JPH0429143A - Manufacture of phase shift mask - Google Patents

Abstract

PURPOSE:To obtain the phase shift mask without damaging its substrate by removing the side part of a light shield material film, forming a phase shift material film, and then removing a resist pattern. CONSTITUTION:The light shield material film 101 is formed on the substrate 1, and the resist pattern 2 is formed on the light shield material, which is patterned to form a light shield part 10; and the patterning is so carried out at this time that the light shield material film 101 is removed even below the side part 21 of the resist pattern 2. Then the phase shift material film 31 is formed and then the resist pattern 2 is removed to obtain the phase shift mask which has a light transmission part 12 formed between the light shield part 10 and phase shift part 11. Consequently, the phase shift mask can be manufac tured without dry etching, so the phase shift mask can be obtained without damaging the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] Each invention of the present application relates to a method of manufacturing a phase shift mask. Phase shift masks can be used in various pattern forming techniques, and can be used, for example, as masks for forming resist patterns in semiconductor device manufacturing processes. This can be used when manufacturing shift masks.

[Summary of the Invention] The invention of claim 1 of the present application provides that when a resist pattern is formed on the rise of a light-shielding material formed on a substrate and the light-shielding material film is patterned to form a light-shielding part, the side of the light-shielding material film is By forming a phase shift material film, and then removing the resist pattern,
A structure is adopted in which a light transmitting part is formed in a portion corresponding to the removed side part between the light shielding part and the phase shift part, so that a phase shift mask that does not cause damage to the substrate due to etching can be obtained. This is what I did.

The invention of claim 2 of the present application provides that when a resist pattern is formed on a phase shift material film formed on a substrate and the phase shift material film is buttered to form a phase shift portion, the side of the phase shift material film is Then, by forming a light-shielding material film and then removing the resist pattern, a light-transmitting part is formed in the portion corresponding to the removed side part between the light-shielding part and the phase shift part. With this structure, it is possible to obtain a phase shift mask which can be constructed so that damage to the substrate does not occur due to etching, and which also facilitates the formation of phase shift portions.

[Conventional technology]

Phase shift masks can be used in various pattern forming techniques, for example in semiconductor device manufacturing processes.
It can be used as a mask when forming a resist pattern.

Phase shift masks apply so-called phase shift technology that imparts a phase difference to the light passing through the mask, thereby improving the light intensity profile, and can further improve the resolution in photolithography technology. , has been attracting particular attention in recent years as a mask technology for producing semiconductor devices whose processing dimensions tend to become smaller year by year.

For phase shift technology, see Japanese Patent Application Laid-Open No. 58-173744.
Publications, MARCD, LEVENSON and others “Imp
roving Re5solutionin Photo
Lithography with a Phase-
5hifting Mask”IEEE TRANS
ACTIONS ON ELECTRON DE
VICES, VOL.

HD-29No, 12. DECEMBER19B2.
P1828-1836, also MARCD, LEVEN
SON and others “The Phase-5lifting M
ask II: Imaging Simulation
ns and Submicrometer Re5i
stExposures” magazine Vow, ED-31,
No, 6. It is described in JtlNE 1984P753-763.

The conventionally known phase shift method will be explained using FIG. 7 as follows.

For example, when forming a line-and-space pattern, a normal conventional mask uses a light-shielding material such as Cr (chromium) on a transparent substrate 1 such as a quartz substrate, as shown in FIG. 7(a). The light shielding part 10 is formed using a material, and a repeating pattern of, for example, lines and spaces is formed thereby to serve as an exposure mask. The intensity distribution of the light transmitted through this exposure mask is shown in FIG. 7(a) with the symbol A1.
As shown in , ideally the light is zero at the light shielding part 10 and is transmitted at other parts (transmissive parts 12a, 12b).

Considering one transmitting part 12a, the transmitted light given to the exposed material has a light intensity distribution with hill-like peaks at both sides, as shown by A2 in FIG. 7(a), due to light diffraction, etc. become. The transmitted light A2' toward the transmitting portion 12b is indicated by a dashed-dotted line. Each transparent part 12a.

When the lights from 12b are combined, the light intensity distribution loses its sharpness as shown in A3, and the image becomes blurred due to light diffraction, making it impossible to achieve sharp exposure. On the other hand, the light transmitting portions 12a and 12b of the repeating pattern
If a phase shift section (referred to as a "shift") 11 is provided on every other shift as shown in FIG.
A sharp image is transferred, improving resolution and focus latitude.

That is, as shown in FIG. 7(b), when the phase shift portion 11 is formed in one of the transmission portions 12a, the phase shift portion 11 is, for example, 180
If a phase shift of .degree. is given, the light passing through the phase shift section 11 is inverted as shown by the symbol B1. Since the light from the adjacent transmission section 12b does not pass through the phase shift section 11, such inversion does not occur. The light applied to the exposed material is inverted and cancels each other out at the bottom of the light intensity distribution at the position indicated by B2 in the figure, resulting in the distribution of light applied to the exposed material as shown in Figure 7(b). As shown in B3, it has a sharp ideal shape.

In the above case, in order to most ensure this effect, it is most advantageous to invert the phase by 180 degrees. establish.

When forming a pattern by exposure, the one that performs reduced projection is sometimes called a reticle, and the one that projects one-to-one is called a mask, or the one that corresponds to the original is called a reticle, and the one that reproduces it is called a mask. However, in the present invention, masks and reticles in various meanings are collectively referred to as a mask.

[Problem that the invention seeks to solve]

As a structure of the phase shift mask as described above, there is one in which a phase shift part is formed adjacent to a peripheral part of a light shielding part made of a light shielding material such as chromium.

An example of such a structure is shown in FIG. 5(a). The example in FIG. 5(a) shows a light shielding part 1 formed on a substrate 1.
A phase shift material film 11' is formed to cover the phase shift material film 11', and a side end portion of the phase shift material film 11' that does not overlap with the light shielding part 10 is used as a phase shift part 11. The structure is such that a light transmitting part 12 exists between such phase shift parts 11.

FIG. 5(b) shows another example of the above structure. In the example shown in FIG. 5(b), a light shielding part 10 is formed on the phase shift material film 11' formed on the substrate 1 so as not to completely cover it, and the phase shift material film 11'
The side end portion of the light shielding portion 10 that is not covered with the light shielding portion 10 is used as a phase shift portion 11 . In this example as well, the light transmission section 12 exists between the phase shift sections 11.

However, all of these conventional structures require some form of etching of the phase shift material on the substrate 1.

For example, FIG. 6 shows a case where a structure as shown in FIG. 5(b) is to be obtained by etching a phase shift material (for example, 5i(h)) on a substrate 1 such as glass using a resist 2 or the like as a mask. At this time, if dry etching such as RIE is performed, it is inevitable to damage the underlying substrate 1. In Fig. 6, arrow A indicates the etching situation. This is schematically shown, and the damage to the substrate 1 caused by this is also schematically represented by a waveform indicated by B.

The present invention attempts to solve the above problems.

That is, an object of the invention of claim 1 of the present application is to provide a method for manufacturing a phase shift mask that can obtain a phase shift portion without damaging the substrate.

The invention of claim 2 of the present application is intended to provide a method for manufacturing a phase shift mask that allows the phase shift portion to be formed more easily in accordance with the object.

[Means for solving problems]

Each invention of the present application achieves the above object with the following configuration.

That is, the invention of claim 1 of the present application is a method for manufacturing a phase shift mask comprising a light shielding part, a light transmitting part, and a phase shift part on a substrate, the method comprising forming a light shielding material film on the substrate. ,
A resist pattern is formed on the light-shielding material film, and the light-shielding material film is patterned to form a light-shielding part, and at the same time, the patterning is performed so that the light-shielding material film is also removed under the side portions of the resist pattern. This is a method for manufacturing a phase shift mask in which a phase shift mask is obtained in which a light transmitting part is formed between a light shielding part and a phase shift part by forming a phase shift material film and then removing a resist pattern. .

The invention of claim 2 of the present application is a method for manufacturing a phase shift mask comprising a light shielding part, a light transmitting part, and a phase shift part on a substrate, the method comprising: forming a phase shift material film on the substrate;
A resist pattern is formed on the phase shift material film, and the phase shift material film is patterned to form a phase shift portion, and at the same time, the phase shift material film is also removed under the side portions of the resist pattern. A phase shift mask in which a light transmitting part is formed between a light shielding part and a phase shift part is obtained by patterning the mask so as to form a light shielding material film, and then removing the resist pattern. This is the manufacturing method.

[For production]

According to each invention of the present application, a phase shift mask can be manufactured without using dry etching to form a phase shift portion. Therefore, a phase shift mask can be obtained without damaging the substrate.

〔Example〕

Examples of each invention of the present application will be described below.

However, it goes without saying that each invention is not limited to each embodiment described below.

Example 1 This example embodies the invention of claim 1 of the present application, and is particularly suitable for manufacturing phase shift masks used in manufacturing miniaturized and integrated semiconductor devices. It uses an invention.

In this embodiment, chromium or the like is formed on the entire surface of a substrate 1 such as a glass substrate to form a light-shielding material film 10', thereby obtaining the structure shown in FIG. 1(a).

Next, a resist pattern 2 is formed on the light shielding material film 10'. A resist opening in resist pattern 2 is indicated by reference numeral 22. Using this resist pattern 2, the light shielding material film 1 is
0' is patterned to form a light shielding part 10. During this patterning, patterning is performed so that the light-shielding material film 10' is also removed under the side portions 21 of the resist pattern 2. Specifically, such patterning can be achieved by performing isotropic etching using the resist pattern 2 as a mask. As the isotropic etching means, for example, an etching liquid that etches the light-shielding material may be used, and wet etching may be performed using this to proceed with so-called side etching. When the light shielding material is chromium, etching can be carried out using a general-purpose chromium etching solution.

Through this step, the structure shown in FIG. 1(b) is obtained.

Side portion 21 of resist pattern 2 of light shielding material film 10'
The removed portion (side-etched portion) at the bottom is indicated by the reference numeral 10''.

Next, a phase shift material film 31 is formed using SiO□ or the like.

As a result, a phase shift material film 31 is formed on the substrate 1 directly below the opening 22 of the resist pattern 2, as shown in FIG. 1(C). The portion where the side portion of the light-shielding material film 10 described above is removed, that is, the portion indicated by reference numeral 10#, has the resist pattern 2 (particularly the side edge portion 21) thereon, so there is no phase shift here. No material film is formed. At this time, a film 32 made of phase shift material is also formed on the resist pattern 2. Phase shift material film 31
For the formation method, an appropriate method may be used depending on the material used, but in the case of Sing, for example, a sputtering method can be used. Other means for forming the film do not matter.

After that, when the resist pattern 2 is removed, as shown in FIG.
) structure is obtained. At this time, the film 32 made of the phase shift material on the resist pattern 2 is
This is called lift-off. As a result, the part corresponding to the part indicated by the reference numeral 10'' explained above remains in the form where the substrate 1 is exposed as it is, and the light transmitting part 12
becomes.

Thereby, a phase shift mask is obtained in which a light transmitting section 12 is formed between a light shielding section 10 and a phase shifting section 11, as clearly shown in FIG. The width Δ of the light transmitting portion 12 is determined by the portion where the side portion of the light shielding material film is removed (see FIGS. 1(b) and 1(c)).
This width Δ can be determined by controlling the removal process.

In this embodiment, it is not necessary to perform dry etching such as RIE for etching the phase shift film, thereby preventing damage to the substrate.

In the description of the above embodiment, it is assumed that the substrate 1 can be made of glass, but it may be made of any material as long as it is transparent to the exposure light used, and other materials such as quartz or glass containing various components as appropriate may be used. Can be used. Also, the light shielding part 1
In addition to chromium, chromium oxide, general high-melting point metals (W, Mo, Be, etc.), and their oxides, silicides, etc. can also be used for 0.

The material of the phase shift part 11 is also SiO, in addition to 5i (h).
Any material can be used, such as silicon nitride or various resists, as long as it has good exposure light transparency and can achieve the desired phase shift.

Example 2 This example embodies the invention of claim 2 of the present application, and is applied to the creation of a phase shift mask used in the same field as Example 1.

Refer to the third answer diagram.

In this embodiment, a phase shift material film 11' is formed on the substrate 1 as shown in FIG. 3(a).

Next, a resist pattern 2 is formed on the phase shift material film 11' to obtain the structure shown in FIG. 3(b).

Next, the phase shift material film 11' is patterned using the resist pattern 2 as a mask to form the phase shift portion 11. At this time, patterning is performed so that the phase shift material film is also removed under the side portions 21 of the resist pattern 2. This can be achieved by isotropic etching, wet etching, side etching, etc. based on the same concept as in Example-1. As a result, the structure shown in FIG. 3(C) is obtained.

Next, a light shielding material film 41 is formed. Here, 1. A light shielding material film 41 was obtained by sputtering heavy metal silicide, particularly molybdenum silicide. As a result, as shown in FIG. 3(d), a light-shielding material film 41 is formed in the portion not masked by the resist pattern 2, that is, a structure in which no film is formed between the phase shift portion 11 and the light-shielding material film 41. is obtained. This is the same as described with respect to FIG. 1(c).

Thereafter, by removing the resist pattern 2, the structure shown in FIG. 3(e) is obtained. In FIG. 3(d),
The light shielding material film 42 formed on the resist pattern 2 is
Lifted off.

As a result, a phase shift mask similar to that shown in FIG. 2 is obtained, in which a light transmitting section 12 is formed between the light shielding section 1O and the phase shift section 11.

According to this embodiment, isotropic etching is used instead of dry etching such as RIE to remove the phase shift material film 11', thereby preventing damage to the substrate 1. In addition, in Example 1, the phase shift material was formed through the opening 22 (see FIG. 1(c)) between the resist patterns 2, so if the opening 22 is narrow, the phase shift material may be formed by sputtering, etc. However, in this embodiment, the phase shift portion can be obtained without such concerns.

For example, as shown in FIG. 4, a light shielding part 10 is formed on the entire surface, a contact hole-shaped phase shift part 11 is provided so as to be surrounded by the light shielding part 10, and the phase shift part 11 is surrounded by the light shielding part 10. This is advantageous when a phase shift mask is formed by providing the light transmitting portion 12 in a surrounding structure.

Phase shift part 1 compatible with minute contact hole shapes
This is because it is easy to provide 1 in this embodiment.

In this embodiment, molybdenum silicide MoS i 2 was used as the material for forming the light shielding part 10, but as in the first embodiment, various materials may be used.

Further, as in Example-1, the material of the substrate 1 and the material of the phase shift section 11 may be arbitrarily used as long as the present configuration is applicable.

〔Effect of the invention〕

As described above, the manufacturing method according to the invention of claim 1 of the present application does not require the use of dry etching means for patterning the phase shift film, so it is possible to achieve a good phase shift effect without damaging the underlying substrate. A phase shift mask can be obtained that results in a phase shift mask.

Further, the manufacturing method according to the invention of claim 2 of the present application does not require the use of dry etching for patterning the phase shift film, and therefore can be configured so as not to damage the substrate. Therefore, it is advantageous when it is necessary to form a phase shift portion in a minute portion.

[Brief explanation of drawings]

FIGS. 1(a) to 1(d) are cross-sectional views showing the steps of Example 1 in the manufacturing process of a phase shift mask. FIG. 2 is a cross-sectional view of the phase shift mask obtained in Example-1. FIGS. 3(a) to 3(e) are cross-sectional views showing the steps of Example 2 in the manufacturing process of a phase shift mask. FIG. 4 is a plan view of an example of a phase shift mask to which Example-2 can be applied. Figures 5(a) and 5(b) are
FIG. 3 is a cross-sectional view showing a configuration example of a conventional phase shift mask. FIG. 6 is a diagram showing the problem. FIG. 7 is a diagram explaining the principle of a phase shift mask. DESCRIPTION OF SYMBOLS 1... Substrate, 11'... Phase shift material film, 11.
... Phase shift part, 12... Light transmitting part, 10... Light blocking part, 10'... Light blocking material film, 2... Resist pattern, 31... Phase soft material film, 41... Light-shielding material film.

Claims (1)

[Claims] 1. A method for manufacturing a phase shift mask comprising a light-shielding part, a light-transmitting part, and a phase-shifting part on a substrate, the method comprising: forming a light-shielding material film on the substrate; A resist pattern is formed on the film, and the light-shielding material film is patterned to form a light-shielding portion, and at the same time, the patterning is performed so that the light-shielding material film is also removed under the side portions of the resist pattern, and then A method for manufacturing a phase shift mask, comprising forming a phase shift material film and then removing a resist pattern to obtain a phase shift mask in which a light transmitting part is formed between a light shielding part and a phase shift part. 2. A method for manufacturing a phase shift mask comprising a light shielding part, a light transmitting part, and a phase shift part on a substrate, the method comprising forming a phase shift material film on the substrate, and depositing a resist on the phase shift material film. A pattern is formed and the phase shift material film is patterned to form a phase shift portion, and at the same time, patterning is performed so that the phase shift material film is also removed under the side portions of the resist pattern, and then light shielding is performed. A method for producing a phase shift mask, comprising forming a material film and then removing a resist pattern to obtain a phase shift mask in which a light transmitting part is formed between a light shielding part and a phase shift part.