JP3215394B2 - Method for manufacturing electrode wiring conduction hole and method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photomask used for manufacturing a semiconductor device and the like, and more particularly to a method for manufacturing an electrode wiring conductive hole of a semiconductor element using a photomask subjected to a process for changing the phase of illumination light, and a method for manufacturing a semiconductor device. About the method.

[0002]

2. Description of the Related Art As one of conventional techniques for improving the resolution of an exposure apparatus for transferring a mask pattern, there is a method of introducing a phase into light transmitted through a mask. For example, Japanese Patent Publication 62-50
In JP-A-81111, a transparent film for changing the phase is formed on at least one of the light transmitting portions on both sides sandwiching the opaque portion.
According to this method, the resolution can be remarkably increased by using the same lens as the conventional one.

In Japanese Patent Application Laid-Open No. 62-67547, as a means for improving the resolution of a single light transmitting portion, a light having a resolution lower than the resolution limit where the phase of the transmitted light is inverted on both sides of the single light transmitting portion. A transmission section is provided.

Furthermore, Japanese Patent Application Laid-Open No. 53-5572 proposes a photomask having a phase difference between a light transmitting portion and a translucent portion as a stable photomask having a low level of diffraction distortion.

[0005]

In the above prior art, it is necessary to form a transparent film for changing the phase of transmitted light, that is, a so-called phase shifter, after preparing a normal transmission type mask. Further, the phase shifters need to be arranged such that the phases of the light passing through the adjacent transmission sections are inverted from each other. Therefore, when arranging a phase shifter on a complex element pattern, it may be difficult to arrange the shifter. Trial and error and advanced study are required to efficiently arrange the shifter, and a great deal of labor is required. Was needed.

Also, the number of mask manufacturing steps has been doubled as compared with the prior art, and the occurrence of defects and a decrease in yield accompanying the increase in the number of steps have been serious problems. In addition, the repair of the defect of the transparent film requires a lot of labor, which has been a major obstacle to practical use.

[0007] A first object of the present invention is to form a small through hole for an electrode wiring or to form a fine pattern and reduce the rate of occurrence of poor resolution. It is to provide a manufacturing method and a method for manufacturing a semiconductor device.

[0008]

[0009]

[0010]

[0011]

According to the present invention, there is provided a method of manufacturing a conductive hole for an electrode wiring, comprising the steps of: forming a translucent region having a transmittance of exposure light of 30% or less and a light shielding region for forming an alignment mark portion or a detection window pattern; A first light transmitted through the translucent area, and a second light having a phase opposite to that of the first light transmitted through an opening provided in the translucent area.
Is projected through a lens to transfer a hole pattern for an electrode wiring conduction hole to a thin film of a photosensitive material on a wafer.

A method of manufacturing a semiconductor device according to the present invention uses a substrate having a translucent region having a transmittance of exposure light of 30% or less and a light shielding region for forming an alignment mark portion or a detection window pattern. A first light transmitted through a transparent area;
By projecting, through a lens, the first light transmitted through the opening provided in the translucent region and the second light having the opposite phase through a lens, a hole pattern for an electrode wiring conduction hole is formed on the wafer. This is to be transferred to a thin film of the photosensitive material above.

Further, a method of manufacturing a semiconductor device according to the present invention
Assuming that a region transparent to exposure light, a translucent region having a transmittance of 30% or less when the transmittance of the transparent region is 100%, and a positioning mark portion or a detection window pattern. By forming a light-shielding region, the light transmitted through the transparent region and the light transmitted through the translucent region are transmitted through a first substrate, which is inverted with respect to the light, and projected through a lens. And transferring a hole pattern for an electrode wiring conduction hole to a photosensitive thin film on a wafer.

Further, in the method of manufacturing a semiconductor device according to the present invention, there is provided a method of manufacturing a semiconductor device, comprising: a translucent region having a transmittance to exposure light of 30% or less; a transparent region provided in the translucent region; Part or a light-shielding region forming a detection window pattern, and transmitting light to the first substrate in which the phase of light transmitted through the transparent region is inverted with respect to the phase of light transmitted through the translucent region. Forming a hole pattern by projecting a hole pattern for an electrode wiring conduction hole formed on the first substrate through a lens onto a second substrate.

Further, a method of manufacturing a semiconductor device according to the present invention
A step of forming a thin film of a photosensitive material on a first substrate; a first region; and a second region having a transmittance of 30% or less, where the transmittance of light in the first region is 100%. And a light-shielding region forming an alignment mark portion or a detection window pattern, wherein a phase of light transmitted through the first region is formed to be inverted from a phase of light transmitted through the second region. Irradiating the second substrate with light, and projecting a hole pattern for an electrode wiring conduction hole through the lens on the first substrate using the first region and the second region; and Developing the first substrate to form a hole pattern.

In the present invention, the translucent layer has at least one translucent film, and may be a composite film further including a transparent film. That is, any material may be used as long as it is translucent as a whole and generates a phase difference between the translucent layer and the transparent region.

Since the light passing through the translucent film has a phase inverted with respect to the light passing through the light transmitting portion, the phase is inverted at the boundary, and the light intensity at the boundary approaches zero. As a result, the ratio of the intensity of the light that has passed through the light transmitting portion and the intensity of the light at the pattern boundary becomes relatively large, and a light intensity distribution with a higher contrast than that of the conventional method can be obtained.

This will be described with reference to the drawings. First, the conventional method will be described with reference to FIG. FIG. 2A is a cross-sectional view of a conventional photomask, wherein 1 is a glass substrate, and 2 is a Cr film as a light shielding film. The amplitude distribution of the light transmitted through the light transmitting portion 3 has the same reference numeral as shown in FIG. When this light is projected on a wafer through a lens, the light intensity is distributed to a position immediately below the light shielding portion as shown in FIG. 2C.
Therefore, it has been difficult to form a fine pattern by the conventional method.

The present invention will be described with reference to FIG.
FIG. 1A is a cross-sectional view of an example of the photomask of the present invention. 1 is a glass substrate and 4 is a translucent film. Translucent film 4
T = λ / a (n−1) (where λ is the wavelength of the exposure light, n is the refractive index of the translucent film,
a is a value in the range of 1.3 ≦ a ≦ 4). The amplitude distribution of the light transmitted through this mask is
As shown in FIG. 1B, while the light passing through the light transmitting portion 3 has a positive sign, the phase of the light passing through the translucent film 4 is inverted to have a negative sign. When this light is projected on the wafer through a lens, the phase is inverted at the boundary between the light transmitting part 3 and the translucent film 4 as shown in FIG. Become. Therefore, the spread of the light intensity distribution is suppressed, and a fine pattern with high contrast can be formed.

[0020]

Embodiments of the present invention will be described below.

(Embodiment 1) A photomask having the structure shown in FIG. 1 was manufactured as a photomask according to a first embodiment of the present invention. FIG. 1A is a sectional view of a photomask. 1 is a glass substrate and 4 is a translucent film. The thickness of the translucent film 4 is t = λ / a (n−1) (where λ is the wavelength of the exposure light, n is the refractive index of the translucent film,
a is a value in the range of 1.3 ≦ a ≦ 4). The exposure wavelength is i-line (365n) of a mercury lamp.
m) was used. Here, the translucent film 4 was formed by adding a light absorbing agent to coated glass. Since the refractive index of the glass to exposure light was about 1.45, the thickness of the applied glass was about 420 nm. At this time, the addition amount of the light absorbing agent was adjusted so that the transmittance of the exposure light became 15%. The setting of the transmittance needs to be determined in consideration of the sensitivity and the photosensitive characteristics of the resist used, and is not limited to 15%, but is preferably 1% or more to obtain the effect of the present invention. Further, the upper limit of the transmittance is desirably about 50% in consideration of the practical process variation and the like, but the effect can be obtained with more than this value. More effective is in the range of 5 to 30%. The transparent area pattern formed a single hole, dot, space or line pattern, respectively.

In order to obtain the effect of the present invention, the thickness t of the translucent film is desirably in the range of 1.3 ≦ a ≦ 4 where t = λ / a (n−1). Other than the above, a slight contrast improvement effect can be obtained. Further, the material of the translucent film 4 is not limited to coated glass, and a desired transmittance can be obtained, such as an organic film or an inorganic film, and the phase of the transmitted light is substantially equal to the phase of the light transmitted through the light transmitting portion 3. Any material that can be inverted can be used. Also,
Although the structure of the mask is such that the translucent film 4 is formed of a single film in the above embodiment, the present invention is not limited to this.

By using this photomask, the light intensity of the transmitted light becomes almost 0 immediately below the boundary between the light transmitting portion 3 and the translucent film 4, as shown in FIG. 1 (c). The spread of the intensity distribution was suppressed, and a fine pattern with high contrast was formed.

(Embodiment 2) In the second embodiment, the structure of the translucent layer is a multilayer film as shown in FIG. A thin Cr film 6 and a coated glass film 7 were deposited on the glass substrate 1, and a desired pattern portion was removed. In this case, the transmittance was adjusted to 1% with the thin Cr film 6 and the phase difference with the transmission portion was adjusted with the coated glass 7. The transmittance of the thin Cr film 6 to exposure light may be in the range of 1 to 50%. The thickness of the coating glass film 7 may be substantially the same as the thickness limitation of the translucent film 4 shown in the first embodiment, but a thin Cr film is used in order to set the phase difference of 180 ° more precisely. The phase shift of the light passing through No. 6 was also considered. That is, in this embodiment, the translucent layer is composed of the thin Cr film 6 and the coated glass film 7, the thickness of the thin Cr film 6 is determined so that the transmittance is 1%, and the thickness of the coated glass film 7 is reduced.

[0025]

(Equation 1)

(Where d _i and n _i are the thickness and refractive index of the i-th film constituting the translucent layer, m is the number of the films constituting the translucent layer, 2 in this embodiment, and λ is The wavelength of exposure light, φ is a value in the range of 1/4 ≦ φ ≦ 3/4). With this structure, the same effect as in the first embodiment was obtained.

(Embodiment 3) In the third embodiment,
As shown in FIG. 4, a thin Cr film 6 was formed on the glass substrate 1, the thin Cr film 6 was removed in a desired pattern, and then the glass substrate 1 was etched to a desired depth. The thin Cr film 6 has a thickness of 40 nm or less, and has a transmittance for exposure light of 1 to 50% as described in the first embodiment.
It is preferable to adjust the range. In this embodiment, it is 1%. The etching depth is the same as the film thickness limitation of the coating glass film 7 shown in the second embodiment, and the phase of light transmitted through the thin Cr film 6 is set in order to set the phase difference of 180 ° with high accuracy. It was determined in consideration of the deviation.

When it is difficult to control the etching depth of the glass substrate 1, a structure as shown in FIG. 5 may be used. A transparent etching stopper 8 made of ITO is provided on a glass substrate 1, a transparent film 9 is provided thereon, and a thin Cr film 6 is provided thereon. The same effects as in the first embodiment were obtained with the structures of FIGS.

(Embodiment 4) The fourth embodiment has a structure in which the problems in processing of the first embodiment are solved. Although the translucent film 4 in FIG. 1 uses coated glass, this material and the glass substrate 1 are almost the same, and the translucent film 4 is etched with a hydrofluoric acid-based solution or the like.
_In the case of processing by dry etching using a _four- system gas or the like, sufficient selectivity cannot be obtained. Therefore, advanced etching control is required. On the other hand, in the present embodiment, as shown in FIG. 6, an etching stopper 8 is arranged between the glass substrate 1 and the translucent film 4. Here, a silicon nitride film is used, but the present invention is not limited to this.

Further, when there is no conductive material on the glass substrate, a charge-up phenomenon occurs due to the pattern formation by the electron beam, and a problem such as a displacement of the pattern occurs. It is also effective to form a film. When charge-up is prevented by other methods, it is not necessary to use a conductive film. The thickness of the translucent film 4 was the same as described above.

As described above, the mask structure of the present invention needs to be adjusted so that the phases of the light passing through the light transmitting portion and the translucent portion are inverted. It is also effective to combine the structure of the present invention in the same substrate as a normal mask or a conventional phase shift mask. That is, when the alignment mark portion used for aligning the position of the exposure apparatus and the mask and the detection window pattern used for aligning the position of the mask and the wafer are formed of a normal light-shielding film, compared with the case where a translucent film is used. As the detection signal, a high SN ratio was obtained.

Further, the effect of the present invention is effective for forming a hole pattern, and a 0.4 μm diameter hole pattern can be formed in an optical system in which the conventional formation of a 0.5 μm diameter hole pattern has been limited. Furthermore, it was also confirmed that the resolution degradation due to the focal position shift was small.

Further, when the photomask of the present invention described in each of the above embodiments was used for forming the electrode wiring conductive hole of the semiconductor element, a conductive hole smaller by 0.1 μm than before could be formed. Further, with the improvement in the depth of focus, the occurrence rate of the resolution failure was also significantly improved.

Needless to say, the effect of the present invention does not depend on the exposure wavelength. In the above embodiment, the exposure wavelength is i
Although the example using the line (365 nm) is shown, the wavelength is not limited to this. Similar results were obtained with g-line (436 nm), KrF excimer laser light, ArF excimer laser light, and the like.

[0035]

According to the present invention, a small electrode wiring hole can be formed in a semiconductor device.

According to the present invention, a finer pattern can be formed as compared with a conventional transmission mask. Also, the manufacturing process of the photomask is almost the same as that of the conventional transmissive mask, and the process is greatly simplified as compared with the conventional phase shift mask.

Further, as a result of fabricating a semiconductor device using the photomask of the present invention, a pattern can be made finer and a device area can be reduced as compared with a conventional photomask. Further, with the increase in the depth of focus, the occurrence of poor resolution was also significantly improved.

[Brief description of the drawings]

FIGS. 1A, 1B, and 1C are a cross-sectional view, a transmission light amplitude distribution diagram, and a light intensity diagram of a photomask according to an embodiment of the present invention, respectively.

FIGS. 2A, 2B, and 2C are a cross-sectional view of a conventional photomask, an amplitude distribution diagram of transmitted light, and a light intensity diagram, respectively.

FIG. 3 is a cross-sectional view of another embodiment of the present invention.

FIG. 4 is a cross-sectional view of another embodiment of the present invention.

FIG. 5 is a cross-sectional view of another embodiment of the present invention.

FIG. 6 is a cross-sectional view of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Cr film 3 Light transmission part 4 Translucent film 6 Thin Cr film 7 Coated glass film 8 Etching stopper 9 Transparent film

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03F 1/00-1/16

Claims (9)

(57) [Claims] 1. A translucent area having a transmittance of exposure light of 30% or less and an alignment mark portion or a detection window pattern.
A substrate having a light-shielding region, the first light having passed through the translucent region and the first light having passed through an opening provided in the translucent region having phases opposite to each other. A certain second
A hole pattern for an electrode wiring conductive hole is transferred to a thin film of a photosensitive material on a wafer by projecting the light through a lens. 2. The method according to claim 1, wherein the first and second lights are excimer laser light. 3. The method according to claim 1, wherein the translucent region is a single film provided on a glass substrate. 4. The method according to claim 1, wherein the translucent region is a multilayer film. 5. The method according to claim 1, wherein the opening is formed by etching a glass substrate.
The method for producing an electrode wiring conduction hole according to any one of the above. 6. A translucent area having a transmittance of exposure light of 30% or less and an alignment mark portion or a detection window pattern.
A substrate having a light-shielding region, the first light having passed through the translucent region and the first light having passed through an opening provided in the translucent region having phases opposite to each other. A certain second
A hole pattern for an electrode wiring conductive hole is transferred to a thin film of a photosensitive material on a wafer by projecting the light through a lens. 7. An area that is transparent to exposure light, a translucent area having a transmittance of 30% or less when the transmittance of the transparent area is 100%, and an alignment mark.
Having a light-shielding region in which a portion or a detection window pattern is formed, and transmitting light to a first substrate in which light transmitted through the transparent region and light transmitted through the translucent region are inverted from each other,
A method for manufacturing a semiconductor device, comprising a step of transferring a hole pattern for an electrode wiring conduction hole to a photosensitive thin film on a wafer by projecting through a lens. 8. A translucent area having a transmittance to exposure light of 30% or less, a transparent area provided in the translucent area, an alignment mark portion or a detection window pattern.
A light-shielding region formed, and transmitting light to a first substrate in which a phase of light transmitted through the transparent region is inverted with respect to a phase of light transmitted through the translucent region; Forming a hole pattern by projecting a hole pattern for an electrode wiring conduction hole formed on the second substrate through a lens onto a second substrate. 9. A step of forming a thin film of a photosensitive material on a first substrate, wherein the first region and the first region have a transmittance of 30% or less, where the transmittance of light is 100%. and a second region, place
A light-shielding region forming an alignment mark portion or a detection window pattern , wherein a phase of light transmitted through the first region is inverted from a phase of light transmitted through the second region. Irradiating a second substrate with light, projecting a hole pattern for an electrode wiring conduction hole through the lens on the first substrate using the first region and the second region; and Developing a substrate and forming a hole pattern.