JP2003203899A - Method and device for manufacturing epitaxial wafer silicon single-crystal substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To selectively remove a blocking film of the chamfered part of a substrate, without causing unevenness in the form of the blocking film on the back of an epitaxial wafer silicon single-crystal substrate for restricting a production of a nodule in the chamfered part when an epitaxial layer is growth, and further to efficiently and accurately remove the blocking film of this chamfered part with high productivity. <P>SOLUTION: This method comprises a step of exposing each chamfered part of one or a plurality of substrates to be laminated by pinching a thin plate having the almost same shape as the substrate, and a step of updating an etching agent and simultaneously bringing into contact with the substantially entire surface of the exposed chamfering part. Thus, a blocking film of the chamfering part is selectively removed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing a silicon single crystal substrate for an epitaxial wafer.

[0002]

2. Description of the Related Art An epitaxial film manufactured by reacting a gaseous raw material on the outer surface of a silicon single crystal substrate (hereinafter, simply referred to as a substrate) to form a thin layer of silicon single crystal (hereinafter, referred to as an epitaxial layer) on the substrate. The wafer has a steeper profile compared to the concentration profile of the dopant element (hereinafter referred to simply as the dopant) formed on the surface layer of the substrate by the thermal diffusion method. Oxygen and other impurities are contained in the epitaxial layer. Is extremely small, and since a high resistance (high electric resistance value) epitaxial layer can be formed on a low resistance (low electric resistance value) substrate, collector resistance can be made low in bipolar devices. It is possible to increase the breakdown voltage between the collector and substrate while maintaining it, and suppress latch-up in CMOS devices. Be such, it is a very useful material to increased density and characteristics of the silicon semiconductor element.

Now, the production of such an epitaxial wafer is carried out by so-called CVD (Chemical Vapor Deposition).
Carried out by law. That is, while maintaining the substrate placed in the reactor at a predetermined temperature, a gas of a raw material silicon compound (chlorosilanes such as silane and trichlorosilane) is sent together with a carrier gas (usually hydrogen gas),
An epitaxial layer is grown by reacting on the outer surface of the substrate.
If desired, when a desired amount of a predetermined dopant is added to the epitaxial layer, a gas of the compound of the dopant is simultaneously fed while controlling the amount thereof.

In the process of growing the epitaxial layer, a part of the dopant previously added to the substrate escapes from the substrate into the vapor phase to change the composition of the vapor phase, whereby the dopant in the epitaxial layer is changed. A so-called autodoping phenomenon occurs that the concentration is changed or the steepness of the dopant concentration profile is lost. As one of the measures to suppress this undesirable phenomenon, a method of forming a thin film of silicon oxide or the like on the surface of the substrate to prevent the dopant in the substrate from escaping into the gas phase is used. (A thin film for this purpose is hereinafter referred to as a blocking film.) Silicon oxide is most often used as this blocking film. To form it, the substrate is heated in a gas phase containing oxygen. The method of directly oxidizing silicon, the method of depositing a silicon oxide film (hereinafter referred to as an oxide film) on the outer surface of the substrate by the CVD method, and the like are used. The oxide film on the main outer surface (hereinafter referred to as the main surface) of the substrate on which the epitaxial layer is grown is then removed by a method such as polishing. The cross section perpendicular to the main surface of the silicon single crystal substrate for an epitaxial wafer manufactured in this manner has a structure schematically shown as 1 in FIG. In addition to the outer surface (hereinafter referred to as the back surface), the blocking film 2 also exists on the surface of the so-called chamfered portion provided on the peripheral portion of the substrate.

However, when a blocking film is present in the chamfered portion, a polycrystalline silicon precipitate called nodule is formed on the surface of the blocking film in the chamfered portion in the process of growing the epitaxial layer. These nodules are peeled off during the subsequent process of handling the epitaxial wafer or in the course of transportation, which causes so-called particle trouble, which causes deterioration of product quality and reduction of yield.

In order to prevent the particle trouble due to the nodules, it is effective to remove the blocking film at the chamfered portion that causes nodule formation, and some methods have been proposed so far. . For example, in JP-A-62-128520,
As shown in FIG. 6, the substrate 1 having the blocking film 2
While rotating the head, the head 62 is formed on the surface of the portion 3 of the blocking film including the chamfer to be removed (hereinafter, the portion 3 including the chamfer where the blocking film is to be removed is simply referred to as a peripheral surface). A non-woven fabric 61 which is built in the substrate and is pressed with an etching solution to remove only the blocking film on the peripheral edge treated surface 3, or as shown in FIG. There is proposed a method of moving it so as to physically remove it.

Further, Japanese Laid-Open Patent Publication No. 10-70080 discloses a method of removing only the CVD oxide film on the side surface of the main surface of the substrate by a tape polishing method.

Further, in Japanese Patent Application Laid-Open No. 7-226349, a plurality of substrates having a blocking film formed thereon are closely attached to a flat plate-like packing having a substantially equal diameter and annular steps at the peripheral portions of both surfaces. So as to form a laminated body, and the laminated body is immersed in an etching solution,
A method is disclosed in which only the blocking film on the exposed portion of the packing is not adhered and is removed.

However, according to the method of the above-mentioned Japanese Patent Laid-Open No. 62-128520, since the contact condition of the nonwoven fabric is not uniform in the entire area of the peripheral treated surface, the removal of the blocking film does not proceed uniformly, and the blocking film to be left behind. It has been found that there is a drawback in that the periphery of is not a smooth circle. Further, in the method using the polishing grindstone, the position of the boundary between the area to be removed and the area to be removed of the blocking film varies depending on the condition of the polishing grindstone, and the surface of the substrate where the polishing grindstone is pressed is changed. There was a problem that processing strain remained.

In the method disclosed in Japanese Patent Laid-Open No. 10-70080, it is possible to avoid the above problems, but the productivity is poor because the substrates are processed one by one.

According to the method disclosed in Japanese Patent Laid-Open No. 7-226349, a plurality of substrates can be processed at the same time.
Although the effect of improving productivity is recognized, it has become clear that the following problems occur. That is, it is difficult to keep the degree of adhesion between the main outer surface of the wafer and the main outer surface of the packing uniform over the entire area in which they contact each other, and the etching solution is not sufficiently adhered to the peripheral portion during etching. Penetration between the substrate and the packing can cause unwanted removal of the blocking film.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the conventional method, and suppresses the generation of nodules in the method of manufacturing a silicon single crystal substrate for an epitaxial wafer. Therefore, the present invention provides a method capable of selectively and uniformly removing only the blocking film on the peripheral treated surface, and an apparatus therefor. Another object of the present invention is to provide a method and an apparatus capable of performing this treatment extremely efficiently in terms of productivity and cost.

[0013]

As in the prior art, when the outline of the blocking film covering the back surface of the substrate is not mean circular but meandering, the degree of auto-doping phenomenon is high. The concentration of the dopant in the epitaxial layer, which varies from place to place at the periphery,
Or, the profile in the vicinity of the interface between the epitaxial layer and the substrate becomes non-uniform over the entire area of the epitaxial wafer, resulting in an unfavorable result for product quality. In order to solve this problem, it is indispensable to remove the blocking film on the peripherally treated surface so that the shape of the blocking film on the back surface becomes a uniform circular shape without meandering. And then devised a useful method and device for it.

That is, the substrate is sandwiched between the thin plates so that only the peripheral processing surface is exposed, and the etching solution uniformly contacts the entire exposed portion (hereinafter, simply referred to as an exposed portion) to react with the blocking film, and to react. We devised a method for removing products rapidly and a device therefor. In addition, we devised an effective method of bringing the etching liquid into close contact with the substrate and the thin plate so that they do not penetrate into the overlapping portion.

Further, in order to process a plurality of substrates at the same time to enhance the productivity of the process, a method of processing substrates and thin plates alternately and processing them as a laminated body, and an apparatus therefor have been devised.

As described above, one of the major features of the present invention is a contact method in which the etching solution does not penetrate between the substrate and the thin plate. Another feature is a method capable of uniformly contacting the entire area of the peripherally treated surface with an etching solution to react with the blocking film on the peripherally treated surface and quickly removing the reaction product. Is a device capable of carrying out.

The features of the present invention will be described below with reference to the claims.

The method for producing a silicon single crystal substrate for an epitaxial wafer according to the present invention is such that one or a plurality of silicon single crystal substrates each having a thin film formed on the outer surface thereof is exposed at least at a portion including a chamfered portion thereof. A thin plate having the same shape is sandwiched to form a laminated body, and the etching solution is renewedly contacted with substantially the entire surface of the exposed portion of the substrate to selectively remove only the thin film on the surface of the exposed portion of the substrate. To do.

One of the methods for manufacturing a silicon single crystal substrate for an epitaxial wafer according to the present invention is one in which a thin film is formed on the outer surface of a substrate or a plurality of substrates, and at least a portion including a chamfered portion thereof is exposed so that the substrate is almost the same as the substrate. A step of sandwiching the thin plates of the same shape into a laminated body, and immersing the laminated body in an agitating etchant, or etching the laminated body around an axis perpendicular to the main outer surface of the substrate. At least one of the step of immersing in the solution or the step of immersing the laminate in an agitating etching solution while rotating the laminate around an axis perpendicular to the main outer surface of the substrate is selected. It is characterized in that the etching solution is brought into contact with substantially the entire surface of the exposed portion of the substrate while being renewed to selectively remove only the thin film on the surface of the exposed portion of the substrate.

In the method for producing a silicon single crystal substrate for an epitaxial wafer according to the present invention, one or a plurality of silicon single crystal substrates having a thin film formed on the outer surface is exposed by exposing at least a portion including the chamfered portion. It is sandwiched by thin plates of almost the same shape as the above, and the etching liquid is renewed over substantially the entire surface of the exposed portion of the substrate by using a brush while rotating the laminated body around an axis perpendicular to the main outer surface of the substrate. While contacting, the thin film on the surface of the exposed portion of the substrate is selectively removed.

In the conventional method of immersing the laminate in the etching solution to remove the blocking film on the peripherally treated surface, even when the laminate is formed by the method according to the above-mentioned patent, the laminate is locally exposed on the exposed portion of the substrate. As a result of the bubbles adhering and the contact of the etching liquid with the blocking film being blocked at that location, another problem occurs in that the blocking film at that location is not sufficiently removed. In the method of the present invention, the adherence of air bubbles is ensured by making sure that the etching liquid is brought into contact with substantially the entire exposed portion of each substrate formed as a laminate and constantly updating the etching liquid that comes into contact with the surface of the exposed portion. Can be prevented.

The method of the present invention is also useful when treating substrates one by one, but from the viewpoint of productivity, it is possible to treat a plurality of substrates at the same time, and it is particularly effective at that time.

The thin plates sandwiching the substrate are not particularly limited as long as they have corrosion resistance to the etching solution.

In particular, in the method using a brush, the etching liquid is sufficiently supplied to the gap between the substrate and the thin plate by the tip of the brush of the brush, and the etching liquid can be more surely brought into contact with the entire exposed area of the substrate. . Furthermore, since the reaction product can be mechanically removed by the tip of the brush of the brush, it is further effective.

The method of the present invention is characterized in that the brush is rotated or swung in the same or opposite direction to the rotating direction of the laminate.

That is, by rotating or oscillating the brush in this manner, the action of more surely bringing the etching liquid into contact with the entire exposed portion of the substrate substantially evenly and mechanically removing the reaction product. Can be exhibited more effectively.

In this case, the rotating direction of the brush and the rotating direction of the laminated body may be either the same direction or opposite directions, but the opposite direction is more effective because the mechanical action is stronger.

Further, the method using a brush can achieve the object with a small amount of etching solution as compared with other methods.

The method of the present invention is characterized in that water is interposed between the substrate and the thin plates when the substrates and the thin plates having substantially the same shape are alternately superposed and laminated.

That is, when water is interposed between the substrate and the thin plate, the water and the substrate or the water and the thin plate can be brought into close contact with each other by an adhesive force.

Further, since the etching solution can be prevented from penetrating between the two, the problem of the conventional method in which the blocking film is unnecessarily removed can be effectively solved.

Further, according to the method of the present invention, when pressure is applied in a direction perpendicular to the main outer surface of the substrate or the thin plate to form a laminate of the substrate and the thin plate, pressure is applied to at least the peripheral portion of the substrate or the thin plate. It is characterized by

As described above, it is more effective to form the laminated body by applying pressure so as to improve the adhesion between the substrate and the thin plate and prevent the etching solution from penetrating between them.

The method of the present invention is characterized by using a thin plate which has substantially the same shape as the substrate and whose peripheral edge is chamfered.

The method of the present invention is also characterized in that a thin plate having substantially the same shape as that of the thin film to be left without being removed is used.

That is, in the present invention, since the thin plate is chamfered at the peripheral edge like the substrate, the tips of the brush reach the corners of the exposed portion, and the etching liquid is evenly contacted over almost the entire peripheral processed surface. Etching is performed. Moreover, the reaction products are forced out of the peripheral treated surface by the brush. Similarly, when a thin plate having the same shape as the blocking film to be left on the back surface is used, the bristle tips contact almost the entire peripheral surface of the substrate, so that only the peripheral surface is reliably etched.

The step of producing a silicon single crystal substrate for an epitaxial wafer is constructed so that the blocking film on the peripheral surface is removed by the method of the present invention and then the blocking film on the main surface of the substrate is removed. Or
There is no particular limitation even if the blocking film on the peripheral treatment surface is removed by the method of the present invention after removing the blocking film on the main surface, but the latter configuration is easier to handle in later steps. It is more desirable because the peripheral edge is less likely to be chipped.

The method of the present invention is characterized in that the thin film formed on the outer surface of the substrate is an oxide of silicon.

That is, the thin film formed on the outer surface of the substrate is not particularly limited as long as it is a material that functions as a blocking film for suppressing the above-mentioned autodoping phenomenon. However, when the substrate is a silicon single crystal, silicon oxide is most preferable. It is convenient.

The method of the present invention is characterized in that the etching solution is hydrofluoric acid.

That is, hydrofluoric acid is effective as the etching solution, and is particularly excellent when the blocking film is an oxide.

The apparatus for producing a silicon single crystal substrate for an epitaxial wafer according to the present invention comprises one or a plurality of silicon single crystal substrates having a thin film formed on the outer surface thereof so that at least a portion including the chamfered portion is exposed. A laminated body is formed by sandwiching the thin plates having substantially the same shape, and the etching solution is renewedly contacted with substantially the entire surface of the exposed portion of the substrate to selectively remove only the thin film on the surface of the exposed portion of the substrate. It is characterized in that it is configured as follows.

The apparatus for producing a silicon single crystal substrate for an epitaxial wafer according to the present invention also includes one or a plurality of silicon single crystal substrates having a thin film formed on the outer surface thereof so that at least a portion including the chamfered portion is exposed. And a stacking portion that forms a laminated body by sandwiching it with thin plates having substantially the same shape, and an etching portion that etches by contacting the thin film of the substrate exposed portion of the laminated body with the etching liquid constantly over substantially the entire surface thereof, The invention is characterized in that an unstacking portion for decomposing the etched laminated body into a substrate and a thin plate is provided, and only the thin film on the surface of the exposed portion of the substrate is selectively removed.

Further, in the apparatus for manufacturing a silicon single crystal substrate for an epitaxial wafer according to the present invention, the stacking portion allows a water film to be formed between the substrate and the thin plate so that the substrate can be sandwiched between the thin plates. It is characterized by having means.

