JP2009200360A - Surface processing method for silicon member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface processing method for a silicon member in which metal components and dirt components sticking on a surface of the silicon member during machine processing for cutting a silicon ingot or silicon block by a band saw, wire saw or the like can be effectively removed. <P>SOLUTION: In the surface processing method for the silicon member, the silicon ingot or silicon block is fixed to a pedestal with an adhesive and then cut using a cutting device while abrasive slurry is supplied and the dirt components sticking on the surface of the cut silicon member are removed. The surface processing method of the silicon member includes (1) a step of processing using a surface water-repelling agent for the silicon member after processing using a processing liquid for metal component dissolution or processing using the processing liquid for metal component dissolution after processing using the surface water-repelling agent for the silicon member, and (2) a step of processing on the silicon member using a surface hydrophilizing agent for the silicon member. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface treatment method for a silicon member. More specifically, the present invention relates to a cutting device material metal adhering to these silicon members and an abrasive slurry used during the cutting process when a silicon ingot or silicon book is cut with a cutting device such as a band saw or a wire saw. The present invention relates to a method for treating the surface of a silicon member that can effectively remove contaminants generated by the above.

  Semiconductor silicon is used as a substrate material for semiconductor elements, semiconductor integrated circuits (ICs), solar cells, and the like. In particular, some solar cell substrate materials that convert sunlight into clean electrical energy are made of thin-film organic materials, but are often made of silicon semiconductor substrates because of their good photoelectric conversion efficiency. Has been.

A solar cell using a silicon semiconductor substrate is manufactured using a semiconductor wafer (hereinafter simply referred to as “wafer”) obtained by processing a polycrystalline or single crystal silicon semiconductor material. This wafer
(1) A step of cutting a silicon ingot having a predetermined size into a large silicon block having a predetermined size using a large band saw such as a diamond band saw,
(2) cutting the large silicon block with a similar small band saw to form a silicon block of a predetermined shape;
(3) A step of applying an adhesive to the silicon block and fixing it to the pedestal,
(4) A step of setting a base on which a silicon block is fixed to a cutting device made of a multi-wire saw, and slicing into a thin wafer while supplying abrasive slurry,
(5) A step of immersing the sliced wafer in a treatment solution in a treatment tank to separate the sliced wafer from the pedestal, and removing and cleaning the adhesive and contaminants attached to each wafer;
(6) a step of drying the cleaned wafer;
(7) Inspection process,
It is manufactured through each process.

  In these steps, when cutting with a cutting device such as a band saw or a wire saw, the band saw or the wire saw comes into contact with the silicon block, so that the metal constituting the cutting device adheres to the surface of the silicon block. In addition, when the silicon block is sliced with a band saw or a multi-wire saw to form a wafer, since the abrasive slurry is supplied, the abrasive slurry adheres to the surface of the obtained wafer. Further, even after the wafer is immersed in the treatment liquid in the treatment tank and cleaned, dirt may adhere to the wafer. Therefore, it becomes necessary to remove metal components and dirt components adhering to the wafer surface.

  For example, Patent Document 1 below discloses a wafer processing method in which acid treatment and alkali treatment are alternately performed in order to remove metal components and dirt components adhering to the wafer surface. Specifically, after slicing a single crystal ingot, it is immersed in an acid solution to remove the work-affected layer formed on the front and back surfaces of the wafer, and after mechanical polishing (lapping), alkali washing is performed to perform machining. After the contamination is removed, an acid etching process and an alkali etching process are further performed to remove the work-affected layers on the front and back surfaces of the wafer by machining introduced by the lapping process.

Further, Patent Document 2 below discloses a substrate processing method for removing metal impurities from a substrate after a surface portion is cut out from a silicon ingot made of silicon or silicon oxide. This processing method includes a step of removing a metal impurity on a surface portion of a substrate by supplying a treatment liquid composed of an alkaline solution containing CyDTA (trans-1,2-diaminocyclohexanetetraacetic acid) at a predetermined mass% or more, And a step of reacting CyDTA with the metal impurities removed from the dispersion and dispersed in the treatment liquid.
JP 2004-356252 A (paragraphs [0010], [0011], FIG. 1) JP 2005-310845 A (paragraphs [0010] to [0015])

  Both band saws and wire saws are made of steel. For example, a piano wire made of steel wire is used for the wire saw, and this piano wire is usually plated with brass on its surface. When a silicon block is cut using a wire saw made of such a material, the material of the wire saw comes into direct contact with the silicon block, so that the material such as iron, zinc, etc. , Metal such as copper adheres. In addition, dirt may adhere to the sliced wafer even in the slurry removal step.

