KR100943506B1 - Phase Shift Mask and Method of manufacturing the same - Google Patents

Abstract

A phase shift mask and a method of manufacturing the same are provided. The phase shift mask may include a reticle substrate, a first opening pattern formed in a first region of the reticle substrate to transmit light, and a second opening formed in a second region of the reticle substrate around the first opening pattern to transmit light. And a third opening pattern formed in a third region of the reticle substrate to surround the first opening pattern between the first opening pattern and the second opening pattern, and blocking light.

Reticle, phase shift mask.

Description

Phase Shift Mask and Method of manufacturing the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for manufacturing a semiconductor device, and more particularly, to a phase shift mask used in an exposure process for manufacturing a semiconductor device.

Current semiconductor device manufacturing technology requires high integration. For example, the line width reduction technology of the gates of MOSFETs is closely related to the high integration of semiconductor devices, and much effort has been made to reduce the line widths of the gates of MOSFETs.

In order to form the contact hole pattern of the semiconductor device, it is first required to form a photoresist pattern using a photolithography process. As a light source used in the exposure process for forming the photoresist pattern, a KrF light source having a wavelength of 248 nm or an ArF light source having a wavelength of 193 nm is used.

However, an exposure process using an ArF light source is more expensive than an exposure process using a KrF light source, and may cause a manufacturing cost of a semiconductor device to be increased. Therefore, the cost of forming the photoresist pattern for the contact hole pattern using the KrF light source is advantageous in terms of cost, but the disadvantage is that the contact hole pattern is not formed properly as the depth of focus (DOF) margin is reduced. have.

FIG. 1A illustrates a layout of a general NOR flash memory device, and FIG. 1B illustrates a cross-sectional view of the layout shown in FIG. 1A in the A-A 'direction. 1A and 1B, the layout may include a semiconductor substrate 100, gate lines (eg, 110, 120, 130, and 140: also referred to as "word lines"), common source regions (eg, CS1, CS2), drain regions (eg, D1, D2), drain contacts (eg, 105-1 to 105- (N), 107-1 to 107- (M): natural numbers where N> 1, M> A natural number of one), common source contacts (eg, 106, 106-1, 108, 108-1).

The gate lines (eg, 110 and 120) may be formed by stacking a floating gate 102, an oxide-nitride-oxide (ONO) layer, and a control gate, and spacers 122, 123, 124, and 125 on both sides of the gate lines. ) May be formed.

The common source regions (eg, CS1) are formed in the semiconductor substrate 100 between gate lines (eg, 110 and 120), and the common source regions (eg, CS1) and the drain regions (eg, D1) is formed with the gate lines (eg, 110 and 120) interposed therebetween.

FIG. 2A illustrates drain contact holes (eg, 107-1) corresponding to drain contacts (eg, 107-1, 107-2, and 107-3) of the NOR flash memory device shown in FIG. 1A formed using a KrF light source. ', 107-2', and 107-3 '). As shown in FIG. 2A, when the drain contact holes of the NOR flash memory device are formed using the KrF light source, the process margin is not sufficiently secured, so that the drain contact holes (eg, 107-1 ', 107-2', and 107- 3 ') may not be formed properly.

In order to solve this problem, a dipole or quadruple type illumination system is used instead of the conventional or annular type illumination system used in the exposure process. have.

2B illustrates drain contact holes of a NOR flash memory device formed using a dipole or quadruple illumination system. As shown in FIG. 2B, drain contact holes (eg, 107-1 ″ and 107-2 ′) are arranged in a predetermined direction when using a KrF light source but using a dipole or quadruple type illumination system. ', And 107-3' ') can be improved.

