JP2008288556A - Manufacturing method of bonded substrate - Google Patents

Abstract

In manufacturing a bonded substrate using an insulating substrate as a handle wafer, the rear surface of the bonded substrate (corresponding to the back surface of the insulating substrate) is roughened so that the substrate can be removed after transporting and mounting. In the bonded substrate which is easy and further uses a transparent insulating substrate as a handle wafer, a method for manufacturing a bonded substrate with a simple surface identification is provided as in the silicon semiconductor wafer process.
A method of manufacturing a bonded substrate in which an insulating substrate is used as a handle wafer and a donor wafer is bonded to the surface of the insulating substrate, wherein at least a back surface of the insulating substrate is subjected to sandblasting. Manufacturing method of bonded substrate to be applied.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing a bonded substrate, and more particularly to a method for manufacturing a bonded substrate in which a silicon thin film is formed on the surface of an insulating substrate.

  In order to further improve the performance of semiconductor devices, a silicon on insulator (SOI) substrate has recently attracted attention. In addition, silicon on quartz (SOQ) substrate, silicon on glass (SOG) substrate, etc., where the support substrate (handle wafer) is not silicon, are applied to TFT-LCDs, high frequency (RF) devices, and other MEMS products, respectively. Is expected.

  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 (see Patent Document 1). In the bonded substrate thus manufactured, the quartz substrate is usually manufactured by double-side polishing in which the front surface and the back surface are simultaneously polished, so that the back surface is also a mirror surface and is manufactured by bonding silicon substrates together. In some cases, a problem in process / evaluation differs from that of a normal SOI substrate.

  One of the problems is that when the SOQ substrate is transported and fixed on the apparatus, the wafer is in close contact with the stage, making it difficult to remove it from the stage. Can be difficult, and can lead to erroneous operation in handling.

JP 2006-324530 A

  The present invention has been made in view of such problems, and in manufacturing a bonded substrate using an insulating substrate as a handle wafer, the back surface of the bonded substrate (corresponding to the back surface of the insulating substrate) is used. Roughening makes it easy to remove after transporting and mounting. Furthermore, in the bonded substrate using a transparent insulating substrate as a handle wafer, the surface can be easily identified in the same way as the silicon semiconductor wafer process. An object of the present invention is to provide a method for manufacturing a laminated substrate.

  In order to solve the above-described problems, the present invention provides a method for manufacturing a bonded substrate in which an insulating substrate is used as a handle wafer and a donor wafer is bonded to the surface of the insulating substrate. Provided is a method for manufacturing a bonded substrate, characterized in that a sandblast treatment is performed on the back surface of the substrate.

  As described above, in the method of manufacturing a bonded substrate in which an insulating substrate is used for the handle wafer and the donor wafer is bonded to the surface of the insulating substrate, the back surface of the insulating substrate is subjected to sand blasting, thereby insulating the insulating substrate. The back surface of the conductive substrate can be roughened and can be easily removed after transporting and placing by roughening the surface. For example, in the bonded substrate having a transparent insulating substrate as a handle wafer, silicon As in the semiconductor wafer process, the surface can be easily identified.

The present invention also relates to a method of manufacturing a bonded substrate in which an insulating substrate is used as a handle wafer and a donor wafer is bonded onto the surface of the insulating substrate, and at least on the surface of the insulating substrate. Provided is a method for manufacturing a bonded substrate, comprising: preparing a bonded substrate on which a silicon thin film is formed, and subjecting the back surface of the bonded substrate to sandblasting.
In this way, it is easy to remove after transporting and mounting by roughening the surface. Further, in the bonded substrate having the transparent insulating substrate as the handle wafer, the same process as that of the silicon semiconductor wafer is performed. The identification of the surface becomes simple.

The present invention is also a method of manufacturing a bonded substrate in which a silicon thin film is formed on the surface of an insulating substrate and the back side of the insulating substrate is roughened, and at least on the surface of the insulating substrate. A method for producing a bonded substrate comprising preparing a bonded substrate on which a silicon thin film is formed, applying a protective tape on at least the silicon thin film of the bonded substrate, and subjecting the back surface of the insulating substrate to sandblasting I will provide a.
As described above, since the protective tape is applied to at least the silicon thin film of the bonded substrate and then the sandblasting process is performed on the back surface of the insulating substrate. In the bonded substrate which is easy to remove and further uses a transparent insulating substrate as a handle wafer, the surface can be easily identified as in the process of the silicon semiconductor wafer. It is possible to prevent the surface of the silicon thin film from being subjected to sandblasting.

