Measurement method and measuring apparatus

Abstract

To provide a measuring method and a measuring device, capable of accurately measuring a spacing between adjacent chips.SOLUTION: A measuring method includes: an adhering step 301 of adhering a wafer onto a surface of an expanded sheet attached to an annular frame; an expanding step 302 of expanding the expanded sheet onto which the wafer is adhered; a light application step 303 of applying light from one surface side of the wafer; an image generating step 304 of imaging the wafer through which the light is leaked along a scheduled dividing line from the other surface side of the wafer and generating an image; and a narrow spacing region identifying step 305 of identifying a region where a spacing between adjacent chips is narrow based on a threshold of brightness of a pixel between adjacent chips appearing in the image; and a spacing measuring step 307 of measuring the spacing of the identified region where a spacing between adjacent chips is narrow.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a measurement method and a measurement device for measuring the interval between adjacent chips of a wafer divided along a plurality of division planned lines formed in a grid pattern on the surface.

Background Art

[0002] When dividing a plate-like workpiece such as a wafer into a plurality of device chips, for example, a method is used in which a laser beam having a wavelength that penetrates the wafer is condensed on the division planned line to form a modified layer along the division planned line on the wafer (see, for example, Patent Document 1). Thereafter, by applying a force to the wafer from the outside, the wafer is divided into a plurality of device chips with the region corresponding to the modified and brittle division planned line as a boundary.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the force applied to the wafer from the outside is not necessarily constant in all regions within the wafer. Therefore, the intervals between adjacent chips after division are not constant either. If the intervals between adjacent chips are narrow, the device chips may come into contact with each other during conveyance to the next process, leading to damage.

[0005] Therefore, in a region where the intervals between adjacent chips are narrow, a method for accurately measuring the extent of the intervals and determining whether there are any problems even when transferred to the next process has been demanded. Thus, it has been demanded that the intervals between chips can be accurately measured.

[0006] The object of the present invention is to provide a measuring method and measuring apparatus that can measure the distance between adjacent chips. [Means for solving the problem]

[0007] To solve the above-mentioned problems and achieve the objective, the present invention provides a measurement method for measuring the spacing between adjacent chips obtained by dividing a wafer having grid-like division lines formed on its surface along the division lines, comprising: an attachment step of attaching the wafer to the surface of an expanded sheet mounted on an annular frame; an expansion step of expanding the expanded sheet to which the wafer is attached; a light irradiation step of irradiating light from one side of the wafer; an image generation step of imaging the wafer from the other side of the wafer along the division lines and generating an image; a narrow spacing region identification step of identifying a region where the spacing between adjacent chips is narrow based on a threshold of the brightness of pixels between adjacent chips shown in the image; and a spacing measurement step of measuring the spacing in the identified narrow spacing region of adjacent chips.

[0008] The present invention relates to a measuring device for measuring the spacing between adjacent chips obtained by dividing a wafer having grid-like division lines formed on its surface along the division lines, comprising: a holding table for holding a wafer unit integrated with an annular frame via an expanded sheet to which the wafer divided along the division lines is attached; a light source for irradiating light onto one side of the wafer unit held on the holding table; a first camera for imaging the other side of the wafer unit held on the holding table and generating an image; a second camera for measuring the spacing between adjacent chips in the wafer unit held on the holding table; and a control unit, wherein the control unit comprises: a narrow spacing region identification unit for identifying a region where the spacing between adjacent chips is narrow based on a brightness threshold of pixels between adjacent chips captured in the image; and a camera control unit for controlling the second camera to measure the spacing in the region where the spacing between adjacent chips is narrow identified by the narrow spacing region identification unit. [Effects of the Invention]

[0009] This invention has the effect of being able to measure the distance between adjacent chips. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic perspective view showing the configuration of the measuring device according to Embodiment 1. [Figure 2] Figure 2 is a schematic perspective view showing the measuring device and the dividing device that make up the divided measuring device shown in Figure 1. [Figure 3] Figure 3 is a schematic perspective view showing an example of a wafer to be processed by a splitting and measuring apparatus, which consists of the measuring apparatus shown in Figure 1 and the splitting apparatus shown in Figure 2. [Figure 4] Figure 4 is a flowchart showing the flow of the measurement method according to Embodiment 1. [Figure 5] Figure 5 is a schematic side view showing an extended step of the measurement method shown in Figure 4 in a partial cross-section. [Figure 6] Figure 6 is a schematic side view showing a partial cross-section of the light irradiation step of the measurement method shown in Figure 4. [Figure 7] Figure 7 is a schematic diagram illustrating an example of an image acquired by the first camera during the image generation step of the measurement method shown in Figure 4. [Figure 8] Figure 8 is a schematic side view showing a partial cross-section of the interval measurement step of the measurement method shown in Figure 4. [Figure 9] Figure 9 shows an example of a portion of the images acquired by the second camera during the interval measurement step of the measurement method shown in Figure 4. [Modes for carrying out the invention]

[0011] Embodiments for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiments. Furthermore, the components described below include those that can be easily imagined by those skilled in the art, and those that are substantially the same. In addition, the components described below can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the present invention.