  Of these deposits, those that can be seen with the naked eye are easily detected in the inspection process and can be removed, but detection of the metal component adsorbed on the silicon member is difficult. For this reason, when various electronic devices are formed using the silicon member to which the metal component is adsorbed, the performance and quality are adversely affected. For example, the adsorbed metal component becomes a lifetime killer when the silicon member is heat-treated, and the lifetime is shortened. When the lifetime is shortened, for example, the photovoltaic-electric exchange efficiency is lowered in a solar cell, and the current amplification factor is lowered in a transistor. Such metal components can be removed to some extent by the methods disclosed in Patent Documents 1 and 2, for example, but cannot be completely removed, and improvement is required to further improve quality. ing.

  Therefore, the present inventors examined the cause of the generation of the soil, and ascertained that the soil component is mainly composed of an adhesive residue and an abrasive residue mixed in the slurry. Of these soil components, the adhesive residue can be removed by reviewing the curing and peeling conditions of the adhesive used, but it has been found that the abrasive residue is difficult to remove. That is, the abrasive grains are usually carbon silicon-based abrasive grains. However, natural oxide films and silicates are used depending on chemicals such as acid and alkali used in abrasive slurry liquid, slurry removal, and wafer peeling operations. Since these natural oxide films and silicates are stably adsorbed on the surface of the silicon member, it is difficult to remove them.

  Therefore, the inventors have confirmed the removal method of this abrasive grain residue by various experiments, and can be removed by hydrophobizing the surface of the silicon member using hydrofluoric acid or an aqueous solution obtained by adding ammonium fluoride to hydrofluoric acid. In addition, the above metal components are not of common physical properties such as hydrochloric acid, aqueous ammonia, ammonium persulfate, and ferric chloride, but can be removed by using these chemicals, and these treatments can be combined. Thus, it has been found that the metal component and the dirt component can be more effectively removed, and the present invention has been completed.

  That is, the present invention was made to solve such problems of the prior art, and the object of the present invention is to provide silicon by machining such as cutting a silicon ingot or a silicon book with a band saw or a wire saw. An object of the present invention is to provide a surface treatment method for a silicon member that can effectively remove metal and dirt adhering to the surface of the member.

In order to achieve the above object, the surface treatment method for a silicon member according to the present invention fixes a silicon ingot or a silicon block to a pedestal with an adhesive, and then cuts using a cutting device while supplying an abrasive slurry. In the silicon member surface treatment method for removing a dirt component adhering to the surface of the cut silicon member, the following steps (1) and (2) are sequentially performed on the silicon member.
(1) A process of treating with a surface water-repelling agent for a silicon member after treatment with the metal component-dissolving treatment liquid, or a treatment with the treatment liquid for dissolving a metal component after treating with a surface water-repelling agent of the silicon member. ,
(2) A step of treating the silicon member with a surface hydrophilizing agent of the silicon member.

  The base material of the band saw is steel, and the base material of the wire saw is made of piano wire which is a steel component. Moreover, in order to make a wire saw easy to process a piano wire, the surface of the base material which consists of a piano wire is brass-plated which is copper and a zinc alloy. Therefore, after fixing the silicon ingot or the silicon block to the pedestal with an adhesive and then cutting while supplying the abrasive slurry using a cutting device such as a band saw or wire saw, the surface of the obtained silicon member is made of steel, copper. In addition to the adhesion of metal components such as zinc, dirt components resulting from the abrasive slurry adhere. These dirt components adhere to the surface or inside of the silicon member as elemental metal components, natural oxides or silicates.

  Further, since the silicon member is used for manufacturing various semiconductor elements, semiconductor integrated circuits, solar cells, etc., it is necessary to clean the surface of the silicon member. When the surface of the silicon member is cleaned, either a hydrophobic surface or a hydrophilic surface is obtained depending on the type of treatment liquid used for cleaning. The cleaned hydrophobic surface has a large part of the surface of the silicon member made of silicon element, and the cleaned hydrophilic surface has a part of the surface of the silicon member partially made of silicon element partially hydroxyl or oxygen. Atoms are combined to form a hydroxide or oxide. Silicon with a hydrophilic surface to improve wettability or reactivity with chemicals and chemicals used when processing silicon members to manufacture various semiconductor elements, semiconductor integrated circuits, solar cells, etc. Many members are used.

  If the surface of the silicon member is treated with a metal component dissolving treatment solution such as iron, copper and zinc, these metal components and salts of these metal components adhering to the surface of the silicon member are easily dissolved. However, the silicon member itself, silicon natural oxide and silicate are hardly dissolved. However, when the surface of the silicon member is treated with the surface water-repellent agent of the silicon member, the silicon member itself, the natural oxide or silicate of silicon is dissolved, and the surface made of clean silicon element is exposed. A commonly used surface water-repellent agent for silicon members is not necessarily useful for dissolving metal components such as iron, copper and zinc.

  Therefore, according to the surface treatment method for a silicon member of the present invention, various metal components and salts of these metal components adhering to the surface of the silicon member through the step (1) are dissolved. Since not only the natural oxide or silicate of silicon but also the surface of the base of the silicon member itself is dissolved, impurities such as metal elements do not exist, and a hydrophobic surface made of clean silicon element is exposed. Thereafter, through the step (2), a silicon member having a clean hydrophilic surface is obtained, and can be used for manufacturing various kinds of high-quality semiconductor elements, semiconductor integrated circuits, solar cells, and the like. .

  In the method for treating a surface of a silicon member according to the present invention, the metal component dissolving treatment liquid is preferably composed of a hydrochloric acid aqueous solution or a mixed aqueous solution of hydrochloric acid and hydrogen peroxide.

  Hydrochloric acid favorably dissolves metal elements such as iron, copper and zinc and salts of these metals. Further, the mixed aqueous solution of hydrochloric acid and hydrogen peroxide can easily dissolve trace metal elements in steel that are difficult to be oxidized by the oxidizing power of hydrogen peroxide. Therefore, according to the silicon member surface treatment method of this aspect, the metal component can be efficiently removed from the surface of the silicon member by a single operation.

  Moreover, in the surface treatment method for a silicon member of the present invention, the step of treating with the metal component dissolving treatment liquid includes the step of treating with a copper and zinc dissolving treatment solution and the step of treating with an iron component dissolving treatment solution. Can be included.

  According to the surface treatment method for a silicon member of this aspect, by properly using a treatment liquid excellent in the solubility of copper and zinc and a treatment liquid excellent in the solubility of the iron component, iron, copper and Zinc can be dissolved.

  Moreover, in the silicon member surface treatment method of the present invention, it is preferable that the treatment liquid having excellent solubility of copper and zinc is ammonium persulfate.

  Since ammonium persulfate is excellent in the solubility of copper and zinc, according to the surface treatment method for a silicon member of this aspect, copper and zinc can be efficiently dissolved. In addition, ammonium persulfate has almost no solubility in iron components.

  Moreover, in the surface treatment method for a silicon member according to the present invention, the iron component dissolving treatment liquid is preferably an aqueous solution of ferric chloride.

  The aqueous solution of ferric chloride is excellent in solubility of iron components because ferric ions are reduced to ferrous ions and iron is oxidized to ferrous ions. Therefore, according to the silicon member surface treatment method of this aspect, iron and components existing on the surface of the silicon member can be satisfactorily removed. In addition, in this aqueous solution of ferric chloride, hydrochloric acid may be added in order to prevent hydrolysis of ferric chloride (production of ferric hydroxide).

  In the silicon member surface treatment method of the present invention, the surface water-repellent agent for the silicon member is preferably hydrofluoric acid or an aqueous solution obtained by adding ammonium fluoride to hydrofluoric acid.

  Hydrofluoric acid or an aqueous solution obtained by adding ammonium fluoride to hydrofluoric acid is excellent in solubility of silicon, silicon oxide, silicon hydroxide, and silicate. Therefore, according to the surface treatment method of a silicon member of such an aspect, the silicon member itself, the natural oxide or silicate of silicon are dissolved, and the surface made of clean silicon element is exposed.

  Further, in the surface treatment method for a silicon member of the present invention, the surface hydrophilizing agent for the silicon member is an aqueous solution of sodium hydroxide, potassium hydroxide, sodium oxide to which hydrogen peroxide is added, or an aqueous solution of potassium hydroxide. It is preferable that

  An aqueous solution of sodium hydroxide or potassium hydroxide reacts with silicon element to add a hydroxyl group or generate an oxide. When hydrogen peroxide is added to an aqueous solution of sodium hydroxide or potassium hydroxide, the reaction rate of such hydroxyl group addition or oxide formation increases due to the oxidizing power of hydrogen peroxide. Therefore, according to the silicon member surface treatment method of this aspect, a silicon member having an efficient clean hydrophilic surface can be obtained and used for manufacturing various types of high-quality semiconductor elements, semiconductor integrated circuits, solar cells, and the like. become able to.

  Hereinafter, the best embodiment of the present invention will be described with reference to the drawings. However, the embodiment shown below exemplifies a surface treatment method for a silicon member for embodying the technical idea of the present invention, and is intended to specify the present invention as the surface treatment method for a silicon member. And other embodiments within the scope of the claims are equally applicable.

  First, with reference to FIGS. 1 and 2, an outline of a silicon wafer manufacturing process to which a surface treatment method according to an embodiment of the present invention is applied and a cutting apparatus used in this process will be described. FIG. 1 is a process diagram showing a manufacturing process of a silicon wafer, and FIG. 2 is a schematic diagram of a main part of a multi-wire saw apparatus used in the process of FIG.

  The silicon wafer is manufactured by the following process. First, using an ingot manufactured by an ingot manufacturer or the like, the ingot is divided into, for example, a plurality of prismatic blocks 1 having a predetermined size using a large band saw such as a diamond band saw (S1). Next, these blocks 1 are formed in a predetermined shape by cutting off the end portions using the same small band saw (S2). These band saws are made of super steel material.

  A pedestal 2 having a predetermined shape is prepared in advance (S3-1), and the block 1 is bonded and fixed to the pedestal 2 with an adhesive (S3-2, S3). As shown in FIG. 2B, the adhesive fixing is performed by fixing a glass plate (not shown) to the pedestal 2 and applying a predetermined adhesive 3, for example, an adhesive made of epoxy resin, to the block 1. Place and fix.

  The block 1 fixed to the base 2 is sliced into thin pieces having a predetermined thickness by using a cutting device (S4). This cutting device uses a multi-wire saw device shown in FIG. 2A. The multi-wire saw device 4 is provided with three rollers 6A to 6C around which one wire 5 is wound. Among these rollers, the roller 6A is connected to a drive source such as a motor (not shown) to be a drive roller, and the other two rollers 6B and 6C rotate following the rotation of the drive roller 6A. It is a driven roller. The driving roller 6A is rotated at a set speed by a driving source.

  Each of the rollers 6A to 6C has a plurality of grooves 7a to 7c formed at a predetermined pitch on the outer peripheral surface thereof, and is wound so that one wire 5 is fitted into the grooves 7a to 7c. The pitch of the grooves 7a to 7c is set to the thickness of a thin plate cut out by cutting. The wire 5 is a hard steel wire or a piano wire. The surface of the piano wire is plated with brass, which is copper and a zinc alloy, so that the piano wire can be easily processed. One end 5A of the wire 5 is wound around a delivery reel (not shown), and the other end 5B is wound around a take-up reel (not shown). The wire 5 is guided while receiving tension of several kilograms according to the rotation of the driving roller 6A, and is wound from the feed reel to the take-up reel while traveling along a certain direction at a predetermined speed.

