TW201727743A - Method for improving etch loading effect - Google Patents

Abstract

A method for improving etch loading effect including following steps is provided. A material layer is formed on a substrate, wherein the wafer has a center region and an edge region. A mask layer is formed on the material layer, wherein a thickness of the mask layer in the edge region is larger than a thickness of the mask layer in the center region. The mask layer is patterned to form a patterned mask layer having mask patterns, wherein a critical dimension of the mask pattern in the edge region is larger than a critical dimension of the mask pattern in the center region. The material layer is etched to form a patterned material layer by using the patterned mask layer as a mask.

Description

Improved method of etching load effect

SUMMARY OF THE INVENTION The present invention is directed to an improved method of semiconductor fabrication, and more particularly to an improved method of etch loading effect.

The integrated circuit industry is one of the most important industries in China. The application of integrated circuits has entered the various consumer fields in life from computer-related fields, thus making the integrated circuit industry flourish.

With the increasing complexity of integrated circuit technology and design, there are some problems to be solved in the integrated circuit process. When the etching process of the material layer to be patterned on the wafer is performed, the etching rate in the edge region of the wafer is higher than the etching rate in the central region of the wafer due to the etching load effect, and thus is formed in the edge region. The critical dimensions of the pattern are small, resulting in poor critical dimension uniformity (CDU).

A method using a dose mapper (DoseMapper) has been developed to control all processes in the patterning process by wafer information collection, simulation analysis and setting to solve the problem of etching load effect. However, the method of using the dose mapper has a problem of time consuming and high cost.

The present invention provides an improved method of etch loading effects that can increase critical dimension uniformity after etching by a fast, simple, and low cost method.

The present invention provides an improved method of etching load effects, including the following steps. A layer of material is formed on the wafer, wherein the wafer has a central region and an edge region. A mask layer is formed on the layer of material, wherein the thickness of the mask layer in the edge region is greater than the thickness in the central region. The mask layer is patterned to form a patterned mask layer having a plurality of mask patterns, wherein the critical dimension of the mask pattern in the edge regions is greater than the critical dimension of the mask pattern in the central region. The patterned material layer is formed by etching the material layer with the patterned mask layer as a mask.

According to an embodiment of the present invention, in the above method for improving the etching load effect, the mask layer may be a single layer structure or a multilayer structure.

According to an embodiment of the present invention, in a method for improving an etch load effect, the mask layer may include at least one of a photoresist layer, a germanium mask layer, and an organic dielectric layer (ODL). By.

According to an embodiment of the present invention, in the method for improving the etching load effect, the material of the photoresist layer is, for example, a positive photoresist material or a negative photoresist material.

According to an embodiment of the present invention, in the above method for improving the etching load effect, the germanium-containing mask layer is, for example, a silicon-containing ARC layer.

According to an embodiment of the present invention, the material of the organic dielectric layer is, for example, a photo-sensitive organic polymer or an etch type organic compound. ).

According to an embodiment of the present invention, in the method for improving the etching load effect, the critical dimension of the photoresist layer after the lithography process can be controlled according to the swing curve characteristic of the photoresist layer.

According to an embodiment of the present invention, in the above method for improving the etching load effect, the method of forming the mask layer may include the following steps. A first spin coating process is performed to apply the first mask material to the material layer in a comprehensive manner. A second spin coating process is performed to apply only the second mask material to the first mask material of the edge region.

According to an embodiment of the present invention, in the above method for improving the etching load effect, the first mask material and the second mask material may have the same or different viscosity coefficients.

According to an embodiment of the present invention, in the above method for improving the etching load effect, the second spin coating process performs, for example, spraying of the second mask material in the edge region.

Based on the above, in the improved etching load effect method proposed by the present invention, since the thickness of the mask layer in the edge region is greater than the thickness in the central region, the mask formed in the edge region is formed by the patterned mask layer. The critical dimension of the curtain pattern is larger than the critical dimension of the mask pattern in the central zone. Therefore, when the material layer is etched by using the patterned mask layer as a mask, the critical dimension of the mask pattern in the edge region by patterning the mask layer is larger than the critical dimension of the mask pattern in the central region. The characteristics of the etch load can be effectively improved, so that the pattern of the patterned material layer can have substantially the same critical dimensions in the edge region and the central region. Based on the above, the improved etching load effect method proposed by the present invention can improve the critical size uniformity after etching by a fast, simple, and low-cost method.

The above described features and advantages of the invention will be apparent from the following description.

FIG. 1 is a flow chart showing a method for improving an etch load effect according to an embodiment of the present invention. 2A-2B are flow diagrams showing the coating of the mask layer according to an embodiment of the invention. FIG. 3 is a schematic diagram showing a swing curve of a photoresist layer.

Referring to FIG. 1, step S100 is performed to form a material layer on the wafer, wherein the wafer has a central region and an edge region. The material layer can be any layer or substrate of material to be etched. The material of the material layer is, for example, a conductor material (e.g., metal or the like), a semiconductor material, or a dielectric material.

Step S110 is performed to form a mask layer on the material layer, wherein the thickness of the mask layer in the edge region is greater than the thickness in the central region. The mask layer can be a single layer structure or a multilayer structure. The mask layer can include at least one of a photoresist layer, a germanium-containing mask layer, and an organic dielectric layer. The material of the photoresist layer is, for example, a positive photoresist material or a negative photoresist material. The ruthenium-containing mask layer is, for example, a ruthenium-containing antireflection coating such as Sepr-Shb Aseries SiARC (product name) manufactured by Shin Etsu Chemical Co., Ltd. The material of the organic dielectric layer is, for example, a photosensitive organic polymer or an etched organic compound. For example, the photosensitive organic polymer may be a polyacrylate resin, an epoxy resin, a phenol resin, a polyamide resin, or a polyimide resin ( Polyimide resin), unsaturated polyester resin, polyphenylenether resin, polyphenylene sulfide resin or benzocyclobutene (BCB).

The method of forming the mask layer may include the following steps, but the invention is not limited thereto. Step S112 is performed to perform a first spin coating process to uniformly coat the first mask material on the material layer.

For example, referring to FIG. 2A, the first spin coating process is, for example, disposing the wafer W on the turntable 100, and then spraying the first mask material 104a in the central region R1 of the wafer W by the nozzle 102, and The first mask material 104a is uniformly applied to the central region R1 and the edge region R2 of the wafer W by the rotation of the turntable 100.

Referring to FIG. 1, step S114 is performed to perform a second spin coating process, and only the second mask material is coated on the first mask material of the edge region. The first mask material and the second mask material are, for example, the same mask material. The first mask material and the second mask material may have the same or different viscosity coefficients, so that the mask layer may be controlled in the central region and the edge region by adjusting the viscosity coefficient of the first mask material and the second mask material. Film thickness. The second spin coating process, for example, is to spray the second mask material in the edge region. Further, the first spin coating process and the second spin coating process may be performed continuously or in two stages.

For example, referring to FIG. 2B, the second spin coating process moves, for example, the nozzle 102 into the edge region R2, and then sprays the first mask material 104a in the edge region R2 of the wafer W by the nozzle 102. The second mask material 104b, and the second mask material 104b is uniformly applied to the edge region R2 of the wafer W by the rotation of the turntable 100. Thus, the mask layer 104 can be formed by the first mask material 104a and the second mask material 104b, and the thickness of the mask layer 104 in the edge region R2 is greater than the thickness in the central region R1.

In this embodiment, the mask layer is described by a three-layer structure including an organic dielectric layer, a germanium mask layer and a photoresist layer which are sequentially stacked on the material layer, but the present invention does not Limits, those skilled in the art can select the number and type of the mask layer according to the process requirements. In addition, when the thickness of any one of the organic dielectric layer, the germanium-containing mask layer and the photoresist layer in the edge region is to be adjusted to be larger than the thickness in the central region, the above steps S112 and S114 may be selected. An example method.

Referring to FIG. 1, step S120 is performed to pattern the mask layer to form a patterned mask layer having a plurality of mask patterns, wherein the mask pattern in the edge region has a larger critical dimension than the mask in the central region. The key dimensions of the curtain pattern. Further, since the thickness of the mask layer in the edge region is greater than the thickness in the central region, after the mask layer is patterned, the critical dimension of the mask pattern formed in the edge region is greater than that in the central region. The key dimensions of the mask pattern formed in the film.

For the photoresist layer, the critical dimension of the photoresist layer after the lithography process can be controlled according to the rocking curve characteristic of the photoresist layer. Referring to FIG. 3, the shape of the rocking curve of the photoresist layer may be similar to the sinusoid of the trend upward. Overall, the thickness of the photoresist layer is proportional to the critical dimension of the photoresist pattern formed after the lithography process. That is, the thicker the thickness of the photoresist layer, the larger the critical dimension of the photoresist pattern. For example, the critical dimension of the photoresist pattern of peak A2 is greater than the critical dimension of the photoresist pattern of peak A1.

In the rocking curve of the photoresist layer, the thicker the thickness of the photoresist layer is, the smaller the critical dimension of the photoresist pattern is, between the cells between the wave front A1 and the valley B. Further, as for the inter-cell between the valley B and the wave front A2, the thicker the thickness of the photoresist layer, the larger the critical dimension of the photoresist pattern. Therefore, after determining the thickness level of the photoresist layer, the critical dimensions of the photoresist pattern can be fine-tuned by the above-described rocking curve characteristics.

For the organic dielectric layer, the thickness of the organic dielectric layer is proportional to the critical dimension of the organic dielectric pattern formed after the etching process. That is, the thicker the thickness of the organic dielectric layer, the larger the critical dimension of the organic dielectric pattern. In addition, the same is true for the enamel-containing curtain layer. That is, the thickness of the ruthenium-containing mask layer is proportional to the critical dimension of the ruthenium-containing mask pattern formed after the etching process.

Referring to FIG. 1, step S130 is performed to pattern the mask layer as a mask to etch the material layer to form a patterned material layer. In general, the etch rate of the edge region is higher than the etch rate of the central region when the material layer is etched under the influence of the etch load effect. However, since the critical dimension of the mask pattern in the edge region of the patterned mask layer of the present embodiment is larger than the critical dimension of the mask pattern in the central region, the effect of the etch load effect can be compensated for, thereby The pattern of patterned layer of material may have substantially the same critical dimensions in the edge region and the central region.

In addition, in this embodiment, since the mask layer is described by a three-layer structure including an organic dielectric layer, a ruthenium mask layer, and a photoresist layer which are sequentially stacked on the material layer, it is possible to The thickness distribution of the resist layer is mainly adjusted for the critical dimension of the patterned material layer, and the critical dimension of the patterned material layer can be achieved by the thickness distribution of the organic dielectric layer and/or the thickness distribution of the germanium-containing mask layer. Fine adjustment is made, but the invention is not limited thereto. Those skilled in the art can refer to the content of the above embodiments and select the adjustment method of the key dimensions of the patterned material layer according to the process requirements.

Based on the above embodiments, since the thickness of the mask layer in the edge region is greater than the thickness in the central region, the formed mask layer has a larger critical dimension of the mask pattern in the edge region than in the central region. The key dimensions of the mask pattern. Therefore, when the material layer is etched by using the patterned mask layer as a mask, the critical dimension of the mask pattern in the edge region by patterning the mask layer is larger than the critical dimension of the mask pattern in the central region. The characteristics of the etch load can be effectively improved, so that the pattern of the patterned material layer can have substantially the same critical dimensions in the edge region and the central region. Based on the above, the method of improving the etching load effect of the above embodiment can improve the critical size uniformity after etching by a fast, simple, and low-cost method.

In summary, in the method for improving the etching load effect of the above embodiment, since the critical dimension of the patterned material layer is adjusted by the thickness distribution of the mask layer, it can be quickly, easily and in a low cost manner. To increase the critical size uniformity after etching.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧ Turntable
102‧‧‧Nozzles
104‧‧‧ Cover layer
104a‧‧‧First curtain material
104b‧‧‧Second curtain material
A1, A2‧‧‧ crest
B‧‧‧Valley
R1‧‧‧Central District
R2‧‧‧ Marginal Area
S100, S110, S112, S114, S120, S130‧‧‧ steps

FIG. 1 is a flow chart showing a method for improving an etch load effect according to an embodiment of the present invention. 2A-2B are flow diagrams showing the coating of the mask layer according to an embodiment of the invention. FIG. 3 is a schematic diagram showing a swing curve of a photoresist layer.

S100, S110, S112, S114, S120, S130‧‧‧ steps

Claims (10)

An improved method of etching load effect, comprising: forming a material layer on a wafer, wherein the wafer has a central region and an edge region; forming a mask layer on the material layer, wherein the mask layer is a thickness in the edge region is greater than a thickness in the central region; patterning the mask layer to form a patterned mask layer having a plurality of mask patterns, wherein the mask in the edge region The critical dimension of the curtain pattern is greater than the critical dimension of the mask pattern in the central region; and the patterned layer is etched using the patterned mask layer as a mask to form a layer of patterned material. The method of improving the etching load effect of claim 1, wherein the mask layer is a single layer structure or a multilayer structure. The method of improving the etch load effect of claim 1, wherein the mask layer comprises at least one of a photoresist layer, a germanium-containing mask layer, and an organic dielectric layer. The method for improving the etching load effect according to claim 3, wherein the material of the photoresist layer comprises a positive photoresist material or a negative photoresist material. The method of improving the etch load effect of claim 3, wherein the ruthenium-containing mask layer comprises a ruthenium-containing anti-reflective coating. The method of improving the etching load effect of claim 3, wherein the material of the organic dielectric layer comprises a photosensitive organic polymer or an etched organic compound. The method for improving the etching load effect according to claim 3, wherein the critical dimension of the photoresist layer after the lithography process is controlled according to a rocking curve characteristic of the photoresist layer. The method for improving an etch load effect according to claim 1, wherein the method for forming the mask layer comprises: performing a first spin coating process, and applying the first mask material to the whole And performing a second spin coating process to coat only the second mask material on the first mask material of the edge region. The method of improving the etch load effect of claim 8, wherein the first mask material and the second mask material have the same or different viscosity coefficients. The method of improving the etch load effect of claim 8, wherein the second spin coating process performs spraying of the second mask material in the edge region.