JPH0274023A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To enable the proper exposure amount to be selected for assuring accurate patterning process by a method wherein fine patterns exceeding the resolving power limit formed on a part of a mask are transferred to a flat part on a wafer to produce a residual resist. CONSTITUTION:Within photolithographic process, fine patterns 9 exceeding the resolving power limit on a part of a mask are transferred to a flat part on a wafer to produce a residual resist 10. That is, the exposure amount can be decided by measuring the film thickness of the residual resist on the flat part on the wafer. The reference residual resist film subject to proper exposure can be decided by monitoring the residual resist film amount corresponding to the proper exposure to avoid any residual resist left on the lower stepped part 11 on the wafer so that the proper exposure amount may be judged by checking if the thickness of the residual resist film is above or below the reference of the residual resist film. Through these procedures, the residual resist film left on the lower stepped part can be avoided further enabling the exposure amount for measuring the proper resist dimension to be decided.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a semiconductor device using a very fine pattern in a lithography process.

2. Description of the Related Art In recent years, semiconductor device manufacturing methods have become more complex and longer (
Along with this, the steps on the silicon surface are becoming larger and larger. On the other hand, as patterns become increasingly finer and dimension tolerances become smaller, it is becoming extremely difficult to control the exposure amount in the photolithography process.

A conventional method for manufacturing a semiconductor device will be described below.

FIG. 5 shows a cross-sectional view of a conventional photolithography process. In Fig. 5, ■ is the light emitted from the mercury lamp of the exposure machine, and 2 is the quartz plate.

3 is a chromium pattern that blocks the light from 1; 64 is a patterned positive resist; 5 is a second layer of polycrystalline silicon; 6 is a first layer of polycrystalline silicon; 7 is an oxide film; 8 is a silicon substrate , 12 are the remaining resists.

In the conventional method, an appropriate exposure amount was determined by measuring the dimension e of a resist pattern formed on a flat portion.

That is, the method was to obtain the desired resist dimension e and to avoid leaving any resist residue 12 at the bottom of the step or in the recess.

Problems to be Solved by the Invention However, in the above conventional method, the resist dimension e
is the lateral component with respect to the silicon wafer, and the fifth
The remaining resist 12 in the figure is a component in the depth direction with respect to the silicon wafer, and the two do not necessarily correspond sufficiently, resulting in resist remaining at the bottom of the step, or conversely, excessive exposure. This has the disadvantage that the resist size becomes thinner than necessary.

The present invention solves the above-mentioned conventional problems, and aims to provide a semiconductor device manufacturing method that prevents resist from remaining at the bottom of the step and determines the exposure amount to obtain appropriate resist dimensions. .

Means for Solving the Problem In order to achieve this object, the method for manufacturing a semiconductor device of the present invention has a fine pattern exceeding the resolution limit in a part of the mask in the photolithography process, and the pattern is transferred to the wafer. It consists of a method of generating resist residue by transferring it to the upper flat area.

Effect: With this method, the exposure amount can be determined by measuring the thickness of the resist remaining on the flat portion of the wafer. That is, by monitoring the amount of resist remaining film that corresponds to the appropriate exposure amount that can prevent the resist from remaining on the lower part of the step on the wafer, a resist remaining film standard for the appropriate exposure amount can be determined. Depending on whether the resist remaining film is thicker or thinner than the standard, it can be determined whether the exposure amount is large or small.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross section of a wafer and a mask in a method of manufacturing a semiconductor device according to a first embodiment of the present invention.

In FIG. 1, 1 is light emitted from a mercury lamp of an exposure machine, 2 is a quartz plate, and 3 is a chrome pattern that blocks the light. 4 is a patterned positive resist, 5 is a second layer of polycrystalline silicon, 6 is a first layer of polycrystalline silicon, 7 is oxidation, 8 is a silicon substrate, 9 is a fine chromium pattern that exceeds the resolution limit, Reference numeral 10 indicates a portion where the yam chrome pattern 9 has been transferred, and the resist remains. Reference numeral 11 indicates the lower part of the step where resist residue is likely to occur.

