JPH06242594A - Mask for deformed illuminating exposure device - Google Patents

Abstract

PURPOSE:To provide a mask for the deformed illuminating exposure device capable of improving the resolution of isolated patterns. CONSTITUTION:Auxiliary patterns AS1, AS2 of line width sw1, sw2 are arranged by maintaining distances s1, s2 on both sides of the isolated main pattern A of the line width (w) of the mask for the deformed illuminating exposure device optimized to the min. pattern pitch P. The line width sw1, sw2 are set narrower than the min. line width P/2 so that the auxiliary patterns are not independently resolved. The distances s1, s2 are set to attain P/<=s1<=(P-sw1) and P/2<=s2((P-sw2) so that the optical path difference between the transmitted light of the auxiliary patterns AS1, AS2 and the transmitted light of the main pattern A varies by about half the wavelength. The light bleeding out of the main pattern A to the dark part is negated by the light bleeding out of the auxiliary patterns AS1, AS2 to the dark part, by which the contrast is stressed and the resolution is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mask for a modified illumination exposure apparatus used for forming a fine pattern.

[0002]

2. Description of the Related Art At present, an exposure apparatus called a stepper is used for forming a fine pattern in a manufacturing process of a fine semiconductor device such as a large scale integrated circuit (LSI). Further, as the light source in that case, g-line (wavelength 436 nm), i-line (wavelength 365 nm) or krypton-fluorine (KrF) excimer laser emitted from a mercury lamp is used.

In these exposure apparatuses, light emitted from a light source is irradiated onto an original plate (hereinafter, represented by a mask) called a mask or reticle by an illumination lens system (including an illumination uniformizing means), and the light passes through the mask. The formed light is image-projected by a projection lens system (generally reduced to 5: 1) onto a semiconductor substrate coated with a photosensitive material (resist). Then, a resist pattern that is not cured by light is removed to obtain a resist pattern. still,
The mask is formed on the glass substrate by an opaque pattern made of chromium oxide film / chromium or the like.

In the conventional exposure apparatus, the pattern shape on the mask and the pattern shape formed on the semiconductor substrate are similar to each other even if they are slightly deformed. However, recently
A mask has been proposed in which an auxiliary pattern for supplying light having a phase different from that of light from the pattern is arranged around the pattern for forming an image to improve the resolution. At that time, the auxiliary pattern is formed into a fine pattern so that it is not resolved by the exposure apparatus used.

As a mask using such an auxiliary pattern, there is a mask disclosed in Japanese Patent Laid-Open No. 3-210560. In this mask, in order to improve the resolution, as shown in FIG. 22, the width W1 (= 0.5 × λ / NA
λ: exposure wavelength, NA: numerical aperture of the exposure apparatus), and a width W2 (= 0.4 × W1 to 0.2) while maintaining a center-to-center distance D (= 1.2 × λ / NA). An auxiliary pattern of 5 × W1) is provided. The above dimensions are on the wafer surface, and the main pattern dimensions are extremely small.

Here, an i-line exposure apparatus with NA = 0.5 (λ = 365 nm) used for the production of a 0.6 μm rule LSI
Consider the case of using the mask disclosed in Japanese Patent Laid-Open No. 3-210560. The main pattern size in this case is 365 nm. However, the limit resolution of currently available i-line resist is about 350 nm. Therefore, the mask using the above auxiliary pattern can be used only near the limit resolution.

Normally, a mask for an exposure apparatus using such a main pattern having a dimension near the critical resolution is not used in an actual production process (it is used up to 0.5 μm in the above i-line exposure apparatus). However, the method using the auxiliary pattern as described above is not practical.

On the other hand, in order to improve the resolution of the exposure apparatus, the transparent portions (chrome openings) of the mask are classified into at least two types so that the phases of light from different types of transparent portions are different. Shift masks have recently begun to be used. This phase shift mask can further improve the resolution of the exposure apparatus as compared with the mask using the above-mentioned auxiliary pattern, but the pattern design and mask formation are complicated, and defect inspection and repair are difficult. .

Therefore, a modified illumination method for improving the resolution by improving the illumination system of the exposure apparatus is being used in some exposure apparatuses. In this modified illumination exposure apparatus, it is necessary to obliquely irradiate the mask with light, and as a filter for oblique irradiation, a ring-shaped annular illumination filter, a four-hole-shaped four-direction filter, or the like has been proposed. .

Unlike the exposure apparatus using the phase shift mask, the above modified illumination exposure apparatus does not require phase control, so that the mask manufacturing is not much different from that of the normal mask, and at least the phase for the line-and-space pattern is used. It is very practical because it can achieve a resolution equivalent to that of an exposure apparatus using a shift mask.

The above modified illumination method will be briefly described below. In the modified illumination method, as shown in FIG.
Illumination light is obliquely incident on the mask. At that time,
The incident angle θ of the illumination light is a line-and-space pattern (hereinafter referred to as the minimum line-and-space) optimized to the minimum pattern pitch P (minimum pitch of resolvable patterns) existing on the mask. The adjacent transparent portions A,
The optical path difference "a" between B or between the transmissive portions B and C is set to be exactly half the exposure wavelength. That is, a
= P · sin θ = λ / 2 is satisfied.

As a result, as shown in FIG. 19 (b), the phases of the adjacent light patterns A ', B'or light patterns B', C'are opposite to each other on the image plane, so that the patterns between the patterns are opposite to each other. The light exuding in the dark part cancels each other out, and the contrast between the bright part and the dark part of the image is emphasized to improve the resolution of the pattern.

[0013]

However, the above modified illumination exposure apparatus also has the following problems. That is, as shown in FIG. 20, in the isolated pattern, there is no light that cancels the light bleeding to the dark part, and therefore the above-described effect cannot be expected. Therefore, the line
In the case of a fine pattern having the same line width in the isolated pattern as compared with the AND space pattern, the image contrast is reduced and the line width controllability for the resist pattern is reduced. Similarly, the pattern located on the outermost side of the line and space pattern does not receive the light of the opposite phase from the outside, so that the resolution is lowered.

In FIG. 19 and FIG. 20, only one incident direction of light is shown for simplification of description.
Incident light from a direction symmetrical to the normal to the mask is also used. Further, as shown in FIG. 21, since the pattern actually extends in two directions orthogonal to each other, illumination in four directions is used. In this case, the incident angle is such that the light from A and C has the opposite phase to the light from B in the figure, and the light from P and R also has the opposite phase to the light from Q. Is set to.

Further, in order to make up for the drawbacks of the modified illumination exposure apparatus as described above, it is conceivable to apply the auxiliary pattern in the above Japanese Patent Laid-Open No. 3-210560 to the mask for the modified illumination exposure apparatus. However, in such a case, the following problems occur.

That is, the same NA as the i-line exposure apparatus described above is used.
= 0.5 and a minimum resolution of 0.35 μm, when the above auxiliary pattern is applied to the i-line modified illumination exposure apparatus, an optimized line-and-space pattern as shown in FIG. 23B, the auxiliary pattern is too far from the main pattern (pitch D between the main pattern and the auxiliary pattern is larger than the pitch of 0.70 μm in FIG.
= 0.876 μm). Therefore, the auxiliary pattern is
0.35 μm with the main pattern adjacent to the main pattern
The area (a) of a part of the auxiliary pattern does not completely fit within the area of the virtual pattern that forms the line-and-space pattern, but extends outside the area of the virtual pattern.

As a result, since the light transmitted through the area (b) in the virtual pattern area of the auxiliary pattern has the opposite phase of the light transmitted through the main pattern, the light bleeding from the main pattern to the dark side is obtained. Can be canceled by the light leaking from the region (B) to the dark part. However, since the light transmitted through the area (a) in the auxiliary pattern has the same phase as the light transmitted through the main pattern, the light bleeding into the dark portion is increased on the contrary. Therefore, as described above, it is impossible to eliminate the drawbacks of the modified illumination exposure apparatus by simply applying the auxiliary pattern in Japanese Patent Laid-Open No. 3-210560 to the modified illumination exposure apparatus mask.

Therefore, an object of the present invention is to provide a mask for a modified illumination exposure apparatus capable of improving the resolution of the outermost pattern of an isolated pattern or a line-and-space pattern even if the modified illumination exposure apparatus has a minimum resolution of 0.35 μm. To provide.

[0019]

In order to achieve the above object, a first invention is a mask for a modified illumination exposure apparatus for transferring a pattern having a minimum pattern pitch P, which is a distance (P +) from another pattern. An auxiliary pattern having the same transmission characteristics as the main pattern is arranged in the vicinity of at least a part of the main pattern having a width of P / 2 or more and arranged with the width S equal to or more than a predetermined value S). P / 2
On the other hand, the shortest distance from the main pattern to the auxiliary pattern is P / 2 or more and (P−S) or less while making the width narrower.

A second invention is a mask for a modified illumination exposure apparatus according to the first invention, wherein the auxiliary pattern is arranged in parallel only on at least a part of a side of the main pattern. Is characterized by.

A third aspect of the present invention is the mask for a modified illumination exposure apparatus according to the first aspect of the present invention, wherein the auxiliary pattern is arranged in parallel to at least a part of the side and end sides of the main pattern. It is characterized by being.

A fourth invention is the mask for modified illumination exposure apparatus of the first invention, wherein the auxiliary pattern is arranged so as to continuously surround at least a part of the main pattern. Is characterized by.

A fifth aspect of the present invention is a mask for a modified illumination exposure apparatus for transferring a pattern having a minimum pattern pitch P, which is arranged at a distance of less than (P + predetermined value S) to P / 2. An auxiliary pattern of width S having the same transmission characteristic as the main pattern is arranged near the outer side of at least one of the two outermost patterns in the main pattern composed of a plurality of patterns having the above widths. The width S of the pattern is made narrower than P / 2, while the distance from the outermost one of the patterns to the auxiliary pattern is P / 2 or more and (PS) or less. Is characterized by.

A sixth aspect of the present invention is a mask for a modified illumination exposure apparatus for transferring a pattern having a minimum pattern pitch P, which comprises a plurality of masks arranged at a distance from each other and having a width of P / 2 or more. An auxiliary pattern having a width S having the same transmission characteristic as that of the main pattern is arranged between two patterns adjacent to each other in the main pattern composed of the patterns and separated by a distance (P + predetermined value S) or more. Width S
Is smaller than P / 2, while the distance from the two adjacent patterns to the auxiliary pattern is P / 2 or more and (P−S) or less.

[0025]

In the first invention, the distance (P +
S) Using a mask for a modified illumination exposure apparatus in which an auxiliary pattern having the same transmission characteristics as the main pattern is arranged in the vicinity of at least a part of the main pattern having a width of P / 2 or more and arranged with keeping the above Then, the modified illumination exposure device exposes the resist. At this time, since the width S of the auxiliary pattern is smaller than the minimum line width P / 2, the exposure process is performed without the auxiliary pattern being resolved.

Further, since the shortest distance from the main pattern to the auxiliary pattern is P / 2 or more and (PS) or less, the light transmitted through at least a part of the main pattern and the auxiliary pattern are The optical path difference from the transmitted light is about half the exposure wavelength. Therefore, the light penetrating at least a part of the main pattern and exuding to the dark part side is canceled by the light penetrating the auxiliary pattern and exuding to the dark part side, and the main pattern on the image plane , The contrast between the bright part corresponding to at least a part of the main part and the dark part around the bright part is emphasized, and the resolution of the main pattern is improved. Thus, the resolution of the isolated pattern, which is the main pattern, is improved.

Further, in the second invention, the main pattern on the image plane is obtained by the same operation as that of the first invention by the auxiliary pattern arranged in parallel only on at least a part of the side of the main pattern. The contrast relating to at least a part of the side of is enhanced. Thus, the resolution of the isolated pattern, which is the main pattern, is improved.

Further, in the third invention, the same operation as in the first invention by the auxiliary pattern arranged in parallel to at least a part of the side and end sides of the main pattern is performed, and the auxiliary pattern is formed on the image plane. The contrast on the sides and edges of the main pattern is enhanced. In this way, the resolution of the isolated pattern, which is the main pattern, is further improved by the four-direction illumination.

Further, in the fourth invention, the main pattern on the image plane is obtained by the same operation as the first invention by the auxiliary pattern arranged so as to continuously surround at least a part of the main pattern. The contrast of at least a part of the side edges and the edge edges is enhanced. Thus, the resolution of the isolated pattern, which is the main pattern, is further improved by the four-direction illumination.

In the fifth invention, the distance (P +
S) By the same operation as the first invention by the auxiliary pattern arranged near the outer side of at least one of the two outermost patterns in the main pattern composed of a plurality of patterns arranged with keeping less than S, The contrast between the bright portion corresponding to the one outermost pattern on the image plane and the surrounding dark portion is emphasized.
In this way, the resolution of the outermost pattern of the minimum line and space pattern is improved.

In the sixth aspect of the invention, the main pattern composed of a plurality of patterns arranged at a distance from each other is arranged between two patterns which are adjacent to each other at a distance (P + S) or more. The same effect as that of the first aspect of the invention by the auxiliary pattern enhances the contrast between the two bright portions corresponding to the two adjacent patterns on the image plane and the dark portion therebetween. Thus, the resolution of the minimum line and space pattern is further improved.

[0032]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. The present invention provides a main pattern (isolated pattern) that is isolated from a pattern in a mask for modified illumination exposure apparatus optimized to a minimum pattern pitch P by a distance P or more, or modified illumination exposure optimized to a minimum pattern pitch P. An auxiliary pattern, which has the same transmission characteristics as the main pattern and cannot be resolved by itself, is placed in the vicinity of at least a part of the outermost pattern (main pattern) in the device line and space pattern with a predetermined distance from the main pattern. By arranging them, the resolution of the modified illumination exposure apparatus mask optimized to the minimum pattern pitch P is improved.

<First Embodiment> FIG. 1 is a diagram showing an arrangement example of an auxiliary pattern for an isolated pattern and a line-and-space pattern in a mask for a modified illumination exposure apparatus of this embodiment. Here, there are two types of pitches of the line-and-space pattern indicating the resolvable pattern, "P1" and "P2". The minimum pattern pitch P in FIG. 1 is "P1". Auxiliary pattern AS1 having line width sw1 separated by distances s1 and s2 from both sides of main pattern A which is a rectangular isolated pattern having line width w in the mask for modified illumination exposure apparatus optimized to minimum pattern pitch P. And an auxiliary pattern AS2 having a line width sw2 is arranged.

