JPH0674966B2 - Positioning device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a device for recording or displaying information directly on an object, a device for reading information directly from an object, or a first device.
For aligning information in a two-dimensional or three-dimensional space in a device for transferring or displaying information on an object to a second object, and particularly applied to a semiconductor manufacturing device such as a step-and-repeat type X-ray aligner Alignment device

[Prior Art] Conventionally, this type of alignment apparatus includes a detection unit that measures the position of an object to be aligned, the amount of deviation of the object to a desired position, and the drive unit of the object. According to the measurement result, the driving means moves the object to perform the alignment.

In this case, the position of the object is represented in the coordinate system of the detection means which measures it, while the drive amount is represented in the coordinate system of the drive means. The detecting means and the driving means are arranged so that the coordinate system of the detecting means and the coordinate system of the driving means have a predetermined relationship. Therefore, the alignment of the object is calculated by calculating the driving amount of the driving unit from the displacement amount measured by the detecting unit using the relationship between these coordinate systems which is clear in advance, and moving the object by driving that amount. I was doing.

However, in actuality, when arranging the detection means and the driving means when assembling the device, there is a positioning error in these means, and due to fluctuations in the external environment such as vibration and heat,
The predetermined relationship between the detecting means and the driving means changes because of the displacement of the arrangement positions of the detecting means and the driving means. At this time, since the drive amount is calculated according to the value measured by the detection means and the drive means is driven, the predetermined relationship between the coordinate system of the detection means and the coordinate system of the drive means which has been assumed in advance has changed. However, there is a drawback that the alignment of the objects becomes poor. This is a serious problem particularly in an X-ray aligner or the like which requires high alignment accuracy.

Furthermore, in a step-and-repeat type semiconductor manufacturing exposure apparatus, a so-called stepper, a wafer is divided into a plurality of areas (shots) when exposed (pattern transfer),
Each shot is exposed. At this time, the positioning accuracy between shots is required to be 0.1 μm based on a mask (reticle) having a pattern. In order to maintain such high positioning accuracy, the wafer is moved while monitoring the position of the wafer during the step movement. But,
Even in such a case, if there is a change from the above-mentioned predetermined positional relationship between the mask or the position detecting device for alignment and the position detecting device for monitoring, it is possible to maintain high positioning accuracy. It is impossible.

[Object of the Invention] In view of the above-mentioned problems of the conventional type, an object of the present invention is to apply the present invention to a semiconductor manufacturing apparatus such as a step-and-repeat type X-ray aligner or the like to align an object such as a wafer with a predetermined position. The purpose is to enable highly accurate and efficient alignment without being affected by changes in the environment and the like. Further, the present invention is
Alignment that enables the parts of the independently configured alignment device to be related to each other during alignment, and does not require high precision in mounting parts when manufacturing the device The purpose is to provide a device.

[Description of Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the arrangement of an alignment apparatus according to an embodiment of the present invention. The apparatus shown in the figure is a positioning apparatus applied to a step-and-repeat type proximity X-ray aligner or the like.

In the figure, 1 is a fixed object, a mask made of glass or the like that transmits light, 2 is a wafer that reflects light, and the wafer is aligned with the mask 1 in a predetermined positional relationship, Reference numerals 3 and 4 are first detection devices for detecting relative positional deviation between the mask 1 and the wafer 2. The first detection device is, for example, an alignment error (X, Y, θ) detection device disclosed in Japanese Patent Laid-Open No. 59-99721. Further, as a detection device using a television (TV), the device disclosed in JP-A-59-100527 can also be used. Reference numerals 5 and 6 are driving devices for moving the wafer 2 in two directions in the plane (XY plane), and 7 is the wafer 2
Is a driving device for rotating the in-plane, 8 is a CPU for controlling the whole alignment operation, 9 is a memory such as RAM, ROM, 10 is a keyboard, 11 is a computing device 8 and detecting devices 3 and 4 , 12 is an interface circuit between the arithmetic unit 8 and the driving units 5, 6 and 7, and 13 is a wafer holder which holds the wafer 2 and moves in the XY plane.
Further, 20, 21, 22 are second detection devices for detecting the position of the wafer 2, and 23 is an interface circuit between the arithmetic unit (CPU) 8 and the detection devices 20, 21, 22.

