JP3432437B2 - Developing solution for positive photosensitive resin composition and pattern forming method using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing solution for a photosensitive resin composition for obtaining a high-resolution pattern with no development residue and a method for forming a pattern of a photosensitive resin composition using the same.

[0002]

2. Description of the Related Art In recent years, in the semiconductor industry, IC and LS
A photosensitive resin such as a photoresist or a photosensitive polyimide is often used for an insulating film or a protective film in a package that requires the formation or processing of an ultrafine circuit such as I. A characteristic of the photosensitive resin is that a highly accurate resin pattern can be obtained with a relatively simple device. In particular, a positive photoresist based on a phenol novolac resin using diazoquinone or the like as a photosensitizer does not cause swelling during development, and thus a pattern having excellent resolution can be formed. Further, since the developing solution is an alkaline aqueous solution, it has a number of features that it is excellent in terms of safety, and is therefore widely used in the production of the above-mentioned semiconductor fine circuits.

On the other hand, even in a photosensitive heat-resistant resin such as photosensitive polyimide used for an insulating film or a protective film of a semiconductor,
A positive type photosensitive heat-resistant resin having characteristics such as high resolution and no pollution of a developing solution has been developed in the same manner as a photoresist (see, for example, JP-A-64-60630, Japanese Patent Publication No.
No. 46862), it is attracting attention as a highly integrated resin for insulating films and protective films of semiconductors.

Most positive-working photosensitive resin compositions consist of combining an alkali-soluble polymer with a diazoquinone compound as described above as a photosensitizer. In the unexposed area, these diazoquinone compounds are insoluble in the alkaline aqueous solution, but undergo a chemical change upon exposure and become soluble in the alkaline aqueous solution. Therefore, by utilizing this difference in solubility between exposed and unexposed areas and removing the exposed areas with an alkaline aqueous solution, it becomes possible to create a coating film pattern only in the unexposed areas.

The alkaline aqueous solution used as the developing solution is generally an aqueous solution of tetramethylammonium hydroxide (hereinafter referred to as TMAH). When developing a photoresist based on an ordinary phenol novolac resin, it can be well developed with this aqueous solution of TMAH. For example, a polybenzoxazole precursor as disclosed in JP-B-1-46862 is used as a base. In the case of the photosensitive resin composition described above, there is a drawback that the undeveloped portion (scum) is generated in the exposed portion which should be completely dissolved and removed, and the resolution is deteriorated.

As is well known, the characteristics of evaluating these photosensitive resins are sensitivity (how much a pattern can be formed with a small amount of exposure energy), resolution (how fine a pattern can be formed). And contrast (how large the difference in solubility between the exposed and unexposed areas in the developing solution) is. Focusing on this contrast here, in this photosensitive system, the base polymer itself is soluble in an alkaline solution regardless of exposure / non-exposure, so that the unexposed portion is also dissolved during development. Therefore, in the conventional development using an alkaline developing solution, the film thickness of the unexposed portion was reduced, and good contrast could not be obtained.

In order to improve this drawback, a method is known in which a solubility control agent such as a heterocyclic compound or a cyclic acid anhydride is added to the photosensitive resin composition to suppress the solubility of the resin. JP-A-48-12242, JP-B-56-30
850). However, these additives remain in the resin even after development. Therefore, the heat resistance and mechanical performance of the photosensitive resin are lowered by these additives, making it difficult to use the photosensitive resin in applications such as semiconductor insulating films. Further, when a developer for a photosensitive resin as disclosed in JP-A-3-104053 is used, the film reduction rate is improved, but there is a problem that the sensitivity and resolution are lowered.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a developer for a photosensitive resin composition and a photosensitive resin composition which are not only excellent in sensitivity and film reduction rate but also eliminate scum in the pattern processing step and obtain high resolution. A method for forming a pattern of an object is provided.

[0009]

The present invention is a developer for a positive photosensitive resin composition comprising an anionic surfactant and an alkaline aqueous solution containing an extremely small amount of chlorine, and a positive photosensitive material using the same. The method for forming a pattern of a functional resin composition.

Further, the anionic surfactant preferably has a structure represented by the following formula (1).

[Chemical 3] A polyamide represented by the following formula (2),

[Chemical 4] A positive photosensitive resin composition consisting of a diazoquinone compound is applied to a substrate, prebaked, irradiated with light, and then exposed with a developing solution consisting of an alkaline aqueous solution containing an anionic surfactant and a trace amount of chlorine. Is a method of forming a pattern of a photosensitive resin composition by dissolving and removing the. The content of the anionic surfactant is 0.1
10 to 10% by weight, and the concentration of chlorine is 2 to 200 ppm
Is.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The polyamide of the formula (2) comprises bisaminophenol having a structure of X and dicarboxylic acid having a structure of Y.
When it is heated at 0 ° C., the ring is closed and changed into a heat resistant resin called polybenzoxazole. Generally, a positive photosensitive resin composition is developed with an aqueous alkaline solution. For example, a photoresist can be developed because the base phenol novolac resin has a phenolic hydroxyl group. Similarly, the positive photosensitive resin based on the polyamide represented by the formula (2) can be developed by the phenolic hydroxyl group in the bisaminophenol having the structure of X, but the photoresist based on the phenol novolac resin is used. As a result, the developability is poor and scum is generated in the exposed area, resulting in poor resolution.

It is considered that this is because in the polyamide represented by the formula (2), the hydroxyl group is the only amine component in the phenol novolac resin containing one hydroxyl group per one benzene ring. A polyamide in which a part of the bisaminophenol having the structure of X is replaced with a silicone diamine having the structure of Z of the formula (2) for improving the adhesion is more scum because the solubility of the resin is further lowered. Occurs and the resolution becomes very poor. However, when processed with an alkaline aqueous solution containing the anionic surfactant of the present invention, this scum does not occur at all.
Although the cause is not clear, it is considered that the anionic surfactant improves the affinity between the resin and the developer.

X of formula (2) which is the polyamide of the present invention
Is, for example,

[Chemical 5] However, the present invention is not limited to these.

Further, Y in the equation (2) is, for example,

[Chemical 6] However, the present invention is not limited to these.

Further, Z in the equation (2) is, for example,

[Chemical 7] However, the present invention is not limited to these.

Z in the formula (2) is used when adhesion is required to a substrate such as a silicon wafer,
With respect to the usage rate b, up to 40 mol% can be used. When it exceeds 40 mol%, the solubility of the resin is extremely lowered, scum occurs even when the pattern forming method of the present invention is used, and pattern processing cannot be performed. In addition, when using these X, Y, and Z, each may be one kind or a mixture of two or more kinds.

In the alkaline aqueous solution which is the developing solution of the present invention, in order to improve the wettability to scum existing at the interface between the substrate at the bottom of the pattern and the resin, and to dissolve and remove it,
It is important to contain the anionic surfactant represented by the formula (1).

As a technique for adding a surfactant to an alkaline aqueous solution, for example, Japanese Patent Publication No. 3-26380,
Japanese Patent Publication No. 4-55504, Japanese Patent Publication No. 5-40902, Japanese Patent Publication No. 6-3549, and Japanese Unexamined Patent Publication No. 1-7215.
No. 5 publication. However, even if the alkaline developer containing the surfactant as shown in these is applied to the positive photosensitive resin containing the polyamide of the present invention as the base resin, the effect on the good processability is small.

However, when the alkaline developing solution containing the anionic surfactant represented by the formula (1) of the present invention is used, scum at the bottom of the pattern is eliminated and, as a result, the resolution is improved. Examples of the anionic surfactant represented by the formula (1) include sodium dodecyldiphenyl ether disulfonate, ammonium dodecyl diphenyl ether disulfonate, dimethyl ammonium dodecyl diphenyl ether disulfonate, trimethyl ammonium dodecyl diphenyl ether disulfonate, and triethyl dodecyl diphenyl ether disulfonate. Ammonium salts, dodecyl diphenyl ether disulfonic acid tetramethyl ammonium salt, and the like,
It is not limited to these.

The content of the anionic surfactant in the alkaline aqueous solution which is the developer of the present invention is preferably 0.1 to 10% by weight based on the total alkaline aqueous solution. 0.
If it is less than 1% by weight, scum tends to be generated, while if it exceeds 10% by weight, the alkali concentration of the developer is lowered and the sensitivity is lowered.

Further, it is important that the alkaline aqueous solution which is the developing solution of the present invention contains a very small amount of chlorine.
As a technique relating to an alkaline aqueous solution to which an anionic surfactant is added, there is JP-A-4-204454, but an alkaline developing solution containing an anionic surfactant as shown in these documents is used as a base material based on the polyamide of the present invention. When it is applied to a positive photosensitive resin made into a resin, even if a scum-free pattern is obtained, the amount of resin film reduction is large during development and the required film thickness may not be obtained. This is because the anionic surfactant with such a structure is
This is because the structure has a very high affinity and penetrability with respect to the alkali-soluble resin such as the polyamide resin of the present invention, and thus has the ability to sufficiently dissolve the resin in the unexposed portion.

As a result of various studies, it was found that by adding an extremely small amount of chlorine to an alkaline aqueous solution containing an anionic surfactant, the unexposed area after development was maintained while maintaining good processability without scum. It was found that it has the effect of suppressing the amount of film loss. The chlorine concentration in the totally alkaline aqueous solution is preferably 2 to 200 ppm. When the chlorine concentration is less than 2 ppm, the amount of film loss after development becomes large and it becomes difficult to obtain a desired film thickness.
If it is more than 0 ppm, chlorine tends to remain even after development, so that the Al wiring in the semiconductor device is corroded and the reliability is lowered.

The alkaline aqueous solution of the present invention may contain compounds of calcium, strontium and barium in order to enhance the contrast of the resin pattern formed after development. The contrast enhancing effect of these metal compounds is caused by the metal compound strongly insolubilizing the coating film of the resin. Examples of these metal compounds, calcium oxide, calcium hydroxide, strontium oxide, strontium hydroxide, basic compounds such as barium oxide, barium hydroxide, calcium nitrate, calcium acetate, strontium nitrate, strontium acetate,
Examples thereof include inorganic or organic salts such as barium nitrate and barium acetate, but it goes without saying that the compounds are not limited to the above compounds. The content of these metal compounds varies depending on the kind of the metal used, but as the metal simple substance, 0.1 ppm or more and 1 pp of the whole developing solution.
m or less is desirable. If it is less than 0.1 ppm, the content of the metal compound is too small to obtain the effect of contrast enhancement. On the other hand, if it is more than 1 ppm, the solubility of the unexposed area as well as the exposed area is significantly reduced, the sensitivity is lowered, and the resolution is lowered.

The alkaline aqueous solution of the present invention dissolves and removes the alkali-soluble polymer, and it is essential that it is an aqueous solution in which an alkaline compound is dissolved. Examples of the alkaline compound include sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, inorganic alkalis such as aqueous ammonia, primary amines such as ethylamine and n-propylamine, diethylamine, di-n. -Secondary amines such as propylamine, tertiary amines such as triethylamine and methyldiethylamine, alcohol amines such as dimethylethanolamine and triethanolamine, quaternary ammonium such as tetramethylammonium hydroxide and tetraethylammonium hydroxide Examples thereof include salt.

The photosensitive resin composition used in the present invention contains a polyamide, a diazoquinone compound, and a solvent as main components, but a polyamic acid may be added if necessary. Since the polyamic acid has a carboxyl group, the solubility is increased and the development time can be shortened.

The diazoquinone used in the present invention is 1,2-
A compound having a benzoquinonediazide or 1,2-naphthoquinonediazide structure, which is disclosed in US Pat.
772,972, 2,797,213, 3,6
It is a substance known from No. 69,658.

For example,

[Chemical 8]

[Chemical 9] Etc. can be mentioned.

In the pattern forming method, first, the positive type photosensitive resin composition is applied to an appropriate support, for example, a silicon wafer, a ceramic, an aluminum substrate or the like. The coating method is spin coating using a spinner, spray coating using a spray coater, dipping, printing, roll coating, or the like. Next, the coating film is dried at a temperature of about 60 to 180 ° C. Examples of the drying method include an oven, an infrared furnace, and a heating plate, but the heating plate is preferable from the viewpoint of efficiency and easy temperature control. When drying with this heating plate, it is preferable to dry at 80 to 130 ° C. If the temperature is lower than 80 ° C, the drying is insufficient, which is not preferable.
On the other hand, if the temperature exceeds 130 ° C, drying becomes excessive, which is not preferable. More preferably, it is 2-4 at 100-120 degreeC.
Minutes.

Next, the desired pattern is irradiated with actinic radiation. The actinic rays include X-rays, electron rays, ultraviolet rays,
Visible light and the like can be used, but those having a wavelength of 200 to 500 nm are particularly preferable. In order to obtain a pattern with higher resolution, it is more preferable to use an i-line stepper using a wavelength of 365 nm or a g-line stepper using a wavelength of 436 nm.

The present invention will be specifically described below with reference to examples. Example 1 * Synthesis of Polyamide 0.8 mole of terephthalic acid and 0.2 mole of isophthalic acid
Dicarboxylic acid derivative obtained by reacting with 2 mol of -hydroxy-1,2,3-benzotriazole 360.4
g (0.9 mol) and hexafluoro-2,2-bis (3
-Amino-4-hydroxyphenyl) propane 366.
3 g (1.0 mol), thermometer, stirrer, raw material charging port,
The mixture was placed in a 4-neck separable flask equipped with a dry nitrogen gas introduction tube, and 3000 g of N-methyl-2-pyrrolidone was added and dissolved. Then, the reaction was carried out at 75 ° C. for 12 hours using an oil bath. After filtering the reaction mixture, the reaction mixture was poured into a solution of water / methanol = 3/1, the precipitate was collected by filtration, washed thoroughly with water, and then dried under vacuum to give the compound represented by the general formula (1), X Is the following formula X-1 and Y is the following formula Y-1
And Y-2, a polyamide (A-1) having a = 100 and b = 0 was obtained.

Preparation of positive photosensitive resin composition 100 g of synthesized polyamide (A-1) and 20 g of diazoquinone compound (Q-1) having the structure of the following formula were dissolved in 200 g of N-methyl-2-pyrrolidone. , 0.2μ
m through a Teflon filter to obtain a photosensitive resin composition.

* Characteristic Evaluation This positive photosensitive resin composition was applied onto a silicon wafer by using a spin coater and then dried at 120 ° C. for 4 minutes to obtain a coating film having a film thickness of about 5 μm. . A mask manufactured by Toppan Printing Co., Ltd. (Test Chart N
o. 1: a residual pattern and a blank pattern having a width of 0.88 to 50.0 μm are drawn), and light of 436 nm is irradiated at 50 to 500 mJ / cm ² by a g-line stepper. 1.35 parts by weight of tetramethylammonium hydroxide, 97.45 parts by weight of deionized water, and a surfactant (S-1) 1.2 having a structure represented by the following formula:
6 parts by weight using a developing solution containing 0 parts by weight and a chlorine concentration of 5 ppm
After the exposed portion was dissolved and removed by a paddle method for 0 seconds, it was rinsed with deionized water for 10 seconds. As a result, the exposure amount is 150m
From the portion irradiated with J / cm ² , it was confirmed that a scum-free pattern was formed with a resolution of 4 μm (sensitivity was 150 mJ / cm ² ). At this time, the film reduction rate (amount of film thickness reduction due to development / film thickness before development × 100 (%); the smaller this value is preferable) was 11.7%, which was a good value.

* Reliability evaluation of semiconductor device: Using a simulated element wafer having an Al circuit on the surface, the above positive type photosensitive resin is applied and exposed to a final thickness of 5 μm, and then patterned using the above developing solution. It was processed and finally baked. After that, divide by chip size to 16 pi
nDIP (Dual Inline Package)
Mounted on a lead frame for use with a conductive paste, and then molded with an epoxy resin for semiconductor encapsulation (EME-6300H manufactured by Sumitomo Bakelite Co., Ltd.) to obtain 16 pins.
Obtained DIP. These packages were treated under the conditions of 85 ° C / 85% humidity, immersed in a solder bath at 260 ° C for 10 seconds, and then subjected to a pressure cooker treatment of high temperature and high humidity (12
5 ° C., 2.3 atm, 100% RH) was applied to check the open failure of the Al circuit.

Example 2 In the synthesis of the polyamide in Example 1, diphenylether-4, instead of 0.8 mol of terephthalic acid and 0.2 mol of isophthalic acid was used.
Instead of 1.0 mol of 4'-dicarboxylic acid, the general formula (1)
, X is the following formula X-1, Y is the following formula Y-3, and a
= 100 and b = 0, polyamide (A-2) was synthesized, and the addition amount of each component was changed as shown in Table 1 to obtain a photosensitive resin composition in the same manner. Further, spin coating and pre-bake exposure were performed under the same conditions as in Example 1, and then 1.42 parts by weight of tetramethylammonium hydroxide and pure water 93.
Development was carried out in the same manner using a developing solution containing 78 parts by weight, 4.80 parts by weight of the surfactant (S-1), and a chlorine concentration of 23 ppm.

Example 3 In the synthesis of the polyamide in Example 1, hexafluoro-2,2'-bis (3
34-amino-4-hydroxyphenyl) propane
Reduced to 8.0 g (0.95 mol), instead 1,3-
12.4 g (0.05 mol) of bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane was added and represented by the general formula (1), where X is the following formula X-1, Y. Is the following formula Y-1 and Y-2, and Z is the following formula Z-1, and a = 9
5, a polyamide (A-3) composed of b = 5 was synthesized, and the addition amount of each component was changed as shown in Table 1 to obtain a photosensitive resin composition in the same manner. Further, spin coating and pre-bake exposure were performed under the same conditions as in Example 1, and then 1.30 parts by weight of tetramethylammonium hydroxide, 97.90 parts by weight of pure water, and surfactant (S-1) 0. Development was performed in the same manner using a developing solution having 80 parts by weight and a chlorine concentration of 8 ppm.

Example 4 Using the positive photosensitive resin composition of Example 1, and further under the same conditions as in Example 1,
After spin coating and pre-baking exposure, 1.35 parts by weight of tetramethylammonium hydroxide, pure water 9
7.65 parts by weight, a surfactant (S
-2) The development was carried out in the same manner using a developing solution containing 1.00 parts by weight and a chlorine concentration of 93 ppm.

Example 5 Using the positive photosensitive resin composition in Example 1, and further under the same conditions as in Example 1,
After performing spin coating and pre-baking exposure, 1.38 parts by weight of tetramethylammonium hydroxide, and pure water 9
7.37 parts by weight, a surfactant having the structure of the following formula (S
-1) The same development was performed using a developing solution having 1.25 parts by weight and a chlorine concentration of 147 ppm.

Example 6 Using the positive photosensitive resin composition in Example 1, and further under the same conditions as in Example 1,
After spin coating and pre-baking exposure, 1.35 parts by weight of tetramethylammonium hydroxide, pure water 9
7.45 parts by weight, a surfactant (S
-1) The same development was performed using a developing solution containing 1.20 parts by weight and a chlorine concentration of 3 ppm.

Example 7 In the production of the positive type photosensitive resin composition in Example 2, the diazoquinone compound (Q
(Q-2) was used instead of -1), the addition amount of each component was changed as shown in Table 1, and a photosensitive resin composition was similarly obtained. Further, spin coating and pre-baking were performed under the same conditions as in Example 1, and then 1.40 parts by weight of tetramethylammonium hydroxide, 97.30 parts by weight of pure water, and 1.30 of surfactant (S-1). Development was carried out in the same manner by using a developing solution containing 1 part by weight and a chlorine concentration of 5 ppm.

Comparative Example 1 In the preparation of the developer in Example 1, 1.35 parts by weight of tetramethylammonium hydroxide and 98.65 parts by weight of pure water are not used and the surfactant (S-1) is not included. The same evaluation as in Example 1 was carried out except that the above was changed to.

Comparative Example 2 In the preparation of the developing solution in Example 2, 1.42 parts by weight of tetramethylammonium hydroxide, 85.58 parts by weight of pure water, 13.00 parts by weight of surfactant (S-1). The same evaluation as in Example 2 was performed except that the developing solution was changed to a chlorine concentration of 64 ppm.

Comparative Example 3 In the preparation of the developing solution in Example 4, 1.35 parts by weight of tetramethylammonium hydroxide, 98.60 parts by weight of pure water, 0.05 part by weight of surfactant (S-2). The same evaluation as in Example 4 was performed except that the developing solution was changed to a chlorine concentration of 5 ppm.

Comparative Example 4 In the preparation of the developer in Example 1, 1.50 parts by weight of tetramethylammonium hydroxide, 97.30 parts by weight of pure water, and (S-1) instead of (S-1) were used. -3) Example 1 except that the developing solution was changed to 1.20 parts by weight and the chlorine concentration was 16 ppm.
The same evaluation as was done.

Comparative Example 5 In the preparation of the developing solution in Example 1, 1.35 parts by weight of tetramethylammonium hydroxide, 96.65 parts by weight of pure water, and (S-1) instead of (S-1) were used. -4) The same evaluation as in Example 1 was performed except that the developing solution was changed to 2.00 parts by weight and the chlorine concentration was 121 ppm.

Comparative Example 6 In the preparation of the developing solution in Example 1, 1.39 parts by weight of tetramethylammonium hydroxide, 97.41 parts by weight of pure water, 1.20 parts by weight of surfactant (S-1). The same evaluation as in Example 1 was performed except that the developing solution was changed to a chlorine concentration of 0.5 ppm.

Comparative Example 7 In the preparation of the developing solution in Example 1, 1.40 parts by weight of tetramethylammonium hydroxide, 97.30 parts by weight of pure water, 3.00 parts by weight of surfactant (S-1). The same evaluation as in Example 1 was performed except that the developing solution was changed to have a chlorine concentration of 813 ppm.

[0047]

[Chemical 10]

[0048]

[Chemical 11]

[0049]

[Chemical 12]

The results of Examples and Comparative Examples are shown in Table 1.

[Table 1]

[0051]

According to the present invention, when a positive photosensitive resin composition is developed with an alkaline aqueous solution containing an anionic surfactant and an extremely small amount of chlorine, not only the sensitivity and the film reduction rate are excellent but also the undeveloped residue (scum). Does not occur. Therefore, the positive photosensitive resin composition comprising polyamide and a quinonediazide compound can form a pattern with extremely high resolution.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-9-329898 (JP, A) JP-A-6-89031 (JP, A) JP-A-8-328245 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G03F ^7/ 00-7/42

Claims (4)

(57) [Claims] 1. A developer for a positive type photosensitive resin composition comprising an anionic surfactant and an alkaline aqueous solution containing chlorine, wherein the anionic surfactant is represented by the following formula (1) and the chlorine concentration is: There, Ri 2~200ppm der,該A
When the content of the nonionic surfactant is 0.1 to 10% by weight,
A developer for a positive photosensitive resin composition, which is characterized by being present. [Chemical 1] 2. The developer for a positive photosensitive resin composition according to claim 1, wherein the positive photosensitive resin composition comprises a polyamide and a diazoquinone compound. 3. A positive photosensitive resin composition is applied to a substrate or the like, prebaked and irradiated with light, and then an anionic surfactant represented by the following formula (1), the concentration of which is 2 to 200 ppm.
In a Ri Do an alkaline aqueous solution containing a chlorine, the anion
The content of the cationic surfactant is 0.1 to 10% by weight. The exposed portion is dissolved and removed with a developing solution to obtain a pattern, which is a positive photosensitive resin composition. Pattern formation method. [Chemical 2] 4. The method for forming a pattern of a positive photosensitive resin composition according to claim 3 , wherein the positive photosensitive resin composition comprises a polyamide and a diazoquinone compound.