Furthermore, in the apparatus for manufacturing a silicon single crystal substrate for an epitaxial wafer according to the present invention, the etching section applies pressure in a direction perpendicular to the main outer surface of the substrate at least at the peripheral portion of the substrate to sandwich the substrate between the thin plates. It is characterized by having a laminated body pressure holding mechanism.

In the apparatus for manufacturing a silicon single crystal substrate for an epitaxial wafer according to the present invention, the substrate is a thin plate so that the etching unit matches the center of the main outer surface of the substrate with the center axis of the substrate perpendicular to the main outer surface. A means for freely rotating the laminated body sandwiched and sandwiched around its central axis, a means for freely rotating the brush-implanted rod-shaped brush around the central axis, and a central axis for each of the laminated body and the rod-shaped brush. The surface of the exposed part of the substrate is substantially It is characterized in that the brush of the rod-shaped brush rubs against the entire surface.

The apparatus for producing a silicon single crystal substrate for an epitaxial wafer of the present invention comprises means for controlling at least one of the temperature and the supply amount of the etching solution, or a means for simultaneously controlling the temperature and the supply amount of the etching solution. It is characterized by

That is, in order to stably and uniformly remove the blocking film from the peripheral treated surface for each processing batch,
In addition to controlling the characteristics of the etching solution such as the composition, it is effective to control the temperature or the supply amount to a desired value. Furthermore, the effect of increasing the use efficiency of the etching liquid is great.

The apparatus for producing a silicon single crystal substrate for an epitaxial wafer according to the present invention is characterized by including a cleaning liquid supply means for cleaning the laminated body or a portion other than the laminated body.

Further, the apparatus for producing a silicon single crystal substrate for an epitaxial wafer of the present invention comprises means for controlling at least one of the temperature and the supply amount of the cleaning liquid, or a means for simultaneously controlling the temperature and the supply amount of the cleaning liquid. It is characterized by

That is, by controlling the temperature of the cleaning liquid, the cleaning can be carried out more effectively and the treatment can be carried out stably for each batch. Further, by controlling the supply amount of the cleaning liquid, it is possible to eliminate the waste of the cleaning liquid for each batch and perform the cleaning most efficiently in terms of cost.

An apparatus for producing a silicon single crystal substrate for an epitaxial wafer according to the present invention is provided with a mechanism for rotating a laminated body,
By individually operating the mechanism that rotates the rod brush or the mechanism that changes the distance between the substrate and the brush, the rotation direction and rotation speed of the substrate, the rotation direction and rotation speed of the brush, or the distance between the substrate and the brush. It is characterized in that it is provided with means for controlling each.

That is, by controlling each of these mechanisms, each function of the apparatus can be independently and accurately realized under the most desirable conditions, so that the stability of the quality or the productivity can be improved throughout the batch of each process. In terms of surface, it is possible to exert a very high effect.

In the apparatus for manufacturing a silicon single crystal substrate for an epitaxial wafer according to the present invention, the stacking portion has a substrate stocking means, a thin plate stocking means, a substrate removing means, a thin plate taking out means, a substrate stage, a thin plate stage, a substrate carrying means, a thin plate carrying means. , A water film forming means and a stacking stage are provided, the thin plate is taken out from the thin plate stocking means by the thin plate taking-out means and conveyed onto the thin plate stage, and the thin plate center axis is placed so as to match the thin plate stage central axis, After being positioned by, the thin plate is transferred to the stacking stage by the thin plate conveying means, and the thin plate is placed on the pressing jig placed on the stacking stage so that the central axis of the thin plate coincides with the central axis of the stacking stage. To form a water film on the upper surface of the thin plate, and then
The substrate is taken out from the substrate stocking means by the substrate taking-out means, is transferred onto the substrate stage, is placed so that the central axis of the substrate coincides with the central axis of the substrate stage, is positioned on the substrate stage, and then the stacking stage is caused by the substrate carrying means. Then, the substrate is placed on a thin plate placed on the stacking stage so that the central axis of the substrate coincides with the central axis of the stacking stage, and a water film is formed on the upper surface of the substrate by the water film forming means, and then, A second thin plate is placed on the first substrate in the same manner as described above to form a water film, and thereafter, similarly, the substrates and the thin plates are alternately stacked on the stacking stage to place a predetermined number of substrates. It is characterized in that it is configured such that the laminate is placed, and finally the thin plate is placed to form a laminated body.

Although the features of the present invention and the effects obtained by them have been described above, as is further known from the description of the embodiments, the method and apparatus of the present invention can provide a large number of substrates at one time as compared with the conventional method. Can be treated, the productivity of the treatment process is significantly increased.

[0056]

Embodiments of the present invention will be described in detail below with reference to the drawings, but the present invention is not limited to these and can be carried out within the scope of the technical idea of the present invention. It includes all aspects. For example, in the device in the actual rotation example, the laminated body is entirely configured to rotate about the vertical rotation axis, but naturally it may be configured to rotate about the horizontal rotation axis. It is possible.

(Comparative Example) FIG. 5 is a schematic view showing a conventional method in which a substrate is sandwiched between thin plates to form a laminated body and a blocking film on a peripheral surface is removed by etching. Substrate 1 (diameter: 8 inches, thickness: 735) from which the oxide film on the main surface is removed
μm, oxide film thickness: 5000 Å) 6
A thin polyvinyl chloride resin thin plate (hereinafter referred to as a spacer in the examples) 51 (diameter: 200 mm, thickness: 0)
Both are alternately stacked so as to be sandwiched between 0.5 mm, without chamfering, and tightening jig 52 (material: polyvinyl chloride resin, external dimensions: width 260 mm, depth: 260 m).
m, total height: 350 to 360 mm), and the laminate 11 was assembled by tightening.

The laminated body 11 was formed into an etching bath 54 (made of polyvinyl chloride resin, internal dimensions: width 300 mm × depth 300).
mm hydrofluoric acid 53 (concentration: 2)
0%, temperature: approx. 23 ° C) Immerse in about 15 liters,
The oxide film on the peripheral processed surface of the substrate was removed by performing a process for 15 minutes while occasionally shaking manually. Immediately after the treatment, the laminate was washed with pure water (electrical conductivity: 0.1 micro mhos or less, particles: 0.1 micron or more, 100 pieces / ml or less) (not shown) (made of polyvinyl chloride resin). , Inner dimensions: width 350 mm x depth 320 mm x height 230 mm)
The plate was sequentially dipped in three tanks to wash off the etching solution and then dried. When the shape of the residual oxide film on the back surface of the substrate was adjusted, it was found that three of the 60 substrates had residual air bubbles on the peripheral edge of the residual oxide film and the substrate and the thin plate as schematically shown in FIG. An unreacted portion (B), which is considered to be caused by extra water seepage, and a defect portion (A) of the oxide film due to penetration of the etching solution were observed.

(Embodiment of the Invention) FIG. 9 is a flow chart showing an example of a process using the method or apparatus of the present invention. In FIG. 9, a thin plate and a substrate satisfying the requirements of the present invention are alternately stacked in the stacking portion of the present invention to form a laminate, and the oxide film on the peripheral processing surface of the substrate is removed by the etching portion of the present invention. In the unstacking part of the invention, the laminate is separated into a substrate and a thin plate. The recovered substrate is transferred to the drying unit and dried. A silicon single crystal substrate for an epitaxial wafer is manufactured through these steps. Examples will be described in detail below for each of the main steps of the present invention.

FIG. 1 is a schematic view showing an example of an etching part which is one of the main steps of the present invention. 160 sheets of the same substrate as in the comparative example were exposed by exposing the chamfered portion of the substrate, and a spacer made of a hard polyvinyl chloride resin (diameter: 198 mm, thickness:
0.8 mm, without chamfering) to form a laminated body 11 alternately, and the laminated body 11 is rotated through the pressing jigs 34, 34 'as illustrated in FIG. A pressure spindle 33 was used to apply a load of approximately 1.2 MPa between the laminate holders 32 and 32 ′ arranged to be rotated by means (not shown). While rotating the laminated body 11 by the laminated body rotating shaft at 5 times per minute, the brush 16 shown in FIG. 1 (external dimensions: diameter 90 m
m × length 280 mm, material of hair: polypropylene, dimension of hair: diameter 0.1 mm × length 20 mm, planting density: about 2
00 pieces / cm ² ) is rotated at a rate of 35 times per minute in the direction opposite to the rotation direction of the laminated body 11. Hydrofluoric acid (concentration: 20%) kept at a temperature of about 22 ° C. is caused to flow through the etching solution supply pipe 13, and the bristles 17 of the brush 16 are sprayed from a plurality of pores 15 provided in the etching solution supply pipe 13. The brush 16 is moved to a position where the tip of the bristles 17 of the brush is sufficiently eroded over the entire exposed portion of the substrate by a brush moving mechanism (not shown).
Was moved to remove the oxide film on the peripheral surface. The amount of hydrofluoric acid supplied to the brush was 1,000 ml / min. When the treatment time of 30 seconds has elapsed, the supply of hydrofluoric acid is stopped, and the brush 16 is supplied from the cleaning liquid supply pipe (not shown).
2, deionized water (electrical conductivity of 0.1 micro mhos or less, particles: 0.1 micron or more and 100 pieces / ml or less)
While spraying at a rate of 000 ml / min, 5,000 at the same time
The laminate 11 was washed by pouring it directly onto the laminate 11 at a rate of 0 ml / min. The brush 16 was moved away from the laminated body 11 by the brush moving mechanism to further wash the laminated body 11.
The brush rotating shaft and the laminated body rotating shaft were stopped, the laminated body 11 was removed from the apparatus, the laminated body 11 was disassembled, and the substrate was taken out. After the substrate was dried, the shape of the residual oxide film on the back surface of the substrate was examined, and it was found that the shape of the peripheral portion was a uniform circular shape.

FIG. 2 shows the process of assembling the laminate of the present invention.
It is a figure which shows each shape and dimension of a board | substrate and a spacer. The blocking film 2 exists on the back surface and the chamfered portion of the substrate 1. In the embodiment schematically shown in FIG. 2 (A), since the spacer 21 is chamfered at the peripheral edge similarly to the substrate,
The bristles of the brush reach the corners of the exposed portion, and the etching liquid is uniformly contacted with almost the entire area of the peripheral surface to be etched. Moreover, the reaction products are forced out of the peripheral treated surface by the brush. Water is interposed between each of the contact surfaces of the substrate 1 and the spacer 21, as described later,
The adhesive force between water and the substrate or water and the spacer enhances the adhesion between the substrate and the spacer. In the embodiment shown in FIG. 2B, the stacked body is formed by using the spacer 22 having the same shape as the blocking film left on the back surface. In this case as well, as in the case of FIG. 2A, since the bristle tips of the brush come into contact with almost the entire peripheral edge processing surface of the substrate, only the peripheral edge processing surface is surely etched. In this case as well, it is desirable to interpose a thin layer of water in the contact portion between the substrate 1 and the spacer 22. As a result, the adhesion between the substrate 1 and the spacer 22 is improved, and the etchant is effectively prevented from penetrating between them.

An example of a so-called "water-bonding" method in which water is interposed between the substrate and the spacer to bring them into close contact, that is, an example of a water film forming means will be described with reference to FIG. In this example,
Reference numeral 41 is an annular porous body having an outer diameter substantially equal to the diameter of the substrate. Water is supplied to and contained in the porous body 41 through the pipe 42, and the porous body 41 is brought into contact with the upper surface of the substrate 1 so that the central axis of the substrate and the central axis of the porous body 41 coincide with each other to form a water film. It is formed on the peripheral portion of the substrate. The water film forming means can be devised so that it also has a function of holding the substrate or the spacer.

The other water film forming means is constituted so that water is sprayed on the spacer stacked on the stacking stage or the upper surface of the substrate.

FIG. 8 conceptually shows an example of a stacking device devised for stacking a substrate and a spacer. In this figure, 81 is a stacking stage,
The top end of the columnar support is fitted with a countersunk pressure jig 32 '. A pressing jig 34 'is fitted on the pressure jig 32', and the spacer 2 is sequentially placed on the pressing jig 34 '.
1 and the substrate 1 are alternately stacked to form a laminated body. The spacer 21 is taken out from the spacer cassette (not shown) by the thin plate taking-out robot 84 and placed on the thin plate stage 82. This thin plate stage 82 is provided with a thin plate positioning mechanism, and by using this mechanism,
The spacer is positioned so that the center axis of the spacer and the notch or flat portion (corresponding to the orientation flat of the substrate) provided on the peripheral edge of the spacer have a predetermined positional relationship with the holding surface of the thin plate transport robot 86. Then, the thin plate transport robot 86 is operated to hold the spacers in the thin plate holder, and the stacking stage 81
It is conveyed so as to have a predetermined positional relationship with respect to, and is stacked on a pressing jig (or already laminated substrates). After that, water is sprayed to form a water film on the upper surface of the spacer 21. Then, the substrate 1 (in this example, the blocking film on the main surface of the substrate has been removed) is taken out from the cassette for substrates (not shown) by the robot 85 for taking out the substrate with its main surface facing downward. , Placed on the substrate stage 83. After the substrate is positioned on the substrate stage 83 such that the center and notch of the substrate or the orientation flat has a predetermined positional relationship with the holding surface of the substrate transfer robot 87, the substrate is transferred by the substrate transfer robot 87. Hold on the substrate holder,
The stacking stage 81 is conveyed and stacked on the spacer so as to have a predetermined positional relationship with the stacking stage 81. At this time,
A water film is formed on the peripheral portion of the substrate by the annular porous body 41 containing water of the water film forming means.

After the above-mentioned operations are repeated to stack a predetermined number of substrates, and finally one spacer is similarly stacked, the pressing jig 34 is further placed on the spacer to form a laminated body. To finish. Using a stack transfer machine (not shown), install the stack on the stack holder of the etching unit so that the central axis of the stack matches the rotation axis of the stack of the etching unit. Through the pressurizing mechanism (for example, the pressurizing spindle 33 in FIG. 3), it is tightened with a predetermined load.

FIG. 3 also schematically shows an example of a method of pressing the laminated body adhered by water bonding uniformly at the peripheral portion of the substrate and with a force larger than other portions. A laminated body constituted by alternately sticking a plurality of substrates 1 and spacers 21 by water bonding is used to form a laminated body holder 32, 32 'in which the central portion of the pressing surface is counterbored through a pressing jig 34, 34'. Then, the pressure spindle 33 is operated to apply pressure to the laminated body.

[0067]

According to the present invention, the blocking film in the chamfered portion of the substrate can be selectively removed so that the shape of the blocking film on the back surface of the silicon single crystal substrate for an epitaxial wafer does not become uneven. It is possible to effectively prevent the generation of nodules in the chamfered portion when growing the. Further, the removal of the blocking film at the chamfered portion can be performed with high productivity, efficiently and accurately.

[Explanation of Terms] 1. Epitaxial layer: A crystal epitaxially grown on the main surface of the substrate 2. Oxide film: Direct oxidation or CVD on the outer surface of the substrate
2. An oxide film formed by a method or the like 3. Blocking film: a film formed on the outer surface of the substrate to prevent the diffusion of the dopant element in the substrate into the gas phase. Main surface: Main outer surface of substrate on which epitaxial layer is grown 5. Back surface: Main outer surface of substrate opposite to main surface 6. Main outer surface: A flat outer surface occupying a main part of a substrate, a thin plate, or a spacer. Peripheral processing surface: The portion where the blocking film is to be removed, including the chamfered portion of the substrate. It corresponds to a portion which is exposed when the laminate is formed and is substantially brought into contact with the etching solution. Further, the expression “substantially” or “substantially” means that the relevant state is in a situation close to the strict meaning.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of the configuration of an etching section in the apparatus of the present invention.

FIG. 2 is a schematic view illustrating the shape of a substrate and a thin plate of the present invention and a part of a laminated body.

FIG. 3 is a schematic diagram showing an example of the structure of a laminate described in the present invention.

FIG. 4 is a schematic view showing an example of the structure of a water film forming means described in the present invention.

FIG. 5 is a schematic diagram showing an example of a conventional method for removing a blocking film on a chamfered portion of a substrate as a laminate.

FIG. 6 is a schematic view showing an example of a conventional method for removing a blocking film on a chamfered portion of a substrate.

FIG. 7 is a schematic view showing another example of a conventional method for removing a blocking film on a chamfered portion of a substrate.

FIG. 8 is a schematic view showing an example of the configuration of a stacking unit in the device of the present invention.

FIG. 9 is a process flow diagram showing processing steps according to the method of the present invention corresponding to the configuration of the apparatus.

FIG. 10 is a schematic diagram of the irregular shape observed on the periphery of the blocking film.

[Explanation of symbols]

1 substrate 2 blocking membrane 3 Edge-treated surface or blocking film on exposed part 11 laminate 13 Etching liquid supply pipe 15 pores 16 brushes 17 Brush Hair 21 Thin plate or chamfer spacer 22 Thin plate or small diameter spacer 32, 32 'Pressure jig or laminate holder 33 Pressure spindle 34, 34 'holding jig 41 Porous body 51 spacer 52 Tightening jig 53 Hydrofluoric acid 54 Etching tank 61 Nonwoven 62 heads 71 grinding wheel 81 Stacking stage 82 thin plate stage 83 Substrate stage 84 Thin plate take-out robot 85 Substrate removal robot 86 Thin plate transfer robot 87 Substrate transfer robot

Claims (20)

[Claims] 1. A laminated body in which one or a plurality of substrates each having a thin film formed on an outer surface thereof are exposed at least at a portion including a chamfered portion and sandwiched by thin plates having substantially the same shape as the substrate,
A method for producing a silicon single crystal substrate for an epitaxial wafer, which comprises contacting a substantially entire surface of the exposed portion of the substrate while renewing an etching solution to selectively remove only a thin film on the surface of the exposed portion of the substrate. . 2. A laminated body in which one or a plurality of substrates each having a thin film formed on an outer surface thereof are exposed at least at a portion including a chamfered portion and sandwiched by thin plates having substantially the same shape as the substrate,
A step of immersing the laminated body in the etching solution while stirring, or a step of immersing the laminated body in the etching solution while rotating the laminated body around an axis perpendicular to the main outer surface of the substrate;
Alternatively, at least one step is selected from the steps of immersing the laminate in an agitating etching solution while rotating it about an axis perpendicular to the main outer surface of the substrate, and the surface of the exposed part of the substrate is selected. The method for producing a silicon single crystal substrate for an epitaxial wafer, characterized in that the etching liquid is renewed and brought into contact with substantially the entire region of the substrate to selectively remove only the thin film on the surface of the exposed portion of the substrate. 3. A laminated body in which one or a plurality of substrates each having a thin film formed on an outer surface thereof are exposed at least a portion including a chamfered portion and sandwiched by thin plates having substantially the same shape as the substrate,
While the stack is rotated around an axis perpendicular to the main outer surface of the substrate, a brush is used to bring the etching solution into contact with substantially the entire surface of the exposed portion of the substrate while contacting the thin film on the surface of the exposed portion of the substrate. A method for manufacturing a silicon single crystal substrate for an epitaxial wafer, which comprises selectively removing only the above. 4. The method for producing a silicon single crystal substrate for an epitaxial wafer according to claim 3, wherein the brush is rotated in the same direction as the rotating direction of the laminated body, or is swung. 5. The laminated body of a substrate and a thin plate according to claim 1, 2 or 3, wherein a laminated body of the substrate and the thin plate is formed by sandwiching the substrate with water interposed between the substrate and the thin plate. A method for manufacturing a silicon single crystal substrate for an epitaxial wafer, characterized in that 6. The thin layer body according to claim 1, 2, 3 or 5, wherein a pressure is applied to at least a peripheral portion of the substrate in a direction perpendicular to a main outer surface of the substrate to form a laminate of the substrate and the thin plate. A method of manufacturing a silicon single crystal substrate for an epitaxial wafer, which is characterized in that 7. A silicon single crystal substrate for an epitaxial wafer, characterized in that the thin layer body according to claim 1, 2, 3, 5 or 6 is formed by using a thin plate whose peripheral edge is chamfered. Method. 8. An epitaxial device, characterized in that the thin layer body according to claim 1, 2, 3, 5 or 6 is formed by using a thin plate having substantially the same shape as the shape of a thin film left without being removed. Manufacturing method of silicon single crystal substrate for wafer. 9. The method for producing a silicon single crystal substrate for an epitaxial wafer according to claim 1, wherein the thin film formed on the outer surface of the substrate is an oxide of silicon. 10. The method for producing a silicon single crystal substrate for an epitaxial wafer according to claim 1, wherein the etching liquid is hydrofluoric acid. 11. A laminate comprising one or a plurality of substrates each having a thin film formed on the outer surface, at least a portion including a chamfered portion thereof being exposed, and sandwiched by thin plates having substantially the same shape as the substrate, to obtain a laminate. An apparatus for producing a silicon single crystal substrate for an epitaxial wafer, characterized in that the etching liquid is renewedly contacted with substantially the entire area of the surface to selectively remove only the thin film on the surface of the exposed portion of the substrate. 12. A stacking unit which constitutes a laminated body by sandwiching one or a plurality of substrates each having a thin film formed on the outer surface between thin plates having substantially the same shape as the substrate so that at least a portion including the chamfered portion is exposed, An etching unit for etching the thin film of the substrate exposed portion of the laminate by contacting the thin film on substantially the entire surface of the laminate while updating the etching liquid; and an unstacking unit for separating the etched laminate into a substrate and a thin plate, An apparatus for producing a silicon single crystal substrate for an epitaxial wafer, which selectively removes only the thin film on the surface of the exposed portion of the substrate. 13. The stacking portion has a water film forming means for allowing water to be interposed between the substrate and the thin plate so that the substrate can be sandwiched between the thin plates, according to claim 11 or 12. Equipment for manufacturing silicon single crystal substrates for epitaxial wafers. 14. The etching section has a laminated body pressure holding mechanism for applying a pressure in a direction perpendicular to the main outer surface of the substrate at least at the peripheral portion of the substrate to sandwich the substrate between the thin plates. Item 11. An apparatus for producing a silicon single crystal substrate for an epitaxial wafer according to item 11 or 12. 15. A laminate in which substrates are sandwiched between thin plates is freely wrapped around a central axis of the substrate so that the center of the principal outer surface of the substrate coincides with the central axis of the substrate perpendicular to the principal outer surface. To rotate the brush-implanted rod-shaped brush around its central axis, and to keep the central axes of the stack and the rod-shaped brush substantially parallel to each other, and to move them closer to or away from each other. Means for supplying the etching liquid to the surface of the exposed portion of the substrate through the brush of the brush, and the brush of the rod-shaped brush is rubbed on substantially the entire surface of the exposed portion of the substrate. 15. The apparatus for manufacturing a silicon single crystal substrate for an epitaxial wafer according to claim 13 or 14. 16. The method according to claim 11, further comprising means for controlling at least one of the temperature and the supply amount of the etching solution, or a means for simultaneously controlling the temperature and the supply amount of the etching solution. An apparatus for producing a silicon single crystal substrate for an epitaxial wafer as described. 17. The apparatus for producing a silicon single crystal substrate for an epitaxial wafer according to claim 11 or 12, further comprising a cleaning liquid supply means for cleaning the laminated body or a portion other than the laminated body. 18. The epitaxial wafer according to claim 17, further comprising means for controlling at least one of the temperature and the supply amount of the cleaning liquid, or a means for simultaneously controlling the temperature and the supply amount of the cleaning liquid. Equipment for manufacturing silicon single crystal substrates. 19. The rotation direction and rotation speed of the substrate and the rotation direction of the brush are individually operated by a mechanism for rotating the laminated body, a mechanism for rotating the rod-shaped brush, or a mechanism for changing the distance between the substrate and the brush. 16. The apparatus for manufacturing a silicon single crystal substrate for an epitaxial wafer according to claim 11, 12 or 15, further comprising means for controlling a rotation speed and a rotation speed, or a distance between the substrate and the brush. 20. A stacking portion is a substrate stock means,
A thin plate stocking means, a substrate taking-out means, a thin plate taking-out means, a substrate stage, a thin plate stage, a substrate carrying means, a thin plate carrying means, a water film forming means, and a stacking stage are provided, and a thin plate is taken out from the thin plate stocking means by the thin plate taking-out means. It is conveyed to the top, placed so that the center axis of the thin plate matches the center axis of the thin plate stage, positioned on the thin plate stage, and then transferred to the stacking stage by the thin plate conveying means, and the thin plate center axis is set to the stacking stage center axis The thin plate is placed on the stacking stage so that the sheets match each other, the water film is formed on the upper surface of the thin plate by the water film forming means, and then the substrate is taken out from the substrate stocking means by the substrate taking out means.
It is transported to the substrate stage, placed so that the central axis of the substrate matches the central axis of the substrate stage, positioned on the substrate stage, and then transported to the stacking stage by the substrate transport means, and the central axis of the substrate is centered on the stacking stage. The substrate is placed on the thin plate placed on the stacking stage so as to match the axis, a water film is formed on the upper surface of the substrate by the water film forming means, and then the second thin plate is formed in the same manner as above. After that, the water film is formed by placing it on the substrate, and thereafter, the substrate and the thin plates are alternately stacked on the stacking stage to place a predetermined number of substrates, and finally the thin plates are placed and laminated. 13. The apparatus for manufacturing a silicon single crystal substrate for an epitaxial wafer according to claim 12, which is configured to form a body.