The apparatus of this embodiment is an apparatus for transferring or displaying the pattern on the mask 1 onto the wafer 2, and the first detecting device 3 using the alignment marks provided at each of two positions on the mask 1 and the wafer 2. , 4 measure the displacement amount (X ₁ , Y ₁ ) and (X ₂ , Y ₂ ) in the two-dimensional direction at each location, and from this, the displacement amount in the X direction X = (X ₁ + X ₂ ) / 2 …… (1) Y direction deviation amount Y = (Y ₁ + Y ₂ ) / 2 …… (2) θ direction deviation amount θ = (Y ₁ −Y ₂ ) / D D is a constant …… (3) Is a positioning device for moving the wafer 2 by driving the driving devices 5, 6 and 7 based on each value. After this alignment, transfer or display is performed, and the second
While the position of the wafer 2 is monitored by the detection devices 20, 21, and 22 of FIG.
It is a device that repeatedly transfers or displays while changing the place.

Now, when the location measured by the detection devices 3 and 4 and the location when driven by the drive devices 5, 6 and 7 have a predetermined position or a predetermined positional relationship, that is, the coordinate system (X, Y, θ) and the coordinate system (X ′, Y ′,
When θ ′) has a predetermined relationship, the following relationship holds.

Here, x, y, θ represent the amount of deviation of the wafer 2 from the desired position in the coordinate system of the first detection devices 3 and 4. k _{11 to} k ₃₃ are values relating the detection devices 3 and 4 and the drive devices 5, 6 and 7, that is, the coordinate system (X, Y, θ) in the detection device and the coordinate system (X ′, Y ′, in the drive device). θ ′), and when both are in a predetermined position or in a predetermined positional relationship, the values of k _{11 to} k ₃₃ are uniquely determined. Further, a, b, and c are driving devices 5, 6 and 7 for aligning the wafer 2, respectively.
Is a coordinate system of the driving device.

From this relational expression (4), the driving amount of the driving devices 5, 6, 7 when the wafer 2 is moved to a predetermined position is obtained from the amount measured and calculated by the detecting devices 3, 4, and the position of the wafer 2 is calculated. Matching is possible.

However, in reality, in a step-and-peat type semiconductor manufacturing apparatus or the like, the wafer 2 is moved. There is a positioning error of the detection device 3, the detection device 4, the driving device 5, and the driving device 6 when assembling the device. Due to changes in the positions of the detection device 3 and the detection device 4, the drive device 5, and the drive device 6 due to changes in the external environment such as heat, the predetermined positions between the detection devices 3 and 4 and the drive devices 5 and 6 are determined. Relationship changes. That is, at this time, since the predetermined relationship between the coordinate system in the detection device and the coordinate system in the drive device changes, the relationship between the displacement amount measured by the detection devices 3 and 4 and the amount driven by the drive devices 5 and 6 is shown ( 4) k ₁₁ to k in the formula
The value of ₃₃ changes and formula (4) no longer holds. For this reason, if the wafer 2 is moved according to the equation (4), there is a problem that the alignment becomes defective.

On the other hand, in the step-and-repeat type semiconductor manufacturing exposure apparatus so-called stepper to which the present invention is applied,
As described above, the positioning accuracy between shots is required to be 0.1 μm based on the mask 1 having a pattern. Such high positioning accuracy cannot be realized if there is a change from the predetermined positional relationship between the mask 1 or the detection devices 3, 4 and the detection devices 20, 21, 22.

The alignment device of the present invention solves the above problems.

The principle of the alignment of the present invention will be described with reference to the above embodiments.

In this embodiment, first, the relationship between the coordinate system of the first detecting means and the coordinate system of the driving means is obtained before performing the alignment, and the relational expression is used to enable highly accurate alignment. That is, k ₁₁ to k ₃₃ in the above relational expression (4) are obtained before alignment, and this value is used for alignment.

From equation (4), if this is transformed, However, The inverse matrix of And

That is, Is. From this, l _{11 to} l ₃₃ are one of a, b, and c
And other values are set to 0, for example, a = 1 and b = c = 0, and x, y, θ are obtained. In the above example, l ₁₁ = x, l
₂₁ = y, l ₃₁ = θ. In the following process, l ₁₁ to l ₃₃ are obtained based on this principle.

In the embodiment shown in FIG. 1, the two first detection devices measure deviations in three directions (XYθ directions), and the driving device is
The case where three units are provided for the XYθ directions is shown, but generally n
When the number of detecting devices and the number of driving devices are n, the one corresponding to the equation (1) is Then, k _{11 to} knn can be obtained by the same method as described above, and the alignment can be performed. Where (x ₁ , x
₂ ..., xn) is the amount of displacement of the object in the n-dimensional coordinate system measured by n detectors, and (a ₁ , a ₂ ..., an) is the drive of the n driving devices in the n-dimensional coordinate system. Is the amount.

On the other hand, between the drive amounts a, b, c and the movement amount of the wafer 2 measured and calculated by the second detection devices 20, 21, 22, that is, the deviation amounts Δx, Δy, Δθ of the wafer 2 from the desired position. Is Holds. Here, L _{11 to} L ₃₃ are values that relate the detecting devices 20, 21, 22 and the driving devices 5, 6, 7 to each other, and indicate the relationship between the coordinate system of the second detecting device and the coordinate system of the driving device. ing.

According to equation (4) and equation (8) here, given that, Therefore, the relationship connecting the measurement values of the detection devices 3 and 4 and the measurement values of the detection devices 20, 21, and 22 is obtained. In fact, with L _{11 to} L ₃₃
From k _{11 to} k ₃₃ , this relationship is shown using Eq. (10) M _{11 to} M ₃₃
The value of can be obtained.

When the wafer 2 is moved while being monitored by the detection devices 20, 21, and 22, the following is performed. For example, the wafer 2 x _1, y _1, when it is desired to move theta _1, the amount [Delta] x ₁ is detected by the detector 20, 21 and 22, [Delta] y _1, the Delta] z ₁ The wafer 2 may be moved so that In this way, even when the drive devices 5, 6, and 7 are moved over a long distance, the error that occurs at that time can be eliminated.

The operation of the apparatus shown in FIG. 1 will be described below with reference to the flowchart shown in FIG.

In the figure, Step S21 obtains the l ₁₁ to l ₃₃ and (8) L ₁₁ ~L ₃₃ in the formula in equation (5) the process, step S22
Is a process for aligning the mask 1 and the wafer 2, step S2
3 is a process for obtaining the amount of movement detected by the detectors 20, 21, 22 when the wafer 2 is moved, and step S24 is a process for moving the wafer 2 to a predetermined position.

The positioning operation described below is performed by the CPU (arithmetic unit).
All are controlled and calculated by 8. The details of these processes will be described below.

In FIG. 2, in step S21, first, a predetermined alignment mark displacement amount (X ₁ ,
Y ₁₎ and takes in (X _2, Y _2), in CPU 8 (1) to Expression
Calculate each deviation amount using the formula (3) and calculate these values as x ₁ , y
_It is stored in the memory 9 as ₁ and θ ₁ . The alignment mark is attached to the mask 1 and the wafer 2 in advance. Further, the values Δx ₁₁ , Δy ₁₁ , and Δz ₁₁ measured by the detection devices 20, 21 and 22 are stored in the memory 9 via the interface circuit 23.

Next, the driving device 5 is driven by a unit amount while the driving devices 6 and 7 are stopped. It should be noted that the unit amount here may be a predetermined amount, and may be any amount that can give a drive amount to the drive means with this amount as a reference.

At this time, the shift amounts x ₂ , y ₂ and θ ₂ of the wafer 2 with respect to the mask 1 are calculated from the shift amounts (X ₁ , Y ₁ ) and (X ₂ , Y ₂ ) of the alignment marks measured by the detection devices 3 and 4. Find in memory 9
Remember. Further, x ₁ , y ₁ , θ ₁ and x ₂ , y ₂ , in the memory 9
The difference of θ ₂ is calculated by using the CPU 8 as l ₁₁ = x ₂ −x ₁ , l ₂₁ = y ₂ −y ₁ , l ₃₁ = θ ₂ −θ ₁・ ・ ・ (1
3) is calculated and stored in the memory 9. In addition, the detection device 20,21
And the values measured at 22 and 22, Δx ₁₂ , Δy ₁₂ , Δz ₁₂ ,
It is stored in the memory 9. And the previously measured Δx ₁₁ , Δy ₁₁ ,
The CPU 8 calculates the difference from Δz ₁₁ to obtain L ₁₁ = Δx ₁₂ −Δx ₁₁ , L ₂₁ = Δy ₁₂ −Δy ₁₁ , L ₃₁ = ΔZ ₁₂ −ΔZ ₁₁ (14) and the memory 9 Remember.

Next, with the driving devices 5 and 7 stopped, the driving device 6 is driven by a unit amount, and the same process as above is performed to obtain the shift amounts x ₃ , y ₃ , θ ₃ .
l ₁₂ , l ₂₂ , l ₃₂ are calculated and stored in the memory 9. Then, the values measured by the detection devices 20, 21 and 22 and Δx ₁₃ , Δy ₁₃ , Δz ₁₃ , L ₁₂ , L ₂₂ and L ₃₂ obtained by similar processing are stored in the memory 9.

Next, with the driving devices 5 and 6 stopped, the driving device 7 is driven by a unit amount, and the same process as above is performed to obtain the shift amounts x ₄ , y ₄ , θ ₄ .
l ₁₃ , l ₂₃ , l ₃₃ are calculated and stored in the memory 9. Then, the values measured by the detection devices 20, 21, and 22 and Δx ₁₄ , Δy ₁₄ , Δz ₁₄ , L ₁₃ , L ₂₃ , and L ₃₃ obtained by similar processing are stored in the memory 9.

Through the above processing, l ₁₁ to l ₃₃ and L _{11 to} L ₃₃ were obtained.

In step S22, the mask 1 and the wafer 2 are aligned. To do this, first, using l ₁₁ to l ₃₃ stored in the memory 9, the arithmetic unit (CPU) 8 calculates k ₁₁ to k ₃₃ from the equation (6).
Ask for. This is stored in the memory 9. Next, the last measured displacement amount x ₄ , y ₄ , θ ₄ is the displacement amount x, y, θ at the present time. Therefore, using this value and k ₁₁ to k ₃₃ , from the equation (4), Amount of driving device 5,6,7 for aligning wafer 2
Find a, b, c. Furthermore, drive devices 5, 6, 7 are controlled by CPU8.
The wafer 2 is moved to a predetermined position by driving a, b, and c. As a result, alignment is performed.

In step 23, L ₁₁ ~L ₃₃ obtained in step S21, using k ₁₁ to k ₃₃ obtained in step S22, the arithmetic unit 10, Ask for. Where x, y and θ are the wafer 2 seen from the mask 1.
Is the amount to move. As a result, the amounts Δx ₁ , Δy ₁ and Δz ₁ of moving the wafer 2 viewed from the detection devices 20, 21 and 22 are obtained.

In step S24, the drive devices 5, 6 and 7 are used under the control of the CPU 8, and the detection devices 20, 21 and 22 are Δx ₁ + Δx ₁₄ , Δy ₁ + Δy.
_The wafer 2 is moved so as to measure a value of ₁₄ , Δz ₁ + Δz ₁₄ . As a result, the wafer 2 is aligned at a predetermined position.

FIG. 3 shows the configuration of the alignment position obtained by partially modifying the embodiment of FIG. In the apparatus of FIG. 3, the same or common parts as those of the apparatus shown in FIG. 1 are designated by the same reference numerals.

Unlike the apparatus shown in FIG. 1, the apparatus shown in the figure aligns the wafer 2 in an apparatus which directly records or displays information on the wafer 2 without the mask 1 or reads information from the wafer 2. . Then, in this case, the wafer 2 is located at a predetermined position in space or the detection devices 3 and 4.
Are aligned in a predetermined relative positional relationship with respect to. This apparatus is a positioning apparatus applied in an exposure apparatus such as electron beam exposure.

In this modification, the alignment can be performed by the same operation as that of the above-described embodiment except that the detection devices 3 and 4 directly detect the position of the wafer 2.

These embodiments and modifications can be applied to a step-and-repeat type semiconductor manufacturing apparatus or the like, and a value relating the coordinate system can be obtained at each alignment stage. Also, during the first alignment operation of the day, the first operation of one lot, or the first operation after a large change in the environment, etc., the measured values of the detection device and the drive device It is also possible to obtain a value that correlates with the value to be moved.

For example, FIG. 4 is a flowchart showing an example of the alignment operation in the above-described embodiment and modification.

