JPS63220522A - Pattern formation - Google Patents

Abstract

PURPOSE:To expose specified mask patterns, and to form fine patterns accurately without depending upon the size of the patterns by shaping all mask patterns as an aggregate in which unit rectangular patterns having the same shape are brought near. CONSTITUTION:A novolak group positive type photo-resist (a resist) as a radiation sensitive resin is applied onto a substrate, and soft-baked. The resist is exposed by using a projection exposure device through a mask 20 having a line pattern 10 in which four rectangular patterns are separated and arranged rectilinearly as unit rectangular patterns 1, a square pattern 11, in which four said unit mask patterns are separated and disposed to a square shape, and the fine square pattern 12 of the single unit pattern. Lastly, an exposure section is developed and removed by a developer in the resist. Accordingly, the excellent fine patterns can be shaped without depending upon the size of the patterns.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of forming a pattern, particularly a method of forming a fine pattern using radiation.

2. Description of the Related Art In microfabrication techniques used for manufacturing semiconductor integrated circuits, the minimum processed line width is 1 μm or less. When forming fine patterns with processing dimensions of 1 μm or less using ultraviolet rays or electron beams, the amount of irradiation applied to the resist film decreases as the pattern dimensions become smaller. However, a so-called size effect occurs in which the pattern size after resist development is large and widens, while small patterns are narrowed. For this reason, it was necessary to modify the dimensions of the caulking mask pattern during ultraviolet exposure.

For example, a rectangular shape with a 0.5 μm opening and a 2. ○μmo rectangle,
When exposed to ultraviolet light with a wavelength of 438 nm using a projection influence exposure device with an NA of 0.3, a pattern of 0.5 μm lobata was not formed due to insufficient exposure, and on the contrary, a pattern of 2.0 μm loba pattern was If overexposure occurs, the pattern size will increase. Therefore, appropriate exposure was performed by making the mask pattern for forming a 0.5 μm lobe pattern thicker (the mask pattern for forming a 1, 1, or 2 μm lobe pattern smaller).

Problems to be Solved by the Invention In this way, in the conventional technology, in order to solve the size effect,
There was a problem in that the dimensions of the mask pattern needed to be corrected. The present invention makes it possible to form patterns with a complex mixture of sizes without modifying the dimensions of the pattern 3 of each pattern.

Means for Solving the Problems The present invention solves the above-mentioned problems by forming all mask patterns as a collection of unit rectangular patterns of the same shape in close proximity to each other. The present invention provides a method of exposing a predetermined mask pattern to form a fine pattern with high accuracy regardless of the size of the pattern.

Function The present invention can achieve this by forming all mask patterns into a collection of unit rectangular patterns of the same shape in close proximity to each other.
Regardless of the size of the mask pattern, by making the intensity of light passing through the mask uniform during exposure, a pattern with good pattern size controllability can be formed.

Example An embodiment of the present invention will be described with reference to FIG.

A novolak-based positive photoresist (hereinafter referred to as resist) is applied as a radiation-sensitive resin onto the substrate, and soft baking is performed. Next, 0.5 as unit rectangular pattern 1
A rectangular pattern with a μm opening is placed in a straight line with a distance of 25 μm.
Line pattern 10 lined up, same unit mask pattern 0.
A wavelength of 438 nm was passed through a mask 2o comprising square patterns 11 with 1 and 2 μm openings arranged in four square shapes spaced apart by 2 μm, and a fine square pattern 12 as a single unit pattern.

The resist is exposed using a projection exposure apparatus having an NA of 0.42. Finally, the exposed portion of the resist is developed and removed using a developer. FIG. 2 shows the results of a computer simulation of the relative intensity distribution of light exposed onto the resist. Figure 2(a) shows the relative intensity distribution for the above line pattern 1o.
The square pattern 11 is shown in FIG. 2 (0)), and the fine square pattern 12 is shown in FIG. 2 (C). Note that these calculation results show one half of the pattern in consideration of symmetry. As shown in the figure, the relative intensity of light at the edge of the mask corresponding to each mask pattern is approximately 2,0
As with QE-OI, there is no deviation due to the size of the mask size.

Figures 3(a) to 3(a) on page 5 show a top view of the resist 2 after development. The resist pattern after development for the line pattern 1° is shown in FIG. 3(a), and the resist patterns for the square pattern 11 and the fine square pattern 12 are shown in FIG. 3(b).

and (C). As shown in the figure, the minimum dimension of each pattern was 0.5 μm, and good patterns were formed regardless of the size of the pattern.

Effects of the Invention According to the present invention, it is possible to form a fine fine pattern regardless of the size of the pattern.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a mask and mask pattern according to an embodiment of the present invention, FIG. 2 is a diagram of relative intensity distribution of light exposed through a mask pattern according to the present invention, and FIG. 3 is a top surface of a resist pattern formed according to the present invention. Show the diagram. 1... Unit rectangular pattern, 2o... Mask. Figure 1 2θ mask half (C) /, 2) processing

Claims (1)

[Claims] A process of applying a radiation-sensitive resin onto a substrate, and selectively applying the radiation-sensitive resin through a mask consisting of a graphic pattern formed by closely gathering one or more unit rectangular patterns consisting of minute openings of the same shape. A pattern forming method comprising the steps of exposing to radiation and developing the radiation-sensitive resin.