JP2809274B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device for forming a fine wiring having a resolution equal to or less than a resolution of a photoresist on a semiconductor substrate.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing a semiconductor device using a photoresist of this type, there is a method performed according to a manufacturing process as shown in FIGS. 3A and 3B.

First, as shown in FIG. 3A, a photoresist 4 is patterned on a conductive film 2 having a laminated structure of a barrier metal such as aluminum and titanium provided on a semiconductor substrate 1 as one step. Then, the conductive film 2 is etched to form a wiring. Here, the resolution limit of the photoresist 4 is the minimum width of the wiring. For example, 0.
When etching the conductive film 2 having a thickness of 8 μm, about 2 μm
The minimum width of the wiring is about 0.6 μm in the photoresist 4 having a thickness of m.

[0004] When the thickness of the photoresist 4 is reduced, the resolution is improved and patterning of 0.6 μm or less is possible. However, in the case of the conductive film 2 having a thickness of 0.8 μm, the thickness of the photoresist 4 is reduced. When the thickness of the conductive film 2 is set to 2 μm or less, the photoresist 4 is etched together with the material of the conductive film 2 when the conductive film 2 is etched, and the film thickness is reduced. Therefore, the photoresist 4 is lost before the etching of the conductive film 2 is completed. As a result, the wiring becomes thinner or thinner.

Next, as shown in FIG. 3 (b), after removing the photoresist 4 to grow the insulating film 3 as another process, the insulating film 3 is polished to a desired thickness to obtain a semiconductor device. The main part has been obtained.

Incidentally, as another known technique related to the technique of manufacturing a semiconductor device using such a photoresist, there is, for example, a method of manufacturing a semiconductor device disclosed in Japanese Patent Application Laid-Open No. 4-155927.

[0007]

In the above-described method of manufacturing a semiconductor device, the thickness of the conductive film is about 0.5 to 0.5 in one step.
When the thickness is 1.0 [μm], the thickness of the photoresist is required to be about 1.5 to 2 [μm] in order to etch the conductive film. Is about 0.6 μm, it is difficult to reduce the inter-wiring capacitance in an integrated circuit of a semiconductor device requiring a wiring width of 0.6 μm or less, which is the resolution limit. There is a problem that the semiconductor device cannot be manufactured.

In the case of an integrated circuit of an existing semiconductor device, if the wiring capacitance is large and wiring delay is large, or if the influence of crosstalk between adjacent wirings becomes a problem, the mask of the wiring pattern needs to be recreated. There is also a problem that must be done.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a technical problem thereof is to manufacture a semiconductor device capable of easily forming fine wirings having a resolution equal to or less than the resolution limit of a photoresist and forming the same with high precision. It is to provide a method.

[0010]

According to the present invention, a conductive film and a photoresist are sequentially formed on a semiconductor substrate, the photoresist is exposed and patterned using a mask, and then the conductive film is etched. A wiring pattern forming step of patterning the wiring as a wiring, an insulating film forming step of growing an insulating film on the entire surface of the patterned semiconductor substrate after removing the photoresist, and forming the insulating film until the surface of the wiring comes out. A polishing step of polishing, after forming a photoresist on the entire surface of the polished semiconductor substrate, a patterning step of exposing and patterning a wiring pattern using a mask by offsetting a desired wiring width,
A method of manufacturing a semiconductor device including an etching step of etching and miniaturizing a wiring.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a semiconductor device according to the present invention will be described below in detail with reference to the drawings.

First, an outline of a method of manufacturing a semiconductor device according to the present invention will be briefly described. The method of manufacturing the semiconductor device is as follows.
A conductive pattern and a photoresist are sequentially formed on a semiconductor substrate, and the photoresist is exposed and patterned using a mask, and then, the conductive film is etched to form a pattern as a wiring. An insulating film forming step of growing the insulating film after removing the photoresist on the entire surface of the semiconductor substrate, a polishing step of polishing the insulating film until the surface of the wiring is exposed, and a photoresist on the entire surface of the polished semiconductor substrate After forming a pattern, a patterning step of exposing and patterning a wiring pattern with a desired wiring width offset by using a mask, and an etching step of etching and miniaturizing the wiring are performed. .

By the way, if the patterning step and the etching step here are repeated a plurality of times, a semiconductor device having a thinned wiring can be manufactured more easily and can be manufactured with high precision.

FIGS. 1A to 1E show a state change of a main part of a semiconductor device in a manufacturing process in order to explain a method of manufacturing a semiconductor device according to an embodiment of the present invention. is there. Here, FIG. 1A is a side sectional view showing a completed state, and is a sectional view taken along line AA of a local plan view shown in FIG.

The manufacturing process will be described in order. First, as a wiring pattern forming process, 0.5 μm thick aluminum, aluminum and T are deposited on the semiconductor substrate 1.
After a conductive film 2 of a laminated film of i, TiN or the like is formed by sputtering, a photoresist 4 is formed on the conductive film 2 by patterning so as to have a line width of 0.6 μm and a thickness of 1.5 μm. Thereafter, the conductive film 2 is etched to pattern the wiring in a state as shown in FIG. 1B.

Next, as a step of forming an insulating film, after removing the photoresist 4, an insulating film 3 of a 0.7 μm thick plasma oxide film is grown on the entire surface of the semiconductor substrate 1 on which the pattern is formed. As a polishing step, polishing is performed until the surface of the wiring by the conductive film 2 comes out, so that FIG.
State.

Furthermore, after a photoresist 5 is formed on the entire surface of the polished semiconductor substrate 1 as a patterning step, a wiring pattern of the conductive film 2 is formed by using a mask with an exposure device for a wiring width of 0.3 μm. Exposure is performed by using an exposure device with an offset, and patterning is performed. Subsequently, as a step of etching, the wiring made of the conductive film 2 is etched and miniaturized to obtain a state as shown in FIG. 1D. Here, the position of the photoresist pattern 5 with respect to the conductive film 2 (the pattern of the wiring) is not affected by the underlying step because the surface of the substrate when the exposure is performed by inputting the offset amount to the exposure apparatus is flattened by polishing. The alignment accuracy is higher.

Finally, when the insulating film 3 is grown and polished until the step of the conductive film 2 becomes flat, FIGS.
As shown in (e), a state is obtained in which the wiring is formed by the finely-divided conductive film 2 having a wiring width of 0.3 μm. FIG.
The hatched portion in (e) indicates the remaining portion of the conductive film 2 after the etching.

FIGS. 2 (a) to 2 (e) show a state change of a main part of a semiconductor device in a manufacturing process step by step to explain a method of manufacturing a semiconductor device according to another embodiment of the present invention. It is. However, FIG. 2A is also a side sectional view showing a completed state.

The manufacturing process will be described in order. First, as a wiring pattern forming process, 0.5 μm thick aluminum, aluminum and T
After a conductive film 2 of a laminated film of i, TiN or the like is formed by sputtering, a photoresist 4 is formed on the conductive film 2 by patterning so as to have a line width of 0.6 μm and a thickness of 1.5 μm. Thereafter, the conductive film 2 is etched to pattern the wiring in a state as shown in FIG. 2B.

Next, as a step of forming an insulating film, after removing the photoresist 4, an insulating film 3 of a 0.7 μm-thick plasma oxide film is grown on the entire surface of the semiconductor substrate 1 on which the pattern is formed. As a polishing step, polishing is performed until the surface of the wiring by the conductive film 2 comes out, so that FIG.
State. The process up to this point is
This is similar to the case of the above-described embodiment.

Further, in the patterning step, the wiring pattern of the conductive film 2 on the polished semiconductor substrate 1 is offset in one direction by 0.15 μm wiring width by a light exposure device using a mask by a light exposure device. Exposure and patterning, followed by etching of the wiring by the conductive film 2 as an etching step to make it finer,
The state as shown in FIG.