In order to cut the block 1 using the multi-wire saw device 4, a predetermined speed V is applied to a portion stretched between the driven rollers 6 </ b> B and 6 </ b> C in the wire 5 traveling on the base 2 to which the block 1 is fixed. _The block 1 is moved to ₀ and pressed against the wire 5 to be cut. When the block 1 is cut, the adhesive 3 is cut and reaches the glass plate fixed to the pedestal 2, and the glass plate is cut to a part where it is cut. At the time of cutting using the multi-wire saw device 4, the abrasive slurry is supplied to the rollers 6A to 6C and the block 1 (S4-1). This abrasive slurry is a cutting fluid in which silicon carbide abrasive grains (carbon random) are mixed with oil or water. By cutting the block 1, a large number of wafers having a predetermined thickness determined by the pitch of the grooves 7a to 7c and the thickness of the wire 5 are simultaneously cut out.

  In the process so far, the cut block 1 and the sliced wafer, that is, the silicon member, have components such as abrasive slurry, adhesive, and metal attached to the surface. That is, in the steps S1 and S2, the block cut with the band saw is rubbed with the band saw, and at this time, the material of the band saw, that is, iron adheres to the silicon crystal. Similarly, also in step S4, copper, zinc, and iron are attached as an elemental metal to a silicon member on a wafer cut with a brass-plated piano wire. Further, in this step S4, since the slicing is performed while supplying the abrasive slurry, the abrasive slurry and the adhesive adhere to the sliced wafer.

  Among the adhered abrasive slurry, adhesive and metal component, the abrasive slurry removes the dispersion medium such as abrasive grains and coolant by a known method such as degreasing and water washing (S5). Further, since the adhesive is peeled off by using an epoxy resin adhesive, the resin is peeled off by immersing the resin in a strong alkaline solution or a strong acid solution to reduce the adhesive force (S6). .

  However, even after these slurry removal and adhesive peeling steps (S5, S6) are completed, the metal component attached to the wafer is not completely removed. In these steps, a new dirt component may be attached to the wafer. This dirt component is mainly the residue of the adhesive 3 and the abrasive grain residue. Therefore, among these residues, the adhesive residue can be removed in steps S5 and S6 by reviewing the curing conditions and peeling conditions of the adhesive used. However, the abrasive grain residue is difficult to remove because it is adsorbed to the silicon member in a stable form as a natural oxide film or silicate generated during treatment with various aqueous solutions. These natural oxide films and silicates are produced when silicon members and carbon silicon-based abrasives come into contact with chemicals such as acid and alkali used in abrasive slurry liquid and abrasive slurry removal and wafer peeling operations. Is.

  Therefore, in the next step S7, the surface treatment of the wafer is performed to remove metal components and dirt components. This surface treatment employs a combination of the following (a) metal component removal treatment, (b) water-repellent treatment, and (c) hydrophilic treatment. Note that either of the following treatments (a) and (b) may be performed first, but both must be performed, and the hydrophilic treatment (c) must be performed last.

(A) Metal component removal treatment Among the metal components adhering to the wafer, iron dissolves in an acid solution containing hydrochloric acid and ferric chloride, and therefore these aqueous solutions are removed as a metal component dissolution treatment solution. Further, brass is an alloy of copper and zinc and dissolves in ammonium persulfate, so this aqueous solution is removed as a metal component dissolving treatment liquid. Further, ammonia water or hydrogen peroxide water can be added to the ammonium persulfate aqueous solution as a reaction accelerator. When ammonia water is added to the ammonium persulfate aqueous solution, the pH of the ammonium persulfate aqueous solution can be stabilized, so that the dissolution rate of copper and zinc can be improved. Moreover, when hydrogen peroxide is added to the ammonium persulfate aqueous solution, the hydrogen peroxide has oxidizing properties, so that the dissolution rate of copper and zinc can be improved.

  Hydrochloric acid, aqueous ammonia, ammonium persulfate, and ferric chloride have no common physical properties, but these chemicals can dissolve iron, copper, zinc, and the like. Moreover, since zinc is an amphoteric metal, it dissolves in both alkali and acid, but there is a difference in solubility. For iron, copper and zinc, an aqueous hydrochloric acid solution containing hydrochloric acid or hydrogen peroxide is effective. Further, when the iron content is high, ferric chloride (hydrochloric acid acid) is preferable. Further, when the contents of copper and zinc are high, ammonium persulfate (ammonia) is preferable.

(B) Water-repellent treatment Dirt components are silicon dioxide, silicon hydroxide, silicate formed on the surface of the silicon member during the cutting process of the silicon member, the abrasive slurry removing process, the adhesive peeling process, etc. Etc., and can be eliminated by removing these silicon dioxide, silicon hydroxide, silicate and the like. Therefore, the silicon member is immersed in an aqueous solution containing hydrofluoric acid as a surface hydrophilizing agent for the silicon member to remove silicon compounds such as silicon dioxide, silicon hydroxide, and silicate. When the silicon member is immersed in an aqueous solution containing hydrofluoric acid, the surface of the silicon member base itself is dissolved and the silicon element is exposed, so that the surface of the obtained silicon member becomes hydrophobic. By this hydrophobic treatment process, the dirt component adsorbed on the surface of the silicon member is removed.

(C) Hydrophilization treatment After completion of the treatments (a) and (b) above, the wafer is made hydrophilic by the addition of sodium hydroxide, an aqueous solution of potassium hydroxide or hydrogen peroxide as a treatment agent. By immersing in an aqueous solution of sodium and potassium hydroxide, the surface of the silicon member is hydrophilized and cleaned. An aqueous solution of sodium hydroxide or potassium hydroxide reacts with silicon element to add a hydroxyl group or generate an oxide. When hydrogen peroxide is added to an aqueous solution of sodium hydroxide or potassium hydroxide, the reaction rate of such hydroxyl group addition or oxide formation increases due to the oxidizing power of hydrogen peroxide. This hydrophilic treatment is intended to increase wettability or reactivity with chemicals and chemicals used when manufacturing various semiconductor elements, semiconductor integrated circuits, solar cells, etc. by processing silicon members. is there.

  Next, a processing pattern in which the order of the processes (A) to (C) is changed will be described with reference to FIG. FIG. 3 is a pattern flow diagram showing three processing patterns.

[First processing pattern 7A]
As shown in FIG. 3A, the first processing pattern 7A is
(A) removing the metal adhering to the surface of the silicon member with the first treatment liquid (S7-1),
(B) Next, the surface of the silicon member is subjected to hydrophobic treatment with the second treatment liquid to remove the surface dirt (S7-2),
(C) Thereafter, the surface of the silicon member is hydrophilized and washed with a third treatment liquid (S7-3).

  As the metal component dissolving treatment solution, hydrochloric acid or an aqueous solution containing hydrogen peroxide in hydrochloric acid is used. By using this metal component dissolving treatment solution, iron, copper and zinc can be removed simultaneously. As the surface water-repelling agent for the silicon member, hydrofluoric acid or an aqueous solution obtained by adding ammonium fluoride to hydrofluoric acid is used. When this surface hydrophobicizing agent for silicon members is used, silicon dioxide, silicon hydroxide, silica formed on the surface of the silicon member during the cutting process of the silicon member, the abrasive slurry removing process, the adhesive peeling process, etc. Since the acid salt and the like can be dissolved and removed, and the surface of the base of the silicon member itself is dissolved, impurities such as metal elements do not exist, and a hydrophobic surface made of clean silicon element is exposed. Furthermore, as the surface hydrophilizing agent for the silicon member, an aqueous solution of sodium hydroxide or potassium hydroxide or an aqueous solution of sodium oxide or potassium hydroxide to which hydrogen peroxide is added is used. By using the surface hydrophilizing agent for the silicon member, a silicon member having a clean hydrophilic surface can be obtained.

[Second processing pattern 7B]
As shown in FIG. 3B, the second processing pattern 7B is obtained by reversing the steps (a) and (b) of the first processing pattern, and after executing the step (b) first, B) Execute the process. There are cases where the metal component is in elemental form and attached to the silicon member, and may be contained in the silicon oxide as a salt. According to the second processing pattern 7B, the silicon oxide film is first dissolved and removed, and then the metal component adhering to the surface of the silicon member is dissolved and removed. Components can be removed.

