JP6626273B2 - Exposure apparatus and article manufacturing method - Google Patents

Description

  The present invention relates to an exposure apparatus and an article manufacturing method.

  Exposure equipment is used to manufacture various devices including semiconductor devices such as ICs and LSIs, display devices such as liquid crystal panels, detection devices such as magnetic heads, imaging devices such as CCDs, and fine patterns used in micromechanics. I have. In a typical exposure apparatus of this kind, light from a light source forms a secondary light source as a substantial surface light source composed of a large number of light sources via a fly-eye lens or a micro fly-eye lens functioning as an optical integrator. I do. Light from the secondary light source is collected by the condenser lens and illuminates the mask or reticle on which the pattern is formed in a superimposed manner. The light passing through the mask forms an image on the substrate via the projection optical system. Thereby, the pattern of the mask is transferred to the substrate. However, in order to accurately transfer the pattern of the mask onto the substrate, it is essential to obtain a uniform amount of exposure light on the substrate.

  Therefore, a technique is proposed in which a variable blade (aperture) having an aperture width adjusting mechanism capable of adjusting the aperture width according to the uneven exposure light amount is arranged at a position optically conjugate with the mask to correct the uneven exposure light amount. (See Patent Documents 1 and 2). For example, Patent Literature 1 discloses a technique in which a position where the opening width does not change regardless of a change in the opening width is set as an immovable position, and an end of the exposure region substantially coincides with the immovable position. Japanese Patent Application Laid-Open No. H11-163873 discloses a long side defining a slit-shaped illumination area (exposure area) in order to correct a secondary or higher order component of uneven illuminance on the surface to be illuminated (uneven exposure light quantity on a substrate). A technique is disclosed in which one of them is formed into a curved shape containing a second or higher order component.

JP 2005-175040 A JP 2006-134932 A

  In recent years, in order to increase device mounting density, miniaturization of patterns transferred to a substrate has been required, and accordingly, errors in an exposure line width allowed for a pattern transferred to a substrate have become severe. ing. In order to reduce the exposure line width error, it is effective to make the amount of exposure light uniform on the substrate. Therefore, variable blades tend to have more aperture width adjustment mechanisms.

  Further, in order to make the amount of exposure light on the substrate even more uniform, it is necessary to change the variable blade into a complicated shape. In this case, in order to release the stress applied to the variable blade, a mechanism for releasing the stress is required at a connection portion between the variable blade and the opening width adjusting mechanism. Therefore, since the driving characteristics of the variable blade become very complicated, it becomes difficult to control the amount of exposure light over the entire exposure area. Furthermore, since the illuminance distribution of the light applied to the variable blade is a factor that reduces the uniformity of the exposure light amount on the substrate, the unevenness of the exposure light amount is corrected with higher accuracy in consideration of the driving characteristics of the variable blade. Technology is required.

  On the other hand, in order to improve the uniformity of the exposure line width, a technique of positively changing the exposure light amount on a substrate has been proposed. This technique corrects variations in exposure line width caused by process factors such as coating and development with the amount of exposure light, and is called exposure line width control. In a device manufacturing process, manufacturing conditions such as an exposure area are optimized for each device. Therefore, in order to improve the accuracy of the exposure line width control, the variable blade must be controlled optimally according to the device manufacturing conditions.

  The present invention has been made in view of such problems of the related art, and has an exemplary object to provide an exposure apparatus that is advantageous for adjusting the amount of light on a substrate.

In order to achieve the above object, an exposure apparatus according to one aspect of the present invention is an exposure apparatus that exposes a substrate, wherein an opening that shapes light from a light source and defines the shape of an exposure region on the substrate. A blade for forming a, including a plurality of driving units provided at a plurality of locations of the blade, an adjusting unit that adjusts the shape of the opening by driving the plurality of driving units, and the adjusting unit a control unit for controlling the said control unit includes a respective drive amounts of the plurality of driving portions, of the light incident on the position coordinates of the exposure area on the front Stories substrate through said opening based on the target exposure amount of the sensitivity matrix and the substrate showing the relationship between the exposure amount, the plurality of determining the respective driving amount of the driving unit to drive the plurality of drive unit based on the determined driving amount , The sensitivity matrix is one driving unit Characterized in that it comprises a coefficient indicating the sensitivity of the change in the exposure amount of light incident on each position coordinates for the drive as an element.

  Further objects and other aspects of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  According to the present invention, for example, it is possible to provide an exposure apparatus that is advantageous for adjusting the amount of light on a substrate.

FIG. 1 is a schematic diagram illustrating a configuration of an exposure apparatus as one aspect of the present invention. FIG. 2 is a plan view illustrating an example of a configuration of a slit section of the exposure apparatus illustrated in FIG. 1. 2 is a flowchart for explaining the operation of the exposure apparatus shown in FIG. FIG. 4 is a diagram illustrating a relationship between a driving amount of a driving unit of a slit unit and an exposure light amount on a substrate. FIG. 3 is a view showing the vicinity of an opening in a slit section shown in FIG. 2. FIG. 6 is a diagram illustrating a change in an exposure light amount at a position coordinate on a substrate with respect to driving of a driving unit of the slit unit illustrated in FIG. FIG. 6 is a diagram illustrating an example of the sensitivity of each position coordinate on the substrate to each of the driving units of the slit unit illustrated in FIG. 5. FIG. 3 is a diagram illustrating a relationship between a sensitivity matrix, a driving amount of each driving unit provided on a variable blade, and an adjustment amount of an exposure light amount at each position coordinate on a substrate. FIG. 3 is a view showing the vicinity of an opening in a slit section shown in FIG. 2. FIG. 3 is a diagram illustrating a relationship between a control gain matrix, a driving amount of each driving unit provided on a variable blade, and an adjustment amount of an exposure light amount at each position coordinate on a substrate. FIG. 4 is a diagram for explaining the control accuracy of the exposure light amount on the substrate.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In each of the drawings, the same members are denoted by the same reference numerals, and redundant description will be omitted. In each of the drawings, among the directions orthogonal to each other on the substrate surface, the scanning direction is the Y-axis direction, the other is the X-axis direction, and the direction orthogonal to the substrate surface is the Z-axis direction.

  FIG. 1 is a schematic diagram illustrating a configuration of an exposure apparatus 100 according to one aspect of the present invention. The exposure apparatus 100 is a lithography apparatus used for manufacturing a device such as a semiconductor element, a display element, a detection element, and an imaging element as articles. In this embodiment, the exposure apparatus 100 employs a step-and-scan method, and exposes (scans and exposes) a substrate using light (slit light) from a light source.

  The exposure apparatus 100 includes an illumination optical system 1, an alignment scope 2, a projection optical system 4, a substrate stage 16, a measurement unit 17, and a control unit 18, as shown in FIG. A mask (reticle) 3 as an original is arranged between the alignment scope 2 and the projection optical system 4. The substrate 15 is held on a substrate stage 16.

  The illumination optical system 1 is an optical system that illuminates the mask 3 having a pattern to be transferred to the substrate 15. The illumination optical system 1 includes, for example, a light source 5, a first condenser lens 6, a fly-eye lens 7, a plane mirror 10, a second condenser lens 8, a slit section 200, and an imaging optical system 9.

  The light source 5 includes, for example, a high-pressure mercury lamp and an elliptical mirror. The light emitted from the light source 5 passes through the first condenser lens 6 and the fly-eye lens 7, is reflected by the plane mirror 10 (bends the optical path), and has a function of adjusting the shape of the exposure area on the substrate 15. It is incident on 200.

  The slit section 200 is embodied as a field stop that regulates the shape of the illumination area on the mask 3, that is, the cross-sectional shape of the light illuminating the mask 3 so as to have, for example, a long arc shape in the X-axis direction. The slit part 200 is a Fourier transform surface of the fly-eye lens 7 and is arranged at a position optically conjugate with the mask 3.

  The imaging optical system 9 is arranged so as to illuminate the object plane of the projection optical system 4, that is, the mask 3, with the light that has passed through the slit section 200.

  Further, the illumination optical system 1 includes a change unit that changes the illumination condition for illuminating the mask 3. The illumination conditions include, for example, optical characteristics such as an incident angle distribution and an illuminance distribution of light illuminating the mask 3. As the changing unit, for example, a stop arranged on the exit surface of the fly-eye lens 7 can be used. By changing the aperture, it is possible to switch the illumination conditions such as annular illumination, large σ illumination, and small σ illumination. However, when the stop arranged on the exit surface of the fly-eye lens 7 is changed, the illuminance distribution of the light incident on the slit portion 200 changes, so that the unevenness of the exposure light amount on the substrate also changes. Therefore, when switching the illumination conditions, in addition to changing the stop arranged on the exit surface of the fly-eye lens 7, the slit unit 200 is controlled to optimize the unevenness of the exposure light amount on the substrate for each illumination condition. Need to be However, the changing unit that changes the lighting condition is not limited to the above-described configuration. For example, the stop arranged on the exit surface of the fly-eye lens 7 may be arranged on the incident surface side of the fly-eye lens 7.

  The alignment scope 2 simultaneously detects the alignment mark provided on the mask 3 and the alignment mark provided on the substrate 15 via the projection optical system 4.

  The projection optical system 4 is an optical system that projects an image of the pattern of the mask 3 illuminated by the illumination optical system 1 onto the substrate 15. The projection optical system 4 includes, for example, a first parallel flat plate 12a, a plane mirror 13, a concave mirror 11, a convex mirror 14, and a second parallel flat plate 12b. The mask 3 is arranged on the object plane of the projection optical system 4, and the substrate 15 is arranged on the image plane of the projection optical system 4. The projection optical system 4 is configured as any one of a 1 × optical system, an enlargement optical system, and a reduction optical system. In the present embodiment, the projection optical system 4 is configured as a 1 × optical system.

  The light passing through the mask 3 is divided into a first parallel flat plate 12a, a first surface 13a of the plane mirror 13, a first surface 11a of the concave mirror 11, a convex mirror 14, a second surface 11b of the concave mirror 11, a second surface 13b of the plane mirror 13, and The light enters the substrate 15 through the two parallel flat plates 12b in order. Thereby, the image of the pattern of the mask 3 illuminated by the illumination optical system 1 forms an image on the substrate.

  The measuring unit 17 includes, for example, a light amount sensor arranged on the substrate stage 16 and measures the light amount of light that passes through the slit unit 200 and enters each position coordinate on the substrate.

  The control unit 18 includes an arithmetic unit 18a and a storage unit 18b, and controls the entire exposure apparatus 100. In other words, the control unit 18 controls the operation of the exposure apparatus 100 by integrally controlling each unit of the exposure apparatus 100. Further, the control unit 18 functions as a setting unit that sets (determines) position coordinates and the like for controlling the amount of exposure light on the substrate, as described later. The calculation unit 18a performs a process related to control of the slit unit 200, for example, a calculation process of a command value for controlling the slit unit 200. The storage unit 18b stores parameters related to control of the slit unit 200, for example, a sensitivity matrix and a control gain matrix described later.

  FIG. 2 is a plan view showing an example of the configuration of the slit section 200. The slit unit 200 adjusts the shape of the exposure area on the substrate 15 to correct unevenness in the amount of exposure light generated in the exposure area when exposing the substrate 15 while scanning the mask 3 and the substrate 15. The slit section 200 includes, for example, a variable blade 201 and a fixed blade 202. The slit portion 200 controls the shape of the exposure area EE on the substrate 15 (that is, the amount of light that passes through the opening OP and enters the substrate 15) by the opening OP formed between the variable blade 201 and the fixed blade 202. Stipulate. The variable blade 201 cooperates with the fixed blade 202 to shape the light from the light source 5 to form the opening OP that defines the shape. In the present embodiment, since the variable blade 201 and the fixed blade 202 form an arc-shaped opening OP, the shape of the exposure region EE also becomes an arc shape. However, the shape of the exposure region EE is not limited to an arc shape, and may be, for example, a rectangular shape.

