JP5151633B2 - Pattern forming method, pattern forming apparatus, and device manufacturing method - Google Patents

Description

  The present invention relates to a pattern forming method, a pattern forming apparatus, and a device manufacturing method, and more specifically, a pattern forming method and a pattern forming apparatus that can be suitably used in a lithography process for manufacturing a micro device such as a semiconductor element, and the like. The present invention relates to a device manufacturing method using the pattern forming method.

  Conventionally, in a lithography process for manufacturing electronic devices (microdevices) such as semiconductor elements (integrated circuits, etc.), liquid crystal display elements, etc., a step-and-repeat type projection exposure apparatus (so-called stepper) or a step-and-scan type Projection exposure apparatuses (so-called scanning steppers (also called scanners)) are mainly used.

  In order to achieve a high throughput in this type of exposure apparatus, a plurality of, for example, two stages (wafer stages) for holding an object to be exposed (hereinafter referred to as a wafer) such as a wafer or a glass plate are provided. There has been proposed a twin-stage type exposure apparatus that processes two different operations in parallel using a wafer stage (see, for example, Patent Document 1).

  In a twin stage type exposure apparatus, the position control accuracy and / or control characteristics may differ from wafer stage to wafer stage even though each wafer stage is driven and controlled using a common position measurement system and drive system. is there. For this reason, when two or more wafer stages are used together to form a plurality of layers of circuit patterns on the wafer, there is a possibility that a misalignment (overlay error) of a non-negligible level between the circuit patterns between the layers may occur.

US Pat. No. 7,161,659

The present invention has been made under the circumstances described above. From a first viewpoint, the present invention is a pattern forming method for forming a plurality of patterns on an object using a plurality of stages, which is recorded on the object. Based on the information that reads the information and indicates the previous exposure process for the object included in the information , the stage used when forming the previous pattern on the object and the stage that is scheduled to be used next matching a step of determining whether: the object the information is read, the next use is mounted on the stage, which is scheduled process and; from the step of the determining the determination result, the destination If the stage used when forming the pattern does not match the stage scheduled to be used next, the next pattern is synchronized with the stage scheduled to be used next and the stage. When forming the previous pattern by calibrating one position control characteristic of the mask stage holding and moving the mask formed with the position control characteristic of the stage used in forming the previous pattern If the stage used for the second stage coincides with the stage scheduled to be used next, the position control characteristic is not calibrated and the next pattern is superimposed on the previous pattern on the object. Forming a first pattern forming method.

  According to this, whether the stage used for reading the information recorded on the object and forming the previous pattern on the object matches the stage that is scheduled to be used next is based on the information. Judge whether or not. Then, in consideration of the determination result, the next pattern is formed on the object so as to be superimposed on the previous pattern.

  In this case, the object is placed on the stage that is scheduled to be used next, regardless of whether the stage that is scheduled to be used next matches the stage that was used to form the previous pattern. It is also possible to place the object on the stage used for forming the previous pattern on the object.

  In any case, depending on whether the stage used to form the previous pattern is the same as or different from the stage actually used, it is possible to know in advance the relationship between the characteristics of the alignment of both stages. I can do it. Therefore, when the next pattern is aligned with the previous pattern and formed on the object, the relationship can be taken into consideration, so that highly accurate superposition can be performed.

According to a second aspect of the present invention, there is provided a pattern forming method for forming a plurality of patterns on an object using a plurality of stages, wherein information recorded on the object is read, and the object is read based on the information. A step of determining whether or not the stage used when the previous pattern is formed and the stage scheduled to be used next are the same; in consideration of the determination result of the determining step; A step of forming a next pattern on the object by superimposing the previous pattern; and a stage where only the object determined to be placed based on the determination result of the determination step is scheduled to be used next And a second pattern forming method .
According to a third aspect of the present invention, a step of forming a pattern on an object using any one of the first and second pattern forming methods of the present invention; and a step of processing the object on which the pattern has been formed And a device manufacturing method.

According to a fourth aspect of the present invention, there is provided a pattern forming apparatus for forming a plurality of patterns on an object, the plurality of stages holding the object and movable within a predetermined region; A driving system for driving a stage; a pattern generating device for generating the plurality of patterns on the object; a reading device for reading information recorded on the object; and a previous device for the object included in the read information based on the information indicating the exposure step, a stage that is used in forming the previous pattern on the object, then a determination device and the stage of use is expected to determine whether they match; the the information is read object, a conveying apparatus used in the following are mounted on the stage being scheduled; superimposed on the destination of the pattern on the object during the formation of the next pattern From the determination result of the determination device, when the stage used in the following a stage that was used to form the destination pattern is scheduled does not match, stages used in the following to be expected The position control characteristic of one of the mask stage that holds and moves the mask on which the next pattern is formed in synchronization with the stage is calibrated to the position control characteristic of the stage used when forming the previous pattern. If the stage used for forming the previous pattern matches the stage scheduled to be used next, the position control characteristic is not calibrated and the control for controlling the drive system is performed. system and; a first pattern forming apparatus provided with.

  According to this, the information recorded on the object is read by the reading device, and based on the information read by the determination device, the stage used for forming the previous pattern on the object and the next use is scheduled. It is determined whether or not the stage being matched matches. When the control system forms the next pattern by superimposing the previous pattern on the object, at least one of the drive system and the pattern generation device is controlled according to the determination result of the determination device.

In this case, based on the determination result of the determination device, the characteristics of the alignment of the stage used when forming the previous pattern and the stage actually used (or the stage scheduled to be used next) are adjusted. You can know the relationship in advance. Accordingly, in order to adjust the relative position between the pattern and the stage when the next pattern is aligned with the previous pattern and formed on the object, the control system considers the relationship and By controlling at least one of the pattern generation devices, high-precision superposition is possible.
According to a fifth aspect of the present invention, there is provided a pattern forming apparatus for forming a plurality of patterns on an object, the plurality of stages holding the object and movable within a predetermined area; A driving system that drives a stage; a pattern generation device that generates the plurality of patterns on the object; a reading device that reads information recorded on the object; and on the object based on the read information, A determination device for determining whether or not the stage used when forming the pattern is coincident with the stage scheduled to be used next; and overlaying the previous pattern on the object A control system that controls at least one of the drive system and the pattern generation device according to a determination result of the determination device when forming a pattern; Only the object result determined, conveying device and that used in the following are mounted on the stage being scheduled; a second pattern forming apparatus provided with.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 schematically shows a configuration of a twin stage type exposure apparatus 100 according to an embodiment. The exposure apparatus 100 is a step-and-scan projection exposure apparatus, a so-called scanner. As will be described later, in the present embodiment, the projection optical system PL and the alignment system ALG are provided. In the following, the direction parallel to the optical axis AX of the projection optical system PL is the Z-axis direction, and the plane perpendicular to the Z-axis direction. The direction parallel to the straight line connecting the center of the projection optical system PL (optical axis AX) and the detection center of the alignment system ALG (optical axis AXp) is the Y-axis direction, and the direction perpendicular to the Z-axis and Y-axis is the X-axis direction. The rotation (inclination) directions around the X, Y, and Z axes will be described as the θx direction, the θy direction, and the θz direction, respectively.

  The exposure apparatus 100 includes an illumination system 10, a reticle stage RST, a projection unit PU, an alignment system ALG, a stage apparatus 50, and a control system thereof. The exposure apparatus 100 also includes a writing device LM, a reading device LR (not shown in FIG. 1, see FIG. 4), and a transport system 28 (not shown in FIG. 1, see FIG. 4). In FIG. 1, the two wafer stages WST1 and WST2 constituting the stage apparatus 50 are positioned below the projection unit PU and below the alignment system ALG, respectively. Wafers W1 and W2 are mounted on wafer stages WST1 and WST2, respectively.

  As disclosed in, for example, US Patent Application Publication No. 2003/0025890, the illumination system 10 includes a light source, an illumination uniformizing optical system including an optical integrator, an illumination optical system including a reticle blind, and the like (both (Not shown). The illumination system 10 illuminates the slit-shaped illumination area IAR on the reticle R defined by the reticle blind (masking system) with illumination light (exposure light) IL with a substantially uniform illuminance. Here, for example, ArF excimer laser light (wavelength 193 nm) is used as the illumination light IL.

  On reticle stage RST, reticle R on which a circuit pattern or the like is formed on its pattern surface (the lower surface in FIG. 1) is fixed, for example, by vacuum suction. The reticle stage RST can be finely driven in the XY plane by a reticle stage drive system 11 (not shown in FIG. 1, refer to FIG. 4) including, for example, a linear motor and the like, and in the scanning direction (left and right direction in FIG. 1). In the Y-axis direction) at a predetermined scanning speed.

