JPH0774084A - Substrate processor - Google Patents

Abstract

PURPOSE:To perform the precise prealignment of the next substrate while a substrate processing means processes one sheet of wafer, by correcting cross marks after performing the measure for precise alignment on a carry means. CONSTITUTION:After finish of rough prealignment, in the detection precise prealignment on a carry band part 201 before delivering to an XY-stage, the cross marks 41 and 42 of a wafer W are detected by shifting the band side. Furthermore, as regards the correction drive after detection of the cross marks 41 and 42, for theta direction, they are corrected with a carrying-in band part 201, and for X- and Y-directions, they are corrected with the X- and Y-stage of an exposer body So. Accordingly, while the processing means for a substrate processes one sheet of wafer, the precise alignment of the next substrate is performed in parallel, and the throughput shortens.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus used for manufacturing semiconductor elements, and more particularly to a substrate processing apparatus such as an exposure apparatus equipped with a substrate pre-alignment for a substrate such as a wafer to be exposed. .

[0002]

2. Description of the Related Art A conventional reduction projection type exposure apparatus (hereinafter referred to as "stepper") has a base 101 as shown in FIG.
The XY stage 102 driven by a known 6-axis drive table mechanism supported on the XY stage 102, a fine movement stage 103 mounted on the XY stage 102, a reduction projection lens system 104 arranged above the XY stage 102, and a fine projection lens system 104 above it. Arranged illumination system 105, illumination system 105 and reduction projection lens system 104
A stepper body S ₀ consisting reticle supporting device (not shown) which supports the reticle 106 during the reduction projection lens system 104 is supported by the weighing table 101 via the lens system support 104a, also The illumination system 105 is an illumination 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 external vibration transmitted from a 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,
The resist on the surface of the wafer W ₀ is exposed.

A substrate supply device F ₀ for automatically supplying and recovering wafers is arranged beside the stepper body S ₀ , and the substrate supply device F ₀ is not shown as shown in FIG. A supply cassette 109 for accumulating wafers carried in from a wafer transfer conveyor or the like, and a supply cassette 10.
9, a pre-alignment apparatus 110 for pre-aligning wafers sequentially taken out by a robot (not shown), a carry-in hand 111 for carrying the pre-aligned wafers into the stepper body S ₀ , and a stepper for exposing and exposing the wafers. It has a carry-out hand 112 for collecting from the main body S ₀ and a collecting cassette 113 for accumulating the wafers collected by the carry-out hand 112, and these are all on a support base 114 which is integrated with the base 101 of the stepper main body S _0. Is supported by the supply cassette 109
The wafers therein are sequentially taken out by the robot described above and sent to the pre-alignment apparatus 110, and the pre-aligned wafers are carried into the stepper body S ₀ by the carry-in hand 111 to be exposed and baked, and the exposed and baked wafers are completed. A series of operations for collecting the sheet from the stepper body S ₀ by the carry-out hand 112 and storing it in the collecting cassette 113 are continuously performed.

The pre-alignment apparatus 110 includes a pre-alignment stage 115 for adsorbing a wafer supplied from the supply cassette 109 and a pre-alignment stage 115 which are orthogonal to each other in two axes (hereinafter referred to as "X").
Axis, Y axis ". ) Direction and a pre-alignment stage drive device 116 that rotates around an axis (hereinafter, referred to as “Z axis”) perpendicular to the two axes, and a position of the wafer attracted to the pre-alignment stage 115. A position sensor 117 for detecting As shown in FIGS. 7A and 7B, the position sensor 117 includes one X position sensor 117.
a and a pair of Y position sensors 117b and 117c arranged at a predetermined interval in the X-axis direction. First, while rotating the pre-alignment stage 115, the orientation flat of the wafer W ₁ from the output of the X position sensor 117a ( The rotation direction position of the notch C ₁ provided on the outer peripheral edge is detected, and the orientation flat C ₁ is detected by both Y position sensors 117.
After the rotation of the pre-alignment stage 115 is stopped at a position parallel to the b and 117c (shown in (b) of FIG. 7), the pre-alignment stage 115 is moved in the Y-axis direction to move both the Y position sensors 117b and 117c. The position adjustment in the Y-axis direction is performed based on the output of the above, and then the pre-alignment stage 115 is moved in the X-axis direction to perform the position adjustment in the X-axis direction by the X position sensor 117a.

In this way, the wafer, which has been pre-aligned, 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 a high precision enough 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.

[0007]

However, in the pre-alignment method as in the above-mentioned conventional example, 20 to 3 is used.
Since only 0 μm accuracy can be achieved, it does not enter the detection necessary area (about 5 μm) for final high-precision alignment. Therefore, the two pre-alignment marks provided in the wafer are optically detected again on the XY stage 102 to perform precision pre-alignment. In this way, since the alignment mark measurement and driving of the precision pre-alignment are performed after mounting on the XY stage, the productivity (throughput) is disadvantageous by that amount of time, and
Not only is the mechanism complicated, such as by providing a coarse θ rotation mechanism on the XY table, but also the weight is increased.
The step time of 2 becomes long, and the throughput is inevitably reduced.

An object of the present invention is to improve the throughput in a substrate processing apparatus in view of the above problems of the prior art.

[0009]

To achieve this object, in the present invention, means for holding a substrate, means for driving the substrate holding means to perform precise alignment of the substrate,
Substrate processing means for performing a predetermined process on the substrate held by the substrate holding means and subjected to precise alignment, substrate driving means for holding and moving the substrate, and an end portion of the substrate held by the substrate driving means And a control for performing relatively rough positioning of the substrate by controlling the operation of the substrate driving means so that the output value of the sensor is within a predetermined tolerance range with respect to a predetermined target value. In a substrate processing apparatus including a pre-alignment unit including a unit, and a transfer unit that holds the substrate on which the rough positioning is performed and transfers the substrate onto the substrate holding unit,
A mark detecting means for detecting two or more marks on the substrate while the carrying means holds the roughly positioned substrate, and a reference for performing relatively precise pre-alignment based on the detection result. And a means for obtaining the amount of deviation in the θ direction, which is the rotational direction about the Z axis and the Z axis with respect to the position.

The transfer means has, for example, means for correcting the deviation in the θ direction while holding the substrate, and the substrate processing apparatus further includes the transfer means for receiving the substrate on the substrate holding means. There is provided means for correcting the displacement in the X and Y directions by drivingly controlling the substrate holding means at the time of transfer or by using an offset value when the substrate holding means is driven. Further, the carrying means may have means for correcting the displacement in the X, Y and θ directions while holding the substrate. Alternatively, the substrate holding means may be drive-controlled to have a means for correcting the deviation in the X, Y and θ directions.

The mark detecting means, for example, drives and controls the conveying means to sequentially position two or more marks held on the substrate at predetermined detection positions and detect the marks. . Further, the mark detecting means has two detection systems, and by doing so, it is possible to detect marks located at two different points at the same time. It may be arranged so as to be located at a predetermined detection position and detect two marks on the substrate at the same time. Furthermore, it is preferable that the distance between the two detection systems can be adjusted. Alternatively, the mark detecting means may drive-control the conveying means to stop the conveying means at a predetermined detection position and sequentially detect the marks at two or more points on the substrate held by the mark by moving the marks. . It is preferable that the predetermined detection position is located on a transportation path of the transportation means to the substrate holding means.

The substrate processing means is, for example, an exposure means for forming a semiconductor element on the substrate or an inspection means for inspecting the substrate.

[0013]

According to this structure, with respect to the substrate on which the rough pre-alignment has been performed, the deviation is further detected on the carrying means during the carrying to the substrate processing means, so that more precise pre-alignment can be performed. Therefore, while the substrate processing means is processing one wafer, the precision pre-alignment of the next substrate is performed in parallel, and the throughput is greatly reduced. Further, when the substrate is transferred onto the substrate holding means in the substrate processing means, the precise pre-alignment is substantially completed, and the pre-alignment θ mechanism in the substrate processing means becomes unnecessary.
Therefore, in the substrate processing means, the 6-axis table (X
It is possible to provide a substrate processing apparatus having a high precision and a high productivity while having a simple and lightweight mechanism such as a Y stage).

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a main part of an exposure apparatus according to an embodiment of the present invention. FIG. 2 is a schematic plan view showing a substrate supply device portion of the device of FIG. FIG. 3 is a schematic elevation view of the rough pre-alignment section.

In FIG. 1, reference numeral 9 is an original plate (reticle) having a pattern to be exposed and transferred, 11 is a wafer chuck for holding an original plate on which a resist as an exposed object is applied at an exposure position, and 8 is an exposure illumination system (not shown). A projection lens for projecting and exposing a pattern on the surface of the reticle 9 illuminated by the light flux from the drawing) onto the wafer W mounted on the wafer chuck 11. A semiconductor element is manufactured by processing the exposed resist on the surface of the wafer W through a known developing process.

1X is a laser interferometer for measuring the length in the X direction, 1Y is a laser interferometer for measuring the length in the Y direction, and 2Yθ
Is a laser interferometer for performing yawing measurement.
Reference numeral 3 denotes a mirror (measurement surface XY) measured by these laser interference systems, and a θ rotation table (fine movement stage) 5
It is placed on top.

The fine movement stage 5 is installed on the XY table (X, Y stage) 4. Reference numeral 6 is a rotary drive mechanism for rotating the θ rotary table 5 using a piezoelectric element, and 7a, 7a.
Reference numeral b is a drive unit (motor) that drives the XY table 4 in the X and Y directions, respectively. Although not shown here, the θ rotary table 5 also has a built-in drive system for driving the θ rotary table 5 in the Z direction and the tilt direction.

Reference numeral 10 is a control box including a drive circuit and the like. Detection marks (not shown) are provided on the rotary table 5 and the XY table 4. 16 is an off-axis microscope.

As shown in FIG. 2, a substrate supply device F ₀ for automatically supplying and recovering wafers is arranged near the side of the stepper body S ₀ , and the substrate supply device F ₀ is for wafer transfer (not shown). A supply cassette 109 for accumulating wafers carried in from a conveyor or the like, and a rough pre-alignment device 11 for performing pre-alignment of wafers sequentially taken out from the supply cassette 109 by a robot (not shown).
It has a carry-in hand section 201 for carrying in ₀ and the wafer after rough pre-alignment into the stepper main body S ₀ . The carry-in hand unit 201 includes a linear guide 204, a linear and vertical drive unit 205, and as shown in FIG. 3, a wafer suction hand 203 rotatably held and a rotary drive unit 202 thereof. The step and exposure are repeated by the XY table 4 and the θ rotation table 5 which constitute the wafer stage system, and the wafer after the exposure is recovered by the recovery hand 112.

The pre-alignment apparatus 110 has a pre-alignment stage 11 on which a wafer taken out of the supply cassette 109 is placed, as in the case of the conventional example.
5, a pre-alignment stage drive unit 116 for moving the unit around the X-axis, Y-axis direction and Z-axis, and a position sensor 117 for detecting the orientation flat of the wafer.

The wafer W taken out of the supply cassette 109 and placed on the pre-alignment stage 115.
After being aligned at a predetermined position by the pre-alignment device 110, the carry-in hand 203 (the carry-in hand unit 2
It is adsorbed and held by 01). After that, as shown in FIG. 4, the cross mark 41 on the wafer W is moved along the linear guide 204 until it comes under the off-axis microscope 16 (position in FIG. 4), and then the wafer surface is moved to the off-axis microscope 16. Vertical drive unit 205 until it is located on the focus surface of 16
Is raised by. Instead of this, the focus surface of the off-axis microscope 16 may be adjusted in advance to the wafer passage position, or a focus system may be provided in the off-axis microscope 16 to operate the off-axis microscope 16 or the wafer to focus. .