In the figure, in step S31, at the time of the first alignment operation of the day as described above, at the time of the first operation of one lot, or at the time of the first operation after a large change in environment etc.
An instruction from the keyboard 10 or a sensor for monitoring environmental changes and the like is given to the CPU 8 so as to obtain a related value at the time when a predetermined event occurs. Then, step S32
When alignment is started in step S33, first, in step S33, it is determined whether or not it is the time point instructed in step S31, that is, whether or not it is necessary to obtain a correlation value. If it is necessary, in step S34, the related value is obtained in the same manner as in steps S11 and S12 in FIG. 2 described above. Next, the value obtained in step S35 is stored in a predetermined location in the memory 9 so that it can be used in the subsequent processing. Memory 9 first
If this value is stored therein, the stored value will be corrected to the latest value.

In step S36, the associated value is read from the memory 9. Then, in steps S37 and S38, similarly to steps S13 and S14 in FIG. 2, the drive amounts of the drive devices 5 and 6 for moving are obtained, and the drive devices 5 and 6 are driven by the amount to drive the wafer 2 Align.

If it is determined in step S33 that it is not necessary to obtain the value to be associated, the alignment is performed in steps S36 to S38.

The above process is repeated as necessary when the wafer 2 is changed.

[Effects of the Invention] As described above, according to the present invention, a positioning device for applying an object such as a wafer to a predetermined position is applied to a semiconductor manufacturing apparatus such as a step-and-repeat type X-ray aligner. The drive means is driven by a predetermined amount to measure the amount of movement of the object, and the relationship between the coordinate system of the first detection means and the coordinate system of the drive means and the coordinate system of the first detection means and the second coordinate are measured from the measurement results. Since the relationship with the coordinate system in the detection means is calculated, and the relationship is used to align the object to a desired position and move in steps, the following effects are obtained.

Even if there is a change in the predetermined positional relationship between the detecting means and the driving means, this positional relationship is calculated as necessary, so that highly accurate alignment is always possible.

The second for monitoring the position of the object when moving in steps
With respect to the detecting means, the positional relationship between the detecting means and the first detecting means is obtained as necessary, so that high positioning accuracy can be maintained even during step movement.

Not affected by fluctuations due to external environment such as vibration and heat.

It enables efficient and especially time-efficient alignment.

Facilitates the manufacture of the device. In particular, a high placement position (alignment) accuracy is not required when attaching each part to the apparatus body.

It is possible to make mutual relations between the parts that are configured independently. Thus, the effects (1) to (3) can be obtained even for an independently configured device.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an alignment apparatus according to an embodiment of the present invention, FIG. 2 is a flow chart for explaining a flow of alignment processing of the apparatus of FIG. 1, and FIG. FIG. 4 is a configuration diagram of a positioning device which is a modified example of the device shown in FIG. 4, and FIG. 4 is a flowchart showing an example of the positioning operation. 1: Mask, 2: Wafer, 3,4: First detection device, 5,6,7: Drive device, 8: Arithmetic device (CPU), 9: Memory, 10: Keyboard, 20,21, 22: First 2 detectors.

Claims (5)

[Claims] 1. A first detecting means and a second detecting means for measuring the position of an object, a driving means for moving the object, and a predetermined amount of driving of the driving means before alignment, in which case Control means for measuring the amount of movement of the object by the first detection means and the second detection means, the relationship between the coordinate system in the first detection means and the coordinate system in the drive means based on the measurement result, and Using the calculating means for calculating the relationship between the coordinate system of the first detecting means and the coordinate system of the second detecting means, and the relationship between the coordinate system of the first detecting means and the coordinate system of the driving means. And a movement control means for moving the object using the relationship between the coordinate system of the first detection means and the coordinate system of the second detection means. Alignment apparatus according to claim. 2. The object is a semiconductor wafer for projecting a pattern drawn on a mask, and the first detecting means measures a relative positional relationship between the mask and the semiconductor wafer. Alignment device according to item 1 of the above. 3. The first object is a semiconductor wafer, and the first object is a semiconductor wafer.
The detection means for measuring the relative position of the semiconductor wafer with respect to a predetermined reference position.
The alignment device according to the item. 4. The alignment apparatus according to claim 2 or 3, which is applied to a step-and-repeat type semiconductor manufacturing apparatus and in which step movement is performed by the movement control means. 5. The alignment device according to claim 2, 3 or 4, wherein the calculation of the relation in said calculation means is performed at the time when a predetermined event occurs.