JPH01187817A - Aligning method - Google Patents

Abstract

PURPOSE:To control exposure conditions, such as focal point position, exposure amount, etc., of a projection lens, to set optimum exposure conditions of a stepper or the like accurately in a short time, and to shorten the setup time of the stepper by detecting the predetermined pattern length of a resist pattern in which the width of its line is varied continuously or stepwisely, and calculating optimum forming conditions by a main control system on the basis of the detection result. CONSTITUTION:A pattern made of a linear pattern in which the width of a line formed on a reticle R is continuously or stepwisely varied is sequentially varied by driving at least one of the focal point position and the exposure amount of a projection lens 6 through the lens 6 by a shutter 3, a Z stepper 7, and transferred onto a wafer W. The predetermined pattern length Ly or diameter R of a resist pattern RP formed on the wafer W is detected by an alignment optical system of a stepper SR. A main control system 50 for generally controlling the operation of a whole stepper SR including the alignment optical system calculates the optimum forming conditions of the pattern RP on the basis of the pattern length Ly or diameter R, and controls the exposure conditions, such as the focal point position, exposure amount of the lens 6 in response to the optimum forming conditions.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is applicable to the manufacturing process of semiconductor devices, particularly in the process of forming a circuit pattern of a device on a photosensitive substrate such as a semiconductor wafer. The present invention relates to an exposure method for printing a mask pattern on a photosensitive substrate in a step-and-repeat manner under exposure conditions.

[Conventional technology]

Conventionally, the manufacturing process of semiconductor integrated circuits such as VLSI, etc.
In this lithography process, a step-and-repeat projection exposure device (wafer stepper, hereinafter simply referred to as a stepper) is mainly used to expose semiconductor elements formed on a mask or reticle (hereinafter referred to as a reticle). A circuit pattern is sequentially transferred onto a photoresist substrate (hereinafter referred to as a wafer) through a projection lens to form a circuit pattern of a semiconductor element on the wafer. At this time, if the focus position of the projection lens is not adjusted accurately, the projected image of the circuit pattern on the reticle will not be accurately formed on the wafer, and a blurred pattern will be formed on the wafer, resulting in so-called poor resolution.
1R happens. As described above, unless the exposure conditions of the stepper, including the focal position of the projection lens, are set accurately at the time of starting the apparatus, it will not be possible to obtain a semiconductor element that satisfies the desired characteristics.

Therefore, for example, a reticle on which a plurality of rectangular patterns with different line widths are formed, including a pattern smaller than the minimum line width of a circuit pattern, is used as a reticle. The line width of the resist pattern formed on the developed wafer is transferred onto the wafer by sequentially changing the exposure conditions (focal position of the projection lens, exposure amount) every 17 steps. 3 by electron microscope
Detection is performed using a 2M length measurement method, an image processing method using a television camera (ITV), a method of irradiating a resist pattern with spot light and detecting the scattered light, or the like.

The optimum formation conditions for the resist pattern are determined from this line width, and each exposure condition of the stepper, such as the focal position of the projection lens and the exposure amount, is set according to the optimum formation conditions. With the exposure conditions set in this way, the stepper starts processing and sequentially transfers the circuit pattern formed on the semiconductor device reticle onto the wafer under the optimum exposure conditions.

[Problem to be solved by the invention]

However, when a scanning electron W4 microscope is used in this type of exposure method, the scanning electron microscope itself is expensive, and evacuation etc. are required when mounting the wafer, making it difficult to measure the line width of resist patterns. The problem was that it took time. In the line width detection method using ITV or spot light, when the line width of the circuit pattern to be transferred becomes sub-micron, it becomes difficult to detect the line width, and the resist pattern changes due to changes in exposure conditions. There was also the problem that the measurement error was large due to the small change in line width, and it was not possible to accurately set the optimum exposure conditions. Furthermore, due to the above-mentioned decrease in measurement accuracy, etc., there is a problem in that it takes time to process the detected line width, resulting in a decrease in throughput.

The present invention has been made in consideration of the above points, and prevents a decrease in the measurement accuracy of resist patterns, sets the optimum exposure conditions of a stepper, etc. with high precision and in a short time, and improves the set-up time of the stepper. The purpose of this study is to provide an exposure method that can reduce the time required to transfer a mask pattern onto a wafer.

[Means to solve problems]

In order to solve this problem, in the present invention, patterns CPSCPa and CP formed on the reticle R are formed of linear patterns whose line widths change continuously or stepwise.
b, CPc or pattern SS is transferred onto the wafer W through the projection lens 6 by sequentially changing the focus position of the projection lens 6 and the exposure amount (one of which is changed by driving the shutter 3.2 stage 7). Then, Unino\W
A predetermined pattern length Ly (and Lx) or diameter R of the resist pattern RP formed on the stepper SR
It is configured to detect using an alignment optical system equipped with. Further, the main control system 50, which centrally controls the operation of the entire stepper SR including the alignment optical system, calculates the optimal forming conditions for the resist pattern RP based on the pattern length Ly (and Lx) or the diameter R, and calculates the optimal forming conditions for the resist pattern RP. It is configured to control exposure conditions such as the focal position of the projection lens 6 and the amount of exposure depending on the formation conditions.

[Effect]

According to the present invention, a predetermined pattern length of a resist pattern whose line width changes continuously or stepwise is detected using an alignment optical system of a stepper or an inspection device such as an ITV, and based on the detection result. The main control system calculates the optimal forming conditions. Further, the exposure conditions such as the focal position of the projection lens and the amount of exposure are controlled according to the optimum formation conditions.

As a result, the alignment optical system of the stepper or the IT
Using V, etc., it is possible to automatically measure the predetermined pattern length of the resist pattern without reducing measurement accuracy, etc., and the optimum exposure conditions are accurately set, and the setup time of step 7 is shortened. , semiconductor devices can be obtained with high productivity.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings. 1st
The figure is a plan view showing a schematic configuration of a stepper SR suitable for applying the method according to the first embodiment of the present invention. FIG. 2 is a block diagram of the control system of this stepper SH. Here, the configuration of the stepper SR will be briefly described since it is disclosed in, for example, Japanese Unexamined Patent Publication No. 130742/1983, which was previously filed by the applicant of the present invention.

In FIGS. 1 and 2, an illumination light source 1 generates illumination light with a wavelength <n light wavelength that will sensitize the resist, and this illumination light passes through a first condenser lens 2 and then through a shutter 3. and reaches the second condenser lens 5. Shack-3 is the shutter drive unit (hereinafter referred to as 5-ACT)
4, the second condenser lens 5 is driven to control the transmission and blocking of illumination light, and the second condenser lens 5 illuminates the reticle R with uniform illumination light. A reduction projection lens (hereinafter simply referred to as a projection lens) 6 with a double-sided or one-sided telescend link is:
175 or 1 image of the pattern drawn on reticle R
/10, and the reduced image is projected onto the wafer W coated with resist.

Here, the projection lens 6 used in this example is the reticle R
The optical system has a non-telecenter link on the side and a telecenter link on the wafer W side. The wafer W is vacuum-adsorbed to the wafer holder (θ table) 110, and the drive unit (θ-ACT) 1
11, it is slightly rotated. This wafer holder 11
0 is provided on an X-Y stage 9 that moves two-dimensionally and a Z stage 7 that moves up and down (in the optical axis direction of the projection lens 6). Below, X-Y stage 9, Z stage 7
and wafer holder (θ table) 110 are collectively referred to as wafer stage WS. Wafer stage WS is moved in the X and Y directions by a drive unit (X-ACT) 108 and a drive unit (Y-ACT) 109, respectively, and furthermore, the wafer stage WS is moved in the X and Y directions by a drive unit (X-ACT) 108 and a drive unit (Y-ACT) 109. The values are detected by laser interferometers 106, 107, respectively. Further, the wafer W is configured to be movable in the optical axis direction of the projection lens 6 by a drive unit (Z-ACT) 8 that moves the Z stage 7 up and down. Z-ACT 8 and a focus detection bag N(
(hereinafter referred to as AFD) 105 constitutes automatic focus adjustment means.

Now, the stepper SR has three alignment optical systems for aligning the reticle R and the wafer W. One is TTR (Through the
reticle) type Gui-Pai-Gui alignment system (
(hereinafter referred to as the DDA system), and the DDA system 10.11.
12, the mark on the reticle R and the alignment mark on the wafer W are superimposed through the mirrors 10a, lla, 12a and the projection lens 6, and are observed simultaneously. Next, mark images of both the mark on the reticle R and the alignment mark on the wafer W are photoelectrically detected, and the DDA system 10
, 11 detect the positional deviation in the Y direction, and the DDA system 12 detects the positional deviation in the X direction.

