TWI682420B - Ion implantation system and method with variable energy control - Google Patents

Abstract

An ion implantation system and method for implanting ions at varying energies across a workpiece is provided. The system comprises an ion source configured to ionize a dopant gas into a plurality of ions and to form an ion beam. A mass analyzer is positioned downstream of the ion source and configured to mass analyze the ion beam. A deceleration/acceleration stage is positioned downstream of the mass analyzer. An energy filter may form part of the deceleration/acceleration stage or may positioned downstream of the deceleration/acceleration stage. An end station is provided having a workpiece support associated therewith for positioning the workpiece before the ion beam is also provided. A scanning apparatus is configured to scan one or more of the ion beam and workpiece support with respect to one another. One or more power sources are operably coupled to one or more of the ion source, mass analyzer, deceleration/acceleration stage, and energy filter. A controller is configured to selectively vary one or more voltages respectively supplied to one or more of the deceleration/acceleration stage and the energy filter concurrent with the scanning of the ion beam and/or workpiece support, wherein the selective variation of the one or more voltages is based, at least in part, on a position of the ion beam with respect to the workpiece support.

Description

Ion implantation system and method with variable energy control

The present invention relates generally to ion implantation systems, and more specifically to a system and method for providing selectively controlled variable energy to an ion beam delivered to a workpiece during ion implantation of the workpiece .

Reference to related applications

This application claims the benefits of US Provisional Application No. 61/927,811, entitled "Ion Implantation System and Method with Variable Energy Control", filed on January 15, 2014. The content of this application is here The whole is incorporated as a reference.

In the manufacture of semiconductor devices, ion implantation systems are used to dope semiconductors with impurities. Ion implantation systems are often used to dope a workpiece, such as a silicon or germanium wafer, with ions from the ion beam during the manufacture of an integrated circuit to facilitate the doping of n-type or p-type materials, or Is to form a protective layer. When used to dope semiconductor wafers, the ion implantation system implants a selected ion species into the workpiece to produce the desired electrical characteristics in the base material of the workpiece. For example, an implanted ion system generated from a source material like antimony, arsenic, or phosphorus produces an "n-type" material feature, and a "p-type" material feature is derived from the use of a source material such as boron, gallium, or indium The generated ions.

A typical ion implantation system includes an ion source for generating charged ions from ionizable source materials. The generated ion system is formed into a high-speed ion beam by using a strong electric field to attract ions from the ion source and guide the ions along a predetermined beam path to an implantation terminal station. The implantation terminal station allows the workpiece to be transported in the path of the beam. The ion implanter may include a beam forming and shaping structure extending between the ion source and the terminal station. The beam forming and shaping structures maintain the ion beam and define an elongated internal recess or channel through which the ion beam passes to the terminal station. During operation, this channel is usually evacuated to reduce the probability that ions will deviate from the preset beam path due to collisions with gas molecules.

It is common that the workpiece to be implanted in the ion implantation system is a semiconductor wafer having a size much larger than that of the ion beam. In most ion implantation applications, the goal of implantation is to uniformly deliver a precisely controlled amount of one of the dopants over the entire area of the surface of the workpiece or wafer. In order to achieve the uniformity of doping with an ion beam having a size much smaller than the area of the workpiece, a widely used technique is a so-called hybrid scanning system in which a small-size ion beam is quickly scanned back and forth in one direction or Scanning, and the workpiece is mechanically moved in the direction orthogonal to the scanned ion beam.

Alternatively, a ribbon beam system is known, which provides a longitudinal ion beam from an ion source, where the beam system is allowed to diverge further as it travels toward the workpiece, thereby When the workpiece is mechanically moved in the direction orthogonal to the longitudinal ion beam, ions are spread across the entire width of the workpiece. In yet another alternative, the so-called "pencil beam" system is known, in which the ion beam system is presented to the workpiece in the form of a point, while the workpiece is scanned in two dimensions. This uses the ions from the pen-shaped beam to "paint" The entire wafer.

The ion dose implanted into a workpiece by an ion beam has traditionally been controlled by changes in scanning speed (eg, a speed of the workpiece relative to the ion beam, or vice versa). For example, U.S. Patent No. 4,922,106 issued to Berrian et al. discloses an ion implantation system in which an ion beam is scanned and traversed over a workpiece in a controlled manner to achieve a selected beam current and The corresponding ion dose on the workpiece. Another feature of the Berrian et al. patent is a method and apparatus for sensing the ion beam incident on the workpiece and controlling the exposure of the ion beam to the workpiece, so as to achieve a selected ion dose at the workpiece, Its specific purpose is to obtain a highly uniform dose over the entire surface of the workpiece.

In more elaborate integrated circuit manufacturing techniques, it may be advantageous to control the implantation process by implanting ions in a non-uniform manner for producing multiple regions on the workpiece where different doses are implanted. For example, US Patent No. 6,750,462 issued to Iwasawa et al. discloses an ion implantation method and apparatus in which a plurality of ion implantation steps are performed by changing a driving speed of the workpiece. Furthermore, a rotation step is provided for rotating the workpiece about the center of the workpiece by a specified angle between the individual implantation steps when the ion beam is not applied to the workpiece, in order to provide a span The implanted workpiece with a selectively controlled ion dose on the surface of the workpiece.

Generally, it is desirable to maintain a uniform energy distribution of one of the implanted ions across the surface of a workpiece. However, US Patent No. 7,576,339 issued to Rouh et al. discloses an implantation system with an energy control feature for controlling the ion implantation energy of the ion beam according to the area of the wafer being implanted. As disclosed by Rouh et al., the distribution of ion implantation energy into a wafer is discretely (limitedly) based on discrete or limited areas on the wafer Changes such that the ion system is implanted into a first region with a relatively high implant energy, and the ion system is implanted into a second region with a relatively low implant energy. In an alternative embodiment of Rouh et al., a first discrete area of the wafer is implanted with a discrete low implant energy, and a second discrete area is implanted with a discrete high implant energy, And a third area is again implanted with the low implant energy. Similarly, the ion implantation energy is discretely changed according to discrete regions of the wafer.

The following is a simplified summary of one of the contents of this disclosure in order to provide a basic understanding of some of the features of this disclosure. This summary is not an extensive overview of the invention. It is not intended to point out key or important elements of the invention, nor to describe the scope of the invention. Its purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later.

The present disclosure generally relates to a system, device, and method for continuously changing the energy of ions implanted into a workpiece while a workpiece and an ion beam are translated relative to each other while shifting relative to each other.

An ion implantation system is proposed that includes an ion source configured to ionize a dopant gas into a plurality of ions and form an ion beam; and an ion source disposed downstream of the ion source and configured for mass analysis The mass analyzer of the ion beam. An electrode stage system is provided downstream of the mass analyzer for accelerating or decelerating the ion beam in response to the bias voltage applied thereto. Furthermore, an energy filter is provided for deflecting the ion beam, wherein an output deflection angle can be maintained by selectively changing the bias voltage applied to the energy filter according to the energy of the ion beam . A terminal station is set under the energy filter Where the terminal station has a workpiece support associated with it.

In a preferred embodiment, the present disclosure is further provided with a scanning device configured to scan one or more of the ion beam and/or the workpiece support relative to each other. One or more power supplies are operatively coupled to one or more of the ion source, mass analyzer, electrode stage, and energy filter. A controller is further provided and is configured to selectively change one of the electrode stage and the energy filter to be supplied simultaneously with the scanning of the spot ion beam and/or workpiece support, respectively One or more voltages, wherein the selective change of the one or more voltages depends at least in part on a position of the ion beam relative to the workpiece support.

In another embodiment of the present disclosure, a method for providing selective continuous variable energy ion implantation of a workpiece is proposed. The method includes directing an ion beam toward a workpiece; scanning the ion beam and one or more of the workpiece relative to each other; and selecting simultaneously with the scanning of the spot ion beam and one or more of the workpiece To change the energy of the ion beam. Thus, the depth of ion implantation into one of the workpieces is controlled and selectively changed along a surface of the workpiece in a continuous manner.

100‧‧‧Workpiece

102‧‧‧Oxide layer

104, 104A, 104B ‧‧‧ thickness

106‧‧‧Surface

108‧‧‧ surrounding area

110‧‧‧ peripheral

112‧‧‧ Central area

200‧‧‧Workpiece

202‧‧‧ Scanned ion beam

204‧‧‧ Scanning direction

206‧‧‧Oxide layer

208‧‧‧Depth

210‧‧‧ Edge (periphery)

212‧‧‧Depth

214‧‧‧ Center

216‧‧‧thickness

218‧‧‧thickness

410‧‧‧Ion implantation system

412‧‧‧Terminal

414‧‧‧Bundle assembly

416‧‧‧Terminal

418‧‧‧ slit

420‧‧‧Ion source

421‧‧‧ Production room

422‧‧‧Power supply

423‧‧‧Ion extraction module

424‧‧‧Ion beam

424a~424g‧‧‧small beam

425‧‧‧Extraction/suppression electrode

425a、425b‧‧‧electrode

426‧‧‧Quality Analyzer

427‧‧‧Sidewall

430‧‧‧Workpiece

432‧‧‧beam guide

434‧‧‧Analysis hole

435‧‧‧ Scanning system

436‧‧‧scanning element

436a、436b‧‧‧electrode

437‧‧‧ distance traveled

438‧‧‧focus/guide element/parallelizer

438a, 438b ‧‧‧ electrode

439‧‧‧Parallelizer

439a, 439b ‧‧‧ bipolar magnet

441‧‧‧ scanning vertex

449‧‧‧Power supply

450‧‧‧Power supply

452‧‧‧Dose system

454‧‧‧Control system

456‧‧‧Analyzer

457‧‧‧Acceleration or deceleration/filtration subsystem

457a、457b‧‧‧electrode

458‧‧‧Analyzer path

460‧‧‧waveform

470‧‧‧stepping motor

500‧‧‧electrode column

502‧‧‧First electrode

504‧‧‧Second electrode

506‧‧‧First hole

508‧‧‧Second hole

510‧‧‧Gap

512‧‧‧axis

514‧‧‧ electrode in the gap above

516‧‧‧ electrode in the gap below

518‧‧‧Sub-gap area above the first

520‧‧‧Sub-gap area under the first

522‧‧‧Sub-gap area above the second

524‧‧‧Second sub-gap area

526‧‧‧Ion beam

528‧‧‧

530‧‧‧Neutral area

532‧‧‧ corner

534‧‧‧electrode

536‧‧‧electrode

600‧‧‧Method

602‧‧‧Action

604‧‧‧Action

606‧‧‧Action

608‧‧‧Action

610‧‧‧Action

FIG. 1 is a cross-sectional view of a portion of a workpiece having an oxide layer thereon, which shows the effect of a conventional chemical mechanical planarization or polishing (CMP) process thereon.

FIG. 2 depicts a cross-sectional view of an exemplary workpiece, which is an ion implant with a change in ion energy according to one of the features of the present disclosure, while scanning, to provide a continuously variable depth Ion implantation.

FIG. 3 depicts a cross-sectional view of an example workpiece that has undergone variable depth/energy ion implantation according to the disclosure and a CMP process according to the previous description, which depicts one of the disclosure Favorable application.

FIG. 4 is a block diagram of an ion implantation system according to one example of several features of the present disclosure.

FIG. 5 is a schematic diagram of an exemplary scanner that can be incorporated into an exemplary ion implantation system according to one of several features of the present disclosure.

Figure 6 is a plot of a triangular or "sawtooth" voltage waveform of the type normally applied to the scanner of Figure 5; Figure 7 is a depiction of a single-scan ion beam and its impact on several discrete points in time A perspective view of several discrete points of the workpiece; FIG. 8 is a side view depicting a typical scanning pattern for scanning an ion beam across a surface of a workpiece for ion implantation of the workpiece; FIG. 9 is A graph depicting the deceleration and bending effects produced by an electrode column of the type of deceleration stage/angular energy filter device of an ion implantation device according to an example of another feature of the disclosure.

FIG. 10 depicts a method for changing the energy of a spot-shaped ion beam in a scanning ion beam implanter according to yet another feature.

This disclosure generally relates to a system, device, and method for changing the energy of an ion beam in an ion implantation system. In a particular embodiment, the system, apparatus, and method for changing the energy of the ion beam incorporates a scan of the type developed, manufactured, and sold by Excellus Technology Corporation of Beverly, Massachusetts Pen shot Beam system architecture. However, it is also contemplated that the present disclosure can be implemented in a generally known ribbon beam or pencil beam ion implantation system architecture, as will be described further.

This disclosure can be applied to various ion implanters, and is considered for implementation in various ion implanters. For example, this disclosure can be applied to three types of ion implanters: those that use an ion beam that sweeps a workpiece in two dimensions, where a ribbon ion beam is defined as having A longitudinal dimension is larger than a width of the workpiece irradiated with the ion beam; those using an ion beam having a relatively static cross-sectional dimension and in which the workpiece is moved in two dimensions relative to the ion beam Implanters; and those using a hybrid system of ion implanters, wherein the ion beam is oscillated or scanned relative to the workpiece along a first direction, and the workpiece is along a first direction transverse to the first direction Moved in two directions.

The disclosed variable control of the selectivity of the energy distribution in the ion implantation process has not yet been revealed or considered, especially the choice of implantation energy in a continuous way across the surface of a target workpiece Variable control of sex. Therefore, the present disclosure provides a system, device, and method for changing the energy distribution of ions implanted by an ion beam across the workpiece in a continuous manner.

This disclosure provides a solution to a specific problem that exists in advanced integrated circuit manufacturing. Recently, the integrated circuit manufacturing industry has adopted adaptive patterning processes, which in many cases rely on auxiliary processes for removing materials deposited on a semiconductor workpiece. For example, a silicon wafer may be provided with an oxide layer (or a polysilicon or nitride layer), which may be exposed to an implantation step, for example via hydrogen (for example, it is commonly used for exfoliation Surface) or via reactive ions such as fluorine or chlorine (for example, it is commonly used to change the chemical composition of the oxide layer). A preferred process for removing material deposited on a semiconductor workpiece is the so-called chemical mechanical planarization or polishing (CMP), which is a process that uses a combination of chemical and mechanical forces to smooth the surface. CMP can be thought of as a mixture of chemical etching and free abrasive polishing, and is a preferred method for removing material from a substrate in a planar and uniform manner because, among other things It provides accuracy and repeatability, such as the ability to stop material removal at important interfaces between copper and oxide insulating layers formed on a semiconductor wafer.

Despite the various advantages of this process, the CMP process still suffers from not always removing certain material layers uniformly across the surface of the wafer. More specifically, it has been found that the removed coating (for example, usually an oxide layer) may have a curved profile, which is thicker in the middle of the wafer and thinner on the edges. It produces a convex surface layer.

The present disclosure currently recognizes that by subjecting the layer to an ion implantation step before a CMP step, the resulting CMP-treated layer can have a more uniform thickness. In particular, the ion implantation of the layer to be removed can change the removal rate of the CMP material. More specifically, the material removal rate can be adjusted by the depth of ion implantation, so the depth of ion implantation is directly proportional to the energy of the implanted ions.

A similar method can also be applied to a controlled etching process for smoothing the surface of a workpiece when an uneven layer is formed between the workpieces. Depending on the thickness of the surface layer, different energies are transferred to different parts of the workpiece. Ion implantation can modify the material etching rate at different depths. Therefore, the final depth of the etch-removed layer at different wafer positions can be controlled in proportion to the original non-uniformity, and thus produces a more uniform after etching Floor.

Therefore, the present disclosure advantageously solves the problems in the field of material modification, thereby enabling advanced integrated circuit manufacturing technology. Regarding the specific solution contemplated by the inventors, FIGS. 1-3 are provided as illustrative examples. For example, FIG. 1 depicts a workpiece 100, such as a conventional silicon wafer of the type used as a workpiece substrate in the first step of a semiconductor process. In the example illustrated here, an oxide layer 102 having a predetermined thickness 104 has been formed on the surface 106 of the workpiece 100. This oxide layer 102 can then be processed by CMP to achieve the specified characteristics.

