JP2000208391A - Exposure apparatus and method, and device manufacturing method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To achieve the same focus accuracy as in the case where focus correction driving is performed immediately before stopping at the next exposure position. SOLUTION: Step driving means 3, 12, 13 for repeating step movement and positioning of the substrate in a direction perpendicular to the optical axis of the projection optical system so that respective exposure regions on the substrate 2 are sequentially located below the projection optical system 1. Detecting means 4 to 11 and 14 for detecting at least one of the position and the inclination of the substrate surface under the projection optical system in the optical axis direction, and based on the detection result, each exposure area is located on the focal plane of the projection optical system. An exposure apparatus that includes correction driving units 3, 12, and 13 that corrects and drives the substrate so that the substrate is positioned, and performs the correction driving during the step movement in an exposure apparatus that performs exposure of the substrate according to various job data that defines processing for the substrate Storage means for storing a predetermined offset value for each exposure area of the substrate for each job, wherein the detection means detects during the step movement, The stage performs correction driving during the step movement based on the detection result and the offset value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type exposure apparatus and method for manufacturing semiconductor circuit elements such as ICs, LSIs and VLSIs, and a device manufacturing method using the same. The present invention relates to an apparatus provided with a function of learning an offset value for driving correction in a driving operation.

[0002]

2. Description of the Related Art Generally, in a projection type semiconductor manufacturing apparatus, when a stage holding a substrate to be exposed such as a wafer moves to the next exposure position, focus correction driving is required. Conventionally, this focus correction drive takes into account the change in the attitude of the measurement surface due to the deceleration G of the stage and the influence during movement of the stage such as the sensor being fooled by the difference in the pattern surface from the exposure position. Implemented immediately before stopping.

In the above prior art, when the stage moves to the next exposure position, higher focus accuracy is required in the focus correction drive.

Further, in order to execute the auto-focusing process while the stage is moving to the next exposure position, the sensor is tricked by a change in the attitude of the measurement surface due to the stage deceleration G or a difference in the pattern surface from the exposure position. And so on. Therefore, conventionally, the measurement offset of the moving measurement point is obtained and recorded on the first wafer, and these measurement offsets are used in the processing of the second and subsequent wafers. In the processing of the second and subsequent wafers, stage drive, moving measurement, and correction drive are performed in this order, and the optimum focus plane is detected using the measurement offset recorded in the first wafer.

[0005]

However, if focus correction drive is performed immediately before the exposure position as described above,
Throughput decreases. In addition, according to the technology of performing auto-focus processing while the stage is moving, if the attitude of the measurement surface changes with time due to the deceleration of the stage, the use of an offset measured on the first wafer may reduce focus accuracy. Problem.

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, an object of the present invention is to provide an exposure apparatus and method, and a device manufacturing method using the same, which perform focus correction driving during movement of a stage to a next exposure position. In order to realize a pre-reading auto-focus system to be performed, it is an object of the present invention to ensure the same focus accuracy as in the case of performing focus correction driving immediately before the stage stops at the next exposure position.

[0007]

According to the present invention, there is provided a projection optical system for projecting a pattern of an original onto each exposure area on a substrate and exposing the same, and a projection optical system provided under the projection optical system. Step driving means for repeating step movement and positioning of the substrate in a direction perpendicular to the optical axis of the projection optical system so that the respective exposure areas are sequentially positioned; and position and inclination of the surface of the substrate under the projection optical system in the optical axis direction. Detecting means for detecting at least one of the above, and correction driving means for correcting and driving the substrate based on the detection result so that each exposure area is located at the focal plane of the projection optical system, and defines processing for the substrate. In an exposure apparatus that performs exposure of a substrate according to data of various jobs to be performed, a predetermined offset value for each exposure region of the substrate to realize the correction drive during the step movement. A storage unit for storing the job in units of jobs, wherein the detection unit performs the detection during the step movement, and the correction driving unit performs the correction driving (the pre-reading auto-reading) during the step movement based on the detection result and the offset value. Focus).

