TWI843233B - Multi-wire cutting method and device - Google Patents

Abstract

The present invention provides a multi-wire cutting method and device, belonging to the field of semiconductor technology. The multi-wire cutting device includes: an attack workbench; a crystal rod fixing structure arranged on the attack workbench, the crystal rod fixing structure fixing the crystal rod to be cut; a cutting structure arranged above the attack workbench, including at least two wire rollers, and a plurality of cutting wires wound around the at least two wire rollers; a linear slide mechanism located between the attack workbench and the crystal rod fixing structure, capable of horizontal displacement, and after the linear slide mechanism moves, the horizontal position of the feed shaft of the attack workbench can be changed; and a movement control structure, used to control the linear slide mechanism to perform horizontal displacement according to the cutting compensation amount. The present invention can reduce the variation of the morphology of the cut silicon wafers, thereby improving the quality of the cut silicon wafers.

Description

Multi-wire cutting method and device

The present invention belongs to the field of semiconductor technology, and in particular to a multi-wire cutting method and device.

The main silicon wafer processing technology is multi-wire mortar cutting, which has a high cutting effect and is therefore widely used. The principle is that the cutting wire passes through a set of groove wheels to form a wire mesh with different spacings, and the high-speed reciprocating motion of the cutting wire is used to bring the abrasive into the processing area of the material to be cut for cutting, while the workpiece to be cut is fed vertically by the lifting of the worktable, so that the workpiece is cut into several thin slices of the required size and shape at the same time.

The technical problem to be solved by the present invention is to provide a multi-wire cutting method and device, which can reduce the variation of the morphology of the cut silicon wafers, thereby improving the quality of the cut silicon wafers.

To solve the above technical problems, the embodiment of the present invention provides a technical solution as follows: The embodiment of the present invention provides a multi-wire cutting device, comprising: An attack workbench; A crystal rod fixing structure arranged on the attack workbench, the crystal rod fixing structure fixing the crystal rod to be cut; A cutting structure arranged above the attack workbench, comprising at least two wire rollers, and a plurality of cutting wires wound around the at least two wire rollers; A linear slide mechanism located between the attack workbench and the crystal rod fixing structure, capable of horizontal displacement, and after the linear slide mechanism moves, the horizontal position of the feed shaft of the attack workbench can be changed; A movement control structure, used to control the linear slide mechanism to perform horizontal displacement according to the cutting compensation amount.

In some embodiments, the device further includes: A cutting compensation amount acquisition mechanism, which is used to cut N test crystal rods using the multi-wire cutting device with a fixed position of the linear slide mechanism to obtain multiple silicon wafers, where N is a positive integer; collect the morphological changes of the multiple silicon wafers at different cutting positions; and determine the cutting compensation amount of each cutting position according to the morphological change.

In some embodiments, the cutting compensation amount at each cutting position is zero minus A, where A is the maximum value, minimum value or average value of multiple morphological changes of the multiple silicon wafers at the cutting position.

In some embodiments, N is 3-5.

In some embodiments, during the cutting process, the movement speed of the cutting wire is 500-1200 m/min.

In some embodiments, the cutting structure includes two groups of wire rollers that are spaced a first preset distance along a first direction and arranged side by side, and each group of wire rollers includes two wire rollers that are spaced a preset distance along a second direction. The first direction is a direction perpendicular to the extension direction of the multiple cutting lines, and the second direction is a direction perpendicular to the first direction.

Some embodiments further include a cooling structure for cooling the cutting line, the cooling structure including nozzles disposed on two opposite sides of the crystal rod fixing structure along the second direction, and the nozzles are connected to a cooling medium storage portion through a pipeline.

The embodiment of the present invention also provides a multi-wire cutting method, which is applied to the multi-wire cutting device as described above, and the method includes: When the attack workbench moves, the movement control structure controls the linear slide mechanism to perform horizontal displacement according to the cutting compensation amount, thereby changing the horizontal position of the feed shaft of the attack workbench.

In some embodiments, the method further includes the step of obtaining a cutting compensation amount, and obtaining the cutting compensation amount includes: Using the multi-wire cutting device with a fixed position of the linear slide mechanism to cut N test crystal rods to obtain multiple silicon wafers, where N is a positive integer; collecting the morphological changes of the multiple silicon wafers at different cutting positions; and determining the cutting compensation amount of each cutting position according to the morphological change amount.

In some embodiments, the cutting compensation amount at each cutting position is zero minus A, where A is the maximum value, minimum value or average value of multiple morphological changes of the multiple silicon wafers at the cutting position.

The embodiments of the present invention have the following beneficial effects: In the above scheme, when cutting the crystal rod, the linear slide mechanism is controlled to move horizontally according to the cutting compensation amount, and the horizontal position of the feed axis of the impact worktable is changed, thereby reducing the amount of change in the morphology of the silicon wafer, thereby improving the quality of the cut silicon wafer.

In order to help you understand the technical features, contents and advantages of the present invention and the effects it can achieve, the present invention is described in detail as follows with the accompanying drawings and appendices in the form of embodiments. The drawings used therein are only for illustration and auxiliary description, and may not be the true proportions and precise configurations after the implementation of the present invention. Therefore, the proportions and configurations of the attached drawings should not be interpreted to limit the scope of application of the present invention in actual implementation.

In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

During the multi-wire cutting process, the wire reciprocates at high speed, and the processing table slowly descends to allow the silicon rod to contact the wire for cutting. Currently, the multi-wire cutting machine fixes the crystal rod on the attacking workbench, and the multi-wire cutting process is performed by descending the processing table while the horizontal position remains unchanged. In addition to the change in cutting capacity, multi-wire cutting is also affected by heat. The change in cutting capacity is mainly due to the recycling of mortar. Therefore, from the beginning to the end of cutting, the wear or damage of abrasive cutting will affect the cutting capacity. The heat is mainly generated by the rotation of the drive device and the mortar cutting. Although the machine is designed with a cooling device to take away the heat generated by the drive device and the heat generated by the cutting material in the mortar, it cannot take away all the heat. Therefore, excluding the factors that affect the morphology of the silicon wafer when the hardware device is damaged, the remaining main factors are the change in cutting capacity and the thermal expansion effect that affect the morphology of the silicon wafer. At present, the morphology variation is mainly stabilized by changing the descending speed of the worktable and the use conditions of the steel wire, and then the morphology variation is corrected by changing the mortar temperature, the steel wire guide shaft temperature or the processing table temperature parameters, but the effect is not ideal.

The embodiment of the present invention provides a multi-wire cutting method and device, which can reduce the variation of the morphology of the cut silicon wafers, thereby improving the quality of the cut silicon wafers.

The embodiment of the present invention provides a multi-wire cutting device, as shown in Figures 1 and 2, comprising: an attack workbench 01; a crystal rod fixing structure 03 arranged on the attack workbench 01, the crystal rod fixing structure 03 fixing the crystal rod 04 to be cut; a cutting structure 05 arranged above the attack workbench, comprising at least two wire rollers, and a plurality of cutting wires wound around the at least two wire rollers; a linear slide mechanism 02 located between the attack workbench 01 and the crystal rod fixing structure 03, capable of horizontal displacement, and after the linear slide mechanism 02 moves, the horizontal position of the feed shaft of the attack workbench can be changed; a movement control structure 06, used to control the linear slide mechanism 02 to perform horizontal displacement according to the cutting compensation amount.

In this embodiment, when the crystal rod is cut, the linear slide mechanism is controlled to perform horizontal displacement according to the cutting compensation amount, and the horizontal position of the feed axis of the impact worktable is changed, thereby reducing the variation of the silicon wafer morphology and improving the quality of the cut silicon wafer.

A crystal rod fixing structure 03 is installed under the attack workbench 01 to fix the crystal rod under the attack workbench 01. The linear slide mechanism 02 is integrated under the vertical slide inside the attack workbench 01. The linear slide mechanism 02 can control the horizontal position of the vertical slide and move the normal vertical position.

In this embodiment, a linear slide mechanism 02 is added between the attack workbench 01 and the crystal rod 04. When the attack workbench 01 moves to different cutting positions, the movement control structure 06 controls the linear slide mechanism 02 to perform horizontal displacement according to the cutting compensation amount corresponding to the cutting position. For example, when it moves to cutting position 1, it performs horizontal displacement according to the cutting compensation amount corresponding to cutting position 1; when it moves to cutting position 2, it performs horizontal displacement according to the cutting compensation amount corresponding to cutting position 2, and so on.

