KR20200094576A - cutting machine of ingot - Google Patents

Abstract

The present invention relates to an ingot cutting apparatus manufacturing method. An object of the present invention is to manufacture bowed wafers at high yields without need for complicated temperature control or positioning. An ingot (9) is fixed to a holder (10) and cut with a wire saw having wires (5) wound around a plurality of grooved rollers (1, 2) of a predetermined pitch. The ingot (9) is pressed onto the wires (5) and cut into the wafers. The holder (10) is moved along one direction parallel to the axial direction of the grooved rollers (1, 2) until half of the ingot cross section is cut off. Then the holder (10) is moved along the reverse direction, and at this time the other half of the ingot (9) is cut off. A shape of the cut wafers is controlled by movement of the holder (10) so that an appropriate bow effective to reduce a final bow is assigned to the cut wafers.

Description

Manufacturing method of ingot cutting device{cutting machine of ingot}

The present invention cuts the silicon ingot with a wire saw that can freely adjust the bow to be assigned to the wafer.

Is about the method and also about the device for him.

Wafers useful as substrates for semiconductor devices are cut from the ingot. This ingot is a CZ crystal growth method

And the like. After the head and tail are cut from the ingot, the ingot is processed with a crystal surface grinding machine.

After being cut, it is cut into a plurality of wafers having a predetermined thickness. Commonly used cutters have an inner diameter

Although it is a saw, a wire saw using a high-tensile steel wire or the like has been used to cope with the recent increase in wafer size.

Has been used.

Conventional wire saws have a wire wound around a plurality of groove rollers of a predetermined pitch. The wire is released from the reel

Coming, moving on the groove roller along one direction, and winding on the other reel. The wire reciprocates between the two reels.

Can be moved. While the abrasive slurry is supplied to the wire, the ingot is pressed onto the wire. Due to the cutting resistance of the wire, the ingot is well formed by a plurality of wafers having a thickness approximately equal to the pitch at which the wire is wound on the groove roller.

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After the cut wafer is wrapped, chemically etched, and then polished, it is made of a device such as CVD or epitaxy.

It is processed in the early stage. The wafer will be bowed during processing. Bow is adjusted within a certain range

Should be; Otherwise, it is difficult to form a semiconductor having a predetermined structure with high precision.

In order to properly adjust the final bow to be allocated to the wafer, the shape of correcting the deformation during the device manufacturing step

It is preferable to cut the ingot with the wafer to have. Properly adjusted bows can effectively be used for CVD, epitaxy, etc.

It eliminates deformation of the wafer during the process and enables the construction of a semiconductor device of precise design.

For example, Japanese Patent Laid-Open No. 8-323741 describes the displacement of the grooved roller to cut the ingot into an appropriately bowed wafer.

The dragon is started. The bearing part for the groove roller is controlled by the use of friction heat during the rotation of the groove roller or temperature

Is thermally expanded to displace the groove roller along the axial direction.

However, the proposed method does not require precise warming because the axial displacement of the groove roller depends on the thermal expansion of the bearing part.

Degree adjustment is required. Moreover, when a pair of groove rollers are inevitably moved along the axial direction at the same displacement distance

Because of this, the groove roller must be positioned and pre-set with high dimensional accuracy. These precise settings are quite long

need. As a result, the device lacks operating performance, and a properly bowed wafer has a weak yield.

Is obtained.

The present invention provides for the production of a suitably yielded wafer with high yield without the need for difficult temperature control or positioning.

The purpose.

Ingot cutting method according to the present invention, the ingot is wound on a plurality of groove rollers of a predetermined pitch and the slurry is supplied

When pressed onto the ear, hold the ingot along one direction parallel to the axis of the groove roller until half of the ingot section is cut.

Moving the holder to fix and then fix it along the reverse direction while cutting the other half of the ingot

It is characterized by.

The movement distance of the holder is adjusted according to the value corresponding to the expected bow to be assigned to the wafer. Holder's rickshaw

The li can be adjusted in response to the degree of displacement induced by thermal expansion of the groove roller along the axial direction, thereby determining the degree of the bow.

Adjust tightly.

Wire saw device designed for the above purpose is a pair of groove rollers, ingots located parallel to each other on both sides of the ingot

Holder for fixing, lifter for moving the holder with the ingot along the vertical direction, transfer screw inserted into the holder

Lu, the drive motor that applies torque to the transfer screw, and the holder that is moved by the rotation of the transfer screw

The load resistance calculates the movement of the holder in response to the cutting degree of the guide member and the ingot and sends a control signal to the drive motor.

Output to adjust the rotational speed of the conveying screw and adjust the rotational direction of the conveying screw in response to the ingot's cut.

It consists of switching control means. Groove rollers cut a number of sculpted grooves on the surface to

Have The influence of the displacement of the groove roller can be eliminated by the controlled movement of the holder. Thermal expansion for this purpose

A position sensor is provided to detect the displacement of the groove roller caused by the window, and the degree of displacement detected by the position sensor

It is input to the control means for calculating the motion trajectory of the holder to correct the displacement of the groove roller.

As described above, according to the present invention, the ingot is moved reciprocally while cutting the ingot with a wire saw. Wow

Then, by controlling the reciprocating motion of the ingot during cutting without fundamentally changing or complicating the configuration of the saw.

As a result, a suitable bow is easily assigned to the wafer. CVD for wafers that are shaped in this way,

When epitaxy or the like is performed, the final bow is reduced, and a high-grade semiconductor device is manufactured with high yield.

The present invention fundamentally changes the structure of the wire saw, but does not complicate it, and corresponds to the cut degree of the ingot.

By cutting the ingot, the holder holding the ingot along the adjusted direction is moved reciprocally.

Is realized.

As shown in Fig. 1, the wire saw generally has three groove rollers 1-3. One of the groove rollers

It is coupled to the drive motor (4). The wire 5 wound on the groove roller 1-3 is released from the wire reel 6 and then

It is wound on the right wire reel (7). Preferably the tension is applied to the wire 5 by a tensioner 8,

The tensioned wire is moved along one direction or reciprocally on the groove roller 1-3.

The ingot 9 to be cut is fixed to the holder 10 and is located between the groove rollers 1 and 2. While cutting the ingot (9),

The slurry 11 is fed to the wire 5 to facilitate cutting. The slurry 11 is transferred from the slurry reservoir 12.

After being fed to the wire 5 through the feed pipe 13 and the nozzle 14, the slurry 11 is recovered from the fan 15 and then

Return to the slurry reservoir 12. The slurry is cooled by circulation between the slurry reservoir 12 and the heat exchanger 16

do.

2, the ingot is secured to the holder through the graphite plate 17. Holder 10 is an arrow

Can be moved reciprocally along the direction X indicated by and can also be lifted along the vertical direction Z by the lifter 18

Can. The position sensor 19 is provided at a position facing the side surfaces of the groove rollers 1 and 2.

The reciprocating motion of the holder 10 along the direction X is controlled by the control means shown in FIG. 3. The control means is a holder (10)

It has the feed screw 20 inserted. The feed screw 20 is fixed to the drive gear 21 at the end. Drive gear

When the 21 is rotated by the driving force transmitted from the driving motor 22 through the driving gear 23, the holder 10 is transferred

It is moved along the guide 24 by the rotation of the screw 20.

For example, if a servo motor is used as the drive motor 22, the position of the groove rollers 1 and 2 detected by the position sensor 19 is

The signal S 1 and the position signal S2 of the ingot 9 detected by another position sensor 25 are input to the control means 26.

The control means 26 calculates the degree of motion of the holder 10 to compensate for the displacement of the groove rollers 1 and 2 caused by thermal expansion and closes it.

The signal S3 is output to the driving device 27 according to the loop control system. The driving device 27 receives the control signal S4 from the servo motor.

Output to (driving motor 22), the holder 10 is moved within a certain distance according to a predetermined program. The movement of the holder 10 can be controlled by an open loop control system using a stepping motor instead. Can. This room

In the law, the rotation speed and rotation direction of the drive motor 22 are adjusted in response to the degree of cutting of the ingot 9, and the ingot 9 is

It is cut into wafers with a suitable bowed shape.

During cutting, the holder 10 follows one direction until almost half of the cross section of the ingot 9 is cut with the wire 5.

Is moved. After that, the holder 10 is moved along the reverse direction while cutting the other half of the ingot 9. In other words,

The holder 10 is moved along a motion trajectory as shown in FIG. 4. As a result, cut from the ingot (9)

The wafer has a shape that is reversed with respect to the motion trajectory of the holder 10 as shown in FIG. 5. complication

Controlled reciprocation of the ingot 9 coupled with the holder 10 without a wire saw of one structure allows the appropriate bow to be assigned to the wafer

Can be. In addition, the degree of bow can be easily adjusted by changing the movement trajectory of the holder 10.

While cutting the ingot 9, the groove rollers 1 and 2 are heated by friction with the wire 5. The friction heat is the axis of the groove roller

It causes thermal expansion of the groove rollers 1 and 2 along the direction. The displacement of the grooved rollers (1, 2) caused by thermal expansion of the wafer

It has a detrimental effect on form. This deleterious effect detects the displacement of the groove rollers 1 and 2 and the displacement

It is removed by reciprocating the motion trajectory of the holder 10 in response to the teeth.

For example, the actual displacement detected by the position sensor 19 is compared with the preset value of displacement, and the detected value and preset

A control signal corresponding to the difference between the ground values is output to the driving motor 22, and the holder 10 is a groove roller caused by thermal expansion.

(1,2) is moved to a regulated distance that eliminates the displacement.

The properly adjusted bows assigned to the wafers in this way are generated during device manufacturing steps such as CVD and epitaxy.

By reducing the final bow to be produced, a predetermined pattern is processed with high precision in the photolithography step.

It can be transferred to the wiper and the wafer can be kept stable with a vacuum chuck. As a result, high-grade D

The vise can be produced in high yield.

(Example)

Groove rollers 1, 2 with grooves formed at a pitch of 1100 mm on the surface were located on both sides of the ingot 9. Diameter 018mm

The high-tensile steel wire 5 of was wound on the groove rollers 1 and 2. The wire 5 is a new wire 100m / min

It is moved at an average linear speed of 500 m/min according to the reciprocating mode to supply at a speed of. 200mm in diameter

The ingot (9) is cut by a wire saw, and the slurry (11) prepared by mixing the softened GC#600 with the wrapping oil

It was supplied to the wire 5 at a flow rate of 70 L/min.

It took 200 minutes to cut the ingot 9 to a depth of 100 mm corresponding to half the diameter from the beginning of cutting. Cutting this

During the step, the holder 10 was moved to the left in FIG. 2 at an average speed of 025 μm/min.

It took another 200 minutes to cut the other half of the ingot (9). During this cutting step, the holder 10 has an average of 025 μm/min.

The speed was shifted to the right in FIG. 2.

When observing the wafer obtained by this method, the bow was assigned to the wafer with a d value of 50 μm (shown in FIG. 5).

The movement trajectory of the holder 10 was accurately reflected in the bow. While changing the motion trajectory of the holder 10, another ingot

When cut, the d value of the bow changes in the range of 10-100 μm in response to the motion trajectory.

Claims (1)

In a method of cutting an ingot with a wire saw having a wire wound on a plurality of groove rollers of a predetermined pitch: in
Fixing the place to the holder; The ingot is moved along one direction on a plurality of groove rollers or is reciprocated.
Pressing on the wire being moved to; Flat to the axis of the groove roller until half of the cross section of the ingot is cut.
Moving the holder along one direction performed; And reverse while cutting the other half of the ingot.
It consists of the step of moving the holder accordingly, whereby the wafer cut from the ingot is of the holder
A method characterized by having a bowed shape corresponding to a motion trajectory.

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