JP5368001B2 - Manufacturing method of SOI substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent SOI substrate which is easily recognized by a substrate recognition device controlling a generation of an impurity of metal and particle by a simple method. <P>SOLUTION: The method manufactures a SOI substrate where a silicon film is formed on a first surface of one main surface of the transparent insulating substrate and the unevenness is formed on a second surface of a main surface opposite to the first main surface of the transparent insulating substrate. The SOI substrate method for manufacturing includes processes of: preparing the transparent insulating substrate; finishing at least the first surface of the transparent insulating substrate like a mirror-surface; and forming a silicon film on the first surface of the transparent insulating substrate. The SOI substrate method for manufacturing has a process for forming an unevenness pattern on the second main surface of the transparent insulating substrate using a lithography method. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an SOI substrate manufacturing method, and more particularly to an SOI substrate manufacturing method in which a silicon thin film is formed on one main surface of a transparent insulating substrate.

  In order to further improve the performance of semiconductor devices, SOI (silicon on insulator, silicon on insulator) substrates have recently attracted attention. In addition, a silicon on quartz (SOQ) substrate and a silicon on glass (SOG) substrate, which are a kind of SOI substrate and whose support substrate (handle wafer) is not silicon, are TFT-LCDs and radio frequency (RF) devices, respectively. Other applications to MEMS products are expected (see Patent Document 1).

As the SOQ substrate, for example, a method has been proposed in which a silicon substrate is used as a donor wafer and a quartz substrate is used as a handle wafer to bond these different substrates together. In the bonded substrate manufactured in this manner, the quartz substrate is transparent, and thus there may be a problem in process / evaluation different from a normal SOI substrate manufactured by bonding silicon substrates together.
As one of such problems, when transporting an SOI substrate in which a silicon thin film is formed on a transparent insulating substrate such as an SOQ substrate (hereinafter, sometimes referred to as a transparent SOI substrate) on the apparatus, Problems such as difficulty in recognition by optical sensors that recognize

JP 2006-324530 A

  The present invention has been made in view of such problems, and an object thereof is to provide a transparent SOI substrate that can be easily recognized by a substrate recognition apparatus while suppressing the generation of metal impurities and particles by a simple method. To do.

In the present invention, a silicon thin film is formed on a first main surface which is one main surface of a transparent insulating substrate, and the second main surface is a main surface opposite to the first main surface of the transparent insulating substrate. A method of manufacturing an SOI substrate having irregularities formed on a main surface, at least a step of preparing a transparent insulating substrate, a step of mirror-treating at least the first main surface of the transparent insulating substrate, Forming a silicon thin film on the first main surface of the transparent insulating substrate, and forming a concavo-convex pattern on the second main surface of the transparent insulating substrate using a lithography method. The manufacturing method of the SOI substrate which has this .

As described above, when a concavo-convex pattern is formed on the back surface of the SOI substrate so as to be easily recognized by the substrate recognition apparatus using the lithography method, generation of metal impurities and particles can be suppressed.
Furthermore, since the lithography method of the present invention can use a conventional method, a new apparatus or the like is not required, so that no cost is required.
And if it is the SOI substrate manufactured in this way, the transmittance | permeability of a signal falls by diffracting and scattering the signal from the recognition apparatus using an optical sensor by the uneven | corrugated pattern in the back surface of a transparent insulating board | substrate, It is possible to prevent an adverse effect that the substrate is not recognized by the recognition device. In addition, it is possible to prevent slipping during substrate transportation.

In this case, by forming a concavo-convex pattern on the second main surface by the lithography process, the average transmittance of light in the wavelength region of 250 to 800 nm in the direction perpendicular to the main surface of the transparent insulating substrate is 10% or less. Can be .
Thus, the formation of the concave / convex pattern by lithography on the second main surface of the transparent insulating substrate is such that the average transmittance of light in the wavelength region of 250 to 800 nm in the direction perpendicular to the main surface of the transparent insulating substrate is 10% or less. If it carries out so that it may become, it can make a board | substrate recognition apparatus recognize more reliably.

In the lithography process, a concavo-convex pattern may be formed on the second main surface by at least a resist coating process, an exposure process, a development process, and an etching process .
As described above, since the lithography process in the present invention can use a lithography method used in normal SOI substrate manufacturing, a special apparatus and procedure are not required, and a concavo-convex pattern can be easily formed without cost.

It is preferable that the period of the uneven pattern formed on the second main surface is 0.2 to 3 μm .
Thus, by setting the period of the concavo-convex pattern to 0.2 to 3 μm, the transmittance can be more reliably lowered to a desired transmittance by light diffraction and scattering.

In the method for manufacturing an SOI substrate according to the present invention, the lithography step can be performed at least after the silicon thin film formation step , or after the step of preparing the transparent insulating substrate, the silicon thin film. It can be performed before the forming step .
As described above, the lithography process in the present invention can be performed after or before the formation of the silicon thin film, and can be appropriately changed according to other manufacturing conditions.

In the method for manufacturing an SOI substrate according to the present invention, the silicon thin film is formed by implanting hydrogen ions, rare gas ions, or both from at least a silicon substrate or a silicon substrate having an oxide film formed on the surface. An ion-implanted layer is formed, and the ion-implanted surface of the silicon substrate or the silicon substrate on which the oxide film is formed and the first main surface of the transparent insulating substrate are adhered to each other, and the ion-implanted layer is bonded. As a boundary, the silicon substrate or a silicon substrate having an oxide film formed on the surface thereof is peeled off to form a thin film, and a silicon thin film is formed on the first main surface of the transparent insulating substrate .
In this way, if the silicon thin film is formed by peeling off after using the ion implanted layer as a boundary after the ion implantation, a thin silicon film with high crystallinity can be formed.

The transparent insulating substrate can be any of a quartz substrate, a glass substrate, and a sapphire substrate .
The transparent insulating substrate used in the method for manufacturing an SOI substrate of the present invention can be appropriately selected from these according to the purpose of the semiconductor device to be manufactured.

According to the SOI substrate manufacturing method of the present invention, an SOI substrate (transparent SOI substrate) in which a silicon thin film is formed on a transparent insulating substrate, and the back surface (the main surface on which the silicon thin film is not formed) is uneven. An SOI substrate on which a pattern is formed can be manufactured by suppressing generation of metal impurities and particles by a simple method.
And if it is the SOI substrate manufactured in this way, the recognition device recognizes the substrate by diffracting and scattering the signal from the recognition device using the optical sensor by the uneven pattern on the back surface of the transparent insulating substrate. Can be made. In addition, it is possible to prevent slipping during substrate transportation.

Hereinafter, the present invention will be described in more detail.
As described above, conventionally, an SOI substrate in which a silicon thin film is formed on a transparent insulating substrate such as an SOQ substrate is transported by an optical sensor in the form shown in FIG. For the recognition, the transparent insulating substrate has a problem that it has a high transmittance and is difficult to be recognized.

In response to such problems, the present inventors have provided the back surface of an SOI substrate (transparent SOI substrate) in which a silicon thin film is formed on a transparent insulating substrate, that is, the main surface on which the silicon thin film of the transparent insulating substrate is formed. It has been found that by roughening the main surface on the opposite side of the substrate, the signal from the recognition device can be scattered in the substrate recognition device using an optical sensor or the like, and the substrate can be easily recognized.
However, when such a rough surface of the substrate is formed by, for example, sandblasting, a large amount of abrasive grains or the like enters, and there is a problem that metal impurities are generated or particles are generated.
With respect to such problems, the present inventors can suppress the generation of metal impurities and particles by a simple method as long as the uneven pattern is formed on the back surface of the transparent insulating substrate using a lithography method. The inventors have conceived that the light transmittance can be lowered not only by scattering but also by diffraction, and a transparent SOI substrate that can be easily recognized by a recognition device can be manufactured, and the present invention has been completed.

In the present specification, of the main surfaces of the transparent insulating substrate, the main surface on the side where the silicon thin film is formed is referred to as a “first main surface” for convenience, and the main surface opposite to the first main surface is referred to as a “first main surface”. Called the “two main surfaces”.
The overall flow of the present invention will be described. A step of preparing a transparent insulating substrate, a step of mirror-treating one main surface (first main surface) of the transparent insulating substrate, and the mirror-finished first main surface A transparent SOI substrate is manufactured by a process of forming a silicon thin film thereon. In order to manufacture a transparent SOI substrate having a concavo-convex pattern formed on the back surface, it is necessary to perform lithography on the second main surface at any stage. In the present invention, the concavo-convex pattern can be formed by lithography on the second main surface side either after or before the formation of the silicon thin film.

Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings. However, the present invention is not limited to these embodiments.
FIG. 1 is a flowchart showing an example of a method for manufacturing an SOI substrate according to the present invention.
Here, an example will be described in which the concavo-convex pattern is formed by lithography on the second main surface side after the formation of the silicon thin film.

First, as shown in FIG. 1A, a transparent insulating substrate 10 is prepared (step 1-a). For example, a quartz substrate sliced from a quartz ingot can be used.
Note that the type of the transparent insulating substrate to which the present invention can be applied is not particularly limited. For example, the transparent insulating substrate can be any one of a quartz substrate, a glass substrate, and a sapphire substrate. It can be appropriately selected according to the purpose of the device.

Next, as shown in FIG. 1B, at least one main surface of the transparent insulating substrate is mirror-finished (step 1-b). Here, the mirror-finished main surface becomes the main surface on the side on which the silicon thin film is to be formed, that is, the first main surface 11. The method of this mirror surface processing is not specifically limited, It processes by combining lapping, an etching, grinding | polishing etc. suitably.
The other main surface, that is, the second main surface 12 is desirably subjected to at least a treatment for suppressing dust generation. Specifically, generation of particles or the like can be suppressed by performing etching after lapping. Moreover, you may perform a mirror surface process similarly to the 1st main surface. In this case, a technique such as double-side polishing that simultaneously processes the first main surface 11 and the second main surface 12 may be used.

  In addition, it is desirable to perform the mirror finish of the first main surface 11 of the transparent insulating substrate 10 so that the surface roughness is less than 0.7 nm in terms of RMS value. With such a surface roughness, the silicon substrate can be bonded with higher strength by bonding or the like, and when the silicon thin film is formed, the crystal of the silicon thin film is generated due to the generation of voids that are unbonded portions. It is possible to effectively prevent the deterioration of sex. On the other hand, the lower limit value of the RMS value of the surface roughness of the first main surface 11 is not particularly limited, and the higher the flatness, the better. However, there is a problem of cost in improving the flatness, and it is practically about 0.1 nm or more.

Next, a silicon thin film is formed on the first main surface 11 of the transparent insulating substrate 10. The method for forming the silicon thin film is not particularly limited. For example, the silicon thin film can be formed by a so-called ion implantation separation method as follows.
First, as shown in FIG.1 (c), the silicon substrate 20 is prepared (process 1-c). Further, if necessary, a silicon substrate having an oxide film formed on the surface may be used. In order to improve the state of bonding, it is necessary that the surface to be bonded (bonding surface) has a flatness of a certain level or more. Therefore, at least the surface to be bonded is mirror-polished or the like. For example, the flatness is preferably an RMS value of less than 0.7 nm.

Next, as shown in FIG. 1D, hydrogen ions are implanted into the silicon substrate 20 from the surface (ion implantation surface 22) to form the ion implantation layer 21 (step 1-d).
The ion-implanted layer 21 may be formed by implanting not only hydrogen ions but also rare gas ions or both hydrogen ions and rare gas ions. Other ion implantation conditions such as implantation energy, implantation dose, and implantation temperature may be appropriately selected so that a thin film having a predetermined thickness can be obtained. As a specific example, the temperature of the substrate at the time of implantation is 250 to 400 ° C., the ion implantation depth is 0.5 μm, the implantation energy is 20 to 100 keV, and the implantation dose is 1 × 10 ¹⁶ to 1 × 10 ¹⁷ / cm. It includes be ^two, but not limited thereto.
Note that a single crystal silicon substrate having an oxide film formed on the surface can be used as necessary. By using such a silicon substrate having an oxide film formed on the surface and performing ion implantation through the oxide film, an effect of suppressing channeling of implanted ions can be obtained, and variations in ion implantation depth can be further suppressed. . Thereby, a thin film with higher film thickness uniformity can be formed.

Next, as shown in FIG. 1E, the first main surface 11 of the transparent insulating substrate 10 and the ion-implanted surface 22 of the silicon substrate 20 are brought into intimate contact and bonded together (step 1-e).
The transparent insulating substrate 10 and the silicon substrate 20 are bonded to each other so that the first main surface 11 of the transparent insulating substrate 10 and the ion implantation surface 22 of the silicon substrate 20 are sufficiently flat surfaces as described above. Therefore, for example, if a synthetic quartz substrate and a silicon substrate are used, they can be bonded together by simply bringing them into close contact at room temperature and applying pressure.
However, in order to bond more firmly, it is preferable to do as follows.

That is, it is desirable to perform a surface activation process on the ion implantation surface 22 of the silicon substrate 20 and the first main surface 11 of the transparent insulating substrate 10 in advance. Surface activation treatment may be performed only on one of the ion implantation surface 22 of the silicon substrate 20 and the first main surface 11 of the transparent insulating substrate 10.
At this time, the surface activation treatment can be a plasma treatment. Thus, if the surface activation treatment is performed by plasma treatment, the surface of the substrate that has been subjected to the surface activation treatment is activated due to an increase in OH groups. Therefore, in this state, if the first main surface 11 of the transparent insulating substrate 10 and the ion-implanted surface 22 of the silicon substrate 20 are brought into close contact with each other, the substrates can be bonded more firmly by hydrogen bonding or the like. . In addition, the surface activation treatment can be performed by ozone treatment or the like, and a plurality of kinds of treatments may be combined.

  In the case of processing with plasma, a substrate subjected to cleaning such as RCA cleaning is placed in a vacuum chamber, and after introducing a plasma gas, it is exposed to high-frequency plasma of about 100 W for about 5 to 30 seconds, and the surface is subjected to plasma processing. To do. As the plasma gas, for example, when processing a single crystal silicon substrate with an oxide film formed on the surface, oxygen gas plasma, and when processing a single crystal silicon substrate with no oxide film formed on the surface, hydrogen is used. Gas, argon gas, a mixed gas thereof, or a mixed gas of hydrogen gas and helium gas can be used. In addition, nitrogen gas or the like may be used.

  When processing with ozone, a substrate subjected to cleaning such as RCA cleaning is placed in a chamber into which air is introduced, and after introducing a plasma gas such as nitrogen gas or argon gas, high frequency plasma is generated, The surface is treated with ozone by converting the oxygen in it into ozone.

  In this way, if the surfaces subjected to the surface activation treatment are used as the bonding surfaces, for example, the substrate is brought into close contact at room temperature under reduced pressure or normal pressure, the substrates can be firmly bonded without performing high temperature treatment.

In addition, after bonding this silicon substrate and a transparent insulating substrate, the heat processing process of heat-processing this bonded substrate at 100-300 degreeC can be performed.
Thus, after bonding a silicon substrate and a transparent insulating substrate, the bonded substrate is heat-treated at 100 to 300 ° C., thereby increasing the bonding strength between the silicon substrate and the transparent insulating substrate. it can. In addition, if the heat treatment is performed at such a low temperature, there is little risk of occurrence of thermal strain, cracking, peeling, or the like due to the difference in thermal expansion coefficient due to the different materials. Increasing the bonding strength can reduce the occurrence of defects in the peeling process.

Next, the silicon substrate 20 is separated by the ion-implanted layer 21, and a peeling step for thinning the silicon substrate 20 is performed to form a silicon thin film 31 as shown in FIG. 1 (f) (step 1-f). .
The separation (peeling, thinning) of the silicon substrate can be performed, for example, by applying a mechanical external force.

Next, as shown in FIG. 1G, an uneven pattern is formed on the second main surface 12 of the transparent insulating substrate 10 by a lithography method (step 1-g).
The concavo-convex pattern of the present invention can be formed by employing a known lithography method.

