JPH07230161A - Photomask for t-type gate electrode formation, its manufacture, and manufacture of semiconductor device provided with t-type gate electrode - Google Patents

Abstract

PURPOSE:To obtain a photomask for T-type gate electrode formation used in the manufacture of a semiconductor device provided with a T-type gate electrode. CONSTITUTION:Light shielding film 3 are formed on a glass substrate 1 for photomask symmetrically centering about the center part of the T-type gate electrode with a chrome, etc., in size (around 1mum on the mask) so as not to resolve a resist pattern. A shifter 2 is formed on the film so that the pattern edge of the shifter 2 can be located in the center of the light shielding film 3, and such structure that the light shielding film 3 on one side is covered with the shifter 2 is employed. T-type light intensity distribution 6 required for the formation of the T-type gate electrode can be obtained on a wafer for one time of exposure as exposure light transmitting the photomask 100 by using the photomask with such structure in a demagnification projection exposure method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a T-type gate electrode forming photomask, a method of manufacturing the same, and a method of manufacturing a semiconductor device having a T-type gate electrode, and more particularly, a T-shaped cross section used for manufacturing a compound semiconductor device. The present invention relates to a structure of a photomask capable of forming a mold pattern, a manufacturing method thereof, and a manufacturing method of a semiconductor device using the photomask.

[0002]

2. Description of the Related Art In a field effect transistor of a compound semiconductor, it is possible to improve the performance of the transistor by shortening the gate length. However, in order to compensate for the increase in the gate resistance due to the reduction in the gate cross-sectional area due to the shortening of the gate length, it is necessary to provide a T-shaped gate electrode having a T-shaped cross section as shown in FIG. FIG. 9 is a cross-sectional view showing a conventional T-type gate pattern forming method for manufacturing a semiconductor device having a T-type gate electrode. In FIG. 9, 72 is a semiconductor substrate, and 84 is a lower layer electron beam resist. , 85 is an upper layer photoresist, 10 is a photomask for forming an upper layer resist pattern formed by forming a light shielding pattern 3 on the transparent plate 1, 92 is an upper layer resist exposure light, 93 is a lower layer resist exposure electron beam, and 74 is a recess The groove 11 is a T-type gate electrode having a central portion 11b and an upper portion 11a.

A method of forming the T-type gate electrode will be described below with reference to FIG. First, as shown in FIG. 9A, an active layer (not shown) is formed by an epitaxial growth method or the like.
The electron beam resist 84 on which the
A film having a thickness of 00 angstrom is formed, and a photoresist 85 is formed on the electron beam resist 84 by 5000 to 2
It is formed with a film thickness of 0000 angstrom. Then, by using the upper-layer resist pattern forming photomask 10 and a reduction projection exposure device (not shown), T
The upper electrode portion pattern of the mold gate electrode is exposed.

Next, as shown in FIG. 9B, the upper layer photoresist 85 is developed to remove the unexposed region of the upper layer photoresist 85, and the upper electrode portion resist pattern 86 of the T-type gate electrode. To get Then, the T-shaped gate lower electrode pattern region is irradiated with the electron beam 93 on the electron beam resist 84 to expose the lower electrode pattern.

Then, as shown in FIG. 9C, the electron beam resist 84 is developed to remove the exposed region of the electron beam resist 84, and the lower electrode portion resist pattern 87 of the T-type gate electrode is formed. To get

Then, the active layer 73 is wet-etched using the lower electrode resist pattern 87 as a mask to form a recess groove 74 in a part of the surface of the semiconductor substrate 72 (active layer). Then, after depositing a metal for the gate electrode on the entire surface, lift-off is performed, as shown in FIG.
The T-type gate electrode 11 shown in is formed.

[0007]

As a conventional mask pattern for forming a T-type gate electrode, a lower layer resist (electron beam resist) 84 and an upper layer resist (photoresist) 85 are used, and these are each used as an electron beam. Since it is formed by a beam exposure method and a two-layer resist process of exposing by a normal exposure method, it is necessary to pattern the resist twice, which complicates the process, and particularly a pattern having a high pattern density or a T-type gate. There is a problem in that throughput is low and mass production is difficult in a pattern in which an overlay accuracy of the upper electrode resist pattern and the lower electrode resist pattern of the electrode is required.

Further, since it is necessary to perform patterning of the resist twice, the process is complicated, so that the process of forming the T-type gate electrode is complicated, and the semiconductor device having the T-type gate electrode can be manufactured efficiently in a short time. There is a problem that it is difficult to form well.

The present invention has been made in order to solve the above problems, and it is possible to form a resist pattern required for forming a T-type gate electrode with good uniformity and in a short time. It is an object to provide a photomask for forming a gate electrode and a method for manufacturing the same. Another object of the present invention is to provide a method of manufacturing a semiconductor device having a T-type gate, which can form the T-type gate electrode with good uniformity in a short time.

[0010]

A photomask for forming a T-type gate electrode according to the present invention is a photomask for forming a T-type gate electrode used for forming a T-type gate electrode on a semiconductor substrate. On a transparent substrate,
A pair of light-shielding films, each having a size that does not allow the resist to be resolved, are formed at symmetrical positions with respect to a position corresponding to the center of the T-shaped gate electrode, and the photomask is formed in a photolithography process. A shifter for inverting the phase of the exposure light when the exposure light is transmitted is formed so that the pattern edge is located at the center of the pair of light shielding films and covers one of the light shielding films. In the light intensity distribution of the exposure light obtained on the wafer by passing the exposure light through the photomask, a very small dark portion corresponding to the central portion of the T-shaped gate electrode and the T
Has a T-shaped light intensity distribution having a minute dark portion corresponding to the upper part of the gate electrode, and the T-shaped light intensity distribution is
It is obtained on the wafer by one exposure.

Further, according to the present invention, in the above T-type gate electrode forming photomask, a shifter portion for inverting the phase of the exposure light is formed by engraving a glass substrate by a required thickness.

A T-type gate electrode forming photomask according to the present invention is a T-type gate electrode forming photomask used for forming a T-type gate electrode on a semiconductor substrate, wherein the T-type gate electrode forming photomask is formed on a photomask transparent substrate. Provided,
It corresponds to the upper portion of the T-shaped gate electrode, which is symmetrical with respect to the light-transmitting opening of the pattern corresponding to the central portion of the T-shaped gate electrode, and symmetrical with respect to the light-transmitting opening pattern on the transparent substrate for the photomask. Of the exposure light obtained on the wafer by exposing the exposure light through the photomask. The light intensity distribution is an inverted T-shaped light intensity distribution having a very small bright portion corresponding to the central portion of the gate electrode and a minute bright portion corresponding to the upper portion of the T-shaped gate. The V-shaped light intensity distribution is obtained on the wafer by one exposure.

Further, according to the present invention, in the photomask for forming a T-type gate electrode, the semi-shielding film portion is provided on both sides of the translucent opening pattern on the transparent substrate for the photomask. Including the position where the light shielding film is to be formed, a light shielding film having a required film thickness, which will be the light shielding film portion on the outside, is formed, and a portion where the semi-light shielding film portion on the inside of the formed light shielding film is to be formed is predetermined. It is formed by etching to a film thickness.

Further, according to the present invention, in the photomask for forming a T-type gate electrode, the light-shielding film portion is provided on both sides of the light-transmitting opening pattern on the transparent substrate for the photomask. It is formed by forming a light-shielding film at a position to be formed and then ion-implanting the semi-light-shielding film portion on the transparent substrate for the photomask at a position to be formed.

Further, according to the present invention, in the photomask for forming a T-type gate electrode, the semi-light-shielding film portion is formed by a repeating pattern of light-shielding films having a size that does not resolve a resist film. However, the light shielding film is formed on the entire surface.

A method of manufacturing a T-type gate electrode forming photomask according to the present invention is a method of manufacturing a T-type gate electrode forming photomask for forming a T-type gate electrode on a semiconductor substrate. A light-shielding film is formed on one surface of the transparent substrate for use in the patterning, and is patterned so that the resist is not resolved at symmetrical positions about the position corresponding to the center of the T-shaped gate electrode. A step of forming a pair of light-shielding films having a size, and a shifter for inverting the phase of the exposure light when the exposure light is transmitted through the photomask, on which the light-shielding film is formed on the transparent substrate for the photomask. A step of forming a material on the entire surface and then patterning the material so that the pattern edge is located at the center of the pair of light-shielding films and covers either one of the light-shielding films. In the photolithography process, the light intensity distribution of the exposure light obtained by transmitting the exposure light through the photomask on the wafer has a very small dark portion corresponding to the central portion of the T-shaped gate electrode and the T-shaped gate electrode. A photomask for forming a T-shaped gate electrode having a T-shaped light intensity distribution having a minute dark portion corresponding to the upper electrode is manufactured.

A method of manufacturing a T-type gate electrode forming photomask according to the present invention is a method of manufacturing a T-type gate electrode forming photomask used for forming a T-type gate electrode on a semiconductor substrate. Forming a light-shielding film on one surface of the mask transparent substrate; forming an opening in the light-shielding film at a position corresponding to the central portion of the T-shaped gate electrode; and forming a light-shielding film on the photomask transparent substrate. A portion of the light-shielding film, which is symmetrical with respect to the opening pattern and which corresponds to the upper portion of the T-shaped gate electrode, is etched to a thickness of about half to form a semi-light-shielding film. A step of leaving it as a light-shielding film as it is, the light intensity distribution of the exposure light obtained by transmitting the exposure light through the photomask on the wafer is a very small bright portion corresponding to a portion having a gate length, and a T-shaped light portion. It is intended to produce an inverted T-shaped T-shaped gate electrode forming a photomask such that the light intensity distribution having a small bright portion corresponding to the portion to be the over preparative upper electrode.

A method of manufacturing a T-type gate electrode forming photomask according to the present invention is a method of manufacturing a T-type gate electrode forming photomask used for forming a T-type gate electrode on a semiconductor substrate. A step of forming a light shielding film on one surface of a transparent substrate for a mask, an opening including a position of the light shielding film corresponding to a central portion of the T-shaped gate electrode, and a position corresponding to an upper portion of the T-shaped gate electrode. And a step of forming a pattern of the opening pattern on the transparent substrate for the photomask except for a position corresponding to the central portion of the T-shaped gate electrode.
A step of implanting ions into a portion corresponding to the upper portion of the T-shaped gate electrode to form a semi-light-shielding portion, and the exposure light is transmitted through the photomask to obtain a light intensity distribution of the exposure light on a wafer. A T-shaped light intensity distribution having an inverted T-shaped light intensity distribution having a very small bright portion corresponding to the central portion of the T-shaped gate electrode and a minute bright portion corresponding to the upper portion of the T-shaped gate electrode. A photomask for forming a gate electrode is manufactured.

Further, according to the present invention, in a method for manufacturing a T-type gate electrode forming photomask used for forming a T-type gate electrode on a semiconductor substrate, a light-shielding film is formed on one surface of a photomask transparent substrate. And the position of the light shielding film corresponding to the central portion of the T-shaped gate electrode,
All of them are openings, and a position corresponding to the upper part of the T-shaped gate electrode on the outer side thereof is a repeating pattern of the light shielding film having a size that the resist film is not resolved by the light shielding film and the outer side thereof. A step of forming an opening so that the light-shielding film is formed as it is, and the light intensity distribution of the exposure light obtained on the wafer by passing the exposure light through the photomask is the center of the T-shaped gate electrode. A photomask for forming a T-type gate electrode having an inverted T-shaped light intensity distribution having a very small bright portion corresponding to a portion to be a portion and a minute bright portion corresponding to a portion to be an upper portion of a T-shaped gate electrode. It is manufactured.

Further, according to the present invention, a method of manufacturing a semiconductor device having a T-type gate electrode using the above-mentioned photomask for forming a T-type gate electrode is applied to a semiconductor substrate by applying a negative type or image reversal type photoresist. The resist film is exposed by photolithography using a T-shaped gate electrode forming photomask capable of obtaining the above T-shaped light intensity distribution as the light intensity distribution of the exposure light obtained on the wafer And a step of developing the exposed resist film to form a resist pattern having an opening having a T-shaped cross section, and performing wet etching using the resist pattern as a mask to form a recess groove on the surface of the semiconductor substrate. And a gate metal is deposited using the resist pattern as a mask to form a gate electrode in the recess groove. It is intended to include a step of removing unnecessary metal by lift-off method.

A method of manufacturing a semiconductor device having a T-type gate electrode using the photomask for forming a T-type gate electrode according to the present invention comprises a step of coating and forming a positive photoresist on a semiconductor substrate, A step of exposing the resist film by photolithography using a photomask for forming a T-shaped gate electrode capable of obtaining the above-mentioned inverted T-shaped light intensity distribution as the light intensity distribution of the exposure light obtained on the wafer; Developing the exposed resist film to form a resist pattern having an opening having a T-shaped cross section, and performing wet etching using the resist pattern as a mask to form a recess groove on the surface of the semiconductor substrate. , Gate metal is vapor-deposited by using the resist pattern as a mask to form a gate electrode in the recess groove, which is unnecessary by the lift-off method. It is intended to include removing the genus.

[0022]

According to the present invention, a T-type gate electrode forming photomask used for forming a T-type gate electrode on a semiconductor substrate corresponds to the central portion of the T-type gate electrode on the photomask transparent substrate. A pair of light-shielding films, each having a size that does not allow the resist to be resolved, are formed at symmetrical positions with respect to the position where the exposure light is transmitted through the photomask in the photolithography process. A shifter for inverting the phase is formed so that the pattern edge is located at the center of the pair of light shielding films and covers either one of the light shielding films, and the exposure light is transmitted through the photomask in the photolithography process. The intensity distribution of the exposure light obtained on the wafer is
Since the T-shaped light intensity distribution has a very small dark portion corresponding to the central portion of the T-shaped gate electrode and a minute dark portion corresponding to the upper portion of the T-shaped gate electrode, the central portion of the T-shaped gate electrode is centered. It is possible to obtain exposure light having a T-shaped light intensity distribution, and in the case of using a negative or image reversal resist, a T-shaped light intensity distribution necessary for forming a T-shaped gate electrode in one exposure. Can be obtained on the wafer to obtain a resist pattern having a T-shaped opening, and since there is no need to perform overlay exposure as in the conventional technique, the throughput is high and the T-shaped gate electrode is highly accurate. Can be formed.

Further, in the present invention, in the T-type gate electrode forming photomask, the shifter for inverting the phase of the exposure light is formed by digging the photomask transparent substrate by a required thickness. Can
Moreover, at this time, even if dust adheres to the photomask, it can be removed by washing with a brush or the like, and the shifter material is not peeled off, and it is not necessary to correct it.

Further, according to the present invention, in a T-type gate electrode forming photomask used for forming a T-type gate electrode on a semiconductor substrate, the T-type gate electrode is provided on the transparent substrate for the photomask. The transparent opening having a pattern corresponding to the central portion and a portion corresponding to the upper portion of the T-shaped gate electrode, which is symmetrical with respect to the transparent opening pattern on the transparent substrate for the photomask, are formed. A semi-light-shielding film portion and light-shielding film portions disposed on both outer sides of the semi-light-shielding film portion are provided, and the light intensity distribution of the exposure light obtained by transmitting the exposure light through the photomask on the wafer is The inverted T-shaped light intensity distribution has an extremely small bright portion corresponding to a long portion and a minute bright portion corresponding to a portion to be a T-shaped gate upper electrode, and the inverted T-shaped light intensity distribution is By one exposure It is so arranged obtained on the wafer, overlapping is not necessary to exposure as in the prior art, high throughput, it is possible to form a highly accurate T-shaped gate electrode.

Further, in the present invention, the semi-shielding film portion in the photomask for forming the T-type gate electrode is formed on both sides of the translucent opening pattern on the photomask transparent substrate. A light-shielding film having a required film thickness, which will be the light-shielding film portion on the outside including the position to be formed, is formed, and a portion inside the formed light-shielding film where the semi-light-shielding film portion is to be formed is a predetermined film. It can be formed by thick etching.

Further, in the present invention, the semi-shielding film portion in the photomask for forming the T-type gate electrode is formed on both sides of the translucent opening pattern on the transparent substrate for the photomask. It can be formed by forming a light-shielding film at a position to be formed and then ion-implanting the semi-light-shielding film portion on the photomask transparent substrate at a position to be formed.

Further, in this way, the light shielding film portion and the semi-light shielding film portion are formed on the transparent substrate for the photomask in a bilaterally symmetrical structure with the gate electrode portion as the center, and the positional relationship between the light shielding film portion and the semi-light shielding film portion. When the semi-light-shielding film portion is arranged on both sides of the central portion of the gate electrode and the light-shielding film portion is located just outside thereof, a positive resist is used to form the T-shaped gate electrode in one exposure. A necessary inverted T-shaped light intensity distribution can be obtained on the wafer to obtain a resist pattern having a T-shaped opening, which eliminates the need for overlay exposure as in the prior art. Therefore, a T-type gate electrode with high throughput and high accuracy can be formed.

Further, in the present invention, the semi-light-shielding film portion of the T-type gate electrode forming photomask is formed by a repeating pattern of the light-shielding film having a size that does not resolve the resist film, and the light-shielding film portion is formed. Since the light-shielding film is formed on the entire surface, the semi-light-shielding film portion can be obtained by the repeating pattern of the light-shielding film,
Moreover, at this time, an inverse T-shaped light intensity distribution necessary for forming the T-shaped gate electrode can be obtained on the wafer by one exposure, and a resist pattern having an opening shape of T-shaped can be obtained.
As a result, it is not necessary to perform overlay exposure as in the prior art, so that it is possible to form a T-type gate electrode with high throughput and high accuracy.

Further, in the method of manufacturing a semiconductor device having a T-type gate electrode according to the present invention, a step of coating and forming a negative type or image reversal type photoresist on a semiconductor substrate, and an exposure light obtained on the wafer. The above T-shaped light intensity distribution can be obtained as the light intensity distribution of
A step of exposing the resist film by photolithography using the T-type gate electrode forming photomask; a step of developing the exposed resist film to form a resist pattern having a T-shaped opening; Wet etching is performed using the resist pattern as a mask to form a recess groove on the semiconductor substrate surface, and a gate metal is vapor-deposited using the resist pattern as a mask to form a gate electrode in the recess groove by a lift-off method. Since the step of removing the unnecessary metal is included, the above-mentioned T-shaped gate electrode forming photomask capable of obtaining the light intensity distribution of the T-shaped exposure light on the wafer is used. An image reversal type photoresist can be used to manufacture a field effect transistor having a T-type gate electrode.

Further, in the method of manufacturing a semiconductor device having a T-type gate electrode according to the present invention, the step of coating and forming a positive photoresist on the semiconductor substrate and the light intensity distribution of the exposure light obtained on the wafer are A step of exposing the resist film by photolithography using the T-shaped gate electrode forming photomask having the above-mentioned inverted T-shaped light intensity distribution, and developing the exposed resist film to form a T-type A step of forming a resist pattern having an opening, a step of performing wet etching with the resist pattern as a mask to form a recess groove on the surface of the semiconductor substrate, and a step of depositing a gate metal with the resist pattern as a mask to form the recess Since the step of forming a gate electrode in the groove and removing unnecessary metal by a lift-off method is included, A field effect transistor having a T-type gate electrode is manufactured by using a T-type gate electrode forming photomask capable of obtaining a light intensity distribution of an inverted T-shaped exposure light on the wafer and using a positive type photoresist. be able to.

[0031]

EXAMPLES Example 1 FIG. 1 is a sectional view showing the structure of a photomask for forming a T-type gate electrode according to the first embodiment of the present invention, the amplitude distribution of exposure light on the mask when using the photomask, and the exposure light on the wafer. FIG. 3 is a diagram showing an amplitude distribution of, and a light intensity distribution of exposure light on a wafer.

In FIG. 1 (a), 1 is a glass substrate for a photomask, 3 is a light-shielding film made of a pair of Cr, which is symmetrically arranged around the center of the T-shaped gate electrode to be formed. , Which has a width of 0.2-0.4 μm on the wafer such that the resist on the wafer does not resolve, 1
It has a thickness of less than 000 angstroms.
2 is formed on the glass substrate 1 for the photomask,
This is a shifter made of SiO2 or the like having a thickness of 4000 angstroms for inverting the phase of exposure light. This shifter has a pattern at a position corresponding to the center of the pair of light shielding films 3, that is, the center of the T-shaped gate electrode to be formed. It is formed so that the edge is arranged and covers either one of the light shielding films 3. Here, the film thickness of the shifter material is λ / 2 (n-), where λ is the wavelength of the exposure light and n is the refractive index of the shifter material (SiO2) in order to invert the phase of the exposure light.
The thickness is represented by 1). In the first embodiment, the T-type gate electrode forming photomask 1 is formed by the photomask glass substrate 1, the pair of light-shielding films 3, and the shifter 2.
00 is formed.

In FIGS. 1 (b), (c) and (d), 4 is the photomask 10 of the exposure light transmitted through the photomask 100.
Amplitude distribution on 0, 5 indicates the amplitude distribution of the exposure light on the semiconductor wafer, and 6 indicates the light intensity distribution of the exposure light on the wafer.

FIG. 2 is a sectional view showing a method of manufacturing the T-type gate electrode forming photomask 100. In the figure, the same reference numerals as those in FIG. 1 indicate the same or corresponding portions. 13 is Cr formed on the entire surface of the glass substrate 1.
A film, 14 is a resist mask formed on the Cr film 13 for forming the light shielding film 3 from the Cr film 13 by etching, 12 is a shifter material formed on the entire surface of the glass substrate 1, and 15 is the shifter material 12 A resist formed for forming the shifter 2 on the top.

Next, a method for manufacturing the T-type gate electrode forming photomask 100 of the first embodiment will be described with reference to FIG. First, as shown in FIG. 2 (a), a Cr film 13 is formed on the entire surface of the glass substrate 1 by a sputtering method, a resist is applied on the Cr film 13, and the resist is patterned by electron beam exposure or the like to form a resist mask. 14 (FIG. 2)
(b)).

Next, by using the resist mask 14 as a mask, the Cr film 13 is dry-etched to form a light-shielding film 3 on the photomask glass substrate 1. At this time, the size of the light shielding film 3 is such that the resist pattern on the wafer is not resolved by the exposure light shielded by the light, that is, the width of each light shielding film 3 is 0.2 on the wafer. A portion corresponding to the center portion of the gate electrode that constitutes the gate length of the T-type gate electrode to be formed (the size is about 0.4 μm and the distance between the two is about 1 μm on the wafer). In the figure, the mask is formed symmetrically with respect to the center of the mask (FIG. 2 (c)).

Thereafter, the liquid glass is spin-coated, or deposited or sputtered by a CVD apparatus, so that the shifter material 12 made of SiO 2 is attached to the entire surface of the glass substrate 1 on which the light-shielding film 3 is formed. After this (FIG. 2 (d)), a resist is applied to the entire surface of the shifter material 12 and then patterned by electron beam exposure or the like to form a resist mask 15 (FIG. 2).
(e)), using this resist 15 as a mask, the shifter material 12
By removing the unnecessary portion of the above by dry etching, the shifter 2 is formed (FIG. 2 (f)). At this time, the shifter 2 is arranged and formed in the center of the pair of light-shielding films 3 so that the pattern edges thereof come and one of the light-shielding films 3 is covered with the shifter 2. Obtain the mask 100.

Next, the principle of resist patterning when exposure for forming a T-type gate electrode is performed using the T-type gate electrode forming photomask 100 of the first embodiment will be described.

When the T-type gate electrode forming photomask 100 having the structure shown in FIG. 1A is arranged so that the surface having the light-shielding film 3 faces the wafer side and used in the reduction projection exposure method, The amplitude distribution of the exposure light transmitted through the photomask 100 on the mask becomes the amplitude distribution 4 shown in FIG. 1B because the phase of the exposure light transmitted through the shifter material is inverted.
However, the exposure light on the actual wafer is affected by the diffraction phenomenon, and a part of the exposure light transmitted through the photomask 100 also wraps around to the portion shielded by the light shielding portion 3 shown in FIG. The amplitude distribution 5 is as shown in FIG. Here, since the light intensity distribution is represented by the square of the amplitude distribution, in this case, a T-shaped light intensity distribution 6 as shown in FIG. 1D is obtained on the wafer. Therefore, when a single layer negative resist formed on the wafer is exposed by the photomask 100, the negative resist on the wafer is exposed according to the intensity distribution. By removing the unexposed portion of the negative resist exposed by this photomask, it becomes possible to form a resist pattern in which the cross-sectional shape of the removed portion is T-shaped.

In the conventional method of manufacturing a semiconductor device having a T-type gate electrode shown in FIG. 9, in order to form the T-type gate electrode, the upper electrode portion 11a of the T-type gate electrode 11 is formed.
And a first resist 86 having an opening corresponding to, and a gate electrode central portion (lower electrode portion) 11 of the T-type gate electrode 11.
a second resist 87 having an opening corresponding to b,
Although it is necessary to form a two-layer resist, if the photomask 100 of this embodiment is used, a single-layer negative resist or an image reversal resist is exposed once to obtain the above T-shaped light. The intensity distribution can be obtained, and the patterning required for forming the T-type gate electrode can be performed.

In the photomask 100 for forming the T-type gate electrode according to the first embodiment as described above, the resist is resolved on the glass substrate for photomask 1 symmetrically with respect to the center of the T-type gate electrode. And a pair of light-shielding films 3 arranged in such a size that the pattern edge is located at the center of the pair of light-shielding films, and the phase of the exposure light is inverted so as to cover one of the light-shielding films. And a shifter 2 for allowing the exposure light to pass through the photomask in the photolithography step, the light intensity distribution of the exposure light obtained on the wafer is
A T-shaped light intensity distribution having an extremely small dark portion corresponding to the central portion of the T-shaped gate electrode and a minute dark portion corresponding to the upper electrode of the T-shaped gate electrode is obtained, and a single-layer negative resist or image reversal resist is obtained. On the other hand, the exposure necessary for forming the gate pattern can be performed at one time, and a gate pattern having good uniformity, that is, a uniform removal degree of the resist pattern can be easily formed in a short time. In addition, the T-type gate electrode forming photomask 100 can be manufactured by the simple steps as described above.

Although Cr is used as the material of the light-shielding film in the present embodiment, CrO or MoSi may be used as the material of the light-shielding film, and the same effect as that of the above-mentioned embodiment is obtained. Play.

Example 2 FIG. 3 is a sectional view showing the structure of a photomask according to the second embodiment of the present invention. In FIG. 3, the same reference numerals as those in FIG. 1 indicate the same or corresponding portions, and 21 indicates on the glass substrate 1. Formed shifter part, 30
Reference numeral 0 is a photomask for forming a T-type gate electrode according to the second embodiment.

In the photomask 100 shown in the first embodiment (FIG. 1 (a)), the shifter 2 is disposed on the glass substrate 1 after the formation of the light-shielding film 3 and the portion for inverting the phase of the exposure light. However, in the second embodiment,
Instead of arranging this shifter 2, as shown in FIG.
A region of the glass substrate 1 where the shifter is to be formed is dry-etched using a resist (not shown) to a predetermined depth, for example, 4000 angstroms, to form the phase shifter portion 21. It is the one. By doing so, an exposure light amplitude distribution similar to the exposure light amplitude distribution 4 obtained on the mask of Example 1 shown in FIG. 1B can be obtained on the T-shaped gate electrode. The photomask 300 for formation can be obtained. Here, the depth to be dug is such that the phase can be inverted, λ / 2 (n, as described in the first embodiment.
The depth is represented by -1).

In the second embodiment, as in the first embodiment, the light intensity distribution of the exposure light obtained on the wafer by passing the exposure light through the photomask in the photolithography process is T-shaped. Since the light intensity distribution of the mold becomes, the exposure required when forming a gate pattern for a single layer negative resist or image reversal resist can be performed at one time, and a gate pattern with good uniformity can be easily formed in a short time. You can get the effect that you can. In addition, even if the surface of the photomask, that is, the surface of the glass plate is cleaned by applying a physical force with a brush or the like by digging the glass plate and providing the shifter portion 21, the first embodiment is performed. Unlike the photomask of the example, the shifter material does not come off, and even if dust or dirt adheres to the surface, it is possible to easily wash and remove it.

Example 3 The first and second embodiments are the negative resist or the image reversal resist 8
Photomasks 100 and 30 for forming a T-type gate electrode, which can be used when a T-type gate electrode is formed by using
The third embodiment of the present invention relates to a photomask that can be used when a T-type gate electrode is formed using a positive resist. The principle will be described.

FIG. 4 is a sectional view showing the structure of a T-type gate electrode forming photomask according to the third embodiment of the present invention (FIG. 4).
(a)), and the amplitude distribution of the exposure light on the mask when using this (Fig. 4 (b)), the amplitude distribution of the exposure light on the wafer (Fig. 4 (c)), It is a figure (FIG.4 (d)) which shows the light intensity distribution of exposure light.

In FIG. 4, as in FIG. 1, 1 is a glass substrate for a photomask. Further, 3 is a light-shielding film made of Cr, or CrO, MoSi that blocks transmission of exposure light on the glass substrate 1 for the photomask.
An opening 32 (0.2 to 0.4 μm in width dimension on the wafer) is provided at a position corresponding to the gate electrode central portion (10a in FIG. 7) of the T-shaped gate electrode to be formed using this photomask, A semi-light-shielding film portion 31 (each having a width dimension of 0.
3 to 2.0 μm), and further, on both outer sides thereof, a light shielding film portion 30 having a thickness of about 1000 Å which is a thickness at the time of initial formation. And about 5 above
Semi-light-shielding film portion 3 formed to a film thickness of 00 angstrom
No. 1 has a transmittance of exposure light of about 50% due to this film thickness, but the film thickness of the semi-light-shielding film portion 31 is T
The transmittance can be adjusted in the range of 20 to 80% according to the thickness of the upper electrode portion of the mold gate electrode. Then, the above photomask glass substrate 1 and the light shielding film 3
Thus, the photomask 400 of the third embodiment is formed.

In FIGS. 4B, 4C, and 4D, 41 is the amplitude distribution of the exposure light on the photomask 400, and 51 is
Shows the amplitude distribution of the exposure light on the semiconductor wafer after passing through the photomask 400, and 61 shows the light intensity distribution of the exposure light on the wafer.

In manufacturing the T-type gate electrode forming photomask 400 of the third embodiment, first, the light-shielding film 3 made of Cr or the like is sputtered on the glass substrate 1 for the photomask to a thickness of about 1000 Å. Then, using a resist having an opening size corresponding to the central electrode portion (10a in FIG. 7) of the T-type gate electrode to be formed in the center of the light shielding film 3, RIE (reactive ion etc.
The opening 32 reaching the glass substrate 1 is formed by etching by hing), and thereafter, an upper electrode portion of the T-shaped gate electrode to be formed which is larger than this (10b in FIG. 7).
By using a resist having an opening size corresponding to the above, the light-shielding film 3 is also etched by RIE to about half its film thickness to form a semi-light-shielding film portion 31 having a thickness of about 500 angstroms. Photo mask 4
00 can be obtained.

Here, although the above-mentioned Cr and CrO are slightly different from each other in the degree of light shielding against light, a CrO film is used as the light-shielding film portion 3.
In addition, a Cr film may be used for the semi-light-shielding film portion 31. In this case, the light-shielding film portion 30 made of Cr has a film thickness of about 1000 angstroms as in the above case.
The film thickness of the semi-light-shielding film part 31 made of rO may be adjusted within the range in which the transmittance is 20 to 80% according to the thickness of the upper electrode part of the T-type gate electrode to be formed.

Such a light shielding film portion 30 and a semi-light shielding film portion 31
In the manufacture of a T-type gate electrode forming photomask using different materials, a light-shielding film 3 made of Cr is formed on the photomask glass substrate 1 by a sputtering method to a thickness of about 1000 Å, and then the At the center of the light shielding film, the upper electrode portion of the T-shaped gate electrode to be formed (see FIG.
10b), a resist having an opening size is used to form an opening by etching by RIE, and the remaining portion is used as a light-shielding film portion 30. Then, a film made of CrO is formed in the formed opening (see FIG. (Not shown) is formed to a required film thickness, and a resist having an opening size corresponding to the central electrode portion (10a in FIG. 7) of the T-type gate electrode to be formed is used at the center thereof and RIE is performed to remove the CrO from the CrO. The photomask 400 can be obtained by etching the resulting light-shielding film to form the opening 32 and leaving the remaining portion as the semi-light-shielding film portion 31.

When the photomask 400 of the third embodiment having the structure shown in FIG. 4 (a) is used in the reduction projection exposure method, the exposure light transmitted through the photomask 400 on the mask is as shown in FIG.
The amplitude distribution 41 shown in (b) is obtained. However, the exposure light on the actual wafer is affected by the diffraction phenomenon,
Also, it wraps around to the portion of the semi-light-shielding film 31 and has an amplitude distribution 51 as shown in FIG. The light intensity distribution has an amplitude distribution of 2
In this case, the inverted T-shaped light intensity distribution 61 as shown in FIG. 6D is obtained on the wafer because it is represented by the raised power. Therefore, when the positive resist on the wafer is exposed by the photomask 400, the positive resist on the wafer is exposed according to the light intensity distribution, and when the exposed portion of the exposed positive resist is removed, the removed portion of the removed positive resist is removed. It becomes possible to form a resist pattern having a T-shaped cross section. Therefore, with this photomask 400, the light intensity distribution required for forming the T-type gate electrode on the positive resist can be obtained by one exposure.

As described above, in the T-type gate electrode forming photomask 400 according to the third embodiment, the opening 32 formed in the center of the photomask glass substrate and the left and right sides of the opening pattern centered on the opening pattern. Since the light shielding film 3 has the semi-shielding film portions 31 formed symmetrically and the light shielding film portions 30 formed on both outer sides of the semi-shielding film portion, the photomask is exposed to the exposure light. The light intensity distribution of the exposure light obtained on the wafer by transmission is of an inverted T-shape having an extremely small bright portion corresponding to the central portion of the gate electrode and a small bright portion corresponding to the T-shaped gate upper electrode portion. Since the light intensity distribution is obtained, the exposure required when forming a gate pattern for a single-layer positive resist can be performed at one time, and a gate pattern with good uniformity can be easily formed in a short time. Can Effect can be obtained. Moreover, the T-type gate electrode forming photomask 400 can be manufactured by the simpler process as described above.

Example 4 FIG. 5 is a sectional view showing the structure of a T-type gate electrode forming photomask according to the fourth embodiment of the present invention. In FIG. 5, 1, 3 and 30 are the same as those in the third embodiment, Reference numeral 33 denotes a glass substrate, a light shielding film, and a light shielding film portion, respectively, and 33 denotes a semi-light shielding portion formed by implanting gallium ions or the like on the surface of the glass substrate 1. That is, the photomask 500 according to the fourth embodiment is shown in FIG.
In place of the semi-light-shielding film portion 31 of the third embodiment shown in FIG. 3, gallium ions with a predetermined concentration are added to the glass substrate 1 for a region corresponding to the semi-light-shielding film portion 31 of the photomask glass substrate 1.
The semi-light-shielding portion 33 is formed by driving near the surface.

When gallium ions are implanted into the glass substrate, the transmittance of the exposure light is reduced according to the concentration, and the region becomes a semi-shielded region. Therefore, the concentration of gallium ions implanted is changed as in the fourth embodiment. By adjusting the same as in the photomask 400 of the third embodiment, as shown in FIG.
It is possible to obtain the photomask 500 that produces the amplitude distribution and the light intensity distribution of the exposure light as shown in (c) and (d).

As described above, in the T-type gate electrode forming photomask 500 according to the fourth embodiment, the semi-light-shielding portion is formed on the glass substrate for the photomask symmetrically by ion implantation in the left and right with the central portion as the center. 33 and a light shielding film portion 30 arranged and formed on both outer sides of the semi-light shielding portion, the light intensity of the exposure light obtained on the wafer by passing the exposure light through the photomask 500. Distribution is
This results in an inverted T-shaped light intensity distribution having a very small bright portion corresponding to the central portion of the gate electrode and a minute bright portion corresponding to the T-shaped gate upper electrode portion, and a gate is applied to a single-layer positive resist. The exposure required when forming the pattern can be performed at one time, and the effect that the gate pattern with good uniformity can be easily formed in a short time is obtained.

Example 5 FIG. 6 is a diagram showing the structure of a T-type gate electrode forming photomask according to the fifth embodiment of the present invention (FIG. 6A), and a wafer on which exposure is performed using the photomask. It is a figure (FIG.6 (b)) which shows the light intensity distribution of the exposure light in. In the figure, 600 is a T-type gate electrode forming photomask according to the fifth embodiment, and 50 is a thickness of about 10 formed on the photomask glass substrate 1.
A light-shielding film made of a Cr film of 00 Å,
This has an opening 51, which is about 0.3 to 0.4 μm in resolution of the resist film on the wafer, centered on the position where the central electrode portion (10a in FIG. 7) of the gate electrode is to be formed. A pattern having an interval such that the resist film is not resolved, that is, a width of 0.1 to 0.3 μm on the wafer and 0 on the wafer in a region corresponding to the gate upper electrode portion (10b in FIG. 7) in the outer region. The pattern has a semi-light-shielding portion 52 symmetrically provided with a pattern having an interval of 1 to 0.3 μm as a repetitive pattern, and a region outside thereof has a light-shielding portion, and is formed so as to cover the entire surface thereof. It has a light shielding film portion 53.

Next, in the manufacture of the photomask 600 of the fifth embodiment, first, a film of Cr, CrO, MoSi or the like is formed on the entire surface of the photomask glass substrate 1 by a sputtering method or the like, and then the Cr film is formed. By applying a resist on the surface of the resist, patterning the resist into the same pattern as the pattern of the Cr light-shielding film 50 to be formed, and then dry etching the film of Cr or the like using the patterned resist as a mask. The photomask 600 can be obtained.

Next, the principle of patterning the resist when forming the T-type gate electrode using the photomask 600 of the fifth embodiment will be described. When the photomask 600 of this embodiment is irradiated with light, a distribution 62 as shown in FIG. 6B is obtained as the light intensity distribution on the wafer. This light intensity distribution is the same as the light intensity distribution obtained by the photomask 500 of the fourth embodiment, and by performing exposure using this photomask 600, the cross-sectional shape similar to that of the fourth embodiment is obtained. Can form a T-shaped resist pattern.

In the photomask 600 of the fifth embodiment, the Cr film formed on the glass substrate 1 can be formed by patterning the Cr film once, which is different from the first to fourth embodiments. The number of steps for forming the photomask is reduced, and the steps can be shortened.

As described above, in the T-type gate electrode forming photomask 600 according to the fifth embodiment, the opening 51 having a width capable of resolving the resist formed at the center of the photomask glass substrate 1 is formed. A semi-light-shielding portion 52 formed of a repetitive pattern having a size that does not resolve a resist symmetrically formed on the left and right of the opening and a light-shielding portion 53 formed on both outer sides of the semi-light-shielding portion. Have C
Since it has a structure including the r light shielding film 50, the light intensity distribution of the exposure light obtained on the wafer by transmitting the exposure light through the photomask has an extremely small bright portion corresponding to the central portion of the gate electrode, The inverted T-shaped light intensity distribution has a minute bright portion corresponding to the T-shaped gate upper electrode portion. Therefore, the exposure necessary for forming a gate pattern for a single-layer positive resist must be performed at one time. Therefore, a gate pattern having good uniformity can be easily formed in a short time. Moreover, the manufacturing process can be further shortened as described above.

Example 6 FIG. 7 is a sectional view showing a method for manufacturing a semiconductor device having a T-type gate electrode according to a sixth embodiment of the present invention. The sixth embodiment relates to a method of manufacturing a semiconductor device having a T-type gate electrode using the photomask 100 according to the first embodiment.

In FIG. 7, 7 is a semiconductor substrate of GaAs or the like, 8 is a negative resist of 5000 to 20000 angstrom thickness, or an image reversal resist,
9 is the exposure light, and 81 is the resist 8 with a width of 0.3-0.
A T-type gate electrode resist formed by forming a T-type opening 80 having an opening 88 of 4 μm, a maximum width of about 2 μm, and an upper opening 85 having a depth that leaves the resist film thickness of about 1000 to 2000 angstroms. Pattern, 7
Reference numeral 1 denotes a recess groove formed in the semiconductor substrate 7 and having a width of 500 to 3000 angstroms, which is wider than the opening 88 and has a central electrode portion (lower electrode portion) 10a and an upper electrode portion 10b. Type gate electrode.

Next, a method of manufacturing the semiconductor device having the T-type gate electrode of the sixth embodiment will be described with reference to FIGS.
First, as shown in FIG.
A negative resist or image reversal resist 8 is formed by coating with a thickness of about 0 to 20,000 angstroms.

Next, as shown in FIG. 7B, the resist film 8 is exposed by the reduction projection exposure method such as photolithography using the photomask 100 shown in the first embodiment. Then, when the unexposed portion at the time of this exposure is developed, the width of the central opening 88 as shown in FIG.
A resist pattern having a T-shaped opening 80 having a thickness of 0.4 μm, the resist film thickness on both sides thereof is set to about 1000 to 2000 Å, and the entire opening width of the upper opening 85 is about 2 μm at the maximum. 81 can be obtained.

Further, using the resist pattern 81 as a mask, the semiconductor substrate 7 is wet-etched using a mixed solution of tartaric acid and hydrogen peroxide through the opening 88 having an opening width of 0.3 to 0.4 μm. To form a recess groove 71 having an opening width wider than the opening 88 and a depth of about 500 to 3000 angstroms, and in this state, a metal serving as a gate electrode is vapor-deposited and a lift-off method is performed. As a result, as shown in FIG. 7D, a gate electrode central portion 10a having a gate length corresponding to the opening 88 having the opening width of 0.3 to 0.4 μm, and
The T-type gate electrode 10 having the upper electrode portion 10b corresponding to the upper opening 85 having a maximum of about 2 μm is obtained.

As described above, in the method of manufacturing the semiconductor device having the T-type gate electrode using the photomask for forming the T-type gate electrode of the first embodiment according to the sixth embodiment, the T-type gate electrode 10 is formed once. Since the resist pattern 81 for forming the T-type gate electrode 10 can be formed by exposure, that is, the resist pattern 81 for forming the T-type gate electrode 10 can be formed by one-time exposure with respect to the single-layer negative resist. It is possible to shorten the manufacturing process and increase the throughput of semiconductor device manufacturing.

Further, since the gate central electrode portion 10a, which is a portion for forming the gate length of the T-type gate, and the upper electrode portion 10b of the T-type gate are formed at the same time, there has been a problem in the prior art. It is possible to greatly improve the overlay position accuracy of the gate central electrode portion and the upper electrode portion, and it is possible to improve the uniformity of the product.

Example 7 FIG. 8 is a sectional view showing a method of manufacturing a semiconductor device having a T-type gate electrode according to a seventh embodiment of the present invention. This example relates to a method of manufacturing a semiconductor device having a T-type gate electrode by using the photomask 600 described in the fifth example.

In FIG. 8, the same reference numerals as those in FIG. 6 indicate the same or corresponding portions, 7 is a semiconductor substrate, 82 is a positive resist, 91 is exposure light, and 83 is a T-type gate electrode resist pattern.

The method of manufacturing the semiconductor device having the T-type gate electrode according to this embodiment will be described below. First,
As shown in FIG. 8A, 5000 to 2 are formed on the semiconductor substrate 7.
A positive resist 82 is applied and formed to a thickness of about 0000 angstrom.

Next, as shown in FIG. 8B, the resist film 82 is exposed by a reduction projection exposure method such as photolithography using the photomask 600 of the fifth embodiment. Then, when the exposed portion at the time of this exposure is developed, FIG. 8 (c)
The T-type gate electrode resist pattern 83 shown in can be obtained.

Further, by using the resist pattern 83 as a mask, the glass substrate 1 is etched by wet etching using a mixed solution of tartaric acid and hydrogen peroxide solution, whereby a depth of about 500 to 3000 angstroms is obtained. A recess groove (corresponding to 71 in FIG. 7) is formed, and a T-shaped gate electrode (corresponding to 10 in FIG. 7) is formed by vapor deposition and a lift-off method.

As described above, according to the seventh embodiment, in the method of manufacturing the semiconductor device having the T-type gate electrode using the T-type gate electrode forming photomask 600 of the fifth embodiment,
Since the resist pattern for forming the mold gate electrode can be formed by exposing the single positive resist once, the throughput in manufacturing the semiconductor device can be increased. Further, the gate electrode central portion 10a of the T-shaped gate electrode and the upper electrode portion 10 of the T-shaped gate are formed.
Since b and b are formed at the same time, the central portion 10a of the gate electrode and the upper electrode portion 10 which have been a conventional problem have been formed.
This has the effect of significantly improving the accuracy of the position of superimposition with b.

[0076]

As described above, according to the photomask for forming a T-type gate electrode and the manufacturing method thereof according to the present invention, it corresponds to the central portion of the T-type gate electrode on the transparent substrate for the photomask. A pair of light-shielding films, each having a size that does not allow the resist to be resolved, are formed at positions symmetrical with respect to the position, and the phase of the exposure light when the exposure light passes through the photomask in the photolithography process. Is formed so that the pattern edge is located at the center of the pair of light-shielding films and covers one of the light-shielding films, and the exposure light is transmitted through the photomask in the photolithography process. The light intensity distribution of the exposure light obtained on the wafer has an extremely small dark portion corresponding to the central portion of the T-shaped gate electrode and a minute dark portion corresponding to the upper portion of the T-shaped gate electrode. Since it has a T-shaped light intensity distribution having, T-shaped gate electrode formation capable of obtaining exposure light having a T-shaped light intensity distribution centered on the central portion of the T-shaped gate electrode There is an effect that a photomask for use can be obtained, and the photomask can be easily manufactured.

According to the invention, in the T-type gate electrode forming photomask, a shifter for inverting the phase of the exposure light is formed by digging the photomask transparent substrate by a required thickness. As a result, even if dust adheres to the photomask, it can be removed by washing with a brush, etc.
There is an effect that something that does not need to be corrected can be obtained.

Further, according to the method of manufacturing the semiconductor device having the T-type gate electrode of the present invention, the T-type gate electrode of the semiconductor device is formed by using the photomask for forming the T-type gate electrode. When a negative or image reversal resist is used, a T-shaped light intensity distribution necessary for forming a T-shaped gate electrode is obtained on a wafer by one exposure, and a resist pattern having a T-shaped opening is obtained. Since there is no need to perform overlay exposure as in the prior art, high throughput and high precision T
There is an effect that a mold gate electrode can be formed.

Further, according to the photomask for forming a T-type gate electrode and the method for manufacturing the same according to the present invention, a transparent pattern having a pattern corresponding to the central portion of the T-type gate electrode provided on the transparent substrate for the photomask is formed. An opening for light and a semi-light-shielding film portion formed on the transparent substrate for the photomask, which is symmetrical with respect to the opening pattern for transmitting light and which corresponds to the upper portion of the T-shaped gate electrode; A light-shielding film portion disposed on both outer sides of the light-shielding film portion, and the light intensity distribution of the exposure light obtained on the wafer by passing the exposure light through the photomask corresponds to a gate length. Komeibe,
An inverted T-shaped light intensity distribution having a minute bright portion corresponding to a portion to be the T-shaped gate upper electrode is obtained, and the inverted T-shaped light intensity distribution is obtained on the wafer by one exposure.
There is an effect that a photomask for forming the mold gate electrode can be obtained and the photomask can be easily manufactured.

According to the T-type gate electrode forming photomask and the method of manufacturing the same of the present invention, the semi-light-shielding film portion of the T-type gate electrode forming photomask is
Since the resist film is formed in a repeating pattern of a light-shielding film having a size not to be resolved, and the light-shielding film portion is formed by forming the light-shielding film on the entire surface, the repeating pattern of the light-shielding film Thus, it is possible to obtain a semi-light-shielding film portion, to easily obtain a photomask for forming a T-type gate electrode, and to manufacture the photomask more easily by reducing the number of steps.

Further, according to the method of manufacturing the semiconductor device having the T-type gate electrode according to the present invention, the light-shielding film portion and the semi-light-shielding film portion are symmetrically arranged about the gate electrode portion on the photomask transparent substrate. A T-shaped gate electrode is formed in such a manner that Since the T-type gate electrode of the semiconductor device is formed by using the photomask for use in the semiconductor device, the reverse T-shaped light intensity distribution necessary for forming the T-type gate electrode can be obtained in one exposure by using the positive resist. A resist pattern having a T-shaped opening can be obtained on a wafer, and there is no need to perform overlay exposure as in the conventional technique, and a high throughput and highly accurate T-shaped gate electrode is formed. can do There is a result.

[Brief description of drawings]

FIG. 1 is a diagram showing the structure and principle of a T-type gate electrode forming photomask according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a photomask manufacturing flow for manufacturing the photomask of Example 1;

FIG. 3 is a diagram showing a structure of a T-type gate electrode forming photomask according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a structure of a T-type gate electrode forming photomask according to a third embodiment of the present invention, and an exposure light amplitude distribution and a light intensity distribution.

FIG. 5 is a view showing the structure of a T-type gate electrode forming photomask according to a fourth embodiment of the present invention.

FIG. 6 is a diagram showing a structure of a T-type gate electrode forming photomask and a light intensity distribution of exposure light according to a fifth embodiment of the present invention.

FIG. 7 is a flow of a method for forming a resist pattern for forming a T-type gate electrode in a method for manufacturing a semiconductor device having a T-type gate electrode according to a sixth embodiment of the present invention, which uses the photomask according to the first embodiment. , And FIG. 9 is a cross-sectional view showing a semiconductor device having a T-shaped gate electrode to be finally formed.

FIG. 8 is a flow of a method of forming a resist pattern for forming a T-type gate electrode in a method of manufacturing a semiconductor device having a T-type gate electrode according to a seventh embodiment of the present invention, which uses the photomask of the fifth embodiment. FIG.

FIG. 9 is a cross-sectional view showing a conventional method of manufacturing a T-type gate electrode.

[Explanation of symbols]

100 Photomask for T-type gate electrode formation 1 Glass substrate for photomask 2 Shifter 21 Shifter part 300 Photomask for T-type gate electrode formation 3 Light-shielding film 400 T-type gate electrode formation photomask 30 Light-shielding film part 31 Semi-light-shielding film part 32 Aperture (light-shielding aperture) 4,41 Amplitude distribution of exposure light on the mask 5,51 Amplitude distribution of exposure light on the wafer 6,61,62 Light intensity distribution of exposure light on the wafer 500 T-type gate Photomask for forming electrode 600 Photomask for forming T-type gate electrode 50 Opening 52 Semi-light-shielding portion 53 Light-shielding film 54 Cr film 7 Semiconductor substrate 71,74 Recess groove 8 Negative or image reversal resist 81 T-type gate electrode resist pattern 82 Positive resist 84 Electron beam resist 85 Photoresist 86 Upper layer resist Turn 87 lower resist pattern 88 opening 9,91,92 exposure light 93 electron beam 10, 11 T-shaped gate electrode 10a, 11a T-shaped gate electrode central portion 10b, 11b T-shaped gate electrode upper

Claims (12)

