when the wafer W to be treated is transferred from the transfer chamber 50 to the process chamber 30, the wafer transfer method comprises the following steps:

[0065] S21, the controller 43 controls the gas supply rate of the gas supply device 41 and the air exhaust rate of the air exhaust device 42, so that the air pressure in the buffer chamber 40 is lower than that in the transfer chamber 50 and the pressure difference between them is less than 0.5 Torr; at this time, the first transfer door and the second transfer door of the buffer chamber 40 are closed;

[0066] S22, the second transfer door is opened to transfer the wafer W to be treated in the transfer chamber 50 to the buffer chamber 40 and place it on the other supports except the lowermost support, and then the second transfer door is closed;

[0067] At this time, since the air pressure in the buffer chamber 40 is lower than that in the transfer chamber 50, the gas and the particle contaminants in the gas in the buffer chamber 40 are prevented from entering the transfer chamber 50 and contaminating the transfer chamber 50, and further contaminating other wafers passing through the transfer chamber 50 when the second transfer door is opened;

[0068] S23, the controller 43 controls the gas supply rate of the gas supply device 41 and the pumping rate of the pumping device 42 to increase the pressure in the buffer chamber 40 to 1 Torr-700 Torr within 10 seconds and then decrease the pressure to 0.01 Torr-0.1 Torr within 120 seconds, so that a high-speed airflow from top to bottom is generated in the buffer chamber 40 to blow off the particle contaminants on the surface of the wafer W to be processed; the step is repeated several times to remove the particle contaminants on the surface of the wafer W to be processed to the greatest extent.

[0069] Since the wafer to be processed may have been processed in other process chambers and thus carries particle contaminants, or may have been contaminated with particle contaminants in the transfer chamber 50, the surface of the wafer W to be processed is blown off before it enters the process chamber 30 for processing, which helps to improve the process effect and yield;

[0070] S24, the controller 43 controls the gas supply rate of the gas supply device 41 and the pumping rate of the pumping device 42 to make the pressure in the buffer chamber 40 higher than that in the process chamber 30 and the pressure difference between them less than 0.5 Torr, so as to prevent the particle contaminants in the buffer chamber 40 from entering the process chamber 30 when the first transfer door is opened;

[0071] S25, the first transfer door is opened to transfer the wafer W to be processed in the buffer chamber 40 to the process chamber 30, and then the first transfer door is closed; the process chamber 30 can now process the wafer W to be processed.

[0072] By using the above buffer device and wafer transfer method, the wafer W to be processed or the wafer W' processed is blown off by high-speed airflow after entering the buffer chamber 40 to remove the particle contaminants on the surface of the wafer, so as to prevent subsequent contamination of the process chamber 30 or the transfer chamber 50, thereby improving the process yield of the wafer, reducing the cleaning frequency of the transfer chamber 50, and improving the stability of the semiconductor process platform.

[0073] In another embodiment, as shown in Figure 4 and Figure 5 based on the above embodiment, the bottom central region of the buffer chamber 40 is further provided with a cooling disc 45 for cooling the wafer W' processed above, and the cooling disc 45 is opposite to the position of the wafer W' processed above. In this embodiment, the port of the pumping pipeline 422 in the buffer chamber 40 is located at the bottom edge region of the buffer chamber 40.

[0074] When the processed wafer W' is transferred out of the process cavity 30, the processed wafer W' has a high temperature due to the high-temperature process in the process cavity 30, for example, the processing temperature of the chemical vapor deposition process can reach several hundred degrees Celsius. In order to cool the processed wafer W', the processed wafer W' is usually transferred to a load lock module or a front-end module for cooling, but during the transfer process and the cooling process, the film layer of the processed wafer W' can be oxidized by reacting with oxygen in the air, thereby affecting its electrical properties, and since each processed wafer W' needs to be cooled, the processing efficiency of the load lock module or the front-end module is also low, thereby reducing the production capacity of the semiconductor process platform. Therefore, the embodiment adopts the cooling disc 45 to cool the processed wafer W' while performing the purge process, without the need to transfer the processed wafer W' to other modules for cooling, thereby improving the overall wafer processing efficiency and preventing the processed wafer W' from being oxidized during the transfer process to affect the electrical properties.

[0075] The cooling disc 45 circulates cooling liquid, and has a cooling liquid inlet 451 and a cooling liquid outlet 452. The external cooling liquid enters the cooling disc 45 through the cooling liquid inlet 451 to cool the processed wafer W', and the cooling liquid with a high temperature flows out through the cooling liquid outlet 452. The temperature of the cooling liquid entering the cooling disc 45 is 0-50°C.

[0076] The cooling disc 45 is made of a material with good thermal conductivity, for example, stainless steel, aluminum plated nickel, ceramic, etc. The size of the cooling disc 45 is the same as that of the processed wafer W', and in other embodiments, the diameter of the cooling disc 45 is ±10 mm different from that of the processed wafer W'.

[0077] In order to improve the cooling effect of the cooling disc 45 on the processed wafer W', a driving device is arranged in the buffer cavity 40, which is connected with the lowermost support in the buffer cavity 40 and can drive the lowermost support to move downward and upward. After the processed wafer W' enters the buffer cavity 40 and is placed on the lowermost support, the driving device drives the lowermost support to move downward from the wafer transfer position, thereby driving the processed wafer W' to move downward until it is close to the cooling disc 45, so that the cooling effect of the cooling disc 45 on the processed wafer W' is better. After a set cooling time is reached, the driving device drives the lowermost support to move upward, thereby lifting the processed wafer W' until it is reset to the wafer transfer position.

[0078] When using the buffer device of this embodiment to transfer the processed wafer W', after placing the processed wafer W' on the lowest support and closing the first transfer door, before or simultaneously with the controller 43 adjusting the air pressure of the buffer cavity 40, coolant flows in the cooling tray 45. Then, the drive device drives the lowest support to move downwards close to the cooling tray 45, so that the cooling tray 45 cools the processed wafer W'. After the set cooling time is reached, the drive device drives the lowest support to move upwards and reset to the wafer transfer position. After the purging gas completes purging and the air pressure in the buffer cavity 40 is lower than that in the transfer cavity 50, the second transfer door is opened to transfer the cooled processed wafer W' to the transfer cavity 50.

[0079] In another embodiment, the buffer device includes two horizontally arranged buffer cavities, each having the same structure as in the above embodiment. This buffer device is suitable for dual-process-cavity structures. In semiconductor process platforms, two process cavities are configured for certain time-consuming process flows, allowing the two cavities to perform the same process simultaneously, thereby improving wafer processing efficiency. The two process cavities are arranged side-by-side at the same horizontal level and connected to the same transfer cavity, which is equipped with two robotic arms for transferring wafers from the two process cavities, respectively, to improve wafer transfer efficiency.

[0080] like Figure 6 and Figure 7 As shown, the first process cavity 31 and the second process cavity 32 are arranged side by side and are respectively connected to the first buffer cavity 46 and the second buffer cavity 47 arranged side by side. The first buffer cavity 46 and the second buffer cavity 47 have the same structure as the buffer cavity in the above embodiment. The first buffer cavity 46 and the second buffer cavity 47 are also connected to the transmission cavity 51.

[0081] The buffer device in this embodiment also includes a gas supply device 41, a vacuum device 42, and a controller 43. The difference from the buffer device in the previous embodiment is that the gas supply device 41 in this embodiment has a gas supply line 412 with three ports, connected to the first buffer chamber 46, the second buffer chamber 47, and the purge gas source 411, respectively. Thus, the purge gas source 411 is simultaneously connected to both the first and second buffer chambers 46 and 47, allowing both chambers to share the gas supply device 41. Similarly, the vacuum device 42 also has a vacuum line 422 with three ports, connected to the first and second buffer chambers 46 and the vacuum pump 421, respectively. Thus, the vacuum pump 421 is simultaneously connected to both the first and second buffer chambers 46 and 47, allowing both chambers to share the vacuum device 42. The controller 43 controls the operating states of the gas supply device 41 and the vacuum device 42, thereby simultaneously generating a high-speed purge airflow within the buffer chamber 40 to purge the wafer.

[0082] In other embodiments, a gate valve can also be provided on the exhaust line 422 and the supply line 412, respectively, to control one of the buffer chambers separately.

[0083] The first buffer chamber 46 and the second buffer chamber 47 each have double layers of vertically arranged racks 44 to store both processed wafers and unprocessed wafers, so that the buffer device can store and purge four wafers at most. In other embodiments, the first buffer chamber 46 and the second buffer chamber 47 can have more layers of racks 44 to further improve the overall processing efficiency of the process chamber.

[0084] Further, a cooling disc and a driving device can be provided in the first buffer chamber 46 and the second buffer chamber 47, respectively, to cool the processed wafers entering therein, thereby improving the wafer processing efficiency of the semiconductor process platform.

[0085] Although the content of the present application has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as limiting the present application. After reading the above content, various modifications and substitutions of the present application will be apparent to those skilled in the art. Therefore, the protection scope of the present application should be defined by the appended claims.

Claims

1. A buffer device disposed between a process chamber and a transfer chamber, characterized in that, The buffer device includes a buffer cavity through which wafers are transferred between the process cavity and the transfer cavity, the buffer device comprising: A gas supply device for supplying purge gas into the buffer chamber; A vacuum device is used to extract the purge gas from the buffer chamber. The controller is connected to the gas supply device and the pumping device respectively. The controller controls the gas supply device and the pumping device to work alternately to increase the gas pressure in the buffer chamber from the first gas pressure to the second gas pressure within a first preset time period, and decrease the gas pressure in the buffer chamber from the second gas pressure to the first gas pressure within a second preset time period.

2. The buffer device as described in claim 1, characterized in that, The controller controls the gas supply rate of the gas supply device and the pumping rate of the pumping device to increase the gas pressure in the buffer chamber from the first gas pressure to the second gas pressure within 10 seconds, and to decrease the gas pressure in the buffer chamber from the second gas pressure to the first gas pressure within 120 seconds.

3. The buffer device as described in claim 1, characterized in that, The buffer cavity also includes a support for placing the wafer, one end of which is connected to the inner side wall of the buffer cavity, and the other end extends into the interior of the buffer cavity.

4. The buffer device as described in claim 3, characterized in that, At least two layers of the support are arranged in the vertical direction.

5. The buffer device as described in claim 4, characterized in that, The lowest layer of the support is used to hold the wafers transferred from the process cavity to the transport cavity.

6. The buffer device as described in claim 5, characterized in that, The bottom of the buffer chamber is also provided with a cooling plate, and coolant flows through the cooling plate.

7. The buffer device as described in claim 6, characterized in that, The buffer cavity also includes a driving device connected to the bottommost support, which drives the bottommost support to move downward or upward, so that the bottommost support moves closer to the cooling plate or returns to its original position.

8. The buffer device as claimed in claim 1, characterized in that, The buffer device includes two buffer cavities, which are connected to the same transmission cavity, and each of the two buffer cavities is connected to a process cavity.

9. The buffer device as described in claim 1 or 2, characterized in that, The first air pressure is 0.01 Torr to 0.1 Torr, and the second air pressure is 1 Torr to 700 Torr.

10. The buffer device as claimed in claim 1, characterized in that, The gas supply device includes a mass flow controller connected to the controller, which controls the gas supply rate of the gas supply device by controlling the mass flow controller.

11. The buffer device as claimed in claim 1, characterized in that, The air extraction device includes an air extraction pump.

12. The buffer device as claimed in claim 11, characterized in that, The air pump is connected to the controller, and the controller controls the air pumping rate of the air pumping device by controlling the rotation speed of the air pump.

13. The buffer device as claimed in claim 11, characterized in that, The air pump is equipped with a throttle valve, which is connected to the controller. The controller controls the air pumping rate of the air pumping device by controlling the opening degree of the throttle valve.

14. The buffer device as claimed in claim 1, characterized in that, The buffer cavity has a first sidewall and a second sidewall. A first transmission gate is provided on the first sidewall, and a second transmission gate is provided on the second sidewall. The buffer cavity is connected to the process cavity through the first transmission gate, and the buffer cavity is connected to the transmission cavity through the second transmission gate.

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