Pre-alignment device and method

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

[Technical Field]

[0001] 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-aligning a wafer that does not have a notch or whose notch is difficult to detect. [Background technology]

[0002] In the semiconductor manufacturing process, wafers are inspected while placed on the stage of an inspection device. To inspect a wafer with high accuracy, it is necessary to perform a pre-alignment process so that the wafer is oriented in a specific direction relative to the stage before placing it on the stage.

[0003] Therefore, various pre-alignment processing techniques have been proposed. For example, Patent Document 1 describes a substrate positioning system that adjusts the orientation of a substrate that has a notch on its periphery that indicates the orientation of the substrate. This substrate positioning system includes a contact member that contacts the edge of the notch, a moving unit that moves the contact member around a predetermined center of rotation, and a positioning device that determines the position of the periphery of the substrate so that the center of the substrate coincides with the center of rotation. After the center of the substrate is aligned with the center of rotation using the determining device, the contact portion of the contact member is brought into contact with the notch in the substrate, and the contact member is moved in an arc to rotate the wafer and adjust its orientation.

[0004] Furthermore, Patent Document 2 describes a technology in which three line sensors are used to detect the position coordinates of three points on the edge of a wafer and the position coordinates of a notch, and the center position and orientation of the wafer are detected based on the detection results. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. WO2005 / 055315 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-253197 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the techniques described in Patent Documents 1 and 2 are based on the premise that a notch is formed in the wafer, and therefore there is a problem in that the pre-alignment process cannot be performed well in the case of a wafer without a notch.

[0007] Furthermore, in the semiconductor manufacturing process, chipping can occur on the wafer during processing, causing the notched portion of the wafer to break off or making it difficult to detect the notch. In such cases, there is a risk that the notch cannot be detected properly, making it impossible to accurately correct the orientation of the wafer.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a pre-alignment device and method that can perform good pre-alignment processing even when no notch is formed in the wafer or when it is difficult to detect the notch. [Means for solving the problem]

[0009] In order to solve the above problems, a pre-alignment device according to a first aspect of the present invention is a pre-alignment device that pre-aligns a wafer having an alignment mark that indicates the orientation of the wafer, and includes a sub-chuck that can hold the wafer and rotate, an alignment mark detection unit that detects the position of the alignment mark of the wafer held by the sub-chuck, and 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.

[0010] A pre-alignment apparatus according to a second aspect of the present invention is the pre-alignment apparatus of the first aspect, further comprising: an eccentricity measuring unit that measures an eccentricity of the center of the wafer relative to the center of rotation of the sub-chuck; and 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 measuring unit.

[0011] A pre-alignment device according to a third aspect of the present invention is the pre-alignment device of the second aspect, wherein the eccentricity measuring unit has a laser light projecting unit and a laser light receiving unit that receives the laser light irradiated from the laser light projecting unit, and is configured by a laser sensor that can detect the wafer held by the sub-chuck.

[0012] A pre-alignment device according to a fourth aspect of the present invention is the second aspect, wherein the eccentricity measuring unit has a non-laser light projecting unit and a non-laser light receiving unit that receives the non-laser light irradiated from the non-laser light projecting unit, and is configured by a total light amount detection type optical sensor that outputs the total light amount obtained by the non-laser light receiving unit.

[0013] In order to solve the above problems, a pre-alignment apparatus according to a fifth aspect of the present invention is a pre-alignment apparatus that pre-aligns a wafer having an alignment mark that indicates the orientation of the wafer, and includes a first sub-chuck and a second sub-chuck that can hold the wafer and rotate, a notch detection unit that detects the position of a notch that indicates the orientation of the wafer held by the first sub-chuck, an alignment mark detection unit that detects the position of the alignment mark of the wafer held by the second sub-chuck, and an orientation correction unit that corrects 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 detected by the notch detection unit or the position of the alignment mark detected by the alignment mark detection unit.

[0014] A pre-alignment device according to a sixth aspect of the present invention is the pre-alignment device of the fifth aspect, further comprising: an eccentricity measuring unit that measures the eccentricity of the center of the wafer relative to the rotation center of the first sub-chuck, the first eccentricity measuring unit having a non-laser light projector and a non-laser light receiving unit that receives non-laser light irradiated from the non-laser light projector and configured with a total light amount detection type optical sensor that outputs the total light amount obtained by the non-laser light receiving unit; an eccentricity measuring unit that measures the eccentricity of the center of the wafer relative to the rotation center of the second sub-chuck, the second eccentricity measuring unit having a laser light projector and a laser light receiving unit that receives laser light irradiated from the laser light receiving unit and configured with a laser type sensor that can detect the wafer held by the second sub-chuck; and 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 measured by the first eccentricity measuring unit or the second eccentricity measuring unit.

[0015] In order to solve the above problems, a pre-alignment method according to a seventh aspect of the present invention is a pre-alignment method for pre-aligning a wafer having an alignment mark that indicates the orientation of the wafer, and includes an alignment mark detection step of detecting the position of the alignment mark of a wafer held by a rotatable sub-chuck that holds the wafer, and 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.

[0016] A pre-alignment method according to an eighth aspect of the present invention is the same as that of the seventh aspect, and further comprises an eccentricity measuring step of measuring an eccentricity of the center of the wafer relative to the center of rotation of the sub-chuck, and an eccentricity correcting step of correcting the 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 measuring step.