At this position, the cross mark 41 for TV image measurement provided on the wafer is detected, and the deviation from the reference position is measured. Similarly, the wafer is further moved along the linear guide 204 to the position where the other cross mark 42 on the wafer is below the off-axis microscope 16 (the position in FIG. 4), and the cross mark 42 is moved by the off-axis microscope. To detect. The error of the wafer position with respect to the reference position in the X, Y and θ directions is calculated from the position information of the two points of the cross marks 41 and 42, and the rotation drive unit 20 in the θ rotation direction.
2, the suction hand 203 is rotated by a predetermined amount to correct the error.

After that, the hand section 201 is moved to the wafer supply position (the position shown in FIG. 4), and when the wafer W is transferred to the wafer chuck 11, the XY stage 4 side is corrected and driven for X and Y transfer.

Here, a certain amount of deviation of the wafer W from the X and Y reference positions, and the Y axis (or X) of the stepper body.
A certain amount of angular error of the axis (Y axis) of the linear guide 204 with respect to the axis is input in advance as an offset.

Further, the delivery deviation that occurs when the wafer is delivered to the wafer stage and the remaining error of the rotation error by the rotation mechanism 202 are the errors in the detection area at the time of the final alignment. Therefore, the delivered wafer W is
At the time of final alignment, final alignment is performed by an alignment optical system (not shown) and X, Y and fine θ mechanisms that drive the XY stage 4 and the θ rotary table 5, and the wafer is exposed by a known method. During the final alignment measurement and the step-and-repeat repeated exposure, rough pre-alignment and precise pre-alignment measurement of the next wafer and θ drive are performed.

The exposed wafer is moved to the collecting position by the wafer stage (4, 5), and the collecting hand 1
After the wafer is recovered by 12, the XY stage 4 performs the X and Y correction movement on the next wafer based on the detection result of the off-axis microscope 16, and then the loading hand unit 2
Delivery by 01 is performed.

In this embodiment, after the rough pre-alignment is completed, the hand side is moved to detect the precise pre-alignment on the carry-in hand section 201 before the transfer to the XY stage 4, and the marks 41, 41 on the wafer W are moved. Although 42 is detected, the marks may be detected simultaneously with the off-axis microscope 16 having two eyes as shown in FIG. At this time, the mark 4 on the wafer
If the span of the microscope 16 can be adjusted according to the positions 1, 42, various layouts can be supported.

When the off-axis microscope 16 to be detected is a monocular, the off-axis microscope 16 side may be driven to detect the marks 41 and 42.

Further, regarding the correction drive after detecting the marks 41, 42, the θ direction is corrected by the carry-in hand unit 201, and the X, Y directions are corrected by the XY stage 4 of the exposure apparatus main body S ₀ . The X, Y, and θ all directions may be corrected by the carry-in hand unit 201 or may be corrected on the exposure apparatus main body S ₀ side.

[0030]

As described above, according to the present invention, since the precise pre-alignment measurement is carried out on the transfer means and the correction is further performed, the substrate processing means processes one wafer. Since the pre-alignment of the next substrate can be performed in parallel while it is in the middle, the throughput can be significantly reduced.

Further, the θ driving mechanism for precise pre-alignment is not required in the substrate processing means, and it is sufficient to provide only the final fine alignment θ mechanism for rotating the mirror surface to which the laser length measuring light is applied, so that the structure is simplified. Therefore, it is possible to improve the accuracy, shorten the step time, etc., and significantly improve the productivity.

[Brief description of drawings]

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

FIG. 2 is a schematic plan view showing a substrate supply device portion of the device of FIG.

FIG. 3 is a schematic elevational view of a rough pre-alignment unit of the apparatus shown in FIG.

4 is a schematic plan view showing a state of precision pre-alignment measurement in the apparatus of FIG.

FIG. 5 is a schematic elevational view showing an exposure apparatus according to a conventional example.

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

FIG. 7 is a diagram for explaining the position sensor of the pre-alignment apparatus in the apparatus of FIGS. 1 and 5, and is an explanatory diagram showing a state before detecting the orientation flat of the wafer and a state in which the orientation flat is detected.