Both the auxiliary patterns AS1 and AS2 have the minimum line width P / P2 so that the line widths sw1 and sw2 are not resolved by themselves.
It is set to be sufficiently narrower than 2, and in this embodiment, P /
It is set to 4. Further, the distance s1 between the main pattern A and the auxiliary pattern AS1 and the distance s2 between the main pattern A and the auxiliary pattern AS2 are both P / 2 ≦ s1 ≦ (P
-Sw1) and P / 2≤s2≤ (P-sw2). This condition is that, when considering a virtual pattern which is adjacent to the main pattern A and forms the minimum line-and-space pattern together with the main pattern A, the auxiliary patterns AS1 and AS2 are regions of the virtual pattern. It is a condition to get inside completely. In other words, the above condition is that the auxiliary patterns AS1, AS2 are as shown in FIG.
The optical path difference "b" between the light passing through the main pattern A and the light passing through the main pattern A is about half the exposure wavelength (the phase difference is about 180).
It is a necessary condition to become (degree). In this embodiment, both the distance s1 and the distance s2 are set to P / 2.

Further, the present embodiment is applied to a mask for minimum line and space 0.35 μm (P = 0.7 μm) so that the line widths of the auxiliary patterns AS1 and AS2 are sw1 = sw2 = 0.175 μm.
When set to, sw1 = sw2 does not always hold because the mask actually formed has a line width variation of about 0.03 nm in terms of projected pattern conversion. Even if the distances s1 and s2 from the main pattern A are set to s1 = s2 = 0.35 μm, s1 = s2 does not hold. Further, even if the lengths of the auxiliary patterns AS1 and AS2 are set to be the same as the length of the main pattern A, a variation of about 0.03 μm to 0.05 μm occurs on an actual mask. It should be noted that each of the above dimensions is a dimension on the image plane and is the same in each of the following embodiments.

Using the mask for modified illumination exposure apparatus formed as described above, a two-way illumination system aiming at a minimum pitch of 0.7 μm was attached to an i-line modified illumination exposure apparatus with NA = 0.54 to provide a negative resist. Exposed. As a result, the linearity of the pattern width on the mask with respect to the resist pattern width related to the main pattern A was only up to 0.4 μm in the case of no auxiliary pattern, whereas by providing the auxiliary patterns AS1 and AS2. It was secured up to 0.35 μm. Therefore, the auxiliary pattern AS as described above
1 and line widths sw1 and sw2 and distances s1 related to the auxiliary pattern AS2
The linearity of the line width in the main pattern A can be improved regardless of variations in s2 and length.

Further, the side wall in the cross-sectional shape of the obtained resist pattern relating to the main pattern A becomes closer to vertical, and the pattern width controllability when etching is performed using this resist pattern can be improved.

As described above, in this embodiment, the upper minimum line and
Since the auxiliary patterns AS1 and AS2 are accurately arranged in the area of the virtual pattern that forms the space pattern,
Even if the minimum pattern pitch P is 0.7 μm, the optical path difference between the light transmitted through the main pattern A and the light transmitted through the auxiliary patterns AS1 and AS2 can be set to about half the exposure wavelength. Therefore, the light bleeding from the main pattern A to the dark portion on the image plane is completely canceled by the light bleeding from the auxiliary patterns AS1 and AS2 to the dark portion.

That is, by using the modified illumination exposure apparatus mask of this embodiment, the resolution of an isolated pattern can be improved even with an i-line modified illumination exposure apparatus having a minimum resolution of 0.35 μm. Therefore, it is possible to improve the linearity of the width of the opening of the fine resist pattern and to verticalize the side wall.

In this embodiment, the bidirectional illumination is adopted, but as shown in FIG. 3, if the target minimum pitch is the same, the same pattern arrangement may be applied to the four-directional illumination. You can In the above embodiment, the auxiliary patterns AS1 and AS2 are arranged on both sides of the main pattern A. However, when it cannot be arranged on both sides of the main pattern A due to the balance with other patterns, the effect can be obtained by arranging it on only one side.

It is not necessary to dispose the auxiliary pattern along the entire main pattern A, and as shown in FIG. 9, the auxiliary pattern AS1, AS3 may be arranged. Also in this case, the auxiliary pattern AS for the main pattern A
The arrangement rule of 1, AS3 is as described above. However, the distance s10 between the base of the main pattern A and the ends of the auxiliary patterns AS1 and AS3 needs to be P / 2 or more.

<Second Embodiment> FIG. 4 shows an arrangement example of auxiliary patterns for isolated lines in the case of four-direction illumination. In this embodiment, the auxiliary patterns AS3 and AS4 are arranged not only on both sides of the main pattern A but also on both sides. The line widths sw3 and sw4 of the auxiliary patterns AS3 and AS4 satisfy the same conditions as the line widths sw1 and sw2 of the auxiliary patterns AS1 and AS2. The length of the auxiliary patterns AS3 and AS4 is
It is preferable that the line width w of the main pattern A is approximately equal to or longer than that.

Therefore, as a specific example of this embodiment, the first
As in the case of the embodiment, the auxiliary patterns AS1, AS2,
The line width of AS3 and AS4 is sw1 = sw2 = sw3 = sw4 = 0.175μ
The distance was set to m and the distance was set to s1 = s2 = s3 = s4 = 0.35 μm. The length of the auxiliary patterns AS3 and AS4 is (line width w of the main pattern A + 0.2 μm).

When the negative resist is exposed by the i-line modified illumination exposure apparatus having the same NA = 0.54 as in the first embodiment using the modified illumination exposure apparatus mask to which the auxiliary patterns AS3 and AS4 are added as described above, Improves the contrast at the end of the main pattern A, which is an isolated pattern, and makes the side wall slope at the end of the opening of the resist pattern closer to vertical, thus improving the line width controllability after etching.

It is not necessary to arrange the auxiliary pattern along all of the main pattern A, and as shown in FIG. 10, only in the periphery of the main pattern A where the line width control needs to be precise. You may arrange. Also in this case, the arrangement rules of the auxiliary patterns AS1, AS2, AS3 with respect to the main pattern A are as described above. However, the distance s10 between the base of the main pattern A and the ends of the auxiliary patterns AS1 and AS3 needs to be P / 2 or more.

<Third Embodiment> FIG. 5 shows an arrangement example in which the auxiliary pattern completely surrounds the main pattern. In this embodiment, the line width of the straight line portion of the auxiliary pattern AS is sw1 = s.
Set w2 = sw3 = sw4 = 0.175 μm, and set the distance between each straight part of the main pattern A and the auxiliary pattern AS to s1 = s2 = s3 = s4
= 0.35 μm. However, these parameters only have to satisfy the conditions described in the first embodiment, and the above parameters are merely examples of this embodiment even if they are tired.

It is not necessary to arrange the auxiliary pattern along the entire main pattern A, and as shown in FIG. 11, the auxiliary pattern AS is provided only in a portion of the main pattern A where the line width control needs to be precise. You may arrange. Also in this case, the arrangement rule of the auxiliary pattern AS with respect to the main pattern A is as described above. However, the distance s10 between the base of the main pattern A and the end of the auxiliary pattern AS is P / 2.
It must be above.

<Fourth Embodiment> FIG. 6 shows an arrangement example of an auxiliary pattern for an isolated pattern having a bent portion. In this embodiment, auxiliary patterns AS1 and AS2 having bent portions are provided along the main pattern A having bent portions. The line widths sw1 and sw2 of the auxiliary patterns AS1 and AS2 satisfy the conditions described in the first embodiment. The distances s1 and s2 between the auxiliary patterns AS1 and AS2 and the main pattern A are also the first
The conditions described in the embodiment are satisfied. When the isolated pattern having the bent portion (main pattern A) has an end, the end of the main pattern A may be completely surrounded by the auxiliary pattern AS as shown in FIG. 7.

<Fifth Embodiment> In this embodiment, FIG.
As shown in FIG. 5, the linear auxiliary patterns AS1, AS2, AS3, AS4 having no bent portion are provided for the isolated pattern (main pattern A) having a bent portion. The line widths sw1, sw2, sw3, sw4 of the auxiliary patterns AS1, AS2, AS3, AS4 satisfy the conditions described in the first embodiment. Further, the distances s1, s2, s3, s4 between the auxiliary patterns AS1, AS2, AS3, AS4 and the main pattern A also satisfy the conditions described in the first embodiment.

<Sixth Embodiment> FIG. 12 shows an arrangement example of an auxiliary pattern with respect to an isolated pattern which is a substantially square contact hole C. In this embodiment, the horizontal width w1 and the vertical width w2
Line width sw that surrounds the contact hole C at a distance s1
One auxiliary pattern CS is arranged. However, the direction of the auxiliary pattern CS needs to be inclined by about 45 degrees with respect to the incident directions of the illumination light from the four directions. Further, the line width sw1 is set sufficiently smaller than the minimum line width P / 2 so that the auxiliary pattern CS cannot be resolved alone, and in this embodiment, it is set to P / 4.

Further, the distance s1 between the contact hole C and the auxiliary pattern CS is P / 2 ≦ s1 ≦ (P-sw
It is set to be 1). Under this condition, as described in the first embodiment, the optical path difference between the light passing through the auxiliary pattern CS and the light passing through the contact hole C is about half the exposure wavelength (about 180 degrees in phase difference). This is a condition necessary for this, and is set to P / 2 in this embodiment.

As a concrete example of this embodiment, the minimum line-and-space mask for 0.35 μm (P = 0.7 μm)
In this case, the auxiliary pattern having the line width sw1 = 0.175 μm is arranged while maintaining the distance s1 = 0.35 μm with respect to the contact hole C having the width w1 = the height w2 = 0.4 μm.

