JPH07254689A - Formation of epitaxial growth layer on insulating layer and silicon wafer having epitaxial growth layer on insulating layer - Google Patents

Abstract

PURPOSE:To obtain an SOI wafer in which the device forming layer has uniform characteristics. CONSTITUTION:A layer 4 for forming a device is grown epitaxialy on a silicon oxide 3 deposited on an SOI wafer. This structure enhances uniformity in the characteristics of epitaxial growth layer 4 as compared with a conventional wafer thus enhancing uniformity in the characteristics of device forming layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate having a layer for manufacturing a semiconductor device such as a semiconductor wafer on an insulating layer and a method for manufacturing the substrate, and more particularly to an SOI (Silicon on insulator) having silicon formed on the insulating layer. ) A wafer and its manufacturing method.

[0002]

2. Description of the Related Art FIG. 5 is a process diagram showing a method for manufacturing an SOI wafer by a conventional bonding method as shown in page 10 of Ultra Clean Technology Vo. In the figure, 1 and 2 are silicon wafers which are cut out from a normal silicon single crystal ingot and are mirror-finished, and 3 is a silicon oxide film.

Next, a method of manufacturing an SOI wafer will be described. In FIG. 5, (5-a) to (5-e) show the states of the silicon wafers 1 and 2 which have undergone the respective steps of the SOI wafer manufacturing process. According to the step (5-a), two silicon wafers 1 and 2 are prepared. Then, in accordance with step (5-b), the silicon wafer 1 is oxidized and a silicon oxide film of 1 μm is formed on the surface.
Form about m. Next, according to the step (5-c), the silicon wafer 1 and the silicon wafer 2 are bonded together. this is,
This can be done by stacking the silicon wafers 1 and 2 and performing heat treatment at 1100 ° C. for about 2 hours in a wet oxidizing atmosphere.

Then, according to the step (5-d), the silicon wafer 1 or the silicon wafer 2 on one side of the sandwiched silicon oxide film 3 is thinned to about 30 μm by surface grinding. Then, in accordance with step (5-e), the silicon wafer 1 which has been subjected to mechanochemical mirror polishing in the same manner as in the final processing step of a normal silicon wafer and surface-ground in step (5-d) is 10 μm.
The thickness is reduced to m or less.

FIG. 6 shows an apparatus for surface-polishing and mechanochemically mirror-polishing a silicon wafer 1. In FIG. 6, 1
1 is a polisher for polishing the silicon wafer 1, and 12 is a polisher.
Is two copper plates on which polisher is placed, 13 is two copper plates 12
A silicon rubber heater for heating the copper plate 12 sandwiched between the two, 14 is an asbestos plate laid below the copper plate 12, 15
Reference numeral 16 denotes a fixed substrate for supporting and rotating the polisher 11 together with the copper plate 12 or the like on the asbestos plate 14, and 16 for bonding the surface of the silicon wafer 1 in contact with the polisher 11 so that it can move up and down while holding the silicon wafer 1. A stainless plate, 18 is a guide roller for supporting the adhesive stainless plate 16, 19 is a processing agent for polishing the silicon wafer 1 at the interface between the polisher 11 and the silicon wafer 1, 20 is a panel heater, and 21 is A container for storing the processing agent 19 while being heated by the panel heater 20, 22 is a stirrer for stirring the processing agent 19 stored in the container 21, and 23 and 24 are heat generation amounts of the silicon rubber heater 13 and the panel heater 20, respectively. It is a slidac for controlling.

FIG. 7 is a plan view showing a state of the silicon wafer 1 bonded to the bonding stainless plate 16. The silicon wafer 1 is fixed with the surface to be polished facing up.

When surface grinding is performed using the apparatus shown in FIG. 6, pure water containing an abrasive is used as the processing agent 19. Also,
When performing the mechanical chemical polishing, an alkaline solution is used as the processing agent 19.

[0008]

Since the conventional SOI wafer is manufactured as described above, the uniformity of the characteristics of the silicon layer forming the device is the same as that of the silicon wafer prepared before bonding. I am taking over. In the case of a silicon wafer manufactured by a normal manufacturing method, it is impossible to eliminate so-called striations in which the characteristics change concentrically when a single crystal silicon ingot is manufactured.
Even if the I wafer is manufactured, there is a problem that the uniformity of the characteristics is poor.

