JP2001274068A - Alignment method, manufacturing method of device, alignment device and aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a wasteful time generated by a sample shot which was decided to be unusable as the result of a measurement of the position of each sample shot. SOLUTION: A measurement of the position of an alignment mark to each sample shot previously selected from among shots on a substrate is made, and an alignment of the substrate with the shots is performed on the basis of the result of the measurement. Before a measurement of the position of each sample shot is made, whether the sample shot is suited to be the object of a measurement of its position or not is decided on the basis (Step S201) of the result of the previous measurement of the position of the sample shot (Step S202 to S204).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alignment method, a device manufacturing method, an alignment apparatus, and an exposure apparatus. More particularly, the present invention relates to alignment of a substrate by measuring alignment marks of a sample shot, and a circuit pattern on the substrate. The present invention relates to a device suitably applied for manufacturing devices such as semiconductor elements and liquid crystal elements by printing.

[0002]

2. Description of the Related Art Generally, when a pattern on a reticle is overprinted on a pattern printed on a wafer, alignment marks are measured for a plurality of sample shots selected in advance, and a positional shift is calculated. The position shift of the entire shot layout is calculated, the exposure position is corrected, and the overlay exposure is performed.

However, when measuring an alignment mark, there is a sample shot in which the measurement result cannot be used because the alignment mark cannot be measured due to a mark defect or the like, or the correct position cannot be measured.

Conventionally, a plurality of alternative sample shots to be used for measurement have been previously selected for each sample shot. For a sample shot for which the measurement result cannot be used, an alternative sample shot is assigned. I measure it.

[0005]

However, according to such prior art, when there is a sample shot in which the measurement result cannot be used because measurement cannot be performed due to a mark defect or the like, or when a correct position cannot be measured. However, there is a problem that the time for moving the stage to the position of the sample shot and the time for measuring the AA (auto alignment) of the sample shot are wasted, and the position measurement takes time.

The present invention has been made in consideration of the above-described problems of the related art, and eliminates useless time caused by a sample shot in which measurement results cannot be used in an alignment method, a device manufacturing method, an alignment apparatus, and an exposure apparatus. That is the task.

[0007]

In order to solve this problem, a first alignment method of the present invention measures the position of an alignment mark for each sample shot selected in advance from among shots on a substrate. In the positioning method for positioning the substrate based on the result, before performing position measurement on each sample shot, the position measurement target is determined based on the result of the position measurement performed previously on the sample shot. It is characterized by judging the suitability.

[0008] In a second positioning method, in the first positioning method, a result of position measurement as a basis for the determination is:
The alignment is performed on the same substrate as the substrate to be currently aligned.

In a third positioning method, in the first positioning method, a result of position measurement serving as a basis for the determination is:
The present invention is characterized in that the alignment is performed on the same type of substrate as the substrate to be currently aligned.

A fourth alignment method is the method according to the first or third alignment method, wherein a result of position measurement serving as a basis for the determination is determined for a first substrate of the same lot as a substrate to be currently aligned. It is characterized by being performed.

According to a fifth alignment method, in any one of the first to fourth alignment methods, the result of the position measurement serving as the basis for the determination is in the same step as the substrate to be currently aligned. It is performed on a substrate.

In a sixth alignment method, in any one of the first to fifth alignment methods, if it is determined that the object is not suitable for position measurement as a result of the determination, instead of the sample shot, It is characterized in that position measurement is performed for an alternative sample shot.

In a seventh positioning method, the position is measured for each sample shot in any one of the first to sixth positioning methods, and the result is stored for subsequent determination. It is characterized by doing.

Further, in the device manufacturing method of the present invention, a substrate is aligned with an original by any one of the alignment methods of the first to seventh aspects of the present invention. Exposing each shot position on the substrate sequentially.

Further, the positioning apparatus of the present invention is characterized in that it comprises means for positioning the substrate by any one of the first to seventh positioning methods of the present invention.

The exposure apparatus according to the present invention comprises: means for aligning the substrate with respect to the original plate by any one of the first to seventh alignment methods of the present invention; And an exposure means for sequentially exposing the pattern of the original plate at each shot position.

In the configuration of the present invention, when measuring the position of each sample shot for alignment of the substrate, before measuring the position of each sample shot, the position measurement of the position measurement previously performed on the sample shot is performed. Based on the result, it is determined whether the sample shot is suitable for position measurement. When it is determined that the sample shot is not suitable, the measurement is not performed for the sample shot, and the measurement of the alternative sample shot can be immediately performed. Therefore, the wasteful time is eliminated as compared with the related art in which the wasteful time is consumed by measuring the sample shot for which the measurement result cannot be used.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an exposure apparatus for manufacturing a semiconductor of a step-and-repeat type according to an embodiment of the present invention, a so-called stepper. In the figure, RT is a reticle on which a pattern PT for manufacturing a semiconductor element is formed, and LN is a reticle RT.
The upper pattern PT is transferred to the wafer W on the XYθ stage XYS.
A projection lens for reducing projection to a unit, a CU is a control unit for controlling the entire stepper, and a CS is a unit for inputting necessary information such as alignment data and exposure data to the control unit CU or storing it in a storage device such as an internal hard disk. It is a console to keep. The control unit CU includes a plurality of computers, a memory, an image processing device, an XYθ stage control device, and the like.

Reticle RT is a reticle stage RS that moves in the XYθ directions in accordance with a command from control unit CU.
Is held by suction. Reticle RT is a reticle alignment mark RAM used when aligning reticle RT with respect to projection lens LN in a predetermined positional relationship.
R, RAML, and reticle marks RMR, RML for transfer to the photochromic plate PHC. In this embodiment, the RMR and the RML are arranged at the same Y coordinate position on the reticle RT.

Reticle set marks RSMR, RSML
Is formed on a member fixed to the lens barrel of the projection lens LN so as to have a predetermined positional relationship with the projection lens LN. The alignment of the reticle RT with respect to the projection lens LN is performed by using the mark observation mirror AM with the mark RAMR and RSMR pair and the mark RAML and mark RSML pair.
The image is superimposed by the imaging device CM via the R and AML, and the reticle stage RS is moved so that the positional deviation detected from the image output at this time is within a predetermined allowable value. The mark observation mirrors AMR and AML can move in the XY directions according to a command from the control unit CU.

MX and MY are XYθ stages XYS XY
, A motor for rotating the XYθ stage XYS in the θ direction, and MRX, MRY for X
Mirror fixed to Yθ stage XYS, IFX,
IFY and IFθ are laser interferometers, and the XYθ stage XYS always monitors the position on the XYθ coordinates by the laser interferometers IFX, IFY, IFθ and the mirrors MRX, MRY, and controls the control unit CU by the motors MX, MY, Mθ. Move to the position specified by. The control unit CU keeps the laser interferometers IFX, IFY,
The XYθ stage XYS is held at a specified position based on the output of IFθ.

The wafer stage WS is an XYθ stage XY
This is a stage for holding a wafer that moves in the Z direction with respect to S. Wafer W is held by suction on wafer stage WS. The photochromic plate PHC is XY
is a flat plate coated with a photosensitive agent, for example, a spiropyran-based or spironaphthooxazine-based photochromic material, fixed on the θ stage XYS or on the wafer stage WS, and attached near the height of the imaging plane of the projection lens LN. ing.

The transmittance of the above-described photosensitive agent temporarily changes with respect to the light having the exposure wavelength from the exposure light source IL, and returns to the original transmittance with time. Therefore, the mark on the reticle RT can be transferred, and after a certain period of time, the transferred pattern disappears, and the mark can be transferred again.

The exposure light source IL is a light source for projecting and exposing the pattern PT on the reticle RT to the wafer W on the wafer stage WS via the projection lens LN. Further, by opening the mark exposure shutters SHR and SHL, the reticle mark R is placed on the photochromic plate PHC via the mark observation mirrors AMR and AML and the projection lens LN.
It is also used as a light source when projecting and exposing MR and RML.

The off-axis scope OS is a mark observation microscope having a focal plane at a Z position substantially equal to the projection lens LN. With the microscope OS, an image of the wafer W on the wafer stage WS or the mark transferred onto the photochromic plate PHC is captured. From the image output at this time, the captured mark is moved in the XY directions from the center of the off-axis scope OS. The deviation can be calculated by the control unit CU. Further, the off-axis scope OS can change the magnification, and can switch to a low magnification when measuring a pre-alignment mark, which will be described later, and detect the mark in a wide field of view.

FIG. 2 is an explanatory view of the XYθ stage XYS, and is a plan view of the stage as viewed from above (Z direction). The position of the XYθ stage XYS in the XY direction is the interferometer I
It is controlled by lengths Lx and Ly measured by FX and IFY. The position in the θ direction is determined by the difference between the lengths Ly and Lθ measured by the interferometers IFY and IFθ and the interferometer IF
The distance d between the laser beams Y and IFθ is calculated and controlled by the following equation. θ = (Ly−Lθ) / d

Θ is the reticle set mark RSMR, RS
It is assumed that the correction is made in advance to be 0 when the X-axis direction of the entire apparatus determined by the line connecting the MLs and the X-direction of the XYθ stage XYS match. The method of obtaining the correction amount is disclosed in Japanese Patent Application No. 4-351487.

FIG. 3 is a flowchart showing a procedure for transferring a new pattern on a wafer W on which a pattern has already been formed, and the sequence will be described later. FIG. 4 is an explanatory view of an alignment mark and a sample shot on a wafer. FIG. 5 is a diagram showing position correction of a wafer after alignment. FIG. 6 shows step S1 in FIG.
FIG. 5 is a flowchart showing details of Step 05, and its sequence will be described later.

FIG. 7 is a block diagram showing a plurality of exposure apparatuses installed in a factory. 701 to 703 are exposure apparatuses,
704 is a router, 705 is LAN wiring, and 706 is a computer that manages processes. The computer 706 stores and manages various information such as job parameters, device status, exposure results, and the like. Among them, there are AA measurement results of each sample shot in all alignment processes for all wafers. In this embodiment, information about which sample shot among the normal sample shot, the first substitute shot, and the second substitute shot is measured and used for calculating the correction value is stored.

Next, a procedure for transferring a new pattern onto a wafer W on which a pattern has already been formed will be described with reference to FIGS. When the sequence of FIG. 3 is started, first, in step S101, the reticle RT is loaded onto the reticle stage RS, and is held by suction. Next, in step S102, reticle set marks RSMR and RSML and reticle alignment mark RA
The alignment of the reticle RT with respect to the projection lens LN is performed using the MR and the RAML. That is, a set of the mark RAMR and the mark RSMR and the mark RAML
And a set of marks RSML are superimposed and imaged by the imaging device CM via the mark observation mirrors AMR and AML, respectively.
At this time, the control unit CU moves the reticle stage RS so as to align the two so that the amount of displacement between the two detected from the image output is within a predetermined allowable value.

At the time when the alignment is completed, the final result of the amount of displacement between the two within a predetermined allowable value is calculated as follows.
The difference between the X-axis direction of the reticle RT and the X-axis direction of the entire apparatus can be obtained, and the value is stored as a residual error θr. Further, from the same final result, the position of the center of the reticle RT can be obtained, and the value is stored as a vector R as follows. Here, R is obtained by multiplying the actual position of the center of the reticle by the reduction magnification of the projection lens LN, and further inverting the sign so as to represent the position of the inverted image.

[0032]

(Equation 1)

Next, in step S103, the wafer W is transferred to the wafer stage W by a transfer hand mechanism (not shown).
The wafer is sent onto the wafer stage S, and is suction-fixed on the wafer stage WS. In the next step S104, pre-alignment of the wafer W is performed with somewhat rough accuracy using the mark of the pattern already formed on the wafer W. That is, FIG.
As shown in the figure, the pre-alignment marks WAML and WAMR formed at two places on the wafer W are sequentially moved under the off-axis scope OS, respectively, and the position of the mark detected from the captured image and the XYθ at that time The position of each mark is measured from the position coordinates of the stage XYS, and the shift amount of the entire wafer is measured. The amount of wafer shift is calculated by using the matrix A as shown in the following equation.
The wafer shift amount is stored as a vector S.

[0034]

(Equation 2)

Here, βx and βy are X and Y of the wafer.
Where θx and θy are the X and Y of the wafer.
Sx and Sy represent shift amounts in the X and Y directions. These will be referenced in later steps. Here, since the value of θ is sufficiently small, sin
(Θ) ≒ θ, cos (θ) ≒ 1. Similar approximations are made in the following equations. However, since the measurement in this step is only measurement of two marks on the wafer, X and Y cannot be obtained independently for the shift amount in the rotation direction of the wafer. Therefore, the rotation error θ of the entire wafer is stored as the following equation. Keep it. θx = θy = θ

In this measurement, the magnification of the off-axis scope OS is switched to a low magnification, and the mark is detected in a wide field of view.

Next, in step S105, the shot arrangement on the wafer W and the chip rotation are measured for each sample shot. Each shot pattern formed on the wafer has alignment marks WML and WMR on the left and right of the shot as shown in FIG. Of these marks, the alignment marks of shots previously specified as sample shots are sequentially moved under the off-axis scope OS, and the positions of the alignment marks detected from the captured image and the XY at that time are determined.
The position of each alignment mark is measured from the position coordinates of the θ stage XYS, and the shift amount of the entire wafer is measured.

At this time, the off-axis scope OS
Is changed to a high magnification so that more precise measurement can be performed. Here, the sample shots specified in advance are, for example, SS1 to SS8, RS1-1 to RS1-1 in FIG.
This is a plurality of shots as indicated by RS8-1, RS1-2 to RS8-2. SS1 to SS8 are normal sample shots, and RS1-1 to RS8-1 are first alternative shots when there is a shot that cannot be measured among SS1 to SS8. RS1-2 to RS8-2 are second alternative shots when there is a shot that cannot be measured among the measured RS1-1 to RS8-1. For example, if the normal sample shot SS1 cannot be correctly measured, the first substitute shot SS1-1 is used instead for measurement. If this cannot be measured correctly, the second substitute shot SS1- instead of the normal sample shot SS1 is used.
2 is used for measurement.

The details of the processing in step S105 are shown in FIG.
The description of this portion will be made after the description of FIG.

The center position of each shot is (Dx, Dy),
Set the alignment mark position in the shot to (mx, my)
Then, the design position of the alignment mark on the wafer in each shot can be represented by the following vector.

[0041]

(Equation 3) The position of the off-axis scope OS is represented by the following vector.

[0042]

(Equation 4) Then, the target position for moving the XYθ stage XYS for measuring the alignment mark of each shot can be expressed as follows.

[0043]

(Equation 5)

When moving to the position of the vector P, the alignment mark of each shot can be seen at a position that can be measured by the off-axis scope OS. Therefore, the position of each alignment mark is obtained from the position of each alignment mark detected from the captured image and the position coordinates of the XYθ stage XYS at that time.

In step S106, it is checked whether or not the sample shots which have been correctly measured so far are two or more shots necessary for calculating the correction parameter. If two or more shots have been measured, the process proceeds to step S107. The process proceeds to step S108. Also, if the measurement has failed in step S105, the process proceeds to step S108.

In step S107, the values of the shift amounts βx, βy, θx, θy, Sx, and Sy of the entire wafer are newly obtained using the detected shift amounts of the respective alignment marks and the measured positions. This means that the matrix A and the vector S obtained in step S104 are obtained more precisely. As a result, in the next measurement, the alignment mark is seen almost at the center of the off-axis scope OS. Further, the i-th chip rotation amount θCi is obtained as follows from the difference between the measurement values and the distance between the left and right alignment marks of the i-th sample shot.

[0047]

(Equation 6) Further, the average chip rotation amount θC of the sample shots measured so far is obtained as follows.

[0048]

(Equation 7) Then, the wafer rotation portion is removed by the following equation, and θc is stored as the chip rotation amount. θc = θC−θx (3) Similarly, the chip magnification βCi is obtained by the following equation.

[0049]

(Equation 8) Further, the average chip magnification βC of the sample shots measured so far is calculated by the following equation.

[0050]

(Equation 9) Furthermore, the wafer magnification (β = (βx + βy) /
2) Remove the part and store βc as the chip magnification.

[0051]

(Equation 10)

Further, the position (mx, my) of the alignment mark in the chip is given by the following equation when the design position (measurement reference position) is (mx, mY), and the chip rotation and the chip magnification are taken into consideration.

[0053]

[Equation 11] The position of the alignment mark on the wafer in consideration of the chip rotation and the chip magnification is given by the following equation.

[0054]

(Equation 12)

The position of the alignment mark on the wafer (M
(x, My) is actually calculated in step S107 using the calculation formula (5) instead of the calculation formula (1). XYθ stage XY to measure alignment mark
Formula (5) is also used in formula (2) for calculating the target position for moving S.
Is used.

In step S107, an abnormal value may be rejected. This is a case where the residual shift amount is larger than a predetermined value. At this time, if the normal sample shot is measured, the fact that the normal sample shot of the sample shot of the layer of the wafer cannot be used is stored. If the first alternative shot has been measured, the fact that the first alternative shot cannot be used is stored. In both cases, it is determined that this sample shot has not been measured, and the process proceeds to step S108. If the second alternative shot has been measured, the fact that the second alternative shot cannot be used is stored. That is, the fact that the sample shot of this part cannot be used is stored. This information is stored in a computer 7 that manages the measured exposure apparatus and process.
06 or the like.

Next, in step S108, it is determined whether or not the measured shot is the last sample shot.
If it is not the last, the process returns to step S105. If it is the last shot, the process proceeds to step S109. In this case, the shift amounts βx, β of the entire wafer calculated in step S107
y, θx, θy, Sx, Sy, chip magnification βc, and chip rotation amount θc are values calculated from measured values of all sample shots, and are correction parameters used in steps S109 and S110.

In step S109, the XYθ stage X
YS is rotated in the θ direction by the next θw, and the direction of the shot array is adjusted to the direction of the reticle RT. θw = θr−θx

In this case, the wafer placed as shown in FIG. 5A rotates as shown in FIG. 5B, and it is assumed that the pattern already formed on the wafer W has no chip rotation. If possible, reticle projection image RTI
And the direction of the shot is exactly the same.

Alternatively, the XYθ stage XYS is
By rotating by w, the average direction of each shot may be adjusted to the direction of the reticle. θw = θr− (θx + θc)

In this case, the wafer W rotates as shown in FIG. 5C, and even if the pattern formed on the wafer has a chip rotation, the reticle projection image RTI and the shot direction are accurate. Will match.

Next, in steps S110 to S112, the circuit pattern on the reticle RT is exposed and transferred onto the wafer W by the step-and-repeat method. That is, in step S110, the position coordinate Di on the wafer of the i-th shot in the following equation is obtained from the information of the shot arrangement determined in advance by the console CS.

[0063]

(Equation 13)

From the matrix A and the value of the vector S measured and corrected in steps S107 and S109, the movement target vector Ei of the XYθ stage XYS is calculated as follows.
Ask for:

[0065]

[Equation 14]

Then, the XYθ stage XYS is placed at that position.
To move. In other words, the XYθ stage XYS is step-and-repeat such that the position in the XY direction is a position obtained by correcting the designed shot array based on the rotation error of the shot array on the wafer W in the θ direction (around the Z axis). You will move in a way. Next, step S111
, The exposure shutter SHT is opened and closed to open the reticle RT
The upper pattern is exposed and transferred onto the wafer W via the projection lens LN. Steps S110 to S112 are repeated until it is determined in step S112 that the exposure of the last shot on the wafer has been completed.

After the exposure of the last shot is completed, in step S113, the wafer W on which the exposure transfer has been completed is carried out of the wafer stage WS by the carrying-out hand mechanism (not shown), and all the wafers to be processed in the determination of S114 are processed. Step S1 until it is determined that the exposure transfer has been completed.
03 to S114 are repeated.

If it is determined in step S114 that there are still wafers to be processed, step S1 is performed for each wafer or every several wafers for confirmation.
02, the positional change of the reticle RT may be confirmed and corrected.

As described above, a new pattern can be transferred onto a wafer on which a pattern has already been formed, without chip rotation.

Next, the details of step S105 will be described with reference to FIG. First, in step S201, information is obtained as to whether or not measurement has been correctly performed when an alignment was previously performed using the same sample shot of the same layer of the wafer currently being processed. When aligning for the first time, all the sample shots are stored so that they can be used. This information may be stored in the exposure apparatus itself, or may be stored in the computer 706 that manages the process.

Next, in step S202, it is checked whether or not a normal sample shot has been stored so as to be used for AA measurement. If it is stored that it can be used, the process proceeds to step S205.
Go to 203.

In step S203, it is checked whether or not the first substitute shot is stored so as to be used for AA measurement. If it can be used, the process proceeds to step S206. If not, the process proceeds to step S204.

In step S204, it is checked whether or not it is stored that the second alternative shot can be used for AA measurement. If it can be used, the process proceeds to step S207. If it cannot be used, the measurement of this sample shot ends. Then, the process proceeds to step S106. In step S106, since there is no new effective measurement, the process proceeds to step S108.

In step S205, a setting is made so that a normal sample shot is used for AA measurement.
Proceed to 8. In step S206, the first substitute shot is set to A
It is set to be used for A measurement, and the process proceeds to step S208.
In step S207, the second substitute shot is set to be used for AA measurement, and the process proceeds to step S208.

In step S208, A in the previous step
AA measurement is performed by moving the alignment mark of the shot set to be used for A measurement to the microscope position. There are cases where the measurement can be performed correctly, cases where the position cannot be measured at all, and cases where the amount of deviation from the target value is larger than a predetermined value, and the like, which prevent correct measurement. When the measurement is over,
Proceed to step S209.

In step S209, it is checked whether the measurement has been correctly performed. Step S if correct measurement
The process proceeds to 212, and if the measurement has failed, the process proceeds to step S210. In step S212, the fact that the measured sample shot can be used is stored. This information may be stored in the exposure apparatus itself, or may be stored in the computer 706 that manages the process. When the processing is completed, the process proceeds to step S106.

In step S210, it is checked whether or not the measurement has been performed in the second alternative shot. If the measurement has been performed with the second alternative shot, the process proceeds to step S213. If the measurement has not been performed with the second alternative shot, the process proceeds to step S211. In step S213, it is stored that the sample shot cannot be used because the measurement could not be correctly performed in the second alternative shot. That is, the normal sample shot, the first
It stores that the substitute shot and the second substitute shot cannot be used. This information may be stored in the exposure apparatus itself, or may be stored in the computer 706 that manages the process. When the information is stored in the computer 706 that manages the process, a device that stores this information, for example, the device 701, and a device that reads and uses the stored information, for example, the device 7
02 and the device 703 may be different. Then, the process proceeds to step S106. In step S106,
Since there is no new valid measurement shot, step S108
Proceed to.

In step S211, it is checked whether or not the measurement has been performed in the first substitute shot. If the measurement has been performed on the first alternative shot, the process proceeds to step S214. If the measurement has not been performed on the first alternative shot, the process proceeds to step S215. In step S214, since measurement could not be performed correctly with the first substitute shot, the second substitute shot is set to be used for measurement, and the process is repeated again from step S208.

In step S215, since the measurement could not be correctly performed by the normal sample shot, the first
Set to use the alternative shot, and repeat Step S
Repeat from 208.

According to the present embodiment, when AA measurement is performed on a certain layer of a certain wafer, a normal sample shot cannot be measured correctly, so that measurement is performed using a substitute shot, or the substitute shot cannot be measured correctly. Sometimes, in another step, when aligning again using the same layer of alignment marks on the same wafer, the first alternative shot,
Alternatively, since the process directly shifts to the measurement of the second alternative shot, or skips them and shifts directly to the next sample shot, alignment can be performed quickly without spending extra stage movement time and AA measurement time.

In this embodiment, the alternative shot is selected. However, if there is no alternative shot, if the measurement cannot be performed correctly, the next shot is skipped from the next time and the process proceeds to the measurement of the next shot. I just need. In this embodiment, the information obtained by AA measurement on the same layer of the same wafer is used. However, even if the layers are different, shots that cannot be AA-measured may not be used for AA measurement from the next time. In addition, the sample shots in which the measurement order is skipped need not be included in the measurement order, and the measurement order may be set later. Furthermore, since the wafer condition is often the same for each lot, if the AA measurement cannot be performed correctly at the beginning of the lot and the measurement is performed using the substitute shot, the next wafer in the lot will be replaced with the first wafer. It is also possible to use the same substitute shot that was correctly measured for the AA measurement.

<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.). Step 1
In (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,
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 processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). including. In step 6 (inspection), inspections such as an operation check 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 to align the circuit pattern of the mask on a plurality of shot areas of the wafer and perform printing exposure. Step 17
In (development), the exposed wafer is developed. Step 18
In (etching), portions other than the developed resist image are scraped off. 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 manufacturing method of this embodiment, it is possible to efficiently manufacture a large-sized device which has conventionally been difficult to manufacture.

[0085]

As described above, even when there is a sample shot whose measurement result cannot be used because measurement cannot be performed due to a mark defect or the like or a correct position cannot be measured, measurement of such a sample shot is expensive. Eliminate unnecessary stage movement time and measurement time
Positioning can be performed quickly. Therefore, device manufacturing can be performed efficiently.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a semiconductor exposure apparatus according to one embodiment of the present invention.

FIG. 2 is a plan view showing an XYθ stage of the apparatus of FIG.

FIG. 3 is a flowchart showing a sequence in the apparatus of FIG. 1;

FIG. 4 is an explanatory view of an alignment mark and a sample shot on a wafer in the apparatus of FIG. 1;

FIG. 5 is a diagram showing how the position of a wafer is corrected after alignment in the apparatus of FIG. 1;

FIG. 6 is a flowchart showing details of step S105 in FIG. 3;

FIG. 7 is a block diagram showing a state where a plurality of exposure apparatuses are installed in a factory.

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]

701 to 703: exposure apparatus, 704: router, 705:
LAN wiring, 706: Computer for managing parameter files, AMR, AML: Mark observation mirror, C
M: imaging device, CS: console, CU: control unit, IFX, IFY, IFθ: laser interferometer, IL: exposure light source, LN: projection lens, MRX, MRY: mirror to which XYθ stage is fixed, MX, MY , Mθ: motor, OS: off-axis scope, PHC: photochromic plate, PT: pattern on reticle, RA
MR, RAML: reticle alignment mark, RM
R, RML: reticle mark, RT: reticle, RS:
Reticle stage, RS1-1 to RS8-1: first substitute shot, RS1-2 to RS8-2: second replacement shot, RSMR, RSML: reticle set mark, SH
L, SHR: mark exposure shutter, SHT: exposure shutter, SS1 to SS8: normal sample shot, W: wafer, WAML, WAMR: pre-alignment mark,
WML, WMR: alignment mark, WS: wafer stage, XYS: XYθ stage.

Claims (10)

[Claims] 1. An alignment method for measuring the position of an alignment mark for each sample shot selected in advance from among shots on a substrate and performing alignment of the substrate based on a result of the measurement, the method comprising: A positioning method for determining whether or not the sample shot is suitable for position measurement based on a result of the position measurement performed previously on the sample shot before performing the position measurement. 2. The alignment method according to claim 1, wherein a result of the position measurement as a basis for the determination is performed on the same substrate as a substrate to be currently aligned. 3. The alignment according to claim 1, wherein the result of the position measurement serving as a basis for the determination is performed on a substrate of the same type as a substrate to be currently aligned. Method. 4. The method according to claim 1, wherein the result of the position measurement as a basis of the determination is performed for the first substrate of the same lot as the substrate to be currently aligned. The alignment method described. 5. The method according to claim 1, wherein the position measurement result serving as the basis of the determination is obtained for a substrate in the same process as the substrate to be currently aligned. Or the alignment method according to item 1. 6. The method according to claim 1, wherein, if it is determined that the position is not suitable for position measurement as a result of the determination, position measurement is performed for an alternative sample shot instead of the sample shot. The alignment method according to any one of the preceding claims. 7. The alignment method according to claim 1, wherein after performing position measurement for each sample shot, the result is stored for subsequent determination. . 8. A method for aligning a substrate with respect to an original plate according to any one of claims 1 to 7, and thereafter exposing a pattern of the original plate to each shot position of the substrate sequentially. A device manufacturing method. 9. An alignment apparatus comprising: means for aligning a substrate by the method according to claim 1. Description: 10. A means for aligning a substrate with respect to an original plate by the method according to any one of claims 1 to 7, and exposing the pattern of the original plate sequentially to each shot position of the substrate aligned by the method. An exposure apparatus comprising: an exposure unit that performs exposure.