Observation device

Abstract

The observation device includes: a condenser lens that focuses transmitted light toward a target object; an imaging unit that receives the transmitted light reflected from the target object and captures an image of the target object; a moving unit that moves the condenser lens relative to the target object; an input unit that receives input from a user; an aberration correction unit that performs aberration correction on the transmitted light; and a control unit that controls at least the aberration correction unit. The aberration correction unit is configured to switch the correction amount of the aberration correction. The control unit can switch the correction amount of at least one of the following based on the input received from the input unit: "Aberration correction performed by the aberration correction unit when the imaging unit captures an image of a first interval on the side of the transmitted light incident surface of the target object" (i.e., aberration correction for the first interval); "Aberration correction performed by the aberration correction unit when the imaging unit captures an image of a second interval inside the target object" (i.e., aberration correction for the second interval); and "Aberration correction performed by the aberration correction unit when the imaging unit captures an image of a third interval on the side opposite to the transmitted light incident surface of the target object" (i.e., aberration correction for the third interval).

Description

Technical Field

[0001] This invention relates to an observation device. Prior Technology

[0002] An observation device is known to observe a target object using transmissive light. For example, Japanese Patent Application Publication No. 2017-64746 describes an observation using an infrared camera in a laser processing apparatus to observe: modified regions formed inside a semiconductor substrate, processing damage formed in a functional element layer, etc. Summary of the Invention

[0003] [The problem the invention aims to solve] In the observation apparatus described above, aberration corrections, such as corrections for spherical aberration of transmitted light, are sometimes performed to achieve accurate observation of the target object. In this case, if the aberration correction amount is fixed, although the production pace (operational efficiency) is high, there is a concern that the aberrations cannot be adequately corrected. On the other hand, it is also considered that the aberration correction amount can be optimized by having the user rotate the correction ring set on the condenser lens each time observation is performed. However, in this case, for example, if the depth position observed in the target object changes, the appropriate correction amount will also change accordingly. Therefore, there is a concern that adjusting the correction amount may reduce the production pace.

[0004] Therefore, the object of the present invention is to provide an observation device that can achieve both "high production speed" and "accurate observation of the target object". [Solutions]

[0005] One aspect of the present invention is an observation device that observes a target object using transmissive light. It comprises: a condenser lens that focuses the transmissive light toward the target object; an imaging unit that receives the transmissive light reflected from the target object and captures an image of the target object; a moving unit that moves the condenser lens relative to the target object; an input unit that receives input from a user; an aberration correction unit that corrects aberrations in the transmissive light; and a control unit that controls at least the aberration correction unit. The aberration correction unit is configured to switch the aberration correction amount, and the control unit can adjust the aberration correction amount according to the target object. The input received by the input unit switches the correction amount of at least one of the following: "Aberration correction performed by the aberration correction unit when the camera unit captures the first interval on the side of the transmitted light incident surface of the target object", i.e., aberration correction for the first interval; "Aberration correction performed by the aberration correction unit when the camera unit captures the second interval inside the target object", i.e., aberration correction for the second interval; and "Aberration correction performed by the aberration correction unit when the camera unit captures the third interval on the side opposite to the transmitted light incident surface of the target object", i.e., aberration correction for the third interval.

[0006] In this observation device, the observation area of ​​the target object is divided into first to third zones (i.e., the side of the target object's transmitted light incident surface, its interior, and the side opposite to the transmitted light incident surface). When observing these first to third zones, aberration corrections can be performed on each zone using correction amounts that switch according to user input. This allows for switching correction amounts to optimize for user input and suppresses the frequency of switching, maintaining a high production rate. In other words, both high production rate and accurate observation of the target object can be achieved.

[0007] In one embodiment of the observation device of the present invention, the aberration correction unit may be configured to switch the aberration correction amount between at least a first correction amount, a second correction amount, and a third correction amount, and the control unit, based on the input received by the input unit, switches the aberration correction amounts for the first interval, the second interval, and the third interval among the first correction amount, the second correction amount, and the third correction amount. In this case, the switching of each correction amount for the first interval, the second interval, and the third interval can be easily realized.

[0008] In one embodiment of the observation device of the present invention, the condenser lens may also include a first condenser lens, a second condenser lens, and a third condenser lens. The aberration correction unit includes: a first aberration correction unit disposed on the first condenser lens for implementing aberration correction of a first amount; a second aberration correction unit disposed on the second condenser lens for implementing aberration correction of a second amount; a third aberration correction unit disposed on the third condenser lens for implementing aberration correction of a third amount; and a rotator mounted with the first condenser lens, the second condenser lens, and the third condenser lens, wherein any one of the first condenser lens, the second condenser lens, and the third condenser lens is arranged on the optical axis of the transmitted light, and the aforementioned rotator is movable to switch any one of the first condenser lens, the second condenser lens, and the third condenser lens arranged on the optical axis of the transmitted light. In this case, by using a rotator to switch the condenser lens on the optical axis of the transmitted light between the first and third condenser lenses, the correction amounts for the first, second, and third intervals of aberration correction can be switched between the first and third correction amounts.

[0009] In one embodiment of the observation device of the present invention, the first correction amount can be smaller than the second correction amount, and the second correction amount can be smaller than the third correction amount. By utilizing the first to third correction amounts with such a size relationship, the correction amount can be optimized.

[0010] In one embodiment of the observation apparatus of the present invention, the first interval uses aberration correction, which can be an aberration correction "for checking whether there are cracks on the transmitted light incident surface exposed in the target object," and the third interval uses aberration correction, which can be an aberration correction "for checking whether there are cracks on the opposite side of the transmitted light incident surface exposed in the target object." In this case, the checks for "whether there are cracks on the transmitted light incident surface exposed in the target object" and "whether there are cracks on the opposite side of the transmitted light incident surface exposed in the target object" can be performed accurately. Furthermore, in one embodiment of the observation apparatus of the present invention, the second interval uses aberration correction, which can also be an aberration correction for checking modified regions formed inside the target object. In this case, modified regions formed inside the target object can be checked accurately.

[0011] In one aspect of the observation device of the present invention, the control unit can also acquire information related to the position of the detection target based on the amount of movement of the condenser lens implemented by the moving unit and the correction coefficient, and switch the correction coefficient according to the switching of the correction amount of the first interval aberration correction, the second interval aberration correction, and the third interval aberration correction. In this case, the depth position of the detection target (e.g., the modified region) in the target object can be acquired with high precision.

[0012] In one embodiment of the observation device of the present invention, the input unit may also receive input related to "the content of the inspection of the target object," and the control unit switches the correction amounts of the aberration correction for the first interval, the aberration correction for the second interval, and the aberration correction for the third interval based on the input received by the input unit that is "related to the content of the inspection." In this case, the correction amounts of the aberration correction for the first interval, the aberration correction for the second interval, and the aberration correction for the third interval can be optimized based on the user's input that is "related to the content of the inspection."

[0013] In one embodiment of the observation device of the present invention, the input unit can also receive input related to "the type of processing conditions for laser processing of the target object," and the control unit switches the correction amounts for aberration correction in the first interval, the second interval, and the third interval based on the input related to "the type of processing conditions" received by the input unit. In this case, the correction amounts for aberration correction in the first interval, the second interval, and the third interval can be optimized based on the user's input related to "the type of processing conditions."

[0014] In one aspect of the observation device of the present invention, the input unit can also receive an input "related to the thickness of the target object," and the control unit switches the correction amounts of the aberration correction for the first interval, the aberration correction for the second interval, and the aberration correction for the third interval based on the "related to the thickness of the target object" input received by the input unit. In this case, the correction amounts of the aberration correction for the first interval, the aberration correction for the second interval, and the aberration correction for the third interval can be optimized based on the "related to the thickness of the target object" input from the user.

[0015] In one embodiment of the observation device of the present invention, the input unit can also receive input indicating whether the input mode is a simple input mode or a detailed input mode. When the input mode is determined to be "related to the detailed input mode," the unit receives inputs of correction amounts for aberration correction in the first, second, and third intervals. In this case, the user can input the correction amounts for aberration correction in the first, second, and third intervals by using the detailed input mode as the input mode.

[0016] In one embodiment of the observation device of the present invention, the second interval side of the first interval and the first interval side of the second interval may repeat in the first repeating interval, and the third interval side of the second interval and the second interval side of the third interval may repeat in the second repeating interval. The control unit performs the following: performing aberration correction for the first interval by the aberration correction unit while capturing an image of the first repeating interval by the imaging unit; performing aberration correction for the second interval by the aberration correction unit while capturing an image of the first repeating interval by the imaging unit; performing aberration correction for the second interval by the aberration correction unit while capturing an image of the second repeating interval by the imaging unit; and performing aberration correction for the third interval by the aberration correction unit while capturing an image of the second repeating interval by the imaging unit. In this case, more accurate observation can be performed in the first and second repeating intervals of the target object. In addition, sometimes, based on input content such as the thickness of the target object, accurate observation can be performed only by performing aberration correction for the first and third intervals.

[0017] According to one embodiment of the present invention, an observation device is provided that enables both "high production speed" and "accurate observation of the target object". Simple Explanation of the Diagram

[0018] [Figure 1] is a structural diagram of the laser processing apparatus according to the embodiment.

[0019] [Figure 2] is a top view of the target object in Figure 1.

[0020] [Figure 3] is a cross-sectional view showing a portion of the target object in Figure 2.

[0021] [Figure 4] is a structural diagram of the laser processing head shown in Figure 1.

[0022] [Figure 5] is a structural diagram showing the observation unit in Figure 1.

[0023] [Figure 6] is a perspective view of the transmitted light focusing lens and rotator of the observation unit in Figure 1.

[0024] [Figure 7] is a flowchart illustrating an example of the operation in the laser processing apparatus of Figure 1.

[0025] [Figure 8] is a cross-sectional view of the target object used to illustrate direct observation and back-reflection observation.

[0026] [Figure 9(a)] is an example of a data table showing the amount of correction for aberration correction in the first interval, the second interval, and the third interval. [Figure 9(b)] is another example of a data table showing the amount of correction for aberration correction in the first interval, the second interval, and the third interval.

[0027] [Figure 10] is a diagram showing an example of the input screen of the GUI when observing an object for inspection.

[0028] [Figure 11] is another example of the input screen of the GUI when observing for inspection of a target object.

[0029] [Figure 12] is a diagram showing an example of the input screen of the GUI when observing a target object for setting processing conditions.

[0030] [Figure 13] is another example of the GUI input screen when observing a target object for setting processing conditions.

[0031] [Figure 14] is a flowchart showing the process of observing a target object in the observation device of Figure 1.

[0032] [Figure 15] is a schematic cross-sectional view of the target object used to illustrate the processing in Figure 14.

[0033] [Figure 16] is a flowchart showing the process of observing and determining the processing conditions in the observation device of Figure 1.

[0034] [Figure 17] is a flowchart showing the subsequent events of Figure 16.

[0035] [Figure 18] is a flowchart showing the subsequent events of Figure 17.

[0036] [Fig. 19(a)] is a schematic cross-sectional view of the target object used to illustrate the processing of Fig. 16. [Fig. 19(b)] is a subsequent schematic cross-sectional view showing Fig. 19(a).

[0037] [Figure 20] is a schematic cross-sectional view showing the subsequent figure of Figure 19(b).

[0038] [Figure 21] is a table showing the relationship between the correction amount of aberration correction and the judgment of various inspection contents.

[0039] [Figure 22] is a perspective view of the observation unit of the first modified example.

[0040] [Figure 23] is a perspective view of the observation unit of the second modified example.

[0041] [Figure 24] is a schematic diagram showing the structure of the observation unit in the third modified example.

[0042] [Figure 25] is a schematic diagram showing the structure of the observation unit in the fourth modified example.

[0043] [Figure 26] is a schematic diagram showing the structure of a modified laser processing apparatus. Implementation

[0044] The embodiments will now be described in detail with reference to the accompanying drawings. In the descriptions of the drawings, identical or equivalent parts are labeled with the same symbols, and repeated descriptions are sometimes omitted. In the drawings, a rectangular coordinate system defined by the X-axis, Y-axis, and Z-axis is sometimes shown. As an example, the X-direction and Y-direction are mutually intersecting (orthogonal) first and second horizontal directions, respectively, and the Z-direction is a perpendicular direction intersecting (orthogonal) the X-direction and Y-direction.

[0045] As shown in Figure 1, the laser processing apparatus 1 of the embodiment includes a stage 2; a laser processing head 3; alignment cameras 5 and 6; an observation unit 4; a first vertical movement mechanism 7A; a second vertical movement mechanism 7B; a first horizontal movement mechanism 8A; a second horizontal movement mechanism 8B; a control unit 9; and a GUI (Graphical User Interface) 10. The laser processing apparatus 1 is a device that forms a modified region 12 (see Figure 4) on a target object 20 by irradiating the target object 20 with laser light L.

[0046] As shown in Figures 2 and 3, the target object 20 is, for example, a wafer. The target object 20 includes a semiconductor substrate 21 and a functional element layer 22. The semiconductor substrate 21 has a surface 21a and a back surface 21b. The semiconductor substrate 21 is, for example, a silicon substrate. The functional element layer 22 is formed on the surface 21a of the semiconductor substrate 21. The functional element layer 22 includes a plurality of functional elements 22a arranged in two dimensions along the surface 21a. The functional elements 22a are, for example, light-receiving elements such as photodiodes, light-emitting elements such as laser diodes, and circuit elements such as memory. Sometimes, the functional elements 22a are stacked in multiple layers to form a three-dimensional structure. Furthermore, the target object 20 may or may not have a functional element layer 22, or it may be a bare wafer. A notch 21c indicating a crystal orientation is provided on the semiconductor substrate 21, but an orientation plane may be provided instead of the notch 21c.

[0047] The target object 20 is cut into each functional element 22a along a plurality of lines 15. When viewed from the thickness direction of the target object 20, the plurality of lines 15 pass between each of the plurality of functional elements 22a. More specifically, when viewed from the thickness direction of the target object 20, the lines 15 pass through the center (center in the width direction) of the channel region 23. The channel region 23 extends in the functional element layer 22 in a manner that passes between adjacent functional elements 22a. In this embodiment, the plurality of functional elements 22a are arranged in a matrix along the surface 21a, and the plurality of lines 15 are set in a grid pattern. Furthermore, the lines 15 are imaginary lines, but they can also be actually drawn lines.

[0048] As shown in Figure 1, a target object 20 is placed on a stage 2. The stage 2 supports the target object 20, for example, by adsorbing it. The stage 2 can move along the X direction by a first horizontal moving mechanism 8A. The stage 2 can move along the Y direction by a second horizontal moving mechanism 8B. The stage 2 is configured to rotate about a rotation axis along the Z direction. The stage 2 has a known rotation drive device (not shown) such as a motor, which drives the rotation about the rotation axis. The rotation of the stage 2 is controlled by a control unit 9.

[0049] As shown in Figures 1 and 4, the laser processing head 3 is an irradiation section that irradiates a target object 20 supported by the stage 2 with a transmissive laser light L. The laser processing head 3 focuses the laser light L into the interior of the target object 20. If the laser light L is focused into the interior of the target object 20 supported by the stage 2, the laser light L is specifically absorbed at the portion corresponding to the focusing position of the laser light L (at least a portion of the focusing area), forming a modified region 12 inside the target object 20.

[0050] The modified region 12 is a region whose density, refractive index, mechanical strength, and other physical properties differ from the surrounding unmodified region. Examples of modified regions 12 include melt-treated regions, cracked regions, insulation breakdown regions, and regions with refractive index changes. The modified region 12 has the characteristic that cracks easily extend from the modified region 12 towards the incident side of the laser light L and the opposite side. This characteristic of the modified region 12 is used for cutting the target object 20.

[0051] The laser processing head 3 has a laser beam focusing lens 33 and an observation camera 35 within a frame H3. Laser light L is incident from an external light source 31 into the frame H3 of the laser processing head 3. The light source 31 outputs laser light L, for example, via pulse oscillation. The laser beam focusing lens 33 focuses the laser light L onto the target object 20 supported by the stage 2. In the laser processing head 3, the laser light L incident from the light source 31 is incident on the laser beam focusing lens 33 within the frame H3 via a beam splitter 32, and is focused onto the target object 20 by the laser beam focusing lens 33. The laser beam focusing lens 33 may also be a lens unit comprising a plurality of objective lenses. The frame H3 includes a mounting portion 39 disposed on its side, through which it is connected to and supported by the first vertical movement mechanism 7A described below.

[0052] The observation camera 35 captures an image of the target object 20 supported by the stage 2 using visible light V. The observation camera 35 captures the image of the target object 20 formed by the visible light V emitted from the visible light source 36. Specifically, the visible light V emitted from the visible light source 36 is reflected by the beam splitter 37, passes through the beam splitter 32, and then illuminates the target object 20 via the laser beam focusing lens 33. This visible light V is reflected from the laser incident surface of the target object 20, passes through the laser beam focusing lens 33 and the beam splitters 32 and 37, and is received by the observation camera 35 via the lens 38. Markers (not shown) that assign scale lines to the visible light V can also be provided in the optical path of the visible light V. The observation camera 35 is connected to the control unit 9. The observation camera 35 outputs the captured visible image to the control unit 9. There are no particular limitations on the observation camera 35; any known camera can be used as long as it meets the required performance.

[0053] The alignment cameras 5 and 6 acquire alignment information (hereinafter referred to as "alignment") for the focusing position of the laser light L in the target object 20. The alignment cameras 5 and 6 acquire images as alignment information by illuminating the target object 20 with light and detecting the light reflected back from the target object 20. The alignment cameras 5 and 6 photograph the target object 20 supported by the stage 2.

[0054] The alignment camera 5 has a light source that outputs light that is transparent to the target object 20. The light source is, for example, composed of a halogen lamp and a filter, and outputs light in the near-infrared region. The alignment camera 5 has a light detection unit that detects light reflected from the surface 21a of the target object 20. The light detection unit is, for example, composed of a Si camera or an InGaAs camera, and detects light in the near-infrared region.

[0055] For example, the alignment camera 5 illuminates the target object 20 from the back side 21b, which serves as the laser incident surface, and detects the light returning from the surface 21a (functional element layer 22), thereby capturing an image of the functional element layer 22. Similarly, the alignment camera 5 illuminates the target object 20 from the back side 21b and detects the light returning from the formation location of the modified region 12 in the semiconductor substrate 21, thereby acquiring an image of the area containing the modified region 12. These images are used for alignment. The alignment camera 6 has the same structure as the alignment camera 5, except that its lens is a point lens with lower magnification. The alignment camera 6 is used for alignment in the same way as the alignment camera 5.

[0056] Alignment cameras 5 and 6 are mounted on the laser processing head 3 and move integrally with it. In the illustrated example, alignment cameras 5 and 6 are fixed to the mounting portion 39 of the laser processing head 3. Alignment cameras 5 and 6 are connected to the control unit 9. Alignment cameras 5 and 6 output the captured images to the control unit 9. There are no particular limitations on the alignment cameras 5 and 6; various known cameras can be used as long as they meet the required performance.

[0057] As shown in Figures 1 and 5, the observation unit 4 uses transmissive light to observe the target object 20. The observation unit 4 illuminates the target object 20 with transmissive light and detects the transmissive light returning from the target object 20, thereby observing the interior of the target object 20. For example, the observation unit 4 captures images of the modified region 12 formed in the target object 20 and the leading edge of the crack 14 extending from the modified region 12.

[0058] As shown in Figure 5, the observation unit 4 includes a light source 41, a mirror 42, a light-concentrating lens 43, and a light detection unit 44 within a frame H4. The frame H4 includes a mounting portion 49 disposed on its side, via which it is connected to and supported by the second vertical movement mechanism 7B described below. The observation unit 4 is connected to the control unit 9. The observation unit 4 outputs an image (internal image) captured by the light detection unit 44 to the control unit 9.

[0059] Light source 41 outputs transmissive light I1. Light source 41 is, for example, composed of a halogen lamp and a filter, and outputs transmissive light I1 in the near-infrared region. The transmissive light I1 output from light source 41 is reflected by mirror 42 and passes through transmissive light focusing lens 43, illuminating the target object 20 from the back side 21b of semiconductor substrate 21.

[0060] The transmitted light condensing lens 43 is a lens that focuses the transmitted light I1 toward the semiconductor substrate 21 of the target object 20. The transmitted light condensing lens 43 allows the transmitted light I1 reflected from the surface 21a of the semiconductor substrate 21 to pass through. The transmitted light condensing lens 43 has a first condensing lens 43A, a second condensing lens 43B, and a third condensing lens 43C (see Figure 6). The specifications of the first condensing lens 43A, the second condensing lens 43B, and the third condensing lens 43C can be the same or different. The first condensing lens 43A, the second condensing lens 43B, and the third condensing lens 43C are cylindrical with their optical axes as the axial direction.

[0061] The light detection unit 44 detects the transmitted light I1 that has passed through the transmitted light focusing lens 43 and the mirror 42. The light detection unit 44 is, for example, an InGaAs camera. The light detection unit 44 receives the transmitted light I1 in the near-infrared region reflected by the target object 20 and captures an image of the target object 20. The light detection unit 44 constitutes an imaging unit.

[0062] The observation unit 4 includes an aberration correction unit 46 that performs aberration correction (hereinafter also simply referred to as "aberration correction") on the transmitted light I1. The aberration correction unit 46 is configured to switch the correction amount of the aberration correction. The aberration correction unit 46 corrects spherical aberration generated in the transmitted light I1. Spherical aberration refers to the aberration in which light rays from a point source do not converge to a focal point in an optical system containing a sphere. For example, if light is incident on a lens, sometimes "light passing near the optical axis of the lens" and "light passing away from the optical axis" will not converge to a point and will spread out; this is spherical aberration. The aberration correction unit 46 includes a first aberration correction unit 47A, a second aberration correction unit 47B, a third aberration correction unit 47C, and a rotator 48.

[0063] A first aberration correction unit 47A is provided on a first condenser lens 43A to achieve aberration correction of a first correction amount. The first aberration correction unit 47A has a correction ring 47x. That is, the first condenser lens 43A constitutes a so-called correction ring lens. In the first aberration correction unit 47A, by rotating the correction ring 47x, a portion of the lens group constituting the first condenser lens 43A is moved along the optical axis, thereby adjusting the first correction amount. A second aberration correction unit 47B is provided on a second condenser lens 43B to achieve aberration correction of a second correction amount. The second aberration correction unit 47B has a correction ring 47y. That is, the second condenser lens 43B constitutes a so-called correction ring lens. In the second aberration correction unit 47B, by rotating the correction ring 47y, a portion of the lens group constituting the second condenser lens 43B is moved along the optical axis, thereby adjusting the second correction amount.

[0064] The third aberration correction unit 47C is provided on the third condenser lens 43C to achieve aberration correction of the third correction amount. The third aberration correction unit 47C has a correction ring 47z. That is, the third condenser lens 43C constitutes a so-called correction ring lens. The third aberration correction unit 47C adjusts the third correction amount by rotating the correction ring 47z to move a part of the lens group constituting the third condenser lens 43C along the optical axis. The rotation of the correction rings 47x, 47y, and 47z can be achieved manually by the user or by a drive unit (not shown) under the control of the control unit 9. There are no particular limitations on the first aberration correction unit 47A, the second aberration correction unit 47B, and the third aberration correction unit 47C; for example, an aspherical lens can also be used.

[0065] The rotator 48 includes a fixed part 48a and a rotating part 48b. The fixed part 48a is fixed to the frame H4. The rotating part 48b is a circular plate with its thickness along the Z direction and is configured to rotate relative to the fixed part 48a with a rotation axis passing through its center as its base axis. A first condenser lens 43A, a second condenser lens 43B, and a third condenser lens 43C are installed at three circumferentially spaced positions in the rotating part 48b. The first condenser lens 43A, the second condenser lens 43B, and the third condenser lens 43C have their optical axes arranged along the Z direction.

[0066] The rotator 48 positions any one of the first condenser lens 43A, the second condenser lens 43B, and the third condenser lens 43C on the optical axis of the transmitted light I1. The rotator 48 is movable (rotating relative to the fixed part 48a about the rotation axis) to switch any one of the first condenser lens 43A, the second condenser lens 43B, and the third condenser lens 43C positioned on the optical axis of the transmitted light I1. With this structure, the aberration correction unit 46 is configured to switch the aberration correction amount between at least a first correction amount, a second correction amount, and a third correction amount by rotating the rotating part 48b of the rotator 48.

[0067] As shown in Figure 1, the first vertical movement mechanism 7A is a movement mechanism that moves the laser processing head 3 along the Z-direction together with the alignment cameras 5 and 6. The first vertical movement mechanism 7A has a first vertical axis 71 provided on a columnar first base portion 75. The first base portion 75 is fixed to, for example, a mounting surface. The first vertical axis 71 extends along the Z-direction. The mounting portion 39 of the laser processing head 3 is movably mounted on the first vertical axis 71 along the Z-direction. This first vertical movement mechanism 7A, driven by a drive source (not shown), moves the laser processing head 3 along the first vertical axis 71 in the Z-direction. There are no particular limitations on the first vertical movement mechanism 7A; various mechanisms can be used as long as they enable the laser processing head 3 to move along the Z-direction.

[0068] The second vertical movement mechanism 7B is a movement mechanism that moves the observation unit 4 along the Z direction. The second vertical movement mechanism 7B has a second vertical axis 72 provided on a columnar second base portion 76 fixed to, for example, a mounting surface. The second base portion 76 is separated from the first base portion 75 along the X direction. For example, the separation distance between the second base portion 76 and the first base portion 75 is greater than or equal to the width of the laser processing head 3 in the X direction.

[0069] The second vertical axis 72 extends along the Z direction. The mounting portion 49 of the observation unit 4 is movably mounted on the second vertical axis 72 along the Z direction. This second vertical movement mechanism 7B moves the observation unit 4 along the second vertical axis 72 in the Z direction by the driving force of a drive source (not shown). There are no particular limitations on the second vertical movement mechanism 7B; various mechanisms can be used as long as they can move the observation unit 4 along the Z direction. The second vertical movement mechanism 7B constitutes a moving part that moves the transmitted light focusing lens 43 relative to the target object 20.

[0070] The first horizontal moving mechanism 8A is a moving mechanism that moves the stage 2 along the X direction. The first horizontal moving mechanism 8A has a first horizontal axis 81 fixed to, for example, a mounting surface. The first horizontal axis 81 extends along the X direction. The stage 2 is movably mounted to the first horizontal axis 81 along the X direction via a second horizontal moving mechanism 8B. This first horizontal moving mechanism 8A, driven by a drive source (not shown), moves the stage 2 and the second horizontal moving mechanism 8B along the first horizontal axis 81 in the X direction. There are no particular limitations on the first horizontal moving mechanism 8A; various mechanisms can be used as long as they enable the stage 2 to move along the X direction.

[0071] The second horizontal moving mechanism 8B is a moving mechanism that moves the stage 2 along the Y direction. The second horizontal moving mechanism 8B, for example, has a second horizontal shaft 82 provided on the first horizontal moving mechanism 8A. The second horizontal shaft 82 extends along the Y direction. The stage 2 is movably mounted on the second horizontal shaft 82 along the Y direction. The second horizontal shaft 82 can move together with the stage 2 along the first horizontal shaft 81. This second horizontal moving mechanism 8B moves the stage 2 along the second horizontal shaft 82 in the Y direction by the driving force of a drive source (not shown). There are no particular limitations on the second horizontal moving mechanism 8B; various mechanisms can be used as long as they enable the stage 2 to move along the Y direction.

[0072] The control unit 9 is configured as a computer device including a processor, memory, storage, and communication devices. In the control unit 9, the processor executes software (programs) loaded into the memory, etc., controlling the reading and writing of data in the memory and storage, and the communication devices. The control unit 9 controls various operations of the laser processing apparatus 1. The control unit 9 controls the operation of the rotary drive device of the stage 2, the laser processing head 3, the alignment cameras 5 and 6, the observation unit 4, the first vertical movement mechanism 7A, the second vertical movement mechanism 7B, the first horizontal movement mechanism 8A, the second horizontal movement mechanism 8B, and the GUI 10.

[0073] GUI10 displays various information. GUI10 displays the imaging results from observation unit 4 and the imaging results from aiming cameras 5 and 6. GUI10 may include, for example, a touch screen display. Various settings related to processing conditions are input into GUI10 through user touch operations. GUI10 constitutes an input unit that receives input from the user.

[0074] In the laser processing apparatus 1, as an example, laser light L is irradiated from the back side 21b of the semiconductor substrate 21 toward the target object 20, and the stage 2 is moved along line 15, causing the focusing position (focus point) of the laser light L to move relative to the target object 20 along line 15, thereby forming a plurality of modified points arranged along line 15. A modified point is formed by irradiation with a pulse of laser light L. A row of modified regions 12 is a collection of a plurality of modified points arranged in a row. Adjacent modified points are sometimes connected to each other and sometimes separated, depending on the relative movement speed of the focusing position relative to the target object 20 and the repetition frequency of the laser light L. In this embodiment, as shown in FIG4, two rows of modified regions 12 are formed along line 15 inside the semiconductor substrate 21. The two rows of modified regions 12 are adjacent in the thickness direction (Z direction) of the target object 20. The two rows of modified regions 12 are formed by moving two focusing positions C relative to the semiconductor substrate 21 along line 15.

[0075] In the laser processing apparatus 1, as described above, the frame H3 of the laser processing head 3 is supported by the first vertical movement mechanism 7A so that it can move along the Z direction. Accordingly, the laser processing head 3 and the alignment cameras 5 and 6 provided on the laser processing head 3 are configured to move along the Z direction but cannot move along the X and Y directions. In the laser processing apparatus 1, as described above, the frame H4 of the observation unit 4 is supported by the second vertical movement mechanism 7B so that it can move along the Z direction. Accordingly, the observation unit 4 is configured to move along the Z direction but cannot move along the X and Y directions. In the above, the stage 2, the observation unit 4, the second vertical movement mechanism 7B, the control unit 9, the GUI 10, the first horizontal movement mechanism 8A, and the second horizontal movement mechanism 8B constitute the observation apparatus 100.

[0076] Next, a summary of the operation of the laser processing apparatus 1 will be illustrated with reference to the flowchart in FIG7. First, after startup, and after preheating and calibration of each device, the target object 20 is placed on the stage 2 by a robotic arm (not shown), and the target object 20 is adsorbed onto the stage 2 (step S101). Next, alignment is performed (step S102). In step S102, the control unit 9 controls the operation of the first horizontal movement mechanism 8A and the second horizontal movement mechanism 8B based on the image acquired by the alignment camera 5 or the alignment camera 6 (e.g., an image of the functional element layer 22 of the target object 20), so that the stage 2 moves along the X and Y directions, and the focusing position of the laser light L is aligned with the alignment position. For example, viewed from the Z direction, the alignment position is the processing start position (predetermined position) on line 15. In addition, in step S102, the position information of the stage 2 at the time of alignment is acquired as alignment information.

[0077] Next, height setting is performed (step S103). In step S103, the control unit 9 controls the operation of the first vertical movement mechanism 7A based on the visible image acquired by the observation camera 35 (e.g., the image of the laser incident surface of the target object 20), causing the laser processing head 3 (i.e., the laser light focusing lens 33) to move along the Z direction, so that the focusing position of the laser light L is located on the laser incident surface. Next, the control unit 9 controls the operation of the first vertical movement mechanism 7A, causing the laser processing head 3 to move along the Z direction, so that the focusing position of the laser light L is located at a predetermined depth from the laser incident surface, based on the position at the height setting. Next, the control unit 9 appropriately controls the ON / OFF of the laser light L from the laser processing head 3, and the operation of the first horizontal movement mechanism 8A, the second horizontal movement mechanism 8B, and the rotation drive device of the stage 2, causing the stage 2 to move, so that the focusing position of the laser light L moves relative to each other along the plurality of lines 15. Accordingly, a modified region 12 is formed inside the target object 20 along multiple lines 15 (step S104).

[0078] Next, internal observation of the target object 20 is performed. During internal observation of the target object 20, the control unit 9 controls the rotation drive device, the first horizontal movement mechanism 8A, and the second horizontal movement mechanism 8B of the stage 2 to move the stage 2 so that the target object 20 is positioned at the starting position of internal observation performed by the observation unit 4 (step S105). In step S105, based on the alignment information obtained in step S102 above, the positions of the target object 20 in the X, Y, and θ directions are controlled so that the optical axis of the transmitted light focusing lens 43 is aligned with the alignment position of the target object 20 (here, the processing start position on line 15).

[0079] Next, the observation unit 4 performs internal observation of the target object 20, acquiring a plurality of internal images (step S106). In step S106, for example, at at least one location on each line 15, the observation unit 4 performs the subsequent internal observation process under the control of the control unit 9. That is, the observation unit 4 is moved along the Z direction by the second vertical movement mechanism 7B, so that the focusing position of the transmitted light I1 is aligned with a plurality of locations inside the target object 20 to capture images of the target object 20, acquiring a plurality of internal images. Information related to the amount of movement of the observation unit 4 is associated with each of the plurality of internal images, and this information is acquired as imaging data. The acquisition of such imaging data is repeated by aligning the optical axis of the transmitted light focusing lens 43 with the same line 15 or other locations on other lines 15.

[0080] Next, the control unit 9 determines the processing state based on the acquired camera data (step S107). In step S107, as an example, image recognition is used to automatically determine which of the internal images in the plurality of camera data has a relatively clear image of the crack 14 (AI determination). The control unit 9 calculates the crack position based on the amount of movement when capturing the determined internal image. The crack position can be calculated, for example, by multiplying a predetermined correction factor by the amount of movement. The correction factor will be described later. In addition, the control unit 9 estimates the position of the modified region 12 based on the acquired crack position, etc. Next, the control unit 9 saves the determination result determined in step S107 to any storage device. The control unit 9 displays the determination result determined in step S107 on the GUI 10 (step S8). The processing ends with the above steps.

[0081] In the observation unit 4 of this embodiment, for example, "direct observation" and "back reflection observation" can be used to detect the crack 14 and the modified region 12, and obtain information related to their positions. As shown in FIG8, direct observation is when the transmitted light I1 is incident from the back surface 21b and the focal point of the transmitted light I1 is directly aligned with the crack 14 without reflection from the surface 21a (when the focal point F is aligned with the crack 14 from the back surface 21b side). Back reflection observation is when the transmitted light I1 is incident from the back surface 21b and the focal point of the transmitted light I1 reflected from the surface 21a is aligned with the crack 14 (when the focal point is aligned from the back surface 21b side with the region opposite to the surface 21a and the back surface 21b, and an imaginary focal point symmetrical about the surface 21a and the focal point is aligned with the crack 14).

[0082] In the processing state determination (AI determination) of this embodiment, for example, straight line groups are first detected in the internal image of the target object 20. Hough transform or LSD (Line Segment Detector) algorithms are used in the detection of straight line groups. Hough transform is a method that detects all straight lines passing through a point in the image, weighting lines passing through more feature points while detecting straight lines. LSD is a method that estimates regions that are line segments by calculating the gradient and angle of brightness values ​​within the image, and detects straight lines by approximating these regions as rectangles. For straight line groups, cracks 14 are detected from the straight line groups by calculating their similarity to crack lines.

[0083] Furthermore, in the processing state determination (AI determination) of this embodiment, for example, corners (concentration of edges) within the internal image detection image of the target object 20 are identified as key points, and their position, size, and orientation are detected to detect feature points. Eigen, Harris, Fast, SIFT, SURF, STAR, MSER, ORB, AKAZE, etc., are known methods for detecting feature points in the above manner. Because the modified regions (dents) 12 are arranged in circular or rectangular shapes at regular intervals, they exhibit strong corner features. Therefore, by statistically analyzing the feature quantities of feature points within the image, the modified regions 12 can be detected with high precision. Once the total number of feature quantities in each image captured after displacement in the depth direction is compared, the change in the peak value representing the crack 14 can be confirmed. The peak value of this change is estimated as the position of the modified regions 12.

[0084] Next, the processing of the control unit 9 and the input of the GUI 10 in this embodiment will be explained in detail.

[0085] Control unit 9 controls aberration correction unit 46. Based on the input received from GUI 10, control unit 9 switches the correction amount of at least one of the following: aberration correction performed by aberration correction unit 46 when imaging the first interval of the target object 20 on the side of the transmitted light incident surface by light detection unit 44 (i.e., aberration correction for the first interval); aberration correction performed by aberration correction unit 46 when imaging the second interval inside the target object 20 by light detection unit 44 (i.e., aberration correction for the second interval); and aberration correction performed by aberration correction unit 46 when imaging the third interval of the target object 20 on the side opposite to the transmitted light incident surface by light detection unit 44 (i.e., aberration correction for the third interval).

[0086] The first interval of aberration correction can also be used to check the presence or absence of cracks 14 on the back surface 21b, which is the surface through which transmitted light I1 is incident, exposed in the target object 20. The first interval of aberration correction can also be used to check the aberration of the modified region 12 (dent) on the back surface 21b side of the target object 20. The second interval of aberration correction can also be used to check the aberration of the modified region 12 formed inside the target object 20 (the portion outside the surface 21a side and the back surface 21b side). The second interval of aberration correction can also be used to check the presence or absence of areas inside the target object 20 that may appear uneven (so-called end-face unevenness) and black stripe-like areas (so-called black stripes) on the cut surface after cutting. The third interval of aberration correction can also be used to check the presence or absence of cracks 14 on the opposite side of the transmitted light incident surface, i.e., the surface 21a, exposed in the target object 20. The third interval can also be used to check the aberration correction of the modified region 12 on the surface 21a side of the target object 20.

[0087] For the range of the first to third intervals, the thickness settings for each target object 20 can be stored in the control unit 9, or they can be input or selected through the GUI 10 as described later. For example, the control unit 9 can also pre-store a "data table that distinguishes the aberration correction amounts for the first to third intervals according to the input content category of the GUI 10", and switch the aberration correction amounts for the first to third intervals based on the data table and the actual input received by the GUI 10.

[0088] Based on the input received from the GUI10, the control unit 9 switches the correction amounts for aberration correction in the first, second, and third intervals among the first, second, and third correction amounts. Specifically, when switching the correction amount to the first correction amount, the control unit 9 rotates the rotator 48, causing the first condenser lens 43A, which is equipped with the first aberration correction unit 47A, to be positioned on the optical axis of the transmitted light I1. When switching the correction amount to the second correction amount, the control unit 9 rotates the rotator 48, causing the second condenser lens 43B, which is equipped with the second aberration correction unit 47B, to be positioned on the optical axis of the transmitted light I1. When switching the correction amount to the third correction amount, the control unit 9 rotates the rotator 48, causing the third condenser lens 43C, which is equipped with the third aberration correction unit 47C, to be positioned on the optical axis of the transmitted light I1.

[0089] The control unit 9 acquires information related to the depth position (position in the Z direction) of the observation unit 4 (transmitted light focusing lens 43) implemented by the second vertical movement mechanism 7B, based on the amount of movement and correction coefficient along the Z direction. The control unit 9 switches the correction coefficient according to the amount of correction applied to the first interval, the second interval, and the third interval. The correction coefficient is explained in detail below.

[0090] The correction factor is a predetermined coefficient multiplied by the amount of movement in the Z direction of the transmitted light focusing lens 43. To adjust the position of the focusing point of the transmitted light I1 inside the semiconductor substrate 21, the observation unit 4 is moved along the Z direction by a movement amount Fz. In this case, if there were no semiconductor substrate 21, the movement amount of the focusing point of the transmitted light I1 would also be the movement amount Fz. However, when the focusing point of the transmitted light I1 is formed inside the semiconductor substrate 21, the movement amount of the focusing point of the transmitted light I1 becomes an actual movement amount Hz, which is different from the movement amount Fz. The actual movement amount Hz defines the actual imaging position within the semiconductor substrate 21, that is, the position of the detection target. On the other hand, the information that the control unit 9 can directly obtain is the movement amount Fz of the observation unit 4 (that is, the movement amount Fz of the focusing point when there is no semiconductor substrate 21). Therefore, in order to obtain the actual position of the detection target within the semiconductor substrate 21, the control unit 9 needs to multiply the movement amount Fz by any coefficient. The coefficient applied at this time is the correction factor.

[0091] The GUI10 receives input related to the content of the inspection performed on the target object 20. The control unit 9 switches the correction amounts for aberration correction in the first interval, the second interval, and the third interval based on the input received by the GUI10 related to the inspection content. Examples of the inspection content include: FC inspection, used to check for "cracks 14 and modified regions 12 formed from surface 21a to back surface 21b in the target object 20"; BHC inspection, used to check for cracks 14 exposed on surface 21a, which is the opposite side of the transmitted light incident surface in the target object 20; and ST inspection, used to check for cracks 14 not exposed on surface 21a or back surface 21b of the target object 20.

[0092] The GUI10 receives input related to the type of processing conditions for laser processing of the target object 20. The control unit 9 switches the correction amounts for aberration correction in the first interval, the second interval, and the third interval based on the input received by the GUI10 related to the type of processing conditions. Examples of processing conditions include, for instance, the SDBG condition where a modified region 12 is formed inside the target object 20 and the target object 20 is thinned by grinding; and the FC condition where cracks 14 and modified regions 12 are formed from the surface 21a to the back surface 21b of the target object 20. Other examples of processing conditions include MEMS conditions where processing is performed under FC conditions to reduce end-face unevenness for particle suppression; memory conditions where processing is performed under SDBG conditions to ensure device quality such as the straightness of lower cracks and damage suppression; and device conditions set according to the type of device or the quality required by the user.

[0093] The GUI10 receives input related to the thickness of the target object 20. Based on the input related to the thickness of the target object 20 received by the GUI10, the control unit 9 switches the correction amount for aberration correction in the first interval, aberration correction in the second interval, and aberration correction in the third interval.

[0094] The GUI10 receives input related to either the simple input mode or the detailed input mode. When the GUI10 receives input related to the detailed input mode as the input mode, it receives inputs of correction amounts for aberration correction in the first, second, and third intervals. The control unit 9 switches these correction amounts based on the inputs received by the GUI10. When the GUI10 receives input related to the detailed input mode as the input mode, it receives input related to the range of the first, second, and third intervals. The control unit 9 switches between the first, second, and third intervals based on the inputs received by the GUI10 related to the range of the first, second, and third intervals.

[0095] Figures 9(a) and 9(b) are examples of data tables showing the correction amounts related to aberration correction for the first, second, and third intervals. Figure 9(a) is a data table used when the inspection content is FC inspection. Figure 9(b) is a data table used when the processing conditions are SDBG conditions. "-" indicates that no observation is performed, or the correction amount for aberration correction is not particularly limited (arbitrary correction amount). In the figures, "0mm correction", "0.1mm correction", "0.2mm correction", "0.4mm correction", and "0.8mm correction" represent the correction amounts for aberration correction, with the correction amounts increasing sequentially. "0mm correction", "0.1mm correction", "0.2mm correction", "0.4mm correction", and "0.8mm correction" can be achieved by appropriately rotating the correction rings 47x, 47y, and 47z in the first aberration correction section 47A, the second aberration correction section 47B, and the third aberration correction section 47C. For example, "0.8mm correction" refers to the minimum correction amount for spherical aberration at a depth of 0.8mm inside the target object 20. The parentheses in the figure indicate that corrections can also be made according to the correction amount within the parentheses. These explanations are the same below.

[0096] For example, when the control unit 9 receives an input from the GUI 10 to set the inspection content to FC inspection, it can also use the data sheet shown in FIG. 9(a) to switch the correction amount of aberration correction for the first to third zones based on the input related to the thickness of the target object 20 received by the GUI 10. Similarly, when the control unit 9 receives an input from the GUI 10 to set the processing conditions to SDBG conditions, it can also use the data sheet shown in FIG. 9(b) to switch the correction amount of aberration correction for the first to third zones based on the input related to the thickness of the target object 20 received by the GUI 10.

[0097] Figure 10 is an example of the input screen 10a of the GUI 10 when observing the target object 20. In the example shown in Figure 10, in the input screen 10a of the GUI 10, the user selects "Non" for processing and inputs "Before laser processing". In addition, in the input screen 10a of the GUI 10, the user selects "FC inspection" for the inspection content, selects "Simple input mode" for the input mode, and selects "400 μm" for the thickness of the target object 20.

[0098] Based on the input from GUI10, control unit 9 uses, for example, a pre-set data table to determine the laser processing conditions, and displays the determined laser processing conditions as "Laser Processing Conditions (Program)" on input screen 10a. For example, control unit 9 determines the laser processing conditions. The procedure includes the number of channels (the number of columns in the thickness direction of the formed modified region 12), the processing Z position (the position of each column of the modified region 12 in the Z direction), and the processing energy (the energy of the laser light L), etc.

[0099] Furthermore, based on the input from GUI10, control unit 9, for example, uses a pre-set data table to switch the correction amounts for aberration correction in the first, second, and third intervals. For example, control unit 9 switches to "0mm correction" as the correction amount for the first interval, to "0.2mm correction" as the correction amount for the second interval, and to "0.4mm correction" as the correction amount for the third interval. Additionally, control unit 9, based on the switching of the correction amounts for the first, second, and third intervals, uses, for example, a pre-set data table to switch the correction coefficients for each of the three intervals. For example, the control unit 9 switches to "0mm correction factor" as the correction factor when performing aberration correction for the first interval, switches to "0.2mm correction factor" as the correction factor when performing aberration correction for the second interval, and switches to "0.4mm correction factor" as the correction factor when performing aberration correction for the third interval. Then, the control unit 9 displays the correction amount and correction factor after the switch on the input screen 10a.

[0100] Furthermore, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the ranges of the first, second, and third intervals, and displays the switched first, second, and third intervals on the input screen 10a. Additionally, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the observation order when observing the first, second, and third intervals, and displays the switched observation order on the input screen 10a.

[0101] Furthermore, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the inspection items (judgment items) for aberration correction in the first, second, and third intervals, and displays the switched inspection items on the input screen 10a. In the figure, "HC / ST" refers to the presence or absence of cracks 14 exposed on the light incident surface of the target object 20, and "BHC / ST" refers to the presence or absence of cracks 14 on the opposite side of the light incident surface of the target object 20. In addition, in the example shown in Figure 10, because it is a simplified input mode, although the laser processing conditions, the correction amount for aberration correction in the first to third intervals, the range of the first to third intervals, the observation order, and the inspection items are displayed on the input screen 10a, the user cannot change or input them.

[0102] Figure 11 is a diagram showing another example of the input screen 10a of the GUI 10 when observing the target object 20. In the example shown in Figure 11, in the input screen 10a of the GUI 10, the user selects "Completed" for processing and inputs "After laser processing". In addition, in the input screen 10a of the GUI 10, the user selects "BHC inspection" for the inspection content, selects "detailed input mode" for the input mode, and selects "775 μm" for the thickness of the target object 20.

[0103] Based on the input from GUI10, control unit 9, for example, uses a pre-set data table to determine the laser processing conditions based on the input, and displays the determined laser processing conditions as "Laser Processing Conditions (Completed)" on input screen 10a. Furthermore, based on the input from GUI10, control unit 9, for example, uses a pre-set data table to switch the correction amounts for aberration correction in the first, second, and third intervals. For example, control unit 9 switches to "any correction amount" as the correction amount for the first interval, switches to "any correction amount" as the correction amount for the second interval, and switches to "0.8mm correction" as the correction amount for the third interval. Additionally, control unit 9, for example, uses a pre-set data table to switch the correction coefficients for each of the three intervals of aberration correction, based on the switching of the correction amounts for the first, second, and third intervals. For example, the control unit 9 switches to "0.8mm correction factor" as the correction factor when performing aberration correction for the third interval. Then, the control unit 9 displays the correction amount and correction factor after the switch on the input screen 10a.

[0104] Furthermore, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the range of the first, second, and third intervals based on the input, and displays the switched first, second, and third intervals on the input screen 10a. Additionally, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the observation order when observing the first, second, and third intervals based on the input, and displays the switched observation order on the input screen 10a.

[0105] Furthermore, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the inspection items for aberration correction in the first, second, and third intervals, and displays the switched inspection items on the input screen 10a. In addition, in the example shown in Figure 11, because it is a detailed input mode, the user can change or input the laser processing conditions, the correction amount for aberration correction in the first to third intervals, the range of the first to third intervals, the observation order, and the inspection items on the input screen 10a.

[0106] Figure 12 is an example of the input screen 10a of the GUI 10 when observing the target object 20 for setting processing conditions (so-called condition setting). In the example shown in Figure 12, in the input screen 10a of the GUI 10, the user selects "Non" for processing and inputs "Before laser processing". In addition, in the input screen 10a of the GUI 10, the user selects "SDBG condition" for processing conditions, selects "Simple input mode" for input mode, and selects "775 μm" for the thickness of the target object 20.

[0107] Based on the input from GUI10, the control unit 9, for example, uses a pre-set data sheet to determine the laser processing conditions based on the input, and displays the determined laser processing conditions as "Laser Processing Conditions (Scheme)" on the input screen 10a. Furthermore, based on the input from GUI10, the control unit 9, for example, uses a pre-set data sheet to switch the required quality based on the input, and displays the switched required quality on the input screen 10a. Examples of required quality include, for instance, an end-face unevenness of less than 10 μm, BHC straightness of less than 6 μm, and a particle suppression level of a specified level (or unlimited). BHC straightness corresponds to the width of the crack 14 on the opposite side of the transmitted light incident surface exposed in the target object 20 when it meanders.

[0108] Furthermore, based on the input from GUI10, control unit 9, for example, uses a pre-set data table to switch the correction amounts for aberration correction in the first, second, and third intervals. For example, control unit 9 switches to "any correction amount" as the correction amount for the first interval, to "any correction amount" as the correction amount for the second interval, and to "0.8mm correction" as the correction amount for the third interval. Additionally, based on the switching of the correction amounts for the first, second, and third intervals, control unit 9, for example, uses a pre-set data table to switch the correction coefficients for each of the three intervals. For example, control unit 9 switches to "0.8mm correction coefficient" as the correction coefficient for the third interval. Then, control unit 9 displays the switched correction amounts and correction coefficients on input screen 10a.

[0109] Furthermore, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the range of the first, second, and third intervals based on the input, and displays the switched first, second, and third intervals on the input screen 10a. Additionally, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the observation order when observing the first, second, and third intervals based on the input, and displays the switched observation order on the input screen 10a.

[0110] Furthermore, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the inspection items for aberration correction in the first, second, and third intervals, and displays the switched inspection items on the input screen 10a. In the example shown in Figure 12, because it is a simplified input mode, although the laser processing conditions, required quality, correction amounts for aberration correction in the first to third intervals, ranges of the first to third intervals, observation order, and inspection items are displayed on the input screen 10a, the user cannot change or input these information.

[0111] Figure 13 is a diagram showing another example of the input screen 10a of the GUI 10 when observing the target object 20 for setting processing conditions. In the example shown in Figure 13, in the input screen 10a of the GUI 10, the user selects "Completed" for processing and inputs "After laser processing". In addition, in the input screen 10a of the GUI 10, the user selects "MEMS Conditions" for processing conditions, selects "Detailed Input Mode" for input mode, and selects "400 μm" for the thickness of the target object 20.

[0112] Based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to determine the laser processing conditions based on the input, and displays the determined laser processing conditions as "Laser Processing Conditions (Completed)" on the input screen 10a. Additionally, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the required quality based on the input, and displays the switched required quality on the input screen 10a.

[0113] Furthermore, based on the input from GUI10, control unit 9, for example, uses a pre-set data table to switch the correction amounts for aberration correction in the first, second, and third intervals. For example, control unit 9 switches to "0mm correction" as the correction amount for the first interval, to "0.2mm correction" as the correction amount for the second interval, and to "0.4mm correction" as the correction amount for the third interval. Additionally, control unit 9, based on the switching of the correction amounts for the first, second, and third intervals, uses, for example, a pre-set data table to switch the correction coefficients for each of the three intervals. For example, the control unit 9 switches to "0mm correction factor" as the correction factor when performing aberration correction for the first interval, switches to "0.2mm correction factor" as the correction factor when performing aberration correction for the second interval, and switches to "0.4mm correction factor" as the correction factor when performing aberration correction for the third interval. Then, the control unit 9 displays the correction amount and correction factor after the switch on the input screen 10a.

[0114] Furthermore, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the range of the first, second, and third intervals based on the input, and displays the switched first, second, and third intervals on the input screen 10a. Additionally, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the observation order when observing the first, second, and third intervals based on the input, and displays the switched observation order on the input screen 10a.

[0115] Furthermore, based on the input from GUI10, the control unit 9, for example, uses a pre-set data table to switch the inspection items for aberration correction in the first, second, and third intervals, and displays the switched inspection items on the input screen 10a. In addition, in the example shown in Figure 13, because it is a detailed input mode, the user can change or input laser processing conditions, required quality, correction amounts for aberration correction in the first to third intervals, the range of the first to third intervals, the observation order, and inspection items on the input screen 10a. For example, if the user changes the required quality, the inspection items change accordingly, and consequently, the correction amounts for aberration correction in the first to third intervals also change.

[0116] Next, referring to the flowchart in FIG14 and the schematic cross-sectional view in FIG15, the process for observing the target object 20 will be described. In addition, in FIG15, for ease of explanation, the cross-section of the target object 20 during back reflection observation is shown as an imaginary cross-section, and the area of ​​the imaginary cross-section is included in the third division (the same in FIG19 and FIG20).

[0117] In the input screen 10a of GUI10, the user makes input as shown in FIG10. The correction ring 47x of the first aberration correction unit 47A is rotated appropriately, and the first correction amount is set to "0mm correction". The correction ring 47y of the second aberration correction unit 47B is rotated appropriately, and the second correction amount of the second aberration correction unit 47B is set to "0.2mm correction". The correction ring 47z of the third aberration correction unit 47C is rotated appropriately, and the third correction amount of the third aberration correction unit 47C is set to "0.4mm correction". In this case, the control unit 9 performs the next processing.

[0118] First, the rotator 48 is rotated with the first condenser lens 43A positioned on the optical axis of the transmitted light I1, switching the aberration correction amount performed by the aberration correction unit 46 to the first correction amount implemented by the first aberration correction unit 47A (step S1). Corresponding to switching the correction amount to the first correction amount, the correction coefficient is switched to the correction coefficient corresponding to the first correction amount (step S2). Next, the height is set (step S3). In step S3, for example, the second vertical movement mechanism 7B is controlled by the control unit 9 to move the observation unit 4 along the Z direction, so that the focusing position of the transmitted light I1 is located on the back surface 21b, which serves as the incident surface of the transmitted light, and this position is set as the reference position.

[0119] Next, the observation unit 4 performs internal observation of the first section of the target object 20, acquiring a plurality of internal images (step S4). In step S4, for example, using the second vertical movement mechanism 7B, the reference position set in step S3 is used as a reference to move the observation unit 4 along the Z direction, aligning the focusing position of the transmitted light I1 with a plurality of positions of the first section of the target object 20 to capture images of the target object 20, acquiring a plurality of internal images. The "depth position information obtained by multiplying the Z-direction movement of the observation unit 4 by a correction coefficient" is correlated with each of the plurality of internal images and obtained as imaging data. The internal observation of the first section here is a direct observation.

[0120] Next, the rotator 48 is rotated with the second condenser lens 43B positioned on the optical axis of the transmitted light I1, switching the aberration correction amount performed by the aberration correction unit 46 to the second correction amount implemented by the second aberration correction unit 47B (step S5). Corresponding to switching the correction amount to the second correction amount, the correction coefficient is switched to the correction coefficient corresponding to the second correction amount (step S6). Next, the height is set in the same manner as in step S3 (step S7).

[0121] Next, the observation unit 4 performs internal observation of the second section of the target object 20, acquiring a plurality of internal images (step S8). In step S4, for example, using the second vertical movement mechanism 7B, the reference position set in step S8 is used as a reference, and the observation unit 4 is moved along the Z direction, so that the focusing position of the transmitted light I1 is aligned with a plurality of positions in the second section of the target object 20 to capture images of the target object 20, acquiring a plurality of internal images. The depth position information obtained by multiplying the Z-direction movement of the observation unit 4 by a correction coefficient is correlated with each of the plurality of internal images and acquired as imaging data. The internal observation of the second section here is a direct observation.

[0122] Next, the rotator 48 is rotated with the third focusing lens 43C positioned on the optical axis of the transmitted light I1, switching the aberration correction amount performed by the aberration correction unit 46 to the third correction amount implemented by the third aberration correction unit 47C (step S9). Corresponding to switching the correction amount to the third correction amount, the correction coefficient is switched to the correction coefficient corresponding to the third correction amount (step S10). Next, the height is set (step S11). In step S11, for example, the observation unit 4 is moved along the Z direction by the control unit 9 controlling the operation of the second vertical movement mechanism 7B, so that the focusing position of the transmitted light I1 is located on the back surface 21b, and this position is set as the reference position. In addition, in step S11, the observation unit 4 is moved along the Z direction by the control unit 9 controlling the operation of the second vertical movement mechanism 7B, so that the focusing position of the transmitted light I1 is located on the surface 21a, and this position is set as another reference position.

[0123] Next, the observation unit 4 performs internal observation of the third section of the target object 20, acquiring multiple internal images (step S12). In step S12, for example, using the second vertical movement mechanism 7B, the reference position set in step S11 is used as a reference to move the observation unit 4 along the Z direction, aligning the focusing position of the transmitted light I1 with multiple positions of the third section of the target object 20 to capture images of the target object 20, acquiring multiple internal images. The "depth position information obtained by multiplying the movement amount of the observation unit 4 in the Z direction by a correction coefficient" is correlated with each of the multiple internal images and obtained as imaging data. The internal observation of the second section here includes direct observation and back reflection observation.

[0124] The above observations, based on the video data acquired in step S4, use the aforementioned AI judgment to determine the internal state of the first region, and detect the presence or absence of HC and the state of the dent based on the judgment result. Based on the video data acquired in step S8, the aforementioned AI judgment is used to determine the internal state of the second region, and the state of the dent is checked based on the judgment result. Based on the video data acquired in step S12, the aforementioned AI judgment is used to determine the internal state of the third region, and the presence or absence of BHC and the state of the dent are detected based on the judgment result.

[0125] Next, referring to the flowcharts in Figures 16, 17, and 18 and the schematic cross-sectional views in Figures 19 and 20, the process of observing for determining processing conditions will be explained.

[0126] In the input screen 10a of GUI10, the user performs the same input as shown in FIG10. Here, the viewing order is set to input "third interval", "first interval" and "all intervals (first to third intervals)" in sequence in the input screen 10a. The correction ring 47x of the first aberration correction unit 47A is rotated appropriately, and the first correction amount is set to "0mm correction". The correction ring 47y of the second aberration correction unit 47B is rotated appropriately, and the second correction amount of the second aberration correction unit 47B is set to "0.2mm correction". The correction ring 47z of the third aberration correction unit 47C is rotated appropriately, and the third correction amount of the third aberration correction unit 47C is set to "0.4mm correction". In this case, the control unit 9 performs the next processing.

[0127] First, as shown in FIG19(a), in the third region of the target object 20 on the stage 2, the laser processing described above is performed by the laser processing head 3 based on the set processing conditions to form the modified region 12 and the crack 14 (step S21). The stage 2, the first horizontal movement mechanism 8A and the second horizontal movement mechanism 8B are controlled by the control unit 9 to move the stage 2 toward the position where the interior of the target object 20 can be observed by the observation unit 4 (hereinafter also referred to as the "observation system") (step S22).

[0128] Next, the rotator 48 is rotated with the third condenser lens 43C positioned on the optical axis of the transmitted light I1, switching the aberration correction amount performed by the aberration correction unit 46 to the third correction amount implemented by the third aberration correction unit 47C (step S23). Corresponding to switching the correction amount to the third correction amount, the correction coefficient is switched to the correction coefficient corresponding to the third correction amount (step S24).

[0129] Next, the height is set (step S25). In step S25, for example, the control unit 9 controls the operation of the second vertical movement mechanism 7B to move the observation unit 4 along the Z direction, so that the focusing position of the transmitted light I1 is located on the back surface 21b, and this position is set as the reference position. Alternatively, in step S25, the control unit 9 controls the operation of the second vertical movement mechanism 7B to move the observation unit 4 along the Z direction, so that the focusing position of the transmitted light I1 is located on the surface 21a, and this position is set as another reference position.

[0130] Next, the observation unit 4 performs internal observation of the third section of the target object 20, acquiring multiple internal images (step S26). In step S26, for example, using the second vertical movement mechanism 7B, the observation unit 4 is moved along the Z direction using the reference position set in step S25 as a reference, so that the focusing position of the transmitted light I1 is aligned with multiple positions of the third section of the target object 20 to capture images of the target object 20, acquiring multiple internal images. The "depth position information obtained by multiplying the movement amount of the observation unit 4 in the Z direction by a correction coefficient" is correlated with each of the multiple internal images and obtained as imaging data. The internal observation of the third section here includes direct observation and back reflection observation.

[0131] Next, the control unit 9 determines the internal state of the third zone based on the camera data acquired in step S26 (step S27). For example, in step S27, the AI ​​determination described above determines that the internal image of the inspection object (modified area 12 and crack 14) in the third zone is relatively clear, and the depth position of the inspection object is calculated by multiplying the movement of the observation unit 4 at this time by a correction factor. Based on the internal image and depth position of the inspection object in the third zone, it is determined whether it meets the required quality corresponding to the user's input based on the GUI 10 (see Figure 10). If the required quality is not met, it is determined that the internal state of the third zone is abnormal (no in step S28), the set processing conditions are changed, and the process returns to step S21 described above. On the other hand, if the required quality is met, the internal state of the third zone is determined to be normal (yes in step S28). The control unit 9 controls the stage 2, the first horizontal movement mechanism 8A and the second horizontal movement mechanism 8B to move the stage 2 toward the position where the laser processing head 3 can perform laser processing on the target object 20 (hereinafter also referred to as the "laser processing system") (step S29).

[0132] Next, as shown in FIG19(b), in the first region of the target object 20 on the stage 2, based on the set processing conditions, the laser processing head 3 performs the aforementioned laser processing to form the modified region 12 and the crack 14 (step S30). The stage 2, the first horizontal movement mechanism 8A, and the second horizontal movement mechanism 8B are controlled by the control unit 9 to move the stage 2 toward the observation system (step S31). The rotator 48 is rotated with the first condenser lens 43A positioned on the optical axis of the transmitted light I1, and the correction amount of the aberration correction performed by the aberration correction unit 46 is switched to the first correction amount implemented by the first aberration correction unit 47A (step S32). Corresponding to the fact that the correction amount has been switched to the first correction amount, the correction coefficient is switched toward the "correction coefficient corresponding to the first correction amount" (step S33).

[0133] Next, the height is set (step S34). For example, in step S34, the control unit 9 controls the operation of the second vertical movement mechanism 7B to move the observation unit 4 along the Z direction, so that the focusing position of the transmitted light I1 is located on the back surface 21b, and this position is set as the reference position. Next, the observation unit 4 performs internal observation of the first section of the target object 20 and acquires a plurality of internal images (step S35). For example, in step S35, the second vertical movement mechanism 7B uses the reference position set in step S34 as a reference, moves the observation unit 4 along the Z direction, and aligns the focusing position of the transmitted light I1 with a plurality of positions in the first section of the target object 20 to capture images of the target object 20, acquiring a plurality of internal images. The "depth position information obtained by multiplying the movement amount of the observation unit 4 in the Z direction by a correction coefficient" is associated with each of the plurality of internal images and acquired as imaging data. The internal observation of the first section here is direct observation.

[0134] Next, the control unit 9 determines the internal state of the first section based on the camera data acquired in step S35 (step S36). For example, in step S36, the AI ​​determination described above determines that the internal image of the object to be inspected in the first section is relatively clear, and the depth position of the object to be inspected is calculated by multiplying the movement of the observation unit 4 at this time by a correction factor. Based on the internal image and depth position of the object to be inspected in the first section, it is determined whether it meets the required quality corresponding to the input from the user based on the GUI 10 (see Figure 10). If the required quality is not met, it is determined that the internal state of the first section is abnormal (no in step S37), the set processing conditions are changed, and the process returns to step S29. On the other hand, if the required quality is met, it is determined that the internal state of the first section is normal (yes in step S37), and the control unit 9 controls the stage 2, the first horizontal movement mechanism 8A, and the second horizontal movement mechanism 8B to move the stage 2 toward the laser processing system (step S38).

[0135] Next, as shown in FIG20, in all regions (first to third regions) of the target object 20 on the stage 2, the laser processing head 3 performs the aforementioned laser processing based on the set processing conditions to form the modified region 12 and the crack 14 (step S39). The stage 2, the first horizontal movement mechanism 8A and the second horizontal movement mechanism 8B are controlled by the control unit 9 to move the stage 2 toward the observation system (step S40). The rotator 48 is rotated with the first condenser lens 43A positioned on the optical axis of the transmitted light I1, and the correction amount of the aberration correction performed by the aberration correction unit 46 is switched to the first correction amount implemented by the first aberration correction unit 47A (step S41). Corresponding to the fact that the correction amount has been switched to the first correction amount, the correction coefficient is switched to the "correction coefficient corresponding to the first correction amount" (step S42). The height is set in the same way as in step S34 (step S43). Similar to step S35, the observation unit 4 performs internal observation of the first interval of the target object 20 to obtain a plurality of internal images (step S44).

[0136] Next, the rotator 48 is rotated with the second condenser lens 43B positioned on the optical axis of the transmitted light I1, switching the aberration correction amount performed by the aberration correction unit 46 to the second correction amount implemented by the second aberration correction unit 47B (step S45). Corresponding to the fact that the correction amount has been switched to the second correction amount, the correction coefficient is switched to the "correction coefficient corresponding to the first correction amount" (step S46). The height is set in the same way as in step S34 (step S47). The observation unit 4 performs internal observation of the second section of the target object 20 and acquires a plurality of internal images (step S48). For example, in step S48, the observation unit 4 is moved along the Z direction by using the second vertical movement mechanism 7B, with the reference position at the height setting in step S47 as a reference, so that the condenser position of the transmitted light I1 is aligned with a plurality of positions in the second section of the target object 20 to capture images of the target object 20 and acquire a plurality of internal images. The depth position information obtained by multiplying the Z-direction movement of observation unit 4 by a correction factor is correlated with each of the multiple internal images and obtained as photographic data. The internal observation of the second interval here is direct observation.

[0137] Next, the rotator 48 is rotated with the third condenser lens 43C positioned on the optical axis of the transmitted light I1, switching the aberration correction amount performed by the aberration correction unit 46 to the third correction amount implemented by the third aberration correction unit 47C (step S49). Corresponding to the fact that the correction amount has been switched to the third correction amount, the correction coefficient is switched to the "correction coefficient corresponding to the third correction amount" (step S50). The height is set in the same manner as in step S25 (step S51). In the same manner as in step S26, the internal observation of the third region of the target object 20 is performed by the observation unit 4, and a plurality of internal images are acquired (step S52).

[0138] Then, the control unit 9 determines the internal state of all zones based on the camera data acquired in steps S44, S48, and S52 (step S53). For example, in step S53, the AI ​​determination described above determines the relatively clear internal images of the inspection objects (modified areas 12 and cracks 14) in all zones, and calculates the depth position of the inspection objects by multiplying the movement of the observation unit 4 at this time by a correction factor. Based on the internal images and depth positions of the inspection objects in all zones, it is determined whether they meet the required quality corresponding to the user's input based on the GUI 10 (see Figure 10). If the required quality is not met, it is determined that the internal state of all zones is abnormal (no in step S54), the set processing conditions are changed, and the process returns to step S39. On the other hand, if the required quality is met, it is determined that the internal state of all zones is normal (yes in step S54), and the process ends.

[0139] In the observation device 100, the area observed in the target object 20 is divided into three high-importance areas: the first to the third area (i.e., the side of the target object 20 with transmitted light incident surface, the interior, and the side opposite to the side with transmitted light incident surface). When observing these first to third areas, aberration corrections can be performed on each of them using correction amounts that switch according to user input. Accordingly, the correction amount can be switched according to user input for optimization, and compared to "optimizing the correction amount every time observation is performed," the frequency of switching can be suppressed to maintain a high production rate. That is, both "high production rate" and "accurate observation of the target object 20" can be achieved.

[0140] In the observation device 100, the aberration correction unit 46 is configured to switch the aberration correction amount between at least a first correction amount, a second correction amount, and a third correction amount. The control unit 9 switches the aberration correction amounts for the first interval, the second interval, and the third interval among the first, second, and third correction amounts based on input received from the GUI 10. In this case, switching between the aberration correction amounts for the first interval, the second interval, and the third interval can be easily achieved.

[0141] In the observation device 100, the transmitted light condenser lens 43 includes a first condenser lens 43A, a second condenser lens 43B, and a third condenser lens 43C. The aberration correction unit 46 includes a first aberration correction unit 47A disposed on the first condenser lens 43A, a second aberration correction unit 47B disposed on the second condenser lens 43B, a third aberration correction unit 47C disposed on the third condenser lens 43C, and a rotator 48. In this case, the transmitted light condenser lens 43 on the optical axis of the transmitted light I1 is switched between the first and third condenser lenses 43A and 43C by using the rotator 48, thereby switching the correction amounts for aberration correction in the first, second, and third regions between the first and third correction amounts.

[0142] In the observation device 100, the first correction value is smaller than the second correction value, and the second correction value is smaller than the third correction value. The correction value can be optimized using the first to third correction values ​​with such a size relationship.

[0143] In the observation device 100, the aberration correction in the first interval can also be used to check the presence or absence of cracks 14 on the transmitted light incident surface exposed in the target object 20. The aberration correction in the second interval can also be used to check the aberration correction of the modified region 12 formed inside the target object 20. The aberration correction in the third interval can also be used to check the presence or absence of cracks 14 on the opposite side of the transmitted light incident surface exposed in the target object 20, i.e., surface 21a. In this case, it is possible to check with high precision whether the target object 20 has HC, the modified region 12 formed inside the target object 20, and whether the target object 20 has BHC.

[0144] Furthermore, when the observation unit 4 is moved along the Z direction by a movement amount Fz to adjust the position of the focusing point of the transmitted light I1 inside the target object 20, a deviation sometimes occurs within this movement amount Fz. One possible cause is the observation position shift due to focusing blurring of the transmitted light focusing lens 43. Additionally, another cause of the deviation within the movement amount Fz is the shift before and after the operation of the so-called correction ring lens. That is, when the transmitted light focusing lens 43 has correction rings 47x, 47y, and 47z, the operation amount of the correction rings 47x, 47y, and 47z relative to the aberration correction amount is sometimes not constant. As a result, the observation position sometimes shifts before and after the operation of the correction rings 47x, 47y, and 47z. Furthermore, mechanical differences in the transmitted light focusing lens 43 of the observation unit 4, or its installation and removal, also contribute to the deviation in the movement amount Fz. If the depth position of the detected target is calculated by multiplying the deviationed movement amount Fz by a certain correction factor, the calculated result also becomes biased. Therefore, in the observation device 100, in order to obtain the accurate depth position of the detected target and to use an appropriate correction coefficient, the correction coefficient is switched according to the switching of the correction amount for the first interval, the second interval, and the third interval. Accordingly, the depth position of the detected target in the target object 20 can be obtained with high precision.

