JPH07321225A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve the method of forming a stacked capacitor of a fine pattern DRAM, a wiring layer, etc. CONSTITUTION:This manufacture comprises a step of selectively forming a resist film 13 on a layer 12 where a pattern is formed, a step of heat-treating the resist film 13 and forming a flow resist film 13A which is expanded circularly in cross section, and a process of etching off the layer 13, where a pattern is formed, with the flow resist film 13A as a mask, thereby forming a pattern 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more specifically, an object of the invention is to improve a method for forming a stacked capacitor or a wiring layer of a miniaturized DRAM.

[0002]

2. Description of the Related Art A conventional method of manufacturing a semiconductor device will be described below with reference to the drawings. A conventional method of manufacturing a semiconductor device is a method of forming a stacked capacitor used in a DRAM or the like. First, as shown in FIG. 7, a polysilicon layer (2) is formed on a silicon substrate (1A) having an oxide film (1B) formed on its surface, a photoresist is applied thereon, and exposed by a stepper. After that, development and patterning are performed, and a plurality of resist films (3) having a line width (a) are selectively formed at intervals (b).

Next, as shown in FIG. 8, a resist film (3)
With the mask as a mask, the polysilicon layer (2) is etched and removed by RIE (Reactive Ion Etching) and patterned. Next, as shown in FIG. 9, the resist film (3) is peeled off with a peeling solution or the like to expose the electrode layer (4), thereby forming an electrode layer (4) made of polysilicon, and not shown thereon. The stacked capacitor was formed by sequentially forming the insulating film and the counter electrode (not shown).

Since the capacity of the stacked capacitor depends on the upper area of the electrode layer (4), the interval between the electrode layers (4) is narrowed to secure the electrode area as large as possible and the capacitance as large as possible. There was a request to do so.

[0005]

However, according to the above conventional method, the interval (b) between the resist films (3) is
No matter how miniaturization progresses, the resolution performance of the stepper at the time of exposing the photoresist film is at most the limit, and the distance between the electrode layers (4) formed by etching using the mask as a mask is further increased. It was not possible to narrow the width and secure a large upper area of the electrode layer (4).

[0006]

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and includes a step of selectively forming a resist film (13) on a pattern forming layer (12), and the resist film (13). ) Is heat-treated to flow to form a flow resist film (13A) whose cross section is expanded in a circular shape,
By forming the pattern (14) by etching / removing the patterned layer (12) using the flow resist film (13A) as a mask, the formation interval becomes narrower than the resolution performance of the stepper, and the upper area is increased. The present invention provides a method for manufacturing a semiconductor device, which makes it possible to form a large pattern.

[0007]

[Operation] According to the method of manufacturing a semiconductor device of the present invention, as shown in FIG. 1, after the resist film (13) is selectively formed on the pattern formation layer (12), as shown in FIG. The resist film (13) is heat-treated and allowed to flow to form a flow resist film (13A) whose cross section is expanded in a circular shape.

Therefore, since the flow resist film (13A) whose cross section is expanded in a circular shape is formed, the line width is widened by the expanded amount. Therefore, the flow resist film (13A) is used as a mask to form a base. Pattern forming layer (1
When the pattern (14) is formed by etching and removing 2), the upper area of the pattern (14) is increased and the adjacent pattern (14) is increased as compared with the case where the resist film (13) is directly used as a mask. ) Can be narrowed.

As a result, for example, it becomes possible to form a stacked capacitor having a larger capacitance than the conventional one, or to form a wiring layer having a narrower formation interval than the conventional one.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a semiconductor device according to an embodiment of the present invention will be described below with reference to the drawings. First,
As shown in FIG. 1, a polysilicon layer (12) is formed on a silicon substrate (10) on which an oxide film (11) is formed, a photoresist is applied on the polysilicon layer (12), and after exposure by a stepper, By developing and patterning, a plurality of resist films (13) having a line width (a) are selectively formed at intervals (b).

Next, as shown in FIG.
At a temperature of 0 ° C, preferably about 180 ° C, the resist film (1
3) is flowed to form a flow resist film (13A) having a circular cross section as shown in FIG. The flow resist film (13A) flows and is softened, and then the cross-sectional shape thereof expands into a circular shape due to surface tension, and thereafter solidifies as it is. As described above, the flow resist film (13A) is increased by an increment (Δa) in comparison with the original line width (a) and is adjacent to the flow resist film (13A).
(C) is narrower than the interval (b) of the resist film (13) before flowing.

Next, as shown in FIG. 3, the underlying polysilicon layer (12) is patterned by etching / removing it by dry etching such as RIE using the flow resist film (13A) as a mask to form the first electrode. Form the layer (14). At this time, as described above, the line width (a + Δ) of the flow resist film (13A) serving as a mask is obtained.
Since a) is larger than the line width (a) before flowing and the mutual interval (c) is narrower than the interval (c) before flowing, patterning is performed using this as a mask. The line width (a +) of the first electrode layer (14) formed by
As shown in FIG. 3, Δa) is also wider than in the conventional case, the upper area is increasing, and the mutual interval (c) is narrowing.

Next, as shown in FIG. 4, the flow resist film (13A) is stripped with a stripping solution or the like to remove the first electrode layer (1).
After exposing 4), the insulating film (1
5), a second electrode layer (16) made of a polysilicon layer is selectively formed on the first electrode layer (14), so that the stacked electrode used in the DRAM as shown in FIG.
Form a capacitor (17).

