JPH06252031A - Aligner and exposure method - Google Patents

Abstract

PURPOSE:To provide an aligner which is capacble of embodying exposure having a high resolution by making the best use of its exposure efficiency based on a phase shift technology and an exposure method thereof. CONSTITUTION:A first exposure mask M1 which has an exposure main pattern 1 and auxiliary patterns 2 to 5 and a second exposure mask M2 having an exposure pattern 7 larger than the exposure main pattern 1 of the first exposure mask M1 are used for exposure one after another where the phases of transmission light of the patterns are varied with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus and an exposure method. INDUSTRIAL APPLICABILITY The exposure apparatus and the exposure method of the present invention can be used as various pattern forming techniques, for example, an exposure technique for forming various patterns typified by a resist pattern in a semiconductor device manufacturing process. .

[0002]

2. Description of the Related Art A pattern forming device using a photomask, such as a semiconductor device, tends to have finer processing dimensions year by year. Against this background, various techniques have been proposed to further improve the resolution of the photolithography technique for obtaining a miniaturized semiconductor device. For example, one of them is a phase shift technique. The phase shift technique imparts a phase difference to the light passing through the mask, thereby improving the light intensity profile.

Phase shift masks have various configurations.
The phase of light is shifted between adjacent light transmitting parts (ideally 18
The phase shift mask for 0 ° inversion is called a spatial frequency modulation type (or Levenson type). Other,
There are various types of phase shift masks such as edge enhancement type and light shielding effect enhancement type. Among them, those having a shape without a light shielding portion (called chromeless type etc. However, in all of them, a phase shift unit for shifting the phase is provided in at least a part of the portion that transmits the exposure light.

[0004]

However, the technique using the phase shift mask has the following problems.

That is, the phase shift technique utilizes the effect of canceling the light intensities of the two by giving a phase difference to the light for exposing the adjacent patterns.
In the case of forming an isolated line or a contact hole, since there is no proximity light, the phase shift technique cannot be realized as it is.

Therefore, as shown in FIG. 14, a light transmitting portion (phase shift amount 0 °) for transmitting the exposure light without phase shifting is provided as the main pattern 1 corresponding to the pattern to be formed. , A technique has been proposed in which a phase shift portion (for example, a phase shift amount of 180 °) for shifting the exposure light is formed as auxiliary patterns 2 to 5 close to the light transmission portion which is the main pattern 1 (by Terazawa et al. Report, in the autumn of 1988, Proceedings of the 49th Annual Meeting of the Japan Society of Applied Physics 2 497 page 4a-K-7).

As described above, in forming a contact hole or the like by the phase shift technique using the auxiliary pattern method, the main pattern 1 to be resolved as a contact or the like, and the auxiliary patterns 2 to 5 surrounding the contact hole or the like. Composed of. According to this technique, as shown in FIG. 15, the light from the main pattern 1 and the light of the opposite phase from the auxiliary patterns 2 to 5 cancel each other (see “amplitude” in FIG. 15).
The contrast enhancement at the contact hole edge is realized (see "light intensity" in FIG. 15).

Therefore, in order to increase the contrast at the edge of the contact hole, it is desirable to increase the light intensity of the auxiliary patterns 2 to 5 so as to approach the light intensity of the main pattern 1. When 5 is increased, the contrast of the main pattern 1 is enhanced, but as shown in FIG.
The auxiliary patterns 2 to 5 themselves will be resolved, and will be different from the desired pattern. Therefore, the light intensity of the auxiliary patterns is made small (the width of the auxiliary patterns is narrow) so that the auxiliary patterns 2 to 5 are not exposed to the resist.
It must be on the order of 4, limiting the effectiveness of the phase shift technique.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and for an exposure using a phase shift technique, an exposure apparatus and an exposure method capable of realizing the exposure of high resolution by fully utilizing the effect. Is to provide.

[0010]

According to a first aspect of the present invention, there is provided a first exposure mask having an exposure main pattern and an auxiliary pattern, which are formed in a structure in which the phases of transmitted light are different from each other, and An exposure apparatus, comprising: a second exposure mask having an exposure pattern larger than the main exposure pattern of the first exposure mask, thereby achieving the above object.

According to a second aspect of the present invention, there is provided a first mask having a phase shift portion for making the phase of transmitted light different to transmit the exposure light, and transmitting the exposure light without making the phase of the transmitted light different. An exposure method is characterized in that exposure is performed by sequentially using a second mask for performing the exposure, thereby achieving the above object.

