Intracavity wafer centering system and working method thereof

Abstract

An in-cavity wafer centering system and a working method thereof, the in-cavity wafer centering system comprising: a main cavity; a wafer clamping platform located in the main cavity, a surface of the wafer clamping platform being adapted to place a wafer; a plurality of displacement holes penetrating through the wafer clamping platform; a plurality of ejectors respectively located in the displacement holes, the ejectors being adapted to reciprocate in the displacement holes, so that a top head of the ejectors changes between a position higher than an upper surface of the wafer clamping platform and a position lower than the upper surface of the wafer clamping platform; a plurality of optical positioning units, each optical positioning unit comprising: an optical detection component; an optical receiving component, the optical detection component being adapted to emit detection light to the optical receiving component, the detection light being adapted to partially irradiate an edge of the wafer in the main cavity; a correction unit, the correction unit being adapted to correct a position of the wafer according to light information obtained by the optical receiving component. The in-cavity wafer centering system can accurately position the wafer in the main cavity, and improve process repeatability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor manufacturing, and in particular to a cavity wafer centering system and a working method thereof. BACKGROUND

[0002] In semiconductor manufacturing, a plurality of processes are involved, each of which is completed by certain equipment and process. Among them, etching process is an important process in semiconductor manufacturing, such as plasma etching process. Plasma etching process is to generate plasma by using reaction gas after obtaining energy, including charged particles such as ions, electrons, and highly chemically active neutral atoms, molecules and free radicals, and to etch the etching object through physical and chemical reactions.

[0003] However, in the process of plasma etching, the etching conditions of the edge of the wafer and the etching conditions of the center of the wafer are quite different, including plasma density distribution, radio frequency electric field, temperature distribution, etc., so that in the process of etching the center area of the wafer, the by-product polymer will be deposited on the upper and lower surfaces and the sidewall of the edge of the wafer. The deposition of by-product polymer will have a cumulative effect as the etching process proceeds. When the thickness of the by-product polymer reaches a certain degree, the adhesion between the by-product polymer and the wafer will become poor, causing the by-product polymer to fall off, and further causing a series of problems such as affecting the pattern stability of the wafer and contaminating the etching chamber.

[0004] In view of this, the industry has introduced edge etching process. Specifically, the wafer is placed in an edge etching device, and the generated plasma etches the edge of the wafer while avoiding etching the center of the wafer as much as possible.

[0005] However, in the process of the existing edge etching process using the edge etching device, the repeatability of etching the edge area of the wafer is poor. SUMMARY

[0006] The problem solved by the present application is to provide a cavity wafer centering system and a working method thereof, which can accurately position the position of the wafer in the main cavity and improve the process repeatability.

[0007] To solve the above technical problems, the present application provides an in-cavity wafer centering system, comprising: a main cavity; a wafer clamping platform located in the main cavity, a surface of the wafer clamping platform being adapted to place a wafer; a plurality of displacement holes penetrating through the wafer clamping platform; a plurality of ejectors respectively located in the displacement holes, the ejectors being adapted to reciprocate in the displacement holes, so that a top head of the ejector changes between a position higher than an upper surface of the wafer clamping platform and a position lower than the upper surface of the wafer clamping platform; a plurality of optical positioning units, each optical positioning unit comprising: an optical detection component; an optical receiving component, the optical detection component being adapted to emit a detection light to the optical receiving component, the detection light being adapted to partially irradiate an edge of the wafer in the main cavity; a correction unit, the correction unit being adapted to correct a position of the wafer according to light information obtained by the optical receiving component.

[0008] Optionally, the in-cavity wafer centering system further comprises: an ejector position adjusting member located at a bottom of the wafer clamping platform, the ejector position adjusting member being in contact with a bottom end of the ejector.

[0009] Optionally, in the in-cavity wafer centering system, the number of the displacement holes is at least three, and the number of the ejectors is at least three.

[0010] Optionally, in the in-cavity wafer centering system, the number of the plurality of optical positioning units is at least three.

[0011] Optionally, in the in-cavity wafer centering system, the number of the plurality of optical positioning units is four, and the four optical positioning units are uniformly distributed around a central axis of the wafer clamping platform.

[0012] Optionally, the in-cavity wafer centering system is an edge etching reaction device; the in-cavity wafer centering system further comprises: a movable upper electrode located in the main cavity, the movable upper electrode being oppositely arranged with the wafer clamping platform; a radio frequency isolation ring located in the main cavity and located at a side of the wafer clamping platform; a plasma confinement ring located in the main cavity, the plasma confinement ring being located at a bottom of an edge region of the movable upper electrode, the plasma confinement ring and the radio frequency isolation ring having a gap therebetween; a plurality of first detection channels penetrating through a top wall of the main cavity and the edge region of the movable upper electrode, a distance from the first detection channels to a center of the movable upper electrode being smaller than a distance from the plasma confinement ring to the center of the movable upper electrode; a plurality of second detection channels located at a bottom of the first detection channels and corresponding to the first detection channels one by one, the second detection channels being located in the radio frequency isolation ring; the optical detection component being located above the first detection channels and covering part of a top surface of the main cavity; the optical receiving component being located in the main cavity and below the second detection channels.

[0013] Optionally, the movable upper electrode has a groove through the thickness of the movable upper electrode on the side of the wafer clamping platform; the in-cavity wafer centering system further comprises: a wafer protection disc in the groove; a first gas inlet channel through the movable upper electrode, with the outlet of the first gas inlet channel on the bottom surface of the movable upper electrode on the side of the wafer protection disc, the first gas inlet channel being used for introducing etching gas; and a second gas inlet channel through the movable upper electrode and the wafer protection disc, the second gas inlet channel being used for introducing buffer gas.

[0014] The application further provides a working method of an in-cavity wafer centering system, comprising: calibrating the positions of the optical positioning units; after the positions of the optical positioning units are calibrated, moving the thimble in the displacement hole so that the tip of the thimble is higher than the upper surface of the wafer clamping platform; after the tip of the thimble is higher than the upper surface of the wafer clamping platform, placing a wafer on the thimble; after the wafer is placed on the thimble, the optical detection component emits detection light to the optical receiving component, part of the detection light irradiates the edge of the wafer, and the optical receiving component acquires light information of the wafer; for the wafer placed on the thimble, the correction unit corrects the position of the wafer according to the light information of the wafer acquired by the optical receiving component; after the correction unit corrects the position of the wafer according to the light information of the wafer placed on the thimble acquired by the optical receiving component, the thimble moves downward so that the wafer falls on the upper surface of the wafer clamping platform; during the process that the thimble moves downward so that the wafer falls on the upper surface of the wafer clamping platform, the optical positioning units monitor the position of the wafer in real time.

[0015] Optionally, the method of calibrating the positions of the optical positioning units comprises: providing a calibration wafer; placing the calibration wafer on the surface of the wafer clamping platform; performing a flow test on the calibration wafer until the distance between the center of the calibration wafer and the central axis of the wafer clamping platform meets a first threshold value; after the distance between the center of the calibration wafer and the central axis of the wafer clamping platform meets the first threshold value, adjusting the positions of the optical positioning units so that the optical receiving component acquires light information of the calibration wafer that meets positioning requirements.

[0016] Compared with the prior art, the technical scheme of the application has the following beneficial effects:

[0017] The cavity wafer centering system provided by the technical scheme has a plurality of displacement holes penetrating through the wafer clamping platform, the displacement holes have a thimble, the thimble is adapted to reciprocate in the displacement hole, the top head of the thimble changes between a position higher than the upper surface of the wafer clamping platform and a position lower than the upper surface of the wafer clamping platform, so that the thimble can lift the wafer from the wafer clamping platform or drop the wafer on the surface of the wafer clamping platform. The cavity wafer centering system also has a plurality of optical positioning units, each optical positioning unit includes: an optical detection component; an optical receiving component, the optical detection component is adapted to emit detection light to the optical receiving component, the detection light is adapted to partially irradiate the edge of the wafer in the main cavity; a correction unit, the correction unit is adapted to correct the position of the wafer according to the light information obtained by the optical receiving component. The plurality of optical positioning units can monitor the position of the wafer on the thimble and adjust and correct the position of the wafer in real time, so that the position of the wafer meets the requirements of the process. In this way, through the monitoring of the wafer position by the optical detection component and the optical receiving component and the correction of the wafer position by the correction unit, the positions of a plurality of wafers in the main cavity remain basically consistent during the process of sequentially performing the process on the plurality of wafers, the cavity wafer centering system can accurately position and correct the position of the wafer in the main cavity, and the repeatability of the process is greatly improved.

[0018] Further, the cavity wafer centering system is an edge etching reaction device, the plasma confinement ring is located at the bottom of the edge region of the movable upper electrode, there is a gap between the plasma confinement ring and the radio frequency isolation ring, and the plasma confinement ring is used to limit the distribution of plasma. The wafer clamping platform is used to clamp the wafer. Radio frequency is fed from the wafer clamping platform to charge the wafer. The region between the wafer clamping platform and the plasma confinement ring is plasma discharged to etch the edge of the wafer. Etching gas is blown to the vicinity of the edge of the wafer through the edge of the movable upper electrode, and then ionized by radio frequency to generate plasma, so as to realize etching of the deposition on the edge of the wafer. The new edge etching reaction device can ensure that the plasma is uniformly and stably distributed between the upper electrode edge conductive electrode-wafer-electrostatic chuck, can and only can etch the reaction in a specific size range of the edge region of the wafer, and the center region of the wafer is not affected. In summary, the etching precision of the edge region of the wafer is improved. Secondly, the etching efficiency of the edge region of the wafer is also improved. Thirdly, through the monitoring of the wafer position by the optical detection component and the optical receiving component and the correction of the wafer position by the correction unit, the positions of a plurality of wafers in the main cavity remain basically consistent during the process of sequentially etching the plurality of wafers, the cavity wafer centering system can accurately position and correct the position of the wafer in the main cavity, and the repeatability of the edge etching effect of the wafer is greatly improved.

[0019] In the working method of the intracavity wafer centering system provided by the present invention, after calibrating the positions of the plurality of optical positioning units, the ejector pin moves in the displacement hole so that the tip of the ejector pin is higher than the upper surface of the wafer clamping platform. Then, the wafer is placed on the ejector pin. Next, the optical detection component emits detection light to the optical receiving component, and part of the detection light illuminates the edge of the wafer. The optical receiving component acquires light information about the wafer. For the wafer placed on the ejector pin, the correction unit corrects the position of the wafer based on the light information acquired by the optical receiving component, ensuring that the position of the wafer on the ejector pin meets the process requirements. After the correction unit corrects the position of the wafer based on the light information acquired by the optical receiving component, the ejector pin moves downward so that the wafer falls onto the upper surface of the wafer clamping platform. During this process, the plurality of optical positioning units monitor the position of the wafer in real time to ensure that the position of the wafer does not deviate significantly during the downward movement of the ejector pin and meets the process requirements. By monitoring the wafer position through optical detection and optical receiving components, and correcting the wafer position through correction units, the positions of multiple wafers in the main cavity remain basically consistent during the sequential processing of multiple wafers. The in-cavity wafer centering system can accurately locate and correct the wafer position in the main cavity, greatly improving the repeatability of the process. Attached Figure Description

[0020] Figure 1 This is a schematic cross-sectional view of the intracavity wafer centering system in one embodiment of the present invention;

[0021] Figure 2 This is a top-view schematic diagram of the positions of the wafer and the optical receiving component in one embodiment of the present invention;

[0022] Figure 3 This is a flowchart illustrating the operation of the intracavity wafer centering system in another embodiment of the present invention. Detailed Implementation

[0023] One embodiment of the present invention provides an intracavity wafer centering system, please refer to... Figure 1 and Figure 2 ,include:

[0024] Main cavity;

[0025] A wafer clamping platform 110 is located within the main cavity, and the surface of the wafer clamping platform 110 is adapted to place a wafer 10.

[0026] A plurality of displacement holes penetrating the wafer clamping platform 110;

[0027] a plurality of displacement holes, each of the displacement holes being adapted to receive a respective one of a plurality of pins 170, the plurality of pins 170 being adapted to reciprocate in the plurality of displacement holes, such that a tip of the plurality of pins 170 moves between a position above an upper surface of the wafer holding platform 110 and a position below the upper surface of the wafer holding platform 110;

[0028] a plurality of optical positioning units, each of the optical positioning units comprising: an optical detecting component 200, the optical detecting component 200 being adapted to emit detecting light to an optical receiving component 230, the detecting light being adapted to partially irradiate an edge of the wafer 10 in the main cavity; a correction unit, the correction unit being adapted to correct a position of the wafer 10 according to light information obtained by the optical receiving component 230.

[0029] In the embodiment, the in-cavity wafer centering system is an edge etching reaction device. In other embodiments, the in-cavity wafer centering system can also be other deposition devices or etching devices.

[0030] The in-cavity wafer centering system further comprises a pin position adjusting member 180 located at a bottom of the wafer holding platform 110, the pin position adjusting member 180 being in contact with a bottom end of the pin 170.