In FIG. 1, a resist residue 10 is generated on the polycrystalline silicon 5 directly under the fine pattern 9 which exceeds the resolution limit, and the film thickness thereof is measured. Depending on the film thickness, it can be determined whether the exposure amount at that time is sufficient to prevent the formation of resist residue in the lower part 11 of the step shown in FIG. Next, the reason why the resist remaining 10 shown in FIG. 1 occurs will be briefly explained. FIG. 2 shows a model of light intensity when light is blocked by a mask. The left side shows the light intensity in a normal pattern. The right side shows the light intensity that passed through the pattern beyond the resolution limit. The light intensity is low, resulting in underexposure, resulting in resist residue.

As described above, according to this embodiment, by providing a pattern that exceeds the resolution limit in a part of the mask, a resist residue is generated in one flat area on the wafer, and by detecting the film thickness, it is possible to It is possible to determine the appropriate exposure amount that will not leave any resist behind.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows a cross section of a wafer and a mask having three types of pattern groups with different pattern densities and exceeding the resolution limit of the semiconductor device manufacturing method according to the second embodiment of the present invention.

This figure has the same configuration as Figure 1, but there are three types of mask patterns, and the difference from Figure 1 is that there is no resist remaining on the left side, and there is resist remaining on the center and right sides. ing. Further, FIG. 4 shows a drawing of a 5x reticle as an example of a mask pattern.

In this way, by arranging and transferring several groups of patterns with different pattern densities, a pattern that does not generate any resist residue appears. In that case, the denser the pattern, the more likely the resist will remain.

As described above, by exceeding the resolution limit and providing several pattern groups with different pattern densities, some parts of the pattern group will have resist remaining and some parts will not. The exposure amount can be determined by reading the position.

In the embodiment, the resist 4 is of a positive type, but the resist 4 may be of a negative type. However, in that case, the light blocking portion and the light transmitting portion of the mask are reversed.

Although a very deep step 11 is provided in the embodiment, it goes without saying that an appropriate exposure amount can be determined even when there is no step.

In the example, second layer polycrystalline silicon5. The first layer polycrystalline silicon 6 and the oxide film 7 are not necessarily necessarily the same, and are merely examples of the -process.

Effects of the Invention As described above, according to the present invention, a part of the mask has:
By transferring a fine pattern that exceeds the resolution limit to a flat area on the wafer and generating resist residue, it is possible to select the appropriate exposure amount and perform accurate patterning. Therefore, this technology can realize an excellent semiconductor device.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a wafer and a mask in a method for manufacturing a semiconductor device according to a first embodiment of the present invention, and FIG. 2 is a model diagram showing the light intensity of light that has passed through a pattern exceeding the resolution limit. FIG. 3 is a sectional view of a wafer and a mask in a method for manufacturing a semiconductor device according to a second embodiment of the present invention;
The figure is a pattern plan view of a 5x reticle, and FIG. 5 is a cross-sectional view of a wafer and mask in a conventional semiconductor device manufacturing method. ■...Light, 2...Quartz plate, 3...
...Chrome pattern, 4...Resist pattern, 5...2nd layer polycrystalline silicon, 6...
・First layer polycrystalline silicon, 7...Oxide film, 8.
... Silicon substrate, 9 ... Chrome pattern exceeding resolution limit, 10 ... Resist residue, 11 ... Bottom of step. Name of agent: Patent attorney Shigetaka Awano and 1 other person 1-Hikari? - Quartz treatment δ - - Silicon substrate i2 Figure 1 - Light 2 - Quartz plate 3 - Chrome pattern 1l - IiJ? , Kanegeshuichi Figure 1-19? -・Stone lost board S-Z layer 1000 crystal silicon 7---Acid L film 8 ゛Silicon substrate 9-゛Dissolved to the best of my ability-1, @er=7o muhagoon 10
-m-to the sound mouth mouth mouth mouth mouth lo lo lo lo mouth mouth lo lo lo lo mouth lo lo lo lo lo lo lo lo lo lo lo lo lo lo lo lo lo lo lo lo lo loロ 口ロ ロ ロ ロ ロロ ロ ロ ロ ロ ロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロロ］グａｂｗｉｙ−７（ｆ：！Ｌ九部）

Claims (1)

[Claims] A method for manufacturing a semiconductor device, characterized in that a part of the mask has a fine pattern that exceeds the resolution limit, and the mask pattern is transferred to a flat area on a wafer to generate a resist residue.