JP5475524B2 - Resist sensitivity curve creation method, fine shape manufacturing method, and fine shape manufacturing apparatus - Google Patents

Description

  The present invention relates to setting of the amount of laser light irradiated to a photosensitive resin when a photosensitive resin is irradiated with laser light to obtain a fine shape, and more particularly to a resist sensitivity curve used for setting the amount of laser light.

Conventionally, a fine shape (fine pattern) has been formed by laser drawing in which a photosensitive resin is irradiated with laser light.
In the case of forming a fine shape by laser drawing, an exposure amount for obtaining a target pattern height is calculated using a resist sensitivity curve, and the calculated exposure amount is set in the laser drawing apparatus. The resist sensitivity curve expresses the relationship between the exposure amount and the resist removal amount after development. The relationship between the exposure amount and the resist removal amount is obtained by exposing the photosensitive resin using a predetermined exposure amount and measuring the resist residual film value after development. The predetermined exposure amount ranges from zero to the remaining film of the photosensitive resin after development becomes zero, and a resist removal amount corresponding to the exposure amount is obtained using a plurality of exposure amounts within the range. To do. However, the exposure amount is calculated using the resist sensitivity curve, and there is a deviation between the shape actually formed using the calculated exposure amount and the target shape (desired shape). This shift becomes a problem particularly when a fine shape is formed.

  For example, Patent Document 1 discloses a method for correcting the exposure amount by exposing a test pattern having a similar shape in advance and obtaining a shape difference between the target shape and the test pattern in order to eliminate this deviation. ing.

JP 2005-49460 A

However, in the method of Patent Document 1, it is necessary to expose a test pattern in advance. That is, when modeling a desired fine shape, it was necessary to perform exposure at least twice. For this reason, time and cost were to be increased.
In general, a resist sensitivity curve is a resist removal amount when a resist is exposed and developed, and is only a physical property value of the resist material itself. When forming a fine shape by the laser drawing method, it is preferable to use a resist sensitivity curve obtained by a method suitable for laser drawing, but such a resist sensitivity curve does not exist. For this reason, the error between the actually obtained shape and the desired shape is large.

  Therefore, an object of the present invention is to provide a method for creating a resist sensitivity curve suitable for laser drawing, a method for obtaining a fine shape using the resist sensitivity curve, and an apparatus.

  One aspect of a method for creating a resist sensitivity curve according to the present invention is a method for creating a resist sensitivity curve used in manufacturing a fine shape by irradiating a photosensitive resin with laser light to obtain a fine shape. In the resist sensitivity curve, (1) a test region in which a plurality of sensitivity measurement regions are adjacent to each other is set in the photosensitive resin, and (2) the amount of laser light is set so that the light amount differs for each of the plurality of sensitivity measurement regions It is created by each step of obtaining a resist sensitivity curve using a test area obtained by modulating and exposing, and (3) developing a photosensitive resin. By the method described above, a resist sensitivity curve suitable for laser description is obtained. That is, it is possible to obtain a resist sensitivity curve in consideration of the influence of laser light irradiation in adjacent irradiation regions.

  In one aspect of the method for creating a resist sensitivity curve according to the present invention, the sensitivity measurement region is rectangular, and the width of the rectangle is preferably 0.5 to 1.4 times the laser spot diameter. Twice is preferred. The width of the rectangle is preferably larger than the diameter of the laser spot. For example, when the diameter of the laser spot is 1 μm, the width of the sensitivity measurement region is preferably 1.2 μm. By determining the sensitivity measurement region in accordance with the diameter of the laser spot, the influence of the laser light applied to the adjacent sensitivity measurement region is appropriately reflected.

  In one aspect of the method for creating a resist sensitivity curve according to the present invention, the amount of laser light is preferably modulated stepwise for each of a plurality of sensitivity measurement regions. By using the change in the light amount of the laser light according to the state of manufacture of the fine shape, the influence of the laser light irradiated on the adjacent sensitivity measurement region is appropriately reflected.

  Moreover, it is preferable to acquire a resist sensitivity curve according to the kind of photosensitive resin, or according to the film thickness of the photosensitive resin. The amount of laser light and the resist removal amount differ depending on the type or film thickness of the photosensitive resin. For this reason, it is preferable to use the resist sensitivity curve according to the kind of photosensitive resin which manufactures a fine shape, or a film thickness.

  One aspect of the method for producing a fine shape according to the present invention is a production method for obtaining a fine shape by irradiating the photosensitive resin 12 with a laser beam. (1) A coating step of applying a photosensitive resin to a substrate; ) A light amount setting step for setting the light amount of the laser light applied to the photosensitive resin; (3) an exposure step for scanning the photosensitive resin while modulating the light amount of the laser light according to the set light amount; and (4). A developing step for developing the exposed substrate. In the light amount setting step, the light amount is set using a resist sensitivity curve and a fine shape acquired in advance. In the resist sensitivity curve, a test region in which a plurality of sensitivity measurement regions are adjacent to each other is set on the photosensitive resin 12, and scanning is performed while modulating the light amount of the laser light so that the light amount differs for each of the plurality of sensitivity measurement regions. Get. By using this resist sensitivity curve, the amount of laser light is determined in consideration of the effects of laser light irradiation in adjacent irradiation regions in a fine-shaped manufacturing method that irradiates laser light for each arbitrary irradiation region. Can do.

  ADVANTAGE OF THE INVENTION According to this invention, the method of creating the resist sensitivity curve suitable for laser drawing can be provided. In addition, a method and an apparatus for manufacturing a fine shape using the resist sensitivity curve can be provided.

It is a block diagram which shows the outline of the structural example of the manufacturing apparatus which models the fine shape which concerns on Embodiment 1 of this invention. It is a figure which shows the setting state of the test area | region of an Example. It is a figure which shows the change of the light quantity of the laser beam of an Example and a comparative example. It is a figure which shows the resist sensitivity curve obtained in the Example. It is a figure which shows a difference with the fine shape and design shape which were obtained in the Example. It is a figure which shows the setting state of the test area | region of a comparative example. It is a figure which shows the resist sensitivity curve obtained by the comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In the drawings, components having the same configuration or function and corresponding parts are denoted by the same reference numerals and description thereof is omitted.

Embodiment 1
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing an outline of a configuration example of a manufacturing apparatus for modeling a fine shape according to Embodiment 1 of the present invention.
The manufacturing apparatus includes a light amount control unit 1, an exposure unit 2, and a stage 6. The exposure unit 2 includes a light source 3, a mirror 4, and a lens 5. A photosensitive resin (also referred to as a resist) 12 applied to the substrate 11 is disposed on the stage 6.
The light amount control unit 1 controls the light amount of the laser light applied to the photosensitive resin 12 using a resist sensitivity curve (also simply referred to as “sensitivity curve”). The resist sensitivity curve is acquired in advance. The light amount control unit 1 holds the resist sensitivity curve of the photosensitive resin or is input from the outside when starting to form a fine shape. Moreover, the light quantity control part 1 receives the information (micro shape information) of the fine shape (desired fine shape) to shape | mold from the outside.

  In the fine modeling method, first, a substrate 11 coated with a photosensitive resin 12 is placed on a stage 6. Further, the fine shape information is input to the light quantity control unit 1. Next, the light amount control unit 1 sets the light amount of the laser light irradiated to the photosensitive resin based on the fine shape information and the resist sensitivity curve. Thereafter, the light amount control unit 1 controls the light source 3 to scan the photosensitive resin while modulating the light amount of the laser light in accordance with the set light amount.

Here, the resist sensitivity curve according to the present embodiment is obtained using a method suitable for laser drawing, and is performed by the following procedures (1) to (3).
(1) A test area is set on the photosensitive resin. The test region forms a region in which a plurality of sensitivity measurement regions for measuring sensitivity are adjacent to each other. The plurality of sensitivity measurement regions are adjacent to each other so that different sensitivity measurement regions are arranged in a direction in which laser light is scanned (hereinafter, referred to as “scanning direction” as appropriate).

