JPH08321532A - Inspection method of position deviation of alignment mark - Google Patents

Abstract

PURPOSE: To simplify confirmation work of position deviation of mutual alignment marks. CONSTITUTION: When a second reticle 10 is positioned above a silicon substrate 4 in which first patterns are formed, alignment marks 12 on the second reticle 10 are positioned as a form concentrated at a central side of matrix arrangement of the first patterns. Since dimension from an end of the first pattern to the outer peripheral part of the alignment mark 12 of the second reticle 10 is comparatively lengthened, position deviation of the pattern and the mark is easily inspected by using visual observation or a simple microscope.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting alignment mark misalignment in lithography technology.

[0002]

14 to 18 showing the alignment mark alignment process in the process of forming a contact hole after forming a LOCOS oxide film on, for example, a silicon substrate in the process of manufacturing a semiconductor device according to this conventional technique. It will be explained based on FIG. 14 shows a part of the first reticle 51 for the LOCOS process, and an outer frame 52 made of a transparent glass surface.
And a registration mark 53 composed of a chrome surface is formed.

Reference numeral 54 shown in FIG. 15 is a silicon substrate, which is made of Si.
A resist film 57 is formed on the O2 film 55 and the Si3 N4 film 56. When the resist film 57 is irradiated with light through the first reticle 51 and developed, light is emitted through the glass surface as shown in FIG. The resist film 57 in the irradiated portion is removed, and the alignment mark 53 is transferred onto the silicon substrate 54.

Next, using the resist film 57 as a mask, S
After the i3N4 film 56 and the SiO2 film 55 are etched, the resist film 57 is removed, and as shown in FIG. 16, thermal oxidation is performed to form a LOCOS oxide film 58, the Si3N4 film 56 and the SiO2 film 55 are removed, and gate oxidation is performed. The film 59 is formed. FIG. 17 shows a part of the second reticle 60 for the contact process, which includes an outer frame 61 made of a transparent glass surface.
And a registration mark 62 composed of a chrome surface is formed.

FIG. 18 shows a state in which the reticle 60 is located above the substrate 54. An operator sets a gap (L1) between the end of the LOCOS oxide film 58 and the end of the alignment mark 62 from above the substrate 54. By visual inspection, the L
It was confirmed whether the alignment marks of the first reticle 51 used for forming the OCOS oxide film and the second reticle 60 used for forming the contact hole were misaligned.

However, due to the difference in conversion in the wafer process, the alignment mark composed of the pattern formed on the substrate 54 using the first reticle 51 and the second reticle 60.
If the gap with the alignment mark above becomes narrow, it is not possible to confirm whether or not the manufacturing process can be continued using this alignment mark by visual inspection or using a simple microscope, or it is troublesome and troublesome. . On the contrary, if the gap is wide, the alignment accuracy is lowered. Therefore, it is difficult to set the optimum gap.

[0007]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to simplify the work of confirming the positional deviation between alignment marks.

[0008]

In view of the above, the present invention uses a first reticle in which a plurality of rectangular alignment marks of the same size corresponding to the first step are arranged in rows and columns on a glass surface, and a first reticle is formed on a silicon substrate. After forming the pattern No. 1, the same number of rectangular alignment marks smaller than the alignment marks corresponding to the second step were arranged in a matrix on the glass surface so as to gather on the center side of the alignment marks. A gap between the end of the first pattern formed on the silicon substrate and the outer peripheral portion of the alignment mark of the second reticle is inspected through the glass surface of the second reticle.

Further, the present invention uses a first reticle in which a plurality of rectangular alignment marks of the same size corresponding to the first step are arranged in rows and columns on a glass surface to form a first reticle on a silicon substrate.
After forming the pattern, the same number of rectangular alignment marks smaller than the alignment marks corresponding to the second step are arranged in a matrix on the glass surface so as to gather on the center side of the alignment marks. A second reticle is used to form a second pattern on the silicon substrate.
Then, a gap is inspected from the end of the first pattern formed on the substrate to the outer peripheral portion of the second pattern formed in a state of being gathered on the center side of the first pattern. .

[0010]

With the above structure, when the second reticle is positioned above the silicon substrate on which the first pattern is formed, the second reticle is gathered on the center side of the matrix arrangement of the first pattern. Since the alignment mark on the reticle is located, the dimension from the edge of the first pattern to the outer periphery of the alignment mark of the second reticle is relatively wide, so that the pattern and the mark can be visually or visually inspected with a simple microscope. Misalignment is easily inspected.

Since the second pattern is formed in a form gathered on the center side of the matrix arrangement of the first pattern, the first pattern is formed.
Since the dimension from the edge of the pattern to the outer peripheral portion of the second pattern is relatively wide, the positional deviation between the patterns can be easily inspected by visual inspection or even by a simple microscope inspection.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 1 showing a process of aligning alignment marks in a process of forming a contact hole after forming a LOCOS oxide film on, for example, a silicon substrate in a process of manufacturing a semiconductor device. It will be described in detail based on 6. FIG. 1 shows a part of a first reticle 1 for the LOCOS process, in which an outer frame 2 made of a glass surface and four relatively large rectangular alignment marks 3 made of a chrome surface are arranged in a matrix. .

Reference numeral 4 shown in FIG. 2 is a silicon substrate.
A SiO2 film 5 and a Si3 N4 film 6 are laminated on top of this, and a resist film 7 is formed thereon. And the first
By irradiating light through the reticle 1 and then developing, the resist film 7 in the portion irradiated with light is removed as shown in FIG. As a result, the alignment mark 3 is transferred onto the silicon substrate 4.

Next, using the resist film 7 as a mask, Si
After etching the 3N4 film 6 and the SiO2 film 5, the resist film 7 is removed, and thermal oxidation is performed as shown in FIG.
An S oxide film 8 is formed, the Si3 N4 film 6 and the SiO2 film 5 are removed, and a gate oxide film 9 is formed. FIG. 4 shows a part of the second reticle 10 for forming a contact, and includes an outer frame 11 made of a glass surface and a chrome surface (somewhat smaller than the alignment mark 3 of the first reticle 1, which will be described later). Alignment mark 12 consisting of four rectangular shapes of the same size whose center is off the center of alignment mark 3
And are formed.

FIG. 5 is a state view (plan view) in which the second reticle 10 is positioned above the substrate 4, and an operator works from above the reticle 10 to the edge of the LOCOS oxide film 8 and the reticle 1.
By visually inspecting the gap up to the outer peripheral portion of the alignment mark 12 above 0, the first pattern formed using the first reticle 1 used for forming the LOCOS oxide film and the contact hole for forming the contact hole are formed. Whether or not the alignment mark on the second reticle 10 to be used is displaced is confirmed.

At this time, the centers of the alignment marks 12 arranged in a matrix of the second reticle 10 are formed so as to gather at the centers of the alignment marks 3 arranged in a matrix of the corresponding first reticle 1. Therefore, the gap (L2) between the end of the LOCOS oxide film 8 and the outer peripheral portion of the alignment mark 12 when viewed through the glass surface of the second reticle is the outer periphery as compared to the center side of the matrix arrangement as shown in FIG. The side is wide. Therefore, the operator can easily see the gap (L
The presence or absence of positional deviation due to the alignment mark can be easily determined only by visually inspecting whether or not 2) are at substantially equal intervals or by inspecting with a simple microscope. In this embodiment, as shown in FIG. 5, it is normal if the gap (L2) between the end of the LOCOS oxide film 8 formed on the substrate 4 and the alignment mark 12 on the second reticle 10 is equal. If it is different, it is determined to be abnormal. If it is determined to be abnormal, realign the alignment mark.

Next, as another embodiment, FIG. 6 to FIG. 10 showing a process of aligning alignment marks in a process of forming a contact hole after forming a gate electrode in, for example, a silicon substrate in a process of manufacturing a semiconductor device. Explained. FIG. 6 shows a part of the first reticle 21 for the gate electrode forming step, in which an outer frame 22 made of a glass surface and six relatively large rectangular alignment marks 23 of the same size made of a chrome surface are arranged in a matrix. ing.

Reference numeral 24 shown in FIG. 7 is a silicon substrate, on which a SiO2 film 25 and a polysilicon layer are laminated, and a resist film (not shown) is formed thereon. Then, by irradiating with light through the mask 21 and then developing, the resist film in the portion irradiated with light is removed. As a result, the alignment mark 23 is changed to the silicon substrate 24.
Transcribed on.

Next, the polysilicon layer is etched using the resist film as a mask to form the gate electrode 26, and then the resist film is removed (see FIG. 7). FIG. 8 shows a part of the second reticle 27, which includes an outer frame 28 made of a glass surface and a chrome surface (somewhat smaller than the alignment mark 23 of the first reticle 21, and its center is aligned as described later). The alignment mark 29 is formed of six rectangular shapes of the same size that are off the center of the mark 23.

FIG. 9 shows the substrate 2 on which the first pattern is formed.
4 is a state diagram (plan view) in which the second reticle 27 is positioned above the upper portion of FIG. By inspecting with a microscope,
It is confirmed whether the first pattern formed by the first reticle 21 used for forming the gate electrode and the alignment mark 29 on the second reticle 27 used for forming the contact hole are displaced.

At this time, as in the first embodiment, the centers of the alignment marks 29 arranged in a matrix of the second reticle 27 are aligned with the centers of the alignment marks 23 arranged in a matrix of the corresponding first reticle 21. Since they are formed so as to gather together, the gap (L3) between the end of the gate electrode 26 and the outer peripheral portion of the alignment mark 29 is wider on the outer peripheral side than on the central side of the matrix arrangement as shown in FIG. Therefore, the operator can easily determine the presence or absence of the positional deviation due to the alignment mark only by visually inspecting or visually inspecting whether or not the easily visible gaps (L3) are substantially equal intervals. In this embodiment, as shown in FIG.
If the gap (L3) between the end of the gate electrode 26 formed above and the outer periphery of the alignment mark 29 is all equal, it is normal, and if they are different, it is abnormal.

As described above, according to the present invention, for example, the step of forming the contact hole with the LOCOS oxide film 8 on the silicon substrate 1 by the alignment mark 3 and the alignment mark 12, and the silicon substrate 21 including the gate electrode 26 and the contact hole. When inspecting whether or not the alignment process using the alignment mark 23 and the alignment mark 29 at the time of forming is normally performed, the matrix arrangement of the alignment marks 12 and 29 of the second reticles 10 and 27 corresponds to the corresponding alignment mark. Since the alignment marks 3 and 23 of the first reticle 1 and 21 are formed so as to be gathered at the center of the matrix arrangement, as shown in FIG. 5 and FIG. L2, L
Whether or not there is a positional shift due to these alignment marks can be easily determined only by checking whether or not 3) is at substantially equal intervals.

Further, the present invention can be applied to other than the above-mentioned matching step. Further, in this embodiment, the first silicon substrate is used.
After the pattern is formed, the alignment state is confirmed by inspecting the gap between the pattern and the alignment mark on the second reticle. For example, the second reticle is used to make a first alignment on the substrate. After forming the pattern of 2,
Similarly, the gap between the patterns may be inspected to check whether or not the alignment work is performed well.

That is, after laminating the interlayer insulating film 13 and the resist film 14 on the substrate 4 in the first embodiment,
After the predetermined resist film 14 is removed by irradiating light through a reticle (not shown), the interlayer insulating film 13 is etched by using the remaining resist film 14 as a mask to form the contact hole 1
5 is formed (see FIG. 10). Then, the worker is shown in FIG.
As shown in FIG. 5, the first reticle for forming the LOCOS oxide film and the second reticle for forming the contact hole are visually inspected from above the substrate 4 by visually inspecting the gap (L2) between the end of the LOCOS oxide film 8 and the contact hole 15. You can check the alignment mark using the reticle.

Similarly, in the second embodiment, the gate electrode 2
After the interlayer insulating film 30 and the resist film 31 are laminated on the substrate 24 after the formation of 6, the predetermined resist film 31 is removed by irradiating light through a reticle (not shown), and the remaining resist film 31 is removed. Using as a mask, the interlayer insulating film 30 is etched to form a contact hole 32 (see FIG. 12).

Then, the operator visually inspects the gap (L3) between the gate electrode 26 and the contact hole 32 from above the substrate 24 as shown in FIG. 13 to make contact with the first reticle for forming the LOCOS oxide film. Second for hole formation
You can check if there is any misalignment of the alignment mark using the reticle.

[0027]

As described above, according to the present invention, since the alignment marks on the second reticle are formed so as to be gathered on the center side of the alignment marks on the first reticle, the first reticle is used. By locating the second reticle above the silicon substrate on which the pattern is formed and seeing the first pattern through the glass surface of the second reticle, the alignment mark of the second reticle can be seen from the end of the first pattern. Since the dimension up to the outer peripheral portion is relatively wide, the positional deviation between the pattern and the alignment mark can be easily inspected visually, and highly accurate alignment work using the alignment mark becomes possible.

In addition, after forming the first pattern on the silicon substrate using the first reticle corresponding to the first step, the alignment marks are arranged in a matrix on the second reticle corresponding to the second step. Since the second pattern is formed through the same number of rectangular alignment marks smaller than the alignment marks arranged in a matrix on the glass surface so as to gather on the center side, the second pattern is the first pattern. Since the shape is gathered on the center side of the matrix arrangement and the dimension from the end of the first pattern to the outer peripheral portion of the second pattern is relatively wide, the misalignment between the patterns can be easily inspected visually and the alignment mark This enables highly accurate alignment work.

[Brief description of drawings]

FIG. 1 is a diagram showing a first reticle used in the present invention.

FIG. 2 is a cross-sectional view showing the manufacturing process of the semiconductor device using the first reticle.

FIG. 3 is a cross-sectional view showing the manufacturing process of the semiconductor device using the first reticle.

FIG. 4 is a diagram showing a second reticle.

FIG. 5 is a state diagram when a second reticle is positioned above a silicon substrate.

FIG. 6 is a diagram showing a first reticle of another embodiment.

FIG. 7 is a cross-sectional view showing a manufacturing process of a semiconductor device using a first reticle of another embodiment.

FIG. 8 is a diagram showing a second reticle of another embodiment.

FIG. 9 is a state diagram when a second reticle is positioned above a silicon substrate of another embodiment.

FIG. 10 is a cross-sectional view showing a manufacturing process of a semiconductor device in which a contact hole is formed after forming a LOCOS oxide film.

FIG. 11 is a plan view showing a silicon substrate having a contact hole formed therein.

FIG. 12 is a cross-sectional view showing a manufacturing process of a semiconductor device in which a contact hole is formed after forming a gate electrode.

FIG. 13 is a plan view showing a silicon substrate having a contact hole formed therein.

FIG. 14 is a diagram showing a first reticle of a conventional example.

FIG. 15 is a cross-sectional view showing the manufacturing process of the semiconductor device using the first reticle of the conventional example.

FIG. 16 is a cross-sectional view showing the manufacturing process of the semiconductor device using the first reticle of the conventional example.

FIG. 17 is a diagram showing a second reticle of a conventional example.

FIG. 18 is a diagram showing a state in which a second reticle is located above a conventional silicon substrate.

Claims (2)

[Claims] 1. A first structure in which a plurality of rectangular alignment marks of the same size corresponding to the first process are arranged in a matrix on a glass surface.
Of forming the first pattern on the silicon substrate using the reticle of the above, and the same number of rectangular alignment marks smaller than the alignment marks corresponding to the second process are provided on the center side of the alignment mark matrix arrangement. The gap from the end of the first pattern formed on the silicon substrate to the outer periphery of the alignment mark of the second reticle is inspected through the glass surface of the second reticles arranged in a matrix so as to gather. A method for inspecting alignment mark misalignment, which comprises: 2. A step of forming a first pattern on a silicon substrate using a first reticle in which a plurality of rectangular alignment marks of the same size corresponding to the first step are arranged in rows and columns; A second pattern is formed on a silicon substrate by using a second reticle arranged in a matrix so that rectangular alignment marks of the same number smaller than the alignment marks corresponding to the process are gathered on the center side of the matrix arrangement of the alignment marks. And a step of inspecting a gap from the end of the first pattern formed on the silicon substrate to the outer peripheral portion of the second pattern formed in a state of being gathered on the center side of the first pattern. A method for inspecting a positional deviation of a registration mark, comprising: