JPH0645247A - Method for patterning polyamide film and method for manufacturing semiconductor device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] A method for patterning a polyamide film that solves the problem of adverse effects of scum after resist development and removal when patterning a polyamide film, and a method for patterning such a polyamide film. Provided is a method for manufacturing a used semiconductor device. A method for patterning a polyamide film in which a polyamide film 4 formed on a substrate 1 is patterned using a resist 5, the resist is removed, and then treated with an inorganic acid such as fuming nitric acid. The polyamide film 4 formed on the substrate 1
A method for patterning a polyamide film, which comprises patterning using a resist 5 and removing the resist using an inorganic acid. A method for manufacturing a semiconductor device using the above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for patterning a polyamide film and a method for manufacturing a semiconductor device having a patterning step for a polyamide film. INDUSTRIAL APPLICABILITY The present invention can be used when forming various polyamide film patterns (for example, when forming a polyamide film pattern for forming a polyimide film pattern by a treatment such as firing), and a semiconductor that requires such pattern formation. It can be used when manufacturing the device.

[0002]

2. Description of the Related Art Conventionally, a polyimide film has been used as a protective film for a semiconductor device or the like. Since a polyimide film is generally formed by baking a polyamide film to form a polyimide film, the polyamide film is formed on a substrate, patterned, and then baked.

Such patterning is performed by a resist process. Conventionally, an N-butyl acetate solution has been widely used for resist stripping after coating / patterning (window opening) for forming a polyimide film. That is, in the conventional process, for example, in many cases, resist / developer /
The polyamic acid / N-2 methylpyrrolidone (solvent for polyamic acid) / N-butyl acetate system was used. However, in the conventional technique, a residue called "scum" remains. It is considered that this occurs as a chemical reaction product between these chemicals containing a polyamide film (which becomes a polyimide film after firing) as a main component. The reaction product between the resist and the polyamide is considered to be promising, but the details are still unknown, and this scum is at least insoluble in N-butyl acetate.

The conventional process shown in FIG. 3 will be described. As shown in FIG. 3A, the passivation film 3 (S) patterned on the metal 2 portion such as Al wiring on the substrate 1 is patterned.
iN, etc.), and a polyamide film is formed on this and patterned, first, the polyamide film 4 is formed on the entire surface (FIG. 3B), and a resist is applied, exposed and developed to form a resist pattern. 5 is formed (FIG. 3C), and the polyamide film 4 is patterned using the resist 5 as a mask (the polyamide film after patterning is shown by 40). As a result, the structure shown in FIG. 3D is obtained, but at this time, scum which is considered to have been generated during the resist development is attached, which cannot be found from above. The resist 5 is removed with N-butyl acetate as shown in FIG. 3 (e), but the scum is not dissolved and removed therein, and the scum remains as shown by 7 in FIG.

If such a scum 7 (reaction product) remains on the metal 2 forming the bonding pad as shown in FIG. 3 (e), a defect that a gold ball for bonding is not attached may occur. Alternatively, deterioration of ball shear strength (bonding strength of gold balls) becomes a problem.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a method for patterning a polyamide film, which solves the problem of adverse effects due to scum. The present invention is intended to provide a method for manufacturing a semiconductor device.

[0007]

The invention according to claim 1 of the present application is characterized in that a polyamide film formed on a substrate is patterned using a resist, and after the resist is removed, it is treated with an inorganic acid. A method for patterning a polyamide film, which achieves the above object.

The invention of claim 2 of the present application is the method for patterning a polyamide film according to claim 1, characterized in that fuming nitric acid is used as the inorganic acid, and thereby the above object is achieved. is there.

The invention of claim 3 of the present application is a method for patterning a polyamide film, which comprises patterning a polyamide film formed on a substrate with a resist and removing the resist with an inorganic acid. This achieves the above-mentioned object.

The invention according to claim 4 of the present application is the method for patterning a polyamide film according to claim 3, characterized in that fuming nitric acid is used as the inorganic acid, thereby achieving the above object. is there.

The invention of claim 5 of the present application is a method for manufacturing a semiconductor device, which comprises a step of patterning a polyamide film formed on a substrate by using a resist, and has a step of treating with an inorganic acid. A method of manufacturing a semiconductor device, which achieves the above object.

The invention according to claim 6 of the present application is the method for manufacturing a semiconductor device according to claim 5, wherein the treatment with the inorganic acid is a resist removal treatment and / or a scum removal treatment after the resist removal. Therefore, this achieves the above object.

[0013]

According to the invention of the present application, since a polyamide film is treated with an inorganic acid, scum generated during resist development is removed by the treatment with this inorganic acid. Therefore, the problem of the adverse effect of scum can be solved.

Further, if the resist removal itself is performed with an inorganic acid, the scum removal can be continuously achieved with this inorganic acid,
Efficient operation can be realized.

When fuming nitric acid is used as the inorganic acid,
Even if a metal (for example, Al bonding pad) is present on the substrate to be processed, it is possible to prevent the metal from being corroded by an acid and perform scum removal.

When no metal is present in the base, concentrated nitric acid and other inorganic acids such as mineral acids can be used appropriately. The case where there is no metal in the base is, for example, when opening a fuse for operating a redundant circuit (a spare circuit for repair) of a memory device or the like. Generally, there is no metal in this base. Therefore, the inorganic acid can be selected without considering the problem of metal corrosion.

[0017]

Embodiments of the invention of the present application will be described below with reference to the drawings. However, as a matter of course, each invention is not limited to the embodiments described below.

Example 1 In this example, the invention of claim 1 of the present application is applied to the manufacture of a semiconductor device having a polyamide film.
This will be described with reference to FIG.

An element is previously formed on the Si substrate 1, Al-based metals are formed as bonding pads (this metal is shown by reference numeral 2), and then a SiN-based passivation film 3 is formed. FIG. 1A shows a state after the passivation film 3 is opened.

Then, a polyamide film 4 (which becomes a polyimide film after baking at about 350 ° C. for about 60 minutes) is spin-coated to a thickness of about 7 μm, and prebaked using a hot plate or the like. The baking conditions at that time are 130 to 150 ° C. and 1
~ 2 minutes. The state after prebaking is shown in FIG.

After that, a resist is spin coated on the polyamide film 4 and exposed and developed. The resist coating conditions are
Film thickness 0.7-2 μm, prebaking 90-120 ° C, 1-
2 minutes. The exposure can be arbitrarily selected according to the characteristics of the resist, but it may be about 120 mJ / cm ² . The development is of the paddle type, and a developer having a TMAH concentration of 2.38% is used. The state after development is shown in FIG. 1C, and the formed patterned resist is indicated by reference numeral 5.

Scum (reaction product) which becomes a problem after development
6 is generated and adheres. FIG. 1D shows a state in which the polyamide film 4 is etched continuously with the resist development (the polyamide film 4 can be etched with a resist developing solution).
However, etching may be performed in another process using another liquid)
However, at this time, the scum 6 is not found even when observed from above in the state of FIG. 1 (d), and it can be found only when the resist 5 is released after being peeled off and redeposited. That is, FIG.
As indicated by reference numeral 7 in (e), the scum 6 (see FIG.
(D) is redeposited on the bonding pad metal 2.

Conventionally, N-butyl acetate solution has been widely used for stripping the resist 5. However, this solution cannot dissolve or remove the scum 6 or 7.

Therefore, in this embodiment, after the resist is removed, fuming nitric acid is used as the inorganic acid to treat the scum 7.
Was removed.

That is, as shown in FIG. 1 (e), fuming nitric acid was used in the state where the scum 7 was adhered, and as shown in FIG. 1 (f), a structure without scum adhesion was obtained. Base metal 2 (A
l) is not affected by fuming nitric acid and has no effect.

The method for removing the resist 5 with fuming nitric acid is as follows.
It is optional, and there is no problem with either paddle type or dip type. For example, specifically, it can be implemented as follows.

A substrate wafer is transferred onto a paddle type wafer chuck and vacuum-adsorbed. Fuming nitric acid is discharged onto the wafer through a nozzle.
At that time, if the wafer is rotated at a low speed so that the liquid is not shaken off, the peeling effect is enhanced. Next, shake off at high rotation,
Pure water is supplied from the nozzle and rinsed. Then spin dry. Equipment that can be used for treatment with hazardous substances such as fuming nitric acid is commercially available.

Dip type Fuming nitric acid is put in a chemical bath in advance, and the wafer together with the carrier is immersed therein. The material of the carrier needs to have high chemical resistance, and for example, a Teflon resin can be used, but quartz is preferable. After that, the carrier is transferred to a water washing tank and washed with water. Drying
When using a commercially available spin dryer or a quartz carrier, an IPA vapor dryer may be used.

In this embodiment, elements are formed on the Si substrate 1 in advance, the passivation film 3 is molded with a SiN-based film, and then a polyimide-based organic film for relaxing stress from the molding resin of the IC package is formed. When doing
After peeling the resist 5 after coating and opening the window, the fuming nitric acid is used, and the paddle method or the dip method is used in the batch method. After that, in the paddle method, pure water is discharged from the nozzle while rotating the wafer, and washed. Dried again
In the dip method, the wafer carrier was transferred to a pure water tank, washed with water, and then dried. As a result, the scum can be removed easily and surely, and defects due to the scum can be prevented.

The polyamide film 4 was patterned as described above, and when a semiconductor device having a polyimide film was manufactured by using the patterning, the defect rate could be reduced.

Example 2 In this example, fuming nitric acid was used for resist stripping itself, and scum removal was performed continuously with resist stripping. Please refer to FIG.

Up to FIGS. 2A to 2D, the same operation as in FIGS. 1A to 1D of Example 1 was performed.

In the state of FIG. 2D (the state after the resist has been stripped), the resist 5 is made of fuming nitric acid. This process may be performed in the same manner as in Example 1, and may be a paddle type or a dip type.

As a result, the peeling of the resist 5 and the removal of the scum 6 were continuously performed, and a scum-free structure was obtained as shown in FIG. 2 (E).

Since fuming nitric acid has the effect of dissolving scum and the resist, fuming nitric acid was used as the resist stripping solution in this example, whereby the generated scum could be removed at the same time.

[0036]

According to the present invention, it is possible to provide a method for patterning a polyamide film, which solves the problem of adverse effects of scum. Further, even when the method includes the patterning step of the polyamide film, it is possible to provide a method for manufacturing a semiconductor device that solves the problem of adverse effects of scum.

[Brief description of drawings]

1A to 1C are sectional views showing steps of a first embodiment in order.

2A to 2C are cross-sectional views showing steps of Example 2 in order.

FIG. 3 is a sectional view showing the steps of a conventional example in order.

[Explanation of symbols]

 1 substrate 2 passivation film 3 metal (pad Al) 4 polyamide film 40 patterned polyamide film 5 resist 6 and 7 scum

Claims (6)

[Claims] 1. A method for patterning a polyamide film, which comprises patterning a polyamide film formed on a substrate with a resist, removing the resist, and then treating with an inorganic acid. 2. The method for patterning a polyamide film according to claim 1, wherein fuming nitric acid is used as the inorganic acid. 3. A method for patterning a polyamide film, which comprises patterning a polyamide film formed on a substrate with a resist and removing the resist with an inorganic acid. 4. The method for patterning a polyamide film according to claim 3, wherein fuming nitric acid is used as the inorganic acid. 5. A method of manufacturing a semiconductor device, comprising a step of patterning a polyamide film formed on a substrate using a resist, the method including the step of treating with a mineral acid. 6. The method for manufacturing a semiconductor device according to claim 5, wherein the treatment with the inorganic acid is a resist removal treatment and / or a scum removal treatment after the resist removal.