As described above, according to the semiconductor device manufacturing method of this embodiment, the flow resist film (the width of which (a + Δa) is expanded by Δa) is expanded by Δa as compared with the conventional one. 13A) is used as a mask to etch and remove the underlying polysilicon layer (12) to form the first and second electrode layers (12, 16). Compared with the case where the resist film (13) is used as it is as a mask, the first and second electrode layers (12,
The line width of 16) is increased by the increment (Δa) to increase the area above the line width of the adjacent first and second electrode layers (1
2, 16) can be narrowed.

As a result, the stacked capacitor (1
By increasing the electrode area of 7), it becomes possible to form a stacked capacitor having a larger capacitance than the conventional one. The graph shown in FIG. 6 is a graph for explaining the function and effect of the present invention, and is an experiment in which the resist film (13) is heat-treated at a temperature of about 180 ° C. to flow to form the flow resist film (13A). It is a graph which shows the result of. In this graph, the horizontal axis represents the line width dimension (a) of the resist film (13) before heat treatment, and the vertical axis represents the line width dimension (a) of the resist film (13) before heat treatment and the heat flow. The dimension increment (Δa) which is the difference from the maximum line width dimension (a + Δa) of the flow resist film (13A) as shown in FIGS. 2 and 3 is shown.

As shown in the above graph, when the original dimension (a) is about 1 μm, the dimension increment (Δa) is 0.
It can be seen that the maximum is about 2 μm. Accordingly, when resist films having a line width of about 1 μm are formed at intervals of, for example, 0.6 μm, the line width dimension of each resist film after heat treatment is increased by 0.2 μm.
It was confirmed that each interval was reduced to 0.4 μm and the area of the resist film was increased accordingly. This difference is a non-negligible difference in the recent manufacturing technology of semiconductor devices miniaturized to the submicron level, and it can be seen that the present invention is effective.

In the present embodiment, the first electrode (14) of the stacked capacitor (17) is taken as an example of the pattern (14), but the present invention is not limited to this, and the first electrode (14) is not limited to this. The same effect is obtained when forming a wiring layer and the like, and a polysilicon layer is used as an example of the pattern formation layer (12), but the present invention is not limited to this, and a metal such as aluminum or the like, An insulating film such as an oxide film has the same effect.

[0018]

As described above, according to the method of manufacturing a semiconductor device of the present invention, after the resist film (13) is selectively formed on the pattern forming layer (12), the resist film (13) is heat-treated. Since the flow resist film (13A) whose cross section is expanded in a circular shape is formed, the underlying pattern forming layer (12) is etched and removed using this flow resist film (13A) as a mask. By forming the pattern (14), the line width and the upper area of the pattern (14) are increased as compared with the case where the non-flowing resist film (13) is used as a mask as it is, and the pattern (14) of the adjacent pattern (14) is formed. The space can be narrowed.

As a result, for example, it becomes possible to form a stacked capacitor having a larger capacitance than the conventional one, or to form a wiring layer having a narrower formation interval than the conventional one.

[Brief description of drawings]

FIG. 1 is a first cross-sectional view illustrating a method of manufacturing a semiconductor device according to an embodiment of the invention.

FIG. 2 is a second cross-sectional view illustrating the method for manufacturing the semiconductor device according to the embodiment of the invention.

FIG. 3 is a third cross-sectional view illustrating the method for manufacturing the semiconductor device according to the embodiment of the invention.

FIG. 4 is a fourth sectional view illustrating the method for manufacturing the semiconductor device according to the embodiment of the invention.

FIG. 5 is a fifth cross-sectional view illustrating the method for manufacturing the semiconductor device according to the embodiment of the invention.

FIG. 6 is a graph illustrating the effects of the method for manufacturing a semiconductor device according to the example of the present invention.

FIG. 7 is a first cross-sectional view explaining the method for manufacturing the first semiconductor device of the conventional example.

FIG. 8 is a second cross-sectional view explaining the method for manufacturing the first semiconductor device of the conventional example.

FIG. 9 is a third cross-sectional view explaining the method for manufacturing the first semiconductor device of the conventional example.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H01L 21/3065 21/768 H01L 21/302 H 21/90 D

Claims (4)

[Claims] 1. A step of selectively forming a resist film (13) on a layer (12) to be patterned, and a flow resist film (wherein the resist film (13) is heat-treated to flow and expands in a circular cross section ( 13A) and a step of forming the pattern (14) by etching and removing the patterned layer (12) using the flow resist film (13A) as a mask. Device manufacturing method. 2. A step of selectively forming a resist film (13) on a patterned layer (12), and a step of heat-treating the resist film (13) at a temperature of about 180 ° C. or more and 200 ° C. or less to flow the cross section. Forming a flow resist film (13A) that expands in a circular shape, and etching and removing the patterned layer (12) using the flow resist film (13A) as a mask to form a pattern (14). A method of manufacturing a semiconductor device, comprising: 3. A step of selectively forming a resist film (13) on the polysilicon layer (12), and a step of heat-treating the resist film (13) at a temperature of about 180 ° C. or more and 200 ° C. or less to cause a flow, Forming a circularly expanded flow resist film (13A); and etching and removing the polysilicon layer (12) using the flow resist film (13A) as a mask to form the first electrode (14). An insulating film (15) and a second electrode (16) are sequentially formed on the first electrode (14) to form the first electrode (1).
4), a step of forming a stacked capacitor (14) including an insulating film (15) and a second electrode (16), and a method of manufacturing a semiconductor device. 4. A step of selectively forming a resist film (13) on the polysilicon layer (12), and a step of heat-treating the resist film (13) at a temperature of about 180 ° C. or more and 200 ° C. or less to cause a flow, A step of forming a circularly expanded flow resist film (13A), and a wiring layer (14) is formed by etching and removing the polysilicon layer (12) using the flow resist film (13A) as a mask. A method of manufacturing a semiconductor device, comprising: