JPS60224227A - Pattern forming method for resist film - Google Patents

Abstract

PURPOSE:To facilitate the positioning of a photomask accurately and to improve the yield by partly selectively removing a resist film on mask positioning marks of a substrate to expose the mark, and then patterning them. CONSTITUTION:The first photomask 26 for exposing only a thick resist film 25 portion on a mask positioning reference mark 22 of a substrate 21 is disposed on a thick resist film 25, exposed, developed, the film 25 on the mark 22 of the substrate 21 is partly removed selectively to expose the mark 22. Then, the second photomask 27 having the prescribed pattern is disposed on the film 25. At this time since the thick film 25 is not interposed between the mark 22 on the substrate 21 and a positioning mark 28 of the photomask 27, the mark 22 on the substrate 21 can be freshly observed visually, thereby extremely readily bringing the both marks in coincidence.

Description

[Detailed Description of the Invention] ia) Technical Field of the Invention The present invention relates to a method for forming a pattern on a resist film, and in particular, a method for forming a pattern on a resist film, in particular a thick resist film that allows easy and accurate alignment of a photomask and has good pattern accuracy. The present invention relates to a method of forming a film pattern.

...) Background of the technology When manufacturing thin-film magnetic heads and semiconductor integrated circuits, etc.
Thin film formation technology and photolithography technology have become essential technologies.

When patterning a resist film using these techniques, the thickness of the resist film and the accuracy of its pattern width are in a contradictory relationship with each other. In other words, pattern accuracy is good with thin resist films of about 0.2 to 0.5 μm, which are used in the manufacture of semiconductor integrated circuits, but as the film thickness increases, light diffraction phenomenon occurs during exposure. Therefore, the pattern accuracy decreases. In recent years, electronic devices such as thin-film magnetic heads that use thin-film formation technology often have a high step of several μm or more in the lower layer, and if the resist film formed on top of this is thin, step coverage may be poor. Easy to become. Furthermore, when a thin film device is formed using a technique such as plasma etching, ion etching, or mask coating using a resist film pattern as a mask, a thick resist film is inevitably required. However, when the thickness of the resist film becomes as thick as 2 to 5 μm, it becomes extremely difficult to ensure sufficient pattern accuracy.

TCI Prior Art and Problems Conventionally, for example, in the manufacturing process of thin-film magnetic heads, the first
As shown in the figure, a thick resist film 5 coated on a substrate 1 on which a magnetic thin film 3° of various shapes and a non-magnetic insulating layer 4 are laminated and has unevenness, that is, a step, of several μm or more is coated with butter in a predetermined pattern. To do this, a photomask 6 having a predetermined pattern is placed on the thick resist film 5 so that the alignment mark 7 of the photomask 6 matches the reference alignment mark 2 on the substrate 1. The thick resist film 5 is exposed to light through the photomask 6, and then developed to form a thick resist film pattern 8 with a desired fine width as shown in FIG.

By the way, in the conventional thick resist film pattern forming method described above, the thick resist Il! ! A photomask 6 having a predetermined pattern on the substrate 1 is aligned with the alignment mark 7 of the photomask 6 on the reference alignment mark 2 on the substrate 1.
In order to align the alignment mark 7 of the photomask 6, as shown in the schematic sectional view of the main part in FIG. 1 and the partially enlarged plan view of FIG.
The lines are Bl and B of the reference alignment mark 2 on the board 1.
Positioning is performed using a fine adjustment mechanism or the like while visually observing through a resist film 5 that is thicker than in the direction of the arrow, for example through a microscope (not shown), so that the resist film 5 falls between the lines 2 and 2.

However, the thick resist Ill on the reference alignment mark 2 on the substrate 1! Since the film thickness of the photomask 5 is as thick as approximately 3 to 5 μm, the lines of B1 and B2 of the reference alignment mark 2 on the substrate 1 become unclear, making it difficult to align the photomask 6 and resulting in poor alignment accuracy. There was a drawback that it decreased.

(d) Purpose of the Invention In view of the above-mentioned conventional drawbacks, the present invention provides a method for aligning the alignment mark of a photomask so that it coincides with the reference alignment mark on the substrate. , an object of the present invention is to provide a resist film pattern forming method in which a thick resist film thereon is partially exposed to facilitate and accurately align a photomask, thereby improving pattern accuracy. It is something.

(e) Structure and object of the invention According to the present invention, at least one thin film layer is provided on a substrate having mask positioning marks provided at the periphery or on a surface of a region avoiding the mask positioning marks provided at the periphery. A resist film is applied to the entire surface of the substrate, and a photomask having a predetermined pattern is placed on the resist film. Prior to exposure, the resist film on each mask positioning mark on the substrate is partially coated. After selectively removing each mask positioning mark to expose each mask positioning mark, a photomask having a predetermined pattern is positioned and arranged on the resist film with reference to each mask positioning mark on the substrate, and exposed and developed to remove the resist. This is achieved by providing a method for patterning a resist film, which is characterized by patterning the film into a predetermined pattern.

(f) Embodiments of the invention Embodiments of the invention will be described in detail below with reference to the drawings.

FIGS. 4 to 8 are schematic cross-sectional views of essential parts showing one embodiment of the resist film pattern forming method according to the present invention in the order of steps.

First, as shown in FIG. 4, 21 is a substrate with mask alignment reference marks 22 attached to its periphery; 23 is a magnetic film;
4 is a non-magnetic insulating layer, and a resist film 25 made of positive photoresist is applied to a thickness of about 3 μm on the substrate 21 on which steps are formed by the magnetic film 23 and the non-magnetic insulating layer 24. Next, as shown in FIG. 5, a thick resist Ill! is applied on the mask alignment reference mark 22 of the substrate 21 on the thick resist film 5. A first photomask 26 that exposes only the 25 portion is placed, and the exposure/
After development, the thick resist film 25 on each mask positioning reference mark 22 on the substrate 21 is partially selectively removed as shown in FIG.
expose. The purpose of positioning the first photomask 26 in this step is simply to expose each mask positioning reference mark 22 on the substrate 21, so that positioning accuracy is not required.

Next, as shown in FIG. 7, on the thick resist film 25,
A second photomask 27 having a predetermined pattern is arranged so that the alignment mark 28 of the photomask 27 coincides with the mask positioning reference mark 22 on the substrate 21 side. At this time, since the thick resist film 25 is not interposed between the mask positioning reference mark 22 on the substrate 21 and the alignment mark 28 of the photomask 27, the mask positioning reference mark 22 on the substrate 21 is clearly visible. This makes it extremely easy to match both marks.

Thereafter, exposure and development are carried out to form a predetermined pattern, thereby making it possible to easily and accurately form a thick resist film pattern 29 with a desired fine width as shown in FIG.

(Effects of the Invention) As is clear from the above explanation, according to the resist film pattern forming method according to the present invention, the positioning of a photomask for patterning a thick resist film into a predetermined pattern can be performed with high precision and easily. It has excellent effects such as being able to form thick resist film patterns with high accuracy and high yield.Therefore, thin film devices can be fabricated using techniques such as plasma etching, ion etching, or mask plating. This method is extremely advantageous when applied to the formation of thick resist film patterns used in forming.

[Brief explanation of drawings]

Figures 1 and 2 are schematic cross-sectional views of main parts to explain the conventional method of patterning a resist film, and Figure 3 shows a photomask alignment mark aligned with the mask positioning reference mark on the substrate side. Diagram showing one embodiment, 4th F! !
8 are schematic cross-sectional views of main parts showing the method for forming a resist film pattern according to the present invention in the order of steps. In the drawing, 21 is a substrate, 22 is a mask alignment reference mark on the substrate 21, 23 is a magnetic film, 24 is a non-magnetic insulating layer, 25 is a resist film, 26 is a first photomask,
27 is a second photomask, 28 is an alignment mark of the second photomask 27, and 29 is a resist film pattern. Figure 1 Figure 2

Claims (1)

[Claims] A resist film is applied to the entire surface of a substrate having a mask positioning mark attached to the peripheral part, or a substrate having at least one thin film provided on a surface of an area avoiding the mask positioning mark provided in the peripheral part, and Prior to placing a photomask having a predetermined pattern on the film and performing exposure, the resist film on each mask positioning mark on the substrate is partially selectively removed to expose each mask positioning mark. , a resist film characterized in that a photomask having a predetermined pattern is positioned and arranged on the resist film with reference to each mask positioning mark on the substrate, and exposed and developed to pattern the resist film into a predetermined pattern. Pattern formation method.