[0145] In the observation device 100, the GUI 10 receives input related to the inspection content of the target object 20. The control unit 9 switches the correction amounts for aberration correction in the first, second, and third regions based on the input received from the GUI 10 related to the inspection content. In this case, the correction amounts for aberration correction in the first, second, and third regions can be optimized based on the user's input related to the inspection content.

[0146] In the observation device 100, the GUI 10 receives input related to the type of processing conditions for laser processing of the target object 20. The control unit 9 switches the correction amounts for aberration correction in the first, second, and third intervals based on the input received from the GUI 10 related to the type of processing conditions. In this case, the correction amounts for aberration correction in the first, second, and third intervals can be optimized based on the user's input related to the type of processing conditions.

[0147] In the observation device 100, the GUI 10 receives input related to the thickness of the target object 20. The control unit 9 switches the correction amounts for aberration correction in the first, second, and third intervals based on the thickness-related input received from the GUI 10. In this case, the correction amounts for aberration correction in the first, second, and third intervals can be optimized based on the user's input related to the thickness of the target object 20.

[0148] In the observation device 100, the GUI 10 receives input related to whether the input mode is a simple input mode or a detailed input mode. When the input mode is a detailed input mode, the GUI 10 receives the correction amounts for aberration correction in the first, second, and third intervals. In this case, by inputting the detailed input mode, the user can input the correction amounts for aberration correction in the first, second, and third intervals.

[0149] Figure 21 is a table showing the relationship between the correction amount of aberration correction and the judgment of various inspection items. In the figure, "〇" indicates that it can be accurately judged, "△" indicates that it can be judged, and "×" indicates that it cannot be judged. HC detection refers to the detection of crack 14 exposed on the transmitted light incident surface of the target object 20. HC meandering refers to the meandering of crack 14 exposed on the transmitted light incident surface of the target object 20. Upper crack detection refers to the detection of the end of crack 14 closest to the transmitted light incident surface inside the target object 20. Dent (direct observation) refers to the detection of dent (modified area 12) based on direct observation. Lower crack detection refers to the detection of the end of crack 14 on the opposite side of the transmitted light incident surface inside the target object 20. Dent (back reflection observation) refers to the detection of dent based on back reflection observation.

[0150] In the example shown in the figure, the thickness of the target object 20 is set to 400 μm. Here, in the thickness direction, the range from the incident surface of the transmitted light to 0.2 mm is defined as the first interval, and in the thickness direction, the range from the opposite side of the incident surface of the transmitted light to 0.2 mm is defined as the third interval. The range inside the target object 20, excluding the first and second intervals, is defined as the second interval. HC detection, HC meandering, and upper crack detection are inspection items that can be determined by observation in the first interval. Dents (direct observation), black stripes, and end face unevenness are inspection items that can be determined by observation in the second interval. Lower crack detection and spring marks (observed from back reflection) are inspection items that can be determined by observation in the third interval. As shown in Figure 21, by distinguishing between the first to third intervals, rather than fixing the amount of aberration correction, accurate determination can be made using multiple inspection items.

[0151] Furthermore, in this embodiment, the second interval side of the first interval and the first interval side of the second interval may repeat each other in the first repeating interval, and the third interval side of the second interval and the second interval side of the third interval may repeat each other in the second repeating interval. In this case, two observations with different aberration correction amounts may be performed in the first repeating interval (an observation with aberration correction in the first interval and an observation with aberration correction in the second interval), and two observations with different aberration correction amounts may also be performed in the second repeating interval (an observation with aberration correction in the second interval and an observation with aberration correction in the third interval). That is, in this case, the control unit 9 can also perform the following imaging processes: performing aberration correction for the first interval by the aberration correction unit 46 while imaging the first repeating interval by the light detection unit 44; performing aberration correction for the second interval by the aberration correction unit 46 while imaging the first repeating interval by the light detection unit 44; performing aberration correction for the second interval by the aberration correction unit 46 while imaging the second repeating interval by the light detection unit 44; and performing aberration correction for the third interval by the aberration correction unit 46 while imaging the second repeating interval by the light detection unit 44. Accordingly, more accurate observation can be performed in the first and second repeating intervals of the target object 20. Furthermore, sometimes, based on input information such as the thickness of the target object 20, accurate observation can also be performed (which can be determined) by only performing aberration correction for the first and third intervals.

[0152] This invention is not limited to the above-described embodiments and can be modified arbitrarily.

[0153] Figure 22 is a perspective view of the observation unit 104 of the first modified example. The observation unit 104 shown in Figure 22 differs from the observation unit 4 described above (see Figure 5) at the point where its light detection section 44 is also used as the light detection section of the alignment camera 5. The observation unit 104 has a rotator 148, and a first condenser lens 43A, a second condenser lens 43B, a third condenser lens 43C, and an alignment lens 5D are mounted at four circumferentially spaced positions on the rotating part 148b of the rotator 148. The rotator 148 arranges any one of the first condenser lens 43A, the second condenser lens 43B, the third condenser lens 43C, and the alignment lens 5D on the optical axis of the transmitted light I1, and the rotator 148 is movable (rotating relative to the fixed part 148a with the rotation axis as the base axis) to switch any one of them arranged on the optical axis of the transmitted light I1.

[0154] The first condenser lens 43A, the second condenser lens 43B, and the third condenser lens 43C are, for example, so-called correction ring lenses with a magnification of 50x. When the light detection unit 44 is used for internal observation, they are positioned on the optical axis of the transmitted light I1 by the drive of the rotator 148. The alignment lens 5D is, for example, a lens with a magnification of 10x (or 20x). When the light detection unit 44 is used for high-magnification alignment, it is positioned on the optical axis of the transmitted light I1 by the drive of the rotator 148. In this variation, the light detection unit 44 is combined for both internal observation and high-magnification alignment, which has the effect of reducing costs.

[0155] Figure 23 is a perspective view of the observation unit 204 in the second modified example. Similar to the observation unit 104 described above (see Figure 22), the observation unit 204 shown in Figure 23 uses its light detection unit 44 as the light detection unit of the alignment camera 5. The observation unit 204 has a linear motion stage 248. In the linear motion stage 248, a first condenser lens 43A, a second condenser lens 43B, a third condenser lens 43C, and an alignment lens 5D are mounted at four equally spaced positions along the X or Y direction. The linear motion stage 248 positions any one of the first condenser lens 43A, the second condenser lens 43B, the third condenser lens 43C, and the alignment lens 5D on the optical axis of the transmitted light I1, and the linear motion stage 248 is movable (moving linearly along the X or Y direction) to switch the position of any one of them on the optical axis of the transmitted light I1.

[0156] When the light detection unit 44 is used for internal observation, the first condenser lens 43A, the second condenser lens 43B, and the third condenser lens 43C are positioned on the optical axis of the transmitted light I1 by driving the linear motion stage 248. When the light detection unit 44 is used for high-magnification alignment, the alignment lens 5D is positioned on the optical axis of the transmitted light I1 by driving the linear motion stage 248. In this modified example, the light detection unit 44 is used for both internal observation and high-magnification alignment, thus reducing costs.

[0157] Figure 24 is a schematic diagram showing the structure of the observation unit 304 in the third modified example. The observation unit 304 shown in Figure 24, like the observation unit 104 described above (see Figure 22), uses its light detection unit 44 as the light detection unit for the alignment camera 5. Furthermore, the optical path of the observation unit 304 can be switched by shutters 301A and 301B. Shutters 301A and 301B are, for example, electrically operated mechanical shutters, connected to the control unit 9 (see Figure 1) to control their opening and closing.

[0158] In the observation unit 304, during internal observation, the control unit 9 sets shutter 301A to the closed state and shutter 301B to the open state. In this case, transmitted light I1 passes through the marker RT, is reflected by the semi-reflective mirror 302, passes through the transmitted light condenser lens 43, and illuminates the target object 20 (see Figure 5). The transmitted light I1 reflected by the target object 20 passes through the transmitted light condenser lens 43 and the semi-reflective mirror 302, passes through shutter 301B, is reflected by the total reflection mirror 303, and is reflected by the semi-reflective mirror 314 before being received by the light detection unit 44. On the other hand, in the observation unit 304, during alignment, the control unit 9 sets shutter 301B to the closed state and shutter 301A to the open state. In this case, transmitted light I1 is reflected by the semi-reflective mirror 305, passes through the alignment lens 5D, and illuminates the target object 20. The transmitted light I1 reflected by the target object 20 passes through the alignment lens 5D and the shutter 301A, and then through the semi-reflective mirror 314 before being received by the light detection unit 44.

[0159] The transmitted light condenser lens 43 is, for example, a so-called correction ring lens with a magnification of 50x. The aberration correction amount of the transmitted light condenser lens 43 is switched by rotating its correction ring using the drive unit 310. Alternatively, as shown in FIG22 or FIG23, the transmitted light condenser lens 43 may have first to third condenser lenses 43A to 43C, any one of which is positioned on the optical axis of the transmitted light I1 by driving the rotator 148 or the linear motion stage 248. In the illustrated example, the light source of the transmitted light I1 is separated so that the internal observation marker RT is not projected onto the alignment image.

[0160] In this modified example, the photodetector 44 is also used for internal observation and high-magnification alignment, which has the effect of suppressing costs. Furthermore, since the accuracy in the X, Y, and θ directions is quite important compared to internal observation, the optical path used for alignment needs a structure that "ensures the accuracy in the X, Y, and θ directions." The observation unit 304 can realize a structure that ensures the accuracy in the X, Y, and θ directions.

[0161] Figure 25 is a schematic diagram showing the structure of the observation unit 404 in the fourth modified example. The observation unit 404 shown in Figure 25, like the observation unit 304 described above (see Figure 24), uses its light detection unit 44 as the light detection unit for the alignment camera 5. Furthermore, the optical path of the observation unit 404 can be switched by moving the total reflection mirror 401. The total reflection mirror 401 is connected to the control unit 9 (see Figure 1), and its movement is controlled.

[0162] In the observation unit 404, during internal observation, the total internal reflection mirror 401 is moved by the control unit 9 and positioned in the optical path of the transmitted light I1. In this case, the transmitted light I1 passes through the marker RT, is reflected by the semi-reflecting mirror 402, passes through the transmitted light focusing lens 43, and illuminates the target object 20 (refer to FIG. 5). The transmitted light I1 reflected by the target object 20 passes through the transmitted light focusing lens 43 and the semi-reflecting mirror 402, is reflected by the total internal reflection mirror 403, and is reflected by the total internal reflection mirror 401 before being received by the light detection unit 44. On the other hand, in the observation unit 404, during alignment, the total internal reflection mirror 401 is moved by the control unit 9 to a position away from the optical path of the transmitted light I1. In this case, the transmitted light I1 is reflected by the semi-reflecting mirror 405, passes through the alignment lens 5D, and illuminates the target object 20. The transmitted light I1 reflected by the target object 20 passes through the alignment lens 5D and the semi-reflecting mirror 405 before being received by the light detection unit 44.

[0163] In this modified example, the photodetector 44 is integrated for internal observation and high-magnification alignment, which helps to reduce costs. Furthermore, the observation unit 404 can achieve a structure that ensures accuracy in the X, Y, and θ directions.

[0164] In the above embodiments, the structure of the laser processing apparatus 1 is not limited, and for example, it can also be configured as the laser processing apparatus 101 shown in FIG. 26. The laser processing apparatus 101 differs from the laser processing apparatus 1 of the above embodiments (see FIG. 1) in that it has a first vertical movement mechanism 107A instead of the first vertical movement mechanism 7A (see FIG. 1) and a second vertical movement mechanism 107B instead of the second vertical movement mechanism 7B (see FIG. 1).