[Third processing pattern 7C]
As shown in FIG. 3C, the third treatment pattern 7C is the same as the step (a) of the first treatment pattern 7A in that copper and zinc are used for dissolving copper and zinc among the metal components attached to the surface of the silicon member. The step of removing with the treatment liquid and the step of removing iron with the iron component dissolving treatment liquid are then executed separately (S7-1 ′). An aqueous solution of ammonium persulfate is used for the treatment for dissolving copper and zinc. Further, a ferric chloride aqueous solution is used as the iron component dissolving treatment liquid.

  By appropriately selecting and executing these processing patterns, it is possible to remove and reduce the metal component and dirt component adhering to the silicon member. As a result, the yield of wafer manufacturing can be improved, and when this wafer is used for manufacturing devices such as various semiconductor elements, semiconductor integrated circuits, solar cells, etc., a device with high quality and improved performance can be obtained. Become.

  Hereinafter, an embodiment of the present invention using these processing patterns will be described.

  The surface treatment method for a silicon member according to Example 1 is a method using the first treatment pattern 7A. That is, this is a surface treatment method for a silicon member in which treatment with a surface hydrophobizing agent for the silicon member is performed after the treatment with the metal component dissolving treatment liquid, and finally the surface hydrophilizing agent treatment is performed on the silicon member. First, after slicing with a wire saw, the abrasive slurry liquid was removed, and the wafer separated from the adhesive 3 was immersed in an aqueous solution (room temperature) of hydrochloric acid, hydrogen peroxide solution, and water (1: 1: 4) for 3 minutes. Thereafter, the silicon oxide film was removed by dipping in a 10% hydrofluoric acid aqueous solution (room temperature, 1 minute) to make the silicon surface hydrophobic. Thereafter, the silicon surface was hydrophilized by immersion in an aqueous solution of sodium hydroxide at 60 ° C. and 20% by mass (temperature 60 ° C.) for 20 minutes. The obtained wafer is shown in Table 1 below together with the conventional method using the contamination defect rate in the inspection process and the adhesion amount of the metal component adhering to the silicon surface (atomic absorption analysis). The conventional method follows the method disclosed in Patent Document 1.

Moreover, the inductively coupled plasma emission analysis method (ICP apparatus; ICPS-8100 made by Shimadzu Corporation) was adopted as the analysis method of the metal component. A measurement sample was obtained by crushing one wafer (area is about 490 cm ² ), dissolving in 100 ml aqua regia (concentrated nitric acid: concentrated hydrochloric acid = 3: 1) maintained at 80 ° C. for 10 minutes, and collecting the filtrate. . This filtrate was introduced into an inductively coupled plasma optical emission spectrometer, the intensity of the wavelength peculiar to the metal was measured, quantified based on a calibration curve prepared with a standard sample, and converted into an adhesion amount per unit area. In addition, the stain defect rate is determined by visually observing surface stains, adhesion of foreign matter, and the remaining adhesive by visually observing them, and determining that all existing items are defective. The defect rate (%) is calculated as the number of defects / number of treatments × 100. did.

  The surface treatment method for a silicon member according to Example 2 is a method using the second treatment pattern 7B. That is, this is a silicon member surface treatment method in which a silicon member is first treated with a surface hydrophobizing agent, then treated with a metal component dissolving treatment solution, and finally a silicon member surface hydrophilizing agent treatment. First, after slicing with a wire saw, the abrasive slurry is removed, and the wafer peeled off from the adhesive 3 is immersed in an aqueous solution (room temperature) of hydrofluoric acid, ammonium fluoride, and water (1: 1: 10) for 1 minute to obtain silicon. The oxide film was removed to make the silicon surface hydrophobic. Thereafter, the silicon surface was hydrophilized by dipping in an aqueous potassium hydroxide solution (30 wt%) heated to 70 ° C. for 20 minutes. For the obtained wafer, the contamination defect rate in the inspection process and the adhesion amount of the metal component adhering to the silicon surface (atomic absorption analysis) were measured in the same manner as in Example 1, and the results are summarized in Table 1 below. Indicated.

