JPH04264752A - Photomask and manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide a photomask and a manufacturing method for a semiconductor in which formation of a gap at an intersection of a trench can be simply and easily prevented in an improvement in the photomask and a forming method of the trench for isolating elements of a semiconductor device. CONSTITUTION:A photomask of this invention has a pattern corresponding to a pattern of a trench for isolating semiconductor elements on a semiconductor substrate. The trench is formed of an area of an interval of a shielding part 1a of the photomask 1 of an intersection part, formed narrower than the area of the interval of the part 1a of a linear section. The trench is formed on the substrate by photolithography technique by using the photomask 1, and a filling material is filled in the trench.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved photomask and a method for forming trenches for separating elements of a semiconductor device.

[0002] When trenches are formed to separate semiconductor elements on a semiconductor substrate, the interval between the trenches at the intersection of the trenches is wider than the interval between the trenches at the straight part, and when the trenches are filled with a filler material, this interval becomes wider. A problem occurs in which a void is not filled with the filler in a portion corresponding to the difference.

Under the above circumstances, there is a need for a method of manufacturing a semiconductor device that can prevent the formation of voids in the trenches that are not filled with a filler material at the intersections of the trenches.

0004

2. Description of the Related Art Conventional photomasks and semiconductor devices will be explained in detail with reference to FIGS. 5 and 6. FIG. 5 is a diagram showing a pattern of a conventional photomask, and FIG. 6 is a diagram showing a state in which a trench formed in a conventional semiconductor substrate is filled with a filler material.

A pattern corresponding to the intersection of trenches in a conventional photomask 21 is a pattern as shown in FIG. The distance of the farthest part is 1.4142 times W.

When a trench 12a is formed in the semiconductor substrate 12 by photolithography using such a photomask 21, and a filling material 15 made of a silicon oxide film or a polysilicon film is filled in the trench 12a, the structure shown in FIG. As shown, a gap 15a is not filled with the filler at the intersection where the walls of the trench 12a have a wide interval.
occurs.

[0007]

[Problems to be Solved by the Invention] In the conventional semiconductor device described above, when the trench is filled with a filler, the interval between the walls of the trench is wider at the intersection of the trenches than at the straight part. However, there was a problem in that voids were not filled with the filler.

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, an object of the present invention is to provide a photomask and a semiconductor manufacturing method that can simply and easily prevent the formation of voids at the intersections of trenches. It is something.

[0009]

[Means for Solving the Problems] The photomask of the present invention is a photomask provided with a pattern corresponding to a pattern of trenches separating semiconductor elements on a semiconductor substrate, and the photomask is provided with a pattern corresponding to a pattern of trenches separating semiconductor elements on a semiconductor substrate. The area of the interval formed by the pattern of the mask is formed to be smaller than the area of the interval of the pattern of the straight part.

A method for manufacturing a semiconductor device according to the present invention includes a step of laminating an insulating film and a resist film on the surface of a semiconductor substrate, and using the photomask described above, in a method of manufacturing a semiconductor device in which a trench is formed. A step of patterning the resist film of the lever to form an opening window, a step of etching the insulating film using the resist film forming the opening window as a mask to form an opening window, and a step of removing this resist film and forming an opening window. The method includes a step of etching the semiconductor substrate using an insulating film as a mask to form a trench, and a step of removing the insulating film and filling the trench with a filler.

[0011]

[Operation] That is, in the present invention, since it is possible to form the interval between the wall surfaces of the intersection part of the trench formed in the semiconductor substrate at least narrower than the interval of the straight part, the trench is filled with a filler material. In this case, there are no voids that are not filled with the filler, and it becomes possible to reliably fill the trench with the filler.

0012

[Example] Hereinafter, the first embodiment according to the present invention will be described with reference to FIGS. 1 and 2.
A method for manufacturing a semiconductor device according to an embodiment using the photomask according to the first embodiment of the present invention will be explained in detail in the order of steps with reference to FIG. 3.

FIG. 1 is a diagram showing a pattern of a photomask according to a first embodiment of the present invention, and FIG. 2 is a diagram showing a pattern of a photomask according to a second embodiment of the present invention. Figure 1
In the photomask according to the first embodiment of the present invention shown in FIG. A square light shielding portion 1a whose distance is 0.42 times W is formed.

