JP2000007783A - Polyimide precursor resin composition and preparation thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide polyimide precursor resin compositions useful as interlaminar insulating layers and surface protective films of electronic parts such as semiconductor integrated circuits and high density packaging substrates and a method for preparing the same. SOLUTION: This polymide precursor resin composition comprises a polyimide precursor resin having a repeating unit represented by the general formula (I) (wherein R1 is a tetravalent aromatic group; R2 and R3 are each independently H or a 1-4C alkyl; R4 is an aromatic group; R5 is carboxy and/or phenolic hydroxy; and n is an integer of not less than 1) and the method for preparing the polyimide precursor resin composition comprises adding a >=4C alcohol to an aromatic tetrabasic acid dianhydride in a solvent and heating the resulting mixture solution to converting part of or the entire of the aromatic tetrabasic acid dianhydride into the diester of the tetrabasic acid and subsequently reacting the resulting diester with an aromatic diamine compound having a carboxy group and/or a phenolic hydroxy group to produce the polyimide precursor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semiconductor integrated circuit,
The present invention relates to a polyimide precursor resin composition useful as an interlayer insulating film and a surface protective film for electronic components such as a high-density mounting board, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, to manufacture a multilayer wiring structure in a semiconductor integrated circuit or the like, a lower wiring layer 2 is formed on a semiconductor substrate 1 as shown in FIG. An interlayer insulating film 3 made of SiO ₂ , SiN or the like is formed thereon by a vapor phase growth method such as vacuum deposition or CVD (chemical vapor deposition), and a via hole is opened in the interlayer insulating film 3. Is used. However, in the method of forming the interlayer insulating film by the vapor phase growth method, the step of the lower wiring
Remains after forming, and when the upper wiring layer 4 is formed,
There is a problem that the wiring layer becomes extremely thin at the step portion and the wiring is liable to be cut. To improve this,
For example, as shown in FIG. 1 (a cross-sectional view of a semiconductor device),
A method of using polyamic acid as the interlayer insulating film 5 to form an interlayer insulating film in which the influence of the step of the lower wiring layer 2 is alleviated has been proposed, and is now widely used (Japanese Patent Publication No. Sho 51-4).
No. 4871, etc.).

However, the degree of integration in electronic components such as semiconductor integrated circuits has been remarkably improved, and the wiring structure has been increasingly multi-layered, and the need for flattening wiring steps has been further increasing. On the other hand, in the case of a polyamic acid obtained from the aromatic diamine and the aromatic tetrabasic dianhydride, the solubility of the polyamic acid in the solvent is extremely low, and the concentration of the solution cannot be increased. The flatness of the steps is not sufficient, and it is difficult to manufacture a multilayer wiring structure having two or more layers. Also, with respect to a very fine groove pattern, the embedding property of the polyimide film is insufficient, and there is a problem that voids are generated in the film in the groove portion.

On the other hand, as the concentration of a polyamic acid solution applied on a substrate having an insulating layer on which a pattern is formed is increased, the flattening rate of a wiring step and the embedding of a groove pattern are increased. It has been reported that the formation of a low molecular weight ester oligomer is effective for improving the water-soluble property and increasing the concentration of the polyamic acid solution (Japanese Patent Application Laid-Open No. Sho.
No. 3-14452).

On the other hand, it is necessary to form through holes at predetermined positions after forming the interlayer insulating film and the surface protective film of the semiconductor. In the case of a polyimide-based film, a negative or positive resist is generally used as a mask to hydrate the film. A method of forming a hole by a wet etching process using hydrazine or tetramethylammonium hydroxide is used. However, as a result of evaluating the applicability of the polyamic acid solution obtained by the above-mentioned conventionally known low molecular weight ester oligomerization to the wet etching process, there is a problem that a crack is generated in a through-hole portion and the like. It became clear that we could not.

[0006]

The invention described in claim 1 can be applied to a wet etching process using a resist as a mask, and has good flatness of a step and good embedding of a fine groove-like pattern. It is intended to provide a polyimide precursor resin composition having excellent properties. The invention according to claim 2 is a polyimide precursor resin composition which is applicable to a wet etching process using a resist as a mask, has good step flatness and fine groove pattern embedding property, and has excellent workability. An object of the present invention is to provide a method for producing a polyimide precursor resin composition that can be produced and that can reduce the content of chlorine atoms and the like that are problematic in semiconductor devices and the like.

[0007]

The present invention provides a compound represented by the general formula (I):

Embedded image (Wherein, R ¹ represents a tetravalent aromatic group, R ² and R ³ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ⁴ represents an aromatic group, R ⁵ represents a carboxyl group and / or a phenolic hydroxyl group, and n is an integer of 1 or more.) The present invention relates to a polyimide precursor resin composition containing a polyimide precursor resin having a repeating unit represented by the following formula:

[0008] The present invention also provides an aromatic tetrabasic dianhydride in a solvent, to which an alcohol and / or an alcohol derivative having 4 or less carbon atoms is added and heated to form a tetrabasic dianhydride. A polyimide precursor is produced by reacting a part or all of a diester of a tetrabasic acid with an aromatic diamine compound having a carboxyl group and / or a phenolic hydroxyl group and, if necessary, other diamine compounds. And a method for producing a polyimide precursor resin composition.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyimide precursor resin in the polyimide precursor resin composition of the present invention has a repeating unit represented by the above general formula (I). By repeating the general formula (I), R ¹ , R ² , R ³ , R ⁴ and R ^{5 which} appear repeatedly may be the same or different. This repeating unit accounts for 10 mol% to 1 mol based on the total number of repeating units composed of one tetracarboxylic acid residue and one diamine residue of the polyimide precursor.
00 mol% is preferred. In addition, R ^{2 of the} repeating unit
And R ³ , an alkyl group having 1 to 4 carbon atoms has 5
It is preferable that the content be from mol% to 100 mol%.

R ¹ is a tetravalent aromatic group, which means a tetravalent organic group containing an aromatic ring (benzene ring, naphthalene ring, etc.). It is preferable that all four binding sites are present on the aromatic ring. These binding sites are divided into two sets of two binding sites, and the two binding sites are preferably located at the ortho or peri position on the aromatic ring. The above two sets may be present on the same aromatic ring, or may be present on separate aromatic rings linked via various bonds. As such an aromatic group, a residue of an aromatic tetrabasic acid or a derivative thereof capable of forming a polyimide resin by reacting with a diamine is preferable, and specifically, an aromatic tetrabasic acid dianhydride described later. Residues are more preferred. R ⁴ is an aromatic group;
This means an organic group containing an aromatic ring (benzene ring, naphthalene ring, etc.). The binding site is preferably present directly on the aromatic ring, in which case it may be present on the same aromatic ring or on a different aromatic ring.

The above polyimide precursor resin is heated by adding an alcohol and / or an alcohol derivative having 4 or less carbon atoms to an aromatic tetrabasic dianhydride in the presence of a solvent, It is obtained by reacting an aromatic diamine compound having a carboxyl group and / or a phenolic hydroxyl group and, if necessary, other diamine compounds after converting a part or all of the acid dianhydride into a diester. According to this method, the polymerization can be carried out by heat without using a catalyst such as thionyl chloride.
For example, the content of chlorine atoms or the like, which is a problem in a semiconductor device or the like, can be reduced, and an electronic component with excellent reliability can be provided.

In the present invention, the solvent used in the esterification of the aromatic tetrabasic dianhydride is N-methyl-2-
Pyrrolidone, N, N-dimethylacetamide, N, N-
Amide solvents such as dimethylformamide and dimethyl sulfoxide, and ether glycol solvents such as butyl cellosolve are preferred. When reacting an aromatic diamine compound having a carboxyl group and / or a phenolic hydroxyl group, the solvent used for the esterification, a hydrocarbon solvent such as xylene or toluene, or an ethyl solvent may be used, if necessary. Acetate solvents such as cellosolve acetate and butyl cellosolve acetate may be used.

The aromatic tetrabasic dianhydride used in the present invention includes, for example, pyromellitic dianhydride,
3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenylethertetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic Acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,3,5,6-pyridinetetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic dianhydride Anhydride, 4,4'-sulfonyldiphthalic dianhydride, 1-trifluoromethyl 2,3
There are 5,6-benzenetetracarboxylic dianhydride and substituted products thereof, and one or more of these are used.

Further, as the alcohol and alcohol derivative for esterifying the aromatic tetrabasic dianhydride of the present invention, those having 4 or less carbon atoms are used. If the number of carbon atoms is 5 or more, the ester portion does not detach during thermal curing, dehydration ring closure does not completely proceed, and a polyimide resin film having good characteristics cannot be obtained. Preferably, methanol, ethanol
One, two or more of them such as toluene, propanol and butanol are used. At this time, the amount of the alcohol and / or alcohol derivative to be used is preferably 0.1 mol or more per 1 mol of the tetrabasic dianhydride. If it is less than 0.1 mol, it tends to be difficult to lower the viscosity when the concentration is increased. The upper limit is not particularly limited, but is generally 2 mol or less.

The aromatic diamine compound having a carboxyl group and / or a phenolic hydroxyl group used in the present invention includes 2,5-diaminobenzoic acid, 3,4-diaminobenzoic acid, and 3,5-diaminobenzoic acid. , 2,5-
Diaminoterephthalic acid, bis (4-amino-3-carboxyphenyl) methylene, 4,4'-diamino-3,
3'-dicarboxybiphenyl, 4,4'-diamino-
5,5'-dicarboxy-2,2'-dimethylbiphenyl, 1,3-diamino-4-hydroxybenzene,
3-diamino-5-hydroxybenzene, 3,3'-diamino-4,4'-dihydroxybiphenyl, 4,4 '
-Diamino-3,3'-dihydroxybiphenyl, bis (3-amino-4-hydroxyphenyl) sulfone, bis (4-amino-3-hydroxyphenyl) sulfone,
Bis (3-amino-4-hydroxyphenyl) hexafluoropropane, bis (4-amino-3-hydroxyphenyl) hexafluoropropane, bis (4-amino-
3-hydroxyphenyl) methane and the like, which may be used alone or in combination of two or more. In these aromatic diamine compounds, the number of carboxyl groups and / or phenolic hydroxyl groups is not particularly limited as long as there is at least one per compound, but is preferably 1 to 5.

If necessary, other diamine compounds such as metaphenylenediamine, 3,4-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfide, para Phenylenediamine, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 4,4 '
-Diaminodiphenyl sulfide, 3,3 ', 5,5'
-Tetramethyl-4,4'-diaminodiphenylmethane, 2,2'-bis (4-aminophenyl) propane,
Aromatic diamines such as 4,4'-methylenedianiline and 4,4'-diaminodiphenylether-3-carbonamide, and 1,3-bis (3-aminopropyl) -1,1,1
One or a combination of two or more siloxane-based diamines such as 3,3-tetramethyldisiloxane can be used. The amount of these other diamine compounds to be used is preferably 90 mol% or less based on the total number of moles of the diamine compounds.

The reaction temperature of the esterification reaction in the present invention varies depending on the solvent used, but is preferably in the range of 60 to 150 ° C., from the viewpoint of the uniformity of the viscosity of the obtained resin composition and the hue of the resin composition. ~ 150 ° C is more preferred. After the esterification, excess alcohol or alcohol derivative can be removed to adjust the concentration, but in this case, the temperature is preferably set to a temperature equal to or higher than the boiling point of the alcohol or alcohol derivative.

In the present invention, in the reaction between the esterified aromatic tetrabasic dianhydride and the diamine compound, in order to optimize the heat resistance of the film obtained by curing the finally obtained resin composition, The total amount of the above-mentioned diamine compound is 0.8 to 1 per 1 mol of the aromatic tetrabasic dianhydride.
Preferably it is 2 moles. If the reaction temperature at this time is too high, the resulting polyimide precursor resin is imidized, the solubility is reduced, and precipitation occurs.

The polyimide precursor resin obtained as described above is generally used as a composition dissolved in a solvent. As the solvent, those listed in the description of the production of the polyimide precursor resin can be used. The concentration of the resin in the polyimide precursor resin composition is not particularly limited, but is preferably 30 to 70% by weight, and 40 to 70% by weight.
More preferably, it is 60% by weight. In addition, it is also possible to add an adhesion aid such as aminosilane or epoxysilane to the composition for the purpose of increasing the adhesion to the substrate surface.

The composition is applied on a silicon substrate or a ceramic substrate having a step on the surface by using a spin coating machine, a printing machine, a sprayer or the like, and is preferably dried at a temperature of 80 ° C. to 200 ° C. After that, it is possible to apply a positive or negative resist according to a normal photolithography process, expose the resist, and simultaneously wet-etch the dry film of the polyimide precursor resin and the resist with an alkaline developer to form a pattern. . Next, after removing the resist layer,
Preferably, the resin is cured at a temperature of 200 ° C. to 400 ° C. to be dehydrated and ring-closed to form a polyimide resin film. Thereby, a step can be covered and flattened at a specific portion of the substrate surface. In the etching step, a dry method using oxygen plasma or the like can be used in addition to a wet method using an alkali developing solution or a hydrazine-based etchant.

The polyimide film obtained by using the composition of the present invention is used as an interlayer insulating film or a surface protective film for electronic parts. Examples of the electronic component include a semiconductor device having a multilayer wiring structure, a ceramic high-density mounting board, and a ceramic hybrid board. After that, in the case of a semiconductor device, the semiconductor device is usually formed through a wire bonding step and a sealing step using a sealing material.

[0022]

The present invention will be described below with reference to examples and comparative examples. Example 1 A 0.2-liter flask equipped with a stirrer, a thermometer, a nitrogen inlet tube and a Dimroth condenser was installed, and dry nitrogen was flowed for one hour. Among them, N-methyl-2-pyrrolidone
0 g and 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride 32.21 g were charged into a flask,
After heating to 80 ° C., 6.9 g of ethanol was added, and the mixture was further reacted at 90 ° C. for 2 hours to esterify a part (75 mol%) of benzophenonetetracarboxylic dianhydride.
Next, 6.89 g of 3,5-diaminobenzoic acid was added to this solution,
9.01 g of 4,4'-diaminodiphenyl ether and 1,3-bis (3-aminopropyl) -1,1,3,3
2.49 g of 3, -tetramethyldisiloxane was charged,
The reaction was carried out at 25 ° C. for 5 hours and at 40 ° C. for 1 hour. Resin concentration of the obtained polyimide precursor resin composition is 40% by weight.
Showed a viscosity of 8 ps at 25 ° C.

Next, a linear projection pattern having a thickness of 1 μm and a width of 1 μm and a linear groove pattern having a depth of 1 μm and a width of 1 μm are formed on a silicon substrate formed by a usual photolithography and dry etching process. The above polyimide precursor resin composition was applied using a spinner coating machine. Thereafter, using a hot plate, 90 ° C./60 seconds, and then 150 ° C./60 seconds.
After drying for 60 seconds, convection oven at 200 ° C
/ 1 hour, cured at 350 ° C for 1 hour to obtain a polyimide film having a thickness of 2 µm. The flattening rate of the initial steps due to the obtained polyimide film was calculated from the values of a and b shown in FIG.

(Equation 1) Was about 90%.

When the silicon substrate was cut at the groove pattern and the cross-sectional shape was observed with a scanning electron microscope, it was found that all the grooves were sufficiently filled with the polyimide resin.

In order to further examine the processability, the polyimide precursor composition of the present invention was spin-coated on a silicon substrate at the same film thickness as described above, and was heated at 90 ° C./90° C. using a hot plate.
After drying at 150 ° C./60 seconds for 60 seconds, a positive resist (trade name: OFPR-5000, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is spin-coated, dried at 110 ° C./60 seconds, and then using a g-line stepper. It was exposed (exposure amount: 300 mJ / cm ² ). Then, 2.38% by weight of tetramethylammonium hydroxide
When the resist and the dried polyimide resin film were simultaneously etched by a paddle method using an aqueous solution, a good pattern was obtained in an etching time of 60 seconds. Also, after stripping the resist by a spray method using n-butyl acetate,
No abnormality was found in the patterned polyimide resin dry film.

Comparative Example 1 N-methyl-2-pyrrolidone 6 was prepared in the same manner as in Example 1.
5.96 g and 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride 32.21 g were charged into a flask, heated to 80 ° C, 6.9 g of ethanol was added, and the mixture was further heated at 90 ° C. The reaction was carried out for 2 hours to convert a part of benzophenonetetracarboxylic dianhydride into a diester. Next, 4.86 g of metaphenylenediamine, 4,
9.01 g of 4'-diaminodiphenyl ether and 1,
3-bis (3-aminopropyl) -1,1,3,3,-
2.49 g of tetramethyldisiloxane was charged, and the temperature was 25 ° C.
For 5 hours and at 40 ° C. for 1 hour. When the resin concentration of the obtained polyimide precursor resin composition is 40% by weight, 25%
It showed a viscosity of 13 ps at ° C.

In the same manner as in Example 1, the flattening rate of the step, the embedding property of the groove pattern, the wet workability, and the film state after the resist was stripped were observed. As a result, the flattening rate was 90% and the embedding property was good, but the dried polyimide resin film was hardly dissolved in the etching solution, and processing was impossible. Processing can be performed by setting the drying temperature of the polyimide precursor composition to 140 ° C. or lower. However, after etching, an etching residue remains in the opening of the polyimide film, and cracks occur in the polyimide film after the resist is peeled off.

[0028]

The polyimide precursor resin composition according to the first aspect is applicable to a wet etching process, has good step flatness and good embedding of a fine groove pattern, and has excellent workability. According to the production method of the second aspect, a polyimide-based precursor resin composition which is applicable to a wet etching process, has good step flatness and fine groove pattern embedding property, and is excellent in workability is produced. can do.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a multi-layer wiring structure having an interlayer insulating film made of a polyimide resin and alleviating the influence of a step in a lower wiring layer.

FIG. 2 is a cross-sectional view showing an example of a multilayer wiring structure in which an SiO ₂ film formed by a vapor deposition method is used as an interlayer insulating film.

FIG. 3 is an explanatory diagram illustrating a method for evaluating a flattening rate according to the first embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 semiconductor substrate 2 lower wiring layer 3 interlayer insulating film 4 upper wiring layer 5 interlayer insulating film

Continued on the front page F term (reference) 4J002 CM041 EA056 ED026 EH156 EP016 EU026 EV206 FD206 GP03 GQ01 GQ05 4J043 PA02 PA04 PA19 PC065 PC145 PC165 PC205 QB15 QB25 RA06 SA06 SB01 SB03 TA12 TA32 TB01 UA121 UA1 UA1 UA1 UA1 UB152 UB281 UB301 UB302 UB351 UB401 UB402 VA011 VA021 VA041 VA051 VA061 VA081 ZA46 ZB02 ZB11 ZB22 ZB50 5F058 AA06 AC02 AH02 AH03

Claims (2)

[Claims] 1. A compound of the general formula (I) (Wherein, R ¹ represents a tetravalent aromatic group, R ² and R ³ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ⁴ represents an aromatic group, R ⁵ represents a carboxyl group and / or a phenolic hydroxyl group, and n is an integer of 1 or more.) A polyimide precursor resin composition containing a polyimide precursor resin having a repeating unit represented by the following formula: 2. An aromatic tetrabasic acid dianhydride in a solvent,
An alcohol having 4 or less carbon atoms and / or an alcohol derivative is added and heated to convert a part or all of the tetrabasic dianhydride to a tetrabasic acid diester, followed by a carboxyl group and / or a phenolic hydroxyl group. A method for producing a polyimide precursor resin composition, comprising reacting an aromatic diamine compound having the formula (I) with another diamine compound as required to produce a polyimide precursor.