[0031] In one embodiment, in an in-cavity wafer centering system, the number of the displacement holes is at least three, and the number of the pins 170 is at least three. The number of the pins 170 is equal to the number of the displacement holes, and one pin 170 is placed in one displacement hole. It should be noted that in other embodiments, the number of the pins 170 in an in-cavity wafer centering system can also be one, two, or more than three. When the number of the displacement holes in an in-cavity wafer centering system is at least three, the position stability of the wafer 10 on the pins 170 is better.

[0032] The height of the pin 170 is greater than the thickness of the wafer holding platform 110, and the height of the pin 170 is the distance between the tip of the pin 170 and the bottom end of the pin 170.

[0033] The material of the pin 170 comprises stainless steel, aluminum alloy, ceramic, or quartz.

[0034] In one embodiment, in an in-cavity wafer centering system, the number of the plurality of optical positioning units is at least three, so that the plurality of optical positioning units can better monitor the position of the wafer 10.

[0035] In the embodiment, in an in-cavity wafer centering system, the number of the plurality of optical positioning units is four, and the four optical positioning units are uniformly distributed around the central axis of the wafer holding platform 110.

[0036] In other embodiments, the number of optical positioning units in an in-cavity wafer centering system is greater than four.

[0037] It should be noted that an optical positioning unit includes an optical detection component 200 and an optical receiving component 230.

[0038] The optical detection component 200 can be a laser generator. The optical receiving component 230 can be a photoelectric converter.

[0039] In this embodiment, the in-cavity wafer centering system is an edge etching reaction device, and accordingly, the in-cavity wafer centering system further includes a movable upper electrode 100 located in the main cavity, the movable upper electrode 100 and the wafer clamping platform 110 are oppositely arranged; a radio frequency isolation ring 130 located in the main cavity and located at the side of the wafer clamping platform 110; a plasma confinement ring 140 located in the main cavity, the plasma confinement ring 140 is located at the bottom of the edge region of the movable upper electrode 100, and the plasma confinement ring 140 and the radio frequency isolation ring 130 have a gap therebetween.

[0040] The side of the movable upper electrode 100 facing the wafer clamping platform 110 has a groove penetrating a portion of the thickness of the movable upper electrode 100. The in-cavity wafer centering system further includes a wafer protection disc 120 located in the groove.

[0041] In this embodiment, the plasma confinement ring 140 is located between the edge region of the movable upper electrode 100 and the radio frequency isolation ring 130. In other embodiments, the plasma confinement ring is located at the bottom of the edge region of the movable upper electrode, and the bottom region in the plasma confinement ring is located outside the radio frequency isolation ring 130. It should be noted that the radio frequency isolation ring can also extend to the bottom of the wafer clamping platform.

[0042] In this embodiment, the in-cavity wafer centering system further includes a plurality of first detection channels 210 penetrating the top wall of the main cavity and the edge region of the movable upper electrode 100, the distance from the first detection channel 210 to the center of the movable upper electrode 100 is less than the distance from the plasma confinement ring 140 to the center of the movable upper electrode 100; a second detection channel 220 located at the bottom of the first detection channel 210 and corresponding to the first detection channel 210 one by one, the second detection channel 220 is located in the radio frequency isolation ring 130.

[0043] The optical detecting component 200 is located above the first detecting channel 210 and covers part of the top surface of the main cavity, and the optical receiving component 230 is located in the main cavity and below the second detecting channel 220. In this embodiment, the optical receiving component 230 is located in the radio frequency isolation ring 130 below the second detecting channel 220.

[0044] The central axis of the first detecting channel 210 is adapted to coincide with the central axis of the second detecting channel 220.

[0045] In this embodiment, the radio frequency isolation ring 130 covers part of the sidewall of the wafer clamping platform 110; the in-cavity wafer centering system further comprises a wafer clamping platform protection ring 190 located on part of the upper surface of the radio frequency isolation ring 130 and in contact with part of the side of the wafer clamping platform 110.

[0046] In this embodiment, the plasma confinement ring 140 is in contact with the edge bottom of the movable upper electrode 100, and specifically, the plasma confinement ring 140 is in effective electrical connection or electrically insulated connection with the edge bottom of the movable upper electrode 100. When the plasma confinement ring 140 is in effective electrical connection with the edge bottom of the movable upper electrode 100, the plasma confinement ring 140 not only plays a role in physically confining the plasma, but also plays a role in electrically confining the plasma. When the plasma confinement ring 140 is in effective electrical connection with the edge bottom of the movable upper electrode 100, the plasma confinement ring 140 is an aluminum alloy annular metal piece, a silicon annular piece, or a silicon carbide annular piece, and the potential of the plasma confinement ring 140 is consistent with that of the movable upper electrode 100. When the plasma confinement ring 140 is in electrically insulated connection with the edge bottom of the movable upper electrode 100, the plasma confinement ring 140 is a ceramic annular piece or a quartz annular piece. In one embodiment, the plasma confinement ring is in non-contact with the edge bottom of the movable upper electrode, and correspondingly, the plasma confinement ring is an aluminum alloy annular metal piece, a silicon annular piece, or a silicon carbide annular piece, a ceramic annular piece, or a quartz annular piece. Further, when the plasma confinement ring is an aluminum alloy annular metal piece, the inner surface of the plasma confinement ring has a protective layer, and the material of the protective layer is aluminum oxide or Y2O3. The protective layer can prolong the service life of the plasma confinement ring 140.

[0047] The plasma confinement ring 140 has a gas extraction channel therein; the area surrounded by the movable upper electrode, the radio frequency isolation ring, and the plasma confinement ring on the side of the wafer protection disc is a plasma area; the size of the gas extraction channel is designed such that the minimum distance of the charged particles in the plasma area from moving away from the gas extraction channel is greater than the average free path of the charged particles.

[0048] In other embodiments, the plasma confinement ring is a solid structure, and etching reaction byproducts are extracted with a gap between the plasma confinement ring and the RF isolation ring.

[0049] In this embodiment, the plasma confinement ring surrounds the wafer chucking platform, and surrounds the wafer during etching of the wafer.

[0050] In this embodiment, the in-cavity wafer centering system further comprises: a first gas inlet channel 150, the first gas inlet channel 150 passing through the movable upper electrode 100, and the outlet of the first gas inlet channel 150 being located at the bottom surface of the movable upper electrode 100 at the side of the wafer protection disc 120, the first gas inlet channel 150 being used for introducing etching gas; and a second gas inlet channel 160 penetrating through the movable upper electrode 100 and the wafer protection disc 120, the second gas inlet channel 160 being used for introducing buffer gas.

[0051] The etching gas comprises any one or more of a combination of oxygen-containing gas and related fluorine-containing gas. The fluorine-containing gas comprises fluorocarbon-based gas, for example, CF4. The oxygen-containing gas comprises oxygen. The buffer gas comprises inert gas.

[0052] Correspondingly, the embodiment also provides a working method of an in-cavity wafer centering system (refer to Figure 1 and Figure 2 ), comprising the following steps:

[0053] S01: calibrating the positions of the optical positioning units;

[0054] S02: after calibrating the positions of the optical positioning units, moving the thimble 170 in the displacement hole so that the top head of the thimble 170 is higher than the upper surface of the wafer chucking platform 110;

[0055] S03: after the top head of the thimble 170 is higher than the upper surface of the wafer chucking platform 110, placing a wafer 10 on the thimble 170;

[0056] S04: after placing the wafer 10 on the thimble 170, the optical detection component 200 emits detection light to the optical receiving component 230, part of the detection light irradiating the edge of the wafer 10, and the optical receiving component 230 acquiring light information of the wafer 10;

[0057] S05: for the wafer 10 placed on the thimble 170, the correction unit corrects the position of the wafer 10 according to the light information of the wafer acquired by the optical receiving component 230;

[0058] S06: After the position of the wafer 10 is corrected by the correction unit according to the light information acquired by the optical receiving component 230 for the wafer 10 placed on the probe pin 170, the probe pin 170 moves downward so that the wafer 10 falls on the upper surface of the wafer clamping platform 110.

[0059] S07: During the process that the probe pin 170 moves downward so that the wafer 10 falls on the upper surface of the wafer clamping platform 110, the positions of the wafer 10 are monitored in real time by the plurality of optical positioning units.

[0060] The method for calibrating the positions of the plurality of optical positioning units comprises: providing a calibration wafer; placing the calibration wafer on the surface of the wafer clamping platform 110; performing a flow test on the calibration wafer until the distance from the center of the calibration wafer to the central axis of the wafer clamping platform 110 satisfies a first threshold value; after the distance from the center of the calibration wafer to the central axis of the wafer clamping platform 110 satisfies the first threshold value, adjusting the positions of the respective optical positioning units so that the optical receiving component acquires light information that satisfies the positioning requirements for the calibration wafer.