A rectangular shape (strip shape) is used as the shape of the sensitivity measurement region. The width of one sensitivity measurement region is preferably determined according to the size of the laser spot, preferably 0.5 to 1.4 times the diameter of the laser spot, and preferably larger than the diameter of the laser spot. . In particular, it is preferably 1.2 times the laser spot diameter. For example, when the laser spot has a diameter (φ) of 1 μm, it is preferably 1.2 μm. Here, the width of the sensitivity measurement region indicates the length in the scanning direction.
Further, the plurality of sensitivity measurement regions are arranged adjacent to each other. This is to take into account the influence of the laser light referred to in the adjacent irradiation region. For example, when exposing a region segmented into strips having a width of 1.2 μm, interference light or leakage light may affect adjacent regions. This causes a phenomenon that the resist removal amount increases beyond the set exposure amount. In order to create a resist sensitivity curve in consideration of this, the sensitivity measurement regions are adjacent to each other.

  (2) Scanning is performed while modulating the amount of laser light so that the amount of light differs for each of the plurality of sensitivity measurement regions. The amount of light is preferably adjusted so as to increase or decrease stepwise, that is, to change proportionally in the test area. This takes into consideration that the actual fine shape changes stepwise, and that the influence of exposure on the adjacent region cannot be ignored in order to form the fine shape.

(3) The resist residual film value is measured for each of the plurality of sensitivity measurement regions for the test region obtained by scanning the laser beam. Using the resist residual film value, the relationship between the exposure amount and the resist removal value after development is obtained, and a resist sensitivity curve is created.
The resist sensitivity curve is preferably obtained for each resist type and resist film thickness. Thereby, since the influence of exposure to the strip-shaped region adjacent to the target shape can be included, an error from the target shape can be reduced.
The resist type is an important factor in reducing the error because the sensitivity in the depth direction varies depending on the absolute value of the resist film thickness applied to the substrate.
The resist film thickness is an important factor in reducing the error because the resist film has different resist sensitivity curves when the film thickness is sufficiently larger than the target shape height and when it is the same as the target height.

  Further, it is preferable that there are three types of resist sensitivity curves for each resist type: high sensitivity, medium sensitivity, and low sensitivity. Thereby, the inclination angle of the slope of the target shape can correspond to a range of 3 ° to 80 °. In the resist sensitivity curve, the resist removal amount increases sharply with a certain exposure amount as a threshold value. From this threshold, if there are a plurality of resists having different inclination angles, that is, a plurality of resists having different resist removal amounts according to the amount of laser light, the types of shapes that can be formed can be increased.

If the resist film thickness is determined in a plurality of levels in the range from 5 μm to 50 μm, a fine shape with a height of 0.7 μm to 40 μm can be formed. A fine shape with a height of 1 μm to 30 μm can be stably formed.
It is preferable to create a plurality of resist sensitivity curves according to combinations of a plurality of resist types and a plurality of resist film thicknesses.
In the light amount control unit 1 of the manufacturing apparatus, it is preferable to select an appropriate one from a plurality of resist sensitivity curves according to the resist type and the resist film thickness of the photosensitive resin that forms a fine shape.

  As described above, the resist type and resist suitable for the laser direct drawing method in which the laser spot is about φ1 μm by subdividing the target three-dimensional shape into strips with a width of 1.2 μm and measuring the respective heights. A resist sensitivity curve for each film thickness can be obtained. When a three-dimensional shape is to be formed by this drawing method, the optimum exposure amount for the target shape can be easily obtained by using a resist sensitivity curve suitable for this laser drawing method. Further, by using the resist sensitivity curve, the error from the target shape can be reduced as compared with the case of using the conventional resist sensitivity curve.

  Note that the resist sensitivity curve of the present embodiment can be applied to both a positive type and a negative type photosensitive resin.

[Example]
A. Creation of Resist Sensitivity Curve A resist sensitivity curve was obtained by using the same method as the exposure method for forming a desired fine shape using a laser drawing apparatus having a laser spot of φ1 μm. Here, a positive photosensitive resin was used.
As the test area, eleven sensitivity measurement areas in which strip-shaped patterns with a width of 1.2 μm were arranged without gaps were set in the photosensitive resin. FIG. 2 shows the setting state of the test area. Here, the length of the strip pattern (length in the stage moving direction) was 500 μm.
The amount of laser light applied to the 11 sensitivity measurement regions was changed in proportion from zero to the amount of laser light in which the resist residual film value becomes zero after development. FIG. 3 shows changes in the amount of laser light.
As shown in FIG. 3, the resist residual curve value of the photosensitive resin obtained by changing the amount of light in proportion and exposing and developing was measured to obtain a resist sensitivity curve. The obtained resist sensitivity curve is shown in FIG.

B. Fine Shape Modeling A fine shape was modeled using the resist sensitivity curve shown in FIG. Specifically, the design shape was subdivided into strip-shaped regions having a width of 1.2 μm in advance. The amount of light (exposure power) of the laser beam was obtained using a resist sensitivity curve so that the resist residual film value obtained by exposing each region has a designed shape. The fine shape was modeled by exposing and developing using the obtained amount of laser light.
A difference between the obtained fine shape and the design shape is shown in FIG. In FIG. 5, the horizontal axis indicates the distance from an arbitrary starting point to the scanning direction, and the vertical axis indicates the height at the point on the horizontal axis.
As shown in FIG. 5, the modeled fine shape and the design shape are approximated, and the error between the modeled fine shape and the design shape can be reduced.

[Comparative example]
A. Creation of Resist Sensitivity Curve As a comparative example, the test area was a strip pattern with a width of 1.2 μm, and 11 sensitivity measurement areas with a space of 1.2 μm were set in the photosensitive resin. FIG. 6 shows the setting state of the test area. The length of the strip pattern was 500 μm.
In addition, the resist sensitivity curve was calculated | required like the Example. The obtained resist sensitivity curve is shown in FIG.

B. Fine Shape Modeling Using the resist sensitivity curve shown in FIG. 7, a fine shape was modeled by the same method as in the example.
The error between the modeled fine shape and the design shape was larger than in the example.

  As described above, when the fine shape is formed using the resist sensitivity curve according to the present invention, an error between the fine shape to be formed and the target shape can be reduced as compared with the case where the conventional resist sensitivity curve is used.

  In addition, this invention is not limited to embodiment shown above. Within the scope of the present invention, it is possible to change, add, or convert each element of the above-described embodiment to a content that can be easily considered by those skilled in the art.

DESCRIPTION OF SYMBOLS 1 Light quantity control part 2 Exposure part 3 Light source 4 Mirror 5 Lens 6 Stage 11 Board | substrate 12 Photosensitive resin

Claims (8)

A method for creating a resist sensitivity curve used in manufacturing a fine shape by irradiating a photosensitive resin with laser light to obtain a fine shape,
Set a test area in which a plurality of sensitivity measurement areas are adjacent to the photosensitive resin,
The exposure is performed by modulating the light amount of the laser light so that the light amount is different for each of the plurality of sensitivity measurement regions,
A method for creating a resist sensitivity curve, which obtains a resist sensitivity curve using a test region obtained by developing the photosensitive resin.   2. The method of creating a resist sensitivity curve according to claim 1, wherein the sensitivity measurement region is rectangular and the width of the rectangle is 0.5 to 1.4 times the diameter of the laser spot.   3. The method of creating a resist sensitivity curve according to claim 1, wherein the sensitivity measurement region is rectangular and the width of the rectangle is larger than the diameter of the laser spot.   4. The method of creating a resist sensitivity curve according to claim 1, wherein the light amount of the laser light is modulated stepwise for each of the plurality of sensitivity measurement regions. 5.   The method for creating a resist sensitivity curve according to any one of claims 1 to 4, wherein the resist sensitivity curve is acquired according to a type of the photosensitive resin.   The method for creating a resist sensitivity curve according to claim 1, wherein the resist sensitivity curve is acquired according to a film thickness of the photosensitive resin.   The method for producing a fine shape according to claim 1, wherein the photosensitive resin is a positive type. A method of manufacturing a fine shape by irradiating a photosensitive resin with laser light to obtain a fine shape,
An application step of applying a photosensitive resin to the substrate;
A light amount setting step for setting the light amount of the laser light applied to the photosensitive resin;
An exposure step of scanning the photosensitive resin while modulating the amount of laser light according to the set amount of light;
A developing step for developing the exposed substrate,
The light amount setting step uses the resist sensitivity curve acquired in advance and the fine shape to set the light amount,
The resist sensitivity curve sets a test region in which a plurality of sensitivity measurement regions are adjacent to the photosensitive resin, and modulates the light amount of the laser light so as to have a different light amount for each of the plurality of sensitivity measurement regions. A manufacturing method for fine shapes obtained by scanning.

Images