WO2014155624A1

WO2014155624A1 - Semiconductor-wafer manufacturing method and semiconductor wafer

Info

Publication number: WO2014155624A1
Application number: PCT/JP2013/059364
Authority: WO
Inventors: 山根　昭彦
Original assignee: Ｐｖクリスタロックスソーラー株式会社
Priority date: 2013-03-28
Filing date: 2013-03-28
Publication date: 2014-10-02

Abstract

Provided are: a manufacturing method in which a semiconductor wafer is cut using a fixed-abrasive technique and a texture can be formed across the entire surface of said semiconductor wafer, even with the use of an etching process using an acid; and a semiconductor wafer obtained via said manufacturing method. Said semiconductor wafer is manufactured via a fixed-abrasive slicing step, a wet-blast damage-layer formation step, and a drying step and is subjected to an etching process using an acid. In the slicing step, a crystalline ingot is cut by a core wire that has abrasive grains affixed to the surface thereof in a dispersed manner. In the damage-layer formation step, after the slicing step, the surface of the semiconductor wafer is sprayed with a slurry consisting of a liquid and abrasive grains. In the drying step, following the damage-layer formation step, the semiconductor wafer is dried.

Description

Semiconductor wafer manufacturing method and semiconductor wafer

The present invention relates to a method of manufacturing a semiconductor wafer that is etched with an acid for texture formation, and the semiconductor wafer.

Semiconductor wafers for solar cells are shipped through a slicing process for cutting a semiconductor wafer from a polycrystalline silicon ingot, a peeling process for peeling the semiconductor wafer from the support plate, and a final cleaning process for removing dirt and dust from the semiconductor wafer. Etched by battery manufacturer.

In the slicing step, lapping using a wire saw by a loose abrasive method or cutting using a wire saw by a fixed abrasive method can be employed. The free abrasive grain method is a method of cutting a semiconductor wafer by rubbing a slurry, which is a mixture of liquid and abrasive grains, onto a polycrystalline silicon ingot using a wire saw. In the slicing process by the free abrasive grain method, the semiconductor wafer is cut out while the abrasive grains contained in the slurry break the polycrystalline silicon ingot.

On the other hand, the fixed abrasive method is a method of cutting a semiconductor wafer by pressing a wire saw formed by dispersing and fixing abrasive grains on a core wire against a polycrystalline silicon ingot. The slicing process by the fixed abrasive method is to cut a semiconductor wafer while chopping a polycrystalline silicon ingot. Therefore, in the fixed abrasive method, there are few layers that become chips compared to the free abrasive method, and many semiconductor wafers can be cut out from one polycrystalline silicon ingot, and cracks and the like are generated. There is an advantage that the semiconductor wafer can be cut out thinly.

Etching is a process of forming uneven texture on the surface of the semiconductor wafer. If the surface of the semiconductor wafer is flat, part of the incident light is reflected and cannot be converted into current. For this reason, solar cell manufacturers have provided irregularities called textures on the surface, giving them the opportunity to re-enter part of the reflected light on the semiconductor wafer multiple times, reducing the surface reflectance, and thus the performance of the solar cell. Has improved.

Various methods can be adopted as the etching treatment, and examples thereof include an alkali etching treatment and an acid etching treatment. A typical example of the etching process using alkali is to add isopropyl alcohol into an alkaline solution of KOH or NAOH and immerse one or both sides of a semiconductor wafer in the alkaline solution for several minutes. A typical example of the etching process using an acid is one in which one or both sides of a semiconductor wafer are immersed in an acid solution containing hydrofluoric acid or nitric acid as a main component for about 1 to 2 minutes.

Japanese Patent Laying-Open No. 2005-311060

In the slicing process, as described above, the fixed abrasive method is more advantageous than the free abrasive method in terms of production cost, and the practical use of the fixed abrasive method is expected. However, when an acid etching process is performed, a uniform texture cannot be formed on a semiconductor wafer sliced by a fixed abrasive method.

That is, when a semiconductor wafer is cut out by the free abrasive grain method and etched with acid, a fine texture is formed on the entire surface of the semiconductor wafer.

However, when a semiconductor wafer is cut out by the fixed abrasive method and etched with acid, a partially flat region remains. As described above, the texture plays an important role in reducing the reflectance of sunlight and improving the performance of the solar cell, and the flat region on the semiconductor wafer cannot be overlooked.

Therefore, when manufacturing a semiconductor wafer on the premise of an etching treatment with an acid, a free abrasive grain method has to be adopted.

The present invention has been proposed in order to solve the above-described problems of the prior art, and while the semiconductor wafer is cut out by a fixed abrasive method, the entire surface of the semiconductor wafer is textured even in an etching process using an acid. It is an object of the present invention to provide a manufacturing method capable of forming a semiconductor wafer and a semiconductor wafer by the manufacturing method.

As a result of diligent research, the present inventors have thought that the texture formed by the etching treatment with acid is greatly influenced by the damaged layer existing on the semiconductor wafer before the etching treatment. Etching with acid is considered to be a method for removing only the damaged layer, and the shape of the damaged layer formed in as-slice (no processing after slicing) is similar to that of the texture. Because it is. The damaged layer is a concavo-convex layer formed on the surface of the semiconductor wafer and is generated in the slicing process.

In the loose abrasive method, since the semiconductor wafer is cut out so as to break the crystalline ingot, the entire surface of the semiconductor wafer is formed with unevenness in advance before the etching process. However, in the fixed abrasive method, the surface of the semiconductor wafer becomes a smooth surface cut with a knife, so that the uneven layer is incompletely formed.

Therefore, a first aspect according to the present invention is a method for manufacturing a semiconductor wafer before being etched with an acid for forming a texture, and includes the following steps.

(1) Slicing step of fixed abrasive method that cuts out the semiconductor wafer by cutting a crystalline ingot with a core wire in which abrasive particles are dispersed and fixed on the surface. (2) After the slicing step of the fixed abrasive method, the semiconductor A wet blast type damage layer forming step for forming a damaged layer on the semiconductor wafer by spraying a slurry of liquid and abrasive grains onto at least one surface of the wafer. (3) Next to the damaged layer forming process, washing with water A drying step of drying the semiconductor wafer through cleaning.

A finish cleaning process using a solvent for the semiconductor wafer may be omitted between the damaged layer forming process and the drying process. This is because the cleaning effect by the wet blasting process appears by combining the slicing process by the fixed abrasive method and the damaged layer forming process by the wet blasting process.

In the combination of the slicing process by the fixed abrasive method and the damaged layer forming process by the wet blasting process, it is understood that the texture unevenness density and the damage layer depth can be controlled by the grain size of the abrasive grains used in the wet blasting process. It was. That is, in this damage layer forming step, the particle size of the abrasive grains contained in the slurry can be changed according to the target uneven density of the texture. In the damage layer forming step, the grain size of the abrasive grains contained in the slurry can be changed according to the depth of the damage layer to be formed.

A second aspect according to the present invention is a semiconductor wafer before being etched with an acid to form irregularities on the surface, which is a fixed abrasive that cuts a crystalline ingot with a core wire having abrasive grains fixed on the surface. It is characterized in that a damage layer is formed on the surface by being cut out by a grain method, and after being cut out, a slurry of liquid and abrasive grains is sprayed on at least one surface by a wet blast method.

According to the present invention, a damaged layer can be formed on the entire surface even when a semiconductor wafer is cut out by a fixed abrasive method, and a texture can be formed even if an etching process with an acid is performed. Therefore, many semiconductor wafers can be cut out from one crystalline ingot as compared with the free abrasive grain method, and the manufacturing cost of the semiconductor wafer for solar cells can be reduced.

It is a flowchart which shows the manufacturing process of the semiconductor wafer which concerns on this embodiment. It is a schematic diagram which shows the slicing process of a fixed abrasive system. It is a schematic diagram which shows a peeling process. It is a schematic diagram which shows a wet blast process. It is a table | surface which shows the conditions of a wet blast process. 2 is a photograph showing observation results after wet blasting treatment under conditions 1 and 2 of Example 1. FIG. It is a photograph which shows the observation result of the case where wet blasting is performed under Condition 1 and Comparative Example 1. It is a photograph which shows the observation result of the case where wet blasting is performed under Condition 2 and Comparative Example 1. It is a figure which shows the observation result of Example 2, the comparative example 2, and the comparative example 3. FIG.

Embodiments of a semiconductor wafer manufacturing method according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a flowchart showing a semiconductor wafer manufacturing process.

The semiconductor wafer is for solar cells, and is manufactured by cutting out a crystalline ingot. The crystalline ingot is, for example, a polycrystalline silicon ingot. The manufacturing process is as follows. That is, as shown in FIG. 1, a semiconductor wafer is sliced from a crystalline ingot (step S01), a peeling step (step S02) for peeling the cut semiconductor wafer, and a damage layer on the surface of the semiconductor wafer. The damaged layer forming step (step S03) for forming the semiconductor wafer and the drying step (step S04) for drying the semiconductor wafer through washing with water are sequentially manufactured.

The semiconductor wafer that has undergone this process is shipped to a solar cell manufacturer through an inspection process that separates good and defective products. In the solar cell manufacturer, an uneven texture is formed on the surface, and further processing for the solar cell is performed. The formation of the texture is intended to reduce the surface reflectance. The formation of the texture is generally performed by various etching processes. However, in the present manufacturing method of a semiconductor wafer, it is assumed that the etching process with an acid is performed.

(Slicing process)
In the slicing step, a plurality of semiconductor wafers are cut out from the crystalline ingot by a fixed abrasive method. In the fixed abrasive method, the crystalline ingot is cut with a wire saw made of a core wire in which abrasive particles are dispersed and fixed on the surface.

FIG. 2 is a schematic diagram showing a fixed abrasive grain slicing process. In FIG. 2, the code | symbol 100 has shown the crystalline ingot. As shown in FIG. 2, a plurality of wire saws 10 are arranged in parallel and can travel between the

rotating rollers

11 a and 11 b. On the other hand, one side of the crystalline ingot is bonded to the support plate 12. A plurality of semiconductor wafers are cut out from the crystalline ingot by moving relative to the traveling wire saw 10 while pressing the crystalline ingot supported by the support plate 12. The crystalline ingot is sliced until the support plate 12 is reached.

The core wire of the wire saw 10 is desirably a high carbon steel including a metal wire such as iron, nickel, cobalt, chromium, tungsten, molybdenum, copper, titanium, aluminum, and an alloy selected from these, or a piano wire. Various kinds of abrasive grains can be applied as long as the abrasive grains dispersed and fixed to the core wire can cut silicon. For example, it is desirable to use diamond, CBN, SiC, or a mixture thereof as abrasive grains. The abrasive grains are dispersed and fixed to the core wire using various methods such as a resin bond method, an electrodeposition method, or a brazing method.

As the support plate 12 bonded to the crystalline ingot, a glass plate can be mentioned. The adhesive that bonds the crystalline ingot and the support plate 12 is not particularly limited, but it is desirable that the adhesive be bonded with an epoxy adhesive.

(Peeling process)
In the peeling step, the plurality of semiconductor wafers cut out from the crystalline ingot are peeled off from the support plate 12. FIG. 3 is a schematic diagram showing a peeling process. In FIG. 3, reference numeral 200 indicates a semiconductor wafer. As shown in FIG. 3, the support plate 12 and the semiconductor wafer are immersed in a basket 13 filled with a stripping solution 14 for dissolving the adhesive. As the stripping solution 14, an aqueous solution in which lactic acid is diluted with water can be used.

(Damage layer forming process)
In the damaged layer forming step, a uniform damaged layer is formed on the entire surface of the semiconductor wafer sliced by the fixed abrasive method after the fixed abrasive method slicing step and before the texture formation by etching using acid. Further, a rough cleaning step may be included between the slicing step and the damaged layer forming step.

The damage layer is a layer formed by irregularities on the surface of the semiconductor wafer. Forming a uniform damaged layer on the entire surface of the semiconductor wafer means that a damaged layer is formed on one or both sides of the semiconductor wafer, there is no smooth area on the surface, and the unevenness is formed evenly as a whole. is there.

In this damaged layer forming step, the surface of the semiconductor wafer is wet blasted. The wet blasting process is a process of grinding the surface of the semiconductor wafer by spraying a slurry of liquid and abrasive grains onto the surface of the semiconductor wafer.

FIG. 4 is a schematic diagram showing the wet blasting process. As shown in FIG. 4, in the wet blasting process, a slurry in which a liquid and abrasive grains are mixed is sprayed from a nozzle 15 with compressed air. The width of the nozzle 15 is sufficiently wider than the width of the semiconductor wafer, and the slurry ejected from the nozzle 15 is directed to the surface of the semiconductor wafer. The nozzle 15 and the semiconductor wafer can be moved relatively, and the entire surface of the semiconductor wafer is wet-blasted. In this wet blasting process, scanning on the semiconductor wafer by the nozzle 15 may be repeated once or a plurality of times.

It is desirable that the abrasive used in the wet blasting process is any one of alumina, diamond, CBN, SiC, or a mixture thereof. Moreover, as a liquid mixed with abrasive grains, water is mainly used, but a surfactant may be contained. The mixing ratio of abrasive grains in the slurry is preferably 10 to 30 vol%. In this range, in addition to the damage layer forming effect, the cleaning effect of the semiconductor wafer appears and the finishing cleaning process is not necessary.

The grain size of the abrasive grains can be changed according to the depth of the target damage layer and the target uneven density of the texture formed by etching. In other words, when a semiconductor wafer is sliced by the fixed abrasive method, if the particle size of the abrasive used in this wet blasting process is large, the damage layer becomes deep, in other words, the height difference of the unevenness tends to increase. It was. In addition, when a semiconductor wafer is sliced by the fixed abrasive method, if the particle size of the abrasive used in the wet blasting process is large, the uneven density of the texture tends to be improved. There is a tendency for the area of the two irregularities to become smaller and closer.

In addition, when slicing a semiconductor wafer by the free abrasive grain method, if the grain size of the abrasive grain used in slicing is large, the convex part formed at the time of slicing will be shaved, and the surface roughness will be smooth. Therefore, it was difficult to control the depth of the damaged layer.

(Drying process)
In the drying process, the semiconductor wafer is placed in a drying chamber to remove moisture. This drying step is performed after washing with water following the damaged layer forming step. Washing with water is a process of washing away dirt and dust. That is, when wet blasting is performed, a finish cleaning step using ultrasonic waves in a solvent such as an alkali can be omitted.

(Etching process)
In the etching process, the surface of the semiconductor wafer is exposed to an etching solution. Specifically, while rotating the semiconductor wafer, an etching solution is dropped on the surface, and the etching solution is spread over the entire surface of the semiconductor wafer. A semiconductor wafer may be immersed in an etching solution. The etching process is not limited to this, and various methods can be adopted. The etchant is an acid and is preferably a hydrofluoric acid solution that is a mixed acid of hydrofluoric acid and nitric acid. For example, phosphoric acid, acetic acid, carboxylic acid, or a surfactant may be added.

(Confirmation of damage layer formation effect)
In order to confirm the effect of forming the damaged layer of the semiconductor wafer that has undergone the fixed abrasive grain slicing process and the damaged layer forming process of the wet blasting process, the semiconductor wafer is manufactured as follows and subjected to an etching process with an acid and observed. Went. The present invention is not limited to these examples.

(Example 1)
A polycrystalline silicon wafer with a wafer thickness of 180 μm is cut out from the polycrystalline silicon ingot by a fixed abrasive method, and after peeling, the polycrystalline silicon wafer is wet-blasted only on one side under the conditions shown in FIG. did.

That is, under condition 1 of the wet blast treatment, alumina A # 2000 (Mako Co., Ltd., Macorundum, particle size: 6.7 μm) is mixed with water to produce a slurry having an abrasive concentration of 20 vol%. This slurry was sprayed onto the polycrystalline silicon wafer at a compressed air pressure of 0.2 MPa using a wet blasting device (manufactured by Macau Corporation, Sigma, nozzle width: 600 mm). The projection distance between the nozzle tip from which the slurry is ejected and the polycrystalline silicon wafer was 20 mm, and the projection angle of the polycrystalline silicon wafer with respect to the slurry injection axis was 90 °. The polycrystalline silicon wafer and the nozzle were moved relative to each other at 30 mm / sec, and the slurry was projected onto the entire surface of the polycrystalline silicon wafer. The number of scans of the nozzle is one.

Condition 2 of the wet blasting process is a wet blasting apparatus in which alumina A # 800 (manufactured by Macau Corporation, Macorundum, particle size: 14.0 μm) and water are mixed to produce a slurry having an abrasive concentration of 20 vol%. (Mako Co., Ltd., Zeta, Nozzle width: 320 mm)

Then, after washing with water and drying treatment, as an etching treatment with acid, a hydrofluoric acid solution was spread evenly over the wet-blasted surface of each polycrystalline silicon wafer.

In order to confirm the effect of the wet blast treatment, the surface state of the polycrystalline silicon wafer was observed with a laser microscope (Keyence Corporation, VL-9700) before and after the wet blast treatment and after the etching treatment with acid.

(Comparative Example 1)
A polycrystalline silicon wafer having a wafer thickness of 180 μm is cut out from the polycrystalline silicon ingot by a fixed abrasive grain method, and after performing a peeling process, an etching process using acid under the same conditions as in Example 1 without performing a wet blasting process. Went.

(result)
The observation results before the wet blast treatment of Example 1 and the observation results after the wet blast treatment according to Conditions 1 and 2 of Example 1 are shown in FIG.

As shown in FIG. 6, before the wet blasting process, there are smooth flat regions R in some places along the traveling direction of the wire saw, whereas after the wet blasting process, in both conditions 1 and 2, It can be confirmed that the smooth flat region R disappears and a damaged layer is formed as a whole.

As a result of condition 1 wet blasting using abrasive grains having a particle size of 6.7 μm, the depth of the damaged layer was about Ra: 0.387 μm and Rz: about 5.120 μm. Further, as a result of wet blasting treatment under condition 2 using abrasive grains having a particle size of 14.0 μm, the depth of the damaged layer was about Ra: 0.459 μm and Rz: 5.934 μm. Note that the depth of the damaged layer is determined by masking a part of the polycrystalline silicon wafer so that the wet blast process does not reach the area, and measuring the step between the wet blast process and the masked area. It was obtained by doing.

7 and 8 show the observation results after etching with acid for Example 1 and Comparative Example 1. FIG. 7 shows the observation results of the case of wet blasting under condition 1 (wet blasting abrasive grain size 6.7 μm) and Comparative Example 1. FIG. 8 shows the condition 2 (wet blasting abrasive grain of It is an observation result of the case of wet blasting with a diameter of 14.0 μm) and Comparative Example 1.

7 and 8, it can be seen that the texture is uniformly formed in Example 1 as compared with Comparative Example 1 in which the wet blast treatment was not performed.

In addition, when comparing the results of Condition 1 and Condition 2, when slicing with the fixed abrasive method, the larger the grain size of the abrasive used in the wet blasting treatment, the unevenness exists uniformly over the entire surface. It can be seen that a fine texture is formed.

Furthermore, after the wet blasting treatment of condition 1, the surface roughness when etching with acid is Ra: 0.423 μm, Rz: 6.573 μm. When the etching treatment with acid is performed after wet blasting treatment of condition 2 The surface roughness is Ra: 0.738 μm, Rz: 10.173 μm, and it can be seen that the surface roughness after etching can be controlled by changing the grain size of the abrasive grains used in the wet blast treatment.

(Confirmation of cleaning effect)
Next, in order to confirm the cleaning effect of the semiconductor wafer that has undergone the fixed abrasive grain slicing step and the damaged layer forming step of wet blasting, a semiconductor wafer was manufactured as follows. The present invention is not limited to these examples.

(Example 2)
After a polycrystalline silicon wafer having a wafer thickness of 180 μm is cut out from the polycrystalline silicon ingot by a fixed abrasive method and subjected to a peeling process, the polycrystalline silicon wafer is wet-blasted only on one side under conditions 1 and 2 in FIG. Processing was carried out. Then, after washing with water and drying, the surface state of the polycrystalline silicon wafer was visually observed. That is, in order to confirm the cleaning effect by the wet blasting process, the finishing cleaning process was omitted.

(Comparative Example 2)
After a polycrystalline silicon wafer having a wafer thickness of 180 μm is cut out from the polycrystalline silicon ingot by a fixed abrasive method and subjected to a peeling process, the polycrystalline silicon wafer is wet-blasted only on one side under conditions 1 and 2 in FIG. Processing was carried out. Further, after the wet blasting process, a finishing cleaning process was performed, and after the drying process, the surface state of the polycrystalline silicon wafer was visually observed.

In the finish cleaning step performed in Comparative Example 2, preliminary cleaning, rinsing, alkaline solution cleaning, and rinsing were performed in this order, followed by drying with warm air. In preliminary cleaning and alkaline solution cleaning, a polycrystalline silicon wafer was immersed in an alkaline solution and ultrasonic waves were emitted. The alkaline solution used is 0.5-5% by weight NaOH. The used ultrasonic waves are 10 to 100 kHz and 100 to 500 W. In rinsing, a polycrystalline silicon wafer was immersed in pure water purified using an RO membrane and irradiated with ultrasonic waves. The rinse time is 2-5 minutes. In drying with warm air, the polycrystalline silicon wafer was exposed to 100 ° hot air. The drying time with warm air is 2 to 5 minutes.

(Comparative Example 3)
A polycrystalline silicon wafer having a wafer thickness of 180 μm is cut out from the polycrystalline silicon ingot by a fixed abrasive grain method, and after performing a peeling process, it is subjected to a drying process through washing with water without performing a wet blasting process and a final cleaning process. As a result, the surface state of the polycrystalline silicon wafer was visually observed.

(result)
The observation results of Example 2, Comparative Example 2, and Comparative Example 3 are shown in FIG. As shown in FIG. 9, even when Example 2 was compared with Comparative Example 2, no difference was found in the surface cleanability. In other words, when a polycrystalline silicon wafer is cut out by the fixed abrasive method, dust adheres to the manufacturing method in which the finishing cleaning process is omitted only for the wet blasting process and the manufacturing method in which the finishing cleaning process is added after the wet blasting process. There was no difference in the degree.

On the other hand, as shown in the observation result of Comparative Example 3, when the wet blast treatment and the final cleaning process were not performed, dust was adhered to the extent that the final cleaning process was necessary even after the water cleaning.

As a result, after the wet blasting process, silicon scrap generated in the slicing process, organic coolant residue used in the slicing process, and residue of the stripping solution used in the detaching process are washed away. It was confirmed that the washing process could be omitted.

In addition, when a polycrystalline silicon wafer was cut out by the free abrasive grain method, even if wet blasting was performed, the residue could not be removed unless the finish cleaning process was performed. This is because, according to the slicing process of the loose abrasive method, the cutting process of silicon generated in the slicing process, the residue of the organic coolant used in the slicing process, and the residue of the stripping liquid used in the detaching process, the slicing process In this case, wire saw waste is also added, so it seems that it cannot be washed away by wet blasting. In the wet blasting process, if the nozzle scan is repeated several times, it seems that a certain cleaning effect can be seen even in the loose abrasive method, but it is not appropriate because it becomes difficult to control the depth of the damaged layer. .

In addition, when drive blasting is performed instead of wet blasting, silicon cutting waste generated in the slicing process, organic coolant residue used in the slicing process, and residue of the stripping liquid used in the detaching process It dried and adhered to the surface of the polycrystalline silicon wafer. That is, the cleaning effect cannot be expected in the drive blast process compared to the wet blast process.

(effect)
As described above, the method for manufacturing a semiconductor wafer according to the present embodiment is a method for manufacturing a semiconductor wafer before etching with acid for texture formation, and includes the following steps.

(1) Slicing process of a fixed abrasive grain method of cutting a semiconductor wafer by cutting a crystalline ingot with a core wire in which abrasive grains are dispersed and fixed on the surface. (2) After the slicing process of a fixed abrasive grain method, the surface of the semiconductor wafer A wet blast type damaged layer forming step of forming a damaged layer on the entire surface of the semiconductor wafer by spraying a slurry of liquid and abrasive grains on the surface. (3) Next to the damaged layer forming process, Drying process to dry.

Thereby, even if the semiconductor wafer is cut out by the fixed abrasive method, a damage layer can be formed on the entire surface, and a texture can be formed even if an etching process with acid is performed. Therefore, many semiconductor wafers can be cut out from one crystalline ingot as compared with the free abrasive grain method, and the manufacturing cost of the semiconductor wafer for solar cells can be reduced.

In addition, by combining the slicing process with the fixed abrasive method and the damage layer forming process with wet blasting, the unevenness density of the texture can be freely designed by changing the particle size of the abrasive grains contained in the slurry, It is possible to freely design the depth of the damaged layer by changing the grain size of the abrasive grains contained in the slurry.

In addition, by combining the slicing process by the fixed abrasive method and the damaged layer forming process by the wet blasting process, a cleaning effect appears in the wet blasting process, so the finishing cleaning process process is performed between the damaged layer forming process and the drying process. This can save the manufacturing cost of the semiconductor wafer for the solar cell.

As described above, several embodiments of the present invention have been described. However, these embodiments are presented as examples, and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 Wire saw 11a Rotating roller 11b Rotating roller 12 Support plate 13 Basket 14 Stripping liquid 15 Nozzle

Claims

A method of manufacturing a semiconductor wafer before being etched with an acid for texture formation,
By cutting the crystalline ingot with a core wire in which abrasive grains are dispersed and fixed on the surface, a fixed abrasive grain slicing step of cutting out the semiconductor wafer;
After the fixed abrasive grain slicing step, a wet blast type damage layer forming step of forming a damage layer on the semiconductor wafer by spraying a slurry of liquid and abrasive grains on at least one surface of the semiconductor wafer When,
Next to the damage layer forming treatment, a drying step of drying the semiconductor wafer through washing with water,
Including,
A method for manufacturing a semiconductor wafer.
Between the damaged layer forming step and the drying step, a finishing cleaning treatment step with a solvent of the semiconductor wafer is omitted,
The method of manufacturing a semiconductor wafer according to claim 1.
In the damage layer forming step,
Changing the grain size of the abrasive grains contained in the slurry according to the desired uneven density of the texture,
The method of manufacturing a semiconductor wafer according to claim 1 or 2.
In the damage layer forming step,
Changing the grain size of the abrasive grains contained in the slurry according to the depth of the damage layer to be formed,
The method for producing a semiconductor wafer according to claim 1, wherein:
A semiconductor wafer before being etched with an acid to form irregularities on the surface,
It is cut out by a fixed abrasive method that cuts a crystalline ingot with a core wire with abrasive particles fixed on the surface,
After being cut out, a damage layer is formed on the surface by spraying a slurry of liquid and abrasive grains on at least one side by a wet blast method,
A semiconductor wafer characterized by