JP3141855B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device capable of forming a through hole by lithography.

[0002]

2. Description of the Related Art Conventional methods for manufacturing a semiconductor device in which ohmic electrodes and through holes are formed include lithography,
Each of the steps of etching and forming an interlayer insulating film is performed twice. 3A to 3E are cross-sectional views illustrating a conventional method for manufacturing a semiconductor device in the order of steps.

In a conventional semiconductor manufacturing apparatus, first,
As shown in FIG. 3A, an interlayer insulating film 131 is formed on the semiconductor substrate 111 on which the gate electrode pad 112 has been formed. Further, the photoresist 11 is formed on the interlayer insulating film 131.
5 is applied, and patterning is performed on a region where an ohmic electrode is to be formed by a known lithography technique.

Next, as shown in FIG. 3B, a region where the ohmic electrode is to be formed in the interlayer insulating film 131 is etched by wet etching to form an ohmic electrode, thereby exposing the semiconductor substrate 111.

Then, as shown in FIG. 3C, an ohmic metal 117 is deposited on the predetermined ohmic electrode region, and the ohmic metal 11 on the interlayer insulating film 131 is formed.
7 is subjected to a lift-off process together with the interlayer insulating film 131 to form an ohmic electrode.

Next, as shown in FIG. 3D, an interlayer insulating film 132 is again formed on the entire surface, a photoresist 133 is further applied, and the region on the gate electrode pad 112 and the ohmic contact are formed by a known lithography technique. A region on the metal 117 is patterned.

Finally, as shown in FIG. 3E, through holes 116 are formed by dry etching with a gas such as SF ₆ using the pattern of the photoresist 133 as a mask, and the photoresist 133 is peeled off.

[0008]

However, in the conventional method of manufacturing a semiconductor device configured as described above, each of the steps of lithography, etching, and formation of the interlayer insulating film is performed twice, so that the gate is not used. There is a problem that the number of steps after the formation of the electrode is large, and the cost of manufacturing the semiconductor device is increased.

The present invention has been made in view of such a problem, and the number of steps from the gate electrode formation to the through-hole formation step can be reduced, and the cost of manufacturing a semiconductor device can be reduced. It is an object to provide a method for manufacturing a semiconductor device.

[0010]

[0011]

According to a first method of manufacturing a semiconductor device according to the present invention, a step of forming a photosensitive organic film on a semiconductor substrate having a gate electrode pad formed thereon, Forming a light-shielding metal film on the entire surface; applying a photoresist on the entire surface of the light-shielding metal film; removing a region of the photoresist on the gate electrode pad and a region where an ohmic electrode is to be formed; Exposing the light-shielding metal film, exposing the photosensitive organic film by etching the light-shielding metal film, exposing the photosensitive organic film, and developing the photosensitive organic film through holes. Forming, forming a metal film for an electrode in the through hole, and performing a lift-off process on the metal film for an electrode on the photosensitive organic film.

According to a second method of manufacturing a semiconductor device according to the present invention, a step of forming a photosensitive organic film on a semiconductor substrate by removing a part thereof, a step of forming a gate metal on the entire surface, Providing a gate electrode pad on the gate metal on an unformed portion of the organic film, applying a first photoresist on the entire surface, and removing an ohmic electrode formation region of the first photoresist. Forming a gap below the resolution of the photosensitive organic film between the gate electrode pad and the first photoresist; and exposing the photosensitive organic film by etching the gate metal. Exposing the photosensitive organic film, developing the photosensitive organic film, applying a second photoresist over the entire surface, and forming an ohmic electrode of the second photoresist. Forming a through hole by removing a region to be formed, depositing an electrode metal film in the through hole, and performing a lift-off process on the electrode metal film on the photosensitive organic film. It is characterized by.

Preferably, the photosensitive organic film is a BCB film, and the step of exposing the photosensitive organic film may be performed by using an i-line of a mercury lamp.

Further, the metal film for an electrode may be made of an AuGeNi alloy, and the step of etching the gate metal to expose the photosensitive organic film may be a gas etching using SF ₆ .

