Method for performing ion implantation process through double target disks

Abstract

The invention discloses a method for carrying out an ion implantation process through double target discs, and belongs to the technical field of semiconductor manufacturing, the tail end of a scanning robot is provided with two target discs which are arranged side by side in the scanning direction, and the method comprises the following steps: in an initial state, the two target discs on the scanning robot are both flatly placed and no-load; then the two wafers are transmitted and placed on the two target discs respectively; the scanning robot controls the target discs to fixedly hold the wafer, and then the target discs are overturned, so that the two target discs are erected to the angle required by the process; performing a scanning process of ion implantation on the two wafers on the two target discs; and after ion implantation required by the process is completed, the scanning robot returns to the flatwise state of the initial state, and waits for the wafer on the scanning robot to be taken down. According to the method, the whole injection time is saved, the WPH can be comprehensively improved by about 20%, the damage to crystal lattices is lower, and the wafer temperature is controlled to be lower; the whole beam system does not need to be changed, the process is stable, implementation is easy, and the method has extremely high application value.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor manufacturing, and in particular relates to a method for performing an ion implantation process through a double target disk. Background Art

[0002] As ion implantation is increasingly used, it plays a significant role not only in memory devices, but also in power devices and SOI silicon wafer manufacturing. As the beam power (energy multiplied by beam size) requirements become higher and higher or the dose becomes larger (the dose in SOI reaches E16), temperature control and yield improvement are very big challenges for ion implantation. Since the manufacture of 12-inch wafers, single-chip microcomputers (i.e., devices that only implant one wafer per ion implantation process and implant one wafer at a time) have been more popular because single-chip microcomputers have better transmission stability, lower suspended particles, better uniformity and angle distribution than disk implantation (an earlier type of equipment, with a basic structure of distributing multiple wafers on a large disk. After one ion implantation is completed, all wafers on the large disk are implanted). However, if you want to increase the yield or improve the temperature, the single-chip microcomputer will also be subject to certain limitations, so 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 performing ion implantation process through dual target plates, which solves the problem that the prior art process is difficult to further improve the yield or improve the temperature. By adopting the method of simultaneously injecting and exchanging two wafers, the comprehensive improvement of the process WPH (wafer yield per hour) is achieved, while ensuring the process quality and operation reliability.

[0004] According to the technical solution of the present invention, the present invention provides a method for performing an ion implantation process through a dual target disk, wherein the ion implantation device used has a scanning robot, and the scanning robot has two target disks arranged side by side along a scanning direction; the method for performing an ion implantation process through a dual target disk comprises the following steps:

[0005] Step S1, the initial state is that the two target plates on the scanning robot are both flat and empty; then two wafers are transferred and placed on the two target plates respectively;

[0006] Step S2, the scanning robot controls the target plate to hold the wafer, and then flips the target plate so that both target plates are erected to the angle required by the process;

[0007] Step S3, performing a scanning process of ion implantation on two wafers on two target plates;

[0008] 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;

[0009] Steps S1 to S4 are repeated in this way until the ion implantation of all required wafers is completed.

[0010] Furthermore, the ion implantation device used therein has a loading chamber and two transfer robots, and the transfer robots are used to transfer wafers between the loading chamber and the target disk; in step S1, the process of two wafers being transferred and placed on two target disks respectively is completed simultaneously by the two transfer robots.

[0011] Furthermore, each transfer robot has two robotic arms; after step S4 and in step S1, in the process of removing the wafer from the scanning robot and placing the wafer on the two target plates, each transfer robot corresponds to a target plate, one of the robotic arms of the transfer robot is used to remove the wafer from the target plate, and the other robotic arm is used to place the new wafer to be processed on the target plate.

[0012] Furthermore, each transfer robot has two mechanical arms, namely an upper arm and a lower arm, and the ends of the upper arm and the lower arm are provided with 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 wafers from the target plate, and the upper arm is used to place new wafers to be processed on the target plate.

[0013] Furthermore, a baffle is contained in the loading chamber; in the case where only one wafer needs to be ion implanted, in step S1 , the baffle is used as a substitute for a wafer to be transferred and placed on the target disk.

[0014] Furthermore, in step S3, during the scanning process, each scan causes the ion beam to completely scan across the two wafers.

[0015] Further, in step S3, the scanning process is composed 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.

[0016] Furthermore, the scanning robot includes a scanning mechanical arm, one end of which is connected to the ion implantation device, and the other end of which is a target plate base. The target plate is arranged on the target plate base, and the middle of the target plate base corresponds to the middle of the two target plates.

[0017] Furthermore, the ion beam used for ion implantation in the ion implantation device is a ribbon-shaped beam with a flat cross-section;

[0018] In the initial state described in step S1, the ion beam passes over the target disk;

[0019] After flipping in step S2, the two target disks are arranged one above the other, and both wafers are located below the ion beam;

[0020] When ion implantation is performed in step S3, the scanning robot first controls the two target plates to move upward or diagonally upward so that the upper wafer contacts the ion beam first, and then the ion beam completely scans the upper wafer, then the ion beam passes through the gap between the two wafers and contacts the lower wafer, and finally the ion beam completely scans the lower wafer and moves a certain overscan distance, thus completing one scan; the next scan is the process in which the scanning robot controls the two target plates to move downward or diagonally downward, and after the scan, both wafers are located below the ion beam; and the up and down scans are repeated in this way.

[0021] Furthermore, the ion implantation equipment used therein comprises a loading chamber, a vacuum transmission chamber and a process chamber which are connected in sequence, the transmission robot is located in the vacuum transmission chamber, and the scanning robot is located in the process chamber.

[0022] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0023] 1. The method of performing ion implantation process through dual target plates of the present invention performs ion implantation process through two target plates. The dual target plates are preferably synchronous when taking and placing wafers, and the time used for transmission is substantially the same as the time taken by the single chip microcomputer to transmit one wafer. The scanning process of ion implantation requires a certain amount of overscanning to ensure the integrity of the whole wafer implantation. Therefore, although the dual target plate scheme needs to scan two wafers and the distance is longer than that of the single chip microcomputer, it only requires a certain overscanning distance. Therefore, the overscanning distance of each wafer in the dual wafer implantation is equivalent to half of the overscanning distance in the single wafer implantation, thereby saving the entire implantation time.

[0024] 2. Compared with the existing process methods, the method of ion implantation through dual target plates of the present invention can reduce the average implantation time of each wafer by 12% without affecting the process results and the safe and reliable operation of the equipment, and comprehensively improve the WPH (wafer output per hour) by about 20%.

[0025] 3. In the method of the present invention for performing ion implantation process through double target plates, 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.

[0026] 4. The method of the present invention for performing ion implantation process through dual target plates 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

[0027] Figure 1 It is a schematic diagram of the three-dimensional structure of the scanning robot with double target plates provided by the present invention when performing ion implantation.

[0028] Figure 2 It is a schematic diagram of the three-dimensional structure of the scanning robot with dual target plates provided by the present invention when performing wafer exchange.

[0029] Figure 3 It is a schematic diagram of the scanning process and moving distance using the existing single target disk method.

[0030] Figure 4 It is a schematic diagram of the scanning process and moving distance using the dual target disk method of the present invention.

[0031] Figure 5 It is a schematic diagram of the overall structure of an ion implantation device provided by the present invention.

[0032] Description of reference numerals in the accompanying drawings:

[0033] 1. Scanning robot; 2. Target plate; 3. Transfer robot; 4. Loading chamber; 5. Ion beam; 6. Vacuum transfer chamber; 7. Process chamber. DETAILED DESCRIPTION

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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".

[0038] The invention discloses a method for performing an ion implantation process through a double target disk, which belongs to the technical field of semiconductor manufacturing and is particularly suitable for a large beam current ion implantation device. The ion implantation device used in the invention comprises a scanning robot, and the scanning robot comprises two target disks arranged side by side along a scanning direction. The method comprises: in an initial state, the two target disks on the scanning robot are both flat and unloaded; then two wafers are transferred and respectively placed on the two target disks; the scanning robot controls the target disks to hold the wafers, and then flips the target disks so that the two target disks are erected to the angles required by the process; a scanning process of ion implantation is performed on the two wafers on the two target disks; after completing the ion implantation required by the process, the scanning robot returns to the initial state and waits for the wafers thereon to be removed. 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 transfer 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 cabinet time.

[0039] See also Figure 1 The method for performing ion implantation process by double target plates provided by the present invention has a scanning robot 1 in the ion implantation equipment used, and the scanning robot 1 is used to hold the wafer during the ion implantation process; in some common ion implantation equipment currently, 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, the end of the scanning robot 1 has two target plates 2 arranged side by side along the scanning direction, so that two wafers can be held simultaneously for scanning; of course, there is a sufficient gap between the two target plates 2, so that in the process of placing, holding, and removing the two wafers, there is a certain distance between the two wafers and they will not contact each other.

[0040] The method for performing ion implantation process through double target plates of the present invention mainly comprises the following steps.

[0041] Step S1, the initial state is that the two target plates 2 on the scanning robot 1 are both flat and empty. Then two wafers are transferred and placed on the two target plates 2 respectively. Of course, during these processes, the target plates 2 and the wafers are not in contact with the ion beam 5.

[0042] In step S2, the scanning robot 1 controls the target plate 2 to hold the wafer, and then flips it so that both target plates 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 is located, specifically, for example, 90°, that is, vertical incidence, or set to a certain angle according to the process requirements.

[0043] Step S3, a scanning process of ion implantation is performed on the two wafers on the two target plates 2; the basic method of the scanning process, such as the scanning robot 1 controlling the target plate 2 to translate, can follow the existing technical solution, the main difference being the different paths and distances of the mobile scanning, the existing single-chip microcomputer only scans one wafer, and this solution requires scanning two wafers.

[0044] 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, both wafers have completed the ion implantation), the scanning robot 1 returns to the initial flat state, waiting for the wafer on it to be removed.

[0045] 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 of all required wafers is completed.

[0046] More specifically, in the first embodiment of the present invention, 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 length in the horizontal direction is much larger than the length in the vertical direction, 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.

[0047] In the initial state described in step S1 , the ion beam 5 passes over the target disk 2 ; there is a certain distance between the ion beam 5 and the target disk 2 and the rest of the scanning robot 1 .

[0048] After flipping in step S2, the two target plates 2 are arranged one above the other, and at this time, the two wafers 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.

[0049] When ion implantation is performed in step S3, the scanning robot 1 first controls the two target plates 2 to move upward or obliquely upward (for example, the target plates 2 translate within the plane in which they are located, or translate in other directions perpendicular to the ion beam 5, and the incident angle of the ion beam remains unchanged or substantially unchanged during the movement), so that the upper wafer first contacts the ion beam 5, and then the ion beam 5 completely scans the upper wafer, then the ion beam 5 passes through the gap between the two wafers and contacts the lower wafer, and finally the ion beam 5 completely scans the lower wafer and moves an over scan distance, thus completing one scan; the next scan is the process in which the scanning robot 1 controls the two target plates 2 to move downward or obliquely downward, and after the scan, both wafers are located below the ion beam 5; and the up and down scans are repeated in this way.

[0050] Please also see Figure 2 The ion implantation equipment used has a loading chamber 4 (Loadlock) and two transfer robots 3, and the transfer robots 3 are used to transfer wafers between the loading chamber 4 and the target disk 2; there are at least two transfer robots 3. Furthermore, in step S1, the process of transferring two wafers and placing them on two target disks 2 is completed by two transfer robots 3 at the same time. Further preferably, the work of transferring wafers between the loading chamber 4 and the target disk 2 is completed by only two transfer robots 3 (the number is as small as possible, saving transmission time and equipment space), and 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 2, each transfer robot 3 corresponds to a target disk 2, one of the mechanical arms of the transfer robot 3 is used to remove the wafer from the target disk 2, and the other mechanical arm is used to place the new wafer to be processed on the target disk 2. In this way, there will be two wafers on the mechanical arm at the same time.

[0051] More specifically, 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 are provided with 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 take off the wafers on the target plate 2, and the upper arm is used to place the new wafers to be processed on the target plate 2. The mechanical arms will simultaneously transfer the wafers from the vacuum transfer chamber to the double target plates in the process chamber (PTM), and then perform the injection. During the injection, the other two wafers will be transferred to the two upper arms of the two transfer robots. After the injection is completed, the two lower arms of the two transfer robots will take the wafers on the target plates, and then the two upper arms will transfer the wafers to the double target plates, and then continue the double wafer injection, and the next two wafers will be transferred to the two upper arms again... and so on, until the whole box of wafers is processed.

[0052] Taking an existing process as an example for comparison, the average WPH according to POR is 75 pieces / hour, of which the exchange and process time of each piece is 48 seconds; after changing to the simultaneous injection of two pieces and the simultaneous exchange of two pieces of this solution, the comprehensive improvement of WPH result is: 20%, and this solution will not affect the process results and the safe and reliable operation of the equipment.

[0053] In this solution, the dual target plates are synchronized when placing and taking wafers, so the time used for transmission is the same as the time it takes for the single chip microcomputer to transmit one wafer. By adopting this simultaneous exchange method of the present invention, the exchange time for each wafer can be reduced by 4 seconds, that is, the time is reduced by 4 / 48=8.3%.

[0054] In addition, since two wafers are implanted simultaneously, the process time per wafer can be reduced by 12%. Figure 4 , in step S3, during the scanning process, each scan makes the ion beam completely scan the two wafers. More specifically, in step S3, the scanning process is composed 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. In the first embodiment of the present invention, 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 300mm+300mm+10mm+100mm=710mm. In the case of the same wafer size and overscan distance, please refer to Figure 3 , when the existing single-chip microcomputer is used for scanning, the total moving distance of one scan is 300mm+100mm=400mm. In the process of ion implantation, although the scanning distance of the dual-target disk scheme of the present invention is farther than that of the single-chip microcomputer, both the single-chip microcomputer and the dual-target disk must be over-scanned to ensure the integrity of the entire implantation during the ion implantation process; then for the dual-target disk, under the same over-scanning distance, the advantage of the dual-chip distance is that the over-scanning distance of each wafer in the dual-chip implantation is equivalent to half of the over-scanning distance in the single-chip implantation. That is, after adopting the dual-target disk 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.

[0055] In addition, during the implantation process, the scanning distance of the double target disk becomes longer, so 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 at a lower level, which is beneficial to the process and the final product quality.

[0056] 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 only one wafer needs to be ion implanted, in step S1, the baffle is used as a substitute for a wafer and is transferred and placed on the target disk 2 to prevent the ion beam from directly irradiating the target disk 2 and other parts that are not suitable for contacting the ion beam; more specifically, the baffle is placed on the target disk below. After the implantation is completed, the baffle will be returned to the loading chamber and wait for the next application.

[0057] In the second embodiment of the present invention, please refer to Figure 5 (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.

[0058] Please also see Figure 1 , Figure 2 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 equipment, and the other end of the scanning mechanical arm is a target plate base, on which the target plate 2 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 two target plates 2. In other words, the two target plates 2 are arranged symmetrically and balanced, so the scanning robot 1 can be relatively stable during the flipping and translation scanning action.

[0059] 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.

[0060] It is understandable that in other feasible embodiments, the process of placing wafers on the dual target plates 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 above-mentioned preferred embodiments of the present invention, its efficiency is lower, but still higher than the existing single-chip microcomputer solution.

[0061] In some other embodiments, there are one or two loading chambers 4, and when working, two transfer robots 3 sequentially take / place wafers in the same loading chamber 4, and the other loading chamber 4 is in the process of loading / unloading / vacuuming / releasing vacuum, and the two loading chambers 4 work alternately, which helps the overall efficiency; and the paths of the two transfer robots 3 can be selected to be different, and the transfer path of the transfer robot 3 that takes / places the wafer first is relatively longer, so that when taking / placing wafers in sequence from the same loading chamber 4, the process of taking / placing wafers on the double target plates of the scanning robot 1 can still be achieved at the same time. In some other embodiments, the transfer robots 3 are more (for example, four) conventional single-arm transfer robots, and the sequential or synchronous wafer exchange process is achieved through coordinated work.

[0062] In some other embodiments, the scanning process of ion implantation of two wafers in step S3 is designed to be more flexible. For example, the upper wafer may be scanned several times first, and then the lower wafer may be scanned, while the upper wafer is cooled, and the two wafers are scanned alternately. For the implantation of 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. 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.

[0063] In summary, the method of performing ion implantation through dual target disks of the present invention performs ion implantation through two target disks, and the dual target disks are preferably synchronized when placing and picking up wafers, and the time used for transmission is substantially the same as the time for the single chip microcomputer to transmit one wafer; the scanning process of ion implantation requires a certain amount of overscanning to ensure the integrity of the whole wafer implantation, so although the dual target disk solution needs to scan two wafers and the distance is longer than that of the single chip microcomputer, it only needs a section of overscanning distance, so the overscanning distance of each wafer in the dual wafer implantation is equivalent to half of the overscanning distance in the single wafer implantation, thus saving the entire implantation time. Compared with the existing process method, the method of performing ion implantation through dual target disks of the present invention can reduce the average implantation time of each wafer by 12% without affecting the process results and the safe and reliable operation of the equipment, and comprehensively improve the WPH (wafer output per hour) by about 20%. In the method of performing ion implantation through dual target disks of the present invention, due to the longer scanning distance, the interval time of each point on the wafer contacting the beam will also be longer, so there will be more self-repair time and more cooling time, and thus the lattice damage will be lower and the wafer temperature will be controlled lower. The method of the present invention for performing ion implantation through double target plates does not require changing the entire beam system, can be modified on the basis of an existing single chip microcomputer, is easy to implement, and has extremely high application value.

[0064] 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 performing an ion implantation process using a double target plate, wherein the ion implantation device used has a scanning robot (1), characterized in that: The scanning robot (1) is provided with two target plates (2) arranged side by side along a scanning direction; The method for performing ion implantation using a dual target plate comprises the following steps: Step S1, the initial state is that the two target plates (2) on the scanning robot (1) are both flat and empty; then two wafers are transferred and placed on the two target plates (2) respectively; Step S2, the scanning robot (1) controls the target plate (2) to hold the wafer, and then flips the target plate (2) so that both target plates (2) are erected to the angle required by the process; Step S3, performing a scanning process of ion implantation on two wafers on two target plates (2); 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 on it to be removed; Steps S1 to S4 are repeated in this way until the ion implantation of all required wafers is completed.

2. The method for performing ion implantation using a dual target plate according to claim 1, characterized in that: The ion implantation device used therein comprises a loading chamber (4) and two transfer robots (3), wherein the transfer robots (3) are used to transfer wafers between the loading chamber (4) and the target plate (2); In step S1, the process of two wafers being transferred and placed on two target plates (2) respectively is completed simultaneously by two transfer robots (3).

3. The method for performing ion implantation using a dual target plate according to claim 2, characterized in that: 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 plates (2), each transfer robot (3) corresponds to a target plate (2), one of the mechanical arms of the transfer robot (3) is used to remove the wafer from the target plate (2), and the other mechanical arm is used to place a new wafer to be processed on the target plate (2).

4. The method for performing ion implantation using a dual target disk according to claim 3, characterized in that: Each transfer robot (3) has two mechanical arms, an upper arm and a lower arm, each of which has a claw for carrying wafers at the end, and the claw of the upper arm is located above the claw of the lower arm; The lower arm is used to remove the wafer from the target plate (2), and the upper arm is used to place a new wafer to be processed on the target plate (2).

5. The method for performing ion implantation using a dual target plate according to claim 1, characterized in that: A baffle is accommodated in the loading cavity (4); In the case where only one wafer needs to be implanted with ions, in step S1, a baffle is used as a substitute for a wafer and is transferred and placed on the target plate (2).

6. The method for performing ion implantation using a dual target plate according to claim 1, wherein: In step S3 , during the scanning process, each scan causes the ion beam to completely scan across the two wafers.

7. The method for performing ion implantation using a dual target plate according to claim 6, characterized in that: In step S3, the scanning process is composed 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 distance between the two wafers, and an overscan distance.

8. The method for performing ion implantation using a dual target plate according to any one of claims 1 to 7, characterized in that: The scanning robot (1) comprises a scanning mechanical arm, one end of which is connected to an ion implantation device, and the other end of which is a target plate base. The target plate (2) is arranged on the target plate base, and the middle of the target plate base corresponds to the middle of the two target plates (2).

9. The method for performing ion implantation using a dual target plate according to claim 8, 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 plate (2); After turning over in step S2, the two target plates (2) are arranged one above the other, and the two wafers are both located below the ion beam (5); When ion implantation is performed in step S3, the scanning robot (1) first controls the two target plates (2) to move upward or obliquely upward, so that the upper wafer first contacts the ion beam (5), then the ion beam (5) completely scans the upper wafer, then the ion beam (5) passes through the gap between the two wafers and contacts the lower wafer, and finally the ion beam (5) completely scans the lower wafer and moves a certain overscan distance, thus completing one scan; the next scan is the process in which the scanning robot (1) controls the two target plates (2) to move downward or obliquely downward, and after the scan, the two wafers are both located below the ion beam (5); and the up and down scans are repeated in this way.

10. The method for performing ion implantation using a dual target plate according to any one of claims 2 to 4, characterized in that: The ion implantation device used therein comprises a loading chamber (4), a vacuum transmission chamber (6) and a process chamber (7) which are connected in sequence, a transmission robot (3) is located in the vacuum transmission chamber (6), and a scanning robot (1) is located in the process chamber (7).

Images