JP3408057B2 - Exposure apparatus and method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus and method for a semiconductor used in a transfer step in a lithography step for manufacturing a highly integrated semiconductor circuit element, and particularly to pre-alignment and pre-alignment of a substrate such as a wafer to be exposed. Supply,
The present invention relates to an exposure apparatus and method provided with a substrate supply device for collecting.

[0002]

2. Description of the Related Art A conventional reduction projection type exposure apparatus (hereinafter,
It is called "stepper". ), As shown in FIG.
XY stage 102 driven by a known 6-axis drive table mechanism supported by 01 and XY stage 102
A top stage 103 mounted on the top stage, a reduction projection lens system 104 disposed above the top stage 103, an illumination system 105 disposed above the top stage 103, and a reticle 106 between the illumination system 105 and the reduction projection lens system 104. It has a stepper body S ₀ composed of a reticle supporting device (not shown) for supporting. The reduction projection lens system 104 is supported by the base 101 via a lens system support 104a, and the illumination system 105 is an illumination system support 105 that is integral with the lens system support 104a.
It is supported by the base 101 via a. A plurality of air mounts 108 are provided between the base 101 and the floor 107, and the base 101 is elastically supported by each air mount 108, whereby the vibration of the floor 107 is directly transmitted to the stepper body S ₀ . The stepper body S ₀ is prevented from resonating due to self-vibration, and the external vibration transmitted from the wafer transfer conveyor or the like is absorbed. The illumination light emitted from the illumination system 105 passes through the reticle 106 and the reduction projection lens system 104 and is applied to the wafer W ₀ adsorbed on the top stage 103 to expose the resist on the surface of the wafer W ₀ . Beside the stepper main body S ₀ , a substrate supply device F ₀ for automatically supplying and collecting wafers.
Are placed. As shown in FIG. 4, the substrate supply apparatus F ₀ includes a supply cassette 109 for accumulating wafers carried in from a wafer transfer conveyor (not shown) and wafers sequentially taken out from the supply cassette 109 by a robot (not shown). A pre-alignment apparatus 110 for performing pre-alignment, a carry-in hand 111 for carrying in a pre-aligned wafer into the stepper body S ₀ , exposure,
It has a carry-out hand 112 for collecting the baked wafers from the stepper body S ₀ and a collecting cassette 113 for accumulating the wafers collected by the carry-out hand 112, all of which are the base 101 of the stepper body S _0. The wafer, which is supported on an integral support base 114, is sequentially taken out by the above-mentioned robot from the wafers in the supply cassette 109 and sent to the pre-alignment device 110, and the pre-aligned wafers are transferred by the carry-in hand 111 to the stepper body S _0. A series of operations are carried out in which the wafer is carried into the wafer and exposed and baked, and the wafer that has been exposed and baked is collected from the stepper main body S ₀ by the carry-out hand 112 and stored in the collecting cassette 113.

The wafer, which has been prealigned in this way, is moved by the carry-in hand 111 to the stepper body S _0.
Then, after the final alignment with higher accuracy by the XY stage 102, the wafer is exposed as described above. The final alignment is to drive the XY stage 102 by optically detecting an alignment mark pre-printed on the wafer, which requires high accuracy to make an error of 1/100 μm a problem. For improvement, it is performed at such a high speed that a delay of 1/100 second is a problem. For this reason, the precision of the pre-alignment performed before the final alignment is also required to be about 20 μm to 60 μm, and in addition, the pre-alignment stage driving device 116 is also required to be driven at a high speed. However, as described above, the operations of the substrate supply device F ₀ and the stepper main body S ₀ are continuously repeated for each wafer. In the substrate supply device F ₀ , the wafer is taken out from the supply cassette 109 and prealigned. The step of placing the wafer on the stage 115 for pre-alignment and the step of accommodating the wafers collected from the stepper body S ₀ by the carry-out hand 112 in the collection cassette are carried out by the top stage 10 in the stepper body S ₀ .
Since the process of performing the final alignment of the wafer on 3 and the subsequent exposure and baking is almost the same time, the vibrations of the pre-alignment stage drive device 116 and the drive device such as a robot for transferring the wafer to the recovery cassette 113 are generated. There is a risk that the accuracy of final alignment and baking in the stepper main body S ₀ will be reduced by being transmitted to the base 101 via the support base 114, and various measures have been taken to prevent these vibrations.

[0004]

However, according to the technique of the above-mentioned conventional example, the vibration caused by the driving of the XY stage shakes the lens surface plate of the stepper body and the exposure cannot be performed accurately. It has come to be considered to lower the elastic support means from the target, that is, to separate the elastic support means from the lens surface plate. Even if the stepper main body is displaced by the elastic supporting means, since the XY stage is positioned from the lens surface plate by the laser interferometer, the positions of the XY stage and the lens surface plate are guaranteed, so there is no problem. However, since the substrate supply device is displaced from the lens surface plate, the wafer cannot be delivered accurately.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide an exposure apparatus capable of accurately delivering a wafer by correcting the relative positions of the substrate supply device and the lens surface plate.

[0006]

In order to achieve the above object, an exposure apparatus of the present invention comprises a lens surface plate elastically supported by elastic supporting means, and an exposure lens supported on the lens surface plate. And a pedestal supported separately from the lens stool on the elastic supporting means, an XY stage movably supported on the pedestal, and the position of the XY stage is read from the lens stool. A laser interferometer, and drive means for moving the XY stage by the output of the laser interferometer,
In an exposure apparatus having a substrate supply device that is supported on the pedestal and supplies a substrate to the XY stage, a detection unit that detects a change in relative position between the lens surface plate and the substrate supply device is provided, and the drive is performed. The means has a control means for correcting the movement amount of the XY stage based on the output of the detection means.

According to a preferred embodiment of the present invention,
The elastic supporting means includes an attitude control means for correcting the attitude of the lens surface plate based on an output of the detection means for detecting a change in relative position between the lens surface plate and the substrate supply device. To do. Further, the attitude control means detects the attitude of the lens surface plate or the X-axis based on the output of the attitude detection means that detects a change in the relative position between the lens surface plate and the floor.
It is characterized in that it has means for correcting the amount of movement of the Y stage.

In the exposure method of the present invention, a lens surface plate elastically supported by elastic supporting means, an exposure lens supported on the lens surface plate, and the lens surface plate on the elastic supporting means. A pedestal supported separately, an XY stage movably supported on the pedestal, a laser interferometer for reading the position of the XY stage from the lens surface plate,
Driving means for moving the XY stage according to the output of the laser interferometer, a substrate supply device which is supported on the pedestal and supplies a substrate to the XY stage, and a relative surface of the lens surface plate and the substrate supply device. An exposure apparatus having a detection unit that detects a change in position is used, and the movement amount when the XY stage is moved to the exposure position by the drive unit is corrected based on the output of the detection unit.

[0009]

According to the above construction, since the lens surface plate is elastically supported, it is displaced from the base surface, and the XY stage positioned by the laser interferometer is also displaced from the lens surface plate, so that the XY stage. When the substrate is transferred between the substrate supply device and the substrate supply device, the relative position of the two changes and a positional deviation occurs between the transferred substrate and the XY stage. In order to prevent the transfer deviation due to such position deviation, when the substrate is transferred, the change in the relative position between the substrate supply device and the lens surface plate is detected by the detecting means, and X
When the Y stage moves on the base, the amount of movement is corrected based on the output of the detecting means. Alternatively, it is corrected by the attitude control means of the elastic support means. Alternatively, the correction is performed based on the output of the detection unit that detects the change in the relative position between the lens surface plate and the floor.

Since the pedestal supporting the substrate supply device and the XY stage is supported separately from the lens surface plate, it is possible to prevent the vibration of the pre-alignment stage of the substrate supply device from being transmitted to the lens surface plate.

[0011]

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic elevational view showing the configuration of an exposure apparatus according to an embodiment of the present invention. The exposure apparatus of this embodiment is supported by a base 1 and is moved by a well-known 6-axis drive table mechanism which is a drive means, a top stage 3 placed on the XY stage 2, and an upper part thereof. Reduction projection lens system 4 arranged in the
And a stepper body S _{1 including} a reticle supporting device (not shown) for supporting the reticle 6 disposed between the illumination system 5 and the reduction projection lens system 4, and the reduction projection lens system 4 supports the lens system. The illumination system 5 is supported by the body (lens surface plate) 4a, and the lens system support 4 is provided via the illumination system support 5a.
supported by a. A plurality of air mounts 8 as elastic supporting means are provided between the lens system support 4a and the floor 7 or a fixed platen (not shown) on the floor 7, and the lens system support 4a is provided.
Is elastically supported by the air mount 8, together thereby preventing the transmission to the stepper body S ₁ vibration direct floor 7 prevents resonance by self-oscillation of a stepper body S _1, and the substrate conveyers Absorbs external vibration transmitted from the XY stage 2 or the like. Illumination light emitted from the illumination system 5 is reflected by the reticle 6 and the reduction projection lens system 4
After that, a wafer (not shown) which is a substrate adsorbed to the top stage 3 is irradiated with the light and the resist on the surface of the wafer is exposed.

A substrate supply device F ₁ for automatically supplying and collecting wafers is provided near the side of the stepper body S ₁ . As shown in FIG. 2, the substrate supply device F ₁ is
A supply cassette 9 for accumulating wafers carried in from a conveyor (not shown), a pre-alignment device 10 for pre-aligning the wafers sequentially taken out from the supply cassette 9, and a stepper body for pre-aligned wafers. The carry-in hand 11 for carrying in to S ₁ , the operation for collecting the exposed and baked wafers from the stepper body S _1, and the operation for successively taking out the wafers from the supply cassette 9 and carrying them into the pre-alignment apparatus 10 are alternately performed. It has a robot 12 and a cassette 13 for collecting the wafers collected by the robot 12. All of these members constituting the substrate supply device F ₁ are all included in the base 1
Supported by. The base 1 is a separate body from the lens system support 4a of the stepper body S ₁ and has a gap T ₁ (not shown) between the pre-alignment device 10 on the base 1 and the lens system support 4a. The legs of the base 1 are directly fixed to the floor 7 or a fixed plate on the floor 7. Pre-alignment device 10
Includes a pre-alignment stage 15, a pre-alignment stage driving device 16 and a position sensor 17.

Further, the pre-alignment apparatus 1 on the base 1
0 is provided with a gap sensor which is a detecting means for detecting a lateral fluctuation due to self-vibration or the like in the stepper body S ₁ and changing the width of the gap T ₁ . The gap sensor includes an X gap sensor 14a that measures a change Δx in width of the gap T _{1 in} the X axis direction and a pair of Y gap sensors 14b and 14c that measures a change Δy in width in the Y axis direction. Both Y gap sensors 14b and 14c are arranged at a predetermined interval in the X axis direction, measure the change Δy in the width of the gap T _{1 in} the Y axis direction, and measure the difference between the outputs of the Y gap sensors 14b and 14c. From this, the change Δθ in the rotation angle around the Z axis of the pre-alignment apparatus with respect to the lens system support 4a of the stepper main body S ₁ can be calculated.

The wafer taken out from the supply cassette 9 by the robot 12 and placed on the pre-alignment stage 15 is aligned at a predetermined position by the pre-alignment apparatus 10 and then by the carry-in hand 11.
It is transferred to the XY stage 2 of the stepper body S ₁ . At this time, the XY stage 2 is at the wafer transfer position where the laser interferometer 52 moves a predetermined distance from the exposure position toward the pre-alignment apparatus 10 on the base 1 by the 6-axis drive table mechanism described above. The wafer transferred from the pre-alignment apparatus 10 by the carry-in hand 11 is transferred to the X-axis.
When the Y stage 2 receives it, the X gap sensor 14a
And both Y gap sensors 14b and 14c measure the changes Δx, Δy, and Δθ in the size of the gap T ₁ between the substrate supply device F ₁ and the lens system support 4a of the stepper body S ₁ , and the measured values are the measured values. _The amount of movement when the XY stage 2 that has received the wafer is stored in the control device that is the control means of the 6-axis drive table mechanism of the XY stage 2 of 1 and returns from the wafer transfer position on the base 1 to the exposure position. To correct. That is, since the lens system support 4a is elastically supported on the floor 7 via the air mount 8 as described above, when the wafer is transferred, it is laterally moved by the self-vibration of the stepper main body S ₁ or the like. There is a tendency for fluctuations to occur and the size of the gap T ₁ to change.
_If the dimension of ₁ changes, the relative position of the XY stage at the wafer transfer position and the wafer on the pre-alignment stage 15 changes, and the wafer cannot be transferred to a predetermined position on the XY stage 2. A displacement as much as the change in the width of T ₁ occurs. Therefore, such a positional shift that is a change in the relative position is detected by the X gap sensor 14a and both Y gap sensors 14b and 14c,
The 6-axis drive table mechanism corrects the movement amount of the XY stage 2 when returning from the wafer transfer position to the exposure position, thereby preventing the wafer at the exposure position from being displaced.

When the XY stage 2 returns to the exposure position, final alignment of the wafer is performed by an alignment optical system (not shown), followed by exposure of the wafer by a known method.
Baking is performed. The exposed and baked wafer is taken out from the stepper body S ₁ by the robot 12 and stored in the collecting cassette 13. While the robot 12 stores the wafer in the recovery cassette 13, the stepper body S ₁ performs the final alignment and subsequent exposure and baking for the next wafer, and at the same time, the prealignment apparatus 10 performs the next exposure and baking. The wafer is pre-aligned.

Further, the air mount 8 is provided with the attitude control means 5
1, the amount of air supplied is changed to change the lens system support 4
The posture of a can be controlled. When the wafer is delivered, the change in the relative position between the lens surface plate and the floor is detected by the X gap sensor 14a and both Y gap sensors 14b and 14c, and the attitude control means 51 tilts the stepper body S ₁ to the correct delivery position. In addition, the attitude control means 51 detects the positional displacement between the floor 7 and the lens system support 4 a, and the mount sensor 5.
With 0, the posture of the stepper main body S ₁ is tilted to the correct delivery position. Alternatively, the position of the XY stage 2 is corrected by the detection signal of the mount sensor 50.

According to the present embodiment, the substrate supply device F ₁ is directly supported on the floor 7 and is a separate body from the lens system support 4a of the stepper body S ₁ , so that the pre-alignment device 10 of the substrate supply device F ₁ is used. The vibration caused by the driving of the robot 12 or the robot 12 is not transmitted to the stepper main body S ₁ , and therefore even if the pre-alignment apparatus 10 or the robot 12 is driven at a high speed, the final alignment or exposure of the wafer in the stepper main body S ₁ is performed. There is no risk of lowering the baking accuracy.
Further, since the XY stage 2 is also separated from the lens surface plate, the exposure due to the driving of the XY stage does not shake the lens surface plate of the stepper main body, and the exposure can be performed accurately.

[0018]

As described above, according to the present invention,
Since the relative positions of the substrate supply device and the lens surface plate can be corrected and the wafer can be transferred with high accuracy, the XY stage is lowered from the elastic supporting means for vibration isolation, that is, separated from the lens surface plate. Therefore, the exposure due to the driving of the XY stage can be performed accurately without shaking the lens surface plate of the stepper body.

[Brief description of drawings]

FIG. 1 is a schematic elevational view showing an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of the device shown in FIG.

FIG. 3 is a schematic elevational view showing a conventional exposure apparatus.

FIG. 4 is a schematic plan view of the device of FIG.

[Explanation of symbols]

S ₁ : stepper main body, F ₁ : substrate supply device, 1: platform,
2: XY stage, 3: top stage, 4: reduction projection lens system, 4a: lens system support (lens surface plate), 5:
Illumination system, 6: Reticle, 8: Air mount, 9: Supply cassette, 10: Pre-alignment device, 11: Carrying hand, 12: Robot, 13: Collection cassette, 14
a: X gap sensor, 14b, 14c: Y gap sensor, 15: pre-alignment stage, 16: pre-alignment stage drive device, 17: position sensor,
50a, 50b, 50c: mount sensor, 51: attitude control means, 52: interferometer.

Claims (5)

(57) [Claims] 1. A lens surface plate elastically supported by elastic supporting means, an exposure lens supported on the lens surface plate, and a base supported separately from the lens surface plate on the elastic supporting means. Board and XY movably supported on the base board
A stage, a laser interferometer for reading the position of the XY stage from the lens surface plate, a drive means for moving the XY stage by the output of the laser interferometer, and the XY stage supported on the platform. An exposure apparatus having a substrate supply device for supplying a substrate to a substrate, the detection device detecting a change in relative position of the lens surface plate and the substrate supply device, and the XY stage of the XY stage based on an output of the detection device. An exposure apparatus comprising: a control unit that corrects a movement amount by a drive unit. 2. The exposure apparatus according to claim 1, wherein the elastic support means has an attitude control means for correcting the attitude of the lens surface plate based on the output of the detection means. 3. An attitude detecting means for detecting a change in relative position between the lens surface plate and the floor, and an attitude correcting means for correcting the attitude of the lens surface plate based on the output of the attitude detecting means. The exposure apparatus according to claim 1, wherein: 4. A posture detecting means for detecting a change in relative position between the lens surface plate and the floor, and a movement amount correcting means for correcting the movement amount of the XY stage based on the output of the posture detecting means. The exposure apparatus according to claim 1, wherein: 5. A lens surface plate elastically supported by elastic support means, an exposure lens supported on the lens surface plate, and a base separately supported by the lens surface plate on the elastic support means. Board and XY movably supported on the base board
A stage, a laser interferometer for reading the position of the XY stage from the lens surface plate, a drive means for moving the XY stage by the output of the laser interferometer, and the XY stage supported on the platform. An exposure apparatus having a substrate supply device for supplying a substrate to the substrate, and a detection means for detecting a change in the relative position of the lens surface plate and the substrate supply device is used, and the drive means is operated by the drive means based on the output of the detection means. An exposure method which corrects a movement amount when the XY stage is moved to an exposure position.