However, when using a dipole or quadruple illumination system, the process margin of the drain contact holes (eg, 107-1 '', 107-2 '', and 107-3 '') can be improved. Around the cell edge contact hole of the NOR flash memory device cell, that is, the contact hole 106-1 '(hereinafter referred to as "common source contact hole") for forming common source contacts (e.g., 106-1). Side lobes (S1 to S4) may be generated.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a phase shift mask capable of preventing side lobes that may occur when a contact hole of a 90 nm NOR flash memory device is formed using a KrF light source, and a method of manufacturing the same.

According to an embodiment of the present invention, a phase shift mask may include a reticle substrate, a first opening pattern formed in a first region of the reticle substrate to transmit light, and the first opening. A second opening pattern formed in a second region of the reticle substrate around the pattern to transmit light, and a third region of the reticle substrate to surround the first opening pattern between the first opening pattern and the second opening pattern It is formed in, and comprises a third opening pattern for blocking the light.

According to another aspect of the present invention, there is provided a method of manufacturing a phase shift mask, including forming a molybdenum silicide layer on a reticle substrate, a first opening, a second opening, and a third opening on the molybdenum silicide layer. Forming a first photoresist pattern having an opening, etching the molybdenum silicide layer using the first photoresist pattern, and then removing the first photoresist pattern to expose the reticle substrate; Forming a second opening pattern, and a third opening pattern, and embedding chromium or TiN in the third opening pattern to form a blocking pattern, wherein the third opening includes the first opening and the second opening; It is formed between the opening, and is spaced apart from the first opening is formed to surround the first opening.

A phase shift mask and a method of manufacturing the same according to an exemplary embodiment of the present invention use a blocking pattern that blocks light when a contact hole of a 90 nm NOR flash memory device is formed using a KrF light source, and between a common source contact hole and a drain contact hole. There is an effect that can prevent the side lobe that may occur in.

Hereinafter, the technical objects and features of the present invention will be apparent from the description of the accompanying drawings and the embodiments. Looking at the present invention in detail.

3A is a plan view of the phase shift mask 300 according to the exemplary embodiment of the present invention, and FIG. 3B is a cross-sectional view of the phase shift mask 300 shown in FIG. 3A in the B-B 'direction.

3A and 3B, the phase shift mask 300 may include a reticle substrate 310, a MoSi layer 320, a first opening pattern 340, a second opening pattern 320-1, 320-2, 330-1 and 330-2, and a blocking pattern 350.

The first opening pattern 340 is formed on the reticle substrate 310 and transmits light. The second opening patterns 320-1, 320-2, 330-1, and 330-2 are formed on the reticle substrate 310 around the first opening pattern 240 and transmit light. The blocking pattern 350 is formed on the reticle substrate 310 between the first opening pattern 340 and the second opening patterns 320-1, 320-2, 330-1, and 330-2. Block the light.

Herein, the reticle substrate except for the region in which the first opening pattern 340, the second opening patterns 320-1, 320-2, 330-1, and 330-2, and the blocking pattern 350 are formed is light. 6 to 10% can be transmitted.

For example, as illustrated in FIG. 3B, the first opening pattern 340, the second opening patterns 320-1, 320-2, 330-1, 330-2, and the blocking pattern 350 may be disposed. The MoSi layer 320 is formed on the excepted reticle substrate 310. The MoSi layer 320 may transmit 6 to 10% of light, and the first opening pattern 340 and the second opening patterns 320-1, 320-2, 330-1, on which the MoSi layer is not formed 330-2) transmits all the light. In addition, a chromium (Cr) layer or a TiN layer 350 is formed on an area of the reticle substrate on which the blocking pattern is to be formed, and the chromium layer or TiN layer 350 blocks light.

The second opening patterns 320-1, 320-2, 330-1, and 330-2 have four opening patterns 320-1 based on the first opening pattern 340 as shown in FIG. 3A. , 320-2, 330-1, and 330-2 may be arranged in a square shape.

The blocking pattern 350 is disposed between the first opening pattern 340 and the second opening patterns 320-1, 320-2, 330-1, and 330-2, and the first opening pattern 340. It may be formed to surround). In this case, a position where the blocking pattern 350 is formed may be located in the middle between the first opening pattern 340 and the second opening pattern.

The first opening pattern 340 illustrated in FIG. 3A is formed to correspond to the common source contact hole of the NOR flash memory device, and the second opening patterns 320-1, 320-2, 330-1, and 330-2 are The drain contact hole adjacent to the common source contact hole may be formed.

The other opening patterns 320-3 to 320-6 and 330-3 to 330-6 shown in FIG. 3A may be formed to correspond to the remaining drain contact holes of the NOR flash memory device.

5A to 5H are cross-sectional views illustrating a method of manufacturing the phase shift mask 300 shown in FIG. 3A. 5A through 5H are cross-sectional views taken along the line C-C 'of the phase shift mask 300 shown in FIG. 3A.

First, as shown in FIG. 5A, a molybdenum silicide layer 320-1 (hereinafter referred to as MoSi layer) is formed on the quartz substrate 310. Next, as shown in FIG. 5B, a first photoresist pattern 510 is formed on the MoSi layer 320-1.

The first photoresist pattern 510 has a first opening, a second opening, and a third opening. The third opening may be formed between the first opening and the second opening and may be spaced apart from the first opening to surround the first opening.

For example, the first photoresist pattern 510 may include a first opening 512 and a second opening pattern (eg, 330-1 and 320-2) corresponding to the first opening pattern 340 shown in FIG. 3A. It may be patterned to have second openings 514 and 515 corresponding to the third openings 516 and 517 corresponding to the blocking pattern 350.

Next, as shown in FIG. 5C, the MoSi layer 320-1 is etched using the first photoresist pattern. Subsequently, as illustrated in FIG. 5D, the first photoresist pattern is removed through an ashing and stripping process to remove the first opening pattern (eg, 340), the second opening pattern (eg, 330-1 and 320-2), And third opening patterns 516-1 and 517-1 for the blocking pattern 350.

Next, the blocking pattern 350 is formed by filling chromium (Cr) or TiN 350-1 only in the third opening patterns 516-1 and 517-1.

5E to 5H illustrate an embodiment of the present invention for forming the blocking pattern. As shown in FIG. 5E, the first opening patterns 512, the second opening patterns 514 and 515, and the chromium (Cr) or TiN 350-1 are coated on the entire surface of the reticle substrate 310. Third opening patterns 516 and 517 are embedded.

Next, as shown in FIG. 5F, the coated chromium (Cr) or TiN 350-1 is planarized through chemical mechanical polishing (CMP). Next, as illustrated in FIG. 5G, chromium (Cr) or TiN 350-1 embedded in the first opening patterns (eg, 340) and the second opening patterns (eg, 330-1 and 320-2). The second photoresist pattern 360 exposing the photoresist is formed on the reticle substrate 310 on which the CMP process is performed.

Next, as shown in FIG. 5H, the exposed second chromium (Cr) or TiN 350-1 is removed by wet or dry etching using the second photoresist pattern 360 and then the second photoresist pattern. Remove 360.

The phase shift mask illustrated in FIGS. 3A and 5H may be a mask for patterning the common source contact hole and the drain contact hole of the NOR flash memory device.

The first opening pattern (eg, 340) may be disposed on the reticle substrate 310 corresponding to a common source contact hole of a NOR flash memory device, and the second opening patterns (eg, 320-1 and 320-2). , 330-1, 330-2 may be disposed on the reticle substrate 310 corresponding to drain contact holes adjacent to the common source contact hole.

4A is a graph (g1) illustrating the intensity of light transmitted when performing an exposure process using a general mask, and FIG. 4B is a graph of light transmitted when performing an exposure process using the phase shift masks shown in FIGS. 3A and 5H. It is a graph g2 showing intensity.

According to FIG. 4A, side light overlaps between the first opening pattern 340 and the second opening patterns 330-1 and 320-2 to form patterns S2 and S3 having a small ring shape. That is, side lobes S1 and S3 as shown in FIG. 2C are formed.

However, as shown in FIG. 4B, the side light is prevented from overlapping by the blocking pattern 350 formed between the first opening pattern 340 and the second opening patterns 330-1 and 320-2. Therefore, when the common source contact hole and the drain contact hole of the NOR flash memory device are patterned using the phase shift mask 300 according to the exemplary embodiment of the present disclosure, side lobe generation may be prevented.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

1A shows the layout of a typical NOR flash memory device.

FIG. 1B is a sectional view taken along the line AA ′ of the layout shown in FIG. 1A.

FIG. 2A illustrates drain contact holes corresponding to the drain contacts of the NOR flash memory device shown in FIG. 1A formed using a KrF light source.

2B illustrates drain contact holes of a NOR flash memory device formed using a dipole or quadruple illumination system.

3A is a plan view of a phase shift mask according to an exemplary embodiment of the present invention.

FIG. 3B is a sectional view taken along the line B-B 'of the phase shift mask shown in FIG. 3A.

4A is a graph showing the intensity of light transmitted when performing an exposure process using a general mask.

FIG. 4B is a graph showing the intensity of light transmitted when performing an exposure process using the phase shift mask shown in FIGS. 3A and 5H.

5A to 5H are cross-sectional views illustrating a method of manufacturing the phase shift mask shown in FIG. 3A.

Claims (8)

Reticle substrates; A first opening pattern formed in a first region of the reticle substrate to transmit light; A second opening pattern formed in a second area of the reticle substrate around the first opening pattern to transmit light; And And a third opening pattern formed in a third region of the reticle substrate to surround the first opening pattern between the first opening pattern and the second opening pattern, and blocking light. The method of claim 1, wherein the reticle substrate, And a region of the reticle substrate on which the first opening pattern, the second opening pattern, and the third opening pattern are not formed transmits 6 to 10% of light. The method of claim 1, wherein the second opening pattern, Phase shift mask, characterized in that the four opening patterns are formed in a quadrangular shape around the first opening pattern. The method of claim 1, The first opening pattern, Disposed on the reticle substrate corresponding to a common source contact hole of a NOR flash memory device, The second opening pattern is, And a phase shift mask disposed in the reticle substrate corresponding to drain contact holes adjacent to the common source contact hole. The method of claim 1, wherein the third opening pattern, The phase shift mask is formed to surround the first opening pattern, and is disposed to be disposed at the same distance from the first opening pattern and the second pattern. The method of claim 2, wherein the phase shift mask, And further comprising a MOSi layer formed on an area of the reticle substrate on which the first opening pattern, the second opening pattern, and the third opening pattern are not formed so as to transmit 6 to 10% of light. Mask. Forming a molybdenum silicide layer on the reticle substrate; Forming a first photoresist pattern having a first opening, a second opening, and a third opening on the molybdenum silicide layer; Etching the molybdenum silicide layer using the first photoresist pattern, and then removing the first photoresist pattern to form a first opening pattern, a second opening pattern, and a third opening pattern exposing the reticle substrate. step; And Embedding chromium or TiN in the third opening pattern to form a blocking pattern; And the third opening is formed between the first opening and the second opening and is spaced apart from the first opening to surround the first opening. The method of claim 7, wherein forming the blocking pattern, Filling the first opening pattern, the second opening pattern, and the third opening pattern by coating chromium or TiN on the entire surface of the reticle substrate; Planarizing the applied chromium or TiN through chemical mechanical polishing (CMP); Forming a second photoresist pattern exposing chromium (Cr) or TiN (350-1) embedded in the first opening pattern and the second opening pattern on the reticle substrate subjected to the CMP process; And And removing the second photoresist pattern after removing chromium or TiN exposed by using the second photoresist pattern through wet or dry etching.

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