KR101067858B1 - Photo mask, method for manufacturing the photo mask and method for manufacturing the semiconductor device using the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure mask, a method of manufacturing an exposure mask, and a method of manufacturing a semiconductor device using the same. In particular, in an exposure process using a polarization illumination system, a phase retarder having a different thickness for each region may be applied to an exposure mask. It is a technology that can improve the yield and reliability of the device by increasing the exposure process margin by adjusting the direction of the polarization used as an exposure light source, including.

Description

Exposure mask, manufacturing method of exposure mask and manufacturing method of semiconductor device using the same

1 is a conceptual view showing an exposure apparatus with an exposure mask according to the present invention.

2 and 3 are cross-sectional views showing an exposure mask according to the present invention.

4A to 4D are cross-sectional views illustrating a method of manufacturing an exposure mask according to the present invention.

5 is a sectional view showing an exposure mask according to the present invention;

<Explanation of symbols for the main parts of the drawings>

110: illumination system 120, 220, 320, 420, 520: polarized light

130, 230, 330, 430, 530: phase delay layer

140, 240, 340, 440, 540: Exposure Mask

142, 242, 342, 442, 542: transparent substrate

144, 244, 344, 444, 544: shading pattern

150: condenser lens 160: wafer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure mask, and more particularly, to an exposure mask using an improved polarization illumination system, a method of manufacturing an exposure mask, and a method of manufacturing a semiconductor device using the same.

In general, a semiconductor device such as a dynamic random access memory (DRAM) is composed of a large number of fine patterns, which are formed through a photolithography process.

In the photolithography process, resolution and depth of focus (DOF) are known as two important issues.

Among them, the resolution R may be represented by Equation 1 below.

In Equation 1 below, k1 is a constant determined by photosensitive film type, thickness, and the like, λ is a wavelength of a light source to be used, and NA (Numerical Aperture) means a numerical aperture of exposure equipment.

As can be seen from Equation 1, the shorter the wavelength λ of the light source to be used, and the larger the numerical aperture NA of the exposure apparatus, the smaller patterns can be implemented on the wafer.

Currently, the degree of integration of the device is rapidly increasing, but the wavelength (λ) of the light source used and the numerical aperture (NA) of the exposure equipment cannot keep up with this.

Resolution enhancement technology (RET) has been applied to improve resolution and depth of focus using various methods.

Such resolution enhancement techniques may include Phase Shift Mask (PSM), Off-Axis Illumination (OAI), and Optical Proximity Correction (OPC). In order to realize a small pattern, a technique using a polarization component of light has been proposed.

The semiconductor device is implemented in various patterns, and polarized illumination of various directions is required. However, obtaining additional polarization illumination in various directions requires a lot of additional costs. Therefore, there is a problem that the kind of polarized light that can be used in the current exposure process is limited.

The present invention is to solve the above problems, in particular by including a phase retarder (Phase retarder) having a different thickness for each area in the exposure mask in the exposure process using a polarization illumination system, thereby varying the polarization direction that can be used in the exposure process The present invention provides an exposure mask, an exposure mask manufacturing method, and a method of manufacturing a semiconductor device using the same, which can be changed so as to increase the exposure process margin and improve the yield and reliability of the device.

The present invention is to achieve the above object,

A phase retardation layer changing a predetermined polarization direction provided by the polarization illuminator and having a different thickness for each region;

And a light blocking pattern under the phase delay layer.

The phase delay layer may be configured to change a polarization direction according to the light shielding pattern direction,

The light shielding pattern is in the form of a line,

The phase retardation layer is characterized in that it is changed perpendicular to the cycle direction of the light shielding pattern.

In addition, the manufacturing method of the exposure mask

Forming a phase delay layer on the transparent substrate having the light blocking patterns in the first direction and the second direction;

Partially etching the phase retardation layer in the region provided with the light blocking pattern in the first direction;

And partially etching the phase retardation layer in the region with the light blocking pattern in the second direction, but having a thickness different from the phase retardation layer in the region with the light blocking pattern in the first direction. and,

The first direction and the second direction are perpendicular to each other,

The phase retardation layer has a thickness of λ / 4 or 3λ / 4,

The light shielding pattern may be in the form of a line.

In addition, a method of manufacturing a semiconductor device using the exposure mask

In the manufacturing method of the semiconductor element using the exposure apparatus provided with the polarizing illumination system,

Changing light having a polarization direction provided by a polarization illuminator through the phase retardation layer;

And transferring the predetermined pattern included in the exposure mask onto the wafer using light having a changed polarization direction through the phase delay layer.

The principle of the present invention is that after the light having a predetermined polarization passes through a phase retarder, the polarization direction is changed to obtain light having a polarization direction parallel to a desired pattern.

For example, when using a circularly polarized light source for the illumination system in the exposure process, a phase retardation layer having a thickness of 1/4 at the wavelength? Of the exposure light source is attached to the exposure mask back surface.

After the circularly polarized exposure light source passes through the phase retardation layer, it is changed to linearly polarized light parallel to the pattern to improve the exposure process margin.

On the other hand, in the exposure process with respect to the light shielding pattern of the direction perpendicular | vertical to the said light shielding pattern, the phase retardation layer which has a thickness of 3 (lambda) / 4 is attached to the exposure mask back surface.

Hereinafter, with reference to the accompanying drawings an embodiment of the present invention will be described in detail.

1 is a conceptual diagram illustrating an exposure apparatus according to the present invention.

Here, the exposure apparatus includes an illumination system 110, a phase retarder 130, an exposure mask 140, a condenser lens 150, and a wafer 160. The illumination system 110 uses a polarized light having a predetermined polarization direction as the exposure light source to improve the exposure process margin. The phase delay layer 130 is positioned between the illumination system 110 and the exposure mask 140 and is applied to change the polarization 120 having a predetermined polarization direction provided by the illumination system 110. The exposure mask 140 includes a light shielding pattern 144 for transferring onto the wafer on the transparent substrate 142. The condenser lens 150 is positioned between the exposure mask 140 and the wafer 160 to condense the exposure light source passing through the exposure mask 140 to the wafer 160.

According to the present invention, when the illumination system 110 provides the exposure light source with the polarization 120 having the polarization direction moving from side to side on the ground, the polarization 120 has a λ / 2 thickness (λ: wavelength of the exposure light source). After passing through the phase retardation layer 130 is changed to polarized light having a polarization direction passing through the ground.

Subsequently, the polarized light passes through the transparent substrate 142 and the light shielding pattern 144 of the exposure mask 140 and is then focused on the wafer 160 through the light collecting lens 150.

According to another embodiment of the present invention, it is preferable to change the thickness of the phase retardation layer 130 according to a predetermined polarization direction in the illumination system 110.

In addition, it is preferable to change the thickness of the phase retardation layer 130 according to the direction of the light shielding pattern 144 provided in the exposure mask 140.

According to another embodiment of the present invention, the phase retardation layer 130 is preferably disposed on the back surface of the exposure mask 140 provided with the light blocking pattern 144.

2 is a cross-sectional view illustrating an exposure mask according to an embodiment of the present invention.

2 illustrates that the illumination system changes the polarization direction parallel to the length direction of the light shielding pattern 244 provided in the exposure mask 240 through the phase retardation layer 230 when the illumination system uses the polarization 220 having a circular polarization direction. It shows what to do.

According to an embodiment of the present invention, the phase delay layer 230 preferably has a thickness of λ / 4.

3 is a cross-sectional view illustrating an exposure mask according to another exemplary embodiment of the present invention.

3 illustrates a case in which the illumination system changes the polarization direction parallel to the direction of the light shielding pattern 344 provided in the exposure mask 340 through the phase retardation layer 330 when using the polarization 320 having a circular polarization direction. Shows that.

According to an embodiment of the present invention, the phase delay layer 330 preferably has a thickness of 3λ / 4.

Meanwhile, when the light blocking pattern 244 of the exposure mask 240 of FIG. 2 illustrates the word line pattern of the DRAM device, the light blocking pattern 344 of the exposure mask 340 of FIG. A device isolation pattern perpendicular to the word line pattern is shown.

According to another embodiment of the present invention, when the phase retardation layer 330 has an arbitrary thickness, polarization having an arbitrary elliptic direction may be obtained.

4A to 4D are cross-sectional views illustrating a method of manufacturing an exposure mask according to the present invention.

4A and 4B, the phase delay layer 430 is disposed on the transparent substrate 420 of the exposure mask 440 having the light blocking pattern 444a in the first direction and the light blocking pattern 444b in the second direction. To form.

In this case, the phase delay layer 430 preferably has a λ thickness, and the light blocking pattern 444a in the first direction and the light blocking pattern 444b in the second direction are preferably formed in a line shape.

Next, a first photosensitive film pattern 450 is formed to expose a region where the light blocking pattern 444a in the first direction is formed.

