JP4867784B2 - POSITION DETECTION DEVICE, WAFER SUPPLY DEVICE, LAMINATED 3D SEMICONDUCTOR DEVICE MANUFACTURING METHOD, EXPOSURE DEVICE, AND DEVICE MANUFACTURING METHOD - Google Patents

Description

  The present invention relates to a precise position detection apparatus applied to a wafer overlay apparatus, an exposure apparatus, and the like. The present invention also relates to a wafer overlay apparatus and exposure apparatus provided with a position detection apparatus, a method for manufacturing a stacked three-dimensional semiconductor device, and a method for manufacturing a device.

  An exposure apparatus used for manufacturing a semiconductor element, a liquid crystal display element or the like is equipped with a position detection apparatus for detecting the position of a substrate mark with high accuracy.

  For example, as disclosed in Patent Document 1, this type of position detection apparatus includes a microscope optical system for magnifying and observing an image of a substrate mark. Focus adjustment on the substrate mark is performed in the direction of the optical axis of the substrate stage. This is done by driving in the (Z direction). Therefore, the optical element in the position detection device does not move during focus adjustment, and there is almost no possibility that an eccentricity or tilt error occurs in the position detection device. For this reason, the detection accuracy of the position detection device is high.

Such a position detection apparatus is considered to be effective for apparatuses other than the exposure apparatus. For example, it is a wafer superposition apparatus described in Patent Document 2.
Japanese Patent Laid-Open No. 11-304422 JP 2005-251972 A

  However, in order to mount the position detection device on the wafer superimposing apparatus and to adjust the focus thereof, each of the stages supporting the two wafers to be superposed must be driven in the Z direction, which is inefficient. .

  Therefore, an object of the present invention is to provide a position detection device having a focus adjustment function and high detection accuracy. Another object of the present invention is to provide a high-performance wafer overlay apparatus and exposure apparatus. Another object of the present invention is to provide a method for manufacturing a stacked three-dimensional semiconductor device capable of manufacturing a high-performance stacked three-dimensional semiconductor device, and a device manufacturing method capable of manufacturing a high-performance device. To do.

Position detecting device of the present invention, there is provided a position detecting device for detecting a position of an object relative to the index, and an imaging lens for forming an image of the object based on the light beam objective lens is captured on the imaging surface, the light beam from the index to be incident to the object side of the imaging lens, and a projection lens for projecting an image of the index on the imaging surface through the imaging lens, the imaging lens in the optical axis direction A focusing mechanism for moving, and a depth of focus of a projection optical system constituted by the projection lens and the imaging lens is larger than a depth of focus of an observation optical system constituted by the objective lens and the imaging lens It is characterized by deepness .

  The numerical aperture on the image side of the projection optical system constituted by the projection lens and the imaging lens is smaller than the numerical aperture on the image side of the observation optical system constituted by the objective lens and the imaging lens. It is desirable.

  Further, it is desirable that the movable range of the imaging lens be within the focal depth of the projection optical system.

  Further, it is desirable that the exit pupil of the objective lens and the exit pupil of the projection lens viewed from the imaging lens are arranged at equivalent positions.

  The position detection device of the present invention may further include a camera that acquires an image of the imaging surface.

  The position detection apparatus of the present invention may further include control means for driving the focusing mechanism so that the contrast of the image of the object is increased based on an image acquired by the camera.

  The position detection apparatus of the present invention may further include a measuring unit that measures a positional relationship between the image of the object and the image of the index based on an image acquired by the camera.

  Further, a wafer overlaying apparatus according to the present invention includes any one of the position detection apparatuses according to the present invention.

  According to another aspect of the present invention, there is provided a method for manufacturing a stacked three-dimensional semiconductor device comprising: a wafer preparation step for preparing a predetermined number of wafers on which a plurality of semiconductor devices are formed; An alignment step for measuring the positional relationship, a wafer superimposing step for superimposing the wafers measured for the positional relationship, an electrode bonding step for laminating the connection electrodes of the superimposed wafers, and laminating the wafers, And a dicing step of cutting out a plurality of stacked three-dimensional semiconductor devices from the predetermined number of stacked wafers, wherein the position detection device according to any one of claims 1 to 7 is used in the alignment step. It is characterized by that.

  An exposure apparatus according to the present invention includes any one of the position detection apparatuses according to the present invention.

  The device manufacturing method of the present invention includes a step of exposing a substrate using the exposure apparatus of the present invention, and a step of developing the exposed substrate.

  According to the present invention, a position detection device having a focus adjustment function and high detection accuracy is realized. Further, according to the present invention, a high-performance wafer overlaying apparatus and exposure apparatus are realized.

  In addition, according to the present invention, a manufacturing method of a stacked three-dimensional semiconductor device capable of manufacturing a high-performance stacked three-dimensional semiconductor device and a manufacturing method of a device capable of manufacturing a high-performance device are realized.

[First Embodiment]
This embodiment is an embodiment of a position detection device. The position detection apparatus according to the present embodiment detects the position in the surface direction (XY direction) of a wafer mark formed in advance on a silicon wafer. Hereinafter, the silicon wafer is simply referred to as “wafer”.

  First, the configuration of the position detection device will be described.

  FIG. 1 is a configuration diagram of a position detection device. As shown in FIG. 1, the position detection apparatus includes an illumination optical system S1, an observation optical system S2, a projection optical system S3, a camera 10 having sensitivity in the visible region to the infrared region, and a control unit (not shown). Prepare.

  The illumination optical system S1 includes an illumination light source 1, a lens 2, a filter 3, a lens 4, a half mirror 5, and an infinite objective lens 6. The observation optical system S2 includes an objective lens 6, a half mirror 5, a half mirror 8, and an imaging lens 9. The half mirror 5 and the objective lens 6 are shared with the illumination optical system S1. The projection optical system S3 includes a projection light source 11, a lens 12, an optical fiber 13, a lens 14, an index 15, a projection lens 16, an aperture stop 17, a half mirror 8, and an imaging lens 9, and includes the half mirror 8 and the imaging lens. The lens 9 is shared with the observation optical system S2.

  The illumination light source 1 of the illumination optical system S1 is a halogen lamp that emits infrared light. The infrared light emitted from the illumination light source 1 is collimated by the lens 2, passes through the filter 3, becomes a parallel light beam by the lens 4, and reflects the half mirror 5. The infrared light reflected from the half mirror 5 is collected by the objective lens 6 and illuminates the wafer mark M1 on the wafer 7 and its periphery. Wafer mark M1 is a two-dimensional pattern (for example, a cross-shaped pattern).

  The infrared light reflected by the wafer mark M1 is captured by the objective lens 6 and condensed toward infinity. The condensed infrared light is sequentially transmitted through the half mirror 5 and the half mirror 8 and then condensed by the imaging lens 9, and an infrared image (hereinafter referred to as “mark”) of the wafer mark M 1 near the imaging surface of the camera 10. Image ").

  The projection light source 11 of the projection optical system S3 is a halogen lamp that emits visible light. The visible light emitted from the projection light source 11 is condensed on the end surface 13a of the optical fiber 13 by the lens 12, and then propagates through the optical fiber 13 and exits from the other end surface 13b. An image (secondary light source) of the projection light source 11 is formed on the end face 13b. The visible light emitted from the secondary light source is collected by the lens 14 and illuminates the indicator 15. The index 15 is a transmission type index as shown in FIG. 1, and a two-dimensional pattern (for example, a cross-shaped pattern) P is formed. The visible light that has passed through the pattern P of the index 15 is captured by the projection lens 16 and condensed toward infinity. The condensed visible light travels toward the half mirror 8 through the aperture stop 17 and reflects off the half mirror 8. The visible light reflected from the half mirror 8 is collected by the imaging lens 9 and forms a visible image of the index 15 (hereinafter referred to as “index image”) on the imaging surface of the camera 10.

  Here, the objective lens 6 is telecentric on the object side. The lens 2 and the lens 4 of the illumination optical system S1 project the image of the illumination light source 1 on the image side focal plane of the objective lens 6, thereby performing Koehler illumination of the wafer mark M1 and its periphery with infrared light.

  The object side focal plane of the imaging lens 9 is disposed at the same position as the image side focal plane of the objective lens 6. Therefore, the observation optical system S2 is double-sided telecentric.

  Further, the position of the imaging lens 9 in the optical axis direction is variable by a drive mechanism (including a motor) (not shown), and the positions of other elements are fixed to each other. However, the projection light source 11, the lens 12, and the end surface 13a of the projection optical system S3 may be displaced as long as their positional relationships are fixed.

  Therefore, even if the object-side focal plane of the observation optical system S2 deviates from the surface of the wafer 7, the object-side focal plane of the observation optical system S2 is made to coincide with the surface of the wafer 7 only by driving the imaging lens 9. be able to. Using this, the position detection apparatus performs focus adjustment (mark image focus adjustment) of the observation optical system S2 with respect to the wafer mark M1.

  As described above, since the observation optical system S2 is telecentric on both sides, the imaging magnification of the wafer mark M1 by the observation optical system S2 is not changed by the focus adjustment.

  Further, the exit pupil (aperture stop 17) of the projection lens 16 is disposed at a position equivalent to the exit pupil of the objective lens 6 when viewed from the imaging lens 9. Therefore, the relationship between the projection magnification of the index 15 by the projection optical system S3 and the imaging magnification of the wafer mark M1 by the observation optical system S2 is not changed by the focus adjustment.

  Therefore, both the imaging magnification of the wafer mark M1 and the projection magnification of the index 15 are not changed by the focus adjustment, and the positional relationship between the index image and the mark image on the imaging surface is not changed by the focus adjustment.

  2A, 2 </ b> B, and 2 </ b> C are diagrams illustrating the state of the imaging surface during focus adjustment. As shown in FIGS. 2A, 2B, and 2C, since there is a possibility that blurring (eccentricity or tilting) occurs on the optical axis of the optical system during focus adjustment, the mark image IM and the index image IP are respectively There is a possibility of displacement. However, the amount of displacement of the mark image IM and the index image IP due to focus adjustment is common, and the positional relationship between the two does not change.

  Therefore, the position detection device of the present embodiment uses the index image IP instead of the optical axis as a reference for position detection. That is, the position of the wafer mark M1 in the X and Y directions is detected from the position of the mark image IM on the basis of the position of the index image IP on the imaging surface.

  Returning to FIG. 1, the numerical aperture on the image side of the projection optical system S3 is limited to be smaller than the numerical aperture on the image side of the observation optical system S2. For this reason, the aperture diameter of the aperture stop 17 is previously reduced to an appropriate size.

  For example, when the numerical aperture on the image side of the observation optical system S2 is 0.018, the numerical aperture on the image side of the projection optical system S3 is set to 0.004. If the wavelength of infrared light is 1.1 μm and the wavelength of visible light is 0.55 μm, the depth of focus of the observation optical system S2 is 3.4 mm, whereas the depth of focus of the projection optical system S3 is 34 mm. Deepen. Therefore, in the present embodiment, the movable range of the imaging lens 9 described above is set within the focal depth (34 mm) of the projection optical system S3.

  Therefore, as shown in FIGS. 2A, 2B, and 2C, the blur amount of the mark image IM is changed by the focus adjustment, but the index image IP that is a reference for position detection is not blurred. Further, since the numerical aperture on the image side of the observation optical system S2 remains large, the resolution of the mark image IM can be increased as shown in FIG.

  If there is an obstacle between the position detection device and the wafer 7, the mark image IM is affected by noise. Therefore, it is desirable that the resolution is as high as possible, and the index image IP is not affected by noise. The resolution may be slightly lower.

  Further, FIG. 2 is an explanatory diagram to the last, and the actual state of the mark image IM and the index image IP is not always as shown in FIG.

  In the above-described embodiment, the case where the image side numerical aperture of the projection optical system S3 is 0.004 has been described as an example. However, the image side numerical aperture of the projection optical system S3 is set to 0.003 to 0. It may be set to any value in the range of .005, whereby the depth of focus of the projection optical system S3 may be set to any value in the range of 20 mm to about 60 mm.

  If the numerical aperture on the image side of the projection optical system S3 is set to be smaller than 0.003 and the depth of focus of the projection optical system S3 is made deeper than about 60 mm, the resolution of the index image IP is lowered and position detection is performed. The detection accuracy of the device may be lowered. On the other hand, when the numerical aperture on the image side of the projection optical system S3 is set larger than 0.005 and the depth of focus of the projection optical system S3 is shallower than about 20 mm, the position of the mark to be detected in the Z direction It may not be possible to cope with the variation in the focus, and accurate focus adjustment may not be performed.

  Next, the position detection operation by the control unit will be described.

  FIG. 3 is a flowchart of the position detection operation. Prior to the operation, it is assumed that the wafer 7 and the position detecting device are set in an appropriate positional relationship in advance so that the mark image IM is positioned in the imaging surface.

  Step S1: The control unit turns on the illumination light source 1 and turns off the projection light source 11. In this state, as shown in FIG. 4, the camera 10 captures the mark image IM. The control unit continuously drives the camera 10 and the imaging lens 9, refers to the contrast value of the image continuously output from the camera 10, and positions the imaging lens 9 so that the contrast value becomes maximum. And the imaging lens 9 is placed at that position. Thereby, the focus adjustment of the observation optical system S2 is completed.

  Step S2: The control unit drives the camera 10 with the focus adjustment completed, and stores an image output by the camera 10. Hereinafter, this image is referred to as a “first image”.

  Step S3: The control unit turns off the illumination light source 1 and turns on the projection light source 11. In this state, as shown in FIG. 5, the camera 10 captures the index image IP. In this state, the control unit drives the camera 10 and stores an image output from the camera 10. Hereinafter, this image is referred to as a “second image”. Thereafter, the projection light source 11 is turned off.

Step S4: The control unit finds the mark image IM from the first image, and calculates the center coordinate value (X, Y) of the mark image IM in the first image. Further, the control unit finds the index image IP from the second image, and calculates the center coordinate value (X ₀ , Y ₀ ) of the index image IP in the second image. Then, as shown in FIG. 6, the control unit calculates the relative coordinate values (X−X ₀ , Y−Y ₀ ) of the mark image IM with reference to the coordinate values of the index image IP, and the coordinate values (X− X ₀ , Y−Y ₀ ) is output as the detection result of the position in the XY direction of the wafer mark M1.

  As described above, since the position detection apparatus of the present embodiment performs the focus adjustment by moving the imaging lens 9, it is not necessary to move the wafer 7 in the surface normal direction (Z direction).

  When the imaging lens 9 is moved, the optical axis may be blurred. However, the position detection apparatus of the present embodiment projects the index image IP onto the imaging surface via the imaging lens 2 and the index image. Since IP is used as a reference for position detection, blurring of the optical axis does not affect detection accuracy.

  Therefore, the position detection apparatus of the present embodiment has high position detection accuracy despite having a focus adjustment function.

  Further, since the movement accuracy of the imaging lens 9 does not affect the detection accuracy, it is not necessary to make the drive mechanism (including a motor or the like) high-performance, and the cost is low.

  Further, since the imaging lens 9 is lightweight, it is easy to increase the speed of focus adjustment as compared with the case where a wafer stage (not shown) that supports the wafer 7 is driven in the Z direction.

  Further, since the illumination light source 1 of the present embodiment is an infrared light source, even if an obstacle (a member opaque to visible light) is disposed between the position detection device and the wafer 7, the wafer mark M1. Can be detected. For this reason, the position detection apparatus of this embodiment is suitable for a wafer overlay apparatus.

  Note that the contrast method is employed as the focus adjustment method of the present embodiment, but a pupil division method may also be employed.

  Further, although the aperture diameter of the aperture stop 17 of the present embodiment is fixed, it may be variable. If the aperture diameter of the aperture stop 17 is variable, the aperture diameter may be adjusted according to the use of the position detection device.

  For example, when the moving range of the imaging lens 9 needs to be wide (when the variation in the position of the mark to be detected in the Z direction is large), the aperture diameter is set small, and the moving range of the imaging lens 9 is When it may be narrow (when the variation in the position of the mark to be detected in the Z direction is small), the aperture diameter may be set large. By performing such adjustment, it is possible to minimize the amount of decrease in the numerical aperture on the image side of the projection optical system S3, that is, the amount of decrease in the resolution of the index image IP.