According to a third aspect of the present invention, there is provided a first exposure mask having an exposure main pattern and an auxiliary pattern formed in a structure in which the phases of transmitted light are different from each other, and the first exposure mask.
Second exposure mask having an exposure pattern larger than the exposure main pattern of the exposure mask of 1., the first resist on the workpiece is exposed by the first exposure mask, and the second resist is developed. Forming a resist on the material to be processed, exposing the second resist by the second exposure mask,
An exposure method including a developing step, which achieves the above object.

According to a fourth aspect of the present invention, there is provided a first exposure mask having an exposure main pattern and an auxiliary pattern, which are formed so as to make the phases of transmitted light different from each other, and the first exposure mask.
Second exposure mask having an exposure pattern larger than the main exposure pattern of the exposure mask of 1., the first resist on the workpiece is exposed by the second exposure mask, and after development, the second Forming a resist on the material to be processed, exposing the second resist by the first exposure mask,
An exposure method including a developing step, which achieves the above object.

According to a fifth aspect of the present invention, there is provided a first exposure mask having an exposure main pattern and an auxiliary pattern, which are formed so as to make the phases of transmitted light different from each other, and the first exposure mask.
A second exposure mask having an exposure pattern larger than the main exposure pattern of the exposure mask of 1., an inorganic material is formed on the work material, and then a first resist is formed on the work material. Exposing the first resist on the material to be processed by the first exposure mask, developing the second resist on the material to be processed, and then developing the second resist on the second exposure mask. An exposure method comprising the steps of exposing and developing by means of the above, and thereby achieving the above object.

According to a sixth aspect of the present invention, there is provided a first exposure mask having an exposure main pattern and an auxiliary pattern, which are formed in a structure in which the phases of transmitted light are different from each other, and the first exposure mask.
A second exposure mask having an exposure pattern larger than the main exposure pattern of the exposure mask of 1., an inorganic material is formed on the work material, and then a first resist is formed on the work material. Exposing the first resist on the material to be processed by the second exposure mask and developing the resist to form a second resist on the material to be processed, and then forming the second resist on the first exposure mask. An exposure method comprising the steps of exposing and developing by means of the above, and thereby achieving the above object.

[0016]

[Operation] According to the present invention, an exposure mask having a phase shift portion is used in combination with an ordinary exposure mask, so that the resolution of the main pattern can be obtained with sufficient phase shift effect and high resolution. be able to. This is because pattern exposure can be realized with the highest resolution by sequentially performing exposure using the first and second masks (the order of use is appropriately adopted depending on the resist) using the first and second resists.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. However, as a matter of course, the present invention is not limited to the following examples.

Example 1 In this example, the present invention is used for forming a fine contact hole in an integrated semiconductor device.

The phase shift mask of this embodiment is shown in FIG. As shown, in this embodiment, two masks M1 and M2 are used.
Is used. That is, in this embodiment, the first exposure mask M1 having the main exposure pattern 1 and the auxiliary patterns 2 to 5 formed in a configuration in which the phases of transmitted light are different from each other, and the exposure of the first exposure mask M1. Using both masks, a second exposure mask M2 having an exposure pattern 7 larger than the main pattern 1 for
Exposure is performed by the exposure device including M2.

Further, in the present embodiment, the first mask M1 provided with the phase shift portions 2 to 5 which make the phase of the transmitted light different and transmit the exposure light, and the exposure light without making the phase of the transmitted light different. The exposure is performed by sequentially using the second mask M2 that transmits the light.

Specifically, the two masks M1 and M2 used in this embodiment have the following structure.

In the first mask M1, the main pattern 1 is a prism having a side of 0.25 μm (which is referred to as a dimension on a wafer to be exposed).
The same applies hereinafter), the auxiliary patterns 2 to 5 are 0.25 μm (having a shifter material), and the distance between the main pattern 1 and the auxiliary patterns 2 to 5 is 0.16 μm.

The second mask M2 has a pattern 7 obtained by enlarging the main pattern 1 of the mask M1 by 0.08 μm.

The product of the mask M1 and the mask M2 becomes a desired pattern. Therefore, patterning is performed with the minimum pattern. In this embodiment, KrF excimer laser exposure is performed to form a fine contact hole of 0.25 μm.

2 to 5 show the exposure process in this embodiment. In the present embodiment, as shown in FIGS. 2 to 5, a first exposure mask M1 having an exposure main pattern 1 and auxiliary patterns 2 to 5 formed in a configuration in which the phases of transmitted light are different from each other, The first exposure mask M1
A second exposure mask M2 having an exposure pattern 7 larger than the main exposure pattern 1 of
The first resist 9 on (specifically, the interlayer film on the wafer) is exposed by the first exposure mask M1 and developed to form the structure shown in FIG. 2, and then the second resist 14 is used as a workpiece. 10 is formed (FIG. 3), the second resist 14 is exposed by the second exposure mask M2 and developed (FIG. 4).

