JP2008243850A - Workpiece processing method, wiring forming method, and semiconductor substrate manufacturing method - Google Patents

Abstract

The present invention provides a processing method of a workpiece that can be easily processed into a desired shape without causing mechanical damage and thermal damage.
A sample 1 made of at least one material selected from the group consisting of silicon, silicon carbide, and a semiconductor containing a group III to V element is used as a workpiece, and the sample 1 is made of hydrogen fluoride or fluoride. It is immersed in a treatment liquid 8 made of an aqueous solution containing ions, and in this treatment liquid 8, the layer made of a catalyst in the oxidation reaction of the material is brought into contact with at least the wire 2 provided on the surface, and the wire 2 is made into an anode As a result of causing an electrochemical reaction at the contact portion with the sample 1, the contact portion with the wire 2 in the sample 1 is oxidized and dissolved in the treatment liquid 8. By moving the wire 2 by gravity, the sample 1 is cut or a cut is formed in the sample 1.
[Selection] Figure 2

Description

  The present invention relates to a workpiece processing method for processing a workpiece using an oxidation reaction of the workpiece, a wiring formation method using the processing method, and a semiconductor substrate manufacturing method.

  Conventionally, a mechanical processing method or a processing method using a laser is generally used as a processing method of a workpiece according to an industrial article.

  For example, as a semiconductor cutting process such as silicon, when cutting a wafer from a silicon ingot, or when a wafer having an integrated circuit formed on the surface is divided into individual chips (dicing blade) (dicing blade) ) And a method of mechanically scraping the surface of a semiconductor such as silicon is known (see, for example, Patent Document 1).

  As the dicing blade, a fine diamond abrasive grain electrodeposited with nickel or the like is used. In addition, when individual chips are divided from a wafer having an integrated circuit formed on the surface, a dicing blade using an extremely thin blade having a thickness of about 10 μm to 30 μm is used.

  Further, when a wafer is cut out from a silicon ingot, a wire saw is used (for example, see Patent Document 2). Cutting with a wire saw is performed by pressing a silicon ingot against a high-strength steel wire running at a high speed while supplying a slurry-like abrasive liquid containing loose abrasive grains in wrapping oil. This is done by cutting the ingot into silicon wafers by grinding action. According to this method, a plurality of wires can be pressed against the ingot at the same time, and many wafers can be cut out at a time. In addition, as a wire saw used in this case, a wire diameter of 120 μm or more is used.

On the other hand, in a processing method using a laser, a part of light energy absorbed by a workpiece such as silicon is converted into thermal energy by irradiating a portion to be cut with a high-power laser, and thereby processing the workpiece. Processing by melting, decomposition, and scattering of objects is performed (for example, see Patent Document 3).
Japanese Patent Laying-Open No. 2005-129741 (Publication date: May 19, 2005) JP 2006-224266 A (publication date: August 31, 2006) JP 2005-297039 A (publication date: October 27, 2005) Japanese Patent Laying-Open No. 2005-183505 (Publication date: July 7, 2005) International Publication No. 2003/105209 Pamphlet (International Publication Date: December 18, 2003) International Publication No. 02/23607 Pamphlet (International Publication Date: March 21, 2002) US Pat. No. 6,762,134 (Registration date: July 13, 2004) JP 2005-142457 A (Publication date: June 2, 2005) JP 2006-114632 A (publication date: April 27, 2005) Kazuya Tsujino, 1 other, "Boring Deep Cylindrical Nanoholes in Silicon Using Silver Nanoparticles as a Catalyst", ADVANCED MATERIALS 2005, 17, No. 8, April 18, p1045-1047 Kazuya Tsujino, 1 other, "Helical Nanoholes Bored in Silicon by Wet Chemical Etching Using Platinum Nanoparticles as Catalyst", Electrochemical and Solid-State Letters, 8, (12), C193-195, (2005) K. Tsujino, 2 others, “Texturization of multicrystalline silicon wafers for solar cells by chemical treatment using metallic catalyst”, Solar Energy Materials & Solar Cells, 90, (2006), p100-110 X. Li, 1 other, “Metal-assisted chemical etching in HF / H2O2 produced porous silicon”, APPLIED PHYSICS LETTERS, Vol.77, No.16, October 16, 2000, p.2572-2574 Kuiqing Peng, 5 others, “Uniform, Axial-Orientation Alignment of One-Dimensional Single-Crystal Silicon Nanostructure Arrays”, Angewandte Chemie Int. Ed., 2005, 44, p2737-2742 K. Tsujino, 1 other, “Formation of a low reflective surface on crystalline silicon solar cells by chemical treatment using Ag electrodes as the catalyst”, Solar Energy Materials & Solar Cells, 90, (2006), p1527-1532 TLRittenhouse, 2 others, “Structural and spectroscopic characterization of porous silicon carbide formed by Pt-assisted electroless chemical etching”, Solid State Communications 126, (2003), p245-250 HIDEYUKI HARA, 7 others, "Novel Abrasive-Free Planarization of 4 H-Sic (0001) Using Catalyst", Journal of ELECTRONIC MATERIALS, Vol.35, No.8, 2006, L11-L14

  However, as shown in Patent Documents 1 and 2, in a physical processing method using a dicing blade or a wire saw, minute cracks or chipping occurs around the scraped part, excessive stress is generated, A workpiece such as a wafer may be damaged.

  In addition, as shown in Patent Document 3, in the case of laser processing, although mechanical damage does not occur, there is a problem that damage is caused by heat around the laser irradiation site. Such damage often adversely affects the performance of semiconductor devices formed on silicon. For this reason, it is desired to develop a method for processing a workpiece without mechanically or thermally damaging the workpiece.

  In addition, as described above, as a method of processing a workpiece on an industrial article without causing mechanical or thermal damage resulting from the processing, a method of drilling the workpiece using a chemical reaction, particularly an oxidation reaction In recent years, however, several proposals have been proposed including proposals by the present inventors.

  As such a chemical processing method, metal particles or a discontinuous metal thin film is attached to the surface of a silicon substrate or the like as a catalyst, and the silicon substrate or the like to which the metal particles are attached is bonded to an oxidizing agent and hydrofluoric acid. (For example, see Patent Documents 4 to 7 and Non-Patent Documents 1 to 5), a semiconductor crystal substrate such as a silicon substrate, or the like. A metal having a catalytic function of a reduction reaction with respect to an oxidizing agent is deposited or baked on the surface of the substrate after baking to form a metal thin film (electrode), and this semiconductor crystal substrate is immersed in an aqueous solution containing the oxidizing agent. Thus, there is a method of forming a porous layer around the metal thin film (see, for example, Patent Document 8 and Non-Patent Documents 6 and 7).

  However, none of the conventional methods using these chemical reactions cause mechanical or thermal damage to the workpiece, but it is not easy to control, and local processing or a desired part can be formed in a desired shape. It is unsuitable for processing.

  The above conventional methods are all intended for perforation, but as shown in Patent Documents 4 to 7 and Non-Patent Documents 1 to 5, catalyst particles are attached to a workpiece such as a silicon substrate and left as it is. Then, holes grow in a direction along a specific crystal orientation of the workpiece or in a direction perpendicular to the substrate surface, but the movement of the catalyst particles inside the workpiece such as a silicon substrate cannot be controlled. It is not easy to control the drilling direction. Further, Patent Document 8 and Non-Patent Documents 6 and 7 make the periphery of the metal layer evenly polymorphic, and it is impossible to locally process only a desired position.

  Furthermore, all of the above conventional methods are intended for drilling and not for cutting.

  The present invention has been made in view of the above-described conventional problems, and the object thereof is to provide a workpiece that can be easily processed into a desired shape without causing mechanical damage and thermal damage. It is to provide a processing method. A further object of the present invention is to provide a wiring forming method using the above-described workpiece processing method and a semiconductor substrate manufacturing method.

