JP2010115829A - Pattern forming method and method for manufacturing liquid discharge head - Google Patents

Abstract

There is provided a pattern forming method capable of producing a mold material having a good patterning shape by suppressing a decrease in taper angle of the pattern shape.
In a pattern forming method of forming two photoresist layers on a substrate and forming patterns having different shapes for each layer, (a) a first photoresist film and a second photoresist film are sequentially formed on the substrate. (B) forming a pattern to be formed on the first photoresist film on the first and second photoresist films and developing the pattern; and (c) forming the pattern on the second photoresist film. A pattern is exposed to the second photoresist film and developed, and the absorption wavelength region of the first photoresist film partially overlaps with the absorption wavelength region of the second photoresist film. The pattern forming method, wherein the exposure wavelength in the step (b) includes a wavelength component in the overlapping absorption wavelength region.
[Selection] Figure 5

Description

  The present invention relates to a photoresist pattern forming method. In addition, the present invention relates to a method for manufacturing a liquid discharge head to which it is applied, and more specifically to a method for manufacturing an ink jet recording head that performs recording by discharging ink onto a recording medium.

  An ink jet recording head applied to an ink jet recording method (liquid jet recording method) generally includes a fine ink discharge port, an ink flow path, and an energy generating element used for discharging ink provided in a part of the ink flow path. There are multiple. In order to obtain a high-quality image with such an ink jet recording head, ink droplets discharged from the ink discharge ports are always discharged from the respective ink discharge ports at the same volume and the same discharge speed. It is desirable. In particular, the smaller the droplets that are ejected and the higher the density, the greater the impact on image quality. Needless to say, patterns are formed when they are formed in a limited device space. Shape and accuracy are important.

  The form of an ink jet recording head used in such a recording method or recording apparatus is disclosed in Patent Document 1. In a method of manufacturing a liquid discharge head including such an ink jet recording head, the following steps are known as a method for forming a flow path pattern. In this method, a pattern forming a flow path is formed with a photoresist film on a surface where an energy generating element is arranged on a substrate, pattern exposure is performed, and then development processing is performed.

  FIG. 4 is a schematic sectional view showing an example of a conventional pattern forming method. FIG. 4A shows a step of applying and forming a first photoresist film 9 as a lower mold material, and FIG. 4B shows a step of applying and forming a second photoresist film 10 as an upper layer. FIG. 4C shows a step of exposing and developing the upper second photoresist film 10 using the second photoresist pattern mask 11. FIG. 4D shows a process of exposing and developing the lower first photoresist film 9 using the first photoresist pattern mask 12, and the pattern is completed in FIG. 4E. In this pattern formation method, patterns having different shapes can be formed for the first photoresist film 9 and the second photoresist film 10 respectively.

Further, in the conventional method, when forming a mold material photoresist film as a flow path pattern on the substrate in two layers, an upper layer and a lower layer, in order to prevent the first photoresist film and the second photoresist film from being mixed, The first photoresist film is baked before forming the film.
JP 2006-44237 A

  In the conventional pattern forming method, depending on the baking conditions and the like, the amount of solvent contained in the first photoresist film may be reduced and the sensitivity may be lowered, so that the taper angle of the pattern shape may become dull. In the future, in order to improve image quality, a pattern shape with higher shape accuracy is required for increasing the density of nozzles.

  Furthermore, in pattern exposure of the first photoresist film and the second photoresist film, when exposure is performed by proximity exposure, the taper angle of the pattern shape tends to be dull due to the influence of diffracted light generated during pattern exposure. Diffracted light is light that spreads from the mask edge portion to the photoresist film during pattern exposure, and affects the pattern shape. Diffracted light also has a relationship with material sensitivity.As described above, the amount of exposure during pattern exposure increases as the solvent content of the photoresist film decreases and the material sensitivity decreases. The taper angle of the pattern shape becomes blunt. In addition, since pattern exposure and development are performed separately, pattern misalignment between the first photoresist film and the second photoresist film may occur due to apparatus alignment accuracy.

  An object of the present invention has been made in view of the above-described problems, and an object of the present invention is to provide a pattern forming method capable of producing a mold material having a good patterning shape by suppressing a decrease in taper angle of the pattern shape. Another object of the present invention is to provide a method for manufacturing a highly reliable liquid discharge head in which the adhesion between the nozzle wall and the base plate is ensured even when the nozzle density is improved by using the pattern forming method.

  The pattern forming method according to the present invention is a pattern forming method in which two photoresist layers are formed on a substrate, and a pattern having a different shape is formed on each layer. A step of sequentially forming a photoresist film; (b) a step of exposing the first and second photoresist films to a pattern to be formed on the first photoresist film and developing the pattern; and (c) the second photo film. And exposing and developing a pattern formed on the resist film on the second photoresist film, and having an absorption wavelength region of the first photoresist film and an absorption wavelength region of the second photoresist film. And the exposure wavelength in the step (b) includes a wavelength component in the overlapping absorption wavelength region.

  The absorption wavelength region of the first photoresist film is in the range of 365 nm or less, and the absorption wavelength region of the second photoresist film is in the range of 260 nm or less.

  The first photoresist film may be thicker than the second photoresist film.

  The first photoresist film may have a thickness of 10 to 14 μm, and the second photoresist film may have a thickness of 3 to 5 μm.

  The first photoresist film and the second photoresist film are positive photoresists.

  The exposure in the steps (b) and (c) is proximity exposure.

  The method for manufacturing a liquid discharge head according to the present invention includes a substrate having an energy generating element that generates energy used for discharging a liquid, a discharge port that discharges the liquid, and a flow of the liquid that communicates with the discharge port. In the method of manufacturing a liquid discharge head having a path, a step of forming a pattern of the flow path on the substrate by the pattern forming method, and a step of providing a coating layer covering the pattern on the pattern And the step of removing the pattern and forming the flow path.

  According to the pattern forming method of the present invention, the perpendicularity of the pattern shape of the lower photoresist film can be improved even when patterns having different shapes are formed on the two photoresist films.

In the pattern forming method according to the present invention, a two-layer photoresist film is formed on a substrate, and a pattern having a different shape is formed for each layer.
(A) sequentially forming a first photoresist film and a second photoresist film on a substrate;
(B) a step of exposing the first and second photoresist films together with a pattern to be formed on the first photoresist film and developing the pattern;
(C) exposing and developing a pattern to be formed on the second photoresist film on the second photoresist film; and
And having
The absorption wavelength region of the first photoresist film partially overlaps with the absorption wavelength region of the second photoresist film,
The exposure wavelength in the step (b) includes a wavelength component in the overlapping absorption wavelength region.

  In the present invention, in order to perpendicularize the taper angle of the pattern shape of the lower first photoresist film, the first and second photoresist films are collectively exposed after the upper second photoresist film is formed. Further, although the absorption wavelength region of the lower first photoresist layer and the absorption wavelength region of the upper second photoresist layer are different, there is a partially overlapping range, and the exposure wavelength of the batch exposure is a wavelength component in the overlapping range. including. Thereby, the upper second photoresist film partially absorbs the diffracted light at the time of the proximity exposure, and the taper angle of the pattern shape due to the diffracted light to the lower first photoresist film can be prevented from being blunted.

  According to the present invention, the perpendicularity of the pattern shape is improved. Hereinafter, a pattern forming method according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to these.

  FIG. 5 is a schematic cross-sectional view showing an example of a pattern forming method according to an embodiment of the present invention.

  FIG. 5A shows a process of applying and forming a first photoresist film 9 which is a lower mold material on a substrate. FIG. 5B shows a step of coating and forming a second photoresist film 10 serving as an upper mold material on the first photoresist film 9.

  As the material for the first photoresist film and the second photoresist film, a positive photoresist in which the absorption wavelength regions of the respective materials partially overlap is used. For example, a positive photoresist having an absorption wavelength region of 365 nm or less can be used for the first photoresist film, and a positive photoresist having an absorption wavelength region of 260 nm or less can be used for the second photoresist film. Specifically, an acrylic resin or the like can be used as the first photoresist film. An acrylic resin or the like can also be used as the second photoresist film.

  The film thickness of the first photoresist film 9 is preferably larger than the film thickness of the second photoresist film 10 from the viewpoint of ink ejection. Specifically, the film thickness of the first photoresist film 9 is preferably 10 to 14 μm. The film thickness of the second photoresist film 10 is preferably 3 to 5 μm.

  As a method of applying the first photoresist film 9 and the second photoresist film 10, a conventional method can be used, and for example, it can be applied by a spin coat method. Before applying the second photoresist film 10, it is necessary to perform an additional baking at 150 ° C. or higher in order to prevent the first photoresist film 9 and the second photoresist film 10 from being compatible.

  FIG. 5C shows a step of collectively exposing the first photoresist film 9 and the second photoresist film 10 using the first photoresist pattern mask 12 in the pattern forming method according to the embodiment of the present invention. .

  In the pattern formation according to the present invention, as long as the pattern exposure method is proximity exposure, the taper angle of the pattern shape is likely to be increased due to the influence of diffracted light. Further, as described above, the lower first photoresist film is additionally baked to prevent compatibility with the upper second photoresist film. As a result, the amount of residual solvent in the film itself is reduced, and the sensitivity is also lowered, whereby the pattern shape is tapered.

  As is generally known, in order to improve the perpendicularity of the pattern shape of the first photoresist film, the taper angle may be dull due to the influence of proximity exposure, and it is assumed that it can be eliminated by contact exposure. . However, due to the sensitivity of the first photoresist film itself and the additional bake introduced to prevent compatibility, the taper angle of the pattern shape of the first photoresist film has little effect even if the exposure GAP amount is reduced. It has been confirmed.

  Therefore, in the present invention, the first photoresist film and the second photoresist film are collectively exposed to prevent the taper angle of the pattern shape from becoming blunt.

  FIG. 1 is a schematic view showing the flow of exposure light during pattern exposure in this step and the flow of diffracted light generated at that time.

  FIG. 1A is a diagram showing a case where the first photoresist film and the second photoresist film are collectively exposed. By pattern exposing the upper second photoresist film and the lower first photoresist film at once, the second photoresist film partially absorbs the diffracted light to the first photoresist film, and the first photoresist film The verticality of the pattern shape angle is improved.

  On the other hand, FIG. 1B shows a case where pattern exposure of the second photoresist film as the upper layer, which is a conventional method, is performed, and then pattern exposure of the first photoresist film as the lower layer is performed. . In this case, since the first photoresist film is directly affected by the diffracted light because the second photoresist film does not absorb the diffracted light generated during the pattern exposure of the first photoresist film, the taper angle of the pattern shape is slowed down. To do.

  In the present invention, as shown in FIG. 1 (a), the second photoresist film absorbs part of the diffracted light to the first photoresist film. And a wavelength component of a region where the absorption wavelength region of the first photoresist film and the absorption wavelength region of the second photoresist film overlap. By including the wavelength of the overlapping region, part of the diffracted light having the wavelength of the overlapping region is absorbed by the second photoresist film, and the taper angle of the first photoresist film can be prevented from being blunted. .

  FIG. 5 (d) shows patterns (9b and 10b) after developing the first and second photoresist films which are collectively exposed in FIG. 5 (c).

  Thereafter, as shown in FIG. 5D, the pattern formed on the second photoresist film is exposed to the second photoresist film through the second photoresist mask pattern 11 and developed. Thereby, as shown in FIG.5 (e), a 2nd photoresist film can be made into the predetermined pattern 10a. Thus, patterns having different shapes can be formed for the first photoresist film and the second photoresist film, respectively.

  In exposing the second photoresist film, exposure is performed with an exposure light of 260 nm or less.

  In the above description, for simplification, the case where the pattern widths of the first photoresist film and the second photoresist film are different has been described. However, it is needless to say that the present invention can also be applied to patterns different in the vertical direction of the paper surface of FIG. 5, for example, when the first photoresist is a linear pattern and the second photoresist is a dot pattern.

  As described above, the pattern forming method according to the present invention includes a substrate having an energy generating element that generates energy used to discharge a liquid, a discharge port that discharges the liquid, and a liquid that communicates with the discharge port. In a method for manufacturing a liquid discharge head having a flow path, the method can be used for a method of forming a pattern of the flow path on the substrate.

  As shown in FIGS. 2 and 3, the form of an ink jet recording head used in a recording method or a recording apparatus has a substrate 1 provided with an energy generating element 2 for generating energy for liquid ejection. The substrate 1 has an orifice plate 7 provided with an ink discharge port 6 corresponding to the energy generating element 2, and an ink supply port 5 for supplying ink to the ink flow path 4, and the surface of the substrate 1 and the orifice plate 7. Droplets are ejected in a substantially vertical direction.

  FIG. 7 is a cross-sectional view taken along the B-B ′ cross section in FIG. 2, and is a schematic cross-sectional view illustrating an example of a method of manufacturing a liquid discharge head according to the present invention.

  As shown in FIG. 7 (a), after forming a pattern on the substrate 1 by the method according to the present invention, a coating layer 7 for covering the pattern is provided in FIG. 7 (b), and the liquid is applied in FIG. 7 (c). A discharge port 6 for discharging and an orifice plate 7a are formed. Thereafter, after forming the supply port 5 for supplying the liquid in FIG. 7D, the liquid channel 4 communicating with the discharge port 6 is formed by removing the pattern in FIG. 7E. The liquid discharge head is completed.

  Examples according to the present invention are shown below, but the present invention is not limited to these.

Example 1
In the pattern forming method according to the example of the present invention, first, a first photoresist film was formed on a substrate to be processed.

  As a material for the first photoresist film, a deep UV resist (trade name: “ODUR”, manufactured by Tokyo Ohka Kogyo Co., Ltd.), which is a positive type photoresist having an absorption wavelength range of 365 nm or less, was used. The first photoresist film was formed by spin coating so as to have a thickness of 10 μm to 14 μm.

  Thereafter, in order to prevent compatibility with the second photoresist film, an additional baking at 150 ° C. was performed and cooled.

  Next, similarly to the first photoresist film, a second photoresist film was formed by spin coating so as to have a thickness of 3 μm to 6 μm. As the material for the second photoresist film, a polymethyl methacrylate resist (PMMA, manufactured by Starlight Polymer), which is a positive photoresist, was used in the same manner as the first photoresist film, with an absorption wavelength range of 260 nm or less. .

  Next, the first photoresist film and the second photoresist film were subjected to pattern exposure and development in a lump.

  FIG. 6 shows the absorbance with respect to the exposure wavelength in the first photoresist film and the second photoresist film, the mold material exposure intensity with respect to the exposure wavelength of the batch exposure of the first and second photoresist films and the exposure of the second photoresist film described later, It is the graph which showed. Of the diffracted light in the batch exposure of the first and second photoresist films, the diffracted light having a wavelength of 260 nm or less where the absorption wavelength regions of the first and second photoresist films overlap is absorbed by the second photoresist film. Therefore, it does not reach the first photoresist film. Therefore, a part of the diffracted light is shielded, and the taper angle of the first photoresist film can be prevented from being blunted.

As a pattern exposure apparatus, a proximity type exposure apparatus was used. The exposure GAP was 30 μm, and when the first photoresist film and the second photoresist film were exposed at once, the exposure was performed using a bandpass filter. Exposure of the second photoresist film 10J / m ^2, an exposure amount of the first photoresist film becomes 26J / m ² approximately, and an exposure amount setting residue after development becomes zero.

  Thereafter, the second photoresist film was exposed with an exposure light of 260 nm or less and developed to form patterns having different shapes for the first photoresist film and the second photoresist film, respectively.

(Comparative Example 1)
After forming the first photoresist film and the second photoresist film in the same manner as in Example 1, the pattern was exposed and developed on the second photoresist film, and then the pattern was exposed and developed on the second photoresist film. About the used material, exposure wavelength, etc., it carried out on the conditions similar to Example 1. FIG.

  Comparing the taper angles of the pattern shapes of the first photoresist films formed in Example 1 and Comparative Example 1, as shown in FIG. The verticality was improved by about 7 ° and about 7 °.

(A) It is an exposure state at the time of pattern formation by embodiment of this invention, and a schematic diagram of diffracted light. (B) It is the exposure state at the time of pattern formation by the conventional embodiment, and a schematic diagram of diffracted light. This is a nozzle form of an ink jet recording head used in a recording method or a recording apparatus. FIG. 3 is an A-A ′ sectional view of a nozzle form of an ink jet recording head used in the recording method or recording apparatus of FIG. 2. It is a schematic diagram of the detailed process flow of mold material (ink flow path) formation by the conventional form. It is a schematic cross section which shows an example of the pattern formation method of this invention. FIG. 6 is a graph showing the absorbance of the first photoresist film and the second photoresist film with respect to the exposure wavelength, the mold material exposure intensity with respect to the exposure wavelength of the first and second photoresist films, and the exposure wavelength of the second photoresist film described later. is there. It is a schematic diagram of the detailed process flow of the manufacturing method of a liquid discharge head.

Explanation of symbols

1 Substrate 2 Energy generating element 3 Channel wall (ink channel wall)
4 channel (ink channel)
5 Supply port (ink supply port)
6 Discharge port (ink discharge port)
7 Orifice plate 9 First photoresist film 9a, 9b Pattern 10 formed on first photoresist film Second photoresist film 10a, 10b Pattern 11 formed on second photoresist film 11 Mask pattern 12 for second photoresist film 1 Mask pattern for photoresist film

Claims (7)

In a pattern forming method of forming two photoresist layers on a substrate and forming patterns having different shapes for each layer,
(A) sequentially forming a first photoresist film and a second photoresist film on a substrate;
(B) a step of exposing the first and second photoresist films together with a pattern to be formed on the first photoresist film and developing the pattern;
(C) exposing and developing a pattern to be formed on the second photoresist film on the second photoresist film; and
And having
The absorption wavelength region of the first photoresist film partially overlaps with the absorption wavelength region of the second photoresist film,
The pattern forming method, wherein the exposure wavelength in the step (b) includes a wavelength component in the overlapping absorption wavelength region.   2. The pattern forming method according to claim 1, wherein an absorption wavelength region of the first photoresist film is in a range of 365 nm or less, and an absorption wavelength region of the second photoresist film is in a range of 260 nm or less.   The pattern forming method according to claim 1, wherein the film thickness of the first photoresist film is larger than the film thickness of the second photoresist film.   4. The pattern forming method according to claim 1, wherein the film thickness of the first photoresist film is 10 to 14 μm, and the film thickness of the second photoresist film is 3 to 5 μm. 5. .   The pattern forming method according to claim 1, wherein the first photoresist film and the second photoresist film are positive photoresists.   The pattern forming method according to claim 1, wherein the exposure in the steps (b) and (c) is proximity exposure. A substrate having an energy generating element for generating energy used for discharging liquid;
A discharge port for discharging liquid;
A liquid flow path communicating with the discharge port;
In a method of manufacturing a liquid discharge head having
Forming the pattern of the flow path on the substrate by the method according to any one of claims 1 to 6;
Providing a coating layer covering the pattern on the pattern;
Removing the pattern and forming the flow path;
A method of manufacturing a liquid discharge head, comprising:

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