Next, the phase retardation layer 430 is etched using the first photoresist pattern 450 as a mask to have a thickness of λ / 4, and then the first photoresist pattern 450 is removed.

4C and 4D, a second photosensitive film pattern 455 is formed to expose a region where the light blocking pattern 444b in the second direction is formed.

Next, the phase retardation layer 430 is etched using the second photoresist pattern 455 as a mask to have a thickness of 3λ / 4.

Next, the second photoresist pattern 455 may be removed to vary the thickness of the phase retardation layer 430 according to the direction of the pattern, thereby obtaining polarized light having an arbitrary elliptic direction.

5 is a cross-sectional view showing an exposure mask according to the present invention.

Referring to FIG. 5, it can be seen that the phase retardation layer 530 has different thicknesses according to regions of the light blocking pattern 544a in the first direction and the light blocking pattern 544b in the second direction. .

Here, when the illumination system uses circularly polarized light as the exposure light source and passes through the phase retardation layer 530 in a region having a thickness of λ / 4, linearly polarized light parallel to the light shielding pattern 544a in the first direction can be obtained.

In addition, when passing through the phase retardation layer 530 in the region having a thickness of 3λ / 4, it is perpendicular to the linearly polarized light obtained by passing through the phase retardation layer 530 in the region having a thickness of λ / 4, and the light blocking pattern in the second direction is performed. Line light parallel to 544b can be obtained.

Accordingly, the phase delay layer 530 may be exposed using a polarization light source having different polarization directions depending on the areas of the light shielding patterns 544a and 544b provided in the exposure mask 540, thereby maximizing the exposure process margin for each pattern. have.

A method of manufacturing a semiconductor device using an exposure mask according to an embodiment of the present invention is as follows. After the phase retardation layer is changed in accordance with the direction of the exposure pattern in the exposure mask, the polarization direction provided by the polarization illuminator is changed through the phase retardation layer.

Thereafter, the exposure pattern included in the exposure mask may be transferred onto the wafer using an exposure light source having a changed polarization direction through the phase delay layer to form a desired pattern on the wafer.

The present invention is intended to implement an exposure mask using an exposure mask of a chrome pattern, but this is not limited to the exposure mask of a chrome pattern.

In addition, although the present invention as described above is described according to a preferred embodiment, it should be noted that the above embodiment is for the purpose of description and not limitation.

As described above, the exposure mask, the method of manufacturing the exposure mask, and the method of manufacturing the semiconductor device using the same according to the present invention may use polarization in various directions in the exposure process, thereby improving the exposure process margin. Therefore, there is an effect of improving the reliability and yield of the device.

It will be apparent to those skilled in the art that various modifications, additions, and substitutions are possible, and that various modifications, additions and substitutions are possible, within the spirit and scope of the appended claims. As shown in Fig.

Claims (9)

Transparent substrates; A light blocking pattern formed on a rear surface of the transparent substrate; And And a phase retardation layer formed on an upper surface of the transparent substrate and having a different thickness for each region and changing a predetermined polarization direction provided from a polarization illuminator according to an arrangement direction of the light shielding pattern. delete Claim 3 was abandoned when the setup registration fee was paid. The method of claim 1, The light blocking pattern has a line shape. Claim 4 was abandoned when the registration fee was paid. The method of claim 1, And the phase retardation layer is changed perpendicular to the periodic direction of the light shielding pattern. Forming a phase retardation layer on the transparent substrate, the first light blocking pattern having the first direction having a long axis and the second light blocking pattern having the second direction having a long axis; Partially etching the phase retardation layer in the region provided with the first light blocking pattern; And Partially etching the phase retardation layer in the region with the second light blocking pattern, but having a thickness different from that of the phase retardation layer in the region with the first light blocking pattern Exposure mask manufacturing method comprising a. Claim 6 was abandoned when the registration fee was paid. The method of claim 5, And the first direction and the second direction are perpendicular to each other. Claim 7 was abandoned upon payment of a set-up fee. The method of claim 5, And the phase retardation layer has a thickness of λ / 4 or 3λ / 4. Claim 8 was abandoned when the registration fee was paid. The method of claim 5, The first light shielding pattern and the second light shielding pattern is a line mask manufacturing method, characterized in that the form of a line. In the manufacturing method of the semiconductor element using the exposure apparatus provided with the polarizing illumination system, Changing the polarization direction of light provided from the polarization illuminator through the phase retardation layer of the exposure mask; And Transferring the pattern provided on the exposure mask onto the wafer using light having a changed polarization direction through the phase retardation layer; Method of manufacturing a semiconductor device comprising a.

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