JP2013117066A - Optical path forming device and imaging device having the same, displacement measuring device and detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical path forming device which forms an optical path for optically connecting the outside of a vacuum processing chamber to an object in the vacuum processing chamber.SOLUTION: The optical path forming device includes: a glass rod 62a inserted into a partition wall 12 defining the vacuum processing chamber 10 via a sealing means 63, which is a base for forming a first optical path P1 linearly extending from the outside of the vacuum processing chamber; and a trapezoidal prism 62b connected to the tip of the glass rod, which is an objective part for forming second optical paths P2, P3 directed to the objective part Wm by bending or curving at least once to the first optical path in which the trapezoidal prism is rotatably configured in rotation around the first optical path in the vacuum processing chamber.

Description

  The present invention relates to an optical path forming device that forms an optical path that optically connects an outside of a vacuum processing chamber and an object existing in the vacuum processing chamber, and an imaging device, a displacement measuring device, and a detection device including the optical path forming device.

  In the manufacturing process of an FPD or a semiconductor device, a vacuum processing apparatus that performs various processes on a substrate surface in a processing chamber is used. In this type of vacuum processing apparatus, when forming a film in a predetermined pattern, for example, on the surface of a substrate in a processing chamber, it is common to use an imaging device to align the substrate with a mask that limits the film formation range. is there. In Patent Document 1, when a mask and a substrate are aligned in a processing chamber provided with an evaporation source in a vacuum deposition apparatus, an imaging unit such as a CCD camera is provided outside a partition wall of a vacuum chamber that defines the processing chamber. An imaging device that images a mask through a substrate by an imaging means is disclosed. In addition, such an imaging apparatus observes the state (posture) of components arranged in a processing chamber, observes the state of a film formed on a substrate, or identifies a film formation target (a workpiece such as a substrate). It is expected to be used for

  By the way, in the above conventional example, since the optical path extends along the optical axis of the imaging optical system of the imaging means, components such as components on the optical axis and elements such as alignment marks formed on the substrate (hereinafter referred to as “ There is a problem that only the “object to be imaged” can be imaged. For example, if there is an opaque obstacle on the optical axis of the imaging optical system, for example, the substrate is an opaque substrate such as a silicon wafer, the imaging object that becomes a blind spot due to the obstacle is optically connected to the imaging optical system. Since it is not attached, it is not possible to image the imaging object.

  On the other hand, in the vacuum deposition apparatus, a displacement measuring means such as a displacement sensor is provided outside the partition wall of the vacuum chamber, and the substrate surface (hereinafter referred to as “measuring object”) in a state where the substrate is held in the processing chamber. It is conceivable to measure the displacement, that is, the film thickness of the thin film formed on the surface of the substrate. However, since the optical path extends along the optical axis of the measuring optical system of the displacement measuring means in the same manner as the imaging device, the optical axis If there is an obstacle on the top, the measurement object and the measurement optical system are not optically linked, and thus the film thickness of the measurement object cannot be measured.

  In such a case, it is conceivable to change the positions of the imaging means and the displacement measuring means so that the imaging object and the measurement object existing in the processing chamber do not become blind spots. However, since many components such as a gas supply system are provided outside the partition wall of the vacuum chamber, the positions of the imaging means and the displacement measuring means cannot be changed so that the imaging object and the measurement object do not become blind spots. There is a case. It is also conceivable to place an imaging means and a displacement measuring means between the mask and the evaporation source in the processing chamber of the vacuum evaporation apparatus, but the imaging means and the displacement measuring means are affected by the heat of the evaporation source during film formation. In addition, it is necessary to prevent the evaporation material from the evaporation source from adhering to the imaging means during film formation. For this reason, a mechanism for retracting the image pickup means and the displacement measurement means from the image pickup position and the measurement position, a heat shield mechanism, and the like are separately required at the time of film formation, and there is a problem that the apparatus configuration becomes complicated and the cost increases.

JP 2002-241924 A

  In view of the above points, the present invention provides an optical path forming device capable of forming an optical path that optically connects an outside of a vacuum processing chamber and an object existing in the vacuum processing chamber, an imaging device including the optical path forming device, a displacement measuring device, and a detection device. It is an object to provide an apparatus.

  In order to solve the above-described problems, the present invention provides an optical path forming apparatus that forms an optical path that optically connects an outside of a vacuum processing chamber and an object existing in the vacuum processing chamber, and defines the vacuum processing chamber. Inserted into a partition wall through a sealing means, and connected to a base part forming a first optical path extending linearly from the outside of the vacuum processing chamber, and a tip of the base part, and at least with respect to the first optical path And an objective part that forms a second optical path that bends or curves once and directs the object, and the objective part is configured to be rotatable around the first optical path in the vacuum processing chamber. And

  According to the present invention, the first optical path is formed by the base, the second optical path that is bent or curved at least once with respect to the first optical path and is directed to the object is formed by the objective, and the first Since the objective part is rotatable around the optical path, if the second optical path from the objective part is aligned with the object by rotating the base part, the outside of the vacuum processing chamber and the object in the vacuum processing chamber are optically connected. It becomes possible to connect.

  In the present invention, it is preferable to connect a trapezoidal prism constituting the objective part to the end of the glass rod constituting the base part. Thereby, the first and second optical paths can be formed with a simple configuration. Furthermore, the incident area of the reflected light in the trapezoidal prism is wider than that in the optical fiber when the optical path forming device is configured with an optical fiber, for example. For this reason, when the optical path forming device of the present invention is used for an imaging device, imaging of an object existing in the processing chamber can be performed over a wide range and with high accuracy.

  In the present invention, the objective unit includes a branching unit that branches the second optical path into a plurality of parts, and each of the second optical paths branched by the branching unit is directed to a different part of the object. Can be configured.

  An imaging apparatus according to the present invention for imaging an imaging object existing in a vacuum processing chamber includes the optical path forming device, includes an imaging optical system disposed outside the partition, and the base portion is on the optical axis of the imaging optical system. The first optical path extending along the optical path is formed, and reflected light from the imaging object is guided to the imaging optical system by the optical path forming device.

  According to the present invention, when the base of the optical path forming device is rotationally driven and the second optical path from the objective unit is matched with the imaging target, the imaging optical system disposed outside the partition wall and the imaging existing in the vacuum processing chamber An object can be optically linked. That is, the reflected light from the imaging target can be guided to the imaging optical system via the second and first optical paths. As a result, it is possible to image an imaging object that does not exist on the optical axis of the imaging optical system. Then, when the imaging device of the present invention is applied to, for example, a vacuum deposition apparatus, the base can be rotated and the objective unit can be directed to a position where the evaporation material from the deposition source is difficult to adhere. A mechanism for evacuating from the apparatus becomes unnecessary, the apparatus configuration can be simplified, and the cost can be reduced.

  An imaging device of the present invention for imaging different locations of an imaging target in a vacuum processing chamber includes an optical path forming device having the branching means, further including an imaging optical system disposed outside the partition, and the base portion The first optical path extending along the optical axis of the imaging optical system is formed, and reflected light from a plurality of locations of the imaging target is guided to the imaging optical system via the first and second optical paths. It is characterized by that.

  According to the present invention, when the base portion of the optical path forming device is rotationally driven to direct each of the second optical paths to different portions of the imaging object, the imaging optical system disposed outside the partition wall and the imaging object Different locations can be optically linked. Accordingly, it is possible to guide reflected light from a plurality of locations of the imaging target to the imaging optical system via the second and first optical paths, and it is possible to capture a plurality of locations of the imaging target.

  A displacement measuring device of the present invention comprising the above optical path forming device, which measures the displacement of a measurement object existing in a vacuum processing chamber, comprising a measuring optical system disposed outside the partition wall, wherein the base is A first optical path extending along the optical axis of the measurement optical system is formed, and reflected light from a measurement object is guided to the measurement optical system by the optical path forming device.

  According to the present invention, when the base of the optical path forming device is rotationally driven and the second optical path from the objective unit is aligned with the measurement object, the measurement optical system disposed outside the partition and the measurement existing in the vacuum processing chamber An object can be optically linked. That is, the reflected light from the measurement object can be guided to the measurement optical system via the second and first optical paths. As a result, the displacement of the measurement object that does not exist on the optical axis of the measurement optical system can be measured. When the displacement measuring apparatus of the present invention is applied to, for example, an etching apparatus or a vacuum evaporation apparatus, the film thickness after etching of the thin film formed on the substrate surface that does not exist on the optical axis of the measuring optical system or the film surface is formed. The film thickness of the thin film can be measured. In addition, when the substrate is aligned with the mask and deposited in a predetermined pattern on the surface of the substrate with a vacuum deposition apparatus, the distance between the substrate and the mask that does not exist on the optical axis of the measurement optical system can be measured. . When applied to a vacuum evaporation system, the base can be rotated to direct the objective to a position where the evaporation material from the evaporation source is difficult to adhere, eliminating the need for a mechanism to retract the displacement measurement device from the displacement measurement position. The apparatus configuration can be simplified and the cost can be reduced.

  A detection device according to the present invention having at least two optical path forming devices as described above, which detects the state of a detection object existing in a vacuum processing chamber, and a light projecting optical system and a light receiving optical device arranged outside the partition wall A first optical path extending along the optical axis of the light projecting optical system, and a base part of the other optical path forming device along the optical axis of the light receiving optical system. A first optical path extending is formed, and the light projected from the light projecting optical system is guided to the light receiving optical system via the one and other light path forming devices.

  According to the present invention, if the respective base portions of one and other optical path forming devices are rotationally driven so that the objective portions face each other, the light projected from the light projecting optical system is emitted from the objective portion of the one optical path forming device. The emitted light is emitted from an objective part of another optical path forming device and enters a light receiving optical system. The amount of light incident on the light receiving optical system changes according to the position or orientation of the measurement object existing between both objectives. For this reason, it is possible to detect the state of the measurement object such as the position and orientation of the measurement object existing between the two object parts and the moving speed of the measurement object moving between the two object parts.

The schematic diagram which shows the imaging device provided with the optical path formation apparatus of 1st Embodiment of this invention. FIG. 2 is an enlarged view of a part of the imaging apparatus illustrated in FIG. 1. The figure which shows the modification of an imaging device. The schematic diagram which shows the displacement measuring apparatus provided with the optical path formation apparatus of 2nd Embodiment of this invention. The schematic diagram which shows the detection apparatus provided with the optical path formation apparatus of 3rd Embodiment of this invention. (A) And (b) is a figure which shows the modification of an optical path formation apparatus. The schematic diagram which shows the imaging device provided with the optical path formation apparatus of 4th Embodiment of this invention. (A) And (b) is a figure for demonstrating the alignment method using the imaging device shown in FIG.

  Hereinafter, with reference to the drawings, a substrate to be processed is a silicon wafer (hereinafter referred to as “wafer”) W, and a vacuum processing apparatus forms a metal film such as copper or aluminum on the surface of the wafer W by vacuum deposition. A vacuum deposition apparatus will be described as an example in which the imaging apparatus having the optical path forming apparatus according to the first embodiment of the present invention is applied to the vacuum deposition apparatus.