At this time, after the sandblast treatment is performed on the back surface of the insulating substrate, the protective tape is peeled off, and the bonded substrate can be treated with a solution containing hydrofluoric acid.
After the sandblast treatment, the protective tape is peeled off, and the bonded substrate is treated with a solution containing hydrofluoric acid, so that dust generation from the irregularities on the back surface subjected to the sandblast treatment can be effectively suppressed. Therefore, the occurrence of particle contamination can be suppressed.

  The present invention is also a method of manufacturing a bonded substrate in which a silicon thin film is formed on the surface of an insulating substrate and the back side of the insulating substrate is roughened, and at least on the surface of the insulating substrate. A bonded substrate on which a silicon thin film is formed is prepared, an organic film is formed on at least the silicon thin film of the bonded substrate, and the back surface of the insulating substrate is subjected to sand blasting, and then the bonded substrate is hydrofluoric acid. A method for producing a bonded substrate is provided, wherein the organic film is removed after the treatment with a solution containing.

As described above, in the method for manufacturing a bonded substrate according to the present invention, an organic film is formed on at least the silicon thin film of the bonded substrate, and the back surface of the insulating substrate is subjected to sand blasting, and then the bonded substrate is subjected to hydrofluoric acid. It is characterized by removing the organic film after treatment with a solution containing hydrogen, so that when treated with a solution containing hydrofluoric acid, the silicon thin film is covered with the organic film, and the solution containing hydrofluoric acid Can be prevented from coming into direct contact with the silicon thin film.
Therefore, even when the bonded substrate has HF defects, when the bonded substrate is treated with a solution containing hydrofluoric acid, the hydrofluoric acid penetrates through the HF defects from the surface side of the silicon thin film, and the silicon thin film It is possible to prevent the defects from being enlarged by etching the underlying insulating substrate (quartz substrate or the like).
Further, it is possible to effectively prevent the hydrofluoric acid from permeating between the insulating substrate and the silicon thin film formed thereon and peeling off the silicon thin film.

  The present invention is also a method of manufacturing a bonded substrate in which a silicon thin film is formed on the surface of an insulating substrate and the back side of the insulating substrate is roughened, and at least on the surface of the insulating substrate. A bonded substrate on which a silicon thin film is formed is prepared, an organic film is formed on at least the silicon thin film of the bonded substrate, a protective tape is applied on the organic film, and a sandblast treatment is performed on the back surface of the insulating substrate. Then, the protective tape is peeled off, the bonded substrate is treated with a solution containing hydrofluoric acid, and then the organic film is removed.

Thus, in the method for manufacturing a bonded substrate of the present invention, at least a bonded substrate in which a silicon thin film is formed on the surface of an insulating substrate is first prepared, and at least on the silicon thin film of the bonded substrate. Since an organic film is formed and a protective tape is applied on the organic film, the protective tape is applied to the organic film and is not applied directly to the silicon thin film.
Therefore, when the protective tape is peeled off after the back surface of the insulating substrate is sandblasted, it is possible to prevent damage such as peeling on the surface of the silicon thin film by peeling off the protective tape.
Furthermore, since the organic film is removed after the bonded substrate is treated with a solution containing hydrofluoric acid, the silicon thin film is covered with the organic film and treated with the solution containing hydrofluoric acid. It can be very effectively prevented that the solution directly touches the silicon thin film to expand the HF defect or peel off the silicon thin film.

The insulating substrate can be any of a quartz substrate, a glass substrate, a sapphire substrate, and an alumina substrate.
As described above, the insulating substrate can be any one of a quartz substrate, a glass substrate, a sapphire substrate, and an alumina substrate. In the case of manufacturing an SOQ substrate, an SOG substrate, an SOS substrate, and an SOA (Silicon on Allumina) substrate, the present invention is used. Is particularly preferred.

The organic film is preferably formed by coating.
As described above, if the organic film is formed by coating, the organic film can be easily formed, which is convenient.

At this time, the organic film can be a photoresist film.
If the organic film is a photoresist film, the photoresist is often used conventionally, and the organic film can be easily formed.

The organic film can be removed by treatment with ozone water, sulfuric acid, hot sulfuric acid, sulfuric acid / hydrogen peroxide, alcohol, or acetone, or by oxygen plasma treatment or ultraviolet treatment.
In this way, the organic film can be easily removed by treating with ozone water, sulfuric acid, hot sulfuric acid, sulfuric acid / hydrogen peroxide, alcohol, or acetone, or by performing oxygen plasma treatment or ultraviolet treatment. Can be removed.