For example, a resist material is applied on the second main surface 12 of the transparent insulating substrate 10 by a technique such as spin coating so that the film thickness becomes 0.1 to 2.0 μm, and this is applied on a hot plate for 60 to 150. A photoresist film is formed by pre-baking at a temperature of 1 to 10 minutes, preferably 80 to 140 ° C. for 1 to 5 minutes.
Next, a mask for forming a target pattern is placed over the photoresist film, and high energy rays such as deep ultraviolet rays, excimer laser, and X-rays or electron beams are applied, for example, in an exposure amount of 1 to 200 mJ / cm ² , preferably Is irradiated so as to be 10 to 100 mJ / cm ² .
Next, post exposure baking (PEB) is performed on a hot plate at 60 to 150 ° C. for 1 to 5 minutes, preferably 80 to 140 ° C. for 1 to 3 minutes. Further, 0.1 to 5% by mass, preferably 2 to 3% by mass of an aqueous developer solution such as tetramethylammonium hydroxide (TMAH) is used for 0.1 to 3 minutes, preferably 0.5 to 2%. The target pattern is formed on the second main surface 12 of the transparent insulating substrate 10 by developing by a conventional method such as a dip method, a paddle method, or a spray method for a minute.
Next, a desired uneven pattern is formed on the second main surface 12 by etching with a CF ₄ / CHF ₃ gas or the like using the resist underlayer film on which the pattern is formed as a mask.
It is also possible to form the concavo-convex pattern by photolithography in step 1-g before steps 1-e to 1-f. In this case, since the silicon thin film is not formed, there is no influence on the silicon thin film by the lithography process.

As described above, since a conventional lithography method can be used as a method for facilitating recognition by the recognition apparatus, it is not expensive, no new procedure is required, and generation of particles can be suppressed.
Further, since a regular uneven pattern can be formed by lithography, scattering of transmitted light as shown in FIG. 5 occurs, and further diffraction occurs, and the transmittance can be efficiently lowered by both effects.

  As a result, the average transmittance of light in the wavelength region of 250 to 800 nm in the direction perpendicular to the main surface of the transparent insulating substrate 10 (that is, the thickness direction of the substrate) (hereinafter sometimes referred to as the vertical average transmittance). Is preferably 10% or less, and particularly preferably 5% or less. In order to obtain such a vertical average transmittance, by experimentally determining in advance what kind of concave / convex pattern the above-mentioned vertical average transmittance is obtained, so that the concave / convex pattern of the condition is obtained. A lithography process may be performed.

The period of the concavo-convex pattern can be set to 0.2 to 3 μm. This period can be appropriately changed to the period of the concavo-convex pattern that can effectively reduce the transmittance according to the period of transmitted light by the optical sensor.
The shape of the concave / convex pattern on the second main surface 12 is exemplified by a circular shape as shown in FIG. 3 (a) or a linear shape as shown in FIG. 3 (b). However, the transmittance can be kept down to the desired transmittance.

Through the steps described above, the SOI substrate 30 having the silicon thin film 31 on the first main surface 11 of the transparent insulating substrate 10 can be manufactured.
Note that the steps 1-a to 1-b and the steps 1-c to 1-d, which are treatments for separate substrates, may of course be reversed in order or performed in parallel.

  In this way, by performing steps 1-a to 1-g, an SOI substrate in which a silicon thin film is formed on a transparent insulating substrate having an uneven pattern on the back surface is manufactured. In the present invention, as a method for facilitating the recognition of the transparent insulating substrate in step 1-g by the recognition device, a conventional lithography method can be used, so no new device or procedure is required, and the costs are compared. Can be lowered. In addition, since the concavo-convex pattern is formed by lithography, generation of metal impurities and particles can be suppressed. As a result, it is possible to manufacture a transparent SOI substrate that prevents dust generation and the like and is easily recognized by the substrate recognition apparatus.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples of the present invention, but the present invention is not limited thereto.

Example 1
In the following manner, 30 transparent SOI substrates were manufactured according to the SOI substrate manufacturing method by the bonding method as shown in FIG.

First, a synthetic quartz substrate 10 having a diameter of 150 mm that was cut out from a synthetic quartz ingot was prepared (step 1-a).
Next, both surfaces of the synthetic quartz substrate 10 were polished (step 1-b). The flatness of both main surfaces was an RMS value of 0.6 nm.

Next, a mirror-polished single crystal silicon substrate having a diameter of 150 mm was prepared as the silicon substrate 20. A silicon oxide film layer having a thickness of 100 nm was formed on the surface of the silicon substrate by thermal oxidation (step 1-c).
Next, hydrogen ions are implanted into the silicon substrate 20 through the formed silicon oxide film layer to form a microbubble layer (ion implantation layer) 21 parallel to the surface at an average ion depth (step 1-). d). The ion implantation conditions are an implantation energy of 35 keV, an implantation dose of 9 × 10 ¹⁶ / cm ² , and an implantation depth of 0.3 μm.

Next, after placing the silicon substrate 20 ion-implanted in the plasma processing apparatus and introducing nitrogen as a plasma gas, parallel plate electrodes having a high frequency of 13.56 MHz and a diameter of 300 mm under a reduced pressure of 2 Torr (270 Pa). A high-frequency plasma treatment was performed for 10 seconds on the ion-implanted surface by applying a high-frequency power of 50 W in between. In this way, the surface activation treatment was performed on the ion implantation surface 22 of the silicon substrate 20.
On the other hand, the synthetic quartz substrate 10 is placed in a plasma processing apparatus, nitrogen gas is introduced as a plasma gas between narrow electrodes, and then a high frequency is applied between the electrodes to generate plasma, thereby causing high frequency plasma processing. For 10 seconds. In this way, the surface activation treatment was also applied to the first main surface 11 of the synthetic quartz substrate 10.

After the silicon substrate 20 and the synthetic quartz substrate 10 that have been subjected to the surface activation treatment as described above are brought into close contact with each other at the room temperature with the surface that has undergone the surface activation treatment as a bonding surface, the back surfaces of both substrates are disposed in the thickness direction. (Step 1-e).
Next, in order to increase the bonding strength, the substrate on which the silicon substrate 20 and the synthetic quartz substrate 10 were bonded was heat-treated at 300 ° C. for 30 minutes.

  Next, an external impact was applied to the ion implantation layer 21 of the silicon substrate 20, and the silicon thin film 31 was formed by sequentially separating the ion implantation layer 21 (step 1-f).

Next, a concavo-convex pattern was formed on the second main surface 12 of the synthetic quartz substrate 10 using the lithography method under the following conditions (step 1-g).
First, a resist material is applied to the back surface 12 of the synthetic quartz substrate 10 by spin coating so that the film thickness becomes 1.5 μm, and this is prebaked on a hot plate at 100 ° C. for 5 minutes to form a photoresist film. did.
Next, a mask for forming a target pattern was placed over the photoresist film, and X-rays were irradiated so that the exposure amount was 100 mJ / cm ² .
Next, post-exposure baking (PEB) was performed on a hot plate at 100 ° C. for 3 minutes. Further, using a developer of 3% by mass of tetramethylammonium hydroxide (TMAH), development was carried out by a spray method for 2 minutes to form a desired pattern on the substrate.
Next, using the resist film on which the pattern was formed as a mask, the chamber pressure substrate was etched with CF ₄ / CHF ₃ -based gas at 40.0 Pa for 60 seconds using a dry etching apparatus.
The uneven pattern at this time was a linear pattern with a period of 0.8 μm, and in this case, the linear transmittance of transmitted light having a wavelength of 850 nm was 5% or less. This linear transmittance figure was obtained by measuring the linear transmittance of transmitted light with a wavelength of 850 nm using a synthetic quartz substrate on which a silicon thin film was not formed in advance and both surfaces were polished and the above-described uneven pattern was formed. (See FIG. 2).

In this way, a transparent SOI substrate 30 having the silicon thin film 31 on the first main surface 11 of the synthetic quartz substrate 10 and the uneven pattern formed on the second main surface 12 was manufactured. When the transparent SOI substrate 30 was subjected to a recognition experiment using a substrate recognition apparatus provided in the device manufacturing apparatus, all the substrates were correctly recognized.
Further, the crystallinity of the silicon thin film 31 was sufficiently good. Further, dust generation of the entire transparent SOI substrate 30 was at the same level as that of a normal silicon mirror wafer.

(Example 2)
As in Example 1, except that in the lithography process of Step 1-g, a circular pattern with a period of 0.8 μm was formed, and 30 transparent SOI substrates were manufactured.
Even in this case, the linear transmittance of transmitted light having a wavelength of 850 nm was 5% or less when measured by the same method as described above (see FIG. 2).

In this way, a transparent SOI substrate 30 having the silicon thin film 31 on the first main surface 11 of the synthetic quartz substrate 10 and having a concavo-convex pattern formed on the second main surface 12 was manufactured. When the transparent SOI substrate 30 was subjected to a recognition experiment using a substrate recognition apparatus provided in the device manufacturing apparatus, all the substrates were correctly recognized.
Further, the crystallinity of the silicon thin film 31 was sufficiently good. Further, dust generation of the entire transparent SOI substrate 30 was at the same level as that of a normal silicon mirror wafer.

(Comparative example)
Similar to the measurement of the linear transmittance of the transmitted light in Example 1 and Example 2, except that the linear transmittance of the transmitted light having a wavelength of 850 nm was measured using a synthetic quartz substrate on which no concavo-convex pattern was formed. It was 90% or more (see FIG. 2). Therefore, this was not recognized when a recognition experiment was performed using the substrate recognition apparatus.

  As described above, as shown in FIG. 2, by forming a concavo-convex pattern on the back surface of the transparent insulating substrate by using a lithography method, the linear transmittance of transmitted light is 5 after formation compared to before formation of the concavo-convex pattern (90% or more). % Or less. Therefore, a transparent insulating substrate that can be easily recognized by the substrate recognition device can be manufactured.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

It is a flowchart which shows an example of the manufacturing method of the SOI substrate which concerns on this invention. It is a linear transmittance | permeability measurement result of the transparent insulation board | substrate before uneven | corrugated pattern formation, and the transparent insulation board | substrate after forming a circular and linear pattern. It is a figure showing the example of the shape of the uneven | corrugated pattern of this invention. It is a schematic diagram of substrate recognition using an optical sensor. It is a schematic diagram of the light scattering by an uneven | corrugated pattern.

Explanation of symbols

10 ... Transparent insulating substrate,
11 ... 1st main surface, 12 ... 2nd main surface,
20 ... silicon substrate,
21 ... Ion implantation layer, 22 ... Ion implantation surface,
30 ... Transparent SOI substrate 31 ... Silicon thin film.

Claims (5)

A silicon thin film is formed on the first main surface which is one main surface of the transparent insulating substrate, and irregularities are formed on the second main surface which is the main surface opposite to the first main surface of the transparent insulating substrate. A method of manufacturing an SOI substrate formed with:
Preparing a transparent insulating substrate;
Mirror-treating at least the first main surface of the transparent insulating substrate;
Forming a silicon thin film on the first main surface of the transparent insulating substrate,
Forming a concavo-convex pattern on the second main surface of the transparent insulating substrate using a lithography method,
The lithography process is to form a concavo-convex pattern on the second main surface by at least a resist coating process, an exposure process, a development process, and an etching process,
By forming a concavo-convex pattern on the second main surface by the lithography process, the average transmittance of light in the wavelength region of 250 to 850 nm in the direction perpendicular to the main surface of the transparent insulating substrate is 10% or less. to,
The period of the concavo-convex pattern formed on the second main surface is 0.2 to 3 μm,
A method for manufacturing an SOI substrate, wherein the uneven pattern is a circular or linear pattern . The method for manufacturing an SOI substrate according to claim 1 , wherein the lithography process is performed at least after the silicon thin film forming process. 2. The method for manufacturing an SOI substrate according to claim 1 , wherein the lithography step is performed after the step of preparing the transparent insulating substrate and before the step of forming the silicon thin film. Forming the silicon thin film, at least,
A silicon substrate or a silicon substrate with an oxide film formed on the surface is implanted with hydrogen ions or rare gas ions or both from the surface to form an ion implantation layer.
The silicon substrate or the surface of the silicon substrate on which the oxide film is formed and the ion-implanted surface of the silicon substrate and the first main surface of the transparent insulating substrate are adhered and bonded together,
The silicon substrate or the silicon substrate having an oxide film formed on the surface thereof is peeled and thinned with the ion implantation layer as a boundary, and a silicon thin film is formed on the first main surface of the transparent insulating substrate. The method for manufacturing an SOI substrate according to any one of claims 1 to 3 . The transparent insulating substrate, a quartz substrate, a glass substrate, an SOI substrate manufacturing method according to any one of claims 1 to 4, characterized in that either a sapphire substrate.

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