JP2002018831A - Wire saw cutter and method for slicing semiconductor crystal ingot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire saw cutter capable of efficiently cutting out a slice semiconductor wafer not having a thickness unevenness and having small warp as compared with a semiconductor crystal ingot, and a method for slicing the ingot. SOLUTION: The wire saw cutter comprises a plurality of bearings, a roller supported to the plurality of bearing having wire engaging grooves on an outer peripheral surface and with a plurality of polymer material coating grooves, and a wire engaged with the outer peripheral surface of the roller with the grooves. The roller with the plurality of polymer material coating grooves is temperature regulated to a predetermined temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wire saw cutting apparatus and a method for slicing a semiconductor crystal ingot. More specifically, the present invention relates to a wire saw cutting apparatus and a semiconductor crystal ingot slicing method for cutting a slice semiconductor wafer from a semiconductor crystal ingot using the wire saw cutting apparatus.

[0002]

2. Description of the Related Art Semiconductor crystal wafers are mass-produced as base wafer materials for semiconductor devices.

[0003] The manufacturing procedure of this semiconductor crystal wafer is as follows: first, a semiconductor crystal ingot is manufactured, then the semiconductor crystal ingot is sliced, and then the sliced semiconductor crystal wafer obtained by the slicing is roughly polished. The roughly polished sliced semiconductor crystal wafer obtained by the coarse polishing is mirror-polished, and finally the mirror-polished one is degreased, washed, and dried to be a dried and finished mirror-polished semiconductor crystal wafer. I have.

A method of slicing a semiconductor crystal ingot includes an inner peripheral blade slicing method using an inner peripheral blade obtained by electrodepositing diamond or the like on an inner peripheral surface of a donut-shaped steel plate, a method of slicing a wire and a grinding wheel. There is a wire saw slicing method in which slicing is performed using grains.

[0005] In the conventional slicing operation, the former inner peripheral blade slicing method has been the mainstream, but in recent years, the latter wire saw slicing method has increased. This is because the wire saw slicing method enables a large amount of slicing at one time, and the cutting margin is small, whereby the number of sliced semiconductor crystal wafers can be greatly increased.

FIG. 3 is a perspective view showing a state where a semiconductor crystal ingot is sliced by a conventional wire saw cutting apparatus.

In FIG. 3, 1 is a grooved roller coated with a polymer material used in a conventional wire saw cutting device, 2 is a shaft core, 3 is a polymer material coating layer, 4 is a bearing, 5 is a wire,
Reference numeral 6 denotes an ingot table, and reference numeral 7 denotes a semiconductor crystal ingot.

As can be seen from FIG. 3, in the conventional wire saw cutting apparatus, three conventional polymer material-coated grooved rollers 1 are provided at bearing portions 4 at each vertex of a triangle formed when a wire 5 is hung. It is supported by.

These conventional polymer-coated grooved rollers 1 have a mandrel 2 at the center of the shaft, and the mandrel 2 is coated with a polymer material coating layer 3. Here, the polymer material is rubber, synthetic resin, or the like.

On the outer peripheral surface of the polymer material coating layer 3, a plurality of wire passage grooves are formed at predetermined intervals along the circumferential direction. The interval between the plurality of wire passage grooves is equal to the thickness of the sliced semiconductor crystal wafer.

The wire 5 is sent out from a bobbin (not shown), wound around three grooved rollers 1 via a tension adjusting roller (not shown), and then wound up on a winding bobbin (not shown).

As can be seen from FIG. 2, an ingot table 6 is placed below the lower two polymer-coated grooved rollers 1, and a semiconductor crystal ingot 7 is placed on the ingot table 6. I have.

Next, a procedure for slicing a semiconductor crystal ingot by the conventional wire saw cutting apparatus shown in FIG. 3 will be described.

First, the power of the conventional wire saw cutting device is turned on, and the wire 5 is run.

Next, although not shown, the semiconductor crystal ingot 7 mounted on the ingot table 6 and the traveling wire 5
Is supplied to the vicinity of the intersection with the polishing liquid containing abrasive grains.

Next, in this state, the semiconductor crystal ingot 7
Is pressed against the wire 5, a plurality of sliced semiconductor crystal wafers can be cut out from the semiconductor crystal ingot 7.

As the specific material of the polymer material coating layer 3 of the polymer material coating groove forming roller 1, polyurethane, polyethylene, or the like, which is excellent in workability and inexpensiveness, is often used.

Now, when a semiconductor crystal ingot is sliced by a conventional wire saw cutting device equipped with a polymer material coated grooved roller 1 formed by coating a polymer material coated layer 3 of polyurethane, polyethylene, etc. The temperature of the polyurethane or polyethylene of the coating layer 3 rises due to friction with the wire 5 and heat conduction of frictional heat of the bearing portion 4, and as a result, elongation occurs in the longitudinal direction. The temperature rise depends on various slice conditions, but the temperature rise when a standard slice for several hours is performed is about 10 ° C.

On the other hand, the elongation of the polymer material-coated grooving roller 1 formed by coating the high-density polyethylene of the polyethylene as the polymer material coating layer 3 with the temperature rise is approximately 0.1%.
01% / ° C.

Therefore, when the temperature rises by 10 ° C., the elongation of the high-density polyethylene coating layer 3 of the polymer material-coated grooved roller 1 formed of high-density polyethylene is 0.1%. For example, the high-density polyethylene coating layer 3 of the high-density polyethylene coating grooving roller 1 having a length of 200 mm at room temperature extends 200 μm.

For this reason, in the conventional wire saw cutting apparatus provided with the high-density polyethylene coating grooved roller 1 formed by coating the high-density polyethylene coating layer 3, when the semiconductor crystal ingot is sliced, the high-density polyethylene coating layer 3 is heated. It expands and contracts due to fluctuations. When the high-density polyethylene coating layer 3 expands and contracts due to temperature fluctuations in this manner, the sliced semiconductor wafer obtained by slicing will have uneven thickness or a warp defect.

Conventionally, the following method has been employed as a measure for suppressing the elongation generated as the temperature of the polymer material coating layer 3 of the polymer material-coated grooved roller 1 rises or as a measure for alleviating the influence of the elongation. Had been

(1) Method of Managing Temperature of Polishing Solution Containing Abrasive Grains As described above, a conventional wire saw cutting apparatus provided with a polymer material coating grooved roller 1 formed by coating a polymer material coating layer 3 is used. When the semiconductor crystal ingot is sliced, the temperature of the polymer material coating layer 3 of the polymer material coating groove forming roller 1 rises as the slicing operation time of the semiconductor crystal ingot elapses.

Therefore, a first countermeasure method is to gradually lower the temperature of the polishing liquid containing abrasive grains to be supplied to the periphery of the slicing portion with the lapse of the slicing operation time, whereby the temperature of the polymer material coating layer 3 is reduced. To cool.

(2) Warm-up operation of the polymer material coating groove forming roller The second countermeasure method is to previously operate the conventional wire saw cutting device for a long time in a warm-up operation to stabilize the temperature of the polymer material coating layer 3 at a high temperature and stabilize it. This is a method in which the slice operation of the semiconductor crystal ingot is started after the high temperature saturation becomes stable.

[0026]

However, the above conventional measures have the following drawbacks.

(1) Method for Managing the Temperature of Polishing Liquid Containing Abrasive Particles This method is easily affected by the flow rate of the polishing liquid containing abrasive particles, and effectively suppresses heat conduction from the bearing 4. Can not do. For this reason, in this method, the variation in the heat distribution of the polymer material coating layer 3 of the polymer material coating groove forming roller 1 becomes large, and as a result, a sliced semiconductor wafer obtained by slicing has many irregular thickness defects and warpage defects. There was a difficulty to do.

(2) Warm-up operation of the polymer-coated grooved roller In the second countermeasure method, the conventional wire saw cutting device saturates both the temperature rise due to friction with the wire 5 and the temperature rise due to heat conduction from the bearing 4. Since the warm-up operation is performed until the temperature becomes stable, useless man-hours and useless energy are consumed. Further, since the high-temperature stabilization is performed, thermal deterioration of the polymer material coating layer 3 is promoted.

The present invention has been made in view of such a point, and an object of the present invention is to solve the above-mentioned disadvantages of the prior art, and to have less thickness irregularity and extremely small warpage than a semiconductor crystal ingot. An object of the present invention is to provide a wire saw cutting device and a semiconductor crystal ingot slicing method capable of efficiently cutting a sliced semiconductor wafer.

[0030]

The gist of the present invention is that a plurality of bearings and a plurality of heights supported by the plurality of bearings and provided with a wire groove on the outer peripheral surface. In a wire saw cutting device including a polymer material-coated grooved roller and a wire wound on the outer peripheral surface of the polymer material-coated grooved roller, the plurality of polymer material-coated grooved rollers are fixed. The wire saw cutting device is characterized in that it is configured to adjust the temperature to the temperature.

In the present invention, the shafts of the plurality of polymer material-coated grooved rollers are formed of a hollow shaft core, and an internal heater and a thermocouple are inserted into the hollow of the hollow shaft core. Preferably, the internal heater and the thermocouple are electrically connected to a temperature controller.

In the present invention, the thermocouple is bent at a middle portion of the hollow shaft core in a direction perpendicular to the outer peripheral side of the polymer-coated grooved roller, and the tip thereof is at the height of the polymer-coated grooved roller. It is preferably inserted so as to reach the intermediate thickness portion of the molecular material coating layer.

In the present invention, the temperature of the polymer-coated grooved roller is adjusted via an internal heater and a thermocouple inserted into the hollow of the hollow shaft core of the polymer-coated grooved roller. preferable.

In the present invention, the adjusting temperature of the polymer-coated grooved roller is set to a temperature slightly higher than the saturation rise temperature when the polymer-coated grooved roller is warmed up, and the temperature of the supplied polishing liquid is adjusted. Preferably, the temperature is adjusted to a temperature lower than the adjustment temperature of the polymer material coated grooved roller.

In the present invention, the control temperature of the polymer-coated grooved roller is more preferably 35.degree. C., and the more preferable control temperature of the polishing liquid is 23.degree.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a wire saw cutting apparatus and a semiconductor crystal ingot slicing method according to the present invention will be described with reference to the drawings.

(One Embodiment of the Wire Saw Cutting Apparatus of the Present Invention) First, one embodiment of the wire saw cutting apparatus of the present invention will be described.

FIG. 1 is an explanatory vertical cross-sectional view of a partly omitted groove forming roller used in a wire saw cutting apparatus according to one embodiment of the present invention.

In FIG. 1, reference numeral 4 denotes a bearing, 10 denotes a grooved roller coated with a polymer material according to an embodiment of the present invention, 11 denotes a hollow shaft core, 12 denotes a polymer material coating layer, 13 denotes a wire passage groove,
14 is a thermocouple insertion hole, 15 is an internal heater, and 16 is a thermocouple.

As can be seen from FIG. 1, the polymer material-coated grooving roller 10 used in one embodiment of the wire saw cutting device of the present invention has a hollow shaft core 11 at the center of its shaft. It is supported by the bearing 4 of the body 11.

The outer periphery of the hollow shaft core 11 is coated with a polymer material coating layer 12 made of high-density polyethylene.
A plurality of wire passage grooves 13 along the circumferential direction are formed on the outer peripheral surface of the polymer material coating layer 12 at predetermined intervals. The interval between the plurality of wire passage grooves 13 is equal to the thickness of the sliced semiconductor crystal wafer.

The inside of the hollow shaft core 11 has an internal heater 1
5 and thermocouple 16 are inserted. The length of the internal heater 15 is substantially the same as the entire length of the polymer material coated grooved roller 10.

The distal end of the thermocouple 16 inserted into the hollow of the hollow shaft core 11 has an opening along the direction perpendicular to the axis center of the hollow shaft core 11 to the intermediate thickness portion of the polymer material coating layer 12. Into the thermocouple insertion hole 14. Thereby, the thermocouple 16 can accurately detect the temperature of the intermediate thickness portion of the polymer material coating layer 12.

On the other hand, although not shown, the other end of the thermocouple 16 is electrically connected to a temperature controller via a universal joint.

Although not shown, the wire is sent out from a bobbin, wound around a triangularly arranged polymer material-coated grooved roller 10 shown in FIG. 1 via a tension adjusting roller, and then wound around a winding bobbin. Is to be taken.

An ingot table is placed below the lower two polymer-coated grooved rollers 10 among the three polymer-coated grooved rollers 10 arranged in a triangle. A semiconductor crystal ingot is mounted on the ingot table.

Next, a procedure for slicing a semiconductor crystal ingot by the wire saw cutting apparatus according to one embodiment of the present invention will be described.

First, the power of the wire saw cutting device according to one embodiment of the present invention is turned on, and the wire is run.

Next, a polishing liquid containing abrasive grains is supplied to the vicinity of the intersection of the traveling wire with the semiconductor crystal ingot placed on the ingot table.

Next, when the semiconductor crystal ingot is pressed against the wire in this state, a plurality of sliced semiconductor crystal wafers can be cut out of the semiconductor crystal ingot by a lapping action.

Next, a slicing experiment was performed to cut a sliced semiconductor wafer from a semiconductor crystal ingot using a conventional wire saw cutting device and the wire saw cutting device of one embodiment of the present invention.

Comparative Example 1 First, a slicing experiment of a semiconductor crystal ingot using a conventional wire saw cutting apparatus was performed under the following conditions.

A. Semiconductor Crystal Ingot A GaAs single crystal ingot having a diameter of 100 mm and a length of 200 mm was prepared.

B. Warm-up operation of the conventional wire saw cutting device The warm-up operation of the conventional wire saw cutting device was not performed.

C. Control of Temperature Control of Polishing Liquid Temperature control of the polishing liquid containing abrasive grains supplied to the periphery of the slice location was not performed.

FIG. 2 shows a temperature change of the polymer material coated grooved roller during the slicing operation of the semiconductor crystal ingot.

As can be seen from FIG. 1, the temperature of the polymer-coated grooving roller before starting the slicing operation was room temperature, but the temperature of the polymer-coated grooving roller which continued the slicing operation rose by 9 ° C. .

As described above, the slice G sliced when the temperature of the polymer material-coated grooved roller rises by 9 ° C.
The dimensions of the aAs wafer were checked. As a result, the thickness unevenness of the sliced GaAs wafer was 10 μm or more, and the warpage was as large as 10 μm or more.

Comparative Example 2 Next, a slicing experiment of a semiconductor crystal ingot using a conventional wire saw cutting apparatus was performed under the following conditions.

A. Semiconductor Crystal Ingot A GaAs single crystal ingot having a diameter of 100 mm and a length of 200 mm was prepared.

B. Warm-up operation of the conventional wire saw cutting device The conventional wire saw cutting device performed a warm-up operation for 3 hours before slicing. The temperature of the polymer-coated grooved roller was stabilized at 23 ° C. by the warm-up operation for 3 hours.

C. Temperature control of polishing liquid 23 polishing liquid containing abrasive particles to be supplied around the slice location
The temperature was adjusted to ° C.

FIG. 2 shows a change in temperature of the polymer-coated grooved roller during the slicing operation of the semiconductor crystal ingot.

As can be seen from FIG. 1, the temperature of the polymer-coated grooving roller before starting the slicing operation was stable at 23 ° C. due to the warm-up operation. As the temperature goes on, the temperature of the polymer-coated grooving roller gradually rises and finally reaches 3 ° C.
The temperature rose.

As described above, the slice G sliced when the temperature of the polymer material-coated grooving roller rises by 3 ° C.
The dimensions of the aAs wafer were checked. As a result, the thickness unevenness of the sliced GaAs wafer was 6 μm or more, and the warpage was 7 μm.

Example 1 Next, Example 1 of a method for slicing a semiconductor crystal ingot using a wire saw cutting apparatus according to an example of the present invention was performed under the following conditions.

A. Semiconductor Crystal Ingot A GaAs single crystal ingot having a diameter of 100 mm and a length of 200 mm was prepared.

B. Warm-up operation of the wire saw cutting device of one embodiment of the present invention No warm-up operation of the wire saw cutting device of one embodiment of the present invention was performed.

C. Temperature control of polishing liquid 23 polishing liquid containing abrasive particles to be supplied around the slice location
The temperature was adjusted to ° C.

D. Temperature control of the polymer-coated grooving roller Before starting the slicing operation, the temperature of the polymer-coated grooving roller 10 is controlled by the internal heater
The temperature was adjusted to 35 ° C. by simply energizing the substrate. The temperature of the polymer material-coated grooved roller 10 was stabilized at 35 ° C. one hour after the start of energization to the internal heater 15.

FIG. 2 shows the temperature change of the polymer material coated groove forming roller during the slicing operation of the semiconductor crystal ingot.

As can be seen from FIG. 1, the temperature of the polymer-coated grooved roller 10 before the slicing operation is started is stabilized at 35 ° C. by energizing the internal heater 15.

When the slicing operation is started, the polymer material-coated grooving roller 10 temporarily drops slightly from 35 ° C. because the polishing liquid at 23 ° C. is applied thereto. And the cooling of the polishing liquid at 23 ° C. is substantially balanced. As a result, the temperature of the polymer-coated grooving roller 10 is stabilized at 35 ° C.

As described above, since the temperature of the polymer material coated groove forming roller is stabilized at 35 ° C., the slicing operation is also stabilized.

The thickness unevenness of the sliced GaAs wafer is remarkably small at 3 μm or less, and the warpage is 3 μm.
m or less.

[0076]

According to the wire saw cutting apparatus and the semiconductor crystal ingot slicing method of the present invention, it is possible to efficiently cut a sliced semiconductor wafer having less thickness unevenness and extremely small warpage than the semiconductor crystal ingot. Yes, industrially useful.

[Brief description of the drawings]

FIG. 1 is an explanatory vertical cross-sectional view partially showing a polymer material-coated grooved roller used in a wire saw cutting apparatus according to an embodiment of the present invention.

FIG. 2 shows a temperature change of a polymer material-coated grooved roller during a slicing operation of a semiconductor crystal ingot.

FIG. 3 is a perspective view of a main part showing a state where a semiconductor crystal ingot is sliced by a conventional wire saw cutting device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 polymer material coated grooved roller 2 used in conventional wire saw cutting device 2 shaft core 3, 12 polymer material coated layer 4 bearing part 5 wire 6 ingot table 7 semiconductor crystal ingot 10 for wire saw cutting device of one embodiment Polymer coated grooved roller 11 hollow shaft core 13 wire passage groove 14 thermocouple insertion hole 15 internal heater 16 thermocouple

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3C058 AA05 AA14 AA16 AC01 BA08 CB01 DA03 DA17 3C069 AA01 BA06 BB03 BB04 BC01 CA04 EA01 EA02 3J103 AA02 AA13 AA63 BA03 DA05 FA18 GA52 HA03 HA41

Claims (7)

[Claims] 1. A plurality of bearing portions, a plurality of polymer material-coated grooving rollers supported by the plurality of bearing portions and provided with a wire hooking groove on an outer peripheral surface; A wire saw cutting device having a wire wound on the outer peripheral surface of the polymer material-coated grooved roller, wherein the plurality of polymer material-coated grooved rollers are configured to adjust the temperature to a constant temperature. Characteristic wire saw cutting device. 2. A shaft core of a plurality of polymer material-coated grooved rollers is formed of a hollow shaft core, and an internal heater and a thermocouple are inserted into a hollow of the hollow shaft core. The wire saw cutting device according to claim 1, wherein the heater and the thermocouple are electrically connected to a temperature controller. 3. A thermocouple is bent in a direction perpendicular to an outer peripheral side of a polymer material coated grooved roller at an intermediate portion of a hollow shaft core,
3. The wire saw cutting device according to claim 2, wherein the tip is inserted so as to reach an intermediate thickness of a polymer material coating layer of the polymer material coating groove forming roller. 4. A method in which a wire hung on an outer peripheral surface of a plurality of polymer material-coated grooved rollers is pressed against a semiconductor crystal ingot, and the polishing liquid containing abrasive grains is supplied to the periphery of the wire pressed portion while supplying the polishing liquid. A semiconductor crystal ingot slicing method for slicing a semiconductor crystal ingot and cutting a slice semiconductor wafer, wherein the temperature of the polymer material coated grooved roller is adjusted to a constant temperature, wherein the semiconductor crystal ingot is sliced. Method. 5. The method of controlling the temperature of the polymer-coated grooving roller via an internal heater and a thermocouple inserted into the hollow of the hollow shaft core of the polymer-coated grooving roller. The method for slicing a semiconductor crystal ingot according to claim 4. 6. The control temperature of the polymer-coated grooving roller is set to a temperature slightly higher than the saturation rise temperature when the polymer-coated grooving roller is warmed up.
5. The method of slicing a semiconductor crystal ingot according to claim 4, wherein the temperature of the polishing liquid to be supplied is adjusted to a temperature lower than the adjustment temperature of the polymer material coated groove forming roller. 7. The method of slicing a semiconductor crystal ingot according to claim 4, wherein the control temperature of the polymer-coated grooved roller is 35 ° C., and the control temperature of the polishing liquid temperature is 23 ° C.