JPS60117671A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To enable to perform the formation of patterns without using an etching process and to form another electrodes or wirings on the same plane as electrodes or wirngs having been formed earlier after a lift-off method was applied for removing metal layers, photo resists and insulating films by a method wherein the electrodes or wirings having been formed earlier and insulating films, which are formed on the electrodes or wirings, are respectively formed using lift-off films as a mask respectively. CONSTITUTION:An insulating film 2, a photo resist (lift-off film) 8 and a metal layer (lift-off film) 9 are formed on a semiconductor substrate 1. Apertures 10 are provided on the metal layer 9, and further-more apertures 11 wider than the apertures 10 are provided on the photo resist 8 and electrodes 3 are formed on the insulating film 2 using the metal layers 9 as a mask respectively. The metal layers 9 and the metal layers 3 thereon are removed by a lift-off method and interlayer insulating films 4 are formed on the electrodes 3 using the photo resists 8 as a mask respectively. After the photo resists 8 and the insulating films 4 thereon were removed by a lift-off method, an electrode 6 and an insulating film 7 are fomred. As an etching process is not used, such troubles as a stain of an etching liquid appears and a uniformity of etching is bad don't arise. As a result, a charge transfer device having superior characteristics can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (11) Object of the Invention The present invention relates to a method for manufacturing a semiconductor device having a plurality of electrodes or wirings on the same plane on a semiconductor substrate via an insulating film, and particularly relates to a method for manufacturing a semiconductor device having a plurality of electrodes or wirings on the same plane through an insulating film on a semiconductor substrate. and charge injection device (
This invention relates to an effective method for producing CI D) and the like.

(2) Prior art and problems A charge transfer device is a device that consists of multiple electrodes, forms potential wells in a semiconductor substrate under the electrodes, and transfers charges by periodically changing the depth of the potential wells. It is. In this charge transfer device, a method has been considered in which each electrode is arranged on the same plane, and when all electrodes are set to the same potential, a potential well of the same depth is formed. In this way, it is easy to set the potential of each electrode, and reliable and stable charge transfer can be performed by manipulating the potential of each electrode. Next, a conventional method of forming a plurality of electrodes on the same plane will be described.

After forming an insulating film 2 on a semiconductor substrate 1''2 as shown in FIG. 1(a) and forming a first electrode 3 as shown in FIG. 4 is formed, and the insulating film 4 is partially removed by etching as shown in the figure (dl).
An opening 5 is provided. Next, as shown in the same figure (C), the second electrode 6
is formed, and the insulating film 7 is formed as shown in FIG. Generally, the electrodes 3.6 are made of polysilicon and the insulating film 4 is made of a thermal oxide film.When etching this thermal oxide film to form the electrode 6, if the electrode 6 gets contaminated with etching liquid, it will be contaminated and the characteristics will deteriorate. In addition, when a compound semiconductor substrate is used as the semiconductor substrate 1, the electrodes 3 and 6 are made of a metal 2, for example, Au Ge
/ Au, etc., and the insulation 11 and the moxibustion 4 are formed by a vapor deposition film by vacuum evaporation, sputtering, CVD, etc. This patterning of a deposited film by etching has disadvantages in that the etching solution may seep onto the pattern and the etching uniformity is poor.

(3) Purpose of the Invention The purpose of the present invention is to form an electrode or wiring and an insulating film formed thereon using a lift-off film as a mask, thereby forming a pattern without etching the insulating film on the electrode or wiring. The object of the present invention is to provide a method in which another electrode or wiring can be formed on the same plane as the electrode or wiring after lift-off.

(4) Structure of the Invention According to the present invention, a step of forming a first lift-off film on a semiconductor substrate on which a first insulating film is formed; forming a second lift-off film different in type from the first lift-off film, and then partially removing the second lift-off film to provide a second opening; removing the first lift-off mirror portion and providing a first opening wider than the second flowering portion to expose the first insulating film;
The first conductive layer different from the second lift-off film is
forming a lift-off film on the insulating crotch as a mask;
a step of removing the conductive layer by a lift-off method;
forming a second insulating film on the first conductive layer using the lift-off method as a mask; removing the first lift-off film and the second insulating film on the film by a lift-off method; This is achieved by comprising the steps of exposing the first insulating film and forming a second conductive layer on the exposed portion of the first insulating film.

(5) Embodiment of the Invention FIGS. 2 to 8 are side sectional views of a semiconductor device at important points in the process for explaining an embodiment of the present invention, and the description will be made with reference to these figures.

In order to form a plurality of electrodes of a charge transfer device on the same plane using the method of the present invention, first, as shown in FIG. After forming the first resist 8 to a thickness of, for example, 1 μrn,
For example, the metal layer 9 made of aluminum has a thickness of, for example, 30 mm.
Approximately 00 people will be formed.

Next, as shown in FIG. 3, the metal layer 9 is partially removed to form an opening 1O. Further, the photoresist 8 is removed from the same portion to provide an opening 11 wider than the opening 10 of the metal layer 9, and the insulating film 2 is exposed.

Next, as shown in Fig. 4, for example, A u G e / A u
The metal layer 3 is deposited to a thickness of, for example, about 1,000 layers.

The metal layer 9 is deposited by sputtering or CVD.
An electrode 3 is formed on the insulating film 2 using as a mask. Here, since the metal layer is used as a mask, highly accurate electrodes can be formed.

The metal layer 9 and the metal layer 3 on the metal layer 9 are removed by a riff 1-off method, and as shown in FIG. 5, an insulating film 4 made of silicon dioxide is deposited to a thickness of about 2000 by evaporation, as shown in FIG. Interlayer insulating film 4 is formed on electrode 3 using photoresist 8 as a mask. Here, since the opening 11 in the photoresist is made wider than the opening 10 in the metal layer 9, the electrode 3 is almost completely covered by the interlayer insulating film 4.

As shown in FIG. 6, the first resist 8 used as a mask and the insulating film 4 on the first resist 8 are removed by a lift-off method to expose the insulating film 2.

Then, as shown in FIGS. 7 and 8, an electrode 6 and an insulating film 7, which operate differently from the electrode 3, are formed. Therefore, electrode 3 and electrode 6 can be formed on the same plane, and when each electrode has the same potential, potential wells of the same depth are formed, so it is easy to set the potential of each electrode. , reliable and stable charge transfer can be performed by manipulating the potential of each electrode.

Further, the electrode 3 and the insulating film 4 on the insulating film 2 are replaced with a metal layer 9.
．． The insulation 1ii! is formed using the lift-off film of the photoresist 8 as a mask, and the electrode 6 is formed by lift-off of the photoresist 8 without etching. 2 can be exposed, so there is no problem of bleeding of etching solution or poor etching uniformity when etching is used, and a charge transfer device with good characteristics can be obtained.

Note that although a charge transfer device has been described in this embodiment, the present invention is not limited to charge transfer devices;
It can also be used in semiconductor devices having multiple electrodes or wiring other than charge transfer devices. Further, it is also effective to use a compound semiconductor substrate as the semiconductor substrate.

(6) Effects of the Invention According to the present invention, when forming a plurality of electrodes or wirings on a semiconductor substrate via an insulating film, each of some of the electrodes or wirings and the glabella insulating film formed thereon is removed using a lift-off film. By forming a mask as a mask and performing lift-off, the top of the insulating film is exposed without using an etching solution, and another electrode or wiring can be formed on the same plane as the electrode or wiring, so that the etching solution will not seep in due to etching. There is no problem of poor etching uniformity, and a semiconductor device with good characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side cross-sectional view of a charge transfer device at a key process point for explaining a conventional example, and FIGS. 2 to 8 are a side sectional view of a charge transfer device at a key process point G for explaining the present invention-embodiment. It is a side IJJi view of . In the figure, 1 is a semiconductor substrate, 2 and 4.7 are insulating films (silicon dioxide), 3.6 is a conductive layer, 5° 10.11 is an opening, and 8.9 is a lift-off 119. Grass 1 Illustration 6 Mouth

Claims (1)

[Claims] forming a first lift-off film on the semiconductor substrate on which the first insulating film has been formed, a second lift-off film different in type from the first lift-off pattern 1 on the first lift-off film; After that, a step of partially removing the second lift-off film to form a second aperture, removing a portion of the first lift-off film of the second aperture, and forming the second aperture. a step of exposing the first insulating film by providing a wider first opening; forming a first conductive layer different from the second lift-off film on the insulating film using the second lift-off film as a mask; forming the second lift-off film and the first conductive layer on its crotch by a lift-off method; removing the first lift-off film, forming a second insulating film on the first conductive layer using the first lift-off film as a mask, and removing the first lift-off film and the second insulating film thereon by a lift-off method. 1. A method of manufacturing a semiconductor device, comprising the steps of: removing the first insulating film by removing the first insulating film to expose the first insulating film; and forming a second conductive layer on the exposed portion of the first insulating film.