WO2018168115A1

WO2018168115A1 - Laminate, method for producing same and electronic component

Info

Publication number: WO2018168115A1
Application number: PCT/JP2017/044192
Authority: WO
Inventors: 多田羅　了嗣; 祐徳山下; 杉郎下田; 平井　剛
Original assignee: Jsr株式会社
Priority date: 2017-03-13
Filing date: 2017-12-08
Publication date: 2018-09-20

Abstract

The present invention is a method for producing a laminate, wherein a second substrate having an electrode pad is laminated on a first substrate having an electrode pad, with an underfill material being interposed therebetween. This method for producing a laminate comprises: a step (1) wherein a resist which comprises an opening that corresponds to the electrode pad of the first substrate is formed on the first substrate; a step (2) wherein a solder electrode is formed in a region of the first substrate, said region corresponding to the opening; a step (3) wherein an adhesive layer is formed on the solder electrode and/or the second substrate with use of an adhesive for underfill material formation, said adhesive containing inorganic particles and a dispersant that has a surface tension higher than the critical surface tension of the surface of the first substrate or the second substrate, said surface being in contact with the underfill material; and a step (4) wherein the second substrate is laminated on the first substrate such that the adhesive layer is sandwiched therebetween, thereby forming an electrical connection structure of the electrode pad of the first substrate and the electrode pad of the second substrate via the solder electrode. According to this method for producing a laminate, a fillet which is free from bleeding of an adhesive or the like and has a good shape is able to be formed, and therefore a laminate which has a fillet having a good shape is able to be produced.

Description

LAMINATE, MANUFACTURING METHOD THEREOF, AND ELECTRONIC COMPONENT

The present invention relates to a laminate, a manufacturing method thereof, and an electronic component.

In flip chip mounting, the chip and the substrate are reinforced with an adhesive called an underfill material in order to ensure connection reliability and mechanical strength between the chip and the substrate. Moreover, the location called a fillet is generally formed in the underfill material. The fillet is a portion of the underfill material that is formed larger than the chip and protrudes from the chip. The fillet plays an important role in ensuring connection reliability and mechanical strength between the chip and the substrate (Patent Document 1).

JP 2012-107149 A

¡In order to ensure the connection reliability and mechanical strength between the chip and the substrate, it is necessary to form a fillet with a good shape. Furthermore, when a plurality of chips are mounted on a substrate at a high density, it is necessary to form a fillet with a good shape. For example, if the underfill material protrudes more than expected and the fillet bleeds (bleeds), the connection reliability may be lowered.

The present invention provides an adhesive for forming an underfill material that can form a fillet with a good shape without bleeding, etc., and provides a method for producing a laminate having a fillet with a good shape. It is an object of the present invention to provide a laminate having a fillet of various shapes and an electronic component having the laminate.

The method for producing the laminate of the present invention comprises:
A method for manufacturing a laminate in which a second substrate having electrode pads is laminated on a first substrate having electrode pads via an underfill material,
Forming a resist having an opening corresponding to an electrode pad of the first substrate on the first substrate (1);
Forming a solder electrode on a portion of the first substrate corresponding to the opening (2);
On the solder electrode and / or on the second substrate,
Using an adhesive for forming an underfill material containing inorganic particles and a dispersant having a critical surface tension greater than a surface tension of a surface in contact with the underfill material in the first substrate or the second substrate Forming a layer (3), and laminating the second substrate on the first substrate across the adhesive layer, and via the solder electrodes, the electrode pads of the first substrate and the second substrate And (4) forming an electrical connection structure with the electrode pad.

In the method for manufacturing the laminated body, the step (2) may be a step (2 ′) of forming the solder electrode by filling the opening while heating the molten solder.
In the manufacturing method of the said laminated body, it is preferable that the said adhesive agent for underfill material formation contains an epoxy resin further, and also contains a hardening | curing agent.

In the method for manufacturing the laminate, it is preferable that the first substrate or the second substrate is a plasma processing substrate.
In the method for producing a laminate, the critical surface tension of the inorganic particles is preferably larger than the critical surface tension of the dispersant, and the critical surface tension of the inorganic particles is preferably 70 mN / m or more.

In the method for producing a laminate, the dispersant preferably has a surface tension of 45 to 70 mN / m.
In the method for manufacturing the laminated body, it is preferable that a critical surface tension of a surface in contact with the underfill material in the first substrate and the second substrate is less than 45 mN / m.

The laminate of the present invention comprises a laminate produced by the laminate production method, the first substrate and the second substrate via an underfill material formed from the underfill material-forming adhesive. It is a laminated body formed by laminating.
The electronic component of the present invention has the laminate.

According to the method for manufacturing a laminate of the present invention, it is possible to form a fillet having a good shape without an adhesive bleed, and a laminate having a good shape fillet can be manufactured.

FIG. 1 is a schematic cross-sectional view of a structure including a substrate in each step of the laminate manufacturing method according to the present invention. FIG. 2 is a photomicrograph obtained by bright field observation and dark field observation of the fillet of the laminate. FIG. 3 is a diagram showing the relationship between the critical surface tension of the SiN substrate and the elapsed time from the oxygen plasma treatment. FIG. 4 is a diagram showing the relationship between the critical surface tension of the SiN substrate, the surface tension of the dispersant, and the critical surface tension of the inorganic particles with or without bleed in the laminate.

[Manufacturing method of laminate]
The method for producing a laminate according to the present invention includes:
A method for manufacturing a laminate in which a second substrate having electrode pads is laminated on a first substrate having electrode pads via an underfill material,
Forming a resist having an opening corresponding to an electrode pad of the first substrate on the first substrate (1);
Forming a solder electrode on a portion of the first substrate corresponding to the opening (2);
On the solder electrode and / or on the second substrate,
Using an adhesive for forming an underfill material containing inorganic particles and a dispersant having a critical surface tension greater than a surface tension of a surface in contact with the underfill material in the first substrate or the second substrate Forming a layer (3), and laminating the second substrate on the first substrate across the adhesive layer, and via the solder electrodes, the electrode pads of the first substrate and the second substrate And (4) forming an electrical connection structure with the electrode pad.

The method for producing a laminate of the present invention is a method for producing a laminate in which a second substrate having electrode pads is laminated on a first substrate having electrode pads via an underfill material. That is, the laminate has a structure in which an underfill material is laminated on the first substrate, and the second substrate is laminated on the underfill material.

Further, the laminate manufacturing method of the present invention may correspond to a laminate manufacturing method by the IMS (Injection Molded Solder) method described in US Publication No. 2002/0109228.

In other words, the laminate manufacturing method of the present invention corresponding to the laminate manufacturing method by the IMS method includes the steps (1) to (4), and the step (2) applies molten solder to the opening. This is a step (2 ′) in which a solder electrode is formed by filling with heating.

The method for producing a laminate of the present invention includes the steps (1) to (4). Hereinafter, steps (1) to (4) will be described with reference to FIG.
(Process (1))
In the step (1), a resist having openings corresponding to electrode pads of the first substrate is formed on the first substrate.

For example, first, as shown in FIG. 1 (1-1), a coating film 3 of a photosensitive resin composition is formed on a first substrate 1 having electrode pads 2.
The first substrate 1 is, for example, a semiconductor substrate, a glass substrate, a silicon substrate, a substrate formed by providing various metal films or various elements on the surface of a semiconductor plate, a glass plate, and a silicon plate. The first substrate 1 has a large number of electrode pads 2.

The coating film 3 is formed by applying a photosensitive resin composition to the first substrate 1. The photosensitive resin composition may be a photosensitive resin composition conventionally used for forming a resist. The photosensitive resin composition usually includes a crosslinking agent such as a radically polymerizable compound such as a polyfunctional acrylate, or a cationic reactive compound such as methoxymethylmelamine or an epoxy resin, and is formed from the photosensitive resin composition. The coating film 3 is crosslinked in Step 2 described later. The coating method of the photosensitive resin composition is not particularly limited, and examples thereof include a spray method, a roll coating method, a spin coating method, a slit die coating method, a bar coating method, and an ink jet method. The film thickness of the coating film 3 is usually 0.1 to 100 μm, preferably 1 to 80 μm, more preferably 5 to 50 μm.

Subsequently, the coating film 3 is selectively exposed, further developed, and heated to form a resist 5 having an opening 4 in a region corresponding to each electrode pad 2 as shown in FIG. Form.

That is, the coating film 3 is partially exposed so that the openings 4 for accommodating the respective electrode pads 2 are formed, and thereafter developed and heated to form the openings 4 for accommodating the respective electrode pads 2. Form. As a result, a resist 5 having an opening 4 in a region corresponding to each electrode pad 2 is obtained. The opening 4 is a hole that penetrates the resist 5. The exposure, development and heating can be performed according to conventional methods. The maximum width of the opening 4 is usually 0.1 to 10 times, preferably 0.5 to 2 times the film thickness of the coating film 3.

(Process (2))
Step (2) is a step of forming a solder electrode 6 at a portion of the first substrate corresponding to the opening 4. Examples of the method for forming the solder electrode 6 include an electrolytic plating method, a solder paste imprinting method, a solder ball transfer method, and an IMS method.

Step (2 ′) is a step of forming the solder electrode 6 by the IMS method.
In the step (2 ′), the opening 4 is filled with molten solder while being heated. As shown in FIG. 1 (2-1), molten solder 9 is injected from the IMS head 8 into the opening 4. Thereafter, by cooling, solder electrodes 6 are formed in the openings 4 as shown in FIG. 1 (2-2). In the IMS method, filling is usually performed while heating the molten solder at 250 ° C. or higher.

There is no particular limitation on the method for filling the opening 4 while heating the molten solder, and a filling method other than the IMS method can also be adopted.
After step (2), the resist may be peeled off. The resist stripping method may be a conventionally used resist stripping method. Examples thereof include a wet process using a stripping solution and a dry process using ashing.

(Process (3))
In the step (3), underfill is applied on the solder electrode 6 or on the second substrate 11 having the electrode pads 12 or on the solder electrode 6 and the second substrate 11 having the electrode pads 12. A material forming adhesive is applied to form an adhesive layer.
If the resist is not removed after step (2), the resist 5 and the solder electrode 6 or the second substrate 11 having the electrode pad 12 or the resist 5 and the solder electrode 6 are removed. An adhesive for forming an underfill material is applied on the second substrate 11 having the electrode pads 12 and an adhesive layer.

FIG. 1 (3) shows a state in which an adhesive layer 7 is formed by applying an underfill material forming adhesive on the second substrate 11 having the electrode pads 12. Similar to the first substrate 1, the second substrate 11 is, for example, a semiconductor substrate, a glass substrate, a silicon substrate, a semiconductor plate, a substrate formed by providing various metal films on the surface of the glass plate and the silicon plate, and the like. .

The surface of the resist 5 and the solder electrode 6 and / or the second substrate 11 to which the underfill material forming adhesive is applied may be subjected to a pretreatment such as a plasma treatment in advance.

The adhesive layer 7 can be formed by applying an underfill material forming adhesive by a method such as a dipping method, a spin coating method, a spray coating method, a blade method, a dispensing method, or an ink jet method.

The underfill material-forming adhesive contains inorganic particles and a dispersant as fillers in addition to a binder as a main component. The dispersant stabilizes the dispersion of the inorganic particles.

The inorganic particles promote heat conduction from the semiconductor substrate and lower the temperature of the semiconductor substrate, thereby stably operating an electronic component having a stacked body formed by stacking the semiconductor substrates. In addition, the inorganic particles suppress deformation due to thermal expansion / contraction of the adhesive layer and improve the connection reliability of the electronic component.

Examples of the inorganic particles include at least one selected from the group consisting of metal, carbon, metal carbide, metal oxide, and metal nitride. Examples of carbon include carbon black, graphite, fullerene, diamond and the like. Examples of the metal carbide include silicon carbide, titanium carbide, tungsten carbide and the like. Examples of the metal oxide include magnesium oxide, aluminum oxide, silicon oxide, calcium oxide, zinc oxide, yttrium oxide, zirconium oxide, cerium oxide, ytterbium oxide, sialon (ceramics composed of silicon, aluminum, oxygen, and nitrogen). Etc. Examples of the metal nitride include boron nitride, aluminum nitride, and silicon nitride.

In the case where insulation is required, the inorganic particles are preferably oxides and nitrides. Examples of such inorganic particles include alumina (Al ₂ O ₃ ), aluminum nitride (AlN), boron nitride (BN), silicon nitride (Si ₃ N ₄ ), silica (SiO ₂ ), and the like.

The said inorganic particle may be used individually by 1 type, and may be used in combination of 2 or more type.
The number average particle diameter of the inorganic particles by dynamic light scattering is preferably 1 to 5,000 nm, more preferably 10 to 2,000 nm.

The content of the inorganic particles is usually 20 to 80% by mass in the solid content of the adhesive for forming the underfill material.
The dispersant has a function of stabilizing the dispersion of the inorganic particles and the binder.

The surface tension of the dispersant is such that the surface of the first substrate or the second substrate in contact with the underfill material, that is, the surface on which the adhesive layer is formed on the first substrate or the adhesive layer on the second substrate. It has the characteristic that it is larger than the critical surface tension of the formed surface. In FIG. 1 (3), the surface tension of the dispersant contained in the adhesive layer 7 is larger than the critical surface tension of the surface of the second substrate 11 on which the adhesive layer 7 is formed.

As described above, when the chip is mounted on the substrate, fillet bleeding may occur due to the underfill material protruding beyond the chip larger than expected. Such fillet bleed may cause a decrease in connection reliability.

It is estimated that the cause of the fillet bleeding is separation of the filler and the binder contained in the adhesive for forming the underfill material.
Fillet bleeds may or may not appear even when using the same underfill. The inventor of the present invention has found that the presence or absence of fillet bleeding depends on the elapsed time from the plasma treatment of the substrate to the formation of the underfill material. Furthermore, when the changes in plasma processing and subsequent time passage were examined, it was found that the critical surface tension of the substrate was greatly changed.

From the above, the inventors of the present invention established the following relationship in view of the fact that the critical surface tension correlates with the bleed of the fillet and, as described above, the contamination of the fillet is caused by the separation of the filler and the binder. It has been found that the contamination of the fillet can be prevented.

(Surface tension of dispersant)> (Critical surface tension of substrate)
Since the dispersant has a function of stabilizing the dispersion of the filler and the binder, when the dispersant is easily wetted to the substrate, a part of the dispersant flows out onto the substrate widely. It becomes stable and it is considered that the filler and the binder are separated. In general, when the surface tension of the liquid is larger than the critical surface tension of the solid, the liquid is difficult to get wet with the solid.

In addition, the reason why the generation of fillet bleeding depends on the elapsed time from the plasma treatment of the substrate to the formation of the underfill material is that the critical surface tension of the surface of the substrate has decreased with the elapsed time. Since the critical surface tension of the substrate is lower than the surface tension of the dispersant, bleed occurs in the fillet of the underfill formed immediately after the plasma treatment, and the underfill formed after a certain time has elapsed since the plasma treatment. It is thought that the phenomenon that bleed does not occur appears in the fillet.

For the above reasons, if the condition that the critical surface tension of the dispersant is larger than the critical surface tension of the surface in contact with the underfill material in the first substrate or the second substrate, bleed occurs in the fillet of the underfill. It becomes difficult to do. It is preferable that the surface tension of the dispersant is larger than the critical surface tension of any of the surface in contact with the underfill material in the first substrate and the surface in contact with the underfill material in the second substrate.

The critical surface tension can be determined with reference to Japanese Patent Application Laid-Open No. 2010-164980. The critical surface tension is a physical property known as “wetting property” of the surface physical property of the polymer, and is the surface tension (γc) of the solid. Since this γc cannot be directly evaluated like a liquid, it can be obtained from the Young-Dupre equation and Zisman Plot as follows.
Young-Dupre equation:
γLV cos θ = γSV−γSL
In the formula, θ: contact angle, S: solid, L: liquid, V: saturated vapor. When water is used as the liquid, θ is 90 °, and when θ is 90 ° or more, the surface is hydrophobic, and the surface close to 0 ° is called hydrophilic.
Zisman Plot:
The contact angle θ is measured using various liquids having a surface tension γLV, and γLV and cos θ are plotted. When γLV approaches γSV on the solid surface, θ decreases, and the contact angle θ becomes 0 ° at a certain value of γLV. The γLV of the liquid when θ = 0 ° is defined as the surface tension of the solid, that is, the critical surface tension (γc).

Dispersants include amino group-containing block copolymers, acid group-containing polymers, hyperbranched amino group-containing polyesters, cationic group-containing acrylic polymers, carboxyl group-containing polymer modified products, polycarboxylic acid ester-containing polyaminoamide salts, nitrogen-containing grafts Polymer, High molecular fatty acid derivative, Phosphoric acid derivative of organic modified polymer, Modified polyester, Urethane polymer, Polyesteramine salt, Long chain amine salt of polycarboxylic acid, Polyphosphate ester, Basic functional group-containing copolymer, Modified polyvinyl alcohol And so on. The dispersant is selected according to the first substrate and the second substrate to be used so that the above conditions are satisfied.

From the viewpoint that the above conditions are easily satisfied, the surface tension of the dispersant is preferably 10 to 70 mN / m, more preferably 20 to 65 mN / m, and more preferably 30 to 60 mN / m. Further preferred.

Further, from the viewpoint that the above condition is easily satisfied, the critical surface tension of the surface in contact with the underfill material in the first substrate and the second substrate is preferably less than 50 mN / m, and less than 45 N / m. It is more preferable. The numerical value of the critical surface tension is a numerical value after the pretreatment when a pretreatment such as a plasma treatment is performed, and an underfill is applied when the critical surface tension changes with time after the pretreatment. It is a numerical value at the time of applying the material forming adhesive.

Furthermore, it is preferable that the critical surface tension of the inorganic particles is larger than the surface tension of the dispersant because separation of the filler and the binder can be suppressed and the fouling of the fillet can be prevented. The critical surface tension of the inorganic particles is preferably 70 mN / m or more, and more preferably 75 N / m or more.

The content of the dispersant is usually 0.1 to 5% by mass in the adhesive for forming the underfill material.
The underfill material-forming adhesive preferably contains an epoxy resin as a binder.

The epoxy resin may be a low molecule or a polymer as long as it has one or more epoxy groups in the molecule. Among these, low molecules are preferable because generation of voids in the adhesive layer can be satisfactorily suppressed.

The epoxy resin preferably has two or more epoxy groups in the molecule because the semiconductor element can be satisfactorily bonded. Examples of the epoxy resin include the same compounds as the “compound having two or more epoxy groups” mentioned in the description of the aromatic secondary amine described later. Among these compounds, there are 3 epoxy groups such as a compound having 3 epoxy groups having no aromatic ring, a compound having 3 epoxy groups having an aromatic ring, and a compound having 4 or more epoxy groups. A compound having two or more compounds is preferable because it can form a three-dimensional network structure by reaction with an aromatic secondary amine described later, and can satisfactorily bond a semiconductor element.
The content of the binder is usually 20 to 80% by mass in the adhesive for forming the underfill material.

It is preferable that the adhesive for forming the underfill material further contains a curing agent in addition to the binder, the inorganic particles, and the dispersant. Since an epoxy resin is included as a binder, an amine is usually used as a curing agent. Examples of the amine include aliphatic primary to tertiary amines and aromatic primary to tertiary amines, and among these, aromatic primary amines and aromatic secondary amines are preferable.

