JPH0563250A - Manufacture of thin film element - Google Patents

Abstract

PURPOSE:To obtain good flatness when a thin film pattern is formed. CONSTITUTION:Etching is performed based upon a regist pattern 4 while an insulating film 3 is formed on a thin film 2 which is the target to be patterned. Then the insulating film 3 is formed again in order to fill the spaces between the patterned thin films 2, and after that, an etching stopper film 5 is formed. After the resist pattern 4 is removed by a lift-off method, the insulating film 3 corresponding to the patterned thin film 2 is removed by etching.

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 thin film element, and more particularly to a method for flattening a thin film pattern forming a thin film element.

[0002]

2. Description of the Related Art Conventionally, SQUID (Superconducting)
Quantum Interference Device)
When manufacturing a thin film element that is manufactured by stacking thin film patterns on a substrate like the above, in order to prevent disconnection etc. at the step of the thin film pattern, the thin film pattern should be as flat as possible without steps. It is known that it is preferable to fabricate and to laminate such a flattened thin film pattern.

A thin film pattern manufacturing method using a self-alignment method is known as a thin film pattern manufacturing method for satisfying such requirements. FIG. 3 is a vertical cross-sectional view for explaining a thin film pattern manufacturing method using the self-alignment method. A resist pattern 22 is formed on a thin film 21 to be patterned (see FIG. 3A), and reactive ion etching is performed. The unnecessary portion of the thin film 21 is removed by the method, the resist pattern 22 is made thin in the oxygen plasma atmosphere (see FIG. 3B), and then the insulating film 23 is filled to fill the space between the patterned thin films 21. Is formed (see FIG. 3C), and finally the resist pattern 22 and the insulating film 23 located on the resist pattern 22 are removed by a lift-off method (FIG. 3D).
reference).

If this self-alignment method is adopted, it is possible to prevent a space from being formed at the boundary between the patterned thin film 21 and the insulating film 23, and when a thin film is stacked, a step due to the space is generated. It can be prevented.

[0005]

However, in the case where the self-alignment method is adopted, when the resist pattern is removed by the lift-off method, the burr 22a remains on the peripheral portion of the patterned thin film 21. However, if the thin film patterns are stacked as they are, there is a problem that the burrs 22a cause insulation failure between layers and the yield of the thin film elements deteriorates.

Further, it has been proposed to dig down the substrate to achieve flatness in a method of manufacturing a dc-SQUID magnetometer having a thin film laminated structure (Japanese Patent Laid-Open No. 63-1).
No. 57081), the thin film pattern is formed by the lift-off method. Therefore, although flattening due to the digging can be achieved, burrs and the like remain during the production of the thin film pattern based on the lift-off method, resulting in poor insulation between layers. However, the inconvenience that such problems occur cannot be solved.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a novel thin film element manufacturing method capable of preventing generation of unnecessary spaces and burrs and achieving good planarization. Has a purpose.

[0008]

In order to achieve the above object, a method of manufacturing a thin film element according to claim 1 is such that after forming an insulating film on a thin film to be patterned, a thin film and an insulating film are formed by using a resist pattern. The film is patterned, the resist pattern is made slightly smaller than the patterned thin film, then the insulating film is formed, the etching stopper thin film is formed on this insulating film, and then the resist pattern is removed by the lift-off method. This is a method of removing an insulating film corresponding to a thin film patterned by etching.

According to a second aspect of the present invention, there is provided a method of manufacturing a thin film element, wherein after forming a different patterning target thin film on a patterning target thin film, the first resist pattern is used to pattern the thin film to form a first resist pattern. Is formed to be slightly smaller than the patterned thin film, an insulating film is formed, an etching stopper thin film is formed on the insulating film, and then the first resist pattern is removed by a lift-off method. Is used to pattern a thin film and simultaneously remove the insulating film corresponding to the thin film patterned based on the first resist pattern.

[0010]

According to the thin film element manufacturing method of the first aspect, the insulating layer is formed in advance on the thin film to be patterned, and then the thin film and the insulating layer are simultaneously patterned using the resist pattern. After that, an insulating layer is formed to fill the space between the patterned thin films, an etching stopper thin film is formed, the resist pattern is removed by a lift-off method, and etching is performed to correspond to the patterned thin film. Since the insulating film is removed, it is possible to prevent the formation of a space at the boundary between the patterned thin film and the insulating layer, and to prevent burrs from remaining on the peripheral edge of the patterned thin film, thus achieving good planarization. Can be achieved. As a result, the yield and reliability of the thin film element can be significantly improved.

According to the thin film element manufacturing method of claim 2, after forming different thin films to be patterned on the thin films to be patterned, the thin films laminated in a plurality of layers using the first resist pattern are formed. Pattern at the same time. Next, an insulating layer is formed so as to fill the space between the patterned thin films, an etching stopper thin film is formed, and then the resist pattern is removed by a lift-off method. After that, since only the uppermost thin film is patterned using the second resist pattern, and at the same time, the insulating film corresponding to the other thin films is removed, so that no distinction processing is performed after manufacturing the thin film element having the multi-layer structure. In addition, it is possible to prevent a space from being generated at the boundary between the patterned thin film and the insulating layer, and to prevent burrs from remaining at the peripheral edge of the patterned thin film, thereby achieving good planarization. As a result, the yield and reliability of the thin film element can be significantly improved, and the number of thin film element manufacturing steps can be prevented from increasing.

[0012]

Embodiments will now be described in detail with reference to the accompanying drawings showing embodiments. FIG. 1 is a vertical cross-sectional view for explaining an embodiment of the thin film element manufacturing method of the present invention. A MgO film 1 as an etching stopper film is formed on a substrate 1 made of a silicon wafer.
a, the Nb thin film 2 to be patterned and the SiO film 3 as an insulating layer are formed in this order by vapor deposition or the like, and then a resist pattern 4 is formed (see FIG. 1A). Specifically, a MgO film 1a having a film thickness of 20 nm is formed by electron beam evaporation, an argon gas pressure is 8 mTorr,
A 250 nm thick Nb thin film 2 is formed by a DC sputtering method with a current of 2 A, and a 250 nm thick Sb film is formed by vacuum evaporation.
The iO film 3 is formed, and the resist is patterned by using a photolithography technique. Then, using the resist pattern as a mask, for example, etching gas CF4, 20
The Nb thin film 2 and the SiO film 3 are patterned by reactive chemical ion etching with 0 mTorr and RF power of 100 W (see FIG. 1B). Next, for example, to fill the gap between the patterned Nb thin films 2 with each other, for example, 23
After the SiO film 3 having a film thickness of 0 nm is formed again by vacuum evaporation, the MgO film 5 as an etching stopper film is formed to have a film thickness of 20 nm by, for example, electron beam evaporation (FIG. 1C).
Then, the resist pattern 4 is removed by a lift-off method (for example, immersion in acetone for several hours and ultrasonic cleaning) (see FIG. 1D). Finally, for example, etching gas CF4, 20 mTorr, RF power 1
The reactive chemical ion etching of 00 W removes the SiO film 3 corresponding to the patterned Nb thin film 2 to achieve good planarization without unnecessary spaces and burrs (see FIG. 1E). The reactive chemical ion etching in this case is unnecessary S by controlling the time in consideration of the thickness of the SiO film 3 initially formed.
Only the iO film 3 can be removed. If it is necessary to remove the MgO film 5, wet etching with a weak acid may be performed. Further, the MgO film 5 exists on the SiO film 3 after the lift-off corresponding to the peripheral portion of the patterned Nb thin film 2, but the width of the MgO film 5 is extremely small, so that the reactive chemical ion is used. S by etching method
Since it is removed together with the iO film 3, the occurrence of burrs can be reliably prevented.

Since a flat thin film pattern having no unnecessary space and no burr can be produced as described above, good flatness can be easily achieved when a thin film element is manufactured by sequentially laminating thin film patterns. The occurrence of insulation failure between thin film pattern layers can be greatly reduced, and the yield of thin film elements and the reliability of thin film elements can be significantly improved.

[0014]

[Embodiment 2] FIG. 2 is a vertical sectional view for explaining another embodiment of the method for manufacturing a thin film element according to the present invention, in which Mg as an etching stopper film is formed on a substrate 11 made of a silicon wafer.
O film 11a, Nb thin film 12 to be patterned,
AlOx film 13 as an insulating layer and N to be an electrode
After the b thin film 14 is formed in this order by a sputtering method or the like, a first resist pattern 15 is formed (FIG. 2).
(See (A)). Specifically, the MgO film 11a having a film thickness of 20 nm is formed by electron beam evaporation, and the argon gas pressure is 8 m.
A 250 nm-thick Nb thin film 12, a 3 nm-thick AlOx film 13 and a 250 nm-thick Nb thin film 14 are formed by a DC sputtering method with a Torr and a current of 2 A, and a resist is patterned using a photolithography technique.
Then, using the first resist pattern 15 as a mask,
For example, etching gas CF4, 200 mTorr, RF
N by reactive chemical ion etching with power of 100W
The b thin film 12, the AlOx film 13, and the Nb thin film 14 are patterned (see FIG. 2B). However, in order to enhance the etching efficiency, it is preferable to perform reactive ion etching with an etching gas of CF4, 20 mTorr, and RF power of 100 W corresponding to the AlOx film. Then, a SiO film 16 having a film thickness of 250 nm, for example, is formed by vacuum evaporation so as to fill the space between the patterned Nb thin films 12, and then Mg as an etching stopper film is formed.
The O film 17 is formed to have a film thickness of 20 nm by, for example, electron beam evaporation (see FIG. 2C), and the first is formed by a lift-off method (for example, dipping in acetone for several hours and ultrasonic cleaning).
The resist pattern 15 is removed (see FIG. 2D). Then, a resist is patterned on the Nb thin film 14 by using a photolithography technique to form a second resist pattern 18 (see FIG. 2E), and finally,
For example, etching gas CF4, 200 mTorr, RF
By reactive chemical ion etching with power 100W,
By removing a portion of the Nb thin film 14 which is not covered with the second resist pattern 18, a Josephson junction is obtained, and good planarization without unnecessary space and burrs is achieved (FIG. 2 (F)). reference). Of course, after this process, the second resist pattern 18 is removed by the lift-off method or the like. If it is necessary to remove the MgO film 17, wet etching with weak acid may be performed. In addition, the MgO film 1 is formed on the SiO film 16 after lift-off corresponding to the peripheral portion of the patterned Nb thin film 14.
However, since the width of the MgO film 17 is extremely small, the MgO film 17 is removed together with the SiO film 16 by the reactive chemical ion etching method, and the occurrence of burrs can be reliably prevented.

Since a flat Josephson junction free from unnecessary spaces and burrs can be produced as described above, good flatness can be obtained when a thin film pattern is laminated on the Josephson junction to produce a thin film element. Can be easily achieved, and the occurrence of insulation failure between the Josephson junction and the thin film pattern layer can be greatly reduced, and the yield of thin film elements and the reliability of thin film elements can be significantly improved.

The present invention is not limited to the above-described embodiments, and for example, each layer can be made of different materials, and various design changes can be made within the scope not changing the gist of the present invention. Can be applied.

[0017]

As described above, according to the first aspect of the present invention, it is possible to prevent a space from being generated at the boundary between the patterned thin film and the insulating layer, and at the same time, the burr remains on the peripheral portion of the patterned thin film. It is possible to prevent the above phenomenon, achieve good planarization, and further significantly improve the yield and reliability of the thin film element.

According to the second aspect of the present invention, it is possible to prevent the formation of a space at the boundary between the patterned thin film and the insulating layer and perform the patterning without performing a special process after manufacturing the thin film element having the multi-layer structure. It is possible to prevent burrs from remaining on the peripheral edge of the thin film, achieve good planarization, and significantly improve the yield and reliability of the thin film element, and prevent an increase in the number of thin film element manufacturing steps. There is a unique effect.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view illustrating an embodiment of the method of manufacturing a thin film element of the present invention.

FIG. 2 is a vertical sectional view for explaining another embodiment of the method for manufacturing a thin film element of the present invention.

FIG. 3 is a vertical cross-sectional view illustrating a conventional example of a thin film element manufacturing method.

[Explanation of symbols]

2,12,14 Nb thin film 3,16 SiO film 4,15,18 Resist pattern 5,17 Mg
O film 13 AlOx film

Claims (2)

[Claims] 1. A resist pattern formed by forming an insulating film (3) on a thin film (2) to be patterned and then patterning the thin film (2) and the insulating film (3) with a resist pattern (4). The insulating film (3) is formed after making (4) slightly smaller than the patterned thin film (2), the etching stopper thin film (5) is formed on this insulating film (3), and then the lift-off method is used. A method for manufacturing a thin film element, comprising removing the resist pattern (4) and further removing an insulating film (3) corresponding to the thin film (2) patterned by etching. 2. A thin film (12) (1) to be patterned.
3) After forming different thin films (14) to be patterned on the thin film (12), (13) and (14) using the first resist pattern (15),
The resist pattern (15) is made slightly smaller than the patterned thin films (12), (13) and (14), and then the insulating film (16) is formed, and the etching stopper thin film (17) is formed on the insulating film (16). ) Is formed, the first resist pattern (15) is removed by a lift-off method, and a thin film (1) is formed using the second resist pattern (18).
The insulating film (16) corresponding to the patterned thin films (12) and (13) at the same time as the patterning of 4) is performed.
A method for manufacturing a thin film element, comprising: