JP4867181B2 - Thermosetting resin composition for mounting electronic components - Google Patents

Description

  The present invention relates to a thermosetting resin composition for mounting electronic components used when flip-chip mounting electronic components such as semiconductor chips on a circuit board, for example.

  In recent years, with the miniaturization and high performance of electronic devices, the size of packages has been reduced, and when mounting electronic components such as semiconductor elements on circuit boards, high-density mounting such as multi-pin and miniaturization has been achieved. It has been demanded. As a mounting technique for realizing these, area bump array type flip chip mounting such as CSP (Chip Size Package) and BGA (Ball Grid Array) is becoming mainstream.

  In conventional flip chip mounting, a solder bump made of a low melting point metal such as lead or tin or a low melting point metal alloy is formed on the mounting surface, and the solder bump is mounted using the self-alignment effect. . However, since this mounting method uses solder melting, various problems such as adjacent solder bumps are connected by melting due to fluidity in order to reduce the number of pins and pitch due to higher density mounting. There were problems such as solder bridges.

  In addition, as the solder becomes lead-free, melting of the solder requires a relatively high temperature, and there is a problem that thermal damage to the electronic component is likely to occur.

  Therefore, in recent years, pressure welding is being used as another mounting method that does not use solder melting. Examples of the pressure welding include a method of performing pressure bonding while heating and a method of applying ultrasonic waves during bonding.

  In addition, a method of mounting an electronic component on a circuit board using a resin adhesive made of a thermosetting resin is also performed. For example, in Patent Document 1 below, an element electrode and a circuit electrode are bonded via a thermosetting conductive adhesive containing metal particles and a thermosetting resin, and an electronic component is mounted on a circuit board.

  In Patent Document 2 below, a resin film having adhesiveness is disposed on a circuit board, and an element electrode of an electronic component and a circuit electrode of the circuit board are joined via the resin film, and the surface of the electronic component and the circuit board are bonded. An insulating resin is applied and cured so as to cover the surface of the substrate and the surface of the resin film, and the electronic component is mounted on the circuit board.

  In the following Patent Document 3, an exothermic peak at a continuous temperature rising scanning speed of 10 K / min in differential scanning calorimetry is measured between a device electrode and a circuit through a thermosetting resin composition having a specific composition at a temperature from 453 K to 523 K. Electrodes are joined and electronic components are mounted on the circuit board.

In the following Patent Document 4, when the element electrode on the surface of the electronic component and the circuit electrode on the circuit board are bonded via the thermosetting resin, the reaction rate of the thermosetting resin composition immediately after the bonding-curing process is 40%. When the reaction rate is 40% or less, the element electrode and the circuit electrode are cured by curing the thermosetting resin composition including a step of post-curing at a temperature below the solder melting point. The electronic components are mounted on the circuit board.
JP 2000-251536 A JP 2001-35884 A JP 2003-171535 A JP 2003-289089 A

  In the mounting method of the electronic component using the resin adhesive containing the thermosetting resin, there are problems in high temperature characteristics and thermal fatigue life, and there is a problem that sufficient reliability of the joint portion cannot be obtained. In other words, the mounting method of the electronic component using the resin adhesive is to cure the thermosetting resin to join the element electrode of the electronic component and the circuit electrode of the circuit board, but the rapid heating / curing of the thermosetting resin. This is because the residual stress in the cured product increases, fine microcracks are generated in the resin cured product or the element electrode of the electronic component, and the reliability of the electronic component may be reduced. Even with the resin compositions of Patent Documents 1 to 3, the reliability of bonding was not sufficient.

  In addition, by controlling the curing reaction rate of the resin composition as in Patent Document 4, it is possible to make microcracks less likely to occur, but the reaction rate may vary depending on the resin composition, and the quality is stable. I did not. Moreover, since it is necessary to manage the reaction rate of a resin composition suitably, manufacturing cost and manufacturing time were also required.

  Accordingly, an object of the present invention is to provide a high reliability of bonding between an electrode of an electronic component and an electrode on a circuit board, and to secure an insulation reliability between adjacent electrodes, and circuit the electrode of the electronic component at a low cost. It is providing the thermosetting resin composition for electronic component mounting which can be connected to a board | substrate.

To solve the above problems, in the electronic component mounting thermosetting resin composition used for bonding the electrodes of the electronic component and the circuit board electrodes, and the inorganic insulating material comprises an aerosol-like particles having an average particle diameter 1nm~1μm And an electroconductive filler having an average particle diameter of 100 μm or less, and an exothermic peak at a continuous heating rate of 10 K / min in the differential scanning calorimetry of the thermosetting resin composition for mounting electronic components has a temperature from 373 K to 523 K. And the viscosity at a temperature of 298 K when the resin composition is uncured is 0.5 to 100 Pa · s.

  In a thermosetting resin composition having two or more exothermic peaks in differential scanning calorimetry, since the curing reaction by heating proceeds in multiple stages, the curing reaction proceeds slowly. Accordingly, rapid thermal curing can be prevented, and stress remaining in the cured product of the resin composition can be reduced.

  Therefore, an electronic component is mounted on a circuit board with a thermosetting resin composition having at least two exothermic peaks at a temperature rising scanning speed of 10 K / min in differential scanning calorimetry in a temperature range of 373 K to 523 K. When used at the time, cracks such as microcracks are unlikely to occur in the cured resin composition, so that the reliability of bonding between the element electrode of the electronic component and the circuit electrode of the circuit board is high.

  In addition, by controlling the viscosity of the uncured product to a viscosity of 0.5 to 100 Pa · s at a temperature of 298 K, the sedimentation rate of the conductive filler is delayed in blending the conductive filler particles with the thermosetting resin liquid. It can be expected that the non-uniform mixing of the resin liquid can be suppressed, and that the thermosetting resin liquid can be prevented from flowing out when applied on the circuit board.

Furthermore, in the present invention, the thermosetting resin composition for mounting an electronic component preferably has a volume content of the conductive filler of 5 to 90% with respect to the entire thermosetting resin composition for mounting an electronic component. . And it is preferable that the volume content rate of the said inorganic insulating material with respect to the said thermosetting resin composition for electronic component mounting is 0.1%-90%.

According to the present invention, an inorganic insulating material containing aerosol fine particles having an average particle diameter of 1 nm to 1 μm and a conductive filler having an average particle diameter of 100 μm or less are contained, and a continuous temperature rising scanning speed in differential scanning calorimetry is 10 K / min. The thermosetting resin composition having at least two exothermic peaks in the temperature range of 373 K to 523 K and having an uncured viscosity of 0.5 to 100 Pa · s is obtained by using an element electrode and a circuit of an electronic component. By using it when joining the circuit electrodes of the substrate, it is possible to increase the reliability of bonding between the element electrode of the electronic component and the circuit electrode of the circuit substrate, and to ensure the insulation reliability between the adjacent electrodes, An electronic component can be mounted on a circuit board by an easy method and at low cost.

  The thermosetting resin composition for electronic parts of the present invention has at least two exothermic peaks at a temperature rising scanning speed of 10 K / min in differential scanning calorimetry in the temperature range of 373 K to 523 K, and The viscosity at a temperature of 298K during curing is 0.5 to 100 Pa · s. Such a resin composition can be prepared by appropriately blending a curing agent or a curing catalyst with a thermosetting resin, and is not limited to a specific composition.

  As a universal technique for evaluating the thermosetting property of a resin, there is a differential scanning calorimetry (DSC), and this DSC is an evaluation method for measuring a change in calorie. The chemical reaction during polymerization and curing of the thermosetting resin is an exothermic reaction, and this thermal change can be measured using DSC in relation to the range of chemical reaction. And, for example, as described by Hadad in “Epoxy Resin. Chemistry and Technology”, May edition, Marcel Decker, 1988, page 1130, the amount of energy released during the curing reaction is proportional to the degree of the chemical reaction. The hypothesis is to be made.

  The thermosetting resin that can be used in the present invention is not particularly limited. For example, epoxy resin, urethane resin, acrylic resin, silicone resin, phenol resin, melamine resin, alkyd resin, urea resin, acrylic resin Resin, unsaturated polyester resin and the like, and these can be used alone, blended or copolymerized.

  Of the above thermosetting resins, epoxy resins are particularly preferable. Specific examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD type epoxy resins, naphthalene type epoxy resins, and biphenyl type epoxy resins. , Glycidylamine type epoxy resins, alicyclic epoxy resins, dicyclopentadiene type epoxy resins, phenol novolac type epoxy resins, polyester modified epoxy resins, copolymers with other polymers such as silicone modified epoxy resins, etc. . Among these, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, naphthalene type epoxy resin, phenol novolac type epoxy resin, etc. have a relatively low viscosity and excellent heat resistance and moisture resistance. It is particularly preferable in view of the above.

  When an epoxy resin is used, a reactive diluent having an epoxy group in the molecular structure may be further added. Examples of reactive diluents include tert-butylphenyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 1 Monoglycidyl compounds such as-(3-glycidoxypropyl) 1,1,3,3,3-pentamethyldisiloxane, N-glycidyl-N, N, -bis [3- (trimethoxysilyl) propyl] amine And monoalicyclic epoxy compounds such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane.

  In addition to the reactive diluent, the epoxy compound shown below may be added to the epoxy resin. Examples of such an epoxy compound include resorcin diglycidyl ether, hydroquinone diglycidyl ether, 2,5-di-tert-butylhydroquinone diglycidyl ether, butanediol diglycidyl ether, butenediol diglycidyl ether, butynediol diglycidyl ether, Alkylene glycidyl ethers such as glycerin triglycidyl ether, trimeterolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1,3-diglycidyl-5,5-dialkylhydantoin, 1-glycidyl-3- (glycidoxyalkyl) -5 , 5-Dialkylhydantoins and other glycidyl group-containing hydantoin compounds, diglycidyl phthalate, diglycidyl tetrahydrophthalate, dimer Glycidyl esters such as diglycidyl ester, tetraglycidyl diaminodiphenyl ester, triglycidyl-p-aminophenylmethane, triglycidyl-m-aminophenylmethane, diglycidylaniline, diglycidyltoluidine, tetraglycidyl-m-xylylenediamine, etc. Glycidyl group-containing amino compounds, 1,3-bis (3-glycidoxypropyl) -1,1,3,3-tetramethyldisiloxane, α, β-bis (3-glycidoxypropyl) polydimethylsiloxane, etc. Glycidyl group-containing siloxane, imidazole compound and the like.

  The thermosetting resin composition for mounting electronic components of the present invention is, for example, 3,5-diethyl-based on 100 parts by mass of a bisphenol F type epoxy resin (epoxy equivalent 162 manufactured by Dainippon Ink and Chemicals, Inc.). Examples include 10 parts by mass of 2,6-toluenediamine and 3 parts by weight of 2-phenylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd.), which are prepared by mixing and dispersing uniformly. Is not to be done.

  Moreover, in order to adjust the linear expansion coefficient of a conductive filler and a resin layer, you may further add the inorganic insulating material to the thermosetting resin composition for electronic component mounting of this invention.

  Examples of the material of the conductive filler include Ag, Sn, Cu, Bi, In, Al, Au, Zn, and binary alloys or ternary alloys thereof, and among them, Sn—In and Sn—Bi are preferable.

  The average particle diameter of the conductive filler is preferably 100 μm or less, more preferably 10 to 80 μm, and still more preferably 20 to 50 μm. When the average particle size is 100 μm or more, the viscosity of the resin composition increases, and for example, when a resin liquid is supplied onto an electronic component by a dispenser or the like, liquid clogging occurs or a conductive pattern corresponding to a fine pitch cannot be formed. There is a fear.

  The blending amount of the conductive filler is preferably blended so that the volume content of the conductive filler in the entire thermosetting resin composition for mounting electronic components is 5 to 90%, more preferably 10 to 50%. is there. When the volume content of the conductive filler in the resin composition for mounting an electronic component is 90% or more, there is a possibility that liquid clogging may occur when the resin liquid is supplied onto the electronic component.

  Examples of the material of the inorganic insulating material include fused silica powder, quartz glass powder, glass fiber, talc, alumina powder, carbon black, and carbon nanotube, and are preferably used as aerosol-like fine particles. Here, the aerosol fine particles mean fine particles having an average particle diameter of about 1 nm to 1 μm.

  By compounding an aerosol-like inorganic insulating material, the linear expansion coefficient of the entire resin cured product can be brought close to the linear expansion coefficient of silicon and copper used in electronic components, and heat caused by expansion / contraction of mounted components The stress can be reduced, and at the same time, an effect can be obtained for adjusting the viscosity increase of the resin liquid.

The aerosol-like inorganic insulating material is, for example, an average particle diameter of primary particles produced by oxidizing and hydrolyzing SiCl ₄ gas with a flame of 1100 to 1400 ° C. in which a mixed gas of H ₂ and O ₂ is burned. Is a spherical ultrafine particle mainly composed of amorphous silicon dioxide having a size of about 5 to 50 nm, and primary particles having an average particle size in the range of 5 to 50 nm are aggregated, and the particle size is several to 1 μm. Examples include secondary particles formed, and are not particularly limited in application.

  The blending amount of the inorganic insulating material is preferably blended so that the volume content of the inorganic insulating material in the entire thermosetting resin composition for mounting electronic components is 0.1% or more, more preferably 1 to 1. 20%. If the volume content of the inorganic insulating material in the resin composition for mounting electronic components is less than 0.1%, the effect of adjusting the viscosity increase and the coefficient of thermal expansion of the entire resin cured product is expected. There is a possibility that it cannot be done.

  Further, in the thermosetting resin composition for mounting electronic parts of the present invention, an antifoaming agent, a leveling agent or the like may be used for improving smoothness.

  Examples of antifoaming agents include silicone compounds. Examples of the leveling agent include fluorine oil and silicone oil.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, this invention is not limited to a following example.

(Test Example 1)
To 100 parts by mass of the epoxy resin represented by the following formula (1), 5 parts by mass of the compound of the following formula (2) and 3 parts by weight of 2-methylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd.) are added uniformly. It mixed until it became, and the thermosetting resin composition A was obtained. This was used as a thermosetting resin composition 1 for mounting electronic components.

  Next, this thermosetting resin composition 1 for mounting electronic components is cast on a clean quartz substrate with a thickness of 1 mm, and Ni / Au plating is applied to copper foil / polyimide (= 12/25 μm) as an adherend. It was sandwiched between substrates with Then, after heating to 393K at a temperature increase rate of 20 K / min, holding the temperature at 393 K for 30 minutes, further heating to 453 K at a temperature increase rate of 20 K / min, holding at a temperature of 453 K for 60 minutes, A specimen 1 was obtained.

(Test Example 2)
To the thermosetting resin composition A of Test Example 1, Ag particles having an average particle size of 50 μm were added as a conductive filler so that the volume content in the entire thermosetting resin composition for mounting electronic components was 5 %. A test body 2 was obtained in the same manner as in Test Example 1 except that the obtained thermosetting resin composition 2 for mounting electronic components was used.

(Test Example 3)
To the thermosetting resin composition A of Test Example 1, Ag particles having an average particle diameter of 50 μm were added as a conductive filler so that the volume content in the entire thermosetting resin composition for mounting electronic components was 70%. A test body 3 was obtained in the same manner as in Test Example 1 except that the obtained thermosetting resin composition 3 for mounting electronic components was used.

(Test Example 4)
To the thermosetting resin composition A of Test Example 1, Sn—In particles having an average particle diameter of 50 μm are added as a conductive filler so that the volume content in the entire thermosetting resin composition for mounting electronic components is 70%. A test body 4 was obtained in the same manner as in Test Example 1 except that the thermosetting resin composition 4 for mounting electronic components obtained in this way was used.

(Test Example 5)
Addition of Sn-Bi particles having an average particle size of 50 μm as a conductive filler to the thermosetting resin composition A of Test Example 1 so that the volume content in the entire thermosetting resin composition for mounting electronic components is 70%. A test body 5 was obtained in the same manner as in Test Example 1 except that the thermosetting resin composition 5 for mounting electronic components obtained in this way was used.

(Test Example 6)
In the thermosetting resin composition A of Test Example 1, Sn—Ag—Cu particles having an average particle diameter of 50 μm as conductive fillers are 70% in volume in the entire thermosetting resin composition for mounting electronic components. A test body 6 was obtained in the same manner as in Test Example 1 except that the thermosetting resin composition 6 for mounting an electronic component obtained by adding to was used.

(Test Example 7)
The aerosol content (spherical fused silica) with an average particle size of 0.1 μm is added to the thermosetting resin composition A of Test Example 1 so that the volume content of the entire thermosetting resin composition for mounting electronic components is 0.1%. A test body 7 was obtained in the same manner as in Test Example 1 except that the thermosetting resin composition 7 for mounting an electronic component obtained by adding to was used.

(Test Example 8)
To the thermosetting resin composition A of Test Example 1, Sn—In particles having an average particle diameter of 50 μm are added as a conductive filler so that the volume content in the entire thermosetting resin composition for mounting electronic components is 70%. In addition, electrons obtained by adding aerosol fine particles (spherical fused silica) with an average particle size of 0.1 μm so that the volume content in the entire thermosetting resin composition for mounting electronic components is 0.1%. A test body 8 was obtained in the same manner as in Test Example 1, except that the component mounting thermosetting resin composition 8 was used.

(Test Example 9)
To the thermosetting resin composition A of Test Example 1, Ag particles having an average particle size of 50 μm were added as a conductive filler so that the volume content in the entire thermosetting resin composition for mounting electronic components was 95%. A test body 9 was obtained in the same manner as in Test Example 1 except that the obtained thermosetting resin composition 9 for mounting electronic components was used.

(Test Example 10)
Bisphenol F-type epoxy resin (epoxy equivalent 162, manufactured by Dainippon Ink & Chemicals, Inc.) with respect to 100 parts by mass, 10 parts by mass of 3,5-diethyl-2,6-toluenediamine, and 2-phenylimidazole (Shikoku) The same as in Test Example 1, except that 3 parts by weight of Kasei Kogyo Co., Ltd.) was added and mixed, and the thermosetting resin composition B uniformly dispersed was used as the thermosetting resin composition 10 for mounting electronic components. Thus, a test body 10 was obtained.

(Test Example 11)
In the thermosetting resin composition B of Test Example 10, Sn—In eutectic spherical particles having an average particle diameter of 50 μm as the conductive filler are 70% in the entire thermosetting resin composition for mounting electronic components. A test body 11 was obtained in the same manner as in Test Example 1 except that the thermosetting resin composition 11 for mounting an electronic component obtained by adding as described above was used.

<Evaluation items>
[Physical properties of the resin composition]
(Differential scanning calorimetry)
“DSC-6200” (manufactured by Seiko Instruments Inc.) as a differential scanning calorimeter, electronic component mounting heat under conditions of continuous temperature rising scanning rate from room temperature of 10 K / min, sample amount of 5 mg, nitrogen flow of 50 ml / min The exothermic peak of the curable resin composition was measured.

(Viscosity measurement)
Using an E-type viscometer, the viscosity of the thermosetting resin composition for mounting electronic components at 25 ° C. immediately after the preparation of the thermosetting resin composition for mounting electronic components was measured at 5 rpm.

[Evaluation of specimen]
(Crack property)
The specimen was put into a constant temperature and humidity test (85 ° C. and 85% RH), and the cross-section was observed after 500 hours, and the presence or absence of cracks in the resin composition was investigated.

  The said evaluation was performed about the thermosetting resin compositions 1-11 for electronic component mounting, and the test bodies 1-11. The exothermic peaks of the thermosetting resin compositions 1 and 10 for mounting electronic components are shown in FIG. Moreover, the exothermic peak and viscosity of the thermosetting resin compositions 1 to 11 for mounting electronic components and the results of the crack property test of the test bodies 1 to 11 are collectively shown in Table 1.

  From the above results, the thermosetting resin for mounting electronic components has two or more exothermic peaks of the thermosetting resin composition in the temperature range of 373K to 523K, and the viscosity at the temperature of 298K is 0.5 to 100 Pa · s. In the test bodies 1 to 8 using the compositions 1 to 8, good results were obtained in the cracking test, and good results were obtained with the reliability of bonding.

  On the other hand, the test piece 9 using the thermosetting resin composition 9 for mounting electronic components whose viscosity at a temperature of 298K of the thermosetting resin composition is 100 Pa · s or more, the exothermic peak is 1 in the temperature range of 373K to 523K. The test bodies 10 and 11 using the thermosetting resin compositions 10 and 11 for mounting an electronic component, which have only one, are prone to cracks in the crack property test, and cannot sufficiently maintain the bonding reliability.

  The thermosetting resin composition for mounting an electronic component of the present invention can be suitably used, for example, when flip-chip mounting an electronic component such as a semiconductor chip on a circuit board.

It is a graph which shows the exothermic peak of the thermosetting resin composition for electronic component mounting.

Claims (3)

In the thermosetting resin composition for electronic component mounting used for joining the electrode of the electronic component and the electrode of the circuit board,
An inorganic insulating material containing aerosol fine particles having an average particle size of 1 nm to 1 μm, and a conductive filler having an average particle size of 100 μm or less ,
There are at least two exothermic peaks at a temperature rising scanning speed of 10 K / min in the differential scanning calorimetry of the thermosetting resin composition for mounting an electronic component in the temperature range of 373 K to 523 K, and the resin composition A thermosetting resin composition for mounting electronic components, wherein the viscosity at an uncured temperature of 298K is 0.5 to 100 Pa · s.   The thermosetting resin composition for mounting electronic components according to claim 1, wherein a volume content of the inorganic insulating material with respect to the entire thermosetting resin composition for mounting electronic components is 0.1% to 90%. The thermosetting resin composition for mounting an electronic component according to claim 1 or 2, wherein a volume content of the conductive filler with respect to the entire thermosetting resin composition for mounting the electronic component is 5 to 90%.