JP5396794B2 - Photosensitive resin composition and pattern forming method - Google Patents

Description

  The present invention can be suitably used as a material of a product or member formed through a patterning process using electromagnetic waves (for example, an electronic component, an optical product, a molding material of an optical component, a layer forming material, an adhesive, or the like). The present invention relates to a photosensitive resin composition using a polyimide precursor, an article produced using the resin composition, and a pattern forming method using the resin composition.

  Polyimide is a polymer synthesized from diamine and acid dianhydride. By reacting diamine and acid dianhydride in a solution, it becomes polyamic acid (polyamic acid) which is a precursor of polyimide, and then becomes a polyimide through a dehydration ring closure reaction. In general, since polyimide has poor solubility in a solvent and is difficult to process, it is often made into a polyimide by making it into a desired shape in a precursor state and then heating. Polyimide precursors are often unstable with respect to heat and water and have poor storage stability (Non-Patent Document 1). In consideration of this point, a polyimide that has been improved so that it can be molded or applied by dissolving in a solvent after introducing a skeleton with excellent solubility in the molecular structure and making it into a polyimide is used. There is a tendency that the chemical resistance and the adhesion to the substrate are inferior to those of the precursor system. Therefore, a method using a precursor and a method using solvent-soluble polyimide are properly used depending on the purpose.

In addition, there has been a demand for patterning polyimide into a desired shape as technology advances. For this reason, polyimide has also been developed that uses electromagnetic waves such as ultraviolet rays to form patterns through processes such as exposure and development. Several methods have been proposed for patterning polyimide.
One of them is a method of obtaining a polyimide pattern by performing patterning by exposure and development in the state of a polyimide precursor, and then imidizing by heat treatment or the like. The other is that a resist pattern is formed of organic matter, metal, etc. on polyimide itself which is not photosensitive itself, and the opening is formed by a solution of hydrazine, inorganic alkali, organic alkali, etc. or an organic polar solvent, or those The pattern is obtained by treating with a mixture of
The former is superior in processing characteristics by using a precursor excellent in solvent solubility, and the latter has an advantage that it is not necessary to perform an imidization process that requires high-temperature heat treatment after pattern formation. It is properly used according to the purpose.

In the semiconductor field, which has achieved remarkable development since the latter half of the 20th century, patternable polyimides of the type mainly utilizing precursors are currently used. One reason for this is that since the polyimide is formed on the silicon wafer, the substrate can withstand a high-temperature heat treatment of 300 ° C. to 400 ° C. necessary for imidization.
Various methods have also been proposed as means for patterning a type of polyimide that uses a precursor. The typical method is roughly classified into the following two.
(1) A method in which a polyimide precursor itself does not have a patterning capability, a photosensitive resin layer is formed on the surface, and the polyimide precursor is patterned by the pattern of the photosensitive resin.
(2) A method in which a photosensitive site is introduced into the polyimide precursor itself and a pattern is formed by the action, or a photosensitive component is mixed with the polyimide precursor to form a resin composition, and the pattern is formed by the action of the photosensitive component. Technique. Furthermore, it is a technique that combines the introduction of photosensitive sites and the mixing of photosensitive components.

  As a representative method belonging to the group (1) above, utilizing the fact that the polyamic acid that is a polyimide precursor is soluble in an alkaline solution, a resist capable of alkali development is applied on the coating film, After irradiating the electromagnetic wave in the desired shape, simultaneously with developing the resist, the polyamic acid exposed from the opening of the resist appearing in the development is also eluted into the developer to form a pattern, and then an organic solvent such as acetone insoluble in the polyamic acid The surface resist layer is peeled off, followed by imidization to obtain a polyimide pattern.

On the other hand, as representative methods belonging to the group (2) above:
(A) The polyamic acid of the polyimide precursor is mixed with a naphthoquinonediazide derivative that acts as a dissolution inhibitor before exposure to electromagnetic waves and generates a carboxylic acid and serves as a dissolution accelerator after exposure. A method of forming a pattern by increasing the contrast of the dissolution rate of the part with respect to the developer and then imidizing to obtain a polyimide pattern; (Patent Document 1)
(B) The polyamic acid of the polyimide precursor is mixed with a compound such as a dihydropyridine derivative that becomes a basic substance by exposure to electromagnetic waves, and after exposure, the basic substance generated in the exposed portion is heated at an appropriate temperature. The solubility of the exposed area in the developer is improved by the action, and a positive pattern is formed by increasing the contrast of the dissolution rate between the exposed area and the unexposed area of the developer, and then completely imidized. Technique for obtaining a polyimide pattern (Patent Document 2);

(C) A polyimide precursor having a radically polymerizable skeleton having an ethylenically unsaturated bond bonded thereto is mixed with a photoradical generator to form a cross-linked structure in the exposed area, thereby developing the solution. A technique for forming a pattern by reducing the solubility and increasing the contrast of the dissolution rate of the exposed area and the unexposed area to the developer, followed by imidization to obtain a polyimide pattern (Patent Document 3);
(D) The polyimide precursor polyamic acid and the compound having a radically polymerizable ethylenically unsaturated bond having a basic site are mixed to form an ion bond between the two, and the sensitizer is mixed therewith for exposure. A radical pair is formed in the part to reduce the solubility in the developer, and the pattern is formed by increasing the contrast of the dissolution rate in the developer between the exposed part and the unexposed part. (Patent Document 4);
as well as,
(E) The polyamic acid of the polyimide precursor is mixed with a photoacid (or photobase) generator and a crosslinking agent, and after exposure, heating is performed to advance crosslinking by the action of the acid (or base) generated by exposure. The method of obtaining a polyimide pattern by reducing the solubility in a developing solution to increase the contrast of the dissolution rate in the developing solution between the exposed portion and the unexposed portion to form a pattern, followed by imidization;
Etc. have been proposed.

Although the method belonging to the group (1) has a complicated process, the degree of freedom of the composition of the polyimide precursor to be used is large, and since the photosensitive component is not mixed, the final polyimide is other than polyimide. It is characterized by high reliability with no impurities.
On the other hand, in the method belonging to the group (2), since the polyimide precursor (or polyimide precursor resin composition) itself has a pattern forming ability, a resist layer as used in the group (1) is not necessary. The process is greatly simplified. On the other hand, the photosensitive polyimides (c) and (d) are solvent-developed, and there is a problem that the working environment is deteriorated and costs such as the treatment ratio of waste liquid are required. Furthermore, in the photosensitive polyimide (c), since the carboxyl group of the polyamic acid and the (meth) acryloyl group which is a crosslinking component are connected by an ester bond, the polyamic acid is hardly hydrolyzed and has good storage stability. On the other hand, there is a problem that the synthesis route is complicated and the cost is high.

Since the above (a), (b), and (e) can be developed with an alkaline aqueous solution, the above problem does not occur. Among them, the methods (b) and (e) require a heating step after exposure and before development, but the method (a) is a development step as it is after exposure in the same manner as general photosensitive materials. Therefore, the number of processes is reduced by one step and the handling is easy.
As described above, the method (a) is a material that is extremely excellent in handling, but a general polyamic acid has a large solubility in an alkaline aqueous solution because it contains a large amount of carboxyl groups in the skeleton. There was a problem that the difference in dissolution rate of the part with respect to the aqueous alkali solution could not be increased, making pattern formation difficult.

In order to deal with such problems, attempts have been made to control the solubility of polyamic acid in an alkaline aqueous solution to form a pattern.
In Non-Patent Document 2, a positive photosensitivity capable of obtaining a good pattern by combining a polyamic acid in which a hydrophobic skeleton is introduced into a polymer main chain and the solubility in an alkaline aqueous solution is lowered with a compound having an o-quinonediazide skeleton. It is made of conductive polyimide.
Patent Document 5 discloses a method of controlling the dissolution rate in an alkaline aqueous solution by performing partial imidation of polyamic acid by heating when drying after applying the resin composition to a substrate and reducing the carboxyl groups. Yes. Patent Document 6 discloses a positive working photoresist containing a fully esterified polyamic acid prepolymer and a quinonediazide compound. Here, a method has been proposed in which the carboxyl group of the polyamic acid is reduced by esterification to control the solubility in an aqueous alkali solution. Further, in Patent Document 7, a positive photosensitivity using a polyimide precursor in which a polyamic acid is treated with dimethylformamide dimethyl acetal to partially esterify the carboxyl group of the polyamic acid to reduce the solubility in an alkaline aqueous solution. Resin compositions have been proposed.

JP 52-13315 A Japanese Patent Laid-Open No. 6-43648 JP 61-293204 A Japanese Examined Patent Publication No.59-52822 Japanese Patent Laid-Open No. 62-135824 Japanese Patent Laid-Open No. 2-181149 JP 2000-119520 A Kreuz, J. A., “J Polym Sci Part A: Polym Chem”, 1990, 28, p.3787. J. Photopolym. Sci. Technol., 1997, 10, p.55

  However, the method of Non-Patent Document 2 has a problem that the polyimide skeleton that can be used is limited. In the case of the technique of Patent Document 5, since the imidization reaction is a dehydration reaction, heating at 100 ° C. or higher is necessary for efficient progress, whereas the quinonediazide compound that is a photosensitizer used has heat resistance. It is low and gradually decomposes by heating at 100 ° C. or higher, so that it does not function as a photosensitizer. Furthermore, depending on conditions such as the amount of residual solvent, the imidation state easily changes even when heated under the same conditions. There is a problem that a stable pattern cannot be formed. Moreover, in the case of patent document 6, the process which manufactures the esterified polyimide precursor was complicated, and there existed a problem that manufacturing cost was high. In the case of Patent Document 7, dimethylformamide dimethyl acetal is a basic compound, and when it coexists with polyamic acid, it hydrolyzes polyamic acid and causes a decrease in molecular weight. Therefore, the storage stability as a resin composition is improved. There has been a problem that the production cost increases correspondingly when purification is performed by reprecipitation or the like in order to solve the problem.

  The present invention has been accomplished in view of the above circumstances, and its main purpose is to obtain a solubility contrast regardless of the chemical structure of the finally obtained polyimide, and as a result, a sufficient process margin can be maintained. On the other hand, the present invention provides a photosensitive resin composition that can obtain a pattern having a good shape, can be easily synthesized, and is available at a low cost.

The photosensitive resin composition according to the present invention, a polyimide precursor having a repeating unit represented by the following formula (1), a compound that generates a carboxylic acid by the action of light, one or more vinyl ether compounds, and containing the solvent The vinyl ether compound is contained in an amount of 55 parts by weight or more based on 100 parts by weight of the solvent .

(In Formula (1), R ¹ is a tetravalent organic group, R ² is a divalent organic group, and R ¹ and R ² that are repeated may be the same or different. R ³ and R ⁴ are each independently a monovalent organic group having the structure of the following formula (2), and they may be the same or different, and repeated R ³ and R ⁴ are Each may be the same or different.)

(In Formula (2), R ⁵ , R ⁶ , and R ⁷ are each independently hydrogen, a halogen atom, or a monovalent organic group, A is a monovalent organic group, and repeated A's are the same. R ⁵ , R ⁶ , R ⁷ , and A may be bonded to each other to represent a cyclic structure.

The polyimide precursor having a repeating unit represented by the above formula (1) used in the photosensitive resin composition of the present invention has a hemiacetal ester structure due to the reaction of the carboxyl group of the polyamic acid with a vinyl ether compound or the like. Yes. The inventor has examined the hemiacetal ester bond of the polyimide precursor in detail, so that the hemiacetal ester bond is dissociated or hydrolyzed into a polyamic acid and a vinyl ether compound by heating at a relatively low temperature. It has been found that it becomes an acid and a vinyl ether, or an acetaldehyde and an alcohol. Therefore, by utilizing this reaction, the polyimide precursor having the repeating unit represented by the above formula (1) is heated under appropriate conditions to cause the above dissociation reaction or hydrolysis reaction, or partially, All of them can have an amic acid structure. Since the amic acid moiety has a carboxyl group and is highly soluble in a basic solution, it is possible to change the ratio of changing the hemiacetal ester moiety to an amic acid moiety by appropriately adjusting the heating conditions. Become. Combining such a polyimide precursor with controlled solubility in a basic solution and a compound that generates a carboxyl group by the action of light causes a carboxyl group to be generated in the exposed portion, resulting in increased hydrophilicity. Since it is dissolved and the unexposed part remains hydrophobic and does not dissolve in the basic solution, a positive pattern in which the unexposed part remains can be obtained.
Thus, the photosensitive resin composition of the present invention is large regardless of the chemical structure of the polyimide finally obtained by controlling the solubility of the polyimide precursor in the basic solution by a simple method of heating. A solubility contrast can be obtained, and as a result, a pattern having a good shape can be obtained while maintaining a sufficient process margin.

Since the polyimide precursor can be obtained simply by mixing a polyamic acid and a vinyl ether compound and stirring at room temperature, it can be easily obtained at low cost. The reaction of the aromatic carboxylic acid and the vinyl ether compound is slightly different in behavior from the case of the aliphatic carboxylic acid. In many cases, the reaction between an aliphatic carboxylic acid and a vinyl ether compound requires heating or an acid catalyst, but as a result of intensive studies, the inventors have found that an aromatic carboxylic acid and a vinyl ether compound can be obtained only by stirring at room temperature. I found it. Furthermore, by using a solvent that does not contain a nitrogen atom at that time, the reaction yield of the polyamic acid and the vinyl ether compound was dramatically improved, and the carboxyl group of the polyamic acid was almost completely converted to a hemiacetal ester bond. It became possible.
Moreover, since the photosensitive resin composition of this invention contains a vinyl ether compound further, storage stability can be improved.

  In the photosensitive resin composition according to the present invention, the use of a compound having an o-quinonediazide (orthoquinonediazide) group as a compound that generates a carboxylic acid by the action of light enables high sensitivity and large contrast to be obtained. To preferred.

  In the photosensitive resin composition which concerns on this invention, in the said polyimide precursor, at least 1 sort (s) of A in said Formula (2) is a C1-C30 monovalent organic group which does not contain active hydrogen. Is preferable from the viewpoint of storage stability.

  In the photosensitive resin composition according to the present invention, a polyimide precursor in which A in the formula (2) contains two or more organic groups may be used as the polyimide precursor. Further, in A in the formula (2), an organic group group in which the carbon atom bonded to the oxygen atom in A is a primary carbon atom is A1, an organic group group in which the carbon atom is a secondary carbon atom is A2, and a third group. When A3 is an organic group group that is a secondary carbon atom, A is A1 and A2, A1 and A3, A2 and A3, or A1 and A2 and A3 in combination of one or more of each, You may use the polyimide precursor containing. By having a hemiacetal ester bond having a plurality of structures, it becomes easy to control the solubility in a basic solution by heating.

In the photosensitive resin composition according to the present invention, the polyimide precursor is a structure in which R ⁵ , R ⁶ , and R ⁷ in the formula (2) are hydrogen, that is, represented by the following formula (1 ′). A polyimide precursor can be used.

(In Formula (1 ′), R ¹ is a tetravalent organic group, R ² is a divalent organic group, and R ¹ and R ² that are repeated may be the same or different from each other. A is a monovalent organic group, and repeated As may be the same or different.

Moreover, this invention is a photosensitive resin composition containing the polyimide precursor which has a repeating unit represented by the said Formula (1), and the compound which generate | occur | produces carboxylic acid by the effect | action of light, Comprising : The said polyimide precursor The photosensitive resin composition in which at least 1 sort (s) of A in said Formula (2) is a C1-C30 monovalent organic group containing an ether bond is also provided. The photosensitive resin composition, adhesion and storage stability to the substrate, resistance is preferred from the viewpoint of the volatility of repellency, degradation product.
This photosensitive resin composition also preferably contains a vinyl ether compound from the viewpoint of improving storage stability.

  In the photosensitive resin composition of this invention, it is preferable from the point of storage stability that an acidic substance and an amine are not included substantially.

  In the photosensitive resin composition of the present invention, the compound that generates carboxylic acid by the action of light preferably absorbs at least one of electromagnetic waves having wavelengths of 436 nm, 405 nm, and 365 nm from the viewpoint of photosensitivity. .

  In one embodiment of the photosensitive resin composition of the present invention, irradiation sensitivity can be improved by further adding a sensitizing dye. Active hydrogen such as an amino group and a hydroxyl group accelerates the decomposition of the hemiacetal ester bond of the polyimide precursor, and thus impairs the stability of the photosensitive resin composition. Therefore, the sensitizing dye includes amino groups and the like. It is preferable that the active hydrogen is not included in the skeleton.

In the photosensitive resin composition of the present invention, in the polyimide precursor, the formula (1) R ¹ and / or R ² in, be an aromatic ring, the heat resistance of the finally obtained polyimide film It is preferable because it becomes good and the linear thermal expansion coefficient becomes small. Furthermore, since R ¹ in the formula (1) is a skeleton derived from aromatic tetracarboxylic dianhydride, the reaction for forming a hemiacetal bond proceeds rapidly at room temperature without using a catalyst. It is preferable because synthesis is easy.

In the photosensitive resin composition of the present invention, in the polyimide precursor, 33 mol% or more of R ¹ in the formula (1) has any structure represented by the following formula (3). preferable.

The polyamic acid having the structure as described above is not only a polyimide precursor exhibiting high heat resistance and low linear thermal expansion coefficient, but also has an aromatic carboxylic acid, and thus reacts with a vinyl ether compound at room temperature. It is possible to generate hemiacetal ester bonds. Furthermore, the hemiacetal ester bond obtained from the aromatic carboxylic acid as described above is thermally decomposed by heating at a lower temperature than the hemiacetal ester bond obtained from the aliphatic carboxylic acid. There are few decomposition products derived from the vinyl ether in the polyimide finally decomposed quickly. Therefore, the closer the content of the structure represented by the above formula (3) is to 100 mol% of R ^{1 in} the above formula (1), the easier it is to achieve the object of the present invention. The purpose can be achieved by containing 33% or more of R ^{1 in} (1).

In the photosensitive resin composition of the present invention, in the polyimide precursor, 33 mol% or more of R ² in the formula (1) preferably has any structure represented by the following formula (4). .

(R ¹⁴ is a divalent organic group, an oxygen atom, a sulfur atom, or a sulfone group, and R ¹⁵ and R ¹⁶ are a monovalent organic group or a halogen atom.)
When it has the above structure, the heat resistance of the polyimide finally obtained improves. Therefore, the closer to 100 mol% of R ² in the formula (1), the easier it is to achieve the target of the present invention, but at least 33% of R ² in the formula (1) is contained. You can achieve your purpose.

  In the photosensitive resin composition of this invention, it is preferable that the solvent which does not contain a nitrogen atom is included from the point of storage stability.

  The pattern forming method of the present invention comprises a heating step of heating at or after the formation of the film or molded body of the photosensitive resin composition of the present invention, and a predetermined surface on the surface of the film or molded body after the heating step. It has the exposure process which irradiates electromagnetic waves in a pattern form, and the image development process developed using as a basic solution.

  The pattern forming method of the present invention may be a positive pattern forming method in which development is performed using a basic aqueous solution in the developing step.

  In the pattern formation method of this invention, it has the process of heating the said film | membrane or a molded object after the said image development process, and it is preferable that the maximum temperature of the said heating temperature is 251 degreeC or more and 400 degrees C or less. By heating at such a temperature, imidization of the polyimide precursor proceeds sufficiently and substantially all of the carboxylic acid disappears, so that the finally obtained polyimide film has low hygroscopicity and high heat resistance. In addition, there is almost no residual decomposition product derived from the photosensitizing component, and a highly reliable polyimide film can be obtained.

As described above, according to the present invention, a solubility contrast can be obtained only by mixing a polyimide precursor that can be easily synthesized and a photoacid generator, and as a result, a sufficient process margin can be maintained. On the other hand, a pattern having a good shape can be obtained, and a photosensitive resin composition can be obtained at a low cost.
Moreover, if the polyimide precursor has a hemiacetal ester bond, a wide range of structures can be selected because a wide range of polyimide precursors can be selected. Furthermore, depending on the purpose, it is possible to select a compound that generates a carboxylic acid by the action of many types of light, and there are many options for the structure as a photosensitive resin composition.
In addition, since the developer is also low in environmental pollution and can use an inexpensive basic aqueous solution, it is highly industrially useful.

The present invention will be described in detail below.
In the present invention, the electromagnetic wave only needs to be capable of causing an intramolecular cleavage reaction of the compound, and not only electromagnetic waves having wavelengths in the visible and invisible regions, but also particle beams such as electron beams, and This includes radiation or ionizing radiation that collectively refers to electromagnetic waves and particle beams.
The photosensitive resin composition according to the present invention contains a polyimide precursor having a repeating unit represented by the following formula (1) and a compound that generates carboxylic acid by the action of light.

(In Formula (1), R ¹ is a tetravalent organic group, R ² is a divalent organic group, and R ¹ and R ² that are repeated may be the same or different. R ³ and R ⁴ are each independently a monovalent organic group having the structure of the following formula (2), and they may be the same or different, and repeated R ³ and R ⁴ are Each may be the same or different.)

(In Formula (2), R ⁵ , R ⁶ , and R ⁷ are each independently hydrogen, a halogen atom, or a monovalent organic group, A is a monovalent organic group, and repeated A's are the same. R ⁵ , R ⁶ , R ⁷ , and A may be bonded to each other to represent a cyclic structure.

The present inventor aims to obtain a photosensitive polyimide which has little residue of components other than polyimide after imidization and has good storage stability at room temperature, and is easily cleaved by heating to generate a carboxyl group. Research focused on the acetal ester bond.
As a result, it was confirmed that the polyimide precursor obtained by converting the carboxyl group of the polyamic acid into a hemiacetal ester was decomposed into a polyamic acid by heating to decompose the hemiacetal ester bond. There are two types of decomposition: a case where the hemiacetal ester bond is cleaved into a polyamic acid and a vinyl ether compound, and a case where the hemiacetal ester bond is coexistent with water to be hydrolyzed to become a polyamic acid, acetaldehyde and an alcohol. The state of was observed.
Further, the temperature at which the hemiacetal ester bond is decomposed depends on the chemical structure of the site bonded to the hemiacetal ester bond. For example, the carbon atom bonded to the ether oxygen is a primary carbon atom (hereinafter simply referred to as “primary carbon atom”). In the case of “secondary carbon atom” (hereinafter sometimes simply referred to as “secondary”) and tertiary carbon atom (hereinafter simply referred to as “tertiary”). There was a tendency for the decomposition temperature to decrease. In the present invention, a carbon atom bonded to an ether bond in a hemiacetal ester bond (a carbon atom bonded to an oxygen atom in A in formula (2)) or an ether bond of a vinyl ether compound that induces a hemiacetal ester bond As for the carbon atom bonded to, the primary carbon atom means the case where there are 0 or 1 other carbon atom bonded, and the secondary carbon atom means the other carbon atom bonded. Is a case where the number of carbon atoms is two, and the tertiary carbon atom means a case where there are three other carbon atoms bonded.

  From these findings, the inventor can control the solubility in a basic solution by converting a carboxyl group of a polyamic acid into a hemiacetal ester and partially decomposing the hemiacetal ester bond by heating to form a carboxylic acid. I thought it would be possible. And it thought that the photosensitive polyimide which can form a pattern with favorable contrast could be created by combining this polyimide precursor and an orthoquinone diazide compound, and earnestly examined and came to this invention.

The hemiacetal ester bond is easily pyrolyzed only by heating as compared with the conventional ester bond, and the bond is cleaved by heating at a relatively low temperature. Many polyimide precursors are generally said to undergo imidization gradually from a temperature in the vicinity of 140 ° C. with heating, and the glass transition temperature (Tg) of the film increases as the imidization rate increases. To go. When Tg increases, the vibration of the molecular chain is suppressed, so that it is difficult to volatilize the substance from the inside of the film. On the other hand, in the case of a hemiacetal ester bond, since it decomposes from around room temperature in some cases, the decomposition reaction occurs with a low imidation rate. Therefore, when the hemiacetal ester bond is combined with the polyimide precursor, the volatility of the decomposition component is good, and almost all of the hemiacetal ester bond is decomposed during the heating process when the polyimide precursor is converted to polyimide. The decomposition component volatilizes. As a result, since it becomes substantially polyamic acid, it exhibits almost the same behavior as polyamic acid which is a polyimide precursor generally used in the past in the process of imidization. In addition, by appropriately selecting a component other than polyamic acid (hereinafter referred to as a protected site) generated by decomposition of the hemiacetal ester bond, the finally obtained polyimide film is decomposed from the hemiacetal ester bond component. It is possible to obtain a product with almost no remaining material.
Considering such points, it is preferable that the protected site has a low molecular weight and a high volatility of the structure after decomposition from the viewpoint of suppressing the remaining of the decomposition product on the polyimide film.
Further, it is preferable that the protective site does not substantially contain a crosslinkable (reactive) site because gelation during synthesis of the polyimide precursor can be suppressed, and further, residue in the film can be suppressed.

  Since the polyimide precursor can be obtained simply by mixing a polyamic acid and a vinyl ether compound and stirring at room temperature, it can be easily obtained at low cost. The reaction of the aromatic carboxylic acid and the vinyl ether compound is slightly different in behavior from the case of the aliphatic carboxylic acid. In many cases, the reaction between an aliphatic carboxylic acid and a vinyl ether compound requires heating or an acid catalyst, but as a result of intensive studies, the inventors have found that an aromatic carboxylic acid and a vinyl ether compound can be obtained only by stirring at room temperature. I found it. In addition, by using a solvent that does not contain a nitrogen atom, the reaction yield of the polyamic acid and the vinyl ether compound was dramatically improved, and the carboxyl group of the polyamic acid was almost completely converted to a hemiacetal ester bond. It became possible.

The photosensitive resin composition containing the polyimide precursor having the hemiacetal ester bond and a compound that generates carboxylic acid by the action of light can obtain a pattern by the following method.
After apply | coating the solution of the said photosensitive resin composition on a board | substrate, it heats and dries and obtains a coating film. At that time, it is possible to adjust the decomposition rate of the hemiacetal ester bond of the polyimide precursor by appropriately setting the heating conditions. At this time, the optimal decomposition rate for pattern formation varies depending on the chemical structure of the main chain skeleton of the polyimide precursor, but the dissolution rate of the coating film of the polyimide precursor alone in the developer is 0.1 nm / s to 100 nm / When the decomposition rate is set in the range of s, preferably in the range of 0.5 nm / s to 50 nm / s, more preferably in the range of 1 nm / s to 20 nm / s, a good pattern can be obtained.
The polyimide precursor film in which a part (or all) of the hemiacetal ester bond formed on the substrate is decomposed to become a carboxyl group is passed through a mask on which a pattern of a desired shape is drawn. By performing exposure, carboxylic acid can be generated only in the exposed portion. Here, the compound that generates carboxylic acid by the action of light has the function of generating carboxylic acid and increasing the solubility of the light irradiated part in the basic solution, and the basicity of the polyimide precursor in the light irradiated part. It works to promote dissolution in solution.
Thus, since the solubility with respect to a basic solution changes in an exposed part and an unexposed part, the positive pattern which an exposed part melt | dissolves and an unexposed part does not melt | dissolve can be obtained.

As the compound that generates carboxylic acid by the action of light in the photosensitive resin composition of the present invention, a compound having an o-quinonediazide group is preferably used. A compound having an o-quinonediazide group has a large change in hydrophobicity and hydrophilicity before and after exposure, and has a wide light absorption band and high sensitivity. In addition, many types are commercially available and are easily available.
Thus, the photosensitive resin composition of the present invention, which combines a hemiacetal ester bond and a compound that generates carboxylic acid by the action of light, can also have the merit of high sensitivity and low cost.

The polyimide precursor in which the carboxyl group used in the present invention is converted into a hemiacetal ester can be obtained at a very low cost because it is obtained simply by mixing a polyamic acid and a vinyl ether compound. Furthermore, it is possible to adjust the photosensitive resin composition by a simple method of mixing a compound that generates carboxylic acid by the action of light, such as a compound having a polyimide precursor and an o-quinonediazide group.
Furthermore, the selection range of the applicable polyimide precursor is wide, and it is widely applied to the field where the characteristics of the photosensitive resin composition and the imidized product can be utilized.

Next, each component used for the photosensitive resin composition of this invention is demonstrated.
The polyimide precursor used in the present invention has a repeating unit represented by the following formula (1).

(In Formula (1), R ¹ is a tetravalent organic group, R ² is a divalent organic group, and R ¹ and R ² that are repeated may be the same or different. R ³ and R ⁴ are each independently a monovalent organic group having the structure of the following formula (2), and they may be the same or different, and repeated R ³ and R ⁴ are Each may be the same or different.)

(In formula (2), R ⁵ , R ⁶ , and R ⁷ are each independently hydrogen, a halogen atom, or a monovalent organic group, A is a monovalent organic group, and repeated A's are the same. R ⁵ , R ⁶ , R ⁷ and A may be bonded to each other to represent a cyclic structure.

In the formula (1), generally, R ¹ is a structure derived from tetracarboxylic dianhydride, and R ² is a structure derived from diamine.
Examples of the acid dianhydride applicable to the polyimide precursor of the present invention include ethylene tetracarboxylic dianhydride, butane tetracarboxylic dianhydride, cyclobutane tetracarboxylic dianhydride, and cyclopentane tetracarboxylic dianhydride. , Pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 2,2 ′, 6,6′-biphenyltetracarboxylic dianhydride, 2 , 2-bis (3,4-dicarboxyphenyl) propane dianhydride, 2,2-bis (2,3-dicarboxyphenyl) propane dianhydride, bis (3,4-dicarboxyphenyl) Ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, bis (2,3-dicarboxyphenyl) methane Dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane Anhydride, 2,2-bis (2,3-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoropropane dianhydride, 1,3-bis [(3,4-dicarboxy ) Benzoyl] benzene dianhydride, 1,4-bis [(3,4-dicarboxy) benzoyl] benzene dianhydride, 2,2-bis {4- [4- (1,2-dicarboxy) phenoxy] Phenyl} propane dianhydride,

2,2-bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} propane dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride Bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, 4,4′-bis [4- (1,2-dicarboxy) phenoxy] biphenyl dianhydride, 4,4′-bis [3- (1,2-dicarboxy) phenoxy] biphenyl dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, bis { 4- [3- (1,2-dicarboxy) phenoxy] phenyl} ketone dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} sulfone dianhydride, bis {4- [3- (1,2-dicarbox ) Phenoxy] phenyl} sulfone dianhydride, bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} sulfide dianhydride, bis {4- [3- (1,2-dicarboxy) phenoxy ] Phenyl} sulfide dianhydride, 2,2-bis {4- [4- (1,2-dicarboxy) phenoxy] phenyl} -1,1,1,3,3,3-hexafulpropane dianhydride 2,2-bis {4- [3- (1,2-dicarboxy) phenoxy] phenyl} -1,1,1,3,3,3-propane dianhydride, 2,3,6,7- Naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,2,3,4-benzenetetra Carboxylic dianhydride, 3,4,9,10 -Perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride and the like.
These may be used alone or in combination of two or more.

The tetracarboxylic dianhydride preferably used from the viewpoints of the heat resistance, linear thermal expansion coefficient of the finally obtained polyimide film and the reactivity of the protective reaction to the precursor is an aromatic tetracarboxylic dianhydride. It is preferable that there are particularly preferred tetracarboxylic dianhydrides, such as pyromellitic dianhydride, merophanic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 3,3. ', 4,4'-biphenyltetracarboxylic dianhydride, 2,3,3', 4'-biphenyltetracarboxylic dianhydride, 2,3,2 ', 3'-biphenyltetracarboxylic dianhydride 2,2 ′, 6,6′-biphenyltetracarboxylic dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1 , 1 1,3,3,3-hexafluoropropane dianhydride and bis (3,4-dicarboxyphenyl) ether dianhydride.
Among these, from the viewpoint of the stability of the hemiacetal ester bond, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride and bis (3,4-dicarboxyphenyl) ether dianhydride are particularly preferred.

  When an acid dianhydride into which fluorine is introduced or an acid dianhydride having an alicyclic skeleton is used as the acid dianhydride to be used in combination, the transparency of the polyimide precursor is improved. In addition, pyromellitic dianhydride, merophanic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride When rigid acid dianhydrides such as 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride are used, it is finally obtained. Since the linear thermal expansion coefficient of the polyimide obtained becomes small, it is preferable. Among these, from the viewpoint of the stability of the hemiacetal ester bond, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 2,3,2 ′, 3′-biphenyltetracarboxylic dianhydride is particularly preferred.

  When the acid dianhydride has an alicyclic skeleton, the transparency of the polyimide precursor is improved, so that a highly sensitive photosensitive resin composition is obtained. Furthermore, heating or a catalyst may be required in the reaction for forming the hemiacetal ester bond, but since it is possible to form a hemiacetal ester bond having a relatively high stability, emphasis is placed on storage stability. The case is preferred.

On the other hand, when aromatic tetracarboxylic dianhydride is used, it becomes the photosensitive resin composition which is excellent in heat resistance and shows a low linear thermal expansion coefficient. Furthermore, since the reaction for forming a hemiacetal ester bond proceeds at room temperature, the target polyimide precursor can be obtained very easily. Furthermore, since it decomposes at a lower temperature, there is an advantage that the decomposition product hardly remains in the film after imidization. Therefore, in the photosensitive resin composition of the present invention, in the polyimide precursor, 33 mol% or more of R ¹ in the formula (1) is any structure represented by the following formula (3). It is preferable.

The polyamic acid having the structure as described above is not only a polyimide precursor exhibiting high heat resistance and low linear thermal expansion coefficient, but also has an aromatic carboxylic acid, and thus reacts with a vinyl ether compound at room temperature. It is possible to generate hemiacetal ester bonds. Furthermore, the hemiacetal ester bond obtained from the aromatic carboxylic acid as described above is thermally decomposed by heating at a lower temperature than the hemiacetal ester bond obtained from the aliphatic carboxylic acid. There are few decomposition products derived from the vinyl ether in the polyimide finally decomposed quickly. Therefore, the closer the content of the structure represented by the above formula (3) is to 100 mol% of R ^{1 in} the above formula (1), the easier it is to achieve the object of the present invention. The purpose can be achieved by containing 33% or more of R ^{1 in} (1). Among them, the content of the structure represented by the above formula (3) is preferably 50 mol% or more, and more preferably 70 mol% or more of R ¹ in the formula (1).

On the other hand, the diamine component applicable to the polyimide precursor of the present invention can be used alone or in combination of two or more diamines. The diamine component used is not limited, but p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 4,4′-diamino. Diphenyl ether, 3,3′-diaminodiphenyl sulfide, 3,4′-diaminodiphenyl sulfide, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfone, 3,4′-diaminodiphenyl sulfone, 4,4 '-Diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone,
3,4′-diaminobenzophenone, 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenylmethane, 3,4′-diaminodiphenylmethane, 2,2-di (3-aminophenyl) propane, 2,2-di (4-aminophenyl) propane, 2- (3-aminophenyl) -2- (4-aminophenyl) propane, 2,2-di (3-aminophenyl) -1,1,1,3,3,3 -Hexafluoropropane, 2,2-di (4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 2- (3-aminophenyl) -2- (4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 1,1-di (3-aminophenyl) -1-phenylethane, 1,1-di (4-aminophenyl) -1-phenylethane , 1- ( 3-aminophenyl) -1- (4-aminophenyl) -1-phenylethane, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4- Bis (3-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (3-aminobenzoyl) benzene, 1,3-bis (4-aminobenzoyl) benzene, 1, 4-bis (3-aminobenzoyl) benzene, 1,4-bis (4-aminobenzoyl) benzene, 1,3-bis (3-amino-α, α-dimethylbenzyl) benzene, 1,3-bis (4 -Amino-α, α-dimethylbenzyl) benzene, 1,4-bis (3-amino-α, α-dimethylbenzyl) benzene, 1,4-bis (4-amino-α, α-dimethylbenzyl) L) benzene, 1,3-bis (3-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,3-bis (4-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,4- Bis (3-amino-α, α-ditrifluoromethylbenzyl) benzene, 1,4-bis (4-amino-α, α-ditrifluoromethylbenzyl) benzene, 2,6-bis (3-aminophenoxy) benzo Nitrile, 2,6-bis (3-aminophenoxy) pyridine, 4,4′-bis (3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, bis [4- (3- Aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [ - (4-aminophenoxy) phenyl] sulfide,

Bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-amino) Phenoxy) phenyl] ether, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [3- (3-Aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3 3,3-hexafluoropropane, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (4-aminophenoxy) benzoyl] ben 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,4-bis [4- (4-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-amino Phenoxy) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, 1,4-bis [4- (3-aminophenoxy) -Α, α-dimethylbenzyl] benzene, 1,4-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, 4,4'-bis [4- (4-aminophenoxy) benzoyl ] Diphenyl ether, 4,4′-bis [4- (4-amino-α, α-dimethylbenzyl) phenoxy] benzophenone, 4,4′-bis [4- (4-amino-α, α-dimethylbenzen) ) Phenoxy] diphenylsulfone, 4,4′-bis [4- (4-aminophenoxy) phenoxy] diphenylsulfone, 3,3′-diamino-4,4′-diphenoxybenzophenone, 3,3′-diamino-4 , 4′-Dibiphenoxybenzophenone, 3,3′-diamino-4-phenoxybenzophenone, 3,3′-diamino-4-biphenoxybenzophenone, 6,6′-bis (3-aminophenoxy) -3,3 3 ′, 3′-tetramethyl-1,1′-spirobiindane, 6,6′-bis (4-aminophenoxy) -3,3,3 ′, 3′-tetramethyl-1,1′-spirobiindane, , 3-bis (3-aminopropyl) tetramethyldisiloxane, 1,3-bis (4-aminobutyl) tetramethyldisiloxane, α, ω-bis ( -Aminopropyl) polydimethylsiloxane, α, ω-bis (3-aminobutyl) polydimethylsiloxane, bis (aminomethyl) ether, bis (2-aminoethyl) ether, bis (3-aminopropyl) ether, bis ( 2-aminomethoxy) ethyl] ether, bis [2- (2-aminoethoxy) ethyl] ether, bis [2- (3-aminoprotoxy) ethyl] ether,

1,2-bis (aminomethoxy) ethane, 1,2-bis (2-aminoethoxy) ethane,
1,2-bis [2- (aminomethoxy) ethoxy] ethane, 1,2-bis [2- (2-aminoethoxy) ethoxy] ethane, ethylene glycol bis (3-aminopropyl) ether, diethylene glycol bis (3- Aminopropyl) ether, triethylene glycol bis (3-aminopropyl) ether, ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7 -Diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane, 1,2-diaminocyclohexane, 1,3-diamino Cyclohexane, 1,4-diaminocyclohexane, 1,2-di 2-aminoethyl) cyclohexane, 1,3-di (2-aminoethyl) cyclohexane, 1,4-di (2-aminoethyl) cyclohexane, bis (4-aminocyclohexyl) methane, 2,6-bis ( Aminomethyl) bicyclo [2.2.1] heptane, 2,5-bis (aminomethyl) bicyclo [2.2.1] heptane, and some or all of the hydrogen atoms on the aromatic ring of the diamine are fluoro groups. A diamine substituted with a substituent selected from a methyl group, a methoxy group, a trifluoromethyl group, or a trifluoromethoxy group can also be used.
Furthermore, depending on the purpose, any one or two or more of the ethynyl group, benzocyclobuten-4′-yl group, vinyl group, allyl group, cyano group, isocyanate group, and isopropenyl group serving as a crosslinking point, Even if it introduce | transduces into some or all of the hydrogen atoms on the aromatic ring of diamine as a substituent, it can be used.

The diamine can be selected depending on the desired physical properties. If a rigid diamine such as p-phenylenediamine is used, the finally obtained polyimide has a low expansion coefficient. Rigid diamines include p-phenylenediamine, m-phenylenediamine, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2, 6 as diamines in which two amino groups are bonded to the same aromatic ring. -Diaminonaphthalene, 2,7-diaminonaphthalene, 1,4-diaminoanthracene and the like can be mentioned.
In addition, diamines in which two or more aromatic rings are bonded by a single bond, and two or more amino groups are each bonded directly or as part of a substituent on a separate aromatic ring, for example, There exists what is represented by following formula (5). Specific examples include benzidine and the like.

(A is a natural number of 1 or more, and an amino group is bonded to a meta position or a para position with respect to a bond between benzene rings. R ¹⁷ and R ¹⁸ are a monovalent organic group or a halogen atom.)

Furthermore, in the above formula (5), a diamine having a substituent at a position where the amino group on the benzene ring is not substituted and which does not participate in the bond with another benzene ring can also be used. These substituents are monovalent organic groups, but they may be bonded to each other.
Specific examples include 2,2′-dimethyl-4,4′-diaminobiphenyl, 2,2′-ditrifluoromethyl-4,4′-diaminobiphenyl, 3,3′-dichloro-4,4′-diamino. Biphenyl, 3,3′-dimethoxy-4,4′-diaminobiphenyl, 3,3′-dimethyl-4,4′-diaminobiphenyl and the like can be mentioned.
When the finally obtained polyimide is used as an optical waveguide or an optical circuit component, the transmittance for electromagnetic waves having a wavelength of 1 μm or more can be improved by introducing fluorine as a substituent of the aromatic ring.

  On the other hand, when a diamine having a siloxane skeleton such as 1,3-bis (3-aminopropyl) tetramethyldisiloxane is used as the diamine, the elastic modulus of the finally obtained polyimide is lowered and the glass transition temperature is lowered. be able to.

  Here, the selected diamine is preferably an aromatic diamine from the viewpoint of heat resistance. However, depending on the desired physical properties, the diamine may be an aliphatic diamine or siloxane within a range not exceeding 60 mol%, preferably not exceeding 40 mol%. Non-aromatic diamines such as diamines may be used.

Moreover, in the said polyimide precursor, it is preferable that 33 mol% or more among R < ² > in said Formula (1) is one of the structures represented by following formula (4).

(R ¹⁴ is a divalent organic group, an oxygen atom, a sulfur atom, or a sulfone group, and R ¹⁵ and R ¹⁶ are a monovalent organic group or a halogen atom.)

When it has the above structure, the heat resistance of the polyimide finally obtained improves. Therefore, the closer to 100 mol% of R ² in the formula (1), the easier it is to achieve the target of the present invention, but at least 33% of R ² in the formula (1) is contained. You can achieve your purpose. Of these the content of the structure represented by the above formula (4) is preferably the at formula (1) 50 mol% or more of R ² in, it is more preferably 70 mol% or more.

On the other hand, in the formula (1), R ³ and R ⁴ are each independently a monovalent organic group having the structure of the above formula (2), and they may be the same or different, and repeat R ³ and R ⁴ may be the same or different.
The hemiacetal ester bond represented by the above formula (2) can be obtained by, for example, the following reaction between a carboxyl group and a vinyl ether compound.

That is, when a hemiacetal ester bond is formed by an addition reaction between a carboxylic acid and a vinyl ether compound, R ⁵ , R ⁶ , R ⁷ and A in the above formula (2) are determined by the structure of the vinyl ether compound. The structure represented by the above formula (2) may be formed using a cyclic vinyl ether compound such as dihydropyran (a compound in which vinyl ether itself is part of the ring), but in this case, the reactivity is poor, While the reaction time is increased, the thermal decomposition temperature is relatively high. Therefore, when a non-cyclic vinyl ether compound and a cyclic vinyl ether compound are mixed and used, there is an advantage that hemiacetal ester bonds having different thermal decomposition temperatures are easily formed. Here, the cyclic vinyl ether compound is a compound such as 3,4-dihydro-2H-pyran in which the vinyl bond itself of vinyl ether is part of the ring structure. For example, cyclohexyl vinyl ether, 2-vinyloxytetrahydropyran, and the like have a ring structure, but a vinyl group is not part of the ring structure, and thus becomes an acyclic vinyl ether.

R ⁵ , R ⁶ and R ⁷ are preferably hydrogen or a substituted or unsubstituted alkyl group, allyl group or aryl group. In particular, hydrogen is preferable because of easy availability of raw materials. Moreover, it is preferable that the substituent which has active hydrogens, such as a primary, secondary, tertiary amino group, and a hydroxyl group, is not included.
The substituent having active hydrogen in this case is a substituent that can exchange with a hemiacetal ester bond, and specifically includes a hydroxyl group, a primary amino group, a secondary amino group, a carboxyl group, a mercapto group, and the like. (Chemical Dictionary Tokyo Chemical Doujin)

  A in the above formula (2) is a monovalent organic group having 1 or more carbon atoms. A is exemplified by a group having a hydrocarbon skeleton. They may contain bonds or substituents other than hydrocarbons such as heteroatoms, or such heteroatoms may be incorporated into an aromatic ring to form a heterocycle. Examples of the group having a hydrocarbon skeleton include a linear or branched or alicyclic saturated or unsaturated hydrocarbon group, a linear or branched saturated or unsaturated halogenated alkyl group, or phenyl and naphthyl. And further a group containing an ether bond in a linear or branched saturated or unsaturated hydrocarbon skeleton (for example,-(RO) n-R ', wherein R and R' Is a substituted or unsubstituted saturated or unsaturated hydrocarbon, n is an integer greater than or equal to 1; -R "-(O-R" ') m, where R "and R"' are substituted or unsubstituted saturated or unsaturated Saturated hydrocarbon, m is an integer of 1 or more,-(O-R "') m is bonded to a carbon different from the terminal of R"; and the like), linear or branched saturated or A group containing a thioether bond in an unsaturated hydrocarbon skeleton, linear or branched saturated or unsaturated Examples include various groups formed by bonding a hetero atom or a group containing a hetero atom such as a halogen atom, a cyano group, a silyl group, a nitro group, an acetyl group, an acetoxy group, and a sulfone group on a sum hydrocarbon skeleton.

When a primary, secondary, or tertiary amino group or a substituent having an active hydrogen such as a hydroxyl group is included, the hemiacetal ester bond is likely to be decomposed, so that the storage stability is lowered. Therefore, the above formula (2) It is preferable that A of this does not contain active hydrogen.
Furthermore, A in the above formula (2) tends to have poor storage stability when a reactive group such as an ethylenically unsaturated bond having reactivity is included. Therefore, even if it contains a reactive unsaturated bond, a small amount is preferable, and the repeating unit containing a reactive group in A of the above formula (2) is represented by the formula (1). It is preferable that it is 35 mol% or less in all the repeating units. On the other hand, from the viewpoint of making it difficult for the decomposition product of A after the hemiacetal ester bond is cleaved to remain in the polyimide film, it is preferable that A in the above formula (2) does not contain a reactive group. In addition to the ethylenically unsaturated bond, the reactive group includes a glycidyl group, an oxetanyl group, and an isocyanuric group.

  A in the formula (2) preferably contains an ether bond in the hydrocarbon skeleton from the viewpoints of adhesion to a substrate, storage stability, repellency, and volatility of decomposition products. It may contain a polyoxyalkylene skeleton. When the polyoxyalkylene skeleton is included, the number of repeating oxyalkylenes is preferably 15 or less from the viewpoint of the volatility of the decomposition product.

The hemiacetal ester bond is decomposed into carboxylic acid and other products by heating, and the decomposition temperature is generally such that in A in the above formula (2), the carbon bonded to the oxygen atom is tertiary carbon <secondary. It becomes higher in the order of the substituent of carbon <primary carbon.
On the other hand, the reaction between a vinyl ether compound and a carboxylic acid to obtain a hemiacetal ester bond is generally performed by substituting primary carbon <secondary carbon <tertiary carbon for the carbon bonded to the oxygen atom in A in the above formula (2). High reaction rate in the order of groups.

Therefore, in the case of A in the above formula (2), when the carbon bonded to the oxygen atom is primary carbon, the polyimide precursor has high stability and can withstand long-term storage. Furthermore, since the heating temperature during the process such as film formation can be set higher, the stability during the process is improved.
In A of the above formula (2), when the carbon bonded to the oxygen atom is tertiary carbon, the hemiacetal ester bond is decomposed by heating at a lower temperature, although the polyimide precursor becomes slightly unstable. Therefore, in the process of heating for imidization, the hemiacetal ester bond is more smoothly decomposed and the decomposed product is volatilized, and the protective group in the polyimide film finally obtained even in shorter time heating The amount of residual components of the decomposition product of the above can be reduced, and in many cases can be substantially zero. In addition, when it is desired to obtain a polyimide precursor having a hemiacetal ester bond in a short reaction time, A is preferably a tertiary substituent.
In A of the above formula (2), when the carbon bonded to the oxygen atom is a secondary carbon, it exhibits the characteristics between the case of the primary carbon and the case of the tertiary carbon, and the storage stability of the polyimide precursor, It is possible to provide a photosensitive resin composition having a balance between the detachability of the protecting group and the reactivity to the hemiacetal ester bond.

  A in Formula (2) preferably has 1 to 30 carbon atoms in view of the volatility of the decomposition product, and more preferably 2 to 15 carbon atoms.

  In the structure of A in the above formula (2), it is preferably a monovalent organic group having 1 to 30 carbon atoms containing an ether bond, and further contains no active hydrogen but carbon containing an ether bond. A monovalent organic group having a number of 1 to 30 is preferable.

A in the formula (2) is not particularly limited, and examples thereof include a methyl group, an ethyl group, an ethynyl group, a propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an n-hexyl group, a cyclohexyl group, Cyclohexylmethyl group, methoxyethyl group, ethoxyethyl group, propoxyethyl group, butoxyethyl group, cyclohexyloxyethyl group, methoxypropyl group, ethoxypropyl group, propoxypropyl group, butoxypropyl group, cyclohexyloxypropyl group, 2-tetrahydropyrani And the like. Examples of the structure in which A and R ⁵ are linked in the formula (2) include those in which the substituents corresponding to R ³ and R ⁴ are 2-tetrahydropyranyl groups.

  Moreover, it is good also as a mixture by combining suitably what has 2 or more types of chemical structures as A in said Formula (2). By doing in this way, it becomes possible to control the decomposition rate of the hemiacetal ester bond by heating more stably. That is, since the decomposition temperature of the hemiacetal ester bond varies depending on the chemical structure of the protected site, when the polyimide precursor has multiple types of protected sites, the temperature corresponding to the chemical structure of the protected site that decomposes at a lower temperature It is possible to control the decomposition rate of the protected site stepwise in a manner corresponding to the rate of introduction of the protected site.

As described above, when a protective site with high heat resistance is combined with a low protective site, the temperature is lower than the decomposition temperature of the protective site with high heat resistance and higher than the decomposition temperature of the protective site with low heat resistance. It is possible to selectively decompose only the protected sites with low heat resistance by heating with. In other words, by performing heating under conditions where the difference in decomposition rate when heated under the same conditions is large, it is possible to selectively decompose only protected sites with low heat resistance. Therefore, when combining two or more kinds of protected sites, that is, when A in the formula (2) contains two or more kinds of organic groups, for example, there is a difference in the decomposition rate of at least two kinds of hemiacetal bonds under the same heating conditions. , 30% or more is preferably selected, more preferably 50% or more, and even more preferably 70% or more.
Examples of the heating conditions include a case where a 1 wt% heavy DMSO solution of a polyimide precursor is heated in an NMR tube, a case where the polyimide precursor is applied on an alkali-free glass having a thickness of 800 μm, and heated by a hot plate. The measuring method is determined from the integration ratio of the hydrogen peak derived from the hemiacetal ester bond by NMR and the hydrogen peak of the aromatic ring or amide group, the integration ratio of the peak derived from vinyl ether by IR spectrum, or the like.

  In this way, when a protective site with high heat resistance and a low protective site are combined, the ratio of carboxyl groups after heating can be controlled by the introduction rate of the protective sites with low heat resistance. In the polyimide precursor, the proportion of carboxyl groups is one of the important factors that determine the dissolution rate in basic solutions, and because the proportion of carboxyl groups can be controlled with good reproducibility, a good pattern can be stably obtained, making it practical. Improves.

  In A in the formula (2), the organic group group in which the carbon atom bonded to the oxygen atom in A is a primary carbon atom is A1, the organic group group in which the carbon atom is a secondary carbon atom is A2, and the tertiary carbon atom When A3 represents an organic group group that is an atom, A includes two or more organic groups obtained by combining one or more of A1 and A2, A1 and A3, A2 and A3, or A1, A2, and A3. It is good also as a mixture. Thus, when two or more types having different carbon series are included as A, the difference in the reactivity of the starting vinyl ether compound and the difference in the thermal decomposition temperature of the hemiacetal ester bond become relatively large. As a result, the introduction ratio of two or more different hemiacetal ester bonds can be controlled more stably. Moreover, it becomes possible to control the decomposition rate of the hemiacetal ester bond by heating more stably.

  As described above, generally, when the carbon bonded to the oxygen atom of A is primary (A1), the thermal stability is high, and the thermal stability decreases in the order of secondary (A2) and tertiary (A3). Therefore, for example, by combining the protective sites so as to be a combination of the first grade (A1) and the second grade (A2) and / or the third grade (A3), it becomes possible to selectively decompose the protected sites by heating, A more stable pattern can be formed.

However, if the structure is selected so that the difference in the decomposition temperature of the hemiacetal bond can be appropriately obtained, A in the formula (2) is selected from A1, A2 or A3, and combined. Also good.
The organic group A1 in which the carbon atom bonded to the oxygen atom in A is a primary carbon atom includes, for example, organic groups represented by the following formulas (6-1) and (6-1 ′), The organic group A2 which is a secondary carbon atom includes an organic group represented by the following formula (6-2), for example, and the organic group A3 which is a tertiary carbon atom is represented by the following formula (6-3), for example. ) Is included.

(In the formulas (6-1) to (6-3), R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , and R ¹³ are monovalent organic groups, and X is independently hydrogen, halogen, An atom, an alkoxycarbonyl group, an acyloxy group, an optionally substituted benzoyloxy group, an alkylthio group, an optionally substituted phenylthio group, or an alkoxy group, wherein R ⁸ and X are bonded to each other; R ⁹ , R ¹⁰ and X may be bonded to each other to indicate a cyclic structure, and R ¹¹ , R ¹² and R ¹³ are bonded to each other to form a cyclic structure. May be shown.)

In the above formulas (6-1) to (6-3), R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , and R ¹³ are monovalent organic groups. To carbon atoms in (6-3). Examples of R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , and R ¹³ include groups having a hydrocarbon skeleton. They may contain bonds or substituents other than hydrocarbons such as heteroatoms, or such heteroatoms may be incorporated into an aromatic ring to form a heterocycle. Examples of the group having a hydrocarbon skeleton include the same groups as those described in A above.

Examples of R ⁹ and R ¹⁰ that are bonded to each other to show a cyclic structure include a cyclohexyl group, and R ¹¹ , R ¹² , and R ¹³ are also bonded to each other to show a cyclic structure. Examples thereof include an adamantyl group.

On the other hand, in the above formulas (6-1) to (6-3), X is independently hydrogen, halogen atom, alkoxycarbonyl group, acyloxy group, benzoyloxy group which may have a substituent, alkylthio group, substituted A phenylthio group which may have a group, or an alkoxy group. Examples of the hydrocarbon group bonded to the alkoxycarbonyl group (—COOR), acyloxy group (—OCOR), and alkoxy group (—OR) include a linear, branched, or alicyclic saturated or unsaturated hydrocarbon group. . As the alkoxy group, for example, the above R ⁸ may be bonded to each other to show a cyclic ether structure so that A in the formula (2) becomes a 2-tetrahydropyranyl group.
From the viewpoint of easy availability of raw materials, X in the above formulas (6-1) to (6-3) is preferably hydrogen or an alkoxy group.

  Moreover, the polyimide precursor which introduce | transduced the protection site | part which has 2 or more types of chemical structures can be synthesize | combined by making the vinyl ether and polyamic acid which have 2 or more types of chemical structures react stepwise or at once. .

  Examples of the method for producing the polyimide precursor contained in the photosensitive resin composition of the present invention include a method in which a polyamic acid as a precursor is synthesized from an acid dianhydride and a diamine, and a vinyl ether compound is reacted therewith. Although it is mentioned, it is not limited to this. Tetracarboxylic acid may be reacted with 2 equivalents of a vinyl ether compound to obtain a dicarboxydihemiacetal ester compound, and then polymerized by a dehydration condensation reaction with diamine. In addition, a conventionally known method can be applied.

  The polyimide precursor is generally obtained from a polyamic acid and a vinyl ether compound, but according to the results of studies by the inventors, the reaction is carried out in a solvent having an active hydrogen such as an amino group or a hydroxyl group, or an amino group. In the presence of a compound having an active hydrogen such as a hydroxyl group, the yield of obtaining a hemiacetal ester bond tended to be low. In addition, when using a solvent containing a nitrogen atom in a form other than a nitro group in the skeleton, the yield was low, so the case where the skeleton contains a solvent containing a nitrogen atom in a form other than a nitro group may also be included. It is not preferable.

In general, a polyimide having a low linear thermal expansion coefficient is often an aromatic polyimide, and an aromatic polyamic acid that is a precursor thereof is an amide solvent containing a nitrogen atom such as N-methylpyrrolidone or dimethylacetamide. Shows high solubility, but is often poorly soluble in solvents that do not contain nitrogen atoms, such as non-amide solvents. In particular, an aromatic polyamic that can realize low expansion, R ¹ is any structure represented by the above formula (3), and R ² is any structure represented by the above formula (5) Acids are not completely soluble in non-amide solvents such as lactones and sulfoxides. Here, the term “not completely dissolved” means that the polyamic acid cannot be completely dissolved at a concentration required for the reaction or coating formation, for example, 16.5% by weight in a solvent at 23 ° C.

However, the polyimide precursor having a hemiacetal ester bond used in the present invention is improved in solubility due to the carboxyl group being converted into a hemiacetal ester, and is not compared with a solvent not containing a nitrogen atom such as a non-amide solvent. Even high solubility.
Therefore, when the reaction between the polyamic acid and the vinyl ether compound is performed in a solvent that does not contain a nitrogen atom, the reaction efficiency is improved. In that case, a polyimide having a low linear expansion coefficient is achieved at the beginning as described above. In many cases, polyamic acid is not completely dissolved. However, in the present invention, the polyimide precursor was dissolved in the reaction solvent with the progress of the reaction of the polyamic acid, and finally dissolved completely, so the target product was obtained quantitatively.

  From the point that it is possible to prepare the polyimide precursor of the present invention in which the carboxyl group of polyamic acid has a 100% hemiacetal ester bond, the reaction solvent of polyamic acid and vinyl ether is a solvent that does not contain a nitrogen atom. Lactones and sulfoxides are preferably used. Examples of lactones include γ-butyrolactone, α-acetyl-γ-butyrolactone, ε-caprolactone, γ-hexanolactone, and δ-hexanolactone. Examples of sulfoxides include dimethyl sulfoxide, methyl ethyl sulfoxide, and diethyl. Examples thereof include sulfoxide. While dimethyl sulfoxide has high solubility, it is difficult to be oxidized and mutagenicity has been confirmed, and there are problems in stability and safety as a solvent. Therefore, lactones are particularly preferable.

Moreover, from the point which can prepare the polyimide precursor of this invention which made the carboxyl group of polyamic acid 100% a hemiacetal ester bond, as temperature at the time of reaction of polyamic acid and vinyl ether, 5-35 degreeC is 10-30 degreeC is more preferable. When the reaction temperature is higher than this, side reactions such as decomposition of the hemiacetal ester bond proceed, and thus there is a tendency that a polyimide precursor having a 100% hemiacetal ester bond cannot be obtained.
In addition, since the polyimide precursor used for this invention shows high solubility with respect to a low boiling point non-amide type solvent, operativity improves in processes, such as application | coating.

  The vinyl ether compound is appropriately selected and used according to the desired structure of the hemiacetal ester bond. For example, the primary vinyl ether compound for deriving A1 is specifically a linear or branched chain such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, n-butyl vinyl ether, n-amyl vinyl ether, octadecyl vinyl ether, etc. Vinyl ether compounds having a saturated or unsaturated hydrocarbon skeleton; vinyl ether compounds having an alicyclic saturated hydrocarbon skeleton such as cyclohexyl methyl vinyl ether, tricyclodecanyl methyl vinyl ether, pentacyclopentadecanyl methyl vinyl ether; ethylene glycol methyl vinyl ether , Ethylene glycol ethyl vinyl ether, ethylene glycol propyl vinyl ether, ethylene glycol butyl vinyl ether, polyethylene glycol Vinyl ether, polyethylene glycol ethyl vinyl ether, polyethylene glycol propyl vinyl ether, polyethylene glycol butyl vinyl ether, polyethylene glycol octyl vinyl ether, propylene glycol methyl vinyl ether, propylene glycol ethyl vinyl ether, propylene glycol propyl vinyl ether, propylene glycol butyl vinyl ether, polypropylene glycol methyl vinyl ether, polypropylene glycol Ethyl vinyl ether, polypropylene glycol propyl vinyl ether, polypropylene glycol butyl vinyl ether, polypropylene glycol octyl vinyl ether, butylene glycol methyl vinyl ether, butylene glycol ethyl Vinyl ether, butylene glycol propyl vinyl ether, butylene glycol butyl vinyl ether, polybutylene glycol methyl vinyl ether, polybutylene glycol ethyl vinyl ether, polybutylene glycol propyl vinyl ether, polybutylene glycol butyl vinyl ether, polybutylene glycol octyl vinyl ether, 2-vinyloxytetrahydropyran, etc. Examples thereof include vinyl ethers containing an ether bond in a linear, branched or alicyclic saturated or unsaturated hydrocarbon skeleton. Other examples include cyclic vinyl ether compounds such as 3,4-dihydro-2H-pyran.

  Specific examples of the secondary vinyl ether compound for deriving A2 include vinyl ethers having a linear or branched saturated or unsaturated hydrocarbon skeleton such as isopropyl vinyl ether, sec-butyl vinyl ether, sec-pentyl vinyl ether and the like. Compound: Vinyl ether compound containing an alicyclic saturated hydrocarbon skeleton such as cyclohexyl vinyl ether, tricyclodecanyl vinyl ether, pentacyclopentadecanyl vinyl ether; 1-methoxyethyl vinyl ether, 1-ethoxyethyl vinyl ether, 1-methyl-2- Examples thereof include vinyl ethers containing an ether bond in a linear or branched saturated or unsaturated hydrocarbon skeleton such as methoxyethyl vinyl ether and 1-methyl-2-ethoxyethyl vinyl ether.

Specific examples of the tertiary vinyl ether compound for deriving A3 include a vinyl ether compound having a linear or branched saturated or unsaturated hydrocarbon skeleton, such as tert-butyl vinyl ether and tert-amyl vinyl ether; Vinyl ether compounds containing an alicyclic saturated hydrocarbon skeleton such as 1-methylcyclohexyl vinyl ether and 1-adamantyl vinyl ether; linear or branched saturated or unsaturated carbonization such as 1,1-dimethyl-2-methoxyethyl vinyl ether Examples thereof include vinyl ethers containing an ether bond in the hydrogen skeleton.
Of the primary, secondary, and tertiary vinyl ether compounds, the number of repeating oxyalkylene residues in the case of including a polyoxyalkylene residue is 15 or less from the viewpoint of volatility after decomposition. preferable.

Moreover, if the polyimide precursor contained in the photosensitive resin composition of the present invention does not contain active hydrogen, a polymer repeating unit such as a polyimide precursor and / or a polybenzoxazole precursor and the above formula ( The repeating unit represented by 1) may be mixed. However, in order to form a good pattern, the repeating unit of the above formula (1) is preferably contained in at least 25 mol% or more, more preferably 50 mol% or more, and further 70 in the total repeating unit of the polyimide precursor. It is preferable to contain more than mol%, especially 90 mol% or more.
Examples of polyimide precursors that do not contain active hydrogen, polybenzoxazole precursors, and other polymer compounds include polyamic acid ester repeating units, polyamide phenol ester repeating units, polyamide phenol ether repeating units, polyphenylene ether, polyphenylene, Examples include polyester.

Moreover, in the polyimide precursor of this invention, it is preferable from the point of storage stability that the terminal of a polymer is end-capped with the structure or acid anhydride group which does not contain active hydrogen.
As a method of end-capping with a structure not containing an acid anhydride group or active hydrogen, for example, in the case of an amine-terminated polyimide precursor, a method of amidation with acetic anhydride, phthalic anhydride or a few -The method of making an terminal an amic acid with acid anhydrides, such as a naphthalic anhydride, etc. are mentioned.
If the terminal is an aromatic carboxylic acid, even if it has active hydrogen, it reacts with vinyl ether at room temperature to form a hemiacetal ester, and in this case, storage stability is not lowered.

When the polyimide precursor contained in the photosensitive resin composition of the present invention has a film thickness of 1 μm in order to increase the sensitivity of the photosensitive resin composition and obtain a pattern shape that accurately reproduces the mask pattern Furthermore, it is preferable to exhibit a transmittance of at least 5% with respect to any of the exposure wavelengths, and it is more preferable to exhibit a transmittance of 15% or more.
That the transmittance | permeability of a polyimide precursor is high with respect to exposure wavelength means that there is little loss of irradiation light, and a highly sensitive photosensitive resin composition can be obtained.
In addition, when exposure is performed using a high-pressure mercury lamp, which is a general exposure light source, a transmittance with respect to an electromagnetic wave having a wavelength of at least 436 nm, 405 nm, and 365 nm is formed on a film having a thickness of 1 μm. Is preferably 5% or more, more preferably 15%, and still more preferably 50% or more.

Either the weight average molecular weight or the number average molecular weight of the polyimide precursor is preferably in the range of 3,000 to 1,000,000, and in the range of 5,000 to 500,000, depending on the use. It is more preferable that it is in the range of 7,000 to 100,000. When either the weight average molecular weight or the number average molecular weight is less than 3,000, it is difficult to obtain sufficient strength when a coating film or film is formed. In addition, the strength of the film is reduced when heat treatment is performed to obtain polyimide. On the other hand, if either the weight average molecular weight or the number average molecular weight exceeds 1,000,000, the viscosity increases and the solubility decreases, so that a coating film or film having a smooth surface and a uniform film thickness is obtained. It's hard to be done.
The weight average molecular weight used here is a molecular weight obtained by a known method, exemplified by a value in terms of polystyrene by gel permeation chromatography (GPC), and the number average molecular weight is a terminal obtained from a ¹ H-NMR spectrum. Examples thereof include a method of determining from an integration ratio of a peak derived from a repeating unit of a part and a peak derived from a repeating unit of a non-terminal part.

In the photosensitive resin composition according to the present invention, the polyimide precursor may be blended with two or more kinds of polyimide precursors synthesized separately. Depending on the purpose, polyimide precursor synthesized using primary vinyl ether compound, polyimide precursor synthesized using secondary vinyl ether compound, polyimide precursor synthesized using tertiary vinyl ether compound May be used in combination as appropriate.
In the photosensitive resin composition according to the present invention, the solid content of the polyimide precursor is 0 in the entire photosensitive resin composition containing a solvent from the viewpoint of film physical properties of the pattern obtained, particularly film strength and heat resistance. It is preferably 1% by weight to 80% by weight, and more preferably 0.5% by weight to 50% by weight. When the solid content concentration is less than 0.1% by weight, the film thickness of the obtained coating film is thin, the followability with respect to the substrate having irregularities on the surface is lowered, and uneven coating tends to occur. On the other hand, when the solid content concentration is larger than 80% by weight, the viscosity increases and film thickness unevenness due to volatilization of the solvent during the coating tends to occur.
Moreover, in the photosensitive resin composition according to the present invention, the solid content of the polyimide precursor is described later with the solvent in the photosensitive resin composition from the viewpoint of film physical properties of the pattern obtained, particularly film strength and heat resistance. It is preferable to contain 30% by weight or more and 50% by weight or more based on the entire solid content excluding the vinyl ether compound.

  The photosensitive resin composition of this invention contains the compound which generate | occur | produces carboxylic acid by the effect | action of light as an essential component. As the compound that generates carboxylic acid by the action of light in the present invention, known compounds can be used without particular limitation as long as they generate carboxylic acid by being decomposed by absorbing electromagnetic waves. As the compound that generates carboxylic acid by the action of light used in the present invention, a compound that itself is decomposed by irradiation with electromagnetic waves or undergoes a reaction such as intramolecular transfer and changes from neutral to acidic is preferably used. . The compounds that generate carboxylic acid by the action of light may be used alone or in combination of two or more.

  As a compound that generates carboxylic acid by the action of light, it is preferable to use a compound having an o-quinonediazide group. A compound having an o-quinonediazide group has a large difference in hydrophobicity and hydrophilicity before and after exposure, and a large solubility contrast can be obtained. Further, since it has high sensitivity and a wide light absorption band, it can be applied to a wide range of light sources. Furthermore, various skeletons are commercially available and are easily available. When a polyimide precursor having a repeating unit represented by the formula (1) and a compound having an o-quinonediazide group are used in combination, a photosensitive resin composition having high sensitivity and low cost can be obtained.

  Examples of the compound having an o-quinonediazide group include o-benzoquinonediazide sulfonic acid ester or sulfonic acid amide, o-naphthoquinonediazide-4-sulfonic acid ester or sulfonic acid amide, or o-naphthoquinonediazide-5-sulfonic acid ester or Examples thereof include sulfonic acid amides. The compound having an o-quinonediazide group can be obtained, for example, by subjecting o-quinonediazidesulfonyl chlorides to a hydroxy compound, an amino compound or the like in the presence of a dehydrochlorinating agent.

  Examples of the o-quinonediazide sulfonyl chlorides include benzoquinone-1,2-diazide-4-sulfonyl chloride, naphthoquinone-1,2-diazide-5-sulfonyl chloride, and naphthoquinone-1,2-diazide-4-sulfonyl chloride. Can be used, but are not necessarily limited to those listed here.

  The compound to be reacted with the o-quinonediazide sulfonyl chloride is preferably a hydroxy compound from the viewpoint of photosensitive properties. Examples of the hydroxy compound include hydroquinone, resorcinol, pyrogallol, bisphenol A, bis (4-hydroxyphenyl) methane. 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 2,3,4-trihydroxybenzophenone, 2,3,4,4′-tetrahydroxybenzophenone, 2,2 ′, 4,4′-tetra Hydroxybenzophenone, 2,3,4,2 ′, 3′-pentahydroxybenzophenone, 2,3,4,3 ′, 4 ′, 5′-hexahydroxybenzophenone, bis (2,3,4-trihydroxyphenyl) Methane, bis (2,3,4-trihydroxyphenyl) pro 4b, 5,9b, 10-tetrahydro-1,3,6,8-tetrahydroxy-5,10-dimethylindeno [2,1-a] indene, tris (4-hydroxyphenyl) methane, tris ( 4-hydroxyphenyl) ethane and the like can be used. The hydroxy compounds used are not necessarily limited to those listed here.

  Examples of the amino compound include p-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenylsulfone, and 4,4′-. Diaminodiphenyl sulfide, o-aminophenol, m-aminophenol, p-aminophenol, 3,3′-diamino-4,4′-dihydroxybiphenyl, 4,4′-diamino-3,3′-dihydroxybiphenyl, bis (3-amino-4-hydroxyphenyl) propane, bis (4-amino-3-hydroxyphenyl) propane, bis (3-amino-4-hydroxyphenyl) sulfone, bis (4-amino-3-hydroxyphenyl) sulfone Bis (3-amino-4-hydroxyphenyl) hexafluo Propane, and bis (4-amino-3-hydroxyphenyl) hexafluoropropane can be used. The amino compounds used are not necessarily limited to those listed here.

  It is preferable from a viewpoint of a sensitivity that the compound which generate | occur | produces carboxylic acid by the effect | action of light is 0.005 weight%-20 weight% in the whole photosensitive resin composition containing a solvent. In the photosensitive resin composition according to the present invention, the compound that generates carboxylic acid by the action of light is 0.01% based on the total solid content excluding the solvent in the photosensitive resin composition and the vinyl ether compound described later. From the viewpoint of sensitivity, it is preferably contained in an amount of ˜45% by weight, and in the case of containing 0.1% by weight to 35% by weight, a decomposition product derived from a compound that generates carboxylic acid by the action of light after imidization is suppressed. Is more preferable. In particular, from the viewpoint of outgas generation, it is desired that the amount of the compound that generates carboxylic acid by the action of light is smaller.

The compound that generates carboxylic acid by the action of light used in the present invention preferably has absorption at at least one of electromagnetic waves having wavelengths of 436 nm, 405 nm, and 365 nm. The polyimide precursor contained in the photosensitive resin composition generally has strong absorption at a wavelength of 330 nm or less. Therefore, the compound that generates carboxylic acid by the action of light contained in the photosensitive resin composition preferably generates carboxylic acid by the action of light in a wavelength region in which the polyimide precursor easily passes, and is 330 nm or more. It is preferable to have absorption in the wavelength region. Furthermore, it has absorption in light of at least one wavelength among light having wavelengths of 436 nm, 405 nm, and 365 nm having high intensity among emission wavelengths of a high pressure mercury lamp that is a light source generally used for exposure. Among them, it is particularly preferable to have absorption at wavelengths of 436 nm and 405 nm.
Specifically, the compound that generates a carboxylic acid by the action of light used in the present invention preferably has a molar extinction coefficient of 1 or more at any wavelength of 365 nm or more, more preferably 10 or more. Preferably, it is 50 or more.

In addition, from the viewpoint of suppressing the remaining decomposition product derived from a compound that generates carboxylic acid by the action of light in the film after imidization, the thermal weight reduction of the compound itself that generates carboxylic acid at 400 ° C. in a nitrogen atmosphere The rate is preferably 50% or less, more preferably 30% or less, and even more preferably 10% or less.
In particular, when it is desired to suppress the residue of decomposition residues in the polyimide, the thermal weight reduction rate of the compound itself that generates carboxylic acid at 300 ° C. in a nitrogen atmosphere is preferably 50% or less, and 30% or less. More preferably, it is more preferably 10% or less.

The photosensitive resin composition of the present invention preferably does not contain active hydrogen, and preferably does not contain a compound containing active hydrogen. In particular, it is preferable not to contain water. When these are included, the hemiacetal ester bond is gradually decomposed and storage stability is lowered.
When a hemiacetal ester bond coexists with a compound having active hydrogen such as a hydroxyl group, an exchange reaction with them may occur. Since hemiacetal bonds are usually more stable than hemiacetal ester bonds, when the polyimide precursor and a hydroxyl group-containing compound coexist, the hemiacetal ester bonds are consumed by hydroxyl groups to produce polyamic acid. That is, the stability of the polyimide precursor is lowered when it coexists with a compound having active hydrogen such as a hydroxyl group. The rate of the decomposition reaction of the hemiacetal ester bond varies depending on its chemical structure, and the higher the rate of the reaction that forms the hemiacetal ester bond, the higher the decomposition rate.

  Further, from the viewpoint of improving storage stability, the water content in the photosensitive resin composition is preferably 1% by weight or less, and more preferably 0.1% by weight or less. Furthermore, it is most preferable that it does not contain water substantially. Here, “substantially free of water” means that the content of water in the composition is so small that a decrease in storage stability due to water is not observed. Specifically, it refers to a state where the moisture content in the composition is less than about 0.005% by weight, and further less than 0.001% by weight.

  Furthermore, hydrolysis of the hemiacetal ester bond proceeds catalytically in the presence of a sulfonic acid or a base. Therefore, storage stability can be improved by not containing a strongly acidic substance and a base substantially in the photosensitive resin composition. Here, “substantially free of strongly acidic substances and bases” means that the content of strongly acidic substances and bases in the composition is so small that no decrease in storage stability due to strongly acidic substances or bases is observed. Say. Specifically, it refers to a state in which the content of strongly acidic substances or bases in the composition is less than about 0.005% by weight, and further less than 0.001% by weight.

Various general-purpose solvents can be used as a solvent for dissolving, dispersing or diluting the photosensitive resin composition. These may be used alone or in admixture of two or more. However, in order to improve the storage stability of the photosensitive resin composition, it is preferable to use a solvent containing no active hydrogen. Furthermore, for the same purpose, a solvent that does not contain a nitrogen atom such as an amide bond in the skeleton is preferable. Moreover, it is preferable not to contain the solvent containing a nitrogen atom.
Moreover, you may use the solution obtained by the synthesis | combination reaction of the polyimide precursor as it is, and mix a photo-acid generator and another component as needed there.
The vinyl ether compound described below may be substituted for the solvent depending on the structure selected. In that case, a solvent for dissolving, dispersing or diluting the photosensitive resin composition may not be included.

Usable general-purpose solvents include, for example, ethers such as diethyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether; methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclopentanone Ketones such as cyclohexanone; ethyl acetate, butyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, acetate esters of the above glycol monoethers (for example, methyl cellosolve acetate, ethyl cellosolve) Acetate), methoxypropyl acetate, ethoxypropyl acetate, dimethyl oxalate, methyl lactate, ethyl lactate and the like; Halogenated hydrocarbons such as tylene, 1,1-dichloroethane, 1,2-dichloroethylene, 1-chloropropane, 1-chlorobutane, 1-chloropentane, chlorobenzene, bromobenzene, o-dichlorobenzene, m-dichlorobenzene; -Lactones such as butyrolactone; sulfoxides such as dimethyl sulfoxide, other organic polar solvents, and the like. Furthermore, aromatic hydrocarbons such as benzene, toluene, xylene, and other organic nonpolar solvents And so on. These solvents are used alone or in combination.
Among these, it is preferable to use lactones and sulfoxides from the viewpoint of excellent solubility and preparation of a high-concentration solution.

Moreover, it is preferable that the photosensitive resin composition of this invention contains a vinyl ether compound from the point which storage stability improves dramatically.
When the polyimide precursor is isolated, it is hydrolyzed by the action of moisture in the air over time during the storage process, and gradually returns to carboxylic acid. In particular, unlike an aliphatic hemiacetal ester bond composed of a relatively stable aliphatic carboxylic acid and a vinyl ether compound, an aromatic hemiacetal ester bond obtained from a reaction of an aromatic carboxylic acid and a vinyl ether compound, etc., only mixes the two. While the reaction proceeds at room temperature, when it is present alone, it often reacts with moisture in the air and is hydrolyzed.
However, the polyimide precursor having a hemiacetal ester bond is allowed to coexist with vinyl ether, whereby the carboxylic acid generated by hydrolysis is again converted to a hemiacetal ester. That is, like the polyimide precursor having a hemiacetal ester bond immediately after synthesis, a polyimide precursor in which substantially all of the carboxyl groups are hemiacetal esterified is obtained. Therefore, the storage stability as a resin composition becomes favorable by making the said polyimide precursor coexist with vinyl ether. In addition, in the case of a photosensitive resin composition containing a polyimide precursor having a plurality of protected sites, a plurality of protected sites may be present from the viewpoint of stabilizing the introduction rate of the protected sites. It is better to coexist a plurality of vinyl ether compounds used to prepare the compound.

  When a compound having active hydrogen such as water is mixed into the photosensitive resin composition from the air or the like, the polyimide precursor is decomposed into a polyamic acid. However, even in such a case, when coexisting with the vinyl ether compound, the polyamic acid reacts with the vinyl ether compound to regenerate the hemiacetal ester bond. Furthermore, in this case, the acetaldehyde generated simultaneously with the polyamic acid is also difficult to be oxidized and is not easily converted to acetic acid. Furthermore, since alcohol also becomes an acetal compound by exchange reaction with other hemiacetal ester bonds, as a result, the photosensitive resin composition does not contain active hydrogen.

Therefore, when an excessive amount of vinyl ether is contained with respect to the amount of the compound containing active hydrogen, the polyamic acid formed by the active hydrogen quickly becomes a hemiacetal ester bond. The characteristics of the photosensitive resin composition do not change.
By continuing this cycle, moisture mixed in the photosensitive resin composition is consumed from the air and the like, and the hemiacetal ester bond is regenerated, so that good solution stability is exhibited.

As content of a vinyl ether compound, it is preferable that it is 1 weight%-90 weight% in the whole photosensitive resin composition containing a solvent, and it is more preferable that it is 5 weight%-70 weight%. Moreover, when a vinyl ether compound contains a solvent, it is preferable from the point of the storage stability of a polyimide precursor that it is contained 55 parts weight or more with respect to 100 weight part of solvents. Depending on the selection of the vinyl ether compound, the vinyl ether compound may be substituted for the solvent and may not contain the solvent. Therefore, the content is appropriately selected depending on the type of the vinyl ether compound.
The greater the amount of the vinyl ether compound, the better the storage stability. On the other hand, when a polyimide precursor containing a large amount of aromatic skeleton is used, the solubility tends to decrease.
Therefore, from the viewpoint of improving the storage stability, it is preferable that the amount of the vinyl ether compound is as large as possible within a range in which a solid content in the photosensitive resin composition such as a polyimide precursor does not precipitate.

  The photosensitive resin composition according to the present invention may be a simple mixture of a polyimide precursor, a compound that generates carboxylic acid by the action of light, and, if necessary, a solvent. A photosensitive resin composition may be prepared by blending other components such as an agent.

Addition of a sensitizer may be effective when it is desired to improve the sensitivity by making it possible to sufficiently utilize the compound that generates carboxylic acid by the action of light using electromagnetic wave energy having a wavelength that passes through the polyimide precursor. .
In particular, when the absorption of the polyimide precursor is also at a wavelength of 360 nm or more, the effect of adding a sensitizer is great. Specific examples of compounds called sensitizers include thioxanthone and derivatives thereof such as diethylthioxanthone, coumarins and derivatives thereof, ketocoumarin and derivatives thereof, ketobiscoumarin and derivatives thereof, cyclopentanone and derivatives thereof , Cyclohexanone and derivatives thereof, thiopyrylium salts and derivatives thereof, thioxanthene series, xanthene series and derivatives thereof. However, it is preferable that these have no active hydrogen group from the viewpoint of the storage stability of the photosensitive resin composition.

Specific examples of coumarin, ketocoumarin and derivatives thereof include 3,3′-carbonylbiscoumarin, 3,3′-carbonylbis (5,7-dimethoxycoumarin), 3,3′-carbonylbis (7-acetoxycoumarin). ) And the like.
Specific examples of thioxanthone and derivatives thereof include diethyl thioxanthone and isopropyl thioxanthone.

Furthermore, benzophenone, acetophenone, phenanthrene, 2-nitrofluorene, 5-nitroacenaphthene, benzoquinone, 2-ethylanthraquinone, 2-tertiarybutylanthraquinone, 1,2-benzanthraquinone, 1,2-naphthoquinone, etc. Is mentioned.
These are sensitizers that exhibit an optimal sensitizing action depending on the structure of the compound that generates carboxylic acid by the action of light, in order to exhibit a particularly excellent effect when combined with the compound that generates carboxylic acid by the action of light. Is appropriately selected.

  In addition, in order to impart processing characteristics and various functionalities to the photosensitive resin composition according to the present invention as long as the objects and effects of the present invention are not hindered, various other organic or inorganic low molecules or polymers are also provided. You may mix | blend a compound. For example, dyes, surfactants, leveling agents, plasticizers, fine particles and the like can be used. The fine particles include organic fine particles such as polystyrene and polytetrafluoroethylene, inorganic fine particles such as colloidal silica, carbon, and layered silicate, and these may have a porous or hollow structure. The function or form includes pigments, fillers, fibers, and the like.

  The blending ratio of other optional components is appropriately selected depending on the properties of the optional components and is not particularly limited, but is 0.1% by weight to 30% based on the total solid content excluding the solvent of the photosensitive resin composition and the vinyl ether compound described later. A range of% by weight is preferred. If it is less than 0.1% by weight, the effect of adding the additive is difficult to be exhibited, and if it exceeds 30% by weight, the properties of the finally obtained cured resin are hardly reflected in the final product.

  The photosensitive resin composition according to the present invention can be used in various coating processes and molding processes to produce a film (film) or a three-dimensional shaped molded body.

  The polyimide obtained from the photosensitive resin composition of the present invention is excellent in the detachability of the hemiacetal esterification site, which is a solubility control component of the precursor in a basic solution. In addition, decomposition products (vinyl ether, acetaldehyde, alcohol) generated by thermal decomposition of the hemiacetal esterification site are often liquid at room temperature having a boiling point of 200 ° C. or less, and most of them are volatilized during the heating process. To do. Furthermore, it is presumed that almost all of the film is dissipated by heating at 250 ° C. or higher required for imidization. Therefore, the finally obtained polyimide film contains little decomposition residue derived from the solubility control component in the basic solution. Therefore, the original characteristics such as heat resistance, dimensional stability, and insulation of the polyimide are not impaired and are good.

For example, the 5% weight loss temperature measured in nitrogen of polyimide obtained from the photosensitive resin composition of the present invention is preferably 250 ° C. or higher, and more preferably 300 ° C. or higher. In particular, when used in applications such as electronic parts that pass through the solder reflow process, if the 5% weight loss temperature is 300 ° C. or less, defects such as bubbles occur due to the decomposition gas generated in the solder reflow process. There is a fear.
Here, the 5% weight reduction temperature is the time when the weight of the sample is reduced by 5% from the initial weight when the weight loss is measured using a thermogravimetric analyzer (in other words, the sample weight becomes 95% of the initial weight). Temperature). Similarly, the 10% weight reduction temperature is a temperature at which the sample weight is reduced by 10% from the initial weight.

It is preferable that the glass transition temperature of the polyimide obtained from the photosensitive resin composition of this invention is 260 degreeC or more from a heat resistant viewpoint. This is important for electronic members that have a solder reflow process. In applications where a thermoforming process is considered, such as an optical waveguide, it is preferable to exhibit a glass transition temperature of about 120 ° C. to 400 ° C., and more preferably a glass transition temperature of about 200 ° C. to 370 ° C.
Here, the glass transition temperature in the present invention is tan δ (tan δ = loss elastic modulus (E ″)) by dynamic viscoelasticity measurement when the polyimide obtained from the photosensitive resin composition can be formed into a film shape. / Storage elastic modulus (E ′)) is determined from the peak temperature. The dynamic viscoelasticity measurement can be performed, for example, with a viscoelasticity measuring apparatus Solid Analyzer RSA II (manufactured by Rheometric Scientific) at a frequency of 1 Hz and a temperature rising rate of 5 ° C./min. When the polyimide obtained from the photosensitive resin composition cannot be formed into a film shape, the determination is made based on the temperature at the inflection point of the baseline of the differential thermal analyzer (DSC).

From the viewpoint of dimensional stability, the polyimide obtained from the photosensitive resin composition of the present invention preferably has a linear thermal expansion coefficient of 60 ppm or less, and more preferably in the range of 0 ppm to 40 ppm. In the case of forming a film on a silicon wafer in a manufacturing process of a semiconductor element or the like, the range of 0 ppm to 25 ppm is more preferable from the viewpoint of adhesion and warpage of the substrate. Here, the linear thermal expansion coefficient in this invention can be calculated | required with the thermomechanical analyzer (TMA) of the film of the polyimide obtained from the photosensitive resin composition obtained by this invention. Using a thermomechanical analyzer (for example, Thermo Plus TMA8310 (manufactured by Rigaku Corporation), the heating rate is 10 ° C./min, and the tensile load is 1 g / 25000 μm ² so that the weight per cross-sectional area of the evaluation sample is the same. .

Similarly, from the viewpoint of dimensional stability, the polyimide obtained from the photosensitive resin composition of the present invention preferably has a humidity expansion coefficient of 40 ppm or less, and more preferably 20 ppm or less. Ideally, 10 ppm to 0 ppm is preferable.
Here, the humidity expansion coefficient in this invention can be calculated | required with the humidity variable mechanical analyzer (S-TMA) of the polyimide film obtained from the photosensitive resin composition obtained by this invention. With a variable humidity mechanical analyzer (for example, Thermo Plus TMA8310 modified (manufactured by Rigaku Corporation)), the temperature is kept constant at 25 ° C., and the humidity is 50% with the sample stabilized in an environment of 20% RH. The change in sample length when it is changed to Rh and becomes stable is divided by the change in humidity (in this case, 30 of 50-20), and the value divided by the sample length is the humidity expansion coefficient. . The tensile load is 1 g / 25000 μm ² so that the weight per cross-sectional area of the evaluation sample is the same.

Next, the pattern formation method using the photosensitive resin composition of this invention is demonstrated.
The pattern forming method of the present invention includes a heating step of heating during or after the formation of the film or molded body comprising the photosensitive resin composition according to the present invention, and a predetermined surface on the surface of the film or molded body after the heating step. An exposure step of irradiating an electromagnetic wave in a pattern, and a development step of developing using a basic solution as a developer.
The photosensitive resin composition containing the polyimide precursor and a compound that generates a carboxylic acid by the action of light is partially applied to the polyimide precursor by a heating step that is heated before or after the formation of the film or molded body. After breaking down the hemiacetal ester bond and imparting moderate solubility to the basic solution, the solubility of the exposed part in the basic solution is increased by the action of the carboxylic acid generated by the action of light in the exposure process. . By utilizing this change in solubility and exposing to a desired pattern, the pattern can be obtained by eluting the exposed portion with a basic solution.

The film | membrane or molded object which consists of the photosensitive resin composition concerning this invention can be formed by a well-known method. For example, the film can be obtained by applying the photosensitive resin composition of the present invention on a substrate and drying it. At this time, the substrate is an object on which a polyimide film is to be formed, and examples thereof include metals such as copper and stainless steel, inorganic materials such as silicon, metal oxides, and metal nitrides, and organic materials such as polyimide and polybenzoxazole. However, in the present invention, although the adhesiveness and the like slightly change depending on the substrate, the substrate is not particularly limited because the pattern formation and the characteristics of the obtained film are essentially not changed.
Examples of the application method include spin coating, die coating, and dip coating, but are not particularly limited, and known methods can be used. The pattern forming method of the present invention can be used for a film obtained by any coating method.
For drying, a known heating method such as a hot plate or an oven can be appropriately used.

In the heating step of heating at the time of formation of the film or molded body or after exposure after the formation, the heating temperature is such that the polyimide precursor partially decomposes the hemiacetal ester bond and has an appropriate solubility in a basic solution. Adjust appropriately so that it can be given. Depending on the heating conditions, the heating step can also serve as a drying step during the formation of the film or molded body. The heating temperature is preferably in the range of room temperature (23 ° C.) to 130 ° C. If the temperature exceeds 130 ° C., decomposition of a compound that generates a carboxylic acid by the action of light, such as an o-quinonediazide group, may start, and pattern formation becomes unstable. The heating temperature here depends on the structure of R ¹ in formula (1) of the polyimide precursor and A in formula (2). In general, when R ¹ has a strong electron-withdrawing property or A has a strong electron-donating property, decomposition of the hemiacetal ester bond proceeds at a lower temperature, and in the opposite case, heating at a higher temperature is often required. Tend. The heating temperature is appropriately selected depending on the structure of the polyimide precursor, and the heating time is 5 seconds to 120 minutes, preferably 30 seconds to 30 minutes from the viewpoint of productivity.
As the heating method, a known method can be appropriately used without particular limitation.

The heating conditions in the heating step of heating at the time of forming the film or the molded body or before the exposure after the formation can be determined by conducting the following preliminary experiment, for example.
First, for example, a 1 wt% heavy DMSO solution of a polyimide precursor is heated in an NMR tube, and the relationship between the heating conditions and the decomposition rate of the hemiacetal ester bond is determined by the integration ratio of the peaks of the NMR spectrum. It is applied to a substrate such as alkali-free glass, heated with a hot plate, and a sample with varying temperature and heating time is prepared. The sample is directly measured by IR, and from the integration ratio of the peak derived from vinyl ether by IR spectrum The relationship between the heating condition and the decomposition rate of the hemiacetal ester bond was obtained, or the above sample was dissolved in heavy DMSO, the NMR was measured, and the integral ratio of the spectrum determined the relationship between the heating condition and the decomposition rate of the hemiacetal ester bond. To find out.
From the relationship between the heating conditions obtained as described above and the decomposition rate of the hemiacetal ester bond, the range of the heating conditions is appropriately set narrow. The relationship of the dissolution rate with respect to the developing solution of the sample prepared under the same conditions as the heating conditions within the narrowly set range was determined, and the dissolution rate of the coating film of the polyimide precursor alone used in the developing solution was 0.1 nm / s to Heating conditions (heating temperature and heating so that the decomposition rate is in the range of 100 nm / s, preferably in the range of 0.5 nm / s to 50 nm / s, more preferably in the range of 1 nm / s to 20 nm / s. Time).
Alternatively, without obtaining the decomposition rate of the hemiacetal ester bond, a plurality of samples were prepared by changing the heating temperature and the heating time of the coating film of the polyimide precursor used, and the dissolution rate in the developer was 0.1 nm. The heating conditions may be found from a sample in the range of / s to 100 nm / s, preferably in the range of 0.5 nm / s to 50 nm / s, more preferably in the range of 1 nm / s to 20 nm / s.

In the exposure step, the film or molded body thus obtained is irradiated with electromagnetic waves in a pattern form directly or through a photomask on which a desired pattern is formed.
The exposure light source is not particularly limited, and any known light source may be used. However, in the case of a polyimide precursor, particularly an aromatic polyimide having a high heat resistance and a low linear thermal expansion coefficient, a wavelength of 350 nm or less is used. In order to use it as a highly sensitive photosensitive resin composition since it has strong absorption, it is preferable to expose with light having a wavelength of 360 nm or more. From the viewpoints of these conditions, availability, and maintenance costs, it is preferable to use a high-pressure mercury lamp or a similar light source.
The exposure method and exposure apparatus used in the exposure process are not particularly limited, and may be contact exposure or indirect exposure, and any known means such as a stepper, scanner, aligner, contact printer, laser, and electron beam drawing can be used. .

After the exposure, a development process is performed.
The photosensitive resin composition of this invention can change the solubility with respect to a basic solution in an exposure part and an unexposed part by the effect | action of the compound which generate | occur | produces carboxylic acid by the effect | action of light.

The unexposed part of the photosensitive resin composition of the present invention is hardly soluble in the basic solution, and the exposed part has increased solubility in the basic solution due to the action of the generated carboxylic acid. It becomes soluble.
That is, after exposure, a positive pattern can be obtained by developing with a basic solution.
Thus, the photosensitive resin composition of the present invention has an advantage that a cheaper alkaline aqueous solution can be used.

The developer used in the development step is not particularly limited, and a basic solution is applicable. Among these, a basic aqueous solution is preferable from the viewpoint of environmental suitability.
Although it does not specifically limit as basic aqueous solution, For example, the density | concentration is 0.01 weight%-30 weight%, Preferably, 0.05 weight%-10 weight% tetramethylammonium hydroxide (TMAH) aqueous solution, water Potassium oxide aqueous solution, sodium hydroxide aqueous solution, magnesium hydroxide aqueous solution, calcium hydroxide aqueous solution, sodium bicarbonate aqueous solution, other primary, secondary, tertiary amine aqueous solution, hydroxide ion and ammonium ion salt aqueous solution, etc. Is mentioned.
The solute may be one type or two or more types, and may contain 50% or more of the total weight, more preferably 70% or more, and an organic solvent or the like as long as water is contained.

  Although it does not specifically limit as an organic solvent, For example, ethers, such as diethyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether; Ethylene glycol monomethyl ether, ethylene glycol monoethyl Glycol monoethers such as ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether (so-called cellosolves); ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, cyclopentanone, cyclohexanone Ethyl acetate, acetic acid Chill, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, acetate esters of the glycol monoethers (for example, methyl cellosolve acetate, ethyl cellosolve acetate), methoxypropyl acetate, ethoxypropyl acetate, Esters such as dimethyl oxalate, methyl lactate, and ethyl lactate; alcohols such as methanol, ethanol, isopropanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, diethylene glycol, glycerin; methylene chloride, 1,1-dichloroethane, 1 , 2-dichloroethylene, 1-chloropropane, 1-chlorobutane, 1-chloropentane, chlorobenzene, bromobenzene, o-dichlorobenzene, m-dichlorobenzene Halogenated hydrocarbons of N, N-dimethylformamide, amides such as N, N-dimethylacetamide; pyrrolidones such as N-methylpyrrolidone; lactones such as γ-butyrolactone; sulfoxides such as dimethylsulfoxide, hexane, Examples include saturated hydrocarbons such as cyclohexane and heptane, other organic polar solvents, and aromatic hydrocarbons such as benzene, toluene, and xylene, and other organic nonpolar solvents. . These solvents are used alone or in combination. Further, in order to improve the pattern shape, these organic solvents and water, or basic or acidic aqueous solutions may be combined and used as a mixed solvent.

  From the viewpoint of the cost of the developer itself, waste liquid treatment, and the cost of production equipment, development with an aqueous alkaline solution is preferred. In particular, when high reliability is required for the finally obtained polyimide film, it is preferably an organic base rather than an alkali metal or alkaline earth metal hydroxide. In particular, tetramethylammonium hydroxide (TMAH) is preferable from the viewpoint of availability and cost.

The development can be performed by a known development method such as spray development, dip development, or paddle development. The temperature during development is preferably 1 ° C to 80 ° C, more preferably 4 ° C to 60 ° C.
After development, rinsing may be performed as necessary. The rinsing can be appropriately selected from water, a mixture of water and the above organic solvent, and a basic aqueous solution.

  If you want to further reduce residues in the coating film or improve the transparency of the coating film, the number of processes will increase, but after development and pattern formation, the whole will be exposed to generate carboxylic acid. From the above, it is possible to take a method of performing imidization described later. In particular, in the case where the compound that generates a carboxylic acid by the action of light is a compound having an o-quinonediazide group, it is highly effective because it is exposed to light and changed to a carboxylic acid to improve phototransparency and transparency.

Imidization is performed after the development step. Usually, imidization is often performed by heating with an oven or a hot plate.
In general, it is said that polyamic acid gradually undergoes imidization from about 150 ° C., and imidization is almost completed at a temperature of 200 ° C. or higher. However, when higher reliability is required, it is necessary to proceed with imidization more completely. In that case, it is ideal to heat the polyimide film finally obtained at a temperature equal to or higher than Tg. is there. However, in general, a polyimide film having sufficiently practical reliability can be obtained by heating at a temperature of 300 ° C. to 400 ° C.

  In the case of the photosensitive resin composition of the present invention, the hemiacetal ester bond is almost completely decomposed at about 180 ° C. Therefore, by increasing the heating time at a temperature of 180 ° C. or less, the component derived from the protective group More complete desorption can be promoted. The longer the heating time, the better from the viewpoint of reducing the residue in the polyimide. However, in order to balance the productivity, the heating is performed at a temperature in the range of 40 ° C. to 150 ° C. for 1 minute to 180 minutes in total. The heating is preferably performed for 5 minutes to 120 minutes.

Thereafter, in order to completely proceed with imidization, heating is performed in the range of 180 ° C. to 450 ° C., preferably 200 ° C. to 400 ° C. depending on the purpose. Preferably, the maximum heating temperature is 251 ° C. or higher and 400 ° C. or lower.
In particular, when a temperature of 100 ° C. or higher is applied, it is preferably performed in an inert atmosphere such as nitrogen or argon in order to prevent oxidation of the polyimide or the substrate. Furthermore, in order to reduce the residue in a polyimide, it is preferable to carry out under reduced pressure.

As described above, the photosensitive resin composition according to the present invention includes a polyimide precursor having a hemiacetal ester bond that can be easily synthesized with an inexpensive raw material. Indicates sensitivity. In addition, the polyimide precursor having a hemiacetal ester bond is finally decomposed by the high volatility of decomposition products other than polyamic acid generated by the decomposition of the hemiacetal ester bond and the decomposition of the hemiacetal ester bond. There is almost no residue in the resulting polyimide film. Furthermore, since hemiacetal esterification can be applied to various skeletons, there is a wide range of selection of the skeleton of the polyimide precursor to be used.
According to the present invention, since a pattern can be formed by adding a compound that generates carboxylic acid by the action of light, the photosensitive resin composition with high sensitivity can be obtained more easily.

Since the photosensitive resin composition according to the present invention can form a pattern by irradiating the surface of a film or a molded body made of the composition with an electromagnetic wave and selectively easily solubilizing the irradiated portion, the photosensitive resin composition can be used. It is possible to form a pattern for development without using a film made of the resin composition or a resist film for protecting the surface of the molded body from the developer. This method has an advantage that the pattern formation process is simple. In particular, when a basic aqueous solution is used, the adverse impact on the natural environment and occupational health is small.
Furthermore, it is possible to selectively control the decomposition rate of the hemiacetal ester bond by making two or more kinds of protected sites introduced by the hemiacetal ester bond have different decomposition temperatures, and it is more stable. Pattern formation is possible.

  The photosensitive resin composition according to the present invention is a known resin material such as printing ink, adhesive, filler, electronic material, optical circuit component, molding material, resist material, building material, three-dimensional modeling, and optical member. Can be used in all fields and products.

Since the photosensitive resin composition according to the present invention can select a polyimide precursor having a wide range of structures, the cured product obtained thereby has a characteristic that polyimide such as heat resistance, dimensional stability, and insulation characteristically has. Therefore, it is suitable as a film, a coating film or a three-dimensional structure for all known members to which polyimide is applied.
The photosensitive resin composition according to the present invention is used in a wide range of fields and products in which properties such as heat resistance, dimensional stability, and insulation are effective, such as paints or printing inks, color filters, and films for flexible displays. It is preferably used as a material for forming semiconductor devices, electronic parts, interlayer insulating films, wiring coating films, optical circuits, optical circuit parts, antireflection films, holograms, optical members, or building materials.

  In particular, a photosensitive resin composition containing a polyimide precursor is mainly used as a pattern forming material (resist), and the pattern formed thereby imparts heat resistance and insulation as a permanent film made of polyimide. For example, color filters, flexible display films, electronic components, semiconductor devices, interlayer insulating films, wiring coating films, optical circuits, optical circuit components, antireflection films, other optical members or electronic members are formed. Suitable for

  Further, in the present invention, a printed material, a color filter, a film for flexible display, a semiconductor device, an electronic component, an interlayer insulating film, which is at least partly formed by the photosensitive resin composition according to the present invention or a thermoset thereof, An article of any one of a wiring coating film, an optical circuit, an optical circuit component, an antireflection film, a hologram, an optical member, and a building material is provided.

(Production Example 1)
A 100 mL three-necked flask was heated in a nitrogen stream and sufficiently dried, then polymerized with a dimethylacetamide solvent, paying careful attention to moisture in the air, reprecipitated with acetone, and then dried BPDA- White solid of ODA (polyamic acid composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether) 1.98 g, 5 g of ethylene glycol butyl vinyl ether (EGBVE), dried 5 ml of gamma-butyrolactone was added. The mixture was stirred with a magnetic stirrer at room temperature under a dried nitrogen stream for 70 hours. Initially, BPDA-ODA did not dissolve, but dissolved with the progress of the reaction, resulting in a brown solution. Thereafter, a part of the reaction solution was re-precipitated with dried diethyl ether to obtain a white solid of BPDA-ODA protected ethylene glycol butyl vinyl ether (polyimide precursor 1). Analysis was performed by ¹ H-NMR, and the protection rate was determined from the integral value of the peak of hydrogen bonded to carbon between oxygen and oxygen in the vicinity of 6.2 ppm of the hemiacetal ester bond and the integral ratio of the hydrogen peak of the aromatic ring of diphenyl ether. It was confirmed that the reaction rate of the hemiacetal ester bond to the carboxyl group) was 100%. The weight average molecular weight in terms of polystyrene determined by GPC was 18,400.
The weight average molecular weight is a NPC-pyrrolidone (NMP) solution having a concentration of 0.5% by weight, and the developing solvent is a 10 mmol% LiBr-NMP solution having a water content of 500 ppm or less. (HLC-8120 used column TSK gels α-M; manufactured by Tosoh × 2) was measured under conditions of a solvent flow rate of 0.5 mL / min and 40 ° C. The weight average molecular weight was determined based on a polystyrene standard sample having the same concentration as the sample.

(Production Examples 2-3)
In the same procedure as in Production Example 1, using cyclohexyl vinyl ether (CVE: Production Example 2) or 2-vinyloxytetrahydropyran (THPVE: Production Example 3) instead of EGBVE as the vinyl ether compound, polyimide precursor 2, and The polyimide precursor 3 was obtained.

(Production Example 4)
A 100 mL three-necked flask was heated in a nitrogen stream and sufficiently dried, then polymerized with a dimethylacetamide solvent, paying careful attention to moisture in the air, reprecipitated with acetone, and then dried BPDA- White solid of ODA (polyamic acid consisting of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and 4,4′-diaminodiphenyl ether) 1.98 g, 2-vinyloxytetrahydropyran (THPVE) 5 g, 10 ml of dried γ-butyrolactone was added. The mixture was stirred with a magnetic stirrer for 44 hours at room temperature under a dry nitrogen stream. Initially, BPDA-ODA did not dissolve, but dissolved with the progress of the reaction, resulting in a brown solution. Thereafter, a part of the reaction solution was re-precipitated with dried diethyl ether to obtain a white solid of a BPDA-ODA vinyl ether partial protector. Analysis was performed by ¹ H-NMR, and the protection rate was determined from the integral value of the peak of hydrogen bonded to carbon between oxygen and oxygen in the vicinity of 6.2 ppm of the hemiacetal ester bond and the integral ratio of the hydrogen peak of the aromatic ring of diphenyl ether. It was confirmed that the reaction rate of the hemiacetal ester bond to the carboxyl group) was 55%. Therefore, 5 g of cyclohexyl vinyl ether was further added to the reaction solution, and the mixture was stirred at room temperature for 24 hours. A part of the reaction solution was reprecipitated with dried diethyl ether to obtain a white solid of polyimide precursor 4. When the protection rate and molecular weight were measured in the same procedure as in Production Example 1, the protection rate was 100% (CVE / THPVE = 35% / 65%), and the polystyrene-equivalent weight average molecular weight determined by GPC was 18600. .
Table 1 shows the reaction time, protection rate, and weight average molecular weight of the obtained polyimide precursors 1 to 4.

[Thermal degradation evaluation 1]
Using a 1 wt% deuterated dimethyl sulfoxide (DMSO) solution of polyimide precursors 1 to 4, heating at each temperature for 5 minutes in an NMR tube, measuring NMR, and measuring the protection rate from the integration ratio of the peaks in the spectrum . FIG. 1 shows the relationship between the heating temperature and the protection rate in a 1 wt% solution of polyimide precursors 1 to 4.

[Thermal degradation evaluation 2]
The reaction solution of the polyimide precursor 1 and the polyimide precursor 4 was apply | coated with the spin coat method on the chromium plating glass, and was heat-dried on the hotplate. Samples with various heating conditions were dissolved in heavy DMSO, and NMR was measured to determine the protection rate of each sample. As a result, as the heating temperature increased and as the time increased, deprotection progressed and the protection rate decreased. The relationship between the heating temperature and the protection rate in the coating film of the polyimide precursor 1 is shown in FIG. 2, and the relationship between the heating temperature and the protection rate in the coating film of the polyimide precursor 4 is shown in FIG.

[Dissolution rate evaluation]
2 and 3, the polyimide precursor 1 is heated at 110 ° C. for 20 minutes, and the polyimide precursor 4 is heated at 100 ° C. for 10 minutes, 2.38% by weight of the sample. The dissolution rate for tetramethylammonium hydroxide (TMAH) aqueous solution was determined. The results are shown in Table 2.

[Photosensitivity evaluation]
(1) Preparation of photosensitive resin composition (i) 20% by weight of o-quinonediazide photosensitizer (4NT-300 based on the solid content of polyimide precursor 1) in the reaction solution of polyimide precursor 1 of Production Example 1 (Ester of 2,3,4,4′-tetrahydroxybenzophenone and 6-diazo-5,6-dihydro-5-oxo-1-naphthalenesulfonic acid): manufactured by Toyo Gosei Kogyo Co., Ltd.) The photosensitive resin composition 1 was prepared by this.

  (Ii) 30% by weight of o-quinonediazide photosensitizer (DTRP-250 (2,3,4-trihydroxy) based on the solid content of the polyimide precursor 4 with respect to the reaction solution of the polyimide precursor 4 of Production Example 4 Ester of benzophenone and 6-diazo-5,6-dihydro-5-oxo-1-naphthalenesulfonic acid): manufactured by Daito Chemix Co., Ltd.) was added and stirred to prepare photosensitive resin composition 2.

(2) Pattern formation evaluation (i) The photosensitive resin composition 1 is formed on a chromium-plated glass by a spin coat method under the following conditions, and after exposure with various doses, development And then rinsed.
Initial film thickness: 4.0 μm
Drying: 110 ° C. for 20 minutes Development (dip): 2.38 wt% TMAH aqueous solution for 3 minutes (23 ° C.)
Rinse: H ₂ O 5 seconds (23 ° C.)

Was determined to create sensitivity sensitivity curve in this condition, shows the behavior of the positive type exposure unit is dissolved, the sensitivity was 110 mJ / cm ^2.
Exposure was performed using a manual exposure apparatus MA-1100 manufactured by Dainippon Screen, and light from a high-pressure mercury lamp was used without using a filter.
Next, exposure was performed through a photomask, and pattern formation was examined. A pattern having a good shape was obtained under the following conditions. Even after development, no pattern loss was observed. Furthermore, when imidization was performed by heating at 350 ° C. for 1 hour in a nitrogen atmosphere, the film thickness was 2.6 μm, but the pattern was not destroyed and the state before baking was maintained.

Initial film thickness: 4.0 μm
Drying: 110 ° C., 20 minutes Exposure: 500 mJ / cm ²
Development (dip): 2.38 wt% TMAH aqueous solution 5 minutes (23 ° C.)
Rinse: H ₂ O 5 seconds (23 ° C.)
Film thickness after development: 4.0 μm
The obtained pattern is shown in FIG.

(Ii) Pattern formation evaluation was performed using the photosensitive resin composition 2 in the same manner as the above evaluation.
Initial film thickness: 4.3 μm
Drying: 100 ° C. for 10 minutes Development (dip): 2.38 wt% TMAH aqueous solution for 5 minutes (23 ° C.)
Rinse: H ₂ O 20 seconds (23 ° C.)

When a sensitivity curve was created under these conditions and the sensitivity was determined, it showed a positive behavior in which the exposed area was dissolved, and the sensitivity was 400 mJ / cm ² .
Next, exposure was performed through a photomask, and pattern formation was examined. A pattern having a good shape was obtained under the following conditions. Even after development, no pattern loss was observed. Furthermore, when imidization was performed by heating at 350 ° C. for 1 hour in a nitrogen atmosphere, the film thickness was 2.5 μm, but the pattern was not destroyed and the state before baking was maintained.

Initial film thickness: 4.3 μm
Drying: 100 ° C., 10 minutes Exposure: 800 mJ / cm ²
Development (dip): 2.38 wt% TMAH aqueous solution 5 minutes (23 ° C.)
Rinse: H ₂ O 20 seconds (23 ° C.)
Film thickness after development: 4.2 μm
The obtained pattern is shown in FIG.

  From these results, in the photosensitive resin composition of the present invention, the polyimide precursor used can control the decomposition rate of the hemiacetal ester bond depending on the heating conditions. It can be controlled stably. Therefore, it turned out that a favorable pattern can be formed by combining with the compound which generate | occur | produces carboxylic acid by the effect | action of light like an o-quinonediazide compound.

It is the figure shown about the relationship between the heating temperature and the protection rate in the 1 weight% concentration solution of the polyimide precursors 1-4. It is the figure shown about the relationship between the heating temperature in the coating film of the polyimide precursor 1, and a protection factor. It is the figure shown about the relationship between the heating temperature in a coating film of the polyimide precursor 4, and a protection factor. 2 is a photograph showing a pattern obtained using the photosensitive resin composition 1. FIG. 3 is a photograph showing a pattern obtained using the photosensitive resin composition 2. FIG.

Claims (20)

A polyimide precursor having a repeating unit represented by the following formula (1), a compound that generates a carboxylic acid by the action of light , one or more vinyl ether compounds, and a solvent, and the vinyl ether with respect to 100 parts by weight of the solvent A photosensitive resin composition containing 55 parts by weight or more of a compound .
(In Formula (1), R ¹ is a tetravalent organic group, R ² is a divalent organic group, and R ¹ and R ² that are repeated may be the same or different. R ³ and R ⁴ are each independently a monovalent organic group having the structure of the following formula (2), and they may be the same or different, and repeated R ³ and R ⁴ are Each may be the same or different.)
(In Formula (2), R ⁵ , R ⁶ , and R ⁷ are each independently hydrogen, a halogen atom, or a monovalent organic group, A is a monovalent organic group, and repeated A's are the same. R ⁵ , R ⁶ , R ⁷ , and A may be bonded to each other to represent a cyclic structure.   The photosensitive resin composition containing the compound which generate | occur | produces the carboxylic acid by the effect | action of light and the polyimide precursor which has a repeating unit represented by following formula (1).

(In formula (1), R ¹ Is a tetravalent organic group, R ² Is a divalent organic group and is repeated R ¹ And R ² Each may be the same or different. R ³ And R ⁴ Are each independently a monovalent organic group having the structure of the following formula (2), which may be the same or different, and are repeated R ³ And R ⁴ Each may be the same or different. )
(In formula (2), R ⁵ , R ⁶ , R ⁷ Are each independently hydrogen, a halogen atom, or a monovalent organic group, A is a monovalent organic group, and at least one of A is a monovalent organic group having 1 to 30 carbon atoms containing an ether bond. It is a group. The repeated A's may be the same or different. R ⁵ , R ⁶ , R ⁷ , And A may be bonded to each other to indicate a cyclic structure. )   The photosensitive resin composition of Claim 2 containing 1 or more types of vinyl ether compounds.   The photosensitive resin composition according to claim 3, further comprising a solvent, wherein 55 parts by weight or more of the vinyl ether compound is contained with respect to 100 parts by weight of the solvent. The photosensitive resin composition according to any one of claims 1 to 4, wherein the compound that generates carboxylic acid by the action of light is a compound having an o-quinonediazide group. In the polyimide precursor, the formula (2) at least one A in is a monovalent organic group having 1 to 30 carbon atoms containing no active hydrogen, according to any one of claims 1 to 5 Photosensitive resin composition. The photosensitive resin composition in any one of Claims 1 thru | or 6 in which A in said Formula (2) contains 2 or more types of organic group in the said polyimide precursor. In the polyimide precursor, the organic group group in which the carbon atom bonded to the oxygen atom in A in the formula (2) is a primary carbon atom is A1, and the organic group group is a secondary carbon atom. A2, when the organic group of tertiary carbon atoms is A3, A is A1 and A2, A1 and A3, A2 and A3, or A1 and A2 and A3, each of which is a combination of two or more The photosensitive resin composition in any one of Claims 1 thru | or 7 containing the above organic group. In the polyimide ^{precursor, R 5, R 6, R} 7 in the formula (2) is hydrogen, the photosensitive resin composition according to any one of claims 1 to 8. The photosensitive resin composition in any one of Claim 1 thru | or 9 which does not contain an acidic substance and an amine substantially. Compound that generates a carboxylic acid by the action of the light, 436 nm, 405 nm, the photosensitive according to any one of claims 1 to 10, characterized by having an absorption in at least one wavelength of the electromagnetic wave of a wavelength of 365nm Resin composition. The photosensitive resin composition according to any one of claims 1 to 11, characterized in that it comprises a sensitizing dye which does not contain active hydrogen. In the polyimide precursor, R ¹ and / or R ² in the formula (1), the photosensitive resin composition according to any one of claims 1 to 12, characterized in that an aromatic ring. In the polyimide precursor, the formula (1) R ¹ in is a backbone derived from an aromatic tetracarboxylic dianhydride, the photosensitive resin composition according to any one of claims 1 to 13. In the said polyimide precursor, 33 mol% or more among R < ¹ > in said Formula (1) is the structure in any one represented by following formula (3), The photosensitive in any one of Claims 1 thru | or 14 Resin composition.
In the said polyimide precursor, 33 mol% or more among R < ² > in said Formula (1) is the structure in any one represented by following formula (4), The photosensitive in any one of Claims 1 thru | or 15 Resin composition.
(R ¹⁴ is a divalent organic group, an oxygen atom, a sulfur atom, or a sulfone group, and R ¹⁵ and R ¹⁶ are a monovalent organic group or a halogen atom.) The photosensitive resin composition in any one of Claims 1 thru | or 16 containing the solvent which does not contain a nitrogen atom.   A heating step of heating at or after the formation of the film or molded body made of the photosensitive resin composition according to any one of claims 1 to 17, and a predetermined surface on the surface of the film or the molded body after the heating step. A pattern forming method comprising an exposure step of irradiating electromagnetic waves in a pattern and a development step of developing using a basic solution as a developer. The pattern formation method according to claim 18 , wherein the development step is performed using a basic aqueous solution and is a positive type. Wherein after the development step, and a step of heating the film or molded product, the maximum temperature of the heating temperature is 400 ° C. or less 251 ° C. or higher, a pattern forming method according to claim 18 or 19.