TWI889111B - Projection aligner - Google Patents

Abstract

This is a projection exposure apparatus that measures changes in the performance of a projection lens with high precision without affecting takt time. The transport control unit controls transport of the substrate stage and the aberration/misalignment measurement stage so that the aberration/misalignment measurement stage is located at the projection exposure position while the substrate stage is located at the substrate exchange position. The imaging control section is configured such that while the aberration/positional deviation measurement stage is positioned at the projection exposure position by the transport control section, the alignment mark imaging section images the positional deviation detection mark, and the aberration detection mark imaging section The imaging of the alignment mark imaging section and the aberration detection mark imaging section is controlled so that the mask side aberration detection mark and the reference mask side aberration detection mark are imaged.

Description

Projection exposure device

The present invention relates to a projection exposure device.

Patent document 1 (Japanese Patent Publication No. 9-50959) describes a projection exposure device including a substrate symbol detection optical system, a mask symbol detection optical system, and a correction mechanism, wherein the substrate symbol detection optical system does not illuminate the substrate symbol with a first detection light of a broadband wavelength through a projection optical system, and does not receive the first detection light from the substrate symbol through a projection optical system, thereby detecting the substrate symbol; the mask symbol detection optical system illuminates the mask symbol with a second detection light through the projection optical system, and receives light from the mask symbol, thereby detecting the mask symbol; the correction mechanism is arranged between the mask and the substrate in order to correct the chromatic aberration (axial chromatic aberration, lateral chromatic aberration (distortion) etc.) of the projection optical system relative to the reflected second detection light on the substrate. In other words, Patent Document 1 describes a method of detecting and correcting the aberration of the projection optical system by comparing the symbols set on the mask and the symbols set on the projection exposure position side.

Patent document 2 (Japanese Patent Publication No. 10-172907) describes a projection exposure apparatus including a first positioning system and a second positioning system, wherein the first positioning system irradiates a first positioning light having a different wavelength from the exposure irradiation light to a first reference symbol arranged on the image plane side of a projection optical system, and detects light information generated from the first reference symbol by the projection optical system; the second positioning system irradiates a second positioning light having a wavelength approximately the same as the exposure irradiation light to a symbol on a mask and a second reference symbol arranged on the image plane side of the projection optical system, and then detects the two symbols by the projection optical system, and detects the offset amount generated by chromatic aberration. In other words, Patent Document 2 describes a method of detecting and correcting the aberration of the projection optical system by comparing the symbols set on the mask and the symbols set on the projection exposure position side.

Patent document 3 (US Patent US7403264B2) describes a lithography projection device including a projection system for projecting patterned light onto an object portion of a substrate to form an image, predicting the aberration change of the projection system due to the passage of time relative to the measured aberration value, and determining the application-specific effect of the predicted aberration change of the projection system on the parameters of at least one image for the selected pattern, and then generating a control signal specific to the selected pattern based on the predicted aberration change of the projection system and the application-specific effect of the parameters of at least one image, and responding to the control signal to compensate for the application-specific effect of the predicted aberration change of the projection system on the image.

Patent document 4 (Japanese Patent Publication No. 11-168062) describes a projection exposure device including a substrate stage, a projection optical system, a first symbol detection mechanism, and a second symbol detection mechanism, wherein the first symbol detection mechanism is located outside the projection field of view of the projection optical system, has a detection center at a first position at a fixed interval from the optical axis of the projection optical system, and can optically detect symbols on the photosensitive substrate; the second symbol detection mechanism optically detects a specific symbol among multiple symbols of the mask, which exists at a second position approximately fixed within the field of view of the projection optical system. The invention also describes a reference symbol plate provided on a part of a substrate stage in the projection exposure apparatus, wherein a first reference symbol detectable by a first symbol detection mechanism and a second reference symbol detectable by a second symbol detection mechanism via a projection optical system are arranged side by side at a fixed positional relationship corresponding to the interval between the first position and the second position; a first positioning mechanism for positioning the substrate stage in such a manner that the second reference symbol is detected by the second symbol detection mechanism; a second positioning mechanism for positioning the mask stage in such a manner that the two symbols are in a preset positional relationship by detecting both a specific symbol of the mask and the second reference symbol by the second symbol detection mechanism; and a state in which a positional deviation between a detection center and the first reference symbol is detected by the first symbol detection mechanism and the positional deviation is memorized as a baseline error. In other words, the patent document 4 describes the state of detecting the positional offset between the first reference symbol on the photosensitive substrate and the detection center of the first symbol detection mechanism.

Patent document 5 (Japanese Patent Publication No. 10-12520) describes the method of detecting light emitted from a first symbol on a photomask and light emitted from a second symbol in an irradiation area on a substrate on which a pattern of a photomask is transferred and passing through the photomask at a position with a fixed interval from the first symbol in a first direction, measuring the positional offset of the first symbol and the second symbol in a second direction perpendicular to the first direction, detecting the rotation angle of the irradiation area and the photomask, and partially correcting the measured positional offset with a compensation amount corresponding to the measured rotation angle, and performing alignment of the photomask and the irradiation area in the second direction according to the corrected positional offset of the first symbol and the second symbol.

Patent document 6 (US Patent Publication US20110027542A1) describes the method of detecting the positioning symbol of the workpiece and the positioning symbol of the mask by a positioning camera, calculating the position offset of the mask and the workpiece and the deformation of the workpiece according to the offset of the two positioning symbols detected by the positioning camera, and adjusting the positioning of the workpiece and the mask based on the calculated position offset.

Patent document 7 (Japanese Patent Publication No. 9-260273) describes an exposure device comprising a first measuring mechanism, a stage, a second measuring mechanism, a third measuring mechanism, a fourth measuring mechanism, and a mask driving mechanism, wherein the first measuring mechanism observes the alignment mark on the photosensitive substrate through the projection optical system and measures the deviation from the reference mark it has; the stage carries the photosensitive substrate and is driven in a parallel direction and a perpendicular direction relative to the projection optical system; the second measuring mechanism The first measuring mechanism measures the driving position of the stage in the parallel and vertical directions; the third measuring mechanism measures the pattern on the mask and the pattern on the photosensitive substrate through the projection lens, and the pattern on the mask and the calibration pattern set on the first stage for calibration of the first measuring mechanism, and measures at the same time; the fourth measuring mechanism includes a mask reference symbol, and measures at the same time by superimposing the symbol on the mask and the illumination reference symbol; the mask driving mechanism drives the mask in the X, Y and θ directions. In other words, the patent document 7 describes the state of obtaining and correcting the coordinates of the mask and the magnification error of the projection lens by positioning the reference pattern and calibration symbol on the mask side using an on-axis alignment system.

[Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 9-50959

[Patent Document 2] Japanese Patent Publication No. 10-172907

[Patent Document 3] US Patent US7403264B2

[Patent Document 4] Japanese Patent Publication No. 11-168062

[Patent Document 5] Japanese Patent Publication No. 10-12520

[Patent Document 6] US Patent Publication US20110027542A1

[Patent Document 7] Japanese Patent Publication No. 9-260273

In a projection exposure device (stepper), the resolution and overlap (positioning) accuracy of the formed pattern are the most important performances. In addition, since it is a manufacturing device, high productivity (short takt time) is also expected.

On the other hand, the lens (projection lens) of the projection mask pattern is relatively weak to changes in air pressure or temperature. Due to changes in air pressure or temperature during production, or even light energy during exposure, the performance of the lens will gradually change. Since this change will have a greater impact on exposure performance, it is necessary to measure or predict this change during production, make various corrections, and frequently maintain fixed performance.

In correction control, it is necessary to have a technique to measure the performance (aberration) changes of the projection lens. There are various methods to measure individual aberrations. However, the known technique of measuring these aberrations with high precision requires stopping the production operation for measurement, which is the cause of a significant deterioration in production capacity.

The present invention is to measure the performance changes of the projection lens with high precision without affecting the cycle time.

The first aspect is a projection exposure device, which projects a mask pattern onto a substrate transported to a projection exposure position via a projection optical system, and forms a mask-side aberration detection symbol on the mask for detecting aberration or aberration change of the projection optical system. The projection exposure device includes: a positioning symbol photographing unit, which photographs a positioning symbol arranged on the substrate; a substrate stage, which carries the substrate; an aberration/position offset measuring stage, which carries a reference mask and an aberration detection symbol photographing unit, wherein the reference mask forms a reference mask-side aberration detection symbol for detecting aberration or aberration change of the projection optical system, and forms a position offset detection symbol for measuring a position offset relative to a reference position of the positioning symbol photographing unit, and the aberration detection symbol photographing unit clamps The reference mask is held and images are taken of the aberration detection symbol on the mask side and the aberration detection symbol on the reference mask side from the opposite side of the projection optical system; a transport control unit controls the transport of the substrate stage and the aberration/position offset measurement stage in such a manner that the aberration/position offset measurement stage is located at the projection exposure position when the substrate stage is located at the substrate exchange position; and a photography control unit controls the transport of the substrate stage and the aberration/position offset measurement stage after the substrate stage is located at the substrate exchange position. When the transport control unit places the aberration/position offset measuring stage at the projection exposure position, the positioning symbol photographing unit photographs the position offset detection symbol, and the aberration detection symbol photographing unit photographs the mask side aberration detection symbol and the reference mask side aberration detection symbol, thereby controlling the photography of the positioning symbol photographing unit and the aberration detection symbol photographing unit.

The second aspect is a projection exposure device that performs photography controlled by the photography control unit each time the substrate mounted on the substrate stage is exchanged at the substrate exchange position in the first aspect.

The third aspect is a projection exposure device in which, in the second aspect, at the substrate exchange position, each time the substrate mounted on the substrate stage is exchanged, the positional offset of the positioning symbol photography section is corrected according to the result of the photography through the photography control section, and the aberration or aberration change of the projection optical system is corrected.

Through the first, second and third aspects, the performance changes of the projection lens can be measured with high precision without affecting the cycle time.

10: Photomask

20: Projection optical system

30:Substrate

40: Alignment mask photography unit

50:Substrate table

60: Reference mask

70: Symbol photography unit for aberration detection

80: Aberration/position deviation measurement platform

85: Connecting parts

86: One-piece pedestal

90: Transportation Control Department

100: Photography control unit

110: Aberration/position shift measurement unit

120: Aberration/position shift correction unit

170:Erection

200: Projection exposure device

210: Light box

211: Light source

220: Mask projection optical system

221: Shield

230: Mask stage

250:Substrate transport department

260:Substrate exchange department

261: Suction pad

270: Mask library

280: Multi-joint robot for mask transportation

281:Hands

290:Shock absorber

M61, M62: Symbols for detecting the side aberration of the reference mask

M63: Symbol for position deviation detection

M11, M12, M13, M14: Symbols for detecting mask side aberrations

M31: Positioning symbol

AR1: Irradiation area

AR2: Projection exposure area

P1: Projection exposure position

P2: Substrate exchange position

P3: Retreat position

IL: Irradiation light

Figure 1 is a three-dimensional diagram showing the overall structure of the projection exposure device in an implementation state.

FIG2A is a schematic diagram showing a portion of the projection exposure device of the embodiment.

FIG2B is a schematic diagram showing a portion of the projection exposure device of the embodiment.

FIG3A is a diagram showing an example of the structure of a photomask.

Figure 3B is a schematic diagram of the symbols on the enlarged mask.

Figure 3C is a schematic diagram of the symbols on the enlarged mask.

Figure 3D is a schematic diagram of the symbols on the enlarged mask.

Figure 4 is a diagram showing an example of the configuration of a projection optical system.

Figure 5 is a schematic diagram showing the positional relationship between the positioning symbol photography unit and the substrate when viewed from the top surface.

FIG6A is a diagram showing an example of the construction of a reference mask.

Figure 6B is a schematic diagram of the symbols on the enlarged reference mask.

Figure 6C is a schematic diagram of the symbols on the enlarged reference mask.

Figure 6D is a schematic diagram of the symbols on the enlarged reference mask.

FIG6E is a diagram showing the relationship between the symbols on the mask in the photographic image and the symbols on the reference mask.

Figure 6F is a diagram showing the relationship between the symbols on the mask in the photographic image and the symbols on the reference mask.

FIG7 is a flow chart showing the processing sequence of the control of the projection exposure device in the implementation mode.

FIG8A is a schematic diagram corresponding to FIG2A, showing a portion of the projection exposure device of the embodiment.

FIG8B is a schematic diagram corresponding to FIG2B, showing a portion of the projection exposure device of the embodiment.

The following is an explanation of the implementation of the projection exposure device of the present invention with reference to the drawings.

FIG1 is a three-dimensional diagram showing the overall structure of the projection exposure device 200 of the embodiment.

Figures 2A and 2B are schematic diagrams showing a portion of the projection exposure device 200 in an implementation example.

Figure 2A and Figure 2B are views of Figure 1 from the side indicated by arrow A.

The projection exposure device 200 shown in FIG1 includes a lamp house 210, a mask blind projection optical system 220, a mask stage 230, a projection optical system 20, a substrate stage 50, an aberration/position shift measuring stage 80, a substrate transport unit 250, a substrate exchange unit 260, a mask library 270, a multi-joint robot 280 for mask transport, and a vibration reduction device 290.

The light box 210 is a shell having a mercury lamp as an exposure light source 211 for emitting exposure light IL. The mercury lamp uses, for example, a spectrum of mercury emitting a wavelength of 365nm.

The mask shield projection optical system 220 projects the shield 221 that limits the exposure area onto the mask 10 via a dedicated optical system 220.

The mask 10 is loaded/held on the mask stage 230.

The projection optical system 20 allows the pattern image depicted on the irradiation area AR1 of the mask 10 to be imaged on the projection exposure area AR2 of the substrate 30 transported to the projection exposure position P1.

The substrate 30 is placed/held on the substrate stage 50.

The aberration/position shift measuring platform 80 is a platform for measuring the aberration or aberration change of the projection optical system 20 and the position shift of the positioning symbol photography unit 40, and it carries and holds the reference symbol 60.

The substrate transport unit 250 transports the substrate stage 50 to the substrate exchange position P2 and the projection exposure position P1 in the X direction, and transports the aberration/position shift measuring stage 80 to the projection exposure position P1 and the retreat position P3 in the X direction.

The substrate exchange unit 260 exchanges the substrate 30 on the substrate stage 50 at the substrate exchange position P2.

The mask library 270 is a storage rack that prevents foreign matter from adhering to the surface of the mask 10 and stores multiple masks 10 for exchange. It stores multiple masks 10 in an intermittent arrangement.

The multi-joint robot 280 for transporting masks is a robot that responds to a request to change the projection exposure pattern image formed on the substrate 30 and performs processing for exchanging the mask 10 on the mask stage 230. The multi-joint robot 280 for transporting masks transports the mask 10 from the mask stage 230 by driving and controlling the robot axes and controlling the gripping and opening of the hand 281 at the front end of the arm, and takes out a new mask 10 from the mask library 270 and transports it to the mask stage 230.

The shock absorbing device 290 is installed between the stand 170 on which the projection optical system 20, substrate stage 50, and mask stage 230 are mounted and the floor of the clean room. The shock absorbing device 290 maintains the positional relationship between the projection optical system 20, substrate 30, and mask 10 with high precision, and prevents or suppresses vibration from being transmitted to the projection optical system 20, substrate stage 50, and mask stage 230.