[0165] The first vertical movement mechanism 107A is a mechanism that moves the laser processing head 3 along the Z-direction together with the alignment cameras 5 and 6. The first vertical movement mechanism 107A has a first vertical axis 171 disposed on one side of the columnar first base portion 175 in the X-direction. The first base portion 175 is fixed to, for example, a mounting surface. The first vertical axis 171 extends along the Z-direction. The mounting portion 39 of the laser processing head 3 is movably mounted to the first vertical axis 171 along the Z-direction. This first vertical movement mechanism 107A moves the laser processing head 3 along the first vertical axis 171 in the Z-direction by the driving force of a drive source (not shown). There are no particular limitations on the first vertical movement mechanism 107A; various mechanisms can be used as long as they enable the laser processing head 3 to move along the Z-direction.

[0166] The second vertical movement mechanism 107B is a mechanism (moving part) that moves the observation unit 4 along the Z direction. The second vertical movement mechanism 107B has a second vertical axis 172 disposed on the opposite side of the first base portion 175 in the X direction. That is, both the first vertical axis 171 and the second vertical axis 172 are disposed on the first base portion 175 and are configured to face each other via the first base portion 175. The second vertical axis 172 extends along the Z direction. The mounting portion 49 of the observation unit 4 is movably mounted on the second vertical axis 172 along the Z direction. This second vertical movement mechanism 107B moves the observation unit 4 along the second vertical axis 172 in the Z direction by the driving force of a drive source (not shown). There are no particular limitations on the second vertical movement mechanism 107B; various mechanisms can be used as long as they enable the observation unit 4 to move along the Z direction. In the laser processing apparatus 101, a device structure can be realized in which the base portions where the first vertical axis 171 and the second vertical axis 172 are disposed are shared as the first base portion 175.

[0167] In the above embodiments, the aiming cameras 5 and 6 may be able to move along the Z direction coaxially with the laser processing head 3 and the observation unit 4. In the above embodiments, although the "second vertical moving mechanism 7B, 107B that moves the entire observation unit 4 along the Z direction" is used as the moving part, it can also be replaced by using the "actuator that moves the transmitted light focusing lens 43 in the Z direction" or the like as the moving part.

[0168] In the above embodiment, the user input based on GUI10 may include at least one of the aforementioned inputs. Furthermore, the user input based on GUI10 is not limited to the aforementioned inputs; it may also include inputs related to information about other target objects 20, and inputs related to other inspection content. For example, the user-inputted information about target object 20 may include information related to the material of target object 20. Additionally, the user-inputted inspection content may include information related to the status inspection of laser processing apparatus 1, 101, yield inspection, and information related to required quality inspection. In the above embodiment, observation may be performed without rotating the correction rings 47x, 47y, 47z of the first to third condenser lenses 43A, 43B, 43C during the setting process (i.e., keeping them constant). In this case, by rotating the correction rings 47x, 47y, 47z, the correction coefficients will not shift, and it is not necessary to re-output the correction coefficients; therefore, production speed can be improved.

[0169] In the above embodiments, a spatial light modulator disposed on the optical path of the transmitted light I1 may also be used as the aberration correction unit 46. In the above embodiments, the observation device 100 is applied to the laser processing apparatus 1, but it can also be applied to other processing apparatuses. For each structure in the above embodiments and modifications, it is not limited to the materials and shapes described above, and various materials and shapes can be applied. In addition, each structure in the above embodiments and modifications can be arbitrarily applied to each structure in other embodiments or modifications.

[0170] C: Focusing position H3: Frame H4:frame I1: Transmitted light L: Laser light RT: Markings V: Visible light 1: Laser processing equipment 2: Platform 3: Laser processing head 4: Observation Unit 5: Aim the camera 5D: Alignment Lens 6: Aim the camera 7A: First vertical moving mechanism 7B: Second vertical movement mechanism 8A: First horizontal moving mechanism 8B: Second horizontal moving mechanism 9: Control Department 10: GUI (Graphical User Interface) 10a: Input screen 12: Modified Area 14: Cracks 15: Line 20: Target 21: Semiconductor substrate 21a: Surface 21b: Back 21c: Incision 22: Functional Component Layer 22a: Functional element 23: Passage Area 31: Light source 32: Beam Spectroscope 33: Laser light focusing lens 35: Observe the camera 36: Visible light source 37: Beam Spectroscope 38: Lens 39: Installation Department 41: Light source 42: Mirror 43: Transmitting light focusing lens (condensing lens) 43A: First Condensing Lens 43B: Second condenser lens 43C: Third condenser lens 44: Optical Detection Department 46: Aberration Correction Unit 47A: First aberration correction unit 47B: Second aberration correction unit 47C: Third aberration correction unit 47x: Correction ring 47y: Correction ring 47z: Correction ring 48: Rotator 48a: Fixing part 48b: Rotating part 49: Installation Department 71: First vertical axis 72: Second vertical axis 75: First base part 76: Second base part 81: First horizontal axis 82: Second horizontal axis 100: Observation device 101: Laser processing equipment 104: Observation Unit 107A: First vertical moving mechanism 107B: Second Vertical Movement Mechanism 148: Rotator 148a: Fixing part 148b: Rotating part 171: First vertical axis 172: Second vertical axis 175: First base section 204: Observation Unit 248: Linear Moving Platform 301A: Shutter 301B: Shutter 302: Semi-reflective mirror 303: Total Internal Reflection Mirror 304: Observation Unit 305: Semi-reflective mirror 310: Drive Unit 314: Semi-reflective mirror 401: Total Internal Reflection Mirror 402: Semi-reflective mirror 403: Total Internal Reflection Mirror 404: Observation Unit 405: Semi-reflective mirror

Claims

1. An observation device for observing a target object using transmissive light, comprising: a condenser lens that focuses the transmissive light toward the target object; an imaging unit that receives the transmissive light reflected from the target object and captures an image of the target object; a moving unit that moves the condenser lens relative to the target object; an input unit that receives input from a user; an aberration correction unit that performs aberration correction on the transmissive light; and a control unit that controls at least the aberration correction unit, wherein the aberration correction unit is configured to switch the amount of aberration correction, and the control unit can switch the amount of at least one of aberration correction for a first interval, aberration correction for a second interval, and aberration correction for a third interval based on the input received from the input unit: wherein the aberration correction for the first interval is the aberration correction performed by the aberration correction unit when the imaging unit captures an image of a first interval on the incident surface of the transmissive light in the target object; The aforementioned second interval aberration correction is the aberration correction performed by the aforementioned aberration correction unit when the aforementioned camera unit captures the second interval inside the aforementioned target object; the aforementioned third interval aberration correction is the aberration correction performed by the aforementioned aberration correction unit when the aforementioned camera unit captures the third interval on the opposite side of the incident surface of the transmitted light in the aforementioned target object.

2. The observation apparatus as described in claim 1, wherein, The aforementioned aberration correction unit is configured to switch the aberration correction amount between at least a first correction amount, a second correction amount, and a third correction amount. The aforementioned control unit switches the aberration correction amount for the first interval, the aberration correction amount for the second interval, and the aberration correction amount for the third interval among the aforementioned first correction amount, the aforementioned second correction amount, and the aforementioned third correction amount based on the input received by the aforementioned input unit.

3. The observation apparatus as described in claim 2, wherein, The aforementioned condensing lens includes: a first condensing lens, a second condensing lens, and a third condensing lens. The aforementioned aberration correction unit includes: a first aberration correction unit disposed on the aforementioned first condensing lens for implementing the aforementioned first correction amount of aberration correction; a second aberration correction unit disposed on the aforementioned second condensing lens for implementing the aforementioned second correction amount of aberration correction; and a third aberration correction unit disposed on the aforementioned third condensing lens for implementing the aforementioned third correction amount of aberration correction. A rotator is mounted with the aforementioned first condensing lens, the aforementioned second condensing lens, and the aforementioned third condensing lens, and any one of the aforementioned first condensing lens, the aforementioned second condensing lens, and the aforementioned third condensing lens is arranged on the optical axis of the aforementioned transmitted light. The rotator is movable to switch any one of the aforementioned first condensing lens, the aforementioned second condensing lens, and the aforementioned third condensing lens arranged on the optical axis of the aforementioned transmitted light.

4. The observation apparatus as described in claim 2, wherein, The aforementioned first correction amount is less than the aforementioned second correction amount, and the aforementioned second correction amount is less than the aforementioned third correction amount.

5. The observation apparatus as described in claim 3, wherein, The aforementioned first correction amount is less than the aforementioned second correction amount, and the aforementioned second correction amount is less than the aforementioned third correction amount.

6. The observation apparatus as described in claim 1, wherein, The aforementioned first interval aberration correction is used to check for cracks on the incident surface of transmitted light exposed in the aforementioned target object. The aforementioned third interval aberration correction is used to check for cracks on the opposite side of the incident surface of transmitted light exposed in the aforementioned target object.

7. The observation apparatus as described in claim 6, wherein, The aforementioned second interval uses aberration correction, which is used to check the aberration correction of the modified region formed inside the aforementioned target object.

8. The observation apparatus described in any one of claims 1 to 6, wherein, The aforementioned control unit acquires information related to the position of the detection target based on the amount of movement and correction coefficient of the aforementioned condenser lens implemented by the aforementioned movement unit, and switches the aforementioned correction coefficient according to the switching of the correction amount of the aforementioned first interval aberration correction, the aforementioned second interval aberration correction and the aforementioned third interval aberration correction.

9. The observation apparatus described in any one of claims 1 to 6, wherein, The aforementioned input unit receives input related to the content of the inspection performed on the aforementioned target object. The aforementioned control unit switches the correction amounts of the aforementioned first interval aberration correction, the aforementioned second interval aberration correction, and the aforementioned third interval aberration correction based on the input received by the aforementioned input unit related to the content of the inspection.

10. The observation apparatus as described in any one of claims 1 to 6, wherein, The aforementioned input unit receives an input related to the type of processing conditions for laser processing of the aforementioned target object. The aforementioned control unit switches the correction amounts of the aforementioned first interval aberration correction, the aforementioned second interval aberration correction, and the aforementioned third interval aberration correction based on the input related to the type of processing conditions received by the aforementioned input unit.

11. The observation apparatus described in any one of claims 1 to 6, wherein, The aforementioned input unit receives an input related to the thickness of the aforementioned target object. The aforementioned control unit switches the correction amounts of the aforementioned first interval aberration correction, the aforementioned second interval aberration correction, and the aforementioned third interval aberration correction based on the input related to the thickness of the aforementioned target object received by the aforementioned input unit.

12. The observation apparatus described in any one of claims 1 to 6, wherein, The aforementioned input unit receives: receiving input related to whether the input mode is a simple input mode or a detailed input mode, and when receiving input related to the aforementioned detailed input mode as the aforementioned input mode, receiving input of the correction amount for the aforementioned first interval aberration correction, the aforementioned second interval aberration correction, and the aforementioned third interval aberration correction.

13. The observation apparatus described in any one of claims 1 to 6, wherein, The aforementioned second interval side of the first interval and the aforementioned first interval side of the second interval repeat with each other in the first repeating interval. The aforementioned third interval side of the second interval and the aforementioned second interval side of the third interval repeat with each other in the second repeating interval. The aforementioned control unit performs the following: performing aberration correction for the aforementioned first interval by the aforementioned aberration correction unit while performing image processing on the aforementioned first repeating interval by the aforementioned camera unit; performing aberration correction for the aforementioned second interval by the aforementioned aberration correction unit while performing image processing on the aforementioned first repeating interval by the aforementioned camera unit; performing aberration correction for the aforementioned second interval by the aforementioned aberration correction unit while performing image processing on the aforementioned second repeating interval by the aforementioned camera unit; performing aberration correction for the aforementioned third interval by the aforementioned camera unit while performing image processing on the aforementioned second repeating interval.

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