JPH02273954A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To detect the position deviation of a resist film even in the case where a main body element whose position deviation allowance is smaller than margin is present, by arranging a window coinciding with the ion implantation region of a monitor element, in a resist film used as an ion implantation mask for the main body element. CONSTITUTION:For a substrate 1 forming a main body element, the ion implantation region of a monitor element is defined by a film on the substrate 1. A window 6a coinciding with the ion implantation region of a monitor element is arranged in a resist film 5, and ion is implanted, thereby forming the monitor element. After that, electric characteristics of the monitor element are measured, thereby detecting the position deviation of the resist film 5. That is, the ion implantation region is masked by the amount of position deviation of the resist film 5, and the diffusion region formed by ion implantation is narrowed by that amount, so that the position deviation of the resist film can be detected by making the monitor element reflect the narrowing of the diffusion region on the characteristics.

Description

[Detailed Description of the Invention] [Summary] Regarding a method of manufacturing a semiconductor device, the present invention aims to provide a method for detecting a positional shift of a resist film used as a mask for ion implantation of a main body element constituting a semiconductor device. The step of defining the ion implantation region of the monitor element with a film on the substrate, and the process of defining the ion implantation region of the monitor element in a resist film used as a mask for the ion implantation of the main body element so as to match the ion implantation region of the monitor element. forming a monitor element including the step of providing a window and performing the ion implantation;
Thereafter, the electrical characteristics of the monitor element are measured to detect the positional deviation of the resist film, and the ion implantation region of the monitor element is placed on the substrate forming the main body element. A second resist film used as a mask for the ion implantation of the one conductivity type of the main body element is provided with a window exposing the entire area of the ion implantation region of the monitor element, and the ion implantation of the one conductivity type is performed. In addition, a second resist film used as a mask for the opposite conductivity type ion implantation of the main body element is provided with a window whose edges should match each other outside the ion implantation area of the monitor element, and the opposite conductivity type ion implantation is performed. The method is configured to form a monitor element, and then measure the electrical characteristics of the monitor element to detect a positional shift of the second resist film.

(Industrial Application Field) The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of detecting, using a monitor element, a positional shift of a resist film used as a mask for ion implantation of a main body element constituting a semiconductor device. .

In the manufacture of semiconductor devices, photolithography is often used in which a resist film is provided on a substrate, a pattern is formed on the resist film by exposure, and the substrate is processed using the resist film as a mask.

The above-mentioned ion implantation is also part of this process. In some semiconductor devices, the element may be formed defectively if the position of the diffusion region relative to the substrate is excessively shifted due to ion implantation.In this case, the position shift of the diffusion region is detected and, if necessary, measures are taken to reduce the position shift. It is necessary to take measures to prevent the production of defective products.

Although it is difficult to detect the displacement of the diffusion region by observing the diffusion region itself, it can be performed by detecting the displacement of a resist film used as a mask for ion implantation. The present invention utilizes a monitor element to detect positional deviation of the resist film.

[Conventional technology]

A monitor element is formed on the same substrate separately from the main element and measures its electrical characteristics independently in order to check the quality of the main element making up the semiconductor device during the wafer process. , formed to be the same as the main body element to be confirmed.

When forming the main body element, self-alignment of the processing is utilized as much as possible, and the resist film used as a mask for substrate processing is not affected even if it is slightly misaligned due to alignment errors during photolithography exposure. In order to avoid this, in many cases, the window (resist removal area) forming the pattern is made slightly larger than a predetermined size to allow for alignment.

Therefore, the same is applied to the formation of the monitor element.
An example of this is shown in the plan view and side sectional view of FIG. 3(a).

In FIG. 3, this monitor element is an FET, l is a substrate, 2 is a field insulating film, 3 is a gate electrode,
4 is a source/drain region, 5 is a resist film, and 6 is a window of the resist film 5.

The source/drain regions 4 are formed by ion implantation after providing the resist film 5, but the field insulating film 2
The window 6 should be defined in a self-aligned manner by the gate electrode 3 and the gate electrode 3, and a positioning margin α is provided for the window 6. The alignment margin α is made to match the corresponding alignment margin of the main body element to be checked.

Therefore, this monitor element is formed identically to the main body element to be checked, and the quality of the main body element can be checked. The same is true when the resist film 5 is misaligned beyond the margin α, the source/drain region 4 is sandwiched, the channel width becomes smaller than a predetermined value, and the characteristics change.

From this characteristic change, it is possible to detect the amount of positional deviation of the resist film 5 that exceeds the margin α.

[Problem to be solved by the invention]

However, such a monitor element cannot detect the positional deviation of the resist film 5 when the positional deviation of the resist film 5 is smaller than the margin α.

This means that 611 K? If there is a main body element in which the tolerance for positional deviation of the resist film 5 serving as a mask for ion implantation is smaller than the margin α, in addition to the main body element to be used as a mask for ion implantation, even if the latter main body element becomes defective, the defect cannot be recognized. This causes the problem of proceeding with the wafer process without any processing.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for detecting a positional shift of a resist film used as a mask for ion implantation of a main body element constituting a semiconductor device in a method of manufacturing a semiconductor device.

[Means for Solving the Problems] The above object includes a step of defining the ion implantation region of the monitor element with a film on the substrate on which the main body element is formed, and a process that is used as a mask for the ion implantation of the main body element. A monitor element is formed by forming a window in a resist film that should match the ion implantation area of the monitor element and performing the ion implantation, and then measuring the electrical characteristics of the monitor element. This is achieved by the first method of the present invention for detecting the positional shift of the resist film, and further includes a step of defining an ion implantation region of the monitor element with a film on the substrate on which the main body element is formed; A step of implanting ions of the one conductivity type by providing a window that exposes the entire ion implantation region of the monitor element in a first resist film used as a mask for ion implantation of one conductivity type of the element; forming windows whose edges should match each other on the outside of the ion implantation region of the monitor element in a second resist film used as a mask for ion implantation, and performing the opposite conductivity type ion implantation; This is achieved by the second method of the present invention, in which the positional deviation of the second resist film is detected by forming the second resist film and then measuring the electrical characteristics of the monitor element.

[Function] In the first method, the ion implantation region is masked by the positional shift of the resist film, and the diffusion region formed by ion implantation is narrowed by that amount. By using a monitor element whose characteristics reflect the sandwiching of the diffusion regions, it is possible to detect the positional shift of the resist film.

In addition, in the second method, a diffusion region of one conductivity type is formed in the ion implantation region by ion implantation of one conductivity type regardless of the positional deviation of the second resist film, and a diffusion region of the second conductivity type is formed in the second resist film by ion implantation of opposite conductivity type. Since the width is narrowed by the amount of deviation, by using a monitor element similar to that in the first method, only the positional deviation of the second resist film can be detected.

(Example) The plan view and side sectional view of FIG. This will be explained using the plan view and side sectional view of Figures (a) to (C).The same reference numerals indicate the same objects throughout the figures.

In FIG. 1, the monitor element of this first embodiment is a FET similar to that in FIG. 3, and 6a is a window corresponding to the window 6 in FIG.

The window 6a is arranged such that the alignment margin α mentioned above is set to O, and the edge of the window 6a matches the edge of the field insulating film 2 when the positional deviation of the resist film 5 is O, and this state is shown by the broken line. It will be done. The solid line indicates a state where the positional deviation is β.

When the positional deviation of the resist film 5 is β, the ion implantation region defined by the field insulating film 2 and the gate electrode 3 (the film on the substrate mentioned above) is β due to the bite of the resist film 5. The source/drain regions 4 formed by ion implantation are masked by B as shown by the solid line.
It will be narrowed down by that amount. The broken line indicates when the positional deviation is O.

Therefore, in this FET, when the positional shift of the resist film 50 is β, the channel width becomes smaller by β, and the characteristics change accordingly. Therefore, the positional shift of the resist film 5 can be detected from this characteristic change.

Next, in FIG. 2, in this second embodiment, when the main body element is implanted with both one conductivity type ion implantation and opposite conductivity type ion implantation, such as CMO3, either one of the masks is used. The monitor element is suitable for detecting the positional shift of the resist film in the first embodiment, and the monitor element is an FE sensor as in the first embodiment.
It is T.

Then, the plan view (a) shows the state after both ion implantations, the side sectional view (b) shows the state after the first conductivity type ion implantation, and the side sectional view (b) shows the state after the opposite conductivity type ion implantation, which is performed later. This shows the state where the type ion implantation has been completed, where the resist film 5 is a mask for one conductivity type ion implantation, 6b is a window corresponding to the previous window 6, 7 is a resist film used as a mask for reverse conductivity type ion implantation, and 8b is a resist film. This is a window provided in the film 7, and the resist film 7 is the object of positional deviation detection.

The window 6b has a large alignment margin α so that the ion implantation region defined by the field insulating film 2 and the gate electrode 3 is not masked by the positional shift of the resist film 5.

Therefore, at the end of one conductivity type ion implantation, (b)
As shown in FIG. 3, source/drain regions 4 of one conductivity type are formed following the ion implantation region.

The window 8b is provided outside the ion implantation region so that its edge coincides with the edge of the field insulating film 2 when the positional deviation of the resist film 7 is O, and this state is shown by a broken line. The solid line indicates a state where the positional deviation is β. Needless to say, the resist film 7 is provided after the resist film 5 is removed.

Then, when the positional deviation of the resist film 7 is β, the opposite conductivity type ions are implanted with the window 8b digging into the previously formed source/drain region 4 by β, so the ion implantation is performed in the dug-in area. is changed to the opposite conductivity type region 4a, and the one conductivity type source/drain region 4 is narrowed by β. When the positional deviation of the resist film 7 is 0, no such pinching occurs.

Therefore, in this FET, when the positional deviation of the resist film 7 is β, the channel width becomes smaller by β, and the characteristics change accordingly. Therefore, the positional shift of the resist film 7 can be detected from this characteristic change.

In this second embodiment, the order of both ion implantations is described as one conductivity type ion implantation and opposite conductivity type ion implantation, but even if the order is reversed, exactly the same result can be obtained.

In the above embodiment, the direction in which positional deviation can be detected is FET.
Therefore, if detection in both orthogonal directions is required, use two FETs and connect them to each other at 90°.
It is sufficient if the arrangement is shifted by 0 degrees. Further, by adding one FET and making its source/drain region 4 not narrowed by the resist film 5 or 7 and using it as a characteristic standard, the above-mentioned characteristic change can be made more clear. I can do it.

In the embodiment, a FET is used as a monitor element used for detecting positional deviation, but the monitor element is not limited to an FET, as long as the sandwiching of the diffusion region changes the characteristics.

[Effects of the Invention] As explained above, according to the configuration of the present invention, in a method of manufacturing a semiconductor device, the positional shift of a resist film used as a mask for ion implantation of a main body element constituting a semiconductor device is detected by a monitor element. By providing a detection method, it is possible to prevent the problem of proceeding with the wafer process without recognizing the defect when the main body element becomes defective due to the positional deviation.

[Brief explanation of drawings]

1(a) and 1(b) are a plan view and a side sectional view explaining the first embodiment, FIGS. 2(a) to (C) are a plan view and side sectional view explaining the second embodiment, 3(a) and 3(b) are a plan view and a side sectional view of an example of a conventional monitor element. In the figure, 1 is a substrate, 2 is a field insulating film, 3 is a gate electrode, 4 is a source/drain region, 4a is a region of opposite conductivity type, 5.7 is a resist film, 6.6a, 6b, and 8b are windows, α is the alignment margin, β is the positional deviation, and is.

Claims (1)

[Claims] 1) A step of defining the ion implantation region of the monitor element with a film on the substrate on which the main body element is formed, and adding the above to the resist film used as a mask for the ion implantation of the main body element. A monitor element is formed by providing a window that should match the ion implantation region of the monitor element and performing the ion implantation, and then measuring the electrical characteristics of the monitor element and determining the position of the resist film. A method of manufacturing a semiconductor device, the method comprising the step of detecting a deviation. 2) Defining the ion implantation region of the monitor element with a film on the substrate for the substrate forming the main body element, and applying the monitor element to the first resist film used as a mask for ion implantation of one conductivity type of the main body element. A step of implanting ions of one conductivity type by providing a window that exposes the entire ion implantation region of the element, and implanting ions of the monitor element into a second resist film used as a mask for ion implantation of the opposite conductivity type of the main element. A monitor element is formed by providing windows whose edges should match each other on the outside of the area and implanting ions of opposite conductivity type, and then measuring the electrical characteristics of the monitor element. 1. A method for manufacturing a semiconductor device, comprising the step of detecting a positional shift between two resist films.