JP2017028067A - Connection method of circuit member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection method of a circuit member capable of efficiently and firmly connecting circuit members with each other while preventing the resin layer from remaining between the terminals.SOLUTION: The connection method of the circuit member of the present invention includes a preparing step of preparing a mounting substrate 1 (a first circuit member), a semiconductor element 2 (a second circuit member), a bump electrode 30 (a connection metal), and a resin layer 4, a mounting step of pressing the semiconductor element 2 and the mounting substrate 1 together while heating the bump electrode 30 to a temperature lower than its melting point Tm, and a heating step of heating the bump electrode 30 to Tm-70°C or more and Tm + 200°C or less. The resin layer 4 has a flux function. When the minimum melt viscosity measured at 1 Hz is 10 to 10,000 Pa s and the viscosity at 1 Hz at 180°C is η[Pa s], and the viscosity at 10 Hz is η[Pa s], η/ηis 3 to 25.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for connecting circuit members.

  In recent years, miniaturization, weight reduction, and high performance of electronic devices have been demanded, and in multilayer printed wiring boards, miniaturization and high density of wiring are progressing. Along with this, there is an increasing demand for thinning and miniaturization of a structure for mounting a semiconductor chip on a mounting substrate.

  Therefore, as a method of mounting the semiconductor chip on the mounting substrate, a large number of bump electrodes are formed on the surface of the semiconductor chip electrode, and the chip-side electrode and the substrate-side electrode are electrically connected via the bump electrode. Flip chip mounting to connect to is popular. According to such flip-chip mounting, it is possible to easily realize a multi-pin and downsized connection structure.

  Patent Document 1 discloses manufacturing a semiconductor device by connecting a semiconductor chip to a mounting substrate via bump electrodes (solder bumps).

  In addition, an adhesive that covers the mounting surface is attached to the mounting substrate before the connection, and the semiconductor chip is heated with respect to the mounting substrate through the adhesive during the connection. Pressurize. As a result, the electrode on the semiconductor chip side and the electrode on the mounting substrate side are electrically connected, and excess adhesive protrudes outside the semiconductor chip.

JP 2001-332583 A

  By the way, in the connection method described in Patent Document 1, if an adhesive remains between the solder bump and the connection pad, it hinders electrical connection. For this reason, by temporarily connecting the solder bump and the connection pad in a state where the adhesive is not cured, the adhesive is prevented from remaining between the solder bump and the connection pad.

  However, in order to prevent the adhesive from remaining between the solder bump and the connection pad, it is necessary to give the adhesive an appropriate fluidity. With difficulty.

  The objective of this invention is providing the connection method of the circuit member which can connect circuit members efficiently and firmly, preventing that a resin layer remains between terminals.

Such an object is achieved by the present inventions (1) to (6) below.
(1) a first circuit member comprising a first surface and a first terminal provided on the first surface side;
A second circuit member comprising: a second surface; and a second terminal provided on the second surface side;
A connection metal having a melting point Tm [° C.] provided on at least one of the first terminal and the second terminal;
It is provided on at least one of the first surface and the second surface, has a flux function, has a minimum melt viscosity of 10 to 10,000 Pa · s when measured at 1 Hz, and a viscosity at 1 ° C. at 180 ° C. ₁ [Pa · s], and a viscosity at η ₁₀ [Pa · s] at ₁₀ Hz, a resin layer having a viscosity ratio η ₁ / η ₁₀ of 3 to 25;
A preparation process to prepare,
A mounting step of pressing the first terminal and the second terminal through the connection metal and the resin layer while heating the connection metal to a temperature lower than Tm;
A heating step of heating the connecting metal that has undergone the mounting step to Tm-70 ° C. or higher and Tm + 200 ° C. or lower;
A circuit member connection method comprising:

(2) In the mounting step, the first terminal and the second terminal are pressed against each other for 0.1 to 60 seconds with a load of 0.5 to 10 gf per connection electrode. Circuit member connection method.

(3) In the mounting step, the circuit member according to (1) or (2), wherein a maximum speed in a process in which the first terminal and the second terminal approach each other is 0.01 to 1 mm / second. Connection method.

(4) The method for connecting circuit members according to any one of (1) to (3), wherein the heating step cures the resin layer by heating the resin layer to a temperature lower than Tm.

(5) The circuit member connection method according to any one of (1) to (4), wherein at least one of the first circuit member and the second circuit member is a semiconductor component.

(6) The circuit member connection method according to any one of (1) to (5), wherein the connection metal includes Sn as a main component and Ag as a subcomponent.

  According to the present invention, the circuit members can be efficiently and firmly connected to each other while preventing the resin layer from remaining between the terminals. Thereby, highly reliable electrical connection can be achieved between the terminals.

It is sectional drawing for demonstrating embodiment of the connection method of the circuit member of this invention. It is sectional drawing for demonstrating embodiment of the connection method of the circuit member of this invention. It is sectional drawing for demonstrating embodiment of the connection method of the circuit member of this invention, Comprising: It is a figure which shows the example which arranges two semiconductor elements on a mounting board | substrate. It is sectional drawing for demonstrating embodiment of the connection method of the circuit member of this invention, Comprising: It is a figure which shows the example which laminates | stacks two semiconductor elements on a mounting substrate. It is sectional drawing for demonstrating the 1st modification of the connection method of the circuit member which concerns on embodiment. It is sectional drawing for demonstrating the 2nd modification of the connection method of the circuit member which concerns on embodiment. It is sectional drawing for demonstrating the 3rd modification of the connection method of the circuit member which concerns on embodiment.

  Hereinafter, the circuit member connection method of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

  1 and 2 are cross-sectional views for explaining an embodiment of a circuit member connecting method of the present invention. In the following description, for convenience of explanation, the upper part of FIGS.

  The circuit member connection method according to the present embodiment includes [1] a mounting substrate 1 (first circuit member), a semiconductor element 2 (second circuit member), a bump electrode 30 (connection metal), and a resin layer 4. A preparatory step, [2] a mounting step of pressing the semiconductor element 2 and the mounting substrate 1 while heating the bump electrode 30 to a temperature lower than its melting point Tm, and [3] a bump electrode 30 of Tm-70 ° C. or higher. Heating step of heating to Tm + 200 ° C. or lower.

Hereinafter, each process will be described sequentially.
[1] First, the mounting substrate 1 and the semiconductor element 2 (semiconductor component) are prepared (preparation process).

  A mounting substrate 1 shown in FIG. 1 includes a base layer 11, a wiring layer 12, and a protective film 13, which are stacked in this order from the lower side of FIG. In such a mounting substrate 1, the upper surface 152 (first surface) is a mounting surface for mounting the semiconductor element 2.

  The base layer 11 is made of a semiconductor material such as silicon. The base layer 11 may be formed with circuit elements such as a transistor, a diode, and a resistor (not shown) as necessary.

  The wiring layer 12 electrically connects the semiconductor element 2 mounted on the mounting substrate 1 and the above-described circuit element, electrically connects the semiconductor element 2 or the circuit element, and an external circuit, An electric wiring for electrically connecting the elements or the semiconductor elements 2 is included, thereby forming a circuit. In each figure, circuit elements and electrical wiring are omitted or simplified.

  Examples of the constituent material of the protective film 13 include organic materials such as polyimide resins, polybenzoxazole resins, polyamide resins, and polyolefin resins, and inorganic materials such as silicon oxide and silicon nitride. .

  The mounting substrate 1 further includes a terminal 14 (first terminal) provided on the upper surface side of the wiring layer 12 and electrically connected to a circuit in the wiring layer 12. The upper end of the terminal 14 protrudes upward from the protective film 13 and is easily brought into contact with the terminal of the semiconductor element 2.

  The mounting substrate 1 is not limited to those described above, and can be replaced with various circuit members such as an organic wiring board, a glass wiring board, and a ceramic wiring board, and various semiconductor components.

  A semiconductor element 2 (second circuit member) shown in FIG. 1 includes a semiconductor chip 21, a wiring layer 22, and a protective film 23, which are stacked in order from the bottom of FIG. In such a semiconductor element 2, the lower surface 251 (second surface) is a mounting surface when mounted on the mounting substrate 1.

  The semiconductor chip 21 is made of a semiconductor material such as silicon. The semiconductor chip 21 is formed with circuit elements such as a transistor, a diode, and a resistor (not shown).

  The wiring layer 22 includes electrical wiring for electrically connecting the above-described circuit elements and for electrically connecting the circuit elements and an external circuit such as the mounting substrate 1. Is formed.

  Moreover, as a constituent material of the protective film 23, the material quoted as a constituent material of the protective film 13 is used, for example.

  The semiconductor element 2 further includes a through electrode 241 penetrating the semiconductor chip 21 in the thickness direction, a terminal 242 (second terminal) provided at the lower end of the through electrode 241, and projecting downward from the lower surface of the semiconductor chip 21. A terminal 243 provided at the upper end of the through electrode 241 and protruding upward from the upper surface of the semiconductor chip 21. The through electrode 241 and the terminal 242 and the through electrode 241 and the terminal 243 are electrically connected, respectively.

  The through electrode 241 is, for example, a TSV (Through-Silicon Via), and is specifically formed of a metal material including copper, aluminum, iron, nickel, gold, silver, or the like. Further, the terminal 242 and the terminal 243 are also made of these metal materials.

  In addition, the semiconductor element 2 is not limited to the above-mentioned thing, ie, a semiconductor component, For example, various circuit members, such as an organic wiring board, a glass wiring board, and a ceramic wiring board, can be substituted.

  By laminating the mounting substrate 1 and the semiconductor element 2 as described above, a semiconductor device having a connection structure in which highly reliable electrical connection is realized can be obtained.

On the other hand, in the preparation step, the bump electrode 30 (connection electrode) and the resin layer 4 are also prepared.
Among these, the bump electrode 30 is provided on the terminal 242 of the semiconductor element 2.

  The bump electrode 30 is, for example, a solder bump, and electrically and mechanically connects the terminal 242 of the semiconductor element 2 and the terminal 14 of the mounting substrate 1.

  Examples of the solder constituting the bump electrode 30 include lead-free solder containing Sn as a main component, such as Sn—Ag, Sn—Cu, Sn—Zn, and Sn—Ag—Cu. Of these, lead-free solder containing Sn as a main component and Ag as a subcomponent is preferably used. These lead-free solders have higher metal bonding strength and higher connection reliability than other lead-free solders. For this reason, it is useful as a solder constituting the bump electrode 30.