In some embodiments, the device further includes: A cutting compensation amount acquisition mechanism, which is used to cut N test crystal rods using the multi-wire cutting device with a fixed position of the linear slide mechanism to obtain multiple silicon wafers, where N is a positive integer; collect the morphological changes of the multiple silicon wafers at different cutting positions; and determine the cutting compensation amount of each cutting position according to the morphological change.

The value of N can be set according to actual production conditions, for example, the value of N can be 3-5.

As the production process continues, the hardware parameters of the multi-wire cutting device will continue to change. In order to ensure the timeliness and accuracy of the cutting compensation, the cutting compensation corresponding to each cutting position can be obtained once every preset cycle, for example, once every 24 hours.

Among them, the cutting position refers to the different positions of the attack workbench in the cutting direction. For example, the cutting path of the attack workbench in the cutting process can be divided into multiple cutting positions. As shown in Figure 3, the cutting path of the attack workbench can be about 300 mm. At each cutting position, the morphology of the silicon wafer obtained after cutting can be measured. Among them, Block1 represents the morphology curve of silicon wafer 1, Block2 represents the morphology curve of silicon wafer 2, and Block3 represents the morphology curve of silicon wafer 3. It can be seen that before the linear slide mechanism 02 is used for cutting compensation, the morphology change of the silicon wafer is large, which is not conducive to the quality of the silicon wafer.

In some embodiments, the cutting compensation amount at each cutting position is zero minus A, where A is the maximum value, minimum value or average value of multiple morphological changes of the multiple silicon wafers at the cutting position.

In a specific example, as shown in FIG4 , the average morphology variation curves of multiple silicon wafers are calculated, and the average morphology variation curve is subtracted from zero to obtain the cutting compensation curve, which indicates the cutting compensation corresponding to each cutting position. For example, at the cutting position of 50 mm (that is, after the attack workbench moves 50 mm in the cutting direction from the initial position, wherein the cutting line just touches the crystal rod when the attack workbench is at the initial position), the average morphology variation of multiple silicon wafers is 4 um, and the corresponding cutting compensation is -4 um; at the cutting position of 100 mm, the average morphology variation of multiple silicon wafers is 4 um, and the corresponding cutting compensation is -4 um.

When cutting, the mobile control structure 06 controls the linear slide mechanism 02 to perform horizontal displacement according to the cutting compensation amount. Specifically, the left side of the machine is the fixed side, the left side of the cutting compensation amount is positive and the right side is negative. The position of the linear slide mechanism is adjusted in the direction corresponding to the numerical value of the cutting compensation amount. The adjustment amount is in um, which can improve the morphology of the silicon wafer. The improved silicon wafer morphology is shown in Figure 5. It can be seen that the morphology uniformity of the silicon wafer is improved, which can improve the quality of the cut silicon wafer.

In this embodiment, after cutting is completed, the morphology of the silicon wafer obtained after cutting can be measured to determine whether the morphology uniformity of the silicon wafer is improved. If it is not significantly improved, the morphology data of the silicon wafer can be fed back to the motion control structure 06, and the motion control structure 06 can readjust the cutting compensation amount.

In some embodiments, in order to ensure the uniformity of the morphology of the silicon wafer, the movement speed of the cutting line during the cutting process may be 500-1200 m/min, but the present invention is not limited thereto.

In some embodiments, the cutting structure includes two groups of wire rollers that are spaced a first preset distance along a first direction and arranged side by side, and each group of wire rollers includes two wire rollers that are spaced a preset distance along a second direction. The first direction is a direction perpendicular to the extension direction of the multiple cutting lines, and the second direction is a direction perpendicular to the first direction.

In a specific example, the cutting structure may include four wire rollers, each of which has a plurality of cutting wire accommodating grooves, and the distribution of the cutting wire accommodating grooves on the four wire rollers is the same, so that the multiple cutting wires are arranged in parallel, and the distance between two adjacent cutting wires is set according to the required thickness of the silicon wafer. The cutting wire is wound around the wire roller to form two layers of cutting wires in the second direction. The cutting wire is wound around the distance between the two adjacent wire rollers in the second direction, thereby providing sufficient moving space for the crystal rod fixing structure to move in the second direction.

In some embodiments, the multi-wire cutting device further includes a cooling structure for cooling the cutting wire, the cooling structure including nozzles disposed on two opposite sides of the crystal rod fixing structure along the second direction, the nozzles being connected to a cooling medium storage portion through a pipeline. The nozzles spray the cooling medium onto the cutting wire to cool it down, thereby preventing the temperature of the cutting wire from being too high during the cutting process and affecting the cutting quality.

The cooling medium can be mortar or other cooling liquids, which are not limited here. A switch valve for controlling the flow rate of the cooling medium is also provided on the pipeline, and the switch valve can be an electromagnetic valve, but is not limited thereto.

The embodiment of the present invention also provides a multi-wire cutting method, which is applied to the multi-wire cutting device as described above, as shown in FIG6, and the method includes: Step 102: When the attack worktable moves, the movement control structure controls the linear slide mechanism to perform horizontal displacement according to the cutting compensation amount, thereby changing the horizontal position of the feed shaft of the attack worktable.

In some embodiments, the method further includes step 101: obtaining a cutting compensation amount, and obtaining the cutting compensation amount includes: Using the multi-wire cutting device with a fixed position of the linear slide mechanism to cut N test crystal rods to obtain multiple silicon wafers, where N is a positive integer; collecting the morphological changes of the multiple silicon wafers at different cutting positions; and determining the cutting compensation amount of each cutting position according to the morphological change amount.

In this embodiment, when the crystal rod is cut, the linear slide mechanism is controlled to perform horizontal displacement according to the cutting compensation amount, and the horizontal position of the feed axis of the impact worktable is changed, thereby reducing the variation of the silicon wafer morphology and improving the quality of the cut silicon wafer.

In this embodiment, a linear slide mechanism 02 is added between the attack workbench 01 and the crystal rod 04. When the attack workbench 01 moves to different cutting positions, the movement control structure 06 controls the linear slide mechanism 02 to perform horizontal displacement according to the cutting compensation amount corresponding to the cutting position. For example, when it moves to cutting position 1, it performs horizontal displacement according to the cutting compensation amount corresponding to cutting position 1; when it moves to cutting position 2, it performs horizontal displacement according to the cutting compensation amount corresponding to cutting position 2, and so on.

The value of N can be set according to actual production conditions, for example, the value of N can be 3-5.

As the production process continues, the hardware parameters of the multi-wire cutting device will continue to change. In order to ensure the timeliness and accuracy of the cutting compensation, the cutting compensation corresponding to each cutting position can be obtained once every preset cycle, for example, once every 24 hours.

Among them, the cutting position refers to the different positions of the attack workbench in the cutting direction. For example, the cutting path of the attack workbench in the cutting process can be divided into multiple cutting positions. As shown in Figure 3, the cutting path of the attack workbench can be about 300 mm. At each cutting position, the morphology of the silicon wafer obtained after cutting can be measured. Among them, Block1 represents the morphology curve of silicon wafer 1, Block2 represents the morphology curve of silicon wafer 2, and Block3 represents the morphology curve of silicon wafer 3. It can be seen that before the linear slide mechanism 02 is used for cutting compensation, the morphology change of the silicon wafer is large, which is not conducive to the quality of the silicon wafer.

In some embodiments, the cutting compensation amount at each cutting position is zero minus A, where A is the maximum value, minimum value or average value of multiple morphological changes of the multiple silicon wafers at the cutting position.

In a specific example, as shown in FIG4 , the average morphology variation curves of multiple silicon wafers are calculated, and the average morphology variation curve is subtracted from zero to obtain the cutting compensation curve, which indicates the cutting compensation corresponding to each cutting position. For example, at the cutting position of 50 mm (that is, after the attack workbench moves 50 mm in the cutting direction from the initial position, wherein the cutting line just touches the crystal rod when the attack workbench is at the initial position), the average morphology variation of multiple silicon wafers is 4 um, and the corresponding cutting compensation is -4 um; at the cutting position of 100 mm, the average morphology variation of multiple silicon wafers is 4 um, and the corresponding cutting compensation is -4 um.

When cutting, the movement control structure 06 controls the linear slide mechanism 02 to perform horizontal displacement according to the cutting compensation amount, which can improve the morphology of the silicon wafer. The improved silicon wafer morphology is shown in FIG5 . It can be seen that the morphology uniformity of the silicon wafer is improved, which can improve the quality of the cut silicon wafer.

In this embodiment, after cutting is completed, the morphology of the silicon wafer obtained after cutting can be measured to determine whether the morphology uniformity of the silicon wafer is improved. If it is not significantly improved, the morphology data of the silicon wafer can be fed back to the motion control structure 06, and the motion control structure 06 can readjust the cutting compensation amount.

The above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. If the present invention is modified or replaced by something equivalent without departing from the spirit and scope of the present invention, it should be included in the protection scope of the patent application of the present invention.

01: Attack workbench 02: Linear slide mechanism 03: Crystal rod fixing structure 04: Crystal rod 05: Cutting structure 06: Movement control structure 101-102: Steps

FIG1 is a schematic diagram of the structure of the multi-wire cutting device of the embodiment of the present invention; FIG2 is another schematic diagram of the structure of the multi-wire cutting device of the embodiment of the present invention; FIG3 is a schematic diagram of the silicon wafer morphology of the embodiment of the present invention; FIG4 is a schematic diagram of the compensation amount obtained in the embodiment of the present invention; FIG5 is a schematic diagram of the improvement of the silicon wafer morphology of the embodiment of the present invention; FIG6 is a schematic diagram of the process of the multi-wire cutting method of the embodiment of the present invention.

101-102: Steps

Claims (10)

A multi-wire cutting device includes: an attack workbench; a crystal rod fixing structure arranged on the attack workbench, the crystal rod fixing structure fixing the crystal rod to be cut; a cutting structure arranged above the attack workbench, including at least two wire rollers and a plurality of cutting wires wound around the at least two wire rollers; a linear slide mechanism located between the attack workbench and the crystal rod fixing structure, capable of horizontal displacement along the crystal rod axis, and after the linear slide mechanism moves, the horizontal position of the feed shaft of the attack workbench can be changed; a movement control structure, used to control the linear slide mechanism to perform horizontal displacement according to the cutting compensation amount. The multi-wire cutting device as described in claim 1, further comprising: a cutting compensation amount acquisition mechanism, used to cut N test crystal rods using the multi-wire cutting device with a fixed position of the linear slide mechanism to obtain multiple silicon wafers, where N is a positive integer; collect the morphological changes of the multiple silicon wafers at different cutting positions; and determine the cutting compensation amount of each cutting position according to the morphological change. A multi-wire cutting device as described in claim 2, wherein the cutting compensation amount at each cutting position is zero minus A, and A is the maximum value, minimum value or average value of multiple morphological changes of the multiple silicon wafers at the cutting position. A multi-wire cutting device as described in claim 2, wherein N is 3-5. A multi-wire cutting device as described in claim 2, wherein during the cutting process, the movement speed of the cutting wire is 500-1200 m/min. A multi-wire cutting device as described in claim 2, wherein the cutting structure includes two sets of wire rollers spaced apart by a first preset distance along a first direction and arranged side by side, each set of wire rollers includes two wire rollers spaced apart by a preset distance in a second direction, the first direction is a direction perpendicular to the extension direction of the plurality of cutting wires, and the second direction is a direction perpendicular to the first direction. The multi-wire cutting device as described in claim 6 also includes a cooling structure for cooling the cutting wires, the cooling structure including nozzles arranged on opposite sides of the crystal rod fixing structure along the second direction, and the nozzles are connected to the cooling medium storage part through a pipeline. A multi-wire cutting method is applied to a multi-wire cutting device as described in any one of claims 1 to 7, the method comprising: when the attack worktable moves, the movement control structure controls the linear slide mechanism to perform horizontal displacement along the axial direction of the crystal rod according to the cutting compensation amount, thereby changing the horizontal position of the feed axis of the attack worktable. The multi-wire cutting method as described in claim 8 further includes the step of obtaining a cutting compensation amount, and obtaining the cutting compensation amount includes: using the multi-wire cutting device with a fixed position of the linear slide mechanism to cut N test crystal rods to obtain multiple silicon wafers, where N is a positive integer; collecting the morphological changes of the multiple silicon wafers at different cutting positions; and determining the cutting compensation amount of each cutting position according to the morphological change amount. The multi-wire cutting method as described in claim 9, wherein the cutting compensation amount at each cutting position is zero minus A, and A is the maximum value, minimum value or average value of the multiple morphological changes of the multiple silicon wafers at the cutting position.