  Further, the slit section 200 includes a plurality of driving sections 203, 204, 205, 206, 207, 208 and 209 provided at a plurality of positions of the variable blade 201. Each of the plurality of driving units 203 to 209 pushes and pulls the variable blade 201 to locally change the width of the opening OP in the Y-axis direction. As described above, the slit unit 200 also has a function as an adjusting unit that adjusts the shape of the opening OP by driving the plurality of driving units 203 to 209.

  Each of the plurality of driving units 203 to 209 includes, for example, a rotational direction relief mechanism 210, an X-axis direction relief mechanism 211, a Z-axis direction relief mechanism 212, and an adjustment member 213. When the adjusting member 213 is pushed or pulled by an actuator or the like, the variable blade 201 moves via the rotational escape mechanism 210, the X-axis escape mechanism 211, and the Z-axis escape mechanism 212, and the Y-axis direction of the opening OP. Is locally changed. This makes it possible to adjust the shape of the exposure area EE on the substrate 15 and control the unevenness of the exposure light amount on the substrate. The actuator may be driven by, for example, an open loop control method based on the response characteristics of the actuator. A displacement sensor (not shown) is provided in each of the plurality of driving units 203 to 209 to measure a driving amount of each of the driving units 203 to 209, and a closed-loop control method is employed in which the actuator is driven until a predetermined driving amount or a driving position is reached. May be.

  Hereinafter, control of the slit unit 200 will be described. The slit section 200 is controlled by the control section 18 so that the light amount on the substrate of the light passing through the opening OP becomes the target light amount. FIGS. 3A and 3B are flowcharts for explaining the operation of the exposure apparatus 100 including the processing related to the control of the slit unit 200. The process related to the control of the slit unit 200 includes a sensitivity matrix obtaining process of obtaining a parameter related to the control of the slit unit 200, and a slit driving process of controlling the unevenness of the exposure light amount on the substrate by the slit unit 200.

  The sensitivity matrix acquisition processing will be described with reference to FIG. In S301, an illumination condition for acquiring a sensitivity matrix is set. In the present embodiment, setting (switching) of the illumination condition is performed by driving the aperture and the slit unit 200 (the driving units 203 to 209) arranged on the exit surface of the fly-eye lens 7.

  In step S302, each of the driving units 203 to 209 of the slit unit 200 is driven to the reference position according to the illumination conditions set in step S301. Here, the reference position is an initial position of the driving units 203 to 209 at the time of acquiring the sensitivity matrix, and is, for example, a position of the driving units 203 to 209 when the exposure light amount unevenness on the substrate is equal to or less than a threshold. It is.

  FIG. 4 is a diagram showing a relationship between the driving amounts of the driving units 203 to 209 and the exposure light amount on the substrate, wherein the driving amount [mm] is adopted on the horizontal axis, and the exposure light amount [%] is displayed on the vertical axis. Has adopted. In FIG. 4, the exposure light amount on the substrate when the driving amount of the driving units 203 to 209 is 0 [mm] is set to 100 [%]. When the driving units 203 to 209 are driven by +2 [mm], the exposure light amount on the substrate becomes 105 [%]. When the driving units 203 to 209 are driven by -2 [mm], the exposure light amount on the substrate becomes 97 [%]. [%]. The slit unit 200 adjusts the exposure light amount on the substrate by driving the driving units 203 to 209. The relationship between the driving amount of the driving units 203 to 209 and the exposure light amount on the substrate is shown in FIG. As shown, the characteristics are not always linear. Referring to FIG. 4, the linearity error increases as the driving range of the driving units 203 to 209 increases, that is, as the driving amount of the driving units 203 to 209 increases. To reduce the linearity error, it is effective to narrow the driving range of the driving units 203 to 209.

  Therefore, in the present embodiment, the reference positions of the driving units 203 to 209 can be changed for each lighting condition. Exposure line width control that positively changes the amount of exposure light on the substrate in order to improve the dimension of the pattern transferred to the substrate 15, so-called uniformity of the exposure line width, occurs due to process factors such as coating and development. The exposure line width variation is corrected by the exposure light amount. Therefore, in the exposure line width control, an error component generated due to a process factor is adjusted on the basis of the unevenness of the predetermined exposure light amount on the substrate. Therefore, the reference positions of the driving units 203 to 209 need to be appropriately set. Thus, the effect of the linearity error can be reduced to a minimum. Specifically, the drive position of the drive units 203 to 209 when the unevenness of the exposure light amount on the substrate is adjusted flat may be set as the reference position, or when the exposure line width becomes the most uniform in the device manufacturing process. The driving positions of the driving units 203 to 209 may be set as the reference positions.

  In S303, S304, and S305, the relationship between the driving amount of each of the driving units 203 to 209 and the amount of light that passes through the opening OP and is incident on each position coordinate of a region on the substrate corresponding to the opening OP is described. Obtain the sensitivity matrix shown. As will be described later, the sensitivity matrix is a coefficient indicating the sensitivity of a change in the amount of light incident on each position coordinate of the region on the substrate corresponding to the opening OP with respect to driving of one of the driving units 203 to 209. Is included as an element.

  FIG. 5 is a view showing the vicinity of the opening OP in the slit section 200 shown in FIG. The slit unit 200 includes seven driving units A1 to A7 (corresponding to the plurality of driving units 203 to 209) provided on the variable blade 201. M1 to M11 in the region on the substrate corresponding to the opening OP indicate position coordinates (measurement position of the exposure light amount) on the substrate at which the measurement unit 17 measures the exposure light amount. However, the number of driving units provided on the variable blade 201 and the measurement position of the exposure light amount are not limited to these. For example, the measurement position of the exposure light amount may be equal to or more than the number of the driving units provided on the variable blade 201, and may be 20 or 40 or more.