As shown in FIG. 2B , the projection exposure device 200 projects the pattern of the mask 10 onto the substrate 30 transported to the projection exposure position P1 via the projection optical system 20 .

As shown in FIG. 2A and FIG. 2B, the projection exposure device 200 includes a mask 10, a projection optical system 20, a substrate 30, a positioning symbol photography unit 40, a substrate stage 50, a reference mask 60, an aberration detection symbol photography unit 70, an aberration/position shift measurement stage 80, a transport control unit 90, a photography control unit 100, an aberration/position shift measurement unit 110, and an aberration/position shift correction unit 120. The transport control unit 90, the photography control unit 100, the aberration/position shift measurement unit 110, and the aberration/position shift correction unit 120 constitute a controller 190 of the projection exposure device 200.

(Photomask)

FIG3A is a diagram showing an example of the structure of the photomask 10. FIG3A is a diagram observed from the upper surface of the photomask 10.

The mask 10 is a plate on which an exposure image of a projection pattern PT1 as a circuit pattern is drawn in an irradiation area AR1 on a glass substrate, for example. In addition to the projection pattern PT1, mask side aberration detection symbols M11, M12, M13, and M14 are formed on the mask 10. The mask side aberration detection symbols M11, M12, M13, and M14 are used to detect the aberration R or aberration change △R of the projection optical system 20. The mask side aberration detection symbols M11, M12, M13, and M14 are formed at a position far from the irradiation area AR1.

As shown in the enlarged view of FIG. 3B , the symbols M11 and M12 for detecting the side aberration of the mask are symbols for detecting the positional deviation of the mask 10, and the portion through which the irradiation light IL does not pass is drawn as a circle or an ellipse filled with black, for example.

As shown in the enlarged view of FIG3C , the symbols M13 and M14 for detecting the side aberration of the mask are symbols for detecting the focal length, and are drawn as a plurality of lines with a width of black lines (the part through which the irradiation light IL does not pass) and a spacing between each line (the part through which the irradiation light IL passes) of 5μm.

The mask side aberration detection symbols M11 and M12 can be in any shape or pattern as long as they can detect the positional deviation of the mask 10. For example, as shown in FIG. 3D , the mask side aberration detection symbols M11 and M12 can also be in the shape of a cross.

(Projection optical system)

FIG. 4 is a diagram showing an example of the configuration of the projection optical system 20. FIG. 5 is a diagram showing each projection area in a view of the substrate 30 viewed from the top surface. The following description will be made with reference to FIG. 3A, FIG. 4, and FIG. 5.

As shown in FIG. 4 , the projection optical system 20 is a reduction or magnification lens optical system composed of a plurality of projection lens groups such as plano-convex, biconvex, plano-concave, and biconcave lenses. The projection optical system 20 optically reduces or maintains the original size of the image of the projection pattern PT1 of the irradiation area AR1 of the mask 10, and projects and exposes the fixed projection area AR2 on the substrate 30 as the projection exposure pattern PT2.

The image of the irradiation area AR1 of the mask 10 shown in FIG3A is projected onto the projection area AR2 on the substrate 30 shown in FIG5. Here, as shown by the arrows in FIG5, the exposure position is controlled by sequentially exposing the projection exposure pattern PT2 in each projection area AR2 on the substrate 30. For example, the exposure position is controlled by driving the substrate stage 50 in the X and Y directions.

(Substrate)

The substrate 30 can be any object as long as the projection exposure pattern can be projected onto it. In the embodiment, for example, a flip chip-ball grid array (FC-BGA) substrate is envisioned. In the projection exposure of the FC-BGA substrate, the process takes time because the number of build-ups is repeated, and the wiring patterns of each layer are fine and dense. Therefore, in the projection exposure device 200, although the production cycle is shortened, the positioning accuracy is high, and the aberration is suppressed to the extreme. High resolution, the projection exposure device 200 of this embodiment is still suitable.

As shown in FIG. 5 , a positioning symbol M31 is formed on the substrate 30 . FIG. 5 shows the positional relationship between the positioning symbol photographing unit 40 and the positioning symbol M31 described below. Five positioning symbols M31 are arranged along the arrangement direction of the positioning symbol photographing unit 40 , i.e., the Y-axis direction, and four are arranged along the X-axis direction. The positioning symbols M31 are arranged, for example, at the four corners of the projection area AR2 of the eight rectangles.

(Location symbol photography department)

The positioning symbol photographing unit 40 photographs the positioning symbol M31 disposed on the substrate 30.

The positioning symbol photographing unit 40 is constituted, for example, by a microscope camera in which a digital camera is mounted on a microscope. As shown in FIG5 , the positioning symbol photographing unit 40 is configured along the Y-axis direction in such a way that five positioning symbols M31 arranged along the Y-axis direction on the substrate 30 can be photographed from above.

As shown in FIG2B , the photographic image signal S1 representing the image photographed by the positioning symbol photographing unit 40 is sent to the photographing control unit 100 wirelessly or wiredly.

(Substrate table)

As shown in FIG. 2A , the substrate stage 50 carries and holds the substrate 30 and is driven in the three-dimensional directions of X, Y, and Z via the substrate transport unit 250 , and is driven in the tilting direction around the X-axis and the Y-axis and the rotation direction around the Z-axis.

The substrate 30 on the substrate stage 50 is exchanged at the substrate exchange position P2 via the substrate exchange unit 260. For example, the substrate exchange unit 260 is composed of a substrate transport arm 262 having a suction pad 261. The substrate 30 is held by the suction pad 261 and the substrate transport arm 262 is driven and controlled to carry in and out the substrate 30.

In the projection exposure device 200 of the embodiment, as shown by the arrow in FIG. 5 , by driving the substrate stage 50 in the X and Y directions in a step-and-repeat manner, the projection exposure pattern PT2 is sequentially exposed in each projection area AR2 of the substrate 30 .

(Benchmark mask)

As shown in FIG. 2A , the reference mask 60 is mounted on the aberration/position deviation measuring table 80 .

FIG. 6A is a diagram showing an example of the structure of the reference mask 60. FIG. 6A is a diagram showing the reference mask 60 as viewed from the top surface.

The reference mask 60 is formed of, for example, a glass substrate, on which reference mask side aberration detection symbols M61 and M62 and position shift detection symbol M63 are formed.

The reference mask side aberration detection symbols M61 and M62 correspond to the mask side aberration detection symbols M11 and M12 respectively, and are used to detect the aberration R or the aberration change △R of the projection optical system 20.

The position deviation detection symbol M63 is a symbol used to measure the position deviation △Q relative to the reference position Q0 of the positioning symbol imaging unit 40.

As shown in the enlarged form of FIG. 6B , the reference mask side aberration detection symbols M61 and M62 are used to detect the relative positions of the mask side aberration detection symbols M11 and M12 as symbols for the positional offset of the mask 10, for example, the portion through which the irradiation light IL does not pass is depicted as an elliptical frame or a circular frame. The reference mask side aberration detection symbols M61 and M62 can be in any shape or pattern as long as they can detect the positional offset of the mask 10. For example, the reference mask side aberration detection symbols M61 and M62 are shown in FIG. 6C , and the portion through which the irradiation light IL does not pass can also be formed as a square frame.

As shown in FIG6A, the position offset detection symbol M63 is, for example, depicted as a grid pattern along the arrangement direction (Y-axis direction) of the positioning symbol photography unit 40. The position offset detection symbol M63 can be in any shape or pattern as long as it can measure the position offset △Q of the positioning symbol photography unit 40. For example, the position offset detection symbol M63 can also be depicted as a ruler along the arrangement direction (Y-axis direction) of the positioning symbol photography unit 40 as shown in FIG6D.

(Symbol photography unit for aberration detection)

As shown in FIG. 2A , the aberration detection symbol imaging unit 70 is mounted on the aberration/position shift measuring platform 80.

In FIG. 2A , the aberration detection symbol photographing unit 70 is disposed below the reference mask 60. The aberration detection symbol photographing unit 70 photographs the mask-side aberration detection symbols M11, M12, M13, and M14 and the reference mask-side aberration detection symbols M61 and M62 from the opposite side of the projection optical system 20, sandwiching the reference mask 60. The aberration detection symbol photographing unit 70 is constituted by, for example, a digital camera. The aberration detection symbol imaging section 70 includes an aberration detection symbol imaging section 70A located on the substrate exchange position P2 side, an aberration detection symbol imaging section 70B located on the retreat position P3 side, and an aberration detection symbol imaging section 70C located between the two and on the optical axis 20C.

The photographic image signal S2 representing the image photographed by the aberration detection symbol photographing unit 70 is sent to the photographing control unit 100 wirelessly or wiredly.

(Aberration/position offset measurement platform)

As shown in FIG. 2A , the aberration/position shift measuring stage 80 places and holds the reference mask 60 on its upper surface, and the aberration detection symbol imaging unit 70 is mounted below the reference mask 60 and driven in the three-dimensional directions of X, Y, and Z via the substrate transport unit 250 .

The substrate transport unit 250, substrate stage 50, aberration/position shift measuring stage 80, projection optical system 20, and mask 10 are supported by the vibration absorbing device 290 via the stand 170.

(Transportation Control Department)

As shown in FIG. 2A and FIG. 2B, the transport control unit 90 drives the substrate transport unit 250 and controls the positions of the substrate stage 50 and the aberration/position offset measuring stage 80 in the three-dimensional directions of X, Y, and Z. In addition, the transport control unit 90 controls the posture of the substrate stage 50 in the tilt direction around the X-axis and Y-axis and the rotation direction around the Z-axis (hereinafter referred to as position and posture control).

As shown in FIG. 2A , the transport control unit 90 controls the transport of the substrate stage 50 and the aberration/position shift measuring stage 80 via the substrate transport unit 250 in such a manner that when the substrate stage 50 is at the substrate exchange position P2, the aberration/position shift measuring stage 80 is at the projection exposure position P1.

Furthermore, as shown in FIG. 2B , the transport control unit 90 controls the transport of the substrate stage 50 and the aberration/position shift measuring stage 80 via the substrate transport unit 250 in such a manner that when the substrate stage 50 is at the projection exposure position P1, the aberration/position shift measuring stage 80 is at the retreat position P3.

In the embodiment, the substrate stage 50 and the aberration/position offset measuring stage 80 are controlled and transported in a manner such that they are synchronously positioned at adjacent positions (P2, P1) or (P1, P3).

(Photography Control Department)

When the aberration/position shift measuring stage 80 is located at the projection exposure position P1 via the transport control unit 90, the imaging control unit 100 controls the imaging of the positioning symbol imaging unit 40 and the aberration detection symbol imaging unit 70 by using the positioning symbol imaging unit 40 to photograph the position shift detection symbol M63, and the aberration detection symbol imaging unit 70 to photograph the mask side aberration detection symbols M11, M12, M13, M14 and the reference mask side aberration detection symbols M61, M62.

(Aberration/position shift measurement unit)

The aberration/position shift measuring unit 110 measures the position shift △Q of the positioning symbol photography unit 40 and measures the aberration R or aberration change △R of the projection optical system 20 based on the photography result obtained by the photography control unit 100 each time the substrate 30 mounted on the substrate stage 50 is exchanged at the substrate exchange position P2.

(Aberration/position shift correction unit)

The aberration/position shift correction unit 120 corrects the position shift △Q of the positioning symbol photography unit 40 according to the measured value of the position shift △Q of the positioning symbol photography unit 40 each time the substrate 30 mounted on the substrate stage 50 is exchanged at the substrate exchange position P2, and corrects the aberration R or aberration change △R of the projection optical system 20 according to the measured value of the aberration R or aberration change △R of the projection optical system 20.

(Control processing order)

FIG7 is a flow chart showing the processing sequence of the control of the projection exposure device 200 in the implementation mode.

(Mask exchange and setup processing S11)

As shown in FIG1 , the mask 10 is transported from the mask stage 230 by the multi-joint robot 280 for mask transport, and a new mask 10 is taken out from the mask library 270 and placed on the mask stage 230 .

(Substrate exchange process and aberration/position shift correction process S12)

As shown in FIG. 2A , the substrate stage 50 is positioned at the substrate exchange position P2, and the aberration/position shift measurement stage 80 is positioned at the projection exposure position P1.

The substrate 30 on the substrate stage 50 is exchanged at the substrate exchange position P2 via the substrate exchange unit 260. In addition, the substrate 30 is carried in and out, for example, via a roller conveyor (not shown).

The photography control unit 100 controls photography by the positioning symbol photography unit 40 by sending a photography command signal to the positioning symbol photography unit 40. A photography image signal S1 representing an image photographed by the positioning symbol photography unit 40 is input to the photography control unit 100.

The aberration/position shift measuring unit 110 measures the position shift ΔQ of the positioning symbol photographing unit 40 based on the photographic image signal S1. In other words, the aberration/position shift measuring unit 110 measures the change in the relative position of the positioning symbol photographing unit 40 relative to the projected image.

When the positioning symbol photographing unit 40 is located at the reference position Q0, the position shift detection symbol M63 is photographed at the preset reference position in the photographic image. However, when the positioning symbol photographing unit 40 is located at a position shifted from the preset reference position in the photographic image, the position shift detection symbol M63 is photographed at a position shifted from the preset reference position in the photographic image. The aberration/position shift measuring unit 110 measures the position shift △Q of the positioning symbol photographing unit 40 by measuring the amount of the position shift detection symbol M63 shifted from the reference position in the photographic image through image processing, for example.

The aberration/position offset correction unit 120 corrects the position offset △Q of the positioning symbol photography unit 40 according to the measured value of the position offset △Q of the positioning symbol photography unit 40. If there is a mechanism that can adjust the position and posture of the positioning symbol photography unit 40, the position offset △Q of the positioning symbol photography unit 40 can be corrected by adjusting the position and posture of the positioning symbol photography unit 40. If there is no mechanism that can adjust the position and posture of the positioning symbol photography unit 40, in the alignment process S13 described later, the position offset △Q of the positioning symbol photography unit 40 can be corrected by moving the substrate stage 50 by adding the measured value of the position offset △Q of the positioning symbol photography unit 40.

The photography control unit 100 controls photography by the aberration detection symbol photography unit 70 by sending a photography command signal to the aberration detection symbol photography unit 70. A photography image signal S2 representing an image photographed by the aberration detection symbol photography unit 70 is input to the photography control unit 100.

The aberration/position shift measuring unit 110 measures the aberration R or aberration change △R of the projection optical system 20 based on the photographic image signal S2. In other words, the aberration/position shift measuring unit 110 measures the focal length change in the optical axis 20C direction of the projection optical system 20, the change of the image plane, the magnification change accompanying the thermal expansion change of the mask 10, and the distortion change. As described below, various aberrations R can be measured.

(Position offset of mask 10)

When the aberration R of the projection optical system 20 is below the reference level, the relative positional offset between the mask side aberration detection symbols M11, M12 and the reference mask side aberration detection symbols M61, M62 in the photographic image falls below the preset threshold. However, as shown in FIG. 6E , when the aberration R of the projection optical system 20 exceeds the reference level, the relative positional offset between the mask side aberration detection symbols M11, M12 and the reference mask side aberration detection symbols M61, M62 in the photographic image exceeds the preset threshold. The aberration/position shift measuring unit 110 moves the position of the mask 10 and measures the relative position shift from the center position of the mask side aberration detection symbols M11 and M12 in the photographed image of the aberration detection symbol photographing units 70A and 70B to the center position of the reference mask side aberration detection symbols M61 and M62 from the shifted position to the consistent position. The measured relative position shift is taken as the aberration R (position shift of the mask 10) of the projection optical system 20.

(Focal length change of projection lens and image distortion)

Furthermore, when the aberration R of the projection optical system 20 is below the reference level, the offset of the best focal position relative to the image plane of the mask side aberration detection symbols M13 and M14 falls below the preset threshold. However, when the aberration R of the projection optical system 20 exceeds the reference level, the offset of the best focal position relative to the image plane of the mask side aberration detection symbols M13 and M14 exceeds the preset threshold. The aberration/position offset measuring unit 110 moves the aberration detection symbol photographing unit 70C in the up-down direction and measures the up-down movement amount at which the contrast of the stripe pattern of the mask side aberration detection symbols M13 and M14 in the photographed image reaches the best height position (best focal position). The measured change in the vertical direction of the aberration detection symbol imaging unit 70C is taken as the aberration R of the projection optical system 20 (the change in the focal length of the projection lens and the distortion of the image surface).

(Changes in magnification of projection lens)

Furthermore, when the aberration R of the projection optical system 20 is below the reference level, the size difference between the mask side aberration detection symbols M11, M12 and the reference mask side aberration detection symbols M61, M62 in the photographic image falls below the preset threshold. However, as shown in FIG. 6F , when the aberration R of the projection optical system 20 exceeds the reference level, the size difference between the mask side aberration detection symbols M11, M12 and the reference mask side aberration detection symbols M61, M62 in the photographic image exceeds the preset threshold. The aberration/position shift measuring unit 110 measures the shift of the size difference between the mask side aberration detection symbols M11, M12 and the reference mask side aberration detection symbols M61, M62 in the photographic image through image processing. The measured size difference is taken as the aberration R of the projection optical system 20 (the magnification change of the projection lens).

The aberration/position shift correction unit 120 corrects the aberration R of the projection optical system 20 according to the measured value of the aberration R of the projection optical system 20. For example, by driving a portion of the projection lenses 21 and 22 in the projection optical system 20 in the direction of the optical axis 20C, i.e., the Z-axis direction, the focal position or projection magnification through the projection optical system 20 can be adjusted and the aberration R can be corrected. In addition, by driving the mask stage 230 in the X and Y directions, the X and Y positions of the mask 10 can be adjusted and the aberration R can be corrected.

In addition to correcting the aberration R, the aberration change △R of the current aberration relative to the previous aberration can also be corrected. As a result, the aberration R or the aberration change △R of the projection optical system 20 can be suppressed.

(Alignment processing S13)

Next, as shown in FIG. 2B , the substrate stage 50 is transported to the projection exposure position P1 via the transport control unit 90, and the aberration/position shift measurement stage 80 is transported to the retreat position P3.

When the substrate stage 50 is positioned at the projection exposure position P1, the photography control unit 100 controls the photography through the positioning symbol photography unit 40 by sending a photography command signal to the positioning symbol photography unit 40. The photography image signal S1 representing the image photographed by the positioning symbol photography unit 40 is input to the photography control unit 100. When the substrate 30 passes under the positioning symbol photography unit 40, the positioning symbol photography unit 40 photographs the coordinate position of each positioning symbol M31.

The aberration/position shift measuring unit 110 calculates the position shift relative to the reference position of the positioning symbol M31 in the photographic image, the tilt angle relative to the arrangement direction of each positioning symbol M31 serving as the reference, and measures the coordinate position, tilt, and magnification of the substrate 30. The position and posture of the substrate stage 50 are controlled in accordance with the measured coordinate position, tilt, and magnification of the substrate 30.

Here, the position and posture of the substrate stage 50 are controlled by adding the measured value of the position offset △Q of the positioning symbol photography unit 40 measured in the substrate exchange process and the aberration/position offset correction process S12. As a result, the position offset △Q of the positioning symbol photography unit 40 can be corrected.

As a result, the positioning accuracy of the substrate 30 that is caused by the positional deviation △Q of the positioning symbol photography unit 40 can be suppressed, and the positioning accuracy can be maintained at a high level.

(Exposure control processing S14)

Then, the transport control unit 90 controls the position and posture of the substrate stage 50 by sequentially projecting the projection exposure pattern PT2 onto each projection area AR2 on the substrate 30 based on the coordinate position, tilt, and magnification of the substrate 30 measured in the alignment process S13.

As a result, as shown in FIG5 , each projection area AR2 on the substrate 30 is sequentially exposed to the projection exposure pattern PT2.

(Substrate transport processing S15)

Next, as shown in FIG. 2A , the substrate stage 50 is transported to the substrate exchange position P2 via the transport control unit 90, and the aberration/position shift measurement stage 80 is transported to the projection exposure position P1.

Afterwards, if the mask 10 does not need to be exchanged (judgment N of S16), move to the above-mentioned substrate exchange process and aberration/position shift correction process S12. If the mask 10 needs to be exchanged (judgment Y of S16), the order is to return to the mask exchange and setting process S11.

In the above-mentioned embodiment, the substrate stage 50 and the aberration/position shift measuring stage 80 are separate objects, but the substrate stage 50 and the aberration/position shift measuring stage 80 may also be an integrated object.

FIG8A and FIG8B are figures corresponding to FIG2A and FIG2B respectively, showing a configuration example of a projection exposure device 200 in which a substrate stage 50 and an aberration/position shift measuring stage 80 are integrated into a pedestal 86 via a connecting member 85.

As shown in FIG. 8A , the transport control unit 90 controls the transport of the console 86 via the substrate transport unit 250 in such a manner that the substrate 30 is located at the substrate exchange position P2 and the reference mask 60 is located at the projection exposure position P1.

Furthermore, as shown in FIG. 8B , the transport control unit 90 controls the transport of the console 86 via the substrate transport unit 250 in such a manner that the substrate 30 is located at the projection exposure position P1 and the reference mask 60 is located at the retreat position P3.

By the implementation described above, when the substrate 30 is exchanged, the aberration R or aberration change △R of the projection optical system 20 is measured, and the position offset △Q of the positioning symbol photography unit 40 is measured. In this way, the exposure cycle of the substrate will not be affected, and the aberration R or aberration change △R of the projection optical system 20 can be suppressed, and the reduction of the alignment accuracy of the substrate 30 can be suppressed, and the alignment accuracy can be maintained at a high precision. Therefore, by this implementation, a projection exposure device 200 suitable for the market can be provided for exposure of substrates that require a shortened production cycle of substrate exposure and a high-resolution exposure pattern image, such as high-density packaging substrates.

10: Mask 20: Projection optical system 30: Substrate 40: Alignment mask photography unit 50: Substrate stage 60: Reference mask 80: Aberration/position shift measurement stage 170: Stage 200: Projection exposure device 210: Light box 211: Light source 220: Mask shield projection optical system 221: Shield 230: Mask stage 250: Substrate transport unit 260: Substrate exchange unit 261: Suction pad 270: Mask warehouse 280: Multi-joint robot for mask transport 281: Hand 290: Vibration reduction device

Claims (3)

A projection exposure device projects a pattern of a mask onto a substrate transported to a projection exposure position by a projection optical system, forms a mask side aberration detection symbol for detecting aberration or aberration change of the projection optical system on the mask, and forms a positioning symbol on the substrate. The projection exposure device comprises: A positioning symbol photographing unit, which photographs the positioning symbol on the substrate when the substrate is transported to the projection exposure position; A substrate stage, which carries the substrate; A substrate exchange unit, which exchanges the substrate on the substrate stage when the substrate stage is transported to the substrate exchange position; The aberration/position shift measuring stage is equipped with a reference mask and an aberration detection symbol photographing unit. The reference mask forms a reference mask side aberration detection symbols useful for detecting aberration or aberration change of the projection optical system, and forms position shift detection symbols useful for measuring position shift relative to the reference position of the positioning symbol photographing unit. The aberration detection symbol photographing unit clamps the reference mask and moves the reference mask from the projection optical system to the projection optical system. The aberration detection symbol on the mask side and the aberration detection symbol on the reference mask side are photographed on the opposite side of the optical system, wherein the aberration detection symbol on the reference mask side and the position offset detection symbol are respectively formed at a preset position on the reference mask in a photographable manner through the aberration detection symbol photographing unit and the positioning symbol photographing unit when the aberration/position offset measuring stage is positioned at the projection exposure position; A transport control unit, which controls the transport of the substrate stage and the aberration/position offset measuring stage by alternately positioning the substrate stage at the substrate exchange position and the aberration/position offset measuring stage at the first control position of the projection exposure position, and the substrate stage at the projection exposure position and the aberration/position offset measuring stage at the second control position of the retreat position; and The photography control unit, when the substrate stage and the aberration/position offset measuring stage are located at the first control position via the transport control unit, the position offset detection symbol on the reference mask is photographed via the positioning symbol photography unit, and the mask side aberration detection symbol and the reference mask side aberration detection symbol on the reference mask are photographed via the aberration detection symbol photography unit, and when the substrate stage and the aberration/position offset measuring stage are located at the second control position via the transport control unit, the positioning symbol photography unit photographs the positioning symbol on the substrate, thereby controlling the photography of the positioning symbol photography unit and the aberration detection symbol photography unit, When the transport control unit places the substrate stage and the aberration/position offset measuring stage at the first control position, the substrate mounted on the substrate stage is exchanged by the substrate exchange unit. The projection exposure device as described in claim 1, wherein at the substrate exchange position, each time the substrate mounted on the substrate stage is exchanged, photography control is performed by the photography control unit. A projection exposure device as described in claim 2, wherein at the substrate exchange position, each time the substrate mounted on the substrate table is exchanged, the position offset of the positioning symbol photography unit is corrected based on the result of the photography through the photography control unit, and the aberration or aberration change of the projection optical system is corrected.