JPH03108314A - Manufacture of semiconductor element - Google Patents

Abstract

PURPOSE:To realize a simple and plain semiconductor element manufacturing process by using an ultraviolet rays irradiation baking method for hardening resists. CONSTITUTION:After an Si nitride film 2 is deposited on the entire surface of an Si substrate 1, a lower resist layer 3 is left by patterning and the film 2 is etched so as to keep the film 2 in the same form as that of the resist layer 3. Then field implanted areas 5 are formed by successively performing UV curing (ultraviolet rays irradiation baking), superimposing patterning on an upper resist layer 4 from the surface of the resist layer 3, and ion implantation. Then, after removing the resists 3 and 4 and making oxidization, the film 2 is removed. After removing the film 2, source-drain implanted areas 9 are formed by depositing polysilicon on the entire surface and performing patterning. Then, after depositing an intermediate insulating film 10 on the entire surface, contact holes 11 are patterned. Thereafter, Al wiring 12 is formed by deposing Al layer on the entire surface and performing patterning. Therefore, superimposing patterning can be performed stably and a simple and plain process can be realized.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to semiconductor devices, particularly photosensitive materials (photoresists).
The present invention relates to a method of manufacturing a semiconductor device in which patterning is performed by etching. [Summary of the Invention J The present invention relates to a technique for enabling overlapping patterning of resist in a method of manufacturing a semiconductor device,
Specifically, it was shown that overlapping patterning is possible using ultraviolet irradiation baking (UV irradiation baking).

[Conventional technology]

FIGS. 2A to 2C show a conventional method of manufacturing a semiconductor device without overlapping patterning. Here, the relationship between the patterns of two layers, a lower resist 20 and an upper resist 21, is shown. In other words, in FIG. 2(a), resist 2
After the nitride film 22 is patterned by etching using the pattern 0, the resist 20 is removed once, resulting in the state shown in FIG. 2(b). In this state, resist 2
1 from above, ion implanter 24
By doing so, an implant region 25 was formed as shown in FIG. 2(C). [Problem to be solved by the invention l Looking at the implant area 25 in FIG. 2(C), the second
It can be seen that there is no ion infrastructure in the area of the resist 20 in FIG. 2(a), so there is no need to remove the resist 20 in FIG. It is an attempt to solve problems. [Means for Solving the Problems J] In order to solve the above problems, in the present invention, ultraviolet irradiation baking (UV cure) is used to cure the resist, and overlapping patterning of the resist is performed. This is a method in which heat treatment is performed at the same time as the resist is irradiated with the resist, and is usually used to improve the heat resistance of the resist. [Operation 1] According to the manufacturing process of a semiconductor device according to the present invention, UV is applied to the lower resist in a state where the lower resist is patterned.
Apply cure. As a result, even if you apply resist on top of resist, the pattern shape of the underlying resist will not change.
Can be applied stably. Then, overlapping patterning of the resist becomes possible, and the wasteful process of removing the resist once can be omitted. [Example J Example 1 FIGS. 1(a) to 1(f) show cross-sectional views in the order of steps of the method for manufacturing a semiconductor device according to the present invention. First, as shown in FIG. 1(a), a Si nitride film is deposited on the entire surface of the Si substrate 1. Next, as shown in FIG. 1(b), the lower resist 3 is patterned and left, and the nitride 112 is etched. and leave it in the same shape as the lower resist 3 as shown in Figure 1 (
Apply UV curing in the state of b). The UV curing program at this time is shown in FIGS. 3 and 4. Here, FIG. 3 is a temperature program, and FIG. 4 is a program for ultraviolet irradiation intensity. , In this state, ion implantation 6 is performed, and the zero-order resist 3.4 that forms field implantation region 5 is completely removed and oxidized. Then, as shown in FIG. 1(d), there is no nitride film 2 In the first step, only the nitride film 2 is oxidized, as shown in FIG. 1(e). After that, the device shown in FIG. 1(f) is manufactured in the following order. First, polysilicon 8 is deposited on the entire surface and patterned, then a source/train implant 9 is formed, an intermediate insulating film 10 is deposited on the entire surface, and then contact holes 1O are patterned. Then, the AI wiring 12 is formed by depositing AI on the entire surface and patterning. In addition, here, in order to confirm the effect of UV cure, 2
We prepared several boards and changed the process for each board. In other words, one side is exactly the same as in Example 1, but the other side is the resist 4 shown in FIG. 1(C) without UV curing in the state shown in FIG. 1(b).
was applied. The UV curing program used here is the same as in Example 1, as shown in Figures 3 and 4, and the maximum temperature is 170°C.
It can be seen that it is. As a result, the substrate that was not subjected to UV curing was as shown in Figure 1 (C).
It was discovered that the shape of the lower resist layer 3 had collapsed, making it impossible to proceed to the next step. Example 2 In this example, the same steps as in Example 1 were carried out, but changes in the thickness of the lower resist 3 in FIG. 1 were measured at each step. The results are as follows. After developing lower resist 3 1.1 mm Lower resist 3 after UV curing 1.05 Mm upper resist 4
1.05 mm after development From this, it became clear that even if the upper layer resist 4 was exposed and developed, the lower layer resist 3 hardly decreased in thickness. [Effect of the Invention J As shown in the above embodiments, according to the present invention, stable overlapping patterning can be performed, and thereby a simple process can be realized.

[Brief Description of the Drawings] Figures 1 (a) to (f) are cross-sectional views in the order of steps of a method for manufacturing a semiconductor device according to the present invention, and Figures 2 (a) to (C) are conventional process steps for manufacturing a semiconductor device. FIG. 3 is a cross-sectional view showing the steps of the method, and FIG. 3 is a temperature program diagram for UV curing used in the embodiment of the present invention, and FIG. 4 is a program diagram for ultraviolet irradiation.・Si substrate, St nitride film, lower layer resist, upper layer resist, field implant area, ion implant, oxide film, polysilicon, source, train implant, intermediate insulation layer, contact hole, AI wiring and more

Claims (1)

[Claims] When manufacturing a semiconductor element by patterning a photosensitive material using exposure and development steps, 170% is added to the photosensitive material.
a step of performing ultraviolet irradiation baking at a temperature below ℃;
On the photosensitive material subjected to ultraviolet irradiation baking,
A method for manufacturing a semiconductor device using a process of applying a photosensitive material, exposing it to light, and developing it.