JP2001235873A - Method for forming tapered shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for forming a high-accuracy tapered shape using only the photolithography method. SOLUTION: The method for forming the three-dimensional tapered shape on a substrate 1 having a photosensitive layer 3 has a first step of forming an antireflection film 2 between the substrate and the photosensitive layer, a second step of exposing the photosensitive layer by rays 5 inclined in optical axis with respect to the substrate and a third step of obtaining the tapered shape by removing either of the exposed segment 3a or non-exposed segment 3b of the photosensitive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a tapered shape used in a three-dimensional micropart such as an optical integrated circuit, and more particularly to a method for obliquely exposing a photosensitive layer and suppressing exposure due to a reflected wave from a substrate. And a method for forming a tapered shape with improved accuracy.

[0002]

2. Description of the Related Art FIGS. 6A to 6G are side sectional views showing stepwise (a) to (g) steps of a conventional method of forming a tapered shape disclosed in Japanese Patent Application Laid-Open No. 6-21039.

In FIG. 6, reference numeral 10 denotes a semiconductor substrate (hereinafter, referred to as a semiconductor substrate).
11 is a thermal oxide film made of SiO ₂ formed on the substrate 10, and 12 and 13 are thermal oxide films 11
The first, consisting of SiON (optical waveguide layer) formed on
The second thin film layer 15 is a mask made of a photoresist layer disposed on the second thin film layer 13.

In FIG. 6G, reference numeral 16 denotes an optical waveguide layer formed on the first thin film layer 12,
After the removal of 3, the first thin film layer 12 is formed following the tapered shape. The refractive index of the optical waveguide layer 16 is set smaller than the refractive index at the tapered portion of the first thin film layer 12. Reference numeral 17 denotes a guided light, which is coupled from the optical waveguide layer 16 to the first thin film layer 12.

Hereinafter, a conventional method for forming a tapered shape will be specifically described with reference to FIGS. 6 (a) to 6 (g). First, as shown in FIG. 6A, first and second thin film layers 12 and 13 etched with the same etching solution are formed on a substrate 10 on which a thermal oxide film 11 has been formed. A mask 15 is formed on the layer 13.

At this time, the first and second thin film layers 12 and 13
Of the first and second thin film layers 12 and 1 so that the etch rate with respect to the etching solution becomes higher toward the upper layer side.
The layers are stacked in the order of 3.

Next, using the mask 15, the second thin film layer 13 and the first thin film layer 12 are selectively etched by an etching solution to form a tapered shape as shown in FIGS. To form

In the formation of the tapered thin film at this time, the etching with the etching solution and the subsequent rinsing step are repeated a plurality of times, whereby the second thin film layer 13 and the first thin film layer 12 are selectively formed. Etched.

Next, as shown in FIG. 6F, after removing the mask 15, the second thin film layer 13 is removed with a hydrofluoric acid-based solution or the like. At this time, since the etching rate of the second thin film layer 13 is much higher than the etching rate of the first thin film layer 12, the first thin film layer 12 does not change.

Finally, as shown in FIG. 6G, another optical waveguide layer 16 is formed on the first thin film layer 12 by a CVD method, a sputtering method, a vapor deposition method, a plasma CVD method, or the like. The guided light 17 incident on the end face of the optical waveguide layer 16 from the left side in the figure is coupled to the first thin film layer 12 having a larger refractive index than the optical waveguide layer 16 at the tapered portion.

[0011]

As described above, the conventional method of forming a tapered shape involves performing etching with an etching solution and a subsequent rinsing step a plurality of times (FIG. 6B).
(See (e)) The taper shape is formed by repeating.

Therefore, in order to obtain a desired tapered shape, it is necessary to set conditions for the etching rates of the plurality of thin film layers 12 and 13, and the number of process steps becomes extremely large, and a large taper angle is realized. Therefore, there is a problem that the accuracy of the tapered shape cannot be improved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a method of forming a tapered shape capable of forming a desired tapered shape with high accuracy using only photolithography. The purpose is to:

[0014]

According to a first aspect of the present invention, there is provided a method for forming a tapered shape on a substrate having a photosensitive layer.
In a method of forming a three-dimensional tapered shape, a first step of forming an anti-reflection film between a substrate and a photosensitive layer, and an optical axis inclined with respect to the substrate via a mask having a light blocking portion. The method includes a second step of exposing the photosensitive layer with a light beam, and a third step of removing one of an exposed portion and a non-exposed portion of the photosensitive layer to obtain a tapered shape.

According to a second aspect of the present invention, there is provided a method for forming a tapered shape according to the first aspect, wherein the antireflection film is formed by a film having a surface roughness of polyimide or metal increased. .

According to a third aspect of the present invention, in the method for forming a tapered shape according to the first aspect, the antireflection film is formed by a film that absorbs light.

According to a fourth aspect of the present invention, in the method for forming a tapered shape according to the third aspect, the antireflection film has a thickness that does not allow the reflected light from the substrate to reach the photosensitive layer. .

According to a fifth aspect of the present invention, there is provided a tapered shape forming method according to the first aspect, wherein the antireflection film is formed of a film having a refractive index larger than that of the photosensitive layer.

According to a sixth aspect of the present invention, in the method for forming a tapered shape according to any one of the first to fifth aspects, the second step includes changing an inclination angle of the optical axis with respect to the substrate. The method includes a fourth step of multiple exposure of the photosensitive layer.

According to a seventh aspect of the present invention, in the method for forming a tapered shape according to any one of the first to sixth aspects, the second step includes rotating the substrate to form a tapered rotator. Is formed.

According to a eighth aspect of the present invention, there is provided a method for forming a tapered shape according to any one of the first to seventh aspects, wherein the tapered shape obtained in the third step is used as a transfer mold. Then, the method includes a sixth step of forming a transferred material on the tapered portion, and a seventh step of removing the remaining portion of the photosensitive layer having the tapered shape.

According to a ninth aspect of the present invention, in the method for forming a tapered shape according to the ninth aspect, the first step includes an eighth step of forming a conductive film on the upper surface of the antireflection film as an electrode layer. Including.

According to a tenth aspect of the present invention, in the ninth aspect, the electrode layer is made of copper deposited on the upper surface of the antireflection film, and the transferred material is formed by electroplating. It is composed of the formed copper.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. 1A and 1B are views for explaining a method of forming a tapered shape according to Embodiment 1 of the present invention. FIG. 1A is a side sectional view showing a state at the time of exposure, and FIG. It is a sectional side view which shows the taper shape after forming by development of a).

In FIG. 1, 1 is a substrate made of, for example, Si, and 2 is an antireflection film formed on the substrate 1.
The surface of the anti-reflection film 2 is, for example, a surface of polyimide set to an appropriate roughness by a sandblaster, and is configured not to reflect incident light.

Reference numeral 3 denotes a photosensitive layer formed on the anti-reflection film 2, for example, a negative resist (EPON manufactured by IBM).
SU-8). 3a is an exposed portion of the photosensitive layer 3, and 3b is a non-exposed portion of the photosensitive layer 3.

Reference numeral 4 denotes a glass mask having a desired shape drawn with Cr, for example, 4a denotes a light transmitting portion of the glass mask 4, and 4b denotes a light blocking portion (Cr portion) of the glass mask 4.

Reference numeral 5 denotes a light beam for exposing the photosensitive layer 3, which is emitted from, for example, a light source (not shown) such as a mercury lamp, and further converted into parallel light.

Next, a first embodiment of the present invention will be specifically described with reference to FIG. First, as a first step, an antireflection film 2 is formed between the substrate 1 and the photosensitive layer 3.

Next, as a second step, FIG.
As shown in (a), the substrate 1 is arranged obliquely with respect to the optical axis of the light beam 5, and exposure is performed at a desired angle θ via a glass mask 4 having a light blocking portion 4b. In addition,
Although not shown here, a known positioning mechanism is used to set the inclination angle θ of the substrate 1.

Finally, as a third step, the photosensitive layer 3
Is removed to form a tapered shape. That is, the non-exposed portion 3 of the photosensitive layer 3 made of a negative resist
b is removed by developing with a developing solution, and as shown in FIG. 1B, a tapered shape having an inclination angle θ is formed in the exposed portion 3a of the photosensitive layer 3.

As described above, the substrate 1 on which the photosensitive layer 3 (negative resist) is formed is exposed to light obliquely with respect to the optical axis of the light beam 5, and after the photosensitive layer 3 is exposed, the photosensitive layer 3 is developed. Thus, a tapered shape can be easily obtained. Therefore, a large number of substrates 1 having a desired tapered shape can be manufactured at low cost.

Further, by forming the anti-reflection film 2 between the substrate 1 and the photosensitive layer 3, the reflection wave from the substrate 1 is reduced via the anti-reflection film 2 at the time of the exposure for forming the tapered shape. Therefore, exposure due to reflected waves can be prevented, and a more precise tapered shape can be formed.

Therefore, a desired tapered shape can be formed only by using the photolithography method. Although FIG. 1 shows only one tapered shape of a pattern, the same pattern can be formed even if there are two or more patterns.

Although the substrate 1 is made of Si, it is not limited to Si, but may be made of alumina, glass, copper or the like, and it goes without saying that the same operation and effect as described above can be obtained.

As the anti-reflection film 2, a polyimide surface having a suitable surface roughness using a sand blaster or the like is used. However, the present invention is not limited to the sand blaster. It may be configured to have an appropriate surface roughness.

Further, although polyimide made of resin is used as the antireflection film 2, it is not limited to polyimide. For example, the surface of a metal may be formed to have an appropriate surface roughness. An effect can be obtained.

Further, although a negative resist was used as the photosensitive layer 3, the present invention is not limited to the negative resist, and the same effect can be obtained by using a positive resist. In this case, the exposed portion 3a, not the non-exposed portion 3b, is removed by the resist.

Embodiment 2 In the first embodiment, as shown in FIG. 1, a taper shape having a parallel inclination angle θ is formed on both sides by one exposure, but a plurality of (eg, two) exposures Any tapered shape may be formed.

FIG. 2 is a side sectional view for explaining a second embodiment of the present invention in which a trapezoidal cross section is formed by two exposures, and shows a state after the taper is formed.

In FIG. 2, 1-3, 3a, and θ are the same as those described above (see FIG. 1), and the exposure steps not shown in FIG. 2 are the same as those in the method shown in FIG. .

In this case, in the exposed portion 3 a of the photosensitive layer 3, the direction of inclination of the substrate 1 is reversed, and two exposures are performed at the respective inclination angles θ in the opposite directions, whereby a symmetrical inclination angle is obtained. A tapered section having a trapezoidal cross section having θ is formed.

Next, a second embodiment of the present invention will be specifically described with reference to FIGS. First, FIG.
As in (a), the substrate 1 is set at a predetermined angle θ with respect to the light beam 5.
After the exposure, the direction of inclination of the substrate 1 is changed to the opposite (symmetric direction), and the exposure is similarly performed at the inclination angle θ. Thereby, the cross-sectional shape of the non-exposed portion 3b becomes a trapezoidal tapered shape.

After the two exposures are performed in this way, the non-exposed portion 3b is developed by developing with a developing solution as described above.
Is removed. Therefore, as shown in FIG. 2, the exposed portion 3a forms a tapered shape having a symmetrical inclination angle θ.

As described above, a taper shape having a symmetrical inclination angle θ can be obtained only by developing the resist after the resist is multiplexed (doubled) by inclining the substrate 1 with respect to the light beam 5. The substrate 1 having a desired tapered shape can be manufactured in large quantities at low cost.

As described above, the number of the tapered patterns can be arbitrarily formed, and the substrate 1, the antireflection film 2 and the photosensitive layer 3 can be formed arbitrarily.

Embodiment 3 In the second embodiment, a trapezoidal tapered groove is formed by double exposure.
When double exposure is used, not only a trapezoidal tapered groove but also various tapered shapes can be formed. For example, a tapered groove having a V-shaped cross section may be formed.

That is, in the exposure step (second step), the photosensitive layer 3 is subjected to multiple exposure by arbitrarily changing the inclination angle θ of the substrate 1 with respect to the optical axis, so that not only a symmetric taper shape but also an arbitrary A tapered shape having an inclination angle can be formed.

FIG. 3 is a side sectional view for explaining a third embodiment of the present invention in which a tapered groove having a V-shaped cross section is formed, and shows a substrate state in an exposure step for forming a taper. . In FIG. 3, 1-4 and θ are as described above (FIG. 1).
Reference).

In this case, the antireflection film 2 is formed of the same negative resist as that of the photosensitive layer 3 and is applied onto the substrate 1 at the same time as the photosensitive layer 3. Anti-reflection film 2
Is formed of a layer having a light absorbing property for a reflected wave, and has a thickness that does not allow the reflected light from the substrate 1 to reach the photosensitive layer 3.

The width of the light blocking portion 4b of the glass mask 4 is set shorter than that described above (see FIG. 1). When the exposure is performed twice by reversing the tilt direction of the substrate 1, In relation to the magnitude of the inclination angle θ and the thickness of the photosensitive layer 3, the end of the inverted optical path of the light ray 5 (see FIG. 1) is made to coincide on the surface of the antireflection film 2.

Therefore, when the substrate 1 is exposed to the light beam 5 at a predetermined angle θ, and then the substrate 1 is changed to a reverse (symmetrical) angle θ, the non-exposed portion 3 is exposed.
The cross-sectional shape of b is a V-shaped tapered shape as shown in FIG.

The light beam incident on the anti-reflection film 2 is
The reflection is prevented at the boundary surface with the substrate 1 (see the broken line in FIG. 3). Thereafter, the negative resist in the non-exposed portion 3b is removed by developing with a developer in the same manner as described above, and a tapered shape having a V-shaped cross section is formed as shown in FIG.

Also in this case, since the antireflection film 2 does not allow the light reflected from the substrate 1 to reach the photosensitive layer 3, it is possible to prevent the exposure by the reflected wave from the substrate and to form a more precise tapered shape.

Here, the antireflection film 2 and the photosensitive layer 3 are applied at once using the same material, but different types of resists may be applied separately.
Further, the same effect can be obtained even if the antireflection film 2 and the photosensitive layer 3 are not limited to a negative resist but are also a positive resist.

Embodiment 4 In the third embodiment, the antireflection film 2 is formed of the light absorbing layer. However, the refractive index of the antireflection film 2 may be set to be larger than the refractive index of the photosensitive layer 3.

In this case, the reflected wave from the substrate 1 is suppressed from entering the photosensitive layer 3 from the anti-reflection film 2 at the boundary between the anti-reflection film 2 and the photosensitive layer 3, so that the exposure by the reflected light can be performed. Thus, a more precise tapered shape can be formed.

Embodiment 5 FIG. Further, in the second embodiment, the non-exposed portion 3b is formed to have a trapezoidal cross section, but the exposed portion 3a may be formed to have a trapezoidal cross section. Further, by rotating the substrate 1 during the exposure, the exposed portion 3a may have a truncated cone shape.

FIGS. 4 (a) and 4 (b) are a side sectional view and a perspective view for explaining a fifth embodiment of the present invention in which the exposed portion 3a has a truncated cone shape, and FIG. FIG. 3B shows the tapered shape after development. In FIG. 4, 1 to 4 and θ are the same as described above.

In this case, the light beam 5 from the light source (see FIG. 1)
, The substrate 1 is inclined at a predetermined angle θ, and
Is exposed while rotating, and then developed with a developer. Thereby, the negative resist in the non-exposed portion 3b is removed, and a truncated cone-shaped projection shown in FIG. 4B is formed.

As described above, the substrate 1 is rotated obliquely with respect to the light source, and the resist is exposed to light and then developed, thereby forming a truncated cone having a tapered portion (rotator).
(Exposed portion 3a) can be manufactured in large quantities at low cost.

In the fifth embodiment, the anti-reflection film 2 is formed of a light absorbing layer. However, as described above, polyimide or metal having a large surface roughness may be used. Films having different rates may be used.

In the exposure step (during the rotation of the substrate 1), the inclination angle θ between the photosensitive layer 3 and the light beam 5 and the light blocking portion 4
The shape of b can be set arbitrarily, whereby
A rotating body having an arbitrary tapered shape can be formed.

For example, the light shielding portion 4 of the glass mask 4
By changing the shape of b, a truncated cone (or cone) pattern of any shape can be formed. Further, in FIG. 4, only one pattern is formed on the substrate 1, but a large number of patterns may be formed at the same time.

Embodiment 6 FIG. It should be noted that the first to the first embodiments
In No. 5, no additional processing was performed after removing the unexposed portion 3b of the photosensitive layer 3, but the exposed portion 3a of the photosensitive layer 3 may be removed after injecting a transcript by, for example, metal plating.

FIG. 5 shows a sixth embodiment of the present invention in which a transferred product is formed using the tapered shape after removing the resist as a mold.
FIG. 5 is a side cross-sectional view for explaining a state before a tapered shape is formed by a transferred material.

In FIG. 5, 1 to 3 and θ are the same as described above. In this case, the non-exposed portion (removed portion) has a trapezoidal cross section in which the light beam 5 incident side is narrow.

Reference numeral 6 denotes an electrode layer made of, for example, copper, which is formed on the upper surface of the antireflection film 2 by vapor deposition at the boundary between the antireflection film 2 and the photosensitive layer 3. Numeral 7 denotes a tapered transfer material made of, for example, copper, which is formed by plating on the electrode layer 6 after removing the non-exposed portion 3b.

In this case, the first step includes a step of depositing copper on the upper surface of the antireflection film 2 to form the electrode layer 6, and the electrode layer 6 is formed on the antireflection film 2. Filmed.

Subsequently, after the photosensitive layer 3 is applied on the electrode layer 6, the same exposure processing as described above is performed. At this time, if the surface roughness of the antireflection film 2 is large, the electrode layer 6 deposited on the antireflection film 2 also has a large surface roughness.
In the subsequent exposure step, the function as the antireflection film 2 is not impaired.

That is, by exposing the substrate 1 to the optical axis of the light beam 5 in a state where the substrate 1 is obliquely inclined at a desired angle θ, subsequently inverting the direction of the inclination and exposing, and then developing with a developing solution, The negative resist in the non-exposed portion 3b is removed to form a tapered shape having an inclination angle θ.

Thereafter, the removed portion of the non-exposed portion 3b is plated with copper by electroplating, as shown in FIG.
For example, a transfer material 7 having a tapered shape made of copper is formed.
Finally, by removing the remaining portion (exposed portion 3a) of the photosensitive layer 3 having the tapered shape, a tapered shape composed of the transferred material 7 is formed on the substrate 1.

Therefore, it is possible to form a tapered shape composed of the transferred material 7 on the substrate 1, and to form an arbitrary tapered shape even when the electrode layer 6 is provided. Can be applied to applications.

At this time, when the electrode layer 6 is formed by copper vapor deposition as shown in FIG. 5, the transfer 7 made of copper plating is electrically and mechanically connected to the electrode layer 6 integrally. It is also firmly formed integrally with the substrate 1.

As a result, the tapered shape of the photosensitive layer 3 (the portion where the non-exposed portion 3b is removed) is used as a mold for forming the transferred material 7, and the tapered shape of the photosensitive layer 3 is transferred to the transferred material 7. Can be.

As described above, by simply exposing the photosensitive layer 3 (resist) by obliquely tilting the substrate 1 with respect to the light source, and then developing and plating, it is possible to easily obtain the transfer product 7 having an arbitrary shape. Therefore, the tapered shape can be manufactured in large quantities and at low cost.

In the sixth embodiment, copper is deposited as the electrode layer 6 on the antireflection film 2. However, the electrode layer 6 may be made of another metal or conductive film. May be formed on the antireflection film 2 by the above method.

Further, in FIG. 5, only one pattern is shown as the tapered shape of the transferred material 7, but it is needless to say that two or more patterns can be formed as described above.

[0079]

As described above, according to the first aspect of the present invention, in a method for forming a three-dimensional tapered shape on a substrate having a photosensitive layer, an antireflection film is formed between the substrate and the photosensitive layer. A second step of exposing the photosensitive layer with a light beam whose optical axis is inclined with respect to the substrate through a mask having a light blocking part; and exposing the exposed or unexposed part of the photosensitive layer. 3rd to remove one to obtain tapered shape
And a step of forming a tapered shape capable of forming a desired tapered shape with high accuracy by using only the photolithography method.

According to a second aspect of the present invention, in the first aspect, the antireflection film is formed by a film having a large surface roughness of the surface of polyimide or metal. Thus, there is an effect that a method of forming a tapered shape that can form a desired tapered shape with high accuracy is obtained.

According to a third aspect of the present invention, in the first aspect, the anti-reflection film is formed of a film that absorbs light. There is an effect that a method for forming a tapered shape that can be formed with high accuracy is obtained.

According to a fourth aspect of the present invention, in the third aspect, the antireflection film has a thickness that does not allow the reflected light from the substrate to reach the photosensitive layer. Thus, there is an effect that a method of forming a tapered shape that can form a desired tapered shape with high accuracy is obtained.

According to a fifth aspect of the present invention, in the first aspect, the anti-reflection film is formed by a film having a refractive index larger than that of the photosensitive layer. There is an effect that a method for forming a tapered shape that can form the tapered shape with high precision can be obtained.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the second step comprises changing the angle of inclination of the optical axis with respect to the substrate to multiple exposure of the photosensitive layer. Since the method includes the fourth step, a desired taper shape can be formed with high accuracy using only the photolithography method, and a method of forming a taper shape capable of easily realizing various taper shapes can be obtained. .

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the second step is the fifth step of forming a tapered rotator by rotating the substrate. In addition to the steps described above, there is an effect that a desired tapered shape can be formed with high accuracy using only the photolithography method, and a tapered shape forming method capable of easily realizing various tapered shapes can be obtained.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the tapered shape obtained in the third step is used as a transfer mold to form the tapered shape. Since the method includes a sixth step of forming a transfer material on a portion and a seventh step of removing the remaining portion of the photosensitive layer having the tapered shape, the desired tapered shape is formed only by photolithography. In addition to the high-precision formation, there is an effect that a method of forming a taper shape capable of easily realizing various taper shapes is obtained.

According to a ninth aspect of the present invention, in the eighth aspect, the first step includes the eighth step of forming a conductive film as an electrode layer on the upper surface of the antireflection film, so that photolithography is performed. By using only the method, a desired tapered shape can be formed with high precision, and a method of forming a tapered shape applicable to various uses can be obtained.

According to a tenth aspect of the present invention, in the ninth aspect, the electrode layer is made of copper deposited on the upper surface of the antireflection film, and the transferred material is made of copper formed by electroplating. With such a configuration, there is an effect that a desired tapered shape can be formed with high precision using only the photolithography method, and a tapered shape forming method applicable to various uses can be obtained.

[Brief description of the drawings]

FIGS. 1A and 1B are side sectional views for explaining Embodiment 1 of the present invention, in which FIG. 1A shows an exposed state, and FIG. 1B shows a tapered shape after removing a resist.

FIG. 2 is a side sectional view showing a tapered shape formed according to a second embodiment of the present invention.

FIG. 3 is a side sectional view for explaining Embodiment 3 of the present invention, showing an optical path in a photosensitive layer at the time of exposure.

FIGS. 4A and 4B are views for explaining Embodiment 5 of the present invention, wherein FIG. 4A is a side sectional view showing an optical path in a photosensitive layer at the time, and FIG. FIG.

FIG. 5 is a side sectional view for describing Embodiment 6 of the present invention, and shows a state in which a transferred material is formed in a tapered mold.

FIG. 6 is a side sectional view showing stepwise a conventional method of forming a tapered shape.

[Explanation of symbols]

Reference Signs List 1 substrate, 2 antireflection film, 3 photosensitive layer, 3a exposed portion, 3b unexposed portion, 4 glass mask, 4a light transmitting portion, 4b light blocking portion, 5 light beams, 6 electrode layers, 7
Transcript, θ tilt angle.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) H01L 21/027 H01L 21/30 514C 574 576 (72) Inventor Sai Ota 2-chome Marunouchi 2-chome, Chiyoda-ku, Tokyo No. 3 Mitsubishi Electric Corporation F-term (reference) 2H025 AB14 AB17 AB20 AC01 AD01 BC13 BC31 DA34 DA40 FA03 FA04 FA39 2H096 AA28 AA30 BA01 CA05 EA12 EA30 2H097 BB03 CA13 LA10 4K024 AA09 AB08 BA09 BB12 FA05 GA16 5F046 CB25 PA07

Claims (10)

[Claims] 1. A method for forming a three-dimensional tapered shape on a substrate having a photosensitive layer, comprising: a first step of forming an antireflection film between the substrate and the photosensitive layer; and a light blocking portion. A second step of exposing the photosensitive layer with a light beam having an optical axis inclined with respect to the substrate through a mask;
And a third step of removing one of an exposed portion and a non-exposed portion of the photosensitive layer to obtain a tapered shape. 2. The method according to claim 1, wherein the antireflection film is formed of a film having a surface roughness of polyimide or metal. 3. The method according to claim 1, wherein the antireflection film is formed of a light absorbing film. 4. The method according to claim 3, wherein the antireflection film has a thickness that does not allow light reflected from the substrate to reach the photosensitive layer. 5. The method according to claim 1, wherein the antireflection film is formed of a film having a higher refractive index than the photosensitive layer. 6. The method according to claim 1, wherein the second step includes a fourth step of changing a tilt angle of the optical axis with respect to the substrate and performing multiple exposure of the photosensitive layer. The method for forming a tapered shape according to any one of the above. 7. The method according to claim 1, wherein the second step includes a fifth step of forming a tapered rotator by rotating the substrate. A method for forming the tapered shape described above. 8. The method according to claim 6, wherein the tapered shape obtained in the third step is used as a transfer die, and a sixth step of forming a transferred material on the tapered portion, and the tapered shape is formed. Removing the remaining portion of the photosensitive layer.
The method of forming a tapered shape according to any one of claims 1 to 7, comprising the following steps: 9. The method according to claim 8, wherein the first step includes an eighth step of forming a conductive film on the upper surface of the antireflection film as an electrode layer. 10. The method according to claim 9, wherein the electrode layer is made of copper deposited on an upper surface of the anti-reflection film, and the transferred material is made of copper formed by electroplating. A method for forming the tapered shape described above.