WO1997043785A1

WO1997043785A1 - Wafer aligning method

Info

Publication number: WO1997043785A1
Application number: PCT/JP1997/001590
Authority: WO
Inventors: Kiyonori Matsuno; Takeshi Okamoto; Shigeyuki Tada; Tomikazu Tanuki; Masaya Tanaka
Original assignee: Komatsu Ltd.
Priority date: 1996-05-14
Filing date: 1997-05-12
Publication date: 1997-11-20
Also published as: JPH09306977A

Abstract

A wafer aligning method for wafer inspection devices, etc., a pre-alignment and a fine alignment are performed by using the same camera, so that pre-alignment and fine alignment can be performed by using the same device.

Description

Wafer positioning method

Technical field

The present invention relates to a wafer positioning method in a device that requires precise positioning of a wafer, such as a wafer exposure device, a bonding device, an inspection device, and a dicing device used in a semiconductor device manufacturing process.

Background art

In the process of manufacturing semiconductor devices, it is necessary to perform precise positioning of the wafer, such as inspection, exposure, and dicing. For example, in inspection, it is necessary to know which chip in a wafer is being processed, and in dicing, chips are damaged if they are not cut along a predetermined pattern .

This alignment is performed by coarse alignment called pre-alignment, in which the orientation is roughly adjusted with reference to the position of the wafer's orientation flat (hereinafter, abbreviated as the orientation flat). It is divided into precise alignment called fine alignment based on the pattern drawn on the wafer, which can be achieved by roughly aligning the orientation flat. This is because the alignment becomes easier. In the conventional technology, this alignment and the fine alignment were performed by separate devices. In general, a technique was used in which a dedicated device was used to perform alignment, and then the wafer was transferred to a stage where fine alignment was performed.

The conventional technology will be described below using a wafer inspection apparatus as an example.

• Conventional example of briar alignment using a dedicated device

2. Description of the Related Art As a wafer inspection apparatus, there is one as disclosed in Japanese Patent Application Laid-Open No. HEI 6-324 837. The present invention includes a central rotating conveyance unit, various inspection units radially surrounding the center, and a repair unit for correcting a defective chip. At this time, prior to the transfer, the dedicated equipment performs brial alignment, the transfer means conveys the wafer to the various inspection units, and then performs fine alignment.Based on the results, various inspections are performed. Is going.

This prior art does not show a specific example of a device for briar alignment and fine alignment. 5 8 — There is the one described in 2045451. This publication discloses, as a conventional example, an example of a wafer alignment apparatus that detects the position of an orientation flat using a rotating roller. Further, in the invention of this publication, the position of the orificer is detected using optical means, and the alignment is performed.

As described above, in this conventional inspection device, the bridge A dedicated device is provided for the license, which is transported to the inspection stage where the fine alignment is performed. This complicates the control of the entire inspection device and results in a redundant process. In addition, there is a problem that the provision of a place for briar alignment increases the size and complexity of the inspection device.

• Conventional example of briar and fine alignment in one device

One of the means to solve these problems is to perform briar alignment and fine alignment with one apparatus as disclosed in Japanese Patent Application Laid-Open No. 4-35864. There is such an invention. A camera equipped with a low-magnification lens and a high-magnification lens is prepared, and a camera with a low-magnification lens performs brim alignment and a camera with a high-magnification lens performs fine alignment. It is. Alignment can be performed on one stage, saving space. However, the camera has to be switched between the brim and fine rim, which makes the process complicated. In addition, since the image is divided into two cameras via a beam splitter, precise optical axis alignment is required, and having two cameras also increases the size of the device. I do.

In addition, in this conventional example, only the parallelism of the wafer with the stage is adjusted, and the orientation of the wafer cannot be determined without detecting the orifice. In other words, this is an alignment technique for dicing that only requires parallelism, and it detects which chip is defective and provides the information. Inspection equipment that needs to feed back and repair as necessary, and bonding equipment that requires precise wires to be attached to chips, etc. It is not suitable for devices that must be positioned. In fact, this gazette also states that this is an alignment method for roofs that do not have an orthogonal alignment mark.

