JP2008171917A - Stencil mask and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stencil mask assuring excellent heat radiating characteristic with less influence of crystal defect and also assuring processing characteristic and moreover provide a method for manufacturing the same stencil mask. <P>SOLUTION: The stencil mask is characterized in that a heat radiating film is formed of a carbon material and thickness of the heat radiating film is 0.1 μm or more. Therefore, heat conductivity can be improved drastically and flexure of membrane due to generation of heat can be controlled. Accordingly, the stencil mask can be expected for suitable use particularly in ion injecting step. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a stencil mask and a stencil mask manufacturing method, and more particularly to a stencil mask and a stencil mask manufacturing method used in an ion implantation process.

  In a semiconductor device manufacturing process, a group 3 element such as boron or gallium or a group 5 element such as phosphorus, arsenic, or antimony is ion-implanted into a predetermined portion of silicon as a dopant to have p-type or n-type conductivity. A semiconductor layer is formed.

  The ion implantation apparatus is an apparatus for producing ions made of a predetermined element, accelerating the ions, and implanting ions into a target substrate. Therefore, in order to implant ions into a predetermined location on the semiconductor substrate, the non-ion implantation region must be masked by some means.

  Conventionally, as a method for masking a non-ion implantation region, a method using a resist film or a silicon oxide film formed on a semiconductor substrate has been taken. By patterning these films using a photolithography technique or the like to form openings, it is possible to distinguish between the ion implantation region and the non-ion implantation region. However, this method requires a pre-treatment such as resist coating, exposure, and development, and post-treatment such as resist removal and washing, which is a very long process and has been regarded as a problem in terms of construction period and manufacturing cost.

  Under such circumstances, an ion implantation technique using a stencil mask has been proposed and developed. In a stencil mask for ion implantation, bending of the membrane due to heat generation is a big problem. Since the non-ion implantation region is masked by the stencil mask, a large amount of high energy ion beam is also implanted into the membrane portion of the stencil mask. As a result, for example, in the membrane portion of the stencil mask in which the pattern layer is formed of silicon, the temperature may reach several hundred degrees depending on the ion implantation amount. There is a problem that the silicon membrane at a high temperature is bent and the dimensional accuracy and position accuracy of the ion implantation region are extremely deteriorated.

  In view of this, a stencil mask for ion implantation using diamond having a thermal conductivity higher than that of silicon for the pattern layer has been proposed (see Patent Document 1).

As a stencil mask used in the charged particle exposure process, a method of forming a film mainly composed of carbon on a thin film silicon membrane has been proposed (see Patent Document 2).
JP 2005-12187 A JP-A-2005-93484

  However, compared to silicon membrane masks, diamond membrane masks are inferior in terms of crystal integrity. Therefore, for example, there is a problem that ions that have passed through pinhole defects or the like of the diamond membrane are implanted into the non-ion implantation region of the target substrate. In addition, there is a problem in terms of reliability, such as a mask being damaged during use starting from a stacking fault or a dislocation defect. In addition, the precision processing technology of diamond itself is difficult and has a problem that it is very difficult to use.

  Further, in the method of forming the heat dissipation film on the back surface side after forming the through hole in the pattern layer, the heat dissipation film may reduce the size of the through hole pattern. The above-described problem becomes significant when the heat dissipation film is formed thick.

  Therefore, the present invention has been made to solve the above-described problems, and provides a stencil mask and a stencil mask manufacturing method that have good heat dissipation, little influence of crystal defects, and excellent processing characteristics. Objective.

  The present invention described in claim 1 includes at least a pattern layer provided with a through-hole pattern, a base material that supports the pattern layer, and a heat-dissipating film that protects the through-hole pattern. The stencil mask is a film having a main component, wherein the heat dissipation film has a thickness greater than 0.1 μm.

  The present invention described in claim 2 is the stencil mask according to claim 1, wherein the pattern layer is silicon, and the film thickness of the pattern layer is 2 μm or more and 60 μm or less. is there.

  A third aspect of the present invention is the ion implantation mask according to the first or second aspect, wherein the heat dissipation film is a diamond film or a diamond-like carbon film. is there.

  The present invention according to claim 4 is the stencil mask according to any one of claims 1 to 3, wherein the heat dissipation film is selected from the group consisting of boron, sulfur, nitrogen, phosphorus, and silicon. A stencil mask characterized by containing more than one kind of impurities.

  The stencil mask according to claim 5 includes at least a step of patterning a pattern layer, a step of forming a heat dissipation film, and a step of forming a through-hole pattern in the heat dissipation film. It is a manufacturing method.

  The present invention according to claim 6 is the stencil mask manufacturing method according to claim 5, wherein the pattern layer is silicon, the heat dissipation film is a film containing carbon as a main component, and a through hole pattern is formed in the heat dissipation film. The step of forming a stencil mask manufacturing method is a step of performing dry etching using a gas containing oxygen as a main component.

  The present invention according to claim 7 is the stencil mask manufacturing method according to claim 5 or 6, wherein a substrate including a base material, an intermediate layer, and a pattern layer is used, and the intermediate layer is formed. Etching the substrate as an etching stopper, forming the membrane part, removing the intermediate layer in contact with the membrane part, forming the heat dissipation film from the substrate side, etching the pattern layer, and patterning A method for manufacturing a stencil mask, comprising: a step of performing, and a step of etching from the pattern layer side to form a through hole in the heat dissipation film.

  The present invention according to claim 8 is the stencil mask manufacturing method according to claim 5, wherein a substrate including a base material, an intermediate layer, and a pattern layer is used, and the intermediate layer is formed. Etching the pattern layer as an etching stopper to perform patterning, etching the substrate using the intermediate layer as an etching stopper to form a membrane part, removing the intermediate layer in contact with the membrane part, A stencil mask manufacturing method comprising: a step of forming a heat dissipation film from a material side; and a step of etching from a pattern layer side to form a through hole in the heat dissipation film.

  The present invention according to claim 9 is the stencil mask manufacturing method according to claim 7 or 8, wherein the substrate is an SOI substrate.

  In the stencil mask of the present invention, the heat dissipation film is made of a carbon material, and the film thickness of the heat dissipation film is larger than 0.1 μm. Since the heat dissipation characteristics improve as the film thickness of the heat dissipation film increases, the thermal conductivity can be improved. For this reason, bending of the membrane due to heat generation can be suppressed.

  Hereinafter, one embodiment of the stencil mask of the present invention will be described with reference to FIG.

The stencil mask 10 of the present invention is
A pattern layer 4 provided with a through-hole pattern 7;
A substrate 2 for supporting the pattern layer 4;
A heat dissipation film 1 that protects the through-hole pattern 7, and the heat dissipation film 1 is a film mainly composed of carbon,
The stencil mask is characterized in that the thickness of the heat dissipation film 1 is larger than 0.1 μm.

  The pattern layer is preferably made of a material having few crystal defects so that ions that have passed through pinhole defects and the like are not implanted into the non-ion implantation region of the target substrate in the ion implantation step. For example, silicon or the like may be used.

  When the pattern layer is silicon, the thickness of the pattern layer is preferably 2 μm or more and 60 μm or less. When the thickness is 2 μm or less, the membrane is likely to be deformed or broken during ion implantation. When the thickness is 60 μm or more, the pattern accuracy of the through hole pattern may be deteriorated.

  The substrate may be any shape and material that can support the pattern layer, and the shape and material are not particularly limited. For example, you may provide the beam which supports a membrane part.

  The heat dissipation film is preferably a material having excellent thermal conductivity, and more preferably a film containing carbon as a main component. At this time, as the film containing carbon as a main component, a diamond film or a diamond-like carbon film made of polycrystal or nanocrystal can be preferably used. Carbon nanotubes, fullerenes, amorphous carbon, and the like can also be used.

In particular, in the case of a stencil mask used in the ion implantation process, the ion implantation depth of ions implanted into the target substrate is generally 0.1 μm or less, so that the membrane portion is not affected by ion implantation. The heat dissipation film is preferably larger than 0.1 μm. By making the heat dissipation film larger than 0.1 μm, the energy injected into the stencil mask can be absorbed and dissipated by the heat dissipation film. Therefore, the pattern layer can be protected from the implanted ions.

  Moreover, since the heat dissipation characteristic improves as the film thickness increases, the heat dissipation film is preferably thick. For this reason, the film thickness of the heat dissipation film is preferably larger than 0.1 μm, and more preferably larger than 0.5 μm.

  The heat dissipation film preferably contains at least one impurity selected from the group consisting of boron, sulfur, nitrogen, phosphorus, and silicon. Thereby, since the heat dissipation film has conductivity, it is possible to prevent ion implantation failure and mask damage due to charge-up.

  The through-hole pattern is an opening pattern that penetrates both the pattern layer and the heat dissipation film. In the ion implantation step, impurity ions are implanted into a desired portion of the target substrate through the through hole pattern.

  Hereinafter, the manufacturing method of the stencil mask of this invention is demonstrated.

The method for producing the stencil mask of the present invention includes:
Patterning the pattern layer;
Forming a heat dissipation film;
Forming a through hole pattern in the heat dissipation film.

<Step of patterning the pattern layer>
As a process of patterning the pattern layer, a known patterning method can be used as appropriate. For example, the pattern layer may be formed using a known lithography technique and a known etching technique.

<Process for forming heat dissipation film>
As the step of forming the heat dissipation film, a known thin film forming method can be used as appropriate, and for example, it may be formed using a chemical vapor deposition method.

<Step of forming a through hole pattern in the heat dissipation film>
As a process of forming a through-hole pattern in the heat dissipation film, a known patterning method can be used as appropriate, and for example, a known lithography technique and a known etching technique may be used.

  By forming the through hole pattern in the heat dissipation film after forming the heat dissipation film, it is possible to suppress deformation of the dimension of the through hole pattern by the heat dissipation film. For this reason, even when the film thickness of the heat dissipation film is particularly thick, the dimensional variation of the through hole pattern can be suppressed. Therefore, it can be suitably used particularly for manufacturing a stencil mask having a thick heat dissipation film.

  When the pattern layer is silicon and the heat dissipation film is a film containing carbon as a main component, the step of forming a through hole pattern in the heat dissipation film is a step of performing dry etching using a gas containing oxygen as a main component. It is preferable. Dry etching using a gas containing oxygen as a main component has a higher etching rate than silicon for a film containing carbon as a main component. For this reason, the pattern provided in the pattern layer can be used as a mask for forming the through-hole pattern of the heat dissipation film. Therefore, the effective dimensional variation of the through hole pattern can be suppressed and the through hole can be formed in the heat dissipation film.

  Hereinafter, one embodiment of the method for producing a stencil mask of the present invention will be specifically described with reference to FIGS. 2 (a) to 2 (f).

<Process for etching the substrate to form the membrane part>
First, a substrate provided with a base material, an intermediate layer, and a pattern layer is prepared (FIG. 2A). The substrate and the pattern layer need only satisfy the above-mentioned requirements, and the intermediate layer may be any layer that functions as a stopper layer for the etching treatment with respect to the substrate and the pattern layer.

  At this time, an SOI substrate can be preferably used as the substrate. The SOI substrate is a substrate in which single crystal silicon is formed over an insulating film. At this time, an insulating film can be used as an intermediate layer and single crystal silicon can be used as a pattern layer. Since the SOI substrate is distributed as a semiconductor material, it is easily available and has a structure of at least three layers with an insulating film interposed therebetween. Therefore, the SOI substrate can be suitably used in the stencil mask manufacturing method of the present invention.

  Next, the base material is etched to form the base material side opening 210 (FIG. 2B). At this time, a known patterning method can be used as appropriate, and for example, it may be formed using a known lithography technique and a known etching technique. At this time, by performing patterning so that the base material portion remains in a part of the base material side opening 210, a beam that supports the membrane portion of the stencil mask can be formed.

<Step of removing the intermediate layer in contact with the membrane>
Next, the intermediate layer 120 in the base material side opening 210 is removed, and the membrane part 220 is formed (FIG. 2C). As the removing step, a known thin film removing method can be used as appropriate, and for example, it may be removed using a known etching technique.

<Step of forming a heat dissipation film from the substrate side>
Next, the heat radiation film 230 is formed on the surface of the membrane portion 220 on the substrate side and the surface of the substrate (FIG. 2D). The heat dissipating film is preferably a film containing carbon as a main component, and may be appropriately formed using a known forming method. For example, when a diamond film or a diamond-like carbon film is formed as the heat dissipation film, it may be formed using a chemical vapor deposition method.

<Process for patterning by etching the pattern layer>
Next, a desired pattern 240 is formed on the membrane 220 (FIG. 2E). As a process of patterning the pattern layer, a known patterning method can be used as appropriate. For example, the pattern layer may be formed using a known lithography technique and a known etching technique. At this time, in the patterning step, there is no intermediate layer immediately below the membrane portion of the pattern layer. For this reason, it is possible to perform patterning without considering the distortion caused by the stress of the intermediate layer, and the pattern position accuracy can be improved. In particular, when an SOI substrate is used, it is effective because it is not affected by the distortion of the insulating film.

<Process for forming through holes in heat dissipation film>
Next, the through-hole pattern 250 is formed in the heat dissipation film 230 to obtain the stencil mask of the present invention (FIG. 2 (f)). As a process of forming a through-hole pattern in the heat dissipation film, a known patterning method can be used as appropriate, and for example, a known lithography technique and a known etching technique may be used. When the SOI substrate is used, the step of forming the through hole in the heat dissipation film is preferably a step of performing dry etching using a gas containing oxygen as a main component. Dry etching using a gas containing oxygen as a main component has a higher etching rate than silicon for a film containing carbon as a main component. For this reason, the through-hole pattern provided in the pattern layer can be used as a mask for forming the through-hole pattern of the heat dissipation film. Therefore, the effective dimensional variation of the through hole pattern can be suppressed and the through hole can be formed in the heat dissipation film.

  Hereinafter, another embodiment of the stencil mask manufacturing method of the present invention will be specifically described with reference to FIGS. 3 (a) to 3 (f).

<Process for patterning by etching the pattern layer>
First, a substrate is prepared (FIG. 3A). The substrate may be prepared in the same manner as in the above embodiment.

  Next, the pattern layer is etched and patterned by using the intermediate layer as an etching stopper (FIG. 3B). At this time, in the patterning process, the intermediate layer 120 and the base material 110 exist immediately below the pattern 310. At this time, the dimensional accuracy of the pattern 310 can be improved by adjusting the temperature of the substrate.

<Step of etching the base material to form the membrane portion> (FIG. 3C)
<Step of removing the intermediate layer in contact with the membrane> (FIG. 3D)
<Step of forming a heat dissipation film from the substrate side> (FIG. 3E)
<Step of forming a through-hole in the heat dissipation film> (FIG. 3F)
About these processes, you may carry out similarly to the above-mentioned embodiment.

  As mentioned above, it can implement about the manufacturing method of the stencil mask of this invention.

  Hereinafter, an ion implantation process using the stencil mask of the present invention will be described with reference to FIG.

  FIG. 4 is an enlarged view of the vicinity of the stencil mask in the ion implantation apparatus. An ion beam 400 is implanted into the target substrate 410 through the stencil mask 10. At this time, the stencil mask 10 is installed so that the heat dissipation film 1 is on the ion beam side. By disposing the heat radiation film 1 on the ion beam side, heat from the ion beam is released to the chuck 420 through the heat radiation film 1, so that the membrane portion of the stencil mask for ion implantation is prevented from being bent by heat. I can do it.

<Example 1>
First, an SOI substrate (pattern layer thickness: 20 μm, base material thickness: 525 μm) was prepared (FIG. 2A).

  Next, a resist is applied to the surface of the substrate 110, and a predetermined opening resist pattern is formed by using a photolithography technique. Using the opening resist pattern as a mask, the intermediate layer 120 is used as an etching stopper, and a fluorine-based gas is used. The substrate 110 was dry-etched to form a substrate-side opening 210, and the opening resist pattern was removed using a mixed solution of sulfuric acid and hydrogen peroxide solution (FIG. 2B).

  Next, using a 5% hydrofluoric acid solution, the intermediate layer 120 in the substrate-side opening 210 was removed to form a membrane portion 220 (FIG. 2C).

  Next, a diamond film having a thickness of 0.5 μm was formed on the surface of the membrane 220 on the substrate side and the substrate surface by a chemical vapor deposition method as the heat dissipation film 230 (FIG. 2D).

  Next, a resist was applied to the surface of the pattern layer, and a predetermined resist pattern was formed using EB lithography technology. Using the resist pattern as a mask, the membrane 220 was dry etched using a fluorine-based gas to form a pattern 240, and the resist was removed using a mixed solution of sulfuric acid and hydrogen peroxide (FIG. 2 (e)). .

  Next, the diamond film was dry-etched using oxygen gas using the pattern 240 as a mask to form a through-hole pattern 250, and the stencil mask of the present invention was manufactured (FIG. 2 (f)).

<Example 2>
First, an SOI substrate (pattern layer thickness: 20 μm, base material thickness: 525 μm) was prepared (FIG. 3A).

  Next, a resist was applied to the surface of the pattern layer 130, and a predetermined resist pattern was formed using EB lithography technology. Using the resist pattern as a mask, using the intermediate layer 120 as an etching stopper, dry etching is performed using a fluorine-based gas to form a pattern 310 on the pattern layer 130, and using a mixed solution of sulfuric acid and hydrogen peroxide solution, the resist is formed. It removed (FIG.3 (b)).

  Next, a resist is applied to the surface of the substrate 110, a predetermined opening resist pattern is formed using a photolithography technique, the opening resist pattern is used as a mask, the intermediate layer 120 is used as an etching stopper, and a fluorine-based gas is used. Was used to dry-etch the substrate 110 to form the substrate-side opening 320, and the resist was removed using a mixed solution of sulfuric acid and hydrogen peroxide. (FIG. 3C).

  Next, a part of the intermediate layer 120 was removed using a 5% hydrofluoric acid solution to form a pattern 330 (FIG. 3D).

  Next, a diamond film having a thickness of 0.5 μm was formed as a heat dissipation film 230 on the substrate side surface and the substrate surface of the pattern 330 by chemical vapor deposition (FIG. 3E).

  Next, the diamond was dry-etched using oxygen gas using the pattern 330 as a mask to form a through-hole pattern 350, and the stencil mask of the present invention was manufactured (FIG. 2 (f)).

  The stencil mask of the present invention is excellent in heat dissipation, and therefore can be expected to be suitably used as a stencil mask used particularly in the ion implantation process.

It is the schematic which shows an example of the stencil mask of this invention. It is sectional process drawing which shows one Embodiment of the stencil mask manufacturing method of this invention. It is sectional process drawing which shows one Embodiment of the stencil mask manufacturing method of this invention. It is explanatory drawing which shows the ion implantation process using the stencil mask of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Stencil mask 2 ... Base material 3 ... Intermediate | middle layer 4 ... Pattern layer 5 ... Membrane part 6 of pattern layer ... Membrane part 7 of thermal radiation film | membrane ... Through-hole pattern 100 ... SOI substrate 110 ... Base material 120 ... Intermediate layer 130 ... Pattern layer 210, 320 ... Base material side opening 220 ... Membrane portion 230, 340 ... Heat radiation film 240, 310, 330 ... Pattern layer pattern 250, 350 ... Through-hole pattern 400 ... ion beam 410 ... target substrate 420 ... chuck

Claims (9)

A pattern layer provided with a through-hole pattern;
A substrate supporting the pattern layer;
A heat dissipation film that protects the through-hole pattern, and the heat dissipation film is a film mainly composed of carbon,
A stencil mask, wherein the thickness of the heat dissipation film is larger than 0.1 μm. A stencil mask according to claim 1,
The pattern layer is silicon,
The stencil mask, wherein the pattern layer has a thickness of 2 μm or more and 60 μm or less. A stencil mask according to claim 1 or 2,
A stencil mask, wherein the heat dissipation film is a diamond film or a diamond-like carbon film. A stencil mask according to any one of claims 1 to 3,
The stencil mask, wherein the heat dissipation film contains at least one impurity selected from the group consisting of boron, sulfur, nitrogen, phosphorus, and silicon. at least,
Patterning the pattern layer;
Forming a heat dissipation film;
And a step of forming a through-hole pattern in the heat dissipation film. A stencil mask manufacturing method according to claim 5,
The pattern layer is silicon,
The heat dissipation film is a film mainly composed of carbon,
The method of manufacturing a stencil mask, wherein the step of forming the through hole pattern in the heat dissipation film is a step of performing dry etching using a gas containing oxygen as a main component. A method for producing a stencil mask according to claim 5 or 6,
Using a substrate including a base material, an intermediate layer, and a pattern layer, using the intermediate layer as an etching stopper, etching the base material, and forming a membrane part;
Removing the intermediate layer in contact with the membrane part;
Forming a heat dissipation film from the substrate side;
Etching the pattern layer and patterning;
Etching from the pattern layer side, forming a through hole in the heat dissipation film,
A method for producing a stencil mask, comprising: A method for producing a stencil mask according to claim 5 or 6,
Using a substrate including a base material, an intermediate layer, and a pattern layer, etching the pattern layer using the intermediate layer as an etching stopper, and patterning;
Using the intermediate layer as an etching stopper, etching the base material to form a membrane part,
Removing the intermediate layer in contact with the membrane part;
Forming a heat dissipation film from the substrate side;
Etching from the pattern layer side, forming a through hole in the heat dissipation film,
A method for producing a stencil mask, comprising: A stencil mask manufacturing method according to claim 7 or 8,
A stencil mask manufacturing method, wherein the substrate is an SOI substrate.

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