  In order to solve the above-described problems, a processing method for a workpiece according to the present invention includes a processing tool having at least a surface made of a conductive material on a surface of the workpiece, between the workpiece and the processing tool. Supplying a treatment liquid containing a solvent inert to the material constituting the workpiece and a reactive substance that reacts with the oxide of the material constituting the workpiece and dissolves the oxide in the solvent. And contacting the workpiece with the workpiece using the workpiece as an anode to oxidize the contact portion of the workpiece with the workpiece to the aqueous solution. The workpiece is processed by moving the contact portion between the workpiece and the processing tool by moving the workpiece or the processing tool along with the melting of the workpiece. It is said.

  More specifically, in order to solve the above-described problem, a processing method for a workpiece according to the present invention includes a processing tool having at least a surface made of a conductive material on the surface of the workpiece. A solvent inert to the material constituting the workpiece, and a reactive substance that reacts with the oxide of the material constituting the workpiece and dissolves the oxide in the solvent, between the processing tool and the workpiece The contact portion of the workpiece with the processing tool is caused to contact with the processing tool while supplying the processing liquid, and an electrochemical reaction is caused at the contact portion with the workpiece using the processing tool as an anode. The workpiece is oxidized and dissolved in the aqueous solution, and the workpiece or the processing tool is moved along with the dissolution of the workpiece to move the contact portion between the workpiece and the processing tool, thereby moving the workpiece. It is characterized by processing.

  In particular, a method for processing a workpiece according to the present invention includes a workpiece made of at least one material selected from the group consisting of silicon, silicon carbide, and a semiconductor containing a group III-V element. The workpiece is immersed in an aqueous solution containing hydrogen fluoride or fluoride ions, and in the aqueous solution, at least the surface is made of a conductive material and is brought into contact with a processing tool formed separately from the workpiece. And, by causing an electrochemical reaction at the contact portion with the workpiece using the processing tool as an anode, the contact portion with the processing tool in the workpiece is oxidized and dissolved in the aqueous solution, The workpiece is processed by moving the contact portion between the workpiece and the processing tool by moving the workpiece or the processing tool along with the melting of the workpiece.

  In the present invention, the conductive material is preferably a material having a catalytic action in an oxidation reaction of a material constituting the workpiece. For example, the conductive material is preferably at least one metal selected from the group consisting of platinum, gold, iridium, and alloys thereof.

  Moreover, it is preferable that the said processing tool is formed in wire shape, blade shape, or needle shape.

  As described above, the present invention is a method of processing the workpiece by a chemical reaction using a catalyst, specifically, an oxidative dissolution reaction of the workpiece. Further, according to each of the above methods, the workpiece is locally and selectively dissolved (etched) in the contact portion with the processing tool and in the vicinity thereof, and the processing tool or the workpiece is removed. By moving, the contact portion between the workpiece and the processing tool can be moved in a desired direction, and the progress of processing (the degree of processing) can be easily grasped. Therefore, processing control is easy.

  Therefore, according to each of the above methods, there is an effect that the workpiece can be easily processed into a desired shape without causing mechanical damage and thermal damage.

  In addition, each of the above methods does not cause crystal defects due to damage at the time of processing, is advantageous from the viewpoint of post-processing steps and device characteristics, and does not require a mechanical polishing cutting step. It is easy to manufacture a thin wafer. Furthermore, basically, it is sufficient to simply immerse the workpiece in a treatment liquid such as the aqueous solution, and scale-up is easy.

  In addition, the conventional processing method using a wire saw or a laser is high in cost, and for example, when a semiconductor wafer is manufactured using these conventional methods, the whitening becomes large. It is wasteful in terms of resources.

  On the other hand, according to the present invention, there is no need for mechanical polishing cutting, and in addition to the overwhelmingly low equipment cost, for example, as the processing tool, an ultrafine wire can be used. The workpiece can be cut or formed with the line width. Therefore, according to each of the above methods, cutting can be performed at low cost and with little waste of energy and resources.

  Therefore, in each of the above methods, it is preferable that the processing tool has a linear processing surface, and the processing is formation of a cut in the workpiece or cutting of the workpiece.

  In addition, in order to solve the above-described problem, the wiring forming method according to the present invention provides a workpiece made of at least one material selected from the group consisting of silicon, silicon carbide, and a semiconductor containing a group III-V element. Immersing in an aqueous solution containing hydrogen fluoride or fluoride ions, and in the aqueous solution, at least the surface is made of a conductive material, and is brought into contact with a processing tool formed separately from the workpiece; and By causing an electrochemical reaction at the contact portion with the workpiece using the processing tool as an anode, the contact portion with the processing tool in the workpiece is oxidized and dissolved in the aqueous solution. A hole or groove is formed in the workpiece by moving the contact portion between the workpiece and the processing tool by moving the workpiece or the processing tool as the product is melted, and then forming the hole or groove in the workpiece. To, is characterized in that to leave at least part of the processing tool used to form the pores or grooves.

  In order to solve the above problems, a method for producing a semiconductor substrate according to the present invention includes a semiconductor wafer made of at least one material selected from the group consisting of silicon, silicon carbide, and a semiconductor containing a group III-V element. Is immersed in an aqueous solution containing hydrogen fluoride or fluoride ions, and in the aqueous solution, at least the surface is made of a conductive material and is contacted with a processing tool formed separately from the semiconductor wafer, and By causing an electrochemical reaction at the contact portion with the semiconductor wafer using the processing tool as an anode, the contact portion with the processing tool in the semiconductor wafer is oxidized and dissolved in the aqueous solution, and the semiconductor wafer is dissolved. Accordingly, by moving the semiconductor wafer or the processing tool, the contact portion between the semiconductor wafer and the processing tool is moved to move the semiconductor wafer. After forming the holes or grooves in, the pores or the groove, it is characterized by forming a machining tool wiring be left at least a portion of which was used in the formation of the hole or groove.

  The processing tool left in the hole or groove may be used as a wiring as it is, or the conductive material on the surface of the processing tool left in the hole or groove is used as a catalyst for wiring formation by film growth. The wiring may be formed by using it.

  When a hole is formed in a workpiece by a drilling technique using metal particles, and wiring is formed by depositing wiring material inside the hole by a method such as plating or vapor deposition, the obtained wiring has fine particles. The structure is like a collection, and there are many defects.

  In addition, when a wiring material is arranged in a hole after drilling a workpiece using metal particles, in order to obtain a wiring penetrating the substrate, the drilling is stopped before the metal particles penetrate the substrate. A process of depositing the wiring material therein and polishing and removing the substrate material from the back surface of the substrate to the bottom of the hole is required.

  On the other hand, according to the present invention, the processing tool can be used as a wiring as it is, or a wiring is formed by film growth using a catalyst on the surface of the processing tool. There is also an effect that it is possible to form a wiring that is free of defects or has fewer defects than the conventional method.

  In addition, as described above, after forming holes or grooves in a workpiece such as a semiconductor wafer, at least a part of the processing tool is left as a wiring in a processing portion such as a hole or groove, thereby forming holes or grooves. The formation of the groove and the formation of the wiring can be performed simultaneously.

  In addition, for example, after removing the aqueous solution, an electrolyte that does not dissolve the material constituting the semiconductor wafer and its oxide is supplied into the hole or groove, and the processing tool left in the hole or groove is an anode. By causing an electrochemical reaction at the contact portion with the semiconductor wafer, an insulating film made of an oxide of the material constituting the semiconductor wafer is formed on the contact portion of the semiconductor wafer with the wiring made of the processing tool. Can be formed. Therefore, according to the above method, there is an effect that the wiring and the insulating film can be formed very easily.

  As described above, the processing method of the workpiece according to the present invention includes a processing tool having a surface made of a conductive material at least on the surface of the workpiece, and the workpiece is processed between the workpiece and the processing tool. Contact while supplying a processing liquid containing a solvent which is inert to the material constituting the product and a reactive substance which reacts with the oxide of the material constituting the workpiece and dissolves the oxide in the solvent. And by causing an electrochemical reaction at the contact portion with the workpiece using the processing tool as an anode, the contact portion with the processing tool in the workpiece is oxidized and dissolved in the aqueous solution. A method of processing the workpiece by moving the contact portion between the workpiece and the processing tool by moving the workpiece or the processing tool as the workpiece is melted.

  In addition, as described above, the method for processing a workpiece according to the present invention includes reacting a workpiece with a solvent inert to the material constituting the workpiece and an oxide of the material. The oxide is immersed in a treatment solution containing a reactive substance that dissolves in the solvent. In the treatment solution, at least the surface is made of a conductive material, and the additive is formed separately from the workpiece. By contacting with a tool and causing an electrochemical reaction at the contact portion with the workpiece using the processing tool as an anode, the contact portion of the workpiece with the processing tool is oxidized to form the aqueous solution. A method of processing the workpiece by moving the contact portion between the workpiece and the processing tool by moving the workpiece or the processing tool along with the melting of the workpiece. is there.

  In particular, the method for processing a workpiece according to the present invention includes, as described above, a workpiece made of at least one material selected from the group consisting of silicon, silicon carbide, and a semiconductor containing a group III-V element. Immersing in an aqueous solution containing hydrogen fluoride or fluoride ions, and in the aqueous solution, at least the surface is made of a conductive material, and is brought into contact with a processing tool formed separately from the workpiece; and By causing an electrochemical reaction at the contact portion with the workpiece using the processing tool as an anode, the contact portion with the processing tool in the workpiece is oxidized and dissolved in the aqueous solution. This is a method of processing the workpiece by moving the contact portion between the workpiece and the processing tool by moving the workpiece or the processing tool along with the dissolution of the workpiece.

  In each of the above methods, since the workpiece is processed by oxidizing and dissolving, there is no mechanical damage and thermal damage to the workpiece. Further, according to each of the above methods, the workpiece is locally and selectively dissolved (etched) in the contact portion with the processing tool and in the vicinity thereof, and the processing tool or the workpiece is removed. By moving, the contact portion between the workpiece and the processing tool can be moved in a desired direction, and the progress of processing (the degree of processing) can be easily grasped. Therefore, processing control is easy.

  Therefore, according to each of the above methods, there is an effect that the workpiece can be easily processed into a desired shape without causing mechanical damage and thermal damage.

  Further, the wiring forming method according to the present invention, as described above, fluorinates a workpiece made of at least one material selected from the group consisting of silicon, silicon carbide, and a semiconductor containing a group III-V element. Immersion in an aqueous solution containing hydrogen or fluoride ions, and in the aqueous solution, at least the surface is made of a conductive material and is brought into contact with a processing tool formed separately from the workpiece, and the processing tool The anode is used as an anode to cause an electrochemical reaction at the contact portion with the workpiece, thereby oxidizing the contact portion with the processing tool in the workpiece to dissolve it in the aqueous solution and dissolving the workpiece. Along with this, by moving the workpiece or processing tool to move the contact portion between the workpiece and the processing tool to form a hole or groove in the workpiece, in the hole or groove, The hole Is a method for directly left at least part of the processing tool used to form the groove.

  In addition, as described above, a method for manufacturing a semiconductor substrate according to the present invention includes a step of feeding a semiconductor wafer made of at least one material selected from the group consisting of silicon, silicon carbide, and a semiconductor containing a group III to V element. Immersion in an aqueous solution containing hydrogen fluoride or fluoride ions, and in the aqueous solution, at least the surface is made of a conductive material and is brought into contact with a processing tool formed separately from the semiconductor wafer, and the processing tool As an anode, an electrochemical reaction is caused at the contact portion with the semiconductor wafer, so that the contact portion with the processing tool in the semiconductor wafer is oxidized and dissolved in the aqueous solution. By moving the semiconductor wafer or the processing tool, the contact portion between the semiconductor wafer and the processing tool is moved so that holes or holes are formed in the semiconductor wafer. After forming the, in the hole or the groove, thereby forming a wiring while leaving at least a portion of the processing tool used to form the pores or grooves.

  Therefore, according to each of the above methods, the processing tool can be used as a wiring as it is, or a wiring can be formed by film growth using a catalyst on the surface of the processing tool. In addition to the effect described in the method, there is also an effect that a wiring having no defect or having fewer defects than the conventional one can be formed.

  In addition, as described above, after forming holes or grooves in a workpiece such as a semiconductor wafer, at least a part of the processing tool is left as it is in a processing part such as a hole or groove and used as a wiring. In addition, there is an effect that the formation of the groove and the formation of the wiring can be performed simultaneously.

[Embodiment 1]
An embodiment of the present invention will be described below with reference to FIGS.

  In the processing method for a workpiece according to the present embodiment, a workpiece having at least a surface (machined surface) made of a conductive material is placed on the surface of the workpiece between the workpiece and the workpiece. While supplying a treatment liquid containing a solvent inert to the material constituting the workpiece and a reactive substance that reacts with the oxide of the material constituting the workpiece and dissolves the oxide in the solvent. Contacting and causing an electrochemical reaction at the contact portion with the workpiece using the processing tool as an anode, the contact portion of the workpiece with the processing tool is oxidized and dissolved in the aqueous solution. A method of processing the workpiece by moving the contact portion between the workpiece and the processing tool by moving the workpiece or the processing tool as the workpiece is melted.

  More specifically, in the processing method of the workpiece according to the present embodiment, the workpiece is reacted with a solvent inert to the material constituting the workpiece and an oxide of the material. And immersed in a treatment liquid containing a reactive substance that dissolves the oxide in the solvent, and at least the surface is made of a conductive material in the treatment liquid, and is formed separately from the workpiece. Contacting with the processing tool and causing the electrochemical reaction at the contact portion with the workpiece using the processing tool as an anode, the contact portion of the workpiece with the processing tool is oxidized and the aqueous solution A method of processing the workpiece by moving the contact portion between the workpiece and the processing tool by moving the workpiece or the processing tool along with the dissolution of the workpiece. It is.

  The workpiece to be applied to the processing method according to the present embodiment is not particularly limited as long as it has a portion made of a material subjected to an oxidation reaction. It is desirable that part or all be made of at least one material selected from the group consisting of silicon, silicon carbide, and a semiconductor containing a group III-V element. Although it does not specifically limit as a semiconductor containing a III-V group element, For example, GaN etc. are mentioned.

  In the treatment liquid used for processing the workpiece, as described above, the solvent which is inert to the material constituting the workpiece and the oxide of the material reacts with the oxide to form the solvent. A treatment liquid containing a reactive substance to be dissolved in is used.

  The reactive substance is not particularly limited as long as it can react with the oxide of the material and dissolve the oxide in the solvent. Examples of the reactive substance include hydrogen fluoride and fluoride ions.

  The solvent is inert to the material constituting the workpiece and can dissolve the oxide of the material constituting the workpiece in the presence of the reactive substance. If it is a thing, it will not specifically limit. As the solvent, for example, water is used.

  The treatment liquid may consist only of the solvent and the reactive substance, and may contain other substances other than the solvent and the reactive substance, such as an oxidizing agent, as necessary.

  When the processing liquid contains an oxidizing agent, the processing speed of the workpiece can be increased.

  The oxidizing agent is not particularly limited as long as it can oxidize the material constituting the workpiece. Specifically, for example, peroxides; peroxo acids and salts thereof Ozone, oxygen, trivalent iron ions, and the like.

The peroxide is not particularly limited as long as it contains a peroxide ion O ₂ ²⁻ and generates H ₂ O ₂ when acidified. For example, hydrogen peroxide, sodium peroxide, etc. Is mentioned.

  The peroxo acid is not particularly limited as long as it is an inorganic acid having a —O—O— bond, and examples thereof include peroxodisulfuric acid and sodium peroxodisulfate.

  Examples of the trivalent iron ion include iron (III) sulfate and iron (III) nitrate.

  Furthermore, the treatment liquid may contain substances other than those described above within a range that does not inhibit a series of reactions in which the oxidation reaction of the workpiece and the oxide of the material are dissolved in the solvent.

  The method for preparing the treatment liquid is not particularly limited, and each component used in the treatment liquid containing a reactive substance, a solvent, and, if necessary, the oxidizing agent may be added and mixed. For example, an oxidizing agent or a reactive substance may be mixed with the remaining components in a state of being dissolved in a solvent in advance, such as hydrogen peroxide solution or hydrofluoric acid (hydrofluoric acid). That is, the solvent may be added separately from the reactive substance alone or in a state where other substances such as an oxidizing agent are dissolved. For example, hydrofluoric acid (hydrofluoric acid) As described above, a reactive substance may be dissolved in advance.

  The mixing method of said each component is not specifically limited, A commercially available stirring and mixing apparatus can be used.

  In addition, the amount and concentration of the reactive substance used in the treatment liquid, and the amount and concentration of the oxidizing agent used as necessary may be appropriately determined according to the processing area, processing form, etc. The liquid is not particularly limited as long as it contains an oxidizing agent and a reactive substance in a sufficient amount for the oxidation reaction. When the workpiece is silicon, the higher the concentration of the reactive substance (hydrogen fluoride) is desirable in that the processing speed can be increased, specifically, 20 mol / l or more, preferable.

  Further, the temperature of the treatment liquid (treatment temperature) is not particularly limited, and the treatment can be performed at normal pressure and normal temperature (room temperature). However, if the temperature is increased, the processing speed can be increased.

  When the workpiece is a workpiece made of silicon, such as a silicon substrate, it is preferable to use hydrofluoric acid as the treatment liquid, but it may be an aqueous solution of other reactive substances. Good.

  Further, the processing tool used in the present embodiment is not particularly limited as long as at least the surface (processed surface) is made of a conductive material.

  According to this embodiment, the processing tool is connected to a potential control device (current control device) capable of electrochemically controlling the potential, and an electrochemical reaction occurs at the contact portion with the workpiece using the processing tool as an anode. As a result, the workpiece can be oxidized without using an oxidant, whereby the workpiece can be processed. This is because electrons are deprived from the workpiece in contact with the processing tool by the effect of the electrochemical positive potential.

  In other words, when a processing tool that is an anode is brought into contact with a workpiece, an electrochemical reaction occurs at the contact portion (contact interface), that is, with the movement of electrons from the workpiece to the processing tool, and with the movement of the electrons. The chemical reaction that takes place occurs and the work piece in the contact area is oxidized.

  As the processing tool, a processing tool formed by processing a conductive material into a desired shape can be used. In addition, as the processing tool, a base made of a non-conductive material and a surface coated with a conductive material may be used.

  As the conductive material used for the processing tool, for example, carbon, metal, or the like can be used. As long as it has conductivity, it may not have a catalytic action. However, the conductive material used for the processing tool is preferably a material having a catalytic action in the oxidation reaction of the workpiece because the processing speed of the workpiece can be increased.

  In this way, by applying an electric potential to the catalyst and making the surface of the catalyst oxidative by the electric potential, an effect that can dramatically increase the function of the catalyst can be expected, and the treatment liquid contains an oxidizing agent. Therefore, an effect of dramatically increasing the effect of the oxidizing agent in the treatment liquid is expected.

  Accordingly, the processing tool may be a processing tool obtained by processing a catalyst into a desired shape, or a substrate in which the catalyst is coated on a surface made of a metal such as carbon, resin, or iron may be used. Good.

  The processing tool or the substrate used in the processing tool is not particularly limited, and examples thereof include a wire or a blade-like material made of carbon fiber, iron, steel, silicon carbide, or the like. .

  The catalyst is not particularly limited as long as it is a material that acts as a catalyst in the oxidation reaction of the workpiece, and examples thereof include platinum, gold, iridium, and alloys thereof.

  The method for coating the surface of the substrate with the conductive material is not particularly limited, and various conventionally known coating methods such as coating and plating can be used.

  Further, the form (shape) of the processing tool is not particularly limited, and may be appropriately determined according to the processing form or the processing shape. As the form of the processing tool, for example, a processing tool having a linear or dotted processing surface such as a wire, a blade, or a needle is preferably used.

  The wire may be a straight wire, or may be a net formed by combining a number of wires. By using a net-like wire in this way, a large number of silicon can be cut simultaneously.

  In addition, as the needle, a single needle may be used alone, or a collection of needles such as a so-called Kenzan.

  Similarly, the blade may also be a single blade, and a large number of blades may be arranged in parallel.

  Examples of the potential control device (current control device) used in the present embodiment include a potentiostat or a galvanostat (current control).

  According to the present embodiment, a processing tool connected to a working electrode terminal in a potential control device such as a potentiostat capable of electrochemically controlling a potential is used as an anode, and the processing tool is brought into contact with a workpiece. As a result, an electrochemical reaction can be caused in the contact portion of the workpiece with the processing tool to be oxidized.

  In the present embodiment, as a reference electrode connected to the reference electrode terminal in the potential control device (current control device), for example, a silver silver electrode, a saturated calomel electrode, or the like is used.

  Moreover, as a counter electrode connected to a counter electrode terminal, a platinum wire, a platinum plate, etc. are used, for example.

  In the present embodiment, the workpiece is immersed in the processing solution tank in a state where the processing tool connected to the working electrode terminal is in contact, and a voltage is applied between the working electrode and the reference electrode.

  In the present embodiment, the potential applied to the processing tool by the potential control device (current control device) is not particularly limited as long as the workpiece can be oxidized, For example, in the range of +0 to +4 V with respect to the reference electrode, it is preferable from the viewpoint of processing speed and power consumption. For example, as in the example described later, when the above-described silver electroluminescent electrode is used as a reference electrode, a potential of +4 V is applied to the reference electrode. In this case, the potential may be between +0 and +4 V with respect to the reference electrode, but the processing speed can be increased as the potential is increased.

  In the present embodiment, examples of the processing form of the workpiece include formation of holes and grooves in the workpiece, cutting of the workpiece, and the like. According to the present embodiment, the workpiece is brought into contact with the processing tool in the processing liquid, and an electrochemical reaction is caused at the contact portion with the workpiece using the processing tool as an anode. The contact portion of the workpiece with the processing tool can be oxidized and dissolved.

  In particular, when the workpiece is a semiconductor containing silicon, silicon carbide, or a group III-V element, dissolution of the workpiece under the above conditions is only at the portion in contact with the conductive material (processing tool). Occur.

  Note that the contact width (for example, blade thickness, blade span, wire diameter, needle diameter, etc.) of the conductive material (processing tool) with the workpiece is appropriately set to a desired size according to the processing shape of the workpiece. There is no particular limitation.

  According to the present embodiment, for example, a thin wire made of the conductive material (for example, the catalyst wire) or a blade-like processing tool is immersed in the processing liquid in a state of being in contact with silicon, and the processing tool is anoded. As a result of causing an electrochemical reaction at the contact portion with silicon, the contact portion with the processing tool (for example, the catalyst wire) and silicon in the immediate vicinity thereof are locally and selectively dissolved (etched). At this time, when the silicon or the workpiece is moved by an external force or moved naturally by gravity or the like, both contact portions are moved, and the contact portion is used as a base point. It is possible to form a groove in silicon (occurrence of cut) or cut (cut out a silicon ingot or cut a silicon wafer from a silicon ingot).

  FIGS. 3A and 3B and FIGS. 4A to 4C show an example of a method of cutting a workpiece using various processing tools.

  3A and 3B show a state in which small-diameter silicon wafers (hereinafter referred to as silicon chips) 16... Are cut out from the large-diameter silicon wafer 15 using a net-like wire 20.

  First, as shown in FIG. 3A, a net-like wire 20 as a processing tool and a silicon wafer 15 as a workpiece are prepared. The mesh wire 20 may be a combination of a plurality of wires arranged in a mesh shape, or may be formed in a mesh shape. The net-like wire 20 has an opening diameter formed in the size of the silicon chip 16 to be cut out.

  The net-like wire 20 is positioned on the silicon wafer 15 so as to increase the number of silicon chips 16 to be cut out, and is immersed in the processing liquid. Next, the mesh wire 20 is connected to a working electrode terminal of a potential control device (current control device) (not shown) to cause an electrochemical reaction at the contact portion with the silicon wafer 15 using the mesh wire 20 as an anode. As a result, the contact portion of the silicon wafer 15 with the mesh wire 20 is oxidized and dissolved, and finally the silicon wafer 15 is divided into a plurality of silicon chips 16 as shown in FIG.

  4A to 4C show a state in which individual silicon chips 16 are cut out from the silicon wafer 15 using a processing tool 30 having a plurality of blades 32 and 32 provided in parallel on the substrate 31. Show.

  First, as shown in FIG. 4A, the processing tool 30 and a silicon wafer 15 as a workpiece are prepared. The fixed surfaces of the blades 32 and 32 in the substrate 31 have, for example, the same area as or larger than the cut surface 15a of the silicon wafer 15, and the blade span of each blade 32 is the same as or equal to the cut surface 15a of the silicon wafer 15. It has the above length. Further, the height of each blade 32 from the surface of the substrate 31 is equal to or higher than the thickness of the silicon wafer 15. The interval between the blades 32 and 32 is set in accordance with the size (width) of the silicon chip 16 to be cut out. Each blade 32 only needs to have a processed surface formed of a conductive material regardless of the presence or absence of a catalyst, but may itself be formed of a catalyst or may have a surface coated with a catalyst. .

  The processing tool 30 is placed on the silicon wafer 15 so that each blade 32 contacts the silicon wafer 15, and is immersed in the processing liquid. Next, each blade 32 is connected to a working electrode terminal of a potential control device (current control device) (not shown), and an electrochemical reaction is caused at the contact portion with the silicon wafer 15 by using each blade 32 as an anode. The contact portions of the wafer 15 with the blades 32 are oxidized and dissolved. Each blade 32 becomes a weight of the substrate 31 that fixes each blade 32, and gradually moves in the direction of gravity as the silicon wafer 15 is oxidized and dissolved. Next, as shown in FIG. 4B, after each blade 32 reaches the bottom surface of the silicon wafer 15, the processing tool 30 is pulled up to remove the processing tool 30 from the silicon wafer 15 as shown in FIG. 4C. When separated, silicon chips 16 formed by dividing the silicon wafer 15 into a plurality of pieces can be obtained.

  Hereinafter, an example of a chemical reaction in each step in the processing method will be described by taking as an example the case of using silicon as the material of the workpiece.

  First, as described above, a wire-like or blade-like processing tool is brought into an aqueous solution (treatment liquid) containing hydrogen fluoride in a state where it is in contact with, for example, a location where a groove is to be formed on silicon or a location where silicon is desired to be cut. Immerse.

As described above, when the workpiece is immersed in the processing liquid and the processing tool that is set as the anode is brought into contact with the silicon, a contact portion with the processing tool is caused by an electrochemical positive potential effect. As a result, electrons are removed from the silicon, and as a result, the silicon in contact with the catalyst is oxidized. Oxidized silicon reacts with hydrogen fluoride in the treatment liquid to dissolve as water-soluble hexafluorosilicate ions (SiF ₆ ²⁻ ). At this time, at the counter electrode, the following formula 2H ⁺ + 2e ⁻ → H ₂
As shown by the following, a reduction reaction of hydrogen ions occurs. Moreover, the oxidation dissolution reaction of silicon at this time is expressed by the following formula: Si + 2H ₂ O + 4h ⁺ → SiO ₂ + 4H ⁺
SiO ₂ + 6HF → SiF ₆ ²⁻ + 2H ₂ O + 2H ⁺
Indicated by

  As described above, according to the present embodiment, since silicon etching occurs at the contact portion between the catalyst and silicon in the processing tool, the processing tool (in this case) is moved by moving the processing tool or silicon. Can control the degree of processing, that is, whether a groove of a certain depth is formed or cut, and the processing direction.

  Further, according to the present invention, as described above, since it is only necessary to bring the processing tool to which a potential is applied into contact with silicon in the processing liquid, the conventional technique has been used to perform wafer cutting by mechanical polishing cutting with a wire saw. Compared with, the processing cost including the equipment cost can be greatly reduced. Furthermore, since no defect occurs on the wafer, it is extremely advantageous in device applications. Further, since silicon melts only at the contact portion with the processing tool, there are advantages that the cut white portion is overwhelmingly reduced and that an abrasive cutting step is not required.

  Conventionally, as a processing method using a chemical reaction including the applicant of the present application, a metal having a catalytic function of a reduction reaction with respect to an oxidizing agent is deposited or screen printed on the surface of a semiconductor crystal substrate such as a silicon substrate. A method of forming a porous layer around the metal thin film (electrode) by baked later to form a metal thin film (electrode) and immersing the semiconductor crystal substrate in an aqueous solution containing an oxidizing agent (for example, Patent Document 8) And Non-Patent Document 6) have been proposed. This method is specialized for the method of forming a porous layer around the metal thin film, and at first glance it is similar to the present invention, but the porous silicon is formed around the metal thin film (electrode). Specifically, it occurs in a region surrounded by a metal thin film (electrode).

  On the other hand, according to the present invention, when a large number of wires are combined to form a net, silicon is oxidized and dissolved at the contact portion between the net-like wire and silicon.

  As a result of intensive studies in the process of completing the present invention by the inventors of the present application, the inventors of the present application have come to the following conclusions. That is, when a metal thin film (electrode) is formed on the surface of a semiconductor crystal substrate such as a silicon substrate and the semiconductor crystal substrate is immersed in an aqueous solution containing an oxidant as in the conventional case, the metal electrode is in contact with silicon. In the part, metal and silicon are mixed together and are so close that a clear interface cannot be defined. For this reason, the processing liquid is not supplied to the contact portion, and silicon is made porous and roughened around the metal thin film (electrode). On the other hand, according to the present invention, instead of the metal thin film (electrode) integrated with the workpiece such as silicon as described above, a processing tool provided separately from the workpiece is used, As described above, the processing liquid containing the reactive substance exists between the surface of the workpiece and the processing tool, so that the workpiece is selectively oxidized and dissolved at the contact portion of the workpiece with the catalyst. In addition, as described above, the processing mode (degree of processing) and the processing direction can be easily controlled by moving the processing tool or silicon.

  As described above, according to the present embodiment, a fine wire (preferably a catalyst wire) to which a potential is applied is brought into contact with, for example, a single crystal silicon or polycrystalline silicon ingot in the treatment liquid, and the contact is made. By causing the dissolution reaction only at the portion, the wafer can be cut (sliced) without waste.

  That is, in the present invention, the time required for processing the workpiece, that is, the processing time is not particularly limited, and the contact time between the workpiece and the processing tool is appropriately set so as to obtain a desired processing form. Adjust it.

  When silicon is used as the workpiece, the processing speed at which silicon can be cut is approximately 1 mm / day.

  In addition, while wafer cutting with a wire saw was a mechanical polishing cutting method, the present invention is a chemical reaction utilizing oxidation of a workpiece. For example, (1) there is no need for mechanical polishing cutting , Equipment cost is overwhelmingly low, (2) very few white cuts (can be cut with ultra-fine wire, and in principle can be cut with its line width), (3) crystal defects due to damage during cutting It is advantageous in post-processing and device characteristics. (4) Since it does not require a mechanical polishing and cutting process, it is easy to manufacture polycrystalline thin wafers that are easy to break. (5) Basically to be processed. It can be processed by simply immersing an object in a solution and bringing a processing tool to which a potential is applied into contact, and it has various effects such as easy scale-up. ) Especially when emphasizing Although it has to speed described above it is fast enough to a separatory used for dicing the wafer.

  That is, the thickness of a general wafer is 0.6 mm at most. For example, a wire-like mesh is used as a processing tool, and a plurality of portions are cut at a time, thereby suppressing processing speed and deterioration of characteristics. Both can be fully satisfied. In addition, by using the chemical processing method according to the present embodiment using an oxidation reaction, crystal defects due to damage at the time of processing do not occur, and deterioration of characteristics can be prevented, for example, It is obvious from various documents using chemical processing methods such as Patent Documents 4 to 8 and Non-Patent Documents 1 to 7, and it is not necessary to discuss them.

  Further, according to the present embodiment, it is possible to apply a potential by immersing a large number of substrates at the same time in the same processing solution. For this reason, since it is rich in mass productivity and does not require an expensive apparatus and labor, the said processing can be performed cheaply.

  In recent years, as shown in Patent Document 9 and Non-Patent Document 8, as a chemical processing method other than a chemical processing method using an oxidation reaction, a halogen which does not normally have solubility in a workpiece. The workpiece is placed in a treatment solution in which molecules containing benzene are dissolved, and the catalyst is brought into contact with or in close proximity to the processed surface of the workpiece to generate halogen radicals on the surface of the catalyst. Methods for eluting halogen compounds generated by chemical reaction with surface atoms have been proposed, but the processing methods described in Patent Document 9 and Non-Patent Document 8 are limited by the generation rate of halogen radicals, and the rate is It is considered that it is determined by the catalyst material and the processing liquid (specifically, the concentration of the halogen-containing molecule in the processing liquid), and it is not easy to control the processing speed during the processing. On the other hand, according to the present invention, for example, the machining speed can be easily controlled by changing the potential of the machining tool by the above-described potential control device.

  In the above description, the case where silicon is used as a workpiece has been described as an example. However, as described above, the workpiece may be a material other than silicon.

  For example, Non-Patent Document 7 discloses that etching using a chemical reaction of silicon carbide is possible by using a thin film of platinum deposited on silicon as a catalyst. Patent Document 7 discloses a chemical reaction of a semiconductor containing a group III-V element. Therefore, from these documents or other known documents, a combination of a workpiece and a reactive substance that dissolves the oxide of the workpiece, a combination of a workpiece and a catalyst, or a necessity By selecting the combination with the oxidizing agent for the workpiece to be used accordingly, the same effect as when silicon is used as the workpiece can be obtained for workpieces other than silicon.

  Further, in the above description, the case where the processing tool is immersed in the processing liquid in a state of being in contact with the processing portion of the workpiece is described as an example, but the present invention is limited to this. Instead, the workpiece may be immersed in the processing solution and then contacted with the processing tool, or the workpiece may be contacted with the processing tool while being immersed in the processing solution. In this case, the contact of the processing tool with the workpiece may be before or after the immersion of the workpiece into the processing liquid.

  As described above, the method of immersing the workpiece in the processing liquid and bringing it into contact with the processing tool allows the processing liquid to be supplied between the workpiece and the processing tool easily and without waste. However, the present invention is not limited to this, and it is only necessary to supply a processing liquid between the workpiece and the processing tool, and the workpiece is placed in the processing liquid. It is not always necessary to immerse.

  In the above description, the method of cutting the workpiece is mainly described. However, the processing method according to the present embodiment is not limited to the cutting of the workpiece. Hereinafter, as a processing method according to the present embodiment, a method for drilling a workpiece is described, and a wiring forming method using the drilling method is described.

  5 (a) to 5 (d) show that the silicon wafer 15 penetrates the silicon wafer 15 using a processing tool 40 provided with a needle-like conductive material (hereinafter simply referred to as "needle") 41 at the tip. It shows how the through wiring is formed.

  First, as shown in FIG. 5A, the processing tool 40 and a silicon wafer 15 as a workpiece are prepared. In the present embodiment, the needle length of the needle 41 is set to be larger than the thickness of the silicon wafer 15. The needle diameter of the needle 41 is set according to the wiring diameter to be formed. The needle 41 only needs to have a processed surface formed of a conductive material regardless of the presence or absence of a catalyst, but may itself be formed of a catalyst or may be coated with a catalyst. .

  The processing tool 40 connects the needle 41 to a working electrode terminal of a potential control device (current control device) (not shown), and presses the silicon wafer 15 in a processing solution as shown in FIG. The silicon wafer 15 is oxidized and dissolved by causing an electrochemical reaction at the contact portion with the silicon wafer 15 using the needle 41 as an anode. At this time, as shown in FIG. 5B, when the processing tool 40 is pulled up after the needle 41 reaches the bottom surface of the silicon wafer 15 to separate the processing tool 40 from the silicon wafer 15, the silicon wafer 15 is perforated. Can be processed.

  In the present embodiment, after the needle 41 reaches the bottom surface of the silicon wafer 15, the needle 41 is formed on the silicon wafer 15 formed by the needle 41 as shown in FIGS. 5B and 5C. The needle 41 exposed from the silicon wafer 15 while being embedded in the hole 17 is cut by, for example, a laser, and the needle 41 remains in the silicon wafer 15 as shown in FIG. 5D. Thus, a through wiring penetrating the silicon wafer 15 is formed in the silicon wafer 15.

  The wiring can be used for a transistor having a vertical MOS structure, for example.

  In the above description, the needle 41 is cut with a laser. However, the present invention is not limited to this, and the cutting method of the conductive material (catalyst) serving as the needle 41, that is, the wiring, is as follows. It is not particularly limited.

  5A to 5D, the case where the through wire is formed using the processing tool 40 having the needle 41 provided at the tip as the processing tool has been described as an example. Is not limited to this.

  For example, a groove is formed in the silicon wafer 15 using the net-like wire 20 shown in FIG. 3A, the processing tool 30 shown in FIG. 4A, or a processing tool such as a wire formed in a desired wiring shape. After forming, the in-groove wiring may be formed by leaving the mesh-like wire 20 or the blade 32, or other shapes of wires in the formed groove.

  5A to 5D, a wire is used in place of the processing tool 40, and while the silicon wafer 15 is oxidized and dissolved, the wire is contacted and moved in the wiring extending direction of the silicon wafer to perform drilling and wiring. By performing the formation at the same time, the embedded wiring extending in the in-plane direction or the normal direction with respect to the substrate surface may be formed.

  As described above, after a hole or groove is formed in the workpiece, at least a part of the processing tool is left as it is in a processing site such as a hole or groove after processing, so that the remaining processing tool, for example, a wire Etc. can be used as the wiring material, so that the formation of holes and grooves and the formation of wiring can be performed simultaneously. Further, the conductive material (catalyst) on the surface of the processing tool left in the processing site in this way can also be used as a catalyst for the wiring formation process (film growth from the conductive material).

  When a wiring material is provided inside the hole after a hole is provided in the substrate by a perforation technique using metal particles, it is conceivable that the wiring material is deposited inside the hole by a method such as plating or vapor deposition. However, the wiring formed by such a method has a structure in which fine grains are gathered and the number of defects increases.

  However, according to the present embodiment, for example, a metal needle having no defect or few defects can be used as the needle 41. By using the needle 41 as a wiring while remaining in the hole 17, there is no defect. A wiring having no or few defects can be obtained.

  Also, in the prior art, when a wiring material is arranged in the hole after drilling with metal particles, in order to obtain a wiring that penetrates the substrate, the drilling is stopped before the metal particles penetrate the substrate. A process of depositing the wiring material on the substrate and polishing and removing the substrate material from the back surface of the substrate to the bottom of the hole is required.

  However, in the present embodiment, as described above, for example, the needle 17 is used to form the hole 17 penetrating the substrate, for example, a semiconductor wafer such as the silicon wafer 15, and the needle 41 is left in the hole 17. Since the through wiring is obtained, the wiring material deposition and substrate polishing removal steps are not required.

  Therefore, according to the present embodiment, after forming a hole or groove in the workpiece as described above, by leaving at least a part of the processing tool as it is in the processing site such as the hole or groove after processing, A wiring board can be easily manufactured, and wiring with few defects can be formed.

  Further, according to the present embodiment, when the hole 17 is formed in the semiconductor wafer such as the silicon wafer 15 using the acicular catalyst as described above, and the catalyst (processing tool) is left in the hole 17. Then, after removing the aqueous solution by washing or the like, a semiconductor material (for example, silicon) constituting the semiconductor wafer such as the silicon wafer 15 and an electrolytic solution that does not dissolve the oxide are supplied to the holes 17, and in the electrolytic solution, By causing an electrochemical reaction at the contact portion with the semiconductor wafer such as the silicon wafer 15 by using the catalyst (processing tool) as an anode, the semiconductor material on the inner wall of the hole 17 is oxidized, and a wiring made of the catalyst is formed. An oxide film such as a silicon oxide film that functions as a necessary insulating film between the semiconductor material and the semiconductor material can be formed in a contact portion with the wiring made of the processing tool in the semiconductor wafer.

  Therefore, the above processing method is particularly suitable for manufacturing a silicon substrate among semiconductor substrates (wiring substrates).

  In addition, as said electrolyte solution, it is inert with respect to the semiconductor material (for example, silicon) which comprises semiconductor wafers, such as the said silicon wafer 15, and its oxide (namely, the said semiconductor material and its oxide are not melt | dissolved), Although it will not specifically limit if it is an electroconductive solution, The electroconductive aqueous solution is used suitably. The aqueous solution is not particularly limited, and may be, for example, an aqueous solution of a general electrolyte such as sulfuric acid, or an aqueous solution of the oxidizing agent or an aqueous solution containing the oxidizing agent. The electrolyte is not particularly limited as long as it does not dissolve the semiconductor material and its oxide when formed into an aqueous solution (electrolytic solution), but the silicon oxide film contains the oxidizing solution containing an oxidizing agent. It is possible to increase the processing speed for forming the oxide film. In addition, as the oxidizing agent in this case, for example, the oxidizing agents exemplified above can be used.

  Further, the potential applied to the catalyst (processing tool) is not particularly limited as long as the semiconductor wafer can be oxidized, but as described above, for example, with respect to the reference electrode The range of +0 to +4 V is preferable from the viewpoint of processing speed and power consumption, and the processing speed can be increased as the electric potential is increased.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, this invention is not limited to this.

[Example 1]
FIG. 1 is a perspective view illustrating a schematic configuration of an apparatus 50 used for bringing a processing tool into contact with a workpiece used in the present embodiment. FIG. 2 is a cross-sectional view showing a state in which a workpiece incorporated in the apparatus 50 shown in FIG. 1 is immersed in an etching solution tank (processing solution tank) in a cross section of the etching solution tank.

  In this example, in order to conduct a simple experiment, a 500 ml beaker 7 made of Teflon (registered trademark) is used as the etching solution tank as shown in FIG. Got ready.

  First, as shown in FIG. 1, through holes 5a, 5a, 5b, and 5b for inserting the support beam 6 and the sample 1 as a workpiece are provided on the peripheral wall of a cup 5 made of polypropylene. The support beam 6 and the sample 1 were inserted into 5a, 5a, 5b, and 5b so that both ends of the sample 1 and both ends of the support beam 6 protruded from the peripheral wall of the cup 5, respectively. The thickness and strength of the cup 5 are not particularly limited as long as the sample 1 can be stably supported with a weight (load) applied to the sample 1 as described later. Absent. In the present embodiment, a commercially available disposable cup (manufactured by As One Co., Ltd., “dispo cup (trade name)” made of polypropylene, thickness 0.5 mm) was used as the cup 5.

  In this example, a silicon wafer (boron-doped, resistivity 7 to 13 Ωcm, thickness 625 μm, manufactured by ELECTRONICS AND MATERIALS CORPORATION) with a (100) crystal plane exposed was cut into 10 mm length × 70 mm width as sample 1. Using. Further, the support beam 6 was made of disposable chopsticks.

  Next, the cup 5 is arranged so that the support beam 6 is positioned above the sample 1, and ring-shaped wires 2 and 2 (processing tools) are respectively attached to both ends of the sample 1 protruding from the cup 5. The support plate 4 that supports the weight 3 was hooked on the lower ends of the ring-shaped wires 2 and 2. Thereafter, another wire 9a for connecting the wires 2 and 2 is connected to the wires 2 and 2, and another wire 9b is connected to the wires 2 and 2 near the center of the wire 9a. A device 50 shown in FIG. 1 was assembled, in which the Y-shaped wire 9 composed of the wires 9a and 9b, which was the working electrode terminal, was connected. As shown in FIG. 1, the sample 1 was arranged such that the vertical direction was the gravitational direction and the surface in the thickness direction was the upper surface (the contact surface with the wires 2 and 2).

  The support plate 4 is provided through the weight 3, and the support plate 4 is placed in the ring of the wires 2 and 2 and is hung to apply a weight (load) to the wires 2 and 2. Can do.

  In this example, a platinum wire (purity 99.98%, manufactured by Niraco Co., Ltd.) having a wire diameter of 0.05 mm, a wire length of 6 cm, and a weight of 0.003 g was used as the wire 2 used for the above-described processing. The wire 9a was a platinum wire (purity 99.98%, manufactured by Nilaco Corporation) having a wire diameter of 0.05 mm, a wire length of 6 cm, and a weight of 0.003 g. As the wire 9b, a platinum wire (purity 99.98%, manufactured by Nilaco Corporation) having a wire diameter of 0.1 mm, a wire length of 12 cm, and a weight of 0.025 g was used.

  The weight 3 was a Teflon-coated rotor (manufactured by As One Co., Ltd.), and its mass was 30 g. The support plate 4 was a 0.60 g polyethylene plate.

  In this embodiment, the apparatus 50 shown in FIG. 1 obtained by fixing the processing position of the sample 1 by hooking the wires 2 and 2 on the sample 1 in the state where the weight is applied is shown in FIG. As shown, the support beam 6 in the apparatus 50 was placed in the 500 ml beaker 7 by placing it on the edge of a 500 ml beaker 7 made of Teflon.

  Next, the capillary 10 at the tip of the salt bridge connected to the reference electrode and the platinum wire 11 for the counter electrode were installed in the 500 ml beaker 7. The capillary tube 10 is filled with agar, and the salt bridge is filled with a saturated aqueous potassium chloride solution. A silver-silver chloride electrode was used as the reference electrode.

  Next, a potentiostat 12 is prepared, the wire 9 is connected to the working electrode terminal of the potentiostat 12, the reference electrode (silver silver chloride electrode) connected to the capillary 10 is connected to the reference electrode terminal of the potentiostat 12, and the above The platinum wire 11 was connected to the counter electrode terminal of the potentiostat 12.

  As the potentiostat 12, “POTENTIOSTAT NPOT-2501” (trade name, manufactured by NIKKO KEISOKU) was used.

  Next, 300 ml of 50 wt% hydrofluoric acid is added to the 500 ml beaker 7 as a treatment liquid 8 (etching liquid) for etching, and the potential of the wires 2 and 2 with respect to the reference electrode is set to +4 V using the potentiostat 12. The sample 1 was left in a state immersed in the treatment liquid 8.

  As described above, after immersing the sample 1 in the treatment liquid 8 and setting the potential of the wires 2 and 2 to the reference electrode to +4 V for one day, the apparatus 50 shown in FIG. And air dried in air.

  Next, after removing the wires 2 and 2 from the sample 1, the contact portion of the sample 1 with the wire 2 is placed on a scanning electron microscope (“S-5000 (trade name)” manufactured by Hitachi High-Technology). I took a picture. The result is shown in FIG.

  FIG. 6 is a scanning electron micrograph of the groove 1a formed in the contact portion (processed portion) with the wire 2 in the sample 1 used in this example. As shown in FIG. 6, the groove 1a was formed in the sample 1 to a depth of 1050 μm. The width of the groove 1a was about 50 μm at the processing end point and about 60 μm at the processing start point.

  As described above, according to this example, the sample 1 can be easily processed into a desired shape without causing mechanical damage and thermal damage to the sample 1, and at a low cost. In addition, it is possible to provide a cutting method with less waste of energy and resources.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. That is, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.

  The processing method of the workpiece according to the present invention is as follows: (1) No mechanical polishing cutting is required, and the equipment cost is overwhelmingly low. (2) Cutting white is extremely low (can be cut with an ultra fine wire, and in principle. (3) No crystal defects due to damage at the time of cutting occur, which is advantageous in post-processing steps and device characteristics, (4) Since no mechanical polishing cutting step is required, Easy to produce polycrystalline thin wafers that are easy to break. (5) Basically, it is only necessary to immerse the work piece in the solution and bring the work tool to which a potential is applied into contact, and it is easy to scale up. It has various effects such as. For this reason, the processing method of the workpiece is a method of cutting a semiconductor wafer from an ingot made of a semiconductor material such as a silicon ingot, or a method of dividing (dicing) a wafer having an integrated circuit formed on the surface into individual chips. Can be preferably used. Moreover, the processing method of the workpiece concerning this invention can be used suitably for formation of wiring, or manufacture of a semiconductor substrate (wiring board).

It is a perspective view which shows schematic structure of the apparatus used in order to contact a workpiece with the workpiece used in Example 1. FIG. It is sectional drawing which shows the state which the workpiece incorporated in the apparatus shown in FIG. 1 was immersed in the etching liquid tank in the cross section of this etching liquid tank. (A) * (b) is a figure which shows an example of the cutting method of the workpiece concerning one Embodiment of this invention. (A)-(c) is a figure which shows another example of the cutting method of the to-be-processed object concerning one Embodiment of this invention. (A)-(d) is a figure which shows an example of the boring of a workpiece and the wiring formation method concerning one Embodiment of this invention. It is a figure which shows the scanning electron micrograph of the groove | channel formed in the contact part with a wire in the sample used in Example 1. FIG.

Explanation of symbols

1 Sample (workpiece)
2 Wire (processing tool)
3 Weight 4 Support plate 5 Cup 5a Through hole 5b Through hole 6 Support beam 7 500 ml beaker 8 Treatment liquid 9 Wire 9a Wire 9b Wire 10 Capillary 11 Platinum wire 12 Potentiostat (potential control device)
15 Silicon wafer 15a Cutting surface 16 Silicon chip 17 Hole 20 Reticulated wire 30 Processing tool 31 Substrate 32 Blade 40 Processing tool 41 Conductive material 41 Needle 50 Device

Claims (12)

  A workpiece made of at least one material selected from the group consisting of silicon, silicon carbide, and a semiconductor containing a group III-V element is immersed in an aqueous solution containing hydrogen fluoride or fluoride ions, Then, at least the surface is made of a conductive material and is brought into contact with a processing tool formed separately from the workpiece, and an electrochemical reaction is performed at the contact portion with the workpiece using the processing tool as an anode. By causing the workpiece to oxidize the contact portion of the workpiece with the processing tool and dissolve it in the aqueous solution, the workpiece or the processing tool is moved along with the dissolution of the workpiece. A method of processing a workpiece, wherein the workpiece is processed by moving a contact portion between the workpiece and a processing tool.   A workpiece made of a conductive material at least on the surface of the workpiece, a solvent inert to the material constituting the workpiece, between the workpiece and the workpiece, and the workpiece And contact with the workpiece using the processing tool as an anode while supplying a treatment liquid containing a reactive substance that reacts with the oxide of the material constituting the material and dissolves the oxide in the solvent. By causing an electrochemical reaction in the portion, the contact portion of the workpiece with the processing tool is oxidized and dissolved in the aqueous solution, and the workpiece or processing tool is dissolved along with the dissolution of the workpiece. A method of processing a workpiece, wherein the workpiece is processed by moving a contact portion between the workpiece and a processing tool by moving the workpiece.   In a treatment liquid containing a workpiece, a solvent inert to the material constituting the workpiece, and a reactive substance that reacts with the oxide of the material to dissolve the oxide in the solvent. Immersion, and in the treatment liquid, at least the surface is made of a conductive material, is brought into contact with a processing tool formed separately from the workpiece, and the processing tool is used as an anode with the workpiece. By causing an electrochemical reaction at the contact portion, the contact portion of the workpiece with the processing tool is oxidized and dissolved in the aqueous solution, and the workpiece or process is added as the workpiece is dissolved. A method of processing a workpiece, wherein the workpiece is processed by moving a contact portion between the workpiece and a processing tool by moving a tool.   The method for processing a workpiece according to any one of claims 1 to 3, wherein the conductive material is a material having a catalytic action in an oxidation reaction of a material constituting the workpiece.   5. The method for processing a workpiece according to claim 4, wherein the conductive material is at least one metal selected from the group consisting of platinum, gold, iridium, and alloys thereof.   The said processing tool is formed in wire shape, blade shape, or needle shape, The processing method of the workpiece of any one of Claims 1-3 characterized by the above-mentioned.   The said processing tool has a linear processed surface, The said process is formation of the cut | notch to a workpiece, or cutting of a workpiece, The any one of Claims 1-3 characterized by the above-mentioned. The processing method of the workpiece described in 2.   A workpiece made of at least one material selected from the group consisting of silicon, silicon carbide, and a semiconductor containing a group III-V element is immersed in an aqueous solution containing hydrogen fluoride or fluoride ions, Then, at least the surface is made of a conductive material and is brought into contact with a processing tool formed separately from the workpiece, and an electrochemical reaction is performed at the contact portion with the workpiece using the processing tool as an anode. By causing the workpiece to oxidize the contact portion of the workpiece with the processing tool and dissolve it in the aqueous solution, the workpiece or the processing tool is moved along with the dissolution of the workpiece. After moving the contact portion between the workpiece and the processing tool to form a hole or groove in the workpiece, at least a part of the processing tool used to form the hole or groove is placed in the hole or groove. Remaining Wiring forming method comprising Rukoto.   A semiconductor wafer made of at least one material selected from the group consisting of silicon, silicon carbide, and a semiconductor containing a group III-V element is immersed in an aqueous solution containing hydrogen fluoride or fluoride ions. And at least the surface is made of a conductive material and is brought into contact with a processing tool formed separately from the semiconductor wafer, and an electrochemical reaction is caused at the contact portion with the semiconductor wafer using the processing tool as an anode. The portion of the semiconductor wafer that contacts the processing tool is oxidized and dissolved in the aqueous solution, and the semiconductor wafer or the processing tool is moved by moving the semiconductor wafer or the processing tool as the semiconductor wafer is dissolved. The contact portion is moved to form a hole or groove in the semiconductor wafer, and then used to form the hole or groove in the hole or groove. Method of manufacturing a semiconductor substrate and forming a wiring by remaining at least a part of the processing tool.   10. The method of manufacturing a semiconductor substrate according to claim 9, wherein the processing tool left in the hole or groove is used as a wiring as it is.   After removing the aqueous solution, the semiconductor material is supplied into the hole or groove with an electrolyte solution that does not dissolve the material constituting the semiconductor wafer and its oxide, and the processing tool left in the hole or groove is used as the anode. Forming an insulating film made of an oxide of a material constituting the semiconductor wafer at a contact portion with the wiring made of the processing tool in the semiconductor wafer by causing an electrochemical reaction at the contact portion with the wafer; 11. The method of manufacturing a semiconductor substrate according to claim 10, wherein   10. The method of manufacturing a semiconductor substrate according to claim 9, wherein the conductive material on the surface of the processing tool left in the hole or groove is used as a catalyst for forming a wiring by film growth.