JP2000058546A - Lift-off method and organic film removing device - Google Patents

Abstract

(57) Abstract: The present invention can form a fine pattern composed of a predetermined metal film with high reliability,
An object of the present invention is to provide a lift-off method capable of preventing the re-adhesion of the lifted-off film pieces and generation of “burrs”, and an organic film removing apparatus used for carrying out the lift-off method. SOLUTION: Dry ice particles are ejected from ejection ports of a plurality of nozzles, and high-speed spraying of dry ice particles toward the surface of a Si wafer 10 is performed. Then, the photoresist 1 of the lift-off pattern on the Si wafer 10 is
2 and Ti / Au metal film 1 on photoresist 12
4b, and the flow of strong dry ice particles to remove the Ti / Au metal film 14c which may become a "burr" in the future on the side wall of the photoresist 12 and prevent these film pieces from re-adhering to the surface of the Si wafer 10. Wash off with.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lift-off method and an organic film removing apparatus, and more particularly to a lift-off method used in a semiconductor device manufacturing process and an organic film removing apparatus used for carrying out the lift-off method.

[0002]

2. Description of the Related Art A lift-off method using an organic substance such as a resist is used in a process of manufacturing a semiconductor device, for example, when forming a metal wiring of a predetermined pattern on a semiconductor substrate. And such a lift-off method,
Generally, it is performed through the following steps.

[0003] For example, after a photoresist is applied on a Si (silicon) wafer as a semiconductor substrate, it is patterned into a predetermined shape using a photolithography technique. Thus, a lift-off pattern for forming the metal wiring is manufactured. Subsequently, a metal film is deposited on the entire surface of the base using a vacuum deposition machine. At this time, since the photoresist of the lift-off pattern is formed on the Si wafer, a metal film directly deposited on the Si wafer and a metal film deposited on the photoresist are formed.

[0004] Subsequently, the entire substrate is immersed in an organic solvent to dissolve the photoresist on the Si wafer. Thus, together with the photoresist on the Si wafer, the metal film deposited on the photoresist is also removed, leaving only the metal film deposited directly on the Si wafer. Thus, a metal wiring of a predetermined pattern made of the metal film left on the Si wafer is formed.

As described above, the lift-off method is useful as a means for patterning a difficult-to-etch metal film into a predetermined wiring pattern or the like in a semiconductor device manufacturing process.

[0006]

However, in the above-described conventional lift-off method, when the photoresist and the metal film thereon are removed, the dissolution of the resist by the organic solvent is used, so that the organic solvent is hardly penetrated. In the case of a fine pattern, there is a problem that it is difficult to reliably execute the lift-off method.

In addition, when the photoresist and the metal film thereon are removed, when the entire substrate is lifted from the organic solvent, the lifted-off photoresist and the metal film pieces are reattached to the substrate surface. there were.

Further, when a metal film is deposited on the entire surface of the substrate, the flying metal particles have not only a velocity component in a direction perpendicular to the substrate surface but also a velocity component in a direction obliquely colliding with the substrate surface. Also, a metal film may be formed on the side wall of the resist of the lift-off pattern, and the metal film on the side wall may be connected to the metal film directly deposited on the Si wafer. Therefore, when the photoresist and the metal film thereon are removed to form a metal wiring made of the metal film left on the Si wafer, the metal film on the side wall of the resist becomes S
There is a problem that the metal wiring on the i-wafer remains as "burrs" attached thereto.

As described above, the conventional lift-off method is useful as a means for patterning a difficult-to-etch metal film into a predetermined shape, but it is a process with low reliability for forming a fine-pattern metal wiring. LSIs that require extremely fine design rules
(Large-scale integrated circuits) are not employed in the manufacturing process.

The present invention has been made in view of the above problems, and it is possible to form a fine pattern made of a predetermined metal film with high certainty, and to re-attach a lifted-off film piece or to obtain a fine pattern. It is an object of the present invention to provide a lift-off method capable of preventing occurrence of "burrs" and an organic film removing apparatus used for performing the lift-off method.

[0011]

The above objects are achieved by the following lift-off method and organic film removing apparatus according to the present invention. That is, the lift-off method according to claim 1 comprises, after patterning an organic film applied on a substrate into a predetermined shape, a first step of depositing a predetermined metal film on the entire surface of the base;
A second step of spraying the solid particles over the entire surface of the substrate to remove the metal film on the organic film together with the organic film, and forming a predetermined pattern made of the metal film on the substrate. .

As described above, in the lift-off method according to the first aspect, when the metal film on the organic film is removed together with the organic film patterned on the substrate, the dissolution of the organic film by the organic solvent is used as in the related art. Instead, by using a technique of spraying solid particles, the size of the solid particles is sufficiently reduced and the speed of the spraying is sufficiently increased to obtain a conventional fine pattern in which an organic solvent is difficult to enter. However, it is possible to reliably remove the organic film and the metal film thereon.