NA is obtained by using the mask thus constructed.
= 0.5 μm for i-line modified illumination exposure system of 0.54
As a result of attaching a four-direction illumination system targeting m and exposing the positive resist, the depth of focus capable of opening a 0.4 μm hole is increased from 1.0 μm to 1.3 μm as compared with the case without the auxiliary pattern CS.

In this embodiment, the line width sw1 of the auxiliary pattern CS and the distance s1 between the auxiliary pattern CS and the contact hole C are always constant, but the pattern actually formed is designed due to variations in the mask manufacturing process. It's not a street. However, that is not a problem at all. Therefore, in this embodiment, the line width sw1 of the auxiliary pattern CS and the distance s1 between the auxiliary pattern CS and the contact hole C do not necessarily need to be completely constant in the length direction.

Further, in the present embodiment, one auxiliary pattern CS is arranged so as to surround the contact hole C, but as shown in FIG. 13, the line width sw1 is separated from the contact hole C by the distance s1. The contact holes C may be surrounded by arranging the four rectangular auxiliary patterns CS1, CS2, CS3, CS4. However, in that case, similar to FIG. 12, the auxiliary patterns CS1, CS2, CS3, CS4
It is necessary that each of the arrangement directions is inclined by about 45 degrees with respect to the incident direction of the illumination light from each of the four directions. In FIG. 13, the length of the auxiliary patterns CS1, CS2, CS3, CS4 is adjusted to the width w1 or the vertical width w2 of the contact hole C. However, as shown in FIG. It may be longer than the length of the width w1 and the height w2.
Further, as shown in FIG. 15, the contact hole C may be shorter than the horizontal width w1 and the vertical width w2.

<Seventh Embodiment> FIG. 16 shows an arrangement example of auxiliary patterns for the outermost pattern in the minimum line-and-space pattern for a modified illumination exposure apparatus.
In this embodiment, when the patterns A1, A2, A3, A4 having the line widths w1, w2, w3, w4 are formed with the inter-pattern distances d1, d2, d3 to form the main pattern, The auxiliary patterns AS1 and AS2 having the line widths sw1 and sw2 are arranged at the distances s1 and s2 from the patterns A1 and A4, respectively.

Line widths sw1 and s of the auxiliary patterns AS1 and AS2
Both w2 are set sufficiently smaller than the minimum line width P / 2 so that the auxiliary patterns AS1 and AS2 are not resolved by themselves, and are set to P / 4 in this embodiment. Further, the distance s1 between the outermost pattern A1 and the auxiliary pattern AS1 and the distance s2 between the outermost pattern A4 and the auxiliary pattern AS2 are both P / 2 ≦ s1 ≦ (P−sw1) and P / sw.
It is set so that 2 ≦ s2 ≦ (P−sw2). This condition is that the auxiliary patterns AS1 and AS2 completely enter the area of the virtual pattern that forms the minimum line-and-space pattern together with the outermost patterns A1 and A4, and the auxiliary pattern AS1 is transmitted. Path difference between the incident light and the light transmitted through the pattern A1 and the auxiliary pattern AS2
This is a condition necessary to make the optical path difference between the light passing through the pattern A4 and the light passing through the pattern A4 approximately half a wavelength of the exposure wavelength (approximately 180 degrees in the phase difference). In this embodiment, the distance s1 and the distance s2 are set. Both are set to P / 2.

When the minimum line width of the auxiliary patterns AS1 and AS2 is αP, the inter-pattern distances d1, d2 and d3 must all be smaller than (1 + α) P. If the inter-pattern distance d3 is (1 + α) P or more, another auxiliary pattern can be inserted between the pattern A3 and the pattern A4.

That is, when the range of the inter-pattern distance d3 is (1 + α) P ≦ d3 <(1.5 + 2α) P, as shown in FIG. 17, an auxiliary pattern is provided between the pattern A3 and the pattern A4. AS3 can be inserted. At that time, the pattern A3 and the auxiliary pattern AS3
And the distance s4 between the outermost pattern A4 and the auxiliary pattern AS3 are both P / 2 ≦ s3 ≦ (P−sw3)
Since it is necessary to satisfy the conditions of P / 2 ≦ s4 ≦ (P−sw3), the minimum value of the inter-pattern distance d3 is (1 + α) P.

When the range of the inter-pattern distance d3 is d3 ≧ (1.5 + 2α) P, as shown in FIG. 18, two auxiliary patterns AS3, A3 are provided between the pattern A3 and the pattern A4. AS4 can be inserted. At that time, the distance s3 between the pattern A3 and the auxiliary pattern AS3 and the distance s5 between the outermost pattern A4 and the auxiliary pattern AS4 are both P / 2 ≦ s.
It is necessary to satisfy the conditions of 3 ≦ (P−sw3) and P / 2 ≦ s5 ≦ (P−sw4), and the distance s4 between both auxiliary patterns AS3 and AS4.
Must satisfy the condition of s4 ≧ P / 2, the minimum value of the inter-pattern distance d3 is (1.5 + 2α) · P.

The number of each pattern constituting the main pattern shown in the above example is not less than (1 + α) P between adjacent two patterns and is (1.5 + 2α) regardless of the present invention.
If there is a space less than P, one auxiliary pattern can be added to that space. Alternatively, if there is a space of (1.5 + 2α) P or more between two adjacent patterns, two auxiliary patterns can be added to the space. In that case, it can be considered that two independent main patterns are adjacent to each other.

[0062]

As is clear from the above, the mask for the modified illumination exposure apparatus according to the first aspect of the invention has a distance from other patterns.
An auxiliary pattern is arranged in the vicinity of at least a part of a main pattern having a width of P / 2 or more and kept at (P + S) or more, and the width S of this auxiliary pattern is made narrower than P / 2, while Since the shortest distance from the pattern to the auxiliary pattern is P / 2 or more and (P−S) or less, the auxiliary pattern is not resolved by itself.
Moreover, even if the minimum pattern pitch P is 0.7 μm, the auxiliary pattern can be accurately arranged in the area of the virtual pattern that forms the minimum line-and-space pattern together with at least a part of the main pattern.

That is, the minimum pattern pitch P is 0.
Even if it is 7 μm, the optical path difference between the light transmitted through at least a part of the main pattern and the light transmitted through the auxiliary pattern can be set to about half the exposure wavelength, and the contrast of the image of at least a part of the main pattern can be increased. Can be improved to improve the resolution of the isolated pattern. Therefore, according to the present invention, the resolution of an isolated pattern can be improved even when a modified illumination exposure apparatus with a minimum resolution of 0.35 μm is used.

Further, in the mask for the modified illumination exposure apparatus of the second invention, since the auxiliary pattern is arranged parallel to only at least a part of the side of the main pattern, the main pattern (isolated pattern) is not formed. The resolution of at least some sides can be improved.

Further, in the modified illumination exposure apparatus mask of the third invention, since the auxiliary pattern is arranged in parallel to at least a part of the side and the side of the main pattern, the main pattern ( It is possible to improve the resolution of at least a part of the side and end sides of the isolated pattern). Therefore, by using the present invention, the width of the resist pattern in the contact hole can be accurately controlled.

Further, in the mask for modified illumination exposure apparatus of the fourth invention, since the auxiliary pattern is arranged so as to continuously surround at least a part of the main pattern, the main pattern (isolated pattern) is illuminated by four-direction illumination. The resolution of can be further improved. Therefore, by using this width, the width of the resist pattern in the contact hole can be controlled more accurately.

Further, the mask for modified illumination exposure apparatus according to the fifth aspect of the present invention includes at least two outermost patterns in a main pattern composed of a plurality of patterns arranged at a distance less than (P + S). An auxiliary pattern having a width S is arranged in the vicinity of one outer side to make the width S of the auxiliary pattern narrower than P / 2, while the distance from the one outermost pattern to the auxiliary pattern is P / 2. Since it is set to be equal to or more than and equal to or less than (P−S),
Even when the modified illumination exposure apparatus having the minimum resolution of 0.35 μm is used, the resolution of the outermost pattern of the line and space pattern can be improved.

Further, the mask for modified illumination exposure apparatus according to the sixth aspect of the present invention is provided with two masks adjacent to each other in a main pattern composed of a plurality of patterns arranged at a distance from each other with a distance of (P + S) or more. An auxiliary pattern having a width S is arranged between the patterns to make the width S of the auxiliary pattern narrower than P / 2, while the distance from the adjacent two patterns to the auxiliary pattern is P / 2 or more. And, since it is set to be (P−S) or less, there is a distance in the main pattern.
It is possible to improve the contrast of images of two patterns that are adjacent to each other with a distance of (P + S) or more. Therefore, according to the present invention, the resolution of the line and space pattern can be further improved even when the modified illumination exposure apparatus having the minimum resolution of 0.35 μm is used.

In the above description, the case of the two-direction illumination and the four-direction illumination has been described, but a certain effect can be obtained for the annular illumination.

[Brief description of drawings]

FIG. 1 is a diagram showing an arrangement example of auxiliary patterns in the case of two-direction incidence on a rectangular main pattern which is an isolated pattern in a mask for a modified illumination exposure apparatus of the present invention.

FIG. 2 is an explanatory diagram of a contrast improving effect by an auxiliary pattern.

FIG. 3 is a diagram showing an arrangement example of auxiliary patterns in the case of four-direction incidence on a rectangular main pattern which is the same isolated pattern as in FIG. 1;

FIG. 4 is a diagram showing an arrangement example of auxiliary patterns different from FIG. 3 in the case of four-direction incidence on a rectangular main pattern which is an isolated pattern.

FIG. 5 is a diagram showing an arrangement example of auxiliary patterns different from FIGS. 3 and 4 in the case of four-direction incidence on a rectangular main pattern which is an isolated pattern.

FIG. 6 is a diagram showing an arrangement example of auxiliary patterns with respect to a main pattern having a bent portion which is an isolated pattern.

7 is a diagram showing an arrangement example of an auxiliary pattern different from that of FIG. 6 with respect to a main pattern having a bent portion which is an isolated pattern.

8 is a diagram showing an arrangement example of an auxiliary pattern for a main pattern having a bent portion which is an isolated pattern, which is different from FIGS. 6 and 7. FIG.

FIG. 9 is a diagram showing an arrangement example of auxiliary patterns for a part of a main pattern.

FIG. 10 is a diagram showing an arrangement example of an auxiliary pattern for a part of the main pattern, which is different from FIG. 9;

FIG. 11 is a diagram showing an arrangement example of an auxiliary pattern for a part of the main pattern, which is different from FIGS. 9 and 10.

FIG. 12 is a diagram showing an arrangement example of auxiliary patterns for contact holes which are isolated patterns.

13 is a diagram showing an arrangement example of an auxiliary pattern for a contact hole which is an isolated pattern, which is different from FIG.

FIG. 14 is a diagram showing an arrangement example of an auxiliary pattern for a contact hole which is an isolated pattern, which is different from FIGS. 12 and 13.

FIG. 15 is a view showing an arrangement example of auxiliary patterns for contact holes which are isolated patterns, which is different from FIGS. 12, 13 and 14.

FIG. 16 is a diagram showing an arrangement example of auxiliary patterns for line and space patterns.

FIG. 17 is a diagram showing an arrangement example of an auxiliary pattern for a line and space pattern different from that in FIG.

FIG. 18 is a diagram showing an arrangement example of an auxiliary pattern for a line and space pattern, which is different from FIGS. 16 and 17.

FIG. 19 is an explanatory diagram of a modified illumination method in a line and space pattern.

FIG. 20 is an explanatory diagram of a modified illumination method for an isolated pattern.

FIG. 21 is an explanatory diagram of an illumination method for a mask having a pattern extending in two orthogonal directions.

FIG. 22 is a diagram showing an example of a mask using a conventional auxiliary pattern.

FIG. 23 is an explanatory diagram of a problem when the mask using the conventional auxiliary pattern shown in FIG. 22 is used in a modified illumination exposure apparatus.

[Explanation of symbols]

 A ... Main pattern (isolated pattern), A1 to A4 ... Line and space pattern, AS, AS1 to AS4, CS1 to CS4 ... Auxiliary pattern, C ... Contact hole.

Claims (6)

[Claims] 1. A mask for a modified illumination exposure apparatus for transferring a pattern having a minimum pattern pitch P representing the minimum pitch of a resolvable pattern, the mask being at a distance (P + predetermined value S) or more from another pattern. An auxiliary pattern having the same transmission characteristics as the main pattern is arranged in the vicinity of at least a part of the main pattern having the width of P / 2 or more, and the width S of the auxiliary pattern is narrower than P / 2. On the other hand, P is the shortest distance from the main pattern to the auxiliary pattern.
A mask for a modified illumination exposure apparatus, wherein the mask is not less than / 2 and not more than (PS). 2. The modified illumination exposure apparatus mask according to claim 1, wherein the auxiliary pattern is arranged in parallel only on at least a part of a side of the main pattern. Mask for illumination exposure equipment. 3. The mask for a modified illumination exposure apparatus according to claim 1, wherein the auxiliary pattern is arranged in parallel to at least a part of a side edge and an edge of the main pattern. Mask for modified illumination exposure equipment. 4. The modified illumination exposure apparatus mask according to claim 1, wherein the auxiliary pattern is arranged so as to continuously surround at least a part of the main pattern. Mask for illumination exposure equipment. 5. A mask for a modified illumination exposure apparatus for transferring a pattern having a minimum pattern pitch P representing a minimum pitch of a resolvable pattern, the masks being arranged at a distance (P + predetermined value S) from each other. Being P /
An auxiliary pattern having a width S having the same transmission characteristic as that of the main pattern is arranged in the vicinity of the outer side of at least one of the two outermost patterns in the main pattern composed of a plurality of patterns having two or more widths, While making the width S of this auxiliary pattern narrower than P / 2, the distance from the outermost one of the patterns to the auxiliary pattern is P / 2 or more and (PS) or less. A mask for a modified illumination exposure apparatus, which is characterized in that 6. A mask for a modified illumination exposure apparatus for transferring a pattern having a minimum pattern pitch P that represents the minimum pitch of a resolvable pattern, the mask being arranged at a distance from each other and having a pitch of P / 2 or more. Distance in the main pattern composed of multiple patterns with width
An auxiliary pattern having a width S having the same transmission characteristic as the main pattern is arranged between two patterns adjacent to each other with a distance of (P + predetermined value S) or more, and the width S of the auxiliary pattern is made narrower than P / 2. A mask for a modified illumination exposure apparatus, wherein the distance from the two adjacent patterns to the auxiliary pattern is P / 2 or more and (P−S) or less.