JPH06151372A - Etching mask pattern and dry etching method - Google Patents

Abstract

PURPOSE:To readily detect end point of etching at a plurality of times in the etching using the end point detection. CONSTITUTION:As a pattern layout of a scribe line region 1, a part 2 opening at etching at the first time and a part 3 opening at etching at the second time are formed. Thus, etching is performed by dividing the scribe line region. whereby end point detection can readily be performed by a plurality of etchings.

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 semiconductor device, and more particularly to a mask pattern used for etching for detecting an end point, particularly for contact hole etching.

[0002]

2. Description of the Related Art In recent years, semiconductor devices have been miniaturized and DRAM
The number of times of etching is increasing in the manufacturing process as represented by. For example, stack cell type DRAM
Then, it is necessary to etch the bit line contact, the storage node contact, the aluminum wiring contact, etc. three times or more for the etching of the contact hole with respect to the silicon substrate.

When performing normal etching, two methods are used. One is a case where the etching time is determined, and the second is a case where the emission spectrum intensity from the gas in the etching atmosphere is monitored and the etching end point is detected for each one by the change. In the case of the second method, the emission spectrum corresponding to the material to be etched is selected and monitored, but the end point cannot be detected unless sufficient emission spectrum intensity and change in the emission spectrum intensity occur. This is because it is affected by various noises. For example, generally, when etching an oxide film using silicon as a substrate, the emission spectrum of CO is detected. In this case, when the oxide film is being etched, O is supplied from the oxide film, and the emission spectrum intensity of C—O is high. When the etching is completed and the silicon of the substrate is exposed, the supply of O is reduced and the emission spectrum intensity of C—O is lowered. By detecting this change, the etching end point of the oxide film is detected.

An example of a conventional method for manufacturing the above-described semiconductor device will be described below with reference to the drawings.

FIG. 4 is a process sectional view showing a first conventional DRAM manufacturing method. First, in FIG. 4A, after forming the first oxide film 5 on the silicon substrate 4, the first resist mask 11 having only the first contact hole opened is formed.
Reference numeral 15 denotes a so-called scribe line area, which is an area (chip division area) for cutting and dividing the chip.

In FIG. 4b, using the first resist mask 11 as a mask, the first oxide film 5 is subjected to known conditions, for example, CHF3 is used as a gas, and RF of 13.56 MHz is applied under a pressure of 100 Pa.
Is dry-etched under the condition that 500 W is applied. In this case, the aperture ratio is about 3%. Therefore, the supply of the light emitting element from the material to be etched or the consumption of the light emitting element to the material to be etched is small. For this reason, it is difficult to detect the end point because sufficient emission spectrum intensity cannot be obtained. Therefore, only the method other than the end point detection, for example, the etching by fixing the time can be performed. Therefore, this etching cannot absorb variations in the thickness of the first oxide film 5 and variations in the etching rate, so that stable etching cannot be performed.

In FIG. 4c, after removing the first resist mask 11, the first wiring 7 is formed and the second oxide film 8 is deposited. After that, the second resist 12 having the second contact hole and the scribe line region opened is formed.

In FIG. 4d, dry etching is performed in the same manner as in FIG. 4b using the second resist 12 as a mask. At this time, the opening ratio is 15% or more because the scribe line region is opened. In this case, since the aperture ratio is large, a sufficient emission spectrum intensity can be obtained, and the etching can be performed by using the end point detection method.

In FIG. 4e, the second wiring 10 is formed after removing the second resist 12. FIG. 5 shows a second conventional
FIG. 6 is a process cross-sectional view showing the method of manufacturing a DRAM.

An example of a second conventional method of manufacturing a semiconductor device using the above-mentioned etching mask pattern will be described with reference to FIG.

First, in FIG. 5a, a first oxide film 5 is formed on a silicon substrate 4, and a first resist 13 having a first contact hole and a scribe line region opened is formed. Reference numeral 15 indicates a scribe line area.

In FIG. 5B, dry etching is performed under the well-known conditions using the first resist 13 as a mask, for example, using CHF3 as a gas and applying RF of 13.56 MHz at 500 W under a pressure of 100 Pa. At this time, since the scribe line region is opened, the aperture ratio is 15% or more, sufficient emission spectrum intensity is obtained, and etching can be performed using the end point detection method.

In FIG. 5c, after removing the first resist 13, the first wiring 7 is formed and the second oxide film 8 is deposited. After that, the second resist 14 having the second contact hole and the scribe line region opened is formed.

In FIG. 5d, dry etching is performed in the same manner as in FIG. 5b using the second resist mask 14 as a mask.
At this time, the aperture ratio is about 15%, and a large emission spectrum signal can be obtained. However, this emission spectrum signal is information of only the second oxide film 8, and at the time when this emission spectrum signal is obtained, the contact hole portion is still in the middle of etching. Therefore, a sufficiently effective end point detection is impossible.

In FIG. 5e, the second wiring 10 is formed after removing the second resist 14.

[0016]

With the above-mentioned structure, only one contact hole etching can obtain a sufficient and effective emission spectrum signal for end point detection by opening simultaneously with the scribe line region. However, the contact hole etching has a problem that it is difficult to detect the end point because a sufficient emission spectrum signal intensity cannot be obtained.

In view of the above problems, the present invention provides an etching mask pattern and an etching method for easily detecting an end point in a plurality of times of etching.

[0018]

In order to solve the above problems, the etching mask pattern of the present invention has a structure having a contact hole and a part where both of the scribe line regions are opened. The etching method of the present invention is an etching method of detecting an end point using the mask pattern.

[0019]

According to the present invention, by dividing the scribe line region by the above-mentioned structure, the region to be etched is increased in each of a plurality of etchings.
Therefore, the supply of the light emitting element from the material to be etched or the consumption of the light emitting element to the material to be etched is increased. Therefore, in the etching using the mask pattern of the present invention, it becomes possible to detect the end point in which the emission spectrum signal intensity is effective every time.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An etching mask pattern according to an embodiment of the present invention will be described below with reference to the drawings. In particular, the case where the etching is performed twice is shown.

FIG. 1 shows a pattern layout of a scribe line region of an etching mask pattern in an embodiment of the present invention. In FIG. 1, 1 is a scribe line region, 2 is a portion opened during the first etching, and 3 is a portion opened during the second etching.

2A to 2D show process cross sections in an embodiment of the present invention. An example of a method of manufacturing a semiconductor device using the above etching mask pattern will be described with reference to FIG.

First, in FIG. 2a, a first oxide film 5 is formed on a silicon substrate 4, and a first resist mask 6 is formed by opening a first contact hole and a part of a scribe line region. Reference numeral 15 indicates a scribe line area.

In FIG. 2b, the first resist mask 6 described above is used.
Well known conditions as a mask, for example, CHF3 as a main component as a gas, RF of 13.56MHz at a pressure of 100Pa 500W
Dry etching is performed under the applied conditions. At this time, the opening ratio is 1 because part of the scribe line area is opened.
It becomes 0% or more. When the emission spectrum of CO is detected as the end point detection, a large emission spectrum signal is obtained while etching the oxide film, and the emission spectrum signal becomes small when the etching of the oxide film is completed. Therefore, a large emission spectrum signal change can be obtained. Therefore, it is possible to perform etching using the end point detection method.

In FIG. 2c, after removing the first resist mask 6, a first wiring 7 is formed and a second oxide film 8 is deposited. After that, a second resist mask 9 is formed in which the second contact hole and a portion of the scribe line region which is not opened by the first resist mask 6 are opened.

In FIG. 2d, dry etching is performed in the same manner as in FIG. 2b using the second resist mask 9 as a mask. Also in this case, since the opening of a part of the scribe line region is made, the aperture ratio becomes 10% or more, and similar to the first dry etching, sufficient emission spectrum intensity and emission spectrum signal change are obtained, and the end point detection is performed. It is possible to etch using the method.

In FIG. 2e, the second wiring 10 is formed after removing the second resist 9. As described above, according to this embodiment, at the time of etching each contact hole,
By providing the opening by dividing the scribe line region, effective end point detection can be performed because effective and sufficient emission spectrum intensity and large emission spectrum signal change are obtained in each etching.

In this embodiment, the contact etching for the wiring is used, but it goes without saying that it may be used for the contact etching of the storage node. It is also clear that it is effective for etching other than the contact hole.

Further, in the present embodiment, the emission spectrum intensity of CO was used for the end point detection, but other emission spectra, for example,
You may use F etc.

Further, although the etching of the oxide film has been described in the present embodiment, it is obvious that the present invention can be applied to the etching of other kinds of films.

Further, in the present embodiment, the division of the scribe line area is made so as not to overlap each other, but even if they overlap as shown in FIG.
There may be a portion which is not etched on the scribe line region as described above.

Although the foregoing invention has been described in detail by way of illustration and example method for clarity of understanding, it will be apparent that certain changes and modifications can be made to the appended claims.

[0033]

As described above, according to the present invention, by providing the contact hole and the portion in which part of the scribe line region is opened, it is possible to effectively detect the end point in each of a plurality of etchings. it can.

[Brief description of drawings]

FIG. 1 is a pattern layout diagram on a scribe line region of an etching mask pattern in an example of the present invention.

FIG. 2 is a process cross-sectional view of a method for manufacturing a semiconductor device when using an etching mask pattern in the example.

FIG. 3 is a pattern layout diagram on another scribe line area in the example.

FIG. 4 is a process cross-sectional view showing the first conventional DRAM manufacturing method.

FIG. 5 is a process cross-sectional view showing the second conventional DRAM manufacturing method.

[Explanation of symbols]

1 scribe line region 2 part of scribe line region opened during the first etching 3 part of scribe line region opened during the second etching

Claims (3)

[Claims] 1. An etching mask pattern for forming the same device, wherein an etching mask pattern is provided in at least two or more kinds of masks and has an opening portion divided into chip division regions. 2. A mask pattern for etching, wherein the etched region according to claim 1 is used as a contact hole. 3. In an etching mask for forming the same device, end point detection is performed by using an etching mask pattern having an area to be etched and an opening portion divided into chip division areas in at least two kinds of masks. Dry etching method.