JP3555063B2 - Optical bridge alignment device and probe device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an alignment device and a probe device for an optical bridge.
[0002]
[Prior art]
As shown in FIG. 5, for example, a conventional probe device 10 includes a loader chamber 11 for transporting a wafer W stored in a cassette C, and a transport mechanism (not shown) provided in the loader chamber 11. And a controller 13 for controlling the prober chamber 12 and the loader chamber 11, and a display device 14 serving as an operation panel for operating the controller 13. I have.
[0003]
A sub-chuck 15 is disposed in the loader chamber 11, pre-aligns the wafer W based on the orientation flat via the sub-chuck 15, and transfers the pre-aligned wafer W to the prober chamber 12 via a transfer mechanism. To be transported to
[0004]
In the prober chamber 12, a main chuck 18 that moves in the X, Y, Z, and θ directions via an X stage 16, a Y stage 17, and the like on which the wafer W is mounted, and is mounted on the main chuck 18. An alignment device (hereinafter, simply referred to as an “alignment device”) 20 of an optical bridge for accurately aligning the wafer W at an inspection position, and a probe needle for performing an electrical inspection of the wafer W aligned by the alignment device 20 are provided. And a probe card (not shown). The probe card is fixed via an insert ring to an opening at the center of a head plate that can be opened and closed with respect to the upper surface of the prober chamber 12. A test head (not shown) is rotatably disposed in the prober chamber 12, and electrically connects between the probe card and a tester (not shown) through the test head swiveled on the prober chamber 12. A predetermined signal from the tester is transmitted / received to / from the wafer W on the main chuck 18 via a probe card, and the tester sequentially performs an electrical inspection of a plurality of chips formed on the wafer W.
[0005]
By the way, when inspecting the wafer W, the wafer W on the main chuck 18 is aligned using the alignment device 20 in advance, and then each chip of the wafer W is inspected one by one accurately. As shown in FIGS. 5 and 6, the alignment apparatus 20 includes an imaging unit for imaging the wafer W or the like, for example, a CCD camera 21, an alignment bridge 22 equipped with the camera 21, and a reciprocating movement of the alignment bridge 22 in the Y direction. It includes a pair of left and right linear guides 23, 23 movably supported in the Y direction, and a pair of left and right drive mechanisms, such as air cylinders 24, that reciprocate according to the two linear guides 23, 23. The alignment bridge 22 is connected to an air cylinder 24 via a connecting member 25, and is moved in the Y direction by the air cylinder 24.
[0006]
In addition, the alignment device 20 includes a bridge fixing device 26 that fixes the alignment bridge 22 at the probe center. As shown in FIG. 6, the bridge fixing device 26 includes a fixing member 27 having a substantially L-shaped side surface attached to a front portion of the bottom surface of each of the left and right ends of the alignment bridge 22 in parallel with the moving direction. A roller 28 that engages the 90 ° curved surface of the member 27 to fix the alignment bridge 22 at the probe center, a lever 29 to which the roller 28 is rotatably mounted, and is pivotally attached to one end of the lever 29. Further, it is configured as a link mechanism including an air cylinder 31 for rotating the lever 29 forward and reverse around the support pin 30 at the other end. In addition, 32 is a shock absorber.
[0007]
Next, the operation of the alignment device 20 will be described. When aligning the wafer W, when a pair of left and right air cylinders (not shown) is driven, the alignment bridge 22 moves from the standby position in the Y direction according to the pair of left and right linear guides 23 to reach the probe center. When the air cylinder 31 of the instantaneous bridge fixing device 26 is driven to rotate the roller 28 counterclockwise through the link mechanism, the roller 28 engages with the curved surface of the fixing member 27 on the bottom surface of the alignment bridge 22, The alignment bridge 22 is momentarily pressed against the shock absorber 32. As a result, as shown in FIG. 6, the fixing member 27 is sandwiched between the roller 28 of the bridge fixing device 26 and the shock absorber 32, and the alignment bridge 22 is fixed at the probe center. In this state, alignment of the wafer W on the main chuck 18 is performed by cooperation between a camera mounted on the alignment bridge 22 and a camera fixed to the main chuck 18 (not shown). After the alignment, the air cylinder 31 is driven in the opposite direction, that is, in the direction of the arrow in the figure, to release the alignment bridge 22 from the bridge fixing device 26, and returns to the original standby position by the air cylinders as a pair of left and right drive mechanisms.
[0008]
[Problems to be solved by the invention]
However, in the case of the alignment device 20 in the conventional probe device, the roller 28 is pressed against the curved surface of the fixing member 27 by the air pressure of the air cylinder 31 of the bridge fixing device 26, and the alignment bridge 22 is fixed by the shock absorber 32. However, since the alignment bridge 22 slightly vibrates in the moving direction at the moment when it comes into contact with the shock absorber 32, it takes time until the vibration is attenuated, and the fixing of the alignment bridge 22 at the probe center is delayed. There was a problem that the delay in the start of the alignment operation was caused by this delay. Further, since the alignment bridge 22 is fixed by the air cylinder 31 and the shock absorber 32, the fixing position of the alignment bridge 22 is unstable, and the alignment bridge 22 may be slightly displaced from the original probe center. . In particular, if the chips of the wafer W become ultra-fine in the future, even if the displacement is on the order of microns, the original probing operation may be disturbed, and as a result, the reliability of the inspection is reduced.
[0009]
Further, in the case of the conventional alignment apparatus 20, the alignment bridge 22 is moved in the Y direction according to the linear guide 23. However, the linear guide 23 is a base that has extremely high precision in the X, Y and Z directions. Must be installed on a table (not shown). Moreover, in order to smoothly move the alignment bridge 22 in accordance with the linear guide 23, air cylinders for imparting a uniform driving force from the left and right of the alignment bridge 22 must be provided on the left and right. Since the alignment device 20 and the link mechanism are used, the structure of the alignment device 20 is complicated and costly.
[0010]
The present invention has been made in order to solve the above problems, and provides an alignment device for an optical bridge capable of instantly fixing an imaging means for alignment to a probe center and performing an alignment operation quickly. It is an object of the present invention to provide an optical bridge alignment device that can simplify the structure and reduce the cost. In addition, a probe which can fix the imaging means for alignment to the probe center in a short time to increase the throughput, simplify the structure and reduce the cost, and thereby improve the reliability of the inspection. The purpose is to provide the device together.
[0011]
[Means for Solving the Problems]
The alignment device for an optical bridge according to claim 1 of the present invention , Alignment bridge equipped with imaging means for aligning an inspection object, and this alignment bridge On A pair of left and right guide members movably supported between the probe center and the standby position above the mounting table and disposed on the probe device main body, and the alignment bridge is provided on at least one of the two guide members. A drive mechanism for moving the alignment bridge in accordance with each of the guide members, and a magnet for adsorbing the alignment bridge at both ends thereof and fixing the magnet at a probe center. On the body It is characterized by being provided respectively.
[0012]
The alignment device for an optical bridge according to claim 2 of the present invention includes: In the invention according to claim 1, From both ends of the above alignment bridge Protruding Left and right pair of fixing rods Are each Provide a solenoid to fit The solenoid, in the direction of current, cooperates with the magnet to attract the fixing rod, or to provide a repulsive force to offset the attractive force of the magnet. It is characterized by the following.
[0013]
The alignment device for an optical bridge according to a third aspect of the present invention is the alignment device according to the second aspect, When the alignment bridge returns to the standby position, Solenoid on the side without the above bridge drive mechanism Magnetic force The repulsion of , Solenoid having the above drive mechanism Magnetic force Is set to be larger than the repulsive force.
[0014]
According to a fourth aspect of the present invention, there is provided the alignment device for an optical bridge according to the third aspect of the present invention, wherein the left and right ends of the alignment bridge have a pair of left and right tapered surfaces parallel to the guide rods. And a positioning block having a reverse tapered surface for positioning the alignment bridge at the probe center by contacting the positioning projections with each other.
[0015]
Also, the probe device according to claim 5 of the present invention , Listed An alignment bridge that moves along a pair of left and right guide rods between a probe center and a standby position above the mounting table and includes an imaging unit for aligning an object to be inspected on the mounting table; A drive mechanism disposed on one of the two guide rods for moving in accordance with the rod; and a permanent magnet for attracting the alignment bridge at both ends thereof and fixing the alignment bridge at a probe center. On the body Solenoids are provided integrally with each of the permanent magnets, and a repulsive force capable of canceling the attraction force of each of the permanent magnets is provided integrally with each of the permanent magnets. And protruding from the portion in parallel with each of the guide rods.
[0016]
A probe device according to a sixth aspect of the present invention is the probe device according to the fifth aspect, wherein the solenoid having no drive mechanism is provided. Magnetic force The repulsion of , Solenoid having the above drive mechanism Magnetic force Is set to be larger than the repulsive force.
[0017]
According to a seventh aspect of the present invention, there is provided the probe device according to the fifth or sixth aspect, wherein the left and right ends of the alignment bridge have tapered surfaces vertically in parallel with the guide rods from both ends. A pair of positioning projections are protruded, and a positioning block having an inverse tapered surface for positioning the alignment bridge at a probe center by contacting the positioning projections is provided.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on the embodiment shown in FIGS.
The probe device of the present embodiment is configured according to a conventional probe device except for an alignment device of an optical bridge (hereinafter, simply referred to as an “alignment device”). Therefore, in the present embodiment, the alignment device will be mainly described. FIG. 1 and FIG. 2 show components of only the loader chamber side of the alignment apparatus of the present embodiment. As shown in FIGS. 1 and 4, for example, an alignment device 20 according to the present embodiment includes an alignment bridge 22 equipped with a camera 21 (see FIG. 4) that captures an image of the surface of the wafer W during alignment, and the like. A pair of left and right guides disposed in the prober chamber 12 so as to be movably supported between a probe center (vertically below the inspection center of the probe card P) and a standby position above the main chuck 18 (see FIG. 5). The rods 23, and a rodless air cylinder (hereinafter simply referred to as an “air cylinder”) 24 disposed directly below and parallel to the guide rod 23 on the loader chamber side of the two guide rods 23, 23. Have. Both ends of each of the guide rods 23 and the air cylinder 24 are supported by base columns 12A and 12B erected in the prober chamber 12 at the front and rear.
[0019]
A connection block 25 formed, for example, in a substantially rectangular shape is fixed to each of the left and right ends of the bottom surface of the alignment bridge 22, and the left guide rod is connected to the left end of the alignment bridge 22 via a connection block (not shown) on the left side of the prober chamber 12. And a sliding margin (extremely small gap). The right end of the alignment bridge 22 is connected to the right guide rod 23 and the air cylinder 24 via a connection block 25 with sliding margins. That is, through holes are formed vertically in the connection block 25, and a linear bush 23A is mounted in the upper through hole, and the alignment bridge 22 slides along the guide rod 23 via the linear bush 23A. . A moving body 24A of an air cylinder 24 is mounted in the lower through-hole, and the alignment bridge 22 moves along the cylinder 24B via the moving body 24A by the action of compressed air supplied to the air cylinder 24. is there. As described above, the alignment bridge 22 is reciprocated along the guide rod 23 by one air cylinder 24 disposed below the guide rod 23 on the right side (loader chamber side) of the prober chamber 12. The movement speed of the guide rod 23 without the guide rod 24 is slightly delayed, and the alignment bridge 22 is slightly inclined with respect to the guide rods 23 in the horizontal plane.
[0020]
As is apparent from FIG. 2, positioning projections are provided on the front surface (the left surface in FIG. 2) of each of the connection blocks 25. 26A Are fixed respectively. This positioning projection 26A Protrudes forward with the guide rod 23 and has a vertical tapered surface 26B, 26B Is formed. Each positioning protrusion is provided on the front base 12A. 26A Positioning block corresponding to 27A Has been fixed. This positioning block 27A Has a positioning projection 26A Tapered surface 26B, 26B Upper and lower reverse taper surface to engage with 27B, 27B Is formed. And positioning projections 26A And positioning block 27A Is in contact with the probe center.
[0021]
A fixing rod, a permanent magnet, and a solenoid are provided as devices for fixing the alignment bridge 22 at the probe center. Since the left and right fixing rods and solenoids have the same structure, the fixing rod and solenoid on the left side (loader chamber side) will be described with reference to FIGS. That is, each of the positioning protrusions 26A As shown in FIG. 1 and FIG. 28A Are extended vertically downward, and these board parts 28A Fixing rod made of ferromagnetic material 29A Are mounted in parallel with the guide rod 23. And a fixing rod is provided on the front base 12A. 29A For fixing the alignment bridge 22 at the probe center by suctioning 30A Has been fixed. This fixing means 30A Is, as shown in FIG. Front Ring-shaped permanent magnet placed in 30B And this permanent magnet 30B Solenoid located on the back side of the 30C And a solenoid 30C The direction of the current flowing through is switched. Therefore, for example, when fixing the alignment bridge 22 at the probe center, a permanent magnet 30B And solenoid 30C By fixing rod 29A And the alignment bridge 22 is stopped at the probe center. Conversely, when returning the alignment bridge 22 to the standby position, the solenoid 30C Fixing rod by reversing the direction of the current 29A Gives repulsion to permanent magnets 30B Rod for fixing 29A But fixing means 30A It is made to escape from smoothly. Also permanent magnet 30B Is simply a fixing rod 29A In addition to sucking the alignment, the alignment bridge 22 moving from the standby position as a larger role is instantaneously fixed at the probe center, and the waiting time until the start of alignment is almost eliminated, so that the alignment can be started in a short time. Has a function. When the alignment bridge 22 is located at the probe center and the standby position, the left and right fixing means 30A Solenoid 30C Are in a non-excited state.
[0022]
As described above, the alignment bridge 22 is driven by one air cylinder 24, and the alignment bridge 22 is driven by the guide rod 23 without the air cylinder 24. Therefore, the alignment bridge 22 is driven by the one without the air cylinder 24. Movement is slightly delayed. Therefore, if the alignment bridge 22 moves in a state where the side without the air cylinder 24 (left side) is delayed, the alignment bridge 22 is inclined in the left-right direction, and there is a possibility that galling occurs between the connecting block 25 and the linear bush 23A.
[0023]
Therefore, in this embodiment, when the alignment bridge 22 returns from the probe center to the standby position, the left solenoid without the air cylinder 24 is used. 30C The repulsive force of the solenoid of the right solenoid with air cylinder 24 30C Is generated, for example, 1.5 times the repulsion force. When returning the alignment bridge 22 from the probe center to the standby position, the solenoid on the left side 30C The permanent magnet on the left due to the magnetic flux 30B Rods to offset the adsorption effect of 29A The rod for fixation almost eliminates the suction power of 29A But fixing means 30A From the left side, the fixing means on the left side 30A The delay of the alignment bridge 22 in the inside is eliminated. When the alignment bridge 22 moves from the standby position to the probe center, the left solenoid without the air cylinder 24 is used. 30C Suction force and the right solenoid with air cylinder 24 30C And the right and left fixing rods 29A Is sucked with a uniform suction force, so that the inclination of the alignment bridge 22 is eliminated.
[0024]
A base 12C extending rearward is formed on the front base 12A so as to be located below the solenoid 30, and a shock absorber is provided on the base 12C. 31A Are arranged. As a result, the alignment bridge 22 moves from the standby position to the probe center by the action of the air cylinder 24, 30A Is a fixing rod 29A When the alignment bridge 22 starts to move to the probe center rapidly, the connecting block 25 of the alignment bridge 22 is moved to the shock absorber immediately before the stop position. 31A Abuts the positioning projection 26A And positioning block 27A Shock when the probe contacts the probe center 31A To ease it.
[0025]
Next, the operation of the probe device using the alignment device 20 of the present embodiment will be described with reference to FIG. For example, when a wafer W is transferred from the loader chamber 11 onto the main chuck 18 in the prober chamber 12, the X and Y stages 16 and 17 are driven to move the main chuck 18 to the probe center. Next, the air cylinder 24 of the alignment apparatus 20 shown in FIG. 1 is driven, and the alignment bridge 22 moves from the standby position to the probe center according to the guide rod 23 and the cylinder 24B via the moving body 24A of the air cylinder 24. At this time, since there is only one air cylinder 24, the movement of the alignment bridge 22 is slightly delayed in the direction without the air cylinder 24, and the alignment bridge 22 is slightly inclined with respect to both guide rods 23 in the horizontal plane. But this inclination is a fixing means 30A Is a fixing rod 29A Is eliminated during suction. At this point, the fixing means 30A A positive current flows through the 29A Can be sucked.
[0026]
Thereafter, the alignment bridge 22 approaches the probe center, and as shown in FIG. 29A Are the corresponding fixing means 30A When approaching inside, a permanent magnet 30B And excited solenoid 30C Rod for fixing inside 29A Aspirate strongly. As a result, the minute vibration of the alignment bridge 22 quickly stops, and the waiting time for starting the alignment becomes extremely short. At this time, just before the alignment bridge 22 reaches the probe center, the alignment bridge 22 31A Tangled with the fixing means 30A The movement speed of the alignment bridge 22 is braked. Therefore, positioning projections 26A Is the positioning block 27A When it comes into contact without impact, the permanent magnet 30B Fixed by rod 29A And the alignment bridge 22 can be instantaneously stopped at the probe center without causing slight vibration, and the alignment operation can be started in a very short time. At this time, the positioning block 27A Right and left fixing means 30A Permanent magnet 30B By each fixing rod 29A Is strongly sucked, so that the alignment bridge 22 is firmly fixed at the probe center and reliably prevents displacement from the probe center.
[0027]
As described above, according to the present embodiment, the alignment bridge 22 is moved by one air cylinder 24 according to the pair of left and right guide rods 23, and the fixing means 30A Fixed by rod 29A Is strongly sucked to fix the alignment bridge 22 at the probe center, so that even one air cylinder 24 as a driving mechanism can smoothly move the alignment bridge 22 according to the guide rod 23. The structure can be simplified and the cost can be reduced. Moreover, according to the present embodiment, the fixing means 30A Permanent magnet 30B The alignment bridge 22 is fixed by the 30B This allows the alignment bridge 22 to be instantaneously fixed at the probe center after being sucked, whereby the alignment operation can be started quickly in a very short time to increase the alignment throughput, and stably, accurately and reliably at the probe center. The alignment operation can be performed, and the probing with high reliability can be performed, thereby improving the reliability of the inspection.
[0028]
According to the present embodiment, the fixing means without the air cylinder 24 is used. 30A Solenoid 30C Of the air cylinder 24 30A Solenoid 30C When the alignment bridge 22 is returned from the probe center to the standby position, the alignment bridge 22 has no air cylinder 24. The fixing means that is to move earlier but does not have the air cylinder 24 30A In this state, the suction force is hardly applied. 29A But fixing means 30A , The alignment bridge 22 can be smoothly returned to the standby position without causing the inclination of the alignment bridge 22, in other words, without causing galling between the connecting block 25 and the linear bush 23 </ b> A.
[0029]
Further, upper and lower tapered surfaces are formed on the alignment bridge 22. 26B With positioning 26A And upper and lower tapered surfaces on the base 12A. 27B Positioning block with 27A The positioning projection 26A And positioning block 27A Abutment surface is free in the horizontal direction and positioning projection 26A And positioning block 27A When attaching the two, the positions of the two 26A and 27A can be easily adjusted.
[0030]
In the above embodiment, the permanent magnet 30B And solenoid 30C Fixing means having 30A Has been described, the permanent magnet in the present invention 30B Has the function of instantly fixing the alignment bridge 22 at the probe center, and the solenoid 30C Is a fixing rod even if the drive source of the alignment bridge 22 is one place 29A The present invention has a function of smoothly moving the alignment bridge 22 along the guide rod 24 without tilting through the 30B And solenoid 30C Have their own effects even if they are used alone. That is, the permanent magnet has an effect that the alignment operation can be started quickly, and the solenoid has an effect that only one drive source is required, and the device is simplified. An electromagnet may be used in place of the permanent magnet.
[0031]
In the above embodiment, a positioning projection is used as a device for fixing the alignment bridge 22 to the probe center. 26A , Positioning block 27A , Fixing rod 29A And fixing means 30A And a case where this fixing device is applied to a probe device using a guide rod 23 and one air cylinder 24 has been described. However, this fixing device is a conventional probe device, that is, a linear guide and 2 The present invention can also be applied to a probe device using a single air cylinder as a driving source. In the above embodiment, the positioning projection is used as the fixing device. 26A And positioning block 27A Has been described, but the fixing means 30A The fixing rod 29A By providing a function as a locking member of the positioning projection 26A And positioning block 27A Can also be omitted.
[0032]
【The invention's effect】
According to the invention described in claim 1 of the present invention, it is possible to provide an alignment device for an optical bridge capable of instantly fixing an imaging means for alignment to a probe center and quickly performing an alignment operation.
[0033]
Further, according to the invention described in claims 2 to 4 of the present invention, it is possible to provide an optical bridge alignment apparatus that can simplify the structure and reduce the cost.
[0034]
Further, according to the invention of claims 5 to 7 of the present invention, the imaging means for alignment can be fixed to the probe center in a short time to increase the throughput, and the structure can be simplified to reduce the cost. And a probe device that can increase the reliability of the test.
[Brief description of the drawings]
FIG. 1 is a side view from the loader chamber side showing an embodiment of the alignment apparatus of the present invention.
FIG. 2 is a perspective view showing a main part of the alignment apparatus shown in FIG.
FIG. 3 is an axial sectional view of a solenoid showing a relationship with a fixing rod and a solenoid when the alignment bridge shown in FIGS. 1 and 2 is at a probe center.
FIG. 4 is a plan view of the back surface side showing the alignment bridge shown in FIGS. 1 and 2;
FIG. 5 is a cutaway perspective view showing a prober chamber of a conventional probe device.
FIG. 6 is a side view showing a main part of an alignment device used in the probe device shown in FIG. 5, as viewed from the loader chamber side.
[Explanation of symbols]
12 Prober room (device body)
16 Main chuck (mounting table)
20 Alignment device
21 Camera (imaging means)
22 Alignment bridge
23 Guide rod
24 Rodless air cylinder (drive mechanism)
26A Positioning protrusion
26B Tapered surface
27A Positioning block
27B Reverse taper surface
29A Fixing rod
30C solenoid

Claims (7)

An alignment bridge on which imaging means for aligning the device to be inspected is mounted; and an alignment bridge movably supporting the alignment bridge between a probe center and a standby position above the mounting table and disposed on a probe device body. A pair of guide members, and a drive mechanism for moving the alignment bridge on at least one of the two guide members in accordance with the guide members, and a probe that adsorbs the alignment bridge at both ends thereof, and a magnet fixed at the center alignment apparatus of an optical bridge, characterized in that provided respectively on the probe device body. A solenoid pair of left and right fixing rod protruding from both ends of the upper Symbol alignment bridge are fitted respectively provided, the solenoid is in the direction of the current, in cooperation with the magnet sucks the fixing rod, or the The alignment device for an optical bridge according to claim 1, wherein a repulsive force for canceling the attraction force of the magnet is provided . When the-alignment bridge returns to the standby position, wherein, characterized in that the repulsive force of the magnetic force on the side of the solenoid without the bridge drive mechanism was set larger than the repulsive force of the magnetic force on the side of the solenoid with the drive mechanism Item 3. An alignment device for an optical bridge according to Item 2. A pair of left and right positioning projections having tapered upper and lower surfaces are projected from both ends of the alignment bridge in parallel with the respective guide rods, and the respective positioning projections abut against each other so that the alignment bridge is held at a probe center. The alignment device for an optical bridge according to claim 3, further comprising a positioning block having an inverted tapered surface for positioning. An alignment bridge mounted with imaging means for moving according to a pair of left and right guide rods between the probe center and the standby position above the mounting table and for aligning the object to be inspected on the mounting table; A drive mechanism disposed on one side of the two guide rods for moving in accordance with the guide rods; and a permanent magnet for adsorbing the alignment bridge at both ends thereof and fixing the alignment bridge at a probe center. Solenoids that are provided on the body and generate repulsion that can offset the attractive force of each permanent magnet are provided integrally with each permanent magnet, and a pair of right and left fixing rods that fit into the solenoids at the probe center are connected to the alignment bridge. Parallel to each of the above guide rods from both ends of Probe apparatus characterized by respectively projecting from. The repulsive force of the magnetic force on the side of the solenoid without the drive mechanism, a probe apparatus according to claim 5, characterized in that set to be larger than the repulsive force of the magnetic force on the side of the solenoid with the drive mechanism. A pair of left and right positioning projections having tapered upper and lower surfaces are projected from both ends of the alignment bridge in parallel with the respective guide rods, and the respective positioning projections abut against each other so that the alignment bridge is held at a probe center. 7. The probe device according to claim 5, further comprising a positioning block having an inverted tapered surface for positioning.

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