The present invention has been made in order to solve the above-mentioned problems, and an SO having good characteristics uniformity is provided.
The purpose is to obtain an I-wafer, and further to provide a manufacturing method thereof.

[0010]

According to a first aspect of the present invention, there is provided a method of providing an epitaxial growth layer on an insulating layer, wherein at least one main surface is a single crystal substrate and the epitaxial growth layer is directly formed on the main surface to form an epitaxial growth layer. And a step of disposing the insulating layer on the surface of the epitaxial growth layer opposite to the surface in contact with the substrate, and a step of scraping the substrate to expose the epitaxial growth layer. ing.

The method for providing the epitaxial growth layer according to the second invention on the insulating layer is the same as the method for providing the epitaxial growth layer according to the first invention on the insulating layer. The method is characterized by including a step of forming the insulating layer on the surface and a step of forming the supporting substrate on the insulating layer so that the epitaxial growth layer and the supporting substrate face each other.

The method of providing the epitaxial growth layer according to the third aspect of the invention on the insulating layer is the method of providing the epitaxial growth layer of the first aspect of the invention on the insulating layer. The method is characterized by including a step of forming the insulating layer and a step of bonding the insulating layer on the supporting substrate and the epitaxial growth layer.

A method of providing an epitaxial growth layer according to a fourth invention on an insulating layer is the method of providing the epitaxial growth layer according to the second or third invention on the insulating layer, wherein the main surface of the substrate is a silicon single crystal. The epitaxial growth layer includes a layer in which silicon is epitaxially grown directly on the surface of the substrate,
The insulating layer includes a silicon oxide film.

A method of providing an epitaxial growth layer on an insulating layer according to a fifth aspect of the present invention comprises a step of preparing a substrate having at least one main surface made of a single crystal, and an epitaxial growth by directly performing epitaxial growth on the main surface of the substrate. Forming a layer, and implanting ions that combine with the substrate or the epitaxial growth layer to form an insulator at a predetermined depth from the surface of the epitaxial growth layer, and the ions and the substrate or the epitaxial growth layer. And a step of forming an insulating material by bonding with.

A silicon wafer having an epitaxially grown layer on an insulating layer according to a sixth aspect of the present invention is a silicon-based wafer having a support substrate having one main surface and the one main surface of the support substrate having substantially the same thickness. An insulating layer and a silicon layer formed by epitaxial growth on the entire surface of the insulating layer are provided.

[0016]

In the step of forming the epitaxial growth layer according to the first aspect of the present invention, since the epitaxial growth layer is directly grown on the main surface of the substrate having at least one main surface of the single crystal, the single crystal of the main surface of the base has It is possible to form an extremely uniform epitaxial growth layer without taking over the striation.

Then, according to the step of disposing the insulating layer,
Since the insulating layer is provided on the surface of the epitaxial growth layer opposite to the surface in contact with the substrate, the substrate can be scraped off in the next step to expose the epitaxial growth layer. In this way, even if a material that is difficult to grow epitaxially on the insulating film, if a layer made of the material can be grown epitaxially on the substrate, a layer without striation can be formed on the insulating film.

In the step of forming the insulating layer in the second invention, the insulating layer is formed on the surface of the epitaxial growth layer to form the insulating layer on the back side of the exposed surface of the epitaxial growth layer, and at the same time to form the insulating layer and the epitaxial growth layer. In the step of forming a support base by performing the bonding of step 1, the support substrate is formed on the insulating layer so that the epitaxial growth layer and the support substrate face each other, so that the substrate supporting the entire surface of the epitaxial growth layer is placed on the back side of the insulating layer. Can be formed.

In the step of forming the insulating layer in the third invention, the insulating layer is formed on the supporting substrate to form the insulating layer on the supporting substrate supporting the epitaxial growth layer,
In the bonding step, the insulating layer on the support substrate and the epitaxial growth layer are bonded together, so that the insulating layer and the support substrate can be provided on the back side of the exposed epitaxial growth layer.

The substrate in the fourth invention has a surface made of a silicon single crystal, and the epitaxial growth layer is
Since it includes a layer in which silicon is epitaxially grown directly on the surface of the substrate, an extremely uniform silicon layer can be easily obtained. Since the insulating layer includes the silicon oxide film, the insulating layer can be easily formed on the epitaxial growth layer by the same method as the conventional method.

In the step of forming the epitaxial growth layer in the fifth invention, the epitaxial growth layer is directly formed on the main surface of the substrate to form the epitaxial growth layer, so that the striations of the single crystal on the main surface of the substrate are succeeded. Without forming a very uniform epitaxial growth layer.

Then, in the step of forming the insulator, the ions that combine with the substrate or the epitaxial growth layer to form the insulator are implanted at a predetermined depth from the surface of the epitaxial growth layer, and the ions and the substrate or the epitaxial growth layer are implanted. The insulating layer can be formed in the epitaxial growth layer or in a shallow portion of the substrate by forming an insulating material by combining and.

The silicon-based insulating layer in the sixth invention is
Since the silicon wafer is formed with almost the same thickness on the entire one main surface of the supporting substrate and there is no portion in the silicon wafer that does not have an insulating layer, it is possible to distinguish any portion of the silicon layer formed by epitaxial growth on the entire insulating layer. It can be used without doing.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a process diagram showing a method for manufacturing an SOI wafer according to the first embodiment of the present invention. In FIG. 1, reference numeral 4 denotes an epitaxial growth layer formed on the silicon wafer 1, and the other portions having the same reference numerals as those shown in FIG. 5 are portions corresponding to those shown in FIG.

Next, a method for manufacturing an SOI wafer according to the present invention will be described. Those indicated by (1-a) to (1-e) are the silicon wafers 1 and 2 after the respective steps (1-a) to (1-e) of the SOI wafer manufacturing process.

First, according to step (1-a), a silicon wafer 1 having an epitaxial growth layer 4 of 0.1 μm or more is formed.
At the same time, a normal silicon wafer 2 is prepared. The epitaxial growth layer 4 may be formed thicker than a desired thickness. For example, if it is desired to finally obtain an epitaxial growth layer made of silicon having a thickness of 10 μm or less, the thickness is formed to be slightly thicker than 10 μm.

The silicon wafers 1 and 2 are ordinary silicon wafers which are cut out from a silicon single crystal ingot and whose surfaces are mirror-polished. Note that this silicon wafer may be one to which a dopant is added or an intrinsic semiconductor. For forming the epitaxial growth layer on the silicon wafer 1, for example, after exposing the silicon wafer 1 to a hydrogen atmosphere to remove the oxide film on the surface, the silicon wafer 1 is heated at 1100 ° C. in trichlorosilane SiHCl _3.
It is formed by keeping it at 1150 ° C. The thickness of the epitaxial growth layer 4 is controlled by the growth time.

Then, according to the step (1-b), the silicon wafer 1 on which the epitaxial growth layer 4 is formed is exposed to an oxygen atmosphere and oxidized to form a silicon oxide film on the surface. The thickness of the oxide film can be controlled by the time of exposure to oxygen.

Then, according to the step (1-c), the silicon wafers 1 and 2 are bonded together with the epitaxial growth layer 4 interposed therebetween. This is done by stacking the silicon wafers 1 and 2 in the same manner as in the conventional method, for example, in a wet oxidizing atmosphere at 1100 ° C.
It is possible to perform heat treatment for about an hour.

Then, according to the step (1-d), the silicon wafer 1 is thinned to about 30 μm by surface grinding from the surface opposite to the surface on which the epitaxial growth layer 4 is formed in the same manner as in the conventional case. .
Then, in accordance with the step (1-e), the epitaxially grown layer 4 is exposed by mechanochemical mirror polishing to reduce the thickness thereof to 10 μm or less, as in the conventional case. The thickness of the epitaxial growth layer 4 should be made as constant as possible in order to keep the characteristics of the device formed therein uniform. However, it is better to make the thickness as thin as possible within the range in which the transistors can be formed in the epitaxial growth layer 4, etc. Is preferable in order to improve the device characteristics. Therefore, if there is another method that can make the epitaxial growth layer thinner than mechanochemical mirror polishing, it is desirable to use that method to make the thickness uniform and thin.

The SOI wafer thus formed is
Since the characteristics of the epitaxial growth layer 4 are extremely uniform, the epitaxial growth layer 4 can be formed in the device forming layer, and it can be used as a wafer for manufacturing a miniaturized device in which the influence of striations such as ULSI is largely exhibited. Particularly suitable.

Further, the use of silicon as the material of the wafer facilitates the manufacture because the silicon oxide film 3 can be used as an insulating layer.

By forming a device on such an SOI wafer, it is possible to manufacture a device that is more resistant to latch-up, soft error, etc. than an ordinary silicon wafer, and is highly expected as a next-generation semiconductor wafer. It

Next, a second embodiment of the present invention will be described with reference to the drawings. In the above embodiment, the oxide film is formed on the silicon wafer 1 on which the epitaxial growth layer 4 is formed, but the silicon oxide film 3 may be formed on the silicon wafer 2 on which the epitaxial growth layer 4 is not formed.

FIG. 2 shows an SOI according to the second embodiment of the present invention.
It is process drawing which shows the manufacturing method of a wafer. In FIG.
The parts with the same reference numerals as those shown in FIG. 1 are the parts corresponding to those shown in FIG. A method of manufacturing an SOI wafer according to the present invention will be described. Those indicated by (2-a) to (2-e) are the respective steps (2-a) to (2-e) of the SOI wafer manufacturing process.
It is the silicon wafers 1 and 2 after passing through.

First, as in the first embodiment, according to the step (2-a), the ordinary silicon wafer 2 is prepared together with the silicon wafer 1 on which the epitaxial growth layer 4 is formed with a thickness of 0.1 μm or more. The epitaxial growth layer 4 is formed thicker than a desired thickness (for example, 10 μm or more).

Then, according to step (2-b), the silicon wafer 2 is exposed to an oxygen atmosphere and oxidized to form a silicon oxide film on the surface. The thickness of the oxide film is controlled by the time of exposure to oxygen.

Then, according to the step (2-c), the silicon wafers 1 and 2 are bonded together with the epitaxial growth layer 4 interposed therebetween. This is similar to the first embodiment in that the silicon wafer 1,
2 in layers, for example, in a wet oxidizing atmosphere, 110
It is possible to perform the heat treatment at 0 ° C. for about 2 hours.

Then, according to the step (2-d), the silicon wafer 1 is thinned to about 30 μm by performing surface grinding from the surface opposite to the surface on which the epitaxial growth layer 4 is formed, as in the conventional case. .
Then, in accordance with the step (2-e), the epitaxial growth layer 4 is exposed by mechanochemical mechanical polishing to expose the epitaxial growth layer 4 and the thickness thereof is reduced to 10 μm or less as in the conventional case.

The SOI wafer thus formed is
Similar to the first embodiment, since the epitaxial growth layer 4 has extremely good uniformity of characteristics, it is particularly suitable for a wafer used for manufacturing a miniaturized device in which the influence of striation, such as ULSI, is large. The use of silicon as the material facilitates the manufacture.

In the above embodiment, the silicon wafer 2
Was used as the supporting substrate for the epitaxial growth layer 4 formed on the silicon oxide film 3, but since the silicon oxide film 3 acts as an insulator, another insulator, semiconductor, or conductive material can be used without using the silicon wafer 2. A carrier may be used, and such a material can be used as long as it has heat resistance of about one thousand and several hundred degrees Celsius as a heat resistant temperature in a state of being bonded to the silicon oxide film 3.

Further, in the above embodiment, the silicon wafer 1 is used to form the epitaxial growth layer 4. This is selected because it is easy to obtain a particularly uniform epitaxial growth layer by epitaxially growing silicon on single crystal silicon. However, a material other than silicon may be used as long as a uniform epitaxial growth layer can be formed and removed without damaging the epitaxial growth layer. For example, a material such as a compound semiconductor or germanium may be used as the material for the silicon wafer 1 and the epitaxial growth layer 4.

Although the silicon oxide film 3 is used as the insulating layer in the above embodiment, another insulating film may be used.
For example, a silicon nitride film obtained by nitriding the epitaxial growth layer 4 made of silicon may be used, and other insulating materials may be used as long as they can be bonded well and have the necessary heat resistance. Oxidation was used as the method for forming the insulating layer, but an insulating material such as a silicon oxide film or a silicon nitride film may be deposited, and the same effect as that of the above-described embodiment can be obtained.

Next, a third embodiment of the present invention will be described with reference to the drawings. In the above first and second embodiments, the case of manufacturing the SOI substrate by the bonding method is shown, but the manufacturing method may be performed by other methods. For example, a manufacturing method using the implantation of oxygen ions is shown in FIGS. 3 and 4
In FIG. 1, 5 is an oxygen ion implanted in the epitaxial growth layer 4 made of silicon by the ion implantation method, 6 is a buried oxide film formed on the epitaxial growth layer made of silicon by the ion implantation method.
The parts designated by the same reference numerals as those shown in FIG. 1 are the parts corresponding to those shown in FIG.

As shown in FIG. 3, a silicon wafer 1 on which an epitaxially grown layer 4 is formed is prepared on the epitaxially grown silicon wafer 1 according to the step (3-a) as in the first embodiment. Oxygen is applied to the epitaxially grown silicon wafer 1 in the range of 180 to 200 ke according to the process (3-b).
Ion implantation is performed at about v. Then 1300-1320 ° C
By heat-treating for about 6 hours in the argon / oxygen atmosphere, the oxygen ions 5 and silicon are combined to form an insulating layer made of silicon oxide. Thus, the SO having the silicon oxide layer 6 in the middle of the epitaxial growth layer 4
I substrate can be manufactured.

Since the epitaxial growth is directly carried out on the surface of the single crystal silicon wafer 1, an extremely uniform epitaxial growth layer 4 made of silicon can be obtained. In other words, it is possible to eliminate the striation in which the concentration of impurities contained in the silicon wafer 1 varies depending on the place. Therefore, it has the same effect as the first and second embodiments. By the way, when the silicon wafer 1 is first ion-implanted, the surface of the silicon wafer 1 is roughened.
Not suitable for uniform epitaxial growth.

As shown in FIG. 4, oxygen ions 5 may be implanted deeper than the thickness of the epitaxial growth layer 4 to bond the oxygen ions 5 and the silicon wafer 1 to form a silicon oxide film.

The ions to be implanted may be other than oxygen ions, as long as they react with the epitaxial growth layer 4 or the wafer to form an insulator, and the same effect as in the above-mentioned embodiment is obtained.

Further, the materials for the wafer and the epitaxial growth layer are not limited to silicon, and any material capable of forming an insulator by being combined with implanted ions can be obtained, and the same effects as those of the above-mentioned embodiment can be obtained.

[0050]

As described above, according to the method of providing the epitaxial growth layer of the present invention on the insulating layer,
The epitaxial growth layer is formed by directly epitaxially growing on the main surface of the single crystal, the insulating layer is provided on the surface of the epitaxial growth layer, and the substrate is scraped off to expose the epitaxial growth layer, so that an extremely uniform layer is formed on the insulating layer. The effect is that it can be formed.

According to the method of providing the epitaxial growth layer on the insulating layer according to the second aspect of the present invention, the insulating layer is formed on the surface of the epitaxial growth layer and the insulating layer is formed on the insulating layer so that the epitaxial growth layer and the supporting substrate face each other. Since the support substrate is formed, there is an effect that the support substrate supporting the epitaxial growth layer can be formed further below the insulating layer formed under the extremely uniform epitaxial growth layer.

According to the third aspect of the present invention, in which the epitaxial growth layer is provided on the insulating layer, the insulating layer is formed on the supporting substrate, and the insulating layer on the supporting substrate and the epitaxial growing layer are bonded together. There is an effect that a supporting substrate that supports them can be formed below the insulating layer formed under the uniform epitaxial growth layer.

According to the method of providing the epitaxially grown layer on the insulating layer according to the fourth aspect of the present invention, the main surface of the substrate includes a surface made of silicon single crystal, and the epitaxially grown layer directly deposits silicon on the surface of the substrate. Since the insulating layer includes the epitaxially grown layer, and the insulating layer includes the silicon oxide film, the insulating layer can be easily formed below the silicon-based insulating layer formed under the epitaxially grown layer made of extremely uniform silicon.
There is an effect that the formation of a silicon substrate that supports them can be realized.

According to the method of providing the epitaxial growth layer on the insulating layer according to the fifth aspect of the present invention, the epitaxial growth layer is formed by directly performing epitaxial growth on the main surface of the substrate made of a single crystal, and is bonded to the substrate or the epitaxial growth layer. Ions that form an insulator are implanted at a predetermined depth from the surface of the epitaxial growth layer, and the ions are combined with the substrate or the epitaxial growth layer to form an insulator. The effect is that it can be formed on top.

According to the silicon wafer having the epitaxial growth layer of the present invention on the insulating layer, the silicon-based insulating layer formed to have substantially the same thickness on the entire one main surface of the support substrate and the entire surface of the insulating layer. Since it is provided with a silicon layer formed thereon by epitaxial growth, there is an effect that the uniformity of the characteristics of the layer in which the device is formed can be greatly improved without lowering the yield of the device.

[Brief description of drawings]

FIG. 1 is a flow chart showing a manufacturing process of an SOI wafer according to a first embodiment of the present invention.

FIG. 2 is a flow chart showing an SOI wafer manufacturing process according to a second embodiment of the present invention.

FIG. 3 is a flow chart showing a manufacturing process of an SOI wafer according to a third embodiment of the present invention.

FIG. 4 is a flowchart showing manufacturing steps of an SOI wafer according to a fourth embodiment of the present invention.

FIG. 5 is a flowchart showing a conventional SOI wafer manufacturing process.

FIG. 6 is a view showing an apparatus used for manufacturing a conventional SOI wafer.

FIG. 7 is a diagram for explaining an apparatus used for manufacturing a conventional SOI wafer.

[Explanation of symbols]

 1, 2 Silicon wafer 3 Silicon oxide film 4 Epitaxial growth layer 5 Oxygen ion 6 Silicon oxide layer

Claims (6)

[Claims] 1. A step of forming an epitaxial growth layer by directly epitaxially growing on at least one main surface of a single-crystal substrate, the surface of the epitaxial growth layer opposite to the surface in contact with the substrate. A method of providing an epitaxial growth layer on an insulating layer, the method comprising: disposing an insulating layer on the insulating layer; and scraping the substrate to expose the epitaxial growth layer. 2. The step of disposing the insulating layer, the step of forming the insulating layer on the surface of the epitaxial growth layer, and the support on the insulating layer so that the epitaxial growth layer and a support substrate face each other. Forming a substrate on the insulating layer. 3. The step of disposing the insulating layer includes the step of forming the insulating layer on a supporting substrate, and the step of adhering the insulating layer on the supporting substrate to the epitaxial growth layer. Item 2. A method for providing an epitaxial growth layer according to item 1 on an insulating layer. 4. The main surface of the base includes a surface made of silicon single crystal, the epitaxial growth layer includes a layer in which silicon is directly epitaxially grown on the surface of the base, and the insulating layer is made of silicon oxide. A method for providing an epitaxial growth layer according to claim 1 or 2 on an insulating layer, the method comprising a film. 5. A step of preparing a substrate having at least one main surface made of a single crystal, a step of directly epitaxially growing on the main surface of the substrate to form an epitaxial growth layer, and bonding to the substrate or the epitaxial growth layer. Implanting ions to form an insulator at a predetermined depth from the surface of the epitaxial growth layer, and combining the ions with the substrate or the epitaxial growth layer to form an insulator. A method of providing an epitaxial growth layer on an insulating layer. 6. A support substrate having one main surface, a silicon-based insulating layer formed on the entire one main surface of the support substrate with substantially the same thickness, and formed on the entire surface of the insulating layer by epitaxial growth. A silicon wafer having an epitaxially grown layer on an insulating layer, the silicon wafer including a silicon layer.