KR100909138B1 - Metal pattern formation method of semiconductor device - Google Patents

Abstract

The present invention relates to a method of forming a metal pattern of a semiconductor device, the technical problem to be solved is to secure a process margin and to accurately and finely implement the metal pattern by coating a photoresist with a high absorption coefficient instead of the diffuse reflection prevention film. .

To this end, the present invention provides a metal layer forming step of forming a metal layer on a semiconductor substrate, a photoresist coating step of coating a photoresist having an absorption coefficient of 0.4 to 0.6 on the metal layer, and exposing and developing the photoresist to pattern the photoresist. A method of forming a metal pattern of a semiconductor device includes a photoresist patterning step, a metal layer etching step of etching a metal layer, and a photoresist removal step of removing a photoresist.

Description

Metal pattern formation method of semiconductor device {FABRICATING METHOD OF METAL PATTERN OF SEMICONDUCTOR DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a metal pattern of a semiconductor device. More particularly, a semiconductor device capable of securing a process margin by coating a photoresist having a high absorption coefficient instead of an anti-reflective coating layer and accurately and finely implementing a metal pattern It relates to a metal pattern forming method.

In the method of forming a metal pattern of a semiconductor device, an etching process or an ion implantation process is performed using a photoresist as a mask to form a metal pattern on a semiconductor substrate. Typically, the photoresist pattern is formed by a photolithography process in which a photoresist is coated, exposed using an exposure mask, and then developed. The photoresist pattern is precisely formed by increasing the line width of the pattern with increasing integration of semiconductor devices. Fine CD (Critical Dimensition) control is required.

However, in the photoresist exposure process, light interference from the lower metal layer and incident into the photoresist causes multi-interference of light in the photoresist. As a result, particles such as fine particles and dust are generated in the photoresist pattern, resulting in pattern defects. In addition, when a step is present in the semiconductor substrate, the thickness of the photoresist may be uneven in the stepped portion, causing light reflection or light scattering due to surface grains, and thus the part to be exposed is not exposed or the part that should not be exposed. There is a problem that a notching phenomenon occurs in which the shape of the photoresist pattern is deformed. The occurrence of such pattern defects and notching phenomena not only makes accurate CD implementation difficult, but also leads to a lack of process margins.

In order to solve such a problem, a method of forming an anti-reflective coating (ARC) between the metal layer and the photoresist to prevent the light reflected from the metal layer from entering the photoresist. The anti-reflection film is a thin layer of light absorption photosensitive material used to stably form a microcircuit of 0.18 μm or less, which is essential for producing ultra-high density semiconductors, and is used in semiconductor optical fine circuit processing (lithography) processes. The interadhesive interface and optical properties should be well matched with the high resolution photoresist material. Such an antireflection film is classified as a tarc (top arc) film when coated on the top of the photoresist and a barc (bottom arc) film when coated on the bottom, and a barc material is widely used in the current highly integrated semiconductor process.

On the other hand, although the anti-reflection coating is applied between the metal layer and the layer of the photoresist, the phenomenon that the scrap ratio is six times higher than the process without using the anti-reflection coating occurs. Here, since the scrap rate indicates the ratio of the production wafer to the scrap wafer in the application of ARC or NoARC, the production yield decreases as the scrap rate increases. Therefore, if the anti-reflection coating is applied, the manufacturing cost is further consumed, and the process is more complicated due to the anti-reflection coating.

The present invention is to overcome the above-mentioned conventional problems, an object of the present invention to improve the process margin by coating a photoresist with a high absorption coefficient in place of the anti-reflection film of the semiconductor device, and to accurately and finely The present invention provides a method of forming a metal pattern of a semiconductor device.

In order to achieve the above object, a metal pattern forming method of a semiconductor device according to the present invention includes a metal layer forming step of forming a metal layer on a semiconductor substrate, and a photoresist coating a photoresist having an absorption coefficient of 0.4 to 0.6 on the metal layer. A photoresist patterning step of patterning the photoresist by coating and exposing and developing the photoresist may include a metal layer etching step of etching the metal layer, and a photoresist removal step of removing the photoresist.

In addition, in order to achieve the above object, another method of forming a metal pattern of a semiconductor device according to the present invention includes a metal layer forming step of forming a metal layer on a semiconductor substrate, and a first photo having an absorption coefficient of 0.4 to 0.6 on the metal layer. A first photoresist coating step of coating a resist, a second photoresist coating step of coating a second photoresist on the first photoresist, the first photoresist and the second photoresist by exposure and development Patterning a photoresist patterning step, a metal layer etching step of etching the metal layer, and a photoresist removal step of removing the first photoresist and the second photoresist.

The absorption coefficient of the second photoresist may be lower than the absorption coefficient of the first photoresist.

The second photoresist may have an absorption coefficient of 0.1 to 0.3.

As described above, the metal pattern forming method of the semiconductor device according to the present invention can improve the process margin by coating a photoresist having an absorption coefficient of 0.4 to 0.6, it is possible to reduce the manufacturing cost. In addition, by planarizing the surface of the non-uniform metal layer, it is possible to prevent the notching phenomenon and at the same time to accurately and finely implement the metal pattern.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings such that those skilled in the art may easily implement the present invention.

Referring to FIG. 1, a flowchart of a method of forming a metal pattern of a semiconductor device according to an embodiment of the present invention is shown.

As shown in FIG. 1, a method of forming a metal pattern of a semiconductor device according to an exemplary embodiment of the present invention includes a metal layer forming step (S1), a photoresist coating step (S2), a photoresist patterning step (S3), A metal layer etching step S4 and a photoresist removing step S5 are included.

2A through 2E, cross-sectional views illustrating a method of forming a metal pattern of a semiconductor device according to an exemplary embodiment of the present invention illustrated in FIG. 1 are illustrated. A method of forming a metal pattern of the semiconductor device illustrated in FIG. 1 will be described in detail with reference to FIGS. 2A through 2E.

2A is a cross-sectional view showing the metal layer forming step S1, FIG. 2B is a cross-sectional view showing the photoresist forming step S2, FIG. 2C is a cross-sectional view showing the photoresist patterning step S3, 2D is a cross-sectional view illustrating the metal layer etching step S4, and FIG. 2E is a cross-sectional view illustrating the photoresist removing step S5.

First, as shown in FIG. 2A, in the metal layer forming step S1, the metal layer 13 is formed on the semiconductor substrate 11. At this time, the metal layer 13 is made of a thin aluminum (Al) metal. Forming method for forming the metal layer 13 may be formed by any one method selected from Plasma Enhanced Chemical Vapor Deposition (PECVD), Low Pressure Chemical Vapor Deposition (LPCVD), sputtering, and the like. It does not limit the invention. As such, the metal layer 13 is made of aluminum metal, and its surface may be made of non-uniform surface. For this reason, in the etching process, notching may occur due to diffuse reflection.

Accordingly, as shown in FIG. 2B, in the photoresist coating step S2, the photoresist 15 may be coated on the metal layer 13 instead of the anti-reflective coating. In this case, the photoresist 15 may be selected to have a high absorption coefficient in order to prevent diffuse reflection due to the metal layer 13 having an uneven surface. Therefore, the photoresist 15 may serve as a light absorption photosensitive material layer having a higher absorption rate than that of a conventional photoresist. The photoresist 15 may be formed of any one selected from a knoblock-based resin, a photosensitive agent, a solvent, a poly hydroxy strene (PHS) system, and the like, but the material is not limited thereto.

Next, as shown in FIG. 2C, in the photoresist patterning step S3, the photoresist 15 coated on the metal layer 13 is patterned. The photoresist 15 is formed in a pattern that exposes a predetermined region of the metal layer 13 through exposure and development processes. Here, in the exposure process for patterning the photoresist 15, the photoresist 15 having an absorption coefficient of 0.4 to 0.6 is used to prevent diffuse reflection on the non-uniform metal layer 13.

Therefore, the photoresist 15 may improve the planarization characteristics of the photoresist 15 by adjusting the absorption coefficient of the existing photoresist higher than 0.1 to 0.3 to 0.4 to 0.6. At this time, when the absorption coefficient of the photoresist 15 is less than 0.4, since the absorption coefficient of the diffuse reflection prevention film of the semiconductor element is not reached, the planarization of the nonuniform metal layer 13 formed under the photoresist 15 is completely It can be difficult to achieve. In addition, when 0.6 or more is higher than the absorption coefficient of the anti-reflective coating, the reflected light does not reach the bottom of the photoresist 15, not only the photoresist 15 remains, but also may be difficult to pattern during the patterning process. . The photoresist 15 may change the absorption coefficients of resin and PAC (photo active compound) among knolac resins, photosensitizers, solvents, poly hydroxy strenes (PHS), and the like, respectively, so that the absorption coefficient is 0.4 to 0.6. Can be adjusted. Therefore, the photoresist 15 having a high absorption coefficient may be used as an antireflection film having an excellent absorption rate with respect to light energy incident from the metal layer 13 during the exposure process. In addition, since the photoresist 15 simultaneously plays the role of the antireflection film / photoresist in the conventional metal layer / anti-reflection film / photoresist formation method, it is possible to further increase the process margin by reducing the cost of the process and increasing the production yield.

Next, as illustrated in FIG. 2D, in the metal layer etching step S4, the metal layer 13 is etched using the photoresist 15 as a mask. The metal layer 13 may be etched by using a dry etching method or a wet etching method.

Finally, as shown in FIG. 2E, in the photoresist removing step S5, the photoresist 15 stacked on the metal layer 13 is removed. The photoresist 15 may be removed by any one selected from a sulfuric acid solution, a plasma, and an equivalent thereof, but is not limited thereto.

Referring to FIG. 3, a flowchart of a metal pattern forming method of a semiconductor device according to another embodiment of the present invention is shown.

3 is a metal pattern forming method of a semiconductor device according to another embodiment of the present invention as shown in the metal layer forming step (S1), photoresist coating step (S20), photoresist patterning step (S3), the metal layer An etching step S4 and a photoresist removing step S5 are included.

4A through 4E, cross-sectional views illustrating a method of forming a metal pattern of a semiconductor device according to another exemplary embodiment of the present invention illustrated in FIG. 3 are illustrated. A method of forming a metal pattern of the semiconductor device illustrated in FIG. 3 will be described in detail with reference to FIGS. 4A through 4E.

4A is a cross-sectional view showing the metal layer forming step S1, FIG. 4B is a cross-sectional view showing the photoresist coating step S20, FIG. 4C is a cross-sectional view showing the photoresist patterning step S3, 4D is a cross-sectional view illustrating the metal layer etching step S4, and FIG. 4E is a cross-sectional view illustrating the photoresist removing step S5.

As shown in FIGS. 4A to 4E, the method of forming a metal pattern of a semiconductor device according to another exemplary embodiment of the present invention corresponds to FIGS. 4A to 4E and includes a metal layer forming step S1 and a photoresist coating step S20. ), A photoresist patterning step S3, a metal layer etching step S4, and a photoresist removing step S5.

First, as shown in FIG. 4A, in the metal layer forming step S1, the metal layer 13 is formed on the semiconductor substrate 11. At this time, the metal layer 13 is made of a thin aluminum (Al) metal. The formation method for forming the metal layer 13 is formed by any one selected from Plasma Enhanced Chemical Vapor Deposition (PECVD), Low Pressure Chemical Vapor Deposition (LPCVD), sputtering, and the like. As such, the metal layer 13 may be formed of an aluminum metal, and may be formed of an uneven surface having a predetermined step. For this reason, in the etching process, notching may occur due to diffuse reflection.

As shown in FIG. 4B, the photoresist coating step S20 includes a first photoresist coating step S21 and a second photoresist coating step S22, which may serve as an anti-reflective coating film. In the photoresist coating step S2, first, the first photoresist 25 is coated on the metal layer 13, and then the second photoresist 26 is coated on the first photoresist 25. The double coating is made. In this case, the first photoresist 25 may be selected to have a relatively high absorption coefficient in order to prevent diffuse reflection due to the metal layer 13 having an uneven surface. After that, by coating a conventional second photoresist 26 on the first photoresist 25, the planarization characteristic of the metal layer 13 may be further improved.

Next, as shown in FIG. 4C, in the photoresist patterning step S3, the first photoresist 25 coated on the metal layer 13 and the first photoresist 25 are coated. The second photoresist 26 is simultaneously patterned. The first photoresist 25 and the second photoresist 26 are formed in a pattern of the first photoresist 25 and the second photoresist 26 exposing the metal layer 13 through exposure and development processes. do.

Here, in the exposure process for patterning the first photoresist 25, the absorption coefficient of the first photoresist 25 is adjusted to 0.4 to 0.6 in order to prevent diffuse reflection on the non-uniform metal layer 13. Can be. In this case, when the absorption coefficient of the first photoresist 25 is less than 0.4, the absorption coefficient of the diffuse reflection prevention film of the semiconductor device may not be reached, and thus, the nonuniform metal layer 13 formed below the first photoresist 25. It may be difficult to fully planarize. In addition, when it is 0.6 or more, since it becomes higher than the absorption coefficient of an anti-reflective film, reflection light does not reach the bottom part of the 1st photoresist 25, and not only the 1st photoresist 25 remains but also patterning at the time of a patterning process This can be difficult. The first photoresist 25 changes the energy absorption coefficients of the resin and the photo active compound (PAC) in the knoblock resin, the photosensitive agent, the solvent, the poly hydroxy strene (PHS) system, and the like, respectively, thereby reducing the absorption coefficient by 0.4. To 0.6. Accordingly, the absorption coefficient of the first photoresist 25 may be equal to or larger than the absorption coefficient of the diffuse reflection prevention film of the semiconductor device. Here, by further coating the second photoresist 26 having an absorption coefficient of 0.1 to 0.3 on the first photoresist 25, the planarization characteristic may be further improved.

The second photoresist 26 has an absorption coefficient of 0.1 to 0.3 and may be formed of any one selected from a knoblock-based resin, a photosensitive agent, a solvent, a poly hydroxy strene (PHS) system, and the like, but the material is not limited thereto. . In addition, the second photoresist 26 may be formed on the first photoresist 25 by any one method selected from among spin coating, roller coating, and an equivalent method. no.

As described above, double coating is performed on the metal layer 13 with the first photoresist 25 having an absorption coefficient of 0.4 to 0.6 and the second photoresist 26 having an absorption coefficient of 0.1 to 0.3. The flattening characteristic for flattening 13) is improved more and at the same time, the diffuse reflection can be reduced more stably, thereby eliminating the defect of the pattern.

Next, as shown in FIG. 4D, in the metal layer etching step S4, the metal layer 13 is etched using the first photoresist 25 and the second photoresist 26 as a mask. The metal layer 13 may be etched by using a dry etching method or a wet etching method.

Lastly, as shown in FIG. 4E, in the photoresist removing step S5, the first photoresist 25 and the second photoresist 26 stacked on the metal layer 13 are simultaneously removed. The first photoresist 25 and the second photoresist 26 may be removed by any one selected from a sulfuric acid solution, a plasma, and an equivalent thereof, but are not limited thereto.

Referring to FIG. 1, a flowchart of a method of forming a metal pattern of a semiconductor device according to an embodiment of the present invention is shown.

2A through 2E, cross-sectional views illustrating a method of forming a metal pattern of a semiconductor device according to an exemplary embodiment of the present invention illustrated in FIG. 1 are illustrated.

Referring to FIG. 3, a flowchart of a method of forming a metal pattern of a semiconductor device according to another embodiment of the present invention is shown.

4A through 4E, cross-sectional views illustrating a method of forming a metal pattern of a semiconductor device according to another exemplary embodiment of the present invention shown in FIG. 1 are illustrated.

Claims (4)

A metal layer forming step of forming a metal layer on the semiconductor substrate; A photoresist coating step of coating a photoresist having an absorption coefficient of 0.4 to 0.6 on the metal layer; A photoresist patterning step of patterning the photoresist by exposing and developing the photoresist; A metal layer etching step of etching the metal layer; And And a photoresist removing step of removing the photoresist. A metal layer forming step of forming a metal layer on the semiconductor substrate; A first photoresist coating step of coating a first photoresist having an absorption coefficient of 0.4 to 0.6 on the metal layer; A second photoresist coating step of coating a second photoresist on the first photoresist; A photoresist patterning step of patterning the first photoresist and the second photoresist by exposure and development; A metal layer etching step of etching the metal layer; And And removing a photoresist for removing the first photoresist and the second photoresist. The method of claim 2, And the absorption coefficient of the second photoresist is lower than that of the first photoresist. The method of claim 2, The second photoresist is Method for forming a metal pattern of a semiconductor device, characterized in that the absorption coefficient is made of 0.1 to 0.3.

Images