In addition, as a patterning step again, the wiring pattern of the conductive film 2 on the semiconductor substrate 1 polished as the patterning step is offset in the reverse direction by a width of 0.15 μm using a mask with an exposure apparatus using a mask. When the photoresist 6 is exposed and patterned by the exposure device as described above, and then the wiring of the conductive film 2 is etched again as an etching step, a state as shown in FIG. 2E is obtained.

Finally, when the insulating film 3 is grown and polished until the step of the conductive film 2 becomes flat, the conductive film 2 having a wiring width of 0.3 μm as shown in FIG. A state having wiring is obtained.

In this embodiment, since the conductive film 2 is miniaturized by etching both sides of the conductive film 2, the completed wiring pattern does not offset with respect to the design pattern. On the other hand, in the case of the first embodiment, it is necessary to design in consideration of the offset amount of the finished pattern with respect to the design pattern. A pattern (that is, a wiring pattern) can be easily designed.

[0026]

As described above, according to the method of manufacturing a semiconductor device of the present invention, an insulating film is grown after a wiring of a conductive film is formed on a semiconductor substrate, and is planarized by polishing. By again offsetting the first conductive film and etching the conductive film, it is possible to form fine wiring below the resolution limit of the photoresist,
For example, since a fine wiring of 0.3 μm can be formed, as a result, if the mask pattern has the same wiring interval as that of the related art, the wiring can be formed thinner, so that the capacitance between wirings can be reduced and the integration of the semiconductor device can be reduced. The speed of the circuit can be increased. Further, if the present invention is applied to the formation of an existing wiring pattern, the wiring can be miniaturized without recreating a wiring pattern mask, thereby reducing the capacitance between wirings and reducing the influence of crosstalk.

[Brief description of the drawings]

FIGS. 1A and 1B show a state change of a main portion of a semiconductor device in a manufacturing process in order to explain a method of manufacturing a semiconductor device according to an embodiment of the present invention, and FIG. (B) relates to a side cross-sectional view after forming a wiring pattern, (c) relates to a side cross-sectional view in a state where the wiring surface is polished after an insulating film is formed, and (d) relates to a first wiring pattern. It relates to a side sectional view in a state where the pattern is offset and etched, and (e) relates to a local plan view in a completed state.

FIGS. 2A and 2B show a state change of a main part of a semiconductor device in a manufacturing process in order to explain a method of manufacturing a semiconductor device according to another embodiment of the present invention, wherein FIG. (B) relates to a side sectional view after forming a wiring pattern, (c) relates to a side sectional view in which the wiring surface is polished after an insulating film is formed, and (d) relates to a wiring pattern first. (E) is a side sectional view of a state where the pattern of (1) is etched with an offset in one direction, and (e) is a state where the first wiring pattern is etched with an offset in the opposite direction to that of (d) FIG.

3A and 3B are views for explaining a conventional semiconductor device manufacturing process, in which FIG. 3A is a side sectional view of a main part of the semiconductor device in one step, and FIG. 3B is a main part of the semiconductor device in another step. FIG.

[Description of Signs] 1 semiconductor substrate 2 conductive film 3 insulating film 4, 5, 6 photoresist

Claims (1)

(57) [Claims] A wiring pattern is formed by sequentially forming a conductive film and a photoresist on a semiconductor substrate, exposing the photoresist using a mask, patterning the photoresist, and etching the conductive film to form a pattern as a wiring. Process and
An insulating film forming step of growing an insulating film on the entire surface of the patterned semiconductor substrate after removing the photoresist; a polishing step of polishing the insulating film until the surface of the wiring comes out; Forming a photoresist on the entire surface of the semiconductor substrate, and performing patterning by exposing and patterning the wiring pattern by offsetting a desired wiring width using the mask; and etching the wiring. A method of manufacturing a semiconductor device, the method comprising: