JPH07152150A - Aperture - Google Patents

Abstract

PURPOSE:To prevent the deformation and dissolution of an aperture by heat by imparting a layer consisting of a material having the thermal conductivity higher than the thermal conductivity of a main material forming the aperture to a first region. CONSTITUTION:Back etching is executed by a heated etching liquid 4 which is a KOH soln. from the rear surface side of a substrate 1 consisting of an Si single crystal, by which anisotropic etching is executed. The substrate is thereafter washed by pure water, by which a blank 5 of the aperture is obtd. An electron beam resist 6 is applied on the surface of this bank 5 on the side opposite to its aperture. Next, a metallic film 8 is formed by a vacuum vapor deposition method on a resist pattern 7 atop the blank 5. The metallic film 8 consists preferably of the material which has the thermal conductivity higher than the thermal conductivity of the main material of the aperture, i.e. Si, and is not attacked by an etching liquid 4 for the Si. Ag is used in this embodiment. Next, the substrate formed with the metallic film 8 is immersed into the heated KOH soln. which is the etching liquid 4 for the Si. Peeling of the masking pattern 2 is thereafter executed and the pattern is washed by pure water and dried, by which the aperture 9 is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aperture in a batch exposure type charged beam exposure apparatus used for forming a fine pattern of a semiconductor integrated circuit, etc. The present invention relates to an aperture of a charged beam exposure apparatus in which the beam forming means is improved to achieve the above.

[0002]

2. Description of the Related Art The pattern of a semiconductor integrated circuit tends to be miniaturized year by year and has become complicated. In order to draw and form such a pattern with a charged beam exposure apparatus, a so-called collective exposure method, block exposure method, character projection method, etc., in which a repeatedly used figure or figure group is drawn in one shot Has been proposed.

In this system, the aperture in the charged beam exposure apparatus is changed to one in which a round hole is formed in the conventional point beam system and a rectangular hole is formed in the variable shaped beam system, and a figure or a pattern used repeatedly is used. A drastic improvement in throughput is expected with the idea that drawing is performed in a single shot by creating a group of figures.

By the way, in the aperture used in this system, conventionally, for example, as shown in FIG. 3 (j), a thick Si substrate 12 is used as a supporting substrate to perform chemical etching according to the azimuth plane from the back side, and the upper surface thereof is subjected to chemical etching. A thin Si substrate 11 bonded together, or a thick Si substrate as shown in FIG.
The substrate 1 is chemically etched from the back according to the azimuth plane, the upper surface is made thin, and a figure and a figure group that are repeatedly used are formed in that portion.

However, in the method of FIG. 3, as shown in FIG. 3A, first, the Si substrate 1 which is a supporting substrate is prepared,
As shown in (b), a masking pattern 2 is formed on the back surface of the supporting substrate, and as shown in (c), chemical etching is performed using a Si etching solution 4 (reference numeral 3 is an etching bath) to obtain Si. As shown in (f), the Si substrate 11 on the upper surface is bonded onto the substrate 12 via the silicon oxide 10 and the Si substrate 11 on the upper surface is polished or etched to an appropriate thickness, as shown in (g). Then, a resist 6 is applied thereon, and as shown in (h), the pattern is exposed by light, electron beam, etc., and after development processing is performed to form a resist pattern 7, as shown in (i), There is a step of etching the Si substrate 11 and removing the resist. Further, in the method of FIG. 4, an Si substrate 1 which is a supporting substrate is prepared as shown in FIG. 4A, and a masking pattern 2 is formed on the back surface as shown in FIG.
Chemical etching is performed, and then chemical etching or polishing is performed until the upper surface has an appropriate thickness as shown in (c), a resist 6 is applied thereon as shown in (d), and as shown in (e). After patterning this to form a resist pattern 7, as shown in (f), there is a step of etching the substrate on the upper surface and stripping the resist. In either method of FIG. 3 and FIG. It required complicated steps. In both of the methods of FIG. 3 and FIG. 4, since the upper surface is thinned and then etching is performed,
Since its thickness is several tens to several hundreds of μm, it must be handled with care. Especially, the weight of the resist when applying the resist, the weight of the etching solution during the wet etching, and the vibration and shock during the handling during the process. There was a problem that I could easily shake. Further, when the upper surface is thinned by chemical etching, the film thickness of the upper surface varies depending on when etching is stopped, so that there is a problem that very precise etching control is required.

Further, when the aperture is incorporated in the charged beam exposure apparatus to perform exposure, the portion shielded by the aperture, that is, the portion having no pattern is irradiated with the charged beam. Therefore, the irradiation of the charged beam causes the molecules constituting the aperture to vibrate thermally, and the temperature of itself rises. Therefore, if a substance with poor thermal conductivity is used as the material for the aperture,
The pattern is deformed by the deformation of the aperture due to the temperature rise, the beam passing through it is displaced from the intended position, and in severe cases, the pattern is not drawn at all, or the aperture itself is melted. There was a problem of doing.

[0007]

Therefore, in the present invention, there is a problem with the aperture for a charged beam exposure apparatus that has been used in the conventional exposure method for a charged beam, which is a so-called collective exposure method, that is, the heat of the material of the aperture. It is an object of the present invention to provide an aperture for a charged beam exposure apparatus which is easy to manufacture and has high accuracy, by solving the problem that the pattern is deformed due to the poor conductivity and the pattern is deformed, and the aperture itself is melted. Has an aim.

[0008]

In order to achieve the above object, the aperture of the present invention is used in an exposure method using a charged beam, and includes a first film region having an opening and the first film region.
A second film region thicker than the first film region and supporting the film region of the first film region, the first film region being formed of a material having a higher thermal conductivity than a main material forming the aperture. Is added to at least one layer.

Further, the aperture of the present invention is characterized in that the layer made of a substance having a thermal conductivity higher than that of the main material is a material which is not etched when the main material is etched.

Further, in the aperture of the present invention, the first film region is composed only of a layer made of a substance having a higher thermal conductivity than the main material, and the second film utilization region is composed mainly of the material. It is characterized by becoming.

Further, the aperture of the present invention is characterized in that the second film region is made of Si single crystal.

Further, the aperture of the present invention is characterized in that the main material is Si single crystal.

Further, the aperture of the present invention is characterized in that the substance having a higher thermal conductivity than the main material is Ag.

[0014]

According to the aperture of the present invention, the aperture is composed of the first film region having the opening and the second film region which is the supporting substrate of the first film region, and is more than the main material forming the aperture. Since at least one layer made of a substance having high thermal conductivity is applied to the first film region, for example, when the main material is Si and the layer material having high thermal conductivity is Ag, the heat of Ag is Since the conductivity is about 5 times that of Si,
The heat generated during beam irradiation is dissipated, and the deformation and melting of the aperture due to the heat does not occur.

The main material of the aperture is, for example, S
In the case of i, by using a metal film as the first film region which is the pattern formation region, for example, a substance having a high thermal conductivity such as Ag described above and which is not chemically attacked during Si etching, When etching the first
Since it is possible to perform patterning of the film region at the same time, the manufacturing process can be simplified.

[0016]

Embodiments Embodiments of the aperture of the present invention will be described below with reference to the drawings, but it goes without saying that the present invention is not limited to the embodiments.

FIG. 1 is a sectional view showing an aperture according to an embodiment of the present invention in the order of manufacturing steps.

First, as shown in FIG. 1A, the thickness is 500 μm.
A Si single crystal substrate 1 of m is prepared. The plane orientation of this substrate is (1, 0, 0).

Next, back etching is performed from the back surface side of the substrate 1 with an etching solution 4 of a heated KOH solution. At this time, as shown in FIG. 1B, the masking pattern 2 is formed in a portion other than the opening. The size of the opening is arbitrary, but if the area is too large, the opening is likely to break at the time of completion. Therefore, it is preferably about 500 μm square.
At this time, since the plane orientation of the substrate is (1, 0, 0),
As shown in FIG. 1C, so-called anisotropic etching is performed in which the etching progresses in the thickness direction with respect to the substrate, but does not progress so much in the lateral direction.
The etching is stopped at a plate thickness of the opening portion of about 100 μm, that is, a thickness that does not easily break in the subsequent steps. After that, cleaning is performed with pure water. The masked portion other than the opening, that is, the masking pattern 2 is not peeled off at this stage. This completes the aperture blank 5 as shown in FIG. 1 (d).

Note that this step may be performed after the formation of a pattern described later.

Next, as shown in FIG. 1 (e), an electron beam resist 6 (Tosoh C
Apply MS-EX (R). The film thickness at this time is 20
μm or less. The thickness is preferably 5 to 15 μm. This film thickness becomes the thickness of the pattern formation region that shields the electron beam when completed.

After the predetermined pre-baking process, a conventionally used electron beam drawing device (HL-700 manufactured by Hitachi, Ltd.) is used to draw a pattern, and a predetermined development and post-baking process is performed.

Now, as shown in FIG. 1 (f), the blank 5
A resist pattern 7 is completed on the upper surface of.

Next, on the resist pattern 7 described above, as shown in FIG.
As shown in (g), the metal film 8 is formed by the vacuum evaporation method.
It is desirable that the metal film 8 has a higher thermal conductivity than the main material, that is, Si that is the supporting substrate, and that the metal film 8 is not exposed to the Si etching solution 4. In this embodiment, for example, Ag is used.

At this time, the thickness of the metal film 8 is about the same as the thickness of the resist pattern 7, that is, vacuum deposition is performed until the openings of the resist pattern 7 are filled with the metal film 8. The metal film 8 may be formed by a conventionally known method such as a sputtering method or an ion plating method.

Next, as shown in FIG. 1H, the substrate on which the above-mentioned metal film 8 is formed is immersed in a heated KOH solution which is an etching solution 4 for Si. The etching liquid 4 permeates from the upper surface and the lower surface of the substrate.

Regarding the upper surface, the metal film 8 is also formed on the resist pattern 7, but the metal film 8 is not attached at the boundary between the resist pattern 7 and the opening filled with the metal film 8. It is a thin film, and the etching liquid 4 penetrates from that portion. Since the etching solution 4 is strongly alkaline, it dissolves the resist pattern 7, that is, the electron beam resist 6. Therefore, the resist pattern 7 and the metal film 8 on it are peeled off, and Si underneath is dissolved. However, since the metal film 8 or Ag is insoluble in the etching solution 4, the metal film 8 other than on the resist pattern 7 remains.

On the other hand, regarding the lower surface, the blank 5 described above is used.
The back etching in the manufacturing process of 1), that is, anisotropic etching is performed, and finally Si remains only in the masking pattern 2 portion, and only the metal film 8 formed from the upper surface remains in the opening of the blank 5.

After this, the masking pattern 2 is peeled off, washed with pure water and dried to complete the aperture 9 of the present invention as shown in FIG. 1 (i).

When the apertures produced in this example were mounted on a charged particle beam exposure apparatus and writing was performed, no deformation or melting of the aperture due to heat that was conventionally generated was confirmed even after performing drawing for a long time. It was

In the above embodiment, the thin film portion above the aperture is made of only a substance having a high thermal conductivity. However, the aperture of the present invention may have a structure in which the thin film portion has at least one layer made of a substance having a high thermal conductivity. I don't mind. For example, P
A laminated structure of a conductive metal film such as t or a polysilicon film and Ag may be used.

2A to 2D are sectional views showing an aperture according to another embodiment of the present invention in the order of manufacturing steps. The same parts as those in FIG. 1 are designated by the same reference numerals, and duplicate description will be appropriately omitted.

First, as shown in FIG. 2A, the thickness is 500 μm.
A Si single crystal substrate 1 of m is prepared. The plane orientation of this substrate is (1, 0, 0).

Next, back etching is performed from the back surface side of the substrate 1 with the etching solution 4. At this time, as in the case of FIG.
As shown in (b), the masking pattern 2 is formed in advance in a portion other than the opening. At this time, since the plane orientation of the substrate 1 is (1, 0, 0), so-called anisotropic etching is performed on the substrate as shown in FIG. For etching, the thickness of the opening is 100μ
Stop at a thickness of about m, that is, a thickness that does not easily break in the subsequent steps. After that, cleaning is performed with pure water. The masking pattern 2 masked except for the openings is not peeled off. This completes the blank 5 as shown in FIG. 2 (d). Similar to the above embodiment, this step may be performed after formation of a pattern described later.

Then, the electron beam resist 6 (CMS-EX (R) manufactured by Tosoh Corporation) is applied to the surface of the blank 5 opposite to the opening as shown in FIG. 2 (e). The film thickness at this time is 5
μm.

Then, after a predetermined pre-baking process, a pattern is drawn by the electron beam drawing device (HL-700 manufactured by Hitachi Ltd.), and a predetermined development and post-baking process are carried out, as shown in FIG. 2 (f). A resist pattern 7 is formed on the upper surface of the blank 5.

Next, a metal film 8 is formed on the resist pattern 7 as shown in FIG. 2 (g). The thickness of this metal film 8 was 5 μm. The total film thickness of the metal film 8 and the Si below it becomes the thickness of the pattern forming region that shields the electron beam when completed. The thickness is preferably 5 to 15 μm.

It is desirable that the metal film 8 has a higher thermal conductivity than Si, which is the supporting substrate, and that it is not exposed to the Si etching solution 4. In this embodiment, Ag is used as in the above-described embodiments.

At this time, the thickness of the metal film 8 is the thickness of the resist pattern 7, that is, the opening of the resist pattern 7 is filled with the metal film 8. As described above, the metal film 8 is formed by using the vacuum deposition method, the sputtering method, the ion plating method, or the like.

Next, the above substrate is immersed in a stripping solution for the electron beam resist 6 as shown in FIG. Then, only the resist pattern 7 is dissolved, and the metal film 8 in the portion where the resist pattern 7 is not formed remains without being dissolved, and the metal film pattern 8a is formed.

Next, as shown in FIG. 2 (i), Si, which is the support substrate 1, is etched. A reactive ion etching apparatus (CSE-1 manufactured by Nippon Vacuum Technology Co., Ltd.) which has been conventionally used for a substrate on which the above-described metal film pattern 8a is formed is used.
110) is used to etch to a depth of 10 μm. At this time, in this embodiment, the power is set to 200 W and C
A gas obtained by adding 10% of SF ₆ to l ₂ is used.

At this time, the portion where the metal film 8 is formed is not chemically attacked by the etching gas and therefore is not etched. However, the holes of the metal film pattern 8a are
Since i is exposed, only this portion is etched.

Next, the substrate is taken out from the above-mentioned ion etching apparatus and immersed in the Si etching solution 4 as shown in FIG. 2 (j). On the upper surface, the etching liquid 4 permeates through the openings of the metal film pattern 8a and the etching proceeds in the vertical direction. Also in this case, since the etching is anisotropic as described above, the etching does not proceed so much in the lateral direction.
For the back surface, back etching is continued in the manufacturing process of the blank 5 described above. When the opening of the upper surface metal film pattern 8a and the opening of the back surface are finally connected, the etching is stopped. At this time, the total film thickness of the metal film and Si remaining without being etched was 15 μm.
The cross-sectional shape was tapered as shown in FIGS. 2 (j) and 2 (k).

After this, the masking pattern 2 is peeled off, washed with pure water and dried to complete the aperture 9 of the present invention as shown in FIG. 2 (k).

When the apertures produced in the present example were also mounted on a charged particle beam exposure apparatus to perform drawing, it was confirmed that even if the apertures were drawn for a long time, the deformation and melting of the aperture due to the heat generated conventionally. There wasn't.

[0046]

As described in detail above, according to the aperture of the present invention, the first film region, which is the pattern formation region above the aperture, has a higher thermal conductivity than the main material forming the aperture. Since at least one layer made of a substance is provided, heat generated during beam exposure is dissipated, and as a result, deformation and melting due to heat of the aperture do not occur, which is an excellent effect.

Further, according to the aperture of the present invention, when the main material of the aperture is, for example, Si, the first film region which is a pattern formation region has a metal film, for example, Ag having the thermal conductivity of By using a material that is high and is not chemically attacked when etching Si,
Since the first film region can be patterned at the same time when the main material is etched, the manufacturing process can be simplified.

[Brief description of drawings]

FIG. 1 is a sectional view showing an aperture according to an embodiment of the present invention in the order of manufacturing steps.

FIG. 2 is a sectional view showing an aperture according to another embodiment of the present invention in the order of manufacturing steps.

FIG. 3 is a cross-sectional view showing an example of a conventional aperture manufacturing method in process order.

FIG. 4 is a cross-sectional view showing another example of the conventional method of manufacturing an aperture in the order of steps.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Si substrate 2 Masking pattern 3 Etching tank 4 Si etching liquid 5 Aperture blank 6 Resist 7 Resist pattern 8 Metal film 8a Metal film pattern 9 Aperture of the present invention 10 Si oxide film 11 Upper Si plate 12 Lower Si plate

Claims (6)

[Claims] 1. A first film region used in an exposure method using a charged beam and having an opening, and a second film region supporting the first film region and thicker than the first film region. In the aperture having the above, at least one layer made of a substance having a thermal conductivity higher than that of a main material forming the aperture is applied to the first film region. 2. The aperture according to claim 1, wherein the layer made of a substance having a thermal conductivity higher than that of the main material is a material that is not etched when the main material is etched. 3. The first film region is composed only of a layer made of a substance having a thermal conductivity higher than that of the main material, and
The aperture according to claim 1, wherein the second film region is made of only the main material. 4. The aperture according to claim 1, wherein the second film region is made of Si single crystal. 5. The aperture according to claim 1, wherein the main material is Si single crystal. 6. The aperture according to claim 1, wherein the substance having a thermal conductivity higher than that of the main material is Ag.