  The surface treatment method for a silicon member according to Example 3 is a method based on the third treatment pattern 7C. That is, after first performing the process of treating with the metal component dissolving treatment liquid in two stages, the silicon member is treated with the surface hydrophobizing agent of the silicon member, and finally the surface hydrophilizing agent treatment of the silicon member is performed. This is a surface treatment method. After slicing with a wire saw, the slurry liquid was removed, and the silicon wafer peeled off from the adhesive 3 was immersed in an alkaline ammonium persulfate aqueous solution (20 wt%, 30 ° C.) for 3 minutes, and then an aqueous ferric chloride solution (30 wt%, It was immersed in room temperature for 5 minutes to dissolve and remove the metal. Thereafter, the silicon oxide film was dissolved and removed by immersion in an aqueous solution (room temperature) of hydrofluoric acid, ammonium fluoride, and water (1: 1: 10) for 1 minute to make the surface hydrophobic, and then heated to 60 ° C. The wafer obtained by dipping in an aqueous sodium hydroxide solution for 20 minutes to make the surface hydrophilic was used to determine the contamination defect rate in the inspection process and the amount of metal component adhering to the silicon surface (atomic absorption analysis). The measurement was performed in the same manner as in the case, and the results are summarized in Table 1 below.

  From the results shown in Table 1, according to the surface treatment method for a silicon member of the present invention, the metal adhered to the surface of the silicon member by machining such as cutting a silicon ingot or a silicon book with a band saw or a wire saw, and the like. It turns out that dirt can be removed effectively. Therefore, by using a wafer manufactured by applying the present invention, it is possible to improve the performance and quality of various electronic devices such as various semiconductor elements, semiconductor integrated circuits, and solar cells.

It is process drawing which shows the manufacturing process of a silicon wafer. It is a schematic diagram of the principal part of the multi-wire saw apparatus used at the process of FIG. It is process drawing which performs removal of a metal of this invention, removal of an oxide film, and dirt removal in order.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Silicon block 2 Base 3 Adhesive 4 Wire saw apparatus 5 Piano wire 6A-6C Roller

Claims (7)

After fixing the silicon ingot or silicon block to the pedestal with an adhesive, the surface of the silicon member is removed using a cutting device while supplying the abrasive slurry, and the dirt component adhering to the surface of the cut silicon member is removed. In the processing method, the silicon member surface treatment method is characterized by sequentially performing the following steps (1) and (2) on the silicon member.
(1) A process of treating with a surface water-repelling agent for a silicon member after treatment with the metal component-dissolving treatment liquid, or a treatment with the treatment liquid for dissolving a metal component after treating with a surface water-repelling agent of the silicon member. ,
(2) A step of treating the silicon member with a surface hydrophilizing agent of the silicon member.   2. The surface treatment method for a silicon member according to claim 1, wherein the metal component dissolving treatment liquid comprises a hydrochloric acid aqueous solution or a mixed aqueous solution of hydrochloric acid and hydrogen peroxide.   2. The silicon member according to claim 1, wherein the step of treating with the metal component dissolving treatment liquid includes a step of treating with a copper and zinc dissolving treatment solution and a step of treating with an iron component dissolving treatment solution. Surface treatment method.   4. The surface treatment method for a silicon member according to claim 3, wherein the treatment liquid having excellent solubility for copper and zinc is ammonium persulfate.   4. The surface treatment method for a silicon member according to claim 3, wherein the iron component dissolving treatment liquid is an aqueous solution of ferric chloride.   2. The surface treatment method for a silicon member according to claim 1, wherein the surface water-repelling agent for the silicon member is hydrofluoric acid or an aqueous solution obtained by adding ammonium fluoride to hydrofluoric acid.   2. The silicon according to claim 1, wherein the surface hydrophilizing agent of the silicon member comprises an aqueous solution of sodium hydroxide or potassium hydroxide, or an aqueous solution of sodium oxide or potassium hydroxide to which hydrogen peroxide is added. A surface treatment method for a member.

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