JP2012079735A - Mask contraction correction optimizing method, exposing method and device manufacturing method, and device manufacturing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely align a pattern.SOLUTION: In a reticle contraction correction model for describing contraction amounts of two reticles used in a double patterning method, parameters relating to contraction (reticle contraction correction parameters (a time constant and a saturation value)) are optimized. Then, using the optimized reticle contraction correction model, the pattern is aligned to a target layer of a wafer, which is a next exposure object. Thereby, without influence of a correction error due to heat deformation of the reticle, the target pattern can be precisely aligned to the target layer on the wafer.

Description

  The present invention relates to a mask expansion / contraction correction optimization method, an exposure method, a device manufacturing method, and a device manufacturing system. More specifically, each of a plurality of objects is overlapped with an already formed base pattern and a target. Expansion and contraction correction of masks used for the first exposure and the second exposure, respectively, when sequentially performing a process of forming a pattern by overlapping a pattern through a plurality of lithography processes including exposure and development on the layer. A mask stretch correction optimization method suitable for so-called double patterning, an exposure method using the mask stretch correction optimization method, a device manufacturing method using the exposure method, and a plurality of objects, respectively. On the other hand, a lithography process that includes exposure and development on the target layer, superimposed on the already formed base pattern. The process of forming by overlapping pattern through a plurality of times, to sequentially perform device manufacturing system.

  In the manufacturing process of electronic devices such as semiconductor elements and liquid crystal display elements, step-and-repeat type projection exposure apparatuses (steppers), step-and-scan type projection exposure apparatuses (scanners) and the like are mainly used. . In this type of exposure apparatus, illumination light is irradiated onto a wafer or a glass plate or the like (hereinafter collectively referred to as a wafer) coated with a sensitive agent (photoresist) through a reticle (mask) and a projection optical system. The pattern formed on the reticle is transferred to each of a plurality of shots arranged on the wafer.

  In particular, in the manufacture of semiconductor elements, since dozens of layers of patterns are superimposed on each other (because they are stacked), high overlay accuracy between layers (high alignment accuracy between patterns) is required. The Therefore, in recent years, in wafer alignment (wafer alignment) in the exposure process, an alignment mark formed on a part of a plurality of shots is detected, and the detection result is statistically processed, so that all shots are processed. An enhanced global alignment (EGA) method for obtaining an array and a distortion (in-shot error) of a pattern in a shot with high accuracy has been widely adopted (see, for example, Patent Document 1 and Patent Document 2).

  However, during the exposure process (lot processing), the reticle can be deformed by heat generated by absorbing illumination light. Further, since the same reticle is used to sequentially expose wafers in lot units (one lot is 25 or 50), the degree of reticle (mask) deformation increases each time the wafer is exposed. The distortion of the projected image of the pattern is enlarged. Therefore, in addition to the above-mentioned EGA wafer alignment, reticle thermal deformation correction is performed to predict the thermal deformation of the reticle and adjust the distortion of the projected image of the pattern based on the result.

  On the other hand, a so-called double process method (double patterning method) has been proposed in which a fine pattern exceeding the resolution limit of an exposure apparatus is formed by repeating a lithography process twice with the miniaturization of a pattern of a semiconductor element or the like. ing. Therefore, reticle thermal expansion / contraction correction corresponding to the double patterning method is required.

US Pat. No. 4,780,617 US Pat. No. 6,876,946

  According to the first aspect of the present invention, for each of a plurality of objects, the pattern is superimposed on the target layer by performing a lithography process including exposure and development a plurality of times on the target layer. A mask expansion / contraction correction optimization method for optimizing the mask expansion / contraction correction used in each of the first exposure and the second exposure when the processes to be formed are sequentially performed. And detecting a plurality of first marks formed together with a first pattern constituting a part of the target pattern on the target layer of one object, and using the detection result to form the first pattern. A first step of obtaining an expansion amount of the first mask to be obtained and obtaining a first residual between the expansion amount of the first mask and a predicted value of the expansion amount obtained from the first correction model describing the expansion amount; The above A plurality of second marks formed together with a second pattern constituting a part of the target pattern on the get layer is detected, and the expansion / contraction amount of the second mask used for forming the second pattern is determined using the detection result. A second step of determining a second residual between the expansion amount of the second mask and a predicted value of the expansion amount obtained from the second correction model describing the expansion amount; and the first residual and the A parameter related to the amount of expansion / contraction of the mask for at least one of the first and second correction models, using a statistical sum of at least one of the second residual and the difference between the first and second residuals. And a third step of optimizing the mask expansion / contraction correction optimization method.

  According to this, since the parameter relating to the expansion / contraction amount of the mask corresponding to at least one of the first and second correction models describing the expansion / contraction amount of the first and second masks is optimized, the mask expansion / contraction correction is optimized. As a result, the pattern alignment accuracy can be improved.

  According to the second aspect of the present invention, each of the plurality of objects is superimposed on the already formed base pattern, and the pattern is superimposed on the target layer through a plurality of lithography steps including exposure and development. An exposure method for sequentially performing the processes to be formed, and using the mask expansion / contraction correction optimization method of the present invention, optimizes a parameter related to the mask expansion / contraction amount for at least one of the first and second correction models. Aligning the first pattern with a target layer of another object of the plurality of objects using the first correction model, and transferring the first pattern onto the target layer; Aligning the second pattern with the target layer of the other object using the second correction model, and transferring the second pattern onto the target layer. Exposure method, is provided.

  According to this, the corresponding first or second pattern is separated using at least one of the first and second correction models in which the parameter related to the mask expansion / contraction amount is optimized by the mask expansion / contraction correction optimization method of the present invention. Align with the target layer of the object. As a result, the target pattern can be accurately aligned with the target layer on the object without being affected by the thermal expansion / contraction correction error of the mask.

  According to a third aspect of the present invention, there is provided a device manufacturing method comprising: forming a pattern on a plurality of objects using the exposure method of the present invention; and developing the object on which the pattern is formed. A method is provided.

  According to the fourth aspect of the present invention, each of a plurality of objects is overlaid on the already formed ground pattern, and the target layer is overlaid with a pattern through a plurality of lithography steps including exposure and development. A device manufacturing system that sequentially performs processing to be formed, an exposure apparatus that transfers a pattern formed on a mask to the plurality of objects; and a measuring apparatus that has a function of detecting marks formed on the objects And one or more computers including a host computer connected to the exposure apparatus and the measurement apparatus, the exposure apparatus and the control computer for the measurement apparatus, and the one or more computers. Any one of the plurality of computers including a part of the target pattern on the target layer of one of the plurality of objects. A plurality of first marks formed together with the first pattern to be detected using the measuring device, and using the detection result, an expansion / contraction amount of the first mask used for forming the first pattern is obtained, and the first mark A second pattern that forms a part of the target pattern in the target layer by obtaining a first residual between the expansion / contraction amount of one mask and the predicted value of the expansion / contraction amount obtained from the first correction model describing the expansion / contraction amount A plurality of second marks formed together are detected using the measuring device, and the amount of expansion / contraction of the second mask used for forming the second pattern is obtained using the detection result, and the expansion / contraction of the second mask is determined. A second residual of the predicted value of the amount of expansion and contraction obtained from the second correction model describing the amount and the amount of expansion and contraction, the first residual, the second residual, and the first and second Statistical sum of at least one of the differences between the residuals Using a device manufacturing system for optimizing parameters according to expansion and contraction of the mask for at least one of the first and second correction model is provided.

  According to this, since the parameter relating to the expansion / contraction amount of the corresponding mask is optimized for at least one of the first and second correction models describing the expansion / contraction amount of the first and second masks, respectively, the mask expansion / contraction correction is optimized. As a result, the pattern alignment accuracy can be improved.

It is a figure showing roughly composition of a device manufacture system of one embodiment. It is a figure which shows schematically an example of a structure of the exposure apparatus of FIG. It is a figure which shows the flow of a process in a device manufacturing process. 4 (A) to 4 (J) are diagrams for explaining the formation process of the pattern formed on the wafer, and are enlarged sectional views showing a partial region of one shot on the wafer. is there. FIGS. 5A and 5B are diagrams showing residuals of shot scaling X and shot scaling Y before and after optimization of the reticle expansion / contraction correction model, respectively. 6 is a flowchart (part 1) illustrating an outline of a processing algorithm executed by a host in the device manufacturing system according to the embodiment. 6 is a flowchart (part 2) illustrating an outline of a processing algorithm executed by a host in the device manufacturing system according to the embodiment. FIG. 8A is a diagram for explaining an example of the arrangement of sample shots of multi-point EGA in shots in advance measurement, and FIG. 8B is a sample of multi-point EGA in shots in alignment measurement during lot processing. It is a figure for demonstrating an example of arrangement | positioning of a shot. FIG. 9A is a diagram showing an example of the arrangement of alignment marks provided in sample shots on a wafer measured in the pre-measurement and post-measurement, and FIG. It is a figure which shows an example of arrangement | positioning of the alignment mark provided in the sample shot measured by point EGA measurement. It is a flowchart which shows an example of the subroutine of step 564 of FIG.

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

  FIG. 1 schematically shows the configuration of a device manufacturing system according to an embodiment. The device manufacturing system 1000 is a system constructed in a device manufacturing factory for processing a substrate, for example, a semiconductor wafer (hereinafter referred to as “wafer”) and manufacturing a microdevice. As shown in FIG. 1, a device manufacturing system 1000 includes an exposure apparatus 100, a track 200 disposed adjacent to the exposure apparatus 100, an analysis apparatus 500, and a host computer (hereinafter referred to as “host”). 600) and a device manufacturing processing apparatus group 900. In FIG. 1, the bold arrows indicate the flow (movement) of the wafer, and the other solid arrows indicate the data flow.

  FIG. 2 schematically shows an example of the configuration of the exposure apparatus 100. The exposure apparatus 100 is a step-and-scan projection exposure apparatus (that is, a scanner). The exposure apparatus 100 includes an illumination system IOP, a reticle stage RST that holds a reticle R, a projection optical system PL, a wafer stage WST on which a wafer W is placed, a control system for these, and the like.

  The illumination system IOP includes a light source and an illumination optical system connected to the light source via a light transmission optical system. The illumination optical system includes, for example, an illumination uniformizing optical system including an optical integrator, a beam splitter, a reticle blind, and the like (all not shown) as disclosed in, for example, US Patent Application Publication No. 2003/0025890. . Illumination system IOP uses illumination light IL to illuminate a slit-shaped illumination area set in a reticle blind on reticle R on which a circuit pattern or the like is drawn (a long and narrow rectangular shape extending in the X-axis direction (the direction orthogonal to the plane of FIG. 2)). Illuminate with almost uniform illumination. As the illumination light IL, for example, ArF excimer laser light (wavelength 193 nm) (or KrF excimer laser light (wavelength 248 nm)) is used.

  Reticle stage RST is arranged below illumination system IOP in FIG. 2 (on the −Z side). On reticle stage RST, reticle R on which a pattern is formed is fixed, for example, by vacuum suction. Here, reticle stage RST can be finely driven in a horizontal plane (XY plane) by a reticle stage drive system 22 including a linear motor and the like, and also has a scanning direction (here, the Y axis in the horizontal direction in FIG. 2). Driving at a scanning speed specified in a predetermined stroke range. Position information (including rotation information about the Z axis) of the reticle stage RST in the XY plane is, for example, about 0.25 nm by a reticle laser interferometer (hereinafter referred to as “reticle interferometer”) 16 via a movable mirror 15. Is always detected with a resolution of. Position information of reticle stage RST from reticle interferometer 16 is sent to main controller 50, which drives reticle stage RST via reticle stage drive system 22 based on the position information of reticle stage RST. (Position control).

  Projection optical system PL is arranged below reticle stage RST in FIG. 2 (on the −Z side), and the direction of optical axis AX is the Z-axis direction. As the projection optical system PL, for example, a bilateral telecentric refraction system including a plurality of lens elements arranged at a predetermined interval along the Z-axis direction parallel to the optical axis AX is used. The projection magnification β of the projection optical system PL is, for example, ¼ (or ５). For this reason, when the reticle R is illuminated by the illumination light IL from the illumination system IOP, the illumination light IL that has passed through the reticle R passes through the projection optical system PL and is within the illumination area (illumination area) of the illumination light IL. A reduced image (partial inverted image) of the reticle R pattern is formed in an area (exposure area) conjugated to the illumination area on the wafer W coated with a photoresist (sensitive agent; hereinafter abbreviated as resist). (A latent image of the pattern is formed on the resist).

  The exposure apparatus 100 is provided with an imaging characteristic correction device for correcting imaging characteristics of the projection optical system PL, for example, various aberrations. This imaging characteristic correction device corrects changes in imaging characteristics of the projection optical system PL itself due to changes in atmospheric pressure, absorption of illumination light, and the like, and shot regions (for example, the previous layer) of a preceding specific layer on the wafer W ( Hereinafter, the projection image of the pattern on the reticle R is distorted in accordance with the distortion of the pattern transferred to the shot). Examples of the imaging characteristics of the projection optical system PL include spherical aberration (aberration at the imaging position), coma aberration (magnification aberration), astigmatism, curvature of field, and distortion (distortion). The imaging characteristic correction apparatus has a function of correcting imaging characteristics (various aberrations). In the following description, the imaging characteristic correction apparatus mainly uses a mask (reticle) by absorbing exposure power during lot processing. ) Distortion (including magnification aberration) of the projected image (transfer image) due to expansion and contraction of the image is corrected over time.

  In FIG. 2, the lens element 27 that is the closest to the reticle R constituting the projection optical system PL is fixed to the support member 28, and the lens elements 29, 30, 31,... Following the lens element 27 are lens mirrors of the projection optical system PL. It is fixed to the cylinder 38. The support member 28 is projected optically via a plurality of (three in this case) drive elements that can be expanded and contracted, for example, piezo elements 11a, 11b, and 11c (however, the drive element 11c on the back side of the paper is not shown in FIG. 2). It is connected to the lens barrel 38 of the system PL. The drive voltage applied to the drive elements 11a, 11b, and 11c is independently controlled by the imaging characteristic control unit 12, whereby the lens element 27 is arbitrarily inclined and optical axis with respect to the plane orthogonal to the optical axis AX. It is configured to be movable in a direction parallel to AX. The driving amount of the lens element 27 by each driving element is strictly measured by a position sensor (not shown), and the position is maintained at a target position by servo control. Note that the optical axis AX of the projection optical system PL indicates the common optical axis of a fixed lens element such as the lens element 29.

  In the above description, for the sake of convenience of explanation, it is assumed that only the lens element 27 is movable. However, actually, in the projection optical system PL, a plurality of lens elements or lens groups include the above lens. Like the element 27, it is configured to be movable. Further, in the imaging characteristic correction apparatus, in addition to the configuration for correcting distortion of the projection image by moving a part of the optical elements that constitute the projection optical system PL, A configuration in which the distortion of the projected image is corrected by controlling the gas pressure (adjusting the refractive index) may be employed.

  Wafer stage WST is arranged below projection optical system PL in FIG. 2 (on the −Z side). On wafer stage WST, wafer W is held by vacuum suction or the like via wafer holder 9.

  Wafer stage WST is driven with a predetermined stroke in the X-axis direction and Y-axis direction by wafer stage drive system 24 including a linear motor and the like, and also rotates in the Z-axis direction and the Z-axis rotation direction (θz direction). It is finely driven in a rotating direction (θx direction) around and a rotating direction around the Y axis (θy direction). That is, the wafer holder 9 can be tilted in any direction with respect to the best imaging plane of the projection optical system PL by the wafer stage drive system 24, and can be finely moved in the optical axis AX direction (Z-axis direction). It is configured to be rotatable around a Z axis parallel to the axis AX.

  Position information (including yawing (rotation in the θz direction) information) and tilt information (pitching (rotation in the θx direction) information and rolling (rotation in the θy direction) information) of the wafer stage WST in the XY plane are the wafer laser. An interferometer (hereinafter abbreviated as a wafer interferometer) 18 is constantly detected through a movable mirror 17 with a resolution of, for example, about 0.25 nm. The position information (or speed information) of wafer stage WST is sent to main controller 50, and main controller 50 determines the position of wafer stage WST in the XY plane (in the θz direction) based on the position information (or speed information). (Including rotation) is controlled via the wafer stage drive system 24.

  Further, a reference mark plate FM having a surface set substantially at the same height as the surface of wafer W is fixed to the upper surface of wafer stage WST. On the surface of the fiducial mark plate FM, a first fiducial mark for reticle alignment and a second fiducial mark for baseline measurement of the alignment system 8 described later are formed in a predetermined positional relationship.

  On the side surface of the projection optical system PL, an off-axis alignment system 8 for detecting an alignment mark (wafer mark) formed on each shot on the wafer W, a second reference mark on the reference mark plate FM, and the like. Is provided. The alignment system 8 illuminates the wafer surface including the wafer mark or the like using an optical system provided in the interior, and guides reflected light from the wafer surface to an alignment sensor provided in the interior using the optical system. A signal corresponding to the reflected light is photoelectrically detected using an alignment sensor. The detected signal has, for example, a waveform corresponding to the unevenness or reflectance distribution of the wafer surface. In the alignment system, a waveform (mark waveform) corresponding to the mark is extracted from the detected waveform data, and the position coordinate of the mark waveform in the detection field of the alignment sensor is detected based on the extraction result. In the alignment system, the position of the wafer mark or the like in the XY coordinate system is calculated based on the position coordinate of the detected mark waveform and the position coordinate of the detection visual field itself of the alignment sensor. The detection result of the alignment system 8 is sent to the main controller 50 via an alignment signal processing system (not shown).

  Further, in the vicinity of the lower end portion of the projection optical system PL, position information (surface position information) regarding the Z-axis direction of the surface of the wafer W at a plurality of detection points in the exposure area and in the vicinity thereof is detected. An oblique incidence type multi-point focal position detection system (13, 14) disclosed in the specification of No. 5,448,332 and the like is provided. The multipoint focal position detection system includes an irradiation optical system 13 that emits an imaged light beam obliquely with respect to the optical axis AX toward the best image formation plane of the projection optical system PL, and a reflected light beam from the surface of the wafer W as a slit. And a light receiving optical system 14 for receiving light through The wafer surface position information detected by the multipoint focus position detection system (13, 14) is supplied to the main controller 50 for focus / leveling control of the wafer W.

  In addition, the exposure apparatus 100 is provided with a pair of reticle alignment systems (not shown) as disclosed in, for example, US Pat. No. 5,646,413 above the reticle stage RST. The reticle alignment system is composed of a TTR (Through The Reticle) alignment system using light having the same wavelength as the illumination light IL. The detection signal of the reticle alignment system is supplied to main controller 50 via an alignment signal processing system (not shown).

  The main controller 50 is composed of, for example, a microcomputer (or workstation), and comprehensively controls each part of the exposure apparatus 100.

  Next, a series of operations performed by the exposure apparatus 100 configured as described above will be briefly described.

  Prior to exposure, main controller 50 causes wafer W to be loaded onto wafer holder 9 using a wafer transfer system (not shown), reticle alignment, baseline measurement of alignment system 8, and wafer alignment (for example, EGA (described later) Preparation work such as Enhanced Global Alignment) or multi-point EGA within shot) is performed. The above reticle alignment, baseline measurement, and the like are disclosed in detail in the aforementioned US Pat. No. 5,646,413.

  Main controller 50 sequentially performs scanning exposure on reticle R on all shots on wafer W based on the results of reticle alignment and baseline measurement described above and the results of wafer alignment (which will be described later). Transfer the pattern.

  In scanning exposure for each shot on wafer W, main controller 50 scans reticle stage RST and wafer stage WST while monitoring measurement information (positional information) by reticle interferometer 16 and wafer interferometer 18. Move to the start position (acceleration start position). Then, main controller 50 relatively drives reticle stage RST and wafer stage WST in the Y-axis direction, but in opposite directions. Here, when reticle stage RST and wafer stage WST reach their respective target speeds, the pattern area of reticle R starts to be illuminated by illumination light IL, and scanning exposure is started.

  Main controller 50 determines that the speed Vr of reticle stage RST in the Y-axis direction and the movement speed Vw of wafer stage WST in the Y-axis direction at a speed ratio corresponding to the projection magnification of projection optical system PL, particularly during the above-described scanning exposure. The reticle stage RST and wafer stage WST are synchronously controlled so as to be maintained. At this time, main controller 50 adjusts the synchronous drive of both stages RST and WST, or drives the movable lens via the imaging characteristic correction device, so that the projection image of the pattern on reticle R onto wafer W is displayed. Correct distortion.

  Then, different areas of the pattern area of the reticle R are sequentially illuminated with the illumination light IL, and the illumination of the entire pattern area is completed, thereby completing the scanning exposure of the first shot on the wafer W. Thereby, the circuit pattern of the reticle R is reduced and transferred to the first shot via the projection optical system PL.

  When the scanning exposure for the first shot is completed, main controller 50 moves (steps) wafer stage WST to the scanning start position (acceleration start position) for the next second shot. Then, similarly to the above, the scanning exposure for the second shot is performed. Thereafter, the same operation is performed for the third and subsequent shots. In this manner, the stepping operation between shots and the scanning exposure operation for the shots are repeated, and the pattern of the reticle R is transferred to all shots on the wafer W by the step-and-can method.

  Returning to FIG. 1, in the track 200, a composite measurement / inspection instrument 120 capable of performing various measurement / inspections on the wafer before and after exposure of the wafer by the exposure apparatus 100, and a resist ( A coater / developer (hereinafter abbreviated as C / D) 110 is provided for applying the photosensitive agent) and developing the exposed wafer.

  The measurement / inspection instrument 120 can operate independently of the exposure apparatus 100 and the C / D 110. Further, the measurement / inspection instrument 120 can output the measurement / inspection results to the outside via a communication network in the system.

  In the post-measurement inspection of the measurement / inspection instrument 120, in addition to the defect / foreign matter inspection on the wafer W, the formation state of the device pattern and the like on the wafer W after exposure (post-event) transferred by the exposure apparatus 100 and developed by the C / D 110 And the overlay state is measured. More specifically, the measurement / inspection instrument 120 detects an alignment mark formed on the wafer together with the pattern. As a result, the absolute position (deviation from the design position) of the mark formed in the current process layer and the relative position (position deviation) between the marks formed in different layers are obtained as a formation error and an overlay error, respectively. It is done. A measurement result obtained by the measurement / inspection instrument 120 is supplied to the host 600 or the main controller 50 of the exposure apparatus 100. Note that when the measurement / inspection instrument 120 analyzes the overlay state of the base pattern formed in the original process (layer) prior to the exposure for the current process (layer), the measurement / inspection instrument 120 was exposed prior to the exposure of the target wafer. This is used when measuring the formation state of the underlying pattern formed on the wafer and analyzing the thermal deformation of the reticle.

  The analysis apparatus 500 is an apparatus that operates independently of the exposure apparatus 100, the C / D 110, and the measurement / inspection instrument 120. The analysis apparatus 500 collects various data (for example, processing data of the apparatus) from various apparatuses, and analyzes data relating to a series of processes for the wafer W. As hardware for realizing such an analysis apparatus 500, for example, a personal computer (hereinafter, abbreviated as “PC” as appropriate) can be employed. In this case, the analysis process is realized by executing an analysis program executed by a CPU (not shown) of the analysis apparatus 500. This analysis program is recorded on a medium (information recording medium) such as a CD-ROM, and is executed in a state where it is installed on the PC from the medium.

  The analysis apparatus 500 performs a simulation on wafer alignment of the exposure apparatus 100 based on the measurement results of the exposure apparatus 100 and the measurement / inspection instrument 120, and performs alignment-related parameters, correction parameters for synchronous scanning control, adjustment parameters for the projection optical system, and the like. To optimize.

  The exposure apparatus 100, the C / D 110, and the measurement / inspection instrument 120 are connected in-line to each other. Here, the in-line connection means that the apparatuses and the processing units in each apparatus are connected via a transfer apparatus that automatically transfers the wafer W such as a robot arm and / or a slider. By the in-line connection, the transfer time of the wafer W between the exposure apparatus 100 and the C / D 110 can be remarkably shortened.

  The exposure apparatus 100, the C / D 110, and the measurement / inspection instrument 120 connected in-line can be regarded as one substrate processing apparatus (100, 110, 120) as a unit. The substrate processing apparatus (100, 110, 120) has an application process for applying a sensitive agent such as a resist to the wafer W, and an exposure process for transferring a mask or reticle pattern onto the wafer W to which the sensitive agent has been applied. In addition, a developing process for developing the wafer after the exposure process is performed.

  In the device manufacturing system 1000, a plurality of exposure apparatuses 100, C / Ds 110, and measurement / inspection instruments 120 are provided. Each substrate processing apparatus (100, 110, 120) and device manufacturing processing apparatus group 900 is installed in a clean room in which temperature and humidity are controlled. In addition, data communication can be performed between devices via a predetermined communication network (for example, LAN: Local Area Network). This communication network is a so-called intranet communication network provided for a customer's factory, business office or company.

  In the substrate processing apparatus (100, 110, 120), a plurality of wafers (for example, 25 or 50) are processed as one unit (referred to as a lot). In the device manufacturing system 1000, wafers are processed and commercialized using one lot as a basic unit.

  In this device manufacturing system 1000, the measurement / inspection instrument 120 is placed in the track 200 and connected inline with the exposure apparatus 100 and the C / D 110. However, the measurement / inspection instrument 120 is disposed outside the track 200, Adjacent inline connection may be used, or the exposure apparatus 100 and C / D 110 may be configured offline.

  The device manufacturing system 1000 includes a CVD (Chemical Vapor Deposition) apparatus 910, an etching apparatus 920, a CMP (Chemical Mechanical Polishing) apparatus 930, an oxidation / ion implantation apparatus 940, and the like as the device manufacturing processing apparatus group 900. The CVD apparatus 910 is an apparatus that generates a thin film on a wafer. The etching apparatus 920 is an apparatus that performs etching on the developed wafer. In this embodiment, the etching apparatus 920 is provided with an ashing apparatus that removes resist and the like. The CMP apparatus 930 is a polishing apparatus that planarizes the surface of a wafer by chemical mechanical polishing. The oxidation / ion implantation apparatus 940 is an apparatus for forming an oxide film on the surface of the wafer or implanting impurities into a predetermined position on the wafer. Similarly to the exposure apparatus 100, the CVD apparatus 910, the etching apparatus 920, the CMP apparatus 930, and the oxidation / ion implantation apparatus 940 are also provided with a transfer path for enabling transfer of wafers between them. The device manufacturing processing apparatus group 900 includes various apparatuses that perform dicing processing, packaging processing, bonding processing, and the like, although not shown.

  The host 600 manages and manages the entire device manufacturing system 1000. Therefore, the host 600 controls and manages the exposure process performed in the exposure apparatus 100 and manages the scheduling of the exposure apparatus 100. A management controller for the exposure apparatus 100 may be provided separately from the host 600. In the present embodiment, the host 600 uses the analysis device 500 to perform, for example, an alignment error analysis (reticle expansion / contraction correction) described later.

  Next, a device manufacturing process in the device manufacturing system 1000 will be described with reference to FIGS. 3 and 4A to 4J.

  FIG. 3 shows a processing flow in the device manufacturing process. This processing flow is scheduled and managed by the host 600. Although not explicitly shown in FIG. 3, the wafers W are processed in lot units. 4A to 4J are enlarged cross-sectional views of a partial region of one shot on the wafer W. FIG.

  In the present embodiment, the line width of the target layer 31 on the wafer W (see FIG. 4A, etc.) having a pitch P in the X-axis direction and a line width of P / 2 (that is, a space width of P / 2) The goal is to form a line-and-space pattern (hereinafter referred to as an L / S pattern) having a ratio to the space width of 1: 1 using a double process method (double patterning method). As an example, the pitch P is 64 nm, and at this time, the line width P / 2 is 32 nm. The resolution limit in the dry exposure of the exposure apparatus 100 is about 60 nm in the line width when the phase shift reticle is used, and the line width of the L / S pattern formed on the target layer 31 is the resolution limit. It is almost 1/2. Further, the dimension of the pattern used in the description of the present embodiment is a dimension at the stage of the projection image, and the reticle R of the pattern is used by using the projection magnification β from the reticle R of the projection optical system PL to the wafer W. The above dimensions are 1 / β times (4 times for β = 1/4).

[Film formation]
First, as a film forming process, as shown in FIG. 4A, a CVD apparatus 910 generates (deposits) a target layer 31 made of an interlayer insulating film such as an organic polymer on the wafer W. On the target layer 31, a hard mask layer 32 made of ceramics such as a silicon oxide film or a silicon nitride film and having different reactivity to etching with both the target layer 31 and the resist is laminated. Instead of using the hard mask layer 32, a bi-layer (two-layer) resist can be used.

[Resist coating]
Next, the wafer W on which the target layer 31 and the hard mask layer 32 are formed is transferred to the C / D 110, and the surface (hard mask layer) of the wafer W is transferred to the C / D 110 as shown in FIG. A resist is applied to the upper surface 32) (the resist layer 33 is laminated). Here, a positive resist is used as an example.

[First exposure process]
Next, wafer W on which resist layer 33 is formed is transferred to exposure apparatus 100 and loaded onto wafer stage WST in exposure apparatus 100. Then, the exposure apparatus 100 performs the first wafer alignment and exposure processing on the wafer W.

  Here, on reticle stage RST of exposure apparatus 100, a reticle used for the first exposure (hereinafter referred to as reticle R1 for convenience of explanation) is mounted, and reticle R1 has a period as an example. A light shielding pattern that is elongated in the Y-axis direction in the direction P (this is referred to as the X-axis direction) P (the dimension at the stage of the projected image as described above, and the same applies hereinafter) and a transmission portion having a width P in the X-axis direction are defined as the X axis. A phase shift type L / S pattern in which phase shifters (phase shift portions) are provided so as to alternately invert phases in a series of adjacent transmission portions is formed. Here, it is assumed that, prior to loading of wafer W onto wafer stage WST, reticle alignment, baseline measurement of alignment system 8, and the like are performed.

  In this case, for example, the exposure apparatus 100 sets the numerical aperture NA of the projection optical system PL to a large value (for example, 0.92) and the coherence factor (σ value) of the illumination optical system to a small value (for example, 0.2). The pattern of the reticle R is projected onto the wafer W by dry exposure. The phase shift reticle is not limited to the spatial frequency modulation type, and may be another type such as a halftone type, or may be combined with modified illumination (for example, annular illumination or multipolar illumination). Further, instead of the phase shift reticle, a normal reticle may be used as the reticle R1, and illumination conditions may be dipole illumination that illuminates the reticle R1 with illumination light inclined symmetrically in the X-axis direction.

The main controller 50 performs the first wafer alignment (EGA measurement) on the wafer W using the alignment system 8, and performs a step-and-scan exposure operation based on the result, and the pitch of the reticle R1. An image of the 2P L / S pattern is transferred to each shot on the wafer W. As a result, the exposed portion of the resist (the portion irradiated with light) is increased in solubility in the developer (such a change occurs), and as a result, as shown in FIG. It consists portions which were not exposed to the layer 33, a latent image corresponding to the device patterns having a line portion 33 ₂ is formed.

Exposure in the first exposure process, in FIG. 4 (B), the line width of the line portion 33 ₂ of the resulting device pattern in P, the width of the space portion is set to be P. Thus, when the exposure amount is set so that the ratio of the line width to the space width is 1: 1, the change in the exposure amount (light intensity) of the L / S pattern image near the sensitivity of the resist. Since the change amount of the position is small and the tolerance of the exposure amount error is large, the resist pattern can be easily formed with high accuracy.

[Development processing]
Next, the exposed wafer W is transferred to the C / D 110, and the wafer W (resist layer 33) is developed by the C / D 110. After development, as shown in FIG. 4 (B), the wafer W resist image of (hard mask layer 32) line portion 33 ₂ on (hereinafter, the resist image 33 using the resist image by using a line portion the same reference numerals ₂ ).

[First etching process]
Next, the wafer W is transferred to the etching apparatus 920, and the first resist slimming process and the subsequent etching process are performed in the etching apparatus 920. The first resist slimming treatment, etching the etching time, by setting so that the resist image 33 ₂ of the width P is a resist image 33 ₁ of a width P / 2 as shown in FIG. 4 (C), a resist image 33 ₂ It is processing to do. As a result, on the hard mask layer 32, a resist image 33 ₁ having a width P / 2 (that is, a space width of 3P / 2) is arranged in a pitch 2P in the X-axis direction. A resist pattern with a ratio of 1: 3 is formed. In this case, it is possible that only manage the etching time, readily form a resist image 33 ₁ of a width P / 2.

Then, the etching of the hard mask layer 32 is performed using the resist image ₃₃₁ as a mask. After etching, as shown in FIG. 4 (D), a hard mask pattern (first pattern) 32 ₁ is obtained by arranging the hard mask layer 32 having a width P / 2 in the X-axis direction at a pitch 2P. Thereafter, the resist layer 33 (resist image 33 ₁ ) is peeled off from the wafer W by an ashing device (not shown).

[Resist coating]
Then, the wafer W hard mask pattern 32 ₁ on the target layer 31 is formed is transported to the C / D110, the C / D110, as shown in FIG. 4 (E), the surface of the wafer W (Hard resist is applied to the mask pattern 32 ₁ above) (resist layer 34 is formed).

[Second exposure process]
Next, the wafer W on which the resist layer 34 is formed is transferred to the exposure apparatus 100, and the exposure apparatus 100 performs a second exposure process on the wafer W. Here, prior to loading of wafer W onto wafer stage WST, reticle R1 on reticle stage RST is replaced with a reticle used for the first exposure (hereinafter referred to as reticle R2 for convenience of explanation). It is assumed that reticle alignment and baseline measurement of the alignment system 8 are performed. Then, the main controller 50 performs the second wafer alignment (EGA measurement) on the wafer W using the alignment system 8. In the second EGA, the same reference layer (underlayer) mark (the same number of marks and mark arrangement) as in the first EGA is detected in the same procedure.

Based on the alignment result, the main controller 50 performs a step-and-scan exposure operation, and the device pattern on the reticle R2 is transferred onto the wafer W. As an example, on the reticle R, a light-shielding pattern elongated in the Y-axis direction and having a width P in the periodic direction (this is the X-axis direction) (the dimension at the stage of the projected image as described above, the same applies hereinafter) and the X-axis direction Phase shift type L / S in which transmission parts having a width P are arranged at a pitch of 2P in the X-axis direction, and phase shifters (phase shift parts) are provided so that phases are alternately inverted in a series of adjacent transmission parts A pattern is formed. In this case, the pattern on the reticle R differs from the pattern on the reticle R1 by 180 ° in the X-axis direction. For this reason, the positional relationship in the X-axis direction between the image of the L / S pattern with the pitch 2P on the reticle R2 and each shot of the wafer W is 180 ° different from that in the case of the first exposure. While the positional relationship between the reticle R and the wafer W is adjusted, the second exposure is performed. As a result, the exposed portion of the resist (the portion irradiated with light) has increased solubility in the developer (such a change occurs), and as a result, as shown in FIG. latent image corresponding to the device patterns having a line portion 34 ₂ formed of a portion not exposed to the layer 34 is formed.

Exposure amount in the second exposure also in FIG. 4 (F), the line width of the resist image 34 ₂ to be obtained by P, the width of the space portion is set to be P. Thus, a resist pattern having a ratio of line width to space width of 1: 1 can be easily formed with high accuracy. Furthermore, the resist image 34 ₂ is disposed on the two intermediate hard mask pattern 32 ₁ adjacent which are arranged at a pitch 2P in the X-axis direction, respectively.

[Development processing]
Next, the exposed wafer W is transferred to the C / D 110, and the wafer W (resist layer 34) is developed by the C / D 110. After development, as shown in FIG. 4 (F), the wafer W hard mask pattern (first pattern) is formed on (the target layer 31) 32 resist image of the line portion 34 ₂ with ₁ (hereinafter, the line of this resist image referred to as resist image 34 ₂ using parts the same reference numerals) is formed.

[Second etching process]
Next, the wafer W is transferred to the etching apparatus 920, and a second resist slimming process and a subsequent etching process are performed in the etching apparatus 920. Second resist slimming treatment, etching the etching time, by setting so that the resist image 34 ₂ of the width P is a resist image 34 ₁ of a width P / 2 as shown in FIG. 4 (G), a resist image 34 ₂ It is processing to do. As a result, on the target layer 31, the ratio between the line width and the space width of 1: a first periodic pattern consisting of the resist image 34 ₁ of a width P / 2 of the 3 (second pattern), the line width and the space width A mask layer 35 composed of a second periodic pattern (first pattern) composed of the hard mask pattern 32 _{1 having} a width P / 2 of 1: 3 is formed. Since the first periodic pattern and the second periodic pattern have a phase difference of 180 °, the mask layer 35 is regarded as a periodic pattern in which the ratio of the line width to the space width of the pitch P in the X-axis direction is 1: 1. be able to. Again, it is possible that only manage the etching time, readily form a resist image 34 ₁ of a width P / 2.

Next, the target layer 31 is etched using the periodic pattern of the mask layer 35 as a mask. After etching, as shown in FIG. 4 (H), corresponding to the periodic pattern of the mask layer 35 as a mask on the wafer W, an array of target portion 31 ₁ of the width P / 2 in the X-axis direction at a pitch P A pattern is obtained. Thereafter, the resist image 34 ₁ is peeled off from the wafer W by an ashing device (not shown), and then the hard mask pattern 32 _{1 shown} in FIG. Thus, as shown in FIG. 4 (J), the ratio of the target portion 31 ₁ of the width P / 2 formed by arranging the X-axis direction at a pitch P, a line width and a space width of 1: 1 L / S pattern is formed. In this case, when the pitch P is 64 nm, the target portion 31 ₁ of the width (line width) is 32 nm.

[Impurity diffusion, aluminum evaporated wiring processing]
In parallel with or subsequent to the analysis process, impurity diffusion to the etched wafer W, aluminum vapor deposition wiring process, film formation by the CVD apparatus 910, planarization by the CMP apparatus 930, oxidation / ion implantation apparatus 940 Ion implantation is performed as necessary. Thereby, the patterning process for the target layer 31 of the wafer W is completed.

  Next, the host 600 determines whether all the processes have been completed and all the patterns have been formed on the wafer W. If this determination is denied, the process returns to the film forming process, and if affirmed, the process proceeds to the next process. As described above, a series of patterning processes are repeatedly executed for the number of steps, whereby the device patterns are stacked on the wafer W to form semiconductor devices.

  After the repetition process is completed, the probing process and the repair process are executed in the device manufacturing processing apparatus group 900. When a defect is detected in the probing process, for example, a process of replacing with a redundant circuit is performed in the repair process. The analysis apparatus 500 can also send information such as the detected location where the overlay abnormality has occurred to an apparatus that performs the probing process and the repair process. In the inspection apparatus (not shown), the portion where the line width abnormality has occurred on the wafer W can be excluded from the processing target for the probing process and the repair process in units of chips. Thereafter, dicing processing, packaging processing, and bonding processing are executed, and a product chip is finally completed.

  In the first exposure process and the second exposure process in FIG. 3, the reticles R <b> 1 and R <b> 2 are thermally deformed by absorbing the illumination light IL, and a pattern image (projection) projected onto the wafer in accordance therewith. The image is distorted. Further, since the wafers are continuously exposed in units of lots (usually 25 or 50 for one lot) using the reticles R1 and R2, the reticles R1 and R2 are deformed (particularly expanded / contracted) each time the wafer is exposed. This increases the distortion of the projected image of the pattern.

  FIG. 5A shows the residual between the actual value of shot scaling X (X scaling) during lot processing and the predicted value before optimization, and FIG. 5B shows shot scaling Y ( The residual between the actual value of (Y scaling) and the predicted value before optimization is indicated by black circles (●). It can be seen that each time a wafer is exposed, the shot scaling residual increases. This is because sufficient overlay accuracy (positioning accuracy) cannot be obtained even when precise wafer alignment (for example, in-shot multi-point EGA type wafer alignment) that considers even shot deformation prior to wafer exposure is performed. Suggests that.

  In view of this point, the device manufacturing system 1000 according to this embodiment corrects a pattern overlay error (positioning error) caused by reticle deformation (particularly expansion and contraction) as described above every time a wafer is exposed. A lot processing sequence for continuously exposing one lot of wafers is employed.

  6 and 7 are flowcharts showing an outline of a processing algorithm executed by the host 600 in the device manufacturing system 1000 of this embodiment.

The lot processing sequence shown in this flowchart starts in response to an operator instruction to the host 600. In giving the instruction, the operator designates the details of the exposure process, that is, the lot to be exposed, the exposure apparatus to be used (in this case, the exposure apparatus 100), the two reticles R1 and R2 to be used, and the like. At the same time, the designated lot is carried into the exposure apparatus 100. One lot includes K wafers W _k (k = 1 to K, K = 25 as an example). In exposure apparatus 100, designated reticle R1 is loaded onto reticle stage RST.

[Step 502]
In the first step 502, a counter k indicating the number of the wafer in the lot is initialized to 1.

[Step 504]
In the next step 504, the wafer W _{k to be} exposed (here, the first wafer W ₁ ) is transferred to the measurement / inspection instrument 120. Wafer _Wk is transferred to measurement / inspection instrument 120 with a resist coated on the surface thereof by a coater / developer (C / D (not shown)) connected inline to exposure apparatus 100.

[Step 506]
In the next step 506, using the measurement test instrument 120, with respect to the wafer W _k to be exposed, it performs the pre-measurement for the first exposure using the reticle R1.

  In the preliminary measurement, the host 600 optimizes the alignment processing conditions. Here, the alignment processing conditions include alignment mark (wafer mark) design conditions, alignment mark detection conditions, processing conditions for processing alignment mark detection results, alignment error correction methods, and the like. The alignment mark design conditions include the number, arrangement, and shape of alignment marks. The detection conditions include the wavelength and intensity of the detection light when detecting the alignment mark by irradiating the detection light, the width and shape of the illumination area, the phase difference, and the like. The processing conditions include an EGA calculation model, which will be described later, and the correction method includes a correction model for correcting distortion of the projected image of the pattern accompanying the expansion and contraction of the reticle.

  In accordance with an instruction from the host 600, the measurement / inspection instrument 120 performs wafer alignment (in-shot multipoint EGA) on the wafer Wk for each of the above alignment processing conditions. The result of the wafer alignment is transmitted from the measurement / inspection instrument 120 to the host 600. The host 600 determines the optimum alignment processing condition using the received result. Note that an alignment process condition that gives the minimum alignment residual error described later is an optimum condition. The determined optimum alignment processing conditions are sent from the host 600 to the measurement / inspection instrument 120 and the exposure apparatus 100.

In FIG. 8 (A), a plurality of shots arranged on the wafer W _k are shown. As an example, the shots Sa1 to Sa6, Sb1 to Sb6, Sc1 to Sc6, and Sd1 to Sd6 are detected by the optimization of the above alignment processing conditions. As determined.

FIG. 9A shows an example of the arrangement of alignment marks M _ij (i, j = 1 to 8) formed in the sample shot. A total of 64 alignment marks M _ij (i, j = 1 to 8) are formed in the sample shot, 8 in the X-axis direction and 8 in the Y-axis direction. The interval between the alignment marks M _ij (i, j = 1 to 8) in the X-axis direction and the Y-axis direction is ΔD. As an example, the positions of these alignment marks M _ij (i, j = 1 to 8) are measured in advance measurement and post-measurement (multi-point EGA in a shot) by optimization of the above alignment processing conditions. It is determined as a target mark (to be detected).

In the pre-measurement, an alignment mark for wafer alignment (multi-shot EGA in a shot) is detected for the wafer W _k under the optimum alignment processing conditions determined above. The measurement / inspection instrument 120 includes alignment marks M _ij (i, j = 1 to 8) formed on the sample shots Sa1 to Sa6, Sb1 to Sb6, Sc1 to Sc6, and Sd1 to Sd6 shown in FIG. ) And the positions (X position, Y position) ξ _ij and ζ _ij of the alignment mark M _ij (i, j = 1 to 8) on the wafer coordinate system (or stage coordinate system). The measurement result is transferred from the measurement / inspection instrument 120 to the host 600.

The host 600 obtains shot scaling for the wafer W _k by using the measurement results ξ _ij and ζ _ij of the alignment mark M _ij (i, j = 1 to 8). Here, the alignment mark M _ij (i, j = 1 to 8) is formed together with the base pattern formed in the original process (layer). Therefore, the required shot scaling corresponds to the formation error of the base pattern formed in the original process (layer). In practice, the alignment mark M _ij (i, j = 1 to 8) is formed on the street that partitions the shot in which the base pattern is formed simultaneously with the base pattern formed in the original process (layer). However, here, for convenience of explanation, it is assumed that they are arranged in the shot.

As an example of a calculation model (EGA calculation model) for numerically processing the measurement results ξ _ij and ζ _ij by optimizing the previous alignment processing conditions, the following third-order shot array deformation calculation model (including shot linear components) Assume that (1a) and (1b) are determined.

ΔX = Cx ₃₀ Wx ³ + Cx ₂₁ Wx ² Wy + Cx ₁₂ WxWy ² + Cx ₀₃ Wy ³
+ Cx ₂₀ Wx ² + Cx ₁₁ WxWy + Cx ₀₂ Wy ²
+ Cx ₁₀ Wx + Cx ₀₁ Wy + Cx ₀₀ + Cx _SX Sx + Cx _SY Sy (1a)
ΔY = Cy ₃₀ Wx ³ + Cy ₂₁ Wx ² Wy + Cy ₁₂ WxWy ² + Cy ₀₃ Wy ³
+ Cy ₂₀ Wx ² + Cy ₁₁ WxWy + Cy ₀₂ Wy ²
+ Cy ₁₀ Wx + Cy ₀₁ Wy + Cy ₀₀ + Cy _SX Sx + Cy _SY Sy (1b)

In the above EGA calculation models (1a) and (1b), (Wx, Wy) and (Sx, Sy) are design positions of the alignment mark with respect to the wafer center and the shot center, respectively. Also, (Cx ₁₀ , Cy ₀₁ ) is wafer scaling, (Cx ₀₁ , Cy ₁₀ ) is wafer rotation, (Cx ₀₀ , Cy ₀₀ ) is wafer offset, (Cx _SX , Cy _SY ) is shot scaling, (Cx _SY , Cy _SX ) is a shot rotation. These coefficients are collectively referred to as EGA parameters. In correspondence with EGA parameters disclosed in US Pat. No. 6,876,946, etc., wafer orthogonality Ω = − (Cx ₀₁ + Cy ₁₀ ), wafer rotation Θ = Cy ₁₀ , shot orthogonality ω = − (Cx _SY + Cy _SX ), shot rotation θ = Cy _SX

The host 600 uses the measurement results ξ _ij and ζ _ij to minimize the alignment residual error ε = Σ _{ij = 1 to 8} ((ξ _ij −ΔX _ij ) ² + (ζ _ij −ΔY _ij ) ² ). Next, the least square method is applied to determine EGA parameters and coefficients included in the model. Here, ΔX _ij and ΔY _ij (i, j = 1 to 8) are corrections of alignment marks M _ij (i, j = 1 to 8) calculated by applying the calculation models (1a) and (1b). Amount. That is, ΔX and ΔY on the left side obtained by substituting the design position into (Wx, Wy) and (Sx, Sy) on the right side of the calculation models (1a) and (1b).

The host 600 stores (stores) in the storage device 140 the shot scaling (denoted as Cx _{SX, 1} , Cy _{SY, 1} ) for the wafer W _k obtained as described above. Thereby, preliminary measurement is completed.

[Step 508]
In the next step 508, the wafer W _k that has been pre-measured, is conveyed to the exposure apparatus 100 via a conveyance system (not shown). Wafer _{W k} that has been conveyed to the exposure apparatus 100 is loaded onto the wafer stage WST.

[Step 510]
In the next step 510, instruction is given to the exposure apparatus 100, performs wafer alignment (shot Uchida point EGA) on the wafer _{W k} to be exposed. Similar to the previous measurement, for example, it is assumed that the third-order shot array deformation calculation model (including the shot linear component) (1a) and (1b) is selected as the EGA calculation model.

  In addition, in the multi-point EGA measurement within a shot immediately before exposure, from the viewpoint of maintaining or improving the throughput, the number of shots smaller than the number 24 of sample shots that have been subjected to the above-described preliminary measurement is selected as the measurement target. For example, a part of 24 sample shots shown in FIG. 8A or 8 shots of sample shots Sa1, Sa2, Sb1, Sb2, Sc1, Sc2, Sd1, and Sd2 shown in FIG. 8B are measured. Selected as a target.

For the upper measurement target shot, fewer alignment marks than the number 64 of alignment marks shown in FIG. 9A are detected. For example, a part of 64 alignment marks, or 4 in the X-axis direction and 4 in the Y-axis direction shown in FIG. 9B, a total of 16 alignment marks m _ij (i, j = 1 to 4) are detected. The Here, the interval Δd in the X-axis direction and the Y-axis direction of the alignment mark m _ij (i, j = 1 to 4) is the alignment mark M _ij (i, j = 1 to 8) used in the previous preliminary measurement. Is larger than the interval ΔD (Δd> ΔD).

The main control unit 50, the shot Uchida point EGA measurement immediately before exposure, at determined optimum alignment process conditions in pre-measurement, with respect to the wafer _{W k,} sample shot Sa1, Sa2 shown in FIG. 8 (B), Sixteen alignment marks m _ij (i, j = 1 to 4) shown in FIG. 9B provided in Sb1, Sb2, Sc1, Sc2, Sd1, and Sd2 are detected, and the wafer coordinate system (or The positions (X position, Y position) ξ _ij and ζ _ij of the alignment mark m _ij (i, j = 1 to 4) on the stage coordinate system) are measured.

The main controller 50 applies the shot arrangement deformation calculation model (including the shot linear component) (1a) and (1b), and calculates the wafer component (shot) from the measurement results ξ _ij and ζ _ij (i, j = 1 to 4). Array error) and shot linear components are removed. The main controller 50 uses the measurement results ξ _ij and ζ _ij to minimize the alignment residual error ε = Σ _{ij = 1 to 4} ((ξ _ij −ΔX _ij ) ² + (ζ _ij −ΔY _ij ) ² ). As such, the least squares method is applied to determine EGA parameters and coefficients included in the model. ΔX _ij , ΔY _ij (i, j = 1 to 4) are correction amounts of the alignment mark m _ij (i, j = 1 to 4) converted by applying the calculation models (1a) and (1b). It is. That is, ΔX and ΔY on the left side obtained by substituting the design position into (Wx, Wy) and (Sx, Sy) on the right side of the calculation models (1a) and (1b).

The main controller 50 uses the determined EGA parameters and coefficients to remove the wafer components (shot alignment error) and the shot linear components from the measurement results ξ _ij and ζ _ij (i, j = 1 to 4), thereby remaining. An error (that is, an error in a shot) dξ _ij = ξ _ij −ΔX ′ _ij , dζ _ij = ζ _ij −ΔY ′ _ij (i, j = 1 to 4) is obtained. Here, ΔX ′ _ij and ΔY ′ _ij are correction amounts of the alignment mark m _ij (i, j = 1 to 4) calculated by applying the EGA calculation models (1a) and (1b).

  If a higher-order component is included in the wafer component (shot arrangement error), it is similarly removed. Details of handling higher order components are disclosed, for example, in US 2006/0040191.

[Step 512]
In the next step 512, the exposure apparatus 100, using the reticle R1, 1-time exposure process for the wafer _{W k} is performed. Here, main controller 50 calculates the position coordinates on the stage coordinate system of the shot to be processed on the wafer, using the EGA parameters and coefficients obtained in step 510. Main controller 50 drives lens element 27 via the imaging characteristic correction device and synchronizes reticle stage RST and wafer stage WST based on this calculation result and the results of reticle alignment and baseline measurement. The above-described scanning exposure is executed while finely correcting the driving. Then, the pattern (first pattern) of reticle R1 is sequentially transferred to all shots on wafer W. The details of driving the lens element for correcting the distortion of the projected image are described in, for example, US Pat. No. 5,117,255, and the details of the stage driving for correcting the distortion of the projected image are, for example, For example, it is disclosed in US Pat. No. 6,235,438. When the exposure for all shots on the wafer is completed, the process proceeds to step 514.

[Step 514]
In step 514, it is determined whether k <K is satisfied or not, and it is determined that exposure of all wafers W _k (k = 1 to K) in the lot is not completed. In this case, since k = 1, the determination here is affirmed, and the routine proceeds to the next Step 516. If k = K, steps 516 and 518 described later are skipped, and the process proceeds to step 520.

[Step 516]
In step 516, the exposed wafer W _k is transferred from the exposure apparatus 100 to the measurement / inspection instrument 120. However, the wafer _Wk is developed by a coater / developer (C / D (not shown)) connected in-line to the exposure apparatus 100, and is transported in a state where a resist pattern is formed.

[Step 518]
In the next step 518, post measurement is performed on the exposed wafer W _k using the measurement / inspection instrument 120. In the post-measurement, a deviation (overlay) between the alignment mark newly formed by the first exposure in step 512 and the mark of the original process layer is measured under the optimum alignment processing conditions determined in the pre-measurement. Here, the measurement / inspection instrument 120 is arranged as shown in FIG. 9 (A) assigned to each of the sample shots Sa1 to Sa6, Sb1 to Sb6, Sc1 to Sc6, Sd1 to Sd6 shown in FIG. 8 (A). Alignment marks M _ij (i, j = 1 to 8) are detected, and X and Y relative positions (X and Y positional deviations) Δξ _ij and Δζ _ij from the alignment marks already formed in the original process layer are measured. The measurement result is transferred from the measurement / inspection instrument 120 to the host 600.

The host 600 uses the measurement results Δξ _ij and Δζ _ij of the alignment mark M _ij (i, j = 1 to 8), and similarly uses the shot arrangement deformation calculation model (including the shot linear component) (1a), ( shot scaling? Cx _SX to wafer _{W k} using 1b), obtains the cy _SY. However, the shot scaling Cx _SX and Cy _SY are determined so that the alignment residual error ε = Σ _{ij = 1 to 8} ((Δξ _ij −ΔX _ij ) ² + (Δζ _ij −ΔY _ij ) ² ) is minimized. Determined shot scaled _Cx SX, the _{Cy SY,} pre-measurement, or, wafer alignment measurement (shot Uchida point EGA) shot scaling _Cx SX determined in order to distinguish it from _{Cy SY} etc., respectively? Cx _SX, 1, Indicated as ΔCy _{SY, 1} . The required shot scaling ΔCx _{SX, 1} , ΔCy _{SY, 1} is the difference between the formation error of the pattern formed in the original process layer and the formation error of the pattern formed in the current process layer, that is, the overlay error (original Corresponding to the pattern formed in the current process layer with respect to the pattern formed in the process layer.

The host 600 stores (stores) the shot scalings ΔCx _{SX, 1} and ΔCy _{SY, 1} obtained for the wafer W _k in the storage device 140. Thereby, the post measurement is completed.

[Step 520]
In the next step 520, the wafer W _k is transferred to the etching apparatus 920.

[Step 522]
In the next step 522, the first resist slimming process and the subsequent etching process are performed in the etching apparatus 920. Thereafter, the resist layer is peeled off from the wafer W by an ashing device (not shown). The details of these processes are as described above.

[Step 524]
In the next step 524, the wafer W _k is unloaded from the etching apparatus 920, thereby completing the first patterning in the double process method (double patterning method).

[Step 534]
In the next step 534, the wafer W _k that has undergone the _first patterning (here, the first wafer W ₁ ) is transferred to the measurement / inspection instrument 120. On the surface of the wafer W _k, by the coater developer (C / D (not shown)) is coated with a resist.

[Step 536]
In the next step 536, using the measurement test instrument 120, with respect to the wafer W _k, pre-measurement for the second exposure using the reticle R2 is performed. The details are the same as the preliminary measurement for the first exposure in step 506. That is, the detection of the alignment mark on the wafer W _k is performed, the shot scaling _{Cx SX, 2, Cy SY,} 2 to the wafer W _k is determined from the detection result is recorded in the storage device 140.

[Step 538]
In the next step 538, the pre-measured wafer _Wk is transferred to the exposure apparatus 100 via a transfer system (not shown). Wafer _{W k} that has been conveyed to the exposure apparatus 100 is loaded onto the wafer stage WST.

[Step 540]
In the next step 540, the exposure apparatus 100, wafer alignment of wafer _{W k} (shot Uchida point EGA) is performed. Details are the same as the wafer alignment in step 510. Accordingly, the coefficient included in the EGA parameters and the model for the wafer W _k is determined.

[Step 542]
In the next step 542, the exposure apparatus 100, by using the reticle R2, 2-time exposure process for the wafer _{W k} is performed. The details are the same as the first exposure process in step 542. Main controller 50 uses the EGA parameters and coefficients obtained in step 542 to calculate position coordinates on the stage coordinate system of the shot to be processed on the wafer. Main controller 50 drives lens element 27 via the imaging characteristic correction device and synchronizes reticle stage RST and wafer stage WST based on this calculation result and the results of reticle alignment and baseline measurement. The above-described scanning exposure is executed while finely correcting the driving. Then, the pattern (second pattern) of reticle R2 is sequentially transferred to all shots on wafer W. When the exposure for all shots on the wafer is completed, the process proceeds to step 544.

[Step 544]
In step 544, it is determined whether or not the exposure of all wafers W _k (k = 1 to K) in the lot is not completed by determining whether or not k <K is satisfied. In this case, since k = 1, the determination here is affirmed, and the routine proceeds to the next Step 546. When k = K, steps 546 and 548 described later are skipped and the process proceeds to step 550.

[Step 546]
In step 546, the exposed wafer W _k is transferred from the exposure apparatus 100 to the measurement / inspection instrument 120. However, the wafer _Wk is developed by a coater / developer (C / D (not shown)) connected in-line to the exposure apparatus 100, and is transported in a state where a resist pattern is formed.

[Step 548]
In the next step 548, post measurement is performed on the exposed wafer W _k using the measurement / inspection instrument 120. Details are the same as the post-measurement in step 518. That is, a deviation (superposition) between the alignment mark newly formed by the second exposure in step 542 and the mark of the original process layer is measured. From the measurement result, shot scalings ΔCx _{SX, 2} and ΔCy _{SY, 2} for the wafer W _k are obtained and recorded in the storage device 140.

[Step 550]
In the next step 550, the wafer W _k is transferred to the etching apparatus 920.

[Step 552]
In the next step 552, the etching apparatus 920 performs the second resist slimming process and the subsequent etching process. Thereafter, the resist layer is peeled off from the wafer W by an ashing device (not shown). The details of these processes are as described above.

[Step 554]
In the next step 554, the wafer W _k is unloaded from the etching apparatus 920. Thereby, the second patterning in the double process method (double patterning method) is completed.

[Step 560]
In step 560, it is determined whether k <K is satisfied or not, whereby it is determined that exposure of all wafers W _k (k = 1 to K) in the lot is not completed. In this case, since k = 1, the determination here is affirmed, and the routine proceeds to the next Step 562.

[Step 562]
In the next step 562, the shot scaling ΔCx _{SX, h} , ΔCy _{SY, h} (h = 1, 2) obtained in the subsequent measurement (steps 518 and 548), that is, the base pattern formed in the original process (layer) It is determined whether or not the overlay error between the first and second patterns formed in the current process (layer) exceeds a predetermined threshold value. If the judgment is affirmative, that overlay if the error exceeds the threshold value, the reticle R1, R2 is elastic (thermal expansion), and thereby the image of the pattern of the reticle R1, R2 to be transferred to the wafer W _k is deformed It can be determined that In this case, the routine proceeds to a subroutine for reticle expansion / contraction correction and optimization of the alignment processing conditions in step 564. On the other hand, if this determination is negative, that is, if the overlay error does not exceed the threshold value, step 564 is skipped and the process proceeds to step 566.

[Step 564]
The processing of step (subroutine) 564 is performed by the analysis apparatus 500 under the instruction of the host 600. In step (a subroutine) 564, first, in step 602 of FIG. 10, each wafer _{W k,} expansion amount E _X of the actual reticle Rh (h = 1, 2) _{(net), k, h = E MX} , k _{, h} + E _{LX, k, h} + B _{X, k, h} −S _{SX, k, h} , E _{Y, k, h} = E _{MY, k, h} + E _{LY, k, h} + B _{Y, k, h} −S _{SY , k, h} . Here, E _{MX, k, h} and E _{MY, k, h} are the formation errors of the pattern formed in the current process (layer), and these are prior to the h-th exposure for each wafer W _k. Shot scaling Cx _{SX, k, h} , Cy _{SY, k, h} obtained in the measurement (steps 506, 536) and shot scaling ΔCx _{SX, k, h} , ΔCy _SY obtained in the subsequent measurement (steps 518, 548) _{, k, h} and (E _{MX, k, h} = Cx _{SX, k, h} + ΔCx _{SX, k, h} , E _{MY, k, h} = Cx _{SY, k, h} + ΔCx _{SY, k, h} ).

The formation errors E _{MX, k, h} and E _{MY, k, h} of the pattern formed in the current process (layer) are shots obtained in the alignment measurement (multi-point EGA within shot) (steps 510 and 540). It can also be obtained from the sum of the scaling Cx _{SX, k, h} , Cy _{SY, k, h} and the shot scaling ΔCx _{SX, k, h} , ΔCy _{SY, k, h} obtained in the subsequent measurement (steps 518, 548). (E _{MX, k, h} = Cx _{SX, k, h} + ΔCx _{SX, k, h} , E _{MY, k, h} = Cx _{SY, k, h} + ΔCx _{SY, k, h} )

In the above equation, E _{LX, k, h} , E _{LY, k, h} are lens control trace amounts (amounts corrected by the imaging characteristic correction device), B _{X, k, h} , B _{Y, k, h} is a magnification correction amount by the baseline measurement, and S _{SX, k, h} , S _{SY, k, h} is a predetermined magnification offset set in advance. These correction amounts are given from the exposure history of the wafer W _k sent from the main controller 50.

In the next step 603, an exposure power P _{k, h} absorbed by the reticle Rh by h (= 1, 2) -th exposure of the wafer W _k is _obtained using the following equation.

上式（２）において、Ｅ_Lk,hはウエハＷ_kにおけるレンズ制御トレース量、Ｅ_L,k-1,m,hは先に露光されたウエハＷ_k-1におけるレンズ制御トレース量、ΔｔはウエハＷ_ｋ−１の露光とウエハＷ_ｋの露光との時間間隔、Ｔ_m,hとＳ_m,hはそれぞれレチクルＲｈ（ｈ＝１，２）の伸縮の時定数と飽和値である。

In the above equation (2), E _{Lk, h} is the lens control trace amount on the wafer W _k , E _{L, k−1, m, h} is the lens control trace amount on the previously exposed wafer W _k−1 , and Δt is The time interval between the exposure of the wafer W _{k-1 and} the exposure of the wafer W _k , T _{m, h} and S _{m, h} are the time constant and saturation value of the reticle Rh (h = 1, 2), respectively.

In the next step 604, expansion volume E _{X0, k} reticle Rh (h = 1,2) at the time of exposure of the wafer _{W k, h, E Y0,} k, and _h, it is calculated from the following reticle telescopic correction model.

ここで、Ｅ_X0,k-1,m,hは、ウエハＷ_k-1におけるＸ方向のレチクル伸縮量、ΔｔはウエハＷ_ｋ−１の露光とウエハＷ_ｋの露光との時間間隔、Ｐ_k,hはウエハＷ_ｋのｈ回目の露光によりレチクルＲｈに吸収される露光パワー、Ｔ_Xm,hとＳ_Xm,hはそれぞれレチクルＲｈのＸ方向の伸縮の時定数と飽和値である。

_{Here, E X0, k-1,} m, h is a reticle expansion amount in the X direction of the wafer W _k-1, Δt is the time interval between the exposure of the wafer W _k-1 of the exposure and the wafer W _k, P _{k , h} is h-th exposure power absorbed by the reticle Rh by exposure of the wafer W _k, T _{Xm, h} and S _{Xm, h} is a constant and the saturation value when the expansion and contraction of the X direction of the reticle Rh respectively.

ここで、Ｅ_Y0,k-1,m,hは、ウエハＷ_k-1におけるＹ方向のレチクル伸縮量、ΔｔはウエハＷ_ｋ−１の露光とウエハＷ_ｋの露光との時間間隔、Ｐ_k,hはウエハＷ_ｋのｈ回目の露光処理によりレチクルＲｈに吸収される露光パワー、Ｔ_Ym,hとＳ_Ym,hはそれぞれレチクルＲｈのＹ方向の伸縮の時定数と飽和値である。なお、ここでは、レチクルＲｈの収縮と伸長の時定数は同じ値を用いている。

_{Here, E Y0, k-1,} m, h is a reticle expansion amount in the Y direction in the wafer W _k-1, Δt is the time interval between the exposure of the wafer W _k-1 of the exposure and the wafer W _k, P _{k , h} is the exposure power absorbed by the reticle Rh by the h-th exposure process of the wafer W _k , and T _{Ym, h} and S _{Ym, h} are the time constant and the saturation value of the expansion and contraction of the reticle Rh in the Y direction, respectively. Here, the same value is used for the time constant of contraction and extension of reticle Rh.

  The first term in parentheses on the right side of the equations (3) and (4) is the contraction of the reticle Rh (h = 1, 2) due to heat release, and the second term is the reticle Rh (h = 1, 2) due to heat absorption. Represents the expansion of Note that the amount of expansion / contraction of reticle Rh (h = 1, 2) is obtained from the sum of the components of m, assuming that a plurality of mechanisms contribute to the expansion / contraction of reticle Rh (h = 1, 2). In this embodiment, m = 3 is selected empirically.

Next, in step 608, the X-direction expansion / contraction amount E _{X0, k, h} and the Y-direction expansion / contraction amount E _{Y0, k, h of} the reticle Rh (h = 1, 2) obtained above are respectively determined in advance. The actual expansion / contraction amount E _{X, k, h in the} Y direction and the expansion amount E _{Y in the} Y direction of the reticle Rh (h = 1, 2) obtained from the measurement results of the prior measurement (or alignment measurement) and the subsequent measurement. _{, k, h} to determine whether or not there is a significant deviation. If this determination is affirmative, that is, if the difference is greater than a predetermined threshold value, the process proceeds to step 610 to optimize the reticle expansion / contraction correction parameters (time constant and saturation value).

Specifically, with respect to the reticle expansion / contraction in the X direction, the actual expansion / contraction amount E _{X0, k−1, m} for the wafer W _{k−1 with} respect to the h-th exposure using the reticle Rh (h = 1, 2). _{, h,} exposure power absorbed by an exposure process of the wafer W _k to the reticle Rh P _{k, h,} and the wafer W _k-1 of the exposure and the wafer W _k time intervals Δt the reticle expansion correction model the exposure of (3) by substituting in, reticle expansion and contraction amount at the time of exposure of the wafer W _k E _{X0, k,} to calculate the _h. This is sequentially calculated for the wafers W _{1 to} W _{k ,} and the residual ΔE _{X, k, h} = E _{X0, k, h} between E _{X0, k, h} and the actual reticle expansion / contraction amount E _{X , k, h} A statistical sum of −E _{X, k, h} , for example, square sum Ex _k = Σ _{k = 1 to k} w ₁ ΔEX _{, k, 1} ² + w ₂ ΔEX _{, k, 2} ² + w ₃ (ΔEX _{, k, 1} −ΔE _{X, k, 2} ) Applying the method of least squares so that ² is minimized, T _{Xm, h} and S _{Xm, h in} the correction model (3) for the reticle Rh (h = 1, 2) To optimize. Note that w ₁ , w ₂ , and w ₃ are arbitrarily determined weights.

As for the reticle expansion / contraction in the Y direction, the actual expansion / contraction amount E _{Y0, k−1} for the wafer W _{k−1 is obtained} for the h-th exposure using the reticle Rh (h = 1, 2) in the same manner as above _{. m, h,} exposure power absorbed by an exposure process of the wafer W _k to the reticle Rh P _{k, h,} and the wafer W _k-1 of the exposure and the wafer W _k time intervals Δt the reticle expansion correction model the exposure of (4 ) To calculate the reticle expansion / contraction amount E _{Y0, k, h} when the wafer W _k is exposed. This is sequentially calculated for the wafers W _{1 to} W _{k ,} and the residual ΔE _{Y, k, h} = E _{Y0, k, h} between E _{Y0, k, h} and the actual reticle expansion / contraction amount E _{Y , k, h} -E _{Y, k, h} statistical sum, for example, square sum Ey _k = Σ _{k = 1 to k} w ₁ ΔE _{Y, k, 1} ² + w ₂ ΔE _{Y, k, 2} ² + w ₃ (ΔE _{Y, k, 1} −ΔE _{Y, k, 2} ) Applying the least square method so that ² is minimized, T _{Ym, h} and S _{Ym, h in} the correction model (4) for reticle Rh (h = 1, 2) To optimize. Note that w ₁ , w ₂ , and w ₃ are arbitrarily determined weights.

FIG. 5 (A) shows the actual expansion / contraction amount EX _{, k, h} during the lot processing and the predicted expansion / contraction amount obtained from the reticle expansion / contraction correction model (3) before and after optimization (hereinafter appropriately predicted). A typical example of the difference (residual difference) from E _{x0, k, h} (also referred to as the amount of expansion / contraction) is shown for in-lot wafers W _k (k = 1 to 25). FIG. 5B shows the predicted expansion / contraction amount (predicted expansion / contraction amount) E obtained from the actual expansion / contraction amount E _{Y, k, h} during lot processing and the reticle expansion / contraction correction model (4) before and after optimization. typical examples of _{Y0, k,} the difference between _h (residual) is shown for the lot in the wafer W _{k (k} = 1~25).

  By optimizing the reticle expansion / contraction correction parameters (saturation value and time constant) as described above, the expansion / contraction correction models (3) and (4) of the reticle Rh (h = 1, 2) are optimized, and pattern overlap is performed. It can be seen that the alignment error is improved. Here, the reticle expansion / contraction correction model is optimized for each wafer in the lot, but it is desirable in terms of overlay accuracy to optimize for each wafer shot.

In the next step 612, the predicted expansion / contraction amounts E _{X0, k, h} and E _{Y0, k, h} of the reticle Rh (h = 1, 2) are obtained using the reticle expansion / contraction correction models (3) and (4). The result is sent to the main controller 50.

In the next step 613, the expansion / contraction amount E _{X0, k, h} obtained from the reticle expansion / contraction correction model (3) before optimization of the reticle Rh (h = 1, 2) and the reticle expansion / contraction correction model (3) after optimization. obtained from expansion and contraction amount E _{X0, k,} the difference in _h, for each wafer W _k, is reflected in the X-direction overlay measurement result in the exposure of the h-th. Similarly, it is obtained from the expansion / contraction amount E _{Y0, k, h} obtained from the reticle expansion / contraction correction model (4) before optimization of the reticle Rh (h = 1, 2) and the reticle expansion / contraction correction model (4) after optimization. expansion amount E _{Y0, k,} the difference in _h, for each wafer W _k, is reflected in the Y-direction overlay measurement result in the exposure of the h-th.

  In the next step 614, it is determined as a result of the above whether the pattern overlay error is larger than a given threshold value. If larger, it is determined that there is a major factor of overlay error other than the reticle expansion / contraction correction, and the process proceeds to step 616 to further optimize the alignment processing conditions. Details thereof are omitted. When the optimization of the alignment processing conditions is completed, the subroutine processing at step 564 is terminated, and the processing returns to step 566 of the main routine.

  On the other hand, if the determination in step 614 is negative, that is, if the pattern overlay error is smaller than the given threshold, step 616 is skipped, the processing of the subroutine in step 564 is terminated, and step 566 of the main routine is entered. Return.

  If the determination in step 608 is negative, that is, if the difference is equal to or smaller than a predetermined threshold value, the process proceeds to step 616 to optimize the alignment processing conditions.

[Step 566]
In step 566, the value of the counter k is incremented by 1 (k ← k + 1), and then the process returns to step 504. Thereafter, the processing in step 504 and subsequent steps is repeated until the determination in step 560 is denied.

When the above steps are repeated and exposure of all wafers W _k (k = 1 to K) in the lot is completed, the determination in step 560 is denied and the series of processing (lot processing sequence) of this routine is completed. .

  As described above in detail, according to the device manufacturing system 1000 according to the present embodiment, the reticle expansion / contraction correction models (3) and (4) describing the expansion / contraction of the two reticles R1 and R2 used in the double patterning method. ), The parameters related to the amount of expansion / contraction of the reticle (reticle expansion / contraction correction parameters (time constant and saturation value)) are optimized, so that the expansion / contraction correction of the reticles R1 and R2 is optimized, resulting in improved pattern alignment accuracy. It becomes possible to make it. In addition, the reticle expansion / contraction correction models (3) and (4) in which the reticle expansion / contraction correction parameters are optimized are used to align the patterns of the reticles R1 and R2 with the target layer of the next wafer to be exposed. As a result, the target pattern can be accurately aligned with the target layer on the wafer without being affected by the thermal expansion / contraction correction error of the reticle.

In the present embodiment, in the optimization (step 610) of the reticle expansion / contraction correction parameter (time constant and saturation value) in the lot processing sequence, the reticle Rh () is calculated using a statistical sum other than the square sums Ex _k and Ey _k. It is also possible to optimize T _{Xm, h} , T _{Ym, h} , S _{Xm, h} , S _{Ym, h} in correction models (3) and (4) for h = 1, 2).

For example, the statistical sums Σ _{k = 1 to k} ΔE _{X, k, 2} ² and Σ _{k = 1 to k} ΔE _{Y for} the residuals E _{X, k, 2} and E _{Y, k, 2} in the second patterning correction. _{, k, 2} ² confirms that less than a predetermined threshold, the difference Delta] E X reticle expansion correction residual between first patterning and second _{patterning, k, 1 -ΔE X, k} , 2, ΔE Y, k _{, 1} −ΔE _{Y, k, 2} Σk _{= 1 to k} (ΔE _{X, k, 1} −ΔE _{X, k, 2} ) ² , Σ _{k = 1 to k} (ΔE _{Y, k, 1} − ΔE _{Y, k, 2} ) ² is used to optimize T _{Xm, 2} , S _{Xm, 2 in} correction model (3) and T _{Ym, 2} , S _{Ym, 2} in correction model (4) for reticle R2 Turn into. Thereby, the alignment error due to the expansion / contraction of the reticle R1 is reflected in the expansion / contraction correction for the reticle R2, and the expansion / contraction correction of the reticle R1 is effectively performed by performing the expansion / contraction correction for the reticle R2. In this method, for example, in step 608, the predicted value (expanded expansion / contraction amount) E _{X0, k, 1} , E _{Y0, k, 1} of the reticle R1 obtained from the reticle expansion / contraction correction model is obtained by the pre-measurement and the post-measurement. The actual expansion / contraction amount (measured expansion / contraction amount) E _{X, k, 1,,} E _{Y, k, 1} obtained from the measurement result is largely contradictory, but the predicted expansion / contraction amount E _{X0, k, 2} , E _{Y0 of the} reticle R2 _{, k, 2} can be applied when it is determined that there is no significant contradiction with the measured expansion / contraction amounts EX _{, k, 2, EY, k, 2} .

Alternatively, the statistical sums Σ _{k = 1 to k} ΔE _{X, k, 1} ² and Σ _{k = 1 to k} ΔE _{Y for} the residuals E _{X, k, 1} and E _{Y, k, 1} of the reticle expansion / contraction correction in the first patterning. _{, k, 1} ² confirms that less than a predetermined threshold, first patterning and statistical sum sigma _{k = 1 to k} for differences in the reticle expansion correction residual between the second patterned _{(ΔE X, k, 1} - ΔE _{X, k, 2} ) ² , Σ _{k = 1 to k} (ΔE _{Y, k, 1} −ΔE _{Y, k, 2} ) ² is used to correct T _{Xm, 1} in the correction model (3) for reticle R1. S _{Xm, 1} and T _{Ym, 1} and S _{Ym, 1} in the correction model (4) are optimized. Thereby, the alignment error due to the expansion / contraction of the reticle R2 is reflected in the expansion / contraction correction for the reticle R1, and the expansion / contraction correction of the reticle R2 is effectively performed by performing the expansion / contraction correction for the reticle R1. In this method, for example, in step 608, the predicted expansion / contraction amount E _{X0, k, 1} , E _{Y0, k, 1} of the reticle R1 is largely inconsistent with the actually measured expansion / contraction amount E _{X, k, 1,,} E _{Y, k, 1.} Not applicable, but is applied when it is judged that the predicted expansion / contraction amount E _{X0, k, 2} , E _{Y0, k, 2} of reticle R2 is largely inconsistent with the actual expansion / contraction amount E _{X, k, 2,,} E _{Y, k, 2} it can.

In addition, for example, by appropriately determining the weights w ₁ , w ₂ , and w ₃ , the reticle R1 expansion / contraction correction (corresponding to the residual reticle expansion correction in the first patterning) and the reticle R2 expansion / contraction correction (reticle expansion / contraction in the second patterning) Correction model), correction of the displacement of the reticle R1, R2 expansion / contraction deviation (corresponding to the difference in reticle expansion correction residual between the first patterning and second patterning), or any combination of these Can also be optimized.

  In the above embodiment, the sum of squares is used as the statistical sum, but instead of this, an average of the sum of squares, a standard deviation, an absolute value sum, or an average of the absolute value sums can be used.

  In the above-described embodiment, the reticle expansion / contraction correction and the pre-measurement and post-measurement are performed each time each wafer in the lot is exposed. However, the present invention is not limited to this. For example, the change in reticle expansion / contraction is gradual. In some cases, reticle expansion / contraction correction and pre-measurement and post-measurement therefor may be performed each time a predetermined number (multiple) of wafers are exposed. In addition to this, the actual expansion / contraction of the reticle R obtained from the measurement results of the pre-measurement and the post-measurement for determining whether the reticle expansion / contraction correction is performed for each wafer or the reticle expansion / contraction correction is performed for each predetermined number of wafers. The residual threshold value between the amount and the predicted value of the amount of expansion / contraction obtained using the reticle expansion / contraction correction model may be determined.

  In addition, although only one measurement / inspection instrument 120 is introduced into the device manufacturing system 1000 of the above embodiment, a plurality of measurement / inspection instruments may be introduced. However, pre-measurement and post-measurement for one wafer are performed using the same measurement / inspection instrument.

  In the above-described embodiment, the wafer is in a lot. However, if the reticle expansion / contraction is not saturated in one lot, the reticle expansion / contraction correction, pre-measurement and post-measurement are performed for wafers in a plurality of lots. Also good.

  In the above embodiment, the shot scaling component is corrected. However, if the deformation is caused by the reticle thermal deformation, the shot shift component correction, the shot rotation component correction, the shot orthogonality component correction, The same can be applied to the correction of the higher-order deformation component in the next or higher shot. That is, reticle deformation correction model equations (3) and (4) describing the respective deformations of the two reticles used in the double patterning method for each component that changes with time due to thermal deformation of the reticle. Is calculated, the reticle deformation correction parameters (saturation value and time constant) are obtained, and are corrected during the exposure process.

  In the above embodiment, the lot processing sequence corresponding to the flowcharts of FIGS. 6, 7, and 10 is performed by the host 600. However, the present invention is not limited to this, and at least a part of the functions of the host 600 is performed. Of course, the main controller 50 of the exposure apparatus 100 and other controllers may be provided. Similarly, in the above embodiment, the processing of the subroutine 564 performed by the analysis device 500 may be performed by a computer other than the analysis device 500 such as the host 600 and the main control device 50.

  In the above-described embodiment, the double patterning method including a resist trimming process for forming a resist image having a desired line width (a line width less than the resolution limit of the exposure apparatus) and a desired pitch is described above. Although the case where the embodiment is applied has been described, the present invention is not limited to this, but is not limited to a double patterning method including a side wall coating process (Sidewall Process), a pitch splitting type without resist trimming, and other types of double patterning methods. In addition, the above embodiment can be preferably applied.

  In the present embodiment, the exposure apparatus 100 is a step-and-scan type exposure apparatus, but is not limited thereto, and may be a step-and-repeat type or other type of exposure apparatus. As represented by this, the various apparatuses are not limited to those types. Moreover, the said embodiment is applicable not only to a semiconductor manufacturing process but the manufacturing process of the display containing a liquid crystal display element etc. In addition to the process of transferring the device pattern onto the glass plate, the manufacturing process of the thin film magnetic head, and the manufacturing process of the imaging device (CCD, etc.), micromachine, organic EL, DNA chip, etc. Of course, the above embodiment can be applied to management.

  In the above embodiment, the analysis apparatus 500 is a computer, and the analysis function is realized by a program that causes the computer to execute the analysis function. Since this program is downloaded from the Internet or installed from a state recorded on an information recording medium such as a CD-ROM, the analysis function itself can be easily added, changed, or modified.

  In the above embodiment, the analysis apparatus 500 is a personal computer, for example. That is, the analysis processing in the analysis apparatus 500 is realized by executing an analysis program on a PC. As described above, the analysis program may be installable on the PC via the medium as described above, or may be downloaded to the PC via the Internet or the like. Of course, the analysis apparatus 500 may be configured by hardware.

  The mask expansion / contraction correction optimization method of the present invention is suitable for mask expansion / contraction correction optimization in double patterning. Further, the exposure method of the present invention is suitable for accurately forming a pattern on an object. The device manufacturing method and device manufacturing system of the present invention are suitable for manufacturing electronic devices.

  DESCRIPTION OF SYMBOLS 100 ... Exposure apparatus, 110 ... C / D, 120 ... Measurement inspection device, 500 ... Analysis apparatus, 900 ... Device manufacturing processing apparatus group, 1000 ... Device manufacturing system, W ... Wafer.

Claims (41)

When each of a plurality of objects is sequentially performed by superimposing the pattern on the target layer by superimposing the pattern on the target layer by performing lithography processes including exposure and development a plurality of times. A mask expansion / contraction correction optimization method for optimizing the expansion / contraction correction of the mask used in each of the first exposure and the second exposure,
Detecting a plurality of first marks formed together with a first pattern constituting a part of the target pattern on the target layer of one of the plurality of objects, and using the detection result, the first pattern; The first mask used for forming the first mask is obtained by calculating an expansion amount of the first mask, and a first residual between the expansion amount of the first mask and the predicted value of the expansion amount obtained from the first correction model describing the expansion amount is obtained. One step;
A plurality of second marks formed together with a second pattern constituting a part of the target pattern on the target layer is detected, and the expansion / contraction amount of the second mask used for forming the second pattern using the detection result A second step of obtaining a second residual between the expansion / contraction amount of the second mask and the predicted value of the expansion / contraction amount obtained from the second correction model describing the expansion / contraction amount;
At least one of the first and second correction models using a statistical sum of at least one of the first residual, the second residual, and the difference between the first and second residuals. A third step of optimizing parameters relating to the amount of expansion and contraction of the mask;
Mask expansion / contraction correction optimization method.   In the third step, the first and second correction models are calculated using a statistical sum of the first residual, the second residual, and the difference between the first and second residuals. The mask expansion / contraction correction optimization method according to claim 1, wherein a parameter related to an amount of expansion / contraction of the mask is optimized.   In the third step, a parameter relating to the expansion / contraction amount of the mask for the second correction model is obtained using a statistical sum of each of the second residual and the difference between the first and second residuals. The mask expansion / contraction correction optimizing method according to claim 1, which is optimized.   In the third step, a parameter relating to the amount of expansion / contraction of the mask for the first correction model is obtained using a statistical sum for each of the first residual and the difference between the first and second residuals. The mask expansion / contraction correction optimizing method according to claim 1, which is optimized. A plurality of partition regions are formed on the target layer of the one object, the first marks are formed together with the first pattern in each of the plurality of partition regions, and the first marks are formed together with the second pattern. 2 marks are formed,
5. The mask expansion / contraction correction optimization method according to claim 1, wherein in the first step, the plurality of first marks formed in at least a part of the plurality of partitioned regions are detected.   The mask expansion / contraction correction optimization method according to claim 5, wherein in the second step, the plurality of second marks formed in at least a part of the plurality of partitioned regions are detected.   The mask expansion / contraction according to any one of claims 1 to 6, wherein the statistical sum includes at least one of a sum of squares, an average of sum of squares, a standard deviation, an absolute value sum, and an average of absolute value sums. Correction optimization method.   The mask according to claim 7, wherein the statistical sum is obtained by adding a statistical weight to each of the difference between the first residual, the second residual, and the first and second residuals. Stretch correction optimization method.   Prior to the formation of the first pattern, detecting a plurality of marks formed on the object together with the base pattern, and obtaining an error in the formation position of the base pattern using a detection result of the plurality of marks. Furthermore, the mask expansion-contraction correction | amendment optimization method as described in any one of Claims 1-8 further included.   In the first step, an alignment error of the first pattern with respect to the base pattern is obtained using detection results of the plurality of first marks, and an error in the formation position of the base pattern and an alignment error of the first pattern The mask expansion / contraction correction optimization method according to claim 9, wherein the expansion / contraction amount of the first mask is obtained using.   In the second step, an alignment error of the second pattern with respect to the base pattern is obtained using detection results of the plurality of second marks, and an error in the formation position of the base pattern and an alignment error of the second pattern The mask expansion / contraction correction optimization method according to claim 9, wherein the expansion / contraction amount of the second mask is obtained using   In the third step, the accuracy of the first and second correction models is verified using the statistical sum, and based on the verification result, at least one of the first and second correction models is set to the expansion / contraction amount of the mask. The mask expansion / contraction correction optimization method according to claim 1, wherein the parameter is optimized. An exposure method for sequentially performing a process of superimposing a pattern on a target layer by performing lithography processes including exposure and development on the target layer a plurality of times so as to overlap each of a plurality of objects with an already formed base pattern. Because
Using the mask expansion / contraction correction optimization method according to any one of claims 1 to 12 to optimize a parameter related to an amount of expansion / contraction of the mask for at least one of the first and second correction models;
Aligning the first pattern with a target layer of another object of the plurality of objects using the first correction model, and transferring the first pattern onto the target layer;
Aligning the second pattern with the target layer of the other object using the second correction model, and transferring the second pattern onto the target layer;
An exposure method comprising:   When transferring the first and second patterns onto the other object, a plurality of marks formed in at least a part of a plurality of partitioned areas on the other object are detected, and the detection result is used. The exposure method according to claim 13, wherein the first and second patterns are aligned with each other.   When transferring the first and second patterns onto the different objects, the first and second patterns caused by magnification errors of the plurality of partitioned regions are respectively obtained using the first and second correction models. The exposure method according to claim 14, wherein an alignment error between two patterns is corrected.   When transferring the first and second patterns onto the different objects, the first and second correction models are used, respectively, to shift errors, rotation errors, orthogonality errors of the plurality of partitioned regions, The exposure method according to claim 14, wherein an alignment error of the first and second patterns caused by at least one of secondary and higher-order deformation errors is corrected. The first and second patterns are transferred onto the object via an optical system;
When the first and second patterns are transferred onto the other object, the first and second patterns are moved onto the other object by driving some optical elements included in the optical system. The exposure method according to claim 13, wherein alignment is performed. The first and second patterns are transferred onto the object by driving the mask on which the pattern is formed relative to the object,
14. When transferring the first and second patterns onto the different object, the first and second patterns are aligned on the different object by adjusting the relative driving, respectively. The exposure method as described in any one of -17.   By repeatedly optimizing a parameter related to the amount of expansion / contraction of the mask, transferring the first pattern, and transferring the first pattern, the target pattern is changed to a target layer of the plurality of objects. The exposure method according to claim 13, which is sequentially formed.   The exposure method according to claim 19, wherein the third step of optimizing the parameter related to the expansion / contraction amount of the mask is performed for each predetermined number of objects. Forming a pattern on a plurality of objects using the exposure method according to any one of claims 13 to 20;
Developing the object on which the pattern is formed;
A device manufacturing method including: Device manufacturing for each of a plurality of objects, in which a pattern is superimposed and formed on a target layer by multiple lithography processes including exposure and development, overlaid on an already formed base pattern. A system,
An exposure apparatus for transferring a pattern formed on a mask to the plurality of objects;
A measuring device having a function of detecting a mark formed on the object;
One or more computers including a host computer connected to the exposure apparatus and the measurement apparatus;
Any one of a plurality of computers including the exposure apparatus, the control computer for the measurement apparatus, and the one or more computers includes one of the target patterns on the target layer of one of the plurality of objects. A plurality of first marks formed together with the first pattern constituting the portion is detected using the measuring device, and the expansion / contraction amount of the first mask used for forming the first pattern is obtained using the detection result. A first residual between the expansion / contraction amount of the first mask and the predicted value of the expansion / contraction amount obtained from the first correction model describing the expansion / contraction amount is obtained, and a part of the target pattern is configured in the target layer. A plurality of second marks formed together with the second pattern are detected using the measuring device, and the amount of expansion / contraction of the second mask used for forming the second pattern is determined using the detection result. Therefore, a second residual between the expansion amount of the second mask and the predicted value of the expansion amount obtained from the second correction model describing the expansion amount is obtained, and the first residual and the second residual are obtained. Using a statistical sum of at least one of a difference and a difference between the first and second residuals, a parameter relating to a mask expansion / contraction amount is optimized for at least one of the first and second correction models. Device manufacturing system.   Any one of a plurality of computers uses the statistical sum of the first residual, the second residual, and the difference between the first and second residuals to perform the first and second corrections. 23. The device manufacturing system according to claim 22, wherein a parameter related to a mask expansion / contraction amount is optimized for the model.   Any of the plurality of computers uses a statistical sum for each of the second residual and the difference between the first and second residuals to relate to a mask expansion / contraction amount for the second correction model. 23. The device manufacturing system of claim 22, wherein the parameters are optimized.   Any of the plurality of computers uses a statistical sum for each of the first residual and the difference between the first and second residuals to relate to a mask expansion / contraction amount for the first correction model. 23. The device manufacturing system of claim 22, wherein the parameters are optimized. A plurality of partition regions are formed on the target layer of the one object, the first marks are formed together with the first pattern in each of the plurality of partition regions, and the first marks are formed together with the second pattern. 2 marks are formed,
The device manufacturing system according to any one of claims 22 to 25, wherein any one of the plurality of computers detects the plurality of first marks formed in at least a part of the plurality of partition regions.   27. The device manufacturing system according to claim 26, wherein any one of the plurality of computers detects the plurality of second marks formed in at least a part of the plurality of partition regions.   The device manufacturing system according to any one of claims 22 to 27, wherein the statistical sum includes at least one of a sum of squares, an average of sum of squares, a standard deviation, an absolute value sum, and an average of absolute value sums. .   29. The device of claim 28, wherein the statistical sum is obtained by adding a statistical weight to each of the first residual, the second residual, and the difference between the first and second residuals. Manufacturing system.   Prior to the formation of the first pattern, any of the plurality of computers detects a plurality of marks formed on the object together with the base pattern using the measuring device, and the detection results of the plurality of marks are detected. The device manufacturing system according to any one of claims 22 to 29, which is used to obtain an error in a formation position of the base pattern.   One of the plurality of computers obtains an alignment error of the first pattern with respect to the base pattern using detection results of the plurality of first marks, and determines an error in the formation position of the base pattern and the position of the first pattern The device manufacturing system according to claim 30, wherein an amount of expansion / contraction of the first mask is obtained using an alignment error.   One of the plurality of computers obtains an alignment error of the second pattern with respect to the base pattern using the detection results of the plurality of second marks, and determines an error in the formation position of the base pattern and the position of the second pattern 32. The device manufacturing system according to claim 30, wherein an amount of expansion / contraction of the second mask is obtained using an alignment error.   One of the plurality of computers verifies the accuracy of the first and second correction models using the statistical sum, and relates to a mask expansion / contraction amount for at least one of the first and second correction models according to the verification result. The device manufacturing system according to any one of claims 22 to 32, wherein the parameter is optimized.   The exposure apparatus aligns the first pattern with a target layer of another object of the plurality of objects using the first correction model, and transfers the first pattern onto the target layer; 34. A device according to any one of claims 22 to 33, wherein a second correction model is used to align the second pattern with a target layer of the other object and to transfer the second pattern onto the target layer. Manufacturing system.   The exposure apparatus detects a plurality of marks formed in at least a part of a plurality of partitioned regions on the other object when the first and second patterns are transferred onto the other object, The device manufacturing system according to claim 34, wherein the first and second patterns are aligned using the detection result.   36. The device manufacturing method according to claim 35, wherein the exposure apparatus corrects an alignment error of the first and second patterns caused by a magnification error of the plurality of partitioned regions using the first and second correction models. system.   The exposure apparatus uses the first and second correction models to at least one of a shift error, a rotation error, an orthogonality error, and a second or higher order deformation error of the plurality of partitioned regions. 36. The device manufacturing system according to claim 35, wherein the resulting alignment error of the first and second patterns is corrected.   The exposure apparatus includes an optical system that transfers the first and second patterns onto the object, and controls the first and second patterns by driving and controlling some optical elements included in the optical system. 38. The device manufacturing system according to any one of claims 34 to 37, wherein the device is aligned on the other object.   The exposure apparatus transfers the first and second patterns onto the object by relatively driving a mask on which the pattern is formed with respect to the object, and adjusting the relative drive to adjust the first pattern. The device manufacturing system according to any one of claims 34 to 38, wherein the second pattern is aligned on the other object.   Obtaining an alignment error of the first pattern; obtaining an alignment error of the second pattern; and optimizing a parameter relating to an expansion / contraction amount of the mask for at least one of the first and second correction models. 40. The target pattern is sequentially formed on the target layers of the plurality of objects by repeating and transferring the first and second patterns to the target layer of the different objects. The device manufacturing system according to claim 1.   Obtaining an alignment error of the first pattern; obtaining an alignment error of the second pattern; and optimizing a parameter relating to an expansion / contraction amount of the mask for at least one of the first and second correction models. 41. The device manufacturing system according to claim 40, which is performed for each predetermined number of objects.

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