Circuit board processing method

Abstract

To enable the position of a faulty point in a substrate to be identified even when inspecting the substrate from the reverse side.SOLUTION: Provided is a substrate processing method with which a substrate 10 where a pattern and a plurality of scheduled divide lines 110 are formed on the surface is processed along the scheduled divide lines 110. The substrate processing method comprises: a holding step for holding the surface of the substrate 10 with a holding table; a processing step for detecting the scheduled divide lines 110 on the surface from the surface side via the holding table, or from the reverse side by an infrared camera, and processing the substrate from a reverse side 12 by a processing unit along the scheduled divide lines 110; and an inspection step for placing, after the processing step, the substrate 10 on an inspection table and inspecting processing quality from the reverse side 12. In the inspection step, a faulty point 114 is stored in memory, with respect to a feature point such as a notch 13 that the substrate 10 has.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a method for dividing a substrate.

Background Art

[0002] In the process of dividing a substrate on which a device region formed by a plurality of planned division lines is formed on the surface, after processing, there is a step of placing the substrate on an inspection table and inspecting whether there are any defective portions. When performing inspection from the surface side of the substrate in this inspection step, the coordinate position of the defective chip on the substrate is memorized based on marks for alignment formed on the surface. However, when performing inspection from the back side, the reference marks on the surface cannot be seen. Therefore, when the inspection table is transparent, inspection is performed while imaging from the surface side through the inspection table, and when the inspection table is not transparent, inspection is performed while imaging the surface devices from the back side with an IR camera (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in an inspection unit that cannot image through an inspection table or an inspection unit not equipped with an IR camera, there is a problem that defective portions cannot be memorized in association with the marks on the surface. Therefore, even if defective portions can be specified in the inspection device, when the substrate is transported to another process, the defective portions become unknown due to transport misalignment, and there is a problem of misidentifying the defective portions. This invention has been made in view of such problems, and aims to enable the storage of the location of defective areas within the substrate even when inspecting the substrate from the back side, so that the defective areas can be identified in a later process. [Means for solving the problem]

[0005] The present invention relates to a method for processing a substrate in which a pattern and a plurality of division lines are formed on the surface, along the division lines, comprising: a holding step of holding the surface of the substrate on a holding table; a processing step of detecting the division lines on the surface from the surface side via the holding table or from the back side using an infrared camera, and processing the substrate from the back side along the division lines using a processing unit. Alignment formed on the surface Using the mark as a reference, the processing unit forms an inspection mark on the back surface. A mark formation step, The processing step and the step of forming the inspection mark The inspection step includes, after which the substrate is placed on an inspection table and the processing quality is inspected from the back side, and in the inspection step, The inspection mark It is characterized by storing defective parts in a standard. The processing step and the inspection mark forming step involve forming either a dividing groove that divides the substrate, a processing groove that does not divide the substrate, or a modified layer formed inside the substrate. If the processing step includes a protective film forming step of forming a protective film on the back surface of the substrate, an exposure step of removing the protective film formed on the division line using the processing unit after the protective film forming step to expose the division line, and an etching step of performing plasma etching from the back surface after the exposure step to process the substrate along the division line, then it is desirable that the inspection mark forming step removes the protective film in the shape of the inspection mark at an arbitrary position using the processing unit, and forms the inspection mark on the back surface of the substrate in the etching step. Prior to the processing step, the process includes a protective member forming step in which a first protective member is formed on the surface. The inspection step may be followed by a transfer step in which a second protective member is formed on the back surface and the first protective member is peeled off from the front surface. [Effects of the Invention]

[0006] In this invention, in an inspection step where the processing quality is inspected from the back side, defective areas are stored based on characteristic points on the substrate. Unlike the front side, the back side does not have alignment marks or other patterns that serve as a reference for identifying the location of defective areas. However, by storing the location of defective areas based on characteristic points on the substrate, the location of defective areas can be linked to characteristic points on the substrate and stored without imaging the front side. Therefore, in other processes as well, defective areas can be identified based on the characteristic points on the substrate. By using notches, orientation flats, or the center point of the substrate as feature points, it is possible to utilize feature points already formed on the semiconductor wafer, thus eliminating the need to create feature points for inspection purposes. Furthermore, by forming inspection marks on the back surface based on alignment marks on the front surface, defective areas can be memorized based on the inspection marks on the back surface without viewing the image on the front surface, and defective areas can be identified in other processes based on the inspection marks. The processing steps consist of a protective film formation step, an exposure step, and an etching step. In the inspection mark formation step, the protective film is removed in the shape of the inspection mark, and in the etching step, the inspection mark is formed. This allows for simultaneous processing along the planned division line and formation of the inspection mark in the etching step. If the process includes a protective member forming step in which a first protective member is formed on the surface before the processing step, and a transfer step in which a second protective member is formed on the back surface and the first protective member is peeled off from the surface after the inspection step, even if the inspection step is performed from the back side, it is necessary to identify the defective area from the front side. However, by identifying the defective area based on characteristic points, it is possible to recognize the defective area even from the surface. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view showing an example of a circuit board. [Figure 2] It is a cross-sectional view showing the state where the substrate is held by the holding table. [Figure 3] It is a perspective view showing the state where the first protective member is adhered to the surface of the substrate and supported by the frame. [Figure 4] It is a schematic cross-sectional view showing an example of a processing step using a laser processing apparatus. [Figure 5] It is a perspective view showing an example of the divided substrate. [Figure 6] It is a schematic cross-sectional view showing the state where the substrate is held by a holding table made of a transparent body, and the planned division line is detected and processed from below the transparent body. [Figure 7] It is a schematic cross-sectional view showing an example of an inspection step of performing inspection from the back side. [Figure 8] It is a plan view showing an example of a defective device. [Figure 9] It is a schematic cross-sectional view showing the state of adhering the second protective member in the transfer step. [Figure 10] It is a schematic cross-sectional view showing the state of peeling off the first protective member in the transfer step. [Figure 11] It is a plan view showing the front side of the substrate after the transfer step is performed. [Figure 12] It is a plan view showing an example of a substrate having inspection marks formed on the back surface. [Figure 13] It is a plan view showing an example of a substrate having alignment marks formed on the surface. [Figure 14] It is a schematic cross-sectional view showing an example of a processing step using a cutting device. [Figure 15] It is a schematic cross-sectional view showing the state of forming a protective film on the back surface of the substrate. ]> [Figure 16] It is a schematic cross-sectional view showing the state of removing the protective film to expose the planned division line. [Figure 17] It is a schematic cross-sectional view showing an example of a processing step of dividing the substrate by plasma etching. [Figure 18] It is a schematic cross-sectional view showing the state of removing the protective film. [Figure 19]It is a plan view showing a state where a removal part corresponding to an inspection mark is formed on a protective film. [Figure 20] It is a plan view showing a wafer on which an orientation flat is formed. [Figure 21] It is a plan view showing the center of a substrate on which a notch is formed. [Figure 22] It is a plan view showing a process of obtaining the center of a substrate on which a notch is formed. [Figure 23] It is a plan view showing the center of a substrate on which an orientation flat is formed. [Figure 24] It is a plan view showing a process of obtaining the center of a substrate on which an orientation flat is formed. [Figure 25] It is a schematic cross-sectional view showing a state of grinding the back surface of a substrate.

Embodiments for Carrying Out the Invention

[0008] 1 First Embodiment (1-1) Protective Member Forming Step As shown in FIG. 1, the surface 11 of the substrate 10 is adhered to the adhesive surface 21 of the first protective member 20. Here, a device 111 having a circuit pattern is formed in a region partitioned by a division planned line 110 on the surface 11 of the substrate 10, and the first protective member 20 serves to protect the device 111. A notch 13 indicating the direction of the crystal orientation is formed at the peripheral portion of the substrate 10.

[0009] (1-2) Holding Step As shown in FIG. 2, the substrate 10 is sucked and held by the holding table 31 of the laser processing apparatus 30 on the surface 11 side via the first protective member 20, and the back surface 12 is in a state of being exposed upward.

[0010] Alternatively, instead of attaching the first protective member 20, a resin sheet without an adhesive layer may be pressed onto the substrate, or a rigid support substrate may be attached via wax or resin. Furthermore, as shown in Figure 3, the substrate 10 may be supported by the frame 23 via the first protective member 20 by attaching a first protective member 20 with a larger diameter than the substrate 10 to the surface 11 of the substrate 10, and attaching the lower surface 231 of the ring-shaped frame 23 to the outer circumference of the adhesive surface 21 of the first protective member 20. The following describes the processing of the substrate 10 supported by the frame 23 via the first protective member 20.

[0011] (1-3) Machining Steps As shown in Figure 4, the laser processing apparatus 30 is equipped with a laser irradiation head 32 and an infrared camera 33 in addition to the holding table 31 shown in Figure 2. In this step, the holding table 31 is moved in the X-axis direction, and the surface 11 is imaged via the back surface 12 using the infrared camera 33 to detect the division line 110 shown in Figure 3. Then, the laser irradiation head 32 irradiates the detected division line 110 with laser light 320 of a wavelength absorbed by the substrate 10, and the laser irradiation head 32 and the holding table 31 are moved relative to each other in the X-axis direction to perform ablation processing along the division line 110, forming a division groove 112 that penetrates both the front and back surfaces of the substrate 10. Then, the laser irradiation head 32 is moved in the Y-axis direction indicated by the arrow 310 by the distance of the adjacent division line 110, and the same processing is performed. Once the division groove 112 is formed along all the division lines 110 in the same direction, the holding table 31 is rotated 90 degrees and the same ablation processing is performed. As a result, as shown in Figure 5, the substrate 10 is divided vertically and horizontally into chips 113 for each device 111. Alternatively, instead of the dividing grooves 112, processing grooves that do not penetrate the front and back surfaces and do not divide the substrate 10 may be formed, and then the substrate may be divided into chips 113 by applying external force.

[0012] As shown in Figure 6, the surface 11 side of the substrate 10 may be held by a transparent holding table 34. In this case, the planned division lines can be detected by placing the imaging unit 35 below the holding table 34 and imaging the surface 11. Therefore, an infrared camera is not required in this case.

[0013] In the processing step, a laser processing device 30 may be used to irradiate the substrate 10 with laser light of a wavelength that is transparent to the substrate 10, while moving the laser irradiation head 32 and the holding table 31 relative to each other in the horizontal direction, thereby forming a modified layer that will serve as the starting point for division along the planned division lines 110 inside the substrate 10. In this case as well, a modified layer is formed inside the substrate 10 along all of the planned division lines 110. Once a modified layer has been formed inside in this way, the substrate is later divided into individual device chips starting from the modified layer by grinding the back surface 17 to expose the modified layer or by applying external force to the modified layer.

[0014] (1-4) Examination Steps As shown in Figure 7, the inspection device 40 includes an inspection table 41 on which the substrate 10 divided into chips 113 is placed, and an imaging unit 42 that images the substrate 10 placed on the inspection table 41 from above. The side of the substrate 10 with the first protective member 20 attached to the surface 11 is placed on the inspection table 41.

[0015] In this step, the inspection table 41 and the imaging unit 42 are moved relative to each other in the horizontal direction of the arrow 410, while imaging the chips 113 from above to detect defects such as chipping, cracks, chips, and holes. During this relative movement, multiple rows of chips 113 can be imaged simultaneously. By performing this relative movement back and forth multiple times, all chips 113 are imaged, and an image of all chips 113 is formed.

[0016] Then, the processing quality is inspected based on the image, and if a defective device is detected, its location is stored in a memory unit (not shown). This location is stored based on characteristic points of the substrate. For example, the location of the defective device 114 shown in Figure 8 is stored based on the notch 13 formed on the substrate 10. For example, if the direction of the perpendicular line from the notch 13 to the center of the substrate 10 is the Y direction, and the direction perpendicular to the Y direction is the X direction, then the defective device 114 is located four device units in the -X direction from the notch 13 and eight device units in the +Y direction from the notch 13. Therefore, in this case, the location of the defective device 114 is stored in the memory unit as, for example, (-4, 8). Note that the inspection method is not limited to this, and can be changed as appropriate, such as by inspecting electrical characteristics with a probe.

[0017] (1-5) Transfer Step When picking up individual chips 113 formed by dividing the substrate 10 in the processing step in the next process, the chips are held in the pickup device with the surface side facing upwards in order to attract the surface side of the chip. Therefore, it is necessary to peel off the first protective member 20 before pickup. Similarly, if any processing is to be performed on the surface side, it is also necessary to peel off the first protective member 20. Therefore, using the transfer device 50 shown in Figure 9, the second protective member 25 is attached to the back surface 12 of the substrate 10, which has been divided into chips 113 and maintains its original shape as a whole, and then the first protective member 20 is peeled off.

[0018] For example, the divided substrate 10 is held on the table 51 of the transfer apparatus 50 shown in Figure 9 with the first protective member 20 facing downwards. Then, the second protective member 25 is attached to the upper surface 232 of one end of the frame 23, and the second protective member 25 is attached to the back surface 116 of the chip 113 while rolling the roller 52. When the second protective member 25 is attached to the upper surface 232 of the other end of the frame 23, the attachment is completed.

[0019] Subsequently, as shown in Figure 10, the second protective member 25 is held on the table 51, the end of the first protective member 20 is lifted, and that end is pulled toward the other end, thereby peeling off the first protective member 20. In this way, the surface 115 of each chip 113 is exposed.

[0020] Even after the first protective member 20 is peeled off the surface 115 and the second protective member 25 is attached to the back surface 116, the position of the defective device 114 can still be recognized as a position (4, 8) relative to the notch 13, as shown in Figure 11, similar to Figure 8. Note that because the front and back surfaces of the substrate 10 have been reversed, the positive and negative signs of the position in the X direction are reversed compared to before transfer shown in Figure 8.

[0021] The chip 113, thus divided and with its surface 115 side exposed, is transported to a pickup device while attached to the second protective member 25, or to a processing device that performs surface treatment. For example, the pickup device receives location information (4, 8) of the defective device 114 from the inspection device 40. Based on this location information, the pickup device can then perform processing such as excluding the defective device 114 from the pickup target. Therefore, even if the circuit board rotates and its center position shifts when it is transported to the holding table of the pickup device, the defective area can be accurately identified based on the notches, which are characteristic points of the circuit board.

[0022] 2. Second Embodiment (2-1) Protective member formation step This step may be the same as in Figure 2 of the first embodiment, but here, as shown in Figures 12 and 13, a first protective member 20 with a larger diameter than the substrate 15 is attached to the surface 16 of the substrate 15, and a ring-shaped frame 23 is attached to the outer circumference of the adhesive surface 21 of the first protective member 20, so that the substrate 15 is supported by the frame 23 via the first protective member 20. Here, as shown in Figure 13, a device 166 is formed on the surface 16 of the substrate 15 in an area demarcated by the division line 160, and the first protective member 20 plays a role in protecting the device 111.

[0023] (2-2) Holding step The holding step is carried out in the same manner as in the first embodiment, and the first protective member 20 is held on the holding table 31 of the laser processing apparatus 30, as shown in Figure 4.

[0024] (2-3) Machining Steps In the surface 16 of the substrate 15 shown in Figure 13, a first alignment mark 161 and a second alignment mark 162 are formed in areas where no devices are formed. The positional relationship between the first alignment mark 161 and the second alignment mark 162 and the division line 110 to be detected first is stored in advance in a storage unit (not shown). By detecting the first alignment mark 161 and the second alignment mark 162 of the substrate 15 held on the holding table 31 shown in Figure 4 via the first protective member 20 using an infrared camera 33, the position of the division line 110 to be processed can be identified, and the laser irradiation head 32 can be positioned above the division line 110. Note that the alignment marks, such as the first alignment mark 161 and the second alignment mark 162, are not patterns formed on each chip, but may be special marks formed for alignment, or the patterns of the devices formed on each chip may be used. When using the patterns of the devices formed on each chip, it is preferable to store them together with the rows and columns of the devices so that the position of the chips to be identified as defective chips does not shift.

[0025] Then, by moving the holding table 31 and the laser irradiation head 32 relative to each other in the horizontal direction, dividing grooves or modified layers are formed on all the planned dividing lines 110, similar to the first embodiment. For example, as shown in Figures 12 and 13, if a dividing groove 165 is formed that penetrates both the front and back surfaces, the substrate 15 is divided into individual chips 167 for each device 166.

[0026] First alignment marks 161 and second alignment marks 162 are formed on the surface 16 of the substrate 15. However, in the later inspection step, inspection is performed from the back surface 17, so it is not possible to identify a defective device based on the first alignment marks 161 and second alignment marks 162. Therefore, first inspection marks 171 and second inspection marks 172 are formed on the back surface 17, having a predetermined positional relationship with the first alignment marks 161 and second alignment marks 162, so that the location of a defective device can be identified based on the first inspection marks 171 and second inspection marks 172. These first inspection marks 171 and second inspection marks 172 can be formed by creating a division base point inside by ablation processing by irradiation with laser light from the laser irradiation head 32 or by internal processing by irradiation with a laser beam of a penetrating wavelength, and by cracks extending from the division base point to the front and back surfaces.

[0027] (2-4) Examination Steps The inspection step is performed by imaging in the same manner as in the first embodiment. When a defective device is detected, its position is stored relative to the positions of the first inspection mark 171 and the second inspection mark 172. For example, the defective device 164 shown in Figure 12 is located four units in the +X direction and three units in the +Y direction from the first inspection mark 171, so its position is (+4, +3). The first inspection mark 171 is located -6 units in the -X direction and -6 units in the -Y direction from the first alignment mark 161. Therefore, relative to the first alignment mark 161, the defective device 164 is located at (-6+4, -6+3)=(-2, -3), and this information is stored in the memory unit. In this way, by forming inspection marks such as the first inspection mark 171 and the second inspection mark 172 on the back surface 17, the position relative to the alignment marks can be identified without imaging the front surface 16.

[0028] (2-5) Transfer step The transfer step is performed in the same manner as in the first embodiment. After the transfer step is completed, the divided substrate 15 is transported to, for example, a pickup device. The pickup device recognizes the location of the defective device 164 based on the position information (-2, -3) described above and excludes it from the pickup target. Therefore, even if the substrate rotates from its position on the inspection device's holding table when it is transported to the pickup device's holding table, causing its center position to shift, the defective area can be accurately identified based on the alignment marks, which are characteristic points of the substrate.

[0029] 3. Third Embodiment (3-1) Protective member formation step This step may be the same as in Figure 2 of the first embodiment, but here, as shown in Figure 3, a first protective member 20 with a larger diameter than the substrate 10 is attached to the surface 11 of the substrate 10, and a ring-shaped frame 23 is attached to the outer circumference of the adhesive surface 21 of the first protective member 20, so that the substrate 10 is supported by the frame 23 via the first protective member 20.

[0030] (3-2) Holding step As shown in Figure 14, the first protective member 20 is held on the holding table 61 of the cutting device 60. This exposes the back surface 12. The cutting device 60 is equipped with a cutting unit 62. The cutting unit 62 is configured with a cutting blade 621 mounted on the tip of a spindle 620, and the cutting blade 621 is held between a pair of flanges 622, and is movable in the Y-axis and Z-axis directions. Although not shown, the cutting device 60 is also equipped with an infrared camera (not shown) for detecting the planned division line 110 (see Figure 3) on the surface 11 side. If the holding table 61 is made of a transparent material, a camera may be provided below the holding table 61 instead of the infrared camera.

[0031] (3-3) Machining Steps In this step, the holding table 61 is moved horizontally in the direction of arrow 611, and the surface 11 is imaged via the back surface 12 using an infrared camera to detect the division line 110 shown in Figure 3. Then, the cutting blade 621 is rotated and positioned above the division line 110, and the holding table 61 is moved in the X-axis direction, and the cutting blade 621 is made to cut so that its lower end reaches the first protective member 20, thereby cutting the division line 110. Furthermore, by feeding the cutting blade 621 in the -Y direction by the interval of adjacent division lines 110 and cutting in the same manner, all division lines 110 in the same direction are cut. In addition, by rotating the holding table 61 by 90 degrees and performing the same cutting, all division lines 110 are cut vertically and horizontally, and the substrate 10 is divided into individual chips 113 for each device 111.

[0032] The subsequent inspection and transfer steps are carried out in the same manner as in the first or second embodiment. That is, in the inspection step, the position of the defective device may be recognized based on the notch 13 shown in Figure 8, or, if the first alignment mark 161 and second alignment mark 162 shown in Figure 12 are formed, the first inspection mark 171 and second inspection mark 172 may be formed in a predetermined positional relationship with them, and the position of the defective device may be recognized based on these.

[0033] The cutting device 60 shown in Figure 14 can be used to form the first inspection mark 171 and the second inspection mark 172. Specifically, the first protective member 20 is held on the holding table 61 of the cutting device 60, the cutting blade 621 is positioned above the position where the first inspection mark 171 and the second inspection mark 172 are to be formed, and without moving the holding table 61, the rotating cutting blade 621 is lowered to form a groove extending in the X direction, for example, by a so-called chopper cut. Next, after rotating the holding table 61 by 90 degrees, the cutting blade 621 is moved to the position of the groove extending in the X direction, and the rotating cutting blade 621 is lowered to form a groove extending in the Y direction by a chopper cut. In this way, the cross-shaped first inspection mark 171 and the second inspection mark 172 can be formed.

[0034] The inspection step and the transcription step are carried out in the same manner as in the first or second embodiment.

[0035] 4. Fourth Embodiment (4-1) Protective member formation step This step may be the same as in Figure 2 of the first embodiment, but as shown in Figure 3, a first protective member 20 with a larger diameter than the substrate 10 is attached to the surface 11 of the substrate 10, and a ring-shaped frame 23 is attached to the outer circumference of the adhesive surface 21 of the first protective member 20, so that the substrate 10 is supported by the frame 23 via the first protective member 20.

[0036] (4-2) Holding step As shown in Figure 15, the first protective member 20 is held on the rotatable holding table 71 of the protective film forming apparatus 70. This exposes the back surface 12. In addition to the holding table 71, the protective film forming apparatus 70 is equipped with a nozzle 72 for dispensing liquid resin.

[0037] (4-3) Machining Steps (4-3-1) Protective film formation step As shown in Figure 15, the holding table 71, which holds the substrate 10 via the first protective member 20, is rotated, and the nozzle 72 is positioned above the center of the substrate 10, and liquid resin 720 is discharged from the nozzle 72. As a result, the liquid resin 720 is spin-coated onto the back surface 12 of the substrate 10, and a protective film 73 is covered on one surface of the back surface 12. Alternatively, instead of liquid resin, resin may be supplied on a spray, or powdered resin may be supplied and melted by heat, or a sheet of resin may be attached to form the protective film 73.

[0038] (4-3-2) Exposure Step Next, the substrate 10, which has a protective film 73 coated on its back surface 12, is transported to the laser processing apparatus 30, and the side with the first protective member 20 is held on the holding table 31, as shown in Figure 16. This laser processing apparatus 30 is configured in the same way as the laser processing apparatus 30 shown in Figure 4.

[0039] As shown in Figure 16, with the first protective member 20 held on the holding table 31, the holding table 31 is moved horizontally in the direction indicated by the arrow 310, and the surface 11 is imaged via the back surface 12 using the infrared camera 33 to detect the division line 110 shown in Figure 3. Then, the laser irradiation head 32 irradiates the detected division line 110 with laser light 321 of a wavelength absorbed by the protective film 73, and the laser irradiation head 32 and the holding table 31 are moved horizontally relative to each other, thereby ablating the protective film 73 along the division line 110 to form grooves 731 and exposing the area of ​​the back surface 12 of the substrate 10 corresponding to the division line 110. Then, the same processing is performed while moving the laser irradiation head 32 by the interval of the division line 110, and once grooves 731 have been formed along all the division lines 110 in the same direction, the holding table 31 is rotated 90 degrees and the same ablating process is performed. As a result, the protective film 73 is divided vertically and horizontally by the grooves 731, exposing all of the planned division lines 110.

[0040] The exposure step can be performed using the cutting device 60 shown in Figure 14, by cutting the cutting blade 621 into the protective film 73. In this case, since cutting water is used, a water-insoluble protective film is applied to the back surface 12 of the substrate 10 during the protective film formation step.

[0041] (4-3-3) Etching Step Next, as shown in Figure 17, the first protective member 20 is held on the holding table 81 of the plasma etching apparatus 80. Then, the holding table 81 and the substrate 10 held thereon are moved into the chamber, and etching gas 82 is introduced from above using the divided protective film 73 as a mask to etch the division lines 110 of the substrate 10, forming division grooves 119 that penetrate both the front and back surfaces of the substrate 10 along the division lines 110. As a result, the substrate 10 is divided into individual chips 117.

[0042] (4-3-4) Protective film removal step Next, as shown in Figure 18, the protective film is removed. For example, if the protective film is made of a water-soluble resin, the first protective member 20 is held on the holding table 91 of the cleaning device 90, and the protective film 73 is removed by spraying water 920 from the nozzle 92. If a non-water-soluble material is used as the protective film 73, the protective film is removed by chemical cleaning. The protective film can also be removed by ashing. If the protective film is an oxide film or a metal film, it is not removed and the process proceeds to the next step.

[0043] The subsequent inspection and transcription steps are carried out in the same manner as in the first and second embodiments.

[0044] 5. Fifth Embodiment (5-1) Protective member formation step This step is carried out in the same manner as in the third embodiment.

[0045] (5-2) Holding step This step is also carried out in the same manner as in the third embodiment.

[0046] (5-3) Machining Steps (5-3-1) Protective film formation step This step is also carried out in the same manner as the fourth embodiment shown in Figure 15.

[0047] (5-3-2) Exposure Step This step is also carried out in the same manner as the fourth embodiment shown in Figure 16.

[0048] (5-3-3) Step for forming the removal area corresponding to the inspection mark In this step, laser ablation is used to form inspection marks on the substrate 10, which will serve as a reference for identifying the location of defective devices in a later inspection step. For example, as shown in Figure 19, laser irradiation from the laser irradiation head 32 forms an inspection mark corresponding removal portion 732 on the protective film 73 at a location that does not face the device 111.

[0049] (5-3-4) Etching Step This step is carried out in the same manner as the fourth embodiment shown in Figure 17, but since the inspection mark corresponding removal portion 732 is formed in the inspection mark corresponding removal portion formation step, not only the planned division line 110 but also the corresponding portion of the back surface 12 of the substrate 10 that is exposed by the inspection mark corresponding removal portion 732 is etched. As a result, an inspection mark corresponding to the inspection mark corresponding removal portion 732 is formed on the back surface 12 of the substrate 10.

[0050] (5-3-5) Protective film removal step This step is carried out in the same manner as the fourth embodiment shown in Figure 18.

[0051] In the subsequent inspection and transfer steps, the location of the defective device is identified based on the inspection marks formed in the etching step.

[0052] 6. Sixth Embodiment The substrate 18 shown in Figure 20 has an orientation flat 19 formed on it as a mark indicating the crystal orientation. The same method as in the second to fifth embodiments can be used with this substrate 18 as well, but when identifying a defective device 114 based on the orientation flat 19 in the inspection step and transfer step, for example, the center of the orientation flat in the X direction is used as a reference, and the position of the defective device 114 is determined by the displacement from there. In the substrate 18 shown in Figure 20, the position of the defective device 114 can be represented as (-4, +8).

[0053] 7 Seventh Embodiment When inspecting the processing quality of a substrate 10 on which a notch 13 as shown in Figure 1 has been formed, the center 200 of the substrate 10 shown in Figure 21 may be used as a feature point in the inspection step and the transfer step. To determine the position of the center 200 of the substrate 10, for example, the substrate 10 is moved in the X-axis direction while imaging is performed from above by an imaging unit (not shown), and the coordinates (x1, y1) and (x2, y2) of two points 201 and 202, where changes in height or brightness are detected as shown in Figure 22, are stored in the memory unit. Next, the substrate 10 is moved relative to the imaging unit in the X-axis and Y-axis directions, and the coordinates (x3, y3) and (x4, y4) of two points 203 and 204, where changes in height or brightness are detected, are stored in the memory unit. Then, for example, draw the perpendicular bisector 205 of the line connecting point 201 and point 202, and further draw the perpendicular bisector 206 of the line connecting point 201 and point 203, and the intersection of perpendicular bisectors 205 and 206 will be the center 200.

[0054] In the inspection and transfer steps, when identifying the location of the defective device 114 with respect to the center 200, as shown in Figure 20, the defective device 114 is located at a position displaced 4 units in the -X direction and 3 units in the +Y direction from the center 200, so the location of the defective device 114 is represented as (-4, 3). In this way, by using the center 200 of the substrate 10 as a feature point, the location of the defective device 114 can be recognized even from the back surface 12.

[0055] 8. Eighth Embodiment When inspecting the processing quality of a substrate 18 on which the orientation flat 19 shown in Figure 20 has been formed, the center 300 of the substrate 18 shown in Figure 23 can be used as a feature point in the inspection step and the transfer step. To determine the position of the center 300 of the substrate 18, for example, the substrate 18 is moved relative to an imaging unit (not shown) in the X-axis and Y-axis directions while imaging is performed from above by the imaging unit, and the positions where changes in height or brightness are detected are plotted in the XY plane coordinate system, drawing the outline 180 of the substrate 18 as shown in Figure 24(a).

[0056] Next, as shown in Figure 24(b), line 301 is obtained by finding and plotting the center coordinates of all two opposing points in the X-axis direction among the plots that constitute the outline 180 of the substrate 18, and connecting all the plots. Similarly, line 302 is obtained by finding and plotting the center coordinates of all two opposing points in the Y-axis direction among the plots that constitute the outline 180 of the substrate 18, and connecting all the plots.

[0057] Lines 301 and 302 are affected by the orientation flat 19, resulting in partially bulging line segments. Therefore, the intersection of lines 301 and 302 cannot be the center of the substrate 18. While this configuration calculates all center coordinates in the X and Y directions from the outline 180 of the substrate 18, it is not always necessary to calculate all center coordinates, and this can be modified as appropriate depending on the calculation accuracy.

[0058] Next, as shown in Figure 24(c), the average value of the X coordinates of the plots that make up line 301 is calculated, and an average line 303 is drawn parallel to the Y axis, passing through this average X coordinate. As a result, plots with an X coordinate smaller than the average are located to the left of average line 303, and plots with an X coordinate larger than the average are located to the right of average line 303. Then, the number of plots located to the left of average line 303 is compared with the number of plots located to the right of average line L3, and all plots on the side with fewer plots are discarded. In Figure 24(c), all plots to the right of average line 303 are discarded.

[0059] Similarly, the average Y-coordinate of the plots that make up line 302 is calculated, and an average line 304 is drawn parallel to the X-axis, passing through this average value. As a result, plots with a Y-coordinate greater than the average value are positioned above average line 304, and plots with a Y-coordinate smaller than the average value are positioned below average line 304. The number of plots above average line 304 is then compared to the number of plots below average line 304, and all plots on the side with fewer plots are discarded. In Figure 24(c), all plots above average line 304 are discarded.

[0060] Next, as shown in Figure 24(d), the average value of the X coordinates of the plots that make up line 301, excluding the discarded plots, is calculated, and average line 305 is drawn. Then, the number of plots to the left and right of average line 305 is compared, and all plots on the side with fewer plots (to the right of average line 305) are discarded. Similarly, the average value of the Y coordinates of the plots that make up line 302, excluding the discarded plots, is calculated, and average line 306 is drawn. Then, the number of plots above and below average line 306 is compared, and all plots on the side with fewer plots (above average line 306) are discarded.

[0061] By repeating the average line calculation process in this manner, the intersection point of the average line of line 301 and the average line of line 302 approaches the center coordinates of the substrate 18. In this embodiment, as shown in Figure 24(e), the intersection point of average lines 307 and 308 after repeating the above process twice is taken as the provisional center position of the substrate 18.

[0062] In the inspection and transfer steps, when identifying the location of the defective device 114 with respect to the center 300, as shown in Figure 23, the defective device 114 is located at a position displaced 4 units in the -X direction and 3 units in the +Y direction from the center 200, so the location of the defective device 114 is represented as (-4, 3). In this way, by using the center 200 of the substrate 10 as a feature point, the location of the defective device 114 can be recognized even from the back surface 12.

[0063] Alternatively, this method may be used to determine the position of the center 200 of the substrate 10 on which the notch 13 is formed.

[0064] 9. Ninth Embodiment In the processing steps of the first to sixth embodiments described above, a thinning step may be performed to thin the substrate 10 using the grinding device 95 shown in Figure 25 before dividing the substrate. This grinding device 95 includes a holding table 97 that can hold and rotate the substrate 10, and a grinding mechanism 96 that grinds the substrate 10 held on the holding table 97. The grinding mechanism 96 includes a rotatable spindle 961, a mount 962 attached to the lower end of the spindle 961, and a grinding wheel 965 attached to the mount 962. The grinding wheel 965 consists of a base 963 fixed to the mount 962 and a grinding wheel 964 fixed to the lower surface of the base 963.

[0065] In the grinding apparatus 95, the substrate 10 is held on the holding table 97 via the first protective member 20. As the holding table 97 rotates, the grinding wheel 965 rotates and descends, and the rotating grinding wheel 964 contacts the back surface 12 of the substrate 10, thereby grinding the back surface 12. When the substrate 10 is formed to the desired thickness, the grinding mechanism 96 is raised to end the grinding. After the substrate 10 has been formed to the desired thickness, the substrate 10 is divided into individual chips 113 for each device 111 using the laser processing apparatus 30 shown in Figure 4, the cutting apparatus 60 shown in Figure 14, and the plasma etching apparatus 80 shown in Figure 17.

[0066] As described above, in the inspection step of inspecting the processing quality from the back surface of the substrate, the defective area is stored based on characteristic points of the substrate, such as notches, orientation flats, the center point of the substrate, and inspection marks. Unlike the front surface, the back surface does not have any patterns or other references for identifying the location of the defective area. However, by storing the location of the defective area based on characteristic points of the substrate, the location of the defective area can be identified without imaging the front surface. [Explanation of Symbols]

[0067] 10: Circuit board 11: Surface 110: Planned division line 111: Device 112: Division groove 113: Chip 114: Faulty device 12: Back side 13: Notch 15: Circuit board 16: Surface 160: Planned division line 161: First alignment mark 162: Second alignment mark 164: Defective device 165: Split groove 166: Device 167: Chip 17: Reverse side 171: First inspection mark 172: Second inspection mark 18: Circuit board 19: Orientation flat 20: First protective component 21: Adhesive surface 23: Frame 25: Second protective component 30: Laser processing equipment 31: Holding table 32: Laser irradiation head 33: Infrared camera 34: Holding table 35: Imaging unit 40: Inspection device 41: Inspection table 42: Imaging unit 50: Transfer device 51: Table 52: Roller 60: Cutting device 61: Holding table 62: Cutting unit 620: Spindle 621: Cutting blade 622: Flange 70:Protective film forming device 71: Holding Table 72: Nozzle 720: Liquid resin 73: Protective film 731: Groove 732: Removal area corresponding to inspection mark 80: Plasma etching apparatus 81: Holding table 82: Etching gas 90: Washing device 91: Holding table 92: Nozzle 920: Water 95: Grinding equipment 96: Grinding mechanism 961: Spindle 962: Mount 963: Base 964: Grinding wheel 965: Grinding Wheel 97: Holding Table

Claims

1. A method for processing a substrate, wherein a substrate having a pattern and a plurality of division lines formed on its surface is processed along the division lines, A holding step in which the surface of the substrate is held on a holding table, A processing step in which the planned division line on the surface is detected from the front side via the holding table or from the back side by an infrared camera, and the substrate is processed from the back side by a processing unit along the planned division line, An inspection mark forming step in which an inspection mark is formed on the back surface by the processing unit, based on the alignment mark formed on the surface, After the processing step and the inspection mark formation step, an inspection step is performed in which the substrate is placed on an inspection table and the processing quality is inspected from the back side. Equipped with, The inspection step is characterized by storing the defective area based on the inspection mark. Methods for processing circuit boards.

2. The processing step and the inspection mark formation step are characterized by forming one of the following: a dividing groove that divides the substrate, a processing groove that does not divide the substrate, or a modified layer formed inside the substrate. The method for processing a substrate according to claim 1.

3. The processing step is, A protective film formation step in which a protective film is formed on the back surface of the substrate, After the protective film formation step, the processing unit is used to remove the protective film formed on the dividing line, exposing the dividing line in an exposure step. The process includes an etching step in which plasma etching is performed from the back surface after the exposure step, and the substrate is processed along the planned division line. The inspection mark formation step is: The method for processing a substrate according to either claim 1 or 2, characterized in that the processing unit removes the protective film in the shape of the inspection mark at an arbitrary position, and in the etching step, the inspection mark is formed on the back surface of the substrate.

4. Prior to the processing step, a protective member forming step is provided in which a first protective member is formed on the surface. The method is characterized by comprising a transfer step after the inspection step, in which a second protective member is formed on the back surface and the first protective member is peeled off from the front surface. A method for processing a substrate according to any one of claims 1, 2, or 3.

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