JPH07283113A - Aperture and its manufacture - Google Patents

Abstract

PURPOSE:To prevent generation of charge-up and to prevent strain of an aperture by forming a film containing a metal element of high electric conductivity and thermal conductivity all over an aperture surface. CONSTITUTION:A pattern 6 is formed on an Si substrate 1 on the opposite side of an opening part 3 for etching. In the process, a pattern is formed in advance by enlarging a width thereof by a thickness of a film 7 containing a metal element which is formed in a following process. Then, an Si substrate 2 is etched and a resist pattern is removed thereafter. A film containing a metal element is formed in a surface of the aperture. As for a material of the film, tungsten (W) is used. Tungsten has high electric conductivity and high heat conductivity when compared to Si and has equivalent linear expansion coefficient as Si.

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 charged beam exposure apparatus of a shaped beam system, which is used for forming a fine pattern typified by a semiconductor integrated circuit and the like, and a manufacturing technique therefor. The present invention relates to an aperture in which a beam forming means is improved in order to improve a drawing speed when a repetitive pattern is formed, and a manufacturing method thereof.

[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 form such a pattern by drawing with a charged beam exposure apparatus (usually very fine for the purpose of use), a single figure or a figure group repeatedly used in the same pattern is formed. An exposure method has been proposed in which a pattern is provided in the aperture and a set of patterns is drawn with one shot through the aperture. This exposure method is called, for example, a collective exposure method, a block exposure method, a cell projection method, or a character projection method. Note that, as a typical example of the charged beam, an electron beam (electron beam), a charged particle beam, or an ion beam can be given.

Among the conventional beam exposure methods, the one generally called a point beam method has a round aperture, and the one generally called a variable shaped beam method has a rectangular aperture. Those formed respectively were used, and these were loaded in a charged beam exposure apparatus and exposed. On the other hand, the point that the method such as the collective exposure method (to which the present invention relates) is most different from the conventional beam exposure method lies in the aperture mounted in the charged beam exposure apparatus. In other words, the aperture in the case of this batch exposure method, etc., can be created by creating a single figure repeatedly used for exposure or a figure group consisting of a combination of a plurality of figures in one aperture.
The idea is that these figures or groups of figures are collectively exposed in one shot, and a desired pattern is drawn by this, and this method can dramatically improve the throughput of the exposure process. .

The conventional one of the apertures used in the method such as the one-shot exposure method is prepared by preparing a thick Si substrate 1 as a supporting substrate as shown in FIG. ), A back etching stopper 8 is formed, a Si substrate to be a pattern forming layer is attached thereon as shown in FIG. 3C, and then polished to an appropriate thickness. After forming a masking pattern 9 for back etching from the back side as shown in,
Performs chemical etching according to the crystal orientation of the Si substrate,
Repeatedly used figures and groups of figures are formed in the pattern forming layer as shown in FIG. Here, in some cases, it is constituted by forming a film containing a metal element thereon. Then, for example, when the aperture is loaded in an electron beam writing apparatus and is actually used, a charged beam (an electron beam as a typical example) is irradiated in a region other than the opening of the pattern formation layer. .

[0005]

However, (a) when considering the occurrence of charge-up of the Si substrate at the time of electron beam writing, since the pattern formation layer is made of Si, its conductivity is very high. It can be said that the electric resistance is relatively high. That is, the electrical resistivity of the Si substrate is 2 × 1 at least at room temperature.
It is 0 ¹⁰ μΩ · cm. Therefore, due to the occurrence of charge-up, it may be difficult to accurately transfer and expose the pattern, and in severe cases, the pattern is not transferred at all. (B) Heating at the time of bonding or Si and Si
The stress is generated due to the interposition of the Si oxide film between the and, and the pattern is distorted. (C) By irradiating with an electron beam, the aperture is heated, the pattern is distorted, and in severe cases, the pattern is melted. (D) When trying to solve the problems described in (a) to (d) above, the manufacturing process must be fundamentally changed. The problems described in (a) to (d) above have occurred.

The present invention solves the problems (a) to (d) of the conventional aperture used in the batch exposure method and the like,
Moreover, it is an object of the present invention to provide an aperture and a manufacturing method thereof that can be used for a batch exposure method and the like and can be easily manufactured.

[0007]

Means provided by the present invention in order to solve the above-mentioned problems, namely, a pattern region in which at least a portion through which a charged beam can pass and a portion through which a charged beam cannot pass are selectively formed in a pattern. And a second member supporting the first member, the surface of the first member including the pattern region and the surface of the second member contain a metal element. The aperture is characterized in that a film is formed.

Preferably, the film containing the metal element according to claim 2 is a conductive material, and the aperture according to claim 1.

Further, preferably, the film containing the metal element according to claim 3 has higher conductivity than a main material forming the first member or the second member. 2 is the aperture described in 2.

Further, preferably, the film containing the metal element according to claim 4 has a higher thermal conductivity than the pattern region, and the aperture according to any one of claims 1 to 3. Is.

Further, preferably, the main material used for each part of the film containing the metal element and the pattern region is preferably a wire formed by heat at least in the range of 273K to 373K in absolute temperature. The difference in expansion rate is 5 × 10
^-6 / K or less, the aperture according to any one of claims 1 to 4.

Alternatively, at least according to claim 6,
(A) a step of adhering the material for the first member and the material for the second member, (b) leaving a supporting region in the material for the second member and exposing the material for the first member Etching the material for the member to form the opening of the second member,
(C) A step of selectively forming a pattern in the material for the first member through which a charged beam can pass and a portion where the charged beam cannot pass to obtain a pattern region, and (D) a film containing the metal element on the surface. The method for manufacturing an aperture according to any one of claims 1 to 5, further comprising the steps (a) to (d) of forming.

[0013]

According to the present invention, (i) since a metal having a higher electric conductivity than Si, which is the main material of the aperture, is formed on the entire surface of the formed aperture, electrons are grounded from the film containing the surface metal element. It does not charge up because it flows to. Therefore, distortion of the transfer pattern can be prevented. (Ii) Since a metal having higher thermal conductivity than Si, which is the main material of the aperture, is formed on the entire surface of the produced aperture, heat is radiated from the film containing the surface metal element. Therefore, distortion of the aperture can be prevented. (Iii) Since a metal having a coefficient of linear expansion equivalent to that of Si, which is the main material of the aperture, is formed on the entire surface of the produced aperture, no stress is generated in the aperture. Therefore, distortion of the aperture can be prevented. (Iv) It is not necessary to change the conventional aperture process because only the film containing the metal element is formed on the entire surface of the product formed by the conventional aperture process. The action occurs. Note that the main material forming the first member or the second member is not a Si single crystal, even if it is (wet) etching of the opening on the back surface side as shown in FIG.
As described above, a material having a property that anisotropic etching can be performed and a fine pattern can be favorably formed at the time of forming a pattern on the upper surface is almost the same as that of a Si single crystal, and thus can be suitably used. An example of this is Ga
As single crystal is mentioned.

[0014]

【Example】

<Embodiment> FIG. 1 is a process drawing showing an embodiment of the present invention. First, as shown in FIG. 1A, a supporting substrate 1 having a Si nitride film 4 of 0.5 μm formed on <100> Si having a thickness of 500 μm and a thin Si substrate 2 for a pattern forming layer were prepared. Since this Si substrate 2 is polished to a thickness of 20 μm or less, preferably about 5 to 10 μm in a later step, it is preferable that the thickness is 5 to 10 μm as much as possible so long as it does not cause a problem in work. A thick one was used.

Next, as shown in FIG. 1B, the supporting substrate 1 and the Si substrate 2 are melted and bonded together. Next, as shown in FIG. 1C, the bonded Si substrate 2 portion is polished to a thickness of 15 μm. After that, the opening 3 is formed in the supporting substrate 1. The opening 3 may be larger than the size of the pattern formed on the upper portion, and is 500 in this embodiment.
μm □. At this time, as a method of forming the opening 3, a conventionally known photolithography method was used. That is, the substrate was coated with a resist, exposed by an aligner, developed by the aligner, the Si nitride film 4 was etched by a dry etching apparatus, and the resist was peeled off.

Thereafter, as shown in FIG. 1D, an etching jig 5 is used to etch the opening 3 with the Si nitride film 4 as a mask. At this time, since the etching jig 5 is filled with the heated KOH aqueous solution and the supporting substrate 1 has the plane orientation <100>, the etching is significantly different in the thickness direction from the other directions. Etching proceeds at a very high speed, and finally (practical) etching stop occurs where the Si nitride film 4 is exposed as shown in FIG.

As shown in FIG. 1F, a pattern 6 was formed on the Si substrate 1 opposite to the etched opening 3. At that time, however, the pattern width was widened by the film thickness of the film 7 containing a metal element to be formed in a later step in advance. Here, a conventionally known lithography method is used. That is, an electron beam resist (manufactured by Toray Industries, Inc., trade name: EBR-900) is applied on the Si substrate 2 to a film thickness of about 1 μm, and an electron beam drawing apparatus (manufactured by Hitachi, Ltd., trade name: HL-700). ) To draw the pattern. The line width of the drawing pattern at this time is twice the thickness of the film 7 containing a metal element formed in a later step, that is, 1
It was assumed to be offset by μm.

[0018] Then, after a predetermined development process, a dry etching apparatus (GCA Ltd., trade name: WE616) introducing SF ₆ gas into the chamber at etching is performed of the Si substrate 2, then, SF ₆ gas Instead, C ₂ F ₆ gas was introduced to etch the Si nitride film 4 to remove the resist pattern.

At this stage, the same structure as the conventional aperture was completed. Note that the steps up to this point, that is, the steps of FIGS. 1A to 1E, may be appropriately interchanged before and after. To exemplify a process in which the order is changed, first, the support substrate 1 is prepared, the opening 3 is provided thereon, and then the support substrate 1 and the Si substrate 2 are melted and bonded to each other and polished to an appropriate thickness. Next, a fine pattern may be formed on the Si substrate 2, and the supporting substrate 1 may be etched using the openings 3 formed in the supporting substrate 1 as a mask.

Next, a film containing a metal element is formed on the surface (entire surface in this embodiment) of this aperture. Here, tungsten (W) was used as the material of the film. W has a higher electric conductivity than Si, which is the main material of the aperture here. Electrical resistivity (unit: μΩ ・ c
m), Si is 2 × 10 ¹⁰ , while W is
Is 5.5. (2) High thermal conductivity. Thermal conductivity (unit: cal / cm
In the case of (deg), Si is 0.20, whereas W is 0.39. (3) It has a coefficient of linear expansion equivalent to that of Si. Coefficient of linear expansion (unit:
Dimensionless), while Si is 9.6 × 10 ^-6 ,
W is 4.5 × 10 ⁻⁶ . (Exhibitor: Metal Data Book (Maruzen)).

As shown in FIG. 1 (g), a conventionally known LP
A film made of W was formed on the entire surface of the substrate by using the CVD method. That is, the substrate was placed in a quartz tube of an LPCVD apparatus, WF ₆ gas and SiH ₄ gas were introduced into the apparatus at a ratio of 1: 1 and heated to about 800 ° C. to form a film for several minutes.
At this time, the film thickness of the formed W film was 0.5 μm.

Since the opening of the pattern portion is provided with an offset of 1 μm in advance, it is possible to form a W film by 0.5 μm on both the left and right (or the upper and lower sides) of the boundary of the pattern opening, and the line as designed is designed. Became wide. At this time, as a method for forming the film containing the metal element, another conventionally known method (for example, a plating method) may be used.
Thus, the aperture according to the present invention is completed. When the completed aperture was loaded into an electron beam drawing apparatus and exposure was performed, charge-up did not occur, neither distortion of the substrate nor distortion of the transfer pattern was observed, and good transfer results were obtained.

<Embodiment 2> First, as shown in FIG. 2A, a supporting substrate 1 having a Si nitride film 4 of 0.5 μm formed on a Si substrate of 500 μm thick and having a plane orientation of <100>, A thin Si substrate 2 was prepared for the pattern formation layer. This Si substrate 2 is thinned by polishing to a thickness of 20 μm or less, and preferably about 5 to 10 μm in a later step. From this, the original thickness of the Si substrate 2 is within a range that causes no problem in manufacturing work, and is preferably 5 to 1
It is better to have a thickness close to 0 μm. Therefore, in this example, the Si substrate 2 having a thickness of 100 μm was used.

As shown in FIG. 2B, the supporting substrate 1 and the S
The i substrate 2 is melted and bonded. Next in FIG.
As shown in (c), the bonded Si substrate 2 is polished to a thickness of 15 μm. Then, the opening 3 is formed in the support substrate 1. The opening 3 has only to be larger than the size of the pattern formed above it, and is 500 μm □ in this embodiment. At this time, a conventionally known photolithography method was used as a method for forming the opening 3. That is, the substrate was coated with a resist, exposed using an aligner, the resist was developed, the Si nitride film 4 was etched by a dry etching apparatus, and the resist was peeled off.

After that, as shown in FIG. 2D, an etching jig 5 is used to etch the opening 3 using the Si nitride film 4 as a mask. At this time, the etching jig 5 is filled with the heated KOH aqueous solution, and the supporting substrate 1
Since the plane orientation is <100>, the etching proceeds in the thickness direction, and finally stops at the Si nitride film 4 portion as shown in FIG.

As shown in FIG. 2F, a pattern 6 was formed on the Si substrate 1 on the side opposite to the etched opening 3. At that time, however, the pattern width was widened by the film thickness of the film 7 containing a metal element to be formed in a later step in advance. At this time, a conventionally known lithography method was used. That is, an electron beam resist (manufactured by Toray Industries, Inc., trade name: EBR-900) is formed on the Si substrate 2.
Is applied in a film thickness of about 1 μm, and a pattern is drawn by an electron beam drawing apparatus (Hitachi, Ltd., trade name: H-700). The line width of the drawing pattern at this time was offset by twice the thickness of the film 7 containing a metal element to be formed in a later step, that is, offset by 1 μm.

After the predetermined development processing, S is put in the chamber by a dry etching device (manufactured by GCA, product name: WE616).
The Si substrate 2 is etched by introducing F ₆ gas,
Further, the resist pattern was removed after etching the Si nitride film 4 by introducing C ₂ F ₆ gas. At this stage, an aperture having the same structure as the conventional one is completed. The process up to this point, that is, FIG.
The process of FIG. 2 (e) may be somewhat backward or forward.

Next, the film 7 containing the metal element is formed. In this example, Mo was used. Mo has a higher electrical conductivity than Si, which is the main material of the aperture. Electrical resistivity (unit: μΩ ・ c
m), Si is 2 × 10 ¹⁰ , while M is
o is 5.7. (5) High thermal conductivity. Thermal conductivity (unit: cal / cm
・ Deg) is Mo, while Si is 0.20.
Is 0.34. (6) It has a coefficient of linear expansion equivalent to that of Si. Coefficient of linear expansion (unit:
Dimensionless), while Si is 9.6 × 10 ^-6 ,
Mo is 5.1 × 10 ⁻⁶ . (Exhibitor: Metal Data Book (Maruzen)).

As shown in FIG. 2 (g), a Mo film was formed on the entire surface of the aperture substrate in the process of formation by a conventionally known plating method. Here, the composition of the plating solution was: molybdenum trioxide 36 g / l, potassium hydroxide 430 g / l, ammonia water (28%) 400 ml, formic acid (87%) 540 ml, and the pH of the plating bath was 5.8. The plating was performed for several minutes under the conditions of a temperature of 35 ° C. and a current density of 50 A / dm ² . At this time, the film thickness of the formed Mo film was 0.5 μm.

Since the pattern opening has an offset of 1 μm in advance, it is possible to form a Mo film by 0.5 μm on both the left and right (or the top and bottom) of the boundary of the pattern opening, and the line according to the design dimension can be formed. Became wide. At this time, as a method for forming the film containing the metal element, another conventionally known method (for example, CVD method) may be used. This completes the aperture according to the present invention. In addition, when the electron beam drawing apparatus was loaded with the aperture and drawing was performed,
No charge-up occurred, no substrate distortion or transfer pattern distortion was observed, and good transfer results were obtained.