In addition to the above conventional examples, there is also an invention disclosed in Japanese Patent Publication No. 7-37889. In the present invention, a single camera detects the angle of a pattern engraved on a wafer, and performs pre-alignment and fine alignment. It does not solve the above-mentioned problem that the orientation cannot be detected.

Further, the invention disclosed in Japanese Patent Application Laid-Open No. 7-311025 discloses a wafer combining a two-dimensional inspection apparatus using an imaging device and a three-dimensional inspection apparatus using a confocal optical system. There is an example of an apparatus for inspecting the bumps above, but this also only describes the method of fine alignment, and discloses the means by which pre-alignment is performed. There is no.

As described above, the wafer alignment up to now usually requires a dedicated device for the pre-alignment, and a single device is used for the alignment of the bridge and the wafer. Nothing to do the alignment. A device that performs both alignments with a single device only detects the parallelism between the wafer and the stage and detects the absolute wafer position. Was not. The reason for this is that as a technology for performing fine alignment, as disclosed in Japanese Patent Publication No. 7-37889, the pattern and marks on a wafer are captured using a CCD camera. Detectors are common, but fine alignment requires extremely high precision, so the field of view of this CCD camera must be very narrow. This means that conventional methods could not perform brial alignment using only this narrow field of view. Disclosure of the invention

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and a method of positioning a wafer in a wafer inspection apparatus or the like according to the present invention uses the same alignment step as the brial alignment step and the fine alignment step. Perform with a camera.

Further, the above-mentioned brial alignment process includes a process of calculating the tilt angle of the wafer by image processing from an image captured by the camera, rotating the 0 stage on which the wafer is mounted by the tilt angle, and a process of rotating the camera. Moving the camera to the edges of the wafer at multiple locations to determine the center coordinates of the wafer by image processing and calculation; and moving the camera from the center of the wafer to four directions and processing the image to align the wafer. The method includes a step of detecting a flare and a step of rotating the stage so that the orifice is at a predetermined position.

In the above-mentioned fine alignment process, the characteristic pattern on the wafer and the design coordinates of the characteristic pattern are formed in at least two places. A step of pre-registering, a step of moving the camera near the registered characteristic pattern, and a step of detecting the actual coordinates of the point by means such as pattern matching. Calculating the inclination of the wafer and the shift in the XY direction from the coordinates. ―

ADVANTAGE OF THE INVENTION According to this invention, a bridge alignment and a fine alignment can be performed by the same apparatus, and the structure of the whole apparatus is simplified. Particularly in the case of a wafer inspection device, positioning can be performed using a two-dimensional inspection device, which makes it possible to use a wafer positioning device for a linear alignment and a fine alignment. There is no need to provide a separate application.

Also, since alignment can be performed using an orthogonal pattern, there is no need to provide alignment marks. Of course, for a wafer having an alignment mark, it may be used. Also, for wafers with different radii, simply entering a numerical value into the computer changes the distance to move the camera or stage, so there is no need to change the stage of the wafer positioning device. .

分解能 The resolution of the stage is usually about 0.1 °, which required a very expensive precision stage to perform more precise positioning.However, by obtaining data from the image, The precision positioning that is higher than the resolution of the stage is possible. Furthermore, when there are a plurality of inspection stages, the same hard software may be mounted on each stage, and maintenance is easy. BRIEF DESCRIPTION OF THE FIGURES

The invention will be better understood from the following detailed description and the accompanying drawings, which show embodiments of the invention. The embodiments shown in the accompanying drawings are not intended to specify the invention, but merely to facilitate explanation and understanding. FIG. 1 is a schematic structural explanatory view showing a wafer inspection apparatus utilizing the present invention.

Figure 2. Perspective view showing the X, Y, 0 stage.

Fig. 3. Fig. 3 is a perspective view showing a state in which a wafer is transferred between the stage and the transfer robot.

Figure 4. Plan view showing the wafer mounted on the stage.

Figure 5. The pattern on the wafer viewed from the camera.

FIG. 6A, FIG. 6B, FIG. 6C, and FIG. 6D are explanatory views showing different orientation flat positions when the angles are adjusted.

Fig. 7 is an explanatory diagram showing the procedure for moving the camera to determine the center position of the wafer.

Figure 8 is an explanatory diagram showing the procedure for moving the camera to detect the position of the wafer flat.

Figure 9 is an explanatory diagram showing the positional relationship between the 0 stage and the wafer at the time when pre-alignment is completed.

Figure 10: Pattern on wafer in data registration mode FIG.

Fig. 11-8. Fig. 11 B. Enlarged view of the field of view when setting a pattern. Fig. 12A. Fig. 12B. It is an enlarged view of the visual field at the time of the fine alignment.

Figure 1 3. This is an explanatory diagram showing the state of wafer transfer when multiple wafer inspection devices are aligned on a straight line.

Fig. 14 is a flow chart showing a part of the brial alignment process according to the present invention.

FIG. 5 is a flowchart showing another part of the bridge alignment process according to the present invention, in which b is connected to a in FIG.

Fig. 16 is a flowchart showing a fine alignment step according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic configuration of an apparatus for carrying out a wafer positioning method according to the present invention. In the figure, reference numeral 1 denotes a plane inspection apparatus, which uses a CCD camera or the like to cover the upper surface of the wafer. Images are taken and the position and area of each bump are calculated by image processing to detect abnormalities. Reference numeral 2 denotes a three-dimensional inspection device, which measures the height of each bump using the principle of a confocal microscope and detects abnormalities. Numeral 3 denotes an anchor device, which marks a laser including a bump in which an abnormality is detected by a laser link. 4 is for inspection This is the platform where the eha is placed.

In each of the above apparatuses, 5 is an XY stage and 6 is a 0 stage. These components are configured as shown in FIG. 2, and the XY stage 5 is a stage that can move in the X direction and the Y direction. 5 a, 5 b and mosquitoesゝlines cover Te Contact Ri, _c 7 where upper stages 5 a on the Θ stage 6 of this is mounted in a pivoting Ri CCD turtle Radea for photographing the surface of the wafer In this embodiment, the CCD camera also serves as a positioning device, and is mounted on each of the devices 1, 2, and 3 one by one. Reference numeral 8 denotes a height measuring confocal optical system for measuring the height of bumps and the like provided on the surface of the wafer, and includes, for example, a technology disclosed in Japanese Patent Application Laid-Open No. Hei 4-26959. Is used. Numeral 9 denotes an ink jet that blows ink to a defective chip, and 10 denotes a holder for storing wafers, and the wafers 11 are placed, for example, as a set of 25 wafers with the inspection surface facing upward. ing. As can be seen from the figure, the orientation of the orientation flat 24 at this time is random.

13 is a transfer port that moves in the scale (straight), φ (rotation), and Z (up and down) directions (not shown). The wafer 11 is attracted to the tip of the arm 12 by a vacuum chuck or the like. Thus, the apparatus is transported between the above-described apparatuses 1 to 4.

Reference numeral 14 denotes a CPU provided with a memory, which may be a CPU or a microcomputer, which controls stage management and inspection of each device. A plurality of CPUs 14 are connected to a main CPU 15 having the same memory by communication means such as Ethernet, and the CPU 15 manages the entire inspection apparatus. You.

The wafer positioning in each of the above apparatuses 1 to 4 is performed by the steps of (1) wafer transfer and installation, (2) bridge alignment, (3) file alignment, and (4) unloading and transfer processes. Consists of The main part in the present invention is (2) the part of the bridge, but the whole will be described as an example.

(1) Transfer and installation of wafers

In FIG. 1, the transfer robot 13 first picks up the wafer 11 from the wafer holder 10 and transfers it to the stage 6 of the plane inspection apparatus 1. The wafer 11 is mounted on the wafer holder 10 in a random posture.

As can be seen from FIG. 2, the stage 6 translates in the X and Y directions and rotates in the Θ direction.

As shown in FIGS. 2 and 3, the 0 stage 6 has a depression 16, and this depression is directed to the transport robot 13. When the arm 12 of the transport robot 13 with the wafer 11 enters into it, stops the suction, and moves down slightly, puts the wafer 11 on the 0 stage and lowers it. 1 Adsorb 1 and fix.

FIG. 4 shows a plan view of the wafer 11 placed on the stage 0 (the depression 16 is not shown). X and Y are XY coordinate axes based on the movement direction of the stage 6, and O is its origin. Reference numeral 20 denotes the camera's field of view (about a few millimeters square when inspecting fine objects such as bumps), and moves along the XY coordinates of the stage 6. 2 1 is the rotation center of the 0 stage It is. In actual equipment, the stage may move in each of the X, Υ, and あれば directions, or the camera may move along the XY axis, and the stage may be responsible for rotation in the e direction. In this embodiment, in any case, it is expressed as “moving the camera's field of view”.

Reference numeral 23 denotes an orthogonal pattern drawn on the wafer 11 for cutting a chip or an orthogonal pattern drawn on an IC, and the shape is known from CAD data. is there. In FIG. 4, X ′ and Y ′ are XY coordinate axes in a coordinate system (wafer coordinate system) based on the pattern of wafer 11, and 〇 ′ is its origin. The orifice 24 of the wafer 11 is substantially parallel to the X'-axis of the wafer coordinate system, and the upper left when the orifice 24 comes down is the origin of the wafer coordinate system. Reference numeral 22 denotes the center of the wafer 11, and the distance between the center of the wafer 11 and the rotation center 21 of the stage 6 is determined by the positioning error of the transfer robot 13 and the position of the wafer holder 10. It is not so difficult to reduce the power generated by rearrangement to a few millimeters. What is the relative position of the pattern 23, the wafer coordinate system X ', Y', O ', the orifice 24, and the center 22 of the wafer 11 shown in Fig. 4 with respect to the stage coordinate system XY? It is the positioning of the wafer 11 that detects this. In the future, simply referring to coordinates will refer to the stage coordinate system.

(2) Briar alignment

Figure 14 shows the pre-alignment flow. This flow The procedure of the brial alignment will be described with reference to FIGS. 5 to 9.

1) Adjust the orientation parallel to the X or Y axis of the stage coordinate system.

First, as shown in Fig. 5, the camera's field of view 20 is moved so that the center of rotation 21 of the stage fits in, and the image of the return 23 is captured. (It is not necessary to be near the center 21) (Step 1). From the image, the angle 0 1 between the no-turn and the stage Y axis is determined (step 2). As a method of obtaining 01, for example, pattern matching can be considered. Or, no. It may be obtained from the arrangement of bumps or the like instead of evening.

と When stage 6 is rotated counterclockwise so that the force becomes 0 and 0 (step 3), the orifice 24 becomes almost parallel to the X or Y axis of the stage coordinate system. As shown in A, Fig. 6B, Fig. 6C, and Fig. 6D, there are four possibilities. At this time, it is also possible to memorize only the value of stage 0 without actually rotating stage 6, and finally obtain the rotation angle by calculation.

2) Find the coordinates of the center 22 of the wafer.

An example in which the actual orificer is in the state shown in Fig. 6B will be described.

As shown in Fig. 7, the field of view of the camera is moved to the lower right by 45 ° to reach the X coordinate (xl) where the stage coordinates are (step 4). From here, the field of view is changed along the Y-axis. In step S5, the lower right edge of the wafer 11 is detected (step 5), and the coordinates (xl, y1) of the point A are obtained. The field of view is moved from the point A in the Y-axis plus direction (step 6), and when the upper right edge of the wafer 11 is detected, the coordinates (xl, y2) of the point B are obtained (step 6). 7). From the two points A and B, (yl + y2) 2 is calculated to calculate the center of the wafer 11 in the y direction (step 8). Next, the field of view is moved in the negative X-axis direction from point B (step 9), and the upper left edge of the wafer 11 is detected, and the coordinates (X 2, y 1) of the point C are obtained. (Step 10). Then, (xl + x2) Z2 is calculated from the points B and C to calculate the center of the wafer 11 in the X direction (step 11). The coordinates (xl + x2) / 2, (y1 + y2) 2 of the center 22 of the wafer 11 are obtained by both the steps 8 and 11. This is the same as obtaining the center 22 of the wafer 11 from the vertices A and B of the right-angled isosceles triangle inscribed in the wafer 11.

Here, instead of capturing the image of the camera during the movement, first move the camera to xl (step 4), and move it along the Y axis in the Y minus direction by a fixed distance. Then, the camera image may be captured at that location. This is because the work time is shortened. At this time, if no edge is detected in the camera, there are two possible cases: overshoot and undershoot. Either one can be determined by whether the camera image is bright or dark. If it is too far, return the camera to the Y direction. If it is not reached, proceed in the Y direction. At this point, the image is captured again. This is repeated to detect the edge of the wafer. This operation can be similarly performed in the steps (7) and (10) for obtaining the coordinates of the points B and C in the flow shown in FIG.

Here, X 1 is a force that can be appropriately determined. If the triangle formed by points A, B, and C is determined to be close to a right-angled isosceles triangle, X 1 and Y 2 have the same accuracy. Edge detection and coordinate calculation can be performed. For example, since the center of the wafer 22 and the center of rotation 21 of the stage are separated only by a few millimeters, consider a square inscribed in the wafer 11 and take X from the center of rotation by half the length of one side. Of course, you can move first in the plus direction of the X axis and then in the minus direction of the Y axis without moving diagonally, but move diagonally as described above. Obviously, the less time you do, the less travel time will be required.

At this time, care must be taken that the vertices A, B, and C of the triangle do not overlap the orthogonal part 24. Therefore, the amount of movement d 1 in the X direction from the starting point of the camera (in this case, the rotation center 21) to the point A is greater than the distance d 2 from the rotation center to the orifice 24. No. Considering the case where the orientation flats 24 are located up and down, d1 must be made to exceed half of the linear length d3 of the orientation flats. Since the dimensions of the reflector 24 and the wafer 11 are input in advance from the CAD data, such failures can be avoided. 3) Find out which of the four orientations shown in Figure 6A, Figure 6B, Figure 6C, and Figure 6D the orientation of the orifice 24 is.

In FIG. 8, the camera field of view is moved from the center 22 of the wafer 11 in four directions, up, down, left and right, almost by the radius of the wafer 11. Of the E, F, G, and H fields of view, the wafer edge is detected in the E, G, and H fields, but no edge is detected in F because the camera protrudes. That is, it can be determined that this is Orificer 24 part.

At this time, the brightness ratio of the image may be obtained instead of the edge detection. In E, G, and H, the illumination light is reflected off the wafer 11, whereas in F it is not reflected, so the brightest part is small and there is no certainty. In addition, the camera's field of view is moved from the center of the wafer 11 in four directions, up, down, left, and right, and edge detection is performed. it can.

4) Rotate the orientation flat 24 to the correct position and execute the pre-priming.

In the state where the center 22 of the wafer 11 is detected in step 11 in FIG. 14, it is not known whether the orientation flat 24 of this wafer 11 is located at any of the positions of FIGS. 6A to 6D. The explanation is based on the flow shown in 15.

The camera field of view is moved to the upper end G of the wafer 11 (step 12), and the edge at the upper end G is detected (step 13). If there is no edge, the wafer 11 is moved to the position shown in FIG. As shown in the figure, there will be an orifice 24 at this upper end. Rotate the edge 6 counterclockwise by an orientation flat rotation angle of 180 ° (step 14). As a result, the orificer 24 becomes, for example, a lower alignment position located on the lower side.

In step 13 above, when an edge is detected at the upper end G, the camera field of view is moved to the right end F of the wafer 11 (step 15), and the edge at the right end F is detected (step 15). In step 16), if there is no edge, wafer 11 is rotated counterclockwise as shown in FIG. 6B due to the force at which there is an orifice 24 on the right side. It rotates around the orientation flat rotation angle of 270 ° (step 17). As a result, the orifice 24 becomes the above-described briar alignment position located on the lower side.

Next, when an edge is detected at the right end F in step 16 described above, the camera field of view is moved to the lower end E of the wafer 11 (step 18), and the edge at this lower end E is detected. When the wafer is detected (step 19) and there is no edge, the wafer 11 has the orientation flat 24 on the lower side as shown in FIG. 6 (a). It can be seen that this is the alignment position, and the orientation flat rotation angle 0 2 at this time is zero (step 20).

In step 19, when an edge is detected at the lower end E, the camera field of view is moved to the left end H of the wafer 11 (step 21), and the edge at the left end H is detected. (Step 22) If there is no edge, wafer 11 will have orientation flat 24 on the left side as shown in Fig. 6 (d). Orifice rotation angle of 90 ° around 0 2 only Rotate (step 23).

By the above operation, the wafer 11 is brought into a briar alignment state in which the orientation flat 24 is located on the lower side. In the above operation, the number of times that the edge detector in four directions does not detect the edge should be only once at the position of the orientation flat 24, but this is detected two to four times, or even once. If not detected, it clearly indicates that the amount of movement of the camera's field of view from the wafer center 22 is too small or too large, in which case the correct pre-alignment operation is performed. Can not.

Therefore, Step 24 is provided after Step 23, and it is checked whether the number of times of non-detection of the edge is only once. If the number is one or more, the number of times this edge is not detected is detected (step 25). If the number is two to four, the moving distance of the camera field is increased. (Step 26). If it is not detected even once, the moving distance of the camera field is reduced (step 27).

In the state where it is detected in Step 24 that the number of times of edge non-detection is only one, the wafer 11 is rotated by the orifice rotation angle 0 2 and the orifice 24 is positioned on the lower side. Posture. Then, the briar alignment angle 0 P in this state becomes 0 p = 0 i + 0 2, the force that has already rotated stage 6 by θ 1 in step 3, and this 0 p Is the amount of deviation of the wafer 11 in the zero direction. At this time, if the force is larger than s180 °, it should be turned clockwise by the value obtained by subtracting 0p from the 180 ° force. As a result, the angles of the coordinate system between the stage 6 and the wafer 11 substantially match, as shown in FIG. 9, and the brial alignment is completed. The coordinates of the wafer center 22 from the wafer coordinate system are known, and the offset of the origin of the two coordinate systems is determined from the coordinates of the wafer center in the stage coordinate system obtained earlier and this briar alignment angle. The quantities (XP, yp) are determined (step 29). The offset amount (xp, yp) and the primary angle 0p are transferred from the CPU 14 to the main CPU 15 which manages the whole from the CPU 14 as a wafer-specific briar alignment parameter. This is used when the wafer 11 is transferred to another stage.

Depending on this direction, it is possible to perform alignment using a CCD for fine alignment that shows a narrow field of view.

(3) Fine alignment

The following is an example of a fine alignment. At this time, it is assumed that the stage has been aligned.

Figure 16 shows the flow of the fine alignment. With reference to this flow and FIGS. 10 to 12, the method of fine alignment will be described.

1) Pattern registration

This pattern registration need not be performed for each wafer 11 as long as the pattern of wafer 11 is the same. As a procedure, first, only pattern registration for one wafer 11 is performed before inspection. It can be done as a step.

First, two characteristic patterns are selected from the wafer 11 and registered as images. For example, the parts I and J in the wafer 11 shown in FIG. 10 correspond thereto. Figure 11 shows the images of I and J registered in (a) and (b).

At this time, if there is an alignment mark on the wafer 11, this may be registered.

Next, the wafer coordinates (x 3 ′, y 3 ′) and (x 4 ′, y 4 ′) of the most characteristic points I 1 and J 1 in these images are registered. The images of I and J and the wafer coordinates of I 1 and J 1 are reference points for performing fine alignment.

2) Move the camera

Based on the previous alignment, the stage is calculated from the offset amount (xp, yp) of the coordinate system and the wafer coordinates (χ3 ', y3') and (x4 ', y4') of II and JI. The coordinates (x3, y3) and (x4, y4) of the coordinate system I and Jl are calculated, and the camera is moved there (step 1). As described above, the accuracy of the transfer system is only a few millimeters, and the pattern can be viewed even when the wafer 11 is transferred. If the pattern is not in the field of view, you can move the camera up, down, left and right to search for the pattern.

3) Pattern matching

Figure 12 shows newly captured images of the fields of view K and L. This is followed by pattern matching with the registered images I 1 and J 1 (step 2), and the registered images I and J are found (step 2). Step 3). If the camera cannot be found at this time, move the camera up, down, left, and right (Step 4). Thus, the coordinates (x5, y5), (x6, y6) of the characteristic points K1, L1 corresponding to the characteristic points I1, J1 of the registered images I, J are obtained. Can be requested.

4) 0-direction fine alignment

The slope of the straight line connecting K 1 and L 1 (y 6 — y 5) / (x 6-x 5) and the slope of the straight line connecting II and J 1 (y 4 '— y 3') / (X 4 ' -X3 ') is compared, a tilt 0t in the direction of the wafer is obtained (step 6), and the 0-stage is rotated for correction. This loop of photographing, pattern matching, and S-stage rotation is repeated until the tilt becomes equal to or less than the resolution of stage 0 (step 7).

However, the resolution of the S stage is usually about 0.1 °. For example, if the angle deviates by 0.1 °, a displacement of 100 m or more will occur around the 150 mm diameter stage. Wake up and affect inspection and measurement. For this reason, the pattern is re-measured with the 0 stage finally adjusted, and the stage coordinates (xfl, yfl) and (f2, yf2) of the points K1 and L1 are obtained (step 8). From the comparison between the slope of this line (yf 2 — yf 1) / (xf 2-xf 1) and (y 4 '— y 3') / (x 4 '-x 3'), Obtain the amount of inclination Θ f and correct at the time of inspection.

5) X-Y fine alignment

Stage coordinates (xil, yf 1) of mark position K l, L 1, From the (f 2, yf 2) force, the relation between the wafer 11 and the pattern with respect to the XY stage can be specified. Based on this data, the XIII stage may be actually moved, or as a final parameter, it may be corrected on hardware or software at the time of inspection.

(4) Unloading, transporting, next process

After performing the plane inspection, the stage 6 rotates by 0 ρ in the opposite direction to the pre-alignment, and directs the depression 16 to the transfer robot 13. The robot 13 unloads the wafer 11 from the plane inspection device 1 and loads it into the three-dimensional inspection device 2. The same procedure can be used for the anchor. Each device has the same image sensor and image processing device (hardware and software) as the flat surface inspection device, and can perform positioning according to the above procedure.

At this time, cpu14 has received the prior alignment data 0p, and the rotation is completed by rotating stage 0 by 0p. From here, perform the file alignment according to the procedure of “(3) File alignment” and start the next inspection and processing. There is no need to register the pattern again.

However, in the embodiment shown in FIG. 1, the robot is located at the center of the apparatus, and the inspection apparatus surrounds the periphery in a circular shape. Therefore, the robots are used in the plane inspection apparatus 1, the three-dimensional inspection apparatus 2, and the inker 13. The angle at which the wafer enters the wafer may be different. This angle is preset as an offset amount, added to 6ρ, and the stage 6 is rotated to perform pre-alignment. As shown in FIG. 13, if the transfer robot 13a is arranged so as to always carry the fuel at a fixed angle with respect to the apparatus, this offset is not necessary.

Claims

The scope of the claims

1. A method of positioning a wafer in a wafer inspection device or the like, which performs a brial alignment process with a camera and then performs a fine alignment process with the same camera.

2. The pre-alignment process calculates the tilt angle of the wafer by image processing from the image captured by the camera, rotates the stage 0 on which the wafer is mounted by this tilt angle, and sets the camera Moving to the edges of the wafer at multiple locations to determine the center coordinates of the wafer by image processing and calculation; and moving the camera from the center of the wafer to four directions to shift the wafer's orifice by image processing. 2. The wafer positioning in a wafer inspection apparatus according to claim 1, further comprising a step of detecting and a step of rotating a zero stage so that the orificer is at a predetermined position. Method.

3. In the final alignment process, the characteristic pattern on the wafer and its design coordinates are registered in at least two places in advance, and the registered characteristic pattern is registered. Moving the camera to the vicinity, detecting the actual coordinates of the point by means such as pattern matching, and calculating the tilt of the wafer and the displacement in the XY direction from the coordinates. The method for positioning a wafer in a wafer inspection apparatus or the like according to claim 1.