  In the present embodiment, the driving units A1 to A7 provided on the variable blade 201 are driven one by one (that is, for each axis), and the exposure light amount by the measuring unit 17 is measured for each of the position coordinates M1 to M11 on the substrate. Perform measurement. FIG. 6 is a diagram showing a change in the amount of exposure light at the position coordinates M1 on the substrate with respect to the driving of the driving unit A1. The vertical axis represents the amount of exposure light [%] at M1. In FIG. 6, when the driving amount of the driving unit A1 is 0 [mm], the exposure light amount at the position coordinate M1 on the substrate is set to 100 [%]. For example, the reference position of the driving unit A1 is set to +1.2 [mm], the driving unit A1 is driven by ± 0.8 mm around the reference position, and the position coordinates M1 on the substrate are set at each of the reference position and the two driving positions. The exposure light quantity at is measured. The exposure light amount at the position coordinate M1 measured in this manner, that is, the inclination of a straight line obtained from the three measurement data is determined by the sensitivity of the change in the light amount of the light incident on the position coordinate M1 with respect to the driving of the driving unit A1 (hereinafter, referred to as the sensitivity). This is referred to as “the sensitivity of the position coordinates to the drive unit”). In the present embodiment, the driving unit A1 is driven to three driving positions including the reference position. However, if the driving unit A1 is driven to at least two driving positions, the sensitivity of the position coordinates M1 to the driving unit A1 can be obtained. Is possible. In other words, for each of the driving units A1 to A7, the driving unit to be driven is driven to at least two driving positions, and at each of the two driving positions, the exposure light amount for each of the position coordinates M1 to 11 on the substrate is reduced. You only need to measure it. Further, two driving positions may be set in a predetermined range from the reference positions of the driving units A1 to A7, that is, in a range in which a linearity error can be tolerated.

  FIG. 7 is a diagram illustrating an example of the sensitivity (sensitivity characteristic) of each of the position coordinates M1 to M11 on the substrate with respect to each of the driving units A1 to A7. In FIG. 7, the horizontal coordinates indicate the position coordinates M1 to M11 on the substrate, and the vertical axes indicate the sensitivities of the position coordinates M1 to M11 on the substrate with respect to the driving units A1 to A7. Referring to FIG. 7, the slit section 200 allows the entire area of the variable blade 201 to have sensitivity to the driving units A1 to A7, thereby controlling the entire area of the variable blade 201.

  Returning to FIG. 3, in S303, one of the plurality of driving units provided on the variable blade 201 is driven. For example, as described above, the drive unit A1 to the drive unit A7 are sequentially driven to the reference position, the drive position of the reference position −0.8 [mm], and the drive position of the reference position +0.8 [mm]. . However, each time the driving units A1 to A7 are driven once, the process proceeds to S304, and the measurement unit 17 measures the position coordinates M1 to M11 on the substrate.

  In S304, as described above, the exposure light amount is measured at each of the position coordinates M1 to M11 on the substrate. However, the measurement of the exposure light amount does not necessarily need to be performed for all of the position coordinates M1 to M11 on the substrate. As shown in FIG. 7, as the position coordinates of the drive units A1 to A7 that are farther from the drive unit to be driven have lower sensitivity, the position coordinates that are more than a certain distance from the drive unit to be driven are , Its sensitivity can be ignored. Therefore, the measurement of the exposure light amount is performed in a range having an effective sensitivity to the drive unit to be driven among the position coordinates M1 to M11 on the substrate, that is, the light amount for the drive of one drive unit to be driven. It is possible to limit only to changing position coordinates. For example, referring to FIG. 7, when the drive target is the drive unit A4, the measurement unit 17 determines the five position coordinates M4, M5, M6, M7, and M8 of the position coordinates M1 to M11 on the substrate. The exposure light amount may be measured by the following method. Note that the sensitivity is set to 0 for the position coordinates M1, M2, M3, M9, M10, and M11 for which the exposure light amount is not measured. This makes it possible to reduce the time required for measuring the amount of exposure light, and to obtain a sensitivity matrix in a short time.

  In S <b> 305, it is determined whether the measurement unit 17 has measured the exposure light amount for all of the plurality of driving units provided on the variable blade 201. If the measurement unit 17 has not measured the amount of exposure light for all of the plurality of driving units provided on the variable blade 201, the process proceeds to S303 and drives the next driving unit (S303). The exposure light amount is measured (S304). On the other hand, if the exposure unit has measured the amount of exposure light for all of the plurality of driving units provided on the variable blade 201, the process proceeds to S306.

  In S306, a sensitivity matrix is obtained from the measurement result in S304, and the sensitivity matrix is stored in the storage unit 18b as a parameter related to control of the slit unit 200. As described above, the sensitivity matrix includes, as elements, a coefficient indicating the sensitivity of a change in the amount of light at each position coordinate on the substrate with respect to the driving of each driving unit provided on the variable blade 201. 8 is a matrix of the sensitivity characteristics shown in FIG.

  FIGS. 8A to 8C show the sensitivity matrix GA, the driving amount SA of each of the driving units A1 to A7 provided on the variable blade 201, and the exposure light amount at each of the position coordinates M1 to 11 on the substrate. FIG. 6 is a diagram showing a relationship between the adjustment amount PM and the adjustment amount PM. For example, the sensitivity matrix GA shown in FIG. 8A has an 11 × 7 coefficient including, as an element, a coefficient indicating the sensitivity of each of the 11 position coordinates M1 to M11 on the substrate with respect to each of the seven driving units A1 to A7. It is a matrix. Referring to FIG. 8A, the element ga3_2 of the sensitivity matrix GA indicates the sensitivity of the position coordinate M3 on the substrate with respect to the driving unit A2. The element sa2 of the driving amount SA indicates the driving amount of the driving unit A2, and the element pm2 of the adjustment amount PM of the exposure light amount indicates adjustment of the exposure light amount at the position coordinate M3 on the substrate. Therefore, the amount of change in the amount of exposure light at each of the position coordinates M1 to M11 (the entire area of the exposure area EE) on the substrate can be obtained by the product of the sensitivity matrix GA and the drive amount SA of each of the drive units A1 to A7. .

  In step S307, it is determined whether there is another illumination condition for which a sensitivity matrix should be obtained. If there is another illumination condition for which a sensitivity matrix should be obtained, the flow shifts to S301 to set another illumination condition for which a sensitivity matrix is to be obtained. On the other hand, if there is no other illumination condition for which the sensitivity matrix should be acquired, the sensitivity matrix acquisition processing ends.

  As described above, the sensitivity matrix is acquired using the slit unit 200 and the measurement unit 17 for each illumination condition set by the illumination optical system 1. Therefore, it is possible to correct the unevenness in the light amount distribution of the light from the illumination optical system 1 and the unevenness in the exposure light amount on the substrate due to the driving characteristics of the slit section 200 using the sensitivity matrix. Further, even when the unevenness of the light amount distribution of the light from the illumination optical system 1 greatly changes depending on the lighting condition, the unevenness of the exposure light amount on the substrate can be corrected using the sensitivity matrix. It becomes.

Next, the slit driving process will be described with reference to FIG. In S308, exposure parameters are set. The exposure parameters are important parameters that determine the operating conditions of each unit of the exposure apparatus 100, and can be obtained from the exposure conditions set by the user on the exposure apparatus 100. For example, one of the exposure conditions is an integrated exposure amount when exposing the substrate 15. Exposure parameters related to the integrated exposure amount include a scanning speed of the substrate stage 16 and an exposure light amount incident on the substrate 15. The exposure apparatus 100 calculates the scanning speed of the substrate stage 16 and the amount of exposure light from the following equation (1) in order to expose the substrate 15 based on the set integrated exposure amount.
Integrated exposure amount [J] = exposure light amount [mm · W] / scanning speed of substrate stage 16 [mm / sec] (1)
Further, the user can set an exposure line width correction parameter (set light amount) as the exposure condition. The exposure line width correction parameter is an exposure light amount or an adjustment amount of the exposure light amount that can be set for each position coordinate on the substrate. For example, in the manufacture of a device, the thickness of the resist applied to the substrate 15 is not always uniform. In such a case, the dimension of the pattern finally transferred to the substrate 15, that is, the uniformity of the exposure line width is impaired. Therefore, the exposure line width control for adjusting the exposure amount so as to offset the variation of the exposure line width for each position coordinate on the substrate is effective. Generally, the relationship between the exposure line width and the exposure amount can be expressed by the following equation (2).
Exposure line width [μm] = Exposure amount [J] × Exposure sensitivity [μm / J] (2)
The exposure sensitivity is a parameter determined by the physical properties of the resist applied to the substrate 15 and the wavelength of the exposure light, and is a constant coefficient unless the resist or the light source 5 is changed. Therefore, by determining the exposure sensitivity in advance, it becomes possible to adjust the exposure amount and control the exposure line width. The position coordinates on the substrate on which the exposure correction parameters have been set are used in later steps (S311 and S312).

  In the present embodiment, the exposure condition is set by the user, but is not limited to this. For example, a system may be constructed in which an exposure apparatus 100 used for device manufacture and an inspection apparatus for inspecting an exposure line width are connected via a network, and an exposure condition such as an exposure line width correction parameter is automatically fed back.

  In S309, the range of the exposure area on the substrate 15 in the X-axis direction is determined. In the exposure apparatus 100, the maximum exposure area is determined according to the size of the variable blade 201 or the illumination area determined by the illumination optical system 1. However, in manufacturing a device, the maximum exposure area is not necessarily used. Not exclusively. The exposure area required for manufacturing the device can be determined by the range of the pattern of the mask 3, but the pattern of the mask 3 is basically designed so that the productivity of the device is highest. Therefore, the optimum size of the exposure region differs depending on the device manufacturing and its process. In the present embodiment, the exposure area, specifically, the range of the exposure area on the substrate 15 in the X-axis direction is determined according to the set value set by the user. The range of the exposure area in the X-axis direction determined in S309 is used in a subsequent step (S310).

  In step S310, position coordinates (first position coordinates) for controlling the exposure light amount on the substrate and a target light amount at such position coordinates, for example, the exposure light amount or the adjustment amount of the exposure light amount are set (determined). For example, as shown in FIG. 9, the position coordinates on the substrate of the exposure line width correction parameter set in S308 (the position coordinates on which the exposure line width correction parameter is set) are the positions on the substrate where the exposure light amount is measured. Consider the case where the coordinates are the same as M2, M4, M6, M8 and M10. In S309, it is assumed that the range EE 'of the exposure area on the substrate 15 in the X-axis direction has been determined. However, it is necessary to set the position coordinates for controlling the amount of exposure light on the substrate to be equal to or more than the number of driving units provided on the variable blade 201. This is to satisfy a condition necessary for calculating a control gain matrix described later.

  Hereinafter, the position coordinates for controlling the exposure light amount on the substrate and the specific determination methods (1) to (3) for determining the exposure light amount or the adjustment amount of the exposure light amount at the position coordinates will be described.

Determination method (1):
In the determination method (1), position coordinates that are standardly set in the exposure apparatus 100, for example, position coordinates M1 to M11 on the substrate shown in FIG. . As described above, in the determination method (1), the same position coordinates are always used regardless of the position coordinates on the substrate of the exposure line width correction parameter set in S308. However, in this case, the position coordinates M1, M3, M5, M7, M9, and M11 on the substrate shown in FIG. 9, that is, the exposure line width correction parameter (setting It is necessary to obtain a target light amount for position coordinates for which the light amount is not set. In other words, for the position coordinates M2, M4, M6, M8 and M10 on the substrate, the target light amount can be obtained (determined) from the exposure line width correction parameter set by the user. On the other hand, for the position coordinates M1, M3, M5, M7, M9 and M11 on the substrate, a target light amount must be obtained. For example, the target light amounts for the position coordinates M1, M3, M5, M7, M9, and M11 on the substrate can be obtained by an interpolation process (such as various linear interpolation processes) using an exposure line width correction parameter set by a user. It is. For example, the target light amount at the position coordinate M3 may be an intermediate value between the exposure line width correction parameter set at the position coordinate M2 and the exposure line width correction parameter set at the position coordinate M4. Further, spline interpolation may be performed based on the exposure line width correction parameters set at the position coordinates M2, M4, M6, M8, and M10. In the determination method (1), the relationship between the sensitivity matrix GA, the driving amount SA of each of the driving units A1 to A7, and the adjustment amount PM of the exposure light amount at each of the position coordinates M1 to 11 on the substrate is shown in FIG. ).

Determination method (2):
In the determination method (2), position coordinates set by the user are used as position coordinates for controlling the amount of exposure light on the substrate. However, since the position coordinates for controlling the exposure light amount on the substrate need to be set to be equal to or more than the number of the drive units provided on the variable blade 201, if it is not satisfied, the exposure light amount on the substrate is controlled. The position coordinates to be set must be added (newly set). For example, in FIG. 9, the variable blade 201 is provided with seven driving units A1 to A7, but the position coordinates set as the position coordinates for controlling the exposure light amount are five position coordinates M2, M4, M6, Since it is M8 and M10, it is necessary to add two or more position coordinates. The position coordinates to be added as the position coordinates to control the exposure light amount can be arbitrarily set by the user, for example. Here, position coordinates M3 and M9 are added as position coordinates for controlling the amount of exposure light. In the determination method (2), a target light quantity at a position coordinate at which the exposure light quantity on the substrate is to be controlled is acquired from the exposure line width correction parameter. However, for the position coordinates M3 and M9 added as the position coordinates to control the exposure light amount, the target light amount must be obtained. As described in the determination method (1), the target light amounts of the position coordinates M3 and M9 can be obtained by, for example, an interpolation process using an exposure line width correction parameter. In the determination method (2), the sensitivity matrix GA, the driving amount SA of each of the driving units A1 to A7, and the adjustment amount of the exposure light amount at each of the position coordinates M2, M3, M4, M6, M8, M9, and M10 on the substrate. The relationship with PM is as shown in FIG.

Determination method (3):
In the determination method (3), the position coordinates for controlling the amount of exposure light on the substrate are basically determined by the same process as the determination method (1). Therefore, in the determination method (3), the same position coordinates are always used regardless of the position coordinates on the substrate of the exposure line width correction parameter set in S308. However, in the determination method (3), when the range EE ′ of the exposure area in the X-axis direction determined in S309 is narrower than the exposure area EE whose accuracy is guaranteed by the exposure apparatus 100, the position coordinates that deviate from the range EE ′, FIG. Then, the position coordinates M1 and M11 are excluded from the position coordinates for controlling the exposure light amount. In the determination method (3), the relationship between the sensitivity matrix GA, the driving amount SA of each of the driving units A1 to A7, and the adjustment amount PM of the exposure light amount at each of the position coordinates M2 to M10 on the substrate is shown in FIG. ).

  The position coordinates for controlling the amount of exposure light on the substrate determined in S310 and the amount of exposure light or the amount of adjustment of the amount of exposure light at such position coordinates are used in subsequent steps (S311 and S312). In the present embodiment, the three determination methods (1) to (3) have been described as S310, but the determination method (2) and the determination method (3) are combined to control the exposure light amount on the substrate. The coordinates and the exposure light amount or the adjustment amount of the exposure light amount at the position coordinates may be determined. Further, it is assumed that the user can select an arbitrary determination method from the determination methods (1) to (3) by setting conditions and the like in advance in the exposure apparatus 100.

  In S311, a control gain matrix is calculated. The control gain matrix can be obtained from the position coordinates for controlling the amount of exposure light on the substrate set in S310 and the sensitivity matrix stored in S306, and is obtained by an inverse matrix or pseudo inverse matrix of the sensitivity matrix. Matrix.

  For example, in S310, the position coordinates for controlling the exposure light amount on the substrate set using the determination method (1) are the position coordinates M1 to M11 as described above. In this case, a pseudo inverse matrix of the sensitivity matrix (11 × 7 matrix) shown in FIG. 8A is used as a control gain matrix.

  In S310, the position coordinates for controlling the exposure light amount on the substrate set using the determination method (2) are, as described above, the position coordinates M2, M3, M4, M6, M8, M9, and M10. is there. In this case, an inverse matrix of the sensitivity matrix (7 × 7 matrix) shown in FIG. 8B is used as a control gain matrix.

  In S310, the position coordinates for controlling the exposure light amount on the substrate set using the determination method (3) are, as described above, the position coordinates M2, M3, M4, M5, M6, M7, M8, M9 and M10. In this case, a pseudo inverse matrix of the sensitivity matrix (9 × 7 matrix) shown in FIG. 8C is used as a control gain matrix.

  As described above, the control gain matrix can be obtained by using the elements of the sensitivity matrix corresponding to the position coordinates to control the exposure light amount on the substrate set in S310. The control gain matrix is calculated by the calculation unit 18a and stored in the storage unit 18b.

  In S312, a plurality of driving units A1 to A7 provided on the variable blade 201 of the slit unit 200 are driven in order to control the amount of exposure light on the substrate. Specifically, first, using the position coordinates to control the exposure light amount on the substrate determined in S310, the exposure light amount at the position coordinates or the adjustment amount of the exposure light amount, and the control gain matrix calculated in S311. , The drive amount of each of the plurality of drive units A1 to A7 is obtained. As described above, the relationship between the sensitivity matrix GA, the driving amount SA of each of the driving units A1 to A7, and the adjustment amount PM of the exposure light amount at each of the position coordinates M1 to M11 on the substrate is as shown in FIGS. This is the relationship shown in FIG. For example, when the relationship shown in FIG. 8A is modified, the driving amount SA of each of the driving units A1 to A7 can be obtained from the relationship shown in FIG. The control gain matrix GA + shown in FIG. 10 is a 7 × 11 matrix obtained from the sensitivity matrix shown in FIG. In other words, the control gain matrix GA + shown in FIG. 10 is an inverse matrix or pseudo inverse matrix of the sensitivity matrix shown in FIG. 8A, and is calculated in S311. 8B and 8C, similarly, the control gain matrix can be calculated by obtaining the inverse matrix or pseudo inverse matrix of the respective sensitivity matrices. The exposure light amount adjustment amount PM is the exposure light amount or the adjustment amount of the exposure light amount (target light amount) at the position coordinates where the light amount on the substrate is to be controlled, and is set in S310. The driving amount SA of each of the driving units A1 to A7 is calculated by the calculation unit 18a, and the driving units A1 to A7 are driven based on the driving amount SA.

  In S313, the substrate 15 is exposed (scanning exposure). In the present embodiment, the control of the slit unit 200, in particular, the driving of the driving units A1 to A7 provided on the variable blade 201 is described in detail, but actually, the substrate stage 16 is moved to the exposure start position. There is also advance preparation such as. The pattern of the mask 3 is transferred to the substrate 15 by exposing the substrate 15 at the timing when these preparations are completed. When a plurality of exposures are repeated in a substrate (for example, a plurality of shot areas are exposed) or when a plurality of substrates are exposed, the process shown in FIG. 3B may be repeated. Further, in the present embodiment, the case where the substrate 15 is exposed after driving the driving units A1 to A7 provided on the variable blade 201 has been described as an example, but the driving units A1 to A7 are driven during the exposure of the substrate 15. You may let it.

  Thus, in the exposure apparatus 100, the control gain matrix can be calculated by arbitrarily selecting elements of the sensitivity matrix acquired in advance. Further, as described above, the elements of the sensitivity matrix can be obtained for all position coordinates in the exposure area on the substrate 15. For example, the elements of the sensitivity matrix may be obtained for the position coordinates at which the exposure area on the substrate 15 is divided into 100. In other words, in the exposure apparatus 100, it is possible to arbitrarily select the position coordinates at which the amount of exposure light on the substrate is to be controlled, and this is particularly effective for exposure line width control. Quality control in device manufacturing may vary from user to user, from factory to factory, and from device to device. In such a case, even in the management of the exposure line width, the position coordinates (management position coordinates) where the exposure line width is to be measured on the substrate and the number thereof are different. In the exposure line width control, these measurement data are fed back. Being able to control the exposure light quantity with high accuracy for any position coordinates in the substrate means that the exposure light quantity can be controlled at the same position coordinates as the position coordinates of the exposure line width to be managed. Contributes to stable production.

  Further, since it is possible to arbitrarily select position coordinates for controlling the exposure light amount, it is possible to control the unevenness of the exposure light amount on the substrate with high accuracy. In the exposure apparatus 100, it is possible to control the amount of exposure light at seven or more position coordinates within the substrate for the seven driving units provided on the variable blade 201. However, as the number of position coordinates for controlling the exposure light quantity is smaller, the control accuracy of the exposure light quantity on the substrate is improved.

  11 (a) to 11 (c), the substrate position is controlled when the exposure light amount is controlled to 17 positions and when the exposure light amount is controlled to 13 positions. The effect of the exposure light amount on the control accuracy will be described. Here, as shown in FIG. 11A, it is assumed that the range EE2 in the X-axis direction of the exposure area determined in S308 is smaller than the maximum exposure area EE1. FIG. 11B shows an adjustment amount (a target light amount) of each exposure light amount of the position coordinates M1 to M17 at which the exposure light amount of the substrate 15 is to be controlled. In FIG. 11B, the position coordinates M1 to M17 are used on the horizontal axis, and the adjustment amount of the exposure light amount is used on the vertical axis. For the position coordinates M1, M2, M16, and M17 outside the range EE2 of the exposure area in the X-axis direction, it is necessary to obtain the adjustment amount of the exposure light amount by interpolation processing. In the present embodiment, the adjustment amount of the exposure light amount of the position coordinates M1 and M2 is the same as the adjustment amount of the exposure light amount of the position coordinate of the position coordinate M3, and the adjustment amount of the exposure light amount of the position coordinates M16 and M17 is the position of the position coordinate M15. It is the same as the adjustment amount of the exposure light amount of the coordinates.

  FIG. 11C shows a case where the plurality of driving units A1 to A7 provided on the variable blade 201 are driven based on the adjustment amount of the exposure light amount shown in FIG. 11B in the exposure apparatus 100 of the present embodiment. 3 shows the simulation results. In FIG. 11C, the position coordinates M1 to M17 are used on the horizontal axis, and the correction error of the exposure light amount is used on the vertical axis. Referring to FIG. 11C, by reducing the position coordinates for controlling the exposure light amount from 17 to 13 positions, the correction error of the exposure light amount on the substrate can be reduced by about 20%.

  In the present embodiment, the sensitivity matrix is described as indicating the relationship between the driving amount of each of the plurality of driving units provided on the variable blade and the amount of light incident on each position coordinate of the region on the substrate. However, the present invention is not limited to this. The sensitivity matrix indicates the relationship between the driving amount of each of the plurality of driving units provided on the variable blade and the dimension (line width) of a pattern formed by light incident on each position coordinate of the region on the substrate. It may be. In this case, the sensitivity matrix includes a coefficient indicating a sensitivity of a change in a dimension of a pattern formed by light incident on each position coordinate with respect to driving of one of the plurality of driving units provided on the variable blade. Included as In this case, the slit unit 200 is controlled by the control unit 18 so that the dimension of the pattern formed by the light incident on each position coordinate of the region on the substrate corresponding to the opening OP becomes the target dimension (target line width). Is done.

  Thus, the exposure apparatus 100 of the present embodiment is advantageous for adjusting the amount of light on the substrate. Therefore, the exposure apparatus 100 can accurately transfer the pattern of the mask 3 onto the substrate 15, that is, can expose the substrate 15 with high accuracy.

  The method for manufacturing an article according to the embodiment of the present invention is suitable for manufacturing an article such as a device (semiconductor element, magnetic storage medium, liquid crystal display element, and the like). Such a manufacturing method includes a step of exposing the substrate coated with the photosensitive agent using the exposure apparatus 100 and a step of developing the exposed substrate. Further, such a manufacturing method may include other well-known steps (oxidation, film formation, vapor deposition, doping, flattening, etching, resist peeling, dicing, bonding, packaging, and the like). The method for manufacturing an article according to the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article as compared with the related art.

  The preferred embodiments of the present invention have been described above. However, it is needless to say that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

100: exposure apparatus 200: slit section 201: variable blade 203 to 209: drive section 3: mask 15: substrate 18: control section

Claims (13)

An exposure apparatus for exposing a substrate, comprising:
A blade for shaping light from a light source to form an opening that defines the shape of an exposure area on the substrate,
Including a plurality of drive units provided at a plurality of locations of the blade, an adjustment unit that adjusts the shape of the opening by driving the plurality of drive units,
A control unit that controls the adjustment unit,
Wherein the control unit includes a respective drive amounts of the plurality of drive portions, the sensitivity matrix showing the relationship between the exposure amount of light incident on each position coordinates of the exposure area on the front Stories substrate through said opening and on the basis of the target dew amount on the substrate to determine the respective driving amounts of said plurality of drive portions, based on the determined driving amount by driving the plurality of driving portions,
The sensitivity matrix is an exposure apparatus which comprises a coefficient indicating the exposure light amount sensitivity of the change in the light incident on the respective position coordinates relative to the drive of one drive unit as an element.   The control unit obtains a control gain matrix that is an inverse matrix or a pseudo inverse matrix of the sensitivity matrix, and determines a drive amount of each of the plurality of drive units using the control gain matrix. 2. The exposure apparatus according to 1. Further comprising a setting unit for setting a pre-Symbol first position coordinates to be controlled dew light amount of the exposure area on a substrate,
The exposure apparatus according to claim 2, wherein the control unit obtains the control gain matrix using an element of the sensitivity matrix corresponding to the first position coordinate. Wherein, prior SL obtains the target exposure amount at the first position coordinates to be controlled dew light amount of the exposure area on the substrate, based on a target exposure amount in the sensitivity matrix and the first position coordinates The exposure apparatus according to claim 1, wherein a driving amount of each of the plurality of driving units is determined. Wherein the control unit, according to claim 4, characterized in that acquires a target exposure amount in the second position coordinates said set exposure amount from the setting exposure light amount set by the user for the first position coordinates are not set Exposure apparatus according to 1. Wherein, said the second position coordinate, the exposure apparatus according to claim 5, characterized in that to obtain the target exposure amount through interpolation processing using the setting exposure light quantity. Before Symbol further comprising a measuring unit for measuring dew quantity of light incident to each position coordinates of the exposure area on the substrate,
Wherein, for each of the plurality of drive unit drives the drive unit to at least two drive positions, the respective position coordinates of the exposure region before SL on the substrate in each of the two driving positions The exposure apparatus according to claim 1, wherein the sensitivity matrix is obtained by performing measurement by a measurement unit. Wherein the control unit as a reference position a position of the plurality of drive unit when a dew light amount unevenness in the region before SL on the substrate is equal to or less than the threshold, the two driving positions in a predetermined range from the reference position The exposure apparatus according to claim 7, wherein the setting is performed. Wherein the control unit, the result of the measurement portion of the measurement of only the position coordinates of the previous SL range that has a valid the sensitivity to driving of said one driving unit of the respective position coordinates of the exposure area on the substrate 9. The exposure apparatus according to claim 7 , wherein the sensitivity matrix is obtained based on the following .   The exposure apparatus according to claim 1, further comprising a storage unit that stores the sensitivity matrix. Further comprising an illumination optical system for illuminating a mask having a pattern to be transferred to the substrate,
The illumination optical system includes a changing unit that changes an illumination condition for illuminating the mask,
The exposure apparatus according to claim 10, wherein the storage unit stores the sensitivity matrix for each of the illumination conditions. An exposure apparatus for exposing a substrate, comprising:
A blade for shaping light from a light source to form an opening that defines the shape of an exposure area on the substrate,
Including a plurality of drive units provided at a plurality of locations of the blade, an adjustment unit that adjusts the shape of the opening by driving the plurality of drive units,
A control unit that controls the adjustment unit,
Wherein, the respective driving amounts of said plurality of drive portions, the relationship between the dimensions of the pattern formed by the light entering through said opening in each of the position coordinates of the exposure region before SL on the substrate Based on the sensitivity matrix shown and the target dimensions of the pattern, determine the drive amount of each of the plurality of drive units, drive the plurality of drive units based on the determined drive amount,
The exposure apparatus according to claim 1, wherein the sensitivity matrix includes, as an element, a coefficient indicating a sensitivity of a change in a dimension of a pattern formed by light incident on each of the position coordinates with respect to driving of one driving unit. A step of exposing a substrate using the exposure apparatus according to any one of claims 1 to 12,
Developing the exposed substrate;
A method for producing an article, comprising:

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