[0061] In one embodiment, after the calibration wafer is placed on the surface of the wafer clamping platform 110, a polymer is deposited in the edge region of the calibration wafer; the lateral size of the polymer in the edge region of the calibration wafer is tested; according to the difference in the lateral size of the polymer in the edge region of the calibration wafer, the position of the calibration wafer placed on the surface of the wafer clamping platform 110 is adjusted until the difference in the lateral size of the polymer in the edge region of the calibration wafer satisfies a threshold range. When the difference in the lateral size of the polymer in the edge region of the calibration wafer satisfies the threshold range, it means that the distance from the center of the calibration wafer to the central axis of the wafer clamping platform 110 satisfies the first threshold value. It should be noted that during the process of depositing the polymer in the edge region of the calibration wafer, the distance between the movable upper electrode 100 and the calibration wafer is kept at a small distance, so that the polymer is not deposited in the center region of the wafer, but only in the edge region of the wafer.

[0062] In another embodiment, before the calibration wafer is placed on the surface of the wafer clamping platform 110, the calibration wafer has a layer of to-be-etched layer on the front surface; after the calibration wafer is placed on the surface of the wafer clamping platform 110, an edge etching process is performed on the calibration wafer to form etching grooves in the edge region of the to-be-etched layer; the transverse size of the etching grooves is tested; according to the difference of the transverse size of the etching grooves at different positions, the position of the calibration wafer placed on the surface of the wafer clamping platform 110 is adjusted until the difference of the transverse size of the etching grooves at different positions meets a threshold range; when the difference of the transverse size of the etching grooves at different positions meets the threshold range, it means that the distance from the center of the calibration wafer to the central axis of the wafer clamping platform 110 meets a first threshold. It should be noted that during the edge etching process of the calibration wafer, the distance between the movable upper electrode 100 and the calibration wafer is kept at a small distance, and only the edge region of the calibration wafer is etched, and the central region of the calibration wafer is not etched.

[0063] The four optical detection components are a first detection component, a second detection component, a third detection component, and a fourth detection component, and the four optical receiving components are a first receiving component 230A, a second receiving component 230B, a third receiving component 230C, and a fourth receiving component 230D.

[0064] When there is no wafer or calibration wafer blocking, the first detection component emits detection light, the light intensity received by the first receiving component 230A is B10, the second detection component emits detection light, the light intensity received by the second receiving component 230B is B20, the third detection component emits detection light, the light intensity received by the third receiving component 230C is B30, and the fourth detection component emits detection light, the light intensity received by the fourth receiving component 230D is B40.

[0065] After the distance from the center of the calibration wafer to the center axis of the wafer clamping platform 110 meets the first threshold value, the positions of the respective optical positioning units are adjusted so that the optical receiving components obtain light information from the calibration wafer that meets positioning requirements. Specifically, the positions of the respective optical positioning units are fine-tuned so that the positions of the probe light spots emitted by the first, second, third, and fourth probe components meet the following conditions: the light spot line of the probe light emitted by the first probe component coincides with the first mark line groove of the calibration wafer, the light spot line of the probe light emitted by the second probe component coincides with the second mark line groove of the calibration wafer, the light spot line of the probe light emitted by the third probe component coincides with the third mark line groove of the calibration wafer, and the light spot line of the probe light emitted by the fourth probe component coincides with the fourth mark line groove of the calibration wafer. The light intensity measured by the first receiving component is a set target light intensity, for example, 50% B10, the light intensity measured by the second receiving component is a set target light intensity, for example, 50% B20, the light intensity measured by the third receiving component is a set target light intensity, for example, 50% B30, and the light intensity measured by the fourth receiving component is a set target light intensity, for example, 50% B40. At this time, the position calibration requirements for the optical positioning units are met.