A typical CMP process uses an abrasive and corrosive chemical slurry (eg, a colloid) combined with a polishing pad. The polishing pad and workpiece 100 are pressed together by a dynamic polishing head, which rotates with different axes of rotation (ie, non-concentric). The goal of the CMP process is to remove material and smooth out any irregular surface configuration, thus making the wafer flat or planar, which is sometimes necessary to prepare the wafer for additional Subsequent formation of circuit elements. For example, the CMP process can be performed so that the entire surface is within the depth of field of a lithography system, or the material is selectively removed according to location.

Although the CMP process is effective in removing material, it has been found that a center-to-edge thickness non-uniformity can occur in a residual layer remaining on the workpiece 100. As depicted in FIG. 1, this problem manifests itself in a substantially convex oxide layer 102. For example, the oxide layer 102 after the CMP process is thin in a peripheral region 108 close to the periphery 110 of the workpiece 100 (eg, depicted as a thickness 104A), and in a central region 112 close to the center of the workpiece It is thicker (for example, depicted as thickness 104B). In order to solve this problem, this disclosure specifically considers a variable depth for implanting ions in the oxide layer System and method for changing the material removal rate of CMP.

The depth of ion implantation is directly related to the energy of the implanted ions. By controlling the depth of ion implantation in a manner that corresponds to a desired CMP removal rate modification, the present disclosure advantageously modifies the material removal across the surface of the wafer to provide the desired uniform thickness and Its surface configuration. Therefore, as depicted in the workpiece 200 of the example of FIGS. 2 and 3, the characteristics of an example of the present invention are considered, in which the ions are treated at a shallow depth 208 along an edge or periphery 210 of the workpiece Implanted (for example, a scanned ion beam is depicted as arrow 202 in FIG. 2 which travels in a scanning direction 204 relative to the workpiece) into an oxide layer 206, and the ions are directed toward a The center 214 is implanted with a larger depth 212. Therefore, after the subsequent chemical mechanical polishing of the oxide layer 206, a thickness 216 of the oxide layer can be made to be uniform across the workpiece 200 from the edge or periphery 210 to the center 214, as shown in the figure A polished thickness 218 depicted in 3. Such variable depth ion implantation is enabled by a system and method of the present disclosure for providing a continuous selective change of the ion implantation energy in an ion implantation.

It will be understood that the previous application is only one of various processes and applications enabled by the continuous and variable depth ion implantation system and method of the present disclosure. The scope of this disclosure and the scope of the patent application are not limited to the solution to this problem, nor is it limited to a variable shape used in the shape of a convex surface of a workpiece, a concave surface or any other shape or other contour Deep implantation process. The variable, continuous, and non-uniform ion energy implantation process of the present disclosure can be implemented in any manner as required to provide a continuous process in addition to a non-continuous variable implantation depth profile Variable implant depth profile. For example, it is thought that the content of this disclosure can be selectively Changes are utilized in any desired application where the depth of ion implantation with variable selectivity is desired. There may be some reasons for implantation at different depths/energy across the surface of a workpiece, including but not limited to: changes in the critical voltage across the workpiece; implantation across the scan width of the workpiece The contour of the system changes on the energy profile; and the ability to implant multiple dies with different electrical characteristics on a single wafer.

Therefore, in order to achieve the aforementioned and related purposes, the present invention includes the features fully described below and particularly pointed out in the scope of the patent application. The following description and accompanying drawings illustrate some of the illustrated embodiments of the present invention in detail. However, these embodiments are only a few of the various ways in which the principles of the present invention can be adopted. Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description of the present invention when considered in conjunction with the drawings.

Therefore, the present invention will now be described with reference to the drawings, in which the same element symbols may be used to refer to similar elements throughout. It should be understood that the descriptions of these features are only examples, and they should not be interpreted in a restrictive sense. In the following description, for the purpose of understanding, many specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be implemented without these specific details.

FIG. 4 depicts an exemplary ion implantation system 410 in which ion beam energy can be selectively changed and/or controlled as described herein. The system 410 has a terminal 412, a harness assembly 414, and a terminal station 416. The terminal 412 includes an ion source 420 powered by a high-voltage power supply 422, which generates and directs an ion beam 424 to the beam assembly 414. In this regard, the ion source 420 generates charged ions, which are derived from The source is extracted via extraction assembly 423 and forms the ion beam 424, which is then directed to the terminal station 416 along a beam path in the beamline assembly 414.

In order to generate ions, a dopant material (not shown) to be ionized is disposed within a generation chamber 421 of the ion source 420. For example, the dopant material can be fed into the chamber 421 from a gas source (not shown). In one example, in addition to the power supply 422, it will be appreciated that any number of suitable mechanisms (not shown) can be utilized to excite free electrons in the ion generating chamber 421, such as RF or A microwave excitation source, an electron beam injection source, an electromagnetic source, and/or a cathode that generates an arc discharge in the chamber. The excited electron system collides with the dopant gas molecules, thereby generating ions. In general, positive ions are generated, although the disclosure herein can also be applied to systems in which negative ions are generated.

The ion systems are controllably drawn through a slit 418 in the chamber 421 through an ion extraction assembly 423, where the ion extraction assembly includes a plurality of extraction and/or suppression electrodes 425. For example, the ion extraction assembly 423 may include another extraction power supply (not shown) to bias the extraction and/or suppression electrodes 425 for accelerating the ions from the generation chamber 421. It can be appreciated that since the ion beam 424 includes the same charged particles, the ion beam may have a tendency to expand radially outward or the beam "expands" because the same charged particles will repel each other within the ion beam . It can also be appreciated that the phenomenon of beam expansion may be exacerbated in low-energy, high-current (eg, high conductivity) beams, where many of the same charged particles move relatively slowly in the same direction There is a large amount of repulsive force between the particles, but there is a small particle momentum to keep the particles moving in the direction of the beam path.

Therefore, the extraction component 423 is generally configured such that the ion beam 424 is It is extracted with high energy so that the ion beam does not expand (for example, so that the particles have sufficient momentum to overcome the repulsive force that may cause the beam to expand). Furthermore, it is generally advantageous to transmit the ion beam 424 with a relatively high energy in the entire system, where this energy can be reduced as needed just before the ions are implanted into the workpiece 430 to improve the beam protection Containment. It may also be advantageous to generate and transport molecules or cluster ions, which can be transported at a relatively high energy, but implanted with a lower equivalent energy, because the energy of the molecule or cluster is dispersed in the doping of the molecule Between atoms.

The beam assembly 414 includes a beam guide 432, a mass analyzer 426, a scanning system 435, a parallelizer 439, and one or more acceleration or deceleration and/or filtering subsystems 457. The mass analyzer 426 is configured to have an angle of about ninety degrees, and includes one or more magnets (not shown) that act to establish a (bipolar) magnetic field therein. When the ion beam 424 enters the mass analyzer 426, it is bent accordingly by the magnetic field, so that the desired ions are transmitted along the beam path, and ions with an inappropriate charge-to-mass ratio are rejected . More specifically, ions with a too large or too small charge-to-mass ratio will be deflected insufficiently or excessively so as to be guided into the sidewall 427 of the mass analyzer 426, so the mass analyzer is allowed to The ions in the ion beam 424 that have the desired charge-to-mass ratio can pass therethrough and exit through a resolution hole 434.

A scanning system 435 is further described, wherein the scanning system includes, for example, a scanning element 436 and a focusing and/or guiding element 438. The scanning system 435 may include various scanning systems, such as U.S. Patent No. 4,980,562 issued to Berrian et al., 5,091,655 issued to Dykstra et al., 5,393,984 granted to Glavish, 7,550,751 granted to Benveniste et al., and 7,615,763 granted to Vanderberg et al. The exhibitors in the Lee's overall is hereby included as a reference.

In the scanning system 435 of this example, the individual power supplies 449, 450 are operatively coupled to a scanning element 436 and a focusing and guiding element 438, and more specifically to the individual located therein Electrodes 436a, 436b and 438a, 438b. The focusing and guiding element 438 receives a mass-analyzed ion beam 424 with a relatively narrow profile (eg, a "pen" beam in the illustrated system 410), one of which is powered by a power supply 450 The voltages applied to the plates 438a and 438b operate to focus and direct the ion beam to an optimal point of the scanning element 436, preferably a scanning vertex 441. A voltage waveform applied to the scanner boards 436a and 436b by the power supply 449 (for example, the power supply 450 can also be used as the power supply 449) is then scanned back and forth of the ion beam 424 to The ion beam 424 unfolds into an elongated "ribbon" beam (eg, a scanned ion beam 424) having a width that can be at least as wide as or wider than the workpiece of interest. It will be appreciated that the scanning vertex 441 can be defined as being in the optical path, each beamlet or scanned portion of the ribbon beam is seen after having been scanned by the scanning element 436 The point from which it rises.