  As an example, when the focal length of the imaging lens 9 is 200 mm and the numerical aperture on the image side of the projection optical system S3 is 0.003, the aperture diameter of the aperture stop 17 is set to 1.2 mm. When the focal length of the imaging lens 9 is 200 mm and the numerical aperture on the image side of the projection optical system S3 is 0.004, the aperture diameter of the aperture stop 17 is set to 1.6 mm. When the focal length of the imaging lens 9 is 200 mm and the numerical aperture on the image side of the projection optical system S3 is 0.005, the aperture diameter of the aperture stop 17 is set to 2.0 mm.

In addition, although the control part of the above-mentioned embodiment turned on the light source 1 for illumination and the light source 11 for projection at another timing, it turned on the camera 10 in the state which turned on both the light source 1 for illumination and the light source 11 for projection. The image output by the camera 10 at that time may be stored. In this case, the camera 10 captures the mark image IM and the index image IP. In this case, the control unit finds the mark image IM from this image, calculates the center coordinate value (X, Y) of the mark image IM, finds the index image IP from the same image, and finds the center coordinate value ( X ₀ , Y ₀ ) may be calculated. Then, the control unit calculates a relative coordinate value of the mark image IM relative to the coordinate values of the target image _{IP (X-X 0, Y} -Y 0), coordinate values _{(X-X 0, Y-} Y ₀ ) is output as the detection result of the position of the wafer mark M1 in the XY direction.

[Second Embodiment]
This embodiment is an embodiment of a wafer superimposing apparatus.

  FIG. 7 is a configuration diagram of the wafer superimposing apparatus. As shown in FIG. 7, the wafer superimposing apparatus includes wafer stages WST1 and WST2, position detection devices AS1 and AS2, a control unit (not shown), and the like.

  In the wafer superposing apparatus, the two wafer stages WST1, WST2 are attached in a state of facing each other.

  One wafer W1 to be superimposed is fixed to the wafer holder WH1 by vacuum chucking or electrostatic chucking, and is held on the wafer stage WST1 together with the wafer holder WH1 in this state. Wafer marks (not shown) are formed on the surface of the wafer W1, and reference marks M11 and M12 are formed at locations on the surface of the wafer holder WH1 that are separated from the wafer W1. Here, it is assumed that the positional relationship between the wafer mark (not shown) of the wafer W1 and the reference marks M11 and M12 of the wafer holder WH1 is known by measurements performed in advance.

  The other wafer W2 to be superimposed is fixed to the wafer holder WH2 by vacuum chucking or electrostatic chucking, and is held on the wafer stage WST2 together with the wafer holder WH2 in this state. Wafer marks (not shown) are formed on the surface of the wafer W2, and reference marks M21 and M22 are formed at locations on the surface of the wafer holder WH2 that are separated from the wafer W2. Here, it is assumed that the positional relationship between the wafer mark (not shown) of the wafer W2 and the reference marks M21 and M22 of the wafer holder WH2 is already known by measurement performed in advance.

  When the two wafer stages WST1 and WST2 are driven, the positional relationship between the two wafers W1 and W2 can be changed. Here, for simplicity, it is assumed that only wafer stage WS2 is driven without driving wafer stage WS1. An accurate driving amount of the wafer stage WS2 in the surface direction (XY direction) is detected with high accuracy by a measurement system including the movable mirror MM and the interferometer IF provided on the wafer stage WS2.

  Further, two position detection devices AS1, AS2 are attached to the same side of the wafer superimposing device as wafer stage WST1. Each of the position detection devices AS1 and AS2 is the same as the position detection device of the first embodiment.

  The position detection devices AS1 and AS2 catch the reference marks M11 and M12 formed on the wafer holder WH1 through the wafer holder WH1, and detect the positions of the reference marks M11 and M12 in the XY directions. Thereby, the arrangement state of the wafer W2 in the wafer superimposing apparatus becomes known.

  Further, the position detection devices AS1, AS2 catch the reference marks M21, M22 formed on the wafer holder WH2 through the wafer holder WH1, and detect the positions of the reference marks M21, M22 in the XY directions. Thereby, the arrangement state of the wafer W1 in the wafer superimposing apparatus becomes known.

  Therefore, the control unit (not shown) can align the wafers W1 and W2 by driving the wafer stage WST2 according to the detection results of the position detection devices AS1 and AS2.

  Here, each of the position detection devices AS1 and AS2 has a focus adjustment function as described in the first embodiment. Therefore, as long as the distance between the wafers W1 and W2 is narrowed in advance, a control unit (not shown) moves each of the wafer stages WST1 and WS2 in the surface normal direction (Z direction) when adjusting the focus of the position detection devices AS1 and AS2. There is no need to drive to). Moreover, the position detection devices AS1 and AS2 are highly accurate as described in the first embodiment.

  Therefore, the wafer superimposing apparatus of this embodiment can align the wafers W1 and W2 easily and with high accuracy.

  Further, as described in the first embodiment, since the position detection devices AS1 and AS2 can speed up the focus adjustment, the wafer superimposing process according to the present embodiment increases the efficiency of the wafer superimposing process. You can also Therefore, when the wafer superposition is continuously performed, the throughput of the wafer superposition apparatus is improved.

  In the above description, the position detectors AS1 and AS2 are used to measure the positional relationship between the reference marks of the two wafer holders WH1 and WH2, but the positional relationship between the reference mark and the wafer mark in one wafer holder is determined. It may be used to measure. Incidentally, the measurement is performed with the wafer holder held on the stage WST2 side.

[Third Embodiment]
The present embodiment is an embodiment of a method for manufacturing a stacked three-dimensional semiconductor device.

  Next, a method for manufacturing a stacked three-dimensional semiconductor device will be described.

  FIG. 8 is a flowchart showing a method for manufacturing a stacked three-dimensional semiconductor device. This manufacturing method includes steps S11, S12, S13, S14, and S15. Hereinafter, each process will be described.

  S11: A wafer preparation step of preparing a predetermined number of wafers on which a plurality of semiconductor devices are formed. In this step, as shown in FIG. 9A, the circuit pattern on the mask is reduced and projected onto the wafer coated with the resist using a normal semiconductor exposure apparatus, and the resist is developed, and then etching and thermal diffusion of impurities are performed. Processing is performed to obtain a wafer 511 on which circuit elements 513 are formed.

  S12: This is an alignment process for measuring the positional relationship between wafers to be superimposed on each other. In this step, the positional relationship between the wafers to be superimposed is measured according to the second embodiment described above. Details of this step have already been described with reference to FIG. Note that the alignment may determine the positional relationship between the wafer and the already laminated wafer (wafer laminate). That is, one wafer may be in the form of a wafer stack formed by superimposing a plurality of wafers, possibly thinned by grinding or the like. The same applies to the subsequent steps.

  S13: This is a wafer superimposing step of superimposing wafers whose positional relationship has been measured. In this step, as shown in FIG. 9B, when the wafer is held by the wafer holder and the alignment of the two adjacent wafers is completed, the two wafers are moved to the position shown in FIG. Overlapped as shown. After the contact, in order to maintain the superimposed positional relationship, the holders are temporarily fixed mechanically (for example, a clamp mechanism) or temporarily fixed by an adhesive having a weak bonding force. As shown in FIG. 9 (d), the temporarily fixed holder and wafer stack 321 are transported from the alignment / overlay execution unit 411 to the electrode bonding execution unit 413 by the robot arm 415.

  S14: This is an electrode bonding step for bonding the connection electrodes on the wafers stacked on each other. In this step, the aligned and temporarily fixed wafer stack is mounted with a pressure / heating device as shown in FIG. The parallelism of the upper pressurizer 551, the lower pressurizer 553, and the wafer stack 561 is adjusted, and when this is completed, the wafer stack 561 is pressed by the two pressurizers 551 and 553. At the same time, heating by the heaters 541 and 543 incorporated in the holder is performed according to a predetermined sequence. By applying a predetermined pressure for a predetermined time, the electrodes (metal bump and pad, metal bump and metal bump) on the wafer are bonded. At this time, in some cases, resin is sealed between the wafers and heated. As a result, the stacked wafers are stacked to form a wafer stack.

  The above alignment step (S12), wafer overlay step (S13), and electrode bonding step (S14) are repeated as many times as the number of wafers to be laminated (predetermined number). In some cases, a step of thinning the wafer laminate by grinding, polishing, or etching, a step of encapsulating a sealing resin between the wafers of the wafer laminate, or the like is added after the lamination bonding. As a result, a wafer laminated body in which a predetermined number of wafers are laminated is obtained.

  S15: A dicing process in which individual semiconductor devices are cut out from a wafer stack formed by stacking a predetermined number of wafers. In this step, the wafer laminated and bonded at the wafer level is cut according to a dicing line and cut out as chips. For example, cutting is performed according to the broken line as shown in FIG. For the cutting, a dicing saw method in which cutting is performed using a dicing blade, a method in which a wafer surface is melted and split by a laser beam, and a method in which a cutting line is drawn by a diamond cutter are used. Among them, the dicing saw method is particularly preferable as a method for separating the wafer stack into chips. Each chip cut out in this way is a stacked three-dimensional semiconductor device.

[Fourth Embodiment]
This embodiment is an embodiment of an exposure apparatus.

  FIG. 10 is a block diagram of the exposure apparatus. The exposure apparatus is a step-and-scan projection exposure apparatus, and includes an illumination system 110 that illuminates a mask (reticle R), a reticle stage RST that holds the reticle R, and an image of the reticle R to be exposed (wafer W). A projection optical system PL formed thereon, a wafer stage WST for holding the wafer W, an off-axis alignment detection system (position detection device) AS, a control system (not shown) for controlling each part, and the like are provided.

  Examples of the light source of the illumination system 110 include a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F2 laser (wavelength 157 nm), an EUV light source (wavelength 13.5 nm), or an ultrahigh pressure mercury lamp. used. The illumination light IL emitted from the illumination system 110 illuminates the illumination area on the reticle R with a substantially uniform illuminance.

  The driving amount in the surface direction (XY direction) of reticle stage RST is detected with high accuracy by a measurement system including moving mirror 115 and interferometer 116.

  For the projection optical system PL, for example, a double-sided telecentric refraction type reduction projection optical system is used. The projection optical system PL forms a reduced image of the circuit pattern PA formed on the reticle R on the wafer W.

  On wafer stage WST, wafer W fixed to wafer holder WH is placed. The driving amount in the surface direction (XY direction) of wafer stage WST is detected with high accuracy by a measurement system including moving mirror 117 and interferometer 118.

  A reference mark GM is formed at a position off the wafer W on the surface of the wafer holder WH, and a wafer mark (not shown) is formed on the surface of the wafer W.

  The position detection apparatus AS is the position detection apparatus according to the first embodiment. Prior to the exposure operation by the exposure apparatus, the position of the reference mark GM on the wafer holder WH in the XY direction and the position of the wafer mark on the wafer W in the XY direction. And are detected respectively.

  Therefore, the control unit (not shown) can align the wafer W by driving the wafer stage WST according to the detection result of the position detection device AS.

  Here, the position detection device AS has a focus adjustment function as described in the first embodiment. Therefore, the control unit (not shown) does not need to drive wafer stage WST in the surface normal direction (Z direction) when adjusting the focus of position detection device AS. Moreover, the position detection device AS is highly accurate as described in the first embodiment.

  Therefore, the exposure apparatus of this embodiment can align the wafer W easily and with high accuracy.

  Further, as described in the first embodiment, since the position detection apparatus AS can speed up the focus adjustment, the exposure apparatus of this embodiment can improve the alignment of the wafer W. Therefore, when the exposure of a plurality of wafers is performed continuously, the throughput of the exposure apparatus is improved.

  As shown in FIG. 10, the optical path of the position detection device AS is arranged so as not to interfere with the optical path of the projection optical system PL.

  In the exposure apparatus, since there is no obstacle between the position detection device AS and the reference mark GM (or wafer mark), the illumination light source in the position detection device AS does not need to be an infrared light source, and is visible. It may be a light source. When the illumination light source is a visible light source, it is sufficient that the sensitivity band of the camera in the position detection device AS covers only the visible light region.

[Fifth Embodiment]
The present embodiment is an embodiment of a microdevice manufacturing method.