[0031]

According to the present invention, when the aperture is loaded in a charged beam exposure apparatus and exposed, a substance having a high thermal conductivity is provided, so that the aperture diaphragm is deformed and melted by heat. The effect that is not generated was obtained. Further, when the charged beam exposure apparatus is loaded with the aperture and exposed, since the film containing the metal element has a linear expansion coefficient equivalent to that of Si which is a main material, the distortion of the aperture is reduced. The effect is that it does not occur (in practice, it can be considered that there is no distortion). Further, when the aperture is loaded in the charged beam exposure apparatus and exposure is performed, the effect that the charge-up does not occur because the film containing the metal element has conductivity. Moreover, no major changes in the manufacturing process were necessary to achieve the above effects. In general, (above) (b) When considering the occurrence of charge-up of the Si substrate during electron beam writing, the pattern forming layer is made of Si, so that the conductivity is not very high. Rather, it can be said that the electrical resistivity is relatively high. That is, the electrical resistivity of the Si substrate is 2 × 1 at least at room temperature.
It is 0 ¹⁰ μΩ · cm. Therefore, due to the occurrence of charge-up, it may be difficult to accurately transfer and expose the pattern, and in severe cases, the pattern is not transferred at all. (B) Heating at the time of bonding or Si and Si
The stress is generated due to the interposition of the Si oxide film between the and, and the pattern is distorted. (C) By irradiating with an electron beam, the aperture is heated, the pattern is distorted, and in severe cases, the pattern is melted. (D) When trying to solve the problems described in (a) to (d) above, the manufacturing process must be fundamentally changed. As described above, it is possible to provide the aperture and the manufacturing method thereof, which can solve the problems described in (a) to (d), and can be used in the batch exposure method and the like and can be easily manufactured. It was

[Brief description of drawings]

FIG. 1 is an explanatory view showing an outline of a manufacturing process of an embodiment of an aperture and a manufacturing method thereof according to the present invention by using a sectional view.

FIG. 2 is an explanatory view showing the outline of a manufacturing process of another embodiment of the aperture and the manufacturing method thereof according to the present invention, using a sectional view.

FIG. 3 is an explanatory diagram showing an outline of a manufacturing process of an example of a conventional art aperture and a manufacturing method thereof with reference to sectional views.

[Explanation of symbols]

 1 ... Support substrate 2 ... Si substrate 3 ... Opening portion 4 ... Si nitride film 5 ... Etching jig 6 ... Pattern 7 ... Metal element-containing film 8 ....・ Back etching stopper 9 ... Masking pattern

Claims (6)

[Claims] 1. A first member having at least a pattern region in which a portion through which a charged beam can pass and a portion through which a charged beam cannot pass are selectively formed in a pattern, and a second member supporting the first member. The aperture is characterized in that a film containing a metal element is formed on the surface of the first member including the pattern region and the surface of the second member. 2. The aperture according to claim 1, wherein the film containing the metal element is a conductive material. 3. The aperture according to claim 1, wherein the film containing the metal element has higher conductivity than a main material forming the first member or the second member. 4. The film containing the metal element has a thermal conductivity higher than that of the pattern region.
4. The aperture according to any one of 3 to 3. Wherein said main materials used for each portion of the metal elements and film containing said pattern region, the difference in linear expansion coefficient caused by heat in the range of 373K at least the absolute temperature 273K is 5 × 10 ^- The aperture according to any one of claims 1 to 4, which is ⁶ / K or less. 6. At least (a) the step of adhering the material for the first member and the material for the second member, (b) leaving the supporting region in the material for the second member, and for the first member A step of etching the second member material until the material is exposed to form an opening of the second member, and (c) a portion through which the charged beam can pass and a portion through which the charged beam cannot pass are selectively formed in the first member material. A step of forming a pattern region by patterning on the surface, (d) a step of forming a film containing the metal element on the surface, or above (a)
The method for manufacturing an aperture according to any one of claims 1 to 5, further comprising: