KR20020071726A - Exposure method and apparatus - Google Patents

Abstract

PURPOSE: To improve connection precision correctly when patterns are connected to each other on a substrate to complete a picture. CONSTITUTION: Patterns A, B are connected to each other on the substrate to form a desired pattern, and the desired pattern is exposed to light to be transferred to the substrate. This method includes a provisional exposure process by which a first mark MK different from the patterns A, B and the connected patterns A, B are exposed to light to be preliminarily transferred to the substrate, and a setting process for setting an amount of correction when the connected patterns A, B are exposed to light to be transferred to the substrate based on the relative position relation between the first mark MK and the patters A, B which are preliminarily transferred to the substrate.

Description

Exposure method and exposure apparatus {EXPOSURE METHOD AND APPARATUS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure method and an exposure apparatus for exposing a mask pattern onto a substrate in a manufacturing process such as a semiconductor device or a liquid crystal display device. In particular, a large area pattern is exposed by bonding portions of a plurality of divided patterns together on a substrate. The present invention relates to a very suitable exposure method and exposure apparatus for use in performing so-called screen synthesis.

Conventionally, in such an exposure apparatus, in order to cope with the enlargement of the photosensitive substrate to be exposed, the exposure region of the photosensitive substrate is divided into a plurality of unit regions (shots), and the exposure to each unit exposure region is repeated a plurality of times. Thus, a so-called screen synthesizing technique is used, in which a pattern having a desired large area is finally synthesized. When performing screen compositing, each unit exposure area is caused by a drawing error of the reticle for pattern projection, aberration of the projection optical system, positioning error of the stage for positioning the photosensitive substrate, and the like. A gap may arise in the pattern joined at a boundary position. Therefore, in order to prevent the occurrence of a gap in the pattern, screen composition may be performed by overlapping only a small amount of the boundary of each unit exposure area, that is, partially overlapping each unit exposure area.

In performing such screen compositing, the most important thing should be noted between the pattern of the screen compositing portion due to the manufacturing accuracy of the reticle or the lens aberration of the projection optical system, the positioning accuracy of the stage for positioning the sample such as the photosensitive substrate, and the movement accuracy. This is to ensure the screen bonding accuracy by reducing the deviation of the maximum. That is, in the screen composition as described above, a step may occur in the seam portion of the pattern due to the relative positional shift between two adjacent patterns, thereby deteriorating the characteristics of the manufacturing apparatus. In the semiconductor device or liquid crystal display device manufacturing, since the screen-synthesized single layer pattern is superimposed on a plurality of layers (usually 5 to 8 layers in liquid crystal panel production), the overlap error of the unit exposure area in each layer is increased. Discontinuity changes in the pattern seam. In this case, in particular, in an active matrix liquid crystal display device, the contrast discontinuously changes in the pattern joint portion, and the quality of the device is degraded.

In general, since it is known that the difference between the overlap accuracy between the shot and the shot is important for the screen bonding accuracy in the exposure layer after the second layer, for example, the alignment mark formed in the first layer is measured, and the measurement result is obtained from the measurement result. The offset of the reticle and the photosensitive substrate in the layer after the second layer may be obtained and corrected. That is, when performing bonding exposure in a 2nd layer (for example, a source-drain layer), since there exists a reference | standard called the alignment mark formed in the 1st layer (for example, a gate layer) which is a full layer, this alignment mark is turned off. By measuring with a sense such as Axis and ensuring that the patterns of the source and drain layers to be bonded overlap with the patterns of the corresponding gate layers, respectively, as a result, the pattern bonding in the second layer is performed with high precision.

Thus, although the bonding precision of the pattern after the 2nd layer depends on the bonding precision of the pattern in a 1st layer, in normal exposure processing, there is no reference | standard in a base when joining a screen in a 1st layer, and mechanical precision Or since exposure is performed depending on the manufacturing precision of a pattern, it is difficult to ensure a joining precision with high precision. On the other hand, conventionally, the joining precision in the 1st layer was ensured by the following two methods, for example.

(1) in process

As for the reticle manufacturing error or the lens aberration of the projection optical system, as shown in FIG. 10, when the desired panel pattern is screen synthesized by the patterns A to D, which are bonded at two sides, as shown in FIG. A plurality of special patterns, specifically, a plurality of two-dimensional marks, are arranged along the side to be bonded in the vicinity of the pattern A, and the positions of these marks are measured from the stage side on which the photosensitive substrate as the exposed object is mounted, and the design position of each mark. By performing statistical processing on the misalignment with the measurement result, the correction parameters (shift, rotation, magnification, etc.) were obtained so as to expose the pattern on the graticule in the most ideal lattice shape on the stage. Moreover, as a method of measuring the position of a mark from this stage side, the reference mark member which has a slit mark is provided in a stage, the detection light of the same wavelength as an exposure wavelength is irradiated from the lower side of a reference mark member, and a scan movement of a stage is carried out. While the detection light incident through the slit mark, the projection optical system, and the mark on the reticle is monitored by the light amount detector, so-called ISS (Image Slit Sensor) measurement or the like for measuring the position of the mark with respect to the stage coordinate system can be used.

And also about the patterns B-D, the mark was arrange | positioned along the side joined similarly to the pattern A, and the correction parameter was calculated | required so that each pattern B-D might be exposed to ideal grid shape by measuring the position of these marks. . In addition, about the positioning accuracy or the movement precision of the stage which positions the photosensitive board | substrate, screen bonding precision was maintained by ensuring an error as small as possible at the time of adjustment.

(2) test exposure

Before performing the process exposure, the screens are combined with the patterns A to D, and the bonding exposure of the desired pattern is performed, and the bonding portions are measured by a measuring device to find the position shift amount Z as shown in FIG. 12, and the position shift amount Z A method of inputting the offset as an offset into the reticle portion of the exposure control data in the process exposure during the process exposure.

However, the following problems exist in the conventional exposure method and exposure apparatus as described above.

In the technique of the above (1), the correction parameters are adjusted for reasons such as not measuring the patterns A to D actually transferred, not measuring the pattern after the exposure, and measuring the optical principle such as ISS measurement. Even if it exposes based on this, the error from a design value may arise in the pattern actually exposed. This can be considered for several reasons, for example, the error based on the measurement principle or the limit of reproducibility, the deformation of the photosensitive substrate depending on the process conditions, and the manufacturing error between the actual pattern and the measurement mark.

In addition, in the technique of the above (2), when screen composition is performed in the first layer as described above, since there is no standard in the base, it is difficult to strictly secure the bonding accuracy and, for example, exposure to the first layer. Even if a sensor for measuring the position of one pattern is separately provided and a method of exposing another pattern based on the position of the measured pattern is adopted, the normal pattern shape is for each layer, for example, in the X direction or Y. Since it often extends only in one direction of the direction, it is difficult to detect the position of one pattern in both directions of X and Y. Therefore, it is difficult to ensure the joining precision sufficiently about the direction (Y direction or X direction) of the side which cannot be measured.

For this reason, the technique of (1) and (2) was not necessarily sufficient as a method of securing the joining accuracy.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide an exposure method and an exposure apparatus that can accurately secure the bonding accuracy when bonding a pattern onto a substrate to perform screen composition.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows embodiment of this invention, and is a schematic block diagram of an exposure apparatus.

FIG. 2A is a plan view of a reticle having a mark used in the exposure method of the present invention, and FIG. 2B is a detail view of the mark.

3 is a plan view in which a plurality of patterns and marks are exposed on a substrate.

4A is a partially enlarged view of the gate pattern, and FIG. 4B is a partially enlarged view in which the gate pattern and the mark overlap.

Fig. 5 is a partially enlarged view of the gate pattern and the mark exposed with the dividing line therebetween;

6 is a diagram illustrating a relative positional relationship between an abnormal lattice and a pattern.

7 is a partially enlarged view in which marks and gate patterns showing different shapes overlap.

8 illustrates an exposure method of another mark.

9 is a flowchart showing an example of a manufacturing process of a liquid crystal display (semiconductor) device.

10 is a diagram illustrating that a plurality of patterns are bonded.

11 is a plan view showing a pattern and two-dimensional mark formed on the reticle;

12 is a diagram showing that deviation occurs in the bonded pattern.

<Description of the reference numerals for the main parts of the drawings>

A to D: Pattern

MK: mark (first mark)

P: Glass Plate (Plate, Substrate)

R: Reticle (mask)

9: exposure apparatus

23 control device (calibration device)

33: storage device

38: scanning line pattern (unit pattern)

39: gate electrode pattern (unit pattern)

In order to achieve the said objective, this invention employ | adopts the following structures corresponding to FIGS. 1-12 which showed embodiment.

The exposure method of this invention is the exposure method which bonds patterns A-D on the board | substrate P, and exposes a desired pattern, WHEREIN: The pattern joined with the 1st mark MK different from pattern A-D. The pattern bonded together based on the preliminary exposure process which exposes (A-D) to the board | substrate P, and the relative positional relationship of the 1st mark MK exposed to the board | substrate P and the patterns A-D ( It is characterized by including the setting process of setting the correction amount at the time of exposing A-D).

Moreover, the exposure apparatus of this invention is an exposure apparatus which bonds patterns A-D on the board | substrate P, and exposes a desired pattern, WHEREIN: The agent which differs from the pattern A-D exposed to the board | substrate P is exposed. The storage device 33 and the storage device 33 which store a correction amount when exposing the patterns A to D to be bonded based on the relative positional relationship between the marks AK and the patterns A to D bonded. The correction apparatus 23 which joins a pattern on the board | substrate P based on the correction amount memorize | stored in ()) is characterized by the above-mentioned.

Accordingly, in the exposure method and the exposure apparatus of the present invention, for example, the first mark MK is a two-dimensional mark extending in the X direction and the Y direction, and is exposed to the substrate P together with the patterns A to D. By measuring the exposed patterns A-D and the first marks MK, the bonding shift of the patterns A-D can be determined as a two-dimensional correction amount. Therefore, when the actual exposure is performed, the bonding accuracy can be sufficiently secured by joining the patterns in the state corrected by this correction amount. In the present invention, since the pattern to be actually transferred is used when obtaining the correction amount, the correction amount necessary for the actual exposure can be directly obtained.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of the exposure method and exposure apparatus of this invention is described with reference to FIGS.

Here, it demonstrates using the example at the time of carrying out the screen synthesis | combination of a plurality of reticle patterns by a grain equal magnification to the glass plate (henceforth simply a plate) for liquid crystal display device manufacture which is a photosensitive board | substrate by the exposure apparatus of a stepper system. In these drawings, the same components as those in Figs. 10 to 12 shown as conventional examples are denoted by the same reference numerals, and the description thereof is omitted.

1 is a schematic configuration diagram of an exposure apparatus 9 for a liquid crystal display device. The exposure apparatus 9 projects and exposes the pattern of the liquid crystal display device formed on the reticle (mask) R onto a plate (substrate) P coated with a photosensitive agent (resist). The light source 10 and the illumination optical system ( 11), the projection optical system 12, the reticle stage (mask stage) 13, and the plate stage (substrate stage) 14 is schematically configured. Here, the Z axis parallel to the optical axis of the projection optical system 12, the X axis parallel to the ground of FIG. 1 in a plane perpendicular to the optical axis, and the Y axis perpendicular to the ground of FIG. 1 in a plane perpendicular to the optical axis, respectively. It is assumed that it is set.

The light source 10 emits the beam B as exposure light, and is composed of an ultrahigh pressure mercury lamp or the like. The beam B emitted from the light source 10 enters the illumination optical system 11.

The illumination optical system 11 includes an optical integrator for uniformizing the shutter 15 for opening and closing the optical path of the beam B, the reflection mirrors 16 and 17, the wavelength selective filter 18, and the beam B. an integrator (such as a fly's eye lens) 19, a variable field stop 20, and a condenser optical system 21. The shutter 15 is driven by the control device (calibration device) 23 through the shutter driver 22 to drive the light path of the beam B to open and close. The wavelength B (g-line or h-line, i-line) required for the exposure of the beam B incident on the illumination optical system 11 through the opening operation of the shutter 15 passes, and the optical Illuminance is made uniform by the integrator 19. The beam B with uniform illuminance passes through the beam splitter 24 and is then condensed by the condenser optical system 21 and overlaps the illumination area on the reticle R defined by the opening of the variable field stop 20. To the enemy. The opening position and the size of the variable field stop 20 are controlled by the control device 23 through a blind driver (not shown).

The reticle stage 13 holds the reticle R, and can be moved in two dimensions on the XY coordinate system by the reticle stage drive system 25. Moreover, the reticle alignment system 26a, 26b which is a photoelectric sensor is arrange | positioned above the reticle stage 13. As shown in FIG. The reticle alignment systems 26a and 26b irradiate alignment light having the same wavelength as that of the beam B emitted from the light source 10, and receive the reflected light with a CCD camera to perform image processing. The exposure apparatus detects an alignment mark on the reticle R formed in a straight line shape by Cr or the like, and drives the reticle stage 13 through the reticle stage drive system 25 based on the detection result. (R) is aligned (positioned) at a predetermined position in the XY coordinate system.

The projection optical system 12 forms an image of the pattern present in the illumination region of the reticle R on the plate P. FIG. The pattern image is transferred onto the plate P by the photosensitive agent coated on the plate P. The imaging characteristic (magnification, etc.) of this projection optical system 12 is adjusted by control of the control apparatus 23.

The plate stage 14 holds the plate P, and is comprised so that the stage drive device 27 can move two-dimensionally on an XY coordinate system. The moving mirror 28 is provided on this plate stage 14. The position of the plate stage 14 (or further, the position of the plate P) is that the laser light emitted from the laser interferometer 29 is reflected by the moving mirror 28 and enters the laser interferometer 29. Therefore, accurate measurement is performed based on the interference between the reflected light and the incident light. The measurement result by this laser interferometer 29 is output to the control apparatus 23. In addition, for convenience of description, in FIG. 1, only the moving mirror 28 and the laser interferometer 29 for measuring the X-direction position of the plate stage 14 are shown, but the moving mirror and the laser interferometer for measuring the Y-direction position are shown. It is further provided.

The oblique incidence type autofocus system 30a, 30b is arrange | positioned between the projection optical system 12 and the plate stage 14, and the plate P surface is always made into the predetermined position of the optical axis direction of the projection optical system 12. Position is determined. In other words, the plate stage 14 is driven in the Z direction so that the exposed surface of the plate P coincides with the focal plane of the projection optical system 12.

Moreover, on the plate stage 14, the disk-shaped reference mark member 32 is provided in the position substantially coinciding with the to-be-exposed surface of the plate P with respect to the optical axis direction of the projection optical system 12. As shown in FIG. The reference mark member 32 is provided with a slit mark (not shown) of a rectangular opening. Then, a mirror 34 and a condenser lens 35 are provided below the reference mark member 32 in the plate stage 14, and the beam B (exposure light) transmitted as the detection light by the optical fiber 36 is The reference mark member 32 is illuminated from below through the condenser lens 35 and the mirror 34.

The image of the slit mark on the illuminated reference mark member 32 is back projected onto the reticle R through the projection optical system 12. The beam B having passed through the reticle R is incident on the beam splitter 24 through the condenser optical system 21 and the reflection mirror 17. The beam B incident on the beam splitter 24 reflects here and enters the light amount sensor 37 which is a photoelectric sensor. The light quantity sensor 37 outputs an electric signal corresponding to the intensity of the incident beam B to the control device 23. In addition, the light quantity sensor 37 is arrange | positioned at the surface which is conjugate with the reticle R. As shown in FIG.

The control device 23 detects the mark position on the reticle using the signal output from the light quantity sensor 37 and the signal output from the laser interferometer 29 or the like, and simultaneously detects the mark position on the reticle with the position of the detected mark and the design position. By performing predetermined calculation processing (minimum square method or the like) using the shift amount, correction parameters such as rotation correction amount, XY shift correction amount, and XY magnification offset amount of the reticle R are calculated. And the control apparatus 23 positions the reticle R via the reticle stage drive system 25 based on the calculated correction parameter, and adjusts the imaging characteristic of the projection optical system 12. As shown in FIG.

In addition, the control device 23 collectively controls the projection optical system 12, the shutter driver 22, the blind driver, the reticle stage drive system 25, and the stage drive device 27, and the plate stage 14. The plate P is moved two-dimensionally through the plate stage 14 while detecting the position of, thereby bonding the pattern of the reticle R on the plate P to expose the desired pattern. In addition, the control device 23 is provided with a storage device 33 that stores various exposure data (recipe) such as sequence parameters, correction parameters, and the like (see FIG. 1).

Next, the process (preliminary exposure process) performed before a process process is demonstrated. This preliminary exposure step is roughly divided into a pattern exposure step of exposing the gate pattern exposed by the process to the plate P, and a mark exposure step of exposing the mark MK to the plate P on which the gate pattern is exposed. Here, as shown in FIG. 10, it is assumed that patterns A-D are bonded to the 1st layer of the plate P, and the gate layer (gate pattern) is screen-synthesized.

As shown in Fig. 12, each pattern A to D has a scan line pattern (unit pattern) 38 extending in the X direction and a predetermined pitch LX (for example, a pitch of 100 mu m) along the scan line pattern 38. The plurality of gate electrode patterns (unit patterns) 39 arranged in the same manner have the same gate pattern arranged at a predetermined pitch (LY) in the Y-direction, and the dividing lines to which the patterns A to D are bonded are usually a scan line pattern. It is set to intersect. The gate pattern is formed on the reticle R in a so-called positive pattern in which a resist remains on the plate P by the gate pattern after the exposed plate P is developed.

In addition, the reticle RT used for test exposure is shown to Fig.2 (a).

As shown in Fig. 2A, a mark as a first mark which is substantially different from the gate pattern or other pattern (source drain pattern, etc.) formed on the plate P in the process processing at the center of the reticle RT. (MK) is formed. As shown in Fig. 2B, each mark MK extends in the Y direction to be used for position measurement in the X direction, and the X mark XM extends in the X direction and is used for position measurement in the Y direction. It consists of a Y mark (YM).

The array pitch PX of the X mark XM is set to 1 / n (n is a natural number) of the array pitch LX of the gate electrode pattern 39, where PX = LK (i.e., n = 1). In addition, the arrangement pitch PY of the Y mark YM is set to 1 / m (m is a natural number) of the arrangement pitch LY of the scan line pattern 38, where PY = LY (that is, m = 1). In addition, these marks MK are formed on the reticle R in a so-called negative pattern in which a resist is removed from the plate P by the mark MK shape after the exposed plate P is developed. .

In the pattern exposure step, the gate pattern is exposed to the first layer on the plate P by using the reticle R having the gate pattern. At this time, while replacing four reticles each having patterns A to D, as shown in FIG. 3, the patterns A to D in the dividing line DLY extending in the Y direction and the dividing line DLX extending in the X direction. The panel patterns are screen synthesized on the plate P by sequentially bonding and exposing them.

In addition, the drive of the variable field stop 20 is driven using a shape characteristic in which the gate pattern or the source drain pattern constituting the panel pattern is repeatedly arranged at a constant pitch, without using a plurality of reticles having patterns A to D, respectively. By adjusting, the order of changing the illumination area on one reticle for each pattern may be set. In this case, the number of reticles is reduced, and the reticle exchange time can be reduced, thereby contributing to the improvement of production efficiency.

Next, by setting the test exposure reticle RT on the reticle stage 13 and moving the plate stage 14 in sequence, the mark MK is moved along the center of the plate P and the dividing lines DLY and DLX. Four exposures are performed each time (a plurality of times in FIG. 3). In addition, in the case of exposing the mark MK using this reticle RT, it is preferable to carry out continuously after exposure of the gate pattern, without performing alignment with the plate P. FIG. Thereby, the error according to plate alignment arises, and it can prevent that error factors other than joining precision are included in a test exposure result.

In this mark exposure process, the mark MK is exposed on both sides of each pattern beyond the dividing line DLY (and / or DLX) in each exposure. That is, the mark MK is simultaneously exposed in one shot on both sides of the pattern bonded adjacently on the plate P. FIG. In addition, as shown in FIG.4 (a), each mark MK has the X mark XM in a gate pattern with respect to the gate pattern formed in the pattern exposure process as shown in FIG.4 (b). The Y mark YM is overlapped so as to be located at the center of the X direction of the gate electrode pattern 39, and to be located at the center of the Y direction of the scan line pattern 38 in the gate pattern.

Further, since the mark MK on the reticle R is disposed near the reticle center, i.e., near the optical axis of the projection optical system 12, the reticle attributable to magnification or rotation when projected through the projection optical system 12. It is the structure which can make the error of a component the smallest.

In this manner, when both of the gate pattern and the mark MK are exposed on the plate P in the preliminary exposure step, the plate P is developed. Here, since the gate pattern is a positive pattern, the resist on the plate P is caused by the beam B passing through a region other than the gate pattern on the reticle R, as shown in Fig. 4A, 40 other than the area | region corresponding to a gate pattern is exposed, and the area | region (pattern 38 and 39 part) corresponding to a gate pattern turns into an unexposed area | region. And since the mark MK is a negative pattern, it exposes on the patterns 38 and 39 which are unexposed areas, as shown to FIG. 4 (b). Therefore, even when the developing process is performed on the plate P after the preliminary exposure process, the mark MK is formed in the gate pattern (however, in FIG. 4B, the mark XM protrudes from the gate pattern). Both ends are removed by the development process). Moreover, if the latent image measurement is possible, it can transfer to the measurement process mentioned later immediately after a preliminary exposure process, without developing plate P. FIG.

After the preliminary exposure step, the relative positional relationship between the gate pattern transferred to the plate P and the mark MK is measured by, for example, an overlap measuring instrument. Specifically, as shown in FIG. 5, for example, the relative positional relationship between the gate pattern and the mark MK adjacent in the X direction with the dividing line DLY interposed therebetween on both the patterns A and B sides, respectively. Measure

Here, when both of the patterns A and B shown in FIG. 5 are accommodated in one window for edge detection, the array pitch LX (see FIG. 12) of the gate electrode pattern 39 is 300 µm in pixel pitch and 100 in RGB division. Since it is about micrometer, it is necessary to greatly reduce the detection magnification of the objective lens in a measuring instrument. However, lowering the detection magnification lowers the detection resolution and consequently lowers the measurement accuracy. Therefore, in this embodiment, by measuring the relative positional relationship between the gate pattern and the mark MK for each pattern A and B, only an area measurement of about several tens of micrometers is sufficient, and one window is in a state where the detection magnification of the objective lens is increased. Edge detection can be performed within.

Hereinafter, the relative position measurement will be described in detail.

For example, a gate pattern and a mark (MK) overlap deviation amounts, with respect to the X direction overlapping with the gate electrode patterns 39 and the X mark (XM) deviation between the amount OVL _X in Fig. 5 left shot (pattern A) from In the Y direction, the overlapping shift amount OVL _Y between the scan line pattern 38 and the Y mark YM is obtained. Similarly, the amount of overlapping deviation between the gate pattern and the mark MK in the right shot (pattern B) is the amount of overlapping deviation OVR _X between the gate electrode pattern 39 and the X mark XM in the X direction, and Y In the direction, the amount of overlapping deviation OVR _Y between the scan line pattern 38 and the Y mark YM is obtained.

Here, the mark MK is formed on one reticle RT, and since the mark position and the distance between the marks can be measured in advance, the position on the plate P is also highly reliable compared with the gate pattern. Therefore, the above-mentioned overlapping shift amount is based on the position of the mark MK, and can be regarded as the overlapping shift and the junction shift (bonding error) of the gate pattern with respect to this mark MK.

The bonding accuracy between the pattern A and the pattern B is expressed by the following equation using the measured amount of overlap deviation.

X direction: | OVL _X -OVR _X |

Y direction: | OVL _Y -OVR _Y | (One)

In this way, bonding precision in both the X and Y directions, which has been difficult in the past, can be easily obtained separately.

In addition, in order to obtain the joining precision between the patterns A and C which adjoin the Y direction instead of the joining precision between the patterns A and B mentioned above, although not shown in figure, the division line DLX is interposed between them. The relative positional relationship between the gate pattern adjacent to the Y direction and the mark MK is measured in both patterns A and C in the same order as described above. Then, the X-direction overlap shift amount (referred to as OVU _X ) and the Y-direction overlap shift amount (referred to as OVU _Y ) between the gate pattern and the mark MK in the upper shot (pattern A), and the lower shot (pattern C) By calculating the X-direction overlapping shift amount (referred to as OVD _X ) and the Y-direction overlapping shift amount (referred to as OVD _Y ) between the gate pattern and mark MK in Fig. 9), and using the following equation based on equation (1). , The joint accuracy between the patterns A and C can be obtained.

X direction: | OVU _X -OVD _X |

Y direction: | OVU _Y -OVD _Y |

In addition, the amount of overlapping shift | offset | difference of a gate pattern and the mark MK is measured also about another location in the same procedure as the above. And, for example, the correction amount at the time of exposing pattern A, ie, the correction parameter (shift (X, Y), rotation, magnification, etc.) at the time of exposing using reticle R which has pattern A, is shown in FIG. As shown in Fig. 6, the amount of overlapping deviation between the plurality of marks formed along the side where the pattern A is bonded and the gate pattern among the plurality of marks MK and the design value can be obtained by statistical calculation processing using a least square method or the like. . Similarly, the correction parameter at the time of exposing pattern B-D is calculated | required using the overlapping shift | deviation amount of the mark and gate pattern formed along the side by which each pattern is joined.

Since these correction parameters are calculated using the gate pattern actually exposed on the plate P, including the pattern error of the reticle R and the aberration of the projection optical system 12, the correction including these errors becomes possible. In this way, the correction parameters for each of the patterns A to D obtained in the measurement process are stored in the storage device 33.

When the preliminary exposure step and the measurement step are completed, the process proceeds to an exposure step (actual exposure step). When the reticle R used in the preliminary exposure process, for example, having the pattern A is conveyed onto the reticle stage 13 by a carrier system (not shown), the control device 23 firstly reticles R. Reticle marks (not shown) formed outside the above illumination region are measured by the reticle alignment systems 26a and 26b, and the reticle R itself is aligned through the reticle stage drive system 25.

Next, the control device 23 positions the reference mark member 32 and the plate P with the reticle R relative to the optical axis direction of the projection optical system 12 by using the autofocus system 30a, 30b. Fit in position.

Next, the control apparatus 23 reads the rotation correction amount, XY shift correction amount, and XY magnification offset amount of the reticle R previously obtained from the storage device 33 in the setting step, and reticle stage 13 based on these correction parameters. At the same time, the reticle R is positioned and the imaging characteristics of the projection optical system 12 are adjusted. Thereby, as shown in FIG. 6, the pattern A of the reticle R which the shift | deviation generate | occur | produced with respect to the abnormal grating K is correct | amended.

When the alignment with respect to the reticle R is completed, the plate stage 14 is driven through the stage driving device 27 so that the area on the plate P to which the pattern A should be exposed is positioned in the shot area, and the beam ( B) is illuminated by reticle R to expose pattern A, which is part of the gate pattern, to the first layer on plate P. FIG. Thereafter, alignment is performed using the correction parameters read from the storage device 33 with respect to each reticle having the patterns B to D in the same order as the pattern A, and after positioning the plate P, the respective patterns B to D By exposing the surface, the panel pattern on which the patterns A to D are bonded is synthesized on the plate P.

By this screen composition, each of the patterns A to D becomes as if it overlaps with the mark MK formed in the 0th layer on the plate P with high precision, and with each 0 layer of each of the patterns A to D As the superimposition is performed with high accuracy, the joining accuracy of the patterns A to D is consequently improved.

And the pattern (source-drain pattern etc.) exposed after the 2nd layer on the plate P is replaced with the reticle which has the said pattern, and uses the plate alignment mark formed at the time of exposing the gate pattern of the 1st layer. By adjusting the alignment of the reticle and the imaging characteristics of the projection optical system 12, the reticle is superimposed on the gate pattern with high accuracy. In addition, in order to superimpose the second layer after the first layer with high accuracy, in addition to the method of using plate alignment, the above test exposure is also performed on the pattern exposed after the second layer, and the pattern is bonded and exposed in advance. The method of obtaining the correction parameter at the time can also be adopted.

As described above, in the exposure method and the exposure apparatus of the present embodiment, the gate pattern and the mark MK transferred in the process in the preliminary exposure step are exposed on the plate P, and the gate pattern is based on the overlapping shift amount thereof. Since the correction parameter at the time of exposing light is previously obtained, the 0th layer exists on plate P, and it exposes with the precision equivalent to the case where it exposes by overlaying a gate pattern on this 0th layer, As a result, a plate ( P) When joining a plurality of patterns to the above first layer, it is possible to sufficiently secure the joining accuracy.

In addition, in this embodiment, by making the mark MK into a two-dimensional mark and exposing the mark MK for each pattern to be bonded, the bonding error can be detected in both the X direction and the Y direction. Therefore, in the preliminary exposure step, not only the correction parameter for each pattern, but also the relative bonding accuracy between the patterns to be bonded can be obtained. As a result, in the present embodiment, by using the correction parameter, the alignment accuracy is pursued for each of the patterns A to D, and consequently, the joining precision is improved. However, for example, relative to the pattern A based on the pattern A, It is also possible to correct and join the correction parameters of the patterns B to D by using the joining precision.

In the present embodiment, the gate pattern is a positive pattern, the mark MK is a negative pattern, and the arrangement pitch of the marks MK is the arrangement pitch of the scan line pattern 38 and the gate electrode pattern 39. Since these are overlapped and exposed, the range at the time of measuring the overlap deviation can be reduced to about tens of micrometers. Therefore, edge detection can be performed in a state where the detection magnification of the measuring instrument is made high, and it is not affected by the deterioration of the measurement accuracy due to the objective lens magnification, which enables more accurate detection and does not procure a new measuring instrument separately. It is possible to use a superposition measuring device or the like which has conventionally been used, and can contribute to high precision and cost reduction. In addition, in this embodiment, since the mark MK on the reticle RT is disposed near the center of the reticle, the error of the reticle component due to the magnification or rotation at the time of projection can be minimized, and more accurate Joining of the figure can be realized.

In addition, in the said embodiment, although the mark MK as a 1st mark was formed in the reticle RT different from the reticle R in which the gate pattern was formed, it is not limited to this, For example, a gate The first mark may be formed directly on the reticle R having the pattern. In this case, the first mark is arranged in a corner portion separated from the pattern A, but if the reticle stage 13 is movable, the first mark is positioned near the optical axis of the projection optical system 12. By carrying out the test exposure at, the error of the reticle component due to the magnification or rotation at the time of projection is the smallest, which is preferable.

In addition, in the said embodiment, although the gate pattern was a positive pattern and the mark MK which is a 1st mark was set as a negative pattern, on the contrary, a gate pattern may be a negative pattern and a 1st mark may be a positive pattern. In addition, the shape of a 1st mark is not limited to what was mentioned above, If both X direction and Y direction can detect edge, as shown in FIG. 7, the mark MK which shows L shape may be sufficient.

In addition, in the said embodiment, although it set as the structure which exposes four marks MK on the plate P four by one exposure in a preliminary exposure process, for example, by controlling the drive of the variable-view aperture 20, As shown in FIG. 8, the mark MK may be individually exposed to two parts over the pattern to be bonded. In addition, in the said embodiment, although the patterns A-D to be bonded were demonstrated as having the same gate pattern, it is not limited to this, It is applicable also when joining mutually different patterns.

As the substrate of the present embodiment, not only the glass plate P for the liquid crystal display device, but also the semiconductor wafer for the semiconductor device, the ceramic wafer for the thin film magnetic head, the original plate of the mask or reticle used in the exposure apparatus (synthetic quartz) , Silicon wafer) and the like.

As the exposure apparatus 9, the exposure apparatus (stepper) of the step-and-repeat method which exposes the pattern of the reticle R in the state which stopped the reticle R and the plate P, and moves the plate P step by step. In addition, the present invention can also be applied to a step-and-scan scanning type exposure apparatus (scanning stepper; USP5, 473, 410) in which the reticle R and the plate P are synchronously moved to scan-expose the pattern of the reticle R.

As the kind of exposure apparatus 9, it is not limited to the exposure apparatus for liquid crystal display device manufacture which exposes a liquid crystal display device pattern to plate P, but the exposure apparatus for semiconductor device manufacture which exposes a semiconductor device pattern to a wafer, and thin film magnetic It can be widely applied to an exposure apparatus for manufacturing a head, an imaging device (CCD), a reticle, or the like.

In addition, as the light source 10 of the beam B, a bright line (g line (436 nm), h line (404.7 nm), i line (365 nm)) generated from an ultra-high pressure mercury lamp, KrF excimer laser ( 248 nm), ArF excimer laser (193 nm), F ₂ laser (157 nm), as well as charged particle beams such as X-rays or electron beams. For example, when using an electron beam, lanthanum hexaborite (LaB ₆ ) and tantalum (Ta) of a hot electron radiation can be used as an electron gun. In addition, when using an electron beam, it can also be set as the structure using reticle R, and can also be set as the structure which forms a pattern directly on a glass substrate, without using reticle R. FIG. Moreover, high frequency, such as a YAG laser or a semiconductor laser, can also be used.

The magnification of the projection optical system 12 may be any of the reduction system and the magnification system as well as the equal magnification system. As the projection optical system 12, when using far ultraviolet rays such as an excimer laser, a material that transmits far ultraviolet rays such as quartz or fluorite is used as the base material, and when F ₂ laser or X-ray is used, reflection is used. An optical system of a refractometer or a refractometer is used (the reticle R also uses a reflective type). When using an electron beam, it is preferable to use an electron optical system composed of an electron lens and a deflector as the optical system. In addition, the optical path through which the electron beam passes must be in a vacuum state. Moreover, it is applicable also to the proximity exposure apparatus which exposes the pattern of the reticle R by making reticle R and plate P adjoin without using the projection optical system 12. FIG. In addition, in the said embodiment, although the projection optical system 12 was shown as a single lens, it may also be the so-called multi-lens projection optical system which has arrange | positioned multiple projection lenses so that a projection area may overlap each other.

When using a linear motor (see USP5,623,853 or USP5,528,118) for the plate stage 14 or the reticle stage 13, either an air floating type using an air bearing and a magnetic floating type using Lorentz force or resistance force You may use it. In addition, each stage 13 and 14 may be a type which moves along a guide, or may be a guideless type which does not have a guide.

As a driving mechanism of each stage 13 and 14, the magnet unit (permanent magnet) which arrange | positioned a magnet in two dimensions, and the armature unit which arrange | positioned the coil in two dimensions are opposed, and each stage 13 and 14 is moved by an electromagnetic force. It is also possible to use a planar motor for driving. In this case, one of the magnet unit and the armature unit is preferably connected to the stages 13 and 14, and the other of the magnet unit and the armature unit is provided on the moving surface side (base) of the stages 13 and 14.

As described in Japanese Patent Laid-Open No. 8-166475 (USP5,528,118), the reaction force generated by the movement of the plate stage 14 is not transmitted to the projection optical system 12. You can also escape to the floor (ground). The present invention is also applicable to an exposure apparatus having such a structure.

As described in JP-A-8-330224 (US S / N 08 / 416,558), the reaction force generated by the movement of the reticle stage 13 is not transmitted to the projection optical system 12. It is also possible to mechanically escape to the floor (ground) using. The present invention is also applicable to an exposure apparatus having such a structure.

As described above, the exposure apparatus 9, which is the substrate processing apparatus of the present embodiment, is assembled by assembling various subsystems including each component described in the claims of the present application so as to maintain predetermined mechanical precision, electrical precision, and optical precision. Are manufactured. In order to secure these various accuracy, before and after this assembly, adjustment for achieving optical precision for various optical systems, adjustment for achieving mechanical precision for various mechanical systems, and electrical precision for various electric systems are performed. Adjustment is performed. The assembling process from the various subsystems to the exposure apparatus includes mechanical connection of various subsystems, wiring connection of electric circuits, piping connection of pneumatic circuits, and the like. Prior to the assembling process from these various subsystems to the exposure apparatus, there is an assembling process for each subsystem. When the assembly process to the exposure apparatus of various subsystems is complete | finished, comprehensive adjustment is performed and the various precision as the whole exposure apparatus is ensured. In addition, it is preferable to manufacture an exposure apparatus in the clean room where temperature, cleanliness, etc. were managed.

As shown in FIG. 9, a device such as a liquid crystal display device or a semiconductor device includes step 201 of performing a function and performance design such as a liquid crystal display device, and step 202 of manufacturing a reticle R (mask) based on this design step. The pattern of the reticle R to the glass plate P (or the wafer) by the exposure apparatus 9 of the above-described embodiment of step 203 of manufacturing the wafer from the glass plate P or the silicon material with quartz or the like. It manufactures through the step 204 which exposes, the step of assembling a liquid crystal display device, etc. (in the case of a wafer, including a dicing process, a bonding process, a package process) 205, an inspection step 206, etc.

As described above, in the exposure method according to claim 1, after exposing the bonded pattern and the first mark to the substrate, the exposed pattern is exposed based on the relative positional relationship between the first mark and the pattern. The procedure for setting the correction amount at the time is performed.

Thereby, in this exposure method, even when joining a some pattern on a board | substrate, the effect of fully ensuring bonding precision is exhibited.

The exposure method according to claim 2 of the claims is in the order of exposing the first mark for each pattern to be joined.

As a result, in this exposure method, not only the correction parameters for each pattern but also the relative bonding accuracy between the patterns to be joined can be obtained, the correction parameters of the other patterns are corrected using the relative bonding accuracy with respect to the reference pattern. It also shows the effect that it is possible to join by joining.

The exposure method according to claim 3 of the claims has a configuration in which the first mark is arranged corresponding to the arrangement pitch of the unit pattern.

Thereby, in this exposure method, the range at which the amount of overlapping deviation between the first mark and the unit pattern is measured can be reduced to about several tens of micrometers, and the edge detection is performed while the detection magnification in the measuring instrument is increased. Therefore, it is possible to obtain an effect that the detection can be performed with higher accuracy without being affected by the deterioration of the measurement accuracy due to the objective lens magnification.

The exposure method according to claim 4 of the claims is in the order of exposing the first mark and the pattern by overlapping them.

Thereby, in this exposure method, the range at which the amount of overlapping deviation between the first mark and the unit pattern is measured can be reduced to about several tens of micrometers, and the edge detection is performed while the detection magnification in the measuring instrument is increased. Therefore, it is possible to obtain an effect that the detection can be performed with higher accuracy without being affected by the deterioration of the measurement accuracy due to the objective lens magnification.

The exposure method according to claim 5 of the claims has a configuration in which the pattern is either one of a negative pattern and a positive pattern, and the first mark is either of the negative pattern and the positive pattern.

Thereby, in this exposure method, the range at which the amount of overlapping deviation between the first mark and the unit pattern is measured can be reduced to about several tens of micrometers, and the edge detection is performed while the detection magnification in the measuring instrument is increased. Therefore, it is possible to obtain an effect that the detection can be performed with higher accuracy without being affected by the deterioration of the measurement accuracy due to the objective lens magnification.

The exposure method according to claim 6 in the claims is in the order in which the pattern is formed in the first layer of the substrate.

Thereby, in this exposure method, even when the pattern used as a reference | standard is not formed in a board | substrate, the effect of fully ensuring the bonding precision at the time of joining a some pattern is exhibited.

In the exposure method according to claim 7 of the claims, the first mark is formed in the center of the mask.

Thereby, in this exposure method, the error of the mask component resulting from the magnification or rotation when a 1st mark is projected can be made the smallest, and the effect which can implement | achieve a high precision bonding is exhibited.

The exposure method according to claim 8 of the claims is configured such that the pattern to be bonded is the same pattern.

Thereby, in this exposure method, even when bonding the same pattern on a board | substrate, the effect of fully ensuring bonding precision is exhibited.

The exposure apparatus according to claim 9 of the claims stores the correction amount when exposing the pattern to be bonded based on the relative positional relationship between the first mark and the pattern, and bonds the pattern onto the substrate based on the stored correction amount. It becomes the structure to say.

Thereby, in this exposure apparatus, when joining a some pattern on a board | substrate, the effect of fully ensuring bonding precision is exhibited.

Claims (9)

In the exposure method which exposes a desired pattern by bonding a pattern on a board | substrate, A preliminary exposure step of exposing the first mark different from the pattern and the pattern to be bonded to the substrate; A setting step of setting a correction amount when the pattern to be bonded is exposed based on a relative positional relationship between the first mark exposed on the substrate and the pattern Exposure method comprising a. The method of claim 1, The said 1st mark is exposed for every said joined pattern, The exposure method characterized by the above-mentioned. The method of claim 2, The pattern has a unit pattern arranged at a predetermined pitch, And the first mark is arranged corresponding to the predetermined pitch. The method of claim 1, An exposure method characterized by overlapping the first mark and the pattern. The method of claim 1, The pattern is either one of a negative pattern and a positive pattern, The first mark is any one of the negative pattern and the positive pattern. The method of claim 1, A plurality of patterns are formed on the substrate, The pattern is an exposure method, characterized in that the pattern formed in the first layer. The method of claim 1, The said 1st mark is formed in the center of a mask, The exposure method characterized by the above-mentioned. The method of claim 1, The said joined pattern is the same pattern, The exposure method characterized by the above-mentioned. In the exposure apparatus which bonds a pattern on a board | substrate, and exposes a desired pattern, A storage device that stores a correction amount when exposing the bonded pattern based on a relative positional relationship between the first mark different from the pattern exposed on the substrate and the bonded pattern; A correction device for bonding the pattern on the substrate based on the correction amount stored in the storage device Exposure apparatus characterized by including the.