JP2023045194A - Pre-alignment device and method - Google Patents

Abstract

To provide a pre-alignment device and a method capable of successfully performing pre-alignment processing even when no notch is formed in a wafer or notches are hardly detected.SOLUTION: A pre-alignment device for performing pre-alignment of a wafer having an alignment mark indicating a direction of a wafer, includes: a sub-chuck 34 that can hold and rotate the wafer; an alignment mark detection unit 36 for detecting a position of the alignment mark of the wafer held by the sub-chuck 34; and a correction unit for correcting a direction of the wafer by changing a rotation position of the sub chuck 34 based on the position of the alignment mark detected by the alignment mark detection unit 36.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wafer pre-alignment apparatus and method, and more particularly to a pre-alignment apparatus and method suitable for pre-alignment of a wafer having no notch or a notch that is difficult to detect.

In a semiconductor manufacturing process, a wafer is inspected while placed on a stage of an inspection apparatus. In order to inspect the wafer with high accuracy, it is necessary to mount the wafer on the stage after performing pre-alignment processing so that the wafer is oriented in a predetermined direction with respect to the stage.

Therefore, various techniques for performing pre-alignment processing have been conventionally proposed. For example, Patent Literature 1 describes a substrate positioning system that adjusts the orientation of a substrate provided with a notch that indicates the orientation of the substrate on the periphery. This substrate positioning system includes an abutting member that abuts against the edge of the notch, a moving unit that moves the abutting member around a predetermined rotation center, and a substrate that moves the substrate so that the center of the substrate coincides with the rotation center. After the center of the substrate is aligned with the center of rotation by the defining means, the contact portion of the contact member is brought into contact with the notch of the substrate to contact The wafer is rotated and oriented by moving the member in an arc.

Further, in Patent Document 2, three line sensors are used to detect the position coordinates of three points on the edge of the wafer and the position coordinates of the notch, and based on the detection results, the center position and orientation of the wafer are detected. technique is described.

International publication WO2005/055315 JP 2009-253197 A

By the way, the techniques described in Patent Documents 1 and 2 are based on the premise that a notch is formed in the wafer. There was a problem that it could not be performed well.

In addition, in the semiconductor manufacturing process, chipping may occur in the wafer during processing, resulting in the chipping of the cutout portion of the wafer, or making it difficult to detect the cutout. In such a case, since the notch cannot be detected satisfactorily, there is a possibility that the orientation of the wafer cannot be accurately corrected.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances. It is an object to provide an apparatus and method.

In order to solve the above problems, a prealignment apparatus according to a first aspect of the present invention is a prealignment apparatus that performs prealignment of a wafer having an alignment mark indicating the orientation of the wafer, the wafer being held and rotated. possible sub-chuck, an alignment mark detection unit for detecting the position of the alignment mark of the wafer held by the sub-chuck, and the rotation position of the sub-chuck is changed based on the position of the alignment mark detected by the alignment mark detection unit. an orientation correcting unit that corrects the orientation of the wafer by

A prealignment apparatus according to a second aspect of the present invention, in the first aspect, further includes an eccentricity measurement unit for measuring the eccentricity of the center of the wafer with respect to the rotation center of the sub-chuck; an eccentricity correction unit that corrects eccentricity of the wafer by changing the relative position of the wafer with respect to the sub-chuck based on the amount of eccentricity.

A pre-alignment device according to a third aspect of the present invention is the second aspect, wherein the eccentricity measuring unit comprises a laser light projecting unit and a laser light receiving unit for receiving the laser light emitted from the laser light projecting unit. and a laser sensor capable of detecting the wafer held by the sub-chuck.

A prealignment device according to a fourth aspect of the present invention is the second aspect, wherein the eccentricity measurement unit receives the non-laser light projecting unit and the non-laser light emitted from the non-laser light projecting unit. and a non-laser light-receiving part, and is composed of a total light amount detection type optical sensor that outputs the total light amount obtained by the non-laser light-receiving part.

In order to solve the above problems, a prealignment apparatus according to a fifth aspect of the present invention is a prealignment apparatus that performs prealignment of a wafer having alignment marks indicating the orientation of the wafer, the wafer being held and rotated. Possible first sub-chuck and second sub-chuck, a notch detector for detecting the position of the notch indicating the orientation of the wafer held by the first sub-chuck, and alignment of the wafer held by the second sub-chuck Rotation of the first sub-chuck or the second sub-chuck based on the alignment mark detection unit that detects the position of the mark and the position of the notch detected by the notch detection unit or the position of the alignment mark detected by the alignment mark detection unit. an orientation correction unit that corrects the orientation of the wafer by changing its position.

A prealignment apparatus according to a sixth aspect of the present invention is, in the fifth aspect, the eccentricity measurement unit for measuring the eccentricity of the center of the wafer with respect to the center of rotation of the first sub-chuck, and a non-laser light receiving portion for receiving non-laser light emitted from the non-laser light projecting portion, and outputting the total light quantity obtained by the non-laser light receiving portion. and a first eccentricity measuring section configured by a sensor, and an eccentricity measuring section for measuring the eccentricity of the center of the wafer with respect to the center of rotation of the second sub-chuck, comprising a laser light projecting section and a laser light receiving section. a second eccentricity measuring unit configured by a laser sensor capable of detecting the wafer held by the second sub-chuck; and a first eccentricity measuring unit. an eccentricity correction unit that corrects the eccentricity of the wafer by changing the relative position of the wafer with respect to the first sub-chuck or the second sub-chuck based on the eccentricity amount measured by the amount measuring unit or the second eccentricity amount measuring unit; Prepare.

In order to solve the above problems, a prealignment method according to a seventh aspect of the present invention is a prealignment method for performing prealignment of a wafer having an alignment mark indicating the orientation of the wafer, wherein the wafer is held and rotated. an alignment mark detection step for detecting the positions of alignment marks on a wafer held by a possible sub-chuck; and an orientation correction step of correcting the orientation.

A prealignment method according to an eighth aspect of the present invention is, in the seventh aspect, an eccentricity measuring step of measuring the eccentricity of the center of the wafer with respect to the rotation center of the sub-chuck, and the eccentricity measured in the eccentricity measuring step and an eccentricity correction step of correcting the eccentricity of the wafer by changing the relative position of the wafer with respect to the sub-chuck based on.

A pre-alignment method according to a ninth aspect of the present invention is the eighth aspect, wherein the eccentricity measuring step includes a laser light projecting section and a laser light receiving section for receiving the laser light emitted from the laser light projecting section. and a laser sensor capable of detecting the wafer held by the sub-chuck.

A prealignment method according to a tenth aspect of the present invention is the eighth aspect, wherein the eccentricity measuring step receives a non-laser light projecting portion and a non-laser light emitted from the non-laser light projecting portion. and a non-laser light-receiving portion, and a total light amount detection type optical sensor that outputs the total light amount obtained by the non-laser light-receiving portion.

In order to solve the above problems, a prealignment method according to an eleventh aspect of the present invention is a prealignment method for prealigning a wafer having an alignment mark indicating the orientation of the wafer, wherein the wafer is held and rotated. A notch detection step of detecting the position of the notch indicating the orientation of the wafer held by the first sub-chuck, and the position of the alignment mark of the wafer held by the second sub-chuck capable of holding and rotating the wafer. a detection step of selectively performing a detection step of detecting the position of the notch or the position of the alignment mark detected in the detection step, the rotation position of the first sub-chuck or the second sub-chuck is changed and an orientation correction step of correcting the orientation of the wafer by causing the

A prealignment method according to a twelfth aspect of the present invention is, in the eleventh aspect, the eccentricity measuring step of measuring the eccentricity of the center of the wafer with respect to the center of rotation of the first sub-chuck, and a non-laser light receiving portion for receiving non-laser light emitted from the non-laser light projecting portion, and outputting the total light quantity obtained by the non-laser light receiving portion. and a step of measuring the eccentricity of the center of the wafer with respect to the center of rotation of the second sub-chuck. and a second eccentricity measurement step that is performed using a laser sensor capable of detecting a wafer, and a laser light receiving section that receives laser light emitted from the optical section. and an eccentricity correction step of correcting the eccentricity of the wafer by changing the relative position of the wafer with respect to the first sub-chuck or the second sub-chuck based on the eccentricity measured in the eccentricity measurement step.

According to the present invention, even if a notch is not formed in the wafer or it is difficult to detect the notch, it is possible to perform pre-alignment processing satisfactorily.

1 is a perspective view showing a main part of an inspection device to which a prealignment device according to a first embodiment is applied; FIG. FIG. 4 is an enlarged perspective view of the vicinity of a second sub-chuck; 4 is a functional block diagram of a control unit in the first embodiment; FIG. FIG. 4 is a diagram showing an example of a wafer that can be pre-aligned well in the first embodiment; 4 is a flow chart showing an example of a pre-alignment method according to the first embodiment; 6 is a flow chart showing an example of mark pre-alignment in the pre-alignment method according to the first embodiment. It is a figure explaining eccentricity correction by a laser pre-alignment sensor. It is a figure explaining the detection of an alignment mark by an alignment mark detection part. 4 is a flow chart showing an example of notch prealignment in the prealignment method according to the first embodiment. FIG. 11 is a perspective view showing a main part of an inspection device to which a prealignment device according to a second embodiment is applied; It is a functional block diagram of a control part in a 2nd embodiment. 9 is a flow chart showing an example of a pre-alignment method according to the second embodiment;

Embodiments of a prealignment apparatus and method according to the present invention will be described below with reference to the accompanying drawings. In the drawings, basically the same members and steps are denoted by the same reference numerals, and description thereof is omitted.

[First Embodiment]
FIG. 1 is a perspective view showing essential parts of an inspection apparatus (prober) 1 to which a prealignment apparatus according to the first embodiment is applied. FIG. 2 is an enlarged perspective view of the vicinity of the second sub-chuck. 1 and 2, the direction parallel to the stage 11, the first sub-chuck 32 and the second sub-chuck 34 (the surface of the wafer W) is the X direction and the Y direction perpendicular to the X direction. The direction perpendicular to the Y direction is the Z direction.

The prealignment apparatus according to the first embodiment not only can satisfactorily prealign a wafer W having a notch N in the outer edge as in the conventional art, but also can prealign a wafer without a notch N, which could not be prealigned in the conventional art. W can also be well pre-aligned. The details of the wafer W will be described later.

As shown in FIG. 1, the inspection apparatus 1 includes a body section 10, a load port section 20, a loader section 30, and a control section 40 (see FIG. 3). The loader section 30 corresponds to the prealignment device of the present invention. The main body 10 includes a stage 11, a main chuck (not shown), a probe card (not shown), and a test head (not shown).

A main chuck is provided on the stage 11 and holds the wafer W fixedly. A probe card has a plurality of probe needles and is electrically connected to the test head. The test head is electrically connected to a tester main body (not shown), supplies power and electrical signals from the tester main body to the probe card, and returns response signals from the probe card to the tester main body. When performing an electrical characteristic test (probe test), in the main body 10, the wafer W placed on the stage 11 is fixed by the main chuck, and each probe needle is attached to each chip formed on the wafer W. While in contact with the electrodes, the test head supplies power and electrical signals to each chip through each probe needle of the probe card. Furthermore, the test head transmits a response signal from each chip to the tester body, and the tester body analyzes the response signal to inspect the electrical characteristics of each chip. The main chuck is, for example, a vacuum chuck or an electrostatic chuck. Since a known configuration is applied to the configuration of the main body 10, detailed description thereof will be omitted.

The load port section 20 includes a storage section (not shown) that stores the wafer W therein. The wafer W is unloaded from the load port section 20 to the loader section 30 by the arm 31 of the loader section 30 .

The loader section 30 pre-aligns the wafer W, and mounts the wafer W at a predetermined position on the stage 11 in a predetermined orientation with respect to the stage 11 . The loader section 30 includes an arm 31 , a first sub-chuck 32 , a standard pre-alignment sensor 33 , a second sub-chuck 34 , an ID detection section 35 , an alignment mark detection section 36 and a laser pre-alignment sensor 37 . Prepare.

The arm 31 moves in any of the X, Y, and Z directions by extending, contracting, rotating, and moving up and down by a drive unit (not shown). A wafer W is transferred to and from the stage 11 of the unit 10 . Further, the transfer arm 31 moves the wafer W relative to the first sub-chuck 32 or the second sub-chuck 34 in order to correct the eccentricity of the wafer W relative to the rotation axis (rotation center) of the first sub-chuck 32 or the second sub-chuck 34 . change the relative position of

The first sub-chuck 32 corresponds to the “first sub-chuck” of the invention, and holds the wafer W conveyed by the arm 31 . Also, the first sub-chuck 32 is rotatable by a rotation mechanism (not shown). The first sub-chuck 32 is, for example, a vacuum chuck or an electrostatic chuck.

The standard pre-alignment sensor 33 is provided near the first sub-chuck 32, for example. The standard pre-alignment sensor 33 corresponds to the "eccentricity measuring unit" and "optical sensor" of the present invention, and measures the wafer W held by the first sub-chuck 32 relative to the center of rotation of the first sub-chuck 32. and the notch N formed in the wafer W is detected. Details of the standard pre-alignment sensor 33 will be described later.

The second sub-chuck 34 corresponds to the “sub-chuck” and “second sub-chuck” of the present invention, and has substantially the same configuration as the first sub-chuck 32 . That is, the second sub-chuck 34 holds the wafer W transferred by the arm 31 . Also, the second sub-chuck 34 is rotatable by a rotation mechanism (not shown).

As shown in FIGS. 1 and 2, an ID detector 35, an alignment mark detector 36, and a laser pre-alignment sensor 37 are provided near the second sub-chuck 34. As shown in FIGS. The ID detector 35 detects wafer identification information (wafer ID) formed on the surface of the wafer W. FIG. Examples of the ID detection unit 35 include various cameras such as a CCD (Charge Coupled Device) camera and a CMOS (Complementary Metal Oxide Semiconductor) camera.

The alignment mark detection unit 36 corresponds to the "alignment mark detection unit" of the present invention, is arranged facing the surface of the wafer W held by the second sub-chuck 34, and detects the wafer held by the second sub-chuck 34. An alignment mark M formed on the surface of W is detected. Alignment marks M will be described later. The alignment mark detection unit 36 is, like the ID detection unit 35, various cameras such as a CCD (Charge Coupled Device) camera and a CMOS (Complementary Metal Oxide Semiconductor) camera. 1 and 2, the ID detection section 35 and the alignment mark detection section 36 are separated, but the alignment mark detection section 36 may be used as the ID detection section 35 as well.

The laser prealignment sensor 37 corresponds to the "eccentricity measuring unit" and the "laser sensor" of the present invention, and measures the wafer W held by the second sub-chuck 34 relative to the center of rotation of the second sub-chuck 34. Measure the eccentricity of the center of the Specifically, the laser pre-alignment sensor 37 irradiates the vicinity of the outer edge of the wafer W with a laser beam (parallel light) substantially perpendicular to the surface of the wafer W, so that the coordinates of the outer edge (edge) of the wafer W are determined. to get Furthermore, the laser pre-alignment sensor 37 calculates the position of the center of the wafer W based on the coordinates of the outer edge of the wafer W, and calculates the amount of eccentricity of the center of the wafer W with respect to the rotation center of the second sub-chuck 34 . Details of the laser pre-alignment sensor 37 will be described later.

The control unit 40 controls the probe test of the wafer W in the main unit 10 and the transfer and pre-alignment of the wafer W in the loader unit 30 based on a predetermined operation program.

The functional configuration of the control unit 40 will be described below with reference to FIG. The control unit 40 comprehensively controls various devices that constitute the inspection apparatus 1 . The control unit 40 includes a body control unit 41 , an arm control unit 42 , a determination unit 43 , a standard prealignment control unit 44 , a mark prealignment control unit 45 and an input/output unit 47 .

The body control section 41 controls inspection of the wafer W on the stage 11 by the body section 10 .

Arm control unit 42 controls the operation of arm 31 . Specifically, the arm control unit 42 takes out the wafer W from the load port unit 20, causes the first sub-chuck 32 or the second sub-chuck 34 to hold the wafer W based on the determination result of the determination unit 43, and prealigns the wafer W. The arm 31 is controlled so as to unload the wafer W for which the process has been completed to the stage 11 .

The determination unit 43 determines whether to perform notch pre-alignment or mark pre-alignment on the wafer W based on pre-alignment setting information, which will be described later. It outputs to the unit 44 and the mark pre-alignment control unit 45 .

The standard pre-alignment controller 44 controls pre-alignment of the wafer W by the standard pre-alignment sensor 33 . The mark pre-alignment control unit 45 controls pre-alignment of the wafer W by the alignment mark detection unit 36 and the laser pre-alignment sensor 37 .

The input/output unit 47 is an interface for inputting/outputting operation information between the user and the control unit 40 . Examples of the input/output unit 47 include a touch panel and a keyboard. Although a touch panel is shown as an example of the input/output unit 47 in FIG. Also, the input/output unit 47 may be directly connected to the inspection device 1 or may be connected to the inspection device 1 via a wired or wireless network.

The main body control unit 41, the arm control unit 42, the determination unit 43, the standard prealignment control unit 44, and the mark prealignment control unit 45 that constitute the control unit 40 are, for example, one or more personal computers, workstations, PLCs ( Programmable Logic Controller), etc. In addition, the control unit 40 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a storage device (not shown) that stores a control program (for example, a HDD (Hard Disk Drive) or SSD (Solid State Drive)), and It includes SDRAM (Synchronous Dynamic Random Access Memory) that can be used as a work area for the CPU.

Next, a wafer W that can be satisfactorily prealigned by the prealignment apparatus according to the first embodiment will be described with reference to FIG. Reference numerals 4G and 4H in FIG. 4 denote examples of wafers W that can be satisfactorily prealigned by prealignment (notch prealignment) of the wafer W by the standard prealignment sensor 33 .

Reference numeral 4G in FIG. 4 denotes a wafer W having a notch N formed in the outer edge. Here, the notch N is formed to indicate the orientation of the wafer W, and extends a part of the outer edge of the wafer W from one surface to the other surface of the wafer W in the thickness direction of the wafer W. It is a partial chip on the periphery formed by cutting uniformly along.

4G and others in FIG. 4 show the case where the notch N is a V-shaped notch as an example. However, the shape of the notch N is not limited to this example, and may be any shape such as orientation flat, U-shaped, or the like. In the case of the wafer W indicated by reference numeral 4G, pre-alignment processing is performed using the notch as a reference. Examples of the material of the wafer W include glass and silicon.

Reference numeral 4H in FIG. 4 indicates that the wafer W is attached to the support substrate S while the relative positions of the support substrate S and the wafer are well aligned so that the center of the support substrate S and the center of the wafer W coincide with each other. 1 shows a wafer W attached and with a notch N formed therein. For example, in a semiconductor manufacturing process, after a pattern is formed on the front surface of a wafer W, a back grinding process may be performed in which the entire back surface of the wafer W is ground to reduce the thickness. When the thickness of the wafer W becomes thin, the wafer W tends to bend, so that it may become difficult to transport the wafer W alone. In this case, the support substrate S is adhered to the rear surface of the wafer W using a tape, an adhesive, or the like, and the wafer W is transported. As the support substrate S, for example, various types of glass such as quartz glass, borosilicate glass, alkali-free glass, etc. are preferably used.

If the relative positions of the support substrate S and the wafer W are well aligned as indicated by reference numeral 4H in FIG. It becomes possible.

Reference numerals 4A to 4F in FIG. 4 denote examples of wafers W that can be satisfactorily prealigned by prealignment (prealignment for marks) of the wafer W by the alignment mark detection unit 36 . All of the wafers W indicated by reference numerals 4A to 4E are examples in which detection is difficult with the above-described notch prealignment.

In the first embodiment (similarly to the second embodiment, which will be described later), even if the notch N is not formed in the wafer W or the notch N is difficult to detect, good prealignment processing is performed by mark prealignment. In order to be able to perform the above, the wafer W has an alignment mark M formed on either one of the front and back surfaces of the wafer W (on the front surface of the wafer W in this example) to indicate the orientation of the wafer W. used (see FIG. 8). The alignment mark M is a planar mark or a very shallow mark having an arbitrary shape and color that can be detected by the alignment mark detection section 35 . The alignment mark M differs from the notch N in that it does not affect the shape of the outer periphery.

In the following description, the alignment mark M is an x mark (cross mark) as an example, but the alignment mark M is not limited to this example. For example, the alignment mark M may be a mark of another shape such as a circle or a square, or any shape such as a part of the wafer ID attached to the surface of the wafer W. FIG.

The alignment marks M are formed by any known technique, for example, by the user of the inspection apparatus 1, if necessary. Also, the alignment mark M is formed at a predetermined position on the wafer W so that the alignment mark detector 35 can detect it. Specifically, the alignment mark M is formed at a position on the surface of the wafer W that can be detected by the alignment mark detector 36 .

Reference numeral 4A denotes an example of a wafer W in which no notch N is formed (hereinafter referred to as a wafer without notch N). Reference numeral 4B denotes an example of a wafer W in which notches N and chippings C coexist at the outer edge (hereinafter referred to as wafers with notches N that are difficult to detect).

For example, chipping C may occur at the outer edge of the wafer W during processing of the wafer W even if the notch N is formed in the outer edge. In such a case, since the notch N and the chipping C coexist, it becomes difficult to detect the notch N, and therefore prealignment processing by notch prealignment becomes difficult.

In the first embodiment, the wafers W indicated by reference numerals 4A and 4B are subjected to notch pre-alignment but mark pre-alignment, so that pre-alignment processing can be performed satisfactorily.

Reference numeral 4C denotes an example of a wafer W without notches N to which the support substrate S is attached. Reference numeral 4D indicates an example of a wafer W with a notch N to which the support substrate S is attached and which is difficult to detect. In the first embodiment, as indicated by reference numerals 4C and 4D, even the wafer W to which the support substrate S is attached can be satisfactorily prealigned by mark prealignment.

Reference numeral 4E denotes an example of a wafer W without notches N attached onto the support substrate S in a state of being off-center from the center of the support substrate S. FIG. Since the eccentricity correction is performed using the laser prealignment sensor 37 in the first embodiment, even the wafer W attached on the support substrate S in a state of eccentricity from the center of the support substrate S can be satisfactorily corrected by the mark prealignment. A pre-alignment process can be performed.

A reference numeral 4F indicates an example of a transparent wafer W in which a notch N is formed. In the invention described in Patent Document 2, which uses a line sensor, the notch N formed in the transparent wafer W cannot be detected satisfactorily, so pre-alignment processing cannot be satisfactorily performed. However, in the first embodiment, mark pre-alignment is performed by detecting the alignment mark M formed on the surface of the transparent wafer W using the alignment mark detection unit 36, so that the pre-alignment process is performed satisfactorily. be able to.

Next, a pre-alignment method according to the first embodiment will be described with reference to FIGS. 5 to 9. FIG. First, the general processing flow of the prealignment method according to the first embodiment will be described with reference to FIG.

First, the arm control section 42 of the control section 40 takes out the wafer W from the load port section 20 by the arm 31 (step S10). Subsequently, the determination unit 43 of the control unit 40 determines the pre-alignment process to be performed on the wafer W taken out in step S10 (step S12).

Specifically, before starting the inspection of the wafer W, the user sets which prealignment process to perform, standard prealignment or mark prealignment. The setting of the alignment process by the user may be set for each wafer lot, or may be set for each wafer W individually. Then, the determining unit 43 determines the sub-chuck to which the wafer W taken out in step S10 is to be transferred based on the information (pre-alignment setting information) set by the user, and thereby performs pre-alignment on the wafer W. Determine alignment processing.

Based on the determination result in step S12, the arm controller 42 transfers the wafer W to either the first sub-chuck 32 or the second sub-chuck 34 (step S13). Subsequently, mark pre-alignment (step S14) or notch pre-alignment (step S15) is performed based on the determination result in step S12. Details of steps S14 and S15 will be described later. After the pre-alignment process is performed in step S14 or S15, the wafer W is transferred to the stage 11, and the process ends.

Subsequently, the mark pre-alignment in step S14 of FIG. 5 will be described in detail with reference to FIG. This process is performed on wafers W as indicated by reference numerals 4A to 4F in FIG. First, when the wafer W is transferred onto the second sub-chuck 34, the mark pre-alignment control unit 45 fixes and holds the wafer W by the second sub-chuck 34 (step S20). Subsequently, while the second sub-chuck 34 is rotated by a rotation mechanism (not shown), the laser pre-alignment sensor 37 is used to measure the coordinates of the outer edge (edge) of the wafer W, thereby determining the rotational axis of the second sub-chuck 34. is measured (step S21).

The eccentricity correction by the laser pre-alignment sensor 37 will be described below with reference to FIG. As shown in FIG. 7, the laser pre-alignment sensor 37 has a laser emission surface (laser light projection part) 371 on one surface side of the flat wafer W (the upper surface side in FIG. A laser type sensor having a laser light receiving surface (laser light receiving portion) 372 on the lower surface side in FIG. Consists of As the laser pre-alignment sensor 37, for example, a laser length measuring sensor (type: ZX-GT) manufactured by Omron can be used. The laser pre-alignment sensor 37 is an example of a "laser sensor" constituting the "eccentricity measuring section" and the "second eccentricity measuring section" of the present invention.

The laser emission surface 371 of the laser pre-alignment sensor 37 irradiates the surface of the wafer W with a laser beam having a width along the radial direction of the wafer W from one side of the wafer W in a substantially vertical direction. The laser light receiving surface 372 of the laser pre-alignment sensor 37 receives the laser light and measures the light amount of the laser light. As a result, the distribution of the amount of laser light in the radial direction of the wafer W is obtained. Since the laser light is reflected or blocked by the outer edge of the wafer W, in the distribution of the light intensity of the laser light in the radial direction of the wafer W, the position of the outer edge of the wafer W is a position where the light intensity changes locally stepwise. Observed. Therefore, the position coordinates of the outer edge of the wafer W can be measured using the laser pre-alignment sensor 37 .

By performing this measurement for the entire circumference of the wafer W, the mark prealignment control unit 45 can measure the position coordinates of the outer edge of the wafer W for the entire circumference of the wafer. Then, the mark prealignment control unit 45 determines the positional deviation amount of the center of the wafer W with respect to the rotation axis of the second sub-chuck 34 (that is, the amount of eccentricity with respect to the rotation axis) from the change in the position coordinates of the outer edge of the wafer W over the entire circumference ) is measured. Since the method for calculating the eccentricity is self-explanatory, detailed description is omitted.

On the other hand, as the standard pre-alignment sensor 33, an optical sensor that detects the total amount of light is used. This total light amount detection type optical sensor (that is, the standard pre-alignment sensor 33) measures the amount of eccentricity of the center of the wafer W with respect to the rotation center of the first sub-chuck 32 and It is used to detect the formed notch N, and the measurement light (non-laser light) is emitted to the outer edge (edge) of the wafer W from the measurement light irradiation surface (non-laser light projection part) on one side. It is possible to irradiate and detect the total amount of light by the light receiving element (non-laser light receiving portion) on the other side. For example, if the wafer W is not eccentric with respect to the rotation axis of the first sub-chuck 32, the outer edge of the wafer W does not move even if the wafer W is rotated. It does not change.

When the wafer W is eccentric, when the wafer W is rotated, the outer edge of the wafer W moves, so that the detected value of the total amount of light changes in a sine wave. can be detected as However, when the wafer W is made of a transparent material such as a glass wafer or an acrylic wafer, most of the measurement light passes through the wafer W and is detected by an optical sensor that detects total light intensity. The total amount of light hardly changes. For this reason, depending on the type of wafer W, the eccentricity of the wafer W may not be able to be measured by the total light amount detection type optical sensor (that is, the standard pre-alignment sensor 33). Similarly, when the wafer W is attached to the transparent support substrate S, the eccentricity of the wafer W may not be measured. The standard pre-alignment sensor 33 is an example of an "optical sensor" that constitutes the "eccentricity measuring section" and the "first eccentricity measuring section" of the present invention.

On the other hand, the laser pre-alignment sensor 37 employed in the first embodiment can linearly detect the distribution of the light intensity of the laser light in addition to the total light intensity of the laser light. In the laser pre-alignment sensor 37, the light intensity of the laser light locally decreases at the position of the outer edge (edge) of the wafer W. Therefore, the position where the light intensity of the laser light decreases on the detection line is regarded as the outer edge (edge) of the wafer W. can be detected as

By performing this outer edge detection over the entire 360° circumference of the wafer W, as indicated by reference numeral 4E in FIG. The eccentricity of the wafer W or the support substrate S can be measured satisfactorily even if the wafer W is attached to the substrate. Further, since the orientation of the wafer W can be corrected using the alignment marks M instead of the cutouts N (described later), the pre-alignment process can be performed satisfactorily.

Returning to FIG. 6, the description continues. After step S21 is performed, the determination unit 43 of the control unit 40 determines whether or not the eccentricity measured in step S21 is equal to or greater than a predetermined allowable value (step S22). If it is determined that the amount of eccentricity is equal to or greater than the predetermined allowable value (step S21: YES), the mark pre-alignment control section 45 (corresponding to the "eccentricity correction section" of the present invention) temporarily rotates the second sub-chuck 34. After releasing and moving the wafer W by the arm 31 so as to cancel out the amount of eccentricity, the wafer W is again fixed and held on the second sub-chuck 34 (step S23). If it is determined that the amount of eccentricity is less than the predetermined allowable value (step S21: NO), skip step S23 and proceed to step S24.

Subsequently, the mark pre-alignment control unit 45 detects the alignment mark M provided on the surface of the wafer W by the alignment mark detection unit 36 (corresponding to the "alignment mark detection unit" of the present invention) (step S24). .

Here, a method for detecting the alignment mark M will be described with reference to FIG. 8A and 8B are diagrams for explaining a method of detecting the alignment mark M. FIG. In the example shown in FIG. 8, it is assumed that the detection range of the alignment mark detector 36 is part of the surface of the wafer W near the outer edge.

In FIG. 8, the field of view range 361 of the alignment mark detector 36 arranged to face the surface of the wafer W is indicated by a rectangle. The alignment mark detection unit 36 uses a predetermined range within the visual field range 361 as a search range 362 for searching for the alignment mark M. FIG. At the beginning of placing the wafer W on the second sub-chuck 34, it is unknown whether the alignment mark M is within the search range 362 or not. Therefore, the mark pre-alignment control unit 45 rotates the wafer W by a predetermined angle by the second sub-chuck 34 , and compares the pre-stored image data of the alignment marks M with the search range 362 of the alignment mark detection unit 36 . Compare with image data.

Here, the predetermined angle for rotating the wafer W means that the outer edge of the wafer W is moved by a distance obtained by subtracting the sum of the size of the alignment mark M and the margin from the search range 362 (see below for the calculation formula for the movement distance). is the rotation angle required for As a result, the entire alignment mark M always falls within the search range 362 while the wafer W rotates once. For example, it can be calculated by the following formula, and for example, the predetermined angle is approximately 10°. More specifically, for example, when the diameter of the wafer W is 300 mm, the search range 362 is 20.48 mm×19.2 mm, and the size of the alignment mark M is 70 pixels×70 pixels, The predetermined angle is about 7.3°.

[Calculation formula for moving distance]
Search range - [size of alignment mark M + margin]
The mark pre-alignment control unit 45 searches the pre-stored image data of the alignment marks M and the alignment mark detection unit 36 while rotating the wafer W by a predetermined angle until the rotation angle of the wafer W reaches 360° or more. The process of matching the image data within the range 362 is repeated. Instead of rotating the wafer W by 360° or more, the mark pre-alignment control unit 45 may repeat the matching process until an image matching the stored alignment marks M is obtained. The alignment mark detection unit 36 detects the position coordinates at which an image that matches the stored alignment mark M is obtained as the position coordinates of the alignment mark M. FIG. If an image that matches the stored alignment mark M is not obtained even after rotating the wafer W by 360° or more, the mark pre-alignment control unit 45 returns the wafer W to the initial position at which the collation process was started, Predetermined error processing such as notifying the user of an error is performed.

Although the rotation direction of the wafer W is clockwise in FIG. 8, this does not mean that the rotation direction is limited. Also, the visual field range 361 of the alignment mark detection unit 36 may be the entire circumference of the wafer W. FIG.

When the alignment mark M is detected by the alignment mark detection unit 36, the mark pre-alignment control unit 45 (corresponding to the "orientation correction unit" of the present invention) determines the alignment mark M based on the position coordinates of the alignment mark M. The orientation of the wafer W is corrected by rotating the second sub-chuck 34 to the position (step S25), and the process ends.

As described above, according to the first embodiment, it is possible to correct the orientation of the wafer W based on the position of the alignment mark M indicating the orientation of the wafer W. Even a wafer W without such a notch N or a wafer W with a notch N that is difficult to detect can be satisfactorily pre-aligned.

In addition, even if the wafer W is attached on the support substrate S in a state of eccentricity from the center of the support substrate S as indicated by reference numeral 4E, the laser pre-alignment sensor 37 is used to detect the outer edge of the wafer W. Since the amount of eccentricity is measured by detecting the position of , pre-alignment processing can be performed satisfactorily.

Further, even in the case of a transparent wafer W as indicated by reference numeral 4F, for which the notch N could not be detected satisfactorily in the past, the alignment mark detector 36 detects the alignment mark M formed on the surface of the wafer W. is used to perform mark pre-alignment, so pre-alignment processing can be performed satisfactorily.

Next, the notch pre-alignment in step S15 of FIG. 5 will be described with reference to FIG. This process is performed on wafers W as indicated by reference numerals 4G and 4H in FIG.

First, when the wafer W is transferred onto the first sub-chuck 32, the standard pre-alignment control unit 44 fixes and holds the wafer W by the first sub-chuck 32 (step S30).

Subsequently, the standard pre-alignment control unit 44 rotates the first sub-chuck 32 using a rotation mechanism (not shown), and the standard pre-alignment sensor 33 detects the position coordinates of the edge of the wafer W and the position of the notch N. Measure coordinates. Further, the standard pre-alignment control unit 44 measures the eccentricity and orientation of the center of the wafer W with respect to the rotation axis of the second sub-chuck 34 based on the measured position coordinates (step S31). Here, the notch N may be detected mechanically as in the invention described in Patent Document 1, or the notch N may be detected optically as in the invention described in Patent Document 2. may

Next, the standard prealignment control unit 44 (corresponding to the "eccentricity correcting unit" of the present invention) drives the arm 31 and the first sub-chuck 32 to align the wafer W based on the measured eccentricity amount and orientation. The eccentricity and orientation are corrected (step S32), and the process ends.

Thus, in the prealignment method according to the first embodiment, it is possible to selectively perform notch prealignment and mark prealignment. Therefore, it is possible to perform the pre-alignment process satisfactorily regardless of the type or condition of the wafer W.

[Second embodiment]
Next, a pre-alignment device according to the second embodiment will be described. The pre-alignment device according to the second embodiment has a more simplified configuration than the pre-alignment device according to the first embodiment. As in the first embodiment, the prealignment apparatus according to the second embodiment not only can satisfactorily perform the prealignment process on the wafer W having the notch N in the outer peripheral edge, The pre-alignment process can be performed satisfactorily even on the wafer W without the notch N that could not be processed.

FIG. 10 is a perspective view showing a main part of an inspection device 2 to which a prealignment device according to the second embodiment is applied. As shown in FIG. 10, the inspection apparatus 2 according to the second embodiment has substantially the same configuration as the inspection apparatus 1 according to the first embodiment, but replaces the loader section 30 with a loader section 130 and controls the control section 40. The difference is that it is replaced with the part 140 .

The loader section 130 in the second embodiment has a simpler configuration than the loader section 30 in the first embodiment. Specifically, the loader section 130 does not include the second sub-chuck 34 , the ID detection section 35 and the laser pre-alignment sensor 37 . Also, the alignment mark detection section 36 (corresponding to the "alignment mark detection section" of the present invention) provided in the vicinity of the second sub-chuck 34 in the first embodiment is replaced by the first sub-chuck 32 ( (corresponding to the "sub-chuck" of the present invention).

The functional configuration of the control unit 140 will be described below with reference to FIG. 11 . As shown in FIG. 11, the controller 140 in the second embodiment has substantially the same configuration as the controller 40 in the first embodiment, but differs in the following three points. That is, the difference is that the determination unit 43 is replaced with the determination unit 143 and that the standard prealignment control unit 44 and the mark prealignment control unit 45 are replaced with the combined prealignment control unit 144 .

The determination unit 143 determines whether to perform notch prealignment or mark prealignment on the wafer W based on information preset by the user (prealignment setting information). Output.

The combined pre-alignment control unit 144 performs either notch pre-alignment or mark pre-alignment on the wafer W held on the first sub-chuck 32 based on the determination result of the determination unit 143 .

Next, a pre-alignment method according to the second embodiment will be described with reference to FIG. As shown in FIG. 12, the prealignment method according to the second embodiment is substantially the same as the prealignment method according to the first embodiment, except that steps S12 to S14 are replaced with steps S112 to S114. different. Only steps S112 to S114, which are different from the first embodiment, will be described below.

In step S112, the determination unit 143 of the control unit 140 determines whether pre-alignment for notches or pre-alignment for marks should be performed for the wafer W based on information preset by the user (pre-alignment setting information). In step S<b>113 , the arm controller 42 of the controller 140 drives the arm 31 to place the wafer W on the first sub-chuck 32 .

In step S114, the combined pre-alignment control section 144 (corresponding to the "orientation correction section" and "eccentricity correction section" of the present invention) performs mark pre-alignment in substantially the same manner as steps S20 to S25 in FIG. The difference from the first embodiment is that the eccentricity is measured using the laser pre-alignment sensor 37 in step S21 of FIG. 7 in the first embodiment, but the standard pre-alignment sensor 33 (this The difference is that the amount of eccentricity is measured using the "eccentricity measuring unit" and the "optical sensor" of the invention.

In the second embodiment, the standard pre-alignment sensor 33 is used to measure the amount of eccentricity, so unlike the first embodiment in which the laser pre-alignment sensor 37 is used, the distribution of the amount of laser light is detected linearly. Can not do it. Therefore, in the second embodiment, the pre-alignment process can be performed satisfactorily on the wafers W as indicated by reference numerals 4A to 4D in FIG. In the second embodiment, since the laser pre-alignment sensor 37 is not provided, the wafer W attached onto the support substrate S in a state of being eccentric from the center of the support substrate S as indicated by reference numeral 4E in FIG. , and a transparent wafer W as indicated by reference numeral 4F cannot be satisfactorily pre-aligned. Therefore, the prealignment apparatus according to the second embodiment is based on the premise that the support substrate S is not used or the wafer W is placed on the center of the support substrate S. Since the number of parts can be reduced, this embodiment has a large cost advantage.

As described above, as in the first embodiment, the prealignment apparatus according to the second embodiment not only can satisfactorily prealign the wafer W having the notch N in the outer edge, but also It is possible to satisfactorily perform the pre-alignment process even on the wafer W without the .

Moreover, since the second sub-chuck 34 and the laser pre-alignment sensor 37 can be omitted, the pre-alignment device according to the second embodiment can be realized at a lower cost than the first embodiment.

[Modification]
In the first and second embodiments, the determining unit 43 or 143 performs notch prealignment or mark prealignment based on information preset by the user (prealignment setting information). is determining whether However, the determination unit 43 or 143 determines which of the notch pre-alignment and the mark pre-alignment should be performed based on whether the alignment mark detection unit 36 has detected the alignment mark M on the surface of the wafer W. may be determined.

Also, in the first and second embodiments, the case where the prealignment device is applied to the inspection device is described. However, the prealignment apparatus according to the present invention can also be applied to a wafer processing apparatus for manufacturing, processing, inspecting, measuring, observing, etc. the wafer W. FIG.

[effect]
As described above, according to the prealignment apparatus according to the first and second embodiments, the alignment mark detection unit 36 detects the alignment mark M formed on the surface of the wafer W, and the alignment mark detection unit The orientation of the wafer W is corrected based on the alignment mark M detected by 36 . Accordingly, the pre-alignment process can be performed satisfactorily even for a wafer W without a notch N or a wafer W with a notch N that is difficult to detect.

According to the pre-alignment apparatus according to the first embodiment, the laser pre-alignment sensor 37 measures the eccentricity of the wafer W when the wafer W has no notch N or the wafer W has a notch N which is difficult to detect. As a result, the pre-alignment process can be favorably performed even on the wafer W to which the support substrate S is eccentrically attached.

According to the pre-alignment apparatus according to the second embodiment, when the notch N is formed in the wafer W and the notch N can be detected by the standard pre-alignment sensor 33, standard pre-alignment is performed. The eccentricity of the wafer W is measured by the sensor 33, and the orientation of the wafer is corrected based on the notch N. FIG. On the other hand, in the case of a wafer W without a notch N or a wafer W with a notch N that is difficult to detect, the standard pre-alignment sensor 33 measures the amount of eccentricity of the wafer W, and the alignment mark detector 36 detects the alignment mark M. based on the orientation of the wafer. As a result, the pre-alignment device can be realized at a lower cost than the first embodiment.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above examples, and various improvements and modifications may be made without departing from the gist of the present invention.

Reference Signs List 1, 2 Inspection device 10 Main body 20 Load port 30, 130 Loader 31 Arm 32 First sub-chuck 33 Standard pre-alignment sensor 34 Second sub-chuck 35... ID detection section, 36... alignment mark detection section, 37... laser pre-alignment sensor, 40, 140... control section, 41... body control section, 42... arm control section, 43, 143... determination section, 44... standard preset Alignment control unit 45 Mark pre-alignment control unit 361 Visual field range 362 Search range 371 Laser emitting surface 372 Laser receiving surface C Chipping N Notch M Alignment mark W …wafer

Claims (12)

A pre-alignment device for pre-aligning a wafer,
the wafer has an alignment mark indicating the orientation of the wafer;
a sub-chuck capable of holding and rotating the wafer;
an alignment mark detection unit that detects the positions of the alignment marks of the wafer held by the sub-chuck;
an orientation correction unit that corrects the orientation of the wafer by changing the rotational position of the sub-chuck based on the position of the alignment mark detected by the alignment mark detection unit;
A pre-alignment device. an eccentricity measuring unit that measures the eccentricity of the center of the wafer with respect to the center of rotation of the sub-chuck;
an eccentricity correction unit that corrects eccentricity of the wafer by changing the relative position of the wafer with respect to the sub-chuck based on the eccentricity measured by the eccentricity measurement unit;
The pre-alignment device of claim 1, comprising: The eccentricity measuring unit has a laser light projecting unit and a laser light receiving unit that receives the laser light emitted from the laser light projecting unit, and detects the wafer held by the sub-chuck. It consists of a possible laser type sensor,
The pre-alignment device according to claim 2. The eccentricity measurement unit has a non-laser light projecting unit and a non-laser light receiving unit that receives the non-laser light emitted from the non-laser light projecting unit, and the non-laser light receiving unit Consists of a total light intensity detection type optical sensor that outputs the total light intensity obtained,
The pre-alignment device according to claim 2. A pre-alignment device for pre-aligning a wafer,
the wafer has an alignment mark indicating the orientation of the wafer;
a first sub-chuck and a second sub-chuck capable of holding and rotating the wafer;
a notch detector that detects the position of the notch indicating the orientation of the wafer held by the first sub-chuck;
an alignment mark detection unit that detects the positions of the alignment marks of the wafer held by the second sub-chuck;
By changing the rotational position of the first sub-chuck or the second sub-chuck based on the position of the notch detected by the notch detector or the position of the alignment mark detected by the alignment mark detector. an orientation correction unit that corrects the orientation of the wafer;
A pre-alignment device. an eccentricity measuring unit for measuring the eccentricity of the center of the wafer with respect to the rotation center of the first sub-chuck, comprising: a non-laser light projecting unit; a first eccentricity measuring unit configured by a total light amount detection type optical sensor that outputs the total amount of light obtained by the non-laser light receiving unit;
an eccentricity measurement unit for measuring the eccentricity of the center of the wafer with respect to the center of rotation of the second sub-chuck, comprising: a laser light projecting unit; and a laser for receiving the laser light emitted from the laser light projecting unit. a second eccentricity measuring unit comprising a laser sensor capable of detecting the wafer held by the second sub-chuck, and a light receiving unit;
By changing the relative position of the wafer with respect to the first sub-chuck or the second sub-chuck based on the eccentricity measured by the first eccentricity measuring unit or the second eccentricity measuring unit an eccentricity correction unit that performs eccentricity correction;
6. The pre-alignment device of claim 5, comprising: A pre-alignment method for pre-aligning a wafer, comprising:
the wafer has an alignment mark indicating the orientation of the wafer;
an alignment mark detection step of detecting the positions of the alignment marks of the wafer held by a rotatable sub-chuck that holds the wafer;
an orientation correction step of correcting the orientation of the wafer by changing the rotational position of the sub-chuck based on the position of the alignment mark detected in the alignment mark detection step;
A pre-alignment method, comprising: an eccentricity measuring step of measuring the eccentricity of the center of the wafer with respect to the center of rotation of the sub-chuck;
an eccentricity correction step of correcting eccentricity of the wafer by changing the relative position of the wafer with respect to the sub-chuck based on the eccentricity measured in the eccentricity measurement step;
The pre-alignment method according to claim 7, comprising: The eccentricity measuring step includes a laser light projecting section and a laser light receiving section for receiving the laser light emitted from the laser light projecting section, and detects the wafer held by the sub-chuck. possible using a laser-based sensor,
The pre-alignment method according to claim 8. The eccentricity measuring step includes a non-laser light projecting section and a non-laser light receiving section that receives the non-laser light emitted from the non-laser light projecting section, and the non-laser light receiving section Performed using a total light intensity detection type optical sensor that outputs the total light intensity obtained,
The pre-alignment method according to claim 8. A pre-alignment method for pre-aligning a wafer, comprising:
the wafer has an alignment mark indicating the orientation of the wafer;
a notch detection step of detecting the position of a notch indicating the orientation of the wafer held by a first sub-chuck capable of holding and rotating the wafer; a detection step of selectively performing an alignment mark detection step of detecting the positions of the alignment marks of the held wafer;
An orientation correction step of correcting the orientation of the wafer by changing the rotational position of the first sub-chuck or the second sub-chuck based on the position of the notch or the position of the alignment mark detected in the detection step. and,
A pre-alignment method, comprising: an eccentricity measuring step of measuring the eccentricity of the center of the wafer with respect to the center of rotation of the first sub-chuck, wherein a non-laser light receiving portion for receiving light, and a first eccentricity measuring step performed using a total light amount detection type optical sensor for outputting the total light amount obtained by the non-laser light receiving portion; an eccentricity measuring step of measuring the eccentricity of the center of the wafer with respect to the center of rotation of the second sub-chuck, comprising: a laser light projecting unit; and a laser beam receiving the laser light emitted from the laser light projecting unit. a second eccentricity measuring step that selectively performs a second eccentricity measuring step that is performed using a laser sensor capable of detecting the wafer;
an eccentricity correction step of correcting the eccentricity of the wafer by changing the relative position of the wafer with respect to the first sub-chuck or the second sub-chuck based on the eccentricity measured in the eccentricity measurement step;
The pre-alignment method according to claim 11, comprising:

Images