JPH11251236A - Exposure method and exposure apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve throughput and exposure accuracy. SOLUTION: The temperature of the wafer being transferred is measured by a substrate transfer device for transferring the wafer and holding it by a wafer holder by suction (ST1), and the temperature of the holder is measured (ST2).
After the temperature difference between the measured temperature of the holder and the temperature of the wafer falls within a preset allowable range (ST3, 4), the wafer is sucked and held by the holder (ST5), and exposure processing is performed (ST5). ST6). There is no need to uniformly wait for a time when the temperature of the wafer is estimated to be sufficiently stable, and the holder is used to hold and expose the wafer after the actual temperature difference between the wafer and the holder has substantially disappeared. The wafer hardly expands or contracts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a thin film magnetic head,
The present invention relates to an exposure method and an exposure apparatus used for manufacturing a micro device such as a semiconductor integrated circuit and a liquid crystal display.

[0002]

2. Description of the Related Art In a photolithography process which is one of semiconductor device manufacturing processes, an exposure apparatus for transferring a pattern formed on a mask (including a reticle) onto a substrate coated with a photoresist is used. A stepper for reducing and projecting an image of a pattern onto a shot area on a substrate is often used.

As a stepper, a step-and-repeat type in which a pattern is collectively transferred to a shot area on a substrate, and the substrate is sequentially moved and the collective transfer is repeated to another shot area, or recently, an exposure range From the viewpoint of enlargement of exposure and improvement of exposure performance, etc., the mask and substrate are moved synchronously to scan and scan with slit light of rectangular or other shape.
A step-and-scan method in which the pattern is sequentially transferred to a shot area on the substrate by illuminating, and the substrate is sequentially moved and scanning and exposure are repeated for another shot area has also been developed and put to practical use. It has become.

In this type of exposure apparatus, a substrate to be exposed is transferred to a transfer position (standby position) near a substrate holder by a substrate transfer device, and is mounted on the substrate holder by a transfer arm of the substrate transfer device. Placed on the substrate holder. In this state, the transfer exposure is repeated for each shot area while the substrate is step-moved by the stage on which the substrate holder is mounted.

[0005] After exposure processing for all shot areas is completed, the substrate is subjected to steps of development, etching, doping, and the like, and is again coated with a photoresist, and similar steps including exposure processing using another mask are sequentially performed. Repeated
Various elements are formed on the substrate. In addition,
In the specification of the present application, the first exposure processing on the substrate is sometimes referred to as first exposure, and the second or subsequent exposure processing on the substrate is sometimes referred to as second exposure.

Although the installation environment of the exposure apparatus (in a clean room) and the temperature control in the chamber covering the apparatus are strictly controlled as much as possible, there are limitations from the technical and cost viewpoints. There is also heat generation of the substrate due to the energy of the illumination light. For this reason, there is a problem that the exposure accuracy is deteriorated due to expansion and contraction (expansion or contraction) due to the temperature change of the substrate over time. This problem may be caused by a change in the temperature of the substrate during the exposure process from the first shot area to the last shot area of the same substrate, or a difference in the temperature or tendency of the temperature change between the first exposure and the second exposure. It is also caused by

Particularly, when a thin-film magnetic head used for a hard disk drive or the like is manufactured, a ceramic substrate is used as a substrate. Rate) is high, and the expansion and contraction force accompanying the temperature change is large, and the above-mentioned problem due to the temperature change is remarkable.

[0008]

For this reason, conventionally, after a substrate is put in a clean room, the substrate is allowed to stand sufficiently until the substrate temperature is stabilized, then put into a chamber and waited until the substrate is sufficiently stabilized. Similarly, after waiting until the substrate is sufficiently stabilized after the adsorption and holding, i.e., after uniformly waiting for the passage of time during which the temperature of the substrate is estimated to be sufficiently stable, the exposure process must be performed, and the throughput is reduced. There was a problem of causing a decline. On the other hand, if the waiting time is simply shortened, highly accurate pattern transfer cannot be performed due to expansion and contraction of the substrate. Although the temperature inside the clean room or the chamber is controlled, for example, ± 1 ° C
Due to the degree of variation, there is a case where there is a temperature difference between the two when the substrate is suction-held by the substrate holder, and expansion and contraction of the substrate based on this temperature difference may also adversely affect the exposure accuracy.

On the other hand, if a substrate made of a material having a small coefficient of thermal expansion is used, the waiting time can be shortened, and the throughput and accuracy can be improved. The degree of freedom is reduced, which is a constraint on the design and increases the cost.

Further, if the expansion and contraction tendency of the substrate at the time of the first exposure and the second exposure is different, the overlay accuracy of the pattern formed on the substrate at the time of the first exposure and the pattern formed at the time of the second exposure is deteriorated. In particular, when manufacturing a thin-film magnetic head, the straightness of the chip arrangement between shots is deteriorated, and the yield is reduced.

The present invention has been made in view of such problems of the prior art, and an object thereof is to reduce the throughput and improve the exposure accuracy. Another object of the present invention is to improve the pattern overlay accuracy.

[0012]

In the following description, in order to facilitate understanding, constituent elements of the present invention will be described with reference numerals shown in the drawings of the embodiments. Are not limited by these reference numerals.

1. To achieve the above object, claim 1
According to the exposure method of the present invention described above, the temperature of the photosensitive substrate (W) is measured, and after the measured temperature or the rate of change of the temperature falls within a preset allowable range, an exposure process is performed on the photosensitive substrate. It is characterized by the following.

According to the exposure method of the present invention, the exposure processing is performed when the actual temperature of the photosensitive substrate or the rate of change thereof becomes acceptable from the viewpoint of exposure accuracy. Therefore, compared to the conventional method in which the temperature of the photosensitive substrate is estimated to be sufficiently stable and waits uniformly, the waiting time wasted after the temperature of the photosensitive substrate is actually stabilized can be reduced, and the throughput can be reduced. Can be improved. Further, since the temperature of the photosensitive substrate is sufficiently stable, the photosensitive substrate is less likely to expand and contract during the exposure processing, and the exposure accuracy can be increased.

As the allowable range, for example, the target temperature of the temperature control in the chamber of the exposure apparatus is centered, or the temperature of the substrate holder for holding the photosensitive substrate detachably is different from the target temperature of the temperature control in the chamber. Is measured in advance in the relationship described above, and an average temperature can be set as a center to make the range allowable in accuracy.

In the exposure method according to the present invention, the temperature of the photosensitive substrate (W) is measured, and the temperature of the substrate holder (WH) for detachably holding the photosensitive substrate is measured. After the temperature difference between the temperature of the substrate holder and the temperature of the photosensitive substrate falls within a preset allowable range, an exposure process is performed on the photosensitive substrate.

According to the exposure method of the present invention, the exposure process is performed after the temperature difference between the photosensitive substrate and the substrate holder falls within a predetermined allowable range. Compared to the case where the temperature of the photosensitive substrate is estimated to be sufficiently stable and waiting uniformly, the waiting time wasted after the actual temperature difference between the photosensitive substrate and the substrate holder substantially disappears can be reduced, Throughput can be improved.

Further, the expansion and contraction of the photosensitive substrate is greatly affected by the relative temperature difference when the photosensitive substrate is held by the substrate holder. However, in this exposure method, the actual temperature difference between the photosensitive substrate and the substrate holder substantially disappears. Since the exposure process is performed after the exposure process, the photosensitive substrate hardly expands and contracts during the exposure process, and therefore, high exposure accuracy can be realized.

According to a third aspect of the present invention, in the exposure method, the temperature of the photosensitive substrate being transported is measured by a substrate transport device (38) which transports the photosensitive substrate (W) to a transfer position with the substrate holder (WH). After the measured temperature or the rate of change of the temperature falls within a preset allowable range, the exposure processing is performed by holding the photosensitive substrate on the substrate holder.

According to the third aspect of the present invention, the photosensitive substrate is transferred to the substrate holder after the temperature of the photosensitive substrate being conveyed toward the substrate holder or the rate of change thereof falls within a predetermined allowable range. Since the exposure process is performed by holding the photosensitive substrate, it is compared with the conventional case where the temperature of the photosensitive substrate is assumed to be sufficiently stable as in the conventional case, and after the temperature of the photosensitive substrate is actually stabilized. Unnecessary waiting time can be reduced, and throughput can be improved.

The expansion and contraction of the photosensitive substrate is greatly affected by the relative temperature difference when the photosensitive substrate is held by the substrate holder. For example, the allowable range is determined by setting the target temperature for controlling the temperature in the chamber of the exposure apparatus. If the temperature of the substrate holder is measured in advance in relation to the target temperature of the temperature control in the chamber as a center or the average temperature is set as a center and the temperature is set as an acceptable range in terms of accuracy, the temperature of the substrate holder and the photosensitive substrate is adjusted. After the difference substantially disappears, the photosensitive substrate is held by the substrate holder, so that the photosensitive substrate hardly expands and contracts during the subsequent exposure processing, and therefore, high exposure accuracy can be realized.

According to a fourth aspect of the present invention, in the exposure method, the temperature of the substrate holder (WH) for detachably holding the photosensitive substrate (W) is measured, and the substrate is transported and held on the substrate holder. The temperature of the photosensitive substrate being transported by the transport device (38) is measured, and after the temperature difference between the measured temperature of the substrate holder and the temperature of the photosensitive substrate falls within a preset allowable range, Is held by the substrate holder to perform an exposure process.

According to the exposure method of the present invention, after the temperature difference between the photosensitive substrate and the substrate holder falls within a predetermined allowable range, the exposure process is performed by holding the photosensitive substrate on the substrate holder. Therefore, compared to the conventional case where the temperature of the photosensitive substrate is assumed to be sufficiently stable as in the conventional case, the waste temperature is substantially reduced after the actual temperature difference between the photosensitive substrate and the substrate holder substantially disappears. Can be reduced and the throughput can be improved.

Further, the expansion and contraction of the photosensitive substrate is greatly affected by the relative temperature difference when the photosensitive substrate is held by the substrate holder, but after the actual temperature difference between the photosensitive substrate and the substrate holder substantially disappears, Since the photosensitive substrate is held after the exposure process is performed, the photosensitive substrate hardly expands and contracts during the exposure process, and therefore, high exposure accuracy can be realized.

2. The exposure method of the present invention according to claim 5,
By projecting an image of a pattern from the illuminated mask (64A) onto the photosensitive substrate while stepping the photosensitive substrate (W), a plurality of shot areas arranged in a matrix on the photosensitive substrate are formed. In the exposure method in which a pattern is transferred to the shot area, the exposure processing for each of the shot areas is started from a shot area located at the approximate center of each of the shot areas, and the exposure processing is performed on a shot area surrounding the start shot area. And the same applies to a shot area surrounding the shot area after the exposure processing.

According to a sixth aspect of the present invention, in the exposure method according to the fifth aspect, the exposure processing for each shot area is performed in an unexposed shot area not adjacent to the shot area immediately after the exposure processing. If there is
It is characterized in that it is performed on the non-adjacent shot areas.

According to the exposure method of the present invention described in claim 5 or 6, the order of the exposure processing of each shot area is started from the shot area located at the approximate center and sequentially outward in a generally concentric manner. Since the processing is performed, even if the photosensitive substrate expands and contracts due to a temperature change during a series of exposure processing from the first shot area to the last shot area, the arrangement of each shot area (shot arrangement) is changed. It can be evenly distributed as a whole.

3. The exposure method of the present invention according to claim 7,
The pattern is transferred to a plurality of shot areas on the photosensitive substrate by projecting an image of the pattern from the illuminated mask (64A) onto the photosensitive substrate while step-moving the photosensitive substrate (W). In the exposure method described above, the expansion characteristic of the photosensitive substrate due to the energy received by the photosensitive substrate is determined in advance by the exposure processing sequentially performed on each of the shot regions, and the first exposure is performed on each of the shot regions of the photosensitive substrate. At the time of the first exposure, the exposure processing is performed while correcting the image magnification for each shot area based on the expansion characteristic, and a reference mark is transferred to each shot area on the photosensitive substrate, and At the time of the second or subsequent exposure (at the time of the second exposure) for each shot area, the position of the reference mark is measured, and each shot is taken based on the measurement result. Obtains the amount of change in the size of the bets area, and performing an exposure process while correcting the image magnification of each shot area based on the variation amount.

Since the temperature of the photosensitive substrate expands by absorbing the energy of the illumination light, the expansion characteristic indicating the relationship between the cumulative irradiation time of the illumination light and the expansion of the photosensitive substrate is calculated in advance by theoretical calculation or actual measurement. When performing exposure processing for each shot area during the first exposure, the image magnification is corrected based on the cumulative illumination time of the photosensitive substrate from the exposure processing on the first shot area to that time and the expansion characteristic of the photosensitive substrate ( By successively performing the exposure processing while expanding, the size of each shot area can be made substantially equal regardless of the expansion of the photosensitive substrate due to illumination.

In addition, the reference marks are transferred during the first exposure, the positions of these reference marks are measured during the second exposure, and the image magnification is corrected (enlarged or reduced) to sequentially expose each shot area. Processing (second exposure)
The size of each shot area at the time of the first exposure and the second exposure becomes substantially equal,
Pattern overlay accuracy can be increased.

4. The exposure method of the present invention according to claim 8,
The pattern is transferred to a plurality of shot areas on the photosensitive substrate by projecting an image of the pattern from the illuminated mask (64A) onto the photosensitive substrate while step-moving the photosensitive substrate (W). In the exposure method described above, at the time of the first exposure to each shot area of the photosensitive substrate (at the time of first exposure), at least two reference marks separated from each other are transferred to each shot area on the photosensitive substrate. Then, at the time of the second or subsequent exposure (at the time of the second exposure) for each shot area of the photosensitive substrate, the positions of the reference marks are measured for a plurality of shot areas of the shot areas, and based on the measurement result, In addition to obtaining shot information that is at least one of the amount of change in the size and position of the shot area in which the reference mark was measured, The shot information of the shot area where the measurement of the reference mark is not performed is interpolated based on the shot information of the shot area where the measurement of the reference mark is performed, and these are used as correction data. And exposure processing is performed while correcting at least one of the image position and the image position.

At the time of the first exposure, the reference marks are transferred, and at the time of the second exposure, the positions of these reference marks are measured to correct the image magnification and / or the image position, thereby sequentially exposing each shot area (second exposure). The size of the shot area and / or the position (array) of the shot area during the first exposure and the second exposure
Become substantially equal, and the pattern overlay accuracy can be increased.

Here, the measurement of the reference mark at the time of the second exposure can be performed for all the shot areas. However, when the measurement is performed for all the shot areas, the processing time is delayed correspondingly, and the overall throughput is reduced. Will be. For this reason, in the present invention, the measurement of the reference mark can be intermittently performed as necessary, and the shot area where the measurement of the reference mark is performed is determined based on the measurement result. Can correct the image magnification and / or the image position based on the shot information obtained by interpolation based on the measurement result of the shot area where the measurement was performed. Thereby, it is possible to improve the pattern overlay accuracy while suppressing a decrease in throughput.

5. The exposure method according to the present invention according to claim 9,
The exposure method according to any one of claims 1 to 8,
The present invention is applied to an exposure apparatus for manufacturing a magnetic head.

According to a tenth aspect of the present invention, there is provided an exposure apparatus for manufacturing a magnetic head, wherein the exposure method according to any one of the first to eighth aspects is applied.

In an exposure apparatus for manufacturing a magnetic head,
As a photosensitive substrate, for example, a ceramic substrate having a large thickness, a large coefficient of thermal expansion and a large thermal expansion force as compared with a substrate for normal IC manufacturing, for example, a silicon substrate, is used, and the ceramic substrate is held by a substrate holder. After that, since it expands and contracts by overcoming the holding force with the temperature change, the decrease in the exposure accuracy due to the temperature change becomes more remarkable as compared with the case of the silicon substrate. Therefore, when the method of the present invention is applied to an exposure apparatus for manufacturing a magnetic head, the effect is remarkable.

[0037]

Embodiments of the present invention will be described below with reference to the drawings.

The overall configuration diagram 1 is a plan sectional view of an exposure apparatus according to an embodiment of the present invention,
2 is a cross-sectional view taken along the line AA shown in FIG. 1, FIG. 3 is a view showing details of the portion B shown in FIG. 1, FIG. 4 is a cross-sectional view taken along the line CC shown in FIG. FIG. 6 is a sectional view taken along the line EE shown in FIG. 5, and FIG.
Is a cross-sectional view taken along line FF shown in FIG. 3, FIG. 8 is an enlarged plan view showing another example of the sensor near the adjustment table shown in FIG. 1, and FIG. 9 is an enlarged plan view near the wafer stage shown in FIG. FIG.

As shown in FIGS. 1 and 2, an exposure apparatus 100 according to the present embodiment is a reduction projection type exposure apparatus for manufacturing a thin film magnetic head, and the apparatus main body is divided into a plurality of systems. Each is housed in the independent chamber 31, 32, 33.

In the first independent chamber 31, an air conditioner 34 composed of three independently operated air conditioners is provided.
Is installed. The air temperature-controlled by the first air-conditioning unit in the air-conditioner 34 is supplied to the first pipe 35A and the dust removal HEP installed on the ceiling of the second independent chamber 32.
The air is blown into the independent chamber 32 through the A filter 59A. As shown in FIG. 2, a return 60A is mounted on the floor of the independent chamber 32, so that clean air blown into the independent chamber 32 is supplied to the return 60A shown in FIG. 2 and the first air shown in FIG. It returns to the first air conditioning unit via the pipe 36A.

The air whose temperature has been adjusted by the second and third air conditioning units in the air conditioner 34 respectively flows through a second pipe 35B and a third pipe 35C, as shown in FIG. HEPA filter 59C installed on the ceiling of lower chamber 33A of chamber 33, and upper chamber 3
It is led to the HEPA filter 59B installed on the ceiling of 3B. Then, the air flowing down from the HEPA filter 59C to the lower chamber 33A and reaching the return 60C, and the air flowing from the HEPA filter 59B to the upper chamber 33A.
The air that has flowed down to B and reached the return 60B,
The air returns to the second and third air conditioning units via the second pipe 36B and the third pipe 36C, respectively.

Although not shown, the exposure apparatus body and
Chambers 32 and 33 for installing a wafer loader system and the like
A, 33B (for example, NH)_Four ⁺, SO
_Four ^2- ), Sulfur dioxide (SO_Two) Etc.
CAL filter with HEPA filters 59A-59C
Is preferably provided. As a result, ammonium sulfate
((NH_Four)_TwoSO_Four) Etc. will not be generated
This adheres to the optical elements constituting the illumination optical system and
Phenomenon that lowers the reflectance or transmittance of
The phenomenon that the cross-sectional shape of the turn becomes T-shaped can be prevented.
You. This chemical filter consists of three HEPA filters
What is necessary is just to provide corresponding to each of 59A-59C. However
And at least a HEPA filter 5 for the illumination optical system.
9A is provided with a chemical filter.
Chemical filters are used for the EPA filters 59B and 59C.
It may not be provided.

As shown in FIG. 2, the second independent chamber 3
An optical system of the exposure apparatus main body is installed in the apparatus 2. That is,
On the floor of the independent chamber 32, vibration isolation pads 37a and 37
b, an anti-vibration table 37 is installed, and the wafer stage 10 is installed on the anti-vibration table 37.
A wafer W having a photoresist applied thereon is loaded. The column 62 is mounted on the anti-vibration table 37, the projection optical system 63 is fixed in the middle of the column 62, and the reticle 64A is placed on the reticle holder at the upper end of the column 62.

As shown in FIG. 1, the wafer stage 10
Is composed of a base 9B, a Y stage 9Y, an X stage 9X, etc., and a wafer holder WH is held on the X stage 9X by vacuum suction. A wafer W, which is a ceramic substrate to be exposed, is held on a wafer holder WH by vacuum suction. A notch called an orientation flat (or notch) is formed in a part of the circular outer periphery of the wafer W, and the notch is oriented in a predetermined direction, and the center of the wafer W is aligned with the wafer holder WH.
So that the wafer holder W
The wafer W is loaded on H. In the present embodiment, a wafer loader system 38 for carrying in (loading) the wafer onto the wafer holder WH and carrying out (unloading) the wafer from the wafer holder WH is provided in the lower chamber 33A of the third independent chamber 33 (FIG. 2). (See Reference).

The guide portion of the wafer loader system 38 is composed of a horizontal slider body 39 extending in the X direction and a vertical slider body 48 extending in the Y direction.
The scalar robot hand 47 is slidably arranged in the direction. The scalar robot hand 47 includes an X-axis moving unit 41 that moves in the X direction along the horizontal slider main body 39, a Z-axis moving unit 42 that expands and contracts on the X-axis moving unit 41 in the Z direction perpendicular to the XY plane. A θ-axis rotating unit 43 that rotates about the center 42 a of the Z-axis moving unit 42, an R-axis rotating unit 44 rotatably provided at the tip of the θ-axis rotating unit 43, and a rotation at the tip of the R-axis rotating unit 44. Hand part 45 provided freely
The vacuum suction unit 46 is attached to the tip of the hand unit 45. By rotating the θ-axis rotating unit 43 about the center 42a, the hand unit 45 rotates in the θ direction,
By combining the rotation angles of the shaft rotating unit 44 and the hand unit 45, the position in the radial direction (R direction) from the center 42a of the hand unit 45 can be adjusted.

Further, storage shelves 22A and 55 for storing the wafers W are fixed on the mounting tables 21A and 54 provided on the side surfaces of the horizontal slider main body 39, respectively, and the wafers W are temporarily placed thereon. Tables 56A and 5 for storage
6B is installed. A plurality of (four in FIG. 1) pins for mounting a wafer are mounted on the temporary mounting tables 56A and 56B. The vicinity of the storage shelves 22A and 55, and the temporary storage 56
Openings 33d and 33e for exchanging storage shelves and the like from outside are provided on the side surfaces of the independent chamber 33 near A and 56B, respectively. A door frame unit equipped with an open / close door (not shown) is attached to these openings.

The hand unit 45 of the scalar robot hand 47 is protruded from the opening 33c on the left side of the independent chamber 33 to transfer the wafer W to an external device (such as an external photoresist coater or a developing device). The wafer W can be transferred at another position Q1. Further, by moving the scalar robot hand 47 to the position Q7 and protruding the hand portion from the opening 33f on the right side of the independent chamber 33,
The wafer W can be exchanged with the external device, and the wafer W can be exchanged at another position Q8.
Similarly, the scalar robot hand 47 is moved to the positions Q3 and Q3.
The wafer W can be transferred to the respective storage shelves 55, the temporary storage tables 56A or the temporary storage tables 56B by moving the wafers W to the storage racks 5 or Q6.

The vertical slider body 48 protrudes into the independent chamber 32 through the opening 32a on the side surface of the independent chamber 32 and the opening 33b on the side surface of the lower portion 33A of the independent chamber 33. Two sliders (transfer arms) 49A and 49B having a U-shaped contact portion of the wafer W are slidably mounted on the slider. These two sliders 49A and 49B hold the wafer W by their respective vacuum suction parts,
It moves independently between the independent chamber 32 and the lower chamber 33A. And the scalar robot hand 47
For example, after taking out the wafer W from the storage shelf 55, the wafer W is transferred to the slider 49A or 49B via the vertically movable turntable 52 at the position Q4. Thereafter, the scalar robot hand 47, which has similarly received the exposed wafer W from the slider 49A or 49B via the vertical movement of the turntable 52, returns the wafer W to, for example, the storage shelf 55.

The portion of the scalar robot hand 47 that comes into contact with the wafer W, such as the hand portion 45, the slider 49A, and the slider 49B, is formed of a conductive ceramic having a dense surface. However, a dense conductive ceramic may be applied to the surface of the contact portion with the wafer W by coating or the like.

Horizontal slider body 39 and vertical slider body 48
A sensor base 50 is installed in the vicinity of the area where the intersections of the two, i.e., near the position Q4, and a center position sensor (described later) for detecting the center position of the wafer W is arranged on the sensor base 50. An adjustment table 51 is arranged above the sensor table 50,
A conductive ceramic turntable 52 that rotates about an axis perpendicular to the XY direction is provided above the adjustment table 51, and the wafer is placed on the adjustment table 51 and at a position between the turntable 52 and the sensor table 50. A light emitting portion 53 of a notch detection sensor for detecting the position of a linear notch (orientation flat) on the outer periphery of W, and a line sensor 75 (see FIG. 2) composed of a one-dimensional CCD or the like are arranged. It is. The light projecting unit 53 irradiates the line sensor 75 with a non-photosensitive slit-shaped light beam to the photoresist on the wafer W, and the line sensor 75 detects a light-shielded portion of the slit-shaped light beam. , And outputs the detection result to a control system (not shown).

FIG. 3 is an enlarged view of a portion B in FIG. 1. In FIG. 3, when the wafer W is transferred from the scalar type robot hand 47 onto the turntable 52, the wafer W
First passes through the sensor base 50. As shown in FIG. 4 which is a cross-sectional view along the line CC in FIG. 3, four light emitting units 76A to 76D are installed on the upper part of the sensor base 50, and the light emitting units are provided on the lower part of the sensor base 50. Four light receiving sections 7 so as to face each other
8A to 78D are set in advance, and the wafer W is passed between the light emitting units 76A to 76D and the light receiving units 78A to 78D. Non-photosensitive beam-like illumination light is emitted from the light projecting units 76A to 76D to the photoresist on the wafer W.

In this case, as shown in FIG. 3, since the wafer W is substantially circular, light is emitted by the wafer W at the position of the wafer W in the direction of the turntable 52 and at each of the light receiving sections 78A to 78D in FIG. The control system (not shown) determines the center position of the wafer W from the relationship with the timing from when the light is shielded to when the light is received again. Then, the scalar robot hand 47 places the wafer W on the turntable 52 such that the center position of the wafer W matches the rotation center of the turntable 52. At this time, the slider 49A is moved to the back surface of the wafer W. Also, based on the center position information, the R of the scalar type robot hand 47
By controlling the axis and the θ axis (or the X axis), the wafer W is placed on the turntable 52 so that the centers match. Wafer W on turntable 52
Is vacuum-adsorbed. By such a positioning method, the center of the wafer W is positioned with respect to the center of the turntable 52 with an accuracy of about ± 0.2 mm.

When the turntable 52 is rotated in this state, the periphery of the wafer W is cut off by the light emitting portion 5 of the notch detection sensor.
3 rotates between the line sensor 75 and the line sensor 75 (see FIG. 2), and the length of the light blocking portion decreases when the notch (the orientation flat or the notch) of the wafer W passes over the line sensor 75. A control system (not shown) controls the wafer W
The position of the notch is detected. According to this detection result,
The rotation of the turntable 52 is stopped at a position where the notch of the wafer W faces the horizontal slider body 39, for example.
Thereafter, the suction of the wafer W by the turntable 52 is released, and the turntable 52 is lowered to move the slider 49A.
The wafer W is vacuum-sucked on the upper surface of the
Along the vertical slider body 48 as shown in FIG.
Then, the wafer W is transferred from the slider 49A onto the wafer holder WH by a wafer transfer means (not shown). At this time, the center of the wafer W and the position of the notch are exactly in a predetermined state, and the wafer W is placed on the wafer holder WH.

Further, there are generally concentric convex portions on the wafer holder WH, and the wafer W is mounted on these concentric convex portions. Therefore, it is desirable that the contact portions of the scalar robot hand 47 and the sliders 49A and 49B with the wafer W be different from the contact portions on the wafer holder WH. That is, the position of the back surface of the wafer in contact with the scalar robot hand 47 and the sliders 49A and 49B is different from the position of the back surface of the wafer in contact with the projection of the wafer holder WH. At this time, the scalar robot hand 47 and the wafers W of the sliders 49A and 49B are set in accordance with the shape of the convex portion of the wafer holder WH.
What is necessary is just to determine the position and the area of the contact part with. This allows
The flatness of the wafer W can be favorably maintained on the wafer holder WH. This is because even if foreign matter adheres to the back surface of the wafer W due to contact with the scalar robot hand 47 and the sliders 49A and 49B, the foreign matter is not trapped between the convex portion of the wafer holder WH and the wafer W. It is.

Note that, instead of the line sensor 75 in FIG. 2, an analog sensor in which a cylindrical lens and one light receiving element (for example, a photodiode) are combined may be used. When this analog sensor is used, the amount of light received by the light receiving element changes according to the length of the light shielding portion formed by the wafer W, so that the length of the light shielding portion can be detected.
Further, two sets of combinations of the light projecting unit 53 and the analog sensor are arranged at two positions in the circumferential direction of the wafer W, and the turntable 52 is servo-controlled so that the output signals of the two analog sensors can be balanced. The notch (orientation flat or notch) of wafer W may be positioned by fixing the rotational position of.

As shown in FIG. 3, a light guide 77 for guiding light obtained by separating a part of the exposure light for illuminating the reticle is arranged above the adjustment table 51. FIG.
FIG. 7 is a cross-sectional view taken along the line FF of FIG. 3. As shown in FIG. 7, the emission end 77 a of the light guide 77 is attached to the upper end of the U-shaped movable base 85. A line sensor 84 composed of a one-dimensional CCD is fixed to the lower end portion so as to face the emission end 77a, and the slider 85a fixed to the bottom surface of the moving table 85 is placed on a support table 86 fixed to the adjustment table 51. Installed in the guide section. A drive motor 87 is fixed to the support base 86, and a slider 85 is
A feed screw 88 is screwed in parallel with the sliding direction of a, and the feed screw 88 is connected via a rotary shaft coupling 89 of the drive motor 87. The moving direction of the moving table 85 is a radial direction around the turntable 52, and the driving motor 87
, The moving table 85 can be moved in the radial direction.

At the time of the so-called peripheral exposure, a slit-shaped photoresist for exposing the photoresist applied on the wafer W to the peripheral portion of the wafer W adsorbed on the turntable 52 from the emission end 77a of the light guide 77. The exposure light is irradiated, and the line sensor 84 detects the length of the light-shielding portion of the exposure light, and supplies the detection result to a control system (not shown). The peripheral exposure refers to exposing only the photoresist on the peripheral portion of the wafer W to prevent dust from being generated from the peripheral portion of the wafer W. In this case, in the present embodiment, since the rotation center of the turntable 52 and the center of the wafer W almost exactly match, the position of the moving table 85 is adjusted to emit the exposure light from the emission end 77a. In addition, the width of the peripheral exposure of the wafer W can be accurately set to a desired value. In addition, since the notch position of the wafer W is known, when a motor with an encoder or a stepping motor is adopted for the turntable 52 and the notch portion of the wafer W reaches between the emission end 77a and the line sensor 84, By adjusting the position of the moving table 85 so that the width of the peripheral exposure becomes constant, the peripheral exposure can be performed with a constant width even in the notch portion of the wafer W.

As shown in FIG. 2, a reticle loader system 65 is provided on a return 60B in a chamber 33B above the independent chamber 33. The guide portion of the reticle loader system 65 is composed of a vertical slider body 72 protruding into the independent chamber 32 through an opening 32b of the independent chamber 32 and an opening 33g of the upper chamber 33B. Sliders 73A and 73B are attached. Then, the vertical slider body 72
A base 66, a Z-axis moving unit 67 that expands and contracts in the Z direction perpendicular to the XY plane on the base 66,
A θ-axis rotating section 68 that rotates about the center of the Z-axis moving section 67, an R-axis rotating section 69 rotatably provided at the tip of the θ-axis rotating section 68, and a tip of the R-axis rotating section 69 And a scalar type robot hand including a hand unit 70 rotatably provided.

Further, a reticle storage shelf 74 is set near the scalar type robot hand for the reticle, and the hand unit 7 of the scalar type robot hand is placed from the storage shelf 74.
At 0, the reticle is taken out by vacuum suction, and the reticle thus taken out is transferred to the slider 73A or 73B of the vertical slider body. Then, the slider 73A or 73B
Moves along the vertical slider main body 72 into the independent chamber 32 while holding the reticle by vacuum suction, and places the reticle on the reticle holder on the column 62 of the exposure apparatus main body via a reticle delivery means (not shown). Is installed. When replacing the reticle, the reticle taken out of the reticle holder is returned to the storage shelf 74 via the slider 73A or 73B and the scalar robot hand for the reticle. Thus, the reticle loader system 65 is simplified because the scalar robot hand is also used when transferring the reticle.

Further, in FIG. 2, a lower chamber 33 of the second independent chamber 32 and the third independent chamber 33 is shown.
A and vacuum pumps 61A, 61C and 61B are installed in A and the upper chamber 33B, respectively. The vacuum pump 61A supplies a negative pressure for vacuum suction to the wafer W in the exposure optical system in the independent chamber 32, and
1C supplies a negative pressure for vacuum suction on the wafer W in the wafer loader system 38 in the chamber 33A, and a vacuum pump 61B supplies a negative pressure for vacuum suction on the reticle in the reticle loader system 65 in the chamber 33B. I do. As described above, in the present embodiment, vacuum suction in the exposure apparatus body,
Since the vacuum suction by the wafer loader system 38 and the vacuum suction by the reticle loader system 65 are performed independently, there is an advantage that the influence of the suction or separation of the wafer W is not transmitted to each other.
Further, while the reticle pattern is being transferred to the wafer W sucked on the wafer holder WH of the exposure optical system in the independent chamber 32, the vacuum suction is turned on or off by the wafer loader system 38 and the reticle loader system 65. However, since there is no pressure fluctuation on the wafer holder WH side, there is an advantage that the wafer W does not shift.

Next, the configuration of the storage shelf 55 in FIG. 1 will be described in detail with reference to FIGS. FIG. 5 is a view as seen from the direction of arrow D in FIG. 1. As shown in FIG. 5, the storage shelf 55 is a box made of a conductive material and has a structure in which the front and rear portions are missing. I have. Further, partition plates 79 ₁ , 79 ₂ ,... Made of a conductive material are sequentially arranged between the top plate and the bottom plate 79 _N of the box body. As a result, N wafers W can be stored in the storage shelf 55. An example of N wafers is (2)
5 × n + 1), that is, 26, 51, 76, etc. Alternatively, when n = 0, N is one.

The storage shelf 55 is mounted on the mounting table 54 by screws.
The partition plate 79 in the storage shelf 55 is fixed by a stopper.₁above
Are three conductive ceramic pins 80A, 81A,
82A is planted. Similarly, other partition plates 79_Two,
79_Three,.. And bottom plate 79_N3 conductors each on top
Plant pins made of conductive ceramics. For example, one lot
When the wafer W is exposed, 79₁, 79_Two,
..And bottom plate 79_NOn top of each wafer W₁, W_Two・
・ ・ 、 W_NIs installed. Then, for example, the wafer W
₁Is carried out from the storage shelf 55, the EE line shown in FIG.
As shown in FIG.
Hand 45 of the hand 47 ₁Back and partition of
Ripper 79₁And the wafer W₁Take
put out.

In this case, in this embodiment, the number of wafers in one lot at the time of normal exposure is 25 × n, so that one more wafer can be stored in the storage shelf 55 of this embodiment. However, the number of sheets that can be stored extra may be plural. The extra storage portion includes, for example, a reference wafer with high flatness accuracy for measuring flatness on a wafer holder WH (see FIG. 1), a master wafer for self-measurement of the apparatus, or a wafer for cleaning a contact portion of a wafer. store. In the present embodiment, such extra space can be stored in the storage shelf 55.
, For example, as shown in FIG.
An independent stand such as A, 56B may be used.

Next, since the storage shelf 55 of the present embodiment has the front and rear portions missing, it is possible to pass the inspection light from the front and rear. Therefore, as shown in FIG. 1, the light projecting device 57 and the light receiving device 58
Place. When there is no wafer W in the storage shelf 55, the light beam emitted from the light projector 57 is
5 and is received by the light receiver 58. When the wafer W is present, its light beam is blocked. Thus, the presence or absence of the wafer W in the storage shelf 55 can be checked. Further, even if there is a wall behind the storage shelf 55, this function can be achieved if the wall is transparent.

As shown in FIG. 5, the storage shelf 55 is fixed on the installation table 54 by screwing, but the storage shelf 55 may be fixed by an openable and closable lock mechanism. By having such a lock mechanism, the mounting table 5
5, a conventional storage shelf 22A for process wafers (FIG. 1)
Can also be fixed. In the embodiment described above,
As shown in FIG. 3, the center position of the wafer W and the position of the notch (orientation flat or notch) are respectively detected by the detector in the sensor base 50 and the notch sensor including the light projecting unit 53. Was. However, as shown in FIG. 8, light emitting units 90A to 90D for irradiating a slit-shaped light beam downward are fixed at four positions above the adjustment table 51, and opposed to these light emitting units 90A to 90D, Further, the line sensor may be arranged so as to sandwich the peripheral portion of the wafer W. In this case, the position of the hand unit 45 of the scalar robot hand is driven by the servo method in the R direction, the θ direction, or the X direction so that the edge of the wafer W is at a predetermined position on each line sensor. Thus, the center position of the wafer W can be roughly positioned at the center position of the turntable 52.

Further, by using a combination of the four light emitting portions and the line sensor, for example, the light emitting portion 90A and a line sensor facing the light emitting portion 90A, a notch (orientation flat or notch) of the wafer W can be formed. Detection can also be performed. In this case, no matter in which direction the notch on the wafer W is oriented, four line sensors are provided, so that the position of the notch can be detected only by rotating the wafer W by about 90 ° at the maximum. Note that the same positioning is possible if there are two or more combinations of the light projecting unit and the line sensor.

FIG. 9 is an enlarged plan view of the vicinity of the wafer stage in FIG. Wafer stage 10 (X stage 9
X) A first temperature sensor 111 for detecting the temperature of the wafer holder WH is attached to the wafer holder WH held by suction. A loading slider (here, 49A is used for loading (loading), of the two sliders 49A and 49B of the vertical slider body 48,
A second temperature sensor 112 for detecting the temperature of the wafer W sucked and held by the slider 49A is attached to 49B for unloading (unloading). As shown in FIG. 3, a third temperature sensor 113 for detecting the temperature of the wafer W held by suction on the turntable 52 is provided on the turntable 52, as shown in FIG. The unit 45 has a fourth temperature sensor 114 for detecting the temperature of the wafer W held by suction.
Although not shown in detail, the storage shelves 22A and 55 are respectively provided with fifth temperature sensors (115) for detecting the respective temperatures of the wafers W stored therein. As the first to fifth temperature sensors 111 to 115, various types can be adopted. For example, a resistance temperature detector, a thermistor, a thermocouple, or the like can be adopted. Note that these first to fifth temperature sensors 111 to 115 are
It can be selectively provided according to the content of the processing described later.

[0068] Control system Figure 10 is a block diagram showing a main configuration of a control system of the exposure apparatus. The control system 120 includes a main control unit 121 that performs overall control, and a memory 1 that stores and holds various data.
22, an input unit 123 for inputting various data as needed by an operator or the like, a wafer loader control unit 124 for controlling the transfer of the wafer W by the wafer loader system 38, a reticle loader for controlling a reticle transfer by the reticle loader system 65. The control unit 125 is provided. In addition, the control system 120 includes an exposure control unit 126 that controls the movement control of the wafer stage 10 and the reticle stage, the lighting and light amount control of the illumination optical system, the exposure processing including the alignment processing, the leveling processing, and other processing. . The detection signals of the first to fifth temperature sensors 111 to 115 are input to the main control unit 121.

The memory 122 has an area for storing data indicating an allowable range of the temperature and the rate of change of the temperature. The operator can arbitrarily rewrite data indicating the permissible range (permissible range data) using an input unit (for example, a keyboard) as necessary. These allowable range data are predetermined and set in relation to the target temperatures in the chambers 32 and 33 by the air conditioner 34 and their variations. Here, as the allowable range data for the temperature, 20 ± 0.
2 ° C. is ± 0.2 ° C./sec as the allowable range data for the temperature change rate, and ± 0.2 ° C./sec is the allowable range data for the temperature difference between the wafer holder WH and the wafer W.
It is assumed that 2 ° C. is set in advance.

1. Processing Related to Wafer Temperature Detection and the Like Next, processing related to wafer temperature detection, wafer transfer, exposure timing, and the like by the control system 120 will be described with reference to a flowchart. Hereinafter, a plurality of processes (first to sixth processes) will be described. However, the adoption is optional, and one of them is fixedly adopted. However, all or a plurality of processes may be performed so that an operator or the like can arbitrarily select according to required accuracy or the like. These processes can be applied to both the first exposure and the second exposure.

(1) First Process FIG. 11 is a flowchart showing a first process performed by the control system. The first process is performed after the slider 49A sucks and holds the wafer W.
The processing until the exposure processing is performed is shown. When the first process is adopted, only the first temperature sensor 111 and the second temperature sensor 112 are essential, and the third, fourth, and fifth temperature sensors 113, 114, and 115 are not essential.

First, the wafer W sucked and held by the hand unit 45 of the scalar type robot hand 47 and transferred is subjected to pre-alignment or the like by a turntable 52 or the like, and thereafter, the slider 49A sucks and holds the wafer W. I do. In this state or while moving the slider 49A toward the wafer holder WH, the second temperature sensor 112
Thus, the current temperature of the wafer W held by suction is detected (ST1). Before, after or simultaneously with this, the temperature of the wafer holder WH is detected by the first temperature sensor 111 (ST2).

Next, the permissible range data for the temperature difference stored in the memory 122 is read (ST).
3) calculating a temperature difference between the temperature detected by the first temperature sensor 111 and the temperature detected by the second temperature sensor 112, and determining whether or not this temperature difference is within an allowable range indicated by the allowable range data; Is determined (ST4).

If it is determined in ST4 that the temperature difference between the wafer W and the wafer holder WH is not within the allowable range,
Returning to ST1, if it is determined that the temperature difference is within the allowable range, the wafer W is transferred to a transfer position near the wafer holder WH, transferred to the wafer holder WH, and suction-held by the wafer holder WH (ST5). . Then, while sequentially setting each shot area of the wafer W to the pattern projection position by the projection optical system by the wafer stage 10,
An exposure process is performed (ST6).

According to the first process, wafer holder WH
After the temperature difference between the wafer W and the wafer holder WH immediately before being sucked and held by the wafer holder WH falls within a preset allowable range, the wafer W is held by the wafer holder WH and the exposure process is performed. After the actual temperature difference has substantially disappeared, the wafer W
H, the temperature of the wafer W and the temperature of the wafer holder WH are substantially the same, so that the wafer W does not expand or contract during the exposure processing. Therefore, the size of each shot region is different and the shot arrangement is less distorted, and high exposure accuracy can be realized.

(2) Second Processing FIG. 12 is a flowchart showing the second processing by the control system. The second processing is performed after the slider 49A sucks and holds the wafer W.
The processing until the exposure processing is performed is shown. When the second process is employed, only the first temperature sensor 111 is essential, and the second, third, fourth, and fifth temperature sensors 112, 113, 114, and 115 are not essential.

First, the wafer W sucked and held by the hand unit 45 of the scalar type robot hand 47 and transferred is subjected to pre-alignment or the like by a turntable 52 or the like, and thereafter, the slider 49A sucks and holds the wafer W. I do. Next, the slider 49A is moved to the wafer holder WH.
, The wafer W is positioned at a transfer position near the wafer table 10, the wafer W is transferred to the wafer holder WH, and the wafer W is sucked and held by the wafer holder WH (ST1). Then, the first temperature sensor 111
Thus, the temperature of the wafer holder WH or the rate of change of the temperature per predetermined time is detected (ST2).

Next, the permissible range data on the temperature or the permissible range data on the rate of change of the temperature per predetermined time stored in the memory 122 is read (S
T3) It is determined whether or not the temperature detected by the first temperature sensor 111 or the rate of change of the temperature is within the allowable range indicated by the corresponding allowable range data (ST4).

If it is determined in ST4 that the temperature or the rate of change of the temperature detected by the first temperature sensor 111 is not within the corresponding allowable range, the process returns to ST2, and the temperature or the rate of change of the temperature corresponds. If it is determined that the shot area is within the allowable range, the exposure process is performed while sequentially setting each shot area of the wafer W to the projection position of the pattern by the projection optical system by the wafer stage 10 (ST5).

FIG. 13 is a diagram showing a change in the temperature of the wafer holder WH (the temperature detected by the first temperature sensor) before and after the wafer W is suction-held by the wafer holder WH when performing the second processing. If there is a temperature difference between the temperature of the wafer W and the temperature of the wafer holder WH immediately before being held by the wafer holder WH (the temperature of the wafer W is assumed to be high), the temperature of the wafer holder WH immediately after the wafer W is sucked and held by the wafer holder WH. Rises sharply and falls gradually after a peak. When this temperature falls within a predetermined allowable range (T ± ΔTe: 20 ± 0.2 ° C. in this embodiment), the exposure processing is started.

According to the second process, the exposure process is performed after the temperature of the wafer holder WH holding the wafer W by suction or the rate of change of the temperature falls within a predetermined allowable range. Exposure can be performed after the temperature of WH is sufficiently stabilized,
Is small, the expansion and contraction of the wafer W during the exposure processing is reduced. Therefore, the size of each shot region is different and the shot arrangement is less distorted, and high exposure accuracy can be realized.

(3) Third Process FIG. 14 is a flowchart showing a third process by the control system. After the slider 49A sucks and holds the wafer W,
The processing until the exposure processing is performed is shown. When the third process is employed, only the second temperature sensor 112 is essential, and the first, third, fourth, and fifth temperature sensors 111, 113, 114, and 115 are not essential.

First, the wafer W sucked and held by the hand unit 45 of the scalar type robot hand 47 and transferred is subjected to pre-alignment or the like by a turntable 52 or the like, and thereafter, the slider 49A sucks and holds the wafer W. I do. In this state or while moving the slider 49A toward the wafer holder WH, the second temperature sensor 112
Thus, the temperature of the wafer W held by suction or the rate of change of the temperature per predetermined time is detected (ST1).

Next, the permissible range data on the temperature or the permissible range data on the rate of change of the temperature per predetermined time stored in the memory 122 is read (S
T2) It is determined whether or not the temperature detected by the second temperature sensor 112 or the rate of change of the temperature is within the allowable range indicated by the corresponding allowable range data (ST3).

If it is determined in ST3 that the temperature detected by the second temperature sensor 112 or the rate of change of the temperature is not within the corresponding allowable range, the process returns to ST1 and the temperature or the rate of change of the temperature corresponds. If it is determined that it is within the allowable range, the wafer W is transferred to a transfer position near the wafer holder WH (ST4), transferred to the wafer holder WH, and suction-held by the wafer holder WH (ST).
5). Thereafter, an exposure process is performed while sequentially setting each shot area of the wafer W to a pattern projection position by the projection optical system using the wafer stage 10 (ST6).

According to the third process, wafer holder WH
After the temperature of the wafer W or the rate of change of the temperature immediately before the wafer W is sucked and held in the predetermined allowable range, the wafer W is sucked and held by the wafer holder WH to perform the exposure process. The temperature difference between the wafer W and the wafer holder WH at the time when the wafer W is sucked and held is small and stable, and the wafer W is less likely to expand and contract during the exposure processing. Therefore, the size of each shot region is different and the shot arrangement is less distorted, and high exposure accuracy can be realized.

(4) Fourth Process In the above-described third process, the temperature or the rate of change of the temperature of the wafer W sucked and held by the slider 49A is detected, and the process is performed based on this. The fourth process is
The temperature or the rate of change in the temperature of the wafer W sucked and held on the turntable 52 is detected by a third temperature sensor 113 attached to the turntable 52, and after the temperature falls within a predetermined allowable range, the subsequent transfer or the like is performed. Is performed. The other steps are the same as the above-described third processing, and a description thereof will be omitted. When the fourth process is adopted, only the third temperature sensor 113 is essential, and the first, second, fourth, and fifth temperature sensors 111, 112, 1
14, 115 are not essential.

According to the fourth process, the wafer W being transferred is
After the temperature of the wafer W or the rate of change of the temperature falls within a preset allowable range, the subsequent transfer is performed. Therefore, when the wafer W is sucked and held on the wafer holder WH, the temperatures of the wafer W and the wafer holder WH are changed. The difference is small and sufficiently stable, and the expansion and contraction of the wafer W during the exposure processing is reduced. Therefore, the size of each shot region is different and the shot arrangement is less distorted, and high exposure accuracy can be realized.

The allowable range of the temperature and the like in the case of adopting the fourth process is determined in consideration of the time required for transferring the wafer W from the position where the temperature is detected to the wafer holder WH. To 3rd processing can be set to be looser than the allowable range.

(5) Fifth Process In the third process described above, the temperature or the rate of change of the temperature of the wafer W sucked and held by the slider 49A is detected, and the process is performed based on this. The fifth processing is
The temperature of the wafer W or the rate of change of the temperature of the wafer W held by the suction unit 46 of the scalar robot hand 47 is determined by the hand unit 4.
4th temperature sensor 11 attached to 5 (adsorption failure 46)
4, after detecting a predetermined allowable range, processing such as subsequent conveyance is performed. The other steps are the same as the above-described third processing, and a description thereof will be omitted.
When the fifth process is adopted, only the fourth temperature sensor 114 is indispensable, and the first, second, third and fifth temperature sensors 114 are required.
The temperature sensors 111, 112, 113, 115 are not essential.

According to the fifth process, the wafer W being transferred is
After the temperature of the wafer W or the rate of change of the temperature falls within a preset allowable range, the subsequent transfer is performed. Therefore, when the wafer W is sucked and held on the wafer holder WH, the temperatures of the wafer W and the wafer holder WH are changed. The difference is small and sufficiently stable, and the expansion and contraction of the wafer W during the exposure processing is reduced. Therefore, the size of each shot region is different and the shot arrangement is less distorted, and high exposure accuracy can be realized.

The allowable range of the temperature and the like in the case where the fifth process is adopted is determined in consideration of the time required to transfer the wafer W from the position where the temperature is detected to the wafer holder WH. To 4th processing can be set to be looser than the allowable range.

(6) Sixth Process In the third process described above, the temperature or the rate of change of the temperature of the wafer W sucked and held by the slider 49A is detected, and the process is performed based on this. The sixth processing is
The temperature or the rate of change of the temperature of the wafer W stored in the storage shelf 22A or 55 is detected by the fifth temperature sensor (115) attached to the storage shelf 22A or 55, and the temperature falls within a predetermined allowable range. Later, processing such as subsequent transportation is performed. The other steps are the same as the above-described third processing, and a description thereof will be omitted. When the sixth processing is adopted, only the fifth temperature sensor 115 is essential, and the first, second, third and fourth temperature sensors 111 and 11 are used.
2, 113 and 114 are not essential.

According to the sixth process, after the temperature or the rate of change of the temperature of the wafer W stored in the storage rack 22A or 55 falls within a preset allowable range, the wafer W is unloaded from the storage rack 22A or 55. Is performed, the temperature difference between the wafer W and the wafer holder WH is small and sufficiently stable when the wafer W is sucked and held on the wafer holder WH, and the wafer W may expand and contract during the exposure processing. Less. Therefore, the size of each shot region is different and the shot arrangement is less distorted, and high exposure accuracy can be realized.

The allowable range of the temperature and the like in the case of adopting the sixth process is determined in consideration of the time required for transferring the wafer W from the position where the temperature is detected to the wafer holder WH. To the fifth process can be set to be looser than the allowable range.

2. Processing Related to Exposure Order of Shot Areas This processing is a part of the exposure processing performed by the exposure control unit 126, and relates to the order of a series of exposure processing sequentially performed on each shot area on the wafer W.
It can be used together with one of the above-mentioned first to sixth processes, or can be performed completely independently. This processing can be applied to both the first exposure and the second exposure.

FIGS. 15A and 15B are views showing the exposure order for each shot area. FIG. 15A shows the conventional exposure order, and FIG. 15B shows the exposure order according to the present invention. Note that, in this drawing, the numbers given in the shot areas S indicate the exposure order. Each of these shot areas S is arranged in a matrix, but conventionally, as shown in FIG. 1A, starting from a corner shot area (1), in a row direction (horizontal direction). Shot areas adjacent to each other (2, 3)
When one line is completed, the process moves to an adjacent line, and the exposure is performed in the opposite direction (4, 5, 6), and thereafter, the same exposure is performed (7, 8, 9). However, in such an exposure sequence, when the wafer W expands and contracts due to a temperature change, the shot arrangement is largely distorted, and the shot regions are not uniformly dispersed as a whole.

Therefore, as shown in FIG. 9B, in this embodiment, the exposure processing for each shot area S is performed from the shot area (1) located at the approximate center of each shot area. Starting, the operation is performed on the shot areas (2 to 9) surrounding the start shot area, and the same is performed on the shot areas (not shown) surrounding the shot areas (2 to 9) after the exposure processing. I did it. That is, the exposure is performed so as to draw a substantially concentric circle from the center. In this case, when there is an unexposed shot area that is not adjacent to the shot area immediately after the exposure processing, the exposure processing for each shot area S can be performed on the non-adjacent shot area. A shot area located at a position that is as symmetrical as possible with respect to the shot area (1) (for example, (2) and (3), (3) and (4), (4) and (5)) Can be performed sequentially. Note that the exposure processing may be performed while starting from the central shot area (1) and sequentially moving outward so as to form a spiral.

As described above, the order of the exposure processing of each shot area is started from the shot area located at the approximate center, and the processing is sequentially performed outward in a substantially concentric manner. Even when the wafer W expands and contracts due to a temperature change during a series of exposure processing up to the last shot area, the shot arrangement is small and the shot areas can be evenly dispersed. It is possible to increase the accuracy.

3. Processing for Thermal Expansion Due to Wafer Illumination This processing is a part of the exposure processing by the exposure control unit 126 and relates to correction for expansion of the wafer W due to illumination, and is one of the first to sixth processings described above. They can be used in combination or can be performed completely independently. This processing can be applied to both the first exposure and the second exposure.

The wafer W is illuminated by the illumination light during the exposure of each shot area, thereby absorbing a part of its energy and expanding by its heat. Therefore, the size of each shot area from the first exposed shot area to the last exposed shot area gradually decreases, and the distance between adjacent shot areas also tends to be narrower.

Here, the amount of expansion of the wafer W due to the energy received from the illumination light can be obtained by theoretical calculation or by actually irradiating the wafer W with the illumination light and actually measuring its elongation. This value is stored and held as correction data in relation to the illumination time, and exposure processing is performed on each shot area while correcting the image magnification and / or image position by the projection optical system using the correction data. That is, as the number of exposed shot areas increases, the image magnification and / or the interval between shot areas is increased. As a result, the size of all shot areas from the first shot area to the last shot area can be made substantially uniform, the shot areas are evenly distributed, and the shot arrangement becomes appropriate without distortion. can do.

4. Processing for Improving Overlay Accuracy The following processing is processing for improving the overlay accuracy of each shot area during the first exposure and the second exposure. It can be used in combination with one or both of the above-described processing for thermal expansion caused by illumination of the wafer and processing for detecting the temperature of the wafer.

As shown in FIG. 16, at the time of the first exposure, two reference marks (for example, diffraction grating marks) WM1 and WM are provided for each shot area S on the wafer W.
Transfer 2 The reference marks WM1 and WM2 are formed by transferring an image of a reference mask pattern formed along with the reticle pattern. This reference mark WM
1, WM2 can be used also as a normal alignment mark without special formation. The number of reference marks transferred at the time of the first exposure is not limited to two, but may be three or more. In particular, when high precision is required, a total of four points can be obtained, two points in the X direction and two points in the Y direction.

FIG. 18 is a flowchart showing the processing at the time of the second exposure by the control system, and shows the processing from the time when the slider 49A sucks and holds the wafer W until the exposure processing is completed.

First, the wafer W sucked and held by the hand unit 45 of the scalar type robot hand 47 and transferred is subjected to pre-alignment or the like by a turntable 52 or the like, and thereafter, the slider 49A sucks and holds the wafer W. I do. Next, the slider 49A is moved to the wafer holder WH.
, The wafer W is positioned at a transfer position near the wafer table 10, the wafer W is transferred to the wafer holder WH, and the wafer W is sucked and held by the wafer holder WH (ST1).

Next, search alignment is performed, and thereafter, the reference marks WM1 and WM2 are measured for each shot area S (ST2). This measurement is performed in the same manner as the measurement of a normal alignment mark. In other words, although not shown, the exposure apparatus includes an LIA (laser interference alignment) alignment system, an off-axis alignment system, and the like, and the positions of the reference marks WM1 and WM2 are detected by these. You. Where LIA
The method irradiates a diffraction grating mark on the wafer W with two coherent light beams, and performs position detection based on the phase of interference light composed of a pair of diffracted lights generated in the same direction from the diffraction grating mark. It is a method to perform. The off-axis method is a method of detecting a mark on the wafer W by a microscope provided at a fixed distance from the projection optical system.
It is also used for positioning the two light beams of the IA system and the diffraction grating mark on the wafer W. Note that the reference marks WM1 and WM2 are not limited to diffraction grating marks, and the measurement method is not limited to the above method, and may be another method.

The measurement of the positions of the reference marks WM1 and WM2 can be performed for all the shot areas S. However, from the viewpoint of preventing a decrease in the throughput, several shots that can represent the entirety from all the shot areas S are measured. It is preferable to select and measure only the selected shot area. For example, as shown in FIG.
Measurement is performed by selecting (1, 5, 9) from all shot areas (1 to 9).

Next, the measured reference marks WM1, WM2
A shot magnification (scaling value) for the shot area is calculated based on the distance between the shot areas (ST3). Thereafter, as shown in FIG. 17, the shot magnification for the shot areas (2, 3, 4, 6, 7, 8) where the measurement of the reference mark was not performed is changed to the shot areas (1, 5, 5) where the measurement was performed. It is determined by interpolation based on the shot magnification of 9) (ST4). The interpolation method can use a first-order approximation, but may use a second-order approximation.
The shot magnification for each of these shot areas is stored as correction data in the memory (122) (ST).
5).

Thereafter, the correction data corresponding to the shot area to be exposed is taken out, and based on the correction data, the image magnification is corrected so as to be substantially the same size as the shot area at the time of the first exposure (ST6). ), Exposure processing is started (ST7). If the exposure processing for one shot area has been completed, it is determined whether the exposure processing has been completed up to the last shot area (ST8), and if not, while performing the correction according to the corresponding correction data. The exposure process is repeated (ST6, 7, 8).

Although the above description has been made on the assumption that the image magnification is corrected only, the first exposure of each shot area is additionally or independently performed based on the measured positions of the reference marks WM1 and WM2. Calculate the deviation from the shot position at the time, store and hold this as correction data, take out the correction data corresponding to the shot area to be exposed at the time of the second exposure, based on the correction data,
The exposure process can be performed by correcting the image position so that the shot position is substantially the same as the shot position at the time of the first exposure.

As described above, according to this embodiment,
The sizes and positions of the shot areas at the time of the first exposure and the second exposure become substantially equal, and the accuracy of pattern superposition can be increased.

Note that such correction processing for each shot area can be used together with processing based on the EGA (Enhanced Global Alignment) method.
In this case, instead of forming the reference marks WM1 and WM2 specially on the wafer W, an alignment mark formed on the wafer W is used in order to apply the EGA method. If it is necessary to interpolate and calculate the shot magnification and the like of each shot area based on the position of the alignment mark intermittently measured for the necessity of the application of the above, the decrease in throughput can be suppressed as much as possible.

Here, the EGA method means that after the positions of alignment marks attached to a plurality of shot areas on a wafer W are intermittently measured, the offset of the center position of the wafer W, the degree of expansion and contraction of the wafer W, the wafer W Are determined by a statistical method on the basis of the difference between the set position of the mark and the measured position of the mark. In this method, the position of a shot area to be subjected to overlay exposure is corrected from a set position based on the value, and the wafer stage is sequentially stepped.

Note that the present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention. For example, the apparatus main body accommodated in the chamber is not limited to a reduction projection exposure apparatus for a thin film magnetic head, but may be a liquid crystal exposure apparatus that exposes a liquid crystal display element pattern to a square glass plate, and other exposure apparatuses. Is also good.

[0116]

As described above, according to the present invention, the throughput can be reduced and the exposure accuracy can be improved. In addition, the pattern overlay accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is a plan sectional view of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA shown in FIG.

FIG. 3 is a diagram showing details of a portion B shown in FIG. 1;

FIG. 4 is a sectional view taken along the line CC shown in FIG.

5 is an arrow view of the storage shelf shown in FIG. 1 as viewed from a direction D.

FIG. 6 is a sectional view taken along line EE shown in FIG. 5;

FIG. 7 is a sectional view taken along line FF shown in FIG. 3;

FIG. 8 is an enlarged plan view showing another example of the sensor near the adjustment table shown in FIG. 1;

FIG. 9 is an enlarged plan view of the vicinity of the wafer stage shown in FIG.

FIG. 10 is a block diagram showing a configuration of a control system according to the embodiment of the present invention.

FIG. 11 is a flowchart illustrating a first process performed by a control system according to the embodiment of the present invention.

FIG. 12 is a flowchart illustrating a second process by the control system according to the embodiment of the present invention.

FIG. 13 is a diagram showing a temperature change of a wafer holder before and after wafer suction according to the embodiment of the present invention.

FIG. 14 is a flowchart showing a third process by the control system according to the embodiment of the present invention.

FIGS. 15A and 15B are views showing the exposure order of each shot area of the wafer, wherein FIG. 15A shows the conventional exposure order, and FIG. 15B shows the exposure order of the embodiment of the present invention.

FIG. 16 is a diagram illustrating an example of a shot area for measuring a reference mark according to the embodiment of the present invention.

FIG. 17 is a diagram for describing a method of interpolating a shot magnification of a shot area in which reference mark measurement is not performed according to the embodiment of the present invention.

FIG. 18 is a flowchart illustrating a process for improving overlay accuracy by the control system according to the embodiment of the present invention.

[Description of Signs] W: Wafer (photosensitive substrate) WH: Wafer holder (substrate holder) 10: Wafer stage 22A, 55 ... Storage shelf 31, 32, 33 ... Independent chamber 38: Wafer loader system 47: Scalar robot hand, 48 ... Vertical slider body 49A, 49B Slider (transport arm) 52 Turntable 100 Exposure device 111-115 Temperature sensor 120 Control system

Claims (10)

[Claims] 1. An exposure method, comprising: measuring a temperature of a photosensitive substrate; and performing an exposure process on the photosensitive substrate after the measured temperature or a rate of change of the temperature falls within a predetermined allowable range. . 2. The temperature of a photosensitive substrate is measured, and the temperature of a substrate holder that detachably holds the photosensitive substrate is measured. The temperature difference between the measured temperature of the substrate holder and the temperature of the photosensitive substrate is determined in advance. An exposure method, comprising: performing an exposure process on the photosensitive substrate after entering a set allowable range. 3. A temperature of the photosensitive substrate being transported is measured by a substrate transport device that transports the photosensitive substrate to a transfer position with respect to the substrate holder, and the measured temperature or the rate of change of the temperature falls within a predetermined allowable range. An exposure method comprising, after entering, performing exposure processing while holding the photosensitive substrate in the substrate holder. 4. A temperature of a substrate holder which detachably holds the photosensitive substrate, and measures the temperature of the photosensitive substrate being transported by a substrate transport device which transports the photosensitive substrate and holds the photosensitive substrate on the substrate holder. An exposure method, wherein after the temperature difference between the temperature of the substrate holder and the temperature of the photosensitive substrate falls within a preset allowable range, the photosensitive substrate is held by the substrate holder to perform exposure processing. . 5. A plurality of shot areas arranged in a matrix on the photosensitive substrate by projecting an image of a pattern from an illuminated mask onto the photosensitive substrate while step-moving the photosensitive substrate. In an exposure method for transferring a pattern, the exposure processing for each of the shot areas is started from a shot area located at the approximate center of each of the shot areas, and the exposure processing is performed on a shot area surrounding the start shot area. An exposure method wherein the exposure is performed on a shot area surrounding the shot area after the exposure processing. 6. The exposure processing for each shot area, if there is an unexposed shot area that is not adjacent to the shot area immediately after the exposure processing, the exposure processing is performed on the non-adjacent shot area. The exposure method according to claim 5. 7. A method for projecting an image of a pattern from an illuminated mask onto the photosensitive substrate while step-moving the photosensitive substrate so as to transfer the pattern to a plurality of shot areas on the photosensitive substrate. In the exposure method, the expansion characteristic of the photosensitive substrate due to the energy received by the photosensitive substrate by an exposure process sequentially performed on each of the shot regions is obtained in advance, at the time of the first exposure for each shot region of the photosensitive substrate, Exposure processing is performed while correcting the image magnification for each shot area based on the expansion characteristics, and a reference mark is transferred to each shot area on the photosensitive substrate. At the time of exposure, the position of the reference mark is measured, and the amount of change in the size of each shot area is determined based on the measurement result. An exposure method, wherein an exposure process is performed while correcting an image magnification for each shot area based on the image processing. 8. A method for transferring a pattern to a plurality of shot areas on a photosensitive substrate by projecting an image of a pattern from an illuminated mask onto the photosensitive substrate while step-moving the photosensitive substrate. In the exposure method, at the time of the first exposure for each shot area of the photosensitive substrate, at least two reference marks spaced apart from each other are transferred to each shot area on the photosensitive substrate, During the second and subsequent exposures of the shot area, the positions of the reference marks are measured for a plurality of shot areas of the shot areas, and the size and the size of the shot area where the measurement of the reference mark is performed based on the measurement result Shot information that is shot information that is at least one of the amount of change in position and that does not measure the reference mark is obtained. The information is interpolated based on the shot information of the shot area in which the reference mark was measured, and these are used as correction data. Based on the correction data, at least one of the image magnification and the image position for each shot area of the photosensitive substrate is corrected. An exposure method comprising performing an exposure process while performing the exposure process. 9. The exposure method according to claim 1, wherein the exposure method is applied to an exposure apparatus for manufacturing a magnetic head. 10. An exposure apparatus for manufacturing a magnetic head, to which the exposure method according to claim 1 is applied.