  As shown in FIG. 1, the vacuum evaporation apparatus EM1 includes a cylindrical vacuum chamber 1 that defines a vacuum processing chamber (hereinafter referred to as “processing chamber”) 10. A vacuum pump (not shown) is connected to the vacuum chamber 1 via an exhaust pipe 11, and the inside of the vacuum chamber 1 can be held at a predetermined pressure. The upper portion of the vacuum chamber 1 is formed to have a smaller diameter than the lower portion thereof, whereby a horizontal step portion 12 is formed on the side wall of the vacuum chamber 1. The upper space 13a in the vacuum chamber 1 is provided with a stage 2 in which an electrostatic chuck electrode (not shown) is embedded on the lower surface. A predetermined voltage is applied between the electrodes from a chuck power source (not shown), and the wafer W can be attracted by the electrostatic force generated between the electrodes. A drive shaft 31 (one in this embodiment) is connected to the upper surface of the stage 2, and the other end of the drive shaft 31 extends to the outside through a bellows 32 provided on the upper surface of the vacuum chamber 1. The XYθ stage 33 is connected to the structure. The XYθ stage 33 allows the stage 2 suspended by the drive shaft 31 to move in at least one of the X direction and the Y direction in the upper space 13a under vacuum and to rotate in the θ direction. Note that a drive source such as an air cylinder may be separately provided on the drive shaft 31 so as to be movable in the Z direction (up and down direction in FIG. 1).

  In the lower space 13 b in the vacuum chamber 1, the evaporation source 4 is disposed so as to face the lower surface of the stage 2. The evaporation source 4 includes a crucible 42 in which an evaporation material 41 selected according to a thin film to be deposited on the wafer W is stored, and a heating unit 43 such as a heater or an electron gun for evaporating the evaporation material 41. Further, between the stage 2 and the evaporation source 4, there is provided a mask support 5 that supports a mask M that is circular in plan view, for example, which limits the film forming range on the wafer W.

  The mask support 5 includes an annular support plate 50 disposed in parallel with the wafer W and two support columns 51 that suspend the support plate 50. The central opening 52 of the support plate 50 substantially coincides with the contour of the mask M, and an extending portion 53 extending inwardly is formed at the peripheral edge of the lower end thereof. When the mask M is dropped into the central opening 52, The mask M is positioned and supported by the extending portion 53. The mask M has a diameter larger than the diameter of the wafer W, and has various forms according to the film forming range on the wafer W. Further, when the mask M is positioned and supported by the mask support 5, a through hole Mm is formed at a predetermined position on the peripheral edge of the mask M so as to be positioned on an optical path P <b> 3 from a trapezoidal prism 62 b described later. The through holes Mm serve as mask alignment marks when the wafer W is aligned with the mask M.

  The vacuum deposition apparatus EM1 includes an imaging device 6 that images the alignment mark Wm of the wafer W that is an imaging target in the processing chamber 10. The imaging device 6 includes an imaging means 61, an optical path forming device 62, a vacuum sealing means 63, and a driving means described later. The imaging means 61 is provided above (outside) the stepped portion 12 that defines the processing chamber 10, and includes a light source 61 a that emits visible light, laser light having a predetermined wavelength, and the like, and an imaging element 61 b such as a CCD image sensor. And an imaging optical system (not shown) that guides the light emitted from the light source 61a to the glass rod 62a and guides the reflected light from the imaging target W to the imaging device 61b, and is integrally assembled to the housing 61c. .

  The optical path forming device 62 includes a glass rod 62a as a base and a trapezoidal prism 62b as an objective connected to the lower end of the glass rod 62a protruding into the processing chamber. As the glass rod 62a, a known one such as a two-layer structure composed of a core and a clad is used, and a first optical path P1 extending linearly from the outside of the processing chamber 10 along the optical axis Pa of the imaging optical system. Is inserted into the stepped portion 12 via the vacuum sealing means 63. As the trapezoidal prism 62b, a publicly known one such as optical glass or sapphire made of a metal film welded to a slope is used, and the second optical path bent with respect to the first optical path P1 (optical axis Pa). P2 and P3 are formed. That is, for example, the light that has passed through the optical path P1 is guided in the horizontal direction perpendicular to the optical axis Pa of the imaging optical system on one side of the trapezoidal prism 62b (the side connected to the glass rod 62a). The light passing through the optical path P2 is guided further on the other side in parallel with the optical axis Pa to form an optical path P3 between the other side of the trapezoidal prism 62b and the imaging object W. In the present embodiment, the length of the trapezoidal prism 62b is sized so that the optical path P3 extends upward through the through hole Mm.

  As the vacuum sealing means 63, a known structure that rotatably supports the glass rod 62a can be used. Referring to FIG. 2, the vacuum sealing means 63 includes a cylindrical portion 63a having a radially extending flange at the lower end, and two bearings 63b arranged at predetermined intervals in the vertical direction within the cylindrical portion 63a. The permanent magnet 63c disposed between the bearings 63b and a hollow rotating shaft 63d that is rotatably supported by the bearings 63b. A magnetic fluid O-ring (not shown) is formed on the outer surface of the rotating shaft 63d by the magnetic field formed by the permanent magnet 63c. The glass rod 62a is inserted through the hollow portion of the rotating shaft 63d, and the space between the rotating shaft 63d and the glass rod 62a is sealed by an O-ring 63e.

  The driving means 64 includes a housing 64a, a motor 64b disposed on the upper surface of the housing 64a, a driving gear 64d connected to the rotating shaft 64c of the motor 64b, and a driven gear 64e connected to the driving gear 64d. It is configured. A glass rod 62a and a rotating shaft 63c are engaged with the driven gear 64e. According to such a configuration, when the motor 64b is rotationally driven, the drive gear 64d rotates integrally with the rotary shaft 64c, and the rotational force of the drive gear 64d is transmitted to the driven gear 64e to rotate, whereby the optical axis Pa. The glass rod 62a and the rotating shaft 63c rotate by a predetermined amount around the center.

  The imaging means 61 is disposed on the upper surface of the casing 64a, and a through hole 64f is formed in the upper wall of the casing 64a immediately below the imaging means 61. And the vacuum seal means 63 and the drive means 64 are assembled | attached so that the upper end of the glass rod 62a may be located inside this through-hole 64f. According to this, even if the glass rod 62a rotates, the light emitted from the imaging means 61 can be guided to the glass rod 62a, and the light emitted from the upper end of the glass rod 62a can be used as the imaging optical system of the imaging means 61. Can lead to.

  Instead of the driving unit 64, a driving unit 640 shown in FIG. 3 may be used. The driving means 640 includes a driven gear 641 having a height higher than that of the driven gear 64e, and the upper portion of the driven gear 641 passes through the upper wall of the housing 64a. A concave portion 641a is formed in the upper portion of the driven gear 641, and the imaging means 61 is positioned with respect to the glass rod 62a by fitting the lower portion of the imaging means 61 into the concave portion 641a. According to this, when the driven gear 641 rotates, the glass rod 62a, the rotating shaft 62c, and the imaging means 61 rotate by a predetermined amount around the optical axis Pa as the rotation center. A recessed portion 641b having a smaller diameter than the recessed portion 641a is formed below the recessed portion 641a. By positioning the upper end of the glass rod 62a inside the recessed portion 641b, the light from the imaging means 61 can be guided to the glass rod 62a. In addition, the light from the glass rod 62a can be guided to the imaging optical system of the imaging means 61.

  Instead of using the drive gear and the driven gear, a motor rotating shaft and a rotating shaft are connected using a belt, and the motor is driven to rotate to rotate the glass rod 62a around the optical axis Pa as the center of rotation. Also good.

  The image sensor 61b is provided with an image processing means 7, and image data processed by the image processing means 7 is input to the control unit C. The control unit C is a known unit including a microcomputer, a storage element, a sequencer, and the like, and comprehensively controls the operations of the light source 61a, the imaging element 61b, the imaging optical system, the motor 64b, the XYθ stage 33, the heating means 43, and the like. It can be done. Hereinafter, alignment of the wafer W with respect to the mask M using the imaging device 6 of the present embodiment will be described.

  In a state where the vacuum chamber 1 is evacuated and depressurized to a predetermined pressure, the mask M is transferred by a vacuum transfer robot (not shown), and the mask M is set in the central opening 52 of the support plate 50 of the mask support 5. In the mask M, through-holes that are alignment marks Mm are formed at intervals of 180 degrees in the circumferential direction. Next, the wafer W is transferred by a vacuum transfer robot (not shown), and the wafer W is attracted to the stage 2 with its film formation surface facing downward. In this case, alignment marks Wm having a smaller diameter (for example, φ0.5 mm) than the alignment mark Mm of the mask M are provided on the outer peripheral edge portion of the film formation surface of the wafer W at intervals of 180 degrees in the circumferential direction.

  After adsorbing the wafer W, the motor 64b is driven to rotate the glass rod 62a so that the tip of the trapezoidal prism 62b is positioned below the alignment mark Wm of the wafer W, that is, the optical path P3 from the trapezoidal prism 62b is set. Align with the alignment mark Wm on the wafer W (imaging position). When light is irradiated from the light source 61a, the light is irradiated onto the wafer W through the optical paths P1, P2, and P3. The reflected light from the wafer W is guided to the imaging optical system of the imaging means 61 through the optical paths P3, P2, and P1, and formed on the light receiving surface of the imaging element 61b by the imaging optical system. As a result, the alignment mark Wm of the wafer W that does not exist on the optical axis Pa of the imaging optical system of the imaging means 61 is imaged through the mask M. The image picked up by the image pickup means 61 is sent to the image processing means 7, and the image processing means 7 performs image processing to detect the shift amount of the wafer W with respect to the mask M. The detected shift amount is input to the control unit C, and the movement amount of the XYθ stage 33 is calculated based on the input shift amount, and the stage 33 is moved in at least one of the X direction and the Y direction, or the θ direction. , The orientation of the wafer W is changed and alignment is performed.

  When the alignment is completed, the glass rod 62b is rotated by a predetermined amount (for example, 180 degrees), and the tip of the trapezoidal prism 62b hardly adheres to the evaporation material from the evaporation source 4 as indicated by a two-dot chain line in FIG. It is located near the side wall of the vacuum chamber 1 (retracted position). Then, the heating means 43 is operated to evaporate the evaporation material 41 in the crucible 42 and form a film on the wafer W in a predetermined pattern.

  As described above, according to the imaging apparatus of the present embodiment, the optical path necessary for imaging the alignment mark Wm is formed by the glass rod 62a and the trapezoidal prism 62b, and the trapezoidal prism with the first optical path P1 as the rotation center. Since the glass rod 62a is driven to rotate so that the optical path P3 from the trapezoidal prism 62b is directed to the alignment mark Wm, the image pickup means 61 outside the processing chamber 10 and the alignment mark Wm in the processing chamber 10 are optically driven. Optical paths P1 to P3 are formed. In other words, the reflected light from the alignment mark Wm can be guided to the imaging optical system of the imaging means 61 via the optical paths P1 to P3. As a result, the alignment mark Wm of the wafer W that does not exist on the optical axis Pa of the imaging optical system of the imaging means 61 can be imaged. In addition, since the trapezoidal prism 62b can be retracted by rotating the glass rod 62a before the film forming process, the material evaporated from the evaporation source 4 becomes difficult to adhere to and accumulate on the tip of the trapezoidal prism 62b. It is difficult to cause a problem that the tip is closed immediately and the alignment mark Wm cannot be imaged by the imaging unit 61. For this reason, there is no need for a mechanism or parts for preventing heat shield or evaporation material from adhering to the imaging means during film formation, not only simplifying the apparatus configuration but also preventing an increase in the number of parts, CCD cameras, etc. In combination with the fact that the inexpensive imaging means 61 can be used, the cost can be reduced.

  In the present embodiment, since the optical path forming device 62 is composed of the glass rod 62a and the trapezoidal prism 62b connected to the end of the glass rod 62a, the optical path forming device 62 can be realized with a simple configuration. By the way, the optical path forming device 62 can be constituted by an optical fiber cable. In this case, for example, a plurality of optical fiber strands having a diameter of 0.125 mm are bundled to form an optical path, and therefore, the cross section of the optical fiber cable 62 other than the cross section of the optical fiber strand becomes a blind spot. When imaging an imaging object that is significantly larger than the blind spot or when imaging an imaging object that is small in the cross section of the optical fiber, it is possible to accurately image the imaging object using the optical fiber cable 62. However, it is not preferable to apply this method when imaging the alignment mark Wm having a diameter of 0.5 mm and performing alignment with an accuracy of 0.5 μm. On the other hand, the incident area of the reflected light in the trapezoidal prism 62b is larger than the incident area of the reflected light in the optical fiber cable, and the blind spot does not occur, so that the alignment mark Wm can be accurately imaged.

  Next, the case where the substrate to be processed is the wafer W, the vacuum processing apparatus is the above vacuum vapor deposition apparatus, and the displacement measuring apparatus having the optical path forming apparatus of the second embodiment of the present invention is applied to this vacuum vapor deposition apparatus as an example. explain.

  A vacuum vapor deposition apparatus EM2 shown in FIG. 4 is different from the vacuum vapor deposition apparatus EM1 in that a displacement measuring device 8 is provided instead of the imaging device 6. The displacement measuring device 8 includes a displacement measuring unit 81, an optical path forming device 62, a vacuum sealing unit 63, and a driving unit 64. The optical path forming device 62, the vacuum sealing means 63, and the driving means 64 are the same as those of the imaging device 6. According to the rotational driving amount of the glass rod 62a, the length of the trapezoidal prism 62b is sized so that the optical path P3 extends to the lower surface Wa of the wafer W through the through hole Mm as a light transmitting portion as shown by a solid line in FIG. ing.

  The displacement measuring means 81 is provided above the stepped portion 12 that defines the processing chamber 10, and guides the light emitted from the light source 81a, the displacement sensor 81b, and the light source 81a to the glass rod 62a and the measurement object W. A measurement optical system (not shown) that guides reflected light from the sensor to the displacement sensor 81b is integrally assembled with the housing 81c. As the displacement sensor 81b, for example, a known one such as a spectral interference type displacement sensor can be used, and therefore, detailed description thereof is omitted here. In the figure, Pa represents the optical axis of the measurement optical system.

  A signal processing means 9 is attached to the displacement sensor 81b, the measurement result of the displacement sensor 81b is stored, the respective surface positions (lower surface positions) of the wafer W and the mask M are obtained from the stored measurement results, and the obtained surface positions are obtained. The distance between the wafer W and the mask M is obtained based on the above, and this distance is input to the control unit C. Further, the signal processing means 9 can obtain the film thickness of the thin film formed on the surface of the wafer W based on the obtained surface position of the wafer W so that the obtained film thickness is input to the control unit C. It has become. The control unit C is a known unit including a microcomputer, a storage element, a sequencer, and the like, and comprehensively controls operations of the light source 81a, the displacement sensor 81b, the measurement optical system, the motor 64b, the XYθ stage 33, the heating means 43, and the like. It can be done. Hereinafter, a method for measuring the distance between the mask M and the wafer W and a method for measuring the thickness of the thin film formed on the surface of the wafer W using the displacement measuring apparatus 8 of the present embodiment will be described.

  Similar to the alignment described above, the mask M is transported into the vacuum chamber 1 whose pressure has been reduced, and is set on the mask support 5. In addition, the wafer W is transferred into the vacuum chamber 1 and is attracted onto the stage 2. After adsorbing the wafer W, the glass rod 62a is rotated and the tip (exit / incident end) of the trapezoidal prism 62b is positioned below the translucent part Mm of the mask M as shown by the solid line in FIG. Position), that is, the optical path P3 from the trapezoidal prism 62b is aligned with the lower surface Wa of the wafer W through the translucent portion Mm. And the light emitted from the displacement measuring means 81 is irradiated toward the translucent part Mm of the mask M through the optical paths P1, P2, and P3. The irradiated light is reflected by the lower surface Wa of the wafer W through the light transmitting part Mm and also reflected by the lower surface Ma of the mask M around the light transmitting part Mm. These reflected lights are guided to the displacement measuring means 81 via the optical paths P3, P2, and P1. Based on the phase difference between the two reflected lights, the position of the lower surface Wa of the wafer W and the position of the lower surface Ma of the mask M are measured.

  Then, the signal processing means 9 calculates the distance from the measured position of the lower surface Wa of the wafer W to the position of the lower surface Ma of the mask M, and subtracts the known thickness of the mask M from the calculated distance. Thereby, the space | interval between the wafer W and the mask M can be calculated | required. The stage 33 may be driven in the Z direction according to the interval thus obtained.

  When the interval measurement is completed, the glass rod 62b is rotated by a predetermined amount (for example, 180 degrees), and the tip of the trapezoidal prism 62b is attached to the evaporation material from the evaporation source 4 as indicated by a two-dot chain line in FIG. It is located in the vicinity of the side wall of the vacuum chamber 1 which is difficult to perform (retract position). Then, the heating means 43 is operated to evaporate the evaporation material 41 in the crucible 42 and form a film on the wafer W in a predetermined pattern.

  After the film formation for a predetermined time, the glass rod 62b is rotated and moved again to the measurement position, and the position of the wafer lower surface Wa is measured again by the method described above. Then, by calculating the difference from the position of the wafer lower surface Wa measured at the time of the interval measurement in the signal processing means 9, the film thickness of the thin film formed on the wafer surface can be obtained.

  As described above, according to the displacement measuring apparatus of the present embodiment, the optical path necessary for the displacement measurement by the displacement measuring means 81 is formed by the glass rod 62a and the trapezoidal prism 62b, and the first optical path P1 is the rotation center. Since the trapezoidal prism 62b is rotatable, if the glass rod 62a is rotated and the optical path P3 from the trapezoidal prism 62b is directed to the wafer W and the mask M, the displacement measuring means 81 outside the processing chamber 10 and the inside of the processing chamber 10 are Optical paths P1 to P3 that optically connect the wafer W and the mask M are formed. That is, the reflected light from the wafer W and the mask M can be guided to the measuring optical system of the displacement measuring means 81 via the optical paths P1 to P3. As a result, the positions of the wafer W and the mask M which do not exist on the optical axis Pa of the measurement optical system of the displacement measuring means 81 can be measured, and the distance between the wafer W and the mask M and the thin film formed on the surface of the wafer W can be measured. The film thickness can be determined. In addition, as with the above-described imaging device, the tip of the trapezoidal prism 62b is closed immediately, and the displacement measuring unit 81 cannot measure the position. For this reason, it is not necessary to provide a mechanism or parts for preventing heat shielding or evaporation material from adhering to the displacement measuring means 81 at the time of film formation, not only simplify the apparatus configuration, but also prevent an increase in the number of parts. Cost can be reduced.

  Next, with reference to FIG. 5, a case where the detection apparatus having the optical path forming apparatus according to the third embodiment of the present invention is applied to a vacuum processing apparatus will be described as an example. The vacuum processing apparatus EM3 is different from the vacuum deposition apparatuses EM1 and EM2 in that the detection apparatus 9 is provided and the trapezoidal prism constituting the optical path forming apparatus 62 is a right-angled trapezoidal prism 62c.

  The detection device 9 includes a light projecting unit 9a and a light receiving unit 9b arranged outside the partition wall 12 of the vacuum chamber 1, an optical path forming device 62 provided corresponding to each of the light projecting unit 9a and the light receiving unit 9b, a vacuum seal Means 63 and the drive means (not shown).

  The light projecting means 9a includes a light source and a light projecting optical system (not shown), and a glass rod 62a of one optical path forming device 62 (on the left side in the figure) extends linearly along the optical axis Pa of the light projecting optical system. A first optical path P11 is formed. The light receiving means 9b includes a light receiving optical system (not shown), and a glass rod 62a of another optical path forming device 62 (on the right side in the drawing) extends linearly along the optical axis Pa of the light receiving optical system. An optical path P14 is formed.

  In the right-angle trapezoidal prism 62c of each optical path forming device 62, a metal film is welded to a slope connected to the glass rod 62a. The right-angle trapezoidal prism 62c of one optical path forming device 62 forms a second optical path P12 that is bent once with respect to the first optical path P11 (optical axis Pa). Similarly, the right trapezoidal prism 62c of the other optical path forming device 62 forms the second optical path P13 bent once with respect to the first optical path P14 (optical axis Pa). When the orthogonal surfaces (surfaces orthogonal to the second optical paths P12 and 13) on which the metal film of the trapezoidal prism 62c is not welded using the driving means 64, the light passing through the optical path P11 is one. Other trapezoidal prisms (on the light receiving means 9b side) that are guided to the horizontal optical path P12 orthogonal to the optical path P11 at the slope of the trapezoidal prism 62c (on the light projecting means 9a side). The light is further guided to the optical path P13 of 62c, guided to the optical path P14 extending upward perpendicularly to the optical path P13 on the slope of the other trapezoidal prism 62c, and guided to the light receiving optical system. At this time, the amount of light guided to the light receiving optical system varies depending on the state of the detection object such as the wafer W arranged between the orthogonal surfaces of the opposed trapezoidal prisms 62c. Further, when the detection object moves between both slopes, the amount of light guided to the light receiving optical system also changes due to the movement.

  The light receiving means 9b is provided with a signal processing means (not shown), stores the amount of light received by the light receiving means 9b, detects the position, posture, movement speed, etc. of the detection object W from the stored light quantity and detects it. The state is input to a control unit (not shown).

  By the way, when forming one second optical path P2 and P3 in the objective part 62b as in the first embodiment, if there is a light shielding member on the second optical path, it is at the tip of the light shielding member. The imaging object cannot be imaged. For example, as shown in FIG. 7, when the alignment mark Wm is provided on the upper surface of the silicon wafer W, when the silicon wafer W is imaged from below, the silicon wafer W serves as a light shielding member to image the alignment mark Wm. Can not. Hereinafter, the case where the vacuum processing apparatus is a vacuum deposition apparatus and the imaging apparatus having the optical path forming apparatus according to the fourth embodiment of the present invention is applied to the vacuum deposition apparatus will be described as an example.

  As shown in FIG. 7, the vacuum deposition apparatus EM4 includes a cylindrical vacuum chamber 1a that defines a processing chamber 10a, and an electrode for an electrostatic chuck (not shown) is provided on the lower surface of the vacuum chamber 1a. A buried stage 2 is provided. The stage 2 is formed with a through hole 21 penetrating in the thickness direction, and the wafer W is held on the stage 2 so that the alignment mark Wm is positioned below the through hole 21. Similarly to the first embodiment, the mask M is supported by the mask support 5 so as to face the stage 2.

  The imaging means 61 includes a light source 61a, a CCD image sensor that is an imaging element 61b, and a telecentric lens that is an imaging optical system (not shown) provided below the imaging element 61b. In the figure, Pa indicates the optical axis of the imaging optical system.

  The optical path forming device 65 includes a glass rod 65a serving as a base and an objective unit 65b connected to the lower end of the glass rod 65a protruding into the processing chamber 10a. The objective part 65b is composed of a frame 66 and a plurality of mirrors 66a to 66g arranged in a predetermined positional relationship inside the frame 66, with respect to the first optical paths P11 and P12 (optical axis Pa). The bent second optical paths P21 and P22 are formed. The frame body 66 includes a base end portion 67 connected to the glass rod 65a and a pair of front end portions 68 and 69 extending from the base end portion 67 in a bifurcated manner.

  According to the above configuration, the light passing through the optical paths P11 and P12 is guided to the horizontal direction orthogonal to the optical axis Pa of the imaging optical system by the mirror 66a provided at the base end portion 67, and the optical path P21a extending in the horizontal direction. The light passing through is guided upward by the mirror 66b to form the optical path P21b, while the light passing through the optical path P22a is guided downward by the mirror 66c to form the optical path P21b. These mirrors 66b and 66c constitute branching means. Then, the light passing through the optical path P21b is guided horizontally by the mirror 66d to form the optical path P21c, and the light passing through the optical path P21c is guided downward by the mirror 66e, and the optical path between the upper end portion 68 and the imaging object W is guided. P21d is formed. Further, the light passing through the optical path P22b is guided horizontally by the mirror 66f to form the optical path P22c, and the light passing through the optical path P22c is guided upward by the mirror 66g, so that the space between the lower end portion 69 and the imaging object M is reduced. An optical path P22d is formed. In the present embodiment, the CCD image sensor 61b is configured to display the image of the alignment mark Wm in the left visual field and simultaneously display the alignment mark Mm in the right visual field. For this reason, the mirrors 66a to 66g are arranged so that the distance from the imaging optical system to the imaging objects Wm and Mm is the same (that is, the work distance is the same). Hereinafter, the alignment of the wafer W with respect to the mask M using the imaging apparatus will be described.

  As in the first embodiment, the mask M is supported by the mask support 5 and the wafer W is attracted to the lower surface of the stage 2. Here, unlike the first embodiment, the alignment mark Wm of the wafer W is formed on the upper surface of the wafer W. Next, the motor 64b is driven to rotate the glass rod 65a to direct the optical path 21d from the tip 68 of the objective 65b to the alignment mark Wm of the wafer W and to the optical path 22d from the tip 69 of the objective 65b. Is directed toward the alignment mark Mm of the mask M (imaging position).

  When light is emitted from the light source 61a, light that has passed through the first optical path P11 and the second optical paths P21a to P21d (hereinafter abbreviated as “P21”) is irradiated onto the upper surface of the wafer W. The reflected light from the wafer W is guided to the imaging optical system via the second optical path P21 and the first optical path P11, and is imaged on one side (left side in the drawing) of the imaging element 61b by the imaging optical system. . At the same time, the light having passed through the first optical path P12 and the second optical paths P22a to P22d (hereinafter abbreviated as “P22”) is irradiated onto the mask M. The reflected light from the mask M is guided to the imaging optical system through the second optical path P22 and the first optical path P12, and is imaged on the other side (right side in the drawing) of the imaging element 61b by the imaging optical system. . As a result, a plurality of locations on the imaging target that do not exist on the optical axis Pa of the imaging optical system of the imaging means 61, that is, the alignment marks Wm and Mm are imaged. The image picked up by the image pickup means 61 is sent to the image processing means 7, and the image processing means 7 performs image processing to detect the shift amount of the wafer W with respect to the mask M. As in the first embodiment, the detected deviation amount is input to the control unit C, the movement amount of the XYθ stage 33 is calculated, the stage 33 is moved in at least one of the X direction and the Y direction, or θ By rotating in the direction, the orientation of the wafer W is changed and alignment is performed.

Here, in the present embodiment, since a plurality of locations are imaged, the displacement amount is detected in consideration of the displacement amount between the left visual field and the right visual field of the imaging means 61b as follows. That is, as shown in FIG. 8A, a calibration mark (for example, an alignment mark formed on a transparent substrate) is imaged from the upper side through the optical path P11 and the optical path P21 and displayed in the left visual field. At the same time, images are taken from below via the optical paths P12 and P22 and displayed in the right field of view. The coordinates (X1, Y1, θ1) of the center of gravity of the mark displayed in the left field of view and the coordinates (X2, Y2, θ2) of the center of gravity of the mark displayed in the right field of view are obtained as relative coordinates, and the obtained center of gravity coordinates are determined by the control unit C. Remember. Then, as shown in FIG. 8B, during actual alignment, the coordinates (X1 ′, Y1 ′, θ1 ′) of the center of gravity of the alignment mark Wm displayed in the left visual field of the imaging means 61b and the alignment displayed in the right visual field. The coordinates (X2 ′, Y2 ′, θ2 ′) of the center of gravity of the mark Mm are obtained. Then, the shift amounts (ΔX, ΔY, Δθ) of both alignment marks Wm, Mm are obtained by the following equations. Note that the method of calculating the deviation amount between the marks Wm and Mm is not limited to this method, and other known methods can be used.
(ΔX, ΔY, Δθ) = {(X1, Y1, θ1) − (X1 ′, Y1 ′, θ1 ′)}
− {(X2, Y2, θ2) − (X2 ′, Y2 ′, θ2 ′)}

  As described above, according to the imaging apparatus of the present embodiment, the second optical path is branched into a plurality (two in the present embodiment), and each of the branched second optical paths is set to different alignment marks Wm, Mm. Therefore, the imaging means 61 disposed outside the processing chamber 10a and the plurality of alignment marks Wm and Mm in the processing chamber 10a can be optically linked. Accordingly, the reflected light from the plurality of alignment marks Wm, Mm can be guided to the imaging means 61 via the second and first optical paths P21, 22, 11, 12, and the imaging objects W, M A plurality of locations Wm and Mm can be imaged. Two imaging elements 61b are provided, and one of them can display the alignment mark Wm and the other can display the alignment mark Mm. However, as in this embodiment, the field of view of one imaging element 61b is divided. As a result, the number of parts can be reduced and the device cost can be reduced. Further, by appropriately setting the position of the mirror including the branching means of the objective unit, it is possible to image a plurality of locations existing on the same plane of the imaging target.

  As mentioned above, although embodiment of this invention was described, this invention is not limited above. In the above-described embodiment, the optical path forming device 62 in which the trapezoidal prism 62b or the trapezoidal prism 62c having the trapezoidal shape or the right-angled trapezoidal shape is connected to the tip of the glass rod 62a has been described as an example. For example, a reflecting mirror can be installed to form an optical path. For example, in place of the trapezoidal prism, another glass rod is installed horizontally, the light from the glass rod 62a is bent by the reflecting mirror and guided to the other glass rod, and the light from the other glass rod is moved upward by the reflecting mirror. You may make it lead to. For example, instead of the trapezoidal prism, an optical fiber that is curved so that one end side is directed to the alignment mark Wm of the substrate W and the other end side is directed to the lower end of the glass rod 62a may be used. Further, for example, as shown in FIG. 6A, a pair of rectangular prisms 62c whose opposite sides are not parallel in a sectional view are connected to the tip of the glass rod 62a, and the optical path P4 is bent once with respect to the optical axis Pa. May be formed. Further, for example, as shown in FIG. 6B, the tip of the glass rod 62a is arranged so that the angle formed by the first optical path P1 in the glass rod 62a and the second optical path P2 in the trapezoidal prism 62b becomes an obtuse angle. A trapezoidal prism 62b may be connected.

  In the above embodiment, the imaging means 61 having the light source 61a is used, but the light source 61a may be omitted when there is a certain level of brightness in the vacuum chamber before the vacuum processing, such as by incorporating a lamp heater. it can. Moreover, in the said embodiment, although the alignment mark Wm is imaged, an imaging target object is not limited to this, For example, the lot number and barcode which were attached | subjected to the wafer can be imaged.

  In the above embodiment, the case where the imaging device or the displacement measuring device including the optical path forming device of the present invention is applied to the vacuum evaporation device has been described as an example. However, the present invention can be applied to a sputtering device, a CVD device, an etching device, or the like. . For example, if a displacement measuring device is applied to the etching apparatus and the displacement of the wafer lower surface Wa is measured by this displacement measuring means, the remaining film after etching of the thin film formed on the wafer surface can be measured.

  DESCRIPTION OF SYMBOLS 1 ... Vacuum chamber (processing chamber), 6 ... Imaging device, 8 ... Displacement measuring device, 9 ... Detection device, 61 ... CCD camera (imaging means), 62 ... Optical path forming device, 62a ... Glass rod (base), 62b, 62c ... Trapezoidal prism (objective part), 63 ... Vacuum sealing means, 66b, 66c ... Mirror (branching means), 81 ... Displacement sensor, Pa ... Optical axis, P1, P11, P12 ... First optical path, P2, P3 P21 (P21a to P21d), P22 (P22a to P22d) ... second optical path, P11 to P14 ... optical path, Wm ... alignment mark (imaging object), Mm ... alignment mark (imaging object).

Claims (7)

An optical path forming device for forming an optical path for optically connecting an outside of a vacuum processing chamber and an object existing in the vacuum processing chamber,
A first base that forms a first optical path extending linearly from the outside of the vacuum processing chamber and is inserted into a partition wall that defines the vacuum processing chamber via a sealing means, and connected to a tip of the base, And an objective part which forms a second optical path which is bent or curved at least once with respect to the optical path and directs the object, and the objective part is rotatable about the first optical path in the vacuum processing chamber. An optical path forming device configured as described above.   2. The optical path forming apparatus according to claim 1, wherein a trapezoidal prism constituting the objective part is connected to an end of a glass rod constituting the base part.   The objective unit has branching means for branching the second optical path into a plurality of parts, and each of the second optical paths branched by the branching means is configured to point to different parts of the object. The optical path forming device according to claim 1. An imaging apparatus comprising the optical path forming device according to claim 1 or 2, wherein an imaging object existing in a vacuum processing chamber is imaged.
An imaging optical system disposed outside the partition; the base portion forming the first optical path extending along the optical axis of the imaging optical system; and the reflected light from the imaging object is reflected by the optical path forming device. An imaging apparatus characterized by being guided to the imaging optical system. An imaging apparatus comprising the optical path forming device according to claim 3, wherein each of the different imaging objects in the vacuum processing chamber is imaged.
An imaging optical system disposed outside the partition wall, wherein the base forms the first optical path extending along the optical axis of the imaging optical system, and the imaging object is provided via the first and second optical paths; An imaging apparatus characterized in that reflected light from different locations is guided to the imaging optical system. A displacement measuring device comprising the optical path forming device according to claim 1, wherein the displacement measuring device measures a displacement of a measurement object existing in a vacuum processing chamber.
A measurement optical system disposed outside the partition wall, wherein the base portion forms a first optical path extending along the optical axis of the measurement optical system, and the reflected light from the measurement object is reflected by the optical path forming device A displacement measuring device characterized by being guided to a measuring optical system. A detection device comprising at least two optical path forming devices according to claim 1 or 2, wherein the detection device detects the state of a detection object existing in a vacuum processing chamber.
A light projecting optical system and a light receiving optical system disposed outside the partition; a base of one optical path forming device forms a first optical path extending along an optical axis of the light projecting optical system; The base of the forming device forms a first optical path extending along the optical axis of the light receiving optical system, and the light projected from the light projecting optical system is passed through the one and other optical path forming devices. A detection device characterized by being guided to a light receiving optical system.

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