[0066] After the wafer 10 is placed on the probe pin 170, the optical detection component 200 emits detection light to the optical receiving component 230, the detection light partially irradiates the edge of the wafer 10, and the optical receiving component 230 acquires light information of the wafer 10; for the wafer 10 placed on the probe pin 170, the correction unit corrects the position of the wafer 10 according to the light information acquired by the optical receiving component 230 for the wafer. Specifically, at the initial moment when the wafer is placed on the probe pin 170, the initial position of the wafer can be a central deviation state. Assuming that the light intensity received by the first receiving component (corresponding to the non-marked gap of the wafer) is 30% B10, the light intensity received by the second receiving component (corresponding to the non-marked gap of the wafer) is 80% B20, the light intensity received by the third receiving component (corresponding to the non-marked gap of the wafer) is 70% B30, and the light intensity received by the fourth receiving component (corresponding to the non-marked gap of the wafer) is 20% B40, it indicates that the initial position of the wafer deviates from the calibration center point to the fourth quadrant; this deviation information will be fed back to the correction system, and the correction unit adjusts the position of the wafer 10 according to the light information received by the first receiving component, the second receiving component, the third receiving component and the fourth receiving component, until the light intensity received by the first receiving component 230A (corresponding to the non-marked gap of the wafer) is (50±1)% B10, the light intensity received by the second receiving component 230B (corresponding to the non-marked gap of the wafer) is (50±1)% B20, the light intensity received by the third receiving component 230C (corresponding to the non-marked gap of the wafer) is (50±1)% B30, and the light intensity received by the fourth receiving component 230D (corresponding to the non-marked gap of the wafer) is (50±1)% B40. Through continuous correction, the center point positioning of the wafer is finally completed, and the positioning accuracy and repeatability are improved.

[0067] In this embodiment, the extremely narrow linear light spot G of the detection light is emitted, the width of the light spot G is within 50 microns, the length of the light spot reaches mm level and is less than 2 times the size of the mark gap of the wafer, for example, the length of the light spot can reach 2 mm. The light spot of the detection light can also be elliptical or circular.

[0068] In the process of the movement of the ejector pin 170 downwardly so that the wafer 10 falls on the upper surface of the wafer clamping platform 110, the optical positioning units monitor the position of the wafer 10 in real time. In this process, in order to prevent the phenomenon of the wafer slide eccentricity when the wafer moves up and down, the optical positioning units monitor the position of the wafer 10 in real time, and when the wafer completely falls on the upper surface of the wafer clamping platform 110, the change of the light spot intensity received by the four optical receiving components still satisfies: the light intensity received by the first receiving component 230A (corresponding to the non-marked gap of the wafer) is (50±1)% B10, the light intensity received by the second receiving component 230B (corresponding to the non-marked gap of the wafer) is (50±1)% B20, the light intensity received by the third receiving component 230C (corresponding to the non-marked gap of the wafer) is (50±1)% B30, and the light intensity received by the fourth receiving component 230D (corresponding to the non-marked gap of the wafer) is (50±1)% B40.

[0069] At this point, the whole wafer centering process is completed.

[0070] Then, the distance between the movable upper electrode 100 and the wafer clamping platform 110 is adjusted to be within a threshold range, for example, so that the distance between the wafer and the wafer protection disc 120 is less than 1 mm, such as 0.5 mm. After adjusting the distance between the movable upper electrode 100 and the wafer clamping platform 110, the etching gas is introduced through the first gas inlet channel 150, the buffer gas is introduced through the second gas inlet channel 160, and the radio frequency power is loaded to ignite the plasma to start etching the edge of the wafer.

[0071] In the etching process, the etching gas is introduced through the first gas inlet channel 150, and the buffer gas is introduced through the second gas inlet channel 160. The advantage of this is that the etching gas introduced through the first gas inlet channel 150 etches the edge region of the wafer, while the inert gas introduced through the second gas inlet channel 160 enters the plasma generation zone, and the inert gas and the etching gas mixed in the plasma generation zone help the process of plasma discharge, and secondly, part of the inert gas enters the main cavity along the radial direction of the wafer, which can block the outward movement of the plasma.

[0072] Although the present application is disclosed as above, the present application is not limited to this. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be subject to the range defined by the claims.

Claims

1. An in-cavity wafer centering system, comprising: The cavity wafer centering system is an edge etching reaction device, comprising: a main cavity; a wafer clamping platform in the main cavity, a surface of the wafer clamping platform being suitable for placing a wafer; and a plurality of displacement holes penetrating through the wafer clamping platform; a plurality of ejectors respectively in the displacement holes, the ejectors being suitable for reciprocating in the displacement holes, so that a top head of the ejector changes between a position higher than an upper surface of the wafer clamping platform and a position lower than the upper surface of the wafer clamping platform, wherein the ejector can lift the wafer from the wafer clamping platform or drop the wafer on the surface of the wafer clamping platform; a plurality of optical positioning units, each optical positioning unit comprising: an optical detection component; and an optical receiving component, the optical detection component being suitable for emitting detection light to the optical receiving component, the detection light being suitable for partially irradiating an edge of the wafer in the main cavity, the plurality of optical positioning units being capable of monitoring the position of the wafer on the ejector and adjusting and correcting the position of the wafer in real time, so that the position of the wafer meets the requirements of a process; and a correction unit, the correction unit being suitable for correcting the position of the wafer according to light information obtained by the optical receiving component; through the monitoring of the wafer position by the optical detection component and the optical receiving component and the correction of the wafer position by the correction unit, the positions of a plurality of wafers in the main cavity remain substantially consistent in the process of sequentially performing a plurality of processes on the wafers, and the cavity wafer centering system is capable of accurately positioning and correcting the position of the wafer in the main cavity; an ejector position adjusting member at the bottom of the wafer clamping platform, the ejector position adjusting member being in contact with the bottom end of the ejector; in one cavity wafer centering system, the number of the plurality of optical positioning units is at least three, so that the plurality of optical positioning units can monitor the position of the wafer; a radio frequency isolation ring in the main cavity and located at the side of the wafer clamping platform, the radio frequency isolation ring covering part of the side wall of the wafer clamping platform; the cavity wafer centering system further comprises: a wafer clamping platform protection ring located on part of the upper surface of the radio frequency isolation ring and in contact with part of the side of the wafer clamping platform; a movable upper electrode in the main cavity, the movable upper electrode being oppositely arranged with the wafer clamping platform; a plasma confinement ring in the main cavity, the plasma confinement ring being located at the bottom of the edge region of the movable upper electrode, and the plasma confinement ring having a gap with the radio frequency isolation ring; a plurality of first detection channels penetrating through the top wall of the main cavity and the edge region of the movable upper electrode, the distance from the first detection channels to the center of the movable upper electrode being smaller than the distance from the plasma confinement ring to the center of the movable upper electrode; a second detection channel at the bottom of the first detection channel and corresponding to the first detection channel one by one, the second detection channel being located in the radio frequency isolation ring; the optical detection component being located above the first detection channel and covering part of the top surface of the main cavity; and the optical receiving component being located in the main cavity and below the second detection channel.

2. The in-cavity wafer centering system of claim 1, wherein, In an in-cavity wafer centering system, the number of displacement holes is at least three, and the number of the pins is at least three.

3. The intracavity wafer centering system of claim 1, wherein Further comprising: The movable upper electrode has a groove through the thickness of the movable upper electrode on the side of the wafer clamping platform; the in-cavity wafer centering system further comprises: a wafer protection disc in the groove; a first gas inlet channel passing through the movable upper electrode, and the outlet of the first gas inlet channel is located on the bottom surface of the movable upper electrode on the side of the wafer protection disc, and the first gas inlet channel is used for introducing etching gas; a second gas inlet channel passing through the movable upper electrode and the wafer protection disc, and the second gas inlet channel is used for introducing buffer gas.

4. A method of operating a bore-in-wafer centering system as claimed in any one of claims 1 to 3, characterized in that, Further comprising: Calibrating the positions of the optical positioning units; After calibrating the positions of the optical positioning units, the pins are moved in the displacement holes so that the heads of the pins are higher than the upper surface of the wafer clamping platform; after the heads of the pins are higher than the upper surface of the wafer clamping platform, a wafer is placed on the pins; After placing the wafer on the pins, the optical detection component emits detection light to the optical receiving component, and the detection light is partially irradiated on the edge of the wafer, and the optical receiving component acquires light information of the wafer; For the wafer placed on the pins, the correction unit corrects the position of the wafer according to the light information of the wafer acquired by the optical receiving component; After the correction unit corrects the position of the wafer according to the light information of the wafer placed on the pins acquired by the optical receiving component, the pins are moved downward so that the wafer falls on the upper surface of the wafer clamping platform; During the process that the pins are moved downward so that the wafer falls on the upper surface of the wafer clamping platform, the optical positioning units monitor the position of the wafer in real time.

5. The method of claim 4, wherein the method further comprises: The method for calibrating the positions of the optical positioning units comprises: providing a calibration wafer; placing the calibration wafer on the surface of the wafer clamping platform; performing a flow test on the calibration wafer until the distance between the center of the calibration wafer and the center axis of the wafer clamping platform meets a first threshold value; after the distance between the center of the calibration wafer and the center axis of the wafer clamping platform meets the first threshold value, adjusting the positions of the optical positioning units so that the optical receiving component acquires light information of the calibration wafer that meets positioning requirements.

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