In the photomask according to the second embodiment of the present invention shown in FIG. 2, when the distance between the transparent portions 11b of the linear portions of the photomask 11 in the trench pattern is W, the transparent portions 11b of the trench intersection portions The light shielding part 11a is formed so that the interval between the wall surfaces at the center of the light shielding part 11a is narrower than W.

FIG. 3 is a side sectional view showing a method of manufacturing a semiconductor device according to an embodiment of the present invention in the order of steps. First, Figure 3 (
a) As shown in FIG. 2, an insulating film 3 made of a silicon nitride film or a PSG film is formed on the surface of a semiconductor substrate 2, and a resist film 4 is formed on the surface of this insulating film 3.

Next, as shown in FIG. 3(b), this resist film 4 is patterned using a photomask 1 to form an opening window 4a. Next, as shown in FIG. 3(c), the insulating film 3 is etched using the resist film 4 in which the opening window 4a is formed as a mask to form the opening window 3a.

Thereafter, as shown in FIG. 3(d), the resist film 4 is removed, and the semiconductor substrate 2 is etched using the insulating film 3 in which the opening window 3a is formed as a mask to form a trench 2a.

Finally, as shown in FIG. 4(a), after forming an insulating film as a base on the surface of the semiconductor substrate 2 including the trench 2a, a polysilicon film is grown or a silicon oxide film is directly grown. Then, as shown in FIG. 4B, only the filler 5 above the surface of the semiconductor substrate 2 is removed to finish the surface of the semiconductor substrate 2 into a flat surface.

As described above, since the trench 2a is formed using the photomask 1 or 11 in which the intervals between the patterns corresponding to the trenches 2a are all narrower than the interval W between the trenches 2a in the straight portion, the wall surface of the trench 2a is formed using the photomask 1 or 11. All the intervals are equal to W or less than W, and when the trench 2a is filled with the filler 5, there is no unfilled part, and the trench 2a is reliably filled.
It becomes possible to fill the inside with the filler 5.

[0020]

[Effects of the Invention] As is clear from the above description, according to the present invention, by using a photomask with an extremely simple configuration, it is possible to prevent the formation of voids in the trench that are not filled with filler. It is possible to provide a method for manufacturing a photomask and a semiconductor device that can be expected to significantly improve quality.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a pattern of a photomask according to a first embodiment of the present invention;

FIG. 2 is a diagram showing a pattern of a photomask according to a second embodiment of the present invention;

FIG. 3 is a side sectional view (1) showing a method for manufacturing a semiconductor device according to an embodiment of the present invention in the order of steps;

FIG. 4 is a side sectional view (2) showing a method for manufacturing a semiconductor device according to an embodiment of the present invention in the order of steps;

[Figure 5] Diagram showing the pattern of a conventional photomask,

[Fig. 6] A diagram showing a state in which a filler is filled in a trench formed in a conventional semiconductor substrate.

[Explanation of symbols]

1 and 11 are photomasks, 1a and 11a are light shielding parts; 1b and 11b are transparent parts, 2 is a semiconductor substrate; 2a is a trench, 3 is an insulating film, 3a is an opening window; 4 is a resist film; 4a is an opening window; 5 is a filler;

Claims (2)

[Claims] 1. A photomask comprising a pattern corresponding to a pattern of trenches separating semiconductor elements on a semiconductor substrate, wherein the area of the interval formed by the pattern of the photomask at a portion where the trenches intersect is , a photomask characterized in that the linear portions are formed narrower than the area of the pattern intervals. 2. In a method of manufacturing a semiconductor device in which a trench is formed, an insulating film (3) is formed on a surface of a semiconductor substrate (2).
) and a resist film (4), a step of patterning the resist film (4) using the photomask according to claim 1 to form an opening window (4a), and a step of forming the opening window (4a). Resist film (4) with window (4a) formed
etching the insulating film (3) using the mask as a mask to form an opening window (3a); and etching the resist film (4) as a mask.
) is removed, and the semiconductor substrate (2) is etched using the insulating film (3) as a mask to form a trench (2a).
A method for manufacturing a semiconductor device, comprising the steps of: forming a semiconductor device; and removing the insulating film (3) and filling the trench (2a) with a filler (5).