JP6303190B2 - Line camera, inspection device, inspection method for substrate deflection inspection - Google Patents

Description

  The present invention relates to a line camera for substrate deflection inspection, and more specifically to a line camera, an inspection apparatus, and an inspection method for inspecting the deflection of a substrate on which a circuit pattern or the like is formed.

  One of inspections performed in the manufacturing process of semiconductors, liquid crystals, etc. is a macro inspection. Macro inspection means that the surface condition (flatness, unevenness, pattern shape, presence / absence of defects, etc.) of the film provided on the substrate can be visually grasped at once in a wide range including the entire substrate. It is an effective inspection.

  As the degree of integration of circuit patterns formed on a semiconductor wafer such as silicon (hereinafter simply referred to as a wafer) increases, warping and deflection of the wafer as a substrate are obstacles to further miniaturization of the circuit pattern. become. Hereinafter, in this specification, the term “deflection” is used as a general term (in a similar sense) such as “warping”, “deflection”, or “unevenness”. In particular, in the future, the influence of wafer deflection in the vertical direction will become more serious in wafers with larger diameters (450 mm) or three-dimensional mounting (wafer stacking, etc.) performed to increase the degree of integration. . Therefore, it is expected that the importance of inspecting the deflection of the wafer, particularly the deflection of the wafer after the circuit pattern has been formed, on a macro scale over the entire wafer will increase in the future.

  Japanese Laid-Open Patent Publication No. 2011-122935 discloses an inspection method capable of measuring the height of the film edge on the wafer surface. In the inspection method, an image of the boundary portion 11a between the planar portion 11 and the upper bevel portion 12 in the wafer 10 is picked up with the autofocus unit 32 performing the focusing operation and without performing the focusing operation. Then, the height position of the boundary portion 11a with respect to a predetermined reference point in the case where the focusing operation is performed and the case where the focusing operation is not performed is detected from the image data in the vicinity of the end portion of the wafer 10, and the entire circumference of the wafer 10 is detected. By obtaining the height position of the boundary portion 11a, the warpage of the wafer 10 is obtained from the height variation of the boundary portion 11a.

JP 2011-122935 JP

The inspection method disclosed in Patent Document 1 does not macroscopically inspect the deflection of the wafer after the circuit pattern has been formed over the entire wafer, and does not perform the focusing operation. It is set by changing the size.
An object of the present invention is to provide a line camera, an inspection apparatus, or an inspection method for macroscopically inspecting deflection of an entire wafer after a circuit pattern is formed in a relatively simple and high-speed manner. It is.

  The present invention provides a line camera for inspecting the deflection of a substrate on which a circuit pattern is formed. In one aspect of the present invention, the line camera includes a line light source that irradiates light on the surface of the substrate, a line sensor that receives reflected light from a region including the edge of the circuit pattern on the surface of the substrate via a lens, A distance variable mechanism that can vary the distance between the surface of the substrate and the lens from a predetermined value before and after the maximum value of the expected amount of deflection of the substrate can be provided.

  In another aspect of the present invention, the line camera receives, via the first lens, a line light source that irradiates light on the surface of the substrate and reflected light from a region including the edge of the circuit pattern on the surface of the substrate. A first line sensor; and a second line sensor that is adjacent to the first line sensor and receives reflected light from the region of the surface of the substrate via the second lens. The difference between the first distance between the surface of the substrate and the first lens and the second distance between the surface of the substrate and the second lens is around the maximum value of the expected deflection of the substrate. Is set to a predetermined value.

  In another aspect of the present invention, the line camera receives, via the first lens, a line light source that irradiates light on the surface of the substrate and reflected light from a region including the edge of the circuit pattern on the surface of the substrate. A first line sensor, a second line sensor adjacent to the first line sensor and receiving reflected light from the region of the surface of the substrate via the second lens, and the second line sensor And a third line sensor that receives reflected light from the region of the surface of the substrate through the third lens. The first distance D1 between the surface of the substrate and the first lens, the second distance D2 between the surface of the substrate and the second lens, and the surface of the substrate and the third lens The third distance D3 between them has a relationship of D1> D2> D3 or D1 <D2 <D3, and the difference between D1 and D3 is around the maximum value of the expected deflection amount of the substrate.

  In the present invention, the line camera according to any one of the above aspects, a stage on which the substrate can be placed and moved in the horizontal / vertical direction, and a signal from the line camera are received. There is provided a substrate deflection inspection apparatus including a processing apparatus for calculating a deflection amount.

  The present invention further provides a method for inspecting the deflection of a substrate on which a circuit pattern is formed. The method includes irradiating light on a surface of the substrate and receiving reflected light from a region including an edge of a circuit pattern on the surface of the substrate through a lens. The step of receiving includes receiving reflected light from the region at at least two different distances where the distance between the surface of the substrate and the lens is fluctuated around a maximum value of the expected deflection of the substrate. be able to.

  According to the above-described present invention and each aspect thereof, as will be apparent from embodiments of the present invention described later, the circuit pattern is formed with a relatively simple, high-speed, and relatively space-saving configuration. It is possible to macroscopically inspect the deflection of the entire substrate (for example, a wafer) after it is finished.

It is a figure which shows the inspection apparatus of one Embodiment of this invention. It is a figure which shows the light source of one Embodiment of this invention. It is (a) sectional drawing and (b) bottom view which show the line camera of one Embodiment of this invention. It is sectional drawing which shows the line camera of other one Embodiment of this invention. It is sectional drawing which shows the line camera of other one Embodiment of this invention. It is a figure for demonstrating the identification method of the bending in the bending test of one Embodiment of this invention. It is a figure which shows the output signal of the line camera in the deflection inspection of one Embodiment of this invention. It is a figure which shows the deflection inspection flow of one Embodiment of this invention. It is a figure which shows the bending test result of one Embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings. In the following description, the case where a wafer is used as the substrate will be described. However, as with the wafer, other substrates that cause deflection due to the influence of the pattern formed on the surface or the influence of the base material itself are used. Needless to say, the present invention can also be applied.

  FIG. 1 is a diagram showing an inspection apparatus 100 according to an embodiment of the present invention. In FIG. 1, a wafer 20 to be inspected is placed on a circular stage 10. The stage 10 can be moved in the direction of rotation (α), horizontal (X) or vertical (Y) by the linear motor 30 under the control of the stage controller 40.

  The line camera 50 is supported by the distance variable mechanism 60 and is disposed above the stage 10. The line camera 50 is disposed so as to receive reflected light from the surface of the wafer 20 on the stage 10. The distance variable mechanism 60 has a function of changing the position of the line camera 50 in the vertical direction by a predetermined unit. The predetermined unit is set to a value (range) by which the deflection of the wafer 20 can be identified. For example, the vertical position of the line camera 50 can be changed in units of 10 μm to several tens of μm, or 100 μm to several hundreds of μm. . The distance variable mechanism 60 is a vertical type of the line camera 50 according to an arbitrary form such as a manual type in which the cam mechanism is rotated by a handle to replace the movement in the vertical direction, or an electric type using the rotation of a small stepping motor. The position in the direction can be changed by a predetermined unit.

  The line light source 70 is disposed adjacent to the line camera 50 and is set so that light can be irradiated on the surface of the stage 10 from obliquely above. The line light source 70 can be provided adjacent to the line camera 50 integrally with the line camera 50 or separately. The line light sources 70 are arranged substantially in parallel along the longitudinal direction of the line camera 50. The line light source 70 is set at a predetermined angle with respect to the surface of the wafer 20 on the stage 10. The predetermined angle can be arbitrarily set according to the measurement state or the like. The predetermined angle is, for example, in the range of 20 degrees to 80 degrees, and preferably in the range of 30 degrees to 70 degrees. The brightness of the line light source 70 is adjusted by a power source for the light source.

  The output of the line camera 50 is input to the image processing means 80. The image processing means 80 can control the power supply for the stage controller 40, the line camera 50 and the line light source 70. In FIG. 1, only one line light source 70 and one line camera 50 are shown, but two or more line light sources 70 and two line cameras 50 can be arranged. The case where there are two or more line cameras 50 will be further described later. The above is the outline of FIG. Next, details of each component of FIG. 1 will be further described.

  The stage 10 has a size larger than the size of the wafer 20 to be placed, and can have an arbitrary shape other than the circle of FIG. The stage 10 desirably has a surface that is as flat as possible. It is desirable that the stage 10 has a structure in which reflected light from other than the surface of the wafer 20 is hardly generated. The stage 10 is configured so that the wafer 20 can be fixed so that the position of the wafer 20 is not changed when the stage 20 moves with the wafer 20 placed thereon. For example, the stage 10 includes a jig / mechanism (protrusion part, expansion / contraction part, clip part, chuck, etc.) provided on the surface that can restrain the outer periphery 3 and 4 points of the wafer 20 from the outside to the inside.

  As long as various patterns (circuits and wirings (semiconductors, conductors, insulators, etc.)) are basically formed on the surface by a conventional semiconductor process, the wafer 20 to be inspected can be of any configuration (layer structure). A wafer can be selected. The wafer 20 can include either a state in which a large number of IC chips before dicing are formed in a lattice shape or a state in which the above-described various patterns are formed in the middle stage. The wafer 20 can be made of any material such as, for example, Si alone, SOI, SiGe, or a compound semiconductor such as GaAs. The wafer size (diameter) can be any size such as 300 mm or more or less.

  FIG. 2 is a diagram showing a line light source according to an embodiment of the present invention. (A) is a top view of the external shape of the line light source, (b) is a top view of the light emitting source section, and (c) is a cross-sectional view. In (a), the line light source 70 is disposed adjacent to the side of the line camera 50. As shown in the top view of (b), in the line light source 70, for example, a plurality of light emitting elements 72 are arranged in a line at a predetermined pitch L1 on a long substrate. The size of the substrate can be arbitrarily selected, but the length in the longitudinal direction needs to be at least approximately the same as or longer than the length in the longitudinal direction of the line camera 50. The pitch L1 can be arbitrarily selected according to the size of the light emitting element 72 and the like.

  In the cross-sectional view of FIG. 2C, the line light source 70 can include a light emitting source 72 on the line and an optical system (lens, diffuser plate, etc.) 74 for obtaining a diffusion effect thereon. The light emitting element can be basically arbitrarily selected from not only semiconductor elements such as currently available light emitting diodes (LEDs) and laser diodes (LD) but also light emitting elements newly appearing in the future. The line light source 70 is set at a position substantially the same as the height of the line camera 50, for example, at a predetermined distance (for example, 5 to 15 mm) from the wafer surface on the stage 10.

  An optical system (lens, diffusing plate, etc.) 74 for obtaining a diffusing effect such as a diffusing plate is installed integrally with the light emitting source as shown in FIG. can do. A wide wavelength or a predetermined wavelength band can be selected as the wavelength of the light emitting source 72. The selection is performed according to the state of the wafer 20, the optical characteristics (wavelength characteristics, etc.) of the line camera 50 and the optical system.

  FIG. 3 is a diagram showing a line camera 50 according to an embodiment of the present invention. (A) is sectional drawing of a line camera, (b) is a bottom view. The line camera 50 includes a light receiving unit 52 and a lens 54 for guiding light to the light receiving unit 52. The light receiving unit 52 may be anything that can acquire an image for each dimension by arranging light receiving elements (pixels) in a line. For the light receiving part 52, for example, a one-dimensional CCD image sensor or a CMOS image sensor can be used. The number of pixels is selected according to the size of the wafer 20 to be inspected.

  The lens 54 is a cylindrical lens generally called a rod lens, a cell hook lens, or a GRIN lens having a refractive index distribution with a secondary distribution in the radial direction (hereinafter referred to as a rod lens). In the rod lens, since the light incident from the lens end face travels while drawing a sine curve, an equal-magnification erect image can be obtained by setting an appropriate lens length. The plurality of rod lenses are arranged in a row (one-dimensionally) along the light receiving unit 52 in the longitudinal direction of the line camera 50. FIG. 3B shows the bottom surface of one rod lens 54 that is continuous as a set of a plurality of rod lenses. The reflected light received by the lower end portion of each rod lens exits from the upper end portion and is condensed on each corresponding light receiving element (pixel).

  4 and 5 are sectional views showing a line camera according to another embodiment of the present invention. FIG. 4 shows a case where there are two line cameras, and FIG. 5 shows a case where there are three line cameras. Each line camera has the same configuration (specification) as exemplified in FIG. In FIG. 4, the two line cameras 50 </ b> A and 50 </ b> B are arranged with their positions shifted in a direction perpendicular to the surface of the stage 10 (the surface of the wafer 20). 4A shows a case where the line camera 50A on the left side in the horizontal direction is on the lower side and 50B is on the upper side, and FIG. 4B shows the line camera 50B on the left side on the upper side and 50A on the lower side. This is an example of the case.

  The positional deviation amount D between the two line cameras 50A and 50B is around the maximum value of the expected deflection amount of the wafer 20 (for example, maximum value +/− 5 to 10% (maximum value × 0.9 to maximum value × 1). .1 or maximum value × 0.95 to maximum value × 1.05), and so on. For example, when the expected deflection amount of the wafer is +/− 200 μm (maximum width is 400 μm), the positional deviation amount D is set to a predetermined value around 400 μm (for example, 400 μm +/− 5 to 10%, the same applies hereinafter). can do. When the line cameras 50A and 50B have the same configuration (specification), this positional deviation amount D is a distance (working distance) from the surface of the wafer 20 on the stage 10 to the lower surface of the rod lens 54 in each line camera. (WD)).

  That is, in one embodiment of the present invention, the working distance (WD) is changed by changing the positions of the two line cameras 50A and 50B in the vertical direction. In FIG. 4, the vertical positions of the two line cameras 50A and 50B are shifted, but instead, the positions of the two line cameras are the same, and the position of the rod lens 54 included therein is the vertical direction. In this case, the length D may be shifted.

  In FIG. 5, the three line cameras 50 </ b> A, 50 </ b> B, and 50 </ b> C are arranged with their positions shifted in a direction perpendicular to the surface of the stage 10 (the surface of the wafer 20). FIG. 5A shows a case where the positions of the line cameras 50A, 50B, 50C increase in the order from the left side to the right side in the horizontal direction, and FIG. 5B shows the line cameras 50C, 50B, 50B, 50B, from the left side to the right side. This is an example where the position decreases in the order of 50A. The positional deviation amount D1 of the line cameras 50A and 50B and the positional deviation amount D2 of the line cameras 50B and 50C can be basically set to the same length. That is, when the position of the line camera 50B is used as a reference, the other line cameras 50A and 50C are located at positions shifted by a distance D1 (= D2) up and down. It is also possible to set D1 and D2 to different lengths.

  The misregistration amounts D1 and D2 are about the maximum deflection amount (maximum value in the vertical direction) before and after the expected deflection amount of the wafer 20 (for example, each maximum value in the vertical direction +/− 5 to 10%, (maximum value × 0). .9 to maximum value × 1.1, or maximum value × 0.95 to maximum value × 1.05), and so on. For example, when the expected deflection amount of the wafer is +/− 200 μm, the misregistration amounts D1 and D2 are set to predetermined values of about 200 μm (for example, 200 μm +/− 5 to 10%, the same applies hereinafter). Can do. In other words, the total value (D1 + D2) of D1 and D2 can be set to a predetermined value around the maximum width of 400 μm of the total deflection in the vertical direction.

  As in the case of FIG. 4, when the line cameras 50 </ b> A, 50 </ b> B, and 50 </ b> C have the same configuration (specifications), the positional deviation amounts D <b> 1 and D <b> 2 are determined from the surface of the wafer 20 on the stage 10. This corresponds to (becomes equal to) the shift amount of the distance (working distance (WD)) to the lower surface of the rod lens 54. Further, in place of the configuration of FIG. 5, the positions of the three line cameras in the vertical direction are the same, and the position of the rod lens 54 in the two line cameras is the vertical direction by D1 and (D1 + D2). It may be shifted.

  The image processing unit 80 in FIG. 1 processes an inspection signal (flexure information) received from the line camera 50 based on a predetermined measurement program. The image processing means 80 controls the controller 40 and the illumination power source. The image processing means 80 includes a control card (circuit board) for the line camera 50, a controller 40, a circuit board for controlling the illumination power supply, a memory for storing image data, and the like. As the image processing means 80, for example, a personal computer (PC) having a display unit for displaying image processing results, an input unit for inputting measurement conditions, and the like is applicable.

  Next, with reference to FIG. 6 and FIG. 7, a deflection identification / detection method (principle) in a deflection inspection according to an embodiment of the present invention will be described. When the number of the line camera 50 in FIG. 6A is one, it is assumed that there is no deflection at the measurement point (black circle) on the surface of the wafer 20 first, and is in a flat state indicated by symbol A. In this state, it is assumed that the measurement point and the light receiving element in the line camera 50 are in focus (focus, ON). When the position of the surface of the wafer 20 is changed and the wafer 20 is bent upward as indicated by symbol B, or when the wafer 20 is bent downward as indicated by symbol C, the measurement point (black circle) is measured. And the light receiving element in the line camera 50 become out of focus (defocus, NG).

  FIG. 7 is a diagram illustrating an example of a waveform of an output signal from the line camera 50 in the above-described focus (ON) and defocus (NG). FIG. 7 is a diagram showing an output signal at a measurement point (black circle in FIG. 6) when the region including the edge portion of the circuit pattern on the surface of the wafer 20 on the stage 10 moves from the left to the right in the figure. . The signal waveform P1 in FIG. 7 is an example of the output signal waveform when the measurement point and the light receiving element in the line camera 50 are in focus (focus, ON), and the signal waveform P2 is in focus. It is an example of a signal waveform when not (defocused, NG).

  In the case of the signal waveform P1 in FIG. 7, since the focus is achieved, the amount of light incident on the light receiving element is large, and the output signal quickly rises according to the movement of the region including the edge portion of the circuit pattern. On the other hand, in the case of the signal waveform P2, since the focus is not achieved, the amount of light incident on the light receiving element is reduced, and the output signal rises gently according to the movement of the region. As a result, there is a difference between t1 and t2 as shown in FIG. 7 in the time between the preset threshold values S1 and S2, that is, the rise times (response speeds) of the signal waveforms P1 and P2 (t1). <T2). The basic concept (principle) of the present invention is to detect the presence or absence of deflection of the wafer 20 by using the difference (large or small) in the rise time of the signal.

  However, in the case where there is one line camera 50 in FIG. 6A, it is possible to detect the presence or absence of deflection of the wafer 20 using the time difference between the signal rises in FIG. 7, but the deflection is the upper side in the vertical direction. It is not possible to determine whether or not it is a sneaking to the bottom. Therefore, as shown in FIGS. 5 and 6B and 6C, it is necessary that there are two or three line cameras whose vertical positions are shifted. As already described in the description of FIG. 5, the positions of the two or three line cameras in the vertical direction may be the same, and the position of the rod lens in the line camera may be shifted in the vertical direction. . Alternatively, the measurement may be performed using one line camera 50 of FIG. 6A while shifting the position of the line camera in the vertical direction at one measurement point.

  When measurement is performed with the two line cameras 50A and 50B in FIG. 6B, it is assumed that there is no deflection at the measurement point (black circle) on the surface of the wafer 20 and that the measurement is in a flat state indicated by symbol A. In this state, it is assumed that the measurement point and the light receiving element in the lower line camera 50A are in focus (OK). In the state where the position of the surface of the wafer 20 is changed and the wafer 20 is bent upward as indicated by reference numeral B, the focus is defocused between the measurement point (black circle) and the light receiving element in the line camera 50A (NG). ), The measurement point (black circle) and the light receiving element in the upper line camera 50A are in focus (OK).

  In the state where the wafer 20 is bent downward as indicated by reference numeral C, the focus is not achieved between the light receiving elements in the line camera (NG) in either of the line cameras 50A and 50B. As described above with reference to FIG. 4, the line camera position deviation amount D is the expected deflection amount of the wafer 20, as described above with reference to FIG. 4. This is because it is set around the maximum value. By comparing the output signals (signals P1 and P2 in FIG. 7) of the line cameras 50A and 50B in the state of A (flat), B (upper deflection), and C (lower deflection), the wafer is placed on the upper side or the lower side. Can be identified.

  Specifically, from the relationship between the signal waveforms P1 and P2 shown in FIG. 7, the difference (ta−tb) between the rise times ta and tb of the output signals of the line cameras 50A and 50B is negative ( Since ta <tb), the upper deflection state of B is plus (ta> tb), and the lower deflection state of C is almost zero (ta = tb). Therefore, the time difference (ta−tb) ) Can be identified as to whether the wafer is deflected to the upper side or the lower side. When measuring with the two line cameras 50A and 50B in FIG. 6B, it is not necessary to shift the position of the line camera up and down as in the case of one line camera 50 in FIG. 6A. There is an advantage that measurement results can be obtained at high speed.

  Even when measuring with the three line cameras 50A, 50B, and 50C in FIG. 6C, the presence / absence of the deflection of the wafer and the direction of the deflection (up or down) using the rise time of the output signal of each line camera described above. ) Can be detected. Specifically, instead of the method of viewing the time difference shown in FIG. 6B, detection is performed by directly viewing the values of the rise times ta, tb, and tc of the output signals of the line cameras 50A, 50B, and 50C. Can do. That is, in the flat state of A, the rise time tb of the line camera 50B is minimum (tb <ta, tc), and in the state of deflection on the upper side of B, the rise time tc of the line camera 50C is minimum (tc <ta, tb). Since the rise time ta of the line camera 50A is minimized (ta <tb, tc) in the state of the lower side deflection of C, the wafer can be obtained by observing the magnitude relationship (minimum value) of the rise time of each line camera. It can be identified whether it bends up or down. When measuring with the three line cameras 50A and 50B in FIG. 6C, it is not necessary to shift the position of the line camera up and down as in the case of one line camera 50 in FIG. 6A. There is an advantage that measurement results can be obtained at high speed.

  Next, a deflection inspection flow according to an embodiment of the present invention will be described with reference to FIG. FIG. 8 is a diagram showing a deflection inspection flow according to an embodiment of the present invention. The flow of FIG. 8 is executed by the inspection apparatus 100 of the embodiment of FIG.

  In step S10, a substrate is set on the stage 10. As described above, the substrate may include the wafer 20 on which the circuit pattern or the like is formed on the surface. Hereinafter, the case of the wafer 20 will be described. At that time, a jig / mechanism provided on the surface of the stage 10, for example, three or four points on the outer periphery of the wafer 20, so that the position of the wafer 20 does not change when the stage moves. The wafer 20 is fixed to the surface of the stage 10 by a protrusion, an expansion / contraction part, a clip part, a chuck, and the like that can suppress the distance from the outside to the inside. In step S <b> 20, light is irradiated from the line light source 70 to the inspection area on the surface of the wafer 20. As the inspection area, an area including an edge of a predetermined pattern on a predetermined substrate is selected. For example, a region including an edge of a predetermined pattern in each IC chip in the entire wafer 20 is selected.

  In step S <b> 30, the line camera 50 receives reflected light from the surface of the wafer 20 at a first distance from the surface of the wafer 20. In step S <b> 40, the line camera 50 receives reflected light from the surface of the wafer 20 at a second distance from the surface of the wafer 20. In step S <b> 50, the line camera 50 receives reflected light from the surface of the wafer 20 at a third distance from the surface of the wafer 20. As described above, each of the three steps S30 to S50 can be performed by changing the position using one line camera 50 or using the line cameras 50A, 50B, and 50C having three different positions. But you can do it. Further, as described with reference to FIG. 6B, the step S50 is omitted, and the reflected light is received (at two detection distances) by using the two line cameras 50A and 50B. Good.

  In step S60, it is determined whether or not the inspection (measurement) has been completed in all regions to be inspected on the surface of the wafer 20. If the determination is NO, in step S70, after the stage 10 has moved to the inspection area including the next predetermined pattern to be inspected on the surface of the wafer 20, the process returns to step S20, and after the irradiation of light to the inspection area The steps are repeated. If the determination in step S60 is YES, in step S80, the received light data measured by the line camera is processed by the image processing means 80, and information on the deflection (state distribution) on the entire surface of the wafer 20 is obtained.

  The obtained deflection information is displayed as a macro image (map) on the screen of the display device provided in the image processing means 80 in the next step S90. FIG. 9 shows an example of an image of the inspection result. A “+” in a circle that images the wafer 20 indicates that there is an upward deflection, and “−” indicates that there is a downward deflection. The magnitude of the deflection is expressed by changing the magnitude of “+” and “−”, for example. Note that the display in FIG. 9 is merely a simple example, and the deflection distribution is represented by other shape distributions on the image (↑↑↑: deflection on the upper side, ↓↓↓: deflection on the lower side) and color distribution ( The color type and the intensity thereof are changed corresponding to the direction and size of the deflection), or the deflection distribution can be represented more realistically and clearly as a three-dimensional image.

  The above-described inspection method and inspection apparatus according to the present invention provides information on the deflection of the entire wafer surface, that is, how the deflection on the upper side or the lower side is generated and distributed on the surface in a macro (relative manner). In addition, the absolute amount of the deflection can be obtained by the method described below.

(1) One pattern image is acquired as an image of the entire surface of the wafer by a line camera (image 1).
(2) A pattern for calculating the defocus amount is selected from the acquired image patterns (image 1). At this time, for example, a pattern area where a certain contrast difference is obtained is selected.
(3) The position of the line camera is changed, that is, for example, shifted upward by 200 μm, and an image at that position is acquired (image 2). Further, the image is shifted downward by 200 μm and an image at that position is acquired (image 3).
(4) In the obtained images 1, 2, and 3, the defocus amount (focus blur amount) in the pattern area selected in (2) is compared.
(5) From the result of (3) above, a calibration curve is calculated to determine how much the amount of blur in the selected pattern area differs when the height (position of the line camera, in other words, WD) differs by 200 μm. .
(6) By performing the above (5) at a plurality of locations within the wafer surface, the influence of defects (defocus, defects such as scratches caused by CMP) other than the deflection of the wafer is eliminated.

  The embodiment of the present invention has been described with reference to FIGS. However, the present invention is not limited to these embodiments. The present invention can be implemented in variously modified, modified, and modified embodiments based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

10 Stage 20 Substrate (wafer)
30 Linear motor 40 Controller 50, 50A, 50B, 50C Line camera 60 Distance variable mechanism 70 Line light source 80 Image processing apparatus (computer)
100 inspection equipment

Claims (5)

A line camera for inspecting the deflection of a substrate on which a circuit pattern is formed,
A line light source for irradiating light on the surface of the substrate;
A line sensor for receiving reflected light from a region including an edge of the circuit pattern on the surface of the substrate through a lens;
A line camera comprising: a distance variable mechanism capable of changing a distance between the surface of the substrate and the lens from a predetermined value around a maximum value of an expected deflection amount of the substrate. A line camera for inspecting the deflection of a substrate on which a circuit pattern is formed,
A line light source for irradiating light on the surface of the substrate;
A first line sensor that receives reflected light from a region including an edge of the circuit pattern on the surface of the substrate through a first lens;
A second line sensor adjacent to the first line sensor and receiving reflected light from the region of the surface of the substrate through a second lens;
The difference between the first distance between the surface of the substrate and the first lens and the second distance between the surface of the substrate and the second lens is the expected deflection of the substrate. A line camera that is set to a predetermined value around the maximum amount. A line camera for inspecting the deflection of a substrate on which a circuit pattern is formed,
A line light source for irradiating light on the surface of the substrate;
A first line sensor that receives reflected light from a region including an edge of the circuit pattern on the surface of the substrate through a first lens;
A second line sensor adjacent to the first line sensor and receiving reflected light from the region of the surface of the substrate through a second lens;
A third line sensor adjacent to the second line sensor and receiving reflected light from the region of the surface of the substrate through a third lens;
A first distance D1 between the surface of the substrate and the first lens; a second distance D2 between the surface of the substrate and the second lens; and a surface of the substrate and the third lens. The third distance D3 between the first lens and the third lens has a relationship of D1>D2> D3 or D1 <D2 <D3, and the difference between D1 and D3 is around the maximum value of the expected deflection of the substrate. There is a line camera. A line camera according to any one of claims 1 to 3,
A stage on which the substrate can be placed and moved in a horizontal / vertical direction;
A substrate deflection inspection apparatus comprising: a processing device that receives a signal from the line camera and calculates a deflection amount of the substrate. A method for inspecting the deflection of a substrate on which a circuit pattern is formed,
Irradiating the surface of the substrate with light;
Receiving reflected light from a region including an edge of the circuit pattern on the surface of the substrate through a lens, wherein a distance between the surface of the substrate and the lens is an expected amount of deflection of the substrate; Receiving reflected light from the region at at least two different distances varied around a maximum value of.