Further, the exposure method of the present invention uses such an exposure apparatus, and sets an offset for each exposure area for each job so that each exposure area of the substrate to be exposed is positioned on the focal plane of the projection optical system. The exposure is performed while correcting and driving the substrate based on the value during the step movement. Also,
The device manufacturing method of the present invention is characterized by manufacturing a device by such an exposure method.

According to this, the correction drive for each exposure area is performed based on the detection result during each step movement and the offset value for each job for each exposure area. In this case, the same focus accuracy as in the case where the focus detection is performed and the correction drive is performed is guaranteed. Further, since the correction driving is performed during the step movement, the exposure is performed at a higher throughput than when the correction driving is performed immediately before stopping at the exposure position.

[0010]

In a preferred embodiment of the present invention, the storage means stores an offset value for each exposure area for each exposure area. The image processing apparatus further includes an update processing unit that updates the offset value in units of an exposure area. The update processing means performs detection (focus measurement) by the detection means when the exposure area is positioned substantially below the projection optical system after the correction driving during the step movement for each exposure area, and obtains a predetermined tolerance. If not, the offset value is updated using the detection result.

When the offset value does not exist in the storage means, a result of detection of the substrate surface by the detection means during the step movement of each exposure area, and thereafter, the exposure area is positioned substantially below the projection optical system. Then, the offset value is obtained based on the result of the detection of the substrate surface by the detection means, and this is stored in the storage means. Further, the update processing means, for each of the exposure areas, calculates a predetermined formula with respect to the offset value read from the storage means and the result of detection by the detection means when the exposure area is positioned substantially under the projection optical system. By applying this, an updated value of the offset value is obtained, and as this equation, a plurality of values are switched and used according to the contents of the exposure processing.

Further, the optical axis direction is the Z axis, and the inclination is an inclination around each of the X and Y axes perpendicular to the Z axis, and the offset value for each exposure area is a measurement of these values. This is for the focus measurement value which is a value.

According to this, the focus measurement value at the first predetermined position during the step movement to the next exposure position and the focus measurement value immediately before stopping at the next exposure position are held, and the difference between them is determined. X, Y, and Z drive correction offset values are stored, and each drive correction offset value is set in a job for each parameter (hereinafter, referred to as a job) relating to a substrate positioning process and an exposure process. The X-, Y-, and Z-drive correction offset values stored for each job are stored for all shots or for one shot (exposure area) at the time of execution of the prefetch autofocus processing. Based on the execution results, the drive correction offset values of X, Y, and Z are updated in all shots or in one shot units in job units, thereby enabling read-ahead. Offset learning function is implemented in autofocus systems.

Further, the above job includes an individual job (hereinafter, referred to as a patch job) which is a wafer job including only a special processing for a wafer (substrate) which performs the special processing, so that the pre-reading is performed. It is possible to increase the number of target jobs that can realize the autofocus system.

[0015]

FIG. 1 is a partial schematic view of a semiconductor exposure apparatus according to one embodiment of the present invention. This apparatus employs a look-ahead autofocus system having an offset learning function according to the present invention. In FIG. 1, reference numeral 1 denotes a reduction projection lens system, and AX denotes an optical axis of the reduction projection lens system 1. The reduction projection lens system 1 uses a reticle circuit pattern (not shown)
/ 5 is projected and the circuit pattern image is formed on the focal plane. Further, the optical axis AX is in a relationship parallel to the Z-axis direction in the figure. Reference numeral 2 denotes a wafer having a surface coated with a resist, and the same pattern was formed in the previous exposure step.
Many exposure regions (shots) are arranged. Reference numeral 3 denotes a stage on which the wafer 2 is placed. The wafer 2 is attracted to and fixed to the wafer stage 3. Wafer stage 3
Is composed of an X stage that moves in the X axis direction, a Y stage that moves in the Y axis direction, and a Z stage that rotates around an axis parallel to the Z axis direction and the X, Y, and Z axis directions. Also,
The X, Y, and Z axes are set to be orthogonal to each other. Accordingly, by driving the wafer stage 3, the position of the surface of the wafer 2 can be adjusted in the optical axis AX direction of the reduction projection lens system 1 and in the direction along a plane orthogonal to the optical axis AX, and further, the focal plane, that is, the circuit pattern The tilt with respect to the image can also be adjusted.

Reference numerals 4 to 11 denote components of a detection optical system provided for detecting the surface position and inclination of the wafer 2. 4
Reference numeral denotes a high-luminance illumination light source such as a light emitting diode or a semiconductor laser, and reference numeral 5 denotes an illumination lens. The light emitted from the light source 4 is converted into a parallel light beam by the illumination lens 5, becomes a plurality of light beams through the mask 6, enters the bending mirror 8 through the imaging lens 7, and is changed in direction by the bending mirror 8. , And is incident on the surface of the wafer 2. That is, the imaging lens 7
The folding mirror 8 forms a plurality of pinhole images of the mask 6 on the wafer 2. As shown in FIG. 2, the light beam passing through the plurality of pinholes illuminates five measurement points 71 to 75 including the central portion of the exposure area 100 of the wafer 2 and is reflected at each point. That is, a set of pinholes is formed by five masks 6, and five measurement points 7 including a central portion thereof are formed in the exposure area 100 as described later.
The light fluxes reflected by 1 to 75 change their directions by the bending mirror 9 and then enter via a detection lens 10 onto a position detection element 11 in which elements are two-dimensionally arranged. Here, the detection lens 10 forms an image of a pinhole of the mask 6 on the position detection element 11 in cooperation with the imaging lens 7, the bending mirror 8, the wafer 2, and the bending mirror 9. Therefore, the mask 6, the wafer 2, and the position detection element 11 are at optically conjugate positions with each other.

Although schematically shown in FIG. 1, when it is difficult to arrange optically, a plurality of position detecting elements 11 may be arranged corresponding to each pinhole. The position detecting element 11 is composed of a two-dimensional CCD or the like, and is capable of independently detecting the incident positions of a plurality of light beams through a plurality of pinholes on the light receiving surface of the position detecting element 11. . Wafer 2
Change in the optical axis AX direction with respect to the reduction projection lens system 1 can be detected as a shift of the incident positions of a plurality of light beams on the position detecting element 11,
The positions of the surface of the wafer 2 in the direction of the optical axis AX at the five measurement points 71 to 75 in 00 are output as signals from the position detecting element 11 via the surface position detecting device 14 to the control device 13.
Is input to

The displacement of the wafer stage 3 in the X-axis and Y-axis directions is measured by a known method using a reference mirror 15 and a laser interferometer 17 provided on the wafer stage 3, and indicates the amount of displacement of the wafer stage 3. Signal to laser interferometer 17
Is input to the control device 13 via a signal line. The movement of the wafer stage 3 is controlled by the stage driving device 12. Stage drive device 12 receives a command signal from control device 13 via a signal line, and servo-drives wafer stage 3 in response to this signal. The stage driving device 12 has a first driving unit and a second driving unit.
The position (x, y) and rotation (θ) of the wafer 2 in a plane orthogonal to the optical axis AX are adjusted by the driving means, and the position (z) and the inclination of the wafer 2 in the optical axis AX direction are adjusted by the second driving means. (Α, β). The surface position detecting device 14 detects the surface position of the wafer 2 based on an output signal (surface position data) from the position detecting element 11, and transfers the detection result to the control device 13. Based on this, the control device 13 activates the second driving means of the stage driving device 12 according to a predetermined command signal, and adjusts the position and the inclination of the wafer 2 in the direction of the optical axis AX.

Next, the focus detection position will be described. In the present embodiment, a moving measurement point used for calculating the correction drive amount and an offset calculation reference mainly for correcting the measurement value at this position so as to be equivalent to the measurement value at the exposure position. Of exposure position measurement points are set. First, the exposure position measurement points (measurement points 71 to 75) are shown in FIG.
Shown in The measurement point 71 is located substantially at the center of the region to be exposed 100 and crosses the optical axis AX at the exposure position. In addition, the remaining measurement points 72 to 75 are located at the periphery of the exposed area 100. As described above, the normal exposure position measurement point is uniquely determined for each sensor in all shots in the wafer. Therefore,
In the conventional positioning position at the exposure position,
When detecting the position in the height direction, the offset does not need to be changed for each shot.

Next, FIG. 3 shows an example of measurement points during movement when measuring during movement. In the drawing, 71 to 75 indicate measurement points after the stage has moved to the exposure position, and 81 to 85 indicate measurement points while the stage is moving. In the figure, the optical axis A
Measuring point 81 during movement instead of measuring point at position intersecting X
Shows a state in which is measured. That is, the wafer is step-moved from right to left in the figure, and for each of the measurement points 71 to 75, the positions measured during the movement are 81 to 81, respectively.
The position shifted to the left position on the chip, such as 85, is measured.

When measurement is performed during the step movement as described above, a surface having a step structure strictly different from the exposure position is measured at a position relative to the chip.
This means that even a shot layout including only 12 shots as shown in FIG. 4 has five different measurement points (left, right, upper right, upper left, upper), and a maximum of eight measurement points. You will have different types of measuring points while moving.
In addition to this, the change of the main body structure in the measurement section during movement is caused by the step movement every time from the relationship between the shot position (x, y) on the wafer and the deformation (α, β) of the posture at that time. Even when the posture deformation is the same (α, β), it is possible to manage as a displacement in the z direction obtained by multiplication with the shot position from the center as an offset for each shot in the same manner as the offset due to the step in the shot.

The offset value of this embodiment will be described. In the present description, the wafer stage 3
A wafer 2 with a pattern is supplied thereon, and the deviation of the optical axis AX of the wafer 2 from the reference arrangement of the wafer stage 3 is measured by the alignment mechanism, and the step is performed according to the grid of the shot arrangement transferred onto the wafer. Is calculated, and these measured values and calculated values are stored in the control device 13. This makes it possible to uniquely determine the offset at the exposure position depending on the step shape for each focus sensor. As described in Japanese Patent Publication No. Hei 6-52707, a method of measuring a focus offset depending on a step shape at each exposure sensor at an exposure position is to calculate a surface shape function by performing focus measurement on a sample shot using a first wafer. By calculating the focus offset at the exposure position, the offset of each sensor with respect to the image plane at the exposure position is calculated.

Next, a method of measuring the measurement offset of the measurement point during movement will be described. The basic idea is that the data of the inclination and height of the position to be exposed with respect to the exposure image plane calculated using the measurement values obtained at the measurement points during the movement include the positions shifted from the measurement points 71 to 75 at the exposure position. It includes two types of offsets: a measurement error caused by the measurement at 81 to 85 and a measurement error due to the deformation of the main body structure, and a correction value including the error (the correction value at the exposure position) The focus measurement value at the exposure position after performing the correction drive with the (focus offset) uses the point that the error can be measured as a residual as it is.

That is, the step movement to the next shot is started, and it is determined that the movement has reached a predetermined measurement point during movement (that is, a point to be measured determined from data of the laser interferometer 17 on the stage), and the position is determined. , The inclination and height data of the position to be exposed are calculated, and correction driving is performed using the second driving means of the wafer stage 3 using the data. In this case, since the reproducibility of the fluctuation mode of the pattern position and the main body deformation is important for the measured value at the point to be measured, the focus detection system has a configuration that can guarantee the synchronism, that is, the accumulation type detection. In the case of an element, it is important to reset the storage cycle in synchronization with the position to be detected. Further, even in the case of using a light beam sampling detection method for obtaining an average of a large number of measurements, a hardware timing notification method is required so as to guarantee synchronization with the position to be measured.

Next, the first and second wafer stages 3
Confirm that the positioning of the driving means is completed, perform focus measurement at the exposure position, and perform data correction on the exposed image plane at the exposure position. The correction data is the two measurement error amounts included in the measurement data of the moving measurement point, and the moving offset is calculated as the focus offset at the moving measurement point as data for each shot (i). Can be. The stage correction driving method to the moving exposure position is hereinafter referred to as pre-reading auto focus.

FIG. 5 is a flowchart showing the flow of the entire operation of the exposure sequence of the present apparatus, and FIG. 6 is a flowchart showing the flow of processing of one wafer. As shown in FIG. 5, when the exposure sequence starts,
The job is read, a reticle is set, and a wafer is loaded (steps S1 to S3). Next, the job n for explaining the detailed operation in FIG. 6 is executed (step S4), and it is confirmed whether or not the processing of all the patch jobs included in the job read in step S1 has been completed (step S5). .

If the result of this check is that all patch jobs have not been completed, the next patch job to be processed is read (step S6), and the flow returns to step S4 to execute job n. If all the patch jobs have been completed, the wafers subjected to the exposure processing are unloaded (step S7), and it is confirmed whether the processing has been completed for all the wafers to be processed by the jobs read in step S1.

As a result of this check, if the processing has not been completed for all the wafers, the process returns to step S3, the next wafer is loaded, and the processing is continued. If the processing has been completed for all wafers, the offset values for all shots currently held as offset values are stored together with other job parameters (step S8), and the sequence ends.

Next, the detailed operation of the job n (step S4) will be described with reference to FIG. In the job n, first, it is determined whether there is an offset learning value for the current shot number (step S4-1). If there is no offset learning value for the current shot number, learning processing of the offset value for the current shot number is performed (steps S4-2 to S4-5). At this time, the operation of the wafer stage 3 and the timing of focus measurement,
FIG. 7A shows the relationship between the focus measurement values. That is, as shown in FIG. 7A, the focus measurement is performed at a position 400 μm before the target position where the wafer stage 3 stops while the wafer stage 3 is moving to the next exposure position, and the focus measurement at this time is performed. Value (Xa, Ya, Za)
Is stored in the memory (step S4-2). Next, FIG.
As shown in (a), focus measurement is performed at a position 1 μm before the target position where the wafer stage 3 stops,
The focus measurement value (Xb, Yb, Zb) at this time is stored in the memory (step S4-3). Next, the correction drive of the wafer stage 3 is performed, and the drive of the wafer stage 3 to the exposure position ends (step S4-4). Further, the offset value of the prefetching autofocus system for the current shot number is calculated and stored in the memory (step S4-5), and the process proceeds to step S4-14. Equation 1 is used to calculate the offset value.

[0030]

(Equation 1) The equation 1 is obtained by calculating the focus measurement values (Xa, Y) stored in the memory in steps S4-2 and S4-3.
a, Za) and (Xb, Yb, Zb), and the offset value (X [p] [i], Y [p] [i], Z) of the prefetching autofocus system with respect to the current shot number.
[P] [i]). Here, p represents the patch job number, and i represents the current shot number.

Equation (1) is used to calculate an offset value when there is no offset value of the prefetching autofocus system for the current shot number of the first wafer or the like processed in the job, for example. In this equation, 400 μm from the target position where the wafer stage 3 stops
By taking the difference between the focus measurement value (Xa, Ya, Za) m before and the focus measurement value (Xb, Yb, Zb) 1 μm before the target position where the wafer stage 3 stops, the prefetch focus for the current shot number is obtained. System offset value (X [p] [i], Y [p]
[I], Z [p] [i]), and the calculated value is stored in the memory.

If it is determined in step S4-1 that there is an offset learning value for the current shot number, a prefetch autofocus process is performed for the current shot number (steps S4-6 to S4-1).
3). FIGS. 7B and 7C show the relationship between the operation of the wafer stage 3, the timing of focus measurement, and the focus measurement value at this time.

That is, first, the offset value (X [p]) of the prefetching autofocus for the current shot number.
[I], Y [p] [i], Z [p] [i]) are read (step S4-6). Next, as shown in FIG. 7B, focus measurement is performed at a position 400 μm before the target position where the wafer stage 3 stops while the wafer stage 3 is moving to the next exposure position (Step S4--).
7). Next, the correction driving of the wafer stage 3 is performed with the target being the position where the offset value read in step S4-6 is added to the focus measurement value measured in step S4-7 (step S4-8). next,
As shown in FIG. 7B, focus measurement is performed at a position 1 μm before the target position where the wafer stage 3 stops, and the focus measurement values (Xb, Yb, Zb) at this time are measured.
Is stored in the memory (step S4-9). Next, a tolerance check is performed to determine the validity of the focus offset value read in step S4-6 (step S4-10).

The tolerance check is performed in step S4-9.
It is determined by determining whether the focus measurement value stored in the step is within a preset tolerance value (here, ± 0.05 μm). As a result, when the offset value exceeds the tolerance value, as shown in FIG. 7C, the correction drive of the wafer stage 3 is performed so as to fall within the set tolerance value range, and the exposure position is adjusted. Then, the drive process of the wafer stage 3 is completed (step S4-11), and the offset value of the prefetching autofocus system for the current shot number is calculated and stored in the memory (step S4-11).
12), and proceed to step S4-14. Equation 2 is used to calculate the offset value.

[0035]

(Equation 2) Equation 2 is obtained by comparing the focus measurement values (Xb, Yb, Zb) stored in the memory in step S4-9 with the focus measurement values in step S4-9.
The offset value (X [p] [i], Y [p] [i], Z) for the current shot number read out at −6
[P] [i]) and the offset value (X [p] [i], Y [p] [i], Z [p] [i]) of the new look-ahead autofocus system with respect to the current shot number.
Is an expression for calculating. Here, p represents the patch job number, and i represents the current shot number.

If it is determined in step S4-10 that the offset value does not exceed the tolerance value, the offset value read in step S4-6 is used as the offset value of the prefetching autofocus system for the latest current shot number. The information is stored in the memory (step S4-13), and the process proceeds to step S-14.

In step S4-14, step S4-
5. Update the offset value and store in the memory the offset value of the look-ahead auto-focus system stored in the memory in S4-12 or S4-13 as the offset value of the look-ahead auto-focus system for the same shot number of the same wafer after the next time. I do. The updating process of the offset value can be performed by calculating using an equation such as Equation 3, Equation 4, and Equation 5.

[0038]

(Equation 3)

[0039]

(Equation 4)

[0040]

(Equation 5) Equation 3 is a method of calculating an offset value by averaging. This is when all offset values for wafers processed so far in the same job (total number of shots set in a job including a patch job for one wafer × the number of wafers processed so far) are stored. Z [p] [i] on the left side, which is an offset value for the shot number in the next wafer processing, is:
Offset values Z [n] [p] [i] calculated so far
Is divided by the number of wafers processed so far.

The advantage of the method of calculating the offset value by averaging as shown in Equation 3 is that when the number of wafers processed so far is large, a numerical value that is greatly different from other offset values among the offset values. Even if there is a (singular point), the accuracy of the offset value is guaranteed by taking an average with other normal numerical values. However, when the number of wafers to be processed is small, the entire offset value is pulled by the offset value of the singular point, and the accuracy of the offset value is not guaranteed. Further, as described above, in order to use the averaging formula, since offset values for all shots of the wafer processed so far must be stored, there is also a disadvantage that a large amount of memory is required.

Equation 4 is a method of calculating an offset value by a moving average. This method is used when, for example, the offset values for all shots set in a job including a patch job for m sheets, which is the minimum moving average point number, are stored. Z [p] [i] on the left side, which is the offset value for the number, is the offset used for calculating the offset value on the left side, based on the numerical value of the moving average point number m and the value of the number of wafers n processed so far. While changing the value of. For example, if the number of processed wafers is 10 (n
= 10), the moving average point number is 3 (m = 3), the patch job number is 1 (p = 1), and the current shot number is 16
The equation for calculating Z [1] [16] in the case of (i = 16) is as follows.

