JP2019117334A - Method for manufacturing electronic device - Google Patents

Abstract

To reduce a recess occurring between semiconductor elements in the process of manufacturing an electronic device in which a photosensitive resin film is formed on semiconductor elements mounted on a substrate, exposed and developed, and then the photosensitive resin film is heated to cure.SOLUTION: The method for manufacturing an electronic device sequentially includes, in the described order: a film formation step of forming a photosensitive resin film comprising an epoxy resin on a surface of a substrate mounting semiconductor elements, the surface mounting the semiconductor elements, so as to obtain a substrate with the photosensitive resin film; an exposure step of exposing the photosensitive resin film; a development step of developing the exposed photosensitive resin film to obtain a patterned resin film; a first heating step of heating the patterned resin film; and a second heating step of heating the patterned resin film at a temperature higher than the temperature in the first heating step.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of manufacturing an electronic device. More specifically, the present invention relates to a method of manufacturing an electronic device using a photosensitive resin.

  Photosensitive resins are used in various aspects of the production of electronic devices. For example, a photosensitive resin may be used to fill and planarize "gaps" present in the electronic device or to seal members (elements, chips, etc.) in the electronic device.

For example, Patent Document 1 describes that "embeddability" is improved using a photosensitive resin composition containing a specific acrylic polymer, a (meth) acrylate compound, an epoxy resin, and a photoinitiator. ing.
Further, in Patent Document 2, by arranging a film made of a photosensitive resin so as to cover the insulating portion and the conductive portion, even if there is a step in the object to be sealed, the step is caused by the step. It is described that it is possible to provide a semiconductor device with suppressed generation of voids and, in turn, excellent corrosion resistance.

JP, 2013-216804, A Unexamined-Japanese-Patent No. 2012-160761

As mentioned above, photosensitive resins are variously used in the manufacture of electronic devices.
However, according to the study of the present inventors, for example, as shown in FIG. 1, a photosensitive resin film is formed on a semiconductor element 2 (specifically, a semiconductor chip or the like) placed on the substrate 1. After forming 3 and performing exposure, development, etc. after that, when a photosensitive resin film is heated and hardened, a dent 5 may occur in a portion between semiconductor elements 2 (especially, FIG. 1 (b)) And Figure 1 (c)).
Such a recess can be a problem in terms of layering of the electronic device and improvement in reliability. In particular, when the photosensitive resin film 3 is thick, the depression 5 tends to be large, which may cause a serious problem.

  The present invention has been made in view of such circumstances. That is, in the process of manufacturing an electronic device according to the present invention, the photosensitive resin film is formed on the semiconductor element placed on the substrate, exposed and developed, and then the photosensitive resin film is heated and cured. An object of the present invention is to reduce a recess generated between semiconductor elements.

  As a result of intensive studies, the present inventors have found that the above-mentioned depression can be reduced by devising a method of heating a photosensitive resin film. Thereby, the invention provided below was completed and the said subject was solved.

According to the invention
A film forming step of forming a photosensitive resin film containing an epoxy resin on a surface of the substrate on which the semiconductor element is mounted on which the semiconductor element is mounted to obtain a substrate provided with the photosensitive resin film;
An exposure step of exposing the photosensitive resin film;
Developing the exposed photosensitive resin film to obtain a patterned resin film;
A first heating step of heating the patterned resin film;
A second heating step of heating the patterned resin film at a temperature higher than the first heating step;
There is provided a method of manufacturing an electronic device, comprising:

  According to the present invention, after a photosensitive resin film is formed on a semiconductor element placed on a substrate and exposed, developed, etc., in the process of manufacturing an electronic device in which the photosensitive resin film is heated and cured. Thus, it is possible to reduce the depressions generated between the semiconductor elements.

It is a schematic diagram for demonstrating a subject of this invention, and a part of process of this invention. Fig.1 (a) and FIG.1 (b) are figures corresponding to the below-mentioned film forming process. FIG. 1 (c) is a diagram particularly showing “a recess formed between semiconductor elements” which is an object of the present invention. It is a figure for supplementing about a 1st heating process and a 2nd heating process. It is a figure for demonstrating the method of evaluation in an Example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the drawings, similar components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.
In order to avoid complexity, when there are a plurality of identical components in the same drawing, only one of them may be given a code and all of the components may not be given a code.
The drawings are for illustration only. The shapes, dimensional ratios, and the like of the respective members in the drawings do not necessarily correspond to real articles.

In the present specification, the term "abbreviation" means including a range in which manufacturing tolerances, assembly variations, and the like are taken into consideration, unless explicitly described.
In the present specification, the notation “a to b” in the description of the numerical range indicates a or more and b or less unless otherwise specified. For example, “1 to 5% by mass” means “1 to 5% by mass”.

In the notation of the group (atomic group) in the present specification, the notation not describing whether substituted or unsubstituted is intended to encompass both those having no substituent and those having a substituent. For example, the "alkyl group" includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group).
The expression "(meth) acrylic" in the present specification represents a concept including both acrylic and methacrylic. The same applies to similar notations such as "(meth) acrylate".
The term "electronic device" in the present specification means a device to which an electronic technology is applied, such as a semiconductor chip, a semiconductor device, a printed wiring board, an electric circuit display device, an information communication terminal, a light emitting diode, a physical battery, a chemical battery , Device, final product, etc.

<Method of Manufacturing Electronic Device>
The manufacturing method of the electronic device of the present embodiment is
A film forming process (hereinafter, simply referred to as obtaining a substrate provided with a photosensitive resin film by forming a photosensitive resin film containing an epoxy resin on the surface of the substrate on which the semiconductor element is mounted) Also referred to as "film forming process"),
An exposure step of exposing the photosensitive resin film (hereinafter, also simply referred to as “exposure step”);
Developing the exposed photosensitive resin film to obtain a patterned resin film (hereinafter, also simply referred to as “development step”);
A first heating step (hereinafter, also simply referred to as "first heating step") of heating the patterned resin film;
A second heating step (hereinafter, also simply referred to as "second heating step") of heating the resin film patterned at a temperature higher than that of the first heating step;
In this order.

  The reason why the above-mentioned "dents generated between semiconductor elements" is reduced by such a step can be explained as follows, although not all is clear.

With regard to thermal curing of a photosensitive resin film containing an epoxy resin, curing proceeds as the heating temperature is higher. However, the photosensitive resin film before curing contains many low molecular weight components. Therefore, it is considered that part of the low molecular weight component is released (volatilized) out of the system by heating.
When a photosensitive resin film containing an epoxy resin is formed on a flat substrate, it is considered that there is little problem even if part of the low molecular weight component is released out of the system (low molecular weight in flat substrate) If the components are uniformly released, the film thickness should not differ from place to place). However, as described in the subject of the present invention, when the photosensitive resin film is formed on the substrate on which the semiconductor element is mounted (in other words, there is a step), the film thickness of the resin film varies depending on the place. In some cases, it may be different in the way the low molecular weight component is released depending on the place. This is presumed to be the cause of the aforementioned depression.

  In the method of manufacturing an electronic device of the present embodiment, the resin film is heated to a relatively low temperature in the first heating step to cure the resin film to some extent while suppressing the release (volatilization) of the low molecular weight component. Then, in the second heating step, the resin film is heated at a relatively high temperature to obtain a sufficiently cured state. It is believed that these two-step heat curing can reduce the problem of dents and obtain a cured film that is sufficiently cured.

In addition, if it is only for the purpose of suppressing the release (volatilization) of low molecular weight components, it is considered that only two-stage heat curing at relatively low temperature and relatively high temperature is not performed, and only heat curing at relatively low temperature is performed. Be
However, in such a case, there is a concern that the curing reaction itself may be insufficient. If the curing is insufficient, for example, the glass transition temperature of the cured film becomes low, which may cause problems in the heat resistance of the cured film and the reliability during mounting.
In the method of manufacturing an electronic device of the present embodiment, the two-stage heat curing can not only reduce the dent but also allow the curing reaction itself to sufficiently proceed, thereby raising the glass transition temperature of the cured film ( As a result, it is considered that the heat resistance of the cured film and the reliability in mounting can be improved.

Each step will be described more specifically below.
In addition, in description of a film forming process, FIG. 1 is partially referred and FIG. 2 is partially referred for description of a 1st heating process and a 2nd heating process, but drawing is especially referred in description of a process other than that. Do not refer to.

(Film forming process)
The manufacturing method of the electronic device of this embodiment can include a film forming process.
Specifically, as shown in FIG. 1B, the photosensitive resin film 3 can be formed on the surface of the substrate 1 on which the semiconductor element 2 is mounted, on which the semiconductor element 2 is mounted. .

The substrate 1 may be any substrate, for example, silicon wafer, silicon oxide wafer, silicon nitride wafer, FR4 (Flame Retardant Type 4), which is impregnated with an epoxy resin in a glass fiber cloth and thermally cured. (Such as a plate-like). Wiring, a circuit structure, etc. may be formed on the substrate 1.
The size and the like of the semiconductor element 2 are not particularly limited, but typically, the vertical and horizontal sizes in top view are respectively about 5 to 30 mm, and the heights in side view are about 10 to 200 μm. It is.
The substrate 1 and the semiconductor element 2 may or may not be connected by any means.

The film formation here is mainly performed by one of the following two methods.
(I) Using the film-like photosensitive resin composition 3A (FIG. 1A), a film is formed by a lamination method.
(Ii) A film is formed by applying a liquid photosensitive resin composition on the surface of the substrate 1 on which the semiconductor element 2 is mounted, on which the semiconductor element 2 is mounted (not shown).

In the method of manufacturing an electronic device of the present embodiment, the film forming step may be performed by any of the methods described above. However, in view of securing the flatness of the resin film surface (this is a critical issue in particular when the resin film is thick, the area of the substrate is large, etc.), film formation by the lamination method of (i) is preferable .
Hereinafter, the case of performing the film forming process by the laminating method will be described in more detail.

The film-like photosensitive resin composition (the photosensitive resin composition 3A in FIG. 1 (a)) is, for example, a liquid photosensitive resin composition on a suitable support film (synthetic resin film such as PET film etc.) It can be obtained by applying an article with a substantially constant film thickness and drying it. At this time, known coating devices such as a roll coater and a comma coater can be used for coating. Moreover, the photosensitive resin composition may affix a surface protection film (PET film etc.) on the surface opposite to the surface in contact with the support film. By doing this, it is possible to prevent the appearance deterioration due to the external force during storage.
The component etc. which are contained in the photosensitive resin composition apply | coated here are mentioned later.

  The thickness of the photosensitive resin composition for lamination is appropriately adjusted depending on the height of the mounted semiconductor element (semiconductor element 2 in FIG. 1) and the like, but for example 3 to 500 μm, more preferably 5 to 300 μm, and further more Preferably it is 10-200 micrometers.

The film-like photosensitive resin composition formed on the support film is arranged to be in direct contact with the surface of the substrate on which the semiconductor element is mounted, on which the semiconductor element is mounted. And a photosensitive resin film can be formed on a board | substrate by the lamination process using a vacuum lamination apparatus etc.
The conditions for vacuum lamination are, for example, a pressure of 0.1 to 1.0 MPa, a temperature of 50 to 120 ° C., and a time of 10 to 90 seconds.
After this laminating process, the support film is usually peeled off.

The component etc. of the photosensitive resin composition for forming a photosensitive resin film are demonstrated.
The photosensitive resin composition contains at least an epoxy resin. Further, it is preferable to contain a curing agent, a photosensitizer and the like. Furthermore, other components such as adhesion assistants and surfactants may be included. When the photosensitive resin composition is liquid, it is preferable that the photosensitive resin composition further contains a solvent.
Hereinafter, the components and the like will be described more specifically.

-Epoxy resin As an epoxy resin, what has an epoxy group two or more in 1 molecule can be used, for example.
Specifically, phenol novolak type epoxy resin, cresol novolac type epoxy resin, cresol naphthol type epoxy resin, biphenyl type epoxy resin, biphenylaralkyl type epoxy resin, phenoxy resin, naphthalene skeleton type epoxy resin, bisphenol A type epoxy resin, bisphenol A diglycidyl ether type epoxy resin, bisphenol F type epoxy resin, bisphenol F diglycidyl ether type epoxy resin, bisphenol S diglycidyl ether type epoxy resin, glycidyl ether type epoxy resin, cresol novolac type epoxy resin, aromatic polyfunctional epoxy resin And aliphatic epoxy resins, aliphatic polyfunctional epoxy resins, alicyclic epoxy resins, polyfunctional alicyclic epoxy resins and the like.
The epoxy resins may be used alone or in combination of two or more.

Moreover, an epoxy resin can contain the trifunctional or more than trifunctional polyfunctional epoxy resin.
Specifically, 2- [4- (2,3-epoxypropoxy) phenyl] -2- [4- [1,1-bis [4-([2,3-epoxypropoxy] phenyl) ethyl] phenyl] Propane, phenol novolac epoxy, tetrakis (glycidyloxyphenyl) ethane, α-2,3-epoxypropoxyphenyl-ω-hydropoly (n = 1-7) {2- (2,3-epoxypropoxy) benzylidene-2, Examples thereof include 3-epoxypropoxyphenylene}, 1-chloro-2,3 epoxypropane formaldehyde, 2,7-naphthalenediol polycondensate, and dicyclopentadiene type epoxy resin.
The polyfunctional epoxy resin may be used alone or in combination of two or more.

  Further, the epoxy resin may be a resin containing a siloxane structure, a resin containing a silphenylene structure, or the like. More specifically, a resin containing a siloxane structure and a resin containing a silphenylene structure, which are described in claim 4 and paragraph 0055 of patent 6031059, can be preferably used.

  The lower limit of the content of the epoxy resin is, for example, 40% by mass or more, preferably 45% by mass or more, and more preferably 50% by mass or more, based on the total solid content of the photosensitive resin composition. . Thereby, in the hardened | cured material of the photosensitive resin composition, heat resistance and mechanical strength can be improved. On the other hand, the upper limit of the content of the epoxy resin is, for example, 80% by mass or less, preferably 75% by mass or less, and more preferably 70% by mass, based on the total solid content of the photosensitive resin composition. It is below. By appropriately adjusting the content, the patternability of the photosensitive resin composition can be improved.

  In addition, "solid content" means here the remainder except water and the organic solvent from a composition. The same applies to other components other than epoxy resin.

Curing Agent The curing agent is not particularly limited as long as it accelerates the polymerization reaction of the epoxy resin.
For example, a curing agent having a phenolic hydroxyl group can be included. More specifically, a phenol resin can be used. The phenol resin can be appropriately selected from known ones, and for example, novolac type phenol resin, resol type phenol resin, trisphenylmethane type phenol resin, and aryl alkylene type phenol resin can be used. In addition, low molecular weight phenolic compounds (polynuclear phenolic compounds) can also be used.

The curing agent is preferably, in one aspect, a novolac type phenolic resin having good development characteristics.
Further, as another embodiment, low molecular weight phenol compounds (low molecular weight compounds containing about 2 to 5 benzene rings and 2 to 6 or more phenolic hydroxyl groups) as exemplified below are also preferably used.

  The content of the curing agent is, for example, 25 to 100 parts by mass, preferably 30 to 90 parts by mass, and more preferably 35 to 80 parts by mass, based on 100 parts by mass of the entire epoxy resin. By blending in this range, improvement in heat resistance and strength of the cured product can be expected.

Photosensitizer As a photosensitizer, a photoacid generator, that is, a compound capable of generating an acid upon irradiation with an actinic ray such as ultraviolet light can be used.
Specifically, onium salt compounds and the like can be mentioned. More specifically, iodonium salts such as diazonium salts and diaryliodonium salts, sulfonium salts such as triarylsulfonium salts, triarylbirylium salts, benzyl pyridinium thiocyanate, dialkyl phenacyl sulfonium salts, dialkyl hydroxyphenyl phosphonium salts and the like be able to.

  Moreover, as a photo-acid generator, the photo-acid generator which has an oxime sulfonate structure, the photo-acid generator which has an imido sulfonate structure, etc. can also be mentioned. As a specific structure of these photo-acid generators, the following can be mentioned, for example.

  As the photosensitizer, those which do not generate hydrogen fluoride due to decomposition are preferable. Thereby, corrosion of the substrate and the like can be reduced.

The lower limit of the content of the photosensitizer is, for example, 0.3% by mass, preferably 0.5% by mass, and more preferably 1% by mass, relative to the total solid content of the photosensitive resin composition. . Thereby, in the photosensitive resin composition, the patterning property can be improved.
The upper limit of the content of the photosensitizer is, for example, 20% by mass, preferably 15% by mass, and more preferably 10% by mass, based on the total solid content of the photosensitive resin composition. Preferably it is 5 mass%. This makes it easier to balance sensitivity with other performance.

-Adhesion assistant The adhesion assistant is not particularly limited. For example, silane coupling agents such as aminosilane, epoxysilane, acrylic silane, mercaptosilane, vinylsilane, ureidosilane, acid anhydride functional silane, and sulfide silane can be used. One type of silane coupling agent may be used alone, or two or more types may be used in combination. Among these, epoxysilane (that is, a compound that contains both an epoxy site and a group that generates a silanol group by hydrolysis in one molecule) or an acid anhydride functional silane (that is, an acid anhydride in one molecule) Compounds which contain both an organic group and a group which generates a silanol group by hydrolysis are preferred.

  As the aminosilane, for example, bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-amino Propylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, Examples include N-β (aminoethyl) γ-aminopropylmethyldiethoxysilane or N-phenyl-γ-amino-propyltrimethoxysilane.

  As epoxysilane, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, or β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidylpropyltrimethoxy Silane etc. are mentioned.

  Examples of acrylic silanes include γ- (methacryloxypropyl) trimethoxysilane, γ- (methacryloxypropyl) methyldimethoxysilane, and γ- (methacryloxypropyl) methyldiethoxysilane.

  As a mercaptosilane, 3-mercaptopropyl trimethoxysilane etc. are mentioned, for example.

  Examples of the vinylsilane include vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, and vinyltrimethoxysilane.

  Examples of ureidosilanes include 3-ureidopropyltriethoxysilane and the like.

  As an acid anhydride functional type silane, 3-trimethoxy silyl propyl succinic acid anhydride etc. are mentioned, for example.

  Examples of sulfide silanes include bis (3- (triethoxysilyl) propyl) disulfide, or bis (3- (triethoxysilyl) propyl) tetrasulfide.

  The content of the adhesion promoter is generally 0.01 to 5% by mass, preferably 0.05 to 3% by mass, based on the total solid content of the photosensitive resin composition. By setting this range, it is considered that "adhesion", which is the effect of the adhesion aiding agent, can be sufficiently obtained while maintaining balance with other performances.

-Surfactant The photosensitive resin composition containing a surfactant can be expected to improve the uniformity of the thickness of the resin film.
The surfactant is preferably a nonionic surfactant containing at least one of a fluorine atom and a silicon atom. Examples of commercially available products include F-251, F-253, F-281, F-430, F-477, F-551, F-552, and F-553 in the "Megafuck" series manufactured by DIC Corporation. , F-554, F-555, F-556, F-557, F-558, F-559, F-560, F-562, F-562, F-563, F-565, F-568, F Fluorine-containing oligomeric structures such as -569, F-570, F-572, F-574, F-575, F-576, R-40, R-40-LM, R-41, R-94, etc. Surfactants, fluorine-containing nonionic surfactants such as Futergent 250 made by Neos Co., Ltd., Futergent 251, etc., SILFOAM (registered trademark) series made by Wacker Chemie (eg SD 100 TS, SD 670, etc.) D 850, SD 860, SD 882) silicone surfactant and the like.

  The content of the surfactant is usually 0.01 to 5% by mass, preferably 0.05 to 3% by mass, based on the total solid content of the photosensitive resin composition. By setting this range, it is considered that effects such as improvement in the uniformity of the thickness of the resin film can be sufficiently obtained while maintaining balance with other performances.

-Solvent When the photosensitive resin composition is in a liquid state, the photosensitive resin composition preferably further contains a solvent.
The solvent is typically an organic solvent. Specifically, ketone solvents, ester solvents, ether solvents, alcohol solvents, lactone solvents, carbonate solvents and the like can be used.

More specifically, acetone, methyl ethyl ketone, toluene, propylene glycol methyl ethyl ether, propylene glycol dimethyl ether, butyl acetate, propylene glycol 1-monomethyl ether 2-acetate, diethylene glycol ethyl methyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate And organic solvents such as benzyl alcohol, propylene carbonate, ethylene glycol diacetate, propylene glycol diacetate, propylene glycol monomethyl ether acetate, anisole, N-methylpyrrolidone, cyclohexanone, cyclopentanone and the like.
When using a solvent, only 1 type may be used and 2 or more types may be used.

  When a solvent is used, the amount used is not particularly limited, but it is used, for example, in an amount such that the solid concentration is 30 to 85% by mass, preferably 40 to 80% by mass.

-Other components In addition to the above-mentioned components, the photosensitive resin composition may also contain other components as needed. Other components include crosslinking agents, basic compounds, curing accelerators, antioxidants, fillers such as silica, sensitizers, film forming agents, and the like.

