JPH04221826A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To provide a semiconductor device manufacturing method by which highly accurate patterning can be easily performed even to a semiconductor substrate having a large level-difference and overhang sections. CONSTITUTION:A substrate having a large level-difference and overhang sections is flattened by burying spin-on-glass film 5 in the substrate 4. After a resist pattern 6 is formed on the flattened substrate 4, the resist pattern 6 is removed, and then, the remaining spin-on-glass film 5 is removed.

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.

0002

2. Description of the Related Art When forming a resist pattern on a substrate having a high level difference, there is a step of processing a deposited film having an overhang structure. 10 to 12 show schematic cross-sectional views of the steps in which the overhang structure is formed. A thermal oxide film 2 is formed on the surface of the substrate 1, and polycrystalline silicon 4 is further deposited on the thermal oxide film 2 (FIG. 10).

Next, after forming a resist (not shown) pattern, a predetermined portion of the polycrystalline silicon 4 is removed to obtain a vertical pattern of polycrystalline silicon 4 (FIG. 11). Next, a CVD oxide film 3 is deposited on the remaining polycrystalline silicon 4 and the thermal oxide film 2. In this case, a film with poor step coverage is deposited, resulting in an overhang structure. FIGS. 13 to 16 show schematic cross-sectional views of the conventional process of patterning a substrate having an overhang structure described above using a single-layer resist process, and a patterning process using a three-layer resist process. Schematic cross-sectional views of the forming process are shown in FIG. 13 and FIGS. 17 to 21. This will be explained below based on the drawings.

A thermal oxide film 2 is formed on the surface of the substrate 1, and a CVD oxide film 3 is further deposited on the thermal oxide film 2. After forming a resist (not shown) pattern on the CVD oxide film 3, a groove 11 is formed by removing a predetermined portion of the CVD oxide film 3. Thereafter, polycrystalline silicon 4 is deposited on the CVD oxide film 3 and in the trench 11 (FIG. 13). Next, a resist 6 is applied on the polycrystalline silicon 4 (
Figure 14). Thereafter, a mask pattern is formed and exposure is performed (FIG. 15). Next, the desired pattern is obtained by developing the substrate (FIG. 16).

On the other hand, in the step of forming a pattern using the three-layer process, a lower resist 7 is first applied on the substrate shown in FIG. 13, and then an intermediate layer 8 is formed on the lower resist 7. This intermediate layer 8 is made of, for example, coated glass. Next, an upper layer resist 9 is applied on the intermediate layer 8.
(Figure 17). Next, the upper resist pattern (
(not shown), and the upper resist layer 9 directly above the groove 11 is removed (FIG. 18). Thereafter, by dry developing the substrate, the intermediate layer 8 immediately below the removed upper resist layer 9 is removed.
(Figure 19).

Next, the lower resist layer 7 is removed by anisotropic etching (FIG. 20). Thereafter, polycrystalline silicon 4 is etched (FIG. 21).

[0007]

[Problems to be Solved by the Invention] As mentioned above, in the single-layer resist process, it is difficult to remove the resist in the thin slit shape as shown in FIG. 16 and process it to the desired line width. It is. In addition, in the three-layer process, when processing the lower resist layer, a method such as anisotropic dry development is used, so as shown in FIG. 20, it is difficult to remove the resist under the overhang, that is, the lower resist layer 7a. Further, as shown in FIG. 21, there is a problem in that polycrystalline silicon 4a is partially left over from the polycrystalline silicon.

The present invention has been made in view of these points, and it is an object of the present invention to provide a method for manufacturing a semiconductor device that facilitates the formation of a resist pattern on a high level difference and also facilitates the processing of an overhang shape. With the goal.

[0009]

[Means for Solving the Problems] A method for manufacturing a semiconductor device according to the present invention includes forming a thermal oxide film on a substrate, followed by CV
After forming the D oxide film, a groove is formed by removing a predetermined portion of the CVD oxide film, then polycrystalline silicon is deposited on the CVD oxide film and in the groove, and then polycrystalline silicon is deposited on the polycrystalline silicon. After coating the spin-on glass in the groove, a photoresist is formed on the spin-on glass that does not include the groove, and then the spin-on glass in the groove is removed by etching, and then the polycrystalline polycrystalline glass remaining in the groove is removed. After removing the silicon by etching, the photoresist is removed, and then the CVD
A feature of this method is that the spin-on glass remaining on the oxide film is removed.

0010

[Operation] Before forming the photoresist, the substrate is planarized by depositing spin-on glass on the substrate and on the groove portion having the overhang structure.

[0011]

Embodiments FIGS. 1 to 9 are schematic sectional views showing embodiments of the present invention over time. Embodiments of the present invention will be described below based on the drawings. A thermal oxide film 2 is formed on the surface of a substrate 1, and a CVD oxide film 3 is further deposited on the thermal oxide film 2. After forming a resist (not shown) pattern on the CVD oxide film 3, a predetermined portion of the CVD oxide film 3 is removed to form a trench 10 in the CVD oxide film 3. After that, polycrystalline silicon 4 is placed on the CVD oxide film 3 and in the trench 10.
(Figure 1).

[0012] Next, spin-on glass 5 (spin-on glass 5
Glass) and embed it (Figure 2). Thereafter, a photoresist 6 is formed on the spin-on glass 5 (FIG. 3). Next, the spin-on glass 5 is removed in a thin slit shape by anisotropic etching (FIG. 4), and the spin-on glass 5 in the groove 10 is further removed isotropically by isotropic etching (FIG. 5). . Next, polycrystalline silicon 4 is removed by anisotropic etching (FIG. 6), and polycrystalline silicon 4 in trench 10 is further removed isotropically by isotropic etching.

Next, the photoresist 6 is removed (FIG. 8),
The spin-on glass 5 remaining on the polycrystalline silicon 4 is
Remove with HF aqueous solution etc. (Figure 9). Through the above steps, the photoresist 6 under the overhang can be removed, and the polycrystalline silicon 4 will not remain in the groove 11.

[0014]

Effects of the Invention As explained above, according to the present invention, since planarization is performed before forming a photoresist pattern, the resist pattern can be formed even on a substrate having a high level difference or an overhang structure. This makes it easy to achieve highly accurate patterning. As a result, high integration can be easily achieved.

[Brief explanation of the drawing]

[Figure 1] Schematic cross-sectional diagram showing the embodiments of the present invention over time

[
Fig. 2 Schematic cross-sectional views showing examples of the present invention over time

[Figure 3] Schematic cross-sectional views showing examples of the present invention over time

[Figure 4
] Schematic sectional views showing examples of the present invention over time

[Figure 5]
Schematic sectional views showing examples of the present invention over time

[Figure 6]
Schematic sectional views showing examples of the present invention over time

[Figure 7]
Schematic sectional views showing examples of the present invention over time

[Fig. 8] Schematic cross-sectional views showing examples of the present invention over time

[Fig. 9] Schematic cross-sectional views showing examples of the present invention over time

[Figure 10] Schematic cross-sectional diagram showing the overhang structure formation process over time

[Figure 11] Schematic cross-sectional view showing the overhang structure formation process over time

[Figure 12] Schematic cross-sectional view showing the overhang structure formation process over time

[Figure 13] Schematic cross-sectional view showing the conventional example over time

[Figure 1
4] Schematic cross-sectional diagram showing the conventional example over time

[Figure 15]
Schematic cross-sectional diagram showing the conventional example over time

[Figure 16] Schematic cross-sectional diagram showing the conventional example over time

[Figure 17] Schematic sectional view showing another conventional example over time

[Figure 18] Schematic cross-sectional diagram showing another conventional example over time

[Figure 19] Schematic cross-sectional view showing another conventional example over time

[Figure 20] Schematic cross-sectional view showing another conventional example over time

[Figure 21] Schematic cross-sectional view showing another conventional example over time

[Explanation of symbols]

1... Single crystal silicon 2...Thermal oxide film 3...CVD oxide film 4... Polycrystalline silicon 5...Spin-on glass 6...Photoresist １０・・・Groove

Claims (1)

[Claims] Claim 1: A thermal oxide film is formed on a substrate, and then C
After forming a VD oxide film, a groove is formed by removing a predetermined portion of the CVD oxide film, then polycrystalline silicon is deposited on the CVD oxide film and in the groove, and then polycrystalline silicon is deposited on the polycrystalline silicon. After coating the spin-on glass in the groove, a photoresist is formed on the spin-on glass that does not include the groove, and then the spin-on glass in the groove is removed by etching, and then the polycrystalline polycrystalline glass remaining in the groove is removed. After removing the silicon by etching, the photoresist is removed, and then the CV
D. A semiconductor device manufacturing method for removing the spin-on glass remaining on the oxide film.