[0043]

(Equation 6) The advantage of the offset value calculation method using the moving average as in Equation 4 is that when calculating the latest offset value, only the latest offset value and the offset value set by the number of moving average points are always calculated. Since it is used in the equation, even if there is a singular point, the offset value including the singular point can be eliminated as the moving average process proceeds. However, when a singular point frequently appears, the offset value is always pulled down to the value of the singular point. Further, increasing the number of moving average points also has the disadvantage of increasing the amount of memory used accordingly.

Equation 5 is a method of calculating an offset value by a pseudo moving average. In this method, the offset value to be stored may be only the offset value of all shots for a job including a patch job for one wafer. In Equation 5, Z [p] [i] on the left side, which is the offset value for the next shot in the next wafer processing, is obtained by multiplying the number of processed wafers (n) so far by the offset value for the current shot number. The sum of the offset value (Z1) and the offset value (Z1) is divided by a value obtained by adding 1 to the number of processed wafers.

The advantage of using the pseudo-moving average equation as shown in equation (5) is that the offset value stored in the memory or the like need only be the offset value for all shots for one wafer as described above. That is, the amount of memory and the like can be reduced.

After updating and storing the offset value in this manner, the completion of positioning of the wafer stage 3 is confirmed, and the positioning of the wafer stage 3 for performing the exposure processing is completed (step S4-15). An exposure process is performed (Step S4-16). When the exposure processing is completed, it is determined whether the exposure processing for all shots set in the patch job or the job not including the patch job has been completed (step S4-17). As a result, when there is an unexposed shot, the process returns to step S4-1 to perform the processing of the next shot. When the exposure processing for all shots has been completed, the process proceeds to step S5 in FIG.

<Embodiment of Device Manufacturing Method> Next, an embodiment of a device manufacturing method using the above-described exposure apparatus will be described. FIG. 8 shows a flow of manufacturing micro devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, etc.). In step 1 (circuit design), a device pattern is designed. Step 2 is a process for making a mask on the basis of the designed pattern. On the other hand, in step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon or glass.
Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer. The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and includes an assembly process (dicing, bonding),
It includes steps such as a packaging step (chip encapsulation). In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 9 shows the wafer process (step 4).
The detailed flow of is shown. Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist processing), a resist is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus or exposure method to align and print the circuit pattern of the mask on a plurality of shot areas of the wafer.
Step 17 (development) develops the exposed wafer.
In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps,
Multiple circuit patterns are formed on the wafer.

By using the production method of this embodiment, a large-sized device, which has been conventionally difficult to produce, can be produced at low cost.

[0050]

As described above, according to the present invention, when performing pre-reading auto-focusing, it is possible to guarantee the same focus accuracy as when performing focus detection immediately before stopping at the exposure position and performing correction driving. it can.

That is, when the substrate is moved to the next exposure position, steps such as a change in the attitude of the measurement surface over time due to the deceleration G of the stage holding the substrate and a sensor fooled by a difference in the pattern surface from the exposure position. Since the influence during the movement can be canceled by the learning function, the precision in the pre-reading autofocus can be improved.

Further, since the focus correction drive can be performed during the step movement, the step time in shot units can be reduced, and the total throughput time can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a partial schematic view of a step-and-repeat semiconductor exposure apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an arrangement of exposure position measurement points set in a region to be exposed in the apparatus of FIG.

FIG. 3 is an explanatory diagram showing an arrangement of moving measurement points set in a region to be exposed in the apparatus of FIG. 1;

FIG. 4 is an explanatory diagram for explaining a correspondence between an exposure position arranged on a wafer and each measurement position and a state of step movement between shots.

FIG. 5 is a flowchart illustrating a series of operation sequence flows in the semiconductor exposure apparatus of FIG. 1;

6 is a flowchart illustrating a step-and-repeat processing sequence including a pre-reading autofocus system processing sequence according to the present invention in the series of operation sequence flows in FIG.

FIG. 7 shows a case where there is no offset learning value, there is an offset learning value, and the result of focus remeasurement is within ± 0.05 μm in the pre-reading autofocus system processing of the step-and-repeat processing sequence of FIG. FIG. 9 is an explanatory diagram for explaining a first predetermined position, a second predetermined position, and each focus measurement value when there is an offset learning value and a result of focus remeasurement is not within ± 0.05 μm.

FIG. 8 is a flowchart illustrating a device manufacturing method that can use the exposure apparatus of the present invention.

FIG. 9 is a detailed flowchart of a wafer process in FIG. 8;

[Explanation of symbols]

1: reduction projection lens system, 2: wafer, 3: stage,
4: Light source for illumination, 5: Lens for illumination, 6: Mask, 7:
Imaging lens, 8, 9: bending mirror, 10: detection lens, 11: position detection element, 12: stage driving device, 1
4: surface position detecting device, 13: control device, 15: reference mirror, 17: laser interferometer, 71 to 75: measurement point, 81 to 81
85: measuring point during movement, 100: exposure area, 101,
102: exposure area, AX: optical axis.

Claims (10)

[Claims] 1. A projection optical system for projecting a pattern of an original onto each exposure area on a substrate and exposing the same, and the projection optical system such that each exposure area on the substrate is sequentially positioned under the projection optical system. Step driving means for repeating step movement and positioning of the substrate in a direction perpendicular to the optical axis of the system, and detecting at least one of the position and inclination of the surface of the substrate under the projection optical system in the direction of the optical axis And a correction driving unit that corrects and drives the substrate so that each exposure area is located on the focal plane of the projection optical system based on the detection result. In an exposure apparatus for exposing a substrate according to data, a predetermined offset value for each exposure area of the substrate is used to implement the correction drive during the step movement. Storage means for storing in units;
The detection means performs the detection during the step movement, and the correction driving means performs the correction drive during the step movement based on the detection result and the offset value. Exposure equipment. 2. The exposure apparatus according to claim 1, wherein the storage unit stores an offset value for each of the exposure regions in units of exposure regions. 3. The exposure apparatus according to claim 1, wherein the job includes an individual job which is a job including only the special processing for the substrate on which the special processing is performed. 4. An apparatus according to claim 1, further comprising an update processing unit for updating said offset value on an exposure area basis.
4. The exposure apparatus according to claim 3. 5. The result of the detection performed by the detection unit when the exposure area is positioned substantially below the projection optical system after the correction drive during the step movement for each exposure area. 5. The exposure apparatus according to claim 4, wherein when the distance is not within a predetermined tolerance, the offset value is updated using the detection result. 6. When the offset value does not exist in the storage means, for each exposure area, the result obtained by the detection means detecting the substrate surface during the step movement is substantially equal to the result of the detection. Means for obtaining the offset value based on a result of the detection of the substrate surface by the detection means when positioned under the projection optical system, and storing the offset value in the storage means. Item 6. The exposure apparatus according to item 4 or 5. 7. The updating processing means according to claim 1, wherein, for each exposure area, an offset value read from said storage means and a result of detection by said detection means when the exposure area is positioned substantially below said projection optical system. On the other hand, a predetermined expression is applied to obtain an updated value of the offset value, and as this expression, a plurality of values are switched and used according to the contents of exposure processing. Exposure apparatus according to the above. 8. The optical axis direction is the Z axis, and the tilt is a tilt around each of the X and Y axes perpendicular to the Z axis, and the offset value for each exposure area is The exposure apparatus according to claim 1, wherein the exposure apparatus is for a focus measurement value that is a measurement value. 9. An offset value for each exposure area for each job so that each exposure area of a substrate to be exposed is located on a focal plane of a projection optical system using the exposure apparatus according to claim 1. An exposure method, wherein exposure is performed while correcting and driving the substrate during step movement based on the method. 10. A device manufacturing method, wherein a device is manufactured by the exposure method according to claim 9.