Among the above, as the crosslinking agent, compounds having a plurality of (typically 2 to 6) partial structures of —N—CH ₂ —OH can be mentioned. More specifically, commercially available melamine based crosslinking agents, glycoluril based crosslinking agents and urea based crosslinking agents can be mentioned.

  Among the above, as the basic compound, various amine compounds (eg, primary amine, secondary amine, tertiary amine, etc.) can be mentioned.

  Among the above, as the curing accelerator, a nitrogen-containing heterocyclic compound containing an amidine skeleton or a salt thereof can be mentioned. For example, 1,8-diazabicyclo [5,4,0] undecene-7 (another name: diazabicycloundecene, abbreviation: DBU), 6- (dibutylamino) -1,8-diazabicyclo [5,4,0] Undecen-7 (abbr .: DBA-DBU), 6- (2-hydroxypropyl) -1,8-diazabicyclo [5,4,0] undec-7-ene (abbr .: OH-DBU), 1,5-diazabicyclo [4,3,0] nonene-5 (abbreviation: DBN), phenol salt of DBU (specifically, trade name: U-CAT SA1 (manufactured by San Apro)), octoate of DBU (specifically, , Trade name: U-CAT SA 102 (manufactured by San Apro), p-toluenesulfonate of DBU (specifically, trade name: U-CAT SA 506 (manufactured by San Apro)), octylate of DBN Specifically, trade name: U-CAT 1102 (manufactured by San-Apro Ltd.)), and the like.

-Properties of Composition, etc. As described above, the properties of the photosensitive resin composition may be in the form of a film or liquid.
When film formation is performed by application, the photosensitive resin composition is usually in a liquid state and contains a solvent. Specific examples of the solvent are as described above.

Moreover, when film-forming by the above-mentioned lamination method, the photosensitive resin composition is a film form typically, and does not contain a solvent substantially. That is, it does not contain other than a certain amount of unavoidable residual solvents.
However, in order to obtain a film-like photosensitive resin composition, a solvent is usually required. That is, a solvent is required when apply | coating the photosensitive resin composition to a support film and producing the film for lamination (the film-like photosensitive resin composition is obtained).

(Exposure process)
The manufacturing method of the electronic device of the present embodiment can include an exposure step.
In the exposure step, typically, the photosensitive resin film formed in the above-mentioned film forming step is irradiated with an actinic ray through an appropriate photomask or the like. As a method of exposure through a photomask, a contact exposure method, a projection exposure method, a contact proximity exposure method and the like can be appropriately applied.

The exposure light source can be appropriately set based on the photosensitive characteristics of the photosensitive resin film and the like, and examples thereof include light having a wavelength of 100 to 1000 nm, more specifically g-line and i-line.
Exposure (dose) is also can be set as appropriate based on such photosensitive characteristics of the photosensitive resin film, for example, 10 to 10000 mJ / cm ^2, preferably 50 to 5000 mJ / cm ^2, more preferably 100~3000mJ / cm ²

  After the exposure process and before the development process, the photosensitive resin film may be heated as required. The temperature and time are, for example, 80 to 140 ° C. and about 10 to 300 seconds. Thereby, since the chemical reaction of the resin film is promoted, there are cases where it is possible to further improve the patterning performance (for example, the pattern shape).

(Development process)
The manufacturing method of the electronic device of this embodiment can include a development step.
The development can be carried out, for example, by a method such as immersion method, paddle method, rotary spray method and the like using a suitable developer. By development, the exposed portion (in the case of positive type image formation) or the unexposed portion (in the case of negative type image formation) of the resin film is removed, and a patterned resin film is obtained. In the method of manufacturing an electronic device according to the present embodiment, the unexposed area is usually removed by development to obtain a negative pattern.
The development time (time for bringing the developer into contact with the resin film) is preferably 0.5 seconds to 10 minutes, more preferably 1 second to 5 minutes.

The developer that can be used for development is not particularly limited. In one embodiment, an organic solvent developer (a developer containing 95% by mass or more of the organic solvent in the composition) can be used. Specific examples of the organic solvent include ketone solvents such as cyclopentanone, ether solvents such as propylene glycol monomethyl ether, and ester solvents such as propylene glycol monomethyl ether acetate and butyl acetate. In addition, a water-soluble organic solvent such as methanol or ethanol, a surfactant or the like may be added to the developer.
In the method of manufacturing the electronic device of the present embodiment, it is preferable to use an organic solvent developer.

  Further, an alkaline aqueous solution, for example, (i) inorganic alkaline aqueous solution such as sodium hydroxide, sodium carbonate, sodium silicate, ammonia etc., (ii) aqueous organic amine aqueous solution such as ethylamine, diethylamine, triethylamine, triethanolamine etc., (iii) tetra An aqueous solution of quaternary ammonium salts such as methyl ammonium hydroxide and tetrabutyl ammonium hydroxide can also be mentioned as the developer.

In the development step, it is preferable to sufficiently remove the developing solution by shaking off the developing solution or rinsing after the development.
The developer can be shaken off, for example, by rotating the substrate.
The rinse after development is performed, for example, by applying a rinse liquid to the substrate and the patterned resin by spin coating, spraying, immersion or the like. As the rinse solution, for example, distilled water, alcohols, ethers (for example, methanol, ethanol, isopropanol, propylene glycol monomethyl ether etc.) can be used.

(First heating step)
The method of manufacturing the electronic device of the present embodiment can include a first heating step.
The heating method may be any method. For example, an oven for heating, a hot plate, etc. can be mentioned. Also, the atmosphere of heating may be selected as appropriate. That is, heating can be performed under air, under an inert atmosphere of nitrogen, a rare gas, or the like, under reduced pressure, under vacuum, or the like.
Heating with an oven is preferable in terms of easiness of temperature control and easiness of creating an inert atmosphere.

The temperature of the first heating step is preferably in the range of 70 to 180 ° C., more preferably in the range of 120 to 180 ° C., and still more preferably in the range of 150 to 180 ° C.
By setting the temperature to 180 ° C. or less, the above-mentioned “volatilization of low molecular weight components” can be sufficiently reduced, and the effect of reducing the depression can be reliably obtained. Further, by setting the temperature to 70 ° C. or more, the reaction of the epoxy resin or the like can be advanced sufficiently fast, and improvement in throughput can be expected.

  In the first heating step, temperature variation may occur as long as it is within the above temperature range. That is, the first heating step does not have to be performed at a constant temperature. For example, heating may be performed such that the temperature is gradually raised from 70 ° C. to 180 ° C.

The time of the first heating step is preferably 30 to 120 minutes, more preferably 40 to 100 minutes, and still more preferably 45 to 90 minutes.
By performing the first heating step for 30 minutes or more, the low molecular weight component tends to stay in the system, and reacts with other components to easily achieve high molecular weight (that is, the volatilization of the low molecular weight component can be further suppressed). Therefore, it is thought that the effect of reduction of the above-mentioned dent can be acquired further. Further, by performing the first heating step in 120 minutes or less, improvement in throughput and the like can be expected.

(Second heating step)
The method of manufacturing the electronic device of the present embodiment can include a second heating step.
The heating method may be any method. As in the first heating step, a heating oven, a hot plate or the like can be used, and the heating atmosphere is not particularly limited. Heating with an oven is preferred in terms of ease of temperature control and the like.

The temperature of the second heating step is preferably in the range of 190 to 250 ° C., more preferably in the range of 190 to 230 ° C., and still more preferably in the range of 190 to 210 ° C.
By setting the heating temperature to 190 ° C. or more, the epoxy resin and the like in the photosensitive resin film can be sufficiently reacted, and the mechanical properties and the like of the cured product can be further improved. On the other hand, by setting the heating temperature to 250 ° C. or less, the volatilization of the low molecular weight component slightly remaining can be suppressed, and the effect of further reducing the depression can be obtained.
In the second heating step, as in the first heating step, the temperature may not be constant, and there may be temperature fluctuations (e.g., temperature increase).

The time of the second heating step is preferably 30 to 120 minutes, more preferably 40 to 100 minutes, and still more preferably 45 to 90 minutes.
By setting the above time, it is easy to achieve both the curing of the resin film and the throughput.

(Supplement about the 1st heating process and the 2nd heating process)
The 1st heating process and the 2nd heating process can be performed continuously as one mode.
For example, first, the first heating process is performed at a constant temperature using an oven, and then the setting temperature of the oven is raised, and the second heating process is performed continuously at a constant temperature higher than the first heating process. (Heating pattern 1).
Alternatively, the temperature of the oven may be raised continuously, and the first heating step and the second heating step may be performed separately (heating pattern 2).

  For reference, FIG. 2 shows a graph showing the relationship between the heating temperature and the time in the heating patterns 1 and 2 described above. These “continuous heating” are also formed in the above “patterned at a temperature higher than the first heating step of heating the patterned resin film and the first heating step in the method of manufacturing the electronic device according to the present embodiment. It is an aspect of "2nd heating process" which heats a resin film. For convenience, for example, a region where the heating temperature is less than 185 ° C. can be set as a first heating step, and a region where the heating temperature is 185 ° C. or more can be set as a second heating step.

  In the case where the first heating step and the second heating step are continuously performed, two steps are performed in one oven, so that it is possible to expect an advantage that new equipment investment and the like are unnecessary. In addition, since heating can be performed continuously in one oven, heating in an inert gas environment such as nitrogen gas can be continued more easily than in the other embodiments described below, and oxidation of the substrate and the resin film can be performed. There is also a merit that it is easy to hold down.

On the other hand, as another embodiment, the step of lowering the temperature of the substrate may be included between the first heating step and the second heating step. For example, the substrate is put into the first oven and used to perform the first heating step, and then the substrate is once taken out of the first oven (at this time, the temperature of the substrate is once lowered). Thereafter, the substrate may be placed in a second oven preheated to a higher temperature than the first oven to perform a second heating step.
In this case, since it is not necessary to perform the necessary “temperature rise of the oven” in the above-described embodiment, merits such as time reduction as the entire process and stability of the process can be expected.

(Other process)
The method of manufacturing the electronic device of the present embodiment may include steps other than the above. For example, a heat radiation process after heating, a process of making holes in the resin film, and the like may be included.

(About the mass reduction of the resin film)
As described above, it is considered that the method of manufacturing the electronic device of the present embodiment can suppress the volatilization of the low molecular weight component from the photosensitive resin film by devising the heating step.
In other words, according to the method of manufacturing an electronic device of the present embodiment, it is possible to suppress the decrease in mass of the photosensitive resin film due to heat curing.

  Specifically, according to the method of manufacturing an electronic device of the present embodiment, the reduction in mass of the resin film after the second heating step, based on the resin film after the developing step and before the first heating step, It can be 3.5% or less.

  The “less mass loss” (less volatilization from the photosensitive resin film) means not only that the above-mentioned dent problem is reduced, but also contamination of the manufacturing apparatus due to volatilization can be reduced. That is, it can be said that the method of manufacturing an electronic device of the present embodiment also has the effect of being able to reduce contamination of the manufacturing apparatus.

(Glass transition temperature of resin film)
The glass transition temperature of a cured film (cured film of a photosensitive resin film containing an epoxy resin) obtained through the method of manufacturing an electronic device of the present embodiment is typically 150 to 200 ° C.
In selecting the temperatures of the first heating step and the second heating step, it is also conceivable to use this glass transition temperature as a reference. For example, by setting the temperature of the first heating step lower than the glass transition temperature, molecular motion in the resin film is suppressed to further reduce volatilization of low molecular weight components, while the temperature of the second heating step is glass transition. By raising the temperature higher than the temperature, it is conceivable that the molecular motion is activated to make the remaining epoxy group easy to react.

  As mentioned above, although embodiment of this invention was described, these are the illustrations of this invention, and various structures other than the above can be employ | adopted. Furthermore, the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope in which the object of the present invention can be achieved are included in the present invention.

  Embodiments of the present invention will be described in detail based on examples and comparative examples. The present invention is not limited to the examples.

<Formation of Photosensitive Resin Film Containing Epoxy Resin>
First, the raw materials shown in Table 1 were dissolved in PGMEA (propylene glycol monomethyl ether acetate) to prepare a solution.
Next, the prepared solution was filtered with a polypropylene filter having a pore size of 0.2 μm to obtain a varnish-like photosensitive resin composition. The photosensitive resin composition was negative, and the solid content was 50% by mass.

  The sources of the epoxy resin, the curing agent, the photosensitizer, the surfactant and the coupling agent in Table 1, the chemical structure and the like are shown below.

  The solution prepared above was coated on a PET film (TR1 (a film thickness of 38 μm) manufactured by UNITICA) using a comma coater, and dried at 80 ° C. for 5 minutes. Thus, a film for lamination was produced. The film thickness was adjusted so that the thickness on the element of the photosensitive resin film obtained after the subsequent lamination was 10 μm. In addition, as a protective film, a PET film (Purex (registered trademark) A54, film thickness 38 μm) manufactured by Teijin Film Solutions Ltd. was attached to the surface of the photosensitive resin film opposite to the surface in contact with the support film for surface protection. .

Example 1: Implementation of Process
From the film forming step to the second heating step was performed based on the following procedure.

(1) Preparation of Substrate and Semiconductor Device As shown in FIG. 3, 101 pieces of semiconductor devices each measuring 10.5 mm × 8 mm in height and width (thickness) 150 μm on a silicon substrate having a diameter of 8 inches. Placed. Bonding of the device was performed using a known adhesive for connection as an adhesive.

(2) Film Forming Step First, the PET film as a protective film is peeled from the laminate film prepared in <Formation of photosensitive resin film containing epoxy resin>, and the surface of the photosensitive resin film not in contact with the support film. Exposed.
After that, the surface of the substrate prepared in (1) on which the semiconductor element was mounted was brought into close contact with the surface of the photosensitive resin film exposed above which was not in contact with the support film. Then, vacuum lamination was performed under the conditions of 70 ° C. and 0.4 MPa using a vacuum laminator device (MVLP-500 / 600 IIA manufactured by Meishin Machinery Co., Ltd.). After cooling, the PET film as the support film was peeled off. Thus, a photosensitive resin film containing an epoxy resin having a substantially flat surface and covering the substrate and the semiconductor element was formed.
The film thickness of the formed photosensitive resin film (film thickness of the place where the semiconductor element was not mounted) was 180 μm.

(3) Exposure Step Pattern exposure was performed on the photosensitive resin film provided in (2) through a photomask.
The exposure light source used NSR-4425i (made by NIKON). The light amount was 300 mJ / cm ² .
After exposure, post-exposure heating was performed on a hot plate at 70 ° C. for 5 minutes.

(4) Development Step The resin film obtained through the step of (3) was spray developed with PGMEA (propylene glycol monomethyl ether acetate) for 90 seconds to dissolve and remove the unexposed area.

(5) The substrate after the developing step of the heating step (4) above, was placed in an oven and the atmosphere N ₂ was replaced. Thereafter, the temperature was raised from room temperature to 170 ° C. at a rate of 5 ° C./minute, and then heated at 170 ° C. for 60 minutes to cure the resin film (first heating step).
Thereafter, the substrate was once taken out, allowed to cool to room temperature, and then put into an oven, and the atmosphere was replaced with N ₂ . Thereafter, the temperature was raised from room temperature to 200 ° C. at a rate of 5 ° C./minute, and then heated at 200 ° C. for 60 minutes to further cure the resin film (second heating step).

<Example 2: Implementation of Process>
In the heating step (5) of Example 1, without removing the substrate after the first heating step from the oven, the temperature of the oven is raised to 200 ° C., and the resin film is further cured for 60 minutes to perform the second curing step. The same process as in Example 1 was performed except for the above.

<Example 3: Implementation of Process>
The same process as in Example 1 was carried out except that “heating at 170 ° C. for 60 minutes” in the first heating step was set to “heating at 140 ° C. for 60 minutes” in Example 1.

Comparative Example: Process Execution
In Example 1, (5) the heating step is not performed in two steps, and the temperature is raised from room temperature to 200 ° C. at a rate of 5 ° C./min, and thereafter only curing at 120 ° C. is carried out at 120 ° C. , The process similar to Example 1 was implemented.

<Reference example: Implementation of process>
In Example 1, (5) the heating step is not performed in two steps, and the temperature is raised from room temperature to 170 ° C. at a rate of 5 ° C./min, and thereafter only curing in 120 minutes at 170 ° C. , The process similar to Example 1 was implemented.

<Evaluation: dent>
The surface roughness was measured in order to measure the surface asperities of the resin film cured by the process of the above-mentioned Example, Comparative Example or Reference Example. As a device, a surface roughness measuring device (part number: SURFCOM 1400G-64) sold by Tokyo Seimitsu Co., Ltd. was used.
The measurement measured the depth of a dent in the depth direction distance from the highest point to the lowest point between adjacent elements in five places of the part enclosed with the thick line of FIG. And the depth of a dent was quantitatively evaluated by the average value of the dent in three places except the maximum value and the minimum value among five places of dents.

<Evaluation: Weight reduction>
The mass reduction rate measurement at the time of heating was carried out using a differential thermal and thermal gravimetric simultaneous measurement apparatus (product number: STA7200RV) manufactured by Hitachi High-Technologies Corporation.
Specifically, using 10 mg of a sample obtained by pulverizing the film after the completion of the developing step of (4), the mass when heated at the same temperature rising rate, curing temperature and curing time as in (5) heating step The reduction rate was measured. However, in Examples 1 to 3 and Comparative Examples and Reference Examples in which the oven was once taken out of the substrate between the first heating step and the second heating step, after the first heating step up to room temperature with liquid nitrogen It was dropped sharply and a second heating step was performed.

<Evaluation: Glass transition temperature of cured film>
The glass transition temperature was measured using a thermomechanical device (product number: TMA / SS6000) manufactured by Seiko Instruments Inc. Specifically, when the temperature of the cured film obtained in each Example, Comparative Example, or Reference Example is raised from 30 ° C. to 400 ° C. at a heating rate of 5 ° C./min, the change in the thermal expansion of the film The bending point was taken as the glass transition temperature.

  The results of each evaluation are summarized in Table 3.

  As can be seen from Table 3, in Examples 1 to 3 in which the heating step was performed in two stages, the depression on the surface of the cured film could be significantly reduced as compared with the comparative example.

Further, by performing the heating process in two steps, data was obtained that the mass loss of the film was reduced compared to the comparative example. This is considered to be a supporting evidence that the above-mentioned "release of low molecular weight components in the film out of the system" is suppressed by carrying out the heating step in two steps.
As a result of suppressing the release of low molecular weight components out of the system, it is considered that contamination of the production apparatus due to volatilization can be reduced.

In addition, in the reference example which made the heating process only one step of low temperature (170 degreeC), although the dent was small, compared with the cured film obtained by Examples 1-3 and a comparative example, glass transition temperature has a glass transition. The temperature was a significantly lower value (the glass transition temperature differed by 10 ° C. or more despite using the same material).
This result is considered to indicate that the one-step heating at a low temperature suppressed the release of the low molecular components and thus the depression could be made small, but the curing reaction itself became insufficient.

1 substrate 2 semiconductor element 3 photosensitive resin film 3A photosensitive resin composition (film-like photosensitive resin composition)
5 dents

Claims (8)

A film forming step of forming a photosensitive resin film containing an epoxy resin on a surface of the substrate on which the semiconductor element is mounted on which the semiconductor element is mounted to obtain a substrate provided with the photosensitive resin film;
An exposure step of exposing the photosensitive resin film;
Developing the exposed photosensitive resin film to obtain a patterned resin film;
A first heating step of heating the patterned resin film;
A second heating step of heating the patterned resin film at a temperature higher than the first heating step;
A method of manufacturing an electronic device, comprising: A method of manufacturing an electronic device according to claim 1, wherein
The manufacturing method of the electronic device whose temperature of a said 1st heating process exists in the range of 70-180 degreeC. A method of manufacturing an electronic device according to claim 1 or 2, wherein
The manufacturing method of the electronic device whose time of a said 1st heating process is 30 to 120 minutes. A method of manufacturing an electronic device according to any one of claims 1 to 3, wherein
The manufacturing method of the electronic device whose temperature of a said 2nd heating process exists in the range of 190-250 degreeC. A method of manufacturing an electronic device according to any one of claims 1 to 4, wherein
The manufacturing method of the electronic device whose time of a said 2nd heating process is 30 to 120 minutes. A method of manufacturing an electronic device according to any one of claims 1 to 5, wherein
The manufacturing method of the electronic device to which said 1st heating process and said 2nd heating process are performed continuously. A method of manufacturing an electronic device according to any one of claims 1 to 5, wherein
A method of manufacturing an electronic device, comprising the step of lowering the temperature of the substrate between the first heating step and the second heating step. A method of manufacturing an electronic device according to any one of claims 1 to 7, wherein
The manufacturing method of the electronic device whose mass reduction of the resin film after the said 2nd heating process on the basis of the resin film after the said development process and before the said 1st heating process is 3.5% or less.

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