[0017] A pre-alignment method according to a ninth aspect of the present invention is the eighth aspect, wherein the eccentricity measuring step is performed using a laser sensor that has a laser beam projector and a laser beam receiver that receives the laser beam irradiated from the laser beam projector and is capable of detecting the wafer held by the sub-chuck.

[0018] A pre-alignment method according to a tenth aspect of the present invention is the eighth aspect, wherein the eccentricity measuring step is performed using a total light amount detection optical sensor that has a non-laser light projecting unit and a non-laser light receiving unit that receives the non-laser light irradiated from the non-laser light projecting unit, and outputs the total light amount obtained by the non-laser light receiving unit.

[0019] In order to solve the above-mentioned problems, a pre-alignment method according to an eleventh aspect of the present invention is a pre-alignment method for pre-aligning a wafer having an alignment mark that indicates the orientation of the wafer, and includes a detection step that selectively performs a notch detection step of detecting the position of a notch that indicates the orientation of a wafer held by a rotatable first sub-chuck that holds the wafer, and an alignment mark detection step of detecting the position of an alignment mark of a wafer held by a rotatable second sub-chuck that holds the wafer, and 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.

[0020] A pre-alignment method according to a twelfth aspect of the present invention, in the eleventh aspect, comprises: an eccentricity measuring step of selectively performing an eccentricity measuring step of measuring an eccentricity of the center of the wafer relative to the rotation center of the first sub-chuck, the first eccentricity measuring step being performed using a total light amount detection type optical sensor having a non-laser light projector and a non-laser light receiving unit that receives non-laser light irradiated from the non-laser light projector and that outputs a total light amount obtained by the non-laser light receiving unit; and a second eccentricity measuring step of measuring an eccentricity of the center of the wafer relative to the rotation center of the second sub-chuck, the second eccentricity measuring step being performed using a laser type sensor that has a laser light projector and a laser light receiving unit that receives laser light irradiated from the laser light projector and that can detect the wafer; and an eccentricity correcting step of correcting 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 measuring step. [Effects of the Invention]

[0021] According to the present invention, even when no notch is formed on the wafer or when it is difficult to detect the notch, it is possible to perform a good pre-alignment process. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a perspective view showing a main part of an inspection device to which the pre-alignment device according to the first embodiment is applied. [Figure 2] FIG. 2 is an enlarged perspective view of the vicinity of a second sub-chuck. [Figure 3] FIG. 2 is a functional block diagram of a control unit in the first embodiment. [Figure 4] 3A to 3C are diagrams showing examples of wafers that can be well pre-aligned in the first embodiment. [Figure 5] 4 is a flowchart showing an example of a pre-alignment method according to the first embodiment. [Figure 6]5 is a flowchart showing an example of mark pre-alignment in the pre-alignment method according to the first embodiment. [Figure 7] 10A and 10B are diagrams illustrating eccentricity correction using a laser pre-alignment sensor. [Figure 8] 3A and 3B are diagrams illustrating detection of alignment marks by an alignment mark detection unit. [Figure 9] 5 is a flowchart showing an example of pre-alignment for a notch in the pre-alignment method according to the first embodiment. [Figure 10] FIG. 10 is a perspective view showing a main part of an inspection device to which a pre-alignment device according to a second embodiment is applied. [Figure 11] FIG. 10 is a functional block diagram of a control unit in the second embodiment. [Figure 12] 10 is a flowchart showing an example of a pre-alignment method according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pre-alignment apparatus and method according to an embodiment of the present invention will now be described with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same components and steps, and the description thereof will be omitted.

[0024] [First embodiment] Fig. 1 is a perspective view showing a main part of an inspection apparatus (prober) 1 to which a pre-alignment apparatus according to a first embodiment is applied. Fig. 2 is an enlarged perspective view of the vicinity of a second sub-chuck. In Figs. 1 and 2, the direction parallel to the stage 11, the first sub-chuck 32, and the second sub-chuck 34 (surface of the wafer W) is the X direction, and the Y direction perpendicular to the X direction is the Z direction.

[0025] The pre-alignment device according to the first embodiment can not only satisfactorily pre-align a wafer W having a notch N on its outer edge, as in the conventional case, but also satisfactorily pre-align a wafer W having no notch N, which could not be pre-aligned in the conventional case. The wafer W will be described in detail later.

[0026] As shown in Fig. 1, the inspection device 1 includes a main body 10, a load port 20, a loader 30, and a control unit 40 (see Fig. 3). The loader 30 corresponds to the pre-alignment 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).

[0027] The main chuck is mounted on the stage 11 and securely holds the wafer W. The probe card has multiple 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), the main body 10 fixes the wafer W placed on the stage 11 with the main chuck, and the test head supplies power and electrical signals to each chip via the probe needles of the probe card while the probe needles are in contact with the electrodes of each chip formed on the wafer W. Furthermore, the test head transmits response signals from each chip to the tester main body, which analyzes the response signals to inspect the electrical characteristics of each chip. The main chuck is, for example, a vacuum chuck or an electrostatic chuck. The main body 10 has a known configuration, and therefore a detailed description thereof will be omitted.

[0028] The load port section 20 includes a storage section (not shown) therein for storing the wafers W. The wafers W are carried out from the load port section 20 to the loader section 30 by an arm 31 of the loader section 30.

[0029] The loader unit 30 performs pre-alignment on the wafer W and places the wafer W at a predetermined position on the stage 11 in a predetermined orientation relative to the stage 11. The loader unit 30 includes an arm 31, a first sub-chuck 32, a standard pre-alignment sensor 33, a second sub-chuck 34, an ID detection unit 35, an alignment mark detection unit 36, and a laser pre-alignment sensor 37.

[0030] The arm 31 is movable in any of the X, Y, and Z directions by a drive unit (not shown), and transports the wafer W between the load port unit 20 and the stage 11 of the main body unit 10 via the loader unit 30. The transport arm 31 also changes the relative position of the wafer W with respect to the first sub-chuck 32 or the second sub-chuck 34 in order to correct eccentricity of the wafer W with respect to the rotation axis (center of rotation) of the first sub-chuck 32 or the second sub-chuck 34.

[0031] The first sub-chuck 32 corresponds to the "first sub-chuck" of the present invention and holds the wafer W transferred by the arm 31. The first sub-chuck 32 can be rotated by a rotation mechanism (not shown). The first sub-chuck 32 is, for example, a vacuum chuck or an electrostatic chuck.

[0032] The standard pre-alignment sensor 33 is provided, for example, near the first sub-chuck 32. The standard pre-alignment sensor 33 corresponds to the "eccentricity measuring unit" and the "optical sensor" of the present invention, and measures the eccentricity of the center of the wafer W with respect to the center of rotation of the first sub-chuck 32, for the wafer W held by the first sub-chuck 32, and detects the notch N formed in the wafer W. Details of the standard pre-alignment sensor 33 will be described later.

[0033] 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. The second sub-chuck 34 can be rotated by a rotation mechanism (not shown).

[0034] 1 and 2, an ID detection unit 35, an alignment mark detection unit 36, and a laser pre-alignment sensor 37 are provided near the second sub-chuck 34. The ID detection unit 35 detects wafer identification information (wafer ID) formed on the surface of the wafer W. 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.

[0035] The alignment mark detection unit 36 ​​corresponds to the "alignment mark detection unit" of the present invention, is disposed opposite the surface of the wafer W held by the second sub-chuck 34, and detects alignment marks M formed on the surface of the wafer W held by the second sub-chuck 34. The alignment marks M will be described later. Like the ID detection unit 35, the alignment mark detection unit 36 ​​is one of various cameras such as a CCD (Charge Coupled Device) camera or a CMOS (Complementary Metal Oxide Semiconductor) camera. Although the ID detection unit 35 and the alignment mark detection unit 36 ​​are shown as separate entities in FIGS. 1 and 2, the alignment mark detection unit 36 ​​may also serve as the ID detection unit 35.

[0036] The laser pre-alignment sensor 37 corresponds to the "eccentricity measuring unit" and "laser sensor" of the present invention, and measures the eccentricity of the center of the wafer W held by the second sub-chuck 34 relative to the center of rotation of the second sub-chuck 34. Specifically, the laser pre-alignment sensor 37 acquires the coordinates of the outer edge (edge) of the wafer W by irradiating a laser beam (parallel beam) near the outer edge of the wafer W substantially perpendicular to the surface of the wafer W. 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 eccentricity of the center of the wafer W relative to the center of rotation of the second sub-chuck 34. The laser pre-alignment sensor 37 will be described in detail later.

[0037] The control unit 40 controls the probe test of the wafer W in the main body unit 10 and the transport and pre-alignment of the wafer W in the loader unit 30 based on a predetermined operation program.

[0038] The functional configuration of the control unit 40 will be described below with reference to Fig. 3. The control unit 40 comprehensively controls the various devices that make up the inspection apparatus 1. The control unit 40 includes a main body control unit 41, an arm control unit 42, a determination unit 43, a standard pre-alignment control unit 44, a mark pre-alignment control unit 45, and an input / output unit 47.

[0039] The main body control unit 41 controls the inspection of the wafer W on the stage 11 by the main body unit 10 .

[0040] The arm control unit 42 controls the operation of the arm 31. Specifically, the arm control unit 42 controls the arm 31 so as to take out the wafer W from the load port unit 20, hold the wafer W on the first sub-chuck 32 or the second sub-chuck 34 based on the determination result by the determination unit 43, and unload the wafer W after pre-alignment onto the stage 11.

[0041] The determination unit 43 determines whether notch pre-alignment or mark pre-alignment should be performed on the wafer W based on the pre-alignment setting information described later, and outputs the determination result to the arm control unit 42, the standard pre-alignment control unit 44, and the mark pre-alignment control unit 45.

[0042] The standard pre-alignment control unit 44 controls the pre-alignment of the wafer W by the standard pre-alignment sensor 33. The mark pre-alignment control unit 45 controls the pre-alignment of the wafer W by the alignment mark detection unit 36 ​​and the laser pre-alignment sensor 37.

[0043] The input / output unit 47 is an interface for inputting and 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. 1, this is not intended to limit the input / output unit 47. Furthermore, 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.

[0044] The main body control unit 41, arm control unit 42, determination unit 43, standard pre-alignment control unit 44, and mark pre-alignment control unit 45 that constitute the control unit 40 are realized by, for example, one or more personal computers, workstations, PLCs (Programmable Logic Controllers), etc. The control unit 40 also includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a storage device (not shown) that stores a control program (for example, an HDD (Hard Disk Drive) or an SSD (Solid State Drive)), and an SDRAM (Synchronous Dynamic Random Access Memory) that can be used as a working area for the CPU.

[0045] Next, a wafer W that can be well pre-aligned by the pre-alignment device according to the first embodiment will be described with reference to Fig. 4. In Fig. 4, reference numerals 4G and 4H indicate examples of wafers W that can be well pre-aligned by pre-alignment of the wafer W (notch pre-alignment) by the standard pre-alignment sensor 33.

[0046] 4 indicates a wafer W having a notch N formed on its outer edge. The notch N is formed to indicate the orientation of the wafer W, and is a partial notch on the outer periphery formed by uniformly cutting away part of the outer edge of the wafer W from one side to the other side of the wafer W in the thickness direction of the wafer W.

[0047] In addition, reference numerals 4G and others in FIG. 4 show an example in which the notch N is a V-shaped notch. However, the shape of the notch N is not limited to this example, and may be any shape, such as an orientation flat or a U-shape. In the case of the wafer W shown by reference numeral 4G, a pre-alignment process is performed based on the notch. Examples of materials for the wafer W include glass and silicon.

[0048] The reference symbol 4H in FIG. 4 indicates a wafer W in which the wafer W is attached to a support substrate S with the support substrate S and the wafer being properly aligned relative to each other so that the center of the support substrate S and the center of the wafer W coincide with each other, and a notch N is formed. For example, in a semiconductor manufacturing process, after a pattern is formed on the front surface of the wafer W, a back-grinding process may be performed in which the entire back surface of the wafer W is ground to reduce its thickness. When the wafer W becomes thin, it becomes prone to bending, which may make it difficult to transport the wafer W alone. In this case, a support substrate S is attached to the back surface of the wafer W using tape, an adhesive, or the like, and then transported. Various types of glass, such as quartz glass, borosilicate glass, and alkali-free glass, are preferably used as the support substrate S.

[0049] If the relative positions of the support substrate S and the wafer W are well aligned as shown by symbol 4H in Figure 4, the notch pre-alignment allows for good pre-alignment processing of the wafer W.

[0050] 4, reference numerals 4A to 4F indicate examples of wafers W for which good pre-alignment processing can be performed by pre-alignment of the wafer W (mark pre-alignment) by the alignment mark detection unit 36. All of the wafers W indicated by reference numerals 4A to 4E indicate examples that are difficult to detect by the notch pre-alignment described above.

[0051] In the first embodiment (as well as the second embodiment described below), even if no notch N is formed in the wafer W or if it is difficult to detect the notch N, the wafer W has an alignment mark M formed on either the front or back surface of the wafer W (in this example, on the front surface of the wafer W) to indicate the orientation of the wafer W (see FIG. 8). The alignment mark M is a flat mark or a very shallow imprint having any shape and color that can be detected by the alignment mark detection unit 35. The alignment mark M differs from the notch N in that it does not affect the shape of the outer periphery.

[0052] 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 may be any shape such as a part of a wafer ID attached to the surface of the wafer W.

[0053] The alignment mark M is formed as needed, for example, by a user of the inspection device 1 using any known technique. The alignment mark M is formed at a predetermined position on the wafer W so that it can be detected by the alignment mark detection unit 35. 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 detection unit 36.

[0054] 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 a notch N and chipping C are mixed on the outer edge (hereinafter referred to as a wafer with a notch N that is difficult to detect).

[0055] For example, even if a notch N is formed in the outer edge portion, chipping C may occur in the outer edge portion of the wafer W during processing of the wafer W. In such a case, the notch N and the chipping C are mixed together, making it difficult to detect the notch N, and therefore making it difficult to perform pre-alignment processing using notch pre-alignment.

[0056] In the first embodiment, for wafers W such as those shown by the reference numerals 4A and 4B, pre-alignment for marks, rather than pre-alignment for notches, can be performed to enable good pre-alignment processing.

[0057] Reference numeral 4C denotes an example of a wafer W without a notch N to which a support substrate S is attached. Reference numeral 4D denotes an example of a wafer W with a notch N that is difficult to detect to which a support substrate S is attached. In the first embodiment, as shown by reference numerals 4C and 4D, even for a wafer W to which a support substrate S is attached, a good pre-alignment process can be performed by mark pre-alignment.

[0058] Reference numeral 4E denotes an example of a wafer W without a notch N that is attached to the support substrate S in a state where it is eccentric from the center of the support substrate S. In the first embodiment, eccentricity correction is performed using the laser pre-alignment sensor 37, so that even for the wafer W that is attached to the support substrate S in a state where it is eccentric from the center of the support substrate S, it is possible to perform a good pre-alignment process by the mark pre-alignment.

[0059] Reference symbol 4F indicates an example of a transparent wafer W having a notch N formed therein. The invention described in Patent Document 2, which uses a line sensor, is unable to properly detect the notch N formed in the transparent wafer W, and therefore is unable to perform a proper pre-alignment process. However, in the first embodiment, alignment marks M formed on the surface of the transparent wafer W are detected using the alignment mark detection unit 36 ​​to perform mark pre-alignment, and therefore, a proper pre-alignment process can be performed.

[0060] Next, the pre-alignment method according to the first embodiment will be described with reference to Fig. 5 to Fig. 9. First, the main processing flow of the pre-alignment method according to the first embodiment will be described with reference to Fig. 5.

[0061] First, the arm control unit 42 of the control unit 40 causes the arm 31 to remove the wafer W from the load port unit 20 (step S10). Subsequently, the determination unit 43 of the control unit 40 determines the pre-alignment process to be performed on the wafer W removed in step S10 (step S12).

[0062] Specifically, before starting inspection of the wafer W, the user sets whether to perform standard pre-alignment or mark pre-alignment. The user may set the alignment process, for example, on a wafer lot basis, or may set it individually for each wafer W. Then, the determination unit 43 determines the pre-alignment process to be performed on the wafer W by determining the sub-chuck to which the wafer W removed in step S10 is to be transferred based on the information set by the user (pre-alignment setting information).

[0063] Based on the determination result in step S12, the arm control unit 42 transfers the wafer W to either the first sub-chuck 32 or the second sub-chuck 34 (step S13). Subsequently, based on the determination result in step S12, mark pre-alignment (step S14) or notch pre-alignment (step S15) is performed. Steps S14 and S15 will be described in detail 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.

[0064] Next, the mark pre-alignment in step S14 of Fig. 5 will be described in detail with reference to Fig. 6. This process is performed on a wafer W as shown by reference numerals 4A to 4F in Fig. 4. First, when the wafer W is transferred onto the second sub-chuck 34, the mark pre-alignment control unit 45 causes the second sub-chuck 34 to fix and hold the wafer W (step S20). Next, while rotating the second sub-chuck 34 with a rotation mechanism (not shown), the laser pre-alignment sensor 37 measures the coordinates of the outer edge of the wafer W to measure the amount of positional deviation of the center of the wafer W with respect to the rotation axis of the second sub-chuck 34 (i.e., the amount of eccentricity with respect to the rotation axis) (step S21).

[0065] Hereinafter, eccentricity correction using the laser pre-alignment sensor 37 will be described with reference to FIG. 7. As shown in FIG. 7, the laser pre-alignment sensor 37 has a laser emitting surface (laser light projecting unit) 371 on one side (the upper side in FIG. 7) of the flat wafer W and a laser receiving surface (laser light receiving unit) 372 on the other side (the lower side in FIG. 7) of the wafer W, and is configured as a laser sensor capable of detecting the wafer W held by the second sub-chuck 34, for example, the outer edge of the wafer W. As the laser pre-alignment sensor 37, for example, a laser length measuring sensor (model: ZX-GT) manufactured by Omron Corporation can be used. The laser pre-alignment sensor 37 is an example of a "laser sensor" that constitutes the "eccentricity measuring unit" and the "second eccentricity measuring unit" of the present invention.

[0066] The laser emitting surface 371 of the laser pre-alignment sensor 37 irradiates a laser beam having a width along the radial direction of the wafer W from one side of the wafer W in a direction approximately perpendicular to the surface of the wafer W. The laser receiving surface 372 of the laser pre-alignment sensor 37 receives the laser beam and measures the amount of laser beam. This allows the distribution of the amount of laser beam in the radial direction of the wafer W to be obtained. Because the laser beam is reflected or blocked by the outer edge of the wafer W, the position of the outer edge of the wafer W is observed as a position where the amount of light changes locally in a step-like manner in the distribution of the amount of laser beam in the radial direction of the wafer W. Therefore, the position coordinates of the outer edge of the wafer W can be measured using the laser pre-alignment sensor 37.

[0067] By performing this measurement over the entire circumference of the wafer W (360°), the mark pre-alignment control unit 45 can measure the position coordinates of the outer edge of the wafer W over the entire circumference of the wafer W. Then, the mark pre-alignment control unit 45 measures the amount of positional deviation of the center of the wafer W from the rotation axis of the second sub-chuck 34 (i.e., the amount of eccentricity with respect to the rotation axis) from the change in the position coordinates of the outer edge over the entire circumference of the wafer W. Note that the method for calculating this amount of eccentricity is self-evident, and therefore a detailed explanation will be omitted.

[0068] On the other hand, a total light amount detection type optical sensor is used for the standard pre-alignment sensor 33. As described above, this total light amount detection type optical sensor (i.e., the standard pre-alignment sensor 33) is used to measure the eccentricity of the center of the wafer W relative to the rotation center of the first sub-chuck 32 and to detect the notch N formed in the wafer W. It is possible to irradiate the outer edge (edge) of the wafer W with measurement light (non-laser light) from a measurement light irradiation surface (non-laser light projecting portion) on one side, and detect the total amount of light with a 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 when the wafer W is rotated, and therefore the total amount of light detected by the total light amount detection type sensor does not change.

[0069] If the wafer W is eccentric, rotating the wafer W moves the outer edge of the wafer W, causing the detected value of the total light amount to change sinusoidally. Therefore, the phase of this sinusoidal wave can be detected as the eccentricity angle, and the amplitude can be detected as the eccentricity distance. However, if 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 the total light amount detected by a total light amount detection optical sensor hardly changes. For this reason, a total light amount detection optical sensor (i.e., the standard pre-alignment sensor 33) may not be able to measure the eccentricity of the wafer W depending on the type of wafer W. Similarly, if the wafer W is attached to a transparent support substrate S, it may not be able to measure the eccentricity of the wafer W. The standard pre-alignment sensor 33 is an example of an "optical sensor" constituting the "eccentricity measurement unit" and "first eccentricity measurement unit" of the present invention.

[0070] In contrast, the laser pre-alignment sensor 37 employed in the first embodiment can linearly detect the distribution of the amount of laser light in addition to the total amount of laser light by the above-mentioned method. In the laser pre-alignment sensor 37, the amount of laser light locally decreases at the position of the outer edge (edge) of the wafer W, so the position on the detection line where the amount of laser light decreases can be detected as the position of the outer edge (edge) of the wafer W.

[0071] By detecting this outer edge over the entire 360° circumference of the wafer W, it is possible to satisfactorily measure the eccentricity of the wafer W or the support substrate S, even if the wafer W is transparent or the wafer W is attached to the support substrate S in a state where it is eccentric from the center of the transparent support substrate S, as shown by reference numeral 4E in Fig. 4. Furthermore, since the orientation of the wafer W can be corrected using the alignment mark M instead of the notch N (described later), the pre-alignment process can be performed satisfactorily.

[0072] 6, the explanation will be continued. After step S21 is performed, the determination unit 43 of the control unit 40 determines whether the eccentricity measured in step S21 is equal to or greater than a predetermined tolerance (step S22). If it is determined that the eccentricity is equal to or greater than the predetermined tolerance (step S21: YES), the mark pre-alignment control unit 45 (corresponding to the "eccentricity correction unit" of the present invention) temporarily releases the second sub-chuck 34, moves the wafer W by the arm 31 so as to cancel out the eccentricity, and then fixes and holds the wafer W on the second sub-chuck 34 again (step S23). If it is determined that the eccentricity is less than the predetermined tolerance (step S21: NO), step S23 is omitted and the process proceeds to step S24.

[0073] Next, the mark pre-alignment control unit 45 detects the alignment marks 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).

[0074] Here, a method for detecting the alignment mark M will be described with reference to Fig. 8. Fig. 8 is a diagram for explaining the method for detecting the alignment mark M. In the example shown in Fig. 8, it is assumed that the detection range of the alignment mark detection unit 36 ​​is a part of the surface near the outer edge of the wafer W.

[0075] 8, the field of view 361 of the alignment mark detection unit 36 ​​disposed opposite the surface of the wafer W is indicated by a rectangle. The alignment mark detection unit 36 ​​sets a predetermined range within the field of view 361 as a search range 362 in which it searches for the alignment mark M. When the wafer W is initially placed on the second sub-chuck 34, it is unknown whether the alignment mark M is within the search range 362. Therefore, the mark pre-alignment control unit 45 compares pre-stored image data of the alignment mark M with image data within the search range 362 of the alignment mark detection unit 36 ​​while rotating the wafer W by a predetermined angle using the second sub-chuck 34.

[0076] Here, the predetermined angle for rotating the wafer W is the rotation angle required to move the outer edge of the wafer W by the 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). This ensures that the entire alignment mark M falls within the search range 362 during one rotation of the wafer W. For example, this can be calculated using the following formula, and the predetermined angle is, for example, approximately 10°. More specifically, for example, if 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 approximately 7.3°.

[0077] [Travel distance calculation formula] Search range - [Alignment mark M size + margin] The mark pre-alignment control unit 45 repeats the process of comparing the pre-stored image data of the alignment mark M with the image data within the search range 362 of the alignment mark detection unit 36 ​​while rotating the wafer W by a predetermined angle at a time until the rotation angle of the wafer W reaches 360° or more. Instead of rotating the wafer W by 360° or more, the mark pre-alignment control unit 45 may repeat the comparison process until an image matching the stored alignment mark M is obtained. The alignment mark detection unit 36 ​​detects the position coordinates at which an image matching the stored alignment mark M is obtained as the position coordinates of the alignment mark M. If an image matching 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 the start of the comparison process and performs a predetermined error process, such as notifying the user of an error.

[0078] 8, the rotation direction of the wafer W is clockwise, but this is not intended to limit the rotation direction. Also, the field of view 361 of the alignment mark detection unit 36 ​​may be the entire circumference of the wafer W.

[0079] 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) corrects the orientation of the wafer W by rotating the second sub-chuck 34 based on the position coordinates of the alignment mark M so that the alignment mark M is in a predetermined position (step S25), and then the processing is completed.

[0080] 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, and therefore, pre-alignment processing can be performed satisfactorily even for a wafer W that does not have a notch N as shown by symbols 4A to 4D in FIG. 4 or a wafer W that has a notch N that is difficult to detect.

[0081] Furthermore, even in the case of a wafer W attached to a support substrate S in a state where it is eccentric from the center of the support substrate S, as shown by the symbol 4E, the amount of eccentricity is measured by detecting the position of the outer edge (edge) of the wafer W using the laser pre-alignment sensor 37, so that the pre-alignment process can be performed satisfactorily.

[0082] Furthermore, even in the case of a transparent wafer W such as that shown by symbol 4F, in which it was previously not possible to detect notches N properly, the alignment mark M formed on the surface of the wafer W is detected using the alignment mark detection unit 36 ​​to perform mark pre-alignment, so that pre-alignment processing can be performed properly.

[0083] Next, the notch pre-alignment in step S15 in Fig. 5 will be described with reference to Fig. 9. This process is performed on a wafer W as shown by reference numerals 4G and 4H in Fig. 4.

[0084] First, when the wafer W is transferred onto the first sub-chuck 32, the standard pre-alignment control unit 44 causes the first sub-chuck 32 to fix and hold the wafer W (step S30).

[0085] Next, the standard pre-alignment control unit 44 rotates the first sub-chuck 32 using a rotation mechanism (not shown) while measuring the position coordinates of the outer edge of the wafer W and the position coordinates of the notch N using the standard pre-alignment sensor 33. Furthermore, the standard pre-alignment control unit 44 measures the amount of eccentricity and direction of the center of the wafer W relative 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 may be detected optically as in the invention described in Patent Document 2.

[0086] Next, the standard pre-alignment control unit 44 (corresponding to the "eccentricity correction unit" of the present invention) drives the arm 31 and the first sub-chuck 32 to correct the eccentricity and orientation of the wafer W based on the measured eccentricity amount and orientation (step S32), and then ends the process.

[0087] In this way, the pre-alignment method according to the first embodiment allows selective execution of notch pre-alignment and mark pre-alignment, thereby enabling good pre-alignment processing regardless of the type or condition of the wafer W.

[0088] [Second embodiment] Next, a pre-alignment apparatus according to a second embodiment will be described. The pre-alignment apparatus according to the second embodiment has a simpler configuration than the pre-alignment apparatus according to the first embodiment. Like the first embodiment, the pre-alignment apparatus according to the second embodiment is not only capable of performing a satisfactory pre-alignment process on a wafer W having a notch N on its outer periphery, but also capable of performing a satisfactory pre-alignment process on a wafer W without a notch N, which was previously not possible to perform a pre-alignment process on.

[0089] Fig. 10 is a perspective view showing the main parts of an inspection device 2 to which the pre-alignment device according to the second embodiment is applied. As shown in Fig. 10, the inspection device 2 according to the second embodiment has almost the same configuration as the inspection device 1 according to the first embodiment, but differs in that the loader unit 30 is replaced with a loader unit 130 and the control unit 40 is replaced with a control unit 140.

[0090] In the second embodiment, the loader unit 130 has a simpler configuration than the loader unit 30 in the first embodiment. Specifically, the loader unit 130 does not include the second sub-chuck 34, the ID detection unit 35, or the laser pre-alignment sensor 37. In addition, the alignment mark detection unit 36 ​​(corresponding to the "alignment mark detection unit" of the present invention) that was provided near the second sub-chuck 34 in the first embodiment is provided near the first sub-chuck 32 (corresponding to the "sub-chuck" of the present invention) in the second embodiment.

[0091] The functional configuration of the control unit 140 will be described below with reference to Fig. 11. As shown in Fig. 11, the control unit 140 in the second embodiment has almost the same configuration as the control unit 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 a determination unit 143, and that the standard pre-alignment control unit 44 and the mark pre-alignment control unit 45 are replaced with a dual-purpose pre-alignment control unit 144.

[0092] The determining unit 143 determines whether notch pre-alignment or mark pre-alignment is to be performed on the wafer W based on information (pre-alignment setting information) preset by the user, and outputs the result to the dual-purpose pre-alignment control unit 144.

[0093] The dual-purpose 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 by the determination unit 143 .

[0094] Next, a pre-alignment method according to the second embodiment will be described with reference to Fig. 12. As shown in Fig. 12, the pre-alignment method according to the second embodiment is almost the same as the pre-alignment method according to the first embodiment, except that steps S12 to S14 are replaced with steps S112 to S114. Only steps S112 to S114, which are different from the first embodiment, will be described below.

[0095] In step S112, the determination unit 143 of the control unit 140 determines, based on information preset by the user (pre-alignment setting information), whether notch pre-alignment or mark pre-alignment should be performed on the wafer W. In step S113, the arm control unit 42 of the control unit 140 drives the arm 31 to place the wafer W on the first sub-chuck 32.

[0096] In step S114, the dual-purpose pre-alignment control unit 144 (corresponding to the "orientation correction unit" and "eccentricity correction unit" of the present invention) performs mark pre-alignment in substantially the same manner as steps S20 to S25 in Fig. 7. The difference from the first embodiment is that in the first embodiment, the amount of eccentricity is measured using the laser pre-alignment sensor 37 in step S21 in Fig. 7, but in the second embodiment, the amount of eccentricity is measured using the standard pre-alignment sensor 33 (corresponding to the "eccentricity measurement unit" and "optical sensor" of the present invention).

[0097] In the second embodiment, the amount of eccentricity is measured using the standard pre-alignment sensor 33. Therefore, unlike the first embodiment, which uses the laser pre-alignment sensor 37, the distribution of the laser light intensity cannot be detected linearly. Therefore, in the second embodiment, the pre-alignment process can be performed satisfactorily for wafers W such as those shown by reference numerals 4A to 4D in FIG. 4 . Note that, since the second embodiment does not include the laser pre-alignment sensor 37, the pre-alignment process cannot be performed satisfactorily for wafers W attached to a support substrate S in a state where the wafer W is eccentric from the center of the support substrate S, such as those shown by reference numeral 4E in FIG. 4 , or for transparent wafers W such as those shown by reference numeral 4F. Therefore, the pre-alignment device according to the second embodiment does not use a support substrate S or is premised on the wafer W being placed at the center of the support substrate S. However, the number of components required is smaller than in the first embodiment, which provides significant cost benefits.

[0098] In this way, similar to the first embodiment, the pre-alignment device of the second embodiment can not only perform good pre-alignment processing on wafers W having a notch N on their outer edge, but can also perform good pre-alignment processing on wafers W that do not have a notch N.

[0099] Furthermore, since the second sub-chuck 34 and the laser pre-alignment sensor 37 can be omitted, the pre-alignment apparatus according to the second embodiment can be realized at lower cost than the first embodiment.

[0100] [Variations] In the first and second embodiments, the determination unit 43 or 143 determines whether to perform notch pre-alignment or mark pre-alignment based on information (pre-alignment setting information) set in advance by the user. However, the determination unit 43 or 143 may determine whether to perform notch pre-alignment or mark pre-alignment based on whether the alignment mark M is detected on the surface of the wafer W by the alignment mark detection unit 36.

[0101] Furthermore, in the first and second embodiments, the case where the pre-alignment device is applied to an inspection device is described. However, the pre-alignment device according to the present invention can also be applied to a wafer processing device for manufacturing, processing, inspecting, measuring, observing, etc., wafers W.

[0102] [effect] As described above, according to the pre-alignment apparatuses of the first and second embodiments, the alignment mark M formed on the surface of the wafer W is detected by the alignment mark detection unit 36, and the orientation of the wafer W is corrected based on the alignment mark M detected by the alignment mark detection unit 36. This makes it possible to perform a good pre-alignment process even for a wafer W that does not have a notch N or a wafer W that has a notch N that is difficult to detect.

[0103] According to the pre-alignment device of the first embodiment, 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 amount of eccentricity of the wafer W is measured by the laser pre-alignment sensor 37. This makes it possible to perform a good pre-alignment process even for a wafer W to which the support substrate S is attached eccentrically.

[0104] According to the pre-alignment apparatus of the second embodiment, if a notch N is formed in the wafer W and the notch N can be detected by the standard pre-alignment sensor 33, the standard pre-alignment sensor 33 measures the eccentricity of the wafer W and corrects the orientation of the wafer based on the notch N. 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 eccentricity of the wafer W and the alignment mark detection unit 36 ​​corrects the orientation of the wafer based on the alignment mark M. This makes it possible to realize a pre-alignment apparatus at lower cost than in the first embodiment.

[0105] 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 spirit of the present invention. [Explanation of symbols]

[0106] 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 unit, 36...alignment mark detection unit, 37...laser pre-alignment sensor, 40,140...control unit, 41...main body control unit, 42...arm control unit, 43,143...determination unit, 44...standard pre-alignment control unit, 45...mark pre-alignment control unit, 361...field of view range, 362...search range, 371...laser emission surface, 372...laser receiving surface, C...chipping, N...notch, M...alignment mark, W...wafer

Claims

1. A pre-alignment apparatus for pre-aligning a wafer, comprising: the wafer has an alignment mark indicating the orientation of the wafer; a first sub-chuck and a second sub-chuck that can hold and rotate the wafer; a notch detector that detects the position of a notch that indicates the orientation of the wafer held by the first sub-chuck; an alignment mark detector that detects the position of the alignment mark on the wafer held by the second sub-chuck; an orientation correction unit that corrects an orientation of the wafer by changing a rotational position of the first sub-chuck or the second sub-chuck based on 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; Equipped with the alignment mark is a mark provided on the main surface of the wafer other than the outer edge portion and detectable by the alignment mark detection unit; Pre-alignment device.

2. an eccentricity measuring unit for measuring an eccentricity of a center of the wafer with respect to a rotation center of the first sub-chuck, the first eccentricity measuring unit having a non-laser light projecting unit and a non-laser light receiving unit for receiving the non-laser light irradiated from the non-laser light projecting unit, and configured by a total light amount detection type optical sensor for outputting a total light amount obtained by the non-laser light receiving unit; an eccentricity measuring unit that measures an eccentricity of the center of the wafer with respect to a rotation center of the second sub-chuck, the second eccentricity measuring unit having a laser beam projector and a laser beam receiver that receives a laser beam irradiated from the laser beam projector, and configured by a laser sensor that can detect the wafer held by the second sub-chuck; an eccentricity correction unit that corrects eccentricity of the wafer by changing a 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; The pre-alignment apparatus of claim 1 , comprising:

3. A pre-alignment method for pre-aligning a wafer, comprising: the wafer has an alignment mark indicating the orientation of the wafer; a detection step selectively performing a notch detection step of detecting the position of a notch indicating the orientation of the wafer held by a rotatable first sub-chuck that holds the wafer, and an alignment mark detection step of detecting the position of the alignment mark of the wafer held by a rotatable second sub-chuck that holds the wafer; an orientation correcting step of correcting an orientation of the wafer by changing a 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 detecting step; Equipped with the alignment mark is a mark provided on a main surface of the wafer other than an outer edge portion thereof and detectable by the alignment mark detection step; Pre-alignment method.

4. an eccentricity measuring step selectively performing a first eccentricity measuring step of measuring an eccentricity of the center of the wafer relative to the rotation center of the first sub-chuck, the first eccentricity measuring step being performed using a total light amount detection type optical sensor having a non-laser light projector and a non-laser light receiving unit that receives non-laser light irradiated from the non-laser light projector and that outputs a total light amount obtained by the non-laser light receiving unit; and a second eccentricity measuring step of measuring an eccentricity of the center of the wafer relative to the rotation center of the second sub-chuck, the second eccentricity measuring step being performed using a laser type sensor having a laser light projector and a laser light receiving unit that receives laser light irradiated from the laser light projector and that can detect the wafer. an eccentricity correcting step of correcting the eccentricity of the wafer by changing a 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 measuring step; The pre-alignment method of claim 3 , comprising:

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