JP3658907B2 - Method and apparatus for restarting operation of semiconductor slicing apparatus during wire cutting - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor slicing apparatus that presses and cuts a semiconductor ingot while supplying slurry to a wire, and more particularly to a method and apparatus for resuming operation of a semiconductor slicing apparatus during wire cutting.
[0002]
[Prior art]
As a slicing device for a single crystal ingot, a known inner peripheral slicer for slicing by moving the workpiece b of the single crystal ingot in a direction perpendicular to the axis with respect to the inner peripheral blade, and a wire on the outer peripheral surface as shown in FIG. Rollers b, c, and d each having a fitting groove a (see FIG. 3) formed in a spiral shape are disposed at the apex positions of the inverted triangles, and wires are inserted between the fitting grooves of these rollers b, c, and d. A row e is formed, and the semiconductor ingot h is pressed and the semiconductor ingot is sliced and cut by the lapping action of the abrasive grains while supplying the slurry g containing abrasive grains of the cutting material from the slurry supply nozzle f to the wire rows e ( Wire saw) is used, but the former inner-blade slicer has the advantage that it has less material loss than the latter wire saw and can be sliced and cut with high accuracy. However, due to the structure, the wafers have to be cut out one by one, and there is a weak point that they are not suitable for cutting large-diameter semiconductor ingots because of their low mass productivity. Therefore, in recent years, a wire saw type is being adopted as a slicing apparatus for a large-diameter semiconductor ingot.
[0003]
[Problems to be solved by the invention]
By the way, the wire of the wire saw is made of a high hardness wire rod, such as a special piano wire, which is rich in wear resistance and tension resistance, and the roller is a resin roller having a predetermined hardness to prevent the wire from being damaged. However, due to wear or fatigue of the wire over time, the wire may be cut and entangled with the roller when slicing the semiconductor ingot, or the cut groove may damage the fitting groove on the outer periphery of the roller. In some cases, the cutting of the wafer cannot be continued.
[0004]
In such a case, conventionally, after performing a detaching operation for detaching the ingot of the semiconductor ingot from the wire, the wire is manually or withdrawn, or the roller driving device is manually operated so that the cutting position of one of the rollers is set. Pull out to the outside as appropriate, connect the cut parts together, and then pull out again to a position where the connection part of the wires does not directly participate in the cutting of the semiconductor ingot. The exchange work of exchanging for something was done. Then, after such a wire repair process, the semiconductor ingot is sliced by resuming the semiconductor ingot by resuming the engagement of each notch of the semiconductor ingot corresponding to each row of wires. The recovery work was completed.
[0005]
However, when the time required from the start of the wire restoration to the resumption of cutting of the semiconductor ingot is extremely short, for example, when the cutting of the wire occurs in a place where it is not fitted to the roller, the wire is simply connected between the wires. When the wire repair process takes a long time (1 to 3 hours) except when the process can be completed, the roller that has been thermally expanded due to frictional heat with the roller bearing and the wire is cooled. As a result, the pitch of the wire fitting groove into which the wire is fitted becomes narrow, so that when the cutting of the semiconductor ingot is resumed in this state, an uncorrectable level difference occurs on both the wafer to be cut and the cut surface of the semiconductor ingot. There was a problem.
[0006]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a novel wire slicing type semiconductor slicing device in which the thermal contraction of a roller immediately after cutting a wire is regulated so that the wire can be connected or replaced. It is an object to provide a method and apparatus for connecting or exchanging wires of a semiconductor slicing apparatus.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, a wire fitting groove is formed at a predetermined winding pitch on the outer peripheral surfaces of the rollers arranged in parallel with each other, and the wire wound between the fitting grooves of the rollers is provided on the roller. In the operation method of the semiconductor slicing apparatus, the semiconductor ingot is pressed by reciprocating within a predetermined range by forward / reverse rotation of the wire and pressing the semiconductor ingot while supplying the slurry containing the cutting material to the reciprocating portion of the wire.
A passage for selectively introducing a low-temperature heat exchange medium for suppressing thermal expansion and a high-temperature heat exchange medium for suppressing thermal contraction by a switching valve is formed in advance in the bearing housing and other roller support portions of the respective rollers. Every
During normal ingot cutting, semiconductor ingot slice cutting is performed by forward and reverse rotation of the roller and slurry supply while supplying a low-temperature heat exchange medium that regulates thermal expansion to the passage,
On the other hand, when the wire is cut , the forward / reverse rotation of the roller and the supply of slurry are stopped, and the switching valve is switched to introduce a high-temperature heat exchange medium that regulates thermal shrinkage into the passage, the cut part is connected with a drawer to a position that is not directly used for cutting the semiconductor ingot,
The connection termination after switching the switching valve to introduce a heat exchanging medium of the low temperature to the passage, Installing press cuts the semiconductor ingot to the wire in this state, forward and reverse rotation of the supply and the roller of the slurry It is characterized by restarting.
[0008]
In other words, immediately after the wire is cut, the forward / reverse rotation of the roller is stopped, and the slurry supply is stopped, thereby preventing the entanglement of the wire from getting worse and damaging the roller due to the wire cutting part. By supplying a heat exchange medium that regulates heat shrinkage, such as water or oil, the heat shrinkage of the roller due to the heat shrinkage of the bearing housing is suppressed, and the pitch of the wire fitting grooves is kept constant.
[0009]
Then, the pair of cutting portions of the wire are drawn out and connected to a position where they are not directly involved in the cutting of the semiconductor ingot, and in this state, the cutting of the semiconductor ingot is pressed against the wire to supply the slurry and By resuming forward / reverse rotation of the roller, slice cutting without a step is enabled.
[0010]
According to a second aspect of the present invention, a wire fitting groove is formed at a predetermined winding pitch on the outer peripheral surfaces of rollers arranged in parallel with each other, and the wire wound between the fitting grooves of the rollers is provided on the roller. In a semiconductor slicing apparatus that reciprocates within a predetermined range by forward and reverse rotation of the wire, and presses the semiconductor ingot while supplying slurry containing a cutting material to the reciprocating portion of the wire,
A path for selectively introducing a low-temperature heat exchange medium for suppressing thermal expansion and a high-temperature heat exchange medium for suppressing thermal shrinkage by a switching valve in the bearing housing and other roller support portions of each roller,
Means for determining when the wire is cut based on an output of a refusal sensor that detects thermal displacement of the roller using the end face of the roller as a detected surface;
During normal ingot cutting, a semiconductor ingot slice is cut by forward / reverse rotation and slurry supply by transmitting a forward / reverse rotational driving force to the roller while supplying a low-temperature heat exchange medium that regulates thermal expansion to the passage. ,
At the time when the wire is cut based on the determination result by the determination means, a high-temperature heat exchange medium that stops forward / reverse rotation of the roller and supply of the slurry and switches the switching valve to restrict thermal contraction in the passage is provided. Introducing and connecting a pair of cutting points of the wire to a position not directly used for cutting the semiconductor ingot,
After the connection is completed, the switching valve is switched to introduce the low-temperature heat exchange medium into the passage, and in this state, the notch of the semiconductor ingot is pressed against the wire, and the slurry is supplied and the roller is rotated forward and backward. It is characterized by comprising a controller configured to transmit force and resume forward and reverse rotation.
That is, when the wire is cut, the controller performs switching of the switching valve in accordance with the thermal expansion / contraction of the detection means, so that the thermal contraction of the roller due to the thermal contraction of the bearing housing is maintained in the state immediately after the cutting.
For this reason, if wires are connected and exchanged as in the first aspect of the present invention, the pitch deviation of the wires can be suppressed even when cutting is resumed, and a wafer free from cutting defects can be obtained.
The semiconductor slicing device detects the change in the distance from the detection surface to the detection surface of the roller as a change amount of the thermal expansion / contraction, and detects the change in the controller. It is good to comprise from the non-contact sensor which inputs into.
[0011]
By detecting the thermal expansion / contraction of the roller in a non-contact manner in this way, the reliability of the sensing can be maintained, and correct control for the thermal expansion / contraction of the roller can be performed.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the constituent members described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely described. It is just an example.
[0013]
FIG. 1 is a structural diagram of a semiconductor slicing device according to an embodiment of the present invention, FIG. 2 is a block diagram of a control system for controlling the thermal expansion of a roller, and FIG. 3 is a relationship between a semiconductor ingot cutting invitation and a slurry supply device. The schematic structure which shows is shown.
[0014]
First, the main configuration of the slicing apparatus will be described in detail with reference to FIGS.
A head roller 2 and a tail roller 3 are rotatably supported via a bearing 4 and spaced apart from each other at an upper portion of the main body substrate 1 which is a fixed system. A driving roller 5 is pivotally supported in the lower part in parallel with the head roller 2 and the tail roller 3. The rollers 2, 3 and 5 are formed with fitting grooves 7 on the outer peripheral surface thereof at a predetermined spiral pitch from one end to the other end, and one wire is inserted into the fitting grooves 7 of these rollers 2, 3 and 5. 6 is wound, and the head roller 2 and the tail roller 3 are simultaneously rotated in the same rotational direction via the wire 6.
[0015]
As shown in FIG. 2, the wire 6 cooperates with a slurry containing an abrasive and cuts the semiconductor ingot 12 pressed against the slurry by a lapping action of abrasive grains. It is composed of a rich and hard wire, for example, a special piano wire. Then, both ends of the wire 6 extend outwardly from the head roller 2 and the tail roller 3 and are once guided upward by a fixed pulley 8 and a moving pulley 9 supported by a fixed system, and then another fixed pulley. A constant tension is applied to the wire 6 by the weight of a weight (not shown) which is folded downward again (not shown) and attached to the front end portion and the rear end portion thereof.
[0016]
The traveling of the wire 6 is performed by, for example, a driving device 11 that transmits forward and reverse rotational driving force to the driving roller 5 to reciprocate the predetermined range, and the semiconductor ingot 12 is pressed against the wire 6. 6 is made by a feeding device 13 of the semiconductor ingot 12 arranged above the semiconductor 6.
[0017]
Now, the object of the present invention is to eliminate the pitch deviation of the wire 6 due to the thermal contraction of the rollers 2, 3 and 5 from the time when the wire 6 is cut to the time of resumption, and to suppress the occurrence of a wafer step due to this. There is to do.
[0018]
Therefore, in this embodiment, the head roller 2, the tail roller 3 and the drive roller 5 are directly related to the thermal expansion / contraction of the roller, that is, as shown in FIG. A supply passage 15a and a discharge passage 15b for a heat exchange medium, such as water and oil, are formed in the bearing housing 4a in the bearing portion 4 that is in contact with the heat transfer portion, and the supply passage 15a and the discharge passage 15b are respectively formed. Via a switching valve (two-way switching valve) 16, 17, the supply passage 18a and the discharge passage 18b of the low-temperature heat exchange medium and the supply passage 19a and the discharge passage 19b of the high-temperature heat exchange medium passage are connected in a switchable manner. During normal operation, that is, during normal ingot cutting without causing wire cutting, the slurry is supplied by the slurry nozzle 20 and the supply passages 15a of the rollers 2, 3 and 5 are supplied. The switching valves 16 and 17 are switched to allow the low-temperature heat exchange medium supply passage 18a and the discharge passage 18b to communicate with the discharge passage 15b, and the thermal expansion thereof is restricted. When the wire 6 is cut, the low temperature heat exchange medium supply passage 18a is disconnected from the heat exchange medium supply passage 15a and the discharge passage 15b of each of the rollers 2, 3 and 5 to supply the high temperature heat exchange medium passage. The switching valves 16 and 17 are switched so as to communicate the passage 19a and the discharge passage 19b, and the heat shrinkage of the rollers 2, 3, and 5 is restricted.
[0019]
In this case, in order to correctly perform the switching between the normal time and the abnormal time and correctly set the temperature and flow rate of the heat exchange medium at the time of switching, the switching timing of the switching valves 16 and 17 is accurately determined, It is preferable to accurately detect the temperature of the heat exchange medium to be supplied and set the flow rate accurately.
[0020]
For this reason, in the embodiment of the present invention, as shown in FIG. 1, the end face 21a of the end face plate 21 integral with the rollers 2, 3, and 5 is used as a non-detection face. A distance measuring sensor 22 is attached so that the distance between the end surface 21a can be grasped as thermal expansion or displacement at the time of thermal contraction of each of the rollers 2, 3 and 5, and the output of the distance measuring sensor 22 is sent to a controller (CPU Etc.) and a temperature sensor 24 for detecting the outlet temperature with respect to the discharge passage 18b for the low temperature heat exchange medium as shown in the block diagram of FIG. A temperature sensor 25 for detecting the outlet temperature is provided for the passage 19b. The controller 23 is configured to store the distance S to the end surface 21a of the end surface plate 21 detected when the normal semiconductor ingot 12 is cut as a reference value (for example, 0), and the arithmetic processing unit When the difference on the + side between the reference value and the distance S1 currently detected by the distance measuring sensor 22 exceeds a predetermined value, it is determined that the wire is disconnected, and the reference value S and the current distance measurement are determined. When the negative difference with the distance S1 detected by the sensor 22 is less than a predetermined value, it is determined that the ingot is cut normally. Further, the outlet temperature detected by each of the temperature sensors 24 and 25 is determined. After calculating the heat load of each of the rollers 2, 3, and 5 based on the above, the capacities of the cooling device 26 and the heating device 27 with respect to the heat loads are adjusted, and the flow rate corresponding to the capacities is calculated to calculate the low-temperature heat exchange medium. Supply It has become the supply amount of the supply device 29 of the location 28 and the high temperature of the heat exchange medium so as to adjust, respectively. In this case, when the optical sensor is used for the distance measuring sensor 22, a reflector (reflecting plate) is provided on the end surface 21a. In order to control accuracy and save energy, thermal expansion / heat It is preferable to gradually increase the supply amount and temperature control of the heat exchange medium for shrinkage regulation.
[0021]
Wire repair method according to the present embodiment, during wire cutting, on the basis of the change in the detection value S of the distance measuring sensor 22, the upper Symbol controller 23, the notch of the semiconductor ingot 12 to stop the roller driving device 11 The wire 6 is pulled out and the switching valves 16 and 17 are switched so that a high temperature heat exchange medium is applied to the heat exchange medium passage 15 of the bearing portion 4 of each of the rollers 2, 3 and 5 to restrict thermal contraction. Supplying and regulating the thermal expansion of each of the rollers 2, 3, 5 to the state at the time of cutting the wire, winding the wire 6 manually or by manual control of the roller driving device 11, so that a pair of cut portions of the wire 6 is formed. For example, it is pulled out of the tail roller 3 and connected. Then, after the position of the connecting portion is pulled out to a position that is not directly used for cutting the semiconductor ingot 12, each cut of the semiconductor ingot 12 before the cutting is completed is engaged with each wire row 10 and pressed. After that, in this state, the roller 6 is moved by the roller drive 11 and the slurry is supplied by the slurry supply nozzle 20, while the wire 6 is moved forward and backward by the roller drive 11 to complete the slice cutting of the semiconductor ingot 12. To do.
In this case, when the wire is damaged at a place where the cutting portion does not directly participate in the cutting of the semiconductor ingot 12, it is not particularly necessary to wind the wire 6 for drawing out the cut portion of the wire 6. When the state is bad due to entanglement or the like, the wire 6 is replaced, and the state of the fitting groove 7 of each of the rollers 2, 3, 5 is bad and the cutting of the semiconductor ingot 12 is likely to be adversely affected. After all of the low-temperature / high-temperature heat exchange medium passages 18a, 18b, 19a, 19b are cut off and the rollers are replaced, a high-temperature heat exchange medium is supplied to each of the rollers 2, 3, and 5 immediately after cutting. Return to the state of.
[0022]
When the control is performed by the controller, the roller driving device 11 is automatically stopped and the slurry is supplied to the slurry supply nozzle 20 when the wire cutting is determined by processing the signal from the distance measuring sensor 22. A stop signal is output to a pump (not shown), and when the cutting of the semiconductor ingot is resumed by a manual button or the like, the roller driving device 11 and the slurry supply pump to the slurry supply nozzle are driven so as to drive. If the semiconductor ingot 12 is started at a low speed to press the semiconductor ingot 12 against the wire 6, further labor saving can be promoted.
[0023]
Therefore, according to the method and the apparatus according to the present embodiment, at the time of normal ingot cutting, the low-temperature heat exchange medium that regulates thermal expansion is supplied to the heat exchange medium supply passages 15a and 15b of the rollers 2, 3, and 5. Thus, the pitch of the wire 6 is kept constant, and the slice of the semiconductor ingot 13 during normal operation can be made more accurate and of high quality, and when the wire is cut, the heat shrinkage by the distance measuring sensor 22 is achieved. Accordingly, the switching valves 16 and 17 are switched, that is, a high-temperature heat exchange medium that restricts heat shrinkage is supplied, so that the pitch of the wire 10 is set to be almost the same as that before cutting, and the semiconductor ingot 12 Even if the cutting is resumed, the formation of the step difference of the wafer due to the pitch deviation of the wire 6 is suppressed, which is compared with the wafer obtained by cutting the normal semiconductor ingot 12. It is possible to obtain a comparable-free wafer.
In the description of this embodiment, the reason why the heat exchange medium supply passage 15a and the discharge passage 15b are formed in the bearing housing 4a is that the rollers 2, 3, and 5 are thermally expanded using these as heat sources. . Accordingly, when the flow rate of the heat exchange medium is large and sufficient, the direct heat exchange medium supply passage 15a and the discharge passage 15b are formed in the rollers 2, 3, and 5 without using such a configuration. The switching valves 16 and 17 may be connected to each other.
[0024]
(Example)
FIG. 4 shows an embodiment of a semiconductor slicing device according to the present invention.
As shown in the drawing, the end face 21a of the end face plate 21 integral with each of the rollers 2, 3 and 5 is used as a non-detection face, and the distance between the end face 21a of the substrate 1 is set to the rollers 2, 3 and so on. 5, a distance measuring sensor 22 is attached so that it can be understood as a displacement at the time of thermal expansion or thermal contraction, and an output of the distance measuring sensor 22 is input to the controller 23.
In this case, the bearing portion 4 connects the core body 30 and the inner shaft 31 of the rollers 2, 3 and 5 and fits the inner ring 32 to the inner shaft 31 to arrange the bearings 33 in multiple rows. The outer ring 34 of the bearing 33 was fitted to the inner surface of the cylindrical outer shaft 35, and the outer shaft 35 was fitted to the inner surface of the bearing housing 4a. Then, the inner surface of the bearing housing 4a is recessed radially outward to form a spiral groove 36, which is connected to the two ports 37 and 38 formed in the bearing housing 4a in the spiral groove 36, respectively. A heat exchange medium supply passage 15a and a discharge passage 15b, and the low-temperature heat exchange medium via the switching valves (two-way switching valves) 16 and 17 with respect to the heat exchange medium supply passage 15a and the discharge passage 15b. The supply passage 18a and the discharge passage 18b are connected to the supply passage 19a and the discharge passage 19b of the high-temperature heat exchange medium passage in a switchable manner.
Then, the controller 23 performs control at the time of wire cutting. After the wire 6 is cut, the cutting of the semiconductor ingot is resumed by the above-described method, and the level difference of the obtained wafer is measured. / 4 and the defect rate became 0%.
[0025]
【The invention's effect】
As described above, according to the present invention, it is possible to suppress the formation of a wafer step due to the pitch deviation of the wire even after resuming the cutting of the semiconductor ingot after the wire is cut. An excellent effect is obtained that a wafer having a quality comparable to that of a wafer obtained by cutting an ingot can be obtained.
[Brief description of the drawings]
FIG. 1 is a detailed view showing a main part of an embodiment of a semiconductor slicing device according to the present invention.
FIG. 2 is a perspective view showing an embodiment of a semiconductor slicing device according to the present invention.
FIG. 3 is a block diagram showing an embodiment of a semiconductor slicing device according to the present invention.
FIG. 4 is a detailed cross-sectional view of a main part showing an embodiment of the present invention.
FIG. 5 is a schematic diagram for explaining the configuration of a conventional slicing apparatus.
[Explanation of symbols]
2, 3, 5 Roller 4 Bearing portion 6 Wire 7 Insertion groove 10 Wire row 15a Heat exchange medium supply passage 15b Heat exchange medium discharge passages 16, 17 Switching valve 18a Low temperature heat exchange medium supply passage 18b Low temperature heat Exchange medium discharge passage 19a High-temperature heat exchange medium passage supply passage 19b Low-temperature heat exchange medium discharge passage 22 Distance sensor 23 Controller

Claims (2)

Wire fitting grooves are formed at a predetermined winding pitch on the outer peripheral surfaces of the rollers arranged in parallel to each other, and the wire wound between the fitting grooves of the rollers is moved within a predetermined range by forward and reverse rotation of the rollers. In the operation method of the semiconductor slicing apparatus, the semiconductor ingot is pressed and sliced while supplying the slurry containing the cutting material to the reciprocating portion of the wire.
A passage for selectively introducing a low-temperature heat exchange medium for suppressing thermal expansion and a high-temperature heat exchange medium for suppressing thermal contraction by a switching valve is formed in advance in the bearing housing and other roller support portions of the respective rollers. Every
During normal ingot cutting, semiconductor ingot slice cutting is performed by forward and reverse rotation of the roller and slurry supply while supplying a low-temperature heat exchange medium that regulates thermal expansion to the passage,
On the other hand, when the wire is cut, the forward / reverse rotation of the roller and the supply of slurry are stopped, and the switching valve is switched to introduce a high-temperature heat exchange medium that regulates heat shrinkage into the passage, thereby cutting the pair of wires Pull out and connect the location to a position that is not directly used for cutting the semiconductor ingot,
After the connection is completed, the switching valve is switched to introduce the low-temperature heat exchange medium into the passage, and in this state, the notch of the semiconductor ingot is pressed against the wire, and the supply of the slurry and the forward / reverse rotation of the roller are resumed. A method for restarting operation of a semiconductor slicing apparatus during wire cutting. Wire fitting grooves are formed at a predetermined winding pitch on the outer peripheral surfaces of the rollers arranged in parallel to each other, and the wire wound between the fitting grooves of the rollers is moved within a predetermined range by forward and reverse rotation of the rollers. In a semiconductor slicing device that cuts a slice by pressing a semiconductor ingot while supplying a slurry containing a cutting material to a reciprocating portion of the wire,
A path for selectively introducing a low-temperature heat exchange medium for suppressing thermal expansion and a high-temperature heat exchange medium for suppressing thermal shrinkage by a switching valve in the bearing housing and other roller support portions of each roller,
Means for determining when the wire is cut based on an output of a refusal sensor that detects thermal displacement of the roller using the end surface of the roller as a detected surface;
During normal ingot cutting, the semiconductor ingot slice is cut by forward / reverse rotation and slurry supply by transmitting a forward / reverse rotational driving force to the roller while supplying a low-temperature heat exchange medium that regulates thermal expansion to the passage. ,
At the time when the wire is cut based on the determination result by the determination means, a high-temperature heat exchange medium that stops forward / reverse rotation of the roller and supply of the slurry and switches the switching valve to restrict thermal contraction in the passage is provided. Introducing and connecting a pair of cutting points of the wire to a position not directly used for cutting the semiconductor ingot,
After the connection is completed, the switching valve is switched to introduce the low-temperature heat exchange medium into the passage, and in this state, the notch of the semiconductor ingot is pressed against the wire, and the slurry is supplied and the rollers are rotated forward and backward. A semiconductor slicing device comprising a controller configured to transmit force and resume forward and reverse rotation.

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