JPH0523876A - Formation of fine pattern of organic insulating layer - Google Patents

Abstract

PURPOSE:To allow the formation of fine patterns on an org. insulating layer by allowing the formation of the fine patterns on the org. insulating layer with a simple stage and eliminating the need for dangerous chemicals and waste liquid treating facilities. CONSTITUTION:A photoresist film 3 is formed on the insulating layer 2 consisting of org. matter having a high insulating characteristic and is exposed and developed with the desired patterns, by which the unnecessary parts of the insulating layer 2 are exposed. The insulating layer 2 is evaporated by the irradiation with an excimer laser 4 and is patterned; thereafter, the photoresist film 3 is removed.

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 fine pattern of an organic insulating layer which is effective when applied to a circuit board having a highly insulating organic material as an insulating layer.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view of a step for explaining a conventional method for forming a fine pattern of an organic insulating layer. In the figure, as shown in FIG. 2A, an insulating layer 2 made of a highly insulating organic material is formed on a substrate 1. Next, as shown in FIG. 2B, a photoresist film 3 is deposited on the surface of the insulating layer 2 and then the photoresist film 3 is exposed and developed to develop the insulating layer 2.
Expose unnecessary parts of. Next, as shown in FIG. 2C, the substrate 1 is dipped in a hydrazine solution 5 to etch unnecessary portions of the insulating layer 2, and the photoresist film 3 is removed as shown in FIG. 2D.

As described above, in a circuit board having a highly insulating organic material as an insulating layer, a wet etching method using a strong alkaline solution such as hydrazine solution 5 has been used as a method for forming a fine pattern of the insulating layer.

[0004]

In the conventional method for forming a fine pattern of an organic insulating layer, a wet etching method using a strong alkaline solution such as hydrazine solution 5 is used for etching the organic insulating layer. In addition to the control of the etching time and the etching time, a cleaning step and a drying step after etching are required, which complicates the steps and requires the use of a highly corrosive and dangerous chemical. There is also a problem that a processing facility for etching liquid and cleaning liquid is required.

Therefore, the present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to obtain a fine pattern of an organic insulating layer in a simple process without using dangerous chemicals or exhaust treatment facilities. Another object of the present invention is to provide a method for forming a fine pattern of an organic insulating layer.

[0006]

In order to achieve such an object, the method of forming a fine pattern of an organic insulating layer according to the present invention forms an insulating layer made of a highly insulating organic substance on a substrate, After depositing a photoresist film on the surface, the photoresist film is exposed and developed to expose unnecessary portions of the insulating layer, and the exposed insulating layer is irradiated with excimer laser to evaporate the insulating layer. A pattern is formed, and then the photoresist film is removed.

[0007]

In the present invention, the fine pattern of the organic insulating layer is formed by a simple process.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a sectional view of a process for explaining an embodiment of a method for forming a fine pattern of an organic insulating layer according to the present invention.
In the figure, first, as shown in FIG. 1A, an insulating layer 2 made of a highly insulating organic material is formed on a substrate 1 made of alumina ceramic or the like. Next, as shown in FIG. 1B, a polyimide precursor varnish is uniformly applied on the entire surface of the substrate 1 by means of spin coating, spray coating, roll coating, etc., and then 350 ° C. to 400 ° C. When heat-treated at 10 ° C. for 10 to 20 minutes, the insulating layer 2 of polyimide resin, which is a highly insulating organic substance, can be formed on the substrate 1. As the highly insulating organic material, polyamide, fluorinated ethylene propylene, or the like can be used in addition to polyimide. Next in FIG.
As shown in (b), a photoresist solution is uniformly applied to the entire surface of the insulating layer 2 by a spinner method or the like to a thickness of 5 μm to 10 μm, and this is heated at 70 ° C. to 100 ° C. to be hardened to form an insulating layer. After depositing the photoresist film 3 on the surface of 2, the desired pattern is exposed and developed to expose unnecessary portions of the insulating layer 2. Next, as shown in FIG. 1C, the entire surface of the substrate 1 is irradiated with an excimer laser 4, and the unnecessary portion of the insulating layer 2 exposed by using the photoresist film 3 as an etching mask is etched. Here, when the excimer laser 4 is irradiated to the insulating layer 2 made of a highly insulating organic material, the carbon bond is broken by the energy of the ultraviolet rays and is evaporated. The insulating layer 2 in the portion where the photoresist film 3 is applied as an etching mask remains unetched because the excimer laser 4 does not hit it, but the insulating layer in the portion where the photoresist film 3 is not applied remains. Since the excimer laser 4 hits and is etched, a desired pattern can be generated. Next, as shown in FIG. 3D, the photoresist film 3 deposited on the insulating layer 2 is removed. In this case, the highly insulating organic substance evaporated by irradiation with the excimer laser 4 becomes soot and adheres to the periphery of the irradiated portion. For this reason, a step of removing the soot of the highly insulating organic substance is required. According to the method of this embodiment, the soot of the highly insulating organic substance adheres to the surface of the photoresist film 3 which is the etching mask. Therefore, the photoresist film 3 can be removed at the same time as it is removed.

Next, a case where a dry film resist is used will be described as another embodiment of the present invention. The dry film resist is a commercially available acrylic resin-based photo dry film, and it is sufficient to use one in which the exposed portion is polymerized and is not dissolved in the developing solution, and only the unexposed portion is dissolved and peeled in the developing solution. . Then, this dry film resist is thermocompression-bonded and deposited on the insulating layer 2 made of a highly insulating organic material. Then, similarly to the above-mentioned FIG. 1B, exposure and development are performed to expose unnecessary portions of the insulating layer 2. Next, when the excimer laser 4 is irradiated with this dry film resist as an etching mask, the exposed unnecessary portion of the insulating layer is evaporated as shown in FIG. 1C, and a desired pattern can be generated. Then, if the dry film resist deposited on the insulating layer 2 is peeled off, as shown in FIG.
The insulating layer 2 having a pattern similar to that of is obtained. In this dry film resist example, a thick resist film can be obtained by a simple process as compared with the case where a resist solution is used.

[0010]

As described above, according to the present invention,
An insulating layer made of a highly insulating organic material is formed on a substrate, a photoresist film is deposited on the surface of the insulating layer, and then the photoresist film is exposed and developed to expose unnecessary portions of the insulating layer, Irradiation of excimer laser to the insulating layer of this exposed portion, the insulating layer is evaporated to form a pattern, and after that, by removing the photoresist film, a fine pattern of the highly insulating organic insulating layer is formed. It can be obtained by a simple process, and its practical effect is extremely large because it is a dry etching method that does not use this dangerous chemical or waste liquid treatment facility.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a process illustrating an embodiment of a method for forming a fine pattern of an organic insulating layer according to the present invention.

FIG. 2 is a cross-sectional view of a step illustrating a conventional method for forming a fine pattern of an organic insulating layer.

[Explanation of symbols]

1 substrate 2 insulating layers 3 Resist film 4 excimer laser 5 hydrazine solution

Claims (3)

[Claims] 1. An insulating layer made of a highly insulating organic material is formed on a substrate, a photoresist film is deposited on the surface of the insulating layer, and then the photoresist film is exposed and developed to eliminate the need for the insulating layer. Exposing a portion, irradiating the insulating layer of the exposed portion with an excimer laser, evaporating the insulating layer to form a pattern, and thereafter, removing the photoresist film A fine pattern of the organic insulating layer Forming method. 2. The method for forming a fine pattern of an organic insulating layer according to claim 1, wherein the photoresist film is thicker than the insulating layer. 3. The method for forming a fine pattern of an organic insulating layer according to claim 1, wherein the photoresist film is a dry film resist film, and the dry film resist film is deposited by thermocompression bonding.