JP2014074683A - Parallelism measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method that can obtain a sharp image of reflection light in measurement of parallelism of two planes facing each other.SOLUTION: The parallelism measuring method includes the steps of: arranging a semi-transmissive member of a reflection member such that a surface of the semi-transmissive member thereof forms an angle of almost 45 degrees with respect to a second measured plane; measuring an angle of a first reflection beam 25 in which an incident light beam 24 is reflected at an interface 10 of the semi-transmissive member of the reflection member, next reflected at the second measured plane, once again reflected at the interface of the semi-transmissive material and returned in an incident direction; measuring an angle of a second reflection beam 26 in which the incident light beam 24 is reflected at the interface 10 of the semi-transmissive member of the reflection member, next reflected at the second measured plane, next passes through the semi-transmissive member of the reflection member, next reflected at a first measured plane, once again passes through the semi-transmissive member of the reflection member, once again reflected at the second measured plane once again, reflected at the interface 10 of the semi-transmissive member and returned in the incident direction; and calculating an angle difference between the first measured plane and the second measured plane from the angles of the first and second reflection beams.

Description

  The present invention relates to a method for measuring the parallelism of two opposing surfaces.

  In certain manufacturing processes, it is necessary to keep the two surfaces parallel within a very precise tolerance, ie within a few seconds. For example, in the process of bonding a semiconductor chip to a substrate, the parallelism of the semiconductor chip to the substrate is to ensure that each mounting pad on the semiconductor chip is aligned and bonded to the corresponding bonding pad on the substrate. This is an important issue. If there is even a slight non-parallel property between the semiconductor chip and the substrate, there may be a problem in the reliability of electrical connection at the joint.

  When bonding the semiconductor chip to the substrate, the robot arm is operated so that a vacuum suction jig having a flat suction surface sucks the semiconductor chip and places it on the substrate placed on the mounting base. . Usually, the orientation of the vacuum suction jig is adjusted so that the parallelism between the semiconductor chip and the substrate (that is, the parallelism between the vacuum suction jig and the mounting base) is within a predetermined tolerance. Here, a laser interferometer or the like is used to measure the parallelism. However, the laser interferometer is expensive and has a problem of complicated operation.

  Therefore, for example, Patent Document 1 discloses a method that enables simple and inexpensive measurement of the parallelism of two surfaces with a precision of the order of seconds with a simple configuration using a beam splitter and a mirror. Is disclosed.

Japanese Patent Application Laid-Open No. 2011-149776 JP 2000-074617 A

  The following analysis is given from the perspective of the present invention.

  However, in the measurement method according to Patent Document 1, the incident light beam from the autocollimator has four different paths (the path a, the path b, the path c, and the path d; The parallelism of the two surfaces is measured by four reflected light beams that pass back to the autocollimator. When four reflected light beams are used in this way, there is a problem that the reflected light beams are susceptible to interference. For example, the reflected light of the path d is susceptible to interference between the reflected light of the path b and the reflected light of the path c, and as a result, the autocollimator image by the reflected light of the path d is unclear and difficult to measure.

  Therefore, an object of the present invention is to provide a parallelism measuring method that can obtain a clear reflected light image.

  The parallelism measuring method according to the first aspect of the present invention is a method for measuring the parallelism between a first measured surface having light reflectivity and a second measured surface having light reflectivity using a reflecting member. It is. Here, the reflecting member includes a semi-transmissive member, and has a property of reflecting a part of incident light and transmitting a part thereof. The parallelism measuring method includes the following steps. That is, the parallelism measuring method includes a step of arranging the surface of the translucent member of the reflecting member so as to have an angle of approximately 45 degrees with respect to the second measured surface. Further, the parallelism measuring method is such that the incident light beam is reflected at the interface of the semi-transmissive member of the reflecting member, then reflected by the second measured surface, and again reflected by the interface of the semi-transmissive member of the reflecting member. Measuring the angle of the first reflected beam returning to the incident direction. Further, in the parallelism measuring method, the incident light beam is reflected at the interface of the semi-transmissive member of the reflecting member, then reflected by the second measured surface, and then transmitted through the semi-transmissive member of the reflecting member, Next, the light is reflected by the first surface to be measured, is again transmitted through the semi-transmissive member of the reflecting member, is reflected again by the second surface to be measured, and is reflected by the interface of the semi-transmissive member of the reflecting member. Measuring the angle of the second reflected beam returning in the direction. Further, the parallelism measuring method includes a step of calculating an angle difference between the first measured surface and the second measured surface from the measured angles of the emitted light of the first and second paths.

  In the parallelism measuring method according to the second aspect of the present invention, the parallelism between the first measured surface having light reflectivity and the second measured surface having light reflectivity is obtained using a reflecting member and a wedge substrate. It is a method of measuring. Here, the reflecting member includes a semi-transmissive member, and has a property of reflecting a part of incident light and transmitting a part thereof. The parallelism measuring method includes the following steps. That is, the parallelism measuring method includes a step of arranging the surface of the translucent member of the reflecting member so as to have an angle of approximately 45 degrees with respect to the second measured surface. The parallelism measuring method includes a step of inserting the wedge substrate between the reflecting member and the first measured surface. Further, the parallelism measuring method is such that the incident light beam is reflected at the interface of the semi-transmissive member of the reflecting member, then reflected by the second measured surface, and again reflected by the interface of the semi-transmissive member of the reflecting member. Measuring the angle of the first reflected beam returning to the incident direction. Further, in the parallelism measuring method, the incident light beam is reflected at the interface of the semi-transmissive member of the reflecting member, then reflected by the second measured surface, and then transmitted through the semi-transmissive member of the reflecting member, Next, the light passes through the wedge substrate, then reflects on the first measured surface, again passes through the wedge substrate, again passes through the semi-transmissive member of the reflecting member, and again reflects on the second measured surface, And measuring an angle of the second reflected beam that is reflected at the interface of the semi-transmissive member of the reflective member and returns to the incident direction. Further, in the parallelism measuring method, the angle of the second reflected beam is changed by rotating the wedge substrate around the normal line of the wedge substrate as a rotation axis, and the locus center of the changed angle of the second reflected beam is determined. Calculating. Further, the parallelism measuring method includes a step of calculating an angle difference between the first measured surface and the second measured surface from the locus center of the angle of the first reflected beam and the angle of the second reflected beam. .

  In the parallelism measuring method according to the third aspect of the present invention, the parallelism between the first measured surface that is light-reflective and the second measured surface that is light-reflective is obtained using a reflecting member and a wedge substrate. It is a method of measuring. Here, the reflecting member includes a semi-transmissive member, and has a property of reflecting a part of incident light and transmitting a part thereof. The parallelism measuring method includes the following steps. That is, the parallelism measuring method includes a step of arranging the surface of the translucent member of the reflecting member so as to have an angle of approximately 45 degrees with respect to the second measured surface. The parallelism measuring method includes a step of inserting the wedge substrate between the reflecting member and the second measured surface. Further, the parallelism measuring method is such that the incident light beam is reflected at the interface of the semi-transmissive member of the reflecting member, then transmitted through the wedge substrate, and then reflected by the second surface to be measured. Measuring the angle of the first reflected beam that is transmitted, reflected again at the interface of the semi-transmissive member of the reflective member and returned to the incident direction. Further, the parallelism measuring method is such that the incident light beam is reflected at the interface of the semi-transmissive member of the reflecting member, then transmitted through the wedge substrate, then reflected by the second measured surface, and again the wedge substrate. Is then transmitted through the semi-transmissive member of the reflective member, then reflected by the first surface to be measured, again through the semi-transmissive member of the reflective member, again through the wedge substrate, and again through the first substrate. Measuring the angle of the second reflected beam reflected at the surface to be measured, again transmitted through the wedge substrate, and reflected at the interface of the semi-transmissive member of the reflective member and returning to the incident direction. Further, in the parallelism measuring method, the angle of the first reflected beam and the angle of the second reflected beam are changed by rotating the wedge substrate with the normal line of the wedge substrate as a rotation axis, and the changed first angle is changed. Calculating a trajectory center of each of the angle of the reflected beam and the angle of the second reflected beam. Furthermore, the parallelism measuring method calculates an angle difference between the first measured surface and the second measured surface from the locus centers of the angles of the first reflected beam and the second reflected beam. including.

  According to the parallelism measuring method of the present invention, it is possible to provide a parallelism measuring method capable of obtaining a clear reflected light image.

It is a figure for demonstrating the parallelism measuring method which concerns on 1st Embodiment. It is a figure for demonstrating the principle of the parallelism measuring method which concerns on 1st Embodiment. It is a figure for demonstrating the angle of the reflected beam which passed the path | route A in FIG. It is a figure for demonstrating the angle of the reflected beam which passed the path | route B in FIG. It is a flowchart which shows the parallelism measuring method which concerns on 1st Embodiment. It is a figure for demonstrating the 1st parallelism measuring method in 1st Embodiment. It is an example of the measurement result in FIG. It is a figure which shows the state which performed the parallelism adjustment based on the 1st parallelism measuring method in 1st Embodiment. It is an example of the measurement result in FIG. It is a figure for demonstrating the 2nd parallelism measuring method in 1st Embodiment. It is a figure for demonstrating the 2nd parallelism measuring method in 1st Embodiment. It is an example of the measurement result in FIG. It is a figure which shows the state which performed the parallelism adjustment based on the 2nd parallelism measuring method in 1st Embodiment. It is an example of the measurement result in FIG. It is a figure for demonstrating the principle of the wedge board | substrate in FIG. It is a flowchart which shows the parallelism measuring method which concerns on the modification of 1st Embodiment. It is a figure for demonstrating the parallelism measuring method which concerns on 2nd Embodiment. It is a figure which shows the state which performed the parallelism adjustment based on the 1st parallelism measuring method in 4th Embodiment. It is a figure for demonstrating the 2nd parallelism measuring method in 4th Embodiment. It is a figure for demonstrating the 2nd parallelism measuring method in 4th Embodiment. It is a figure for demonstrating the parallelism measuring method which concerns on 5th Embodiment. It is a figure for demonstrating the principle of an autocollimator. It is a figure for demonstrating the principle of an autocollimator. It is a figure for demonstrating the influence of the angle error of the 45 degree surface of a beam spiriter.

  First, an outline of an embodiment of the present invention will be described. Note that the reference numerals of the drawings added in the description of the outline of the embodiment are merely examples for helping understanding, and are not intended to be limited to the illustrated modes.

  In one embodiment of the present invention, the parallelism measuring method includes a first surface to be measured 5 that is light-reflective as shown in FIGS. 1 and 5 (in FIG. 1, the reflecting surface of the upper mirror 5 is used). , And the second measured surface 6 that is light-reflective (the reflective surface of the lower mirror 6 is used in FIG. 1) is measured using a reflective member 71. Here, the reflecting member 71 includes the semi-transmissive member 10 and has a property of reflecting a part of incident light and transmitting a part thereof. The parallelism measuring method includes the following steps. That is, the parallelism measuring method includes a step (S10) in which the surface of the semi-transmissive member 10 of the reflecting member 71 is arranged at an angle of approximately 45 degrees with respect to the second measured surface 4. Further, the parallelism measurement method is such that the incident light beam 24 is reflected at the interface of the semi-transmissive member 10 of the reflecting member 71, then reflected by the second measured surface 6, and again the interface of the semi-transmissive member 10 of the reflecting member 71. (S11) which measures the angle 251 of the 1st reflected beam which reflects and returns to an incident direction. Further, in the parallelism measuring method, the incident light beam 24 is reflected at the interface of the semi-transmissive member 10 of the reflecting member 71, then reflected by the second measured surface 6, and then transmitted through the semi-transmissive member 10 of the reflecting member 71. Then, the light is reflected by the first measured surface 5, is again transmitted through the semi-transmissive member 10 of the reflective member 71, is reflected again by the second measured surface 6, and is reflected by the interface of the semi-transmissive member 10 of the reflective member 71. And measuring the angle 261 of the second reflected beam returning to the incident direction (S12). Further, the parallelism measuring method calculates an angular difference between the first measured surface 5 and the second measured surface 6 from the measured angles (251, 261) of the first and second reflected beams (S13). including.

  As shown in either FIG. 5 or FIG. 8, the parallelism measuring method is based on the calculated angle difference between the first measured surface 5 and the second measured surface 6 and the angle of the first reflected beam 25. A step (S14) of matching the parallelism between the first measured surface 5 and the second measured surface 6 so that the angles of the second reflected beams 26 coincide with each other may be further included.

  The parallelism measuring method is a method for measuring the parallelism between the first measured surface 5 and the second measured surface 6 as shown in any of FIGS. 5 and 10 to 12, and includes the following steps. Further, it may be included. That is, the step (S15) of inserting the wedge substrate 8 between the reflecting member 71 and the first measured surface 5 and the angle of the second reflected beam by rotating the wedge substrate 8 with the normal 30 of the wedge substrate as the rotation axis. 261 is changed to calculate the locus center 31 of the changed angle of the second reflected beam (S16), and the first measured object is calculated from the angle 251 of the first reflected beam and the locus center 31 of the angle of the second reflected beam. A step of calculating an angle difference between the surface 5 and the second measured surface 6 (S17) may be further included.

  The parallelism measuring method is a method of measuring the parallelism between the first measured surface 5 and the second measured surface 6 as shown in any of FIGS. And inserting the wedge substrate 8 between the reflecting member 71 and the second measured surface 6 instead of inserting the wedge substrate 8 between the first measured surface 5 and the first measured surface 5. The angle 251 of the first reflected beam and the angle 261 of the second reflected beam are changed by rotating about 30 as the rotation axis, and the locus centers of the changed angle 251 of the first reflected beam and angle 261 of the second reflected beam are changed. A step of calculating, and a step of calculating an angular difference between the first measured surface 5 and the second measured surface 6 from the respective locus centers of the angle 251 of the first reflected beam and the angle 261 of the second reflected beam. Even if you include There.

  As shown in any of FIGS. 5, 13 to 14, and 20, the parallelism measuring method is performed so that the locus center 31 of the angle of the second reflected beam coincides with the angle 251 of the first reflected beam. A step of matching the parallelism between the first measured surface 5 and the second measured surface 6 (S19 in FIG. 5 and the like) may be further included.

  As shown in any of FIGS. 5, 13 to 14, and 20, the parallelism measurement method has a predetermined angle difference between the locus center 31 of the second reflected beam angle and the angle 251 of the first reflected beam. It further includes a determination step (S18) for determining whether or not it is within a threshold, and when it is determined that the angular difference is not within a predetermined threshold, the first measured surface 5 and the second measured surface 6 The step of aligning the parallelism (S19), the wedge substrate 8 is rotated about the normal 30 of the wedge substrate as the rotation axis, the angle of the second reflected beam is changed, and the locus center 31 of the changed angle of the second reflected beam is obtained. The step of calculating (S20), the step of calculating the angle difference between the angle 251 of the first reflected beam and the locus center 31 of the angle of the second reflected beam (S21), and the determination step (S18) are repeated. even if There.

  The reflecting member may be a cube type beam splitter (71 in FIG. 1) or a plate type beam splitter (72 in FIG. 21).

  In the parallelism measuring method, the angle (251, 261) of the first and second reflected beams may be measured using the autocollimator 20.

