JPS61174718A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce a number of manufacturing steps and manufacturing cost by executing the photorithography using the positives photo resist coated at first to the surface of semiconductor substrate also for the second and successive steps in the photorethography process to be continued twice or more. CONSTITUTION:The surface of semiconductor substrate 1 is coated with a positive photo resist 2 and it is then pre-baked. A photo resist pattern layer 5 is selectively formed by the mask alignment, exposure, developing process and first ion implantation is carried out. The part not exposed of the layer 5 is selectively exposed and developed by the mask alignment process in order to form another photo resist pattern layer 9. The second ion implantation is carried out thereto. Thereby, ion is implanted also to the window part of layer 5. In the same way, the photo resist 2 can be used in three times or more.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a semiconductor device, and particularly to an improvement in a photolithography process.

[Conventional technology]

In the conventional manufacturing method of semiconductor devices, when one step of IJ lithography is performed two or more consecutive times, for example, ions are implanted into the channel part of a transistor formed on the surface of the semiconductor substrate. In the channel doping process, and also in the double channel doping process in which ions are implanted into the channel part of a transistor whose threshold voltage is to be lowered than that of the previous transistor, a photo-optical process is performed to continuously implant ions into the channel part of the same transistor. When forming the resist pattern Z, a process such as the second flN(at~(jl) is generally performed.

First, a negative photoresist 2 is placed on the semiconductor substrate surface 1.
Coat and pre-bake. (Second Inner A) Next, by a mask alignment process (FIG. 2b), the photoresist pattern layer 5y! / Formation (21st Nc) L,
Using the patterned layer as a mask, the surface of the semiconductor substrate was irradiated with ions 6 such as holon ions and phosphorus ions to form an ion-implanted layer 7Z. (@Fig. 2 d) However, in order to form two or more consecutive photoresist pattern layers χ, the photoresist layer Y must be peeled off (Fig. 2 e), and a negative photoresist layer 8 must be applied again on the semiconductor substrate surface. After coating and pre-baking (FIG. 2r), mask alignment and exposure steps (FIG. 2g) were performed again to form the necessary photoresist pattern niqw. (Second
h) After that, a second ion implantation was performed (Fig. 2 1), and by peeling off the photoresist pattern Ii#9, an ion implanted layer 7.10 with different surface concentrations was selectively obtained. . (Fig. 2 j) [Invention 7>Problem to be solved by It is necessary to remove the resist, and the process is complicated and
There was a problem that work efficiency was reduced.

The present invention solves these problems and aims to reduce the number of steps per process and, in turn, reduce manufacturing costs.

[Means to solve problem Z]

The uninvented method for manufacturing semiconductor components is to carry out photolithography in two or more consecutive photolithography steps by using the positive type phosphatide initially applied to the surface of the semiconductor substrate, and using it from the second time onwards. This is assumed to be 2%.

[Effect]

Effects of the present invention χ In other words, the positive photoresist layer is
The areas exposed to light undergo a structural change due to an original optical reaction and are selectively dissolved in a developer, but the areas that are not exposed to light can be used for a second exposure process to pattern the photoresist. It is.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples.

FIGS. 1g to 1h are diagrams showing the steps of an embodiment of the present invention. First, a positive photoresist 2Y is applied onto the semiconductor substrate surface 1 and prebaked.

(FIG. 1g) Next, 5 photoresist pattern layers are selectively formed (FIG. 1g) by mask alignment, exposure, and development steps (first step h). However, in this case, it is necessary to form only a photoresist pattern to be used as a mask for the second ion implantation. Thereafter, using the photoresist pattern layer as a mask, two first ion press injections are performed.

(FIG. 1 d) Next, the unexposed portions of the photoresist pattern layer are selectively exposed and developed by a mask alignment process (θ in FIG. 1), forming another photoresist pattern layer 9. ′? :Form.

(See FIG. 1) Next, by performing two second ion implantations, implantation is also performed in the window opening portion of the photoresist pattern layer that was previously formed. (FIG. 1g) Thereafter, by peeling off the photoresist pattern layer, an ion-implanted layer 7.10 having a different surface concentration was obtained. (First prisoner h) Here, an example χ of a photolithography process performed twice consecutively is shown, but the photolithography process is performed three times consecutively to form three ion-implanted layers with different degrees of irradiation. The same goes for forming the required photoresist pattern layer three times in a row.
The positive photoresist χ initially applied to the surface of the semiconductor substrate can be effectively utilized. The more continuous photolithography steps are performed in this way, the more the repeated photoresist coating, pre-evaporation, and photoresist peeling steps can be omitted.

[Effects of the present invention]

As described above, according to the manufacturing method of the present invention, the photoresist coating, shift baking, and photoresist peeling steps that are repeatedly performed in two or more consecutive photolithography steps can be omitted. That is, the cost of the semiconductor device can be reduced by reducing the number of manufacturing steps, the number of photoresist and development steps, and the reduction in yield due to dust adhesion during photoresist application can be suppressed to the necessary minimum.

In addition, the photoresist pattern j that is repeatedly formed
Because # remains after the test, patterns can be recognized.
It can be used for mask alignment patterns and can prevent omissions in the mask alignment process.

[Brief explanation of drawings]

FIG. 1 (at~(hl) is a diagram of all embodiments of the invention. FIG. 2 (al~(jl is a diagram of a conventional embodiment). 1...Semiconductor substrate 2... Negative photoresist 3...Glass mask 4...Light 5...Negative photoresist pattern 6...
... Ion beam 7 ... Ion implantation layer 8 ... Negative photoresist 9 ... Negative photoresist pattern 10 ...
. . . Ion-implanted layer FIG. 1 is in an embodiment according to the present invention. 1...Semiconductor substrate 2...Positive photoresist 5...Positive photoresist pattern 7...
...Ion implantation layer 9...Positive photoresist pattern 10...
...Ion implantation layer. that's all

Claims (1)

[Claims] A semiconductor device characterized in that, in two or more consecutive photolithography steps, a positive photoresist coated on the surface of a semiconductor substrate is used for the second and subsequent photolithography steps in manufacturing the semiconductor device. manufacturing method