FIG. 8 is a schematic plan view showing an exposure apparatus according to another embodiment of the present invention.

[Explanation of symbols]

S ₀ : Stepper body, F ₀ : Substrate supply device, 101: Hens surface plate, 1X, 1Y, 2Yθ: Laser interferometer, 3: Laser length reference mirror, 4, 102: XY stage,
5, 103: fine movement stage, 6: θ fine movement actuator, 7a, 7b: XY drive unit, 8, 104: lens,
9, 106: reticle, 10: control unit, W, W ₀ : wafer, 105: illumination system, 107: floor, 16: off-axis microscope, 108: mount, 109: supply cassette,
110: rough pre-alignment device, 111: carry-in hand, 112: carry-out hand, 113: collection cassette, 1
14: transport system support, 115: pre-alignment stage, 116: pre-alignment drive device, 117 (a,
b, c): position sensor, 201: carry-in hand section,
202: suction hand rotation drive unit, 203: wafer suction hand, 204: linear guide, 205: linear and vertical drive unit.

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 21/68 G

Claims (11)

[Claims] 1. A means for holding a substrate, a means for driving the substrate holding means to perform a precise alignment of the substrate, and a predetermined treatment for the substrate held by the substrate holding means and subjected to the precise alignment. Substrate processing means for performing the above, a substrate driving means for holding and moving the substrate, a sensor for non-contact detection of the edge of the substrate held by the substrate driving means, and an output value of this sensor is a predetermined target value. A pre-alignment means including a control means for controlling the operation of the substrate driving means so that the substrate is relatively coarsely positioned within a predetermined tolerance range with respect to In a substrate processing apparatus comprising a transfer means for transferring the substrate onto the substrate holding means, the transfer means holds the roughly positioned substrate on the substrate. Mark detection means for detecting marks at or above points, and θ direction, which is a rotation direction about the X and Y directions and the Z axis with respect to the reference position, for performing relatively precise prealignment based on the detection result. And a means for obtaining a deviation amount of the substrate processing apparatus. 2. The transfer means has means for correcting the deviation in the θ direction while holding the substrate, and the substrate processing apparatus further comprises the transfer means for receiving the substrate on the substrate holding means. 2. The substrate according to claim 1, further comprising means for correcting the displacement in the X and Y directions by controlling the driving of the substrate holding means at the time of transfer or by using an offset value when the substrate holding means is driven. Processing equipment. 3. The substrate processing apparatus according to claim 1, wherein the transfer unit has a unit that corrects the deviation in the X, Y and θ directions while holding the substrate. 4. The substrate processing apparatus according to claim 1, further comprising means for driving and controlling the substrate holding means to correct the deviation in the X, Y and θ directions. 5. The mark detecting means is for driving and controlling the conveying means to sequentially position two or more marks on the substrate held by the conveying means at predetermined detection positions and detect the marks. The substrate processing apparatus according to claim 1, wherein: 6. The mark detecting means has two detection systems, whereby it is possible to detect marks located at two different points at the same time, and the drive means is driven and held. 2. The substrate processing apparatus according to claim 1, wherein the substrate is positioned at a predetermined detection position, and two marks on the substrate are detected at the same time. 7. The substrate processing apparatus according to claim 6, wherein the distance between the two detection systems is adjustable. 8. The mark detecting means drives and controls the conveying means to stop at a predetermined detection position, and the self-moving marks sequentially detect the two or more marks on the substrate held thereby. The substrate processing apparatus according to claim 1, wherein the substrate processing apparatus is provided. 9. The substrate processing apparatus according to claim 6, wherein the predetermined detection position is located on a transportation path of the transportation means to the substrate holding means. 10. The substrate processing apparatus according to claim 1, wherein the substrate processing means is an exposure means for forming a semiconductor element on the substrate. 11. The substrate processing apparatus according to claim 1, wherein the substrate processing unit is an inspection unit that inspects the substrate.