  The parallelism measuring method according to another embodiment of the present invention includes a first measured surface 5 that is light reflective and a second measured surface that is light reflective as shown in either FIG. 1 or FIG. In this method, the parallelism with the surface 6 is measured using the reflecting member 71 and the wedge substrate 8. Here, the reflecting member 71 includes the semi-transmissive member 10 and has a property of reflecting a part of incident light and transmitting a part thereof. The parallelism measuring method includes the following steps. That is, the parallelism measuring method includes a step (S10) in which the surface of the semi-transmissive member 10 of the reflecting member 71 is arranged at an angle of about 45 degrees with respect to the second measured surface 6. Further, the parallelism measuring method includes a step (S15) of inserting the wedge substrate 8 between the reflecting member 71 and the first measured surface 5. Further, in the parallelism measuring method, the incident light beam 24 is reflected at the interface of the semi-transmissive member 10 of the reflecting member 71, then reflected by the second measured surface 6, and again reflected by the semi-transmissive member 10 of the reflecting member 71. Measuring the angle of the first reflected beam 25 to return to the incident direction. Further, in the parallelism measuring method, the incident light beam 24 is reflected at the interface of the semi-transmissive member 10 of the reflecting member 71, then reflected by the second measured surface 6, and then transmitted through the semi-transmissive member 10 of the reflecting member 71. Then, the light passes through the wedge substrate 8, is then reflected by the first measured surface 5, is again transmitted through the wedge substrate 8, is again transmitted through the semi-transmissive member 10 of the reflective member 71, and is again reflected by the second measured surface 6. Measuring the angle of the second reflected beam 26 that reflects and reflects off the interface of the transflective member 10 of the reflecting member 71 back to the incident direction. Further, the parallelism measurement method is such that the wedge substrate 8 is rotated about the normal line 30 of the wedge substrate as the rotation axis to change the angle 261 of the second reflected beam, and the locus center 31 of the changed angle of the second reflected beam is obtained. A calculating step (S16). Further, the parallelism measuring method calculates an angle difference between the first measured surface 5 and the second measured surface 6 from the locus center 31 of the angle 251 of the first reflected beam and the angle of the second reflected beam ( S17).

  As shown in any of FIGS. 19 to 20, the parallelism measuring method according to yet another embodiment of the present invention includes a first measured surface 5 that is light reflective and a second measured surface that is light reflective. In this method, the parallelism with the surface 6 is measured using the reflecting member 71 and the wedge substrate 8. Here, the reflecting member 71 includes the semi-transmissive member 10 and has a property of reflecting a part of incident light and transmitting a part thereof. The parallelism measuring method includes the following steps. That is, the parallelism measuring method includes a step of arranging the surface of the semi-transmissive member 10 of the reflecting member 71 so as to have an angle of about 45 degrees with respect to the second measured surface 6. The parallelism measuring method includes a step of inserting the wedge substrate 8 between the reflecting member 71 and the second measured surface 6. Further, in the parallelism measuring method, the incident light beam 24 is reflected at the interface of the semi-transmissive member 10 of the reflecting member 71, then transmitted through the wedge substrate 8, and then reflected by the second measured surface 6, and again the wedge substrate. 8 and measuring the angle 251 of the first reflected beam that is reflected again at the interface of the semi-transmissive member 10 of the reflective member 71 and returns to the incident direction. Further, in the parallelism measuring method, the incident light beam 24 is reflected at the interface of the semi-transmissive member 10 of the reflecting member 71, then transmitted through the wedge substrate 8, and then reflected by the second measured surface 6, and again the wedge substrate. 8, then transmitted through the semi-transmissive member 10 of the reflective member 71, then reflected by the first measured surface 5, again transmitted through the semi-transmissive member 10 of the reflective member 71, and again transmitted through the wedge substrate 8, A step of measuring an angle 261 of the second reflected beam that is reflected by the second measured surface 6 again, passes through the wedge substrate 8 again, and is reflected at the interface of the semi-transmissive member 10 of the reflective member 71 and returns to the incident direction. including. In addition, the parallelism measuring method rotates the wedge substrate 8 about the normal line 30 of the wedge substrate as a rotation axis to change the angle 251 of the first reflected beam and the angle 261 of the second reflected beam, thereby changing the changed first reflection. Calculating a trajectory center of each of the beam angle 251 and the second reflected beam angle 261. Further, in the parallelism measuring method, the angle difference between the first measured surface 5 and the second measured surface 6 is calculated from the trajectory centers of the angle 251 of the first reflected beam and the angle 261 of the second reflected beam. Including the steps of:

  Next, before explaining each embodiment of the present invention, in order to understand the measurement method of the present invention well, first, the operation principle of the autocollimator will be described.

  FIG. 22 is a diagram illustrating the operating principle of the autocollimator. The light beam 66 emitted from the optical semiconductor laser 60 becomes collimated light 67 by the first collimator lens 61, is bent by 90 degrees on the reflection surface of the beam splitter 62, enters the object, and is reflected by the measurement surface 63. The reflected collimated light 68 reflected again passes through the beam splitter 62, becomes the condensed light 69 by the second collimator lens 64, and detects the position of the condensed light by the CCD 65.

  For example, as shown in FIG. 22, when the measured surface 63 is inclined by an angle θ, the angle of the reflected collimated light 68 reflected by the inclined measured surface 63 varies. When the reflected collimated light 68 oscillated at the angle becomes the condensed light 69 by the second collimator lens 64, the collimated light oscillated at a certain angle from the axis of the second collimator lens 64 is incident on the second collimator lens 64. The imaging position of the light beam 69 is a distance L from the center of the CCD 65. At this time, the autocollimator detects the position L of the CCD 65, determines that the angle of the measured surface 63 has changed, and displays the changed angle. Here, the ratio of the distance between the angles θ and L of the measurement surface 63 is determined by the characteristics of the second collimator lens 64 and is constant.

  Further, as shown in FIG. 23, when the incident light beam 24 from the autocollimator is incident on the surface to be measured 63 tilted θ counterclockwise and reflected, the return light 42 is rotated 2θ counterclockwise from the incident light beam 24. Tilt. At that time, in order to display the angle of the surface to be measured 63, the autocollimator performs calculation inside the autocollimator and displays the angle of the surface to be measured 63 at half the detected angle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram for explaining a parallelism measuring method according to the first embodiment. In FIG. 1, the bottom surface (first measured surface 3) of the suction head 101 held at the lower part of the first device 1, and the upper surface (second measured surface) of the panel 201 arranged at the upper part of the second device 2. It is assumed that the parallelism of the two surfaces of 4) is measured using the autocollimator 20. Here, as shown in FIG. 1, in order to measure the parallelism between the bottom surface of the suction head 101 and the top surface of the board 201, the upper mirror 5 having a uniform thickness is attracted to the suction head 101 with the reflection surface down. The lower mirror 6 having a uniform thickness is disposed on the upper surface of the board 201 with the reflecting surface on the upper side.

  With the above configuration, the bottom surface (first measured surface 3) of the suction head 101 matches the upper side surface of the upper mirror 5, and the upper surface (second measured surface 4) of the panel 201 matches the lower side surface of the lower mirror 6. To do. Since the upper mirror 5 and the lower mirror 6 are uniform in thickness, the parallelism between the bottom surface of the suction head 101 and the top surface of the board 201 is the parallelism between the reflection surface of the upper mirror 5 and the reflection surface of the lower mirror 6. Match. Accordingly, the parallelism between the bottom surface (first measured surface 3) of the suction head 101 and the upper surface (second measured surface 4) of the board 201 is obtained by measuring the parallelism of the upper mirror 5 and the lower mirror 6. Can do.

  At this time, as shown in FIG. 1, the first measured surface 3 and the upper mirror 5 are counterclockwise θu with respect to the incident light beam 24 from the autocollimator 20, and the second measured surface 4 and the lower mirror 6 are It is assumed that the incident light beam 24 from the collimator 20 is inclined counterclockwise by θl.

  In addition, although the upper mirror 5 and the lower mirror 6 are used in 1st Embodiment, it is not limited to it, What is necessary is just to make two opposing surfaces light-reflective by some methods, respectively. For example, the lower surface of the suction head 101 and the upper surface of the board 201 may be made reflective.

  As shown in FIG. 1, a beam splitter 71 is disposed between the upper mirror 5 and the lower mirror 6. The wedge substrate 8 inserted between the beam splitter 71 and the upper mirror 5 is inserted in the middle of the measurement process. The left part of FIG. 1 shows a cross-sectional view of the upper mirror 5, the wedge substrate 8, the beam splitter 71, the lower mirror 6, and the like.

  The beam splitter 71 is used as the semi-transmissive member 10 having a semi-transmissive surface. In the beam splitter 71 having four surfaces configured to be light-transmitting, a 45-degree surface (corresponding to a semi-transmissive member) 10 is formed on the diagonal surface from the lower surface corner of the beam splitter 71 to the upper surface corner (45 + θb). Inclined at a degree. Here, θb includes an angle error of the surface 10 of 45 degrees and an error when the beam splitter 71 is disposed. That is, the angle of the surface 10 of 45 degrees with respect to the incident light beam 24 from the autocollimator 20 is (45 + θb) degrees.

  Further, in order to suppress reflection of the light incident surface (11, 12, etc. in FIG. 1) on the beam splitter 71, an antireflection coating is applied to the light incident surface.

  The beam splitter 71 used in the first embodiment is a cube-type beam splitter. The cube-type beam splitter is composed of two right-angle prisms, and an optical thin film (equivalent to the semi-transmissive member 10) is vapor-deposited on the slope of one of the right-angle prisms. It is composed. The cube beam splitter has the following merits not found in the plate beam splitter (72 in FIG. 21) described later. That is, there is no refraction of transmitted light, the optical thin film is in a glass substrate and does not touch the air, the film itself is less deteriorated, and the incident angle condition is normal incidence, so alignment is easy. , Etc.

  Moreover, the parallelism measuring method of 1st Embodiment uses the autocollimator 20, the arithmetic unit 22, the display apparatus 21, and the memory | storage device 23, as shown in FIG. The autocollimator 20 functions based on the above-described principle (FIGS. 22 to 23). As shown in FIG. 1, the autocollimator 20 irradiates the beam splitter 71 with the incident light beam 24 and returns the first light that is return light. The reflected beam 25 and the second reflected beam 26 are received. Further, the arithmetic unit 22 calculates the angles (251, 261) of the respective reflected beams based on the detection results of the first reflected beam 25 and the second reflected beam 26 by the CCD, and as shown in FIG. 21. Further, the arithmetic unit 22 has a function of calculating an angle difference between the upper mirror 5 and the lower mirror 6, a function of calculating an adjustment amount for adjusting the parallelism of the two surfaces within a desired accuracy, and the like. The storage device 23 is for storing various parameters necessary for the calculation of the calculation device 22, results calculated by the calculation device 22, and the like.

  Next, the coordinate system of the 1st apparatus 1, the 2nd apparatus 2, and the autocollimator 20 is demonstrated. First, the coordinates in the first device and the second device 2 are defined in an XYZ orthogonal coordinate system as shown in FIG. The Z axis is defined to coincide with the direction of gravity. That is, the XY plane is defined to coincide with the horizontal plane. For example, when the first device 1 and the second device 2 are devices for bonding a semiconductor chip to a substrate, the X axis and the Y axis on the XY plane correspond to the substrate when the substrate is placed on the board 201. Are set so that the directions of two orthogonal sides are the X axis and the Y axis, respectively. Further, for example, it is assumed that the first device 1 has a mechanism that makes it possible to adjust the inclinations in the X direction and the Y direction with respect to the first measured surface 3.

  As shown in FIG. 1, when the beam splitter 71 and the autocollimator 20 are installed, the coordinate system (θx, θy) of the autocollimator 20 and the XYZ coordinate system of the first device 1 and the second device 2 are It shall be calibrated. Specifically, as shown in FIG. 1, when there is an inclination of (θx, θy, θz) in the XYZ coordinate system, the autocollimator 20 detects the θx component and the θy component and displays them on the display device 21 ( θx, θy) are displayed.

  Next, the principle of the method for measuring parallelism according to the first embodiment will be described in detail with reference to FIGS. In FIG. 2, the incident light beam 24 from the autocollimator 20 is transmitted or reflected by the beam splitter 71, the upper mirror 5, and the lower mirror 6 and passes through two different paths (path A and path B), and again auto Return to the collimator 20. Here, light that returns to the autocollimator 20 through the path A is referred to as a first reflected beam 25, and light that returns to the autocollimator 20 through the path B is referred to as a second reflected beam 26. Next, each route A and route B will be described in detail.

(Route A)
FIG. 3 shows the light of the path A. This light is reflected at the interface of the 45-degree surface 10 of the beam splitter 71, reflected by the lower mirror 6, reflected again at the interface of the 45-degree surface 10, and becomes the first reflected beam 25 to become the autocollimator 20. Return to. Here, if the inclination angle of the 45-degree surface 10 of the beam splitter 71 is (45 + θb) degrees and the inclination angle of the lower mirror 6 is θl, the angle difference of the first reflected beam 25 with respect to the incident light beam 24 is expressed by the equation (1). ).

4θb-2θl Formula (1)

Here, since the angle measured by the autocollimator 20 displays half of the actual angle as described above, the angle difference between the first reflected beam 25 measured by the autocollimator 20 and the incident light beam 24 is Equation (2) is obtained.

2θb−θl Formula (2)

The process of deriving equation (1) will be described below. First, the path A of the first reflected beam 25 is divided into the following two.
A-1. The light is reflected at the interface of the 45-degree surface 10 of the beam splitter 71 and is reflected again by the 45-degree surface 10 of the beam splitter 71.
A-2. Reflected by the lower mirror 6.

For each of the above two paths, the angle difference between the incident light on each path (A-1, A-2) and the light that has passed through each path is obtained. The angle difference in each path is as follows.
A-1. FIG. 24 is a diagram showing the angle of the reflected light with respect to the incident light when there is an angle error θb on the 45-degree reflective surface 10. Here, it is assumed that the lower mirror 6 is placed parallel to the incident light. As shown in FIG. 24, the angle of the reflected light with respect to the incident light is 4θb.
A-2. Assuming that the lower mirror 6 is tilted by θ1 counterclockwise, as described in FIG. 23, the angle of the reflected light with respect to the incident light is 2θ1.
Therefore, when the paths A-1 and A-2 are combined, Expression (1) is derived.

(Route B)
FIG. 4 shows the light of the path B. This light is reflected at the interface of the 45-degree surface 10 of the beam splitter 71, reflected by the lower mirror 6, transmitted through the 45-degree surface 10, reflected by the upper mirror 5, and again passes through the 45-degree surface 10. Then, the light is reflected again by the lower mirror 6, is reflected again by the interface of the 45 ° surface 10, and returns to the autocollimator 20 as the second reflected beam 26. If the inclination angle of the 45-degree surface 10 of the beam splitter 71 is (45 + θb) degrees, the inclination angle of the upper mirror 5 is θu, and the inclination angle of the lower mirror 6 is θ1, the angle of the second reflected beam 26 with respect to the incident light beam 24. Is represented by Formula (3).

4θb-4θl + 2θu Formula (3)

Here, since the angle measured by the autocollimator 20 displays half of the actual angle as described above, the angle difference between the second reflected beam 26 measured by the autocollimator 20 and the incident light beam 24 is Equation (4) is obtained.

2θb-2θl + θu Formula (4)

The process of deriving equation (3) will be described below. First, the path B of the second reflected beam 26 is divided into the following three.
B-1. The light is reflected at the interface of the 45-degree surface 10 of the beam splitter 71 and is reflected again at the interface of the 45-degree surface 10 of the beam splitter 71.
B-2. Reflected by the lower mirror 6.
B-3. Reflected by the upper mirror 5.

For each of the three paths, the angle difference between the incident light on each path (B-1, B-2, B-3) and the light that has passed through each path is obtained. The angle difference in each path is as follows.
B-1. It becomes the same as A-1 of route A.
B-2. It is the same as A-2 of route A. However, since the lower mirror 6 is reflected twice, the reflected light has an angle difference of 4θl with respect to the incident light.
B-3. When the upper mirror 5 is inclined counterclockwise by θu, the reflected light has an angle difference of 2θu with respect to the incident light.
Therefore, when the paths of B-1, B-2, and B-3 are combined, Expression (3) is derived.

By subtracting equation (3) from equation (1), equation (5) is obtained, and the parallelism between the upper mirror 5 and the lower mirror 6 can be derived.

2θu-2θl Formula (5)

When the measurement is performed using the autocollimator 20, as described above, it is displayed with a value that is half of the actual angle. Therefore, the measurement value by the autocollimator 20 is expressed by the following equation (6).

θu−θl Formula (6)

  When the angle of the upper mirror 5 is adjusted to be parallel to the angle of the lower mirror 6, θu = θl, and therefore the value of equation (6) becomes zero. As described above, even if there is an angle error θb on the 45-degree surface 10 of the beam splitter 71, the angle difference between the first reflected beam 25 and the second reflected beam 26 does not depend on the angle error θb, and the upper mirror 5 and the lower mirror 6 It turns out that it becomes equal to the angle difference of. Therefore, in order to make the upper mirror 5 and the lower mirror 6 parallel to each other, the first reflected beam 25 and the second reflected beam 26 may be matched.

  Next, the parallelism measuring method according to the first embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing the parallelism measuring method according to the first embodiment. The states of the incident light beam 24, the first reflected beam 25, and the second reflected beam 26 in each step of the flowchart of FIG. 5 will be described with reference to any of FIGS.

  In FIG. 5, first, a beam splitter 71 is inserted between the upper mirror 5 and the lower mirror 6, and the surface of the semi-transmissive member 10 (45-degree surface) of the beam splitter 71 is moved to the lower mirror 6 (second measured surface). It is arranged so as to be 45 degrees with respect to 4) (S10). FIG. 6 shows a state where the beam splitter 71 is arranged in step S10. The 45 degree surface 10 is not required to be exactly 45 degrees with respect to the incident light beam 24 as described above, and may include an angle error θb as shown in FIG.

  Next, in FIG. 5, the angle of the first reflected beam 25 is measured (S11). Specifically, the first collimated beam 25 is received by the autocollimator 20, the detection data by the CCD is calculated by the calculation device 22, and then displayed on the display device 21. Referring to FIG. 6, the angle 251 of the first reflected beam is displayed on the display device 21.

  Next, in FIG. 5, the angle of the second reflected beam 26 is measured (S12). Specifically, the second collimated beam 26 is received by the autocollimator 20, the detection data by the CCD is calculated by the calculation device 22, and then displayed on the display device 21. Referring to FIG. 6, the angle 261 of the second reflected beam is displayed on the display device 21.

ここで、Δθｘ＝θｘ２−θｘ１ 式（８）
Δθｙ＝θｙ２−θｙ１ 式（９） Next, in FIG. 5, the difference between the angle 251 of the first reflected beam and the angle 261 of the second reflected beam displayed on the display device 21 is calculated by the calculation device 22 (S13). The angle difference θ between the angle 251 of the first reflected beam and the angle 261 of the second reflected beam, the x component θx of the angle difference, and the y component θy of the angle difference are calculated by the following equations (7) to (9).

Here, Δθx = θx2−θx1 Formula (8)
Δθy = θy2−θy1 Formula (9)

  FIG. 7 shows the angle 251 of the first reflected beam and the angle 261 of the second reflected beam by the display device 21 of FIG. FIG. 7 shows θ, Δθx, and Δθy calculated by equations (7) to (9).

  Expressions (7) to (9) correspond to the angular difference between the upper mirror 5 and the lower mirror 6 as described above. Steps S10 to S13 described above (steps within a broken line frame in FIG. 5) are referred to as “first parallelism measuring method”.

  Next, when the parallelism of the upper mirror 5 and the lower mirror 6 is adjusted, the angle difference between the upper mirror 5 and the lower mirror 6 by the first parallelism measurement method (θ in equations (7) to (9), Based on (Δθx, Δθy), the parallelism of the upper mirror 5 and the lower mirror 6 is adjusted so that the angles of the first reflected beam 25 and the second reflected beam 26 coincide (S14). FIG. 8 shows a state in which the parallelism adjustment based on the first parallelism measurement method is performed. In FIG. 8, the parallelism between the two surfaces is adjusted by adjusting the angle of the upper mirror 5 by (Δθx, Δθy). FIG. 9 shows a display of the angle 251 of the first reflected beam and the angle 261 of the second reflected beam in the display device 21 after the parallelism adjustment. After the adjustment, the two reflected beams are displayed so as to overlap each other.

  As a result of the adjustment described above, the angle 251 of the first reflected beam and the angle 261 of the second reflected beam are gathered at one point as shown in FIG. It is not possible to determine exactly whether or not they exactly match, and it is not possible to perform measurement and adjustment with higher accuracy.

  Therefore, in the first embodiment, the two reflected beams can be measured with higher accuracy by the processes after step S15 described later. By performing the steps after step S15, the adjustment accuracy in step S14 does not need to be strict, and the angle 251 of the first reflected beam and the angle 261 of the second reflected beam need only be close to some extent.

  In the following, steps S15 to S17 (within the dot-and-dash line frame in FIG. 5) of FIG. 5 that enable more accurate measurement of the two reflected beams will be described in detail. The measurement in steps S15 to S17 is referred to as “second parallelism measurement method”. In FIG. 5, the wedge substrate 8 is inserted between the beam splitter 71 and the first measured surface 3 (S15). FIG. 10 shows a state in which the wedge substrate 8 is inserted. As shown in FIG. 10, when the wedge substrate 8 is inserted, the angle 261 of the second reflected beam changes by δ. The phenomenon in which the angle 261 of the second reflected beam changes by δ is related to the fact that both surfaces of the wedge substrate 8 have a small angle α that is not parallel, but the principle will be described later. .

  Next, in FIG. 5, when the wedge substrate 8 is rotated, the locus of the angle 261 of the second reflected beam is an arc whose center of rotation is the position of the angle 261 of the second reflected beam before the wedge substrate 8 is inserted. Draw. The locus center 31 (a, b) of the angle of the second reflected beam is obtained from the locus of the arc by the angle 261 of the second reflected beam (S16). FIG. 11 shows a state where the wedge substrate 8 is rotated in step S16 of FIG. As shown in FIG. 11, the wedge substrate 8 rotates with the normal 30 of the wedge substrate as a rotation axis. At this time, the locus 32 of the angle of the second reflected beam is drawn.

  FIG. 12 shows the display of the display device 21 of FIG. As shown in FIG. 12, the locus 32 of the angle of the second reflected beam when the wedge substrate 8 is rotated draws one circle when rotated once. The center of the circle is the center of the angle 261 of the second reflected beam before the wedge substrate 8 is inserted. Before the wedge substrate 8 is inserted, the angle 251 of the first reflected beam and the angle 261 of the second reflected beam (corresponding to the center of the circle) are located close to each other, so that they overlap, and the first reflected beam is overlapped. It is impossible to determine whether or not the angle 251 of the second reflected beam and the angle 261 of the second reflected beam exactly match each other. However, by inserting the wedge substrate 8 in this way, the angle 261 of the second reflected beam is changed. Since the first reflected beam angle 251 and the second reflected beam angle 261 overlap each other to move to a position where an arc separated by the distance δ is drawn, it is possible to solve the problem that strict evaluation cannot be performed.

尚、δは、ウェッジ基板８の屈折率ｎ、ウェッジ基板８の角度αにより決まる値である（式（２４）を参照）。δの具体的な計算方法については、後述する。 The locus center (a, b) of the second reflected beam 2 can be obtained from the equation of the circle of the equation (10). However, at least three or more points are necessary as the angle 261 (θx, θy) of the second reflected light.

Note that δ is a value determined by the refractive index n of the wedge substrate 8 and the angle α of the wedge substrate 8 (see Expression (24)). A specific method for calculating δ will be described later.

Next, in FIG. 5, the angle difference between the locus center 31 of the angle of the second reflected beam and the angle 251 of the first reflected beam is calculated (S17). FIG. 12 shows the angle difference Δθx of the x component and the angle difference Δθy of the y component between the locus center 31 of the angle of the second reflected beam and the angle 251 of the first reflected beam. The above Δθx and Δθy are calculated by equations (11) to (12).

Δθx = a−θx1 Formula (11)
Δθy = b−θy1 Formula (12)

  As described above, the second parallelism measurement method according to steps S15 to S17 in FIG. 5 uses the wedge substrate 8 to realize measurement with higher accuracy than the first parallelism measurement method.

  Next, in the processes after step S18 in FIG. 5, the measurement and adjustment are repeated until the desired parallelism is obtained by performing the parallelism accuracy based on the second parallelism measurement method.

ここで、θｘｔｈ、θｙｔｈは、それぞれ角度誤差のｘ成分、ｙ成分の閾値である。また、θｔｈは、角度誤差の大きさの閾値である。ここで、θｘｔｈ、θｙｔｈ、θｔｈは、要求される平行度により適宜設定する。例えば、秒オーダの平行度を要求する場合は、０．００１〜０．００５度の範囲に設定するのが望ましい。 First, in step S18 of FIG. 5, it is determined whether or not Δθx and Δθy satisfy either of the following formulas (13) and (14).
(Δθx, Δθy) ≦ (θxth, θyth) Equation (13)

Here, θxth and θyth are the threshold values of the x component and y component of the angle error, respectively. Θth is a threshold value of the magnitude of the angle error. Here, θxth, θyth, and θth are appropriately set according to the required parallelism. For example, when requesting parallelism on the order of seconds, it is desirable to set a range of 0.001 to 0.005 degrees.

  The first determination in step S18 is to determine whether or not the result of step S14 (parallelism adjustment based on the first parallelism measurement method) is within a desired accuracy. A process is complete | finished when it determines with Yes in step S18.

  On the other hand, when it is determined No in step S18, the first measured surface 3 and the second measured surface 3 are adjusted by adjusting the inclination of the upper mirror 5 based on the angle difference (Δθx, Δθy) as shown in FIG. The parallelism of the measurement surface 4 is matched (S19).

  Next, in FIG. 5, the wedge substrate 8 is rotated with the normal 30 of the wedge substrate as the rotation axis, and the locus center 31 (a, b) of the angle of the second reflected beam is calculated (S20). Here, since step S20 is the same as step S16, the overlapping description is omitted.

  Next, an angle difference (Δθx, Δθy) between the locus center 31 of the second reflected beam and the angle 251 of the first reflected beam is calculated (step S21). Here, since step S21 is the same as step S17, the overlapping description is omitted. And it returns to step S18 and repeats. The second and subsequent determinations in step S18 are to determine whether or not the result of step S19 (parallelism adjustment based on the second parallelism measurement method) is within a desired accuracy.

  FIG. 14 shows a display on the display device 21 when it is determined Yes in step S18 of FIG. As shown in FIG. 14, the locus center 31 of the angle of the second reflected beam coincides with the angle 251 of the first reflected beam, and the parallelism of the upper mirror 5 and the lower mirror 6 is adjusted within a desired accuracy. It shows that.

(Calculation method of δ)
A method of calculating the radius δ of the arc locus of the angle 261 of the second reflected beam will be described with reference to FIG. In FIG. 15, the wedge substrate 8 is not parallel on both sides and has a small angle α. When the wedge substrate 8 is inclined by θa degrees with respect to the incident light, the transmitted light is inclined by θw degrees with respect to the incident light. Assuming that the refractive index of the wedge substrate 8 is n, the refraction angle of the incident light in the wedge substrate 8 is β, and the exit angle is γ, these relationships are expressed by equations (15) to (15) as described in Patent Document 2. It is represented by (17).

n · sin β = sin θa Equation (15)
sinγ = n · sin (α + β) Equation (16)
θw = γ− (α + θa) Equation (17)

Actually, when the wedge substrate 8 is used, since θa = 0, when θa≈0, Equation (17) approximates Equation (18) from Equation (15) and Equation (16). be able to.

θw≈ (n−1) · α formula (18)

Accordingly, the light that has passed through the wedge substrate 8 has an angle shift corresponding to the angle represented by Expression (18). Here, if the angle α of the wedge substrate is sufficiently small, θw is also sufficiently small. Therefore, the light that has passed through the wedge substrate 8 is reflected by a plane perpendicular to the horizontal plane and returned to the wedge substrate 8 again. Since the angle change is the same as that in the equation (18), the angle deviation of the equation (19) occurs in the light reciprocating the wedge substrate 8.

2 ・ (n−1) ・ α Formula (19)

  Here, the material of the wedge substrate 8 is generally a glass material such as BK7, and n≈1.5. Furthermore, the angle α of the wedge substrate 8 is preferably about 0.1 degrees in consideration of the measurement angle range of the autocollimator 20 to be used. If the angle α is set to a relatively large angle such as 0.5 degrees, the measurement angle range of the autocollimator 20 may be deviated.

When the wedge substrate 8 is inserted, the angular difference between the first reflected beam 25 and the second reflected beam 26 displayed on the display device 21 is expressed by Equation (5) and Equation (19) to Equation (20).

2 · θu−2 · θl + 2 · (n−1) · α Equation (20)

On the other hand, the angle difference Δθh between the first measured surface 3 and the second measured surface 4 is expressed by Equation (21).

Δθh = θu−θl Formula (21)

Therefore, from Expression (20) and Expression (21), Expression (20) becomes Expression (22).

2 · Δθh + 2 · (n−1) · α Formula (22)

In the measurement by the autocollimator 20, since it is displayed with a value half the actual angle, the angle difference between the first reflected beam 25 and the second reflected beam 26 by the autocollimator 20 is expressed by the equation (23) from the equation (22). Become.

Δθh + (n−1) · α Formula (23)

Here, the second term of Expression (23) corresponds to the angle δ of the radius of the arc locus of the second reflected beam 26 (Expression (24)).

δ = (n−1) · α Formula (24)

  The effects of the first embodiment will be described below. In the method of measuring the parallelism of two surfaces according to Patent Document 1, reflected light by four paths (a path, b path, c path, and d path; see FIGS. 6 to 9 of Patent Document 1, respectively) For example, there is a problem that the reflected light of the path d is easily blurred due to interference between the reflected light of the path b and the reflected light of the path c. On the other hand, in the first parallelism measurement method of the first embodiment, as described in steps S11 to S14 in FIG. 5, only the reflected light of the two paths (the first reflected beam 25 and the second reflected beam 26). Therefore, each reflected light can be made less susceptible to interference by other reflected lights. As a result, the two reflected lights become clear and the effect that the angle measurement becomes easy can be obtained.

  Further, in the second parallelism measuring method of the first embodiment, the angle of one reflected light can be changed by the wedge substrate 8, so that the two reflected lights overlap when the two surfaces become nearly parallel. Therefore, the effect that the parallelism of the two surfaces can be adjusted with higher accuracy than the first parallelism measuring method can be obtained.

  Also, in the second parallelism measurement method of the first embodiment, since the reflected light is two, the locus when the wedge substrate 8 is rotated can be displayed more clearly. An effect is obtained.

  Further, in the first embodiment, it is not necessary to make the 45 degree surface of the beam splitter 71 exactly 45 degrees with respect to the incident light beam 24, so that the beam splitter 71 can be installed more easily. An effect is obtained.

(Modification of the first embodiment)
Next, a modification of the first embodiment will be described in detail with reference to FIG. FIG. 16 is a flowchart showing a parallelism measuring method according to a modification of the first embodiment. The difference from the first embodiment is that in the modified example of the first embodiment, the wedge substrate 8 is inserted from the beginning without performing steps S12 to S14 in FIG. 5 (first embodiment). This is the point that the measurement by the second parallelism measurement method and the parallelism adjustment based on the measurement result are performed. However, in the second parallelism measuring method in FIG. 16, it is necessary to measure the angle 251 of the first reflected beam, and therefore includes step S11. Each step in FIG. 16 is the same as the corresponding step in FIG.

  The deviation in parallelism between the first measured surface 3 and the second measured surface 4 is very small, and it is not necessary to adjust the parallelism in step S14 in FIG. 5, and only high-precision parallelism measurement and adjustment are required. In such a case, the modification of the first embodiment is effective.

  As described above, according to the modification of the first embodiment, the same effect as that of the first embodiment can be obtained, and the parallelism measurement and adjustment can be shortened when the parallelism shift is very small. The effect that it can do is acquired.