In the present invention, three steps of a photoresist step, a wet wet etching step for forming a region where an ohmic electrode is to be formed, and a step of forming an interlayer insulating film for forming a through hole are omitted. As a result, the manufacturing process of the semiconductor device can be shortened, and the manufacturing cost can be reduced. Also, BC
Since the B film is a low dielectric material, the capacitance between wirings and the like can be reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a semiconductor device according to an embodiment of the present invention will be specifically described below with reference to the accompanying drawings. 1A to 1D are cross-sectional views illustrating a method of manufacturing a semiconductor device according to a first embodiment of the present invention in the order of steps.

In the method of manufacturing a semiconductor device according to the first embodiment of the present invention, first, as shown in FIG. 1A, a BCB is formed on a semiconductor substrate 11 on which a gate electrode pad 12 is formed.
A positive photosensitive organic film 13 made of a film or the like is applied to a thickness of about 5000 A by a spinner or the like, and a light-shielding metal film 14 is further formed thereon to a thickness of 250 A.

Next, as shown in FIG. 1B, a photoresist 15 is applied on the light-shielding metal film 14, and a region on the gate electrode pad 12 and a region where an ohmic electrode is to be formed are patterned by a known lithography technique. I do.

After that, as shown in FIG. 1C, the light shielding metal film 14 is etched by a known dry etching technique to expose the photosensitive organic film 13.

Next, as shown in FIG. 1D, the entire surface is exposed, the photosensitive organic film 13 exposed by the etching of the light-shielding metal film 14 is exposed, and a developing process is performed. A portion of the photosensitive organic film 13 is removed, and a through hole 16 is formed in a desired portion. Further, an ohmic metal 17 made of an AuGeNi alloy or the like is vapor-deposited in the through hole 16, and the ohmic metal 17 on the photosensitive organic film 13 is lifted off together with the photoresist 15. Can be formed.

In the method of manufacturing a semiconductor device according to the first embodiment of the present invention having the above-described structure, a photoresist coating process and a wet etching for forming an ohmic electrode are different from the conventional method of manufacturing a semiconductor device. The number of steps and the step of forming an interlayer insulating film for forming a through-hole can be reduced by one, that is, three steps in total.

As described above, in this embodiment, it is possible to shorten the steps of fabricating the semiconductor device and reduce the manufacturing cost. Further, by forming the photosensitive organic film 13 from a low dielectric material such as a BCB film, it is possible to reduce the capacitance between wirings and the like.

FIGS. 2A to 2E are sectional views showing a method of manufacturing a semiconductor device according to a second embodiment of the present invention in the order of steps.

In the method of manufacturing a semiconductor device according to the second embodiment of the present invention, first, as shown in FIG. 2A, a photosensitive organic film 13 is partially removed on a semiconductor substrate 11 as an interlayer insulating film. The gate metal 21 is further formed on the entire surface. The gate metal 21 also extends to a portion where the photosensitive organic film 13 is not formed. Further, there is provided a gate electrode pad 24 in which an Au plating 22 is formed on the gate metal 21 on a portion where the photosensitive organic film 13 is not formed. A photoresist 15 is applied on the entire surface, and patterning is performed on a region where an ohmic electrode is to be formed by a known lithography technique. At this time, a resist gap 2 having a PR of about 1 μm is formed between the gate electrode 24 and the photoresist 15 in the fold portion.
Keep 3 open.

Next, as shown in FIG. 2B, using the patterned photoresist 15 as a mask, the gate metal 21 is removed by dry etching with a gas such as SF ₆ to expose the photosensitive organic film 13. .

Thereafter, as shown in FIG. 2C, only the exposed photosensitive organic film 13 is exposed by exposing the entire surface to i-line of a mercury lamp. Further, the photosensitive organic film 13
When the photoresist 15 is peeled off by performing the developing process, a through hole 16 is opened. At this time, the photosensitive organic film 1
Since the resolution of No. 3 is 5 μm or more, the portion of the resist gap 23 of about 1 μm is not developed like the through hole 16 even if exposed.

Next, as shown in FIG. 2D, a photoresist 33 is applied again on the entire surface, patterning is performed on a region where an ohmic electrode is to be formed by a known lithography technique, and ohmic metal 17 is formed in the through hole 16. Is deposited.

Finally, as shown in FIG. 2E, the ohmic metal 17 on the photosensitive organic film 13 is
Together with 3, an ohmic electrode and a through hole 16 are formed by performing a lift-off process.

In the method of manufacturing the semiconductor device according to the second embodiment of the present invention, the gate metal 21
Where the conventional three lithography steps are required from the processing step to the formation step of the through hole 16, the lithography step can be performed by two lithography steps. Further, a wet etching step and an interlayer insulating film forming step for forming a through hole for forming an ohmic electrode can be reduced, and a total of three steps can be reduced.

As described above, in the present embodiment, it is possible to shorten the steps of fabricating the semiconductor device and to reduce the manufacturing cost. Further, by forming the photosensitive organic film 13 from a low dielectric material such as a BCB film, it is possible to reduce the capacitance between wirings and the like.

[0031]

As described in detail above, according to the present invention,
The manufacturing process of the semiconductor device can be shortened, and the manufacturing cost can be reduced. Further, since the BCB film is a low dielectric material, the capacitance between wirings and the like can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view illustrating a method for manufacturing a semiconductor device according to a first embodiment of the present invention in the order of steps.

FIG. 2 is a sectional view illustrating a method for manufacturing a semiconductor device according to a second embodiment of the present invention in the order of steps.

FIG. 3 is a cross-sectional view showing a conventional method of manufacturing a semiconductor device in the order of steps.

[Explanation of symbols]

 11, 111; semiconductor substrate 12, 24, 112; gate electrode pad 13; photosensitive organic film 14; light-shielding metal film 15, 33, 115, 133; photoresist 16, 116; through hole 17, 117; Gate metal 22; Au plating 23; resist spacing 131, 132; interlayer insulating film

Claims (6)

(57) [Claims] 1. A step of forming a photosensitive organic film on a semiconductor substrate on which a gate electrode pad is formed, a step of forming a light-shielding metal film over the entire surface of the photosensitive organic film, and a step of forming the light-shielding metal film. Applying a photoresist on the entire surface, removing the region of the photoresist on the gate electrode pad and the region where the ohmic electrode is to be formed to expose the light-shielding metal film, and etching the light-shielding metal film. A step of exposing the photosensitive organic film, a step of exposing the photosensitive organic film, a step of developing the photosensitive organic film to form a through hole, and depositing a metal film for an electrode in the through hole. A method for manufacturing a semiconductor device, comprising: a step of performing a lift-off process on a metal film for an electrode on the photosensitive organic film. 2. A step of forming a photosensitive organic film on a semiconductor substrate except for a part thereof, a step of forming a gate metal on the entire surface, and a step of forming a gate metal on an unformed portion of the photosensitive organic film. A step of providing a gate electrode pad, a step of applying a first photoresist on the entire surface, a step of removing an area where the ohmic electrode is to be formed in the first photoresist, and a step of removing the gate electrode pad and the first photoresist. Forming a gap smaller than or equal to the resolution of the photosensitive organic film, etching the gate metal to expose the photosensitive organic film, exposing the photosensitive organic film, Developing a conductive organic film, applying a second photoresist over the entire surface, and removing a region where the ohmic electrode is to be formed of the second photoresist to form a through hole. A step of depositing a metal film for an electrode in the through hole, and a step of lifting off the metal film for an electrode on the photosensitive organic film. Wherein the photosensitive organic film manufacturing method of a semiconductor device according to claim 1 or 2, characterized in that a BCB film. 4. The method according to claim 1, wherein the step of exposing the photosensitive organic film is performed by using an i-line of a mercury lamp.
The method of manufacturing a semiconductor device according to any one of 1 to 3. 5. A method of manufacturing a semiconductor device according to any one of claims 1 to 4 wherein the electrode metal film is characterized by comprising the AuGeNi alloy. 6. A process for exposing the etching said gate metal photosensitive organic film, any one of claims 2 to 5, characterized in that a gas etching using SF ₆
13. The method for manufacturing a semiconductor device according to item 9.