[Claims] 1. A T-type gate electrode forming photomask used for forming a T-type gate electrode on a semiconductor substrate, wherein a position corresponding to a central portion of the T-type gate electrode is formed on a transparent substrate for the photomask. A pair of light-shielding films, each of which has a size that does not allow the resist to be resolved, are formed at symmetrical positions in the center. When the exposure light passes through the photomask in the photolithography process, the phase of the exposure light is inverted. A shifter is formed so that the pattern edge is located at the center of the pair of light-shielding films and covers either one of the light-shielding films. The obtained light intensity distribution of the exposure light has an extremely small dark portion corresponding to the central portion of the T-shaped gate electrode and a minute dark portion corresponding to the upper portion of the T-shaped gate electrode. A T-shaped gate having a T-shaped light intensity distribution having a dark portion, and the T-shaped light intensity distribution is obtained on a wafer by one exposure. Photomask for electrode formation. 2. The T-type gate electrode forming photomask according to claim 1, wherein a shifter for inverting the phase of the exposure light is formed by digging the transparent substrate for the photomask by a required film thickness. And a photomask for forming a T-type gate electrode. 3. A T-type gate electrode forming photomask used for forming a T-type gate electrode on a semiconductor substrate, which corresponds to a central portion of the T-type gate electrode provided on a transparent substrate for a photomask. And a semi-light-shielding film portion formed in a portion corresponding to the upper portion of the T-shaped gate electrode, which is bilaterally symmetrical with respect to the transparent opening for the photomask and the transparent opening pattern for the photomask. And a light-shielding film portion formed on both outer sides of the semi-light-shielding film portion, and the light intensity distribution of the exposure light obtained on the wafer by transmitting the exposure light through the photomask is the T-type gate. The T-shaped gate electrode has an extremely small bright portion corresponding to the central portion and a minute bright portion corresponding to the portion above the T-shaped gate electrode, and has an inverted T-shaped light intensity distribution. The light intensity distribution of T-type gate electrode formation photomask, characterized in that is obtained on the wafer. 4. The photomask for forming a T-type gate electrode according to claim 3, wherein the semi-light-shielding film portion is provided on both sides of the light-transmitting opening pattern on the transparent substrate for the photomask. Including the position where the film portion is to be formed, a light-shielding film having a required film thickness, which will be the light-shielding film portion on the outside thereof, is formed, and a portion where the semi-light-shielding film portion inside the formed light-shielding film is to be formed is formed. A photomask for forming a T-type gate electrode, which is formed by etching to a predetermined film thickness. 5. The photomask for forming a T-type gate electrode according to claim 3, wherein the semi-light-shielding film portion is formed on both sides of the light-transmitting opening pattern on the transparent substrate for the photomask. Is formed by forming a light-shielding film at the position where the portion is to be formed, and then implanting ions at the position where the semi-light-shielding film portion is to be formed on the transparent substrate for the photomask. Photomask for forming T-type gate electrode. 6. The photomask for forming a T-type gate electrode according to claim 3, wherein the semi-light-shielding film portion is formed by a repeating pattern of light-shielding films having a size that does not resolve a resist film. A photomask for forming a T-type gate electrode, wherein the film portion is formed by forming a light-shielding film on the entire surface. 7. A method of manufacturing a T-type gate electrode forming photomask for forming a T-type gate electrode on a semiconductor substrate, comprising: forming a light-shielding film on one surface of a transparent substrate for a photomask; Patterning to form a pair of light-shielding films, each of which has a size not to be resolved by a resist, at symmetrical positions with respect to a position corresponding to the center of the T-shaped gate electrode. After forming the light-shielding film on the transparent substrate for use on the whole surface, after forming a shifter material for inverting the phase of the exposure light when the exposure light passes through the photomask,
And a step of patterning this so that the pattern edge is located at the center of the pair of light-shielding films and covers either one of the light-shielding films. The light intensity distribution of the exposure light obtained above is a T-shaped light intensity distribution having a very small dark portion corresponding to the central portion of the T-shaped gate electrode and a minute dark portion corresponding to the upper portion of the T-shaped gate electrode. A method of manufacturing a photomask for forming a T-type gate electrode, which comprises manufacturing such a photomask for forming a T-type gate electrode. 8. A method of manufacturing a T-type gate electrode forming photomask used for forming a T-type gate electrode on a semiconductor substrate, comprising a step of forming a light-shielding film on one surface of a transparent substrate for photomask. A step of forming an opening in the light-shielding film at a position corresponding to the central portion of the T-type gate electrode; and a step of symmetric with respect to the opening pattern of the light-shielding film on the photomask transparent substrate. A step of etching a portion corresponding to the upper portion of the T-shaped gate electrode to a thickness of about half to form a semi-shielding film, and leaving portions on both sides thereof as the shielding film as it is. And a light intensity distribution of exposure light obtained on the wafer after passing through is a very small bright portion corresponding to the central portion of the T-shaped gate electrode and a minute bright portion corresponding to the upper portion of the T-shaped gate. To Method for producing a T-shaped gate electrode forming a photomask, characterized by producing an inverted T-shaped T-shaped gate electrode forming a photomask such that the light intensity distribution of the. 9. A method of manufacturing a photomask for forming a T-type gate electrode used for forming a T-type gate electrode on a semiconductor substrate, comprising the step of forming a light-shielding film on one surface of a transparent substrate for a photomask. A step of forming an opening in the light shielding film, the opening including a position corresponding to a central portion of the T-type gate electrode and a position corresponding to an upper portion of the T-type gate electrode; and the opening on the transparent substrate for the photomask. Ions are implanted into a portion corresponding to the upper portion of the T-shaped gate electrode, which is symmetrical with respect to the opening pattern except a position corresponding to the central portion of the T-shaped gate electrode, to form a semi-light-shielding portion. And a T-type gate electrode, in which the light intensity distribution of the exposure light obtained by transmitting the exposure light through the photomask through the photomask corresponds to the central portion of the gate electrode A photomask for forming a T-type gate electrode, the photomask for forming a T-type gate electrode having an inverted T-shaped light intensity distribution having a minute bright portion corresponding to a portion to be a portion is manufactured. Production method. 10. A method of manufacturing a photomask for forming a T-type gate electrode used for forming a T-type gate electrode on a semiconductor substrate, the method comprising: forming a light-shielding film on one surface of a transparent substrate for a photomask. At the position corresponding to the central part of the T-type gate electrode of the light-shielding film, the whole is an opening, and at the position corresponding to the upper part of the T-type gate electrode on the outer side thereof, the light-shielding film and the opening are resist. A repeating pattern of a light-shielding film having a size that does not resolve the film is formed, and a step of forming an opening on the outer side of the light-shielding film is formed so that the light-shielding film remains formed. The light intensity distribution of the exposure light obtained on the wafer has an extremely small bright portion corresponding to the central portion of the T-shaped gate electrode and a minute bright portion corresponding to the upper portion of the T-shaped gate electrode. A method of manufacturing a T-type gate electrode forming photomask, comprising manufacturing a T-type gate electrode forming photomask having a T-shaped light intensity distribution. 11. A method for manufacturing a semiconductor device having a T-type gate electrode using a T-type gate electrode forming photomask, the method comprising coating and forming a negative or image reversal type photoresist on a semiconductor substrate, A step of exposing the resist film by photolithography using the photomask for forming a T-shaped gate electrode according to claim 1, and a resist pattern having an opening with a T-shaped cross section, which is developed by exposing the exposed resist film. And a step of forming a recess groove on the semiconductor substrate surface by performing wet etching using the resist pattern as a mask, and a gate metal is vapor-deposited using the resist pattern as a mask to form a gate electrode in the recess groove. And a step of removing unnecessary metal by a lift-off method. The method of manufacturing a semiconductor device having a. 12. A method of manufacturing a semiconductor device having a T-type gate electrode using a T-type gate electrode forming photomask, the method comprising coating and forming a positive-type photoresist on a semiconductor substrate. A step of exposing the resist film by photolithography using the T-shaped gate electrode forming photomask, and a step of developing the exposed resist film to form a resist pattern having an opening with a T-shaped cross section. A step of performing wet etching using the resist pattern as a mask to form a recess groove on the surface of the semiconductor substrate; and forming a gate electrode in the recess groove by vapor-depositing a gate metal using the resist pattern as a mask, and performing a lift-off method. A method of manufacturing a semiconductor device having a T-shaped gate electrode, the method including: .