Method for preparing frame units for transport

Abstract

To confirm whether a unit for conveying frame units in a processor is adjusted to match the size of an annular frame.SOLUTION: The size of an annular frame of a frame unit in which a substrate is held through a sheet in the opening of the annular frame is registered, and a gap between the pair of guides on which the annular frame is placed is adjusted to match the registered size. Then, a suction portion 83 of a transfer arm 8 is positioned at a position where the suction portion contacts the upper surface 42 of a guide and suction is performed, and when a measured value of a pressure gauge at that time exceeds a threshold value, it is determined that the position of the suction portion 83 of the transfer arm 8 matches the size of the annular frame.SELECTED DRAWING: Figure 5

Description

Technical Field

[0006] , , ,

[0001] The present invention relates to a method for preparing the conveyance of a frame unit that checks the size of an annular frame before conveying a frame unit in which a substrate is held via a sheet at an opening of the annular frame.

Background Art

[0002] The annular frame of a frame unit configured such that a substrate is supported by an annular frame via a sheet has a plurality of sizes. And in various devices that process the frame unit, in order to accommodate annular frames of multiple sizes, the suction pads provided on the transfer arm within the device, the frame support unit that supports the frame around the holding table, etc. can be adjusted in position according to the size of the annular frame (see, for example, Patent Document 1 and Patent Document 2).

Prior Art Documents

Patent Documents

[0003] 2]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] If there is a work omission in the position adjustment of the suction pad of the transfer arm or the frame support unit installed around the holding table, there is a risk that the frame unit may be conveyed in a state where these do not match the size of the annular frame, resulting in an error.

[0005] On the other hand, in order to check whether the size of the annular frame matches the size of each unit such as the frame support unit, it is possible to install sensors or cameras, but this is costly.

[0006] This invention has been made in view of such problems, and aims to provide a way to verify, without increasing costs, whether each unit that transports or holds the frame unit within the processing apparatus is adjusted to fit the size of the annular frame. [Means for solving the problem]

[0007] The present invention comprises a pair of guides supporting both ends of a frame unit in which a substrate is held via a sheet in an opening of an annular frame; a holding table including a frame support unit that supports the annular frame; a processing unit that processes the frame unit held on the holding table; a transport arm having a suction part that is movable according to the size of the annular frame and that picks up the annular frame, and that transports the frame unit from the guides to the holding table; a pressure gauge installed in a suction path that connects the suction part and a suction source; a drive unit that adjusts the spacing of the guides according to the size of the annular frame; and a control unit. A method for preparing a frame unit for transport in a transport apparatus, for confirming whether the suction part is adjusted to the size of the annular frame, comprising: a size registration step of registering the size of the annular frame in the control unit; a guide adjustment step of adjusting the spacing of the guides to the size registered in the size registration step; a first suction step of positioning the suction part in contact with the upper surface of the guide and suctioning it after the guide adjustment step has been performed; and a first determination step of determining that the position of the suction part of the transport arm matches the size of the annular frame if the measurement value of the pressure gauge exceeds a threshold value. In the above method for preparing a frame unit for transport, it is desirable to include, when the frame support unit is installed outside the holding table so as to be movable according to the size of the annular frame, a second suction step of positioning the suction part, which was determined to match the size of the annular frame in the first determination step, in a position to contact the frame support unit and performing suction, and a second determination step of determining that the position of the frame support unit matches the size of the annular frame when the pressure gauge exceeds a threshold. [Effects of the Invention]

[0008] In this invention, the position of the suction part of the transport arm is confirmed based on a guide that is adjusted according to the size of the annular frame. Therefore, it is possible to confirm whether the position of the suction part of the transport arm is correct without using any additional parts. Consequently, it is possible to prevent errors from occurring when the frame unit is transported by the transport arm. Furthermore, since the position of the frame support unit is confirmed based on the suction part that was determined to match the size of the annular frame in the first determination step, it is possible to confirm whether or not the frame support unit is compatible with the size of the annular frame without using any additional parts. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view showing an example of a cutting device, which is an example of a processing device. [Figure 2] This is a perspective view showing an example of a frame unit. [Figure 3] This is a perspective view showing an example of a retention table. [Figure 4] This is a perspective view showing an example of a transport mechanism. [Figure 5] This is a plan view showing the suction part of the transport mechanism in contact with the guide of the positioning mechanism. [Figure 6] This is a plan view showing the state in which the suction part of the transport mechanism is not in contact with the guide of the positioning mechanism. [Figure 7] This is a plan view showing the suction part of the transport mechanism in contact with the frame support unit of the holding table. [Figure 8] This is a plan view showing the state in which the suction part of the transport mechanism is not in contact with the frame support unit of the holding table. [Figure 9] This is a plan view showing a part of the suction section of the transport mechanism in contact with the frame support unit of the holding table. [Modes for carrying out the invention]

[0010] 1. Configuration of the cutting device The cutting apparatus 1 shown in Figure 1 is a device for cutting various substrates 11. The substrate 11, which is the workpiece, is attached to a sheet 12, and the sheet 12 is attached so as to close the opening of the annular frame 13, thus forming a frame unit 10 as a whole. The substrate 11 shown in Figure 2 as an example is a semiconductor wafer partitioned by division lines 110 and having multiple devices 111 formed on its surface. The annular frame 13 has a circular inner circumference and is provided with straight sections 130 on all four sides of its outer circumference. The annular frame 13 is available in multiple sizes depending on the diameter of the substrate 11. For example, if the substrate 11 is a semiconductor wafer, the size of the substrate 11 may be, for example, 6 inches and 8 inches, and two different sizes of annular frame 13 are available accordingly. The annular frame 13 of different sizes has different distances 14 between two opposing parallel straight sections 130.

[0011] The cutting apparatus 1 includes a cassette mounting area 2 on which a cassette 21 containing a plurality of frame units 10 is placed, a push-pull mechanism 3 for loading and unloading the frame units 10 to and from the cassette 21, a positioning mechanism 4 for positioning the frame units 10 in a fixed position, a holding table 5 for holding the frame units 10, two cutting units 6 for cutting the substrate 11 held on the holding table 5, a cleaning mechanism 7 for cleaning the substrate 11 after cutting, and a transport arm 8 for transporting the frame units 10 between the positioning mechanism 4 and the cleaning mechanism 7.

[0012] The cassette mounting area 2 is movable up and down. The cassette 21 has multiple slots inside, and each slot houses a frame unit 10.

[0013] The push-pull mechanism 3 includes a clamping portion 31 that clamps the annular frame 13, an arm 32 that supports the clamping portion 31, a lifting drive portion 33 that moves the clamping portion 31 and the arm 32 up and down in the Z-axis direction, and a moving portion 34 that moves the lifting drive portion 33 in the Y-axis direction along a rail 35 extending in the Y-axis direction.

[0014] The positioning mechanism 4 includes a pair of guides 41 extending in the Y-axis direction. Each guide 41 is a member having an L-shaped cross-section composed of a placement surface 42 on which the annular frame 13 is placed, which is a plane parallel to the XY plane, and a wall portion 43 erected from the end portion in the X-axis direction of the placement surface 42, and the wall portion 43 of one guide 41 and the wall portion 43 of the other guide 41 face each other in the X-axis direction. The positioning mechanism 4 includes a drive portion 44 that drives the pair of guides 41 to approach or separate from each other in the X-axis direction, and the interval between the two guides 41 can be adjusted according to the size of the annular frame 13 based on the size of the annular frame stored in the storage portion.

[0015] As shown in FIG. 3, the holding table 5 includes a suction portion 51 that sucks and holds the substrate 11 via the sheet 12, a frame body 52 that supports the suction portion 51, four frame support units 53 fixed to the outer peripheral portion of the frame body 52, and a rotation drive portion 57 that rotates these around the rotation axis in the Z-axis direction. The holding surface 510, which is the upper surface of the suction portion 51, and the upper surface 520 of the frame body 52 are formed flush. Each frame support unit 53 is slidable along a pair of shaft portions 530 extending outward from the frame body 52 and is movable according to the size of the annular frame 13. Each frame support unit 53 includes a support plate 54 that supports the annular frame 13 from below, a pressing portion 55 that is rotatable about a horizontal axis with respect to the support plate 54 and presses the annular frame 13 placed on the support plate 54 from above to clamp it between the support plate 54, and a drive portion 56 that rotationally drives the pressing portion 55.

[0016] The cutting unit 6 shown in FIG. 1 is a processing unit that performs a cutting process on the substrate 11. The two cutting units 6 are provided with a cutting blade 61 that rotates about an axis in the Y-axis direction. The two cutting units 6 are movable in the Y-axis direction and the Z-axis direction.

[0017] The cleaning mechanism 7 is rotatable and vertically movable, and includes a spinner table 71 that holds the workpiece unit 10 after cutting of the substrate 10 and is capable of high-speed rotation, and a nozzle (not shown) that ejects a cleaning liquid onto the substrate 11 held and rotated by the spinner table 71.

[0018] As shown in FIG. 4, the transfer arm 8 includes a first arm 81 extending in the X-axis direction, a pair of second arms 82 extending in the Y-axis direction that intersects the first arm 81 horizontally, and suction portions 83 respectively attached to the lower surface side of each second arm 82 in two. The suction portion 83 communicates with a negative pressure generating unit 84 via a suction passage 85. A pressure gauge 86 is connected to the suction passage 85. A brancher (not shown) is disposed on the lower surface side of the second arm 82, and the upper surface of the first arm 81 is provided with a plurality of concave fitting portions 810 into which the tip of the brancher is fitted. That is, the second arm 82 can be slid in the direction of the arrow 820, which is the extending direction of the first arm 81, and the tip of the brancher can be fitted into the fitting portion 810 to be fixed. By manually changing the position of the second arm 82, the position of the suction portion 83 can be adjusted according to the size of the annular frame 13. As shown in FIG. 1, the first arm 81 is supported by a lifting drive unit 87 so as to be movable up and down. The lifting drive unit 87 is movable in the Y-axis direction along a guide rail 88 extending in the Y-axis direction.

[0019] The cutting device 1 includes a cassette placement area 2, a push-pull mechanism 3, a positioning mechanism 4, a holding table 5, a cutting unit 6, a cleaning mechanism 7, a transfer arm 8, and a control unit 9 that controls each unit.

[0020] 2. Operations during cutting In the cutting apparatus 1 shown in Figure 1, a cassette 21 containing multiple frame units 10 arranged in multiple stages is placed on the cassette mounting area 2. First, the cassette mounting area 2 is raised and lowered to align the height of the slot containing the frame unit 10 with the substrate 11 to be cut with the height of the clamping portion 31 of the push-pull mechanism 3. Then, the distance between the walls 43 of the two guides 41 is made slightly larger than the size of the annular frame 13. With this in place, the push-pull mechanism 3 is moved in the -Y direction to clamp the annular frame 13 with the clamping portion 31. After that, the push-pull mechanism 3 is moved in the +Y direction to place the frame unit 10 on the mounting surface 42 of the guide 41, and the guide 41 supports both ends of the frame unit 10 in the X-axis direction. After that, the clamping portion 31 releases the annular frame 13, and the push-pull mechanism 3 is retracted in the +Y direction.

[0021] Next, the drive unit 44 moves the pair of guides 41 toward each other, and the wall portion 43 pushes both ends of the annular frame 13, thereby positioning the frame unit 10 in a fixed position. Then, the transport arm 8 is moved in the -Y direction to position it above the frame unit 10, and in that state, the transport arm 8 is lowered, bringing the suction portion 83 into contact with the upper surface of the annular frame 13, and the suction portion 83 is connected to the negative pressure generating unit 84, thereby picking up the annular frame 13. After the drive unit 44 moves the pair of guides 41 toward each other, the lifting drive unit 87 raises the transport arm 8, thereby raising the frame unit 10.

[0022] The holding table 5 is moved in the +X direction to position it below the frame unit 10 held by the transport arm 8. Then, with the guide 41 separated, the lifting drive unit 87 lowers the transport arm 8 and places the frame unit 10, held by the suction unit 83, onto the holding table 5. That is, the substrate 11 is placed on the holding surface 510 and the annular frame 13 is placed on the support plate 54 of the frame support unit 53. Then, a suction force is applied to the suction unit 51 of the holding table 5, and the annular frame 13 is held between the support plate 54 and the pressing unit 55 of the frame support unit 53. Then, the suction of the transport arm 8 by the suction unit 83 is released, and the lifting drive unit 87 raises and retracts the transport arm 8.

[0023] Next, the holding table 5 moves in the -X direction, approaching the cutting unit 6. After the division line 110 to be cut is detected, the cutting blade 61 rotates as the holding table 5 moves in the -X direction, cutting into the detected division line 110, and that division line 110 is cut. Then, by repeating the same cutting while moving the cutting blade 61 in the Y direction, all division lines 110 in the same direction are cut. Furthermore, after rotating the holding table 5 by 90 degrees and performing the same cutting, all division lines 110 are cut vertically and horizontally, dividing them into individual chips for each device 111.

[0024] After cutting is complete, the holding table 5 returns to its original position (below the guide 41). With the guide 41 separated, the lifting drive unit 87 lowers the transport arm 8 to bring the suction part 83 into contact with the upper surface of the annular frame 13, connecting the suction part 83 with the negative pressure generating unit 84 to suction the annular frame 13. The lifting drive unit 87 then raises the transport arm 8, lifting the frame unit 10 above the guide 41, bringing the guide 41 slightly closer, and then lowers the transport arm 8 to place the frame unit 10 on the mounting surface 42 of the guide 41. The suction of the suction part 83 is released and the transport arm 8 is raised, and the guide 41 is brought closer and the frame unit 10 is positioned by pushing it from both sides with the wall part 43.

[0025] After the frame unit 10 is positioned in this way, the lifting drive unit 87 lowers the transport arm 8 again, bringing the suction part 83 into contact with the upper surface of the annular frame 13, and connecting the suction part 83 to the negative pressure generating unit 84 to suction the annular frame 13. Then, after separating the guide 41, the transport arm 8 is raised.

[0026] Next, the transport arm 8 is moved in the +Y direction to position the frame unit 10 above the spinner table 71 of the cleaning mechanism 7. Then, the transport arm 8 is lowered to place the frame unit 10 on the spinner table 71. The frame unit 10 is then held in place by suction on the spinner table 71, the suction of the suction part 83 is released, and the transport arm 8 is raised. Next, the surface of the substrate 11 is cleaned by spraying cleaning liquid onto the substrate 11 while the spinner table 71 is rotated at high speed. After cleaning is complete, high-pressure air is sprayed onto the substrate 10 to remove the cleaning liquid, the rotation of the spinner table 71 is stopped, the transport arm 8 is lowered to bring the suction part 83 into contact with the annular frame 13, and after connecting the suction part 83 with the negative pressure generating unit 84, the transport arm 8 is raised.

[0027] Next, the transport arm 8 is moved in the -Y direction and positioned above the guide 41. Then, the transport arm 8 is lowered and the frame unit 10 is placed on the mounting surface 42 of the guide 41. After positioning the frame unit 10 by bringing the guide 41 closer, the annular frame 13 is clamped by the clamping portion 31 of the push-pull mechanism 3, and the push-pull mechanism 3 is moved in the -Y direction to house the frame unit 10 in the original slot of the cassette 21.

[0028] By performing the above operations on all frame units 10 housed in the cassette 21, the circuit boards 11 that make up all frame units 10 are cut.

[0029] 3. Preparation method for transport The substrate 11 comes in various sizes, and the size of the annular frame 13 varies accordingly. Therefore, when cutting the substrate 11 as described above, the frame unit 10 must be smoothly transported within the cutting device 1 while accommodating the differences in the size of the annular frame 13. To this end, before performing actual cutting in the cutting device 1, it is checked whether the suction part 83 of the transport arm 8 is adjusted to match the size of the annular frame 13, as described below.

[0030] 1. Size Registration Step The size of the annular frame 13 supporting the substrate 11 to be cut is registered in the memory unit of the control unit 9. This registration is performed using an input means provided in the cutting device 1, such as a touch panel (not shown). For example, if it is input that the substrate 11 is 6 inches or 8 inches, the corresponding size of the annular frame 13 may be stored in the memory unit. Also, since the size of the annular frame 13 and the size of the substrate 11 may not match, such as supporting a 6-inch substrate 11 on an 8-inch annular frame 13 that can support an 8-inch substrate, the size of the annular frame 13 and the size of the substrate 11 may be input and registered separately in the memory unit. The size of the annular frame 13 is indicated, for example, by the distance 14 between the straight sections 130 of the annular frame 13 as shown in Figure 2. The inner diameter of the annular frame 13 or the size of the substrate 11 with the largest diameter that it can support may also be used as the size of the annular frame 13.

[0031] 2. Guide adjustment step Next, in the size registration step, the control unit 9 adjusts the spacing of the guides 41 of the positioning mechanism 4 to match the size of the annular frame 13 registered in the control unit 9. That is, the drive unit 44 drives the guides 41 to match the distance 45 between the two wall portions 43 that make up the guide 41 shown in Figure 5 to the distance 14 shown in Figure 2, which is the size of the annular frame 13. The spacing between the two wall portions 43 is left slightly larger (by a few millimeters) than the distance 14 of the annular frame 13.

[0032] 3. First suction step After the guide adjustment step is performed, the lifting drive unit 87 and the transport arm 8 are moved in the Y-axis direction along the guide rail 88 shown in Figure 1, positioning the suction unit 83 above the guide 41. Then, the lifting drive unit 87 lowers the transport arm 8, positioning the suction unit 83 in contact with the mounting surface 42 of the guide 41. Finally, the suction unit 83 is connected to the negative pressure generating unit 84, and a suction force is applied to the suction unit 83.

[0033] 4. First determination step Next, the control unit 9 reads the measurement value from the pressure gauge 86 shown in Figure 4. If the absolute value of the negative pressure measurement exceeds a predetermined threshold, it is considered that the suction part 83 is in close contact with the mounting surface 42, as shown in Figure 5, and the control unit 9 determines that the position of the suction part 83 matches the size of the annular frame 13. In the illustrated example, there are four suction parts 83, so the control unit 9 stores a predetermined threshold in its memory so that the absolute value of the negative pressure measurement exceeds the threshold only when all of them are in close contact with the mounting surface 42. On the other hand, if the absolute value of the negative pressure measurement from the pressure gauge 86 is smaller than a predetermined threshold, it is considered that the suction part 83 is not in close contact with the mounting surface 42, and it is determined that the position of the suction part 83 does not correspond to the size of the annular frame 13. For example, as shown in Figure 6, if the suction part 83 is located inside the guide 41 and does not contact the mounting surface 42, it is determined that the suction part 83 is in a position corresponding to a size smaller than the annular frame 13 it should correspond to, and an error message is displayed on a display unit (not shown).

[0034] In the example of the transport arm 8 shown in Figure 4, one negative pressure generating unit 84 is connected to each of the four suction parts 83, and one pressure gauge is connected to a suction passage 85 common to all of the suction parts 83. However, it is also possible to connect a pressure gauge individually to the suction passage corresponding to each suction part 83. In that case, the negative pressure measurements are read individually, and it is determined that the position of the suction part 83 is compatible with the size of the annular frame 13 when the absolute value of the negative pressure measurements at all the pressure gauges exceeds a predetermined threshold.

[0035] In this way, before cutting the substrate 11, by checking in advance whether the suction unit 83 is compatible with the size of the annular frame 13, using the guide 41 which is adjusted by the control unit 9 according to the size of the annular frame 13 as a reference, it is possible to prevent errors from occurring when the frame unit 10 is transported by the transport arm 8 without using any additional parts.

[0036] 5. Second suction step Next, the connection between the suction unit 83 and the negative pressure generating unit 84 is released to release the suction force of the suction unit 83, the pair of guides 41 are separated, and the transport arm 8 is lowered, so that the suction unit 83, which was determined to match the size of the frame unit 10 in the first determination step, is in contact with the support plate 54 or the pressing part 55 of the frame support unit 53 that constitutes the holding table 5, as shown in Figure 7. Then, the connection between the suction unit 83 and the negative pressure generating unit 84 is made, and a suction force is applied to the suction unit 83. Note that in Figure 7, the pressing part 55 shown in Figure 3 is omitted from the illustration.

[0037] 6. Second judgment step Next, the control unit 9 reads the measurement value from the pressure gauge 86 shown in Figure 4. If the absolute value of the negative pressure measurement exceeds a predetermined threshold, it is considered that the suction part 83 is in close contact with the support plate 54 or the pressing part 55, and the control unit 9 determines that the position of the frame support unit 53 matches the size of the annular frame 13. On the other hand, if the absolute value of the negative pressure measurement from the pressure gauge 86 is smaller than the predetermined threshold, it is considered that the suction part 83 is not in close contact with the support plate 54, and the control unit 9 determines that the position of the frame support unit 53 does not correspond to the size of the annular frame 13, and displays an error message on a display unit (not shown). For example, as shown in Figure 8, the position of the suction part 83 is inside the support plate 54, and the suction part 83 does not contact the support plate 54. Note that in Figure 8, the pressing part 55 shown in Figure 3 is not shown.

[0038] There is also a type of transport arm 8 with a longer second arm 89, as shown in Figure 9. In this case, even if the position of the suction parts 83 corresponds to the size of the annular frame 13, only two of the four suction parts 83 will contact the support plate 54, and the remaining two will not. In this case, a pressure gauge is individually connected to each suction path corresponding to each suction part 83. For example, as shown in Figure 9, if two opposing suction parts 83 of a pair of second arms 89 contact the support plate 54, and the absolute value of the measured negative pressure during suction exceeds a predetermined value, it is determined that it corresponds to the frame unit 10. Note that in Figure 9, the illustration of the retaining part 55 shown in Figure 3 is omitted.

[0039] In this way, the position of the frame support unit 53 of the holding table 5 is confirmed based on the suction part 83 which was determined to match the size of the annular frame 13 in the first determination step. Therefore, it is possible to confirm whether the frame support unit 53 is compatible with the size of the annular frame 13 without using any additional parts. Accordingly, it is possible to prevent errors from occurring when the frame unit 10 is transported by the transport arm 8.

[0040] In this embodiment, the cutting unit 6 that processes the frame unit 10 in the cutting device 1 was described as an example of a processing unit. However, other processing units include laser processing units in laser processing devices and grinding units in grinding devices. The target device is not limited to any device that uses a suction part to pick up an annular frame and transport the frame unit. [Explanation of Symbols]

[0041] 1:Cutting device 2: Cassette mounting area 21: Cassette 3: Push-pull mechanism 31: Clamping part 32: Arm 33: Lifting drive part 34: Moving part 35: Rail 4: Positioning mechanism 41: Guide 42: Mounting surface 43: Wall section 44: Drive unit 5: Holding Table 51: Suction part 510: Holding surface 52: Frame 520: Top surface 53: Frame support unit 530: Shaft section 54: Support plate 55: Pressing part 56: Drive unit 57: Rotary drive unit 6: Cutting unit 61: Cutting blade 7: Cleaning mechanism 71: Spinner table 8: Transport arm 81: First arm 810: Fitting part 82: Second arm 83: Suction part 84: Negative pressure generation unit 85: Suction passage 86: Pressure gauge 87: Lifting drive unit 88: Guide rail 89: Second arm 9: Control Unit 10: Frame Unit 11: Circuit board 110: Planned division line 111: Device 12: Sheet 13: Ring frame 130: Straight section 14: Distance

Claims

1. Guides supporting both ends of a frame unit in which a substrate is held via a sheet in an opening of an annular frame, A holding table including a frame support unit that supports the annular frame, A processing unit that processes the frame unit held in the holding table, A transport arm is provided which is movable according to the size of the annular frame and has a suction part that holds the annular frame in place, and which transports the frame unit from the guide to the holding table, A pressure gauge is installed in the suction path that connects the adsorption unit and the suction source, A drive unit that adjusts the spacing of the guides to match the size of the annular frame, Control unit and A method for preparing a frame unit for transport in a processing apparatus comprising the following, wherein the suction part is adjusted to the size of the annular frame: A size registration step in which the size of the annular frame is registered in the control unit, A guide adjustment step that adjusts the spacing of the guides to the size registered in the size registration step, After performing the guide adjustment step, a first suction step is performed to position the suction part in contact with the upper surface of the guide and then suction it. The method is characterized by comprising: a first determination step of determining that the position of the suction part of the transport arm matches the size of the annular frame when the measured value of the pressure gauge exceeds a threshold; Method for preparing frame units for transport.

2. The frame support unit is installed outside the holding table so as to be movable according to the size of the annular frame, A second suction step involves positioning the suction part, which has been determined to match the size of the annular frame in the first determination step, in a position where it contacts the frame support unit and then applying suction. A second determination step is to determine if the pressure gauge exceeds a threshold, and that the position of the frame support unit matches the size of the annular frame. Features that A method for preparing a frame unit for transport according to claim 1.

Images