The aromatic secondary amine can be obtained, for example, by reacting an aromatic primary amine with a compound having two or more epoxy groups.
Examples of the aromatic primary amine include aniline, 1-naphthylamine, 2-naphthylamine, 2-aminophenol, 3-aminophenol, 4-aminophenol, 4-amino-3-methylphenol, and 2-amino-4. -Methylphenol, 3-amino-2-methylphenol, 5-amino-2-methylphenol, 1-amino-2-naphthol, 3-amino-2-naphthol, 2- (4-aminophenyl) -6-amino Monoamines such as benzoxazole and 5-amino-1-naphthol;
o-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 2,4-diaminoanisole, 2,4-toluenediamine, 4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4 '-Diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4′-bis (4-aminophenoxy) biphenyl, 2,2-bis {4- (4-aminophenoxy) phenyl} propane, 2,2-bis {4- (4 -Aminophenoxy) phenyl} hexafluoropropane, bis {4- (4-aminophenoxy) phenyl} sulfo Bis {4- (3-aminophenoxy) phenyl} sulfone, 4,4′-diamino-2,2′-bis (trifluoromethyl) diphenyl ether, bis {4- (4-aminophenoxy) phenyl} ketone, , 4-bis (4-aminophenoxy) -2,3,5-trimethylbenzene, 1,4-bis (4-aminophenoxy) -2,5-di-t-butylbenzene, 1,4-bis {4 -Amino-2- (trifluoromethyl) phenoxy} benzene, 4,4'-diamino-2- (trifluoromethyl) diphenyl ether, 2,3'-diaminodiphenyl ether, bis (4-aminophenoxy) methane, 1,3 -Bis (4-aminophenoxy) propane, 1,4-bis (4-aminophenoxy) butane, 1,5-bis (4-aminophenoxy) penta 1,3-bis (4-aminophenoxy) neopentane, 2,5-bis (4-aminophenoxy) -biphenyl, 4,4′-diamino-3,3′-dimethylbiphenyl, 4,4′-diamino- 2,2′-dimethylbiphenyl, 4,4′-diamino-2,2′-dimethoxybiphenyl, 4,4′-diamino-2,2′-bis (trifluoromethyl) biphenyl, 3,7-diamino-2 , 8-Dimethyldibenzothiophene 5,5-dioxide, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-diamino-3,3′-dihydroxybiphenyl, 4,4′-bis (4- Aminobenzamide) -3,3′-dihydroxybiphenyl, 2,2-bis (3-amino-4-hydroxyphenyl) propane, 9,9-bis (4-aminophenyl) fluorene, 3, 3 ′, 4,4′-tetraaminodiphenyl ketone, 4,4′-diaminodiphenyl ketone, bis {4- (4-aminophenoxy) phenyl} ketone, 2,2-bis {4- (4-aminophenoxy) Phenyl} hexafluoropropane, 2,2-bis {4- (4-aminophenoxy) phenyl} propane, 2,2-bis (3-amino-4-hydroxyphenyl) sulfone, 4,4′-diaminodiphenyl sulfide, N- (4-aminophenyl) -4-aminobenzamide, N, N′-bis (4-aminophenyl) terephthalamide, N, N′-bis (4-aminophenyl) piperazine, trimethyleneoxybis-4- Diamines such as aminobenzoate and polytetramethyleneoxybis-4-aminobenzoate;
4,4 ', 4 "-triaminotriphenylmethane, 2,3,6-pyridinetriamine, 2,4,6-pyridinetriamine, 2,4,5-pyrimidinetriamine, 2,4,6-

triaminotoluene

1,2,3-benzenetriamine, 1,3,5-benzenetriamine, 2,4,4′-triaminodiphenyl ether, 3,3 ′, 4,4′-tetraaminodiphenyl ether, melamine, and 3,3 And polyvalent amines such as', 4,4'-tetraaminodiphenylsulfone;

Examples of the compound having two or more epoxy groups include a compound having two epoxy groups, a compound having three epoxy groups, and a compound having four or more epoxy groups.

Examples of the compound having two epoxy groups include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, epoxypropoxypropyl-terminated poly Dimethylsiloxane, neopentyl glycol diglycidyl ether, glycerol diglycidyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, polypropylene glycol diglycidyl ether having a molecular weight of 2000 or less, and polyethylene glycol diglycidyl having a molecular weight of 2000 or less Compounds having two epoxy groups having no aromatic ring, such as ether;
Epicoat 827, Epicoat 828, Epicoat 834 (Mitsubishi Chemical Co., Ltd.), EPICLON 840, EPICLON 850, EXA-850CRP (Made by DIC) BPO-20E, BPO-60E (Nippon Nippon Rika Co., Ltd.), Epicoat Commercially available bisphenols such as 806, Epicoat 807 (above, manufactured by Mitsubishi Chemical), EPICLON 830, EPICLON 830-S, EPICLON 835, EPICLON EXA-83CRP, EPICLON EXA-830LVP, and EPICLON EXA-835LV (above, made by DIC) Type epoxy resin, 2,7-naphthalenediglycidyl ether, 2,6-naphthalenediglycidyl ether and other compounds having two epoxy groups having an aromatic ring; It is.

Examples of the compound having three epoxy groups include compounds having three epoxy groups having no aromatic ring, such as trimethylolpropane triglycidyl ether and glycerol triglycidyl ether;
Tetraglycidyl-3,4'-diaminodiphenyl ether, tetraglycidyl-3,3'-diaminodiphenyl ether, tetraglycidyl-3,4'-diamino-2,2'-dimethyldiphenyl ether, tetraglycidyl-4,4'-diaminodiphenyl ether 3 epoxy groups having an aromatic ring such as tetraglycidyl-3,4'-diamino-5-methyldiphenylmethane, tetraglycidyl-3,4'-diamino-2'-methyldiphenylmethane and triglycidyl-m-aminophenol And the like.

Examples of the compound having 4 or more epoxy groups include compounds having 4 or more epoxy groups such as trimethylolpropane polyglycidyl ether having a molecular weight of 2000 or less and sorbitol polyglycidyl ether having a molecular weight of 2000 or less.

In the reaction of an aromatic primary amine and a compound having two or more epoxy groups, the equivalent ratio of the hydrogen of the amino group contained in the aromatic primary amine to the epoxy group contained in the compound having two epoxy groups (amine) (Hydrogen / epoxy group) is usually 2.0 or more, preferably 2 to 10. The reaction temperature is preferably 60 to 250 ° C., more preferably 80 to 180 ° C.

The amine content in the adhesive for forming an underfill material is preferably 0.5 to 1.5 mol, preferably 0.5 to 1.5 mol of amine hydrogen atoms with respect to 1 mol of epoxy groups contained in the epoxy resin. Is an amount of 0.7 to 1.3 mol.

In addition, the underfill material-forming adhesive may contain a diluent such as an organic solvent, a flux, a surfactant, an emulsifier, a low elastic agent, a diluent, an antifoaming agent, an ion trapping agent, and the like.

(Process (4))
In the step (4), the second substrate is stacked on the first substrate with the adhesive layer interposed therebetween, and the electrode pads of the first substrate and the electrode pads of the second substrate are interposed via the solder electrodes. The electrical connection structure is formed.

For example, as shown in FIG. 1 (4-1), the first substrate having the solder electrode 6 produced in the step (2) on the second substrate 11 having the adhesive layer 7 produced in the step (3). Are arranged so that each electrode pad 12 of the second substrate 11 faces each solder electrode 6 of the first substrate 1.

FIG. 1 (4-2) shows the laminate 10 manufactured by the method for manufacturing a laminate of the present invention when the resist is not removed after the step (2). The laminated body 10 includes the electrode pads 2 of the first substrate 1 and the electrodes of the second substrate 11 via the solder electrodes 6 shown in FIGS. 1 (2) and (3) manufactured by the steps (1) to (3). It has an electrical connection structure formed by connecting the pad 12.

The electrode pad 12 of the second substrate 11 faces the electrode pad 2 of the first substrate 1 when the first substrate 1 and the second substrate 11 are opposed to each other with the surfaces on which the electrode pads are formed facing each other. In the position. The electrode pad 12 of the second substrate 11 is brought into contact with the adhesive layer 7 shown in FIG. 1 (3) and heated and / or pressurized. Then, the second substrate 11, the resist 5, and the solder electrode 6 are bonded together by the adhesive, and at the same time, the solder electrode 6 and the electrode pad 12 are soldered, and the adhesive layer 7 becomes the underfill material 13. In the underfill material 13, the portion protruding from the first substrate 1 is a fillet 14. Thereby, the electrode pad 2 of the 1st board | substrate 1 and the electrode pad 12 of the 2nd board | substrate 11 are electrically connected via the solder electrode 6, an electrical connection structure is formed, and the laminated body 10 is obtained. The heating temperature is usually 100 to 300 ° C., and the pressing force is usually 0.1 to 10 MPa.
Fillets are usually formed in the underfill material thus formed, but no fillet bleeding occurs as described above.

[Laminate]
The laminate of the present invention comprises an underfill material formed from the laminate produced by the method for producing a laminate, the first substrate, and the second substrate from the underfill material forming adhesive according to the present invention. It is the laminated body formed by laminating | stacking via.

[Electronic parts]
The electronic component of the present invention is an electronic component having the above-described laminate. Examples of the electronic component include a semiconductor element, a display element, and a power device.

EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples. In the following description of Examples and the like, “part” is used to mean “part by mass”.
1. Manufacture of adhesives for underfill formation

[Production Example] Production of Underfill Forming Adhesives 1 to 3 The components shown in Table 1 were mixed in the blending amounts shown in Table 1 using a rotation / revolution mixer, and then dispersed in a three-roll mill. The resulting dispersion is defoamed using a rotating / revolving mixer with a vacuum defoaming function, and then filled into a dispenser syringe to form an underfill adhesive 1-3 (hereinafter also referred to as adhesive 1-3). Manufactured. Details of each component in Table 1 are as described below.

Epoxy resin: Bisphenol A type epoxy resin (trade name “LX-01”, manufactured by Osaka Soda Co., Ltd.)
Curing agent: 4,4′-diaminodiphenylsulfone (trade name “Seika Cure S”, manufactured by Wakayama Seika Kogyo Co., Ltd.)
Inorganic particles: spherical silica (trade name “Sciquas 0.7 μm”, manufactured by Sakai Chemical Industry Co., Ltd.)
Dispersant A: Trade name “Disperbyk-2155” (manufactured by Big Chemie Japan Co., Ltd.)
Dispersant B: Trade name “Dispers685” (manufactured by Evonik Japan Co., Ltd.)
Dispersant C: Trade name “ED351” (manufactured by Enomoto Kasei Co., Ltd.)
Flux: 8-quinolinol (manufactured by Tokyo Chemical Industry Co., Ltd.)

2. Surface tension measurement [Substrate surface tension measurement]
Using a liquid mixture for wet tension test (manufactured by Wako Pure Chemical Industries, Ltd.) having a surface tension of 31.0, 39.0, 48.0, 61.0, 73.0 mN / m, respectively, The contact angle θ with respect to the substrate was measured. From the plot of cos θ against each surface tension (Zisman Plot), the surface tension at which cos θ = 1 was determined as the critical surface tension of the substrate.

[Surface tension measurement of dispersant]
The contact angle of the dispersant was measured on the substrate whose critical surface tension was clarified from the above method. The corresponding surface tension was read from the Zisman Plot of the substrate and used as the surface tension of the dispersant.

[Critical surface tension of inorganic particles]
It was confirmed from a reference (pigment dispersant in water-based paint, TECHNO-COSMOS 2007 Mar. Vol. 20).

In the following examples and comparative examples, “Example XY” and “Comparative Example XY” are indicated, but the number corresponding to X indicates the type of the underfill forming adhesive used. The number corresponding to Y is attached corresponding to the time from when the oxygen plasma treatment is applied until the adhesive for forming the underfill is applied onto the substrate II.
[Comparative Example 1-1]
According to FIG. 1, a laminate was produced by the IMS method described in Example 2 of WO2016 / 167036. Solder bumps were formed on the electrodes of the substrate I (first substrate 1) formed into a dicing chip. Next, an oxygen plasma treatment (oxygen pressure: 21 Pa, RF output: 200 W, 60 seconds) was performed as a pretreatment on the SiN substrate II having electrode pads. After applying the underfill-forming adhesive 1 manufactured in the manufacturing example using a dispenser on the substrate II immediately after the oxygen plasma treatment, the substrates are electrically connected via the solder bumps. 1 was placed. A pressure of 0.1 MPa was applied to both substrates at 250 ° C. for 20 seconds using a die bonder so that both substrates were bonded via an adhesive. Next, the adhesive was cured by heating in an oven at 170 ° C. for 2 hours to obtain a laminate.

The critical interface tension of the substrate II immediately after the oxygen plasma treatment was 48 mN / m. When the obtained laminate was evaluated for the presence or absence of fillet bleed by the following method, bleed was observed.

[Comparative Example 2-1]
A laminate was produced in the same manner as Comparative Example 1-1 except that the underfill forming adhesive 2 was used instead of the underfill forming adhesive 1. When the following method was used to evaluate the presence or absence of fillet bleeding, bleeding was observed.

[Comparative Example 3-1]
A laminate was produced in the same manner as Comparative Example 1-1 except that the underfill forming adhesive 3 was used instead of the underfill forming adhesive 1. When the following method was used to evaluate the presence or absence of fillet bleeding, bleeding was observed.

[Example 1-2]
A laminate was manufactured in the same manner as Comparative Example 1-1 except that the underfill-forming adhesive 1 was applied onto the substrate II after 17 hours had passed after the oxygen plasma treatment.
After 17 hours from the oxygen plasma treatment, the critical interface tension of the substrate II was 38 mN / m. When the obtained laminate was evaluated for the presence or absence of fillet bleed by the following method, no bleed was observed.

[Example 2-2]
A laminate was produced in the same manner as in Example 1-2 except that the underfill forming adhesive 2 was used instead of the underfill forming adhesive 1. When the following method was used to evaluate the presence or absence of fillet bleed, no bleed was observed.

[Comparative Example 3-2]
A laminate was produced in the same manner as in Example 1-2 except that the underfill forming adhesive 3 was used instead of the underfill forming adhesive 1. When the following method was used to evaluate the presence or absence of fillet bleeding, bleeding was observed.

[Example 1-3]
A laminate was manufactured in the same manner as Comparative Example 1-1 except that the underfill-forming adhesive 1 was applied onto the substrate II after 22 hours had passed after the oxygen plasma treatment.
The critical interfacial tension of the substrate II after 17 hours from the oxygen plasma treatment was 35 mN / m. When the obtained laminate was evaluated for the presence or absence of fillet bleed by the following method, no bleed was observed.

[Example 2-3]
A laminate was produced in the same manner as in Example 1-3 except that the underfill forming adhesive 2 was used instead of the underfill forming adhesive 1. When the following method was used to evaluate the presence or absence of fillet bleed, no bleed was observed.

[Comparative Example 3-3]
A laminate was produced in the same manner as in Example 1-3 except that the underfill forming adhesive 3 was used instead of the underfill forming adhesive 1. When the following method was used to evaluate the presence or absence of fillet bleeding, bleeding was observed.

[Example 1-4]
A laminate was manufactured in the same manner as Comparative Example 1-1 except that the underfill-forming adhesive 1 was applied onto the substrate II after 50 hours had passed after the oxygen plasma treatment.
The critical interfacial tension of the substrate II after 17 hours from the oxygen plasma treatment was 30 mN / m. When the obtained laminate was evaluated for the presence or absence of fillet bleed by the following method, no bleed was observed.

[Example 2-4]
A laminate was produced in the same manner as in Example 1-4, except that the underfill forming adhesive 2 was used instead of the underfill forming adhesive 1. When the following method was used to evaluate the presence or absence of fillet bleed, no bleed was observed.

[Example 3-4]
A laminate was produced in the same manner as in Example 1-4 except that the underfill forming adhesive 3 was used instead of the underfill forming adhesive 1. When the following method was used to evaluate the presence or absence of fillet bleed, no bleed was observed.

Evaluation of laminate [ Evaluation of fillet bleed]
The fillet blade was evaluated by observing the fillet of the laminate.
As shown in FIG. 2, the evaluation is performed by applying a uniform light to the measurement sample and observing the reflected light, and a dark field observation in which the sample is irradiated with light obliquely and the scattered light is observed. Went. In bright field observation, as shown by the arrow in the part surrounded by the broken line in the left diagram of FIG. Since no bleed image could be confirmed on the outside, it was assumed that the bleed does not contain an inorganic filler that scatters light, and the organic component is the main component. That is, bleed is considered to be caused by separation of the inorganic filler and the organic component.

[Time-dependent change of critical surface tension of SiN substrate after plasma treatment]
In the production of the laminate, when the critical surface tension of the SiN substrate II was measured, it was confirmed that the critical surface tension of the SiN substrate II was lowered according to the holding time from the oxygen plasma treatment. This phenomenon is thought to be due to the surface adhesion of trace amounts of organic substances in the atmosphere. FIG. 3 shows the change in the critical surface tension of the SiN substrate II with respect to the elapsed time from the oxygen plasma treatment.

[Relationship between fillet bleed and surface tension of substrate II, inorganic particles, and dispersant]
In the laminate, the elapsed time from the oxygen plasma treatment of the SiN substrate II and the presence or absence of bleed were evaluated. FIG. 4 is a diagram showing the relationship between the critical surface tension of the SiN substrate II, the surface tension of the dispersant, and the critical surface tension of the inorganic particles with or without bleeding of the laminate.

From the above evaluation of the presence or absence of bleed and FIG. 4, when there is a relationship of critical surface tension of inorganic particles> surface tension of dispersant> critical surface tension of substrate II, there is no bleed of fillet and a well-shaped fillet is formed. It was confirmed.

DESCRIPTION OF SYMBOLS 1 1st board |

substrates

2 and 12 Electrode pad 3 Coating film 4 Opening part 5 Resist 6 Solder electrode 7 Adhesive layer 8 IMS head 9 Molten solder 10 Laminated body 11 2nd board | substrate 13 Underfill material 14 Fillet

Claims

A method for manufacturing a laminate in which a second substrate having electrode pads is laminated on a first substrate having electrode pads via an underfill material,
Forming a resist having an opening corresponding to an electrode pad of the first substrate on the first substrate (1);
Forming a solder electrode on a portion of the first substrate corresponding to the opening (2);
On the solder electrode and / or on the second substrate,
Using an underfill material-forming adhesive containing inorganic particles and a dispersant having a surface tension larger than the critical surface tension of the surface in contact with the underfill material in the first substrate or the second substrate Forming the step (3), and laminating the second substrate on the first substrate across the adhesive layer, and via the solder electrodes, the electrode pads of the first substrate and the second substrate Step (4) of forming an electrical connection structure with the electrode pad
The manufacturing method of the laminated body which has this.
The method for producing a laminate according to claim 1, wherein the step (2) is a step (2 ') of filling the opening with molten solder while heating to form a solder electrode.
The manufacturing method of the laminated body of Claim 1 or 2 in which the said adhesive agent for underfill material formation contains an epoxy resin further.
The method for producing a laminate according to any one of claims 1 to 3, wherein the underfill material-forming adhesive further contains a curing agent.
The method for manufacturing a laminate according to any one of claims 1 to 4, wherein the first substrate or the second substrate is a plasma processing substrate.
The method for producing a laminate according to any one of claims 1 to 5, wherein a critical surface tension of the inorganic particles is larger than a surface tension of the dispersant.
The manufacturing method of the laminated body of Claim 6 whose critical surface tension of the said inorganic particle is 70 mN / m or more.
The method for producing a laminate according to any one of claims 1 to 7, wherein the dispersant has a surface tension of 10 to 70 mN / m.
The method for producing a laminate according to any one of claims 1 to 8, wherein a critical surface tension of a surface in contact with the underfill material in the first substrate and the second substrate is less than 45 mN / m.
A laminate produced by the laminate production method according to any one of claims 1 to 9.
An electronic component having the laminate according to claim 10.