[0012] [Embodiment 1] A measuring device according to Embodiment 1 of the present invention will be described based on the drawings. Figure 1 is a schematic perspective view showing the configuration of the measuring device according to Embodiment 1. Figure 2 is a schematic perspective view showing the dividing device that constitutes the measuring device and dividing measuring device shown in Figure 1. Figure 3 is a schematic perspective view showing an example of a wafer to be processed by a dividing measuring device composed of the measuring device shown in Figure 1 and the dividing device shown in Figure 2.

[0013] (wafer) The measuring device 1 shown in Figure 1 according to Embodiment 1 constitutes a divided measuring device 30 together with the dividing device 20 shown in Figure 2. The divided measuring device 30 is a device that divides the wafer 200 shown in Figure 3 into individual chips 210 and measures the spacing between the chips 210. The wafer 200 shown in Figure 3, which is the target of processing by the divided measuring device 30, is a disc-shaped semiconductor wafer or optical device wafer, etc., with a substrate of silicon, sapphire, gallium arsenide, or SiC (silicon carbide). As shown in Figure 3, the wafer 200 has devices 203 formed in each region partitioned by a plurality of division lines 202 formed in a grid pattern on the surface 201.

[0014] Device 203 is, for example, an integrated circuit such as an IC (Integrated Circuit) or LSI (Large Scale Integration), an image sensor such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor), or various types of memory (semiconductor memory devices).

[0015] The wafer 200 is irradiated with a laser beam having a wavelength that is transmissive to the substrate from the back surface 204 side on the back side of the front surface 201 along the division planned line 202, and a modified layer 205 (shown by a dotted line in FIG. 1) that is a division starting point is formed along the division planned line 202 inside the substrate. The wafer 200 is divided into individual chips 210 starting from the modified layer 205. Each chip 210 includes a part of the substrate divided along the division planned line 202 and a device 203 formed on the front surface of the substrate, and a part of the adhesive film 208 divided on the back surface 204 of the substrate is attached thereto.

[0016] The modified layer 205 means a region in which the density, refractive index, mechanical strength, and other physical properties are in a state different from those of the surroundings, and examples thereof include a melting treatment region, a crack region, an insulation breakdown region, a refractive index change region, and a region in which these regions are mixed.

[0017] After the modified layer 205 is formed inside the substrate along the division planned line 202, an adhesive film 208 attached to an expand sheet 207 to which an annular frame 206 is attached at the outer edge is attached to the back surface 204 of the wafer 200, and the wafer 200 is supported inside the opening inside the frame 206 by the expand sheet 207, thereby constituting a wafer unit 209. That is, the wafer unit 209 is integrally formed with the annular frame 206 via the expand sheet 207 to which the wafer 200 is attached, and includes the wafer 200, the adhesive film 208, the frame 206, and the expand sheet 207.

[0018] After the wafer 200 is supported inside the opening inside the frame 206 by the expand sheet 207, the region between the outer edge of the wafer 200 and the inner edge of the frame 206 of the expand sheet 207 is expanded, etc., and the wafer 200 is divided into individual chips 210 along the division planned line 202 starting from the modified layer 205. Also, when the wafer 200 is divided into individual chips 210, the adhesive film 208 is divided for each chip 210.

[0019] The adhesive film 208 is a die-attach film used for die bonding to fix individually divided chips 210 to other chips or substrates. The adhesive film 208 is formed in a disc shape with a diameter larger than the diameter of the wafer 200.

[0020] The expanded sheet 207 is made of a resin that is stretchable and shrinkable when heated. The expanded sheet 207 is formed in the shape of a disc with a diameter larger than the diameter of the wafer 200 and the adhesive film 208, and comprises a base layer made of a synthetic resin that is stretchable and shrinkable, and an adhesive layer made of a synthetic resin that is laminated on the base layer and attached to the wafer 200. The surface of the adhesive layer is the surface to which the adhesive film 208 is attached, and the back surface 204 of the wafer 200 is attached via the adhesive film 208.

[0021] In Embodiment 1, the expanded sheet 207 has an adhesive film 208 pre-attached to the surface to be attached, and is attached to the back surface 204 of the wafer 200 via the adhesive film 208, thus being a so-called 2-in-1 tape.

[0022] The frame 206 is formed in an annular shape with an inner diameter larger than the diameter of the wafer 200 and the adhesive film 208, and the outer edge of the expanded sheet 207 is attached to it.

[0023] (Divided measurement device) Next, the division and measurement device 30 will be described. The division and measurement device 30 comprises a division device 20 shown in Figure 2, a measurement device 1 shown in Figure 1, and a transport device (not shown). The division device 20 is a device that expands an expanded sheet 207 attached to the back surface 204 of the wafer 200 via an adhesive film 208 to divide the wafer 200 into individual chips 210 along the division line 202, and also divides the adhesive film 208 for each individual chip 210.

[0024] (splitting device) Next, the splitting device 20 will be described. As shown in Figure 2, the splitting device 20 comprises a frame holding unit 21, an expansion unit 24, and a heat shrinking unit (not shown). The frame holding unit 21 holds a frame 206 in which the wafer 200 is supported within an inner opening, and comprises a frame mounting plate 22 and a frame holding plate 23.

[0025] The frame mounting plate 22 has a circular opening 221 in its planar shape, and its upper surface 222 is formed in an annular shape, flat and parallel to the horizontal direction. In Embodiment 1, the inner diameter of the opening 221 of the frame mounting plate 22 is equal to the inner diameter of the frame 206. The frame 206 is placed on the upper surface 222 of the frame mounting plate 22 with the wafer 200 positioned on the opening 221. In Embodiment 1, the frame mounting plate 22 is provided to be vertically movable by a cylinder (not shown).

[0026] The frame retaining plate 23 is fixed above the frame mounting plate 22. The frame retaining plate 23 is formed in an annular shape with a circular opening 231 in the center that is the same size as the opening 221. The opening 231 of the frame retaining plate 23 is arranged coaxially with the opening 221 of the frame mounting plate 22. In Embodiment 1, the outer diameter of the frame retaining plate 23 is larger than the outer diameter of the frame mounting plate 22.

[0027] The frame holding unit 21 receives the wafer unit 209 by a transport device (not shown) onto the upper surface 222 of the lowered frame mounting plate 22, and the frame 206 of the wafer unit 209 is placed on the upper surface 222 of the frame mounting plate 22. The frame holding unit 21 raises the frame mounting plate 22 and holds the frame 206 of the wafer unit 209 by sandwiching it between the frame retaining plate 23 and the raised frame mounting plate 22.

[0028] The expansion unit 24 expands the expand sheet 207 by pressing the area of ​​the expand sheet 207 between the inner edge of the frame 206 held by the frame holding unit 21 and the outer edge of the wafer 200. As shown in Figure 2, the expansion unit 24 includes a support plate 25, a plurality of rollers 26, a holding table 27, and a lifting unit (not shown).

[0029] The support plate 25 is formed in a disc shape with an outer diameter smaller than the inner diameters of the frame mounting plate 22 and the frame retaining plate 23, and larger than the outer diameters of the wafer 200 and the adhesive film 208. The support plate 25 is positioned coaxially with the frame mounting plate 22 and the frame retaining plate 23 of the frame holding unit 21, that is, on the inner circumference side of the frame mounting plate 22 and the frame retaining plate 23 of the frame holding unit 21. In Embodiment 1, the upper surface 251 of the support plate 25 is formed flat along the horizontal direction.

[0030] The rollers 26 are formed in a cylindrical shape with a constant outer diameter and are supported on the outer edge of the upper surface 251 of the support plate 25 so as to be rotatable around their axis. In Embodiment 1, the multiple rollers 26 have the same outer diameter. The multiple rollers 26 are arranged at equal intervals in the circumferential direction on the outer edge of the upper surface 251 of the support plate 25, and their axes are arranged parallel to the tangent to the outer edge of the support plate 25. The multiple rollers 26 are positioned to overlap vertically with the aforementioned area of ​​the expanded sheet 207 of the wafer unit 209 held by the frame holding unit 21.

[0031] The lifting unit raises and lowers the support plate 25 along the vertical direction. In Embodiment 1, the lifting unit is a cylinder equipped with a rod that is parallel to and extends along the vertical direction. In Embodiment 1, the central part of the support plate 25 is attached to the tip of the rod. The lifting unit raises and lowers the support plate 25 and the roller 26 along the vertical direction by extending and retracting the rod.

[0032] In Embodiment 1, the lifting unit moves the support plate 25 and the roller 26 vertically between a position where the upper end of the roller 26 is on the same plane as the upper surface 112 of the frame mounting plate 22 of the frame holding unit 21 when it is raised, and a position where the upper end of the roller 26 is raised and positioned above the upper surface 112 of the frame mounting plate 22 of the frame holding unit 21 when it is holding the frame 206.

[0033] In Embodiment 1, when the support plate 25 and roller 26 are raised by the lifting unit, the upper end of the roller 26 is positioned above the upper surface 112 of the frame mounting plate 22 of the frame holding unit 21 that fixes the frame 206. As a result, the roller 26 contacts the area between the inner edge of the frame 206 and the outer edge of the wafer 200 of the expanded sheet 207 attached to the frame 206 fixed by the frame holding unit 21, and presses this area upward, thereby expanding the expanded sheet 207.

[0034] The holding table 27 is formed in a disc shape with an outer diameter smaller than the outer diameter of the support plate 25 and is arranged coaxially with the support plate 25. The holding table 27 is fixed to the upper surface 251 of the support plate 25 and has a holding surface 271 that suction-holds the wafer 200 of the wafer unit 209 via the expanded sheet 207. The holding table 27 is disc-shaped with a diameter smaller than the inner diameter of the frame 206, and the holding surface 271 is formed flat along the horizontal direction.

[0035] The holding table 27 has a holding surface 271 made of a porous material such as porous ceramic and is connected to a suction source (not shown). The holding surface 271 of the holding table 27 is located on the same plane as the upper end of a roller 26 that is rotatably supported on the outer edge of the upper surface 251 of the support plate 25.

[0036] The holding table 27 has the back surface 204 side of the wafer 200 placed on its holding surface 271 via the expanded sheet 207 of the wafer unit 209. The holding table 27 can hold the back surface 204 side of the wafer 200 by suction, as the holding surface 271 is sucked by a suction source.

[0037] The heat shrinking unit heats the aforementioned area of ​​the expanded sheet 207 expanded by the expansion unit 24 to shrink the slack that has formed in this area.

[0038] (Measuring device) Next, the measuring device 1 will be described. The measuring device 1 is a device that measures the distance between adjacent chips 210 obtained by dividing a wafer 200, on which a grid-like division line 202 is formed on the surface 201, along the division line 202 using a division device 20.

[0039] As shown in Figure 1, the measuring device 1 includes a holding table 10, a table moving unit (not shown), a light source 14, a first camera 15, a second camera 16, a camera lifting unit 17, and a control unit 18.

[0040] The holding table 10 holds a wafer unit 209, which is integrated with an annular frame 206, via an expanded sheet 207 to which wafers 200 divided along the division line 202 are attached. The holding table 10 comprises a frame 11, a transparent body 12, and positioning pins 13.

[0041] The frame 11 is formed in a frame shape with a circular opening 111 in its planar shape and a top surface 112 that is flat and parallel to the horizontal direction. In Embodiment 1, the inner diameter of the opening 111 of the frame 11 is smaller than the outer diameter of the frame 206 and larger than the inner diameter of the frame 206. The frame 11 is placed on the top surface 112 of the frame 206 with the wafer 200 positioned on the opening 111.

[0042] The transparent body 12 is made of a transparent material such as glass and is formed in a disc shape with an outer diameter equal to the inner diameter of the frame 11. The transparent body 12 is attached to the frame 11 by being fitted into the opening 111, and its upper surface 121 is formed flat along the horizontal direction and is located on the same plane as the upper surface 112 of the frame 11. In Embodiment 1, the thickness of the transparent body 12 is equal to the thickness of the frame 11. The wafer 200 of the wafer unit 209 is placed on the upper surface 121 of the transparent body 12 via the expanded sheet 207.

[0043] The positioning pins 13 are formed convexly from the upper surface 112 of the frame 11 and are arranged in multiples at intervals in the circumferential direction of the opening 111. The positioning pins 13 abut against the outer edge of the frame 206 placed on the upper surface 112, positioning the frame 206 in a position coaxial with the frame 11 and the transparent body 12.

[0044] In the holding table 10, the frame 206 is placed on the upper surface 112 of the frame 11 via the expandable sheet 207, and the wafer 200 is placed on the upper surface 121 of the transparent body 12 via the expandable sheet 207. Positioning pins 13 position the frame 206 and hold the wafer unit 209. In Embodiment 1, the back surface 204 of the wafer 200 is placed on the upper surface 121 of the transparent body 12 via the expandable sheet 207, but in the present invention, the front surface 201 of the wafer 200 may be placed on the upper surface 121 of the transparent body 12.

[0045] The table movement unit moves the holding table 10 along the X-axis direction, which is parallel to the horizontal direction, so that it passes between the light source 14 and the first camera 15.

[0046] The light source 14 irradiates light 141 onto one side of the wafer unit 209 held on the holding table 10, namely the back surface 204. The light source 14 is positioned below the holding table 27, which is positioned between the holding table 27 and the first camera 15 by a table movement unit. In Embodiment 1, the light source 14 consists of multiple light-emitting elements such as LEDs (Light Emitting Diodes) arranged along a straight line parallel to the Y-axis direction, perpendicular to the X-axis direction. In Embodiment 1, the light source 14 irradiates light 141 onto the wafer 200 of the wafer unit 209 as it passes between the light source 14 and the first camera 15, over the entire length of the wafer 200 in the Y-axis direction.

[0047] The first camera 15 captures the other side of the wafer unit 209 held on the holding table 10, which is the surface 201, and generates an image. The first camera 15 is positioned above the holding table 10, which is positioned between the holding table 10 and the light source 14 by a table moving unit. In Embodiment 1, the first camera 15 is a line sensor in which an image sensor such as a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary MOS) image sensor is arranged on a straight line parallel to the Y-axis direction.

[0048] The first camera 15 images the surface 201 of the wafer 200 of the wafer unit 209 as it moves along the X-axis direction by the table movement unit and passes between it and the light source 14, and outputs the image acquired to the control unit 18. In Embodiment 1, the image acquired by the first camera 15 is a grayscale image in which the brightness of each pixel is defined by multiple levels of gradation (for example, 256 levels). In Embodiment 1, the first camera 15 also images the entire surface 201 of the wafer 200 of the wafer unit 209 as it moves along the X-axis direction by the table movement unit, acquires an image including the entire surface 201 of the wafer 200, and outputs it to the control unit 18.

[0049] The second camera 16 measures the spacing between adjacent chips 210 in the wafer unit 209 held on the holding table 10. The second camera 16 is attached to the first camera 15 and positioned above the holding table 10, which is positioned between the holding table 10 and the light source 14 by a table moving unit. The second camera 16 is also provided to be movable in the Y-axis direction relative to the first camera 15 by a camera moving unit (not shown).

[0050] In Embodiment 1, the second camera 16 is a two-dimensional sensor in which an image sensor, such as a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary MOS) image sensor, is arranged on a straight line parallel to both the X-axis and Y-axis directions. The second camera 16 is positioned above any position on the surface 201 of the wafer 200 of the wafer unit 209 held on the holding table 10 by a table moving unit and a camera moving unit, and images the arbitrary position on the surface 201 of the wafer 200, and outputs the image acquired to the control unit 18. In Embodiment 1, the image acquired by the second camera 16 is a grayscale image in which the brightness of each pixel is defined by multiple levels of gradation (for example, 256 levels). The second camera 16 measures the distance between chips 210 at an arbitrary position on the surface 201 of the wafer 200 by imaging that arbitrary position.

[0051] The camera lifting unit 17 moves the first camera 15 along the Z-axis, which is perpendicular to both the X-axis and Y-axis, thereby raising and lowering the first camera 15 and the second camera 16.

[0052] The control unit 18 controls the above-described components of the measuring device 1 to cause the measuring device 1 to perform a measurement operation of the spacing between the chips 210 on the wafer 200. In the first embodiment, the control unit 18 also controls the above-described components of the splitting measuring device 30 to cause the splitting measuring device 30 to perform a processing operation of splitting the wafer 200 into individual chips 210.

[0053] The control unit 18 is a computer comprising an arithmetic processing unit having a microprocessor such as a CPU (central processing unit), a storage device having memory such as ROM (read-only memory) or RAM (random access memory), and an input / output interface device. The arithmetic processing unit of the control unit 18 performs arithmetic processing according to the computer program stored in the storage device and outputs control signals for controlling the segmented measurement device 30 to the aforementioned components of the segmented measurement device 30 via the input / output interface device.

[0054] The control unit 18 is connected to a display unit (not shown) which consists of a liquid crystal display device that displays the status of machining operations and images, and an input unit (not shown) which is used by the operator to register machining conditions, etc. The input unit consists of at least one of a touch panel provided on the display unit and an external input device such as a keyboard.

[0055] Furthermore, the control unit 18 includes a measurement operation control unit 181, a narrow spacing area identification unit 182, a camera control unit 183, a spacing data storage unit 184, and a spacing measurement unit 185. The measurement operation control unit 181 controls each of the above-mentioned components of the measuring device 1 to cause the measuring device 1 to perform a measurement operation of the spacing between the chips 210 on the wafer 200, and also controls each of the above-mentioned components of the splitting measuring device 30 to cause the splitting measuring device 30 to perform a processing operation to split the wafer 200 into individual chips 210.

[0056] The narrow-interval region identification unit 182 identifies regions where the spacing between adjacent chips 210 is narrow based on a threshold of the brightness of pixels between adjacent chips 210 in the image captured and acquired by the first camera 15. In Embodiment 1, the narrow-interval region identification unit 182 extracts pixels that have captured the division line 202 of the image captured and acquired by the first camera 15, and determines whether the brightness of each extracted pixel is greater than or equal to a predetermined value. In Embodiment 1, the narrow-interval region identification unit 182 identifies the location on the wafer 200 where the pixels whose brightness is determined to be less than a predetermined value have captured the image as regions where the spacing between chips 210 on the wafer 200 is narrow.

[0057] The camera control unit 183 controls the second camera 16 to measure the spacing between adjacent chips 210 in a region where the spacing between them is narrow, as identified by the narrow-spacing region identification unit 182. In Embodiment 1, the camera control unit 183 controls the table movement unit and the camera movement unit to position the second camera 16 above the region where the spacing between chips 210 of the wafer 200 is narrow, as identified by the narrow-spacing region identification unit 182, and causes the second camera 16 to image the region where the spacing between chips 210 of the wafer 200 is narrow, as identified by the narrow-spacing region identification unit 182.

[0058] The interval data storage unit 184 stores interval data that links the sum of the brightness of pixels aligned in the width direction of the division line 202 among the pixels that captured the division line 202 of the image captured by the second camera 16 with the interval between the chips 210.

[0059] The interval measurement unit 185 extracts pixels that capture the division line 202 of the image acquired by the second camera 16, and calculates the sum of the brightness of the pixels aligned in the width direction of the division line 202 of the extracted pixels. The interval measurement unit 185 calculates the width of each position in the longitudinal direction of the division line 202, i.e., the interval between chips 210, from the interval data and the sum of the brightness of the pixels aligned in the width direction of the division line 202.

[0060] The functions of the measurement operation control unit 181, the narrow interval area identification unit 182, the camera control unit 183, and the interval measurement unit 185 are realized by the aforementioned arithmetic processing unit performing calculations according to the computer program stored in the memory device. The function of the interval data storage unit 184 is realized by the aforementioned memory device.

[0061] (Conveyor device) Next, the transport device for the splitting and measuring device 30 will be described. The transport device consists of a cassette that houses at least one wafer unit 209 installed in the main body of the splitting and measuring device 30, and transports the wafer unit 209 between the splitting device 20 and the measuring device 1.

[0062] (Measurement method) Next, the measurement method according to Embodiment 1 will be described. Figure 4 is a flowchart showing the flow of the measurement method according to Embodiment 1. The measurement method according to Embodiment 1 is a method for measuring the distance between adjacent chips 210 obtained by dividing a wafer 200, on which grid-like division lines 202 are formed on the surface 201, along the division lines 202.

[0063] Furthermore, the measurement method according to Embodiment 1 is a method in which an expanded sheet 207 is attached to the back surface 204 of the wafer 200 via an adhesive film 208, the expanded sheet 207 is expanded to divide the wafer 200 into individual chips 210 along the planned division line 202, and the adhesive film 208 is divided for each individual chip 210. As shown in Figure 4, the measurement method according to Embodiment 1 comprises an attachment step 301, an expansion step 302, a light irradiation step 303, an image generation step 304, a narrow-interval region identification step 305, and an interval measurement step 307.

[0064] (Attachment step) The attachment step 301 is the step of attaching the wafer 200 to the surface of the expanded sheet 207 which is mounted on an annular frame 206. In Embodiment 1, as shown in Figure 3, in attachment step 301, the adhesive film 208 attached to the expanded sheet 207, to which the annular frame 206 is attached to the outer edge, is attached to the back surface 204 of the wafer 200, which has a modified layer 205 formed inside the substrate along the planned division line 202.

[0065] In Embodiment 1, in the attachment step 301, the back surface 204 of the wafer 200 is attached to the adhesive film 208 attached to the expanded sheet 207 to which the frame 206 is attached to the outer edge, thereby mounting the wafer 200 to the frame 206 via the expanded sheet 207.

[0066] (Extension step) Figure 5 is a schematic side view showing a partial cross-section of the expansion step of the measurement method shown in Figure 4. Expansion step 302 is the step of expanding the expanded sheet 207 to which the wafer 200 is attached.

[0067] In expansion step 302, the splitting measurement device 30 is equipped with a cassette containing the wafer 200, i.e., wafer unit 209, which has been attached to the expanded sheet 207 by the attachment step. Upon receiving an operation start instruction from an operator or the like, the transport device transports the wafer unit 209 from the cassette to the splitting device 20. In expansion step 302, the splitting device 20 lowers the support plate 25 of the expansion unit 40 and the frame mounting plate 22 of the frame holding unit 21, and the frame 206 of the wafer unit 209 is carried onto the upper surface 222 of the frame mounting plate 22 by the transport device.

[0068] In extension step 302, the splitting device 20 raises the frame mounting plate 22 and holds the frame 206 of the wafer unit 209 in the frame holding unit 21, as shown in Figure 2. In extension step 302, the splitting device 20 raises the support plate 25 and the holding table 27 in the lifting unit.

[0069] As shown in Figure 5, the upper end of the roller 26 comes into contact with the area of ​​the expanded sheet 207, and the upper end of the roller 26 presses the area of ​​the expanded sheet 207 from below upward, causing the expanded sheet 207 to expand in the planar direction. In expansion step 302, as a result of the expansion of the expanded sheet 207, tensile forces act radially on the expanded sheet 207.

[0070] When a radial tensile force is applied to the expanded sheet 207 attached to the back surface 204 of the wafer 200, the wafer 200 is divided into individual chips 210 along the planned division line 202, with the modified layer 205 forming along the planned division line 202, using the modified layer 205 as a starting point. In addition, the wafer 200 widens, creating gaps between the chips 210. Furthermore, when a radial tensile force is applied to the expanded sheet 207, the adhesive film 208 breaks along the modified layer 205, i.e., the planned division line 202, for each individual chip 210, and the pieces attached to adjacent chips 210 separate across the planned division line 202.

[0071] In extension step 302, the splitting device 20 holds the back surface 204 of the wafer 200 by suction to the holding surface 271 of the holding table 27 via the expanded sheet 207, lowers the support plate 25 and the holding table 27, and heats and shrinks the slack that has occurred in the aforementioned area of ​​the expanded sheet 207 with a heat shrink unit to maintain the spacing between the chips 210. In extension step 302, the splitting device 20 stops the suction holding of the wafer 200 on the holding surface 271 of the holding table 27, lowers the frame mounting plate 22, and the transport device transports the wafer unit 209, in which the wafer 200 has been split into individual chips 210, from the splitting device 20 to the measuring device 1.

[0072] (Light irradiation step) Figure 6 is a schematic side view showing a partial cross-section of the light irradiation step of the measurement method shown in Figure 4. Note that the adhesive film 208 is omitted in Figure 6. The light irradiation step 303 is a step in which light is irradiated from one side of the wafer 200, the back side 204. In Embodiment 1, in the light irradiation step 303, the measuring device 1 receives wafer units 209, in which the wafer 200 has been divided into individual chips 210 by the dividing device 20, onto the upper surfaces 112,121 of the holding table 10 via a transport device. In the light irradiation step 303, as shown in Figure 6, the measuring device 1 has a measurement operation control unit 181 that irradiates light 141 upward from a light source 14.

[0073] (Image generation step) Figure 7 is a schematic diagram showing an example of an image acquired by the first camera in the image generation step of the measurement method shown in Figure 4. The image generation step 304 is a step in which the surface 201 of the wafer 200 from which light 53 has leaked along the division line 202 is imaged from the other side of the wafer 200, the surface 201 side, and an image 400 (shown in Figure 7) is generated.

[0074] In Embodiment 1, during the image generation step 304, the measuring device 1 irradiates light 141 from the light source 14, and the measurement operation control unit 181 moves the holding table 27 in the X-axis direction using the table movement unit, while the first camera 15 images the surface 201 of the wafer 200 held on the holding table 27. As a result, the wafer 200 is divided along the planned division line 202 by the division device 20 in the expansion step 302, and the spacing between the chips 210 is maintained, so light 141 leaks from the planned division line 202 towards the surface 201.

[0075] In Embodiment 1, in the image generation step 304, the first camera 15 receives light 141 leaked from the division line 202 and images the surface 201 of the wafer 200. In Embodiment 1, in the image generation step 304, the control unit 18 acquires an image 400, shown as an example in Figure 7, from the first camera 15.

[0076] In Figure 7, an example image 400 shows that, among the pixels that imaged the contour of the wafer 200 and each planned division line 202 of the wafer 200, pixels with a brightness equal to or greater than a predetermined value are shown with a solid line 401, pixels with a brightness less than a predetermined value are shown with a dashed line 402, and other pixels are shown with a white background.

[0077] (Narrow-interval region identification step) The narrow-spaced region identification step 305 is a step in which a region 403 in which the spacing between adjacent chips 210 is narrow is identified based on a threshold of the brightness of pixels between adjacent chips 210 in the image 400. In Embodiment 1, in the narrow-spaced region identification step 305, the narrow-spaced region identification unit 182 extracts pixels that have captured the division line 202 of the image 400 acquired by the first camera 15, and determines whether the brightness of each extracted pixel is greater than or equal to a predetermined value. In Embodiment 1, in the narrow-spaced region identification step 305, the narrow-spaced region identification unit 182 identifies the position of the wafer 200 in which the pixels whose brightness is determined to be less than a predetermined value were captured as a region 403 in which the spacing between chips 210 of the wafer 200 is narrow. In the image 400 shown in Figure 7, the narrow-spaced region identification unit 182 identifies the position indicated by the dashed line 402 as a region 403 in which the spacing between chips 210 is narrow.

[0078] In Embodiment 1, in the narrow-interval region identification step 305, the narrow-interval region identification unit 182 determines whether or not a region 403 with narrow spacing between chips 210 is identified in the image 400 captured by the first camera 15, that is, whether or not there is a region 403 with narrow spacing between chips 210 in the image 400 (step 306). In Embodiment 1, in the narrow-interval region identification step 305, if the narrow-interval region identification unit 182 determines that a region 403 with narrow spacing between chips 210 is identified in the image 400 captured by the first camera 15, that is, if there is a region 403 with narrow spacing between chips 210 in the image 400 (step 306: Yes), the process proceeds to the spacing measurement step 307.

[0079] (Interval measurement step) Figure 8 is a schematic side view showing a partial cross-section of the interval measurement step of the measurement method shown in Figure 4. Figure 9 is a diagram showing an example of a part of the image acquired by the second camera during the interval measurement step of the measurement method shown in Figure 4. The interval measurement step 307 is a step to measure the interval between adjacent chips 210 in the region 403 where the interval between adjacent chips 210 is narrow, as identified in the narrow interval region identification step 305.

[0080] In Embodiment 1, during the spacing measurement step 307, the camera control unit 183 controls the table movement unit and the camera movement unit to sequentially position the second camera 16 above the region 403 where the spacing between the chips 210 of the wafer 200 is narrow, as identified by the narrow spacing region identification unit 182, as shown in Figure 8, and to sequentially image the region 403 where the spacing between the chips 210 of the wafer 200 is narrow, as identified by the narrow spacing region identification unit 182, with the second camera 16.

[0081] In Embodiment 1, in the interval measurement step 307, the interval measurement unit 185 extracts pixels 502 (shown as parallel diagonal lines in Figure 9) that have captured the division line 202 from the pixels 501 of the image 500 (a partial example is shown in Figure 9) captured and acquired by the second camera 16, and calculates the sum of the brightness of the extracted pixels 502 that are aligned in the width direction of the division line 202. In Embodiment 1, in the interval measurement step 307, the interval measurement unit 185 calculates the width of each position in the longitudinal direction of the division line 202, i.e., the interval between chips 210, from the interval data stored in the interval data storage unit 184 and the sum of the brightness of the pixels 502 aligned in the width direction of the division line 202.

[0082] In Embodiment 1, in the interval measurement step 307, the measurement device 1 terminates the measurement method when the control unit 18 stores the interval between chips 210 calculated by the interval measurement unit 185 and their positions on the wafer 200 in association. Also in Embodiment 1, in the narrow spacing region identification step 305, the narrow spacing region identification unit 182 determines that no region 403 with narrow spacing between chips 210 is identified in the image 400 captured by the first camera 15, that is, it determines that there is no region 403 with narrow spacing between chips 210 in the image 400 (step 306: No), and terminates the measurement method.

[0083] As described above, in the measurement device 1 and measurement method according to Embodiment 1, in the narrow-interval area identification step 305, the narrow-interval area identification unit 182 identifies a region 403 in the image 400 where the spacing between chips 210 is narrow, and in the spacing measurement step 307, the spacing measurement unit 185 uses the second camera 16 to capture an image 500 of the narrow region 403 identified in the narrow-interval area identification step 305, and measures the spacing between adjacent chips 210.

[0084] As a result, the measuring device 1 and measuring method according to Embodiment 1 have the effect of being able to measure the distance between adjacent chips 210 quickly and accurately. [Explanation of Symbols]

[0085] 1. Measuring device 10 Retention Table 14 Light source 15. First camera 16. Second Camera 18 Control Unit 141 light 182 Narrow interval area identification part 183 Camera Control Unit 200 wafers 201 Surface (the other side) 202 planned division lines 204 Reverse side (one side) 206 frames 207 Expandable Sheet 209 wafer units 210 chips 301 Adhesive Step 302 Extension Step 303 Light irradiation step 304 Image generation step 305 Step to identify narrow-interval region 307 Interval measurement step 400 images 403 Narrow area

Claims

1. A measurement method for measuring the distance between adjacent chips obtained by dividing a wafer, which has a grid-like division line formed on its surface, along the division line, The process includes a bonding step of attaching the wafer to the surface of an expanded sheet mounted on an annular frame, An expansion step of expanding the expanded sheet on which the wafer is attached, A light irradiation step in which light is shone from one side of the wafer, Image generation step: Image the wafer from which the light has leaked along the planned division line from the other side of the wafer, and generate an image. A narrow-spacing region identification step identifies a region where the spacing between adjacent chips is narrow based on a brightness threshold of pixels between adjacent chips in the image, Includes a spacing measurement step of measuring the spacing between identified adjacent chips in a region where the spacing is narrow. A measurement method characterized by the following features.

2. A measuring device for measuring the distance between adjacent chips obtained by dividing a wafer, which has a grid-like division line formed on its surface, along the division line, A holding table that holds a wafer unit integrated with an annular frame via an expanded sheet to which wafers divided along the planned division line are attached, A light source that illuminates one side of the wafer unit held on the holding table, A first camera that captures the other side of the wafer unit held on the holding table and generates an image, A second camera for measuring the distance between adjacent chips in a wafer unit held on the holding table, It has a control unit, The control unit is, A narrow-spacing region identification unit identifies a region where the spacing between adjacent chips is narrow based on a brightness threshold of pixels between adjacent chips in the image, The system includes a camera control unit that controls the second camera to measure the spacing in a region where the spacing between adjacent chips is narrow, as identified by the narrow spacing region identification unit. A measuring device characterized by the following features.

Images