  FIG. 11 is a flowchart of a microdevice manufacturing method.

  As shown in FIG. 11, a microdevice such as a semiconductor device includes a step 201 for performing a function / performance design of the microdevice, a step 202 for manufacturing a mask (reticle) based on the design step, and a substrate as a substrate of the device. Manufacturing step 203, substrate processing step 204 including substrate processing (exposure processing) for exposing the substrate with an image of the mask pattern according to the above-described fourth embodiment, and developing the exposed substrate, device assembly step (dicing step, (Including processing processes such as a bonding process and a packaging process) 205, an inspection step 206, and the like.

It is a block diagram of a position detection apparatus. It is a figure which shows the mode in the visual field of the observation optical system S at the time of focus adjustment. It is a flowchart of a position detection operation. It is a figure which shows the image acquired in step S1. It is a figure which shows the image acquired in step S3. It is a figure explaining step S4. It is a block diagram of a wafer superposition apparatus. It is a flowchart which shows an example of the manufacturing method of a lamination type three-dimensional semiconductor device. It is a figure explaining an example of the manufacturing method of a lamination type three-dimensional semiconductor device. It is a block diagram of exposure apparatus. It is a flowchart which shows an example of the manufacturing process of a microdevice.

Explanation of symbols

  DESCRIPTION OF SYMBOLS S1 ... Illumination optical system, S2 ... Observation optical system, S3 ... Projection optical system, 10 ... Camera, 1 ... Illumination light source, 5, 8 ... Half mirror, 6 ... Objective lens, 9 ... Imaging lens, 11 ... Projection Light source, 13 ... optical fiber, 15 ... index, 16 ... projection lens, 17 ... aperture stop

Claims (11)

A position detection device that detects the position of an object based on an index,
An imaging lens for forming on an imaging surface an image of the object based on the light beam objective lens is captured,
The light beam from the index to be incident to the object side of the imaging lens, and a projection lens for projecting an image of the index on the imaging surface through the imaging lens,
A focusing mechanism for moving the imaging lens in the optical axis direction ;
The depth of focus of the projection optical system constituted by the projection lens and the imaging lens is
A position detection device characterized by being deeper than a focal depth of an observation optical system constituted by the objective lens and the imaging lens . The position detection device according to claim 1,
The numerical aperture on the image side of the projection optical system constituted by the projection lens and the imaging lens is
A position detection device having a smaller numerical aperture on the image side of an observation optical system constituted by the objective lens and the imaging lens.   In the position detection device according to claim 1 or 2,
  The movable range of the imaging lens is
  Within the depth of focus of the projection optical system
  A position detecting device characterized by that. In the position detection device according to any one of claims 1 to 3,
The exit pupil of the objective lens and the exit pupil of the projection lens viewed from the imaging lens,
A position detection device, wherein the position detection devices are arranged at equivalent positions. In the position detection device according to any one of claims 1 to 4,
A position detection apparatus further comprising a camera that acquires an image of the imaging surface. The position detection device according to claim 5,
A position detection apparatus, further comprising: a control unit that drives the focusing mechanism so that a contrast of an image of the object is increased based on an image acquired by the camera. In the position detection device according to claim 5 or 6,
A position detection apparatus, further comprising: a measuring unit that measures a positional relationship between the image of the object and the image of the index based on an image acquired by the camera. A wafer overlaying device comprising the position detection device according to claim 1. A wafer preparation step of preparing a predetermined number of wafers on which a plurality of semiconductor devices are formed;
An alignment step of measuring a positional relationship between wafers to be superposed on each other among the prepared wafers;
A wafer superimposing step of superimposing the wafers measured in the positional relationship;
An electrode bonding step of bonding the connection electrodes of the stacked wafers and laminating the wafers;
A dicing step of cutting out a plurality of stacked three-dimensional semiconductor devices from the predetermined number of stacked wafers,
The position detecting device according to any one of claims 1 to 7 is used in the alignment step. A method for manufacturing a stacked three-dimensional semiconductor device. An exposure apparatus comprising the position detection device according to any one of claims 1 to 7. Exposing the substrate using the exposure apparatus according to claim 10;
And developing the exposed substrate. A device manufacturing method comprising:

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