(Second Embodiment)
Next, the second embodiment will be described in detail with reference to FIG. FIG. 17 is a diagram showing a parallelism measuring method according to the second embodiment. In the second embodiment, the beam splitter 71 is set upside down. When the wedge substrate 8 is inserted into the optical path, the wedge substrate 8 is inserted between the beam splitter 71 and the lower mirror 6. The other points are the same as in the first embodiment.

  As shown in FIG. 17, the route A and the route B in FIG. 7 are obtained by turning the route A and the route B in FIG. 2 upside down. Accordingly, the first reflected beam 25 and the second reflected beam 26 in FIG. 17 are also the first reflected beam 25 and the second reflected beam 26 in FIG. Thus, since the two reflected beams are only upside down with respect to the first embodiment, according to the second embodiment, the same measurement and adjustment as in the first embodiment can be performed. it can.

  However, in the second embodiment, the parallelism adjustment is preferably performed by the lower mirror 6. This is because the change in the angle of the reflected beam due to the adjustment can be made only to the second reflected beam 26. For this reason, the configuration of the second embodiment is effective when there is a parallelism adjustment mechanism on the lower mirror 6 side of the upper mirror 5 and the lower mirror 6.

(Third embodiment)
Next, a third embodiment will be described. In the first embodiment, the angle of the first measured surface 3 (that is, the angle of the upper mirror 5) is adjusted so that the angles of the first measured surface 3 and the second measured surface 4 are matched in parallel. . On the other hand, the third embodiment is different from the first embodiment in that in the configuration shown in FIG. 1, the second measured surface 4 (that is, the angle of the lower mirror 6) is adjusted to adjust the parallelism of the two surfaces. It is a difference. About another point, it is the same as that of 1st Embodiment, and the overlapping description is abbreviate | omitted.

  When the angle of the second measured surface 4 (the angle of the lower mirror 6) is adjusted in the configuration of FIG. 1, the angles of both the first reflected beam 25 and the second reflected beam 26 change as can be seen from FIG. Therefore, it is relatively difficult to align the parallelism. However, when the angle of the second measured surface 4 is adjusted to a direction parallel to the angle of the first measured surface, the angular difference between the first reflected beam 25 and the second reflected beam 26 gradually decreases, and finally The points of the first reflected beam 25 and the second reflected beam 26 can be overlapped with each other.

  Also in the configuration of the second embodiment shown in FIG. 17, the first measured surface 3 and the second measured surface 4 are adjusted by adjusting the angle of the first measured surface 3 (upper mirror 5). These angles may be adjusted in parallel. Since the angles of both the first reflected beam 25 and the second reflected beam 26 change, it is relatively difficult to align them in parallel, but the points of the first reflected beam 25 and the second reflected beam 26 are finally overlapped. Can do.

(Fourth embodiment)
Next, a fourth embodiment will be described in detail with reference to FIGS. The difference of the fourth embodiment from the first embodiment is that the wedge substrate 8 is inserted between the beam splitter 71 and the lower mirror 6 in the fourth embodiment.

  FIG. 18 shows that in the fourth embodiment, the angle of the first reflected beam 25 and the angle of the second reflected beam 26 are adjusted by adjusting the parallelism based on the first parallelism measurement method before inserting the wedge substrate 8. The state adjusted to be close to some extent is shown (corresponding to the state of FIG. 8 of the first embodiment).

  FIG. 19 shows a state in which the wedge substrate 8 is further inserted between the beam splitter 71 and the lower mirror 6. As shown in FIG. 19, the path A passes through the wedge substrate 8 twice, and the path B passes through the wedge substrate 8 four times. Accordingly, the change in the angle of the path B due to the insertion of the wedge substrate 8 is twice the change in the angle of the path A due to the insertion of the wedge substrate 8. Accordingly, in the display device 21 of FIG. 19, the angle 251 of the first reflected beam is changed by δ ′ by the insertion of the wedge substrate 8, and the angle 261 of the second reflected beam is an angle of 2δ ′ by the insertion of the wedge substrate 8. Change occurs.

FIG. 20 shows a state in which the wedge substrate 8 is rotated about the wedge substrate normal 30 as the rotation axis. When the wedge substrate 8 is rotated, the angle 251 of the first reflected beam draws a locus 33 of the angle of the first reflected beam having a radius δ ′ with the point before the wedge substrate 8 is inserted as the center. The angle 261 of the second reflected beam draws a locus 34 of the angle of the second reflected beam having a radius 2δ ′ with the point before the wedge substrate 8 is inserted as the center. Here, as described above, δ ′ is expressed by Expression (25), where α ′ is the angle of the wedge substrate 8 and n is the refractive index.

δ ′ = (n−1) · α ′ Formula (25)

And the center of said two circular-arc locus | trajectories 33 and 34 is calculated by the method similar to 1st Embodiment. Assuming that the centers of the calculated arc trajectories 33 and 34 are (a1, b1) and (a2, b2), respectively, the x component of the angle difference between the angle 251 of the first reflected beam and the angle 261 of the second reflected beam, The y component is calculated by equations (26) to (27), respectively.

Δθx = a2-a1 Formula (26)
Δθy = b2-b1 Formula (27)

Δθx and Δθy according to the equations (26) to (27) correspond to the x component and the y component of the angle difference between the first measured surface 3 and the second measured surface 4, respectively.

  Further, similarly to steps S18 to S21 of the first embodiment, the measurement by the second parallelism measurement method of the first measured surface 3 and the second measured surface 4 and the measurement based on Δθx and Δθy. By repeating the adjustment based on the result, parallelism within a desired accuracy can be obtained.

  As described above, according to the fourth embodiment, even when the wedge substrate 8 is inserted between the beam splitter 71 on the opposite side of the first embodiment and the second measured surface 4, the second With this parallelism measurement method, it is possible to perform highly accurate measurement and adjustment, and the same effects as in the first embodiment can be obtained.

(Fifth embodiment)
Next, a fifth embodiment will be described with reference to FIG. FIG. 21 is a diagram illustrating a parallelism measuring method according to the fifth embodiment. The difference of the fifth embodiment from the first embodiment is that a plate-type beam splitter 72 is used. Since other points are the same as those of the first embodiment, a duplicate description is omitted.

  The reflecting member is not limited to the cube-type beam splitter 71, and may be any member that has a function of a semi-transmissive member that reflects part of incident light and transmits part of the incident light. For example, a plate-type beam splitter 72 is applicable. is there. Even when the plate-type beam splitter 72 shown in FIG. 21 is used, it is possible to adjust the parallelism based on the first parallelism measurement method, the second parallelism measurement method, and each measurement method.

  The plate-type beam splitter 72 is obtained by evaporating a suitable optical thin film as a semi-transmissive member (45-degree surface) 10 on a thin flat glass. The plate-type beam splitter 72 has the following merits not found in the cube-type beam splitter 71 of FIG. That is, since a thin flat glass is employed, it is lightweight, can be manufactured in a relatively large size, and is inexpensive. When the cube beam splitter 71 is used, it is possible to reduce the reflected light path by coating the surfaces 11 and 12 in FIG. However, there is a problem that the coating of the antireflection film is expensive. On the other hand, in the case of the plate-type beam splitter 72, since the surfaces 11, 12 and the like of the cube-type beam splitter 71 do not exist, the coating of the antireflection film becomes unnecessary, and the cost can be reduced.

  As described above, according to the fifth embodiment, even when the plate-type beam splitter 72 is used, the same effect as that of the first embodiment can be obtained and measurement can be performed with a lower cost configuration. The effect that it is is acquired.

  The present invention can be applied when measuring the parallelism of two opposing surfaces with high accuracy. For example, in a manufacturing process of bonding a semiconductor chip on a substrate, it is required to hold two joint surfaces in parallel with extremely high accuracy. However, by applying the measurement method according to the present invention, the parallelism between the two joint surfaces can be increased. It is possible to maintain a desired parallelism by measuring and performing adjustment based on the measurement result.

  Note that, within the scope of the entire disclosure (including claims and drawings) of the present invention, the embodiments can be changed and adjusted based on the basic technical concept. Various combinations or selections of various disclosed elements (including each element of each claim, each element of each embodiment, each element of each drawing, etc.) are possible within the scope of the claims of the present invention. . That is, the present invention naturally includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the drawings, and the technical idea. In particular, with respect to the numerical ranges described in this document, any numerical value or small range included in the range should be construed as being specifically described even if there is no specific description.

1: First device 2: Second device 3: First measured surface 4: Second measured surface 5: Upper mirror (first measured surface)
6: Lower mirror (second measured surface)
8: Wedge substrate 10: 45 degree surface (semi-transmissive member)
11, 12: Surface 20: Autocollimator 21: Display device 22: Computing device 23: Storage device 24: Incident light beam 25: First reflected beam 26: Second reflected beam 30: Normal to the wedge substrate 31: Second reflection Beam angle trajectory centers 32 and 34: second reflected beam angle trajectory 33: first reflected beam angle trajectory 42: return light 60: semiconductor laser 61: first collimator lens 62: beam splitter 63: measured Surface 64: Second collimator lens 65: CCD
66: Light beam 67: Collimated light 68: Reflected collimated light 69: Condensed light 71: Cube-type beam splitter (beam splitter) (reflective member)
72: Plate type beam splitter (reflective member)
101: Suction head 201: Board 251: First reflected beam angle 261: Second reflected beam angle

Claims (10)

A method of measuring parallelism between a first measured surface that is light reflective and a second measured surface that is light reflective using a reflective member,
The reflective member includes a semi-transmissive member, and has a property of reflecting a part of incident light and transmitting a part thereof;
Disposing the surface of the semi-transmissive member of the reflective member so as to be at an angle of approximately 45 degrees with respect to the second measured surface;
An incident light beam is reflected at the interface of the semi-transmissive member of the reflective member, then reflected at the second surface to be measured, reflected again at the interface of the semi-transmissive member of the reflective member, and returned to the incident direction. Measuring the angle of the beam;
The incident light beam is reflected at the interface of the semi-transmissive member of the reflective member, then reflected by the second measured surface, then transmitted through the semi-transmissive member of the reflective member, and then reflected by the first measured surface. The second reflected beam is transmitted again through the semi-transmissive member of the reflective member, reflected again at the second measured surface, and reflected at the interface of the semi-transmissive member of the reflective member to return to the incident direction. Measuring the angle; and
Calculating an angle difference between the first measured surface and the second measured surface from the angles of the first and second reflected beams;
A parallelism measurement method comprising:   Based on the calculated angle difference between the first measured surface and the second measured surface, the angle of the first reflected beam and the angle of the second reflected beam coincide with each other. The parallelism measuring method according to claim 1, further comprising a step of adjusting the parallelism with the second measured surface. Inserting a wedge substrate between the reflecting member and the first surface to be measured;
Rotating the wedge substrate around the normal of the wedge substrate as a rotation axis to change the angle of the second reflected beam, and calculating the locus center of the changed angle of the second reflected beam;
Calculating an angle difference between the first measured surface and the second measured surface from the locus center of the angle of the first reflected beam and the angle of the second reflected beam;
The parallelism measuring method according to claim 1 or 2, further comprising: Inserting a wedge substrate between the reflecting member and the second measured surface;
The angle of the first reflected beam and the angle of the second reflected beam are changed by rotating the wedge substrate about the normal line of the wedge substrate as a rotation axis, and the changed angle of the first reflected beam and the second reflected beam are changed. Calculating the locus center of each of the beam angles;
Calculating an angle difference between the first measured surface and the second measured surface from the respective locus centers of the angle of the first reflected beam and the angle of the second reflected beam;
The parallelism measuring method according to claim 1 or 2, further comprising: A method of measuring parallelism between a first measured surface that is light reflective and a second measured surface that is light reflective using a reflective member and a wedge substrate,
The reflective member includes a semi-transmissive member, and has a property of reflecting a part of incident light and transmitting a part thereof;
Disposing the surface of the semi-transmissive member of the reflective member so as to be at an angle of approximately 45 degrees with respect to the second measured surface;
Inserting the wedge substrate between the reflecting member and the first surface to be measured;
An incident light beam is reflected at the interface of the semi-transmissive member of the reflective member, then reflected at the second surface to be measured, reflected again at the interface of the semi-transmissive member of the reflective member, and returned to the incident direction. Measuring the angle of the beam;
The incident light beam is reflected at the interface of the transflective member of the reflective member, then reflected at the second surface to be measured, then transmitted through the transflective member of the reflective member, then transmitted through the wedge substrate, and Reflected at the first measured surface, again transmitted through the wedge substrate, again transmitted through the semi-transmissive member of the reflecting member, reflected again at the second measured surface, and the semi-transmissive member of the reflecting member. Measuring the angle of the second reflected beam reflected at the interface and returning to the incident direction;
Rotating the wedge substrate around the normal of the wedge substrate as a rotation axis to change the angle of the second reflected beam, and calculating the locus center of the changed angle of the second reflected beam;
Calculating an angle difference between the first measured surface and the second measured surface from the locus center of the angle of the first reflected beam and the angle of the second reflected beam;
Parallelism measurement method including A method of measuring parallelism between a first measured surface that is light reflective and a second measured surface that is light reflective using a reflective member and a wedge substrate,
The reflective member includes a semi-transmissive member, and has a property of reflecting a part of incident light and transmitting a part thereof;
Disposing the surface of the semi-transmissive member of the reflective member so as to be at an angle of approximately 45 degrees with respect to the second measured surface;
Inserting the wedge substrate between the reflective member and the second measured surface;
The incident light beam is reflected at the interface of the semi-transmissive member of the reflective member, then transmitted through the wedge substrate, then reflected by the second surface to be measured, again through the wedge substrate, and again through the semi-transmissive member. Measuring the angle of the first reflected beam reflected at the interface of the transmissive member and returning to the incident direction;
The incident light beam is reflected at the interface of the semi-transmissive member of the reflective member, then transmitted through the wedge substrate, then reflected at the second measured surface, again through the wedge substrate, and then through the reflective member. Transmits through the semi-transmissive member, then reflects at the first measured surface, transmits again through the semi-transmissive member of the reflective member, transmits again through the wedge substrate, reflects again at the second measured surface, and again Measuring the angle of a second reflected beam that is transmitted through the wedge substrate and reflected back at the interface of the transflective member of the reflective member back to the incident direction;
The angle of the first reflected beam and the angle of the second reflected beam are changed by rotating the wedge substrate about the normal line of the wedge substrate as a rotation axis, and the changed angle of the first reflected beam and the second reflected beam are changed. Calculating the locus center of each of the beam angles;
Calculating an angle difference between the first measured surface and the second measured surface from the respective locus centers of the angle of the first reflected beam and the angle of the second reflected beam;
Parallelism measurement method including   The method further includes the step of adjusting the parallelism between the first measured surface and the second measured surface so that the locus center of the angle of the second reflected beam matches the angle of the first reflected beam. 7. The parallelism measuring method according to 3 to 6. A determination step of determining whether or not an angle difference between a trajectory center of an angle of the second reflected beam and an angle of the first reflected beam is within a predetermined threshold;
When it is determined that the angular difference is not within the predetermined threshold,
Adjusting the parallelism between the first measured surface and the second measured surface so that the locus center of the angle of the second reflected beam matches the angle of the first reflected beam;
Rotating the wedge substrate around the normal of the wedge substrate as a rotation axis to change the angle of the second reflected beam, and calculating the locus center of the changed angle of the second reflected beam;
Calculating the angle difference between the angle of the first reflected beam and the locus center of the angle of the second reflected beam;
The determination step;
The parallelism measuring method according to claim 3, wherein the method is repeated.   The parallelism measurement method according to claim 1, wherein the reflecting member is a cube-type beam splitter or a plate-type beam splitter.   The parallelism measurement method according to any one of claims 1 to 9, wherein the angle of the first and second reflected beams is measured using an autocollimator.

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