Method for simultaneously performing ion implantation process on multiple wafers
By arranging multiple target disks on the scanning robot, multiple wafers are simultaneously implanted, which solves the problem that microcontrollers are difficult to improve ion implantation efficiency, significantly improves production capacity and wafer temperature control, and realizes a highly efficient and low-damage ion implantation process.
Patent Information
- Application Number
- CN202510079419.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-18
- Publication Date
- 2025-04-25
AI Technical Summary
Existing microcontrollers are difficult to further improve the efficiency of ion implantation process, especially in terms of increasing yield and improving temperature control.
The process method of ion implantation of multiple wafers simultaneously is adopted. By arranging multiple target disks on the scanning robot, the simultaneous holding and scanning injection of multiple wafers is achieved, and the processing time of each wafer is shortened.
It significantly improves production capacity, improves wafer hourly output (WPH), reduces lattice damage and temperature control difficulty, and does not need to change the entire beam system, making it easy to transform on the basis of existing microcontrollers.
Smart Images
Figure CN119890034A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a method for simultaneously performing an ion implantation process on multiple wafers. Background Art
[0002] At present, the main challenges facing ion implantation include temperature control and yield improvement. Compared with disk implantation (an earlier type of equipment, the basic structure is to distribute multiple wafers on a large disk. After one ion implantation, all wafers on the large disk are implanted), the single-chip microcomputer (i.e., a device that implants only one wafer each time) has better transmission stability, lower suspended particles, better uniformity and angle distribution, but if you want to increase the yield or improve the temperature, the single-chip microcomputer will be subject to certain limitations. Therefore, a more efficient ion implantation process is needed while ensuring process quality. Summary of the invention
[0003] Based on the technical problems existing in the prior art, the present invention provides a method for simultaneously performing ion implantation process on multiple wafers, which solves the problem that it is difficult for existing single-chip microcomputers to further improve the efficiency of the ion implantation process. By adopting the method of simultaneously implanting multiple wafers, the production capacity can be significantly improved, which is particularly suitable for example 150mm wafers.
[0004] According to the technical solution of the present invention, the present invention provides a method for simultaneously performing an ion implantation process on multiple wafers, wherein the ion implantation equipment used in the method has a scanning robot, and more than two target disks are arranged on the scanning robot;
[0005] The method for simultaneously performing ion implantation on multiple wafers comprises the following steps:
[0006] Step S1, the initial state is that the multiple target plates on the scanning robot are all flat and empty; then the wafers are transferred and placed on the target plates respectively, so that a wafer is placed on each target plate;
[0007] Step S2, the scanning robot controls the target plate to hold the wafers, and then flips them so that the multiple wafers are erected to the angle required by the process;
[0008] Step S3, performing a scanning process of ion implantation on the wafer; wherein the scanning area of the ion beam can completely cover the multiple wafers located on the scanning robot;
[0009] Step S4, after completing the ion implantation required for the process, the scanning robot returns to the initial flat state, waiting for the wafer on it to be removed;
[0010] Steps S1 to S4 are repeated until the ion implantation is completed for all the required number of wafers.
[0011] Furthermore, three or four target disks are arranged on the scanning robot, and the target disks are arranged regularly and aligned with each other or arranged staggered with each other.
[0012] According to some embodiments, the scanning robot is provided with four target disks, which are distributed in a quadrilateral, and two of the target disks are arranged side by side along the scanning direction.
[0013] Furthermore, the four target disks are distributed in a rectangular shape.
[0014] According to some further embodiments, the scanning robot is provided with three target disks, and the three target disks are distributed in a triangle shape.
[0015] Furthermore, the three target plates are distributed in the form of an isosceles triangle or an equilateral triangle, and two of them are arranged side by side along the scanning direction.
[0016] Furthermore, the ion beam is a ribbon beam, and the length of the cross-sectional shape of the ion beam is not less than twice the diameter of the wafer.
[0017] Furthermore, the ion implantation device used therein has a loading chamber and a transfer robot, the transfer robot is used to transfer the wafer between the loading chamber and the target plate; one or more baffles are contained in the loading chamber;
[0018] In the case where ion implantation is required for wafers less than the number of target plates, in step S1, baffles are used as wafer substitutes to be transferred and placed on the target plates, so that a wafer or a baffle is placed on each target plate.
[0019] Furthermore, in step S3, during the scanning process, each scan causes the ion beam to completely scan all wafers.
[0020] Furthermore, the ion beam used for ion implantation in the ion implantation device is a ribbon-shaped beam with a flat cross-section;
[0021] In the initial state described in step S1, the ion beam passes over the target disk;
[0022] After flipping in step S2, all wafers are located under the ion beam;
[0023] When ion implantation is performed in step S3, the scanning robot controls the target plate to move upward or diagonally upward, so that the ion beam completely scans all wafers and moves a certain overscan distance, thus completing one scan; the next scan is the process in which the scanning robot controls the target plate to move downward or diagonally downward, and after the scan, all wafers are located below the ion beam; the up and down scans are repeated in this way.
[0024] Compared with the prior art, the method of the present invention for simultaneously performing ion implantation process on multiple wafers has the following beneficial technical effects:
[0025] 1. The method of simultaneously performing ion implantation on multiple wafers of the present invention has multiple target plates on the scanning robot, so that multiple wafers can be held simultaneously for scanning implantation; the scanning process of ion implantation requires a certain amount of overscanning to ensure the integrity of the entire implantation, and for the scheme of scanning multiple wafers simultaneously, only one overscanning distance is required, so the average processing time of each wafer can be effectively shortened; for example, the ion beam is about 300 mm wide, and when processing a 150 mm wafer, up to four wafers can be placed and implanted simultaneously, thereby greatly improving production capacity.
[0026] 2. Compared with the existing process methods, the method of the present invention for simultaneously performing ion implantation process on multiple wafers can comprehensively improve WPH (wafer output per hour) without affecting the process results and the safe and reliable operation of the equipment.
[0027] 3. In the method of the present invention for simultaneously performing ion implantation process on multiple wafers, as the scanning distance becomes longer, the interval time for each point on the wafer to contact the beam will also become longer, so there will be more self-repair time and more cooling time, thereby reducing the damage to the lattice and controlling the wafer temperature to a lower level.
[0028] 4. The method of the present invention for simultaneously performing ion implantation process on multiple wafers does not require changing the entire beam system and can be modified on the basis of an existing single chip microcomputer. It is easy to implement and has extremely high application value. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 It is a schematic diagram of the three-dimensional structure of the scanning robot of the first embodiment provided by the present invention when performing ion implantation.
[0030] Figure 2 It is a schematic diagram of the three-dimensional structure of the scanning robot of the second embodiment provided by the present invention when performing ion implantation.
[0031] Figure 3 It is a schematic diagram of the three-dimensional structure of the scanning robot of the third embodiment provided by the present invention when performing ion implantation.
[0032] Figure 4 It is a schematic diagram of the three-dimensional structure of a scanning robot using an existing single-chip microcomputer when performing ion implantation.
[0033] Figure 5 It is a schematic diagram of the existing single-chip scanning injection process and moving distance.
[0034] Figure 6It is a schematic diagram of the process and moving distance of simultaneously implanting two wafers according to the fourth embodiment of the present invention.
[0035] Figure 7 It is a schematic diagram of the overall structure of an ion implantation device provided by the present invention.
[0036] Description of reference numerals in the accompanying drawings:
[0037] 1. Scanning robot; 2. Wafer; 3. Transfer robot; 4. Loading chamber; 5. Ion beam; 6. Vacuum transfer chamber; 7. Process chamber. DETAILED DESCRIPTION
[0038] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0039] It should also be noted that, for ease of description, only the parts related to the invention are shown in the drawings. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.
[0040] It should be noted that the concepts such as "first" and "second" mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.
[0041] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".
[0042] The invention discloses a method for simultaneously performing an ion implantation process on multiple wafers, which belongs to the technical field of semiconductor manufacturing and is particularly suitable for large-beam ion implantation equipment. The ion implantation equipment used in the method is provided with a scanning robot, and more than two target disks are arranged on the scanning robot. The method comprises the following steps: in an initial state, multiple target disks on the scanning robot are all flat and unloaded; then wafers are transferred and placed on the target disks respectively, so that one wafer is placed on each target disk; the scanning robot controls the target disks to hold the wafers, and then turns them over, so that multiple target disks are all erected to the angle required by the process; a scanning process of ion implantation is performed on the wafers, wherein the scanning area of the ion beam can completely cover multiple wafers located on the scanning robot; after completing the ion implantation required by the process, the scanning robot returns to the flat state of the initial state, waiting for the wafers thereon to be removed; and the operation is repeated until the ion implantation of all required wafers is completed. In the existing technical solutions, the single-chip microcomputer process that only scans and implants one wafer at a time has better effect, but there are also some limitations, mainly including: since ion implantation is carried out wafer by wafer, and factors such as the distance and time required for wafer transmission and the time required for ion implantation are difficult to further shorten, it is difficult to further improve the process efficiency; and, especially for large-beam or large-dose ion implantation processes, the temperature of the wafer will rise during repeated scanning and implantation, resulting in greater lattice damage, and after reaching a certain temperature, it is necessary to wait for the wafer to cool down before continuing to scan, which is not conducive to shortening the process time.
[0043] See also Figure 1 The method for simultaneously performing ion implantation on multiple wafers provided by the present invention comprises an ion implantation device having a scanning robot 1, which is used to hold the wafer 2 during the ion implantation process; in some common ion implantation devices at present, the path of the ion beam 5 is fixed during the ion implantation process, and the main part of the scanning robot is a mechanical arm, and the scanning robot controls the wafer to move relative to the ion beam to complete the process of repeated scanning of the ion beam on the wafer. The end of the scanning robot 1 has a target plate, which is a component used to temporarily hold the wafer during the implantation process, and its holding structure and method are, for example, electrostatic adsorption and / or mechanical clamping. In the present invention, more than two target plates are arranged on the scanning robot 1, so that more than two wafers 2 can be held simultaneously for scanning. The target plate is specifically, for example, an electrostatic chuck, and the size of the target plate is generally less than or equal to the size of the wafer. The wafer is placed with the center of the target plate aligned, and there is enough gap between adjacent target plates, so that in the process of placing, holding, and removing two wafers, there is a certain distance between the two wafers, and the process will not be affected by contact.
[0044] The method for simultaneously performing ion implantation on multiple wafers of the present invention mainly comprises the following steps.
[0045] Step S1, the initial state is that the multiple target plates on the scanning robot 1 are all flat and empty; then the wafers 2 are transferred and placed on the target plates respectively, so that each target plate is placed with a wafer 2. Of course, during these processes, the target plates and the wafers 2 are not in contact with the ion beam 5.
[0046] In step S2, the scanning robot 1 controls the target plate to hold the wafer 2, and then flips it so that multiple wafers 2 are erected to the angle required by the process; wherein the generally defined process angle is, for example, the ion beam incident angle, that is, the angle between the ion beam 5 path and the plane where the wafer 2 is located, specifically, for example, 90°, that is, vertical incidence, or set to a certain angle according to the process requirements.
[0047] Step S3, a scanning process for ion implantation is performed on the wafer 2; wherein the scanning area of the ion beam 5 can completely cover the multiple wafers 2 located on the scanning robot 1; the basic method of the scanning process, such as the scanning robot 1 controlling the target plate to translate, can follow the existing technical solution, the main difference being that the path and distance of the mobile scanning are different, the existing single-chip microcomputer only scans one wafer, while the present solution requires scanning multiple wafers.
[0048] Step S4, after completing the ion implantation required for the process (usually after repeated scanning for multiple times, the required implantation dose is reached, and in this solution, the multiple wafers held on the scanning robot 1 have all completed the ion implantation), the scanning robot 1 returns to the initial flat state, waiting for the wafer 2 on it to be removed.
[0049] After the wafer that has been implanted is removed, a new wafer to be processed is placed on top, and steps S1 to S4 are repeated until the ion implantation is completed for all the required number of wafers.
[0050] In a preferred embodiment, three or four target disks are arranged on the scanning robot 1, and the target disks are arranged in a relatively regular and aligned manner or in a staggered arrangement. It is understandable that, to a certain extent, the more wafers are implanted at the same time, the more beneficial the implantation efficiency is, but it should not be too many to avoid excessive impact on wafer transportation and equipment stability. It is better to hold three or four wafers at the same time.
[0051] like Figure 1As shown, in the first embodiment of the present invention, the scanning robot 1 has four target disks, which are distributed in a quadrilateral shape, and two of them are arranged side by side along the scanning direction (in the figure, they are arranged side by side up and down). More specifically, the four target disks are distributed in a rectangular shape, and such regular distribution is a relatively regular arrangement; thus, the wafers 2 are arranged in two regular horizontal rows, with two wafers in each horizontal row, and the two horizontal wafers 2 are adapted to the width of the ion beam 5, for example, the diameter of the wafer 2 is 150 mm, and the width of the ion beam 5 is about 300 mm (generally slightly larger than 300 mm).
[0052] like Figure 2 As shown, in the second embodiment of the present invention, the scanning robot 1 has three target disks, and the three target disks are distributed in a triangular shape. More specifically, the three target disks are distributed in an isosceles triangle or an equilateral triangle, and two of them are arranged side by side along the scanning direction (arranged side by side up and down in the figure), and the other is located next to the two and corresponds to the position between the two; this type of distribution is a staggered arrangement. Compared with the first embodiment, the arrangement of this embodiment makes the total width of multiple wafers smaller, which is more conducive to making the ion beam 5 completely cover the wafer size.
[0053] It is conceivable that the target plates may be arranged in other ways, such as a relatively aligned regular arrangement or a combination of staggered arrangements; for example, as a variation of the first embodiment, the four target plates are in a non-rectangular parallelogram, that is, two vertical rows of staggered arrangements.
[0054] like Figure 3 As shown, in the third embodiment of the present invention, the scanning robot 1 has two target plates, which are arranged side by side along the scanning direction (in the figure, they are arranged side by side up and down). Figure 4 As shown, it is an existing single wafer implantation method, where there is only one target plate on the scanning robot 1 and only one wafer is held for scanning.
[0055] As a preferred application mode of the present invention, the ion beam 5 is a ribbon beam, and the length of the cross-sectional shape of the ion beam 5 is not less than twice the diameter of the wafer 2. For example, the ion beam is about 300 mm wide (ion beams of this size are more commonly used), and ion implantation is performed on 150 mm wafers. Each scanning implantation can be performed on up to four wafers at the same time. Overall, the average implantation time of each wafer can be significantly shortened.
[0056] More specifically, the ion beam 5 used for ion implantation in the ion implantation device is a flat ribbon beam with a transverse cross-section; transverse means that the horizontal length is much longer than the vertical length, and the flat shape can be a rectangle, a rounded rectangle, or an ellipse, etc. The ion beam 5 forms a ribbon along its transmission path, so it is called a ribbon beam.
[0057] In the initial state described in step S1 , the ion beam 5 passes over the target disk; there is a certain distance between the ion beam 5 and the target disk and the rest of the scanning robot 1 .
[0058] After flipping in step S2, the plane where the multiple wafers 2 are located is in an upright state or at a certain angle to the vertical plane, and at this time all the wafers 2 are still located below the ion beam 5, and can be selected to be close to the ion beam 5 but not yet in contact with the ion beam 5. The above position and distance relationship can be achieved by setting the position of the flip axis and the initial state of the scanning robot 1.
[0059] When ion implantation is performed in step S3, during the scanning process, each scan causes the ion beam to completely scan the two wafers; more specifically, the scanning robot 1 first controls the two target disks to move upward or obliquely upward (for example, the target disks translate within their planes, or translate in other directions perpendicular to the ion beam 5, and the ion beam incident angle remains unchanged or substantially unchanged during the movement), so that one or several wafers above first contact the ion beam 5, and then the ion beam 5 continues to scan, and finally the ion beam 5 completely scans all wafers 2 and moves an over scan distance, thus completing one scan; the next scan is the process in which the scanning robot 1 controls the target disk to move downward or obliquely downward, and after the scan, all wafers 2 are located below the ion beam 5; and the up and down scanning is repeated.
[0060] Please also see Figure 7 The ion implantation equipment used has a loading chamber 4 (Loadlock) and a transfer robot 3, and there are two transfer robots 3, for example. The transfer robot 3 is used to transfer wafers between the loading chamber 4 and the target disk, and one or more transfer robots 3 can realize the wafer placement at the target disk without affecting other target disks and wafers on the target disk. Taking the case of the four target disks shown in the figure as an example, it is optional to equip two transfer robots 3 that can rotate and retract (this type of structure is existing), so that the two target disks on the left side of the figure can be taken and placed from the upper and lower sides of the figure respectively, without affecting or crossing the two target disks on the right side of the figure. Generally, wafers are exchanged (taken and placed) one by one on the target disk; for the illustrated embodiment, or other structures, there are target disks that can be exchanged at the same time (for example, the two target disks on the right side of the figure), then it can also be selected to select simultaneous exchange for these target disks to further shorten the process time.
[0061] In a preferred embodiment, each transfer robot 3 has two mechanical arms; after step S4 and in step S1, in the process of removing the wafer from the scanning robot 1 and placing the wafer on the two target disks, one of the mechanical arms of a transfer robot 3 is used to remove the wafer from the target disk, and the other mechanical arm is used to place the new wafer to be processed on the target disk; in this way, there will be two wafers on the mechanical arms at the same time, which helps to improve the wafer transmission efficiency. More specifically, for example, the two mechanical arms of each transfer robot 3 are an upper arm and a lower arm, and the ends of the upper arm and the lower arm have claws for carrying wafers, and the claws of the upper arm are located above the claws of the lower arm; the lower arm is used to remove the wafer from the target disk, and the upper arm is used to place the new wafer to be processed on the target disk. While the injection is in progress, the new wafer to be processed will be transferred to the upper arm of the transfer robot. After the injection is completed, the lower arm of the transfer robot will take the wafer on the target plate, and then the upper arm will place the wafer on the target plate. After the scanning robot is fully loaded, ion injection will be carried out, and so on, until the process of the entire box of wafers is completed.
[0062] See also Figure 5 , Figure 6 , a comparison is made by taking an existing process and the fourth embodiment of the present invention in which two wafers are implanted simultaneously as examples. In the fourth embodiment, two wafers are implanted simultaneously, and the scanning process consists of multiple reciprocating scans, wherein the total moving distance of each scan is not less than the sum of the diameters of the two wafers, the spacing between the two wafers, and an overscan distance; wherein the overscan distance is greater than the height of the ion beam. Taking the case where the diameter of the wafer is 300mm, the spacing between the two wafers is 10mm, and the overscan distance is 100mm as an example, the total moving distance of one scan is 300+300+10+100=710mm. In the case of the same wafer size and overscan distance, please refer to Figure 5, when the existing single-chip microcomputer is used for scanning, the total moving distance of one scan is 300+100=400mm. In the process of ion implantation, although the scanning distance of this scheme is farther than that of the single-chip microcomputer, both the single-chip microcomputer and this scheme must be over-scanned to ensure the integrity of the whole wafer implantation; then for this scheme, the over-scanning distance is the same under the same conditions, and the advantage is that the over-scanning distance of each wafer in the double-wafer implantation is equivalent to half of the over-scanning distance in the single-wafer implantation. That is, after adopting the double-wafer simultaneous implantation scheme, the average scanning distance of each wafer is 710 / 2=355mm, which is 355 / 400=88.7% compared with the existing process scheme, thereby reducing the time required for ion implantation. It can be understood that the scheme of three or four wafers and other multiple wafers implanted simultaneously has different specific size values, but also has similar advantages as mentioned above, especially for the case of four 150mm wafers implanted simultaneously, the average scanning distance of each wafer will be more significant compared with the existing process.
[0063] Also, for the solution of simultaneously injecting multiple wafers and cutting two or more wafers at the same time, since there is a synchronous process of taking and placing the wafers, it can save time and comprehensively improve WPH compared with single-wafer transmission, and this solution will not affect the process results and the safe and reliable operation of the equipment.
[0064] In addition, during the implantation process, because the scanning distance becomes longer, the interval time for each point on the wafer to contact the beam will become longer, which will result in: 1. more self-repair time; 2. more cooling time. In this way, the lattice damage will be lower and the wafer temperature will be controlled lower, which is beneficial to the process and the final product quality.
[0065] Furthermore, a baffle is contained in the loading chamber 4; the baffle is, for example, a sheet of the same size as the wafer, and the material is, for example, silicon or graphite or the same or similar to the wafer, so that it can contact the ion beam without causing contamination. In the case where ion implantation is required for wafers less than the number of target disks, in step S1, the baffle is used as a substitute for the wafer 2 and is transferred and placed on the target disk, so that each target disk is placed with a wafer 2 or a baffle to prevent the ion beam from directly irradiating the target disk. After the implantation is completed, the baffle will be returned to the loading chamber to wait for the next application.
[0066] In the fifth embodiment of the present invention, please refer to Figure 7(For the sake of simplifying the basic structural diagram, the specific details are not presented, and can be adjusted in actual application), the ion implantation equipment used therein has a loading chamber 4, a vacuum transmission chamber 6 and a process chamber 7 connected in sequence, the transmission robot 3 is located in the vacuum transmission chamber 6, and the scanning robot 1 is located in the process chamber 7; and at least the loading chamber 4 and the vacuum transmission chamber 6 are sealed and opened and closed, for example, there is a gate valve between them. In this way, the whole process of ion implantation is completed under high vacuum and high cleanliness. Preferably, the positions of the scanning robot 1, the transmission robot 3, and the loading chamber 4 form an axisymmetric relationship, and the paths of the two transmission robots 3 transmitting wafers are symmetrical and do not intersect at least in the vacuum transmission chamber 6 and the process chamber 7 (optionally, the wafers are taken from the same loading chamber 4 in sequence), so as to realize a flexible and efficient process of transmitting wafers. In this embodiment, there are specifically two loading chambers 4, which correspond to the two transmission robots 3 respectively, and the paths of the two transmission robots 3 transmitting wafers are completely non-intersecting, so that the two transmission robots 3 can work simultaneously without affecting each other. In addition, the vacuum transfer chamber 6 or a separate chamber (not shown in the figure) connected to the vacuum transfer chamber 6 also has a wafer alignment mechanism, a heating mechanism and / or a cooling mechanism, etc. to meet the corresponding functional requirements; the wafer alignment mechanism, heating mechanism and / or cooling mechanism, etc. can also be selected as one / a group shared by the two transfer robots 3, or two / two groups corresponding to the two transfer robots 3 respectively.
[0067] Please also see Figure 1 A specific scanning robot 1 includes a scanning mechanical arm, one end of which is connected to the inner wall of the process chamber of the ion implantation device, and the other end of the scanning mechanical arm is a target plate base, on which the target plate is arranged. The target plate base can be flipped under control, and can be translated with the scanning mechanical arm without changing the wafer angle. The middle of the target plate base corresponds to the middle of the multiple target plates, in other words, corresponds to the geometric center of the overall shape formed by the multiple target plates. The position of the target plate makes it relatively balanced on the target plate base, so it can be relatively stable during the flipping and translation scanning action of the scanning robot 1.
[0068] When the ion implantation process is performed in this embodiment, the basic principle process is similar to the above scheme. Specifically, during the operation of the transfer robot 3 in step S1 and step S4, it can be selected that, unlike the above embodiment, the lower arm is used to obtain a new wafer from the loading chamber 4, and after the transfer robot 3 rotates to face the target plate 2, the unloaded upper arm extends, removes the processed wafer from the target plate 2, and then rises to a certain extent before or during the process of leaving the target plate 2, thereby forming a space for the lower arm to extend and place the new wafer more quickly, thus completing the wafer exchange process; wherein, the structure of the transfer robot in which the upper and lower arms can be independently extended and lifted is achievable based on the prior art and will not be described in detail here. In step S3, the number of scans is set to an even number, so that in step S4, after the ion implantation required for the process is completed, the scanning robot 1 is in the initial state or close to the initial state. The remaining steps and processes can be selected to be the same or similar to the above embodiment.
[0069] It is understandable that in some feasible embodiments, the process of placing wafers on the target plate is not carried out synchronously, but is placed one by one or successively with a time difference by one or more existing transfer robots. Compared with the aforementioned preferred embodiment with a simultaneous exchange process, its efficiency is lower, but still higher than the existing single-chip microcomputer solution.
[0070] In some other embodiments, there is one or two loading chambers 4. During operation, two transfer robots 3 take / place wafers in the same loading chamber 4 in turn, and the other loading chamber 4 is in the process of loading / unloading / vacuuming / releasing the vacuum. The two loading chambers 4 work alternately, thereby improving the overall efficiency.
[0071] In some other embodiments, the scanning process of performing ion implantation on the wafer in step S3 is designed to be more flexible, for example, Figure 1 , Figure 3 In the embodiment shown, the upper wafer may be scanned several times first, and then the lower wafer may be scanned, while the upper wafer is being cooled, and the two wafers may be scanned alternately; for a single wafer with a baffle, the upper target plate may be used to hold the wafer and the lower target plate may be used to hold the baffle, and when working, similar to the existing single-chip microcomputer, only the wafer is scanned, and the baffle is only used to prevent the ion beam from directly irradiating the target plate and other structures. The position of the baffle in the loading chamber 4 is, for example, the top or bottom, so that after processing the wafers one by one, the last wafer will be close to the baffle position, which is convenient for quick picking.
[0072] In summary, the method for simultaneously performing ion implantation on multiple wafers of the present invention has multiple target plates on the scanning robot, so that multiple wafers can be held simultaneously for scanning implantation; the scanning process of ion implantation requires a certain amount of overscanning to ensure the integrity of the entire implantation, and for the scheme of simultaneously scanning multiple wafers, only one overscanning distance is required, so the average processing time of each wafer can be effectively shortened; for example, the ion beam has a width of about 300 mm, and when processing a 150 mm wafer, at most four wafers can be placed and implanted simultaneously, thereby greatly improving the production capacity; the method for simultaneously performing ion implantation on multiple wafers of the present invention is similar to the existing Compared with existing process methods, the WPH (wafer output per hour) can be comprehensively improved without affecting the process results and the safe and reliable operation of the equipment; in the method of simultaneously performing ion implantation process on multiple wafers of the present invention, since the scanning distance becomes longer, the interval time for each point on the wafer to contact the beam will also become longer, so there will be more self-repair time and more cooling time, and then the lattice damage will be lower, and the wafer temperature will be controlled to be lower; the method of simultaneously performing ion implantation process on multiple wafers of the present invention does not need to change the entire beam system, can be modified on the basis of the existing single-chip microcomputer, is easy to implement, and has extremely high application value.
[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for simultaneously performing an ion implantation process on multiple wafers, wherein the ion implantation equipment used has a scanning robot (1), characterized in that: Two or more target plates are arranged on the scanning robot (1); The method for simultaneously performing ion implantation on multiple wafers comprises the following steps: Step S1, in an initial state, multiple target plates on the scanning robot (1) are all placed flat and empty; then the wafers (2) are transferred and placed on the target plates respectively, so that a wafer (2) is placed on each target plate; Step S2, the scanning robot (1) controls the target plate to hold the wafer (2), and then flips the target plate so that the plurality of wafers (2) are all erected to an angle required by the process; Step S3, performing a scanning process of ion implantation on the wafer (2); wherein the scanning area of the ion beam (5) can completely cover the plurality of wafers (2) located on the scanning robot (1); Step S4, after completing the ion implantation required for the process, the scanning robot (1) returns to the initial flat state, waiting for the wafer (2) thereon to be removed; Steps S1 to S4 are repeated until the ion implantation is completed for all the required number of wafers.
2. The method for simultaneously performing ion implantation on multiple wafers according to claim 1, characterized in that: Three or four target plates are arranged on the scanning robot (1), and the target plates are arranged in a relatively aligned regular arrangement or in a staggered arrangement.
3. The method for simultaneously performing ion implantation on multiple wafers according to claim 1, characterized in that: The scanning robot (1) is provided with four target plates, which are distributed in a quadrilateral shape, and two of the target plates are arranged side by side along the scanning direction.
4. The method for simultaneously performing ion implantation on multiple wafers according to claim 3, characterized in that: The four target discs are arranged in a rectangular shape.
5. The method for simultaneously performing ion implantation on multiple wafers according to claim 1, characterized in that: The scanning robot (1) is provided with three target plates, which are distributed in a triangle.
6. The method for simultaneously performing ion implantation on multiple wafers according to claim 5, characterized in that: The three target plates are distributed in the shape of an isosceles triangle or an equilateral triangle, and two of them are arranged side by side along the scanning direction.
7. The method for simultaneously performing ion implantation on multiple wafers according to any one of claims 1 to 6, characterized in that: The ion beam (5) is a ribbon beam, and the length of the cross-sectional shape of the ion beam (5) is not less than twice the diameter of the wafer (2).
8. The method for simultaneously performing ion implantation on multiple wafers according to any one of claims 1 to 6, characterized in that: The ion implantation device used therein comprises a loading chamber (4) and a transfer robot (3), wherein the transfer robot (3) is used to transfer wafers between the loading chamber (4) and a target disk; one or more baffles are contained in the loading chamber (4); In the case where ion implantation is required for wafers less than the number of target disks, in step S1, a baffle is used as a substitute for the wafer (2) and is transferred and placed on the target disk, so that each target disk is placed with a wafer (2) or a baffle.
9. The method for simultaneously performing ion implantation on multiple wafers according to any one of claims 1 to 6, characterized in that: In step S3, during the scanning process, each scan causes the ion beam (5) to completely scan all wafers (2).
10. The method for simultaneously performing ion implantation on multiple wafers according to any one of claims 1 to 6, characterized in that: The ion beam (5) used for ion implantation in the ion implantation device is a ribbon-shaped beam with a flat cross section; In the initial state described in step S1, the ion beam (5) passes over the target disk; After flipping in step S2, all wafers (2) are located below the ion beam (5); When ion implantation is performed in step S3, the scanning robot (1) controls the target plate to move upward or diagonally upward, so that the ion beam (5) completely scans all wafers (2) and moves a certain overscan distance, thus completing one scan; the next scan is a process in which the scanning robot (1) controls the target plate to move downward or diagonally downward, and after the scan, all wafers (2) are located below the ion beam (5); and the up and down scans are repeated in this way.