Also, use the reticle R as a reticle stage (not shown)! ! When placing the reticle, reticle alignment is performed by the DDA system. The other is the 'I'TL (through-the-lens) type laser step alignment system (hereinafter referred to as
(called the LSA system), and the LSA system 20 is a mirror 2oa
, 20b and the projection lens 6, a spot light (sheet beam) SP is irradiated onto an alignment mark (especially a diffraction grating mark) formed on the wafer W, and diffracted light (or scattered light) from the mark is received. and photoelectric detection. Based on this photoelectric signal and the position signal of wafer stage WS from laser interferometer 107, the position of the alignment mark on wafer W in the Y direction is detected. Furthermore, LS-A
The system 20 is for detecting only the position of the wafer W in the Y direction, and is actually an LSA for detecting the position in the X direction.
The systems are arranged similarly. In FIG. 1, only the mirror 21a of the LSA system 21 for X-direction detection corresponding to the mirror 20a for Y-direction detection is shown. The other is an off-axis type wafer alignment system, and the wafer alignment systems 30 and 31 use vibrating mirrors such as galvanometer mirrors (not shown) to direct an elliptical spot light elongated in the X direction onto the wafer W. The wafer W is vibrated minutely in the X direction, and a mark formed elongated in the X direction is irradiated onto the wafer W. The diffracted light (or scattered light) from this mark is received to detect charging, and the mark on W and the wafer alignment system 30
．． The displacement in the X direction with respect to the 31 spotlights is detected respectively.

Here, as a wafer alignment system, in addition to the above-mentioned method of irradiating the alignment mark on the wafer W with a spot light, for example, the method disclosed in Japanese Unexamined Patent Publication No. 62-11101, which was previously filed by the applicant of the present application, is
As disclosed in Japanese Patent No. 278402, there is also a method in which an alignment mark on a wafer W is observed under magnification and an image signal from an image sensor such as an ITV is processed.

The main control system 50 shown in FIG. 1 includes a processor (hereinafter referred to as CPU) 100 such as a microcomputer or minicomputer, an interface circuit (hereinafter referred to as IFC) 101, etc., as shown in FIG. Via these, the operation of the entire apparatus including the three alignment systems mentioned above is controlled in an integrated manner. The Gui-Pai-Gui alignment processing circuit (hereinafter referred to as DDAC) 102 is a DDA
Co-operating with system 10.11, marks on reticle R and wafer W
The DDA system 12 detects the relative positional deviation amount in the X direction with respect to the upper alignment mark, and similarly, the DDA system 12 detects the relative positional deviation amount in the X direction. laser·
A step alignment system processing circuit (hereinafter referred to as LSAC) 103 uses the LSA system 20.21 to spot light (
(Sheet beam) The position in the X direction and the X direction with respect to SP are detected respectively. A wafer alignment system processing circuit (hereinafter referred to as WAD) 104 detects the positions of the seven alignment marks on the wafer W in the X direction with respect to the spot light using the wafer alignment systems 30 and 31, respectively. The CPU 100 adjusts the
TIO6, Y-ACTI O7, Z-ACT8, θ-A
Predetermined drive commands are output to CT111 and 5-ACT4, respectively.

Next, the operation of this embodiment will be explained using FIGS. 3 and 4. FIG. 3 is a plan view showing a schematic configuration of a pattern used in setting the exposure conditions of the stepper SH in this embodiment. FIG. 4 is a diagram for explaining the operation of setting exposure conditions. In this embodiment, as shown in FIG. It is assumed that a reticle R is used in which a pattern (hereinafter referred to as pattern CP) in which three lines are formed at regular intervals is formed.

Therefore, Stepper SR first uses 5-ACT4 and Z
- Transfer the pattern CP onto the wafer W in a step-and-repeat manner while changing at least one of the focal position of the projection lens 6 and the exposure amount by driving the shutter 3 and the stage 7 via the ACT8. For example, the exposure is performed by changing the focal position of the projection lens 6 while keeping the exposure amount at a constant value, and then the exposure is performed by changing the focal position while maintaining the exposure amount at a slightly changed value. Step pattern CP on top
Transfer in a matrix using an and-repeat method. Here, if the pattern CP is transferred onto the wafer W by changing at least one of the focus position and the exposure amount as described above,
The ratio of the bright part to the dark part of the pattern CP, the so-called duty ratio, changes depending on the focal position and the exposure amount. pattern CP
Since the wedge-shaped patterns CP are arranged in parallel, the pattern has a constant pitch but a variable duty ratio. Therefore, the DAT ratio is the resist pattern R
P pattern length (length in the direction perpendicular to the pitch direction)
It will be converted to Ly. Therefore, the relationship between the exposure conditions such as the focus position of the projection lens 6 and the exposure amount when transferred under various exposure conditions in advance, and the line width of each specific pattern transferred under each exposure condition and the pattern length of the resist pattern RP. (hereinafter referred to as initial conditions) can be stored, and optimal exposure conditions can be determined based on these initial conditions and the measured pattern length L7.

Therefore, next, the resist pattern RP formed on the wafer W is detected using the alignment optical system provided in the stepper SR. Here, as shown in FIG. 4, in this embodiment, the pattern length Ly of the resist pattern RP is
Since the spot light SP is arranged to be suitable for measurement using the LSA system 20, the spot light SP extends in the X direction, and the pattern CP is arranged so that the arrangement direction (pitch direction) of the resist pattern RP coincides with the is transferred onto the wafer W. Incidentally, using LSA system 20.21, resist patterns RP such as patterns CP and CPa are scanned with spot lights SPy and SPx in a direction substantially perpendicular to the pattern arrangement direction, and diffracted light (or scattered light) from the resist patterns RP is detected. In order to receive light, the waveform of the photoelectric signal of each resist pattern RP has a specific periodic structure.

Now, in LSACI O3, the Y-A
The wafer stage WS is moved in the X direction via the CTI O9 (FIG. 4(a)). At this time, Fig. 4(b), (
As shown in C), when the spotlight SP starts scanning the edge E of the resist pattern RP at the position y1, the edge E,
Scattered light is generated, and a photoelectric detector (not shown) starts outputting a photoelectric signal S corresponding to the amount of this scattered light. Furthermore, as the spot light SP scans the resist pattern RP, both the line width and the height of the resist pattern RP increase, and accordingly, the scattered light also increases. Then, the center of the laser beam forming the Suboft light SP is at the position ayz and the edge E.
2, the output signal S from the photodetector decays rapidly.

Therefore, the LSAC 103 is located at the position y where the photoelectric signal S is generated.
, and the Y coordinate value Y + of the position y2 where the output signal S attenuates.
, Yz are detected by a laser interferometer 107. Based on this Y coordinate value Y+-Yt, the LSAC 103 calculates the pattern length Ly of the resist pattern RP, and stores the pattern lengths T and y. Next, the LSAC 103 processes each resist pattern RP formed on the wafer W by changing at least one of the focal position of the projection lens 6 and the exposure amount.
The pattern lengths t and y of are sequentially measured in the same manner as described above, and each pattern length t and y is memorized.

Next, CPU i o o determines the optimal focal position and exposure amount of the projection lens 6 based on the detection result of the LSAC 103, that is, the stored length Ly of each pattern. That is, as described above, the CPU 10 changes at least one of the first @ order focal position and the exposure amount, and based on the pattern lengths t and y of the resist pattern RP formed on the wafer W.
0 first detects the focal position where the pattern length Ll is the longest among the resist patterns RP formed by changing only the focal position with the same exposure amount. That is, the CPU 100 detects the focal point position at which the pattern length Ly is closest to the pattern length of the pattern CP formed on the reticle R. Then, CI''Uloo stores this focal position as the optimum focal position of the projection lens 6.

Next, at this optimum focus position, only the exposure amount is changed and the wafer W is
Pattern length t of the resist pattern RP formed above
, y and the initial conditions, the CPU 100 detects the optimum exposure amount. That is, a pattern length Ly that matches or substantially matches the pattern length when transferred with the optimum exposure amount is detected, and the CPU 100 stores the exposure amount when this pattern is transferred as the optimum exposure amount.

According to the optimal focus position and exposure amount determined as above, the CPU 100 drives and controls the shutter 3 and the Z stage 7 via 5-ACT4 and Z-ACT8, respectively. Therefore, the reticle R for semiconductor devices is always transferred onto the wafer W under optimal exposure conditions, and a resist pattern is formed on the wafer W with a desired line width.

In addition, a pattern CPa in which wedge-shaped patterns shown in FIG. 5(a) are arranged with a certain pinch in mutually orthogonal directions (X and , the focal position is changed for each shot while the exposure amount is kept constant, and the image is transferred onto one frame W.

However, the exposure dose does not need to be the optimum exposure dose, and may be any exposure dose that forms a resist pattern.
LSACIO3 calculates each pattern length Ly, Lx of the resist pattern RP arranged in the direction and the
A system 20.21 spot light spy.

Detection is performed using SPx in the same manner as described above (Fig. 5(b)
)). Then, based on the pattern length LX%L)l measured by the LSAC 103 and the initial conditions, the CPU 1
00 calculates the focus position at each position within the exposure field. By detecting the focal position within the exposure field in this manner, it is possible to determine the field tilt, field curvature, astigmatism, etc. at each position based on the focal position.

Furthermore, a reticle R on which a pattern CP shown in FIG. 3 is provided on the entire surface is transferred onto a wafer W under arbitrary same exposure conditions (same focal position, same exposure amount). The LSAC 103 detects the pattern length Ly of each resist pattern RP within the exposure field using the LSA system 20 in the same manner as described above.

Based on this pattern length Ly and initial conditions, the CPU
100 can determine the non-uniformity of line width within the exposure field due to uneven illumination or the like.

Further, the reticle R on which the pattern CP shown in FIG. 3 is formed is transferred onto the wafer W by a step-and-repeat method under the same predetermined exposure conditions. Next, as above, LS
AC103 is the pattern length Ly of resist pattern RP
is detected, and based on this measurement value and initial conditions, the CPU
too can determine the non-uniformity of the line width of the resist pattern RP due to uneven development or the like. Here, uneven lighting,
The exposure conditions for detecting non-uniformity in line width due to uneven development etc. do not need to be optimal exposure conditions as in the case of detecting image plane tilt etc., and may be any exposure conditions that form a resist pattern.

Thus, according to this embodiment, instead of detecting the line width of the resist pattern RP, a predetermined pattern length is detected, and the exposure conditions are determined based on this detection result. Therefore, a decrease in measurement accuracy, etc. is prevented, and since automatic measurement can be performed, the centamp time of the stepper SR is shortened, and a decrease in throughput is also prevented. Further, since it is possible to detect non-uniformity in the line width of the resist pattern RP due to uneven development, etc., it is also possible to detect the operating state of the resist processing device (coater/developer).

In this example, a wedge-shaped pattern was used as the pattern in which the line width changed continuously or stepwise, and this wedge-shaped pattern was transferred onto the wafer W in an arrangement (pattern CP) as shown in FIG. However, the pattern used in this embodiment is not limited to the above-described wedge pattern and its arrangement. For example, as shown in FIGS. 6(a) and (b), a pattern CPb in which two patterns CP are symmetrically combined (in the beam scanning direction), or a continuous pattern including a pattern CPc in which the line width changes stepwise, etc. Any pattern may be used as long as it has one or more linear patterns whose line widths change in a fixed or stepwise manner, regardless of the pitch or arrangement. Furthermore, it is clear that the same effect can be obtained by using a pattern as shown in FIG. 7(a), the so-called Siemens star pattern (hereinafter referred to as pattern SS), instead of patterns CP, 'CPa, etc. . However, in this pattern SS, the line width is very narrow near the center of the pattern, making it difficult to manufacture, and it is less effective in detecting line widths exceeding the resolution limit of the projection lens. There is no need to form a pattern in a portion where the line width is less than the limit value. In Figure 7(a), 45
It shows a divided pattern SS. The exposure method using this pattern SS will be described below.

First, like the wedge-shaped pattern described above, the pattern is transferred onto the wafer W in a step-and-repeat manner while changing at least one of the focal position of the projection lens 6 and the exposure amount. L.S.
The AC 103 uses the spot light SPy of the LSA system 20 to scan the resist pattern RP in the Y direction. From the photoelectric signal S' (Fig. 7(C)) obtained as a result, CPtJlo
o is the resist pattern RPO formed with the same -i light intensity
Among them, the focal position where the unresolved portion at the center is the smallest, that is, the diameter R of the center detected by the spot light SPy is the smallest, is defined as the optimal focal position.

Next, the resist pattern RP formed at the optimal focus position
In O, the exposure amount for the diameter R that matches or almost fails the initial condition is defined as the optimum exposure amount. Also, like the wedge-shaped pattern, a resist pattern is formed on the wafer W by changing the focal position with the same exposure amount.

Turn RP, respectively LSA system 20.21 spot light S
By detecting using PY' and SPx, the image plane tilt, etc. can be determined. Similarly, non-uniformity in the line width of the resist pattern RP due to uneven illumination, uneven development, etc. can be detected.

Further, in this embodiment, the optimum focal position and exposure amount were determined after measuring all the pattern lengths of each resist pattern RP formed in a matrix on the wafer W. However, without measuring the pattern lengths of all resist patterns RP in advance, the optimum focus position can be determined by first measuring the pattern lengths of resist patterns RP formed with the same exposure amount and changing only the focus position. The optimum exposure amount may be determined by measuring the pattern length of only the resist pattern RP formed by changing the exposure amount at this optimum focus position. Furthermore, although the pattern length of the resist pattern RP was detected using the LSA system 2o121 as an alignment optical system included in the stepper SR, the pattern detection system used in this embodiment is limited to the LSA system 20.21. Inspection equipment that measures line width using circular spot light, alignment optical systems other than LSA systems (DD
A system 10.11.12, wafer alignment system 30.
31) etc. may also be used. For example, when using the DDΔ system, the resist pattern RP formed on the wafer W is observed under magnification for both the pattern CP (or CPa) and the pattern SS, and one-dimensional or two-dimensional images are obtained using an image sensor such as an ITV. It is clear that the same effect can be obtained by performing processing and detecting the pattern length or diameter R of the resist pattern RP based on this image signal.

Furthermore, in this embodiment, when detecting the non-uniformity of the line width due to the image plane (orientation, uneven illumination, etc.), the pattern is newly set on the wafer W, in addition to setting the optimum focus position and exposure amount. However, without performing exposure again, for example, a reticle R on which pattern CPa or pattern SS is formed at the center and a plurality of positions on its outer periphery can be transferred to at least one of the focus position and the exposure amount in the same manner as described above. If the images are transferred sequentially to each of the center of the wafer W and a plurality of positions on the outer periphery of the wafer W in a matrix pattern, the optimal exposure conditions (focal position, exposure f), image plane inclination, and Point aberration etc. can be detected.

〔Effect of the invention〕

As described above, according to the present invention, by detecting the predetermined pattern length or diameter of the resist pattern, it is possible to set the optimum exposure conditions, and also to detect the image plane tilt, etc., and the operating state of the coater/developer. Therefore, the optimum exposure conditions can be set using the inspection equipment or the stepper's alignment optical system, etc. This also prevents deterioration in measurement accuracy, etc., and the optimum exposure conditions can be automatically set. This has the advantage that the time is shortened and a decrease in throughput can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a schematic configuration of a stepper suitable for applying a method according to an embodiment of the present invention, FIG. 2 is a block diagram of a control system of the stepper, and FIG. 3 is an embodiment of the present invention. FIG. 4(a) is a schematic plan view of a pattern used in setting the optimum exposure conditions of the stepper in the example, and FIG. 4(b) is a schematic diagram showing a state in which a spot light scans a resist pattern. A cross-sectional view of the resist pattern in the scanning direction by the spot light, FIG. 4(c) is a diagram showing the waveform of a photoelectric signal when the spot light scans the resist pattern, and FIG. 5(a) is an embodiment of the present invention. FIG. 5(b) is a plan view of a pattern used to detect the image plane inclination within the exposure field, FIG. 5(b) is a schematic diagram showing a state in which a spot light scans a resist pattern, FIG. 6(a) 7(b) is a schematic plan view of patterns CPb, CPc, which can be used in the same manner as pattern CP etc. in an embodiment of the present invention, and FIG. 7(a) is a pattern used in an embodiment of the present invention. a schematic plan view of a pattern SS that can be similar to CP and pattern CPa;
FIG. 7(b) is a schematic diagram showing the state in which the spot light scans the Siemens star resist pattern, and FIG. 7(C)
is a diagram showing the waveform of a photoelectric signal when a spot light scans a resist pattern. 3... Shutter, 4... Shutter drive unit, 6...
...Projection lens, 7...Z stage, 8...Z stage drive unit, 10.11.12...Gui-Pai-Gui alignment system, 20.21...Laser step alignment system , 30.31... Wafer alignment system, 50... Main control system, 106.107... Laser interferometer, W... Wafer, R... Reticle.

Claims (2)

[Claims] (1) In an exposure method of an apparatus that projects and exposes a pattern formed on a mask onto a photosensitive substrate via a projection optical system,
a first step of transferring the mask having a linear pattern whose line width changes continuously or stepwise onto the photosensitive substrate via the projection optical system; a predetermined resist pattern formed on the photosensitive substrate; a second step of detecting the pattern length of the resist pattern using a pattern detection system; a control means calculates optimal forming conditions for the resist pattern based on the pattern length detected in the second step; and a third step of controlling the exposure processing conditions according to the exposure method. (2) Claim (1) characterized in that the exposure apparatus has an alignment system as the pattern detection system, and the alignment system operates to detect a predetermined pattern length of the resist pattern. Exposure method described