CN116779402A - Ion implanter and ion beam monitoring and modulating method - Google Patents

Abstract

The application discloses an ion implanter and an ion beam monitoring and modulating method. In order to solve the problem that the ion implanter in the prior art is difficult to realize real-time monitoring and modulation in the process of implanting the ion beam into the silicon wafer, the device comprises an analyzer magnet, wherein a magnetic field space is arranged in the analyzer magnet, the ion beam is emitted after reaching an ion beam outlet through the magnetic field space, and a plurality of conductive structures are arranged at the ion beam outlet and are coupled with measuring equipment; the method comprises injecting an ion beam from an ion source into a magnetic field space inside an analyzer magnet through an ion beam inlet, and emitting the ion beam through an ion beam outlet; the ion beam at the ion beam outlet is measured and modulated in real time by the conductive structure and then projected to the receiving wafer along the desired trajectory. The deflection of the ion beam output from the analyzer magnet from the desired trajectory can be corrected by monitoring the ion beam deflection in real time so that it is implanted into the silicon wafer in the desired trajectory.

Description

Ion implanter and ion beam monitoring and modulating method

Technical Field

The application relates to the field of ion beam monitoring of ion implanters, in particular to an ion implanter and an ion beam monitoring and modulating method.

Background

Conventional ion implanters typically employ faraday cups to monitor the ion beam, and this method can only be accomplished when the ion beam is not implanted into a wafer if real-time monitoring of the ion beam is to be achieved. Therefore, real-time monitoring of the stability of multiple ion beams in size and direction during ion beam implantation into a silicon wafer is difficult to achieve, and real-time adjustment of offset ion beams is also difficult to achieve.

For example, an apparatus for monitoring an ion beam, an apparatus for controlling an ion beam, and a method thereof disclosed in chinese patent document, publication No. CN111263972B, the apparatus includes: a processor; and a memory unit coupled to the processor, the memory unit including a display routine, wherein the display routine is capable of running on the processor to manage monitoring of the ion beam. The display routine includes a measurement processor to receive a plurality of spot beam profiles of the ion beam, the spot beam profiles being collected during a fast scan of the ion beam and a slow mechanical scan of the detector performed concurrently with the fast scan. The fast scan includes a plurality of scan cycles performed at a frequency of 10Hz or greater than 10Hz along the fast scan direction, and the slow mechanical scan is performed in a direction parallel to the fast scan direction. The measurement processor may also send a display signal to display at least one set of information derived from the plurality of spot beam profiles. According to the scheme, the mobile phone ion beam operation outline is scanned mechanically at a low speed, so that the implanted ion beam is monitored in real time to a certain extent, but depending on the operation of a scanning machine, the monitoring efficiency is low, the monitoring effect is still defective, and in addition, the offset ion beam cannot be adjusted in real time.

Disclosure of Invention

The application mainly solves the problem that the ion implanter in the prior art is difficult to realize real-time monitoring and modulation in the process of implanting the ion beam into the silicon wafer; an ion implanter and an ion beam monitoring and modulating method are provided, wherein the ion beam is measured by adopting a traditional Faraday cup, and meanwhile, the running real-time monitoring and modulating of the ion beam is realized by arranging a plurality of conductive structures which are arranged and distributed in a preset manner to compare the offset ion beam current generated by ions striking an analyzer magnet; i.e., the deflection of the ion beam output from the analyzer magnet from the desired trajectory is corrected by monitoring the ion beam deflection in real time so that it is implanted into the silicon wafer in the desired trajectory.

The technical problems of the application are mainly solved by the following technical proposal:

the ion implanter of the present application comprises: the analyzer magnet is internally provided with a magnetic field space, the ion beam is emitted after reaching an ion beam outlet through the magnetic field space, and a plurality of conductive structures are arranged at the ion beam outlet and are coupled with the measuring equipment. The conductive structures described in the present application are typically disposed near the boundary of the beam exit, with each conductive structure being electrically isolated from the other conductive structures and the analyzer magnet. Any current present on each conductive structure is measured continuously in real time during ion implantation into the wafer, i.e., the receiving wafer, so that all collision results between the conductive structure and the ion beam are monitored in real time and transmitted to the measurement device. By properly adjusting the shape, position or number of the conductive structures, the relative geometrical relationship between the conductive structures and the expected track is properly adjusted, so that the real-time monitoring of the deflection angle and the deflection direction of the ion beam is realized. The ion beam current monitoring device can realize real-time monitoring when the ion beam current is injected into the silicon wafer, ensures the stability of the ion beam current in the size and direction in the injection process, and has obvious progress compared with the traditional implanter which only adopts the Faraday cup measurement mode.

Preferably, the analyzer magnet further comprises an ion beam inlet arranged at one end of the analyzer magnet, an ion beam outlet is arranged at the other end of the analyzer magnet, and a shell is wrapped outside the analyzer magnet to form a magnetic field space inside the analyzer magnet; an ion beam is injected from an external ion source through an ion beam inlet and projected from an ion beam outlet onto a receiving wafer. The ion beam inlet and the ion beam outlet are used for limiting the running track of the ion beam, and the internal magnetic field space can change the running direction of the ion beam, so that the effect of fine adjustment on the track of the ion beam is achieved in the running process of the ion beam; the receiving wafer generally adopts a silicon wafer in practical application, the above arrangement of the scheme can meet the application scene of the universal implanter, and the adaptation to each application scene or application equipment is realized through internal fine tuning.

Preferably, the path of the ion beam projected to the receiving wafer along the ion beam outlet is set as a desired path; at least one conductive structure is disposed on the analyzer magnet parallel to the desired trajectory; an isolation material is also disposed between the housing and the conductive structure, which is a non-metallic conductive material attached to the housing and/or a structure formed by a combination of several non-technical conductive materials. The expected track is a manually preset track, so that the ion beam can be implanted into the silicon wafer to the greatest extent according to the predicted situation, and loss is reduced; the conductive structure is used for monitoring the collision size of offset ions in the ion beam and the analyzer magnet so as to know the offset angle and the offset amount of the ion beam; the isolation material is used for reducing the mutual interference between the internal magnetic field and the external magnetic field or equipment, so that the monitoring result is more accurate; the arrangement of the conductive structures is diversified, any form or any independent structure which can play a corresponding role can be adopted, so that the scheme is highly adaptive to the prior art, and the practicability of the scheme is improved.

Preferably, the conductive structure should satisfy one or more of the following settings: at least one conductive structure is disposed only within the ion beam outlet; at least one conductive structure disposed outside the ion beam outlet and facing the receiving wafer; at least one conductive structure is disposed outside the housing. The conductive structure arranged outside the ion beam outlet can monitor the offset and the offset condition of the ion beam in the ion beam outlet, the conductive structure arranged outside the ion beam outlet can monitor the offset ion beam information on the running track of the ion beam, the conductive structure arranged outside the shell can monitor the ion beam part with extremely large offset, and the real-time monitoring of the offset condition of the ion beam is realized to the maximum extent through the mutual combination of the three designs.

Preferably, the conductive structure should also satisfy one or more of the following settings: at least one conductive structure disposed outside the ion beam outlet does not overlap the cross section of the ion beam outlet; providing at least one conductive structure external to the housing that completely overlaps or partially overlaps the cross-section of the ion beam outlet; the cross-section is perpendicular to the desired trajectory. The conductive structure which is not overlapped with the cross section of the ion beam outlet is used for measuring ion collision which generates offset in the inclined direction, and the conductive structure which is overlapped with the cross section of the ion beam outlet is used for measuring ion collision which generates tiny offset on the cross section of the conductive structure, so that finer measurement data can be obtained, and the accuracy of measurement results can be improved.

Preferably, the conductive structure should also satisfy one or more of the following settings: the cross-sectional width of the annular conductive structure is adapted to the diameter of the ion beam; the conductive structures are arranged around the desired track in a manner including forming concentric rings, arrays and/or concentric arcs around the desired track. The arrangement of the annular conductive structure can simultaneously monitor the ion collision amounts received by different parts of the ring, and the collision conditions of the ion beam in all directions of the ion beam outlet can be obtained through integrated analysis, namely the running offset of the ion beam is obtained, so that the follow-up adjustment of the running track of the ion beam is facilitated; the conductive structures are arranged according to different arrays to form concentric rings, concentric arcs and the like, so that the deflection condition and deflection angle of the ion beam can be measured to the greatest extent, the conductive structures are arranged according to the arrays, the measurement results of each part can be mutually noninterfered, and the measurement accuracy is guaranteed to the greatest extent.

The ion beam monitoring and modulating method comprises the following steps: the ion beam is injected into a magnetic field space in the analyzer magnet through an ion beam inlet by an ion source and is emitted through an ion beam outlet; the ion beam at the ion beam outlet is measured and modulated in real time by the conductive structure and then projected to the receiving wafer along the desired trajectory. The method can be used to monitor the real-time condition of the ion beam by comparing the offset beam current generated by the impact, analyzer magnet to monitor the offset condition of the ion beam, thereby achieving control of the ion beam by changing internal operating conditions; the impact can be in the form of ion impact, and the internal operation condition can be magnetic field change caused by current change and voltage change, or ion beam injection angle or implantation angle.

Preferably, the conductive structure transmits impact data generated by the conductive structure and the deflected ion beam part to the measurement equipment, calculates the offset of the actual ion beam track and the expected track after the measurement result is obtained, and adjusts the running angle of the ion beam according to the offset. In practical application, the shape, the number and the size of the conductive structures are set to monitor the offset ions in the ion beam, and the running angle of the ion beam is adjusted after the accurate offset is obtained, so that the ion beam runs according to the expected track.

Preferably, the step of modulating the angle of travel of the ion beam satisfies one or more of the following: changing magnetic field conditions in the magnetic field space so as to modulate the offset angle of the ion beam; adjusting the receiving wafer geometry; the angle and corresponding parameter values of the ion source implant beam are maintained or adjusted. The three modes are arranged and combined to obtain a plurality of different modulation schemes, so that the modulation of the running angle of the ion beam is realized more in a plurality of modes.

The beneficial effects of the application are as follows:

according to the ion implanter and the ion beam monitoring and modulating method, the conductive structures with different numbers, shapes and sizes are arranged at the ion beam outlet, so that the offset and the offset angle of the running track and the expected track of the ion beam in space are monitored, and the real-time monitoring of the ion beam is realized;

2. according to the ion implanter and the ion beam monitoring and modulating method, the obtained offset and offset angle data are matched to adjust the magnetic field space, the injection angle or the receiving wafer angle, so that the ion beam running angle and the track are modulated in the process of implanting the ion beam into the wafer, and the purpose of correcting the track in real time is achieved.

Drawings

FIG. 1 is a block diagram of an ion implanter and an ion beam monitoring modulation method of the present application;

FIG. 2 is a schematic diagram of an ion beam monitoring modulation method of an ion implanter and an ion beam monitoring modulation method of the present application;

ion beam, 202, receiving wafer, 210, ion source, 220, analyzer magnet, 221, ion beam inlet, 222, ion beam outlet, 223, magnetic field space, 224, housing, 225, conductive structure, 226, measurement equipment.

Detailed Description

The technical scheme of the application is further specifically described below through examples and with reference to the accompanying drawings.

Examples:

as shown in fig. 1, the ion implanter in the application scenario mainly includes an ion source 210, an analyzer magnet 220 and a measurement device 226. Wherein the analyzer magnet has a housing 224 enclosing a magnetic field space 223, and an ion beam inlet 221 and an ion beam outlet 222 for allowing the ion beam to pass through. The analyzer magnet also has at least one electrically conductive structure 225 that is generally adjacent to the boundary of the ion beam exit and electrically isolated from the housing. Each conductive structure is electrically coupled to a measurement device for monitoring in real time the current generated by collisions between the conductive structure and the deflected ion beam 210, the ion beam steering monitoring may be achieved by comparing the offset ion beam current generated from ions striking the analyzer magnet.

In detail, the analyzer magnet 220 is provided with a magnetic field space 223 inside, through which the ion beam 201 is emitted after reaching the ion beam outlet 221, where a number of conductive structures 225 are provided, which are coupled with a measuring device 226. The analyzer magnet 220 also includes an ion beam inlet 221 disposed at one end thereof, and an ion beam outlet 221 disposed at the other end of the analyzer magnet. The analyzer magnet is wrapped by a set housing 224, inside which a magnetic field space 223 is formed; the ion beam 226 is incident from the external ion source 210 through the ion beam entrance and projected from the ion beam exit to the receiving wafer 202. The trajectory along which the ion beam 201 is projected to the receiving wafer 202 along the ion beam outlet 221 is set to be a desired trajectory; at least one conductive structure 225 is disposed on the analyzer magnet 220 parallel to the desired trajectory; an insulating material is also provided between the housing and the conductive structure, which is a structure formed by a combination of non-metallic conductive material and/or several non-technical conductive materials attached to the housing.

Wherein the conductive structure 225 should satisfy one or more of the following specific settings: at least one conductive structure is disposed only within the ion beam outlet 221; at least one conductive structure disposed outside the ion beam outlet and toward the receiving wafer 202; at least one conductive structure is disposed outside the housing. The conductive structure 225 should also satisfy one or more of the following settings: at least one conductive structure disposed outside the ion beam outlet 221 does not overlap the cross-section of the ion beam outlet; providing at least one conductive structure external to the housing that completely overlaps or partially overlaps the cross-section of the ion beam outlet; the cross section is perpendicular to the desired trajectory; one and only one of the conductive structures is arranged in a ring shape around the desired trajectory, and the cross-sectional width of the ring-shaped conductive structure is adapted to the diameter of the ion beam 201; the conductive structures are arranged around the desired track in a manner including forming concentric rings, arrays and/or concentric arcs around the desired track.

As shown in fig. 2, the ion beam monitoring modulation method of the present embodiment includes the following steps: first, an ion beam is provided through a beam outlet of an analyzer magnet; next, the current present on at least one conductive structure near the beam exit boundary is measured, wherein each conductive structure is electrically isolated from other portions of the analyzer magnet, including other conductive structures. The deflection of the ion beam is then monitored in real time by analyzing the current in real time, so that the implanter can be adjusted to adjust the ion beam implantation direction. In other words, it can be described as: the ion beam is injected into a magnetic field space in the analyzer magnet through an ion beam inlet by an ion source and is emitted through an ion beam outlet; the ion beam at the ion beam outlet is measured and modulated in real time by the conductive structure and then projected to the receiving wafer along the desired trajectory.

Specifically, the conductive structure transmits impact data generated by the conductive structure and the deflected ion beam part to the measurement equipment, calculates the offset of the actual ion beam track and the expected track after the measurement result is obtained, and adjusts the running angle of the ion beam according to the offset. The step of modulating the ion beam angle of travel satisfies one or more of the following: changing an ion beam deflection angle in a magnetic field control analyzer magnet in a magnetic field space; adjusting the receiving wafer geometry; the angle and corresponding parameter values of the ion source implant beam are maintained or adjusted.

In summary, the present embodiment monitors and controls the ion beam in real time by comparing the offset beam current produced by the impact analyzer magnet. The method principle and the ion implanter in the embodiment are combined and applied in the following steps:

the ion implanter of this embodiment comprises an ion source, an analyzer magnet and a measurement device; the analyzer magnet has a housing enclosing a magnetic field space, a beam inlet and a beam outlet for allowing passage of an ion beam; the analyzer magnet also has at least one electrically conductive structure adjacent to the boundary of the beam outlet and electrically insulated from the housing. Furthermore, each conductive structure is electrically coupled to a measuring device for monitoring in real time the current generated by collisions between the conductive structure and the deflected ion beam. Thus, beam steering control is achieved by comparing the offset beam current produced from ions striking the analyzer magnet.

Providing an ion beam through a beam outlet of an analyzer magnet; next, the current present on at least one conductive structure near the beam exit boundary is measured, wherein each conductive structure is electrically isolated from other portions of the analyzer magnet, including other conductive structures. When the ion beam does not pass completely through the beam exit, some of the ions will collide with the conductive structure and induce a current on the conductive structure. Thus, by monitoring the current of each conductive structure individually in real time, the actual trajectory of the ion beam can be monitored in real time using the conductive structure disclosed in accordance with the present embodiment, due to the general/basic operation and configuration of the conductive structures that may be known.

