JPH07102732B2 - Method for forming fine resist pattern - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method capable of forming a resist pattern used in a photolinography technique for manufacturing a semiconductor device or the like with high accuracy and in a large scale.

2. Description of the Related Art An active matrix type liquid crystal display (LCD) in which each pixel is switched by a thin film transistor (TFT) has an advantage that high image quality can be obtained. This active matrix type LCD is in the stage of practical application for pocket TVs and portable TVs, and in recent years, research has been actively conducted to increase the size of this liquid crystal display to 20 inches, 40 inches, and 70 inches diagonally. Has been done to. By the way, in the case of enlarging this liquid crystal display, a photolinography process which is performed when manufacturing a TFT portion of the liquid crystal display, that is, a resist pattern is formed by applying a resist, exposing and developing, and then performing an etching process. There is a problem that enormous cost is required to develop a manufacturing apparatus used in a photolithography process, especially a large-sized exposure apparatus. In order to deal with such a problem, it has been proposed to use a screen printing method or an offset printing method, which has been widely adopted when forming a resist pattern for etching a metal plate or a circuit pattern.

The screen printing method is a method of performing printing by forming an ink shielding mask of a predetermined pattern on a mesh screen, allowing the ink to pass through the penetrating and transmitting portion and adhering it to the printing medium. is there. In this printing method, thick printing of ink (thickness of several μm to 20 μm) is easy, so that there is an advantage that a resist pattern having excellent corrosion resistance can be printed. However, it is difficult to print a fine pattern of 200 μm or less by this screen printing method. In addition, the offset printing method forms a lipophilic part and a hydrophilic part on a PS plate, holds water in the hydrophilic part to repel the oil-based ink, and selectively adheres the ink only to the lipophilic part. This is a method of printing an ink pattern on a printing medium. In this offset printing method, in order to improve printability, the ink pattern on the plate is once transferred to a rubber blanket and then retransferred to a printing medium. This offset printing method has an advantage that relatively fine lines can be obtained. However, with this offset printing method,
Due to the inking method, the transfer operation performed twice, and the like, the printed image line may be as thin as about 1 μm, and the printed image line may have pinholes or disconnections. In addition, if you increase the thickness of the ink applied to the plate to deal with this problem,
As a result, the printed image line becomes thick and the line width of about 100 to 200 μm becomes the limit. The present invention has been made in view of the above problems, and provides a resist pattern forming method capable of forming a resist pattern having a fine and appropriate thickness accurately and clearly, and efficiently and inexpensively. To aim.

According to the present invention, after the image recesses of the intaglio plate for printing are filled with viscous ink, the ink other than the image recesses is removed by a doctor, and then the ink in the image recesses is cured. Then, again, the viscous ink is filled in the image-formed concave portion where the ink is hardened, the ink other than the image-shaped concave portion is removed by a doctor, and then the ink is transferred to a printing medium,
The above problem was solved by forming a resist pattern. As the intaglio plate material used in this forming method, a metal plate such as copper, copper alloy, and stainless is usually used, but various plate materials such as glass and ceramics can be used. The printing plate is usually used in the form of a copper plate roller wound around a rubber roller, but it can also be used in the form of a flat plate. The means for forming the image recesses of a predetermined pattern on the printing plate is not particularly limited, and a mechanical means for forming the image recesses by a fine cutting method on a polished plate material, or photofabrication Various means such as chemical means such as etching to form the image-forming concave portion can be adopted by utilizing the technique. The line width of the image-forming concave portion thus formed is usually 3 to 70 μm.
The degree and the depth (plate depth) are about 1 to 10 μm. In addition, the ink in the image recesses of the intaglio plate for printing is cured by applying heat, ultraviolet rays (UV), infrared rays (IR) or electron beams (EB).
Etc. can be performed by radiation. In the forming method of the present invention, various inks such as an ultraviolet-curable ink such as an acrylic-epoxy ultraviolet curable ink, an infrared (heat) curable ink and an electron beam curable ink can be used. Among them, anaerobic type inks whose curing is inhibited by air, for example, Nisset PE which is an acrylic polymerization type ink
-118 (manufactured by Nippon Carbide Industry Co., Ltd.) and the like are preferable. When this anaerobic type ink is used, when the ink filled in the concave portion of the intaglio image line is hardened, the part on the opening side of the concave part that comes into contact with air is hard to cure and becomes incompletely hardened, leaving adhesiveness There is an advantage that the ink hardened in the recess and the ink refilled later are easily integrated. However, the ink that can be used in the resist pattern forming method of the present invention is not limited to such an anaerobic type ink. When the ink in the image line concave portion is cured as described above, the ink contracts in volume. Then, a recess is formed on the opening side of the image recess. Therefore, in the forming method of the present invention, after that, the image area recesses are filled with the viscous ink again, and then the ink other than the image area recesses is removed by a doctor. The ink used at this time is NS- which is an oxidative polymerization type.
Ink having an adhesive property such as 50 (manufactured by Moroboshi Ink Co., Ltd.) may be used, or may be the same as the ink used for the first time. If it is not easy to transfer the ink in the image recesses to the printing medium, a thin adhesive or adhesive coating may be formed on the substrate in advance. As a material for forming such a coating, there are various commercially available products.
There are solvent activation type, heat activation type, pressure activation type, chemical reaction type and the like in the adhesion process. In this case, it is necessary to remove the unnecessary portion of the applied tacky or adhesive coating, but the unnecessary portion of the coating is removed by dry etching such as plasma,
It can be performed by an etching method such as wet etching with an etching solution. Further, when a resist pattern is formed on the substrate for forming a thin film transistor having an uneven surface, for example, a substrate that has been subjected to a process, by the forming method of the present invention, it is preferable to apply a photoresist on the substrate in advance and then transfer the ink. The photoresist applied to the substrate is subjected to an exposure treatment with ultraviolet rays or the like by using the transferred ink as a masking resist, and then an unnecessary portion is removed by etching. As the ink used in this case,
If the photoresist is an ultraviolet curable type, an ink in which carbon black capable of blocking ultraviolet rays, an ultraviolet absorbing pigment and the like are mixed is suitable.

In the method of forming a resist pattern according to the present invention, an intaglio plate is used as a plate, the ink filled in the image recess of the intaglio is cured, and then the ink is filled in the image recess again. Since it is transferred to a printing substrate such as a forming substrate, the first ink, which has become non-fluid due to disappearance of fluidity due to thickening or curing in the image concave portion by the curing treatment, is patterned on the plate. The shape is kept as it is and transferred to the printing medium by the adhesive force of the second ink. Therefore, according to this forming method, an ink layer (resist pattern) having a fine pattern can be formed as a plate. Further, according to the forming method of the present invention, the ink transferred to the substrate for forming a thin film transistor, which is the printing medium, is contained in the image recesses of the intaglio plate, so that the ink is not crushed during the transfer. . Therefore, according to the forming method of the present invention, it is possible to form a resist pattern having an appropriate thickness according to the depth of the image recessed portion of the plate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a method for forming a resist pattern according to the present invention will be described with reference to the drawings. (Embodiment 1) FIGS. 1 to 5 show an embodiment of a method of forming a resist pattern according to the present invention in the order of steps, in which reference numeral 1 is a printing plate. This printing plate 1 is an intaglio plate made of a copper plate and is wound around a rubber roller 20. The printing plate 1 is patterned with an image recess 2 corresponding to a resist pattern for forming a semiconductor film of a TFT. The image line concave portion 2 is formed by an etching process and has a minimum line width of 20 μm and a depth (plate depth) of 3 μm.
It was m. As shown in FIG. 2, an acrylic-epoxy UV-curable ink 3 is applied to the surface of the printing plate 1, and then unnecessary ink is scraped off with a doctor 4 composed of a thin metal blade or the like. Only the recess 2 was filled with the ink 3. After that, when the ink 3 was cured by irradiating the surface of the printing plate 1 with ultraviolet rays for a predetermined time, the ink 3 was cured and shrunk as shown in FIG. 5 occurred. Next, as shown in FIG. 4, the ink 6 was applied to the surface of the printing plate 1 again, and unnecessary ink was scraped off by the doctor 4 so that only the image line recess 2 was filled with the ink 6. The ink 6 used at this time was the same as the ink 3 used for the first time. Next, as shown in FIG. 5, the printing plate 1 is placed on the TFT substrate (printing material) 7 on which the p-Si film 6 is formed, the positions are accurately aligned, and the two are brought into close contact with each other and slowly rolled. , Ink 6 (uncured) and ink 3 (cured) were transferred. When the printing plate 1 is separated from the substrate 7, the (unhardened) ink 6 and the (hardened) ink 3 in the image recess 2 become the TFT substrate 7.
Then, the resist pattern having a minimum line width of 20 μm and a film thickness of 3 μm was accurately reproduced. In this resist pattern forming method, an intaglio plate is used as the plate 1, the ink 3 filled in the image line concave portion 2 of the intaglio plate 1 is cured, and then the image line concave portion 2 is filled with the ink 6 again.
Since the ink 3 has been transferred to the substrate 7, the ink 3 thickens or cures in the image recess 2 and maintains the shape of the image recess 2 as it is (uncured).
Is transcribed to. Moreover, even if the volume of the first ink 3 shrinks during the curing process, that portion is compensated by the second ink 6, so that the inks 3 and 6 firmly adhere to the substrate 7 and are transferred smoothly. Therefore, according to this forming method, it is possible to form a fine resist pattern composed of the inks 3 and 6 according to the plate. Further, according to this resist pattern forming method, since the ink 3 transferred to the TFT substrate 7 is contained in the image-forming concave portion 2 of the intaglio plate 1, the ink 3 is not crushed during the transfer. Therefore, according to this forming method, it is possible to form a resist pattern having an appropriate thickness according to the depth of the image-forming concave portion 2 of the plate 1.

As described above, according to the method of forming a fine resist pattern of the present invention, after the viscous ink is filled in the image concave portions of the intaglio plate for printing, the ink in the non-image area other than the image concave portions is doctored. Then, the ink in the image recess is cured, and then the viscous ink is filled again in the image recess in which the ink is cured, and the ink other than the image recess is removed with a doctor. Since the method is characterized in that the ink is transferred to the printing material to form a resist pattern, by hardening the first ink, the ink thickens or hardens in the image recesses, and the fluidity of the ink disappears. . Then, the first-time ink becomes in a non-fluid state and the pattern shape on the plate is kept as it is, and is transferred to the printing medium by the adhesive force of the second-time ink. At this time, even if the volume of the first ink shrinks during the curing process, that portion is compensated by the second ink, so that the ink firmly adheres to the substrate and is transferred smoothly. Therefore, according to the forming method of the present invention, a fine resist pattern made of ink can be formed according to the plate. Further, according to the forming method of the present invention, since the ink transferred to the TFT substrate is contained in the image line concave portion of the concave plate, the ink is not crushed during the transfer. Therefore, according to the forming method of the present invention, it is possible to form a resist pattern having a thickness corresponding to the depth of the image recesses of the plate. Therefore, according to the method for forming a resist pattern of the present invention, a resist pattern having a fine and appropriate thickness can be formed accurately and clearly, efficiently and inexpensively.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a plate used in a method for forming a resist pattern according to an embodiment.

FIG. 2 is a cross-sectional view showing a step of filling ink for the first time by the forming method of the embodiment.

FIG. 3 is a cross-sectional view showing a step of curing the ink filled in the first time by the forming method of the embodiment.

FIG. 4 is a cross-sectional view showing a step of filling ink for a second time by the forming method of the embodiment.

FIG. 5 is a cross-sectional view showing a step of transferring ink to a printing medium by the forming method of the embodiment.

[Explanation of symbols]

 1 Intaglio 2 Image line recess 3 Ink 4 Doctor 5 Indentation 6 Ink 7 TFT substrate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazunori Nakamura 1-6-5 Higashi Nihonbashi, Chuo-ku, Tokyo Inside GTC (56) References JP-A-60-39888 (JP, A) JP-A 3-19889 (JP, A)

Claims (1)

[Claims] 1. A printing intaglio image drawing concave portion is filled with viscous ink, and then ink other than the drawing concave portion is removed by a doctor,
Then, the ink in the image recesses is cured, and then the viscous ink is filled again in the image recesses in which the ink has been cured, and then the ink other than the image recesses is removed with a doctor, after which the ink is applied to the printing medium A method for forming a fine resist pattern, which comprises transferring to form a resist pattern.