The protective tape can be a dicing tape.
In this way, the protective tape can be a dicing tape, and the silicon thin film or the like can be sufficiently protected from the sandblasting process.

  The preparation of the bonded substrate includes at least a silicon substrate or a silicon substrate having an oxide film formed on the surface, by implanting hydrogen ions or rare gas ions or both from the surface to form an ion implantation layer, An ion-implanted surface of a silicon substrate or a silicon substrate having an oxide film formed on the surface and the surface of the insulating substrate to be bonded to the ion-implanted surface are adhered and bonded together, with the ion-implanted layer as a boundary, The bonded substrate can be prepared by mechanically peeling a silicon substrate or a silicon substrate having an oxide film formed on the surface to form a thin film, and forming a silicon thin film on the surface of the insulating substrate.

In addition, the preparation of the bonded substrate includes at least a silicon substrate or a silicon substrate having an oxide film formed on the surface, by implanting hydrogen ions or rare gas ions or both from the surface to form an ion implantation layer, Surface activation treatment is performed on at least one of the surface of the silicon substrate or the silicon substrate having an oxide film formed on the surface and the surface of the insulating substrate to be bonded to the ion-implanted surface, and the silicon substrate or A silicon substrate having an oxide film formed on the surface thereof and the surface of the insulating substrate adhered and bonded together, and the silicon substrate or silicon having an oxide film formed on the surface with the ion implanted layer as a boundary The substrate is mechanically peeled to form a thin film, and a silicon thin film is formed on the surface of the insulating substrate to form the bonded substrate. It is possible to prepare.
If an insulating substrate having a roughened back surface is used at the time of mechanical peeling here, the thickness of the transferred silicon varies due to local differences in stress during the mechanical peeling. Because it is not desirable. Specifically, when controlling the peeling speed by bringing the stiffening plate into close contact with the back surface during mechanical peeling, the stress at the time of mechanical peeling is different because the adhesion force with the stiffening plate is locally different. Are locally different, and the thickness of the transferred silicon also varies.

  By doing so, it is possible to prepare a bonded substrate of different kinds of materials in which a silicon thin film is formed on the surface of an insulating substrate, and to be suitable for applications such as TFT-LCDs and radio frequency (RF) devices. Become.

Further, the surface of the silicon thin film can be mirror-finished before and / or after the sandblast treatment.
As described above, the surface of the silicon thin film for producing a device or the like may be mirror-finished before the sandblast treatment, and in the present invention, the mirror-finished state can be maintained even after sandblasting with the organic film and the protective tape. Of course, the surface of the silicon thin film can be mirror-finished after the sandblast treatment.

  With such a method of manufacturing a bonded substrate of the present invention, even a bonded substrate using an insulating substrate as a handle wafer can be easily removed after being transported and placed by roughening the surface. In addition, with the bonded substrate using a transparent insulating substrate as a handle wafer, a bonded substrate with a simple surface identification can be manufactured as in the silicon semiconductor wafer process.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
FIG. 1 is a process diagram showing an example of a process of a method for manufacturing a bonded substrate according to the present invention.
The overall flow will be described. First, a bonded substrate in which a silicon thin film is formed on the surface of an insulating substrate is prepared (step 1). An organic film is formed on the silicon thin film on the prepared bonded substrate (step 2), and a protective tape is further stuck thereon (step 3). Then, sandblasting is performed to roughen the back surface of the bonded substrate (step 4), the protective tape is peeled off (step 5), and the bonded substrate is treated with a solution containing hydrofluoric acid to etch the back surface of the bonded substrate. After the treatment (step 6), the organic film is removed (step 7), and a bonded substrate with a roughened back surface is obtained by suppressing the occurrence of particle contamination and the like.

Hereinafter, each step will be further described in detail.
(Process 1)
First, a bonded substrate 60 in which a silicon thin film 61 is formed on the surface of the insulating substrate 20 is prepared. That is, a silicon substrate is prepared as a donor wafer and an insulating substrate is prepared as a handle wafer, and these are bonded together.
FIG. 2 shows an example of a procedure for manufacturing this bonded substrate. As shown in FIG. 2A, first, a silicon substrate 10 and an insulating substrate 20 are prepared.
The donor wafer can be a silicon substrate having an oxide film formed on the surface. If these materials are selected as the donor wafer, a bonded substrate having a silicon thin film can be manufactured.
Further, as the insulating substrate 20 which is a handle wafer, for example, a quartz substrate, another glass substrate, a sapphire substrate, or an alumina substrate can be used. These are not particularly limited as long as they are transparent and insulating substrates. It can be appropriately selected according to the purpose of the semiconductor device to be manufactured. Here, a case where a quartz substrate is used will be described as an example.

Next, as shown in FIG. 2B, hydrogen ions are implanted from the surface (ion implantation surface) 12 of the silicon substrate 10 to form an ion implantation layer 11.
The ion-implanted layer 11 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.
Note that if ion implantation is performed through an oxide film using a silicon substrate having an oxide film formed on the surface, 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. 2C, a surface activation process is performed on the ion-implanted surface 12 of the silicon substrate 10 and the bonded surface 22 of the insulating substrate 20. The surface 22 to be bonded to the insulating substrate 20 is the surface to be bonded to the silicon substrate 10 in the following procedure.
Of course, the surface activation process may be performed only on one of the surface 12 into which the ions are implanted of the silicon substrate 10 and the surface 22 on which the insulating substrate 20 is bonded.
At this time, the surface activation treatment can be performed by, for example, oxygen plasma treatment. A wafer subjected to cleaning such as RCA cleaning is placed in a vacuum chamber, and after introducing a plasma gas (oxygen gas), the surface is subjected to plasma treatment by exposure to high-frequency plasma of about 100 W for about 5 to 30 seconds.

  Note that the plasma gas is not limited to oxygen gas. In addition, for example, hydrogen gas, argon gas, a mixed gas thereof, or a mixed gas of hydrogen gas and helium gas can be used. Further, an inert gas such as nitrogen gas may be used. You can select the one that meets your requirements.

In this way, the surface of each of the substrates 10 and 20 that has been subjected to the surface activation process is activated by increasing OH groups. Therefore, in this state, if the surface 12 into which the silicon substrate is ion-implanted and the surface 22 to which the insulating substrate is bonded are brought into close contact with each other, the wafer can be bonded more firmly by hydrogen bonding or the like.
In addition, it is also possible to perform the following bonding process, without performing this surface activation process.

Next, as shown in FIG. 2D, the ion-implanted surface 12 of the silicon substrate and the bonding surface 22 of the insulating substrate are adhered to each other and bonded together.
In this way, if the surfaces subjected to the surface activation treatment are used as the bonding surface, for example, if the wafers are brought into close contact at room temperature under reduced pressure or normal pressure, both wafers can withstand subsequent mechanical peeling without being subjected to high temperature treatment. It can be bonded firmly enough to obtain.

Note that after the step of bringing the silicon substrate 10 and the insulating substrate 20 into close contact, a heat treatment step of heat-treating the attached wafer at 100 to 400 ° C. may be performed.
By performing such heat treatment, the bonding strength between the silicon substrate 10 and the insulating substrate 20 can be increased. In particular, when the heat treatment temperature is 100 to 300 ° C., there is little risk of thermal distortion, cracking, peeling, and the like due to differences in thermal expansion coefficients even when substrates of different materials are bonded. If the bonding strength is increased, the occurrence of defects in the peeling process can be reduced.

Thereafter, as shown in FIG. 2E, for example, the pulling member 40 is brought into close contact with the silicon substrate 10 to hold the silicon substrate 10, and the insulating substrate 20 is held by the pulling member 50.
As the pulling member, a member composed of one or more suction cups, a member composed of a porous material, and adsorbed on each of the substrates 10 and 20 by vacuum suction, etc. can be used. It is not limited to.

Next, as shown in FIG. 2 (F), an external impact is applied from one end of the ion implantation layer 11 of the silicon substrate 10 on the side where the tensile member 40 is brought into close contact, and the tensile members 40 and 50 are used. By pulling the silicon substrate 10 and the insulating substrate 20, the silicon substrate 10 and the insulating substrate 20 are sequentially moved from one end (exfoliation start point) to which the external impact is applied to the other end in the ion implantation layer 11. The silicon substrate 10 is thinned away.
As described above, a bonded substrate 60 in which the silicon thin film 61 is formed on the surface of the insulating substrate 20 can be obtained as shown in FIG.

(Process 2)
After preparing the bonded substrate 60 in Step 1, an organic film 70 is formed on the silicon thin film 61 as shown in (Step 2) of FIG.
The material of the organic film 70 is not particularly limited, but is preferably resistant to hydrofluoric acid. For example, a photoresist is suitable. In the following description, it is assumed that the organic film 70 is formed of a photoresist.
At this time, it is better to form the organic film 70 so as to cover the entire silicon thin film 61 so as to cover the silicon thin film 61.
In these processes, the bonded substrate 60 is treated with a solution containing hydrofluoric acid in the subsequent step 6. At this time, HF defects existing in the silicon thin film 61 are expanded, or the silicon thin film 61 is insulated. This is to prevent peeling from 20.

When the etching process is performed after the sandblasting process without forming the organic film 70, for example, when the insulating substrate is a quartz substrate, when the HF defect exists in the silicon thin film as described above, the surface of the silicon thin film passes through the defect. When hydrofluoric acid permeates, the quartz substrate existing under the silicon thin film is etched and the defects are enlarged. This causes a device failure or the like.
Further, when hydrofluoric acid permeates between the silicon thin film and the quartz substrate, the portion of the quartz substrate is etched, and the silicon thin film is peeled off.

  However, as shown in FIG. 1 (step 2), an organic film 70 resistant to hydrofluoric acid is formed in advance so as to cover the silicon thin film 61 and further cover the silicon thin film 61. 6, even if the bonded substrate 60 is etched, the silicon thin film 61 is surrounded by the organic film 70, so that hydrofluoric acid permeates from the surface of the silicon thin film 61 through HF defects and the like. If the quartz substrate 20 is not etched to enlarge the defects, hydrofluoric acid enters between the silicon thin film 61 and the quartz substrate 20, and the quartz substrate 20 is not etched and the silicon thin film 61 is not peeled off.

The method for forming the organic film 70 is not particularly limited, but can be formed by coating, for example. A coating is preferable because it can be easily formed.
In applying a photoresist, a HMDS process may be performed as a pretreatment. By performing the HMDS process, the adhesion between the photoresist film to be formed later and the silicon thin film 61 can be improved.
Furthermore, in order to improve the adhesion, it is also possible to perform a process such as soft baking after forming the photoresist film.

(Process 3)
Next, the protective tape 80 is pasted on the organic film 70. Thus, if the protective tape 80 is not directly applied to the silicon thin film 61 but is applied to the organic film 70, the surface of the silicon thin film 61 is peeled off together when the protective tape 80 is removed in the subsequent step 5. Therefore, no damage is introduced into the silicon thin film 61.
The protective tape 80 is not particularly limited as long as it can prevent the silicon thin film 61 side of the bonded substrate 60 from being damaged when the sandblasting process is performed in the next step 4. For example, a dicing tape can be used.

(Process 4)
As described above, the organic film 70 is formed on the silicon thin film 61 formed on the front surface side of the insulating substrate 20, and the back surface side (that is, the bonded substrate 60 to which the protective tape 80 is attached) The surface of the insulating substrate 20 is intentionally roughened by sandblasting. As a result, the back side can be sensed by an optical sensor or the like.
The sandblasting process in this step 4 is not particularly limited, and is performed, for example, by applying particles such as alumina to the back side using an apparatus similar to the conventional one.
On the other hand, since the protective tape 80 is affixed to the front surface side (that is, the side where the silicon thin film 61 is formed) of the bonded substrate 60, unlike the back surface side, it is not damaged or roughened.

(Process 5)
After the sandblast treatment, the protective tape 80 is peeled off in preparation for an etching treatment with a solution containing hydrofluoric acid in the next step 6. Here, the protective tape 80 is applied to the organic film 70, not the silicon thin film 61. Therefore, when the protective tape 80 is peeled off from the organic film 70, the surface of the silicon thin film 61 is not peeled off and the silicon thin film 61 is not damaged.

(Step 6)
In step 6, the bonded substrate 60 is treated with a solution containing hydrofluoric acid. That is, the back surface side (the back surface side of the insulating substrate 20) of the bonded substrate 60 that has been subjected to the sandblast treatment is etched with a solution containing hydrofluoric acid. This method is not particularly limited, and can be performed, for example, by immersing the bonded substrate 60 in a solution containing hydrofluoric acid. And by performing an etching process in this way, it can suppress that a dust generation generate | occur | produces from the uneven surface roughened by the sandblast process.
At this time, the solution used for the etching process is not particularly limited as long as it contains hydrofluoric acid so that the back side of the insulating substrate 20 such as a quartz substrate or a glass substrate can be etched. For example, hydrofluoric acid, buffered hydrofluoric acid aqueous solution, or the like can be used, and the concentration thereof can be determined as appropriate. For example, an experiment can be repeated to select a material that can be etched appropriately and can suppress generation of dust from unevenness due to sandblasting.

  In addition, while the back surface side (the back surface side of the insulating substrate 20) of the bonded substrate 60 is etched in this manner, the front surface side (the silicon thin film 61 side) is an organic film resistant to hydrofluoric acid. Since the organic film 70 serves as a mask, the solution containing hydrofluoric acid does not directly contact the surface of the silicon thin film 61. Therefore, even if HF defects exist in the silicon thin film 61, hydrofluoric acid permeates from the surface side of the silicon thin film 61 through the HF defects to the insulating substrate 20, and etches the insulating substrate 20 such as a quartz substrate. As a result, it is possible to prevent the defects from expanding very effectively.

  Furthermore, as shown in (Step 2) of FIG. 1, if the organic film 70 is formed so as to fill the bonding boundary (bonding surface) between the silicon thin film 61 and the insulating substrate 20, this can be achieved. A solution containing hydrofluoric acid does not directly contact the bonding boundary. Therefore, it is possible to prevent hydrofluoric acid from permeating from the bonding boundary, etching the insulating substrate 20, and peeling off the silicon thin film 61 from the insulating substrate 20.

(Step 7)
Thereafter, the organic film 70 that has served as a mask in the etching process of Step 6 is removed. Although this removal method is not particularly limited, for example, it can be removed by treatment with ozone water, sulfuric acid, hot sulfuric acid, sulfuric acid / hydrogen peroxide, alcohol, acetone or the like. As another method, the organic film 70 may be removed by oxygen plasma treatment or ultraviolet treatment (UV treatment). It is sufficient if the organic film 70 formed on the silicon thin film 61 can be removed without particularly damaging the silicon thin film 61 and can be determined as appropriate depending on the material of the organic film 70 and the like.

  By performing at least Step 1 to Step 7 as described above, a silicon thin film 61 is formed on the surface of the insulating substrate 20, and a bonded substrate 60 ′ having a roughened back surface side of the insulating substrate 20 is formed. Obtainable. This bonded substrate 60 ′ is not damaged or peeled off from the insulating substrate 20 in the silicon thin film 61, and even if HF defects exist, the defects may be enlarged in the above manufacturing process. Absent. Furthermore, while the back surface side of the insulating substrate 20 is properly exposed, dust generation can be effectively suppressed, and particle contamination and the like are prevented from occurring in a later process. Will be able to.

  In the description of the method for manufacturing a bonded substrate of the present invention, as shown in FIG. 1, the manufacturing method performed in steps 1 to 7 has been described here. Still other steps can be added. For example, after the step 5 of peeling off the protective tape 80, after performing a step of washing with water, ultrasonic water, or the like, the etching treatment with a solution containing hydrofluoric acid in step 6 can be performed.

Alternatively, the surface of the silicon thin film 61 on which the device is manufactured can be mirror-finished somewhere before the step 4 of performing the sandblast treatment. As described above, even if the mirror finishing is performed before the sand blasting process, the silicon thin film 61 is protected by the protective tape 80 via the organic film 70. Therefore, the mirrored surface is not damaged during the sand blasting process. Since the protective tape 80 is not directly attached to the silicon thin film 61, the surface of the silicon thin film 61 is not peeled off even if the protective tape 80 is peeled off after the sandblasting process, so that the mirror surface state is sufficiently maintained. Can do.
Naturally, the surface of the silicon thin film 61 can be mirror-finished again after the sandblasting process, or the mirroring process may be performed only after the sandblasting process. It can be determined as appropriate in consideration of cost, labor, time required for work, and the like.

As another embodiment of the present invention, the protective film 80 is not used, the organic film 70 is formed on the silicon thin film 61, the back surface of the insulating substrate 20 is subjected to sandblasting, and then hydrofluoric acid is used. There is also a method of removing the organic film 70 after performing the etching process. That is, this is a method of performing steps 1, 2, 4, 6, and 7 in FIG. Also by this method, naturally, the solution containing hydrofluoric acid does not come into direct contact with the silicon thin film 61, and it is possible to prevent the HF defect from expanding and the silicon thin film 61 from peeling off.
In this case, it is preferable that the organic film 70 is resistant to such an extent that the organic film 70 can serve as a protective tape in the sandblasting process, or a film whose thickness is adjusted.

As still another embodiment, it is possible to apply the protective tape 80 to the front surface side (the surface of the silicon thin film) of the bonded substrate without forming the organic film 70, and to perform the sandblast treatment on the back surface. As a matter of course, the protective tape 80 can effectively prevent the surface of the silicon thin film from being damaged during the sandblasting process.
In this case, as the protective tape 80, it is preferable to select an appropriate tape that takes adhesiveness into consideration so that the protective tape 80 is not easily peeled off when the protective tape 80 is peeled off from the surface of the silicon thin film.
And after peeling off the protective tape 80, it can also process with the solution containing a hydrofluoric acid for the suppression of the dust generation from the unevenness | corrugation of a back surface as needed.

  In addition, a method for manufacturing a bonded substrate in which the back surface of the insulating substrate 20 is simply subjected to a sandblasting process can be mentioned. In the first place, such a sandblasting process is performed on the back surface of the insulating substrate 20 as a handle wafer, so that it is easy to remove after transporting and mounting by roughening the surface. Further, the transparent insulating substrate can be used as a handle wafer. Further, in the bonded substrate, a bonded substrate with a simple surface identification can be obtained as in the silicon semiconductor wafer process.

Hereinafter, the method for producing a bonded substrate of the present invention will be described more specifically with reference to examples and comparative examples.
Example 1
The method for manufacturing a bonded substrate of the present invention is carried out to manufacture a bonded substrate having a roughened back surface.
A silicon substrate having a diameter of 150 mm was prepared as a donor wafer, and a silicon oxide film having a thickness of 100 nm was formed on the surface by thermal oxidation. Hydrogen ions were implanted into this substrate through a silicon oxide film to form an ion implantation layer. 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 nm.
A quartz substrate having a diameter of 150 mm was prepared as a handle wafer.

Next, using a plasma processing apparatus, nitrogen gas was introduced as a plasma gas, and a surface activation process was performed on the ion-implanted surface of the prepared silicon substrate and the surface of the quartz substrate.
Then, these substrates are bonded together at room temperature and heat-treated at 300 ° C. for 30 minutes, and then a part of the silicon substrate is peeled off with the ion implantation layer as a boundary using a tensile member, and a silicon thin film is formed on the surface of the quartz substrate. A bonded substrate on which was formed was produced. This is a sample wafer.

A photoresist was applied to the surface of the sample wafer on the silicon thin film side so as to cover the entire silicon thin film, dried, and soft baked.
Then, a dicing tape was attached as a protective tape on the photoresist film, and a sandblast treatment was performed on the back side of the sample wafer. Alumina particles were used for the sandblast treatment.

After the sandblast treatment, the dicing tape was peeled off from the photoresist film and washed with ultrasonic water. Then, the back surface side (the back surface side of the quartz substrate) of the sample wafer subjected to the sandblast treatment was etched by immersing the sample wafer in a hydrofluoric acid solution with the photoresist film attached.
Thereafter, the photoresist film was removed with acetone to produce a bonded substrate having a roughened back surface.

  Thus, the back surface of the bonded substrate manufactured by the manufacturing method of the present invention could be detected by the optical sensor. Furthermore, when the state of the front and back surfaces was evaluated, no particles were observed on the back side subjected to the sand blast treatment, and no peeling of the silicon thin film was observed on the front side, and a high-quality bonded substrate It was found that was obtained.

(Example 2)
A sample wafer similar to that in Example 1 was prepared.
A dicing tape as a protective tape was directly attached to the surface of the sample wafer on the silicon thin film side, and sandblasting was performed on the back side of the sample wafer in the same manner as in Example 1.
After the sandblast treatment, the dicing tape was peeled off from the silicon thin film and washed with ultrasonic water. Then, by immersing the sample wafer in a hydrofluoric acid solution, the back surface side (the back surface side of the quartz substrate) of the sample wafer subjected to the sandblast treatment was etched to produce a bonded substrate having a rough back surface side.

  As described above, the state of the front and back surfaces of the bonded substrate manufactured by the manufacturing method of the present invention was evaluated. On the front surface side, it was confirmed that the silicon thin film was partially peeled off from the quartz substrate or the surface of the silicon thin film was peeled off. However, it is easy to remove it after transporting and mounting by roughening the surface, and in the bonded substrate having a transparent insulating substrate as a handle wafer, the surface of the bonded substrate is the same as that of the silicon semiconductor wafer. A bonded substrate with a simple identification could be obtained.

  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.

  For example, in the above example, the quartz substrate is used as the insulating substrate, but similarly, other transparent glass substrates can be used as the insulating substrate.

It is process drawing which shows an example of the process of the manufacturing method of the bonded substrate board of this invention. It is process drawing which shows an example of the bonding procedure of a silicon substrate and an insulating substrate.

Explanation of symbols

10 ... Silicon substrate, 11 ... Ion implantation layer, 12 ... Ion implantation surface,
20 ... Insulating substrate, 22 ... Surface to be bonded,
40, 50 ... tensile member, 60, 60 '... bonded substrate,
61 ... Silicon thin film, 70 ... Organic film, 80 ... Protective tape.

Claims (14)

  A method of manufacturing a bonded substrate in which an insulating substrate is used as a handle wafer and a donor wafer is bonded to the surface of the insulating substrate, wherein at least a back surface of the insulating substrate is subjected to sandblasting. A method for manufacturing a bonded substrate.   A method of manufacturing a bonded substrate in which an insulating substrate is used for a handle wafer and a donor wafer is bonded to the surface of the insulating substrate, wherein at least a silicon thin film is formed on the surface of the insulating substrate. A method for producing a bonded substrate, comprising: preparing a bonded substrate and then subjecting the back surface of the bonded substrate to sandblasting.   A method of manufacturing a bonded substrate in which a silicon thin film is formed on a surface of an insulating substrate and a back surface side of the insulating substrate is roughened, wherein at least a silicon thin film is formed on the surface of the insulating substrate. A method for manufacturing a bonded substrate, comprising preparing a bonded substrate, applying a protective tape on at least a silicon thin film of the bonded substrate, and subjecting the back surface of the insulating substrate to sandblasting.   4. The method for producing a bonded substrate according to claim 3, wherein the back surface of the insulating substrate is subjected to sandblasting, and then the protective tape is peeled off, and the bonded substrate is treated with a solution containing hydrofluoric acid. .   A method of manufacturing a bonded substrate in which a silicon thin film is formed on a surface of an insulating substrate and a back surface side of the insulating substrate is roughened, wherein at least a silicon thin film is formed on the surface of the insulating substrate. A laminated substrate is prepared, an organic film is formed on at least the silicon thin film of the bonded substrate, a sandblast treatment is performed on the back surface of the insulating substrate, and then the bonded substrate is treated with a solution containing hydrofluoric acid. Then, the method for manufacturing a bonded substrate is characterized in that the organic film is removed.   A method of manufacturing a bonded substrate in which a silicon thin film is formed on a surface of an insulating substrate and a back surface side of the insulating substrate is roughened, wherein at least a silicon thin film is formed on the surface of the insulating substrate. After preparing a laminated substrate, forming an organic film on at least the silicon thin film of the bonded substrate, applying a protective tape on the organic film, and subjecting the back surface of the insulating substrate to sandblasting, the protective tape A method for producing a bonded substrate, comprising: removing the organic film after removing the substrate and treating the bonded substrate with a solution containing hydrofluoric acid.   The method for manufacturing a bonded substrate according to any one of claims 3, 4, and 6, wherein the protective tape is a dicing tape.   The method for manufacturing a bonded substrate according to claim 1, wherein the insulating substrate is any one of a quartz substrate, a glass substrate, a sapphire substrate, and an alumina substrate.   The method for manufacturing a bonded substrate according to any one of claims 5 to 8, wherein the organic film is formed by coating.   The method for manufacturing a bonded substrate according to any one of claims 5 to 9, wherein the organic film is a photoresist film.   6. The organic film is removed by treatment with ozone water, sulfuric acid, hot sulfuric acid, sulfuric acid / hydrogen peroxide, alcohol, or acetone, or by oxygen plasma treatment or ultraviolet treatment. Item 11. A method for producing a bonded substrate according to any one of Items 10 to 10. Preparation of the bonded substrate is 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 having an oxide film formed on the surface thereof and the surface of the insulating substrate to be bonded to the ion-implanted surface are adhered and bonded together.
With the ion-implanted layer as a boundary, the silicon substrate or a silicon substrate having an oxide film formed on the surface is mechanically peeled to form a thin film, and a silicon thin film is formed on the surface of the insulating substrate to form the bonded substrate. It prepares, The manufacturing method of the bonded substrate as described in any one of Claims 2-11 characterized by the above-mentioned. Preparation of the bonded substrate is 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.
Surface activation treatment is performed on at least one of the surface of the silicon substrate or the surface of the insulating substrate to be bonded to the surface of the silicon substrate on which an oxide film is formed on the surface of the silicon substrate,
The silicon substrate or the surface of the silicon substrate having an oxide film formed on the surface thereof and the surface of the insulating substrate are adhered and bonded together,
With the ion-implanted layer as a boundary, the silicon substrate or a silicon substrate having an oxide film formed on the surface is mechanically peeled to form a thin film, and a silicon thin film is formed on the surface of the insulating substrate to form the bonded substrate. It prepares, The manufacturing method of the bonded substrate as described in any one of Claims 2-11 characterized by the above-mentioned.   The method for producing a bonded substrate according to any one of claims 2 to 13, wherein the surface of the silicon thin film is mirror-finished before and / or after the sandblasting.

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