JPH0254526A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the wear of films in a resist and afford dimensions and forms of etching which fit into resist patterns by injecting highly concentrated and low energized species of ions before performing a dry etching process, thereby setting the surface and sidewalls of a photoresist film. CONSTITUTION:A photoresist 2 is deposited to 1.0mum thickness on a silicon substrate 1 and it is patterned. Phosphorus ions are implanted into the surface of a pattern of the resist 2 by tilting ion beams at the angle of 7 deg. to the silicon substrate to form a setting layer 3. Then, the ions are implanted in accordance with the same conditions as mentioned above by tilting ion beams at the angle of 7 deg. either in the opposite or in the surrounding directions and the setting layer 3 is formed. After that, dry etching is performed to obtain dimensions and forms of etching which fit into expected photoresist patterns.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a semiconductor device that can be used for fine patterning.

2. Description of the Related Art FIGS. 2(a) to 2(d) are cross-sectional views showing the steps of patterning and dry etching a photoresist on one principal surface of a conventional semiconductor substrate, such as a silicon substrate. First, on a silicon substrate as shown in Fig. 2(a),
A photoresist is patterned on top, as shown in FIG. 2(b). Next, when dry etching is performed,
As shown in FIG. 2(C), the photoresist film is thinned, and as a result, an etched pattern as shown in FIG. 2(d), which is larger than the original photoresist pattern 2, is obtained.

Problems to be Solved by the Invention However, with the above-mentioned conventional structure, the photoresist film is thinned during dry etching, so there is a problem in that the target etched dimensions and shape cannot be obtained.

The present invention solves the above-mentioned conventional problems, and it is possible to prevent photoresist film thinning during dry etching and to obtain etched dimensions and etched shapes that match the target photoresist pattern. The purpose is to provide a method for manufacturing the device.

Means for Solving the Problems The present invention includes a step of patterning a photoresist on a film to be etched on one main surface of a semiconductor substrate, and implanting ion species by tilting an ion beam with respect to the one main surface. A method for manufacturing a semiconductor device comprising the steps of forming a hardened layer on the surface and sidewalls of the photoresist, and dry etching the one main surface, and the ion implantation concentration at this time is 5 x 10''cn+- 2~I x 10
"c+a-", implantation energy is 30KeV ~ 50K
eV is appropriate.

Effect: With this configuration, the reduction in photoresist film due to dry etching is significantly improved compared to the conventional method. Therefore, it is possible to improve the etching selectivity to resist, and it is possible to realize the target etching size and shape.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIGS. 1(a) to 1(f) are sectional views showing an embodiment of the present invention in the order of steps. First, as shown in Figure 1(a),
A photoresist 2 having a thickness of 1.0 μm is deposited on a silicon substrate 1 as shown in FIG. 1(b), and vertical patterning is performed by projection exposure. Next, as shown in FIG.
A hardened layer 3 is formed by implanting phosphorus ions at an angle of 7° with respect to the silicon substrate at 0"cm-2. Next, as shown in FIG.
), under the same conditions, phosphorus ions are implanted in opposite directions or at an angle of 7 degrees in each of the four directions to form a hardened layer 3. After that, dry etching is performed, and as shown in Fig. 1 (e)
), it is possible to obtain an etching method and etching shape that match the target photoresist pattern.

FIG. 1(f) shows the state with the photoresist removed.

According to the inventor's experiments, phosphorus ions are accelerated with an energy of 3
0KeV, 'dose 5 x 10'' (7 with Ml-2
When the photoresist pattern was implanted, cured, and then RIE dry etched using Freon gas, the photoresist film was reduced by about 1% compared to the conventional method.
It turned out to be 15.

In addition, when the ion beam was not tilted during ion implantation, but only in the direction perpendicular to the semiconductor substrate, the thinning of the photoresist film was suppressed, but the hardening in the sidewall direction of the photoresist pattern was not sufficient (the target The desired etching dimensions and etching shape could not be obtained.

Furthermore, the implantation energy during ion implantation is 50K.
When the voltage exceeds eV, if the ion species is B+, there is a possibility that it will reach the substrate. Furthermore, if the dose was less than 5×10 Ca1-'', the photoresist pattern could not be sufficiently cured, and the target etching dimensions and etching shape could not be obtained. The dose is I x 10
If it exceeds "cm-", the reproducibility and controllability are insufficient due to performance problems of the ion implanter.

Effects of the Invention As described above, the present invention implants high-concentration, low-energy ion species before the dry etching process to harden the surface and sidewalls of the photoresist, thereby preventing film thinning of the photoresist. Accordingly, it is possible to realize an excellent semiconductor device manufacturing method that can provide etching dimensions and etching shapes that are faithful to the photoresist pattern.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(f) are sectional views in the order of steps of an embodiment of the present invention, and FIGS. 2(a) to 2(d) are sectional views in the order of steps of a conventional example. 1...Silicon substrate, 2...Photoresist pattern, 3...Hardened layer by P+ ion implantation. Name of agent: Patent attorney Shigetaka Awano Idiot 1 figure (α) 1---Sirikoshiki Fume'z---27y Regis

Claims (2)

[Claims] (1) A process of patterning a photoresist on a film to be etched on one main surface of a semiconductor substrate, and tilting an ion beam with respect to the one main surface and implanting ion species, and forming a pattern on the surface of the photoresist and the same photoresist. A method for manufacturing a semiconductor device, comprising the steps of forming a hardened layer on a side wall and dry etching the one principal surface. (2) The implantation concentration of ion species is 5 × 10^1^4 cm^-
2. The method of manufacturing a semiconductor device according to claim 1, wherein the implantation energy is 30 KeV to 50 KeV.