In addition, after the actual running track of the ion beam is monitored in real time, the actual injection result on the silicon wafer can be monitored in real time. Thus, at least one actual parameter value of one or more of the ion implanter or the implantation process may be adjusted such that the actual trajectory of the ion beam is adjusted, matched or better conforms to the desired trajectory. Of course, if the cost/difficulty required to adjust the true trajectory is high, the geometry of the wafer may also be adjusted so that the implantation result of the ion beam along the true trajectory is equal or more consistent with the implantation result of the ion beam along the desired trajectory.

It should be understood that the examples are only for illustrating the present application and are not intended to limit the scope of the present application. Furthermore, it should be understood that various changes and modifications can be made by one skilled in the art after reading the teachings of the present application, and such equivalents are intended to fall within the scope of the application as defined in the appended claims.

Claims (9)

1. An ion implanter comprising an analyser magnet (220) wherein a magnetic field space (223) is provided within the analyser magnet and an ion beam (201) is ejected through the magnetic field space to an ion beam outlet (221) where a plurality of electrically conductive structures (225) are provided, the electrically conductive structures being coupled to a measurement device (226).

2. The ion implanter of claim 1, wherein the analyzer magnet (220) further comprises an ion beam inlet (221) disposed at one end thereof, the other end of the analyzer magnet being provided with an ion beam outlet (221), the analyzer magnet being wrapped with a housing (224) defining a magnetic field space (223) therein; an ion beam (226) is injected from an external ion source (210) through an ion beam entrance and projected from an ion beam exit onto a receiving wafer (202).

3. An ion implanter according to claim 1 or 2, wherein the trajectory along which the ion beam (201) is projected along the ion beam exit (221) to the receiving wafer (202) is set to a desired trajectory; at least one electrically conductive structure (225) is disposed on the analyzer magnet (220) parallel to the desired trajectory; an isolation material is also disposed between the housing and the conductive structure, which is a non-metallic conductive material attached to the housing and/or a structure formed by a combination of several non-technical conductive materials.

4. An ion implanter according to claim 3, wherein the conductive structure (225) is configured to satisfy one or more of the following: at least one conductive structure is disposed only within the ion beam outlet (221); at least one conductive structure disposed outside the ion beam outlet and facing the receiving wafer (202); at least one conductive structure is disposed outside the housing.

5. An ion implanter according to claim 4, wherein the conductive structure (225) is further configured to satisfy one or more of the following: at least one conductive structure disposed outside the ion beam outlet (221) does not overlap the cross section of the ion beam outlet; providing at least one conductive structure external to the housing that completely overlaps or partially overlaps the cross-section of the ion beam outlet; the cross-section is perpendicular to the desired trajectory.

6. An ion implanter according to claim 5, wherein the conductive structure (225) is further configured to satisfy one or more of the following: the conductive structures, one and only, are arranged in a ring around a desired trajectory, the cross-sectional width of the ring-shaped conductive structure being adapted to the diameter of the ion beam (201); the conductive structures are arranged around the desired track in a manner including forming concentric rings, arrays and/or concentric arcs around the desired track.

7. An ion beam monitoring and modulating method suitable for the ion implanter according to any one of claims 1 to 6, characterized in that the ion beam is injected into a magnetic field space inside an analyzer magnet from an ion source through an ion beam inlet and is emitted through an ion beam outlet; the ion beam at the ion beam outlet is measured and modulated in real time by the conductive structure and then projected to the receiving wafer along the desired trajectory.

8. The method of claim 7, further comprising: the conductive structure transmits impact data generated by the conductive structure and the deflected ion beam part to measurement equipment, calculates the offset of the actual ion beam track and the expected track after the measurement result is obtained, and adjusts the running angle of the ion beam according to the offset.

9. The method of claim 8, wherein the step of modulating the ion beam angle of operation satisfies one or more of: changing magnetic field conditions in the magnetic field space so as to modulate the offset angle of the ion beam; adjusting the receiving wafer geometry; the angle and corresponding parameter values of the ion source implant beam are maintained or adjusted.