More specifically, in this embodiment, resist patterning by desired exposure and processing of the material to be processed (etching in this case) were performed in the following steps (1) to (3).

Interlayer film (SiO ₂ ) which is the workpiece 10
The first resist 9, which is a positive resist, has a film thickness of 1 μm.
Apply to m. The mask M1 is used, and after exposure by a stepper using a KrF excimer laser as a light source, development and baking are performed. As shown in FIG. 2, the main pattern 11 is 0.
25 μmφ, and the auxiliary patterns 12 and 13 are slightly larger than the main pattern.

A second resist 14 (positive resist) is applied to a film thickness of 1 μm (or less) (FIG. 3).

The second mask M2 is aligned with the pattern of the first mask M1 (alignment accuracy 0.08 μm), exposed, and then developed and baked. Second resist 14
The opening 15 (0.41 μmφ) is formed. Due to the alignment error, the opening portion 15 is replaced by the opening portions 12, 1 of the resist 1.
It does not overlap 3.

First resist 9 and second resist 1
Using the mask 4 as a mask, the interlayer film which is the workpiece 10 is etched to form the contact hole 16.

As described above, a highly accurate contact hole corresponding to the fine main pattern 11 (main pattern 1 of the mask M1) was formed. This is because the auxiliary patterns 2 to 5 of the first mask M1 are formed with the same size as that of the main pattern 1, the light intensities that are offset by phase inversion are equalized, and the contrast is extremely large. Moreover, by using the second mask M2 together, the second resist 14
As a result, the resist openings 12 and 13 of the first resist 9 formed by the auxiliary patterns 2 to 5 are masked by
It does not affect 0.

As the first and second resists, it is preferable to use different resists and different solvents. It is preferable that they are not compatible, and it is possible to perform patterning development completely independently. In this embodiment, a PMMA-based resist developed with an organic solvent is used as the first resist 9, and the second resist 1 is used.
As No. 4, a novolac-based resist developed with an alkaline developer was used.

According to this embodiment, the resolution of contact hole formation was improved by using the exposure mask using the phase shift technique of the auxiliary pattern system, and the resolution similar to that of the Levenson system line and space was realized. This makes the LSI
If it is possible to improve the degree of integration of. In addition, this embodiment can use the same manufacturing apparatus and process as the conventional one except for the mask.

Example 2 In this example, in the step of Example 1, another inorganic material is deposited on the interlayer film which is the workpiece 10 before applying the first resist 9a (see FIG. 6). (For example, the interlayer film is S
For SiO ₂ , PolySi or SiN. 6 to 8
Then, PolySi is displayed as this material layer 17), and this material layer 17 is patterned using the first resist 9a (FIG. 6) patterned with the first mask M1 (FIG. 7). Second resist 14a (patterned by the second mask M2. The exposed portion is shown in FIG.
8) by using the composite structure of FIG.
14c, contact holes are formed in the interlayer film, which is the workpiece 10.

Third Embodiment This embodiment is a modification of the first embodiment. In Example 1, first, the desired fine pattern was transferred to the resist by the main pattern 1 using the first mask M1, but in the present example, the second mask 2 was used first to form the desired resist 9 on the first resist 9. The pattern 7 was transferred, then the second resist 14 was applied and formed, and the main pattern 1 was transferred using the first mask M1. As a result, this embodiment can also form a contact hole similar to that of the first embodiment.

Fourth Embodiment This embodiment is a modification of the second embodiment. In Example 2, after forming the inorganic material layer 17, first, a desired fine pattern was transferred to the first resist 9a by the main pattern 1 using the first mask M1, but in the present example, the second pattern is first formed. Mask 2
Is used to transfer the pattern 7 to the first resist 9a,
After that, a second resist 14a was applied and formed, and the main pattern 1 was transferred here using the first mask M1. Also in this embodiment, as a result, a contact hole similar to that of the second embodiment can be formed.

Example 5 In each of the above examples, a positive resist was used to form a concave pattern on a workpiece, but in the present example, a negative resist was used to form a convex pattern (island pattern).

Please refer to FIG. 9 to FIG. In the present embodiment, a negative resist pattern 9B is formed on the material to be processed 10 (SiO ₂ etc.) by the second mask (FIG. 9), and the second resist 14B is formed by coating (FIG. 10). A fine pattern 14B is formed by a mask, and thereby the lower pattern 9B is processed to form a fine pattern 9B '. At the same time, or after the pattern 9B' is formed, the workpiece 10 is processed to form a convex pattern. A pattern of islands.

