JP5117281B2 - Photosensitive heat resistant resin composition - Google Patents

Description

  The present invention relates to a photosensitive resin composition, and also relates to a semiconductor device having a relief pattern obtained by a process of exposure / post-exposure heating / development.

There are significant advances in miniaturization and high performance of semiconductor devices, but the technology required to fully exhibit the performance is package technology. For example, many logic semiconductors having a very large number of extraction electrodes and driven at a high operating frequency are processed into a package form called a flip chip in which electrodes called bumps are directly formed on the surface of the semiconductor chip. In that case, since the arrangement of the electrodes in the chip and the arrangement of the electrodes for connecting to the printed wiring board are often different, the wiring is redrawn. This is called rewiring, but it is necessary to form an insulating film between the upper and lower wirings (interlayer).
Another example of a high-performance package is a ball grid array (BGA) or a chip size package (CSP). In this case, a semiconductor chip is mounted on a substrate called a package substrate in which very fine wirings are multilayered, and solder balls are mounted on the back surface of the substrate to form a package. An interlayer insulating film is also used for this package substrate.

Further, in recent years, a stacked high-density package called a multichip package (MCP) or a stacked CSP has been widely used. Here, a plurality of chips are stacked using an adhesive film called a die attach film (DAF), and the electrode pads arranged around each chip and the package substrate are connected by a wire bond method. In some memories, the electrode pads are arranged in the center of the chip. In this case, rewiring is performed and pads are formed in order to wire bond around the chip to create an MCP. Again, the upper and lower wiring layers are isolated using an interlayer insulating film.
In many cases, a surface protective film called a buffer coat is formed on the surface of the semiconductor chip to protect the chip.

  In the next-generation applications of interlayer insulating films and surface protective films constituting these packages, many characteristics described below are required. First, heat resistance is required to withstand the solder reflow process when the package is mounted on a printed wiring board. The second requirement is mechanical properties. The package is made by combining various materials, and the thermal expansion coefficient of each material is different. When resin sealing is performed, high heat is applied, and stress derived from the difference in coefficient of thermal expansion occurs in the process of cooling. The finished package imposes severe tests called heat shock tests or heat cycle tests. This means that thermal stress is generated inside the package by repeatedly changing the temperature of the package, and reliability is assured by confirming that the semiconductor and the package can withstand it. In order to withstand this test, the insulating film and the surface protective film are required to have sufficient mechanical properties. Third, in order to efficiently transmit a high-speed signal, it is desirable that the dielectric constant and dielectric loss tangent (tan δ) of the insulating film be small. The fourth requirement is to have photosensitivity. In the interlayer insulating film, it is necessary to form a via which is a connecting portion in the vertical direction. However, the processing size becomes finer and it is desirable to form by a photolithography method. Photosensitive polyimide and photosensitive polybenzoxazole are widely used as materials that satisfy these requirements (Non-patent Documents 1 and 2).

  In addition, photosensitive polyimide and photosensitive polybenzoxazole are converted into heat-resistant polymers by thermosetting at a temperature of around 350 ° C after fine processing. In recent years, it is necessary to lower the heat treatment temperature. Has arisen. As the background, when a device such as a nonvolatile memory is heat-treated at a high temperature, the semiconductor itself may malfunction. In addition, in MCP, a semiconductor wafer is thinned to 100 μm or less due to package thickness restrictions. At this time, if the heat treatment temperature of the buffer coat is high, the wafer warp due to thermal stress becomes large and cannot be handled. There is also. Therefore, fifthly, it is desirable that the heat treatment can be completed at a low temperature.

  In order to solve these problems, some examples have already been proposed regarding the photosensitive composition comprising a combination of a polymer, a crosslinking agent and a photoacid generator. For example, Patent Document 1 discloses a photosensitive polyimide obtained by adding a crosslinking agent and a photoacid generator to a soluble polyimide having a phenolic hydroxyl group as a side chain substituent. Patent Document 2 discloses a photocrosslinking agent for a polyimide comprising a copolymer of diaminopolysiloxane and a carboxyl group-containing diamine and a dicarboxylic acid anhydride having a 2,5-dioxotetrahydrofuryl group as one acid anhydride group. And a photosensitive composition in which a photoacid generator is mixed. In Patent Document 3, a negative photosensitive composition comprising a soluble polyimide having a specific structure, a crosslinking agent capable of reacting with the polyimide under an acid catalyst, and a photosensitizer that decomposes with actinic rays to generate an acid and a sensitizer. Is disclosed.

However, photosensitive polyimide and photosensitive polybenzoxazole are formed by image-forming a negative photosensitive composition comprising a mixture of a polyimide or polybenzoxazole precursor polymer and a photosensitive component using photolithography, followed by heat treatment. The principle is to convert to a stable heat-resistant structure, and sometimes there is a trade-off relationship between the final physical properties and the requirements for image formation such as photosensitivity and resolution. In addition, mechanical properties and dielectric constant may be insufficient for next-generation applications. Furthermore, there is also a problem that if the thermosetting temperature is lowered, the original physical properties of the heat resistant resin cannot be exhibited sufficiently. Certainly, the polyimide resin itself is an engineering plastic having the highest heat resistance. However, since it is insoluble in many solvents, it does not become a base polymer for a photosensitive composition. Furthermore, the structure is soluble in a solvent at the expense of some of the original characteristics of polyimide.
Further, Patent Document 4 can be cited as one using polyethersulfone as the photosensitive resin. Patent Document 4 discloses a composition in which polyethersulfone is added to an epoxy resin in the range of 3 to 50%, and a photoacid generator and an organic filler are added. Here, the photoacid generator cures the epoxy resin by exposure, and polyethersulfone is only added as an auxiliary agent.

Japanese Patent Laid-Open No. 10-316751 JP 2000-034347 A JP 2003-207892 A Japanese Patent Laid-Open No. 11-143073 Mitsue Ueda, “Photosensitive Polyimide”, Journal of the Japan Society of Photography, Japan Society of Photography, 2003, 06, 4, p367-375 Akihiko Ikeda, Akiyoshi Mizuno, "Photosensitive resin learned from the beginning", Industrial Research Committee, April 10, 2002, p125-142

  An object of this invention is to provide the photosensitive resin composition excellent in photosensitivity, such as developability, a sensitivity, and the resolution, and the relief pattern which is excellent in heat resistance, ie, has a high glass transition temperature.

As a result of intensive studies based on these backgrounds, the present inventors have only added additives to polyethersulfone, which is a heat-resistant engineering plastic, without particularly introducing a crosslinking group or reactive group into the resin itself. Exposure to actinic light and further heating to induce a crosslinking reaction, followed by development has provided a photosensitive resin composition capable of forming a heat-resistant thin film pattern.
Here, it is not a method of converting to a heat-resistant polymer structure by heating after image formation, but because engineering plastics with excellent heat resistance and mechanical properties are used as the resin, the physical properties of the insulating film can be freely selected by selecting the polymer to be used It has the advantage that it can be designed. Since it is based on polyethersulfone having excellent electrical characteristics, an image-formed insulating film for a device can be obtained.

That is, the present invention is as follows.
1. (A) With respect to 100 parts by mass of polyethersulfone represented by the following general formula (I), (B) a CH ₂ OR group that causes a crosslinking reaction in the presence of an acid catalyst (where R is a carbon number of 1 to 4). A photosensitive resin composition comprising 2 to 40 parts by mass of a crosslinking agent having 2 to 20 parts by mass of a photoacid generator having a naphthalene nucleus or an anthracene nucleus.
(In the formula, m is 0 or 1, n is an integer of 10 to 400, and Ar is an aromatic group having 6 to 18 carbon atoms.)

2. 2. The photosensitive resin composition as described in 1 above, wherein (A) the polyethersulfone is represented by formula (I) wherein m is 1 and Ar is a biphenyl group.
3. _3. The photosensitive resin composition as described in 1 or 2 above, wherein the crosslinking agent (B) has a CH ₂ OCH ₃ group that causes a crosslinking reaction in the presence of an acid catalyst.
4). (1) A photosensitive resin layer comprising the photosensitive resin composition according to any one of the above 1 to 3 is formed on a substrate, (2) exposed with actinic rays, and (3) at 80 to 190 ° C. A method for producing a cured relief pattern, characterized by heating and (4) developing.
5. A semiconductor device having a relief pattern obtained by the manufacturing method described in 4 above.

  The photosensitive resin composition of this invention has the effect excellent in photosensitivity, such as developability, a sensitivity, and the resolution. Moreover, the relief pattern of the present invention exhibits an effect excellent in heat resistance.

Each component which comprises the photosensitive resin composition of this invention is demonstrated concretely below.
(A) Polyethersulfone As the polyethersulfone, those represented by the following general formula (I) are preferable because the electric characteristics and heat resistance of the formed image pattern are good.
(In the formula, m is 0 or 1, n is an integer of 10 to 400, and Ar is an aromatic group having 6 to 18 carbon atoms.)

Furthermore, n is preferably an integer of 20 to 200. Ar preferably has the following structure.

Preferred polysulfones are those whose repeating units are represented by the following general formulas (II) and (III), and those represented by the following general formula (III) are most preferred. This is also referred to as PEES below.

Polyethersulfone can be synthesized by a known method as disclosed in “Engineering Polymer”, Chemical Industry Daily, p268 of 1996.

(B) Crosslinking agent having a CH ₂ OR group that causes a crosslinking reaction in the presence of an acid catalyst (B) The crosslinking agent is a compound having a CH ₂ OR group that causes a crosslinking reaction in the presence of an acid catalyst. (B) The crosslinking agent is preferably at least one compound selected from the group consisting of the following compounds.

A compound having a benzene nucleus represented by the following general formula:
(In the formula, R is an alkyl group having 1 to 4 carbon atoms.)

A compound having a naphthalene nucleus represented by the following general formula:
(In the formula, R is an alkyl group having 1 to 4 carbon atoms.)

A compound having an anthracene nucleus represented by the following general formula:
(In the formula, R is an alkyl group having 1 to 4 carbon atoms.)

A compound having a diphenyl nucleus represented by the following general formula:
(In the formula, R is an alkyl group having 1 to 4 carbon atoms.)

A compound having a diphenylmethylene nucleus represented by the following general formula:
(In the formula, R is an alkyl group having 1 to 4 carbon atoms.)

A compound having a diphenyl ether nucleus represented by the following general formula:
(In the formula, R is an alkyl group having 1 to 4 carbon atoms.)

A compound having a triazine nucleus represented by the following general formula is preferred.

(In the formula, R is an alkyl group having 1 to 4 carbon atoms.)

Among the crosslinking agents, those in which R is a methyl group are preferable.
Among them, a crosslinking agent in which CH ₂ OR described by the following chemical formula is substituted in one compound in four groups is preferable.
Among these, 4,4′-methylenebis [2,6-bis (methoxymethyl) phenol] (hereinafter also referred to as MBMP) is particularly preferable.

Here, the amount of the crosslinking agent having a CH ₂ OR group that causes a crosslinking reaction in the presence of an acid catalyst is preferably 2 to 40 parts by mass, more preferably 4 to 100 parts by mass with respect to 100 parts by mass of (A) polyethersulfone. 30 parts by mass. When the amount of the crosslinking agent having a CH ₂ OR group causing a crosslinking reaction in the presence of an acid catalyst is 2 parts by mass or more with respect to 100 parts by mass of the polyethersulfone (A), the image forming property is good, and 40 parts by mass. The characteristics of the film obtained by the heat treatment are good when it is below.

(C) Photoacid generator having a naphthalene nucleus or anthracene nucleus (C) As a photoacid generator, an acid is generated by irradiation with actinic rays such as ultraviolet rays, and heat resistance after heat treatment is particularly required. Therefore, those having a naphthalene nucleus or an anthracene nucleus are used. Examples of the photoacid generator having a naphthalene nucleus include compounds represented by the following formula.

Examples of the photoacid generator having an anthracene nucleus include the following compounds.

  (C) As for the quantity of a photo-acid generator, 2-20 mass parts is preferable with respect to 100 mass parts of (A) polyether sulfone, More preferably, it is 3-16 mass parts. Here, when the amount of the photoacid generator having a naphthalene nucleus or an anthracene nucleus is 2 parts by mass or more with respect to 100 parts by mass of (A) polyethersulfone, the photosensitivity is good, and when it is 20 parts by mass or less, thermosetting is performed. The physical properties of the film after being good.

(D) Solvent
It is preferable to add the solvent (D) to the photosensitive resin composition to form a varnish and use it as a photosensitive resin composition solution. An organic solvent is used as the solvent. Specifically, aprotic polar solvents such as dimethyl sulfoxide, N, N-dimethylformamide (hereinafter also referred to as DMF), dimethylacetamide (hereinafter also referred to as DMAc) N-methylpyrrolidone, nitrobenzene, dichloromethane, tetrachloroethane, chloroform, etc. And ketones such as cyclopentanone and cyclohexanone.
(D) As for the addition amount in the case of adding a solvent, 100-4000 mass parts is preferable with respect to 100 mass parts of (A) polyethersulfone, More preferably, it is 200-2000 mass parts. When the amount of the solvent added is 100 parts by mass or more, the solubility is good, and when it is 4000 parts by mass or less, the film forming property including the thick film is good.

(E) Other components The following various compounds can be added to the photosensitive resin composition as needed.
A sensitizer can be added to improve sensitivity. Examples of the sensitizer include the following. As for the addition amount of a sensitizer, 0.1-10 mass parts is recommended with respect to 100 mass parts of (A) polyethersulfone.

Examples of the surfactant include polypropylene glycol, polyglycols such as polyoxyethylene lauryl ether, and nonionic surfactants composed of derivatives thereof. Fluorosurfactants such as Fluorard (registered trademark) (manufactured by Sumitomo 3M), MegaFac (registered trademark) (manufactured by Dainippon Ink & Chemicals, Inc.), or Lumiflon (registered trademark) (manufactured by Asahi Glass Co., Ltd.) Furthermore, organic siloxane surfactants such as KP341 (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name), DBE (manufactured by Chisso Corporation: trade name), or granol (manufactured by Kyoeisha Chemical Co., Ltd .: trade name) are listed. By adding the surfactant, it is possible to make it more difficult for the non-uniform coating phenomenon of the coating film on the wafer edge during coating to occur.
The addition amount when adding the surfactant is preferably 0 to 10 parts by mass and more preferably 0.01 to 1 part by mass with respect to 100 parts by mass of the (A) polyethersulfone. If the addition amount is within 10 parts by mass, the heat resistance of the film after thermosetting is good.
Adhesion aids include alkyl imidazolines, butyric acid, alkyl acids, polyhydroxystyrene, polyvinyl methyl ether, t-butyl novolac, epoxy polymers, and silane coupling agents.

Specific preferred examples of the silane coupling agent include 3-methacryloxypropyltrialkoxysilane, 3-methacryloxypropyl dialkoxyalkylsilane, 3-glycidoxypropyltrialkoxysilane, 3-glycidoxypropyl dialkoxy. Reaction of alkylsilane, 3-aminopropyltrialkoxysilane or 3-aminopropyl dialkoxyalkylsilane with acid anhydride or acid dianhydride, 3-aminopropyltrialkoxysilane or 3-aminopropyl dialkoxyalkylsilane The thing which converted the amino group into the urethane group and the urea group is mentioned. In this case, the alkyl group includes a methyl group, an ethyl group, a butyl group, the acid anhydride includes maleic anhydride, phthalic anhydride, the acid dianhydride includes pyromellitic dianhydride, 3, 3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, etc., urethane group is t-butoxycarbonylamino group, urea group is phenylaminocarbonylamino Group and the like.
The addition amount in the case of adding an adhesion assistant is preferably 0 to 30 parts by mass and more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of (A) polyethersulfone. If the addition amount is 30 parts by mass or less, the heat resistance of the film after thermosetting is good.

<Relief pattern and semiconductor device manufacturing method>
Next, a method for manufacturing a relief pattern will be specifically described below.
(1) A step of forming a photosensitive resin layer made of a photosensitive resin composition on a substrate (first step).
The above photosensitive resin composition solution is finally applied to a substrate such as a silicon wafer, a ceramic substrate, or an aluminum substrate by spin coating using a spin coater, or a coater such as a die coater, bar coater, wire coater, or roll coater. It apply | coats so that the film thickness of a cured film may be set to 0.1-20 micrometers, and it is set as the photosensitive resin layer. Or it is also possible to apply | coat to a predetermined place using an inkjet nozzle or a dispenser. This is dried at 50 to 140 ° C. using an oven or a hot plate to remove the solvent. This is called pre-baking.

(2) A step of exposing with actinic rays (second step).
Subsequently, the photosensitive resin layer is exposed with actinic rays through a mask. Specifically, exposure with actinic radiation is performed using a contact aligner or a stepper, or light, electron beam, or ion beam is directly irradiated. As the actinic ray, g-line, h-line, i-line, or KrF laser can also be used.

(3) A step of heating at 80 to 190 ° C. (third step).
In the third heating step, for example, a hot plate, infrared rays, electromagnetic induction, or the like can be used as a heating means. However, from the accuracy of temperature and time control applied, the pot plate has a temperature of 80 to 190 ° C. for 1 to 20 minutes. It is recommended to heat.
This third step is called PEB (Post Exposure Bake), and finally a good pattern can be formed by selecting conditions. In order to obtain a good pattern, it is essential to make a difference in the dissolution rate of the exposed area and the unexposed area in the developer.
A method for finding the conditions for realizing this will be described. After the film of the photosensitive composition is formed on the wafer according to the first step, a scratch reaching the wafer surface is made. Next, a half of the wafer is covered with a light shielding sheet so that a part of the scratch is hidden. Next, this sheet is regarded as a mask and exposure is performed according to the second step. Next, PEB is performed for a certain temperature.
Next, according to a fourth step described below, the sheet is peeled off, and development is performed until the film in the unexposed area is just removed. The development speed of the unexposed area is obtained from the time required for the development and the film thickness before development measured by a surface level meter across the scratch.
Next, the film thickness of the exposed area is measured to determine the speed at which the film thickness of the exposed area decreases. Here, the development speed difference between the exposed area and the unexposed area is obtained, and the condition for increasing the value can be found.
A method is recommended in which the wafer is finely cut, samples with different exposure amounts, PEB times and temperatures are prepared, and the above conditions for increasing the development speed are found.

(4) Developing step (fourth step)
As a fourth step, the unexposed portion is eluted or removed with an organic solvent. Subsequently, a desired relief pattern is obtained preferably by rinsing with a rinsing liquid. As a developing method, a spray, paddle, dip, or ultrasonic method can be used.
The developer used for developing the photosensitive resin layer made of the photosensitive resin composition is selected from the polyethersulfone solvents (the (D) solvent described above).
Thereafter, optionally, the relief pattern formed by development may be washed with a rinse solution to remove the developer. As the rinsing liquid, methanol, ethanol, isopropanol, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether or the like is used alone or in combination.

In addition, the relief pattern obtained for the purpose of increasing the thermogravimetric decrease temperature can be heat-treated. As a heating device, an oven furnace, a hot plate, a vertical furnace, a belt conveyor furnace, a pressure oven, or the like can be used. As a heating method, heating by hot air, infrared rays, electromagnetic induction, or the like is recommended. The temperature is preferably 200 to 450 ° C, more preferably 250 to 400 ° C. The heating time is preferably 15 minutes to 8 hours, more preferably 1 to 4 hours. The atmosphere is preferably in an inert gas such as nitrogen or argon.
A semiconductor device combines a relief pattern with a known manufacturing method of a semiconductor device as a surface protective film, an interlayer insulating film, a rewiring insulating film, a protective film for a flip chip device, or a protective film for a device having a bump structure. Can be manufactured.
The photosensitive resin composition of the present invention is also useful for applications such as interlayer insulation of multilayer circuits, cover coating of flexible copper-clad plates, solder resist films, or liquid crystal alignment films.

The present invention will be described more specifically based on synthesis examples, examples, comparative examples, and reference examples.
[Synthesis Example 1]
(Synthesis of crosslinking agent)
A crosslinking agent was synthesized according to the following procedure.
(I) Synthesis of 4,4′-methylenebis [2,6-bis (hydroxymethyl) phenol] (hereinafter also referred to as “MBHP”): 36 g of 37 mass% aqueous formaldehyde solution, 2.2 g of sodium hydroxide, and 11.0 g of bisphenol F was added to a 200 ml Erlenmeyer flask containing a mixture of 30 ml of water, and stirred at room temperature for 24 hours. The reaction mixture was extracted with ethyl acetate, and the extract was dried over magnesium sulfate. Magnesium sulfate was filtered off and concentrated using a rotary evaporator under reduced pressure, and the product was isolated by column chromatography (silica gel column, developing solution: hexane / ethyl acetate). The obtained product was recrystallized using hexane / propanol to obtain a white solid.

(Ii) Synthesis of 4,4′-methylenebis [2,6-bis (methoxymethyl) phenol] (hereinafter also referred to as “MBMP”): 3 liters of 1 liter equipped with a stirrer, a thermometer, and a reflux condenser 500 ml of methanol and 1.75 g of concentrated sulfuric acid were added to the flask, and 5.0 g of MBHP synthesized in the above (i) was added thereto to obtain a homogeneous solution. Next, stirring was continued at 60 ° C. for 20 hours.
Thereafter, methanol was removed under reduced pressure from the resulting reaction mixture at room temperature using a rotary evaporator. The product was then extracted with a separatory funnel using methylene chloride. The organic layer was washed with 1% aqueous sodium hydrogen carbonate solution followed by water and dried over anhydrous magnesium sulfate. After filtering off magnesium sulfate, the organic layer was concentrated using a rotary evaporator under reduced pressure. This concentrated solution was separated and purified by column chromatography and dried to obtain a highly pure product. As a developing solution, a 3/2 (volume) hexane / ethyl acetate mixed solution was used. The yield was 5.11 g (87% yield). The melting point was 36.5-37.5 ° C. Infrared absorption spectrum of the product (cm ⁻¹ ; KBr method): 1083, 1222, 1485, 1608, 2827, 2989, 3355. Proton NMR chemical shift (300 MHz, CDCl ₃ solution; ppm): 3.42 (12H, s), 3.78 (2H, s), 4.55 (8H, s), 6.92 (4H, s), 7.67 (2H, s). C ¹³ NMR chemical shift (75 MHz, CDCl ₃ solution; ppm) 40.59, 58.75, 72.35, 123.93, 129.22, 132.89, 136.16, 152.94 Elemental analysis value: C ; 66.90%, H; 7.47% calculated _{(C 21 H 28 O 6)} : C; 67.00%, H; 7.50%. From the above analysis, the product was identified as MBMP.

[Example 1]
(Adjustment of photosensitive resin composition and evaluation of developability 1)
In a 20 ml glass sample bottle, 8.00 g of cyclopentanone and 1.60 g of PEES (polyethersulfone described below), 0.30 g of MBMP prepared in Synthesis Example 2, diphenyliodonium-9,10 represented by the following formula -Dimethoxyanthracene-2-sulfonate (hereinafter also referred to as "DIAS") (Toyo Gosei Co., Ltd.) 0.10 g is added, and the sample bottle is made uniform using a mix rotor (As One Co., Ltd. MR-5) It rotated and adjusted the negative photosensitive composition. This mixture was spin-coated on two 8-inch silicon wafers with a spin coater (1H-D7 manufactured by Mikasa Co., Ltd.) at a rotation speed of 8000 rpm for 30 seconds, and prebaked in air at 80 ° C. for 60 seconds in a thickness. A 2.2 μm coating film was formed. A filter was applied to the ultra high pressure mercury lamp, and only 365 nm i-line was taken out and exposed to a wafer in which half of the coating film was shielded from light with an exposure amount of 300 mJ / cm ² . The wafer was divided so that the exposed portion and the light shielding portion were included in each piece, and each wafer piece was subjected to PEB at various temperatures of 130 to 180 ° C. for 3 minutes using a hot plate. Next, each wafer piece was immersed in DMAc for 2 seconds at room temperature. As shown in FIG. 1, the vertical axis is the Dissolution rate and the horizontal axis is the PEB temperature, and the thickness before and after the development of the wafer piece including each exposure part and the light-shielding part is measured to determine the film dissolution rate. Was calculated and plotted against the temperature of the PEB (□ indicates no exposure and ◆ indicates exposure). As a result, when PEB was performed in the range of 160 to 180 ° C., it was confirmed that the ratio of the dissolution rate between the unexposed area and the exposed area was 10,000 times or more.

The PEES used here is SIGMA-Aldrich Co. Ltd .. Purchased from the company.
The molecular weight was measured using gel permeation chromatography (apparatus: JASCO co-2006 column: TOSOH TSK gel GMH _HR- M) using DMF as a developing solution. The number average molecular weight and the weight average molecular weight were 34,700, 60,700. The repeating structure of this polyethersulfone is represented by the following formula (III).

[Example 2]
(Adjustment of photosensitive resin composition and evaluation of developability 2)
A coating film was formed on the wafer in the same manner as in Example 1 except that 1.70 g of PPES, 0.20 g of MBMP and 0.10 g of DIAS were used.
The PEB temperature was 160 ° C., and PEB was performed in the same manner as in Example 1 under various conditions for 0 to 20 minutes.
The exposure amount was 300 mJ / cm ^2, the development time was 2 seconds, and the dissolution rate was measured in the same manner as in Example 1. The results are shown in FIG. 2 (Dissolution rate on the vertical axis and PEB time on the horizontal axis. □ indicates no exposure and ◆ indicates exposure). As a result, it was confirmed that the ratio of the dissolution rate between the unexposed area and the exposed area was about 9800 times with PEB for 12 to 20 minutes.
Moreover, the result of having conducted the same experiment at 170 degreeC PEB temperature is shown in FIG. It was confirmed that the ratio of the dissolution rate between the unexposed area and the exposed area was about 12000 times after 3 to 20 minutes of PEB.

[Example 3]
(Adjustment of photosensitive resin composition and evaluation of developability 3)
A coating film was formed on the wafer in the same manner as in Example 1 except that 1.60 g of PEES, 0.30 g of MBMP, and 0.10 g of DIAS were used.
PEB was carried out at 170 ° C. for 3 minutes, the exposure amount was 300 mJ / cm ² , the development time was 2 seconds, and the dissolution rate was measured in the same manner as in Example 1. The result is shown in FIG. It was confirmed that the ratio of the dissolution rate between the unexposed area and the exposed area was about 12000 times.

[Example 4]
(Sensitivity evaluation of photosensitive resin composition)
The photosensitive resin composition of Example 2 was spin-coated on an 8-inch silicon wafer with a spin coater (1H-D7 manufactured by Mikasa), pre-baked at 80 ° C. for 60 seconds with a hot plate, and a film thickness of 2.5 μm. A film was formed. The film thickness was measured with a film thickness measuring device (Dektak 3 system manufactured by Veeco Instruments Inc.).
This coating film was exposed with various exposure amounts using a contact exposure machine (mask alignment apparatus M-1S manufactured by Mikasa Co., Ltd.) having an exposure wavelength of i-line (365 nm) through a reticle with a test pattern. Further, PEB was performed at 170 ° C. for 3 minutes. This was developed with DMAc for 2 seconds, and the film thickness at each exposure amount was measured. The obtained sensitivity curve is shown in FIG. Here, the vertical axis indicates (relative film thickness) by (film thickness after exposure / development / film thickness before exposure) × 100 (%), and the horizontal axis indicates exposure dose. From this figure, D ₅₀ (exposure amount at which the relative film thickness becomes 50%) was 21 mJ / cm ² and the γ value was 2.1. The definition of the γ value is described in p60 of Non-Patent Document 2, but here it is defined as the slope of the tangent line of the graph at the point where the relative film thickness is 50%.

Example 5
(Evaluation of resolution of photosensitive resin composition)
The photosensitive resin composition of Example 2 was spin-coated on an 8-inch silicon wafer with a spin coater, and prebaked at 80 ° C. for 60 seconds with a hot plate to form a film with a thickness of 2.5 μm.
This coating film was exposed to 150 mJ / cm ² using a contact exposure machine (mask alignment apparatus M-1S manufactured by Mikasa) having an exposure wavelength of i-line (365 nm) through a reticle with a test pattern. Further, PEB was performed at 170 ° C. for 3 minutes. This was developed with DMAc for 15 seconds to form a relief image. It was confirmed by the observation with an electron microscope that resolution was achieved up to a line / space pattern of 4 μm / 4 μm.

[Example 6]
(Evaluation of dynamic viscoelasticity of film obtained from photosensitive PEES composition)
The photosensitive resin composition prepared in Example 2 was applied to a glass plate with a bar coater, and prebaked on a hot plate at 40 ° C., 80 ° C., 100 ° C., and 135 ° C. for 30 seconds each. Next, exposure of 1000 mJ / cm ² was performed on the entire surface with i-line. Next, PEB was performed on a hot plate at 170 ° C. for 15 minutes.
A test piece having a length of 30 mm, a width of 10 mm, and a film thickness of 60 μm was cut out from the obtained film.
Using this film as a sample, a dynamic viscoelasticity measuring apparatus (model: DMS6300, manufactured by Seiko Instruments Inc.) was used to measure the dynamic viscoelasticity at a frequency of 1 Hz while raising the temperature at a rate of 2 ° C./min. The result is shown in FIG.
The storage elastic modulus (E ′) at 50 ° C. was 1.7 GPa, indicating good mechanical properties. The glass transition point (Tg) obtained from the peak of the loss modulus (E ″) is 220 ° C., which is the same value as the PEES shown in Reference Example 1 below, and the relief pattern is good for PEES which is a matrix polymer. It became clear that heat resistance was maintained.

[Reference Example 1]
(Evaluation of dynamic viscoelastic performance of PEES film)
PEES used in Example 1 was dissolved in cyclopentanone to prepare a solution having a solid content of 20%. This solution was applied to a glass plate with a bar coater, and prebaked at 40 ° C., 80 ° C., 100 ° C., and 135 ° C. for 30 seconds on a hot plate.
Next, it vacuum-dried at 60 degreeC for 2 hours.
A test piece of the same size as in Example 6 was cut out and measured in the same manner as in Example 6. The result is shown in FIG. The storage elastic modulus (E ′) at 50 ° C. was 1.0 GPa. And the glass transition point (Tg) calculated | required from the peak of loss elastic modulus (E '') was 220 degreeC.

[Reference Example 2]
(Evaluation of thermal weight loss of photoacid generator)
Thermal stability was evaluated with a thermogravimetric analyzer while flowing 100 ml of air per minute using DIAS and PTMA represented by the following formula. The results are shown in FIG. 6 (the weight loss (%) on the vertical axis and the temperature (° C.) on the horizontal axis). PTMA started to lose weight from around 150 ° C. and suddenly decreased from around 195 ° C. On the other hand, DIAS started to decrease in weight from around 190 ° C and suddenly decreased from around 220 ° C. The slight weight loss of DIAS near 100 ° C. is considered to be due to the volatilization of moisture.

  The photosensitive resin composition of this invention can be used conveniently for manufacture of the protective film of a semiconductor, and the insulating film of a package.

The dissolution rate of the film | membrane after performing PEB for 3 minutes of the photosensitive resin composition coating film of Example 1 was plotted with respect to the temperature (PEB temperature) of PEB. □ indicates data on a film that was not exposed, and ◆ indicates data on a film that was exposed at 300 mJ / cm ² with i-line. A plot of the dissolution rate of the film against the PEB time when PEB of the photosensitive resin composition coating film of Example 2 was carried out at 160 ° C. and development was fixed at 2 seconds. It is. □ indicates data on a film that was not exposed, and ◆ indicates data on a film that was exposed at 300 mJ / cm ² with i-line. A plot of the dissolution rate of the film against the PEB time when PEB of the photosensitive resin composition coating film of Example 3 was carried out at 170 ° C. and development was fixed at 2 seconds. It is. □ is data on a film that was not exposed, and ◆ is data on a film that was exposed at 300 mJ / cm ² with i-line. The photosensitive resin composition coating film of Example 2 was exposed at various exposure amounts, subjected to PEB at 170 ° C. for 3 minutes, and the remaining film ratio relative to the exposure amount (Exposure Dose) when development was fixed at 2 seconds. (Normalized film thickness) is plotted. 3 is a chart obtained by measuring the temperature dependence of dynamic viscoelasticity of a film (Example 6) (also referred to as “PSPEES”) obtained from the photosensitive resin composition prepared in Example 2. FIG. ● is E ′ ◆ is E ″. ○ and ◇ are E ′ and E ″ of polysulfone PEES itself (Reference Example 1). The thermogravimetric analysis curves in the air of the two types of photoacid generators (DIAS and PTMA) of Reference Example 2 are shown (vertical axis: residual rate (%), horizontal axis is temperature (° C.)).

Claims (5)

(A) With respect to 100 parts by mass of polyethersulfone represented by the following general formula (I), (B) a CH ₂ OR group that causes a crosslinking reaction in the presence of an acid catalyst (where R is a carbon number of 1 to 4). A photosensitive resin composition comprising 2 to 40 parts by mass of a crosslinking agent having 2 to 20 parts by mass of a photoacid generator having a naphthalene nucleus or an anthracene nucleus.
(In the formula, m is 0 or 1, n is an integer of 10 to 400, and Ar is an aromatic group having 6 to 18 carbon atoms.)   2. The photosensitive resin composition according to claim 1, wherein (A) the polyethersulfone is represented by formula (I), wherein m is 1 and Ar is a biphenyl group. The photosensitive resin composition according to claim 1 or 2, wherein the (B) crosslinking agent has a CH ₂ OCH ₃ group that causes a crosslinking reaction in the presence of an acid catalyst.   (1) A photosensitive resin layer comprising the photosensitive resin composition according to any one of claims 1 to 3 is formed on a substrate, (2) exposed with actinic rays, and (3) 80 to 190 ° C. (4) Development is performed, and a relief pattern manufacturing method is provided.   A semiconductor device having a relief pattern obtained by the manufacturing method according to claim 4.