JP2002214801A - Developing solution for photosensitive polyimide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive polyimide developing solution, having satisfactory solvent power and which will not cause cracks to resin, after development while minimizing a bipolar aprotic solvent whose toxicity has been pointed out. SOLUTION: The photosensitive polyimide developing solution contains a cyclic ketone compound and water as essential components and the content of a bipolar aprotic solvent in the developing solution is <=1% of the total weight of the developing solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semiconductor device.
The present invention relates to a photosensitive polyimide developer useful for producing electric and electronic materials such as a multilayer wiring board.

[0002]

2. Description of the Related Art Polyimide has excellent heat resistance, electrical properties, and mechanical properties.
It is widely used as an interlayer insulating film of a multilayer wiring board, a stress buffer coat, and the like. Further, since photosensitive polyimide itself has pattern processing properties, the process can be simplified as compared with the case where pattern processing is performed on ordinary non-photosensitive polyimide using a resist or the like.

As a developer used for patterning photosensitive polyimide, an organic developer-based developer is mainly used. For example, 1) N-methyl-2-
A solution obtained by adding water to a dipolar aprotic solvent such as pyrrolidone (JP-A-58-66940), 2) A dipolar aprotic solvent such as N-methyl-2-pyrrolidone and a poor solvent such as methanol. 3) Addition of lower alcohol (JP-A-58-223149), 3) Addition of aromatic hydrocarbon and water to a dipolar aprotic solvent such as N-methyl-2-pyrrolidone. 1330
No. 62), and 4) a dipolar aprotic solvent such as N-methyl-2-pyrrolidone to which an ester compound such as propylene carbonate or propylene glycol monomethyl ether acetate and water are added (Japanese Patent Application Laid-Open No. 7-27105).
No. 3) are used, but all contain a dipolar aprotic solvent as an essential component for the purpose of ensuring sufficient solubility. However, in recent years, concerns about the harmfulness of these bipolar aprotic solvents to the human body have been increasing, and as a developer for photosensitive polyimide,
There is a demand for a solvent that uses as little as possible of these dipolar aprotic solvents.

Some developers which do not use a dipolar aprotic solvent use cyclohexanone or cyclopentanone, but these have problems such as insufficient solubility or cracking after development. Was.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, the present invention uses a dipolar aprotic solvent, which has been pointed out as harmful, as much as possible and has sufficient dissolving power. Still another object of the present invention is to provide a photosensitive polyimide developer which does not cause cracks after resin development.

[0006]

The present invention employs the following means in order to solve the above-mentioned problems. That is, the developer for photosensitive polyimide of the present invention is a developer containing a cyclic ketone compound and water as essential components, and the content of the dipolar aprotic solvent in the developer is the total weight of the developer. Is 1% or less of the above.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention has been made to solve the above-mentioned problems, that is, to use a dipolar aprotic solvent which is pointed out as harmful as much as possible and to have sufficient dissolving power. The developer for photosensitive polyimide that does not generate, was studied diligently, as the developer, a cyclic ketone compound and water as essential components, and, when the content of the dipolar aprotic solvent was controlled as much as possible, It has been found that such a problem can be solved at once.

[0008] The polyimide developer of the present invention contains a cyclic ketone compound and water as essential components. As the cyclic ketone compound, cyclopentanone and cyclohexanone are preferably used, but are not limited thereto. The cyclic ketone may be only one kind or a mixture of several kinds of cyclic ketones.

The water contained in the developer of the present invention is effective in suppressing cracks and improving solubility. The content of water contained in the developing solution for polyimide of the present invention is preferably 0.1% to 10%, more preferably 0.1% to 5% of the total weight.
It is good. If the amount is less than this, cracks are likely to occur after development, and if it is more than this, the solubility is too strong, and problems such as swelling of the pattern after development or no formation of the pattern are likely to occur. In addition, the water contained in the developer of the present invention may not contain metal ions, chloride ions, and the like, such as ion-exchanged water and distilled water, due to the demand in the semiconductor field, which is a main use of photosensitive polyimide. preferable.

The cyclic ketone contained in the developer of the present invention is
Since the dissolving power of water is not so high, an excessive amount of water may cause phase separation. In particular, it should be noted that the solubility of water decreases as the number of cyclic ketone carbon atoms increases. When phase separation is caused, a highly polar organic compound such as alcohol or ester may be added. Examples of the alcohol include, but are not limited to, methanol, ethanol, propanol, isopropanol, butanol, ethylene glycol, and propylene glycol. Examples of the ester include, but are not limited to, propylene carbonate, propylene glycol monomethyl ether acetate, ethyl lactate, and butyl acetate. The content of these alcohols and esters is preferably 30% or less of the total weight. If it exceeds this, the solubility may be reduced.

Since the apolar aprotic solvent has been pointed out to be harmful to the human body, its content in the developing solution of the present invention is preferably 1% or less of the total weight. It is more preferably at most 0.5% of the total weight, most preferably at most 0.1% of the total weight. Examples of the dipolar aprotic solvent used herein include, but are not limited to, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, and the like.

As the photosensitive polyimide used in the developer of the present invention, a photosensitive polyimide precursor which can be converted into a polyimide by heat treatment is often used. For example, a polyimide precursor synthesized from an acid dianhydride and a diamine mixed with an amine compound having a photoreactive double bond, or a photoreactive double bond bonded to a polymer via an ester group A mixture obtained by mixing a (meth) acrylic monomer with a polyimide precursor is used, but is not limited thereto.

Next, a method for patterning a photosensitive polyimide composition using the developing solution of the present invention will be described.

First, the composition of the present invention is applied on a suitable substrate. Examples of the material of such a substrate include, but are not limited to, metals, glass, semiconductors, metal oxide insulating films, and silicon nitride. As an application method, means such as spin coating using a spinner, spray coating using a spray coater, dipping, printing, and roll coating can be adopted. Since the composition of the present invention has a viscosity as low as that of a photoresist, a spin coating device for a photoresist can be used as it is.

Next, the substrate coated with the polyimide precursor is dried to obtain a polyimide precursor composition film. For drying, use an oven, hot plate, infrared ray, etc.
Preferably 15 to 150 ° C, more preferably 40 to 10
It is good to carry out in the range of 0 ° C. The drying time is preferably from 10 seconds to several hours. If the film has already been dried immediately after the application, the drying step can be omitted.

Next, exposure is performed using a mask having a desired pattern. The exposure amount is preferably 50 to 1
000 mJ / cm ² , more preferably 100 to 600 m
The range of J / cm ² is good. By using an appropriate sensitizer, exposure can be performed using an exposure machine such as an i-line stepper, a g-line stepper, a mask aligner, and a mirror projection aligner.

The resolution of the pattern at the time of development is improved,
When the allowable range of the developing conditions is increased, a step of performing a baking process before the development may be adopted. The temperature is preferably in the range of 30 to 150C, more preferably 40 to 100C. The time is preferably from 10 seconds to several hours. If these conditions are not satisfied, the reaction may not proceed or all the regions may not be dissolved.

Next, a relief pattern is obtained by dissolving and removing the unirradiated portion with a developing solution. The development can be carried out by irradiating the above-mentioned developer onto the coating film surface as it is or in the form of a mist, immersing in the developer, or applying ultrasonic waves while immersing.

Next, it is preferable to wash the relief pattern formed by development using water or an organic solvent. Examples of the washing liquid include methanol, ethanol, isopropyl alcohol, ethyl lactate, ethyl pyruvate, propylene glycol monomethyl ether acetate, methyl-3-methoxypropionate, ethyl-3-ethoxypropionate, 2-heptanone, and ethyl acetate. It is preferably used.

The polymer of the relief pattern obtained by the above treatment is a precursor of a polyimide-based polymer having heat resistance, and becomes a heat-resistant polymer having an imide ring or other cyclic structure by heat treatment. The heat treatment temperature is preferably 200 to 500 ° C, more preferably 300 to 400 ° C. Such heat treatment
Preferably, it is carried out while increasing the temperature stepwise or continuously.

[0021]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Synthesis Example 1 In a 1-liter four-necked flask,
9.61 g of 4'-diaminodiphenyl ether (0.0
48 mol), 8.65 g (0.02 mol) of bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4
-(4-Aminophenoxy) phenyl] hexafluoropropane 10.37 (0.02 mol), 1.24 g of bis (3-aminopropyl) tetramethyldisiloxane
(0.005 mol) with N-methyl-2-pyrrolidone 10
It melt | dissolved in 6.48g at 40 degreeC. Thereafter, 6.54 g (0.03 mol) of pyromellitic anhydride, 3,3 ′, 4,
4'-benzophenonetetracarboxylic dianhydride 9.6
7 g (0.03 mol), 12.41 g of 3,3 ′, 4,4′-diphenylethertetracarboxylic dianhydride
(0.04 mol), N-methyl-2-pyrrolidone 30 g
Was added and reacted at 50 ° C. for 3 hours. After cooling to room temperature, dimethylformamide dimethyl acetal 29.7
After adding 7 g, the mixture was stirred at 40 ° C. for 2 hours. 1 L of this solution
The polymer was collected by filtration, washed three times with pure water, and then dried in a vacuum dryer at 80 ° C. for 24 hours. Of the polymer powder thus obtained, 26 g of cyclopentanone was used.
9 g and gamma-butyrolactone 11.1 g. Glycerol monomethacrylate 9.61
g, trimethylolpropane triacrylate 2.60
g, N-phenylglycine 0.54 g, 7-diethylamino-3-benzoylcoumarin 0.27 g, 1-nitroso-2-naphthol 0.02 g, acrylic surfactant (manufactured by Kusumoto Chemicals, Ltd .: "Dispalon" L) -1984)
0.02 g was added and stirred. This was designated as varnish A. Example 1 3 g of varnish A was dropped on a 4-inch silicon wafer and spin-coated for 30 seconds. Then, a 60 ° C hot plate (apparatus: SKW-63 manufactured by Dainippon Screen Mfg. Co., Ltd.) was used.
6) Baking for 3 minutes. At this time, the coating rotation was adjusted so that the film thickness after baking was about 8 μm. Next, exposure was performed using a mask aligner (PLA-501F manufactured by Canon Inc.). The exposure dose measured by i-line is 300 mJ / cm ²
Met.

After exposure, the film was developed with a developing solution consisting of 29% by weight of cyclopentanone, 50% by weight of cyclohexanone and 1% by weight of water, rinsed with propylene glycol monomethyl ether acetate, and dried.

As a result of observing the pattern after development, the film thickness retention ratio of the exposed portion was 92%, and a 10 μm pattern was resolved. No crack was generated after the development. Example 2 Pattern processing was performed in the same manner as in Example 1 except that a developer consisting of 99% by weight of cyclopentanone and 1% by weight of water was used. As a result of observing the pattern after development, the film thickness retention ratio of the exposed portion was 89%, and a 10 μm pattern was resolved. No crack was generated after the development. Example 3 Pattern processing was performed in the same manner as in Example 1 except that a developing solution consisting of 80% by weight of cyclohexanone, 10% by weight of isopropanol, and 10% by weight of water was used. As a result of observing the pattern after development, the film thickness retention ratio of the exposed portion was 87%, and a 10 μm pattern was resolved. No crack was generated after the development. Example 4 Pattern processing was carried out in the same manner as in Example 1 except that a developer consisting of 93% by weight of cyclohexanone, 5% by weight of isopropanol and 2% by weight of water was used. As a result of observing the pattern after development, the film thickness retention ratio of the exposed portion was 90%,
A 10 μm pattern was resolved. No crack was generated after the development. Comparative Example 1 Pattern processing was performed in the same manner as in Example 1 except that a developer consisting of only cyclopentanone was used. As a result of observing the pattern after the development, the film thickness retention ratio of the exposed portion was 92%, and the pattern of 10 μm was resolved, but cracks occurred after the development. Comparative Example 2 Pattern processing was performed in the same manner as in Example 1 except that a developing solution composed of cyclohexanone was used. As a result of observing the pattern after the development, the film thickness retention ratio of the exposed portion was 96%, but the developing time became longer due to insufficient dissolving power.
Also, cracks occurred after development. Comparative Example 3 Pattern processing was performed in the same manner as in Example 1 except that a developing solution composed of 20% by weight of cyclopentanone, 55% by weight of cyclohexanone, 10% by weight of isopropyl alcohol, and 15% by weight of water was used. As a result of observing the pattern after development, a 10 μm pattern was resolved at a film thickness retention ratio of 83% at the exposed portion, and no crack was generated after development.
Swelling of the pattern occurred severely. Comparative Example 4 Pattern processing was performed in the same manner as in Example 1 except that a developing solution consisting of 80% by weight of cyclopentanone, 5% by weight of isopropyl alcohol, and 15% by weight of water was used. As a result of observing the pattern after the development, the solubility of the developing solution was too strong, and the film thickness retention ratio of the exposed portion was only about 60%, and the pattern could not be formed.

[0025]

According to the present invention, it is possible to provide an excellent polyimide developer which is less harmful to the human body, has sufficient solubility, and is free from cracks after development.

Claims (3)

[Claims] 1. A developing solution containing a cyclic ketone compound and water as essential components, wherein the content of a dipolar aprotic solvent in the developing solution is 1% or less of the total weight of the developing solution. A developer for photosensitive polyimide, characterized by the following. 2. The developer according to claim 1, wherein the cyclic ketone compound is cyclopentanone and / or cyclohexanone. 3. The content of the water is 0.1% of the total weight of the developer.
The developer for photosensitive polyimide according to claim 1, wherein the amount is from 10% to 10%.