Embodiment 6 In each of the embodiments described above, a mask of the type shown in FIG. 14 in which the auxiliary patterns 2 to 5 are formed around the main pattern 1 is used as the first mask. Then, in FIG.
As shown in FIG. 5, the same pattern formation as in each of the above-described examples was performed using a mask having a structure in which the phase shift portion 20 completely surrounds the main pattern 1 as an auxiliary pattern. According to this embodiment, the same effect as each of the above-mentioned examples was obtained.

[0040]

As described above, according to the exposure apparatus and the exposure method of the present invention, regarding the exposure using the phase shift technique,
There is an effect that exposure with high resolution can be realized by fully utilizing the effect.

[Brief description of drawings]

FIG. 1 is a plan view showing a mask according to a first embodiment.

FIG. 2 is a diagram showing an exposure process of Example 1 (1).

FIG. 3 is a diagram showing an exposure process of Example 1 (2).

FIG. 4 is a diagram showing an exposure process of Example 1 (3).

FIG. 5 is a diagram showing an exposure process of Example 1 (4).

FIG. 6 is a diagram showing an exposure process of Example 2 (1).

FIG. 7 is a diagram showing an exposure process of Example 2 (2).

FIG. 8 is a diagram showing an exposure process of Example 2 (3).

FIG. 9 is a diagram showing an exposure process of Example 5 (1).

FIG. 10 is a diagram showing an exposure process of Example 5 (2).

FIG. 11 is a diagram showing an exposure process of Example 5 (3).

FIG. 12 is a diagram showing an exposure process of Example 5 (4).

FIG. 13 is a diagram showing a modified mask.

FIG. 14 is a diagram showing a conventional technique.

FIG. 15 is a diagram showing a conventional technique.

FIG. 16 is a diagram showing a problem of the conventional technique.

[Explanation of symbols]

 M1 1st mask M2 2nd mask 1 Main pattern 2-5 Auxiliary pattern 7 2nd mask pattern 9, 9a, 9B 1st resist 10 Work material 14, 14a, 14B 2nd resist

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location 7352-4M H01L 21/30 311 L 7352-4M 361 S

Claims (6)

[Claims] 1. A first exposure mask having an exposure main pattern and an auxiliary pattern formed in a structure in which the phases of transmitted light are different from each other, and an exposure larger than the exposure main pattern of the first exposure mask. And a second exposure mask having a pattern. 2. A first mask provided with a phase shift section for transmitting the exposure light by changing the phase of the transmitted light and a second mask for transmitting the exposure light without changing the phase of the transmitted light. An exposure method comprising performing exposure using the method. 3. A first exposure mask having an exposure main pattern and an auxiliary pattern formed in a structure in which the phases of transmitted light are different from each other, and an exposure larger than the exposure main pattern of the first exposure mask. A second exposure mask having a pattern is used to expose a first resist on the workpiece by the first exposure mask, and after development, a second resist is formed on the workpiece, An exposure method comprising the step of exposing the second resist with the second exposure mask and developing the resist. 4. A first exposure mask having an exposure main pattern and an auxiliary pattern formed in a structure in which the phases of transmitted light are different from each other, and an exposure larger than the main exposure pattern of the first exposure mask. A second exposure mask having a pattern is used to expose a first resist on the workpiece by the second exposure mask, and after development, a second resist is formed on the workpiece, An exposure method comprising the step of exposing the second resist with the first exposure mask and developing it. 5. A first exposure mask having an exposure main pattern and an auxiliary pattern formed in a structure in which the phases of transmitted light are different from each other, and an exposure larger than the exposure main pattern of the first exposure mask. A second exposure mask having a pattern is used to form an inorganic material on the material to be processed, and then a first resist is formed on the material to be processed, and the first resist on the material to be processed is described above. A step of forming a second resist on the material to be processed after exposure by the first exposure mask and development, exposing the second resist by the second exposure mask, and developing. Exposure method. 6. A first exposure mask having an exposure main pattern and an auxiliary pattern formed in a structure in which the phases of transmitted light are different from each other, and an exposure larger than the exposure main pattern of the first exposure mask. A second exposure mask having a pattern is used to form an inorganic material on the material to be processed, and then a first resist is formed on the material to be processed, and the first resist on the material to be processed is described above. A step of forming a second resist on the material to be processed after exposure by the second exposure mask and development, exposing the second resist by the first exposure mask, and developing. Exposure method.