TW202021701A - Device for slicing ingot - Google Patents

Abstract

The present application provides a device for slicing a silicon ingot comprising a power source; an electrolytic cell for storing an electrolyte; an anode comprising an ingot supporting device and an ingot, wherein the ingot supporting device electrically connects to the power source and the ingot respectively; a cathode located in the electrolytic cell and electrically connecting to the power source, wherein the cathode comprises at least one wire electrode, and the direction of the length of the wire electrode crosses with the axis of the ingot but the wire electrode is contactless with the ingot, and the silicon ingot is sliced through the relative motion of the wire electrode and the ingot while the power source is turned on between the anode and the cathode. The cathode further comprises a wire electrode supporting device for controlling the movement of the wire electrode along with the direction of the length of the wire electrode. By applying the device for slicing the ingot of the present application, the hydrogen gas produced from the wire electrode of the cathode can be timely removed.

Description

Crystal rod slicing device

The present invention relates to the field of semiconductor manufacturing, in particular to an ingot slicing device.

At present, the cutting of ingots is dominated by mechanical wire cutting in which steel wires drive slurry. The principle is to use a high-speed steel wire to drive the cutting blade material attached to the steel wire to rub the silicon rod to achieve the cutting effect. Since steel wire is used in the wire cutting process, it is easy to introduce contaminants such as copper (Cu) and iron (Fe). At the same time, the wire cutting method is used to cut the ingot, which cannot avoid cutting loss.

An improved method for cutting ingots is to electrochemically cut the ingots by electrolysis. By arranging the crystal rod and the linear electrode on the anode and the cathode of the electrolysis device containing the electrolyte, when a DC power supply is applied between the cathode and the anode, the linear electrode and the crystal rod correspond to the linear electrode Part of the electrochemical reaction occurs, causing the crystal rod to be cut. In this process, the electrochemical reaction of hydrogen evolution occurs on the cathode set as the wire electrode, but the hydrogen gas that is precipitated is often adsorbed on the wire electrode, which causes the surface reaction activity of the wire electrode to decrease, and the electrochemical reaction of the subsequent crystal bar cutting The efficiency drops or even cannot be carried out, which affects the efficiency and quality of ingot cutting.

Therefore, it is necessary to propose a new crystal rod slicing device to solve the problems in the prior art.

A series of simplified concepts are introduced in the content of the invention, which will be explained in further detail in the detailed implementation section. The inventive content part of the present invention does not mean an attempt to limit the key features and necessary technical features of the claimed technical solution, nor does it mean an attempt to determine the protection scope of the claimed technical solution.

The present invention provides a crystal rod slicing device, which includes: power supply; Electrolysis cell, used to store electrolyte; An anode, the anode includes a crystal rod support device and a crystal rod, and the crystal rod support device is electrically connected to the power supply and the crystal rod respectively; The cathode is accommodated in the electrolytic cell and is electrically connected to the power source. The cathode includes at least one linear electrode. The longitudinal direction of the linear electrode is intersected with the axial direction of the crystal rod, and the The linear electrode is not in contact with the crystal rod, and the crystal rod is sliced by the relative movement between the linear electrode and the crystal rod when the power supply is connected between the anode and the cathode; Wherein, the cathode further includes a linear electrode supporting device that controls the linear electrode to move along the length direction of the linear electrode.

Exemplarily, the linear electrode supporting device also controls the linear electrode to move along the axial direction of the crystal rod and/or the radial direction of the crystal rod.

Exemplarily, the linear electrode supporting device includes at least two guide rollers, and the rotation of the guide roller drives the linear electrode to move along the length direction of the linear electrode.

Exemplarily, a wire groove is provided on the guide roller, and the distance between adjacent wire grooves is set to the thickness of a wafer formed by slicing the crystal rod.

Exemplarily, the distance between adjacent wire grooves ranges from 100 μm to 1500 μm.