It will be appreciated that an ion implantation system of the type described herein can utilize different types of scanning systems. For example, an electrostatic system or a magnetic system can be adopted in the present invention. A typical embodiment of an electrostatic scanning system includes a power supply coupled to the scanner board or electrodes 436a and 436b, wherein the scanner 436 provides a scanning beam. The scanner 436 receives a mass-analyzed ion beam with a fairly narrow profile (for example, a "pen" beam in the illustrated system), and is applied by the power supply 449 The voltage waveforms to the scanner boards 436a and 436b operate to come in the X direction (the scanning direction) Scan the beam back to expand the beam into an elongated "ribbon" beam (eg, a scanned beam) with an effective X-direction width that can be at least the same as the workpiece of interest Wider, or wider than the workpiece. Similarly, in a magnetic scanning system, a high current supply is connected to the coil of an electromagnet. The magnetic field is adjusted to scan the beam. For the purpose of this disclosure, all types of scanning systems are considered, and the electrostatic system is used for illustration. The scanned ion beam 424 then passes through a parallelizer 438 that directs the beam toward the end station 416 substantially parallel to the Z direction (eg, substantially perpendicular to the workpiece surface).

5-6, the electrostatic version of the beam scanner 436 is further depicted in FIG. 5, which has a pair of scanning plates or electrodes 436a and 436b on both lateral sides of the beam path, and a The voltage source 450 of the AC voltage to the electrodes 436a and 436b is as shown in the waveform diagram 460 of the "sawtooth wave type" in FIG. A time-varying voltage between scan electrodes 436a and 436b produces a time-varying electric field across the beam path between them, and the beam is along a scanning direction by the electric field (e.g. (X direction in 5) is bent or deflected (for example, scanning). When the scanner electric field is in the direction from the electrode 436a to the electrode 436b (for example, the potential of the electrode 436a is more positive than the potential of the electrode 436b, for example, at times "e", "f", and "g in FIG. 6 "), the positively charged ions of the ion beam 424 are subjected to a lateral force in the negative X direction (eg, toward the electrode 436b). When the electrodes 436a and 436b are at the same potential (for example, the zero electric field in the scanner 436, for example, the time "d" in FIG. 6), the ion beam 424 passes through the scanner unmodified 436. When the electric field is in the direction from electrode 436b to electrode 436a (for example, at times "a", "b", and "c" in FIG. 6), the positively charged ions of the ion beam 424 are at positive X A lateral force is applied in the direction (for example, toward the electrode 436a). For illustrative purposes, FIG. 5 shows when the scanned ion beam 424 passes through several discrete points in time during the scan The deflection of the scanner 436, where the extreme beamlets 424a and 424g are marked to correspond to the times "a" and "g" of FIG.

Low-energy implanters are usually designed to provide ion beams from several thousand electron volts (keV) to as high as about 80-100keV, while high-energy implanters can be located between mass analyzer 426 and end station 416 of FIG. An RF linear acceleration (linac) device (not shown) is used to accelerate the mass-analyzed ion beam 424 to a higher energy, usually several hundred keV, where DC acceleration is also feasible. High energy ion implantation is usually the deeper implant used in the workpiece 430. Conversely, the high current, low energy (high conductivity) ion beam 424 is usually used for high dose, shallow depth ion implantation. In this case, the high conductivity of the ion beam is usually maintained The uniformity of the ion beam 424 causes difficulties.

Referring again to FIG. 4, the scanned ion beam 424 then passes through the parallelizer 439. Various parallelizer systems 439 are shown by US Patent Nos. 5,091,655 to Dykstra et al., 5,177,366 to Dykstra et al., 6,744,377 to Inoue, 7,112,809 to Rathmell et al., and 7,507,978 to Vanderberg et al. The entirety of the US patent is hereby incorporated by reference. As the name implies, the parallelizer 439 causes the pen-shaped beam with the incoming rays of diverging rays or beamlets to be deflected into parallel rays or beamlets 424a so that the implant across the workpiece 430 The input parameters (eg, implantation angle) are uniform. In the presently depicted embodiment, the parallelizer 439 includes two bipolar magnets 439a, 439b, where the bipoles are substantially trapezoidal and are oriented to mirror each other so that the ion beam 424 is bent into one The substance is "s-shaped". In a preferred embodiment, the bipolar systems have equal angles and opposite bending directions.

The main purpose of the dipoles is to convert the complex number derived from the scan vertex 441 The divergent rays or beamlets become a plurality of substantially parallel rays or beamlets in the form of a relatively thin, elongated ribbon beam. The use of two symmetrical dipoles as depicted here produces a symmetrical characteristic across the ribbon beam in terms of small beam path length and first-order and higher-order focusing properties. Furthermore, similar to the operation of the mass analyzer 426, the s-shaped bending system acts to purify the ion beam 424. In particular, the trajectories of neutral particles and/or other contaminants (eg, environmental particles) entering the ion beam 424 downstream of the mass analyzer 426 are generally not affected by the bipolar (or have very little effect) , So that these particles continue to travel along the original beam path, and therefore are not bent or are bent very small. A considerable amount of these neutral particles will not affect the workpiece 430 (for example, the workpiece is Set to receive the curved ion beam 424). It can be appreciated that it is important to remove such contaminants from the ion beam 424 because they may have an incorrect charge, etc. Generally speaking, such pollutants will not be affected (or by a very small degree) by the deceleration and/or other levels in the system 410. In this regard, they may have a significant (though unintentional and generally undesirable) effect on the workpiece 430 in terms of dose and angular uniformity. As a result, this may produce unexpected and undesirable device performance.

FIG. 7 depicts that the scanned and parallelized ion beam 424 affects the workpiece 430 at the corresponding time indicated in FIG. 6. For a single substantially horizontal scan across the workpiece 430 in the X direction, the scanned and parallelized beamlet 424a in FIG. 7 is applied corresponding to the time "a" in FIG. 6 Electrode voltage, and then for the scan voltage at the corresponding time "b"-"g" in FIG. 6, these small beams 424b-424g are depicted in FIG. 7. FIG. 8 depicts a direct scan of the ion beam 424 across the workpiece 430, wherein the mechanical actuation (not shown) is during scanning by the scanner 436 in the X direction (e.g., fast scan direction), In that positive Y The workpiece 430 is translated in a direction (eg, a slow scanning direction), whereby the ion beam 424 is applied to the entire exposed surface of the workpiece 430.

Referring again to FIG. 4, one or more deceleration stages 457 are provided downstream of the parallelizing member 439. Examples of deceleration and/or acceleration systems are shown in US Patent Nos. 5,091,655 issued to Dykstra et al., 6,441,382 issued to Huang, and 8,124,946 issued to Farley et al. The entirety of these US patents is hereby incorporated by reference. As previously pointed out, before this point in the system 410, the ion beam 424 is generally transmitted at a relatively high energy level to reduce the tendency of the beam to expand, such as a resolution hole 434 Where the beam density is increased may be particularly high. Similar to the ion extraction assembly 423, scanning element 436, and focusing and guiding element 438, the deceleration stage 457 includes one or more electrodes 457a, 457b operable to decelerate the ion beam 424.

It will be appreciated that although the two electrodes 425a and 425b, 436a and 436b, 438a and 438b, and 457a and 457b are depicted in the example ion extraction component 423, scanning element 436, focusing and guiding element 438, respectively , And deceleration stage 457, but these elements 423, 436, 438, and 457 may include any suitable number of electrodes configured and biased to accelerate and/or decelerate ions, as well as focus, bend, deflect, converge, diverge, The ion beam 424 is scanned, parallelized, and/or cleaned, for example, as proposed in U.S. Patent No. 6,777,696 to Rathmell et al., the entirety of which is incorporated herein by reference. In addition, the focusing and guiding element 438 may include an electrostatic deflection plate (for example, one or more pairs of electrostatic deflection plates), and a single lens (Einzellens), quadrupole, and/or other focusing elements to focus the ion beam. Although not necessary, it may be advantageous to apply a voltage to the deflection plates in element 438 so that they average to zero. The effect is to avoid having to introduce an additional single lens to mitigate the loss of focusing characteristics of element 438 true. It will be appreciated that the “guiding” of the ion beam 424 is a function of the size of the plates 438a, 438b in particular and the guiding voltage applied to it, because the beam direction is proportional to the guiding voltages and the The length of these plates is inversely proportional to the beam energy.

Turning now to FIG. 9, an example deceleration/acceleration stage 457 according to one or more features of the present disclosure is depicted in more detail as an electrode post 500, which includes first and second electrodes 502 and 504 and A pair of middle electrode plates 514 and 516. The first and second electrodes 502 and 504 are substantially parallel to each other, and define first and second holes 506 and 508, respectively. A gap 510 is defined between the holes 506, 508, and the electrodes 502, 504 are configured such that an axis 512 substantially perpendicular to the first and second electrodes 502, 504 extends through the gap 510 And through the first and second holes 506, 508. The middle electrode plates include an electrode 514 in the upper gap and an electrode 516 in the lower gap. A first upper sub-gap region 518 is defined between the first electrode 502 and the electrode 514 in the upper gap. A first lower sub-gap region 520 is defined between the first electrode 502 and the electrode 516 in the lower gap. Similarly, a second upper sub-gap region 522 is defined between the second electrode 504 and the electrode 514 in the upper gap, and a second lower sub-gap region 524 is defined in the second Between the electrode 504 and the electrode 516 in the lower gap. An ion beam 526 passes through the gap 510 and is deflected, for example, about 12 degrees from the axis 512, and is focused at a point 528 downstream of the gap 510.

In the illustrated example, specific bias voltages are depicted to facilitate discussion of the operation of the electrode post 500. However, it will be appreciated that for the purposes of this disclosure, any suitable bias can be applied between the electrodes to achieve the desired result (eg, a degree of acceleration, deceleration, and/or deflection ). Indeed, the variable ion beam energy is In the context of the present disclosure, it will be appreciated that changes in the bias voltage applied to these electrodes will be important. However, the bias value in FIG. 9 is effective to exhibit the deceleration of the ion beam 526.

The ion beam 526 and, more specifically, the positive ion system contained therein passes through the first hole 506 and enters the gap 510 at an initial energy level (for example, 6 KeV in the depicted example). In order to accelerate or decelerate the ions in the beam, the first and second electrodes 502 and 504 are biased differently so that a difference in potential exists between them, and the ions pass through The gap 510 between the first and second electrodes 502, 504 suffers a corresponding increase or decrease in energy. For example, in the example presented in FIG. 9, the positive ion of the ion beam passes from the first electrode 502 with a negative 4KV bias to the second electrode 504 with zero potential (eg, coupled to ground) At the time, suffered a 4KeV energy drop. Therefore, the original positive 6KeV ion beam energy system is reduced to 2KeV when the ions pass through the gap 510, and thus suffers a 4KeV energy drop. Therefore, once the ion beam 526 leaves the gap 510, it will have a specifically generated energy level (eg, 2KeV in the depicted example) and enter a neutral region downstream of the gap 510 530.

It will be appreciated that this is true regardless of the path that ions may take through the gap 510. For example, in the depicted example, ions entering the lower sub-gap 520 between the first electrode 502 and the electrode 516 in the lower gap will be accelerated at a rate greater than entering the first electrode The rate at which the ions in the upper sub-gap 518 between 502 and the electrode 514 in the upper gap will be accelerated. This is because there is a larger potential difference between the first electrode 502 and the electrode 516 in the gap below compared to the difference between the first electrode 502 and the electrode 514 in the gap above Difference (for example, the sub-gap 520 below this is Negative 2.5KV (negative 4KV minus negative 6.5KV), and the upper sub-gap 518 is negative 0.5KV (negative 4KV minus negative 4.5KV).

However, this difference in acceleration is compensated by the corresponding difference in potential between the electrode 514 in the upper gap and the electrode 516 in the lower gap and the second electrode 504. For example, in the depicted example, the second electrode 504 is biased to zero (eg, coupled to ground). Therefore, the ion system from the first lower sub-gap 520 is decelerated to a greater degree than the ions from the first upper sub-gap 518. This compensates for the difference in acceleration of the ions when the ions enter the gap, so that when the ions leave the gap, they all have substantially the same energy (eg, 2KeV). Ions from the sub-gap 520 below the first will be decelerated to a greater degree because when crossing the sub-gap 524 below the second, they will have to traverse the negative 6.5 kV (eg, the lower (The negative 6.5 kV bias of the electrode 516 in the gap minus the zero V bias of the second electrode 504). In contrast, ions from the sub-gap 518 above the first will be decelerated to a lesser degree because when crossing the sub-gap 522 above the second, they will only have to traverse the negative 4.5KV (e.g. , The negative 4.5KV bias of the electrode 614 in the upper gap minus the zero V bias of the second electrode 504). Therefore, regardless of the different paths taken by the ions and the energy level at which they fall, the ions emerging from the effect of the gap are at substantially the same energy level (eg, 2KeV).

It will be appreciated that the electrodes 514, 516 in the upper and lower gaps act to pull the beam into the gap 510 to accelerate or decelerate the ion beam, and are provided for the purpose of beam filtering The dual purpose of beam deflection. For example, the plates 514, 516 in the gap are generally biased differently from each other, so an electrostatic field is developed between them, to bend or deflect the beam either up or down, or according to these The size of the electrode bias and relative to the The energy of the ion beam has a varying magnitude. For example, in the example describing the features, the electrodes 514, 516 in the upper and lower gaps are biased to minus 4.5KV and minus 6.5KV, respectively. Assuming that the beam contains positively charged ions, the difference in potential is such that the positively charged ions passing through the gap 510 are pushed down to the electrode 516 in the more negatively charged gap below, which ultimately The beam 526 is bent or deflected downward (eg, about 12 degrees). It will be appreciated that considering a beam of varying energy, in order to maintain the 12-degree deflection of this example, the bias applied to the electrodes 514, 516 in the gap must also be changed in a corresponding manner.

For example, the acceleration of an ion beam can be initiated by biasing electrodes 534, 536 to negative 4KV, while biasing electrodes 502, 506 to positive 40KV, although any bias value is also considered by this disclosure. This bias configuration creates a negative potential barrier that extends into the neutral region 530. It will be appreciated that under these applied bias voltages, the operation of the device is substantially similar to that described with reference to FIG. 5 except that the beam 526 is accelerated, not decelerated. The values of these examples are to increase the energy level of the beam from, for example, 80KeV to 120KeV, which accelerates the beam by 1.5 times, wherein when the ions traverse the sub-gap region 522 above the second and the second In the lower sub-gap region 524, the positive ions in the beam 526 will be accelerated.

It will be appreciated that the configuration, configuration settings and/or shaping of the electrode 514 in the upper gap and the electrode 516 in the lower gap can be adapted so that the control of the lens effect of the beam becomes easy. For example, in the illustration depicted in FIG. 9, the electrode 516 in the lower gap has a slightly reduced width relative to the width of the electrode 514 in the upper gap, and also has a slightly beveled corner 532 . These adjustments substantially counteract the increased lens effect that the ions of the electrode 516 near the lower gap experience when they undergo strong acceleration and/or deceleration due to differences in applied bias. However, you will realize that For the purpose of this disclosure, these electrodes 514, 516 may have any suitable configuration, including the same shape. It will be further appreciated that the beam can be bent in acceleration, deceleration, and/or drift (eg, zero acceleration/deceleration) modes, because it is mainly responsible for the electrode 514 in the gap above and below the beam bend 516 is substantially independent of the first and second electrodes 502 and 504 which are mainly responsible for the acceleration/deceleration of the beam 510.

The overall net effect of all differences in potential is the focusing, deceleration (or acceleration) and deflection of ions in the beam 526. The deflection of the ion beam provides energy purification because the neutral particles in the beam that are not obstructed by the electrodes continue to follow the original beam path parallel to the axis 512. For example, the contaminants may then encounter some type of barrier or absorption structure (not shown) that prevents the contaminants from traveling forward and shields any workpieces from those contaminants. In contrast, the trajectory of the deflected ion beam 526 is such that the beam properly encounters and doped selected areas of the workpiece (not shown).

It will be appreciated that the configuration of the electrodes (e.g., electrodes 514, 516 in the gap above and below the first and second electrodes 502, 504) also acts to reduce beam expansion Because this configuration minimizes the distance the beam 526 must travel before encountering the wafer. By deflecting the beam 526 (eg, by the electrodes 514, 516 in the upper and lower gaps), while focusing the beam (eg, by the first and second electrodes 502, 504) Instead of having these bending and focusing stages arranged in series, the end station can be located closer to the reducer stage of the ion implantation system.

In the illustrated example, specific bias voltages are depicted to facilitate a better understanding of the operation of the deceleration stage 457 of FIG. However, it will be appreciated that for the purpose of this disclosure, any suitable bias voltage can be applied between the electrodes to achieve The desired result, such as the degree of acceleration, deceleration, and/or deflection. Furthermore, the specific bias voltages are applied in a selectively variable and controlled manner in order to achieve selective and variable energy control of the cost disclosure content. However, the bias value illustrated in FIG. 9 is effective to exhibit the deceleration of the ion beam 526.

It should be noted that the selective change of the bias voltage may, for example, be further based on one or more preset features provided by an operator and one of the descriptions of the workpiece 430 of FIG. 4, and It can be repeated. For example, a "chain implant" may be performed, in which a discrete number of implants with variable doses (eg, a plurality of "chains") are provided to the workpiece 430. For example, each "chain" can be preset by a metrology diagram of the workpiece 430 before implantation. Therefore, the overall effect is a non-uniform variable doping depth profile across the workpiece 430, thus defining the implantation of an energy pattern. For example, chains of different energies can be executed repeatedly, where the dose and doping depth profiles across the workpiece provided in each chain are uniform. Alternatively, topographic feedback can be utilized concurrently with the implant and/or between implanted chains to selectively change the bias voltage.

Turning again to FIG. 4, it will be appreciated that different types of end stations 416 can be used in the implanter 410. For example, a "batch" type terminal station can simultaneously support multiple workpieces 430 on a rotating support structure, where the workpieces 430 are rotated to pass the path of the ion beam until all the workpieces are completely implanted until. On the other hand, a "tandem" type of terminal station supports a single workpiece 430 along the beam path for implantation, where multiple workpieces 430 are implanted one at a time in a tandem manner, where each workpiece 430 is completely implanted before the implantation of the next workpiece 430 starts. In a hybrid system, the work piece 430 can be mechanically translated in a first (Y or slow scan) direction, while the beam is scanned in a second (X or fast scan) direction to shift The ion beam 424 is applied to the entire workpiece 430. In contrast, the so-called two-dimensional mechanical scanning architecture exemplified by an Optima HD ^TM ion implantation system as known in this technology and manufactured and sold by Excellis Technologies of Beverly, Massachusetts The workpiece 430 can be mechanically translated in a first (slow) scanning direction in front of an ion beam at a fixed position, while the workpiece is simultaneously in a second substantially orthogonal (fast) scanning direction It is scanned to apply the ion beam 424 to the entire workpiece 430.

The terminal station 416 in the illustrated example is a "tandem" type terminal station that supports a single workpiece 430 along the beam path for implantation. A dose system 452 is included in the terminal station 416 near the workpiece for calibration measurement prior to the implantation operation. During calibration, the ion beam 424 passes through the dose system 452. The dose system 452 includes one or more analyzers 456 that can continuously traverse an analyzer path 458, thereby measuring the profile of the scanned beam. For example, the analyzer 456 may include a current density sensor, such as a Faraday cup, which measures the current density of the scanned beam, where the current density is the implantation angle (eg, between the beam and the workpiece) The relative orientation between the mechanical surfaces and/or the relative orientation between the beam and the lattice structure of the workpiece) is a function of. The current density sensor moves in a substantially orthogonal manner with respect to the scanned beam, and therefore generally traverses the width of the ribbon beam. In one example, the dose system measures both the beam density distribution and the angle distribution. The measurement of the beam angle can use a moving analyzer which senses the current after a mask with grooves as described in the literature. The displacement of each individual beamlet from the slot position after a short drift can be used to calculate the beamlet angle. It will be appreciated that this displacement can be referred to as a calibrated reference for beam diagnosis in the system.

The dosage system 452 is operatively coupled to a control system 454 to Receive the command signal and provide the measured value to it. For example, a control system 454, which may include a computer, microprocessor, etc., may be operable to take measurements from the dose system 452 and calculate an average angular distribution of the scanned ribbon beam across the workpiece . The control system 454 is also operatively coupled to the terminal 412 from which the ion beam is generated, and the mass analyzer 426 of the beamline assembly 414, the scanning element 436 (eg, via the power supply 449), focusing and Guide element 438 (eg via power supply 450), parallelizer 439 and deceleration/acceleration stage 457. Thus, any of these elements can be adjusted by the control system 454 according to the values provided by the dose system 452 or any other ion beam measurement or monitoring device, so that the desired ion implantation becomes easier . The control signal can also be generated via a look-up table stored in the memory module, which is usually based on empirical data collected through experiments.

For example, the ion beam may initially be established according to preset beam tuning parameters (eg, it is stored/loaded into the control system 454). Then, based on feedback from the dose system 452, for example, the parallelizer 439 can be adjusted to change the energy level of the beam, which can be applied to the ion extraction assembly 423 and the electrodes in the deceleration stage 457 by adjusting The bias voltage is adapted to adjust the junction depth. Accordingly, the intensity and orientation of the magnetic field or electric field generated in the scanner, for example, can be adjusted by adjusting the bias voltage applied to the scan electrodes. The angle of implantation can be further controlled, for example, by adjusting the voltage applied to the guide element 438 or deceleration/acceleration stage 457.

According to a feature of the disclosure, the control system 454 is set up and configured to create a predetermined scan pattern on the workpiece 430, wherein the workpiece is exposed to the spot ion by the control of the scanning system 435 bundle. For example, the control system 454 is configured to control various properties of the ion beam, such as the beam density and current of the ion beam, and others and the The properties related to the ion beam are clearly their energy. Furthermore, the controller 454 is configured to control the scanning speed of the workpiece 430. Most importantly, in the context of the present disclosure for providing a selective variable energy ion beam in an ion implantation system, the control system 454 is configured to modify and adjust the ion implantation applied to the ion implantation system The bias voltage of various subsystems in the system. With respect to the example ion implantation system 410 described above, the control system is configured to modify and change the scanning voltage applied to the scanner 435, and is further configured to modify and change in synchronization with the scanning voltage The bias voltage applied to the deceleration/acceleration stage 457 is used to adjust the energy and deflection of the ion beam accordingly. For example, this modification of the scan voltage and bias voltage is continuous (eg, non-discrete), so it provides various advantages over known systems and methods.

It will be appreciated that the specific purpose of variable energy ion implantation that provides selective control of a workpiece of the present disclosure can be implemented in other ion implantation system architectures known in the art. For example, we can use a so-called ribbon beam architecture to obtain selectively controlled variable energy ion implantation results similar to those described above, one of which has a width that spans the diameter of a wafer. The ion beam system is transferred to a terminal station, which moves the wafer through the ion beam in a one-dimensional scan. A generally known ion implantation system of this nature is manufactured and sold by Varian Semiconductor Equipment Corporation under the trade name VIISta HC. Similarly, we can use a so-called two-dimensional mechanical scanning architecture to obtain ion implantation results similar to those of the selective control variable energy described above, in which a stationary spot ion beam system is delivered To a terminal station, the terminal station moves the wafer through the ion beam in two dimensions. A generally known ion implantation system of this nature is manufactured and sold by Excellis Technology under the trade name Optima HD.

In order to achieve the desired result of cost disclosure in a ribbon beam or two-dimensional mechanical scanning architecture, the system can be used in a manner similar to that in U.S. Patent 4,929,840 (the entire content of this patent is incorporated herein by reference ) Is modified to incorporate wafer rotation control, in which the method and apparatus for controlling the dose of ions implanted in a semiconductor wafer are described. In this patent, the wafer or workpiece is arranged on a platform which is rotated in discrete steps, for example by a stepping motor. After being scanned along an initial path, the dose accumulated by the wafer is measured. When the measured dose of the increment is equal to the total dose to be implanted divided by a preset number of steps in which the implantation is to be performed, the motor steps by an increment. This process is then repeated until the desired total dose is reached.

In a similar manner, the wafer can be transported through a one-dimensional or two-dimensional scanning path through an ion beam having a variable energy as the wafer passes through a stationary ion beam, such as The energy that changes as the wafer passes the beam path from top to bottom. For example, the beam can be provided with a low energy at the beginning of the wafer scan, and as the center of the wafer moves toward the stationary beam and an initial ion dose is accumulated by the wafer Increasing from time to time (eg, continuously). When the measured dose of the increment is equal to the total dose to be implanted divided by a preset number of steps in which the implantation is to be performed, the motor steps by an increment. This process is then repeated until the desired total dose is reached. By maintaining the same variable energy profile for each step increment, a variable energy ion implant can be achieved on the wafer.

Therefore, in a ribbon beam or a two-dimensional point beam, a discrete step is passed around a shaft (which is perpendicular to and intersecting on the wafer) via a stepping motor 470 such as FIG. 4. The axis of the surface of a wafer on the wafer coincides) to rotate the wafer support can be utilized to selectively Change the energy profile of ion implantation of the wafer. For example, such a method includes a control system configured to obtain a dose information signal, and in response to the dose information signal, send a signal to provide stepped rotation of the support device. In order to meet the above requirements, the ion implanter provides, for example, a function to rotate the wafer during implantation or between implantation, and provides a control for the above type of ion implantation system architecture. Wafer rotation system.

In order to meet the above objectives, the present disclosure may include a stepping motor 470 to rotate the receiving wafer platform around the wafer axis, and a system for controlling the stepping motor, whereby the wafer is provided with some It can be rotated in discrete steps (or continuously) on the order of 0 to 90 degrees. Therefore, by performing multiple rotations and changing the energy as a function of the slow scanning direction of the wafer, the energy can be changed from the top edge to the center and back to the bottom edge. In one example, it will be understood that the dose will be accumulated in 1/n increments, where n is the number of discrete rotations. For example, each step is related to being controlled by the beam current measured by a Faraday cup so as to provide a uniform dose distribution as a function of angular rotation. The rotary drive system preferably includes a stepper motor operable to rotate the platform assembly about an axis perpendicular to the wafer surface and through its center. In operation, the required total dose and the required number of rotations of the platform assembly are entered into a stepper motor controller, where the required dose is divided by the total number of implanted steps to determine each motor step The dose to be implanted.

As the implantation proceeds, the accumulated ion dose is collected by a Faraday cup, which provides a beam current signal to the controller indicating the accumulated dose. When the cumulative accumulated dose is equal to the calculated dose for each step, a signal is sent to the stepper motor to rotate the wafer one step. The implantation is performed in this way until the accumulated dose, etc. Up to the desired total dose, at this point in time, the implantation will be completed, and the beam will be gated "off" by a signal to a gate controller.

It will also be understood that the present disclosure can be combined with features known in the art to provide even greater variability in the ion implantation process during ion implantation. For example, as previously indicated, there are some disclosures in the prior art regarding the features of providing variable dose control for implantation. The features of the present disclosure for providing selective variable energy control of an implantation process can be combined with these features for providing selective variable dose control of an ion implantation process to achieve cross-over Selective variable energy and dose ion implantation on the surface of the wafer.

According to the present disclosure, the system described herein enables a method for implanting ions at varying depths, as depicted in the form of the flowchart of FIG. 10. It should be noted that although the example method is depicted and described here as a series of actions or events, it will be appreciated that the content of this disclosure is not limited to the order in which such actions or events are illustrated Because, according to the present disclosure, some steps may occur in a different order and/or simultaneously with other steps than those shown and described herein. Furthermore, not all illustrated steps may be required to implement a method according to the present disclosure. Furthermore, it will be appreciated that these methods can be implemented in relation to the systems depicted and described herein and other systems not depicted.

The method 600 of FIG. 10 begins at act 602 by placing a workpiece on a support. In act 604, an ion beam system such as a spot ion beam is provided, and in act 606, the ion beam system is mass analyzed. In act 608, one or more of the workpiece and the ion beam are scanned relative to each other. For example, the workpiece is in action 608 It is scanned mechanically in the orthogonal direction. In another alternative, the ion beam is electrostatically or magnetically scanned in a first direction and mechanically scanned in a second direction. In yet another alternative, the ion beam system is electrostatically scanned in two non-parallel directions.

In act 610, an energy system of the ion beam is selectively changed in a continuous manner simultaneously with the scan of act 608. Thus, the depth of ion implantation into one of the workpieces is changed along a surface of the workpiece.

Therefore, the present disclosure is directed to an ion implantation system and method for changing the energy of an ion beam as it travels across a workpiece, or vice versa. The content of this disclosure is enabled by changing the bias voltage applied to the acceleration/deceleration electrode, so that the ion energy transferred to a workpiece can be selectively changed to achieve a predetermined variable energy in the workpiece pattern. In a preferred embodiment, the present disclosure will respond to a pair of mappings across the workpiece and the mapping becomes a continuous function of the matrix to provide a continuously variable energy pattern that can be used to program the radiation The energy of the beam is a function of the position across the workpiece. For example, the present disclosure can be implemented by generating a spatial mapping in memory, where each cell of the memory location corresponds to a unique energy associated with one of the x and y locations on the workpiece. It will be appreciated that the present disclosure can be incorporated into a system for providing a continuously variable energy, a step function change in energy, or other forms of variable energy implantation. The change in the energy profile across the surface of the workpiece may be symmetrical, and may also be presented in quadrants or other ways, for example, X ₁ energy at a designated position Q ₁ , X ₂ energy at Q ₂ , So on and so forth.

The example ion implantation system architecture described herein for illustrative purposes is particularly suitable for enabling selective changes in ion beam energy across the surface of a workpiece, where the system 410 of FIG. 4 incorporates a scan Point beam, where the beam is electronic or magnetic Trace across the surface of the workpiece. Such scanning of a one-point beam allows modulation of the energy of the ion beam as the selectivity of the scanning of the beam changes. Therefore, when the beam is scanned to strike a selected position on the wafer, it passes through all the optical elements of the beam line, where the beam can be modified to change its energy before hitting the wafer One selected energy. Advantageously, the change in the beam energy can be achieved synchronously with the x and y scanning functions of the scanner and/or terminal station, so that the energy of the scanned beam can be used as a function of x and y To change. In addition, the bias voltage applied to the deceleration/acceleration and its deflection energy filter characteristics can be selectively changed as a function of the x and y positions of the scanned beam, so that the beam can be limited to the same Path travels to the wafer regardless of the energy change of the ion beam.

It will be appreciated that all selective biases of components and subsystems can be achieved via the control system 454 and can be input to the acceleration via a feedback loop based on the beam position output from the scanning system / Deceleration stage and this energy filter are implemented. However, it will be understood that a feedback loop is not one of the requirements for the selectively variable energy ion implantation feature used to enable this disclosure, as a pre-programmed ion beam energy profile can also be beneficial Is implemented to perform the selective variable energy ion implantation of the present disclosure. In this connection, the energy of the ion beam can be through a feedback loop for the x,y coordinate position of the beam on the wafer, or through a predetermined desired pattern, per die, or It is some other feature or area to be selectively changed.

The selectively variable energy ion implantation of the present disclosure can also be implemented through a mapping of the workpiece, which is supplied to one of one or more of the electrodes of the electrode column and/or the energy filter, respectively The selective change of the voltage or voltages depends on a mapping of a workpiece provided on the workpiece support. In another alternative, the ion implant of the present disclosure The entry system may be provided with a detector or a plurality of detectors, which are configured to detect one or more properties of a workpiece provided on the workpiece support, which are respectively supplied to the deceleration/acceleration stage The selective change of one or more voltages of the electrode column and/or one or more of the energy filters is further determined based on the feedback from the detector. According to this alternative embodiment, the one or more detectors may preferably be configured to detect a thickness of the workpiece, a thickness of a layer disposed on the workpiece, and a crystal on the workpiece One or more of a grain pattern, an edge of the workpiece, a center of the workpiece, or a predefined area on the workpiece, where the detected information is provided as input to selectively Change the energy of the ion beam.

Although the present invention has been described and described in relation to one or more embodiments, it will be understood that changes and/or modifications can be made to the illustrated examples without departing from the scope of the attached patent application Spirit and scope. In particular, the various functions performed by the above-mentioned components or structures (blocks, units, engines, components, devices, circuits, systems, etc.) are used to describe such components unless otherwise indicated These terms (including any reference to "device") are intended to correspond to any component or structure that performs the specified function of the described component (eg, it is functionally equivalent), even if it is not structurally equivalent It is equivalent to the structure disclosed in the exemplary embodiment of the present invention described herein to perform the function. In addition, although a particular feature of the present invention may have been disclosed in relation to only one of the several embodiments, such feature is as long as it may be desired and advantageous for any given or specific application Both can be combined with one or more other features of other embodiments. Furthermore, under the scope that the terms "including", "having", "with", or variations thereof are used in the detailed description and patent application, such terms are intended to be similar to the The term "comprising" is inclusive.

410‧‧‧Ion implantation system

412‧‧‧Terminal

414‧‧‧Bundle assembly

416‧‧‧Terminal

418‧‧‧ slit

420‧‧‧Ion source

421‧‧‧ Production room

422‧‧‧Power supply

423‧‧‧Ion extraction module

424‧‧‧Ion beam

424a‧‧‧small beam

425a、425b‧‧‧electrode

426‧‧‧Quality Analyzer

427‧‧‧Sidewall

430‧‧‧Workpiece

432‧‧‧beam guide

434‧‧‧Analysis hole

435‧‧‧ Scanning system

436‧‧‧scanning element

436a、436b‧‧‧electrode

437‧‧‧ distance traveled

438‧‧‧focus/guide element/parallelizer

438a, 438b ‧‧‧ electrode

439‧‧‧Parallelizer

439a, 439b ‧‧‧ bipolar magnet

441‧‧‧ scanning vertex

449‧‧‧Power supply

450‧‧‧Power supply

452‧‧‧Dose system

454‧‧‧Control system

456‧‧‧Analyzer

457‧‧‧Acceleration or deceleration/filtration subsystem

457a、457b‧‧‧electrode

458‧‧‧Analyzer path

470‧‧‧stepping motor

Claims (24)

An ion implantation system configured to provide a selectively variable energy ion beam to a workpiece includes: an ion source configured to ionize a dopant material for generating an ion beam A mass analyzer disposed downstream of the ion source, which is configured to provide a mass analyzed ion beam; a deceleration/acceleration stage disposed downstream of the mass analyzer, which is configured to receive the Mass-analyze the ion beam to generate the selectively variable energy ion beam; a terminal station downstream of the deceleration/acceleration stage, wherein the terminal station includes a workpiece support, the workpiece support is configured to Selectively placing the workpiece in front of the selectively variable energy ion beam for ion implantation thereby; a scanning device configured to scan the ion beam and the workpiece support relative to each other One or more of; one or more power supplies operably coupled to one or more of the ion source, mass analyzer, and deceleration/acceleration stage; and a control system coupled to the One or more power sources and configured to selectively change at least one bias voltage supplied to the deceleration/acceleration stage simultaneously with the scanning of the ion beam and/or workpiece support, wherein the at least one is supplied to the The selective change of the bias voltage of the deceleration/acceleration stage is based at least in part on a position of the ion beam relative to the workpiece to provide a selectively variable energy ion beam to the workpiece. For example, the ion implantation system of patent application scope item 1, which further includes: an energy filter for deflecting ions with a desired energy to define a An ion beam of desired energy is delivered to the terminal station; wherein the control system is further configured to selectively change one or more of the ion beam and/or the workpiece support simultaneously while scanning one or more of them to be supplied to The voltage of the energy filter is such that the selective change of the one or more voltages depends at least in part on the energy of the ion beam. An ion implantation system as claimed in item 1 of the patent application, wherein the selective change of the at least one bias voltage is synchronized with the selective scanning of the ion beam and/or the workpiece support being guided to be set An energy of the ion beam of the workpiece on the workpiece support. For example, in the ion implantation system of claim 3, the selective change of the at least one bias voltage depends on a position of the ion beam along a scanning path. An ion implantation system as claimed in item 3 of the patent application, wherein the selective change of the at least one bias voltage is further based on one or more pre-provisions provided by an operator and one of a description of the workpiece Set characteristics. An ion implantation system as claimed in item 1 of the patent application, wherein the scanning device includes an electrostatic and/or magnetic scanner configured to be electrostatically and/or magnetically respectively along at least a first scanning axis Scan the ion beam. An ion implantation system as claimed in claim 6, wherein the scanning device further includes a mechanical scanning system configured to mechanically scan the workpiece along a second scanning axis that is not parallel to the first scanning axis supporting item. For example, in the ion implantation system of claim 7, the first scanning axis is orthogonal to the second scanning axis. An ion implantation system as claimed in item 1 of the patent application, wherein the scanning device includes a mechanical scanning system configured to be along a first scanning axis and a substantially orthogonal to the first scanning Both the second scanning axis of the scanning axis mechanically scans the workpiece support. As in the ion implantation system of claim 1, the selective change of the one or more voltages respectively supplied to the deceleration/acceleration stage is based on the indication from the scanning system of the ion beam relative to the workpiece The location depends on the feedback. An ion implantation system as claimed in item 2 of the patent application, wherein the selective change of the one or more voltages respectively supplied to the energy filter is based on the position from the scanning system indicating the position of the ion beam relative to the workpiece It depends on the feedback. As in the ion implantation system of claim 1, the selective change of the at least one bias voltage respectively supplied to the deceleration/acceleration stage is preset. As in the ion implantation system of claim 2, the selective change of the one or more voltages respectively supplied to the energy filter is preset. An ion implantation system as claimed in item 1 of the patent application, wherein the selective change of the voltages supplied to the one or more of the deceleration/acceleration stage and the energy filter is based on a The mapping of the workpieces set on the workpiece support depends on the mapping. An ion implantation system as claimed in item 14 of the patent application, wherein the mapping of the workpiece includes a mapping of a material layer thickness across a surface of the workpiece. An ion implantation system as claimed in item 1 of the patent application, wherein the selective change of the one or more voltages supplied to the deceleration/acceleration stage and the energy filter is further based at least in part on one or more and one The position of the workpiece-related features provided on the workpiece support. For example, the ion implantation system of claim 15, wherein the one or more features include a layer formed on the workpiece, a grain pattern on the workpiece, an edge of the workpiece, One or more of a center of the workpiece and a predefined area on the workpiece. For example, the ion implantation system of claim 1, wherein the deceleration/acceleration stage includes one or more of an ion beam accelerator and an ion beam reducer. The ion implantation system as claimed in item 1 of the patent application further includes a detector configured to detect one or more properties of a workpiece disposed on the workpiece support, and wherein The selective change of the one or more voltages supplied to the deceleration/acceleration stage and one or more of the energy filters, respectively, is further dependent on the feedback from the detector. An ion implantation system as claimed in claim 19, wherein the detector is configured to detect a thickness of the workpiece, a thickness of a layer disposed on the workpiece, and a crystal on the workpiece One or more of a grain pattern, an edge of the workpiece, a center of the workpiece, and a predefined area on the workpiece. An ion implantation system as claimed in item 1 of the patent application, wherein the workpiece support includes: a motor configured to rotate the support around an axis in discrete steps, the axis being perpendicular to and intersecting with an axis The axis of the surface of the workpiece accommodated on the workpiece support is consistent, wherein the control system is configured to control the motor; and a dose amount for measuring a dose of ions implanted in the workpiece Measuring device, wherein the control system is operable to receive a dose information signal from the dose measuring device and send a control signal to the motor for further providing step rotation of the workpiece support. For example, the ion implantation system of claim 21, wherein the motor includes a stepping motor. As for the ion implantation system of claim 1, the at least one of which is supplied to the The selective change of the bias voltage of the deceleration/acceleration stage is iterative, thus defining a chain implant, and further based at least in part on one or more provided by an operator and one of a description of the workpiece Depending on a preset feature. As in the ion implantation system of claim 1, the selective change of the at least one bias voltage supplied to the deceleration/acceleration stage is substantially continuous.

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