JPH0620902A - Semiconductor device and manufacture of the same - Google Patents

Abstract

PURPOSE:To inhibit the effect of a charge-up at an extremely small value, and to measure size with high accuracy in the opening section of a resist pattern formed onto a semiconductor substrate when the size is measured by using a sizer, in which a scanning electron microscope is applied. CONSTITUTION:In a pattern for size measurement for measuring the size of the opening section of a resist patter shaped onto a semiconductor substrate, a resist 12 in the periphery of the pattern for size measurement is removed, and the pattern is formed onto a semiconductor substrate in isolated structure without being brought into contact with other resist patterns.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dimension measuring pattern for dimensionally measuring an opening portion of a resist pattern formed on a semiconductor substrate.

[0002]

2. Description of the Related Art A semiconductor device is manufactured through a plurality of photolithography processes. Then, the resist pattern formed on the semiconductor substrate by the photolithography step, that is, the circuit pattern, the etching step which is the next step,
The mask serves as a mask for the ion implantation process, and confirmation of whether or not the dimensions of the resist pattern are formed according to design dimensions is one of the extremely important control items in the manufacture of semiconductor devices.

There are various means for measuring the size of a resist pattern formed on a semiconductor substrate, but at present when the pattern size has entered the submicron region, a size measuring machine to which a scanning electron microscope is applied is used. It is common. FIG. 5 is a diagram illustrating the principle of measuring the diameter dimension of the opening (contact hole) of the resist pattern using a scanning electron microscope. The upper part of Figure 5 is
FIG. 6 is a diagram showing a cross section of a contact hole formed on a semiconductor substrate 52. The resist pattern 51 is formed with a slight taper due to a light diffraction phenomenon during projection exposure, as shown in the figure. The center view of FIG. 5 is a view of the contact hole as viewed from directly above. However, since the resist pattern 51 is tapered as described above, the contact hole appears as a double circle in the scanning electron microscope. The resist pattern 51 can be separated into an upper edge 53 and a lower edge 54. The diameter of the contact hole is generally measured based on the lower edge 54. Next, the lower diagram of FIG. 5 is a diagram in which the intensity distribution of secondary electrons obtained when the contact hole is scanned with an electron beam using a scanning electron microscope is taken out in a certain diameter direction of the contact hole. is there. Since the resist portion 51 and the bottom of the contact hole, that is, the semiconductor substrate 52 portion are made of different materials, the emission rate of secondary electrons is different. Further, since the upper edge 53 of the resist pattern 51 is a portion where the secondary electron emission rate is very high, as shown in the figure, a distribution 55 where the secondary electron intensity has a peak is obtained. Then, in the dimension measurement, the secondary electron intensity distribution 55 is used as a signal waveform to determine the position of the lower edge 53 of the resist pattern 51 based on a predetermined waveform processing algorithm to determine the diameter dimension of the contact hole. Done by.

The principle of dimension measurement using the scanning electron microscope has been briefly described above. Next, the dimension measurement pattern will be described. FIG. 3 is a diagram showing a conventional dimension measuring pattern for measuring the diameter of a contact hole. FIG. 3A shows an example in which a plurality of contact holes 31 are arranged on a scribe line on a semiconductor substrate to form a dimension measuring pattern. In some cases, as in 3 (b), some of the plurality of contact holes 31 formed on the actual element are directly measured. However, in both cases of FIG. 3A and FIG. 3B, the periphery of the contact hole 31 has a structure in which the entire surface is covered with the resist.

[0005]

However, the above-mentioned prior art has the following problems.

The resist material is an insulator. Therefore, when the electron beam is scanned, the charge is accumulated in the resist, causing a phenomenon called charge-up. This phenomenon occurs when measuring dimensions using a scanning electron microscope.
This not only disturbs the secondary electron image of the observed resist pattern, but also significantly deteriorates the accuracy of dimension measurement. FIG. 4 is a diagram showing a signal waveform when a diameter dimension of a contact hole is measured by using a conventional dimension measurement pattern under a charge-up phenomenon, that is, a secondary electron intensity distribution. Is. The upper view of FIG. 4 is a view of the contact hole as viewed from directly above. As described above, the resist pattern 41 is divided into the upper edge 42 and the lower edge 43, and is observed as a double circle. As expected, the intensity distribution 44 of the secondary electrons obtained when the electron beam is scanned is greatly disturbed by the effect of charge-up, and as shown in the lower diagram of FIG. Is a signal waveform 44 lacking in sharpness and very difficult to identify. In this state, the observed secondary electron image lacks sharpness, and the pattern edge of the contact hole is also very unclear. Therefore, the dimensional measurement reproducibility is usually 0.02 μm (3σ).
Although it is at the level, it is significantly deteriorated to 0.05 μm (3σ). As described above, when the dimension of the opening portion of the resist pattern is measured, in the conventional dimension measuring pattern, since the periphery of the pattern is entirely covered with the resist, the influence of charge-up is particularly strong, and the dimension measuring accuracy is high. Is greatly deteriorated.

Therefore, the present invention is to solve such a problem, and an object of the present invention is to measure the opening portion of a resist pattern formed on a semiconductor substrate by using a dimension measuring instrument to which a scanning electron microscope is applied. An object of the present invention is to provide a semiconductor device provided with a pattern for dimension measurement which can suppress the influence of charge-up as much as possible and measure with high dimension measurement accuracy when the dimension is measured by using, and a manufacturing method.

[0008]

[Means for Solving the Problems] 1. In the semiconductor device of the present invention, in the dimension measuring pattern for dimension measuring the opening portion of the resist pattern formed on the semiconductor substrate, the resist around the dimension measuring pattern is removed and the resist pattern contacts another resist pattern. It is characterized in that it is formed separately on the semiconductor substrate without being formed.

2. According to the method of manufacturing a semiconductor device of the present invention, when the dimension of the opening portion of the resist pattern formed on the semiconductor substrate is measured, the first semiconductor device is formed on the semiconductor substrate.
It is characterized by using a dimension measuring pattern having the structure described in the item.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 (a) is a view showing the structure of a dimension measuring pattern portion of the present invention. In the present invention, a dimension measuring pattern for measuring the diameter dimension of the contact hole is provided on the scribe line of the semiconductor substrate, and the pattern shown in FIG.
As shown in (a), a plurality of contact holes 1
1 was arranged and the resist 12 around it was removed to form an isolated structure without contacting with other resist patterns.

FIG. 1 (b) shows that when a dimension measuring machine to which a scanning electron microscope is applied is used to scan an electron beam on the dimension measuring pattern of the present invention, it accumulates in the resist over time. It is a figure which shows the result of having measured the electric charge and compared with the conventional pattern for dimension measurement. The tendency that the amount of charge accumulated in the resist increases with the lapse of time is the same in the present invention and the conventional one, but in the dimension measuring pattern of the present invention, the resist around the pattern is removed. Since the structure is isolated without contacting other resist patterns, the amount of accumulated charges can be suppressed to less than half compared to the conventional dimension measurement pattern, and it is possible to minimize charge-up. became.

FIG. 2 shows a signal waveform when the diameter dimension of a contact hole is measured by a dimension measuring instrument to which a scanning electron microscope is applied, that is, the intensity distribution of secondary electrons, using the dimension measuring pattern of the present invention. FIG. The top view of FIG. 2 is a view of the contact hole as viewed from directly above. However, due to the above-mentioned reason, the charge-up is greatly reduced, and therefore the upper edge 22 and the lower edge 23 of the resist pattern 21 are A secondary electron image clearly separated is obtained. Therefore, the intensity distribution 24 of the secondary electrons taken out in a certain diameter direction of the contact hole has a very sharp signal waveform as shown in the lower diagram of FIG. 2, and the dimensional measurement reproducibility is 0.02 μm (3σ). ), And was able to achieve high accuracy. As described above, according to the present embodiment, when the opening portion of the resist pattern formed on the semiconductor substrate is measured using a dimension measuring machine to which a scanning electron microscope is applied, charge-up is suppressed as small as possible,
It is possible to measure with high dimensional measurement accuracy.

The embodiment of the present invention has been described above. In addition to the above, 1) In the case of measuring not only the contact hole but also the width of the elongated groove pattern.

2) When measuring the dimension of the opening of the resist pattern formed on the quartz glass substrate in addition to the semiconductor substrate.

3) In the case of measuring an opening portion of a pattern formed by a material such as silicon oxide or silicon nitride, which is an insulator and thus easily causes charge-up, in addition to the resist.

As described above, in each case, the same effect as that of this embodiment can be expected.

[0017]

As described above, according to the present invention, 1. In the dimension measurement pattern for dimension measurement of the opening portion of the resist pattern formed on the semiconductor substrate, the resist around the dimension measurement pattern is removed, without contact with other resist patterns, isolated It is formed on the semiconductor substrate.

2. When the dimension of the opening portion of the resist pattern formed on the semiconductor substrate is measured, the dimension measuring pattern having the structure according to the first aspect formed on the semiconductor substrate is used.

As a result, when the opening portion of the resist pattern formed on the semiconductor substrate is dimensionally measured using a dimension measuring machine to which a scanning electron microscope is applied, the influence of charge-up is suppressed to a minimum, and a high dimension is achieved. This makes it possible to perform measurement with measurement accuracy, and has the effect of maintaining high quality in the manufacture of semiconductor devices.

[Brief description of drawings]

FIG. 1A is a diagram showing a structure of a dimension measuring pattern of the present invention. (B) When a scanning electron microscope is used to scan the electron beam on the pattern for dimension measurement of the present invention using a dimension measuring instrument to which a scanning electron microscope is applied, the amount of charge accumulated in the resist with the passage of time is measured. It is a figure which shows the result compared with the pattern for dimension measurement of.

FIG. 2 is a diagram showing a signal waveform when the diameter dimension of a contact hole is measured by a dimension measuring machine to which a scanning electron microscope is applied using the dimension measuring pattern of the present invention.

FIG. 3A is a diagram showing a conventional dimension measurement pattern in which a plurality of contact holes are arranged on a scribe line of a semiconductor substrate. (B) It is a figure which shows the contact hole formed on the actual element of a semiconductor substrate.

FIG. 4 is a signal obtained by measuring the diameter dimension of a contact hole using a conventional dimension measurement pattern under a charge-up phenomenon by a dimension measuring instrument to which a scanning electron microscope is applied. It is a figure which shows a waveform.

FIG. 5 is a diagram illustrating the principle of measuring the diameter dimension of the opening portion (contact hole) of the resist pattern formed on the semiconductor substrate using a dimension measuring machine to which a scanning electron microscope is applied.

[Explanation of symbols]

 11. ． ． Contact hole 12. ． ． Resist 21. ． ． Resist 22. ． ． Upper edge of resist pattern 23. ． ． Lower edge of resist pattern 24. ． ． Signal waveform (intensity distribution of secondary electrons) 31. ． ． Contact hole 32. ． ． Resist 41. ． ． Resist 42. ． ． Upper edge of resist pattern 43. ． ． Lower edge of resist pattern 44. ． ． Signal waveform (intensity distribution of secondary electrons) 51. ． ． Resist 52. ． ． Semiconductor substrate 53. ． ． Upper edge of resist pattern 54. ． ． Lower edge of resist pattern 55. ． ． Signal waveform (intensity distribution of secondary electrons)

Claims (2)

[Claims] 1. In a dimension measuring pattern for dimension measuring an opening portion of a resist pattern formed on a semiconductor substrate, the resist around the dimension measuring pattern is removed and it does not come into contact with other resist patterns. And a semiconductor device formed on the semiconductor substrate in an isolated manner. 2. A dimension measuring pattern having a structure according to claim 1, which is formed on the semiconductor substrate, when the dimension of an opening portion of a resist pattern formed on the semiconductor substrate is measured. Of manufacturing a semiconductor device.