Exemplarily, the material of the guide roller includes graphite, carbon-coated metal material and conductive ceramic.

Exemplarily, it also includes a pH control device for controlling the pH value in the electrolytic cell.

Exemplarily, it further includes a temperature control device to control the temperature of the cathode, the anode and the electrolyte.

Exemplarily, it also includes a hydrogen collecting device for collecting hydrogen generated by the electrochemical reaction on the cathode.

Exemplarily, an electrolyte circulation system is also included to circulate and replenish the electrolyte in the electrolytic cell.

According to the ingot slicing device of the present invention, a linear electrode supporting device capable of supporting the linear electrode to move along its length is provided on the cathode, so that during the electrochemical cutting of the ingot on the wafer, the linear electrode on the cathode The hydrogen precipitated on the surface is removed in time to avoid the adsorption of hydrogen on the linear electrode to affect the efficiency of the cathode electrochemical reaction, and to ensure the efficiency and quality of the ingot cutting.

In the following description, a lot of specific details are given to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features known in the art are not described.

In order to thoroughly understand the present invention, a detailed description will be provided in the following description to illustrate the ingot slicing device of the present invention. Obviously, the implementation of the present invention is not limited to the specific details familiar to those skilled in the semiconductor field. The preferred embodiments of the present invention are described in detail as follows. However, in addition to these detailed descriptions, the present invention may also have other embodiments.

It should be noted that the terms used here are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprising" and/or "including" are used in this specification, they indicate the presence of the features, wholes, steps, operations, elements, and/or elements, but do not exclude the presence or One or more other features, wholes, steps, operations, elements, elements, and/or combinations thereof are added.

Now, exemplary embodiments according to the present invention will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many different forms, and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the concept of these exemplary embodiments to those of ordinary skill in the art. In the drawings, the thicknesses of layers and regions are exaggerated for clarity, and the same reference numerals are used to denote the same elements, and thus their descriptions will be omitted.

In order to solve the technical problems in the prior art, the present invention provides an ingot slicing device, which includes: power supply; Electrolysis cell, used to store electrolyte; An anode, the anode includes a crystal rod support device and a crystal rod, and the crystal rod support device is electrically connected to the power supply and the crystal rod respectively; The cathode is accommodated in the electrolytic cell and is electrically connected to the power source. The cathode includes at least one linear electrode. The longitudinal direction of the linear electrode is intersected with the axial direction of the crystal rod, and the The linear electrode is not in contact with the crystal rod, and the crystal rod is sliced by the relative movement between the linear electrode and the crystal rod when the power supply is connected between the anode and the cathode; Wherein, the cathode further includes a linear electrode supporting device that controls the linear electrode to move along the length direction of the linear electrode.

Hereinafter, the ingot slicing device proposed by the present invention will be exemplarily described with reference to Figs. 1, 2 and 3A and 3B. Fig. 1 is a schematic structural diagram of an ingot slicing device according to an embodiment of the present invention; Fig. 2 3A and 3B are schematic diagrams of the cross-sectional structure of the ingot support device in FIG. 1 taken along the AA direction and the BB direction respectively.

First, referring to FIG. 1, the ingot slicing device according to an embodiment of the present invention includes a power source 100, an electrolytic cell 200, and an anode and a cathode connected to the anode and the cathode of the power source 100, respectively.

The power supply 100 may be any device that can provide DC voltage or current, such as an AC power supply and an AC-to-DC device that cooperate to provide DC voltage or current, DC power, etc., which are not limited herein.

The electrolytic cell 200 includes an electrolyte 201, which is used to react with the silicon crystal rod under the action of a DC power supply.

The anode includes an ingot 300 and an ingot support device 301 for supporting the ingot 300, wherein the ingot support device 301 is electrically connected to the power supply 100 and the ingot 300, respectively.

The cathode is contained in the electrolytic cell 200 and includes at least one linear electrode 400. The length direction of the linear electrode 400 is arranged to cross the axial direction of the ingot 300, and the linear electrode 400 and the ingot 300 are not in contact with each other.

Exemplarily, the material of the linear electrode 400 may be any non-metal conductive material. Specifically, the material of the linear electrode 400 may be carbon fiber, carbon-coated metal wire, or the like. Exemplarily, the diameter of the linear electrode ranges from 50-150 μm.

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Exemplarily, the electrolyte 201 includes a solution containing hydrofluoric acid. The length direction of the linear electrode 400 is intersected with the axial direction of the ingot 300, and the linear electrode 400 is not in contact with the ingot 300. When the power supply 100 applies a voltage or current between the cathode and the anode, the linear electrode 400 and An electrochemical reaction occurs in the part of the crystal rod 300 that is disposed opposite to the linear electrode 400. Among them, the crystal rod located on the anode undergoes the following electrochemical reactions:

The following electrochemical reactions occur on the cathode wire electrode:

In an embodiment according to the present invention, a solution containing hydrofluoric acid and acetic acid is used as the electrolyte, wherein the volume fraction of hydrofluoric acid is in the range of 1%-10%, and the volume fraction of acetic acid is in the range of 0. -30%.

Exemplarily, the angle range between the length direction of the crystal rod 300 and the length direction of the linear electrode 400 is 89.5°-90.5°. Under this angle range, the axial direction of the ingot 300 is perpendicular to the extending direction of the linear electrode 400, so that the slicing is carried out along the radial direction of the ingot 300, and the cut wafer meets the requirements for wafers in the semiconductor manufacturing method. .

Referring to FIG. 2, there is shown a schematic front view of the wafer support device in FIG. 1 supporting the wafer relative to the linear electrode. The linear electrode 400 is contained in the electrolyte 201 of the electrolytic cell 200, and the linear electrode 400 is opposed to the wafer The axial direction of 300 is vertically arranged, and the linear electrode 400 is not in contact with the crystal rod 300. In the above configuration of the power supply, electrolytic cell, cathode and anode, the ingot 300 is located between the ingot support device 301 and the linear electrode 400 of the cathode, which is achieved by the relative movement between the linear electrode 400 and the ingot 300 A slice of the ingot 300. The electrochemical method is used for cutting. Compared with the mechanical cutting method using the cutting wire, the cut loss during the cutting of the ingot is effectively reduced. At the same time, the electrochemical method of cutting the ingot to achieve non-contact cutting is effectively avoided. Mechanical damage, wafer warpage, and contamination from contact cutting. At the same time, the use of electrochemically cut wafers does not require further processing such as chemical etching, which greatly simplifies the processing flow of the cut wafers.

Exemplarily, as shown in FIG. 1, the cathode further includes a linear electrode supporting device 401 that controls the linear electrode 400 to move along its length direction. In the above electrochemical reaction, hydrogen (H ₂ ) is precipitated on the cathode, and hydrogen is often adsorbed on the linear electrode 400, so that the surface reaction activity of the linear electrode 400 is reduced, which affects the subsequent electrochemical reaction efficiency, and then affects the ingot slicing rate And slice quality. For this reason, the linear electrode support device 401 is used to support the linear electrode 400 to move in the longitudinal direction, so that the H ₂ adsorbed on the surface of the linear electrode 400 is removed with the movement of the linear electrode, and the linear electrode 400 is not The part that has adsorbed H ₂ moves to the bottom of the crystal rod for further electrochemical cutting, which effectively solves the influence of H ₂ adsorbed on the surface of the linear electrode on electrochemical cutting.

Exemplarily, the linear electrode supporting device includes at least two guide rollers. As shown in FIG. 1, the linear electrode supporting device 401 is configured as two guide rollers. Through the rotation of the guide rollers, the guide rollers drive the linear electrode 400 to move in the length direction. The linear electrode support device 401 is set as a guide roller on the one hand to support the linear electrode 400, so that the linear electrode 400 is in a tensioned state, and on the other hand, the linear electrode 400 is driven along the length direction by the rotation of the guide roller. When the linear electrode moves through the guide roller under this configuration, the H ₂ adsorbed on the linear electrode is completely desorbed by contact with the guide roller, so that the H ₂ desorption efficiency is high.

Referring to FIG. 3, there is shown a schematic front view of the ingot support device supporting wafer in FIG. 2 relative to the linear electrode and the linear electrode supporting device. The linear electrode 400 is contained in the electrolyte 201 of the electrolytic cell 200, The extending direction of the linear electrode 400 is perpendicular to the axial direction of the crystal rod 300, and the linear electrode 400 does not contact the crystal rod 300. The linear electrode support device 401 configured as a guide roller rotates along the direction indicated by the arrow CC, and drives the linear electrode 400 to move along its length extension direction, thereby desorbing the H ₂ adsorbed on the surface during the electrochemical reaction. Exemplarily, the material of the guide roller includes graphite, carbon-coated metal material and conductive ceramic. In this embodiment, the material of the guide roller is graphite. Exemplarily, the linear speed at which the guide roller drives the linear electrode to rotate is 0-10 millimeters per second (mm/s).

It should be understood that the setting of the linear electrode support device as a guide roller in this embodiment is only exemplary, and any linear electrode support device that can move the linear electrode in the length direction is applicable to the present invention. At the same time, it needs to be understood that setting the linear electrode as two guide rollers in the drawings of this embodiment is not intended to limit it. Those skilled in the art will set the linear electrode as two, three or more guide rollers to make the linear electrode The present invention can be realized by moving the shaped electrode along the length direction.

Exemplarily, the linear electrode supporting device also controls the linear electrode to move along the axial direction of the crystal rod and/or the radial direction of the crystal rod. The wire electrode support device 401 supports the wire electrode 400 to move along the axis of the crystal rod 300. When there are fewer linear electrodes, it cannot pass between the crystal rod 300 and the wire electrode 400. One-time cutting is to cut the ingot 300 to the required thickness. By moving the linear electrode 400 along the axial direction of the ingot 300, the ingot 300 is cut multiple times, and finally the ingot 300 is cut. Into the required thickness of the wafer.

When the linear electrode support device 401 supports the linear electrode 400 to move along the radial direction of the crystal rod 300, the relative movement between the linear electrode 400 and the crystal rod 300 can be realized. In this process, the linear electrode 400 and the crystal rod 300 can be moved together. The rod 300 never touches. It should be understood that the use of the linear electrode support device to support the linear electrode to move along the axis of the crystal rod to realize the relative movement between the linear electrode support device and the crystal rod in this embodiment is merely exemplary. Those skilled in the art It should be understood that the present invention can be realized by controlling the movement of the crystal rod along its radial direction or simultaneously controlling the movement of the linear electrode and the crystal rod along the radial direction of the crystal rod to realize the relative movement between the linear electrode and the crystal rod.

When the wire electrode supporting device is provided as a guide roller, a wire groove is provided on the guide roller to fix the position of the wire electrode. Exemplarily, the distance between the linear electrodes is set by setting the distance of the wire groove on the guide roller. Exemplarily, the distance between adjacent wire grooves ranges from 100 micrometers (µm) to 1500 µm. In the existing semiconductor manufacturing technology, the thickness of the wafer is often set to 100µm -1500µm, and the distance between the wire grooves is set to 100µm -1500µm, so that the distance between adjacent linear electrodes is 100µm -1500µm. The wire electrode cuts the ingot to form a cut wafer.

Exemplarily, the anode further includes a crystal rod supporting device. As shown in FIG. 1, an ingot support device 301 is provided on the anode to support the ingot 300 and is connected to the positive pole of the power supply, and the ingot support 301 is electrically connected to the ingot 300.

Illustratively, refer to FIGS. 3A and 3B, which show schematic cross-sectional structure diagrams of the crystal rod supporting device in FIG. 1 along the A-A direction and the B-B direction. The ingot support device 301 is used to support the ingot 300 and includes a first part 3011 and a second part 3012. The first part 3011 is electrically connected to the power source 100, and the second part 3012 is in contact with the ingot 300. Among them, the first part 3011 is arranged in a strip shape, and the second part 3012 is arranged in a comb tooth structure. Further, as shown in FIG. 1, the second part 3012 configured as a comb tooth structure includes a convex part 30121 configured as a comb tooth and a concave part 30122 located between the comb teeth. The linear electrode 400 is arranged corresponding to the concave portion 30122 of the comb-tooth structure. During the electrolysis reaction, the portion on the crystal rod 300 corresponding to the concave portion 30122 forms the anode in the electrolytic reaction corresponding to the linear electrode 400 on the cathode, and the concave portion 30122 corresponds to The part of the crystal rod 300 is consumed by the electrochemical reaction, while the part of the crystal rod 300 corresponding to the convex portion 30121 does not participate in the reaction and remains, and finally forms the effect of cutting the crystal rod along the concave portion on the comb tooth structure. Exemplarily, referring to FIG. 3A, the width D of the convex portion 30121 of the comb-tooth structure on the second portion 3012 is set to the thickness of the wafer formed by slicing the crystal rod. Exemplarily, the thickness of the silicon wafer ranges from 100 μm to 1500 μm, and the width of the convex portion on the comb tooth structure ranges from 100 μm to 1500 μm. In one example, the thickness of the silicon wafer is 750 µm, and the width of the convex portion of the comb tooth structure is 750 µm. Exemplarily, the size range of the concave portion is 80-200 μm.

Exemplarily, the material of the crystal rod supporting device 301 may be any non-metallic conductive material. Specifically, the crystal rod supporting device 301 can be set to graphite. Carbon coated metal materials or conductive ceramics, etc.

Further, illustratively, the ingot supporting device 301 and the ingot 300 are connected by conductive glue, so as to realize the electrical connection between the ingot supporting device 301 and the ingot 300.

According to an embodiment of the present invention, the crystal rod slicing device further includes a pH control device for controlling the pH in the electrolytic cell. Exemplarily, the electrolyte is configured to include a mixture of hydrofluoric acid and acetic acid. Among them, acetic acid is used as a buffering agent to adjust the pH value of the entire electrolyte on the one hand, and increase the conductivity of the electrolyte on the other hand. Exemplarily, the pH control device includes a pH detector and an acetic acid supply device.

According to an embodiment of the present invention, the crystal rod slicing device further includes a temperature control device for controlling the temperature of the cathode, the anode, and the electrolyte. Exemplarily, the temperature control device includes a thermometer and a water cooling device. Exemplarily, the temperature control device controls the temperature of the cathode, the anode and the electrolyte to be between 22°C and 24°C.

According to an embodiment of the present invention, the crystal rod slicing device further includes a hydrogen collecting device for collecting hydrogen generated by the electrochemical reaction on the cathode. In order to avoid the danger caused by the hydrogen produced by the cathode, the entire ingot slicing device is set up as a closed system, and at the same time, the gas in the closed system is collected by a pump, etc., to collect the hydrogen.

According to an embodiment of the present invention, the crystal rod slicing device further includes an electrolyte circulation system for replenishing the electrolyte in the electrolytic cell. Exemplarily, the electrolyte circulation system includes an acid-resistant pump and a screening program. The electrolyte is drawn out through the acid-resistant pump. The screening program filters out metals and particles, and then loops the filtered electrolyte into the electrolytic cell to effectively improve The use efficiency of the electrolyte is improved, and the production cost is reduced.

In summary, according to the ingot slicing device of the present invention, a linear electrode support device capable of supporting the linear electrode to move along its length is provided on the cathode, so that during the electrochemical cutting of the ingot on the wafer, The hydrogen precipitated on the linear electrode of the cathode is removed in time to prevent it from being adsorbed on the linear electrode to affect the efficiency of the cathode electrochemical reaction, ensuring the efficiency and quality of the ingot cutting.

The present invention has been described by the above-mentioned embodiments, but it should be understood that the above-mentioned embodiments are only for the purpose of illustration and description, and are not intended to limit the present invention to the scope of the described embodiments. In addition, those skilled in the art can understand that the present invention is not limited to the above-mentioned embodiments, and more variations and modifications can be made according to the teachings of the present invention, and these variations and modifications fall under the protection of the present invention. Within the range. The protection scope of the present invention is defined by the appended claims and their equivalent scope.

100: Power 200: electrolytic cell 201: Electrolyte 300: crystal rod 301: Crystal rod support device 3011: Part One 3012: Part Two 30121: convex 30122: recess 400: wire electrode 401: Wire electrode support device D: width

Fig. 1 is a schematic structural diagram of an ingot slicing device according to an embodiment of the present invention.

FIG. 2 is a front view of the wafer support device in FIG. 1, which is a front view of the supporting wafer relative to the linear electrode.

3A and 3B are schematic diagrams of the cross-sectional structure of the crystal rod supporting device in FIG. 1, taken along the A-A direction and the B-B direction, respectively.

100: Power

200: electrolytic cell

201: Electrolyte

300: crystal rod

301: Crystal rod support device

400: wire electrode

401: Wire electrode support device

Claims (10)

A crystal rod slicing device includes: power supply; Electrolysis cell, used to store electrolyte; An anode, the anode includes a crystal rod support device and a crystal rod, and the crystal rod support device is electrically connected to the power supply and the crystal rod respectively; The cathode is accommodated in the electrolytic cell and is electrically connected to the power source. The cathode includes at least one linear electrode. The longitudinal direction of the linear electrode is intersected with the axial direction of the crystal rod, and the The wire electrode is not in contact with the crystal rod, and when the power supply is connected between the anode and the cathode, the crystal rod is sliced by the relative movement between the wire electrode and the crystal rod; wherein, The cathode further includes a wire electrode supporting device that controls the movement of the wire electrode along the length direction of the wire electrode. The crystal rod slicing device according to the first item of the scope of patent application, wherein the linear electrode supporting device also controls the linear electrode to move along the axial direction of the crystal rod and/or the radial direction of the crystal rod. The ingot slicing device according to the first patent application, wherein the linear electrode supporting device includes at least two guide rollers, and the rotation of the guide roller drives the linear electrode to move along the length direction of the linear electrode . For example, the ingot slicing device of the third item in the scope of patent application, wherein a wire groove is provided on the guide roller, and the distance between adjacent wire grooves is set to the thickness of the wafer formed by slicing the ingot. For example, the ingot slicing device of item 4 of the scope of patent application, wherein the distance between adjacent wire grooves ranges from 100 µm to 1500 µm. Such as the ingot slicing device of the third item of the scope of patent application, wherein the material of the guide roller includes graphite, carbon-coated metal material and conductive ceramic. For example, the crystal rod slicing device of the first item in the scope of the patent application also includes a pH control device for controlling the pH value in the electrolytic cell. The ingot slicing device as in the first item of the scope of the patent application further includes a temperature control device for controlling the temperature of the cathode, the anode and the electrolyte. For example, the ingot slicing device of the first item of the scope of the patent application further includes a hydrogen collecting device for collecting the hydrogen generated by the electrochemical reaction on the cathode. For example, the crystal rod slicing device of the first item in the scope of the patent application also includes an electrolyte circulation system to circulate and replenish the electrolyte in the electrolytic cell.

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