  Position information of the reticle stage RST in the XY plane (including rotation information in the θz direction) is transferred by a reticle laser interferometer (hereinafter referred to as a reticle interferometer) 116 to a movable mirror 15 (actually orthogonal to the Y-axis direction). Are always detected with a resolution of about 0.25 nm, for example, via a Y moving mirror (or retroreflector) having a reflecting surface and an X moving mirror having a reflecting surface perpendicular to the X-axis direction). . Position information from reticle interferometer 116 is sent to main controller 20 (not shown in FIG. 1, see FIG. 4). Main controller 20 controls the position (and speed) of reticle stage RST via reticle stage drive system 11 based on the position information.

  Projection unit PU is arranged below reticle stage RST in FIG. 1 (in the −Z direction), and is held by a main frame (not shown). The projection unit PU includes a lens barrel 40 and a projection optical system PL held in the lens barrel 40. As projection optical system PL, for example, a refractive optical system including a plurality of optical elements (lens elements) arranged along optical axis AX parallel to the Z-axis direction is used. The projection optical system PL is, for example, both-side telecentric and has a predetermined projection magnification (for example, 1/4 times, 1/5 times, or 1/8 times). For this reason, when the illumination area IAR on the reticle R is illuminated by the illumination system 10, the illumination light that has passed through the reticle R arranged so that the first surface (object surface) and the pattern surface of the projection optical system PL substantially coincide with each other. The reduced image of the circuit pattern of the reticle R in the illumination area IAR (a reduced image of a part of the circuit pattern) is passed through the projection optical system PL (projection unit PU) by the IL on the second surface (image surface) side. Is formed in a region (hereinafter also referred to as an exposure region) IA that is conjugate to the illumination region IAR on the wafer W1 (or W2) having a resist (sensitive agent) coated on the surface thereof. Then, by synchronous driving of reticle stage RST and wafer stage WST1 (or WST2), reticle R is moved relative to illumination area IAR (illumination light IL) in the scanning direction (Y-axis direction) and exposure area IA ( By scanning the wafer W1 (or W2) relative to the illumination light IL) in the scanning direction (Y-axis direction), scanning exposure of one shot area (partition area) on the wafer W1 (or W2) is performed. The reticle pattern is transferred to the shot area. That is, in the present embodiment, a pattern is generated on the wafer W1 (or W2) by the illumination system 10, the reticle R, and the projection optical system PL, and the sensitive layer (resist layer) on the wafer W1 (or W2) by the illumination light IL. The pattern is formed on the wafer W1 (or W2) by exposure.

  The alignment system ALG is disposed at a position spaced a predetermined distance on the −Y side from the center of the projection unit PU (the optical axis AX of the projection optical system PL (which also coincides with the center of the exposure area IA in the present embodiment)), It is held by a main frame (not shown). Here, as the alignment system ALG, for example, an image processing type FIA (Field Image Alignment) system is used. Alignment system ALG performs a reference mark on wafer stage WST1 or WST2 or an alignment mark (wafer mark) on wafer according to an instruction from main controller 20 during wafer alignment (for example, enhanced global alignment (EGA)). The image signal is supplied to the main controller 20 via a signal processing system (not shown) (see FIG. 4).

  As shown in FIG. 1, stage device 50 includes a measurement system 200 including wafer stages WST1 and WST2 disposed above base board 12, and interferometer system 118 for measuring position information of both stages WST1 and WST2. (See FIG. 4) and a stage drive system 124 (see FIG. 4) for driving both stages WST1 and WST2. Wafer stages WST1 and WST2 are levitated and supported above base board 12 through a clearance of about several μm by an air slider which will be described later. Each of the stage driving systems 124 can be driven in the XY plane along the upper surface (moving guide surface) of the base board 12 by a planar motor, which will be described later.

  Wafer stage WST1 includes a stage main body 91 and wafer table WTB1 mounted on stage main body 91, as shown in FIG. The stage body 91 is integrally provided around the lower half of the movable element 56 and the movable element 56 constituting the planar motor 51, together with the stator 52 embedded in the base board 12, and includes a plurality of air bearings. And an air slider 54.

  The mover 56 is constituted by a magnet unit including a flat plate-shaped magnet generator composed of a plurality of flat magnets arranged in a matrix so that the polarities of adjacent magnetic pole faces are different from each other, for example.

  On the other hand, the stator 52 is constituted by an armature unit having a plurality of armature coils (drive coils) 57 arranged in a matrix in the base board 12. As the armature coil 57, in this embodiment, an X drive coil and a Y drive coil are provided. Then, a moving magnet type of electromagnetic force driving method (Lorentz force driving method) is constituted by a stator 52 composed of an armature unit including a plurality of X driving coils and Y driving coils and a mover 56 composed of the above-mentioned magnet unit. A planar motor 51 is configured.

  The armature coil 57 is covered by a flat plate member 58. The flat plate member 58 constitutes the upper surface of the base board 12, and the upper surface constitutes a pressure guide surface for the pressurized air from the air bearing provided in the air slider 54 and the movement guide surface of the wafer stage WST.

  Wafer table WTB1 is mounted on stage main body 91 via a Z / leveling mechanism (not shown) (for example, including a voice coil motor). Wafer table WTB1 is finely driven in the Z-axis direction, θx direction, and θy direction with respect to stage main body 91 by the Z-leveling mechanism. Therefore, wafer table WTB is driven in a direction of six degrees of freedom (X, Y, Z, θx,...) Relative to base board 12 by a drive system (part of stage drive system 124) including planar motor 51 and Z / leveling mechanism. It can be driven to θy, θz).

  As shown in FIG. 1, a wafer holder WH for holding the wafer (W1) by vacuum suction or the like is provided on the upper surface of wafer table WTB1. As shown in FIG. 2 (B), wafer holder WH is arranged at the center of wafer table WTB1 (however, in FIG. 2 (B), it is hidden behind the paper surface of wafer W1). It has been.

  Further, a reference mark plate FM is fixed at the center in the X-axis direction near the + Y side end on the upper surface of wafer table WTB1. The surface of the reference mark plate FM is substantially flush with the surface of the wafer W1. On the surface of the reference mark plate FM, at least a pair of first reference marks detected by a reticle alignment detection system described later and a second reference mark detected by the alignment system ALG are formed.

  On the −X side end surface, + Y side end surface, + X side end surface, and −Y side end surface of wafer table WTB1, as shown in FIG. 2B, reflecting surfaces 27a, 27b, 27c and 27d are formed.

  Wafer stage WST2 is configured similarly to wafer stage WST1.

  As shown in FIG. 3, the interferometer system 118 includes four Y interferometers 16, 17, 18, and 19 and four X interferometers 116, 117, 126, and 127. The Y interferometers 16, 17, and 18 are arranged on the + Y side of the base board 12 at different positions with respect to the X-axis direction. The Y interferometer 19 is disposed on the −Y side of the moving surface of the base board 12 so as to face the Y interferometer 17. The X interferometers 116 and 117 are arranged on the −X side of the base board 12 at a predetermined interval in the Y-axis direction. The X interferometers 126 and 127 are disposed on the + X side of the base board 12 so as to face the X interferometers 116 and 127, respectively.

The Y interferometer 17 includes three length measuring beams B17 ₁ parallel to the Y axis along a straight line (reference axis) LV ₀ parallel to the Y axis connecting the optical axis AX of the projection optical system PL and the detection center of the alignment system ALG. , B17 ₂ , and B17 ₃ are projected onto the reflecting surface 27b of the wafer table WTB1 (or WTB2), each reflected light is received, and the displacement in the Y-axis direction of the reflecting surface 27b at each measurement beam irradiation point is changed. measure. The length measuring beams B17 ₁ and B17 ₂ pass through an optical path that is spaced apart from the reference axis LV ₀ by an equal distance in the ± X direction, and the length measuring beam B17 ₃ passes through an optical path that is separated by a predetermined distance from these optical paths. The measurement value of the Y interferometer 17 is supplied to the main controller 20.

The main controller 20, based on the average value of the measurement beams _B17 1, B17 ₂ measurements by, calculates the position in the Y-axis direction of wafer table WTBl (or WTB2) a (Y position). That is, the substantial measurement axis in the Y-axis direction of Y interferometer 17 coincides with the reference axis LV _0. The main control unit 20, based on the difference between the measurement values by measurement beams _B17 1, B17 _2, and calculates the θz direction of rotation information of wafer table WTBl (or WTB2) (yawing amount). Further, main controller 20, measurement beams _B17 1, B17 one measurement value by _two (or average value of both measurement values) and measurement beam B17 ₃ wafer table WTB1 based on a difference between the measured value by ( Alternatively, rotation information (pitching amount) in the θx direction of WTB2) is calculated.

Y interferometers 16, 18, and 19 are used to measure the Y position, pitching amount, and yawing amount of wafer table WTB 1 (or WTB 2), similarly to Y interferometer 17. Y interferometers 16 and 18 have measurement axes LV ₁ and LV ₂ that are parallel to reference axis LV ₀ , respectively. Further, the Y interferometer 19 has a substantial length measurement axis as a reference axis LV ₀ and three length measurement beams B19 ₁ , B19 ₂ , B19 ₃ on the reflection surface 27d of the wafer table WTB1 (or WTB2). Project.

The X interferometer 116 converts _two length measuring beams B116 ₁ and B116 ₂ separated in the Z-axis direction along the optical axis AX of the projection optical system PL and the reference axis LH orthogonal to the reference axis LV ₀ into the wafer table WTB1. (Or WTB2) is projected onto the reflecting surface 27a, receives the respective reflected light, and measures the displacement in the X-axis direction of the reflecting surface 27a at the irradiation point of each length measuring beam.

Similarly, the X interferometer 126 projects two measurement beams B126 ₁ and B126 ₂ that are separated in the Z-axis direction along the measurement axis LH onto the reflection surface 27c of the wafer table WTB1 (or WTB2), respectively. Is received, and the displacement in the X-axis direction of the reflecting surface 27 at the irradiation point of each length measuring beam is measured. The measurement values of the X interferometers 116 and 126 are supplied to the main controller 20.

Main controller 20 calculates the X position of wafer table WTB1 (or WTB2) based on the measurement value of at least one of length measurement beams B116 ₁ and B126 ₁ . The main control unit 20, the difference in measurement beams B116 _1, B116 ₂ measurements by, or on the basis of the difference between the measurement beam B 126 _1, B 126 ₂ measurements by, rolling amount of wafer table WTBl (or WTB2) (θy) is calculated.

The X interferometers 117 and 127 are used to measure the X position and the θy direction position (rolling amount) of the wafer table WTB1 (WTB2), similarly to the X interferometers 116 and 126. The measurement method is the same as the measurement using the X interferometers 116 and 126 except that the reference axis LA parallel to the X axis orthogonal to the reference axis LV _{0 at} the detection center of the alignment system ALG is the measurement axis.

  Thus, by using the interferometer system 118 including the Y interferometers 16, 17, 18, and 19 and the X interferometers 116, 117, 126, and 127, five degrees of freedom (X, W) of the wafer table WTB1 (or WTB2). Y, θx, θy, θz) position information can be measured.

  In addition to the above-described X and Y interferometers, the interferometer system 118 projects a length measuring beam along the X axis onto a first reflecting surface provided at an angle of 45 degrees on the wafer stages WST1 and WST2. A Z interferometer for measuring the positions of wafer stages WST1 and WST2 in the Z-axis direction and the θy direction by receiving reflected light from the second reflecting surface provided on the lower surface of the frame through the first reflecting surface. Also included.

  In the present embodiment, in order to measure the position information of wafer table WTB1 (or WTB2) in the XY plane, encoder system 150 that constitutes measurement system 200 together with interferometer system 118, in addition to interferometer system 118 described above. (See FIG. 4) is provided. Therefore, the position of wafer table WTB1 (or WTB2) is measured mainly using interferometer system 118, and encoder system 150 causes wafer stage WST1 (or WST2) to be outside the measurement region of interferometer system 118, as will be described later. It shall be used when positioned. Of course, interferometer system 118 and encoder system 150 may be used together to measure the position of wafer table WTB1 (or WTB2) in the XY plane.

  As shown in FIG. 1, the writing device LM is disposed at a position spaced apart from the alignment system ALG by a predetermined interval, and is held by the main frame. The writing device LM is a device for writing various information necessary for managing the wafer in the exposure process onto the wafer W (wafer W2 in FIG. 1). The writing device LM includes, for example, a light source that emits light having the same wavelength as the illumination light IL, and projects the light onto an area other than the shot area of the wafer W to expose the sensitive layer (resist layer). Here, information for managing a wafer is expressed using a serial number. A predetermined mark representing the serial number is formed in the region on the wafer W by exposure. The writing device LM only needs to be able to form a predetermined mark on the wafer W, and its configuration is not limited.

  The reading device LR is a device for reading information written on the wafer by the writing device LM or a device similar to the writing device LM. The reading device LR is arranged on a wafer transfer path (not shown). The reading device LR includes, for example, a light source that emits light having a wavelength that the sensitive layer (resist layer) on the wafer does not sense, projects the light onto the wafer, and receives the reflected light, thereby receiving the resist layer on the wafer. A predetermined mark formed on the layer immediately below is read. The read result is sent to the main controller 20. Main controller 20 analyzes the received result, decodes (restores) the serial number, and reads information for managing the wafer encoded into the serial number.

  The transfer system 28 includes a transfer device 28A composed of, for example, an articulated robot that loads a wafer onto the wafer stage WST1 or WST2, and unloads the wafer from the wafer stage WST1 or WST2, and a control device 28B that controls the transfer device 28A. Included (see FIG. 4). The transport system 28 transports the wafer before exposure toward the wafer stage WST1 or WST2, and the exposed wafer toward the coater / developer (not shown) connected inline to the exposure apparatus 100 from the wafer stage WST1 or WST2. Transport.

  In addition, in the exposure apparatus 100 according to the present embodiment, an oblique incidence type multi-point focal position having the same configuration as that disclosed in, for example, US Pat. No. 5,448,332 is provided in the vicinity of the projection unit PU. A detection system (hereinafter abbreviated as a multi-point AF system) AF (not shown in FIG. 1, refer to FIG. 4) is provided. Here, as the multi-point AF system AF, one having a configuration in which the detection beam from the irradiation system is irradiated to each of a plurality of detection points on the surface of the wafer W1 (or W2) and each reflected light is received by the light receiving system. It has been. The detection signal of the multipoint AF system is supplied to the main controller 20 through an AF signal processing system (not shown) (see FIG. 4). Main controller 20 detects position information in the Z-axis direction of the surface of wafer W at each detection point based on the detection signal of the multipoint AF system, and based on the detection result, so-called focus of wafer W during scanning exposure is detected.・ Execute leveling control. A multi-point AF system is provided in the vicinity of the alignment detection system ALG so that surface position information (concave / convex information) on the wafer surface is acquired in advance during wafer alignment (EGA), and the surface position information and the wafer stage upper surface during exposure. The so-called focus leveling control of the wafer W may be executed using the measured value of another sensor that detects the position in the Z-axis direction.

  Further, in the exposure apparatus 100, a reticle alignment detection system 13 (not shown in FIG. 1, see FIG. 4) including a pair of TTR (Through The Reticle) alignment systems using light having an exposure wavelength is provided above the reticle stage RST. Is provided. The detection signal of the reticle alignment detection system 13 is supplied to the main controller 20 via an alignment signal processing system (not shown) (see FIG. 4).

  FIG. 4 shows the main configuration of the control system of the exposure apparatus 100. This control system is mainly configured of a main control device 20 composed of a microcomputer (or a workstation) for overall control of the entire apparatus.

  FIG. 5A shows an example of the wafer W used in this embodiment. On the wafer W, a plurality of (in this case, 68) shot regions (partition regions) S in which a pattern is formed are formed by exposure to the previous layer. A recording area MA is provided on the wafer W in an area that does not overlap with the plurality of shot areas S, in this case, in the peripheral area on the −Y side of the wafer W.

  5B and 5C show an enlarged example of the recording area MA provided on the wafer W. FIG. Various information necessary for managing the wafer in the exposure process is recorded in the recording area MA. Here, information is expressed using a serial number, and a mark corresponding to the serial number is written on the wafer W. In the example of FIG. 5B, a plurality of dots are written, and in the example of FIG. 5C, a barcode is written.

  In the example of FIG. 5B, 18 dots representing the serial number 100011000100010101 displayed in binary are written in the recording area MA on the wafer at a predetermined interval. Here, the dot corresponding to the numerical value 1 is written using the writing device LM. In the figure, written dots are represented using black circles. The numerical value 0 is represented using blank dots (no dots). In the figure, blank dots are represented by broken-line circles.

  The serial number displayed in dots in FIG. 5B includes information necessary for managing the wafer in the exposure process. The information includes information for specifying wafer stage WST1 or WST2 used when forming a pattern on wafer W. In addition, as an example, information for specifying the exposure apparatus 100, information for specifying a pattern to be formed, and the like are included. Further, if necessary for managing the wafer, other information may be further included in the serial number.

  The above 18 bits representing the serial number displayed in binary number indicate the manufacturer of the used exposure apparatus 100 composed of a start bit that means the start of a serial number composed of one bit and two bits. Information bit for specifying, information bit for specifying the used exposure apparatus 100 composed of four bits, information bit for identifying the used wafer stage composed of four bits (hereinafter referred to as stage specifying bits for convenience) , An information bit specifying a formed pattern composed of 6 bits, and an end bit meaning the end of a serial number composed of one bit. When each information bit is expressed using a decimal number, it is converted to 1, 0, 6, 2, 10, 1 as shown in the figure. Of these numerical values (numbers), from the remaining four numerical values excluding the numerical value 1 corresponding to the first start bit and the numerical value 1 corresponding to the sixth end bit, the “sixth” of the “0th” manufacturer. It is read that the “10th” (10th layer) pattern has been formed using the “second” wafer stage of the exposure apparatus.

  In the example of FIG. 5C, the same serial number as described above is displayed as a barcode.

  Next, based on the flowchart of FIG. 6 showing the processing algorithm of the control device 28B in the transfer system 28 under the main control device 20, the operation relating to the serial management of the wafer performed in the exposure apparatus 100 of the present embodiment. I will explain. Here, it is assumed that N wafers are successively processed by alternately using wafer stages WST1 and WST2.

  First, in step 200, the count value i of the counter indicating the wafer number is initialized (i ← 1).

In the next step 202, the controller waits for a wafer replacement command from the main controller 20. Then, when a wafer exchange command is issued, the process proceeds to step 204, and the wafer that has been exposed is unloaded from the i-th wafer stage (hereinafter referred to as “WST _i ” for convenience) using the transfer apparatus 20A. To do. It should be noted that, if the wafer on the wafer stage WST _i is not placed, not nothing.

  In the next step 206, the serial number recorded in the recording area MA on the i-th (here, the first) wafer is read using the reading device LR installed on the wafer transfer path (not shown). read.

  Here, for example, in the previous exposure process (the exposure process of the pattern of the previous layer) for the i-th (here, the first) wafer, the “second” of the “sixth” exposure apparatus of the “0th” manufacturer. It is assumed that the “tenth” layer pattern is formed using the wafer stage. In this case, when the information about the previous exposure process is encoded according to the above-described rules, it is converted into the serial number 1, 0, 6, 2, 10, 1 or its binary display 100011000100010101. This binary number display of the serial number is displayed on the recording area MA on the wafer W2 with dots as shown in FIG. 5B or as a bar code as shown in FIG. 5C.

  Therefore, in this step 206, the control device 28B uses the “second” wafer stage of the “sixth” exposure device “sixth” exposure device of the “zeroth” manufacturer in the previous exposure process for the wafer. It is read that the pattern is formed on the wafer.

  However, since only wafer serial management in the exposure apparatus 100 is considered here, the target wafer is the exposure apparatus 100 (that is, the “sixth” exposure apparatus of the “0th” manufacturer). In other words, exposure of a plurality of layers including at least the 10th layer and the 11th layer is performed. In other words, the manufacturer and the exposure apparatus number are common to all wafers.

Therefore, in the next step 208, main controller 20, to determine the 2 ⁰ of the digit value of the binary representation of the count value i, whether the value of the least significant bit stage specific bits match Thus, it is determined whether or not the pattern of the previous layer (in this case, the tenth layer) for the i-th wafer is formed using the same wafer stage as the wafer stage WST _i to be used.

In this case, the pattern of the front layer of the i-th (here, 1st) wafer is formed using the “second” wafer stage, ie, wafer stage WST2, while the i-th wafer stage WST _i is the wafer stage WST _i. since a stage WST1, numeric significant bits of stage specific bit whereas a "0", 2 ⁰ value of the digit of the binary representation of the count value i is "1". Accordingly, the determination in step 208 is denied, and the process proceeds to step 212 to notify the main controller 20 of the mismatch between the two stages together with the serial number read earlier. In response to this notification, main controller 20 writes information indicating the processing of the next exposure process on the i-th wafer, as will be described later. The control target position (and / or speed) of stage WST _i is set to (i + 1) -th wafer stage WST _{(i + 1)} (if i = 1, wafer stage WST2) and wafer stage WST _i (if i = 1) The wafer position is controlled while being corrected based on the position control characteristic relationship with the wafer stage WST1), for example, the difference (individual difference) in the position control results.

The other hand, the pattern of the previous layer of the i-th wafer, if it was formed by using the same wafer stage and the wafer stage WST _i to now used, the determination at step 208 is affirmative, step 210 The main controller 20 is notified of the coincidence of both stages together with the serial number read earlier. Upon receiving this notification, main controller 20 writes information indicating the processing of the next exposure process on the i-th wafer, as will be described later, and at the time of this wafer exposure, The control target position (and / or speed) of wafer stage WST _i is determined based on the alignment result and the baseline, and the wafer position is controlled based on the target position.

In any case, after the above notification, the process proceeds to step 214, and the i-th wafer is changed to the i-th wafer stage WST _i (ie, if i is an odd number, wafer stage WST1, i is an even number) Is loaded onto wafer stage WST2) using transfer device 28A, and then proceeds to step 216.

  In step 216, it is determined whether or not the count value i is greater than or equal to N. If this determination is negative, the process proceeds to step 218, where the count value i is incremented by 1 (i ← i + 1). Then, the process returns to step 202, and the processing (including determination) after step 204 is repeated until the determination in step 216 is affirmed.

  When the determination in step 216 is affirmed, the process of this routine is terminated.

  Next, parallel processing operations performed using the wafer stages WST1 and WST2 in the exposure apparatus 100 of the present embodiment will be described with reference to FIGS. Further, the following description of the operation will be made with reference to a number of drawings, and the same members may or may not be labeled with the same members for each drawing. In other words, although the reference numerals described in the drawings are different, the drawings have the same configuration regardless of the presence or absence of the reference numerals.

  In FIG. 7, step-and-scan exposure is performed on the wafer W1 placed on the wafer stage WST1 in the moving area during exposure in the vicinity of the projection unit PU. In the position, a state is shown in which the wafer is exchanged between the transfer system (not shown) and wafer stage WST2 by transfer device 28A (not shown in FIG. 7, see FIG. 4). In the present embodiment, the loading position is determined as the position of wafer stage WST2 (and WST1) where reference mark plate FM is positioned within the detection area of alignment system ALG within the alignment movement area near alignment system ALG. ing.

At the time of this wafer exchange, in response to a wafer exchange command from main controller 20, as described above, exposed wafer (here, wafer W2 ₀ ) is unloaded from wafer stage WST2 by controller 28B. The serial number recorded on the wafer (here, wafer W2) is read using the reading device LR (see FIG. 7). Then, according to the reading result of the serial number, it is determined whether or not the wafer stage used at the time of forming the pattern on the front layer of wafer W2 matches wafer stage WST2 in the loading position by control device 28B. The determination result is notified to main controller 20 together with the serial number read earlier.

  In FIG. 7, for convenience of explanation, the reading device LR is shown in the drawing, but does not mean the installation location.

  Then, when the next wafer W2 is loaded onto wafer stage WST2 by transfer device 28A, main controller 20 reads the contents of information indicating the next exposure process to be written on wafer W2 as follows. To decide.

  That is, when the main controller 20 is notified that the two wafer stages match together with the serial number, the main controller 20 uses the wafer stage WST2 of the exposure apparatus 100 to use the next layer (here, the eleventh layer). ) Is determined as information to be written. On the other hand, when the main controller is notified that the two wafer stages do not coincide with the serial number, the main controller uses the wafer stage WST1 instead of the wafer stage WST2 of the exposure apparatus 100 to use the next layer ( Here, the formation of the pattern of the eleventh layer is determined as information to be written. The reason for this will be described later.

  Then, as shown in FIG. 8, main controller 20 writes information indicating the next exposure process determined above into recording area MA on wafer W2 using writing device LM. Here, when the two wafer stages coincide with each other, the “eleventh” pattern is formed using the “second” wafer stage of the “sixth” exposure apparatus of the “sixth” manufacturer. Is written as a dot similar to FIG. 5B or a barcode similar to FIG. 5C. On the other hand, if the two wafer stages do not match, the “eleventh” pattern is formed using the “first” wafer stage of the “sixth” exposure apparatus of the “zeroth” manufacturer. Is written as a dot similar to FIG. 5B or a barcode similar to FIG. 5C. Alternatively, information bits may be added to record more detailed information.

  After the wafer exchange is completed, while the wafer stage WST2 is stopped at the loading position, the main controller 20 performs the writing process using the writing device LM as shown in FIGS. In addition, the Y interferometer 19 and the X interferometers 117 and 127 are reset (the origin is reset) while the second reference mark on the reference mark plate FM can be detected using the alignment system ALG. Then, main controller 20 calculates the position coordinates of the second reference mark on the alignment coordinate system defined by the measurement axes of Y interferometer 19 and X interferometers 117 and 127 based on the detection result. .

  In the present embodiment, alignment is performed so that the detection of the reference mark FM using the alignment system ALG and the process of writing information about the exposure process using the writing device LM can be performed in parallel. The installation positions of the system ALG and the writing device LM are determined.

  Next, as shown in FIG. 9, main controller 20 measures the position of wafer stage WST2 using interferometers 19, 117, 127, and performs wafer alignment using alignment system ALG. EGA disclosed in Japanese Patent Application Laid-Open No. 61-44429 (corresponding to US Pat. No. 4,780,617) is executed. Then, main controller 20 converts the position coordinates on the alignment coordinate system of the plurality of shot areas on wafer W2 obtained by EGA into position coordinates based on the position of the second reference mark.

  When exposure on wafer W1 on wafer table WTB1 and wafer alignment (EGA) on wafer W2 on wafer table WTB2 are completed, main controller 20 moves wafer stage WST1 to the black thick arrow as shown in FIG. Wafer stage WST2 is moved from the alignment movement area to the exposure movement area along the path indicated by the white thick arrow from the exposure movement area to the alignment movement area (loading position) along the path shown. Let At this time, main controller 20 moves wafer stage WST1 while managing the position using Y interferometer 16 and X interferometers 116 and 117. Similarly, Y controller 18 and X interferometers 126 and 127 are moved. The wafer stage WST2 is moved while using it to manage the position.

Note that switching of the X interferometer occurs with the movement of wafer stages WST1 and WST2. For example, when wafer stage WST1 moves along a path indicated by a black thick arrow, projection points of length measuring beams B116 ₁ and B116 ₂ of X interferometer 116 deviate from reflecting surface 27a of stage WST1 during the movement. Instead, the measurement beams B117 ₁ and B117 ₂ of the X interferometer 117 are projected onto the reflecting surface 27a. Therefore, main controller 20 switches the interferometer for measuring the X and θy positions of wafer stage WST1 from X interferometer 116 to X interferometer 117. Further, when wafer stage WST2 moves along the path indicated by the white thick arrow, the projection points of length measuring beams B127 ₁ and B127 ₂ of X interferometer 127 are moved from reflecting surface 27c of stage WST2 during the movement. Instead, the measurement beams B126 ₁ and B126 ₂ of the X interferometer 126 are projected onto the reflecting surface 27c. Therefore, main controller 20 switches the interferometer for measuring the X and θy positions of wafer stage WST2 from X interferometer 127 to X interferometer 126.

  It should be noted that there is a section where the length measurement beams of X interferometers 116 and 117 are not projected onto reflecting surface 27a of stage WST1 on the movement path of wafer stage WST1. Similarly, there is a section in which the measurement beams of X interferometers 126 and 127 are not projected onto reflecting surface 27c of stage WST2 on the movement path of wafer stage WST2. Therefore, in these sections, main controller 20 uses encoder system 150 to manage the positions of both stages WST1 and WST2.

  Then, main controller 20 moves wafer stage WST2 to position reference mark plate FM directly below projection optical system PL. Then, a pair of first reference marks on the reference mark plate FM is detected using the reticle alignment detection system 13 (see FIG. 4), and the reticle alignment mark on the reticle R corresponding to the first reference mark is projected onto the wafer surface. Detect the relative position of the image.

  Based on this detection result and the position coordinates of each shot area on wafer W2 with reference to the previously obtained second reference mark, main controller 20 projects the projection position (projection optical system PL) of the pattern of reticle R. And the relative positional relationship between each shot area on the wafer W2. Main controller 20 calculates the target position (or target speed) of wafer stage WST2 based on the calculation result, and based on the calculated target position, as shown in FIG. While managing the position of wafer stage WST2 using 116 and 126, step-and-scan exposure is performed to transfer the pattern of reticle R to each shot area on wafer W2.

  Here, main controller 20 has previously notified from controller 28B that the wafer stage used when forming the pattern on the front layer of wafer W2 did not match wafer stage WST2 at the loading position. If the notification indicates that, in calculating the target position of the wafer stage WST2, the relationship between the position control characteristics of the wafer stages WST1 and WST2, for example, the difference in position control results (individual difference), The calculated target position is corrected. On the other hand, if the previously notified notification from the control device 28B is a notification indicating that both wafer stages match, the calculated target value is not corrected.

  Here, main controller 20 measures the relationship between the position control characteristics of both wafer stages WST1 and WST2, for example, the difference between the position control results, at the time of activation of exposure apparatus 100, and corrects the measurement results as correction information (calibration information). ) Is stored in the memory.

  Main controller 20 may correct the target position of reticle stage RST during scanning exposure instead of correcting the target position of wafer stage WST2. Alternatively, main controller 20 corrects the measurement value of reticle interferometer 116 or interferometer system 118 (interferometers 17, 116, 126) at the time of scanning exposure instead of correcting the target position of wafer stage WST2 or reticle stage RST. It may be corrected. In short, when the two wafer stages do not coincide with each other, as a result, the relative position between the pattern of the reticle R and the wafer W2 (the pattern already formed in each shot area) becomes the pattern of the previous layer. The exposure for forming and the exposure for forming the current layer pattern may be adjusted in the same manner as in the case of using the same wafer stage.

  Thus, in the case where the two wafer stages do not match, in the same manner as when the same wafer stage is used, the relative position between the reticle R pattern and the wafer during scanning exposure is adjusted. As described above, the information indicating the next exposure process is information indicating that a wafer stage different from the actually used wafer stage is used.

In parallel with the above-described exposure operation of wafer stage WST2, in response to a wafer exchange command from main controller 20, wafer on wafer stage WST1 is exchanged by controller 28B. That is, as shown in FIG. 11, the exposed wafer (here, wafer W1) is unloaded from wafer stage WST1 at the loading position by control device 28B via transfer device 28A, and the next wafer ( Here, the serial number recorded on the wafer W1 ₂ ) is read using the reading device LR (see FIG. 11). Then, according to the reading result of the serial number by the control device 28B, the determination result of whether or not the wafer stage used at the time of forming the pattern of the front layer of the wafer W2 matches the wafer stage WST1 in the loading position is Notified to the main controller 20.

  In FIG. 11, for convenience of explanation, the reading device LR is shown in the drawing, but it does not mean the installation location.

Then, by the transfer device 28A, when the next wafer W1 ₂ is loaded on the wafer stage WST1, main controller 20 in the same manner as described above, to be written on the wafer W1 _2, information indicating the next exposure step of determining the contents, as shown in FIG. 12, by using the writing device LM, written in the recording area MA on the wafer W1 _2.

  After the wafer exchange is finished, while the wafer stage WST1 is stopped at the loading position, the main controller 20 is shown in FIGS. 11 and 12 in parallel with the writing process using the writing device LM. In addition, the Y interferometer 19 and the X interferometers 117 and 127 are reset (the origin is reset) while the second reference mark on the reference mark plate FM can be detected using the alignment system ALG. Then, after calculating the position coordinates of the second reference mark on the alignment coordinate system based on the detection result, main controller 20 uses interferometers 19, 117, 127 as shown in FIG. Wafer alignment (EGA) is performed while measuring the position of wafer stage WST. Then, main controller 20 converts the position coordinates on the alignment coordinate system of the plurality of shot areas on wafer W2 obtained by EGA into position coordinates based on the position of the second reference mark.

  When the wafer alignment (EGA) for wafer W1 on wafer table WTB1 and the exposure for wafer W2 on wafer table WTB2 are completed, main controller 20 moves wafer stage WST1 to the thick black arrow as shown in FIG. Wafer stage WST2 is moved from the moving area during exposure to the moving area during alignment (loading position) along the path indicated by the white thick arrow along the path indicated. Let At this time, main controller 20 moves wafer stage WST1 while managing the position using Y interferometer 16 and X interferometers 116, 117, and similarly, Y interferometer 18 and X interferometers 126, 127 are moved. The wafer stage WST2 is moved while managing the position using.

When the movement of wafer stage WST1 is completed, as shown in FIG. 15, the main controller 20, according to the procedure similar to that described above, to start the exposure of wafer W1 ₂ on the wafer stage WST1. Upon exposure processing for the W1 _2, the main controller 20, similar to the above, according to the previous notification content, if necessary, per the calculation of the target position of the wafer stage WST1, wafer stages WST1 and WST2 with The calculated target position is corrected based on the position control characteristic relationship, for example, the difference (individual difference) in the position control results.

  In parallel with the above exposure operation, under the control of the main controller 20, the wafer exchange on the wafer stage WST2, the reading of the serial number, the writing of new information, etc. are performed in the same procedure as described above. Wafer alignment (EGA) is performed.

  Thereafter, the parallel processing operation using wafer stage WST1 and WST2 described above is repeatedly executed by main controller 20 and controller 28B.

  In the parallel processing operation using the above-described two wafer stages WST1 and WST2, one or more patterns are already formed on the wafer to be loaded, and information on the exposure process for forming the pattern is recorded on the recording area on the wafer. The explanation was given on the assumption that it was recorded in MA. However, when the exposure of the first layer (first layer) is performed, nothing is recorded in the recording area of the wafer to be exposed (bare wafer). Therefore, when the bare device is loaded onto the wafer stage using the transfer device 28A in order to form the first layer pattern, the control device 28B also reads the reading device LR as with the wafer on which the pattern is formed. Is used to read the information recorded in the recording area MA. When there is no read information, the control device 28B notifies the main control device 20 to that effect. The main controller 20 receives the notification, determines that the wafer to be exposed from now on is a bare wafer, and that the exposure of the first layer is performed, and forms the pattern of the “first” layer. The meaning serial number may be written on the wafer together with other information.

  As described above, according to the exposure apparatus 100 of the present embodiment, the information (that is, the pattern) recorded in the recording area MA provided outside the plurality of partitioned areas (shot areas) of the wafer W by the reading device LR. Information for specifying the wafer stage used for the transfer, the exposure apparatus used and its manufacturer, and information for specifying the transferred pattern, etc.) are read and based on the read information by the control device 28B. Then, it is determined whether or not the wafer stage used when the previous pattern is formed on the wafer W is coincident with the wafer stage scheduled to be used next. Then, the main controller 20 controls when the pattern of the reticle R is superimposed on the previous pattern on the wafer W by using the projection optical system PL by the above-described step-and-scan exposure operation. At least one of the reticle stage drive system 11 and the stage drive system 124 is controlled in accordance with the determination result by the apparatus 28B, whereby the pattern of the reticle R and the wafer stage (wafer W placed on the wafer stage) are controlled. The relative position is controlled.

  In this case, based on the determination result of the control device 28B, the wafer stage used when forming the previous pattern and the wafer stage scheduled to be used next (the wafer stage actually used in this embodiment) are used. It is possible to know in advance the relationship of characteristics at the time of alignment. Therefore, when the next pattern is aligned with the previous pattern and formed on the wafer, the relationship between the pattern and the wafer (wafer stage) is adjusted by the main controller 20 in consideration of the relationship. Then, by controlling at least one of the reticle stage drive system 11 and the stage drive system 124, high-precision superposition is possible.

  In the above-described embodiment, from the viewpoint of giving the highest priority to throughput, the wafers sent from the transfer system are alternately loaded on wafer stages WST1 and WST2, and if necessary, the reticle and wafer at the time of scanning exposure Although the case where the relative position is adjusted has been illustrated, the present invention is not limited to this. For example, when it is allowed to take a relatively long time for wafer replacement, the pattern of the previous layer on the wafer is determined based on the result of reading the serial number. The wafer may be always loaded on the same wafer stage used for forming the wafer. Next, such a modification will be described.

  FIG. 16 is a flowchart showing a processing algorithm of the control device 28B in the transfer system 28 related to the serial management of the wafer, which is performed by the exposure apparatus of the modification. Hereinafter, the processing algorithm of the modified example will be described along this flowchart. Here, for simplification of description, a case will be described in which exposure processing is performed on N wafers selected from a large number of wafers continuously sent from the transfer system.

  First, in step 300, the count value i of the counter indicating the wafer number is initialized (i ← 1). Here, the count value i means the number of the wafer that is actually exposed by the exposure apparatus among the plurality of wafers continuously sent from the transfer system.

In the next step 302, the main controller 20 waits for a wafer exchange command. When the command of the wafer exchange is performed, the routine proceeds to step 304, using the transfer device 20A, unloads the exposed wafer from the i-th wafer stage WST _i. If no wafer is placed on wafer stage WSTi, nothing is done.

  In the next step 306, it is determined whether or not the i-th wafer has been transferred by the transfer system 28 by checking whether or not there is a wafer at the position of the reading device LR. If this determination is negative, the system waits for the next wafer to be transferred by the transfer system 28. If the next wafer has been transferred, or if there is a next wafer from the beginning and the determination in step 306 is affirmative, the process proceeds to step 308.

  In Step 308, the serial number recorded in the recording area MA on the i-th (here, the first) wafer is read using the reading device LR.

In the next step 310, by determining the 2 ⁰ of the digit value of the binary representation of the count value i, whether the value of the least significant bit stage specific bits match, the i-th wafer It is determined whether the pattern of the previous layer is formed using the same wafer stage as wafer stage WST _i to be used from now on.

  If this determination is negative, the process returns to step 306 and waits for the next wafer to be transferred by the transfer system 28. Thereafter, the loop of step 306 → 308 → 310 is repeated until the determination in step 310 is affirmed.

On the other hand, if the determination in step 310 is affirmative, that is, if the pattern of the previous layer for the i-th wafer has been formed using the same wafer stage as wafer stage WST _i to be used, step 312 is performed. Then, the main control device 20 is notified of the serial number read earlier. Upon receiving this notification, main controller 20 writes information indicating the processing of the next exposure process on the i-th wafer as described above, and at the time of exposure of this wafer, The control target position (and / or speed) of wafer stage WST _i is determined based on the alignment result and the baseline, and the wafer position is controlled based on the target position.

After the above notification, the process proceeds to step 314, and the i-th wafer is transferred to the i-th wafer stage WST _i (ie, wafer stage WST1 when i is an odd number, and wafer stage WST2 when i is an even number). Then, after loading using the transfer device 28A, the process proceeds to step 316.

  In step 316, it is determined whether or not the count value i is greater than or equal to N. If this determination is negative, the process proceeds to step 318, where the count value i is incremented by 1 (i ← i + 1). Thereafter, the processing after step 302 (including determination) is repeated until the determination in step 316 is affirmed.

  When the determination in step 316 is affirmed, the process of this routine is terminated.

  As described above, according to this modification, the wafer stage used for forming the pattern of the previous layer is always used for forming the pattern of the next layer. Thereby, it is possible to reliably avoid the occurrence of an overlay error due to the difference in the wafer stage to be used. However, if the determination in step 310 is negative, the processing in steps 306, 308, and 310 is repeated until the determination in step 310 is positive. Therefore, from the viewpoint of emphasizing throughput, the exposure on the wafer on one wafer stage, the wafer exchange on the other wafer stage and the wafer alignment are performed in parallel, and the time required for the exposure is greater This modification is particularly suitable when the time required for replacement and wafer alignment is long.

  If the determination in step 310 is negative, a flag is set, the wafer is placed in a temporary standby place near the loading position, and when the next wafer stage is instructed to replace the wafer, It is also possible to look at the flag and load the wafer at the temporary standby place onto the next wafer stage.

  In the wafer used in the embodiment and the modified example, the recording area MA in which information necessary for managing the wafer in the exposure process is written does not overlap with the shot area in which a pattern is formed on the periphery of the wafer W. It was decided to provide it. However, the present invention is not limited to this. For example, it may be provided on a scribe line between shot areas. Further, similarly to the alignment mark attached to each shot area, the recording area MA may be attached to each shot area. In that case, information can be recorded for each shot area. In addition, the information expressed using the serial number is displayed in binary dot display or bar code display, but these are only examples, and can be written on the wafer using the writing device LM and the reading device LR. Any mark may be used as long as the mark can be read from the wafer using the mark.

  In the above-described embodiment and modification, the case where the exposure apparatus includes the writing apparatus LM as well as the reading apparatus LR has been described. However, the writing apparatus is connected to the outside of the exposure apparatus, for example, inline to the exposure apparatus. It may be provided in a coater / developer.

  In the embodiment and the modification, the writing device LM is installed in the vicinity of the alignment system ALG in order to record information necessary for managing the wafer in the exposure process during wafer alignment (EGA). It was decided. However, information recording may be performed at a timing other than the wafer alignment (EGA), for example, at the time of exposure or after unloading the wafer. Therefore, the writing device LM may be installed at an appropriate position in accordance with the timing of recording information. In addition, before loading a wafer onto the wafer stage, a reading device LR is installed on the wafer conveyance path in order to read information recorded on the wafer. However, the reading of information may be executed before the start of exposure, for example, after the wafer is placed on the wafer stage or at the time of wafer alignment (EGA). Therefore, the reading device LR may be installed at an appropriate position according to the timing of reading information. When reading the information after the wafer is placed on the wafer stage, the wafer stage used for forming the pattern of the previous layer is always used for forming the pattern of the next layer. In this case, since it becomes necessary to replace the wafer after it is once mounted, it is desirable to adopt such a wafer management method when the exposure time is considerably longer than the wafer replacement time and the alignment time.

  In the embodiment and the modification, the writing device LM and the reading device LR are installed at different positions as independent devices. However, the writing apparatus LM and the reading apparatus LR may be integrated, and an apparatus in which both apparatuses are integrated may be installed inside the exposure apparatus.

  In the embodiment and the modification, the manufacturer and the exposure apparatus number are assumed to be common to all the wafers based on the assumption that only the serial management of the wafer in the exposure apparatus 100 is considered. In a lithography system including a plurality of exposure apparatuses and a host computer that comprehensively manages these exposure apparatuses, for example, the host computer manages the position control characteristics for each wafer stage of each exposure apparatus, thereby The serial management of the wafer described in the embodiment can be extended to be performed regardless of the manufacturer and the exposure apparatus number.

  In the above-described embodiment and modification, the case where the present invention is applied to a twin-stage type exposure apparatus that uses two wafer stages WST1 and WST2 has been described. However, the present invention is not limited to this, and three or more wafer stages are used. The present invention may be applied to an exposure apparatus to be used. In the above embodiment and the modification, each of wafer stages WST1 and WST2 is independently driven using a planar motor. However, the present invention is not limited to this, and a linear motor or the like may be used.

  In the above-described embodiment, the case where the present invention is applied to a dry type exposure apparatus that exposes the wafer W without using liquid (water) has been described. No. 99/49504, European Patent Application Publication No. 1,420,298, International Publication No. 2004/055803 Pamphlet, Japanese Patent Application Laid-Open No. 2004-289126 (corresponding US Pat. No. 6,952,253) As described in the above, an immersion space including an optical path of illumination light is formed between the projection optical system and the wafer, and the wafer is exposed with illumination light through the liquid in the projection optical system and the immersion space. The present invention can also be applied to an exposure apparatus.

  In the above embodiment, the case where the present invention is applied to a scanning exposure apparatus such as a step-and-scan method has been described. However, the present invention is not limited to this, and the present invention is applied to a stationary exposure apparatus such as a stepper. May be. The present invention can also be applied to a step-and-stitch reduction projection exposure apparatus, a proximity exposure apparatus, or a mirror projection aligner that synthesizes a shot area and a shot area.

  In addition, the projection optical system in the exposure apparatus of the above embodiment may be not only a reduction system but also an equal magnification and an enlargement system, and the projection optical system PL may be not only a refraction system but also a reflection system or a catadioptric system. The projected image may be either an inverted image or an erect image. In addition, the illumination area and the exposure area described above are rectangular in shape, but the shape is not limited to this, and may be, for example, an arc, a trapezoid, or a parallelogram.

The light source of the exposure apparatus of the above embodiment is not limited to the ArF excimer laser, but a pulsed laser light source such as a KrF excimer laser (output wavelength 248 nm) or F ₂ laser (output wavelength 157 nm), g-line (wavelength 436 nm), i It is also possible to use an ultrahigh pressure mercury lamp that emits a bright line such as a line (wavelength 365 nm). A harmonic generator of a YAG laser or the like can also be used. In addition, as disclosed in, for example, US Pat. No. 7,023,610, a single wavelength laser beam in an infrared region or a visible region oscillated from a DFB semiconductor laser or a fiber laser is used as vacuum ultraviolet light. For example, a harmonic that is amplified by a fiber amplifier doped with erbium (or both erbium and ytterbium) and wavelength-converted into ultraviolet light using a nonlinear optical crystal may be used.

  In the above embodiment, it is needless to say that the illumination light IL of the exposure apparatus is not limited to light having a wavelength of 100 nm or more, and light having a wavelength of less than 100 nm may be used. For example, the present invention can be applied to an EUV exposure apparatus that uses EUV (Extreme Ultraviolet) light in a soft X-ray region (for example, a wavelength region of 5 to 15 nm). In addition, the present invention can be applied to an exposure apparatus using a charged particle beam such as an electron beam or an ion beam.

  In the above-described embodiment, a light transmission mask (reticle) in which a predetermined light-shielding pattern (or phase pattern / dimming pattern) is formed on a light-transmitting substrate is used. Instead of this reticle, For example, as disclosed in US Pat. No. 6,778,257, an electronic mask (variable shaping mask, which forms a transmission pattern, a reflection pattern, or a light emission pattern based on electronic data of a pattern to be exposed, as disclosed in US Pat. No. 6,778,257. For example, a non-light emitting image display element (spatial light modulator) including a DMD (Digital Micro-mirror Device) may be used.

  Further, for example, the present invention can be applied to an exposure apparatus (lithography system) that forms line and space patterns on a wafer by forming interference fringes on the wafer.

  Further, as disclosed in, for example, US Pat. No. 6,611,316, two reticle patterns are synthesized on a wafer via a projection optical system, and one scan exposure is performed on one wafer. The present invention can also be applied to an exposure apparatus that performs double exposure of shot areas almost simultaneously.

  Note that the object on which the pattern is to be formed in the above embodiment (the object to be exposed to the energy beam) is not limited to the wafer, but other objects such as a glass plate, a ceramic substrate, a film member, or a mask blank. But it ’s okay.

  The use of the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing. For example, an exposure apparatus for liquid crystal that transfers a liquid crystal display element pattern onto a square glass plate, an organic EL, a thin film magnetic head, an image sensor ( CCDs, etc.), micromachines, DNA chips and the like can also be widely applied to exposure apparatuses. Further, in order to manufacture reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, etc., glass substrates or silicon wafers, etc. The present invention can also be applied to an exposure apparatus that transfers a circuit pattern.

  An electronic device such as a semiconductor element includes a step of designing a function / performance of the device, a step of manufacturing a reticle based on the design step, a step of manufacturing a wafer from a silicon material, and the exposure apparatus (pattern forming apparatus) of the above-described embodiment. ) A lithography step for transferring a mask (reticle) pattern onto a wafer, a development step for developing the exposed wafer, an etching step for removing exposed members other than the portion where the resist remains by etching, and etching is completed. It is manufactured through a resist removal step for removing unnecessary resist, a device assembly step (including a dicing process, a bonding process, and a package process), an inspection step, and the like. In this case, in the lithography step, the exposure method described above is executed using the exposure apparatus of the above embodiment, and a device pattern is formed on the wafer. Therefore, a highly integrated device can be manufactured with high productivity.

  The pattern forming method and pattern forming apparatus of the present invention are suitable for forming a plurality of patterns on a wafer by using a plurality of wafer stages. The device manufacturing method of the present invention is suitable for the production of micro devices.

It is a figure which shows schematically the structure of the exposure apparatus of one Embodiment. 2A is a front view showing wafer stage WST1 in FIG. 1, and FIG. 2B is a plan view showing wafer stage WST1. It is a top view which shows arrangement | positioning of the interferometer system with which the exposure apparatus of FIG. 1 is provided. It is a block diagram which shows the main structures of the control system of the exposure apparatus of one Embodiment. FIG. 5A is a view showing an example of a wafer, and FIGS. 5B and 5C are views showing an example of marks for recording various information necessary for managing the wafer in the exposure process. It is a flowchart which shows the processing algorithm regarding the serial management of the wafer of the control apparatus inside a conveyance system. Exposing the wafer stage WST1, the wafer W1 is performed, the wafer replacement, the wafer stage WST2, i.e. unloads the exposed wafer W2 _0, is recorded in the recording area on the next wafer W2 using reader LR FIG. 6 is a diagram showing a state in which the next wafer W2 is loaded on the stage WST2 according to the read information. Wafer stage WST1 exposes wafer W1, and wafer stage WST2 detects reference mark FM using alignment system ALG and manages the wafer in a recording area on wafer W2 using writing device LM. It is a figure which shows the state in which various information required in order to do is written. In wafer stage WST1, wafer W1 is exposed, and in wafer stage WST2, wafer alignment (EGA) is performed on wafer W2. Wafer stage WST1 for which exposure on wafer W1 has been completed is moved from exposure movement area AE to alignment movement area, and wafer stage WST2 for which wafer alignment (EGA) for wafer W2 has been completed is moved from alignment movement area to exposure movement area AE. It is a figure which shows the state currently moved to. In the wafer stage WST1 wafer exchange, i.e. it unloads the exposed wafer W1, read the information recorded in the recording area on the next wafer W1 ₂ with reader LR, the following according to the read information wafer W1 ₂ is a diagram showing a state in which ₂ is loaded on stage WST1 and wafer stage WST2 is exposing wafer W2. In the wafer stage WST1, together with the reference mark FM is detected using alignment system ALG, various information necessary for managing the wafer is written in the recording area on the wafer W1 ₂ using a writing device LM, wafer In stage WST2, it is a figure which shows the state in which exposure is performed with respect to wafer W2. Wafer alignment on the wafer stage WST1, the wafer W1 ₂ (EGA) is performed, and is a view showing a state in which exposure is performed on the wafer stage WST2 wafer W2. The wafer stage WST1 to wafer alignment (EGA) is completed for the wafer W1 ₂ is moved from the alignment time movement area to the exposure time movement area AE, during alignment the wafer stage WST2 that exposure is completed for the wafer W2 from the exposure time movement area AE mobile It is a figure which shows the state currently moved to the area | region. Exposing the wafer stage WST1 in the wafer W1 ₂ is performed, the wafer stage WST2 wafer exchange, i.e. unloads the exposed wafer W2, recorded in the recording area on the next wafer W2 ₂ with reader LR has been read information, the next wafer W2 ₂ are according to the read-out information is a diagram showing a state of being loaded on the stage WST2. It is a flowchart which shows the process algorithm regarding the serial management of the wafer of the control apparatus inside a conveyance system based on a modification.

Explanation of symbols

  16, 17, 18, 19 ... Y interferometer, 50 ... stage device, 100 ... exposure device, 116,117 ... X interferometer, 118 ... interferometer system, 124 ... stage drive system, 126,127 ... X interferometer, ALG ... Alignment system, LM ... Writing device, LR ... Reading device, PL ... Projection optical system, PU ... Projection unit, W, W1, W2 ... Wafer, WST1, WST2 ... Wafer stage, WTB1, WTB2 ... Wafer table, R ... Reticle, RST ... Reticle stage.

Claims (23)

A pattern forming method for forming a plurality of patterns on an object using a plurality of stages,
The information recorded on the object is read, and the stage used to form the previous pattern on the object based on the information indicating the previous exposure process for the object included in the information , and the next use is scheduled Determining whether the stage being matched matches;
Placing the object from which the information has been read on the next stage scheduled for use;
If the stage used to form the previous pattern and the stage scheduled to be used next do not match based on the determination result of the determining step, the stage scheduled to be used next The position control characteristic of one of the mask stage that holds and moves the mask on which the next pattern is formed in synchronization with the stage is calibrated to the position control characteristic of the stage used when forming the previous pattern. If the stage used for forming the previous pattern and the stage scheduled to be used next coincide with each other, the position control characteristic is not calibrated and is superimposed on the previous pattern. And forming a next pattern on the object together. A pattern forming method for forming a plurality of patterns on an object using a plurality of stages,
Read information recorded on the object, and based on the information, whether or not the stage used when forming the previous pattern on the object and the stage scheduled to be used next are the same A step of judging;
Taking into account the judgment result of the judgment step, forming a next pattern on the object in superposition with the previous pattern;
Wherein only the objects determined to be placed on the basis of the judgment result of the step of determining, the step and that mounted on the stage of use in the following to be scheduled; method including pattern formation. In a region other than the region where the pattern on the object is formed, a pattern forming method according to claim 1 or 2 further comprising the step of writing information indicating the next exposure step for said object. The pattern forming method according to claim 3 , wherein the information indicating the next exposure step includes information indicating a specific stage to be used in the next exposure step of the object. The pattern forming method according to claim 4 , wherein in the writing step, information indicating the specific stage is determined as a part of information to be written on the object in accordance with a determination result of the determination step. The pattern forming method according to claim 5 , wherein, in the writing step, if it is determined in the determining step that the two stages do not coincide with each other, the stage used when forming the previous pattern is set as the specific stage. . The information indicating the next exposure step, information specifying the pattern formed on the object, claim 3 in which at least one of information identifying a pattern forming device used to form the pattern is further included The pattern formation method as described in any one of -6 . The information is expressed using a serial number,
The pattern forming method according to claim 3 , wherein in the writing step, a mark corresponding to the serial number is written on the object to be written. Upon the read pattern forming method according to any one of claims 1-8 for reading the information expressed with the serial number corresponding to the mark recorded to an object to be read. The pattern forming method according to claim 8 , wherein the mark is a dot or a barcode. The object has a sensitive layer;
In the step of the formation, the formation of the next pattern in the sensitive layer by irradiating an energy beam, the pattern forming method according to any one of claims 1-10. Forming a pattern on an object using the pattern forming method according to any one of claims 1 to 11 ;
And a step of processing the object on which a pattern is formed. A pattern forming apparatus for forming a plurality of patterns on an object,
A plurality of stages holding the object and movable within a predetermined area;
A drive system for driving the plurality of stages;
A pattern generation device for generating the plurality of patterns on the object;
A reader for reading information recorded on the object;
Based on the information indicating the previous exposure process for the object included in the read information , the stage used to form the previous pattern on the object and the stage scheduled to be used next are one. A judging device for judging whether or not it is done;
A transfer device for placing the object from which the information has been read on the stage scheduled to be used next;
When the next pattern is formed by superimposing the previous pattern on the object, the stage used for forming the previous pattern and the next use are scheduled based on the determination result of the determination device. If the stage does not match, the position control characteristic of one of the stage scheduled to be used next and the mask stage that holds and moves the mask on which the next pattern is formed in synchronization with the stage Is calibrated to the position control characteristic of the stage used when forming the previous pattern, and the stage used when forming the previous pattern matches the stage that is scheduled to be used next. If, without performing calibration of the position control characteristics, the control system and for controlling the drive system; patterning device comprising a. A pattern forming apparatus for forming a plurality of patterns on an object,
A plurality of stages holding the object and movable within a predetermined area;
A drive system for driving the plurality of stages;
A pattern generation device for generating the plurality of patterns on the object;
A reader for reading information recorded on the object;
A determination device that determines, based on the read information, whether or not the stage used when forming the previous pattern on the object matches the stage that is scheduled to be used next;
A control system that controls at least one of the drive system and the pattern generation device in accordance with a determination result of the determination device when forming a next pattern superimposed on the previous pattern on the object;
The determination device of the determination result only the object it is determined to put on the basis of the conveying device and for placing the stage used in the following to be scheduled; Rupa turn-forming apparatus comprising a. 15. The pattern forming apparatus according to claim 13 , further comprising a writing device that writes information indicating a next exposure process on the object in an area other than an area where the pattern is formed on the object. The pattern forming apparatus according to claim 15 , wherein the information indicating the next exposure process includes information indicating a specific stage to be used in the next exposure process of the object. The pattern forming apparatus according to claim 16 , wherein the writing apparatus determines information indicating the specific stage as a part of information to be written on the object according to a determination result of the determination apparatus. The pattern forming apparatus according to claim 17 , wherein when the determination apparatus determines that the two stages do not match, the writing apparatus uses the stage used when forming the previous pattern as the specific stage. The information indicating the next exposure process further includes at least one of information specifying a pattern formed on the object and information specifying a pattern forming apparatus used to form the pattern. The pattern formation apparatus as described in any one of 15-18 . The information is expressed using a serial number,
The pattern forming apparatus according to claim 15 , wherein the writing apparatus writes a mark corresponding to the serial number on the object to be written. 21. The pattern forming apparatus according to claim 13 , wherein the reading device reads information expressed using a serial number corresponding to a mark recorded on an object to be read. The pattern forming apparatus according to claim 20 or 21 , wherein the mark is a dot or a barcode. The object has a sensitive layer;
The pattern formation apparatus according to any one of claims 13 to 22 , wherein the pattern generation apparatus forms the pattern by irradiating the sensitive layer with an energy beam.

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