Further, even if a metal film is formed on the side wall of the patterned organic film on the substrate and there is a possibility that the film will become a "burr" in the future, the side wall is blown together with the organic film by spraying solid particles at high speed. The metal film on the side wall of the resist does not remain as "burrs" when a predetermined pattern made of the metal film left on the substrate is formed. Furthermore, the organic film removed by the high-speed spraying of the solid particles and the metal film thereon and the metal film on the side wall thereof are washed away by the strong flow of the solid particles. There is little risk of the pieces re-adhering to the substrate surface.

The lift-off method according to claim 2 is
In the lift-off method according to the first aspect, when the solid particles are sprayed on the entire surface of the substrate, the solid particles are sprayed in an O ₃ (ozone) atmosphere, whereby an effect of removing organic substances by spraying the solid particles is provided. In addition, the organic matter removing effect of O ₃ is added, and the organic matter removing ability is strengthened.
The organic film, the metal film thereon and the metal film on the side wall thereof can be more reliably removed.

The lift-off method according to claim 3 is
In the lift-off method according to claim 2, when the solid particles are sprayed on the entire surface of the substrate, ultraviolet rays (Ultr
a-Violet Ray; hereinafter referred to as “UV ray”), the solid particles are sprayed while irradiating the solid particles with the effect of removing organic substances by spraying solid particles and the effect of removing organic substances by O ₃ and UV rays. The organic substance removing effect by irradiation is added in combination, and the organic substance removing ability is further strengthened. Therefore, even in the case of an organic film having a fine pattern, the organic film and the metal film on the organic film and the side wall of the organic film are further more reliably. The metal film can be removed.

The lift-off method according to claim 4 is
The lift-off method according to claim 1, wherein the solid particles are formed by blowing a gas, a liquid, or a mixture of a gas and a liquid from a nozzle, and cooling the solid particles by adiabatic expansion at that time. It is possible to easily obtain solid particles for removing organic substances by spraying. At this time, the size of the solid particles is controlled by the size of the nozzle orifice of the nozzle, and the blowing speed of the solid particles is determined by the blowing speed of gas, liquid, or a mixture of gas and liquid from the nozzle, and thus the supply speed to the nozzle. It is controlled by the pressure of gas or the like.

In the lift-off method according to the first aspect, it is preferable to use dry ice particles which are solid CO ₂ (carbon dioxide) as the solid particles. In this case, dry ice particles can be easily formed by the adiabatic expansion of gaseous CO _{2 and} the adiabatic expansion of liquid CO ₂ . Further, by using dry ice particles, the lift-off step can be performed by a dry process. Instead of using dry ice particles as solid particles, solid H ₂
O ice particles may be used.

Further, the organic film removing apparatus according to claim 7 comprises:
A stage on which a substrate is mounted, and a plurality of nozzles installed above the stage and blowing out a gas, a liquid, or a mixture of a gas and a liquid, and cooling by adiabatic expansion at that time to form solid particles and blow out. Solid particles ejected from a plurality of nozzles are sprayed on the entire surface of the substrate mounted on the stage to remove a predetermined metal film deposited on the organic film together with an organic film of a predetermined pattern formed on the substrate It is characterized by the following.

As described above, in the organic film removing apparatus according to the seventh aspect, the solid particles are ejected from the plurality of nozzles installed above the stage on which the substrate is mounted. Instead of utilizing the dissolution of the resist by the organic solvent, the solid particles from the plurality of nozzles can be sprayed on the entire surface of the substrate on the stage to remove the organic film of a predetermined pattern formed on the substrate. Therefore, even in the case of the conventional fine pattern in which the organic solvent is difficult to enter, the organic film, the metal film thereon, and the metal film on the side wall thereof can be surely removed. At this time, the size of the solid particles is controlled by the size of the nozzle orifice of the nozzle, and the blowing speed of the solid particles is controlled by the blowing speed of gas, liquid, or a mixture of gas and liquid from the nozzle. The particle size can be made sufficiently small and the spraying speed can be made sufficiently high, so that the organic substance removing effect can be sufficiently exhibited.

Further, the organic film removing apparatus according to claim 8 is
8. The organic film removing apparatus according to claim 7, wherein the ejection ports of the plurality of nozzles are oriented in a direction inclined from a direction perpendicular to the surface of the substrate mounted on the stage, and the stage is mounted and rotated. Since the solid particles ejected from the plurality of nozzles are obliquely sprayed onto the organic film having a predetermined pattern formed on the substrate, the organic film and the metal film thereon and the metal film on the side wall thereof are formed. Is easily removed, and at that time, the substrate mounted on the stage rotates, so that the effect of removing the organic film, the metal film thereon, and the metal film on the side walls thereof is uniformly exerted on the entire surface of the substrate. .

Further, the organic film removing apparatus according to claim 9 is
8. The organic film removing apparatus according to claim 7, wherein the plurality of nozzles are configured to rotate above the stage, so that the solid particles ejected from the plurality of rotating nozzles are sprayed on the entire surface of the substrate while performing a spiral motion. Therefore, compared to the case where solid particles are sprayed from a fixed nozzle, solid particles are sprayed over the entire surface of the substrate from various angles, so that the incident angle with respect to the organic film patterned on the substrate takes various values. Thus, the organic film and the metal film thereon can be uniformly and extremely effectively removed over the entire surface of the substrate.

According to a tenth aspect of the present invention, in the organic film removing apparatus according to the ninth aspect, the rotation of the plurality of nozzles is induced by a reaction when the solid particles are ejected from the plurality of nozzles. With this configuration, no special power is required to rotate the plurality of nozzles, so that the apparatus is simplified and its operating cost is reduced.

[0023]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described. (First Embodiment) In a lift-off method according to a first embodiment of the present invention, a resist as an organic film patterned on a semiconductor substrate and a metal film on the resist are removed by a conventional method. It is characterized in that a method of spraying dry ice particles as solid particles is used instead of using the dissolution of resist by a solvent.

An example of forming a metal wiring having a width of 0.3 μm on a semiconductor substrate by the lift-off method according to the present embodiment will be described with reference to FIGS. here,
1 to 4 are process cross-sectional views for explaining a lift-off method according to the present embodiment. 8.0 μm thick on a Si (silicon) wafer 10 as a semiconductor substrate
After applying the photoresist, the photoresist is patterned into a predetermined shape using a photolithography technique. Thus, a photoresist 12 having a lift-off pattern having a linear opening having a width necessary for forming a metal wiring having a width of 0.3 μm is formed. At this time, the photoresist 12 of the lift-off pattern is
In order to facilitate lift-off in a later step, the cross section is made to have an inverted tapered shape (see FIG. 1).

Subsequently, using a vacuum evaporation machine, a film thickness of 10 n
An Ti (titanium) film having a thickness of m and an Au (gold) film having a thickness of 490 nm are sequentially deposited to form a Ti / Au metal film for a metal wiring having a laminated structure. At this time, since the photoresist 12 having the lift-off pattern is formed on the Si wafer 10, the Ti / Au metal film 14a is formed on the Si wafer 10.
Is directly deposited, and Ti / A
The u metal film 14b is deposited.

When the Ti / Au metal film is deposited, the flying metal particles have not only a velocity component in a direction perpendicular to the surface of the Si wafer 10 but also a velocity component in a direction obliquely colliding with the surface of the Si wafer 10. Therefore, Ti / Ti is also applied to the side wall of the photoresist 12 of the lift-off pattern.
The Au metal film 14c is formed so as to be connected to the Ti / Au metal film 14a (see FIG. 2).

Subsequently, the Si wafer 10 is mounted on a stage (not shown) provided in a chamber (not shown) of the organic film removing apparatus. Then, the stage is rotated at a rotation speed of, for example, 20 rpm while the Si wafer 10 is mounted. A plurality of fixed nozzles (not shown) are provided above the stage, and the ejection ports of the plurality of nozzles are, for example, 10 ° from a direction perpendicular to the surface of the Si wafer 10 mounted on the stage. It is pointing in a tilted direction. Then, dry ice particles are ejected from the ejection ports of the plurality of nozzles, and as shown by arrows in FIG.
A high-speed dry ice particle spray 16 toward the surface of the i-wafer 10 is performed.

The spraying of the dry ice particles 1
6 is a gas, liquid, or mixed gas and liquid
₂ is supplied to the nozzle, blown out from the nozzle, and is cooled by adiabatic expansion at that time, whereby it is easily formed. In addition, the size of the dry ice particles at this time is controlled by the size of the nozzle orifice of the nozzle, and the blowing speed of the dry ice particles is determined by blowing CO _{2 in} a gas, liquid, or a mixed state of gas and liquid from the nozzle. It is controlled by the speed and thus the pressure of the CO ₂ supplied to the nozzle.

In this manner, by spraying high-speed dry ice particles 16 on the surface of the rotating Si wafer 10, the photoresist 1 having the lift-off pattern on the Si wafer 10 and the photoresist 1 are removed.
2 on the Ti / Au metal film 14b and the Ti / A
The u metal film 14c is removed. As a result, the Si wafer 1
0, only the Ti / Au metal film 14a remains in the wiring pattern having a width of 0.3 μm.
A Ti / Au metal wiring 18 of 0.3 μm width is formed.

As described above, according to the present embodiment, the Si wafer 1 is sprayed by the high-speed dry ice particle spraying 16.
By removing the Ti / Au metal film 14b thereon along with the photoresist 12 of the lift-off pattern on the top of the mask 12, the lift-off pattern by the photoresist 12 is a fine pattern that is difficult to penetrate sufficiently when a conventional organic solvent is used. However, the photoresist 12 having a fine pattern and the Ti / Au metal film 14b thereon can be surely removed. Therefore, a fine pattern of Ti / Au is formed on the Si wafer 10 by the dry process.
The metal wiring 18 can be formed accurately and reliably.

Further, even when the Ti / Au metal film 14c is formed on the side wall of the photoresist 12 in a state of being connected to the Ti / Au metal film 14a when depositing the Ti / Au metal film, the side wall of the photoresist 12 may be formed. Ti / Au metal film 1
4c can be easily removed together with the photoresist 12 by high-speed dry ice particle spraying 16, so that the Ti / Au metal film 14c adheres as "burrs" to the Ti / Au metal wiring 18 formed on the Si wafer 10. Can be prevented.

The photoresist 12 and Ti / Ti removed by the high-speed dry ice particle spraying 16 are also used.
Since the Au metal films 14b and 14c are washed away by the strong flow of dry ice particles, the photoresist 12 and the Ti / Au metal film 14b once lifted off are removed.
The film piece 14c can be prevented from re-adhering to the surface of the Si wafer 10.

When the dry ice particles are sprayed 16, the dry ice particles are sprayed obliquely toward the surface of the rotating Si wafer 10 from the outlets of the plurality of nozzles, so that the photo by the dry ice particle spray 16 is formed. The effect of removing the resist 12 etc.
0 can be exerted uniformly over the entire surface.

(Second Embodiment) The lift-off method according to the second embodiment of the present invention is similar to the lift-off method according to the first embodiment, except that a resist as an organic film patterned on a semiconductor substrate and a In order to remove the metal film on the resist, a method of spraying dry ice particles as solid particles is used, and at that time, irradiation with UV rays in an O ₃ atmosphere is performed.

An example in which a 0.3 μm-wide metal wiring is formed on a semiconductor substrate by the lift-off method according to this embodiment will be described with reference to FIGS. here,
1 to 4 are process cross-sectional views for explaining a lift-off method according to the present embodiment. After coating a photoresist having a thickness of 8.0 μm on a Si wafer 20 as a semiconductor substrate, using a photolithography technique,
This photoresist is patterned into a predetermined shape.
Thus, a photoresist 22 having a lift-off pattern having a linear opening having a width necessary for forming a metal wiring having a width of 0.3 μm is formed. At this time, the cross section of the photoresist 22 of the lift-off pattern has an inverted tapered shape to facilitate lift-off in a later step (see FIG. 5).

Subsequently, using a vacuum evaporation machine, a film thickness of 10 n
Then, a Ti film having a thickness of m and a Au film having a thickness of 490 nm are sequentially deposited to form a Ti / Au metal film for a metal wiring having a laminated structure. At this time, since the photoresist 22 of the lift-off pattern is formed on the Si wafer 20, the Ti / Au metal film 24a is directly deposited on the Si wafer 20, and the Ti / Au metal is deposited on the photoresist 22. Membrane 24b
Is deposited.

When the Ti / Au metal film is deposited, the flying metal particles have not only a velocity component in a direction perpendicular to the surface of the Si wafer 20 but also a velocity component in a direction obliquely colliding with the surface of the Si wafer 20. Therefore, Ti / Ti is also applied to the side wall of the photoresist 22 of the lift-off pattern.
The Au metal film 24c is formed in a state of being connected to the Ti / Au metal film 24a (see FIG. 6).

Subsequently, the Si wafer 1 is placed on a stage (not shown) installed in the chamber 26 of the organic film removing apparatus.
0 is mounted. Then, the stage is rotated at, for example, a rotation speed of 20 rpm while the Si wafer 20 is mounted.
In addition, O ₃ is introduced into the chamber 26 using O ₂ (oxygen) gas as a carrier, and is filled with, for example, an O ₃ atmosphere 28 having a concentration of 15%. The total flow rate of the O ₃ and O ₂ gases at this time is, for example, 2 SLM. Further, a UV light source (not shown) is provided at an upper portion in the chamber 26, and as shown by a thick arrow in the drawing, S
For example, a light intensity of 200 mW /
Irradiation 30 of cm ² UV rays is performed.

A plurality of fixed nozzles (not shown) are provided above the stage, and the ejection ports of the plurality of nozzles are connected to the Si wafer 2 mounted on the stage.
0, for example, in a direction inclined by 10 ° from a direction perpendicular to the surface. Then, dry ice particles are ejected from the ejection ports of the plurality of nozzles, and high-speed spraying 32 of the dry ice particles toward the surface of the Si wafer 20 is performed as shown by a thin arrow in the figure.

The dry ice particles spray 3
2 is a gas, liquid, or mixed gas and liquid
₂ is supplied to the nozzle, blown out from the nozzle, and is cooled by adiabatic expansion at that time, whereby it is easily formed. In addition, the size of the dry ice particles at this time is controlled by the size of the nozzle orifice of the nozzle, and the blowing speed of the dry ice particles is determined by blowing CO _{2 in} a gas, liquid, or a mixed state of gas and liquid from the nozzle. It is controlled by the speed and thus the pressure of the CO ₂ supplied to the nozzle.

As described above, in the O ₃ atmosphere 28,
By performing high-speed dry ice particle spraying 32 on the surface of the rotating Si wafer 20 while receiving the radiation 30, the lift-off pattern photoresist 22 on the Si wafer 20 and the Ti / Au metal film 24b and Ti /
The Au metal film 24c is removed. As a result, only the Ti / Au metal film 24a remains on the wiring pattern having a width of 0.3 μm on the Si wafer 20, and this Ti / Au metal film 24a
A Ti / Au metal wiring 34 having a width of 0.3 μm is formed.

As described above, according to the present embodiment, the photoresist of the lift-off pattern on the Si wafer 20 is sprayed from the plurality of fixed nozzles 32 onto the surface of the rotating Si wafer 20 by spraying high-speed dry ice particles obliquely. 22 and Ti / Au metal film 24b thereon
By uniformly removing the Ti / Au metal film 24c on the entire surface of the Si wafer 10 and the sidewalls thereof, the lift-off of the photoresist 12 and the Ti / Au metal films 14b and 14c are performed in the same manner as in the first embodiment. Reattachment of the film pieces to the surface of the Si wafer 10 or the Ti / Au metal film 2
A fine pattern of the Ti / Au metal wiring 18 can be accurately and reliably formed by a dry process while preventing adhesion as a "burr" of 4c.

Further, according to the present embodiment, when the high-speed dry ice particle spraying 32 is performed, the O ₃ atmosphere 28
By accompanying the irradiation 30 of UV rays, the removal effect by O ₃ and the removal effect by irradiation 30 of UV rays are added in combination with the effect of removing the photoresist 12 and the like by spraying 32 of dry ice particles, Since the ability to remove the photoresist 12 and the like as a whole is enhanced, the photoresist 22 of the lift-off pattern and the Ti / Au metal film 24b and the T on the side wall
The i / Au metal film 24c can be removed. Therefore, it is possible to further increase the reliability in forming the fine pattern Ti / Au metal wiring 18 with high accuracy.

(Third Embodiment) A lift-off method according to a third embodiment of the present invention is similar to the lift-off method according to the first embodiment, except that a resist as an organic film patterned on a semiconductor substrate and a resist as an organic film are formed. In order to remove the metal film on the resist, a method of spraying dry ice particles as solid particles is used. In this case, a feature is that an automatic rotation type nozzle is used instead of a fixed type nozzle.

An example of forming a 0.3 μm-wide metal wiring on a semiconductor substrate by the lift-off method according to the present embodiment will be described with reference to FIGS. 9 and 10. Here, FIG. 9 and FIG. 10 are a top view and a side view, respectively, showing an automatic rotation type nozzle used in the lift-off method according to the present embodiment. In addition, the process cross-sectional views for explaining the lift-off method according to the present embodiment are basically the same as those in FIGS. Is used as is.

First, an organic film removing apparatus used for carrying out the lift-off method according to the present embodiment will be described with reference to FIGS.
Explanation will be made using 0. In this organic film removing device,
A stage (not shown) for mounting the Si wafer 10 is installed in the chamber (not shown).
Above the stage, a hollow pipe 40 having a diameter of, for example, 20 mmφ, to which high-pressure gas, liquid, or CO _{2 in} a mixed state of gas and liquid is supplied.
The hollow pipe 40 can rotate on a rotation axis 42 perpendicular to the surface of the Si wafer 10 mounted on the stage. A cross-shaped guide 44 extending in four directions parallel to the surface of the Si wafer 10 mounted on the stage is connected to the lower end of the pipe 40. The length of the guide 44 is 90 mm along the cross-shaped guide 44. Are arranged. The ejection ports of the plurality of nozzles 46 are connected to the Si mounted on the stage.
It is oriented, for example, at 5 ° from the direction of the rotation axis 42 perpendicular to the surface of the wafer 10.

Therefore, the high-pressure gas, liquid, and the like supplied to the plurality of nozzles 46 through the pipe 40 and the guide 44
Alternatively, when CO _{2 in} a mixed state of gas and liquid is blown out from the jet port, it is cooled by adiabatic expansion at that time,
Dry ice particles are easily formed. At this time, as indicated by small arrows in FIGS. 9 and 10,
When the ejection 48 of the dry ice particles is performed obliquely downward at a high speed from the ejection outlets of the plurality of nozzles 46, the plurality of nozzles 46, the guide 44, and the pipe 40 are rotated by the reaction of the ejection of the dry ice particles. Figure 9 around
And in the rotation direction indicated by the large arrow in FIG. That is, the plurality of nozzles 46 are installed above the stage so as to automatically rotate with the ejection of dry ice particles from the ejection ports.

Next, an example of forming a 0.3 μm-wide metal wiring on the Si wafer 10 by the lift-off method according to the present embodiment will be described. As in the case of the first embodiment, after applying a photoresist having a thickness of 8.0 μm on a Si wafer 10 as a semiconductor substrate, the photoresist is patterned into a predetermined shape using a photolithography technique. , A photoresist 12 of a lift-off pattern having a linear opening having a width necessary for forming a metal wiring having a width of 0.3 μm is formed so that its cross section has an inversely tapered shape.

Subsequently, using a vacuum evaporation machine, a film thickness of 10 n
A Ti / Au metal film for metal wiring, in which a Ti film of m and a 490 nm-thick Au film are sequentially laminated, is deposited, and a Ti / Au metal film 14a is deposited directly on the Si wafer 10; A Ti / Au metal film 14b is deposited thereon. At this time, similarly to the case of the first embodiment, the Ti / Au metal film 14c is also formed on the side wall of the photoresist 12 of the lift-off pattern by the Ti / Au metal film 14a.
Is formed in a state connected to.

Subsequently, the photoresist 12 and the like on the Si wafer 10 are removed by using the organic film removing apparatus already described with reference to FIGS. That is, the Si wafer 10 is mounted on a stage (not shown) provided in a chamber (not shown) of the organic film removing apparatus. Then, the pipe 4 is connected to the plurality of nozzles 46 installed above the stage.
0 and a high pressure gas, liquid or a mixture of gas and liquid CO ₂ is supplied through the guide 44, and the dry ice particles are ejected from the ejection port, and the plurality of nozzles 46 are rotated by the reaction of the ejection. Let it. Thus, the dry ice particles ejected from the ejection ports of the plurality of nozzles 46 that automatically rotate are sprayed on the surface of the Si wafer 10 while performing spiral movement.

At this time, the size of the dry ice particles spouted from the spouts of the plurality of nozzles 46 is controlled by the size of the spout, and the blowing speed of the dry ice particles is controlled by the spout. The blowing speed of CO _{2 in} a gas, a liquid, or a mixed state of gas and liquid is controlled by the pressure of CO ₂ supplied to the plurality of nozzles 46.

In this manner, by spraying high-speed dry ice particles from a plurality of nozzles 46 that automatically rotate onto the surface of the Si wafer 10, the Si wafer 1 is sprayed.
0 along with the photoresist 12 of the lift-off pattern on the Ti / Au metal film 14b on the photoresist 12.
Then, the Ti / Au metal film 14c on the side wall is removed. As a result, the Ti / Au metal film 14 is formed on the Si wafer 10.
a remains in the wiring pattern having a width of 0.3 μm.
0.3 μm wide Ti / A made of i / Au metal film 14a
u metal wiring 18 is formed.

As described above, according to the present embodiment, the Ti / Au metal film 14b and the Ti / A on the side wall of the photoresist 12 of the lift-off pattern on the Si wafer 10 are sprayed by high-speed spraying of dry ice particles.
By removing the u metal film 14c, the same effect as in the first embodiment can be obtained.

Further, according to the present embodiment, the dry ice particles ejected from the plurality of nozzles 46 that automatically rotate are sprayed on the surface of the Si wafer 10 while performing a spiral motion. The dry ice particles are sprayed on the surface of the Si wafer 10 from various angles, and the incident angle of the lift-off pattern on the Therefore, the ability to remove the photoresist 12 and the like is strengthened, and the photoresist 12 of the lift-off pattern, the Ti / Au metal film 14b thereon and the Ti / Au metal on the side wall thereof are extremely effectively and reliably. The film 14c can be removed. Therefore, the reliability in forming the fine pattern Ti / Au metal wiring 18 with high accuracy can be further enhanced as compared with the case of the first embodiment.

Further, since the rotation of the plurality of nozzles 46 is induced by the reaction of the ejection of the dry ice particles, no special power is required for the rotation, so that the organic film removing apparatus is simplified. , Its operating cost can also be reduced.

In the third embodiment, a plurality of automatically rotating nozzles 46 are used instead of the fixed nozzles in the lift-off method according to the first embodiment. Instead of the fixed nozzle in the lift-off method according to the second embodiment, a plurality of automatically rotating nozzles 46 may be used. That is, when the dry ice particles ejected from the plurality of nozzles 46 that automatically rotate are sprayed onto the surface of the Si wafer 10 while performing a spiral motion, irradiation with UV rays may be performed in an O ₃ atmosphere. In this case, since the effect of removing the resist and the like by the irradiation of O ₃ and UV rays is added, it is possible to further enhance the certainty in accurately forming the fine pattern Ti / Au metal wiring.

In the first to third embodiments, the dry particles which are solid CO ₂ as solid particles sprayed to remove the photoresists 12, 22 and the like of the lift-off pattern on the Si wafers 10, 20 are used. Although the case where ice particles are used has been described, substantially the same effects can be obtained by using solid H ₂ O ice particles instead of the dry ice particles.

The case where the Ti / Au metal wirings 18 and 34 of a predetermined pattern are formed directly on the Si wafers 10 and 20 has been described. However, the type of the semiconductor substrate and the metal wiring used here, The structure of the base, the film thickness, and other numerical values are not limited to these specific examples at all, and can be changed without departing from the gist of the present invention. Also, for a nozzle for spraying dry ice particles, numerical values such as the length and the inclination angle with respect to the surface of the Si wafer are not limited to these specific examples at all, and naturally, unless departing from the gist of the present invention. Can be changed.

[0059]

As described above, according to the lift-off method and the organic film removing apparatus of the present invention, the following effects can be obtained. That is, according to the lift-off method according to claim 1, when removing the metal film on the organic film together with the organic film patterned on the substrate, a fine pattern is obtained by using a technique of spraying solid particles. In addition, the organic film and the metal film thereon can be reliably removed. Further, even if a metal film is formed on the side wall of the organic film patterned on the substrate, the metal film on the side wall can be easily removed together with the organic film by high-speed spraying of solid particles. It is possible to prevent the metal film on the side wall of the resist from adhering as "burrs" when forming a predetermined pattern made of the metal film. Furthermore, the organic film removed by the high-speed spraying of solid particles and the metal film thereon are washed away by a strong flow of solid particles, so that the film pieces of the organic film and the metal film once lifted off are re-attached to the substrate surface. Can be prevented. In this way, a fine pattern made of a predetermined metal film can be formed with high certainty while preventing the occurrence of characteristic defects and a decrease in reliability due to the reattachment of the film pieces of the lifted-off organic film or metal film and the occurrence of "burrs". Can be formed.

According to the lift-off method of the second aspect, when the solid particles are sprayed on the entire surface of the substrate, the solid particles are sprayed in an O ₃ atmosphere, thereby removing organic substances by spraying the solid particles. In addition, since the organic substance removing effect of O ₃ is added and the organic substance removing ability is enhanced, even if the organic film has a fine pattern, the organic film and the metal film thereon can be more reliably removed.

According to the lift-off method of the third aspect, when the solid particles are sprayed on the entire surface of the substrate, the solid particles are sprayed while irradiating the entire surface of the substrate with UV rays in an O ₃ atmosphere. The effect of removing organic matter by spraying particles is combined with the effect of removing organic matter by O ₃ and the effect of removing organic matter by UV rays,
Since the ability to remove organic substances is further enhanced, even if the organic film has a fine pattern, the organic film and the metal film thereon can be removed even more reliably.

According to the lift-off method of the fourth aspect, the gas, the liquid, or the mixture of the gas and the liquid is blown out from the nozzle, and cooled by adiabatic expansion at that time to form solid particles, whereby the substrate is formed. For example, solid particles such as dry ice or ice particles for removing organic substances by spraying over the entire surface can be easily obtained.

According to the organic film removing apparatus of the present invention, since a plurality of nozzles for ejecting solid particles are provided above the stage on which the substrate is mounted, the solid particles can be ejected from the plurality of nozzles. Since it is possible to remove the organic film of a predetermined pattern formed on the substrate by spraying the entire surface of the upper substrate, even in the case of a fine pattern, it is ensured that the organic film and the metal film thereon and The metal film on the side wall can be removed.

According to the organic film removing apparatus of the eighth aspect, the ejection ports of the plurality of nozzles are oriented in a direction inclined from a direction perpendicular to the surface of the substrate mounted on the stage, and the stage moves the substrate. By mounting and rotating, solid particles ejected from a plurality of nozzles are obliquely sprayed onto the organic film of a predetermined pattern formed on the substrate, so that the organic film and the metal film thereon and the metal film thereon The metal film on the side wall can be easily removed, and the substrate mounted on the stage rotates at that time, so that the effect of removing the organic film and the like can be exerted uniformly on the entire surface of the substrate.

According to the organic film removing apparatus of the ninth aspect, the plurality of nozzles rotate above the stage, so that the solid particles ejected from the plurality of rotating nozzles move in a spiral motion over the entire surface of the substrate. Since the solid particles are sprayed, the solid particles are sprayed on the entire surface of the substrate from various angles, so that the organic film, the metal film thereon, and the metal film on the side wall thereof can be uniformly and extremely effectively removed over the entire surface of the substrate.

Further, according to the organic film removing apparatus of the tenth aspect, the plurality of nozzles are rotated by the rotation of the plurality of nozzles induced by the reaction when the solid particles are ejected from the plurality of nozzles. Since no special power is required, the apparatus can be simplified and its operating cost can be reduced.

As described above, by using the lift-off method and the organic film removing apparatus according to the present invention, it is possible to reliably and efficiently execute the lift-off method in the process of manufacturing a semiconductor device. Further, the object to which the lift-off method is applied can be expanded.

[Brief description of the drawings]

FIG. 1 is a process sectional view (part 1) for describing a lift-off method according to a first embodiment of the present invention.

FIG. 2 is a process sectional view (part 2) for explaining the lift-off method according to the first embodiment of the present invention.

FIG. 3 is a process sectional view (part 3) for describing the lift-off method according to the first embodiment of the present invention.

FIG. 4 is a process sectional view (part 4) for describing the lift-off method according to the first embodiment of the present invention.

FIG. 5 is a process sectional view (part 1) for explaining a lift-off method according to the second embodiment of the present invention.

FIG. 6 is a process sectional view (part 2) for describing the lift-off method according to the second embodiment of the present invention.

FIG. 7 is a process sectional view (part 3) for describing the lift-off method according to the second embodiment of the present invention.

FIG. 8 is a process sectional view (part 4) for describing the lift-off method according to the second embodiment of the present invention.

FIG. 9 is a top view showing an automatic rotation type nozzle used in a lift-off method according to a third embodiment of the present invention.

FIG. 10 is a side view showing an automatic rotation type nozzle used in a lift-off method according to a third embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 10: Si wafer, 12: photoresist of lift-off pattern, 14a, 14b, 14c: Ti / Au metal film, 16: spraying of dry ice particles, 18: Ti
/ Au metal wiring, 20: Si wafer, 22: photoresist of lift-off pattern, 24a, 24b, 24
c: Ti / Au metal film, 26: chamber, 28: O ₃ atmosphere, 30: irradiation of UV rays, 32: spraying of dry ice particles, 34: Ti / Au metal wiring, 40: hollow pipe, 42: rotation Shaft, 44 guide, 46 nozzle, 4
8 ... Emission of dry ice particles.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4M104 BB09 BB14 DD52 DD68 DD75 FF08 FF16 HH14 5F004 AA09 BB02 CA02 DA00 DA27 DB08 DB26 5F033 AA03 AA05 AA25 AA57 AA71 BA15 BA16 BA38 EA29

Claims (10)

[Claims] A first step of depositing a predetermined metal film on the entire surface of the substrate after patterning the organic film applied on the substrate into a predetermined shape; A second step of removing the metal film on the organic film, wherein a predetermined pattern made of the metal film is formed on the substrate. 2. The lift-off method according to claim 1, wherein the solid particles are sprayed in an ozone atmosphere when the solid particles are sprayed on the entire surface of the substrate. 3. The lift-off method according to claim 2, wherein when the solid particles are sprayed on the entire surface of the substrate, the solid particles are sprayed while irradiating the entire surface of the substrate with ultraviolet rays. 4. The lift-off method according to claim 1, wherein the solid particles are formed by blowing out a gas, a liquid, or a mixture of a gas and a liquid from a nozzle, and cooling by adiabatic expansion at that time. How to lift off. 5. The lift-off method according to claim 1, wherein the solid particles are dry ice particles. 6. The lift-off method according to claim 1, wherein the solid particles are ice particles. 7. A stage on which a substrate is mounted, and a plurality of components which are installed above the stage and which blow out a gas, a liquid, or a mixture of a gas and a liquid, and which are cooled by adiabatic expansion at that time to form and eject solid particles. And spraying the solid particles ejected from the plurality of nozzles on the entire surface of the substrate mounted on the stage, and the organic film having a predetermined pattern formed on the substrate on the organic film. An organic film removing apparatus for removing a predetermined metal film deposited on a substrate. 8. The organic film removing apparatus according to claim 7, wherein the ejection ports of the plurality of nozzles face a direction inclined from a direction perpendicular to a surface of the substrate mounted on the stage, and the stage Wherein the substrate is mounted and rotated. 9. The organic film removing apparatus according to claim 7, wherein the plurality of nozzles rotate above the stage. 10. The organic film removing apparatus according to claim 9, wherein the rotation of the plurality of nozzles is induced by a reaction when the solid particles are ejected from the plurality of nozzles. apparatus.