KR20220028440A - Photosensitive polyimide and composition comprising the same - Google Patents

Abstract

The present invention relates to a photosensitive polyimide, and particularly, to a polyimide compound having a novel structure and showing excellent photosensitivity, while realizing excellent mechanical properties even with no heat treatment step at high temperature. The present invention also relates to a photosensitive polyimide composition using the polyimide compound. The polyimide-based compound according to the present invention has at least one amide bond to provide excellent mechanical properties, such as flexibility, and high heat resistance and adhesion. The photosensitive composition including the polyimide-based compound can realize a polyimide layer showing a high film retention ratio and excellent developability and mechanical properties with no need for a separate imidization step at high temperature by virtue of the polyimide-based compound.

Description

Photosensitive polyimide and composition comprising the same

The present invention relates to a photosensitive polyimide, and more particularly, to a low-temperature curing type negative photosensitive polyimide that can be used as a coating agent for semiconductor surface protection and an insulating film for wafer level packages, and a composition thereof.

Polyimide is a polymer having an imide bond and has great industrial importance because it has excellent thermal, chemical, and mechanical properties. In particular, it is used in various fields in the electrical, electronic and semiconductor industries due to its excellent mechanical and electrical properties. In particular, photosensitive polyimide is in the spotlight as a photosensitive resin for modular electrical and electronic components, such as a coating film or insulating material for semiconductor surface protection, and a chip size package (CSP) or wafer level package (WLP).

In general, polyimide has insufficient solubility, so a photosensitive polyimide composition is prepared in the polyamic acid state, which is its precursor state, and cured at a high temperature after a lithography process to obtain a stable polyimide. A photosensitive polyimide composition is coated on a substrate such as a wafer to form a thin film, and then UV is irradiated through a patterned photomask. In this case, the solubility of the UV-irradiated portion and the non-irradiated portion in the developer is different, so that a desired pattern can be obtained. In this case, the case where the solubility is increased by UV is called a positive type, and the case where the solubility is decreased is called a negative type.

As a representative technique of negative photosensitive polyimide, US Patent No. 3,957,512 discloses a polyamic acid in which photosensitive functional groups are linked in the form of an ester bond. And Japanese Patent No. 52-133152 mentions a photosensitive polyimide technology using naphthaquinonediazide as a dissolution inhibitor. In addition, Korean Patent Application Laid-Open No. 10-2014-0073277 describes a method for producing a negative photosensitive polyimide in which a photoreactive cinnamate group is introduced instead of such a dissolution inhibitor.

Such a conventional method for producing a photosensitive polyimide has a problem in that it requires a high curing temperature or excessive shrinkage occurs due to the desorption of the photosensitive reactor bonded in the form of an ester during the curing process. On the other hand, when using a polymer imidized in advance through chemical imidization reaction, mechanical properties such as tensile elongation are often insufficient, and it is difficult to add a photosensitive reactor during the compound manufacturing process, so it is economical in the manufacturing process such as going through a polymer re-precipitation process. There is an adverse problem.

US Patent No. 3,957,512 Korean Patent Publication No. 10-2014-0073277

The problem to be solved by the present invention is to provide a method for producing a polyimide-based compound that exhibits an excellent residual film rate during UV exposure and development process and has excellent mechanical properties.

In addition, another object to be solved by the present invention is to provide a negative photosensitive polyimide composition capable of implementing a polymer layer having excellent mechanical properties and excellent residual film rate at a low curing temperature.

In order to solve the above problems, the present invention includes a compound having a structure as shown in Formula 1 below.

In Formula [1], a is an integer from 1 to 100 and b is an integer from 5 to 100. where a:b = in the range of 1:1 to 1:100,

X is an aromatic, aliphatic, or alicyclic divalent radical having 4 to 20 carbon atoms derived from diamine, and includes at least one in the following structure,

Y is an aromatic or cycloaliphatic tetravalent radical having 4 to 20 carbon atoms derived from dianhydride, and includes at least one of the following structures.

Since the polyimide-based compound of the present invention has one or more amide bonds, mechanical properties such as flexibility may be excellent, and heat resistance and adhesion may be excellent.

The photosensitive composition containing the polyimide-based compound of the present invention includes a polyimide-based polymer layer having high film retention rate, excellent developability, and excellent mechanical properties without the need for a separate imidization process at high temperature by including the polyimide-based compound. can be implemented.

1 is a 1H NMR spectrum of the polyimide compound synthesized in Synthesis Example 1 of the present invention.

The polyimide-based polymer described in the present invention is a copolymer in a conventional sense as prepared using two or more monomers. For example, if (A)a-(B)b is indicated, it is a copolymer consisting of monomer A and monomer B, and a and b mean the ratio of the two monomers, and random copolymerization in which A and B are irregularly arranged in the polymer chain. It is not particularly limited whether the change is a block copolymer composed of A block and B block, or an alternating copolymer in which A and B are alternately arranged.

Hereinafter, the present disease will be described in more detail.

The polyimide of the present invention exhibits insolubility in a developer without a separate crosslinking agent by introducing a reactive group capable of causing a crosslinking reaction by photoreaction in the polymer chain as shown in [Scheme 1], and thus can be used as a negative photosensitive polyimide.

[Scheme 1]

The present invention relates to a negative photosensitive polyimide comprising a compound represented by [Formula 1], and the present invention will be described in more detail below.

[Formula 1]

Here, a is an integer from 1 to 100 and b is an integer from 10 to 100. where a:b = 1:1 to 1:100.

X is an aromatic, aliphatic, or alicyclic divalent radical having 4 to 20 carbon atoms derived from diamine, and may be used alone or in combination. A representative structure is as follows, and the present invention is not limited thereto.

Although the photosensitive polyimide organic solution of the present invention exhibits excellent developability, in order to impart solubility to an aqueous alkali solution, a structure having a COOH or OH group may be used alone or in combination as follows.

Here, Y is an aromatic or cycloaliphatic tetravalent radical having 4 to 20 carbon atoms derived from dianhydride, and a typical structure is as follows.

The present invention relates to a negative photosensitive polyimide, and in detail, may include a compound represented by the following [Formula 2].

Here, b is an integer of 10 to 100, Y is an aromatic or cycloaliphatic tetravalent radical having 4 to 20 carbon atoms derived from dianhydride, and the typical structure is as follows.

The photosensitive composition including the polyimide-based compound of the present invention can secure excellent developability with respect to an organic solvent in a post-exposure development process when a pattern is formed. As the organic solvent, an organic solvent used in the development process in the art may be selected without limitation. For example, the organic solvent is cyclopentanone (CPN), cyclohexanone (CHN), N-methyl-2-pyrrolidone (N-Methyl-2-pyrrolidone, NMP), propylene glycol mono methyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and the like.

In the photosensitive polyimide composition of the present invention, in order to increase developability in aqueous alkali solution, a structure including COOH or OH groups may be used together, and a compound represented by the following [Formula 3] may be included.

Here, m and n are integers from 1 to 100, respectively, but m+n is in a relationship of 10 to 100, and the ratio of m:n is in the range of 100:1 to 1:100, preferably 10:1 to 1:10. is in the range of

The m and n represent the degree of polymerization of each polymer, and when the degree of polymerization is 10 or less, coating properties or mechanical properties may be a problem. should have In addition, the ratio of m and n represents the ratio of the component (m) soluble in aqueous alkali solution and the component (n) where the curing reaction occurs by UV exposure. When m:n is 100:1 or more, the solubility is too high, It is difficult to obtain, and in the case of 1:100 or less, the solubility is too low and development is difficult, so it should be adjusted in an appropriate range. However, such content is not specifically claimed in the present invention as content that can be easily understood by anyone working in the same industry.

In [Formula 3], Y is an aromatic or cycloaliphatic tetravalent radical having 4 to 20 carbon atoms derived from dianhydride, and a typical structure is as follows.

When the present invention is described in more detail, the compound of [Formula 2] can be prepared using the diamine of [Formula 4] in the following reaction

By using the compound of the present invention, it is possible to provide a photosensitive composition capable of implementing a polymer layer having excellent mechanical properties and excellent heat resistance and adhesion at a low curing temperature. Hereinafter, the negative photosensitive polyimide composition of the present invention will be described.

The photosensitive composition of the present invention may further include several additives in addition to the above compound. The additive includes a photoinitiator, an imidization catalyst, a photo base generator, a thermal base generator, a polyfunctional monomer, a base catalyst, a dehydrating agent, a surfactant, a coupling agent, a reaction catalyst, a flame retardant, It may include at least one or several of an adhesion enhancer, inorganic particles, antioxidants, plasticizers, ultraviolet absorbers, pigments, and antistatic agents. Specifically, the photosensitive composition comprises at least an imidization catalyst, a photoinitiator, a photobase generator, a thermal base generator, a base catalyst, and a photosensitive composition.

It may contain a polyfunctional monomer that induces an additional crosslinking reaction of the included compounds. However, the type of additive included in the photosensitive composition is not limited.

The polyfunctional monomer included in the photosensitive composition is a monomer containing two or more functional groups, and one of the functional groups of the polyfunctional monomer may react with the double bond included in [Formula 1] to be bonded. Another hyperfunctional group of the polyfunctional monomer bonded to the double bond of the polyimide compound may react with the double bond of the other polyimide compound to form a cross-linking. In addition, cross-linking may be formed between the respective polyfunctional monomers bonded to the double bonds of the plurality of polyimide compounds. In this case, cross-linking may be induced through a photoinitiator.

Through this, the photosensitive composition can easily provide a patterned film having excellent adhesion to a substrate such as a wafer, glass, and a printed circuit board (PCB).

The polyfunctional monomer is dipentaerythritol hexaacrylate [dipentaerythritol hexaacrylate (DPHA)], tripropylene glycol diacrylate [(tripropylene glycol diacrylate (TPGDA)], trimethylolpropane triacrylate [trimethylolpropane triacrylate (TMPTA) )], pentaerythritol tetraacrylate (PETA), dipentaerythritol hexaacrylate [dipentaerythritolhexaacrylate (DPEHA)], and GPO-303 products. However, the type of the polyfunctional monomer is not limited.

The imidization catalyst may convert polyamic acid, which may be present in the photosensitive composition, into a polyimide-based compound. The imidation catalyst is pyridine, isoquinoline, β-quinoline (β, N,N-dimethylformamide, N,N dimethylacetamide, N-methylpyrrolidone, N-vinylpyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, m-cresol, γ-butyrolactone, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol , may include at least one of ethyl carbitol acetate, butyl carbitol acetate, ethylene glycol, propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate, butyl lactate, cyclohexanone, and cyclopentanone.

The photosensitive composition obtained by the present invention can be applied in various forms in an area requiring a fine pattern. For example, it can be applied to a multilayer printed wiring board including a film, a protective film or an insulating film, a flexible circuit board, a laminate for semiconductors, a photosensitive organic insulating material for OLED devices, and the like.

According to an embodiment of the present invention, when a photosensitive composition containing a polyimide-based compound including a repeating unit represented by the [Formula I] is coated and exposed to light, the photosensitive composition in the exposed area is cured, and the photosensitivity of the non-exposed area is The composition can be removed by a developer. In this case, since the photosensitive composition includes the polyimide-based compound, photocuring occurs easily with high sensitivity even when exposed to a small amount of light, and the exposed film may have excellent mechanical properties.

Hereinafter, examples will be given to describe the present invention in detail. However, the embodiments according to the present invention are provided so that average practitioners in the relevant field can more easily understand the contents of the present invention, and do not limit the scope of the present invention.

Synthesis Example 1

Synthesis of 3,3'-(1,4-phenylene)bis(N-(4-aminophenyl)acrylamide) (compound represented by the present invention [Formula 4])

In a nitrogen atmosphere, in a mixed solvent of N-methylpyrrolidone (NMP)/pyridine (v/v=4/1), 1,4-phenylenediacrylic acid (12 g, 55 mmol) and 5 equivalents of p- After dissolving phenylenediamine (30 g, 275.2 mmol), triphenyl phosphate (TPP) (34.1 g, 110.1 mmol) was added thereto, stirred at room temperature for 2 hours, and fully aged, then slowly raised to 150 ^o C for 8 hours reacted while After cooling to room temperature, precipitation in excess methanol, washing 2-3 times, and recrystallization from DMF/water (DMF/H ₂ O), purified compound 1,4-phenylenebis (N-( 4-aminophenyl) acrylamide [3,3'-(1,4-phenylene)bis(N-(4-aminophenyl)acrylamide)](PBAA) was obtained.The yield of synthesized PBAA was 82% (18.0 g) ( ¹ H NMR (300 MHz, DMSO-d6): δ4.9(4H, s), δ6.5(4H, d), δ6.8(2H, d), δ7.3(4H, d), δ7.5(2H, d), δ7.7(4H, s), δ9.8(2H, s))

Example 1

Preparation of polyimide-based compounds

In a 3-neck flask, put 51.52 g of N-methyl-2-pyrrolidone (N-Methyl 2-pyrrolidone, NMP) and 1,4-phenylenebis (N- (4-aminophenyl) acrylamide [3,3' -(1,4-phenylene)bis(N-(4-aminophenyl)acrylamide)](PBAA) (3.785g , 9.95mmol) was added and dissolved under a nitrogen stream Then Pyromellitic anhydride (PMDA) ) (2.17 g , 9.95 mmol) was slowly added and stirred at room temperature for 24 hours, 20.61 g of toluene and 0.79 g (10 mmol) of pyridine were added to the viscous polymer solution, refluxed at 160 ° C. for 16 hours, and then refluxed for 2 hours. Toluene and pyridine remaining during the process were removed to obtain a polyimide-based compound having the following structure.

The b calculated based on the weight average molecular weight and the number average molecular weight measured by GPC was 30 to 31.

Evaluation of the polyimide photosensitive composition

Each of the negative photosensitive polyimide compositions prepared in Example was spin-coated and coated on a silicon wafer, followed by prebaking (PRB) at 120° C. for 2 minutes to obtain a polyimide film having an average thickness of 15 μm. The resulting film was irradiated with UV of 500 mJ using an ultra-high pressure mercury lamp, and developed for 2 minutes at 23° C. using a cyclopentanone (CPN) or 2.38% tetramethylammonium hydroxide (TMAH) solution. The finally obtained thin film was placed in a convection oven and heat-treated at 230° C. for 60 minutes under a nitrogen stream.

For the obtained film, the thickness of the patterned film was measured using an alpha-step surface profiler (ET-3000, Kosaka Laboratory), and the remaining film rate was calculated using the following equation.

Remaining film ratio (%) = (film thickness after development / film thickness after prebaking) x 100

The obtained film was measured for tensile strength and elongation in accordance with ASTM D882 using an Instron universal testing machine (UTM).

Hereinafter, a photosensitive polyimide composition was prepared in the same manner, and the evaluation results thereof are shown in Table 1 together with comparative examples.

Example 2

1,4-phenylenebis (N- (4-aminophenyl) acrylamide [3,3'- (1,4-phenylene) bis (N- (4-aminophenyl) acrylamide)] in the same manner as in Example 1 (PBAA) (3.785 g , 9.95 mmol) and cyclohexane-1,2,3,4-tetracarboxylic dianhydride [cyclohexane-1,2,3,4-tetracarboxylic dianhydride] (CHDA) (2.230 g , 9.95 mmol) are reacted to form a polyimide having the following structure a compound was obtained

The b calculated based on the weight average molecular weight and the number average molecular weight measured by GPC was 19 to 20.

Example 3

Put 51.52 g of N-methyl-2-pyrrolidone (NMP) in a 3-neck flask and 1,4-phenylenebis (N- (4-aminophenyl) acrylamide (PBAA) (1.894) g , 4.98 mmol) and 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane (Bis-AP-AF) (1.824 g 4.98 mmol) and dissolved under a nitrogen stream.Then, Pyromellitic anhydride (PMDA) (2.172g, 9.96mmol) was slowly added and stirred at room temperature for 24 hours.Toluene 20.61 in a viscous polymer solution g and 0.79 g (10 mmol) of pyridine, refluxed at 160° C. for 16 hours, and toluene and pyridine remaining for 2 hours were removed to obtain a polyimide-based compound having the following structure.

Here, m:n is 1:1, and m+n = 16~17 calculated based on the weight average molecular weight and the number average molecular weight measured by GPC.

Example 4

In the same manner as in Example 3, 1,4-phenylenebis(N-(4-aminophenyl)acrylamide (PBAA) (1.894g, 4.98mmol) and 2-bis(3-amino-4-hydroxyphenyl) Hexafluoropropane (2-Bis(3-amino-4-hydroxyphenyl)hexafluoropropane) (Bis-AP-AF) (1.824 g 4.98 mmol) and cyclohexanetetracarboxylic acid dianhydride (CHDA) (2.230 g , 9.95 mmol) was reacted to obtain a polyimide-based compound having the following structure.

Here, m:n is 1:1, and m+n = 12~13 calculated based on the weight average molecular weight and the number average molecular weight measured by GPC.

Comparative Example 1

Put 51.52 g of N-methyl-2-pyrrolidone (NMP) in a 3-neck flask and m-phenylene diamine (m-PDA) (1.075 g , 9.95 mmol) was added and dissolved under a nitrogen stream. Then, cyclohexane tetracarboxylic acid dianhydride (CHDA) (2.230g, 9.95mmol) was slowly added and stirred at room temperature for 24 hours. To a viscous polymer solution, 20.61 g of toluene and 0.79 g (10 mmol) of pyridine were added, refluxed at 160 ° C. for 16 hours, and the remaining toluene and pyridine were removed for 2 hours to obtain a polyimide-based compound having the following structure.

The b calculated based on the weight average molecular weight and the number average molecular weight measured by GPC was 80 to 81.

Comparative Example 2

By the method of Example 2, p-phenylenediamine (PDA) (0.538 g, 4.98 mmol) and 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane (2-Bis (3-amino-4) -hydroxyphenyl)hexafluoropropane)(Bis-AP-AF) (1.824g 4.98mmol) and cyclohexanetetracarboxylic dianhydride (CHDA) (2.230g, 9.95mmol) were reacted to obtain a polyimide-based compound having the following structure.

Here, m:n is 1:1, and m+n = 12~13 calculated based on the weight average molecular weight and the number average molecular weight measured by GPC.

photosensitivity mechanical properties developer Remaining film rate (%) Tensile strength (MPa) Tensile Elongation (%) Example 1 CPN 83 210 36 Example 2 CPN 78 140 17 Example 3 TMAH 79 175 23 Example 4 TMAH 72 120 19 Comparative Example 1 CPN 40 96 9 Comparative Example 2 TMAH Dissolution 85 7

In Table 1, CPN means cyclopentanone and TMAH means 2.38% of Tetramethylammoniumhydroxide as described in the text of the developer. Since the composition of Comparative Example has a high degree of dissolution by the developer, mechanical properties were obtained by measuring the film that did not go through the developing process after exposure.

From the above results, it was confirmed that the photosensitivity and mechanical properties of the polyimide-based compound according to the present invention were simultaneously improved by having a double bond and an amide group in the molecular structure.

As a specific part of the present invention has been described in detail above, for those of ordinary skill in the art, it is clear that this specific description is only a preferred embodiment, and the scope of the present invention is not limited thereby. will be. Accordingly, it is intended that the substantial scope of the present invention be defined by the appended claims and their equivalents.

Claims (6)

A polyimide compound comprising the following [Formula 1]:
[Formula 1]

In [Formula 1], a is an integer from 1 to 100 and b is an integer from 5 to 100. where a:b = in the range of 1:1 to 1:100,
X is an aromatic, aliphatic, or alicyclic divalent radical having 4 to 20 carbon atoms derived from diamine, and includes at least one in the following structure,

Y is an aromatic or cycloaliphatic tetravalent radical having 4 to 20 carbon atoms derived from dianhydride, and includes at least one of the following structures.

The polyimide compound according to claim 1, wherein the [Formula 1] has the following [Formula 2] structure:
[Formula 2]

In the above formula, b is an integer from 1 to 100, Y is an aromatic or cycloaliphatic tetravalent radical having 4 to 20 carbon atoms derived from dianhydride, and includes at least one of the following structures.

The polyimide compound according to claim 1, wherein the [Formula 1] has a structure of the following [Formula 3]:
[Formula 3]

In [Formula 3], m and n are integers of 1 to 100, respectively, but m+n is in a relationship of 10 to 100, and the ratio of m:n is in the range of 100:1 to 1:100. The photosensitive composition comprising the polyimide-based compound according to any one of claims 1 to 3. 5. The method of claim 4, wherein a crosslinking monomer comprising at least one of an acrylate group-containing monomer, a methacrylate group-containing monomer, a vinyl group-containing monomer, a vinyl oxy group-containing monomer, an alkynyl group-containing monomer, and an epoxy group-containing monomer is added. A photosensitive composition comprising a. 5. The photosensitive composition of claim 4, further comprising an additive comprising at least an imidization catalyst.

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