  In addition, although melting | fusing point Tm [degreeC] of the bump electrode 30 changes according to the kind of solder, it is preferable that it is 130-300 degreeC as an example, it is more preferable that it is 180-230 degreeC, and 210-230 degreeC. More preferably. Thereby, when the terminal 14 and the terminal 242 are connected via the bump electrode 30, the flux that the resin layer 4 has while minimizing the thermal influence (deterioration) on the mounting substrate 1 and the semiconductor element 2 due to heat. The function can also be fully expressed. For this reason, electrical connection with higher reliability can be achieved.

  1 is provided on the terminal 242 of the semiconductor element 2, the bump electrode 30 may be provided on the terminal 14 of the mounting substrate 1, and both the terminal 242 and the terminal 14 may be provided. May be provided.

  The resin layer 4 is provided on the lower surface 251 of the semiconductor element 2. The resin layer 4 is provided so as to cover the lower surface 251, and is also provided so as to cover the terminals 242 and the bump electrodes 30.

  This resin layer 4 has a flux function. Therefore, when the bump electrode 30 and the terminal 14 are in contact with each other via the resin layer 4, the flux function of the resin layer 4 is exhibited, and the terminal 242 and the terminal 14 are firmly metal-bonded via the bump electrode 30. be able to.

  In addition, the resin layer 4 in this preparation process is an uncured or semi-cured state. Since the resin layer 4 exhibits appropriate fluidity when heated, the resin layer 4 can be excluded from between the bump electrode 30 and the terminal 14, and can be joined without resin biting. That is, the resin layer 4 exhibits adhesiveness by curing, and bonds between the lower surface 251 of the semiconductor element 2 and the upper surface 152 of the mounting substrate 1.

  In the example of FIG. 1, the resin layer 4 is provided on the lower surface 251 of the semiconductor element 2, but the resin layer 4 may be provided on the upper surface 152 of the mounting substrate 1. It may be provided on both sides.

The resin layer 4 has a minimum melt viscosity of 10 to 10,000 Pa · s when measured at 1 Hz, and the viscosity at 1 Hz at 180 ° C. is η ₁ [Pa · s], and the viscosity at ₁₀ Hz is η ₁₀ [ Pa · s], the viscosity ratio η ₁ / η ₁₀ has a physical property value of 3 to 25. Such a resin layer 4 has so-called thixotropy, and is suitable as the resin layer 4 used for connection between the semiconductor element 2 and the mounting substrate 1. That is, the resin layer 4 having such physical property values has a relatively high viscosity when it is not subjected to a shearing force, whereas it has a relatively low viscosity when it is subjected to a shearing force. For this reason, when no load is applied between the mounting substrate 1 and the semiconductor element 2, the position between the upper surface 152 of the mounting substrate 1 and the lower surface 251 of the semiconductor element 2 is highly positional based on a relatively high viscosity. It is easy to temporarily fix each other.

  On the other hand, when a load is applied in a state of being sandwiched between the bump electrode 30 and the terminal 14 as will be described later, the viscosity decreases and the fluidity increases, and the gap between the bump electrode 30 and the terminal 14 increases. It becomes easy to be excluded. Therefore, the bump electrode 30 and the terminal 14 can be brought into contact without causing so-called resin biting. Furthermore, after the bump electrode 30 and the terminal 14 are in contact with each other, the viscosity of the resin layer 4 is increased, and the semiconductor element 2 and the mounting substrate 1 are easily maintained in a bonded state. For the above reasons, the resin layer 4 has the physical property values as described above, so that the terminal 14 and the terminal 242 are electrically connected through the bump electrode 30 with high positional accuracy and high reliability. Can do.

  Further, when such a resin layer 4 is not subjected to a shearing force, for example, a film-like form is easily maintained and has excellent handling properties. On the other hand, when the resin layer 4 is subjected to a shearing force, the viscosity decreases. Thus, the fluidity is increased, and the shape followability to the upper surface 152 and the lower surface 251 is increased. As a result, the upper surface 152 and the lower surface 251 can finally be bonded with sufficient strength via the resin layer 4.

  In addition, the minimum melt viscosity of the resin layer 4 is preferably 500 to 8000 Pa · s, and more preferably 1000 to 6000 Pa · s.

Moreover, the viscosity ratio η ₁ / η ₁₀ of the resin layer 4 is preferably 4 to 20, more preferably 5 to 15, and particularly preferably 5.5 to 10.

  The minimum melt viscosity of the resin layer 4 was measured at a rotation speed of 1 Hz using a rheometer while increasing the temperature of the resin layer 4 from 40 ° C. to 250 ° C. at a temperature increase rate of 10 ° C./min. When the minimum value of the measured value is obtained.

On the other hand, the viscosity η ₁ at 1 Hz at 180 ° C. of the resin layer 4 is obtained as the viscosity when measured after 50 seconds at a rotation speed of 1 Hz using a rheometer while raising the temperature of the resin layer 4 to 180 ° C. It is done.

Similarly, viscosity eta ₁₀ in 10Hz at 180 ° C. of the resin layer 4, as a viscosity when while raising the temperature of the resin layer 4 to 180 ° C., using a rheometer, was measured after 50 seconds at a rotation speed of 10Hz Desired.

Hereinafter, the resin layer 4 will be further described in detail.
The resin layer 4 according to the present embodiment includes, for example, the following components (a) to (f).
(A) Thermosetting resin Examples of the thermosetting resin include epoxy resins, phenoxy resins, cyanate resins, silicone resins, oxetane resins, phenol resins, (meth) acrylate resins, polyester resins (unsaturated polyester resins), and diallyl. A phthalate resin, a maleimide resin, a polyimide resin (polyimide precursor resin), a bismaleimide-triazine resin, and the like can be given, and those containing one or more of these are used. Specifically, the thermosetting resin is at least selected from the group consisting of epoxy resins, (meth) acrylate resins, phenoxy resins, cyanate resins, polyester resins, polyimide resins, silicone resins, maleimide resins, and bismaleimide-triazine resins. It is preferable that 1 type is included, and it is more preferable that epoxy resin is included. Epoxy resins are excellent in curability and storage stability. Further, the cured epoxy resin is excellent in heat resistance, moisture resistance and chemical resistance. In addition, the thermosetting resin mentioned above is not limited to the example mentioned above.

  The epoxy resin mentioned above contains two or more epoxy groups in 1 molecule, for example. Specifically, examples of the epoxy resin include a monofunctional epoxy resin, a bifunctional epoxy resin, and a polyfunctional epoxy resin.

  Among these, examples of the bifunctional epoxy resin include diallyl bisphenol A type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, o-allyl bisphenol A type epoxy resin, and the like.

  Examples of the polyfunctional epoxy resin include phenol novolac type epoxy resin, cresol novolac type epoxy resin, cresol naphthol type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, naphthalene skeleton type epoxy resin, 3,3 ′. , 5,5′-tetramethyl 4,4′-dihydroxybiphenyl type epoxy resin, 4,4′-dihydroxybiphenyl type epoxy resin, 1,6-dihydroxybiphenyl type epoxy resin, brominated cresol novolac type epoxy resin, tris ( Hydroxyphenyl) methane type epoxy resin, dicyclopentadiene type epoxy resin, 1,6 naphthalenediol glycidyl ether epoxy resin, aminophenol triglycidyl ether epoxy resin, etc. It is.

And the thermosetting resin mentioned above contains 1 type, or 2 or more types selected from these epoxy resins. In order to enhance the reliability of the resin composition, it is preferable that the ionic impurities (for example, Na ⁺ or Cl ⁻ ) contained in the epoxy resin be as small as possible.

  The epoxy resin described above is preferably at least partially liquid at 25 ° C. Thereby, the resin layer 4 can be satisfactorily filled around the terminals 242. Furthermore, the unevenness of the lower surface 251 of the semiconductor element 2 (for example, the unevenness generated by the terminal 242) can be effectively embedded. Furthermore, when the resin layer 4 is formed into a film, flexibility and flexibility can be imparted to the film. For this reason, the film excellent in handling property can be obtained.

  Epoxy resins that are at least partially liquid at 25 ° C. include, for example, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, o-allyl bisphenol A type epoxy resins, 3, 3 ′, 5, 5′-tetramethyl 4,4′-dihydroxybiphenyl type epoxy resin, 4,4′-dihydroxybiphenyl type epoxy resin, 1,6-dihydroxybiphenyl type epoxy resin, phenol novolac type epoxy resin, brominated cresol novolac type epoxy resin Bisphenol type epoxy resin, monoepoxy compound and the like, and one or more of these are included.

  In addition, the monoepoxy compound mentioned above has 1 type or 2 types or more selected from the glycidyl ether of 1, 6 naphthalene diol, the triglycidyl ether of aminophenols, and an epoxy group in 1 molecule | numerator, for example.

  The epoxy resin described above is particularly preferably a bisphenol A type epoxy resin or a bisphenol F type epoxy resin. Thereby, the resin layer 4 can be satisfactorily adhered to the semiconductor element 2. Furthermore, the resin layer 4 has excellent mechanical properties after curing.

The epoxy resin that is at least partially liquid at 25 ° C. preferably has a viscosity at 25 ° C. of 5.0 × 10 ² mPa · s to 5.0 × 10 ⁴ mPa · s, and has a viscosity at 25 ° C. More preferably, it is 8.0 × 10 ² mPa · s or more and 4.0 × 10 ⁴ mPa · s or less. By making the viscosity at 25 ° C. within the above range, the produced film (resin layer 4) has appropriate flexibility and excellent handling properties.

  The epoxy resin may be a tris (hydroxyphenyl) methane type epoxy resin, a naphthalene type epoxy resin, or the like. In this case, since the epoxy resin has a high glass transition point Tg, the thermal reliability is increased. The epoxy resin may be a dicyclopentadiene type epoxy resin. In this case, the water absorption is low. In addition, when a naphthalene type epoxy resin and a dicyclopentadiene type epoxy resin are used in combination, the glass transition point Tg becomes high, the water absorption becomes low, and flame retardancy is improved.

  It is preferable that content of a thermosetting resin is 10 mass% or more and 75 mass% or less with respect to the whole resin composition. More specifically, the content of the thermosetting resin is preferably 15% by mass or more and 45% by mass or less with respect to the entire resin composition. When the content of the thermosetting resin is within the above-described range, the cured resin layer 4 has particularly excellent heat resistance and mechanical properties. However, the content of the thermosetting resin is not limited to the above-described range.

(B) Compound having flux function The resin layer 4 has a flux function as described above. This flux function is manifested when the resin layer 4 contains a compound having a flux function. By exhibiting the flux function, it becomes easy to remove the metal oxide film present on the surface of the bump electrode 30, and good metal bonding is realized.

  The bump electrode 30 is used for connection between the terminal 14 and the terminal 242 at a temperature lower than the melting point in a mounting process described later. Therefore, when the resin layer 4 contains a compound having a flux function, good metal bonding can be realized even at a low temperature.

  The compound having a flux function is not particularly limited as long as it has a function of removing the metal oxide film on the surface of the bump electrode 30, but a compound having one or both of a carboxyl group and a phenolic hydroxyl group is preferable. .

  In addition, examples of the compound having a flux function include acid anhydride compounds.

  The blending amount of the compound having a flux function in the total solid content of the resin layer 4 is not particularly limited, but is preferably 0.1% by mass or more and 30% by mass or less, and 0.5% by mass or more and 20% by mass or less. More preferably, it is 1.0 mass% or more and 10 mass% or less.

  When the compounding amount of the compound having the flux function is within the above range, the flux function can be improved, and when the resin layer 4 is cured, an unreacted epoxy resin or a compound having the flux function remains. Can be prevented, and migration resistance can be improved.

  In addition, among the compounds that act as curing agents for epoxy resins, there are compounds having a flux function (hereinafter, such compounds are also referred to as “curing agents having a flux function”). For example, aliphatic dicarboxylic acids, aromatic dicarboxylic acids and the like that act as curing agents for epoxy resins also have a flux function. In the present embodiment, such a curing agent having a flux function can also be suitably used.

  In addition, the compound which has a flux function provided with a carboxyl group has one or more carboxyl groups in the molecule, and may be liquid or solid. Moreover, the compound which has a flux function provided with a phenolic hydroxyl group has one or more phenolic hydroxyl groups in the molecule, and may be liquid or solid. In addition, the compound having a flux function including a carboxyl group and a phenolic hydroxyl group has one or more carboxyl groups and phenolic hydroxyl groups in the molecule, and may be liquid or solid.

  Of these, examples of the compound having a flux function having a carboxyl group include aliphatic carboxylic acids and aromatic carboxylic acids.

  Examples of the aliphatic carboxylic acid relating to the compound having a flux function having a carboxyl group include a compound represented by the following general formula (1), formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid pivalate, and capryl. Examples include acid, lauric acid, myristic acid, palmitic acid, stearic acid, acrylic acid, methacrylic acid, crotonic acid, oleic acid, fumaric acid, maleic acid, oxalic acid, malonic acid, oxalic acid, and the like.

_{HOOC- (CH 2) n -COOH (} 1)
(In formula (1), n represents an integer of 1 or more and 20 or less.)

  Aromatic carboxylic acids related to the compound having a flux function with a carboxyl group include benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, hemimellitic acid, trimellitic acid, trimesic acid, merophanic acid, planitic acid, pyromellitic acid , Merit acid, xylyl acid, hemelic acid, mesitylene acid, prenylic acid, toluic acid, cinnamic acid, salicylic acid (2-hydroxybenzoic acid), 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid Acid, 2,4-dihydroxybenzoic acid, gentisic acid (2,5-dihydroxybenzoic acid), 2,6-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, gallic acid (3,4,5-trihydroxy Benzoic acid), 1,4-dihydroxy-2-naphthoic acid, 3,5-dihydroxy Naphthoic acid derivatives such as 2-naphthoic acid, phenolphthalein, diphenol acid.

  Among these compounds having a flux function having a carboxyl group, the activity of the compound having a flux function, the amount of outgas generated during curing of the resin composition, and the elastic modulus and glass transition temperature of the cured resin composition From the viewpoint of good balance such as the above, the compound represented by the general formula (1) is preferable. And among the compounds shown by the said General formula (1), while the compound whose n is 3-10 can suppress that the elasticity modulus in the resin layer 4 after hardening increases, the semiconductor element 2 or It can be preferably used in that the adhesion between circuit members such as the mounting substrate 1 can be improved.

Among the compounds represented by the general formula (1), examples of the compound in which n is 3 to 10 include, for example, n = 3 glutaric acid (HOOC— (CH ₂ ) ₃ —COOH), n = 4 adipic acid _{(HOOC- (CH 2) 4 -COOH} ), n = 5 of pimelic acid _{(HOOC- (CH 2) 5 -COOH} ), sebacic acid of _{n = 8 (HOOC- (CH 2} ) 8 -COOH) , and n = 10 HOOC— (CH ₂ ) ₁₀ —COOH— and the like.

  Examples of the compound having a flux function having a phenolic hydroxyl group include phenols. Specifically, for example, phenol, o-cresol, 2,6-xylenol, p-cresol, m-cresol, o-ethylphenol, 2,4-xylenol, 2,5 xylenol, m-ethylphenol, 2, 3-xylenol, meditol, 3,5-xylenol, p-tertiarybutylphenol, catechol, p-tertiaryamylphenol, resorcinol, p-octylphenol, p-phenylphenol, bisphenol A, bisphenol F, bisphenol AF, biphenol, diallyl Examples thereof include monomers containing a phenolic hydroxyl group such as bisphenol F, diallyl bisphenol A, trisphenol, and tetrakisphenol.

  A compound having either a carboxyl group or a phenolic hydroxyl group as described above, or a compound having both a carboxyl group and a phenolic hydroxyl group is taken in three-dimensionally by reaction with an epoxy resin. Therefore, from the viewpoint of improving the formation of a three-dimensional network of the epoxy resin after curing, it is preferable to use a curing agent having a flux function as the compound having a flux function. As a hardening | curing agent which has a flux function, the compound provided with the hydroxyl group which can be added to an epoxy resin and the carboxyl group which shows a flux function (oxide film removal function) in 1 molecule is mentioned, for example.

  Examples of the curing agent having such a flux function include salicylic acid (2-hydroxybenzoic acid), 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, and gentidine. Benzoic acid derivatives such as acids (2,5-dihydroxybenzoic acid), 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, gallic acid (3,4,5-trihydroxybenzoic acid), 1, Naphthoic acid derivatives such as 4-dihydroxy-2-naphthoic acid, 3,5-dihydroxy-2-naphthoic acid, 3,7-dihydroxy-2-naphthoic acid, phenolphthaline, diphenolic acid, etc. 1 type (s) or 2 or more types are used in combination.

  Among these, it is preferable to use a compound having one carboxyl group and one hydroxyl group in the molecule as the compound having a flux function from the balance between the high flux function and the appropriate reactivity with respect to the thermosetting resin. . As a result, the metal oxide film on the surface of the bump electrode 30 can be effectively removed even under heating conditions at a relatively low temperature.

  Particularly preferred compounds include compounds having one phenolic hydroxyl group and one carboxyl group in the molecule, and specifically include salicylic acid (2-hydroxybenzoic acid), 3-hydroxybenzoic acid, 4-hydroxybenzoic acid. Mention may be made of acids.

  Since these compounds are relatively easily available and have extremely high flux activity, they can be particularly preferably used in this embodiment.

  Further, the blending amount of the curing agent having a flux function in the total solid content of the resin layer 4 is not particularly limited, but is preferably 0.1% by mass or more and 30% by mass or less, and 0.5% by mass or more. It is more preferably 20% by mass or less, and particularly preferably 1.0% by mass or more and 10% by mass or less. Thereby, while being able to improve the flux function of the resin layer 4, it is taken in stably in a thermosetting resin.

  Examples of acid anhydrides having a flux function include aliphatic acid anhydrides, alicyclic acid anhydrides, and aromatic acid anhydrides.

  Examples of the aliphatic acid anhydride related to the compound having a flux function include succinic anhydride, polyadipic acid anhydride, polyazeline acid anhydride, polysebacic acid anhydride, and the like.

  Examples of alicyclic acid anhydrides related to the compound having a flux function include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylhymic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, and trialkyltetrahydrophthalic anhydride. Examples thereof include acid and methylcyclohexene dicarboxylic acid anhydride.

  Examples of aromatic acid anhydrides related to the compound having a flux function include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bistrimellitate, glycerol tris trimellitate, etc. It is done.

  When an epoxy resin is used as the thermosetting resin, the compounding ratio (mass ratio) between the epoxy resin and the compound having a flux function is not particularly limited, but (epoxy resin / compound having a flux function) is 0.5 or more and 12 Is preferably 2 or less and particularly preferably 2 or more and 10 or less. By setting (epoxy resin / compound having a flux function) within the above range, the resin layer 4 can be stably cured, and migration resistance can be improved.

(C) Film forming resin The film forming resin improves the film forming property of the resin layer 4. The film-forming resin is soluble in an organic solvent and can form a film alone.

  Examples of the film forming resin include (meth) acrylic resin, phenoxy resin, polyester resin, polyurethane resin, polyimide resin, siloxane-modified polyimide resin, polybutadiene, polypropylene, styrene-butadiene-styrene copolymer, and styrene-ethylene-butylene. -Styrene copolymer, polyacetal resin, polyvinyl butyral resin, polyvinyl acetal resin, butyl rubber, chloroprene rubber, polyamide resin, acrylonitrile-butadiene copolymer, acrylonitrile-butadiene-acrylic acid copolymer, acrylonitrile-butadiene-styrene copolymer , Polyvinyl acetate, nylon and the like, and those containing one or more of them are used. Specifically, the film-forming resin preferably contains at least one selected from the group consisting of (meth) acrylic resins, phenoxy resins, and polyimide resins. The film-forming resin may have an epoxy group, a (meth) acryl group, a carboxyl group, a phenolic hydroxyl group, or the like in the structure. The film forming resin is preferably any one of (meth) acrylic resin, phenoxy resin, polyimide resin, and acrylonitrile-butadiene copolymer. In this case, since the film-forming resin is excellent in flexibility, the temperature cycle reliability is improved. In the present embodiment, “(meth) acrylic resin” refers to (meth) acrylic acid polymer, (meth) acrylic acid derivative polymer, (meth) acrylic acid and other monomers. Or a copolymer of a derivative of (meth) acrylic acid and another monomer. Furthermore, “(meth) acrylic acid” means “acrylic acid” or “methacrylic acid”.

  The weight average molecular weight of the film-forming resin is preferably 10,000 or more, more preferably 20,000 to 1,000,000, and even more preferably 30,000 to 900,000. When the weight average molecular weight of the film forming resin is within the above range, the film forming resin can particularly enhance the film forming property of the resin layer 4.

  In addition, when preparing the resin layer 4 as a film, it is preferable that content of film forming resin is 0.5 mass% or more and 50 mass% or less with respect to the whole resin layer 4, 1 mass% or more It is more preferably 40% by mass or less, and further preferably 3% by mass or more and 35% by mass or less. When the content of the film forming resin is within the above range, the fluidity of the resin layer 4 can be suppressed, and the film (resin layer 4) can be easily handled. However, the content of the film forming resin is not limited to the above-described range.

(D) Curing accelerator The curing accelerator promotes curing of the above-described (a) thermosetting resin. A hardening accelerator can be suitably selected according to the kind of thermosetting resin. The curing accelerator is, for example, an imidazole compound. The imidazole compound includes, for example, one or more selected from the group consisting of 2-phenyl-4-methylimidazole, 2-phenylhydroxyimidazole, and 2-phenyl-4-methylhydroxyimidazole. The imidazole compound has an excellent balance between bondability and curability, and in particular, bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene skeleton type epoxy resin, tris (hydroxyphenyl) methane type epoxy resin, or dicyclopentadiene type. By using it in combination with an epoxy resin, the effect can be expressed highly. Furthermore, the imidazole compound preferably has a melting point of 150 ° C. or higher. Thereby, before the hardening of the resin layer 4 is completed, the components constituting the bump electrode 30 can easily move on the surface of the terminal 14 or the surface of the terminal 242. Thereby, the electrical connection between the terminal 14 and the bump electrode 30 and the electrical connection between the terminal 242 and the bump electrode 30 can be improved. Examples of the imidazole compound having a melting point of 150 ° C. or higher include 2-phenyl-4-methylimidazole, 2-phenylhydroxyimidazole, 2-phenyl-4-methylhydroxyimidazole, and the like, one or two of these. Those containing more than seeds are used.

  The content of the curing accelerator is preferably 0.005% by mass or more and 10% by mass or less, and more preferably 0.01% by mass or more and 5% by mass or less in the entire resin layer 4. Thereby, it can suppress that the viscosity of the resin layer 4 becomes high too high in the vicinity of the melting temperature of the bump electrode 30. Furthermore, the preservability of the resin layer 4 can be further improved. However, the content of the curing accelerator is not limited to the above-described range.

(E) Filler The filler reduces the linear expansion coefficient of the resin layer 4 and adjusts the minimum melt viscosity of the resin layer 4. The filler includes, for example, at least one of an organic filler and an inorganic filler. Examples of the organic filler include resin particles and rubber particles. Examples of the constituent material of the inorganic filler include silver, titanium oxide, silica, mica, alumina, aluminum nitride, titanium oxide, silicon nitride, and boron nitride, and one or more of these are used. It is done.

  The filler preferably contains an organic filler from the viewpoint of improving impact resistance. The organic filler used in this case preferably contains, for example, rubber particles containing a rubber component. Examples of the rubber component include acrylic rubber, silicon rubber, butadiene rubber, and the like, and one or more of these are used. Thereby, the toughness of the hardened | cured material of the resin layer 4 can be improved, and the impact resistance of the connection structure of the mounting substrate 1 and the semiconductor element 2 can be improved. The organic filler may have a core-shell structure. As an organic filler having a core-shell structure, for example, organic fine particles (manufactured by Dow Chemical: Paraloid EXL2655 impact resistance enhancer), stress relieving agent (manufactured by Mitsubishi Rayon: Metabrene J-), which are excellent in warpage suppression characteristics of circuit members when bonded, are used. 5800, W-5500) and the like.

  From the viewpoint of improving the reliability of the circuit member connection structure, the filler preferably contains an inorganic filler. Thereby, the linear expansion coefficient of the resin layer 4 can be reduced, and the reliability of the connection structure of a circuit member can be improved. More specifically, the inorganic filler preferably contains silica from the viewpoint of thermal conductivity of the cured resin layer 4. The shape of the silica is, for example, at least one of crushed silica and spherical silica. In the present embodiment, the shape of silica is preferably spherical silica. Furthermore, the inorganic filler preferably contains one or more selected from the group consisting of aluminum oxide, aluminum nitride, titanium oxide, silicon nitride, and boron nitride in consideration of thermal conductivity.

  The filler preferably contains both an inorganic filler and an organic filler from the viewpoint of improving the impact resistance and improving the reliability of the circuit member connection structure.

  The average particle diameter of the filler is not particularly limited, but is preferably 500 nm or less, and more preferably 300 nm or less. On the other hand, the lower limit value of the average particle diameter of the filler is, for example, 5 nm. When the average particle diameter of the filler is within the above range, the viscosity of the resin layer 4 can be made moderate. Further, the filler can be prevented from aggregating in the resin layer 4. Furthermore, when the light passes through the resin layer 4, it is possible to reduce the filler from inhibiting visible light transmission. In this case, even if the terminal 242 and the bump electrode 30 are embedded in the resin layer 4, the position of the terminal 242 and the position of the bump electrode 30 can be well recognized using visible light. When the filler contains silica, the visible light transmission is further improved. Thereby, alignment of the semiconductor element 2 becomes easy. However, the average particle diameter of the filler is not limited to the above-described range.

  The average particle diameter of the filler is, for example, the particle diameter when the cumulative particle diameter is 50% in the volume-based particle size distribution obtained by the laser diffraction method.

  The content of the filler in the resin layer 4 is preferably 0.1% by mass or more and 80% by mass or less, and more preferably 20% by mass or more and 70% by mass or less. When the content of the filler is within the above range, the linear expansion coefficient difference between the semiconductor element 2 and the resin layer 4 can be reduced after the resin layer 4 is cured. Thereby, the stress which arises between the semiconductor element 2 and the resin layer 4 can be reduced. For this reason, it can suppress more reliably that the semiconductor element 2 peels from the resin layer 4. FIG. Furthermore, it can suppress that the elasticity modulus of the resin layer 4 after hardening becomes it too high that content of a filler exists in the said range. For this reason, the reliability of the connection structure of a circuit member increases. However, the content of the filler is not limited to the above-described range.

(F) Other additive The resin layer 4 may contain components other than (a)-(e) mentioned above as needed. For example, when an epoxy resin is used as the thermosetting resin, the resin layer 4 according to this embodiment may include a phenolic curing agent having a weight average molecular weight of 300 or more and 2500 or less. Thereby, the glass transition temperature of the hardened | cured material of the resin layer 4 can be raised, and also it becomes possible to improve ion migration resistance. Moreover, moderate flexibility can be imparted to the resin layer 4.

  The phenolic curing agent includes, for example, one or more selected from the group consisting of a phenol novolak resin, a cresol novolak resin, a bisphenol A type novolak resin, a bisphenol F type novolak resin, and a bisphenol AF type novolak resin. More specifically, the phenolic curing agent is preferably a phenol novolac resin or a cresol novolac resin.

  The content of the phenol-based curing agent is preferably 1% by mass or more and 30% by mass or less, and more preferably 3% by mass or more and 25% by mass or less in the entire resin layer 4. By setting the content of the phenolic curing agent within the above range, the unevenness of the lower surface 251 of the semiconductor element 2 can be effectively embedded in the resin layer 4. Furthermore, the glass transition temperature of the hardened | cured material of the resin layer 4 can be raised effectively by making content of a phenol type hardening | curing agent into the said range. However, content of a phenol type hardening | curing agent is not limited to the range mentioned above.

  The weight average molecular weight of the phenolic curing agent is preferably 300 or more and 2500 or less, and particularly preferably 400 or more and 2300 or less. Thereby, the glass transition temperature of the hardened | cured material of the resin layer 4 can be raised, and also ion migration resistance can be improved efficiently. Moreover, moderate flexibility can be imparted to the resin layer 4. Here, the weight average molecular weight can be measured by GPC (gel permeation chromatogram).

  The resin layer 4 may further contain a silane coupling agent. In this case, the resin layer 4 can be favorably adhered to the semiconductor element 2. The silane coupling agent includes, for example, one or two selected from an epoxy silane coupling agent and an aromatic-containing aminosilane coupling agent. The blending amount of the silane coupling agent is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less, and still more preferably in the entire resin layer 4. It is 0.1 mass% or more and 2 mass% or less. However, the compounding amount of the silane coupling agent is not limited to this range.

  The resin layer 4 may further contain a thixotropic agent. In this case, the thixo properties of the resin layer 4 can be controlled to a good level. And while being able to prevent resin biting, the protrusion of the resin layer can be prevented. Examples of the thixo modifier include “BYK-405” manufactured by Big Chemie Japan, “BYK-R606” manufactured by Big Chemy Japan, and the like.

  The blending amount of the thixotropic agent is preferably 0.01% by mass or more and 1% by mass or less, more preferably 0.01% by mass or more and 0.09% by mass or less, and more preferably in the entire resin layer 4. Is 0.02 mass% or more and 0.08 mass% or less. However, the blending amount of the thixo adjuster is not limited to this range.

  The resin layer 4 may further contain an additive. The additive contains, for example, one or more selected from plasticizers, stabilizers, tackifiers, lubricants, antioxidants, antistatic agents, and pigments.

  The material for forming the resin layer 4 can be prepared by mixing or dispersing the components (a) to (f) described above. The mixing method and dispersion method of each component are not specifically limited, It can mix or disperse | distribute by a conventionally well-known method. More specifically, for example, the above-described forming material is prepared in a liquid state by mixing the above components in a solvent or without a solvent. The solvent used at this time is inactive with respect to each component. Examples of the solvent include ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), diisobutyl ketone (DIBK), cyclohexanone and diacetone alcohol (DAA), and aromatics such as benzene, xylene and toluene. Hydrocarbons, methyl alcohol, ethyl alcohol, isopropyl alcohol, alcohols such as n-butyl alcohol, methyl cellosolve, ethyl cellosolve, propylene glycol monomethyl ether (PGME), cellosolve such as butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), dimethylformamide (DMF), dibasic acid ester (DBE), 3- Tokishipuropion ethyl (EEP), dimethyl carbonate (DMC) and the like, those containing one or more of these are used. The content of the solvent is preferably adjusted so that the concentration of the mass of the forming material with respect to the sum of the mass of the solvent and the solid content of the forming material is 10 to 80% by mass.

  [2] Next, while heating the bump electrode 30 to a temperature lower than its melting point Tm, the semiconductor element 2 is pressed against the mounting substrate 1 from above. That is, the mounting substrate 1 and the semiconductor element 2 are pressed against each other (see FIG. 2A). Thereby, the terminal 14 of the mounting substrate 1 and the bump electrode 30 provided on the terminal 242 of the semiconductor element 2 approach each other and come into contact with each other. At this time, the resin layer 4 interposed between the terminal 14 and the bump electrode 30 is pushed away by the approach of the terminal 14 and the bump electrode 30 (mounting process). As a result, when the terminal 14 and the bump electrode 30 come into contact with each other, so-called resin biting is prevented at the contact point, and the resin layer 4 is removed (see FIG. 2B).

  The heating temperature in this step is set to a temperature lower than the melting point of the bump electrode 30 as described above. At such a temperature, the bump electrode 30 does not melt, but atomic diffusion occurs at the contact interface. For this reason, metal bonding occurs between the terminal 14 and the bump electrode 30, and the terminal 14 and the terminal 242 are electrically and mechanically connected via the bump electrode 30 (see FIG. 2C). .

  In addition, by setting such a temperature, it is possible to suppress significant softening of the resin layer 4 and to prevent the resin layer 4 from protruding from between the mounting substrate 1 and the semiconductor element 2, Since the bump electrode 30 does not melt, the resin layer 4 can be pushed away efficiently.

  Further, when the bump electrode 30 is heated, the temperature of the mounting substrate 1 and the semiconductor element 2 also rises accordingly. By the way, in the mounting substrate 1 and the semiconductor element 2, since the member mainly comprised by the semiconductor material and the member mainly comprised by the resin material are laminated | stacked, respectively, curvature is easy to generate | occur | produce. This warpage increases as the heated temperature increases.

  Therefore, as in the present embodiment, the bump electrode 30 is heated to a temperature lower than its melting point, so that the mounting substrate 1 and the semiconductor element 2 can be prevented from greatly warping in this step. Thereby, even when the size of the mounting substrate 1 or the semiconductor element 2 is large, the amount of displacement due to warping can be kept small. As a result, for example, when a plurality of terminal pairs each including the terminal 14 and the terminal 242 are provided, it is possible to prevent the inter-terminal distance from becoming uneven depending on the position of the terminal pair. As a result, the conductivity of each terminal pair can be made uniform.

  The heating temperature in this step may be lower than the melting point of the bump electrode 30, but when the melting point of the bump electrode 30 is Tm [° C.], it is preferably Tm−5 ° C. or less, and Tm−10 ° C. or less. More preferably, it is more preferably Tm-20 ° C or lower. Thereby, since the bump electrode 30 is not melted, it is possible to avoid the bump electrode 30 from being largely crushed in this step. Moreover, the displacement amount accompanying the curvature of the mounting substrate 1 or the semiconductor element 2 can be suppressed small, and for example, the conductivity of each terminal pair can be made uniform.

  On the other hand, the lower limit value of the heating temperature in this step is not particularly set, but is preferably Tm−70 ° C. or higher, and more preferably Tm−50 ° C. or higher. Thereby, since the resin layer 4 can be sufficiently softened, the resin layer 4 interposed between the terminal 14 and the bump electrode 30 can be pushed away more reliably. In addition, since the flux function of the resin layer 4 is sufficiently developed, the metal oxide film on the surface of the bump electrode 30 can be removed in this step, so that good metal bonding can be generated.

  In addition, the heating temperature in this process should just be temperature lower than melting | fusing point Tm of the bump electrode 30, However, It is preferable that it is lower than the heating temperature in the heating process mentioned later, 5 degrees C or more is more preferable, 10 degrees C or more More preferably, it is low. Thereby, the effect by each process is show | played more reliably.

  In addition, it is preferable that an alloy or an intermetallic compound accompanying atomic diffusion is generated between the bump electrode 30 and the terminal 14 and between the bump electrode 30 and the terminal 242, respectively. And metal joining can be advanced reliably.

  In addition, the specific heating temperature in this step changes as appropriate according to the melting point of the bump electrode 30, but as an example, it is preferably 150 ° C. or higher and 220 ° C. or lower, more preferably 180 ° C. or higher and 220 ° C. or lower. preferable.

  In addition, the time for applying pressure while heating in this step is not particularly limited, but is preferably 0.1 second or longer and 60 seconds or shorter, and more preferably 0.5 second or longer and 10 seconds or shorter. Thereby, sufficient time is secured to push away the resin layer 4. Moreover, even when there are a plurality of terminal pairs, their heating temperatures can be made sufficiently uniform, and the conductivity of each terminal pair can be made uniform.

  The bump electrode 30 is heated by heat conduction via a jig (for example, a flip chip bonder stage or head) for pressing the mounting substrate 1 and the semiconductor element 2 together.

  In this step, when the mounting substrate 1 and the semiconductor element 2 are pressed against each other, the load applied to each bump electrode 30 is preferably 0.5 to 10 gf (0.0049 to 0.098 N). It is more preferably 8 to 8 gf (0.0078 to 0.078 N), and further preferably 1.0 to 6.0 gf (0.0098 to 0.059 N). Further, such a load is preferably applied to the bump electrode 30 for 0.1 to 60 seconds, more preferably 0.5 to 30 seconds, and particularly preferably 1.0 to 20 seconds. In this way, the terminal 14 of the mounting substrate 1 and the terminal 242 of the semiconductor element 2 are pressed against each other so that an appropriate load is applied to the bump electrode 30 for a relatively short time. In addition, it is difficult for the resin layer 4 to remain, and the bump electrode 30 can be prevented from being significantly deformed. That is, by applying an appropriate load for a short time, the resin layer 4 between the bump electrode 30 and the terminal 14 can be more reliably removed. As a result, it is possible to create a state in which the bump electrode 30 and the terminal 14 are in contact (so-called resin biting can be prevented). By forming such a state in this step, good metal bonding is performed in the heating step described later, and a reliable electrical connection is established between the terminal 14 and the terminal 242 via the bump electrode 30. Can be achieved. Further, the bump electrode 30 can be prevented from being largely crushed, and the resin layer 4 can be prevented from protruding from between the mounting substrate 1 and the semiconductor element 2.

  When the load applied to each bump electrode 30 falls below the lower limit value, or when the load application time falls below the lower limit value, depending on the shape of the bump electrode 30, the thickness of the resin layer 4, etc. There is a possibility that the bump electrode 30 and the terminal 14 cannot be brought into contact with each other. On the other hand, when the load applied to each bump electrode 30 exceeds the upper limit value, or when the load application time exceeds the upper limit value, the bump electrode 30 is greatly deformed, or the resin layer 4 is more than necessary. There is a possibility of being crushed and protruding from between the mounting substrate 1 and the semiconductor element 2.

  Note that the load applied to each bump electrode 30 is the same as that applied when the mounting substrate 1 and the semiconductor element 2 are pressed against each other, and the load of the bump electrode 30 provided between the mounting substrate 1 and the semiconductor element 2 is the same. It is obtained by dividing by the number.

  In this step, when the mounting substrate 1 and the semiconductor element 2 are pressed against each other, the maximum speed in the process in which the terminal 14 and the terminal 242 approach each other is preferably 0.01 to 1 mm / second, and 0.03 More preferably, it is -0.5 mm / second, and it is especially preferable that it is 0.05-0.3 mm / second. By setting the maximum speed at which the terminal 14 and the terminal 242 are brought close to each other within the above range, the shear force is applied to the resin layer 4 at an appropriate speed on the basis of the thixotropy of the resin layer 4. Softens. For this reason, the resin layer 4 hardly remains between the bump electrode 30 and the terminal 14. For this reason, the resin layer 4 between the bump electrode 30 and the terminal 14 can be more reliably removed, and so-called resin biting can be suppressed.

  Furthermore, by applying the shearing force at a sufficient speed, it is possible to prevent so-called resin biting even if the viscosity when the shearing force is not applied is relatively high. Therefore, the adhesive force of the resin layer 4 in other than the mounting process can be increased, and the resin layer 4 can be formed between the mounting substrate 1 and the semiconductor element 2 while bonding the mounting substrate 1 and the semiconductor element 2 more firmly. It is possible to suppress the protrusion.

  The maximum speed is a value when the speed becomes maximum in the process in which the terminal 14 and the terminal 242 approach each other.

  [3] Next, the bump electrode 30 is heated to a temperature of Tm−70 ° C. or higher and Tm + 200 ° C. or lower. Thereby, alloying further proceeds between the bump electrode 30 and the terminal 14 and between the bump electrode 30 and the terminal 242, and the connection part 3 is obtained (heating process). And the terminal 14 and the terminal 242 are electrically connected through the connection part 3 (refer FIG.2 (c)).

  The heating temperature in this step is Tm−70 ° C. or higher and Tm + 200 ° C. or lower. Thereby, since alloying advances favorably between the bump electrode 30 and the terminal 14 and between the bump electrode 30 and the terminal 242, good electrical connection can be achieved at these connection interfaces. On the other hand, since the amount of heat applied to the mounting substrate 1 and the semiconductor element 2 can be minimized, the thermal shock can be suppressed and the occurrence of damage or the like can be suppressed.

  The bump electrode 30 may be heated by heat conduction via a jig (for example, a flip chip bonder stage or head) for pressing the mounting substrate 1 and the semiconductor element 2 together. You may carry out by heating the atmosphere which arrange | positions the semiconductor element 2. FIG.

  In addition, this step may be performed without applying a load that presses the mounting substrate 1 and the semiconductor element 2 together, or may be performed with a load applied.

  Among these, in the former case, even when the bump electrode 30 is melted, the bump electrode 30 is not easily crushed. For this reason, the distance between the terminal 14 and the terminal 242 does not change so much and the resin layer 4 is suppressed from being crushed. As a result, the resin layer 4 can be prevented from protruding from between the mounting substrate 1 and the semiconductor element 2.

  On the other hand, in the latter case, the load applied to each bump electrode 30 is slightly different depending on the heating temperature in this step, but may be larger or smaller than the mounting step described above.

  The time for heating in this step is not particularly limited, and is appropriately set according to the heating temperature, but is preferably 1 second or longer and 10 hours or shorter, and is preferably 3 seconds or longer and 5 hours or shorter. More preferred.

As described above, a stacked body (semiconductor device) obtained by stacking the semiconductor elements 2 on the mounting substrate 1 is obtained. In other words, a connection structure (circuit member connection structure) formed by connecting the mounting substrate 1 and the semiconductor element 2 is obtained.
Thereafter, if necessary, the semiconductor element 2 may be sealed with a sealing material.

  In addition, although heating conditions, such as heating temperature in this process, pressure, and heating time, can be set as mentioned above, More preferably, within the range of said setting conditions, the following (A)-(C) Are set to the heating conditions shown in FIG.

Hereinafter, the methods (A) to (C) will be described.
(A)
[A3-1] First, the bump electrode 30 is heated at a temperature lower than the melting point Tm. Thereby, the resin layer 4 is cured, and the mounting substrate 1 and the semiconductor element 2 are bonded by the cured resin layer 4.

  Here, in the step [2], the mounting substrate 1 and the semiconductor element 2 are laminated in a state in which the occurrence of warpage is suppressed. In this state, the resin layer 4 is formed in the step [A3-1]. Harden. Therefore, the mounting substrate 1 and the semiconductor element 2 are bonded together in a state where the occurrence of warpage is suppressed.

  The heating temperature (second temperature) in this step is set lower than the melting point Tm of the bump electrode 30 as in the step [2]. Note that the second temperature may be higher or lower than the first temperature.

  The specific heating temperature in this step changes as appropriate according to the melting point Tm of the bump electrode 30, but as an example, it is preferably Tm−70 ° C. or higher and Tm−5 ° C. or lower, and Tm−60 ° C. or higher and Tm. It is more preferably −10 ° C. or lower, and further preferably Tm−50 ° C. or higher and lower than Tm−15 ° C. Specifically, it is preferably set to 150 ° C. or higher and 215 ° C. or lower, more preferably 160 ° C. or higher and 210 ° C. or lower, and further preferably 170 ° C. or higher and 205 ° C. or lower. As a result, the resin layer 4 is cured without significantly affecting the bump electrode 30. As a result, the mounting substrate 1 and the semiconductor element 2 can be bonded with sufficient strength through the resin layer 4. For example, the mounting substrate 1 or the semiconductor element 2 is deformed such as warpage in a process described later. Even if there is a risk of occurrence, it can be suppressed. Thereby, it is possible to suppress the occurrence of a problem that occurs when deformation such as warpage occurs, for example, a problem that the electrical connection between the bump electrode 30 and the terminal 14 and the terminal 242 is released.

  Moreover, since the bump electrode 30 is not melted, it is possible to avoid the bump electrode 30 from being largely crushed even when this step is performed under pressure.

  Moreover, it is preferable that the heating temperature in this process [A3-1] is less than the heating temperature in process [A3-2] mentioned later, and is heating temperature -5 degrees C or less in process [A3-2] mentioned later. Is more preferable. Thereby, in this process, since heat treatment is performed at a lower temperature than the process [A3-2] described later, deformation amount such as warpage in the mounting substrate 1 and the semiconductor element 2 can be sufficiently suppressed, and the resin is maintained in that state. Layer 4 can be cured. For this reason, even if there is a possibility that the mounting substrate 1 or the semiconductor element 2 may be deformed in the heating process, it can be sufficiently suppressed.

  In addition, the time for applying pressure while heating in this step is not particularly limited, but is set longer than the heating time in step [2]. For example, it is preferably 30 minutes or more and 5 hours or less, preferably 1 hour or more and 3 hours or more. More preferably, it is less than or equal to the time.

  Furthermore, the atmosphere in this step may be either an air atmosphere or an inert gas atmosphere.

  Further, the heat treatment in this step may be performed under normal pressure or under pressure. When pressurizing, the load applied per bump electrode 30 is preferably larger than the load applied per bump electrode 30 in the step [2].

  The specific pressure is, for example, preferably set to 0.1 MPa to 10 MPa, more preferably set to 0.4 MPa to 1.2 MPa, and further preferably set to 0.6 MPa to 1.0 MPa. . Thereby, it is possible to cure the resin layer 4 in a state where the shape of the resin layer 4 is satisfactorily maintained (for example, a state in which warpage is suppressed) while suppressing the bump electrode 30 from being largely crushed in this step. As a result, a highly reliable electrical connection is finally achieved between the mounting substrate 1 and the semiconductor element 2, and a stacked structure with high dimensional accuracy is obtained even when the mounting substrate 1 and the semiconductor element 2 are stacked. be able to. Further, by curing the resin layer 4 under pressure, generation of voids in the resin layer 4 can be accurately suppressed or prevented.

  In addition, the heating temperature in this step may be changed from 150 ° C. to 200 ° C. in the middle of the process, or after heating at 150 ° C. for 2 hours, the heating temperature may be 200 ° C. for 2 hours.

  Alternatively, a pinching member may be used to fix it in accordance with the position in contact with the semiconductor device, and heating may be performed in a non-pressurized state. Thereby, the curvature at the time of hardening can be reduced.

  In addition, this process [A3-1] can be omitted when the curing of the resin layer 4 has progressed and completed in the above-mentioned process [2].

  Further, in this step [A3-1], alloying may or may not be promoted between the terminal 242 and the bump electrode 30 and between the terminal 14 and the bump electrode 30, respectively.

  [A3-2] Next, the terminal 14 of the mounting substrate 1, the terminal 242 of the semiconductor element 2, and the bump electrode 30 are heated. Thereby, alloying is promoted between the terminal 242 and the bump electrode 30 and between the terminal 14 and the bump electrode 30. As a result, the terminal 14 of the mounting substrate 1 and the terminal 242 of the semiconductor element 2 are reliably electrically and mechanically connected via the bump electrode 30.

  Here, in the step [A3-1], the resin layer 4 has already been cured. Therefore, even if the terminal 14, the terminal 242 and the bump electrode 30 are heated for alloying, the mounting substrate 1 and the semiconductor element 2 are fixed by the cured resin layer 4. Warpage is suppressed from occurring.

  The specific heating temperature in this step is not particularly limited, but as an example, it is preferably Tm-30 ° C or higher and Tm + 200 ° C or lower, more preferably Tm-15 ° C or higher and Tm + 50 ° C or lower, and Tm− More preferably, it is 5 ° C. or more and Tm + 50 ° C. or less.

  In addition, the heating time in this step is not particularly limited, but for example, it is preferably 1 second or longer and 30 minutes or shorter, and more preferably 5 seconds or longer and 10 minutes or shorter.

  By heating under such conditions, alloying can be promoted more smoothly between the terminal 242 and the bump electrode 30 and between the terminal 14 and the bump electrode 30.

(B)
[B3-1] In the method (B), the semiconductor device in which the semiconductor element 2 and the mounting substrate 1 are bonded is heated. Thereby, the resin layer 4 is cured, and alloying is promoted between the terminal 242 and the bump electrode 30 and between the terminal 14 and the bump electrode 30.

  Thereby, the resin layer 4 is cured, the mounting substrate 1 and the semiconductor element 2 are bonded by the cured resin layer 4, and the terminal 14 of the mounting substrate 1 and the terminal 242 of the semiconductor element 2 are connected to the bump electrode 30. And mechanically and mechanically connected to each other.

  Here, in the step [2], the mounting substrate 1 and the semiconductor element 2 are stacked in a state in which the occurrence of warpage is suppressed. In this state, the resin layer 4 is formed in the step [B3-1]. Harden. Therefore, the mounting substrate 1 and the semiconductor element 2 are bonded together in a state where the occurrence of warpage is suppressed.

  The specific heating temperature in this step is a temperature at which hardening of the resin layer 4 and alloying between the terminal 242 and the bump electrode 30 and between the terminal 14 and the bump electrode 30 are simultaneously performed. Although not particularly limited, as an example, it is preferably Tm-30 ° C. or higher and Tm + 80 ° C. or lower, and more preferably Tm−15 ° C. or higher and Tm + 50 ° C. or lower. Thereby, the resin layer 4 is cured and alloying is promoted without greatly affecting the bump electrode 30. As a result, the mounting substrate 1 and the semiconductor element 2 can be bonded with more sufficient strength via the resin layer 4.

  In particular, when the Tm is less than Tm, the bump electrode 30 is not melted, so that the bump electrode 30 can be prevented from being largely crushed even when this step is performed under pressure.

  In addition, the heating time in this step is not particularly limited, but is preferably, for example, 30 minutes to 5 hours, and more preferably 1 hour to 3 hours.

  Furthermore, the atmosphere in this step may be either an air atmosphere or an inert gas atmosphere.

Further, the pressure of the atmosphere may be under normal pressure or under pressure.
For example, the specific pressure is preferably set to 0.4 MPa or more and 1.2 MPa or less, more preferably 0.6 MPa or more and 1.0 MPa or less. In addition, generation | occurrence | production of the void in the resin layer 4 can be suppressed or prevented exactly by hardening the resin layer 4 under pressure.

  By heating under the above conditions, alloying can be promoted more smoothly between the terminal 242 and the bump electrode 30 and between the terminal 14 and the bump electrode 30.

  Note that in this step, a pinching member may be used, fixed in accordance with a position in contact with the semiconductor device, and heated in a non-pressurized state. Thereby, the curvature at the time of hardening can be reduced.

(C)
[C3-1] First, the mounting substrate 1 and the semiconductor element 2 are pressed against each other while heating the semiconductor device in which the semiconductor element 2 and the mounting substrate 1 are joined. Thereby, alloying of the terminal 14, the terminal 242, and the bump electrode 30 is promoted.

  As a result, the terminal 14 of the mounting substrate 1 and the terminal 242 of the semiconductor element 2 are reliably electrically and mechanically connected via the bump electrode 30.

  Here, in this step [C3-1], the mounting substrate 1 and the semiconductor element 2 are pressed against each other. The load at this time is not particularly limited, and may be pressed against each other with a high load compared to the step [2], but preferably pressed against each other with a low load compared to the step [2]. . Thus, when alloying is promoted between the terminal 242 and the bump electrode 30 and between the terminal 14 and the bump electrode 30, the load causes the load between the terminal 242 and the bump electrode 30 and between the terminal 14 and the bump electrode 30. The bump electrode 30 can be accurately suppressed or prevented from being crushed by the terminal 14 and the terminal 242 while preventing the peeling due to the warpage of the semiconductor element at a high temperature with the terminal 30.

  The specific heating temperature in this step is not particularly limited, but as an example, it is preferably Tm-30 ° C or higher and Tm + 160 ° C or lower, more preferably Tm-15 ° C or higher and Tm + 100 ° C or lower, and more than Tm. More preferably, it is Tm + 80 degrees C or less. Thereby, sufficient alloying is promoted between the terminal 242 and the bump electrode 30 and between the terminal 14 and the bump electrode 30.

  In addition, the heating time in this step is not particularly limited, but for example, it is preferably 1 second or longer and 30 minutes or shorter, and more preferably 5 seconds or longer and 10 minutes or shorter.

  By heating under such conditions, alloying can be promoted more smoothly between the terminal 242 and the bump electrode 30 and between the terminal 14 and the bump electrode 30.

  Furthermore, the pressure when pressing the terminal 14 and the terminal 242 together in this step is specifically 500 kPa or less, preferably 300 kPa or less, and more preferably 100 kPa or less. Thereby, the protrusion of resin can be suppressed.

  On the other hand, the lower limit value of the pressure for pressing the terminal 14 and the terminal 242 together in this step may not be set, but is preferably 1 kPa or more, and more preferably 5 kPa or more. Thereby, even if there is a repulsive force of the resin layer 4, the distance between the terminal 14 and the terminal 242 can be easily maintained, so that the metal bonding generated between the melted bump electrode 30 and the terminal 14 and the terminal 242 can be maintained. Reliability can be further increased.

  In the step of cooling after heating to such a temperature, the pressure when pressing the terminal 14 and the terminal 242 together may be set higher than the pressure in the step [2], but may be set lower. .

Note that the pressure applied when the terminals 14 and 242 are pressed against each other is such that the load applied when the mounting substrate 1 and the semiconductor element 2 are pressed against each other overlaps the upper surface 152 of the mounting substrate 1 and the lower surface 251 of the semiconductor element 2. It is obtained by dividing by the area of the portion (the area of the common portion). For example, when the area of the common part is 100 mm ² (when the semiconductor element 2 of 10 mm × 10 mm is used), 1 kPa or more and 500 kPa is a load of 0.1 N or more and 50 N or less between the mounting substrate 1 and the semiconductor element 2 It corresponds to the pressure generated when.

  Moreover, in this process [C3-1], although hardening of the resin layer 4 advances, it has not reached completion.

  [C3-2] Next, the semiconductor device in which the semiconductor element 2 and the mounting substrate 1 are joined is heated at a temperature lower than the melting point of the bump electrode 30.

  Thereby, the resin layer 4 is cured, and the mounting substrate 1 and the semiconductor element 2 are bonded by the cured resin layer 4.

  Here, the mounting substrate 1 and the semiconductor element 2 are laminated in a state in which the occurrence of warpage is suppressed, and in this state, the resin layer 4 is cured in this step [C3-2]. Therefore, the mounting substrate 1 and the semiconductor element 2 are bonded together in a state where the occurrence of warpage is suppressed.

  The heating temperature (second temperature) in this step is set lower than the melting point of the bump electrode 30 as in the step [2]. Note that the second temperature may be higher or lower than the first temperature.

  The specific heating temperature (second temperature) in this step varies as appropriate according to the melting point of the bump electrode 30, but as an example, it is preferably Tm−70 ° C. or higher and Tm−5 ° C. or lower. It is more preferably 60 ° C. or more and Tm−10 ° C. or less, and further preferably Tm−50 ° C. or more and less than Tm−15 ° C. Specifically, it is preferably set to 150 ° C. or higher and 215 ° C. or lower, more preferably 160 ° C. or higher and 210 ° C. or lower, and further preferably 170 ° C. or higher and 205 ° C. or lower. As a result, the resin layer 4 is cured without significantly affecting the bump electrode 30. As a result, the mounting substrate 1 and the semiconductor element 2 can be bonded with more sufficient strength via the resin layer 4.

  Moreover, since the bump electrode 30 is not melted, it is possible to avoid the bump electrode 30 from being largely crushed even when this step is performed under pressure.

  In addition, the time for applying pressure while heating in this step is not particularly limited, but is set longer than the heating time in the step [2], and is preferably 1 hour or more and 5 hours or less, preferably 2 hours or more and 3 hours or more. More preferably, it is less than or equal to the time.

  Furthermore, the atmosphere in this step may be either an air atmosphere or an inert gas atmosphere.

  Further, the heat treatment in this step may be performed under normal pressure or under pressure. When pressurizing, the pressure is preferably set to 0.1 MPa or more and 10 MPa or less, more preferably 0.4 MPa or more and 1.2 MPa or less, and further preferably 0.6 MPa or more and 1.0 MPa or less. Is done. Thereby, it is possible to cure the resin layer 4 in a state where the shape of the resin layer 4 is satisfactorily maintained (for example, a state in which warpage is suppressed) while suppressing the bump electrode 30 from being largely crushed in this step. As a result, a highly reliable electrical connection is finally achieved between the mounting substrate 1 and the semiconductor element 2, and a stacked structure with high dimensional accuracy is obtained even when the mounting substrate 1 and the semiconductor element 2 are stacked. be able to. Further, by curing the resin layer 4 under pressure, generation of voids in the resin layer 4 can be accurately suppressed or prevented.

  In addition, the heating temperature in this process may be changed from 150 ° C. to 200 ° C. in the middle of the process, or after heating at 150 ° C. for 2 hours, the heating temperature may be 200 ° C. for 2 hours.

  Alternatively, a pinching member may be used to fix it in accordance with the position in contact with the semiconductor device, and heating may be performed in a non-pressurized state. Thereby, the curvature at the time of hardening can be reduced.

Here, FIG. 3 is a diagram illustrating an example in which two semiconductor elements 2 are provided on the mounting substrate 1.
In the example shown in FIG. 3, two semiconductor elements 2 are mounted on a single mounting substrate 1 at a predetermined distance. The distance between the semiconductor elements 2 is not limited, but is, for example, about 50 to 500 μm.

  In such an example, when the resin layer 4 protrudes from one semiconductor element 2, depending on the amount of protrusion, it interferes with the mounting region of the other semiconductor element 2, and the mounting of the other semiconductor element 2 is hindered. In addition, a cutting line may be drawn between adjacent mounting regions when the mounting substrate 1 is cut into individual pieces, but the resin layer 4 protrudes from the semiconductor element 2 on the cutting line. In such a case, the cutting tool cannot recognize the cutting line and may not be able to cut.

  Therefore, the above-described problem is solved by suppressing the protrusion of the resin layer 4. As a result, the distance between the semiconductor elements 2 can be shortened. Thereby, high-density mounting of the semiconductor elements 2 mounted on the mounting substrate 1 can be realized, or the number of pieces cut out from one mounting substrate 1 can be increased.

  The amount of protrusion of the resin layer 4 is preferably 80 μm or less, and more preferably 50 μm or less. According to the present invention, the probability of suppressing the amount of protrusion of the resin layer 4 within such a range can be increased.

  Note that the two semiconductor elements 2 provided side by side can be separated into pieces by cutting the mounting substrate 1 between the semiconductor elements 2 thereafter.

  On the other hand, another semiconductor element 2 may be stacked on the semiconductor element 2 mounted on the mounting substrate 1 as described above, if necessary. Thereby, a laminated body in which a plurality of semiconductor elements 2 are laminated is obtained.

FIG. 4 is a diagram illustrating an example in which two semiconductor elements 2 are stacked on the mounting substrate 1.
In the example shown in FIG. 4, another semiconductor element 2 is stacked on the semiconductor element 2 shown in FIG. 2. The two semiconductor elements 2 may have different configurations, but in this example, they have the same configuration. Further, the terminal 243 of the lower semiconductor element 2 and the terminal 242 of the upper semiconductor element 2 are electrically connected via the connection portion 3. Further, the upper surface 252 of the lower semiconductor element 2 and the lower surface 251 of the upper semiconductor element 2 are bonded via the resin layer 4.

  By stacking the plurality of semiconductor elements 2 in this way, the semiconductor elements 2 can be mounted three-dimensionally. Thereby, a semiconductor device that is small in size and high in density is realized. In addition, since the wiring length between the semiconductor elements 2 can be shortened, the power consumption and performance of the semiconductor device can be reduced.

  In such an example, when the upper semiconductor element 2 is stacked on the lower semiconductor element 2, the above-described steps may be sequentially performed. Thereby, even when a plurality of semiconductor elements 2 are stacked, highly reliable electrical connection can be achieved.

On the other hand, when two (plural) semiconductor elements 2 are stacked as shown in FIG. 4, first, after mounting the two semiconductor elements 2 on the mounting substrate 1 by the mounting process described above, the two mounted semiconductor elements 2 2, the heating process may be performed collectively. Even with this method, the same effect as described above can be obtained. At the same time, the number of steps can be reduced by performing the heating step collectively. Thereby, the manufacturing process of the semiconductor device can be simplified.
The number of stacked semiconductor elements 2 is not particularly limited, but is, for example, about 2 to 50.

<First Modification>
FIG. 5 is a cross-sectional view for explaining a first modification of the circuit member connection method according to the embodiment.

  The modification shown in FIG. 5 is different from the circuit member shown in FIGS. 1 and 2 except that the bump electrode 30 is provided on the terminal 14 of the mounting substrate 1 and is not provided on the terminal 242 of the semiconductor element 2. This is the same as the connection structure.

  Even if the position where the bump electrode 30 is provided in this way, the same effect as described above, that is, a highly reliable electrical connection between the mounting substrate 1 and the semiconductor element 2 can be achieved.

<Second Modification>
FIG. 6 is a cross-sectional view for explaining a second modification of the circuit member connection method according to the embodiment.

  The modification shown in FIG. 6 is different from the circuit member connection structure shown in FIGS. 1 and 2 except that the bump electrode 30 is provided on both the terminal 242 of the semiconductor element 2 and the terminal 14 of the mounting substrate 1. It is the same.

  Even if the position where the bump electrode 30 is provided in this way, the same effect as described above, that is, a highly reliable electrical connection between the mounting substrate 1 and the semiconductor element 2 can be achieved.

<Third Modification>
FIG. 7 is a cross-sectional view for explaining a third modification of the circuit member connection method according to the embodiment.

  The modification shown in FIG. 7 is different from that shown in FIG. 1 except that the semiconductor element 2 is used in place of the mounting substrate 1, that is, the semiconductor elements 2 are stacked and the semiconductor elements 2 are turned upside down. It is the same as the connection method of the circuit member shown to -4. In other words, in the present modification, when two semiconductor elements 2 are stacked, the element surface of the upper semiconductor element 2 (the surface on the side where the wiring layer 22 is provided with respect to the semiconductor chip 21) is lower. They are stacked face down so as to face the semiconductor element 2 side.

  Specifically, in the semiconductor element 2 according to this modification, the protective film 23, the wiring layer 22, and the semiconductor chip 21 are stacked in this order from the bottom of FIG. In addition, the semiconductor element 2 according to this modification includes a through electrode 241 that penetrates the semiconductor chip 21 in the thickness direction, and a terminal 243 that is provided at the lower end of the through electrode 241 and protrudes downward from the lower surface of the semiconductor chip 21. And a terminal 242 provided at the upper end of the through electrode 241 and protruding upward from the upper surface of the semiconductor chip 21.

  Here, in the present modification, the bump electrode 30 is provided on the terminal 243 of the semiconductor element 2.

  Even when the stacking surface (mounting surface) of the semiconductor elements 2 is changed in this way, the same effect as described above, that is, while the protrusion of the resin layer 4 is suppressed, between the semiconductor elements 2 (between circuit members) A reliable electrical connection can be achieved.

  As mentioned above, although this invention was demonstrated based on suitable embodiment, this invention is not limited to these.

  For example, in the circuit member connection method, an arbitrary step may be added to the embodiment.

Hereinafter, specific examples of the present invention will be described.
1. Preparation of sample for evaluation (Example 1)
[1] Preparation of resin layer <Preparation of resin varnish>
First, the components shown in Table 1 were mixed at a mass ratio shown in Table 1, and dissolved and dispersed in methyl ethyl ketone to prepare a resin varnish having a component concentration of 50% by mass.

<Production of resin film (resin layer)>
Next, the obtained resin varnish was applied to a base polyester film (base film, Toray Industries, trade name Lumirror) to a thickness of 50 μm, dried at 100 ° C. for 5 minutes, and a thickness of 25 μm. A resin film (resin layer) having a flux function was obtained. Thereby, the resin layer No. 1 was obtained.

<Evaluation of resin film (resin layer)>
Next, the minimum melt viscosity and viscosity ratio η ₁ / η ₁₀ of the obtained resin film were measured as follows.

≪Measurement method of minimum melt viscosity≫
The resin film is laminated to 500 μm, and the temperature of the resin film is increased from 40 ° C. to 250 ° C. at a temperature increase rate of 10 ° C./min using a rheometer (HAAKE) (“MARS III” manufactured by Thermo Scientific). While raising the temperature, the viscosity was measured at a rotation speed of 1 Hz, and the minimum value of the measured value was taken as the minimum melt viscosity.

≪Measurement method of viscosity ratio≫
A resin film is laminated so as to have a thickness of 500 μm, and using a rheometer (HAAKE) (“MARS III” manufactured by Thermo Scientific), η ₁ [Pa · s], 180 as a viscosity after 50 seconds at 180 ° C. and 1 Hz. Η ₁₀ [Pa · s] was measured as a viscosity after 50 seconds at 10 Hz at 10 ° C., and the ratio (η ₁ / η ₁₀ ) between the two was calculated as the viscosity ratio.

[2] Preparation of member Next, a silicon wafer on which circuit elements and wirings were formed was prepared. A terminal made of Cu is formed on the circuit surface of the wafer, and Ni and Au are plated at a thickness of about 1 μm on the top of the terminal. Further, a Cu pad is exposed on the back surface of the wafer, and a bump electrode made of SnAg lead-free solder having a melting point of 221 ° C. is provided on the pad.

  Next, the resin film prepared in [1] was attached to a silicon wafer so as to cover the bump electrodes. And the base polyester film was peeled and only the resin film was transferred.

  Next, the silicon wafer on which the resin film was attached was cut into individual pieces together with the resin film to obtain a semiconductor element with the resin film. The size of the obtained semiconductor element was 10 mm × 10 mm, the number of bump electrodes was 408, and the thickness was 0.3 mm.

  On the other hand, a silicon mounting substrate was prepared in which Cu pads (terminals) were formed and Ni and Au were plated at a thickness of about 1 μm on top of the Cu terminals. The mounting board had a size of 6 inches and a thickness of 0.625 mm.

[3] Connection between members Next, a semiconductor element with a resin film was picked up by a flip chip bonder and placed on a mounting substrate.

  In this process, first, the semiconductor element was pressed against the mounting substrate at 200 kPa (20 N) for 10 seconds while the bump electrode was heated to 180 ° C. (mounting process). A similar mounting process was performed using a plurality of mounting substrates and a plurality of semiconductor elements, respectively. The maximum speed (terminal approach speed) when pressing the semiconductor element against the mounting board was set to 0.1 mm / second.

  Subsequently, the bump electrode was heated at 180 ° C. for 120 minutes in a nitrogen atmosphere pressurized to 800 kPa (0.8 MPa) (first heating step). As a result, the resin film was cured, and the terminals were connected to each other through the connection portion converted from the bump electrode.

Subsequently, the bump electrode was heated at 220 ° C. for 10 minutes in a nitrogen atmosphere at atmospheric pressure (100 kPa) (second heating step).
As described above, an evaluation sample obtained by stacking semiconductor elements on a mounting substrate was obtained.

(Examples 2 to 20)
Resin layer No. produced using the components shown in Table 1. Samples for evaluation were obtained in the same manner as in Example 1 except that any one of 1 to 5 was used and the members were connected to each other under the connection conditions shown in Table 2.

  In Table 1, the resin layer No. corresponding to the present invention. About 1-5, it describes with the "Example."

(Comparative Examples 1-8)
Resin layer No. produced using the components shown in Table 1. Samples for evaluation were obtained in the same manner as in Example 1 except that any of 6 to 9 was used and members were connected under the connection conditions shown in Table 2.

  In Table 1, resin layer no. About 6-9, it describes with the "comparative example".

(Comparative Examples 9-12)
Samples for evaluation were obtained in the same manner as in Example 1 except that the members were connected under the connection conditions shown in Table 2.

2. Evaluation of Evaluation Sample 2.1 Evaluation of Connection Reliability 20 evaluation samples obtained in each example and each comparative example were prepared. These were then subjected to a temperature cycle test. In this temperature cycle test, an evaluation sample is exposed to -55 ° C for 30 minutes and then exposed to 125 ° C for 30 minutes as one cycle, and this is performed for 200 cycles and 300 cycles.

  Next, the sample for evaluation subjected to the temperature cycle test was cut, and the cut surface near the bump electrode was observed with an electron microscope. Subsequently, the bonding state between the bump electrode and the terminal was inspected based on the observation image and the conduction state between the terminals. And the inspection result was evaluated in light of the following evaluation criteria.

<Evaluation criteria for connection reliability>
A: After 300 cycles, the bonding state between the bump electrode and the terminal is good with all 20 pieces. O: After 200 cycles, the bonding state with the bump electrode and the terminal is good with all 20 pieces. Table 2 shows the evaluation results in which one or more bonding states between the bump electrode and the terminal are defective.

2.2 Evaluation of amount of protrusion of resin film The samples for evaluation obtained in the examples and the comparative examples were observed with an optical microscope. Next, the protruding length of the resin film protruding from the edge of the semiconductor element was measured. And the measured protrusion length was evaluated in light of the following evaluation criteria.

<Evaluation criteria for protruding length of resin film>
A: The protruding length of the resin film is 80 μm or less. ○: The protruding length of the resin film is more than 80 μm and not more than 120 μm. X: The protruding length of the resin film is more than 120 μm.

  As is apparent from Table 2, the circuit member connection method (example) according to the present invention achieves highly reliable electrical connection between the semiconductor element and the mounting substrate even after the heat resistance reliability test. It was recognized that From this, it is recognized that the occurrence of so-called resin biting is suppressed between the terminals according to the present embodiment.

  Moreover, it was also recognized that the protrusion of the resin film was suppressed well between the circuit members which concern on a present Example.

  On the other hand, in the comparative example, it was recognized that the connection reliability was low or the resin film protruded.

DESCRIPTION OF SYMBOLS 1 Mounting substrate 2 Semiconductor element 3 Connection part 4 Resin layer 11 Base layer 12 Wiring layer 13 Protective film 14 Terminal 21 Semiconductor chip 22 Wiring layer 23 Protective film 30 Bump electrode 152 Upper surface 241 Through electrode 242 Terminal 243 Terminal 251 Lower surface 252 Upper surface

Claims (6)

A first circuit member comprising: a first surface; and a first terminal provided on the first surface side;
A second circuit member comprising: a second surface; and a second terminal provided on the second surface side;
A connection metal having a melting point Tm [° C.] provided on at least one of the first terminal and the second terminal;
It is provided on at least one of the first surface and the second surface, has a flux function, has a minimum melt viscosity of 10 to 10,000 Pa · s when measured at 1 Hz, and a viscosity at 1 ° C. at 180 ° C. ₁ [Pa · s], and a viscosity at η ₁₀ [Pa · s] at ₁₀ Hz, a resin layer having a viscosity ratio η ₁ / η ₁₀ of 3 to 25;
A preparation process to prepare,
A mounting step of pressing the first terminal and the second terminal through the connection metal and the resin layer while heating the connection metal to a temperature lower than Tm;
A heating step of heating the connecting metal that has undergone the mounting step to Tm-70 ° C. or higher and Tm + 200 ° C. or lower;
A circuit member connection method comprising:   The circuit member connection according to claim 1, wherein, in the mounting step, the first terminal and the second terminal are pressed against each other with a load of 0.5 to 10 gf per connection electrode for 0.1 to 60 seconds. Method.   3. The circuit member connection method according to claim 1, wherein in the mounting step, a maximum speed in a process in which the first terminal and the second terminal approach each other is 0.01 to 1 mm / second.   The circuit member connection method according to any one of claims 1 to 3, wherein, in the heating step, the resin layer is cured by heating the resin layer to a temperature lower than Tm.   5. The circuit member connection method according to claim 1, wherein at least one of the first circuit member and the second circuit member is a semiconductor component. 6.   The circuit member connection method according to claim 1, wherein the connection metal contains Sn as a main component and Ag as a subcomponent.

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